Battery manufacturing has a significant impact on battery operation, quality, maintenance, and service life. Data about batteries (so-called battery data) can help identify how manufacturing affects the performance of battery components, such as pack consistency for LIB (Tian et al., 2020). Battery data has many different data sources at each life cycle stage, providing opportunities for data-driven quality and performance management in battery manufacturing. Digital battery passports (described in section 4.2) will be one mechanism in which battery data can be stored and made accessible across the life cycle. The collection of data on battery use can enable feedback loops into manufacturing production, thereby providing opportunities to improve production processes. For instance, data observations of poor-performing batteries can be correlated to production facilities and even equipment, offering insight into potential sources of flaws.

Battery data can be collected with different approaches like the battery management system, the battery health monitoring and analysis, and the secondary battery system. A battery management system is where key parameters such as voltage and temperature are monitored. It is essential for the EVs quick charging to control energy storage and transfer in batteries (Hannan et al., 2018). Battery health monitoring and analysis tracks battery operation (such as state of charge and state of health) using sensors and data acquisition systems. Collected data are then processed and analysed by algorithms to identify optimizing potential regarding battery lifetime, safety, reliability, efficiency, and cell balancing adjustments (Xing et al., 2011; Omariba et al., 2019). The secondary battery system prioritizes the measure of energy density performance for LIBs, nickel-metal hydride and nickel-cadmium batteries (Dutta et al., 2023).

Emerging studies focus on improving EV battery performance and health utilizing technologies like machine learning algorithms, decentralized data systems, and statistical models (Aenugu et al., 2020; Vidal et al., 2020; Yang et al., 2023). These data-driven approaches enable state-of-charge, state-of-health, and lifetime prediction and adoption of circular strategies of batteries. However, the main challenge is that the identification of patterns and trends is highly reliant on the quantity and quality of collected battery data (Wang L. et al., 2020). The lack of standardized tests and measurements hinders the collection of quality data and the application of data-driven approaches. Generalizability of data-driven approaches can be improved by addressing challenges posed by academia and industry and establishing standards for communication and comparison of results. Data-driven approaches also offer promise to trace problems with batteries back to manufacturing issues. Data-driven quality and performance management can help analyse root causes and develop preventive measures in battery manufacturing.

The cost of the battery constitutes a large share of the total cost of an EV. This cost is though predicted to successively decrease (Nykvist and Nilsson, 2015; Mauler et al., 2021; Shahjalal et al., 2022). The quality of the battery is, in addition to cost, also related to performance, reliability and safety. Methods and strategies to reduce quality losses and identify quality problems are of vital importance for competitiveness and sustainability in modern EV battery production. Focusing on dimensional quality, examples show how variation in the gap between cells in a battery deteriorates the quality of laser welding of the busbars (Sun et al., 2021), how cell-to-cell variation affect the structural behavior of the battery pack (Arora et al., 2018), or how too much pressure in a module (partly) due geometrical deviations, might lead to thermal runways (Zhang et al., 2022).

Battery cells need to meet many different requirements, both material and process related, such as correct levels of moisture in electrode and separator material, but also accurate alignment between the anode and cathode surfaces to ensure that the active materials are in close contact over the entire surface area (Kwade et al., 2018). The dimensional tolerances are usually tight, and Kwade et al. (2018) mention that the tolerance of the thickness of the electrode can typically be around a few μm.

Many aspects of quality assurance can be applied to batteries. Strategies to minimize quality losses can be grouped into:

• Robust design, including simulation techniques

During design phases, robust solutions (i.e., design concepts that are insensitive to variation) should be sought out. Simulation tools can be used to evaluate the effects of different alignment strategies during module and pack assembly (Arora et al., 2018). Several existing computer-aided tolerancing tools can be used for this purpose (Söderberg et al., 2017; Schleich et al., 2018). Tolerancing is also an important activity to secure fulfilment of quality requirements without unnecessarily high costs. The effect of geometric tolerances at the assembly level can be simulated and evaluated using variation simulation and other variation management strategies (Schleich et al., 2018). For quality control in production, inspection is crucial, and also strategies to utilize inspection data to preemptively identify problems through trends analysis. Statistical process control, including multivariate quality control to monitor several dependent variables (Kornas et al., 2019) is an important tool. Also, digital twins for quality improvement can be useful (Söderberg et al., 2017). If quality problems remain, effective methods to identify the root causes of the problem must be applied. As with performance management for the production processes, these types of quality assurance are also dependent on known and good data. Metrology and standards are needed to facilitate appropriate data collection for use in validation of techniques and ultimately to create robust repeatable systems.

Battery manufacturing plants are complex systems characterized by substantial process diversity, large volumes of machinery and equipment, and time-variant process relations (Westermeier et al., 2014). This makes maintenance operations a crucial necessity to achieve high levels of operational performance and the ability to meet the growing demand for cells and packs. However, the specific academic research field of maintenance operations in battery production systems is severely lacking, where current state of the art consists mostly of analytical models of total manufacturing costs that treat maintenance as a negligible overhead cost (Duffner et al., 2021a). To stimulate growth and advancement in this research area, smart maintenance (Brundage et al., 2019; Bokrantz et al., 2020) is used as a theoretical and empirical foundation. The concept of smart maintenance (1) originates from practice and thus appeals to the logic and interest of working professionals, (2) is well-accepted and recognized in scholarly literature, and (3) has been empirically linked to higher maintenance performance and productivity (Bokrantz and Skoogh, 2023). This work outlines a series of opportunities and challenges for the four dimensions of smart maintenance (Bokrantz et al., 2020): data-driven decision-making, human capital resource, internal integration, and external integration.

Data-driven decision-making refers to the degree to which decisions are based on data. Improving maintenance decision-making using data is a major opportunity for battery manufacturers, owing to the highly digitalized greenfield factories that generate large volumes and variety of maintenance-related data. This can be used not only for predictive and prescriptive maintenance planning and scheduling but also to discover unknown process relations such as the influence of observable equipment parameters (e.g., vibration) on battery quality performance. However, such development is also challenging due to the newness of production equipment and the nature of scaling a new industry sector that lacks historical data and knowledge of past failures and behaviors of equipment.

Human capital resource is a unit capacity based on individual knowledge, skills, abilities, and other characteristics (KSAO) that are accessible for unit-relevant performance. Being a part of shaping the emerging battery sector is exciting and motivational to many individuals, and battery manufacturers can therefore attract maintenance talent from both local and global labor markets. Owing to the close link between maintenance and sustainability, talent recruitment can also help to increase the status of maintenance as a profession. Still, battery manufacturers face severe constraints in competence supply and need to put considerable emphasis on continuous up- and re-skilling initiatives.

Internal integration refers to the degree to which the maintenance function is a part of a unified, intra-organizational whole. As battery factories are being built from scratch, manufacturers have great opportunities to shape and form organizational designs where maintenance is closely connected to other functions such as production, quality, and purchasing. With fewer legacy constraints and embedded cultures, maintenance organizations can pursue more information sharing and joint decision-making with other actors. Large investments in IT infrastructure can also support the use of integrative mechanisms such as common data platforms and joint information systems. To be successful with internal integration, manufacturers need to overcome the challenges inherent to dealing with large and fast-scaling organizations where it is difficult to establish momentum in cross-functional initiatives. Maintenance needs to be included in the strategic procurement process at the earliest stage possible to prevent unexpected equipment issues during installation and ramp-up.

External integration is the degree to which the maintenance function is a part of a unified, inter-organizational whole. Learning about machinery and equipment in a new sector requires cross-company collaboration and an emphasis on knowledge-building and sharing from a larger population of the same or similar equipment. Establishing this type of external linkage is a major opportunity for maintenance organizations and is driven by a strong industrial interest in sharing and building maintenance excellence together. There are numerous challenges that originate from the global supply chains of battery production equipment, where maintenance organizations need to deal with geographically dispersed suppliers with variations in maturity, processes, languages and culture.

The advancement of information technology in the third industrial revolution significantly promoted the broad implementation of automation in the modern industry toward mass production (Xu et al., 2018; Leng et al., 2022). While battery components are still mass produced, shifting to mass customization at a product level stimulates transformation toward more flexible and agile automation to fulfil increasingly complex manufacturing tasks and the enlarging market of customized products. Among other automation technologies, robots have demonstrated superiority in conducting repetitive and unergonomic tasks quickly and precisely and have been widely adopted in modern production (Wang Y. et al., 2020). Nevertheless, further research is required to address challenges stemming from the lack of cognitive ability in robots.

More agile robotic solutions are desired to automate material handling processes in battery production involving variants of battery components and products (Sharma et al., 2019). Robotic automation can handle generic pick-and-place tasks and robotic inspection in battery production, especially in module and pace assembly (Kwade et al., 2018) and quality control (Sharma, 2024). However, conventional industrial robots are incompetent in dexterous robotic manipulation required for conducting complex operations in compact workplaces or handling flexible workpieces in components assembly (Sharma et al., 2019). Many variants of battery-powered products exist in current production. Meanwhile, the number of variants is expected to keep increasing with product customization. One of the customizable elements could be batteries for higher power or autonomy. A lack of standards for battery designs also leads to an increasingly varied battery structure and layout, exacerbating the challenge for robotic automation (Castelvecchi, 2021).

The numerous variants enable a higher level of customization but impede robotized battery assembly and disassembly that require agile robotic manipulation based on flexible and adaptive motion and path planning. The robotic control system needs to be adaptable to manipulating different objects (i.e., cells, modules, and other components of batteries) and assembly or disassembly operations in battery production. This adaptation requires advanced perception for a robotic control system for manipulating objects and tasks, where visual perception is critical when considering enriched information in visual inputs. To process visual inputs, computer vision techniques have been introduced to robotics and demonstrated their effectiveness in different production scenarios (Zhou et al., 2023). Particularly for battery production, computer vision techniques have been primarily explored, for example, for disassembly operations where battery cables were identified based on 3D point cloud instance segmentation (Brådland et al., 2022). With the recent successful adaptation of deep learning in computer vision, the potential arises to introduce additional computer vision techniques to enable more intelligent decision-making processes in robotized assembly and disassembly in battery production.

Besides full automation achieved solely by intelligent robots, the lack of agility and cognitive ability in robots stimulates research on human-robot collaboration toward human-centric automation (Wang L. et al., 2020) stressed in the recently proposed Industrial 5.0 (European Commission, Directorate-General for Research and Innovation et al., 2021). Human-robot collaboration is expected to enable the system to benefit from the symbiosis between robotic strengths in high accuracy and repeatability and humans’ superiority in agility and adaptability. In battery production, human-robot collaboration can promote the efficiency and agility of automation to address concerns in terms of labour cost, skilled operator shortage, operation ergonomics, and working environment safety (Kay et al., 2022). Nevertheless, guaranteeing the safety of human operators around robots remains a concern. Conventionally, protective equipment enclosing robots, such as physical barriers or laser curtains, is required in automated production for safety purposes (International Organization for Standardization, 2011a; International Organization for Standardization, 2011b). While in collaborative robot applications, new safety challenges exist as human operators and robots collaborate in closer proximity (Gerbers et al., 2018). Though numerous collision detectors have been proposed, their accuracy and robustness in actual production scenarios demand further improvement (Xiao et al., 2023). Besides passive reactions against potential collisions, computer vision techniques can enable active robotic motion and path planning to avoid collision based on human intention recognition and scene understanding, for example, hand gesture recognition, human action recognition, and indoor scene segmentation (Xiao et al., 2023). The active perception and understanding of human intentions, based on recognition of human gestures, eye movement, and haptics, can also improve human-robot interaction to promote the efficiency of human-robot collaboration in battery production, contributing to more intelligent decision-making processes and efficient and safe battery production.

Extended reality (XR) has been identified as one of the enabling technologies of Industry 4.0 and beyond (European Commission, Directorate-General for Research and Innovation and Müller, 2020) offering new immersive mediums of human-interaction with virtual, as well as physical, assets of production systems (Fast-Berglund et al., 2018). It is also a technology that could play a vital role in the current transformation of traditional OEM assembly manufacturing towards battery production and processing.

Ramp-up of battery production through green-field factories, along with its new processes and technologies, is being planned for globally, not the least within the EU. Markets that so far have limited previous experience and knowledge of battery production see an increasing need for decision support early on in the production planning and design phase (European Court of Auditors, 2023). By leveraging XR, it is possible to interact with early plans and designs to empower the decision-making process. Early digital assets, such as our factory-, machine- and product-designs can be visualized and interacted with on a higher immersive level (Jerald, 2016). Allowing for more stakeholders to partake in the interaction, knowledge exchange, and decision making prior to physical construction and commissioning (Gong, 2018). Engineers, suppliers, production staff, industry experts and management, from various locations of the globe, can jointly discuss, review, and validate factory layouts and processes on a 1:1 scale digital model. Thus, providing enhanced planning and designs early in the production life cycle.

XR can also support in the operational stage of battery production. It can be regarded as a cognitive support tool for addressing several issues regarding upskilling and reskilling for the operator which are crucial to accelerate the electrification trend (Mourtzis et al., 2022). Various benefits have been identified for XR to improve upskilling speed and quality during each stage of the training and cognitive assistance process. For example, the following benefits are seen in pre-training:

• Multiple stakeholders’ involvement: The multi-user XR platform enables multiple stakeholders involved for comprehensive understanding about the training challenges, opportunities for decision making on site or remotely (Gong et al., 2020).

During training:

• Customization of progress: The progress could be controlled by the operators and the repeatability could be especially beneficial from beginners through difficult sessions.

And in post-training:

• Data-driven iteration of the training process: The evaluation system will be based on the real data during the training process for optimization of the program (Fabijan et al., 2017).

Virtual reality (VR) can facilitate the virtual workstations and procedures and provide immersive experience and training for the operators in a non-disruptive and risk-free virtual environment while in a quick and easy setting (Krichenbauer et al., 2018; Strojny and Dużmańska-Misiarczyk, 2023). While Augmented reality (AR) can be used in the next step of the continuous training in the physical environment for better spatial cognition (Krichenbauer et al., 2018). A framework utilizing multiple XR technologies in sequence is suggested to accelerate the training and support of shopfloor technicians and operators, and thus ultimately accelerating the upskilling and ramp-up of battery manufacturing capabilities.

Battery manufacturing deals with process management which is about controlling flowing chemicals (flow production) in forming the battery cells, and discrete operations (discrete manufacturing) which are required as battery cells are combined into packs and placed in final products (Kwade et al., 2018). These processes are increasingly automated but also require human interventions for visual and manual checks.

When tasks require manual handling, i.e., picking, lifting, and carrying as well as screwing and running nuts, ergonomics analyses can help ensure that the physical loading is kept below safe threshold values so that no overload injuries occur (Berlin and Adams, 2017). The magnitude, duration and frequency of the strains are important factors. The ergonomics literature suggests thresholds for the strains as well as methods for analysing them. The analysis can be based on measurements and observations of the actual work, or computer manikin simulations of the planned work (Lämkull et al., 2005). The results are often communicated with a colour scale where green means safe, yellow means conditionally unsafe and needs further attention, and red means the task is unsafe and needs redesign.

In addition, cognitive loading in battery production relates to various operations and management tasks such as planning and quality control. While cognitive issues are important even in jobs regarded as simple, mental and cognitive conditions related to attention, concentration, adaption, learning, and planning become more pronounced in complex and extensive work tasks. Simpler jobs may increase in complexity particularly when combined in sequences which can vary due to the higher number of variants produced. A cognitively designed work leads to better product quality and worker wellbeing (Malmsköld et al., 2015; Wollter Bergman et al., 2021). It may also attract people to jobs, making them develop higher skills and stay longer on the jobs.

The widespread societal transformation presents a major global challenge: the need to upskill and reskill the workforce for new or evolving job roles. One of the main hurdles for the battery industry today is to have the right-skilled workforce who can solve the challenges occurring when batteries are produced. When the industry is changing, workers may do new tasks. In this case, work tasks range from process industry to more traditional assembly (Kwade et al., 2018). For workers who are used to traditional tasks in automotive industry, a shift to battery production also leads to a higher demand of skills related to safety. Currently, industry is struggling to find the right-skilled people for battery-related jobs. This results mainly from two parallel phenomena: (1) the demographic change in European countries, the US, and China results in a shortage of available people in the working age (United Nations, 2022), and (2) among the people in working age, not enough candidates have the right skills to meet the battery industry’s demand (Rikala et al., 2024). With this background, the European Commission launched the Pact for Skills with the goal to upskill and reskill 800,000 workers for battery production by 2025. Several other upskilling and reskilling efforts have been undertaken such as the Deep Tech Talent Initiative (EIT Deep Tech Talent Initiative, 2024) and Automotive Skills Alliance (2024).

The LIB value chain comprises distinct stages, each playing a crucial role in achieving circularity. According to Oliveira et al. (2015), mining raw materials for LIBs has a notable environmental impact, leading to issues like water pollution and ecosystem destruction. Costa et al. (2021) suggest mitigating this impact by renewable energy in mining operations and recycling mining waste. Despite optimistic projections (Costa et al., 2021) about recycling LIBs, reducing reliance on natural resources by 50%, mining and exploration will remain essential due to the non-recyclability of all materials. Furthermore, the most carbon-intensive stages of the LIB life cycle—extraction, processing, and production—account for a significant portion of the total carbon footprint (Costa et al., 2021; Chen et al., 2022). Extracting lithium from brine deposits and mining cobalt are energy-intensive processes, contributing to emissions. Additionally, refining raw materials into battery-grade materials involves complex and energy-intensive procedures.

Design plays a pivotal role in circularity; batteries designed for easy disassembly and recycling are more likely to be recycled at the end of their life (Rönkkö et al., 2023). Albertsen et al. (2021) stress the importance of designing LIBs that facilitate repair, disassembly, and recycling, extending the significance of battery design to EV manufacturing, where it serves as a foundational element in technological development. Interestingly, there appears to be reluctance among EV manufacturers to share crucial information about the battery design and manufacturing with recycling firms, as evidenced by Yu et al. (2023).

The production of LIBs involves energy use for assembly and quality assurance, with cathode materials contributing significantly to emissions (Wang et al., 2017). Chen et al. (2022) project substantial emissions reductions in battery production by 2060, primarily through transitioning to greener electricity sources. Although there are ways to reduce the carbon footprint of LIBs, it is crucial to note that the technology is still in its early stages, requiring further research for more efficient and sustainable manufacturing processes. From a technological perspective, battery manufacturing is relatively mature, yet there is room for improvement (such as automation, digital twins, and artificial intelligence) to optimize processes and reduce costs (Wu et al., 2020).

The collection, pre-treatment and recycling of LIBs stand out as crucial activities to enable circular economy. According to Richter (2022), recycling end-of-life EV batteries could substantially meet global demand for cobalt, lithium, manganese, and nickel in 2040. However, waste management poses a major challenge due to the risk of fires and hazardous contamination, necessitating careful handling. Recycling methods, such as hydrometallurgy, direct physical recycling, and remanufacturing with recycled materials, can result in a 51.8% lower carbon footprint compared to battery production with raw materials (Chen et al., 2022). Reuse strategies, outlined by Albertsen et al. (2021), including intensified use, repair, repurposing, refurbishment, and remanufacturing, play a crucial role in extending the life of EV batteries and optimizing their life cycle value. Repurposing batteries in energy storage systems has also been identified as a viable market opportunity (Richter, 2022).

While LIBs were introduced to the market about 30 years ago, they are today considered state-of-the-art power sources for portable devices and EVs (Neumann et al., 2022). As batteries reach their end of use, they need to be handled with care to avoid negative ecological impacts as well as create opportunities for value recovery which is becoming increasingly important for components and materials with high economic value. Despite the rapid progress made with recycling technologies to recover different battery materials, LIBs are still poorly recycled with a large portion of spent batteries going to landfill without any material recovery. One of the challenges for battery recycling is the broad range of battery types (chemistries) cells, modules, packs and overall product designs. To overcome the challenge posed by this diversity and to enable large-scale, profitable battery material recovery, it is essential to consider in early product design the ability to disassemble and sort batteries, as well as to ensure compatibility in pre-treatment and recycling processes.

Among the different types of battery recycling processes the dominant methods used today include extractive metallurgical processes such as pyrometallurgy and hydrometallurgy (Blömeke et al., 2022; Neumann et al., 2022). The recovery rates for these established recycling techniques are already high; e.g., over 98% for lithium, over 95% for cobalt, and over 90% for graphite (Neumann et al., 2022). Pyrometallurgy requires high-temperatures and has a low recovery rate, and hydrometallurgy is a slower process which consumes more chemicals. Modern recycling processes usually combine multiple pre-treatment and recycling methods to achieve higher recovery of valuable metals, such as cobalt, lithium, manganese, and nickel. Thermal pre-treatment can improve the leaching yield and recover rates of these active materials (Petranikova et al., 2022). Substituting primary/virgin material with secondary materials in new battery chemistries can alleviate the resource extraction stress caused by the rapid increase in demand for rare and scarce minerals, but recovered materials remain a low contributor of the total production input to produce batteries (Baars et al., 2021). Some of the main challenges in LIB recycling include resource intensity (process efficiency for recovery lithium in particular), safety concerns due to the high reactivity of metallic lithium and consequently the necessary process developments for LIB pre-treatment.

Novel recycling processes are constantly being explored to improve recycling efficiency (energy and chemicals consumption), reduce costs, and further increase recovery and purity rates. For example, direct recycling or regeneration methods based on defect-targeted healing can reduce the necessary energy and resulting emissions compared to hydrometallurgical and pyrometallurgical methods (Xu C. et al., 2020). Different regeneration processes have different advantages and disadvantages (Zhao et al., 2020). They present promising avenues to reduce the environmental impact of recycling while generating significant economic benefits to create an incentive for their adoption. However, as some of these processes are still in early stage of development, they are not yet deployed at industrial scale. In addition, new battery chemistries (i.e., as discussed later in section 4.3) will require new recycling techniques; for example, lithium sulfur batteries are considered promising options for the future (Neumann et al., 2022), but no recycling process for such batteries exist as of today since they are yet to reach the market.

While there is a strong focus on developing such recycling solutions both in academia and industry, recycling is a lowest-priority circular strategy and thus should be considered when no other valuable or practicable applications for the remaining battery performance exist. Given the impact of battery production, the most desirable circular strategy is to use batteries for as long as possible until performance degrades below a certain acceptable threshold which is typically around 70%–80% of initial capacity. At that point, the battery can be repurposed for other applications with lower requirements such as stationary energy storage. Beyond repurposing, other circular strategies can be considered such as battery regeneration and refurbishing.

Circular battery business practices are being developing around the world and include end-of-first-life activities (such as remanufacturing, refurbishment, repurposing, recycling) and battery leasing in China, Japan, Europe (e.g., Germany and Norway), and the United States (Jiao, 2017; Tao et al., 2022; Gonzalez-Salazar et al., 2023). Battery repurposing in a “second life” application is an important circularity strategy that offers promising business solutions to mitigate supply chain risks related to LIBs, reduces the environmental impact of manufacturing new LIBs, and creates additional economic value (Rajaeifar et al., 2022). Repurposing of EV LIB cells for a second-life application can help limit and extend the useable service time of many critical minerals such as cobalt and lithium. This method of reuse is supported by the fact that EV LIBs are often capable of storing 70%–80% of their original capacity at the end of their first life (Martinez-Laserna et al., 2018). The used LIBs are often suitable for refurbishment for second life deployment as stationary energy storage systems for the electrical grid, communication towers, and renewable energy generation sources (wind and solar farms). There are several international examples of second life implementation in the LIB lifecycles. For example, 4R Energy in Japan collects spent EV LIBs from an automobile OEM, car dealers, and dismantlers. The company inspects, grades, disassembles and reassembles, and sells spent LIBs to (i) the OEM as refurbished LIBs for spare parts, (ii) other users as repurposed LIBs for energy storage systems and other applications (e.g., automatic guided vehicles), and (iii) recycling companies as non-resalable LIBs to be processed as recycled materials (Tao et al., 2022). Another example is Eco Stor in Norway where the company collects spent LIBs from EVs and sells them as stationary energy storage systems. Spent batteries are dismantled and sorted to ensure sufficient remaining battery capacity for repurposing (Wrålsen and O’Born, 2023). Similar activities are taking place in the U.S., an example being a collaborative project co-led by state, university, and private industry stakeholders (Nissan and Seven State Power), which aims for Nissan to repurpose its used EV batteries for use in energy storage systems at their headquarters in Franklin, TN, U.S.

Such opportunities for circular businesses can be expected to expand in the future. When attempting to design sustainable circular battery businesses from both economic and environmental perspectives, the following items need to be considered:

• A vision and goals to be achieved in the business. These should be consistent with circular economy principles.

Research on sustainable circular battery business planning has been progressing by taking a qualitative approach (e.g., Jiao, 2017; Bajolle et al., 2022) and a quantitative approach (e.g., Takata et al., 2019; Huster et al., 2022; Gonzalez-Salazar et al., 2023). Furthermore, a scenario analysis approach by combining narrative stories and quantitative simulations is often taken to explore possible business plans considering future change and uncertainties (e.g., Tao et al., 2022; Schulz-Mönninghoff and Evans, 2023).

Research on battery production requires a life cycle perspective which benefits from the increasing digitalization of industry. Exploring the business models that can better support battery production and commercialization is a task of urgent nature. By embedding circular economy principles in the value proposition of battery systems, industry can explore alternatives, such as the use, results or performance of batteries, over the offering of retention of ownership. One such model is servitization. Servitization is a business model trend which was introduced in the 1970s (Vandermerwe and Rada, 1988). Conceptually, servitization is when the manufacturer retains ownership of assets, focusing on access to assets with business models in the form of a leasing or sharing platform (Ahuja et al., 2020). By shifting towards servitization and adopting service-based business models, the concept of value delivery is decoupled from tangible assets and material resource consumption. Such decoupling of the tangible asset is known as dematerialization. Other potential benefits of servitization include product life cycle extension, competitive advantage, strengthened customer relationships, and more responsible consumption (Kamal et al., 2020).

Despite ongoing research regarding the commercialization of batteries with a life cycle perspective, few vehicle OEMs are providing public information about activities related to the commercialization of circular strategies, such as intensifying use, repair, refurbish, remanufacturing (Albertsen et al., 2021). Recent research proposes that this production paradigm could benefit from a lens where circular business models are considered the go-to alternative, with particular focus in embedding sustainability in battery value chains. It is worth noting that adopting circular business models does not necessarily lead to sustainable business models, a paradox that must be considered and avoided in this context (Blum et al., 2020). Servitization applied to batteries needs to be further explored. It can be expected that with complex value chains, barriers and challenges will require the orchestration of both internal and external resources to succeed. Some influencing factors (such as market forces, regulations, financial incentives, supporting infrastructure or lack thereof, etc.) could be viewed simultaneously as drivers and challenges for circular business models (Jacobs et al., 2022). Available literature has mainly adopted a perspective on batteries restricted to EV batteries: the take-back and servitization models where three archetypes are thoroughly described (Chirumalla et al., 2024). Although end-of-life vehicle take-back is essential for automotive battery recovery (Sopha et al., 2022), this approach shifts the value capture opportunities to the end-of-life and does not take advantage of benefits that could be developed at the design and use phase (Rocha et al., 2019). Servitization could reduce the initial cost of EVs and increase the number of returned EV batteries. Such cost structure combined with governmental incentives can encourage manufacturers to engage in product end-of-life and battery end-of-use management more proactively.

Several servitization models explore different value opportunities within batteries (Chirumalla et al., 2024). Among them is the case of exchangeable battery services, whereby the EV users do not own the battery (Mak et al., 2013). Instead, the batteries are commercialized as a leased product or component, based on a service contract (charged based on usage or distance driven). Battery swapping is another alternative which could provide fast-refuelling service for EVs (Ahmad et al., 2020). In this sense, the many structures for battery-as-a-service business models hold promising potential to avoid long recharging time during long-distance travels. Such business models exist in the Chinese market, where the number of swapping stations grew rapidly, and the expectation is that they will also increase their appearance in the European market. To enable swapping the EV batteries must be designed for swapping. Despite the benefits of servitization, a trend is emerging for larger EVs to go for cell-to-pack or cell-to-body design driven by minimizing cost and weight and maximizing energy density, hindering access for serviceability to handle the cell failures.

LIB production depends on key materials that are sourced from several different geographical regions around the world (European Commission, Joint Research Centre et al., 2018). The process of value creation in LIB production spans from extracting and refining raw materials, to crafting cell components, modules, and assembling battery packs. This culminates in the assembly of the finished product, followed by its useful life, servicing, and ultimately, end-of-life management. This intricate value chain encompasses a sprawling global business network, making them vulnerable to risks. Examples include critical raw material supply shortage (Xu P. et al., 2020), geo-political issues, global supplier dependencies, recycling issues (Harper et al., 2019), the COVID-19 pandemic which brought vulnerabilities to international EV-LIB trade (Hu et al., 2021), and more. If LIB supply chains are to deal with such risks and contribute positively to sustainability, they need to be resilient (Marchese et al., 2018) in terms of increased transparency and flexibility or reduced dependencies in the supply chain.

Resilience is defined as the ability to prepare for anticipated hazards, adapt to changing conditions, to withstand and limit negative impacts due to events, and to return to intended functions/services within a specified time after a disruptive event (VanGeem, 2018). Manufacturing resilience is further defined as the ability of manufacturing companies and their supply chains to anticipate, cope, and learn from disruptions caused by risks so that they can revert to normal or better states of operation (Chari et al., 2023). Risk assessment, which is an important aspect of building resilient supply chains, thus becomes relevant especially from a supply chain perspective, as dependencies exist on both, the upstream and downstream stages (Yan et al., 2020). Building capabilities for suitable resilience and response strategies to deal with risks in LIB production while maintaining the triple bottom line of sustainability will be the next step in building resilient supply chains.

However, LIB value networks require collaborations between partners but this in turn increases dependencies and hence the vulnerability of value chains. Digitalization offers key opportunities and advantages to build the resilience of the LIB value network (Fu and Chien, 2019) by helping them respond faster to disruptive events, improve cooperation between value chain partners (Veile et al., 2022), and increase data transparency and full product transaction traceability (Krima et al., 2019; Zhao et al., 2019). The use of IoT, big data and decentralized data systems technologies (Hastig and Sodhi, 2020; Antônio Rufino Júnior et al., 2022; Tavana et al., 2023) can provide capabilities that further enhance the potential for the tracking and monitoring of the value-creation processes.

Specifically, IoT and big data can support data collection and analysis for battery management and optimizing performance to design sustainable and circular supply chains (Tavana et al., 2023). By agreeing on key events in the battery life cycle, the value chain (from raw material extraction to final product) may be monitored to support timely decisions. In cell manufacturing, tracking individual components’ origin and movement will allow manufacturers to pinpoint the source of any errors and promptly take corrective measures. Decentralized data systems (such as blockchain) can revolutionize how partners collaborate and exchange information and is seen as a vital tool in eliminating forced or child labour (Hastig and Sodhi, 2020). Such systems can also help detect if mines produce more than the expected amounts (which may indicate mineral mixing) and verify responsible purchasing and production practices, among other benefits. Process tacking and monitoring facilitates preventive maintenance, and with the appropriate analysis can reduce resource consumption and related expenses and improve the overall sustainability of the production system. Notably, recent advancements in digital product passports and digital battery passports offer promising solutions for sustainable and circular value chains (Berger et al., 2022). New methods to ensure the security of critical raw material supply (Blagoeva et al., 2020) across the value chain, including upstream and downstream activities, need to be developed.

As discussed in section 3, implementing circular economy strategies such as reuse, remanufacture and recycle (Alcalde-Calonge et al., 2022) can further improve supply chain resilience (Chari et al., 2022; Kurz et al., 2022). Due to the complexity involved in manually disassembling spent EV batteries, human-robot disassembly collaborations have emerged as a promising alternative (G. Yuan et al., 2023). By using real-time dismantling information and fault information data, these collaborative systems will improve operational efficiency, the system’s ability to respond to disruptions and quickly resume disassembly operations.

For the effective growth of a circular value chain in the EV battery industry, reliable information is vital to verify that the product aligns with the principles of ethical sourcing and supply chain traceability (Adisorn et al., 2021; Berger et al., 2022). Presently, gaps exist in the data available within the EV battery landscape, posing challenges to achieving the circular economy model (Jackson et al., 2014; University of Cambridge Institute for Sustainability Leadership CISL and the Wuppertal Institute, 2022). One concept that has emerged as a potential enabler of a circular economy for batteries is the digital product passport. As described by the European Commission, the digital product passport concept relies on unique identifiers and decentralized ledger systems to provide extensive data throughout a product’s life cycle to fill the information voids and ensure transparency and verifiability of the information (European Commission, 2022). As such, a digital product passport is a structured collection of data related to a particular product with a predefined scope and agreed upon data ownership and access rights. The intended scope of the digital product passport includes information related to sustainability and circularity factors, as well as value retention for re-use, remanufacturing, and recycling (CIRPASS, 2023). Emphasizing material traceability and transparency is a critical step to mitigating waste and pollution and facilitating circularity in the battery sector (Geissdoerfer et al., 2017).

In Europe, the Ecodesign for Sustainable Product Regulation (ESPR) prescribes the gradual rollout of the digital product passport starting in 2027. Given efforts to decarbonize the transportation sector through increased adoption of EVs, the battery industry has become a priority (European Commission, 2018). Digital battery passports have thus become a use case for digital product passports in Europe (The Battery Pass consortium, 2023). Similarly, in 2018, China’s Ministry of Industry and Information Technology (MIIT) issued the Interim Regulations on Traceability Management of the Recycling and Utilization of New Energy Vehicle Power Batteries. This regulation aims to establish a comprehensive system for gathering information and overseeing the entire life cycle of EV batteries to determine recycling effectiveness (Cheng et al., 2021; Li et al., 2021; Xu et al., 2021). In the U.S., interest is increasing in advanced battery supply chain traceability and transparency. For example, the Inflation Reduction Act of 2022 aims to drive domestic EV and battery production by providing tax credits to consumers that purchase EVs that meet specific material and component requirements (United States Congress, 2022).

While global efforts and interest in digital battery passports continue to increase, the concept faces several challenges in development and implementation. From a high-level perspective, major challenges can be grouped into key areas:

• Estimating cost and benefits: Agreements as to who funds digital battery passports and who benefits are lacking. The business case for a digital battery passport is needed to articulate benefits and beneficiaries, costs, and funding models along with analysis of different options. Key to creating acceptance of digital battery passport, especially by manufacturers, is the need to develop business models around sharing better product circularity data (Adisorn et al., 2021).

Overcoming these challenges will necessitate collaboration and global consensus on issues such as data needs for circularity, data governance and verifiability, and unification and standardization to create acceptance and garner participation in digital battery passport systems. Metrics need to be defined for sustainability and circularity assessment across product life cycles and could be utilized to prioritize data inputs to digital battery passports. Standards are necessary to support uniform and interoperable data systems, harmonize data inputs and accessibility, and to develop methods for third-party verification of data authenticity. A commercial ecosystem needs to be developed that supports the equitable distribution of digital battery passport costs and benefits, and simultaneously business models should be innovated in support of the digitalization of circularity.

Next-generation batteries constitute a diverse flora of different batteries that challenge the LIB technology in proving either higher energy density or specific energy, being more sustainable and less costly, or have better safety and toxicity characteristics. These include dual-ion batteries, Na- and K-ion batteries, organic and bio-based batteries, Al-batteries, divalent chemistries (Ca, Mg, Zn), sulfur-based and oxygen-based cathodes, and solid-state batteries. In turn, all of these comprise many different subcategories, which thus together comprise thousands of different possible cell chemistries. Commonly, neither of these can yet show the total performance metrics that render them seriously competitive with the Li-ion technology, and some are still at very low technology readiness levels (TRL), and thereby need more research efforts. The most mature examples to date are Na-ion batteries, which generally display considerably lower resource scarcity than Li-ion batteries (Wickerts et al., 2024), and solid-state batteries based on Li-metal (Amici et al., 2022), which rather appear as less sustainable solutions (Mandade et al., 2023).

From a production point of view, there are no major changes involved when transferring from traditional Li-ion to Na-ion batteries; they involve the same type of processing steps performed in the same order (Duffner et al., 2021a) as they use a liquid electrolyte. Solid-state batteries, which use solid electrodes and solid electrolyte, involve profound changes, partly due to the handling of a metallic (Li-metal) negative electrode instead of a carbon porous electrode, and partly due to that the solid electrolyte cannot easily infiltrate the porous cathode. The latter problem needs to be solved differently, taking into account the properties of the solid-state electrolyte, which is commonly a Li-conducting ceramic sulfide or oxide, a Li-salt dissolved in a polymer, or a hybrid between these three categories (Sångeland et al., 2019).

Handling the production of solid-state batteries based on solid polymer electrolytes is the most straightforward way of transferring the process of LIBs to solid-state batteries, since less critical steps need changes. It could be argued that the comparatively easy production of polymer-based solid-state batteries is the cause for their successful implementation in different types of commercial vehicles, compared to the ceramic-based solid-state batteries (Song et al., 2023). The main differences as compared to LIB production are the implementation of the Li-metal anode, that the solid polymer electrolyte material need to be mixed in with the cathode slurry to fill the pores of the positive electrode, and that the polymer electrolyte need to be applied as a specific layer during coating instead of through filling. If solvent-based coating (tape casting, slot die or doctor blade casting, or screen printing) is to be used for the electrolyte casting, the solvent needs to be compatible with other cell components, not least the cathode binder. In order to avoid any such problems, and to also avoid drying of the solvent, extrusion of the polymer electrolyte can alternatively be used, which saves production time and cost (Schnell et al., 2018). As for all solid-state batteries, formation cycling is generally not necessary after production, which is likewise beneficial.

However, the handling of the Li-metal electrode is contributing to several additional steps that need consideration (Duffner et al., 2021b). Lithium is a very adhesive metal, and the processing implicates special challenges for roll-to-roll processes which requires a delicate balance between the pressure and tension to avoid tear or stretch for the application to meet needs of all the dimensional characteristics. Different types of handling tools could be employed; for example, laser for slitting instead of roll-knife slitting. Furthermore, lithium has to be processed in a dry atmosphere or under inert argon atmosphere. Otherwise, lithium will oxidize or form other surface layers that will seriously affect cell performance and ageing. To assure quality of the lithium metal electrode, the lithium metal electrode can be produced directly through extrusion in the battery production line. A so called ‘anode-less’ design, where the metal anode is formed in situ in the battery during charging, would clearly simplify the production of solid-state batteries (Tan et al., 2020), but has so far shown stability issues due to side-reaction and the limited Li content in the cells (Bertoli et al., 2023).

As for solid-state batteries based on solid polymer electrolytes, ceramic materials also need to be mixed with active materials, binders and conductive additives to produce ceramic-based solid-state battery cathodes by slot-die coating onto the Al current collector. Depending on the properties of the active material, which are fundamentally different for sulfidic and oxide solid-state batteries, different handling steps are necessary (Duffner et al., 2021a). The sulfidic materials are highly sensitive to air and often require an inert gas environment. However, they are mechanically ductile and can therefore use a straight-forward pressing step in the cathode formation. The oxides are chemically more inert (although still requiring dry room conditions) but brittle and need a high-temperature sintering step to assure good contacts between the cell components. This is energy and time-consuming, and alternatives such as spray-coating are therefore being studied. All types of processes are significantly more demanding as compared to conventional LIB cathodes.

The production of solid-state batteries also causes limitations in the different cell formats. In short, due to the adhesive properties of Li-metal and the brittleness of the solid electrolyte, pouch cells are needed (Janek and Zeier, 2023). However, solid-state batteries facilitate the use of bipolar configurations, with the single cells connected in series (Jung et al., 2019). Such configuration can be used to increase the cell voltage and to reduce the amounts of current collectors in the cell stack, thereby raising energy density further.

The key to developing sustainable battery production lies in knowing how to create eco-friendly systems from raw material preparation to electrode manufacturing and cell assembly. At present, the high cost and high energy consumption of conventional battery manufacturing has a significant environmental impact, especially the slurry-based electrode manufacturing process which causes 20% of total manufacturing cost, 47% of total energy consumption and another 29% of total energy is consumed by the dry room facility (Li et al., 2020; Liu et al., 2021). This is because of the use of toxic and expensive organic solvent N-methyl-2-pyrrolidone (NMP) which needs to be recovered during electrode manufacturing processing (Kwade et al., 2018; Liu et al., 2021). Replacing NMP with water has attracted significant attention worldwide. This could decrease manufacturing energy by 43% and lower the cradle-to-gate life cycle impacts up to 88% over conventional battery manufacturing (Yuan et al., 2021). Ultimately, dry coating from dry electrode powder to the film would eliminate the use of any solvents, which is beneficial for the current LIB production, as well as important for future solid-state battery manufacturing (Duffner et al., 2021b). This advanced technology offers significant savings in manufacturing costs and reduced CO₂ emissions.

Several advanced dry coating technologies have been proposed and investigated for the electrode formation. A few examples include dry pressing coating technology, dry spray coating technology and electrostatic coating methods (Ryu et al., 2023). The application of the dry coating technology in LIB manufacturing was implemented by the Maxwell Technologies Inc. by directly calendaring the mixed active materials, binder and conductive additive. A free-standing film can be obtained and then laminated on the surface of the current collector (Liu et al., 2021). In the process, a binder fibrillation, in which polytetrafluoroethylene (PTFE) forms long fibres, is important to hold the active materials and conductive materials together. Using a similar method, Meng et al. realized the formation LNMO electrodes at high loadings (3.0 mAh cm^-2) and demonstrated the performance improvement of long-term cycling in the high voltage (4.7 V) for LIB application (Yao et al., 2023). Such a dry coating method can readily fabricate roll-to-roll electrode with controllable thickness and uniform film.

Recently, the electrostatic coating technology for electrode manufacturing has drawn significant attention from both academia and industry in battery manufacturing field. In a fabrication process, the premixed dry particles are charged via a spraying gun, followed by deposit on the ground current collector. The formed dry powder film is controlled by the charging voltage, carrier gas pressure, and the distance between the spray gun and the current collector. Several works have successfully dementated the use of electrostatic coating method to prepare a uniform and controllable electrode (Ludwig et al., 2016). Ludvig et al. used the dry powder electrostatic painting process prepared the lithium cobalt oxide-based electrode. A fast hot rolling process thermally activates the thermoplastic polymer to bind the active material in only a few seconds. The bonding test of the dry deposited particles onto the current collector shows that the bonding strength is greater than a slurry coated electrode. This simply electrostatic coating process also makes it easier to control the microstructure of the deposited electrode. Such dry spraying deposition is a versatile method because it can be widely used for all common active materials particles for LIB. Both roll-to-roll dry coating (binder fibrillation) and electrostatic coating has the potential for practical upscaling of electrodes manufacturing. For the electrochemical performance, a dry coating method could achieve higher active materials loading compared to conventional wet-coated electrodes and result in improved high-rate performance owing to uniform distribution of binder on the active particles.