Repurposing lithium-ion batteries has proven to be a promising solution  to address the rising number of end-of-life batteries that can be used  for second-life energy storage systems and thus extend their service  life. While previous research has provided valuable insights into the  environmental benefits of battery repurposing, there is still a need to  examine the repurposing process more thoroughly, in order to make  well-informed decisions on the implementation of second-life battery  storage systems. Therefore, this study examines the influence of  different repurposing strategies on the environmental performance of  second-life battery energy storage systems. A life cycle assessment was  conducted, analysing four repurposing cases relating to the exchange of  components, namely i) new battery management system and module casing  (Base case), ii) new battery management system and reuse of module  casing (Case 1), iii) new module casing and reuse of battery management  system (Case 2) and iv) reuse of module casing and battery management  system (Case 3). These impacts were compared to a storage system with  new batteries, to determine the potential environmental benefits and  identify the most suitable repurposing strategy. Our findings  demonstrate significant environmental benefits of second-life battery  energy storage systems across various impact categories and repurposing  cases. The Base case and Case 1 resulted in environmental benefits  across all impact categories. The highest benefits were observed for  metal depletion with savings of 58 % and 61 %, respectively. Increased  savings were obtained for Case 2 and Case 3. However, environmental  drawbacks were identified for freshwater and marine ecotoxicity. In  particular, Case 2 resulted in the highest drawbacks of −22 % and −16 %,  respectively. These can be attributed to the allocation procedure,  particularly affecting the recycling credits of battery management  system recycling. The full allocation of end-of-life impacts and  consequently the recycling credits to the second-life battery has not  only led to a substantial increase in overall savings, but also resulted  in impact categories that originally had disadvantages becoming those  with the highest environmental savings. This study demonstrates the  importance of carefully selecting repurposing strategies for second-life  energy storage systems to maximize their environmental benefits and  avoid drawbacks. Additionally, the results highlight the substantial  influence of allocation procedures on overall environmental impacts,  underscoring the need for clearer methodological guidance on addressing  the multifunctionality of repurposed batteries.

Lithium-ion batteries (LIBs) show high energy densities and are  therefore used in a wide range of applications: from portable  electronics to stationary energy storage systems and traction batteries  used for e-mobility. Considering the projected increase in global demand  for this energy storage technology, driven primarily by growth in  e-vehicles, and looking at the criticality of some raw materials used in  LIBs, the need for an efficient recycling strategy emerges. In this  study, current state-of-the-art technologies for LIB recycling are  reviewed and future opportunities and challenges, in particular to  recover critical raw materials such as lithium or cobalt, are derived.  Special attention is paid to the interrelationships between mechanical  or thermal pre-treatment and hydro- or pyrometallurgical post-treatment  processes. Thus, the unique approach of the article is to link processes  beyond individual stages within the recycling chain. It was shown that  influencing the physicochemical properties of intermediate products can  lead to reduced recycling rates or even the exclusion of certain process  options at the end of the recycling chain. More efforts are needed to  improve information and data sharing on the exact composition of  feedstock for recycling as well as on the processing history of  intermediates to enable closed loop LIB recycling. The technical  understanding of the interrelationships between different process  combinations, such as pyrolytic or mechanical pre-treatment for LIB  deactivation and metal separation, respectively, followed by  hydrometallurgical treatment, is of crucial importance to increase  recovery rates of cathodic metals such as cobalt, nickel, and lithium,  but also of other battery components.

The transport and storage of lithium-ion (Li-ion) batteries — damaged or in an undefined state — is a major safety concern for  regulatory institutions, transportation companies, and manufacturers.  Since (electro)chemical reactivity is exponentially  temperature-dependent, cooling such batteries is an obvious measure for  increasing their safety.

The  present study explores the effect of cryogenic freezing on the  electrochemical and physical stability of Li-ion cells. For this  purpose, three different types of cells were repeatedly exposed to liquid nitrogen (LN2).  Before and after each cooling cycle, electrical and electrochemical  measurements were conducted to assess the impact of the individual  freezing steps. While the electrochemical behavior of the cells did not  change significantly upon exposure to LN2, it became  apparent that a non-negligible number of cells suffered from physical  changes (swelling) and functional failures. The latter defect was found  to be caused by the current interrupt device of the cylindrical cells.  This safety mechanism is triggered by the overpressure of expanding  nitrogen which enters the cells at cryogenic temperatures.

This study underlines that the widely accepted reversibility of LN2-cooling  on a material scale does not allow for a direct extrapolation toward  the physical integrity of full cells. Since nitrogen enters the cell at cryogenic temperatures and expands upon rethermalization, it can cause an internal overpressure.  This can, in turn, lead to mechanical damage to the cell. Consequently,  a more appropriate temperature condition — less extreme than direct LN2 exposure — needs to be found.

Transition to circular economy for lithium-ion batteries used in  electric vehicles requires integrating multiple stages of the value  cycle. However, strategies aimed at extending the lifetime of batteries  are not yet sufficiently considered within the European battery  industry, particularly regarding repurposing. Using second-life  lithium-ion batteries (SLBs) before subsequent recycling can offer  several advantages, such as the development of sustainable business  models, the reduction of emissions, and alignment with UN Sustainable  Development Goals 7, 12, and 13. Using expert and problem-centred  interviews along with an exploratory workshop, this study guides  stakeholders in the battery sector by illustrating the necessary changes  for a more holistic circular economy. Moreover, an extended political,  economic, social, technological, environmental, legal, and additionally  safety-related (PESSTEL) analysis approach is carried out, which has not  yet been used in this context. In this process, barriers, as well as  necessary institutional framework conditions and organisational  requirements for a successful market entry of SLB applications are  investigated. Among others, key barriers relate to the competition with  first-life applications and safety concerns. SLBs require high manual  labour costs for repurposing, along with expenses for expired warranties  and re-certifications. Ownership structures in traditional business  models often result in SLBs and their corresponding usage data staying  under the control of the manufacturers. Market viability, however,  requires a level playing field for both first-life and second-life  operators as well as circular battery and data-sharing business models.  Gathering data on the ageing performance and performing improved safety  testing according to test protocols facilitates the reliable assessment  of SLBs.

With the rise of electric vehicles (EVs) and thus lithium-ion batteries (LIBs), the number of end-of-life (EoL) LIBs after their first life in EVs is about to increase significantly. These end-of-first-life (EoFL) EV LIBs still have sufficient energy density for less-demanding second-life applications like stationary battery energy storage systems (BESSs) or mobile applications (e.g., forklifts, tools). Repurposing EoFL EV LIBs extends their lifespan, offering sustainability benefits and supporting several United Nations (UN) Sustainable Development Goals (SDGs). However, prevailing market entry barriers, such as high repurposing costs, little information on battery history and aging, or lacking performance indicators, hinder the widespread implementation of second-life applications. Thus, this study aims to identify preconditions for considering and selecting useful EoFL LIBs and to determine key performance indicators (KPIs) to minimize economic risks for a successful second-life market launch. KPIs were rated according to importance using a Likert scale, and reference values were introduced. A mixed-methods approach, using expert interviews, an exploratory workshop, and an online survey, was applied. Twelve important preconditions were identified, with the “availability of information on battery specification” and “compliance with standards and regulations” considered very important. In addition, 12 KPIs were derived, covering six economic, three environmental, and three technical and safety-related indicators. The KPIs “state of safety (SoS)” and “resource savings (Rsav)” were rated as highly important. Overall, the findings provide performance measurement guidance for repurposing companies, facilitating the market launch and adoption of second-life applications. Future research can build on these results and investigate variations among different battery types, ultimately promoting a circular economy.

Lithium-ion batteries (LIBs) show high energy densities and are  therefore used in a wide range of applications: from portable  electronics to stationary energy storage systems and traction batteries  used for e-mobility. Considering the projected increase in global demand  for this energy storage technology, driven primarily by growth in  e-vehicles, and looking at the criticality of some raw materials used in  LIBs, the need for an efficient recycling strategy emerges. In this  study, current state-of-the-art technologies for LIB recycling are  reviewed and future opportunities and challenges, in particular to  recover critical raw materials such as lithium or cobalt, are derived.  Special attention is paid to the interrelationships between mechanical  or thermal pre-treatment and hydro- or pyrometallurgical post-treatment  processes. Thus, the unique approach of the article is to link processes  beyond individual stages within the recycling chain. It was shown that  influencing the physicochemical properties of intermediate products can  lead to reduced recycling rates or even the exclusion of certain process  options at the end of the recycling chain. More efforts are needed to  improve information and data sharing on the exact composition of  feedstock for recycling as well as on the processing history of  intermediates to enable closed loop LIB recycling. The technical  understanding of the interrelationships between different process  combinations, such as pyrolytic or mechanical pre-treatment for LIB  deactivation and metal separation, respectively, followed by  hydrometallurgical treatment, is of crucial importance to increase  recovery rates of cathodic metals such as cobalt, nickel, and lithium,  but also of other battery components.

The SafeLiBatt project focused on addressing safety concerns related to first- and second-life lithium-ion batteries (LIBs), particularly their application in battery energy storage systems (BESS). As electric vehicle (EV) batteries reach the end of their automotive use, repurposing them for less demanding applications presents an opportunity to extend their life. However, safety risks such as thermal runaway and toxic gas emissions pose significant challenges. SafeLiBatt, involving experts from BAM and Ineris, conducted extensive tests to evaluate the safety and performance of LIBs through various stages of their lifecycle, focusing on thermal behavior, gas emissions, and potential hazards during thermal runaway events.

In addition to safety assessments, the project explored the environmental and socio-economic impacts of repurposing automotive batteries. Life cycle assessments revealed that second-life batteries (SLBs) show environmental benefits, especially when applied to stationary storage systems, though challenges like ecotoxicity remain. The project provided 11 key recommendations to improve the regulatory framework, standardize safety testing, and promote public acceptance of SLBs. Ultimately, SafeLiBatt underscored the need for further research to ensure the safe and sustainable implementation of second-life batteries.