Repurposing of batteries from end-of-life electric vehicles in stationary storage systems

The recent attempts to reduce global carbon emissions have accelerated the development of electrified transportation systems. Electric vehicles, in this sense, support carbon-free initiatives when they are still on the roads, whereas their production and end-of-life phase need further investigations for environmental considerations. Batteries in electric vehicles are specifically the challenging components because of the material extraction for their production and the hazard they can potentially cause if not disposed of properly. However, circular life cycle thinking suggests exploiting the end-of-use battery stock with different strategies potentially by extending the battery lifetime via reusing or repurposing schemes. This thesis contains four peer-reviewed and published journal articles that address the projection of the upcoming volume of end-of-life battery units from disposed electric vehicles, estimating their state of health at the time of retirement in a hierarchical waste flow representation, the techno-economic evaluation of their second applications in the Irish electricity market, and evaluating the implication of cobalt-free electric vehicle batteries on the potential for lifetime extension through repurposing in electricity markets. Findings include:• The growth of electric vehicles is mainly concerned with transportation regulations, technology advancement, and social acceptance. However, results show that government intervention is considerably more influential in their adoption than market availability. The expected volume of battery stockpile for different levels of regulations and market growth is estimated, showing that a substantial energy capacity within the retired batteries will be available. This signifies the likelihood of second-use market creation. Furthermore, the impact of the potential existence of second-use markets for electric vehicle batteries on their primary adoption has been examined and found to be directly proportional to the price gap between new and used batteries.• A considerable repurposing potential has been found by categorizing the state of health of batteries coming to end-of-life. The hierarchical health representation of retired batteries is useful for refurbishment businesses to scale their investment based on the estimated secondary supply of batteries for high energy demanded applications for which the healthier batteries fit the best (above 85% or 90%), whereas the others (between 80 to 85%) can be used for less demanding applications such as back up storage. Similarly recycling operators will be able to scale appropriately while considering the export rate since repurposing does not always take place in the original market.• The highest financial return is expected from retired batteries repurposed in reserve services in the Irish electricity market compared to energy trading applications. Although they are good candidates for less demanding applications in power systems, their huge upcoming flow to the end-of-life stream will exceed the demand for grid service applications; thus, the allocation of healthier ones is suggested for energy applications. The financial feasibility of their deployment in energy trading is shown to be sensitive to factors such as renewable penetration, battery price, and inflation, meaning that the future changes in energy structure and battery market should embrace the residual value within them.• Comparing the financial feasibility of repurposing two different Lithium-ion battery types inspired by the market shift toward cobalt-free batteries, it has been found that Lithium Iron Phosphate batteries respond more frequently to price fluctuations in energy markets compared to Nickel Manganese Cobalt ones, resulting in improved financial returns. Although cobalt-based batteries have higher energy density and are easier to deploy in vehicles, the issue of cobalt in their supply chain and their lower cycle life comparatively, mitigate their advantage.</p

Estimating the availability of energy storage capacity from used electric vehicle batteries on a national scale

Moving toward a zero-carbon transport system accelerates the diffusion of batteries in society through electric vehicles. This so-called “clean transport”, as kind as it is to the environment during its lifetime, could be a burden for waste management at end of life if not managed properly. A circular waste management system, alternatively, suggests exploring the appropriate actions and policies to create the right environment for the second use of end-of-life batteries. A temporal estimation of the remained capacity in end-of-life electric vehicle batteries enables us to find the fitting second-use applications. This paper will present a model which has been developed for Ireland which combines (i) predictions for the adoption of electric vehicles by class, (ii) vehicle lifetime estimates based on a combination of current EV & ICE vehicles, and (iii) estimation of end-of-life battery generation and associated reuse capacity. The model computes a range of scenarios to estimate the potential availability of EV batteries for secondary use in Ireland out to 2050. Our estimation shows that a scale of several ten, several hundred, and a few several thousand megawatt-hour energy capacities would be available by 2050 in small, medium, and large class vehicles

Is shifting from Li-ion NMC to LFP in EVs beneficial for second-life storages in electricity markets?

While electric vehicles are promising to reduce carbon emissions on the road, from a holistic life-cycle view,  further environmental considerations in the production and end-of-life management of their batteries are  required. Recently, circular end-of-life thinking has been promoted with strategies to increase retired batteries’  lifetime through second-life as lifetime extension is typically favoured in life cycle assessment. However, standardization of these strategies toward recycling or repurposing paths is recommended for different Li-ion  chemistries. This categorization mainly concerns the cobalt-containing cathode Li-ion batteries i.e., NMC  which is the dominant technology for transportation, and the alternative technology i.e., LFPs with a more recent  attention toward them in automobile sector due the cobalt scarcity in the supply chain. This technology shift will  impact their end-of-life management at the retirement. In this arrangement, the economic priority of repurposing  such battery chemistries needs quantification. This study evaluated the financial return of repurposing retired Li-ion NMC and LFP batteries for energy arbitrage applications in power systems. The feasibility of repurposing is  examined in the Irish and Queensland’s markets. Results show that retired Li-ion LFPs respond to price fluctuations more frequently with a higher financial return compared to NMCs; thus, they have higher potential for  repurposing as such their greater integration in new vehicles is promising from a circular economy perspective.  Different rates of return have been observed for various sizes of systems and battery durations. The financial  benefits are more prominent for a one-hour battery in a medium system compared to half and two-hour durations  and a smaller system. A sensitivity analysis shows that even spending the same capital cost as a new system for a  repurposed system results in a marginal financial return in a competitive electricity market like Queensland’s,  whereas further incentives toward circular-enabling business models from local authorities will effectively make  such investments feasible.  </p

Financing the recycling of long life products under extended producer responsibility -a case study of PV

This paper presents an estimation of the quantities of WEEE arising for the Solar PV waste stream in Ireland up to the year 2050. Solar PV will be a new WEEE waste stream in Ireland, one which has a significantly longer lifetime compared to the majority of other WEEE streams. As such, the Solar PV WEEE recycling operations and considerations need to be financed. Estimations of the quantities of WEEE arising into the future will be essential for such financing decisions to be made at the present time. The work presented in this research estimates the quantities of Solar PV arising across both residential and commercial installations for Ireland up to the year 2050. It also discusses some of the options available to finance the recycling of this waste stream under an extended producer responsibility framework

End-of-life electric vehicle battery stock estimation in Ireland through integrated energy and circular economy modelling

While electric vehicles bring numerous environmental benefits during their lifetime, they could be a burden for waste management at the end of life if not managed properly. A circular waste management system, alternatively, suggests exploring the appropriate actions and policies to create the right environment for second-use applications. Such regulatory measures primarily require a temporal estimation of the volume of the end-of-life electric vehicle batteries which helps to distinguish the suitable applications, time, and level of investment in the repurposing market. From an end-of-life flow perspective, the profile of the end-of-life battery stock follows the growth of the electric vehicle market over time and vehicles’ survival age. However, the level of uncertainties about the future trend of these vehicles and their efficiencies makes the end-of-life estimation highly challenging. This paper addresses these uncertainties in end-of-life battery stock estimation in Ireland by (i) modelling the electric vehicle market diffusion based on government policies and customers’ preferences, and (ii) estimating electric vehicle lifetime based on a combination of current electric & conventional vehicles. Having the distribution of primary and end-of-life batteries over time, the impact of added value to electric vehicles due to the battery repurposing on their adoption in the first place is investigated. Results confirm the significant influence of government policies on the electric vehicle adoption profile. The temporal estimation of the reuse capacity of the end-of-life batteries indicates that how different levels of regulations and second-use support schemes end up to a different amount of reuse availability in end-of-life battery stock, ranging from several hundred to a few thousand megawatt-hours in 2050. Results also show that to what degree a potential second-use market for end-of-life electric vehicle batteries would increase the growth rate of electric vehicle uptake in Ireland