Life cycle assessment of the second use of lithium-ion batteries from hybrid and electric vehicles

Conference poster, 2019

The number of vehicles with lithium-ion batteries (LIBs) is increasing. When these batteries no longer fulfill the requirements for transportation, they still contain approximately 70% of their capacity. From a resource point of view, it is desirable that they become part of other applications, e.g. energy storage. This may have a large influence on the feasibility of future energy systems, assuming that there is an increase of intermittent energy generation from renewables. The second use of these batteries has the potential to decrease impacts both through avoiding production of new batteries and through enabling more renewable energy. But if this is to be accomplished, there are environmental questions that have to be evaluated.

This paper presents the first results of a life cycle assessment (LCA) of the second use of LIBs from hybrid and electric vehicles in energy storage applications. This LCA is done within the scope of a research and development project in which battery manufacturers, car companies, energy management system providers, end users and recycling companies take part. The goals of the LCA are (1) to determine which the environmental hotspots in the assessed system are, and (2) to determine under which conditions second use of LIBs are most beneficial from an environmental point of view. As an example of such a condition, the time that a battery is used in a car, and subsequently in an energy storage application, may influence its environmental impact. There are several possible scenarios for how the second use of LIBs is compared to its alternatives. One such alternative is comparing to newly-produced, dedicated storage batteries that are available on the market. Another alternative is to compare second use of these batteries to no second use of them, e.g. material recycling.

The results of the LCA are used by the project partners to further develop a system in which discarded vehicle batteries can be put to environmentally beneficial second use. This contribution also provides guidance on how to assess the second use of LIBs from electric or hybrid vehicles by considering several scenarios for comparison of their performance. Furthermore, variation in system variables, such as the life length of LIBs, is used to explore how to improve or optimize their second use.