Economic and Environmental Analysis of the Reuse of EV Batteries
Posted: 23 Jul 2019
Date Written: July 20, 2019
Even though the car buyers are still quite reluctant to purchase an electric vehicle (EV), EV sales are increasing year over year. Besides the driving range, price is probably the main obstacle that EVs have to overcome if definitely they want to win the struggle to the Internal Combustion Engine Vehicle (ICEV), where the battery cost fabrication represents around 30 to 40 % of the final EV price. In addition, EV manufacturers suggest that when traction batteries lose between 20 to 30% of their State of Health (SOH) they should be replaced because otherwise EVs could have unexpected driving malfunctions and safety problems. However, there are many real applications and scientific articles where it is demonstrated that these batteries still have enough energy to be used in other applications, for example, as an ESS (Energy Storage System). Because of that, EV manufacturers see the reuse of batteries as a seriously attractive possibility to reduce the selling price of an EV.
Contrary to popular belief, giving these batteries a second life is not as easy as taking them out of the car and installing them in an ESS. The two most common reuse strategies are to use the entire battery as it was in the car or to disassemble it and use the battery modules. Both strategies have advantages from a technical point of view, although only a few studies have delved deeper into the subject.
This paper deeply analyses which of the two battery reuse strategies has a better economic performance and which of them has a lower environmental impact that will be done by means of Life Cycle Assessment (LCA) methodology. This analysis will be done in different real scenarios.
The research work was conducted using the disassembly of two EV batteries. The batteries analysed were those of Volkswagen e-Golf and Smart Forfour. The dismantling process was carried out at SEAT S.A. technical centre. On the other hand, GaBi software is used for the LCA analysis.
3. Results and Discussion
Direct batteries re-use has some advantages over battery remanufacturing such as faster battery inspection and supervision, easier and cheaper reconditioning processes. In contrast, there are also some important disadvantages such as the need of additional communication interfaces, rigid and heavy systems difficult to manipulate, and the need to know the internal programming of the battery. The latter is a totally confidential element for manufacturers, which means that this first strategy would only be available to those.
On the other hand, battery remanufacturing at module level has other favouring circumstances such as presenting an optimized final product for second life application, BMS (Battery Management System) designed exclusively for second life applications, which improves the performance of these, stackable at module level and the possibility of getting a modular solution. Despite the advantages mentioned, working with modules have significant limitations such as more preparation time; need to build a new configuration and manufacturing processes that are more expensive.
This article deeply analyses both strategies determining the cost and environmental impact and defining which applications suits better for each strategy.
Although both strategies (direct reuse and remanufacturing) have their own advantages, direct reuse most of the times is cheaper, with a lesser impact on the environment. However, the remanufacturing offers a big modularity, which could be more interesting despite their initial drawbacks, which means that economic performance can be much better.
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