An electric vehicle (EV) Li-Ion battery (LIB) is either re-purposed for secondary use (such as domestic power back-up) or discarded if some cells have critically failed – studies have shown that >75% of the cells in battery packs that deemed non-fit for automotive usage are still perfectly usable (60% for automotive use, and 15% for stationery use). The proposed EU directive mandates >65% usage of recycled/upcycled material in the manufacture of LIB 2025 onwards.

The current manufacturing method of EV LIBs relies on permanent cell-to-cell joining methods (e.g., welding or riveting) due to lesser overall weight and higher energy density. However, that restricts the recycling industry to take a long-winded method, i.e., fully discharge the pack, crush it to dust, and chemically remove the critical elements like Lithium and Cobalt – which is a very expensive and incredibly wasteful process, since data suggests more than 3/4th of the cells is in perfectly usable form.

We propose to investigate the viability of a unique non-permanent/removable cell-to-cell joining method that would enable easy replacement of damaged cells, thereby significantly reducing the cost to recycle/upcycle Li-Ion batteries for electric vehicles.

We propose two key design changes: a) a textured surface of the busbar and b) securing mechanism for the joint. Assuming a set parameter space, we will undertake controlled laboratory tests to measure the change in electrical conductivity due to fatigue loads from vehicle vibrations. We will also investigate the mechanical integrity of the busbar and securing mechanism by quantifying the elasto-plastic deformation and damage. Importantly, we will undertake a cost benefit analysis to evaluate the expected economic benefits of our proposed design throughout its lifetime, and benchmark against the conventional methods.

Non-permanent joining method would inherently incur some cost and weight penalty as has been widely reported – however, this technology is expected to reduce the overall cost of recycling and upcycling LIBs. We aim to find the break-even point where “repairability” is still profitable by undertaking a cost benefit analysis to evaluate the expected economic benefits of our proposed design throughout its lifetime, and benchmark against the conventional methods.