We have seen Cell to Pack and Cell to Body pack designs, now we are seeing talk of Electrode to Pack. The first to talk about this perhaps are 24M Technologies with what they have trademarked as their ETOP system.
In lithium cells with a liquid electrolyte this arrangement would be an issue as the electrolyte would be exposed to high voltage. Typically the electrolytes decompose beyond 4.5V and generate insoluble products such as Li2CO 3. These products can block the micropores on the electrode and generate gas. The result is loss of capacity, performance and more critically is a safety issue.
In solid state cells this issue is solved, however, in semi-solid state cells is this the case? 24M say it has been solved in their press release: 24M Technologies to Unveil Electrode-to-Pack Technology — 24M ETOP™ — at 2023 Japan Mobility Show
A streamlined battery pack system that features electrodes packaged directly into the battery pack, removing the need for individual cells and modules.
The claims are significant:
- Performance: Achieve electrode (not cell) packing efficiencies of over 70%, the highest pack-level volume utilization efficiency available.
- Cost: In addition to its streamlined process and decreased materials usage, it enables unit electrodes to be connected in a combination of series and parallel — an industry first. By eliminating additional connection components, it also further reduces the overall pack cost.
- Range and Cycle Life: Higher packing efficiencies and energy density provide benefits for both EV and ESS applications, boosting range and capacity.
- Safety: The 24M SemiSolid™ Electrode and Unit Cell technology continues to provide unmatched safety when subjected to mechanical abuse.
- Pack Design Flexibility: The 24M Unit Cell can be connected in series, parallel and a combination of series and parallel directly within a pack, enabling configurations that are no longer bound or limited by individual cell voltage (V) and capacity (Ah).