MS16 Battery Cell
- Shem Kim
- Shem Kim
Description
The battery cell is the smallest unit of energy within our battery pack. Selection of a suitable cell is important, as the cell specifications will dictate our pack configuration, and the pack configuration will dictate the design of the battery system (overall geometry, enclosure, module design, thermals, etc).
Here’s a quick aside about ASC2024 max battery restriction vs ASC2026 max battery restriction (not necessary to read, just a cool fact):
ASC 2024 regulations restricted the SOV battery pack by setting a maximum weight per regs 8.2.A.1. The exact weight depended on the specific chemistry used. MS15 used a Li-Ion NMC chemistry cell, giving it a 20kg weight limit.
One small problem with limiting the batteries based on weight, was that some top teams who had access to ultra-high (gravimetric and volumetric) energy dense silicon nanowire anode cells from Amprius Technologies ended up having a significant battery capacity advantage. UMichigan reported having 3kWh more energy than a conventional Li-Ion battery pack, and Innoptus reported having 30% more energy than their previous battery pack [3].
Most likely to prevent already successful teams from having an even stronger advantage over everyone else, WSC and ASC decided to move away from limiting battery storage by a weight limit and have moved to limit the battery by setting a maximum energy (11MJ or ~3.05kWh for WSC2025, waiting for reg-drop from ASC for ASC 2026).
The entire MS16 battery cell selection will be split into two main parts:
Candidate cell selection + sample testing from distributor(s)
Mass testing of chosen cell to filter our outliers/lower quality cells
Resources
[3] https://amprius.com/solar-cars-challenge/