Battery Modules

General Structure

Modules will consist of two plastic top plates, 32 cells, two copper dimple plates, strips of compression foam and a delrin end plate as shown below

The delrin end plates isolate each cell and distribute clamping force across the whole module. The foam underneath the end plate assist in distributing force, and the copper end plates are compressed into the cells, held by the plastic cell holder. The dimples allow for errors in the alignment of cells, and are bolted together at the end of each module to form a series connection. 

Additionally, the modules will be strung together in a string of 6 modules, with 6 lengths of coated threaded rod through all modules to provide clamping pressure and create the parallel connections. 

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This design requires an entire string of modules to be removed at once to service one module, but allows the battery box to be a simpler design, and does not require each module to be fixed in space. Additionally, using steel threaded rod that is coated for HV requirements will provide repeatability compared to nylon threaded rod, which quickly loses it's thread.

Copper Dimple Plates

Dimple plates will be waterjet to reduce manufacturing times and increase accuracy of the plates. We will be dimpling the plates ourselves using an in-house jig. This jig uses ball bearings and a matching die plate, with light pressure applied, to create wide, short dimples in the copper plates. 

Attached below are the manufacturing procedures for the modules