The German Association of the Automotive Industry (VDA, Verband der Automobile Industrie) has defined a standard for lithium-ion cells to the automotive industry.
There are a number of different lithium-ion cell types and chemistries for the automotive industry and each OEM has its own customized battery pack. The three main cell types are cylindrical cells (18650), pouch cells, and prismatic can cells. The main reasons for a standardisation of the lithium-ion cells are driven by cost and quality.
The proposed standard will define cell dimensions and not requirements for technical features like material usage. There is a need to distinguish between high power applications (for BEVs) and high energy applications (for HEV), and a compromise between the two (for PHEV vehicles).
The main trend for high quality lithium-ion cells is the prismatic cell type, where the cells are placed in a prismatic container and laser-welded to keep the electrolyte inside the container over time.
Some of the big OEMs have already decided to use the standard cells in coming electrical vehicles.
Even the test procedures for lithium-ion cells will be standardised in the future, for example the needle and bar brush test.
The standardisation of the lithium-ion cells is a key to achieve low cost and high quality cells for the automotive industry to meet the lifetime requirements of 10-12 years.
Vattenfall Research and Development