Guide for designing EV battery packs using modular cells.

Important to ensure the pouch or prismatic cells are properly compressed. This can take a lot more force than you might think, and can require very strong endplates and either strapping or restraining metalwork.

It's important to have a controlled path for gas to escape in the event of a cell venting. In this case the battery enclosure can quickly fill with hot gases, and if the box is completely sealed this could result in an exploding enclosure. Or more likely in the enclosure rupturing at an uncontrolled location and venting the gases. By using a dedicated burst vent, the location where gases would escape can be controlled. For example rather than risking the hot vent gases from point toward the seats in a vehicle they can be guided to a less sensitive location.

Cell voltage sense wiring must be carefully routed and protected from chafing through. If one or more cell voltage sense wires short to the chassis then a dangerous high voltage fault can occur.