Test adapter set as a replacement for the pressure equalization elements for leak testing of the HV battery

Description

To increase the range of e-cars, the energy density of battery cells is constantly increasing. At the same time, the housings are becoming lighter, thinner-walled and thus more pressure-sensitive. For this reason, the housing of HV batteries must be ventilated and de-aerated during uphill and downhill travel, under different operating conditions or for temperature compensation, among other things. Up to now, this has usually been done by a porous PTFE film. However, this reacts sensitively to mechanical influences and contamination and can impair air permeability and ultimately the pressure equalization function in normal operation.

In addition, gases or high heat can develop suddenly in battery housings in the event of an accident or due to foreign bodies. For this to happen, the pressure and heat must be able to escape abruptly, otherwise the housing risks bursting. This is a danger for the vehicle and its occupants. That's why every battery needs 100 percent reliable emergency degassing. In the past, this was only possible by piercing a rupture disc with a pin at corresponding pressure differences, which caused it to wear out or become non-functional.

Recently, pressure compensation elements (e.g. from the manufacturers DIAvent, Freudenberg Sealing Technologies, etc.) have become increasingly popular.

• aeration and deaeration as well as
• emergency degassing

in one component. The great advantage of these pressure compensation elements is that they are suitable for continuous use, do not wear out and can continue to be used even after an emergency. These pressure compensation elements are independent components that are either snapped or screwed into place.

Why do these pressure compensation elements have to be removed and installed?

During the leak test of an HV battery, these components have to be removed because the leak test pressure is higher than the response pressure of the pressure compensation elements. Thus, the test pressure would be relieved via the pressure compensation elements, making only a limited leak test possible.

How must the pressure compensation elements be removed and installed?

To ensure an unrestricted leak test (according to the specifications), the original component "pressure relief valve" must be removed using the appropriate OEW 02 tool for loosening and installing the pressure compensation elements and replaced by a test cap / test adapter PSBG 01_LR.

What are the test lock and the test adapter required for?

• The test cap - in case the test pressure is introduced or measured elsewhere (in the HV battery housing).
• The test adapter - in case the test pressure has to be introduced via the opening of the DAE.
• Test cap and test adapter - in the event that two pressure equalization elements are installed on an HV battery.