weisstechnik Salt spray test chamber (stainless steel) for lithium-ion batteries with test piece temperature control

WHY – The challenge.

FEV Europe GmbH ?has built the world's largest development and test centre for high-voltage batteries for electric vehicles in Saxony-Anhalt. A wide variety of tests are carried out on 15,500 sqm and in around 70 facilities.

These include salt spray tests to test corrosion resistance in accordance with GS 95024-3-1 sections K06 and K07 and other standards. In the tests, lithium-ion batteries are brought to temperatures of -40 °C to +80 °C and exposed to a spray of 5% NaCL water solution at varying temperatures for a specified time.

The cold is supplied via the central refrigeration system. The turnkey salt spray test chamber shall be provided with safety equipment according to the determined hazard level.

HOW – The idea.

To withstand the temperature changes, the test chamber and all components installed in it must be made of high-quality stainless steel (V5A). The salt solution in the test chamber is nebulised via 2-substance nozzles arranged in special spray channels on the side walls. The salt solution is nebulised in the test chamber with humidified, heated compressed air according to the injector principle. This ensures a uniform salt mist distribution over the entire test chamber area of 1.5 +/-0.5 ml /80 cm2/h.

The test chamber is heated by electric heaters. For heating, cooling, humidifying and dehumidifying, a recirculation system is provided on the rear wall. Due to the poor thermal conductivity of stainless steel, the stainless steel heat exchangers integrated in this system must be dimensioned larger in order to achieve the required temperature change rates.

WHAT – The solution.

The salt spray test chamber has a 16 cm3 test chamber for testing lithium-ion batteries (packs) at varying temperatures in a saline atmosphere. The test chamber and the fixtures are made of corrosion-resistant V5A stainless steel. For installation in the pit provided by the customer, the chamber is compactly built on a base frame and allows floor-level access. For ventilation of the test chamber after a test, a fan is integrated for blowing out with air from the installation room. The salty exhaust air must be led outside on site.?

The required safety devices for tests on lithium-ion batteries have been taken into account to a certain extent. The test chamber was set up in a separate area, additional safety equipment was provided by the customer.