Leak testing is a mandatory quality control procedure for all batteries produced in the automotive industry. Ensuring the airtightness of the battery housing is essential to guarantee optimal performance, safety, lifespan, and cost efficiency. Over time, external environmental factors such as humidity may penetrate the housing and interact with internal components, leading to potential degradation of the battery system.

Battery leak rates are typically extremely small, requiring highly precise measurement techniques. For this purpose, the mass flow method is commonly employed, especially for its ease to be used in a production setting of large products. This method consists of evacuating both the battery under test and a reference volume considered leak free to a defined pressure level. Once the target pressure is reached, the pump is shut down and the two volumes are connected. As a battery can never be perfectly airtight, air gradually enters the housing, causing a pressure increase. This results in a pressure difference between the battery and the reference volume, generating a measurable mass flow that allows the battery leakage rate to be determined.

In an industrial production environment, achieving high measurement accuracy and good repeatability remains challenging. Constraints such as takt time requirements, environmental disturbances and the integration of parallel testing with cooling systems introduce significant uncertainties into the leak testing process. Moreover, process optimization is difficult due to the limited availability of information regarding internal airflow behavior during testing.

The approach proposed in this research is the development of a numerical model capable of simulating the complete leak testing system and procedure. The objective is to gain deeper insight into the physical phenomena governing the interaction between the airflow and the battery components during the test. The Smoothed Particle Hydrodynamics (SPH) method is employed to model the transient compressible flow within the system. Initially, the leak testing procedure is reproduced for a simplified configuration and subsequently extended to a full battery setup. This numerical framework enables detailed analysis of the airflow dynamics and provides a foundation for proposing potential optimizations of the leak testing process.