Interview with Michal Bruna, Head of Electronics Development and Testing at the Brunswick Battery Development Center
Driving electric means driving safely: Before the battery systems of modern e-cars from Volkswagen hit the road, they have passed a lifetime of comprehensive safety checks. Dr. Michal Bruna is Head of Electronics Development and Testing at the Battery Development Center of Volkswagen Group Components in Brunswick. He explains what release tests the energy storage devices have to undergo.
How are battery systems tested at Volkswagen?
At the Battery Development Center in Brunswick, we test almost every conceivable case that could affect the battery system during a car’s operating life – from accidents to extreme temperatures. The safety of drivers is the most important thing for us. That is why every variant of the battery, including the software, has to prove its safety in more than 5,000 individual tests.
What exactly are you investigating?
Life cycle tests are an important area: We subject the battery systems to stresses in mechanical shocks such as those caused by curbs, railroad crossings or stone chippings. In a two-week vibration test, we simulate the complete life cycle of a vehicle. In other tests, the battery has to withstand thermal shock immersion, such as can occur when driving through cold water. In electric battery test rigs, we test battery systems under different climatic conditions – temperature and humidity – with required charging and discharging currents. At the end, we disassemble each battery system and check its condition.
What is the division of labor within the Group?
In addition to our system tests in Brunswick, there are other tests sites in the company: The Center of Excellence in Salzgitter tests the quality of the battery cells, and Technical Development in Wolfsburg tests the cell modules. This is how we ensure, for example, that each battery can actually achieve the maximum range. The software and control units are tested automatically on so-called hardware-in-loop test benches for functionality, safety, reliability and smooth interaction. And in battery production, the functionality and safety of each battery is checked before it is delivered to the vehicle plant.
How safe are the electronics?
The highest safety standards that exist in the automotive industry apply to battery electronics. This means that a safety-relevant fault may occur after 100 million operating hours at the earliest. In the event of a vehicle accident, the electronics shut down the battery system so that the vehicle cannot become electrically live and the driver and passengers are safe even in this exceptional situation.
What other protection is there for accidents?
The battery is located between the axles of the cars and is thus already well protected by the vehicle architecture. This applies to fully electric vehicles as well as plug-in hybrids. In the event of an exceptionally severe crash, the battery system can still be damaged, of course – but no safety problems should arise. If the airbag deploys, the battery system is automatically disabled. It can only be started and recharged after a safety check in the workshop. This means that maximum safety for the car passengers is also guaranteed here.
Which car do you drive?
A Passat GTE. The hybrid drive is a great solution for me at the moment. In everyday life, I drive almost all distances electrically. On longer trips, I use the combination of the electric motor and gasoline engine. During corona times, however, that hardly ever happens because I’m at home a lot. I recently refueled for the first time in six weeks – a full 15 liters of gasoline.
Passat GTE 1.4 l eHybrid OPF 115 kW (156 PS) / 85 KW (115 PS) 6-speed dual-clutch gearbox DSG: Fuel consumption in l/100 km (NEDC): 1.2 (combined); Electricity consumption in kWh/100 km: 11.5 (combined); CO2 emissions in g/km: 28 (combined); Efficiency class: A+