The voltages of traction batteries in electric vehicles today are typically in the range of 400 to 800V and may in future aim at values of 1500V, since higher voltages can achieve higher performance with lower losses. The energies in these accumulators are enormous and can cause considerable damage in case of failure. Safety devices in electric vehicles ensure that the high voltages and energies in the high-voltage batteries do not endanger people – neither the driver, passengers nor first-aiders in the event of rescue after an accident.
Even in the event of a crash, it must be ensured that no dangerous voltage can reach the body of the vehicle. To this end, fuses are used that very reliably disconnect the energy storage system before live parts can bend and make contact. Assuming that a short circuit nevertheless occurs in the vehicle as a result of the crash, currents of several kiloamperes must be reliably separated. This is done, for example, with the aid of so-called pyro-fuses, which break the electrical connection with a small blast, similar to the ignition pills used in airbags, which are common in the automotive industry. Pyrotechnic fuses are a safety-relevant component and must therefore be tested intensively.
In order to prove the triggering behavior of such a component under simulated short-circuit conditions, a current source is required that can supply several kiloamperes of current for a few milliseconds. In addition, it must generate a realistic battery voltage of up to 1500V while the fuse is tripping.
IRS Systementwicklung GmbH and GvA Leistungselektronik GmbH develop in close cooperation pulse power sources for up to 35kA. This cooperation combines the long and solid experience of GvA for power electronics, high current design and system manufacturing and IRS for software, safety and measurement technology.
Key Facts
- Peak Currents up to 35kA
- Voltage Range up to 1500V
- Pulse Duration approx. 5ms @ 35kA
- Single or optional multi-pulse capability with IGBT technology
Applications
The surge testers from GvA and IRS can be used to test various switching devices in the automotive sector. The current focus is clearly on the separation of traction batteries in the event of a crash, but applications in the energy sector also have similar requirements.
On the one hand, the systems are used for design validation by manufacturers and testing institutes. In addition, random sample tests in production ensure the reliability of products with pyro-fuses.