You may have seen engines test on dynamometers, but Rimac does the same thing with its batteries designed for electric hypercars. As with engine dyno testing, this ensures batteries meet performance targets and handle real-world use.
Rimac simulates everything a battery might experience in a car, including acceleration, charging, track use, and highway driving, CEO Mate Rimac explains in a video from YouTube channel Apex One. By running these simulations 24/7, engineers can more or less replicate a lifetime of use in a few months, he said.
Engineers can get all of the data they need while batteries sit on a test stand. While developing batteries for the Koenigsegg Regera hybrid, Rimac simulated a 0-400 kph (0-248 mph) acceleration run this way.
Koenigsegg Regera in bare carbon fiber - Image via Keno Zache Photography/Carage
During tests, engineers monitor many different parameters, including the voltage and temperature of each individual battery cell, as well as temperature of the entire battery pack. Cells are individually selected for use in a given pack, so their characteristics are as consistent as possible.
"If, out of the thousands of cells inside of the car, there is one or multiple cells that are performing worse than the others, that's going to be your limit," Rimac said. Any weak cells can be traced back to their point of origin, he added.
As with internal-combustion engines, batteries work best under very specific conditions. Testing helps figure out what the best operating range is, Rimac said.
Rimac C_Two prototype
When a battery is discharged during testing, the electricity is sent into the grid, which has created a bit of a problem for the automaker.
"The electric company doesn't really like that," Rimac said.
In addition to developing a battery pack for Koenigsegg, Rimac will supply a pack for the Aston Martin Valkyrie, and will work with Hyundai on an all-electric N sports car. Rimac is working to get its own second-generation electric supercar—the C_Two—into production.