Fig. 1: Proventia battery chamber layout.<\/figcaption><\/figure>\nSeveral aspects need to be tested during the development phase of the modules and packs. Typically, the Battery Management System (BMS) is tested separately using Hardware-in-the-Loop principles, and a reasonably mature BMS is used for physical testing. For physical testing, the aspects outlined below need to be tested.<\/p>\n
Real-world performance simulations<\/h3>\n
Like any engine that goes into a production vehicle, electric powertrains need to be tested on real-world drive cycles. This will ultimately be done as a complete vehicle test on the road, including the motor and inverter. At earlier stages, the real-world performance can be tested using a battery cycler, which can simulate the load that the vehicle\u2019s powertrain would require (the amount of energy drawn by the vehicle to power it down the road). Electric and hybrid vehicles also re-charge the battery under braking, which can also be simulated.<\/p>\n
Charging and discharging performance<\/h3>\n
One of the most contentious issues around electric vehicles is charging, so clearly, this needs to be thoroughly tested. Battery cyclers can simulate a variety of chargers, and it is possible to bring in commercially available chargers to test pack charging.<\/p>\n
Effects of temperature and humidity<\/h3>\n
The environment that vehicles (and their components) need to work in is massively varied. Even in mainland Europe, temperatures can reach over 40\u00b0C, and temperatures can rise much higher inside the vehicle. In Northern Europe, Russia, and North America, temperatures can drop well below -20\u00b0C, and in Asia, humidity can reach above 90%. There are different standards depending on which markets the battery or vehicle manufacturers want to sell into.<\/p>\n
What is required for battery testing?<\/h3>\n
A few vital bits of equipment are needed to perform the necessary tests. As described above, the most critical piece of equipment is the battery cycler, which can charge or discharge the pack and simulate the vehicle\u2019s load. The most important aspects to consider for the cycler are the voltage and current profile it can deliver and the responsiveness of the cycler. The faster it can respond, the more accurately the simulated drive cycles can be recreated.<\/p>\n
An automation and data acquisition system controls the simulation of the drive cycles and monitors the temperatures and communications to the pack under test. This is often split into a regular desktop PC and a real-time operating system for deterministic testing.<\/p>\n