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Electric vehicles (EVs) are becoming increasingly popular in many regions of the world. However, many consumers still view them as newer technologies. Thus, they won’t feel confident enough to buy them without knowing they’ve been thoroughly tested during the research, development, and manufacturing processes. EV battery testing is critical for requiring manufacturers to show they’ve done their due diligence before putting the products on the market.
Here’s a closer look at how EV battery tests can happen. You’ll also learn about some of the things such screenings can show.
What Do EV Battery Tests Generally Determine?
A range of tests can confirm whether an EV battery pack performs as expected and has no flaws. As a start, manufacturers must carry out leak tests to ensure electrolytes do not come out of the battery cell and moisture cannot enter it. If each battery cell is not gas-tight, the battery’s performance will decrease over time. Plus, humidity from the atmosphere could destroy the cell.
Testing also requires seeing if the battery pack will retain a certain percentage of its original capacity after 10,000 charging cycles. Engineers want to see if the batteries will work safely and effectively when exposed to mechanical and electrical stresses, plus temperature swings.
Can the battery pack withstand vehicle vibrations, immersion in water, or getting crushed during a wreck? Tests can find out, but room for improvement still exists.
Seeking Standardization for EV Battery Tests
Many people probably don’t realize that there are no standardized ways to verify how well lithium-ion batteries perform compared to others on the market. Ira Bloom is a battery researcher working at the Argonne National Laboratory to solve this conundrum.
“Industrial engineers and researchers from governmental and academic labs often devise their own procedures for characterizing lithium-ion batteries based on the battery technology’s intended application. This makes the comparison of any technological innovations extremely complicated,” Bloom explained.
Battery researchers typically look at capacity, resistance, and open-circuit voltage when assessing a product’s electrochemical performance. However, they might measure those things under varying conditions or use different methods each time.
That can change since the Argonne National Laboratory endeavour resulted in a straightforward comparison table of eight lithium-ion testing methods. It shows the pros and cons of each option, the information provided, and the equipment needed to perform the test.
Making Current and Future Batteries Safer
Successful manufacturers know they must continually innovate to impress customers and stay relevant in the marketplace. In terms of EV battery production, that means looking for ways to make the packs show safe, high-performance outcomes. Some testing methods include putting the batteries on electrodynamic shakers to see if they can withstand shocks. Fire-extinguishing agents also deploy if thermal runaway events happen during tests.
EV battery testing also ensures it disconnects from voltage after a crash. There’s a fuse or switch within the battery that should cut the voltage after the impact occurs. If that does not happen, the electric vehicle fails crash tests conducted by the Insurance Institute of Highway Safety (IIHS).
When IIHS testers see how a battery fares after a collision, they also use a thermal camera and thermocouples connected to a battery case to check for hot spots.
Calculating the Ramifications of Battery Fires
Despite efforts made during development, manufacturing, and testing, EV batteries can still catch on fire. Swiss researchers wanted to learn more about the specific hazards of such events. They conducted several tests inside a tunnel and hoped the results would guide battery makers, firefighters, and others interested in or impacted by these accidents.
One test required setting a fully charged EV battery on fire, then calculating the associated toxic residues. Another one measured how far away soot settled from burn sites and what chemicals were present in it.
One takeaway was that the water used to extinguish EV battery fires becomes chemically contaminated to the point where people should not dispose of it via sewage systems. Additionally, the chemicals in the soot are harsh enough to damage unprotected skin. Researchers warned it’s unsafe for untrained people to clean up after these fires, and professionals must handle the job.
Assessing EV Battery Range
When people consider buying electric cars, most wonder whether those vehicles will provide the necessary range to get them where they need to go. Even as today’s batteries offer increasingly longer ranges, people are coming up with creative ways to fill the gaps. One modular charging system gives people 15 miles of range in 15 minutes. Someone also brings the charger wherever they are.
Today’s automakers must follow one of three range-testing protocols established by the New European Driving Cycle (NEDC), Worldwide Harmonised Light Vehicle Test Procedure (WLTP), and the Environmental Protection Agency (EPA). Experts generally say the NEDC is the least accurate of those three.
The EPA gives the best estimate of real-world outcomes American drivers should get. The NEDC and WLTP are both European standards. They primarily assess urban and suburban travel to mimic the driving needs of most Europeans. The EPA is more concerned with highway driving since many Americans will often do it while owning their cars.
When testing whether EV batteries can perform for their stated ranges, the NEDC uses a 20-minute single test cycle, while the WLTP has a half-hour dynamic test cycle. Then, the EPA uses a multicycle test consisting of charging the vehicle fully and parking it overnight before subjecting it to several types of driving until the battery has no more charge.
These tests verify whether EV batteries can last as long as manufacturers claim. However, they also set realistic expectations for consumers, helping them decide if now is the right time to invest in an electric vehicle based on their current or anticipated travel behaviours.
EV Battery Testing Is Essential
This overview explains some of the methods used to verify EV battery performance and safety. Becoming familiar with the procedures is of paramount importance for anyone making or designing the batteries. However, it’s also useful for people in the market for electric vehicles to understand some of the tests performed and what they confirm for the individuals who do them.