Clarios Plans Improved Lead-Acid Batteries for EVs

Clarios, the world’s largest supplier of lead-acid starter batteries for conventionally powered cars, also sees big opportunities for full-electric vehicles.

That’s because EVs still require 12-volt lead-acid units to help start the primary high-voltage lithium-ion battery and power auxiliary components.

Currently, off-the-shelf 12-volt batteries are used for such applications. But that’s likely to change with next-generation EVs.

Bespoke Optimization

“There’s a lot more thought going into the overall electrical system now,” notes Craig Rigby, Clarios’ vice president of technology. He says the trend is toward customized systems to better optimize performance capabilities and packaging flexibility as well as enhance safety safeguards.

One likely change, Rigby says, will be a greater focus on power capabilities rather than capacity. The former (measured in kilowatts) is the maximum amount of electricity that can be output at a single time, while usable capacity (kilowatt-hours) is the amount of electricity stored on a full charge.

This is expected to result in smaller 12-volt units with reconfigured internal components, Rigby notes.

AGM vs. Flooded

The EV 12-volt market is split between absorbent glass mat (AGM) and enhanced flooded (EF) systems, usually mirroring what the base piston-powered vehicle uses. AGM is considered a more robust system that lends itself to automatic stop-start systems, while EF systems are designed for an extended life and with a larger number of charging cycles.

Clarios provides both types of batteries. But Rigby says AGM devices have more potential for EVs, citing greater packaging flexibility and reliability benefits.

While an AGM can be packaged virtually anywhere in a vehicle, EF batteries are more limited because they emit hydrogen gas.

Some carmakers have placed in the front (front trunk), but Rigby says this limits storage space. Due to serviceability requirements, he also doesn’t expect 12-volt batteries to be packaged with their lithium-ion counterparts in new skateboard-style EV platforms.

“The industry still is sorting out the best position,” he notes.

AGM batteries also are better suited to take over and provide temporary backup power if there is a failure in the lithium-ion battery. Flooded batteries are more prone to become unstable over time due to stratification issues caused by the free flow of acid.

Rigby says there also will be a greater emphasis on fault mitigation strategies and monitoring battery health in future EVs. “What’s been a passive device, now is becoming much more integrated and dynamic.”

What’s Next?

Clarios also has a 2-year-old partnership with Toshiba to produce dual-battery systems. The 12-volt architecture teams a Clarios lead-acid unit with a Toshiba lithium-ion battery, which the partners say can provide some of the benefits of a 48-volt mild-hybrid system—such as stop-start and regenerative braking—but with less complexity and at a “significantly” lower cost.

The first production application is due next year.

Clarios provides about one-third of the batteries used in new vehicles and to the replacement market. The latter accounts for 75% of the supplier’s business.

The company, which was divested from Johnson Controls last year, aims to increase its annual battery production from about 150 million units to more than 200 million in the coming years.

“Lead-acid batteries are simple, reliable and are easily recyclable,” Rigby asserts. “But we still need to continue to evolve how we design and produce them for future vehicles.”