The New Thing in Green Tech: Micro-Hybrid Batteries

The battery challenges of micro hybrids are easy to understand. Starting an engine 15 times during a typical daily commute uses about eight times more energy than a single engine start. It's not a one-for-one increase because restarting a warm engine is easier than starting a cold one, but the increased starter demands are massive. An even bigger problem is powering the accessories during engine-off intervals, a task that can demand up to 10 times more energy than the starter. When you work through all the calculations, a micro hybrid demands 90 to 100 times more work from its battery than a car without stop-start.

The flooded lead-acid starter batteries we've all come to know and hate simply can't cope.

Since automakers know that conventional starter batteries can't withstand the demands of micro hybrids, they're all using cutout systems as a work-around. These systems disable the stop-start function whenever the battery isn't ready for another cycle. It's a suboptimal solution because a disabled stop-start system can't conserve fuel, but it's the best car companies can do until better batteries are available in relevant volumes.

In public, the automakers are all building micro hybrids as a core element of their regulatory compliance strategies. Behind the scenes, they're all putting tremendous pressure on battery manufacturers to quickly upgrade their products while controlling costs. For the first time in decades, the battery business is changing rapidly.

The first response from major battery manufacturers, including Johnson Controls(JCI) and Exide Technologies(XIDE) was to introduce enhanced flooded batteries that perform up to four times better than conventional batteries and can be made in existing factories. The second response was aggressive capital spending to increase production capacity for absorbed glass mat, or AGM, batteries that perform up to 10 times better than conventional batteries.

From battery manufacturers' viewpoint, their efforts to boost performance by a factor of up to 10 times while controlling costs are nothing short of heroic. From automakers' perspective, there's still a huge gap between the 10 times the battery manufacturers are delivering and the 100 times the industry needs at a price point that doesn't push payback periods into the forever range.

That gap represents a wide-open window of opportunity for energy-storage innovators that can fill the "white space" with new products that offer significant performance gains at a suitable price point. It's a daunting challenge, but not an impossible dream.