Johnson Controls serves this market by providing a variety of automotive batteries like lead-acid for traditional gasoline-powered vehicles, AGM (Absorbent Glass Mat) for start-stop vehicles and Li-ion for hybrid and electric vehicles.
They're readying black wooden fume boards--hive lids lined in absorbent black felt on which they will drizzle butyric acid, the active ingredient in rancid butter.
This would eliminate what has historically been the only performance advantage of lead acid in starter battery applications, and is expected to considerably increase the value proposition of A123's Engine Start battery as a lighter-weight, longer-lasting alternative to absorbent glass mat (AGM) and other lead acid batteries.