Quoting "a number of reliable industry sources," Toronto Star reporter Tyler Hamilton posted on his personal blog that battery maker A123Systems has quietly acquired Hymotion of Ontario, Canada.

Hymotion, originally formed as an integrator for hydrogen-based vehicle fuel solutions, has emerged as a leading company with expertise in converting hybrid vehicles into plug-in electric models.

The two firms have been working together to convert a small number of vehicles in California (see Prototype pluggable hybrid contract awarded in LA) and three vehicles of a possible 400 for New York State.

While it sells its high performance lithium ion batteries in a number of industries, A123 is increasingly targeting automotive applications. It is working with General Motors, for instance, to provide batteries optimized for plug in hybrid vehicles through its automotive partner Cobasys.

A123Systems’ batteries are to be evaluated in prototype Saturn Green Line Vue plug-in hybrid SUVs later this year. GM recently announced its intention to produce a Vue Green Line plug-in hybrid SUV that has the potential to achieve double the fuel efficiency of any current SUV.

A123Systems and Hymotion did not immediately return calls for comment. Spokespeople for A123Systems reached by the Cleantech Group said they were caught by surprise by the news, and were seeking guidance from company executives at the time of writing.

We'll update this story as we receive information.