In a conference call discussing the opening of its patents today, Tesla CEO Elon Musk mentioned in passing that BMW had passed through the company's offices earlier in the week:

For high-speed charging in particular, I think that's a great area for commonality among manufacturers. In fact, the team from BMW was visiting Tesla last night. We talked about potential ways to collaborate, and one of them was on the Supercharging network. We're more than happy to have other manufacturers use our Supercharging network and / or to build superchargers and install them, and then maybe have some sort of cross-use agreement.

Now, BMW spokesman Kenn Sparks has confirmed the meeting. "Both companies are strongly committed to the success of electro-mobility and discussed how to further strengthen the development of electro-mobility on an international level," he says.

Musk suggested that the two companies discussed a variety of issues — not just Superchargers — but the rapid growth of Tesla's high-speed charging network is certainly one of the elephants in the room. The charging system that Tesla uses is incompatible with the standard used by effectively every other automaker; Musk has long defended it as being technically superior and better looking, but it's left the nascent EV market with a critical schism that divides already limited resources for expanding infrastructure. With this week's patent moves, other manufacturers have a new opportunity to back Tesla's system at little cost. It's an option that has apparently piqued BMW's interest.

For its part, BMW has moved aggressively on its own EV program recently, launching the workabout i3 and hybrid i8 supercar in recent months. That may have spurred this week's meeting — and with the means already in place for getting electric cars from one American coast to the other, Tesla's charging tech must make an appealing target for any automaker that's committed to going big on electrics.