Out of curiosity, with the recent release of their patents, is Tesla going to be enabling other car manufacturers to purchase these batteries? Standardising on a housing module across manufacturers seems a 'good thing' for the general consumer.
It would probably depend on how much extra capacity they have. The Tesla vehicles are in high demand and only going to be in more demand when they start rolling out the Tesla 3 (which is really the 4th Tesla isn't it, I guess they're referring to it being the 3rd generation with the Model S and X being the same generation).
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A huge growing market will be batteries in homes. Germany is trying to push it to go from 30% of photovoltaic self-consumption up to 70% (when the sun shines, people usually are away at work). The excessive electricity is sold to the network.
This requires between 5 and 10kWh storage capacity (compared to the 50+kWh of a Tesla) for a single family home. The current price is about 20€cts/kWh for the storage over the whole lifetime. So it is not economic yet, but it should be within a few years and I hope that Tesla will contribute to it. Solar costs about 15€cts/kWh and electricity from the network is around 25€cts/kWh. When solar will reach 10€cts and storage 10€cts/kWh, the market will be very important.