# Forums

## What about the storage gap disconnect?

This article summarizes the disconnect. I am by no means a battery storage excerpt. But I got B- in physics so I get this. And being in RE for 12 years now and having a mediocre understanding of real time advances in energy storage over the past 3 or 4 years, it seems impossible to bridge this gap without a disruptive technology th at would change, and possibly save in large part, existing climate conditions. Which unfortunately only adds to the um, serious doubt this is possible.

eric.zucker | 2017年12月24日

According to Toni Seba :

Large scale Solar PV comes in at 2.5c/kWh, and 4.5c with battery storage. Well within Elon’s promised 7c/kWh.

Now how they fit 200kWh batteries into the Roadster, and how much it weighs, I really don’t know. We’ll find out in time.

I Wanna Go Fast | 2017年12月24日

A 3300mAh 18650 cell rated at 3.7V is 12.21Wh, or 16,380 individual cells for 200kWh.

For 18650 cells in a triangular pattern over 2 layers (130mm total height excluding wire bonds and cooling), you'd need just under 2.4m^2 (i.e. 1500x1600mm) in plan/top view. That's about right.

Looks to me like it's physically possible, but a few of the variables above will have changed for production (some for good and some for bad).

Happy to hear the details of your physics (math?) calculations that raised serious doubt...

erw698 | 2017年12月24日

The Seba perspective overlooks important factors like existing infrastructure and regulatory barriers at state and federal levels. Here in Mass, storage demo projects are just getting going.

Regardless, storage without space or weight constraints is a different conversation. THAT, is exactly the problem. FAST, what is the weight and depth of discharge of your proposed battery?

I Wanna Go Fast | 2017年12月25日

@erw698, twice as many cells means twice the weight (the enclosure could be similar) and same depth of discharge as current production. Still not clear on what your serious doubt is...

eric.zucker | 2017年12月25日

@erw698, I sort of agree. On one hand, the physical possibility to have clean energy with storage at a lower cost to fossil, nuclear bodes well for the future. Who wants Three mile island or Chernobyl next door.

Where I have trouble is that for many people a car is a status symbol, an extension of one’s habitat, where you leave tools, grocery bags, paper tissues, lipstick or whatever. Shared mobility doesn’t allow that.

Back to the roadster, thanks @fast for the guesstimates. I wonder how the 2170 would fare In your scenario. I read the energy density was improved 30% over the 18650. It’s a substantial gain.

I wonder if the batteries were located differently than the S/X/3 so that the height wasn’t as much an issue. Looks like the ride position reclines more as well.