# Are there any high energy density (i.e. zinc-air or lithium-manganese dioxide) batteries without high internal resistance?

For my wild life camera, I want a small cell that can provide 0.5W for 8 hours or more. It doesn't seems rechargeable lithium ion batteries have that energy density. I don't mind if the cell is non-rechargeable, so I've considered the lithium coin cells and zinc-air batteries.

But it seems the internal resistance on those are terrible: For a CR2477, I estimate the resistance at 910 ohms! Energy density = 2.96 MJ/L

For a 675 hearing aid cell, I estimate 34.7 ohms. Energy density = 6 MJ/L !

So if I use those, there's no way I can draw 0.5W, if at all, without having all the energy consumed by IR? (is IR the only factor causing lower capacity?)

Is this a fundamental limitation to those battery chemistries or can someone point me to cells that allow higher current draw?

According to Wikipedia's energy density page, it claims there are non-rechargeable lithium batteries with an energy density of 4.32 MJ/L. That would be awesome, but where do I find them? (I'm only seeing 2.96 MJ/L for a CR2477 coin cell).

• What's the problem with internal resistance? keep it cool, and don't draw much current from it.. invest in a super-capacitor to buffer between the coin cell and the output. Commented Oct 31, 2014 at 10:29
• 0.5W at 3V from a coin cell is 160mA, which is not too bad if the load is not for a long time, you can easily buffer than with a capacitor. But of course, the space taken up by the cap probably outweighs getting a better battery by far Commented Oct 31, 2014 at 10:31
• Good point about using a capacitor. My camera is motion activated so in theory I can power down when no motion has been sensed for a long time. But even if I do it, I think the average power draw will be > 16ma, which I think is already beyond a coin cell's short circuit current. Commented Oct 31, 2014 at 10:48
• wow, that's a pretty hectic camera. perhaps you can find a better, low power camera more suited to this kind of sleep-wake-take-sleep action? Commented Oct 31, 2014 at 10:53
• I forgot to say, my camera board is only 2" x 1", so an 18650 would be too long. Commented Oct 31, 2014 at 12:07