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For a battery working and chargeable on electrochemical reaction, how does the size of the battery affect its maximal power output?

Specifically, With any chemicals/materials available and current technology level, is it possible to build a micro-battery which is tiny in size yet still "powerful"? How powerful can a tiny battery be, and what chemical reactions/materials should it be built upon, if this is realistic?

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    $\begingroup$ Are you specifically asking about wattage per unit volume? $\endgroup$
    – Todd Minehardt
    Commented Oct 14, 2021 at 0:53
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    $\begingroup$ See also Energy_density_vs_power_density // EDLC = Electric double-layer capacitors. $\endgroup$
    – Poutnik
    Commented Oct 14, 2021 at 8:39
  • $\begingroup$ @ToddMinehardt Yes that could be relevant and actually a very precise description of what I asked. Also I wonder how wattage per volume is affected by the type of materials. $\endgroup$
    – user142857
    Commented Oct 15, 2021 at 18:51
  • $\begingroup$ 2 major factors affecting power density are the rate of charge transfer and the conductivity of active electrode materials + electrolyte.. // For Li-ion cell family is typical that higher power density means lower energy density. $\endgroup$
    – Poutnik
    Commented Oct 16, 2021 at 16:41

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Size matters in batteries. The bigger the electrode surface area more current can be drawn. A very simple example is that of ten 1.2 V pencil cells connected in series at home vs. a 12 V lead-acid battery. Which one can start a car? The lead-acid battery-although the voltage of both batteries is the same.

Not only does size matter, but the rate of electron transfer also matters in batteries. Poor "lead-acid" cell, despite its all negative environmental image, still has the fastest (I don't know the record) electron rate transfer to the electrodes, hence you can draw more current out of it.

So microbattery is not feasible for large sustainable currents. A cardiac pacemaker is also a very small power source but its out is also very low. You can search about electric power sources for space programs. They must be lightweight and reliable. If I remember correctly, each "kg" adds a million to the cost of launching.

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  • $\begingroup$ Thanks very much for the answer! I also wonder apart from lead-acid, what other materials have good rate of electron transfer? What are the best known ones in terms of this? $\endgroup$
    – user142857
    Commented Oct 15, 2021 at 22:11
  • $\begingroup$ I am not the downvoter, but I can spot a few misspellings/misstypes in your post you might address. Please take a second to review it. Your answers are generally well received due to their content but a little copyediting before posting would be appreciated. $\endgroup$
    – Buck Thorn ♦
    Commented Oct 16, 2021 at 5:25
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    $\begingroup$ You might also address the OP's original query, which is repeated here in the comments. As it stands, you've not touched on all points, which detracts from your answer. $\endgroup$
    – Todd Minehardt
    Commented Oct 16, 2021 at 15:53
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    $\begingroup$ I agree with Todd. You can find plenty of plots showing the tradeoff between energy and power density, but few explanations. Also, I came across at least one somewhat old ref suggesting that this can be overcome in small devices, and that such a device, scaled up to be as large as a phone battery, could start a car. $\endgroup$
    – Buck Thorn ♦
    Commented Oct 16, 2021 at 16:34
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    $\begingroup$ There is a very nice 1200 paged handbook called Handbook Of Batteries by David Linden, Thomas B. Reddy. If the OP is serious about this research, he should get it. $\endgroup$
    – ACR
    Commented Oct 16, 2021 at 16:34

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