Smallest rechargeable battery >= 10 mAh

[SiliconWizard]

What is, to your knowledge, currently the smallest rechargeable battery (any chemistry) with a capacity of approximately 10 to 20 mAh?

Note: I had a nominal voltage of ~ 3V-3.7V in mind, so 30 mWh to about 60 mWh would be a better figure, regardless of the actual nominal voltage (preferably >= 2V though.)

[tooki]

Panasonic makes a bunch of tiny rechargeable lithium batteries (various chemistries) in that ballpark, including their “pin type” cylindrical cells that are 3.6-4.7mm diameter, as well as a whole bevy of coil cells.

See the catalog here: https://energy.panasonic.com/dam/common/content/business/pdf/en/catalog/Catalog_EN_240701.pdf

[SiliconWizard]

I knew the pin type for primary batteries - often used for fishing lights, but not the Li-ion ones. Interesting, but I looked for a distributor and Mouser/Digikey came up. Apparently, they can't ship these references outside of the US. That bites. "Shipping restricted."

[Gribo]

There are Li-Polymer pouches -
Example, I don't know this specific product:
https://www.eemb.com/product-120
Edit: They also have rechargeable coin cells.

[langwadt]

not where you buy for something serious but shows they exist

https://www.aliexpress.com/item/1005005043931275.html
https://www.aliexpress.com/i/1005006075527607.html
https://www.ebay.co.uk/itm/276385021878

[thm_w]

Searching on aliexpress could give you some ideas:

- VL2020 20mAh: https://www.aliexpress.com/item/1005007540618404.html
- LIR2025: https://www.aliexpress.com/item/1005007089618866.html

- airpod type batteries:
https://www.aliexpress.com/item/1005005426420820.html
https://www.aliexpress.com/item/1005003481586785.html

edit: langwadt beat me to the airpods, I think those they posted are better quality.

[nali]

Panasonic makes a bunch of tiny rechargeable lithium batteries (various chemistries) in that ballpark, including their “pin type” cylindrical cells that are 3.6-4.7mm diameter, as well as a whole bevy of coil cells.

See the catalog here: https://energy.panasonic.com/dam/common/content/business/pdf/en/catalog/Catalog_EN_240701.pdf

Unfortunately a lot of Panasonic bettery products are for the OEM market, so you need a pretty high volume to get them interested (5 or even 6-digit quantities) 

[SteveThackery]

Some watches use rechargeable coin cells, in particular Casio, Seiko and Citizen.

There is a watch materials supplier in the UK called Cousins who stock a range.  For some reason they describe them as "capacitors", but I believe all the products are rechargeable batteries.  Perhaps you could find a suitable size and then check whether they really are batteries or capacitors.  Here are links to the pages on their site:

https://www.cousinsuk.com/product/citizen-capacitors

https://www.cousinsuk.com/product/seiko-capacitors

https://www.cousinsuk.com/product/special-capacitors-casio

[tooki]

I knew the pin type for primary batteries - often used for fishing lights, but not the Li-ion ones. Interesting, but I looked for a distributor and Mouser/Digikey came up. Apparently, they can't ship these references outside of the US. That bites. "Shipping restricted."

Yeah, lithium ion shipping is a problem.

But there must be some “native” European distributors that stock at least some of them.

[tooki]

Panasonic makes a bunch of tiny rechargeable lithium batteries (various chemistries) in that ballpark, including their “pin type” cylindrical cells that are 3.6-4.7mm diameter, as well as a whole bevy of coil cells.

See the catalog here: https://energy.panasonic.com/dam/common/content/business/pdf/en/catalog/Catalog_EN_240701.pdf

Unfortunately a lot of Panasonic bettery products are for the OEM market, so you need a pretty high volume to get them interested (5 or even 6-digit quantities) 

That is unfortunate. I guess it makes sense, but is annoying for the hobbyist or prototype builder!

[Someone]

I knew the pin type for primary batteries - often used for fishing lights, but not the Li-ion ones. Interesting, but I looked for a distributor and Mouser/Digikey came up. Apparently, they can't ship these references outside of the US. That bites. "Shipping restricted."

Yeah, lithium ion shipping is a problem.

But mysteriously they don't restrict the "hybrid" super capacitors. A 1/3 AAA size hits the OPs specifications. So about the same volumetric efficiency as a secondary *2032 cell.

[mikeselectricstuff]

Might help to say more about  your size constraint - is it volume, thickness, max dimension?

[jwet]

There was a hot company about ten years ago called Cymbet (Minneapolis) that made really tiny solid state batteries.  They got acquired or went bust but you can still find stuff online.  Most of their stuff was very, very small but they did do some larger.  In Chip Scale SMT packages similar to the TDK stuff from another poster.

[tom66]

Seiko Instruments make some of these.  I've used the MS621FE in the past.

https://www.sii.co.jp/en/me/datasheets/micro-battery/ms-rechargeable/ms920se/
https://www.sii.co.jp/en/me/datasheets/micro-battery/ms-rechargeable/ms621fe/

One thing to be aware of is their cycle life isn't great if you use 100% DoD.  It's around 80-100 cycles.  To get maximum longevity from them don't go below 50% DoD regularly.

[SiliconWizard]

not where you buy for something serious but shows they exist

https://www.aliexpress.com/item/1005005043931275.html
https://www.aliexpress.com/i/1005006075527607.html
https://www.ebay.co.uk/itm/276385021878

Ah the 45230 for airpods could be an alternative to the panasonic pin batteries. Not sure what the manufacturer is. I can find similar ones in large quantities on Alibaba, the vendor seems to be Eunicell.

[SiliconWizard]

So far, the company I've found that seems to have the most choice with very small batteries is Coincell Battery: https://www.coincell.cn/

[RoGeorge]

The smalles Li-Ion I have with protection board included is about the size of a nail in area, and about 5mm thick, but I can not find right now to give the exact size/part number/mAh.

Could be a 501017 or so

https://topwayenergy.en.made-in-china.com/product/xdzECiJGJukX/China-Small-Rechargeable-Lithium-Ion-Polymer-3-7V-60mAh-501017-Lipo-Battery-for-MP3.html

[I wanted a rude username]

The CTL1616 has the familiar CR1616 form factor, but rechargeable (2.3 V nominal, 18 mAh). Used in high-end Casio watches with solar charging tech. Probably too expensive for consumer stuff though ... hard to beat a pouch cell with no protection IC (you can put the IC on your PCB instead, more space-efficient that way).

[YTusername]

Check Everpower manufacture for small batteries. My past employer have used a small capacity one, 8-9mAh, but I can not share the part number.

http://www.htkjbattery.com/en/products/customized-shaped-battery/68.html

You can check as well the 21mAh battery used inside ORAA smart ring which is exposed here (https://youtu.be/BwA1hmSVgVY?si=eA35yvRZ4wjhfWtN&t=470) GREPOWER YE160728 from https://www.grepow.com/.