Hello!

For a project I am looking for very small lipo batteries. <3mm thickness, ideally around 2mm. Obviously they can be thinner. Capacity about 70mAh, bigger is better.

In terms of the other dimensions, one can be about 4cm (that is below 1 2/3 inches), and the other as small as possible as well, I would be fine with 3cm (1,2 inches).

I'm not sure yet about the peak current usage as I am still in the planning stages. I would assume not more than 100mA, some of it I can surely buffer with a capacitor as the main load will be a PWM signal with 50% duty cycle.

I know these are very specific dimensions, especially the thickness constraints, I'd love to explain.

I'm designing a wearable placed inside of a semi-flexible casing. It needs to be as small as possible, and I'm planning on using the circuit board as an outer shell surrounding the battery, giving it some mechanical protection, hence my requirement (among other reasons) for the battery to be quite thin.

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I'm not sure where to get batteries like these. I'm having issues finding sellers shipping to Germany at a reasonable price, moreover they're obviously batteries so getting them from a reputable source and of decent quality is important.

I also thought about going about this a different way and trying to find replacement batteries for a pre-existing product (i.e. smartwatches and other wearables) which happen to fit my requirement, but no luck so far as they often don't even come with dimensions in the product descriptions, or they are unfortunately too expensive or too thick.

Maybe lithium coin cells could also be an option?

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Maybe one of you can point me in the right direction. Thank you!