We have had several requests to send out batteries internationally. There are few restrictions for us to do this. The first restriction is that the USPS does not allow us to ship ANY batteries not installed in equipment internationally.

622.5 Lithium and Lithium-ion Cells and Batteries General
Only lithium batteries under 622.51 and 622.52 that are properly installed in the equipment they operate may be sent internationally or to and from an APO, FPO, or DPO location, if permitted by the international destination country or APO, FPO, or DPO location. Lithium batteries that are packed with the equipment or lithium batteries sent separately from equipment are prohibited. Damaged or recalled batteries are prohibited and may not be mailed internationally under any circumstances.
This is why all international orders must be shipped by UPS. If you would like more information on the restrictions of shipping lithium batteries via the USPS, visit this reference page.