LiFePO4 batteries are a type of rechargeable battery that uses lithium iron phosphate as the cathode material. They are known for their high energy density, long cycle life, and safety. If you are looking for an OEM (Original Equipment Manufacturer) of LiFePO4 batteries, there are many companies that specialize in manufacturing these batteries. Some of the well-known LiFePO4 battery OEMs include:

CATL: a Chinese company that produces LiFePO4 batteries for a wide range of applications, including electric vehicles, energy storage systems, and more.

BYD: a Chinese company that produces LiFePO4 batteries for various applications, including electric vehicles, energy storage systems, and consumer electronics.

A123 Systems: an American company that produces LiFePO4 batteries for various applications, including electric vehicles, energy storage systems, and power tools.

Valence Technology: an American company that produces LiFePO4 batteries for various applications, including electric vehicles, energy storage systems, and marine applications.

Kokam: a South Korean company that produces LiFePO4 batteries for various applications, including aerospace, marine, and energy storage systems.

These are just a few examples of LiFePO4 battery OEMs, and there are many other companies that produce these batteries. It's important to do your research and find a reputable OEM that can provide high-quality LiFePO4 batteries that meet your specific needs.