Is there any battery which works in very cold weather, such as -40 degrees Celsius?

Yes, there are batteries available in the market that are specifically designed to work in very low temperatures, such as -40 degrees Celsius. These batteries are usually used in applications like outdoor equipment, military, aerospace, and automotive industries.

One example of such a battery is the Lithium Iron Phosphate (LiFePO4) battery, which has a very low internal resistance and can operate in temperatures as low as -40 degrees Celsius. Another example is the nickel-cadmium (NiCd) battery, which has good performance in cold temperatures and is often used in aviation and aerospace applications.

It's important to note that while these batteries can operate in very low temperatures, their performance may still be affected. For example, the capacity of the battery may be reduced by 20%-30%, and it may take longer to charge or discharge the battery.

There are several companies that produce batteries that can work in low temperatures, including:

1. Tesla: Tesla produces batteries for their electric vehicles that can operate in very low temperatures, thanks to their proprietary battery management system.

2. Pana-sonic: Pana-sonic is a supplier of batteries to Tesla, and they also produce their own batteries that can operate in low temperatures. They use a combination of advanced electrolyte chemistry and thermal management systems to keep their batteries working in cold weather.

3. LG Chem: LG Chem produces lithium-ion batteries for a variety of applications, including electric vehicles and energy storage systems. Their batteries are designed to operate in extreme temperatures, including temperatures as low as -40 degrees Celsius.

4. Codi Energy is a company who can provide solutions for low temperature working environment. Their batteries use advanced materials and design techniques to maintain their performance in cold weather.