Why do batteries loose omph when it gets cold?

[TSN79]

Why do batteries loose "omph" when it gets cold?

Simple question really;
It's well known that car batteries (and others) don't work as well when the temperature approaches -20C. I'm just wondering why? What's the physical reason? Also, if you bring the battery back to room temperature, will it regain its "strenght" to where it was before it got cold?

 

[mgb_phys]

Chemical reactions slow down at lower temperatures.
It also increases the internal resistance so although the amount of energy stored in the battery is the same - the amount you can get out drops.

Providing that the electrolyte doesn't freeze and burst the battery then lead acid typically recover, in fact storing them at low temperatures reduces the self discharge rate.

 

[charng]

There are a few reasons why batteries lose their "omph" or strength when it gets cold. First, the chemical reactions that occur within the battery to produce electricity slow down in colder temperatures. This is due to the decrease in the mobility of ions and electrons, which are essential for the flow of electricity.

Additionally, the colder temperature causes the battery's internal resistance to increase, making it harder for the battery to deliver the necessary power. This is because the electrolyte, which is the medium for the chemical reactions, becomes less conductive at lower temperatures.

Furthermore, the cold weather can also affect the materials used in the battery. For example, the metal plates inside a battery can contract in colder temperatures, reducing their surface area and therefore decreasing the amount of current that can flow through them.

As for whether a battery can regain its strength when brought back to room temperature, it depends on the extent of the damage caused by the cold. If the battery was only temporarily affected by the cold and not damaged, it should regain its strength once it warms up. However, if the cold caused permanent damage to the battery, it may not be able to fully regain its strength. It is important to properly maintain and store batteries in optimal conditions to prevent any potential damage from the cold.