Battery

Batteries are the energetic equivalent of Metal Store, as they give you extra Energy cap.

Main use
Batteries give you extra Energy storage, which means you'll have less floating Resources. They also let you store more energy to be able to build more expensive buildings, such as a Plasma Laser.

You need to be careful when placing those, as they blow up when they are destroyed. The damage is sufficient to blow up nearby batteries, meaning you can trigger a chain reaction if you put too much next to each other.

This has caused the deaths of many players, since some tend to build lots of batteries next to their Core, blowing it up when only 1 battery is destroyed.

Other info
In the old times, you could throw batteries at your teammates, and they would deal them damage as they crashed on the ground. This has been patched to prevent TK (Team Killing), and batteries no longer blow up if they touch the ground.

There are some spectacular chain reactions involving batteries and Cannons as those blow up as well when destroyed. Sometimes, a cannon crashes on the ground, triggering some batteries and blowing the player up.