EV (Electric Vehicle) batteries store power as DC (Direct Current).
Understanding Battery Power
Electric vehicle batteries, like most battery-powered devices, use direct current (DC). This means the electrical current flows in one direction. This is in contrast to alternating current (AC), where the current direction reverses periodically.
Why DC for Batteries?
- Direct Storage: Batteries inherently store energy in a DC form. This aligns with the chemical reactions within the battery cells that produce a flow of electrons in one direction.
- Efficiency: DC power allows for a more efficient conversion and storage of electricity in batteries.
The Role of Converters
The power that comes from the electrical grid is always AC, however, batteries store power as DC. So, when you charge your EV from the grid (AC power), a converter within the charging system changes the AC to DC so that the battery can store it. Most electronic devices also have this converter built into their plugs.
| Feature | AC (Alternating Current) | DC (Direct Current) |
|---|---|---|
| Current Flow | Changes direction periodically | Flows in one direction |
| Source | Power grid, generators, some inverters | Batteries, solar panels, some power supplies |
| Use in EVs | Used when charging through grid, not for battery storage | Used for battery storage, powering the motor |
Key Takeaway
Although electricity is transmitted via the power grid as AC, the energy is stored in EV batteries as DC. This is because batteries are inherently designed to operate with and store DC power. Therefore, a converter is needed to change AC to DC before the electricity enters the battery.
