Energy storage pre-charge resistor

How can a pre-charge resistor help a battery management system?

By incorporating a pre-charge resistor and forming a pre-charge loop in the battery management system of electric vehicles, the voltage stress on components in the control system can be greatly reduced, the impact current in the circuit can be lowered, so the damage to relays can be prevented, ensuring the safe use of the power battery.

How much power does a precharge resistor dissipate?

The power dissipated by the precharge resistor during precharge is that energy over the precharge time. For example, with a precharge time of 500 ms: P = V^2 / R = 100 ^2 / 10 = 1000 W! Now, over the long term, the precharge resistor will not need to dissipate any significant power (it will not get hot).

How do you choose a precharge resistor?

The resistance of the precharge resistor is chosen based on the capacity of the load and the desired precharge time. The precharge surge current reaches 1/e of its initial value after a time of: The precharge resistor needs to dissipate as much energy as the energy stored in the load's input capacitors.

Why is my pre-charge resistor failing?

The pre-charge resistor failing due to over-heating then needs to be at least considered. In a battery the contactors are a switch that can be operated by the control system. They are essentially a relay. These contactors are designed to be able to break (switch off) the circuit under full load (maximum current and at maximum system voltage).

Where is the precharge resistor located?

In the typical precharge circuit, the precharge resistor is on the positive terminal of the battery, though it could just as easily be on the negative terminal. While you are free to use any designators you wish, the ones in this schematic (R1, K2, K2 and K3) appear to be industry standard, so you are encouraged to use them as well.

What is a power resistor used for?

The power resistor is widely used in PCB and cabinets for current limitation, voltage division, and circuit protection. TE provides a wide resistor portfolio for the BESS market.