ARLINGTON HEIGHTS, ILLINOIS, USA, Monday, November 30, 2009: Hill Tech Sales, a leader in components for Electrical Power Conversion today posted information on Lithium-ion battery pre-charge resistors.
Large scale Lithium-ion battery technologies present a new challenge regarding enormous inrush current requirements when used in Electrical Vehicle (EV) applications. Ceramic composite resistors provide a reliable high energy resistor solution for these pre-charge events.
Modern DC converters use input capacitors as part of their power converters’ topology. When used with a Lithium-ion battery, huge inrush currents can occur as the capacitors are charged up to the battery voltage. The inrush becomes extremely difficult to handle when using large batteries with a low source resistance, and substantial capacitance values. Combined with little and/or no charge on the capacitors, inrush currents peaking over 1000 Amperes can easily occur.
A typical solution is to use a high energy resistor in a DC pre-charge circuit, to limit inrush current without limiting the operating current. Ceramic composite resistors are made for these applications. Unlike wire wound resistors or metal film resistors where only a metal conductor is absorbing the energy, the composite resistors’ entire mass is absorbing the energy yielding incredibly high impulse energy capacity. Reliability and robustness is also greatly increased since there is no “thin wire” acting as a conducting medium.
Typically a pre-charge resistor is used between a battery and the load to:
- Prevent damaging the input capacitors.
- Protect battery cells.
- Stop the main fuse from blowing during the inrush current event.
- Prevent damaging the contactors in the circuit.
Sizes of high energy resistors range from a few kilo-joules to mega-joules.
For more questions on this article contact:
High Energy Resistor Specialist
Hill Technical Sales
216 West Campus Drive
Arlington Heights, IL 60004
Tel: +1- 847-255-4400 ext 11
You may also visit: http://www.hilltech.com/