The rapidly expanding market for high-rate discharge lithium-ion (Li-ion) batteries used in applications such as cordless power tools, electric bikes, electric cars, electric vehicles (EV) and battery back-up power supplies (UPS, inverter) has created the need for cost-effective circuit protection devices. Tyco Electronics has developed a new hybrid device that connects a bimetal protector in parallel with a PPTC (polymeric positive temperature coeffi cient) device. The resulting Metal Hybrid PPTC (MHP) device helps provide resettable overcurrent protection while also utilizing the low resistance of the PPTC device to help prevent arcing in the bimetal protector at higher currents.

Benefits of MHP Battery Protection Device

  • Fills market need for battery protection devices rated above 30A and 30VDC
  • Provides resettable overcurrent and short circuit protection in Li-ion battery packs
  • Helps protect Li-ion cells from damage due to abnormal high currents that could cause heat damage and lead to premature cell end of life and potential fi eld returns
  • Arc suppression: Current shunts to the PPTC due to its low resistance helping to suppress arcing all while helping protect the contacts from damage or welding shut
  • Double make/double break contact design allows for a high current rating in a smaller device package

Applications of MHP Battery Protection Device

  • Li-ion battery packs for high-rate-discharge applications
  • Cordless power tools
  • Electric vehicles (cars and bikes)
  • Back-up power supplies (UPS)
  • Back-up power for medical devices
  • Electric Motor protection