Greater energy and more complex integrations demand battery safety is the first consideration
Protection Circuit Module (PCM)
Offering full protection against Over Charge voltage, Over Discharge Voltage, Over Discharge Current, Over Charge Current, Short Circuit Current and Cell Imbalance, a Lithium-ion PCM offers a comprehensive range of safety features to ensure the safety and long life of a connected battery pack and cells. The PCM provides primary battery safety mechanism for all Lithium-ion builds and must be selected carefully in order to produce a battery pack capable of complying with the stringent safety, transportation and handling regulations.
Battery Pack Thermistor
To ensure safety, maximum performance and life from a battery pack, cells should only be charged and discharge within their design specification. Cell temperature can be monitored at all times either by the host equipment or the charger through the use of an internal battery pack thermistor.
Resettable fuses offer dependable secondary protection for overcurrent and overtemperature conditions in both the charge and discharge direction for all battery chemistries. Being self-resetting these devices are highly suitable for battery applications in extreme and difficult to access environments where reliability and continual service-free function is the absolute priority.
PolySwitch PPTC (Polymeric Positive Temperature Coefficient)
A Polyswitch is a non-linear thermistor designed to remain in a low resistance state during normal operation and a high resistance ‘fused’ latch state during over-current conditions. Normal battery function is automatically restored with the removal of the charge or load condition. Polyswitches additionally offer a form of over-temperature protection preventing the battery from being used if a dangerous battery over-temperature is detected. –Unlike fuses, Polyswitches will pass a very small hold current to remain in their ‘fused’ state.
Thermostats and Thermal Cut-Outs
A resistive-bimetallic device capable of physically breaking the discharge/charge circuit at a specified temperature by bending a thin metallic strip. Normal battery function is automatically restored when the temperature falls back within the operating window allowing the bimetallic strip to cool down. A Bimetallic element manufactured from a high resistance materials will cause self-heating within the device itself during high current flow, hence offering both overtemperature and overcurrent protection within a single reliable maintenance free component.
Non-Resettable Current Fuse
Non-Resettable current fuses offer fast acting high current, high voltage blocking, secondary protection for over-current conditions in both the charge and discharge direction for all battery chemistries. Non-resettable fuses are broadly said to be unaffected by temperature and hence offer no protection against battery over-temperature conditions. Being capable of blocking very high voltages in their fused state and capable of passing high currents with very little resistance or self heating, non-resettable current fuses are highly suitable for larger battery pack designs where rapid protection is critical.
Non-Resettable Temperature Fuse
Non-Resettable Temperature fuses offer low resistance highly sensitive direct over-temperature protection for all battery chemistries. Being capable of blocking very high voltages in their fused state and capable of passing high currents with very little added series resistance, non-resettable temperature fuses are good choice for the final layer of safety in larger battery pack designs where thermal protection is critical or where cell warming techniques are employed.