Innovative device protects portables from arcing

Innovative device protects portables from arcing

The award-winning MHP30-36 from TE Circuit Protection is a metal hybrid polymeric positive temperature coefficient (PPTC) device that combines a bimetal protector in parallel with a PPTC device. It offers 30-A hold current and an initial resistance of less than 2 mΩ, and provides resettable overcurrent and over-temperature protection. The company saw a need for the PPTC for Li-ion technology especially because Li-ion requires a higher level of circuit protection since it has a higher power level than NiCd and lead-acid technologies. The company also saw that there were limited battery protection options available on the market at ratings above 30-A hold current and 30 Vdc.

The device combines a bimetal protector and a PolySwitch PPTC device. This combination incorporates the best features of a bimetal breaker and PPTC and allows the PPTC technology to be used in higher current applications. The MHP device can be useful in dc-rated designs that require arc-suppressed, latched, high-current protection. The resettable MHP30-36 device provides excellent arc suppression characteristics compared to standard breaker devices that must limit the number of switching cycles since arcing between contacts may damage them. It can be used for portable or motive applications including cordless power tools, medical devices and e-bikes.

TE Circuit Protection members who helped develop the MHP30-36 PPTC protection device. (L~R: Arata Tanaka, Dave Martin, Katsuaki Suzuki, Ty Bowman)

The design team had six members and 11 key contributors who needed about three years to develop the award-winning technology and it certainly wasn’t without its challenges. The team had to come up with a method to achieve proper contact balance for the double make/ double break design. Additionally, because every battery pack design is custom-made and the protection requirements vary by end customer and application, optimizing the device specifications to cover a broad number of end customer requirements, was a challenge. Customer interest in the core MHP technology has led to some extensions of the technology to create three-terminal MHP devices that enable external electronic activation of the device via a signal line.

Paul O’Shea