The new MHP-SA device helps provide overcharge protection in large multi-cell battery packs and modules in which circuit protection devices interface with electronics as part of a sophisticated battery management system. The MHP-SA device’s Smart Activation design feature accomplishes this via a third terminal signal line that enables external activation.
In a typical scenario, an IC monitors the battery system’s temperature, current and voltage and, if an abnormality is detected, it switches on a FET and activates the heater element (PPTC) of the MHP-SA device to heat the bimetal. The bimetal contacts then open and cut contact to the main line. The first in a series of planned devices, the new MHP-SA50-400-M5 device has a 50A/400VDC maximum rating and its hold current is 50A on the main line. The device can be activated electronically with as little as 3A via the signal line.
MHP Technology utilizes a hybrid circuit protection approach, combining a bimetal protector in parallel with a polymeric positive temperature coefficient (PPTC) device. Resettable MHP technology offers excellent arc suppression characteristics and also offers a smaller size and thinner form factor compared to larger DC fuses or other protection devices.
The MHP-SA device helps save design costs due to its ability to employ a low-power switch to open the main line, enabling lower-cost FETs to be installed. And because the MHP-SA device is resettable there is no need to overrate for inrush currents. In some cases, designers can replace larger, higher-cost DC fuses with an MHP-SA device.
“Few protection solutions address high-rate-discharge battery applications, and traditional circuit protection techniques tend to be large, complex and/or expensive,” said Ty Bowman, TE Circuit Protection Global Battery Market Manager. “The MHP-SA device offers design benefits in multi-cell battery packs that conventional circuit protection approaches are unable to deliver. The MHP-SA device provides a rugged, resettable overcharge protection solution that offers battery pack designers and manufacturers a way to optimize space, reduce cost, enhance safety and help meet future battery safety requirements.”
TE Circuit Protection
800-227-7040; www.circuitprotection.com