What is Pyrofuse

The working principle of traditional fuses is thermal melting, where the fuse element heats up and melts

due to Joule heating when the current overloads, thereby breaking the circuit. This mechanism can be

reliably applied in low-voltage, low-current scenarios, but in high-voltage, high-current circuits, the

following shortcomings generally exist: slow response speed, with melting times typically ranging from

milliseconds to seconds; insufficient segmenting capability, making it difficult to extinguish high-voltage

arcs; and passive triggering, which cannot be linked to the vehicle’s safety system.

Pyrofuse, also known as Pyroswitch or Pyrotechnical Safety Switches (PSS), is referred to in Chinese as

explosion fuse, high-temperature fuse, pyrotechnic control switch, instantaneous circuit breaker, or

pyrotechnic fuse. This is an irreversible mechanical switch fuse primarily used in the high-voltage systems

of new energy vehicles. By utilizing a pyrotechnic triggering mechanism, it rapidly cuts off the circuit in

emergency situations to prevent electrical hazards such as fires and short circuits. Unlike traditional fuses

that rely on thermal effects, pyrotechnic fuses trigger the pyrotechnic device via signals, enabling faster

and more reliable circuit protection