What is PyroSwitch In Electric Vehicle, Working, Purpose, Advantages

March 3, 2021March 3, 2023 CS Electrical And Electronics

Hello guys, welcome back to my blog. In this article, I will discuss what is pyroswitch in electric vehicle, working of pyro fuse, purpose, advantages of using pyroswitch, and applications of pyrofuse.

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What is PyroSwitch In Electric Vehicle

Pyrotechnic Safety Switches (PSS) are activated by the airbag control device or BMS and securely and reliably break the circuit before a short-circuit may occur due to vehicle deformation. Our pyrotechnic-driven PSS disconnection systems employ airbag initiators that have been proven millions of times. The controller regularly checks the operation of the whole initiation circuit, including the line and initiator. Disconnection occurs without the use of any other external help after the initiating pulse.

All vehicle manufacturers prioritize security problems, and as a result, many sensors, fuses, and switches are installed in passenger cars and commercial vehicles to guarantee optimum protection for the automobile and its driver with their brands. DEKRA (Deutscher-Kraftfahrzeug-Überwachungs-Verein), a European vehicle inspection business, performed research on the effects of excessive vehicle body deformation following an accident. Following an examination of the facts, it was discovered that nearly 90% of road accidents result in a subsequent fire at speeds greater than 80 km/h and that the extreme deformation causes an earth fault on the thickest electrical conductor, the cable connecting the battery to the starter/generator.

The starter/generator cable is often left unprotected in wire harnesses, and in the case of a disaster, these unprotected or broken wires might provide short-circuit-like hazards for passengers and/or rescuers. Short-circuits can cause direct ignition, sparks, or arcs can cause smoldering fires as a result of the enormous heat development, but aside from these hot components in the engine compartment, the battery is the real culprit, as its stored electrical energy contributes to becoming the primary source of ignition in the car.

Development of PyroSwitch / Pyrofuse:

Disconnection systems and pyrotechnical safety battery connections have been certified as industry standards to further improve the automobile production line and prevent short circuits that might lead to a thermal event and burn.

A pyrofuse, also known as a pyrotechnic fuse, pyroswitch, or pyrotechnic switch, and commonly marked by (PSS- Pyrotechnic safety switches), is a low-cost, fast-acting protection switch that keeps you safe in the case of a crash, accident, or malfunction, and makes your trip safe.

What is Pyrofuse/Pyroswitch?

It’s a high-voltage positive battery terminal fuse that bursts and permanently disconnects the electrical connection to prevent a short circuit or fire in the event of an automobile accident or crash. The positive terminal of the battery is unplugged at the same time, causing the automobile to crash.

What does a Pyroswitch do?

It is triggered by the airbag control unit or the battery management system, and it disconnects the power source from the circuit board in milliseconds. It safely, reliably, swiftly, and efficiently disconnects the circuit and shuts down the power circulation before a short circuit may occur as a result of vehicle deformation. In other terms, it’s a battery disconnect switch that protects against short circuits produced by collisions.

It is used to separate the starter-generator cable from the electrical battery in many different electric and hybrid cars.

How does it work?

It has been demonstrated a million times. In pyrotechnic-driven PSS disconnection systems, airbag initiators are employed. The controller regularly checks the operation of the whole initiation circuit, including the line and initiator. Disconnection occurs without the use of any other external help after the initiating pulse.

Pyrotechnics speeds the separation piston by triggering it through the airbag ECU or the battery management system BMS. The bus bar is cut in less than 0.1 milliseconds, while the electrical connections are separated in less than 0.20 milliseconds. The plastic piston separates the bus bar ends, preventing an electric arcing effect and sparing the electrical components from additional damage.

Battery overload protection:

The automotive battery management system is far more demanding than other forms of battery management, and it needs constant monitoring of charging and discharging conditions. The major function of the BMS is to isolate the battery in the event of an emergency. Overload protection for the battery is achievable with a profuse, which not only prevents the battery from overheating but also prevents the battery from emptying since power is required for other vital operations.

Why is pyrofuse necessary?

The pyrofuse has several advantages in automotive applications.

Respond to the transportation needs of the District of Columbia
It’s a great opportunity to get rid of the high and fault currents.
Conduction losses are quite minimal.
The average market price is low.
A pyrofuse explosion can save a person’s life in just a few moments.

Applications:

Circuit breaker failures: Overcurrent protection against short circuits and faults.

Accidents: In the event of an automobile accident, the battery is isolated to protect against electric shocks and fire.

Overcharging: Protection against a fire caused by overcharging.

To summarize, The pyro-fuse cannot be reset and must be replaced, as its name indicates. It is connected to the contactor-relay coil circuit of the battery pack (low voltage side). When the automobile is switched off, these contactors ensure that the high voltage is securely separated in the traction pack battery box (or via the pyro fuse, after a crash).

Fortunately, the pyro-fuse is accessible by removing the driver’s seat and pulling back the carpet. An ohmmeter can then be used to check for an open circuit in the pyrofuse. However, the source of the pyro-fuse blowing (such as the collision sensors, which one would assume are the same ones that activate the airbags) must be determined and addressed as well.

This was about “What is PyroSwitch In Electric Vehicle“. I hope this article may help you all a lot. Thank you for reading.

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