An electric vehicle (EV) refers to any vehicle powered by batteries, including pure electric and hybrid models. The electrical systems in these vehicles operate at high voltages, typically between 100V and 1500V, and the battery pack can output fault currents of 3,000A or more. In the event of an overcharge, overload, or short-circuit fault, this abnormal current must be interrupted completely and swiftly to protect the entire system. Without effective protection, the consequences, such as a fire, can be catastrophic.
Due to the limited space within an EV, the only viable solution is a fast-acting fuse. Their combination of compact size, low cost, rapid response, and high breaking capacity has made them the universal choice for EV manufacturers worldwide. As the battery pack provides pure DC power, the overcurrent protection must be a current-limiting, fast-acting fuse filled with a quenching medium.
The Difference from Traditional Fuses
Fuses in conventional internal combustion engine vehicles, such as blade or bolt-down types, are designed for low-voltage systems (e.g., 32V, 48V). They are made of simple zinc or copper alloys and have no internal filler, making their construction very basic. This design is only adequate for protecting low-voltage electronics and small lead-acid batteries with low fault energy.
In contrast, the DC fuses used in new energy vehicles operate in high-voltage circuits from 100V to 1500V. Their primary role is to provide high-capacity breaking protection for the main battery system. Therefore, they must be constructed with a highly insulating, high-temperature resistant, and non-combustible body. The internal components must consist of a high-purity silver element and copper terminals for efficient power transfer. The body is filled with high-purity silica sand for arc quenching and is hermetically sealed with metal end caps to prevent any high-temperature arc from escaping.
Our filled, sealed fuses have an exceptional breaking capacity, capable of extinguishing a high-voltage arc and interrupting the current within 3-5 milliseconds (ms). This rapid action effectively protects the battery and vehicle systems, ensuring safety and reliability. For these fuses, materials that are high-temperature resistant, non-combustible, and high-strength are essential.
What are the Essential Capabilities of a New Energy EV Fuse?
1. High Vibration Resistance: EV fuses are typically installed on the chassis or in compartments where they are subjected to long-term vibration and shock from driving on various road conditions. The fuse must have a robust, high-strength overall structure capable of withstanding 5G acceleration and high-frequency vibrations.
2. High-Temperature & Fire Resistance: Electric vehicles operate in diverse climates, from extreme heat to freezing cold, and must function stably in all of them. The fuse materials must be chosen to handle both high and low temperatures. Critically, in the event of an accident, the fuse itself must be prevented from becoming a source of fire.
3. High Breaking Capacity & Durability: A high-voltage fuse must have a reliable service life. It needs to endure the forward and reverse currents from the battery and charging equipment over the long term, especially resisting current impulses in high-temperature environments without fatiguing the fuse element or causing premature failure. When an overload or overcurrent does occur, it must provide protection by interrupting the large fault current within 3-5 milliseconds.