EV FUSE

The working principle of the fuse is very simple: we know that when a short circuit occurs in the circuit, the instantaneous current will be very high, and the conductive wire will be heated at the same time. If there is no fuse in the circuit to protect it, it is likely to burn out the electrical equipment.

In order to protect the electrical equipment from being accidentally short-circuited and burnt out, people have invented fuses and connected them in series to the circuit. The key part is a special metal wire or conductive sheet with a low melting point. The high current will cause the conductive part of the fuse to heat up, reach the melting point, melt, disconnect and lose the link to cut off the current. Thereby protecting the electrical equipment. The fuse big insurance housekeeper should have heard of it, and that is the fuse.

In the high-voltage distribution box of an electric vehicle, the output terminal is mainly connected to the auxiliary power supply system of the vehicle, and the inside of the distribution box generally includes an electric heating fan branch, an air-conditioning compressor branch, a DC/DC branch and a charger branch. . These four branches, each branch needs to install line protection fuse, the purpose is to cut off the power protection circuit in time when each load is short-circuited, and avoid vehicle fire. With the comprehensive advantages of small size, good shock resistance and low price, fuses have been widely recognized and used in large quantities, and have become the main components recognized at home and abroad as the short-circuit protection of electric vehicles.

The on-board lithium batteries, energy storage capacitors, motors, converters and electronic control circuits in new energy vehicles are all DC systems, and DC-type fuses are required for short-circuit protection to ensure safe and reliable normal operation and super-powerful operation. Short circuit breaking effect. According to the current fuses used in the electric vehicle industry, the maximum system voltage of most models is generally below 700VDC, and there are also a few models that are slightly higher than this voltage, so the fuses used for battery protection can be divided into two types: 500VDC and 700VDC. Mainly, the current level is mostly 200A~630A.

The application fields of fuses are very wide, such as the popular photovoltaic market in the past few years. This article mainly talks about the application in new energy vehicles and their supporting industries, such as DC charging piles, DC, plumbing PTC chargers, air heating PTC, power batteries, maintenance switches, high-voltage boxes, electric air conditioners, etc. The place.