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By 2020, China's electric vehicle fuse market will reach 2 billion US dollars.

working principle

On-board lithium batteries, energy storage capacitors, motors, converters and electronic control circuits are all DC systems, and all need DC type fuses for short-circuit protection to ensure safe and reliable normal operation and super-capable 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 a few models that are slightly higher than this voltage, so the fuses used for battery protection can be divided into two main types: 500VDC and 700VDC , The current level is mostly 200A~400A.

The lithium battery, energy storage capacitor, electric motor, converter and other important devices of electric vehicles are the most important and most expensive lithium battery system, and the path of the high-voltage cable in the car is very short, and it will take 1-2 minutes when a short-circuit failure occurs. (Ms) A strong surge current (above about 5-10KA) is formed inside, and the short-circuit current must be safely cut off in a very short instant to eliminate the damaging energy of the high-voltage arc, in order to effectively prevent the explosion and leakage of lithium batteries and semiconductor devices caused by rapid explosion And burns on fire.

In the high-voltage power distribution box of electric vehicles, the output terminal is mainly connected to the auxiliary power system of the automobile. Generally, the inside of the switch box will include the electric heating fan branch, the air-conditioning compressor branch, the DC/DC branch and the charger branch. Each of these 4 branches needs to install a line protection fuse, the purpose is to cut off the power protection circuit in time when each load is short-circuited, to avoid vehicle fires. The main power transmission route of electric vehicles with small size, good shock resistance and low price of fuses is: battery-converter-governor-electric motor, and the main fuse also has four protection functions.

Chart 1 Electric vehicle high-voltage circuit structure and fuse usage scenarios

At present, the DC fast fuse of aR semiconductor short-circuit protection, with its advantages of sensitive action, instant fusing, thorough arc extinguishing, etc., you can see the widest range of compatible power batteries, energy storage capacitors, motors, electronic devices and electronic control circuits. Protection needs should be the only optimization option that is currently universally applicable to all electric vehicles.

Industry Standard

According to the IEC 60269 fuse series standard (equivalent to the national standard GB/T 13539 series) formulated by the International Electrotechnical Commission, fuses are divided into special (GB/T 13539.2) on the basis of meeting the basic requirements (GB/T 13539.1). ), unskilled personnel (GB/T 13539.3) and semiconductor devices (GB/T13539.4) are three major types of use, which are divided into two categories: "full range short-circuit and short-circuit protection" and "local range short-circuit protection". Divided into backup characteristics (aM-short circuit protection), general purpose characteristics (gG-full range of industrial switching protection), quick-break characteristics (gR-semiconductor overload and short circuit protection, aR-semiconductor short circuit protection, gS-semiconductor circuit protection ), according to the speed difference of melting and breaking, 3 fusing characteristic levels are set.

In 2001, the National Standards Committee prepared to issue two national standards GB/T18384.2-2001 "Safety Requirements for Electric Vehicles" Part 2: Functional Safety and Failure Protection and GB/T17531-2005 "Safety Requirements for Hybrid Electric Vehicles" , To make relevant regulations for electric vehicle current protection.

The sixth "Quality Assurance Capability Requirements" of the "Standard Conditions for the Automotive Power Battery Industry" published in March 2015 stipulates that "Enterprises should pass the TS16949 quality system certification, and prepare and implement a production consistency control plan." The supplier-fuse manufacturer must also pass the TS16949 quality system certification. Without pre-certification, it will not be qualified as a qualified supplier, and the same quality of the fuse cannot be fully guaranteed.

Since the application of fuses in electric vehicles is still in its infancy, and the preparation of related industries and product standards is still in the exploratory stage, companies are also doing their own things in the context of lack of standards, trying to first enter the industry to establish an image of industry benchmarks and establish industry standards.

Market structure

The global circuit breaker and fuse market can be divided into low, medium and high voltage circuit breakers according to the installed voltage level. By the type of arc extinguishing medium, the circuit breaker market can be divided into air, vacuum, oil and SF6 circuit breakers. In addition, the low-voltage fuse market was the main contributor to the global circuit breaker market in 2014. This growth is mainly due to the huge and rapid development of the power grid.

According to a new market report "Circuit Breakers and Fuses-Global Industry Analysis, Scale, Share, Growth, Trends and Forecasts 2015-2021" released by high-level market research. In 2014, the market value of circuit breakers and fuses reached US$20.75 billion, and it is expected to reach US$31.11 billion by 2021. From 2015 to 2021, it will continue to grow at a compound annual rate of 6%.

From a geographical point of view, the circuit breaker and fuse market has been roughly divided into North America, Europe, Asia Pacific and Rest of the World (ROW). In 2014, North America was the largest contributor to the circuit breaker and fuse market. The North American market accounted for 34.8% of the total market share. The demand for circuit breakers and fuses in the North American market continues to rise, and it is likely to show substantial growth in the future.

In the end, from the technological exploration period to the initial stage of the fuse for electric vehicles in China, the products are gradually improved, and the market scale is gradually increasing. Yanzhong Consulting predicts that the fuse market for electric vehicles in China will reach 2 billion US dollars by 2020. (For detailed calculations, please refer to the "2016-2020 China Electric Vehicle Fuse Industry Investment Value Report" published by Yanzhong Consulting)

Main production companies

The price of DC high-voltage fuses for electric vehicles is slightly higher, and it is necessary to prohibit abnormal fusing of the fuses while being able to effectively protect the circuits of each system. In the field of DC high-voltage fast fuse, foreign companies have an advantage, and their accumulated technology and market advantages in the industrial and traditional automotive fields can quickly enter the field of electric vehicles. At present, most domestic car companies cooperate with foreign fuse companies.

The breaking capacity and protection characteristics of domestic DC fuses can meet IEC (International Electrotechnical Standardization Agency) or other general standards, and are not much different from imported products for the same purpose. Directives) certification, extreme condition testing, and automated production of series products, there is still a slight gap.

There are about 200 domestic companies specializing in the production of fuses, and less than 10 companies can supply electric vehicles in batches. The market is in its infancy. (For a detailed catalog of electric vehicle fuses, please refer to the "2016-2020 China Electric Vehicle Fuse Industry Survey Report" published by Yanzhong Consulting)

Chart 2 major fuse companies