Due to the development of electric vehicles, the problem is that the safety is not high. Peak BBS, the pinnacle of this organization, involves discussions on battery safety. Are lithium-ion batteries safe? Are electric vehicles safe? Many experts, in the two years from 2015 to 2016, especially in the automobile safety statistics released by Tesla (tesla), there was also a fire accident of domestically produced electric vehicles. These incidents are real, and some experts have concluded that China’s electric vehicles are unsafe, mainly because lithium-ion batteries are unsafe. The author's point of view is that safety measures are in place and electric vehicles are safe or unsafe. Are electric vehicles safe? Let’s analyze it for everyone below.Pressure connector.

This article is based on electric vehicles, on the basis of traditional vehicles, based on traditional vehicle safety measures, and on the premise of discussing the safety of electric vehicle technology and measures, to ensure its safety.

First, lithium-ion batteries are safe, what is the basis for green?

Inventor of lithium cobalt oxide, lithium manganate and lithium iron phosphate cathode materials, one of the founders of lithium-ion batteries, known as the "father" of the lithium battery industry, currently at the University of Texas at Austin, professor of the Department of Mechanical Engineering , Famous physicist, solid, 94-year-old John B. The foreword (John Banning, Guti’s husband) said, “Batteries will improve significantly in the next few years, including battery safety, price, energy density, service life, charge and discharge speed, etc.

The author understands that lithium-ion batteries will become safer in the next few years. Currently, lithium-ion batteries are safe, and the main foundations for green are:

(1) Compared with natural gas, lithium ion batteries and steam (diesel) oil will not ignite spontaneously or leak under natural (normal) conditions.

(2) Compared with lead-acid batteries, air and soil are not polluted under natural (normal) conditions.

Some experts have repeatedly emphasized that lithium-ion batteries are not safe and environmentally friendly. What is said is outside the "natural" conditions. For example, the quality of the battery is poor, the impact of external forces, and the conversion of electricity.

2. What is the main basis for the safety and environmental protection of electric vehicles in China?

(1) China's electric vehicles (new energy vehicles) stipulate that lithium-ion batteries must be used, and lead-acid batteries should not be used. Ordinary people already know and realize the use of lead-acid batteries.

(2) China's electric vehicle (new energy vehicle) stipulates that the model must be "pure electric drive". Lithium-ion battery is an epoch-making scientific invention. The type of electricity used by China's pure electric vehicles is synchronized with the progress of world science and technology.

(3) Electric vehicle manufacturers purchase lithium-ion power batteries. The manufacturer is an authorized manufacturer. The quality of its products is recognized by the government, and the government strictly controls battery manufacturers.

(4) China's electric vehicles use lithium-ion batteries, which are safe and environmentally friendly and are related to fuel (gas) vehicles.

3. The quality of China's power battery pack (safety) has been developing rapidly

Five years ago, the production scale of electric vehicles was small, and the production technology of complete vehicles was not yet mature. It focuses on the verification of engineering applications and is in the market verification stage. As shown in Figure 1, the battery pack is easy to integrate. The conductor extends the pole measurement point to the connector, and then connects to the LECU. The sampling line is long, the insertion point. The sampling line is messy, and there is a risk of short circuit if the wire is short-circuited.

Five years later, the production of electric vehicles began mass production, and the production technology of vehicles was basically mature and concentrated on the market launch stage. The modularity of parts is already very high. It is mainly composed of modules, BMU, PDU, water cooling system, MSD, structural parts, and high and low voltage wiring harnesses. Circuit boards are used to replace part of the sampling lines.

4. Introduced the quality (safety) technology of the main high voltage device of pure electric vehicles in China

The following is a schematic diagram of the high-voltage system of a pure electric vehicle. From the perspective of the schematic diagram, the main high-voltage devices include five high-voltage devices such as battery packs, high-voltage boxes, motors, DC/DC, and A/C. In terms of engineering, the quality of high-voltage equipment and the quality of interconnected components ensure the safety of electric vehicles. The continuous improvement of safety indicators is an eternal topic, specific issues and specific discussions.

Electric vehicles are usually equipped with power supply systems exceeding 300V and currents up to 200A. This is different from the 12/24v power system of a traditional car. The high voltage and current characteristics of electric vehicles endanger the safety and safety of high voltage components. As far as engineering is concerned, safety measures must be taken.

(1) High voltage distribution box safety technology

Anyone with company experience knows that every factory has a distribution room. Compared with a factory, a high-voltage distribution box is the factory's power distribution room. The function of the electric high voltage (PDU) is the power supply and signal transmission of the bridge high voltage equipment of the power battery, and it is ready to test the insulation fault of the high voltage system, open circuit fault, ground fault and high pressure, etc., which is the dynamic security of the vehicle system to ensure the safe transmission of power.

The high-voltage distribution box for pure electric vehicles has copper bars, circuit breakers, switches, contactors, soft switches, transformers, contactors, high-voltage relays, fuses, surge protectors, ammeters, voltmeters, transformers, switches, etc.

A) The basic purpose of designing a high-voltage distribution box is to ensure the safety of the car, the safety of the passengers and the safety of the car.

B)The necessity of designing and high-voltage distribution box, as an electric vehicle power battery energy storage equipment, from the size of the vehicle, the available space is very limited, and difficult, so this project, each contactor and integrated circuit fuse, on the one hand, can To meet the requirements of automobile driving, the second is convenient maintenance of the power battery system, reducing the need to disassemble the power battery pack.

C) Design requirements for high-voltage distribution boxes: compact layout, easy disassembly and assembly

D) The safety measure is to pay attention to the heat dissipation arrangement and improve the temperature focus.

The high-voltage components connected to the high-voltage distribution box include: power batteries, motor controllers, inverters, inverter power supplies, electric air conditioners, electric defrosting, charging bases, etc. Currently, cast aluminum alloy shells and connectors are generally used, and the protection level is IP67. The following trends are the development of small size, light weight and intelligence.

(2) Safety measures for high-voltage connectors and high-voltage wiring harnesses

Traditional connector equipment is difficult to meet its high current and high voltage requirements, and electric vehicle connectors must be high-power connection products. If it does not meet the requirements, the electric vehicle will cause a fire. Electric vehicle connectors must be automotive grade products, and industrial grade products do not meet the requirements. The main indicators are IP level, insulation level, low resistivity, anti-error, and locking function.

The metal wire is the connecting wire of copper wire, it is the connecting piece of copper wire, and it is the connecting piece of copper wire. In terms of function, there are two power lines, which carry the power of the actuator and the input signal of the transmitter. The power cord is divided into low-voltage wiring harness and high-voltage wiring harness.

Are electric vehicles safe? Safety technology and measures to solve the safety problems of electric vehicles? Safety technology and measures analysis of high-voltage devices

The high-voltage wiring harness is the cable between the electric vehicle connector and the connector, and is a key connector supporting the safe operation of the entire vehicle. One is the need for shielding, IP rating, and protection against overheating or burning. The environment for automobile use is harsh. If it does not meet the requirements, it is the most prone to spontaneous combustion.

Under the guidance of the iso 26262 international standard, China's electric vehicles will become more and more safe

ISO26262 is an international standard for the safety of electronic and electrical products in the automotive industry, such as electronic equipment, electronic equipment and programmable electronic equipment. ISO 26262 provides a life cycle (management, development, production, management, service, scrap) concept of automotive safety, and provides necessary support during these life cycle stages. This standard covers the entire development process of functional safety (including requirements planning, design, implementation, integration, verification, verification and configuration).

With the development of China’s new energy vehicles, manufacturers’ technological level is getting higher and higher, and the active implementation of ISO26262 international standards, China’s new energy vehicle safety ecosystem will be formed, and electric vehicle safety issues will gradually be eliminated.