Because of excessive car models, product development cycle is too short and other factors, the safety hazards of electric buses are greater, need to focus on supervision. When asked about the three yuan to suspend the use of the battery when there is no release schedule, Ouyang Minggao said the relevant departments are currently working on the development of relevant safety standards.
Security is a positive feedback concept, rather than our emphasis on security, so we feel that the electric car is not safe. Electric vehicles still need to continue to innovate the emerging industries, both the need for social tolerance, but also need to reduce vulnerability, not because of the one or two security incidents, it will scare consumers." Hundred people in charge of the August 12th hundred people will be in the summer forum and electric vehicle safety report media conference said.
Battery safety is related to temperature. Other parts of the battery and engine, as the temperature rises to a certain temperature, the battery will start to produce side effects, side effects of chain will form the battery heat, to a certain extent, will cause internal short circuit breakdown, diaphragm electrolyte combustion, the temperature rises rapidly, the formation of thermal runaway, to reach the highest temperature will form a smoke, fire or explosion.
Note that the three features: one is the temperature "spontaneous onset temperature"; two is the "starting temperature" thermal runaway, such as short circuit, large scale combustion; three is the "thermal runaway" highest temperature, such as the internal core temperature reaches 900 degrees or even close to 1000 degrees.
The battery can only be in a certain temperature range to work properly, the temperature is not high, low or not. In low temperature environment, the battery capacity can not put out, also can not charge, this is because the battery polarization. In short, the battery cold, if the battery temperature is too low, it will not work properly. Under high temperature environment, the battery can not work properly, the normal operating range is within 45 degrees, if the temperature reaches 100 to 90 degrees, the problem arises. The battery will cause a series of "self generated thermal reactions."
When the temperature reached 150-250 degrees, the thermal runaway will occur, such as the breakdown of the diaphragm, electrolyte combustion, the maximum can reach more than 900 degrees celsius.
Lithium battery due to the characteristics of the existence of security risks, but does not mean that the electric car is not safe. Therefore, in order to prevent the battery from heat out of control, the need for strict thermal management, from the heating, cooling, heat insulation in three areas to keep the battery temperature is always maintained within the normal range.
The so-called cooling, in short, is through the cooling system to heat, the system design is very complex, there is air cooling, water cooling, etc.. Without heating in winter when the temperature is low, but the heating system is a relatively difficult; the insulation is when a battery thermal runaway situation, not serious to insulation, to prevent as a fever like firecrackers, the first heat conduction from battery to another battery, form a chain reaction.
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