Passive fire prevention protection device and method for power battery pack of electric vehicle

Abstract

The invention relates to a passive fire prevention protection device for a power battery pack of an electric vehicle. The passive fire prevention protection device comprises a power battery box, and an air vent valve, a cut-off valve, a pressure sensor and a control unit are arranged on the outer wall of the power battery box; the cut-off valve is connected with a vacuumizing device and a fire extinguishing agent device, and the power battery box maintains normal pressure inside; a quantitative macromolecular fire extinguishing agent is injected into the power battery box; the pressure sensor, the fire extinguishing agent device and the vacuumizing device are in signal connection with the control unit; and nitrogen, oxygen and carbon dioxide can penetrate through the air vent valve, while a macromolecular fire extinguishing agent gas can be obstructed. The safety protection measure for the power battery box of the electric vehicle has relatively high protection efficiency, specific energy of the power battery box is not reduced or is reduced as less as possible, and cost increase due to too high improvement of the IP grade of the battery box is avoided.

Description

Technical field [0001] The invention relates to a passive electric vehicle power battery pack protection device and method, and belongs to the technical field of power battery safety protection. Background technique [0002] In the process of application and promotion of new energy vehicles, a series of fire accidents occurred, casting a deep shadow on the development of new energy vehicles. According to the joint investigation of new energy vehicle fire accidents by public security, fire protection, vehicle management and other departments, it is found that the most accidents caused by vehicle spontaneous combustion, accounting for about 30% of the total number of fire accidents, shows that the spontaneous combustion caused by the power battery is new The primary cause of fire accidents in energy vehicles. [0003] Lithium battery fires have the characteristics of fast burning speed, high burning temperature, large differences in the burning of different systems, and a large amou...

AI Technical Summary

Problems solved by technology

[0004] (1) Low protection efficiency: the cooling system added in the battery box can only maintain the temperature in the battery box within a limited temperature range, and the thermal runaway of the battery is caused by various other factors, such as overcharging and collision, in addition to temperature. The system is unable to respond to triggers other than temperature;

[0005] (2) Poor protection ability: Enhancing the IP level of the battery box reduces the damage of external factors to the power battery to a certain extent, such as battery short circuit caused by water immersion, but it cannot eliminate disasters caused by the battery itself, such as overcharging , overheating, etc., and the cost is relatively high;

[0006] (3) Reduce the specific energy of the battery box: Filling the battery box with cooling materials can prevent or slow down the spread of thermal runaway of the power battery to a certain extent, but it increases the overall weight of the battery box and reduces the specific energy, which is different from that of electric vehicles. The technical requirements for the high specific energy of the automotive power battery box do not meet the requirements

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