The invention discloses an automatic fire extinguishing device for automatically sensing
thermal runaway of a battery of a
new energy vehicle. The automatic fire extinguishing device comprises a base, a control box, a fire
blanket body, a release
assembly and a
fire detection probe. The whole base is of a frame-shaped structure and is fixed to a preset position of a vehicle, and a
fixed joint strip is arranged on the top face of the base. The fire
blanket body is rectangular and comprises a base cloth layer, a
coating and a heat insulation filling layer, a positioning strip is arranged on the top face, and heavy drooping blocks are arranged on the two sides. The release
assembly comprises a fixed seat, a splicing seat, an
electromagnet, a melt strip and a joint block, and the
electromagnet adsorbs the heavy drooping block through magnetic force so as to store the fire
blanket; the
fire behavior detection probe comprises a spectrum sensor, a
smoke sensor and an
infrared temperature sensor and is used for monitoring
fire behavior in real time. When a fire occurs, the control box receives a detection
signal to
cut off a power supply of the
electromagnet, or the melt strip melts at a high temperature to actively
cut off power, so that the weight drop block drops to pull the fire blanket body to be completely unfolded and cover a fire area, and the fire is inhibited by blocking
oxygen.