Spraying system of a battery pack, comprising: a spraying pipeline configured to circulate a fire-fighting fluid, the spraying pipeline being capable of forming an opening after being heated; and a first gas storage portion configured to store a compressed gas, wherein the compressed gas in the first gas storage portion is capable of driving the fire-fighting fluid in the spraying pipeline to be discharged under the action of gas pressure; the spraying system further comprising a liquid storage portion, wherein the compressed gas in the first gas storage portion is further capable of driving the fire-fighting fluid in the liquid storage portion to enter the spraying pipeline under the action of gas pressure; the spraying system further comprising: a fire-fighting fluid storage device, the fire-fighting fluid storage device comprising: a tank having an inner cavity; and a partition member located in the inner cavity of the tank, the partition member dividing the tank into the liquid storage portion and the first gas storage portion, wherein the liquid storage portion has a fluid outlet, the fluid outlet being in communication with the spraying pipeline, and the first gas storage portion is configured to have a fluid inlet; and the partition member is capable of driving the fire-fighting fluid in the liquid storage portion to move toward the fluid outlet under the action of the compressed gas in the first gas storage portion; when thermal runaway occurs in a unit battery of the battery pack, the spraying pipeline is capable of forming an opening, and the fire-fighting fluid in the spraying pipeline is discharged from the opening, such that part of the fire-fighting fluid in the liquid storage portion enters the spraying pipeline, so that the amount of the fire-fighting fluid in the liquid storage portion is reduced, the pressure decreases, the compressed gas in the first gas storage portion drives the partition member to move toward the liquid storage portion and then drives the fire-fighting fluid in the liquid storage portion to enter the spraying pipeline, and the fire-fighting fluid is sprayed from the opening of the spraying pipeline to prevent thermal diffusion. a spraying pipeline configured to circulate a fire-fighting fluid, the spraying pipeline being capable of forming an opening after being heated; and a first gas storage portion configured to store a compressed gas, wherein the compressed gas in the first gas storage portion is capable of driving the fire-fighting fluid in the spraying pipeline to be discharged under the action of gas pressure; the spraying system further comprising a liquid storage portion, wherein the compressed gas in the first gas storage portion is further capable of driving the fire-fighting fluid in the liquid storage portion to enter the spraying pipeline under the action of gas pressure; the spraying system further comprising: a fire-fighting fluid storage device, the fire-fighting fluid storage device comprising: a tank having an inner cavity; and a partition member located in the inner cavity of the tank, the partition member dividing the tank into the liquid storage portion and the first gas storage portion, a tank having an inner cavity; and a partition member located in the inner cavity of the tank, the partition member dividing the tank into the liquid storage portion and the first gas storage portion, wherein the liquid storage portion has a fluid outlet, the fluid outlet being in communication with the spraying pipeline, and the first gas storage portion is configured to have a fluid inlet; and the partition member is capable of driving the fire-fighting fluid in the liquid storage portion to move toward the fluid outlet under the action of the compressed gas in the first gas storage portion; when thermal runaway occurs in a unit battery of the battery pack, the spraying pipeline is capable of forming an opening, and the fire-fighting fluid in the spraying pipeline is discharged from the opening, such that part of the fire-fighting fluid in the liquid storage portion enters the spraying pipeline, so that the amount of the fire-fighting fluid in the liquid storage portion is reduced, the pressure decreases, the compressed gas in the first gas storage portion drives the partition member to move toward the liquid storage portion and then drives the fire-fighting fluid in the liquid storage portion to enter the spraying pipeline, and the fire-fighting fluid is sprayed from the opening of the spraying pipeline to prevent thermal diffusion.