Testing system for safe operating window of lithium-ion battery in squeezed state and testing method thereof

A testing system for a safe operating window of a lithium-ion battery in a squeezed state, the testing system comprising:

• a mechanical loading device, wherein the mechanical loading device comprises a base, an extrusion punch, a clamping claw plate, and a pressure applying mechanism arranged on the base, the clamping claw plate is configured to clamp the extrusion punch, and the pressure applying mechanism is configured to apply a pressure to the lithium-ion battery through the extrusion punch;
• a heating device, wherein the heating device comprises a heating plate and a proportional-integral-derivative (PID) temperature controller, the PID temperature controller is connected to the heating plate by a wire, the heating plate is located on the base, and the lithium-ion battery is placed on the heating plate;
• a lithium-ion battery tester, wherein the lithium-ion battery tester is connected to positive and negative electrodes of the lithium-ion battery by wires;
• and
• a measuring device, wherein the measuring device comprises a first thermocouple configured to measure a temperature of the lithium-ion battery, a laser distance sensor configured to measure a compressional deformation of the lithium-ion battery, a pressure sensor configured to measure a pressure value experienced by the lithium-ion battery, a data acquisition device, and a computer;
• the first thermocouple, the laser distance sensor, and the pressure sensor are all connected to the data acquisition device by wires, and the lithium-ion battery tester and the data acquisition device are connected to the computer by wires,
• wherein the clamping claw plate comprises a first half and a second half separated from each other, the first half and the second half form an inverted U-shaped slot after being fitted together, inner walls of two sides of the inverted U-shaped slot are each provided with a protrusion;
• the extrusion punch is provided with grooves, an upper part of the extrusion punch is embedded in the inverted U-shaped slot, and the protrusion is engaged in a respective one of the grooves,
• the first half and the second half are provided with connecting through holes, respectively, and a bolt is passed through the connecting through holes and then connected to a nut to fasten the extrusion punch and the clamping claw plate together,
• in order to test the safe operating window of the lithium-ion battery in the squeezed state with a fixed mechanical pressure, the pressure applying mechanism comprises a weight, a tray, a main shaft, at least one limit sleeve, and a support,
• the support is fixedly connected to the base, the limit sleeve is arranged on the support, the main shaft is movably connected to the support by the limit sleeve, the main shaft is arranged vertically, the main shaft is movable up and down along the support, an upper end of the main shaft is connected to the tray, and the weight is placed in the tray;
• and a lower end of the main shaft and the first half of the clamping claw plate are fixedly connected to each other and are integrally formed.