Device and method for detecting liquid absorption rate of lithium-ion battery separator

The invention discloses a device and a method for detecting a liquid absorption rate of a lithium-ion battery separator and belongs to the field of lithium-ion batteries. The detection device comprises a container for containing electrolyte, a tray for placing a separator sample, multiple capillary tubes penetrating through the tray surface, and an upper cover covering the container. Tube openings in the bottom ends of the capillary tubes stretch into the container, and tube openings in the top of the capillary tubes are slightly higher than the tray surface and push against the separator sample on the tray surface. The detection method comprises the following steps: intercepting the separator sample and weighing; putting the whole detection device in a weighing device, and reading weight reading; putting the separator sample on the tray surface of the tray, covering the container with the upper cover, and standing until the separator sample is completely infiltrated by electrolyte; taking out the completely infiltrated separator sample, covering the container with the upper cover, and reading weight reading; and calculating the liquid absorption rate of the separator sample. The detection device is simple in structure and low in cost, the detection method is easy to operate, and the detection result is small in error and high in accuracy.