As far as I am concerned： Diaphragm is located between the anode and the cathode, whose main fuction is to separate the positive and negative electrode active material, preventing short circuit caused by the contact of the two poles. In addition, in the electrochemical reaction, it can maintain the necessary electrolyte to form channel for icons to move. Diaphragm material is not conductive. Different types of batteries use different diaphragms.
The diaphragm of the battery mainly has two functions: 1. Insulating layer, can effectively prevent the contact of positive and negative electrodes to avoid internal short circuit 2. Semi permeable layer, it mainly exists in liquid batteries like the lithium ion battery, which can hold back molecules of relatively large volume and only allow charged ions of small volume to get through, improving the concentration difference in the vicinity of the positive and negative electrodes and in favor of the ion diffusion, so as to improve the storage efficiency of the battery.
The diaphragm is of course used to separate the anode materials from the and cathode materials. One side is copper foil coated with anode material, aluminum foil coated with cathode material. The positive and negative electrodes are separated by diaphragm, and anode and cathode material penetrate this diaphragm to discharge electricity. At present, they are all basically imported. it is said that homemade diaphragm is not very mature. which belongs to high polymer material. so, it should have a little scientific and technological content. . . The diaphragm is very important, because once it is punctured by impurities or hard objects , the battery will short out, which is likely to swell. namely the so-called flatulence.
