There is no standard for the related lithium battery electric heating film, and the standards for the construction industry and household appliances industry can be referred to. "JGJ 319-2013 Low Temperature Radiant Electric Heating Film Heating System Application Technical Regulations" and "JGT 286-2010 Low Temperature Radiant Electric Heating Film".

　　The classification of lithium battery electric heating film is divided according to the different electric heating film packaging materials, metal electric heating film, inorganic electric heating film (including carbon fiber electric heating film, ink electric heating film, etc.) and polymer electric heating film.

　　1. The metal electric heating film for lithium batteries is the first generation of thin film heating products. It uses vapor growth and other film forming techniques to attach conductive metal materials to the insulating material, and then cover the surface of the metal layer with a layer of insulating material to The metal layer is tightly wrapped inside to form a thin conductive film. After energization, the internal resistance of the metal heats up, forming an electric heating effect. Commonly used metal electric heating materials are copper and nickel. Different materials have different resistivities, different working voltages and heating powers. Different metal materials match different circuit designs to meet different user parameter requirements. The choice of different metal materials will also directly affect the cost of the electric heating film.

　　2. Inorganic electric heating film for lithium batteries. Inorganic refers to that the conductive material is inorganic, such as graphite, SiC, SiO2, conductive ink, carbon fiber and other conductive silicates. In the non-electromechanical heating film, the above-mentioned inorganic conductive material is mixed with the flame retardant, film-forming agent and other auxiliary materials, and then applied to the insulating substrate together to form a conductive film. When voltage is applied to both ends of the heating film, the conductive layer is actually a layer of semiconductor, which converts electrical energy into heat.

　　It should be noted that some inorganic conductive materials are brittle substances at room temperature. For example, SiO2 is the main component of glass. Such electric heating films need to be coated on rigid substrates and used as plate-shaped materials. The other part is flexible, such as conductive ink and carbon fiber. Inorganic materials are resistant to high temperatures, have a long life, and are easy to obtain. They are a class of heating equipment with excellent performance. However, the inability to bend and the difficulty in deformation are important reasons that limit the use of inorganic electric heating films. Flexible inorganic electric heating films can be more widely used.

　　3. The polymer electric heating film for lithium batteries is made by adding conductive particles to organic materials, processing them into thin film materials and then encapsulating them, or applying conductive materials on the insulating material substrate to make organic conductive films, and then use polymer insulating materials Package. Generally, the working temperature is not as high as inorganic electric heating film. In the category of organic electric heating films, silicone heating films, polyimide heating films, and PET heating films are all widely used categories.