Lithium ion battery diaphragm
By adopting a multi-layer structure in the lithium-ion battery separator, including a substrate layer, an adhesion coating, a high-temperature resistant coating and a corrosion-resistant layer, and designing multiple sets of concave surfaces in the protective part, the existing separator's inorganic binding force and insufficient overall strength are solved, and the high-temperature, corrosion resistance and electrolyte absorption capacity of the separator are improved.
Patent Information
- Application Number
- CN202421348606.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-13
- Publication Date
- 2025-06-06
- Estimated Expiration
- 2034-06-13
AI Technical Summary
The binding force between the inorganic substances and the separator itself of the existing lithium-ion battery separator is low, resulting in uneven surface of the separator and separation of the inorganic substances from the separator, affecting the battery performance, and increasing the porosity to ensure that the electrolyte passes through the electrolyte will reduce the overall strength and increase the chance of being pierced.
Lithium-ion battery separators are used, including substrate layer, adhesion coating, high-temperature resistant coating and corrosion-resistant layer. The substrate layer is made of PP or PE material, the adhesion coating is polyurethane resin adhesive, the high-temperature resistant coating is alumina, silicon oxide and other materials, and the corrosion-resistant layer is BaSO4 material. Multiple groups of concave surfaces are designed in the protective part to assist in the storage and absorption of electrolyte.
By increasing the bonding strength and toughness between the high-temperature resistant coating and the substrate layer, avoiding the phenomenon of diaphragm layer; improving the overall strength and heat resistance by using corrosion-resistant layers, reducing the risk of puncture deformation; concave design assists in the storage and absorption of electrolytes, and improving the cycling performance of the battery.
Smart Images
Figure CN222953307U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of lithium ion batteries, in particular to a lithium ion battery diaphragm. Background Art
[0002] As one of the important components inside the battery, the battery separator plays the role of isolating the positive and negative electrodes to prevent short circuits, providing a transmission channel for lithium ions, and automatically shutting down at high temperatures to prevent battery fires. Polymer materials such as PP (polypropylene) and PE (polyethylene) are widely used on the market. They have excellent mechanical properties and can prevent lithium dendrites from piercing the separator and causing short circuits. However, their heat resistance is poor. When the temperature is high, the separator will shrink, causing a short circuit between the positive and negative electrodes. Therefore, inorganic coated separators came into being. They can improve the high temperature resistance of the separator and ensure that the battery can still work normally under high temperature conditions.
[0003] However, in actual use, it was found that the bonding force between the inorganic matter and the diaphragm itself in the existing battery diaphragm is relatively low. During use, the diaphragm surface is prone to unevenness and the inorganic matter and the diaphragm are separated, which will affect the overall use of the battery diaphragm. In addition, in order to ensure the passage rate of the electrolyte, the porosity of the diaphragm will be increased, but the above method will reduce the overall strength, thereby increasing the chance of the diaphragm being punctured. Utility Model Content
[0004] The purpose of the utility model is to provide a lithium ion battery separator in order to solve the above-mentioned problems.
[0005] The technical solution adopted by the utility model is as follows: a lithium-ion battery separator comprises a substrate layer, a protective portion is provided on the surface of the substrate layer, and the protective portion comprises an adhesion coating, a high temperature resistant coating and a corrosion resistant layer from the inside to the outside;
[0006] The upper end surface of the protection portion is sunken to form a plurality of concave surfaces extending into the adhesion coating layer, and the concave surfaces are evenly arranged on the protection portion.
[0007] In a preferred embodiment, the substrate layer is made entirely of PP or PE material, and the thickness of the substrate layer is 4-20 μm.
[0008] In a preferred embodiment, the adhesion coating is entirely made of polyurethane resin adhesive, and the thickness of the adhesion coating is 0.5-2 μm.
[0009] In a preferred embodiment, the outer surface of the substrate layer has a rough surface.
[0010] In a preferred embodiment, the high temperature resistant coating is formed by coating with one of aluminum oxide, silicon oxide, boehmite, and boron nitride materials, and the thickness of the high temperature resistant coating is 0.5-3 μm.
[0011] In a preferred embodiment, the corrosion-resistant layer is entirely formed by coating with BaSO4 material, and the thickness of the corrosion-resistant layer is 1.5-3 μm.
[0012] In summary, due to the adoption of the above technical solution, the beneficial effects of the utility model are:
[0013] 1. In the present invention, an adhesion coating and a rough surface are added to the substrate layer. When the high temperature resistant coating is subsequently applied, the bonding strength and toughness between the high temperature resistant coating and the substrate layer can be increased, so that the subsequent diaphragm delamination phenomenon is not likely to occur;
[0014] 2. In the utility model, a corrosion-resistant layer is added on the substrate layer. The BaSO4 material has the characteristics of heat resistance, good strength and acid and alkali resistance. It can ensure the overall porosity while ensuring the overall strength, so that it is not easy to be punctured and deformed;
[0015] 3. In the utility model, a plurality of concave surfaces are designed on the protection part, which can be used for auxiliary storage operation of electrolyte during the battery liquid absorption process, and is beneficial to the absorption of electrolyte during the circulation process. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 It is a schematic diagram of the layered structure of the utility model as a whole;
[0017] Figure 2 It is a structural cross-sectional view of the protection part in the utility model.
[0018] Markings in the figure: 1-protection part, 10-concave surface, 101-corrosion-resistant layer, 102-high temperature resistant coating, 103-adhesion coating, 2-substrate layer, 3-rough surface. DETAILED DESCRIPTION
[0019] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.
[0020] Reference Figure 1-2 The lithium-ion battery separator comprises a substrate layer 2, a protective portion 1 is provided on the surface of the substrate layer 2, and the protective portion 1 comprises an adhesion coating 103, a high temperature resistant coating 102 and a corrosion resistant layer 101 from the inside to the outside, the substrate layer 2 is made of PP or PE as a whole, and the thickness of the substrate layer 2 is 4-20 μm.
[0021] Reference Figure 2As shown, the upper end surface of the protective portion 1 is sunken to form a plurality of concave surfaces 10 extending into the adhesion coating 103, and the concave surfaces 10 are evenly arranged on the protective portion 1. A plurality of groups of concave surfaces 10 are designed on the protective portion, which can be used for auxiliary storage operations of the electrolyte during the battery liquid absorption process, and are beneficial to the absorption of the electrolyte during the circulation process.
[0022] The concave surface 10 may be circular, hexagonal or other shapes.
[0023] Furthermore, the adhesion coating 103 is a polyurethane resin adhesive as a whole, the thickness of the adhesion coating 103 is 0.5~2μm, the outer surface of the substrate layer 2 has a rough surface 3, and the adhesion coating 103 and the rough surface 3 are added to the substrate layer 2. When the high-temperature resistant coating 102 is subsequently coated, the bonding strength and toughness between the high-temperature resistant coating 102 and the substrate layer 2 can be increased, so that the subsequent diaphragm delamination phenomenon is not easy to occur.
[0024] Among them, the polyurethane resin adhesive also has excellent toughness, thus ensuring the overall structural stability.
[0025] Furthermore, the high temperature resistant coating 102 is formed by coating one or more materials selected from the group consisting of aluminum oxide, silicon oxide, boehmite, and boron nitride. The thickness of the high temperature resistant coating 102 is 0.5-3 μm.
[0026] Furthermore, the corrosion-resistant layer 101 is formed by coating with BaSO4 material as a whole. The thickness of the corrosion-resistant layer 101 is 1.5-3 μm. BaSO4 material has the characteristics of heat resistance, good strength and acid and alkali resistance. It can ensure the overall porosity while ensuring the overall strength, so it is not easy to be punctured and deformed.
[0027] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A lithium-ion battery separator, comprising a substrate layer, characterized in that: The surface of the substrate layer is provided with a protective portion, and the protective portion comprises an adhesion coating, a high temperature resistant coating and a corrosion resistant layer from the inside to the outside; The upper end surface of the protection portion is sunken to form a plurality of concave surfaces extending into the adhesion coating layer, and the concave surfaces are evenly arranged on the protection portion.
2. The lithium ion battery separator according to claim 1, characterized in that: The substrate layer is made of PP or PE material as a whole, and the thickness of the substrate layer is 4-20 μm.
3. The lithium ion battery separator according to claim 1, characterized in that: The adhesion coating is entirely made of polyurethane resin adhesive, and the thickness of the adhesion coating is 0.5-2 μm.
4. The lithium ion battery separator according to claim 1, characterized in that: The outer surface of the substrate layer has a rough surface.
5. The lithium ion battery separator according to claim 1, characterized in that: The high temperature resistant coating is formed by coating one of aluminum oxide, silicon oxide, boehmite and boron nitride materials, and the thickness of the high temperature resistant coating is 0.5-3 μm.
6. The lithium ion battery separator according to claim 1, characterized in that: The corrosion-resistant layer is formed by coating BaSO4 material as a whole, and the thickness of the corrosion-resistant layer is 1.5-3 μm.