Diaphragm, electrode assembly, battery and electric equipment
By employing a base film, a solid electrolyte layer, and a lattice-distributed cold-pressed binder structure in the separator, the problem of increased DC internal resistance of the battery caused by cold pressing is solved, achieving efficient charging and discharging of the battery and reduced cost.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- BEIJING CHEHEJIA AUTOMOBILE TECH CO LTD
- Filing Date
- 2025-03-27
- Publication Date
- 2026-05-08
AI Technical Summary
The use of cold-pressed adhesive in existing composite separators significantly increases the DC internal resistance of the battery, affecting its fast charge and discharge performance, and also results in higher production costs.
The membrane structure includes a base film and a solid electrolyte layer. The adhesive layer uses a lattice-distributed cold-pressed adhesive instead of a hot-pressed adhesive, and is combined with a ceramic layer to improve mechanical strength and thermal stability, ensuring lithium-ion conduction efficiency.
This reduces the battery's DC internal resistance, improves its charge/discharge performance and safety, and reduces production costs.
Smart Images
Figure CN224217665U_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of battery technology, specifically relating to a separator, electrode assembly, battery, and electrical device. Background Technology
[0002] Composite separators are a commonly used battery separator structure. Existing composite separators generally have an adhesive layer, which uses a hot-press adhesive that is viscous at 100 degrees Celsius, and is bonded to the positive and negative electrode sheets through a hot-pressing process.
[0003] Replacing the hot-press adhesive in the composite separator with a cold-press adhesive that is viscous at room temperature allows the hot-pressing process to be changed to a cold-pressing process. This helps reduce battery production costs and improves battery safety to some extent. However, the cold-press adhesive is a non-active area in the battery, which can easily lead to a significant increase in the battery's DCR (Direct Current Resistance), thereby affecting the battery's fast charge and discharge performance. Utility Model Content
[0004] In view of the above problems, the present invention provides a diaphragm, electrode assembly, battery and electrical device that overcomes or at least partially solves the above problems.
[0005] To solve the above-mentioned technical problems, this application is implemented as follows:
[0006] In a first aspect, embodiments of this application provide a diaphragm, comprising:
[0007] A structural layer, the structural layer comprising a base film and a solid electrolyte layer, the solid electrolyte layer being disposed on at least one side of the base film;
[0008] The adhesive layer comprises two layers, which are respectively disposed on both sides of the structural layer. The adhesive layer includes a plurality of cold-pressed adhesive balls distributed in a dot matrix pattern.
[0009] Optionally, the coating radius of the cold-pressed gel is a, where 0 cm < a ≤ 0.5 cm.
[0010] Optionally, the interval between two adjacent cold-pressed colloids is b, where 0cm < b ≤ 1cm.
[0011] Optionally, the thickness of the adhesive layer is c, where 0.5 μm ≤ c ≤ 10 μm.
[0012] Optionally, the thickness of the solid electrolyte layer is d, where 0.5μm≤d≤10μm.
[0013] Optionally, the particle size of the solid electrolyte particles in the solid electrolyte layer is e, where 0.1 μm ≤ e ≤ 3 μm.
[0014] Optionally, the structural layer further includes a ceramic layer disposed on the side of the base film opposite to the solid electrolyte layer.
[0015] Optionally, the thickness of the ceramic layer is f, where 0.5μm≤f≤10μm.
[0016] Optionally, the particle size of the ceramic particles in the ceramic layer is g, where 0.1μm≤g≤3μm.
[0017] Secondly, embodiments of this application provide an electrode assembly, which includes a positive electrode, a negative electrode, and a separator as described in the first aspect; the positive electrode and the negative electrode are respectively disposed on both sides of the separator.
[0018] Thirdly, embodiments of this application provide a battery that includes the electrode assembly as described in the second aspect.
[0019] Fourthly, embodiments of this application provide an electrical device that includes a battery as described in the third aspect.
[0020] In this embodiment, the separator includes a structural layer and an adhesive layer. The structural layer includes a base film and a solid electrolyte layer, with the solid electrolyte layer disposed on at least one side of the base film. The adhesive layer is disposed on both sides of the structural layer, and each side of the adhesive layer includes a plurality of cold-pressed adhesive particles distributed in a dot matrix. The cold-pressed adhesive particles can replace the hot-pressed adhesive used in the prior art for bonding with the positive and negative electrode sheets, thus avoiding the introduction of a hot-pressing process during production, which helps reduce battery production and processing costs and ensures battery safety performance. The multiple cold-pressed adhesive particles distributed in a dot matrix can reduce the distribution area of the cold-pressed adhesive particles on the surface of the structural layer while ensuring bonding effect, increasing the air permeability of the separator and thus reducing the separator impedance. The solid electrolyte layer can improve the transmission efficiency of lithium ions when passing through the separator, thereby reducing the DC internal resistance of the battery. The solid electrolyte layer and the dot matrix-distributed cold-pressed adhesive particles can eliminate the influence of the cold-pressed adhesive on the separator impedance, thereby helping to reduce the DC internal resistance of the battery using the above-mentioned separator and reducing the production and processing costs of the battery using the above-mentioned separator.
[0021] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description
[0022] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:
[0023] Figure 1This is a schematic diagram of the diaphragm structure according to one embodiment of this application;
[0024] Figure 2 This is a schematic diagram of the diaphragm structure according to one embodiment of this application;
[0025] Figure 3 This is a schematic diagram of the diaphragm structure according to one embodiment of this application;
[0026] Figure 4 This is a schematic diagram of the structure of cold-pressed colloids distributed in a lattice pattern in one embodiment of this application;
[0027] Figure 5 This is a schematic diagram of the structure of the electrode assembly described in one embodiment of this application;
[0028] Figure 6 This is a schematic diagram of the structure of the electrode assembly described in one embodiment of this application;
[0029] Figure 7 This is a schematic diagram of the structure of the electrode assembly described in one embodiment of this application;
[0030] Reference numerals: 1. Separator; 11. Structural layer; 111. Base membrane; 112. Solid electrolyte layer; 113. Ceramic layer; 12. Adhesive layer; 121. Cold-pressed gel; 2. Positive electrode; 3. Negative electrode. Detailed Implementation
[0031] The embodiments of this utility model will now be described in detail. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.
[0032] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.
[0033] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.
[0034] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0035] The separator is one of the key components in a battery, primarily used to isolate the positive and negative electrodes, prevent short circuits, and allow lithium ions to pass through to complete electrochemical reactions. During use, the positive and negative electrodes are attached to both sides of the separator to prevent direct contact between them, thus avoiding internal short circuits and ensuring battery safety and stability. The separator has a uniformly distributed microporous structure, which allows lithium ions in the electrolyte to pass through during battery charging and discharging, forming a current loop and ensuring the battery's charging and discharging performance.
[0036] With advancements in battery technology, engineers are placing increasingly higher demands on the performance of separators. Existing separators need to achieve separation of the positive and negative electrodes, facilitate lithium-ion conduction, and simultaneously possess good thermal stability and mechanical strength. To address this, one type of separator employs a composite design, specifically comprising a base membrane and ceramic layers coated on both sides of the base membrane. The ceramic layers significantly improve the separator's high-temperature resistance and mechanical strength. During assembly, an adhesive layer is first coated onto the ceramic layer surface, and then the positive and negative electrode sheets are respectively attached to both sides of the separator. The adhesive layer uses a thermosetting adhesive with tackiness at 100 degrees Celsius and is bonded to the positive and negative electrode sheets through a thermosetting process.
[0037] Replacing hot-press adhesive with cold-press adhesive, which is tacky at room temperature, allows the hot-pressing process to be changed to a cold-pressing process. This helps reduce battery production costs and improves battery safety to some extent. However, cold-press adhesive is located in a non-active area within the battery and is applied under higher pressure, which can easily increase the impedance of the separator, leading to a significant increase in the battery's discharge rate (DCR) and affecting its fast charge / discharge performance.
[0038] To this end, the first aspect of this application provides a diaphragm to overcome the impedance increase problem caused by applying cold-pressed adhesive in the diaphragm.
[0039] Example 1:
[0040] refer to Figure 1 The separator 1 described in Embodiment 1 of this application specifically includes a structural layer 11 and an adhesive layer 12. The structural layer 11 includes a base membrane 111 and a solid electrolyte layer 112. The base membrane 111 is the core component of the battery separator 1, and it is typically made of polyolefin materials, such as polyethylene and polypropylene. In some cases, the base membrane 111 can also be made of non-woven fabric, that is, the base membrane 111 is made of polyester, aramid, or other fiber materials through a non-woven process. The base membrane 111 determines the basic performance of the separator 1, such as basic mechanical strength, lithium-ion conductivity, and thermal stability. The base membrane 111 has a microporous structure, which allows lithium ions to pass through while isolating the positive electrode 2 and the negative electrode 3.
[0041] A solid electrolyte layer 112 is disposed on at least one side of the base film 111. In other words, the solid electrolyte layer 112 can be as follows: Figure 3 As shown, it is coated on one side of the base film 111, or as... Figure 1 The solid electrolyte layer 112 is coated on both sides of the base film 111. Specifically, it can be composed of any one of the following materials: lithium aluminum titanium phosphate, lithium aluminum germanium phosphate, lithium lanthanum zirconium oxide, lithium lanthanum titanium oxide, or sulfides, or a mixture of two, three, or more of the above materials. These materials are present in the solid electrolyte layer 112 in the form of particles, and the gaps between the particles constitute a microporous structure for the passage of lithium ions.
[0042] refer to Figure 5 The adhesive layer 12 is disposed on both sides of the structural layer 11, and each side of the adhesive layer 12 includes a plurality of cold-pressed adhesive balls 121 distributed in a dot matrix. Specifically, the thickness of the cold-pressed adhesive balls 121 is the thickness of the adhesive layer 12. The cross-sectional shape of the cold-pressed adhesive balls 121 in the thickness direction can be determined according to actual needs; for example, it can be a regular geometric shape such as a circle, rectangle, or triangle, or it can be some irregular aggregate shape. (Reference) Figure 4In this embodiment, the cross-sectional shape of the cold-pressed adhesive agglomerate 121 in the thickness direction is preferably circular to meet the needs of actual production and processing. The cold-pressed adhesive agglomerates 121 in the same adhesive layer 12 are distributed in a lattice, that is, there are multiple cold-pressed adhesive agglomerates 121, which are dispersed in the surface area of the structural layer 11, and there is a certain interval between any two adjacent cold-pressed adhesive agglomerates 121. The cold-pressed adhesive is specifically a material with a certain viscosity at room temperature, which can ensure that the positive electrode 2 and the negative electrode 3 are fully bonded to the separator 1. For example, one of the following can be used: functionalized polymethyl methacrylate, functionalized polyvinylidene fluoride, functionalized polyvinylidene fluoride-hexafluoropropylene, and other polyvinylidene fluoride polymers; or a mixture of two, three, or even more of these materials can be used.
[0043] By using cold-pressed adhesive clusters 121 instead of the hot-pressed adhesive in existing technologies to bond the separator 1 to the positive electrode 2 and the negative electrode 3, the hot-pressing process can be avoided during production, which helps reduce battery production and processing costs and ensures battery safety performance. Multiple cold-pressed adhesive clusters 121 are arranged in a dot matrix pattern, which reduces the distribution area of the cold-pressed adhesive clusters 121 on the surface of the structural layer 11 while ensuring bonding effectiveness. This reduces the coverage of the adhesive layer 12 on the structural layer 11, allowing most of the micropores in the structural layer 11 to be open outside the adhesive layer 12, thereby increasing the permeability of the separator 1, reducing the impedance of the separator 1, and ensuring efficient lithium-ion conduction within the separator 1.
[0044] The solid electrolyte in the solid electrolyte layer 112 is a material specifically designed for conducting lithium ions and has high lithium-ion conductivity. Therefore, the solid electrolyte layer 112 can directly participate in lithium-ion conduction, significantly reducing the impedance of the separator 1. The solid electrolyte layer 112, composed of a solid electrolyte, has a uniform lithium-ion conduction path, providing a more efficient lithium-ion transport channel, thereby reducing the overall impedance of the separator 1. Therefore, the solid electrolyte layer 112 can improve the transport efficiency of lithium ions through the separator 1, thereby reducing the DC internal resistance of the battery.
[0045] The solid electrolyte layer 112 and the cold-pressed adhesive particles 121 distributed in a lattice eliminate the impedance effect of the cold-pressed adhesive on the separator 1, thus helping to reduce the DC internal resistance of the battery using the separator 1, and at the same time reducing the production and processing cost of the battery using the separator 1.
[0046] refer to Figure 4 , Figure 5Optionally, the cold-pressed adhesive atom 121 has a circular cross-sectional shape in its thickness direction, and its coating radius is 'a'. 'a' is greater than 0 cm and less than or equal to 0.5 cm. For example, the coating radius of the cold-pressed adhesive atom 121 can be 0.05 cm, 0.1 cm, 0.15 cm, 0.2 cm, 0.25 cm, 0.3 cm, 0.35 cm, 0.4 cm, 0.45 cm, 0.5 cm, etc. Having a coating radius of no more than 0.5 cm allows for effective adhesion while reducing the coverage area of a single cold-pressed adhesive atom 121 on the structural layer 11. This helps reduce the coverage of the adhesive layer 12 on the structural layer 11, allowing most of the micropores in the structural layer 11 to be open outside the adhesive layer 12, thereby increasing the permeability of the separator 1, reducing the impedance of the separator 1, and ensuring efficient lithium-ion conduction in the separator 1.
[0047] refer to Figure 4 , Figure 5 Optionally, the interval between two adjacent cold-pressed adhesive balls 121 is b, where b is greater than 0 cm and less than or equal to 1 cm. For example, the interval between two adjacent cold-pressed adhesive balls 121 can be 0.05 cm, 0.1 cm, 0.15 cm, 0.2 cm, 0.25 cm, 0.3 cm, 0.35 cm, 0.4 cm, 0.45 cm, 0.5 cm, 0.55 cm, 0.6 cm, 0.65 cm, 0.7 cm, 0.75 cm, 0.8 cm, 0.85 cm, 0.9 cm, 0.95 cm, 1 cm, etc. In this embodiment, the cold-pressed adhesive balls 121 in the same adhesive layer 12 are arranged in an array along two orthogonal directions, and the interval between any two adjacent cold-pressed adhesive balls 121 is no greater than 1 cm. This effectively ensures the bonding ability of the adhesive layer 12 while minimizing the coverage area of the adhesive layer 12 on the structural layer 11. This ensures the adhesion between the separator 1 and the positive electrode 2 and the negative electrode 3, while maximizing the air permeability of the separator 1 to further reduce its resistance.
[0048] refer to Figure 4 , Figure 5Optionally, in this embodiment, the thickness of the adhesive layer 12 is c, where c is greater than or equal to 0.5 μm and less than or equal to 10 μm. For example, the specific thickness of the adhesive layer 12 can be 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, 8.5 μm, 9 μm, 9.5 μm, 10 μm, etc. Within this range, the thickness of the adhesive layer 12 is close to or equal to 0.5 μm, which can further reduce the influence of the adhesive layer 12 on the impedance of the diaphragm 1 while ensuring the bonding ability. The adhesive layer 12 has a thickness of approximately 10 μm, which can increase the adhesive thickness between the separator 1 and the positive electrode 2 and the negative electrode 3, and further improve the reliability of the adhesive effect between the separator 1 and the positive electrode 2 and the negative electrode 3.
[0049] refer to Figure 5 , Figure 7 Optionally, the thickness of the solid electrolyte layer 112 is d, where d is greater than or equal to 0.5 μm and less than or equal to 10 μm. For example, the specific thickness of the solid electrolyte layer 112 can be 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, 8.5 μm, 9 μm, 9.5 μm, 10 μm, etc. Within this range, a solid electrolyte layer 112 thickness close to or equal to 0.5 μm can reduce the space occupied by the separator 1, thereby reducing the space occupied by the electrode assembly after the separator 1, positive electrode 2, and negative electrode 3 are assembled, and thus improving the energy density of the battery. A solid electrolyte layer 112 thickness close to or equal to 1 μm can further improve the heat resistance, mechanical properties, etc. of the separator 1, thereby further improving the safety of the battery.
[0050] refer to Figure 5 , Figure 7 Optionally, in the solid electrolyte layer 112, the particle size of the solid electrolyte particles is e. e is greater than or equal to 0.1 μm and less than or equal to 3 μm. For example, the particle size of the solid electrolyte particles in the solid electrolyte layer 112 can specifically be 0.1 μm, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, etc. Within this range, the particle size of the solid electrolyte particles is close to or equal to 0.1 μm, which is beneficial to reducing the thickness of the solid electrolyte layer 112, thereby reducing the space occupied by the separator 1. The particle size of the solid electrolyte particles is close to or equal to 3 μm, which is beneficial to increasing the thickness of the solid electrolyte layer 112, and thus is beneficial to further improving the heat resistance, mechanical properties, etc. of the separator 1, so as to further improve the safety of the battery.
[0051] refer to Figure 6Optionally, the structural layer 11 further includes a ceramic layer 113, which is disposed on the side of the base membrane 111 facing away from the solid electrolyte. In other words, in this embodiment, one side of the base membrane 111 can be a solid electrolyte layer 112, and the other side can be a ceramic layer 113. Specifically, the ceramic layer 113 can be composed of any one of the following materials: boehmite, alumina, silicon dioxide, titanium dioxide, zirconium oxide, barium sulfate, and magnesium hydroxide, or a mixture of two, three, or even more of the above materials. In some cases, the ceramic layer 113 can also incorporate materials such as aramid. These materials are present in the ceramic layer 113 in the form of particles, and the gaps between the particles constitute a microporous structure for lithium ions to pass through. The ceramic layer 113 helps to improve the mechanical strength and heat resistance of the separator 1, and further enhances the safety of the battery.
[0052] refer to Figure 6 Optionally, the thickness of the ceramic layer 113 is f, where f is greater than or equal to 0.5 μm and less than or equal to 10 μm. For example, the specific thickness of the ceramic layer 113 can be 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, 8.5 μm, 9 μm, 9.5 μm, 10 μm, etc. Within this range, a ceramic layer 113 thickness close to or equal to 0.5 μm can reduce the space occupied by the separator 1, thereby reducing the space occupied by the electrode assembly after the separator 1, positive electrode 2, and negative electrode 3 are assembled, and thus improving the energy density of the battery. A ceramic layer 113 thickness close to or equal to 10 μm can further improve the heat resistance, mechanical properties, etc. of the separator 1, thereby further improving the safety of the battery.
[0053] Optionally, the particle size of the ceramic particles in the ceramic layer 113 is g, where g is greater than or equal to 0.1 μm and less than or equal to 3 μm. For example, the particle size of the ceramic particles in the ceramic layer 113 can specifically be 0.1 μm, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, etc. Within this range, a particle size close to or equal to 0.1 μm is beneficial for reducing the thickness of the ceramic layer 113, thereby reducing the space occupied by the separator 1. A particle size close to or equal to 3 μm is beneficial for increasing the thickness of the ceramic layer 113, thus further improving the heat resistance, mechanical properties, etc., of the separator 1, thereby further improving the safety of the battery.
[0054] For ease of understanding, this embodiment is described in conjunction with a specific diaphragm 1 manufacturing process. (See reference...) Figure 1In this embodiment, one side of the base film 111 is a ceramic layer 113, and the other side is a solid electrolyte layer 112. An adhesive layer 12 is coated on the outer side of the structural layer 11, and the adhesive layer 12 includes a plurality of cold-pressed polymeric particles 121 distributed in a lattice. Specifically, the cold-pressed polymeric particles 121 are a mixture of functionalized polymethyl methacrylate and functionalized polyvinylidene fluoride, wherein the proportion of functionalized polymethyl methacrylate is 10% to 90%.
[0055] The ceramic layer 113 specifically uses boehmite. In preparing the ceramic layer 113 coating, thickeners, binders, and wetting agents are first added to deionized water and stirred until completely dissolved. Boehmite particles with a particle size of 0.3μm to 0.5μm are added to the mixture of deionized water and additives, stirred thoroughly, and then ground for a certain period. The first grinding time can be no less than 1 hour and no more than 4 hours. A surfactant is added to the initially ground mixture, and then it is ground again for a certain period. The second grinding time can be no less than 6 hours and no more than 12 hours.
[0056] After the second grinding, the resulting mixture is the aqueous ceramic slurry. This aqueous ceramic slurry comprises 20 wt% to 40 wt% deionized water and 30 wt% to 50 wt% boehmite particles. The aqueous ceramic slurry is coated onto one side of the base membrane 111, and then the base membrane 111 coated with the aqueous ceramic slurry is placed in an oven to dry for 25 to 120 minutes. The oven temperature is preferably controlled between 40 and 70 degrees Celsius. After drying, a semi-finished diaphragm 1 is obtained. In this semi-finished diaphragm 1, one side of the base membrane 111 is covered with a ceramic layer 113 with a thickness of 2 μm to 3 μm.
[0057] Next, the coating for the solid electrolyte layer 112 is prepared. Specifically, the solid electrolyte layer 112 uses lithium titanium aluminum phosphate. During preparation, thickeners, binders, and wetting agents are first added to deionized water and stirred until completely dissolved. Lithium titanium aluminum phosphate is then added to the mixture of deionized water and additives, and after thorough mixing, it is ground for a certain period. The first grinding time can be no less than 1 hour and no more than 8 hours. Then, a surfactant is added to the ground mixture, and it is ground again for a certain period. The second grinding time can be no less than 1 hour and no more than 12 hours.
[0058] After the second grinding, the resulting mixture is the aqueous slurry of the solid electrolyte layer 112. This aqueous slurry includes 10 wt% to 20 wt% deionized water and 30 wt% to 50 wt% lithium aluminum titanium phosphate particles. The aqueous slurry is coated onto the side of the base membrane 111 facing away from the ceramic layer 113, and then the base membrane 111 coated with the aqueous slurry is placed in an oven to dry for 25 minutes to 600 minutes. The oven temperature is preferably controlled between 60 degrees Celsius and 80 degrees Celsius. After drying, a semi-finished diaphragm 1 is obtained. In this semi-finished diaphragm 1, one side of the base membrane 111 is covered with a ceramic layer 113 with a thickness of 2 μm to 3 μm, and the other side is covered with a solid electrolyte layer 112 with a thickness of 2 μm to 3 μm.
[0059] Finally, the coating for adhesive layer 12 is prepared. First, functionalized polymethyl methacrylate powder, functionalized polyvinylidene fluoride powder, and water are added to a double planetary mixer and thoroughly stirred for 30 to 60 minutes. During this time, the mixture of functionalized polymethyl methacrylate powder and functionalized polyvinylidene fluoride powder is fully dissolved in water. This mixed solution is the coating for adhesive layer 12, wherein the weight percentage of functionalized polymethyl methacrylate is 5 wt% to 50 wt%, and the mass fraction of functionalized polyvinylidene fluoride is 5 wt% to 50 wt%. This mixed solution is coated onto both sides of the semi-finished diaphragm 1 in a dot matrix pattern, and then the semi-finished diaphragm 1 with this mixed solution is placed in an oven to dry for 15 to 30 minutes. The oven temperature is controlled at 30 to 60 degrees Celsius. After oven baking, the finished diaphragm 1 is obtained. At this point, the finished diaphragm 1 has an adhesive layer 12 with a thickness of 5 μm to 10 μm.
[0060] Example 2
[0061] For ease of understanding, Embodiment 2 of this application is described in conjunction with a specific diaphragm 1 manufacturing process. In Embodiment 2 of this application, reference is made to... Figure 3 The structural layer 11 comprises only a base film 111 and a solid electrolyte layer 112 coated on one side of the base film 111. An adhesive layer 12 is coated on the outer side of the structural layer 11, comprising a plurality of cold-pressed polymeric particles 121 arranged in a lattice. Specifically, the cold-pressed polymeric particles 121 are a mixture of functionalized polymethyl methacrylate and functionalized polyvinylidene fluoride-hexafluoropropylene, wherein the proportion of functionalized polymethyl methacrylate is 40% to 80%.
[0062] First, the coating for the solid electrolyte layer 112 is prepared. Specifically, the solid electrolyte layer 112 uses lithium titanium aluminum phosphate. During preparation, thickeners, binders, and wetting agents are added to deionized water and stirred until completely dissolved. Lithium titanium aluminum phosphate particles with a particle size of 0.2 μm to 0.9 μm are added to the mixture of deionized water and additives, and after thorough mixing, the mixture is ground for a certain period. The first grinding time can be no less than 2 hours and no more than 12 hours. Then, a surfactant is added to the ground mixture, and it is ground again for a certain period. The second grinding time can be no less than 3 hours and no more than 5 hours.
[0063] After the second grinding, the resulting mixture is the aqueous slurry of the solid electrolyte layer 112. This aqueous slurry includes 10 wt% to 40 wt% deionized water and 20 wt% to 40 wt% lithium aluminum titanium phosphate particles. The aqueous slurry is coated onto one side of the base membrane 111, and then the base membrane 111 coated with the aqueous slurry is placed in an oven to dry for 5 to 720 minutes. The oven temperature is preferably controlled between 50 and 70 degrees Celsius. After drying, a semi-finished diaphragm 1 is obtained. In this semi-finished diaphragm 1, one side of the base membrane 111 is covered with a solid electrolyte layer 112 with a thickness of 1 μm to 3 μm.
[0064] Finally, the coating for adhesive layer 12 is prepared. First, functionalized polymethyl methacrylate powder, functionalized polyvinylidene fluoride-hexafluoropropylene powder, and water are added to a double planetary mixer and stirred thoroughly for 30 to 90 minutes. At this point, the mixture of functionalized polymethyl methacrylate powder and functionalized polyvinylidene fluoride-hexafluoropropylene powder is fully dissolved in water. This mixed solution is the coating for adhesive layer 12, wherein the total mass fraction of functionalized polymethyl methacrylate and functionalized polyvinylidene fluoride is 10 wt% to 30 wt%. This mixed solution is coated onto both sides of the semi-finished diaphragm 1 in a dot matrix pattern, and then the semi-finished diaphragm 1 with this mixed solution is placed in an oven to dry for 5 to 30 minutes. The oven temperature is controlled at 40 to 60 degrees Celsius. After baking in the oven, the finished diaphragm 1 is obtained. At this point, the finished diaphragm 1 has an adhesive layer 12 with a thickness of 4 μm to 6 μm.
[0065] To demonstrate the difference from existing diaphragms, this application provides Comparative Example 1 and Comparative Example 2 to illustrate the differences and technical advantages of the diaphragm 1 described in the embodiments of this application compared to existing diaphragms.
[0066] Comparative Example 1
[0067] In Comparative Example 1, the diaphragm adopts an existing structure. Specifically, both sides of the base membrane in the diaphragm are coated with ceramic layers, and an adhesive layer is coated on the outside of the ceramic layers. The adhesive layer is uniformly sprayed and covers the surface of the ceramic layers.
[0068] The ceramic layer specifically uses boehmite. In preparing the ceramic coating, thickeners, binders, and wetting agents are first added to deionized water and stirred until completely dissolved. Boehmite particles with a particle size of 0.3μm to 0.5μm are then added to the mixture of deionized water and additives, stirred thoroughly, and then ground for a certain period. The first grinding time can be no less than 2 hours and no more than 6 hours. A surfactant is then added to the initially ground mixture, and then it is ground again for a certain period. The second grinding time can be no less than 3 hours and no more than 5 hours.
[0069] After the second grinding, the resulting mixture is the aqueous ceramic slurry. This slurry contains 30 wt% to 50 wt% deionized water and 30 wt% to 40 wt% boehmite particles. The aqueous ceramic slurry is coated onto both sides of a base membrane, and then the base membrane coated with the slurry is placed in an oven to dry for 5 to 90 minutes. The oven temperature is preferably controlled between 50 and 60 degrees Celsius. After drying, a semi-finished diaphragm is obtained. In this semi-finished diaphragm, both sides of the base membrane are covered with a ceramic layer with a thickness of 2 μm to 3 μm.
[0070] Finally, the coating for the adhesive layer is prepared. First, functionalized polymethyl methacrylate powder, functionalized polyvinylidene fluoride powder, and water are added to a double planetary mixer and stirred thoroughly for 20 to 90 minutes. During this time, the mixture of functionalized polymethyl methacrylate powder and functionalized polyvinylidene fluoride powder is fully dissolved in water. This mixed solution is the coating for the adhesive layer, wherein the total mass fraction of functionalized polymethyl methacrylate and functionalized polyvinylidene fluoride is 5 wt% to 30 wt%. This mixed solution is uniformly coated on both sides of the semi-finished diaphragm, and then the semi-finished diaphragm with this mixed solution is placed in an oven to dry for 5 to 80 minutes. The oven temperature is controlled at 40°C to 60°C. After oven baking, the finished diaphragm is obtained. At this point, the finished diaphragm has an adhesive layer with a thickness of 5 μm to 10 μm.
[0071] Comparative Example 2
[0072] In Comparative Example 2, the diaphragm uses an existing structure. Specifically, a ceramic layer is coated on one side of the base membrane in the diaphragm, and an adhesive layer is coated on the outer side of both the base membrane and the ceramic layer. The adhesive layer is uniformly sprayed and covers the surfaces of the base membrane and the ceramic layer.
[0073] The ceramic layer is specifically made of alumina. In preparing the ceramic coating, thickeners, binders, and wetting agents are first added to deionized water and stirred until completely dissolved. Alumina particles with a particle size of 0.6 μm to 0.8 μm are then added to the mixture of deionized water and additives, stirred thoroughly, and ground for a certain period. The first grinding time can be no less than 3 hours and no more than 8 hours. A surfactant is then added to the initially ground mixture, and it is ground again for a certain period. The second grinding time can be no less than 2 hours and no more than 6 hours.
[0074] After the second grinding, the resulting mixture is the aqueous ceramic slurry. This slurry comprises 20 wt% to 60 wt% deionized water and 10 wt% to 30 wt% alumina particles. The aqueous ceramic slurry is coated onto one side of a base membrane, and then the base membrane coated with the slurry is placed in an oven to dry for 5 to 90 minutes. The oven temperature is preferably controlled between 50 and 60 degrees Celsius. After drying, a semi-finished diaphragm is obtained. In this semi-finished diaphragm, one side of the base membrane is covered with a ceramic layer with a thickness of 1 μm to 3 μm.
[0075] Finally, the coating for the adhesive layer is prepared. First, functionalized polymethyl methacrylate powder, functionalized polyvinylidene fluoride powder, and water are added to a double planetary mixer and stirred thoroughly for 10 to 90 minutes. At this point, the mixture of functionalized polymethyl methacrylate powder and functionalized polyvinylidene fluoride powder is fully dissolved in water. This mixed solution is the coating for the adhesive layer, wherein the total mass fraction of functionalized polymethyl methacrylate and functionalized polyvinylidene fluoride is 10 wt% to 40 wt%. This mixed solution is uniformly coated on both sides of the semi-finished diaphragm, and then the semi-finished diaphragm with this mixed solution is placed in an oven and dried for 5 to 80 minutes. The oven temperature is controlled at 40°C to 60°C. After oven baking, the finished diaphragm is obtained. The finished diaphragm has an adhesive layer with a thickness of 4 μm to 6 μm.
[0076] The membranes obtained in Example 1, Example 2, Comparative Example 1, and Comparative Example 2 were subjected to performance tests, and the results are shown in Table 1 below. Table 1 shows the test results of the membranes obtained in Example 1, Example 2, Comparative Example 1, and Comparative Example 2 in heat shrinkage test, DCR test, SOH (State of Health) test, and capacity retention rate test.
[0077] Table 1. Diaphragm performance test data
[0078]
[0079] As shown in Table 1, the separators obtained in Examples 1, 2, 1, and 2 were all tested in a ternary high-nickel battery. After being placed at 150 degrees Celsius for 1 hour, the thermal shrinkage rates of the separators obtained in Examples 1, 2, 1, and 2 were 0.8%, 2.2%, 0.5%, and 2.1%, respectively. This indicates that the ceramic layer in the embodiments of this application can improve the separator's ability to withstand high temperatures.
[0080] When the separators obtained in Examples 1, 2, 1, and 2 (Comparative Examples) are applied in ternary high-nickel batteries, the DC internal resistances of the batteries are 0.6 mΩ, 0.5 mΩ, 1.3 mΩ, and 1 mΩ, respectively. The DC internal resistance of the batteries using the separators described in Examples 1 and 2 of this application is half that of the batteries using the separators described in Comparative Examples 1 and 2. Therefore, it can be seen that the separators in Examples 1 and 2 of this application can effectively reduce the DC internal resistance of the batteries.
[0081] When the separators obtained in Examples 1, 2, 1, and 2 are applied to ternary high-nickel batteries, the number of cycle times when the battery capacity decays to 80% are 1468, 1307, 967, and 844, respectively. This demonstrates that using the separators in Examples 1 and 2 of this application can guarantee a higher number of battery cycle times and ensure better charge / discharge performance.
[0082] When the separators obtained in Examples 1, 2, 1, and 2 are applied in ternary high-nickel batteries, the battery charge retention rates after 120 days of energy storage are 90%, 88%, 81%, and 75%, respectively. This demonstrates that using the separators in Examples 1 and 2 of this application can ensure that the battery has a stronger energy storage capacity.
[0083] Secondly, embodiments of this application provide an electrode assembly. (See reference...) Figure 4 , Figure 5 , Figure 6 As shown, the electrode assembly includes a positive electrode 2, a negative electrode 3, and a separator 1 as described in the first aspect. The positive electrode 2 and the negative electrode 3 are respectively disposed on both sides of the separator 1.
[0084] For a specific structure of the electrode assembly, please refer to [reference needed]. Figure 5 As shown, in the separator 1, solid electrolyte layers 112 are respectively disposed on both sides of the base membrane 111, and the base membrane 111 and the two solid electrolyte layers 112 constitute the structural layer 11. An adhesive layer 12 is coated on both sides of the structural layer 11, and the adhesive layer 12 includes multiple cold-pressed adhesive particles 121 distributed in a dot matrix. The positive electrode 2 and the negative electrode 3 are respectively attached to both sides of the separator 1.
[0085] For a specific structure of the electrode assembly, please refer to [reference needed]. Figure 6As shown, in the separator 1, a solid electrolyte layer 112 is disposed on one side of the base membrane 111, and a ceramic layer 113 is disposed on the other side. The base membrane 111, the solid electrolyte layer 112, and the ceramic layer 113 constitute a structural layer 11. An adhesive layer 12 is coated on both sides of the structural layer 11, and the adhesive layer 12 includes a plurality of cold-pressed adhesive particles 121 distributed in a lattice. The positive electrode 2 is attached to the side of the separator 1 with the solid electrolyte layer 112, and the negative electrode 3 is attached to the side of the separator 1 with the ceramic layer 113.
[0086] For a specific structure of the electrode assembly, please refer to [reference needed]. Figure 7 As shown, in the separator 1, a solid electrolyte layer 112 is disposed on one side of the base membrane 111, and the base membrane 111 and the solid electrolyte layer 112 constitute a structural layer 11. An adhesive layer 12 is coated on both sides of the structural layer 11, and the adhesive layer 12 includes a plurality of cold-pressed adhesive particles 121 distributed in a lattice. A positive electrode 2 is attached to the side of the separator 1 with the solid electrolyte layer 112, and a negative electrode 3 is attached to the other side of the separator 1.
[0087] The electrode assembly described in this application embodiment may include at least the following advantages:
[0088] The electrode assembly described in this application uses the separator 1 as described in the first aspect. Since the separator 1 uses cold-pressed adhesive pads 121 instead of the hot-pressed adhesive in the prior art, the electrode assembly can utilize a cold-pressing process to bond the separator 1 to the positive electrode 2 and the negative electrode 3. This avoids introducing a hot-pressing process during production, which helps reduce the production and processing costs of the electrode assembly and ensures its safety performance. Multiple cold-pressed adhesive pads 121 are provided in a dot matrix distribution, which can reduce the distribution area of the cold-pressed adhesive pads 121 on the surface of the structural layer 11 while ensuring bonding effectiveness. This reduces the coverage of the adhesive layer 12 on the structural layer 11, allowing most of the micropores in the structural layer 11 to be open outside the adhesive layer 12, thereby increasing the permeability of the separator 1, reducing the impedance of the separator 1, and ensuring efficient lithium-ion conduction in the separator 1. This ensures that the impedance of the electrode assembly will not increase due to the influence of the cold-pressed adhesive.
[0089] Thirdly, embodiments of this application propose a battery, which includes the electrode assembly described in the second aspect. The battery described in this application can be a single cell or a battery pack formed by combining several single cells.
[0090] The battery described in this application embodiment may include at least the following advantages:
[0091] The electrode assembly described in this application embodiment adopts the electrode assembly described in the second aspect. Since the separator 1 in the electrode assembly utilizes cold-pressed adhesive 121 instead of the hot-pressed adhesive in the prior art, the electrode assembly can utilize a cold-pressing process to bond the separator 1 to the positive electrode 2 and the negative electrode 3. This avoids introducing a hot-pressing process during production, which helps reduce the production and processing costs of the electrode assembly and ensures the safety performance of the electrode assembly, thus helping to reduce the production and processing costs of the battery and ensure the safety performance of the battery.
[0092] Multiple cold-pressed adhesive clusters 121 are arranged in a dot matrix pattern, which can reduce the distribution area of the cold-pressed adhesive clusters 121 on the surface of the structural layer 11 while ensuring the bonding effect. This reduces the coverage of the adhesive layer 12 on the structural layer 11, allowing most of the micropores in the structural layer 11 to be open outside the adhesive layer 12, thereby increasing the air permeability of the separator 1, reducing the impedance of the separator 1, and ensuring efficient conduction of lithium ions in the separator 1. This ensures that the impedance of the electrode assembly will not increase due to the cold-pressed adhesive, thereby reducing the DC internal resistance of the battery.
[0093] Fourthly, embodiments of this application provide an electrical device that includes a battery as described in the third aspect.
[0094] Specifically, the electrical equipment described in this application embodiment can be a vehicle. For example, in this application embodiment, the vehicle may include a small car, a medium-sized car, a sedan, a truck, a trailer, a CDV (Car Derived Van), an MPV (Multi-Purpose Vehicle), an SUV (Sport Utility Vehicle), etc. The specific type of vehicle is not limited in this application embodiment.
[0095] Alternatively, the electronic products described in this application embodiment can also be one of the three major categories: computers, communication devices, and consumer electronics. Specifically, they can be laptops, desktop computers, tablets, computer accessories, etc.; they can also be smartphones, smartwatches, walkie-talkies, etc.; or they can be televisions, audio equipment, cameras, game consoles, etc.
[0096] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0097] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.
Claims
1. A diaphragm, characterized in that, include: A structural layer (11) includes a base film (111) and a solid electrolyte layer (112), wherein the solid electrolyte layer (112) is disposed on at least one side of the base film (111); The adhesive layer (12) has two layers and is respectively disposed on both sides of the structural layer (11). The adhesive layer (12) includes a plurality of cold-pressed adhesive balls (121) which are distributed in a dot matrix pattern.
2. The diaphragm according to claim 1, characterized in that, The coating radius of the cold-pressed colloid (121) is a, where 0 cm < a ≤ 0.5 cm.
3. The diaphragm according to claim 1, characterized in that, The interval between two adjacent cold-pressed colloids (121) is b, where 0cm < b ≤ 1cm.
4. The diaphragm according to claim 1, characterized in that, The thickness of the adhesive layer (12) is c, where 0.5μm≤c≤10μm.
5. The diaphragm according to claim 1, characterized in that, The thickness of the solid electrolyte layer (112) is d, 0.5μm≤d≤10μm.
6. The diaphragm according to claim 1, characterized in that, The solid electrolyte particles in the solid electrolyte layer (112) have a particle size of e, where 0.1 μm ≤ e ≤ 3 μm.
7. The diaphragm according to any one of claims 1-6, characterized in that, The structural layer (11) further includes a ceramic layer (113), which is disposed on the side of the base film (111) opposite to the solid electrolyte layer (112).
8. The diaphragm according to claim 7, characterized in that, The thickness of the ceramic layer (113) is f, where 0.5μm≤f≤10μm.
9. The diaphragm according to claim 7, characterized in that, The ceramic particles in the ceramic layer (113) have a particle size of g, where 0.1μm≤g≤3μm.
10. An electrode assembly, characterized in that, It includes a positive electrode (2), a negative electrode (3) and a separator (1) as described in any one of claims 1-9; the positive electrode (2) and the negative electrode (3) are respectively disposed on both sides of the separator (1).
11. A battery, characterized in that, Includes the electrode assembly as described in claim 10.
12. An electrical appliance, characterized in that, Includes the battery as described in claim 11.