Battery separator and battery

Abstract

The application discloses a battery diaphragm and a battery, and the battery diaphragm comprises a diaphragm base material layer, a liquid absorbing layer and a glue coating layer, the liquid absorbing layer is arranged between the diaphragm base material layer and the glue coating layer, wherein the liquid absorbing layer comprises a liquid absorbing structure layer, the liquid absorbing structure layer is provided with a plurality of liquid absorbing holes, and at least one of the liquid absorbing holes is filled with a film forming agent. The battery diaphragm of the application can absorb more electrolyte by arranging a plurality of liquid absorbing holes on the liquid absorbing structure layer of the liquid absorbing layer, thereby improving the liquid absorbing capacity of the battery diaphragm, improving the liquid retaining capacity of the battery diaphragm, and further improving the electrical performance of the battery. Meanwhile, the at least one liquid absorbing hole is filled with the film forming agent, so that the battery diaphragm provided with the film forming agent can form more stable solid electrolyte interface films and positive electrolyte interface films in the cycle process of the battery.

Description

Technical Field

[0001] This invention relates to the field of battery separator technology, specifically to a battery separator and a battery. Background Technology

[0002] In order to improve the full-charge interface effect of the positive and negative electrode plates, the lithium battery industry uses coated separators. In related technologies, when the battery uses double-sided coated separators, the positive and negative electrode plates of the cell have a good bonding effect, but the overall liquid absorption capacity of the battery will be weakened, which will reduce the liquid retention capacity of the battery and thus affect the battery's electrical performance. Summary of the Invention

[0003] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention proposes a battery separator and a battery, wherein the battery separator can absorb more electrolyte, thereby improving the electrical performance of the battery.

[0004] According to an embodiment of the present invention, a battery separator includes: a separator substrate layer, an absorbent layer, and an adhesive layer, wherein the absorbent layer is sandwiched between the separator substrate layer and the adhesive layer, and the absorbent layer includes an absorbent structure layer, the absorbent structure layer is provided with a plurality of absorbent pores, and at least one of the absorbent pores is filled with a film-forming agent.

[0005] According to the battery separator of the present invention, by providing multiple liquid absorption pores on the liquid absorption structure layer of the liquid absorption layer, the liquid absorption layer can absorb more electrolyte, thereby improving the liquid absorption capacity of the battery separator and its liquid retention capacity, and thus improving the electrical performance of the battery. At the same time, a film-forming agent is filled in at least one liquid absorption pore, so that the battery separator with film-forming agent can form a more stable solid electrolyte interface film and positive electrode electrolyte interface film during battery cycling.

[0006] According to some embodiments of the battery separator of the present invention, the liquid-absorbing layer further includes a liquid-absorbing material layer, which covers the outside of the liquid-absorbing structure layer and is adapted to block the opening of the liquid-absorbing hole.

[0007] According to some embodiments of the present invention, the thickness of the liquid-absorbing material layer in the battery separator is D1, and satisfies: 1μm≤D1≤2μm.

[0008] According to some embodiments of the battery separator of the present invention, the liquid-absorbing structural layer is a porous ceramic material.

[0009] According to some embodiments of the present invention, the porous ceramic material of the battery separator has a particle size of 0.1-10 μm.

[0010] According to some embodiments of the present invention, the ratio of the sum of the volumes of the plurality of liquid absorption pores to the volume of the porous ceramic material is 20%-80%.

[0011] According to some embodiments of the present invention, the liquid-absorbing layer is bonded to the separator substrate layer.

[0012] According to some embodiments of the present invention, the battery separator has a first side and a second side on both sides in the thickness direction of the separator substrate layer, and the liquid-absorbing layer and the adhesive layer are provided on both the first side and the second side.

[0013] According to some embodiments of the present invention, the battery separator further includes a coating layer sandwiched between the liquid-absorbing layer on the side opposite to the separator substrate layer and the corresponding adhesive layer.

[0014] The present invention also proposes a battery.

[0015] The battery according to an embodiment of the present invention includes the battery separator described in any one of the above embodiments.

[0016] The advantages of the battery and the aforementioned battery separator compared to the prior art are the same, and will not be repeated here.

[0017] Additional aspects and advantages of the 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

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0019] Figure 1 This is a schematic diagram of a battery separator according to some embodiments of the present invention;

[0020] Figure 2 for Figure 1 A partial cross-sectional view of the liquid absorption layer in the middle;

[0021] Figure 3 for Figure 2 A schematic diagram showing that the liquid-absorbing structure layer is filled with a film-forming agent;

[0022] Figure 4 for Figure 2 A schematic diagram of the liquid-absorbing structure layer in the image.

[0023] Figure label:

[0024] Battery separator 100;

[0025] 10 is the diaphragm substrate layer, and 20 is the adhesive coating layer.

[0026] Liquid-absorbing layer 30, liquid-absorbing structure layer 31, liquid-absorbing hole 311, liquid-absorbing material layer 32;

[0027] Coating 40, film-forming agent 50. Detailed Implementation

[0028] Embodiments of the present invention are described in detail below. 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 the present invention, and should not be construed as limiting the present invention.

[0029] The following disclosure provides numerous different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. Additionally, examples of various specific processes and materials are provided in this invention; however, those skilled in the art will recognize the applicability of other processes and / or the use of other materials.

[0030] The following is for reference. Figures 1-4 A battery separator 100 according to an embodiment of the present invention is described.

[0031] like Figures 1-4 As shown, the battery separator 100 according to an embodiment of the present invention includes: a separator substrate layer 10, an absorbent layer 30, and an adhesive layer 20.

[0032] The liquid-absorbing layer 30 is sandwiched between the diaphragm substrate layer 10 and the adhesive layer 20. The liquid-absorbing layer 30 includes a liquid-absorbing structure layer 31, which has a plurality of liquid-absorbing holes 311, and at least one liquid-absorbing hole 311 is filled with a film-forming agent 50.

[0033] Therefore, the liquid-absorbing layer 30 sandwiched between the separator substrate layer 10 and the adhesive layer 20 can absorb more electrolyte, which can improve the performance of the battery separator 100. At the same time, there are multiple liquid-absorbing holes 311 in the liquid-absorbing structure layer 31 of the liquid-absorbing layer 30, and the film-forming agent 50 is filled in at least one liquid-absorbing hole 311, which enables the battery separator 100 to form a more stable electrolyte interface film during battery cycling.

[0034] For example, during the manufacturing of the battery separator 100, the liquid absorption layer 30 and the film-forming agent 50 are first mixed at a high temperature (200℃-500℃) (weight ratio of 1-5:2-10). After mixing, the film-forming agent 50 is located in the liquid absorption pores 311 of the liquid absorption structure layer 31. The resulting battery separator 100 has better liquid absorption capacity, thereby enabling the battery to obtain better electrical performance. At the same time, the film-forming agent 50 can form a more stable solid electrolyte interface film and positive electrode electrolyte interface film during battery cycling, and the film-forming agent 50 can also regulate dendrite deposition.

[0035] Furthermore, the liquid-absorbing layer 30 is sandwiched between the separator substrate layer 10 and the adhesive layer 20. In this way, the separator substrate layer 10 can provide support for the liquid-absorbing layer 30, while the adhesive layer 20 can better ensure the interface flatness of the positive electrode and the negative electrode after the cell is hot-pressed and shaped, improve the full-charge interface of the electrode, and thus further improve the battery's electrical performance.

[0036] According to an embodiment of the present invention, the battery separator 100 has multiple liquid absorption holes 311 provided on the liquid absorption structure layer 31 of the liquid absorption layer 30. This allows the liquid absorption layer 30 to absorb more electrolyte, thereby improving the liquid absorption capacity of the battery separator 100 and its liquid retention capacity, and thus improving the electrical performance of the battery. At the same time, at least one liquid absorption hole 311 is filled with a film-forming agent 50. Thus, the battery separator 100 with the film-forming agent 50 can form a more stable solid electrolyte interface film and positive electrode electrolyte interface film during battery cycling.

[0037] In some embodiments, such as Figures 1-2 As shown, the liquid-absorbing layer 30 also includes a liquid-absorbing material layer 32, which covers the outside of the liquid-absorbing structure layer 31 and is adapted to block the opening of the liquid-absorbing hole 311.

[0038] Therefore, the liquid-absorbing material layer 32 can block the liquid-absorbing holes 311 of the liquid-absorbing structure layer 31, so that the film-forming agent 50 filled in the liquid-absorbing holes 311 is not easy to detach from the liquid-absorbing structure layer 31. Thus, the liquid-absorbing layer 30 sandwiched between the adhesive layer 20 and the separator substrate layer 10 can improve the electrical performance of the battery separator 100.

[0039] For example, the liquid-absorbing material layer 32 is also mixed with the liquid-absorbing structure layer 31 and the film-forming agent 50 at a high temperature (100℃-200℃) (weight ratio 1-5:5-15). The resulting mixture has better liquid absorption performance. At the same time, the liquid-absorbing material layer 32 can block the opening of the liquid absorption hole 311 of the liquid-absorbing structure layer 31, thereby preventing the film-forming agent 50 from falling out of the liquid absorption hole 311.

[0040] In some embodiments, the thickness of the liquid-absorbing material layer 32 is D1, and satisfies: 1μm≤D1≤2μm.

[0041] Therefore, D1 can be D1 = 1 μm, or D1 = 1.5 μm, or D1 = 2 μm. This way, when the liquid absorbent material layer 32 is placed on the outside of the liquid absorbent structure layer 31, it can be made thinner without affecting the performance of the liquid absorbent material layer 32.

[0042] In some embodiments, the liquid-absorbing structural layer 31 is a porous ceramic material.

[0043] Therefore, porous ceramic materials have a stronger liquid absorption capacity. When porous ceramic materials absorb electrolyte, they can absorb more electrolyte than other materials. At the same time, the weight of ceramic materials is also lighter than other materials, making it easier to install the battery separator 100 in the battery.

[0044] For example, porous ceramic materials can be made of materials such as silicon dioxide, silicon carbide, aluminosilicate, high-silica silicate, boehmite, and alumina. In this way, different types of materials can be selected according to actual application requirements. In some embodiments, the particle size of porous ceramic materials is 0.1-10μm.

[0045] Therefore, the material diameter of 0.1-10μm enables the porous ceramic material to absorb more electrolyte after forming the liquid-absorbing structure layer 31, thereby improving the liquid absorption capacity of the battery separator 100 and also improving the electrical performance of the battery separator 100.

[0046] In some embodiments, the sum of the volumes of the plurality of suction holes 311 is 20%-80% of the volume of the porous ceramic material.

[0047] Therefore, the ratio of the sum of the volumes of the liquid absorption holes 311 to the volume of the porous material is 20%-80%, which enables the porous ceramic material to absorb a sufficient amount of electrolyte when absorbing electrolyte, thereby improving the liquid absorption capacity of the battery separator 100 and thus improving the electrical performance of the battery separator 100.

[0048] For example, in actual use, the ratio of the sum of the volumes of the multiple liquid absorption holes 311 on the porous ceramic material to the volume of the porous ceramic material can be 20%, 50%, or 80%. The ratio of the sum of the volumes of the multiple liquid absorption holes 311 on the porous ceramic material to the volume of the porous ceramic material can be adjusted according to actual use requirements.

[0049] In some embodiments, such as Figure 1 As shown, the liquid-absorbing layer 30 is bonded to the diaphragm substrate layer 10.

[0050] Therefore, when the absorbent layer 30 is bonded to the separator substrate layer 10, the separator substrate layer 10 can provide support for the absorbent layer 30, thereby forming a battery separator 100.

[0051] For example, the separator substrate layer 10 is a conventional separator substrate in the lithium battery industry, while the absorbent layer 30 is first mixed with the adhesive (PVDF, PAA, styrene-butadiene rubber, etc.) in a solvent (NMP, water, etc.) (weight ratio of 1-10:20-40) when it is bonded to the separator substrate layer 10. Only after the mixing is completed is the absorbent layer 30 placed on the separator substrate layer 10 to complete the bonding.

[0052] In some embodiments, such as Figure 1 As shown, the two sides of the membrane substrate layer 10 in the thickness direction are the first side and the second side, respectively. Both the first side and the second side are provided with a liquid absorption layer 30 and an adhesive coating layer 20.

[0053] Therefore, the presence of liquid-absorbing layers 30 on both the first and second sides can further improve the liquid absorption performance of the battery separator 100. At the same time, the presence of adhesive coating layers 20 on both the first and second sides can make the positive and negative electrode sheets of the battery cell more flat after hot pressing and shaping.

[0054] In some embodiments, such as Figure 1 As shown, the battery separator 100 further includes a coating 40, which is sandwiched between the liquid-absorbing layer 30 on the side facing away from the separator substrate layer 10 and the corresponding adhesive layer 20.

[0055] Therefore, the coating 40 can provide a certain degree of protection for the separator substrate layer 10, making it easier to install the battery separator 100 in the battery.

[0056] The present invention also proposes a battery.

[0057] The battery according to an embodiment of the present invention includes the battery separator 100 of any of the above embodiments.

[0058] According to an embodiment of the present invention, in the battery separator 100 thereon, by providing a plurality of liquid absorption holes 311 on the liquid absorption structure layer 31 of the liquid absorption layer 30, the liquid absorption layer 30 can absorb more electrolyte, thereby improving the liquid absorption capacity of the battery separator 100 and improving its liquid retention capacity, thereby improving the electrical performance of the battery. At the same time, at least one liquid absorption hole 311 is filled with a film-forming agent 50, so that the battery separator 100 with film-forming agent 50 can form a more stable solid electrolyte interface film and positive electrode electrolyte interface film during battery cycling.

[0059] The following describes some embodiments of the battery separator 100 of the present invention:

[0060] In some embodiments, the porous ceramic material is selected from porous boehmite with a particle size of 0.5 μm and a micropore content of 40%. The porous ceramic material is mixed with a film-forming agent (alkaline earth metal oxyacid salt) at a weight ratio of 5:7 at a high temperature of 280°C. The resulting porous ceramic mixture is mixed with a copolymer polyacrylate at a weight ratio of 2:8 at a temperature of 180°C (the copolymer polyacrylate layer thickness is 0.2 μm). The porous ceramic mixture obtained in the previous step is mixed with a PVDF binder at a weight ratio of 3:7 in an NMP solution. The resulting porous ceramic and binder mixture is sprayed onto a diaphragm substrate with a substrate thickness of 11 μm (double-sided spraying) to a thickness of 2 μm; this is coating layer one. A 2 μm adhesive layer (PVDF adhesive layer) is then coated onto the surface of coating layer one to obtain a novel double-sided adhesive-coated diaphragm.

[0061] A 6Ah ternary lithium battery cell (model 6575115) was prepared. The cell separator used was the novel separator prepared above. The positive electrode, negative electrode, and electrolyte were conventional materials. The comparative example also used a 6Ah ternary lithium battery cell (model 6575115), employing a conventional double-sided coated separator (the separator substrate was the same as the novel separator, the ceramic layer was ordinary ceramic, the coating thickness was the same as the novel separator, and the adhesive layer was the same as the novel separator), with all other materials being the same. Performance tests were conducted on the batteries from Example 1 and Comparative Example 1, and the performance comparison is shown in Table 1.

[0062] Table 1

[0063]

[0064] As can be seen from the comparison of the embodiments and comparative examples, the battery made with the novel separator of the present invention has significantly improved liquid absorption performance and electrical performance compared with the battery made with ordinary double-sided coated separator.

[0065] In some embodiments, the porous ceramic material selected is a porous silica ceramic material with a particle size of 0.8 μm and a micropore content of 60%. The porous ceramic material is mixed with a film-forming agent (alkali metal oxyacid salt) at a weight ratio of 3:8 at a high temperature of 300°C. The resulting porous ceramic mixture is then mixed with a copolymer polyacrylate at a weight ratio of 2:8 at a temperature of 180°C (the copolymer polyacrylate layer thickness is 0.2 μm). The porous ceramic mixture obtained in the previous step is then mixed with a PVDF binder at a weight ratio of 3:7 in an NMP solution. The resulting porous ceramic and binder mixture is sprayed onto a 9 μm membrane substrate (double-sided spraying) with a thickness of 2 μm; this is the first coating. A 2 μm adhesive layer (PVDF adhesive layer) is then coated onto the surface of the first coating. This yields a novel double-sided adhesive-coated separator.

[0066] A 14Ah ternary lithium battery cell (model 7082140) was prepared. The cell separator used was the novel separator prepared above. The positive electrode, negative electrode, and electrolyte were conventional materials. The comparative example also used a 14Ah ternary lithium battery cell (model 7082140), employing a conventional double-sided coated separator (the separator substrate was the same as the novel separator, the ceramic layer was ordinary ceramic, the coating thickness was the same as the novel separator, and the adhesive layer was the same as the novel separator), with all other materials being the same. Performance tests were conducted on the batteries from Example 2 and Comparative Example 2, and the performance comparison is shown in Table 2 below.

[0067] Table 2

[0068]

[0069] As can be seen from the comparison of the embodiments and comparative examples, the battery made with the novel separator of the present invention has significantly improved liquid absorption performance and electrical performance compared with the battery made with ordinary double-sided coated separator.

[0070] In some embodiments, the porous ceramic material is selected from high-silica silicate materials with a particle size of 1 μm and a micropore content of 50%. The porous ceramic material is mixed with a transition metal (oxyacid salt) at a weight ratio of 4:7 at a high temperature of 300°C. The resulting porous ceramic mixture is mixed with a copolymer polyacrylate at a weight ratio of 2:8 at a temperature of 180°C (the copolymer polyacrylate layer thickness is 0.2 μm). The porous ceramic mixture obtained in the previous step is mixed with a PVDF binder at a weight ratio of 2:6 in an NMP solution. The resulting porous ceramic and binder mixture is sprayed onto a diaphragm substrate with a substrate thickness of 11 μm (double-sided spraying) to a thickness of 2 μm; this is coating layer one. A 1.5 μm adhesive layer (PVDF adhesive layer) is then coated onto the surface of coating layer one. This yields a novel double-sided adhesive-coated diaphragm.

[0071] A 5Ah ternary lithium battery cell (model 5580100) was prepared. The cell separator used was the novel separator prepared above. The positive electrode, negative electrode, and electrolyte were conventional materials. The comparative example also used a 5Ah ternary lithium battery cell (model 5580100), employing a conventional double-sided coated separator (the separator substrate was the same as the novel separator, the ceramic layer was ordinary ceramic, the coating thickness was the same as the novel separator, and the adhesive layer was the same as the novel separator), with all other materials being the same. Performance tests were conducted on the batteries of Example 3 and Comparative Example 3, and the performance comparisons are shown in Table 3.

[0072] Table 3

[0073]

[0074] As can be seen from the comparison of the embodiments and comparative examples, the battery made with the novel separator of the present invention has significantly improved liquid absorption performance and electrical performance compared with the battery made with ordinary double-sided coated separator.

[0075] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0076] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0077] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0078] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0079] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "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. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0080] Although embodiments of the 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 invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A battery separator (100), characterized in that, include: Diaphragm substrate layer (10); The liquid-absorbing layer (30) and the adhesive layer (20) are sandwiched between the diaphragm substrate layer (10) and the adhesive layer (20); The liquid-absorbing layer (30) includes a liquid-absorbing structure layer (31), which has a plurality of liquid-absorbing holes (311), and at least one of the liquid-absorbing holes (311) is filled with a film-forming agent (50); the liquid-absorbing structure layer (31) is a porous ceramic material.

2. The battery separator (100) according to claim 1, characterized in that, The liquid-absorbing layer (30) further includes a liquid-absorbing material layer (32), which covers the outside of the liquid-absorbing structure layer (31) and is adapted to block the opening of the liquid-absorbing hole (311).

3. The battery separator (100) according to claim 2, characterized in that, The thickness of the liquid-absorbing material layer (32) is D1, and satisfies: 1μm≤D1≤2μm.

4. The battery separator (100) according to claim 1, characterized in that, The porous ceramic material has a particle size of 0.1-10 μm.

5. The battery separator (100) according to claim 1, characterized in that, The sum of the volumes of the plurality of liquid absorption holes (311) is 20%-80% of the volume of the porous ceramic material.

6. The battery separator (100) according to claim 1, characterized in that, The liquid-absorbing layer (30) is bonded to the diaphragm substrate layer (10).

7. The battery separator (100) according to any one of claims 1-6, characterized in that, The membrane substrate layer (10) has a first side and a second side on both sides in the thickness direction, and the first side and the second side are provided with the liquid absorption layer (30) and the adhesive layer (20).

8. The battery separator (100) according to claim 7, characterized in that, It also includes a coating (40), which is sandwiched between the liquid-absorbing layer (30) on the side away from the diaphragm substrate layer (10) and the corresponding adhesive layer (20).

9. A battery, characterized in that, Includes the battery separator (100) according to any one of claims 1-8.

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