Diaphragm, battery roll core and battery

Abstract

The utility model relates to the technical field of lithium ion batteries, in particular to a diaphragm, a battery roll core and a battery. The diaphragm comprises a base film and a coating layer, the base film is provided with a plurality of spraying areas, each spraying area comprises two edge areas and a center area arranged between the two edge areas, the edge areas are arranged on the two opposite sides of the spraying areas in the width direction respectively, and the edge areas of every two adjacent spraying areas are connected; the coating layer covers the spraying area, and the thickness of the coating layer in the central area is larger than the thickness of the coating layer in the edge area. The utility model aims to solve the problem that lithium is separated out on the surface of the lithium ion battery in the use process due to non-uniform distribution of a coating layer of a diaphragm in the prior art.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium ion batteries, in particular to a diaphragm, a battery coil and a battery. Background Art

[0002] In the manufacturing process of lithium-ion batteries, the separator is an important component used to separate the positive and negative electrodes, prevent direct electronic short circuits, and allow lithium ions to be transmitted in the battery. Spraying separators are mainly used to prepare the separator layer in lithium-ion batteries. The coating layer usually uses polymer materials such as PVDF (polyvinylidene fluoride).

[0003] The existing fast-charging lithium battery designs basically use a spraying technology with uniform thickness distribution. The coating layer sprayed by this spraying process easily leads to uneven distribution of PVDF or ceramic on the surface of the diaphragm, which causes pore blockage during the recycling process of the lithium battery, seriously affecting the transmission of lithium ions, and thus causing the problem of lithium deposition on the negative electrode surface of the battery cell. Utility Model Content

[0004] The technical problem to be solved by the embodiments of the utility model is to provide a diaphragm, a battery core and a battery to solve the problem of uneven distribution of the coating layer of the diaphragm in the prior art, which leads to surface lithium deposition in the lithium-ion battery during use.

[0005] In the first aspect, the utility model discloses a diaphragm, comprising: a base film and a coating layer, the base film having a plurality of spraying areas, the spraying areas comprising two edge areas and a central area arranged between the two edge areas, the edge areas being arranged on opposite sides of the width direction of the spraying areas, respectively, and the edge areas of two adjacent spraying areas being connected; the coating layer covers the spraying areas, and the thickness of the coating layer in the central area is greater than the thickness of the coating layer in the edge area.

[0006] Optionally, the coating layer is polyvinylidene fluoride or ceramic.

[0007] Optionally, the width of the spraying area ranges from 4 mm to 180 mm.

[0008] Optionally, the thickness of a single coating layer ranges from 0.5um to 3um.

[0009] Optionally, a plurality of the spraying areas are sequentially connected to cover one side of the base film.

[0010] Optionally, the coating layer smoothly transitions from the central area to the edge area.

[0011] In the second aspect, the utility model also discloses a battery roll core, comprising a positive electrode sheet, a negative electrode sheet, and the separator of any one of the above items, wherein the positive electrode sheet, the negative electrode sheet and the separator are wound and the separator is located between the positive electrode sheet and the negative electrode sheet.

[0012] Optionally, the battery roll core has an inner side and an outer side, and the coating layer is disposed on the inner side.

[0013] In a third aspect, the utility model further discloses a battery, which includes the battery coil core in the second aspect.

[0014] Compared with the prior art, the beneficial effects of the diaphragm, battery roll core and battery provided by the embodiments of the utility model are: a number of spraying areas are set on the base film, and the spraying area is divided into an edge area and a center area, so that the difference in coating thickness in different areas can be achieved. This design can achieve a higher coating thickness in a specific area, thereby providing better isolation and protection effects. The thickness of the coating layer in the center area is greater than the thickness in the edge area, so that the coating layer in the center area can provide a better isolation effect. By changing the thickness of the coating layer in different areas, the barrier ability of the coating layer to the external environment can be enhanced, and the transmission of lithium ions is not affected, so that the lithium battery can avoid the problem of pore blockage during the cycle use, reduce the occurrence of lithium plating problems on the negative electrode surface of the battery cell, and improve the performance and life of the diaphragm. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The technical solution of the utility model will be further described in detail below with reference to the accompanying drawings and embodiments, in which:

[0016] Figure 1 is a front view of a diaphragm provided in an embodiment of the utility model;

[0017] Figure 2 for Figure 1 Schematic diagram of the diaphragm shown from another angle.

[0018] The reference numerals in the figures are:

[0019] 1000, diaphragm; 100, base film; 101, spraying area; 1011, edge area; 1012, center area; 200, coating layer. DETAILED DESCRIPTION

[0020] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. Now, in conjunction with the accompanying drawings, a preferred embodiment of the present utility model is described in detail.

[0021] The utility model embodiment provides a diaphragm 1000, such as Figure 1 and Figure 2As shown, the diaphragm 1000 includes: a base film 100 and a coating layer 200, the base film 100 has a plurality of spraying areas 101, the spraying area 101 includes two edge areas 1011, and a central area 1012 arranged between the two edge areas 1011, the edge areas 1011 are respectively arranged on opposite sides of the width direction of the spraying area 101, and the edge areas 1011 of two adjacent spraying areas 101 are connected; the coating layer 200 covers the spraying area 101, and the thickness of the coating layer 200 in the central area 1012 is greater than the thickness of the coating layer 200 in the edge area 1011.

[0022] A plurality of spraying areas 101 are arranged on the base film 100, and the spraying area 101 is divided into an edge area 1011 and a central area 1012, so that the thickness difference of the coating layer 200 in different areas can be achieved. This design can achieve a higher thickness of the coating layer 200 in a specific area, thereby providing better isolation and protection effects. The thickness of the coating layer 200 in the central area 1012 is greater than the thickness of the edge area 1011, so that the coating layer 200 in the central area 1012 can provide a better isolation effect. By changing the thickness of the coating layer 200 in different areas, the barrier ability of the coating layer 200 to the external environment can be enhanced, and the transmission of lithium ions is not affected, so that the lithium battery can avoid the problem of pore blockage during the cycle use, reduce the occurrence of lithium plating problems on the negative electrode surface of the battery cell, and improve the performance and life of the diaphragm 1000.

[0023] Specifically, the edge areas 1011 of adjacent spraying areas 101 are connected, which can ensure the continuity and consistency of the coating layer 200 , enhance the integrity of the coating layer 200 , and improve the overall performance and reliability of the diaphragm 1000 .

[0024] In an optional embodiment of the present invention, the coating layer 200 is polyvinylidene fluoride or ceramic.

[0025] The coating layer 200 uses polyvinylidene fluoride or ceramic material, which can further enhance the performance and durability of the diaphragm 1000. Polyvinylidene fluoride (PVDF) is a high-performance polymer material with excellent chemical corrosion resistance, high temperature resistance and weather resistance. Using PVDF as the coating layer 200 can provide the diaphragm 1000 with better chemical stability and durability, enabling it to operate for a long time under harsh environmental conditions. In addition, PVDF also has good anti-adhesion properties, which can reduce the adsorption of impurities and improve the efficiency and reliability of the diaphragm 1000.

[0026] Ceramic materials have excellent wear resistance, corrosion resistance and high temperature stability. Using ceramic as coating layer 200 can increase the hardness and durability of diaphragm 1000, making it resistant to physical wear and chemical erosion. Ceramic coating layer 200 can also provide additional thermal insulation performance, reduce heat conduction, and thus improve the insulation performance of diaphragm 1000.

[0027] By using PVDF or ceramic as the coating layer 200 material, the chemical corrosion resistance, high temperature resistance, wear resistance, and insulation performance of the diaphragm 1000 may be enhanced.

[0028] In an optional embodiment of the present invention, the width of the spraying area 101 ranges from 4 mm to 180 mm, and the thickness of a single coating layer 200 ranges from 0.5 um to 3 um.

[0029] The width of the spray area 101 ranges from 4mm to 180mm, providing flexibility and adjustability. This means that spray areas 101 of different widths can be selected according to specific needs to meet the requirements of different application scenarios. Narrower spray areas 101 are suitable for small devices or delicate parts, while wider spray areas 101 are suitable for large devices or more extensive coating needs.

[0030] The thickness of a single coating layer 200 ranges from 0.5um to 3um, and the coating layer 200 gradually becomes thicker from the edge area 1011 to the center area 1012. By changing the thickness of the coating layer 200 in different areas, the lithium battery can avoid the problem of pore blockage during recycling, reduce the occurrence of lithium plating on the negative electrode surface of the battery cell, and improve the performance and life of the diaphragm 1000.

[0031] On the other hand, the coating layer 200 has a larger thickness range, so that the coating layer 200 can have better adjustability, so that the appropriate thickness of the coating layer 200 can be selected according to the requirements of different applications.

[0032] Specifically, increasing the thickness of the coating layer 200 in the central area 1012 can provide a higher isolation effect and protection capability. At the same time, using a thinner coating layer 200 in the edge area 1011 can improve sensitivity and response speed. This optimization can make the diaphragm 1000 more adaptable to different application requirements and provide better performance.

[0033] refer to Figure 1 and Figure 2 , a plurality of spraying areas 101 are sequentially connected to cover one side of the base film 100 .

[0034] The spraying area 101 sequentially connects and covers one side of the base film 100, ensuring the connectivity and consistency of the coating layer 200. This means that the coating layer 200 forms a continuous coating layer 200 on the entire surface of the base film 100 without gaps or breaks. Better consistency and connectivity can improve the integrity and stability of the diaphragm 1000, prevent the coating layer 200 from peeling off or being damaged during use, and the integrated coating layer 200 can provide a more stable isolation and protection effect, while improving the reliability and performance consistency of the diaphragm 1000.

[0035] refer to Figure 2 The coating layer 200 smoothly transitions from the central area 1012 to the edge area 1011 .

[0036] Through the smooth transition, the coating layer 200 forms a uniform coverage between the central area 1012 and the edge area 1011. This uniformity can ensure that the coating layer 200 maintains the continuity of the coating layer 200, avoids breaks or gaps, and improves the integrity and stability of the diaphragm 1000.

[0037] Specifically, the coating layer 200 smoothly transitions from the central area 1012 to the edge area 1011, gradually reducing thickness or changing properties. This progressive design can adapt the coating layer 200 to the needs of different regions. For example, the central area 1012 may require a thicker coating layer 200 to provide a higher isolation effect, while the edge area 1011 may require a thinner coating layer 200 to improve sensitivity or adapt to specific application requirements. The gradual transition allows the coating layer 200 to adapt to the functional requirements of different regions.

[0038] The embodiment of the utility model further provides a battery roll core, which includes a positive electrode sheet, a negative electrode sheet, and the separator 1000 in the aforementioned embodiment. The positive electrode sheet, the negative electrode sheet and the separator 1000 are wound and arranged, and the separator 1000 is located between the positive electrode sheet and the negative electrode sheet.

[0039] The battery roll core includes the same structure and benefits as the separator 1000 in the previous embodiment. The structure and benefits of the separator 1000 have been described in detail in the previous embodiment and will not be repeated here.

[0040] In an optional embodiment of the present invention, the battery roll core has an inner side and an outer side, and the coating layer 200 is disposed on the inner side.

[0041] The coating layer 200 is located on the inner side of the battery core and can provide isolation and protection for the battery core. The coating layer 200 can prevent other active materials in the battery core from contacting the external environment, reducing battery loss and corrosion. This isolation and protection effect can improve the stability and life of the battery core.

[0042] Placing the coating layer 200 on the inner side of the battery roll core can improve the volumetric efficiency of the battery. By placing the coating layer 200 on the inner side, the space of the battery roll core can be maximized, reducing the impact of the coating layer 200 on the overall size of the battery roll core. This helps to improve the energy density and power density of the battery roll core.

[0043] An embodiment of the utility model further provides a battery, the battery comprising the battery coil core in the aforementioned embodiment.

[0044] The battery comprises the same structure and benefits as the battery roll core in the previous embodiment. The structure and benefits of the battery roll core have been described in detail in the previous embodiment and will not be repeated here.

[0045] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present utility model rather than to limit it. For those skilled in the art, the technical solutions described in the above embodiments can be modified, or some of the technical features therein can be replaced by equivalents; and all these modifications and replacements should fall within the scope of protection of the claims attached to the present utility model.

Claims

1. A diaphragm, characterized in that: include: A base film, wherein the base film has a plurality of spraying areas, the spraying area includes two edge areas and a central area arranged between the two edge areas, the edge areas are arranged at opposite sides of the spraying area in a width direction, and the edge areas of two adjacent spraying areas are connected; A coating layer covers the spraying area, and a thickness of the coating layer in the central area is greater than a thickness of the coating layer in the edge area.

2. The diaphragm according to claim 1, characterized in that The coating layer is polyvinylidene fluoride or ceramic.

3. The diaphragm according to claim 1 or 2, characterized in that: The width of the spraying area ranges from 4 mm to 180 mm.

4. The diaphragm according to claim 1 or 2, characterized in that: The thickness of a single coating layer ranges from 0.5um to 3um.

5. The diaphragm according to claim 1 or 2, characterized in that: A plurality of the spraying areas are sequentially connected to cover one side of the base film.

6. The diaphragm according to claim 1 or 2, characterized in that: The coating layer smoothly transitions from the central area to the edge area.

7. A battery roll core, characterized in that: It comprises a positive electrode sheet, a negative electrode sheet, and the separator according to any one of claims 1 to 6, wherein the positive electrode sheet, the negative electrode sheet and the separator are wound and the separator is located between the positive electrode sheet and the negative electrode sheet.

8. The battery roll core according to claim 7, characterized in that: The battery roll core has an inner side and an outer side, and the coating layers are all arranged on the inner side.

9. A battery, characterized in that: The invention comprises the battery roll core as claimed in claim 7 or 8.

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