Positive electrode sheet, method for producing same, and lithium ion battery

Abstract

The application discloses a positive plate, a preparation method of the positive plate, and a lithium ion battery. The positive plate comprises a current collector and a plurality of tabs connected with the current collector; an active material layer is arranged on a first side of the current collector; a plurality of insulation areas are arranged at a first end of the active material layer, and the first end is close to the plurality of tabs; and the plurality of insulation areas are arranged at intervals and correspond to positions of the plurality of tabs one by one. The arrangement of the insulation areas at positions corresponding to the positions of the plurality of tabs can avoid short circuit of the battery and improve the safety of the tabs.

Description

Technical Field

[0001] This application belongs to the field of lithium-ion batteries, specifically relating to a positive electrode sheet and its preparation method, as well as a lithium-ion battery. Background Technology

[0002] Lithium-ion batteries, as energy storage devices, are widely used in electronic products, electric vehicles, energy storage and other fields. Among them, the consumer electronics market is stable and mature, with steady growth every year. Electric vehicles, as a market with rapid production growth this year, belong to the sunrise industry in the new energy sector.

[0003] In the manufacturing process of lithium-ion batteries, insulating tape or ceramic materials are placed at the tabs to reduce the safety hazard of short circuits in the positive electrode. However, the adhesion of the insulating tape is uncontrollable; once it detaches and enters the electrolyte, it loses its protective function and contaminates the electrolyte, affecting the battery's cycle performance and safety. Ceramic materials, on the other hand, are inherently hard and rigid, easily damaging the electrode. Therefore, providing a positive electrode and corresponding lithium-ion battery that can both prevent short circuits in the tabs and improve safety is an urgent problem to be solved. Summary of the Invention

[0004] To address the aforementioned technical problems, this application provides a positive electrode sheet, a method for preparing the same, and a lithium-ion battery including the positive electrode sheet. An active material layer is disposed on the first side of the current collector of the positive electrode sheet. Multiple insulating regions are disposed on the first end of the active material layer near the multiple tabs. These insulating regions are spaced apart and correspond one-to-one with the positions of the multiple tabs. Distributing insulating regions at positions corresponding to the multiple tabs can prevent battery short circuits and improve the safety of the tabs.

[0005] A first aspect of this application provides a positive electrode plate, the positive electrode plate comprising:

[0006] A current collector and multiple tabs connected to the current collector;

[0007] An active material layer is disposed on the first side of the current collector;

[0008] Multiple insulating regions are disposed on a first end of the active material layer, the first end being close to the multiple electrodes; the multiple insulating regions are spaced apart and correspond one-to-one with the positions of the multiple electrodes.

[0009] In some embodiments, the distance between the two sides of the insulating region and the two sides corresponding to the tab is greater than or equal to a preset distance.

[0010] In some embodiments, the width of the first end is greater than or equal to a preset width.

[0011] In some embodiments, the positive electrode sheet further includes an insulating coating applied to the surfaces of the plurality of tabs.

[0012] In some embodiments, the insulating material of the insulating coating on the surface of the tab is the same as the insulating material of the insulating region.

[0013] In some embodiments, the insulating material of the insulating region comprises the following components, expressed as a percentage by weight:

[0014]

[0015] In some embodiments, the insulating material of the insulating region comprises the following components, expressed as a percentage by weight:

[0016]

[0017] In some embodiments, the additive is selected from at least one of ethyl 4-dimethylaminobenzoate and 2-isopropylthioxanthrone.

[0018] In some embodiments, the mass percentage of the ethyl 4-dimethylaminobenzoate is 1 to 2%.

[0019] In some embodiments, the 2-isopropylthioxanthone has a mass percentage of 1 to 2%.

[0020] In some embodiments, the material of the active material layer is a positive electrode active material, which includes one of lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, lithium nickel cobalt manganese oxide, and lithium nickel cobalt aluminum oxide.

[0021] A second aspect of this application provides a method for preparing a positive electrode sheet, the method comprising the following steps:

[0022] Provides a current collector and multiple tabs connected to the current collector;

[0023] An active material layer is disposed on the first side of the current collector.

[0024] Multiple insulating regions are provided on the first end of the active material layer, the first end is close to multiple electrodes, the multiple insulating regions are spaced apart, and their positions correspond one-to-one with the positions of the multiple electrodes.

[0025] In some embodiments, the distance between the two sides of the insulating region and the two sides corresponding to the tab is greater than or equal to a preset distance.

[0026] In some embodiments, the width of the first end is greater than or equal to a preset width.

[0027] In some embodiments, an insulating coating is applied to the surfaces of the plurality of tabs.

[0028] In some embodiments, the insulating material of the plurality of insulating regions is the same as the insulating material of the insulating coating on the surface of the tab.

[0029] In some embodiments, the insulating material of the insulating region comprises the following components, expressed as a percentage by weight:

[0030]

[0031] In some embodiments of this application, the insulating material of the insulating region comprises the following components expressed as a weight percentage:

[0032]

[0033] In some embodiments, the additive is selected from at least one of ethyl 4-dimethylaminobenzoate and 2-isopropylthioxanthrone.

[0034] In some embodiments, the mass percentage of the ethyl 4-dimethylaminobenzoate is 1 to 2%.

[0035] In some embodiments, the 2-isopropylthioxanthone has a mass percentage of 1 to 2%.

[0036] In some embodiments, the positive electrode active material includes one of lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, lithium nickel cobalt manganese oxide, and lithium nickel cobalt aluminum oxide.

[0037] In some embodiments, the step of forming a plurality of insulating regions at the first end of the active material layer includes:

[0038] An insulating layer is coated at the first end of the active material layer;

[0039] A mask layer is disposed on the insulating layer, and the mask layer has a preset pattern;

[0040] The insulating layer is etched according to the preset pattern to form a plurality of insulating regions;

[0041] Remove the mask layer.

[0042] A third aspect of this application provides a lithium-ion battery, the lithium-ion battery comprising a negative electrode, a separator, and the positive electrode provided in this application.

[0043] The beneficial effects of this application include, but are not limited to: This application provides a positive electrode sheet and its preparation method, wherein the current collector surface of the positive electrode sheet is coated with an active material layer, and multiple insulating regions are provided on the active material layer near multiple tabs, the multiple insulating regions are spaced apart and correspond one-to-one with the positions of the multiple tabs, and a portion of the active material layer is exposed between two adjacent insulating regions; the provision of insulating regions at positions corresponding to the positions of the multiple tabs can both prevent battery short circuits and improve the safety of the tabs.

[0044] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0045] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments conforming to this application and, together with the specification, serve to explain the technical solutions of this application. The drawings described below are some embodiments of this application, but not all embodiments. Those skilled in the art will be able to obtain other drawings based on these drawings without inventive effort.

[0046] The various objectives, features, and advantages of this application will become more apparent from the following detailed description of embodiments in conjunction with the accompanying drawings. The drawings are merely illustrative illustrations and are not necessarily drawn to scale.

[0047] Figure 1 This is a flowchart illustrating a method for preparing a positive electrode sheet according to one embodiment;

[0048] Figures 2-4 This is a schematic diagram of the structure corresponding to each step in the preparation process of a positive electrode sheet according to an embodiment of this application;

[0049] Figure 5 This is a flowchart illustrating a method for preparing an insulating region according to one embodiment.

[0050] Reference numerals: 1-Active material layer, 2-Current collector, 3-Taper, 4-Insulating region, 5-First end of the active material layer. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be arbitrarily combined with each other.

[0052] This application provides a positive electrode sheet and its preparation method, as well as a lithium-ion battery. (Reference) Figures 1-5 , Figure 1 This is a flowchart illustrating a method for preparing a positive electrode according to an exemplary embodiment; Figure 2 This is a schematic diagram of the current collector and the tab in a method for preparing a positive electrode according to an exemplary embodiment; Figure 3 This is a schematic diagram of the first end of the active material layer in a method for preparing a positive electrode according to an exemplary embodiment; Figure 4 This is a schematic diagram of the insulating region in a method for preparing a positive electrode sheet according to an exemplary embodiment; Figure 5 This is a flowchart illustrating a method for preparing an insulating region according to an exemplary embodiment.

[0053] The following description, with reference to the accompanying drawings, describes an exemplary embodiment of a positive electrode sheet according to this application, such as... Figures 2-4 As shown, the positive electrode sheet of an exemplary embodiment of this application includes:

[0054] Current collector 2 and multiple tabs 3 connected to current collector 2;

[0055] Active material layer 1 is disposed on the first side of current collector 2;

[0056] Multiple insulating regions 4 are disposed on the first end 5 of the active material layer, and the first end 5 is close to multiple tabs 3; the multiple insulating regions 4 are spaced apart and correspond one-to-one with the positions of the multiple tabs 3.

[0057] During the manufacturing process of lithium-ion batteries, when the tabs are bent and welded together, the electrode sheets at the tab position tilt downwards. Short circuits may occur between the tabs and at the first end of the active material layer near the tabs due to potential contact. To avoid this problem, multiple insulating areas are set on the first end of the active material layer near the tabs, which can both prevent battery short circuits and improve the safety of the tabs.

[0058] In the exemplary embodiments provided in this application, an insulating region is provided at a corresponding position on the first end of the active material layer near the electrode tab. The multiple insulating regions are not continuous but are spaced apart and correspond one-to-one with the positions of the multiple electrodes tabs. A portion of the active material layer is exposed between two adjacent insulating regions. The spaced-apart insulating regions can expose more of the active material in the active material layer, so as to utilize the active material more effectively. This not only reduces the risk of short circuits but also avoids the situation where the active material cannot function due to being covered by the insulating layer, thereby effectively improving the energy density.

[0059] In the exemplary embodiments of this application, when the insulating region 4 is located on the first end 5 of the active material layer 1 near the tab 3, it ensures that the tab does not contact the exposed active material layer and is completely separated by the insulating region. This effectively reduces the occurrence of battery short circuits when the tab is bent. The positions of the insulating region 4 and the tab 3 correspond one-to-one. There can be multiple tabs 3 and multiple insulating regions 4. Alternatively, there can be only one tab 3 and one insulating region 4, with the position of the tab 3 corresponding to the position of the insulating region 4.

[0060] In exemplary embodiments of this application, such as Figure 4 As shown, the distance D1 between the two sides of the insulating region 4 and the corresponding two sides of the tab 3 is greater than or equal to a preset distance. To ensure safety during tab bending—that is, to prevent short circuits due to potential contact between tabs or at the first end of the active material layer near the tab—the length of the insulating region corresponding to each tab needs to be greater than the length of the connection between the tab and the current collector, and the length difference must be greater than or equal to a preset length. In other words, the distance between the two sides of each insulating region and the two sides of the corresponding tab needs to be, for example… Figure 4 As shown in the diagram, D1 should be greater than or equal to the preset distance. The preset distance can be set to ensure safety when the tab is bent. Alternatively, the preset distance can be set to ensure safety when the tab is bent while exposing as much of the active material layer between the insulating areas as possible. For example, the preset distance can be 0.5–10 mm, and D1 can be greater than or equal to 0.5–10 mm.

[0061] In the exemplary embodiments of this application, the distance between the two side edges of the insulating region and the two side edges of the corresponding tabs is greater than or equal to a preset distance. This ensures that the length of the insulating region is greater than the length of the connection between the tab and the current collector, preventing the tab from contacting the exposed active material layer and separating it from the insulating region. A sufficiently long insulating region can effectively reduce the occurrence of battery short circuits. The preset distance can be 0.5–10 mm, and the specific value of the preset distance is determined according to actual needs.

[0062] In exemplary embodiments of this application, such as Figure 4As shown, the width W1 of the first end 5 is greater than or equal to a preset width. To ensure safety during tab bending, i.e., to prevent short circuits due to potential contact between tabs or at the first end of the active material layer near the tabs during tab bending, the distance between the two side edges of each insulating area and the two side edges of the corresponding tab is considered, for example... Figure 4 As shown in the diagram, D1, while being greater than or equal to a preset distance, can also be considered to ensure that the width of each insulating region, i.e., the width of the first end of the active material layer near the electrode tab, is greater than or equal to a preset width. The width of each insulating region is the width of the insulating region along the direction away from the electrode tab, such as... Figure 4 The W1 shown is set with a preset width to ensure safety when the tab is bent. The preset width can also be set to ensure safety when the tab is bent while exposing as much of the active material layer between the insulation areas as possible.

[0063] When setting the preset width, a preset distance can be considered. While ensuring that the distance between the two side edges of each insulation zone and the two side edges of the corresponding tab is greater than or equal to the preset distance, setting the preset width as N times the preset distance can more effectively ensure safety when the tab is bent. N is a positive integer greater than or equal to 1. For example, the preset width can be 1-5 times the preset distance, meaning the width W1 of each insulation zone can be greater than or equal to 1-5 times the distance D1 between the two side edges of insulation zone 4 and the corresponding two side edges of tab 3.

[0064] In an exemplary embodiment of this application, the width W1 of the first end of the active material layer near the tab is greater than or equal to a preset width, ensuring sufficient width at the first end to prevent short circuits due to potential contact between the tabs or at the first end of the active material layer near the tab during electrode bending. The preset width can be 1-5 times a preset distance, with the specific value determined according to actual needs. Setting the preset width as N times the preset distance more effectively ensures safety during tab bending.

[0065] The width of the first end of the active material layer near the tab can be set to ensure safety when the tab is bent, while also exposing as much of the active material layer as possible. For example, the preset width and preset distance can be equal, i.e., the preset width is twice the preset distance. This can effectively ensure safety when the tab is bent, while also exposing more of the active material in the active material layer. This allows the active material in the active material layer to be used more effectively, reducing the risk of short circuits, and also avoiding the situation where the active material cannot function due to excessive coverage by the insulating coating.

[0066] In an exemplary embodiment of this application, the positive electrode sheet further includes an insulating coating applied to the surfaces of the plurality of tabs 3. Applying an insulating coating to the tabs 3 can effectively ensure safety when the tabs are bent.

[0067] The insulating material of the insulating coating on the tab surface and the insulating material of the insulating area can be the same or different. When the insulating material of the insulating coating on the tab surface and the insulating material of the insulating area are the same, they can be completed in the same process, saving processing time.

[0068] In an exemplary embodiment of this application, the insulating material of the insulating region comprises the following components expressed as a percentage by weight:

[0069]

[0070]

[0071] In an exemplary embodiment of this application, the insulating material of the insulating region comprises the following components expressed as a percentage by weight:

[0072]

[0073] In an exemplary embodiment of this application, the plurality of insulating regions disposed at the first end of the active material layer can be formed in the following manner:

[0074] An insulating layer is coated on the first end of the active material layer near the tab.

[0075] A mask layer with a preset pattern is disposed on an insulating layer;

[0076] The insulating layer is etched according to a preset pattern to form multiple insulating areas;

[0077] Remove the mask layer.

[0078] When forming multiple insulating regions, an insulating layer is first formed on the first end of the active material layer near the tab. A mask layer is then formed on the insulating layer, and the mask layer includes a preset pattern that can form multiple insulating regions. The insulating layer is etched according to the preset pattern to form multiple insulating regions. After the multiple insulating regions are formed, the mask layer is removed.

[0079] In exemplary embodiments of this application, the insulating layer material includes polyhydroxystyrene, a azidonaphthoquinone ester photoacid-generating agent, an alcohol ether solvent, and additives. Polyhydroxystyrene is a film-forming resin that facilitates the firm coating of the insulating material in the insulating region onto the surface of the active material layer of the current collector. Under the light action (etching) of ultraviolet irradiation, the azidonaphthoquinone ester photoacid-generating agent can generate acidic compounds. These acidic compounds can act as catalysts to cause acidolysis in the irradiated area, resulting in different solubility of the insulating material in the masked area (used to form the insulating region) and the non-masked area in the preset pattern of the mask layer. The alcohol ether solvent, as a solvent, can improve the leveling properties of the insulating material in the insulating region, resulting in a uniform thickness of the formed insulating region. The additive can be a substance that absorbs or controls light, thereby effectively controlling the amount of insulating material in the formed insulating region. The additive can be at least one of ethyl 4-dimethylaminobenzoate and 2-isopropylthioxanthraquinone. When the additive includes ethyl 4-dimethylaminobenzoate, the mass percentage of ethyl 4-dimethylaminobenzoate can be 1-2%. When the additive includes 2-isopropylthioxanthanone, the mass percentage of 2-isopropylthioxanthanone can be 1-2%. Ethyl 4-dimethylaminobenzoate is a high-performance photosensitive material that can improve the photoinitiation efficiency of insulating materials. 2-Isopropylthioxanthanone can be used as a photoinitiator for insulating materials because its long absorption wavelength, close to the wavelength of ultraviolet light emitted, results in excellent photoinitiation efficiency. Appropriate amounts of ethyl 4-dimethylaminobenzoate and 2-isopropylthioxanthanone can promote photoinitiation; the combined use of both yields even better results.

[0080] In an exemplary embodiment of this application, the insulating material in the insulating region possesses both insulating properties and the characteristic of being easily deactivated by ultraviolet light or other light irradiation. This insulating material is coated onto the surface of the active material layer to form an insulating layer. Using a pre-defined pattern in the mask layer, and through etching processes such as ultraviolet irradiation, the insulating material in the insulating layer far from the tab can be removed, leaving only the area corresponding to the tab, thus forming an insulating region. This exposes the active material in the active material layer far from the tab, enabling more effective utilization of the active material. By setting the insulating regions at intervals, i.e., only at the positions corresponding to the tab, the situation where all the active material at the first end of the active material layer is covered by insulating regions and cannot function can be avoided, thereby effectively improving the energy density.

[0081] This application also provides examples 1-4 to more clearly illustrate the insulating material of the insulating region of this application, as shown in Table 1.

[0082] Table 1

[0083]

[0084] In Table 1, the additive in Examples 1-2 is ethyl 4-dimethylaminobenzoate, the additive in Examples 3-4 is 2-isopropylthioxanthrone, and the additives in Examples 5-6 are ethyl 4-dimethylaminobenzoate and 2-isopropylthioxanthrone.

[0085] In an exemplary embodiment of this application, the material of the active material layer is a positive electrode active material.

[0086] In exemplary embodiments of this application, the positive electrode active material includes one of lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, lithium nickel cobalt manganese oxide, and lithium nickel cobalt aluminum oxide.

[0087] In an exemplary embodiment of this application, a method for preparing a positive electrode is provided, such as... Figures 1-4 As shown, the preparation method of the positive electrode includes:

[0088] Step S100: As Figure 2 As shown, a current collector 2 and multiple tabs 3 connected to the current collector 2 are provided.

[0089] Step S200: As Figure 4 As shown, an active material layer 1 is provided on the first side of the current collector 2.

[0090] Step S300: As Figure 4 As shown, multiple insulating regions 4 are provided on the first end 5 of the active material layer 1. The first end 5 is close to multiple tabs 3. The multiple insulating regions 4 are arranged at intervals and correspond one-to-one with the positions of the multiple tabs 3.

[0091] During the manufacturing process of lithium-ion batteries, when the tabs are bent and welded together, the electrode sheets at the tab position tilt downwards. Short circuits may occur between the tabs and at the first end of the active material layer near the tabs due to potential contact. To avoid this problem, multiple insulating areas are set on the first end of the active material layer near the tabs, which can both prevent battery short circuits and improve the safety of the tabs.

[0092] In the exemplary embodiment of this application, the method for preparing the positive electrode sheet involves forming an active material layer on the first side of the current collector and forming multiple insulating regions on the first end of the active material layer near the multiple tabs. The multiple insulating regions are spaced apart and correspond one-to-one with the positions of the multiple tabs, with a portion of the active material layer exposed between adjacent insulating regions. The spaced-apart insulating regions can expose more of the active material in the active material layer, making more efficient use of the active material and avoiding the situation where the presence of too many insulating regions affects the function of the active material, thereby effectively improving the energy density.

[0093] In exemplary embodiments of this application, such as Figure 4As shown, the distance D1 between the two side edges of the insulation region 4 and the corresponding two side edges of the electrode 3 is greater than or equal to a preset distance. To ensure safety when the electrode is bent, the distance D1 between the two side edges of each insulation region and the two side edges of the corresponding electrode needs to be, for example... Figure 4 As shown in the diagram, D1 should be greater than or equal to the preset distance. The preset distance can be set to ensure safety when the tab is bent. Alternatively, the preset distance can be set to ensure safety when the tab is bent while exposing as much of the active material layer between the insulating areas as possible. For example, the preset distance can be 0.5–10 mm, and D1 can be greater than or equal to 0.5–10 mm.

[0094] In the exemplary embodiments of this application, the distance between the two sides of the insulating region and the two sides of the corresponding tab is greater than or equal to a preset distance, so that the length of the insulating region is greater than the length of the connection between the tab and the current collector, ensuring that the tab does not contact the exposed active material layer and is separated by the insulating region. The insulating region with sufficient length can effectively reduce the occurrence of battery short circuits.

[0095] In exemplary embodiments of this application, such as Figure 4 As shown, the width W1 of the first end 5 is greater than or equal to the preset width. To ensure safety when the tab is bent, the distance between the two side edges of each insulation zone and the two side edges of the corresponding tab is considered, for example... Figure 4 As shown in the diagram, D1 should be greater than or equal to a preset distance. Alternatively, the width W1 of each insulation zone can also be greater than or equal to a preset width. The preset width is set to ensure safety when the tab is bent. The preset width can also be set to ensure safety when the tab is bent while exposing as much of the active material layer between the insulation zones as possible.

[0096] When setting the preset width, a preset distance can be considered. While ensuring that the distance between the two side edges of each insulation zone and the two side edges of the corresponding tab is greater than or equal to the preset distance, setting the preset width as N times the preset distance can more effectively ensure safety when the tab is bent. N is a positive integer greater than or equal to 1. For example, the preset width can be 1-5 times the preset distance, meaning the width W1 of each insulation zone can be greater than or equal to 1-5 times the distance D1 between the two side edges of insulation zone 4 and the corresponding two side edges of tab 3.

[0097] In an exemplary embodiment of this application, the width W1 of the first end of the active material layer near the tab is greater than or equal to a preset width, ensuring sufficient width at the first end to prevent short circuits due to potential contact between the tabs or at the first end of the active material layer near the tab during electrode bending. The preset width can be 1-5 times a preset distance, with the specific value determined according to actual needs. Setting the preset width as N times the preset distance more effectively ensures safety during tab bending.

[0098] The width of the first end of the active material layer near the tab can be set to ensure safety when the tab is bent, while also exposing as much of the active material layer as possible. For example, the preset width and preset distance can be equal, i.e., the preset width is twice the preset distance. This can effectively ensure safety when the tab is bent, while also exposing more of the active material in the active material layer. This allows the active material in the active material layer to be used more effectively, reducing the risk of short circuits, and also avoiding the situation where the active material cannot function due to excessive coverage by the insulating coating.

[0099] In an exemplary embodiment of this application, the preparation method further includes:

[0100] An insulating coating is applied to the surface of tab 3.

[0101] Applying an insulating coating to the tab 3 effectively ensures safety during tab bending. The insulating material of the insulating coating on the tab surface and the insulating material of the insulating area can be the same or different. When the insulating material of the insulating coating on the tab surface and the insulating material of the insulating area are the same, they can be completed in the same process, saving processing time.

[0102] In an exemplary embodiment of this application, the insulating material of the insulating region comprises the following components expressed as a percentage by weight:

[0103]

[0104] In an exemplary embodiment of this application, the insulating material of the insulating region comprises the following components expressed as a percentage by weight:

[0105]

[0106] like Figure 5 As shown in the exemplary embodiment of this application, the method for preparing the positive electrode includes setting a plurality of insulating regions 4 at the first end 5 of the active material layer 1, which comprises:

[0107] Step S310: As Figure 3 As shown, an insulating layer is coated on the first end 5 of the active material layer 1.

[0108] Step S320: A mask layer is formed on the insulating layer, the mask layer having a preset pattern;

[0109] Step S330: As Figure 4 As shown, the insulating layer is etched according to a preset pattern to form multiple insulating regions 4;

[0110] Step S340: Remove the mask layer.

[0111] When forming multiple insulating regions, an insulating layer is first formed on the first end of the active material layer near the tab. A mask layer is then formed on the insulating layer, and the mask layer includes a preset pattern that can form multiple insulating regions. The insulating layer is etched according to the preset pattern to form multiple insulating regions. After the multiple insulating regions are formed, the mask layer is removed.

[0112] The etching method can be one of ultraviolet irradiation, X-ray irradiation, electron beam irradiation, or ion beam irradiation.

[0113] In exemplary embodiments of this application, the insulating layer material includes polyhydroxystyrene, azide naphthoquinone ester photoacid generator, alcohol ether solvent, and additives. Etching can be performed using ultraviolet (UV) irradiation. Under UV irradiation, the azide naphthoquinone ester photoacid generator produces acidic compounds. These acidic compounds act as catalysts to induce acidolysis in the irradiated area, resulting in different solubility of the insulating material in the masked area (used to form the insulating area) and non-masked area of ​​the preset pattern in the mask layer, thereby forming different insulating areas.

[0114] In an exemplary embodiment of this application, the insulating material in the insulating region possesses both insulating properties and the characteristic of being easily deactivated by ultraviolet light or other light irradiation. This insulating material is coated onto the surface of the active material layer to form an insulating layer. Using a pre-defined pattern in the mask layer, and through etching methods such as ultraviolet irradiation, the insulating material in the insulating layer far from the tab can be removed, leaving only the area corresponding to the tab, thus forming an insulating region. This exposes the active material in the active material layer far from the tab, enabling more effective utilization of the active material. By setting the insulating regions at intervals, i.e., only at the positions corresponding to the tab, the situation where all the active material at the first end of the active material layer is covered by insulating regions and cannot function can be avoided, thereby effectively improving the energy density.

[0115] In an exemplary embodiment of this application, the material of the active material layer is a positive electrode active material.

[0116] In exemplary embodiments of this application, the positive electrode active material includes one of lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, lithium nickel cobalt manganese oxide, and lithium nickel cobalt aluminum oxide.

[0117] In an exemplary embodiment of this application, the current collector has a sheet-like structure. An active material layer is disposed on a first side of the current collector, and multiple insulating regions are disposed on the active material layer. The multiple insulating regions are disposed on a first end of the active material layer, and the first end is close to multiple electrodes. The multiple insulating regions are spaced apart and correspond one-to-one with the positions of the multiple electrodes. Alternatively, an active material layer may also be disposed on a second side of the current collector, and multiple insulating regions may be disposed on the active material layer.

[0118] That is, a first active material layer is disposed on the first side of the current collector, in Figure 3 In the diagram, the surface shown by the current collector in figure number 2 is the first side surface. Figure 4 The first active material layer is designated as number 1. Multiple first insulating regions are formed on the first end of the first active material layer near the electrode tab. Figure 4 Reference numeral 4 represents multiple first insulating regions, which are disposed on the first end of the active material layer, close to multiple electrodes. These first insulating regions are spaced apart and correspond one-to-one with the positions of the electrodes. On the second side of the current collector, which is the side opposite to the first side, in... Figure 3 In the diagram, the current collector shown by reference numeral 2 is the first side surface, and the side surface opposite to the first side surface is the second side surface. A second active material layer is disposed on the second side surface. A plurality of second insulating regions are disposed at the first end of the second active material layer near the electrode tab. The plurality of first insulating regions correspond one-to-one with the plurality of second insulating regions, and the plurality of second insulating regions are spaced apart and correspond one-to-one with the positions of the plurality of electrodes tabs.

[0119] By setting a first active material layer and a second active material layer on the first and second sides of the current collector, the area ratio of active material in the battery can be increased, thereby improving energy density. At the same time, multiple first insulating regions are set at intervals on the first end of the first active material layer, and multiple second insulating regions are set at intervals on the first end of the second active material layer. The multiple first insulating regions correspond one-to-one with the multiple second insulating regions, and each of them corresponds one-to-one with the position of multiple tabs. This can not only avoid battery short circuits and improve the safety of the tabs, but also further improve energy density.

[0120] In exemplary embodiments of this application, the positive electrode sheet is used to prepare a wound lithium battery cell or a stacked lithium battery cell.

[0121] The exemplary embodiments of this application also provide a lithium-ion battery, including a negative electrode, a separator, and a positive electrode provided in the exemplary embodiments of this application. The exemplary embodiments of this application also provide a lithium-ion battery that not only effectively reduces the risk of battery short circuits but also improves the battery's energy density.

[0122] In the description of this application, it should be noted that the terms "upper," "lower," "left," "right," etc., indicating orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application 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, and therefore should not be construed as a limitation of this application. It is understood that the terms "first," "second," etc., used in this application can be used to describe various structures, but these structures are not limited by these terms. These terms are only used to distinguish one structure from another.

[0123] In this application, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0124] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A positive electrode plate, characterized in that, The positive electrode includes: A current collector and multiple tabs connected to the current collector; An active material layer is disposed on the first side of the current collector; Multiple insulating regions are disposed on a first end of the active material layer, the first end being close to the multiple electrodes; the multiple insulating regions are spaced apart and correspond one-to-one with the positions of the multiple electrodes; The insulating material of the insulating region comprises the following components, expressed as a percentage by weight: Polyhydroxystyrene 11-15%; Azide naphthoquinone ester photoacid-producing agents: 3-6%; Alcohol ether solvent 75-85%; Additives 1-3%; The sum of the weight percentages of all the above components is 100%; The insulating material in the insulating region has the characteristics of insulation and light-induced deactivation; The width of each insulating region is greater than or equal to 1-5 times the distance between the two side edges of the insulating region and the corresponding two side edges of the tab.

2. The positive electrode sheet according to claim 1, characterized in that, The distance between the two sides of the insulating area and the two sides of the corresponding electrode tab is greater than or equal to a preset distance.

3. The positive electrode sheet according to claim 2, characterized in that, The width of the first end is greater than or equal to the preset width.

4. The positive electrode sheet according to any one of claims 1-3, characterized in that, The positive electrode also includes an insulating coating applied to the surfaces of the plurality of tabs.

5. The positive electrode sheet according to claim 4, characterized in that, The insulating material of the plurality of insulating regions is the same as the insulating material of the insulating coating on the surface of the tab.

6. The positive electrode sheet according to claim 1, characterized in that, The insulating material of the insulating region comprises the following components, expressed as a percentage by weight: Polyhydroxystyrene 12-14%; Azide naphthoquinone ester photoacid-producing agent 3.5-5.5%; Alcohol ether solvent 78-82%; Additives 1.5-2.5%.

7. The positive electrode sheet according to claim 1, characterized in that, The additive is selected from at least one of ethyl 4-dimethylaminobenzoate and 2-isopropylthioxanthrone.

8. The positive electrode sheet according to claim 7, characterized in that, When the additive includes ethyl 4-dimethylaminobenzoate, the mass percentage of ethyl 4-dimethylaminobenzoate is 1 to 2%.

9. The positive electrode sheet according to claim 7, characterized in that, When the additive includes the 2-isopropylthioxanthraquinone, the mass percentage of the 2-isopropylthioxanthraquinone is 1 to 2%.

10. The positive electrode sheet according to claim 1, characterized in that, The active material layer is a positive electrode active material, which includes one of lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, lithium nickel cobalt manganese oxide, and lithium nickel cobalt aluminum oxide.

11. A method for preparing a positive electrode sheet, characterized in that, Includes the following steps: Provides a current collector and multiple tabs connected to the current collector; An active material layer is disposed on the first side of the current collector; Multiple insulating regions are provided on the first end of the active material layer, the first end is close to multiple electrodes, the multiple insulating regions are spaced apart, and their positions correspond one-to-one with the positions of the multiple electrodes; The insulating material of the insulating region comprises the following components, expressed as a percentage by weight: Polyhydroxystyrene 11-15%; Azide naphthoquinone ester photoacid-producing agents: 3-6%; Alcohol ether solvent 75-85%; Additives 1-3%; The sum of the weight percentages of all the above components is 100%; The insulating material in the insulating region has the characteristics of insulation and light-induced deactivation; The width of each insulating region is greater than or equal to 1-5 times the distance between the two side edges of the insulating region and the corresponding two side edges of the tab.

12. The method for preparing the positive electrode sheet according to claim 11, characterized in that, The distance between the two sides of the insulating area and the two sides of the corresponding electrode tab is greater than or equal to a preset distance.

13. The method for preparing the positive electrode sheet according to claim 11, characterized in that, The width of the first end is greater than or equal to the preset width.

14. The method for preparing the positive electrode sheet according to any one of claims 11-13, characterized in that, The preparation method further includes: An insulating coating is applied to the surfaces of the plurality of tabs.

15. The method for preparing the positive electrode sheet according to claim 14, characterized in that, The insulating material of the plurality of insulating regions is the same as the insulating material of the insulating coating on the surface of the tab.

16. The method for preparing the positive electrode sheet according to claim 11, characterized in that, The insulating material of the insulating region comprises the following components, expressed as a percentage by weight: Polyhydroxystyrene 12-14%; Azide naphthoquinone ester photoacid-producing agent 3.5-5.5%; Alcohol ether solvent 78-82%; Additives 1.5-2.5%.

17. The method for preparing the positive electrode sheet according to claim 11, characterized in that, The additive is selected from at least one of ethyl 4-dimethylaminobenzoate and 2-isopropylthioxanthrone.

18. The method for preparing the positive electrode sheet according to claim 17, characterized in that, When the additive includes ethyl 4-dimethylaminobenzoate, the mass percentage of ethyl 4-dimethylaminobenzoate is 1 to 2%.

19. The method for preparing the positive electrode sheet according to claim 17, characterized in that, When the additive includes the 2-isopropylthioxanthraquinone, the mass percentage of the 2-isopropylthioxanthraquinone is 1 to 2%.

20. The method for preparing the positive electrode sheet according to claim 11, characterized in that, The active material layer is a positive electrode active material, which includes one of lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, lithium nickel cobalt manganese oxide, and lithium nickel cobalt aluminum oxide.

21. The method for preparing the positive electrode sheet according to claim 11, characterized in that, The provision of multiple insulating regions at the first end of the active material layer includes: An insulating layer is coated on the first end of the active material layer near the tab. A mask layer is disposed on the insulating layer, and the mask layer has a preset pattern; The insulating layer is etched according to the preset pattern to form a plurality of insulating regions; Remove the mask layer.

22. A lithium-ion battery, characterized in that, It includes a negative electrode, a separator, and a positive electrode as described in any one of claims 1-10.

Images