Electrode plate and preparation method thereof, battery, battery pack and power utilization device

Abstract

The invention provides an electrode plate, a preparation method of the electrode plate, a battery, a battery pack and a power utilization device. The current collector is connected with the tab, and an active material layer is arranged on the surface of at least one side of the current collector; the supporting layer is arranged on the surface of one side, far away from the tab, of the active material layer and covers part of the active material layer. The battery with the electrode plate has high safety performance and structural stability, internal short circuit and shell corrosion are not easy to occur, and capacity loss is reduced. Moreover, the method for preparing the electrode plate is simple and convenient to operate and suitable for large-scale production.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to electrode sheets and their preparation methods, batteries, battery packs, and electrical devices. Background Technology

[0002] With the widespread application of lithium batteries in consumer electronics, new energy vehicles, and large-scale energy storage systems, battery safety is always the top priority. Ceramic coating on the positive electrode is a crucial safety design strategy for lithium batteries, significantly reducing the risk of short circuits and thermal runaway through a triple effect of mechanical reinforcement, electrochemical optimization, and thermal protection. However, in current industry designs, the ceramic coating on the positive electrode only applies to the ceramic edge on one side of the electrode tab, while the opposite side and the negative electrode are not coated. In aluminum-cased batteries, the opposite side of the tab usually corresponds to the bottom of the core, which faces greater safety risks. For example, conductive foreign matter introduced during manufacturing processes, such as electrode powder shedding, often accumulates at the bottom of the battery, causing internal short circuits, aluminum shell corrosion (conductive foreign matter connects to the negative electrode and aluminum shell), and in severe cases, even thermal runaway. Summary of the Invention

[0003] This application aims to at least partially address one of the technical problems in related technologies. To this end, one objective of this application is to provide an electrode sheet and its preparation method, a battery, a battery pack, and an electrical device. The battery having this electrode sheet exhibits high safety performance and structural stability, is less prone to internal short circuits and casing corrosion, and reduces capacity loss. Furthermore, the method for preparing this electrode sheet is simple to operate and suitable for mass production.

[0004] The first aspect of this application discloses an electrode sheet comprising: a tab; a current collector connected to the tab, wherein at least one surface of the current collector is provided with an active material layer; and a support layer disposed on the surface of the active material layer away from the tab and covering a portion of the active material layer.

[0005] The electrode sheet of this application has a support layer on the surface of the active material layer away from the tab, which effectively enhances the structural support at the bottom of the battery core, improves structural stability, avoids safety risks caused by direct load-bearing with soft current collectors (such as copper foil), reduces internal short circuits and aluminum shell corrosion caused by conductive foreign objects, reduces the extent of separator thermal shrinkage, and also reduces internal short circuits caused by contact between the positive and negative electrode sheets due to separator thermal shrinkage. Furthermore, the support layer partially covers the active material layer, reducing the overlap area between the support layer and the active material, reducing capacity loss, and improving the battery's protection against bottom conductive foreign objects, shell corrosion, and separator thermal shrinkage, thereby significantly improving the overall safety of the battery.

[0006] According to embodiments of this application, the electrode sheet may also have the following additional technical features: According to an embodiment of this application, the width of the support layer is 2 mm to 5 mm; And / or, the thickness of the support layer is 10 μm to 30 μm; And / or, the material of the support layer includes SiO2, alumina, boehmite, and boron nitride.

[0007] According to an embodiment of this application, the electrode sheet further comprises: An insulating layer is disposed between the tab and the active material layer, and does not cover or covers part of the active material layer.

[0008] According to an embodiment of this application, the width of the insulating layer is 2 mm to 30 mm; And / or, the thickness of the insulating layer is 10 μm to 80 μm; And / or, the width of the overlap area between the insulating layer and the active material layer is 0 mm to 30 mm; And / or, the material of the insulating layer includes SiO2, alumina, boehmite, and boron nitride.

[0009] According to an embodiment of this application, the width of the insulating layer is 2 mm to 5 mm; And / or, the width of the overlap area between the insulating layer and the active material layer is 10 mm to 30 mm; And / or, the width of the overlap area between the insulating layer and the active material layer is 0 mm to 2 mm.

[0010] According to an embodiment of this application, the electrode sheet is selected from the negative electrode sheet, and the material of the current collector includes copper, copper alloy, nickel, or nickel alloy.

[0011] According to an embodiment of this application, the electrode sheet is selected from the positive electrode sheet, and the material of the current collector includes aluminum, aluminum alloy, nickel, or nickel alloy.

[0012] A second aspect of this application discloses a method for preparing the electrode sheet described in the first aspect, the method comprising: An active material layer is formed on at least one side surface of the current collector, and a tab setting area is pre-set on one side edge of the current collector; A support layer is formed on the side surface of the active material layer away from the tab setting area, covering a portion of the active material layer; A tab is disposed within the tab setting area to obtain the electrode sheet.

[0013] Therefore, this preparation method is simple to operate and suitable for large-scale production.

[0014] According to an embodiment of this application, the method includes: An active material layer is formed on at least one side surface of the current collector, and a tab setting area is pre-set on one side edge of the current collector; On the surface of the active material layer, along the length direction of the current collector, the slurry of the support layer is applied and cured to form at least one support area. The support area does not coincide with the edge of the active material layer along the length direction of the current collector. A pre-set dividing line is provided within the support area. The dividing line extends along the length direction of the current collector and does not coincide with the edge of the support area. The current collector, active material layer, and support region are cut along the dividing line; A tab is disposed within the tab setting area to obtain at least two electrode plates.

[0015] According to an embodiment of this application, the method includes: An active material layer is formed on at least one side surface of the current collector, and a tab setting area is pre-set on one side edge of the current collector; On the surface of the active material layer away from the tab placement area, a slurry of a support layer is applied to cover part of the active material layer and cured to form a support layer. A tab is disposed within the tab setting area to obtain the electrode sheet.

[0016] According to an embodiment of this application, a slurry for applying the insulating layer is coated between the active material layer and the tab setting area and cured to obtain the insulating layer, wherein the insulating layer may or may not cover a portion of the active material layer.

[0017] A third aspect of this application discloses a battery comprising: the electrode sheet described in the first aspect or an electrode sheet obtained using the method for preparing the electrode sheet described in the second aspect. The battery of this application exhibits high safety performance and structural stability.

[0018] This application discloses a battery pack in its fourth aspect, comprising: the electrode sheet described in the first aspect, an electrode sheet obtained by the method for preparing the electrode sheet described in the second aspect, and at least two batteries described in the third aspect. The battery pack of this application has high safety performance and structural stability.

[0019] The fifth aspect of this application discloses an electrical device comprising: the electrode sheet described in the first aspect, an electrode sheet obtained using the method for preparing the electrode sheet described in the second aspect, the battery described in the third aspect, and the battery pack described in the fourth aspect. Therefore, the electrical device of this application offers high safety in use.

[0020] Additional aspects and advantages of this application 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 this application. Attached Figure Description

[0021] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 A schematic diagram of an electrode sheet structure according to an embodiment of this application is shown; Figure 2 This invention illustrates a process flow diagram for preparing an electrode sheet according to one embodiment of the present application; Figure 3 This illustration shows a schematic diagram of the electrode sheet coating effect according to an embodiment of this application; Figure 4 This illustration shows a schematic diagram of a dual-coating electrode sheet according to an embodiment of this application; Figure 5 A schematic diagram of an electrode sheet structure according to another embodiment of this application is shown.

[0022] Figure label: 1: Electrode sheet; 100: Tab; 200: Current collector; 300: Active material layer; 400: Support layer; 500: Insulating layer; A: Dividing line; 10: Support area. Detailed Implementation

[0023] The embodiments of this application are described in detail below. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0024] It should be noted that 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. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Furthermore, in the description of this application, unless otherwise stated, "multiple" means two or more.

[0025] The endpoints and any values ​​of the ranges disclosed in this application are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this application.

[0026] In this application, the terms "comprising" or "including" are open-ended expressions, meaning they include the content specified in this application but do not exclude other aspects.

[0027] Ceramic coating on the positive electrode is a crucial safety design strategy for lithium batteries. Through mechanical reinforcement, electrochemical optimization, and thermal protection, it significantly reduces the risk of short circuits and thermal runaway. However, in current industry designs, the ceramic coating on the positive electrode only covers the side of the electrode tab, while the opposite side and the negative electrode are not coated. In aluminum-cased batteries, the opposite side of the tab usually corresponds to the bottom of the core, which faces greater safety risks. For example, conductive foreign matter introduced during manufacturing, such as electrode powder shedding, often accumulates at the bottom of the battery, causing internal short circuits, aluminum shell corrosion (conductive foreign matter connects with the negative electrode and aluminum shell), and in severe cases, even thermal runaway.

[0028] In existing technologies, ceramic material is coated onto the surface of the metal current collector surrounding the active material layer to form an insulating edge. This method applies to one side of the electrode tab; however, on the other side of the tab, usually at the bottom of the core, this part of the electrode needs to provide support. This design results in the bottom ceramic-coated metal substrate providing support (usually the bottom negative electrode, whose metal substrate is very soft copper foil), posing a significant safety hazard. Furthermore, the manufacturing process is cumbersome and results in a large waste of metal substrate.

[0029] Therefore, the first aspect of this application proposes an electrode sheet. According to an embodiment of this application, see... Figure 1 The electrode sheet 1 includes: a tab 100; a current collector 200 connected to the tab, wherein at least one side surface of the current collector is provided with an active material layer 300; and a support layer 400 disposed on the side surface of the active material layer 300 away from the tab 100 and covering a portion of the active material layer 300.

[0030] The electrode sheet of this application has a support layer on the surface of the active material layer away from the tab, which effectively enhances the structural support at the bottom of the battery core, improves structural stability, avoids safety risks caused by direct load-bearing with soft current collectors (such as copper foil), reduces internal short circuits and aluminum shell corrosion caused by conductive foreign objects, reduces the extent of separator thermal shrinkage, and also reduces internal short circuits caused by contact between the positive and negative electrode sheets due to separator thermal shrinkage. Furthermore, the support layer partially covers the active material layer, reducing the overlap area between the support layer and the active material, reducing capacity loss, and improving the battery's protection against bottom conductive foreign objects, shell corrosion, and separator thermal shrinkage, thereby significantly improving the overall safety of the battery. For example, Figure 1 The negative electrode plate is yellow, and the copper foil tabs are yellow. Figure 5 The white part is the positive electrode sheet, and the white part is the aluminum foil tab.

[0031] According to embodiments of this application, the width of the support layer is 2 mm to 5 mm, for example, 2 mm, 3 mm, 4 mm, or 5 mm. This effectively covers the active material area at the bottom of the electrode (the side furthest from the tab), providing sufficient insulation and support area, while avoiding excessive intrusion into the active area that could lead to significant capacity loss. This suitable width ensures structural strength, improves battery safety, and also takes into account electrochemical performance. According to embodiments of this application, the thickness of the support layer is 10 μm to 30 μm. In some embodiments, the thickness of the support layer is 10 μm, 15 μm, 20 μm, 25 μm, or 30 μm. This provides good support and insulation, preventing thermal runaway, avoiding powder shedding or detachment due to excessive thickness, and preventing insufficient support and insulation due to excessive thinness, which could lead to puncture by foreign objects.

[0032] According to embodiments of this application, the material of the support layer includes SiO2, alumina, and boehmite.

[0033] According to an embodiment of this application, the electrode sheet 1 further includes an insulating layer 500, which is disposed between the tab 100 and the active material layer 300, and does not cover or only partially covers the active material layer 300. This effectively blocks direct electrical contact and short-circuit risks between the tab and the active material layer, improves the electrical insulation reliability of the tab area, enhances battery safety under extreme operating conditions, and prevents failures caused by abnormal heating or electrochemical corrosion at the tab.

[0034] According to embodiments of this application, the width of the insulating layer is 2 mm to 30 mm, for example 2 mm, 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, or 30 mm, and exemplaryly 2 μm to 5 μm. Therefore, while effectively isolating the tabs from the active material layer and preventing short-circuit risks, it reduces the area occupied by the active material layer, thereby minimizing the negative impact on battery energy density while ensuring battery safety.

[0035] According to embodiments of this application, the thickness of the insulating layer is 10 μm to 80 μm, for example, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, or 80 μm, with 10 μm to 30 μm being an exemplary value. This achieves good insulation while preventing the insulating layer from detaching and shedding powder due to excessive thickness.

[0036] According to embodiments of this application, the overlap width between the insulating layer and the active material layer is 0 mm to 30 mm, for example, 0 mm, 0.2 mm, 0.5 mm, 0.8 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, or 30 mm, exemplarily 0 mm to 2 mm. This effectively isolates the tabs from the active material layer, preventing short-circuit risks, while also reducing battery capacity loss.

[0037] According to embodiments of this application, the insulating layer is made of SiO2, alumina, boehmite, or boron nitride.

[0038] According to an embodiment of this application, the electrode sheet is selected from the negative electrode sheet, and the material of the current collector includes copper, copper alloy, nickel, or nickel alloy.

[0039] According to an embodiment of this application, the electrode sheet is selected from the positive electrode sheet, and the material of the current collector includes aluminum, aluminum alloy, nickel, or nickel alloy.

[0040] For example, when the positive electrode sheet is used in a lithium-ion battery, the positive electrode active material can be any positive electrode active material known in the art for lithium-ion batteries. As an example, the positive electrode active material may include at least one of the following materials: lithium phosphates with an olivine structure, lithium transition metal oxides, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium transition metal oxides include, but are not limited to, lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, and lithium nickel cobalt manganese oxides (such as LiNiO2). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co0.1 Mn 0.1 O2 (which can also be abbreviated as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.8 Co 0.15 Al 0.05 O2), or at least one of its modified compounds, etc. Examples of the lithium phosphate with olivine structure may include but are not limited to lithium iron phosphate (such as LiFePO4 (which can also be abbreviated as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate or a composite material of lithium manganese iron phosphate and carbon.

[0041] Exemplarily, when the positive electrode sheet is used in a sodium ion battery, the positive electrode active material may include at least one of the following materials: Na x MO2, where M includes at least one of Ti, V, Mn, Co, Ni, Fe, Zn, V, Zr, Ce, Cr, Cu, and 0 < x ≤ 1.

[0042] Polyanionic compounds: NaFePO4, Na3V2(PO4)3 (sodium vanadium phosphate, abbreviated as NVP), Na4Fe3(PO4)2(P2O7), NaM’PO4F (M’ includes at least one of V, Fe, Mn, and Ni), and Na3(VO y )2(PO4)2F 3-2y (where 0 ≤ y ≤ 1).

[0043] [[ID=:List]]Prussian blue compounds: Na a Me b Me’ c (CN)6, where Me and Me’ each independently include at least one of Ni, Cu, Fe, Mn, Co, Zn, 0 < a ≤ 2, 0 < b < 1, 0 < c < 1. [[ID=:List]]

[0044] In some embodiments, the positive electrode active material includes at least one of Na X1 M1O2, Na X2 M2[M3(CN)6], NaFePO4, Na3V2(PO4)3, Na2M4P2O7, Na2Fe2(SO4)3, Na2M4(SO4)2·2H2O, where 0 < x1 ≤ 1, M1 includes at least one of Ni, Co, Mn, Fe, and Cu, 0 < x2 < 6, M2 includes at least one of Ni, Fe, and Mn, M3 includes at least one of Fe and Mn, and M4 includes at least one of Fe, Co, Mn, and Cu.

[0045] In some embodiments, the positive electrode active material comprises a ternary layered sodium-based material; exemplarily, a sodium-ion battery comprises NaNi. 1 / 3 Fe 1 / 3 Mn 1 / 3 O2, NaNi 1 / 3 Mn 1 / 3 Co 1 / 3 O2(NMC), Na3V2(PO4)3(NMN), Na 0.9 Mn 0.6 Fe 0.4 One of PO4 (NMFP), sodium iron pyrophosphate Na4Fe3(PO4)2(P2O7), and sodium ferrocyanide.

[0046] According to embodiments of this application, the positive electrode active material layer may optionally include a positive electrode conductive agent. As an example, the positive electrode conductive agent may include at least one selected from superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0047] According to embodiments of this application, the positive electrode active material layer may optionally include a positive electrode binder. As an example, the positive electrode binder may include at least one selected from polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0048] According to embodiments of this application, the negative electrode active material may be a negative electrode active material known in the art for use in batteries. As an example, the negative electrode active material may include at least one of the following materials: graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, etc. Silicon-based materials may include at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may include at least one of elemental tin, tin oxide compounds, and tin alloys.

[0049] According to embodiments of this application, the negative electrode active material layer may optionally include a negative electrode binder. The negative electrode binder may include at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0050] According to embodiments of this application, the negative electrode active material layer may optionally include a negative electrode conductive agent. The negative electrode conductive agent may include at least one selected from superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0051] According to embodiments of this application, the negative electrode active material layer may optionally include other additives, such as thickeners (e.g., sodium carboxymethyl cellulose (CMC-Na)).

[0052] A second aspect of this application discloses a method for preparing the electrode sheet described in the first aspect. According to embodiments of this application, see [link to embodiment]. Figure 2 The method includes: S100 forms an active material layer In this step, an active material layer is formed on at least one side surface of the current collector, and a tab setting area is pre-set on one side edge of the current collector.

[0053] S200 forms a support layer In this step, a support layer is formed on the side surface of the active material layer away from the tab setting area, covering a portion of the active material layer.

[0054] According to an embodiment of this application, on the surface of the active material layer away from the tab setting area, a slurry of a support layer is applied to cover part of the active material layer and cured to form a support layer.

[0055] According to an embodiment of this application, step S200 further includes: applying and curing a slurry of the support layer on the surface of the active material layer along the length direction of the current collector to form at least one support area, wherein the support area does not coincide with the edge of the active material layer along the length direction of the current collector; a pre-set dividing line is provided within the support area, wherein the dividing line extends along the length direction of the current collector and does not coincide with the edge of the support area.

[0056] See Figure 3 First, an active material layer 300 is formed on at least one side surface of the current collector 200, and a tab setting area is pre-set on one side edge of the current collector 200. Next, a support layer slurry is coated and cured on the surface of the active material layer 300 along the length direction of the current collector 200 to form at least one support region 10. This support region 10 does not coincide with the edge of the active material layer 300 along the length direction of the current collector 200. A dividing line A is pre-set within the support region 10, extending along the length direction of the current collector 200 and not coinciding with the edge of the support region 10. Then, the current collector 200, the active material layer 300, and the support region 10 are cut along the dividing line A, and then tabs are set, thus obtaining two electrode sheets at once. See also... Figure 4 Two spaced active material layers are formed on the current collector, and a support region is then coated on each active material layer. By cutting the support region and the current collector between the two active material layers, four electrode sheets can be obtained at once. Therefore, the method of this application can obtain multiple electrode sheets at once, which is simple to operate, greatly improves the preparation efficiency, and reduces the preparation cost.

[0057] According to an embodiment of this application, see Figure 3 The slurry of the insulating layer 500 is applied between the active material layer 300 and the tab 100 setting area and cured to obtain the insulating layer 500, which may or may not cover part of the active material layer 300.

[0058] S300 Setting of Electrodes In this step, a tab is set in the tab setting area to obtain the electrode sheet.

[0059] It is understandable that the methods of setting the electrode tabs mainly include welding connection (such as ultrasonic welding, laser welding) and integral forming (such as extending the current collector area to form the electrode tab by stamping, cutting, etc.). The specific method can be flexibly selected according to the electrode material, process requirements and equipment conditions.

[0060] It should be noted that the features and advantages described above for the electrode sheet also apply to the method for preparing the electrode sheet, and will not be repeated here.

[0061] A third aspect of this application discloses a battery comprising: the electrode sheet described in the first aspect or an electrode sheet obtained using the method for preparing the electrode sheet described in the second aspect. The battery of this application exhibits high safety performance and structural stability.

[0062] According to embodiments of this application, the battery includes a positive electrode, a negative electrode, an electrolyte, and a separator. During battery charging and discharging, active ions repeatedly insert and extract between the positive and negative electrodes. The electrolyte acts as a conductor of ions between the positive and negative electrodes. The separator is disposed between the positive and negative electrodes, primarily to prevent short circuits between the positive and negative electrodes, while simultaneously allowing ions to pass through.

[0063] According to the embodiments of this application, the positive electrode of the battery can be selected from the electrode sheet described in the first aspect, or it can be a different electrode sheet from the first aspect, in order to reduce capacity loss. The specific selection can be made flexibly according to the actual situation.

[0064] This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected. According to embodiments of this application, the separator membrane material may include at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, or polyvinylidene fluoride.

[0065] This application does not impose any particular limitation on the type of electrolyte, which may include electrolyte salts and solvents. Exemplarily, electrolyte salts include lithium hexafluorophosphate / sodium (Li / NaPF6), lithium hexafluoroantimonyate / sodium (LiAsF6), lithium perchlorate / sodium (LiClO4), lithium tetrafluoroborate / sodium (LiBF4), lithium hexafluoroacetylacetonate / sodium (LiDFH), lithium bis(oxalate-borate) / sodium (LiBOB), lithium bis(trifluoromethanesulfonylimide) / sodium (LiTFSI), lithium di(fluorooxalate-borate) / sodium (LiDFOB), and lithium bis(trifluoromethanesulfonylimide) / sodium (LiTFSI). At least one of lithium / sodium fluorosulfonylimide (LiFSI); the organic solvent includes at least one of ethylene carbonate (EC), dimethyl carbonate (DMC), diethyl carbonate (DEC), acetonitrile (ACN), fluoroethylene carbonate (FEC), vinylene carbonate (VC), dimethyl sulfoxide (DMSO), dimethylformamide (DMF), ethyl methyl carbonate (EMC), propylene carbonate (PC), methylpyrrolidone (NMP), tetrahydrofuran (THF), and 1,2-dimethoxyethane (DME).

[0066] According to embodiments of this application, the battery may include an outer packaging. This outer packaging is used to encapsulate the positive electrode, the negative electrode, and the electrolyte.

[0067] According to embodiments of this application, the outer packaging may include a shell and a cover. The shell may include a bottom plate and side plates connected to the bottom plate, the bottom plate and side plates forming a receiving cavity. The shell has an opening communicating with the receiving cavity, and the cover can be placed over the opening to close the receiving cavity.

[0068] According to embodiments of this application, the outer packaging of the battery can be a hard shell, such as a hard plastic shell, an aluminum shell, or a steel shell.

[0069] The outer packaging of batteries can also be a soft pack, such as a pouch. The material of the soft pack can be aluminum-plastic film, etc.

[0070] The battery of this application may be in the form of a single battery cell or a battery module. A single battery cell includes a casing, an electrode core, and an electrolyte. The casing forms an accommodating space, and the electrode core and electrolyte are disposed within the accommodating space. The electrode core may include a positive electrode, a negative electrode, and a separator, which are arranged in a stacked or wound manner. In some embodiments, the single battery cells can be assembled into a battery module. The number of single battery cells contained in a battery module can be one or more, and the specific number can be selected by those skilled in the art based on the application and capacity of the battery module.

[0071] This application discloses a battery pack in a fourth aspect, comprising: the electrode sheet described in the first aspect, an electrode sheet obtained using the method for preparing the electrode sheet described in the second aspect, and at least two batteries described in the third aspect. The battery pack of this application has high safety performance and structural stability. In some embodiments, the battery pack may contain one or more batteries, the specific number of which can be selected by those skilled in the art based on the application and capacity of the battery pack.

[0072] The fifth aspect of this application discloses an electrical device comprising: the electrode sheet described in the first aspect, an electrode sheet obtained using the method for preparing the electrode sheet described in the second aspect, the battery described in the third aspect, and the battery pack described in the fourth aspect. Therefore, the electrical device of this application offers high safety in use.

[0073] Battery cells, battery modules, and battery packs can be used as power sources for electrical devices or as energy storage units for electrical devices. Electrical devices can include, but are not limited to, mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships, energy storage systems, etc.

[0074] As an electrical device, you can choose individual battery cells, battery modules, or battery packs according to your usage requirements.

[0075] As one example, the electrical device can be a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, etc. To meet the high power and high energy density requirements of the battery for this electrical device, a battery pack or battery module can be used.

[0076] Another example of the device could be a mobile phone, tablet computer, laptop computer, etc. This device typically requires a slim and lightweight design and can use a single battery cell as its power source.

[0077] It should be noted that the features and advantages described above for the electrode sheet of the first aspect of this application also apply to the battery of the third aspect, the battery pack of the fourth aspect, and the power supply device of the fifth aspect, and will not be repeated here.

[0078] The following will explain the solution of this application with reference to embodiments. Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be considered as limiting the scope of this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0079] Example 1 In this embodiment, a lithium-ion battery is prepared according to the following method: 1. Preparation of positive electrode sheet See Figure 3 A positive electrode active slurry (lithium iron phosphate) is coated on both sides of the positive electrode foil (aluminum foil) and dried to form a positive electrode active material layer. A boehmite ceramic slurry is coated on the side of the positive electrode active layer closest to the pre-set tab region, and a strip of ceramic slurry is coated in the middle of the positive electrode active layer. This is dried to form an insulating layer on the side of the positive electrode active layer closest to the pre-set tab region and a support region in the middle of the positive electrode active layer. The foil is then rolled, slit, and die-cut, with the slit line positioned at the center of the support region, to obtain... Figure 1 The positive electrode shown.

[0080] The width of the active material layer in the positive electrode sheet is 100 mm, and the surface density on one side is 175 g / m³. 2 The support layer has a width of 1 mm and a thickness of 20 μm, the insulating layer has a width of 2.5 mm and a thickness of 20 μm, and the overlap between the insulating layer and the positive electrode active material layer is 1 mm.

[0081] 2. Preparation of negative electrode sheet See Figure 3 A negative electrode active slurry (graphite) is coated on both sides of the negative electrode foil (copper foil) and dried to form a negative electrode active material layer. A boehmite ceramic slurry is coated on the side of the negative electrode active layer closest to the pre-set tab area, and a strip of ceramic slurry is coated in the middle of the negative electrode active layer. This is dried to form an insulating layer on the side of the negative electrode active layer closest to the pre-set tab area, and a support area in the middle of the negative electrode active layer. The foil is then rolled, slit, and die-cut, with the slit line positioned at the center of the support area, resulting in... Figure 1 The negative electrode shown.

[0082] The width of the active material layer in the negative electrode sheet is 104.5 mm, and the surface density on one side is 100 g / m³. 2 The support layer has a width of 2 mm and a thickness of 10 μm, the insulating layer has a width of 3 mm and a thickness of 20 μm, and the overlap between the insulating layer and the negative electrode active material layer is 2 mm.

[0083] 3. Diaphragm Polyethylene (PE), 108mm wide 4. Electrolyte The ingredients are 50% ethylene carbonate (EC), 30% propylene carbonate (PC), 10% lithium hexafluorophosphate (LiPF6), and 10% vinylene carbonate (VC).

[0084] 5. Assembly After the electrode sheets are cut, they are wound together with the diaphragm to form a core. The core is then welded to the cover plate, then installed in an aluminum shell, and finally electrolyte is injected into the injection hole.

[0085] Examples 2-9 The lithium-ion battery was prepared according to the method of Example 1, except that the dimensions of the support layer, active material layer and insulating layer of the negative electrode sheet are shown in Table 1.

[0086] Table 1 Negative Electrode

[0087] Example 10 The lithium-ion battery was prepared according to the method of Example 1, except that step 1 is as follows: 1. Preparation of positive electrode sheet A positive electrode active slurry (lithium iron phosphate) is coated on both sides of the positive electrode foil (aluminum foil) and dried to form a positive electrode active material layer. A boehmite ceramic slurry is coated on the side of the positive electrode active layer near the pre-set area of ​​the tab and dried to form an insulating layer. The foil is then rolled and die-cut to obtain the positive electrode sheet.

[0088] The width of the active material layer in the positive electrode sheet is 100 mm, and the surface density on one side is 175 g / m³. 2 The insulating layer has a width of 2.5 mm and a thickness of 20 μm, and the overlap between the insulating layer and the positive electrode active material layer is 1 mm.

[0089] Examples 11-18 The lithium-ion battery was prepared according to the method of Example 10, except that the dimensions of the support layer, active material layer and insulating layer of the negative electrode sheet are shown in Table 2.

[0090] Table 2 Negative Electrode Sheets

[0091] Comparative Example 1 The lithium-ion battery was prepared according to the method in Example 1, except that the method for preparing the negative electrode sheet is as follows: A negative electrode active slurry (graphite) is coated on both sides of the negative electrode foil (copper foil) and dried to form a negative electrode active material layer. The foil is then rolled and die-cut to form tabs, resulting in a negative electrode sheet.

[0092] The preparation method of the positive electrode sheet is as follows: A negative electrode active slurry (lithium iron phosphate) is coated on both sides of the positive electrode foil (aluminum foil), dried, and a positive electrode active material layer is formed. A boehmite ceramic slurry is coated on the side of the positive electrode active layer near the pre-set tab area to form an insulating layer. The foil is then rolled and die-cut to form tabs, resulting in the positive electrode sheet.

[0093] Test case The performance of the lithium-ion batteries prepared in each embodiment and comparative example was tested, as follows: 1. Capacity calibration test: ① First, discharge at a rate of 20A / h to 2.5V, let stand for 30 minutes, and record the discharge capacity; ②Then charge at a constant current and constant voltage of 20A / h to 3.65V, let stand for 30 minutes, and record the capacity; ③ Finally, discharge at a rate of 20A / h to 2.5V, let stand for 30 minutes, and record the discharge capacity as the capacity calibration value; 2. Perform heating and thermal runaway tests on the battery according to the GB44240-2024 test method. Table 3

[0094] Table 4

[0095] The results are shown in Table 5. As can be seen from Examples 1-18 and Comparative Example 1, by setting a support layer on the side of the active material layer away from the tab on the negative electrode sheet, although the battery capacity is slightly reduced due to the covering of a small part of the active material layer, the safety benefits brought far outweigh this capacity loss. Specifically, the design of the support layer can effectively play a supporting role, with strong structural stability, reduced separator shrinkage, and prevention of thermal runaway, thereby improving the safety performance and service life of the battery, which is of great significance.

[0096] The support layer width in Examples 6 and 15 is too low, the diaphragm shrinkage is good, and it can pass the heating test. However, the support insulation effect is low, and it is difficult to play a good role in preventing thermal runaway.

[0097] The support layer thickness in Examples 8 and 17 is relatively low, and the membrane shrinkage is good, so it can pass the heating test. However, the support and insulation effect is relatively low, making it difficult to play a good role in preventing thermal runaway. In addition, it is also easy for foreign objects to puncture.

[0098] The width of the support layer on the negative electrode sheet in Examples 7 and 16 is relatively high, which can better reduce the degree of membrane shrinkage and prevent thermal runaway. It can pass the heating test and thermal runaway test, but the capacity loss is relatively large.

[0099] The thickness of the support layer on the negative electrode sheet in Examples 9 and 18 is relatively high, which can better reduce the degree of diaphragm shrinkage and prevent thermal runaway. It can pass the heating test and thermal runaway test. However, it is easy to experience powder shedding after rolling during the preparation process.

[0100] Table 5

[0101] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. An electrode sheet, characterized in that, include: Extreme ear; A current collector is connected to the electrode tab, and an active material layer is provided on at least one side surface of the current collector; A support layer is disposed on the surface of the active material layer away from the tab and covers a portion of the active material layer.

2. The electrode sheet according to claim 1, characterized in that, The width of the support layer is 2 mm to 5 mm; And / or, the thickness of the support layer is 10 μm to 30 μm; And / or, the material of the support layer includes SiO2, alumina, and boehmite.

3. The electrode sheet according to claim 1, characterized in that, Further includes: An insulating layer is disposed between the tab and the active material layer, and does not cover or covers part of the active material layer.

4. The electrode sheet according to claim 3, characterized in that, The width of the insulating layer is 2 mm to 30 mm; And / or, the thickness of the insulating layer is 10 μm to 80 μm; And / or, the width of the overlap area between the insulating layer and the active material layer is 0 mm to 30 mm; And / or, the material of the support layer includes SiO2, alumina, boehmite, and boron nitride.

5. The electrode sheet according to claim 3 or 4, characterized in that, The width of the insulating layer is 2 mm to 5 mm; And / or, the thickness of the insulating layer is 10 μm to 30 μm; And / or, the width of the overlap area between the insulating layer and the active material layer is 0 mm to 2 mm.

6. The electrode sheet according to claim 1, characterized in that, The electrode sheet is selected from the negative electrode sheet, and the material of the current collector includes copper, copper alloy, nickel or nickel alloy.

7. The electrode sheet according to claim 1, characterized in that, The electrode sheet is selected from the positive electrode sheet, and the material of the current collector includes aluminum, aluminum alloy, nickel or nickel alloy.

8. A method for preparing the electrode sheet according to any one of claims 1-7, characterized in that, include: An active material layer is formed on at least one side surface of the current collector, and a tab setting area is pre-set on one side edge of the current collector; A support layer is formed on the side surface of the active material layer away from the tab setting area, covering a portion of the active material layer; A tab is disposed within the tab setting area to obtain the electrode sheet.

9. The method according to claim 8, characterized in that, include: An active material layer is formed on at least one side surface of the current collector, and a tab setting area is pre-set on one side edge of the current collector; On the surface of the active material layer, along the length direction of the current collector, the slurry of the support layer is applied and cured to form at least one support area. The support area does not coincide with the edge of the active material layer along the length direction of the current collector. A pre-set dividing line is provided within the support area. The dividing line extends along the length direction of the current collector and does not coincide with the edge of the support area. The current collector, active material layer, and support region are cut along the dividing line; A tab is disposed within the tab setting area to obtain at least two electrode plates.

10. The method according to claim 8, characterized in that, include: An active material layer is formed on at least one side surface of the current collector, and a tab setting area is pre-set on one side edge of the current collector; On the surface of the active material layer away from the tab placement area, a slurry of a support layer is applied to cover part of the active material layer and cured to form a support layer. A tab is disposed within the tab setting area to obtain the electrode sheet.

11. The method according to any one of claims 8-10, characterized in that, A slurry for applying the insulating layer is applied between the active material layer and the tab placement area and then cured to obtain the insulating layer, which may or may not cover a portion of the active material layer.

12. A battery, characterized in that, include: The electrode sheet according to any one of claims 1-7 or the electrode sheet obtained by the method of preparing the electrode sheet according to any one of claims 8-11.

13. A battery pack, characterized in that, include: The electrode sheet according to any one of claims 1-7 or the electrode sheet obtained by the method of preparing the electrode sheet according to any one of claims 8-11, and at least two batteries according to claim 12.

14. An electrical appliance, characterized in that, include: The electrode sheet according to any one of claims 1-7 or the electrode sheet obtained by the method of preparing the electrode sheet according to any one of claims 8-11, the battery according to claim 12, or the battery pack according to claim 13.

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