Positive electrode sheet, battery, and electrical device

Abstract

A positive electrode sheet, a battery, and an electrical device. The positive electrode sheet comprises a positive current collector, and an active material layer and a non-active material layer which are provided on at least one surface of the positive current collector; the non-active material layer surrounds the periphery of the active material layer; the active material layer comprises a positive electrode active material; and the active material layer and the non-active material layer are provided on the same layer. The positive electrode sheet is used for matching a lithium metal negative electrode in a lithium metal battery, so that a battery having high energy density and long cycle life can be obtained.

Description

Positive electrode, battery and electrical device

[0001] Cross-references

[0002] This application claims priority to Chinese Patent Application No. 202311277033.6, filed on September 28, 2023, entitled “Positive Electrode Sheet, Battery and Electrical Device,” which is incorporated herein by reference in its entirety. Technical Field

[0003] The present application relates to the field of battery technology, and in particular to a positive electrode sheet, a battery, and an electrical device. Background Art

[0004] In recent years, as the application scope of batteries has become more and more extensive, batteries have been widely used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, as well as in many fields such as power tools, electric bicycles, electric motorcycles and electric vehicles.

[0005] As batteries have made great progress, higher requirements have been placed on their energy density and cycle life. Therefore, seeking batteries with higher energy density and longer cycle life has become one of the key areas of focus for those skilled in the art.

[0006] Summary of the Invention

[0007] The present application is made in view of the above-mentioned problems, and one of its purposes is to provide a positive electrode plate, which can be used in a lithium metal battery in combination with a specific negative electrode plate to obtain a battery with higher energy density and longer cycle life.

[0008] In order to achieve the above-mentioned purpose, the first aspect of the present application provides a positive electrode plate, including a positive electrode current collector and an active material layer and an inactive material layer arranged on at least one surface of the positive electrode current collector, the inactive material layer is arranged around the periphery of the active material layer, the active material layer includes a positive electrode active material, and the active material layer and the inactive material layer are arranged in the same layer.

[0009] The present application arranges an inactive material layer around the periphery of the active material layer of the positive electrode sheet, and the active material layer and the inactive material layer are arranged in the same layer. When the positive electrode sheet is stacked with a lithium metal foil negative electrode sheet to form a battery, the orthographic projection of the edge of the lithium metal foil on the positive electrode sheet is located within the range of the inactive material layer. In this way, the situation in which the soft lithium metal foil is cut by the edge of the positive electrode sheet under pressure during the battery charging and discharging process, resulting in the loss of electrical connection of the negative electrode sheet, can be alleviated, thereby extending the cycle life of the battery using lithium metal foil as the negative electrode. In addition, by making the orthographic projection of the edge of the lithium metal foil on the positive electrode sheet located within the range of the inactive material layer, a region (i.e., an overhang region) in which the electrode portion extends beyond the range of the active material layer of the positive electrode sheet can be formed on the lithium metal foil, thereby reducing the growth of lithium dendrites at the edge of the lithium metal foil. By combining the positive electrode sheet with the lithium metal foil negative electrode, a battery with higher energy density and longer cycle life can be obtained.

[0010] In any embodiment, the inactive material layer comprises an insulating material, which may include one or more of an organic insulating material and an inorganic insulating material. Using an insulating material in the inactive material layer can mitigate the risk of short circuits between the positive and negative electrodes during battery production due to accidental bending of the electrode sheet or burrs on the positive electrode piercing the separator and contacting the negative electrode active material, thereby improving battery safety.

[0011] In any embodiment, the organic insulating material includes an organic polymer, including one or more of polymethyl methacrylate, polyimide, polyethylene, polypropylene, polytetrafluoroethylene, polyvinylidene fluoride, and polyvinylidene fluoride-hexafluoropropylene copolymer; and the inorganic insulating material includes oxide particles, including one or more of aluminum oxide particles and titanium oxide particles. The use of these organic and inorganic insulating materials can effectively mitigate positive and negative electrode short circuits.

[0012] In any embodiment, the thickness of the inactive material layer is equal to the thickness of the active material layer. This can alleviate the problem of uneven thickness on the positive electrode sheet and better alleviate the situation where the lithium metal foil is cut by the positive electrode sheet under pressure, resulting in loss of electrical connection of the negative electrode sheet.

[0013] In any embodiment, the thickness of the inactive material layer on the side closest to the active material layer is greater than the thickness on the side away from the active material layer. Thus, the greater thickness of the inactive material layer on the side closest to the active material layer can exert a certain pressure on the edge of the lithium metal foil, thereby pulverizing the deposited metallic lithium and alleviating the growth of lithium dendrites at the edge of the lithium metal foil. The smaller thickness of the inactive material layer on the side away from the active material layer is beneficial for improving the energy density of the battery.

[0014] In any embodiment, the thickness of the inactive material layer gradually decreases as it extends outward from the side of the inactive material layer closest to the active material layer. This can reduce the weight of the positive electrode sheet and further increase the energy density of the battery.

[0015] In any embodiment, the inactive material layer includes a first region and a second region, wherein the first region is adjacent to the active material layer, and the second region is located on the side of the first region facing away from the active material layer. The thickness of the inactive material layer in the first region is equal to the thickness of the active material layer; the thickness of the inactive material layer in the second region gradually decreases as it extends outward from the side adjacent to the first region. Thus, the thickness of the inactive material layer in the first region is designed to exert a certain pressure on the corresponding region of the lithium metal foil, thereby pulverizing the deposited metallic lithium and alleviating the growth of lithium dendrites on the lithium metal foil in this region. The thickness of the inactive material layer in the second region gradually decreases, which can further reduce the weight of the positive electrode sheet and increase the energy density of the battery.

[0016] In any embodiment, the positive electrode current collector includes a polymer support layer and a conductive layer disposed on at least one surface of the polymer support layer, and the active material layer and the inactive material layer are disposed on the surface of the conductive layer facing away from the polymer support layer. In this way, the positive electrode current collector uses a composite current collector, which can further improve the energy density of the battery.

[0017] The second aspect of the present application also provides a battery, including a stacked positive electrode sheet and a negative electrode sheet, the positive electrode sheet includes the positive electrode sheet of the first aspect of the present application, the negative electrode sheet includes a lithium metal foil, the lithium metal foil includes a plate portion and a tab lead portion connected to the plate portion, and the positive projection of the edge of the plate portion on the positive electrode sheet is located within the range of the inactive material layer.

[0018] The above-mentioned battery adopts the positive electrode plate of the first aspect of the present application, and adopts lithium metal foil as the negative electrode plate, and the orthographic projection of the edge of the plate portion on the positive electrode plate is located within the range of the inactive material layer; during the battery charging and discharging process, even if the positive electrode plate is close to the negative electrode plate under pressure, the edge of the positive electrode plate will not cause cutting of the negative electrode lithium metal foil, which can alleviate the situation where the soft lithium metal foil is cut by the edge of the positive electrode plate under pressure during the battery charging and discharging process, resulting in the loss of electrical connection of the negative electrode plate, and can extend the cycle life of the battery; and the battery has a high energy density.

[0019] In any embodiment, the distance between the orthographic projection of the electrode portion edge on the positive electrode sheet and the outer edge of the inactive material layer is a, and a is 1 mm to 5 mm; alternatively, a is 1.5 mm to 3 mm. This effectively reduces the risk of the electrode portion being cut by the edge of the positive electrode sheet and prevents the positive electrode sheet from being too wide, thereby affecting the battery's energy density.

[0020] In any embodiment, the orthographic projection of the active material layer on the negative electrode is located within the electrode portion. In this way, an overhang region can be formed at the edge of the electrode portion, alleviating the growth of lithium dendrites at the edge of the electrode portion and improving battery safety.

[0021] In any embodiment, the distance between the orthographic projection of the edge of the pole piece on the positive electrode sheet and the outer edge of the active material layer is b, and b is 1 mm to 5 mm; alternatively, b is 1.5 mm to 3 mm. This effectively mitigates the growth of lithium dendrites at the edge of the pole piece, improving battery safety, while also limiting the width of the overhang area, which is beneficial for improving battery energy density.

[0022] In any embodiment, the inactive material layer includes a first region and a second region, the first region being adjacent to the active material layer and the second region being located on a side of the first region facing away from the active material layer. The thickness of the inactive material layer in the second region gradually decreases as it extends outward from the side adjacent to the first region. The thickness of the inactive material layer in the first region is equal to the thickness of the active material layer, and the width of the first region is ≥ b. Thus, the design of the thickness of the inactive material layer in the first region and the width of the first region can exert a certain pressure on the corresponding region of the lithium metal foil, thereby pulverizing the deposited metallic lithium and mitigating the growth of lithium dendrites on the lithium metal foil in this region. The gradually decreasing thickness of the inactive material layer in the second region can further mitigate the risk of the lithium metal foil being cut by the positive electrode sheet under pressure, further reducing the weight of the positive electrode sheet and increasing the battery energy density.

[0023] In any embodiment, the orthographic projection of the outer edge of the tab lead portion on the positive electrode sheet is located within the range of the inactive material layer. This can reduce the risk of the tab lead portion being cut by the edge of the positive electrode sheet under pressure during battery charging and discharging, further improving the cycle life of the battery.

[0024] In any embodiment, the tab lead portion is provided with a tab lead foil composited with the lithium metal foil, with a tab connector connected to the tab lead foil. This allows the negative electrode tab to be welded to the tab connector, significantly reducing the difficulty of negative electrode tab lead-out and welding. Furthermore, the tab lead foil composited with the lithium metal foil in the tab lead portion can serve to collect current and improve the strength of the tab lead portion.

[0025] In any embodiment, the width of the tab connection sheet is c, the length of the tab lead foil is d, and the width of the lithium metal foil at one end near the tab connection sheet is e, where c ≤ d ≤ e. Optionally, d = e. In this manner, the longer tab lead foil increases the combined contact area between the tab lead foil and the lithium metal foil, further facilitating current convergence and reducing overcurrent.

[0026] In any embodiment, the thickness of the lithium metal foil is 10 μm to 50 μm, and can be 30 μm to 50 μm, which is beneficial for the battery to have a higher energy density and a longer cycle life.

[0027] The third aspect of the present application further provides an electrical device, which includes the battery of the second aspect of the present application.

[0028] The details of one or more embodiments of the present application are set forth in the following drawings and description. Other features, objects, and advantages of the present application will become apparent from the description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to better describe and illustrate the embodiments or examples provided in this application, reference may be made to one or more of the accompanying drawings. The additional details or examples used to describe the accompanying drawings should not be considered as limiting the scope of the disclosed application, the embodiments or examples currently described, and any of the best modes currently understood for these applications. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the accompanying drawings:

[0030] FIG1 is a schematic front view of a positive electrode sheet according to an embodiment of the present application;

[0031] FIG2 is a schematic cross-sectional view of a positive electrode sheet according to an embodiment of the present application;

[0032] FIG3 is a schematic cross-sectional view of a positive electrode sheet according to another embodiment of the present application;

[0033] FIG4 is a schematic cross-sectional view of a positive electrode sheet according to another embodiment of the present application;

[0034] FIG5 is a schematic cross-sectional view of a positive electrode current collector in one embodiment of the present application;

[0035] FIG6 is a front view schematic diagram of the stacked positive electrode sheet and the negative electrode sheet in a battery according to one embodiment of the present application;

[0036] FIG7 is a front view schematic diagram of the stacked positive electrode sheet and the negative electrode sheet in a battery according to another embodiment of the present application;

[0037] FIG8 is a schematic cross-sectional view of a stacked positive electrode sheet and a negative electrode sheet in a battery according to an embodiment of the present application;

[0038] FIG9 is a cross-sectional schematic diagram of a stacked positive electrode sheet and a negative electrode sheet in a battery according to another embodiment of the present application;

[0039] FIG10 is a cross-sectional schematic diagram of a stacked positive electrode sheet and a negative electrode sheet in a battery according to another embodiment of the present application;

[0040] FIG11 is a schematic front view of a negative electrode sheet in a battery according to an embodiment of the present application;

[0041] FIG12 is a side view of a negative electrode tab connector of a battery in accordance with an embodiment of the present application when not sheared;

[0042] FIG13 is a front view of a battery according to an embodiment of the present application, wherein the tab connecting piece of the negative electrode is not sheared;

[0043] FIG14 is a schematic diagram of a battery cell according to an embodiment of the present application;

[0044] FIG15 is an exploded view of the battery cell according to one embodiment of the present application shown in FIG14 ;

[0045] FIG16 is a schematic diagram of an electrical device using a battery as a power source according to an embodiment of the present application.

[0046] Description of reference numerals:

[0047] 5. Battery cell; 51. Casing; 52. Electrode assembly; 53. Cover plate; 6. Electrical device; 10. Positive electrode plate; 11. Positive current collector; 12. Active material layer; 13. Inactive material layer; 111. Polymer support layer; 112. Conductive layer; 131. First region; 132. Second region; 20. Negative electrode plate; 21. Lithium metal foil; 22. Tab lead-out foil; 23. Tab connecting piece; 211. Pole piece portion; 212. Tab lead-out portion. DETAILED DESCRIPTION

[0048] Below, the embodiments of the positive electrode sheet, battery, and electrical device of the present application are described in detail with appropriate reference to the accompanying drawings. However, there may be cases where unnecessary detailed descriptions are omitted. For example, there may be cases where detailed descriptions of well-known matters and repeated descriptions of actually the same structure are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0049] The "ranges" disclosed in this application can be defined in the form of lower limits and upper limits. A given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of the particular range. Ranges defined in this way can be inclusive or exclusive of the end values, any end value can be included or excluded independently, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60 to 120 and 80 to 110 are listed for a particular parameter, it is understood that ranges of 60 to 110 and 80 to 120 are also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4, and 5 are also listed, the following ranges are all expected: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, and 2 to 5. In this application, unless otherwise specified, the numerical range "a to b" is an abbreviation for any combination of real numbers between a and b, where a and b are both real numbers. For example, a numerical range of "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is merely an abbreviation for a combination of these values. Furthermore, when a parameter is expressed as an integer greater than or equal to 2, this is equivalent to listing the parameter as, for example, the integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and so on. For example, when a parameter is expressed as an integer selected from "2-10," this is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0050] In this application, "a plurality of" or "a plurality of" refers to a number greater than or equal to 2 unless otherwise specified. For example, "one or more" means one or more than or equal to two.

[0051] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0052] References to "embodiments" herein mean that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment or implementation of the present application. The appearance of such phrases in various locations in the specification does not necessarily refer to the same embodiment, nor does it necessarily refer to independent or alternative embodiments that are mutually exclusive with other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments. References to "implementations" herein have a similar understanding.

[0053] It will be appreciated by those skilled in the art that, in the methods of various embodiments or examples, the order in which the steps are written does not imply a strict order of execution and does not constitute any limitation on the implementation process, and the detailed order of execution of each step should be determined by its function and possible inherent logic. Unless otherwise specified, all steps of the present application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or steps (b) and (a) performed sequentially. For example, the method may further include step (c), indicating that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0054] In this application, in the open technical features or technical solutions described with words such as "contain", "include", and "include", unless otherwise specified, additional members other than the listed members are not excluded, and it can be regarded as providing both closed features or solutions consisting of the listed members and open features or solutions that also include additional members in addition to the listed members. For example, A includes a1, a2, and a3. Unless otherwise specified, it may also include other members or may not include additional members. It can be regarded as providing both the feature or solution of "A consists of a1, a2, and a3" and the feature or solution of "A includes not only a1, a2, and a3, but also other members". In this application, unless otherwise specified, A (such as B) means that B is a non-limiting example of A, and it can be understood that A is not limited to B.

[0055] In this application, the terms "optionally," "optional," and "optional" are optional and refer to either option being present or absent. If a technical solution contains multiple "options," each option is considered independent unless otherwise specified and there are no conflicts or constraints.

[0056] The weights described in the examples of this application may be weight units known in the chemical industry, such as μg, mg, g, and kg.

[0057] Currently, due to the rapid development of batteries, higher requirements have been placed on their energy density and cycle life. Therefore, the search for batteries with higher energy density and longer cycle life is one of the key areas of focus for those skilled in the art. In this regard, the present application provides a positive electrode sheet. By improving the structure of the positive electrode sheet and combining it with a lithium metal negative electrode, a battery with higher energy density and longer cycle life can be obtained.

[0058] Referring to Figures 1 to 4, in some embodiments, the first aspect of the present application provides a positive electrode plate 10, which includes a positive electrode current collector 11 and an active material layer 12 and an inactive material layer 13 disposed on at least one surface of the positive electrode current collector 11. The inactive material layer 13 is disposed around the periphery of the active material layer 12, the active material layer 12 includes a positive electrode active material, and the inactive material layer 13 does not include a positive electrode active material.

[0059] Lithium metal anode is the ultimate anode solution for achieving ultra-high energy density lithium-ion batteries. Using lithium metal as the anode can achieve higher energy density than using graphite and other anode active materials. The lithium metal anode used in current lithium metal batteries is usually formed by covering ultra-thin lithium foil on copper foil, where the copper foil is used to provide current and as a substrate to provide mechanical support and strength for the lithium metal foil. However, the density of copper foil (about 8.92g / cm 2 ) is the density of lithium metal (about 0.53g / cm 2 ) is nearly 17 times greater than the lithium metal foil. This means that when pursuing the ultimate high energy density, the weight of copper foil is a significant factor. If copper foil can be completely eliminated as the negative electrode substrate, the battery's energy density can be further improved. At the same time, the thickness of the lithium metal foil can also be designed to provide more space, supporting longer cycle consumption and extending the cycle life of the lithium metal battery.

[0060] However, the negative electrode does not use a copper foil substrate and lithium metal foil to laminate, but directly uses lithium metal foil as the negative electrode plate, which needs to overcome the following problems: the lithium metal foil itself is soft and has poor strength. During the battery charging and discharging process, the lithium metal foil is very easily cut by the edge of the positive electrode under pressure, causing the lithium metal foil to lose electrical contact with the negative electrode tab, thereby causing battery failure and a short battery cycle life.

[0061] In response to the above problems, the present application arranges an inactive material layer 13 around the periphery of the active material layer 12 of the positive electrode plate 10, and the active material layer 12 and the inactive material layer 13 are arranged in the same layer, and the inactive material layer 13 does not include the positive electrode active material; when the positive electrode plate 10 is stacked with the lithium metal foil negative electrode plate to form a battery, the orthographic projection of the edge of the electrode portion 211 of the lithium metal foil 21 on the positive electrode plate 10 is located within the range of the inactive material layer 13, that is, the inactive material layer 13 can cover the edge of the electrode portion 211; in this way, even if the positive electrode plate approaches the negative electrode plate under pressure during the battery charging and discharging process, the edge of the positive electrode plate will not cut the negative electrode lithium metal foil, which can alleviate the situation where the soft lithium metal foil is cut by the edge of the positive electrode plate under pressure during the battery charging and discharging process, resulting in the loss of electrical connection of the negative electrode plate, thereby extending the cycle life of the battery using lithium metal foil as the negative electrode. By combining the positive electrode sheet with a lithium metal foil negative electrode, a battery with higher energy density and longer cycle life can be obtained.

[0062] In some embodiments, the material of the inactive material layer 13 includes an insulating material, which includes one or more of an organic insulating material and an inorganic insulating material. The use of an insulating material as the material of the inactive material layer 13 can alleviate the situation in which the positive and negative electrodes are short-circuited due to accidental bending of the electrode piece or the positive electrode burr piercing the separator and overlapping the negative electrode active material during the battery production process. By using an insulating material as the inactive material layer 13, even if the electrode piece is bent or the positive electrode burr pierces the separator and overlaps the negative electrode active material, it will not cause the positive and negative electrodes to be conductive, and the positive and negative electrodes will not short-circuit, which can improve the safety of the battery.

[0063] In some embodiments, the insulating material of the inactive material layer 13 includes one or more of polymethyl methacrylate (PMMA), polyimide (PI), polyethylene (PE), polypropylene (PP), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), aluminum oxide particles, and titanium oxide particles. The use of the above-mentioned insulating materials can effectively alleviate the short circuit of the positive and negative electrodes. Among the above-mentioned insulating materials, polymethyl methacrylate, polyimide, polyethylene, polypropylene, polytetrafluoroethylene, polyvinylidene fluoride, and polyvinylidene fluoride-hexafluoropropylene copolymer are organic polymer insulating materials that can be formed on the positive electrode collector 11 by gluing or slurry coating; aluminum oxide particles and titanium oxide particles are inorganic particle insulating materials that can be formed on the positive electrode collector 11 by slurry coating. The particle size of the aluminum oxide particles and titanium oxide particles can be nanometer-scale or micrometer-scale.

[0064] It can be understood that the inactive material layer 13 can be formed by using one or more of the above-mentioned insulating polymers, or by using one or more of the above-mentioned insulating inorganic particles. The inactive material layer 13 can also be formed by mixing the above-mentioned one or more polymers with the above-mentioned one or more inorganic particles.

[0065] Referring to FIG. 2 , in some embodiments, the thickness of the inactive material layer 13 is equal to the thickness of the active material layer 12. By setting the thickness of the inactive material layer 13 to be equal to the thickness of the active material layer 12, the uneven thickness of the positive electrode sheet 10 can be alleviated, and the situation in which the lithium metal foil is cut by the positive electrode sheet under pressure, resulting in loss of electrical connection of the negative electrode sheet, can be better alleviated.

[0066] In some embodiments, the thickness of the inactive material layer 13 on the side closer to the active material layer 12 is greater than the thickness of the inactive material layer 13 on the side farther from the active material layer 12. Thus, the thicker side of the inactive material layer 13 closer to the active material layer 12 can exert a certain pressure on the edge of the lithium metal foil 21, thereby pulverizing the deposited metallic lithium and alleviating the growth of lithium dendrites at the edge of the lithium metal foil 21. The thinner side of the inactive material layer 13 farther from the active material layer 12 is beneficial for improving the energy density of the battery.

[0067] Referring to Figure 3 , in some embodiments, the thickness of the inactive material layer 13 gradually decreases as it extends outward from the side of the inactive material layer 13 closest to the active material layer 12. This allows the inactive material layer 13 to have a greater thickness near the active material layer 12, further mitigating the growth of lithium dendrites at the edge of the lithium metal foil 21. Furthermore, the thickness of the inactive material layer 13 near the edge of the positive electrode sheet 10 can be reduced, further reducing the weight of the positive electrode sheet 10 and thereby increasing the energy density of the battery.

[0068] It can be understood that the thickness of the inactive material layer 13 can be in a straight line, a curve, or a gradient, gradually decreasing in a direction extending outward from the side of the inactive material layer 13 close to the active material layer 12 .

[0069] Referring to FIG. 4 , in some embodiments, the inactive material layer 13 includes a first region 131 and a second region 132. The first region 131 is adjacent to the active material layer 12, and the second region 132 is located on the side of the first region 131 facing away from the active material layer 12. The thickness of the inactive material layer 13 in the first region 131 is equal to that of the active material layer 12. The thickness of the inactive material layer 13 in the second region 132 gradually decreases as it extends outward from the side adjacent to the first region 131.

[0070] Because lithium dendrites are prone to growing at the edge of the negative electrode lithium metal foil, corresponding to the area near the active material layer 12, by setting the thickness of the inactive material layer 13 in the first area 131 of the positive electrode sheet 10 near the active material layer 12 to be equal to the thickness of the active material layer 12, the inactive material layer 13 in the first area 131 can apply a certain amount of pressure to the corresponding area of ​​the lithium metal foil, thereby pulverizing the deposited metallic lithium and alleviating the growth of lithium dendrites on the lithium metal foil in this area. In addition, the thickness of the inactive material layer 13 in the second area 132 is gradually reduced in a direction extending outward from the side near the first area 131, which is further conducive to reducing the weight of the positive electrode sheet 10 and increasing the energy density of the battery.

[0071] It is understandable that the thickness of the inactive material layer 13 in the second region 132 may be in a straight line, a curve, or a gradient, gradually decreasing in a direction extending outward from the side close to the first region 131 .

[0072] Referring to FIG. 5 , in some embodiments, the positive electrode current collector 11 includes a polymer support layer 111 and a conductive layer 112 disposed on at least one surface of the polymer support layer 111. The active material layer 12 and the inactive material layer 13 are disposed on a surface of the conductive layer 112 facing away from the polymer support layer 111. Thus, the positive electrode current collector 11 uses a composite current collector, and an ultra-thin conductive layer 112 can be used, which can further improve the energy density of the battery.

[0073] It should be noted that the material of the polymer support layer 111 can be, but is not limited to, one or more of polyethylene terephthalate (PET), polyimide (PI), polystyrene (PS), polyethylene (PE), polypropylene (PP), polycarbonate (PC), polyvinyl chloride (PET), and polymethyl methacrylate (PMMA). The thickness of the polymer support layer 111 can be 1 μm to 20 μm; in order to further improve the energy density of the battery, the thickness of the polymer support layer 111 can be 1 μm to 5 μm. The material of the conductive layer 112 can be metallic aluminum, and the conductive layer 112 can be formed on the surface of the polymer support layer 111 by magnetron sputtering or evaporation. The thickness of the conductive layer 112 can be 0.5 μm to 5 μm. In order to further improve the energy density of the battery, the thickness of the conductive layer 112 can be 0.5 μm to 2 μm.

[0074] In some embodiments, the above-mentioned positive electrode plate 10 can be prepared by the following method: providing a polymer support layer 111, forming a conductive layer 112 on the surface of the polymer support layer 111 by magnetron sputtering or evaporation, etc., to obtain a positive electrode current collector 11; attaching a positive electrode slurry to the conductive layer 112 of the positive electrode current collector 11 to form a positive electrode slurry layer, wherein the positive electrode slurry includes a positive electrode active material; drying the positive electrode slurry layer to form an active material layer 12; forming an inactive material layer 13 on the conductive layer 112 by gluing or slurry coating, so that the inactive material layer 13 is arranged around the active material layer 12, thereby obtaining the positive electrode plate 10.

[0075] Referring to Figures 6 to 10 , in some embodiments, the second aspect of the present application provides a battery comprising a stacked positive electrode sheet 10 and a negative electrode sheet 20 . The positive electrode sheet 10 is the positive electrode sheet 10 of the first aspect of the present application, and the negative electrode sheet 20 is a lithium metal foil 21 ; the lithium metal foil 21 includes a tab portion 211 and a tab lead portion 212 connected to the tab portion 211 , and the orthographic projection of the edge of the tab portion 211 on the positive electrode sheet 10 is located within the range of the inactive material layer 13 .

[0076] The above-mentioned battery adopts the positive electrode plate 10 of the first aspect of the present application, adopts the lithium metal foil 21 as the negative electrode plate 20, and makes the orthographic projection of the edge of the plate portion 211 on the positive electrode plate 10 be located within the range of the inactive material layer 13; during the battery charging and discharging process, even if the positive electrode plate 10 is close to the negative electrode plate 20 under pressure, the edge of the positive electrode plate 10 will not cause cutting to the negative electrode lithium metal foil 21, which can alleviate the situation in which the soft lithium metal foil 21 is cut by the edge of the positive electrode plate 10 under pressure during the battery charging and discharging process, resulting in the loss of electrical connection of the negative electrode plate 20, and can extend the cycle life of the battery; and the battery has a high energy density.

[0077] If the orthographic projection of the edge of the pole piece 211 on the positive electrode plate 10 is outside the range of the inactive material layer 13, that is, the edge of the pole piece 211 is located outside the inactive material layer 13, and the inactive material layer 13 cannot cover the edge of the pole piece 211; then since the pole piece 211 of the lithium metal foil 21 is soft in texture, the pole piece 211 is easily cut by the edge of the positive electrode plate 10 under pressure during the battery charging and discharging process, affecting the cycle life of the battery.

[0078] Referring to Figure 6 , in some embodiments, the distance between the orthographic projection of the edge of the electrode portion 211 of the lithium metal foil 21 on the positive electrode sheet 10 and the outer edge of the inactive material layer 13 is a, and a = 1mm to 5mm. In this way, the outer edge of the inactive material layer 13 extends beyond the edge of the electrode portion 211 by 1mm to 5mm, effectively preventing the electrode portion 211 from being cut by the edge of the positive electrode sheet 10 and preventing the positive electrode sheet 10 from being too wide, which would affect the battery's energy density.

[0079] It will be understood that a can be, but is not limited to, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2.0mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3.0mm, 3.1mm, 3.2mm, 3.3mm, 3.4mm, 3.5mm, 3.6mm, 3.7mm, 3.8mm, 3.9mm, 4.0mm, 4.1mm, 4.2mm, 4.3mm, 4.4mm, 4.5mm, 4.6mm, 4.7mm, 4.8mm, 4.9mm, and 5.0mm.

[0080] In some embodiments, the distance a between the orthographic projection of the edge of the electrode portion 211 of the lithium metal foil 21 on the positive electrode sheet 10 and the outer edge of the inactive material layer 13 is 1.5 mm to 3 mm. This can better reduce the risk of the electrode portion 211 being cut by the edge of the positive electrode sheet 10 and further improve the energy density of the battery.

[0081] Referring to Figures 6 and 7, in some embodiments, the orthographic projection of the active material layer 12 on the negative electrode plate 20 is located within the range of the plate portion 211, that is, the range of the plate portion 211 can cover the range of the active material layer 12. In this way, an overhang region can be formed at the edge of the plate portion 211, alleviating the growth of lithium dendrites at the edge of the plate portion 211 and improving the safety of the battery. It should be noted that the overhang region refers to the area where the plate portion 211 extends beyond the active material layer 12.

[0082] Referring to Figure 6 , in some embodiments, the distance b between the orthographic projection of the edge of the electrode portion 211 on the positive electrode sheet 10 and the outer edge of the active material layer 12 is 1 mm to 5 mm. This effectively mitigates the formation of lithium dendrites at the edge of the electrode portion 211, improving battery safety, while also limiting the width of the overhang area, thereby increasing battery energy density.

[0083] It will be understood that b can be, but is not limited to, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2.0mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3.0mm, 3.1mm, 3.2mm, 3.3mm, 3.4mm, 3.5mm, 3.6mm, 3.7mm, 3.8mm, 3.9mm, 4.0mm, 4.1mm, 4.2mm, 4.3mm, 4.4mm, 4.5mm, 4.6mm, 4.7mm, 4.8mm, 4.9mm, and 5.0mm.

[0084] In some embodiments, the distance b between the orthographic projection of the edge of the electrode portion 211 on the positive electrode plate 10 and the outer edge of the active material layer 12 is 1.5 mm to 3 mm. This can better alleviate the growth of lithium dendrites at the edge of the electrode portion 211 and further improve the energy density of the battery.

[0085] Referring to Figure 10 , in some embodiments, the inactive material layer 13 includes a first region 131 and a second region 132. The first region 131 is located adjacent to the active material layer 12, and the second region 132 is located on a side of the first region 131 facing away from the active material layer 12. Furthermore, the thickness of the inactive material layer 13 in the second region 132 gradually decreases as it extends outward from the side adjacent to the first region 131. The thickness of the inactive material layer 13 in the first region 131 is equal to the thickness of the active material layer 12, and the width of the first region 131 is ≥ b.

[0086] By adopting the above-mentioned setting, the width of the first region 131 is set to ≥ b, so that the first region 131 can cover the overhang area at the edge of the electrode portion 211; and the thickness of the inactive material layer 13 in the first region 131 is equal to the thickness of the active material layer 12. During the battery charging and discharging process, the inactive material layer 13 in the first region 131 can apply pressure to the overhang area, causing the metallic lithium deposited in the overhang area to be powdered, which is more conducive to inhibiting the growth of lithium dendrites. In addition, the thickness of the inactive material layer 13 in the second region 132 is gradually reduced in the direction extending outward from the side close to the first region 131, which can further alleviate the electrode portion 211 from being cut by the edge of the positive electrode plate 10 under pressure, and can reduce the weight of the positive electrode plate 10 and improve the energy density of the battery.

[0087] Referring to Figures 11 to 13 , in some embodiments, a tab lead-out portion 212 is provided with a tab lead-out foil 22 composited with the lithium metal foil 21, to which a tab connector 23 is connected. In addition to the fact that the lithium metal foil 21 is easily cut by the edge of the positive electrode under pressure, batteries using the lithium metal foil 21 as the negative electrode plate 20 also have the problem of difficulty in leading out and welding the negative electrode tab. To address this issue, the present application provides a tab lead-out portion 212 on the lithium metal foil 21, on which a tab lead-out foil 22 composited with the lithium metal foil 21 is provided, to which a tab connector 23 is connected. This allows the negative electrode tab to be welded to the tab connector 23, greatly reducing the difficulty of leading out and welding the negative electrode tab. The tab lead foil 22 and the lithium metal foil 21 of the tab lead portion 212 are combined to collect current and improve the strength of the tab lead portion 212 .

[0088] It is understood that the tab lead-out foil 22 needs to be a metal foil with good conductivity. As a specific example, the tab lead-out foil 22 can be a copper foil.

[0089] In some embodiments, the tab lead portion 212 is located at one end of the pole piece portion 211. The width f of the tab lead portion 212 can be 1 mm to 10 mm, optionally 1 mm to 3 mm. The thickness of the tab lead foil 22 can be 2 μm to 20 μm, optionally 2 μm to 5 μm. The width of the lithium metal foil 21 can be 10 mm to 500 mm. The thickness of the lithium metal foil 21 can be 5 μm to 200 μm, optionally 10 μm to 50 μm, and further 30 μm to 50 μm. When the thickness of the lithium metal foil 21 is within this range, the battery can have a higher energy density and a longer cycle life.

[0090] In some embodiments, the tab lead-out foil 22 of the tab lead-out portion 212 can be applied to the lithium metal foil 21 by rolling. Specifically, the tab lead-out foil 22 can be sandwiched between two lithium metal foils 21, and the two lithium metal foils 21 and the tab lead-out foil 22 can be rolled together under heating conditions (see Figure 12). Since the lithium metal foil 21 has good ductility under heating conditions, it can ensure that the tab lead-out foil 22 is sandwiched in the middle without generating a thickness difference at the junction of the tab lead-out portion 212 and the pole piece portion 211, and will not affect the thickness uniformity of the battery cell edge. When rolling and laminating the tab lead-out foil 22, a portion of the tab lead-out foil 22 can be extended outside the lithium metal foil 21 to form a blank area at one end (see Figure 13). After rolling and laminating, the blank area can be cut according to the required size to form the tab connecting piece 23. In this way, the tab connecting piece 23 and the tab lead-out foil 22 are an integrated structure.

[0091] Please refer to Figure 7. In some embodiments, the orthographic projection of the outer edge of the tab lead-out portion 212 on the positive electrode sheet 10 is located within the range of the inactive material layer 13. Although the strength of the tab lead-out portion 212 is improved compared to the strength of the pure lithium metal foil 21 due to the covering of the tab lead-out foil 22, the possibility of the tab lead-out portion 212 being cut by the edge of the positive electrode sheet 10 cannot be ruled out when the thickness of the tab lead-out foil 22 is relatively thin. To this end, by ensuring that the orthographic projection of the outer edge of the tab lead-out portion 212 on the positive electrode sheet 10 is within the range of the inactive material layer 13, that is, the inactive material layer 13 can cover the outer edge of the tab lead-out portion 212, this can alleviate the tab lead-out portion 212 from being cut by the edge of the positive electrode sheet 10 under pressure during the battery charging and discharging process, thereby further improving the cycle life of the battery.

[0092] Referring to Figure 11 , in some embodiments, the width of the tab connecting piece 23 is c, the length of the tab lead foil 22 is d, and the width of the lithium metal foil 21 near the tab connecting piece 23 is e, where c≤d≤e. That is, the length of the tab lead foil 22 is greater than or equal to the width of the tab connecting piece 23 and less than or equal to the width of the lithium metal foil 21 near the tab connecting piece 23. Generally speaking, the length of the tab lead foil 22 should be set longer to better facilitate current collection. In one specific example, the length of the tab lead foil 22 is equal to the width of the lithium metal foil 21 near the tab connecting piece 23.

[0093] In some embodiments, the third aspect of the present application provides an electrical device, which includes the battery of the second aspect of the present application.

[0094] The battery and the electrical device of the present application will be described below with reference to the accompanying drawings as appropriate.

[0095] Unless otherwise specified, the components, material types or contents of the batteries mentioned apply to both lithium-ion batteries and sodium-ion batteries.

[0096] In one embodiment of the present application, a battery is provided.

[0097] Typically, a battery consists of a positive electrode, a negative electrode, an electrolyte, and a separator. During the battery's charge and discharge processes, active ions are inserted and removed between the positive and negative electrodes. The electrolyte conducts ions between the positive and negative electrodes. The separator, located between the positive and negative electrodes, primarily prevents short circuits between the positive and negative electrodes while allowing ions to pass through.

[0098] Positive electrode

[0099] The positive electrode sheet includes a positive electrode current collector and an active material layer disposed on at least one surface of the positive electrode current collector.

[0100] As a non-limiting example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the active material layer is provided on either or both of the two facing surfaces of the positive electrode current collector.

[0101] In some embodiments, the positive electrode sheet adopts the positive electrode sheet of the first aspect of the present application.

[0102] In some embodiments, the positive electrode current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. The composite current collector may be obtained by forming a metal material on a polymer material substrate. In the positive electrode current collector, non-limiting examples of the metal material may include one or more of aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy. In the positive electrode current collector, non-limiting examples of the polymer material substrate may include one or more of substrates such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.

[0103] In some embodiments, the positive electrode active material may include a positive electrode active material for a battery known in the art.

[0104] As a non-limiting example, the positive electrode active material of the lithium-ion battery may include one or more of the following materials: lithium-containing phosphates with an olivine structure, lithium transition metal oxides and their respective modified compounds. However, the present application is not limited to these materials, and other traditional 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. Among them, examples of lithium transition metal oxides may include, but are not limited to, one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide and their modified compounds. Non-limiting examples of lithium-containing phosphates with an olivine structure may include, but are not limited to, one or more of lithium iron phosphate, a composite material of lithium iron phosphate and carbon, lithium manganese phosphate, a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite material of lithium manganese iron phosphate and carbon. Non-limiting examples of lithium cobalt oxide may include LiCoO2; non-limiting examples of lithium nickel oxide may include LiNiO2; non-limiting examples of lithium manganese oxide may include LiMnO2, LiMn2O4, etc.; non-limiting examples of lithium nickel cobalt manganese oxide may include LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also referred to as NCM 333 ), LiNi0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ) etc.; Non-limiting examples of lithium nickel cobalt aluminum oxide may include LiNi 0.8 Co 0.15 Al 0.05 O2.

[0105] It is understandable that the battery will be accompanied by lithium (Li) deintercalation and consumption during the charge and discharge process, and the content of Li in the positive electrode plate is different when the battery is discharged to different states. In the list of positive electrode materials in this application, unless otherwise specified, the Li content is the initial state of the material. The positive electrode material is applied to the positive electrode plate in the battery system, and after the charge and discharge cycle, the Li content in the positive electrode material contained in the plate will usually change. Among them, the Li content can be measured by molar content, but is not limited to this. Regarding "the Li content is the initial state of the material", the initial state of the material refers to the state before the material is added to the positive electrode slurry. It is understandable that new materials obtained by appropriate modification on the basis of the listed positive electrode materials are also within the scope of positive electrode materials. The aforementioned appropriate modification refers to acceptable modification methods for positive electrode materials, and non-limiting examples include coating modification.

[0106] In the examples of positive electrode materials in this application, the oxygen (O) content is only a theoretical value. Lattice oxygen release will cause the molar content of oxygen to change, and the actual O content will fluctuate. The O content can be measured by molar content, but is not limited to this.

[0107] As non-limiting examples, the positive electrode active material of a sodium ion battery may include one or more of the following materials: sodium transition metal oxides, polyanionic compounds, and Prussian blue compounds. However, the present application is not limited to these materials, and other conventionally known materials that can be used as positive electrode active materials for sodium ion batteries may also be used.

[0108] As an optional technical solution of the present application, in the sodium transition metal oxide, the transition metal can be one or more of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr and Ce. Sodium transition metal oxide is, for example, Na x MO2, wherein M is one or more of Ti, V, Mn, Co, Ni, Fe, Cr and Cu, and 0<x≤1.

[0109] As an optional technical solution of the present application, the polyanionic compound can be a compound having sodium ions, transition metal ions and tetrahedral (YO4) n- A class of compounds with anionic units. The transition metal can be one or more of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr and Ce; Y can be one or more of P, S and Si; n represents (YO4) n- valence.

[0110] Polyanionic compounds can also be sodium ions, transition metal ions, tetrahedral (YO4) n- A class of compounds containing anion units and halogen anions. The transition metal can be one or more of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr, and Ce; Y can be one or more of P, S, and Si, and n represents (YO4) n- valence state; the halogen can be one or more of F, Cl and Br.

[0111] Polyanionic compounds can also be sodium ions, tetrahedral (YO4) n- Anion unit, polyhedron unit (ZO y ) m+ and an optional halogen anion. Y can be one or more of P, S and Si, and n represents (YO4) n- valence state; Z represents a transition metal, which can be one or more of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr and Ce, m represents (ZO y ) m+ valence state; the halogen can be one or more of F, Cl and Br.

[0112] Polyanionic compounds include NaFePO4, Na3V2(PO4)3 (sodium vanadium phosphate, abbreviated as NVP), Na4Fe3(PO4)2(P2O7), NaM'PO4F (M' is one or more of V, Fe, Mn and Ni) and Na3(VO y )2(PO4)2F 3-2y One or more of (0≤y≤1).

[0113] Prussian blue compounds can be sodium ions, transition metal ions and cyanide ions (CN - ) compounds. The transition metal can be one or more of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr and Ce. Prussian blue compounds are, for example, Na a Me b Me' c (CN)6, wherein Me and Me' are each independently one or more of Ni, Cu, Fe, Mn, Co and Zn, 0<a≤2, 0<b<1, 0<c<1.

[0114] The weight ratio of the positive electrode active material in the active material layer is 80 wt % to 100 wt % based on the total weight of the active material layer.

[0115] In some embodiments, the active material layer may further optionally include a binder. As a non-limiting example, the binder may include one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylate resin. The weight ratio of the binder in the active material layer is 0% to 20% by weight, based on the total weight of the active material layer.

[0116] In some embodiments, the active material layer may further optionally include a conductive agent. As non-limiting examples, the conductive agent may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. The weight ratio of the conductive agent in the active material layer is 0% to 20% by weight, based on the total weight of the active material layer.

[0117] In some embodiments, the positive electrode sheet can be prepared by the following method: the components for preparing the positive electrode sheet, such as the positive electrode active material, the conductive agent, the binder and any other components, are dispersed in a solvent (such as N-methylpyrrolidone) to form a positive electrode slurry, wherein the positive electrode slurry has a solid content of 40wt% to 80wt%, and the viscosity at room temperature is adjusted to 5000mPa·s to 25000mPa·s, the positive electrode slurry is coated on the surface of the positive electrode collector, and after drying, the positive electrode sheet is formed by cold rolling; the positive electrode powder coating unit area density is 150mg / m 2 ~350 mg / m 2 The compaction density of the positive electrode is 3.0g / cm 3 ~3.6g / cm 3 , optional 3.3g / cm 3 ~3.5g / cm 3 .

[0118] The calculation formula of the compacted density is:

[0119] Compaction density = coating surface density / (thickness of the electrode after extrusion - thickness of the current collector).

[0120] The mass M of the positive electrode active material per unit area of ​​the positive electrode membrane can be obtained by weighing using a standard balance.

[0121] The thickness T of the positive electrode film can be measured using a micrometer, for example, a Mitutoyo 293-100 with an accuracy of 0.1 μm. It should be noted that the thickness of the positive electrode film described in this application refers to the thickness of the positive electrode film in the positive electrode sheet after cold pressing and used in battery assembly.

[0122] Negative electrode

[0123] The negative electrode sheet adopts the negative electrode sheet including lithium metal foil in this application.

[0124] electrolytes

[0125] The electrolyte conducts ions between the positive and negative electrodes. This application does not specifically limit the type of electrolyte, and the electrolyte can be selected based on the needs. For example, the electrolyte can be liquid, gel, or solid.

[0126] In some embodiments, the electrolyte is an electrolyte solution, which includes an electrolyte salt and a solvent.

[0127] In some embodiments, the electrolyte salt of the lithium ion battery may include one or more of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bisfluorosulfonyl imide (LiFSI), lithium bistrifluoromethanesulfonyl imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalatoborate (LiDFOB), lithium bisoxalatoborate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorobisoxalatophosphate (LiDFOP), and lithium tetrafluorooxalatophosphate (LiTFOP).

[0128] In some embodiments, the solvent may include fluoroethylene carbonate (FEC), ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butylene carbonate (BC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone ( EMS and diethyl sulfone (ESE), methyl ether (DME), ethyl ether (DEE), propyl ether (DPE), butyl ether (DBE), methyl ethyl ether (MEE), methyl propyl ether (MPE), methyl butyl ether (MBE), ethyl propyl ether (EPE), ethyl butyl ether (EBE), propyl butyl ether (PBE), dimethoxymethane (DMM), diethoxymethane (DEM), dipropoxymethane (DPM), dimethoxyethane (DME), dimethoxypropane (DMP), diethoxyethane (DEE), ethylene glycol methyl ethyl ether (EGEME), diethylene glycol dimethyl ether (DEGDME), triethylene glycol dimethyl ether (TEGDME), tetraethylene glycol dimethyl ether (TEGDME), tetrahydrofuran (THF), 1,3-dioxolane (DOL), tetrahydropyran (THP), 1,3-dioxane (1,3-DX), 1,4-dioxane (1,4-DX), fluorobenzene, p-difluorobenzene, m-difluorobenzene, o-difluorobenzene, trifluorotoluene, trifluoromethoxybenzene, decafluoropentane, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 1,2-dimethoxy-1,1,2,2-tetrafluoroethane, 1,2-bis(difluoromethoxy)ethane, 1,2-bis(trifluoromethoxy)ethane, 1,2-diethoxy-1,1,2,2-tetrafluoroethane, 1,2-bis(1,1,2,2-tetrafluoroethoxy)ethane, bis(2,2,2-trifluoroethyl)ether, bis( 2,2-difluoroethyl) ether, 1,1,2,3,3,3-hexafluoropropyl ethyl ether, 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether, ethyl trifluoromethyl ether, difluoromethyl-2,2,3,3,3-pentafluoropropyl ether, heptafluoropropyl-1,2,2,2-tetrafluoroethyl ether, difluoromethyl 2,2,3,3-tetrafluoropropyl ether, perfluoroisopropyl methyl ether, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, ethyl-1,1,2,2-tetrafluoroethyl ether, ethyl-2,2,2-tetrafluoroethyl ether, bis(1,1,2,2-tetrafluoroethyl) ether, N,N-dimethylfluorosulfonamide, N,N-dimethyltrifluoromethanesulfonamide or one or more thereof.

[0129] In some embodiments, the electrolyte may optionally include additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery properties, such as additives that improve battery overcharge performance, and additives that improve battery high or low temperature performance.

[0130] In some embodiments, the additives in the electrolyte may include, but are not limited to, one or more of fluoroethylene carbonate (FEC), difluoroethylene carbonate (DFEC), trifluoromethylethylene carbonate (TFPC), and the like.

[0131] Isolation film

[0132] In some embodiments, the battery further includes a separator. The present application has no particular limitation on the type of separator, and any known porous separator with good chemical and mechanical stability can be selected.

[0133] In some embodiments, the material of the separator can include one or more of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation.

[0134] In some embodiments, the isolation film has a thickness of 6 μm to 40 μm, and may optionally be 12 μm to 20 μm.

[0135] In some embodiments, the positive electrode sheet, the negative electrode sheet, and the separator can be formed into an electrode assembly through a winding process or a lamination process.

[0136] In some embodiments, the battery may include an outer packaging that can be used to encapsulate the electrode assembly and the electrolyte.

[0137] In some embodiments, the outer packaging of the battery can be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. The outer packaging of the battery can also be a soft shell, such as a pouch-type soft shell. The material of the soft shell can be plastic. Further, non-limiting examples of plastic can include one or more of polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0138] A battery includes at least one battery cell. A battery may include one or more battery cells.

[0139] In this application, unless otherwise specified, a "battery cell" refers to a basic unit that can achieve the mutual conversion of chemical energy and electrical energy. Further, generally speaking, it includes at least a positive electrode plate, a negative electrode plate, and an electrolyte. During the battery's charge and discharge process, active ions are embedded in and out of the positive and negative electrode plates. The electrolyte plays the role of conducting active ions between the positive and negative electrode plates.

[0140] The present application has no particular limitation on the shape of the battery cell, which can be cylindrical, square, or any other shape. For example, FIG14 shows a battery cell 5 with a square structure as an example.

[0141] In some embodiments, referring to Figure 15, the outer packaging may include a shell 51 and a cover plate 53. The shell 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a receiving cavity. The shell 51 has an opening connected to the receiving cavity, and the cover plate 53 can be covered on the opening to close the receiving cavity. The positive electrode sheet, the negative electrode sheet and the isolation membrane can be formed into an electrode assembly 52 through a winding process or a lamination process. The electrode assembly 52 is encapsulated in the receiving cavity. The electrolyte is infiltrated in the electrode assembly 52. ​​The number of electrode assemblies 52 contained in the battery cell 5 can be one or more, and those skilled in the art can select according to specific actual needs.

[0142] In some embodiments, the battery cells 5 can be assembled into a battery module. The number of battery cells 5 contained in the battery module can be one or more. The specific number can be selected by those skilled in the art according to the application and capacity of the battery module.

[0143] In the battery module, the plurality of battery cells 5 can be arranged in sequence along the length of the battery module. Of course, they can also be arranged in any other manner. Furthermore, the plurality of battery cells 5 can be fixed by fasteners.

[0144] Optionally, the battery module may further include a housing having an accommodation space, and the plurality of battery cells 5 are accommodated in the accommodation space.

[0145] In some embodiments, the battery modules described above may also be assembled into a battery pack. The battery pack may contain one or more battery modules, and the specific number may be selected by those skilled in the art based on the application and capacity of the battery pack.

[0146] A battery pack may include a battery box and multiple battery modules disposed within the box. The battery box comprises an upper case and a lower case. The upper case can be placed over the lower case to form an enclosed space for accommodating the battery modules. The multiple battery modules can be arranged in any manner within the battery box.

[0147] In addition, the present application also provides an electrical device, which includes at least one of the batteries, battery modules, or battery packs provided in the present application. The battery, battery module, or battery pack can be used as a power source for the electrical device, and can also be used as an energy storage unit for the electrical device. The electrical device may include 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 and satellites, energy storage systems, etc., but is not limited thereto.

[0148] As the electrical device, a battery, a battery module or a battery pack can be selected according to its usage requirements.

[0149] Figure 16 shows an example of an electric device 6. The electric device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the electric device's requirements for high power and high energy density, a battery pack or battery module can be used.

[0150] Another example device may be a mobile phone, a tablet computer, a laptop computer, etc. Such a device is usually required to be light and thin, and may use a battery as a power source.

[0151] The following are some examples.

[0152] In order to make the technical problems, technical solutions and beneficial effects solved by this application clearer, the application will be further described in detail below with reference to the embodiments and drawings. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present application and its applications. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0153] If no specific techniques or conditions are specified in the examples, the experiments were carried out according to the techniques or conditions described in the literature in the field or according to the product instructions. All reagents or instruments used without specifying the manufacturer are commercially available conventional products.

[0154] 1. Implementation

[0155] Example 1:

[0156] 1) Preparation of positive electrode sheet

[0157] The positive electrode active material NCM 811A positive electrode slurry is prepared by stirring and dispersing the conductive agent Ketjen Black and the binder polyvinylidene fluoride in N-methylpyrrolidone (NMP) in a mass ratio of 98:1:1. This slurry is then coated on a 7μm-thick aluminum foil serving as the positive electrode current collector. After compaction using a cold press, an active material layer is formed on the positive electrode current collector. A mixed slurry of polyvinylidene fluoride and alumina particles is then coated on the positive electrode current collector. The mass ratio of polyvinylidene fluoride to alumina particles is 1:9, and the mixed slurry is placed around the active material layer. After curing, an inactive material layer is formed around the active material layer to form a positive electrode sheet. The thickness of the inactive material layer is equal to that of the active material layer.

[0158] 2) Preparation of negative electrode sheet

[0159] Two lithium metal foils are stacked, with copper foil sandwiched between one end of the two lithium metal foils. One end of the copper foil extends from the end of the lithium metal foil to form a blank area. Rolling is performed under heating conditions to laminate the two lithium metal foils and the copper foil together. The area of ​​the lithium metal foil covered with copper foil forms the tab lead-out portion, and the area not covered with copper foil forms the electrode sheet. The blank area of ​​the copper foil is trimmed to form the tab connecting piece, thereby obtaining the negative electrode sheet. The thickness of the laminated lithium metal foil is 30μm, and the length of the copper foil within the tab lead-out portion is equal to the width of the lithium metal foil.

[0160] 3) Electrolyte preparation

[0161] Lithium salt LiPF6 was added to a mixed solvent of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) in a mass ratio of 35:65, and the mixture was mixed to obtain an electrolyte solution. The molar concentration of LiPF6 in the electrolyte solution was 1 mol / L.

[0162] 4) Isolation film

[0163] A 12 μm thick polyethylene porous membrane was selected as the separator.

[0164] 5) Preparation of lithium metal batteries

[0165] The positive electrode sheet, separator, and negative electrode sheet prepared above are stacked in order, with the separator placed between the positive electrode sheet and the negative electrode sheet to act as an insulator, and then wound to obtain a bare battery cell; a schematic diagram of the stacking of the positive electrode sheet and the negative electrode sheet is shown in FIG7 ;

[0166] The orthographic projection of the active material layer of the positive electrode sheet on the negative electrode sheet is located within the range of the electrode portion of the negative electrode sheet; the orthographic projection of the edge of the electrode portion of the negative electrode sheet on the positive electrode sheet is located within the range of the inactive material layer; the orthographic projection of the outer edge of the tab lead-out portion on the positive electrode sheet is located within the range of the inactive material layer; the spacing a between the orthographic projection of the edge of the electrode portion on the positive electrode sheet and the outer edge of the inactive material layer is 1.5 mm; the spacing b between the orthographic projection of the edge of the electrode portion on the positive electrode sheet and the outer edge of the active material layer is 1.5 mm;

[0167] The bare cell is inserted into the battery case and a lithium metal battery is obtained through the following processes: baking, electrolyte injection, resting, packaging, formation, and capacity division. The electrolyte injection coefficient is 1.5g / Ah.

[0168] Example 2:

[0169] This embodiment is essentially the same as Example 1, differing only in that a composite current collector is used for the positive electrode. The positive electrode current collector comprises a polyimide polymer support layer, with aluminum metal deposited on both the upper and lower surfaces as a conductive layer. Both the active material layer and the inactive material layer are disposed on the conductive layer. The polymer support layer is 3 μm thick, and the conductive layer is 2 μm thick. A schematic diagram of the positive electrode sheet structure in this embodiment is shown in Figure 2 , and a schematic diagram of the positive electrode current collector structure is shown in Figure 5 .

[0170] Example 3:

[0171] This embodiment is essentially the same as Example 2, differing only in that the thickness of the inactive material layer is designed to be gradual; extending outward from the side of the inactive material layer closest to the active material layer, the thickness of the inactive material layer gradually decreases from equal to the thickness of the active material layer to zero. A schematic diagram of the structure of the positive electrode sheet in this embodiment is shown in Figure 3.

[0172] Example 4:

[0173] This embodiment is essentially the same as Example 2, differing only in that the thickness of the inactive material layer is designed in regions; the inactive material layer comprises a first region and a second region, the first region being adjacent to the active material layer and the second region being located on the side of the first region facing away from the active material layer. The thickness of the inactive material layer within the first region is equal to the thickness of the active material layer; the width of the first region is equal to the distance b between the orthographic projection of the electrode edge on the positive electrode sheet and the outer edge of the active material layer, which is 1.5 mm; and the thickness of the inactive material layer within the second region gradually decreases from equal to the thickness of the active material layer to zero, extending outward from the side adjacent to the first region. A schematic structural diagram of the positive electrode sheet in this embodiment is shown in Figure 4.

[0174] Example 5:

[0175] This embodiment is basically the same as Example 2, with the only difference being that: the distance a between the orthographic projection of the edge of the electrode portion in the bare cell on the positive electrode sheet and the outer edge of the inactive material layer is 1 mm; the distance b between the orthographic projection of the edge of the electrode portion on the positive electrode sheet and the outer edge of the active material layer is 1 mm.

[0176] Example 6:

[0177] This embodiment is basically the same as Example 2, with the only difference being that: the distance a between the orthographic projection of the edge of the electrode portion in the bare cell on the positive electrode sheet and the outer edge of the inactive material layer is 3 mm; the distance b between the orthographic projection of the edge of the electrode portion on the positive electrode sheet and the outer edge of the active material layer is 3 mm.

[0178] Example 7:

[0179] This embodiment is basically the same as Example 2, with the only difference being that: the distance a between the orthographic projection of the edge of the electrode portion in the bare cell on the positive electrode sheet and the outer edge of the inactive material layer is 5 mm; the distance b between the orthographic projection of the edge of the electrode portion on the positive electrode sheet and the outer edge of the active material layer is 5 mm.

[0180] Example 8:

[0181] This embodiment is essentially the same as Example 7, differing only in that the orthographic projection of the outer edge of the tab extension onto the positive electrode sheet lies outside the inactive material layer, meaning the inactive material layer does not cover the outer edge of the tab extension. A schematic diagram of the stacked positive and negative electrode sheets in the battery of this embodiment is shown in Figure 6.

[0182] Example 9:

[0183] This embodiment is basically the same as embodiment 2, with the only difference being that the material of the inactive material layer in the positive electrode plate is different; in this embodiment, the inactive material layer is a mixture of polyvinylidene fluoride-hexafluoropropylene copolymer and titanium oxide particles.

[0184] Example 10:

[0185] This embodiment is basically the same as embodiment 2, with the only difference being that the thickness of the negative electrode lithium metal foil is 10 μm.

[0186] Example 11:

[0187] This embodiment is basically the same as embodiment 2, with the only difference being that the thickness of the negative electrode lithium metal foil is 50 μm.

[0188] Example 12:

[0189] This embodiment is substantially the same as embodiment 2, with the only difference being that a copper foil with a thickness of 10 μm is used as the negative electrode current collector, and a lithium metal layer with a thickness of 15 μm is formed on each side of the copper foil.

[0190] 2. Comparative Example

[0191] Comparative Example 1:

[0192] This comparative example is basically the same as Example 2, with the only difference being that: an active material layer is provided on the entire conductive layer of the positive electrode sheet, and no inactive material layer is provided around the active material layer; and the orthographic projection of the active material layer of the positive electrode sheet on the negative electrode sheet is located within the range of the electrode portion of the negative electrode sheet; the edge of the electrode portion of the negative electrode sheet exceeds the range of the active material layer of the positive electrode sheet, that is, the electrode portion exceeds the active material layer of the positive electrode sheet in both the length and width directions of the electrode sheet, thereby forming an overhang area.

[0193] Comparative Example 2:

[0194] This comparative example is basically the same as Example 10, with the only difference being that: an active material layer is provided on the entire conductive layer of the positive electrode sheet, and no inactive material layer is provided around the active material layer; and the orthographic projection of the active material layer of the positive electrode sheet on the negative electrode sheet is located within the range of the electrode portion of the negative electrode sheet; the edge of the electrode portion of the negative electrode sheet exceeds the range of the active material layer of the positive electrode sheet, that is, the electrode portion exceeds the active material layer of the positive electrode sheet in both the length and width directions of the electrode sheet, thereby forming an overhang area.

[0195] 3. Performance Testing

[0196] 1) Calculation of battery energy density

[0197] The mass of the lithium metal cell prepared above was weighed and recorded as m. The ambient temperature was then set to 25°C, and a charge and discharge test was performed. The constant current-constant voltage charging process was used during the charging process. The constant current charging used a rate of 0.1C. After charging to 4.3V, the constant voltage charging mode was entered, and the cutoff current was set to 0.05C. After full charge, the cell was allowed to rest for 10 minutes, and then a constant current discharge test was performed using a rate of 0.1C, with the lower cutoff voltage set to 2.8V. After the discharge was terminated, the total discharge energy was recorded as E0. The cell energy density e can then be calculated using the following formula: e = E0 / m.

[0198] 2) Battery cycle life test

[0199] Take the battery cell with the energy density determined above, set the ambient temperature to 25°C, and perform charge and discharge cycles at a rate of 0.2C charging and 1C discharging. The cut-off voltages for charge and discharge are set to 4.3V and 2.8V, respectively, and the charging process adopts a constant current-constant voltage charging method. Specifically, after the 0.2C constant current charge reaches the cut-off voltage of 4.3V, it continues to use a constant voltage charging method of 4.3V until the current decays to 0.05C. When the discharge capacity decays to 80% of the first cycle discharge capacity, the battery life is considered to have expired, and the number of cycles at this time is the cycle life of the battery cell.

[0200] The parameters and performance test results of the lithium metal batteries of the above embodiments and comparative examples are shown in Table 1.

[0201] Table 1

[0202] From Table 1 we can see that:

[0203] The lithium metal batteries of the various embodiments of the present application have higher energy density and longer cycle life.

[0204] Comparing Example 1 with Example 2, it can be seen that using a composite current collector for the positive electrode can significantly improve the energy density of the battery while maintaining the cycle life.

[0205] By comparing Example 2 and Example 3, it can be seen that the inactive material layer of the positive electrode plate in Example 3 adopts a thickness gradient design (that is, the thickness of the inactive material layer gradually decreases from the same thickness as the active material layer to zero in the direction extending outward from the side of the inactive material layer close to the active material layer), which can further improve the energy density of the battery.

[0206] Comparing Examples 2 to 4, it can be seen that the thickness of the inactive material layer of the positive electrode sheet in Example 4 is divided into different regions. This ensures that the lithium in the overhang area of ​​the negative electrode is under pressure during the cycle, reducing the growth of lithium dendrites in this area while achieving maximum weight reduction. The lithium metal battery of Example 4 has high energy density and long cycle performance.

[0207] By comparing Example 2 with Examples 5 to 7, it can be seen that by controlling the widths of a and b within the range of 1 mm to 5 mm, the battery can have both a higher energy density and a longer cycle life; further, by controlling the widths of a and b within the range of 1.5 mm to 3 mm, the battery's energy density and cycle life can be better balanced.

[0208] Comparing Example 7 with Example 8, it can be seen that the inactive material layer in Example 7 covers the tab lead-out portion, which is beneficial to ensuring that the entire area of ​​the negative electrode lithium metal foil is under pressure, and is more conducive to extending the cycle life of the battery.

[0209] By comparing Example 2 with Examples 10 to 11, it can be seen that controlling the thickness of the negative electrode lithium metal foil within the range of 10 μm to 50 μm can make the battery have a high energy density and a long cycle life; further, controlling the thickness of the negative electrode lithium metal foil within the range of 30 μm to 50 μm can better balance the energy density and cycle life of the battery, thereby obtaining a battery with high energy density and long cycle life.

[0210] The negative electrode of the battery in Example 12 is made of 10 μm copper foil covered with a 15 μm lithium metal layer on both sides. Although the cycle life of the battery is good, its energy density is lower than that of Example 2.

[0211] Comparing Example 2 with Comparative Examples 1-2, it can be seen that when the positive electrode sheet of the lithium metal battery does not use the positive electrode sheet of the present application, the cycle life of the battery is significantly reduced. The batteries of Comparative Examples 1-2 cannot achieve both high energy density and long cycle life.

[0212] The above description of the various embodiments tends to emphasize the differences between the various embodiments. The same or similar aspects can be referenced with each other and will not be repeated herein for the sake of brevity.

[0213] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and within the scope of the technical solution of the present application, embodiments having substantially the same structure as the technical concept and exerting the same effects are all included in the technical scope of the present application. In addition, within the scope of the subject matter of the present application, various modifications that can be conceived by those skilled in the art to the embodiments, and other methods constructed by combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A positive electrode sheet, wherein: The invention comprises a positive electrode current collector and an active material layer and an inactive material layer arranged on at least one surface of the positive electrode current collector, wherein the inactive material layer is arranged around the periphery of the active material layer, the active material layer comprises a positive electrode active material, and the active material layer and the inactive material layer are arranged in the same layer.

2. The positive electrode sheet according to claim 1, wherein: The material of the inactive material layer includes an insulating material, and the insulating material includes one or more of an organic insulating material and an inorganic insulating material.

3. The positive electrode sheet according to claim 2, wherein: The organic insulating material includes an organic polymer, and the organic polymer includes one or more of polymethyl methacrylate, polyimide, polyethylene, polypropylene, polytetrafluoroethylene, polyvinylidene fluoride, and polyvinylidene fluoride-hexafluoropropylene copolymer.

4. The positive electrode sheet according to claim 2 or 3, wherein: The inorganic insulating material includes oxide particles, and the oxide particles include one or more of aluminum oxide particles and titanium oxide particles.

5. The positive electrode sheet according to any one of claims 1 to 4, wherein: The thickness of the inactive material layer is equal to the thickness of the active material layer.

6. The positive electrode sheet according to any one of claims 1 to 5, wherein: The thickness of the inactive material layer at a side close to the active material layer is greater than the thickness of the inactive material layer at a side far from the active material layer.

7. The positive electrode sheet according to any one of claims 1 to 6, wherein: The thickness of the inactive material layer gradually decreases in a direction extending outward from a side of the inactive material layer close to the active material layer.

8. The positive electrode sheet according to any one of claims 1 to 7, wherein: The inactive material layer includes a first region and a second region, the first region is close to the active material layer, the second region is located on the side of the first region away from the active material layer, the thickness of the inactive material layer in the first region is equal to the thickness of the active material layer; in a direction extending outward from the side close to the first region, the thickness of the inactive material layer in the second region gradually decreases.

9. The positive electrode sheet according to any one of claims 1 to 8, wherein: The positive electrode current collector comprises a polymer support layer and a conductive layer disposed on at least one surface of the polymer support layer, and the active material layer and the inactive material layer are disposed on a surface of the conductive layer away from the polymer support layer.

10. A battery, wherein: It comprises a positive electrode sheet and a negative electrode sheet which are stacked, the positive electrode sheet comprises the positive electrode sheet according to any one of claims 1 to 9, the negative electrode sheet comprises a lithium metal foil, the lithium metal foil comprises a pole piece portion and a tab lead-out portion connected to the pole piece portion, and the orthographic projection of the edge of the pole piece portion on the positive electrode sheet is located within the range of the inactive material layer.

11. The battery according to claim 10, wherein The distance between the orthographic projection of the edge of the pole piece on the positive pole piece and the outer edge of the inactive material layer is a, and a is 1 mm to 5 mm.

12. The battery according to claim 11, wherein a is 1.5mm~3mm.

13. The battery according to any one of claims 10 to 12, wherein The orthographic projection of the active material layer on the negative electrode sheet is located within the range of the electrode sheet portion.

14. The battery according to claim 13, wherein The distance between the orthographic projection of the edge of the electrode portion on the positive electrode sheet and the outer edge of the active material layer is b, and b is 1 mm to 5 mm.

15. The battery according to claim 14, wherein b is 1.5mm~3mm.

16. The battery according to claim 14 or 15, wherein: The inactive material layer includes a first region and a second region, the first region is close to the active material layer, and the second region is located on the side of the first region away from the active material layer; in a direction extending outward from the side close to the first region, the thickness of the inactive material layer in the second region gradually decreases; the thickness of the inactive material layer in the first region is equal to the thickness of the active material layer.

17. The battery according to any one of claims 10 to 16, wherein The orthographic projection of the outer edge of the tab lead-out portion on the positive electrode sheet is located within the range of the inactive material layer.

18. The battery according to any one of claims 10 to 17, wherein The tab lead-out portion is provided with a tab lead-out foil compounded with the lithium metal foil, and the tab lead-out foil is connected to a tab connecting piece.

19. The battery according to claim 18, wherein The width of the tab connecting piece is c, the length of the tab lead foil is d, the width of the lithium metal foil at one end close to the tab connecting piece is e, and c≤d≤e.

20. The battery according to any one of claims 10 to 19, wherein The thickness of the lithium metal foil is 10 μm to 50 μm.

21. The battery according to any one of claims 10 to 20, wherein The thickness of the lithium metal foil is 30 μm to 50 μm.

22. An electrical device, wherein: A battery comprising the battery according to any one of claims 10 to 21.

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