Composite foil, pole piece, battery and electrical device

Abstract

The present application discloses a composite foil, a pole piece, a battery and an electrical device, wherein the composite foil comprises: a first metal layer; a second metal layer, the second metal layer and the first metal layer are stacked; at least one of the first metal layer and the second metal layer is a rolled layer; at least two stacked layers of the same metal foil are used to form at least two layers of the rolled layer with the same number of layers as the at least two layers of the same metal foil after stacking and slitting. The present application can make the thickness of the current collector relatively thinner, which is not only conducive to reducing the weight of the current collector, but also conducive to reducing the amount of materials used in the manufacturing of the current collector, thereby helping to reduce costs.

Description

Technical Field

[0001] The present application relates to the technical field of battery manufacturing, and in particular to a composite foil, a pole piece, a battery and an electrical device. Background Art

[0002] Electrification is an important way to get rid of fossil energy dependence and achieve dual carbon goals, and batteries play a vital role in the development of electrification trends. Improving the energy density and power characteristics of batteries is an important direction for battery development. As for how to improve the energy density and power characteristics of batteries, it has been proven in the applications of lead-acid batteries and nickel-hydrogen batteries that this can be solved by stacking and connecting bipolar high-voltage batteries in series inside the battery.

[0003] Compared with lead-acid batteries and nickel-metal hydride batteries, lithium batteries have advantages such as higher energy density and longer life. Bipolar lithium batteries are also a development direction. Bipolar lithium batteries are composed of two unipolar electrodes and several stacked bipolar electrodes. The bipolar electrodes are composed of current collectors, positive electrodes and negative electrodes respectively arranged on both sides of the current collectors, and the current collectors usually include stacked positive current collectors and negative current collectors. The positive current collector is often aluminum foil, and the negative current collector is often copper foil.

[0004] However, since the thickness of the aluminum foil and the copper foil is relatively thick, the thickness of the entire current collector will be relatively thick, which will in turn make the weight of the entire current collector relatively heavy. Since the thicker thickness will increase the amount of manufacturing materials, the cost will also be relatively high. Utility Model Content

[0005] In view of the above-mentioned deficiencies in the related art, the present application provides a composite foil, an electrode, a battery and an electrical device to solve the problem in the related art that the current collector is relatively heavy and has a relatively high cost due to its relatively thick thickness.

[0006] In order to solve the above technical problems, in a first aspect, the present application provides a composite foil, which comprises:

[0007] A first metal layer;

[0008] a second metal layer, the second metal layer being stacked with the first metal layer;

[0009] At least one of the first metal layer and the second metal layer is a rolled layer;

[0010] The at least two stacked layers of the same metal foil are used to form at least two rolled layers having the same number of layers as the at least two layers of the same metal foil after stacking and slitting.

[0011] In a possible implementation manner of the first aspect, the first metal layer is the rolled layer, and the second metal layer is a plated layer.

[0012] In a possible implementation of the first aspect, the composite foil further includes:

[0013] An intermediate layer is provided between the first metal layer and the second metal layer, the second metal layer is plated on the intermediate layer, and the intermediate layer is used to enhance the adhesion between the first metal layer and the second metal layer.

[0014] In a possible implementation manner of the first aspect, the intermediate layer is plated on the first metal layer.

[0015] In a possible implementation manner of the first aspect, the thickness of the intermediate layer is 10 nm-1000 nm.

[0016] In a possible implementation of the first aspect, the thickness of the first metal layer is 4 μm-12 μm;

[0017] and / or,

[0018] The thickness of the second metal layer is 0.1 μm-5 μm.

[0019] In a second aspect, the present application further provides a pole piece, the pole piece comprising:

[0020] The composite foil material according to any one of the first aspects, wherein the composite foil material is a current collector;

[0021] A positive electrode layer, the positive electrode layer being stacked on the first metal layer in the current collector;

[0022] A negative electrode layer is stacked on the second metal layer in the current collector.

[0023] In a third aspect, the present application further provides a battery, comprising:

[0024] The pole piece described in any one of the second aspects.

[0025] In a possible implementation of the third aspect, the pole piece is stacked in a plurality; the pole piece further includes a first insulating edge sealing layer and a second insulating edge sealing layer, the first insulating edge sealing layer is arranged on the first metal layer and around the positive electrode layer, and the second insulating edge sealing layer is arranged on the second metal layer and around the negative electrode layer;

[0026] The first insulating edge sealing layer and the second insulating edge sealing layer arranged opposite to each other in two adjacent pole pieces are used to bond the two adjacent pole pieces.

[0027] In a fourth aspect, the present application further provides an electrical device, the electrical device comprising:

[0028] The battery according to any one of the third aspects.

[0029] Compared with the related art, this application has at least the following beneficial effects:

[0030] In the present application, the composite foil includes a first metal layer and a second metal layer arranged in a stacked manner, and at least one metal layer is a rolled layer. Since the at least two stacked layers of the same metal foil are used to form at least two rolled layers with the same number of layers as the at least two layers of the same metal foil after stacking and slitting, and since during the stacking process of the at least two layers of the same metal foil, each layer of the metal foil will be simultaneously subjected to the rolling pressure, the compression ratio is increased, and thus the deformation degree of each layer of the metal foil is greater, thereby being able to achieve a greater thickness reduction of the metal foil, that is, the thickness of the rolled layer is thinner than the thickness of a single-layer rolled or unstacked metal foil, that is, the thickness of the rolled layer is thinner than the thickness of the aluminum foil and copper foil that constitute the current collector in the related art.

[0031] According to the above description, in the present application, since at least one metal layer in the composite foil is a rolled layer thinner than the aluminum foil and copper foil constituting the current collector in the related art, the composite foil composed of two stacked metal layers is compared with the current collector composed of aluminum foil and copper foil stacked in the related art. The thickness of the composite foil is thinner than the thickness of the current collector in the related art. In this way, when the composite foil in the present application is used as the current collector, the thickness of the current collector can also become relatively thinner, which is not only beneficial to reduce the weight of the current collector, but also beneficial to reduce the amount of materials used in the manufacturing of the current collector, thereby helping to reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 A schematic diagram of a composite foil provided in an embodiment of the present application;

[0034] Figure 2 A cross-sectional view of a pole piece provided in an embodiment of the present application;

[0035] Figure 3 A top view of a pole piece provided in an embodiment of the present application;

[0036] Figure 4 An exploded view of a battery provided in an embodiment of the present application;

[0037] Figure 5 A schematic diagram of an electrical device provided in an embodiment of the present application;

[0038] Figure 6 A flow chart of a composite foil preparation method provided in an embodiment of the present application;

[0039] Figure 7 A schematic diagram of the process for preparing a composite foil provided in an embodiment of the present application.

[0040] Description of reference numerals:

[0041] 1-first metal layer;

[0042] 2- second metal layer;

[0043] 3- first metal foil;

[0044] 4-Viscosity reducing medium;

[0045] 10-composite foil;

[0046] 20- positive electrode layer;

[0047] 30- negative electrode layer;

[0048] 40-first insulating edge sealing layer;

[0049] 50- second insulating edge sealing layer;

[0050] 100-pole piece;

[0051] 200-diaphragm;

[0052] 300-single-sided positive electrode; 3001-single-sided positive electrode current collector; 3002-single-sided positive electrode layer; 3003-single-sided positive electrode insulating edge sealing layer;

[0053] 400-single-sided negative electrode; 4001-single-sided negative electrode current collector; 4002-single-sided negative electrode layer; 4003-single-sided negative electrode insulating edge sealing layer;

[0054] 1000-battery. DETAILED DESCRIPTION

[0055] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0056] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0057] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0058] In addition, the terms "installed", "set", "provided with", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0059] In addition, the terms "first", "second", etc. are mainly used to distinguish different devices, elements or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance and quantity of the indicated devices, elements or components. Unless otherwise specified, "plurality" means two or more.

[0060] As described in the background technology of this application, in the relevant technology, electrification is an important way to get rid of fossil energy dependence and achieve dual carbon goals, and batteries play a vital role in the development of electrification trends. Improving the energy density and power characteristics of batteries is an important direction for battery development. As for how to improve the energy density and power characteristics of batteries, it has been proven in the applications of lead-acid batteries and nickel-hydrogen batteries that this can be solved by preparing bipolar high-voltage batteries by stacking and connecting them in series inside the battery.

[0061] Compared with lead-acid batteries and nickel-metal hydride batteries, lithium batteries have advantages such as higher energy density and longer life. Bipolar lithium batteries are also a development direction. Bipolar lithium batteries are composed of two unipolar electrodes and several stacked bipolar electrodes. The bipolar electrodes are composed of current collectors, positive electrodes and negative electrodes respectively arranged on both sides of the current collectors, and the current collectors usually include stacked positive current collectors and negative current collectors. The positive current collector is often aluminum foil, and the negative current collector is often copper foil.

[0062] However, since the thickness of the aluminum foil and the copper foil is relatively thick, the thickness of the entire current collector will be relatively thick, which will in turn make the weight of the entire current collector relatively heavy. Since the thicker thickness will increase the amount of manufacturing materials, the cost will also be relatively high.

[0063] In view of the above-mentioned problems, the present application provides a composite foil material to solve the problem in the related art that the current collector is relatively heavy and has a relatively high cost due to the relatively thick thickness of the current collector.

[0064] The technical solution of the present application will be further described below in conjunction with specific embodiments and drawings:

[0065] like Figure 1 As shown, the composite foil 10 includes a first metal layer 1 and a second metal layer 2, the second metal layer 2 and the first metal layer 1 are stacked, and at least one of the first metal layer 1 and the second metal layer 2 is a rolled layer.

[0066] The at least two stacked layers of the same metal foil are used to form at least two rolled layers having the same number of layers as the at least two layers of the same metal foil after stacking and slitting.

[0067] In the present application, the composite foil 10 includes a first metal layer 1 and a second metal layer 2 arranged in a stacked manner, and at least one metal layer is a rolled layer. Since the at least two stacked layers of the same metal foil are used to form at least two rolled layers with the same number of layers as the at least two layers of the same metal foil after stacking and slitting, and since during the stacking process of the at least two layers of the same metal foil, each layer of the metal foil will be simultaneously subjected to the rolling pressure, the compression ratio is increased, and thus the deformation degree of each layer of the metal foil is greater, thereby being able to achieve a greater thickness reduction of the metal foil, that is, the thickness of the rolled layer is thinner than the thickness of a single-layer rolled or unstacked metal foil, that is, the thickness of the rolled layer is thinner than the thickness of the aluminum foil and copper foil that constitute the current collector in the related art.

[0068] According to the above description, in the present application, since at least one metal layer in the composite foil 10 is a rolled layer thinner than the aluminum foil and copper foil constituting the current collector in the related art, the composite foil 10 composed of two stacked metal layers is compared with the current collector composed of aluminum foil and copper foil stacked in the related art. The thickness of the composite foil 10 is thinner than the thickness of the current collector in the related art. In this way, when the composite foil 10 in the present application is used as a current collector, the thickness of the current collector can also become relatively thinner, which is not only beneficial to reduce the weight of the current collector, but also beneficial to reduce the amount of materials used in the manufacturing of the current collector, thereby helping to reduce costs.

[0069] As for the material of the first metal layer 1, in the embodiment of the present application, the material of the first metal layer 1 is aluminum or aluminum alloy. Since aluminum or aluminum alloy has the characteristics of light weight and good conductivity, using aluminum or aluminum alloy as the first metal layer 1 is not only conducive to reducing the weight of the composite foil 10, but also enables the composite foil 10 to have good conductivity.

[0070] As for the material of the second metal layer 2, in a preferred embodiment, the material of the second metal layer 2 is copper or a copper alloy. Since copper or a copper alloy has the characteristics of good conductivity and stability, using copper or a copper alloy as the second metal layer 2 can not only make the composite foil 10 have good conductivity, but also enhance the stability of the composite foil 10 to a certain extent, so that the composite foil 10 is relatively stable in some electrochemical environments, and is not prone to chemical reactions or structural changes, which helps to extend the life.

[0071] In other embodiments, the viscosity reducing medium 4 may also be mineral oil, animal or plant oil or emulsion, etc. The type of the viscosity reducing medium 4 can be flexibly selected. Specifically, it can be selected according to actual usage requirements, and the embodiments of the present application will not be elaborated on this.

[0072] Furthermore, the first metal layer 1 is a rolled layer, and the second metal layer 2 is a plated layer.

[0073] During the plating process, metal ions will be reduced and gradually deposited on the surface of the substrate to form a thin film as a plating layer, so that the thickness of the plating layer can be controlled, and the thickness of the plating layer can be made thinner than the rolled layer. In this way, on the basis of the first metal layer 1 as the rolled layer, the second metal layer 2 as the plating layer can be used to further make the thickness of the composite foil 10 thinner.

[0074] In other embodiments, one of the first metal layer 1 and the second metal layer 2 is a rolled layer, and the other is an unlaminated metal foil. In this way, for the metal layer composed of the unlaminated metal foil, the manufacturing process of the metal layer can be simplified, which is conducive to simplifying the manufacturing process of the composite foil 10.

[0075] As for the plating method of the second metal layer 2, in a preferred embodiment, the second metal layer 2 is formed by chemical plating and electroplating. Chemical plating and electroplating can complement each other. First, a uniform second metal layer 2 can be formed by chemical plating, and then the hardness of the second metal layer 2 can be further increased by electroplating, thereby improving the wear resistance, corrosion resistance and conductivity of the second metal layer 2.

[0076] In other embodiments, the second metal layer 2 is formed by chemical plating or electroplating, so that the plating process of the second metal layer 2 can be simplified, thereby facilitating improving work efficiency and reducing costs.

[0077] Furthermore, in a preferred embodiment, the composite foil 10 also includes an intermediate layer (not shown in the figure), the intermediate layer is arranged between the first metal layer 1 and the second metal layer 2, and the second metal layer 2 is plated on the intermediate layer, and the intermediate layer is used to enhance the adhesion between the first metal layer 1 and the second metal layer 2.

[0078] An intermediate layer is arranged between the first metal layer 1 and the second metal layer 2, and the intermediate layer can form a chemical bond with the first metal layer 1 and the second metal layer 2, so as to increase the bonding strength between the first metal layer 1 and the second metal layer 2, that is, the adhesion between the first metal layer 1 and the second metal layer 2 can be enhanced by the intermediate layer, which is beneficial to avoid the first metal layer 1 and the second metal layer 2 from falling off, and further beneficial to ensuring the manufacturing quality of the composite foil 10.

[0079] As for the material of the middle layer, in the embodiment of the present application, the material of the middle layer can be one or more of metals such as tin, nickel, zinc, silver and their related alloys. The material selection of the middle layer is relatively flexible, and can be selected according to actual use requirements, and the embodiment of the present application will not be elaborated in detail.

[0080] Furthermore, in a preferred embodiment, the intermediate layer is plated on the first metal layer 1 .

[0081] With such arrangement, the intermediate layer can be formed by the thin film plated on the first metal layer 1 , which can make the intermediate layer thinner and further reduce the influence of the intermediate layer on the overall thickness of the composite foil 10 .

[0082] As for the plating method of the intermediate layer, in a preferred embodiment, the intermediate layer is plated on the first metal layer 1 by electroplating and chemical plating. Chemical plating can form a chemical bond on the surface of the first metal layer 1 to increase the adhesion between the first metal layer 1 and the intermediate layer, and electroplating can further strengthen the adhesion, so that the intermediate layer is more firmly attached to the first metal layer 1, thereby improving the durability of the intermediate layer.

[0083] In other embodiments, the intermediate layer may be plated onto the first metal layer 1 by chemical plating or electroplating, which can simplify the plating process of the intermediate layer, thereby facilitating improving work efficiency and reducing costs.

[0084] Regarding the arrangement of the intermediate layer on the first metal layer 1, in other embodiments, the intermediate layer can also be arranged on the first metal layer 1 by physical vapor deposition, chemical vapor deposition or thermal spraying. The arrangement of the intermediate layer on the first metal layer 1 is relatively flexible, and can be selected according to actual use requirements, and the embodiments of the present application will not be elaborated on this.

[0085] Furthermore, the thickness of the intermediate layer is 10nm-1000nm.

[0086] With such a configuration, firstly, the intermediate layer can provide better adhesion, making the subsequent plating of the second metal layer 2 easier to implement, and can improve its adhesion and stability; secondly, the intermediate layer can absorb and disperse the stress generated during the processing or use of the composite foil 10, reduce the formation and expansion of cracks, improve the reliability of the composite foil 10, and more importantly, avoid affecting the overall thickness of the composite foil 10.

[0087] In the embodiment of the present application, the thickness of the intermediate layer can be 10 nm, 50 nm or 1000 nm. The thickness of the intermediate layer can be set flexibly. Specifically, it can be determined according to actual usage requirements. The embodiment of the present application will not be elaborated in detail.

[0088] In other embodiments, the thickness of the intermediate layer is less than 10 nm or greater than 1000 nm, for example, the thickness of the intermediate layer is 9 nm or 1005 nm, etc. This configuration facilitates the thickness setting of the intermediate layer.

[0089] As for the thickness of the first metal layer 1 and the second metal layer 2 , the thickness of the first metal layer 1 is 4 μm-12 μm; and / or the thickness of the second metal layer 2 is 0.1 μm-5 μm.

[0090] The thickness of the first metal layer 1 is set to 4 μm-12 μm, which not only ensures that the first metal layer 1 has a thinner thickness, but also the first metal layer 1 within this thickness range can still provide certain strength and toughness, which is conducive to facilitating subsequent reprocessing.

[0091] The thickness of the second metal layer 2 is set to 0.1 μm-5 μm, which can not only ensure that the second metal layer 2 has a relatively thinner thickness, but also the thinner thickness can reduce the plating time to a certain extent, which is conducive to facilitating the plating of the second metal layer 2 .

[0092] Furthermore, the thickness of the first metal layer 1 is 4 μm-12 μm, and the thickness of the second metal layer 2 is 0.1 μm-5 μm. Such a configuration is conducive to further making the composite foil 10 relatively thinner, which is not only conducive to further reducing the weight of the current collector, but also conducive to further reducing the amount of current collector manufacturing materials, which is conducive to further reducing costs.

[0093] In the embodiment of the present application, the thickness of the first metal layer 1 can be 4 μm, 8 μm or 12 μm, etc.; the thickness of the second metal layer 2 can be 0.1 μm, 3 μm or 5 μm, etc. The thickness of the first metal layer 1 and the second metal layer 2 can be set flexibly, and can be determined according to actual use requirements, which will not be elaborated in detail in the embodiment of the present application.

[0094] In other embodiments, the thickness of the first metal layer 1 is less than 4 μm or greater than 12 μm, such as 3 μm or 13 μm, etc.; the thickness of the second metal layer 2 is less than 0.1 μm or greater than 5 μm, such as 0.09 μm or 6 μm, etc. Such a configuration facilitates the thickness setting of the first metal layer 1 and the second metal layer 2.

[0095] The present application also provides a pole piece 100, such as Figure 2 and Figure 3 As shown, the electrode sheet 100 includes a composite foil 10, a positive electrode layer 20 and a negative electrode layer 30, wherein the composite foil 10 is a current collector, and the composite foil 10 has the same structure as any of the composite foils 10 in the above embodiments, and can bring the same or similar beneficial effects. For details, please refer to the description in the above embodiments, which will not be repeated in this embodiment.

[0096] The positive electrode layer 20 is stacked on the first metal layer 1 in the current collector, and the negative electrode layer 30 is stacked on the second metal layer 2 in the current collector.

[0097] In the present application, since at least one metal layer in the composite foil 10 is a rolled layer thinner than the aluminum foil and copper foil constituting the current collector in the related art, the composite foil 10 composed of two stacked metal layers is thinner than the current collector composed of aluminum foil and copper foil stacked in the related art. In this way, when the composite foil 10 in the present application is used as a current collector, the thickness of the current collector can also become relatively thinner, which is not only beneficial to reduce the weight of the current collector, but also beneficial to reduce the amount of materials used in the manufacturing of the current collector, thereby helping to reduce costs.

[0098] For the positive electrode layer 20, the positive electrode layer 20 contains positive electrode active materials, conductive agents, adhesives, and may also include solid electrolytes. Among them, the positive electrode active materials may include common lithium-ion battery positive electrode materials, such as lithium cobalt oxide, lithium manganese oxide, nickel cobalt manganese oxide, lithium iron phosphate, sulfur-carbon composite materials, lithium sulfide, etc. The material selection of the positive electrode layer 20 is relatively flexible, and specifically, it can be selected according to actual use requirements, and the embodiments of the present application will not be elaborated in detail.

[0099] For the negative electrode layer 30, the negative electrode layer 30 contains negative electrode active materials, conductive agents, adhesives, and may also include solid electrolytes. Among them, the negative electrode active materials may include common lithium-ion battery negative electrode materials, such as natural graphite, artificial graphite, mesophase carbon microspheres, soft carbon, hard carbon, composite silicon oxygen materials, composite silicon carbon materials, lithium titanate, metallic lithium and its composites, lithium alloys, and metal materials that can form lithium alloys. The material selection of the negative electrode layer 30 is relatively flexible. Specifically, it can be selected according to actual use requirements, and the embodiments of the present application will not be elaborated in detail.

[0100] In addition, if Figure 2 As shown, the length and width of the positive electrode layer 20 are smaller than those of the negative electrode layer 30. First, the negative electrode layer 30 usually needs to provide more capacity to store charge, because during the battery charging process, the corresponding charge ions will migrate from the positive electrode layer 20 to the negative electrode layer 30, so in order to provide sufficient storage space, the size of the negative electrode layer 30 will be designed to be larger. Secondly, the positive electrode layer 20 and the negative electrode layer 30 play different roles in the battery reaction. The positive electrode layer 20 is usually an oxidant, while the negative electrode layer 30 is a reductant. In some battery designs, a larger area of ​​the negative electrode layer 30 is required to promote the chemical reaction.

[0101] The present application also provides a battery 1000, such as Figure 4 As shown, the battery 1000 includes a pole piece 100, which has the same structure as any pole piece 100 in the above embodiments and can bring the same or similar beneficial effects. For details, please refer to the description in the above embodiments, which will not be repeated in this embodiment.

[0102] In the present application, since at least one metal layer in the composite foil 10 is a rolled layer thinner than the aluminum foil and copper foil constituting the current collector in the related art, the composite foil 10 composed of two stacked metal layers is thinner than the current collector composed of aluminum foil and copper foil stacked in the related art. In this way, when the composite foil 10 in the present application is used as a current collector, the thickness of the current collector can also become relatively thinner, which is not only beneficial to reduce the weight of the current collector, but also beneficial to reduce the amount of materials used in the manufacturing of the current collector, thereby helping to reduce costs.

[0103] Furthermore, if Figure 4 As shown, the pole piece 100 is stacked in a plurality of layers, such as Figure 2 , Figure 3 and Figure 4 As shown, the pole piece 100 also includes a first insulating edge sealing layer 40 and a second insulating edge sealing layer 50. The first insulating edge sealing layer 40 is arranged on the first metal layer 1 and around the positive electrode layer 20. The second insulating edge sealing layer 50 is arranged on the second metal layer 2 and around the negative electrode layer 30.

[0104] like Figure 4 As shown, the first insulating edge sealing layer 40 and the second insulating edge sealing layer 50 arranged opposite to each other in two adjacent pole pieces 100 are used to bond the two adjacent pole pieces 100 together.

[0105] With such an arrangement, firstly, the first insulating edge sealing layer 40 and the second insulating edge sealing layer 50 can prevent the positive electrode layer 20 and the negative electrode layer 30 from direct contact, thereby avoiding a short circuit inside the battery 1000; secondly, if the battery 1000 contains an electrolyte, the first insulating edge sealing layer 40 and the second insulating edge sealing layer 50 can effectively isolate the electrolyte, thereby avoiding the electrolyte from penetrating between the positive electrode layer 20 and the negative electrode layer 30, thereby causing a short circuit or other adverse reactions; finally, by bonding two adjacent pole pieces 100 together through the relatively arranged first insulating edge sealing layer 40 and the second insulating edge sealing layer 50, the structural stability of the battery 1000 can be enhanced.

[0106] In a preferred embodiment, Figure 4 As shown, the battery 1000 also includes a diaphragm 200, a positive electrode single surface 300 and a negative electrode single surface 400. In the direction in which each electrode sheet 100 is stacked, the positive electrode single surface 300 and the negative electrode single surface 400 are respectively arranged on both sides of each electrode sheet 100. There are multiple diaphragms 200. The diaphragm 200 is not only arranged between the positive electrode single surface 300 and the electrode sheet 100 adjacent to the positive electrode single surface 300, between the negative electrode single surface 400 and the electrode sheet 100 adjacent to the negative electrode single surface 400, but also arranged between two adjacent electrode sheets 100, and the first insulating edge sealing layer 40 and the second insulating edge sealing layer 50 arranged oppositely in the two adjacent electrode sheets 100 bond the two adjacent electrode sheets 100 through the diaphragm 200.

[0107] like Figure 4 As shown, the single-sided positive electrode 300 includes a single-sided positive electrode current collector 3001, a single-sided positive electrode layer 3002 stacked on the single-sided positive electrode current collector 3001, and a single-sided positive electrode insulating edge sealing layer 3003 arranged around the single-sided positive electrode layer 3002. The single-sided positive electrode layer 3002 can be aluminum or aluminum alloy foil.

[0108] like Figure 4 As shown, the negative electrode single side 400 includes a single-sided negative electrode current collector 4001, a single-sided negative electrode layer 4002 stacked on the single-sided negative electrode current collector 4001, and a single-sided negative electrode insulating edge sealing layer 4003 arranged around the single-sided negative electrode layer 4002. The single-sided negative electrode layer 4002 can be copper or copper alloy foil.

[0109] like Figure 4 As shown, the positive electrode single side 300, each electrode sheet 100, each separator 200 and the negative electrode single side 400 are stacked and pressed to form a battery cell. The battery 1000 also includes a positive electrode handle, a negative electrode handle and a shell (not shown). The positive electrode single side 300 and the negative electrode single side 400 are respectively connected to the positive electrode handle and the negative electrode handle and thus connected to the external circuit. The battery cell is encapsulated in the shell.

[0110] In addition, it should be noted that the battery 1000 can be a fully solid-state battery or a liquid battery containing an electrolyte. When the battery 1000 is a bipolar lithium battery, each positive and negative electrode sheet forms a series connection structure, and the single cell can achieve a higher voltage, which is conducive to improving energy density and power density.

[0111] The present application also provides an electrical device, such as Figure 5 As shown, the battery power device includes a battery 1000, which has the same structure as any of the batteries 1000 in the above embodiments and can bring the same or similar beneficial effects. For details, please refer to the description in the above embodiments, which will not be repeated in this embodiment.

[0112] In the present application, since at least one metal layer in the composite foil 10 is a rolled layer thinner than the aluminum foil and copper foil constituting the current collector in the related art, the composite foil 10 composed of two stacked metal layers is thinner than the current collector composed of aluminum foil and copper foil stacked in the related art. In this way, when the composite foil 10 in the present application is used as a current collector, the thickness of the current collector can also become relatively thinner, which is not only beneficial to reduce the weight of the current collector, but also beneficial to reduce the amount of materials used in the manufacturing of the current collector, thereby helping to reduce costs.

[0113] With respect to the electrical device, the electrical device may be any type of electrical device, and the embodiments of the present application do not specifically limit this. In the embodiments of the present application, the electrical device is described by taking a vehicle as an example.

[0114] The vehicle can be a fuel vehicle, a gas vehicle or a new energy vehicle, wherein the new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 1000 is arranged inside the vehicle, and the battery 1000 can be arranged at the bottom, head or tail of the vehicle, and the battery 1000 is used to power the vehicle, for example, the battery 1000 can be used as an operating power source for the vehicle. The vehicle includes a controller and a motor (not shown), and the controller is used to control the battery 1000 to power the motor, for example, for starting, navigating and driving the vehicle. Working power requirements.

[0115] The present application also provides a method for preparing a composite foil, which can be used to prepare any composite foil 10 in the above embodiments.

[0116] Figure 6 is a flow chart of a composite foil preparation method provided in an embodiment of the present application, see Figure 6 and Figure 7 , the method comprising:

[0117] Step 601: stack at least two layers of first metal foil 3.

[0118] Step 602 : Roll the at least two layers of first metal foil 3 to a set thickness to obtain at least two first metal layers 1 having the same number of layers as the at least two layers of first metal foil 3 .

[0119] Step 603 : stacking second metal layers 2 on the two outermost first metal layers 1 of the at least two first metal layers 1 respectively.

[0120] Step 604 : splitting the at least two first metal layers 1 to obtain two composite foils 10 consisting of the first metal layer 1 and the second metal layer 2 stacked together.

[0121] In the present application, since at least the first metal layer 1 in the composite foil 10 is composed of one layer of the at least two layers of the first metal foil 3 that have been laminated, and since during the lamination process of the at least two layers of the first metal foil 3, each layer of the first metal foil 3 will be simultaneously subjected to the rolling pressure, the compression ratio is increased, and thereby the deformation degree of each layer of the first metal foil 3 is greater, it is possible to achieve a greater thickness reduction of the first metal foil 3, that is, the thickness of the first metal layer 1 obtained by lamination is thinner than the thickness of a single-layer rolled or unlaminated metal foil, that is, the thickness of the first metal layer 1 is thinner than the thickness of the aluminum foil and copper foil that constitute the current collector in the related art.

[0122] According to the above description, in the present application, since the thickness of at least the first metal layer 1 in the composite foil 10 is thinner than the aluminum foil and copper foil constituting the current collector in the related art, the composite foil 10 composed of two stacked metal layers is compared with the current collector composed of aluminum foil and copper foil stacked in the related art. The thickness of the composite foil 10 is thinner than the thickness of the current collector in the related art. In this way, when the composite foil 10 in the present application is used as a current collector, the thickness of the current collector can also become relatively thinner, which is not only beneficial to reduce the weight of the current collector, but also beneficial to reduce the amount of materials used in the manufacturing of the current collector, thereby helping to reduce costs.

[0123] As for the number of layers of the first metal foil 3 and the first metal layer 1, in a preferred embodiment, the first metal foil 3 is stacked with two layers, and two layers of the first metal foil 3 are stacked and rolled to obtain two layers of the first metal layer 1. Since the two layers of the first metal foil 3 are relatively thin, it is convenient to stack and roll the first metal foil 3. For the two layers of the first metal layer 1, the processing operations between the two adjacent first metal layers 1 can be reduced, which is conducive to the convenience of subsequent processing of the first metal layer 1.

[0124] In other embodiments, the first metal foil 3 may also be stacked with three, four or more layers, and accordingly, the obtained first metal layer 1 may also be three, four or more layers. The number of layers of the first metal foil 3 and the first metal layer 1 is relatively flexible, and can be determined according to actual needs, and this embodiment of the present application will not be elaborated in detail.

[0125] As for the materials of the first metal foil 3, the first metal layer 1 and the second metal layer 2, in the embodiment of the present application, the materials of the first metal foil 3 and the first metal layer 1 are the same as the materials of the first metal layer 1 in any one of the above-mentioned embodiments, and the material of the second metal layer 2 is the same as the materials of the second metal layer 2 in any one of the above-mentioned embodiments, which will not be repeated here.

[0126] For the above-mentioned set thickness, in a preferred embodiment, the material of the first metal foil 3 is aluminum, in which case the two layers of the first metal foil 3 are laminated and rolled, and the set thickness after the laminated rolling is 0.016 mm, that is, the thickness of the two layers of the first metal layer 1 is 0.016 mm. Such a setting can make the first metal layer 1 have a thinner thickness, and thus can also make the composite foil 10 have a thinner thickness.

[0127] In other embodiments, depending on the material of the first metal foil 3 , the set thickness of the first metal foil 3 may also be different from 0.016 mm, such as 0.015 mm or 0.017 mm.

[0128] Furthermore, step 601: before stacking at least two layers of first metal foil 3, comprises:

[0129] The first metal rolling blank is taken and subjected to multiple cold rolling, and then subjected to rough rolling and multiple intermediate rolling to form a first metal foil material 3 of a set thickness, such as Figure 7 As shown, two first metal foils 3 for stacking are provided.

[0130] Cold rolling, rough rolling and intermediate rolling are not only beneficial to comprehensively optimize the performance of the material, such as strength, toughness, ductility, etc., but also beneficial to evenly distribute the internal stress and structure of the material and improve the overall uniformity.

[0131] The above-mentioned set thickness of the first metal foil 3 is explained by assuming that the material of the first metal foil 3 is aluminum. In this case, the above-mentioned set thickness of the first metal foil 3 is 0.015 mm. In this way, the first metal foil 3 can have a thinner thickness, and further the first metal layer 1 can have a thinner thickness after lamination.

[0132] In other embodiments, depending on the material of the first metal foil 3 , the set thickness of the first metal foil 3 may be different from 0.015 mm, for example, it may be 0.014 mm or 0.016 mm.

[0133] Furthermore, step 601: stacking at least two layers of first metal foil 3, further comprising:

[0134] like Figure 7 As shown, a viscosity reducing medium 4 is coated between two adjacent layers of first metal foil 3 to reduce the adhesion between the two adjacent layers of first metal foil 3 .

[0135] Reducing the adhesion between two adjacent first metal foils 3 by using the viscosity reducing medium 4 is helpful to prevent the two first metal foils 3 from sticking together during the lamination process, thereby facilitating subsequent processing of the two first metal layers 1 after lamination.

[0136] In a preferred embodiment, the viscosity reducing medium 4 is a double oil, which can provide better lubrication and protection for the first metal foil 3 under high temperature and high load conditions, thereby further preventing adhesion between the two layers of the first metal foil 3 .

[0137] In other embodiments, the viscosity reducing medium 4 may also be mineral oil, animal or plant oil or emulsion, etc. The type of the viscosity reducing medium 4 can be flexibly selected. Specifically, it can be selected according to actual usage requirements, and the embodiments of the present application will not be elaborated on this.

[0138] For the second metal layer 2, further, in a preferred embodiment, as Figure 7 As shown, the second metal layer 2 is plated on the two outermost first metal layers 1 among the at least two first metal layers 1 .

[0139] During the plating process, metal ions are reduced and gradually deposited on the surface of the substrate to form a thin film, so that the thickness of the second metal layer 2 can be controlled, and the thickness of the second metal layer 2 can be made thinner than the first metal layer 1 by lamination. In this way, on the basis of the first metal layer 1 by lamination, the thickness of the composite foil 10 can be further made thinner by plating the second metal layer 2.

[0140] Further, step 603: stacking the second metal layer 2 on the two outermost first metal layers 1 of the at least two first metal layers 1 respectively, comprising:

[0141] Before plating the second metal layer 2, an intermediate layer (not shown) is stacked on the first metal layer 1, and the second metal layer 2 is plated on the intermediate layer to enhance the adhesion between the first metal layer 1 and the second metal layer 2 through the intermediate layer. The second metal layer 2 is indirectly plated on the first metal layer 1 through the intermediate layer.

[0142] An intermediate layer is arranged between the first metal layer 1 and the second metal layer 2, and the intermediate layer can form a chemical bond with the first metal layer 1 and the second metal layer 2, so as to increase the bonding strength between the first metal layer 1 and the second metal layer 2, that is, the adhesion between the first metal layer 1 and the second metal layer 2 can be enhanced by the intermediate layer, which is beneficial to avoid the first metal layer 1 and the second metal layer 2 from falling off, and further beneficial to ensuring the manufacturing quality of the composite foil 10.

[0143] Regarding the material of the middle layer, in the embodiment of the present application, the material of the middle layer is the same as the material of any of the middle layers in the above embodiments, and will not be repeated here.

[0144] Furthermore, in a preferred embodiment, the intermediate layer is plated on the first metal layer 1 .

[0145] With such arrangement, the intermediate layer can be formed by the thin film plated on the first metal layer 1 , which can make the intermediate layer thinner and further reduce the influence of the intermediate layer on the overall thickness of the composite foil 10 .

[0146] As for the plating method of the intermediate layer, in a preferred embodiment, the intermediate layer is plated on the first metal layer 1 by electroplating and chemical plating. Chemical plating can form a chemical bond on the surface of the first metal layer 1 to increase the adhesion between the first metal layer 1 and the intermediate layer, and electroplating can further strengthen the adhesion, so that the intermediate layer is more firmly attached to the first metal layer 1, thereby improving the durability of the intermediate layer.

[0147] In other embodiments, the intermediate layer may be plated onto the first metal layer 1 by chemical plating or electroplating, which can simplify the plating process of the intermediate layer, thereby facilitating improving work efficiency and reducing costs.

[0148] Regarding the arrangement of the intermediate layer on the first metal layer 1, in other embodiments, the intermediate layer can also be arranged on the first metal layer 1 by physical vapor deposition, chemical vapor deposition or thermal spraying. The arrangement of the intermediate layer on the first metal layer 1 is relatively flexible, and can be selected according to actual use requirements, and the embodiments of the present application will not be elaborated on this.

[0149] As for the plating method of the second metal layer 2, in a preferred embodiment, the second metal layer 2 is formed by chemical plating and electroplating. Specifically, the first metal foil 3 and the first metal layer 1 are made of aluminum, the second metal layer 2 is made of copper, and the intermediate layer is made of zinc. With reference to the electroplating method of aluminum and aluminum alloy, a conventional zinc immersion method can be used, and a copper layer is electroplated on the surface of the aluminum foil through the process of surface degreasing, alkaline etching, activation, zinc replacement, activation, electroplating copper, chromium plating or passivation, and drying, that is, the second metal layer 2 is electroplated on the surface of the first metal layer 1.

[0150] Chemical plating and electroplating can complement each other. First, a uniform second metal layer 2 can be formed by chemical plating, and then the hardness of the second metal layer 2 can be further increased by electroplating, thereby improving the wear resistance, corrosion resistance and conductivity of the second metal layer 2.

[0151] In other embodiments, depending on the material, the second metal layer 2 may be plated by other different methods, such as chemical plating or electroplating of the second metal layer 2. In this way, the plating process of the second metal layer 2 can be simplified, thereby improving work efficiency and reducing costs.

[0152] In other embodiments, the second metal layer 2 may also be formed by stacking and rolling, so that the manufacturing process of the second metal layer 2 can be simplified to a certain extent, thereby facilitating improving work efficiency and reducing costs.

[0153] Furthermore, step 603: stacking the second metal layer 2 on the two outermost first metal layers 1 of the at least two first metal layers 1 respectively, further includes:

[0154] Before plating the intermediate layer, the first metal layer 1 is degreased and deoxidized, which is beneficial to further enhance the adhesion between the first metal layer 1 and the intermediate layer, and further beneficial to further enhance the adhesion between the first metal layer 1 and the second metal layer 2.

[0155] Furthermore, step 603: stacking the second metal layer 2 on the two outermost first metal layers 1 of the at least two first metal layers 1 respectively, further includes:

[0156] The second metal layer 2 is subjected to surface treatment, such as anti-oxidation treatment of zinc plating or chromium plating, so that the second metal layer 2 can not only have better anti-oxidation and anti-corrosion properties, but also make the surface of the second metal layer 2 brighter, which is conducive to improving the surface quality of the second metal layer 2.

[0157] Further, step 604: splitting the at least two first metal layers 1 to obtain two composite foils 10 consisting of the first metal layer 1 and the second metal layer 2 stacked together, including:

[0158] like Figure 7 As shown, annealing, splitting of the at least two first metal layers 1, degreasing and slitting of the stacked first metal layer 1 and the second metal layer 2 are performed to obtain two composite foils 10 consisting of the stacked first metal layer 1 and the second metal layer 2.

[0159] Annealing can not only relieve the internal stress generated during the processing and reduce the risk of deformation and cracking, but also increase plasticity to facilitate subsequent processing; degreasing can prevent oil stains on the composite foil 10 from affecting subsequent use.

[0160] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A composite foil, characterized in that: include: A first metal layer (1); A second metal layer (2), the second metal layer (2) and the first metal layer (1) are stacked; At least one of the first metal layer (1) and the second metal layer (2) is a rolled layer; The at least two stacked layers of the same metal foil are used to form at least two rolled layers having the same number of layers as the at least two layers of the same metal foil after stacking and slitting.

2. The composite foil according to claim 1, characterized in that: The first metal layer (1) is the rolled layer, and the second metal layer (2) is the plated layer.

3. The composite foil according to claim 2, characterized in that: The composite foil (10) further comprises: An intermediate layer, wherein the intermediate layer is arranged between the first metal layer (1) and the second metal layer (2), the second metal layer (2) is plated on the intermediate layer, and the intermediate layer is used to enhance the adhesion between the first metal layer (1) and the second metal layer (2).

4. The composite foil according to claim 3, characterized in that: The intermediate layer is plated on the first metal layer (1).

5. The composite foil according to claim 3 or 4, characterized in that: The thickness of the intermediate layer is 10nm-1000nm.

6. The composite foil according to any one of claims 1 to 4, characterized in that: The thickness of the first metal layer (1) is 4 μm-12 μm; and / or, The thickness of the second metal layer (2) is 0.1 μm-5 μm.

7. A pole piece, characterized in that: include: The composite foil (10) according to any one of claims 1 to 6, wherein the composite foil (10) is a current collector; A positive electrode layer (20), the positive electrode layer (20) being stacked on the first metal layer (1) in the current collector; A negative electrode layer (30), the negative electrode layer (30) being stacked on the second metal layer (2) in the current collector.

8. A battery, characterized in that: include: The pole piece (100) as claimed in claim 7.

9. The battery according to claim 8, characterized in that The pole piece (100) is stacked in a plurality of layers; the pole piece (100) further comprises a first insulating edge sealing layer (40) and a second insulating edge sealing layer (50), the first insulating edge sealing layer (40) being arranged on the first metal layer (1) and surrounding a circumference of the positive electrode layer (20), and the second insulating edge sealing layer (50) being arranged on the second metal layer (2) and surrounding a circumference of the negative electrode layer (30); The first insulating edge sealing layer (40) and the second insulating edge sealing layer (50) arranged opposite to each other in two adjacent pole pieces (100) are used to bond the two adjacent pole pieces (100).

10. An electrical device, characterized in that: include: A battery (1000) according to claim 8 or 9.

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