Metal electrode sheet, metal electrode sheet preparation method, electrode sheet cutting device, secondary battery, and electrical apparatus

Abstract

A metal electrode sheet, a metal electrode sheet preparation method, an electrode sheet cutting device, a secondary battery, and an electrical apparatus. The metal electrode sheet comprises a main body part and an insulating part. The main body part comprises a metal layer. The insulating part comprises a side surface insulating layer. The side surface insulating layer is arranged on a side surface of the main body part. The side surface insulating layer arranged on the side surface of the main body part can effectively inhibit the deposition and growth of pulverized negative electrode metal material at the cutting position of the metal electrode sheet, thereby improving the safety performance of the secondary battery.

Description

A metal electrode, a method for preparing the metal electrode, an electrode cutting device, a secondary battery, and an electrical device.

[0001] Cross-referencing

[0002] This application references Chinese Patent Application No. 2024106668049, filed on May 27, 2024, entitled "A metal electrode sheet, a method for preparing a metal electrode sheet, an electrode sheet cutting device, a secondary battery, and an electrical device", which is incorporated herein by reference in its entirety. Technical Field

[0003] This application relates to the field of secondary battery technology, and in particular to a metal electrode, a method for preparing the metal electrode, an electrode cutting device, a secondary battery, and an electrical device. Background Technology

[0004] In recent years, rechargeable batteries have been widely used in energy storage power systems such as hydropower, thermal power, wind power, and solar power plants, as well as in power tools, electric bicycles, electric motorcycles, electric cars, military equipment, aerospace, and many other fields. With the increasing application of rechargeable batteries, higher requirements have been placed on their cycle performance and service life.

[0005] Metal batteries possess higher energy density and represent the future direction of rechargeable batteries. However, metal batteries are prone to short-circuit failures, leading to safety issues. Improving the safety of metal batteries has become a pressing technical problem to be solved in this field.

[0006] Summary of the Invention

[0007] This application is made in view of the above-mentioned issues, and its purpose is to provide a metal electrode sheet that can improve safety, a method for preparing the metal electrode sheet, an electrode sheet cutting device, a secondary battery, and an electrical device.

[0008] A first aspect of this application provides a metal electrode sheet, comprising: a main body portion and an insulating portion, the main body portion including a metal layer, and the insulating portion including a side insulating layer disposed on a side surface of the main body portion.

[0009] The side insulating layer set on the side surface of the main body can effectively suppress the deposition and growth of pulverized negative electrode metal material at the cut-off site of the metal electrode, thereby improving the safety performance of the secondary battery.

[0010] In any embodiment, the thickness S of the side insulating layer is less than or equal to 14 μm.

[0011] The thickness S of the side insulation layer within the above range can increase the energy density of the metal electrode.

[0012] In any embodiment, the insulating portion further includes a surface insulating layer disposed on the upper and lower surfaces of the main body portion and adjacent to the side surfaces.

[0013] The surface insulating layer completely insulates the cut-off sites of the metal electrode, further reducing the probability of dendrite growth at the cut-off sites and further improving the safety performance of the secondary battery.

[0014] In any embodiment, the width L of the surface insulating layer on both the upper and lower surfaces is 1μm-500μm.

[0015] The fact that the width L of the surface insulating layer on both the upper and lower surfaces is within the above range can further reduce the probability of dendrite growth at the cut-off sites of the metal electrode and improve the safety performance of the secondary battery.

[0016] In any embodiment, the surface insulating layer and the adjacent side insulating layer are connected to each other at the corner of the main body portion.

[0017] The interconnected surface insulation layer and side insulation layer at the corner of the main body can further improve the insulation of the metal electrode cutting position, reduce the probability of dendrite growth at the metal electrode cutting position, and improve the safety performance of the secondary battery.

[0018] In any embodiment, the metal layer includes one or more of lithium metal, sodium metal, potassium metal, magnesium metal, and alloys thereof.

[0019] This metal electrode is not only suitable for lithium batteries but also for other metal batteries, making it widely applicable.

[0020] In any embodiment, the main body portion further includes a current collector, and the metal layer is disposed on at least one side of the current collector.

[0021] In any embodiment, the insulating portion comprises a polymer.

[0022] In any embodiment, the polymer is one or more of epoxy resin, polypropylene, and polyimide.

[0023] The above-mentioned materials have excellent bonding properties and electrolyte resistance while possessing curing insulation properties, making them suitable for use in secondary batteries.

[0024] A second aspect of this application provides a method for preparing a metal electrode sheet, the method comprising: obtaining a material containing a metal layer; cutting and cross-sectionally processing the material along its thickness direction to obtain a metal electrode sheet, wherein the metal electrode sheet comprises: a main body portion, the main body portion including a metal layer, and an insulating portion, the insulating portion including a side insulating layer disposed on a side surface of the main body portion.

[0025] In any embodiment, the step of cutting and cross-sectional processing the material along its thickness direction to obtain a metal electrode sheet specifically includes: moving a cutting device with an insulating curing liquid disposed on its surface along the thickness direction of the material to cut the material along its thickness direction while simultaneously allowing the insulating curing liquid to adhere to the cut surface of the material to obtain a metal electrode sheet.

[0026] While cutting the material into metal electrode sheets, the insulation part is wrapped at the cut point of the material, which can not only improve the safety performance of the secondary battery, but also without sacrificing the processing efficiency of the secondary battery.

[0027] In any embodiment, the step of cutting and sectioning the material along its thickness direction to obtain a metal electrode sheet specifically includes: moving the cutting device closer to the material to cut the material along its thickness direction, and then continuing to move the cutting device in the original direction so that the lower end of the cutting device is immersed in an insulating curing liquid disposed below the material; and moving the cutting device away from the material so that the insulating curing liquid adheres to the cut surface of the material.

[0028] The above configuration enables the cutting device to repeatedly impregnate the insulating curing liquid during the reciprocating cutting movement, thereby optimizing the safety of the secondary battery while improving the coating efficiency of the insulation layer.

[0029] In any embodiment, the method further includes: the viscosity of the insulating curing liquid at room temperature is less than or equal to 4 mPa·s.

[0030] Insulating curing liquids with viscosity within the above range can effectively coat the sides of the metal electrode body and the upper surface adjacent to the sides, improving the molding quality of the insulating part.

[0031] In any embodiment, the insulating curing liquid includes one or more of epoxy resin, polypropylene, and polyimide.

[0032] A third aspect of this application provides an electrode cutting apparatus, including a transport table and a cutting device. The transport table is configured to transport material containing a metal layer in a horizontal direction. A through groove extending in the depth direction of the transport table is provided on the surface of the transport table, and an impregnation device is provided below the through groove. The cutting device is disposed in a longitudinal direction above the through groove of the transport table and is configured to cut the material. After cutting, the lower end of the cutting device is impregnated through the through groove with an insulating curing liquid contained in the impregnation device.

[0033] This electrode cutting equipment can simultaneously coat the cut area of ​​the metal electrode with insulating curing liquid, improving production efficiency and enhancing the safety performance of secondary batteries.

[0034] In any embodiment, the electrode cutting equipment further includes a curing device, which is located downstream of the cutting device and configured to cure the insulating curing liquid coating the cut material.

[0035] In any embodiment, the curing apparatus includes one or more of a fan and a heating device.

[0036] In any embodiment, the cutting device includes an upper cutter with a first surface located on the upstream side, and the longitudinal movement depth of the upper cutter is configured such that the minimum distance D between the first surface of the upper cutter and the second surface of the groove opposite to it is greater than or equal to 3 μm.

[0037] In any embodiment, the vertical movement depth of the upper cutter is configured such that the minimum distance D between the first surface of the upper cutter and the second surface of the groove opposite to it is 3μm-10μm.

[0038] The minimum distance D between the first surface of the upper cutter and the second surface opposite to the groove is within the above range, which makes the side insulation layer of the metal electrode sheet have a certain thickness and the surface insulation layer have a certain width, which is beneficial to improving the coating quality of the insulation layer at the corner of the metal electrode sheet at the cutting position.

[0039] The fourth aspect of this application provides a secondary battery, the secondary battery including a negative electrode sheet, the negative electrode sheet including a metal electrode sheet of the first aspect, a metal electrode sheet prepared by the preparation method of the second aspect, or an electrode sheet cut by the electrode sheet cutting device of the third aspect.

[0040] In any embodiment, the secondary battery includes a stacked battery.

[0041] Stacked batteries are manufactured by cutting the electrode sheets and then stacking them. At the cut position of the metal negative electrode, pulverized metal material is prone to grow, forming dendrites, which can cause short circuits in the secondary battery and lead to battery failure.

[0042] In any embodiment, the secondary battery includes a lithium metal battery.

[0043] The fifth aspect of this application provides an electrical device, which includes the secondary battery of the fourth aspect. Attached Figure Description

[0044] Figure 1 is a schematic diagram of a metal electrode sheet according to an embodiment of this application;

[0045] Figure 2 is a schematic diagram of a method for preparing a metal electrode sheet according to an embodiment of this application;

[0046] Figure 3 is a perspective view of an electrode cutting apparatus according to an embodiment of this application;

[0047] Figure 4 is a front view of an electrode cutting apparatus according to an embodiment of this application;

[0048] Figure 5 is a schematic diagram of the cutting process according to an embodiment of this application;

[0049] Figure 6 is a schematic diagram of a secondary battery according to an embodiment of this application;

[0050] Figure 7 is an exploded view of the secondary battery according to an embodiment of this application shown in Figure 6;

[0051] Figure 8 is a schematic diagram of a battery module according to one embodiment of this application;

[0052] Figure 9 is a schematic diagram of a battery pack according to an embodiment of this application;

[0053] Figure 10 is an exploded view of a battery pack according to an embodiment of this application, as shown in Figure 9;

[0054] Figure 11 is a schematic diagram of an electrical device using a secondary battery as a power source according to an embodiment of this application.

[0055] Explanation of reference numerals in the attached figures:

[0056] 1 Battery pack; 2 Upper housing; 3 Lower housing; 4 Battery module; 5 Secondary battery; 51 Housing; 52 Electrode assembly; 53 Top cover assembly; 6 Metal electrode sheet; 61 Main body; 62 Insulating part; 611 Metal layer; 612 Current collector; 621 Side insulation layer; 622 Surface insulation layer; 200 Electrode sheet cutting equipment; 210 Transmission table; 211 Through groove; 212 Impregnation device; 220 Cutting device; 221 Upper cutter; 2211 First surface; 230 Material. Detailed Implementation

[0057] The following detailed description, with appropriate reference to the accompanying drawings, discloses embodiments of the metal electrode sheet, the method for preparing the metal electrode sheet, the electrode sheet cutting equipment, the secondary battery, and the power-consuming device of this application. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided for the purpose of enabling those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0058] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints 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 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0059] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0060] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0061] Unless otherwise specified, all steps in this 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 it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0062] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0063] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0064] Metal batteries are prone to negative electrode metal pulverization during cycling. Pulverized negative electrode metal materials (such as pulverized lithium) are easily grown outward from the metal negative electrode cut-off site to the edge under the action of an electric field, causing short circuit between the positive and negative electrodes, and even causing the battery to catch fire or explode, which poses a great safety risk.

[0065] In view of this, an embodiment of the present application provides a metal electrode sheet, as shown in FIG1. ​​The metal electrode sheet 6 includes a main body portion 61 and an insulating portion 62. The main body portion 61 includes a metal layer 611, and the insulating portion 62 includes a side insulating layer 621, which is disposed on the side surface of the main body portion 61.

[0066] The side insulating layer 621 disposed on the side surface of the main body 61 can effectively suppress the deposition and growth of pulverized negative electrode metal material at the metal electrode cutting site, thereby improving the safety performance of the secondary battery.

[0067] In some embodiments, the thickness S of the side insulating layer 621 is less than or equal to 14 μm.

[0068] In some embodiments, the thickness S of the side insulating layer 621 can be selected as 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm or any value range between the two.

[0069] The thickness S of the side insulation layer within the above range can increase the energy density of the metal electrode.

[0070] In some embodiments, the insulating portion 62 further includes a surface insulating layer 622 disposed on the upper and lower surfaces of the main body portion 61 and adjacent to the side surfaces.

[0071] The surface insulating layer completely insulates the cut-off sites of the metal electrode, further reducing the probability of dendrite growth at the cut-off sites and further improving the safety performance of the secondary battery.

[0072] In some embodiments, the width L of the surface insulating layer on both the upper and lower surfaces is 1 μm-500 μm.

[0073] In some embodiments, the width L of the surface insulating layer on the upper and lower surfaces can be selected as 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 30 μm, 50 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm or any value range between the two.

[0074] The fact that the width L of the surface insulating layer on both the upper and lower surfaces is within the above range can further reduce the probability of dendrite growth at the cut-off sites of the metal electrode and improve the safety performance of the secondary battery.

[0075] In some embodiments, the surface insulating layer 622 and the adjacent side insulating layer 621 are connected to each other at the corner of the main body portion 61.

[0076] The surface insulating layer 622 and the side insulating layer 621, which are connected to each other at the corner of the main body 61, can further improve the insulation of the metal electrode cutting position, reduce the probability of dendrite growth at the metal electrode cutting position, and improve the safety performance of the secondary battery.

[0077] In some embodiments, the metal layer 611 includes one or more of lithium metal, sodium metal, potassium metal, magnesium metal, and alloys thereof.

[0078] An alloy is an alloy formed by a metal and other metals or non-metals. Other metals include tin (Sn), zinc (Zn), aluminum (Al), magnesium (Mg), silver (Ag), gold (Au), gallium (Ga), indium (In), and tin (Pt); other non-metals include boron (B), carbon (C), and silicon (Si).

[0079] This metal electrode is not only suitable for lithium batteries but also for other metal batteries, making it widely applicable.

[0080] In some embodiments, the main body portion 61 further includes a current collector 612, wherein the metal layer 611 is disposed on at least one side of the current collector 612.

[0081] In some embodiments, the current collector 612 comprises a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. The composite current collector may include a polymeric material substrate and a metal layer formed on at least one surface of the polymeric material substrate. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymeric material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0082] In some embodiments, the insulating portion 62 comprises a polymer.

[0083] In some embodiments, the polymer includes one or more of epoxy resin, polypropylene, and polyimide.

[0084] The above-mentioned materials have excellent bonding properties and electrolyte resistance while possessing curing insulation properties, making them suitable for use in secondary batteries.

[0085] As shown in Figure 2, one embodiment of this application provides a method 100 for preparing a metal electrode sheet, including: step S110, obtaining a material containing a metal layer; step S120, cutting and cross-sectional processing the material along the thickness direction to obtain a metal electrode sheet, wherein the metal electrode sheet includes: a main body portion and an insulating portion, the main body portion includes a metal layer, the insulating portion includes a side insulating layer, and the side insulating layer is disposed on the side surface of the main body portion.

[0086] In some implementations, the material includes one or more of rolls and sheets.

[0087] In some embodiments, step S120, which involves cutting and cross-sectional processing the material along its thickness direction to obtain a metal electrode sheet, specifically includes: moving a cutting device with an insulating curing liquid disposed on its surface along the thickness direction of the material to cut the material along its thickness direction while simultaneously allowing the insulating curing liquid to adhere to the cut surface of the material to obtain a metal electrode sheet.

[0088] While cutting the material into metal electrode sheets, the insulation part is wrapped at the cut point of the material, which can not only improve the safety performance of the secondary battery, but also without sacrificing the processing efficiency of the secondary battery.

[0089] In some embodiments, step S120, which involves cutting and sectioning the material along its thickness direction to obtain a metal electrode sheet, specifically includes: moving the cutting device closer to the material to cut it along its thickness direction, and then continuing to move the cutting device along its original direction so that the lower end of the cutting device is immersed in an insulating curing liquid disposed below the material; and moving the cutting device away from the material so that the insulating curing liquid adheres to the cut surface of the material.

[0090] In some embodiments, the cutting device includes an upper cutter. The lower end of the upper cutter is immersed in an insulating curing liquid disposed below the material. When the cutting device is pulled away from the material, the insulating curing liquid adheres to the cut surface of the material. In the next cutting process, as the upper cutter cuts downwards towards the material, the insulating curing electrolyte remaining on the surface of the upper cutter adheres to the cut position. After the lower end of the upper cutter is immersed in the insulating curing liquid disposed below the material, when the cutting device is pulled away from the material, the insulating curing liquid re-adheres to the cut surface of the material.

[0091] The above configuration enables the cutting device to repeatedly impregnate the insulating curing liquid during the reciprocating cutting movement, thereby optimizing the safety of the secondary battery while improving the coating efficiency of the insulation layer.

[0092] In some embodiments, the insulating curing liquid includes one or more of epoxy resin, polypropylene, and polyimide. In some embodiments, the viscosity of the insulating curing liquid at room temperature is less than or equal to 4 mPa·s.

[0093] Insulating curing liquids with viscosity within the above range can effectively coat the sides of the metal electrode body and the upper surface adjacent to the sides, improving the molding quality of the insulating part.

[0094] As shown in Figures 3 and 4, this application also provides an electrode cutting device 200, including a transfer table 210 and a cutting device 220. The transfer table 210 is configured to transfer material 230 containing a metal layer in the horizontal direction. The surface of the transfer table 210 is provided with a through groove 211 extending in the depth direction of the table surface. An impregnation device 212 is provided below the through groove 211. The cutting device 220 is arranged in the longitudinal direction above the through groove 211 of the transfer table and is configured to cut the material 230. After cutting, the lower end of the cutting device 220 is impregnated through the through groove 211 with an insulating curing liquid contained in the impregnation device 212.

[0095] This electrode cutting equipment can simultaneously coat the cut area of ​​the metal electrode with insulating curing liquid, improving production efficiency and enhancing the safety performance of secondary batteries.

[0096] In some embodiments, the electrode cutting apparatus 200 further includes a curing device (not shown), which is located downstream of the cutting apparatus 220 and is configured to cure the insulating curing liquid coated on the material.

[0097] It can be understood that downstream of the cutting device 220 refers to the side pointing from the cutting device in the material conveying direction.

[0098] In some embodiments, the curing apparatus includes one or more of a fan and a heating device.

[0099] The curing device is configured to cure the insulating curing liquid using one or more methods such as airflow and heating. This curing device enables the insulating curing liquid to cure rapidly, which is beneficial for improving the processing efficiency of metal electrode sheets.

[0100] In some embodiments, as shown in FIG5, the cutting device 220 includes an upper cutter 221, the upper cutter 221 including a first surface 2211 located on the upstream side, and the moving depth of the upper cutter in the longitudinal direction is configured such that the minimum distance D between the first surface 2211 of the upper cutter and the second surface opposite to the groove 211 is greater than or equal to 3 μm.

[0101] The upstream side refers to the side of the upper cutter 221 that is closer to the material supply direction.

[0102] In some embodiments, the cutting device 220 further includes a lower cutter 222, which is disposed adjacent to the second surface of the groove 211.

[0103] The lower cutter 222 and the upper cutter 221 can work together to improve cutting efficiency.

[0104] In some embodiments, the longitudinal movement depth of the upper cutter 221 is configured such that the minimum distance D between the first surface 2211 of the upper cutter and the second surface opposite to the groove 211 can be selected as 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm or any value range between the two.

[0105] During the downward or upward movement of the upper cutter, the insulating curing liquid is squeezed out by the gap between the first surface of the upper cutter and the second surface of the groove opposite to it, overflowing onto the upper and / or lower surface of the metal electrode sheet. Experimental results show that the thickness S of the side insulation layer and the width L of the surface insulation layer on the upper and lower surfaces of the metal electrode sheet are positively correlated with the minimum distance D between the first surface of the upper cutter and the second surface of the groove opposite to it.

[0106] The minimum distance D between the first surface of the upper cutter and the second surface opposite to the groove is within the above range, which makes the side insulation layer of the metal electrode sheet have a certain thickness and the surface insulation layer have a certain width, which is beneficial to improving the coating quality of the insulation layer at the corner of the metal electrode sheet at the cutting position.

[0107] In some embodiments, the vertical movement depth of the upper cutter 221 is configured such that the minimum distance D between the first surface 2211 of the upper cutter and the second surface of the groove 211 opposite to it is 3 μm-10 μm.

[0108] The minimum distance D between the first surface of the upper cutter and the second surface opposite to the groove is within the above range, which enables the metal electrode to simultaneously have good cutting position insulation and cutting quality.

[0109] In some embodiments, this application provides a secondary battery, which includes a negative electrode sheet, which includes a metal electrode sheet of any embodiment, a metal electrode sheet prepared by any embodiment of the preparation method, or an electrode sheet cut by any embodiment of the electrode sheet cutting device.

[0110] In some embodiments, the secondary battery includes a positive electrode. The positive electrode includes a positive current collector and a positive electrode film layer disposed on at least one surface of the positive current collector, the positive electrode film layer including a positive electrode active material.

[0111] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0112] In some embodiments, the positive 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 substrate and a metal layer formed on at least one surface of the polymer substrate. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0113] In some embodiments, the positive electrode active material may be a known battery positive electrode active material. As an example, the positive electrode active material may include at least one of the following materials: lithium phosphates with an olivine structure, lithium transition metal oxides, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium transition metal oxides include, but are not limited to, lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, and lithium nickel cobalt manganese oxides (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05 At least one of O2 and its modified compounds. Examples of lithium phosphates with an olivine structure include, but are not limited to, lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites.

[0114] In some embodiments, the positive electrode film layer may optionally include a binder. As an example, the binder may include at least one selected from polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0115] In some embodiments, the positive electrode film may optionally include a conductive agent. As an example, the conductive agent may include at least one selected from superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0116] In some embodiments, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive active material, conductive agent, binder and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto the positive electrode current collector, and then obtaining the positive electrode sheet after drying, cold pressing and other processes.

[0117] In some implementations, the secondary battery also includes an electrolyte.

[0118] The electrolyte acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific restrictions on the type of electrolyte; it can be selected according to requirements. For example, the electrolyte can be liquid, gel, or entirely solid.

[0119] In some embodiments, the electrolyte is an electrolyte solution. The electrolyte solution includes an electrolyte salt and a solvent.

[0120] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0121] In some embodiments, the solvent may be selected from ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and... Diethyl sulfone and ether solvents include one or more of the following: ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol diethyl ether, diisopropyl ether, dibutyl ether, diethylene glycol dibutyl ether, 1,4-dimethoxybutane, 1,4-diethoxybutane, 1,3-dioxolane, tetrahydrofuran, 15-crown ether-5, 12-crown ether-4, and 18-crown ether-6.

[0122] In some embodiments, the electrolyte may optionally include additives. For example, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives that can improve certain battery performance, such as additives that improve battery overcharge performance, additives that improve battery high-temperature or low-temperature performance, etc.

[0123] In some embodiments, the secondary battery also includes a separator. This application does not impose any particular limitation on the type of separator; any known porous separator with good chemical and mechanical stability can be selected.

[0124] In some embodiments, the material of the separator can be selected from at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, polyimide, 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.

[0125] In some implementations, the secondary battery includes a stacked battery.

[0126] Stacked batteries are manufactured by cutting the electrode sheets and then stacking them. At the cut position of the metal negative electrode, pulverized metal material is prone to grow, forming dendrites, which can cause short circuits in the secondary battery and lead to battery failure.

[0127] In some embodiments, the positive electrode, the separator, and the negative electrode can be fabricated into an electrode assembly using a winding process or a stacking process.

[0128] In some embodiments, the secondary battery may include an outer packaging. This outer packaging can be used to encapsulate the electrode assembly and electrolyte described above.

[0129] In some embodiments, the outer packaging can be a rigid shell, such as a rigid plastic shell, aluminum shell, or steel shell. The outer packaging can also be a flexible package, such as a pouch. The material of the flexible package can be plastic, such as one or more of polypropylene (PP), polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0130] This application does not impose any particular limitation on the shape of the secondary battery; it can be cylindrical, square, or any other arbitrary shape. Figure 6 shows a square secondary battery 5 as an example.

[0131] In some embodiments, as shown in FIG7, the outer packaging may include a housing 51 and a cover plate 53. The housing 51 may include a base plate and side plates connected to the base plate, the base plate and side plates enclosing a receiving cavity. The housing 51 has an opening communicating with the receiving cavity, and the cover plate 53 is used to cover the opening to close the receiving cavity. The positive electrode, negative electrode, and separator may be formed into an electrode assembly 52 by a winding process or a stacking process. The electrode assembly 52 is encapsulated in the receiving cavity. Electrolyte is immersed in the electrode assembly 52. ​​The secondary battery 5 may contain one or more electrode assemblies 52, which can be adjusted according to requirements.

[0132] The method for preparing the secondary battery described in this application is well known. In some embodiments, a positive electrode, a separator, a negative electrode, and an electrolyte can be assembled to form a secondary battery. As an example, the positive electrode, separator, and negative electrode can be formed into an electrode assembly through a winding or stacking process. The electrode assembly is then placed in an outer packaging, dried, and injected with an electrolyte. After vacuum sealing, settling, formation, and shaping, a secondary battery is obtained.

[0133] In some embodiments of this application, the secondary battery according to this application can be assembled into a battery module, and the number of secondary batteries contained in the battery module can be multiple, the specific number of which can be adjusted according to the application and capacity of the battery module.

[0134] Figure 8 is a schematic diagram of a battery module 4 as an example. As shown in Figure 7, in the battery module 4, multiple secondary batteries 5 can be arranged sequentially along the length of the battery module 4. Of course, they can also be arranged in any other arbitrary way. Furthermore, the multiple secondary batteries 5 can be fixed in place using fasteners.

[0135] Optionally, the battery module 4 may also include a housing with a receiving space in which a plurality of secondary batteries 5 are received.

[0136] In some embodiments, the battery modules described above can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be adjusted according to the application and capacity of the battery pack.

[0137] Figures 9 and 10 are schematic diagrams of a battery pack 1 as an example. As shown in Figures 9 and 10, the battery pack 1 may include a battery box and multiple battery modules 4 disposed within the battery box. The battery box includes an upper box 2 and a lower box 3. The upper box 2 covers the lower box 3, forming a closed space for accommodating the battery modules 4. The multiple battery modules 4 can be arranged in any manner within the battery box.

[0138] In some embodiments, this application provides an electrical device including a secondary battery of any embodiment.

[0139] The electrical devices mentioned may include, but are not limited to, mobile devices (such as mobile phones, tablets, 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.

[0140] The electrical device can be equipped with a secondary battery, battery module, or battery pack according to its usage requirements.

[0141] Figure 11 is a schematic diagram of an example electrical device. This device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. To meet the device's requirements for high power and high energy density, a battery pack or battery module can be used.

[0142] Another example of an electrical device could be a mobile phone, tablet, or laptop. These devices typically require a slim and lightweight design and can use rechargeable batteries as their power source.

[0143] Example

[0144] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0145] I. Preparation Method

[0146] Example 1

[0147] 1) Preparation of negative electrode sheet

[0148] The cutting device provided in this application embodiment is used to cut lithium aluminum coils; in embodiment 1, the moving depth of the cutting device in the longitudinal direction is configured such that the minimum distance D between the first surface of the cutting device and the second surface opposite to the groove is 10um, the cutting time is 3 seconds, and the cutting time includes the total time spent by the cutter cutting downward from the initial position, being impregnated with the insulating curing liquid, and then being pulled upward to the initial position in one cutting process; the insulating curing liquid is epoxy resin.

[0149] The negative electrode sheet was cut into sheets with an active material layer length of 51 mm and a width of 41 mm. After cold air curing, the surface insulating layer was observed under an electron microscope.

[0150] 2) Preparation of positive electrode sheet

[0151] LiNi, the positive electrode active material 0.8 Co 0.1 Mn0.1 O2 (NCM811), conductive agent acetylene black, and binder polyvinylidene fluoride (PVDF) are dissolved in N-methylpyrrolidone (NMP) at a weight ratio of 90:5:5. After thorough mixing, a positive electrode slurry is obtained. This slurry is then uniformly coated onto a positive electrode current collector, followed by drying, cold pressing, and slitting to obtain the positive electrode sheet. The active material layer of the positive electrode sheet is 50 mm long and 40 mm wide.

[0152] 3) Battery manufacturing

[0153] The diaphragm is a PE diaphragm. The diaphragm is 47mm wide, and it is 2mm wider on each side relative to the negative electrode.

[0154] The negative and positive electrodes are stacked layer by layer, with a total of 11 layers for the negative electrode and 10 layers for the positive electrode. An extra layer is wrapped around the outermost part of the stack to finish it off, thus obtaining the battery cell.

[0155] Examples 2-5

[0156] The preparation methods of Examples 2-5 are basically the same as those of Example 1, except that the cutting speed T or the minimum distance D between the first surface of the cutting device and the second surface opposite to the groove is adjusted. The specific parameters are shown in Table 1.

[0157] Comparative Example 1

[0158] The preparation method of Comparative Example 1 is basically the same as that of Example 1, except that no curing liquid is placed under the groove.

[0159] Table 1

[0160] II. Performance Testing

[0161] (1) Insulation layer test

[0162] The dimensions of the insulating layer were measured using a scanning electron microscope.

[0163] (2) Lithium plating test

[0164] The above-mentioned batteries were subjected to a cyclic test under a clamping force of 0.5 MPa. The specific steps were as follows: the batteries were charged at a constant current of 0.5C to a voltage of 4.3V, charged at a constant voltage of U1 to 0.05C, and left to stand for 10 minutes; the batteries were discharged at a constant current of 0.5C to a voltage of 2.8V, and left to stand for 10 minutes; the above steps were repeated for 100 cycles, and then the cells were disassembled; cells that did not reach 100 cycles were also marked.

[0165] After disassembling the battery and separating the positive electrode plate from the negative electrode plate, observe whether there is lithium overflow growth at the cutting position of the negative electrode plate. If there is no lithium overflow growth at the cutting position of the negative electrode plate or the cycle has not reached 100 turns, it is judged as qualified; if there is lithium overflow growth at the cutting position of the negative electrode plate, it is judged as unqualified.

[0166] III. Analysis of Test Results of Each Example and Comparative Example

[0167] Prepare secondary batteries of each example and comparative example according to the above method, and measure various performance parameters. The results are shown in Table 2.

[0168] Table 2

[0169] As can be seen from Table 2, the pole piece cutting equipment provided by the embodiments of the present application can coat the side and upper and lower surfaces of the negative electrode plate with an insulating curing liquid while cutting the material, so that insulating layers can be provided on the side and the edges of the upper and lower surfaces close to the side of the lithium metal pole piece, reducing the growth of lithium metal at the cutting position, improving the cycle life and safety performance of the battery, and at the same time improving production efficiency.

[0170] It should be noted that the present application is not limited to the above embodiments. The above embodiments are only examples, and embodiments with the same structure and the same effect as the technical idea within the technical solution scope of the present application are included in the technical scope of the present application. In addition, within the scope not departing from the gist of the present application, various modifications that can be thought of by those skilled in the art to the embodiments, and other ways constructed by combining some constituent elements of the embodiments are also included in the scope of the present application.

Claims

1. A metal tab characterized by, include: The main body portion includes a metal layer, and An insulating portion, the insulating portion including a side insulating layer disposed on the side surface of the main body portion.

2. The metal tab of claim 1, wherein The thickness S of the side insulating layer is less than or equal to 14 μm.

3. The metal tab according to claim 1 or 2, characterized in that, The insulating portion further includes a surface insulating layer disposed on the upper and lower surfaces of the main body portion and adjacent to the side surfaces.

4. The metal tab of claim 3, wherein, The width L of the surface insulating layer on both the upper and lower surfaces is 1μm-500μm.

5. The metal tab of claim 3 or 4, wherein, The surface insulating layer and the adjacent side insulating layer are connected to each other at the corner of the main body.

6. The metal tab of any one of claims 1 to 5, wherein, The metal layer includes one or more of lithium metal, sodium metal, potassium metal, magnesium metal, and their alloys.

7. The metal tab of any one of claims 1 to 6, wherein, The main body also includes a current collector, and the metal layer is disposed on at least one side of the current collector.

8. The metal tab of any one of claims 1 to 7, wherein, The insulating portion comprises a polymer.

9. The metal electrode sheet according to claim 8, characterized in that, The polymer is one or more of epoxy resin, polypropylene, and polyimide.

10. A method for preparing a metal electrode sheet, characterized in that, The method includes: Obtain materials containing a metal layer; The material is cut and cross-sectionally processed along its thickness direction to obtain a metal electrode sheet, wherein the metal electrode sheet includes: a main body portion, the main body portion including a metal layer, and an insulating portion, the insulating portion including a side insulating layer, the side insulating layer being disposed on the side surface of the main body portion.

11. The preparation method according to claim 10, characterized in that, The step of cutting and cross-sectional processing the material along its thickness direction to obtain the metal electrode sheet specifically includes: A cutting device with an insulating curing liquid on a moving surface along the thickness direction of the material is used to cut the material along its thickness direction while simultaneously adhering the insulating curing liquid to the cut surface of the material to obtain a metal electrode sheet.

12. The preparation method according to claim 10 or 11, characterized in that, The step of cutting and cross-sectional processing the material along its thickness direction to obtain the metal electrode sheet specifically includes: The cutting device is moved toward the material to cut the material along the thickness direction, and then the cutting device is moved in the original direction so that the lower end of the cutting device is immersed in the insulating curing liquid located below the material. Move the cutting device away from the material so that the insulating curing liquid adheres to the cut surface of the material.

13. The preparation method according to claim 11 or 12, characterized in that, The method further includes: The viscosity of the insulating curing liquid at room temperature is less than or equal to 4 mPa·s.

14. The preparation method according to any one of claims 11 to 13, characterized in that, The insulating curing liquid includes one or more of epoxy resin, polypropylene, and polyimide.

15. An electrode cutting device, characterized in that... Includes a transfer table configured to transfer material containing a metal layer in a horizontal direction, the surface of the transfer table having a through groove extending in the depth direction of the table surface, and an impregnation device disposed below the through groove; A cutting device is arranged in the longitudinal direction above the through groove of the conveyor table. It is configured to cut the material, and then the lower end of the cutting device is immersed in the insulating curing liquid contained in the immersion device through the through groove.

16. The electrode cutting equipment according to claim 15, characterized in that, The electrode cutting equipment also includes a curing device, which is located downstream of the cutting device and is configured to cure the insulating curing liquid coating the material after cutting.

17. The electrode cutting equipment according to claim 16, characterized in that, The curing device includes one or more of a fan and a heating device.

18. The electrode cutting apparatus according to any one of claims 15 to 17, characterized in that, The cutting device includes an upper cutter, which includes a first surface located on the upstream side. The longitudinal movement depth of the upper cutter is configured such that the minimum distance D between the first surface of the upper cutter and the second surface of the groove opposite to it is greater than or equal to 3 μm.

19. The electrode cutting equipment according to claim 18, characterized in that, The vertical movement depth of the upper cutter is configured such that the minimum distance D between the first surface of the upper cutter and the second surface of the groove opposite to it is 3μm-10μm.

20. A secondary battery, characterized in that, The secondary battery includes a negative electrode sheet, which includes a metal electrode sheet according to any one of claims 1 to 9, a metal electrode sheet prepared by any one of claims 10 to 14, or an electrode sheet cut by any one of claims 15 to 19.

21. The secondary battery according to claim 20, characterized in that, The secondary battery includes a stacked battery.

22. The secondary battery according to claim 20, characterized in that, The secondary battery includes a lithium metal battery.

23. An electrical appliance, characterized in that, The electrical device includes the secondary battery as described in any one of claims 20 to 22.

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