Electrode pieces, electrode assemblies, batteries and electrical equipment

Abstract

The present invention relates to a pole piece, an electrode assembly, a battery and an electrical device. A pole piece includes a current collector and an active material layer. The current collector includes a support layer, a conductive layer and an insulating layer. The conductive layer is arranged on the surface of the support layer so that the support layer forms a first exposed area in its width direction, and the insulating layer is arranged in the first exposed area; the active material layer is arranged on the surface of the conductive layer away from the support layer, and the end side of the active material layer and the end side of the conductive layer are respectively in contact with the end side of the insulating layer. An electrode assembly includes a first pole piece, a second pole piece and an insulating member, and the insulating member is sandwiched between the first pole piece and the second pole piece; wherein the first pole piece and / or the second pole piece is the above-mentioned pole piece. A battery includes the above-mentioned electrode assembly. An electrical device includes the above-mentioned battery. The above-mentioned pole piece, electrode assembly, battery and electrical device can improve the ability of the pole piece to resist internal short circuit by arranging the first exposed area in the width direction of the support layer and covering the first exposed area with an insulating layer.

Description

Technical Field

[0001] The present invention relates to the technical field of power batteries, and in particular to a pole piece, an electrode assembly, a battery and an electrical device. Background Art

[0002] With the popularization and promotion of new energy vehicles, the charging and discharging performance and endurance of new energy vehicles have increasingly attracted people's attention and attention. Power batteries are a rechargeable battery that is the power source of new energy vehicles and are widely used in the field of new energy vehicles.

[0003] To meet the structural requirements, the traditional composite current collector can be divided into a coating area and a welding area along the width direction. The coating area is used to carry the active material layer and collect the current generated by the electrochemical reaction of the active material. The welding area connects the multi-layer pole pieces and the pole piece and the top cover together by welding to complete the connection between the pole piece and the battery pole. Ultrasonic welding is usually used to connect the multi-layer pole pieces. Due to the speed difference between the equipment and the current collector, it is easy to cause wear and scratches at the junction of the welding area and the coating area. The conductive layer is also easily damaged or even cracked, causing the pole piece square resistance to increase or even lose its conductivity, and the pole piece's internal short circuit resistance and overcurrent capacity are poor. Summary of the invention

[0004] Based on this, it is necessary to provide a pole piece, an electrode assembly, a battery and an electrical device to address the problem of poor internal short circuit resistance and overcurrent capacity of the pole piece.

[0005] A pole piece includes a current collector and an active material layer, the current collector includes a support layer, a conductive layer and an insulating layer, the conductive layer is arranged on the surface of the support layer so that the support layer forms a first exposed area in its width direction, and the insulating layer is arranged in the first exposed area; the active material layer is arranged on the surface of the conductive layer away from the support layer, and the end side of the active material layer and the end side of the conductive layer are respectively abutted against the end side of the insulating layer. The above-mentioned pole piece can improve the ability of the pole piece to resist internal short circuit by arranging the first exposed area in the width direction of the support layer carrying the conductive layer and covering the first exposed area with an insulating layer; the end side of the active material layer and the end side of the conductive layer are respectively abutted against the end side of the insulating layer, which can further improve the safety performance.

[0006] In some embodiments, the thickness of the conductive layer is D1, the thickness of the insulating layer is D2, the thickness of the active material layer is D3, the ratio A=D2 / (D1+D3), 1.01≤A≤1.05. In this way, by controlling the thickness of the conductive layer, the active material layer and the ratio range of the thickness of the insulating layer, the insulating layer can better protect the conductive layer and the active material layer, while not causing the pole piece itself to occupy too much space in the thickness direction.

[0007] In some embodiments, the thickness D1 of the conductive layer is in the range of 300nm≤D1≤2μm, and the thickness D3 of the active material layer is in the range of 10μm≤D3≤200μm. In this way, the conductive layer plays the role of conducting and collecting current. By controlling the thickness of the conductive layer and the active material layer, the conductive and current collecting performance of the entire electrode can be controlled.

[0008] In some embodiments, the width L2 of the insulating layer is in the range of 0.5 mm ≤ L2 ≤ L1, where L1 is the width of the first exposed area. In this way, by controlling the width range of the insulating layer, the volume energy density of the battery can be ensured while ensuring that the insulating layer is not easily broken to provide insulation protection.

[0009] In some embodiments, the width L1 of the first exposed area is in the range of 1 mm ≤ L1 ≤ 5 mm. In this way, sufficient exposed space can be reserved on the conductive layer to provide insulation, while the overall width of the electrode sheet will not be too wide.

[0010] In some embodiments, the pole piece further includes a metal deposition layer, which is disposed on the end side of the current collector. Thus, by disposing the metal deposition layer on the end side of the current collector, the metal deposition layer is electrically connected to the battery pole, thereby expanding the flow area of ​​the current collector and improving the defect that the conventional pole ear needs to occupy space for electrical connection with the pole after being folded.

[0011] In some embodiments, the thickness of the metal deposition layer is D, 0.5 mm ≤ D ≤ 3 mm. In this way, the metal deposition layer can be electrically connected to the battery pole, while preventing the metal deposition layer from being too thick, thereby increasing the overall thickness of the pole piece.

[0012] In some embodiments, one end of the conductive layer away from the insulating layer is flush with one end of the active material layer away from the insulating layer. In this way, the active material layer completely covers the surface of the conductive layer, and no tab cutting area is reserved on the conductive layer, thereby forming a pole piece without a tab structure.

[0013] In some embodiments, one end of the conductive layer away from the insulating layer exceeds the other end of the active material layer away from the insulating layer in its width direction, so that the conductive layer forms a second exposed area in its width direction. In this way, the active material layer does not completely cover the surface of the conductive layer, and the second exposed area reserved on the conductive layer is the tab cutting area, thereby forming an ultra-short tab-free pole piece, and the structural design is simple and reasonable.

[0014] In some embodiments, the width L of the second exposed area is in the range of 0.5 mm ≤ L ≤ 2 mm. Thus, by controlling the value range of the second exposed area, the overall width of the pole piece can be ensured not to be too wide and occupy space while meeting the requirements for setting the pole lugs.

[0015] An electrode assembly includes a first electrode piece, a second electrode piece and an insulating member, wherein the insulating member is sandwiched between the first electrode piece and the second electrode piece; wherein the first electrode piece and / or the second electrode piece is the above-mentioned electrode piece. The above-mentioned electrode assembly is provided with a first exposed area in the width direction of a support layer carrying a conductive layer, and the first exposed area is covered with an insulating layer, so that the electrode piece has better internal short circuit resistance and overcurrent capacity.

[0016] In some embodiments, the first pole piece and the second pole piece are both the pole pieces described above, and the insulating layers in the first pole piece and the second pole piece are located at opposite ends in the width direction of the insulating member. In this way, during the spraying process of the metal deposition layer, the metal deposition layer particles falling on the insulating layer will not affect the pole piece at the opposite end, thereby avoiding the problem of short circuit in the pole piece caused by the metal deposition layer particles.

[0017] A battery includes the electrode assembly mentioned above. The electrode assembly of the battery mentioned above has good internal short circuit resistance and overcurrent capacity, and the battery has high safety performance in use.

[0018] A battery for an electrical device having good power supply continuity and high safety performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of a vehicle in one embodiment;

[0020] Figure 2 is a schematic diagram of a battery in one embodiment;

[0021] Figure 3 is a schematic diagram of a current collector in one embodiment;

[0022] Figure 4 is a schematic diagram of a pole piece in the first embodiment;

[0023] Figure 5 is a schematic diagram of an electrode assembly in the first embodiment;

[0024] Figure 6 is a schematic diagram of a pole piece in the second embodiment;

[0025] Figure 7 Schematic diagram of the electrode assembly in the second embodiment.

[0026] Reference numerals:

[0027] 10. Vehicle; 11. Controller; 12. Motor; 20. Battery; 21. Housing; 21a. First part; 21b. Second part; 22. Battery cell; 30. Pole piece; 31. First pole piece; 32. Second pole piece; 40. Insulator; 100. Current collector; 110. Support layer; 120. Conductive layer; 130. Insulating layer; 200. Active material layer; 300. Metal deposition layer;

[0028] A1, first exposed area; A2, second exposed area; D1, thickness of conductive layer; D2, thickness of insulating layer; D3, thickness of active material layer; D4, thickness of supporting layer; D, thickness of metal deposition layer; L1, width of first exposed area; L2, width of insulating layer; L, width of second exposed area; X, width direction; Y, thickness direction. DETAILED DESCRIPTION

[0029] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0031] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0032] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0033] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0034] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0035] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0036] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0037] With the popularization and promotion of new energy vehicles, the charging and discharging performance and endurance of new energy vehicles have increasingly attracted people's attention and attention. Power batteries are a rechargeable battery that is the power source of new energy vehicles and are widely used in the field of new energy vehicles.

[0038] To meet the structural requirements, the traditional composite current collector can be divided into a coating area and a welding area along the width direction. The coating area is used to carry the active material layer and collect the current generated by the electrochemical reaction of the active material. The welding area connects the multi-layer pole pieces and the pole piece and the top cover together by welding to complete the connection between the pole piece and the battery pole. Ultrasonic welding is usually used to connect the multi-layer pole pieces. Due to the speed difference between the equipment and the current collector, it is easy to cause wear and scratches at the junction of the welding area and the coating area. The conductive layer is also easily damaged or even cracked, causing the pole piece square resistance to increase or even lose its conductivity, and the pole piece's internal short circuit resistance and overcurrent capacity are poor.

[0039] Based on the above considerations, after in-depth research, a pole piece, an electrode assembly, a battery and an electrical device are designed. The conductive layer is arranged on the surface of the support layer and the support layer forms a first exposed area in its width direction, and the insulating layer is arranged in the first exposed area. The active material layer is arranged on the surface of the conductive layer away from the support layer, and the end side of the active material layer and the end side of the conductive layer respectively abut against the end side of the insulating layer. In this way, by setting the first exposed area in the width direction of the support layer carrying the conductive layer and covering the first exposed area with an insulating layer, the pole piece's ability to resist internal short circuits can be improved; the end side of the active material layer and the end side of the conductive layer respectively abut against the end side of the insulating layer, which can further improve the safety performance.

[0040] The embodiment of the present application provides an electric device using a battery as a power source, and the electric device may be, but is not limited to, a mobile phone, a tablet, a laptop, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft, etc. Among them, the electric toy may include a fixed or mobile electric toy, for example, a game console, an electric car toy, an electric ship toy, an electric airplane toy, etc., and the spacecraft may include an airplane, a rocket, a space shuttle, a spacecraft, etc.

[0041] For the convenience of description, the following embodiments are described by taking a vehicle 10 as an example of an electrical device in an embodiment of the present application.

[0042] Please refer to Figure 1 , Figure 1 A schematic diagram of the structure of a vehicle 10 provided for some embodiments of the present application. The vehicle 10 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 20 is provided inside the vehicle 10, and the battery 20 may be provided at the bottom, head or tail of the vehicle 10. The battery 20 may be used to power the vehicle 10, for example, the battery 20 may be used as an operating power source for the vehicle 10. The vehicle 10 may also include a controller 11 and a motor 12, and the controller 11 is used to control the battery 20 to power the motor 12, for example, for the starting, navigation and working power requirements of the vehicle 10 during driving. In other embodiments of the present application, the battery 20 may not only be used as an operating power source for the vehicle 10, but also as a driving power source for the vehicle 10, replacing or partially replacing fuel or natural gas to provide driving force for the vehicle 10.

[0043] Please refer to Figure 2 , Figure 2An exploded view of a battery 20 provided in some embodiments of the present application. The battery 20 includes a box body 21 and a battery cell 22, and the battery cell 22 is contained in the box body 21. The box body 21 is used to provide a storage space for the battery cell 22, and the box body 21 can adopt a variety of structures. In some embodiments, the box body 21 may include a first part 21a and a second part 21b, the first part 21a and the second part 21b cover each other, and the first part 21a and the second part 21b jointly define a storage space for accommodating the battery cell 22. The second part 21b may be a hollow structure with an opening 23a at one end, the first part 21a may be a plate-like structure, and the first part 21a covers the opening 23a side of the second part 21b, so that the first part 21a and the second part 21b jointly define a storage space; the first part 21a and the second part 21b may also be hollow structures with an opening 23a on one side, and the opening 23a side of the first part 21a covers the opening 23a side of the second part 21b. Of course, the box body 21 formed by the first part 21a and the second part 21b can be in various shapes, such as a cylinder, a cuboid, etc.

[0044] In the battery 20, there can be multiple battery cells 22, and the multiple battery cells 22 can be connected in series, in parallel, or in mixed connection. Mixed connection means that the multiple battery cells 22 are both connected in series and in parallel. The multiple battery cells 22 can be directly connected in series, in parallel, or in mixed connection, and then the whole formed by the multiple battery cells 22 is accommodated in the box 21; of course, the battery 20 can also be a battery 20 module formed by multiple battery cells 22 connected in series, in parallel, or in mixed connection, and the multiple battery 20 modules are then connected in series, in parallel, or in mixed connection to form a whole, and accommodated in the box 21.

[0045] Among them, each battery cell 22 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery or a magnesium-ion battery, but it is not limited to this. The battery cell 22 can be cylindrical, flat, rectangular or other shapes. In the present application, the battery cell 22 can include a lithium-ion secondary battery, a lithium-ion primary battery, a lithium-sulfur battery, a sodium-lithium-ion battery, a sodium-ion battery or a magnesium-ion battery, etc., and the embodiments of the present application are not limited to this. The battery cell 22 can be cylindrical, flat, rectangular or other shapes, etc., and the embodiments of the present application are not limited to this.

[0046] Please refer to Figure 3 and Figure 4The pole piece 30 in one embodiment includes a current collector 100 and an active material layer 200. The current collector 100 includes a support layer 110, a conductive layer 120 and an insulating layer 130. The conductive layer 120 is disposed on the surface of the support layer 110 so that the support layer 110 forms a first exposed area A1 in its width direction. The insulating layer 130 is disposed in the first exposed area A1. The active material layer 200 is disposed on the surface of the conductive layer 120 away from the support layer 110. The end side of the active material layer 200 and the end side of the conductive layer 120 are respectively in contact with the end side of the insulating layer 130.

[0047] Here, the width direction is Figure 3 X direction shown.

[0048] In the present application, the current collector 100 is a component or part that carries active materials and collects and outputs the current generated by the electrode active materials.

[0049] In the present application, the support layer 110 is a component that supports the conductive layer 120 and the insulating layer 130, and the support layer 110 itself has insulating properties. The material of the support layer 110 includes one or more of a polymer material and a polymer-based composite material. The polymer-based composite material includes a polymer material and an additive, and the additive is at least one of an inorganic non-metallic material and a metal material. The thickness D4 of the support layer 110 ranges from 1 μm ≤ D2 ≤ 20 μm, preferably, 2 μm ≤ D4 ≤ 6 μm.

[0050] In the present application, the conductive layer 120 can be formed on the surface of the support layer 110 by at least one of mechanical rolling, bonding, vapor deposition, chemical plating, and electroplating, so that the conductive layer 120 is tightly combined with the support layer 110. The material of the conductive layer 120 is at least one of a metal conductive material and a carbon-based conductive material. The metal conductive material is selected from at least one of aluminum, copper, nickel, titanium, silver, nickel-copper alloy, and aluminum-zirconium alloy, and the carbon-based conductive material is selected from at least one of graphite, acetylene black, graphene, and carbon nanotubes.

[0051] In the present application, the material of the insulating layer 130 is one of an organic polymer insulating material, an inorganic insulating material, and a composite material. Preferably, the composite material is composed of an organic polymer insulating material and an inorganic insulating material.

[0052] In the present application, the active material layer 200 includes active materials, binders, conductive agents and solvents. The above raw materials are mixed and stirred to obtain active slurry, and then the active slurry is coated on the surface of the conductive layer 120 and dried to form an active material layer. The active material includes at least one of lithium nickel cobalt manganese oxide, lithium iron phosphate, lithium nickel oxide, lithium nickel manganese oxide and lithium nickel iron manganese oxide, or carbon materials (graphite, hard carbon, soft carbon, carbon nanotubes, graphene), wherein the graphite includes artificial graphite, natural graphite mesophase carbon microspheres; at least one of lithium titanate, silicon negative electrode, silicon carbon negative electrode, lithium metal negative electrode material, tin-based negative electrode material, and tin oxide negative electrode material. The active material is divided into positive active material and negative active material, that is, the active material slurry of the second pole piece 32 uses positive active material, and the active material slurry of the first pole piece 31 uses negative active material.

[0053] In this embodiment, conductive layers 120 are provided on both sides of the support layer 110 in the thickness direction, and active material layers 200 are provided on the surface of each conductive layer 120 away from the support layer 110. Figure 3 In other embodiments, the conductive layer 120 may be disposed only on one side of the support layer 110 in the thickness direction.

[0054] The above-mentioned pole piece 30 can improve the ability of the pole piece 30 to resist internal short circuit by setting a first exposed area A1 in the width direction of the support layer 110 carrying the conductive layer 120 and covering the insulating layer 130 in the first exposed area A1; the end sides of the active material layer 200 and the end sides of the conductive layer 120 are respectively abutted against the end sides of the insulating layer 130, which can further improve the safety performance.

[0055] According to some embodiments of this application, please refer to Figure 3 and Figure 4 , the thickness of the conductive layer is D1, the thickness of the insulating layer is D2, the thickness of the active material layer is D3, the ratio A=D2 / (D1+D3), 1.01≤A≤1.05.

[0056] It is understandable that when the thickness D2 of the insulating layer is too thin, the end sides of the insulating layer 130 cannot completely cover the end sides of the conductive layer 120 and the active material layer 200, and the conductive layer 120 and the active material layer 200 will be exposed, and there is a risk of being contaminated or damaged by other substances; when the thickness D2 of the insulating layer is too thick, the overall thickness of the electrode 30 is thickened and occupies a large space, which is not conducive to the lightweight and miniaturized design of the product.

[0057] Through the above arrangement, by controlling the ratio range of the thickness D3 of the conductive layer 120 and the active material layer to the thickness D2 of the insulating layer, the insulating layer 130 can provide better protection for the conductive layer 120 and the active material layer 200, while preventing the electrode 30 from occupying too much space in the thickness direction.

[0058] According to some embodiments of this application, please refer to Figure 3 The thickness D1 of the conductive layer is in the range of 0.3 μm ≤ D1 ≤ 2 μm, and the thickness D3 of the active material layer 200 is in the range of 10 μm ≤ D3 ≤ 200 μm.

[0059] Preferably, 0.5 μm ≤ D1 ≤ 1.5 μm.

[0060] Here, the conductive layer 120 plays the role of conducting electricity and collecting current. By controlling the thickness D1 of the conductive layer and the thickness D3 of the active material layer 200 , the overall conductivity and current collecting performance of the electrode sheet 30 can be controlled.

[0061] According to some embodiments of this application, please refer to Figure 4 The width L2 of the insulating layer is in the range of 0.5 mm ≤ L2 ≤ L1, where L1 is the width of the first exposed area.

[0062] It is understandable that if the width L2 of the insulating layer is too small, the insulating layer 130 is very likely to break during the processing of the pole piece 30 and cannot provide good insulation protection; if the width L2 of the insulating layer is too large, the volume energy density of the battery 20 will be reduced.

[0063] Through the above configuration, by controlling the value range of the width L2 of the insulating layer, it is beneficial to ensure the volume energy density of the battery 20 while ensuring that the insulating layer 130 is not easy to break for insulation protection.

[0064] According to some embodiments of this application, please refer to Figure 3 The width L1 of the first exposed area ranges from 1mm≤L1≤5mm.

[0065] It is understandable that if the width L1 of the first exposed area is too small, it cannot meet the requirement of setting the insulating layer 130 in the first exposed area A1; if the width L1 of the first exposed area is too large, the width of the conductive layer 120 is too large, resulting in the pole piece 30 occupying more space in the overall width direction.

[0066] Preferably, 2mm≤L1≤3mm.

[0067] Through the above arrangement, sufficient exposed space can be reserved on the conductive layer 120 to provide insulation, while the overall width of the pole piece 30 will not be too wide.

[0068] According to some embodiments of this application, please refer to Figure 5 The pole piece 30 further includes a metal deposition layer 300 , and the metal deposition layer 300 is disposed on the end side of the current collector 100 .

[0069] Specifically, the metal deposition layer 300 is disposed on both ends of the current collector 100, and the metal deposition layers 300 on the two ends have different electrical polarities. Figure 5 As shown, a metal deposition layer 300 with a positive polarity is provided on one end side of the current collector 100 where the insulating layer 130 is not provided, and a metal deposition layer 300 with a negative polarity is provided on one end side of the current collector 100 where the insulating layer 130 is provided, and electrical connection with the battery 20 pole is achieved through the metal deposition layer 300.

[0070] In the present application, the metal deposition layer 300 needs to have conductive properties, and the metal deposition layer 300 is selected from at least one of aluminum, copper, nickel, titanium, silver, nickel-copper alloy, and aluminum-zirconium alloy.

[0071] Through the above arrangement, by setting a metal deposition layer 300 on the end side of the current collector 100, an electrical connection with the battery 20 pole is achieved through the metal deposition layer 300, the flow area of ​​the current collector 100 is expanded, and the defect that the conventional pole ear needs to occupy space for electrical connection with the pole after being folded is improved.

[0072] According to some embodiments of this application, please refer to Figure 5 , the thickness of the metal deposition layer is D, 0.5mm≤D≤3mm.

[0073] Preferably, 1 mm ≤ D ≤ 2 mm.

[0074] Through the above arrangement, the metal deposition layer 300 can be electrically connected to the pole of the battery 20 , while preventing the metal deposition layer 300 from being too thick, thereby preventing the overall thickness of the pole piece 30 from increasing.

[0075] According to some embodiments of this application, please refer to Figure 5 , one end of the conductive layer 120 away from the insulating layer 130 is flush with one end of the active material layer 200 away from the insulating layer 130 .

[0076] In this embodiment, one end of the conductive layer 120 close to the insulating layer 130 is in contact with the end side of the insulating layer 130, and one end of the conductive layer 120 close to the insulating layer 130 is flush with one end of the active material layer 200 close to the insulating layer 130, so that the active material layer 200 completely covers the surface of the conductive layer 120. The above-mentioned pole piece 30 also includes a pole ear. Since no pole ear cutting area is reserved on the conductive layer 120, a pole piece 30 without a pole ear structure is formed, and a pole ear needs to be provided on the pole piece 30 without a pole ear structure.

[0077] In other embodiments, the end of the conductive layer 120 close to the insulating layer 130 and the end of the active material layer 200 close to the insulating layer 130 may not be flush.

[0078] Through the above arrangement, the active material layer 200 completely covers the surface of the conductive layer 120 , and no tab cutting area is reserved on the conductive layer 120 , thereby forming a pole piece 30 without a tab structure.

[0079] According to some embodiments of this application, please refer to Figure 6 One end of the conductive layer 120 away from the insulating layer 130 exceeds one end of the active material layer 200 away from the insulating layer 130 in its width direction, so that the conductive layer 120 forms a second exposed area A2 in its width direction.

[0080] In this embodiment, one end of the conductive layer 120 close to the insulating layer 130 is in contact with the end side of the insulating layer 130, and one end of the conductive layer 120 close to the insulating layer 130 is flush with one end of the active material layer 200 close to the insulating layer 130, so that the active material layer 200 does not completely cover the surface of the conductive layer 120. The above-mentioned pole piece 30 also includes a pole ear, which can be formed by cutting the second exposed area A2 of the conductive layer 120, thereby forming a pole piece 30 with an ultra-short pole ear structure, without the need to provide a pole ear electrically connected to the conductive layer 120.

[0081] In other embodiments, the end of the conductive layer 120 close to the insulating layer 130 and the end of the active material layer 200 close to the insulating layer 130 may not be flush.

[0082] Through the above arrangement, the active material layer 200 does not completely cover the surface of the conductive layer 120 , and the second exposed area A2 reserved on the conductive layer 120 is the tab cutting area, thereby forming an ultra-short tab-free pole piece 30 , and the structural design is simple and reasonable.

[0083] According to some embodiments of this application, please refer to Figure 6 and Figure 7 The width L of the second exposed area ranges from 0.5 mm ≤ L ≤ 2 mm.

[0084] It is understandable that if the width L of the second exposed area is too wide, the overall width of the electrode sheet 30 will be too wide and occupy space; if the width L of the second exposed area is too narrow, it cannot meet the requirements of the electrode ear setting.

[0085] Through the above configuration, by controlling the value range of the second exposed area A2, it is possible to ensure that the overall width of the pole piece 30 is not too wide to occupy space while meeting the requirements for setting the pole lug.

[0086] Please refer to Figure 5 and Figure 7 The electrode assembly in one embodiment includes a first pole piece 31, a second pole piece 32 and an insulating member 40, wherein the insulating member 40 is sandwiched between the first pole piece 31 and the second pole piece 32. The first pole piece 31 and / or the second pole piece 32 are the pole pieces mentioned above.

[0087] In the present application, the material of the insulating member 40 can be one of an organic polymer insulating material, an inorganic insulating material, and a composite material. Preferably, the composite material is composed of an organic polymer insulating material and an inorganic insulating material. For example, the material of the insulating member 40 is at least one of aluminum oxide, polyvinylidene fluoride, boron carbide, silicon carbide, boron nitride, silicon nitride, boron phosphide, and silicon phosphide. The first pole piece 31 is a negative pole piece, and the second pole piece 32 is a positive pole piece.

[0088] The electrode assembly described above is provided with a first exposed area A1 in the width direction of the support layer 110 carrying the conductive layer 120 and the insulating layer 130 is covered on the first exposed area A1 , so that the electrode piece 30 has better internal short circuit resistance and current carrying capacity.

[0089] According to some embodiments of this application, please refer to Figure 5 The first pole piece 31 and the second pole piece 32 are both the pole pieces mentioned above, and the insulating layers 130 in the first pole piece 31 and the second pole piece 32 are located at opposite ends in the width direction of the insulating member 40 .

[0090] For example, Figure 5 As shown, the first pole piece 31, the insulating member 40, the second pole piece 32, the insulating member 40, and the first pole piece 31 are stacked in sequence, wherein the metal deposition layer 300 at the right end of all the first pole pieces 31 and the second pole pieces 32 is negative polarity, and the metal deposition layer 300 at the left end of all the first pole pieces 31 and the second pole pieces 32 is positive polarity. When the metal deposition layer 300 with negative polarity is applied to the right end of all the first pole pieces 31, the end face of the second pole piece 32 is protected by the insulating layer 130 to prevent the metal deposition layer 300 with negative polarity from contacting with the end face of the second pole piece 32 and causing a short circuit; when the metal deposition layer 300 with positive polarity is applied to the left end of all the second pole pieces 32, the end face of the first pole piece 31 is protected by the insulating layer 130 to prevent the metal deposition layer 300 with positive polarity from contacting with the end face of the first pole piece 31 and causing a short circuit.

[0091] Through the above arrangement, during the spraying process of the metal deposition layer 300, the particles of the metal deposition layer 300 falling on the insulating layer 130 will not affect the pole piece 30 at the opposite end, thereby avoiding the problem of short circuit in the pole piece 30 caused by the particles of the metal deposition layer 300.

[0092] Please refer to Figure 2 , a battery 20 in one embodiment includes the above-mentioned electrode assembly.

[0093] It should be noted that, in addition to the above-mentioned electrode assembly, the battery 20 also includes a shell, an electrolyte and other components, and the electrode assembly and the electrolyte are contained in the shell.

[0094] In the present application, the battery 20 may be a winding type or a stacked type. The battery 20 may be one of a lithium ion secondary battery, a lithium primary battery, a sodium ion battery, and a magnesium ion battery, but is not limited thereto.

[0095] The above-mentioned battery 20 has good internal short circuit resistance and overcurrent capacity of the electrode assembly, and the battery 20 has high safety performance in use.

[0096] Please refer to Figure 1 In one embodiment, the battery 20 of the electric device is used to supply power to the electric device. The electric device has good power supply continuity and high safety performance.

[0097] In order to study the influence of different thickness D of the metal deposition layer 300, thickness ratio A and width L of the second exposed area on the bonding force between the metal deposition layer 300 and the current collector 100, a plurality of comparative experiments are set up to test and compare the peeling force of the metal deposition layer 300. In the comparative experiment, comparative example 1 and embodiments 1-5 are set up, and other structures and experimental conditions in the comparative example and the embodiments are the same, and the preparation process flow of each battery 20 is the same.

[0098] The specific preparation process of the battery 20 is as follows: (1) Select a support layer 110 of a certain thickness, form a conductive layer 120 of a certain thickness on its surface by vacuum evaporation, and reserve a first exposed area A1 that is not vacuum-plated in the width direction of the support layer 110 to form a current collector 100 with a first exposed area A1; (2) Coat the surface of the current collector 100 with an active material layer, and uniformly coat the insulating layer 130 on the first exposed area A1, wherein the pole piece 30 with no tab structure is fully coated without leaving any blank space, and a second exposed area A2 is reserved in the middle of the pole piece 30 with an ultra-short tab structure as designed; (3) Perform gold spraying on the end side of the current collector 100 to form a metal deposition layer 300, and then weld the pins to the metal deposition layer 300 after energization.

[0099] The peeling force test method of the metal deposition layer 300 is as follows: the peeling force of the metal deposition layer 300 is measured using a tensile testing machine. The semi-finished product after gold spraying is subjected to a peeling force test by a 90° peeling method. A yellow glue with a stronger adhesive force is attached to the gold spraying layer, and the sample is peeled at a speed of 5mm / min, and the average peeling force is read. 32 samples were selected for testing, and the mechanical bonding effect of the spray welding was evaluated by the mean and standard deviation of the welding peeling force of the samples. Among them, the calculation formula of the mean and standard deviation of the welding peeling force is as follows:

[0100] The average value of welding peeling force = the sum of the welding peeling force values ​​of 32 samples / 32;

[0101] Standard deviation of welding peel force = [(sum of welding peel force values ​​of each sample - mean welding peel force)2 / 32]1 / 2;

[0102] Before entering the shell, a withstand voltage test (Hitpot test) is performed, and the Hitpot test results of 500ea battery cells 22 are collected. Finally, they are placed in the battery 20 shell, and the electrolyte is injected (EC:EMC volume ratio is 3:7, LiPF6 is 1mol / L), followed by sealing, formation and other processes, and finally a lithium-ion secondary battery 20 is obtained. The design is effective by collecting the DCR values ​​(i.e. DC resistance values) of 500 battery cells 22 and selecting the temperature rise data of 10ea battery cells 22. Among them, the battery cell 22 welding defect rate = the number of defective battery cells 22 with poor welding / 1000*100%.

[0103] Specifically, the comparative experimental data are shown in Table 1 and Table 2 below:

[0104] Table 1

[0105]

[0106] Table 2

[0107]

[0108]

[0109] It can be seen from Tables 1 and 2 above that when the thickness D of the metal deposition layer is 0.2mm, the peeling force at the gold spraying position is 33N / m, which does not meet the actual use requirements. In the later welding process with the top cover, it is easy to cause cold welding, increase DCR, and cause the temperature rise at this position to increase, resulting in failure of the battery cell 22; when the thickness D of the metal deposition layer is greater than 3mm, due to the large amount of gold spraying, the cooling effect of the liquid nitrogen air knife can no longer offset its heat, which may cause the diaphragm to deform, and the gold spraying particles fall into the battery cell electrode 30, resulting in an increase in the hitpot defect ratio of about 50%. Therefore, the thickness D of the metal deposition layer should be controlled between 0.5mm-3.0mm. Furthermore, in order to improve efficiency, ensure welding reliability and effectively control the height of gold spraying, the thickness D of the metal deposition layer is preferably 1mm-2.0mm.

[0110] Table 3

[0111]

[0112] Table 4

[0113] 90° peel force (N / m) HitPot(500ea battery) Example 1 230 100% OK Example 2 236 100% OK Example 3 233 100% OK Comparative Example 1 232 70% OK

[0114] It can be seen from Tables 3 and 4 above that if the thickness D2 of the insulating layer is less than the sum of the thickness D1 of the active material layer 200 and the conductive layer, the particles of the metal deposition layer 300 have a chance to spray onto the opposite electrode 30, resulting in an increase in the Hitpot defect rate; if the thickness of the insulating layer 130 is too thick, it is easy to cause the problem of winding and bulging edges in the cold pressing stage of the previous process, so the thickness of the insulating layer 130 / (thickness of the active material layer 200 + thickness of the conductive layer 120) is controlled to be 1.01~1.05.

[0115] Table 5

[0116]

[0117] Table 6

[0118]

[0119] As can be seen from Tables 5 and 6 above, the design of the ultra-short tab helps to improve the overall peel strength of the metal deposition layer 300, strengthen the bonding site of the metal deposition layer 300 during the gold spraying welding process, and in addition to the end surface, a portion of the surface of the ultra-short tab can be sprayed, which increases the flow area, improves the flow capacity of the pole piece 30, and reduces the temperature rise. The width of the second exposed area A2 should not be too long, otherwise the effect of reducing the folded tab space and the purpose of increasing the volume energy density will not be achieved.

[0120] According to some embodiments of the present application, see Figures 3 to 5 The pole piece 30 in one embodiment includes a current collector 100 and an active material layer 200. The current collector 100 includes a support layer 110, a conductive layer 120, an insulating layer 130 and a metal deposition layer 300. The conductive layer 120 is disposed on the surface of the support layer 110 so that the support layer 110 forms a first exposed area A1 in its width direction. The insulating layer 130 is disposed in the first exposed area A1. The active material layer 200 is disposed on the surface of the conductive layer 120 away from the support layer 110. The end sides of the active material layer 200 and the end sides of the conductive layer 120 are respectively in contact with the end sides of the insulating layer 130. The metal deposition layer 300 is disposed on the end side of the current collector 100.

[0121] See also Figure 4 and Figure 5 , one end of the conductive layer 120 away from the insulating layer 130 is flush with one end of the active material layer 200 away from the insulating layer 130; or, see Figure 6 and Figure 7 The end of the conductive layer 120 away from the insulating layer 130 exceeds the end of the active material layer 200 away from the insulating layer 130 in its own width direction, so that the conductive layer 120 forms a second exposed area A2 in its own width direction, and the width L of the second exposed area ranges from 0.5mm≤L≤2mm.

[0122] Among them, the thickness of the conductive layer 120 is D1, the thickness of the insulating layer 130 is D2, the thickness of the active material layer 200 is D3, the ratio A=D2 / (D1+D3), 1.01≤A≤1.05, 0.3μm≤D1≤2μm, 10μm≤D3≤200μm, the width L2 of the insulating layer 130 is in the range of 0.5mm≤L2≤L1, the width L1 of the first exposed area A1 is in the range of 1mm≤L1≤5mm, and the thickness D of the metal deposition layer 300 is in the range of 0.5mm≤D≤3mm.

[0123] According to some embodiments of the present application, see Figure 5 and Figure 7 In one embodiment, the electrode assembly includes the above-mentioned pole piece 30 and the insulating member 40 , and the insulating member 40 is disposed on the surface of the pole piece 30 .

[0124] According to some embodiments of the present application, see Figure 2 , a battery 20 in one embodiment includes the above-mentioned electrode assembly.

[0125] According to some embodiments of the present application, see Figure 1 , the battery 20 mentioned above for the electrical equipment in one embodiment.

[0126] 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 them; 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 by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A pole piece, characterized in that: include: A current collector (100) comprising a support layer (110), a conductive layer (120) and an insulating layer (130), wherein the conductive layer (120) is arranged on the surface of the support layer (110) and enables the support layer (110) to form a first exposed area in its width direction, and the insulating layer (130) is arranged in the first exposed area; The active material layer (200) is disposed on the surface of the conductive layer (120) away from the support layer (110), and the end sides of the active material layer (200) and the conductive layer (120) are respectively in contact with the end sides of the insulating layer (130).

2. The pole piece according to claim 1, characterized in that: The thickness of the conductive layer (120) is D1, the thickness of the insulating layer (130) is D2, the thickness of the active material layer (200) is D3, the ratio A=D2 / (D1+D3), 1.01≤A≤1.

05.

3. The pole piece according to claim 2, characterized in that: The thickness D1 of the conductive layer (120) is in the range of 0.3 μm≤D1≤2 μm, and the thickness D3 of the active material layer (200) is in the range of 10 μm≤D3≤200 μm.

4. The pole piece according to claim 2, characterized in that: The width L2 of the insulating layer (130) is in the range of 0.5 mm≤L2≤L1, where L1 is the width of the first exposed area.

5. The pole piece according to claim 4, characterized in that: The width L1 of the first exposed area has a value range of 1 mm≤L1≤5 mm.

6. The pole piece according to claim 1, characterized in that: The pole piece further comprises a metal deposition layer (300), and the metal deposition layer (300) is arranged on the end side of the current collector (100).

7. The pole piece according to claim 6, characterized in that: The thickness of the metal deposition layer (300) is D, 0.5 mm≤D≤3 mm.

8. The pole piece according to claim 1, characterized in that: One end of the conductive layer (120) away from the insulating layer (130) is flush with one end of the active material layer (200) away from the insulating layer (130).

9. The pole piece according to claim 1, characterized in that: One end of the conductive layer (120) away from the insulating layer (130) exceeds one end of the active material layer (200) away from the insulating layer (130) in its width direction, so that the conductive layer (120) forms a second exposed area in its width direction.

10. The pole piece according to claim 9, characterized in that: The width L of the second exposed area is in the range of 0.5 mm ≤ L ≤ 2 mm.

11. An electrode assembly, characterized in that: include: a first pole piece (31); a second pole piece (32); An insulating member (40) is sandwiched between the first pole piece (31) and the second pole piece (32); Wherein, the first pole piece (31) and / or the second pole piece (32) is the pole piece according to any one of claims 1 to 10.

12. The electrode assembly according to claim 11, characterized in that: The first pole piece (31) and the second pole piece (32) are both the pole pieces according to any one of claims 1 to 10, and the insulating layers (130) in the first pole piece (31) and the second pole piece (32) are located at opposite ends in the width direction of the insulating member (40).

13. A battery, characterized in that: Comprising the electrode assembly as claimed in claim 12.

14. An electrical device, characterized in that: Comprising the battery of claim 13.

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