WO2024020835A1

WO2024020835A1 - Current collector, electrode sheet, battery, electric device and manufacturing method for electrode sheet

Info

Publication number: WO2024020835A1
Application number: PCT/CN2022/108165
Authority: WO
Inventors: 郭锁刚; 付成华; 常雯; 叶永煌
Original assignee: 宁德时代新能源科技股份有限公司
Priority date: 2022-07-27
Filing date: 2022-07-27
Publication date: 2024-02-01

Abstract

A current collector, an electrode sheet, a battery, an electric device and a manufacturing method for an electrode sheet. The current collector comprises a main body portion (11) and reinforcement protrusions (12). The main body portion (11) is provided with a first surface (101) and a second surface (102) oppositely arranged in the thickness direction of the current collector. The reinforcement protrusions (12) protrude from at least one of the first surface (101) or the second surface (102). In the width direction of the current collector, the width of the outermost reinforcement protrusions (12) is greater than the width of the reinforcement protrusions (12) close to the middle. Arrangement of the reinforcement protrusions (12) can enhance the structural strength of the current collector and reduce the relative volume of the current collector, such that more active material layers (2) can be accommodated, thereby effectively increasing the energy density of a battery cell (10). Moreover, increasing the size of the reinforcement protrusions (12) on the two sides in the width direction can significantly enhance the structural strength at the periphery of the current collector, thereby reducing the risk of current collector peripheral fracture.

Description

Manufacturing methods and technical fields of current collectors, pole pieces, batteries, electrical devices and pole pieces

[0001] This application belongs to the field of battery technology, and in particular relates to a current collector, a pole piece, a battery, a power device and a method for manufacturing the pole piece. Background technique

[0002] As the consumption of natural resources and the destruction of the environment become increasingly serious, there is an increasing interest in devices that can store energy and effectively utilize the stored energy in various fields. Battery cells are systems that can be combined with each other to harness new renewable energy.

[0003] In the field of battery equipment technology, how to improve the energy density of batteries is an important research direction. Application content

[0004] The embodiment of the present application provides a method for manufacturing a current collector, a pole piece, a battery, an electrical device, and a pole piece, which can improve the energy density of the battery.

[0005] A first aspect of the embodiment of the present application provides a current collector, including a body part and a reinforcing protrusion. Along the thickness direction of the current collector, the body part has a first surface and a second surface arranged oppositely. surface; the reinforcing protrusions protrude from at least one of the first surface or the second surface, and in the width direction of the current collector, the width of the outermost reinforcing protrusions is greater than that near the middle The width of the reinforcing protrusion.

[0006] Using the above structure, by setting the reinforcing protrusions, the structural strength of the current collector itself can be enhanced, the thickness requirement of the current collector can be reduced, and the relative volume of the current collector can be reduced while maintaining the structural strength requirements, thereby making the active material layer The capacity of the battery is increased, effectively improving the energy density of the battery cell; secondly, by increasing the size of the reinforcing protrusions on both sides in the width direction, the structural strength at the edge of the current collector can be significantly enhanced and the risk of fracture at the edge of the current collector is reduced.

[0007] In some optional embodiments of the present application, in the width direction, the outermost The edge of the projection of the reinforcing protrusion on the plane perpendicular to the thickness direction coincides with the edge of the projection of the body part on the plane perpendicular to the thickness direction.

[0008] Adopting the above structure, by reinforcing the protruding edge to coincide with the edge of the current collector, firstly, the structural strength at the edge of the current collector can be enhanced and the risk of fracture at the edge of the current collector can be reduced. Secondly, the edge at the upper edge in the width direction can also be reduced. The groove structure reduces the occurrence of powder detachment at the edge after coating the active material layer.

[0009] In some optional implementations of the present application, the reinforcing protrusion includes a first sub-protrusion and a second sub-protrusion, the first sub-protrusion is provided on the first surface, and the second sub-protrusion The sub-protrusions are arranged on the second surface, and the first sub-protrusions and the second sub-protrusions are offset in the thickness direction.

[0010] Using the above structure, by staggering the first sub-protrusions and the second sub-protrusions in the thickness direction, the recessed structure on the surface of the current collector can be arranged more uniformly, and the first sub-protrusions and the second sub-protrusions can be avoided. The alignment setting will lead to obvious local excessive thinness and local excessive thickness after coating of the active material layer, thereby improving the uniformity of the thickness of the active material layer.

[0011] In some optional embodiments of the present application, in the thickness direction, at least one of the first sub-protrusions partially overlaps with the second sub-protrusion.

[0012] Using the above structure, by partially overlapping the first sub-protrusion and the second sub-protrusion in the thickness direction, the current collector has a larger thickness at the portion where the first sub-protrusion and the second sub-protrusion overlap. , can strengthen the structural strength of the current collector in the thickness direction.

In some optional embodiments of the present application, in a group of the first sub-protrusions and the second sub-protrusions that partially overlap in the thickness direction, at least one is connected to one end of the body part The end surface area of is S1, the overlapping area area of the first sub-protrusion and the second sub-protrusion in the thickness direction is S2, S1 and S2 satisfy, 0.001 WS2/S1 W0.9.

[0014] Using the above structure, by limiting the range of S2/S1, it is possible to avoid the first sub-protrusion and the second sub-protrusion from being completely aligned while ensuring the structural strength of the current collector in the thickness direction, resulting in coating activity. The problem of low uniformity of material layer.

[0015] In some optional embodiments of the present application, the reinforcing protrusions are strip structures extending along the length direction of the current collector.

[0016] Using the above structure, by arranging the reinforcing protrusions in a strip shape, the current collection can be effectively strengthened. The structural strength of the body in the length direction.

[0017] In some optional embodiments of the present application, on a plane perpendicular to the thickness direction, the extension direction of at least part of the reinforcing protrusions is inclined relative to the length direction.

[0018] Using the above structure, by setting the angle between the extension direction of the reinforcing protrusion and the length direction, the area of the current collector that strengthens the structural strength is not a single length direction, thereby improving the overall structural strength of the current collector.

[0019] In some optional embodiments of the present application, the angle between the extension direction of at least part of the reinforcing protrusions and the length direction is a, which satisfies 2° W a W 80°.

[0020] Using the above structure, by limiting the range of the angle a between the extension direction and the length direction, on the one hand, the arrangement position of the area that strengthens the structural strength on the current collector can be adjusted according to the extension direction of the reinforcing protrusion. On the other hand, it can Avoid arranging the extension direction of the reinforcing protrusion perpendicularly to the length direction, which will lead to insufficient fracture strength of the current collector.

[0021] In some optional embodiments of the present application, along the extension direction, the extension lengths of at least two of the reinforcing protrusions are different. Using the above structure, by making the lengths of the reinforcing protrusions different in the length direction, the uniformity of the thickness of the active material layer after the current collector is coated with the active material layer can be improved.

[0022] In some optional embodiments of the present application, in the thickness direction, the thickness of the reinforcing protrusion is D1, which satisfies 0.25 ki mWDI W100 ki m.

[0023] Using the above structure, by setting the thickness of the reinforcing protrusions at 0.25 nm to 100 nm, on the one hand, it is possible to ensure that the reinforcing protrusions protrude from the first surface or the second surface, and alleviate the problem caused by the reinforcing protrusions. The size of the current collector is insufficient, which causes the structural strength of the current collector to be insufficient. On the other hand, it can also avoid the reinforcement protrusions being too large in the thickness direction, causing the reinforcement protrusions to break.

[0024] A second aspect of the embodiment of the present application provides a pole piece, including the above-mentioned current collector and an active material layer. The active material layer is coated on the first surface and/or the second surface. The current collector also includes a rupture area recessed in at least one of the first surface or the second surface, and the rupture area is located in the recessed area between the adjacent reinforcing protrusions.

[0025] Using the above structure, by using a current collector with reinforced protrusions, on the one hand, the contact area between the current collector and the active material layer can be effectively increased, which facilitates the attachment and collection of the active material layer. Fluidically, it improves the connection stability, thereby reducing the contact resistance between the current collector and the active material layer. On the other hand, it can effectively increase the capacity of the active material layer of the pole piece and increase the energy density of the pole piece. Secondly, by setting The recessed area can enhance the ability of the pole piece to preserve the electrolyte and improve the performance of the pole piece; thirdly, by setting the rupture area, it can facilitate the expansion of particles within the pole piece, effectively enhance the infiltration ability of the pole piece, and improve the performance of the pole piece. usage performance. A third aspect of the embodiment of the present application provides a battery cell, including a casing and an electrode assembly. The electrode assembly is accommodated in the casing. The electrode assembly includes the above-mentioned pole piece.

[0026] A fourth aspect of the embodiment of the present application provides a battery including a plurality of the above battery cells.

[0027] A fifth aspect of the embodiment of the present application provides an electrical device, including the above-mentioned battery cell, for providing electrical energy.

[0028] A sixth aspect of the embodiment of the present application provides a method for manufacturing a pole piece, including: providing the above-mentioned current collector; coating an active material layer on the first surface and/or the second surface ; Cold pressing the active material layer to press part of the active material layer into the body part to form a rupture area.

[0029] Using the above solution, by cold pressing the active material layer disposed on the first surface and/or the second surface, some particles of the active material layer can be pressed into the body part to form a rupture zone, without the need for additional The additional step optimizes the production process and facilitates rapid prototyping of the rupture zone.

[0030] Compared with related technologies, the manufacturing method of the current collector, pole piece, battery, electrical device and pole piece according to the embodiment of the present application can enhance the structural strength of the current collector itself and reduce the current collector by arranging reinforcing protrusions. The thickness requirement can relatively reduce the volume of the current collector while maintaining the structural strength requirements, thereby increasing the capacity of the active material layer and effectively increasing the energy density of the battery cell; secondly, by reinforcing the convex plates on both sides in the width direction The increased width can ensure the structural strength at the edge of the current collector. Figure description

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some implementations of the present application. way, for those of ordinary skill in the field, it is not With creative effort, other drawings can be obtained based on these drawings.

[0032] Figure 1 is a schematic structural diagram of a vehicle provided by some embodiments of the present application.

[0033] Figure 2 is a schematic structural diagram of a battery provided by some embodiments of the present application.

[0034] Figure 3 is a schematic structural diagram of a battery cell provided by some embodiments of the present application.

[0035] Figure 4 is a schematic cross-sectional structural diagram of an electrode assembly provided by some embodiments of the present application.

[0036] FIG. 5 is a schematic top view of the current collector provided by some embodiments of the present application.

[0037] Figure 6 is a schematic cross-sectional structural diagram of a pole piece provided by some embodiments of the present application.

[0038] FIG. 7 is a partial structural diagram of a current collector provided by some embodiments of the present application.

[0039] FIG. 8 is a partial structural schematic diagram of a current collector provided by other embodiments of the present application.

[0040] FIG. 9 is a schematic projection view of the first sub-protrusion and the second sub-protrusion on a plane perpendicular to the thickness direction provided by some embodiments of the present application.

[0041] FIG. 10 is a schematic structural diagram of a current collector provided by other embodiments of the present application.

[0042] Figure 11 is a partial structural schematic diagram of the current collector after cold pressing provided by some embodiments of the present application.

[0043] Figure 12 is a schematic diagram of the structure of the rupture area provided by some embodiments of the present application.

[0044] Figure 13 is a schematic flow diagram of a manufacturing method provided by some embodiments of the present application.

In the accompanying drawing:

[0046] 1000. Vehicle; 100. Battery; 200. Controller; 300. Motor; 1 10. Box;

1 11. The first box part; 1 12. The second box part; 120. Shell; 121. End cover; 122. Shell; 130. Electrode assembly; 131. Positive electrode piece; 132. Negative electrode piece; 133. Separator; [0047] 10. Battery cell; 1 1. Body part; 101. First surface; 102. Second surface;

12. Strengthening protrusion; 1201. First sub-protrusion; 1202. Second sub-protrusion; 13. Fracture area; 2. Active material layer. Detailed ways

[0048] The implementation of the technical solution of the present application will be described in detail below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and therefore are only used as examples and cannot be used to limit the scope of protection of the present application.

Unless otherwise defined, all technical and scientific terms used herein are The meanings generally understood by those skilled in the art are the same; the terms used in this article are only for the purpose of describing specific embodiments and are not intended to limit this application; in the description and claims of this application and the above description of the drawings The terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion.

In the description of the embodiments of this 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 indicated technical features. Quantity, specific order, or priority relationship.

[0051] Reference to "embodiments" herein means that specific features, structures or characteristics described in connection with the embodiments may be included in at least one embodiment of the present application. The appearances of this phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are independent or alternative embodiments mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the implementations described herein can be combined with other implementations.

[0052] In the description of the embodiments of this application, the term "and/or" is only an association relationship describing associated objects, indicating that there can be three relationships, such as A and/or B, which can mean: A alone exists, There are three situations: A and B exist at the same time, and B exists alone. In addition, the character "/" in this article generally indicates that the related objects are an "or" relationship.

[0053] In the description of the embodiments of this application, the term "multiple" refers to more than two (including two), and similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple groups" refers to more than two groups (including two groups). "Piece" refers to two or more pieces (including two pieces).

In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left" and "right" The directions or positional relationships indicated by “vertical”, “horizontal”, “top”, “bottom”, “inner”, “outer”, “clockwise”, “counterclockwise”, “axial”, “radial” and “circumferential” are based on the drawings The orientation or positional relationship shown is only to facilitate the description of the embodiments of the present application and simplify the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as Limitations on the implementation of this application.

[0055] In the description of the embodiments of this application, unless otherwise explicitly stipulated and limited, technical terms such as "installation", "connection", "connection" and "fixing" should be understood in a broad sense. For example, it can be a fixed connection, or a fixed connection. It can be detachably connected, or integrated; it can also be mechanically connected, or It can be an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be an internal connection between two components or an interaction between two components. 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 specific circumstances.

[0056] In the development of battery technology, it is necessary to consider various design factors at the same time, such as cycle life, battery safety and other issues. Among them, energy density has become one of the obstacles restricting the further promotion of batteries.

[0057] The inventor has noticed that the current collector is usually arranged in a sheet-like structure to form a first surface and/or a second surface for coating active materials, resulting in that the structural strength of the current collector is mainly determined by the own strength of the material used. Decision, and the sheet-like structure of the current collector also leads to the problem of large differences in structural strength of various parts of the current collector. For example, the structural strength at the edge of the current collector is lower than that at other positions. Therefore, in order to ensure the structural strength of the current collector, in related technologies, the thickness of the current collector is usually limited to make the current collector thicker, resulting in a larger volume of the current collector, occupying the installation volume of the active material layer, and affecting the battery. capacity increase. And because the current collector is usually a conductive metal material such as copper foil or aluminum foil, which has a high density, its thickness change has a greater impact on the weight of the resulting pole piece, seriously affecting the energy density of the battery. In order to alleviate the technical problem of poor energy density of the battery, the inventor found that by adjusting the structure of the current collector, the overall volume of the current collector can be reduced while maintaining the structural strength requirements, especially the edge strength, and the active material layer can be improved. carrying capacity, thereby increasing the energy density of the battery cells. Specifically, the inventor provides a current collector, including a body part and a reinforcing protrusion. The body part is along the thickness direction of the current collector. The body part has a first surface and a second surface arranged oppositely; the reinforcing protrusion, Protruding from at least one of the first surface or the second surface, in the width direction of the current collector, the width of the outermost reinforcing protrusion is greater than that of the reinforcing protrusion near the middle. width. The setting of reinforcing protrusions can enhance the overall strength of the current collector. That is to say, when the same overall strength of the current collector is met, this solution can reduce the thickness of the main body of the current collector, so that the equivalent thickness and overall volume of the current collector are obtained. decrease. [0058] More systematically, after in-depth research, the inventor of the present application designed a method for manufacturing a current collector, a pole piece, a battery, an electrical device, and a pole piece.

[0059] The embodiment of the present application provides an electrical device that uses a battery as a power source. The electrical device can be, but is not limited to, a mobile phone, a tablet, a laptop, an electric toy, an electric tool, a battery car, Electric cars, ships, spacecraft and more. Among them, electric toys can include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, spaceships, etc.

[0060] In the following embodiments, for convenience of explanation, an electrical device according to an embodiment of the present application is a vehicle 1000 as an example.

[0061] As shown in Figure 1, Figure 1 is a schematic structural diagram of a vehicle 1000 provided by some embodiments of the present application. The vehicle 1000 can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended range vehicle, etc. The vehicle 1000 is equipped with a battery 100 inside, and the battery 100 can be installed at the bottom, head, or tail of the vehicle 1000. The battery 100 can be used to power the vehicle 1000. For example, the battery 100 can be used as an operating power supply for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to provide power to the motor 300, for example, to meet the working power requirements for starting, navigation and driving of the vehicle 1000.

[0062] In some embodiments of the present application, the battery 100 can not only be used as an operating power source for the vehicle 1000, but also can be used as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0063] In the embodiments of this application, the battery mentioned refers to a single physical module including one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in this application may include a battery module or a battery pack.

[0064] As shown in Figure 2, Figure 2 is a schematic structural diagram of a battery 100 provided by some embodiments of the present application. In some embodiments of the present application, the battery 100 includes a box 1 10. The box 1 10 may include a connected first box part 1 1 1 and a second box part 1 12. Multiple battery cells are connected in parallel or The series or mixed combination is placed in the space formed by connecting the first box part 1 11 and the second box part 1 12. The shapes of the first box part 1 1 1 and the second box part 1 12 can be based on The shape formed by combining multiple battery cells is determined. The battery cell may be in the shape of a cylinder, a flat body, a rectangular parallelepiped or other shapes, which are not limited in the embodiments of the present application. The packaging methods of the battery cells include but are not limited to cylindrical battery cells, rectangular battery cells, soft-pack battery cells, etc., which are not specifically limited in the embodiments of the present application. In addition, the battery 100 may also include other structures, such as bus components, for realizing electrical connections between multiple battery cells, which will not be described again here. [0065] As shown in Figure 3, Figure 3 is a schematic structural diagram of a battery cell 10 provided by some embodiments of the present application. In some embodiments of the present application, a battery cell 10 is provided, including a casing 120 and an electrode assembly 130.

[0066] The casing 120 is a component used to form the internal environment of the battery cell. The formed internal environment can be used to accommodate the electrode assembly 130, the electrolyte (not shown in the figure) and other components. The shell 120 can be in various structural forms, such as rectangular parallelepiped, cylinder, etc. For example, the shape of the housing 120 can be determined according to the specific shape of the electrode assembly 130. The outer casing 120 can be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. This embodiment of the present application does not impose any special restrictions on this.

[0067] Figure 4 is a schematic cross-sectional structural diagram of an electrode assembly provided by some embodiments of the present application. Referring to Figure 4, the electrode assembly 130 refers to the assembly used for electrochemical reactions in the battery cell. For example, the electrode assembly 130 is mainly formed by winding or stacking a positive electrode piece 131 and a negative electrode piece 132, and a separator 133 is usually provided between the positive electrode piece 131 and the negative electrode piece 132. The portions of the positive electrode piece 131 and the negative electrode piece 132 that contain active material constitute the main body of the electrode assembly 130, and the portions of the positive electrode piece 131 and the negative electrode piece 132 that do not contain active material constitute pole tabs respectively. During the charging and discharging process of the battery, the positive active material and negative active material react with the electrolyte.

[0068] Optionally, the housing 120 may include a housing 122 and an end cover 121. The housing 122 is a hollow structure with one side open, and the end cover 121 covers the opening of the housing 122 and forms a sealed connection to form a in a sealed space containing the electrode assembly 130 and the electrolyte.

[0069] Optionally, the housing 120 can also be of other structures. For example, the housing 120 includes a housing 122 and two end caps 121. The housing 122 is a hollow structure with openings on opposite sides, and one end cap 121 corresponds to Covering an opening of the housing 122 and forming a sealed connection to form a sealed space for accommodating the electrode assembly 130 and the electrolyte. Optionally, the housing 120 may contain one or more electrode assemblies 130o

[0070] FIG. 5 is a schematic top structural view of a current collector provided by some embodiments of the present application. Figure 6 is a schematic cross-sectional structural diagram of a pole piece provided by some embodiments of the present application. Figure 7 is a partial structural diagram of a current collector provided by some embodiments of the present application. As shown in Figures 5 to 7, in some embodiments of the present application, a current collector is provided, including a body portion 1 1 and a reinforcing protrusion 12, along the thickness direction of the current collector (the x-axis in Figures 6 and 7 direction), the body portion 1 1 has a first relatively disposed surface 101 and the second surface 102; the reinforcing protrusion 12 protrudes from at least one of the first surface 101 or the second surface 102, in the width direction of the current collector (the z-axis direction in Figures 5 to 7), and the maximum The width of the outer reinforcing protrusions 12 is greater than the width of the reinforcing protrusions 12 near the middle.

[0071] The first surface 101 and the second surface 102 are surfaces used for coating active material on the body part 11 to form the active material layer 2. The first surface 101 and the second surface 102 are two surfaces opposite to each other in the thickness direction of the current collector.

[0072] The reinforcing protrusions 12 are used to strengthen the structural strength on the first surface 101 and/or the second surface 102. For example, a plurality of reinforcing protrusions 12 may be provided on the first surface 101 and/or the second surface 102, and the reinforcing protrusions 12 are strip structures extending along straight lines. For example, the reinforcing protrusions 12 may also be cylindrical protrusions or wavy strip structures.

[0073] By arranging the reinforcing protrusions 12, the structural strength of the current collector itself can be enhanced, the thickness requirement of the current collector can be reduced, and the relative volume of the current collector can be reduced while maintaining the structural strength requirements, thereby allowing the active material layer 2 to accommodate The amount is increased, effectively improving the energy density of the battery cell; secondly, by increasing the width of the reinforcing protrusions 12 on both sides in the width direction, the structural strength at the edge of the current collector can be ensured.

[0074] In a preferred embodiment of the present invention, both the first surface 101 and the second surface 102 can be provided with a plurality of reinforcing protrusions 12. In the thickness direction of the current collector (x-axis direction in Figures 6 and 7), the reinforcing protrusions 12 on the first surface 101 and the second surface 102 can be aligned.

[0075] In a preferred embodiment of the present invention, depending on the type of coating material, the current collector can be applied to the positive electrode piece or the negative electrode piece. In a preferred embodiment of the present invention, the body part 1 1 and the reinforcing protrusions 12 can be integrally formed or formed separately. When the main body part 1 1 and the reinforcing protrusions 12 are formed separately, they can be bonded, welded, etc. connected. In a preferred embodiment of the present invention, the material of the current collector can be copper, copper, aluminum, etc.

As shown in Figure 5, in some optional embodiments of the present application, in the width direction (z-axis direction in Figure 5), the projection of the outermost reinforcing protrusion 12 on a plane perpendicular to the thickness direction The edge coincides with the edge of the projection of the main body 11 on a plane perpendicular to the thickness direction.

[0077] On a plane perpendicular to the thickness direction, the edge of the projection of the reinforcing protrusion 12 coincides with the edge of the projection of the current collector, which means that in the width direction, the upper edge of the reinforcing protrusion 12 located above the current collector coincides with The upper edges of the current collector coincide with each other, and the reinforcing protrusions 12 located above the current collector The lower edge coincides with the lower edge of the current collector, so that the thickness of the upper edge in the width direction is one of the thickest parts of the current collector, reducing the semi-open groove-like structure at the edge.

[0078] By reinforcing the edge of the protrusion 12 to coincide with the edge of the current collector, the structural strength at the edge is improved, the groove structure at the edge in the width direction is reduced, and the appearance of powder at the edge after coating the active material layer 2 is reduced. A situation of disengagement.

[0079] FIG. 8 is a partial structural diagram of a current collector provided by other embodiments of the present application. As shown in Figures 5 to 8, in some optional embodiments of the present application, the reinforcing protrusion 12 includes a first sub-protrusion 1201 and a second sub-protrusion 1202, and the first sub-protrusion 1201 is provided on the first surface 101 , the second sub-protrusion 1202 is provided on the second surface 102, and in the thickness direction, the first sub-protrusion 1201 and the second sub-protrusion 1202 are disposed in a staggered manner.

[0080] In the width direction, the first sub-protrusion 1201 includes a first edge 1201 a and a second edge 1201 b, the second sub-protrusion 1202 includes a first edge 1202a and a second edge 1202b, the first sub-protrusion 1201 and the second sub-protrusion 1202 are dislocated, which means that in the thickness direction (x-axis direction in Figure 8), the first edge 1201 a and the first edge 1201 b, or the second edge 1202a and the second edge 1202b , there is at least one set of misaligned settings.

[0081] By staggering the first sub-protrusion 1201 and the second sub-protrusion 1202 in the thickness direction, the recessed structure on the current collector surface can be arranged more uniformly, and the first sub-protrusion 1201 and the second sub-protrusion can be avoided. The alignment setting of 1202 results in obvious partial thinning and partial excessive thickness after coating the active material layer 2, which improves the uniformity of the thickness of the active material layer 2.

[0082] Optionally, in the thickness direction, the first sub-protrusion 1201 may correspond to the area between the two second sub-protrusions 1202. Optionally, the first sub-protrusion 1201 may at least partially overlap the second sub-protrusion 1202 in the thickness direction.

[0083] As shown in Figure 8, in some optional implementations of the present application, in the thickness direction (x-axis direction in Figure 8), at least one first sub-protrusion 1201 partially overlaps with the second sub-protrusion 1202.

[0084] In the thickness direction, at least one of the first sub-protrusions 1201 partially overlaps with the second sub-protrusion 1202 means that, in the thickness direction, the first edge 1201 a or the second edge 1201 b One may be aligned with the area between the first edge 1202a and the second edge 1202b.

[0085] By partially overlapping the first sub-protrusion 1201 and the second sub-protrusion 1202 in the thickness direction, the overlapping portion of the first sub-protrusion 1201 and the second sub-protrusion 1202 on the current collector has a larger Thickness can enhance the structural strength of the current collector in the thickness direction.

[0086] FIG. 9 is a schematic projection view of the first sub-protrusion 1201 and the second sub-protrusion 1202 on a plane perpendicular to the thickness direction provided by some embodiments of the present application. As shown in Figure 9, in some optional embodiments of the present application, among a set of first sub-protrusions 1201 and second sub-protrusions 1202 that partially overlap in the thickness direction, at least one of them is connected to one end of the body part 11 The end area of Stacked part), S1 and S2 satisfy, 0. 001 WS2/S1 WO. 9o

[0087] By limiting S2/S1, it is possible to prevent the first sub-protrusion 1201 and the second sub-protrusion from being completely aligned while ensuring the structural strength of the current collector in the thickness direction, resulting in a uniform coating of the active material layer 2 A low-level problem.

[0088] Optionally, the overlapping first sub-protrusion 1201 or the second sub-protrusion 1202 is close to the body part

The end surface area of one end of 1 1 is S1, and the overlapping area area of the first sub-protrusion 1201 and the second sub-protrusion 1202 is S2. To satisfy the requirement, S2/S1 can be 0. 005, 0. 01, 0. 05, 0. 1, 0. 2, 0. 3, 0. 4, 0. 5, 0. 6, 0. 7 or 0. 8 _O

[0089] As shown in Figure 5, in some optional embodiments of the present application, the reinforcing protrusions 12 are strip structures extending along the length direction of the current collector. By arranging the reinforcing protrusions 12 in a strip shape, the structural strength of the current collector in the length direction (y-axis direction in Figure 5) can be effectively strengthened.

[0090] Alternatively, the cross-section of the reinforcing protrusion 12 can be a rectangular strip structure, the cross-section shape of the reinforcing protrusion 12 can also be a trapezoidal structure, and of the two parallel sides of the trapezoid, the longer one is with the body. Part 1 1 is connected.

[0091] FIG. 10 is a schematic structural diagram of a current collector provided by other embodiments of the present application. As shown in Figure 10, in some optional embodiments of the present application, on a plane perpendicular to the thickness direction (Z-axis direction in Figure 10), at least part of the extension direction of the reinforcing protrusion 12 is relative to the length direction (Z-axis direction in Figure 10). y-axis direction) tilt setting. The extension direction refers to the extension direction of the reinforcing protrusion 12 perpendicular to the thickness direction of the current collector. By setting the angle between the extension direction and the length direction of the reinforcing protrusion 12, the area on the current collector that strengthens the structural strength can be located not in a single length direction, thereby improving the overall structural strength of the current collector.

As shown in Figure 10, in some optional embodiments of the present application, at least partially strengthen the convex The angle between the extension direction of 12 and the length direction (y-axis direction in Figure 10) is a, which satisfies, 2° W a W80° o By limiting the angle a between the extension direction and the length direction, on the one hand, it is possible to strengthen the bulge according to The extension direction of 12 adjusts the location of the area on the current collector that enhances the structural strength. On the other hand, it is possible to avoid the extension direction of the reinforcement protrusion 12 being perpendicular to the length direction, resulting in insufficient fracture strength of the current collector.

[0093] Alternatively, the extending directions of the plurality of reinforcing protrusions 12 can be arranged in parallel.

[0094] Optionally, the angle between the extension direction and the length direction of at least part of the reinforcing protrusion 12 is a. If satisfied, a can be 5°, 120°, 30°, 40°, 50°, 60° or 70°. .

[0095] In some optional embodiments of the present application, along the extension direction, the extension lengths of at least two reinforcing protrusions 12 are different.

[0096] Optionally, in the length direction, multiple reinforcing protrusions 12 can be arranged at intervals along the same straight line.

[0097] As shown in Figure 8, in some optional embodiments of the present application, in the thickness direction (x-axis direction in Figure 8), the thickness of the reinforcing protrusion 12 is D1, which satisfies, 0.25 nmWD1W100nm . The thickness of the reinforcing protrusion 12 is D1, which is the dimension of the reinforcing protrusion 12 from the end connected to the body part 11 to the end far away from the body part 11. By setting the thickness of the reinforcing protrusions 12 to 0.25 nm to 100 mn, on the one hand, it is possible to ensure that the reinforcing protrusions 12 protrude from the first surface 101 or the second surface 102, thereby alleviating the problem caused by the size of the reinforcing protrusions 12. If it is not enough, the structural strength of the current collector cannot be reached. On the other hand, it can also avoid the situation where the reinforcing protrusions 12 are too large in the thickness direction, causing the reinforcing protrusions 12 to break.

[0098] Optionally, in the thickness direction, the thickness of the reinforcing protrusion 12 is D1, which satisfies that D1 can be

70m, 80m or 90m.

[0099] Figure 11 is a partial structural schematic diagram of the current collector after cold pressing provided by some embodiments of the present application. Figure 12 is a schematic structural diagram of the rupture zone 13 provided by some embodiments of the present application. As shown in Figure 1 1 and Figure 12, in some optional embodiments of the present application, a pole piece is provided, including the above-mentioned current collector and an active material layer 2o. The active material layer 2 is coated on the first surface 101 and/or on the second surface 102 . The current collector also includes a rupture area 13 recessed in at least one of the first surface 101 or the second surface 102 , and the rupture area 13 is located in the recessed area between adjacent reinforcing protrusions 12 . [00100] By using a current collector with reinforced protrusions, on the one hand, the contact area between the current collector and the active material layer 2 can be effectively increased, which facilitates the attachment of the active material layer 2 to the current collector and improves the connection stability. Thereby reducing the contact resistance between the current collector and the active material layer 2, on the other hand, it can effectively increase the capacity of the active material layer 2 of the pole piece and improve the energy density of the pole piece. Secondly, by setting the recessed area, the pole piece can be enhanced. The plate's ability to preserve the electrolyte improves the performance of the pole piece; thirdly, by setting the rupture zone 13, it can facilitate the expansion of particles within the pole piece, effectively enhance the infiltration ability of the pole piece, and improve the performance of the pole piece.

[00101] As shown in Figures 11 and 12, in some optional embodiments of the present application, in the plane perpendicular to the thickness direction, the area of the rupture area 13 is S3, and the area of the depressed area is S4, satisfying, 0 . 1 WS3/S4W0. 9. When the number of depression areas is set to be multiple, S4 is the sum of the areas of multiple depression areas. When the number of rupture areas 13 is set to be multiple, S4 is the sum of the areas of multiple rupture areas 13. By limiting S3/S4, on the one hand, it can ensure that the area of the rupture zone 13 is small to avoid affecting the structural strength of the pole piece. On the other hand, it can ensure the area ratio of the rupture zone 13 and effectively improve the strength of the pole piece. Infiltration ability.

[00102] Optionally, in the plane perpendicular to the thickness direction, the area of the rupture area 13 is S3, and the area of the depressed area is S4. To satisfy the requirement, S3/S4 can be 0.2, 0.3, 0.4, 0. 5, 0. 6, 0. 7 or 0. 8 _O

[00103] In some optional embodiments of the present application, a battery cell is provided, including a casing and an electrode assembly. The electrode assembly is accommodated in the casing, and the electrode assembly includes the above-mentioned pole piece.

[00104] In some optional embodiments of the present application, a battery is provided, including a plurality of the above battery cells.

[00105] In some optional embodiments of the present application, an electrical device is provided, including the above-mentioned battery cell, for providing electrical energy.

[00106] Figure 13 is a schematic flow chart of a manufacturing method provided by some embodiments of the present application. As shown in Figure 13, in some optional embodiments of the present application, a method for manufacturing a pole piece is provided, including: S100, providing the above current collector; S200, coating the active material layer 2 on the first surface 101 and /or on the second surface 102; S300, cold-press the active material layer 2 to press part of the active material layer 2 into the body part 1 1 to form a rupture area 13o

[00107] On the activity coated on the first surface 101 and/or the second surface 102 of the body part 1 1 After the material layer 2 is cold-pressed, the particles of the active material layer 2 can be squeezed against the first surface 101 and/or the second surface 102, so that the particles of the active material layer 2 can cause certain damage to the body part 11. Or damaged, thereby forming a rupture area 13o on the body part 11

[00108] By cold pressing the active material layer 2 disposed on the first surface 101 and/or the second surface 102, some particles of the active material layer 2 can be pressed into the body part 11 to form a rupture area 13. Additional steps need to be added to optimize the production process to facilitate rapid prototyping of the rupture zone 13. [00109] Alternatively, the rupture area 13 formed on the body part 11 may be a crack or a groove.

[00110] Optionally, depending on the material of the current collector, the molding method of the current collector is also different. For example, when the material of the current collector is copper, the current collector can be made by methods such as electrolysis or corrosion, so that it can be formed on the body part 1 A reinforced protrusion 12 is formed on one side of 1; when the current collector is made of aluminum, the current collector can be made by electrolysis or corrosion. Since the current collector made of aluminum has a soft texture, the current collector can also be made of Che Kun. Made by pressing or stamping.

[00111] In some optional embodiments of the present application, a current collector is provided, including a body part 11 and a reinforcing protrusion 12. The body part 11 is along the thickness direction of the current collector, and the body part 11 has oppositely arranged The first surface 101 and the second surface 102; the reinforcing protrusions 12 protrude from at least one of the first surface 101 or the second surface 102. In the width direction of the current collector, the width of the reinforcing protrusions 12 on both sides is greater than The middle reinforcement bulge is 12 in width. In the width direction, the edges of the reinforcing protrusions 12 on both sides projected on the plane perpendicular to the thickness direction coincide with the edges of the current collector projected on the plane perpendicular to the thickness direction. The reinforcing protrusion 12 includes a first sub-protrusion 1201 and a second sub-protrusion 1202. The first sub-protrusion 1201 is provided on the first surface 101, and the second sub-protrusion 1202 is provided on the second surface 102. In the thickness direction, The first sub-protrusion 1201 and the second sub-protrusion 1202 are arranged in a staggered position. In the thickness direction, at least one of the first sub-protrusions 1201 partially overlaps the second sub-protrusion 1202. The area of the end face of the overlapping first sub-protrusion 1201 or the second sub-protrusion 1202 close to the body part 11 is S1, and the area of the overlapping area of the first sub-protrusion 1201 and the second sub-protrusion 1202 is S2, which satisfies, 0 . 5WS2/S1 W0. 6. The reinforcing protrusions 12 are strip structures extending along the length direction of the current collector. On a plane perpendicular to the thickness direction, at least part of the extension direction and the length direction of the reinforcing protrusions 12 are arranged obliquely. The angle between the extension direction of at least part of the reinforcing protrusions 12 and the length direction is a, which satisfies, 2° W a W80° o In the width direction, the width of the reinforcing protrusions 12 is different. In the length direction, the reinforcing protrusions 12 are Lengths vary. In the thickness direction, the thickness of the reinforcing protrusion 12 is D1, met, 45 ki mWDI W55 pm.

[00112] Compared with related technologies, the manufacturing method of the current collector, pole piece, battery, electrical device and pole piece in the embodiment of the present application can enhance the structural strength of the current collector itself and reduce the current collector by setting the reinforcing protrusions 12. The thickness requirement of the fluid, while maintaining the structural strength requirements, relatively reduces the volume of the current collector, thereby increasing the capacity of the active material layer 2, effectively increasing the energy density of the battery cell; secondly, by moving the two sides in the width direction The increased width of the reinforcing protrusions 12 can ensure the structural strength at the edge of the current collector.

Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced by equivalents without departing from the scope of the present application, in particular, as long as no There are structural conflicts, and the technical features mentioned in each embodiment can be combined in any way. This application is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

claims

1. A current collector, including: a body part, along the thickness direction of the current collector, the body part having a first surface and a second surface arranged oppositely; a reinforcing protrusion protruding from the first surface or In at least one of the second surfaces, in the width direction of the current collector, the width of the outermost reinforcing protrusion is greater than the width of the reinforcing protrusion near the middle.

2. The current collector according to claim 1, wherein in the width direction, the edge of the projection of the outermost reinforcing protrusion on a plane perpendicular to the thickness direction is perpendicular to the body portion. The edges of the projections on the plane in the thickness direction coincide with each other.

3. The current collector according to claim 1 or 2, wherein the reinforcing protrusion includes a first sub-protrusion and a second sub-protrusion, and the first sub-protrusion is provided on the first surface, so The second sub-protrusion is provided on the second surface, and the first sub-protrusion and the second sub-protrusion are offset in the thickness direction.

4. The current collector according to claim 3, wherein in the thickness direction, at least one of the first sub-protrusions partially overlaps the second sub-protrusions.

5. The current collector according to claim 4, wherein at least one of the first sub-protrusions and the second sub-protrusions partially overlapping in the thickness direction is connected to the body. The end surface area of one end of the portion is S1, and the overlapping area area of the first sub-protrusion and the second sub-protrusion in the thickness direction is S2. S1 and S2 satisfy, 0.001 WS2/S1 W0.9 .

6. The current collector according to any one of claims 1 to 5, wherein the reinforcing protrusion is a strip structure extending along the length direction of the current collector.

7. The current collector according to claim 6, wherein, on a plane perpendicular to the thickness direction, at least part of the extension direction of the reinforcing protrusion is arranged obliquely with respect to the length direction.

8. The current collector according to claim 7, wherein the angle between the extension direction of at least part of the reinforcing protrusions and the length direction is a, which satisfies 2° W a W80°.

9. The current collector according to claim 7 or 8, wherein the extension lengths of at least two of the reinforcing protrusions are different along the extension direction.

10. The current collector according to any one of claims 1 to 9, wherein in the thickness direction, the thickness of the reinforcing protrusion is D1, which satisfies 0.25 ki mWDI W100 ki m.

1 1. A pole piece, comprising: the current collector according to any one of claims 1 to 10; and an active material layer coated on the first surface and/or the second surface; wherein, The current collector further includes a rupture area recessed in at least one of the first surface or the second surface, and the rupture area is located in the recessed area between adjacent reinforcing protrusions.

12. A battery cell, including: a casing; and an electrode assembly, housed in the casing, the electrode assembly including the pole piece as claimed in claim 11.

13. A battery including a plurality of battery cells as claimed in claim 12.

14. An electrical device, including the battery cell according to claim 12, for providing electrical energy.

15. A method of manufacturing a pole piece, comprising: providing the current collector according to any one of claims 1 to 10; coating an active material layer on the first surface and/or the second surface; Cold pressing the active material layer to press part of the active material layer into the body part A rupture zone is formed.

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