Battery cell, battery device, electric equipment and manufacturing method of battery cell

Abstract

The present application relates to a battery cell, a battery device, an electrical device and a method for manufacturing a battery cell. The battery cell includes a pole piece, and the pole piece includes a current collector and an active material layer. Along the thickness direction of the current collector, the current collector has a first surface and a second surface arranged opposite to each other, and an active material layer is provided on at least one of the first surface and the second surface. The active material layer includes a main body and an edge portion, and the edge portion is located on opposite sides of the main body along the width direction of the pole piece. The maximum thickness of the edge portion is less than the minimum thickness of the main body, and the surface of the side of the edge portion facing away from the current collector is constructed as a planar structure. By using a relatively flat edge portion, the quality rate and consistency level of the pole piece can be effectively improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery cell, a battery device, an electrical device, and a method for manufacturing a battery cell. Background Art

[0002] In related technologies, solid-state batteries are usually subjected to isostatic pressing. The specific process of isostatic pressing is as follows: the solid-state battery is placed in a closed container filled with a pressurized medium, and a boosting system is used to apply a certain pressure to the solid-state battery. In this way, the densification of the solid-state battery can be improved.

[0003] However, the quality rate of the electrode in the related art is low. Summary of the Invention

[0004] Based on this, it is necessary to provide a battery cell, a battery device, an electrical device and a method for manufacturing a battery cell in order to improve the quality rate of the electrode.

[0005] According to a first aspect of the present application, a battery cell is provided, comprising a pole piece, the pole piece comprising a current collector and an active material layer. Along the thickness direction of the current collector, the current collector has a first surface and a second surface disposed opposite to each other, and an active material layer is provided on at least one of the first surface and the second surface. The active material layer comprises a main body portion and an edge portion, and the edge portion is located on opposite sides of the main body portion along the width direction of the pole piece. The maximum thickness of the edge portion is less than the minimum thickness of the main body portion, and the surface of the side of the edge portion facing away from the current collector is constructed as a planar structure. The pole piece also includes an insulating layer, and along the thickness direction of the current collector, the insulating layer is provided on the side of the edge portion facing away from the current collector.

[0006] In the technical solution of the present application, since the surface of the side of the edge portion facing away from the current collector is constructed as a planar structure, the edge portion is relatively flat and the thickness uniformity of the edge portion is high. In this way, the relatively flat edge portion provides a stable focal length for subsequent laser processing or other processing methods (laser processing or other processing methods will be used to remove the edge portion later), which is beneficial to improving the quality and consistency of the subsequent removal process; in addition, combined with the fact that the thickness of the edge portion is less than the thickness of the main portion, it can be understood that it is convenient to perform subsequent gluing or insulation processing on the relatively flat edge portion, so that the relatively flat edge portion provides a dimensionally stable position for subsequent gluing or insulation processing, which is beneficial to improving the quality and consistency of the subsequent gluing process; therefore, using the relatively flat edge portion can effectively improve the quality and consistency level of the electrode. In addition, the insulating layer can be used to electrically isolate the edges of adjacent electrode pieces, thereby reducing the risk of positive and negative electrode short circuits in the battery cell, thereby improving the insulation effect and quality of the battery cell.

[0007] In one embodiment, the compacted density of the main body is m1, and the compacted density of the edge portion is m2, wherein m1 and m2 have the same unit and satisfy the following condition: 0.9≤m2 / m1≤1.1.

[0008] The compaction density of the main part and the compaction density of the edge part tend to be consistent, reducing the situation where the compaction density at the edge of the pole piece is too low. It can be understood that the compaction density of the edge part of the present application is higher, which is conducive to increasing the supporting force of the edge part, thereby reducing the edge shrinkage and deformation of the pole piece of the battery cell during the isostatic pressing process, thereby reducing the risk of positive and negative pole short circuit due to edge shrinkage and deformation of the pole piece of the battery cell.

[0009] In one embodiment, m2≥3.0g / cm 3 .

[0010] Compared with the compaction density at the edge of the electrode in the related art, the compaction density of the edge part of the present application is higher, which is conducive to increasing the supporting force of the edge part, thereby reducing the edge shrinkage and deformation of the electrode of the battery cell during the isostatic pressing process, thereby reducing the risk of positive and negative electrode short circuit due to edge shrinkage and deformation of the electrode of the battery cell.

[0011] In one embodiment, the bonding force of the edge portion is 5 N / m-35 N / m.

[0012] Controlling the adhesive force of the edge portion within an appropriate range is beneficial to improving the bonding strength between the edge portion and the current collector, and reducing the probability of "the active material layer detaching from the current collector or the current collector leaking foil".

[0013] In one embodiment, the flatness of the edge portion is less than or equal to a preset value, which is 5 μm-25 μm.

[0014] The relatively flat edge portion provides a stable focal length for subsequent laser processing or other processing methods, which is beneficial to improving the quality and consistency of the subsequent cleaning process; in addition, it is also convenient for subsequent gluing or insulation treatment on the relatively flat edge portion, so that the relatively flat edge portion provides a dimensionally stable position for subsequent gluing or insulation treatment, which is beneficial to improving the quality and consistency of the subsequent gluing process; therefore, using the relatively flat edge portion can effectively improve the quality and consistency level of the electrode.

[0015] In one embodiment, the edge portion includes two sub-edge portions connected to opposite sides of the main portion along the width direction of the pole piece. The size of the sub-edge portion along the width direction of the pole piece is 0.5 mm-20 mm.

[0016] Setting the size of the sub-edge part along the width direction of the pole piece within a suitable range, for example, setting the size of the sub-edge part along the width direction of the pole piece to 0.5mm-20mm, is conducive to meeting the width requirements of the subsequent gluing process while also improving the supporting force of the edge part.

[0017] In one embodiment, the edge portion has a thickness of 1 μm-100 μm.

[0018] Setting the thickness of the edge portion within a suitable range, such as setting the thickness of the edge portion to 1 μm-100 μm, is conducive to ensuring that the compaction density of the edge portion meets the requirements and can also improve the supporting force of the edge portion.

[0019] In one embodiment, the insulating layer is elastic.

[0020] Since the insulating layer is elastic, the toughness of the pole piece can be improved, which is beneficial to reducing the risk of cracking of the pole piece of the battery cell during the isostatic pressing process.

[0021] In one embodiment, a surface of the insulating layer facing away from the current collector is flush with a surface of the main body facing away from the current collector.

[0022] In this way, a relatively flat electrode piece can be formed, thereby improving the force uniformity of the electrode piece of the battery cell during the isostatic pressing process, and further facilitating the improvement of the density of the battery cell.

[0023] According to a second aspect of the present application, a method for manufacturing a battery cell is provided, comprising: providing a current collector; wherein the current collector has a first surface and a second surface disposed opposite to each other along a thickness direction of the current collector; forming an active material layer on at least one of the first surface and the second surface; wherein the active material layer includes a main portion and an edge portion, the edge portion being located on opposite sides of the main portion along a width direction of the current collector. The maximum thickness of the edge portion is less than the minimum thickness of the main portion, and a surface of the edge portion facing away from the current collector is configured as a planar structure.

[0024] By utilizing the relatively flat edge portion, the quality rate and consistency level of the electrode can be effectively improved.

[0025] Forming an active material layer on at least one of the first surface and the second surface specifically includes: forming an initial active material layer on at least one of the first surface and the second surface; wherein the initial active material layer includes an initial edge portion corresponding to the edge portion; and cold pressing at least the initial edge portion of the initial active material layer.

[0026] The present application performs cold pressing on the initial edge portion of the initial active material layer by local cold pressing, thereby reducing the situation where the initial edge portion cannot be pressed, forming a relatively flat edge portion, and increasing the compaction density of the edge portion, thereby facilitating the improvement of the quality and consistency of the subsequent cleaning process, and also improving the quality and consistency of the subsequent gluing process, thereby facilitating the improvement of the quality and consistency level of the electrode.

[0027] In one embodiment, the initial active material layer further includes an initial main body portion corresponding to the main body portion; and cold pressing is performed on at least the initial edge portion of the initial active material layer, specifically including: cold pressing the initial main body portion and cold pressing the initial edge portion.

[0028] In this way, the compaction density and adhesion of the main part and the edge part can be improved, which is beneficial to improving the quality and consistency of the subsequent cleaning process, the quality and consistency of the subsequent gluing process, and the probability of the active material layer being separated from the current collector can be reduced, which is beneficial to improving the quality and consistency level of the electrode.

[0029] In one embodiment, the pressure applied to the initial edge portion is P, where 4905N≤P≤981000N.

[0030] The pressure applied to the initial edge portion satisfies the condition of "4905N≤P≤981000N", which is conducive to ensuring that the compaction density of the edge portion meets the requirements.

[0031] In one embodiment, the cold pressing time of the initial edge portion is 0.5s-10s.

[0032] The cold pressing time for the initial edge portion is set within an appropriate range, such as 0.5s-10s, so that the compaction density of the edge portion meets the requirements while also improving the production efficiency of the battery cell.

[0033] In one embodiment, cold pressing is performed on at least an initial edge portion of the initial active material layer, specifically comprising: clamping a clamp at at least the initial edge portion of the initial active material layer to cold press at least the initial edge portion with the help of the clamp.

[0034] At least the initial edge portion is cold pressed by using a clamp, and the clamp and the initial edge portion are in surface-to-surface contact, which can better improve the compaction density and bonding strength of the edge portion.

[0035] In one embodiment, the initial active material layer also includes an initial main body portion corresponding to the main body portion; the clamp includes a first clamping portion for clamping the initial main body portion, and a second clamping portion for clamping the initial edge portion; along the thickness direction of the initial active material layer, the second clamping portion is close to a side of the initial active material layer and protrudes beyond a side of the first clamping portion close to the initial active material layer.

[0036] The first clamping part of the clamp can be used to cold press the initial main part, and the second clamping part of the clamp can be used to cold press the initial edge part, thereby forming a relatively flat main part and edge part, and the maximum thickness of the edge part can be made smaller than the minimum thickness of the main part, thereby forming a convex pole piece intermediate, which is also beneficial to improving the quality rate of the pole piece.

[0037] In one embodiment, the flatness of the clamp surface near the initial active material layer is less than 10 μm. This improves the clamp installation accuracy, thereby facilitating the formation of a relatively flat main body and edge portion, thereby improving the quality rate of the electrode.

[0038] And / or the roughness of the surface of the clamp near the initial active material layer is less than 10 μm. This can make the surface of the clamp near the initial active material layer smoother, thereby facilitating the formation of a relatively flat main portion and edge portion, thereby improving the quality rate of the electrode.

[0039] In one embodiment, at least the initial edge portion of the initial active material layer is cold pressed, specifically comprising: clamping the initial edge portion with at least one roller group, so as to cold press the initial edge portion with the aid of at least one roller group; wherein the roller group comprises two rollers, and along the thickness direction of the initial edge portion, the two rollers are clamped on opposite sides of the initial edge portion.

[0040] In this way, the initial edge portion can be cold pressed using at least one roller set to increase the compaction density and bonding strength of the edge portion.

[0041] In one embodiment, the circular runout of the roller in the radial direction of the roller is less than 2 μm.

[0042] In this way, the installation error of the roller group can be reduced, which is conducive to forming a relatively flat main part and edge part, and is conducive to improving the quality rate of the pole piece.

[0043] In one embodiment, after cold pressing at least an initial edge portion of the initial active material layer, forming the active material layer on at least one of the first surface and the second surface further comprises: performing a thickness reduction process on the initial edge portion to form the active material layer.

[0044] In this way, the surface cleanliness of the edge portion corresponding to the initial edge portion can be improved, thereby improving the quality rate of the electrode piece.

[0045] According to a third aspect of the present application, a battery device is provided, comprising a battery cell according to any one of the above embodiments or a battery cell manufactured by the method for manufacturing a battery cell according to any one of the above embodiments.

[0046] According to a fourth aspect of the present application, an electrical device is provided, comprising the above-mentioned battery device.

[0047] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0049] Figure 1 A structural schematic diagram of a vehicle according to an embodiment of the present application is shown.

[0050] Figure 2 A schematic diagram of an explosion of a battery cell according to an embodiment of the present application is shown.

[0051] Figure 3 A schematic structural diagram of a pole piece according to an embodiment of the present application is shown.

[0052] Figure 4 A schematic structural diagram of a pole piece according to another embodiment of the present application is shown.

[0053] Figure 5 A schematic diagram of the first process of a method for manufacturing a pole piece according to an embodiment of the present application is shown.

[0054] Figure 6 A schematic diagram of the second process of the method for manufacturing a pole piece according to an embodiment of the present application is shown.

[0055] Figure 7 A schematic diagram of the second process of a method for manufacturing a pole piece according to another embodiment of the present application is shown.

[0056] Figure 8 A schematic diagram of the third process of the method for manufacturing a pole piece according to an embodiment of the present application is shown.

[0057] Figure numerals: 1. vehicle; 10. battery device; 100. electrode assembly; 110. pole piece; 111. current collector; 1111. first surface; 1112. second surface; 112. active material layer; 1121. main body; 1122. edge portion; 11221. sub-edge portion; 112a. initial active material layer; 112b. initial edge portion; 112c. initial main body; 113. insulating layer; 200. shell; 210. bottom shell; 220. top cover; 300. pole; 20. motor; 30. controller; 40. clamp; 410. first clamping portion; 420. second clamping portion; 421. sub-clamping portion; 50. roller group; 510. roller. DETAILED DESCRIPTION

[0058] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0059] In the description of this application, it should be understood that if the 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. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing this application and simplifying 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 a limitation on this application.

[0060] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of this application, if the term "plurality" appears, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0061] In this application, unless otherwise specified or limited, the terms "mounted," "connected," "connected," "fixed," etc., should be interpreted broadly. For example, these terms may refer to fixed connections, removable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediary; and internal communication between two components or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0062] In this application, unless otherwise expressly specified or limited, if a first feature is described as being "above" or "below" a second feature, or similar descriptions, this may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is described as being "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is described as being "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0063] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only embodiment.

[0064] In the related art, the edge of the active material layer of the electrode will present an arc-shaped distribution due to the leveling of the slurry, that is, the thickness of the edge of the active material layer tends to gradually decrease, and the farther away from the center of the active material layer, the smaller the thickness of the edge of the active material layer.

[0065] Normally, laser cleaning operations are required at the edge of the active material layer in order to carry out the subsequent glue coating process at the edge of the electrode. However, in the subsequent laser cleaning process, this arc-shaped distribution of the edge is prone to cause local over-etching of the electrode (the thinner thickness at the edge of the active material layer), causing the active material layer to easily separate from the current collector or causing the current collector to leak foil, thereby affecting the quality rate of the electrode.

[0066] In order to solve the problem of low quality rate of electrode pieces, the present application designs a battery cell, a battery device, an electrical equipment and a manufacturing method of a battery cell, which can make the edge portion of the active material layer of the electrode piece facing away from the surface of the current collector be constructed into a planar structure, so that the relatively flat edge portion provides a stable focal length for subsequent laser processing or other processing methods, and also facilitates subsequent gluing or insulation treatment on the relatively flat edge portion, thereby improving the quality rate of the electrode piece.

[0067] The battery cells and / or battery devices disclosed in the embodiments of the present application can be used, but are not limited to, in electrical equipment such as vehicles, ships or aircraft. Electrical equipment can be, but are not limited to, mobile phones, tablets, laptops, electric toys, electric tools, battery cars, electric cars, ships and spacecraft, etc. Among them, electric toys can include fixed or mobile electric toys, for example, game consoles, electric car toys, electric ship toys and electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles and spacecraft, etc. The power supply system of the electrical equipment can be composed of the battery cells and / or battery devices disclosed in this application, so that it is convenient to provide electric drive for the electrical equipment and the service life of the electrical equipment can be increased.

[0068] Figure 1 A structural schematic diagram of a vehicle 1 according to an embodiment of the present application is shown. The vehicle 1 may be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery device 10 is provided inside the vehicle 1. For example, a battery device 10 may be provided at the bottom, front or rear of the vehicle 1. The battery device 10 may be used to power the vehicle 1. For example, the battery device 10 may be used as an operating power source for the vehicle 1, for the circuit system of the vehicle 1, such as for the working power requirements during the start-up, navigation and operation of the vehicle 1. In another embodiment of the present application, the battery device 10 may not only be used as an operating power source for the vehicle 1, but also as a driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving force for the vehicle 1.

[0069] A motor 20 and a controller 30 may also be provided inside the vehicle 1 . The controller 30 is used to control the battery device 10 to supply power to the motor 20 , for example, to meet the power requirements for starting, navigating, and driving the vehicle 1 .

[0070] Figure 2 A schematic diagram of an explosion of a battery cell according to an embodiment of the present application is shown.

[0071] See also Figure 2A battery cell according to an embodiment of the present application includes an electrode assembly 100 and a shell 200. The shell 200 includes a bottom shell 210 and a top cover 220 disposed on the bottom shell 210. The bottom shell 210 and the top cover 220 enclose a receiving space for accommodating the electrode assembly 100. The electrode assembly 100 can be accommodated in the receiving space, and the shell 200 can be used to well protect the electrode assembly 100.

[0072] The battery cell further includes a pole 300, and the electrode assembly 100 includes a pole piece 110. The tab of the pole piece 110 is electrically connected to the pole 300. The electrode assembly 100 may include a first pole piece and a second pole piece, and at least one of the first pole piece and the second pole piece is the pole piece 110. Specifically, one of the first pole piece and the second pole piece is a positive pole piece, and the other of the first pole piece and the second pole piece is a negative pole piece. The battery cell further includes two poles 300, one of the two poles 300 is electrically connected to the tab of the positive pole piece, and the other of the two poles 300 is electrically connected to the tab of the negative pole piece.

[0073] Figure 3 and Figure 4 Schematic diagrams of the structures of the pole pieces 110 according to different embodiments of the present application are shown respectively.

[0074] Please refer to Figure 3 and Figure 4 The pole piece 110 of one embodiment of the present application includes a current collector 111 and an active material layer 112. Along the thickness direction of the current collector 111, the current collector 111 has a first surface 1111 and a second surface 1112 disposed opposite to each other. The active material layer 112 is disposed on at least one of the first surface 1111 and the second surface 1112.

[0075] The current collector 111 is a component on the electrode 110 for supporting the active material layer 112 and collecting the current generated by the active material layer 112. The current collector 111 can be aluminum foil or copper foil.

[0076] The active material layer 112 refers to a material layer disposed on at least one of the first surface 1111 and the second surface 1112 of the current collector 111 . The active material layer 112 may include an active material, a conductive agent, a binder, and the like.

[0077] “An active material layer 112 is provided on at least one of the first surface 1111 and the second surface 1112 ” may mean: an active material layer 112 is provided on the first surface 1111 (e.g. Figure 3 As shown); it can also be: an active material layer 112 is provided on the second surface 1112; it can also be that the first surface 1111 and the second surface 1112 are respectively provided with an active material layer 112 (as shown Figure 4 shown).

[0078] Among them, the active material layer 112 includes a main part 1121 and an edge part 1122, the edge part 1122 is located on opposite sides of the main part 1121 along the width direction of the pole piece 110, the maximum thickness of the edge part 1122 is less than the minimum thickness of the main part 1121, and the surface of the side of the edge part 1122 away from the current collector 111 is constructed as a planar structure.

[0079] The main body portion 1121 refers to a portion of the active material layer 112 located inside the edge portion 1122 and occupying a larger proportion of the active material layer 112 .

[0080] The edge portion 1122 refers to a portion of the active material layer 112 that is located outside the main body portion 1121 and occupies a smaller proportion of the active material layer 112 .

[0081] The width direction W of the pole piece 110, the length direction L of the pole piece 110, and the thickness direction Z of the pole piece 110 are perpendicular to each other. Among them, the thickness direction Z of the pole piece 110 is parallel to the thickness direction of the current collector 111, and the length direction L of the pole piece 110 refers to the conveying direction of the strip corresponding to the pole piece 110. It can be understood that during the production process, the pole piece 110 is continuously conveyed and processed along the length direction L of the pole piece 110, and the width direction W represents the lateral dimension direction of the pole piece 110. The length dimension of the pole piece 110 and the width dimension of the pole piece 110 can be equal or different, and the size between the two can be determined according to the slitting process, and no specific limitation is made here.

[0082] The strip corresponding to the pole piece 110 will be cut at a certain interval along the length direction L of the pole piece 110. Therefore, the edge portion 1122 is connected to the opposite sides of the main portion 1121 along the width direction of the pole piece 110, which can meet the application requirements of the scenario of "the strip corresponding to the pole piece 110 is cut at a certain interval along the length direction L of the pole piece 110".

[0083] Since the surface of the side of the edge portion 1122 facing away from the collector 111 is constructed as a planar structure, the edge portion 1122 is relatively flat, and the thickness uniformity of the edge portion 1122 is high. In this way, the position where the edge portion 1122 needs to be cleared is constructed as a planar structure, so that the relatively flat edge portion 1122 provides a stable focal length for subsequent laser processing or other processing methods (laser processing or other processing methods will be used to clear the edge portion 1122 later), which is beneficial to improving the quality and consistency of the subsequent cleaning process; in addition, combined with the fact that the thickness of the edge portion 1122 is less than the thickness of the main portion 1121, it can be understood that it is convenient to carry out subsequent gluing or insulation treatment on the relatively flat edge portion 1122, so that the relatively flat edge portion 1122 provides a dimensionally stable position for subsequent gluing or insulation treatment, which is beneficial to improving the quality and consistency of the subsequent gluing process; therefore, using the relatively flat edge portion 1122, the quality and consistency level of the electrode 110 can be effectively improved.

[0084] In some embodiments, the flatness of the edge portion 1122 is less than or equal to a predetermined value, and the predetermined value is 5 μm-25 μm.

[0085] Illustratively, the preset value is 5 μm, 10 μm, 15 μm, 20 μm or 25 μm.

[0086] The relatively flat edge portion 1122 provides a stable focal length for subsequent laser processing or other processing methods, which is beneficial to improving the quality and consistency of the subsequent cleaning process; it is also convenient for subsequent gluing or insulation treatment on the relatively flat edge portion 1122, so that the relatively flat edge portion 1122 provides a dimensionally stable position for subsequent gluing or insulation treatment, which is beneficial to improving the quality and consistency of the subsequent gluing process; therefore, using the relatively flat edge portion 1122 can effectively improve the quality and consistency level of the pole piece 110.

[0087] In some embodiments, the compaction density of the main portion 1121 is m1, and the compaction density of the edge portion 1122 is m2, wherein m1 and m2 have the same unit and m1 and m2 satisfy the following condition: 0.9≤m2 / m1≤1.1.

[0088] Illustratively, m2 / m1 may be 0.9, 1.0, or 1.1.

[0089] Since m1 and m2 satisfy the following conditions: 0.9≤m2 / m1≤1.1, the compaction density of the main part 1121 and the compaction density of the edge part 1122 tend to be consistent, reducing the situation where the compaction density at the edge of the pole piece 110 is too low. It can be understood that the compaction density of the edge part 1122 of the present application is relatively high, which is conducive to increasing the supporting force of the edge part 1122, thereby reducing the edge shrinkage and deformation of the pole piece 110 of the battery cell during the isostatic pressing process, thereby reducing the risk of positive and negative pole overlap short circuit due to edge shrinkage and deformation of the pole piece 110 of the battery cell.

[0090] In some embodiments, m2≥3.0 g / cm 3 .

[0091] m2 can be 3.0g / cm 3 , 3.1g / cm 3 、3.2g / cm 3 , 3.3g / cm 3 、3.4g / cm 3 or 3.5g / cm 3 wait.

[0092] In this way, compared with the compaction density at the edge of the electrode in the related art, the compaction density of the edge part 1122 of the present application is higher, which is conducive to increasing the supporting force of the edge part 1122, thereby reducing the edge shrinkage and deformation of the electrode 110 of the battery cell during the isostatic pressing process, thereby reducing the risk of positive and negative electrode short circuit due to edge shrinkage and deformation of the electrode 110 of the battery cell.

[0093] In some embodiments, the adhesive force of the edge portion 1122 is 5 N / m-35 N / m.

[0094] Illustratively, the adhesive force of the edge portion 1122 is 5 N / m, 10 N / m, 15 N / m, 20 N / m, 25 N / m, 30 N / m, or 35 N / m.

[0095] Controlling the adhesive force of the edge portion 1122 within a suitable range is beneficial to improving the bonding strength between the edge portion 1122 and the current collector 111 and reducing the probability of the active material layer 112 separating from the current collector 111 or the current collector 111 leaking foil.

[0096] In some embodiments, the edge portion 1122 is connected to two opposite sides of the main portion 1121 along the width direction of the pole piece 110 , wherein the width direction of the pole piece 110 is perpendicular to the thickness direction of the current collector 111 .

[0097] In some embodiments, the edge portion 1122 includes two sub-edge portions 11221, which are connected to opposite sides of the main portion 1121 along the width direction of the pole piece 110. The size of the sub-edge portion 11221 along the width direction of the pole piece 110 is 0.5mm-20mm.

[0098] For example, the dimension of the sub-edge portion 11221 along the width direction of the pole piece 110 is 0.5 mm, 1 mm, 2 mm, 4 mm, 6 mm, 8 mm, 10 mm, 12 mm, 14 mm, 16 mm, 18 mm or 20 mm.

[0099] The size of the sub-edge portion 11221 along the width direction of the pole piece 110 is set within a suitable range. For example, the size of the sub-edge portion 11221 along the width direction of the pole piece 110 is set to 0.5mm-20mm. This is conducive to meeting the width requirements of the subsequent gluing process while also improving the supporting force of the edge portion 1122.

[0100] In some embodiments, the edge portion 1122 has a thickness of 1 μm-100 μm.

[0101] Illustratively, the thickness of edge portion 1122 is 1 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, or 100 μm.

[0102] Setting the thickness of the edge portion 1122 within a suitable range, for example, setting the thickness of the edge portion 1122 to 1 μm-100 μm, is conducive to ensuring that the compaction density of the edge portion 1122 meets the requirements and can also improve the supporting force of the edge portion 1122 .

[0103] In some embodiments, the pole piece 110 further includes an insulating layer 113 . Along the thickness direction of the current collector 111 , the insulating layer 113 is disposed on a side of the edge portion 1122 facing away from the current collector 111 .

[0104] In this way, the insulating layer 113 can be used to electrically isolate the edges of adjacent electrode pieces 110 , thereby reducing the risk of positive and negative electrode short circuits in the battery cells, thereby improving the insulation effect and quality of the battery cells.

[0105] In some embodiments, the insulating layer 113 is elastic.

[0106] For example, the insulating layer 113 may be insulating glue.

[0107] Since the insulating layer 113 is elastic, the toughness of the pole piece 110 can be improved, which is beneficial to reducing the risk of cracking of the pole piece 110 of the battery cell during the isostatic pressing process.

[0108] In some embodiments, a surface of the insulating layer 113 facing away from the current collector 111 is flush with a surface of the main body 1121 facing away from the current collector 111 .

[0109] In this way, a relatively flat electrode piece 110 can be formed, thereby improving the force uniformity of the electrode piece 110 of the battery cell during the isostatic pressing process, thereby facilitating the improvement of the density of the battery cell.

[0110] In some embodiments, the battery cells may be solid-state battery cells.

[0111] An embodiment of the present application provides a method for manufacturing a battery cell, comprising:

[0112] S10 , providing a current collector 111 ; wherein, along a thickness direction of the current collector 111 , the current collector 111 has a first surface 1111 and a second surface 1112 that are disposed opposite to each other.

[0113] S20, forming an active material layer 112 (eg, Figure 5 shown).

[0114] Active material layer 112 includes a main portion 1121 and an edge portion 1122. Edge portions 1122 are located on opposite sides of main portion 1121 along the width direction of current collector 111. The maximum thickness of edge portion 1122 is less than the minimum thickness of main portion 1121, and the surface of edge portion 1122 facing away from current collector 111 is flat. The width direction of current collector 111 is parallel to the width direction of electrode 110.

[0115] By utilizing the relatively flat edge portion 1122 , the quality and consistency of the pole piece 110 can be effectively improved.

[0116] In some embodiments, step S20 of forming the active material layer 112 on at least one of the first surface 1111 and the second surface 1112 specifically includes:

[0117] S21, forming an initial active material layer 112a on at least one of the first surface 1111 and the second surface 1112; wherein the initial active material layer 112a includes an initial edge portion 112b corresponding to the edge portion 1122;

[0118] S22 , cold pressing at least the initial edge portion 112 b of the initial active material layer 112 a .

[0119] Compared with the overall cold pressing of the initial active material layer 112a (during the overall cold pressing of the initial active material layer 112a, there is a situation where the initial edge portion 112b cannot be pressed), the present application cold presses the initial edge portion 112b of the initial active material layer 112a by local cold pressing, thereby reducing the situation where the initial edge portion 112b cannot be pressed, forming a relatively flat edge portion 1122, and also improving the compaction density of the edge portion 1122, which is beneficial to improving the quality and consistency of the subsequent cleaning process, and also improving the quality and consistency of the subsequent glue coating process, which is beneficial to improving the quality and consistency level of the electrode 110.

[0120] In addition, compared to the hot pressing process (because the hot pressing process is prone to severe adhesion due to the stickiness of the pole piece during the hot pressing process, the hot pressing process is more suitable for the electrode assembly level), the present application adopts a cold pressing process to reduce the severe adhesion of the pole piece 110 to the clamp 40 or the roller 510, which is conducive to the better application of the battery cell manufacturing method of the present application to the pole piece level, and compared to the application to the electrode assembly 100 level (if under the same pressure, the pressure acting on the electrode assembly 100 is difficult to act on the initial edge portion 112b; in the case of application to the electrode assembly 100 level , if the same compaction density is achieved, a greater pressure may be required to act on the initial active material layer 112a, resulting in the initial active material layer 112a being crushed). The battery cell manufacturing method of the present application can be applied to the electrode layer. If the same compaction density is achieved, a smaller pressure can be applied to the initial active material layer 112a to reduce the possibility of crushing the initial active material layer 112a. Local cold pressing is performed on the initial edge portion 112b, which is beneficial to better improve the compaction density and adhesion strength of the edge portion 1122, and is also beneficial to improving the quality rate of the electrode 110.

[0121] In addition, by cold pressing the initial edge portion 112 b , the active material and the binder of the initial edge portion 112 b can be mixed evenly, thereby facilitating improvement of the adhesive force of the edge portion 1122 .

[0122] In some embodiments, the initial active material layer 112a further includes an initial main body portion 112c corresponding to the main body portion 1121. The step S22 of cold-pressing at least the initial edge portion 112b of the initial active material layer 112a specifically includes:

[0123] S221 . Cold-press the initial main body portion 112 c and the initial edge portion 112 b .

[0124] The initial main portion 112c may be cold pressed first, and then the initial edge portion 112b may be cold pressed; the initial edge portion 112b may be cold pressed first, and then the initial main portion 112c may be cold pressed; the initial main portion 112c may also be cold pressed while the initial edge portion 112b is also cold pressed; no specific limitation is given here.

[0125] It can be understood that since the initial main portion 112c accounts for a large proportion, the initial main portion 112c almost accounts for more than 90% of the initial active material layer 112a. Therefore, cold pressing the initial main portion 112c is equivalent to cold pressing the initial active material layer 112a as a whole.

[0126] The whole part 1121 and the part 1122 can be cold pressed first, and then the part 1122 can be cold pressed locally, or the part 1121 and the whole part can be cold pressed first. In this way, the compaction density and adhesion of the main part 1121 and the edge part 1122 can be improved, which is beneficial to improving the quality and consistency of the subsequent cleaning process, and the quality and consistency of the subsequent gluing process can also be improved. It can also reduce the probability of the active material layer 112 separating from the current collector 111, which is beneficial to improving the quality and consistency level of the electrode 110.

[0127] In some embodiments, the pressure applied to the initial edge portion 112b is P, where 4905N≤P≤981000N.

[0128] For example, P may be 4905N, 9810N, 98100N, or 981000N.

[0129] It can be connected to the following clamp 40 or roller group 50 through a hydraulic cylinder to apply corresponding pressure to the initial edge portion 112b. The pressure of the pressure oil to be supplied to the hydraulic cylinder can be set according to the pressure applied to the initial edge portion 112b, so that the pressure applied to the initial edge portion 112b meets the condition of "4905N≤P≤981000N", which is conducive to making the compaction density of the edge portion 1122 meet the requirements.

[0130] In some embodiments, the cold pressing time for the initial edge portion 112b is 0.5s-10s.

[0131] Illustratively, the cold pressing time for cold pressing the initial edge portion 112b is 0.5s, 1s, 2s, 3s, 4s, 5s, 6s, 7s, 8s, 9s, or 10s.

[0132] The cold pressing time for the initial edge portion 112b is set within an appropriate range, such as 0.5s-10s, so that the compaction density of the edge portion 1122 meets the requirements while also improving the production efficiency of the battery cell.

[0133] In some embodiments, the step S22 of cold pressing at least the initial edge portion 112b of the initial active material layer 112a specifically includes:

[0134] S222, clamping the clamp 40 at least on the initial edge portion 112b of the initial active material layer 112a, so as to cold-press at least the initial edge portion 112b by means of the clamp 40 (e.g., Figure 6 shown).

[0135] The clamp 40 can be clamped at least at the initial edge portion 112b of the initial active material layer 112a so as to cold-press at least the initial edge portion 112b with the aid of the clamp 40; the clamp 40 can also be clamped at the initial edge portion 112b and the initial main body portion 112c respectively so as to cold-press the initial active material layer 112a with the aid of the clamp 40; no specific limitation is imposed here.

[0136] It should be noted that, in this embodiment, the initial edge portion 112 b may be locally cold-pressed using the clamp 40 , and then the initial active material layer 112 a may be entirely cold-pressed using a pressing roller.

[0137] At least the initial edge portion 112 b is cold-pressed by using the clamp 40 , and the clamp 40 and the initial edge portion 112 b are in surface-to-surface contact, which can better improve the compaction density and adhesion of the edge portion 112 .

[0138] In some embodiments, the clamp 40 includes a first clamping portion 410 for clamping the initial main body portion 112c, and a second clamping portion 420 for clamping the initial edge portion 112b. Along the thickness direction of the initial active material layer 112a, the second clamping portion 420 is close to the side of the initial active material layer 112a and protrudes from the side of the first clamping portion 410 close to the initial active material layer 112a.

[0139] The initial main portion 112 c refers to a portion of the initial active material layer 112 a having a smaller thickness variation and a smaller flatness, and the initial edge portion 112 b refers to a portion of the initial active material layer 112 a having a gradually varying thickness.

[0140] The first clamping portion 410 is a portion of the clamp 40 for clamping the initial main body portion 112c. The second clamping portion 420 is a portion of the clamp 40 for clamping the initial edge portion 112b.

[0141] The initial edge portion 112b includes two sub-initial edge portions (not shown in the figure) corresponding one to one to the two sub-edge portions 11221, and the second clamping portion 420 includes four sub-clamping portions 421, two of which are used to clamp one of the sub-initial edge portions, and the other two sub-clamping portions 421 are used to clamp the other sub-initial edge portion.

[0142] Since the second clamping portion 420 is close to the side of the initial active material layer 112a and protrudes from the side of the first clamping portion 410 close to the initial active material layer 112a, in the process of using the clamp 40 to clamp the initial active material layer 112a with a certain pressure, the first clamping portion 410 of the clamp 40 can be used to cold press the initial main body portion 112c, and the second clamping portion 420 of the clamp 40 can be used to cold press the initial edge portion 112b, thereby forming a relatively flat main body portion 1121 and edge portion 1122, and the maximum thickness of the edge portion 1122 can be made smaller than the minimum thickness of the main body portion 1121, thereby forming a convex pole piece intermediate, which is also beneficial to improving the quality rate of the pole piece 110.

[0143] In some embodiments, the flatness of the surface of the jig 40 on one side close to the initial active material layer 112 a is less than 10 μm.

[0144] For example, the flatness of the surface of the jig 40 on one side close to the initial active material layer 112 a is 1 μm or 5 μm.

[0145] In this way, the installation accuracy of the fixture 40 can be improved, which is conducive to forming a relatively flat main portion 1121 and edge portion 1122, and is conducive to improving the quality rate of the pole piece 110.

[0146] In some embodiments, the roughness of the surface of the jig 40 close to the initial active material layer 112 a is less than 10 μm.

[0147] For example, the roughness of the surface of the jig 40 on the side close to the initial active material layer 112 a is 1 μm or 5 μm.

[0148] In this way, the surface of the clamp 40 close to the initial active material layer 112 a can be made smoother, thereby facilitating the formation of a relatively flat main portion 1121 and edge portion 1122 , thereby facilitating the improvement of the quality of the electrode piece 110 .

[0149] In some embodiments, the step S22 of cold pressing at least the initial edge portion 112b of the initial active material layer 112a specifically includes:

[0150] S223, clamping the initial edge portion 112b with at least one roller group 50, so as to cold press the initial edge portion 112b with the help of at least one roller group 50 (such as Figure 7 shown).

[0151] The roller assembly 50 includes two rollers 510 , and along the thickness direction of the initial edge portion 112 b , the two rollers 510 are clamped at opposite sides of the initial edge portion 112 b .

[0152] It may be that, along the thickness direction of the initial edge portion 112 b , one roller set 50 is clamped at two opposite sides of one sub-edge portion 11221 , and another roller set 50 is clamped at two opposite sides of the other sub-edge portion 11221 .

[0153] In this embodiment, before or after step S223 , two pressing rollers (not shown in the figure) may be used to cold-press the initial main body portion 112 c .

[0154] In this way, the initial edge portion 112 b may be cold pressed using at least one roller set 50 to increase the compaction density and adhesive strength of the edge portion 112 .

[0155] It should be noted that, according to the design requirements of the compaction density and adhesion strength of the edge portion 1122, the clamp 40 or at least one roller group 50 can be selected to cold press at least the initial edge portion 112b. For example, if there is a design requirement for high pressure density, the clamp 40 can be selected to cold press at least the initial edge portion 112b; if there is a design requirement for low pressure density, at least one roller group 50 can be selected to cold press the initial edge portion 112b.

[0156] In some embodiments, the circular runout of the roller 510 in the radial direction of the roller 510 is less than 2 μm.

[0157] In this way, the installation error of the roller assembly 50 can be reduced, which is conducive to forming a relatively flat main portion 1121 and edge portion 1122 , and is conducive to improving the quality rate of the pole piece 110 .

[0158] In some embodiments, after step S22 of cold pressing at least the initial edge portion 112b of the initial active material layer 112a, step S20 of forming the active material layer 112 on at least one of the first surface 1111 and the second surface 1112 further includes:

[0159] S23, the initial edge portion 112b is subjected to a thickness reduction process to form an active material layer 112 (which can be combined with Figure 6 and Figure 8 to understand).

[0160] In this way, the surface cleanliness of the edge portion 1122 corresponding to the initial edge portion 112 b can be improved, thereby improving the quality rate of the electrode piece 110 .

[0161] In some embodiments, the method for manufacturing a battery cell further includes:

[0162] A plurality of first pole pieces and a plurality of second pole pieces are alternately stacked and pressed together, wherein at least one of the first pole pieces and the second pole pieces is the pole piece 110 .

[0163] The plurality of first pole pieces and the plurality of second pole pieces after the pressing process are subjected to a glue injection process to obtain an initial electrode assembly.

[0164] The initial electrode assembly is subjected to isostatic pressing to obtain the electrode assembly 100 .

[0165] The electrode assembly 100 is assembled into the housing 200 to obtain a battery cell.

[0166] In some embodiments, the flatness of the edge portion 1122 is less than or equal to a preset value, which is 5 μm-25 μm, and m1 and m2 satisfy the following condition: 0.9≤m2 / m1≤1.1.

[0167] Compared with the pole piece in the related art (the flatness at the edge of the pole piece in the related art is 30μm-100μm, and the compaction density at the edge of the pole piece in the related art is 2.0g / cm 3 , the bonding force at the edge of the pole piece in the related art is 0.5N / m), the flatness of the edge portion 1122 of the present application is 5μm-25μm, which is conducive to significantly improving the subsequent laser cleaning and the excellent rate of applying the insulating glue. Specifically, the excellent rate of the subsequent laser cleaning and the coating of the insulating glue is improved by about 20%-30%; by measuring the weight and thickness of the edge portion 1122 of the pole piece 110, it is known that the compaction density of the edge portion 1122 of the pole piece 110 is increased to 3.5g / cm 3 ; Through the adhesion test, it is known that the adhesion of the edge portion 1122 of the pole piece 110 is increased to 35N / m. Therefore, by using the battery cell and the battery cell manufacturing method of the present application, the compaction density and adhesion of the edge portion 1122 can be improved, and the quality rate of the pole piece 110 can also be improved.

[0168] An embodiment of the present application provides a battery device 10, comprising a battery cell according to any of the above embodiments or a battery cell manufactured by the manufacturing method of the battery cell according to any of the above embodiments.

[0169] The battery device 10 may include one battery cell, or may include multiple battery cells, which are connected in series, in parallel, or in a hybrid manner, wherein the hybrid manner is a combination of series and parallel.

[0170] An embodiment of the present application provides an electrical device, including the battery device 10 described above.

[0171] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0172] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A method for manufacturing a battery cell, characterized in that: include: A current collector (111) is provided; wherein, along a thickness direction of the current collector (111), the current collector (111) has a first surface (1111) and a second surface (1112) disposed opposite to each other; forming an active material layer (112) on at least one of the first surface (1111) and the second surface (1112); The active material layer (112) comprises a main body portion (1121) and an edge portion (1122), and the edge portion (1122) is located on two opposite sides of the main body portion (1121) along the width direction of the current collector (111); The maximum thickness of the edge portion (1122) is less than the minimum thickness of the main body portion (1121), and the surface of the edge portion (1122) facing away from the current collector (111) is constructed as a planar structure; The forming of the active material layer (112) on at least one of the first surface (1111) and the second surface (1112) specifically comprises: forming an initial active material layer (112a) on at least one of the first surface (1111) and the second surface (1112); wherein the initial active material layer (112a) includes an initial edge portion (112b) corresponding to the edge portion (1122) and an initial main body portion (112c) corresponding to the main body portion (1121); cold pressing at least the initial edge portion (112b) of the initial active material layer (112a); The initial edge portion (112b) is distributed in an arc shape due to the leveling of the slurry; and the thickness of the initial edge portion (112b) gradually decreases from a side of the initial edge portion (112b) close to the center of the initial active material layer (112a) to a side of the initial edge portion (112b) away from the center of the initial active material layer (112a).

2. The method for manufacturing a battery cell according to claim 1, wherein: The step of cold pressing at least the initial edge portion (112b) of the initial active material layer (112a) specifically comprises: The initial body portion (112c) is cold pressed, and the initial edge portion (112b) is cold pressed.

3. The method for manufacturing a battery cell according to claim 1, wherein: The pressure applied to the initial edge portion (112b) is P; Among them, 4905N≤P≤981000N.

4. The method for manufacturing a battery cell according to claim 3, wherein: The cold pressing time for cold pressing the initial edge portion (112b) is 0.5s-10s.

5. The method for manufacturing a battery cell according to claim 1, wherein: The step of cold pressing at least the initial edge portion (112b) of the initial active material layer (112a) specifically comprises: A clamp (40) is clamped at least on the initial edge portion (112b) of the initial active material layer (112a) to cold-press at least the initial edge portion (112b) by means of the clamp (40).

6. The method for manufacturing a battery cell according to claim 5, wherein: The clamp (40) comprises a first clamping portion (410) for clamping the initial main body portion (112c), and a second clamping portion (420) for clamping the initial edge portion (112b); Along the thickness direction of the initial active material layer (112a), the second clamping portion (420) is close to a side of the initial active material layer (112a) and protrudes beyond a side of the first clamping portion (410) close to the initial active material layer (112a).

7. The method for manufacturing a battery cell according to claim 5, wherein: The flatness of a surface of one side of the clamp (40) close to the initial active material layer (112a) is less than 10 μm.

8. The method for manufacturing a battery cell according to claim 1, wherein: The step of cold pressing at least the initial edge portion (112b) of the initial active material layer (112a) specifically comprises: Using at least one roller group (50) to clamp the initial edge portion (112b), so as to cold-press the initial edge portion (112b) with the aid of the at least one roller group (50); The roller group (50) comprises two rollers (510), and along the thickness direction of the initial edge portion (112b), the two rollers (510) are clamped on opposite sides of the initial edge portion (112b).

9. The method for manufacturing a battery cell according to claim 8, wherein: In the radial direction of the roller (510), the circular runout of the roller (510) is less than 2 μm.

10. The method for manufacturing a battery cell according to claim 1, wherein: After cold pressing at least the initial edge portion (112b) of the initial active material layer (112a), forming the active material layer (112) on at least one of the first surface (1111) and the second surface (1112) further comprises: The initial edge portion (112b) is subjected to a thickness reduction process to form the active material layer (112).

11. A battery cell, characterized in that: The battery cell is prepared by the method for manufacturing a battery cell according to any one of claims 1 to 10; the battery cell comprises a pole piece (110), and the pole piece (110) comprises: A current collector (111), wherein along a thickness direction of the current collector (111), the current collector (111) has a first surface (1111) and a second surface (1112) disposed opposite to each other; and an active material layer (112), wherein the active material layer (112) is provided on at least one of the first surface (1111) and the second surface (1112); The active material layer (112) includes a main body portion (1121) and an edge portion (1122). The edge portion (1122) is located on two opposite sides of the main body portion (1121) along the width direction of the pole piece (110); The maximum thickness of the edge portion (1122) is less than the minimum thickness of the main body portion (1121), and the surface of the edge portion (1122) facing away from the current collector (111) is constructed as a planar structure; The pole piece (110) further includes an insulating layer (113); Along the thickness direction of the current collector (111), the insulating layer (113) is provided on a side of the edge portion (1122) facing away from the current collector (111).

12. The battery cell according to claim 11, characterized in that The compaction density of the main body portion (1121) is m1, and the compaction density of the edge portion (1122) is m2; Among them, m1 and m2 have the same unit, and m1 and m2 meet the following conditions: 0.9≤m2 / m1≤1.

1.

13. The battery cell according to claim 12, characterized in that: m2≥3.0g / cm 3 。 14. The battery cell according to claim 11, characterized in that The bonding force of the edge portion (1122) is 5N / m-35N / m.

15. The battery cell according to claim 11, characterized in that The flatness of the edge portion (1122) is less than or equal to a preset value; the preset value is 5μm-25μm.

16. The battery cell according to claim 15, characterized in that The edge portion (1122) includes two sub-edge portions (11221); The two sub-edge portions (11221) are connected to opposite sides of the main body portion (1121) along the width direction of the pole piece (110); The dimension of the sub-edge portion (11221) along the width direction of the pole piece (110) is 0.5 mm to 10 mm.

17. The battery cell according to any one of claims 11 to 16, characterized in that: The thickness of the edge portion (1122) is 1 μm-100 μm.

18. The battery cell according to any one of claims 11 to 16, characterized in that: The insulating layer (113) is elastic.

19. The battery cell according to any one of claims 11 to 16, characterized in that: A surface of the insulating layer (113) facing away from the current collector (111) is flush with a surface of the main body (1121) facing away from the current collector (111).

20. A battery device, characterized in that: The invention comprises a battery cell according to any one of claims 11 to 19 or a battery cell prepared by the method for preparing a battery cell according to any one of claims 1 to 10.

21. An electrical device, characterized in that: Comprising the battery device of claim 20.

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