Pole, cover assembly and battery cell

Abstract

The present invention provides a pole, a cover plate assembly and a battery cell, and relates to the field of battery technology. The pole is used for a battery cell, and the pole includes a pole body and a bottom plate, the pole body is connected to the bottom plate, and the bottom plate includes a first plate portion and a second plate portion, the first plate portion is connected to the second plate portion on one side of the thickness direction of the battery cell, the second plate portion is used to connect to the pole ear, and the size of the first plate portion in the length direction of the battery cell is larger than the size of the second plate portion in the length direction. In this way, only the first plate portion is flush with the lower end surface of the first plastic part, which can prevent the first plastic part from cutting the pole ear. The size of the first plate portion in the length direction of the battery cell is larger than the size of the second plate portion in the length direction. Compared with the case where the entire bottom plate is a structure of equal thickness, the volume of the bottom plate is reduced, the weight of the entire pole is reduced, and the manufacturing cost of the pole is reduced.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a pole, a cover plate assembly and a battery cell. Background Art

[0002] As lithium-ion battery technology becomes increasingly mature, lithium-ion batteries are widely used as power batteries in electric vehicles and energy storage fields, and the requirements for the performance and safety of lithium-ion batteries are increasing.

[0003] The cover plate of a lithium battery is a key component in a lithium-ion battery. The cover plate can be welded with the shell to form a sealed cavity, lead out the positive and negative electrodes of the electrode group, and serve as an assembly carrier. The cover plate generally includes a riveting block, a second plastic part, a pole, a top cover sheet, a first plastic part, a sealing ring and other structures. During the battery manufacturing process, the Mylar film needs to be wrapped on the outside of both the cover plate and the pole group, and the Mylar film needs to be hot-melted with the first plastic part. In order to ensure that the pole ear will not be cut by the first plastic part, the bottom plate of the pole column needs to be flush with the lower end surface of the first plastic part, which makes the thickness of the bottom plate of the pole column thicker, far exceeding the thickness required for the welding of the pole ear. The manufacturing cost of this pole is high and the weight of the pole is heavy. Summary of the invention

[0004] In view of this, the present application provides a pole, a cover plate assembly and a battery cell to solve the problem that the bottom plate of the pole needs to be flush with the lower end surface of the first plastic part, which makes the thickness of the bottom plate of the pole thicker, far exceeding the thickness required for welding the pole ear. The manufacturing cost of this pole is high and the weight of the pole ear is heavy.

[0005] According to a first aspect of the present application, a pole is provided, which is used for a battery cell. The pole includes a pole body and a bottom plate, the pole body is connected to the bottom plate, the bottom plate includes a first plate portion and a second plate portion, the first plate portion is connected to the second plate portion on one side of the battery cell in a thickness direction, the second plate portion is used to be connected to a pole ear, and the size of the first plate portion in the length direction of the battery cell is larger than the size of the second plate portion in the length direction.

[0006] Preferably, the base plate further includes a third plate portion, the two ends of which in the thickness direction are respectively connected to the first plate portion and the second plate portion, and the dimension of the third plate portion in the length direction gradually decreases in the direction from the first plate portion to the second plate portion.

[0007] Preferably, the third plate portion includes an inclined plane facing away from the pole body, the second plate portion includes a reference plane facing away from the pole body, and an angle between the inclined plane and the reference plane is greater than or equal to 100 degrees and less than or equal to 150 degrees.

[0008] Preferably, a dimension of the third plate portion in a width direction of the battery cell is equal to a dimension of the first plate portion in the width direction, and a dimension of the third plate portion in the width direction is equal to a dimension of the second plate portion in the width direction.

[0009] Preferably, a dimension of the first plate portion in the length direction is a first predetermined dimension, and the first predetermined dimension is greater than or equal to 1 mm and less than or equal to 3 mm.

[0010] Preferably, a dimension of the second plate portion in the length direction is a second predetermined dimension, and the second predetermined dimension is greater than or equal to 0.8 mm and less than or equal to 1.3 mm.

[0011] Preferably, a dimension of the first plate portion in the thickness direction is greater than or equal to 0.5 mm and less than or equal to 1 mm.

[0012] According to a second aspect of the present application, a cover plate assembly is provided, which includes a first plastic part and the above-mentioned pole, wherein the end surface of the first plastic part facing away from the pole body in the length direction is flush with the end surface of the first plate portion facing away from the pole body in the length direction.

[0013] Preferably, the first plastic part includes a main body and a protruding portion, the protruding portion protrudes from the main body, the side of the bottom plate facing the pole body is in contact with the main body, and the end surface of the first plate portion facing away from the pole body is flush with the end surface of the protruding portion facing away from the main body.

[0014] According to a third aspect of the present application, a battery cell is provided, the battery cell comprising a pole group and the above-mentioned cover plate assembly, the pole group comprising a pole ear, and the pole ear is connected to the second plate portion.

[0015] In the pole of the present application, the bottom plate includes a first plate portion and a second plate portion, the first plate portion is connected to the second plate portion on one side in the thickness direction of the battery cell, the second plate portion is used to connect to the pole lug, and the size of the first plate portion in the length direction of the battery cell is larger than the size of the second plate portion in the length direction. In this way, only the first plate portion is flush with the lower end surface of the first plastic part, which can prevent the first plastic part from cutting the pole lug. The size of the first plate portion in the length direction of the battery cell is larger than the size of the second plate portion in the length direction. Compared with the case where the entire bottom plate is a structure of equal thickness, the volume of the bottom plate is reduced, the weight of the entire pole is reduced, and the manufacturing cost of the pole is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 A schematic diagram showing the planar structure of a pole according to an embodiment of the present invention;

[0018] Figure 2 An exploded view of a cover plate assembly showing an embodiment of the present invention;

[0019] Figure 3 A schematic diagram showing a planar structure of a battery cell in an embodiment of the present invention is shown;

[0020] Figure 4 Show Figure 3 Schematic diagram of the partial structure of the cross-section of the battery cell obtained along A-A'.

[0021] Icons: 1-pole; 11-pole body; 12-bottom plate; 121-first plate portion; 122-second plate portion; 123-third plate portion; 2-first plastic part; 21-main body; 211-first through hole; 22-projecting portion; 3-top cover; 31-second through hole; 4-second plastic part; 41-third through hole; 5-connecting piece; 51-fourth through hole; 6-sealing ring; 7-ear; S1-inclined plane; S2-reference plane; L1-thickness direction; L2-length direction; L3-width direction. DETAILED DESCRIPTION

[0022] The following specific embodiments are provided to help the reader obtain a comprehensive understanding of the methods, devices and / or systems described herein. However, after understanding the disclosure of the present application, various changes, modifications and equivalents of the methods, devices and / or systems described herein will be apparent. For example, the order of operations described herein is merely an example, and is not limited to the order set forth herein, but in addition to the operations that must occur in a particular order, changes that will be apparent after understanding the disclosure of the present application may be made. In addition, in order to improve clarity and brevity, descriptions of features known in the art may be omitted.

[0023] The features described herein may be implemented in different forms and should not be interpreted as being limited to the examples described herein. Rather, the examples described herein have been provided only to illustrate some of the many possible ways of implementing the methods, devices and / or systems described herein that will be apparent after understanding the disclosure of the present application.

[0024] Throughout the specification, when an element (such as a layer, a region, or a substrate) is described as being “on”, “connected to”, “bound to”, “over”, or “covering” another element, it may be directly “on”, “connected to”, “bound to”, “over”, or “covering” another element, or one or more other elements may be present between them. In contrast, when an element is described as being “directly on”, “directly connected to”, “directly bound to”, “directly over”, or “directly covering” another element, there may be no other elements present between them.

[0025] As used herein, the term "and / or" includes any one of the associated listed items and any combination of any two or more items.

[0026] Although terms such as "first," "second," and "third" may be used herein to describe various members, components, regions, layers, or portions, these members, components, regions, layers, or portions are not limited by these terms. Rather, these terms are only used to distinguish one member, component, region, layer, or portion from another member, component, region, layer, or portion. Therefore, without departing from the teachings of the examples described herein, the first member, component, region, layer, or portion referred to may also be referred to as the second member, component, region, layer, or portion.

[0027] For ease of description, spatial relational terms such as "above", "upper", "below", and "lower" may be used herein to describe the relationship of one element to another element as shown in the accompanying drawings. Such spatial relational terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the accompanying drawings. For example, if the device in the accompanying drawings is turned over, an element described as being "above" or "upper" relative to another element will subsequently be "below" or "lower" relative to the other element. Therefore, the term "above" includes both "above" and "below" orientations depending on the spatial orientation of the device. The device may also be positioned in other ways (e.g., rotated 90 degrees or in other orientations), and the spatial relational terms used herein will be interpreted accordingly.

[0028] The terms used herein are only used to describe various examples and are not used to limit the present disclosure. Unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. The terms "include", "comprise" and "have" list the stated features, quantities, operations, components, elements and / or their combinations that exist, but do not exclude the existence or addition of one or more other features, quantities, operations, components, elements and / or their combinations.

[0029] Variations in the shapes shown in the drawings may occur due to manufacturing techniques and / or tolerances. Therefore, the examples described herein are not limited to the specific shapes shown in the drawings but include variations in shapes that occur during manufacturing.

[0030] The features of the examples described herein may be combined in various ways that will be apparent after understanding the disclosure of the present application. In addition, although the examples described herein have various configurations, other configurations are possible as will be apparent after understanding the disclosure of the present application.

[0031] The following will be combined Figures 1 to 4 The pole 1, the cover plate assembly and the battery cell of the present application are described. Figures 1 to 4 In the embodiment, the length direction L2 of the battery cell, the width direction L3 of the battery cell and the thickness direction L1 of the battery cell are perpendicular to each other.

[0032] According to a first aspect of the present application, a pole 1 is provided, such as Figure 1 As shown, the pole 1 is used for the battery cell, and the pole 1 includes a pole body 11 and a bottom plate 12. The pole body 11 is connected to the bottom plate 12. The bottom plate 12 includes a first plate portion 121 and a second plate portion 122. The first plate portion 121 and the second plate portion 122 are connected at one side in the thickness direction L1 of the battery cell. The second plate portion 122 is used to connect with the pole lug 7. The size of the first plate portion 121 in the length direction L2 of the battery cell is larger than the size of the second plate portion 122 in the length direction L2. In this way, only the first plate portion 121 can be flush with the lower end surface of the first plastic part 2, which can prevent the first plastic part 2 from cutting the pole lug 7. The size of the first plate portion 121 in the length direction L2 of the battery cell is larger than the size of the second plate portion 122 in the length direction L2. Compared with the case where the entire bottom plate 12 is a structure of equal thickness, the volume of the bottom plate 12 is reduced, the weight of the entire pole 1 is reduced, and the manufacturing cost of the pole 1 is reduced.

[0033] In addition, compared with the bottom plate 12 of the same thickness structure, the volume of the bottom plate 12 in the pole 1 of the present application is reduced, so that the space utilization rate of the battery cell can be improved.

[0034] In the embodiments of the present application, Figure 1As shown, the dimension of the first plate portion 121 in the length direction L2 is a first predetermined dimension a, and the dimension of the second plate portion 122 in the length direction L2 is a second predetermined dimension b.

[0035] Preferably, the first predetermined dimension a is greater than or equal to 1 mm and less than or equal to 3 mm, that is, 1 mm≤a≤3 mm. For example, the first predetermined dimension a can be 1 mm, 1.5 mm, 1.7 mm, 2.0 mm, 2.2 mm, 2.3 mm or 2.5 mm. By setting the dimension of the first plate portion 121 in the thickness direction L1 to the above dimension, the end surface of the first plate portion 121 facing away from the pole body 11 can be flush with the end surface (that is, the lower end surface) of the first plastic part 2 facing away from the pole body 11.

[0036] Preferably, the dimension c of the first plate portion 121 in the thickness direction L1 is greater than or equal to 0.5 mm and less than or equal to 1 mm, that is, 0.5 mm ≤ c ≤ 1 mm. For example, the dimension c of the first plate portion 121 in the thickness direction L1 may be 0.5 mm, 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, 0.8 mm, 0.83 mm, 0.9 mm, 0.96 mm or 1 mm. In this way, the dimension c of the first plate portion 121 in the thickness direction L1 is set to 0.5 mm-1 mm, and the first predetermined dimension a of the first plate portion 121 in the length direction L2 is set to 1 mm-3 mm, which can ensure that the surface of the first plate portion 121 facing away from the pole body 11 has a sufficient area to further prevent the pole ear 7 from being cut by the first plastic part 2.

[0037] Preferably, the second predetermined dimension b is greater than or equal to 0.8 mm and less than or equal to 1.3 mm, that is, 0.8 mm≤b≤1.3 mm, for example, the second predetermined dimension b may be 0.8 mm, 0.9 mm, 1.0 mm, 1.05 mm, 1.1 mm or 1.3 mm, etc. By setting the second predetermined dimension b of the second plate portion 122 in the length direction L2 to the above value, the dimension of the second plate portion 122 in the length direction L2 can be reduced as much as possible while ensuring that the thickness requirement for welding is met, so that the weight of the pole 1 is reduced and the manufacturing cost of the pole 1 is reduced.

[0038] In the embodiments of the present application, Figure 1 As shown, the bottom plate 12 further includes a third plate portion 123, and the two ends of the third plate portion 123 in the thickness direction L1 are connected to the first plate portion 121 and the second plate portion 122 respectively. Figure 4As shown, when the bottom plate 12 is welded to the pole lug 7, the pole lug 7 is bent so that the end surface of the first plate portion 121 facing away from the pole column 11, the end surface of the second plate portion 122 facing away from the pole column 11, and the end surface of the third plate portion 123 facing away from the pole column 11 are respectively fitted with different parts of the pole lug 7. In the direction from the first plate portion 121 to the second plate portion 122, the size of the third plate portion 123 in the length direction L2 is gradually reduced, so that the third plate portion 123 is formed as a transition portion between the first plate portion 121 and the second plate portion 122, which can prevent the pole lug 7 from being damaged by an excessively large bending angle.

[0039] In addition, in the direction from the first plate portion 121 to the second plate portion 122, the size of the third plate portion 123 in the length direction L2 gradually decreases. That is, in the direction from the first plate portion 121 to the second plate portion 122, the distance between the surface of the third plate portion 123 facing the pole body 11 and the surface of the third plate portion 123 facing away from the pole body 11 gradually decreases. Optionally, the surface of the third plate portion 123 facing the pole body 11 is a plane, and the surface of the third plate portion 123 facing away from the pole body 11 is a plane or a curved surface.

[0040] Preferably, the surface of the third plate portion 123 facing away from the pole body 11 is an inclined plane, that is, the surface of the third plate portion 123 facing away from the pole body 11 is an inclined plane S1, and the surface of the second plate portion 122 facing away from the pole body 11 is a reference plane S2, and the angle θ between the inclined plane S1 and the reference plane S2 is greater than or equal to 100 degrees, and less than or equal to 150 degrees, that is, 100 degrees ≤ θ ≤ 150 degrees. When the angle θ between the inclined plane S1 and the reference plane S2 is less than 100 degrees, the pole ear 7 needs to be bent at a larger angle, and the pole ear 7 is damaged, which leads to a greater risk of battery cell failure; when the angle θ between the inclined plane S1 and the reference plane S2 is greater than 150 degrees, the position of the intervention welding is greatly offset toward the center of the pole 1, the current transmission path increases, and the charging and discharging temperature rise of the pole ear 7 is high, which is prone to safety problems. When the angle θ between the inclined plane S1 and the reference plane S2 is greater than or equal to 100 degrees and less than or equal to 150 degrees, the risk of damage to the tab 7 during welding can be reduced while the temperature rise requirement is met.

[0041] In the battery cell, the maximum temperature rise of the tab 7 needs to be less than or equal to 25°C, and the tab 7 cannot be broken. When the angle θ between the inclined plane S1 and the reference plane S2 is greater than or equal to 100 degrees and less than or equal to 150 degrees, the temperature rise of the tab 7 can meet the above standards, and the tab 7 will not be broken. The following will combine Case 1 and Case 2 to analyze the influence of different angles θ between the inclined plane S1 and the reference plane S2 on the temperature rise of the tab 7 and the rupture of the tab 7. Specifically, on the basis of the first predetermined dimension a and the dimension c of the first plate portion 121 in the thickness direction L1, the pole 1 with different angles θ between the inclined plane S1 and the reference plane S2 can be selected for experiment.

[0042] Case 1

[0043] In this case, the first predetermined dimension a is 2 mm, and the dimension c of the first plate portion 121 in the thickness direction L1 is 0.6 mm.

[0044]

[0045] Based on the above-mentioned embodiments 1-6 and comparative examples 1-4, it can be known that when the angle θ between the inclined plane S1 and the reference plane S2 is less than 100 degrees, the temperature rise of the tab 7 is less than 25°C, and the tab 7 is broken; when the angle θ between the inclined plane S1 and the reference plane S2 is greater than 150 degrees, the tab 7 is not broken, and the temperature rise of the tab is greater than 25°C. When the angle θ between the inclined plane S1 and the reference plane S2 is greater than or equal to 100 degrees and less than or equal to 150 degrees, the temperature rise of the tab 7 is less than 25°C, and the tab 7 is not broken.

[0046] Case 2

[0047] In this case, the first predetermined dimension a is 2.3 mm, and the dimension c of the first plate portion 121 in the thickness direction L1 is 0.8 mm.

[0048]

[0049] Based on the above-mentioned embodiments 1-6 and comparative examples 1-4, it can be known that when the angle θ between the inclined plane S1 and the reference plane S2 is less than 100 degrees, the temperature rise of the tab 7 is less than 25°C, and the tab 7 is broken; when the angle θ between the inclined plane S1 and the reference plane S2 is greater than 150 degrees, the tab 7 is not broken, and the temperature rise of the tab is greater than 25°C. When the angle θ between the inclined plane S1 and the reference plane S2 is greater than or equal to 100 degrees and less than or equal to 150 degrees, the temperature rise of the tab 7 is less than 25°C, and the tab 7 is not broken.

[0050] Preferably, the size of the third plate portion 123 in the width direction L3 of the battery cell is equal to the size of the first plate portion 121 in the thickness direction L1, and the size of the third plate portion 123 in the width direction L3 is equal to the size of the second plate portion 122 in the width direction L3, that is, the two ends of the first plate portion 121 in the width direction L3, the two ends of the second plate portion 122 in the width direction L3, and the two ends of the third plate portion 123 in the width direction L3 are all flush.

[0051] It should be noted that the above-mentioned separate descriptions of the first plate portion 121, the second plate portion 122 and the third plate portion 123 are only for the convenience of describing the overall shape of the base plate 12. In the entity of the base plate 12, there may not be any dividing line or interface between the first plate portion 121 and the third plate portion 123, and between the third plate portion 123 and the second plate portion 122. The first plate portion 121, the second plate portion 122 and the third plate portion 123 may be integrally formed.

[0052] In the pole 1 of the present application, by setting the bottom plate 12 to a structure including three parts: a first plate portion 121, a second plate portion 122 and a third plate portion 123, the volume of the bottom plate 12 can be reduced, so that the weight of the entire pole 1 is reduced, the manufacturing cost of the pole 1 is reduced, and at the same time, the space utilization rate of the battery cell where the cover plate assembly including the pole 1 is located can be improved.

[0053] According to a second aspect of the present application, a cover plate assembly is provided, the cover plate assembly comprising a first plastic part 2 and the above-mentioned pole 1. Figure 2 Figure 3 and Figure 4 As shown, the end surface of the first plastic part 2 facing away from the pole body 11 in the length direction L2 is flush with the end surface of the first plate portion 121 facing away from the pole body 11 in the length direction L2, which can prevent the first plastic part 2 from cutting the pole lug 7 connected to the pole 1.

[0054] Furthermore, the main body 21 and the protruding portion 22, the protruding portion 22 protrudes from the main body 21, the side of the bottom plate 12 facing the pole body 11 is in contact with the main body 21, and the end surface of the first plate portion 121 facing away from the pole body 11 is flush with the end surface of the protruding portion 22 facing away from the main body 21, so as to prevent the first plastic part 2 from cutting the pole ear 7 connected to the pole 1. The main body 21 is provided with a first through hole 211, so that the pole body 11 can pass through the main body 21 through the first through hole 211.

[0055] In addition, if Figure 2As shown, the cover plate assembly also includes a sealing ring 6, a top cover sheet 3, a second plastic part 4 and a connecting member 5. The top cover sheet 3, the second plastic part 4 and the connecting member 5 are respectively provided with a second through hole 31, a third through hole 41 and a fourth through hole 51. The top cover sheet 3 is arranged on the side of the main body 21 facing away from the bottom plate 12, the second plastic part 4 is arranged on the side of the top cover sheet 3 facing away from the main body 21, the second plastic part 4 is formed with an installation groove, and the connecting member 5 is arranged in the placement groove. The first through hole 211, the second through hole 31, the third through hole 41 and the fourth through hole 51 are connected, and the sealing ring 6 is sleeved on the pole body 11. The pole body 11 passes through the first through hole 211, the second through hole 31, the third through hole 41 and the fourth through hole 51 in sequence, thereby completing the assembly of the pole body 11.

[0056] Optionally, the top cover sheet 3 may be a plain aluminum sheet.

[0057] In the cover plate assembly of the present application, the first plate portion 121 is flush with the end surface of the protruding portion 22 facing away from the main body 21, and the second plate portion 122 and the third plate portion 123 are recessed relative to the end surface of the protruding portion 22 facing away from the main body 21 toward the side where the main body 21 is located. In this way, the volume of the entire pole is reduced, the weight of the entire pole 1 is reduced, and the manufacturing cost of the pole 1 is reduced.

[0058] According to a third aspect of the present application, a battery cell is provided, such as Figure 4 As shown, the battery cell includes a pole group and the above-mentioned cover plate assembly, the pole group includes a pole ear 7, and the pole ear 7 is welded to the second plate portion 122. In this way, while ensuring that the bottom plate 12 can meet the welding requirements, the volume of the pole 1 is reduced, and the manufacturing cost of the pole 1 is reduced.

[0059] Furthermore, the battery cell also includes a Mylar film and a shell. The Mylar film covers the electrode group and the side of the first plastic part 2. The Mylar film can be hot-fused to the side of the protrusion 22. The electrode group and cover plate assembly covered with the Mylar film can be assembled inside the shell.

[0060] In the battery cell of the present application, the space occupied by the pole 1 inside the shell is reduced, thereby improving the space utilization rate inside the shell.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A pole, which is used for a battery cell, characterized in that: The pole comprises a pole body and a bottom plate, the pole body is connected to the bottom plate, the bottom plate comprises a first plate portion and a second plate portion, the first plate portion is connected to the second plate portion on one side of the thickness direction of the battery cell, the second plate portion is used to connect with the pole ear, and the size of the first plate portion in the length direction of the battery cell is larger than the size of the second plate portion in the length direction; The bottom plate further includes a third plate portion, the two ends of the third plate portion in the thickness direction are respectively connected to the first plate portion and the second plate portion, and the dimension of the third plate portion in the length direction is gradually reduced in the direction from the first plate portion to the second plate portion; The third plate portion includes an inclined plane facing away from the pole body, the second plate portion includes a reference plane facing away from the pole body, and an angle between the inclined plane and the reference plane is greater than or equal to 100 degrees and less than or equal to 150 degrees; The second plate portion is a structure of uniform thickness, and the first plate portion is a structure of uniform thickness; The end surface of the first plate portion facing away from the pole column in the length direction is flush with the end surface of the first plastic part in the cover plate assembly facing away from the pole column in the length direction; The dimension of the first plate portion in the length direction is a first predetermined dimension, and the first predetermined dimension is greater than or equal to 1 mm and less than or equal to 3 mm; The dimension of the second plate portion in the length direction is a second predetermined dimension, and the second predetermined dimension is greater than or equal to 0.8 mm and less than or equal to 1.3 mm; A dimension of the first plate portion in the thickness direction is greater than or equal to 0.5 mm and less than or equal to 1 mm.

2. The pole according to claim 1, characterized in that: The dimension of the third plate portion in the width direction of the battery cell is equal to the dimension of the first plate portion in the width direction, and the dimension of the third plate portion in the width direction is equal to the dimension of the second plate portion in the width direction.

3. A cover plate assembly, characterized in that: The cover plate assembly comprises a first plastic part and the pole according to claim 1 or 2, wherein an end surface of the first plastic part facing away from the pole body in the length direction is flush with an end surface of the first plate portion facing away from the pole body in the length direction.

4. The cover plate assembly according to claim 3, characterized in that: The first plastic part includes a main body and a protruding part, the protruding part protrudes from the main body, the side of the bottom plate facing the pole body is in contact with the main body, and the end surface of the first plate part facing away from the pole body is flush with the end surface of the protruding part facing away from the main body.

5. A battery cell, characterized in that: The battery cell comprises a pole group and the cover plate assembly according to claim 3 or 4, wherein the pole group comprises a pole lug, and the pole lug is connected to the second plate portion.

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