Battery cell cover plate and battery cell

Abstract

The application relates to the technical field of batteries, in particular to a battery cell cover plate and a battery cell. The battery cell cover plate comprises: a liquid injection hole arranged on a cover plate main body; a first insulating piece with a first cavity and a second cavity arranged at intervals along the thickness direction of the cover plate main body; the opening of the first cavity faces the cover plate main body, the opening of the second cavity faces away from the cover plate main body, the cavity bottom of the second cavity is provided with a first through part in communication with the first cavity, and the side wall of the second cavity is provided with a second through part in communication with a pole group; a sealing cover piece is connected with the first insulating piece, the sealing cover piece seals the opening of the second cavity and can abut against the pole group, the application realizes smooth inflow of electrolyte, improves the stability of the battery cell in the process of high-temperature baking and pre-charging, the sealing cover can increase the contact area of the battery cell cover plate and the pole group, the pole group is more safe and stable in the battery cell and is not prone to shaking, and therefore the performance and safety performance of the battery cell are ensured.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a cell cover plate and a cell. Background Technology

[0002] With the increasing maturity of lithium-ion battery technology, lithium-ion batteries are widely used as power batteries in electric vehicles and energy storage, leading to increasingly stringent requirements for their performance and safety. The lithium battery cover is a key component of a lithium-ion battery, serving to form a sealed cavity when welded to the casing, to lead out the positive and negative electrodes, and to act as an assembly carrier.

[0003] Currently, the cover plate mainly consists of a top cover plate, upper plastic, riveting block, electrode post, lower plastic, and sealing ring. The upper surface of the lower plastic is connected to the top cover plate, and the lower surface abuts against the electrode assembly, thereby limiting the electrode assembly. The top cover plate is provided with an injection hole for injecting electrolyte. In order to allow the electrolyte to flow to the electrode assembly, the lower plastic has a dispersion hole at the position corresponding to the injection hole. Because the dispersion hole is located against the electrode assembly, the diaphragm in the electrode assembly can easily block the dispersion hole, making it difficult for the electrolyte to pass through the dispersion hole. This results in reduced electrolyte injection efficiency, increased injection time, and a greater risk of electrolyte overflow. At the same time, during the high-temperature baking and pre-charging processes of the battery cell, the internal gas pressure of the battery cell can increase, causing the dispersion hole to be blocked by the diaphragm. The gas cannot be discharged through the injection hole in time, causing the battery cell to swell, resulting in performance and safety abnormalities. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide a cell cover and a cell to solve the problems of the existing cell cover where the location of the dispersion hole on the lower plastic abuts against the electrode assembly, making it easy for the diaphragm in the electrode assembly to block the dispersion hole, resulting in reduced electrolyte injection efficiency, increased injection time, and a greater risk of electrolyte overflow; and the problem of performance and safety abnormalities caused by increased internal gas pressure in the cell during the high-temperature baking and pre-charging process, where gas cannot be discharged through the injection hole in time.

[0005] A first aspect of the present invention provides a battery cell cover plate, comprising:

[0006] The cover plate body has an injection hole;

[0007] A first insulating element is disposed on the side of the cover plate body facing the inside of the battery cell; the first insulating element has a first cavity and a second cavity spaced apart along the thickness direction of the cover plate body; the opening on the first cavity is disposed on the side of the first insulating element facing the cover plate body and communicates with the liquid injection hole, the opening on the second cavity is disposed on the side of the first insulating element facing away from the cover plate body, the bottom of the second cavity has a first through portion communicating with the first cavity, and the side wall of the second cavity has a second through portion communicating with the electrode assembly;

[0008] A cover is connected to the first insulating member, the cover closing the opening of the second cavity and being able to abut against the electrode assembly.

[0009] Preferably, the cover is embedded in the second cavity, such that the end of the side wall of the second cavity facing the electrode group can abut against the electrode group.

[0010] Preferably, the first insulating member has a limiting protrusion formed on the side facing away from the cover plate body, which can abut against the electrode group, the second cavity is disposed on the limiting protrusion, and the second through portion penetrates through the side wall of the limiting protrusion.

[0011] Preferably, the opening of the second cavity is open on the side facing the second through portion, such that a notch communicating with the second through portion is formed on the opening of the second cavity, the cover is formed as a plate structure and the edge of the cover has a protruding partition to extend into the notch, such that the partition is located on the side of the second through portion facing the pole group in the thickness direction of the cover body.

[0012] Preferably, the interconnecting area of ​​the injection hole is S1, in mm. 2 The connecting area of ​​the first through portion is S2, in mm. 2 S2 / S1≥0.9.

[0013] Preferably, the interconnecting area of ​​the injection hole is S1, in mm. 2 The connecting area of ​​the second through section is S3, in mm. 2 S3 / S1≥0.6.

[0014] Preferably, the axis of the injection hole is not collinear with the axis of the first through portion.

[0015] Preferably, the first insulating member has a first mounting hole for the electrode post to pass through, and the second through portion is formed on the side wall of the second cavity facing the first mounting hole.

[0016] Preferably, the second cavity is provided with a protruding reinforcing part, and the side of the cover facing away from the electrode assembly abuts against the reinforcing part.

[0017] A second aspect of the present invention provides a battery cell, including the battery cell cover plate described in any of the above technical solutions.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] In the battery cell cover plate of the present invention, a liquid injection hole is provided on the cover plate body; a first insulating member is disposed on the side of the cover plate body facing the inside of the battery cell; a first cavity and a second cavity are provided on the first insulating member at intervals along the thickness direction of the cover plate body; an opening on the first cavity is disposed on the side of the first insulating member facing the cover plate body and communicates with the liquid injection hole, and an opening on the second cavity is disposed on the side of the first insulating member facing away from the cover plate body; a first through portion communicating with the first cavity is provided at the bottom of the second cavity, and a second through portion communicating with the electrode assembly is provided on the side wall of the second cavity; a sealing member is connected to the first insulating member, and the sealing member... The second cavity opening is sealed and can abut against the electrode assembly. This second through-hole design ensures smooth electrolyte flow, thereby improving electrolyte injection efficiency, reducing injection time and the risk of electrolyte overflow. It also improves the stability of the cell during high-temperature baking and pre-charging processes, allowing gas to be discharged through the injection hole in a timely manner, preventing cell bulging. This significantly improves abnormal problems caused by internal and external pressure differences during the cell manufacturing process. In addition, the cap increases the contact area between the cell cover and the electrode assembly, making the electrode assembly safer and more stable inside the cell, less prone to shaking, thus ensuring cell performance and safety.

[0020] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of the battery cell cover plate provided in an embodiment of the present invention;

[0023] Figure 2 For along Figure 1 Cross-sectional view taken at point AA in the middle;

[0024] Figure 3This is a schematic diagram of the battery cell cover plate provided in an embodiment of the present invention from another perspective;

[0025] Figure 4 This is a schematic diagram of the assembly structure of the first insulating component and the sealing component in the battery cell cover plate provided in an embodiment of the present invention;

[0026] Figure 5 This is an exploded view of the assembly of the first insulating component and the sealing component in the battery cell cover provided in an embodiment of the present invention;

[0027] Figure 6 This is a schematic diagram of the structure of the first insulating element in the battery cell cover provided in an embodiment of the present invention;

[0028] Figure 7 A schematic diagram of the structure of the first insulating element in the cell cover plate provided in an embodiment of the present invention from another perspective;

[0029] Figure 8 This is a cross-sectional view of the structure of the first insulating element in the battery cell cover provided in an embodiment of the present invention.

[0030] Icons: 10-Cover plate body; 11-Injection hole; 20-First insulating component; 21-First cavity; 22-Second cavity; 221-Notch; 23-First through part; 24-Second through part; 25-Limiting protrusion; 26-Reinforcing part; 27-First mounting hole; 30-Sealing component; 31-Separating part; 40-Second insulating component; 50-Pole post; 60-Sealing component; 70-Mounting component; D1-First direction; D2-Second direction. Detailed Implementation

[0031] The following detailed embodiments are provided to help the reader gain a comprehensive understanding of the methods, apparatus, and / or systems described herein. However, various changes, modifications, and equivalents of the methods, apparatus, and / or systems described herein will be apparent after understanding the disclosure of this application. For example, the order of operations described herein is merely illustrative and is not limited to the order set forth herein; changes that will be apparent after understanding the disclosure of this application are possible, except for operations that must occur in a specific order. Furthermore, for clarity and brevity, descriptions of features known in the art may be omitted.

[0032] The features described herein may be implemented in different forms and should not be construed as being limited to the examples described herein. Rather, the examples described herein have been provided merely to illustrate some of the many feasible ways of implementing the methods, apparatus, and / or systems described herein that will be apparent upon understanding the disclosure of this application.

[0033] Throughout the specification, when an element (such as a layer, region, or substrate) is described as being "on" another element, "connected to" another element, "bonded to" another element, "on" another element, or "covering" another element, it may be directly "on" another element, "connected to" another element, "bonded to" another element, "on" another element, or "covering" another element, or there may be one or more other elements in between. In contrast, when an element is described as being "directly on" another element, "directly connected to" another element, "directly bonded to" another element, "directly on" another element, or "directly covering" another element, there may be no other elements in between.

[0034] As used herein, the term “and / or” includes any one of the relevant items listed and any combination of any two or more items.

[0035] Although terms such as “first,” “second,” and “third” may be used herein to describe individual components, assemblies, regions, layers, or parts, these components, assemblies, regions, layers, or parts are not limited by these terms. Rather, these terms are used only to distinguish one component, assembly, region, layer, or part from another. Therefore, without departing from the teachings of the examples described herein, the first component, assembly, region, layer, or part referred to as the second component, assembly, region, layer, or part may also be referred to as the second component, assembly, region, layer, or part.

[0036] For ease of description, spatial relation terms such as “above,” “upper,” “below,” and “lower” are used herein to describe the relationship between one element and another, as shown in the accompanying drawings. Such spatial relation terms are intended to include not only the orientation depicted in the drawings but also different orientations of the device during use or operation. For example, if the device in the drawings is flipped, an element described as being “above” or “upper” relative to another element will subsequently be “below” or “lower” relative to that 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 relation terms used herein will be interpreted accordingly.

[0037] The terminology used herein is for the purpose of describing various examples only and is not intended to limit this disclosure. Unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. The terms “comprising,” “including,” and “having” enumerate the stated features, quantities, operations, components, elements, and / or combinations thereof, but do not exclude the presence or addition of one or more other features, quantities, operations, components, elements, and / or combinations thereof.

[0038] Variations in the shapes shown in the accompanying 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 accompanying drawings, but include changes in shape that may occur during manufacturing.

[0039] The features of the examples described herein can be combined in various ways that will be apparent upon understanding the disclosure of this application. Furthermore, although the examples described herein have a wide variety of constructions, other constructions are possible, as will be apparent upon understanding the disclosure of this application.

[0040] According to a first aspect of the present invention, a battery cell cover plate is provided, which includes a cover plate body 10, a first insulating member 20, and a sealing member 30.

[0041] The specific structure of the above-described components of the cell cover plate according to this embodiment will be described below.

[0042] In this embodiment, as Figure 1 and Figure 2 As shown, the cover plate body 10 has an injection hole 11. The cover plate body 10 is formed into a plate-shaped structure. When the battery cell is a square-shell battery cell or a blade battery cell, the cover plate body 10 is a rectangular plate-shaped structure; when the battery cell is a cylindrical battery cell, the cover plate body 10 is a circular plate-shaped structure. The injection hole 11 is a through hole that penetrates the cover plate body 10. The first insulating member 20 is disposed inside the battery cell. Specifically, the first insulating member 20 is disposed on the side of the cover plate body 10 facing the inside of the battery cell, that is, the first insulating member 20 is attached to the surface of the cover plate body 10 facing the inside of the battery cell.

[0043] like Figure 2 , Figures 4 to 8As shown, the first insulating member 20 has a first cavity 21 and a second cavity 22 spaced apart along the thickness direction of the cover plate body 10, that is, the first cavity 21 and the second cavity 22 are arranged vertically along the thickness direction of the cover plate body 10. Specifically, the opening on the first cavity 21 is located on the side of the first insulating member 20 facing the cover plate body 10 and communicates with the injection hole 11, and the opening on the second cavity 22 is located on the side of the first insulating member 20 away from the cover plate body 10. That is, the first cavity 21 is formed by the inward recess of the surface of the first insulating member 20 facing the cover plate body 10, and the second cavity 22 is formed by the inward recess of the surface of the first insulating member 20 away from the cover plate body 10. The bottom of the second cavity 22 has a first through portion 23 communicating with the first cavity 21, and the first through portion 23 is a through hole structure. The side wall of the second cavity 22 has a second through portion 24 communicating with the electrode assembly. That is, the second through portion 24 is formed by the second cavity 22. The sidewall of body 22 extends to the outside of the second cavity 22. The cover 30 is formed as a plate or sheet structure and is connected to the first insulating member 20. The cover 30 closes the opening of the second cavity 22 and can abut against the electrode group. This allows the electrolyte injected through the injection hole 11 to flow into the electrode group sequentially through the first cavity 21, the first through-hole 23, the second cavity 22 and the second through-hole 24, ensuring smooth electrolyte flow, thereby improving the efficiency of electrolyte injection, reducing injection time and the risk of electrolyte overflow, and improving the stability of gas timely discharge through the injection hole 11 during the high-temperature baking and pre-charging process of the cell, avoiding cell swelling. This significantly improves the abnormal problems caused by internal and external pressure differences during the cell manufacturing process. In addition, the cover can increase the contact area between the cell cover plate and the electrode group, making the electrode group safer and more stable inside the cell and less prone to shaking, thereby ensuring the cell performance and safety performance.

[0044] In this embodiment, the first through-hole 23 penetrates the bottom of the second cavity 22 and the second through-hole 24 penetrates the side wall of the second cavity 22, so that the through-hole directions of the first through-hole 23 and the second through-hole 24 are set at an angle, thereby realizing that the communication path between the injection hole 11 and the electrode group is bent, thus buffering the impact of the electrolyte on the electrode group, thereby improving the damage to the electrode group or the electrode tab.

[0045] In this embodiment, both the cover 30 and the first insulating member 20 are made of insulating material, such as PP (polypropylene).

[0046] Optionally, the cover 30 is snapped into the first insulating member 20; or the cover 30 is heat-fused to the first insulating member 20.

[0047] In a preferred embodiment, such as Figures 2 to 5As shown, the cover 30 is embedded in the second cavity 22, so that the surface of the cover 30 facing the electrode group does not protrude from the second cavity 22. This allows the end of the side wall of the second cavity 22 facing the electrode group to also abut against the electrode group, thereby enabling both the cover 30 and the first insulating member 20 to abut against the electrode group. This further increases the area of ​​the contact area between the cell cover and the electrode group, thereby reducing the risk of the electrode group shaking inside the cell.

[0048] In an embodiment, such as Figures 2 to 5 As shown, a limiting protrusion 25 is formed on the side of the first insulating member 20 facing away from the cover plate body 10, which can abut against the electrode assembly, such that the main body of the first insulating member 20 and the main body of the electrode assembly are spaced apart in the thickness direction of the cover plate body 10, and a space for accommodating the electrode tab is formed between them. The second cavity 22 is disposed on the limiting protrusion 25, that is, the second cavity 22 is formed by recessing inward from the side of the limiting protrusion 25 facing the electrode assembly, such that the opening of the second cavity 22 is disposed on the side of the limiting protrusion 25 facing the electrode assembly; the second through portion 24 penetrates through the side wall of the limiting protrusion 25.

[0049] In an alternative embodiment, the second through portion 24 is formed as a through hole structure that is independently provided from the opening of the second cavity 22, so that the second through portion 24 is not connected to the opening of the second cavity 22.

[0050] In a preferred embodiment, such as Figure 5 , Figure 6 and Figure 8 As shown, the opening of the second cavity 22 is open on the side facing the second through portion 24, so that a notch 221 communicating with the second through portion 24 is formed on the opening of the second cavity 22, that is, the opening of the second cavity 22 is formed as a non-closed annular structure; the cover 30 is formed as a plate structure and the edge of the cover 30 is formed with a protruding partition 31. The partition 31 can be a block structure, so that it can extend into the notch 221. In this way, in the thickness direction of the cover plate body 10, the partition 31 is set on the side of the second through portion 24 facing the electrode group, thereby separating the outlet side of the first insulating member 20 for electrolyte entry (i.e., the inlet side for gas discharge) from the electrode group, thereby reducing the risk of low liquid injection efficiency and inability to vent smoothly due to diaphragm blockage on the electrode group.

[0051] In a preferred embodiment, the interconnecting area of ​​the injection hole 11 is S1, in mm. 2 That is, the effective area on the injection hole 11 that enables communication between the inside and outside of the battery cell is S1. For example, when the injection hole 11 is a stepped hole, the area at the smallest diameter point on the stepped hole is S1. Figure 2 As shown, S1 = π (d / 2) 2d is the minimum diameter of the injection hole 11, in mm; the connecting area of ​​the first through-hole 23 is S2, in mm. 2 ,like Figure 7 As shown, S2=πr 2 r is the radius of the first through-hole 23 when the first through-hole 23 is circular, in mm; S2 / S1≥0.9, thus ensuring that the abnormal situation of pressure difference between the inside and outside of the cell is improved during the cell manufacturing process.

[0052] Furthermore, the connecting area of ​​the second through section 24 is S3, in mm. 2 ;like Figure 4 and Figure 7 As shown, S3 = m × h, where h is the height of the second through part 24 in the thickness direction of the cover plate after the cover part 30 is assembled, in mm, and m is the length of the second through part 24 in the second direction D2, in mm; S3 / S1≥0.6, thus further ensuring the improvement of abnormal internal and external pressure differences in the battery cell during the battery cell manufacturing process.

[0053] The following tests were conducted on the internal and external pressure differences during the manufacturing process of battery cells with different interconnection areas to verify the reliability of the constraints S2 / S1≥0.9 and S3 / S1≥0.6. In this embodiment, an internal and external pressure difference ≤20kPa meets the battery cell manufacturing requirements, indicating that the battery cell electrolyte injection and venting are normal. The test results are shown in Table 1.

[0054] Table 1

[0055]

[0056] In a preferred embodiment, such as Figure 1 and Figure 2 As shown, the axis of the injection hole 11 is not collinear with the axis of the first through portion 23, thus enabling the first cavity 21 to provide a certain buffering effect on the electrolyte during the injection process. Specifically, the axis of the injection hole 11 and the axis of the first through portion 23 are staggered in the first direction D1. Preferably, the projection of the first through portion 23 on the cover plate body 10 coincides with the injection hole 11. Optionally, the projection of the first through portion 23 on the cover plate body 10 is spaced apart from the injection hole 11.

[0057] In this embodiment, the first direction D1, the second direction D2 and the thickness direction of the cover plate body 10 are arranged perpendicularly to each other. When the cover plate body 10 has a rectangular plate structure, the first direction D1 is the length direction of the cover plate body 10 and the second direction D2 is the width direction of the cover plate body 10.

[0058] In an embodiment, such as Figures 4 to 8As shown, the first insulating member 20 has a first mounting hole 27 for the electrode post 50 to pass through, and the second through portion 24 is formed on the side wall of the second cavity 22 facing the first mounting hole 27. Specifically, as shown... Figure 7 As shown, in the first direction D1, the second through portion 24 is disposed between the first mounting hole 27 and the first through portion 23, thereby preventing the cell housing from affecting the flow rate of fluid passing through the second through portion 24 after the cell cover plate is assembled with the cell housing.

[0059] In a preferred embodiment, such as Figures 4 to 8 As shown, a protruding reinforcing portion 26 is provided inside the second cavity 22. The side of the cap 30 facing away from the electrode assembly abuts against the reinforcing portion 26. This restricts the position of the cap 30 in the second cavity 22, ensuring the reliability of the cap 30's contact with the electrode assembly to limit its position. It also serves as a guide within the second cavity 22, facilitating the connection between the first through portion 23 and the second through portion 24. The reinforcing portion 26 can be formed as a strip structure, preferably a bent strip structure, to increase the contact area between the reinforcing portion 26 and the cap 30, thereby improving the support effect on the cap 30.

[0060] Furthermore, in this embodiment, such as Figures 1 to 3 As shown, the cell cover also includes a pole post 50, a sealing element 60, a mounting element 70, and a second insulating element 40. The pole post 50 includes a base plate and a connecting post. The connecting post on the pole post 50 passes sequentially from one side inside the cell through the first mounting hole 27 and the through holes on the cover body 10 and the second insulating element 40, and is riveted and / or welded to the mounting element 70 to fix the pole group to the cell cover. The first insulating element 20 is sandwiched between the base plate of the pole post 50 and the cover body 10, and the second insulating element 40 is sandwiched between the cover body 10 and the base plate of the pole post 50. Between the mounting component 70 and the cover plate body 10, an insulating protection is formed; the sealing component 60 can be a fluororubber sealing ring. The sealing component 60 is sleeved on the connecting post of the pole post 50 and passes through the first mounting hole 27 and the through hole on the cover plate body 10 together with the connecting post. Part of the sealing component 60 is sandwiched between the bottom plate of the pole post 50 and the cover plate body 10, and part of the sealing component 60 is sandwiched between the bottom plate of the pole post 50 and the second insulating component 40, so that the sealing component 60 generates a compression amount to ensure the sealing performance of the cell cover plate.

[0061] According to the present invention, a battery cell cover plate is provided, wherein a liquid injection hole 11 is provided on the cover plate body 10; a first insulating member 20 is disposed on the side of the cover plate body 10 facing the inside of the battery cell; a first cavity 21 and a second cavity 22 are provided on the first insulating member 20 at intervals along the thickness direction of the cover plate body 10; an opening on the first cavity 21 is disposed on the side of the first insulating member 20 facing the cover plate body 10 and communicating with the liquid injection hole 11, and an opening on the second cavity 22 is disposed on the side of the first insulating member 20 facing away from the cover plate body 10; a first through portion 23 communicating with the first cavity 21 is provided at the bottom of the second cavity 22, and a second through portion 24 communicating with the electrode assembly is provided on the side wall of the second cavity 22. The cover 30 is connected to the first insulating member 20. The cover 30 closes the opening of the second cavity 22 and can abut against the electrode group. Thus, the setting of the second through part 24 ensures smooth electrolyte flow, thereby improving the efficiency of electrolyte injection, reducing the injection time and the risk of electrolyte overflow, and improving the stability of the cell under high temperature baking and pre-charging process, so as to prevent the cell from swelling. This significantly improves the abnormal problems caused by internal and external pressure difference during the cell manufacturing process. In addition, the cover can increase the contact area between the cell cover plate and the electrode group, making the electrode group safer and more stable inside the cell and less prone to shaking, thereby ensuring the cell performance and safety performance.

[0062] The present invention provides a battery cell comprising the battery cell cover plate as described above, and thus possesses all the beneficial effects of a battery cell cover plate, which will not be repeated here.

[0063] Finally, it should be noted that the above-described embodiments are merely specific implementations of this application, used to illustrate the technical solutions of this application, and not to limit them. The protection scope of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the technical scope disclosed in this application. Such modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be covered within the protection scope of this application. Therefore, the protection scope of this application should be determined by the protection scope of the claims.

Claims

1. A battery cell cover plate, characterized in that, include: The cover plate body has an injection hole; A first insulating element is disposed on the side of the cover plate body facing the inside of the battery cell; the first insulating element has a first cavity and a second cavity spaced apart along the thickness direction of the cover plate body; the opening on the first cavity is disposed on the side of the first insulating element facing the cover plate body and communicates with the liquid injection hole, the opening on the second cavity is disposed on the side of the first insulating element facing away from the cover plate body, the bottom of the second cavity has a first through portion communicating with the first cavity, and the side wall of the second cavity has a second through portion communicating with the electrode assembly; A cover is connected to the first insulating member, the cover closing the opening of the second cavity and being able to abut against the electrode assembly.

2. The cell cover plate according to claim 1, characterized in that, The cover is embedded in the second cavity, so that the end of the side wall of the second cavity facing the electrode group can abut against the electrode group.

3. The cell cover plate according to claim 1, characterized in that, The first insulating member has a limiting protrusion on the side facing away from the cover plate body that can abut against the electrode group, the second cavity is disposed on the limiting protrusion, and the second through portion penetrates the side wall of the limiting protrusion.

4. The cell cover plate according to claim 1, characterized in that, The opening of the second cavity is open on the side facing the second through portion, so that a notch communicating with the second through portion is formed on the opening of the second cavity. The cover is formed as a plate structure and the edge of the cover has a protruding partition to extend into the notch, so that the partition is located on the side of the second through portion facing the pole group in the thickness direction of the cover body.

5. The cell cover plate according to claim 1, characterized in that, The interconnecting area of ​​the injection hole is S1, in mm. 2 The connecting area of ​​the first through portion is S2, in mm. 2 S2 / S1≥0.

9.

6. The cell cover plate according to claim 1, characterized in that, The interconnecting area of ​​the injection hole is S1, in mm. 2 The connecting area of ​​the second through section is S3, in mm. 2 S3 / S1≥0.

6.

7. The cell cover plate according to claim 1, characterized in that, The axis of the injection hole is not collinear with the axis of the first through portion.

8. The cell cover plate according to claim 1, characterized in that, The first insulating member has a first mounting hole for the electrode post to pass through, and the second through portion is formed on the side wall of the second cavity facing the first mounting hole.

9. The cell cover plate according to claim 1, characterized in that, The second cavity is provided with a protruding reinforcing part, and the side of the cover facing away from the electrode assembly abuts against the reinforcing part.

10. A battery cell, characterized in that, The cell cover plate included in any one of claims 1 to 9.

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