Battery cell cover plate and battery cell

Abstract

The invention relates to the technical field of energy storage equipment, in particular to a battery cell cover plate and a battery cell, the battery cell cover plate comprises an insulating part, the insulating part is provided with M protruding parts, the M protruding parts are arranged in a protruding mode towards a pole group, the first end face of each protruding part abuts against the second end face of the pole group, the side edge of the first end face is provided with a recess to form a step face, and the step face is provided with a plurality of grooves. At least part of the step surface is arranged corresponding to the edge and the corner of the second end surface, and M is a positive integer. The battery cell comprises a pole group, a shell and the battery cell cover plate, the battery cell cover plate covers the opening of the shell in a sealing manner, and the pole group is arranged in a cavity defined by the shell. The battery cell cover plate and the battery cell are helpful for preventing the edges and the corners of the pole groups from being crushed by the insulating parts, and have higher process yield and safety performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy storage devices, and particularly relates to a cell cover plate and a cell. BACKGROUND

[0002] The cell has a cover plate structure, which comprises a top cover sheet, a pole and an insulating piece. The insulating piece is used to prevent the top cover sheet made of metal material of the cover plate structure from being in conduction with the pole. The insulating piece is attached to the inner side of the top cover sheet, and the side of the insulating piece away from the top cover sheet is pressed against the end face of the pole group. In the process of the pole group entering the shell, the insulating piece needs to press against the end face of the pole group to push the pole group into the shell. When the finished cell is in the environment of vibration, impact and the like, and the pole group moves in the shell, the acting force between the insulating piece and the pole group will also increase. In the above case, the edges and corner portions of the pole group are often pressed by the insulating piece, which affects the process yield and safety performance of the cell. SUMMARY

[0003] An object of the present application is to provide a cell cover plate, which can help to prevent the edges and corner portions of the pole group from being pressed by the insulating piece, and improve the process yield and safety performance of the cell.

[0004] To achieve the above object, the present application adopts the following technical scheme:

[0005] The present application provides a cell cover plate, which comprises an insulating piece, the insulating piece has M protruding portions, the M protruding portions are all protrudingly arranged towards the pole group, the side edge of the first end face has a recess to form a stepped surface, at least part of the stepped surface is arranged corresponding to the edges and corner portions of the second end face, and M is a positive integer.

[0006] Optionally, each protruding portion is divided into a first portion and a second portion along the plane where the stepped surface is located, the first portion has the first end face, and along the direction perpendicular to the first end face, the height h1 of the first portion satisfies: 1mm≤h1≤2.5mm.

[0007] Optionally, along the direction perpendicular to the first end face, the height H of the protruding portion satisfies: 5mm≤H≤7.5mm.

[0008] Optionally, each protruding portion is divided into a first portion and a second portion along the plane where the stepped surface is located, the first portion has the first end face, and along the direction perpendicular to the first end face, the height h2 of the second portion satisfies: 3mm≤h2≤6mm.

[0009] Optionally, the stepped surface of each protruding portion is annularly arranged along the circumference of the first end face.

[0010] Optionally, the sum of the areas of the M first end faces is S1, the sum of the areas of the faces surrounded by the outer edges of the step faces of the M protrusions is S2, and 0.65≤S1 / S2≤0.9 is satisfied.

[0011] Optionally, the sum of the areas of the M first end faces is S1, the area of the second end face is S3, and 0.2≤S1 / S3≤0.35 is satisfied.

[0012] Optionally, M is 2, and the two protrusions are respectively arranged at the two ends in the length direction of the insulating member.

[0013] Optionally, the edge of the first end face has a transition curved surface.

[0014] Another object of the present application is to provide a battery cell, which helps to prevent the edges and corners of the pole group from being crushed by the insulating member, and improves the process yield and safety performance of the battery cell.

[0015] To achieve the above object, the present application adopts the following technical solutions:

[0016] The present application provides a battery cell, which comprises a pole group, a shell, and the battery cell cover plate described above, the battery cell cover plate is sealingly arranged at the opening of the shell, and the pole group is arranged in the cavity surrounded by the shell.

[0017] The present application has the following advantages:

[0018] The present application provides a battery cell cover plate, which comprises an insulating member, the insulating member has M protrusions, the M protrusions are all arranged protruding towards the pole group, the first end face of each protrusion abuts against the second end face of the pole group, the side edge of the first end face has a recess to form a step face, at least part of the step face is arranged corresponding to the edge and corner of the second end face, and M is a positive integer. By opening the avoiding groove on the protrusion of the insulating member, the edge and corner of the second end face of the pole group can be avoided, and the edge and corner of the pole group can be prevented from being crushed by the insulating member, thereby improving the process yield and safety performance of the battery cell.

[0019] The present application also provides a battery cell, which comprises a pole group, a shell, and the battery cell cover plate described above, the battery cell cover plate is sealingly arranged at the opening of the shell, and the pole group is arranged in the cavity surrounded by the shell. The battery cell helps to prevent the edges and corners of the pole group from being crushed by the insulating member, and improves the process yield and safety performance of the battery cell. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a partial structure schematic diagram of the battery cell provided by the embodiment of the present application;

[0021] Figure 2 is a structure schematic diagram of the battery cell cover plate provided by the embodiment of the present application from the first perspective;

[0022] Figure 3 is a structural schematic view of a second perspective of the battery cell cover plate provided by an embodiment of the present application;

[0023] Figure 4 is a structural schematic view of a third perspective of the battery cell cover plate provided by an embodiment of the present application.

[0024] in the figure:

[0025] 1, insulating part; 11, protrusion; 111, first end surface; 112, step surface; 113, transition curved surface; 1101, first part; 1102, second part;

[0026] 2, first top cover piece;

[0027] 100, battery cell cover plate; 200, pole group; 201, second end surface; 300, end plate; 400, second top cover piece. DETAILED DESCRIPTION

[0028] The technical solutions of the present application are further described below in conjunction with the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are merely used to explain the present application, and not to limit the present application. In addition, it should be noted that, for the convenience of description, only the parts related to the present application are shown in the drawings, not all.

[0029] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be understood broadly, for example, it can be fixed connection, or detachable connection; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0030] In the present application, unless otherwise explicitly specified and limited, the "upper" or "lower" of the first feature to the second feature can include the direct contact of the first and second features, or the indirect contact of the first and second features through another feature between them. Moreover, the "upper", "above" and "on" of the first feature to the second feature includes the vertical direction of the first feature above and oblique above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The "lower", "below" and "under" of the first feature to the second feature includes the vertical direction of the first feature below and oblique below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0031] The electric core has a cover plate structure, which includes a top cover sheet, a pole and an insulating piece. The insulating piece is used to prevent the top cover sheet and the pole from being in conductive short circuit. The insulating piece is attached to the inner side of the top cover sheet, and the side of the insulating piece away from the top cover sheet is pressed against the end surface of the pole group. During the process of the pole group entering the shell, the insulating piece needs to press against the end surface of the pole group to push the pole group into the shell. When the finished electric core is in the environment of vibration, impact and the like, the pole group moves in the shell, and the acting force between the insulating piece and the pole group also increases. In the above case, the edge and the corner of the pole group are often pressed by the insulating piece, which affects the process yield and safety performance of the electric core.

[0032] Therefore, the electric core cover plate 100 is provided to solve the above problems, which helps to prevent the edge and the corner of the pole group 200 from being pressed by the insulating piece 1, and improves the process yield and safety performance of the electric core.

[0033] As shown in Figures 1-4 The electric core cover plate 100 of the embodiment includes an insulating piece 1, which has M protruding parts 11. The M protruding parts 11 are all protruding towards the pole group 200. The first end surface 111 of each protruding part 11 is pressed against the second end surface 201 of the pole group 200. The side of the first end surface 111 has a recess to form a stepped surface 112. At least part of the stepped surface 112 is arranged corresponding to the edge and the corner of the second end surface 201. M is a positive integer. Optionally, the insulating piece 1 is a lower plastic. It should be noted that, along the thickness direction of the insulating piece 1, the area range of the protruding part 11 extends to the end surface of the insulating piece 1 contacting the first top cover sheet 2.

[0034] The electric core cover plate 100 can avoid the edge and the corner of the second end surface 201 of the pole group 200 by opening the avoiding groove on the protruding part 11 of the insulating piece 1, which can prevent the edge and the corner of the pole group 200 from being pressed by the insulating piece 1, and improve the process yield and safety performance of the electric core.

[0035] Optionally, the step surface 112 of each protrusion 11 is arranged along the circumference of the first end face 111. Optionally, the plane on which the root of the protrusion 11 is located, the step surface 112, and the first end face 111 are parallel to each other and are all parallel to the second end face 201. The parallelism between the first end face 111 and the second end face 201 ensures that the first end face 111 is in contact with the second end face 201, maximizing the contact area and ensuring that the insulating member 1 presses and secures the pole group 200. The parallelism between the step surface 112 and the first end face 111 ensures that the distance between the step surface 112 and the plane on which the first end face 111 is located is consistent at all locations along the circumference of the first end face 111. The parallelism between the plane on which the root of the protrusion 11 is located and the first end face 111 ensures that the thickness of the protrusion 11 is consistent at all locations, and the structural strength is balanced at all locations. Optionally, in this embodiment, the plane on which the root of the protrusion 11 is located is the end face of the insulating member 1 facing away from the pole group 200.

[0036] like Figure 4 As shown, optionally, each protrusion 11 is divided into a first portion 1101 and a second portion 1102 along the plane where the step surface 112 is located. The first portion 1101 has a first end surface 111. In the direction perpendicular to the first end surface 111, the height h1 of the first portion 1101 satisfies: 1mm≤h1≤2.5mm. If the height h1 of the first portion 1101 is less than 1mm, the height of the avoidance groove is insufficient. When the first end surface 111 presses against the second end surface 201 of the electrode group 200, the step surface 112 will still contact the edge and corner of the second end surface 201 of the electrode group 200, causing the edge and corner of the second end surface 201 of the electrode group 200 to be crushed. If the height h1 of the first portion 1101 is greater than 2.5mm, then when the overall height of the protrusion 11 is constant, the height of the first portion 1101 is too large and the height of the second portion 1102 will be insufficient. Furthermore, the inner insulating film of the electrode assembly 200 needs to be fixed to the insulating member 1 by heat-melting to ensure overall insulation. If the inner insulating film is heat-melted to the sidewall of the first portion 1101, a portion of the inner insulating film will be tilted, extending from the outer sidewall of the electrode assembly 200 to the inner sidewall of the first portion 1101, making it easy for the heat-melted portion of the inner insulating film and the first portion 1101 to be pulled apart. Therefore, heat-melting the inner insulating film to the sidewall of the second portion 1102 can reduce the tilt angle of the inner insulating film. Alternatively, if the edge of the second end face 201 completely corresponds to the outer edge of the step surface 112, the inner insulating film does not need to be tilted, thus preventing the heat-melted portion between the inner insulating film and the second portion 1102 from being pulled apart. Therefore, the height of the second portion 1102 cannot be too small, otherwise it will limit the heat-melting area. On the one hand, this will increase the difficulty of heat-melting between the inner insulating film and the sidewall of the second portion 1102. On the other hand, the reduced heat-melting area will also affect the connection strength between the two, increasing the risk of the heat-melting portion being pulled apart when subjected to external force.

[0037] Optionally, the height H of the protrusion 11 along a direction perpendicular to the first end face 111 satisfies the following: 5 mm ≤ H ≤ 7.5 mm. The protrusion 11 is not provided where the tabs of the electrode assembly 200 need to be accommodated. Therefore, if the height H of the protrusion 11 is less than 5 mm, the height to accommodate the tabs is insufficient. If the height H of the protrusion 11 is greater than 7.5 mm, the insulating member 1 takes up too much height space within the cell cavity, which is not conducive to improving the volumetric energy density of the cell.

[0038] Optionally, in this embodiment, since the root of the protrusion 11 is the end surface of the insulating member 1 attached to the first top cover sheet 2 , the height H of the protrusion 11 is the entire thickness of the insulating member 1 .

[0039] Optionally, along the direction perpendicular to the first end face 111, the height h2 of the second portion 1102 satisfies: 3mm≤h2≤6mm. If the height h2 of the second portion 1102 is less than 3mm, the sidewall area of ​​the second portion 1102 is too small, and the heat-melting area between the sidewall of the second portion 1102 and the inner insulating film will be insufficient. If the height h2 of the second portion 1102 is greater than 6mm, then when the overall height of the protrusion 11 is constant, the height of the first portion 1101 will be too small, that is, the height of the avoidance groove is insufficient. When the first end face 111 presses against the second end face 201 of the electrode group 200, the step surface 112 will still contact the edge and corner of the second end face 201 of the electrode group 200, causing the edge and corner of the second end face 201 of the electrode group 200 to be crushed.

[0040] Optionally, the sum of the areas of the M first end surfaces 111 is S1, that is, if there are two protrusions 11, the sum of the areas of the first end surface 111 of the first protrusion 11 and the first end surface 111 of the second protrusion 11 is S1. The sum of the areas of the surface enclosed by the outer edges of the step surfaces 112 of the M protrusions 11 is S2. Since the step surface 112 and the first end surface 111 are both parallel to the plane where the root of the protrusion 11 is located, the area of ​​the surface enclosed by the outer edges of the step surface 112 of the protrusion 11 is the sum of the areas of the step surface 112 and the first end surface 111. That is, if there are two protrusions 11, the sum of the areas of the first end surface 111 and the step surface 112 of the first protrusion 11 plus the sum of the areas of the first end surface 111 and the step surface 112 of the second protrusion 11 is S2. Therefore, the ratio of S1 to S2 can be regarded as the average of the proportions of the first end surface 111 of the plurality of protrusions 11 to the common end surface of the first end surface 111 and the step surface 112. S1 and S2 satisfy: 0.65≤S1 / S2≤0.9.

[0041] When the ratio of S1 to S2 is less than 0.65 and the sum of the areas of the first end face 111 and the step face 112 is constant, the proportion of the first end face 111 is too small, the contact area between the first end face 111 and the second end face 201 of the pole piece 200 is insufficient, which can cause the stress of the second end face 201 of the pole piece 200 to be too concentrated, easily causing the second end face 201 to be crushed, and in addition, the insufficient contact area between the first end face 111 and the second end face 201 of the pole piece 200 can also cause the fixing effect of the protruding portion 11 on the pole piece 200 to be insufficient, and the pole piece 200 has a risk of displacement in the direction parallel to the first end face 111, which is not conducive to ensuring the quality of the battery cell.

[0042] When the ratio of S1 to S2 is greater than 0.9 and the sum of the areas of the first end face 111 and the step face 112 is constant, the proportion of the first end face 111 is too large, at this time, the contact area between the first end face 111 and the second end face 201 can be ensured to be large enough, but the edge of the first end face 111 is still very close to the edge and corner of the pole piece 200, and when there are machining errors and assembly errors, the first end face 111 is still easy to crush the edge and corner of the pole piece 200.

[0043] Optionally, the sum of the areas of the M first end faces 111 is S1, that is, if there are two protruding portions 11, the sum of the area of the first end face 111 of the first protruding portion 11 and the area of the first end face 111 of the second protruding portion 11 is S1. The area of the second end face 201 is S3, that is, the area of the end face of the pole piece 200 facing the insulating piece 1 is S3. The ratio of S1 to S3 is the ratio of the area of the second end face 201 of the pole piece 200 to the overall area, and S1 and S3 satisfy 0.2≤S1 / S3≤0.35.

[0044] When the ratio of S1 to S3 is less than 0.2, the contact area between the first end face 111 and the second end face 201 of the pole piece 200 is insufficient, that is, the stress area of the second end face 201 is too small, which can cause the stress of the second end face 201 of the pole piece 200 to be too concentrated, easily causing the second end face 201 to be crushed. In addition, the insufficient contact area between the first end face 111 and the second end face 201 of the pole piece 200 can also cause the fixing effect of the protruding portion 11 on the pole piece 200 to be insufficient, and the pole piece 200 has a risk of displacement in the direction parallel to the first end face 111, which is not conducive to ensuring the quality of the battery cell.

[0045] When the ratio of S1 to S3 is greater than 0.35, the proportion of the area of the second end face 201 of the pole piece 200 under pressure to the overall area of the second end face 201 is too high, the second end face 201 of the pole piece 200 has a tab, and the two sides of the tab will be too close to the protruding portion 11, when there are machining errors and assembly errors, the two sides of the tab are easy to contact the protruding portion 11, and are deformed or even torn under pressure, causing the process yield of the battery cell to be reduced.

[0046] Optionally, in the embodiment, M is 2, and two protrusions 11 are respectively arranged at the two ends of the length direction of the insulating piece 1. Of course, in other embodiments, the number and position of the protrusions 11 can be arranged according to the structural characteristics of the pole group 200, and M can also be 1, 3 or other positive integers.

[0047] Optionally, the edge of the first end surface 111 has a transition curved surface 113 to prevent the edge of the first end surface 111 from being too sharp to damage the second end surface 201. Optionally, each side edge of the first part 1101 is also curvedly transitioned, and each side edge of the second part 1102 is also curvedly transitioned.

[0048] Optionally, in the embodiment, the first part 1101 is a quadrangular columnar structure, that is, the cross section of the first part 1101 is consistent at each position along the height direction of the first part 1101. The second part 1102 is also a quadrangular columnar structure, that is, the cross section of the second part 1102 is consistent at each position along the height direction of the second part 1102.

[0049] Optionally, the cell cover plate 100 further includes a first top cover sheet 2 and a pole column and the like structure.

[0050] In order to verify whether the cell cover plate 100 can solve the problem of the edge and corner of the pole group 200 being crushed, the embodiment also provides cells of different models and sizes, and performs vibration test and CT detection on the cells to analyze the rationality of the above size design.

[0051] As shown in the following Table 1 and Table 2, the embodiment provides twelve groups of examples and four groups of comparative examples of cells. The same points of the twelve groups of examples and the four groups of comparative examples of cells include that one protrusion 11 is arranged at each end of the length direction of the insulating piece 1, the protrusion 11 has a stepped surface 112, and the height h1 of the first part 1101 of the protrusion 11 satisfies 1mm≤h1≤2.5mm.

[0052] As shown in the following Table 1, the cells of the twelve groups of examples all satisfy 0.65≤S1 / S2≤0.9 and 0.2≤S1 / S3≤0.35. The pole groups 200 of the cells of the twelve groups of examples are all successfully put into the shell, five cells of each group of cells are selected for vibration test, and CT detection is performed on the cells after the vibration test is completed. It is found that the tabs of the cells of the twelve groups of examples and the second end surface 201 of the pole group 200 are all normal, and the process yield of the cells is high. On the one hand, the edge and corner of the second end surface 201 of the pole group 200 are not crushed, and on the other hand, the fixing effect of the insulating piece 1 on the pole group 200 is good, and there is no problem of the pole group 200 moving and the tab being torn.

[0053] Table 1

[0054]

[0055]

[0056] As shown in Table 2 below, the ratio of S1 to S3 of the battery cell of Comparative Example 1 does not meet the more optimal value range described above, specifically 0.197, which is less than the minimum value 0.2 of the more optimal value range. That is, the proportion of the contact area between the first end face 111 of the protruding portion 11 and the second end face 201 of the pole group 200 to the overall area of the second end face 201 is low, and the problem of poor fixing effect of the insulating piece 1 on the pole group 200 is prone to occur, the pole group 200 is prone to move, and even the tab is prone to tear. Five battery cells were selected for vibration test, and after the vibration test was completed, the battery cells were subjected to CT detection, and it was found that two of the five battery cells had tab tearing phenomenon, and the process yield of the battery cells was low.

[0057] As shown in Table 2 below, the ratio of S1 to S2 of the battery cell of Comparative Example 2 does not meet the more optimal value range described above, specifically 0.908, which is greater than the maximum value 0.9 of the more optimal value range. That is, the proportion of the first end face 111 of the protruding portion 11 and the sum of the first end face 111 and the stepped face 112 is too high, and when the area of the outer circle of the stepped face 112 is kept unchanged, the stepped face 112 is too narrow, that is, the avoidance groove is too narrow, and when there is a certain machining error and assembly error, the first end face 111 is still prone to crush the edges and corners of the pole group 200. It was found that during the process of the pole group 200 entering the shell, the edges and corners of some pole groups 200 were crushed, and the process yield of the battery cells was low.

[0058] As shown in Table 2 below, the ratio of S1 to S2 of the battery cell of Comparative Example 3 does not meet the more optimal value range described above, specifically 0.905, which is still greater than the maximum value 0.9 of the more optimal value range. That is, the proportion of the first end face 111 of the protruding portion 11 and the sum of the first end face 111 and the stepped face 112 is too high, and when the area of the outer circle of the stepped face 112 is kept unchanged, the stepped face 112 is too narrow, that is, the avoidance groove is too narrow, and when there is a certain machining error and assembly error, the first end face 111 is still prone to crush the edges and corners of the pole group 200. It was found that during the process of the pole group 200 entering the shell, there was still a problem of crushing the edges and corners of some pole groups 200, but the proportion of the battery cells with the problem decreased compared to Comparative Example 2, but overall, the process yield of the battery cells was still low.

[0059] As shown in Table 2 below, the ratio of S1 to S2 of the battery cell of Comparative Example 4 does not meet the more optimal value range described above, specifically 0.955, which is greater than the maximum value 0.9 of the more optimal value range, and the ratio of S1 to S3 also does not meet the more optimal value range described above, specifically 0.354, which is greater than the maximum value 0.35 of the more optimal value range. That is, the ratio of the first end surface 111 of the protruding portion 11 to the sum of the first end surface 111 and the stepped surface 112 is too high, and when the outer circle of the stepped surface 112 is provided with a constant area, the stepped surface 112 is too narrow, that is, the avoidance groove is too narrow, and when there is a certain processing error and assembly error, the first end surface 111 is still prone to crushing the edges and corners of the pole group 200. It is found that the group of battery cells still has the problem of crushing the edges and corners of the pole group 200 during the process of the pole group 200 entering the shell, and the proportion of the battery cells with the problem increases compared to Comparative Example 2, and the process yield of the battery cells is lower.

[0060] Table 2

[0061] S1 (mm2) S2 (mm2) h (mm) S3 (mm2) S1 / S2 S1 / S3 Comparative Example 1 675 1021 1.5 3430 0.661 0.197 Comparative Example 2 2719 2994 2.1 7540 0.908 0.361 Comparative Example 3 4121 4556 1 14040 0.905 0.294 Comparative Example 4 4677 4899 1 13200 0.955 0.354

[0062] The embodiment also provides a battery cell, which includes a pole group 200, a shell, and the battery cell cover plate 100 described above, the battery cell cover plate 100 is sealed and covers the opening of the shell, and the pole group 200 is arranged in the cavity surrounded by the shell.

[0063] Optionally, in the embodiment, the positive electrode and the negative electrode of the battery cell are arranged at opposite ends, and the opposite sides of the battery cell cover plate 100 are provided with a second top cover sheet 400 and an end plate 300, and the end plate 300 contacts the other end of the pole group 200. Of course, in other embodiments, the battery cell cover plate 100 can also be arranged at opposite ends of the battery cell, which is not limited herein.

[0064] The assembly process of the battery cell includes: first, welding the tab at the negative electrode end of the pole group 200 to the negative electrode output end of the battery cell cover plate 100, then wrapping the pole group 200 with an insulating film to form an inner insulating film, and hot melting and fixing one end of the inner insulating film close to the battery cell cover plate 100 to the side wall of the second part 1102 of the insulating part 1 of the battery cell cover plate 100, and hot melting and fixing the other end of the inner insulating film to the end plate 300 at the positive electrode end. Next, the pole group 200 is pushed into the shell to complete the shell entering, then the battery cell cover plate 100 is welded to the shell, the tab at the positive electrode end of the pole group 200 is welded to the positive electrode output end on the second top cover sheet 400, and finally the second top cover sheet 400 is welded to the shell.

[0065] The cell cover plate 100 of the cell can avoid the edges and corners of the second end surface 201 of the pole group 200 by opening the avoiding groove on the protruding part 11 of the insulating part 1, so as to prevent the edges and corners of the pole group 200 from being pressed by the insulating part 1, and improve the process yield and safety performance of the cell. By optimizing the sizes of the protruding part 11 of the insulating part 1, the pole lug can be ensured not to be interfered, and there is no risk of stress deformation and tearing, the stress area of the pole group 200 is large enough, and there is no problem of the pole group 200 being pressed or fixed unstably, so as to ensure the pole group 200 to be smoothly put into the shell, and further improve the process yield and safety performance of the cell.

[0066] Obviously, the above embodiments of the present application are only examples for clearly illustrating the present application, and are not intended to limit the embodiments of the present application. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, all the embodiments are not required to be exhausted. Any modification, equivalent replacement and improvement within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A cell cover, characterized in that: The insulating member (1) comprises M protrusions (11), each of the M protrusions (11) being arranged to protrude toward the pole group (200), a first end face (111) of each protrusion (11) pressing against a second end face (201) of the pole group (200), a side edge of the first end face (111) being recessed to form a step face (112), at least a portion of the step face (112) being arranged corresponding to an edge and a corner of the second end face (201), and M being a positive integer.

2. The cell cover according to claim 1, characterized in that: Each of the protruding portions (11) is divided into a first portion (1101) and a second portion (1102) along the plane where the step surface (112) is located. The first portion (1101) has the first end surface (111). Along a direction perpendicular to the first end surface (111), a height h1 of the first portion (1101) satisfies the following conditions: 1 mm ≤ h1 ≤ 2.5 mm.

3. The cell cover according to claim 1, wherein: Along a direction perpendicular to the first end surface (111), a height H of the protruding portion (11) satisfies: 5 mm ≤ H ≤ 7.5 mm.

4. The cell cover according to claim 1, wherein: Each of the protruding portions (11) is divided into a first portion (1101) and a second portion (1102) along the plane where the step surface (112) is located, the first portion (1101) has the first end surface (111), and along a direction perpendicular to the first end surface (111), the height h2 of the second portion (1102) satisfies: 3mm≤h2≤6mm.

5. The battery cell cover according to any one of claims 1 to 4, characterized in that: The step surface (112) of each protrusion (11) is arranged along the circumference of the first end surface (111).

6. The battery cell cover according to claim 5, characterized in that: The sum of the areas of the M first end surfaces (111) is S1, and the sum of the areas of the surfaces surrounded by the outer edges of the step surfaces (112) of the M protrusions (11) is S2, satisfying: 0.65≤S1 / S2≤0.

9.

7. The battery cell cover according to any one of claims 1 to 4, characterized in that: The sum of the areas of the M first end faces (111) is S1, and the area of ​​the second end face (201) is S3, satisfying: 0.2≤S1 / S3≤0.

35.

8. The battery cell cover according to any one of claims 1 to 4, characterized in that: The value of M is 2, and the two protrusions (11) are respectively arranged at both ends of the insulating member (1) in the length direction.

9. The battery cell cover according to any one of claims 1 to 4, characterized in that: The edge of the first end surface (111) has a transition curved surface (113).

10. A battery cell, characterized in that: The invention comprises a pole group (200), a shell and a cell cover plate according to any one of claims 1 to 9, wherein the cell cover plate (100) is sealed and arranged at the opening of the shell, and the pole group (200) is arranged in a cavity enclosed by the shell.

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