Sealing sheet, battery cell and battery pack

Abstract

The utility model provides a sealing piece, a battery cell and a battery pack, the sealing piece comprises a top surface and a bottom surface which are opposite to each other, the top surface is provided with a first groove, the bottom surface is provided with a second groove, and the first groove and the second groove are at least partially overlapped in the thickness direction of the sealing piece; the sealing piece on the outer side of the groove can deform towards the direction of the groove in the welding process, so that a part of thermal stress is eliminated, and cracks caused by stress concentration are avoided.

Description

TECHNICAL FIELD

[0001] The utility model relates to power battery technical field, concretely relates to a sealing sheet, electric core, battery pack. BACKGROUND

[0002] In the related art, the sealing sheet is a flat nail, the top surface of the sealing sheet is a plane, in the actual welding process, the sealing sheet is prone to cracking under the influence of thermal stress, resulting in problems such as electric core liquid leakage, causing the electric core to be scrapped.

[0003] Therefore, the sealing sheet in the related art has the technical problem of being prone to cracking under the action of thermal stress. SUMMARY

[0004] The embodiments of the utility model provide a sealing sheet, electric core, battery pack, can improve the technical problem that the sealing sheet in prior art is prone to cracking under the action of thermal stress.

[0005] In a first aspect, the embodiments of the utility model provide a sealing sheet, including opposite top surface and bottom surface, the top surface is equipped with first recess, the bottom surface is equipped with second recess, the first recess and the second recess at least partially overlap in the thickness direction of the sealing sheet.

[0006] In an embodiment, the diameter of the top surface is greater than the diameter of the bottom surface, and the diameter of the first recess is greater than the diameter of the second recess.

[0007] In an embodiment, the second recess is located within the boundary of the first recess in the orthographic projection on the top surface.

[0008] In an embodiment, the center line of the second recess coincides with the center line of the first recess.

[0009] In an embodiment, the welding portion of the outer side of any of the sealing sheets is used for welding to the top cover, wherein the diameter of the first recess is D1, the diameter of the top surface is D, the width of the welding portion is t / 2, and 0

[0010] In an embodiment, the included angle between the side wall of the first recess and the bottom surface of the first recess is an obtuse angle, and the included angle between the side wall of the second recess and the top wall of the second recess is an obtuse angle.

[0011] In an embodiment, it further includes a connecting portion located between the first recess and the second recess, and a main body portion arranged around the first recess and the second recess, the connecting portion is connected to the inner side of the main body portion, wherein the thickness of the connecting portion is greater than or equal to one third of the thickness of the main body portion, and less than the thickness of the main body portion.

[0012] In an embodiment, an inner surface of the first groove and / or the second groove is provided with at least one sub-groove.

[0013] In a second aspect, the embodiments of the utility model provide a battery cell, which comprises the sealing sheet according to any one of the above embodiments.

[0014] In a third aspect, the embodiments of the utility model provide a battery pack, which comprises the sealing sheet or the battery cell according to any one of the above embodiments.

[0015] The embodiments of the utility model have the beneficial effects that:

[0016] In the embodiments of the utility model, the first groove and the second groove are at least partially overlapped by being respectively arranged on the top surface and the bottom surface of the sealing sheet, and the sealing sheet can be deformed towards the direction of the groove during the welding process, so that a part of thermal stress is eliminated, and cracks caused by stress concentration are avoided. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the utility model, the drawings needed to be used in the embodiment description will be briefly introduced, and obviously, the drawings in the following description are only some embodiments of the utility model, and other drawings can be obtained according to these drawings without creative labor for those skilled in the art.

[0018] Figure 1 is a sectional view of the sealing sheet provided by the embodiments of the utility model;

[0019] Figure 2 is a three-dimensional schematic view of the sealing sheet under the first visual angle provided by the embodiments of the utility model;

[0020] Figure 3 is a three-dimensional schematic view of the sealing sheet under the second visual angle provided by the embodiments of the utility model. DETAILED DESCRIPTION

[0021] Clearly and completely describe the technical scheme in the embodiments of the utility model with reference to the drawings in the embodiments of the utility model, obviously, the described embodiments are only a part of the embodiments of the utility model, and not all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by the person skilled in the art without making creative efforts belong to the scope of protection of the utility model. In addition, it should be understood that the specific implementation described herein is only used to illustrate and explain the utility model, and is not used to limit the utility model. In the utility model, the orientation words such as ''up'' and ''down'' are generally used to indicate the up and down of the device in the actual use or working state, and the specific is the drawing direction in the drawing. And ''inside'' and ''outside'' are relative to the outline of the device.

[0022] In addition, the terms ''first'', ''second'' and similar words do not represent any order, quantity or importance, but are only used to distinguish different technical features. The term ''a plurality of'' and similar words represent two or more, unless otherwise explicitly limited.

[0023] Please refer to Figures 1 to 3 The sealing sheet 1 provided by the embodiments of the utility model includes opposite top surface and bottom surface, the top surface is provided with the first groove 2, the bottom surface is provided with the second groove 3, and the first groove 2 and the second groove 3 at least partially overlap in the thickness direction of the sealing sheet 1.

[0024] In the embodiment, since the top surface and the bottom surface of the sealing sheet 1 are respectively provided with grooves, and the first groove 2 and the second groove 3 at least partially overlap in the thickness direction, the sealing sheet 1 around the grooves can be deformed in the direction of the grooves during the welding process, thereby eliminating part of the thermal stress and avoiding cracks caused by stress concentration.

[0025] The technical scheme of the present application will be described in conjunction with specific embodiments.

[0026] In one embodiment, the diameter of the top surface is greater than the diameter of the bottom surface, and the diameter of the first groove 2 is greater than the diameter of the second groove 3.

[0027] The bottom surface is located in the liquid injection hole of the battery cell, and the top surface can be flush with the top surface of the liquid injection hole.

[0028] It can be understood that when the sealing sheet 1 is inverted trapezoidal, that is, the diameter of the bottom surface is smaller than the diameter of the top surface, the sealing sheet 1 is inserted into the liquid injection hole, and at the same time, the first groove 2 with a larger diameter is formed on the top surface with a larger diameter, and the second groove 3 with a smaller diameter is formed on the bottom surface with a smaller diameter, so that the size of the sealing sheet 1 around the first groove 2 and the second groove 3 is similar, the deformation amount of the sealing sheet 1 around the first groove 2 and the second groove 3 is similar, and the elimination of thermal stress is more uniform.

[0029] In an embodiment, referring to Figure 1 , the orthographic projection of the second groove 3 on the top surface is located within the boundary of the first groove 2.

[0030] In an embodiment, referring to Figure 2 , Figure 3 , the first groove 2 and the second groove 3 are both circular grooves, and the center line of the second groove 3 coincides with the center line of the first groove 2.

[0031] It can be understood that the cross-sectional shape of the first groove 2 and the second groove 3 can be circular, so that the center lines of the first groove 2 and the second groove 3 can be collinear, thereby forming the first groove 2 and the second groove 3 around the same center line.

[0032] In an embodiment, the size of the first groove 2 can be the same as the size of the second groove 3.

[0033] In the present embodiment, the same process can be used to manufacture the first groove 2 and the second groove 3, thereby reducing the process steps and thus reducing the cost.

[0034] In an embodiment, referring to Figure 1 , the diameter of the first groove 2 needs to be at least greater than or equal to one-third of the diameter of the top surface of the sealing sheet 1.

[0035] In an embodiment, the diameter of the first groove 2 can be one-third, one-half, two-thirds, or four-fifths of the diameter of the top surface of the sealing sheet 1.

[0036] In an embodiment, referring to , the diameter of the second groove 3 needs to be at least greater than or equal to one-third of the diameter of the bottom surface of the sealing sheet 1.

[0037] Figure 1 In an embodiment, referring to , any welding portion 6 on the outer side of the sealing sheet 1 is used for welding to the top cover; wherein the diameter of the first groove 2 is D1, the diameter of the top surface of the sealing sheet 1 is D, the width of the welding portion 6 is t / 2, and 0

[0038] In an embodiment, referring to

[0039] , the top cover is located at the top of the battery cell, and the top cover is provided with a liquid injection hole.

[0040] In an embodiment, referring to , in any longitudinal section, the welding portion 6 includes a first sub-portion 61 located on one side of the sealing sheet 1 and a second sub-portion 62 located on the other side of the sealing sheet 1.

[0041] In an embodiment, referring to

[0042] The welding portion 6 is arranged around the first groove 2.

[0043] The diameter of the second groove 3 is d1, the diameter of the bottom surface of the sealing sheet 1 is d, and 0≤d1≤d.

[0044] It can be understood that the first groove 2 needs to be arranged staggered with the welding portion 6, and the diameter range of the first groove 2 needs to be less than or equal to the diameter of the top surface of the sealing sheet 1 minus the width of the welding portion 6, so as to avoid that the first groove 2 is formed on the welding portion 6, resulting in welding failure of the welding portion 6.

[0045] It can be understood that the welding portion 6 refers to the part on the sealing sheet 1 for welding. In the welding process, the welding portion 6 is melted and welded with the top surface of the top cover. At any welding point of the sealing sheet 1, the width of the welding portion 6 can be t / 2, and the width of the top surface of the liquid injection hole for welding can be t / 2.

[0046] In the embodiment, by making the diameter of the first groove 2 satisfy 0

[0047] In an embodiment, the width of the welding portion is the same everywhere.

[0048] In an embodiment, referring to Figure 1 , the included angle between the side wall of the first groove 2 and the bottom surface of the first groove 2 is obtuse, and / or the included angle between the side wall of the second groove 3 and the top wall of the second groove 3 is obtuse.

[0049] The obtuse angle can be any one of 100 degrees, 120 degrees, 135 degrees, 150 degrees, and 170 degrees.

[0050] It can be understood that by making the included angle between the side wall of the first groove 2 and the bottom surface of the first groove 2 be obtuse, the total area of the side wall of the first groove 2 can be increased. Similarly, by making the included angle between the side wall of the second groove 3 and the bottom surface of the second groove 3 be obtuse, the total area of the side wall of the second groove 3 can be increased. By increasing the total areas of the first groove 2 and the second groove 3, the heat dissipation area of the sealing sheet 1 is increased.

[0051] It should be noted that the heat dissipation efficiency of the sealing sheet 1 is positively correlated with the heat dissipation area. By opening the first groove 2 and the second groove 3, the heat dissipation area can be increased. Further, by making the included angle between the side wall and the bottom surface of the first groove 2 and / or the included angle between the side wall and the bottom surface of the second groove 3 be obtuse, the heat dissipation area is further increased.

[0052] It should be noted that when the height of the first groove 2 is constant, the greater the obtuse angle between the side wall of the first groove 2 and the bottom surface of the first groove 2, the greater the heat dissipation area of the sealing sheet 1, and when the height of the second groove 3 is constant, the greater the obtuse angle between the side wall of the second groove 3 and the bottom surface of the second groove 3, the greater the heat dissipation area of the sealing sheet 1.

[0053] In the present embodiment, by making the included angle between the side wall and the bottom surface of the first groove 2 and / or the second groove 3 an obtuse angle, the heat dissipation area can be increased, the heat dissipation effect can be improved, the heat diffusion during welding can be facilitated, and the generation of thermal stress can be effectively alleviated.

[0054] In an embodiment, the included angle between the side wall of the first groove 2 and the bottom surface of the first groove 2 can also be 90 degrees.

[0055] In an embodiment, the included angle between the side wall of the second groove 3 and the bottom surface of the second groove 3 can also be 90 degrees.

[0056] In an embodiment, the included angle between the side wall of the first groove 2 and the first groove 2 can be a rounded angle.

[0057] In an embodiment, the included angle between the side wall of the second groove 3 and the second groove 3 can be a rounded angle.

[0058] In an embodiment, the included angle between the side wall of the first groove 2 and the top surface of the sealing sheet 1 can be a rounded angle.

[0059] In an embodiment, the included angle between the side wall of the second groove 3 and the bottom surface of the sealing sheet 1 can be a rounded angle.

[0060] In the present embodiment, by making each of the top angles of the first groove 2 and the second groove 3 a rounded angle, on the one hand, the heat dissipation area of the rounded angle will be larger, and on the other hand, the structure transition of the rounded angle is gentle, which is conducive to the release of thermal stress and avoids the concentration of thermal stress.

[0061] In an embodiment, it further includes a connecting portion 4 located between the first groove 2 and the second groove 3, and a main body portion 5 arranged around the first groove 2 and the second groove 3, the connecting portion 4 is connected to the inner side of the main body portion 5, wherein the thickness of the connecting portion 4 is greater than or equal to one third of the thickness of the main body portion 5 and less than the thickness of the main body portion 5.

[0062] In an embodiment, the depth of the first groove 2 can be the same as the depth of the second groove 3.

[0063] The main body 5 can include a first sub-portion located outside the first groove 2, a second sub-portion located outside the second groove 3, and a third sub-portion connected between the first sub-portion and the second sub-portion. The thickness of the first sub-portion is the same as the depth of the first groove 2, the thickness of the second sub-portion is the same as the depth of the second groove 3, and the thickness of the third sub-portion is the same as the thickness of the connecting portion 4.

[0064] The depth of the first groove 2, the depth of the second groove 3, and the thickness of the connecting portion 4 can each be one-third of the thickness of the main body 5.

[0065] It can be understood that when the thickness of the connecting portion 4 is less than one-third of the thickness of the main body 5, the structural strength of the connecting portion 4 is insufficient, which can easily cause the sealing sheet 1 to break and thus fail.

[0066] It should be noted that the first groove 2 and the second groove 3 need to have a certain depth. Specifically, in this embodiment, the depth of the first groove 2 and the second groove 3 is ensured to be a certain depth, and the thickness of the connecting portion 4 is greater than one-third of the thickness of the main body 5, which can improve the structural strength of the connecting portion 4 and avoid the sealing sheet 1 from failing due to the easy breaking of the connecting portion 4.

[0067] In an embodiment, the inner surface of the first groove 2 and / or the second groove 3 is provided with at least one sub-groove.

[0068] The sub-groove can be provided on the bottom surface of the first groove 2, and the sub-groove can also be provided on the side wall of the first groove 2.

[0069] The sub-groove can also be provided on the bottom surface of the second groove 3, and the sub-groove can also be provided on the side wall of the second groove 3.

[0070] The plurality of sub-grooves can have the same size, which includes at least one of length, width, height, and shape.

[0071] It can be understood that the inner surface of the first groove 2 and / or the second groove 3 can be roughened to have at least one sub-groove, which can further increase the heat dissipation area of the sealing sheet 1 to improve the heat dissipation efficiency.

[0072] In this embodiment, the heat dissipation area of the sealing sheet 1 is improved by providing at least one sub-groove on the inner surface of the first groove 2 and / or the second groove 3, which effectively avoids the concentration of thermal stress.

[0073] In an embodiment, the side wall of the first groove 2 and / or the side wall of the second groove 3 is in a stepped shape.

[0074] The side wall of the first groove 2 comprises at least two steps arranged along the depth direction of the first groove 2, and the size between any two steps can be the same.

[0075] The side wall of the second groove 3 comprises at least two steps arranged along the depth direction of the first groove 2, and the size between any two steps can be the same.

[0076] The side wall of the step can be an inclined surface arranged obliquely relative to the bottom surface of the step, that is, the included angle between the side wall of the step and the vertical direction is an acute angle.

[0077] It can be understood that the at least two steps comprise two steps, three steps, four steps,..., N steps, N being a positive integer greater than 4.

[0078] It can be understood that arranging the side wall of the first groove 2 and / or the side wall of the second groove 3 in a stepped manner can further increase the heat dissipation area of the sealing sheet 1.

[0079] In the embodiment, by arranging the side wall of the first groove 2 and / or the side wall of the second groove 3 in a stepped manner, the heat dissipation area of the side wall of the first groove 2 and / or the second groove 3 is increased, the heat dissipation efficiency is improved, and the cracking of the sealing sheet 1 caused by the influence of thermal stress is avoided.

[0080] In one embodiment, the main body part 5 comprises a first part surrounding the first groove 2, a second part surrounding the second groove 3, and a third part connected between the first part and the second part, wherein the thickness of the first part is equal to the thickness of the second part along the opening of the first groove 2.

[0081] The preparation materials of the connecting part 4 and the main body part 5 are the same.

[0082] The preparation materials of the connecting part 4 and the main body part 5 can comprise aluminum.

[0083] It can be understood that by equalizing the depth of the first groove 2 and the depth of the second groove 3, the thickness of the first sub-part can be equal to the thickness of the second sub-part. The deformation amount of the first sub-part and the second sub-part under the action of thermal stress is related to the thickness and width of the first sub-part and the second sub-part. In any longitudinal section, the width and thickness of the first sub-part and the second sub-part can be equal, so that the elastic deformation of the first sub-part and the second sub-part is more uniform.

[0084] It should be noted that the deformation of the main body part 5 towards the first groove 2 and the second groove 3 is elastic deformation, and the elastic deformation is linear.

[0085] In the embodiment, the first sub-part and the second sub-part of the main body 5 are located outside the first groove 2 and the second groove 3, respectively, and have the same deformation amount under the action of thermal stress, so that the release of thermal stress is more uniform, and the uniformity of the heat dissipation efficiency is improved.

[0086] In an embodiment, the heat dissipation area of the sealing sheet 1 is S, which satisfies S=π(D1+D2)L1+π(d1+d2)L2+π(D22+d22).

[0087] L1=(D1-D2) / 2cos(180°-α), L2=(d1-d2) / 2cos(180°-β).

[0088] In the cross section as shown in FIG. 1, D1 is the diameter of the top surface of the first groove 2, D2 is the diameter of the bottom surface of the first groove 2, D is the diameter of the top surface of the sealing sheet 1, L1 is the length of the side wall of the first groove 2, and α is the included angle between the side wall of the first groove 2 and the bottom surface of the first groove 2. Figure 1 In the cross section as shown in FIG. 1, d1 is the diameter of the top surface of the second groove 3, d2 is the diameter of the bottom surface of the first groove 2, d is the diameter of the top surface of the sealing sheet 1, L2 is the length of the side wall of the second groove 3, and β is the included angle between the side wall of the second groove 3 and the bottom surface of the second groove 3.

[0089] Figure 1 It can be understood that, through the calculation formula of the heat dissipation area S, it can be seen that, by setting the first groove 2 and the second groove 3, compared with not setting the groove or setting only one groove on the bottom surface / top surface, the heat dissipation area can be further improved to improve the heat dissipation efficiency and avoid the adverse effects caused by the concentration of thermal stress.

[0090] In an embodiment, the sealing sheet 1 is an aluminum sheet or a copper sheet.

[0091] In an embodiment, the sealing sheet 1 is an aluminum sheet or a copper sheet.

[0092] In an embodiment, the sealing sheet 1 is an aluminum sheet or a copper sheet.

[0093] In an embodiment, the sealing sheet 1 is an aluminum sheet or a copper sheet.

[0094] In an embodiment, the sealing sheet 1 is an aluminum sheet or a copper sheet.

[0095] In an embodiment, the sealing sheet 1 is an aluminum sheet or a copper sheet.

[0096] In an embodiment, the sealing sheet 1 is an aluminum sheet or a copper sheet.

[0097] ​The application discloses a sealing sheet 1 in an H-shaped structure, a first groove 2 and a second groove 3 are respectively arranged on a top surface and a bottom surface of the sealing sheet 1, and the first groove 2 and the second groove 3 at least partially overlap, so that a main body 5 located outside the first groove 2 and the second groove 3 can be deformed towards the first groove 2 and the second groove 3 when heated, thereby relieving thermal stress and avoiding the rupture of the sealing sheet 1 caused by stress concentration.

[0098] The sealing sheet 1 comprises opposite top and bottom surfaces, the top surface is provided with the first groove 2, the bottom surface is provided with the second groove 3, the first groove 2 and the second groove 3 at least partially overlap in the thickness direction of the sealing sheet 1, and the sealing sheet 1 around the grooves can be deformed towards the grooves during welding, so as to eliminate part of thermal stress and avoid cracks caused by stress concentration.

[0099] The above detailed introduction is made to the embodiments of the application, and the principles and implementation manners of the application are described by applying specific examples; the above embodiment description is only used for helping to understand the method and the core idea of the application; meanwhile, the specific implementation manners and application ranges can be changed according to the principles of the application by the person skilled in the art, and the above description should not be understood as the limitation of the application.

Claims

1. A sealing sheet, characterized by, The sealing sheet comprises opposite top and bottom surfaces, the top surface is provided with a first groove, the bottom surface is provided with a second groove, and the first groove and the second groove at least partially overlap in the thickness direction of the sealing sheet. The sealing sheet further comprises a connecting portion between the first groove and the second groove, and a main body portion surrounding the first groove and the second groove, the connecting portion is connected to the inner side of the main body portion, wherein the thickness of the connecting portion is greater than or equal to one third of the thickness of the main body portion, and less than the thickness of the main body portion.

2. The sealing sheet according to claim 1, wherein The diameter of the top surface is greater than the diameter of the bottom surface, and the diameter of the first groove is greater than the diameter of the second groove.

3. The sealing sheet according to claim 2, wherein The orthographic projection of the second groove on the top surface is located within the boundary of the first groove.

4. The sealing sheet according to claim 3, characterized by The center line of the second groove coincides with the center line of the first groove.

5. The sealing sheet according to any one of claims 1 to 4, characterized in that, The welding portion on the outer side of the sealing sheet is used for welding to a top cover; wherein the diameter of the first groove is D1, the diameter of the top surface is D, the width of the welding portion is t / 2, and 0 6. The sealing sheet according to any one of claims 1 to 4, wherein The included angle between the side wall of the first groove and the bottom surface of the first groove is obtuse, and the included angle between the side wall of the second groove and the top wall of the second groove is obtuse.

7. The sealing sheet according to any one of claims 1 to 4, wherein The inner surface of the first groove and / or the second groove is provided with at least one sub-groove.

8. An electric cell characterized by The sealing sheet comprises the sealing sheet according to any one of claims 1 to 7.

9. A battery pack, characterized by, The battery cell comprises the sealing sheet according to any one of claims 1 to 7, or the battery cell according to claim 8.

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