Cover plate assembly, single battery and battery pack

Abstract

The utility model discloses a cover plate assembly, a single battery and a battery pack, and belongs to the technical field of batteries, the cover plate assembly comprises a cover plate, and the cover plate is provided with a pressure relief hole; the insulating part is connected with the cover plate, the insulating part faces the pressure relief hole, and the insulating part is provided with a placement cavity; the supporting piece is arranged in the placement cavity, and the melting point of the supporting piece is larger than that of the insulating piece; and the covering and sealing piece covers and seals the placement cavity. When thermal runaway of the battery occurs, the supporting piece can be effectively kept between the cover plate and the electrode assembly, the electrode assembly is prevented from moving towards the cover plate and blocking the pressure relief hole, high-temperature gas generated by thermal runaway of the battery can be smoothly discharged from the pressure relief hole, and the safety of the battery is improved.

Description

Technical Field

[0001] The present application belongs to the field of battery technology, and specifically relates to a cover plate assembly, a single cell and a battery pack. Background Art

[0002] At present, in order to improve the safety of battery use, it is usually necessary to set an explosion-proof structure on the battery cover. When the battery has thermal runaway, the explosion-proof structure can be broken in time and the pressure and exhaust can be released smoothly. The battery shell also needs to be provided with various insulating fixing structures between the electrode assembly and the cover to stabilize and fix the electrode assembly. When the battery has thermal runaway, the various insulating fixing structures in the shell are easily melted and disappeared by heat. At this time, the electrode assembly is easy to move to the cover under the action of high temperature and high pressure gas and block the explosion-proof structure, which will cause the battery to catch fire or even explode. Utility Model Content

[0003] Purpose of the utility model: An embodiment of the present application provides a cover plate assembly, aiming to solve the above-mentioned technical problems; another purpose of an embodiment of the present application is to provide a single cell battery; another purpose of an embodiment of the present application is to provide a battery pack.

[0004] Technical solution: A cover plate assembly described in an embodiment of the present application includes:

[0005] A cover plate, wherein the cover plate is provided with a pressure relief hole;

[0006] An insulating member, the insulating member is connected to the cover plate, the insulating member faces the pressure relief hole, and the insulating member has a placement cavity;

[0007] A support member, the support member is disposed in the placement cavity, and the melting point of the support member is greater than the melting point of the insulating member;

[0008] A cover seal is used to seal the housing cavity.

[0009] In some embodiments, the insulating member and the cover seal are integrally formed, and the insulating member and the cover seal surround the housing cavity.

[0010] In some embodiments, an orthographic projection of the support member on the cover plate is at least partially located outside the pressure relief hole.

[0011] In some embodiments, the insulating member is provided with an exhaust hole, the exhaust hole is connected to the pressure relief hole, and an orthographic projection of the exhaust hole on the cover plate is at least partially located in the pressure relief hole.

[0012] In some embodiments, the insulating member is provided with a through hole for allowing the electrode tab of the electrode assembly to pass through, and the through hole is located on a side of the supporting member away from the exhaust hole.

[0013] In some embodiments, the wall thickness of the insulating member wrapped around the outer side of the support member is a mm, satisfying: 0.7 mm ≥ a mm ≥ 0.5 mm;

[0014] And / or, the wall thickness of the cover sealing member in a direction perpendicular to the support member is b mm, satisfying: 0.7 mm ≥ b mm ≥ 0.5 mm.

[0015] In some embodiments, the Rockwell hardness of the insulating member is c, satisfying: 90≥c≥60.

[0016] In some embodiments, the melting point of the support member is d°C, satisfying: d°C ≥ 600°C.

[0017] Correspondingly, a single cell battery described in an embodiment of the present application includes: a cover plate assembly as described above, and also includes a shell and an electrode assembly, the shell having a accommodating cavity and an opening connected to the accommodating cavity, the electrode assembly and the insulating member are arranged in the accommodating cavity, the cover plate is covered on the opening, and the insulating member is located between the cover plate and the electrode assembly.

[0018] Correspondingly, a battery pack described in an embodiment of the present application includes: a single cell as described above.

[0019] Beneficial effect: The cover plate assembly of the embodiment of the present application includes a cover plate, an insulating member, a support member and a cover sealing member, wherein the cover plate is provided with a pressure relief hole, the insulating member is connected to the cover plate, the insulating member faces the pressure relief hole, the insulating member has an installation cavity, the support member is arranged in the installation cavity, and the cover sealing member seals the installation cavity, the melting point of the support member is greater than the melting point of the insulating member; the installation cavity forms a positioning for the support member, improves the installation stability of the support member and at the same time reduces the increase in the overall thickness of the cover plate assembly caused by the support member, when thermal runaway occurs in the battery, the insulating member melts under high temperature and gradually loses its supporting effect on the electrode assembly inside the battery, the support member is more resistant to high temperature than the insulating member, and can effectively maintain the support between the cover plate and the electrode assembly, avoiding the electrode assembly from moving toward the cover plate and blocking the pressure relief hole, which is beneficial to the high-temperature gas generated by thermal runaway of the battery to be discharged smoothly from the pressure relief hole, thereby improving the safety of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 It is a schematic diagram of the exploded structure of the cover plate assembly, the shell, and the electrode assembly provided in the embodiment of the present application;

[0022] Figure 2 is a schematic structural diagram of an insulating member provided in an embodiment of the present application;

[0023] Figure 3 is a schematic structural diagram of an insulating member provided in an embodiment of the present application, viewed from the front of a structural groove opening;

[0024] Figure 4 yes Figure 3 Schematic diagram of the cross-sectional structure along line AA;

[0025] Figure numerals: 1, cover plate assembly; 10, cover plate; 100, pressure relief hole; 101, pressure relief valve; 102, pole; 11, insulating member; 110, placement cavity; 111, structural groove; 112, exhaust hole; 113, through hole; 12, support member; 13, cover sealing member; 2, shell; 20, accommodating cavity; 21, opening; 22, side plate; 3, electrode assembly; 30, pole ear; 4, bottom cover member; X, first direction; Y, second direction; Z, third direction. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0027] In the description of the present application, it should be understood that the terms "thickness", "upper", "lower", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more features. In the description of the present application, "multiple" means two or more, and at least one means one, two or more, unless otherwise clearly and specifically defined.

[0028] The applicant noted that in addition to the electrode assembly, various insulating fixing structures are required in the battery shell to stably fix the electrode assembly. Most of the insulating fixing structures are made of plastic materials such as polypropylene, which have a melting point of about 160°C. When the battery has thermal runaway, the internal temperature of the battery can reach above 400°C. The various insulating fixing structures in the shell are easily melted and disappear due to heat. At this time, the electrode assembly is easily moved to the battery pressure relief structure under the action of high-temperature and high-pressure gas and block the pressure relief structure, thereby causing the battery to catch fire or even explode.

[0029] In view of this, combined with Figures 1 to 4 , an embodiment of the present application provides a cover plate assembly, aiming to overcome at least one of the above-mentioned technical problems.

[0030] In the following embodiments, a first direction X, a second direction Y and a third direction Z that intersect each other are introduced, wherein the first direction X is parallel to the thickness direction of the cover assembly 1, the second direction Y is parallel to the length direction of the cover assembly 1, and the third direction Z is parallel to the width direction of the cover assembly 1.

[0031] Reference Figures 1 to 4 The cover plate assembly 1 includes a cover plate 10, an insulating member 11, a support member 12 and a cover sealing member 13, wherein the cover plate 10 is provided with a pressure relief hole 100, the insulating member 11 is connected to the cover plate 10 and faces the pressure relief hole 100, the insulating member 11 has an accommodation cavity 110, the support member 12 is arranged in the accommodation cavity 110, and the melting point of the support member 12 is greater than the melting point of the insulating member 11, and the cover sealing member 13 seals the accommodation cavity 110.

[0032] The placement cavity 110 forms a positioning for the support member 12, improves the placement stability of the support member 12 and at the same time reduces the increase in the overall thickness of the cover plate assembly 1 caused by the support member 12. When the battery has thermal runaway, the insulating member 11 melts at high temperature and gradually loses its supporting effect on the electrode assembly 3 inside the battery. The support member 12 is more resistant to high temperatures than the insulating member 11, and can effectively maintain support between the cover plate 10 and the electrode assembly 3, preventing the electrode assembly 3 from moving toward the cover plate 10 and blocking the pressure relief hole 100, which is conducive to the smooth discharge of high-temperature gas generated by thermal runaway of the battery from the pressure relief hole 100, thereby improving the safety of the battery.

[0033] It should be noted that the insulating member 11 can be made of plastic material such as polymers such as polypropylene. The insulating member 11 begins to melt at about 160°C. In this embodiment, the support member 12 is designed to be a block structure. The support member 12 can be embedded in the placement cavity 110. The support member 12 can be made of a material with a melting point higher than 600°C, such as ceramic material, bakelite, resin, etc. Taking the support member 12 made of ceramic material as an example, its melting point can be greater than 2000°C, which can better maintain support between the electrode assembly 3 and the cover plate 10 under high temperature of thermal runaway of the battery.

[0034] Specifically, in some embodiments, referring to Figures 1 to 4 The insulating member 11 and the cover seal 13 are integrally formed, and the insulating member 11 and the cover seal 13 surround a placement cavity 110. In this embodiment, the insulating member 11 and the cover seal 13 can be integrally injection molded, and the support member 12 can be pre-placed in the injection mold cavity. During the molding process of the insulating member 11 and the cover seal 13, the support member 12 is covered and the placement cavity 110 is formed. The process is simple, and the high temperature resistance of the overall cover plate assembly 1 is improved without changing the overall product appearance size.

[0035] It should be noted that in order to ensure the effect of the insulating member 11 and the cover sealing member 13 on the plastic injection molding of the support member 12, ensure that the plastic injection molding of the support member 12 is sufficient, and reduce the occurrence of cracks and other problems during the use of the cover assembly 1, in some embodiments, refer to Figures 1 to 4 The wall thickness of the insulating member 11 wrapped around the outer side of the supporting member 12 is a mm, satisfying: 0.7 mm ≥ a mm ≥ 0.5 mm, and a can be any one of 0.5 mm, 0.51 mm, 0.52 mm, 0.53 mm, 0.54 mm, 0.55 mm, 0.56 mm, 0.57 mm, 0.58 mm, 0.59 mm, 0.6 mm, 0.61 mm, 0.62 mm, 0.63 mm, 0.64 mm, 0.65 mm, 0.66 mm, 0.67 mm, 0.68 mm, 0.69 mm, and 0.7 mm, or a range value consisting of any two of them.

[0036] At the same time, the wall thickness of the cover seal 13 in the direction perpendicular to the support member 12 is b mm, which satisfies: 0.7 mm ≥ b mm ≥ 0.5 mm, and b can be any one of 0.5 mm, 0.51 mm, 0.52 mm, 0.53 mm, 0.54 mm, 0.55 mm, 0.56 mm, 0.57 mm, 0.58 mm, 0.59 mm, 0.6 mm, 0.61 mm, 0.62 mm, 0.63 mm, 0.64 mm, 0.65 mm, 0.66 mm, 0.67 mm, 0.68 mm, 0.69 mm, and 0.7 mm, or any two of them. When the values ​​of a and b are greater than 0.7 mm, the wall thickness of the cover seal 13 and the insulating member 11 is too large, which affects the size of the overall cover plate assembly 1 and increases the overall mass. When the values ​​of a and b are less than 0.5 mm, the overall coating strength formed by the cover seal 13 and the insulating member 11 is low.

[0037] In addition, in order to ensure that the insulating part 11 has sufficient elastic deformation ability to adapt to the thermal expansion and contraction of its own material and the support part 12, and to reduce the problem that the placement cavity 110 is unable to shrink during the cooling process of injection molding and cannot meet the shrinking variable of the support part 12, causing the support part 12 to squeeze the insulating part 11 and the covering part 13 and cause cracking, the Rockwell hardness of the insulating part 11 in this embodiment is c, satisfying: 90≥c≥60, c can be any one of 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90 or a range value composed of any two of them.

[0038] In some embodiments, reference Figures 1 to 4 During the molding process, the insulating member 11 may also form a plurality of structural grooves 111. The structural grooves 111 may reduce the material usage of the entire insulating member 11 and reduce the overall quality of the insulating member 11. The number of structural grooves 111 may be flexibly adjusted according to the size and structural requirements of the actual insulating member 11. In this embodiment, two structural grooves 111 are formed as an example. The two structural grooves 111 and the placement cavity 110 are sequentially arranged at intervals in the second direction Y. The structural grooves 111 face the pressure relief hole 100 in the first direction X. The insulating member 11 is provided with an exhaust hole 112 in the first direction X. The exhaust hole 112 is located in the structural groove 111 and is connected to the pressure relief hole 100.

[0039] Specifically, refer to Figures 1 to 4 In this embodiment, each structural groove 111 is provided with a plurality of exhaust holes 112, and the plurality of exhaust holes 112 are evenly distributed in the structural groove 111, and the orthographic projection of the exhaust hole 112 on the cover plate 10 is at least partially located in the pressure relief hole 100. When the battery has thermal runaway, the high-temperature and high-pressure gas generated inside the battery can be discharged from the exhaust hole 112 toward the pressure relief hole 100, and the opening area of ​​the plurality of exhaust holes 112 needs to ensure that the exhaust holes 112 can provide sufficient exhaust efficiency under the premise of ensuring that the insulating member 11 and the electrode assembly 3 have sufficient contact area.

[0040] In some embodiments, reference Figures 1 to 4 , the orthographic projection of the support member 12 on the cover plate 10 is at least partially located outside the pressure relief hole 100. In this embodiment, taking the formation position of the placement cavity 110 and the position of the pressure relief hole 100 as an example, the corresponding support member 12 is not opposite to the pressure relief hole 100 in the first direction X, so as to avoid the support member 12 from forming an obstruction to the exhaust passage of the pressure relief hole 100, and at the same time avoid the installation structure of the support member 12 from affecting the installation of structures such as the pressure relief valve 101 at the pressure relief hole 100.

[0041] In addition, in other embodiments, when the opening area of ​​the pressure relief hole 100 is designed to be larger, the placement cavity 110 may also be partially opposite to the pressure relief hole 100. At this time, although part of the support member 12 is opposite to the pressure relief hole 100 in the first direction X, it can still ensure that the pressure relief hole 100 can release pressure smoothly.

[0042] In addition, in some embodiments, reference Figures 1 to 4 The insulating member 11 is provided with a through hole 113 in the first direction X for the tab 30 to pass through. In the actual assembly process, the through hole 113 is used for the tab 30 of the electrode assembly 3 to pass through so as to be electrically connected to the pole 102 on the cover plate 10. In this embodiment, the through hole 113 is located on the side of the placement cavity 110 away from the structural groove 111 in the second direction Y.

[0043] Correspondingly, this embodiment also provides a single cell.

[0044] Reference Figure 1 The single cell includes the above-mentioned cover plate assembly 1, and also includes a shell 2 and an electrode assembly 3. The shell 2 has a accommodating cavity 20, and the shell 2 is provided with an opening 21 connected to the accommodating cavity 20 at one end in the first direction X. The electrode assembly 3 has a pole ear 30 at one end in the first direction X. The electrode assembly 3 and the insulating member 11 are arranged in the accommodating cavity 20, and the pole ear 30 faces the cover plate 10. The cover plate 10 is provided with a pole column 102 opposite to the pole ear 30. When the cover plate 10 is covered on the opening 21, the pole ear 30 can pass through the through hole 113 and be electrically connected to the pole column 102, and the insulating member 11 is located between the cover plate 10 and the electrode assembly 3, and the support member 12 is arranged between the cover plate 10 and the electrode assembly 3 to form a preset support structure.

[0045] In addition, if Figure 1 As shown, a side plate 22 is further provided in the shell 2 on one side of the electrode assembly 3 in the second direction Y. The side plate 22 and the insulating member 11 are both fixedly connected to the shell 2 as fixing structures of the electrode assembly 3 .

[0046] In addition, in this embodiment, referring to Figure 1 The shell 2 is further provided with a bottom cover 4 at the other end in the first direction X. The structure of the bottom cover 4 is similar to that of the cover plate 10. In this embodiment, it is only used to seal the shell 2 and lead out the electrode. In other embodiments, if the bottom cover 4 is also provided with a pressure relief structure, a support member 12 can also be added between the bottom cover 4 and the electrode assembly 3, so as to ensure that the pressure relief structure at the bottom cover 4 is not blocked by the electrode assembly 3 when thermal runaway occurs in the battery.

[0047] Accordingly, the embodiment of the present application further provides a battery pack, which includes the above-mentioned single battery. It is understandable that the battery pack can have all the technical features and corresponding beneficial effects of the above-mentioned single battery, which will not be repeated here.

[0048] The above is a detailed introduction to a cover assembly, a single cell and a battery pack provided in the embodiments of the present application, and specific examples are used to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the technical solution and its core idea of ​​the present application; ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents; and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the present application.

Claims

1. A cover plate assembly, characterized in that: include: A cover plate, wherein the cover plate is provided with a pressure relief hole; An insulating member, the insulating member is connected to the cover plate, the insulating member faces the pressure relief hole, and the insulating member has a placement cavity; A support member, the support member is disposed in the placement cavity, and the melting point of the support member is greater than the melting point of the insulating member; A cover seal is used to seal the housing cavity.

2. The cover plate assembly according to claim 1, characterized in that: The insulating member and the cover seal are integrally formed, and the insulating member and the cover seal surround the placement cavity.

3. The cover plate assembly according to claim 1, characterized in that: The orthographic projection of the support member on the cover plate is at least partially located outside the pressure relief hole.

4. The cover plate assembly according to claim 1, characterized in that: The insulating member is provided with an exhaust hole, the exhaust hole is connected to the pressure relief hole, and the orthographic projection of the exhaust hole on the cover plate is at least partially located in the pressure relief hole.

5. The cover plate assembly according to claim 4, characterized in that: The insulating member is provided with a through hole for the electrode tab of the electrode assembly to pass through, and the through hole is located on a side of the supporting member away from the exhaust hole.

6. The cover plate assembly according to claim 1, characterized in that: The wall thickness of the insulating member wrapped around the outer side of the support member is a mm, satisfying: 0.7 mm ≥ a mm ≥ 0.5 mm; And / or, the wall thickness of the cover sealing member in a direction perpendicular to the support member is b mm, satisfying: 0.7 mm ≥ b mm ≥ 0.5 mm.

7. The cover plate assembly according to claim 1, characterized in that: The Rockwell hardness of the insulating component is c, satisfying: 90≥c≥60.

8. The cover plate assembly according to claim 1, characterized in that: The melting point of the support member is d°C, satisfying: d°C≥600°C.

9. A single cell battery, characterized in that: include: The cover plate assembly as described in any one of claims 1 to 8, further comprising a shell and an electrode assembly, the shell having a accommodating cavity and an opening connected to the accommodating cavity, the electrode assembly and the insulating member being arranged in the accommodating cavity, the cover plate covering the opening, and the insulating member being located between the cover plate and the electrode assembly.

10. A battery pack, characterized in that: include: The single cell battery as claimed in claim 9.

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