WO2022105140A1

WO2022105140A1 - Secondary battery top cover assembly and secondary battery

Info

Publication number: WO2022105140A1
Application number: PCT/CN2021/091746
Authority: WO
Inventors: 王有生; 覃太平; 李华; 远浩; 夏春文
Original assignee: 常州瑞德丰精密技术有限公司
Priority date: 2020-11-19
Filing date: 2021-04-30
Publication date: 2022-05-27
Also published as: CN112234309A

Abstract

A secondary battery top cover assembly (100) and a secondary battery. The secondary battery top cover assembly (100) comprises: a cover plate (10) provided with an explosion-proof hole (11); a first abutting part (12) arranged on an inner wall of the explosion-proof hole (11) in a protruding manner, wherein the first abutting part (12) is arranged in the circumferential direction of the explosion-proof hole (11); an explosion-proof sheet (30) abutting against the first abutting part (12), wherein the explosion-proof sheet (30) seals the explosion-proof hole (11), and the explosion-proof sheet (30) is made of plastic; and a fastener (20) abutting against an edge of the explosion-proof sheet (30), wherein the fastener (20) is provided with a through hole (201), and the explosion-proof sheet (30) is exposed from the through hole (201). The metal material of an existing metal explosion-proof sheet is replaced with the plastic explosion-proof sheet (30), and the explosion-proof sheet (30) is fixed on the cover plate (10) of a top cover by means of the fastener (20) provided with the through hole (201), such that the explosion-proof sheet (30) is exposed from the through hole (201). Thus, when the gas pressure in the battery reaches a certain value, the explosion-proof sheet (30) separates from the edge, thereby achieving the aim of pressure relief, so that the problem of fluctuations in the opening pressure of the explosion-proof sheet (30) caused by welding is avoided, and the safety performance of the secondary battery is improved.

Description

Secondary battery top cover assembly and secondary battery

technical field

The present application relates to the technical field of energy storage devices, and in particular, to a secondary battery top cover assembly and a secondary battery.

Background technique

With the development of more and more power tools and new energy vehicles in the direction of high capacity and high safety, secondary batteries are widely used in power tools and new energy vehicles due to their excellent characteristics such as high capacity. middle.

The secondary battery can be charged and discharged, and its interior is a relatively sealed environment. In the event of a short-circuit failure caused by overcharging or being punctured, a large amount of heat and gas will be rapidly generated inside the secondary battery and accumulate inside the cell. As a result, the internal pressure of the secondary battery increases, and when the internal pressure reaches a preset pressure value, the secondary battery may expand and explode, which may lead to safety problems of the secondary battery. In order to ensure the safety of the secondary battery, an explosion-proof valve assembly is generally arranged on the top cover of the secondary battery to prevent the secondary battery from exploding. In the prior art, the explosion-proof valve assembly is provided with a metal explosion-proof disc. The metal explosion-proof disc is welded on the top cover, and the explosion-proof disc is provided with a notch. Since the notch is thinner than other parts on the explosion-proof disc, when the battery cell is abnormal When , the gas generated in the battery cell first punches out the notch area, so as to achieve the purpose of releasing pressure and heat, and avoid the explosion of the secondary battery.

technical problem

Since the metal explosion-proof disc in the explosion-proof valve assembly of the current secondary battery is welded on the top cover, due to the deformation of the top cover plate or the inconsistent welding strength, the opening pressure of the explosion-proof disc may fluctuate, thereby affecting the performance of the secondary battery. safety performance.

technical solutions

The present application provides a secondary battery top cover assembly and a secondary battery, so as to solve the problem that the explosion pressure of the explosion-proof valve of the secondary battery has a large fluctuation range.

In one aspect, the present application provides a secondary battery top cover assembly, comprising:

Cover plate with explosion-proof holes;

the first abutting part is protrudingly arranged on the inner wall of the explosion-proof hole, and the first abutting part is arranged along the circumferential direction of the explosion-proof hole;

an explosion-proof disc abutting on the first abutting portion, the explosion-proof disc sealing the explosion-proof hole, and the explosion-proof disc being made of plastic;

The fastener is in contact with the edge of the explosion-proof disc, the fastener is provided with a through hole, and the explosion-proof disc is exposed through the through hole.

In a possible implementation manner of the present application, the rupture disk is made of fluorinated ethylene propylene copolymer or soluble polytetrafluoroethylene.

In a possible implementation manner of the present application, the thickness of the explosion-proof disk ranges from 0.5 mm to 1.5 mm.

In a possible implementation manner of the present application, the secondary battery top cover assembly further includes:

A protrusion is arranged on the first abutting portion, and the explosion-proof disc is abutted on the protrusion.

In a possible implementation manner of the present application, the number of the protrusions is multiple, the multiple protrusions are arranged at intervals, and the distance between the adjacent protrusions ranges from 0.5 mm to 1 mm.

In a possible implementation manner of the present application, the inner side wall of the first abutting portion is flush with the side surface of the protrusion, and the side surface is the inner side surface of the protrusion close to the center of the explosion-proof hole.

In a possible implementation manner of the present application, the fasteners include:

A welding piece is welded with the inner wall of the explosion-proof hole, and the through hole is located on the welding piece.

In a possible implementation manner of the present application, the distance between the inner side wall of the first abutting part and the inner side surface of the welding part ranges from 0 to 0.3 mm, and the distance is the first contact The inner side wall of the part protrudes toward the center of the explosion-proof hole by a distance from the inner side surface of the welding piece.

In a possible implementation manner of the present application, one of the first abutting portion or the rupture disk is provided with a connecting portion, and the other is provided with an embedded portion embedded in the connecting portion.

In a possible implementation manner of the present application, the fastener further includes:

The sealing ring is detachably connected to the inner wall of the explosion-proof hole, the sealing ring is arranged between the welding piece and the explosion-proof disc, and the ring hole of the sealing ring is communicated with the through hole.

In a possible implementation manner of the present application, the sealing ring is provided with a first clamping groove, the welding member is provided with a second clamping groove, and the sealing ring and the welding member pass through the first clamping groove. The slot and the second card slot are engaged with each other.

In a possible implementation manner of the present application, the inner wall of the explosion-proof hole is further provided with a second abutting portion, the second abutting portion and the first abutting portion are arranged in steps, and the fastener At least part of the outer edge of the abutting portion is in contact with the second abutting portion.

In a possible implementation manner of the present application, the secondary battery top cover assembly further includes: a protection sheet, disposed on the side of the cover plate facing away from the protrusion, and the protection sheet covers the explosion-proof cover hole.

On the other hand, the present application also provides a secondary battery, comprising: a battery cell, a casing and the secondary battery top cover assembly, the battery core is assembled in the casing, the secondary battery top cover The assembly caps the housing.

beneficial effect

In the secondary battery top cover assembly and the secondary battery provided by the present application, the metal material of the existing explosion-proof disc is replaced with a plastic material, and the explosion-proof disc is fixed on the cover plate of the top cover through fasteners with through holes. , so that the explosion-proof disc is exposed in the through hole, so that when the air pressure inside the battery reaches a certain value, the explosion-proof disc is detached from the edge, so that the gas is discharged from the inside of the battery through the through hole to the outside of the battery, so as to achieve the purpose of pressure relief, so as to avoid Due to the problem of the opening pressure fluctuation of the explosion-proof disc caused by welding, the stability of the burst value is ensured and the safety performance of the secondary battery is improved. At the same time, the use of plastic explosion-proof disc is also conducive to reducing the secondary The manufacturing cost of the battery top cover.

Description of drawings

The technical solutions and other beneficial effects of the present application will be apparent through the detailed description of the specific embodiments of the present application in conjunction with the accompanying drawings.

FIG. 1 is a schematic diagram of an assembly structure of a secondary battery provided by an embodiment of the present application.

FIG. 2 is a schematic exploded structural diagram of the top cover assembly of the secondary battery of FIG. 1 according to an embodiment of the present application.

FIG. 3 is a schematic cross-sectional structural diagram of the top cover assembly of the secondary battery of FIG. 1 according to an embodiment of the present application.

FIG. 4 is a partial enlarged schematic diagram of A in FIG. 3 according to an embodiment of the present application.

FIG. 5 is a schematic cross-sectional view of yet another embodiment of the protrusion provided by the present application.

FIG. 6 is a partial enlarged schematic diagram of B in FIG. 5 according to an embodiment of the present application.

FIG. 7 is a schematic diagram of an assembly structure of a secondary battery according to another embodiment of the present application.

FIG. 8 is a schematic cross-sectional view of the top cover assembly of the secondary battery of FIG. 7 according to an embodiment of the present application.

FIG. 9 is a schematic structural diagram of a protective patch assembly of a top cover of a battery according to an embodiment of the present application.

BEST MODE FOR CARRYING OUT THE INVENTION

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not 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 fall within the protection scope of the present application.

In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", " rear, left, right, vertical, horizontal, top, bottom, inside, outside, clockwise, counterclockwise, etc., or The positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, Therefore, it should not be construed as a limitation on this application. In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, features defined as "first", "second" may expressly or implicitly include one or more of said features. In the description of the present application, "plurality" means two or more, unless otherwise expressly and specifically defined.

In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it may be a fixed connection or a detachable connection Connection, or integral connection; it can be a mechanical connection, an electrical connection or can communicate with each other; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal communication of two elements or the interaction of two elements relation. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific situations.

In this application, unless otherwise expressly specified and defined, a first feature "on" or "under" a second feature may include direct contact between the first and second features, or may include the first and second features Not directly but through additional features between them. Also, the first feature being "above", "over" and "above" the second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is level higher than the second feature. The first feature is "below", "below" and "below" the second feature includes the first feature being directly below and diagonally below the second feature, or simply means that the first feature has a lower level than the second feature.

The following disclosure provides many different embodiments or examples for implementing different structures of the present application. To simplify the disclosure of the present application, the components and arrangements of specific examples are described below. Of course, they are only examples and are not intended to limit the application. Furthermore, this application may repeat reference numerals and/or reference letters in different instances for the purpose of simplicity and clarity, and does not in itself indicate a relationship between the various embodiments and/or arrangements discussed. In addition, this application provides examples of various specific processes and materials, but one of ordinary skill in the art will recognize the application of other processes and/or the use of other materials.

Please refer to FIG. 1 , which is a schematic diagram of the assembly structure of the secondary battery provided by the present application. The secondary battery of the present application includes: a battery cell (not shown in the figure), a casing 200 and a secondary battery top cover assembly 100 . The assembly 100 covers the casing 200 , and at the same time, the battery top cover assembly 100 is electrically connected with the cells to assist in introducing electric energy into the cells or exporting the energy in the cells.

The embodiment of the present application provides a secondary battery top cover assembly 100 , please refer to FIGS. 2 to 4 , the secondary battery top cover assembly 100 includes: a cover plate 10 , a first abutting portion 12 , a protrusion 40 , and a bursting disc 30 and fasteners 20.

The cover plate 10 is provided with an explosion-proof hole 11 . The cover plate 10 can be made of, for example, aluminum or aluminum alloy. Generally, as shown in FIG. 2 , the cover plate 10 is further provided with a positive pole 70 , a negative pole 80 and a liquid injection hole 90 .

The first abutting portion 12 is protruded on the inner wall of the explosion-proof hole 11 , and the first abutting portion 12 is disposed along the circumferential direction of the explosion-proof hole. In this embodiment, the first abutting portion 12 is arranged in an annular structure, and the first abutting portion 12 and the explosion-proof hole 11 are in the shape of a stepped hole. The explosion-proof disc 30 abuts on the first abutting portion 12 , the explosion-proof disc 30 seals the explosion-proof hole 11 , and the explosion-proof disc 30 is made of plastic material.

The fastener 20 abuts on the edge of the rupture disk 30, the fastener 20 is provided with a through hole 201, the rupture disk 30 is exposed in the through hole 201, and the arrangement of the fastener 20 can compress the rupture disk 30, so that The explosion-proof disc 30 is closely attached to the first abutment portion 12 to better ensure the gas sealing of the explosion-proof hole. Meanwhile, the through hole 201 can ensure that the gas can be discharged smoothly after breaking through the explosion-proof disc 30 when thermal runaway occurs inside the battery. outside the battery, so as to achieve the purpose of releasing pressure and heat.

The secondary battery top cover assembly provided by the embodiment of the present application replaces the metal material of the existing explosion-proof disc with a plastic material, and fixes the explosion-proof disc on the cover plate of the top cover through fasteners with through holes, so that the explosion-proof The sheet is exposed in the through hole, so that when the air pressure inside the battery reaches a certain value, the explosion-proof disc is separated from the first abutting part from its edge, so that the explosion-proof disc no longer seals the explosion-proof hole, so that the gas is discharged from the inside of the battery through the through hole. external, so as to achieve the purpose of pressure relief, so as to avoid the opening pressure fluctuation of the explosion-proof disc caused by welding, thereby ensuring the stability of the burst value and improving the safety performance of the secondary battery top cover assembly. At the same time, the plastic material is used. Compared with the metal rupture disk, the rupture disk is also beneficial to reduce the manufacturing cost of the top cover of the secondary battery.

In some embodiments, the rupture disk 30 is made of fluorinated ethylene propylene copolymer (FEP) or soluble polytetrafluoroethylene (PFA). FEP or PFA has the characteristics of corrosion resistance, wear resistance, good sealing, etc., so it is suitable for the manufacture of rupture disks. When the battery fails, under the condition that the inside of the battery is slowly heated up, the explosion-proof disc 30 will be gradually deformed by heat in the process of temperature increase, and the explosion-proof disc 30 will be separated from the first abutting portion 12 at the edge, so that the explosion-proof disc 30 will no longer seal the explosion-proof hole 11 . , so that the gas inside the battery is discharged, thereby achieving the purpose of releasing heat and pressure; in the case of a high temperature inside the battery, the temperature instantly exceeds a certain temperature, such as the melting point of FEP or PFA, at this time, the explosion-proof disc 30 is melted and decomposed, thereby making explosion-proof The sheet is melted and blasted to achieve the purpose of releasing heat. In addition, FEP and PFA are relatively cheap compared to metal materials such as aluminum and copper. Therefore, compared with the use of metal explosion-proof discs in the prior art, the use of plastic-material explosion-proof discs is beneficial to reduce the manufacturing cost of the top cover of the secondary battery. Since the material of the rupture disk 30 affects the maximum temperature it can withstand, the higher the melting point of the material of the rupture disk 30, the higher the maximum temperature that the rupture disk 30 can withstand, that is, the material of the rupture disk 30 determines the warning of the secondary battery. The maximum temperature, so that the purpose of temperature monitoring can be achieved by setting the rupture disk 30 to different materials.

In some embodiments, the thickness of the rupture disk 30 ranges from 0.5 mm to 1.5 mm. For example, 0.5mm, 0.7mm, 1mm, 1.5mm, etc., the thickness of the explosion-proof disc 30 affects the maximum pressure it can bear, and the greater the thickness of the explosion-proof disc 30, the greater the maximum pressure it can bear. Since the thickness of the rupture disk 30 is determined by the maximum pressure warning of the secondary battery, the purpose of pressure monitoring is achieved by setting the thickness of the rupture disk 30 .

Please refer to FIG. 2 , FIG. 3 and FIG. 4 , the secondary battery top cover assembly provided by the present application further includes a protrusion 40 , the protrusion 40 is disposed on the first abutting portion 12 , and the explosion-proof disc 30 abuts against the protrusion on 40. The setting of the protrusions 40 will affect the maximum pressure that the rupture disk 30 can bear, and the pressure threshold of the rupture disk can be controlled by the protrusions 40, so as to further achieve the purpose of pressure monitoring.

The side surface of the protrusion 40 is flush with the side wall of the first abutting portion 12, and the side surface is the inner side surface of the protrusion 40 close to the center of the explosion-proof hole 11, so that the cross-sectional shape of the protrusion 40 is a right-angled trapezoid, wherein , the angle range of the vertex angle between the hypotenuse of the right-angled trapezoid and the upper base is 93°-95°, for example, the angle of the vertex angle can be 93°, 94° or 95°, etc. The inclination of the mold is beneficial to the convex part can be smoothly ejected and separated from the mold, which is convenient for processing.

It can be understood that the shape of the cross-section of the protrusion 40 can also be, for example, a square, a rectangle, an isosceles trapezoid, etc., all of which can achieve the purpose of the present application, which is not limited herein.

With reference to FIGS. 5 and 6 , the number of protrusions 40 may be multiple, and by setting multiple protrusions 40 , the range of the bursting threshold of the rupture disk 30 can be better controlled according to actual needs. The greater the number of protrusions 40, the greater the friction between the surface of the first abutting portion 12 and the rupture disk 30, the greater the bursting threshold of the rupture disk 30, the smaller the number of protrusions 40, the greater the resistance of the rupture disk 30. The smaller the blasting threshold is, therefore, the adjustment and control of the blasting threshold of the air pressure inside the casing 200 can be realized by setting the number of the protrusions 40 .

The plurality of protrusions 40 are arranged at intervals, and the spacing between adjacent protrusions 40 ranges from 0.5 mm to 1 mm. The burst threshold of the rupture disk 30 can be further adjusted by setting the number of the protrusions 40 and the distance between the protrusions 40, so as to achieve the purpose of pressure monitoring.

When the number of the protrusions 40 is multiple, there are various ways to arrange the multiple protrusions 40. For example, the first protrusion may be a right-angled trapezoid, and both the second protrusion and the third protrusion may be an isosceles trapezoid. The first protrusion is a protrusion whose side is flush with the side wall of the first abutting portion 12 , the side is the inner side of the protrusion 40 close to the center of the explosion-proof hole 11 , the second protrusion and the third protrusion are It is a protrusion that is successively away from the side wall of the first abutting portion 12 . Of course, the arrangement of the protrusions 40 may also be that the first protrusions, the second protrusions and the third protrusions are all rectangular, etc., which are not specifically limited herein.

Wherein, the protrusion 40 and the first abutting portion 12 may be integrally formed. The integrated molding design facilitates the processing and molding of the battery top cover assembly, which is conducive to saving processes.

There are various ways for the fastener 20 to fix the rupture disk 30. For example, the rupture disk 30 can be fixed on the first abutting portion 12 by welding the fastener 20 and the cover plate 10, or by attaching the fastener 20 to the cover plate 10. The rupture disk 30 can be fixed by screwing the fastener 20 to the first abutting portion 12 , or the rupture disk 30 can be fixed by bonding the fastener 20 to the inner wall of the explosion hole 11 , etc., which are not specifically limited here. .

In some embodiments, as shown in FIGS. 2-4 , the fastener 20 includes a welding piece 21 , the through hole 201 is located on the welding piece 21 , and the welding piece 21 abuts against the edge of the explosion-proof disk 30 . The welding piece 21 can be, for example, a welding ring, the welding ring 21 abuts against the edge of the rupture disk 30 so that the rupture disk 30 is tightly connected with the first abutting portion 12 , and the welding ring 21 is annular so that the rupture disk 30 is exposed to the welding ring In the annular through hole 201 of 21 , it can be ensured that when thermal runaway occurs inside the battery, the gas can be smoothly discharged out of the battery after breaking through the explosion-proof disk 30 , so as to achieve the purpose of releasing pressure and releasing heat. Wherein, the welding method may be laser welding, and certainly may also be welding by carbon dioxide shielded welding or the like. By welding the welding ring 21 to the inner wall of the explosion-proof hole 11 , the connection between the welding ring 21 and the cover plate 10 can be made tighter, which is beneficial to improve the stability of the explosion-proof disc 30 .

Further, the welding ring 21 is flush with the inner surface of the cover plate 10 , wherein the inner surface is the side facing the casing 200 . The welding ring 21 is flush with the inner surface of the cover plate 10 , which facilitates the welding process of the welding ring 21 and the cover plate 10 , and also helps to make the explosion-proof valve more beautiful.

In some embodiments, the distance between the inner side wall of the first abutting portion 12 and the inner side surface of the welding ring 21 ranges from 0 to 0.3 mm. Specifically, the distance between the inner side wall of the first abutting portion 12 and the welding ring 21 The distance between the inner side surfaces is specifically the distance that the inner side wall of the first abutting portion 12 protrudes from the inner side surface of the welding ring 21 toward the center of the explosion-proof hole 11 . For example, the distance between the inner side wall of the first abutting portion 12 and the inner side surface of the welding ring 21 may be 0, that is, the inner side wall of the first abutting portion 12 is aligned with the inner side surface of the welding ring 21, or both The distance between can also be 0.3mm. As shown in FIG. 4 , since the force of the inner edge of the welding ring 21 received by the rupture disk 30 is opposite to the force received by the protrusion 40 , when the side surface of the protrusion 40 is flush with the side wall of the first abutting portion 12 , and When the distance between the inner side wall of the first abutting portion 12 and the welding ring 21 is small, the force of the inner edge of the welding ring 21 received by the rupture disk 30 and the force received by the protrusion 40 are on the same line. The problem that the end of the rupture disk 30 is lifted due to the force on the rupture disk 30 is not on the same line is avoided, thereby ensuring the good sealing performance of the rupture disk 30 .

In some embodiments, the fastener 20 further includes a sealing ring 22, the sealing ring 22 is detachably connected to the inner wall of the explosion-proof hole 11, the sealing ring 22 is arranged between the welding ring 21 and the explosion-proof disc 30, and the ring hole of the sealing ring 22 and the inner wall of the explosion-proof hole 11 are detachably connected. The through holes 201 communicate with each other. Among them, the sealing ring 22 can be a rubber sealing ring, and the setting of the sealing ring 22 is beneficial to improve the sealing performance and stability of the explosion-proof valve. This is beneficial to prevent electrolyte leakage or external water vapor from entering the casing 200 in the normal working state of the secondary battery, thereby increasing the safety performance and service life of the secondary battery.

In some embodiments, the sealing ring 22 is provided with a first clamping groove 221 , the welding ring 21 is provided with a second clamping groove 211 , and the sealing ring 22 and the welding ring 21 are mutually connected through the first clamping groove 221 and the second clamping groove 211 . snap. Specifically, as shown in FIG. 6 , the opening directions of the second slot 211 and the second slot 221 are opposite, the outer edge of the sealing ring 22 is at least partially placed in the first slot 221, and the inner edge of the welding ring 1 at least partially is placed in the second card slot 211 . The welding ring 21 is welded on the cover plate 11, and the sealing ring 22 and the welding ring 21 are engaged with each other, so that the sealing ring 22 is pressed against the explosion-proof disc 30, so that the explosion-proof disc 30 and the protrusion 40 can be more closely combined , to better ensure the air tightness of the explosion-proof hole 11 , which is beneficial to increase the safety performance and service life of the secondary battery.

In some embodiments, the inner wall of the explosion-proof hole 11 is further provided with a second abutting portion 13 , the second abutting portion 13 and the first abutting portion 12 are arranged in steps, and the outer edge of the welding ring 21 at least partially abuts the second abutting portion 12 . The contact portion 13 abuts, and the setting of the second contact portion 13 can increase the contact surface between the welding ring 21 and the cover plate 10 , make the welding ring 21 and the cover plate 10 more stable, and facilitate the welding process between the welding ring 21 and the cover plate 10 realization.

Of course, in some embodiments, the explosion-proof disc 30 may also have other fixing methods in the explosion-proof hole 11 of the cover plate 10 . As shown in FIG. 7 , one of the first abutting portion 12 or the explosion-proof disc 30 is provided with The other connecting portion 52 is provided with a fitting portion 51 that is fitted into the connecting portion 52 . Since the embedded part 51 and the connecting part 52 cooperate to play a limiting role, when the embedded part 51 is subjected to external force, it is not easy to come out or move from the connecting part 52. Therefore, the first abutting part 12 and the explosion-proof disc 30 pass through the embedded part. The connection and fixation method can effectively improve the connection stability between the first abutting portion 12 and the explosion-proof disc 30 .

The connecting portion 52 may be a connecting hole. Specifically, as shown in FIG. 8 , taking the connecting portion as a connecting hole as an example, the first abutting portion 12 is provided with a plurality of connecting holes 52 . A plurality of embedded portions 51 embedded in the connecting holes 52 are provided, and the connecting holes 52 and the embedded portions 51 are in one-to-one correspondence. The explosion-proof disc 30 is made of plastic material, and the cover plate 10 and the first abutting portion 12 are made of metal material. The embedded portion 51 may be formed by injection molding. During injection molding, a part of the plastic of the explosion-proof disc 30 is filled into the connecting hole 52 of the first abutting part, and the embedded part 51 is formed after the plastic solidifies, so that the first abutting part 12 and the explosion-proof disc 30 form a whole. Thus, the connection strength between the first abutting portion 12 and the bursting disc 30 is ensured, and the connection stability is further improved.

The number of connection holes 52 can be set in multiples, for example, 4, 6 or 8. The more the number of connection holes 52 is, the greater the bonding strength between the first abutting portion 12 and the explosion-proof disc 30 is. , the greater the bursting threshold of the bursting disc 30 is, and similarly, when the number of connecting holes 52 is small, the bonding strength between the first abutting portion 12 and the bursting disc 30 is smaller, and the bursting threshold of the bursting disc 30 is smaller. , therefore, the adjustment and control of the blasting threshold of the internal pressure of the casing 200 can be achieved by setting the number of the connection holes 52 , and the pressure monitoring can be better achieved.

Of course, those skilled in the art can understand that the connecting portion 52 can also be a connecting groove, which can also achieve the purpose of the present application, which is not limited herein.

The secondary battery top cover assembly provided by the embodiment of the present application further includes a protection sheet 60. As shown in FIG. 9, the protection sheet 60 is disposed on the side of the cover plate 10 facing away from the protrusion 40, and the protection sheet 60 covers the explosion-proof hole. 11. The protection patch 60 may be made of polyvinyl chloride (PVC) material, and the protection patch 60 is pasted on the cover plate by means of bonding and covers the explosion-proof hole 11 . The arrangement of the protection sheet 60 can not only prevent foreign objects from pressing the rupture disk 30, but also protect the rupture disk 30 from the pollution of the external environment.

In the above-mentioned embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

The top cover assembly for a secondary battery and the secondary battery provided by the embodiments of the present application have been described in detail above. The principles and implementations of the present application are described with specific examples. The descriptions of the above embodiments are only used for To help understand the technical solutions of the present application and their core ideas; those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these Modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Embodiments of the present invention

Type the paragraphs describing embodiments of the invention here.

Industrial Applicability

Type an industrial applicability description paragraph here.

Sequence Listing Free Content

Type the Sequence Listing free content description paragraph here.

Claims

A secondary battery top cover assembly, characterized in that, comprising:

Cover plate with explosion-proof holes;

the first abutting part is protrudingly arranged on the inner wall of the explosion-proof hole, and the first abutting part is arranged along the circumferential direction of the explosion-proof hole;

an explosion-proof disc abutting on the first abutting portion, the explosion-proof disc sealing the explosion-proof hole, and the explosion-proof disc being made of plastic;

The fastener is in contact with the edge of the explosion-proof disc, the fastener is provided with a through hole, and the explosion-proof disc is exposed through the through hole.
The secondary battery top cover assembly of claim 1, wherein the rupture disk is made of fluorinated ethylene propylene copolymer or soluble polytetrafluoroethylene.
The top cover assembly of the secondary battery of claim 1, wherein the thickness of the rupture disk is in the range of 0.5 mm to 1.5 mm.
The secondary battery top cover assembly of claim 1, wherein the secondary battery top cover assembly further comprises:

A protrusion is arranged on the first abutting portion, and the explosion-proof disc is abutted on the protrusion.
The secondary battery top cover assembly according to claim 4, wherein the number of the protrusions is plural, the plurality of protrusions are arranged at intervals, and the distance between adjacent protrusions ranges from 0.5 mm to 0.5 mm. 1 mm.
The secondary battery top cover assembly according to claim 4 or 5, wherein the inner side wall of the first abutting portion is flush with the side surface of the protrusion, and the side surface is close to the explosion-proof hole. The raised inner side of the center.
The secondary battery top cover assembly of claim 6, wherein the fastener comprises:

A welding piece is welded with the inner wall of the explosion-proof hole, and the through hole is located on the welding piece.
8. The secondary battery top cover assembly according to claim 7, wherein the distance between the inner side wall of the first abutting part and the inner side surface of the welding part ranges from 0 to 0.3 mm, and the distance is 0 to 0.3 mm. is the distance by which the inner side wall of the first abutting portion protrudes from the inner side surface of the welding piece toward the center of the explosion-proof hole.
The top cover assembly for a secondary battery according to claim 1, wherein one of the first abutting portion or the rupture disk is provided with a connecting portion, and the other is provided with a connecting portion embedded in the connecting portion. Embedded Department.
The secondary battery top cover assembly of claim 7 or 9, wherein the fastener further comprises:

The sealing ring is detachably connected to the inner wall of the explosion-proof hole, the sealing ring is arranged between the welding piece and the explosion-proof disc, and the ring hole of the sealing ring is communicated with the through hole.
The secondary battery top cover assembly according to claim 10, wherein the sealing ring is provided with a first clamping groove, the welding member is provided with a second clamping groove, and the sealing ring and the welding part are provided with a first clamping groove. The components are engaged with each other through the first card slot and the second card slot.
The secondary battery top cover assembly according to claim 1, wherein the inner wall of the explosion-proof hole is further provided with a second abutting portion, and the second abutting portion and the first abutting portion present a step It is provided that the outer edge of the fastener at least partially abuts the second abutting portion.
The secondary battery top cover assembly of claim 1, wherein the secondary battery top cover assembly further comprises:

The protection sheet is arranged on the side of the cover plate facing away from the protrusion, and the protection sheet covers the explosion-proof hole.
A secondary battery, comprising: a battery cell, a casing and a secondary battery top cover assembly, the secondary battery top cover assembly being the secondary battery top cover according to any one of claims 1-13 The battery cell is assembled in the casing, and the secondary battery top cover assembly covers the casing.