Cylindrical lithium battery combined cover and cylindrical lithium battery

Abstract

The utility model discloses a cylindrical lithium battery combination cap and cylindrical lithium battery, this cylindrical lithium battery combination cap includes sealing element, metal sheet, adhesive and top cover, sealing element is the tubular structure, and sealing element includes annular support part, metal sheet installs in the first surface of support part, top cover is the tubular structure, and top cover includes bottom wall, top wall and wall, and bottom wall is sealedly connected with the one side of metal sheet away from support part through adhesive, and the inner chamber of top cover forms the air chamber, metal sheet is equipped with first exhaust hole, and adhesive is equipped with second exhaust hole, and first exhaust hole is communicated with second exhaust hole to form exhaust passage, and exhaust passage and air chamber are interconnected, when the internal pressure of cylindrical lithium battery exceeds the set threshold value, the gas in cylindrical lithium battery enters the air chamber through exhaust passage, and the top cover is opened, realizes pressure relief, can effectively avoid the explosion of cylindrical lithium battery, fire, and puts an end to battery explosion and spouts, effectively improves the safety performance of cylindrical lithium battery.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a cylindrical lithium battery assembly cap and a cylindrical lithium battery. Background Technology

[0002] With the rapid development of new energy sources, lithium-ion batteries, as a type of recyclable, high-energy-density, and environmentally friendly secondary battery, have broad market application prospects. However, with the increase in energy density, their safety issues have gradually become a focus of attention. The battery cap, as a commonly used safety structure, not only serves a sealing function but also significantly impacts the safety performance during battery use and storage. In the event of thermal runaway, the traditional combined cap structure can cause a large amount of gas to be generated inside the battery due to the heat of reaction, leading to a sharp increase in internal pressure and potentially causing a blowout, thus increasing the battery's safety risks. Utility Model Content

[0003] The technical problem to be solved by this utility model is to provide a cylindrical lithium battery assembly cap and a cylindrical lithium battery.

[0004] The technical solution adopted by this utility model to solve its technical problem is: to construct a cylindrical lithium battery assembly cap, including a sealing element, a metal sheet, an adhesive element, and a top cover;

[0005] The sealing element has a cylindrical structure and includes an annular support portion. The support portion has a first surface and a second surface facing away from each other, and a limiting portion extends along the outer periphery of the support portion. The metal sheet is mounted on the first surface of the support portion. The top cover has a cylindrical structure and includes a bottom wall, a top wall, and a surrounding wall. The surrounding wall connects the bottom wall and the top wall. The bottom wall is sealed to the side of the metal sheet facing away from the support portion by the adhesive. The inner cavity of the top cover forms an air chamber.

[0006] The metal sheet is provided with a plurality of first vent holes, and the adhesive is provided with a plurality of second vent holes. The first vent holes and the second vent holes are connected in a one-to-one correspondence to form an exhaust channel, and the exhaust channel is connected to the air chamber.

[0007] In some embodiments, the number of the first exhaust holes is 4-6, and a plurality of the first exhaust holes are distributed in a ring along the axis of the metal sheet, with the hole spacing between adjacent first exhaust holes being 2mm-3mm;

[0008] The number of the second vent holes is 4-6, and several of the second vent holes are distributed in a ring along the axis of the adhesive, with the hole spacing between adjacent second vent holes being 2mm-3mm.

[0009] In some embodiments, the first vent is a circular hole with an inner diameter of 0.4mm-0.6mm;

[0010] The second exhaust port is a round hole with an inner diameter of 0.4mm-0.6mm.

[0011] In some embodiments, the outer periphery of the metal sheet extends toward the side away from the support portion and then bends toward the side away from the limiting portion to form a flange structure. The flange structure has a limiting groove, and a metal reinforcing member is provided in the limiting groove.

[0012] In some embodiments, the inner side of the limiting portion is provided with an annular protrusion, the protrusion and the supporting portion define a limiting space, and the flange structure is located within the limiting space.

[0013] In some embodiments, the metal sheet comprises an aluminum sheet.

[0014] In some embodiments, the metal reinforcement comprises a nickel-plated steel sheet.

[0015] In some embodiments, the thickness of the adhesive is 80μm-150μm.

[0016] In some embodiments, the adhesive is a conductive adhesive.

[0017] This utility model also discloses a cylindrical lithium battery, which includes a battery casing and a cylindrical lithium battery assembly cap as described in any of the above embodiments, and a battery cell disposed in the battery casing. The battery casing has a first end and a second end opposite to each other. The first end of the battery casing is an open structure, and the inner cavity of the first end of the battery casing forms an installation cavity. The cylindrical lithium battery assembly cap is sealed and installed in the installation cavity.

[0018] The present invention has the following beneficial effects: The cylindrical lithium battery assembly cap includes a sealing element, a metal sheet, an adhesive element, and a top cover; the sealing element has a cylindrical structure and includes an annular support portion, which has a first surface and a second surface facing away from each other, and a limiting portion extends along the outer periphery of the support portion; the metal sheet is installed on the first surface of the support portion; the top cover has a cylindrical structure and includes a bottom wall, a top wall, and a surrounding wall, the surrounding wall connecting the bottom wall and the top wall, the bottom wall being sealed to the side of the metal sheet facing away from the support portion through the adhesive element, and the inner cavity of the top cover forming a gas chamber; the metal sheet is provided with a plurality of first vent holes, and the adhesive element is provided with a plurality of second vent holes, the first vent holes and the second vent holes are connected one-to-one to form a venting channel, the venting channel and the gas chamber are interconnected, when the internal pressure of the cylindrical lithium battery exceeds a set threshold, the gas inside the cylindrical lithium battery enters the gas chamber through the venting channel and pushes open the top cover to achieve pressure relief, which can effectively prevent the cylindrical lithium battery from exploding or catching fire, eliminate battery explosion, and effectively improve the safety performance of the cylindrical lithium battery. Attached Figure Description

[0019] To more clearly illustrate the technical solution of this utility model, the present utility model will be further described below in conjunction with the accompanying drawings and embodiments. It should be understood that the following drawings only show some embodiments of this utility model and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort. In the drawings:

[0020] Figure 1 This is a three-dimensional structural schematic diagram of the cylindrical lithium battery assembly cap in some embodiments of this utility model;

[0021] Figure 2 This is a top view of the cylindrical lithium battery assembly cap in some embodiments of this utility model;

[0022] Figure 3 This is a cross-sectional view of the cylindrical lithium battery assembly cap in some embodiments of this utility model;

[0023] Figure 4 This is a schematic diagram of the pressure relief of the cylindrical lithium battery assembly cap in some embodiments of this utility model;

[0024] Figure 5 This is a schematic diagram of the structure of a cylindrical lithium battery in some embodiments of this utility model. Detailed Implementation

[0025] To provide a clearer understanding of the technical features, objectives, and effects of this utility model, the specific embodiments of this utility model are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the orientations or positional relationships indicated by terms such as "front," "rear," "upper," "lower," "left," "right," "longitudinal," "horizontal," "vertical," "horizontal," "top," "bottom," "inner," "outer," "head," and "tail" are based on the orientations or positional relationships shown in the accompanying drawings, and are constructed and operated in a specific orientation. They are only for the convenience of describing this technical solution and do not indicate that the device or component referred to must have a specific orientation; therefore, they should not be construed as limitations on this utility model.

[0026] It should also be noted that, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "joining," "fixing," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. When an component is referred to as being "on" or "below" another component, the component can be located "directly" or "indirectly" on the other component, or there may be one or more intermediary components. The terms "first," "second," "third," etc., are only for the convenience of describing this technical solution and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first," "second," "third," etc., may explicitly or implicitly include one or more of that feature. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0027] In the following description, specific details such as particular system structures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the present invention. However, those skilled in the art will understand that the present invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

[0028] See Figures 1 to 4 This utility model discloses a cylindrical lithium battery assembly cap 10, including a sealing element 11, a metal sheet 12, an adhesive element 13, and a top cover 14.

[0029] The seal 11 has a cylindrical structure and includes an annular support portion 111. The support portion 111 has a first surface and a second surface facing away from each other. A limiting portion 112 extends along the outer periphery of the support portion 111. The limiting portion 112 may be perpendicularly connected to the support portion 111.

[0030] The metal sheet 12 is mounted on the first surface of the support portion 111. The top cover 14 has a cylindrical structure, which may be a generally frustum-shaped cylindrical structure. The top cover 14 includes a bottom wall 141, a top wall 142, and a surrounding wall 143. The top wall 142 is parallel to and spaced apart from the bottom wall 141, and the top wall 142 and the bottom wall 141 are coaxially arranged. The surrounding wall 143 connects the bottom wall 141 and the top wall 142. The bottom wall 141 is sealed to the side of the metal sheet 12 away from the support portion 111 by the adhesive 13. The inner cavity of the top cover 14 forms an air chamber 14a. The height of the air chamber 14a can be 2.0mm-2.5mm, used to buffer gas pressure. The height of the air chamber 14a can be 2.0mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, or 2.5mm.

[0031] The metal sheet 12 is provided with a plurality of first vent holes 121, and the adhesive component 13 is provided with a plurality of second vent holes 131. The first vent holes 121 and the second vent holes 131 are connected in a one-to-one correspondence to form an exhaust channel. The exhaust channel is interconnected with the air chamber 14a. For example... Figure 4 As shown, when the internal pressure of the cylindrical lithium battery exceeds a set threshold (e.g., 2.0 MPa), the gas inside the cylindrical lithium battery enters the gas chamber 14a through the exhaust channel and pushes open the top cover 14 to release pressure. This can effectively prevent the cylindrical lithium battery from exploding or catching fire, eliminate battery blowout, and effectively improve the safety performance of the cylindrical lithium battery.

[0032] In some embodiments, the number of first vent holes 121 is 4-6, and a plurality of the first vent holes 121 are distributed in a ring along the axis of the metal sheet 12, with the hole spacing between adjacent first vent holes 121 being 2mm-3mm; similarly, the number of second vent holes 131 is 4-6, and a plurality of the second vent holes 131 are distributed in a ring along the axis of the adhesive 13, with the hole spacing between adjacent second vent holes 131 being 2mm-3mm.

[0033] In some embodiments, the first vent 121 is a circular hole with an inner diameter of 0.4mm-0.6mm, for example, the inner diameter of the first vent 121 is 0.4mm, 0.5mm, or 0.6mm. Similarly, the second vent 131 is a circular hole with an inner diameter of 0.4mm-0.6mm, for example, the inner diameter of the second vent 131 is 0.4mm, 0.5mm, or 0.6mm.

[0034] In some embodiments, the projections of all first vent holes 121 and all second vent holes 131 are located on the top wall 142.

[0035] In some embodiments, the seal 11 is made of an insulating material, thereby insulating the cylindrical lithium battery assembly cap 10 from the battery case 20. Further, the seal 11 may be a PP seal.

[0036] In some embodiments, the peel strength between the metal sheet 12 and the top cover 14 is ≥25N, ensuring sealing under normal operating conditions.

[0037] In some embodiments, the metal sheet 12, the adhesive 13, and the top cover 14 are all conductive components.

[0038] In some embodiments, the metal sheet 12 may include an aluminum sheet.

[0039] In some embodiments, the adhesive 13 is a conductive adhesive. Further, the adhesive 13 may be made of PP adhesive, with conductive fillers added during its fabrication. These conductive fillers include, but are not limited to, carbon black, metal nanoparticles, or carbon nanotubes. The addition of conductive fillers can form a conductive network within the PP adhesive.

[0040] The adhesive 13 can form a fully sealed structure with the metal sheet 12 and the top cover 14 through a hot-pressing composite process, ensuring the sealing between the metal sheet 12 and the top cover 14 and preventing electrolyte leakage. The hot-pressing temperature is 170℃-190℃. In some embodiments, the thickness of the adhesive 13 is 80μm-150μm, for example, the thickness of the adhesive 13 can be 80μm, 90μm, 100μm, 110μm, 120μm, 130μm, 140μm or 150μm.

[0041] In some embodiments, the top cover 14 does not have a vent structure; further, the top cover 14 may be a nickel-plated steel top cover.

[0042] For example Figure 3 As shown, in some embodiments, the outer periphery of the metal sheet 12 extends away from the support portion 111 and then bends away from the limiting portion 112 to form a flange structure 122. The flange structure 122 has a limiting groove, in which a metal reinforcing member 15 is provided to form a high-strength support. The limiting groove is annular, and the metal reinforcing member 15 is also generally annular. The metal reinforcing member 15 improves the mechanical strength and deformation resistance of the cylindrical lithium battery assembly cap 10.

[0043] Furthermore, the flange structure 122 may include a bent portion formed by one-time roll forming, with a bending angle of 90° and a flange height of 3mm-4mm, so as to form a mechanical fixed connection with the metal reinforcement 15.

[0044] In some embodiments, the inner side of the limiting portion 112 is provided with an annular protrusion 113, the protrusion 113 and the support portion 111 define a limiting space, and the flange structure 122 is located within the limiting space.

[0045] In some embodiments, the metal reinforcement 15 comprises a nickel-plated steel sheet. The metal reinforcement 15 can withstand a radial pressure of ≥50N to prevent the cylindrical lithium battery assembly cap 10 from deforming due to external impact.

[0046] In some embodiments, the method for preparing the cylindrical lithium battery assembly cap 10 includes the following steps:

[0047] Step S1: Stamp forming to manufacture the top cover 14, and no vent holes are provided on the top wall 142 and the surrounding wall 143 of the top cover 14.

[0048] Step S2: An adhesive 13 is applied to the bottom surface of the bottom wall 141 of the top cover 14, and a composite structure is formed by hot pressing.

[0049] Step S3: After stamping the metal sheet 12, specifically, the metal sheet 12 can be an aluminum sheet, which can be an aluminum strip with a thickness of 0.3mm-0.4mm, and is stamped into a circular shape; 4-6 first vent holes 121 with a diameter of 0.4mm-0.6mm are stamped in the central area of ​​the metal sheet 12, and the multiple first vent holes 121 are evenly distributed circumferentially. Further, the adhesive 13 is thermally bonded between the bottom wall 141 of the top cover 14 and the metal sheet 12 to form an air chamber 14a; wherein, the hot pressing pressure is 8MPa-12MPa, the holding time is 15-25 seconds, and the adhesive 13 (such as PP adhesive) melts to form a continuous, bubble-free sealed interface; 1.5MPa air pressure is applied to the encapsulated cylindrical lithium battery assembly cap 10, and the leakage rate is ≤0.03mL / min.

[0050] Step S4: Punch-cut the annular metal reinforcement 15. The metal reinforcement 15 can be a nickel-plated steel sheet. A nickel-plated steel sheet with a thickness of 0.5 mm can be selected. The metal reinforcement 15 is formed by punching, and the outer diameter is slightly smaller than the inner diameter of the metal sheet 12 after it is flanged.

[0051] Step S5: The metal sheet 12 is rolled over to cover the edge of the metal reinforcement 15 through a progressive rolling process, and then locked with the protrusion 113 of the seal to complete the assembly.

[0052] like Figure 5 As shown, this utility model also discloses a cylindrical lithium battery, which may be, but is not limited to, a lithium-ion battery, and may be, but is not limited to, batteries of specifications such as 18650 and 21700.

[0053] The cylindrical lithium battery may include a battery case 20 and a cylindrical lithium battery assembly cap 10, and a battery cell 30 disposed in the battery case 20. The battery case 20 has a first end and a second end opposite to each other. The first end of the battery case 20 is an open structure, and the inner cavity of the first end of the battery case 20 forms an installation cavity. The cylindrical lithium battery assembly cap 10 is sealed and installed in the installation cavity.

[0054] The cell 30 may include a positive electrode assembly and a negative electrode assembly. The positive electrode assembly and the negative electrode assembly may be wound together to form a cylindrical structure through a separator assembly. The positive electrode tab of the positive electrode assembly may be mechanically and electrically connected to the cylindrical lithium battery assembly cap 10. The negative electrode tab of the negative electrode assembly may be mechanically and electrically connected to the battery casing 20. The battery casing 20 may be, but is not limited to, a steel casing.

[0055] In some embodiments, after the cylindrical lithium battery is assembled, it is tested. Specifically, after the assembled cylindrical lithium battery assembly cap 10 and battery case 20 are sealed together, the sealing performance of the metal sheet 12 and the top cover 14 is tested: 1.5 MPa air pressure is injected from the bottom of the battery case 20 to apply gas pressure to the packaged cylindrical lithium battery assembly cap 10, and the leakage rate is ≤0.03 mL / min; safety pressure test: when the simulated internal pressure of the cylindrical lithium battery rises to 2.0 MPa, the top cover 14 should be able to smoothly detach from the metal sheet 12 to achieve pressure relief.

[0056] When the cylindrical lithium battery assembly cap 10 is applied, when the internal pressure of the cylindrical lithium battery increases due to abnormal gas generation, for example, when the internal gas pressure of the cylindrical lithium battery increases suddenly due to abnormal operating conditions such as short circuit or overcharge, the gas enters the gas chamber 14a of the top cover 14 through the first vent 121 of the metal sheet 12 and the second vent 131 of the adhesive 13. When the pressure reaches a set threshold such as 2.0 MPa, the top cover 14 is opened, and the gas is released instantly. The pressure relief response time is ≤10ms, thereby preventing the cylindrical lithium battery from exploding or catching fire.

[0057] It is understood that the above embodiments only illustrate preferred embodiments of the present utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present utility model patent. It should be noted that for those skilled in the art, the above technical features can be freely combined, and several modifications and improvements can be made without departing from the concept of the present utility model, all of which fall within the protection scope of the present utility model. Therefore, all equivalent transformations and modifications made within the scope of the claims of the present utility model should fall within the coverage of the claims of the present utility model.

Claims

1. A cap for a cylindrical lithium battery assembly, characterized in that, Includes a seal (11), a metal sheet (12), an adhesive (13), and a top cover (14); The sealing element (11) has a cylindrical structure and includes an annular support portion (111). The support portion (111) has a first surface and a second surface facing away from each other. A limiting portion (112) extends along the outer periphery of the support portion (111). The metal sheet (12) is mounted on the first surface of the support portion (111). The top cover (14) has a cylindrical structure and includes a bottom wall (141), a top wall (142), and a surrounding wall (143). The surrounding wall (143) connects the bottom wall (141) and the top wall (142). The bottom wall (141) is sealed to the side of the metal sheet (12) facing away from the support portion (111) by the adhesive (13). The inner cavity of the top cover (14) forms an air chamber (14a). The metal sheet (12) is provided with a plurality of first exhaust holes (121), and the adhesive (13) is provided with a plurality of second exhaust holes (131). The first exhaust holes (121) and the second exhaust holes (131) are connected one-to-one to form an exhaust channel, and the exhaust channel is connected to the air chamber (14a).

2. The cylindrical lithium battery assembly cap according to claim 1, characterized in that, The number of the first exhaust holes (121) is 4-6, and several of the first exhaust holes (121) are distributed in a ring along the axis of the metal sheet (12), and the hole spacing between adjacent first exhaust holes (121) is 2mm-3mm; The number of the second vent holes (131) is 4-6, and several of the second vent holes (131) are distributed in a ring along the axis of the adhesive (13), and the hole spacing between adjacent second vent holes (131) is 2mm-3mm.

3. The cylindrical lithium battery assembly cap according to claim 2, characterized in that, The first vent hole (121) is a round hole, and the inner diameter of the first vent hole (121) is 0.4mm-0.6mm; The second exhaust hole (131) is a round hole with an inner diameter of 0.4mm-0.6mm.

4. The cylindrical lithium battery assembly cap according to claim 1, characterized in that, The outer periphery of the metal sheet (12) extends toward the side away from the support (111) and then bends toward the side away from the limiting part (112) to form a flange structure (122). The flange structure (122) has a limiting groove, and a metal reinforcing member (15) is provided in the limiting groove.

5. The cylindrical lithium battery assembly cap according to claim 4, characterized in that, The inner side of the limiting part (112) is provided with an annular protrusion (113), and the protrusion (113) and the support part (111) define a limiting space, and the flange structure (122) is located in the limiting space.

6. The cylindrical lithium battery assembly cap according to any one of claims 1 to 5, characterized in that, The metal sheet (12) includes an aluminum sheet.

7. The cylindrical lithium battery assembly cap according to claim 4, characterized in that, The metal reinforcement (15) includes a nickel-plated steel sheet.

8. The cylindrical lithium battery assembly cap according to claim 1, characterized in that, The thickness of the adhesive (13) is 80μm-150μm.

9. The cylindrical lithium battery assembly cap according to claim 1, characterized in that, The adhesive (13) is a conductive adhesive.

10. A cylindrical lithium battery, characterized in that, The battery housing (20) includes a cylindrical lithium battery assembly cap as described in any one of claims 1 to 9, and a battery cell (30) disposed within the battery housing (20). The battery housing (20) has a first end and a second end opposite to each other. The first end of the battery housing (20) is an open structure, and the inner cavity of the first end of the battery housing (20) forms an installation cavity. The cylindrical lithium battery assembly cap is sealed and installed within the installation cavity.

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