Cap assembly and battery cell

Abstract

A cap assembly and a battery cell. The cap assembly comprises a sealing sleeve (100) and a top cap (200). The sealing sleeve (100) comprises a support portion (110) and an insulating portion (120), wherein the insulating portion (120) encloses the circumferential edge of the support portion (110); the support portion (110) is provided with a first through hole (111), and the top cap (200) is fitted and mounted at the first through hole (111); and the circumferential outer wall of the insulating portion (120) is provided with an annular flange (121); an annular mounting groove (122) configured to accommodate a top end (11) of a battery casing (10) is formed between the annular flange (121) and the circumferential outer wall of the insulating portion (120); and the circumferential inner wall of the battery casing (10) can be connected to the circumferential outer wall of the insulating portion (120) in a sealed manner.

Description

Cap assembly and individual battery

[0001] This application claims priority to Chinese Patent Application No. 202423184204.3, filed with the Chinese Patent Office on December 23, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of battery technology, such as a cap assembly and a single battery cell. Background Technology

[0003] The cap assembly of a cylindrical lithium-ion secondary battery generally includes a sealing sleeve, a top cover, an explosion-proof sheet, an orifice plate, and an insulating gasket disposed between the explosion-proof sheet and the orifice plate. A first pressure relief hole for pressure relief is also provided on the orifice plate.

[0004] In related technologies, as shown in Figure 1, after the battery cap assembly is sealed to the battery casing, the top part 11 of the battery casing 10 is not nickel-plated for protection and directly abuts against the outer wall of the sealing sleeve 100'. It is exposed to air for extended periods and is easily corroded by oxygen in the air under high temperature and humidity conditions. Rust easily forms at the port of the top part, resulting in poor product appearance, affecting customer experience, and even posing a risk of battery leakage. Currently, to protect the top part 11, the production process currently uses coating, brushing, or spraying of rust-preventive oil. However, this causes oil pollution, making battery cleaning and equipment maintenance inconvenient. Furthermore, most of the rust-preventive oils currently used for the top part 11 are volatile, which easily evaporates at high temperatures, failing to provide ideal protection for the port of the battery casing 10. Summary of the Invention

[0005] This application provides a cap assembly that improves the assembly effect between the battery casing and the cap assembly, enhances sealing performance, and protects the top of the battery casing, thus providing stronger safety.

[0006] The following technical solution is adopted in this application:

[0007] This application provides a cap assembly, including a sealing sleeve and a top cover. The sealing sleeve includes a support portion and an insulating portion. The insulating portion surrounds the circumferential edge of the support portion. The support portion is provided with a first through hole, and the top cover is fitted into the first through hole. The circumferential outer wall of the insulating portion is provided with an annular flange. An mounting annular groove is formed between the annular flange and the circumferential outer wall of the insulating portion to accommodate the top end of a battery housing. The circumferential inner wall of the battery housing can be sealed to the circumferential outer wall of the insulating portion.

[0008] In some implementations, the insulating portion includes a bent section, and the cap assembly is grooved and fixed to the battery housing so that the bent section can be attached to the top wall of the top cover, and the battery housing can form a crimped portion on the top cover.

[0009] In some implementations, the position where the crimping part covers the mounting annular groove is the sealing part, the length of the sealing part is L1, the length of the crimping part is L2, and L1≤L2.

[0010] In some implementations, the depth of the mounting annular groove is h, where h ≤ L2.

[0011] In some implementations, 0.3mm ≤ h ≤ 0.95mm.

[0012] In some implementations, the width of the mounting groove is b, and the wall thickness of the battery casing is B, where b > B.

[0013] In some implementations, a sealant layer is provided on the circumferential inner wall of the mounting groove, and the sealant layer can be attached to the circumferential outer wall of the battery casing.

[0014] In some implementations, the thickness of the sealant layer is c, where bc ≤ B.

[0015] In some implementations, the cap assembly also includes a blast-proof plate, an orifice plate, and an insulating gasket, with the insulating gasket sandwiched between the blast-proof plate and the orifice plate, the orifice plate abutting against the support portion, and the blast-proof plate abutting against the bottom wall of the top cover.

[0016] In some implementations, the insulating part can be bent and attached to the top cover, and the height of the top wall of the annular flange after bending is not higher than the height of the topmost part of the top cover.

[0017] This application also provides a single battery cell, which includes a battery casing and a cap assembly as provided in any of the embodiments, wherein the top end of the battery casing is fitted into a mounting ring groove.

[0018] Beneficial effects:

[0019] The cap assembly in this application features a top cover within a sealing sleeve. After the cap assembly is installed on the battery casing, the top of the battery casing can be inserted into an mounting groove on the outer peripheral wall of the insulating part of the sealing sleeve. This mounting groove is formed by an annular flange surrounding the circumferential outer wall of the insulating part, completely covering the top of the battery casing and preventing it from contacting external air, thus avoiding corrosion from high-temperature and humid air. Furthermore, the mounting groove guides and positions the battery casing and cap assembly during installation, improving production efficiency. Simultaneously, the mounting groove forms multiple seals with the battery casing, enhancing the sealing effect, preventing electrolyte leakage, and improving the safety of the individual battery cell. This cap assembly improves the assembly effect between the battery casing and the cap assembly, enhances sealing performance, and provides protection for the top of the battery casing, resulting in stronger safety. Attached Figure Description

[0020] Figure 1 is a longitudinal cross-sectional view of a portion of the structure after the cap assembly is fixed to the battery housing;

[0021] Figure 2 is a longitudinal cross-sectional view of the cap assembly provided in the specific embodiment of this application after it is installed in the battery casing;

[0022] Figure 3 is a longitudinal cross-sectional view of the cap assembly provided in a specific embodiment of this application;

[0023] Figure 4 is a longitudinal cross-sectional view of a portion of the structure of the cap assembly after it is fixed to the battery casing according to a specific embodiment of this application.

[0024] In the picture:

[0025] 10. Battery casing; 11. Top end; 12. Press-fit part;

[0026] 100. Sealing sleeve; 110. Support part; 111. First through hole; 120. Insulating part; 121. Annular flange; 122. Mounting ring groove; 123. Sealing layer; 124. Bending section;

[0027] 200. Top cover; 310. Explosion-proof sheet; 320. Perforated plate; 330. Insulating gasket. Detailed Implementation

[0028] The present application will now be described in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the application and not intended to limit its scope. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present application, not the entire structure.

[0029] In the description of this application, unless otherwise expressly specified and limited, the terms "connected," "linked," and "fixed" 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. Those skilled in the art can understand the specific meaning of the terms in this application based on the specific circumstances.

[0030] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0031] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0032] In related technologies, as shown in Figure 1, after the battery cap assembly is sealed to the battery casing, the top part 11 of the battery casing 10 is not nickel-plated for protection and directly abuts against the outer wall of the sealing sleeve 100'. It is exposed to air for extended periods and is easily corroded by oxygen in the air under high temperature and humidity conditions. Rust easily forms at the port of the top part 11, resulting in poor product appearance, affecting customer experience, and even posing a risk of battery leakage. Furthermore, applying anti-rust oil is not ideal for protecting the port of the top part 11. Therefore, this embodiment first provides a cap assembly. The specific structure of the cap assembly in this embodiment is described below with reference to Figures 2-4.

[0033] As shown in Figures 2 and 3, the cap assembly includes a sealing sleeve 100 and a top cover 200. The sealing sleeve 100 includes a support portion 110 and an insulating portion 120. The insulating portion 120 surrounds the circumferential edge of the support portion 110. The support portion 110 is provided with a first through hole 111, and the top cover 200 is fitted into the first through hole 111. The circumferential outer wall of the insulating portion 120 is provided with an annular flange 121. An mounting annular groove 122 for accommodating the top end portion 11 of the battery housing 10 is formed between the annular flange 121 and the circumferential outer wall of the insulating portion 120. The circumferential inner wall of the battery housing 10 can be sealed to the circumferential outer wall of the insulating portion 120.

[0034] In this embodiment, the cap assembly has a top cover 200 inside the sealing sleeve 100. After the cap assembly is installed on the battery housing 10, the top end 11 of the battery housing 10 can be inserted into the mounting annular groove 122 on the outer peripheral wall of the insulating part 120 of the sealing sleeve 100. The mounting annular groove 122 is formed by an annular flange 121 surrounding the circumferential outer wall of the insulating part 120, which can completely cover the top end 11 of the battery housing 10, preventing the top end 11 from contacting the outside air, thereby avoiding corrosion of the top end 11 by high temperature and humid air. Furthermore, the mounting annular groove 122 can guide and position the installation of the battery housing 10 and the cap assembly, improving production efficiency. Simultaneously, the mounting annular groove 122 can form multiple seals with the battery housing 10, improving the sealing effect, preventing electrolyte leakage, and improving the safety of the individual battery. This cap assembly improves the assembly effect between the battery housing 10 and the cap assembly, enhances sealing performance, and protects the top end 11 of the battery housing 10, resulting in stronger safety.

[0035] As shown in Figures 3 and 4, the insulating portion 120 includes a bent section 124. The cap assembly is fixed to the battery housing 10 after being grooved, so that the bent section 124 can be attached to the top wall of the top cover 200, and the battery housing 10 can form a pressing portion 12 on the top cover 200. The cap assembly is fixed to the battery housing 10 using a grooving process, so that the top end 11 of the battery housing 10 forms a pressing portion 12. At the same time, the insulating portion 120 forms a bent section 124, so that the inner wall of the bent section 124 abuts against the top wall of the top cover 200, thereby fixing the battery housing 10 and the sealing sleeve 100 to the top cover 200. This also reduces the vertical height of the cap assembly, thereby reducing the vertical height of the individual battery, reducing the volume occupied by the individual battery, and increasing the energy density of the individual battery.

[0036] For example, as shown in FIG4, a bent section 124 of a sealing sleeve 100 is sandwiched between the crimping part 12 and the top cover 200, thereby fixing the sealing sleeve 100 to the battery housing 10. In this embodiment, the crimping part 12 is a section of the top part 11 of the battery housing 10 that is bent and parallel to the horizontal direction, which will not be described in detail here.

[0037] The area where the crimping part 12 covers the mounting annular groove 122 is a sealing part. The length of the sealing part is L1, and the length of the crimping part 12 is L2, where L1 ≤ L2. This arrangement prevents the end of the annular flange 121 from protruding from the crimping part 12, avoids the annular flange 121 from occupying too large a horizontal dimension after the grooving is completed, and prevents the annular flange 121 from rolling up after being bumped, thus improving the stability of the connection.

[0038] In this embodiment, the depth of the mounting annular groove 122 is h, where h ≤ L2. The depth of the mounting annular groove 122 is the vertical dimension of the mounting annular groove 122 in Figure 3. Since its depth is not greater than the length of the pressing part 12 of the battery housing 10, it can prevent the end of the annular flange 121 from protruding from the pressing part 12 when the battery housing 10 is fully inserted into the mounting annular groove 122. This will not be described in detail here.

[0039] Optionally, 0.3mm ≤ h ≤ 0.95mm. The value of L2 is related to the battery model. The L2 range for 18-series cylindrical batteries is 0.95mm to 1.3mm, while the L2 value for 21-series cylindrical batteries is larger than that for 18-series batteries. Therefore, in order to be compatible with 18-series and 21-series battery models, the value of h is in the range of 0.3mm to 0.95mm. The value of h can be specifically selected according to the model of the individual battery, and its range can also be changed according to requirements, which will not be elaborated here.

[0040] Please continue referring to Figures 3 and 4. The width of the mounting groove 122 is b, and the wall thickness of the battery casing 10 is B, where b > B. In this embodiment, the wall thickness of the battery casing 10 is 0.25 mm, and the width of the mounting groove 122 is 0.3 ± 0.05 mm. This ensures that the top end 11 of the battery casing 10 is completely covered by the mounting groove 122, forming an interference fit, improving sealing performance, and thus enhancing the protection of the top end 11.

[0041] A sealant layer 123 is provided on the circumferential inner wall of the mounting groove 122, and the sealant layer 123 can be attached to the circumferential outer wall of the battery casing 10. The sealant layer 123 can ensure a tight fit between the mounting groove 122 and the top end 11 of the battery casing 10, and the sealing effect of the sealant prevents moisture and air from seeping in from the gaps, thus improving the sealing effect.

[0042] Optionally, the thickness of the sealant layer 123 is c, where bc ≤ B. In this embodiment, the sealant layer 123 occupies a portion of the width of the mounting ring groove 122, thereby forming an interference fit between the space formed by the sealant layer 123 and the mounting ring groove 122 and the top end 11 of the battery housing 10, improving the sealing effect of the sealant layer and enhancing the protection capability of the top end 11 of the battery housing 10.

[0043] The sum of the thickness of the annular flange 121 and the thickness of the sealant layer 123 is not less than 0.2 mm. This is because the thickness of the head pad of the original label-type cylindrical battery is 0.2 mm, which avoids affecting the installation of the single battery in this embodiment. For example, the thickness of the annular flange 121 is 0.15 mm and the thickness of the sealant layer 123 is 0.05 mm, which will not be described in detail here.

[0044] After the insulating part 120 is bent, it can be attached to the top cover 200. After bending, the height of the top wall of the annular flange 121 is not higher than the height of the top of the top cover 200, so as not to affect the installation of the single battery using the cap assembly, and not to hinder the electrical connection between the top cover 200 of the cap assembly and external devices.

[0045] Optionally, the cap assembly further includes an explosion-proof plate 310, a perforated plate 320, and an insulating gasket 330. The insulating gasket 330 is sandwiched between the explosion-proof plate 310 and the perforated plate 320. The perforated plate 320 abuts against the support portion 110, and the explosion-proof plate 310 abuts against the bottom wall of the top cover 200. In use, the high-pressure gas inside the battery can be released through the pressure relief hole on the perforated plate 320, causing the explosion-proof plate 310 above the perforated plate 320 to rupture, thus releasing gas and pressure. Furthermore, the rupture of the explosion-proof plate 310 disconnects the connection between the explosion-proof plate 310 and the perforated plate 320. Simultaneously, the insulating gasket 330 blocks the connection between the explosion-proof plate 310 and the perforated plate 320, achieving a circuit break in the cap assembly. This timely disconnection of the circuit during battery thermal runaway improves safety.

[0046] This application also provides a single-cell battery, which includes a battery casing 10 and a cap assembly as provided in any embodiment. The top end 11 of the battery casing 10 is fitted into a mounting annular groove 122. Taking a cylindrical lithium-ion secondary battery as an example, the battery includes a battery casing 10, a cap assembly, a positive electrode, a negative electrode, a separator, and an electrolyte. The battery casing 10 can be made of nickel-plated steel plate material and has a hollow cylindrical structure with an open top. The cap assembly is connected to the top end 11 of the battery casing 10 and seals the top end 11. The battery casing 10 and the cap assembly enclose the internal cavity of the battery. The separator can be made of polyethylene film material and is used to separate the positive electrode material and the negative electrode material. The positive electrode material, the negative electrode material, and the separator are spirally wound in the internal cavity of the battery.

[0047] The positive electrode can be electrically connected to the cap assembly via the positive electrode busbar, and the negative electrode can be electrically connected to the outer casing via the negative electrode busbar; alternatively, the positive electrode can be electrically connected to the outer casing via the positive electrode busbar, and the negative electrode can be electrically connected to the cap assembly via the negative electrode busbar.

[0048] This embodiment also provides an electrical device, which includes the battery provided in this application. The battery can be used in a combination for portable electrical devices. A battery cavity is provided inside the portable electrical device, which can accommodate one or more batteries, matched according to the power capacity required by the electrical device. The electrical device can be any device in the related art that requires a lithium-ion battery to provide power.

[0049] Electrical devices can also be powered by battery packs. Multiple batteries within a battery pack can be connected in series, in parallel, or a combination of both, to provide the appropriate capacity and power for the device. Applicable devices include mobile phones, portable devices, laptops, electric bicycles, electric cars, electric boats, electric toys, and power tools, which will not be elaborated further here.

Claims

1. A cap assembly, comprising a sealing sleeve (100) and a top cover (200), wherein the sealing sleeve (100) comprises a support portion (110) and an insulating portion (120), the insulating portion (120) surrounding the circumferential edge of the support portion (110), the support portion (110) being provided with a first through hole (111), and the top cover (200) being fitted into the first through hole (111); the circumferential outer wall of the insulating portion (120) is provided with an annular flange (121), and an mounting annular groove (122) is formed between the annular flange (121) and the circumferential outer wall of the insulating portion (120) to accommodate the top end portion (11) of a battery housing (10), and the circumferential inner wall of the battery housing (10) is capable of being sealed to the circumferential outer wall of the insulating portion (120).

2. The cap assembly of claim 1, wherein, The insulating part (120) includes a bent section (124), and the cap assembly is fixed to the battery housing (10) after being grooved, so that the bent section (124) can be attached to the top wall of the top cover (200), and the battery housing (10) can form a crimped part (12) on the top cover (200).

3. The cap assembly of claim 2, wherein, The position of the crimping part (12) covering the mounting ring groove (122) is a sealing part. The length of the sealing part is L1, and the length of the crimping part (12) is L2, where L1≤L2.

4. The cap assembly of claim 3, wherein, The depth of the mounting annular groove (122) is h, where h ≤ L2.

5. The cap assembly of claim 4, wherein, 0.3mm≤h≤0.95mm.

6. The cap assembly of claim 5, wherein, The width of the mounting groove (122) is b, and the wall thickness of the battery casing (10) is B, where b > B.

7. The cap assembly of claim 6, wherein, The inner circumferential wall of the mounting groove (122) is provided with a sealant layer (123), which can be attached to the outer circumferential wall of the battery casing (10).

8. The cap assembly of claim 7, wherein, The thickness of the sealant layer (123) is c, where bc ≤ B.

9. The cap assembly according to any one of claims 1-8 further includes an explosion-proof plate (310), a perforated plate (320), and an insulating gasket (330), the insulating gasket (330) being sandwiched between the explosion-proof plate (310) and the perforated plate (320), the perforated plate (320) abutting against the support portion (110), and the explosion-proof plate (310) abutting against the bottom wall of the top cover (200).

10. The cap assembly of any one of claims 1-8, wherein, After the insulation part (120) is bent, it can be attached to the top cover (200). After bending, the height of the top wall of the annular flange (121) is not higher than the height of the topmost part of the top cover (200).

11. A single battery cell, comprising a battery housing (10) and a cap assembly as claimed in any one of claims 1-10, wherein the top end (11) of the battery housing (10) is fitted into the mounting annular groove (122).

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