Safety cap structure for lithium battery

Abstract

The utility model discloses a safety cap structure for a lithium battery, which comprises a sealing ring provided with a mounting inner cavity; a top cover; a PTC sheet; the anti-explosion piece is provided with a first step, and the back face of the first step is a right angle; the pore plate gasket is provided with a second step, the front face of the second step is a right angle, and the back face of the first step abuts against the front face of the second step; an orifice plate; the top cover, the PTC piece, the anti-explosion piece, the pore plate gasket and the pore plate are sequentially stacked in the mounting inner cavity from outside to inside in the axial direction of the sealing ring. According to the utility model, the PTC sheet is arranged to realize power-off protection; the explosion-proof sheet is provided with a first step, the back surface of the first step is a right angle, the pore plate gasket is provided with a second step, the front surface of the second step is a right angle, and the back surface of the first step is propped against the front surface of the second step, so that the explosion-proof sheet and the pore plate gasket are connected more compactly, and the thickness of the whole structure of the utility model in the axial direction can be reduced; the purpose of improving the capacity of the battery cell is achieved.

Description

Technical Field

[0001] This utility model relates to the field of lithium batteries, and in particular to a safety cap structure for lithium batteries. Background Technology

[0002] With the rapid development of the new energy industry, new energy batteries are almost ubiquitous in people's lives. When a battery is being charged for a long time, if there is no effective power-off protection, the battery temperature will continue to accumulate. When the temperature rises to a certain level, it will cause thermal runaway, resulting in the cell catching fire and exploding. For lithium batteries, especially cylindrical batteries, power-off protection is mainly achieved by the cap structure.

[0003] Chinese utility model patent CN205692874U discloses a safety cap with an insulating washer between an explosion-proof sheet and a perforated plate. The insulating washer includes an outer connecting part, an inner connecting part, and a clamping part arranged in a Z-shape. The cross-section of the part where the explosion-proof sheet contacts the insulating washer forms two symmetrical first Z-shapes, with the middle section of the first Z-shape inclined towards the center. The inner connecting part and the clamping part of the insulating washer form a right angle of contact, and the first lower sharp corner of the first Z-shape abuts against the right angle of contact of the insulating washer. The cross-section of the part where the perforated plate contacts the insulating washer forms two symmetrical second Z-shapes, with the middle section of the second Z-shape inclined towards the sealing ring. The inner connecting part and the clamping part of the insulating washer form a right angle of contact, and the right angle of contact is located at the second lower sharp corner of the second Z-shape. In this technical solution, the explosion-proof sheet is designed in a "Z" shape. The "Z" shape of the explosion-proof sheet cannot fit the right angle design of the insulating washer, which requires the overall structure of the safety cap to be larger, thereby reducing the space inside the battery cell that can accommodate the core. Utility Model Content

[0004] To overcome at least one of the defects described in the prior art, this utility model provides a safety cap structure for lithium batteries. This utility model incorporates a PTC chip for power-off protection. Furthermore, the explosion-proof sheet in this utility model has a first step with a right angle on its back side, and the perforated plate gasket in this utility model has a second step with a right angle on its front side. The back side of the first step abuts against the front side of the second step, making the connection between the explosion-proof sheet and the perforated plate gasket more compact. This reduces the overall axial thickness of the utility model structure, increases the internal space height for accommodating the winding core, and ultimately increases the battery cell capacity.

[0005] The technical solution adopted by this utility model to solve its problem is:

[0006] A safety cap structure for lithium batteries, comprising:

[0007] The sealing ring has an inner cavity for installation;

[0008] Top cover;

[0009] PTC film;

[0010] The explosion-proof sheet has a first step, and the back of the first step is a right angle;

[0011] The orifice plate gasket has a second step, the front of which is a right angle, and the back of the first step abuts against the front of the second step.

[0012] Orifice plate;

[0013] The top cover, PTC sheet, explosion-proof sheet, orifice plate gasket, and orifice plate are stacked sequentially from the outside to the inside along the axial direction of the sealing ring inside the mounting cavity.

[0014] In a preferred embodiment, the first step is a right-angled step, and the front of the first step is also a right angle;

[0015] The second step is a partially right-angled step, and the back of the second step is at an angle.

[0016] In a preferred embodiment, the explosion-proof sheet also has a third step;

[0017] The explosion-proof sheet includes a first connecting part, a second connecting part, and a third connecting part. The first connecting part, the second connecting part, and the third connecting part are sequentially connected along the radial direction of the explosion-proof sheet. A first step is formed between the first connecting part and the second connecting part, and a third step is formed between the second connecting part and the third connecting part.

[0018] In a preferred embodiment, the orifice plate gasket includes a first insulating portion, a second insulating portion, and a third insulating portion, which are sequentially connected along the radial direction of the orifice plate gasket.

[0019] The first insulating part covers the edge of the orifice plate along the axial direction of the orifice plate gasket, the front of the second insulating part abuts against the back of the first connecting part, the back of the third insulating part abuts against the front of the second connecting part, and a second step is formed between the second insulating part and the third insulating part.

[0020] In a preferred embodiment, the sidewall of the sealing ring is provided with a first protrusion, the bottomwall of the sealing ring is provided with a second protrusion, and the top cover, PTC sheet and explosion-proof sheet are installed between the first protrusion and the second protrusion.

[0021] In a preferred embodiment, the top cover, the PTC sheet, and the explosion-proof sheet are interference-fitted between the first protrusion and the second protrusion;

[0022] The back of the first protrusion abuts against the front of the top cover;

[0023] The front of the second protrusion abuts against the back of the explosion-proof sheet.

[0024] In a preferred embodiment, a recess is formed between the second protrusion and the sidewall of the sealing ring, the recess being used to accommodate adhesive, which is then bonded to the back of the explosion-proof sheet.

[0025] In a preferred embodiment, the thickness of the PTC sheet is equal to the thickness of the explosion-proof sheet.

[0026] In a preferred embodiment, a pressure relief through hole is provided in the central region of the PTC sheet, and the PTC sheet has a ring-shaped structure.

[0027] In a preferred embodiment, the top cover, the perforated gasket, and the perforated plate are all provided with pressure relief holes.

[0028] In summary, this utility model has the following technical effects:

[0029] This invention features a PTC chip for power failure protection. Furthermore, the explosion-proof chip has a first step with a right angle on the back, and the perforated plate gasket has a second step with a right angle on the front. The back of the first step abuts against the front of the second step, making the connection between the explosion-proof chip and the perforated plate gasket more compact. This reduces the overall axial thickness of the invention, increases the internal space for accommodating the winding core, and ultimately increases the battery cell capacity. Attached Figure Description

[0030] Figure 1 This is a cross-sectional schematic diagram of an embodiment of the present utility model;

[0031] Figure 2 This is a cross-sectional schematic diagram of the explosion-proof sheet and the perforated plate gasket in an embodiment of this utility model;

[0032] Figure 3 This is a cross-sectional schematic diagram of the sealing ring according to an embodiment of the present invention;

[0033] Figure 4 This is an embodiment of the present utility model. Figure 1 A top-down view;

[0034] Figure 5 This is an embodiment of the present utility model. Figure 1 A diagram showing the view from below.

[0035] The meanings of the reference numerals in the attached figures are as follows:

[0036] 10. Sealing ring; 101. Mounting cavity; 102. First protrusion; 103. Second protrusion; 104. Recess; 20. Top cover; 30. PTC sheet; 40. Explosion-proof sheet; 401. First step; 402. Third step; 403. First connecting part; 404. Second connecting part; 405. Third connecting part; 50. Orifice plate gasket; 501. Second step; 502. First insulating part; 503. Second insulating part; 504. Third insulating part; 60. Orifice plate; 70. Pressure relief through hole. Detailed Implementation

[0037] To better understand and implement this invention, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings.

[0038] In the description of this utility model, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, 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 utility model.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0040] See Figures 1-5 This utility model discloses a safety cap structure for lithium batteries, comprising: a sealing ring 10 having an installation cavity 101; a top cover 20; a PTC sheet 30; an explosion-proof sheet 40 having a first step 401 with the back of the first step 401 being a right angle; a perforated plate gasket 50 having a second step 501 with the front of the second step 501 being a right angle, the back of the first step 401 abutting against the front of the second step 501; and a perforated plate 60. The top cover 20, PTC sheet 30, explosion-proof sheet 40, perforated plate gasket 50, and perforated plate 60 are sequentially stacked from the outside to the inside along the axial direction of the sealing ring 10 inside the installation cavity 101.

[0041] This invention features a PTC chip 30 for power failure protection; and the explosion-proof chip 40 has a first step 401 with a right angle on the back. The perforated plate gasket 50 has a second step 501 with a right angle on the front. The back of the first step 401 abuts against the front of the second step 501, making the connection between the explosion-proof chip 40 and the perforated plate gasket 50 more compact. This reduces the overall thickness of the invention in the axial direction, increases the internal space height for accommodating the winding core, and achieves the goal of increasing the capacity of the battery cell.

[0042] In this embodiment of the utility model, the first step 401 is a right-angled step, and the front of the first step 401 is also a right angle; the second step 501 is a partially right-angled step, and the back of the second step 501 is an oblique angle.

[0043] It should be noted that the aforementioned right-angled steps refer to steps with an included angle of 90°.

[0044] In this embodiment of the invention, the explosion-proof sheet 40 further has a third step 402; the explosion-proof sheet 40 includes a first connecting part 403, a second connecting part 404 and a third connecting part 405, the first connecting part 403, the second connecting part 404 and the third connecting part 405 are sequentially connected along the radial direction of the explosion-proof sheet 40, a first step 401 is formed between the first connecting part 403 and the second connecting part 404, and a third step 402 is formed between the second connecting part 404 and the third connecting part 405.

[0045] Specifically, the explosion-proof sheet 40 is a one-piece molded structure, that is, the first connecting part 403, the second connecting part 404, the third connecting part 405, the first step 401 and the third step 402 are integrally molded.

[0046] More specifically, both the first step 401 and the third step 402 extend away from the top cover 20, so that the explosion-proof sheet 40 forms a recess away from the top cover 20.

[0047] In this embodiment of the present invention, the perforated plate gasket 50 includes a first insulating part 502, a second insulating part 503, and a third insulating part 504. The first insulating part 502, the second insulating part 503, and the third insulating part 504 are sequentially connected along the radial direction of the perforated plate gasket 50. The first insulating part 502 covers the edge of the perforated plate 60 along the axial direction of the perforated plate gasket 50. The front side of the second insulating part 503 abuts against the back side of the first connecting part 403. The back side of the third insulating part 504 abuts against the front side of the second connecting part 404. A second step 501 is formed between the second insulating part 503 and the third insulating part 504.

[0048] Specifically, the perforated plate gasket 50 is an integrally formed structure, that is, the first insulating part 502, the second insulating part 503, the third insulating part 504 and the second step 501 are integrally formed.

[0049] More specifically, in order to achieve insulation, the perforated plate gasket 50 is made of insulating material, such as rubber, silicone, etc. Of course, other existing insulating materials can also be used without limitation; the explosion-proof plate 40 and the perforated plate 60 are both metal parts.

[0050] Since the explosion-proof plate 40 includes a first connecting part 403, a second connecting part 404, and a third connecting part 405, the orifice plate gasket 50 is widened by providing a third insulating part 504. The back side of the third insulating part 504 abuts against the front side of the second connecting part 404, increasing the insulation area between the explosion-proof plate 40 and the orifice plate 60 in the radial direction. Furthermore, the orifice plate gasket 50 insulates the explosion-proof plate 40 and the orifice plate 60 in the axial direction through the first insulating part 502. The above structure ensures the insulation effect between the explosion-proof plate 40 and the orifice plate 60.

[0051] It should be noted that the orifice plate gasket 50 is set so as not to affect the electrical connection between the central area of ​​the orifice plate gasket 50 and the orifice plate 60.

[0052] In this embodiment of the present invention, the side wall of the sealing ring 10 is provided with a first protrusion 102, the bottom wall of the sealing ring 10 is provided with a second protrusion 103, and the top cover 20, the PTC sheet 30 and the explosion-proof sheet 40 are installed between the first protrusion 102 and the second protrusion 103.

[0053] In this embodiment of the utility model, the top cover 20, the PTC sheet 30 and the explosion-proof sheet 40 are interference-fitted between the first protrusion 102 and the second protrusion 103; the back side of the first protrusion 102 abuts against the front side of the top cover 20; and the front side of the second protrusion 103 abuts against the back side of the explosion-proof sheet 40.

[0054] It should be noted that the PTC sheet 30 has a specification of 0.1mΩ-16mΩ, which can meet the different resistance requirements of the battery cell. To ensure the tightness of the contact surface of the PTC sheet 30, it is achieved through the first protrusion 102 and the second protrusion 103 of the sealing ring 10 structure. The top cover 20, the PTC sheet 30 and the explosion-proof sheet 40 are interference-fitted between the first protrusion 102 and the second protrusion 103, which can ensure good contact between the mating surfaces of the top cover 20, the PTC sheet 30 and the explosion-proof sheet 40, and achieve the internal resistance of the safety cap structure for lithium batteries fluctuating within ±2mΩ.

[0055] In this embodiment of the present invention, a recess 104 is formed between the second protrusion 103 and the side wall of the sealing ring 10. The recess 104 is used to accommodate adhesive, which is used to bond the back of the explosion-proof sheet 40.

[0056] Specifically, existing battery adhesives can be used for bonding.

[0057] Preferably, both the first protrusion 102 and the second protrusion 103 are annular structures.

[0058] More preferably, both the first protrusion 102 and the second protrusion 103 are annular rib structures.

[0059] Because the top cover 20, PTC sheet 30, and explosion-proof sheet 40 are interference-fitted between the first protrusion 102 and the second protrusion 103, the first protrusion 102 and the second protrusion 103 limit the explosion-proof sheet 40 in the axial direction, thereby preventing the explosion-proof sheet 40 from shaking along the axial direction of the sealing ring 10; the back of the explosion-proof sheet 40 is fixed with adhesive, and the explosion-proof sheet 40 is limited in the radial direction, thereby preventing the explosion-proof sheet 40 from shaking along the radial direction of the sealing ring 10; in this way, the explosion-proof sheet 40 is limited in both its axial and radial directions, improving its installation stability.

[0060] In this embodiment of the utility model, in order to ensure that the neck height of the battery cell is consistent, the thickness of the PTC sheet 30 is equal to the thickness of the explosion-proof sheet 40; the thickness specification of the PTC sheet 30 is generally 0.30±0.03mm.

[0061] In this embodiment of the utility model, in order not to affect the pressure relief of the safety cap structure for the lithium battery, a pressure relief through hole 70 is provided in the central area of ​​the PTC sheet 30, and the PTC sheet 30 has a ring structure.

[0062] Preferably, the top cover 20, the explosion-proof sheet 40, the perforated plate gasket 50, and the perforated plate 60 are all circular sheet structures.

[0063] In this embodiment of the invention, pressure relief holes 70 are provided on the top cover 20, the perforated plate gasket 50, and the perforated plate 60, thereby facilitating the release of internal pressure in the battery.

[0064] The technical means disclosed in this utility model are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of this utility model, and these improvements and modifications are also considered within the scope of protection of this utility model.

Claims

1. A safety cap structure for lithium batteries, characterized in that, include: A sealing ring having an mounting cavity; Top cover; PTC film; An explosion-proof sheet, wherein the explosion-proof sheet has a first step, and the back of the first step is a right angle; The perforated plate gasket has a second step, the front of which is a right angle, and the back of the first step abuts against the front of the second step. Orifice plate; The top cover, the PTC sheet, the explosion-proof sheet, the perforated plate gasket, and the perforated plate are stacked sequentially from the outside to the inside along the axial direction of the sealing ring inside the mounting cavity.

2. The safety cap structure for lithium batteries according to claim 1, characterized in that: The first step is a right-angled step, and the front of the first step is also a right angle; The second step is a partially right-angled step, and the back of the second step is at an angle.

3. The safety cap structure for lithium batteries according to claim 2, characterized in that: The explosion-proof sheet also has a third step; The explosion-proof sheet includes a first connecting part, a second connecting part, and a third connecting part. The first connecting part, the second connecting part, and the third connecting part are sequentially connected along the radial direction of the explosion-proof sheet. A first step is formed between the first connecting part and the second connecting part, and a third step is formed between the second connecting part and the third connecting part.

4. The safety cap structure for lithium batteries according to claim 3, characterized in that: The perforated plate gasket includes a first insulating part, a second insulating part, and a third insulating part, which are sequentially connected along the radial direction of the perforated plate gasket. The first insulating portion covers the edge of the perforated plate along the axial direction of the perforated plate gasket, the front of the second insulating portion abuts against the back of the first connecting portion, the back of the third insulating portion abuts against the front of the second connecting portion, and a second step is formed between the second insulating portion and the third insulating portion.

5. The safety cap structure for lithium batteries according to claim 1, characterized in that: The sealing ring has a first protrusion on its side wall and a second protrusion on its bottom wall. The top cover, the PTC sheet, and the explosion-proof sheet are installed between the first protrusion and the second protrusion.

6. The safety cap structure for lithium batteries according to claim 5, characterized in that: The top cover, the PTC sheet, and the explosion-proof sheet are interference-fitted between the first protrusion and the second protrusion; The back side of the first protrusion abuts against the front side of the top cover; The front of the second protrusion abuts against the back of the explosion-proof sheet.

7. The safety cap structure for lithium batteries according to claim 5, characterized in that: A recess is formed between the second protrusion and the sidewall of the sealing ring, the recess being used to accommodate adhesive, which is then bonded to the back of the explosion-proof sheet.

8. The safety cap structure for lithium batteries according to any one of claims 1-7, characterized in that: The thickness of the PTC sheet is equal to the thickness of the explosion-proof sheet.

9. The safety cap structure for lithium batteries according to any one of claims 1-7, characterized in that: The PTC sheet has a pressure relief hole in its central area, and the PTC sheet has a ring-shaped structure.

10. The safety cap structure for lithium batteries according to any one of claims 2-4, characterized in that: The top cover, the perforated plate gasket, and the perforated plate are all provided with pressure relief holes.

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