Sealing nail with explosion-proof and sealing functions and secondary battery top cover

Abstract

The utility model discloses a sealing nail with explosion-proof and sealing functions and a secondary battery top cover, the sealing nail comprises a cover plate and a sealing aluminum sheet, the cover plate is a flat plate type aluminum sheet structure with smooth upper and lower surfaces, two sides of the cover plate are symmetrically provided with an anode mounting hole and a cathode mounting hole, and a liquid injection hole is arranged between the anode mounting hole and the cathode mounting hole. The cover plate can be welded at the upper end of the square battery aluminum shell to seal the battery aluminum shell, and electrolyte can be injected into the battery aluminum shell through the liquid injection hole; the sealing aluminum sheet is round, the diameter of the sealing aluminum sheet is larger than that of the liquid injection hole, the sealing aluminum sheet can be welded to the liquid injection hole to seal the liquid injection hole, an anti-explosion structure is arranged in the middle of the sealing aluminum sheet and is in a round hole shape, and when the pressure in the sealed battery aluminum shell exceeds a safety value, air pressure can break through the anti-explosion structure on the sealing aluminum sheet, so that the liquid injection hole is sealed. The sealing aluminum sheet is annularly broken from the middle part and is divided into two parts of structures including an inner side circular sheet and an outer side circular sheet; according to the utility model, the cost of the cover plate is reduced, and the yield of the battery cell manufacturing process is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of new energy battery housing seals, and particularly relates to a sealing nail and a secondary battery top cover with both explosion-proof and sealing functions. Background Art

[0002] New energy power batteries refer to batteries with renewable energy as the main power supply. Common power batteries mainly include lithium batteries, lead-acid batteries, sodium-sulfur batteries, etc. Compared with traditional power batteries, new energy power batteries have the advantages of large capacity, high charge and discharge efficiency, long service life, and no lead pollution. When conventional lithium batteries and sodium batteries use hard carbon as the negative electrode, volume effects will occur during the insertion and extraction of electrode materials, and a large amount of gas will be generated during the manufacturing process and service life of the battery cells. For safety requirements, special explosion-proof valves are usually set on the packaging shell or cover of this type of square battery cell and cylindrical battery cell (such as the solutions disclosed in CN220672792U; CN116259920B; CN308617273S; CN201910749967.2; CN201811574829.7, etc.). Currently, the outer packaging structural parts of the battery cells are mainly top covers and aluminum shells. When packaging the battery cells, a sealing aluminum sheet (sealing aluminum nail) will be welded on the liquid injection port to seal the battery cell, and then secondary helium detection will be carried out. If a special explosion-proof valve needs to be installed, the explosion-proof valve will be welded on the top cover as a separate part, and corresponding explosion-proof valve holes need to be reserved on the top cover, and then the explosion-proof valve and the top cover will be connected together. The cost of the top cover is related to the cost of the explosion-proof valve and the yield of the laser welding process. Therefore, this has always been a pain point for the high cost of the top cover.

[0003] For batteries with systems such as dual-anion sodium ions that do not generate gas and have zero volume effect, although no gas is generated during their manufacturing process and service life and there is no risk of expansion, such batteries may still expand due to reasons such as aging, pinprick, and thermal failure, causing the internal air pressure of the battery cell to exceed the safety value. Therefore, a corresponding pressure relief and explosion-proof structure also needs to be set to ensure safety. However, due to cost and process considerations, the setting form of an independent explosion-proof valve is not an ideal explosion-proof structure. Summary of the Utility Model

[0004] In view of the above problems and technical requirements, the utility model provides a sealing nail and a secondary battery top cover with both explosion-proof and sealing functions, integrating the explosion-proof valve function and the sealing function, eliminating the need to set a separate explosion-proof valve and opening holes for installing the explosion-proof valve on the cover plate, reducing the number of parts and process steps of the cover plate, not only reducing the cost of the cover plate, but also improving the yield of the battery cell manufacturing process.

[0005] The technical solution of the present utility model is as follows: A sealing nail and a secondary battery top cover with both explosion-proof and sealing functions, including a cover plate and a sealing aluminum sheet. The cover plate is a flat aluminum sheet structure with smooth upper and lower surfaces. On both sides of the cover plate, a positive electrode mounting hole and a negative electrode mounting hole are symmetrically provided. A liquid injection hole is provided between the positive electrode mounting hole and the negative electrode mounting hole. The cover plate is rectangular, and circular chamfers are provided at the four corners of the cover plate. The cover plate can be welded to the upper end of the square battery aluminum shell to seal the battery aluminum shell, and electrolyte can be injected into the battery aluminum shell through the liquid injection hole; the sealing aluminum sheet is circular, the diameter of the sealing aluminum sheet is larger than the diameter of the liquid injection hole, the sealing aluminum sheet can be welded on the liquid injection hole to seal the liquid injection hole, and an explosion-proof structure is provided in the middle of the sealing aluminum sheet. The explosion-proof structure is a circular hole shape. When the pressure in the sealed battery aluminum shell exceeds the safety value, the air pressure can break through the explosion-proof structure on the sealing aluminum sheet, and the sealing aluminum sheet is annularly disconnected from the middle, being divided into two parts: an inner circular sheet and an outer circular ring sheet structure.

[0006] Further, the sealing aluminum sheet is an inverted frustum-shaped structure, and the thickness of the sealing aluminum sheet is 0.8 - 2.5 mm.

[0007] Further, a welding groove is provided on the upper surface of the sealing aluminum sheet near the edge. The depth of the welding groove is 0.5 - 1.2 mm, the width of the bottom of the welding groove is 0.2 - 1.5 mm, and a transition fillet is provided on the upper edge of the welding groove.

[0008] Further, a circular blasting blind hole is provided at the core of the bottom surface of the sealing aluminum sheet. The diameter range of the blasting blind hole is 10 - 20 mm, the depth of the blasting blind hole is 0.1 - 0.5 mm, and a fillet is provided at the bottom edge of the blasting blind hole.

[0009] Further, a circular blasting groove is provided on the bottom surface of the blasting blind hole. The thickness between the bottom of the blasting groove and the upper surface of the sealing aluminum sheet is 0.3 - 2.4 mm, and the diameter of the blasting groove is 8 - 15 mm.

[0010] Further, the cross-section of the blasting groove is conical, and a circle of explosion-proof scoring lines is provided at the bottom of the blasting groove. The depth of the explosion-proof scoring lines forming the blasting groove is 0.01 - 0.2 mm.

[0011] Further, when the sealing aluminum sheet is welded to the liquid injection hole, the liquid injection hole is directly opposite to the center of the blasting blind hole.

[0012] Advantages of the present utility model: 1) The present utility model uses a flat aluminum sheet with smooth upper and lower surfaces as the cover plate. Only the positive electrode mounting hole, negative electrode mounting hole, and liquid injection hole features need to be stamped on the cover plate. The explosion-proof valve and the sealing nail are combined into one, eliminating the welding process between the explosion-proof valve and the aluminum sheet, as well as the explosion-proof valve manufacturing process (stamping, cleaning, annealing, etc.) and the process of pasting the explosion-proof valve protective film. This makes the production of the entire cover plate more concise and efficient, improves the yield in the manufacturing process, and reduces the cost of components. 2) The sealing aluminum nail can not only be welded to the liquid injection hole to seal the battery cell, but also burst along the explosion-proof scoring line in a timely manner when the internal pressure of the battery is too high to relieve the internal pressure, ensuring the safety performance of the battery. The integrated manufacturing method eliminates the process of installing the explosion-proof valve separately, reduces the manufacturing cost of the battery cell seal, makes the packaging process of the battery cell more controllable, and has higher packaging efficiency. Brief Description of the Drawings

[0013] Figure 1 It is a structural diagram of the cover plate in the sealing nail of the top cover of the secondary battery of the present utility model;

[0014] Figure 2 It is a structural diagram of the upper surface of the sealing aluminum sheet in the sealing nail of the top cover of the secondary battery of the present utility model;

[0015] Figure 3 It is a sectional structural diagram of the sealing aluminum sheet in the sealing nail of the top cover of the secondary battery of the present utility model;

[0016] The marks in the figure are: cover plate 1, positive electrode mounting hole 11, negative electrode mounting hole 12, liquid injection hole 13, sealing aluminum sheet 2, welding groove 3, transition fillet 31, blasting blind hole 4, blasting round groove 41, explosion-proof scoring line 42. Detailed Embodiment

[0017] The following further describes the present utility model in conjunction with the drawings and embodiments.

[0018] As Figures 1-3 shown, the sealing nail of the top cover of the secondary battery with both explosion-proof and sealing functions of the present utility model includes a cover plate 1 and a sealing aluminum sheet 2. The cover plate 1 is a flat aluminum sheet structure with smooth upper and lower surfaces. On both sides of the cover plate 1, a positive electrode mounting hole 11 and a negative electrode mounting hole 12 are symmetrically arranged. A liquid injection hole 13 is arranged between the positive electrode mounting hole 11 and the negative electrode mounting hole 12. The cover plate 1 is rectangular, and circular chamfers are arranged at the four corners of the cover plate 1. The cover plate 1 can be welded to the upper end of the square battery aluminum shell to seal the battery aluminum shell, and electrolyte can be injected into the battery aluminum shell through the liquid injection hole 13.

[0019] The sealing aluminum sheet 2 is circular, and the diameter of the sealing aluminum sheet 2 is larger than that of the liquid injection hole 13. The sealing aluminum sheet 2 can be welded on the liquid injection hole 13 to seal the liquid injection hole 13. The sealing aluminum sheet 2 is an inverted frustum-shaped structure, and the thickness of the sealing aluminum sheet 2 is 0.8 - 2.5 mm. A welding groove 3 is provided around the edge of the upper surface of the sealing aluminum sheet 2. The depth of the welding groove 3 is 0.5 - 1.2 mm, the width of the bottom of the welding groove 3 is 0.2 - 1.5 mm, and a transition fillet 31 is provided at the upper edge of the welding groove 3.

[0020] An explosion-proof structure is provided in the middle of the sealing aluminum sheet 2. The explosion-proof structure is circular. When the pressure in the sealed battery aluminum shell exceeds the safety value, the air pressure can break through the explosion-proof structure on the sealing aluminum sheet 2, and the sealing aluminum sheet 2 is annularly disconnected from the middle, being divided into two parts: an inner circular sheet and an outer circular ring sheet. Specifically, a circular blasting blind hole 4 is provided at the core of the bottom surface of the sealing aluminum sheet 2. The diameter range of the blasting blind hole 4 is 10 - 20 mm, the depth of the blasting blind hole 4 is 0.1 - 0.5 mm, and a fillet is provided at the bottom edge of the blasting blind hole 4.

[0021] A blasting circular groove 41 is further provided on the bottom surface of the blasting blind hole 4. The thickness between the bottom of the blasting circular groove 41 and the upper surface of the sealing aluminum sheet 2 is 0.3 - 2.4 mm, and the diameter of the blasting circular groove is 8 - 15 mm. The cross-section of the blasting circular groove 41 is conical, and an explosion-proof scoring line 42 is provided at the bottom of the blasting circular groove 41. The depth of the explosion-proof scoring line forming the blasting circular groove is 0.01 - 0.2 mm. When the sealing aluminum sheet 2 and the liquid injection hole 13 are welded, the liquid injection hole 13 is directly opposite to the center of the blasting blind hole 4.

[0022] The application principle of the present utility model: The sealing aluminum sheet 2 is welded along the welding groove 3 on the liquid injection hole 13, and the liquid injection hole 13 is closed. The liquid injection hole 13 is opposite to the blasting blind hole 4 on the bottom surface of the sealing aluminum sheet 2. When the air pressure inside the battery aluminum shell is too high and exceeds the safety value, the high-pressure gas overflows from the liquid injection hole 13 and enters the blasting blind hole 4. The air pressure impacts the blasting circular groove 41. The explosion-proof scoring line 42 is the weakest part. The air pressure breaks through the explosion-proof scoring line 42, and a circle in the middle of the sealing aluminum sheet is cracked. The sealing aluminum sheet 2 cracks along the explosion-proof scoring line 42. The final cracked state may be completely split into two pieces, a circular ring and a circular sheet, or a part of the central circular sheet is still connected to the sealing aluminum sheet 2. The air pressure release can ensure the safety of the internal battery core and prevent the battery core from exploding.

[0023] The above is only several preferred embodiments of the present utility model, but the protection scope of the present utility model is not limited thereto. Any changes and substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present utility model should be covered by the protection scope of the present utility model. Therefore, the protection scope of the present utility model should be subject to the protection scope of the claims.

Claims

1. A sealing nail and a secondary battery top cover with both explosion-proof and sealing functions, characterized in that: It includes a cover plate and a sealing aluminum sheet. The cover plate is a flat aluminum sheet structure with smooth upper and lower surfaces. The cover plate is symmetrically provided with a positive electrode mounting hole and a negative electrode mounting hole on both sides. An injection hole is provided between the positive electrode mounting hole and the negative electrode mounting hole. The cover plate is rectangular, and the four corners of the cover plate are provided with round chamfers. The cover plate can be welded to the upper end of a square battery aluminum shell to seal the battery aluminum shell, and electrolyte can be injected into the battery aluminum shell through the injection hole; the sealing aluminum sheet is circular, and the diameter of the sealing aluminum sheet is larger than the diameter of the injection hole. The sealing aluminum sheet can be welded on the injection hole to seal the injection hole. An explosion-proof structure is provided in the middle of the sealing aluminum sheet, and the explosion-proof structure is in the shape of a circular hole. When the pressure in the sealed battery aluminum shell exceeds the safety value, the air pressure can break through the explosion-proof structure on the sealing aluminum sheet, and the sealing aluminum sheet is disconnected from the middle ring to be divided into a two-part structure of an inner circular sheet and an outer circular ring sheet.

2. The sealing nail and secondary battery top cover having both explosion-proof and sealing functions according to claim 1, characterized in that: The sealing aluminum sheet is an inverted truncated cone structure, and the thickness of the sealing aluminum sheet is 0.8-2.5 mm.

3. The sealing nail and secondary battery top cover having both explosion-proof and sealing functions according to claim 1, characterized in that: A circle of welding grooves is arranged near the edge of the upper surface of the sealing aluminum sheet, the depth of the welding grooves is 0.5-1.2 mm, the bottom width of the welding grooves is 0.2-1.5 mm, and a transition fillet is arranged on the upper edge of the welding grooves.

4. The sealing nail and secondary battery top cover having both explosion-proof and sealing functions according to claim 1, characterized in that: A circular blasting blind hole is provided at the bottom core of the sealing aluminum sheet, the diameter of the blasting blind hole is in the range of 10-20 mm, the depth of the blasting blind hole is in the range of 0.1-0.5 mm, and the bottom edge of the blasting blind hole is provided with a rounded corner.

5. The sealing nail and secondary battery top cover having both explosion-proof and sealing functions according to claim 4, characterized in that: The bottom surface of the blasting blind hole is also provided with a circle of blasting circular grooves, the thickness between the groove bottom of the blasting circular groove and the upper surface of the sealing aluminum sheet is 0.3-2.4mm, and the diameter of the blasting circular groove is 8-15mm.

6. The sealing nail and secondary battery top cover having both explosion-proof and sealing functions according to claim 5, characterized in that: The cross section of the blasting circular groove is conical, and a circle of explosion-proof scoring lines is arranged at the bottom of the blasting circular groove, and the depth of the explosion-proof scoring lines forming the blasting circular groove is 0.01-0.2mm.

7. The sealing nail and secondary battery top cover having both explosion-proof and sealing functions according to claim 6, characterized in that: When the sealing aluminum sheet and the injection hole are welded, the injection hole faces the center of the blasting blind hole.

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