A lithium battery end structure and manufacturing method

Abstract

The present invention discloses a lithium battery end structure and a manufacturing method, comprising a shell, a battery cell and a current collecting sheet, etc., mainly a current collecting cap and a sealing ring sleeved on the outside of the current collecting cap are arranged outside the current collecting sheet, the current collecting cap covers the injection hole of the current collecting sheet and is conductively connected to the current collecting sheet, an inner circumferential seal is formed between the sealing ring and the current collecting cap, an outer circumferential seal is formed between the sealing ring and the shell, a cover cap is arranged outside the sealing ring and the current collecting cap, the cover cap is conductively connected to the current collecting cap, and the outer edge of the cover cap is circumferentially compressed and conductively fixed by the outer curling edge of the end of the shell; obviously, the port structure of the entire shell also achieves the effect of conductive sealing with fewer parts, and has the advantages of simple structure, compact design, better ability to improve the capacity of lithium batteries and simplify automated processing procedures; at the same time, the outer curling edge is circumferentially compressed and conductively fixed, which not only improves the structural connection strength, but also ensures the compactness of the structure, and is safer to use.

Description

Technical Field

[0001] The invention relates to a structure for sealing ends in a lithium battery manufacturing process, in particular to a lithium battery end structure and a manufacturing method. Background Art

[0002] At present, end sealing is required in the production and manufacturing process of lithium batteries. The traditional way is to seal the collector sheet at the end of the shell to seal the battery cell and electrolyte in the shell, and then set various components such as collector rings, decorative rings, sealing rings and glands on the collector sheet for conductive sealing. This port structure design is too complicated and has many components, which will occupy a large volume of the lithium battery, resulting in a decrease in the capacity of the lithium battery. At the same time, the overly complicated structure also increases the production process and increases the difficulty of automated processing. In addition, the various components on the collector sheet are pressed and fixed by the curling at the battery port. The traditional lithium battery structure only needs to fold the curling. In actual use, it is easy for the curling to fail to be pressed, resulting in poor structural compactness and electrolyte leakage, which greatly affects the safety of lithium batteries. Summary of the invention

[0003] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a lithium battery end structure and manufacturing method which is simple in structure, compact in design, can better improve the capacity of the lithium battery and simplify the automated processing procedures, and is safer to use.

[0004] The technical problem of the present invention is achieved through the following technical solutions:

[0005] A lithium battery end structure comprises an outer shell, an electric core and a current collecting sheet in the outer shell, the current collecting sheet is provided with a liquid injection hole, the current collecting sheet and the electric core are conductively connected, a current collecting cap and a sealing ring sleeved outside the current collecting cap are provided outside the current collecting sheet, the current collecting cap covers the liquid injection hole and is conductively connected to the current collecting sheet, an inner circumferential seal is formed between the sealing ring and the current collecting cap, an outer circumferential seal is formed between the sealing ring and the outer shell, a cover cap is provided outside the sealing ring and the current collecting cap, the cover cap is conductively connected to the current collecting cap, and the outer edge of the cover cap is circumferentially compressed and conductively fixed by the outer curling edge of the end of the outer shell.

[0006] The collecting cap is a fully enclosed structure or the collecting cap is provided with a collecting hole connected to the injection hole.

[0007] The current collecting sheet is provided with a convex ring protruding outward, and the injection hole is a through hole axially penetrating the convex ring.

[0008] The current collecting cap is a fully enclosed structure, and a blind hole corresponding to the position of the current collecting cap is provided on the cover cap, and the bottom of the blind hole is electrically conductively welded to the current collecting cap.

[0009] The inner diameter of the blind hole is larger than the outer diameter of the convex ring but smaller than the outer diameter of the current collecting cap, and the conductive welding between the bottom of the blind hole and the current collecting cap is located between the inner diameter of the blind hole and the outer diameter of the convex ring.

[0010] The collecting cap is provided with a collecting hole, and a corresponding cover hole connected with the collecting hole is provided on the cover cap. The inner diameter of the cover hole is larger than the inner diameter of the injection hole but smaller than the outer diameter of the collecting cap. The conductive welding between the cover cap and the collecting cap is located between the inner diameter of the cover hole and the outer diameter of the collecting cap.

[0011] An explosion-proof sealing cover and a negative electrode cap are arranged in the cover hole. The negative electrode cap is circumferentially pressed and fixed by the inner curling edge at the end of the cover hole, and the explosion-proof sealing cover is squeezed to seal and close the collecting hole. Explosion-proof valves are arranged in the explosion-proof sealing cover and the negative electrode cap.

[0012] The inner circumferential seal between the sealing ring and the current collecting cap is a conical surface seal; an insulating ring of circumferential seal is arranged between the current collecting sheet and the inner circumferential surface of the shell.

[0013] The outer curling edge directly presses the outer edge of the cap and performs conductive welding, or the outer edge of the cap is provided with an annular sealing ring, and a conductive supporting ring is arranged outside the annular sealing ring, and the outer curling edge directly presses the conductive supporting ring and performs conductive welding.

[0014] A method for manufacturing a lithium battery end structure comprises the following steps:

[0015] Step 1: Select a lithium battery shell and install a battery cell therein, and perform groove rolling on the outer circumferential surface of the end of the shell;

[0016] Step 2: Cover the injection hole of the current collecting sheet with the current collecting cap and perform conductive welding, and install an insulating ring on the outer periphery of the current collecting sheet, so that the current collecting sheet, the current collecting cap and the insulating ring are integrated into a first assembly;

[0017] Step 3: Install the sealing ring and the cap as a second assembly. If an annular sealing ring and a conductive support ring are provided on the cap, the annular sealing ring and the conductive support ring also need to be installed as a whole with the cap.

[0018] Step 4: Install the explosion-proof sealing cover and the negative electrode cap together as a third assembly;

[0019] Step 5: Install the first assembly in a sealed manner in the end of the housing so as to contact and fix it in the rolling groove, and conduct conductive welding between the current collecting sheet of the first assembly and the battery cell in the housing;

[0020] Step 6: If the current collecting cap of the first assembly is a fully enclosed structure, a blind hole corresponding to the position of the current collecting cap is provided on the cap of the second assembly. The second assembly is first installed outside the first assembly, and the cap of the second assembly is conductively welded to the current collecting cap of the first assembly through the blind hole, and then the outer edge of the cap is circumferentially pressed by the outer curling edge of the shell end and fixed by conductive welding;

[0021] Step seven, if the current collecting cap of the first assembly is provided with a current collecting hole connected to the injection hole, then the cover cap of the second assembly is provided with a cover hole connected to the current collecting hole, first install the second assembly outside the first assembly, and conduction weld the cover cap of the second assembly to the current collecting cap of the first assembly, then inject the electrolyte into the outer shell through the cover hole, the current collecting hole and the injection hole in sequence, and then install the third assembly in the cover hole of the cover cap, so that the negative electrode cap of the third assembly is circumferentially pressed and fixed by the inner curling edge at the end of the cover hole, and the explosion-proof sealing cover is squeezed to seal the current collecting hole, explosion-proof valves are provided in the explosion-proof sealing cover and the negative electrode cap, and finally the outer edge of the cover cap is circumferentially pressed and fixed by the outer curling edge at the end of the outer shell and conduction welded.

[0022] Compared with the prior art, the present invention mainly comprises a current collecting cap and a sealing ring sleeved on the outside of the current collecting cap outside the current collecting sheet, the current collecting cap covers the injection hole of the current collecting sheet and is conductively connected to the current collecting sheet, the sealing ring and the current collecting cap form an inner circumferential seal, the sealing ring and the outer shell form an outer circumferential seal, a cover cap is provided outside the sealing ring and the current collecting cap, the cover cap is conductively connected to the current collecting cap, and the outer edge of the cover cap is circumferentially compressed and conductively fixed by the outer curling edge at the end of the outer shell; obviously, since the port structure of the entire outer shell is only composed of the current collecting sheet, the current collecting cap, the sealing ring and the cover cap, the conductive sealing effect is also achieved with fewer parts, so it has the advantages of simple structure, compact design, better ability to improve the capacity of the lithium battery and simplify the automated processing procedures; at the same time, the outer curling edge is circumferentially compressed and conductively fixed, which not only improves the structural connection strength, but also ensures the compactness of the structure, and is safer to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a cross-sectional structural schematic diagram of the present invention.

[0024] Figure 2 This is a cross-sectional view of the first port structure (positive end).

[0025] Figure 3 for Figure 2 Three-dimensional half-section view.

[0026] Figure 4 A cross-sectional view of the second terminal structure (either the negative terminal or the positive terminal can be used).

[0027] Figure 5 for Figure 4 Three-dimensional half-section view.

[0028] Figure 6 It is a structural schematic diagram of the current collector.

[0029] Figure 7 for Figure 2 Schematic diagram of the cross-sectional structure of the center header cap.

[0030] Figure 8 for Figure 7 Stereoscopic diagram.

[0031] Fig. 9 for Figure 4 Schematic diagram of the cross-sectional structure of the center header cap.

[0032] Fig.10 for Fig. 9 Stereoscopic diagram.

[0033] Fig.11 for Figure 2 Schematic diagram of the cross-sectional structure of the middle cover cap.

[0034] Fig.12 for Fig.11 Stereoscopic diagram.

[0035] Fig.13 for Figure 4 Schematic diagram of the cross-sectional structure of the middle cover cap.

[0036] Fig.14 for Fig.13 Stereoscopic diagram.

[0037] Fig.15 A schematic diagram of the structure of the shell. DETAILED DESCRIPTION

[0038] The embodiments of the present invention will be described in detail below with reference to the above-mentioned drawings.

[0039] like Figure 1 to Figure 15 As shown, 1. shell, 2. battery cell, 3. current collecting sheet, 31. injection hole, 32. convex ring, 4. insulating ring, 5. sealing ring, 6. cover cap, 61. blind hole, 62. cover hole, 63. inner curling edge, 7. conductive support ring, 8. annular sealing ring, 9. current collecting cap, 91. conical seal, 92. current collecting hole, 10. explosion-proof sealing cover, 11. negative electrode cap, 12. outer curling edge, 13. rolling groove.

[0040] A lithium battery end structure and manufacturing method, such as Figure 1 As shown, it has two structural forms. The first structural form is as follows Figure 2 , Figure 3 As shown, this structure can only be used as the positive terminal. The second structure is as follows Figure 3 , Figure 4 As shown, this structural form can be used as both the negative terminal and the positive terminal. Therefore, in a lithium battery, the first structural form and the second structural form can be selected at both ends of the shell respectively, or the second structural form can be designed at both ends of the shell, that is, it can be used as both the positive terminal and the negative terminal at the same time. The combination method is flexible and convenient, and the scope of use is very wide.

[0041] For a clearer description, the present invention describes the two structural forms separately in detail. The first structural form is as follows: Figure 2 , Figure 3 , Figure 7 , Figure 8 , Fig.11 , Fig.12 As shown, this structural form is only used as a positive terminal, and its structure includes a cylindrical shell 1 of a lithium battery, a battery cell 2 and a current collector 3 arranged in the shell, and its sealing method is mainly to provide a circumferentially sealed insulating ring 4 between the current collector 3 and the inner circumferential surface of the shell 1.

[0042] The current collector 3 is disc-shaped to fit the cylindrical shell of the lithium battery. A convex ring 32 protruding outward is provided at the center of the current collector 3, and a through hole penetrating along the axis is provided in the convex ring as a liquid injection hole 31. The through hole is actually a tapered hole with a larger inner end and a smaller outer end.

[0043] When the entire tab at the end of the battery cell 2 is flattened, the current collector 3 can be conductively connected to the entire tab of the battery cell 2 by welding, that is, a conductive connection is formed between the current collector 3 and the battery cell 2 .

[0044] The collecting plate 3 is provided with a collecting cap 9 and a sealing ring 5 mounted outside the collecting cap; wherein, the collecting cap 9 is a fully enclosed structure, which will completely cover the injection hole 31 and be connected to the collecting plate 3 by conductive welding, and an inner circumferential seal is formed between the sealing ring 5 and the collecting cap 9, specifically a conical surface seal 91, which can have better sealing performance when the extrusion strength is greater, and an outer circumferential seal is formed between the sealing ring 5 and the outer shell 1.

[0045] The sealing ring 5 and the current collecting cap 9 are provided with a cover cap 6 outside. Since the current collecting cap 9 is a fully enclosed structure, a blind hole 61 corresponding to the position of the current collecting cap 9 is provided on the cover cap 6, and the bottom of the blind hole and the current collecting cap 9 are conductively welded, that is, the cover cap 6 and the current collecting cap 9 are conductively welded. Specifically, the inner diameter of the blind hole 61 is larger than the outer diameter of the convex ring 32 but smaller than the outer diameter of the current collecting cap 9, and the conductive welding between the bottom of the blind hole 61 and the current collecting cap 9 needs to be located between the inner diameter of the blind hole 61 and the outer diameter of the convex ring 32, so as to ensure the firmness of the welding strength and prevent welding through.

[0046] At the same time, the outer edge of the cap 6 is circumferentially pressed and fixed by the outer curling edge 12 at the end of the outer shell 1 for conductive fixation. Specifically, an annular sealing ring 8 is provided on the outer edge of the cap 6, and a conductive support ring 7 is provided outside the annular sealing ring. The outer curling edge 12 directly presses the conductive support ring 7 and fixes it by conductive welding, which not only increases the connection strength but also ensures the conductive reliability.

[0047] The second structural form is Figure 4 , Figure 5 , Fig. 9 , Fig.10 , Fig.13 , Fig.14 As shown, this structural form can be used as both a positive terminal and a negative terminal. Since the installation structure of the current collecting plate 3, the current collecting cap 9 and the sealing ring 5 is exactly the same as that of the positive terminal, it will not be described again here; however, the current collecting cap 9 is provided with a current collecting hole 92 connected to the injection hole 31, and a cover hole 62 connected to the current collecting hole 92 is correspondingly provided on the cover cap 6. The inner diameter of the cover hole is larger than the inner diameter of the injection hole 31 and smaller than the outer diameter of the current collecting cap 9, and the conductive welding between the cover cap 6 and the current collecting cap 9 is just located between the inner diameter of the cover hole 62 and the outer diameter of the current collecting cap 9, in order to ensure the firmness of the welding strength and prevent welding through.

[0048] An explosion-proof sealing cover 10 and a negative electrode cap 11 are provided in the cover hole 62. The negative electrode cap is circumferentially pressed by the inner curling edge 63 at the end of the cover hole 62 and fixed by conductive welding, which will squeeze the explosion-proof sealing cover 10 to seal the collecting hole 92. Explosion-proof valves are provided in the explosion-proof sealing cover 10 and the negative electrode cap 11 to form double-channel protection.

[0049] The manufacturing method of the lithium battery end structure mainly includes the following steps:

[0050] Step 1: Select a lithium battery shell 1 and install a battery cell 2 therein, and roll a groove 13 on the outer circumferential surface of the end of the shell;

[0051] Step 2: Cover the injection hole 31 of the current collecting piece 3 with the current collecting cap 9 and perform conductive welding, and install the insulating ring 4 on the outer periphery of the current collecting piece 3, so that the current collecting piece 3, the current collecting cap 9 and the insulating ring 4 are integrated into a first assembly;

[0052] Step 3: Install the sealing ring 5 and the cap 6 as a second assembly. If the cap 6 is provided with an annular sealing ring 8 and a conductive support ring 7, the annular sealing ring and the conductive support ring also need to be installed as a whole with the cap 6.

[0053] Step 4: Install the explosion-proof sealing cover 10 and the negative electrode cap 11 together to form a third assembly;

[0054] Step 5: Install the first assembly in a sealed manner in the end of the housing 1 and contact and fix it with the rolling groove 13, and conduct conductive welding between the current collecting sheet 3 of the first assembly and the battery core 2 in the housing 1;

[0055] Step 6: If the current collecting cap 9 of the first assembly is a fully enclosed structure, that is, Figure 2 , Figure 3In the structure shown, the cap 6 of the second assembly is provided with a blind hole 61 corresponding to the position of the current collecting cap 9. The second assembly is first installed outside the first assembly, and the cap 6 of the second assembly is conductively welded to the current collecting cap 9 of the first assembly through the blind hole 61, and then the outer edge of the cap 6 is circumferentially pressed by the outer curling edge 12 at the end of the shell 1 and fixed by conductive welding;

[0056] Step 7: If the manifold cap 9 of the first assembly is provided with a manifold hole 92 connected to the injection hole 31, that is, Figure 4 , Figure 5 In the structure shown, the cover hole 62 connected with the collecting hole 92 is provided on the cover cap 6 of the second assembly. The second assembly is first installed outside the first assembly, and the cover cap 6 of the second assembly is conductively welded to the collecting hole 9 of the first assembly. The electrolyte is then injected into the outer shell 1 through the cover hole 62, the collecting hole 92 and the injection hole 31 in sequence. Then, the third assembly is installed in the cover hole 62 of the cover cap 6, so that the negative electrode cap 11 of the third assembly is circumferentially pressed and fixed by the inner curling edge 63 at the end of the cover hole 62, and the explosion-proof sealing cover 10 is squeezed to seal the collecting hole 92. Explosion-proof valves are provided in the explosion-proof sealing cover 10 and the negative electrode cap 11. Finally, the outer edge of the cover cap 6 is circumferentially pressed and conductively welded by the outer curling edge 12 at the end of the outer shell 1.

[0057] Since the port structure of the entire shell of the present invention is only composed of the current collecting sheet 3, the current collecting cap 9, the sealing ring 5 and the cover cap 6, the conductive sealing effect is also achieved with fewer parts, and the structure is simple, the design is compact, and the capacity of the lithium battery can be improved and the automated processing procedure can be simplified; at the same time, the outer curling edge 12 is circumferentially compressed and conductively fixed, which not only improves the structural connection strength, but also ensures the compactness of the structure, and is safer to use.

[0058] The above description is only a specific embodiment of the present invention. Those skilled in the art should understand that any structural design similar to this embodiment should be included in the protection scope of the present invention.

Claims

1. A lithium battery end structure, comprising a housing (1), a battery cell (2) in the housing, and a current collector (3), wherein the current collector is provided with a liquid injection hole (31), and the current collector (3) is electrically connected to the battery cell (2), characterized in that The current collecting sheet (3) is provided with a current collecting cap (9) and a sealing ring (5) sleeved on the outside of the current collecting cap. The current collecting cap (9) covers the injection hole (31) and is conductively connected to the current collecting sheet (3). An inner circumferential seal is formed between the sealing ring (5) and the current collecting cap (9), and an outer circumferential seal is formed between the sealing ring (5) and the housing (1). A cover cap (6) is provided outside the sealing ring (5) and the current collecting cap (9). The cover cap is conductively connected to the current collecting cap (9), and the outer edge of the cover cap (6) is circumferentially pressed and conductively fixed by the outer curling edge (12) at the end of the housing (1); The method for manufacturing the lithium battery end structure comprises the following steps: Step 1: Select a lithium battery shell (1) and install a battery cell (2) therein, and roll grooves (13) on the outer circumferential surface of the end of the shell; Step 2: Cover the injection hole (31) of the current collecting plate (3) with the current collecting cap (9) and perform conductive welding, and install an insulating ring (4) on the outer periphery of the current collecting plate (3), so that the current collecting plate (3), the current collecting cap (9) and the insulating ring (4) are integrated into a first assembly; Step 3: Install the sealing ring (5) and the cover cap (6) as a second assembly. If the cover cap (6) is provided with an annular sealing ring (8) and a conductive support ring (7), the annular sealing ring and the conductive support ring also need to be installed as a whole with the cover cap (6); Step 4: Install the explosion-proof sealing cover (10) and the negative electrode cap (11) together to form a third assembly; Step 5: The first assembly is sealed and installed in the end of the housing (1) so as to be in contact and fixed with the rolling groove (13), and the current collecting sheet (3) of the first assembly is conductively welded to the battery cell (2) in the housing (1); Step 6: If the current collecting cap (9) of the first assembly is a fully enclosed structure, a blind hole (61) corresponding to the position of the current collecting cap (9) is provided on the cover cap (6) of the second assembly, the second assembly is first mounted outside the first assembly, and the cover cap (6) of the second assembly is conductively welded to the current collecting cap (9) of the first assembly through the blind hole (61), and then the outer edge of the cover cap (6) is circumferentially pressed by the outer curling edge (12) at the end of the housing (1) and fixed by conductive welding; Step 7: If the current collecting cap (9) of the first assembly is provided with a current collecting hole (92) connected to the injection hole (31), the cover cap (6) of the second assembly is provided with a cover hole (62) connected to the current collecting hole (92), the second assembly is first installed outside the first assembly, and the cover cap (6) of the second assembly is conductively welded to the current collecting cap (9) of the first assembly, and then the electrolyte is injected into the housing (1) through the cover hole (62), the current collecting hole (92) and the injection hole (31) in sequence. ), and then installing the third assembly in the cover hole (62) of the cover cap (6), so that the negative electrode cap (11) of the third assembly is circumferentially pressed and fixed by the inner curling edge (63) at the end of the cover hole (62), and the explosion-proof sealing cover (10) is squeezed to seal the collecting hole (92), and explosion-proof valves are provided in the explosion-proof sealing cover (10) and the negative electrode cap (11). Finally, the outer edge of the cover cap (6) is circumferentially pressed and fixed by the outer curling edge (12) at the end of the housing (1) and conductively welded.

2. A lithium battery end structure according to claim 1, characterized in that The collecting cap (9) is a fully enclosed structure or the collecting cap (9) is provided with a collecting hole (92) communicating with the injection hole (31).

3. A lithium battery end structure according to claim 2, characterized in that The current collecting plate (3) is provided with a convex ring (32) protruding outwards, and the injection hole (31) is a through hole axially penetrating the convex ring (32).

4. A lithium battery end structure according to claim 3, characterized in that The current collecting cap (9) is a fully enclosed structure, and a blind hole (61) corresponding to the position of the current collecting cap (9) is provided on the cover cap (6), and conductive welding is performed between the bottom of the blind hole and the current collecting cap (9).

5. A lithium battery end structure according to claim 4, characterized in that The inner diameter of the blind hole (61) is larger than the outer diameter of the convex ring (32) but smaller than the outer diameter of the current collecting cap (9), and the conductive welding between the bottom of the blind hole (61) and the current collecting cap (9) is located between the inner diameter of the blind hole (61) and the outer diameter of the convex ring (32).

6. A lithium battery end structure according to claim 3, characterized in that The collecting cap (9) is provided with a collecting hole (92), and the cover cap (6) is correspondingly provided with a cover hole (62) connected to the collecting hole (92), the inner diameter of the cover hole being larger than the inner diameter of the injection hole (31) but smaller than the outer diameter of the collecting cap (9), and the conductive welding between the cover cap (6) and the collecting cap (9) is located between the inner diameter of the cover hole (62) and the outer diameter of the collecting cap (9).

7. A lithium battery end structure according to claim 6, characterized in that An explosion-proof sealing cover (10) and a negative electrode cap (11) are provided in the cover hole (62). The negative electrode cap is circumferentially pressed and fixed by an inner curling edge (63) at the end of the cover hole (62), and squeezes the explosion-proof sealing cover (10) to seal and close the collecting hole (92). Explosion-proof valves are provided in the explosion-proof sealing cover (10) and the negative electrode cap (11).

8. A lithium battery end structure according to claim 1, characterized in that The inner circumferential seal between the sealing ring (5) and the current collecting cap (9) is a conical surface seal (91); and an insulating ring (4) for circumferential sealing is provided between the current collecting sheet (3) and the inner circumferential surface of the housing (1).

9. A lithium battery end structure according to claim 1, characterized in that The outer curling edge (12) directly presses the outer edge of the cap (6) and performs conductive welding, or the outer edge of the cap (6) is provided with an annular sealing ring (8), and a conductive support ring (7) is provided outside the annular sealing ring, and the outer curling edge (12) directly presses the conductive support ring (7) and performs conductive welding.

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