Cover plate and negative collector plate connecting structure and cylindrical battery

Abstract

The utility model discloses a connecting structure of a cover plate and a cathode collector plate and a cylindrical battery, the cover plate is provided with a micro boss which slightly protrudes towards the inside of the battery, the top end of the micro boss is a platform, the middle part of the cathode collector plate is provided with an annular second nick, and the platform is welded with the inner side area of the second nick. In the application, the cover plate is provided with a structure slightly protruding towards the inside of the battery, the top end of the slightly-protruding structure is provided with a plane platform, the cover plate is externally welded with the inner ring of the collector plate through the plane platform, the inner ring of the collector plate is provided with a circle of nicks, and the welding area of the cover plate and the collector plate is in the nicks, so that when the internal pressure of the battery exceeds a certain value, the slightly-protruding surface of the cover plate rotates reversely, and the nick weak area of the collector plate is torn; therefore, the positive electrode and the negative electrode of the battery are disconnected, and battery explosion caused by external short circuit is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium battery structures, and in particular to a cover plate and a negative electrode current collecting disc connection structure and a cylindrical battery. Background Art

[0002] The full-ear large cylindrical battery is a new form of lithium battery, which adopts full-ear and rolling groove sealing or laser sealing welding. The full-ear large cylindrical battery has lower internal resistance and higher charge and discharge rate. The full-ear large cylindrical battery is the most promising development direction in the future. In addition, in addition to the low internal resistance, the full-ear large cylindrical battery has the positive and negative poles on the same side and the explosion-proof valve on the other side, which has great advantages for PACK welding and safety. Even if the battery explodes, it will not affect the PACK welding line.

[0003] For the current large cylindrical batteries with full-tab batteries, if an external short circuit occurs, the battery will remain electrically connected before the battery explodes. Since the circuit is always on, the battery will continue to short-circuit until the battery explodes. There is a lack of an intermediate disconnect mechanism to prevent the battery from exploding due to a short circuit. Utility Model Content

[0004] In view of the technical problems pointed out in the above background technology, the purpose of the utility model is to provide a cover plate and negative electrode current collecting plate connection structure and a cylindrical battery.

[0005] To achieve the above purpose, the technical solution provided by the utility model is as follows:

[0006] The first aspect of the present application provides a connection structure between a cover plate and a negative electrode current collector disk, which is applied to a cylindrical battery, wherein the cover plate is provided with a micro-boss which protrudes toward the interior of the battery and can be reversed under the action of the internal pressure of the battery, the top of the micro-boss is a platform, and the middle part of the negative electrode current collector disk is provided with a second annular notch, and the platform is welded to the inner area of ​​the second notch.

[0007] Furthermore, the second notch is V-shaped and has a depth of 0.1-0.3 mm.

[0008] Furthermore, the circumference of the second notch is evenly or unevenly spaced with penetrating slots.

[0009] Furthermore, the micro-protrusion has a height of 1-2.5 mm.

[0010] Furthermore, the micro-protrusion has a height sufficient to be pressed against the negative electrode current collecting disk, and is connected by interference fit, with an interference amount of 0.2-0.5 mm.

[0011] Furthermore, the cover plate is made of steel and has a thickness of 0.3-0.6 mm.

[0012] Furthermore, the inner area of ​​the second notch is covered with an annular steel sheet, and the platform is welded to the steel sheet.

[0013] Furthermore, the thickness of the steel sheet is 1-1.5 mm.

[0014] Further, the outer circle of the cover plate is provided with a circle of first grooves, the outer side of the first groove has an annular protrusion, the inner circle thereof is provided with the micro-protrusion, the outer circle of the micro-protrusion is provided with a circle of first notches, and the center of the platform is provided with a first center hole;

[0015] A second central hole is arranged in the middle of the negative electrode current collecting disk.

[0016] The second aspect of the present application provides a cylindrical battery, including a cover plate, a negative electrode current collector, an electrode group, a negative electrode insulating glue, a glue nail, a sealing sheet, a positive electrode current collector, a positive electrode insulating glue, and a battery shell; the cover plate and the negative electrode current collector are connected through the cover plate and the negative electrode current collector connection structure as described above.

[0017] Compared with the prior art, the beneficial effects of the utility model are:

[0018] 1. The cover plate in the present application is increased with a micro-protrusion, which can be reversed when the internal pressure of the battery is too large to disconnect the circuit. The inner circle of the negative electrode collector disk has a second notch. When the cover plate is reversed, the negative electrode collector disk will tear at the second notch, disconnecting the connection between the cover plate and the negative electrode, cutting off the internal circuit of the battery, and avoiding battery explosion and battery explosion.

[0019] 2. In addition, the present application welds a steel sheet in the middle of the negative electrode current collector, which increases the thickness. The cover plate is also made of steel, which will improve the welding qualification rate during the cover plate penetration welding and the negative electrode current collector welding. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the explosion structure of a cylindrical battery provided in an embodiment of the present application;

[0021] In the figure, cover plate 1, negative electrode current collector plate 2, electrode group 3, negative electrode insulating glue 4, glue nail 5, sealing sheet 6, positive electrode current collector plate 7, positive electrode insulating glue 8, battery case 9;

[0022] Figure 2 A schematic diagram of the cross-sectional structure of a cylindrical battery provided in an embodiment of the present application;

[0023] Figure 3 A first schematic diagram of the structure of a cover plate provided in an embodiment of the present application;

[0024] Figure 4 for Figure 3 Schematic diagram of the AA section structure along the middle edge;

[0025] Figure 5A second schematic diagram of the structure of the cover plate provided in an embodiment of the present application;

[0026] In the figure, micro boss 11, platform 12, first center hole 13, first groove 14, protruding edge 15, first notch 16;

[0027] Figure 6 A first schematic diagram of the structure of a negative electrode current collector provided in an embodiment of the present application;

[0028] Figure 7 for Figure 6 Schematic diagram of the cross-sectional structure along the middle edge BB;

[0029] Figure 8 A second schematic diagram of the structure of the negative electrode current collector provided in an embodiment of the present application;

[0030] In the figure, the second center hole 21, the second notch 22, the steel sheet 23, and the umbrella-shaped surface 24;

[0031] Fig. 9 A schematic diagram of the cross-sectional structure of a rubber nail provided in an embodiment of the present application;

[0032] Fig.10 A schematic diagram of the structure of the rubber nail provided in the embodiment of the present application;

[0033] In the figure, a cylinder 51, a chamfer 52, and a truncated cone 53;

[0034] Fig.11 A first schematic diagram of the structure of a sealing sheet provided in an embodiment of the present application;

[0035] Fig.12 for Fig.11 Schematic diagram of the CC section structure along the middle edge;

[0036] Fig.13 A second schematic diagram of the structure of the sealing sheet provided in an embodiment of the present application;

[0037] In the figure, the first boss 61 and the first platform surface 62;

[0038] Fig.14 A schematic diagram of the structure of a battery case provided in an embodiment of the present application;

[0039] Fig.15 for Fig.14 Schematic diagram of the DD section structure along the middle edge;

[0040] In the figure, the housing 91, the gasket 92, the sealing ring 93, the positive pole 94, and the second groove 941;

[0041] Fig.16 A first schematic diagram of the structure of a positive electrode current collector provided in an embodiment of the present application;

[0042] Fig.17 for Fig.16 Schematic diagram of the EE cross-section structure along the middle edge;

[0043] Fig.18 A second schematic diagram of the structure of the positive electrode current collecting disk provided in an embodiment of the present application;

[0044] In the figure, the second boss 71 and the second platform surface 72;

[0045] Fig.19 This is a schematic diagram of the cross-sectional structure of a cylindrical battery after the cover provided in an embodiment of the present application is reversed. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0047] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0048] In the description of this patent, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "set" should be understood in a broad sense, for example, it can be fixedly connected or set, or it can be detachably connected or set, or connected or set in one piece. For ordinary technicians in this field, the specific meanings of the above terms in this patent can be understood according to specific circumstances.

[0049] like Figure 1-Figure 19 The figure is a schematic diagram of the structure of an embodiment of the present application.

[0050] Example 1

[0051] The present embodiment provides a connection structure between a cover plate and a negative electrode current collecting disk, which is applied to a cylindrical battery. The cover plate 1 is provided with a micro-boss 11 which protrudes toward the inside of the battery and can be reversed under the action of the internal pressure of the battery. The top of the micro-boss 11 is a platform 12. The middle of the negative electrode current collecting disk 2 is provided with an annular second notch 22, and the platform 12 is welded to the inner area of ​​the second notch 22.

[0052] The battery cover and current collecting plate designed in this embodiment have a cover with a structural micro-boss that is slightly convex toward the inside of the cylindrical battery, and a platform on the top of the micro-boss, which is welded to the outside and the inner circle of the negative current collecting plate through the platform. The inner circle of the negative current collecting plate has a circle of second notches, and the welding area between the cover and the negative current collecting plate is in the inner area of ​​the second notch. When the internal pressure of the battery exceeds a certain value, the micro-boss of the cover will reverse and tear the weak area of ​​the second notch of the current collecting plate, thereby disconnecting the positive and negative poles of the battery and avoiding battery explosion caused by external short circuit problems.

[0053] It should be noted that the structure provided in this embodiment can be applied to 4695 batteries, etc.

[0054] In a preferred embodiment, the second notch 22 is V-shaped, with a depth of 0.1-0.3 mm, preferably 0.15 mm. The second notch 22 may be one circle or two circles, etc. In addition, to reduce the rupture force, the second notch may be provided with penetrating slots at even intervals or uneven intervals around the circumference.

[0055] In a preferred embodiment, the height of the micro-protrusion 11 is such that it can be pressed tightly against the negative electrode current collector, and a slight interference is required. According to the tolerance of the electrode group, the interference is generally 0.2-0.5 mm, and the height of the micro-protrusion is 1-2.5 mm.

[0056] In a preferred embodiment, a steel sheet 23 can be welded to the inner area of ​​the second notch 22. The function of the steel sheet is to weld the platform 12 to the steel sheet 23 during subsequent laser welding. The cover plate and the steel sheet are made of the same material for easy welding, and the steel sheet increases the thickness of the negative electrode current collector, making welding easier. The thickness of the steel sheet can be 1-1.5 mm, and preferably, the thickness of the steel sheet is 1 mm.

[0057] In a preferred embodiment, the outer circle of the cover plate 1 is provided with a circle of first grooves 14, the outer side of the first groove 14 has an annular protrusion 15, the inner circle thereof is provided with the micro-boss 11, the outer circle of the micro-boss is provided with a circle of first notches 16, and the center of the platform 12 is provided with a first center hole 13.

[0058] Among them, the depth of the first groove 14 can be 1-2mm, and its function is to position the cover plate after it is placed in the shell of the battery shell, to ensure that it is concentric with the shell of the battery shell, and to have a pressing effect on the pole group; wherein, the length of the protrusion 15 can be 0.4mm, which is less than the shell wall thickness of the battery shell, to ensure that the outer diameter of the battery after welding does not exceed 46mm. Among them, the outer diameter of the first notch 16 can be 33-38mm, and the notch depth is generally 0.3-0.5mm according to the requirements of the rupture pressure, and the preferred first notch depth is 0.3mm. When the internal pressure of the battery increases due to a short circuit or other reasons, when the pressure increases to a certain value, the micro-boss 11 will reverse under the action of pressure, and the negative electrode collector will break at the second notch 22, so that the negative electrode of the pole group and the cover plate are disconnected, the internal circuit of the battery is cut off, and the battery is prevented from bursting. After the micro-boss 11 is reversed, if the internal pressure continues to increase, the cover plate will rupture at the first notch 16, releasing the internal pressure to avoid battery explosion.

[0059] In a preferred embodiment, the cover plate 1 can be made of SPCC, and the thickness can be 0.3-0.6 mm according to the required reversal pressure. After stamping, if it is not a pre-plated steel plate, nickel plating is performed, and the thickness is preferably 0.4 mm.

[0060] There is a platform 12 on the top of the micro-convex platform, and a first central hole 13 is provided in the center of the platform 12, which is a liquid injection hole. The platform diameter can be 10-16 mm, preferably 14 mm, and the platform is used for welding with the negative electrode collector. The diameter of the first central hole 13 can be 2-4 mm, preferably 3 mm.

[0061] In a preferred embodiment, a second central hole 21 is provided in the middle of the negative electrode current collecting disc 2. The diameter of the second central hole 21 is larger than that of the first central hole, and is selected to be 2.5-6 mm, preferably 5 mm.

[0062] In a preferred embodiment, the second notched outer ring may be evenly distributed with sector-shaped surfaces 24, the function of which is that the gaps provided at the sector-shaped edges facilitate the infiltration of electro-liquid during liquid injection.

[0063] Example 2

[0064] This embodiment provides a cylindrical battery, which is a welded sealed full-ear battery. It includes a cover plate 1, a negative electrode current collector 2, an electrode group 3, a negative electrode insulating glue 4, a glue nail 5, a sealing sheet 6, a positive electrode current collector 7, a positive electrode insulating glue 8, and a battery shell 9; the cover plate 1 and the negative electrode current collector 2 are connected by the cover plate and negative electrode current collector connection structure described in Example 1.

[0065] It should be noted that this embodiment can be applied to 4695 batteries, etc.

[0066] In a preferred embodiment, the battery shell 9 includes a shell 91 , a gasket 92 , a sealing ring 93 and a positive electrode column 94 , and the inner circle of the positive electrode column 94 is provided with a third groove 941 .

[0067] In a preferred embodiment, the shell 91 can be made of a 0.6mm thick steel plate made of SPCC. After stamping, the bottom thickness is 0.6mm, the wall thickness is 0.4mm, the outer diameter is 46mm, and the height can be 94-95mm. After the shell is stamped, if it is not a pre-plated steel plate, nickel plating is performed, and then the gasket, sealing ring and sealing ring are placed in the hole at the bottom of the battery shell, and then the positive electrode column is placed. The positive electrode column is stamped and the sealing ring and gasket are pressed through the flange stamped by the positive electrode column to achieve the effect of sealing and insulation.

[0068] In a preferred embodiment, the electrode group 3 is a full-electrode-tab electrode group, one end of which is a positive electrode and the other end is a negative electrode. The electrode tabs can be flattened by kneading the entire electrode tabs or by flattening after die cutting.

[0069] In a preferred embodiment, the thickness of the positive electrode collector 7 is 0.2-0.4 mm, the outer diameter is smaller than the electrode group diameter, the material is aluminum, and the thickness is preferably 0.4 mm. A second boss 71 is provided in the middle of the positive electrode collector 7, and the height of the second boss 71 is greater than that of the third groove to ensure that the surface of the second boss and the positive electrode column are pressed tightly during welding, and a second platform surface 72 is provided on the outer ring.

[0070] In a preferred embodiment, the positive electrode insulating adhesive 8 is made of high temperature resistant adhesive tape made of PI. After the positive electrode current collecting disk is welded, it is wrapped around the outside of the current collecting disk to prevent the positive and negative electrodes from short-circuiting.

[0071] In a preferred embodiment, the negative electrode current collecting disk 2 has a thickness of 0.2-0.4 mm, an outer diameter smaller than the electrode group diameter, and is made of pure copper. For easier laser welding, it can be nickel-plated, and the thickness is preferably 0.2 mm, copper-plated nickel.

[0072] In a preferred embodiment, the negative electrode insulating adhesive 4 is made of high temperature resistant adhesive tape made of PI. After the negative electrode current collecting disc is welded, it is wrapped around the outside of the current collecting disc to ensure insulation between the negative electrode current collecting disc and the shell.

[0073] In a preferred embodiment, the outer diameter of the plastic nail 5 matches the first center hole, and the diameter can be 2-4 mm. It includes a cylinder 51, and one end of the cylinder 51 has a chamfer 52 and the other end has a truncated cone 53;

[0074] In a preferred embodiment, the sealing sheet 6 may have a thickness of 0.2-0.4 mm, a first boss 61 is provided in the middle, and a first platform surface 62 is provided on the outer ring.

[0075] During assembly, the second platform surface 72 is welded to the positive end of the electrode group 3, the second boss 71 is inserted into the third column groove 941, penetrates the positive column from the outside and is welded together, the outer ring of the positive current collector is wrapped with the positive insulating tape 8 to prevent the positive electrode and the shell from short circuiting, the negative end of the electrode group 3 is welded to the negative current collector 2, and can be welded on the evenly distributed fan-shaped surface 24, the outer ring of the negative current collector is wrapped with the negative insulating glue 4, the cover plate 1 and the inner wall of the battery shell are positioned by the outer wall of the first groove 14, the outer protrusion 15 is welded to the battery shell mouth by laser peripheral welding, the platform 12 of the cover plate 1 is welded to the steel sheet 23 of the negative current collector by penetration welding, the cylinder 51 of the glue nail 5 is inserted into the first center hole 13 of the cover plate 1, the frustum 53 is pressed against the surface of the platform 12, the first boss 61 of the sealing sheet 6 is sleeved on the frustum 53, the first platform surface 62 and the platform 12 are tightly attached, and the sealing sheet and the cover plate are welded together by laser welding.

[0076] Battery production process: positive and negative electrode sheets (if die-cutting and flattening process is adopted, after die-cutting) are wound together with the diaphragm. After winding, the positive and negative electrode ears are flattened or flattened, and then the positive and negative current collectors are welded by laser welding. After welding, the positive and negative current collectors are wrapped with insulating glue. The battery shell materials have been assembled, the positive electrode column has been stamped on the bottom of the battery shell, and the sealing and insulation requirements are met. Then the shell is entered, and the positive terminal enters the bottom of the shell. Then the positive electrode column and the positive current collector are welded together from the outside by laser penetration welding, and then the cover is buckled, and the periphery of the cover and the battery shell mouth are welded by laser welding. Then the laser penetration welding is used to penetrate the cover and weld the cover to the steel sheet of the negative current collector, and helium is used to detect leakage, and then the first liquid injection, static, negative pressure formation, and second liquid injection are carried out, and then the glue nails are inserted, and the sealing sheet and the cover are welded by laser welding. After cleaning, UV anti-rust glue is applied, capacity is divided, and sorting is carried out, the battery production and shipment are completed.

[0077] The above shows and describes the basic principle, main features and advantages of the utility model. Those skilled in the art should understand that the utility model is not limited by the above embodiments. The above embodiments and descriptions are only preferred examples of the utility model and are not used to limit the utility model. Without departing from the spirit and scope of the utility model, the utility model may have various changes and improvements, which fall within the scope of the utility model to be protected. The scope of protection of the utility model is defined by the attached claims and their equivalents.

Claims

1. A cover plate and negative electrode current collector connection structure, applied to a cylindrical battery, characterized in that: The cover plate (1) is provided with a micro-protrusion (11) which protrudes toward the inside of the battery and can be reversed under the action of internal pressure of the battery, the top of the micro-protrusion (11) is a platform (12), the middle of the negative electrode current collector (2) is provided with an annular second notch (22), and the platform (12) is welded to the inner area of ​​the second notch (22).

2. A cover plate and negative electrode current collecting plate connection structure according to claim 1, characterized in that: The second notch (22) is V-shaped and has a depth of 0.1-0.3 mm.

3. The cover plate and negative electrode current collecting plate connection structure according to claim 1, characterized in that: The second notch (22) is provided with penetrating slots at even or uneven intervals around its circumference.

4. The cover plate and negative electrode current collecting plate connection structure according to claim 1, characterized in that: The height of the micro-protrusion (11) is 1-2.5 mm.

5. The cover plate and negative electrode current collecting plate connection structure according to claim 1, characterized in that: The micro-protrusion (11) has a height sufficient to be pressed tightly against the negative electrode current collecting plate (2), and is connected by interference fit, with an interference amount of 0.2-0.5 mm.

6. The cover plate and negative electrode current collecting plate connection structure according to claim 1, characterized in that: The cover plate (1) is made of steel and has a thickness of 0.3-0.6 mm.

7. The cover plate and negative electrode current collecting plate connection structure according to claim 1, characterized in that: The inner area of ​​the second notch (22) is covered with an annular steel sheet (23), and the platform (12) is connected to the steel sheet (23) by welding.

8. A cover plate and negative electrode current collecting plate connection structure according to claim 7, characterized in that: The thickness of the steel sheet (23) is 1-1.5 mm.

9. The cover plate and negative electrode current collecting plate connection structure according to claim 1, characterized in that: The outer ring of the cover plate (1) is provided with a circle of first grooves (14), the outer side of the first groove (14) is provided with an annular protrusion (15), the inner ring is provided with the micro-protrusion (11), the outer ring of the micro-protrusion is provided with a circle of first notches (16), and the center of the platform (12) is provided with a first center hole (13); A second central hole (21) is provided in the middle of the negative electrode current collecting disk (2).

10. A cylindrical battery, characterized in that: The invention comprises a cover plate (1), a negative electrode current collecting plate (2), an electrode group (3), a negative electrode insulating glue (4), a glue nail (5), a sealing sheet (6), a positive electrode current collecting plate (7), a positive electrode insulating glue (8), and a battery shell (9); the cover plate (1) and the negative electrode current collecting plate (2) are connected via a cover plate and a negative electrode current collecting plate connecting structure as described in any one of claims 1 to 9.

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