Battery cover plate and cylindrical lithium ion battery thereof

Abstract

The utility model relates to a battery cover plate and its cylindrical lithium ion battery in the battery technical field, including steel ring, sealing element and metal pole, the sealing element is used for the insulation and corrosion prevention between steel ring and metal pole, the sealing element is circular ring hollow structure, the middle part of sealing element is the clearance hole, the vertical cross section of sealing element is the I-shaped structure, and the sealing element is the circular ring hollow structure. The bottom end face and the top end face of the sealing piece are both contact ring parts, an embedding part is arranged between the two contact ring parts, the center of the steel ring is embedded in the embedding part, the sealing piece and the steel ring are of an integrated structure through injection molding, the metal pole is arranged in the clearance hole, and no liquid leakage gap exists between the sealing piece and the steel ring. The sealing and leakage-proof performance of the battery cover plate is greatly improved, and meanwhile, the battery cover plate is effectively positioned between the steel ring and the metal pole to play a role in isolation.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a battery cover plate and a cylindrical lithium ion battery thereof. Background Art

[0002] Cylindrical battery is a battery with high capacity, long cycle life and wide operating temperature range. The structure of a typical cylindrical battery includes: shell, cover, positive electrode, negative electrode, diaphragm, electrolyte, gasket, etc. Generally, the battery shell and steel ring are the negative electrode of the battery, and the metal pole is the positive electrode of the battery. The battery shell is made of nickel-plated steel plate, and the gasket (i.e. seal) is a key component to isolate and insulate the metal pole from the shell and steel ring (positive and negative electrodes), and also plays a role in sealing and corrosion-resistant the internal electrolyte.

[0003] The seal in the existing battery is generally an injection-molded gasket, which is sleeved between the positive electrode and the cover plate for isolation and insulation. A large part of the sealing and isolation performance of the gasket depends on the force applied to it between the positive electrode and the cover plate to control the gap between the gasket and the steel ring. The smaller the gap, the stronger the sealing and isolation performance of the cover plate, resulting in instability in the sealing and isolation performance of the existing battery. Therefore, in view of these current situations, there is an urgent need to develop a battery cover plate and a cylindrical lithium-ion battery thereof to meet the needs of actual use. Summary of the invention

[0004] The utility model aims to provide a battery cover and a cylindrical lithium-ion battery thereof, so as to solve the defect that the sealing isolation performance of the existing battery is unstable, and a large part of the sealing isolation performance depends on the magnitude of the force applied to it between the positive electrode and the cover.

[0005] In order to solve the above technical problems, the utility model adopts the following technical solutions:

[0006] A battery cover includes a steel ring, a sealing member and a metal pole. A first plug-in hole is provided at the center of the steel ring. The metal pole is arranged inside the first plug-in hole, and a sealing member is arranged between the steel ring and the metal pole. The sealing member is used for insulation and corrosion protection between the steel ring and the metal pole. The sealing member is a hollow circular ring structure, and the middle part of the sealing member is an air avoidance hole. The vertical cross-section of the sealing member is an "I"-shaped structure. The bottom end face and the top end face of the sealing member are both contact ring parts, and an interlocking part is between the two contact ring parts. The center of the steel ring is interlocked inside the interlocking part. The sealing member is an integrated structure with the steel ring through injection molding, and the metal pole is arranged inside the air avoidance hole.

[0007] In the above description, as a further solution, the metal pole includes a rivet and a rivet plate, the rivet plate is arranged at the top of the steel ring, a second plug-in hole is opened in the middle of the rivet plate, the second plug-in hole and the first plug-in hole and the air avoidance hole are concentric circle structures, the rivet is arranged at the bottom of the steel ring, the middle part of the rivet is plugged into the air avoidance hole, and the top end of the rivet extends to the top of the steel ring and is plugged and fixed with the second plug-in hole, and the bottom end face of the rivet plate is in contact with the contact ring part at the top of the seal.

[0008] In the above description, as a further solution, the bottom of the rivet is a limiting plate portion extending outward, the top end surface of the limiting plate portion is in contact with the contact ring portion at the bottom of the seal, the top of the rivet is a deformation portion, and the upper edge of the second plug-in hole is provided with an inwardly inclined inclined portion, and the rivet is squeezed downward through the deformation portion to fit and contact with the inclined portion of the second plug-in hole.

[0009] A cylindrical lithium-ion battery comprises a shell, a battery cell and the above-mentioned battery cover. The shell is a cylindrical hollow structure. The interior of the shell is an inner cavity for placing the battery cell. The battery cell is embedded in the inner cavity. An opening is provided at the end of the shell. The opening and the inner cavity are conductive structures. The battery cover is fixedly and sealedly connected to the opening of the shell through the edge of the steel ring. A metal pole piece extending outward is provided at the end of the battery cell. The end of the metal pole piece is electrically connected to the bottom of the metal pole column.

[0010] In the above description, as a further solution, the top end surface of the steel ring is provided with a first pit which is recessed downward, and the edge of the steel ring is a first bent portion which is bent upward. The steel ring is embedded in the opening of the shell through the first pit, and the steel ring is laser welded and sealed with the top end surface of the first bent portion and the opening of the shell.

[0011] In the above description, as a further solution, one end of the shell away from the battery cover is a removable bottom cover, the top surface of the bottom cover is provided with a second pit recessed upward, the edge of the bottom cover is a second bent portion bent downward, the bottom cover is embedded in the opening of the shell through the second pit, and the bottom cover is laser welded and sealed to the opening of the shell through the bottom end surface of the second bent portion.

[0012] The beneficial effects produced by the utility model are as follows:

[0013] The present application relates to a battery cover and a cylindrical lithium-ion battery thereof, wherein a seal is formed as an integral structure with a steel ring by injection molding, wherein two contact ring portions of the seal and a first plug-in hole of the steel ring are integrally injection molded, and no gap through which liquid may leak exists between the seal and the steel ring, thereby greatly improving the sealing and anti-leakage performance of the battery cover, and at the same time effectively being located between the steel ring and the metal pole to play an isolating role. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1This is a schematic diagram of the exploded structure of a battery cover plate described in the first embodiment of the present utility model;

[0015] Figure 2 Schematic diagram of the structure of the cylindrical lithium-ion battery described in Example 1;

[0016] Figure 3 is a schematic cross-sectional structural diagram of the cylindrical lithium-ion battery described in Example 1;

[0017] Figure 4 for Figure 3 A is a schematic diagram of the partially enlarged structure of the middle part;

[0018] Figure 5 Schematic diagram of the internal structure of the cylindrical lithium-ion battery described in Example 1;

[0019] Figure 6 It is a schematic diagram of the structural decomposition of the cylindrical lithium-ion battery described in Example 2;

[0020] Figure 7 This is a schematic cross-sectional view of the cylindrical lithium-ion battery described in Example 2:

[0021] Figure 8 for Figure 7 A schematic diagram of the partially enlarged structure of B in the middle;

[0022] Fig. 9 It is a schematic diagram of the structural decomposition of the cylindrical lithium-ion battery described in Example 3;

[0023] Fig.10 is a schematic cross-sectional view of the cylindrical lithium-ion battery described in Example 3;

[0024] Fig.11 for Fig.10 A schematic diagram of the partially enlarged structure of C in the middle;

[0025] Fig.12 is a schematic cross-sectional view of the cylindrical lithium-ion battery described in Example 4;

[0026] In the figure: 1-steel ring, 11-first plug hole, 12-first pit, 13-first bending part, 2-sealing part, 21-air avoidance hole, 22-contact ring part, 23-embedded part, 3-metal pole, 31-rivet, 311-limiting plate part, 313-deformation part, 32-rivet sheet, 321-second plug hole, 322-inclined part, 4-shell, 41-inner cavity, 42-opening, 5-battery cell, 51-metal pole piece, 6-bottom cover, 61-second pit, 62-second bending part. DETAILED DESCRIPTION

[0027] In order to facilitate the understanding of those skilled in the art, the present invention is further described below in conjunction with the embodiments and drawings, and the contents mentioned in the implementation modes are not intended to limit the present invention. The present invention is described in detail below in conjunction with the drawings.

[0028] Embodiment 1:

[0029] See also Figure 1-4 A battery cover plate specifically implemented therein comprises a steel ring 1, a seal 2 and a metal pole 3. A first plug-in hole 11 is opened at the center of the steel ring 1, the metal pole 3 is arranged inside the first plug-in hole 11, and the seal 2 is arranged between the steel ring 1 and the metal pole 3. The seal 2 is used for insulation and corrosion protection between the steel ring 1 and the metal pole 3. The seal 2 is a hollow ring structure, and the middle part of the seal 2 is an air avoidance hole 21. The vertical cross-section of the seal 2 is an "I"-shaped structure. The bottom end face and the top end face of the seal 2 are both contact ring parts 22, and the two contact ring parts 22 are interlocking parts 23. The center of the steel ring 1 is interlocked inside the interlocking part 23. The seal 2 is an integrated structure with the steel ring 1 through injection molding, and the metal pole 3 is arranged inside the air avoidance hole 21.

[0030] The seal 2 is an integrated structure with the steel ring 1 through injection molding. The two contact ring parts 22 of the seal 2 and the first plug hole 11 of the steel ring 1 are integrally injection molded. The gap between the seal 2 and the steel ring 1 that can leak liquid is greatly reduced, which greatly improves the sealing and anti-leakage performance of the battery cover. At the same time, it is effectively located between the steel ring 1 and the metal pole 3 to play an isolation role. The specific seal 2 can be composed of polyvinylidene fluoride, which is referred to as PVDF. PVDF is a highly non-reactive thermoplastic fluorine-containing polymer with excellent properties such as anti-aging, chemical resistance, weather resistance, and ultraviolet radiation resistance. It can be injection molded as an engineering plastic to make a corrosion-resistant device for the seal ring of the battery cover.

[0031] Specifically, Figure 1 , Figure 3 and Figure 4As shown, the metal pole 3 includes a rivet 31 and a rivet sheet 32. The rivet sheet 32 ​​is arranged at the top of the steel ring 1. A second plug hole 321 is opened in the middle of the rivet sheet 32. The second plug hole 321 is concentric with the first plug hole 11 and the air-avoiding hole 21. The rivet 31 is arranged at the bottom of the steel ring 1. The middle of the rivet 31 is plugged into the air-avoiding hole 21. The top of the rivet 31 extends to the top of the steel ring 1 and is plugged and fixed with the second plug hole 321. The bottom end surface of the rivet sheet 32 ​​is in contact with the contact ring portion 22 at the top of the seal 2. The rivet sheet 32 ​​and the steel ring 1 are isolated by the contact ring portion 22 at the top of the seal 2. On the one hand, it is used to isolate the contact and conduction between the rivet sheet 32 ​​and the steel ring 1. On the other hand, the rivet sheet 32 ​​can be located above the steel ring 1 to limit the structure, thereby improving the connection stability of the metal pole 3.

[0032] Specifically, Figure 1 , Figure 3 and Figure 4 As shown, the bottom of the rivet 31 is a limiting plate portion 311 extending outward, the top surface of the limiting plate portion 311 is in conflict with the contact ring portion 22 at the bottom of the seal 2, the top of the rivet 31 is a deformation portion 313, and the upper edge of the second plug hole 321 is provided with an inwardly inclined inclined portion 322, and the rivet 31 is pressed downward by the deformation portion 313 to fit and conflict with the inclined portion 322 of the second plug hole 321. After the deformation portion 313 of the rivet 31 is pressed downward, the top of the rivet 31 can form a limiting structure with the inclined portion 322 of the rivet sheet 32 ​​through the deformation portion 313, and at the same time, the bottom of the rivet 31 is a limiting plate portion 311 extending outward, which is located below the steel ring 1 for double limiting, which can effectively lock the rivet 31 and the rivet sheet 32 ​​in the center of the steel ring 1, which helps to improve the sealing and leakage-proof performance of the battery cover.

[0033] The cylindrical lithium-ion battery comprises a shell 4, a battery cell 5 and the battery cover plate mentioned above. The shell 4 is a cylindrical hollow structure. The interior of the shell 4 is an inner cavity 41 for placing the battery cell 5. The battery cell 5 is embedded in the inner cavity 41. An opening 42 is provided at the end of the shell 4. The opening 42 and the inner cavity 41 are conductive structures. The battery cover plate is fixedly connected to the opening 42 of the shell 4 through the edge of the steel ring 1. The end of the battery cell 5 is provided with a metal pole piece 51 extending outward. The end of the metal pole piece 51 is electrically connected to the bottom of the metal pole column 3. Specifically, the end of the metal pole piece 51 is welded and fixed to the bottom of the metal pole column 3 by laser spot welding. Since laser spot welding has the characteristics of fast speed, large depth and small deformation, it can greatly protect the weak structure of the metal pole piece 51.

[0034] Embodiment 2:

[0035] See also Figure 6-8 , the parts of the second embodiment that are the same as those of the first embodiment are not repeated here.

[0036] Among them, the top surface of the steel ring 1 is provided with a first concave pit 12 that is concave downward, and the edge of the steel ring 1 is a first bent portion 13 that is bent upward. The steel ring 1 is embedded in the opening 42 of the shell 4 through the first concave pit 12, and the steel ring 1 is welded and fixed to the opening 42 of the shell 4 through the top surface of the first bent portion 13 through the laser welding process. The structure in which the steel ring 1 is concave downward and provided with the first concave pit 12 allows the edge of the steel ring 1 to form the first bent portion 13 that is bent upward, and a welding surface of the same height is formed between the top surface of the first bent portion 13 and the opening 42 of the shell 4, which facilitates welding between the steel ring 1 and the shell 4, and further increases the surface connection at the welding point between the steel ring 1 and the shell 4. At the same time, the laser welding process can greatly reduce the difficulty of welding between the steel ring 1 and the shell 4.

[0037] Embodiment three:

[0038] See also Figure 9-11 , the parts of the third embodiment that are the same as those of the first embodiment are not repeated here.

[0039] Among them, the end of the shell 4 away from the battery cover is a detachable bottom cover 6, the top surface of the bottom cover 6 is provided with a second concave pit 61 that is concave upward, the edge of the bottom cover 6 is a second bent portion 62 that is bent downward, the bottom cover 6 is embedded in the opening 42 of the shell 4 through the second concave pit 61, and the bottom cover 6 is welded and fixed to the opening 42 of the shell 4 through the bottom end surface of the second bent portion 62 by a laser welding process. The edge of the bottom cover 6 can form a second bent portion 62 that is bent downward, and its principle and function are the same as the first bent portion 13 of the steel ring 1 in the second embodiment, and both can further increase the surface connection at the welding point between the steel ring 1 and the shell 4, and reduce the difficulty of welding between the steel ring 1 and the shell 4; at the same time, the detachable split structure between the bottom cover 6 and the shell 4 is convenient for the metal pole piece 51 of the battery cell 5 to be placed in the inner cavity 41 of the shell 4 after the rivet 31 of the metal pole 3 is completed electrically connected, and finally the bottom cover 6 is welded and fixed to the shell 4, which is convenient for the assembly of the cylindrical lithium-ion battery.

[0040] Embodiment 4:

[0041] See also Fig.12 The cylindrical lithium-ion battery specifically implemented includes a shell 4, a battery cell 5 and the above-mentioned battery cover. The shell 4 is a cylindrical hollow structure. The interior of the shell 4 is an inner cavity 41 for placing the battery cell 5. The battery cell 5 is embedded in the inner cavity 41. An opening 42 is opened at the end of the shell 4. The opening 42 and the inner cavity 41 are conductive structures. The battery cover is fixedly connected to the opening 42 of the shell 4 through the edge of the steel ring 1. The end of the battery cell 5 is provided with a metal pole piece 51 extending outward, and the end of the metal pole piece 51 is electrically connected to the bottom of the metal pole 3.

[0042] The preferred connection method between the metal pole piece 51 and the metal pole post 3 is as follows: the end of the metal pole piece 51 and the bottom of the metal pole post 3 are welded and fixed by laser spot welding. Since laser spot welding has the characteristics of fast speed, large depth and small deformation, it can greatly protect the weak structure of the metal pole piece 51.

[0043] The top surface of the steel ring 1 is provided with a first concave pit 12 that is concave downwards, and the edge of the steel ring 1 is a first bent portion 13 that is bent upwards. The steel ring 1 is embedded in the opening 42 of the shell 4 through the first concave pit 12, and the steel ring 1 is welded and fixed to the opening 42 of the shell 4 through the top surface of the first bent portion 13 through the laser welding process. The structure in which the steel ring 1 is concave downwards and provided with the first concave pit 12 allows the edge of the steel ring 1 to form the first bent portion 13 that is bent upwards, and a welding surface of the same height is formed between the top surface of the first bent portion 13 and the opening 42 of the shell 4, which facilitates welding between the steel ring 1 and the shell 4, and at the same time further increases the surface connection at the welding point between the steel ring 1 and the shell 4, reducing the difficulty of welding between the steel ring 1 and the shell 4.

[0044] The end of the shell 4 away from the battery cover is a detachable bottom cover 6, the top surface of the bottom cover 6 is provided with a second recessed pit 61, the edge of the bottom cover 6 is a second bent portion 62 bent downward, the bottom cover 6 is embedded in the opening 42 of the shell 4 through the second recess 61, and the bottom cover 6 is welded and fixed to the opening 42 of the shell 4 through the bottom end surface of the second bent portion 62 by a laser welding process. The edge of the bottom cover 6 can form a second bent portion 62 bent downward, the principle and function of which are the same as the first bent portion 13 of the steel ring 1 in the second embodiment, and can further increase the surface connection between the steel ring 1 and the shell 4, reducing the difficulty of welding between the steel ring 1 and the shell 4; at the same time, the detachable split structure between the bottom cover 6 and the shell 4 is convenient for the metal pole piece 51 of the battery cell 5 to be placed in the inner cavity 41 of the shell 4 after the rivet 31 of the metal pole 3 is completed electrically connected, and finally the bottom cover 6 and the shell 4 are welded and fixed, which is convenient for the assembly of the cylindrical lithium-ion battery.

[0045] The above is only a preferred embodiment of the utility model, and does not limit the utility model in any form. Although the utility model is disclosed as a preferred embodiment as above, it is not used to limit the utility model. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of equivalent changes by using the technical content disclosed above without departing from the scope of the technical solution of the utility model. However, any simple modification, equivalent change and modification made to the above embodiments according to the technology of the utility model, which does not depart from the content of the technical solution of the utility model, belongs to the scope of the technical solution of the utility model.

Claims

1. A battery cover, comprising a steel ring, a seal and a metal pole, wherein a first plug hole is provided at the center of the steel ring, the metal pole is arranged inside the first plug hole, and the seal is arranged between the steel ring and the metal pole, and the seal is used for insulation and corrosion protection between the steel ring and the metal pole, and is characterized in that: The seal is a hollow circular structure, the middle of the seal is an air avoidance hole, the vertical cross-section of the seal is an "I"-shaped structure, the bottom end face and the top end face of the seal are both contact ring parts, the two contact ring parts are an embedded part, the center of the steel ring is embedded inside the embedded part, the seal is an integrated structure with the steel ring through injection molding, and the metal pole is arranged inside the air avoidance hole.

2. A battery cover according to claim 1, characterized in that: The metal pole comprises a rivet and a rivet sheet, the rivet sheet is arranged on the top of the steel ring, a second plug hole is opened in the middle of the rivet sheet, and the second plug hole is a concentric circle structure with the first plug hole and the air avoidance hole; The rivet is arranged at the bottom of the steel ring, the middle part of the rivet is plugged into the avoidance hole, and the top end of the rivet extends to the top of the steel ring and is plugged and fixed into the second plug hole, and the bottom end surface of the rivet sheet contacts the contact ring part at the top of the seal.

3. A battery cover according to claim 2, characterized in that: The bottom of the rivet is a limiting plate portion extending outward, and the top end surface of the limiting plate portion is in conflict with the contact ring portion at the bottom of the seal; The top of the rivet is a deformation portion, and the upper edge of the second plug hole is provided with an inwardly inclined inclined portion. The rivet is pressed downward by the deformation portion to fit and contact with the inclined portion of the second plug hole.

4. A cylindrical lithium-ion battery, comprising a housing, a battery cell and a battery cover according to any one of claims 1 to 3, characterized in that: The shell is a cylindrical hollow structure, the interior of the shell is an inner cavity for placing the battery cell, the battery cell is embedded in the inner cavity, an opening is opened at the end of the shell, the opening and the inner cavity are conductive structures, the battery cover is fixedly connected to the opening of the shell through the edge of the steel ring, and a metal pole piece extending outward is provided at the end of the battery cell, and the end of the metal pole piece is electrically connected to the bottom of the metal pole.

5. The cylindrical lithium-ion battery according to claim 4, characterized in that: The top end surface of the steel ring is provided with a first pit which is recessed downwards, and the edge of the steel ring is a first bent portion which is bent upwards. The steel ring is embedded in the opening of the shell through the first pit, and the steel ring is laser welded and sealed with the opening of the shell through the top end surface of the first bent portion.

6. The cylindrical lithium-ion battery according to any one of claims 4 or 5, characterized in that: The end of the shell away from the battery cover is a detachable bottom cover, the top surface of the bottom cover is provided with a second recessed pit that is recessed upward, the edge of the bottom cover is a second bent portion that is bent downward, the bottom cover is embedded in the opening of the shell through the second recess, and the bottom cover is laser welded and sealed to the opening of the shell through the bottom end surface of the second bent portion.

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