Cylindrical battery and assembly process of cylindrical battery

Abstract

The invention provides a cylindrical battery and an assembly process of the cylindrical battery. The cylindrical battery comprises a battery cell, a shell for accommodating the battery cell and a cover plate assembly for sealing the shell, the cover plate assembly comprises a top cover plate, a first collector plate and an insulating part, the insulating part is arranged between the top cover plate and the first collector plate, the top cover plate seals the shell and is provided with a first through hole, the first collector plate comprises a substrate and a pole connected with the substrate, the substrate is welded and fixed to a tab of one pole in the battery cell, and the pole penetrates through and is electrically insulated from the first through hole; the top cover piece is provided with a plurality of second through holes around the first through hole, sealing pieces are arranged in the second through holes, and the insulating piece is provided with third through holes corresponding to the second through holes. According to the cylindrical battery, through structural improvement, flexible connection can be omitted, and the first collector plate is directly welded with the tab of one pole in the battery cell, so that the use requirement of a high-magnification battery can be met.

Description

Technical Field

[0001] This invention relates to the field of new energy storage equipment technology, and in particular to a cylindrical battery and a cylindrical battery assembly process. Background Technology

[0002] Electric vehicles, due to their advantages such as energy saving and low pollution, have become the main direction of contemporary automotive development and a new growth point for the automotive industry. All of this requires the emergence of power batteries. A power battery is a power source that provides power to tools, primarily referring to the batteries that power electric vehicles, electric trains, electric bicycles, and golf carts.

[0003] Based on their shape, power batteries typically include cylindrical batteries and prismatic batteries. Cylindrical batteries, due to their shape, are easier to dissipate heat when assembled into packs, resulting in longer battery life. Therefore, cylindrical batteries are more commonly used in modules with high heat dissipation requirements.

[0004] Traditional cylindrical power batteries typically consist of a cell, a casing housing the cell, and a cover plate, with the casing and one of the cell's terminals (usually the negative terminal) electrically connected. The cover plate includes a top cover plate, terminals, insulators, seals, and a first current collector plate. The first current collector plate and the top cover plate, as well as the top cover plate and terminals, are insulated by the insulators. Through-holes are formed in the top cover plate, through which the terminals pass and are sealed by the seals. The upper part of the first current collector plate and the lower part of the terminals are laser-welded. The lower part of the first current collector plate and the other terminal's tab (usually the positive terminal) are laser-welded via a flexible connector; one end of the flexible connector is laser-welded to the first current collector plate, and the other end is laser-welded to the tab. During battery assembly, after the cover plate is assembled, the flexible connector is used to weld the cover plate to the cell, and then the top cover plate within the cover plate is welded to the casing. Because current welding processes make it difficult to directly weld the lower part of the first current collector plate to the other terminal of the cell, the use of flexible connectors cannot be eliminated. The presence of flexible connectors extends the current flow path, and flexible connectors usually need to meet folding requirements to take up as little space as possible. Therefore, the horizontal line in the middle is small, which makes it easy to melt at high rates. In addition, the structural design of flexible connectors also has the problem of unstable connection and easy loosening, so it is difficult to meet the use requirements of high-rate batteries. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to provide a cylindrical battery and its assembly process. This cylindrical battery, through structural improvements, eliminates the need for flexible connections, allowing direct welding of the first current collector plate and the tab of one electrode in the cell, thus meeting the requirements for high-rate batteries.

[0006] To achieve the above objectives, a first aspect of the present invention provides a cylindrical battery, comprising a cell, a housing containing the cell, and a cover assembly for sealing the housing. The cover assembly includes a top cover plate, a first current collector plate, and an insulating member. The insulating member is located between the top cover plate and the first current collector plate. The top cover plate seals the housing and has a first through hole. The first current collector plate includes a substrate and an electrode post connected to the substrate. The substrate is welded and fixed to an electrode tab of one electrode in the cell. The electrode post passes through and is electrically insulated from the first through hole. The top cover plate has a plurality of second through holes around the first through hole. A sealing member is provided in each of the second through holes. The insulating member has a third through hole corresponding to each of the second through holes.

[0007] In the cylindrical battery of the present invention, the top cover sheet is provided with a plurality of second through holes around the first through hole, and the insulating component is provided with a third through hole corresponding to the second through hole. Therefore, before the sealing component is installed in the second through hole, the welding head of the through welding can be inserted through the second through hole and the third through hole to achieve the welding and fixing of the substrate of the first current collector and the electrode tab of one electrode in the cell. Thus, the use of the soft connection can be eliminated, the current flow path can be shortened, the connection reliability can be enhanced, and the melting problem under high rate can be avoided, thus meeting the use requirements of high rate batteries.

[0008] As one technical solution of the present invention, there are four second through holes, which are arranged regularly around the first through hole.

[0009] As one technical solution of the present invention, the substrate and the pole are either an integral structure or a separate structure.

[0010] As a technical solution of the present invention, the insulating member includes a body portion and a first extension portion formed by the body portion extending toward the top cover plate. The body portion is located between the substrate and the top cover plate and is provided with a fourth through hole for the electrode post to pass through. The first extension portion is located between the electrode post and the top cover plate and is provided with a fifth through hole for the electrode post to pass through. The body portion is provided with the third through hole.

[0011] As a technical solution of the present invention, the insulating member further includes a second extension portion formed by the body portion extending in a direction away from the top cover sheet, the second extension portion being located between the substrate and the housing.

[0012] As a technical solution of the present invention, the insulating member further includes a bending portion, which is located at the end of the first extension portion away from the body portion, and the bending portion and the first extension portion enclose a space that can be snapped onto the top cover sheet.

[0013] As a technical solution of the present invention, the sealing element extends at least into the third through hole.

[0014] As a technical solution of the present invention, the substrate is provided with a blind hole with an opening away from the battery cell corresponding to the second through hole.

[0015] As a technical solution of the present invention, the bottom of the blind hole protrudes from the substrate to form a first protrusion, and the first protrusion is connected to one electrode in the battery cell.

[0016] As a technical solution of the present invention, the battery cell includes a first electrode, a separator, and a second electrode. The separator is located between the first electrode and the second electrode. The first electrode includes a first diaphragm and a first tab. The second electrode includes a second diaphragm and a second tab. The first diaphragm, the separator, and the second diaphragm are stacked and wound to form a core body. The first tab and the second tab are respectively protruding on opposite sides of the core body. The first tab is bent and welded to the first protrusion.

[0017] As a technical solution of the present invention, a second current collector is provided between the battery cell and the housing. The second current collector is provided with a plurality of second protrusions in the direction facing the battery cell. The second electrode tab is bent and welded to the second protrusions.

[0018] A second aspect of the present invention provides an assembly process for a cylindrical battery, comprising the steps of:

[0019] (1) Assemble the top cover plate, the first current collector and the insulating component into the cover plate assembly;

[0020] (2) The battery cell is housed in the housing;

[0021] (3) Weld the housing and the top cover plate together;

[0022] (4) Pass the through-welding head through the second through hole and the third through hole, and weld the substrate and the electrode tab of one pole in the cell;

[0023] (5) Seal the second through hole by injecting sealant or by using a sealing pin;

[0024] (6) The tab of the other pole of the battery cell and the bottom of the housing are welded together.

[0025] In the assembly process of the cylindrical battery of the present invention, the design of the second through hole and the third through hole can realize through welding. Therefore, after the shell and the top cover are welded, the tab of one pole of the cell and the substrate can be through welded, without the need for laser welding using soft connection as in traditional battery assembly, thereby meeting the requirements of high-rate battery use. Attached Figure Description

[0026] Figure 1This is a perspective view of the cylindrical battery of the present invention.

[0027] Figure 2 for Figure 1 An exploded view of a cylindrical battery in the first direction.

[0028] Figure 3 for Figure 1 An exploded view of a cylindrical battery in the second direction.

[0029] Figure 4 for Figure 1 A cross-sectional perspective view of a cylindrical battery after the seal has been removed.

[0030] Figure 5 for Figure 1 A cross-sectional view of a cylindrical battery after the seal has been removed.

[0031] Figure 6 for Figure 5 A magnified view of the circled area.

[0032] Figure 7 At Figure 6 A sealing element was added to the original design.

[0033] Component conformity specifications

[0034] 100-Cylindrical battery; 10-Cell; 11-First tab; 30-Cover assembly; 31-Top cover; 311-First through hole; 313-Second through hole; 315-Explosion-proof valve; 33-Insulator; 331-Body part; 332-First extension; 333-Bending part; 334-Second extension; 335-Third through hole; 336-Fifth through hole; 337-Fourth through hole; 35-First current collector; 351-Base plate; 353-Terminal; 355-Blind hole; 357-First protrusion; 37-Sealing element; 50-Housing; 51-Fixing hole; 70-Second current collector; 71-Second protrusion; 90-Terminal Detailed Implementation

[0035] To better illustrate the purpose, technical solution, and beneficial effects of this invention, the invention will be further described below in conjunction with specific accompanying drawings. It should be noted that the following drawings are further illustrative of the invention and should not be construed as limiting it.

[0036] like Figures 1-7As shown, the cylindrical battery 100 includes a cell 10, a housing 50 housing the cell 10, and a cover assembly 30 sealing the housing 50. The cell 10 includes a first electrode, a separator, and a second electrode (not shown in the figure), with the separator located between the first and second electrodes. The first electrode includes a first film and a first tab; the first film is a first current collector coated with a first active material slurry, and the first tab is a first current collector not coated with the first active material slurry. The second electrode includes a second film and a second tab; the second film is a second current collector coated with a second active material slurry, and the second tab is a second current collector not coated with the second active material slurry. The first film, separator, and second film are stacked and wound to form a core body, with the first and second tabs protruding from opposite sides of the core body. The first and second electrodes can be formed in a conventional manner. Typically, the first electrode is the positive electrode, electrically insulated from the casing 50, and the first current collector is aluminum foil. The second electrode is the negative electrode, electrically connected to the casing 50, and the second current collector is copper foil. In the winding direction, the first and second electrodes can be complete or spaced apart; that is, the first and second electrodes can be cut into multiple pieces using uncoated first and second current collectors. If the first and second electrodes are complete, their current-carrying capacity is stronger; if they are spaced apart, the electrolyte filling performance of the battery can be improved. The first electrode is welded to the cover plate assembly 30. Before welding, the first electrode can be flattened, i.e., bent, to facilitate welding.

[0037] Furthermore, such as Figures 1-7 As shown, the cover plate assembly 30 includes a top cover plate 31, a first current collector 35, and an insulator 33. Through structural improvements, the cover plate assembly 30 eliminates the need for flexible connections, thereby shortening the current flow path, enhancing connection reliability, and avoiding melting issues at high rates, thus meeting the requirements for high-rate batteries.

[0038] The top cover plate 31 seals the housing 50 and is provided with a first through hole 311, a second through hole 313, and an explosion-proof valve 315. The first through hole 311 allows the first current collector 35 to pass through, and the two are electrically insulated. The explosion-proof valve 315 can rupture and release gas to prevent explosion when the internal gas pressure of the cylindrical battery 100 exceeds a preset value. The second through holes 313 are arranged around the first through hole 311, and there are several second through holes 313, such as 1, 2, 3, 4, etc. The number of second through holes 313 can be adjusted according to the welding strength of the through-weld joint, and the number of second through holes 313 is consistent with the number of through-weld joints. Preferably, there are 4 second through holes 313 arranged regularly around the first through hole 311. The second through holes 313 can be used to accommodate the through-weld joint, and the size of the second through holes 313 needs to be sufficient to accommodate the through-weld joint.

[0039] The first current collector 35 includes a substrate 351 and a terminal post 353 connected to the substrate 351. The substrate 351 and the terminal post 353 can be an integral structure or a separate structure. Furthermore, the substrate 351 and the terminal post 353 are an integral structure, which simplifies the assembly structure and process. The substrate 351 is soldered and fixed to one pole of the battery cell 10 (e.g., the first pole piece), and the terminal post 353 passes through and is electrically insulated from the first through hole 311. This structure integrates the conventional terminal post 353 and the first current collector 35 into one unit, simplifying the assembly structure and process. The substrate 351 has a blind hole 355 with an opening away from the battery cell 10, corresponding to the second through hole 313. The blind hole 355 and the second through hole 313 are not only corresponding in position but also in number. The solder head for through-welding can pass through the second through hole 313 and the body part 331 of the insulating member 33 in sequence to reach the blind hole 355, thus facilitating through-welding and eliminating the use of flexible connections in conventional soldering. The bottom of the blind hole 353 protrudes from the substrate 351 to form a first protrusion 357, which is connected to one pole of the battery cell 10. Since the first electrode tab 11 is flattened and bent before soldering, the distance between the bent first electrode tab 11 and the first current collector 35 increases. By providing the first protrusion 357, the disadvantage caused by this increased distance can be compensated. The close contact between the first protrusion 357 and the bent first electrode tab 11 facilitates through-welding. Therefore, through-welding allows the first electrode tab 11 to be bent and welded to the first protrusion 357.

[0040] An insulating member 33 is located between the top cover plate 31 and the first current collector plate 35. The insulating member 33 includes a body portion 331, a first extension portion 332, a bent portion 333, and a second extension portion 334. The body portion 331 extends towards the top cover plate 31 to form the first extension portion 332, and extends away from the top cover plate 31 to form the second extension portion 334. The body portion 331 is located between the substrate 351 and the top cover plate 31 to electrically insulate the substrate 351 and the top cover plate 31, and has a fourth through hole 337 for the electrode post 353 to pass through. The first extension portion 332 is located between the electrode post 353 and the top cover plate 31 to electrically insulate the electrode post 353 and the top cover plate 31, and has a fifth through hole 336 for the electrode post 353 to pass through. The second extension portion 334 is located between the substrate 351 and the housing 50 to electrically insulate the substrate 351 and the housing 50. The bent portion 333 is located at the end of the first extension 332 away from the main body 331. The bent portion 333 and the first extension 332 enclose a space that can be engaged with the top cover 31. The bent portion 333 and the pole post 353 can also be engaged. Specifically, the top of the pole post 353 can extend outward and engage with the bent portion 333. The main body 331, the first extension 332, the bent portion 333, and the second extension 334 can be injection molded, which not only serves as insulation but also as sealing. The main body 331 has a third through hole 335 corresponding to the second through hole 313. The two are not only corresponding in position but also in number. Therefore, the welding head for penetration welding can pass through the second through hole 313 and the third through hole 335 in sequence to reach the blind hole 355, thereby facilitating penetration welding.

[0041] In addition, to prevent electrolyte from flowing into the second through hole 313 during injection or external dust from falling into the second through hole 313 and causing unnecessary hazards, the second through hole 313 can be sealed after penetration welding. Figures 1-3 As shown, a sealing element 37 is provided inside the second through hole 313. The sealing element 37 can be obtained by injecting glue or by using a sealing pin, or other methods, as long as it can ensure that the second through hole 313 is sealed after penetration welding without affecting the welding performance. The sealing element 37 extends at least into the third through hole 335. Sealing the second through hole 313 after penetration welding can prevent electrolyte leakage. The absence of gaps between the battery cell 10 and the top cover plate 31 can also prevent the battery cell 10 from moving up and down within the housing 50, ensuring that the weld joint of the penetration weld does not loosen.

[0042] Furthermore, such as Figures 5-7As shown, a second current collector 70 is provided between the battery cell 10 and the casing 50. The second current collector 70 has several second protrusions 71 protruding from it in the direction facing the battery cell 10. The number of second protrusions 71 can be multiple, such as 1, 2, 3, 4, etc. Each second protrusion 71 can be a single annular structure or a non-annular structure. The number and size of the second protrusions 71 can be adjusted according to the required current carrying capacity of the battery. A second electrode tab is bent and welded to the second protrusion 71. Both can be done using through-welding, with the welding points corresponding to the second protrusion 71. One side of the second current collector 70 is welded to the second electrode tab, and the other side can be welded to a terminal 90 to achieve external power output. A fixing hole 51 can be provided at the bottom of the casing 50. The terminal 90 passes through and is fixed to the fixing hole 51 and welded to the second protrusion 71. Of course, the second current collector 70, the bottom of the casing 50, and the terminal 90 can also have other structures, as long as they can meet the output requirements of the negative terminal.

[0043] The assembly process of the cylindrical battery 100 of the present invention may include the following steps: (1) assembling the top cover plate 31, the first current collector plate 35 and the insulating component 33 into a cover plate assembly 30; (2) placing the battery cell 10 in the housing 50; (3) welding the housing 50 and the top cover plate 31; (4) passing the through-welding head through the second through hole 313 and the third through hole 335, and welding the substrate 351 and the tab of one electrode in the battery cell 10; (5) injecting sealant into the second through hole 313 by potting glue or sealing it with a sealing nail; (6) performing through-welding on the tab of the other electrode in the battery cell 10 and the bottom of the housing 50.

[0044] In step (1), the top cover plate 31, the first current collector plate 35, and the insulating component 33 are assembled into a cover plate assembly 30. The top cover plate 31 and the first current collector plate 35 can be fixed in place, and then the insulating component 33 can be formed using injection molding to assemble the cover plate assembly 30. Alternatively, a pre-formed insulating component 33 can be used, and the first current collector plate 35, the insulating component 33, and the top cover plate 31 can be assembled sequentially. If the substrate 351 and the terminal post 353 in the first current collector plate 35 are integrated, the substrate 351 can be snapped into the lower part of the insulating component 33, and the terminal post 353 can be passed through the fifth through hole 336 and the fourth through hole 337 in the insulating component 33 before assembling the top cover plate. If the insulating component 33 is formed using injection molding, the first current collector plate 35 and the top cover plate 33 are spaced apart and fixed separately, and then the insulating component 33 is formed using injection molding. If the substrate 351 and the terminal post 353 in the first current collector 35 are separate, the substrate 351 and the terminal post 353 are first welded and fixed, and then assembled into the cover plate assembly 30 according to the above process.

[0045] In addition, when the sealant is injected by potting or the second through hole 313 is sealed by sealing pins, the sealant or sealing pins not only seal the entire through hole 313, but also extend into the third through hole 335, that is, occupy part of the space of the third through hole 335. In this way, the lack of gaps between the core 10 and the top cover plate 31 can be avoided to prevent the core 10 from moving up and down in the housing 50. Furthermore, the order of step (5) injecting sealant into the second through hole 313 by potting or sealing pins and step (6) performing through welding between the tab of the other pole of the core 10 and the bottom of the housing 50 can be replaced. That is, the tab of the other pole of the core 10 and the bottom of the housing 50 can be through welded first, and then the second through hole 313 can be sealed.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, it is not limited to those listed in the embodiments. Those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A cylindrical battery, characterized in that, The device includes a battery cell, a housing containing the battery cell, and a cover plate assembly that seals the housing. The cover plate assembly includes a top cover plate, a first current collector plate, and an insulating member. The insulating member is located between the top cover plate and the first current collector plate. The top cover plate seals the housing and has a first through hole. The first current collector plate includes a substrate and a terminal post connected to the substrate. The substrate is welded and fixed to a terminal lug of one electrode in the battery cell. The terminal post passes through and is electrically insulated from the first through hole. The top cover plate has a plurality of second through holes around the first through hole. A sealing member is provided in each of the second through holes. The insulating member has a third through hole corresponding to each of the second through holes.

2. The cylindrical battery according to claim 1, characterized in that, The insulating component includes a body portion and a first extension portion formed by extending the body portion toward the top cover plate. The body portion is located between the substrate and the top cover plate and has a fourth through hole for the electrode post to pass through. The first extension portion is located between the electrode post and the top cover plate and has a fifth through hole for the electrode post to pass through. The body portion has the third through hole.

3. The cylindrical battery according to claim 2, characterized in that, The insulating member further includes a second extension formed by the body portion extending away from the top cover sheet, the second extension being located between the substrate and the housing.

4. The cylindrical battery according to claim 2, characterized in that, The insulating component further includes a bent portion located at the end of the first extension away from the body portion, and the bent portion and the first extension portion together form a space that can be snapped onto the top cover sheet.

5. The cylindrical battery according to claim 1, characterized in that, The seal extends at least into the third through hole.

6. The cylindrical battery according to claim 1, characterized in that, The substrate has a blind hole with an opening away from the battery cell corresponding to the second through hole.

7. The cylindrical battery according to claim 6, characterized in that, The bottom of the blind hole protrudes from the substrate to form a first protrusion, and the first protrusion is connected to one of the electrodes in the battery cell.

8. The cylindrical battery according to claim 7, characterized in that, The battery cell includes a first electrode, a separator, and a second electrode. The separator is located between the first electrode and the second electrode. The first electrode includes a first diaphragm and a first tab. The second electrode includes a second diaphragm and a second tab. The first diaphragm, the separator, and the second diaphragm are stacked and wound to form a core body. The first tab and the second tab are respectively protruding on opposite sides of the core body. The first tab is bent and welded to the first protrusion.

9. The cylindrical battery according to claim 8, characterized in that, A second current collector is provided between the battery cell and the housing. The second current collector has several second protrusions protruding in the direction facing the battery cell. The second electrode tab is bent and welded to the second protrusions.

10. The assembly process of the cylindrical battery according to any one of claims 1 to 9, characterized in that, Including the following steps: (1) Assemble the top cover plate, the first current collector and the insulating component into the cover plate assembly; (2) The battery cell is housed in the housing; (3) Weld the housing and the top cover plate together; (4) Pass the through-hole welding head through the second through hole and the third through hole, and weld the substrate and the electrode tab of one electrode in the cell; (5) Seal the second through hole by injecting sealant or by using a sealing pin; (6) The tab of the other pole in the cell and the bottom of the casing are welded together.

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