Battery end cover structure and cylindrical battery

Abstract

The present disclosure relates to the technical field of cylindrical battery, and particularly relates to a battery end cover structure and a cylindrical battery. The structure comprises a busbar, a connecting sheet, an end cover and a pole assembly. The connecting sheet is arranged on the busbar in a superposed manner, the edge of the connecting sheet is connected with the edge of the busbar, and a set connecting width is arranged between the connecting sheet and the busbar. The pole assembly is arranged in the middle of the end cover and is sealingly connected with the end cover. The side of the connecting sheet away from the busbar is connected with the end of the pole assembly. In the technical scheme of the present disclosure, the connecting (welding) area between the busbar, the core tab and the pole is large, the overcurrent capacity of the connecting position is enhanced, the required overcurrent capacity can be achieved by adjusting the welding area width of the connecting sheet, the busbar, the pole assembly and the end cover are connected into a structural member by the connecting sheet, the structural member can be directly detected, and the qualified rate of the battery end cover structure is improved.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of cylindrical battery, in particular to a battery end cover structure and a cylindrical battery. BACKGROUND

[0002] With the continuous development of new energy technology field, as the core component of new energy vehicles, power battery has been widely developed. Among them, the power battery control system is one of the key components of new energy vehicles, and its main function is to control the charging and discharging process of the battery, and to ensure the safety and life of the battery.

[0003] The cylindrical battery is a common type of battery, which includes a shell, a winding core, a bus bar, an end cover and a pole, etc. At present, the positive bus bar and the top cover are welded to form an upper cover in the cylindrical battery. Due to the heating of the positive bus bar during welding, the bus bar will deform. The deformed positive bus bar is welded with the positive tab of the battery cell. The top cover outer welding ring is welded with the shell for sealing. The negative bus bar is welded with the negative tab. The negative bus bar is welded with the shell. The shell is sealed and welded with the bottom cover. The sealing nail is sealed and welded with the bottom cover to complete the battery structure design.

[0004] However, in the existing cylindrical battery, the welding area between the positive bus bar or the negative bus bar and the winding core and the welding area between the bus bar and the pole are relatively small, which reduces the overcurrent capacity of the cylindrical battery after welding and affects the performance of the cylindrical battery. SUMMARY

[0005] To solve at least the above technical problems in the prior art, the present disclosure provides a battery end cover structure and a cylindrical battery.

[0006] In one aspect, the present disclosure provides a battery end cover structure, which comprises a bus bar, a connecting piece, an end cover and a pole assembly. The connecting piece is arranged on the bus bar. The edge of the connecting piece is connected with the edge of the bus bar, and the connecting piece and the bus bar have a set connection width. The pole assembly is arranged in the middle of the end cover and is sealed and connected with the end cover. The side of the connecting piece away from the bus bar is connected with the end of the pole assembly.

[0007] In some embodiments, the pole assembly comprises an inner pole and an outer pole. The middle of the outer pole is provided with a through hole, and the inner pole is arranged in the through hole and is fixedly connected with the outer pole. The end of the inner pole is connected with the connecting piece, and the outer wall of the outer pole is sealed and connected with the end cover.

[0008] In some embodiments, the inner pole post is in a columnar shape, the first end of the inner pole post is a flat surface, and a middle portion of the second end is provided with a plug-in protrusion; a middle portion of the connecting sheet is provided with a through hole, the plug-in protrusion is arranged in the through hole, and the second end of the inner pole post is in abutment with the connecting sheet.

[0009] In some embodiments, the outer pole post comprises a sleeve structure, an end portion of an outer wall of the sleeve structure is provided with an annular protrusion, and a bottom portion of the outer wall of the sleeve structure is provided with a press-in rivet bending portion; a middle portion of the end cover is sleeved on the sleeve structure and located between the annular protrusion and the press-in rivet bending portion, and the end cover and the sleeve structure are sealingly connected through a sealing structure.

[0010] In some embodiments, the sealing structure comprises an outer insulation ring and a sealing ring; the outer insulation ring comprises a first insulation portion and a second insulation portion, the first insulation portion is sleeved on the outer wall of the sleeve structure, and the second insulation portion is attached to a side of the annular protrusion facing the press-in rivet bending portion; the sealing ring is sleeved outside the first insulation portion, the end cover is located between the sealing ring and the second insulation portion, and the press-in rivet bending portion extrudes the sealing ring to generate deformation.

[0011] In some embodiments, an annular stop ring is arranged on an inner wall of the sleeve structure at an end portion, the first end of the inner pole post is provided with an annular platform for abutting against the annular stop ring; and the first end of the inner pole post is fixedly connected with the end portion of the sleeve structure.

[0012] In some embodiments, the connecting sheet is provided with a reinforcing rib; or the connecting sheet is provided with a reinforcing rib in an annular shape, and a center of the reinforcing rib coincides with a center of the connecting sheet.

[0013] In some embodiments, the end cover is provided with a notch; and / or the end cover is provided with an annular groove, and a center of the annular groove coincides with a center of the end cover.

[0014] Another aspect of the present disclosure also provides a cylindrical battery comprising the battery end cover structure.

[0015] In some embodiments, a housing is further included, and a winding core is arranged in the housing; the battery end cover structure comprises a positive battery end cover structure and a negative battery end cover structure, and edges of the end cover in the positive battery end cover structure and the negative battery end cover structure are respectively connected with end portions of the housing.

[0016] The battery end cover structure and the cylindrical battery provided by the present disclosure are characterized in that one side of the bus bar is connected with the pole column assembly through the connecting piece, and the other side is connected with the pole lug of the cylindrical battery roll core, wherein a set connection width is arranged between the bus bar and the connecting piece, and the connection structure realizes the connection conduction between the connecting piece and the bus bar. In the technical scheme of the present disclosure, the connection (welding) area between the bus bar and the pole lug of the roll core and the pole column is large, the overcurrent capacity of the connection position is enhanced, the required overcurrent capacity can be achieved by adjusting the welding area width of the connecting piece, and the bus bar, the pole column assembly and the end cover are connected into one structural member through the connecting piece, the structural member can be directly detected, and thus the qualified rate of the battery end cover structure is improved. BRIEF DESCRIPTION OF DRAWINGS

[0017] The above and other objects, features and advantages of the exemplary embodiments of the present disclosure will be more apparent from the following detailed description read in conjunction with the accompanying drawings, in which:

[0018] In the drawings, identical or corresponding reference signs refer to identical or corresponding parts.

[0019] Figure 1 A sectional view of the battery end cover structure provided by the embodiment of the present disclosure;

[0020] Figure 2 A sectional view of the pole column assembly in the battery end cover structure provided by the embodiment of the present disclosure;

[0021] Figure 3 A local enlarged view of the sealing connection of the end cover in the battery end cover structure provided by the embodiment of the present disclosure Figure 1 ;

[0022] Figure 4 A local enlarged view of the sealing connection of the end cover in the battery end cover structure provided by the embodiment of the present disclosure Figure 2 ;

[0023] Figure 5 A sectional view of the connecting piece in the battery end cover structure provided by the embodiment of the present disclosure;

[0024] Figure 6 A structural schematic view of the end cover in the battery end cover structure provided by the embodiment of the present disclosure;

[0025] Figure 7 A sectional view of the cylindrical battery provided by the embodiment of the present disclosure.

[0026] In the drawings:

[0027] 1: end cover; 2: pole column assembly; 3: outer insulating ring; 4: sealing ring; 5: bus bar; 6: connecting piece; 7: shell; 8: roll core;

[0028] 11: Scratches; 12: Annular grooves;

[0029] 21: Outer pole; 22: Inner pole; 211: Sleeve structure; 212: Annular protrusion; 213: Press-fit bent part; 221: Insertion protrusion;

[0030] 31: First insulating part; 32: Second insulating part;

[0031] 61: Reinforcing rib. Detailed Implementation

[0032] To make the objectives, features, and advantages of this disclosure more apparent and understandable, the technical solutions in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0033] This disclosure provides a battery end cap structure, including a busbar, a connecting piece, an end cap, and a terminal assembly; the busbar is used to connect to the tab of the battery core and to the connecting piece, wherein the connecting piece is also connected to the terminal assembly, and overcurrent is transmitted to the terminal assembly via the busbar and the connecting piece.

[0034] The following description, in conjunction with the accompanying drawings, explains the components of the battery end cap structure and the connections between them.

[0035] In this embodiment of the disclosure, such as Figures 1 to 6 As shown, the connecting piece 6 and the busbar 5 are stacked, with the edge of the connecting piece 6 connected to the edge of the busbar 5, and a set connection width between them. To maximize the welding area between the busbar 5 and the core 8, the connecting piece 6 is first welded to the terminal assembly 2 to form a structure, and welding inspection is performed. Because it is separated from the core 8, the risk of damaging the battery cell during inspection is reduced. After the busbar 5 and the core 8 are welded, the connecting piece 6 is then welded to the busbar 5. A contour welding position can be made on the connecting piece 6, that is, the edge of the connecting piece 6 is welded to the edge of the busbar 5, and this welding position can have a certain welding width, extending inward from the edge welding position. By adjusting the position of the contour welding position, the overcurrent requirements can be met.

[0036] For example, a raised edge is arranged at the edge of the busbar 5, and the edge of the connecting piece 6 abuts against the inner wall of the raised edge and is welded with the raised edge. The connection width set can be explained as follows: according to the design of the overcurrent size, a certain width is welded inward from the welding position of the edges of the busbar 5 and the connecting piece 6, and the welding structure of the width realizes the conduction between the busbar 5 and the connecting piece 6.

[0037] In the embodiment of the present disclosure, the pole assembly 2 is arranged in the middle of the end cover 1 and is sealingly connected with the end cover 1. The middle of the end cover 1 is sealingly connected with the pole assembly 2, and the edge of the end cover 1 is sealingly connected with the end of the cylindrical battery shell 7. The sealing connection between the end cover 1 and the pole assembly 2 is described below. The side of the connecting piece 6 away from the busbar 5 is connected with the end of the pole assembly 2 to realize the conduction between the connecting piece 6 and the pole assembly 2. The connection area between the end of the pole assembly 2 and the connecting piece 6 can be adjusted.

[0038] For example, as shown in FIGS. 1 and 2, the end cover 1 is sealingly connected with the pole assembly 2. Figure 1 Figure 2 In the embodiment of the present disclosure, the pole assembly 2 includes an inner pole 22 and an outer pole 21. The middle of the outer pole 21 is provided with a through hole, and the inner pole 22 is arranged in the through hole and fixedly connected with the outer pole 21. The end of the inner pole 22 is connected with the connecting piece 6, and the outer wall of the outer pole 21 is sealingly connected with the end cover 1. The pole assembly 2 is divided into two parts and can be assembled by the inner pole 22 and the outer pole 21. Specifically,

[0039] The inner pole 22 is in a columnar shape. The first end of the inner pole 22 is a flat surface, and the middle of the second end is provided with a plug-in protrusion 221. The middle of the connecting piece 6 is provided with a through hole, and the plug-in protrusion 221 is arranged in the through hole. The second end of the inner pole 22 abuts against the connecting piece 6.

[0040] The outer pole 21 includes a sleeve structure 211. The end of the outer wall of the sleeve structure 211 is provided with an annular protrusion 212, and the bottom of the outer wall of the sleeve structure 211 is provided with a press-in rivet bending part 213. The middle of the end cover 1 is sleeved on the sleeve structure 211 and located between the annular protrusion 212 and the press-in rivet bending part 213. The end cover 1 is sealingly connected with the sleeve structure 211 through a sealing structure.

[0041] Therefore, the end of the inner pole 22 (except the plug-in protrusion 221 part) abuts against and is welded with the connecting piece 6. The size of the overcurrent between the connecting piece 6 and the pole assembly 2 can be adjusted by controlling the size of the part. The split structure of the inner pole 22 and the outer pole 21 can flexibly adjust the size of the pole to achieve the actual application effect.

[0042] ​For example, the inner wall of the sleeve structure 211 is provided with an annular stop ring (not shown in the figure) at the end, and the first end of the inner pole column 22 is provided with an annular platform (not shown in the figure) for abutting against the annular stop ring; the first end of the inner pole column 22 is fixedly connected with the end of the sleeve structure 211. By arranging the annular stop ring and the annular platform structure, a limiting structure can be arranged in the axial direction of the inner pole column 22. When the two are assembled, the annular platform is abutted against the annular stop ring, and welding connection is performed. In this way, the overcurrent capacity and welding strength of the outer welded flow guide can be improved. After a plurality of single batteries form a battery pack, the connection piece 6 needs to be welded to the battery pole column end for flow guiding. The effective area of the welding determines the overcurrent capacity. The larger the welding area, the stronger the overcurrent capacity. The end surface of the positive / negative pole column assembly 2 can be reasonably designed according to actual needs.

[0043] In the embodiment of the present disclosure, the liquid injection hole for the cylindrical battery can be arranged on the inner pole column 22 of the positive electrode or on the inner pole column 22 of the negative electrode.

[0044] As shown in Figure 3 In the embodiment of the present disclosure, the sealing structure includes an outer insulating ring 3 and a sealing ring 4; the outer insulating ring 3 includes a first insulating part 31 and a second insulating part 32, the first insulating part 31 is sleeved on the outer wall of the sleeve structure 211, and the second insulating part 32 is attached to the side of the annular protrusion 212 facing the press-in bending part 213; the sealing ring 4 is sleeved outside the first insulating part 31, the end cover 1 is located between the sealing ring 4 and the second insulating part 32, and the press-in bending part 213 extrudes the sealing ring 4 to generate deformation.

[0045] The outer pole column 21 is sleeve-shaped, and the press-in bending part 213 at the bottom thereof is formed through a press-in process, that is, positioning is performed at the upper end of the pole column assembly 2, and press-in is performed at the lower end position. During the press-in process, pressure is generated to make the sealing ring 4 deform to achieve a sealing effect. The inner pole column 22 is fit in position through a gap and is welded.

[0046] As shown in Figure 4 For the sealing method of the end cover 1 and the pole column assembly 2 in the cylindrical battery, the pole column (not divided into the inner pole column 22 and the outer pole column 21 in the figure) is welded with the connection piece 6, the side of the pole column away from the connection piece 6 is attached to the end cover 1, and laser welding is used to perform penetrating sealing welding of the pole column and the end cover 1 to achieve a sealing effect. The diameter of the pole column is smaller than the opening diameter of the end cover 1. The diameter of the pole column and the opening diameter of the end cover 1 can be flexibly designed according to actual needs to achieve the effect of actual application.

[0047] As shown in Figure 5 In the embodiment of the present disclosure, the connection piece 6 is provided with a reinforcing rib 61; or the connection piece 6 is provided with a reinforcing rib 61 in the form of a ring, and the center of the reinforcing rib 61 coincides with the center of the connection piece 6.

[0048] By setting the reinforcing rib 61, the heat dissipation surface during welding is larger, the risk of deformation during welding is reduced, and the situation that the deformation of the connecting piece 6 easily causes the welding fit part to form a virtual welding and a burst point is reduced.

[0049] As shown in Figure 6 The present embodiment provides a cylindrical battery end cover structure, as shown in

[0050] The present embodiment also provides a cylindrical battery, which comprises the above battery end cover structure and a shell 7, and the shell 7 is provided with a winding core 8; the battery end cover structure comprises a positive electrode battery end cover structure and a negative electrode battery end cover structure, and the edges of the end cover 1 in the positive electrode battery end cover structure and the negative electrode battery end cover structure are respectively connected with the end part of the shell 7.

[0051] As shown in Figure 7 The cylindrical battery comprises a positive electrode battery end cover structure, a shell 7, a winding core 8 and a negative electrode battery end cover structure. Among them, the positive electrode battery end cover structure and the negative electrode battery end cover structure are the battery end cover structures as shown in Figures 1 to 6

[0052] The assembled positive electrode battery end cover structure and the negative electrode battery end cover structure are subjected to sealing detection by a detection device, and after passing the detection, they are used as the structural parts of the battery. Among them, in the positive electrode battery end cover structure, the connecting piece 6 and the inner pole 22 are penetrated or lap welded at position A, and the formed structural part is subjected to flatness and appearance detection. The positive and negative electrode ears of the winding core 8 are flattened, the bus bar 5 of the positive electrode battery end cover structure is welded with the winding core 8 at position B, the bus bar 5 of the positive electrode battery end cover structure is designed in a special shape and flexibility, and is welded with the connecting piece 6 at position C through 360 rotation of the battery core. The welding position of the connecting piece 6 and the bus bar 5 can be designed differently according to actual needs. After welding, the battery core assembly is subjected to air tightness detection by a detection device, and the battery core assembly that passes the detection is put into the shell 7. After being put into the shell 7, it is welded with the shell 7 at position E through 360 rotation, and then subjected to welding detection by a detection device.

[0053] ​The connecting piece 6 of the negative electrode battery end cover structure is penetrated or lap welded with the inner pole column 22 of the negative electrode battery end cover structure at position F. The planeness and appearance of the formed structure are detected. The bus bar 5 of the negative electrode battery end cover structure is designed in a special flexible manner. The bus bar 5 and the connecting piece 6 are welded through the rotation of the battery cell 360 at position G. The welding position of the connecting piece 6 and the bus bar 5 can be designed differently according to actual requirements. The inner pole column 22 and the outer pole column 21 of the negative electrode battery end cover structure are welded through the rotation of the battery cell 360 at position H after welding. The air tightness of the battery cell assembly is detected by a detection device after welding. The sealing welding between the battery cell assembly and the shell 7 is performed at position I after the detection is qualified. The welding position is designed in a lap joint manner to facilitate the welding between the end cover 1 and the shell 7. The sealing property is detected by a detection device after welding. The battery cell is filled with electrolyte after the detection is qualified. The sealing nail is welded at position J after the electrolyte is filled. The sealing property is detected after welding.

[0054] The battery end cover structure and the cylindrical battery provided by the present disclosure are characterized in that one side of the bus bar 5 is connected with the pole column assembly 2 through the connecting piece 6, and the other side is connected with the tab of the cylindrical battery roll core 8. There is a protruding structure with a set width between the bus bar 5 and the connecting piece 6, which realizes the connection and conduction between the connecting piece 6 and the bus bar 5. In the technical solution of the present disclosure, the connection (welding) area between the bus bar 5, the tab of the roll core 8 and the pole column is large, which enhances the overcurrent capacity of the connection position, and the required overcurrent capacity can be achieved by adjusting the width of the welding area of the connecting piece 6. The bus bar 5, the pole column assembly 2 and the end cover 1 are connected into one structure through the connecting piece 6, and the structure can be directly detected, thereby improving the qualified rate of the battery end cover structure.

[0055] In the description of the present disclosure, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example" or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present disclosure. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the different embodiments or examples described in the present disclosure and the features of the different embodiments or examples can be combined and combined by those skilled in the art without contradiction.

[0056] In addition, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present disclosure, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0057] The above merely describes specific embodiments of the present disclosure, but the protection scope of the present disclosure is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present disclosure, which should be covered within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the protection scope of the claims.

Claims

1. A cylindrical battery, characterized in that, It includes a positive electrode battery end cap structure, a negative electrode battery end cap structure, and a housing (7), wherein a core (8) is provided inside the housing (7). Both the positive electrode battery end cap structure and the negative electrode battery end cap structure include a busbar (5), a connecting piece (6), an end cap (1), and an electrode post assembly (2). The connecting piece (6) is stacked on top of the busbar (5), the edge of the connecting piece (6) is connected to the edge of the busbar (5), and there is a set connection width between the connecting piece (6) and the busbar (5); The pole assembly (2) passes through the middle of the end cap (1) and is sealed to the end cap (1). The connecting piece (6) is connected to the end of the pole assembly (2) on the side away from the busbar (5). The edges of the end caps (1) in the positive electrode battery end cap structure and the negative electrode battery end cap structure are respectively connected to the ends of the housing (7); During the manufacturing process, the connecting piece (6) is first welded to the pole assembly (2) to form a structure and the welding is inspected. Then the busbar (5) is welded to the core (8) and the connecting piece (6) is welded to the busbar (5). The defined connection width is explained as follows: based on the design of the overcurrent size, a certain width is welded inward from the edge welding position of the busbar (5) and the connecting piece (6), and the welding structure of this width realizes the conduction between the busbar (5) and the connecting piece (6).

2. The cylindrical battery according to claim 1, characterized in that, The pole assembly (2) includes an outer pole (21) and an inner pole (22). The outer pole (21) has a through hole in the middle. The inner pole (22) passes through the through hole and is fixedly connected to the outer pole (21). The end of the inner pole (22) is connected to the connecting piece (6), and the outer wall of the outer pole (21) is sealed to the end cap (1).

3. The cylindrical battery according to claim 2, characterized in that, The inner pole post (22) is columnar, with the first end of the inner pole post (22) being a plane and the middle of the second end having an insertion protrusion (221). The connecting piece (6) has a through hole in the middle, the insertion protrusion (221) is located in the through hole, and the second end of the inner pole (22) abuts against the connecting piece (6).

4. The cylindrical battery according to claim 2, characterized in that, The outer pole post (21) includes a sleeve structure (211), the end of the outer wall of the sleeve structure (211) is provided with an annular protrusion (212), and the bottom of the outer wall of the sleeve structure (211) is provided with a press-fit bent part (213). The end cap (1) is fitted onto the sleeve structure (211) at its middle part and is located between the annular protrusion (212) and the press-fit bent part (213). The end cap (1) and the sleeve structure (211) are sealed together by a sealing structure.

5. The cylindrical battery according to claim 4, characterized in that, The sealing structure includes an outer insulating ring (3) and a sealing ring (4); The outer insulating ring (3) includes a first insulating part (31) and a second insulating part (32). The first insulating part (31) is sleeved on the outer wall of the sleeve structure (211), and the second insulating part (32) is attached to the side of the annular protrusion (212) facing the press-fit bent part (213). The sealing ring (4) is fitted over the first insulating part (31), the end cap (1) is located between the sealing ring (4) and the second insulating part (32), and the press-fit bending part (213) squeezes the sealing ring (4) to produce deformation.

6. The cylindrical battery according to claim 4, characterized in that, The inner wall of the sleeve structure (211) is provided with an annular retaining ring at the end, and the first end of the inner pole post (22) is provided with an annular platform for abutting against the annular retaining ring. The first end of the inner pole post (22) is fixedly connected to the end of the sleeve structure (211).

7. The cylindrical battery according to any one of claims 2 to 6, characterized in that, The connecting piece (6) is provided with reinforcing ribs (61).

8. The cylindrical battery according to any one of claims 2 to 6, characterized in that, The end cap (1) is provided with a notch (11); and / or The end cap (1) is provided with an annular groove (12), the center of which coincides with the center of the end cap (1).

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