Cylindrical battery arrangement and battery device

Abstract

Cylindrical battery assembly, characterized in that the cylindrical battery assembly comprises a cylindrical battery (200) and a busbar (300), the cylindrical battery (200) comprises a housing (202) and a terminal post (201), the terminal post (201) is arranged on an end surface (202a) of the housing (202), a wall thickness of the housing (202) in an axial direction of the cylindrical battery is less than a thickness of the terminal post (201), the busbar (300) comprises a terminal post connecting portion (301) electrically connected to the side of the terminal post (201) facing away from the housing (202), and a housing connecting portion (302) electrically connected to the housing (202), wherein a ratio A of a thickness of the terminal post connecting portion (301) to a thickness of the housing connecting portion (302) in the range of 0.5≤A≤0.9.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of battery technology and, in particular, to a cylindrical battery assembly and a battery pack. BACKGROUND

[0002] A cylindrical battery assembly consists of cylindrical batteries, each with two output terminals of opposite polarity at one axial end. One output terminal is a terminal post, and the other output terminal is the cylindrical battery case. These two output terminals are welded to the same busbar, resulting in unbalanced connection strength, making the connection between the output terminal with the weaker connection strength and the busbar a weak point prone to failure.

[0003] In view of this, a technical problem that must be solved by the specialist is how to balance the connection strength between the two output terminals and the busbar. SUMMARY

[0004] To solve the above technical problem, the present application provides a cylindrical battery assembly. The cylindrical battery assembly includes a cylindrical battery and a bus bar. The cylindrical battery includes a case and a terminal post. The terminal post is disposed on an end surface of the case. A wall thickness of the case in an axial direction is smaller than a thickness of the terminal post of the cylindrical battery. The bus bar includes a terminal post connecting portion electrically connected to the side of the terminal post facing away from the case, and a case connecting portion electrically connected to the case. A ratio A of a thickness of the terminal post connecting portion to a thickness of the case connecting portion is 0.5≤A≤0.9.

[0005] The cylindrical battery assembly provided by the present application can ensure the balance between the connection strength of the terminal post to the bus bar and the connection strength of the case to the bus bar by controlling the ratio A of the thickness of the terminal post connecting portion to the thickness of the case connecting portion within the range of 0.5-0.9, while ensuring the current-carrying capacity on the terminal post side and preventing deformation of the case during the electrical connection process between the case and the case connecting portion.If A is too large, the housing connecting section would be thin and the terminal post connecting section would be thick, resulting in weak connection strength between the housing connecting section and the housing, but strong connection strength between the terminal post connecting section and the terminal post, making the connection point between the housing connecting section and the housing a weak point prone to failure. If A is too small, the terminal post connecting section would be thin and the housing connecting section would be thick, resulting in weak connection strength between the terminal post connecting section and the terminal post, but strong connection strength between the housing connecting section and the housing, making the connection point between the terminal post connecting section and the terminal post a weak point prone to failure.In addition, the thin terminal post connection portion would result in poor current carrying capacity on the terminal post side, and since the wall thickness of the case in an axial direction of the cylindrical battery is thinner than the thickness of the terminal post, the thick case connection portion would easily cause case deformation when connected to the case.

[0006] The battery device provided by the present application also has the above technical effects because it includes the above cylindrical battery assembly. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a plan view of a partial structure of a battery device according to an embodiment of the present application; Fig. 2 is a perspective substructure in Fig. 1; Fig. 3 is a perspective substructure in Fig. 2; Fig. 4 is an exploded view of Fig. 3; Fig. 5 is a perspective view of a single busbar; Fig. 6 is a plan view of Fig. 5; and Fig. 7 is a perspective view of a connecting rail.

[0007] The reference numerals are as follows: 100 housing, 101 base plate; 200 cylindrical battery, 201 terminal post, 202 housing, 202a end face of the housing, 203 annular insulating element; 300 busbar, 301 terminal post connecting section, 302 housing connecting section, 303 transition section, 3031 first transition section, 3032 second transition section, a first step, b second step, c recess, d fixing hole; 400 insulation plate, 401 free area, 402 connection post. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0008] The present application provides a cylindrical battery assembly and a battery device. To provide those skilled in the art with a better understanding of the technical solution of the present application, a detailed description is provided below in conjunction with the drawings and specific embodiments.

[0009] As in Fig. As shown in Figure 1, the battery device provided by the present application includes a housing 100 and at least two cylindrical battery assemblies located within the housing 100. The housing 100 includes a base plate 101. The cylindrical battery assembly includes a cylindrical battery (or cylindrical batteries) 200.

[0010] In some embodiments, the axial direction of the cylindrical battery 200 is parallel to the base plate 101, as shown in the illustrated embodiment.

[0011] In some embodiments, the axial direction of the cylindrical battery 200 is perpendicular to the base plate 101.

[0012] In particular, as in Fig. 1, eight cylindrical battery assemblies are arranged, with two assemblies being arranged in a row, thereby forming four rows arranged one behind the other in a first direction. The two cylindrical battery assemblies in the same row are stacked in a direction perpendicular to the base plate 101. Each cylindrical battery assembly includes a plurality of cylindrical batteries 200, the axial direction of each cylindrical battery 200 in each assembly being along the first direction, and the cylindrical batteries 200 in each assembly being arranged sequentially in a second direction. The first direction and the second direction are perpendicular to each other and both parallel to the base plate 101. In practice, the number of rows of cylindrical battery assemblies may be less than or greater than four rows.The number of stacked layers of cylindrical battery arrays in each row may also be more than two.

[0013] As in Fig. 2, the cylindrical battery assembly also includes a bus bar 300. The bus bar 300 includes a terminal post connecting portion 301 and a case connecting portion 302.

[0014] As in Fig. As shown in Fig. 4, the cylindrical battery 200 includes a casing 202 and a terminal post 201. The terminal post 201 is disposed on an end surface 202a of the casing 202, and the terminal post 201 and the casing 202 are insulated by an annular insulating member 203 surrounding the outer periphery of the terminal post 201. The wall thickness of the casing 202 is smaller than the thickness of the terminal post 201 in the axial direction of the cylindrical battery. One of the casing 202 and the terminal post 201 serves as the positive output terminal of the cylindrical battery 200, and the other as the negative output terminal.For example, if the material of the housing 202 includes steel, the housing 202 may serve as the negative output terminal and the terminal post 201 may serve as the positive output terminal; if the material of the housing 202 includes aluminum, such as aluminum alloy material or pure aluminum material, the terminal post 201 may serve as the negative output terminal and the housing 202 may serve as the positive output terminal, in which case the positive tab of the cell within the housing 202 is electrically connected to the housing 202 and the negative tab of the cell is electrically connected to the terminal post 201.

[0015] As in Fig. 3, the terminal post connecting portion 301 of the same bus bar 300 is electrically connected to a side of the terminal post 201 of a cylindrical battery 200 remote from the case 202, and the case connecting portion 302 is electrically connected to the case 202 of an adjacent cylindrical battery 200.

[0016] A ratio A is defined as the ratio of the thickness of the terminal post connecting portion 301 to the thickness of the case connecting portion 302, that is, A is equal to the thickness of the terminal post connecting portion 301 divided by the thickness of the case connecting portion 302. Here, the thickness of the terminal post connecting portion 301 and the thickness of the case connecting portion 302 refer to their dimensions in the axial direction of the cylindrical battery. The range of A is: 0.5≤A≤0.9, for example, A can be 0.5, 0.6, 0.7, 0.8, or 0.9.

[0017] If A is too large, the housing connecting portion 302 would be thin and the terminal post connecting portion 301 would be thick, resulting in a weak connection strength between the housing connecting portion 302 and the housing 202, but a strong connection strength between the terminal post connecting portion 301 and the terminal post 201, making the connection point between the housing connecting portion 302 and the housing 202 a weak point prone to failure.

[0018] If A is too small, the terminal post connecting portion 301 would be thin and the housing connecting portion 302 would be thick, resulting in weak connection strength between the terminal post connecting portion 301 and the terminal post 201, but strong connection strength between the housing connecting portion 302 and the housing 202, making the connection between the terminal post connecting portion 301 and the terminal post 201 a weak point prone to failure. Furthermore, the thin terminal post connecting portion 301 would result in low current-carrying capacity on the terminal post side, and since the wall thickness of the housing 202 in the axial direction of the cylindrical battery is thinner than the thickness of the terminal post 201, the thick housing connecting portion 302 would easily cause deformation of the housing 202 when connected to the housing 202.

[0019] The above cylindrical battery assembly can ensure the balance between the connection strength of the terminal post 201 to the bus bar 300 and the connection strength of the case 202 to the bus bar 300 by controlling the ratio A of the thickness of the terminal post connecting portion 301 to the thickness of the case connecting portion 302 within the range of 0.5-0.9, while ensuring the appropriate current carrying capacity on the terminal post side and avoiding deformation of the case 202 during the connection process between the case 202 and the case connecting portion 302.

[0020] In some embodiments, the terminal post 201 and the busbar 300 are made of different materials, while the housing 202 and the busbar 300 are made of the same material. The melting point of the material of the terminal post 201 is higher than the melting point of the material of the busbar 300. The terminal post 201 is welded to the terminal post connecting portion 301, and the housing 202 is welded to the housing connecting portion 302. For example, the material of the terminal post 201 includes copper, specifically either pure copper material or copper alloy material. Copper has good conductivity, thereby ensuring adequate current-carrying capacity on the terminal post side. The material of the busbar 300 and the housing 202 includes aluminum, specifically either pure aluminum material or aluminum alloy material.

[0021] When the terminal post 201 and the busbar 300 are made of different materials and the melting point of the material of the terminal post 201 is higher than that of the material of the busbar 300, the terminal post 201 is difficult to melt during welding of the terminal post 201 and the terminal post connecting portion 301 of the busbar 300, which impairs the welding quality between the terminal post 201 and the terminal post connecting portion 301. This results in a weak connection strength between the terminal post 201 and the terminal post connecting portion 301, causing an unbalanced connection strength between the terminal post 201 and the housing 202 with the busbar 300.In this case, the thickness of the terminal post connecting portion 301 can be further reduced to improve the welding quality between the terminal post 201 and the terminal post connecting portion 301, thereby ensuring a balanced connection strength between the terminal post 201 and the housing 202 with the busbar 300. Therefore, in this case, the ratio A of the thickness of the terminal post connecting portion 301 to the thickness of the housing connecting portion 302 can be further reduced, so that the range of the ratio A can be further limited to: 0.5≤A≤0.8.

[0022] In some embodiments, a ratio B is defined as the ratio of the thickness of the terminal post connecting portion 301 to the thickness of the terminal post 201 in the axial direction of the cylindrical battery. That is, B is equal to the thickness of the terminal post connecting portion 301 divided by the thickness of the terminal post 201 in the axial direction of the cylindrical battery. The range of B is: 0.25≤B≤0.6. For example, B can be 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, or 0.6. If B is too large, it would impede heat transfer to the terminal post 201 during welding, resulting in poor weld quality. If B is too small, it would result in insufficient weld penetration, which would also result in poor weld quality.Controlling B within the range of 0.25-0.6 can ensure good welding quality between the terminal post 201 and the terminal post connecting portion 301, thereby ensuring a connection strength of the terminal post 201 and the terminal post connecting portion 301.

[0023] In some embodiments, a ratio C is defined as the ratio of the thickness of the housing connecting portion 302 to the wall thickness of the housing 202, i.e., C is equal to the thickness of the housing connecting portion 302 divided by the wall thickness of the housing 202. The C range is: 0.4≤C≤1.5, for example, C can be 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, or 1.5. If C is too large, it would impede heat transfer to the housing 202 during welding, resulting in poor weld quality. If C is too small, it would result in insufficient weld penetration, which also results in poor weld quality. Controlling C in the range of 0.4 to 1.5 can ensure good welding quality between the housing 202 and the housing connecting portion 302, thereby ensuring the joining strength of the housing 202 and the housing connecting portion 302.

[0024] In some embodiments, as in Fig. 5, the housing connecting portion 302 has an arcuate recess c, and as shown in Fig. 3, the arcuate recess c surrounds the outer periphery of the terminal post 201. In this way, the housing terminal portion 302 can provide clearance for the terminal post 201 while maintaining a large contact area with the end surface 202a of the housing, ensuring a sufficient welding area between the end surface 202a of the housing and the housing terminal portion 302, thereby ensuring welding strength.

[0025] In some embodiments, the terminal post 301 has a cylindrical structure. As shown in Fig. As shown in Figure 5, the terminal post connecting portion 301 has a circular region corresponding to the circular end surface of the terminal post 201. The diameter of this circular region is smaller than the diameter of the circular end surface of the terminal post 201 to prevent damage to the edge of the circular end surface of the terminal post 201 during welding.

[0026] In some embodiments, as in Fig. 5, the bus bar 300 includes a transition portion 303. In the arrangement direction of the cylindrical batteries in the cylindrical battery assembly (ie, in the second direction in the figure), the transition portion 303 is disposed between the terminal post connecting portion 301 and the case connecting portion 302 and connects them together. In this way, the relative positions of the terminal post connecting portion 301 and the case connecting portion 302 remain relatively stable during battery vibrations, thereby reducing the likelihood of connection failure between the bus bar 300 and the cylindrical battery 200.

[0027] In some embodiments, as in Fig. 5, the transition portion 303 includes a first transition portion 3031 and a second transition portion 3032. The first transition portion 3031 is connected to the terminal post connecting portion 301, and the second transition portion 3032 is disposed between the first transition portion 3031 and the case connecting portion 302. In the thickness direction of the bus bar 300, which is also the axial direction of the cylindrical battery 200, the second transition portion 3032 is farther from the cylindrical battery 200 than the case connecting portion 302, thereby forming a first bending portion a between the second transition portion 3032 and the case connecting portion 302. The first transition portion 3031 is farther away from the cylindrical battery 200 than the second transition portion 3032, thereby forming a second bending portion b between the second transition portion 3032 and the first transition portion 3031.This configuration makes the bus bar 300 a three-dimensional structure with two bends, which can provide shock absorption and better prevent connection failure between the cylindrical battery 200 and the bus bar 300.

[0028] In some embodiments, as in Fig. 6, in the direction perpendicular to both the axial direction of the cylindrical battery 200 and the arrangement direction of cylindrical batteries in the cylindrical battery assembly (ie, in the third direction in the figure), the width of the case connecting portion 302 is larger than the width of the terminal post connecting portion 301. This can increase the welding area between the case connecting portion 302 and the case 202, thereby improving the connection strength between the case connecting portion 302 and the case 202, and better balancing the connection strength between the case 202 and the case connecting portion 302 and between the terminal post 201 and the terminal post connecting portion 301.

[0029] In some embodiments, as in Fig. 6, in the direction perpendicular to both the axial direction of the cylindrical battery and the arrangement direction of cylindrical batteries in the cylindrical battery assembly (i.e., the third direction in the figure), the width of the second transition portion 3032 is larger than the width of the terminal post connecting portion 301, and the width of the first transition portion 3031 gradually decreases from the second transition portion 3032 to the terminal post connecting portion 301. In this way, the second transition portion 3032 uses less material, which contributes to reducing the cost of the bus bar 300.

[0030] Note that when the axial direction of the cylindrical battery 200 is perpendicular to the base plate 101, the above-mentioned third direction is parallel to the base plate 101. When the axial direction of the cylindrical battery 200 is parallel to the base plate 101, the above-mentioned third direction is perpendicular to the base plate 101.

[0031] In some embodiments, the busbar 300 is an integrally formed structure.

[0032] In some embodiments, as in Fig. 5, the thickness of the transition portion 303 of the bus bar 300 is equal to the thickness of the housing connecting portion 302, both of which are greater than the thickness of the terminal post connecting portion 301 of the bus bar 300.

[0033] In some embodiments, as in Fig. 2, the cylindrical battery assembly includes an insulation plate 400 disposed at the end of the cylindrical battery 200 where the terminal post 201 is located. As shown in Fig. 5, a fixing hole d is provided on the transition portion 303, and the transition portion 303 is fixed to the insulation plate 400 through the fixing hole d.

[0034] In particular, in the illustrated embodiment, as shown in Fig. 2, the transition portions 303 of all busbars 300 of the two stacked groups of cylindrical battery assemblies are fixed to the same insulation plate 400 through their respective fixing holes d. As shown in Fig.As shown in Figure 7, the insulation plate 400 is provided with two rows of free areas 401 and four rows of terminal posts 402. The upper row of free areas 401 is used to receive the case connecting portions 302 of the busbars 300 and the terminal posts 201 of the cylindrical batteries 200 of the upper battery assembly layer, while the lower row of free areas 401 is used to receive the case connecting portions 302 of the busbars 300 and the terminal posts 201 of the cylindrical batteries 200 of the lower battery assembly layer. The upper two rows of terminal posts 402 are used to insert through the mounting holes d of the busbars 300 of the upper battery assembly layer, while the lower two rows of terminal posts 402 are used to insert through the mounting holes d of the busbars 300 of the lower battery assembly layer.

[0035] The above specific examples were used to illustrate the principles and implementation methods of the present application. The explanation of the above embodiments is used only to aid in understanding the method and core concepts of the present application. It should be understood that various improvements and modifications to the present application can be made by those skilled in the art without departing from the principles of the present application, and these improvements and modifications also fall within the scope of the claims of the present application.

Claims

[1] Cylindrical battery arrangement, characterized by that the cylindrical battery assembly comprises a cylindrical battery (200) and a busbar (300), the cylindrical battery (200) comprises a housing (202) and a terminal post (201), the terminal post (201) is arranged on an end surface (202a) of the housing (202), a wall thickness of the housing (202) in an axial direction of the cylindrical battery is less than a thickness of the terminal post (201), the busbar (300) comprises a terminal post connecting portion (301) which is electrically connected to the side of the terminal post (201) facing away from the housing (202), and a housing connecting portion (302) which is electrically connected to the housing (202), wherein a ratio A of a thickness of the terminal post connecting portion (301) to a thickness of the housing connecting portion (302) is in the range of 0.5≤A≤0.

9. [2] Cylindrical battery arrangement according to claim 1, characterized by that the terminal post (201) and the busbar (300) are made of different materials, the housing (202) and the busbar (300) are made of the same material, the terminal post (201) is welded to the terminal post connecting portion (301), the housing (202) is welded to the housing connecting portion (302), a melting point of the material of the terminal post (201) is higher than a melting point of the material of the busbar (300), the ratio A is in the range of 0.5≤A≤0.

8. [3] Cylindrical battery arrangement according to claim 1 or 2, characterized by that the material of the terminal post (201) comprises copper and the material of the busbar (300) and the housing (202) comprises aluminum. [4] Cylindrical battery arrangement according to one of the preceding claims, characterized bythat a ratio B of the thickness of the terminal post connecting portion (301) to the thickness of the terminal post (201) in the axial direction of the cylindrical battery is in the range of 0.25≤B≤0.6; and / or a ratio C of the thickness of the housing connecting portion (302) to the wall thickness of the housing (202) is in the range of 0.4≤C≤1.

5. [5] Cylindrical battery arrangement according to one of the preceding claims, characterized by that the housing connecting portion (302) has an arcuate recess (c) and the arcuate recess (c) surrounds an outer periphery of the terminal post (201). [6] Cylindrical battery arrangement according to one of the preceding claims, characterized by that the terminal post (201) is a cylindrical structure and the terminal post connecting portion (301) has a circular area corresponding to a circular end surface of the terminal post (201). [7] Cylindrical battery arrangement according to one of the preceding claims, characterized by in that in a direction both perpendicular to the axial direction of the cylindrical battery and perpendicular to an arrangement direction of cylindrical batteries in the cylindrical battery assembly, a width of the case connecting portion (302) is greater than a width of the terminal post connecting portion (301). [8] Cylindrical battery arrangement according to one of the preceding claims, characterized by in that the busbar (300) has a transition section (303), wherein the transition section (303) is arranged between the terminal post connecting section (301) and the housing connecting section (302) in the arrangement direction of cylindrical batteries in the cylindrical battery assembly, the transition section (303) connecting the terminal post connecting section (301) and the housing connecting section (302) to each other. [9] Cylindrical battery arrangement according to claim 8, characterized by in that the transition section (303) has a first transition section (3031) connected to the terminal post connecting section (301), and a second transition section (3032) arranged between the first transition section (3031) and the housing connecting section (302), a first bending section (a) is formed between the second transition section (3032) and the housing connecting section (302), and a second bending section (b) is formed between the second transition section (3032) and the first transition section (3031). [10] Cylindrical battery arrangement according to claim 9, characterized byin the direction both perpendicular to the axial direction of the cylindrical battery and perpendicular to the arrangement direction of cylindrical batteries in the cylindrical battery assembly, a width of the second transition portion (3032) is greater than a width of the terminal post connecting portion (301), a width of the first transition portion (3031) gradually decreases from the second transition portion (3032) to the terminal post connecting portion (301). [11] Cylindrical battery arrangement according to claim 8, characterized by that a fastening hole (d) is provided on the transition section (303), the cylindrical battery assembly has an insulation plate (400), the insulation plate (400) is arranged at one end of the cylindrical battery (200) at which the terminal post (201) is arranged, the transition section (303) is fastened to the insulation plate (400) through the fastening hole (d). [12] Cylindrical battery arrangement according to one of the preceding claims, characterized by that the material of the housing (202) comprises aluminum, the cylindrical battery comprises a cell, the cell has a positive tab and a negative tab, the positive tab is electrically connected to the housing (202) and the negative tab is electrically connected to the terminal post (201). [13] Battery device, characterized by that the battery device comprises a housing (100) and at least one cylindrical battery arrangement according to one of the preceding claims, which is arranged in the housing (100). [14] Battery device according to claim 13, characterized by that the housing (100) has a base plate (101), wherein an axial direction of the cylindrical battery (200) of the cylindrical battery assembly is parallel to or perpendicular to the base plate (101).

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