Bus plate structure and battery pack

Abstract

This application proposes a bus plate structure. The positive electrode bus plate includes a bus plate body and a bus plate lead tab connected to each other. The bus plate body is provided with a central drainage hole penetrating in its own thickness direction, and one surface in the thickness direction of the bus plate body is a welding surface for welding to the positive tab of the wound electrode group as a whole. This application also proposes a battery pack including the above bus plate structure.

Description

Technical Field

[0001] This application claims the priority of Chinese Patent Application No. 2023202032336 filed with the China National Intellectual Property Administration on February 10, 2023, and Chinese Patent Application No. 2023101088184 filed with the China National Intellectual Property Administration on February 10, 2023. All the contents of the above applications are incorporated herein by reference. This application relates to the technical field of bus plates, and particularly to bus plate structures and battery packs.

Background Art

[0002] Compared with conventional batteries such as nickel-cadmium batteries and lead-acid batteries, lithium-ion batteries have advantages such as high energy density, high operating voltage, low self-discharge rate, long cycle life, high charge-discharge efficiency, wide operating temperature range, and less environmental pollution. Currently, lithium-ion batteries are widely used in 3C devices such as mobile phones and laptops, as well as new energy vehicles, and are also expected to have a wide range of applications in the aerospace field such as civil aircraft, drones, and space exploration vehicles.

[0003] Currently, lithium-ion batteries usually use laser welding to weld the exposed positive electrode tabs of the positive electrode bus plate and the wound electrode group. However, the forming process of the positive electrode bus plate in the prior art is relatively complex, with arc, flange, and other structures, as well as a plurality of protrusions and one or more slot structures. As a result, the welding area becomes small, and the problem of soldering defects is likely to occur, leaving room for improvement.

Summary of the Invention

Problems to be Solved by the Invention

[0004] One object of this application is to propose a bus plate structure with a large welding area and reduced occurrence of soldering defects.

Means for Solving the Problems

[0005] In a first aspect, the present application provides a positive electrode bus plate including a bus plate main body and a bus plate lead-out tab connected to each other, wherein a central drain hole is provided through the bus plate main body in its thickness direction, and one surface of the bus plate main body in the thickness direction is a welding surface for welding to the positive electrode tab of the wound electrode group as a whole, providing a bus plate structure.

[0006] In one embodiment, one or more edge drain holes are provided at intervals on the outer side in the circumferential direction of the bus plate main body.

[0007] In one embodiment, inner drain holes are provided through the bus plate main body in its thickness direction, and the inner drain holes are provided adjacent to the central drain hole.

[0008] In one embodiment, the welding surface of the bus plate main body is welded by laser screw harness welding or laser spot welding.

[0009] In one embodiment, in one or more of the laser screw harness weldings, a screw harness welding outer boundary and a screw harness welding inner boundary are formed, the screw harness welding outer boundary and the screw harness welding inner boundary are circular, provided concentrically with the central drain hole, and the center of the inner drain hole is on the screw harness welding outer boundary, or, in one or more of the laser spot weldings, a spot welding outer boundary and a spot welding inner boundary are formed, the spot welding outer boundary and the spot welding inner boundary are circular, provided concentrically with the central drain hole, and the center of the inner drain hole is on the spot welding outer boundary.

[0010] In one embodiment, on two surfaces of the bus plate main body in the thickness direction, bosses and grooves are provided in a one-to-one correspondence, the grooves and the bosses are of the same shape and aligned, the bosses are provided on the welding surface, and at least a part of the bosses extends to the edge of the bus plate main body.

[0011] In one embodiment, one or more bosses are provided, which are arc-shaped, and both ends of each boss extend to the edge of the bus plate body, defining a positive electrode current collection region at the edge portion of the bus plate body, and one or more of the edge drainage holes are provided in a one-to-one correspondence with one or more of the positive electrode current collection regions.

[0012] In one embodiment, one or more electrolyte positive electrode infiltration channels penetrate through the bus plate body in its thickness direction.

[0013] In one embodiment, one or more of the electrolyte positive electrode infiltration channels are distributed in an annular array centered on the central drainage hole. The region between the central drainage hole and one or more of the electrolyte positive electrode infiltration channels is welded by laser screw harness welding or laser spot welding.

[0014] In one embodiment, in one or more laser screw harness weldings, a screw harness welding outer boundary and a screw harness welding inner boundary are formed. The screw harness welding outer boundary and the screw harness welding inner boundary are circular, provided concentrically with the central drainage hole, and one or more of the electrolyte positive electrode infiltration channels are provided outside the screw harness welding outer boundary. Alternatively, in one or more of the laser spot weldings, a spot welding outer boundary and a spot welding inner boundary are formed. The spot welding outer boundary and the spot welding inner boundary are circular, provided concentrically with the central drainage hole, and one or more of the electrolyte positive electrode infiltration channels are provided outside the spot welding outer boundary.

[0015] In one embodiment, on two surfaces in the thickness direction of the bus plate body, bosses and grooves are provided in a one-to-one correspondence. The grooves and the bosses are aligned in the same shape, and the bosses are provided on the welding surface. One or more bosses are provided, which are arc-shaped. Both ends of each boss extend to the edge of the bus plate body, and an electrolytic solution positive electrode infiltration channel is provided between two adjacent bosses.

[0016] In one embodiment, an intermediate welding spot group is provided at the center position of one surface in the thickness direction. The welding spots of the intermediate welding spot group are distributed in at least two rows in the first direction. The welding spots in each row are distributed at intervals, and a negative electrode bus plate is further included, in which two adjacent rows of the welding spots are provided with shifted positions.

[0017] In one embodiment, one or more electrolytic solution negative electrode infiltration channels penetrate through the negative electrode bus plate in its own thickness direction.

[0018] In one embodiment, one or more of the electrolytic solution negative electrode infiltration channels are distributed in an annular array centered on the intermediate welding spot group.

[0019] The area between two adjacent electrolytic solution negative electrode infiltration channels is welded by laser screw harness welding or laser spot welding.

[0020] In a second aspect, the present application also provides a battery pack including the above bus plate structure.

Advantages of the Invention

[0021] As described above, the present application has the following technical effects. According to this embodiment, in the conventional bus plate, there are a plurality of protrusions and one or more slot structures, and welding cannot be performed on the protrusions and slots. As a result, its own welding area is small. On the other hand, the structure of the bus plate of the present invention is simplified. Except for the necessary central drainage hole, one surface of the bus plate body itself can be used for welding the positive tabs of the wound electrode group as a whole. The increase in the welding surface effectively increases the contact area with the positive tabs of the wound electrode group, increases the area through which current flows, effectively improves the rate characteristics of the tabs, improves the current passing ability of the battery, and reduces heat generation. Furthermore, the use of the full-surface welding technology on the bus plate body is beneficial to the welding stability of the bus plate structure and the reduction of soldering defects.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Mode for Carrying Out the Invention

[0023] In the description of the present application, the directions and positional relationships indicated by "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. are based on the directions and positional relationships shown in the drawings, and are for the convenience of description of the present application to simplify the description. Such directions or positional relationships do not indicate or imply that the device or device must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present application.

[0024] Hereinafter, the bus plate structure and the battery pack according to the embodiments of the present application will be described with reference to FIGS. 1 to 12. Hereinafter, some embodiments of the present application will be described in detail with reference to the drawings. As long as there is no contradiction, the following embodiments and the features of the embodiments may be combined with each other.

[0025] Compared with conventional batteries such as nickel-cadmium batteries and lead-acid batteries, lithium-ion batteries have advantages such as high energy density, high operating voltage, low self-discharge rate, long cycle life, high charge and discharge efficiency, wide operating temperature range, and less environmental pollution. At present, lithium-ion batteries are widely used in 3C devices such as mobile phones and notebook computers, as well as new energy vehicles, and are expected to have a wide range of applications in the aerospace field such as civil aircraft, drones, and space exploration vehicles.

[0026] At present, lithium-ion batteries usually use laser welding to weld the positive electrode bus plate 1 to the exposed positive electrode tab of the wound electrode group. However, the forming process of the positive electrode bus plate 1 in the prior art is relatively complicated, and has an arc, a flange, other structures, as well as a plurality of protrusions and one or more slot structures. As a result, the welding area becomes small, and the problem of poor soldering is likely to occur, and there is room for improvement.

[0027] In view of the above, an embodiment of the present application proposes a bus plate structure that improves the structure of the positive electrode bus plate 1 to increase the contact area during welding between the positive electrode bus plate 1 and the positive tab of the wound electrode group, which is advantageous for improving the welding stability of the positive electrode bus plate 1 and reducing soldering defects.

[0028] Hereinafter, various specific embodiments will be shown.

[0029] Example 1 As shown in FIGS. 1 to 4, the bus plate structure proposed in Example 1 of the present application includes a positive electrode bus plate 1 including a bus plate main body 11 and a bus plate lead-out tab 12 connected to each other. The bus plate main body 11 is provided with a central drainage hole 13 penetrating in its own thickness direction, and one surface in the thickness direction of the bus plate main body 11 is a welding surface for welding to the positive tab of the wound electrode group as a whole.

[0030] According to Example 1, in the conventional bus plate, there are a plurality of protrusions and one or more slot structures, and welding cannot be performed on the protrusions and slots. As a result, the welding area of itself becomes small. On the other hand, the bus plate structure of the present invention is simplified. Except for the necessary central drainage hole 13, one surface of the bus plate main body 11 itself can be used as a whole for welding the positive tab of the wound electrode group. The increase in the welding surface effectively increases the contact area with the positive tab of the wound electrode group, increases the area through which current flows, effectively improves the rate characteristics of the tab, improves the current passing ability of the battery, and reduces heat generation. Furthermore, the use of the full-surface welding technology for the bus plate main body 11 is advantageous for improving the welding stability of the bus plate structure and reducing soldering defects. Furthermore, the bus plate structure of the present invention not only has a simple structure, but also can improve the manufacturing efficiency and reduce the cost.

[0031] Specifically, the central drainage hole 13 faces the central hole of the wound electrode group, whereby drainage can be ensured as much as possible. Optionally, the diameter of the central drainage hole 13 matches the size of the central hole of the wound electrode group.

[0032] Specifically, the bus plate extraction tab 12 and the cap of the cover plate assembly are connected by laser welding, and the surface of the bus plate body 11 and the positive tab of the wound electrode group is welded by laser harness welding. Optionally, the material of the positive bus plate 1 is, for example, an aluminum material in the AL 1060-O state.

[0033] Furthermore, as shown in FIGS. 1 to 4, one or more edge drainage holes 14 are provided at intervals on the outer side in the circumferential direction of the bus plate body 11. According to the first embodiment, the edge drainage holes 14 are formed on the side of the bus plate body 11. When the liquid injection operation is performed, after the electrolytic solution reaches the bus plate body 11, it is drained into the wound electrode group through the central drainage hole 13. On the other hand, in this embodiment, in addition to the central drainage hole 13, the edge drainage holes 14 are provided. Therefore, the electrolytic solution is drained into the wound electrode group through both the central drainage hole 13 and the edge drainage holes 14, which is advantageous for improving the drainage capacity. Optionally, the shape of the edge drainage holes 14 is semi-circular. Of course, in other embodiments, the edge drainage holes 14 may have a square or half-oval shape.

[0034] Specifically, as shown in FIG. 1, two edge drainage holes 14 are provided, and the two edge drainage holes 14 are respectively provided on the upper and lower sides of the bus plate body 11.

[0035] Furthermore, as shown in FIGS. 1 to 4, the bus plate body 11 is provided with an inner drain hole 15 penetrating in its own thickness direction, and the inner drain hole 15 is provided adjacent to the central drain hole 13. According to Embodiment 1, the inner drain hole 15 is provided in the bus plate body 11. When the liquid injection operation is performed, after the electrolytic solution reaches the bus plate body 11, it is drained into the wound electrode group through the central drain hole 13. On the other hand, in this embodiment, in addition to the central drain hole 13, the inner drain hole 15 is provided. Therefore, the electrolytic solution is drained into the wound electrode group through both the central drain hole 13 and the inner drain hole 15, which is advantageous for improving the drainage capacity. Optionally, the shape of the inner drain hole 15 is circular. Of course, in other embodiments, the inner drain hole 15 may be square or oval.

[0036] In addition, according to Embodiment 1, the statement that the entire surface of one side in the thickness direction of the bus plate body 11 is the welding surface means that all other surfaces of the bus plate body 11 except the central drain hole 13, the edge drain hole 14, and the inner drain hole 15 are used for welding with the positive tab of the wound electrode group.

[0037] Furthermore, as shown in FIG. 4, the welding surface of the bus plate body 11 is welded by laser screw harness welding 2. According to Embodiment 1, in laser screw welding, a plurality of circular welding spots are formed between the welding spots by spot welding, so that the joint area in welding is effectively increased. Due to the increase in the joint area, the deformation of the bus plate body 11 is suppressed, and the rigidity of the bus plate body 11 is improved. Also, the welding energy is uniform, the shapes, welding depths, and strengths of the welding spots are highly consistent, it has a smooth and beautiful appearance, no deformation, and reliable and strong welding is possible.

[0038] Specifically, in one or more laser screw harness welds 2, a screw harness weld outer boundary 21 and a screw harness weld inner boundary 22 are formed. The center of the inner drain hole 15 is on the screw harness weld outer boundary 21. Both the screw harness weld outer boundary 21 and the screw harness weld inner boundary 22 are circular, are provided concentrically with the central drain hole 13, and the screw harness weld outer boundary 21, the screw harness weld inner boundary 22, and the central drain hole 13 are provided in order from the inside to the outside. Optionally, the inner drain hole 15 is provided between two adjacent laser screw harness welds 2.

[0039] Of course, in some other embodiments, according to FIG. 3, the welding surface of the bus plate body 11 may be welded by laser spot welding 3. Laser spot welding 3 has advantages such as high speed, high precision, low heat input, small deformation of the workpiece, precise control possible, small focusing spot, high positioning accuracy, and easy automation.

[0040] Specifically, in one or more laser spot welds 3, a spot weld outer boundary 31 and a spot weld inner boundary 32 are formed. The center of the inner drain hole 15 is on the spot weld outer boundary 31. Both the spot weld outer boundary 31 and the spot weld inner boundary 32 are circular, are provided concentrically with the central drain hole 13, and the spot weld outer boundary 31, the spot weld inner boundary 32, and the central drain hole 13 are provided in order from the inside to the outside. Optionally, the inner drain hole 15 is provided between two adjacent laser spot welds 3.

[0041] In addition to the bus plate structure, the embodiments of the present application propose a battery pack including the above bus plate structure.

[0042] Embodiment 2 As shown in FIGS. 5 to 8, the bus plate structure proposed in Example 2 of the present application includes a positive electrode bus plate 1 including a bus plate main body 11 and a bus plate lead tab 12 connected to each other. The bus plate main body 11 is provided with a central drain hole 13 penetrating in its own thickness direction, and one surface in the thickness direction of the bus plate main body 11 is a welding surface for welding to the positive tab of the wound electrode group as a whole.

[0043] According to Example 2, in the conventional bus plate, there are a plurality of protrusions and one or more slot structures, and welding cannot be performed on the protrusions and slots. As a result, its own welding area becomes small. On the other hand, the bus plate structure of the present invention is simplified. Except for the necessary central drain hole 13, one surface of the bus plate main body 11 itself can be used as a whole for welding the positive tab of the wound electrode group. The increase in the welding surface effectively increases the contact area with the positive tab of the wound electrode group, increases the area through which current flows, effectively improves the rate characteristics of the tab, improves the current passing ability of the battery, and reduces heat generation. Furthermore, the use of the full-surface welding technology for the bus plate main body 11 is advantageous for improving the welding stability of the bus plate structure and reducing soldering defects. Furthermore, the bus plate structure of the present invention not only has a simple structure, but also can improve the manufacturing efficiency and reduce the cost.

[0044] Specifically, the central drain hole 13 faces the central hole of the wound electrode group, whereby drainage can be ensured as much as possible. Optionally, the diameter of the central drain hole 13 matches the size of the central hole of the wound electrode group.

[0045] Specifically, the bus plate lead tab 12 and the cap of the cover plate assembly are connected by laser welding, and the surfaces of the bus plate main body 11 and the positive tab of the wound electrode group are welded by laser harness welding. Optionally, the material of the positive electrode bus plate 1 uses, for example, an aluminum material in the AL 1060-O state.

[0046] Furthermore, as shown in FIGS. 5 to 8, one or more edge drainage holes 14 are provided at intervals on the outer side in the circumferential direction of the bus plate body 11. According to the second embodiment, the edge drainage holes 14 are formed on the side edges of the bus plate body 11. When the liquid injection operation is performed, after the electrolytic solution reaches the bus plate body 11, it is drained into the wound electrode group through the central drainage hole 13. On the other hand, in this embodiment, in addition to the central drainage hole 13, the edge drainage holes 14 are provided. Therefore, the electrolytic solution is drained into the wound electrode group through both the central drainage hole 13 and the edge drainage holes 14, which is advantageous for improving the drainage capacity. Optionally, the shape of the edge drainage holes 14 is semi-circular. Of course, in other embodiments, the edge drainage holes 14 may have a square or semi-elliptical shape.

[0047] Furthermore, as shown in FIGS. 5 to 8, on the two surfaces in the thickness direction of the bus plate body 11, the bosses 16 and the grooves 17 are provided in a one-to-one correspondence. The grooves 17 and the bosses 16 are of the same shape and are aligned. The bosses 16 are provided on the welding surface. At least a part of the bosses 16 themselves extends to the edge of the bus plate body 11. According to the second embodiment, by providing the bosses 16 as the welding surface, the bosses 16 themselves have a sufficient contact area with the positive tab of the wound electrode group, ensuring a sufficient welding area between the bus plate body 11 and the positive tab of the wound electrode group, and effectively avoiding the problem of poor soldering. In addition, compared with full-surface welding, the welding efficiency is improved, and further the manufacturing efficiency is improved. Furthermore, the grooves 17 formed on the surface of the bus plate body 11 play a role in positioning between the bus plate body 11 and the wound electrode group, making it easier for the operator to confirm the position of the bosses 16, which is advantageous for welding.

[0048] Furthermore, as shown in FIGS. 5 to 8, one or more bosses 16 are provided, which are arc-shaped. Both ends of each boss 16 extend to the edge of the bus plate body 11, defining a positive electrode current collecting region 111 at the edge portion of the bus plate body 11. One or more edge drainage holes 14 are provided in a one-to-one correspondence with one or more positive electrode current collecting regions 111. According to Example 2 of the present invention, the edge drainage holes 14 assist in improving the drainage ability, and the groove 17 plays a role in positioning between the bus plate body 11 and the wound electrode group. Therefore, in order to avoid the problem of poor soldering in the welding of the boss 16 corresponding to the groove 17, the edge drainage holes 14 are provided not in the groove 17 but in the positive electrode current collecting region 111. In this way, it assists in improving the drainage ability and ensures a sufficient contact area.

[0049] Specifically, as shown in FIGS. 5 to 8, three bosses 16 are provided. The three bosses 16 are provided on the upper side, left side, and lower side of the bus plate body 11. The three bosses 16 are distributed in an annular array centered on the central drainage hole 13. In this case, three grooves 17 are also provided. The three grooves 17 are also provided on the upper side, left side, and lower side of the bus plate body 11. The three bosses 16 are also distributed in an annular array centered on the central drainage hole 13, and three defined positive electrode current collecting regions 111 are also provided. Furthermore, three edge drainage holes 14 are also provided, and the three edge drainage holes 14 are provided in a one-to-one correspondence with the three positive electrode current collecting regions 111.

[0050] In addition to the bus plate structure, the embodiment of the present application proposes a battery pack including the above bus plate structure.

[0051] Example 3 As shown in FIG. 9, the bus plate structure proposed in Example 3 of the present application includes a positive electrode bus plate 1 including a bus plate body 11 and a bus plate lead tab 12 connected to each other. The bus plate body 11 is provided with a central drainage hole 13 penetrating in its own thickness direction. One surface in the thickness direction of the bus plate body 11 is a welding surface for welding to the positive electrode tab of the wound electrode group as a whole.

[0052] According to Embodiment 3 of the present invention, in a conventional bus plate, there are a plurality of protrusions and one or more slot structures, and welding cannot be performed on the protrusions and slots. As a result, the welding area of the bus plate itself becomes small. On the other hand, the bus plate structure of the present invention is simplified. Except for the necessary central drain hole 13, one surface of the bus plate body 11 itself can be used as a whole for welding the positive tabs of the wound electrode group. Due to the increase in the welding surface, the contact area with the positive tabs of the wound electrode group is effectively increased, the area through which current flows becomes larger, the rate characteristics of the tabs are effectively improved, the current passing ability of the battery is improved, and heat generation is reduced. Furthermore, the use of full-surface welding technology for the bus plate body 11 is advantageous for improving the welding stability of the bus plate structure and reducing soldering defects. Furthermore, the bus plate structure of the present invention not only has a simple structure, but also can improve manufacturing efficiency and reduce costs.

[0053] Specifically, the central drain hole 13 faces the central hole of the wound electrode group, whereby drainage can be ensured as much as possible. Optionally, the diameter of the central drain hole 13 matches the size of the central hole of the wound electrode group.

[0054] Specifically, the bus plate lead tab 12 and the cap of the cover plate assembly are connected by laser welding, and the surface of the bus plate body 11 and the positive tabs of the wound electrode group are welded by laser harness welding. Optionally, the material of the positive bus plate 1 is, for example, an aluminum material in the AL 1060-O state.

[0055] Furthermore, according to FIG. 9, one or more electrolyte positive infiltration channels 18 are provided through the bus plate body 11 in its thickness direction. According to Embodiment 3 of the present invention, the provided electrolyte positive infiltration channels 18 increase the transport channels of the electrolyte inside the electrode group and the exhaust channels for coping with thermal runaway, improve the injection efficiency, and increase the exhaust speed during thermal runaway of the electrode group.

[0056] Note that according to the third embodiment, the statement that the entire one surface in the thickness direction of the bus plate body 11 is a welding surface means that all the other surfaces of the bus plate body 11 except the electrolytic solution positive electrode infiltration channel 18 of the bus plate body 11 are used for welding with the positive electrode tab of the wound electrode group.

[0057] Furthermore, as shown in FIG. 9, one or more electrolytic solution positive electrode infiltration channels 18 are distributed in an annular array centered on the central drain hole 13, and the region between the central drain hole 13 and one or more electrolytic solution positive electrode infiltration channels 18 is welded by laser screw harness welding 2. According to the third embodiment, in laser screw welding, a plurality of circular welding spots are formed between the welding spots by spot welding, so that the joint area in welding is effectively increased. With the increase of the joint area, the deformation of the bus plate body 11 is suppressed and the rigidity of the bus plate body 11 is improved. In addition, the welding energy is uniform, the shapes, welding depths, and consistencies of the welding spots are good, the appearance is smooth and beautiful, there is no deformation, and strong and reliable welding is possible.

[0058] Specifically, as shown in FIG. 9, in one or more laser screw harness weldings 2, a screw harness welding outer boundary 21 and a screw harness welding inner boundary 22 are formed. The screw harness welding outer boundary 21 and the screw harness welding inner boundary 22 are circular and are provided concentrically with the central drain hole 13. The screw harness welding outer boundary 21, the screw harness welding inner boundary 22, and the central drain hole 13 are provided in order from the inside to the outside. One or more electrolytic solution positive electrode infiltration channels 18 are provided outside the screw harness welding outer boundary 21.

[0059] Of course, in other embodiments, the region between the central drainage hole 13 and the one or more electrolyte positive electrode infiltration channels 18 may be welded by laser spot welding 3. In the one or more laser spot weldings 3, a spot weld outer boundary 31 and a spot weld inner boundary 32 are formed. The spot weld outer boundary 31 and the spot weld inner boundary 32 are circular and are provided concentrically with the central drainage hole 13. The one or more electrolyte positive electrode infiltration channels 18 are provided outside the spot weld outer boundary 31.

[0060] In addition to the bus plate structure, the embodiments of the present application propose a battery pack including the above bus plate structure.

[0061] Embodiment 4 According to FIG. 10, the bus plate structure proposed in Embodiment 4 of the present application includes a positive electrode bus plate 1 including a bus plate main body 11 and a bus plate lead tab 12 connected to each other. The bus plate main body 11 is provided with a central drainage hole 13 penetrating in its own thickness direction, and one surface in the thickness direction of the bus plate main body 11 is a welding surface for welding to the positive electrode tab of the wound electrode group as a whole.

[0062] According to this Embodiment 4, in the conventional bus plate, there are a plurality of protrusions and one or more slot structures, and welding cannot be performed on the protrusions and slots. As a result, its own welding area becomes small. On the other hand, the bus plate structure of the present invention is simplified. Except for the necessary central drainage hole 13, one surface of the bus plate main body 11 itself can be used for welding the positive electrode tab of the wound electrode group as a whole. The increase in the welding surface effectively increases the contact area with the positive electrode tab of the wound electrode group, increases the area through which the current flows, effectively improves the rate characteristics of the tab, improves the current passing ability of the battery, and reduces heat generation. Furthermore, the use of the full-surface welding technology for the bus plate main body 11 is advantageous for improving the welding stability of the bus plate structure and reducing soldering defects. Furthermore, the bus plate structure of the present invention not only has a simple structure, but also can improve the manufacturing efficiency and reduce the cost.

[0063] Specifically, the central drainage hole 13 faces the central hole of the wound electrode group, whereby drainage can be ensured as much as possible. Optionally, the diameter of the central drainage hole 13 matches the size of the central hole of the wound electrode group.

[0064] Specifically, the bus plate extraction tab 12 and the cap of the cover plate assembly are connected by laser welding, and the surface of the bus plate body 11 and the positive tab of the wound electrode group are welded by laser harness welding. Optionally, the material of the positive bus plate 1 is, for example, an aluminum material in the AL 1060-O state.

[0065] Furthermore, as shown in FIG. 10, one or more electrolyte positive electrode infiltration channels 18 penetrate the bus plate body 11 in its thickness direction. According to Example 4 of the present application, the provided electrolyte positive electrode infiltration channels 18 increase the transport channel of the electrolyte inside the electrode group and the exhaust channel corresponding to thermal runaway, improve the liquid injection efficiency, and increase the exhaust speed during thermal runaway of the electrode group.

[0066] Furthermore, as shown in FIG. 10, on two surfaces in the thickness direction of the bus plate body 11, bosses 16 and grooves 17 are provided in a one-to-one correspondence. The grooves 17 and the bosses 16 are of the same shape and are aligned. The bosses 16 are provided on the welding surface. One or more bosses 16 are provided, and they are arc-shaped. Both ends of each boss 16 extend to the edge of the bus plate body 11, and an electrolyte positive electrode infiltration channel 18 is provided between two adjacent bosses 16. According to Example 4 of the present application, the electrolyte positive electrode infiltration channel 18 improves the liquid injection efficiency, and the groove 17 plays a role in positioning between the bus plate body 11 and the wound electrode group. Therefore, in order to avoid the problem of poor soldering in the welding of the boss 16 corresponding to the groove 17, the electrolyte positive electrode infiltration channel 18 is provided between two adjacent bosses 16 instead of the boss 16, thus improving the liquid injection efficiency and ensuring a sufficient contact area.

[0067] In addition to the bus plate structure, the embodiment of the present application proposes a battery pack including the above bus plate structure.

[0068] Example 5 As shown in FIGS. 11 and 12, the bus plate structure proposed in Example 5 of the present application includes a positive bus plate 1 including a bus plate main body 11 and a bus plate extraction tab 12 connected to each other. The bus plate main body 11 is provided with a central drainage hole 13 penetrating in its own thickness direction, and one surface in the thickness direction of the bus plate main body 11 is a welding surface for welding to the positive tab of the wound electrode group as a whole.

[0069] According to this Example 5, in the conventional bus plate, there are a plurality of protrusions and one or more slot structures, and welding cannot be performed on the protrusions and slots. As a result, the welding area of itself becomes small. On the other hand, the bus plate structure of the present invention is simplified. Except for the necessary central drainage hole 13, one surface of the bus plate main body 11 itself can be used as a whole for welding the positive tab of the wound electrode group. The increase in the welding surface effectively increases the contact area with the positive tab of the wound electrode group, increases the area through which the current flows, effectively improves the rate characteristics of the tab, improves the current passing ability of the battery, and reduces heat generation. Structurally, a full-surface welding technique is adopted for the bus plate main body 11, which is advantageous for the welding stability of the bus plate structure and the reduction of soldering defects. Furthermore, the bus plate structure of the present invention can not only simplify the structure, but also improve the manufacturing efficiency and reduce the cost.

[0070] Specifically, the central drainage hole 13 faces the central hole of the wound electrode group, whereby drainage can be ensured as much as possible. Optionally, the diameter of the central drainage hole 13 matches the size of the central hole of the wound electrode group.

[0071] Specifically, the bus plate extraction tab 12 and the cap of the cover plate assembly are connected by laser welding, and the surfaces of the bus plate main body 11 and the positive tab of the wound electrode group are welded by laser harness welding. Optionally, the material of the positive bus plate 1 uses, for example, an aluminum material in the AL 1060-O state.

[0072] Furthermore, as shown in FIG. 11, in the bus plate structure, an intermediate welding spot group 41 is provided at the center position of one surface in the thickness direction, the welding spots of the intermediate welding spot group 41 are distributed in at least two rows in the first direction, the welding spots in each row are distributed at intervals, and the negative electrode bus plate 4 in which two adjacent rows of welding spots are provided with shifted positions is further included. The first direction is the vertical direction in the coordinate system of FIG. 11.

[0073] According to the fifth embodiment, this bus plate structure is simple, and a unique offset embossing welding structure is provided at the center of the negative electrode bus plate 4, whereby the welding area of the negative electrode bus plate 4 is maximally ensured. Furthermore, since spot welding and back welding are performed by resistance welding, the welding strength is high and the stability is good.

[0074] Furthermore, as shown in FIG. 12, one or more electrolyte negative electrode infiltration channels 42 penetrate the negative electrode bus plate 4 in its own thickness direction. Optionally, four electrolyte negative electrode infiltration channels 42 are provided, and the four electrolyte negative electrode infiltration channels 42 are provided on the upper side, left side, lower side, and right side of the negative electrode bus plate 4. According to the fifth embodiment, a sufficient welding area between the negative electrode bus plate 4 and the tab is left, and the provided electrolyte negative electrode infiltration channels 42 increase the transport channel of the electrolyte inside the electrode group and the exhaust channel for coping with thermal runaway, the liquid injection efficiency is increased, and the exhaust speed during thermal runaway of the electrode group is increased.

[0075] Furthermore, as shown in FIG. 12, one or more electrolyte negative electrode infiltration channels 42 are distributed in an annular array centered on the intermediate welding spot group 41, and the region between two adjacent electrolyte negative electrode infiltration channels 42 is welded by laser screw harness welding 2. According to Example 5 of the present invention, in laser screw welding, a plurality of circular welding spots are formed between the welding spots by spot welding, so that the joint area in welding is effectively increased. Due to the increase in the joint area, the deformation of the bus plate body 11 is suppressed, and the rigidity of the bus plate body 11 is improved. In addition, the welding energy is uniform, the shape, welding depth, and strength consistency of the welding spots are good, the appearance is smooth and beautiful, there is no deformation, and strong and reliable welding is possible.

[0076] Of course, in other embodiments, the region between two adjacent electrolyte negative electrode infiltration channels 42 is welded by laser spot welding 3. Laser spot welding 3 has the advantages of high speed, high precision, low heat input, small deformation of the workpiece, accurate control, small focusing spot, high positioning accuracy, and simple automation.

[0077] Specifically, one or more electrolyte negative electrode infiltration channels 42 are circular, and the connection line of the centers of one or more electrolyte negative electrode infiltration channels 42 forms the negative electrode infiltration channel boundary, and the laser screw harness welding 2 or laser spot welding 3 passes through the negative electrode infiltration channel boundary.

[0078] In addition to the bus plate structure, the embodiment of the present application proposes a battery pack including the above bus plate structure.

Description of Reference Numerals

[0079] 1 Positive electrode bus plate 11 Bus plate body 111 Positive electrode current collecting region 12 Bus plate lead tab 13 Central drain hole 14 Edge drain hole 15 Inner drain hole 16 bosses 17 grooves 18 electrolyte positive electrode infiltration channel 2 laser screw harness welding 21 screw harness welding outer boundary 22 screw harness welding inner boundary 3 laser spot welding 31 spot welding outer boundary 32 spot welding inner boundary 4 negative electrode bus plate 41 intermediate welding spot group 42 electrolyte negative electrode infiltration channel

Claims

1. A bus plate structure, comprising: a positive electrode bus plate (1) including a bus plate main body (11) and a bus plate lead-out tab (12) connected to each other, a central drain hole (13) is provided through the bus plate main body (11) in its thickness direction, A bus plate structure, wherein one surface of the bus plate main body (11) in the thickness direction is a welding surface for welding to the positive tab of the wound electrode group as a whole.

2. The bus plate structure according to claim 1, wherein one or more edge drain holes (14) are provided at intervals on the outer side in the circumferential direction of the bus plate main body (11).

3. The bus plate structure according to claim 2, wherein an inner drain hole (15) is provided through the bus plate main body (11) in its thickness direction, and the inner drain hole (15) is provided adjacent to the central drain hole (13).

4. The bus plate structure according to claim 3, wherein the welding surface of the bus plate main body (11) is welded by laser screw harness welding (2) or laser spot welding (3).

5. In one or more of the laser screw harness weldings (2), a screw harness weld outer boundary (21) and a screw harness weld inner boundary (22) are formed. The screw harness weld outer boundary (21) and the screw harness weld inner boundary (22) are circular and are provided concentric with the central drain hole (13). The center of the inner drain hole (15) is on the screw harness weld outer boundary (21), Or, in one or more of the laser spot weldings (3), a spot weld outer boundary (31) and a spot weld inner boundary (32) are formed. The spot weld outer boundary (31) and the spot weld inner boundary (32) are circular and are provided concentric with the central drain hole (13). The center of the inner drain hole (15) is on the spot weld outer boundary (31). The bus plate structure according to claim 4.

6. On two surfaces of the bus plate main body (11) in the thickness direction, bosses (16) and grooves (17) are provided in a one-to-one correspondence. The grooves (17) and the bosses (16) are of the same shape and are aligned. The bosses (16) are provided on the welding surface, and at least a part of the bosses (16) themselves extends to the edge of the bus plate main body (11). The bus plate structure according to claim 2.

7. One or more of the bosses (16) are provided and are arc-shaped. Both ends of each of the bosses (16) extend to the edge of the bus plate body (11), defining a positive electrode current collection region (111) at the edge portion of the bus plate body (11). One or more of the edge drainage holes (14) are provided in a one-to-one correspondence with one or more of the positive electrode current collection regions (111). The bus plate structure according to claim 6.

8. One or more electrolyte positive electrode infiltration channels (18) penetrate through the bus plate body (11) in its own thickness direction. The bus plate structure according to claim 1.

9. One or more of the electrolyte positive electrode infiltration channels (18) are distributed in an annular array centered on the central drainage hole (13). The region between the central drainage hole (13) and one or more of the electrolyte positive electrode infiltration channels (18) is welded by laser screw harness welding (2) or laser spot welding (3). The bus plate structure according to claim 8.

10. In one or more laser screw harness weldings (2), a screw harness weld outer boundary (21) and a screw harness weld inner boundary (22) are formed. The screw harness weld outer boundary (21) and the screw harness weld inner boundary (22) are circular and are provided concentrically with the central drainage hole (13). One or more of the electrolyte positive electrode infiltration channels (18) are provided outside the screw harness weld outer boundary (21). Or, in one or more of the laser spot weldings (3), a spot weld outer boundary (31) and a spot weld inner boundary (32) are formed. The spot weld outer boundary (31) and the spot weld inner boundary (32) are circular and are provided concentrically with the central drainage hole (13). One or more of the electrolyte positive electrode infiltration channels (18) are provided outside the spot weld outer boundary (31). The bus plate structure according to claim 9.

11. On two surfaces in the thickness direction of the bus plate body (11), the bosses (16) and the grooves (17) are provided in a one-to-one correspondence. The grooves (17) and the bosses (16) are aligned in the same shape. The bosses (16) are provided on the welding surface. One or more of the bosses (16) are provided and are arc-shaped. Both ends of each boss (16) extend to the edge of the bus plate body (11), and an electrolytic solution positive electrode infiltration channel (18) is provided between two adjacent bosses (16). The bus plate structure according to claim 8.

12. An intermediate welding spot group (41) is provided at the center position of one surface in the thickness direction. The welding spots of the intermediate welding spot group (41) are distributed in at least two rows in the first direction. The welding spots in each row are distributed at intervals, and two adjacent rows of the welding spots are provided with shifted positions. The bus plate structure according to claim 1, further comprising a negative electrode bus plate (4).

13. One or more electrolytic solution negative electrode infiltration channels (42) penetrate through the negative electrode bus plate (4) in its own thickness direction. The bus plate structure according to claim 12.

14. One or more of the electrolytic solution negative electrode infiltration channels (42) are distributed in an annular array centered on the intermediate welding spot group (41). The region between two adjacent electrolytic solution negative electrode infiltration channels (42) is welded by laser screw harness welding (2) or laser spot welding (3). The bus plate structure according to claim 13.

15. A battery pack including the bus plate structure according to any one of claims 1 to 14.

Images