Hollow power battery

Abstract

The utility model discloses a hollow power battery which comprises a shell and a hollow piece, the shell is in a hollow column shape with two open ends, a naked battery cell is arranged in the shell, a central hole is formed in the middle of the naked battery cell, the hollow piece comprises a rod part, the rod part is provided with a lower end and an upper end opposite to the lower end, and a bottom soldering lug is arranged at the lower end. The rod part and the bottom soldering lug are provided with through air holes in the axial direction of the rod part, the rod part penetrates through the center hole, the bottom soldering lug is connected with one end of the shell in a welded mode, the other end of the shell is provided with a cover body, and the middle of the cover body is provided with a connecting through hole corresponding to the upper end of the rod part. The upper end of the rod part penetrates through the connecting through hole and is in sealed connection with the cover body, so that the air hole penetrates through the middle part of the hollow power battery. According to the hollow power battery, the shell bottom and the cover body of the power battery are fixed and limited by the hollow part, the rapid reduction of the high temperature in the naked battery core is also assisted, in addition, the hollow power battery is of a hollow structure, a module can directly penetrate through the air holes to be packaged, and the hollow power battery is light and weight-reduced.

Description

Technical Field

[0001] The utility model relates to the field of power batteries, in particular to a hollow power battery. Background Art

[0002] At present, lithium-ion / sodium-ion cylindrical batteries have gradually become the mainstream products in the new energy industry due to their high energy density, good capacity consistency, and support for high-rate charging and discharging. With the popularization of new energy vehicles and the demand for high endurance, more and more manufacturers have begun to pay attention to the rapid cooling and safety of batteries, and at the same time pursue the simplification of the battery structure to achieve weight reduction of the module. Common problems: 1. For the current cylindrical power batteries on the market, the volume and size are getting larger and larger, and the demand for high-rate charging and discharging is getting higher and higher. At present, the module can only be cooled through the battery shell, but the high temperature of the bare battery cells inside the battery cannot directly conduct heat to achieve rapid temperature drop; 2. With the popularization of the current cylindrical power batteries on the market, the complex operating conditions have put forward more new requirements for the battery structure and module diversification; 3. In recent years, some enterprises have proposed to get rid of the traditional single limiting method of the rubber shell for cylindrical batteries and advocate a more direct series PACK, which is also the future direction of a lighter, simpler, and weight-reduced module; 4. For conventional cylindrical lithium batteries, due to the winding tension and the expansion force of the positive and negative electrode sheets in the middle and late stages of the cycle, the positive and negative electrode sheets at the middle and inner circles of the bare battery cells are prone to wrinkling and deformation, resulting in cyclic decline of the battery and affecting the battery life. Summary of the Invention

[0003] The purpose of the utility model is to provide a hollow power battery to solve the problems of low heat dissipation efficiency of the existing power battery and easy wrinkling and deformation of the positive and negative electrode sheets of the power battery.

[0004] To achieve the above purpose, a hollow power battery provided by the utility model includes a housing and a hollow member. The housing is a hollow column with openings at both ends. A bare battery cell is arranged inside the housing. A central hole is arranged in the middle of the bare battery cell. The hollow member includes a rod portion. The rod portion has a lower end and an upper end opposite to the lower end. A bottom solder pad is arranged on the lower end. The rod portion and the bottom solder pad are provided with a through ventilation hole along the axial direction of the rod portion. The rod portion is inserted into the central hole and the bottom solder pad is welded to one end of the housing. A cover body is arranged at the other end of the housing. A connection through hole corresponding to the upper end of the rod portion is arranged in the middle of the cover body. The upper end of the rod portion is inserted into the connection through hole and is hermetically connected to the cover body so that the ventilation hole penetrates through the middle of the hollow power battery.

[0005] Preferably, the rod portion and the bottom solder pad are integrally formed.

[0006] Preferably, an inwardly concave stepped portion is further arranged at the upper end of the rod portion. The cover body is sleeved on the stepped portion and is welded to the stepped portion.

[0007] Preferably, a current collector plate is provided between the bare battery cell and the cover body. The current collector plate includes a disc-shaped body and a connecting piece extending outward from the disc-shaped body. A central through hole is provided in the middle of the disc-shaped body. A positioning hole is provided on the connecting piece corresponding to the central through hole. The positioning hole is located above the central through hole and is coaxially arranged with the central through hole and the connecting through hole. An annular insulating plastic layer is provided on the inner wall of the central through hole. A limiting portion is provided on the insulating plastic layer. The upper end of the rod portion is provided with a matching portion that engages with the limiting portion in a concave-convex manner. The rod portion passes through the insulating plastic layer, and the limiting portion and the matching portion are engaged and limitedly connected. The matching portion is located below the stepped portion.

[0008] Preferably, the limiting portion is a convex portion protruding inward from the insulating plastic layer. The matching portion is provided at the upper end of the rod portion. The matching portion is a groove recessed inward from the rod portion, and the groove extends to the upper end face of the rod portion.

[0009] Preferably, there are at least two limiting portions, and at least two limiting portions are evenly distributed on the inner wall of the insulating plastic layer. Correspondingly, there are at least two matching portions, and at least two matching portions are evenly distributed on the outer wall of the rod portion.

[0010] Preferably, a pole column and a pressure relief valve are further provided on the cover body. The pole column and the pressure relief valve are respectively arranged on both sides of the connecting through hole.

[0011] Preferably, a first liquid injection hole is further provided on the pole column. A second liquid injection hole is provided at the end of the connecting piece corresponding to the first liquid injection hole. The bottom of the pole column is welded to the end of the connecting piece, and the first liquid injection hole and the second liquid injection hole are in alignment and communication.

[0012] Preferably, a bearing step extending inward from the bottom end of the housing is provided at the bottom end of the housing. The bottom solder pad is arranged on the bearing step and is welded to the bearing step.

[0013] Preferably, a recessed portion recessed toward the inside of the housing is provided on the bottom solder pad. The recessed portion is welded to the full tab on the bare battery cell close to the bottom solder pad.

[0014] Compared with the prior art, the utility model realizes the fixation and limitation of the bottom shell and the cover body of the power battery by arranging a hollow part with through ventilation holes, passing the rod part of the hollow part through the bare battery cell and connecting it with the cover body, and connecting the bottom solder pad with the shell, and also assists in quickly transferring the heat inside the bare battery cell to achieve a rapid temperature drop. In addition, the hollow power battery realizes a hollow structure, and the module can be directly encapsulated through the ventilation holes, which is simple, light and reduces weight; the rod part is arranged in the bare battery cell to achieve axial positioning, offsetting the winding tension of the positive and negative electrode plates at the middle and inner circles of the bare battery cell and the expansion force of the positive and negative electrode plates in the later stage of the cycle, improving the structural stability and cycle life of the hollow power battery. Brief Description of the Drawings

[0015] Figure 1 It is a structural diagram of the hollow power battery according to an embodiment of the utility model from one angle.

[0016] Figure 2 It is a structural diagram of the hollow power battery according to an embodiment of the utility model from another angle.

[0017] Figure 3 It is a structural diagram of the hollow part in the embodiment of the utility model.

[0018] Figure 4 It is Figure 3 The enlarged view of the C position in

[0019] Figure 5 It is a structural diagram of the current collector plate in the embodiment of the utility model, at this time, the connecting piece is not bent.

[0020] Figure 6 It is a structural diagram of the current collector plate in the embodiment of the utility model, at this time, the connecting piece is bent.

[0021] Figure 7 It is Figure 2 The sectional view taken along the A-A direction in

[0022] Figure 8 It is Figure 2 The sectional view taken along the B-B direction in

[0023] Figure 9 It is Figure 8 The enlarged view of the D position in Detailed Embodiment

[0024] In order to describe in detail the technical content, structural features and achieved effects of the utility model, the following is described in detail in conjunction with the embodiments and with reference to the drawings.

[0025] Such as Figures 1 to 9As shown in the figure, the utility model discloses a hollow power battery 10, which includes a housing 1 and a hollow member 2. The housing 1 is a hollow column with openings at both ends. A bare battery cell 6 is arranged inside the housing 1. A central hole is provided in the middle of the bare battery cell 6. The hollow member 2 includes a rod portion 21. The rod portion 21 has a lower end and an upper end 211 opposite to the lower end. A bottom solder tab 22 is provided on the lower end. The rod portion 21 and the bottom solder tab 22 are provided with a through ventilation hole 23 along the axial direction of the rod portion 21. The rod portion 21 is inserted into the central hole, and the bottom solder tab 22 is welded to one end of the housing 1. A cover 3 is arranged at the other end of the housing 1. A connection through hole 31 corresponding to the upper end 211 of the rod portion 21 is provided in the middle of the cover 3. The upper end 211 of the rod portion 21 is inserted into the connection through hole 31 and is hermetically connected to the cover 3 so that the ventilation hole 23 penetrates through the middle of the hollow power battery 10. Specifically, the power battery 10 is a cylindrical power battery 10. The rod portion 21 and the bottom solder tab 22 are integrally formed by stamping and stretching. Of course, in some other embodiments, the rod portion 21 and the bottom solder tab 22 can also be welded together. The rod portion 21 is inserted into the central hole of the bare battery cell 6, and the ventilation hole 23 penetrates through the middle of the power battery 10, which not only fixes and positions the bottom of the shell and the cover 3, but also assists in achieving rapid heat transfer of the high temperature inside the bare battery cell 6, realizing rapid temperature drop at high temperature.

[0026] In the embodiment of the utility model, by providing the hollow member 2 with a through ventilation hole 23, inserting the rod portion 21 of the hollow member 2 into the bare battery cell 6 and connecting it to the cover 3, and connecting the bottom solder tab 22 to the housing 1, the hollow member 2 realizes the fixation and positioning of the bottom of the shell and the cover 3 of the power battery, and also assists in achieving rapid heat transfer of the high temperature inside the bare battery cell 6, realizing rapid temperature drop at high temperature. In addition, the hollow power battery 10 realizes a hollow structure, and the module can directly penetrate through the ventilation hole 23 for module packaging, which is simple, light and weight-reducing; the rod portion 21 is inserted into the bare battery cell 6 to realize axial positioning, offsetting the winding tension of the positive and negative plates at the positions of the middle and inner circles of the bare battery cell 6 and the expansion force of the positive and negative plates in the middle and late stages of the cycle, improving the structural stability and cycle life of the hollow power battery 10.

[0027] In the embodiment of the utility model, the upper end 211 of the rod portion 21 is further provided with a stepped portion 212 that is recessed inward. The cover 3 is sleeved on the stepped portion 212 and is welded to the stepped portion 212. Specifically, as Figure 3 and Figure 4 shown, the stepped portion 212 is used to limit the cover 3 to install and position the rod portion 21 and the cover 3. The stepped portion 212 has a stepped surface 2121 and a connection surface 2122 extending from the stepped surface 2121 to the end surface of the upper end 211 of the rod portion 21. The connection surface 2122 is attached to the inner wall of the connection through hole 31 and is laser welded.

[0028] In the embodiment of the present utility model, a current collector plate 4 is provided between the bare battery cell 6 and the cover body 3. The current collector plate 4 includes a disc-shaped body 41 and a connecting piece 42 extending outward from the disc-shaped body 41. A central through hole 411 is provided in the middle of the disc-shaped body 41. A positioning hole 421 is provided on the connecting piece 42 corresponding to the central through hole 411. The positioning hole 421 is located above the central through hole 411 and the positioning hole 421, the central through hole 411 and the connecting through hole 31 are coaxially arranged; an annular insulating plastic layer 43 is provided on the inner wall of the central through hole 411. A limiting portion 431 is provided on the insulating plastic layer 43. A matching portion 213 that is in concave-convex fit with the limiting portion 431 is provided at the upper end 211 of the rod portion 21. The rod portion 21 passes through the insulating plastic layer 43 and the limiting portion 431 is in limiting connection with the matching portion 213. The matching portion 213 is located below the stepped portion 212. Specifically, as Figures 1 to 9 shown, the current collector plate 4 is a positive current collector plate. The insulating plastic layer 43 is formed in the middle of the disc-shaped body 41 by injection molding. At least two welding grooves 412 are provided on the disc-shaped body 41. The at least two welding grooves 412 are symmetrically distributed. The welding grooves 412 can be three evenly distributed ones. The disc-shaped body 41 is welded and connected to the full pole ear corresponding to the positive current collector plate on the bare battery cell 6 through at least two welding grooves 412, and the connection is stable. As Figure 5 and Figure 6 shown, when assembled, the connecting piece 42 can be folded and stacked on the disc-shaped body 41 so that the central through hole 411 and the positioning hole 421 are correspondingly arranged, so that the rod portion 21 passes through the central through hole 411 and the positioning hole 421. The hollow member 2 and the disc-shaped body 41 are in limiting connection through the insulating plastic layer 43, so as to realize the circumferential anti-rotation of the bare battery cell 6 while ensuring the electrical isolation between the hollow member 2 and the current collector plate 4, completely avoiding the direct impact of a large torque of the bare battery cell 6 on the internal electrical connection position of the battery, and finally avoiding the occurrence of an open circuit of the power battery 10, and at the same time avoiding the leakage of the power battery with a sealing structure.

[0029] In the embodiment of the present utility model, the limiting portion 431 is a convex portion protruding toward the inside of the insulating plastic layer 43. The matching portion 213 is provided at the upper end 211 of the rod portion 21. The matching portion 213 is a groove recessed toward the inside of the rod portion 21. The groove extends to the end face of the upper end 211 of the rod portion 21 for easy assembly. Specifically, as Figure 3 and Figure 9 shown, the matching portion 213 is a groove recessed from the outer surface of the hollow member 2 toward the inside. The circumferential anti-rotation of the bare battery cell 6 is realized through the concave-convex fit between the groove and the convex portion, and the design is ingenious.

[0030] In the embodiment of the present utility model, there are at least two limiting portions 431. The at least two limiting portions 431 are evenly distributed on the inner wall of the insulating plastic layer 43. The corresponding matching portions 213 are at least two. The at least two matching portions 213 are evenly distributed on the outer wall of the rod portion 21. Specifically, asFigures 4 to 5 As shown, there are four limiting parts 431 and four mating parts 213. By evenly distributing a plurality of limiting parts 431 and a plurality of mating parts 213, a better and more stable limiting effect can be achieved.

[0031] In the embodiment of the present utility model, the sizes of the middle through hole 411 and the alignment hole 421 are the same. Specifically, by setting the size of the alignment hole 421 to be the same as or close to the size of the middle through hole 411, the hollow part 2 and the connecting piece 42 can be made not to contact each other, ensuring the electrical isolation between the hollow part 2 and the connecting piece 42.

[0032] In the embodiment of the present utility model, widening parts 422 are provided on both sides of the alignment hole 421, and the side surface of the widening part 422 is in an outwardly convex arc shape. Specifically, as Figure 5 shown, the provision of the widening part 422 ensures the current-carrying area of the connecting piece 42 at the alignment hole 421, making the electrical performance of the hollow power battery 10 better.

[0033] In the embodiment of the present utility model, as Figure 2 , Figure 5 and Figure 7 shown, a pole column 5 and a pressure relief valve 7 are further provided on the cover body 3, and the pole column 5 and the pressure relief valve 7 are respectively arranged on both sides of the connection through hole 31. Specifically, a scale line 71 is provided on the pressure relief valve 7 to relieve pressure when the internal pressure of the power battery is too high. A first liquid injection hole 51 is further provided on the pole column 5. A second liquid injection hole 423 is provided at the end of the connecting piece 42 corresponding to the first liquid injection hole 51. The bottom of the pole column 5 is welded to the end of the connecting piece 42, and the first liquid injection hole 51 and the second liquid injection hole 423 are in alignment and communication.

[0034] In the embodiment of the present utility model, a bearing step 11 extending towards the inside of the housing 1 is provided at the bottom end of the housing 1, and the bottom solder pad 22 is arranged on the bearing step 11 and welded to the bearing step 11. Specifically, as Figure 3 and Figure 7 shown, the bottom solder pad 22 is arranged on the bearing step 11 and laser welded to the bearing step 11, which is convenient for welding.

[0035] In the embodiment of the present utility model, a recessed part 221 recessed towards the inside of the housing 1 is provided on the bottom solder pad 22, and the recessed part 221 is welded to the full pole ear on the bare battery cell 6 close to the bottom solder pad 22. Specifically, the thickness of the bottom solder pad 22 is less than the thickness of the housing 1. By directly welding the bottom solder pad 22 to the full pole ear at the bottom of the bare battery cell 6, an additional negative current collector plate does not need to be prepared, effectively saving process steps and cost. Moreover, a relatively thick bearing step 11 is used to support the hollow power battery 10, and the hollow power battery 10 has good strength.

[0036] The assembly method of the hollow power battery 10 of the present utility model is as follows: First, the bottom solder tab 22 is adapted to the bearing step 11 of the housing 1 and welded and sealed. Then, the upper end 211 of the all-pole ear of the bare battery cell 6 and the welding groove 412 of the current collector plate 4 are fixed by laser welding. The bare battery cell 6 is inserted into the housing 1, and the limiting part 431 of the hollow part 2 and the matching part 213 of the insulating plastic layer 43 of the current collector plate 4 are connected in a limiting manner. Then, a fixture is used to hold the bare battery cell 6 against, and the all-pole ear at the lower end of the bare battery cell 6 is attached to the recessed part 221 of the bottom solder tab 22 and fixed by laser welding. Then, the connecting piece 42 of the current collector plate 4 is attached to the bottom surface of the pole post 5 on the cover body 3 and welded and fixed. Then, the connecting piece 42 is bent at a preset position. The cover body 3 and the shell opening of the housing 1 are adapted, and at the same time, the step part 212 of the hollow part 2 limits the cover body 3, and laser welding is respectively used for sealing and fixing.

[0037] The above-disclosed are only the preferred examples of the present utility model. Of course, the scope of rights of the present utility model cannot be limited thereby. Therefore, equivalent changes made according to the scope of the patent application of the present utility model still fall within the scope covered by the present utility model.

Claims

1. A hollow power battery, characterized in that: It comprises a shell and a hollow part, wherein the shell is in a hollow column shape with openings at both ends, a bare battery cell is arranged in the shell, a center hole is arranged in the middle of the bare battery cell, and the hollow part comprises a rod portion, wherein the rod portion has a lower end and an upper end opposite to the lower end, a bottom welding piece is arranged on the lower end, and a through air hole is arranged on the rod portion and the bottom welding piece along the axial direction of the rod portion, the rod portion is penetrated in the center hole and the bottom welding piece is welded to one end of the shell, a cover body is arranged at the other end of the shell, a connecting through hole is arranged in the middle part of the cover body corresponding to the upper end of the rod portion, the upper end of the rod portion is penetrated in the connecting through hole and is sealed with the cover body so that the air hole passes through the middle part of the hollow power battery.

2. The hollow power battery according to claim 1, characterized in that: The rod portion and the bottom welding sheet are integrally formed.

3. The hollow power battery according to claim 1, characterized in that: The upper end of the rod portion is also provided with an inwardly recessed step portion, and the cover body is sleeved on the step portion and is welded to the step portion.

4. The hollow power battery according to claim 3, characterized in that: A current collecting plate is provided between the bare battery cell and the cover body, and the current collecting plate includes a disc-shaped body and a connecting piece extending outward from the disc-shaped body, a central through hole is provided in the central part of the disc-shaped body, and an alignment hole is provided on the connecting piece corresponding to the central through hole, the alignment hole is provided above the central through hole and the alignment hole is coaxially arranged with the central through hole and the connecting through hole; an annular insulating plastic layer is provided on the inner wall of the central through hole, a limiting portion is provided on the insulating plastic layer, a matching portion that matches the limiting portion in a concave-convex manner at the upper end of the rod portion is provided, the rod portion is penetrated in the insulating plastic layer and the limiting portion is matched with the matching portion in a limiting manner, and the matching portion is located below the step portion.

5. The hollow power battery according to claim 4, characterized in that: The limiting portion is a protrusion protruding toward the inner side of the insulating plastic layer, the matching portion is arranged at the upper end of the rod, the matching portion is a groove sunken toward the inside of the rod, and the groove extends to the upper end surface of the rod.

6. The hollow power battery according to claim 5, characterized in that: There are at least two limiting parts, which are evenly distributed on the inner wall of the insulating plastic layer. There are correspondingly at least two matching parts, which are evenly distributed on the outer wall of the rod.

7. The hollow power battery according to claim 4, characterized in that: The cover body is also provided with a pole and a pressure relief valve, and the pole and the pressure relief valve are respectively arranged on both sides of the connecting through hole.

8. The hollow power battery according to claim 7, characterized in that: The pole is also provided with a first injection hole, and the end of the connecting piece is provided with a second injection hole corresponding to the first injection hole. The bottom of the pole is welded to the end of the connecting piece, and the first injection hole and the second injection hole are aligned and connected.

9. The hollow power battery according to claim 1, characterized in that: The bottom end of the shell is provided with a bearing step extending toward the inner side of the shell, and the bottom welding sheet is provided on the bearing step and is welded to the bearing step.

10. The hollow power battery according to claim 9, characterized in that: The bottom welding sheet is provided with a recessed portion recessed toward the inside of the shell, and the recessed portion is welded and connected to the full pole tab on the bare battery cell close to the bottom welding sheet.

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