power battery

Abstract

This application provides a power battery with a top cover structure including a top cover sheet with a first through hole; an upper injection molded part with a second through hole; a sealing ring located in the second through hole and penetrating the first through hole; and a composite electrode post penetrating the sealing ring. By setting the inner diameter of the second through hole to be smaller than the outer diameter of the first sealing part, and the lower part of the first sealing part overlapping with the upper injection molded part, the first sealing part is supported by the upper injection molded part. The inner diameter of the first sealing part of the sealing ring is smaller than the outer diameter of the first base part, and the first base part overlaps with the upper part of the first sealing part, so that the first sealing part supports the first base part. Therefore, when the composite electrode post is riveted, the downward force of the first base part of its aluminum base directly acts on the sealing ring, thereby reducing the stress on the copper-aluminum joint surface of the composite electrode post and avoiding the risk of fracture of the copper-aluminum joint surface under stress.

Description

Technical Field

[0001] This invention relates to the technical field of power batteries, specifically to a power battery. Background Technology

[0002] Power batteries serve as the power source for new energy vehicles, and include a top cover structure. In related technologies, the terminal post is a component in the top cover structure that connects the inside and outside of the battery. The negative terminal post, to simultaneously accommodate the welding of the internal tabs and the external busbar, is typically a copper-aluminum composite terminal post. The copper end of the composite terminal post is located inside the cell and welded to the tabs or adapter plates; the aluminum end is located outside the cell and welded to the busbar. The connection between the copper and aluminum parts of the terminal post is achieved through friction welding or direct processing of the composite sheet material.

[0003] However, since copper is harder than aluminum, when riveting the copper end of the composite electrode, the copper-aluminum interface of the composite electrode is subjected to stress, which may lead to the risk of the copper-aluminum interface breaking.

[0004] In summary, in view of the problem of the risk of copper-aluminum bonding surface fracture in composite poles in related technologies, this application provides a power battery to improve this problem. Summary of the Invention

[0005] The embodiments of the present invention provide a power battery that can improve the technical problem of the risk of fracture at the copper-aluminum junction of composite electrodes.

[0006] An embodiment of the present invention provides a power battery, including a top cover structure, the top cover structure comprising:

[0007] A top cover plate, wherein a first through hole is provided on the top cover plate;

[0008] An upper injection molded part is disposed above the top cover plate, and a second through hole is provided on the upper injection molded part;

[0009] A sealing ring is disposed in the second through hole and passes through the first through hole, the sealing ring including a first sealing part in an annular shape;

[0010] A composite electrode post includes an aluminum base and a copper base connected to each other, the composite electrode post passing through the sealing ring, and the aluminum base includes at least a first base portion;

[0011] Wherein, the inner diameter of the second through hole is smaller than the outer diameter of the first sealing part, and the lower part of the first sealing part overlaps with the upper injection molded part; the inner diameter of the first sealing part is smaller than the outer diameter of the first base part, and the first base part overlaps with the upper part of the first sealing part.

[0012] In one embodiment, the sealing ring includes a cylindrical second sealing portion, the first sealing portion and the second sealing portion are integrally formed, and the second sealing portion at least covers the copper-aluminum bonding surface of the composite pole.

[0013] In one embodiment, a first chamfer is formed on the inner side of the upper end of the first sealing portion, and the first chamfer cooperates with the outer side of the lower end of the first base portion.

[0014] In one embodiment, the aluminum base includes a first column portion located below the first base portion, and the outer diameter of the first base portion is larger than the outer diameter of the first column portion; the copper base includes a second base portion and a second column portion, the outer diameter of the second base portion is equal to the outer diameter of the first column portion, and the outer diameter of the second base portion is larger than the outer diameter of the second column portion.

[0015] In one embodiment, the second sealing portion includes a first sub-sealing portion and a second sub-sealing portion, wherein the inner diameter of the first sub-sealing portion is larger than the inner diameter of the second sub-sealing portion, the first sub-sealing portion covers the copper-aluminum mating surface, and the second sub-sealing portion fits into the second columnar portion.

[0016] In one embodiment, the top cover structure includes a lower injection molded part located below the top cover sheet, the lower injection molded part having a third through hole, the sealing ring passing through the third through hole, and the bottom of the sealing ring being flush with the bottom of the lower injection molded part.

[0017] In one embodiment, the upper injection molded part has a first receiving cavity on the side away from the top cover sheet, and the second through hole is disposed in the first receiving cavity; the lower injection molded part has a second receiving cavity on the side away from the top cover sheet, and the third through hole is disposed in the second receiving cavity.

[0018] In one embodiment, the top cover structure further includes:

[0019] A pole terminal is located within the first receiving cavity, and a fourth through hole is provided on the pole terminal;

[0020] The pole base plate is located inside the second receiving cavity, and a fifth through hole is provided on the pole base plate.

[0021] In one embodiment, the composite pole extends through the first through hole, the second through hole, the third through hole, the fourth through hole, and the fifth through hole to connect with the pole terminal and the pole base plate.

[0022] In one embodiment, the power battery further includes a casing and a battery cell, the battery cell being disposed within the casing; the top cover structure is disposed at the open end of the casing.

[0023] The beneficial effects of embodiments of the present invention are as follows: This application provides a power battery, the top cover structure including a top cover sheet with a first through hole; an upper injection molded part with a second through hole; a sealing ring located in the second through hole and penetrating the first through hole; and a composite electrode post penetrating the sealing ring. By setting the inner diameter of the second through hole to be smaller than the outer diameter of the first sealing part, and the lower part of the first sealing part overlapping with the upper injection molded part, the first sealing part is supported by the upper injection molded part; the inner diameter of the first sealing part of the sealing ring is smaller than the outer diameter of the first base part, and the first base part overlaps with the upper part of the first sealing part, so that the first sealing part supports the first base part. Therefore, when the composite electrode post is riveted, the downward force of the first base part of its aluminum base directly acts on the sealing ring, thereby reducing the stress on the copper-aluminum joint surface of the composite electrode post and avoiding the risk of fracture of the copper-aluminum joint surface under stress. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is an exploded perspective view of the top cover structure provided in an embodiment of the present invention;

[0026] Figure 2 This is a cross-sectional structural diagram of the top cover structure provided in an embodiment of the present invention;

[0027] Figure 3 yes Figure 2 A partial cross-sectional view of point A in the cross-section of the roof structure;

[0028] Figure 4 This is a front view of the composite pole provided in an embodiment of the present invention;

[0029] Figure 5 This is a cross-sectional view of the sealing ring provided in an embodiment of the present invention. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Furthermore, it should be understood that the specific embodiments described herein are only for illustration and explanation of the present invention and are not intended to limit the present invention. In the present invention, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in actual use or operation, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.

[0031] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features.

[0032] This application provides a power battery, which includes a top cover structure. Figure 1 An exploded view of the top cover structure provided in this application. Figure 2 A cross-sectional view of the roof structure provided for this application. Figure 3 for Figure 2 A magnified view of a section section. For example... Figures 1-3 As shown, the top cover structure includes a top cover plate 10 with a groove 61 and a first through hole 21 within the groove 61; an upper injection molded part 11, positioned above the top cover plate 10, specifically, at least partially located within the groove 61. A first receiving cavity is provided on the side of the upper injection molded part 11 away from the top cover plate 10, and a second through hole 22 is provided within the first receiving cavity. A lower injection molded part 12 is located below the top cover plate 10, and a second receiving cavity is provided on the side of the lower injection molded part 12 away from the top cover plate 10, and a third through hole 23 is provided within the second receiving cavity. A sealing ring 13 is disposed within the second through hole 22 and penetrates both the first through hole 21 and the third through hole 23; furthermore, the bottom of the sealing ring 13 is flush with the bottom of the second receiving cavity. A composite pole 14 is located within the sealing ring 13 and penetrates the sealing ring 13.

[0033] It should be noted that the main function of the groove 61 is to limit movement. Furthermore, a limiting recess 62 is provided around the first through hole, and the second through hole 22 of the upper injection molded part 11 is fitted into the limiting recess 62.

[0034] It should be noted that the upper injection molded part 11 and the lower injection molded part 12 are made of insulating plastic to insulate the composite electrode post 14, which serves as the negative electrode post, from the top cover plate 10. This reduces the current in the circuit when a short circuit occurs in the power battery. Optionally, the materials of the injection molded parts 11 and 12 include one or a combination of PP, PPS, TPU, or TPE materials. PP, PPS, TPU, and TPE materials all possess high temperature resistance, corrosion resistance, superior mechanical properties, and insulation properties, which help improve the service life of the upper injection molded part 11 and the lower injection molded part 12, thereby improving the quality of the power battery. Furthermore, they have good environmental performance and fire resistance, better meeting the environmental requirements of the new energy vehicle sector.

[0035] It needs to be explained, such as Figure 3 , Figure 4 As shown, the composite electrode 14 includes a copper base 142 and an aluminum base 141 connected to each other, wherein the aluminum base 141 is located above the copper base 142. The copper base 142 and the aluminum base are typically connected by friction welding or by pressing a copper-aluminum composite plate. The copper base 142 is connected to the negative current collector inside the battery cell, and the aluminum base 141 is connected to the external circuit of the battery. This overcomes the problems of high weight and high cost caused by using pure copper as the negative electrode in the current top cover structure, reducing the weight of the battery and lowering the cost while ensuring battery performance.

[0036] However, since copper is harder than aluminum, when riveting the copper end of the composite pole 14, the composite position of the aluminum base 141 and the copper base 142 of the composite pole 14, i.e. the copper-aluminum interface, is prone to breakage under stress, thus affecting the performance of the battery cell.

[0037] Therefore, by optimizing the structure of the sealing ring 13, this application ensures that the reaction force of the interference fit of the sealing ring 13 will not directly act on the copper-aluminum joint surface of the composite pole 14, thereby reducing the risk of copper-aluminum joint surface breakage.

[0038] Specifically, in this embodiment, such as Figures 3-5As shown, the sealing ring 13 includes a first sealing portion 131 in an annular shape, and the aluminum base 141 includes a first base portion 31 and a first column portion 41 below the first base portion 31. The outer diameter of the first column portion 41 is smaller than the outer diameter of the first base portion 31. The second through hole 22 is provided with an inner diameter smaller than the outer diameter of the first sealing portion 131, and the upper part of the first sealing portion 131 overlaps with the upper injection molded part 11, so that the first sealing portion 131 is supported by the upper injection molded part 11. The inner diameter of the first sealing portion 131 is smaller than the outer diameter of the first base portion 31, and the first base portion 31 overlaps with the upper part of the first sealing portion 131, so that the first sealing portion 131 supports the first base portion 31. Therefore, when the composite pole 14 is riveted, the downward force of the first base portion 31 of the aluminum base portion 141 directly acts on the sealing ring 13, and the force acting on the sealing ring 13 is dispersed through the upper injection molded part 11, thereby reducing the force on the copper-aluminum joint surface during the riveting process of the composite pole 14 and avoiding the risk of the copper-aluminum joint interface breaking under stress.

[0039] Furthermore, a first chamfer 51 is formed on the inner side of the upper end of the first sealing part 131 at the contact position with the first base part 31. The first chamfer 51 creates a slope on the inner side of the upper end of the first sealing part 131, preferably an obtuse angle. During the riveting of the composite pole 14, the first base part 31 acts on the position of the first chamfer 51, thereby providing a buffering effect without damaging the structure of the sealing ring 13.

[0040] Furthermore, at the contact position between the first sealing portion 131 and the upper injection molded part 11, i.e., on the outer side of the lower end of the first sealing portion 131, a second chamfer 52 is formed. The second chamfer 52 is a slope formed on the outer side of the lower end of the first sealing portion 131. Correspondingly, the upper injection molded part 11 forms a third chamfer at the edge of the first through hole 21 that cooperates with the second chamfer 52. The third chamfer and the second chamfer 52 cooperate with each other, which facilitates installation, buffers the force, and also serves as a guide. Preferably, the size of the third chamfer is smaller than the size of the second chamfer 52.

[0041] In this embodiment, the sealing ring 13 further includes a cylindrical second sealing part 132. The first sealing part 131 and the second sealing part 132 are integrally formed. The second sealing part 132 includes at least the copper-aluminum bonding surface of the composite electrode post 14 to prevent the copper-aluminum bonding surface from contacting the electrolyte and causing an oxidation-reduction reaction, thereby extending the service life of the composite electrode post 14.

[0042] In this embodiment, the copper base 142 includes a second base portion 32 and a second column portion 42, which are integrally formed. The outer diameter of the second base portion 32 is equal to the outer diameter of the first column portion 41, and the upper end face of the second base portion 32 contacts the lower end face of the first column portion 41 to form a copper-aluminum bonding surface. The outer diameter of the second base portion 32 is larger than the outer diameter of the second column portion 42. To achieve a good sealing effect, the second sealing portion 132 is provided with a cylindrical first sub-sealing portion 1321 and a second sub-sealing portion 1322, the inner diameter of the first sub-sealing portion 1321 being larger than the inner diameter of the second sub-sealing portion 1322. The first sub-sealing portion 1321 covers the copper-aluminum bonding surface, and the second sub-sealing portion 1322 fits into the second column portion 42.

[0043] It should be noted that the sealing ring 13 in the embodiment of this application is made of an elastic material that is resistant to acids and alkalis and high temperatures.

[0044] In this embodiment, the aluminum base 141 further includes a third base portion 33 and a third pillar portion 43 located above the first base portion 31, with the third pillar portion 43 situated between the first base portion 31 and the third base portion 33. The third base portion 33, the third pillar portion 43, the first base portion 31, and the first pillar portion 41 are integrally formed.

[0045] Furthermore, in this embodiment, the top cover structure also includes an electrode terminal 15 and an electrode base plate 16. The electrode terminal 15 is located within the first receiving cavity, and a fourth through hole 24 is provided on the electrode terminal 15. The electrode base plate 16 is located within the second receiving cavity, and a fifth through hole 25 is provided on the electrode base plate 16. The composite electrode 14 passes through the first through hole 21, the second through hole 22, the third through hole 23, the fourth through hole 24, and the fifth through hole 25 to connect with the electrode terminal 15 and the electrode base plate 16.

[0046] It should be noted that in this application, the composite terminal 14 and its mating sealing ring 13 and other components are in two sets. However, it should be understood that the number of composite terminal 14 and its mating sealing ring 13 and other components may be one set, two sets, or other quantities; this application does not specifically limit this. In actual production, one set, two sets, or other quantities can be selected based on the battery charge / discharge rate. Two sets can be selected for a high charge / discharge rate, thus increasing the current carrying capacity of the positive and negative terminals. One set can be selected for a low charge / discharge rate, which, under certain conditions, can reduce the weight of the top cover structure while reducing the number of structural components. Here, "high" and "low" are relative concepts.

[0047] In this embodiment, in order to improve the safety performance of the power battery and facilitate battery assembly, the top cover plate 10 is also provided with an injection hole 26. The injection hole 26 penetrates the top cover plate 10, and electrolyte can be injected into the power battery through the injection hole 26.

[0048] Furthermore, the power battery provided in this application also includes a casing, a battery cell, and a top cover structure as described in any of the above embodiments. The battery cell is disposed within the casing, and the top cover structure is disposed at the open end of the casing. In one embodiment, the power battery is a lithium battery. By using the top cover structure provided in the embodiments of this application, the power battery can have more stable performance and a longer service life.

[0049] The embodiments of the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A power battery, characterized in that, Includes a top cover structure, the top cover structure comprising: A top cover plate, wherein a first through hole is provided on the top cover plate; An upper injection molded part is disposed above the top cover plate, and a second through hole is provided on the upper injection molded part; A sealing ring is disposed in the second through hole and passes through the first through hole, the sealing ring including a first sealing part in an annular shape; A composite electrode post includes an aluminum base and a copper base connected to each other, the composite electrode post passing through the sealing ring, and the aluminum base includes at least a first base portion and a first column portion located below the first base portion; Wherein, the inner diameter of the second through hole is smaller than the outer diameter of the first sealing part, and the lower part of the first sealing part overlaps with the upper injection molded part so that the first sealing part is supported by the upper injection molded part; the inner diameter of the first sealing part is smaller than the outer diameter of the first base part, and the first base part overlaps with the upper part of the first sealing part so that the first sealing part supports the first base part. The copper base includes a second base portion and a second column portion. The upper end face of the second base portion and the lower end face of the first column portion are in contact to form a copper-aluminum bonding surface. The outer diameter of the second base portion is larger than the outer diameter of the second column portion. The sealing ring further includes a cylindrical second sealing part, and the first sealing part and the second sealing part are integrally formed; the second sealing part includes a first sub-sealing part and a second sub-sealing part, the inner diameter of the first sub-sealing part is larger than the inner diameter of the second sub-sealing part, wherein the first sub-sealing part covers the copper-aluminum bonding surface, the second sub-sealing part fits into the second column part, and the second base part overlaps the second sub-sealing part.

2. The power battery as described in claim 1, characterized in that, The outer diameter of the first base portion is greater than the outer diameter of the first column portion; the outer diameter of the second base portion is equal to the outer diameter of the first column portion.

3. The power battery as described in claim 1, characterized in that, The top cover structure includes a lower injection molded part located below the top cover sheet. The lower injection molded part is provided with a third through hole. The sealing ring passes through the third through hole, and the bottom of the sealing ring is flush with the bottom of the lower injection molded part.

4. The power battery as described in claim 3, characterized in that, The upper injection molded part has a first receiving cavity on the side away from the top cover plate, and the second through hole is disposed in the first receiving cavity; the lower injection molded part has a second receiving cavity on the side away from the top cover plate, and the third through hole is disposed in the second receiving cavity.

5. The power battery as described in claim 4, characterized in that, The top cover structure also includes: A pole terminal is located within the first receiving cavity, and a fourth through hole is provided on the pole terminal; The pole base plate is located inside the second receiving cavity, and a fifth through hole is provided on the pole base plate.

6. The power battery as described in claim 5, characterized in that, The composite pole extends through the first through hole, the second through hole, the third through hole, the fourth through hole, and the fifth through hole to connect with the pole terminal and the pole base plate.

7. The power battery according to any one of claims 1 to 6, characterized in that, The power battery also includes a casing and a battery cell, with the battery cell disposed inside the casing; the top cover structure is disposed at the open end of the casing.

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