Method for manufacturing the top cover structure of a power battery by injection molding

Abstract

To provide a top cover injection molding structure of a power battery of which the structure is strong and the cost of large-scale manufacturing is lower.SOLUTION: Regarding a top cover injection molding structure for a power battery, the top cover injection molding structure includes a top cover plate and an electrode pole assembly. An electrode pole hole for fitting the electrode pole assembly is provided in the top cover plate, a plurality of bosses for connection is provided in an outer periphery of the electrode pole hole, and the electrode pole assembly includes a first molding member 21, an electrode pole 22 and a seal member 23. After the electrode pole is assembled in the electrode pole hole via the seal member, injection molding is performed in an outer periphery of the electrode pole, thereby obtaining the first molding member. The electrode pole is fixed and connected to the top cover plate by irregularly fitting the first molding member with the bosses for connection, and the electrode pole and the top cover plate are insulated by the first molding member and the seal member. The top cover injection molding structure strengthens the connection, reduces cost of manufacture and is useful for promoting the applications of a lithium battery.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention belongs to the field of lithium batteries, specifically: Method for manufacturing the top cover structure of a power battery by injection molding Regarding. [Background technology]

[0002] Power batteries are an important component of new energy vehicles, and most of the existing new energy batteries use lithium-ion batteries as their power batteries. In addition to the main components such as cells and BMS, the battery case structure of a power lithium battery is also one of the factors related to its safety. Here, the poles are also components of the battery module, and not only are they connected to the positive and negative electrodes of the cells in the module to conduct electricity, but they also require corresponding structural strength and sealing requirements to meet the application requirements of new energy vehicles.

[0003] However, the top covers of existing batteries have a complicated structure and are expensive to manufacture, limiting the large-scale application of lithium batteries. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] China Patent Application Publication No. 110048037 Summary of the Invention [Problem to be solved by the invention]

[0005] The object of the present invention is to provide a robust structure and lower cost of large scale manufacture. Method for manufacturing the top cover structure of a power battery by injection molding The purpose of this project is to provide [Means for solving the problem]

[0006] In order to achieve the above object, the solutions adopted in the present invention are as follows:

[0007] Method for manufacturing the top cover structure of a power battery by injection moldinga top cover plate and a pole assembly; A pole hole is provided so as to penetrate through the top cover plate, a plurality of connection bosses are provided on the outer periphery of the pole hole, and a first uneven member is formed on the connection bosses; the pole assembly is fitted to the top cover plate to form a positive pole or a negative pole, the pole assembly includes a first molded member, a pole and a sealing member, the pole is assembled in a pole hole, the sealing member is provided between the pole and the top cover plate, the first molded member is formed by injection molding on the outer periphery of the pole, a boss cavity for receiving the connecting boss is molded in the first molded member, a second uneven member is molded in the boss cavity, the first molded member is connected to the top cover plate by uneven engagement between the first uneven member and the second uneven member, and thus the pole and the sealing member are fixed to the top cover plate by the first molded member, Here, the electrode post and the top cover plate are insulated from each other by the first molding member and the sealing member.

[0008] In one embodiment of the present application, a predetermined pressure is applied to the pole during injection molding and cooling of the first molded member, so that the seal member is compressed under pressure. , which After injection molding and cooling, the external force is removed. For example Even if the seal member is compressed, the sealing member is maintained in a compressed state by the connecting action of the first molding member.

[0009] In one embodiment of the present application, the first molded member is flattened and has a molded ring body and a molded ring inner hole located in the center of the molded ring body, and the molded ring inner hole is used to fit at least a portion of the pole.

[0010] In one embodiment of the present application, the boss cavity is formed in the bottom surface of the molded ring body.

[0011] In one embodiment of the present application, an upper pole, a pole fixing part and a lower pole are formed in this order on the pole, the upper pole and the lower pole are provided to protrude upward and downward from the pole fixing part, respectively, and the pole fixing part is provided to protrude from the upper pole and the lower pole in a lateral direction.

[0012] In one embodiment of the present application, a gap is formed between the pole fixing portion and the connection boss, and the gap is filled with a first molding member during injection molding to provide insulation.

[0013] In one embodiment of the present application, a fourth concave-convex member is provided in the circumferential direction of the pole fixing portion or the upper pole, and a third concave-convex member is correspondingly molded on the first molded member, and the circumferential rotation of the pole is restricted by the concave-convex engagement between the fourth concave-convex member and the third concave-convex member.

[0014] In one embodiment of the present application, the fourth concave-convex member and the third concave-convex member are a notch and a bump, respectively, and a plurality of such members are provided along the circumferential direction.

[0015] In one embodiment of the present application, the molded ring body is provided to enclose the side walls of the upper pole and the pole fixing part, thereby forming a cavity in the molded ring body, and only the upper surface of the pole is exposed after injection molding.

[0016] In one embodiment of the present application, a recessed base is formed in the setting area of ​​the connection boss, and the recessed base is filled with a first molding member after injection molding. A convex base and a concave ring are further provided around the pole post hole, and the concave ring is annular and is recessed into the recessed base, whereby the sealing member is positioned on the convex base and the concave ring.

[0017] In one embodiment of the present application, a second molded member made of an insulating material is further provided below the top cover plate, a first connecting member is provided on the bottom surface of the top cover plate, and a second connecting member is correspondingly provided on the second molded member, and the second molded member is fixedly connected to the bottom of the top cover plate by engagement between the second connecting member and the first connecting member or by connection engagement by thermal fusion.

[0018] In one embodiment of the present application, the top cover plate is further provided with an anti-explosion valve or a liquid inlet.

[0019] In one embodiment of the present application, the explosion-proof valve is a separate type explosion-proof valve, including an explosion-proof valve piece and an explosion-proof valve film, the top cover plate is provided with an explosion-proof valve hole passing therethrough, the explosion-proof valve piece is welded below the explosion-proof valve hole, and the explosion-proof valve film is attached above the explosion-proof valve hole.

[0020] In one embodiment of the present application, the anti-explosion valve is an integrated anti-explosion valve, which includes an anti-explosion valve piece integrally molded on the top cover plate, and an anti-explosion valve film attached to the anti-explosion valve piece.

[0021] In one embodiment of the present application, the positive and negative poles are mounted on the same top cover plate to form an integrated power battery top cover assembly.

[0022] In one embodiment of the present application, the positive and negative poles are mounted on separate top cover plates to form a separate power battery top cover assembly.

[0023] In one embodiment of the present application, the connection boss is formed by pressing the top cover plate, and the connection boss has a columnar structure, a molding hole is provided below it, and a cap-shaped first uneven member is molded on the top.

[0024] In one embodiment of the present application, said connecting bosses are uniformly distributed along a ring concentric with the pole post holes.

[0025] In one embodiment of the present application, pole post mounting hole positions are formed around the pole post hole.

[0026] The present invention Power battery by injection molding Top cover - Structure Construction How to make has the following beneficial effects:

[0027] 1. In the manufacturing process, the process has been simplified, the number of parts is small, and assembly is possible automatically. As a result, the number of workers has been reduced by 50% compared to existing production lines, production volume has increased by 30%, and total costs have been reduced by more than 35%.

[0028] 2. The connection bosses for connecting and fixing the first molded member when injection molding can be obtained by machining them together when molding the top cover plate, without increasing the complexity of the manufacturing process.

[0029] 3. Between the first molded part and the top cover plate, the first uneven part having a cap shape at the top engages with the second uneven part formed in the first molded part during injection molding, thereby pulling the first molded part closer together and avoiding the waste of the finished product due to the laser welding process.

[0030] 4. In some embodiments of the present application, the first molded member encloses all of the connection bosses, and the uneven structure between the first molded member and the terminal post improves the torsional flexibility of the terminal post.

[0031] 5. During the injection molding of the first molding part, a certain pressure is applied to the pole until the first molding part is completely cooled and shaped, so that the sealing of the pole can meet the requirements. [Brief description of the drawings]

[0032] [Figure 1] FIG. 2 is a structural schematic diagram showing the top cover structure of a power battery according to an embodiment of the present invention. [Diagram 2] FIG. 2 is an exploded schematic view showing the structure of the embodiment of FIG. [Diagram 3] FIG. 2 is an exploded schematic cross-sectional view of the embodiment of FIG. 1. [Figure 4] FIG. 2 is a top view showing a top cover plate in the embodiment of FIG. 1. [Diagram 5] FIG. 5 is a bottom view of FIG. [Figure 6] 2 is a schematic diagram showing the structure of a first molded member in the embodiment of FIG. 1 as viewed from below. FIG. [Figure 7] 2 is a schematic diagram showing a cross-sectional structure of a positive electrode post in the embodiment of FIG. 1. [Figure 8] FIG. 2 is a schematic diagram showing the structure of a pole post in the embodiment of FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] In order to allow those skilled in the art to better understand the present invention and more clearly limit the scope of protection claimed by the present invention, the present invention will be described in detail below with reference to some specific examples of the present invention. Note that the following are some specific embodiments based on the structure of the present invention, which are merely a part of the examples of the present invention, and the specific and direct description of the relevant structures therein is merely for the purpose of making the present invention easily understandable, and each specific feature does not substantially and directly limit the scope of the present invention. Any conventional selection and substitution made by those skilled in the art based on the concept of the present invention should be considered to be included in the scope of protection claimed by the present invention.

[0034] A top cover assembly for a power battery, which is manufactured by an injection molding process. - Structure The electrode post assembly 20 includes a structure whereby the electrode post assembly 20 is fixed to the top cover plate 10 to form a positive electrode post 201 or a negative electrode post 202.

[0035] For example, as shown in Fig. 1, the positive pole 201 and the negative pole 202 are formed at intervals on one top cover plate 10, thereby forming an integrated power battery top cover assembly. Of course, in other embodiments, when the positive pole 201 and the negative pole 202 are respectively provided on one top cover plate 10, they can also be formed as a separate power battery top cover assembly.

[0036] In the integrated power battery top cover assembly shown in Fig. 1, an explosion-proof valve 30 and a liquid inlet 14 are further provided between the positive pole 201 and the negative pole 202, where the explosion-proof valve 30 is used to open and release pressure when the pressure inside the battery is too high to ensure the safety of the battery, and the liquid inlet 14 is used to inject electrolyte therein after the battery is assembled. In this embodiment, the explosion-proof valve 30 and the liquid inlet 14 are well known in the art, and are not limited in this application.

[0037] Referring to FIG. 1, below the top cover plate 10, there is further provided a second molding member 40 made of insulating material, the insulating property and material strength of which meet the insulating property and connection requirements of the power battery and are not limited as they are known in the art.

[0038] 2, a pole hole 13 is formed so as to penetrate the top cover plate 10, and pole mounting hole positions 11 for mounting a pole 22 are formed around the pole hole 13. In this embodiment, a seal member 23 is provided between the pole 22 and the top cover plate 10 to insulate and seal them. As shown in the figure, the seal member 23 is a gasket, and the insulating property and compressive elasticity of the material thereof meet the requirements for use.

[0039] 2, the top cover plate 10 is provided with a plurality of connecting bosses 12 on the outer periphery of the pole hole 13. Preferably, the connecting bosses 12 are uniformly distributed along a ring concentric with the pole hole 13. Here, the connecting bosses 12 may be integrally formed with the top cover plate 10 when the top cover plate 10 is formed, or may be obtained by using a corresponding step during the manufacturing process of the top cover plate 10. Preferably, the top cover plate 10 is made of an alloy with excellent formability, such as an aluminum alloy, so that the connecting bosses 12 can be formed by pressing from the bottom up when the top cover plate 10 is formed, and the connecting bosses 12 are further formed with a first uneven member 121 for connecting the first molded member 21 thereto.

[0040] For example, in some embodiments, the connection boss 12 having the first uneven member 121 is manufactured in two steps. In step 1, the top cover plate 10 is first pressed from bottom to top to form a cylindrical convex base, and the lower part of the convex base is hollowed out to form the molding hole 18. In step 2, the molded convex base is pressed from top to bottom to mold the upper part of the base sideways to form the cap-shaped first uneven member 121.

[0041] Of course, the above-mentioned shape of the first concave-convex member 121 is merely an example, and the shape is not limited to this.

[0042] Here, the first molded member 21 is obtained by injection molding onto the top cover plate 10 while maintaining pressure on the electrode post 22, so that the seal member 23 is in a state of being compressed under pressure after the first molded member 21 is cooled and shaped. Moreover, insulation between the electrode post 22 and the top cover plate 10 is ensured by the first molded member 21 or the seal member 23. Here, the degree of compression of the seal member 23 is not limited and may be set as necessary.

[0043] 4, in this embodiment, a recessed base 17 is formed in the region of the top cover plate 10 where the connection boss 12 is set, which is recessed with respect to the other region of the top cover plate 10, and the recessed base 17 is filled with a first molding member 21 after injection molding, so that the pole post assembly 20 and the top cover plate 10 are formed as an integral structure. In addition, a protruding base 15 and a recessed ring 16 provided on the outer periphery of the protruding base 15 are further provided around the pole post hole 13, where the recessed ring 16 is annular and recessed with respect to the recessed base 17.

[0044] 6 and 7, in this embodiment, the first molded member 21 is substantially flat and annular. The first molded member 21 includes a molded ring body 211 and a molded ring inner hole 212 located at the center of the molded ring body 211. The molded ring body 211 is obtained by injection molding on the outer periphery of the pole 22, and the molded ring inner hole 212 is used to fit at least a part of the pole 22.

[0045] A boss cavity 213 for receiving the connecting boss 12, which is also obtained during injection molding, is formed on the bottom surface of the molded ring body 211, and a second uneven member 214 is further provided within the boss cavity 213. The second uneven member 214 fits into the first uneven member 121 of the connecting boss 12 to form a connection relationship by uneven fitting, so that the first molded member 21 is connected to the connecting boss 12 even when fixed to the top cover plate 10.

[0046] As described above, during the injection molding and cooling of the first molded member 21, a certain pressure is applied to the pole 22 to make the seal member 23 compressed under pressure. , which After injection molding and cooling, the external force is removed. For example Even if the terminal posts 22 are compressed, the sealing member 23 is maintained in the above-mentioned compressed state by the action of the first molding member 21. Furthermore, the terminal posts 22 and the top cover plate 10 or the connection bosses 12 are insulated by the first molding member 21 or the sealing member 23, so that the top cover plate 10 is not electrically connected to the terminal posts 22.

[0047] Referring to FIG. 8, the pole 22 is formed as an upper pole 221, a pole fixing part 222 and a lower pole 223 from top to bottom, in which the upper pole 221 and the lower pole 223 are respectively provided to protrude upward and downward from the pole fixing part 222, and the upper pole fixing part 222 is provided to protrude from the upper pole 221 and the lower pole 223 in the lateral direction.

[0048] Therefore, after the pole 22 is installed in the pole hole 13, the lower surface of the pole fixing part 222 comes into contact with the upper surface of the seal member 23, the lower pole 223 is at least partially inserted into the pole hole 13 and insulated by the seal member 23, and a gap is formed between the pole fixing part 222 and the connection boss 12, and this gap is filled and insulated by the first molding member 21 during injection molding.

[0049] In order to enhance the torsional resistance of the pole 22 after injection molding, a fourth uneven member 224 is provided on the pole fixing portion 222 or the upper pole 221, and a third uneven member 215 that can be unevenly engaged with the fourth uneven member 224 during injection molding can be molded into the first molding member 21, thereby restricting the circumferential rotation of the pole 22 and enhancing the torsional resistance of the pole 22.

[0050] In this embodiment, the fourth uneven member 224 is a notch recessed into the side wall of the pole fixing portion 222, and correspondingly, the third uneven member 215 is a bump located on the molded ring main body 211 formed during injection molding. The rotation of the pole 22 is restricted by the engagement of the unevenness between the two, so that in addition to the injection molding adhesion of the first molded member 21 to the pole 22, a rotation restriction structure is also provided.

[0051] In this embodiment, the molded ring body 211 is provided so as to enclose the side walls of the upper pole 221 and the pole fixing portion 222 of the pole 22, thereby forming a cavity 216 in the molded ring body 211, and after injection molding, substantially only the upper surface of the pole 22 is exposed.

[0052] Referring to FIG. 5, a first connecting member 19 for connecting a second molded member 40 is further molded on the bottom surface of the top cover plate 10, and correspondingly, a second connecting member 41 is molded on the second molded member 40, and the first connecting member 19 and the second connecting member 41 have a corresponding concave-convex fitted structure, whereby the second molded member 40 can be connected to be engaged under the top cover plate 10, or the second connecting member 41 is heat-sealed to fit and molded into the first connecting member 19 to form a concave-convex connecting structure.

[0053] 2 and 3, the explosion-proof valve 30 is a separate type explosion-proof valve, in which the top cover plate 10 is provided with an explosion-proof valve hole 31 penetrating therethrough, the explosion-proof valve piece 32 is welded to the explosion-proof valve hole 31 from bottom to top, and the explosion-proof valve film 33 is attached above the explosion-proof valve hole 31. Of course, in other embodiments, a separate type explosion-proof valve may not be provided, and instead, an integrated explosion-proof valve is integrally formed on the top cover plate 10 during the molding process of the top cover plate 10, that is, the explosion-proof valve piece 32 is integrally formed on the top cover plate 10, and the explosion-proof valve film 33 is attached thereon to form the explosion-proof valve 30. [Explanation of symbols]

[0054] A top cover plate 10, a pole assembly 20, an explosion-proof valve 30, a second molded member 40, a positive pole 201, a negative pole 202, A pole mounting hole position 11, a connection boss 12, a pole hole 13, a liquid injection port 14, a protruding base 15, a concave ring 16, a recessed base 17, a forming hole 18, a first connection member 19, A first molded member 21, a pole 22, a seal member 23, Explosion-proof valve hole 31, explosion-proof valve piece 32, explosion-proof valve film 33, second connecting member 41, A first concave-convex member 121, A molded ring body 211, a molded ring inner hole 212, a boss cavity 213, a second uneven member 214, a third uneven member 215, a cavity 216, An upper pole 221 , a pole fixing portion 222 , a lower pole 223 , and a fourth concave-convex member 224 .

Claims

1. A method of manufacturing a top cover plate (10), providing a pole hole (13) in the top cover plate (10) so as to penetrate the top cover plate (10), and providing a plurality of connection bosses (12) on an outer periphery of the pole hole (13) and having a first uneven member (121) formed thereon; a step of preparing a pole assembly (20) including a first molded member (21), a pole (22), and a sealing member (23), and forming a positive pole (201) or a negative pole (202) by fitting the pole assembly (20) to the top cover plate (10), in which the pole (22) is assembled into a pole hole (13), the sealing member (23) is provided between the pole (22) and the top cover plate (10), and the first molded member (21) is formed by injection molding on the outer periphery of the pole (22); Within the first molded member (21), a boss cavity (213) for receiving the connecting boss (12) is molded, within the boss cavity (213), a second uneven member (214) is molded, and the first molded member (21) is connected to the top cover plate (10) by uneven engagement between the first uneven member (121) and the second uneven member (214), whereby the pole (22) and the seal member (23) are fixed to the top cover plate (10) by the first molded member (21); a step of insulating the pole (22) from the top cover plate (10) by the first molding member (21) and the seal member (23); During injection molding and cooling of the first molded member (21), a predetermined pressure is applied to the pole (22) to place the seal member (23) in a compressed state under pressure, so that even if the external force is removed after injection molding and cooling, the seal member (23) is maintained in a compressed state due to the connecting action of the first molded member (21); The first molded member (21) is a flat annular member, and includes a molded ring body (211) and a molded ring inner hole (212) located at the center of the molded ring body (211). The molded ring inner hole (212) is used to fit at least a part of the pole (22). The boss cavity (213) is formed on the bottom surface of the molded ring body (211). The pole (22) is formed with an upper pole (221), a pole fixing part (222) and a lower pole (223) in this order, the upper pole (221) and the lower pole (223) are provided so as to protrude upward and downward from the pole fixing part (222), respectively, the pole fixing part (222) is provided so as to protrude from the upper pole (221) and the lower pole (223) in the lateral direction, a gap is formed between the pole fixing part (222) and the connection boss (12), and the gap is filled and insulated by a first molding member (21) during injection molding, A fourth uneven member (224) is provided in the circumferential direction of the pole fixing portion (222) or the upper pole (221), and a third uneven member (215) is correspondingly molded in the first molded member (21), and the rotation of the pole (22) in the circumferential direction is restricted by the uneven engagement between the fourth uneven member (224) and the third uneven member (215), The fourth uneven member (224) and the third uneven member (215) are a notch and a bump, respectively, and are provided in a plurality along the circumferential direction.

2. The molded ring body (211) is provided to enclose the side walls of the upper pole (221) and the pole fixing part (222), thereby forming a cavity (216) in the molded ring body (211), and only the upper surface of the pole (22) is exposed after injection molding; The method for manufacturing the top cover structure of a power battery by injection molding according to claim 1, characterized in that: a recessed base (17) is formed in the setting area of ​​the connection boss (12), the recessed base (17) is filled with a first molding member (21) after injection molding, a protruding base (15) is further provided around the pole post hole (13) and a concave ring (16) is provided on the outer periphery of the protruding base (15), the concave ring (16) is annular and is provided so as to be recessed into the recessed base (17), thereby the sealing member (23) is positioned on the protruding base (15) and the concave ring (16).

3. The method for manufacturing the top cover structure of the power battery by injection molding according to claim 1, characterized in that: a second molded member (40) made of insulating material is further provided under the top cover plate (10); a first connecting member (19) is provided on the bottom surface of the top cover plate (10); a second connecting member (41) is provided correspondingly on the second molded member (40); and the second connecting member (41) is engaged with the first connecting member (19) or is connected and engaged by heat fusion to fixedly connect the second molded member (40) to the bottom of the top cover plate (10).

4. The top cover plate (10) further includes an explosion-proof valve (30) or a liquid inlet (14); The method for manufacturing the top cover structure of a power battery by injection molding according to claim 1, characterized in that the explosion-proof valve (30) is a separate type explosion-proof valve, comprising an explosion-proof valve piece (32) and an explosion-proof valve film (33), the top cover plate (10) is provided with an explosion-proof valve hole (31) so as to penetrate, the explosion-proof valve piece (32) is welded to the lower part of the explosion-proof valve hole (31), and the explosion-proof valve film (33) is attached to the upper part of the explosion-proof valve hole (31); or the explosion-proof valve (30) is an integrated type explosion-proof valve, comprising an explosion-proof valve piece (32) integrally molded with the top cover plate (10) and an explosion-proof valve film (33) attached to the explosion-proof valve piece (32).

5. The positive electrode pole (201) and the negative electrode pole (202) are mounted on the same top cover plate (10) to form an integrated power battery top cover assembly, or the positive electrode pole (201) and the negative electrode pole (202) are mounted on separate top cover plates (10) to form a separate power battery top cover assembly; The connection boss (12) is formed on the top cover plate (10) by pressing, and the connection boss (12) has a columnar structure, a molding hole (18) is provided below the connection boss (12), and a cap-shaped first uneven member (121) is molded on the upper portion of the connection boss (12). The connecting bosses (12) are uniformly distributed along a ring concentric with the pole post hole (13); 5. The method for manufacturing the top cover structure of the power battery by injection molding as claimed in claim 4, characterized in that: a pole post mounting hole position (11) is formed around the pole post hole (13).

Images