Extremely simple cover plate assembly and lithium battery

Abstract

The extremely simple cover plate assembly comprises a cover plate body provided with an electrode lead-out hole, a limiting step extends above or below the cover plate body along the circumferential direction of the electrode lead-out hole, and positioning grooves are formed in two ends of the electrode lead-out hole; the pole is arranged in the electrode lead-out hole in a penetrating manner, and the peripheral surface of the pole is a rough plane; the plastic part is located between the cover plate body and the pole and wraps the limiting step, and female buckles are arranged at the two ends below the plastic part; an electrode via hole is formed in the lower plastic support, a first elastic arm and a second elastic arm are arranged in the circumferential direction of the electrode via hole, and male buckles corresponding to the female buckles are arranged at the ends of the first elastic arm and the second elastic arm. The lithium battery further comprises a pole group and a shell. According to the utility model, the number of structural members in the cover plate assembly is greatly reduced, the structures and assembly difficulty of the cover plate assembly and the lithium battery are simplified, and the assembly yield of the cover plate assembly and the lithium battery is improved at the same time.

Description

Technical Field

[0001] The utility model relates to the technical field of secondary batteries, in particular to a cover plate assembly and a lithium battery with a extremely simple structure. Background Art

[0002] With the increasing maturity of lithium-ion battery technology, lithium-ion batteries are widely used as power batteries in electric vehicles and energy storage fields, and the requirements for the use performance and safety of lithium-ion batteries are increasing day by day. As a component in a lithium-ion battery, the function of the lithium battery cover plate is firstly to isolate the internal and external environments after welding with the aluminum shell to play a sealing role; secondly, it is to connect the internal and external circuits and convey the current inside the battery to the outside through the cover plate pole column to play a current guiding role.

[0003] Traditional cover plates generally mainly consist of a light aluminum sheet, (positive and negative) pole columns, (positive and negative) upper plastics, a lower insulating part, etc. During assembly, an upper plastic part, a light aluminum sheet, a lower plastic part and a sealing ring are clamped between the pole column bottom plate and the voltage conducting block. After clamping, the upper end of the pole column and the voltage conducting block are fixed by riveting and laser welding.

[0004] However, the number of structural parts of such a cover plate is relatively large. On the one hand, it leads to numerous assembly processes of the cover plate, relatively complex equipment and tooling, and a slow production beat; on the other hand, the unqualified rate of the cover plate remains high and the cost is difficult to reduce. Content of the Utility Model

[0005] Therefore, the technical problem to be solved by the utility model is to overcome the defect of the complex structure of the cover plate in the prior art, provide a cover plate assembly with an extremely simple structure, and thereby improve the assembly yield rate of the cover plate assembly.

[0006] To solve the above technical problem, the utility model provides an extremely simple cover plate assembly, including:

[0007] A cover plate body, on which an electrode lead-out hole is provided, a limiting step extends above or below the cover plate body along the circumference of the electrode lead-out hole, and positioning grooves are provided at both ends of the electrode lead-out hole;

[0008] A pole column, which is inserted into the electrode lead-out hole, and the outer peripheral surface of the pole column is a rough plane;

[0009] A plastic part, which is located between the cover plate body and the pole column and wraps the limiting step, and female buckles are provided at both ends below the plastic part;

[0010] A lower plastic bracket, on which an electrode through-hole is provided, a first elastic arm and a second elastic arm are provided circumferentially around the electrode through-hole, and the ends of the first elastic arm and the second elastic arm are male buckles corresponding to the female buckles.

[0011] In an embodiment of the present utility model, a positioning groove is provided on the cover plate body corresponding to the other side of the limiting step.

[0012] In an embodiment of the present utility model, the female buckle is provided at both ends of the plastic part corresponding to the length direction of the cover plate body.

[0013] In an embodiment of the present utility model, an elastic arm groove is formed on the top surface of the lower plastic bracket, and a first elastic arm is formed between the two elastic arm grooves.

[0014] In an embodiment of the present utility model, a first support part extends from the lower plastic bracket into the lithium battery, and the side wall of the first support part serves as the second elastic arm.

[0015] In an embodiment of the present utility model, connecting arms extend downward from both sides of the lower plastic bracket corresponding to the electrode through holes. The width dimension of the upper part of the connecting arm matches the position of the plastic part. The width of the lower part of the connecting arm is greater than that of the upper part, and the width of the lower part of the connecting arm is 0.5 - 2 mm.

[0016] In an embodiment of the present utility model, a window is formed in the connecting arm corresponding to the position of the positive electrode post.

[0017] In an embodiment of the present utility model, the plastic part is formed by injection molding between the cover plate body and the post.

[0018] In an embodiment of the present utility model, the plastic part outside the positive electrode post is conductive plastic.

[0019] A lithium battery includes the above-mentioned minimalist cover plate assembly, and is characterized in that it further includes a housing and a pole group. The pole group is placed in the housing. The lower end of the post is welded and fixed to the pole ear of the pole group, and the cover plate body is hermetically welded to the housing.

[0020] The above technical solution of the present utility model has the following advantages compared with the prior art:

[0021] In the minimalist cover plate assembly and the lithium battery of the present utility model, by reducing the number of structural parts in the cover plate assembly, the structure and assembly difficulty of the cover plate assembly are simplified. At the same time, the stability of the structure of the cover plate assembly can be ensured, thereby improving the assembly yield of the cover plate assembly and the lithium battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to make the content of the present utility model easier to be clearly understood, the following further describes the present utility model in detail according to the specific embodiments of the present utility model in conjunction with the drawings, where:

[0023] Figure 1It is the top view of the cover plate assembly of the present utility model;

[0024] Figure 2 It is the exploded view of the first embodiment of the cover plate assembly of the present utility model;

[0025] Figure 3 It is Figure 1 the sectional view taken along the A-A direction in

[0026] Figure 4 It is the rear view of the cover plate body in the present utility model;

[0027] Figure 5 It is the schematic diagram of the pole column in the present utility model;

[0028] Figure 6 It is the SEM image of the surface of the pole column in the present utility model;

[0029] Figure 7 It is the schematic diagram of the plastic part in the present utility model;

[0030] Figure 8 It is the schematic diagram of the lower plastic bracket in the present utility model;

[0031] Figure 9 It is the schematic diagram of the first embodiment of the elastic arm;

[0032] Figure 10 It is the schematic diagram of the second embodiment of the elastic arm;

[0033] Figure 11 It is Figure 1 the sectional view taken along the B-B direction in

[0034] Figure 12 It is the side view of the cover plate assembly of the present utility model;

[0035] Figure 13 It is the exploded view of the lithium battery structure of the present utility model.

[0036] Explanation of the reference numerals in the drawings of the specification:

[0037] 100, cover plate assembly;

[0038] 10, cover plate body; 11, electrode lead-out hole; 12, first positioning step; 13, limiting step; 14, positioning groove; 15, positioning slot; 16, safety valve hole; 161, safety valve piece; 162, protection patch; 163, first installation groove; 164, second installation groove; 165, strengthening rod; 17, liquid injection hole; 171, third installation groove; 172, sealing aluminum nail;

[0039] 20, pole column;

[0040] 30, plastic part; 31, female buckle;

[0041] 40. Lower plastic bracket; 41. Electrode via hole; 42. First elastic arm; 43. Second elastic arm; 44. Male buckle; 45. Elastic arm groove; 46. First support portion; 47. Connecting arm; 48. Window

[0042] 200. Housing

[0043] 300. Electrode group; 310. Tab Detailed implementation mode

[0044] The present utility model will be further described below in conjunction with the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the present utility model and be able to implement it, but the specific embodiments cited shall not be used as a limitation to the present utility model.

[0045] Refer to Figure 1 , Figure 2 and Figure 3 As shown, it is a schematic diagram of an embodiment of the minimalist cover assembly 100 of the present utility model. In the cover assembly 100 of the present utility model, it includes a cover body 10, a pole column 20, a plastic part 30 and a lower plastic bracket 40. Among them, an electrode lead-out hole 11 is provided on the cover body 10, the pole column 20 is inserted into the electrode lead-out hole 11, the plastic part 30 is formed between the cover body 10 and the pole column 20, surrounds the outer periphery of the pole column 20, and fixes the pole column 20 on the cover body 10. An electrode via hole 41 is provided on the lower plastic bracket 40, the pole column 20 surrounded by the plastic part 30 passes through the electrode via hole 41, and the female buckle 31 on the plastic part 30 cooperates with the male buckle 44 on the lower plastic bracket 40 to be fastened, fixing the lower plastic bracket 40 and the cover body 10, and completing the assembly of the cover assembly 100. Compared with the traditional cover assembly 100, not only the setting of the voltage-conducting sheet and the sealing ring is cancelled, but also the upper plastic part 30 and the lower plastic part 30 form an integral structure, greatly reducing the number of structural parts in the cover assembly 100, simplifying the structure and assembly difficulty of the cover assembly 100, and at the same time improving the assembly yield of the cover assembly 100.

[0046] Next, the structure of the cover assembly 100 will be introduced in detail in conjunction with the accompanying drawings of the specification.

[0047] Refer to Figure 2 and Figure 4 As shown in the figure, in this embodiment, the cover body 10 is a rectangular plate, and a first positioning step 12 corresponding to the inner peripheral dimension of the housing 200 is provided on the lower surface of the cover body 10, so as to snap-position the cover assembly 100 on the housing 200. The position of the cover assembly 100 is restricted by the first positioning step 12, avoiding the movement of the cover assembly 100, increasing the stability during welding, facilitating the welding and fixing of the cover assembly 100, and the weld seam is located on the side of the lithium battery, improving the sealing performance of the housing 200.

[0048] The cover plate body 10 is provided with electrode lead holes 11, so that the pole columns 20 can pass through the cover plate body 10 to lead out the current generated inside the lithium battery. Specifically, two electrode lead holes 11 are symmetrically arranged at both ends of the cover plate body 10, corresponding to the positive pole column 20 and the negative pole column 20 respectively, so that the positive and negative poles of the lithium battery are led out from the same end, reducing the occupation of the internal space of the lithium battery by the cover plate assembly 100, increasing the effective space utilization rate of the electrode group 300, reducing the manufacturing difficulty, and improving the production efficiency. At the same time, by optimizing the distribution of the tabs 310, the internal resistance of the battery core is further reduced, and the battery performance is improved.

[0049] The shape of the electrode lead hole 11 is set according to the shape of the pole column 20. In this embodiment, the pole column 20 adopts an elliptical cylindrical structure, so the electrode lead hole 11 is an elliptical hole. The fixation of the pole column 20 and the cover plate body 10 is achieved by injecting a plastic part 30 between the pole column 20 and the cover plate body 10. In order to ensure the stability of the connection between the plastic part 30 and the cover plate body 10, a limiting step 13 extends upward or downward from the cover plate body 10 along the circumference of the electrode lead hole 11. In this embodiment, the limiting step 13 extends downward from the cover plate body 10. After injection molding, the plastic part 30 wraps the limiting step 13, making the connection between the injection molded part and the cover plate body 10 more stable. In order to form the limiting step 13, in the present invention, the cover plate body 10 is extruded along the circumference of the electrode lead hole 11 to form a positioning groove 14 corresponding to the limiting protrusion on the upper surface of the cover plate body 10, which further strengthens the connection stability between the plastic part 30 and the cover plate body 10. At the same time, in order to facilitate the positioning of the pole column 20 and the cover plate body 10 during injection molding and prevent glue overflow and running during injection molding, a positioning groove 15 is provided along the circumference of the electrode lead hole 11. The thickness of the square lithium battery in the present invention is relatively small, and the width of the cover plate body 10 is 1.5 - 3 times the width of the pole column 20. If the positioning groove 15 is arranged on both sides of the cover plate body 10 corresponding to the width of the electrode lead hole 11, it is easy to cause the strength of both sides of the cover plate body 10 to be too small. Therefore, in the present invention, the positioning groove 15 is arranged at both ends of the long axis of the electrode lead hole 11.

[0050] Refer to Figure 5 As shown, the pole column 20 in the present invention is an elliptical cylindrical structure, and the outer peripheral surface of the pole column 20 is a plane, which is convenient for the processing of the pole column 20 and reduces the cost of the pole column 20. In order to ensure that the pole column 20 can be tightly combined with the injection molded part, in the present invention, the outer peripheral surface of the pole column 20 is made into a rough surface by means of grinding, polishing or etching, refer to Figure 6 as shown in the electron microscope image in

[0051] Refer to Figure 7As shown, the plastic part 30 in the present utility model is injection-molded. One side of the plastic part 30 fits against the pole 20 and is interlocked with the rough surface of the pole 20, increasing the bonding force between the two, so that the pole 20 can ensure stable connection even without setting grooves or other limiting structures. In the present utility model, in order to facilitate the connection with the lower plastic bracket 40, a female buckle 31 is provided below the plastic part 30. Since the thickness of the lithium battery in the present utility model is relatively small, if the female buckle 31 is arranged at both ends of the short axis direction of the plastic part 30, it is not convenient to set the male buckle 44 on the lower plastic bracket 40 and affects the strength of the lower plastic bracket 40. Therefore, the female buckle 31 is arranged at both ends of the long axis direction of the plastic part 30, that is, at both ends corresponding to the length direction of the cover plate body 10. This position also corresponds to the position of the positioning groove 15, and the thickness of the plastic part 30 here is greater, so the strength of the female buckle 31 can also be ensured.

[0052] Furthermore, in order to reduce the corrosion risk of the lithium battery, one of the two plastic parts 30 is made of conductive plastic. By setting conductive plastic between the pole 20 and the cover plate body 10, the cover plate body 10 and the pole 20 can be weakly conductively connected through the conductive plastic, so as to ensure the equipotential connection between the cover plate body 10 and the housing 200 and prevent the housing 200 from being corroded due to potential reaction. This design not only improves the safety of the battery but also effectively prevents the corrosion of the cover plate body 10. The weak conductivity of the conductive plastic means that the current on the cover plate body 10 and the housing 200 is small and will not cause short circuit between the positive and negative electrodes, thus reducing the risk of battery short circuit and increasing the safety of battery use. In addition, the application of conductive plastic also takes into account the chemical resistance of the lithium battery, especially the corrosion resistance to the electrolyte, ensuring the stability and safety of the lithium battery during long-term use.

[0053] Refer to Figure 8 As shown, in order to enable the pole 20 to connect to the pole ear 310, an electrode through-hole 41 is provided on the lower plastic bracket 40, and the pole 20 passes through the electrode through-hole 41 and is welded and fixed to the pole ear 310. First elastic arms 42 and second elastic arms 43 are arranged circumferentially around the electrode through-hole 41 on the lower plastic bracket 40, and the ends of the first elastic arms 42 and the second elastic arms 43 are male buckles 44 corresponding to the female buckle 31. Part of the male buckle 44 is snapped into part of the female buckle 31, and the tight connection between the male buckle 44 and the female buckle 31 is realized through the elastic deformation of the two elastic arms. In order to ensure the cooperation between the male buckle 44 and the female buckle 31, in the present utility model, guiding chamfer angles are provided on the sides of the male buckle 44 and the female buckle 31 opposite to each other at the ends. The self-locking reverse buckle is adopted in the present utility model, which has strong flexibility and is convenient for installation.

[0054] Refer to Figure 9As shown in FIG. 1 , a schematic diagram of an embodiment of an elastic arm is shown. As shown in the figure, an elastic arm groove 45 is formed on the top surface of the lower plastic support 40 along the electrode via 41 outwardly, and the lower plastic support 40 between the two elastic arm grooves 45 forms the first elastic arm 42. Figure 10 FIG. 4 is a schematic diagram of another embodiment of the elastic arm. A first support portion 46 extends from the lower plastic bracket 40 toward the inside of the lithium battery, and the side wall of the first support portion 46 serves as the second elastic arm 43. During the buckling process between the male buckle 44 and the female buckle 31, the first elastic arm 42 and the second elastic arm 43 are elastically deformed, and the male buckle 44 is partially inserted into the female buckle 31.

[0055] Furthermore, due to the presence of the electrode via hole 41, the width of the lower plastic support 40 corresponding to the positions on both sides of the short axis of the electrode via hole 41 is relatively narrow, and thus the strength is relatively low. Figure 11 As shown, in order to improve the strength of this part, the lower plastic support 40 has connecting arms 47 extending downward on both sides corresponding to the electrode vias 41, and the width of the upper part of the connecting arm 47 matches the position of the plastic part 30, and the width of the lower part of the connecting arm 47 is equal to or greater than the upper part. The width of the lower part of the connecting arm 47 is preferably greater than the upper part, and at this time, the lower part of the connecting arm 47 partially blocks the plastic part 30. In this setting, since the side of the pole 20 is completely blocked by the connecting arm 47, the short circuit caused by the short-circuit of the pole ear 310 to the shell 200 is avoided. Specifically, the width of the lower part of the connecting arm 47 in this embodiment is set to 0.5-2mm. By widening the size of the lower part of the connecting arm 47, the interference between the connecting arm 47 and the plastic part 30 is avoided, and the strength of the lower plastic support 40 is strengthened, thereby improving the yield of the cover assembly 100.

[0056] Reference Figure 12 As shown, in order to further avoid the position of the plastic part 30, the connecting arm 47 is provided with a window 48 at a position corresponding to the pole 20. The length of the window 48 is smaller than the length of the long axis of the plastic part 30, and further smaller than the length of the long axis of the pole 20, so as to avoid the pole ear 310 extending from the window 48 and short-circuiting with the housing 200.

[0057] Reference Figure 2 and Figure 4As shown in the figure, an oval safety valve hole 16 is further provided at the middle position of the cover plate body 10. The safety valve hole 16 is sealed by a safety valve piece 161, and a protective patch 162 is arranged outside the safety valve piece 161. In order to facilitate the installation of the safety valve piece 161 and the protective patch 162, and at the same time ensure the strength of the cover plate body 10 at the safety valve hole 16, the cover plate body 10 around the safety valve hole 16 is integrally stamped downward so that the height of the lower surface of the cover plate body 10 around the safety valve hole 16 is lower than the height of its main part. At the same time, a first installation groove 163 is formed on the upper surface of the cover plate body 10, and the safety valve piece 161 is welded and fixed in the first installation groove 163. Similarly, the cover plate body 10 around the first installation groove 163 is stamped downward to form a second installation groove 164 on the upper surface of the cover plate body 10, and the protective patch 162 is welded and fixed in the second installation groove 164.

[0058] Furthermore, after the safety valve hole 16 is provided, the width of the cover plate body 10 on both sides of the safety valve hole 16 is smaller. Since the cover plate body 10 needs to be welded and fixed to the housing 200, and the welding position has tensile stress on the cover plate body 10 on both sides of the safety valve hole 16, and at the same time, the battery cells will be subject to external extrusion force during use, both of which will affect the stability of the safety valve piece 161. Therefore, a reinforcing rod 165 integrally formed with the cover plate body 10 is provided in the safety valve hole 16. Refer to Figure 4 As shown in the figure, in one embodiment, the reinforcing rod 165 is parallel to the short axis direction of the safety valve hole 16, that is, the short side direction of the cover plate assembly 100, and at least one is provided. In another embodiment, the reinforcing rod 165 can also be a structure in a continuous V shape with both ends connected to the two sides corresponding to the short axis of the safety valve hole 16. The reinforcing rod 165 supports the safety valve hole 16, can offset the tensile stress and the extrusion force, and prevent the cover plate body 10 and the safety valve piece 161 from deforming or cracking under the action of the tensile stress, the extrusion force, etc.

[0059] A liquid injection hole 17 is also provided in the middle of the cover plate body 10. The size of the liquid injection hole 17 is smaller than the size of the safety valve hole 16. Similar to the safety valve hole 16, the cover plate body 10 around the liquid injection hole 17 is stamped so that the height of the lower surface of the liquid injection hole 17 is lower than the height of the main part of the cover plate body 10, thereby forming a third installation groove 171 on the upper surface of the cover plate body 10, and the sealing aluminum nail 172 is fixed in the third installation groove 171. The setting of the installation groove makes the surface of the cover plate assembly 100 relatively flat except for the pole column 20 area, which is convenient for assembly.

[0060] Refer to Figure 13As shown in the figure, a lithium battery is disclosed. Specifically, it includes the above-mentioned cover assembly 100, and also includes a housing 200 and a pole group 300. Since the positive and negative electrode posts 20 are both provided on the cover assembly 100, in this embodiment, the housing 200 is an integrally formed square hollow column with only one end open. During assembly, the pole group 300 is placed inside the housing 200, and the end of the pole group 300 provided with pole tabs 310 faces the opening. After the cover assembly 100 is assembled, the cover assembly 100 is aligned with the open end of the housing 200, and the lower end of the electrode post 20 is welded and fixed to the pole tab 310 of the pole group 300. Specifically, the electrode post 20 and the pole tab 310 are fixed by a combination of ultrasonic and laser welding. Then, the cover body 10 and the housing 200 are hermetically welded to seal the square battery cell. Since the cover assembly 100 has fewer structural parts, the assembly difficulty of the cover assembly 100 and the lithium battery is simplified, and at the same time, the assembly yield of the cover assembly 100 and the lithium battery is improved.

[0061] Obviously, the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A minimalist cover assembly, characterized in that: include: A cover plate body, wherein the cover plate body is provided with an electrode lead-out hole, a limited step is extended above or below the cover plate body along the circumference of the electrode lead-out hole, and positioning grooves are provided at both ends of the electrode lead-out hole; A pole, the pole is inserted into the electrode lead-out hole, and the outer peripheral surface of the pole is a rough plane; A plastic part, the plastic part is located between the cover plate body and the pole and wraps the limiting step, and female buckles are arranged at both ends of the lower side of the plastic part; A lower plastic bracket is provided with an electrode via hole, and a first elastic arm and a second elastic arm are circumferentially provided with the electrode via hole, and ends of the first elastic arm and the second elastic arm are male buckles corresponding to the female buckle.

2. A minimalist cover assembly according to claim 1, characterized in that: A positioning groove is arranged on the other side of the cover body corresponding to the limiting step.

3. The minimalist cover assembly according to claim 1, characterized in that: The female buckles are arranged at two ends of the plastic component corresponding to the length direction of the cover body.

4. A minimalist cover assembly according to claim 3, characterized in that: An elastic arm groove is formed on the top surface of the lower plastic bracket, and a first elastic arm is formed between the two elastic arm grooves.

5. The minimalist cover assembly according to claim 3, characterized in that: A first supporting portion extends from the lower plastic support toward the interior of the lithium battery, and a side wall of the first supporting portion serves as the second elastic arm.

6. The minimalist cover assembly according to claim 1, characterized in that: The lower plastic bracket has connecting arms extending downwardly on both sides corresponding to the electrode vias, the width of the upper portion of the connecting arm matches the position of the plastic part, the width of the lower portion of the connecting arm is equal to or greater than the width of the upper portion, and the width of the lower portion of the connecting arm is 0.5-2mm.

7. The minimalist cover assembly according to claim 6, characterized in that: The connecting arm is provided with a window at a position corresponding to the pole of the positive electrode.

8. The minimalist cover assembly according to claim 1, characterized in that: The plastic part is formed between the cover plate body and the pole by injection molding.

9. The minimalist cover assembly according to claim 1, characterized in that: The plastic part outside the positive electrode column is conductive plastic.

10. A lithium battery, comprising the minimalist cover assembly according to any one of claims 1 to 9, characterized in that: It also includes a shell and a pole group, the pole group is placed in the shell, the lower end of the pole is welded and fixed to the pole ear of the pole group, and the cover plate body is sealed and welded to the shell.

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