Core rod winding type battery structure convenient to assemble
By setting grooves on the cover plate body and embeding a sealing ring, the welding between the mandrel and the cover plate is cancelled, and the elastic connection method is adopted, the problem of increasing cost and tolerance control difficulty in welding in the prior art is solved, and the effect of simplifying assembly and improving the battery cell pass rate is achieved.
Patent Information
- Application Number
- CN202422302432.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-20
- Publication Date
- 2025-07-22
- Estimated Expiration
- 2034-09-20
AI Technical Summary
The welding of existing lithium battery cell rods and cover plates increases production cost and tolerance control difficulty, affects welding accuracy and quality, resulting in high unqualified battery cell rate.
A groove is provided on the cover plate body and a sealing ring is embedded. The two ends of the mandrel are connected to the cover plate through the sealing ring, and the welding between the mandrel and the cover plate is cancelled, and an elastic connection is adopted.
The assembly process is simplified, production costs are reduced, the cell pass rate and welding quality are improved, and the impact of tolerance on the cell is reduced.
Smart Images
Figure CN223140833U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of batteries, in particular to a mandrel winding type battery structure which is convenient for assembly. Background Art
[0002] Lithium batteries have the characteristics of high output power, high energy density, etc., and are widely used in many fields including electric vehicles, electric bicycles and other electric transportation tools and energy storage facilities. Among them, the mandrel winding type lithium battery is a relatively common lithium battery structure, which includes: a winding core, a positive electrode adapter piece, a negative electrode adapter piece, a positive electrode cover plate assembly, a negative electrode cover plate assembly, a housing and other structures. During assembly: the positive electrode tab on the winding core is welded to the positive electrode cover plate assembly through the positive electrode adapter piece, and the negative electrode tab on the winding core is welded to the negative electrode cover plate assembly through the negative electrode adapter piece. Then, the positive electrode cover plate assembly and the negative electrode cover plate assembly are respectively and hermetically welded to the housing. Further, a mandrel is arranged inside the winding core, and a coolant channel is arranged inside the mandrel. The winding core is formed by winding positive electrode sheets, separators and negative electrode sheets which are stacked on the mandrel. The winding core and the mandrel together constitute the battery cell. As Figure 5 shown: in the prior art, through holes are provided in the centers of the cover plates in the positive and negative electrode cover plate assemblies for corresponding to the hollow structure of the mandrel to lead out the coolant in the mandrel. In order to prevent the battery cell from axially moving in the housing, generally, both ends of the mandrel are laser welded to the cover plate. However, laser welding both ends of the mandrel to the cover plate will, on the one hand, increase two welding processes and improve the production cost of the battery; on the other hand, in order to obtain a higher energy density, the prior art tends to extend the length of the battery cell. In order to match the welding with the cover plate, the dimensional tolerance of the mandrel needs to be controlled within ±0.3 mm. The too long battery cell will increase the difficulty of tolerance control, thus affecting the welding accuracy, welding quality and welding efficiency during welding, resulting in a large number of unqualified battery cells, and further increasing the production cost of the battery invisibly.
[0003] In order to fundamentally solve the above problems, it is urgent to improve the axial fixing method of the battery cell, and for this reason, this application is proposed. Summary of the Utility Model
[0004] In view of the above-mentioned disadvantages of the prior art, the utility model provides a mandrel winding type battery structure which is convenient for assembly.
[0005] In order to achieve the above purpose, the main technical solutions adopted by the utility model include:
[0006] A mandrel winding type battery structure facilitating assembly, comprising an electric core, a positive transfer piece, a negative transfer piece, a positive cover plate assembly, a negative cover plate assembly and a housing. The electric core includes a mandrel and a winding core wound outside the mandrel. The positive tab on the winding core is welded to the positive cover plate assembly through the positive transfer piece, and the negative tab on the winding core is welded to the negative cover plate assembly through the negative transfer piece. The positive cover plate assembly and the negative cover plate assembly are respectively hermetically welded to the front and rear open ends of the housing. The mandrel is of a hollow structure. The positive cover plate assembly and the negative cover plate assembly both contain a cover plate body, and a middle part of the cover plate body is partially recessed to form a groove with a through hole opened at the center. An inner side surface of the groove is structurally matched with outer surface structures at two ends of the mandrel, and a structure of the through hole is matched with the hollow structure. A sealing rubber ring is embedded in the groove. Two ends of the mandrel are arranged in the groove through the sealing rubber ring, and the hollow structure is docked with the through hole.
[0007] Preferably, a filling volume percentage of the sealing rubber ring in the groove is 10%-95%.
[0008] Preferably, the mandrel is a hollow square mandrel, the housing is a prismatic structure with two open ends, the cover plate body is structurally matched with the open end of the housing, and laser welding is performed between the two cover plate bodies and the housing. The groove is a square groove structurally matched with the square mandrel. The square groove includes: side surface I, bottom surface I and square through hole I.
[0009] Preferably, the square groove is 10-200 mm in length, 10-200 mm in width and 5-20 mm in depth, and the square mandrel is 10-2000 mm in length, 10-200 mm in height, 10-200 mm in width and 0.5-10 mm in wall thickness.
[0010] Preferably, a structure of the sealing rubber ring is matched with a structure of the groove. The sealing rubber ring includes side surface II, bottom surface II and square through hole II.
[0011] Preferably, the bottom surface II is 0.3-9 mm in width, the side surface II is 4.5-19 mm in height, and a filling volume percentage of the sealing rubber ring in the groove is 25%-80%.
[0012] More preferably, a filling volume percentage of the sealing rubber ring in the groove is 40%-60%.
[0013] Preferably, the sealing rubber ring is an annular structure with a square inner circumference and a square outer circumference, and the annular structure is structurally matched with the bottom surface I.
[0014] Preferably, the annular structure is 0.3-9 mm in width and 4.5-19 mm in thickness, and a filling volume percentage of the annular structure in the groove is 50%-70%.
[0015] Further preferably, the filling volume percentage of the annular structure in the groove is 55%-65%.
[0016] Compared with the prior art, the easy-to-assemble mandrel winding type battery structure proposed by the present utility model can not only simplify the assembly process, save two welding processes, but also reduce the influence of the tolerance in the length direction of the mandrel on the assembly of the battery core, improve the product qualification rate, help reduce the production cost of the battery, and reduce the assembly difficulty. Description of the Drawings
[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.
[0018] Figure 1 It is a three-dimensional structure diagram of the cover plate body A in the present utility model;
[0019] Figure 2 It is Figure 1 the top view of;
[0020] Figure 3 It is a structural diagram of a sealing rubber ring in the present utility model;
[0021] Figure 4 It is another structural diagram of the sealing rubber ring in the present utility model;
[0022] Figure 5 It is a structural diagram of an existing cover plate.
[0023] In the figure: A, cover plate body; A1, side surface Ⅰ; A2, bottom surface Ⅰ; A3, square through hole Ⅰ; B1, side surface Ⅱ; B2, bottom surface Ⅱ; B3, square through hole Ⅱ; C, annular structure. Detailed Embodiments
[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some, rather than all, embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments in the present application belong to the scope of protection of the present application.
[0025] During the lithium battery assembly process, the axial movement of the battery cell will inevitably bring various adverse effects. For example: short - circuit risk, the axial movement of the battery cell may cause the distance between the positive and negative electrodes inside the battery to change, or even come into direct contact, thus triggering a short - circuit. A short - circuit will instantaneously release a large amount of heat, which may cause the battery to experience thermal runaway and ultimately lead to fire or explosion; performance degradation, the axial movement of the battery cell may also damage the internal structure of the battery, such as the rupture of the separator or the misalignment of the electrodes. These changes will directly affect the performance of the battery, such as capacity attenuation, increased internal resistance, etc.; shortened lifespan, the continuous axial movement of the battery cell will also exacerbate the mechanical stress inside the battery, leading to accelerated aging of the battery materials and thus shortening the cycle life of the battery.
[0026] In the prior art, in order to prevent the axial movement of the battery cell in the housing, generally, both ends of the core rod are laser - welded to the cover plate. However, laser - welding both ends of the core rod to the cover plate will, on the one hand, increase two welding processes, raising the production cost of the battery; on the other hand, in order to obtain a higher energy density, the prior art tends to extend the length of the battery cell. To match the welding with the cover plate, the dimensional tolerance of the core rod needs to be controlled within ±0.3 mm. The longer the battery cell, the greater the difficulty in controlling the tolerance, thus affecting the welding accuracy, welding quality and welding efficiency, resulting in a large number of unqualified battery cells and further increasing the production cost of the battery invisibly.
[0027] The utility model proposes a core - rod winding - type battery structure that is convenient for assembly, including a battery cell, a positive - pole adapter piece, a negative - pole adapter piece, a positive - pole cover - plate assembly, a negative - pole cover - plate assembly, and a housing. The battery cell includes a core rod and a winding core wound around the core rod. The positive - pole tab on the winding core is welded to the positive - pole cover - plate assembly through the positive - pole adapter piece, and the negative - pole tab on the winding core is welded to the negative - pole cover - plate assembly through the negative - pole adapter piece. The positive - pole cover - plate assembly and the negative - pole cover - plate assembly are respectively hermetically welded to the front and rear open ends of the housing. The core rod is a hollow structure. The positive - pole cover - plate assembly and the negative - pole cover - plate assembly both contain a cover - plate body A. A central part of the cover - plate body A is partially recessed to form a groove with a through - hole in the center. The inner side surface of the groove matches the outer surface structure of both ends of the core rod, and the structure of the through - hole matches the hollow structure. A sealing rubber ring is embedded in the groove. Both ends of the core rod are arranged in the groove through the sealing rubber ring, and the hollow structure is docked with the through - hole.
[0028] By setting the above - mentioned groove on the cover - plate body A, on the basis of laser - welding the cover - plate body A to the housing, both ends of the core rod are sealed by compressing the sealing rubber ring, eliminating the need for welding the core rod to the cover - plate body A; moreover, under the elastic action of the sealing rubber ring, the connection between the core rod and the cover - plate body A changes from a previous rigid connection to an elastic connection. This elastic connection can eliminate the adverse effects brought by the core - rod tolerance, improve the qualified rate of the battery cell, and reduce the production cost of the battery.
[0029] It should be noted that: the above-mentioned battery cell, positive electrode adapter piece, negative electrode adapter piece, housing, and other components in the positive electrode cover assembly and negative electrode cover assembly are all prior arts. Those skilled in the art can flexibly select and use them according to actual needs, which are not the improvements of the present utility model, so they will not be elaborated herein.
[0030] Furthermore, in order to ensure the axial fixing stability of the mandrel, the filling volume percentage of the sealing rubber ring in the groove is 10%-95%.
[0031] The filling rate of the sealing rubber ring in the groove directly affects the connection tightness and stability between the mandrel and the groove. An excessively low filling rate will result in insufficient contact area between the two ends of the mandrel and the sealing rubber ring, thus unable to provide sufficient frictional force to ensure the connection stability and tightness; an excessively high filling rate, although increasing the contact area, may make the space in the groove too small, resulting in the mandrel unable to be accommodated, and also unable to ensure the connection smoothness and stability. Through several tests and verifications in this application, when the filling volume percentage of the sealing rubber ring in the groove is 10%-95%, the elastic connection effect between the mandrel and the groove can be basically ensured. On this basis, even if the tolerance in the length direction of the mandrel exceeds ±0.3 mm, the elasticity of the sealing rubber ring can fill the tolerance in the length direction of the mandrel to a certain extent, ensuring the welding accuracy and welding quality. Moreover, workers or machines do not need to adjust the position of the battery cell to ensure the welding accuracy and consistency, without increasing the production cost and time.
[0032] It should be noted that: the present utility model can be used in various mandrel winding battery structures, such as cylindrical mandrel winding battery structures, prismatic mandrel winding battery structures, etc. Only need to set the groove on the cover plate body A to a structure corresponding to the mandrel structure. The shape of the cover plate body A can be flexibly selected according to the shape of the battery. For example, a circular cover plate body is selected for a cylindrical battery, and a square cover plate body is selected for a square battery.
[0033] Designed in this way, compared with the prior art, the present utility model has at least the following beneficial effects:
[0034] 1. Reduce the production process, lower the assembly difficulty, and contribute to improving the production efficiency; 2. Reduce the influence of the tolerance in the length direction of the mandrel on the battery cell, contribute to ensuring the welding accuracy and welding quality, improve the qualified rate of the battery cell without affecting the welding efficiency, and reduce the production cost.
[0035] As a preferred embodiment, another embodiment of the present utility model, the mandrel is a hollow square mandrel, and the housing is a prismatic structure with openings at both ends, such as Figure 1As shown: The cover plate body A is structurally matched with the open end of the housing, and two cover plate bodies A are laser welded to the housing. The groove is a square groove structurally matched with the square mandrel. The square groove includes: side surface ⅠA1, bottom surface ⅠA2, and square through hole ⅠA3.
[0036] The sealing rubber ring is embedded in the square groove. After assembly, the end faces at both ends of the square mandrel are in elastic contact with the bottom surface ⅠA2 through the sealing rubber ring, and its hollow part is opposite to the square through hole ⅠA3. On the basis of laser welding the cover plate body A and the housing, elastic sealing is achieved at both ends of the mandrel by compressing the sealing rubber ring.
[0037] Furthermore, the square groove is 10 - 200 mm in length, 10 - 200 mm in width, and 5 - 20 mm in depth. The square mandrel is 10 - 2000 mm in length, 10 - 200 mm in height, 10 - 200 mm in width, and 0.5 - 10 mm in wall thickness.
[0038] In the above embodiment, the structure of the sealing rubber ring can be any one of the following two structures:
[0039] Structure 1: The structure of the sealing rubber ring is matched with the structure of the groove. The sealing rubber ring includes side surface ⅡB1, bottom surface ⅡB2, and square through hole ⅡB3.
[0040] Furthermore, the bottom surface ⅡB2 is 0.3 - 9 mm in width, the side surface ⅡB1 is 4.5 - 19 mm in height, and the filling volume percentage of the sealing rubber ring in the groove is 25% - 80%, such as 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, etc.; preferably, the filling volume percentage of the sealing rubber ring in the groove is 40% - 60%, such as 42%, 44%, 46%, 48%, 52%, 54%, 56%, 58%, etc.
[0041] The sealing rubber ring is embedded in the groove. The side surface ⅡB1 is closely attached to the side surface ⅠA1, the bottom surface ⅡB2 is closely attached to the bottom surface ⅠA2, the square ⅡB3 is opposite to the square through hole ⅠA3. The end faces at both ends of the mandrel are tightly attached to the bottom surface ⅠA2 through the bottom surface ⅡB2. The hollow structure inside the mandrel is exposed through the square ⅡB3 and the square through hole ⅠA3 for the introduction and discharge of the coolant. During assembly, the cover plate body A and the housing are laser welded, and elastic sealing and axial and radial reinforcement are achieved at both ends of the mandrel by compressing the sealing rubber ring. It is not necessary to weld the mandrel to the cover plate body A to achieve an effect close to welding.
[0042] Structure 2: The sealing rubber ring is an annular structure C with a square inner circumference and an outer circumference, and the annular structure C is structurally matched with the bottom surface ⅠA2.
[0043] Furthermore, the annular structure C has a width of 0.3 - 9 mm and a thickness of 4.5 - 19 mm, and the filling volume percentage of the annular structure C in the groove is 50% - 70%, preferably 55% - 65%.
[0044] The annular structure C is embedded in the groove. The annular structure C is in close contact with the bottom surface ⅠA2. The two end faces of the mandrel are in close contact with the bottom surface ⅠA2 through the annular structure C. The hollow structure provided in the mandrel is naturally exposed for the introduction and discharge of the coolant. During assembly, the cover body A and the housing are laser welded. The two ends of the mandrel are sealed and axially reinforced by compressing the annular structure C. The mandrel and the cover body A can achieve an effect close to welding without welding.
[0045] It should be noted that in the above embodiments, regardless of the structure of the sealing rubber ring, its material is selected as a rubber material that is corrosion-resistant and has flexibility and elasticity, such as fluororubber, ethylene propylene diene monomer rubber and other existing or potentially existing rubber materials that are corrosion-resistant and have certain flexibility and elasticity, or other materials close to rubber.
[0046] In summary, the present utility model seals the two ends of the mandrel by compressing the sealing rubber ring on the basis of laser welding the cover body A and the housing by providing a groove and a sealing rubber ring on the cover body A, without welding the mandrel and the cover body A; moreover, it can effectively eliminate the adverse effects brought by the mandrel tolerance, improve the qualification rate of the battery cells, and reduce the production cost of the battery.
[0047] Although the embodiments of the present utility model have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present utility model. Those of ordinary skill in the art can make changes, modifications, substitutions and deformations to the above embodiments within the scope of the present utility model. In addition, without conflict, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.
Claims
1. A mandrel winding type battery structure convenient for assembly, comprising a battery cell, a positive transfer sheet, a negative transfer sheet, a positive cover plate assembly, a negative cover plate assembly, and a housing. The battery cell includes a mandrel and a winding core wound around the mandrel. The positive tab on the winding core is welded to the positive cover plate assembly through the positive transfer sheet, and the negative tab on the winding core is welded to the negative cover plate assembly through the negative transfer sheet. The positive cover plate assembly and the negative cover plate assembly are respectively and hermetically welded to the front and rear open ends of the housing. The mandrel is of a hollow structure, and is characterized in that: Both the positive electrode cover plate assembly and the negative electrode cover plate assembly include a cover plate body (A). A central part of the cover plate body (A) is partially recessed to form a groove with a through hole in the center. The inner side surface of the groove is structurally matched with the outer surface of both ends of the core rod. The structure of the through hole is matched with the hollow structure. A sealing rubber ring is embedded in the groove. Both ends of the core rod are arranged in the groove through the sealing rubber ring, and the hollow structure is docked with the through hole.
2. The core rod winding type battery structure convenient for assembly according to claim 1, wherein: The filling volume percentage of the sealing rubber ring in the groove is 10%-95%.
3. The core rod winding type battery structure convenient for assembly according to claim 1, characterized in that: The core rod is a hollow square core rod, and the housing is a prismatic structure with openings at both ends. The cover plate body (A) is structurally matched with the open end of the housing, and the two cover plate bodies (A) and the housing are laser welded. The groove is a square groove structurally matched with the square core rod. The square groove includes: side surface I (A1), bottom surface I (A2), and square through hole I (A3).
4. The core rod winding type battery structure convenient for assembly according to claim 3, wherein: The square groove has a length of 10-200 mm, a width of 10-200 mm, and a depth of 5-20 mm. The square core rod has a length of 10-2000 mm, a height of 10-200 mm, a width of 10-200 mm, and a wall thickness of 0.5-10 mm.
5. The core rod winding type battery structure convenient for assembly according to claim 3, characterized in that: The structure of the sealing rubber ring is matched with the structure of the groove. The sealing rubber ring includes side surface II (B1), bottom surface II (B2), and square through hole II (B3).
6. The core rod winding type battery structure convenient for assembly according to claim 5, wherein: The width of the bottom surface II (B2) is 0.3-9 mm, the height of the side surface II (B1) is 4.5-19 mm, and the filling volume percentage of the sealing rubber ring in the groove is 25%-80%.
7. The core rod winding type battery structure convenient for assembly according to claim 6, wherein: The filling volume percentage of the sealing rubber ring in the groove is 40%-60%.
8. The core rod winding type battery structure convenient for assembly according to claim 3, wherein: The sealing rubber ring is an annular structure (C) with a square inner circumference and an outer circumference, and the annular structure (C) is structurally matched with the bottom surface I (A2).
9. The core rod winding type battery structure convenient for assembly according to claim 8, wherein: The annular structure (C) has a width of 0.3-9 mm and a thickness of 4.5-19 mm, and the filling volume percentage of the annular structure (C) in the groove is 50%-70%.
10. The core rod winding type battery structure convenient for assembly according to claim 9, wherein: The filling volume percentage of the annular structure (C) in the groove is 55%-65%.