A negative electrode cover plate and a cylindrical battery

Abstract

The application discloses a negative cover plate and a cylindrical battery, which are arranged at one end of a negative electrode of a single-through battery shell and comprise a circular negative current collector, a riveting pole, a negative electrode base plate and a lower plastic plate; the negative current collector is connected with a battery roll core arranged in the single-through battery shell; a protruding structure is arranged at the center of one side of the negative current collector; the riveting pole is arranged at one side of the negative current collector; the lower plastic plate is arranged at the side of the negative current collector away from the battery roll core; the negative electrode base plate is arranged at the side of the lower plastic plate away from the negative current collector; the negative electrode base plate and the lower plastic plate are arranged on the outer side of the riveting pole; beneficial effects are as follows: traditional welding processes such as laser welding, ultrasonic welding and resistance welding are completely cancelled, and defects such as welding slag, virtual welding and welding penetration are eliminated from the source, and cumbersome steps such as slag cleaning and multiple bending positioning are saved.

Description

Technical Field

[0001] This invention relates to the field of new energy batteries, and in particular to a negative electrode cover plate and a cylindrical battery. Background Technology

[0002] Cylindrical batteries, especially high-capacity (such as the 32, 46, and 60 series) cylindrical batteries with a full-tab structure, are widely used in electric vehicles, energy storage systems, and other fields due to their high power, low internal resistance, and excellent thermal management performance. Traditional full-tab cylindrical batteries typically use welding processes to achieve their internal electrical connections.

[0003] Specifically, existing cover plate assemblies mainly consist of structural components such as pole posts, top cover plates, sealing rings, manifolds, lower plastic parts, and upper plastic parts. During assembly, the full-length tabs of the core need to be connected to the manifold first, and then the manifold is connected to the pole posts. Currently, the common technical solutions for achieving these connections are traditional welding methods such as laser welding, ultrasonic welding, or resistance welding.

[0004] However, existing manufacturing technologies for cylindrical batteries with all tabs that rely on welding have technical drawbacks. The welding process generates a large amount of welding slag, which is difficult to clean and prone to residue, increasing the risk of internal short circuits in the battery. Furthermore, the welding process itself requires extremely high precision, making it susceptible to defects such as incomplete welds, burn-through, and explosions, leading to a decrease in product yield. In addition, the multiple welding steps and subsequent cleaning processes make the assembly process complex, time-consuming, and limit production efficiency.

[0005] The positive and negative terminals often adopt symmetrical complex structures, and the busbars are mostly long strips or multi-branched shapes. Assembly requires multiple bending and positioning, making the process lengthy. The bending structure and welding safety distance occupy a large amount of the axial height of the shell, compressing the effective space of the core and restricting the improvement of energy density.

[0006] The current is conducted through multiple stages via the busbar and terminals, resulting in a long path and many connection interfaces. The contact resistance and ohmic internal resistance are superimposed, leading to a high DC internal resistance (DCIR) of the battery cell, which limits the rate performance, cycle life and fast charging capability. Summary of the Invention

[0007] Purpose of the invention: The purpose of this invention is to solve the technical problems in the prior art and provide a negative electrode cover plate and a cylindrical battery.

[0008] Technical solution: This application proposes a negative electrode cover plate, which is disposed at one end of the negative electrode of a single-pass battery casing, including: a circular negative electrode current collector, a riveted electrode post, a negative electrode substrate and a lower plastic plate.

[0009] The negative electrode current collector is connected to the battery core disposed inside the single-pass battery casing;

[0010] The negative electrode current collector has a protruding structure at the center of one side, and a riveted pole is provided on one side of the negative electrode current collector.

[0011] The lower plastic plate is located on the side of the negative electrode current collector away from the battery core, and the negative electrode substrate is located on the side of the lower plastic plate away from the negative electrode current collector.

[0012] The negative electrode substrate and the lower plastic plate are sleeved on the outside of the riveted electrode post;

[0013] The protruding structure is embedded in the groove at one end of the riveted pole and welded and fixed.

[0014] Preferably, the negative electrode current collector is electrically connected to the battery core disposed in the single-pass battery casing via conductive adhesive;

[0015] The conductive adhesive coating thickness is 0.05mm to 0.5mm.

[0016] Preferably, the protruding structure is a threaded elastic buffer metal structure.

[0017] Preferably, the protruding structure has a height of 0.2mm to 1.5mm and an axial extension range of 0.2mm to 1.5mm.

[0018] Preferably, the side of the negative electrode current collector that is connected to the conductive adhesive is a roughened surface;

[0019] The surface roughness is Ra1um~10um.

[0020] Preferably, the lower plastic plate has multiple supporting ribs distributed along the circumferential direction on the side near the negative electrode current collector, and the number of supporting ribs is 4 to 16.

[0021] Preferably, the lower plastic plate has a plurality of through holes arrayed on the side near the negative electrode current collector, one of the through holes arrays has an arc-shaped limiting plate on one side, and the negative electrode current collector has a plurality of arc-shaped notches on the side, one of the arc-shaped notches being fitted and limited by the arc-shaped limiting plate.

[0022] Preferably, the negative electrode substrate and the inner side of the lower plastic plate are abutted by a rubber ring and a riveted electrode post.

[0023] Preferably, an upper plastic plate and a riveting block are sequentially provided on the side of the negative electrode substrate away from the lower plastic plate;

[0024] The negative electrode substrate is provided with an explosion-proof hole that communicates with the through hole array. An explosion-proof valve patch is embedded on the side of the explosion-proof hole away from the lower plastic plate, and an explosion-proof valve is embedded on the side of the explosion-proof hole closer to the lower plastic plate.

[0025] This application proposes a cylindrical battery, including a negative electrode cover and a single-pass battery casing as described in the above embodiments.

[0026] Beneficial effects:

[0027] Completely eliminate traditional welding processes such as laser welding, ultrasonic welding, and resistance welding, thereby eliminating defects such as weld slag, incomplete welding, and weld burn-through from the source, and saving tedious steps such as weld slag cleaning and multiple bending and positioning.

[0028] Replacing the long, complex busbar with a circular busbar of the same diameter allows for a flat connection without taking up additional axial height; eliminating the bending structure and welding safety distance frees up approximately 11mm of axial space for larger cells such as the 40135, which can increase the core length and improve the volumetric energy density by approximately 8.9%.

[0029] The core, conductive adhesive, busbar, and terminal post form a short-distance direct conductive path, reducing multi-level connection interfaces and riveting links, significantly reducing DC internal resistance (DCIR), and improving the cell's rate performance, fast charging capability, and cycle life.

[0030] The busbar and housing surfaces are roughened and combined with electrolyte-resistant and high-temperature-resistant conductive adhesive to improve bonding strength and conductivity reliability. The center of the busbar adopts a threaded elastic telescopic structure to compensate for the core height tolerance, maintain continuous bonding pressure, and prevent it from falling off or failing over long-term use.

[0031] Using low-temperature conductive adhesive for connection, eliminating the need for high-temperature welding, it is perfectly compatible with composite current collector cells containing insulating polymer layers such as PET and PI, solving the industry pain point of not being able to be traditionally welded, and supporting the industrialization of the next generation of high-safety battery cells. Attached Figure Description

[0032] Figure 1 This invention provides a three-dimensional structural schematic diagram of the negative electrode cover plate from one perspective.

[0033] Figure 2 This invention provides a three-dimensional structural schematic diagram of the negative electrode cover plate from another perspective.

[0034] Figure 3 This invention provides a schematic cross-sectional view of the negative electrode cover plate.

[0035] Figure 4 This invention provides a three-dimensional structural schematic diagram of the upper plastic sheet from one perspective;

[0036] Figure 5 This invention provides a three-dimensional structural schematic diagram of the upper plastic sheet from another perspective;

[0037] Figure 6 This invention provides a three-dimensional structural diagram of the negative electrode current collector from one perspective;

[0038] Figure 7This invention provides a three-dimensional structural schematic diagram of the negative electrode current collector from another perspective;

[0039] Figure 8 A schematic diagram of the three-dimensional structure of the riveted pole is provided for this invention;

[0040] Figure 9 This invention provides a schematic diagram of the three-dimensional structure of the lower plastic sheet;

[0041] Figure 10 This invention provides another three-dimensional structural schematic diagram of the lower plastic sheet;

[0042] Figure 11 This invention provides a three-dimensional structural schematic diagram of the negative electrode substrate from one perspective;

[0043] Figure 12 This invention provides a three-dimensional structural schematic diagram of the negative electrode substrate from another perspective;

[0044] Figure 13 A three-dimensional structural diagram of a single-channel battery casing is provided for this invention.

[0045] Figure label:

[0046] 1. Negative electrode current collector; 2. Riveted terminal post; 3. Negative electrode substrate; 4. Lower plastic plate; 5. Protruding structure; 6. Single-channel battery casing; 7. Support rib; 8. Through-hole array; 9. Arc-shaped limiting plate; 10. Arc-shaped notch; 11. Rubber ring; 12. Upper plastic plate; 13. Riveted pressure block; 14. Explosion-proof hole; 15. Explosion-proof valve patch; 16. Explosion-proof valve. Detailed Implementation

[0047] To make the technical solution of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0048] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art. The terms "including" and similar expressions used herein mean that the element or object preceding the term covers the element or object listed after the term and its equivalents, but do not exclude other elements or objects.

[0049] In response to the problems existing in the current technology, such as Figure 1-13As shown, a negative electrode cover plate is proposed, which is disposed at one end of the negative electrode of the single-pass battery casing 6, including: a circular negative electrode current collector 1, a riveted electrode post 2, a negative electrode substrate 3 and a lower plastic plate 4.

[0050] The negative electrode current collector 1 is connected to the battery core (not shown in the figure) disposed in the single-pass battery housing 6;

[0051] The negative electrode current collector 1 has a protruding structure 5 at the center of one side, and a riveted pole post 2 is provided on one side of the negative electrode current collector 1.

[0052] The lower plastic plate 4 is located on the side of the negative electrode current collector 1 away from the battery core, and the negative electrode substrate 3 is located on the side of the lower plastic plate 4 away from the negative electrode current collector 1.

[0053] The negative electrode substrate 3 and the lower plastic plate 4 are sleeved on the outside of the riveted electrode post 2;

[0054] The protruding structure 5 is embedded in the groove at one end of the riveted pole 2 and welded and fixed.

[0055] like Figure 10 In the middle, two positioning blocks are provided on one side of the lower plastic plate 4, corresponding to... Figure 11 In the middle, the negative electrode substrate 3 has a positioning groove on one side corresponding to the two positioning blocks to achieve accurate positioning.

[0056] In some specific embodiments, the negative electrode current collector 1 is electrically connected to the battery core disposed within the single-channel battery housing 6 via conductive adhesive (not shown in the figure); the battery core is placed inside the single-channel battery housing 6, such as... Figure 13 The other end of the battery casing is provided with an injection hole. This injection hole is located at the center of the single-pass casing and is used for injecting electrolyte through the center hole of the winding core. The diameter of the injection hole is ±2mm of the diameter of the center hole of the winding core, preferably 2mm to 6mm.

[0057] It eliminates the need for a separate electrolyte injection hole in the cover plate, which is required in traditional batteries, thus simplifying the cover plate structure; it has high electrolyte injection efficiency and uniform electrolyte wetting; after injection, it can be directly sealed at the positive terminal (such as by laser welding) without the need for an additional electrolyte injection plug.

[0058] The lower plastic plate 4 and the negative electrode current collector 1 are not only applicable to the laser-sealed aluminum-cased cylindrical battery structure, but also to the grooved steel-cased cylindrical battery structure, etc.

[0059] The structure includes, but is not limited to, cylindrical batteries with different diameters (21-60mm), different heights (60-200mm), and different casing materials (steel casing, aluminum casing, etc.).

[0060] The conductive adhesive coating thickness is 0.05mm to 0.5mm. The conductive adhesive is a conventional conductive adhesive, used to connect the composite current collector electrode to the core, achieving conductive connection without the need for tab welding. This conductive adhesive connection replaces welding, is compatible with composite current collector (PET / PI insulation layer) cells, and achieves conductivity without the need for roll welding.

[0061] In some specific embodiments, the protruding structure 5 is a threaded elastic buffer metal structure.

[0062] In some specific embodiments, the protruding structure 5 has a height of 0.2mm to 1.5mm and an axial expansion / contraction range of 0.2mm to 1.5mm. The threaded or helical structure of the protruding structure 5 has axial elastic expansion / contraction capability during assembly and pressing to compensate for the height tolerance of the core. The specific three-dimensional material of the protruding structure 5 is a conventional metal telescopic tube.

[0063] The protruding structure 5 is an elastic telescopic structure that generates axial compensation force during assembly and pressing, continuously pressing the conductive adhesive and the core together. This elastic structure compensates for core height tolerances, preventing poor contact.

[0064] In some specific embodiments, the side of the negative electrode current collector 1 that is connected to the conductive adhesive is a roughened surface;

[0065] The surface roughness is Ra1um~10um.

[0066] The roughening treatment can be achieved through processes such as sandblasting, laser roughening, chemical etching, or mechanical polishing.

[0067] Increasing the microscopic specific surface area of ​​the manifold allows the conductive adhesive to embed into microscopic depressions, forming a mechanical interlock after curing, while simultaneously increasing the effective conductive contact area. This significantly improves the adhesive strength and peel resistance of the conductive adhesive, reduces contact resistance, and prevents delamination under vibration or thermal shock conditions.

[0068] In some specific embodiments, the lower plastic plate 4 has multiple supporting ribs 7 distributed along the circumferential direction on the side near the negative electrode current collector 1, with the number of supporting ribs 7 ranging from 4 to 16. The supporting ribs are used to transmit pressure to the negative electrode current collector during the conductive adhesive pressing process to prevent the negative electrode current collector from being suspended or deformed.

[0069] In some specific embodiments, the lower plastic plate 4 is provided with a plurality of through hole arrays 8 on the side near the negative electrode current collector 1, and an arc-shaped limiting plate 9 is provided on one side of one of the through hole arrays 8. The side of the negative electrode current collector 1 is provided with a plurality of arc-shaped notches 10, and one of the arc-shaped notches 10 is fitted and limited by the arc-shaped limiting plate 9.

[0070] In some specific embodiments, the inner sides of the negative electrode substrate 3 and the lower plastic plate 4 are abutted by a rubber ring 11 and a riveted electrode post 2. This elastic seal blocks the electrolyte passage. The sealing is reliable, and the insulation is safe.

[0071] In some specific embodiments, an upper plastic plate 12 and a riveting block 13 are sequentially provided on the side of the negative electrode substrate 3 away from the lower plastic plate 4; all stacked components are axially pressed together. The structure is stable and resistant to vibration and impact.

[0072] Figure 12 The negative electrode substrate 3 has a cross-shaped groove on one side. Figure 4 The bottom of the upper plastic sheet has protrusions that correspond to the cross-shaped grooves for positioning.

[0073] The negative electrode substrate 3 has an explosion-proof hole 14 communicating with the through-hole array 8. An explosion-proof valve patch 15 is embedded on the side of the explosion-proof hole 14 away from the lower plastic plate 4, and an explosion-proof valve 16 is embedded on the side of the explosion-proof hole 14 closer to the lower plastic plate 4. This structure provides overpressure rupture relief, improving battery safety. The principle of this structure is to create a smooth air passage from the inside of the core to the explosion-proof valve. This enhances battery safety performance and avoids the risk of explosion due to internal short circuits or thermal runaway.

[0074] This application proposes a cylindrical battery, including a negative electrode cover and a single-pass battery casing 6 as described in the above embodiments.

[0075] Example 1: Fabrication and Comprehensive Performance Testing of 40135 Aluminum-Cased Cylindrical Cells

[0076] 1. Objective: To integrate and verify the superior comprehensive performance of the high-capacity, high-power 40135 battery cells prepared using the technology of this invention.

[0077] 2. Specific implementation details:

[0078] Cell specifications: 40135 aluminum-cased cylindrical lithium-ion battery (diameter 40mm, height 135mm), designed capacity 15Ah, target applications are energy storage or power tools, positive electrode material is lithium iron phosphate (LFP) or high-power ternary, negative electrode is graphite.

[0079] Preparation process:

[0080] After the bare cell (all tabs) is prepared, the conductive adhesive prepared in Example 1 is uniformly coated on the surface of its two tabs using a wide-width scraper or precision spraying equipment, with a coating thickness of 150±20μm.

[0081] The battery cell is placed into a single-channel aluminum shell (40mm inner diameter, lightweight), and one end is pressed and pre-fixed to the bottom of the shell.

[0082] A circular aluminum busbar (with reinforcing ribs and a central boss, 40mm in diameter) is placed at the other end of the battery cell.

[0083] Apply adhesive to the surface of the busbar boss and the groove of the pole post on the upper cover plate.

[0084] Assemble the cover plate assembly (integrated explosion-proof valve) to ensure accurate positioning and fit between the boss and the groove.

[0085] Laser sealing welding is performed on the aluminum shell and the aluminum (or nickel-plated steel) cover plate.

[0086] The entire battery cell was placed in a 110°C circulating air oven and baked for 36 hours to ensure that the bulk adhesive was fully and uniformly cured.

[0087] The test comparison data is as follows:

[0088]

[0089] Example 2: 40135 aluminum-cased cylindrical battery cell with a minimalist structure

[0090] 1. Purpose: To demonstrate the multiplier effect of minimalist structural design in achieving space saving and assembly simplification in large-size battery cells.

[0091] 2. Specific implementation details:

[0092] Comparison of structural parameters:

[0093] Traditional structure: Employs a large, elongated or multi-branched busbar (complex structure), requiring dozens of welding points for welding to the full-tie tabs, and high-current resistance welding or laser welding for connection to the pole. The housing has a double-through structure, with ample space (approximately 8-10mm) reserved at both ends for bending, welding, and heat dissipation.

[0094] The structure of this invention features a circular busbar (40mm in diameter) with the same diameter as the battery cell and a thickness of 0.8mm to enhance rigidity. The housing is a single-through aluminum shell (closed at one end, fully utilizing the lightweight and easily formable properties of aluminum). A deep groove is provided inside the electrode post of the upper cover plate.

[0095] Space saving calculation:

[0096] In traditional designs, the complex busbar structure and welding safety distance together occupy approximately 12mm of the axial height of the housing.

[0097] In this invention, the disc busbar is flat against the electrode tab, the adhesive layer is about 0.15mm thick, the boss is fitted into the cover plate groove, hardly occupies any additional axial height, and only about 1.0mm is reserved at the bottom of the housing for adhesive filling and insulation.

[0098] Conclusion: In the bus connection structure alone, this invention frees up approximately 11 mm of axial space for the 40135 cell. For a 40135 cell (total height 135 mm), this space can be used to increase the core stack or winding length by approximately 8.9%, or to add thicker electrodes to improve power performance. The absolute value of the space gain far exceeds that of smaller cells.

[0099] The above description is merely a specific implementation of the embodiments of the present invention, but the protection scope of the embodiments of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed in the embodiments of the present invention should be covered within the protection scope of the embodiments of the present invention. Therefore, the protection scope of the embodiments of the present invention should be determined by the protection scope of the claims.

Claims

1. A negative electrode cover plate, disposed at one end of the negative electrode of a single-pass battery casing (6), characterized in that, include: A circular negative current collector (1), a riveted electrode post (2), a negative electrode substrate (3), and a lower plastic plate (4). The negative electrode current collector (1) is connected to the battery core disposed in the single-pass battery housing (6); The negative electrode current collector (1) has a protruding structure (5) at the center of one side, and a riveted pole (2) is provided on one side of the negative electrode current collector (1). The lower plastic plate (4) is located on the side of the negative electrode current collector (1) away from the battery core, and the negative electrode substrate (3) is located on the side of the lower plastic plate (4) away from the negative electrode current collector (1). The negative electrode substrate (3) and the lower plastic plate (4) are sleeved on the outside of the riveted electrode post (2), and the inner sides of the negative electrode substrate (3) and the lower plastic plate (4) abut against the riveted electrode post (2) through the rubber ring (11); The protruding structure (5) is embedded in the groove at one end of the riveted pole (2) and welded and fixed.

2. The negative electrode cover plate according to claim 1, characterized in that, The negative electrode current collector (1) is electrically connected to the battery core disposed in the single-pass battery housing (6) through conductive adhesive. The conductive adhesive coating thickness is 0.05mm to 0.5mm.

3. The negative electrode cover plate according to claim 1, characterized in that, The protruding structure (5) is a threaded elastic buffer metal structure.

4. A negative electrode cover plate according to claim 3, characterized in that, The protruding structure (5) has a height of 0.2mm to 1.5mm and an axial extension range of 0.2mm to 1.5mm.

5. A negative electrode cover plate according to claim 2, characterized in that, The side of the negative electrode current collector (1) that is connected to the conductive adhesive is a roughened surface.

6. A negative electrode cover plate according to claim 5, characterized in that, The surface roughness is Ra1um~10um.

7. A negative electrode cover plate according to claim 2, characterized in that, The lower plastic plate (4) is provided with a number of support ribs (7) distributed along the circumference on the side near the negative electrode current collector (1), and the number of support ribs (7) is 4 to 16.

8. A negative electrode cover plate according to claim 2, characterized in that, The lower plastic plate (4) has multiple through-hole arrays (8) on one side near the negative electrode current collector (1), and one of the through-hole arrays (8) has an arc-shaped limiting plate (9) on one side. The side of the negative electrode current collector (1) has multiple arc-shaped notches (10), and one of the arc-shaped notches (10) fits and limits the arc-shaped limiting plate (9).

9. A negative electrode cover plate according to claim 1, characterized in that, The negative electrode substrate (3) is provided with an upper plastic plate (12) and a riveting block (13) on the side away from the lower plastic plate (4). The negative electrode substrate (3) is provided with an explosion-proof hole (14) that communicates with the through hole array (8). An explosion-proof valve patch (15) is embedded on the side of the explosion-proof hole (14) away from the lower plastic plate (4), and an explosion-proof valve (16) is embedded on the side of the explosion-proof hole (14) close to the lower plastic plate (4).

10. A cylindrical battery, characterized in that, Includes the negative electrode cover and single-pass battery casing (6) as described in any one of claims 1-9.

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