Square battery with improved r-angle stress

Abstract

This utility model relates to a square battery, and more particularly to a square battery with improved radius (R) corner stress; it belongs to the field of lithium-ion battery packaging technology. A square battery with improved radius (R) corner stress includes a square casing and a core disposed inside the square casing. The core has a stacked and wound structure, forming a first radius (R) corner between each of the four inner corners of the square casing. The square battery also includes a pair of support bodies, each support body including a first support portion adapted to the first radius (R). This utility model systematically optimizes the radius (R) corner stress defects of traditional square lithium-ion battery cores, and significantly improves the structural stability, cycle life, and safety reliability of the battery through multi-dimensional improvements such as support body constraints and core structure design.

Description

Technical Field

[0001] This utility model relates to a square battery, and more particularly to a square battery with improved R-angle stress; it belongs to the field of ion battery packaging technology. Background Technology

[0002] Square lithium-ion batteries, as rechargeable batteries encapsulated in aluminum or steel shells, are widely used in consumer electronics and power batteries due to their simple structure, high energy density, and strong adaptability. Their core structure consists of a shell (usually square) and an internal core, which is generally formed by winding alternating stacks of electrodes and separators. However, in current manufacturing processes, when two or four bare cores are installed into the shell, the semi-circular R-corners (i.e., the arc transition areas at the core edges) on both sides of the core exhibit significant structural defects: due to the lack of effective constraint and fixation in the R-corner area, the core is prone to deformation within the shell, leading to electrode wrinkling, abnormally increased electrode spacing, and consequently, the risk of lithium plating. Simultaneously, gaps between the R-corners can cause inward concavity on the sides of the cell shell, compromising the overall structural strength. These problems further lead to localized stress concentration at the R-corners during subsequent use, accelerating battery aging and severely impacting the product's cycle life and reliability. Therefore, improving the stress state at the R-corners of the core has become a key technical challenge for enhancing the performance and stability of square lithium-ion batteries.

[0003] For example, Chinese invention patent application No. 119381587A discloses a wound lithium-ion battery core, its manufacturing method, and a lithium-ion battery. This wound lithium-ion battery core includes: a positive electrode sheet, a negative electrode sheet, a separator, and two R-corner support structures; the two R-corner support structures are located at the two innermost R-corners of the battery core, and the positive and negative electrode unit sheets are stacked between the two R-corner support structures. While this core improves the stress distribution at the inner R-corners, the stress distribution problem at the outer R-corners still exists.

[0004] Utility model patent CN 217405558U discloses a square battery structure, which includes a core and a Mylar film. The Mylar film covers the sides and bottom of the core, with the sides of the core forming a radius (R-angle) with the Mylar film. Preferably, it also includes a plastic support at the R-angle. This patent improves the stability of the structure by using four plastic supports at the R-angle. However, the stability of this battery structure still needs improvement. Utility Model Content

[0005] This invention aims to solve the aforementioned problems by providing a square battery with improved R-angle stress. The invention effectively constrains R-angle deformation of the winding core by using a first support portion with a stacked winding structure adapted to the winding core and a second support portion adapted to a second R-angle structure between adjacent winding cores. Simultaneously, the positioning of the winding core via the winding core receiving groove and the covering and fixing of the Mylar film prevent electrode wrinkling and lithium plating, thereby improving battery reliability and lifespan.

[0006] The technical solution of this utility model to solve the above problems is as follows:

[0007] A square battery with improved radius (R) angle stress includes a square casing and a core disposed inside the square casing. The core is a stacked winding structure formed by winding continuous sheet-like cells around a virtual or solid sheet-like reference as a core. A first radius (R) angle is formed between the stacked winding structure and the four inner corners of the square casing. The square battery also includes a pair of supports, each support including a first support portion adapted to the first radius angle. The first support portion is supported between the stacked winding structure and the four inner corners of the square casing at the first radius angle.

[0008] As a preferred embodiment of the above technical solution, the core has multiple components, and a second R-angle is formed between adjacent cores; the support body further includes a second support portion adapted to the second R-angle; the second support portion is supported and disposed between adjacent cores at the second R-angle.

[0009] As a preferred embodiment of the above technical solution, the first support portion and the second support portion are integrally connected.

[0010] As a preferred embodiment of the above technical solution, the height of the support body is approximately equal to the height of the square shell.

[0011] In the above-mentioned technical solution of this utility model, in order to improve the stability of the battery structure, the height of the support body is approximately equal to the height of the square shell, that is, the upper end of the support body abuts against the top cover of the square shell, and the lower end of the support body abuts against the bottom shell of the square shell; in this way, when an external force is applied to the shell, the support body can protect the battery cells installed therein; and the support body can directly transfer the force on the top cover and the force on the bottom shell, thereby dispersing it on the overall shell and further improving the stability of the battery structure.

[0012] As a preferred embodiment of the above technical solution, the plurality of cores are disposed in a plurality of core receiving slots constrained by the pair of supports; adjacent core receiving slots are separated at their ends by the second support.

[0013] As a preferred embodiment of the above technical solution, all the winding cores and the pair of supports constitute a cell assembly; the square battery also includes a Mylar film, which covers the cell assembly.

[0014] As a preferred embodiment of the above technical solution, the square shell covers the Mylar membrane.

[0015] As a preferred embodiment of the above technical solution, each core includes at least 5 stacked winding layers.

[0016] As a preferred embodiment of the above technical solution, an adhesive patch is provided on the inner wall of the support body at the position corresponding to the core receiving groove to facilitate the fixing of the core.

[0017] As a preferred embodiment of the above technical solution, the square shell is an aluminum shell.

[0018] As a preferred embodiment of the above technical solution, the stacked winding structure is provided with an inner R-angle support.

[0019] In summary, this utility model has the following beneficial effects:

[0020] 1. This utility model systematically optimizes the stress defects of the R-corner of traditional square lithium-ion battery cores. Through multi-dimensional improvements such as support constraint, core structure design, and material synergy, it significantly improves the structural stability, cycle life, and safety reliability of the battery.

[0021] 2. The precise matching of the first support part with the first R-corner and the second support part with the second R-corner directly forms a physical constraint on the R-corner area of ​​the core, limiting the displacement or deformation of the core due to volume changes during charging and discharging. The problem of electrode wrinkling and increased spacing caused by the lack of constraint in the R-corner area in traditional solutions is effectively solved, and the risk of lithium plating is significantly reduced. The support inside the stacked winding structure further constrains the internal R-corner, preventing local deformation of the multi-layer electrode due to stress concentration inside, avoiding internal electrode wrinkling or breakage, and improving the overall structural integrity of the core.

[0022] 3. Multiple cores are confined within a core receiving groove enclosed by a first support and a second support. Adjacent receiving grooves are separated by the second support to ensure that the position, angle and height of each core are consistent. This standardized layout avoids uneven force on the R-angle caused by installation deviations of the cores, avoids squeezing between cores, and improves battery consistency.

[0023] 4. The adhesive on the inner wall of the core receiving groove further enhances the bonding strength between the core and the support, preventing the core from detaching from the support due to expansion / contraction during charge / discharge cycles, and maintaining long-term stable constraint of the R-corner area.

[0024] 5. The integrated design of the first support part and the second support part forms a continuous support frame. Compared with the split support body, its structural strength is higher and it can effectively resist the lateral stress generated by the cyclic expansion of the core, avoiding constraint failure caused by the breakage or deformation of the support body.

[0025] 6. The Mylar film-coated cell assembly isolates external moisture, dust and other contaminants, reducing the risk of electrode corrosion. On the other hand, it works in conjunction with the support to form a "soft constraint" on the entire core, alleviating mechanical stress under extreme operating conditions and extending battery cycle life.

[0026] 7. In summary, this utility model systematically solves the problems of electrode deformation, lithium plating, and structural instability caused by the force defects of the R-angle of traditional square lithium-ion batteries through innovative designs such as precise constraint of the R-angle of the support body, standardized positioning of the core receiving groove, and collaborative protection of the Mylar film. It significantly improves the cycle life, safety, reliability and energy density of the battery, and is suitable for scenarios with high requirements for structural stability and reliability, such as consumer electronics and power batteries. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of Example 1;

[0028] Figure 2 yes Figure 1 A magnified view of a portion of the image;

[0029] Figure 3 This is a partially enlarged view of Example 2;

[0030] In the diagram, the component names represented by each label are as follows:

[0031] 1-Square shell,

[0032] 2-Core,

[0033] 3-Support body,

[0034] 4-Mylar membrane,

[0035] 5-Adhesive,

[0036] 21-First R-angle,

[0037] 22-Second R angle,

[0038] 23-Inner R-angle support,

[0039] 30-Core receiving slot,

[0040] 31-First Support Section

[0041] 32-Second support section,

[0042] 33 - Flexible adhesive strip. Detailed Implementation

[0043] The present invention will be further explained below with reference to the accompanying drawings.

[0044] This specific embodiment is merely an explanation of the present invention and is not intended to limit the present invention. Any changes made by those skilled in the art after reading the specification of the present invention, as long as they are within the scope of the claims, will be protected by patent law.

[0045] Example 1

[0046] like Figures 1-2 As shown, a square battery with improved R-angle stress is composed of a square casing 1, four coils 2, a pair of supports 3, a Mylar film 4, and adhesive tape 5. Wherein:

[0047] like Figure 2 As shown, a pair of support bodies 3 form four side-by-side core receiving slots 30, with equal spacing between adjacent core receiving slots 30. Each support body 3 includes an integrally connected first support portion 31 and a second support portion 32. The core 2 is a stacked winding structure formed by winding continuous, thin-sheet-like electrical cells around a virtual or solid sheet-like reference as a core. A first radius angle 21 is formed between the stacked winding structure and the four inner corners of the square housing; a second radius angle 22 is formed between adjacent cores. The first support portion 31 is supported at the first radius angle 21 between the stacked winding structure and the four inner corners of the square housing 1; the second support portion 32 is supported at the second radius angle 22 between adjacent cores. The four cores 2 are respectively disposed within the four core receiving slots 30 and constrained. More importantly, all the cores 2 (four) and a pair of supports 3 are combined to form a battery cell assembly, which is covered by the Mylar film 4; the square housing 1 covers the Mylar film 4; and the adhesive 5 is disposed in the core receiving groove 30.

[0048] The square housing 1 is made of aluminum alloy and has a cuboid structure with four right angles and a smooth, burr-free inner wall. The core 2 is formed by winding continuous thin-sheet cells (positive electrode + separator + negative electrode alternately stacked) based on a virtual sheet, forming a stacked winding structure (≥5 layers), forming a first radius 21 with the inner wall of the square housing; an inner radius support 23 is provided inside. The support 3 includes an integrally connected first support part 31 and a second support part 32 (made of nylon 6). The first support part 31 adapts to the first radius 21, and the second support part 32 adapts to the second radius 22 between adjacent cores. The core receiving groove 30, surrounded by the first support part 31 and the second support part 32, is used to position each core 2. The Mylar film 4 is a 0.1mm thick polymer film located inside the housing, serving an insulating function. The adhesive 5 is a double-sided adhesive, pasted onto the inner wall of the core receiving groove 30 to fix the core 2.

[0049] Specifically, the core 2 is a stacked winding structure, formed by alternately stacking positive electrode sheets, separators, and negative electrode sheets and then winding them around a virtual reference. After winding, two inner R-angle supports 23 are inserted inside the core. During winding, the virtual reference is located at the center of the core, and the electrode sheets and separator naturally form an R-angle 21 with rounded edges during the winding process, which matches the first support part 31. At the same time, during the winding process, an inner R-angle with rounded edges is also naturally formed inside the core, and an inner R-angle support 23 of appropriate size is inserted.

[0050] The support 3 is a one-piece molded plastic part, specifically nylon 6, including:

[0051] 1) The first support part 31 is located at the four inner corners of the square shell 1. It has an L-shaped structure and is in clearance fit with the first R corner 21 of the core 2 (gap 0.1mm).

[0052] 2) The second support part 32 is located at the end of the adjacent core receiving groove 30. It is a recessed structure with an arc surface on the inner edge. It is integrally connected with the second support part 32 of the adjacent core, and a protruding structure is formed between the two. Therefore, the two adjacent core receiving grooves 30 are separated by the protruding structure.

[0053] Adhesive 5 is a double-sided adhesive. The release paper of the double-sided adhesive is peeled off before installation, and the adhesive is pressed to make it firmly bonded to the core 2.

[0054] The production process mainly includes the following steps:

[0055] 1. Core Preparation

[0056] The positive electrode, negative electrode, and separator are unwound in sequence, and the electrode is kept flat by the tension control system; the winding machine is started (50 rpm), and stopped after winding 7 layers; the electrode and separator are cut off, the core 2 is taken out, and the radius of the R-angle is checked; after the winding is completed, two inner R-angle supports 23 are inserted into the core 2.

[0057] 2. Shell Preparation

[0058] Mylar film 4 is hot-pressed onto one surface of an aluminum alloy plate; the aluminum alloy plate is then bent into a square battery casing with open ends.

[0059] 3. Core assembly

[0060] Place the core 2 into the core receiving groove 30 and press it to adhere the adhesive 5 to the core 2 and the adhesive 5 to the support body 3; then insert the battery cell assembly composed of the core 2 and the support body 3 into the square battery casing with open ends, ensuring that the four first support parts 31 are in clearance fit with the first R angle 21 (gap 0.1mm).

[0061] 4. Housing Encapsulation

[0062] The top cover and bottom shell are welded using a laser welding machine; after welding, X-ray inspection is performed to ensure there are no incomplete welds or missing welds.

[0063] Example 2

[0064] The only difference from Embodiment 1 is that the support in this embodiment is a split type, such as... Figure 3 As shown, it includes a first support portion 31 disposed at a first R-angle 21 and a second support portion 32 disposed at a second R-angle 22. Meanwhile, to facilitate the positioning of the second support portions 32 and their mutual support, flexible adhesive strips 33 are provided between adjacent second support portions 32 and between the first support portion 31 and the second support portion 32.

Claims

1. A square battery with improved radius (R) angle stress, comprising a square casing (1) and a core (2) disposed inside the square casing, wherein the core (2) is a stacked winding structure formed by winding continuous sheet-like cells around a virtual or solid sheet-like reference as a core, and the stacked winding structure forms a first radius (R) angle (21) between each of the four inner corners of the square casing; characterized in that: The square battery also includes a pair of supports (3), each support (3) including a first support portion (31) adapted to the first R-angle (21), the first support portion (31) being supported between the stacked winding structure at the first R-angle (21) and the four inner corners of the square shell (1).

2. The square battery having improved R-angle stress according to claim 1, wherein: The core (2) has multiple cores, and a second R-angle (22) is formed between adjacent cores; the support (3) also includes a second support part (32) adapted to the second R-angle (22), and the second support part (32) is supported between adjacent cores at the second R-angle (22).

3. The square battery of claim 2, wherein: The first support part (31) and the second support part (32) are integrally connected.

4. The square battery having an improved R-angle stress according to claim 2, wherein: The plurality of cores (2) are disposed in a plurality of core receiving slots (30) constrained by the pair of supports (3); adjacent core receiving slots (30) are separated at their ends by the second support (32).

5. The square battery having improved R-corner stress according to claim 4, characterized by: All the cores (2) and the pair of supports (3) constitute a cell assembly; the square battery also includes a Mylar film (4) which covers the cell assembly.

6. The square battery having improved R-corner stress according to claim 5, characterized by: The square shell (1) covers the Mylar membrane (4).

7. The square battery having improved R-angle stress according to claim 1, wherein: Each core (2) includes at least 5 stacked winding layers.

8. The square battery having improved R-corner stress according to claim 4, wherein: The inner wall of the support (3) is provided with adhesive tape (5) at the position corresponding to the core receiving groove (30) to facilitate the fixing of the core (2).

9. The square battery having improved R-corner stress according to claim 6, wherein: The square shell (1) is an aluminum shell.

10. The square battery having improved R-angle stress according to claim 1, wherein: The stacked winding structure is provided with an inner R-angle support (23).

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