Battery shell, battery and battery pack
By setting a wedge-shaped blue film overlap and an appropriate angle design on the curved surface of the battery casing corner, the problems of complex battery casing coating process and reduced energy density are solved, thereby improving battery energy density and production efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SUZHOU QINGTAO NEW ENERGY TECH CO LTD
- Filing Date
- 2025-04-30
- Publication Date
- 2026-05-08
AI Technical Summary
When existing battery casings are covered with a blue film, the overlapping parts of the blue film occupy space, resulting in a decrease in battery energy density. Furthermore, the covering process is complex and the production yield is low.
The overlapping part of the blue film is set on the corner curved surface of the battery casing and designed as a wedge structure with an inclination angle of 60° to 80° and an appropriate radius. The outer surface is provided with a rough layer to ensure that the cell fits the inner wall of the casing. The battery pack adopts a matrix arrangement.
It improves the energy density of the battery, enhances the reliability of the blue film coating, simplifies the coating process, improves production yield and space utilization, and reduces the cell displacement during vibration testing.
Smart Images
Figure CN224217562U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of battery technology, and in particular to battery casings, batteries and battery packs. Background Technology
[0002] In the field of battery manufacturing, insulation protection is crucial. Currently, a common practice is to coat the battery casing with a blue film to prevent short circuits caused by electrical connections between the battery and other structures.
[0003] like Figure 1 and Figure 2 As shown, the industry widely adopts a loop-shaped wrapping method to cover the blue film 200' on the shell body 100'. This method involves connecting the two ends of the blue film 200' to form an overlapping part, thereby achieving full coverage of the side wall of the shell body 100'.
[0004] However, this method has obvious drawbacks. Because the overall battery size must meet production requirements, when the length and width of the main casing 100' are fixed, the overlapping portion of the blue film 200' will occupy a certain amount of space in the width direction of the main casing 100'. This not only limits the size of the main casing 100' but also affects the size of the battery cells inside, ultimately leading to a reduction in the battery's energy density. Utility Model Content
[0005] The purpose of this utility model is to provide a battery casing, a battery, and a battery pack to improve the energy density of the battery, enhance the reliability of the blue film coating, improve the production yield, simplify the coating process, and improve the structure and method of blue film coating of the battery casing.
[0006] To achieve this objective, the present invention adopts the following technical solution:
[0007] A battery casing includes a casing body and a blue film. The blue film covers the outer side wall of the casing body. The outer side wall of the casing body has a plurality of outer shell planes, and every two outer shell planes are connected by a transition surface. One of the transition surfaces is defined as a corner surface. The first end of the blue film partially overlaps with the last end of the blue film to form an overlapping portion. The overlapping portion is disposed on the corner surface, and the overlapping portion does not exceed the adjacent outer shell plane.
[0008] As an optional technical solution for the battery casing, the end face of the first end of the blue film is inclined, the thickness of the first end of the blue film first increases and then remains constant in the direction towards the tail end of the blue film, and the tail end of the blue film is in contact with the end face of the first end of the blue film.
[0009] As an optional technical solution for the battery casing, the tilt angle of the first end face of the blue film is θ, where 60° < θ < 80°.
[0010] As an optional technical solution for the battery casing, the main body of the casing is rectangular, the radius of the transition surface excluding the corner surface is R1, and the radius of the corner surface is R2. <R2。
[0011] As an optional technical solution for the battery casing, R2≤0.5W, where W is the width of the casing body.
[0012] As an optional technical solution for the battery casing, the outer surface of the casing body is provided with a rough layer.
[0013] The battery includes a cell and the aforementioned battery casing. The sidewalls of the battery casing have a uniform thickness. The cell is disposed within the battery casing, and the inner wall surface corresponding to the corner curved surface is adapted to fit and adhere to the cell portion.
[0014] As an optional technical solution for the battery, the cell is a wound cell, which includes a straight section and two arc sections. The two arc sections are respectively disposed at both ends of the straight section, and the inner wall surface corresponding to the corner curved surface is adapted and fitted to one of the arc sections.
[0015] As an optional technical solution for the battery, the radius of the corner surface is R2, which is half the thickness of the wound cell.
[0016] The battery pack comprises several of the aforementioned batteries, all of which are arranged in a matrix.
[0017] The beneficial effects of this utility model are:
[0018] This battery casing design optimizes space utilization by limiting the overlapping portion of the blue film to a curved corner surface and ensuring it does not exceed the plane of the adjacent outer casing. This avoids the blue film occupying additional space on the battery surface, guarantees the effective volume of the battery cells placed inside the casing, and maximizes the size of the battery cells that can be accommodated within the casing, thus improving the energy density of the battery using this casing. The curved corner surface acts as a natural buffer zone for stress concentration areas, providing an arc transition for the overlapping portion. This allows the bonding interface of the overlapping portion to withstand uniform shear force, reducing the risk of warping at the edges of the blue film, preventing cracking at the beginning and end of the bonding section, and enhancing the reliability of the coating. Limiting the overlapping portion to not exceeding the plane of the adjacent outer casing ensures the standardized implementation of the coating process, reduces rework rates, and improves processing adaptability and production yield. At the same time, these improvements simplify the alignment accuracy requirements in the coating process, facilitate the development of standardized coating path planning, and help improve the operability of the manufacturing process.
[0019] The uniform wall thickness design of this battery ensures a consistent gap between the cell and the inner wall of the casing, improving the effective filling rate of the cell, preventing localized compression, and eliminating stress concentration points, thus contributing to improved fatigue life. The arc-shaped gap formed between the inner wall surface corresponding to the corner curved surface and the cell serves as an electrolyte storage area, increasing the electrolyte retention and mitigating electrolyte consumption during charging and discharging, thereby improving space utilization. The curved surface adaptation structure design limits the gap between the cell and the casing, reducing cell displacement during vibration testing.
[0020] The battery pack uses a matrix arrangement of batteries. Because the overlapping parts do not occupy space in the battery arrangement direction, the accumulated error of module assembly is eliminated, compact stacking is achieved, volume utilization is improved, and the energy density of the battery pack is increased. Attached Figure Description
[0021] Figure 1 This is a cross-sectional view of an existing battery casing;
[0022] Figure 2 yes Figure 1 A magnified view of part A in the image;
[0023] Figure 3 This is a cross-sectional view of the battery provided in an embodiment of the present utility model;
[0024] Figure 4 yes Figure 3 A magnified view of part B in the image;
[0025] Figure 5 This is a top view of the wound battery cell provided in this embodiment of the utility model;
[0026] Figure 6 This is a cross-sectional view of a battery with wound cells provided in an embodiment of the present invention;
[0027] Figure 7 This is a top view of the stacked battery cell provided in this embodiment of the present invention;
[0028] Figure 8 This is a cross-sectional view of a battery with stacked cells provided in an embodiment of the present invention.
[0029] Figure 1 and Figure 2 middle:
[0030] 100', Main body of the casing; 200', Blue film;
[0031] Figures 3 to 8 middle:
[0032] 100. Main body of the casing; 101. Corner curved surface; 200. Blue film; 300. Battery cell; 301. Winded battery cell; 3011. Straight section; 3012. Arc section; 302. Stacked battery cell. Detailed Implementation
[0033] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.
[0034] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The terms "first position" and "second position" refer to two different positions. Moreover, "above," "on top of," and "over" the first feature in relation to the second feature includes the first feature directly above and diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "under," and "below" the first feature in relation to the second feature includes the first feature directly below and diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0035] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0036] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.
[0037] like Figure 3 and Figure 4 As shown, this embodiment provides a battery housing, including a housing body 100 and a blue film 200. The blue film 200 covers the outer side wall of the housing body 100. The outer side wall of the housing body 100 has a plurality of outer shell planes, and each pair of outer shell planes is connected by a transition surface. One of the transition surfaces is defined as a corner surface 101. The first end of the blue film 200 and the last end of the blue film 200 partially overlap to form an overlapping portion. The overlapping portion is disposed on the corner surface 101, and the overlapping portion does not exceed the adjacent outer shell plane.
[0038] This battery casing design optimizes space utilization by limiting the overlapping portion of the blue film 200 to the corner curved surface 101 and ensuring it does not exceed the adjacent outer shell plane. This avoids the blue film 200 occupying additional space on the battery surface, guaranteeing the effective volume of the battery cell 300 placed inside the casing body 100. The corner curved surface 101 acts as a natural buffer zone for stress concentration areas, providing an arc transition for the overlapping portion. This allows the bonding interface of the overlapping portion to withstand uniform shear force, reducing the risk of edge warping of the blue film 200, preventing cracking at the beginning and end of the bonding portion, and enhancing the reliability of the coating. Limiting the overlapping portion to not exceeding the adjacent outer shell plane ensures standardized implementation of the coating process, reduces rework rates, and improves processing adaptability and production yield. Furthermore, these improvements simplify the alignment accuracy requirements in the coating process, facilitate the development of standardized coating path planning, and contribute to improving the operability of the manufacturing process.
[0039] In this embodiment, the end face of the first end of the blue film 200 is inclined, and the thickness of the first end of the blue film 200 first increases and then remains constant in the direction towards the tail end of the blue film 200. The tail end of the blue film 200 is in contact with the end face of the first end of the blue film 200. Specifically, the tail end of the blue film 200 is completely in contact with the end face of the first end of the blue film 200.
[0040] The design of the Blue Film 200, with its initial thickness gradually increasing and then maintaining a constant thickness, forms a wedge-shaped embedding structure. This increases the contact pressure between the front and rear ends of the Blue Film 200, creating a progressive fit with the inner wall of the rear end. This results in a continuous and closed connection interface, reducing air bubbles and wrinkles during the wrapping process. The complete fit between the rear and front ends of the Blue Film 200 effectively eliminates the stepped gaps created by traditional flat-cut ends, enhancing interface sealing and optimizing structural fit. Furthermore, the gradient design, which increases thickness and then maintains it, absorbs tensile stress generated during the wrapping process, dispersing mechanical stress and resulting in a more uniform stress distribution at the joint, preventing tearing of the Blue Film 200 at corners due to sudden stress changes. Simultaneously, the constant thickness section provides a reliable positioning reference, improving the positioning accuracy of automated wrapping equipment and ensuring process stability. This design, while ensuring the tear resistance of the front end of the Blue Film 200, prevents edge warping at the rear end due to sudden thickness changes, achieving a balance in mechanical performance.
[0041] Furthermore, the tilt angle of the first end face of the Blue Membrane 200 is θ, where 60° < θ < 80°.
[0042] The tilt angle θ is limited to 60° to 80° to achieve the optimal balance point of adhesive layer shear strength, maximizing the contact area at both ends while avoiding edge curling caused by an excessively small angle, thus optimizing adhesion strength. This angle range is compatible with the ductility of mainstream blue film materials, meets the parameter requirements of corresponding mainstream blue film slitting equipment, ensures a balance between cut quality and production efficiency, guarantees stability in mass production, and demonstrates process feasibility. This angle range also ensures a small surface height difference after coating, meeting the battery's appearance requirements and guaranteeing a smooth finish.
[0043] For example, the main body 100 of the housing is rectangular, and the radius of the transition surface other than the corner surface 101 is R1, and the radius of the corner surface 101 is R2. <R2。
[0044] The corner curved surface 101 has a larger radius R2, which increases the overlapping area of the blue film 200, ensuring the space utilization rate in the width direction of the main body 100 of the shell, meeting the structural reliability requirements, and achieving precise dimensional control; the other transition curved surfaces have smaller radii R1, which ensure the structural strength at the corners, retain the internal corner space of the main body 100 of the shell for storing electrolyte, and extend the cycle life.
[0045] Furthermore, R2≤0.5W, where W is the width of the shell body 100.
[0046] The upper limit of R2 is half of the width of the housing body 100, so as to prevent the radius from being too large and affecting the vertical support compressive resistance at the corner surface 101 of the housing body 100, and at the same time prevent the internal space of the housing body 100 from being affected. If the internal space is affected, the battery energy density will be small. Therefore, the overall structural strength of the housing body 100 and the overall energy density of the battery can be taken into account.
[0047] Specifically, 3.0 mm < R1 < 4.0 mm; the radius of the corner surface 101 is R2, 4.0 mm < R2 ≤ 0.5W, and W > 8.0 mm.
[0048] In this embodiment, the thickness of the overlapping part of the blue film 200 does not exceed 10% of the thickness of the side wall of the housing body 100.
[0049] By limiting the ratio of the overlapping thickness to the side wall thickness, it is possible to avoid assembly interference of the battery module due to the thickening of the film wrapping. The design of thinning the overlapping layer can reduce the local thermal resistance difference of the blue film 200, avoid uneven heat dissipation caused by local overthickness, improve the battery heat dissipation uniformity, realize thermal management optimization, and ensure mechanical properties.
[0050] In this embodiment, the outer surface of the housing body 100 is provided with a rough layer. Exemplarily, the outer side wall of the housing body 100 is anodized.
[0051] The dense oxide layer formed by anodic oxidation forms a microporous structure, enhances the adhesive penetration and anchoring effect of the blue film 200, and improves the bonding strength between the blue film 200 and the housing body 100; the dense oxide layer also has corrosion resistance, which can avoid the peeling of the blue film 200 caused by the corrosion of the housing body 100 when the electrolyte leaks. The material of the housing body 100 is aluminum alloy or aluminum alloy composite material, which can realize the lightweight design of the battery housing.
[0052] This embodiment also provides a battery, including a battery cell 300 and the above-mentioned battery housing. The thickness of the side wall of the battery housing is equal everywhere. The battery cell 300 is arranged in the battery housing, and the inner wall surface corresponding to the corner surface 101 is partially adapted and fitted to the battery cell 300.
[0053] The equal wall thickness design of this battery ensures that the gap between the battery cell 300 and the inner wall of the housing body 100 is uniform, improves the effective filling rate of the battery cell 300, avoids local extrusion, and can also eliminate stress concentration points, which helps to improve the fatigue life. The arc-shaped gap formed between the inner wall surface corresponding to the corner surface 101 and the battery cell 300 serves as an electrolyte storage area, increasing the electrolyte retention, alleviating the problem of electrolyte consumption during charge and discharge, and improving the space utilization rate. The design of the curved surface adaptation structure can limit the gap between the battery cell 300 and the housing body 100, reducing the displacement of the battery cell during the vibration test.
[0054] Such as Figure 5and Figure 6 As shown, in a preferred embodiment of this example, the battery cell 300 is a wound battery cell 301. The wound battery cell 301 includes a straight section 3011 and two arc sections 3012. The two arc sections 3012 are respectively disposed at both ends of the straight section 3011. The inner wall surface corresponding to the corner curved surface 101 is adapted to fit and adhere to one of the arc sections 3012.
[0055] The wound cell 301 is a cell formed by stacking positive and negative electrode sheets and a separator together in a cross manner and then rolling them up from one end. The specific structure and working principle of the wound cell 301 are common knowledge in the field and are not the focus of this application, so they will not be described in detail here.
[0056] The arc segment 3012 fits snugly against the inner wall of the corner curved surface 101, resulting in a high degree of curvature matching. This helps to further reduce cell displacement during vibration testing, reduces the risk of collision between the end of the wound cell 301 and the main body 100 of the casing, and prevents the core from collapsing. These constraints ensure a uniform distribution of core expansion stress, facilitating a reduction in cyclic expansion rate. The arc-shaped end of the wound cell 301, adapted to the large-radius corner curved surface 101, increases the effective volume ratio of the wound cell 301, thereby improving energy density.
[0057] like Figure 7 and Figure 8 As shown, in another embodiment of this example, the battery cell 300 is a laminated battery cell 302, and the inner wall surface corresponding to the corner curved surface 101 is adapted to fit and adhere to one side portion of the laminated battery cell 302.
[0058] The specific structure and working principle of the laminated cell 302 are common knowledge in the field and are not the focus of this application. Therefore, they will not be elaborated here.
[0059] By fitting the inner wall of the corner curved surface 101 to the side of the laminated cell 302, the shear stress problem of the housing body 100 on the edge of the laminated cell 302 is solved. The buffer space at the corner retains expansion margin, improves cycle capacity retention, and adapts to the charging and discharging deformation of the laminated cell 302. At the same time, it also increases the effective volume ratio of the laminated cell 302 and improves energy density.
[0060] In this embodiment, R2 is half the thickness of the wound cell 301. The above limitation makes the arc segment 3012 of the wound cell 301 better match the inner wall of the corner curved surface 101, that is, it will not cause waste of the internal space of the housing, and it can form a larger overlapping area for the bonding space at the beginning and end of the blue film 200, which is not easy to lift.
[0061] In addition, multiple wound battery cells 301 can be disposed within the housing body, and each wound battery cell 301 has the same thickness. It can be understood that the radius of the corner curved surface 101 is half the thickness of a single wound battery cell 301.
[0062] For example, the width of the housing body is 90.0 mm, and three wound cells 301 are provided. The thickness of a single wound cell 301 is 30.0 mm. Then the radius of the two arc segments 3012 of the wound cell 301 is 15.0 mm, and the radius of the corner curved surface 101 is 15.0 mm. The corner curved surface 101 can match well with the arc segment 3012 of the wound cell 301 that is close to it.
[0063] This embodiment also provides a battery pack, which includes several of the batteries described above, all of which are arranged in a matrix.
[0064] The battery pack uses a matrix arrangement of batteries. Because the overlapping parts do not occupy space in the battery arrangement direction, the accumulated error of module assembly is eliminated, compact stacking is achieved, volume utilization is improved, and the energy density of the battery pack is increased.
[0065] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.
Claims
1. A battery casing, characterized in that, The device includes a housing body (100) and a blue membrane (200). The blue membrane (200) covers the outer side wall of the housing body (100). The outer side wall of the housing body (100) has a plurality of outer shell planes, and each pair of outer shell planes is connected by a transition surface. One of the transition surfaces is defined as a corner surface (101). The first end of the blue membrane (200) partially overlaps with the last end of the blue membrane (200) to form an overlapping portion. The overlapping portion is disposed on the corner surface (101), and the overlapping portion does not exceed the adjacent outer shell plane.
2. The battery casing according to claim 1, characterized in that, The first end face of the blue film (200) is inclined, and the thickness of the first end of the blue film (200) first increases and then remains constant in the direction toward the tail end of the blue film (200). The tail end of the blue film (200) is in contact with the first end face of the blue film (200).
3. The battery casing according to claim 2, characterized in that, The tilt angle of the first end face of the blue membrane (200) is θ, where 60° < θ < 80°.
4. The battery casing according to claim 1, characterized in that, The main body (100) of the shell is rectangular. The radius of the transition surface, excluding the corner surface (101), is R1, and the radius of the corner surface (101) is R2. <R2。 5. The battery casing according to claim 4, characterized in that, R2≤0.5W, where W is the width of the main body (100) of the shell.
6. The battery casing according to any one of claims 1-5, characterized in that, The outer surface of the housing body (100) is provided with a rough layer.
7. A battery, characterized in that, The battery includes a battery cell (300) and a battery housing according to any one of claims 1-6, wherein the sidewalls of the battery housing have the same thickness everywhere, the battery cell (300) is disposed inside the battery housing, and the inner wall surface corresponding to the corner curved surface (101) is partially adapted and fitted to the battery cell (300).
8. The battery according to claim 7, characterized in that, The battery cell (300) is a wound battery cell (301). The wound battery cell (301) includes a straight section (3011) and two arc sections (3012). The two arc sections (3012) are respectively disposed at both ends of the straight section (3011). The inner wall surface of the corner curved surface (101) is adapted and fitted to one of the arc sections (3012).
9. The battery according to claim 8, characterized in that, The radius of the corner surface (101) is R2, which is half the thickness of the wound cell (301).
10. A battery pack, characterized in that, The battery includes any one of claims 7-9, all of which are arranged in a matrix.