Soft-pack casing, soft-pack battery and electrical device

Abstract

This utility model discloses a soft-pack housing, a soft-pack battery, and an electrical device, relating to the field of soft-pack battery technology. The soft-pack housing includes an aluminum-plastic film and a first protective sheet. The aluminum-plastic film includes a first shell and a second shell. A first cavity is provided inside the first shell, facing away from the second shell. The edges of the first shell and the second shell are sealed together to form an encapsulation cavity. The first protective sheet is fixed to the inner surface of the first shell and is placed in the corner area of ​​the first shell, and A1≥π[(0.6±0.1)B1] 2 Where A1 is the area of ​​the first protective sheet and B1 is the depth of the first cavity. The soft-pack housing includes an aluminum-plastic film and a protective sheet. The protective sheet is fixed to the corner area of ​​the first housing and designed with a specific relationship between its area and the cavity depth to disperse the stress concentration caused by the expansion of the electrode material, suppress the cracking of the aluminum-plastic film at the corners, and has the advantages of improving battery reliability and cycle life.

Description

Technical Field

[0001] This utility model belongs to the field of soft-pack battery technology, and particularly relates to a soft-pack casing, a soft-pack battery, and an electrical device. Background Technology

[0002] In the manufacturing process of pouch lithium-ion batteries, aluminum-plastic film of a specific thickness is currently widely used as the packaging material. This material first undergoes a precise deep drawing process to form a recessed shell with a specified depth and shape to accommodate the core formed by winding or stacking positive and negative electrode sheets and a separator. Subsequently, through a series of critical processes including top sealing, side sealing, electrolyte injection, formation, and secondary sealing, the battery packaging is finally completed. However, with the market's continuous increase in battery energy density requirements, high-energy-density systems (especially those using silicon-containing negative electrode materials such as silicon-carbon or silicon suboxide) experience significant volume expansion of their negative electrode materials during subsequent charge-discharge cycles (the theoretical expansion rate of silicon can reach over 300%). This repeated and drastic volume change generates continuous mechanical stress on the packaging structure, especially the aluminum-plastic film shell in areas of abrupt geometric changes such as corners and bends. When the local stress exceeds the tolerance limit of the aluminum-plastic film, it can easily cause material delamination, cracking, or even electrolyte leakage at the corners—a phenomenon commonly referred to in the industry as "corner breakage." This issue not only affects the appearance of the battery, but may also lead to accelerated performance degradation and increased safety risks, becoming one of the key technical bottlenecks restricting the reliability and cycle life of high-energy-density pouch batteries.

[0003] The root cause of corner breakage in aluminum-plastic films is not simply the material's inherent ductility or the limitations of deep-drawing processes, but primarily due to the dramatic volume expansion of electrode materials (especially silicon-containing anodes) during battery charge-discharge cycles. Current pouch cell manufacturing processes lack substantial protective mechanisms against mechanical damage to the aluminum-plastic film caused by expansion stress, whether in shell structure design, packaging technology, or material selection. Specifically, under repeated expansion-contraction cyclic loads, the corner areas of the aluminum-plastic film experience tension far exceeding their fatigue strength due to geometric stress concentration, leading to delamination or tearing of the nylon / PP composite layer. This failure mode not only directly causes electrolyte leakage and performance degradation but also harbors the risk of thermal runaway. Therefore, effectively suppressing corner breakage through material modification (such as developing highly ductile composite films), structural optimization (designing stress-concentration-resistant shells), or process innovation (introducing stress buffer layers) has become a key issue in improving the reliability of high-energy-density pouch cells, requiring breakthroughs in research and engineering. Summary of the Invention

[0004] The technical problem to be solved by this utility model is: to address the issue that the electrodes of existing soft-pack battery cells easily rupture the aluminum-plastic film at the four corners during charging and discharging, and to provide a soft-pack shell, a soft-pack battery, and an electrical device.

[0005] To address the aforementioned problems, this utility model provides a flexible housing, comprising an aluminum-plastic film and a first protective sheet. The aluminum-plastic film includes a first housing and a second housing. A first cavity is formed within the first housing by punching a hole in the direction away from the second housing. The edges of the first housing and the second housing are sealed together to form an encapsulation cavity. The first protective sheet is fixed to the inner surface of the first housing and is positioned in the corner area of ​​the first housing. A1≥π[(0.6±0.1)B1] 2 ; Where A1 is the area of ​​the first protective sheet and B1 is the depth of the first cavity.

[0006] As a further improvement to the above technical solution: Optionally, the first protective sheet is a reinforcing film, and the first protective sheet is attached to the inner surface of the first housing.

[0007] Optionally, the first protective sheet has a Young's modulus ≥ 2.0 GPa and a peel strength > 10 N / 25 mm.

[0008] Optionally, a second cavity is formed in the second housing by punching a hole in the direction away from the first housing, and the first cavity and the second cavity are arranged opposite to each other to form the encapsulation cavity.

[0009] Optionally, it further includes a second protective plate, which is fixed to the inner surface of the second housing and positioned in the corner area of ​​the second housing. A²≥π[(0.6±0.1)B²] 2 ; Where A2 is the area of ​​the second protective sheet and B2 is the depth of the second cavity.

[0010] Optionally, the second protective sheet is a reinforcing film, and the second protective sheet is attached to the inner surface of the first housing.

[0011] Optionally, the second protective sheet has a Young's modulus ≥ 2.0 GPa and a peel strength > 10 N / 25 mm.

[0012] Optionally, the first protective sheet may be circular, elliptical, square, or rectangular; and / or, The second protective plate is circular, elliptical, square, or rectangular in shape.

[0013] On the other hand, this utility model embodiment provides a soft-pack battery, including a core and a soft-pack casing as described above, wherein the core is placed in the encapsulation cavity.

[0014] In another aspect, this utility model embodiment provides an electrical device, including the soft-pack battery as described above.

[0015] The present invention provides a soft-pack housing, a soft-pack battery, and an electrical device, which, compared with the prior art, have at least the following advantages: The soft-pack housing includes an aluminum-plastic film and a first protective sheet. The first protective sheet is fixed to the corner area of ​​the first housing and designed with a specific relationship between its area and the depth of the cavity to disperse the stress concentration caused by the expansion of the electrode material, suppress the cracking of the aluminum-plastic film at the corners, and has the advantages of improving battery reliability and cycle life. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of the soft-pack shell provided in one embodiment of the present invention.

[0018] The reference numerals in the accompanying drawings are as follows: 100 - Soft housing, 110 - First protective sheet, 120 - First housing, 130 - Second housing, 140 - Second protective sheet. Detailed Implementation

[0019] To make the technical problems solved, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0020] In the description of this utility model, it should be understood that the terms "longitudinal," "radial," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and 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, and therefore should not be construed as a limitation of this utility model. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0021] 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.

[0022] In existing technologies, the aluminum-plastic film casing of pouch batteries is prone to mechanical stress due to the volume expansion of the electrode material during charge-discharge cycles, leading to cracks in the corner areas. Traditional processes rely on the ductility of the aluminum-plastic film itself and the optimization of the stamping process, but they cannot effectively cope with the stress concentration caused by repeated expansion-contraction cycles, resulting in the risk of electrolyte leakage and performance degradation.

[0023] To address these issues, a structure capable of dispersing stress in corner areas needs to be designed. Considering that aluminum-plastic membrane rupture primarily occurs at corners with abrupt geometric changes, a buffer layer can alleviate localized tension in stress concentration areas. The size of the buffer layer must be related to the depth of shell deformation to ensure effective coverage of high-stress areas.

[0024] Therefore, this application proposes a soft-pack housing 100 structure that combines an aluminum-plastic film with a first protective sheet 110. Please refer to... Figure 1 The aluminum-plastic film is divided into a first housing 120 and a second housing 130. The first housing 120 has a first cavity formed by a perforation, and the edges of the two housings are sealed to form an encapsulation cavity. The first protective sheet 110 is fixed to the corner area of ​​the inner surface of the first housing 120, and its area satisfies a specific relationship with the depth of the cavity.

[0025] The aluminum-plastic film refers to a packaging shell composed of multiple layers of composite materials, specifically a composite laminate structure of nylon, aluminum foil, and polypropylene, used to isolate the external environment and maintain the stability of the internal electrolyte. The first protective sheet 110 refers to a buffer material attached to a specific area inside the shell, specifically a polymer film or elastomer material, used to absorb localized stress. The corner area refers to the geometric transition area formed after the shell is stamped, specifically including the curvature change area at the junction of the cavity edge and the plane, where the material bears the maximum tension during expansion. The relationship between area and depth is used to determine the minimum coverage area of ​​the first protective sheet 110. For example, when the depth of the first cavity is B1, the area A1 of the first protective sheet 110 must satisfy A1≥π[(0.6±0.1)B1]² to ensure that the buffer layer can cover the stress concentration area.

[0026] Specifically, the aluminum-plastic film is stamped to form a concave structure that accommodates the electrode assembly, and the first protective sheet 110 is precisely attached to the corner area before the housing is assembled. During battery charging and discharging, the stress generated by the expansion of the electrode material is dispersed by the first protective sheet 110, preventing delamination or tearing of the aluminum-plastic film composite layer. The area of ​​the first protective sheet 110 is dynamically adjusted according to the depth of the concave cavity; for example, as the depth increases, the area expands quadratically, thereby adapting to the stress distribution requirements of housings of different sizes.

[0027] Compared to existing technologies, traditional solutions do not incorporate directional buffer structures within the casing, relying solely on material ductility to resist stress. This solution addresses this by adding a first protective sheet 110 to specifically alleviate stress concentration in corner areas. Furthermore, the design that correlates area and depth avoids wasting encapsulation space by blindly increasing the thickness of the buffer layer.

[0028] Through the above technical solution, this application can effectively suppress corner cracking of the aluminum-plastic film and reduce the risk of electrolyte leakage. The first protective sheet 110 absorbs and disperses periodic expansion stress, extends the fatigue life of the casing structure under cyclic load, and improves the reliability of high-energy-density soft-pack batteries.

[0029] This application further proposes that the first protective sheet 110 is a reinforcing film, and the first protective sheet 110 is adhered to the inner surface of the first housing 120. The first protective sheet 110 has a Young's modulus ≥ 2.0 GPa and a peel strength > 10 N / 25 mm.

[0030] The film refers to a thin polymer layer material with flexibility and tensile strength. Specifically, it can be made of polyimide, polyester film or modified rubber material, and its thickness can be, for example, 0.05 mm to 0.2 mm. It is used to absorb the mechanical stress generated by electrode expansion in the corner area of ​​the aluminum-plastic film.

[0031] In this context, "adhesion" refers to achieving interface bonding through an adhesive, which can be achieved using acrylic glue, silicone, or hot melt adhesive layers. The peel strength of the adhesive can be controlled within a preset range to ensure a stable stress transfer interface is formed between the first protective sheet 110 and the inner surface of the aluminum-plastic film.

[0032] Specifically, the film is fixed to the corner area of ​​the inner surface of the aluminum-plastic film shell by an adhesive. During battery charge-discharge cycles, the volume expansion of the electrode material forces the corner area of ​​the aluminum-plastic film to deform. At this time, the flexibility of the film can disperse local stress, while the interfacial bonding force of the adhesive can inhibit the delamination of the inner layer material of the aluminum-plastic film. For example, when the aluminum-plastic film bulges outward due to expansion, the film absorbs tensile energy through elastic deformation, while the adhesive layer dissipates stress through shear deformation, thereby reducing the risk of delamination between the aluminum-plastic film composite layers.

[0033] Compared to existing technologies, traditional pouch cells lack a buffer layer with adhesive properties at the corners of the aluminum-plastic film. The stress generated by electrode expansion directly acts on the aluminum-plastic film itself, leading to material fatigue failure. This solution introduces a composite structure of film and adhesive to form an active protective layer in the stress concentration areas of the aluminum-plastic film, dispersing mechanical loads and enhancing interfacial bonding strength.

[0034] Through the above technical solution, this application can effectively suppress delamination and cracking caused by electrode expansion in the corner area of ​​aluminum-plastic film, improve the sealing reliability of soft-pack battery packaging structure, and avoid the risk of electrolyte leakage caused by local stress concentration, thus extending battery cycle life.

[0035] In this embodiment, the first protective sheet 110 is circular, elliptical, square, or rectangular in shape.

[0036] When the first protective sheet 110 is circular, the area of ​​the first protective sheet 110 satisfies A1=π[(0.6±0.1)B1]², where A1 is the area of ​​the first protective sheet and B1 is the depth of the first cavity.

[0037] The circular shape of the first protective sheet 110 means that its outer contour is a closed circular curve. This can be achieved by stamping or die-cutting. This shape can form a continuous and smooth edge transition in the corner area. The area of ​​the first protective sheet 110 satisfies A1=π[(0.6±0.1)B1]², meaning that the coverage area of ​​the circular protective sheet has a quadratic function relationship with the depth B1 of the first cavity. Specifically, the diameter can be controlled between 1.2 and 1.4 times the depth B1 of the first cavity by adjusting the radius of the circle. This proportional relationship is determined based on the stress distribution characteristics of the corner area.

[0038] Specifically, the circular first protective plate 110 is configured to completely cover the stress concentration zone at the corner of the first housing 120, with its circumferential edge equidistant from the housing bend. During battery charging and discharging, the circular structure uniformly disperses the radial stress from the expansion of the electrode material, preventing local stress peaks from accumulating at the housing bend. The curvature of the circular profile causes the edge of the first protective plate 110 to make tangential contact with the deformation direction of the first housing 120, thereby transforming the linear load originally concentrated at the sharp corner into a circumferential load distributed along the circumference.

[0039] Compared with existing technologies, traditional soft-pack housings 100 do not have a first protective sheet 110 of a specific shape, or the use of polygonal protective sheets leads to new stress concentration points at the corners. This solution defines the first protective sheet 110 as circular and establishes a quantitative relationship between its area and the depth of the cavity, so that the edge curvature of the first protective sheet 110 matches the deformation path of the first housing 120, effectively eliminating the stress gradient caused by geometric abrupt changes in the corner area.

[0040] Through the above technical solution, this application can make the stress distribution in the corner area of ​​the first shell 120 more uniform, reduce the probability of delamination or cracking of the aluminum-plastic film during repeated expansion and contraction, thereby improving the cycle stability and packaging reliability of the soft pack battery in the silicon-containing anode system.

[0041] When the first protective plate 110 is elliptical in shape, then A1≥π[(0.6±0.1)B1] 2 Where A1 is the area of ​​the first protective sheet 110 and B1 is the depth of the first cavity.

[0042] Here, the ellipse refers to an asymmetric closed curve shape with a major axis and a minor axis. It can be manufactured using stamping or laser cutting processes. Its major axis can be arranged along the principal stress distribution direction at the corner of the shell to optimize stress dispersion. The area formula is A1≥π[(0.6±0.1)B1] 2 The minimum coverage area of ​​the first protective plate 110 is defined, which can be achieved by adjusting the ratio of the major axis to the minor axis of the ellipse. This formula establishes a relationship between the protected area and the cavity depth, ensuring that the first housing 120 structure at different depths can be effectively protected.

[0043] Specifically, the major axis of the elliptical first protective sheet 110 can extend along the direction of maximum principal stress at the corner of the first housing 120, and its geometric characteristics allow for a larger effective coverage area within a limited space. When the depth of the first cavity changes, the protected area range can be adaptively adjusted by maintaining the square ratio of area to depth. The continuous curvature of the elliptical edge helps to eliminate the sharp corner stress concentration points of traditional polygonal protective sheets, forming a more uniform stress distribution.

[0044] Compared to existing technologies, traditional circular protective plates suffer from a single coverage direction in corner areas, while elliptical structures, with their axially adjustable characteristics, can better match the multi-directional stress distribution during shell deformation. Compared to the risk of stress concentration at sharp corners present in polygonal protective plates, the smooth contour of an elliptical shape can effectively reduce local stress peaks and prevent the protective plate itself from becoming a new source of stress concentration.

[0045] Through the above technical solution, this application can provide directional protection for the multi-directional stress distribution characteristics of the 100-degree corner area of ​​the soft-pack battery. While maintaining the effective protection area, it eliminates the risk of secondary stress concentration in traditional protection structures, significantly reduces the probability of delamination and cracking of the aluminum-plastic film under cyclic expansion stress, and thus extends the cycle life of high-energy-density soft-pack batteries.

[0046] When the shape of the first protective plate 110 is square, it satisfies A1≥π[(0.6±0.1)B1]², where A1 is the area of ​​the first protective plate 110 and B1 is the depth of the first cavity.

[0047] The first protective sheet refers to the stress-resistant material layer covering the inner surface of the aluminum-plastic film, which can be made of polyimide tape or modified polypropylene film, and is used to absorb and disperse the mechanical stress at the corners of the shell. The square shape refers to a planar geometric structure with four equal sides and right angles, which can be formed by laser cutting or die-cutting processes. Its symmetry helps to evenly disperse the stress concentration in the corner area. The relationship between area and depth, A1≥π[(0.6±0.1)B1]², refers to the matching relationship between the coverage area of ​​the first protective sheet 110 and the deformation of the first concave cavity. It is determined through numerical simulation and fatigue test to ensure that the stress concentration area can still be effectively covered under the maximum expansion deformation.

[0048] Specifically, the square first protective sheet 110 is precisely attached to the corner area of ​​the stamped first housing 120, with its edges and corners perfectly aligned with the bent portion of the first housing 120. When the electrode material expands, the tensile stress generated at the corner of the first housing 120 is dispersed to a larger contact area through the rigid support of the first protective sheet 110. The four-sided symmetry of the square structure ensures that the stress is uniformly transmitted along the bending line of the first housing 120, preventing single-point stress from exceeding the yield strength of the aluminum-plastic film. The area of ​​the first protective sheet 110 is determined proportionally to the depth of the first cavity. For example, when the depth of the first cavity is 3 mm, the side length of the first protective sheet 110 can be set to the range of 3.2 mm to 4.2 mm to ensure coverage of the stress area generated by expansion deformation.

[0049] Compared to existing technologies, traditional solutions often employ circular protective sheets 110 or randomly shaped reinforcing layers, failing to effectively match the right-angle geometry of the housing corners. The right-angled side of the square first protective sheet 110 forms continuous support with the bending line of the first housing 120, reducing the edge gap area by approximately 27% compared to the circular first protective sheet 110, significantly improving stress transfer efficiency. Experimental data shows that adopting this solution increases the fatigue life at the aluminum-plastic film corners by more than 2.3 times without increasing the encapsulation thickness.

[0050] Through the above technical solution, this application effectively suppresses material delamination at the corners of the casing during charge-discharge cycles, reducing the electrolyte leakage rate to below 18% of the original level. The geometric adaptability of the square first protective sheet 110 enables the first casing 120 to maintain structural integrity when subjected to cyclic expansion stress, providing a reliable packaging solution for high-energy-density pouch batteries.

[0051] When the first protective sheet 110 is rectangular, its area satisfies A1≥π[(0.6±0.1)B1]², where A1 is the area of ​​the first protective sheet 110 and B1 is the depth of the first cavity.

[0052] The first protective sheet 110 is rectangular, meaning it has four right angles and opposite sides of equal length. It can be manufactured using stamping or laser cutting processes. This shape matches the geometric features of the corner area of ​​the aluminum-plastic film. The area A1 is calculated using a mathematical model based on the cavity depth B1, which can be achieved by adjusting the length and width ratio of the rectangle. This formula limits the minimum coverage area of ​​the first protective sheet to ensure effective stress dispersion.

[0053] Specifically, when the corner area of ​​the aluminum-plastic film shell is subjected to cyclic expansion stress, the longer side of the rectangle can be arranged along the corner extension direction, while the shorter side is perpendicular to the stress transmission path. By increasing the contact area, the localized concentrated stress is evenly distributed to a larger area. The range of coefficients in the formula is determined through experimental verification, ensuring that the area of ​​the protective sheet always meets the coverage requirements under different cavity depths, and avoiding stress buffer failure due to insufficient area.

[0054] Compared to existing technologies, traditional soft-pack housings 100 do not have protective plates of a specific shape in the corner areas, while conventional circular or elliptical protective plates have blind spots. The rectangular protective plate, through its right-angle structure, forms a geometric complement to the corners of the housing, effectively eliminating edge gaps. Its adjustable length and width can adapt to concave structures of different sizes, significantly improving the accuracy and reliability of stress buffering.

[0055] Through the above technical solution, this application can effectively suppress the risk of delamination and cracking in the corner area of ​​the aluminum-plastic film under cyclic expansion stress. The rectangular planar structure reduces the mechanical load per unit area by maximizing the coverage area. The area calculation formula ensures that the size of the protective sheet and the depth of the cavity form a reasonable ratio, thereby extending the cycle life of the soft-pack battery and improving the packaging reliability.

[0056] Please see Figure 1 This application further proposes that a second cavity is formed in the second housing 130 in the direction away from the first housing 120, and the first cavity and the second cavity are arranged opposite to each other to form an encapsulation cavity.

[0057] The second cavity refers to a recessed structure formed on the inner surface of the second housing 130, which can be achieved through a stamping process. Its depth matches that of the first cavity, and together with the first cavity, they enclose a space to accommodate the core. "Relative arrangement" means that the first and second cavities correspond to each other in spatial position, with their edges aligned and shapes complementary, resulting in a symmetrical geometric distribution of the encapsulation cavities.

[0058] Specifically, the introduction of the second cavity allows the depth of the encapsulation cavity to be shared by the first and second cavities, and the edges of the first and second cavities are sealed together to form a complete encapsulation structure. During battery charging and discharging, the stress generated by the expansion of the core is dispersed to the sidewall areas of the first and second cavities, avoiding excessive stress concentration at the corners of a single casing.

[0059] The soft-pack housing 100 uses only a single-sided concave cavity structure, and the encapsulation cavity depth depends entirely on the first concave cavity, resulting in stress concentration at the corner area of ​​the housing. This solution uses a symmetrical design with two concave cavities to distribute the stress evenly along both sides of the housing, reducing local stress peaks.

[0060] Through the above technical solution, this application effectively alleviates the stress concentration phenomenon in the corner area of ​​aluminum-plastic film, suppresses material delamination or cracking caused by repeated expansion and contraction, thereby reducing the risk of electrolyte leakage and improving battery cycle life.

[0061] Please see Figure 1 This application further proposes a second protective sheet 140, which is fixed to the inner surface of the second housing 130 and positioned in the corner area of ​​the second housing 130, and A2≥π[(0.6±0.1)B2] 2 Where A2 is the area of ​​the second protective sheet 140, and B2 is the depth of the second cavity.

[0062] The second protective plate 140 is distributed on the inner surface and corner areas of the second housing 130, and can be fixed by adhesive or hot pressing to disperse stress in the corner areas of the housing. The corner area refers to the transition area where the edge of the cavity formed after the housing is stamped connects to the housing plane; specifically, it can be a geometric transition area formed by the intersection of the cavity depth direction and the housing plane. This area is prone to stress concentration due to the abrupt change in geometry. The relationship between area and cavity depth means that the coverage area of ​​the second protective plate 140 must satisfy a specific formula, which can be achieved by using a circular, elliptical, or regular polygonal shape to ensure that the second protective plate 140 can effectively cover the stress concentration area.

[0063] Specifically, when the second housing 130 forms the second cavity and together with the first cavity to form an encapsulation cavity, the inner surface and corner areas of the second housing 130 also bear the mechanical stress generated by the expansion of the electrode material. By setting multiple protective sheets on the inner surfaces and corner areas of the first housing 120 and the second housing 130 respectively, the stress concentration areas are covered by the protective sheets. The area of ​​the protective sheet is calculated and determined according to the depth of the corresponding cavity. For example, when the cavity depth is a specific value, the area of ​​the protective sheet must meet a minimum threshold, thereby continuously dispersing local stress during repeated expansion-contraction cycles and preventing the aluminum-plastic film from delaminating or cracking.

[0064] Compared with existing technologies, traditional soft-shell housings 100 only have protective plates within a single housing, and the distribution of protective plates is not optimized for the double-cavity structure. This solution, by arranging multiple protective plates on the inner surface and corner areas of the double-shell structure, and dynamically adjusting the area of ​​the protective plates according to the cavity depth, can more comprehensively cover stress concentration areas and significantly reduce the risk of mechanical damage caused by abrupt changes in geometry.

[0065] Through the above technical solution, this application effectively alleviates the problem of aluminum-plastic film delamination caused by electrode material expansion during charge-discharge cycles in dual-shell structures. It is especially suitable for soft-pack batteries using high-energy-density negative electrode materials, extending the cycle life of the battery and improving the packaging reliability.

[0066] This application further proposes that the second protective sheet 140 is a reinforcing film, which is adhered to the inner surface of the shell. The second protective sheet 140 has a Young's modulus ≥ 2.0 GPa and a peel strength > 10 N / 25 mm.

[0067] The film refers to a thin polymer layer material with flexibility and tensile strength. Specifically, it can be made of polyimide, polyester film or modified rubber material, and its thickness can be, for example, 0.05 mm to 0.2 mm. It is used to absorb the mechanical stress generated by electrode expansion in the corner area of ​​the aluminum-plastic film.

[0068] Adhesion refers to the bonding of interfaces through adhesives, such as acrylic glue, silicone, or hot melt adhesive layers. The peel strength of the adhesive can be controlled within a preset range to ensure a stable stress transfer interface is formed between the second protective sheet 140 and the inner surface of the aluminum-plastic film.

[0069] Specifically, the film is fixed to the corner area of ​​the inner surface of the aluminum-plastic film shell by an adhesive. During battery charge-discharge cycles, the volume expansion of the electrode material forces the corner area of ​​the aluminum-plastic film to deform. At this time, the flexibility of the film can disperse local stress, while the interfacial bonding force of the adhesive can inhibit the delamination of the inner layer material of the aluminum-plastic film. For example, when the aluminum-plastic film bulges outward due to expansion, the film absorbs tensile energy through elastic deformation, while the adhesive layer dissipates stress through shear deformation, thereby reducing the risk of delamination between the aluminum-plastic film composite layers.

[0070] Compared to existing technologies, traditional pouch cells lack a buffer layer with adhesive properties at the corners of the aluminum-plastic film. The stress generated by electrode expansion directly acts on the aluminum-plastic film itself, leading to material fatigue failure. This solution introduces a composite structure of film and adhesive to form an active protective layer in the stress concentration areas of the aluminum-plastic film, dispersing mechanical loads and enhancing interfacial bonding strength.

[0071] Through the above technical solution, this application can effectively suppress delamination and cracking caused by electrode expansion in the corner area of ​​aluminum-plastic film, improve the sealing reliability of soft-pack battery packaging structure, and avoid the risk of electrolyte leakage caused by local stress concentration, thus extending battery cycle life.

[0072] In this embodiment, the second protective sheet 140 is circular, elliptical, square, or rectangular in shape.

[0073] When the second protective plate 140 is circular, its area satisfies A2=π[(0.6±0.1)B2]², where A2 is the area of ​​the second protective plate 140 and B2 is the depth of the second cavity.

[0074] The second protective plate 140 is circular in shape, meaning its outer contour forms a closed circular curve. This can be achieved through stamping or die-cutting processes, and this shape allows for a smooth, continuous edge transition in the corner area. The area of ​​the second protective plate 140 satisfies A²=π[(0.6±0.1)B²]², meaning the coverage area of ​​the circular second protective plate has a quadratic function relationship with the depth of the second cavity. Specifically, the diameter can be controlled between 1.2 and 1.4 times the depth of the second cavity by adjusting the radius of the circle. This proportional relationship is determined based on the stress distribution characteristics of the corner area.

[0075] Specifically, the circular second protective plate 140 is configured to completely cover the stress concentration zone at the corner of the second housing 130, with its circumferential edge equidistant from the bend of the second housing 130. During battery charging and discharging, the circular structure uniformly disperses the radial stress from the expansion of the electrode material, preventing local stress peaks from accumulating at the housing bend. The curvature of the circular profile causes the edge of the second protective plate 140 to make tangential contact with the deformation direction of the second housing 130, thereby transforming the linear load originally concentrated at the sharp corner into a circumferential load distributed along the circumference.

[0076] Compared with existing technologies, traditional soft-pack housings 100 do not have a second protective sheet 140 of a specific shape, or the use of polygonal protective sheets leads to new stress concentration points at the corners. This solution defines the second protective sheet 140 as circular and establishes a quantitative relationship between its area and the depth of the second cavity, so that the edge curvature of the second protective sheet 140 matches the deformation path of the housing, effectively eliminating the stress gradient caused by geometric abrupt changes in the corner area.

[0077] Through the above technical solution, this application can make the stress distribution in the corner area of ​​the shell more uniform, reduce the probability of delamination or cracking of the aluminum-plastic film during repeated expansion and contraction, thereby improving the cycle stability and packaging reliability of the soft pack battery in the silicon-containing anode system.

[0078] When the second protective plate 140 is elliptical, then A2≥π[(0.6±0.1)B2] 2 Where A2 is the area of ​​the second protective sheet 140, and B2 is the depth of the second cavity.

[0079] The ellipse shape refers to an asymmetric closed curve shape with a major axis and a minor axis. It can be manufactured using stamping or laser cutting processes. Its major axis can be arranged along the principal stress distribution direction of the 130° corner of the second shell to optimize stress dispersion. The area formula is A² ≥ π[(0.6 ± 0.1)B²]. 2 The minimum coverage area of ​​the second protective plate 140 is defined, which can be achieved by adjusting the ratio of the major axis to the minor axis of the ellipse. This formula establishes a relationship between the protected area and the cavity depth, ensuring that the second housing 130 structure at different depths can be effectively protected.

[0080] Specifically, the major axis of the elliptical second protective plate 140 can extend along the direction of maximum principal stress at the corner of the second housing 130, and its geometric characteristics allow for a larger effective coverage area within a limited space. When the depth of the second cavity changes, the protected area range can be adaptively adjusted by maintaining the square ratio of area to depth. The continuous curvature of the elliptical edge helps to eliminate the sharp corner stress concentration points of traditional polygonal protective plates, forming a more uniform stress distribution.

[0081] Compared to existing technologies, traditional circular protective plates suffer from a single coverage direction in corner areas, while the elliptical structure, with its axially adjustable characteristics, can better match the multi-directional stress distribution during the deformation of the second shell 130°. Compared to the risk of stress concentration at sharp corners present in polygonal protective plates, the smooth contour of the elliptical shape can effectively reduce local stress peaks and prevent the protective plate itself from becoming a new source of stress concentration.

[0082] Through the above technical solution, this application can provide directional protection for the multi-directional stress distribution characteristics of the 100-degree corner area of ​​the soft-pack battery. While maintaining the effective protection area, it eliminates the risk of secondary stress concentration in traditional protection structures, significantly reduces the probability of delamination and cracking of the aluminum-plastic film under cyclic expansion stress, and thus extends the cycle life of high-energy-density soft-pack batteries.

[0083] When the second protective plate 140 is square, then A2≥π[(0.6±0.1)B2] is satisfied. 2 Where A2 is the area of ​​the second protective sheet 140 and B2 is the depth of the second cavity.

[0084] The second protective layer 140 refers to the stress-resistant material layer covering the inner surface of the aluminum-plastic film. Specifically, it can be made of polyimide tape or modified polypropylene film, used to absorb and disperse the mechanical stress at the corners of the shell. The square shape refers to a planar geometric structure with four equal sides and right angles, which can be formed by laser cutting or die-cutting processes. Its symmetry helps to evenly disperse stress concentration in the corner areas. The relationship between area and depth is A²≥π[(0.6±0.1)B²]. 2 This refers to the matching relationship between the coverage area of ​​the second protective plate 140 and the deformation of the second concave cavity. Specifically, it is determined through numerical simulation and fatigue test to ensure that the stress concentration area can still be effectively covered under the maximum expansion deformation.

[0085] Specifically, the square second protective sheet 140 is precisely attached to the corner area of ​​the stamped second housing 130, with its edges perfectly aligned with the bent portion of the second housing 130. When the electrode material expands, the tensile stress generated at the corner of the second housing 130 is dispersed to a larger contact area through the rigid support of the second protective sheet 140. The four-sided symmetry of the square structure ensures that stress is uniformly transmitted along the bending line of the second housing 130, preventing single-point stress from exceeding the yield strength of the aluminum-plastic film. The area of ​​the second protective sheet 140 is determined proportionally to the depth of the second cavity. For example, when the depth of the second cavity is 3 mm, the side length of the protective sheet 110 can be set to the range of 3.2 mm to 4.2 mm to ensure coverage of the stress area generated by expansion deformation.

[0086] Compared to existing technologies, traditional solutions often employ circular protective sheets or randomly shaped reinforcing layers, failing to effectively match the right-angle geometry of the housing corners. The right-angled side of the square second protective sheet 140 forms continuous support with the bending line of the second housing 130, reducing edge gaps by approximately 27% compared to circular protective sheets and significantly improving stress transfer efficiency. Experimental data shows that adopting this solution increases fatigue life at the aluminum-plastic film corners by more than 2.3 times without increasing the encapsulation thickness.

[0087] Through the above technical solution, this application effectively suppresses material delamination at the corners of the casing during charge-discharge cycles, reducing the electrolyte leakage rate to below 18% of the original level. The geometric adaptability of the square second protective sheet 140 enables the second casing 130 to maintain structural integrity when subjected to cyclic expansion stress, providing a reliable packaging solution for high-energy-density pouch batteries.

[0088] When the second protective plate 140 is rectangular, its area satisfies A²≥π[(0.6±0.1)B²]. 2 Where A2 is the area of ​​the second protective sheet 140 and B2 is the depth of the second cavity.

[0089] The second protective sheet 140 is rectangular, meaning it has four right angles and opposite sides of equal length. It can be manufactured using stamping or laser cutting processes. This shape matches the geometric features of the corner area of ​​the aluminum-plastic film. The area A2 is calculated using a mathematical model based on the cavity depth B2, which can be achieved by adjusting the length and width ratio of the rectangle. This formula limits the minimum coverage area of ​​the second protective sheet 140 to ensure effective stress dispersion.

[0090] Specifically, when the corner area of ​​the aluminum-plastic film shell is subjected to cyclic expansion stress, the longer side of the rectangle can be arranged along the corner extension direction, while the shorter side is perpendicular to the stress transmission path. By increasing the contact area, the localized concentrated stress is evenly distributed to a larger area. The range of coefficients in the formula is determined through experimental verification, ensuring that the area of ​​the second protective sheet 140 always meets the coverage requirements under different second cavity depths, avoiding stress buffer failure due to insufficient area.

[0091] Compared to existing technologies, traditional soft-pack housings 100 do not have protective plates of a specific shape in the corner areas, while conventional circular or elliptical protective plates have blind spots. The rectangular second protective plate 140 forms a geometric complement to the corner of the second housing 130 through a right-angle structure, effectively eliminating edge gaps. Its adjustable length and width can be adapted to concave structures of different sizes, significantly improving the accuracy and reliability of stress buffering.

[0092] Through the above technical solution, this application can effectively suppress the risk of delamination and cracking in the corner area of ​​the aluminum-plastic film under cyclic expansion stress. The rectangular planar structure reduces the mechanical load per unit area by maximizing the coverage area. The area calculation formula ensures that the size of the second protective sheet 140 and the depth of the second cavity are in a reasonable ratio, thereby extending the cycle life of the soft-pack battery and improving the packaging reliability.

[0093] This application further proposes a pouch battery, including a core and a pouch casing 100, with the core placed in the encapsulation cavity.

[0094] The soft housing 100 refers to the encapsulation structure made of aluminum-plastic film. The aluminum-plastic film includes a first housing 120 and a second housing 130 formed by stamping. The edges of the two are sealed to form an encapsulation cavity. Specifically, it can be made of nylon, aluminum foil and polypropylene composite material. A protective sheet 110 is fixed in the corner area of ​​its inner surface to deal with local stress concentration.

[0095] The core being placed in the encapsulation cavity means that the electrochemical unit composed of positive and negative electrode plates and a separator is housed in the concave cavity structure of the shell. Specifically, it can be achieved by winding or stacking processes. The mechanical load generated by its expansion is distributed to the shell through the protective sheet 110.

[0096] Specifically, the soft-pack housing 100 is formed by stamping an aluminum-plastic film to create a cavity structure, and the core is encapsulated within the cavity sealed by the first housing 120 and the second housing 130. During charging and discharging, the core exerts periodic stress on the corner areas of the housing due to material expansion. The protective sheet 110, by covering the inner surface of the corner areas, disperses the load of the stress concentration area to a larger area of ​​the aluminum-plastic film substrate, thereby reducing the risk of delamination or cracking. In addition, the sealed connection design of the encapsulation cavity ensures the isolation between the electrolyte and the core, while allowing the housing to absorb some of the expansion energy through the deformation buffer of the protective sheet 110.

[0097] In some specific embodiments, the protective sheet 110 can be circular, elliptical or square, for example, it can be attached to the corner of the shell using polyimide tape with a thickness of 0.1 mm; the core can contain silicon-carbon anode material, for example, it can be a spiral structure of silicon-oxygen anode and high-nickel ternary cathode.

[0098] Compared to existing technologies, traditional pouch battery casings lack protective structures in corner areas, making the aluminum-plastic film prone to delamination and cracking under repeated expansion stress. This solution introduces a protective sheet 110, which disperses the stress originally concentrated at the corner through a larger protective material. At the same time, the bonding interface between the protective sheet 110 and the aluminum-plastic film absorbs deformation energy, thereby significantly reducing the probability of corner breakage.

[0099] Through the above technical solution, this application effectively alleviates the problem of aluminum-plastic film corner breakage caused by negative electrode expansion in high energy density batteries, extends battery cycle life, and maintains the sealing integrity of the packaging structure. It is suitable for the manufacture of soft-pack batteries with silicon-containing negative electrode systems.

[0100] This application further proposes an electrical device including a pouch battery, the pouch battery including a core and a pouch casing 100, the core being placed in an encapsulation cavity.

[0101] Among them, electrical devices refer to equipment that converts electrical energy into other forms of energy or uses electrical energy to drive devices. Specifically, they can be mobile terminals, electric vehicles, or energy storage devices. By integrating soft-pack batteries as energy supply units, the equipment's requirements for high energy density and reliability can be met.

[0102] Among them, the soft-pack battery refers to a secondary battery with an aluminum-plastic film encapsulation structure. Specifically, it can be achieved by setting a protective sheet 110 in the corner area of ​​the casing. The protective sheet 110 disperses the mechanical stress at the corner of the casing and reduces the risk of the aluminum-plastic film cracking due to the expansion of the electrode material.

[0103] Specifically, the core of the pouch battery is encapsulated within a cavity made of an aluminum-plastic film. The edges of the first shell 120 and the second shell 130 of the aluminum-plastic film are sealed to form a closed space. A protective sheet 110 is fixed at the corner of the shell, covering the inner surface of the corner. When the core expands in volume during charging and discharging, the expansion force acts on the corner area of ​​the shell. The protective sheet 110, through the matching relationship between its area and the depth of the cavity, disperses the localized stress to a larger area, preventing the aluminum-plastic film from delaminating or cracking. By using this pouch battery, the device can maintain the integrity of the encapsulation in high-energy-density scenarios, thereby ensuring the continuous and stable operation of the equipment.

[0104] Compared to existing technologies, the soft-pack batteries used in current electrical devices lack protective structures at the corners of the casing. During battery cycling, the corner areas of the aluminum-plastic film are prone to cracking due to stress concentration, leading to risks of leakage or performance degradation in the electrical devices. This application optimizes the casing structure by introducing a protective sheet 110, resulting in a more uniform stress distribution at the corner areas of the aluminum-plastic film and significantly reducing the probability of encapsulation failure.

[0105] Through the above technical solutions, this application can improve the safety of electrical devices in long-term charge and discharge cycles, reduce equipment failures caused by the rupture of soft-pack battery packaging, and extend the service life of batteries in high energy density systems.

[0106] The above-described embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model, and should all be included within the protection scope of this utility model.

Claims

1. A soft pouch housing characterized by, The enclosure includes an aluminum-plastic film and a first protective sheet (110). The aluminum-plastic film includes a first housing (120) and a second housing (130). A first cavity is formed in the first housing (120) by punching a hole in the direction away from the second housing (130). The edges of the first housing (120) and the second housing (130) are sealed together so that the first housing (120) and the second housing (130) form an encapsulation cavity. The first protective sheet (110) is fixed to the inner surface of the first housing (120) and is placed in the corner area of ​​the first housing (120). A1≥ π[(0.6 ± 0.1) B1] 2 ; Where A1 is the area of ​​the first protective sheet (110) and B1 is the depth of the first cavity.

2. The soft pouch housing of claim 1, wherein, The first protective sheet (110) is a reinforcing film, and the first protective sheet (110) is attached to the inner surface of the first housing (120).

3. The soft pouch housing of claim 2, wherein, The first protective sheet (110) has a Young's modulus ≥ 2.0 GPa and a peel strength > 10 N / 25 mm.

4. The soft pouch according to any one of claims 1 to 3, characterized in that, The second housing (130) has a second cavity formed by punching a hole in the direction away from the first housing (120), and the first cavity and the second cavity are arranged opposite to each other to form the encapsulation cavity.

5. The soft pouch housing of claim 4, wherein, It also includes a second protective plate (140), which is fixed to the inner surface of the second housing (130). The second protective plate (140) is placed in the corner area of ​​the second housing (130), and A2≥ π[(0.6 ± 0.1)B2] 2 ; Where A2 is the area of ​​the second protective sheet (140) and B2 is the depth of the second cavity.

6. The soft pouch of claim 5, wherein, The second protective sheet (140) is a reinforcing film, and the second protective sheet (140) is attached to the inner surface of the first housing (120).

7. The soft pouch of claim 6, wherein, The second protective sheet (140) has a Young's modulus ≥2.0GPa and a peel strength >10N / 25mm.

8. The soft pouch of claim 5, wherein, The first protective plate (110) is circular, elliptical, square, or rectangular in shape; and / or, The second protective piece (140) is circular, elliptical, square or rectangular in shape.

9. A pouch battery, characterized by, It includes a core and a soft-pack housing (100) as described in any one of claims 1 to 8, wherein the core is placed in the encapsulation cavity.

10. An electrical device, characterized by Includes the pouch cell as described in claim 9.

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