Electrochemical device

Abstract

The utility model discloses an electrochemical device, this electrochemical device includes aluminium plastic film and electrode assembly, aluminium plastic film includes main part, and electrode assembly sets up in the main part, and the outer surface of electrode assembly is provided with bonding member, and the inner wall interval structure of main part has a plurality of grooves, and bonding member is bonded with a plurality of grooves, and the sum of the projection area of a plurality of grooves on the surface of electrode assembly is greater than the projection area on the surface of electrode assembly. Through the inner wall interval structure of aluminium plastic film main part a plurality of grooves, and make a plurality of grooves on the surface of electrode assembly projection area is greater than the area of bonding member, can effectively avoid the problem that hot melt adhesive bonding member produces bubble in the roll core baking process in the prior art, to this promotion bonding member and the effective bonding area and bonding strength between aluminium plastic film inner wall.

Description

Technical Field

[0001] This application relates to the field of electrochemical energy storage technology, and in particular to an electrochemical device. Background Technology

[0002] Pouch batteries have advantages such as high energy density, flexible shape, and light weight, and are widely used in portable electronic products such as smartphones, tablets, and laptops. In actual use, these devices often face mechanical stresses such as accidental drops and impacts, which places strict requirements on the structural integrity and safety performance of the batteries.

[0003] To address battery drop failure, related technologies typically involve attaching adhesives to the surface of the electrode assembly. This enhances the bond strength between the electrode assembly surface and the aluminum-plastic film, thereby improving the overall impact resistance of the battery. The adhesives effectively transfer and disperse stress when the battery is subjected to external impact, preventing relative displacement or separation between the electrode assembly and the inner wall of the aluminum-plastic film. This avoids safety hazards such as damage to the internal structure of the electrochemical device and electrolyte leakage.

[0004] However, the relevant technology has obvious drawbacks. During the battery manufacturing process, the electrochemical device needs to undergo a baking process to remove moisture and solvents. During this process, the adhesive is activated, and air bubbles are easily formed between the adhesive and the inner wall of the aluminum-plastic film. The presence of air bubbles reduces the effective bonding area and bonding strength between the adhesive and the inner wall of the aluminum-plastic film. Utility Model Content

[0005] The main objective of this application is to provide an electrochemical device designed to improve the bonding stability between the adhesive and the inner wall of the aluminum-plastic film.

[0006] To achieve the above objectives, this application proposes an electrochemical device comprising an aluminum-plastic film and an electrode assembly. The aluminum-plastic film includes a main body, and the electrode assembly is disposed within the main body. An adhesive is provided on the outer surface of the electrode assembly. The inner wall of the main body is provided with a plurality of grooves at intervals. The adhesive is bonded to the plurality of grooves, and the sum of the projected areas of the plurality of grooves on the surface of the electrode assembly is greater than the projected area of ​​the adhesive on the surface of the electrode assembly.

[0007] In some embodiments, the plurality of grooves form a slot area on the inner wall of the main body, the edge of the slot area extending 0.5 mm to 4 mm beyond the edge of the adhesive.

[0008] In some embodiments, the spacing between adjacent grooves is D, the width of the groove is W, and the following relationship is satisfied:

[0009] D = W*(2~4);

[0010] W = 0.1 to 1.

[0011] In some embodiments, the main body includes a nylon layer, an aluminum foil layer, and a PP layer stacked sequentially. The aluminum foil layer is bonded to the nylon layer and the PP layer via an adhesive layer. A plurality of grooves are formed on the surface of the PP layer facing away from the aluminum foil layer. The thickness of the PP layer is H1, and the depth of the grooves is H, satisfying the following relationship:

[0012] H≤0.5*H1.

[0013] In some embodiments, the depth of the groove is 5 μm to 40 μm.

[0014] In some embodiments, the groove is U-shaped; or, the groove is V-shaped.

[0015] In some embodiments, a plurality of the grooves are distributed at intervals along the length direction of the main body and extend along the width direction of the main body.

[0016] In some embodiments, a plurality of the grooves are distributed at intervals along the width direction of the main body and extend along the length direction of the main body.

[0017] In some embodiments, the groove is a first groove and a second groove, the first groove extends along the length direction of the main body, the second groove extends along the width direction of the main body, and the first groove and the second groove intersect.

[0018] In some embodiments, the intersection angle between the first groove and the second groove is 30° to 160°.

[0019] This application's technical solution effectively avoids the problem of air bubbles forming in the adhesive during the core baking process by constructing multiple grooves at intervals on the inner wall of the aluminum-plastic film body, and ensuring that the projected area of ​​these grooves on the electrode assembly surface is larger than the area of ​​the adhesive. Specifically, when the adhesive is activated during high-temperature baking, the generated gas can be discharged promptly through the grooves, providing ample channel space for gas migration and preventing gas from accumulating and forming bubbles between the adhesive and the inner wall of the aluminum-plastic film. By eliminating bubble defects, not only is the appearance quality of the electrochemical device improved and the overall thickness of the device reduced, but the effective bonding area and bonding strength between the adhesive and the inner wall of the aluminum-plastic film are also increased, ensuring that the adhesive can fully exert its stress transmission and dispersion functions, thereby effectively preventing the electrochemical device from failing under mechanical stress such as drop impacts. Attached Figure Description

[0020] Figure 1This is a schematic diagram of the cross-sectional structure of the aluminum-plastic film body along its thickness direction in one embodiment of the electrochemical device of this application;

[0021] Figure 2 This is a schematic diagram of the structure of the aluminum-plastic film body in one embodiment of the electrochemical device of this application;

[0022] Figure 3 This is a schematic diagram of the structure of the aluminum-plastic film body in another embodiment of the electrochemical device of this application;

[0023] Figure 4 This is a schematic diagram of the structure of the aluminum-plastic film body in another embodiment of the electrochemical device of this application. Attached image description:

[0025] 100a, Main body; 101, Nylon layer; 102, Aluminum foil layer; 103, PP layer; 104, Adhesive layer; F, Width direction; E, Height direction;

[0026] 120. Groove; 121. First groove; 122. Second groove;

[0027] 201. Adhesive components. Detailed Implementation

[0028] The solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments in this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0029] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0030] It should also be noted that when a component is described as "fixed to" or "set on" another component, it can be directly on the other component or there may be an intervening component present. When a component is described as "connected to" another component, it can be directly connected to the other component or there may be an intervening component present.

[0031] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.

[0032] To address battery drop failure, adhesives are often attached to the surface of the electrode assembly to enhance the bond strength between the electrode assembly and the aluminum-plastic film, thereby improving the overall impact resistance of the battery. However, during the heating and activation process of the adhesive, numerous air bubbles are generated between the electrode assembly and the aluminum-plastic film, affecting the bonding area and causing bulges on the aluminum-plastic film's appearance, thus impacting its quality. Therefore, this invention proposes an electrochemical device that reduces air bubbles and increases the bonding area. By constructing multiple grooves at intervals on the inner wall of the aluminum-plastic film body, and ensuring that the projected area of ​​these grooves on the electrode assembly surface is larger than the area of ​​the adhesive, this effectively solves the problem of air bubble generation in hot melt adhesives during the core baking process in existing technologies.

[0033] For details, please refer to Figure 1 As shown, Figure 1 This is a schematic cross-sectional view of the aluminum-plastic film main body along its thickness direction in one embodiment of the electrochemical device of this application. The embodiment of this application proposes an electrochemical device including an aluminum-plastic film and an electrode assembly. The aluminum-plastic film includes a main body 100a, and the electrode assembly is disposed in the main body 100a. An adhesive 201 is disposed on the outer surface of the electrode assembly. The inner wall of the main body 100a is constructed with a plurality of grooves 120 at intervals. The adhesive 201 is bonded to the plurality of grooves 120. The sum of the projected areas of the plurality of grooves 120 on the surface of the electrode assembly is greater than the projected area of ​​the adhesive 201 on the surface of the electrode assembly.

[0034] The electrochemical device of this application includes any device in which an electrochemical reaction occurs to convert chemical energy into electrical energy, and specific, non-limiting examples include all kinds of primary batteries, secondary batteries, fuel cells, solar cells, or capacitors. In particular, the electrochemical device is preferably a lithium secondary battery, including lithium metal secondary batteries, lithium-ion secondary batteries, lithium polymer secondary batteries, or lithium-ion polymer secondary batteries.

[0035] The electrode assembly mainly includes electrode sheets and a separator layered and wound around the electrode sheets. Specifically, it includes a positive electrode sheet, a negative electrode sheet, and a separator layer disposed between the positive and negative electrode sheets. The positive electrode sheet typically includes a positive current collector and a positive active material layer coated on the current collector, while the negative electrode sheet includes a negative current collector and a negative active material layer coated on the current collector.

[0036] In this embodiment, the aluminum-plastic film is mainly used to encapsulate the electrode assembly, serving a sealing and protective function. Its material can be a composite material structure consisting of a nylon layer 101, an aluminum foil layer 102, and a PP layer 103 stacked sequentially, or other flexible packaging materials with good barrier properties can be used. Grooves 120 are provided on the inner surface of the PP layer 103. The number of grooves 120 can be multiple, such as 2, 5, 10, or more, and the specific number of grooves 120 can be adjusted according to the distribution area and area of ​​the adhesive component 201. Regardless of the number of grooves 120, their projected area on the electrode assembly surface is larger than the area of ​​the adhesive component 201, providing sufficient exhaust channels for gases generated during heating. The adhesive component 201 can be hot melt adhesive, double-sided tape, or other materials with adhesive functions, preferably a heat-activated hot melt adhesive. The grooves 120 can be formed by laser etching, machining, molding, or other methods.

[0037] In fabricating the electrochemical device, multiple grooves 120 are first machined on the inner wall of the aluminum-plastic film used to cover the electrode assembly. The prepared positive electrode sheet, separator, and negative electrode sheet are stacked sequentially in the order of positive electrode, separator, negative electrode, separator, and then a winding or stacking process is performed to obtain the electrode assembly. An adhesive 201 is placed on the outer surface of the electrode assembly. It should be noted that the adhesive 201 can cover a portion of the outer surface of the electrode assembly or be placed on multiple outer surfaces. Correspondingly, the positions of the grooves 120 on the inner wall of the aluminum-plastic film should correspond to the positions of the adhesive 201. Before assembly, the correspondence between the grooves 120 and the adhesive 201 must be pre-defined to ensure spatial matching.

[0038] Then, the electrode assembly is covered with an aluminum-plastic film with grooves 120. While covering, the multiple grooves 120 correspond to the positions where the adhesive 201 is set on the electrode assembly, and it is ensured that the projected area of ​​the multiple grooves 120 on the surface of the electrode assembly is larger than the area of ​​the adhesive 201, so as to reserve enough space for subsequent gas discharge.

[0039] During the core baking process, the adhesive 201 is activated under high temperature and generates gas, which is promptly discharged through the pre-designed groove 120. For example, the groove 120 allows the gas to escape into a space outside the bonding area between the adhesive 201 and the aluminum-plastic film. The gas is then completely expelled from the battery through a subsequent pressurized formation process, or it can be introduced into a pre-designed air bladder, which is subsequently removed by cutting off the air bladder. This significantly reduces the presence of air bubbles between the adhesive 201 and the aluminum-plastic film after the core baking process, achieving a larger effective bonding area. Simultaneously, some of the molten material from the heated adhesive 201 can embed into the groove 120, further enhancing the mechanical anchoring effect and bonding strength, giving the electrochemical device better drop resistance.

[0040] This application's technical solution effectively solves the technical problem of air bubbles generated in the hot melt adhesive adhesive 201 during the core baking process by constructing multiple grooves 120 at intervals on the inner wall of the aluminum-plastic film body 100a, and making the projected area of ​​the multiple grooves 120 on the electrode assembly surface larger than the area of ​​the adhesive 201. Specifically, when the adhesive 201 is activated during high-temperature baking, the generated gas can be discharged in time through the grooves 120, providing sufficient channel space for gas migration and effectively preventing gas from accumulating between the adhesive 201 and the inner wall of the aluminum-plastic film to form air bubble defects. By eliminating the air bubble problem, not only is the appearance quality of the electrochemical device significantly improved, bulging on the surface of the aluminum-plastic film avoided, and abnormal increases in the overall thickness of the device reduced, but the effective bonding area and bonding strength between the adhesive 201 and the inner wall of the aluminum-plastic film are also greatly improved. In addition, the mechanical anchoring structure formed by the partial embedding of the adhesive component 201 into the groove 120 further enhances the bonding strength, ensuring that the adhesive component 201 can fully exert its stress transmission and dispersion function, thereby effectively improving the reliability of the electrochemical device under mechanical stress such as drop impact, and avoiding battery damage or safety hazards caused by bonding failure.

[0041] Furthermore, multiple grooves 120 form a slot area on the inner wall of the main body 100a, with the edge of the slot area extending 0.5mm to 4mm beyond the edge of the adhesive 201. Specifically, the distance at which the two ends of the grooves 120 extend beyond the edge of the adhesive 201 can be adjusted according to actual application requirements. For example, this extension distance can be set to 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, or 4mm, etc. When the extension distance is 0.5mm, basic gas exhaust function can be provided while ensuring structural compactness; when the extension distance is 1mm to 2mm, good exhaust effect can be achieved in most application scenarios; when the extension distance is 3mm to 4mm, sufficient exhaust channel can be provided for applications with large-area adhesives 201 or high gas generation.

[0042] By extending the two ends of the groove 120 beyond the edge of the adhesive 201 by a set distance, it can be ensured that the gas generated when the adhesive 201 is activated can be smoothly discharged from both sides of the bonding area, preventing gas from accumulating in the central area of ​​the adhesive 201. At the same time, the extended portion can also provide buffer space for the thermal expansion of the adhesive 201, preventing internal stress caused by limited thermal expansion and further improving the bonding reliability.

[0043] Continue reading Figure 1 In this embodiment, the spacing between adjacent grooves 120 is D, the width of groove 120 is W, and they satisfy the following relationship:

[0044] D = W*(2~4);

[0045] W = 0.1 to 1.

[0046] In this embodiment, the width W of the groove 120 can be set to a value such as 0.1mm, 0.2mm, 0.3mm, 0.5mm, 0.8mm, or 1mm. The spacing D between adjacent grooves 120 can be such as 0.2mm, 0.4mm, 0.6mm, 1mm, 1.6mm, 2mm, 3mm, or 4mm, and the specific value is determined according to the above relationship based on the width of the groove 120.

[0047] Preferably, the spacing between two adjacent grooves 120 is 2 to 4 times the width of the groove 120. For example, when the width W of the groove 120 is 0.5 mm, according to the formula D = W * (2 to 4), the spacing D between adjacent grooves 120 is 1 mm to 2 mm; when the width W of the groove 120 is 0.8 mm, the spacing D between adjacent grooves 120 is 1.6 mm to 3.2 mm; when the width W of the groove 120 is 1 mm, the spacing D between adjacent grooves 120 is 2 mm to 4 mm.

[0048] By controlling the width and spacing of the grooves 120 to satisfy the above relationship, it is possible to ensure that the grooves 120 have sufficient venting capacity while maintaining the integrity and strength of the inner wall structure of the aluminum-plastic film. Too small a spacing will result in insufficient material wall thickness between adjacent grooves 120, affecting structural strength; too large a spacing will reduce venting efficiency and may cause gas to accumulate in certain areas. Optimizing these design parameters achieves the best balance between venting performance and structural strength, ensuring effective gas venting during the baking process of the electrochemical device, while maintaining the mechanical and sealing properties of the aluminum-plastic film.

[0049] Continue reading Figure 1In this embodiment, the main body 100a includes a nylon layer 101, an aluminum foil layer 102, and a PP layer 103 stacked sequentially. The aluminum foil layer 102 is bonded to the nylon layer 101 and the PP layer 103 by an adhesive layer 104. A plurality of grooves 120 are formed on the surface of the PP layer 103 facing away from the aluminum foil layer 102. The thickness of the PP layer 103 is H1, and the depth of the grooves 120 is H, satisfying the following relationship:

[0050] H≤0.5*H1.

[0051] In this embodiment, the depth of the groove 120 should be less than or equal to 50% of the thickness of the PP layer 103. By controlling the depth of the groove 120, it is ensured that it will not penetrate the PP layer 103, thereby maintaining the integrity and sealing performance of the aluminum-plastic film.

[0052] For example, when the thickness of PP layer 103 is 50μm, the depth H of groove 120 is calculated to be 25μm according to the formula H≤0.5×H1; when the thickness of PP layer 103 is 60μm, the depth H of groove 120 is calculated to be 30μm according to the formula; when the thickness of PP layer 103 is 80μm, the depth H of groove 120 is calculated to be 40μm according to the formula.

[0053] By controlling the depth of the groove 120 to not exceed half the thickness of the PP layer 103, it can be ensured that the groove 120 provides an effective venting channel without compromising the structural integrity of the PP layer 103. This ensures that the groove 120 has sufficient volume to accommodate and vent the gas generated when the adhesive 201 is activated, while also ensuring that the PP layer 103 maintains sufficient wall thickness to perform its sealing function, preventing electrolyte leakage or external moisture intrusion.

[0054] Preferably, the depth of the groove 120 is 5μm to 40μm. In this embodiment, taking the PP layer 103 thickness of 80μm as an example, the depth of the groove 120 can be 5μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm or 40μm, etc.

[0055] Specifically, when the groove 120 depth is 5μm, it can provide basic venting function and is suitable for applications where the amount of gas produced by the adhesive 201 is low; when the groove 120 depth is 10μm to 20μm, it can meet the venting requirements of conventional hot melt adhesive adhesive 201 and performs well in most applications; when the groove 120 depth is 25μm to 35μm, it can provide a larger gas containment space and is suitable for applications with large-area bonding or high-temperature activation conditions; when the groove 120 depth is 40μm, it can cope with special application scenarios with large gas production while still maintaining 10350% of the remaining thickness of the PP layer.

[0056] Regardless of the depth value chosen, the groove 120 does not penetrate the PP layer 103. Even with a maximum depth of 40μm, when the PP layer 103 thickness is 80μm, a 40μm thickness of PP layer 103 is still maintained, ensuring the sealing integrity of the aluminum-plastic film. This ensures the effective venting function of the groove 120 while maintaining the basic performance requirements of the PP layer 103 as a sealing layer, avoiding structural weaknesses or potential leakage risks caused by an excessively deep groove 120. By rationally selecting the groove 120 depth, an optimal balance can be achieved between venting effectiveness and structural safety.

[0057] In some embodiments, the groove 120 is U-shaped; or, the groove 120 is V-shaped. When the groove 120 is U-shaped, its cross-section has an arc-shaped bottom and vertical sidewalls. The U-shaped groove 120 has a larger cross-sectional area and volume, which can provide better venting effect, while the arc-shaped bottom design helps to reduce stress concentration and improve the structural strength of the PP layer 103. In addition, the shape of the U-shaped groove facilitates the embedding of the adhesive 201 after melting, forming a good mechanical anchoring effect.

[0058] When the groove 120 is V-shaped, its cross-section exhibits a wedge-shaped structure with a sharp bottom and sloping sidewalls. The V-shaped groove 120 has the advantage of relatively simple manufacturing process and can be precisely formed through methods such as laser etching. While ensuring basic venting function, the V-shaped design has relatively low requirements for the thickness of the PP layer 103, making it suitable for applications where the PP layer 103 is thin. Simultaneously, the wedge-shaped structure of the V-groove facilitates directional gas flow, improving venting efficiency.

[0059] Both types of grooves 120 with different cross-sectional shapes can effectively achieve the gas discharge function. The specific choice can be determined comprehensively based on factors such as the thickness of the PP layer 103, manufacturing process requirements, and exhaust performance requirements, to ensure that the best exhaust effect and structural stability can be obtained under different application conditions.

[0060] There are various ways to arrange the grooves 120, such as extending along the width direction F of the main body 100a, extending along the length direction E of the main body 100a, or even crisscrossing them. The specific arrangement can be selected according to the distribution position of the adhesive 201 and the venting requirements. See details. Figure 2In this embodiment, multiple grooves 120 are sequentially spaced along the length direction E of the main body 100a and extend along the width direction F of the main body 100a. Specifically, the grooves 120 have a strip-like structure, with their length direction arranged along the width direction F of the main body 100a, and multiple grooves 120 are arranged sequentially at a preset interval along the length direction E of the main body 100a. When the adhesive 201 is activated and generates gas, the gas can flow rapidly along the width direction F of the grooves 120 and be discharged from both ends, avoiding accumulation in the center of the adhesive area. At the same time, the spaced distribution of multiple grooves 120 along the length direction E ensures that the entire adhesive area is covered by corresponding exhaust channels, achieving comprehensiveness and uniformity of the exhaust function. In addition, this lateral extension arrangement is also easy to match with the structure of the electrode assembly, and can adapt to the layout requirements of adhesives 201 of different sizes and shapes, ensuring good exhaust effect and adhesive performance in various application scenarios.

[0061] See Figure 3 In this embodiment, multiple grooves 120 are sequentially spaced along the width direction F of the main body 100a and extend along the length direction E of the main body 100a. The grooves 120 in this embodiment have a strip-like structure, extending along the length direction E of the main body 100a, and the multiple grooves 120 are arranged sequentially at a predetermined interval along the width direction F of the main body 100a. When the adhesive 201 is activated to generate gas, the gas can flow along the length direction E of the grooves 120 and be discharged from both the upper and lower ends, forming a longitudinal exhaust channel.

[0062] See Figure 4 In this embodiment, the groove 120 is a first groove 121 and a second groove 122. The first groove 121 extends along the length direction E of the main body 100a, and the second groove 122 extends along the width direction F of the main body 100a. The first groove 121 and the second groove 122 are intersecting.

[0063] In this embodiment, the first groove 121 and the second groove 122 intersect each other perpendicularly to form a grid-like exhaust channel structure. Specifically, a plurality of first grooves 121 are distributed in parallel and extend longitudinally along the length direction E of the main body 100a, and a plurality of second grooves 122 are distributed in parallel and extend laterally along the width direction F of the main body 100a. The two sets of grooves intersect each other in space, forming a deeper convergence area at the intersection point.

[0064] The intersecting groove network 120 provides multi-directional exhaust paths for the gas. Gas can be discharged longitudinally through the first groove 121 or laterally through the second groove 122, improving exhaust efficiency and reliability. Secondly, the deep groove areas formed at the intersections can serve as temporary gas storage spaces, effectively alleviating instantaneous gas generation pressure. Furthermore, the grid-like groove structure 120 can divide the bonding area into multiple relatively independent small regions. Even if the exhaust channel in one region is blocked, other regions can still exhaust normally, improving the overall system's fault tolerance.

[0065] In addition, the cross-shaped grooves 120 facilitate the multi-directional embedding of the adhesive 201 after melting, forming a more complex mechanical anchoring structure, further enhancing the bonding strength and anti-peeling performance, and ensuring the reliability of the electrochemical device under various mechanical stresses.

[0066] Furthermore, the intersection angle between the first groove 121 and the second groove 122 is 30° to 160°. In this embodiment, the intersection angle between the first groove 121 and the second groove 122 can be adjusted according to specific exhaust requirements and structural requirements. Specifically, the intersection angle can be set to values ​​such as 30°, 40°, 50°, 60°, 70°, 80°, 90°, 100°, 110°, 120°, 130°, 140°, 150°, or 160°.

[0067] When the intersection angle is 90°, the first groove 121 and the second groove 122 intersect perpendicularly, forming a standard orthogonal grid structure. This arrangement is structurally regular, easy to manufacture, and provides a balanced and stable exhaust effect. When the intersection angle is between 30° and 60°, a smaller acute angle intersection is formed. This design is beneficial for the directional flow of gas and is suitable for applications requiring a specific exhaust direction. When the intersection angle is between 120° and 160°, a larger obtuse angle intersection is formed, which can create a wider convergence area and provide a larger gas containment space.

[0068] Different cross angle designs can adapt to different adhesive component 201 layouts and venting requirements. Smaller cross angles facilitate rapid gas flow and are suitable for applications with high gas production and rapid venting; larger cross angles provide better gas buffering and are suitable for applications with relatively slow gas production but requiring sufficient venting. By optimizing the cross angles, the structural integrity and mechanical strength of the PP layer 103 can be maximized while ensuring venting performance.

[0069] The above description is only a part or preferred embodiment of this application. Neither the text nor the drawings should limit the scope of protection of this application. All equivalent structural transformations made using the content of this application's specification and drawings under the overall concept of this application, or direct / indirect applications in other related technical fields, are included within the scope of protection of this application.

Claims

1. An electrochemical device, characterized in that, The device includes an aluminum-plastic film and an electrode assembly. The aluminum-plastic film includes a main body, and the electrode assembly is disposed within the main body. An adhesive is provided on the outer surface of the electrode assembly. The inner wall of the main body is provided with a plurality of grooves at intervals. The adhesive is bonded to and engaged with the plurality of grooves. The sum of the projected areas of the plurality of grooves on the surface of the electrode assembly is greater than the projected area of ​​the adhesive on the surface of the electrode assembly.

2. The electrochemical device according to claim 1, characterized in that, The plurality of grooves form a slot area on the inner wall of the main body, and the edge of the slot area extends 0.5 mm to 4 mm beyond the edge of the adhesive.

3. The electrochemical device according to claim 2, characterized in that, The distance between adjacent grooves is D, the width of the groove is W, and the following relationship is satisfied: D = W*(2~4); W＝0.1～1。 4. The electrochemical device according to claim 3, characterized in that, The main body comprises a nylon layer, an aluminum foil layer, and a PP layer stacked sequentially. The aluminum foil layer is bonded to the nylon layer and the PP layer via an adhesive layer. Multiple grooves are formed on the surface of the PP layer facing away from the aluminum foil layer. The thickness of the PP layer is H1, and the depth of the grooves is H, satisfying the following relationship: H≤0.5*H1.

5. The electrochemical device according to claim 4, characterized in that, The depth of the groove is 5μm to 40μm.

6. The electrochemical device according to claim 5, characterized in that, The groove is U-shaped; or the groove is V-shaped.

7. The electrochemical device according to claim 2 or 6, characterized in that, The plurality of grooves are distributed at intervals along the length of the main body and extend along the width of the main body.

8. The electrochemical device according to claim 2 or 6, characterized in that, The plurality of grooves are distributed at intervals along the width direction of the main body and extend along the length direction of the main body.

9. The electrochemical device according to claim 2 or 5, characterized in that, The groove includes a first groove and a second groove. The first groove extends along the length direction of the main body, and the second groove extends along the width direction of the main body. The first groove and the second groove intersect.

10. The electrochemical device according to claim 9, characterized in that, The intersection angle between the first groove and the second groove is 30° to 160°.

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