Battery shell and lithium ion battery

Abstract

The battery shell comprises a bottom wall, a side wall and a composite adhesive layer, the side wall surrounds the bottom wall and extends towards one end of the bottom wall, a containing cavity with an opening in one end is defined by the side wall and the bottom wall, the containing cavity is used for containing a roll core, and the side wall is used for being electrically connected with a negative electrode of the roll core; the composite adhesive layer comprises an insulating adhesive layer and a swelling adhesive layer, the insulating adhesive layer is arranged on the inner wall surface of the side wall and used for isolating the side wall from the positive electrode of the roll core, and the swelling adhesive layer is arranged on the surface, opposite to the side wall, of the insulating adhesive layer and used for swelling after absorbing electrolyte. The insulating adhesive layer can effectively isolate the side wall from the positive electrode of the roll core, so that the situation that the side wall is possibly in accidental contact with the positive electrode of the roll core due to unexpected conditions is avoided, the risk of short circuit in the battery core is greatly reduced, the safety of the battery in the use process is improved, the swelling adhesive layer swells after absorbing electrolyte, and the service life of the battery is prolonged. The roll core is stabilized and buffered, and the stability of the whole structure of the battery is enhanced.

Description

Technical Field

[0001] This utility model relates to the field of lithium-ion battery technology, and in particular to a battery casing and a lithium-ion battery. Background Technology

[0002] In recent years, with the rapid development of science and technology, lithium-ion batteries have occupied an important position in many fields such as electronic devices, electric vehicles, and energy storage systems due to their high energy density and wide range of applications.

[0003] Among various battery configurations, cylindrical batteries are widely used due to their specific structural and performance characteristics. A common process in manufacturing cylindrical batteries is welding the negative electrode to the metal casing. This process has certain advantages. On the one hand, it effectively achieves electrical connections within the battery, ensuring smooth electron flow during charging and discharging, which plays a crucial role in the normal operation of the battery. On the other hand, it helps maintain the structural integrity of the battery. The welded connections provide mechanical support for internal components, keeping them in the correct position and stable, which is highly beneficial for the long-term performance and reliability of the battery.

[0004] However, significant safety issues exist in the actual use of cylindrical batteries. Because the negative electrode of a cylindrical battery is connected to the metal casing, the entire metal casing carries a negative charge during operation. In everyday use, cylindrical batteries inevitably encounter various complex situations. For example, when a cylindrical battery is exposed to frequent vibrations or subjected to external pressure, its internal structure may shift and deform, causing the metal casing to accidentally come into contact with the positive electrode. This can trigger an internal short circuit within the cell, generating a large amount of heat in a short time, leading to thermal runaway, and potentially even dangerous situations such as fire or explosion. Utility Model Content

[0005] The main purpose of this utility model is to propose a battery casing and a lithium-ion battery, which aims to solve the technical problem that cylindrical batteries, due to the negative electrode being connected to the metal casing and thus becoming charged, are prone to accidental contact between the metal casing and the positive electrode under complex conditions such as vibration and compression, leading to internal short circuits, thermal runaway, or even fire and explosion.

[0006] To achieve the above objectives, this utility model proposes a battery casing, comprising:

[0007] bottom wall;

[0008] A sidewall is provided, surrounding the bottom wall and extending to one end of the bottom wall, the sidewall and the bottom wall forming a receiving cavity with one end open, the receiving cavity being used to receive the winding core, and the sidewall being used to be electrically connected to the negative electrode of the winding core;

[0009] The composite adhesive layer includes an insulating adhesive layer and a swelling adhesive layer, wherein the insulating adhesive layer is disposed on the inner wall surface of the sidewall, and the swelling adhesive layer is disposed on the surface of the insulating adhesive layer facing away from the sidewall.

[0010] In some embodiments, the insulating adhesive layer is applied to the inner wall surface of the sidewall to form a continuous coating;

[0011] The swelling adhesive layer is coated on the surface of the insulating adhesive layer facing away from the sidewall, and the circumferential length of the swelling adhesive layer is less than the circumferential length of the insulating adhesive layer; and / or, the height of the swelling adhesive layer is less than the height of the insulating adhesive layer.

[0012] In some embodiments, the two ends of the swollen adhesive layer form notches at intervals in the circumferential direction on the inner wall surface of the sidewall, and the width of the notches in the circumferential direction of the sidewall is greater than or equal to 6 mm and less than or equal to 16 mm.

[0013] In some embodiments, the inner surface of the sidewall is provided with a coated area and an uncoated area in sequence along its height direction. The coated area is located near the opening, and the uncoated area is located near the bottom wall. The insulating adhesive layer is coated on the coated area.

[0014] In some embodiments, the uncoated area extends at a height greater than or equal to 2 mm and less than or equal to 6 mm in the sidewall height direction.

[0015] In some embodiments, in the height direction of the sidewall, the distance between the edge of the swelling adhesive layer near the opening and the edge of the sidewall opening is greater than or equal to 2 mm and less than or equal to 6 mm.

[0016] In some embodiments, the thickness of the insulating adhesive layer is greater than or equal to 1 μm and less than or equal to 10 μm.

[0017] In some embodiments, the thickness of the swollen adhesive layer is greater than or equal to 1 μm and less than or equal to 20 μm.

[0018] In some embodiments, the insulating adhesive layer is made of one or more of polyethylene terephthalate, polyvinyl chloride, polytetrafluoroethylene, and rubber; and / or,

[0019] The swelling adhesive layer is made of one or more of polyacrylic acid, polyacrylamide, and polyacrylate.

[0020] This utility model also provides a lithium-ion battery, comprising:

[0021] Battery casing;

[0022] The winding core is disposed within the receiving cavity of the battery casing;

[0023] The sidewall of the battery casing is electrically connected to the negative electrode of the winding core, and the composite adhesive layer of the battery casing is disposed between the winding core and the sidewall of the battery casing.

[0024] The battery casing provided in this application, by providing an insulating adhesive layer and a swelling adhesive layer on the inner wall of the sidewall, effectively isolates the sidewall from the positive electrode of the winding core, avoiding accidental contact between the sidewall and the positive electrode of the winding core due to unforeseen circumstances. This greatly reduces the risk of internal short circuits in the battery cell and improves the safety of the battery during use. The swelling adhesive layer swells after absorbing electrolyte, filling some tiny gaps inside the battery, stabilizing and buffering the winding core. This helps maintain the correct position of the winding core within the housing cavity, reducing the impact of winding core displacement caused by vibration and other factors on battery performance. It also effectively prevents the winding core from tilting due to shaking, which could cause the positive electrode of the winding core to contact the sidewall, thereby enhancing the overall structural stability of the battery and improving its long-term performance and reliability. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of one embodiment of the battery casing of this utility model;

[0026] Figure 2 This is a schematic diagram showing the unfolded shape of one embodiment of the sidewall of this utility model.

[0027] Explanation of icon numbers:

[0028] label name label name 100 Battery casing 10 bottom wall 20 sidewall 30 Opening 40 Receiving cavity 50 Composite adhesive layer 51 Insulating adhesive layer 52 Swelling adhesive layer 521 gap 21 Coated area 22 Uncoated area

[0029] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0030] The solutions in the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0031] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment 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.

[0032] 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.

[0033] Furthermore, the use of terms such as "first" and "second" in this utility model 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 by this utility model.

[0034] Please refer to Figure 1 and Figure 2 This application provides a battery casing 100, including a bottom wall 10, a side wall 20 and a composite adhesive layer 50; the side wall 20 surrounds the bottom wall 10 and extends to one end of the bottom wall 10, the side wall 20 and the bottom wall 10 form a receiving cavity 40 with an opening 30 at one end, the receiving cavity 40 is used to receive the winding core, and the side wall 20 is used to electrically connect to the negative electrode of the winding core.

[0035] The composite adhesive layer 50 includes an insulating adhesive layer 51 and a swelling adhesive layer 52. The insulating adhesive layer 51 is disposed on the inner wall surface of the side wall 20, and the swelling adhesive layer 52 is disposed on the surface of the insulating adhesive layer 51 facing away from the side wall 20.

[0036] In this embodiment, the battery casing 100 is composed of a bottom wall 10, a side wall 20 and a composite adhesive layer 50. The side wall 20 surrounds the bottom wall 10 to form a receiving cavity 40 for placing the winding core, and the side wall 20 is electrically connected to the negative electrode of the winding core to serve as part of the current conduction path when the battery is working normally.

[0037] The insulating adhesive layer 51 in the composite adhesive layer 50 is disposed on the inner wall surface of the side wall 20. Its main function is to prevent the side wall 20 (carrying a negative charge connected to the negative electrode of the core) from directly contacting the positive electrode of the core based on its insulating properties, thereby avoiding accidental short circuits when the battery is working normally.

[0038] The swelling adhesive layer 52 is disposed on the surface of the insulating adhesive layer 51 facing away from the sidewall 20. When electrolyte is injected into the battery, the swelling adhesive layer 52 absorbs the electrolyte and swells after absorbing the electrolyte due to its material properties. The swelling effect allows the swelling adhesive layer 52 to form a tighter contact and filling between the core and the winding core. On the one hand, this further enhances the fixing and cushioning effect on the winding core, and on the other hand, it can also reasonably fill and seal the internal space of the battery to a certain extent, preventing electrolyte leakage and other issues.

[0039] In this embodiment, by providing an insulating adhesive layer 51 and a swelling adhesive layer 52 on the inner wall of the side wall 20, the insulating adhesive layer 51 effectively isolates the side wall 20 from the positive electrode of the core, avoiding accidental contact between the side wall 20 and the positive electrode of the core due to unforeseen circumstances. This greatly reduces the risk of internal short circuits in the cell, decreases the probability of thermal runaway, fire, explosion, and other dangerous situations, and improves the safety of the battery during use. The swelling adhesive layer 52 swells after absorbing electrolyte, filling some tiny gaps inside the battery. This stabilizes and buffers the core, helping to maintain its correct position within the housing cavity 40, reducing the impact of core displacement due to vibration and other factors on battery performance. It also effectively prevents the core from tilting due to shaking, which could cause the positive electrode of the core to contact the side wall 20, thereby enhancing the overall structural stability of the battery and improving its long-term performance and reliability.

[0040] In some embodiments, an insulating adhesive layer 51 is applied to the inner wall surface of the sidewall 20 to form a continuous coating.

[0041] The swelling adhesive layer 52 is coated on the surface of the insulating adhesive layer 51 facing away from the sidewall 20, and the circumferential length of the swelling adhesive layer 52 is less than the circumferential length of the insulating adhesive layer 51; and / or, the height of the swelling adhesive layer 52 is less than the height of the insulating adhesive layer 51.

[0042] The insulating adhesive layer 51 is coated on the inner wall surface of the sidewall 20 to form a continuous coating, constructing a complete insulating and protective coating. Specifically, the continuous coating can cover the area where the sidewall 20 may come into contact with the positive electrode of the core, and utilizes the insulating properties of the insulating adhesive layer 51 to block charge conduction from all directions. This continuous structure that is tightly fitted to the sidewall 20 can continue to perform its insulating function even when the battery is subjected to external forces that cause slight displacement of the internal structure, ensuring battery safety.

[0043] When the swollen adhesive layer 52 absorbs the electrolyte and swells, it expands in all directions and vertically. Its circumferential and / or vertical dimensions are smaller than those of the insulating adhesive layer 51. This prevents the insulating adhesive layer 51 from being damaged by excessive compression during expansion, thus avoiding insulation failure due to the expansion of the swollen adhesive layer 52. Simultaneously, the non-full-coverage design of the swollen adhesive layer 52 allows it to form appropriate contact pressure with the core after swelling, ensuring effective fixation of the core without damaging it due to excessive pressure.

[0044] In this embodiment, the continuous insulating adhesive layer 51 significantly improves the reliability of insulation, reduces the possibility of accidental contact between the sidewall 20 and the positive electrode of the core, and lowers the risk of short circuits. The design of the swelling adhesive layer 52, smaller than the insulating adhesive layer 51, prevents damage to the insulation layer during the swelling process, further ensuring the insulation safety of the battery throughout its entire lifespan. The insulating adhesive layer 51 and the swelling adhesive layer 52 work synergistically to build a double line of defense for safe battery operation.

[0045] In actual production, the continuous coating of the insulating adhesive layer 51 facilitates the use of automated spraying and other processes, improving production efficiency. The non-full coverage design of the swelling adhesive layer 52 reduces the amount of adhesive material used, thereby lowering production costs.

[0046] In some embodiments, the two ends of the swollen adhesive layer 52 are spaced apart by notches 521 on the circumferential direction of the inner wall surface of the sidewall 20, and the width of the notches 521 in the circumferential direction of the sidewall 20 is greater than or equal to 6 mm and less than or equal to 16 mm.

[0047] like Figure 2 The diagram shows the unfolded sidewall 20. The width of the notch 521 along the circumferential direction of the sidewall 20 is D1, satisfying: 6mm ≤ D1 ≤ 16mm, where D1 = d1 + d2, 1mm ≤ d1 ≤ 6mm, and 5mm ≤ d2 ≤ 10mm. When the swelling adhesive layer 52 absorbs the electrolyte and swells, the notch 521 provides the necessary space for the expansion of the swelling adhesive layer 52. The size range of d1 and d2 ensures that the notch 521 can accommodate the moderate expansion of the swelling adhesive layer 52 without being too large and affecting the fixing effect of the swelling adhesive layer 52 on the core.

[0048] When the swelling adhesive layer 52 absorbs electrolyte and swells, the presence of the notch 521 provides a buffer space for the expansion of the swelling adhesive layer 52. During the swelling process, the swelling adhesive layer 52 will stretch and occupy more space. Without the notch 521, the excessively expanded swelling adhesive layer 52 may exert excessive pressure on the insulating adhesive layer 51 and the core. The notch 521 allows the swelling adhesive layer 52 to extend circumferentially towards the notch 521, preventing the insulating adhesive layer 51 from cracking or the core from deforming due to excessive compression. At the same time, the area of ​​the notch 521 also facilitates the flow and diffusion of electrolyte inside the battery, allowing the swelling adhesive layer 52 to absorb electrolyte more evenly and achieve a more stable swelling effect.

[0049] In this embodiment, the design of the notch 521 effectively prevents the excessive expansion of the swelling adhesive layer 52 from damaging the insulating adhesive layer 51, ensuring that the insulating adhesive layer 51 continues to function as an insulator between the sidewall 20 and the core positive electrode, further reducing the risk of short circuits. Furthermore, the uniform and stable swelling process reduces the possibility of damage to the internal battery structure caused by localized stress concentration, thus reducing the risk of thermal runaway.

[0050] In some embodiments, the inner surface of the sidewall 20 is provided with a coated area 21 and an uncoated area 22 in sequence along its height direction. The coated area 21 is located near the opening 30, and the uncoated area 22 is located near the bottom wall 10. The insulating adhesive layer 51 is coated on the coated area 21.

[0051] During battery assembly, when the core is placed into the receiving cavity 40, the area near the opening 30 is a critical region for the connection between the core's positive electrode and the outside, and it is also the location where the side wall 20 is most likely to accidentally come into contact with the core's positive electrode. Therefore, an insulating adhesive layer 51 is installed in this area to precisely insulate and protect this high-risk area. The uncoated area 22, near the bottom wall 10, provides a pathway for the electrical connection between the side wall 20 and the bottom core's negative electrode, ensuring normal electronic conduction of the battery.

[0052] In this embodiment, the clear division between the coated area 21 and the uncoated area 22 makes the coating of the insulating adhesive layer 51 more targeted and better suited to the actual needs inside the battery. Specifically, the clearly defined coated area 21 facilitates precise operation of automated coating equipment, improves production efficiency, and reduces product defect rates caused by inaccurate coating.

[0053] In some embodiments, the uncoated area 22 extends at a height D2 in the height direction of the sidewall 20, which is greater than or equal to 2 mm and less than or equal to 6 mm.

[0054] The extension height of the uncoated area 22 in the height direction of the sidewall 20 is limited to greater than or equal to 2 mm and less than or equal to 6 mm. This height range ensures sufficient contact area between the sidewall 20 and the bottom core negative electrode, enabling stable electron conduction and ensuring normal battery charging and discharging. If the height is less than 2 mm, the contact area is insufficient, which may lead to increased contact resistance and affect the battery's electrical performance. If the height is greater than 6 mm, it will reduce the insulating protection area of ​​the coated area 21, increasing the risk of accidental short circuit between the sidewall 20 and the core positive electrode.

[0055] In this embodiment, the limited height range of the uncoated area 22 ensures electrical connection while maximizing the insulation protection area of ​​the coated area 21. The coated area 21 near the opening 30 can effectively isolate the sidewall 20 from the core positive electrode, reducing the risk of short circuit, while the uncoated area 22 will not affect the insulation effect due to excessive height. This dual protection ensures battery safety and reduces the hidden dangers of thermal runaway, fire, and explosion.

[0056] In some embodiments, in the height direction of the sidewall 20, the distance D3 between the edge of the swelling adhesive layer 52 near the opening 30 and the edge of the sidewall 20 near the opening 30 is greater than or equal to 2 mm and less than or equal to 6 mm.

[0057] In this embodiment, in the height direction of the sidewall 20, a gap distance of greater than or equal to 2 mm and less than or equal to 6 mm is provided between the edge of the swelling adhesive layer 52 near the opening 30 and the edge of the sidewall 20 near the opening 30. This provides space for the swelling adhesive layer 52 to expand towards the opening 30 during swelling, preventing the swelling adhesive layer 52 from expanding excessively to the opening 30. This avoids structural interference during the assembly of components such as the core and battery cover due to compression, ensuring the compactness and stability of the overall battery structure. Moreover, the appropriate gap facilitates the flow and penetration of electrolyte in the battery opening 30 area, allowing the swelling adhesive layer 52 to absorb electrolyte more evenly and achieve stable swelling. It also helps maintain the balance of electrolyte concentration inside the battery.

[0058] In some embodiments, the thickness of the insulating adhesive layer 51 is greater than or equal to 1 μm and less than or equal to 10 μm.

[0059] In this embodiment, the thickness range ensures that the insulating adhesive layer 51 can effectively isolate the sidewall 20 from the core positive electrode, forming a stable insulating barrier, significantly reducing the risk of short circuits, ensuring the safe operation of the battery under various operating conditions, and reducing the hidden dangers of thermal runaway, fire, and explosion caused by short circuits. If the thickness is less than 1 μm, the insulating adhesive layer 51 may have weak points and cannot fully isolate charge conduction; while when the thickness exceeds 10 μm, although the insulation performance will be improved, it will increase the weight and volume of the insulating adhesive layer 51, affecting the energy density of the battery. At the same time, an excessively thick insulating adhesive layer 51 will also reduce the utilization rate of the battery's internal space.

[0060] In some embodiments, the thickness of the swollen adhesive layer 52 is greater than or equal to 1 μm and less than or equal to 20 μm.

[0061] In this embodiment, the thickness range ensures that the swelling adhesive layer 52 fully absorbs the electrolyte, generates appropriate expansion force, tightly adheres to the core, and firmly fixes it within the battery housing cavity 40. When the battery encounters vibration, impact, or other operating conditions, the swelling adhesive layer 52, with its good elasticity, effectively buffers external forces, prevents the core from shifting or deforming, maintains the stability of the battery's internal structure, and ensures the normal operation of the battery. If the thickness is less than 1 μm, the amount of electrolyte absorbed by the swelling adhesive layer 52 is limited, and it cannot generate sufficient expansion force to stabilize the core; while when the thickness exceeds 20 μm, excessive swelling of the swelling adhesive layer 52 may lead to excessive internal stress, which may not only squeeze the insulating adhesive layer 51 and damage its insulation performance, but also damage the core, affecting the stability of the battery's internal structure.

[0062] In some embodiments, the insulating adhesive layer 51 is made of one or more of polyethylene terephthalate, polyvinyl chloride, polytetrafluoroethylene, and rubber; and / or,

[0063] The swelling adhesive layer 52 is made of one or more of polyacrylic acid, polyacrylamide, and polyacrylate.

[0064] In this embodiment, the material properties of the insulating adhesive layer 51 and the swelling adhesive layer 52 determine the working principle of the battery casing 100. The insulating adhesive layer 51 is selected from one or more of polyethylene terephthalate, polyvinyl chloride, polytetrafluoroethylene, and rubber. Taking polytetrafluoroethylene as an example, its molecular structure has high carbon-fluorine bond energy and a compact structure, making it difficult for electrons to penetrate. It has extremely strong electrical insulation properties, which can isolate the sidewall 20 from the core positive electrode, block the charge conduction path, and prevent short circuits. Polyvinyl chloride and rubber also have excellent insulation properties due to their stable molecular structures, working together to ensure the safety of the charge distribution inside the battery.

[0065] The swelling adhesive layer 52 is made of one or more materials selected from polyacrylic acid, polyacrylamide, and polyacrylate. Polyacrylic acid molecules contain a large number of carboxyl groups. When solvent molecules in the electrolyte diffuse into the swelling adhesive layer 52, hydrogen bonds and other interactions form between the carboxyl groups and solvent molecules, causing the polyacrylic acid molecular chains to expand, resulting in macroscopic swelling. Polyacrylamide and polyacrylate achieve their swelling effect by relying on the polar groups on their molecular chains to interact with the electrolyte solvent. During the swelling process, the adhesive layer continuously fills the internal space of the battery, tightly adhering to the core.

[0066] This application embodiment also provides a lithium-ion battery, including a battery housing 100 and a winding core, wherein the winding core is disposed in the receiving cavity 40 of the battery housing 100;

[0067] The side wall 20 of the battery casing 100 is electrically connected to the negative electrode of the winding core, and the composite adhesive layer 50 of the battery casing 100 is disposed between the winding core and the side wall 20 of the battery casing 100.

[0068] Since the lithium-ion battery of this embodiment adopts all the technical solutions of all the embodiments of the above-mentioned battery casing 100, the lithium-ion battery of this utility model also has at least all the beneficial effects brought about by the technical solutions of the above-mentioned embodiments, which will not be described in detail here.

[0069] The above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make other variations or modifications based on the above description. It is impossible to exhaustively list all possible implementations here. All obvious variations or modifications derived from the technical solutions of this utility model are still within the protection scope of this utility model.

Claims

1. A battery case characterized by comprising: include: bottom wall; A sidewall is provided, surrounding the bottom wall and extending to one end of the bottom wall, the sidewall and the bottom wall forming a receiving cavity with one end open, the receiving cavity being used to receive the winding core, and the sidewall being used to be electrically connected to the negative electrode of the winding core; The composite adhesive layer includes an insulating adhesive layer and a swelling adhesive layer, wherein the insulating adhesive layer is disposed on the inner wall surface of the sidewall, and the swelling adhesive layer is disposed on the surface of the insulating adhesive layer facing away from the sidewall.

2. The battery case according to claim 1, wherein The insulating adhesive layer is applied to the inner wall surface of the sidewall to form a continuous coating. The swelling adhesive layer is coated on the surface of the insulating adhesive layer facing away from the sidewall, and the circumferential length of the swelling adhesive layer is less than the circumferential length of the insulating adhesive layer; and / or, the height of the swelling adhesive layer is less than the height of the insulating adhesive layer.

3. The battery case according to claim 2, characterized by The two ends of the swelling adhesive layer form notches at intervals in the circumferential direction on the inner wall surface of the side wall, and the width of the notches in the circumferential direction of the side wall is greater than or equal to 6 mm and less than or equal to 16 mm.

4. The battery case according to any one of claims 1 to 3, characterized by, The inner surface of the sidewall is provided with a coated area and an uncoated area along its height direction. The coated area is located near the opening, and the uncoated area is located near the bottom wall. The insulating adhesive layer is coated on the coated area.

5. The battery case according to claim 4, characterized by The uncoated area extends at a height greater than or equal to 2 mm and less than or equal to 6 mm in the direction of the sidewall height.

6. The battery case of claim 4, wherein, In the height direction of the sidewall, the distance between the edge of the swelling adhesive layer near the opening and the edge of the sidewall opening is greater than or equal to 2 mm and less than or equal to 6 mm.

7. The battery case according to any one of claims 1 to 3, characterized by, The thickness of the insulating adhesive layer is greater than or equal to 1 μm and less than or equal to 10 μm.

8. The battery case according to any one of claims 1 to 3, characterized by, The thickness of the swollen adhesive layer is greater than or equal to 1 μm and less than or equal to 20 μm.

9. The battery case according to any one of claims 1 to 3, characterized by, The insulating adhesive layer is made of one or more of polyethylene terephthalate, polyvinyl chloride, polytetrafluoroethylene, and rubber; and / or The swelling adhesive layer is made of one or more of polyacrylic acid, polyacrylamide, and polyacrylate.

10. A lithium-ion battery, characterized by, include: Battery casing as described in any one of claims 1 to 9; The winding core is disposed within the receiving cavity of the battery casing; The sidewall of the battery casing is electrically connected to the negative electrode of the winding core, and the composite adhesive layer of the battery casing is disposed between the winding core and the sidewall of the battery casing.

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