Battery cell

Abstract

The embodiment of the application discloses a battery monomer, and relates to the technical field of lithium batteries, wherein the battery monomer comprises a battery shell, a first cover plate, a second cover plate and a protective film, the battery shell is provided with a containing cavity with two open ends, the first cover plate and the second cover plate are respectively covered on the two openings, the protective film is sleeved on the battery shell, the protective film comprises a first adhesive layer, an aerogel layer, a second adhesive layer and an insulating layer, the aerogel layer is sleeved on the battery shell through the first adhesive layer, and the insulating layer is sleeved on the outer circumferential direction of the aerogel layer away from the battery shell through the second adhesive layer; in the technical scheme provided by the embodiment of the application, the nano-porous structure of the aerogel can effectively prevent water from penetrating, avoid water from penetrating into the battery core to cause damage to the battery core, and ensure that the battery pack still has good safety and reliability during transportation and in a humid environment.

Description

Technical Field

[0001] The embodiments in this application relate to the field of lithium battery technology, and in particular to a battery cell. Background Technology

[0002] A lithium battery cell is a secondary battery that uses lithium metal or lithium alloy as the negative electrode material and a non-aqueous electrolyte solution. It has advantages such as high energy density, long life and low self-discharge rate, and is widely used in portable electronic devices, electric vehicles and energy storage systems.

[0003] Batteries are used in a wide range of scenarios, often in harsh environments with condensation and water mist. During transportation, storage, and use, foreign objects and dust inevitably intrude into the gaps, affecting the insulation performance and safety of the battery cells.

[0004] Currently, battery protection is usually achieved by wrapping the battery cells with a PET blue film. However, water can seep in capillarily through the gaps in the blue film, causing water to enter the battery casing, leading to a short circuit and posing a risk of leakage. Utility Model Content

[0005] Several embodiments in this application propose a battery cell designed to further improve the waterproof performance of the battery.

[0006] One embodiment of this application provides a battery cell, which includes:

[0007] A battery housing, wherein the battery housing is provided with a receiving cavity having two openings;

[0008] A first cover plate is disposed over one of the openings in the battery casing;

[0009] A second cover plate, the second cover plate being disposed over another opening in the battery housing; and

[0010] A protective film is fitted over the battery casing;

[0011] The protective film includes a first adhesive layer, an aerogel layer, a second adhesive layer, and an insulating layer. The aerogel layer is fitted onto the battery casing through the first adhesive layer, and the insulating layer is fitted onto the outer periphery of the aerogel layer facing away from the battery casing through the second adhesive layer.

[0012] In one embodiment, the aerogel layer has a first surface and a second surface disposed opposite to each other, the first surface and the second surface being bonded and fixed to the first adhesive layer and the second adhesive layer, respectively.

[0013] In one embodiment, the thickness of the aerogel layer is greater than or equal to 0.5 mm and less than or equal to 10 mm.

[0014] In one embodiment, the first surface and / or the second surface is configured as a serrated surface.

[0015] In one embodiment, the first surface and / or the second surface is configured as a wavy surface.

[0016] In one embodiment, the battery cell includes at least two spaced aerogel layers, with an interlayer space formed between each pair of adjacent aerogel layers, and a third adhesive layer connecting the two adjacent aerogel layers is provided in the interlayer space.

[0017] In one embodiment, the surface of the aerogel layer is provided with a plurality of recesses;

[0018] At least a portion of the structure of the first adhesive layer and / or the second adhesive layer is disposed in the recess.

[0019] In one embodiment, the aerogel layer is one of a silicon aerogel layer, a ceramic aerogel layer, a carbon aerogel layer, a single oxide aerogel layer, a binary oxide aerogel layer, and a multi-component oxide aerogel layer.

[0020] In one embodiment, the first adhesive layer and / or the second adhesive layer is one of acrylic adhesives, polyacrylic adhesives, acrylate adhesives, and polyimide adhesives.

[0021] In several embodiments provided in this application, a protective film is provided on the outer surface of the battery casing to improve the sealing and waterproof performance of the battery cells, preventing rainwater and condensation from penetrating into the battery casing through capillary action and causing a short circuit between the cell and the battery casing. Specifically, the protective film includes a first adhesive layer, an aerogel layer, a second adhesive layer, and an insulating layer. The aerogel layer is fitted onto the battery casing through the first adhesive layer, and the insulating layer is fitted onto the aerogel layer facing away from the outer periphery of the battery casing through the second adhesive layer. The nanoporous structure of the aerogel can effectively prevent moisture penetration, avoiding damage to the cell caused by moisture infiltration, and ensuring that the battery pack still has good safety and reliability during transportation and in humid environments.

[0022] Moreover, when multiple battery cells mentioned above are combined to form a battery pack, the presence of the aerogel layer in the protective film can further optimize the heat insulation and explosion-proof performance between each pair of adjacent battery cells. The aerogel layer also has good flexibility, which can match the expansion and deformation of the battery cells well, without the need to reserve expansion displacement space, further compressing the volume of the battery pack. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments or prior art of this application, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0024] Figure 1 A schematic diagram of the structure of the protective film in the battery cell provided in this application;

[0025] Figure 2 for Figure 1 A schematic diagram of the cross-section of the protective membrane;

[0026] Figure 3 for Figure 2 A schematic diagram of the structure of the first embodiment of the intermediate aerogel layer;

[0027] Figure 4 for Figure 2 A schematic diagram of the structure of the second embodiment of the middle aerogel layer;

[0028] Figure 5 A schematic diagram of the structure of the protective film in the battery cell provided in this application;

[0029] Figure 6 A schematic diagram of the structure of the protective film in the battery cell provided in this application (third embodiment).

[0030] Figure 7 This is a schematic diagram of the structure of a single battery cell provided in this application;

[0031] Figure 8 This is a schematic diagram of the structure of a battery pack formed by combining multiple battery cells as provided in this application.

[0032] Explanation of icon numbers:

[0033] 100. Battery cell; 1. Battery casing; 11. First cover plate; 111. Positive electrode post; 112. Negative electrode post; 12. Second cover plate; 2. Protective film; 21. First adhesive layer; 22. Aerogel layer; 22a. First aerogel layer; 22b. Second aerogel layer; 221. Serrated surface; 222. Wavy surface; 223. Recess; 23. Second adhesive layer; 24. Insulating layer; 25. Third adhesive layer. Detailed Implementation

[0034] The technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings of several embodiments. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of 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.

[0035] It should be noted that if directional indications (such as up, down, left, right, front, back, etc.) are involved in multiple embodiments of this application, the directional indications are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0036] Furthermore, if multiple embodiments of this application involve descriptions such as "first" or "second," these descriptions are 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 with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text implies three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0037] Batteries are used in a wide range of environments, often in harsh conditions such as condensation and water mist. Furthermore, during transportation, storage, and use, foreign objects and dust inevitably intrude into the gaps, affecting the insulation performance and safety of the battery cells. Currently, battery protection is typically achieved by wrapping the individual battery cells with a PET blue film. However, water can seep in capillarily through the gaps in the blue film, causing water to enter the battery casing, leading to short circuits and posing a risk of leakage.

[0038] To address the aforementioned issues, this application proposes a single battery cell 100. For details, please refer to further references. Figures 1 to 8The battery cell 100 includes a battery housing 1, a first cover plate 11, a second cover plate 12, and a protective film 2. The battery housing 1 has a receiving cavity with openings at both ends. The first cover plate 11 and the second cover plate 12 respectively cover the two openings. The protective film 2 is sleeved on the battery housing 1. The protective film 2 includes a first adhesive layer 21, an aerogel layer, a second adhesive layer 23, and an insulating layer 24. The aerogel layer is sleeved on the battery housing 1 through the first adhesive layer 21, and the insulating layer 24 is sleeved on the aerogel layer through the second adhesive layer 23, facing away from the outer periphery of the battery housing 1.

[0039] In one embodiment of this application, the protective film 2 has a specific covering direction, that is, it covers from the opening of the first cover plate 11 towards the opening of the second cover plate 12, or from the opening of the second cover plate 12 towards the opening of the first cover plate 11. This ensures that the protective film 2 uniformly covers the surface of the battery cell 100, providing comprehensive protection, preventing direct contact between the internal components of the battery and the external environment, reducing corrosion, oxidation, and other problems caused by the external environment, thereby extending battery life. Secondly, the specific covering direction helps improve the safety performance of the battery, prevents internal short circuits, and reduces the risk of short circuits, fires, or even explosions caused by direct current flow between the positive and negative electrodes due to voltage differences during charging and discharging.

[0040] In the technical solution of this application, the battery cell 100 is generally square and has an upper end face, a lower end face, and a side face. The upper end face is the end face covered by the first cover plate 11, and the lower end face is the other end face opposite to the upper end face. The lower end face is covered by the second cover plate 12. The side face is the connecting surface configured to connect the upper end face and the lower end face, that is, the outer peripheral surface of the battery casing 1. In one embodiment of this application, taking a standard square battery cell 100 as an example, the side face includes four side face segments connected end to end in sequence. Each pair of adjacent side face segments is perpendicular to each other. The edges at the connection of the four side face segments are chamfered, so that the edges and corners become smooth, making it less likely to cause surface scratches, effectively protecting the aluminum casing, and ensuring the insulation of the current collector surface.

[0041] It should be noted that the aerogel layer 22 can be a membrane structure composed of a single aerogel layer, or a composite membrane structure composed of two or more multi-layer aerogel layers. This application does not limit this. The specific selection can be made adaptively based on factors such as the size, material, capacity, expansion amount of a single battery cell 100, and the actual usage environment of the battery. For example, when the battery is used in a high-humidity environment or an outdoor environment, multiple aerogel layers 22 should be set to ensure that the protective film 2 has multiple waterproof effects, thereby forming an effective waterproof seal for the battery cell 100. When the expansion amount of a single battery cell 100 during charging and discharging is large, multiple aerogel layers should be considered to ensure that the overall thickness of the aerogel layer 22 is also increased adaptively or the thickness of a single aerogel layer is increased, thereby meeting the expansion gap requirements between adjacent battery cells 100. The overall thickness of the aerogel layer 22 should not be less than the preset expansion displacement space size of a single battery cell 100 to meet the volume change requirements of the battery cell 100 during charging and discharging.

[0042] In several embodiments provided in this application, a protective film 2 is provided on the outer surface of the battery casing 1, thereby improving the sealing and waterproof performance of the battery cell 100 and preventing rainwater and condensation from penetrating into the battery casing 1 through capillary action, which could cause a short circuit between the cell and the battery casing 1. Specifically, the protective film 2 includes a first adhesive layer 21, an aerogel layer, a second adhesive layer 23, and an insulating layer 24. The aerogel layer is fitted onto the battery casing 1 through the first adhesive layer 21, and the insulating layer 24 is fitted onto the aerogel layer in the outer peripheral direction away from the battery casing 1 through the second adhesive layer 23. The nanoporous structure of the aerogel can effectively prevent moisture penetration, avoiding damage to the cell caused by moisture infiltration, and ensuring that the battery pack still has good safety and reliability during transportation and in humid environments.

[0043] Moreover, when multiple battery cells 100 mentioned above are assembled into a battery pack, the presence of the aerogel layer in the protective film 2 can further optimize the heat insulation and explosion-proof performance between each pair of adjacent battery cells 100. The aerogel layer also has good flexibility, which can match the expansion of the battery cells 100 and deform accordingly, without the need to reserve expansion displacement space, thus further compressing the volume of the battery pack.

[0044] Please refer to the accompanying drawings in the instruction manual. Figure 1 and Figure 2In the first embodiment of this application, the aerogel layer 22 is composed of only a single aerogel layer. The aerogel layer has a first surface and a second surface that are arranged opposite to each other, that is, arranged sequentially from the side of the battery cell 100 outwards. The first surface is bonded and fixed to the first adhesive layer 21, and correspondingly, the second surface is bonded and fixed to the second adhesive layer 23. The first surface of the aerogel layer is the side facing the side of the battery cell 100, and the second surface is the side facing away from the side of the battery cell 100. The aerogel layer is bonded and fixed to the side of the battery cell 100 by the first surface and the first adhesive layer 21, and the insulating layer 24 is bonded and fixed by the second surface and the second adhesive layer 23. In this way, the four-layer structure of the first adhesive layer 21, the aerogel layer, the second adhesive layer 23 and the insulating layer 24 together constitute the external protective film 2 of each individual battery cell 100. Because the protective film 2 includes an aerogel layer 22, it provides good heat insulation, deformation resistance, and waterproofing. Furthermore, since the outermost layer of the protective film 2 is an insulating layer 24, which is the blue film of the battery cell 100, the insulating layer 24 separates adjacent battery cells 100, preventing the impact of various faults of a single battery cell 100 on other battery cells 100, thus preventing "all batteries from being damaged if one is damaged". The insulating layer 24 can also prevent surface scratches and leakage of the battery during subsequent transportation and assembly, while also serving as a waterproof and dustproof agent, thereby better protecting the battery.

[0045] Please refer to the accompanying drawings in the instruction manual. Figure 5In the second embodiment of this application, the aerogel layer 22 consists of two layers, namely a first aerogel layer 22a and a second aerogel layer 22b. To ensure that the two aerogel layers 22 have good integrity and good composite structural strength, the first aerogel layer 22a and the second aerogel layer 22b are spaced apart in a direction from the side of the battery cell 100 outwards, and a third adhesive layer 25 is laid in the space. The purpose is to make the first aerogel layer 22a and the second aerogel layer 22b composite into an aerogel layer 22. In this embodiment, the two outer sidewalls of the aerogel layer 22 are the first surface of the first aerogel layer 22a and the second surface of the second aerogel layer 22b. The first aerogel layer 22a is bonded to the side of the battery cell 100, and the second aerogel layer 22b is bonded to the outermost insulating layer 24. In this embodiment, the aerogel layer 22 is configured as a composite film structure formed by bonding two aerogel layers 22 together. This design can improve the structural stability and mechanical strength of the aerogel layer 22. Since aerogel itself is brittle and easily damaged during processing and use, dividing it into two layers and bonding them together can reduce the risk of breakage due to physical impact or pressure. Simultaneously, the layered structure may help better manage thermal expansion and contraction, as the third adhesive layer 25 between the two aerogel layers can provide a certain degree of cushioning. Furthermore, the layered design may also help improve the thermal insulation performance of the aerogel pad; the third adhesive layer 25 can increase the heat conduction path, thereby further improving the thermal insulation effect.

[0046] Furthermore, based on the inventive concept provided in the second embodiment above, the protective film 2 can also include a multilayer structure composed of two or more layers of aerogel layers 22. Each pair of adjacent aerogel layers is bonded together by a third adhesive layer 25. Specifically, the aerogel layer 22, from the side of the battery cell 100 outwards, includes a first aerogel layer 22a, a third adhesive layer 25, a second aerogel layer 22b, a third adhesive layer 25… a (n-1)th aerogel layer, a third adhesive layer 25, and an nth aerogel layer, stacked sequentially. It should be noted that when the aerogel layer 22 is configured as a composite structure composed of multiple aerogel layers, the overall thickness of the aerogel layer 22 should be kept below 10mm to prevent a large film thickness from affecting the energy density and overall assembly quality of the battery pack.

[0047] It is understood that, based on the two embodiments described above, please refer to the accompanying drawings in the specification. Figure 6In the third embodiment of this application, the number of aerogel layers 22 is not limited, and can be one, two or more layers. In this embodiment, the adhesive layer is configured as multiple adhesive segments, and the multiple adhesive segments are set within the thickness of the aerogel layer. That is, multiple recesses 223 are provided on the first surface and / or the second surface of the aerogel layer. The recesses 223 can be multiple through strip grooves or multiple arrayed circular grooves. This application does not limit the specific shape and position of the recesses 223. In this embodiment, the recesses 223 are multiple evenly spaced strip grooves. The strip grooves are filled with adhesive layer, and the side of the adhesive layer facing away from the bottom of the groove is exposed on the surface of the aerogel layer, so as to ensure that it can be bonded and fixed to the insulating layer 24 or the side of the battery. It should be noted that multiple recesses 223 can be formed on the first surface of the aerogel layer, resulting in a flat second surface; or multiple recesses 223 can be formed on the second surface of the aerogel layer, resulting in a flat first surface; or multiple recesses 223 can be formed on both the first and second surfaces of the aerogel layer. This application does not limit this. The adhesive layer can be attached to the outer surface of the aerogel layer, filled in the grooves, or a combination of the above two methods. It should be noted that when recesses 223 are formed on both sides of the aerogel layer, the depth of the groove on one side should not exceed 1 / 3 of the aerogel layer thickness, so as to ensure that the recesses 223 on both sides do not penetrate or cause local thinning of the wall thickness, thus weakening the structural strength of the aerogel layer; correspondingly, a staggered arrangement can also be used to make the recesses 223 on both sides misaligned, thereby ensuring that no partial thinning of the structural wall thickness occurs.

[0048] In this third embodiment, it can also be combined with the first and second embodiments described above. That is, regardless of whether the aerogel layer 22 includes a single aerogel layer or two or more multi-layer aerogel layers, multiple recesses 223 can be formed on each aerogel layer to form a filling space that satisfies the third adhesive layer 25, thereby reducing the overall thickness of the protective film 2 and increasing the energy density of the battery cell 100 per unit volume.

[0049] It should be noted that the processing of the aerogel layer mainly includes adding a gelling agent to a solvent to prepare a gelling agent solution and stirring evenly. Next, a silicon source is added to the gelling agent solution and stirred evenly to form an aerogel precursor solution. Then, the aerogel precursor solution is poured into a mold for molding. The molded aerogel needs to be allowed to stand at room temperature for a period of time to gel. Finally, the gel sample is placed in a drying oven or vacuum drying oven for drying. After drying, the aerogel sample also needs to undergo heat treatment to further improve its thermal stability and pore structure. Based on the above processing, this application proposes a scheme using a non-smooth surface aerogel as the aerogel layer 22. Specifically, the cavity surface of the mold can be configured into various shapes such as serrated, pyramidal, wavy, and irregular. The non-smooth surface of the aerogel layer can further increase its contact area with the adhesive layer, improving the bonding strength and sealing performance between the two. The increased contact area means more surface area can come into contact with the adhesive, thereby enhancing the bond's stability and ensuring the structural stability of the battery cell 100 and preventing thermal runaway. Furthermore, this design improves the thermal insulation effect of the protective film 2 by increasing the heat conduction path, making it more difficult for heat to penetrate the aerogel layer 22. For further details, please refer to [link to relevant documentation]. Figure 3 and Figure 4 Aerogel layers with serrated surfaces 221 and wavy surfaces 222 are provided respectively. Furthermore, the serrated surface 221 can be a macroscopic structure or a microscopic structure, and this application does not limit it in this regard.

[0050] When designing the aerogel layer 22, the overall thickness of the aerogel layer 22 should be between 0.5 mm and 10 mm. When the aerogel layer 22 is a single aerogel layer, the thickness of the single aerogel layer should be no less than 1 mm and no more than 10 mm. When the aerogel layer 22 includes two aerogel layers, the thickness of the single aerogel layer should be no less than 0.25 mm and no more than 5 mm. When the aerogel layer 22 includes two or more multi-layer aerogel layers 22, the overall thickness range of the aerogel layer 22 should be followed for reasonable design. Each aerogel layer 22 can be of uniform thickness or unequal thickness, and this application does not impose any restrictions on this.

[0051] When designing the adhesive layer, the total thickness of the adhesive layer, including the first adhesive layer 21 and the second adhesive layer 23, should be between 5μm and 50μm, preferably between 30μm and 35μm. When the thickness of the adhesive layer is between 30μm and 35μm, its bonding stability is the best and the thickness is relatively moderate, which will not occupy a large proportion of the overall thickness of the protective film 2. The thickness of the first adhesive layer 21 and the second adhesive layer 23 can be a uniform thickness adhesive layer, or different thicknesses can be selected according to the actual situation. This application does not impose any restrictions on this.

[0052] Furthermore, the first adhesive layer 21 and / or the second adhesive layer 23 are one of acrylic adhesives, polyacrylic adhesives, acrylate adhesives, and polyimide adhesives, such as acrylate adhesives, acrylic emulsion adhesives, acrylate adhesives, etc.

[0053] It should be noted that the aerogel layer 22 is one of the following: silicon aerogel layer, ceramic aerogel layer, carbon aerogel layer, single oxide aerogel layer, binary oxide aerogel layer, and multi-element oxide aerogel layer 22. This application does not limit this, and it can be selected comprehensively based on factors such as the actual use scenario of the battery, battery materials, and manufacturing cost. Silica aerogel layers possess excellent mechanical properties, high-temperature insulation performance, and adsorption effects, making them suitable for applications requiring high insulation and mechanical strength. Ceramic aerogel layers, such as Al2O3 aerogel, exhibit excellent high-temperature thermal stability, making them suitable for the protection of battery cells in high-temperature environments. Carbon aerogel layers have higher porosity, specific surface area, and electrical conductivity, with a wider density range and application scope, making them suitable for applications requiring good electrical conductivity and insulation. Monomer oxide aerogel layers, such as TiO2 aerogel, possess unique photocatalytic properties, potentially contributing to the thermal management and environmental adaptability of battery cells. Binary oxide aerogel layers, such as binary oxide aerogels composed of Al2O3, SiO2, and ZrO2, can enhance the high-temperature insulation performance of Al2O3 aerogel, while ZrO2, as an excellent light-shielding material, can improve the thermal stability of the aerogel, making them suitable for high-temperature applications.

[0054] To ensure the electrical insulation performance of the battery cell 100, the outermost layer of the protective film 2 in this application is further provided with an insulating layer 24. The insulating layer 24 is a substrate layer made of polyethylene terephthalate (PET). PET material has good physical properties, such as high strength, wear resistance, tensile strength, tear resistance, and temperature resistance. It also has good transparency, optical properties, and electrical insulation properties. PET film has good chemical stability and can resist corrosion from most common chemicals. PET material can also maintain excellent physical properties over a wide temperature range, with high impact strength, abrasion resistance, good rigidity, high hardness, low moisture absorption, good dimensional stability, and excellent electrical properties. Due to its good insulation performance, chemical resistance, and physical properties, PET blue film can provide both electrical insulation and physical protection for power batteries. Furthermore, the thickness of the insulating layer 24 is 30μm to 100μm. The designed thickness of the insulating layer 24 is related to several parameters, including its physical performance requirements, chemical stability, temperature resistance, puncture resistance, and tensile strength. Specifically, the insulation layer 24 needs sufficient mechanical strength to protect the battery from physical damage, while also possessing good high-temperature and high-voltage resistance to adapt to the battery's operating conditions in different environments. Furthermore, the thickness design must consider the material's insulation performance and chemical corrosion resistance to ensure the battery's safe and stable operation. This ensures good insulation performance while maintaining sufficient mechanical strength; provides excellent electrolyte resistance and corrosion resistance; and offers excellent edge coverage for comprehensive protection.

[0055] Based on the aforementioned battery cells, this application also proposes a battery pack, which is an energy storage device composed of multiple battery cells connected in series and / or parallel. The battery pack typically consists of multiple battery cells connected in series and / or parallel. To prevent thermal runaway in a single battery cell from affecting other normally functioning cells, an additional expansion displacement space is reserved between every two adjacent battery cells. This reserved expansion displacement space is for effective control and management of expansion during battery charging and discharging. During charging and discharging, battery cells expand due to chemical reactions, causing deformation of the entire battery module. If the expansion is significant and the casing material cannot withstand this expansion force, it may cause safety issues and even affect the appearance and size of the module, leading to the battery module's outer contour exceeding specifications. Reserving appropriate expansion space ensures that the battery module does not exceed design boundaries during expansion, and also helps protect the structural integrity of the battery module, avoiding casing damage or battery performance degradation due to excessive expansion force.

[0056] In battery pack structural layout, aerogel pads are typically placed between two adjacent battery cells to separate them and prevent a chain reaction caused by the failure of one cell. However, reserving expansion displacement space and adding aerogel pads further increases the battery pack's volume, leading to a decrease in energy density per unit volume.

[0057] In the various embodiments provided in this application, a protective film 2 is provided on the surface of each battery cell 100, thereby ensuring good heat insulation and explosion-proof performance between each battery cell 100, especially between each adjacent pair of battery cells 100. Furthermore, the spatial layout of the battery cells 100 is optimized, and the assembly of the battery pack is simplified. Specifically, the protective film 2 includes a first adhesive layer 21, an aerogel layer 22, a second adhesive layer 23, and an insulating layer 24, which are sequentially stacked from the outer surface of the battery cell 100. The aerogel layer 22 is bonded and fixed to the outer surface of the battery cell 100 through the first adhesive layer 21, and on the other side, it is bonded and fixed to the insulating layer 24 through the second adhesive layer 23. In the battery pack, each pair of adjacent battery cells 100 abuts against each other through the protective film 2. The aerogel layer 22 not only has excellent heat insulation performance but also good flexibility, which can well match the expansion and deformation of the battery cells 100 without reserving expansion displacement space, further compressing the volume of the battery pack. The specific structure of the battery cell is as described in the above embodiments. Since this battery pack adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0058] Furthermore, the battery pack provided in this application can be used as a power source for electrical devices or as an energy storage unit for electrical devices. Electrical devices may include, but are not limited to, mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, range-extended vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.

[0059] The above description is merely an exemplary embodiment of this application and does not limit the patent scope of this application. Any equivalent structural transformations made based on the technical concept of this application and the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A battery cell, characterized in that, The battery cell includes: A battery housing, wherein the battery housing is provided with a receiving cavity having two openings; A first cover plate is disposed over one of the openings in the battery casing; A second cover plate, the second cover plate being disposed over another opening in the battery housing; and A protective film is fitted over the battery casing; The protective film includes a first adhesive layer, an aerogel layer, a second adhesive layer, and an insulating layer. The aerogel layer is fitted onto the battery casing through the first adhesive layer, and the insulating layer is fitted onto the outer periphery of the aerogel layer facing away from the battery casing through the second adhesive layer.

2. The battery cell as described in claim 1, characterized in that, The aerogel layer has a first surface and a second surface disposed opposite to each other, and the first surface and the second surface are respectively bonded and fixed to the first adhesive layer and the second adhesive layer.

3. The battery cell as described in claim 2, characterized in that, The thickness of the aerogel layer is greater than or equal to 0.5 mm and less than or equal to 10 mm.

4. The battery cell as described in claim 2, characterized in that, The first surface and / or the second surface are configured as serrated surfaces.

5. The battery cell as described in claim 2, characterized in that, The first surface and / or the second surface are configured as wavy surfaces.

6. The battery cell according to any one of claims 1 to 5, characterized in that, The battery cell includes at least two spaced aerogel layers, with a sandwich space formed between each pair of adjacent aerogel layers, and a third adhesive layer connecting the two adjacent aerogel layers is provided in the sandwich space.

7. The battery cell according to any one of claims 1 to 5, characterized in that, The surface of the aerogel layer is provided with multiple recesses; At least a portion of the structure of the first adhesive layer and / or the second adhesive layer is disposed in the recess.

8. The battery cell according to any one of claims 1 to 5, characterized in that, The aerogel layer is one of the following: silicon aerogel layer, ceramic aerogel layer, carbon aerogel layer, single oxide aerogel layer, binary oxide aerogel layer, and multi-component oxide aerogel layer.

9. The battery cell according to any one of claims 1 to 5, characterized in that, The total thickness of the first adhesive layer and the second adhesive layer is greater than or equal to 5 μm and less than or equal to 50 μm.

10. The battery cell according to any one of claims 1 to 5, characterized in that, The first adhesive layer and / or the second adhesive layer are one of acrylic adhesives, polyacrylic adhesives, acrylate adhesives, and polyimide adhesives.

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