Encapsulation film, electrochemical device, and electronic device

Abstract

The application discloses a packaging film, an electrochemical device and an electronic device. The packaging film comprises a first insulating layer, a metal layer, a second insulating layer and a melt adhesive layer. The metal layer is connected to the first insulating layer, and the second insulating layer is connected to the metal layer. The melt adhesive layer is connected to the surface of the metal layer away from the packaging film and / or the surface of the second insulating layer away from the metal layer. The resistivity and puncture resistance of the second insulating layer are both greater than those of the melt adhesive layer. The surface of the packaging film away from the first insulating layer has a receiving groove. The distance between the bottom wall of the receiving groove and the surface of the metal layer facing the second insulating layer is L1, and L1>0. The projection of the receiving groove on the metal layer does not protrude from the projection of the second insulating layer on the metal layer. That is, the packaging film of the embodiment is provided with the second insulating layer with higher puncture resistance and resistivity at the position where the melt adhesive layer is removed. Therefore, when the packaging film is used in the electrochemical device, the energy density can be improved on the basis of ensuring safety and service life.

Description

Technical Field

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

[0002] In some existing electrochemical devices, such as pouch cells, to improve energy density, the overall thickness of the pouch cell is reduced by thinning the PP (polypropylene) layer in the main cell area of ​​the encapsulation film, creating a gap in the PP layer with part of the cell located within the gap. However, due to the reduced PP layer thickness, mechanical and insulation properties will decrease to varying degrees, leading to a reduction in the safety and lifespan of the pouch cell. Utility Model Content

[0003] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes an encapsulation film that can be used to encapsulate battery cells, thereby improving the energy density of electrochemical devices while ensuring battery safety and lifespan.

[0004] This application also provides an electrochemical device including the above-described encapsulation membrane.

[0005] This application also provides an electronic device including the above-described electrochemical device.

[0006] An encapsulation film according to a first aspect embodiment of the present application is used to encapsulate a battery cell to form an electrochemical device, the electrochemical device including an encapsulation body formed by the encapsulation film, the encapsulation body having a receiving cavity, the battery cell being located within the receiving cavity, the encapsulation film including: a first insulating layer, a metal layer, a second insulating layer, and a molten adhesive layer.

[0007] The metal layer is connected to any surface of the first insulating layer in the first direction, where the first direction is the thickness direction of the first insulating layer; the second insulating layer is connected to the surface of the metal layer opposite to the first insulating layer; the molten adhesive layer is connected to the surface of the metal layer opposite to the encapsulation film and / or the surface of the second insulating layer opposite to the metal layer, wherein the resistivity of the second insulating layer is greater than the resistivity of the molten adhesive layer, and the puncture resistance of the second insulating layer is greater than the puncture resistance of the molten adhesive layer; and the surface of the encapsulation film opposite to the first insulating layer further has a receiving groove, the receiving groove having a first inner wall in the thickness direction of the encapsulation film, wherein in the first direction, the distance between the first inner wall and the surface of the metal layer facing the second insulating layer is L1, where L1 > 0; wherein, in the first direction, the projection of the receiving groove on the metal layer is a first projection, the projection of the second insulating layer on the metal layer is a second projection, and the first projection does not protrude beyond the second projection.

[0008] The encapsulation film according to the embodiments of this application has at least the following beneficial effects:

[0009] The encapsulation film of this embodiment has a receiving groove. In a first direction, the projection of the receiving groove onto the metal layer is a first projection, and the projection of the second insulating layer onto the metal layer is a second projection. The first projection does not protrude beyond the second projection. That is, the encapsulation film of this embodiment has a second insulating layer with higher puncture resistance and resistivity at the location where the molten adhesive layer is removed. When the encapsulation film of this embodiment is applied to an electrochemical device, the battery cell portion is located within the receiving groove, making the structure of the electrochemical device more compact. This improves the energy density of the battery. Furthermore, since the puncture resistance and resistivity of the second insulating layer are greater than those of the molten adhesive layer, the weakening of insulation and puncture resistance caused by removing the molten adhesive layer is reduced, thereby ensuring the safety and service life of the electrochemical device.

[0010] According to some embodiments of this application, in the first direction, the distance between the surface of the second insulating layer away from the metal layer and the first inner wall is L2, where L2≥0.

[0011] According to some embodiments of this application, the first projection is located within the range of the second projection, and the boundaries of the first projection and the boundaries of the second projection are spaced apart.

[0012] According to some embodiments of this application, the molten adhesive layer is attached to the surface of the second insulating layer opposite to the metal layer, and in the first direction, the projection of the molten adhesive layer on the metal layer is a third projection, which does not protrude from the second projection.

[0013] According to some embodiments of this application, the second projection is spaced apart from the edge of the metal layer.

[0014] According to some embodiments of this application, the molten adhesive layer is connected to the metal layer, and the boundary of the first projection coincides with the boundary of the second projection.

[0015] According to some embodiments of this application, the molten adhesive layer has two spaced-apart receiving grooves, the first inner walls of the two receiving grooves being respectively used to form two sidewalls of the receiving cavity in the thickness direction of the encapsulation body.

[0016] According to some embodiments of this application, the second insulating layer is prepared using a mixture of ceramic and polytetrafluoroethylene.

[0017] An electrochemical device according to a second aspect of this application includes: a battery cell and an encapsulation film according to a first aspect of this application. The battery cell includes a battery cell body and tabs connected to the battery cell body; the encapsulation film covers the battery cell body and forms a receiving cavity, the receiving cavity including the receiving groove, and a portion of the battery cell body is located within the receiving groove.

[0018] The electrochemical device according to the embodiments of this application has at least the following beneficial effects:

[0019] The encapsulation film of the first aspect embodiment has a receiving groove. In a first direction, the projection of the receiving groove onto the metal layer is a first projection, and the projection of the second insulating layer onto the metal layer is a second projection. The first projection does not protrude beyond the second projection. That is, the encapsulation film has a second insulating layer with higher puncture resistance and resistivity at the portion where the molten adhesive layer is removed. The battery cell portion is located within the receiving groove, making the structure of the electrochemical device more compact. This improves the energy density of the electrochemical device. Furthermore, since the puncture resistance and resistivity of the second insulating layer are greater than those of the molten adhesive layer, the weakening of insulation and puncture resistance caused by removing the molten adhesive layer is reduced, thereby ensuring the safety and service life of the electrochemical device of this embodiment.

[0020] According to some embodiments of this application, the inner wall of the receiving cavity is defined by the second insulating layer.

[0021] An electronic device according to a third aspect of this application includes: the electrochemical device described in the second aspect of this application.

[0022] The electronic device according to the embodiments of this application has at least the following beneficial effects:

[0023] The electrochemical device of the second aspect embodiment is specifically described in this embodiment. The electronic device employs the electrochemical device of the second aspect embodiment. The encapsulation film in the electrochemical device has a receiving groove. In a first direction, the projection of the receiving groove onto the metal layer is a first projection, and the projection of the second insulating layer onto the metal layer is a second projection. The first projection does not protrude beyond the second projection, meaning that the encapsulation film has a second insulating layer with higher puncture resistance and resistivity at the portion where the molten adhesive layer is removed. The battery cell body is located within the receiving cavity and partially within the receiving groove, making the structure of the electrochemical device more compact and thereby increasing the energy density of the electrochemical device. Furthermore, since the puncture resistance and resistivity of the second insulating layer are greater than those of the molten adhesive layer, the weakening of insulation and puncture resistance caused by removing the molten adhesive layer is reduced, ensuring the safety and service life of the electrochemical device, and thus improving the service life and safety of the electronic device.

[0024] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0025] The present application will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0026] Figure 1 It is a common type of encapsulation film currently available.

[0027] Figure 2 This is a cross-sectional view of a first type of encapsulation film according to the first aspect of this application;

[0028] Figure 3 for Figure 2 A magnified view of area A in the middle;

[0029] Figure 4 This is a cross-sectional view of the second type of encapsulation film according to the first aspect of this application;

[0030] Figure 5 for Figure 4 A magnified view of area B in the middle;

[0031] Figure 6 This is a cross-sectional view of the third type of encapsulation film according to the first aspect of this application;

[0032] Figure 7 This is a cross-sectional view of the fourth type of encapsulation film according to the first aspect of this application;

[0033] Figure 8 for Figure 7 Enlarged view of region C in the middle;

[0034] Figure 9 This is a cross-sectional view of the fifth type of encapsulation film according to the first aspect of this application;

[0035] Figure 10 This is a cross-sectional view of a first electrochemical device according to a second aspect embodiment of this application;

[0036] Figure 11 This is a cross-sectional view of a second type of electrochemical device according to a second aspect embodiment of this application;

[0037] Figure 12 This is a cross-sectional view of a third type of electrochemical device according to a second aspect embodiment of this application.

[0038] Figure label:

[0039] PP layer 1, notch 2;

[0040] First insulating layer 100, metal layer 200, second insulating layer 300, molten adhesive layer 400;

[0041] The receiving groove is 500, and the first inner wall is 510.

[0042] 600 cells

[0043] The main body of the package is 700, and the receiving cavity is 710. Detailed Implementation

[0044] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0045] In the description of this application, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0046] In the description of this application, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0047] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0048] In some existing electrochemical devices, such as pouch cells, to improve energy density, the overall thickness of the pouch cell is reduced by thinning the PP layer 1 of the encapsulation film located in the main body region of the cell, thereby forming a gap 2 in the PP layer 1. A portion of the cell 600 is located within the gap 2. Figure 1 (As shown). However, due to the reduced thickness of PP layer 1, the mechanical and insulation properties will decrease to varying degrees, resulting in a reduction in the safety and lifespan of the pouch battery.

[0049] In view of the above background, combined with Figures 2 to 12 This application proposes an encapsulation film that can be used to encapsulate a battery cell 600, thereby improving the energy density of the electrochemical device while ensuring battery safety and lifespan. Figures 2 to 10The dashed lines in the diagram should not be interpreted as the actual outline of the electrochemical device; they are merely for the purpose of more clearly showing the location of the containment tank 500.

[0050] In this embodiment, the encapsulation film is used to encapsulate the battery cell 600 to form an electrochemical device. The electrochemical device includes an encapsulation body 700 formed by the encapsulation film. The encapsulation body 700 has a receiving cavity 710, and the battery cell 600 is located within the receiving cavity 710. The encapsulation film includes: a first insulating layer 100, a metal layer 200, a second insulating layer 300, and a molten adhesive layer 400 (e.g., ...). Figure 2 (As shown).

[0051] The first insulating layer 100 is made of one or more insulating materials with a certain mechanical puncture resistance, such as nylon (PA), polyhydroxyalkanoate (PHA), polyester (PET), or polyethylene terephthalate (PI). The metal layer 200 is made of aluminum foil, steel foil, or composite metal foil, and is attached to any surface of the first insulating layer 100 in a first direction (the first direction is the thickness direction of the first insulating layer 100).

[0052] The second insulating layer 300 is attached to the surface of the metal layer 200 facing away from the first insulating layer 100. The thickness of the second insulating layer 300 is, for example, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 10 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm, or falls within any two of the above values. The second insulating layer 300 is made of, for example, ceramic insulating material, meta-aramid (PMIA), or poly(p-phenylenebenzodioxazole) (PBO) fiber. Preferably, in some embodiments, the second insulating layer 300 is formed using a mixture of ceramic and polytetrafluoroethylene. Specifically, polytetrafluoroethylene (PTFE) is used to firmly bond ceramics to the surface of the metal layer 200. The ceramics include, for example, at least one of alumina, alumina hydrate, gibbsite, silicon dioxide, magnesium oxide, magnesium hydroxide, titanium dioxide, BaTiO2, ZrO, alumina-silica composite oxides, aluminum nitride, boron nitride, organosilicon, diamond, barium sulfate, calcium fluoride, barium fluoride, talc, or montmorillonite. The ceramics have high resistivity, effectively isolating the aluminum layer from direct contact with the electrolyte, preventing electrochemical corrosion and short circuits. Furthermore, alumina has strong wear resistance, reducing the risk of damage from impacts with the battery cell 600 during use, thus improving the safety of the electrochemical device. In addition, PTFE has an absorption rate of less than 10% for lasers with wavelengths of 0.25μm-2.5μm, while the ceramics have an absorption rate of approximately 3% for fiber lasers with wavelengths of around 1.06μm. Therefore, during the processing, a fiber laser with a wavelength of about 1.06 μm can be used to remove the molten adhesive layer 400 to form the receiving groove 500. Since the second insulating layer 300 has a low laser absorption rate, it can not only reduce the risk of the second insulating layer 300 separating from the metal layer 200, but also reduce the damage of the laser to the metal layer 200, thereby making the encapsulation film of this embodiment have higher quality.

[0053] The molten adhesive layer 400 is made of, for example, polypropylene (PP), modified polypropylene, polybutylene terephthalate (PBT), or polyetheretherketone (PEEK). The molten adhesive layer 400 is attached to the surface of the metal layer 200 opposite to the encapsulation film and / or the surface of the second insulating layer 300 opposite to the metal layer 200. For example, the molten adhesive layer 400 is only attached to the metal layer 200, or the molten adhesive layer 400 is only attached to the second insulating layer 300, or a portion of the molten adhesive layer 400 is attached to the metal layer 200 and a portion is attached to the second insulating layer 300. The resistivity of the second insulating layer 300 is greater than that of the molten adhesive layer 400, and the puncture resistance of the second insulating layer 300 is greater than that of the molten adhesive layer 400. The surface of the encapsulation film facing away from the first insulating layer 100 also has a receiving groove 500. The receiving groove 500 has a first inner wall 510 in a first direction (the thickness direction of the encapsulation film). In the first direction, the distance between the first inner wall 510 and the surface of the metal layer 200 facing the second insulating layer 300 is L1, where L1 > 0 (e.g., ...). Figure 3 As shown in the figure, L1 can be 1μm, 2μm, 3μm, 4μm, 5μm, 10μm, 6μm, 7μm, 8μm, 9μm, 10μm, 15μm, 20μm, 25μm, 30μm, or 40μm, or within any two of the above values, as long as the side of the encapsulation film facing away from the first insulating layer 100 has a receiving groove 500, and the first inner wall 510 of the receiving groove 500 has a second insulating layer 300 between it and the metal layer 200. For example, the receiving groove 500 is completely formed within the molten adhesive layer 400, and the depth of the receiving groove 500 is less than the thickness of the molten adhesive layer 400, that is, a portion of the molten adhesive layer 400 is retained at the receiving groove 500. Alternatively, the receiving groove 500 extends from the molten adhesive layer 400 to the second insulating layer 300, and the second insulating layer 300 is exposed from the receiving groove 500, that is, the molten adhesive layer 400 at the receiving groove 500 is completely removed. That is, in some embodiments described below, in the first direction, the distance between the surface of the second insulating layer 300 facing away from the metal layer 200 and the first inner wall 510 is L2, where L2≥0 (e.g., Figure 4 and Figure 5 As shown), L2 is, for example, 0, 1μm, 2μm, 3μm, 4μm, 5μm, 10μm, 15μm, 20μm, 25μm or 30μm, or within the range of any two of the above values.

[0054] In the first direction, the projection of the receiving groove 500 onto the metal layer 200 is the first projection, and the projection of the second insulating layer 300 onto the metal layer 200 is the second projection. The first projection does not protrude beyond the second projection. That is, in this embodiment, the encapsulation film has a second insulating layer 300 with higher puncture resistance and resistivity at the location where the molten adhesive layer 400 is removed. When the encapsulation film of this embodiment is applied to an electrochemical device, a portion of the battery cell 600 is located within the receiving groove 500 (e.g., ...). Figure 10 As shown in the figure, this makes the structure of the electrochemical device more compact, thereby increasing the energy density of the battery. Furthermore, since the puncture resistance and resistivity of the second insulating layer 300 are greater than those of the molten adhesive layer 400, the reduction in insulation and puncture resistance caused by the removal of the molten adhesive layer 400 is reduced, thus ensuring the safety and service life of the electrochemical device.

[0055] It should be noted that the puncture resistance can be measured using a universal testing machine for tensile or shear tests, and the resistivity can be measured using a high-resistivity meter or a three-electrode system. Furthermore, when the encapsulation film of this embodiment is applied to the battery cell 600, it can be used individually or in pairs as needed, and different sized receiving grooves 500 can be provided to accommodate different specifications of battery cells 600. For example, taking the use of a single encapsulation film, the receiving groove 500 is located on one side of the encapsulation film. Pressure is applied to the second insulating layer 300 by a pressure head to form a recess in the encapsulation film whose bottom wall matches the shape and size of the receiving groove 500. Then, the battery cell 600 is placed into the recess, and the encapsulation film is folded in half to cover the recess on the other side. Subsequently, the molten adhesive layer 400 is melted and bonded by hot pressing. It can be understood that in the electrochemical device formed by the above process, the receiving groove 500 is located on one side of the battery cell 600 in the thickness direction, that is, one side of the battery cell 600 in the thickness direction is located within the receiving groove 500. Furthermore, to ensure that the battery cell 600 is covered by the receiving groove 500 on both sides in the thickness direction, the size of the receiving groove 500 can be appropriately increased. During the stamping process, a recess is formed only on one side of the receiving groove 500. After folding the encapsulation film, the other side of the receiving groove 500 covers the other side of the battery cell 600, thereby allowing both sides of the battery cell 600 to extend into the receiving groove 500 (e.g., Figure 10 This increases the energy density of the electrochemical device. Alternatively, as in some embodiments, the molten adhesive layer 400 has two spaced-apart receiving grooves 500 (e.g., ...). Figure 9 As shown), the first inner walls 510 of the two receiving grooves 500 are respectively used to form two wall surfaces of the receiving cavity 710 within the thickness of the encapsulation body 700. That is, the two receiving grooves 500 are respectively located on both sides of the battery cell 600, and both sides of the battery cell 600 can extend into the receiving grooves 500 (as shown). Figure 11 (As shown). Furthermore, when both encapsulation films are used together, the battery cell 600 can be sandwiched between the receiving grooves 500 of the two encapsulation films (e.g., Figure 12 As shown, the molten adhesive layer 400 is melted and connected by hot pressing, thereby forming an encapsulation structure in which both sides are covered by the receiving groove 500.

[0056] Based on the above embodiment, L2 = 0, that is, all the molten adhesive layer 400 is removed from the part corresponding to the receiving tank 500 (e.g. Figure 2(As shown), to increase the depth of the molten adhesive layer 400. Therefore, when used in an electrochemical device, the receiving tank 500 can accommodate more cells 600, thereby increasing the energy density of the electrochemical device.

[0057] In some embodiments, the molten adhesive layer 400 is connected to the metal layer 200, and the boundary of the first projection coincides with the boundary of the second projection (e.g., Figure 2 (As shown). That is, the shape and size of the second insulating layer 300 are adapted to the shape and size of the receiving groove 500, that is, the size of the second insulating layer 300 is adapted to the size of the receiving cavity 710 formed when the encapsulation film is encapsulated in the battery cell 600, so that there is no need to set too many second insulating layers 300, reducing the amount of insulating layer used, thereby reducing manufacturing costs. It should be emphasized that when L2>0, L2 is, for example, 1μm, 2μm, 3μm, 4μm, 5μm, 10μm, 15μm, 20μm, 25μm or 30μm, or within the range of any two of the above values. Thus, at the location corresponding to the receiving groove 500, the encapsulation film retains a portion of the molten adhesive layer 400 to form a double protection effect, in order to ensure the insulation of the encapsulation film and improve the stability of the structure. In addition, the retained molten adhesive layer 400 can effectively buffer external stress, prevent the second insulating layer 300 from cracking or breaking due to direct contact with the battery cell 600, and further improve the mechanical durability and environmental adaptability of the encapsulation film. When L2 = 0, the second insulating layer 300 serves as the bottom wall of the receiving groove 500. Therefore, the encapsulation film of this embodiment can be formed using commercially available common encapsulation films (such as aluminum-plastic film) as the base material. Taking aluminum-plastic film as an example, during the processing, grooves are first formed on the PP layer 1 of the aluminum-plastic film using laser processing, machining, or chemical and heat treatment, so that the aluminum layer is exposed from the grooves. Then, the second insulating layer 300 is set in the grooves, and the second insulating layer 300 completely covers the aluminum layer exposed from the grooves. This results in lower manufacturing costs, stronger process compatibility, and suitability for large-scale automated production.

[0058] In some embodiments, the first projection is located within the range of the second projection, and the boundaries of the first projection and the second projection are spaced apart (e.g., ...). Figures 6 to 8(As shown). That is, in this embodiment, a portion of the molten adhesive layer 400 covers the second insulating layer 300, thereby reducing the risk of short circuits caused by deformation of the first insulating layer 100 or the second insulating layer 300. Specifically, it is understood that the electrochemical device shrinks during use. Based on this, in this embodiment, a portion of the molten adhesive layer 400 covers the second insulating layer 300. Therefore, even if both the molten adhesive layer 400 and the second insulating layer 300 shrink during use, effective coverage between them can still be maintained, avoiding exposure of the aluminum layer due to deformation. This maintains the good insulation performance and structural integrity of the encapsulation film in this embodiment, thereby improving the safety and cycle life of the electrochemical device.

[0059] Combination Figures 10 to 11 The electrochemical device of the second aspect of this application includes any device in which an electrochemical reaction occurs to convert chemical energy into electrical energy. Specific, non-limiting examples include all types of primary batteries, secondary batteries, fuel cells, solar cells, or capacitors. In particular, the electrochemical device is a lithium secondary battery, including lithium metal secondary batteries, lithium-ion secondary batteries, lithium polymer secondary batteries, or lithium-ion polymer secondary batteries. The electrochemical device of this embodiment includes: a battery cell 600 and an encapsulation film as described in the first aspect embodiment. The battery cell 600 is, for example, a wound battery cell, a stacked battery cell, a non-circular stacked battery cell, or a 3D stacked battery cell, etc., and includes a battery cell body and tabs connected to the battery cell body. The encapsulation film covers the battery cell body and forms a receiving cavity 710, which includes a receiving groove 500, within which a portion of the battery cell body is located.

[0060] Specifically, the electrochemical device of this embodiment uses the encapsulation film of the first aspect embodiment. The encapsulation film has a receiving groove 500. In a first direction, the projection of the receiving groove 500 onto the metal layer 200 is a first projection, and the projection of the second insulating layer 300 onto the metal layer 200 is a second projection. The first projection does not protrude from the second projection. That is, the encapsulation film has a second insulating layer 300 with higher puncture resistance and resistivity at the part where the molten adhesive layer 400 is removed. The main body of the battery cell is located in the receiving cavity 710 and partly in the receiving groove 500, thereby making the structure of the electrochemical device more compact and improving the energy density of the electrochemical device. Since the puncture resistance and resistivity of the second insulating layer 300 are both greater than those of the molten adhesive layer 400, the weakening of insulation and puncture resistance caused by the removal of the molten adhesive layer 400 is reduced, thereby ensuring the safety and service life of the electrochemical device of this embodiment.

[0061] It should be noted that since this embodiment adopts all the technical features of the encapsulation film of the first aspect embodiment, the electrochemical device of this embodiment possesses all the beneficial effects brought by the first aspect embodiment, which will not be repeated here. Furthermore, it should be noted that the electrochemical device in this embodiment may include one encapsulation film, which is folded in half to form a receiving cavity 710 to cover the battery cell 600, or it may include two encapsulation films combined together to form the receiving cavity 710. Taking a common square battery as an example, the electrochemical device of this embodiment includes three sealing structures (top seal and two side seals) or four sealing structures (top seal, bottom seal, and two side seals).

[0062] The electronic device of the third aspect of this application includes the electrochemical device of the second aspect embodiment. The electronic device of this application is not particularly limited and can be any electronic device known in the prior art, including but not limited to mobile phones, smartphones, laptops, tablets, wearable devices, smartwatches, smart bracelets, smart glasses, power banks, televisions, game consoles, game controllers, digital cameras, smart speakers, headphones, keyboards, mice, monitors, drones, audio equipment, home appliances, toys, power tools, automobiles, motorcycles, electric bicycles, bicycles, robots, robot dogs, industrial robots, android robots, etc.

[0063] Specifically, the electronic device in this embodiment adopts the electrochemical device of the second aspect embodiment. The encapsulation film in the electrochemical device has a receiving groove 500. In a first direction, the projection of the receiving groove 500 on the metal layer 200 is a first projection, and the projection of the second insulating layer 300 on the metal layer 200 is a second projection. The first projection does not protrude from the second projection, that is, the encapsulation film has a second insulating layer 300 with higher puncture resistance and resistivity at the part where the molten adhesive layer 400 is removed. The main body of the battery cell is located in the receiving cavity 710 and partially in the receiving groove 500, making the structure of the electrochemical device more compact, thereby improving the energy density of the electrochemical device. Furthermore, since the puncture resistance and resistivity of the second insulating layer 300 are both greater than those of the molten adhesive layer 400, the weakening of insulation and puncture resistance caused by the removal of the molten adhesive layer 400 is reduced, thereby ensuring the safety and service life of the electrochemical device, and thus improving the service life and safety of the electronic device.

[0064] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of this application. Furthermore, in the description of this application, the reference to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., means that the specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples.

Claims

1. An encapsulation film, characterized in that, For encapsulating a battery cell to form an electrochemical device, the electrochemical device including an encapsulation body formed by the encapsulation film, the encapsulation body having a receiving cavity, the battery cell being located within the receiving cavity, the encapsulation film comprising: First insulating layer; A metal layer is attached to any surface of the first insulating layer in a first direction, wherein the first direction is the thickness direction of the first insulating layer; A second insulating layer is attached to the surface of the metal layer opposite to the first insulating layer; A molten adhesive layer is attached to the surface of the metal layer opposite to the encapsulation film and / or the surface of the second insulating layer opposite to the metal layer, wherein the resistivity of the second insulating layer is greater than the resistivity of the molten adhesive layer, and the puncture resistance of the second insulating layer is greater than the puncture resistance of the molten adhesive layer; and... The surface of the encapsulation film facing away from the first insulating layer also has a receiving groove, the receiving groove having a first inner wall in the thickness direction of the encapsulation film, and in the first direction, the distance between the first inner wall and the surface of the metal layer facing the second insulating layer is L1, L1>0; In the first direction, the projection of the receiving groove onto the metal layer is the first projection, and the projection of the second insulating layer onto the metal layer is the second projection. The first projection does not protrude beyond the second projection.

2. The encapsulation film according to claim 1, characterized in that, In the first direction, the distance between the surface of the second insulating layer facing away from the metal layer and the first inner wall is L2, where L2≥0.

3. The encapsulation film according to claim 2, characterized in that, The first projection is located within the range of the second projection, and the boundaries of the first projection and the second projection are spaced apart.

4. The encapsulation film according to claim 3, characterized in that, The molten adhesive layer is attached to the surface of the second insulating layer opposite to the metal layer. In the first direction, the projection of the molten adhesive layer onto the metal layer is a third projection, which does not protrude from the second projection.

5. The encapsulation film according to claim 3, characterized in that, The second projection is spaced apart from the edge of the metal layer.

6. The encapsulation film according to claim 1, characterized in that, The molten adhesive layer is connected to the metal layer, and the boundary of the first projection coincides with the boundary of the second projection.

7. The encapsulation film according to claim 1, characterized in that, The molten adhesive layer has two spaced-apart receiving grooves, and the first inner walls of the two receiving grooves are respectively used to form two side walls of the receiving cavity in the thickness direction of the encapsulation body.

8. The encapsulation film according to any one of claims 1 to 7, characterized in that, The second insulating layer is formed using a mixture of ceramic and polytetrafluoroethylene.

9. An electrochemical device, characterized in that, include: A battery cell includes a cell body and tabs connected to the cell body; The encapsulation film according to any one of claims 1 to 8, wherein the encapsulation film covers the battery cell body and forms a receiving cavity, the receiving cavity including the receiving groove, and a portion of the battery cell body is located within the receiving groove.

10. An electronic device, characterized in that, Includes the electrochemical device as described in claim 8 or 9.

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