Electrochemical device and electronic apparatus

Abstract

The application discloses an electrochemical device and an electronic device, wherein the electrochemical device comprises a packaging bag and an electric core. The packaging bag comprises a packaging body and a plurality of edge sealing structures, the packaging body has a containing cavity, and the electric core comprises an electric core body, which is located in the containing cavity. The edge sealing structure is connected to the packaging body, and the edge sealing structure has a melt adhesive layer. The plurality of edge sealing structures comprises a first edge sealing structure, the melt adhesive layer of the first edge sealing structure is defined as a first melt adhesive layer, the first melt adhesive layer comprises a first melt adhesive part and a plurality of second melt adhesive parts, the first melt adhesive part and the second melt adhesive parts define a first pressure relief groove, the first pressure relief groove is communicated with the containing cavity, and the surface of the second melt adhesive part, which is away from the first melt adhesive part, is a smooth arc surface. The second melt adhesive part reduces the obstruction to the flow of gas, so that when the electrochemical device is abnormally high in temperature and inflates, the gas can be quickly guided to the first pressure relief groove to form a pressure concentration point and more easily break the edge sealing structure to release pressure, thereby reducing the risk of thermal runaway.

Description

Technical Field

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

[0002] In some technologies, when a pouch battery generates a large amount of heat due to abnormal operation, it mainly releases pressure by breaking open the sealing structure. However, in practice, it has been found that when the sealing structure is broken open, the internal air pressure of the pouch battery is already too high, which can easily lead to an explosion or the formation of a high-temperature jet of air, thus causing the risk of thermal runaway. 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 electrochemical device capable of reducing the risk of thermal runaway.

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

[0005] An electrochemical device according to a first aspect of this application includes: a packaging bag and a battery cell.

[0006] The packaging bag includes a packaging body and multiple sealing structures. The packaging body has a receiving cavity. The sealing structures are connected to the packaging body and have a molten adhesive layer formed by hot-melt bonding. Among the multiple sealing structures, there is a first sealing structure. The molten adhesive layer of the first sealing structure is defined as the first molten adhesive layer. The first molten adhesive layer includes a first molten adhesive portion and multiple second molten adhesive portions. The first molten adhesive portion is an elongated strip structure extending in a first direction, which is the length direction of the first sealing structure. In a second direction, the second molten adhesive portions are connected to the side of the first molten adhesive portion facing closer to the packaging body. The surface of the second molten adhesive portion facing away from the first molten adhesive portion is a smooth arc surface, and the arc surface extends to the first molten adhesive portion. The second direction is the width direction of the first sealing structure. The multiple second molten adhesive portions are spaced apart along the second direction. Adjacent second molten adhesive portions and the first molten adhesive portion define a first pressure relief groove, which communicates with the receiving cavity. The battery cell includes a battery cell body, which is located within the receiving cavity.

[0007] The electrochemical device according to the embodiments of this application has at least the following beneficial effects: In this embodiment, the side of the second molten adhesive portion facing away from the first molten adhesive portion is a smooth arc surface, which can reduce the obstruction of the second molten adhesive portion to gas flow. Therefore, when the electrochemical device is abnormally hot and expands, the gas can be quickly guided to the first pressure relief groove through the smooth arc surface, so that the first pressure relief groove of the first sealing structure quickly forms a pressure concentration point, thereby making the first pressure relief groove preferentially open and achieving rapid pressure relief. This avoids excessive gas pressure inside the electrochemical device and reduces the risk of thermal runaway.

[0008] According to some embodiments of this application, the second melt portion is a semi-cylindrical structure, and the arc surface is a semi-cylindrical surface.

[0009] According to some embodiments of this application, the battery cell further includes a tab connected to the battery cell body and extending from the receiving cavity from the first sealing structure.

[0010] According to some embodiments of this application, the side of the first melt portion facing the second melt portion has a second pressure relief groove, the second pressure relief groove is located between adjacent second melt portions, and the second pressure relief groove is a V-shaped groove.

[0011] According to some embodiments of this application, the edge of the second pressure relief groove is connected to the arc surface.

[0012] According to some embodiments of this application, in the first direction, the minimum distance between adjacent second molten portions is a, the radius of the second molten portion is b, and in the second direction, the size of the first molten portion is c, wherein 0≤a≤1mm, 0.14mm≤b≤0.6mm, and 0.8mm≤c≤1.12mm.

[0013] According to some embodiments of this application, 0.2 < c × (b - 0.84) × (a - 2) < 1.3.

[0014] According to some embodiments of this application, the sealing structure includes two sealing layers distributed along its own thickness direction, and each of the two sealing layers has a sub-molded adhesive layer on one side facing each other. The first sealing structure includes a sealing area and an unsealed area distributed along a second direction. The unsealed area is connected between the encapsulation body and the sealing area. The two sub-molded adhesive layers of the sealing area are fused together to form the molded adhesive layer. The two sub-molded adhesive layers of the unsealed area are separately disposed.

[0015] According to some embodiments of this application, the outer surface of the sealing structure also has a first mark, which is configured such that a second mark on the hot press head is aligned with the first mark during heat sealing, so that the edge of the hot press head is aligned with the edge of the first molten adhesive layer.

[0016] An electronic device according to a second aspect of this application includes the electrochemical device described in the first aspect.

[0017] The electronic device according to the embodiments of this application has at least the following beneficial effects: In the electrochemical device of the first aspect embodiment, the side of the second molten part facing away from the first molten part is a smooth arc surface, which can reduce the obstruction of the second molten part to gas flow. Therefore, when the inside of the electrochemical device is abnormally hot and expands with gas, the gas can be quickly guided to the first pressure relief groove through the smooth arc surface, so that the first pressure relief groove of the first sealing structure quickly forms a pressure concentration point, thereby causing the first pressure relief groove to be preferentially opened, realizing rapid pressure relief. This avoids excessive gas pressure inside the electrochemical device, reduces the risk of thermal runaway, and improves the safety of the electronic device of this embodiment.

[0018] 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

[0019] The present application will be further described below with reference to the accompanying drawings and embodiments, wherein: Figure 1 This is a schematic diagram of the structure of a first electrochemical device according to the first aspect of this application; Figure 2 for Figure 1 A sectional view; Figure 3 for Figure 2 Enlarged view of part A in the middle; Figure 4 for Figure 1 A schematic diagram of the structure of the electrochemical device in another state; Figure 5 This is a partial cross-sectional view of the second electrochemical device according to the first aspect of this application; Figure 6 This is a partial cross-sectional view of the third electrochemical device according to the first aspect of this application; Figure 7 for Figure 6 A diagram showing the unsealed area after it was opened.

[0020] Figure label: The package includes a packaging bag 100, a packaging body 110, a receiving cavity 111, a sealing structure 120, a sealing area 1201, an unsealed area 1202, a sub-sealing portion 1203, a sub-molded adhesive layer 1213, and a melt adhesive layer 121. The first edge sealing structure 10, the first molten adhesive layer 11, the first molten adhesive section 1101, the second molten adhesive section 1102, the first pressure relief groove 1103, and the second pressure relief groove 1104. Detailed Implementation

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] In some technologies, when a pouch battery generates a large amount of heat due to abnormal operation, it mainly releases pressure by expanding the sealing structure through internal air pressure. However, in practice, it has been found that when the sealing structure is broken open, the internal air pressure of the pouch battery is already too high, which can easily lead to an explosion or the formation of a high-temperature jet of air, thus causing the risk of thermal runaway.

[0026] In view of the above background, this application proposes an electrochemical device capable of reducing the risk of thermal runaway. The electrochemical device includes all types of primary and secondary batteries; 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. Combined with Figures 1 to 7 The specific embodiments of this application will be explained, wherein... Figures 2 to 7 The center line in the diagram should not be interpreted as the actual outline of the electrochemical device, but is only used to clearly show the boundary between the sealed area 1201 and the unsealed area 1202. The electrochemical device in this embodiment includes a packaging bag 100 and a battery cell.

[0027] The packaging bag 100 is made of packaging film such as aluminum-plastic film, steel-plastic film, or composite film. The packaging bag 100 includes a packaging body 110 and multiple sealing structures 120. The packaging body 110 has a receiving cavity 111. The battery cell is, for example, a wound battery cell or a stacked battery cell. The battery cell includes a battery cell body, which is located within the receiving cavity 111. The sealing structures 120 are connected to the packaging body 110 and have a molten adhesive layer 121 formed by hot-melt bonding. Among the multiple sealing structures 120, there is a first sealing structure 10. The molten adhesive layer 121 of the first sealing structure 10 is defined as the first molten adhesive layer 11. In a first direction (the first direction is the length direction of the first sealing structure 10), the first molten adhesive layer 11 includes a first molten adhesive portion 1101 and multiple second molten adhesive portions 1102. The first molten adhesive portion 1101 is an elongated strip structure extending along the first direction. In the second direction (the second direction being the width direction of the first sealing structure 10), the second molten adhesive portion 1102 is connected to the side of the first molten adhesive portion 1101 facing closer to the encapsulation body 110. The surface of the second molten adhesive portion 1102 facing away from the first molten adhesive portion 1101 is a smooth arc surface such as a semi-cylindrical surface or a semi-elliptical surface, and the arc surface extends to the first molten adhesive portion 1101, that is, the arc surface intersects with the side of the first molten adhesive portion 1101 facing the second molten adhesive portion 1102. A plurality of second molten adhesive portions 1102 are distributed at intervals along the second direction to form a first pressure relief groove 1103, which communicates with the receiving cavity 111.

[0028] Taking a square soft-pack battery as an example, the packaging bag 100 includes four sealing structures 120 or three sealing structures 120. Specifically, the packaging bag 100 is formed by heat-sealing a single packaging film by folding it in half, forming a top sealing edge and two side sealing edges, or by heat-sealing two packaging films together to form a top sealing edge, a bottom sealing edge, and two side sealing edges. One or two of the top sealing edge, bottom sealing edge, and side sealing edges serve as the first sealing edge structure 10. Taking the top sealing edge as the first sealing edge structure 10 and the packaging film as an aluminum-plastic film as an example, during the processing, before heat sealing, the PP layer is partially removed from the aluminum-plastic film at the position corresponding to the top sealing edge by laser processing or machining, forming a groove that matches the position and shape of the second molten adhesive portion 1102. During heat sealing, the aluminum-plastic film is hot-pressed by a hot press head that corresponds to the shape and size of the molten adhesive layer 121, so that the PP layer is fused to form a molten adhesive layer 121 with a first pressure relief groove 1103.

[0029] Specifically, in this embodiment, the side of the second molten adhesive portion 1102 facing away from the first molten adhesive portion 1101 is a smooth arc surface, which reduces the obstruction of gas flow by the second molten adhesive portion 1102. Therefore, when the electrochemical device experiences abnormally high temperatures and gas expansion, the gas can be quickly guided to the first pressure relief groove 1103 through the smooth arc surface, causing a pressure concentration point to quickly form at the first pressure relief groove 1103 of the first sealing structure 10. This allows the first pressure relief groove 1103 to be preferentially opened, achieving rapid pressure relief and thus preventing excessive gas pressure inside the electrochemical device, thereby reducing the risk of thermal runaway. It is also known that the width of the molten adhesive layer 121 at the first pressure relief groove 1103 (the dimension along the second direction) is smaller than the width of the region, making it more prone to rupture under gas pressure, thus achieving directional pressure relief of the electrochemical device. Simultaneously, this design can be combined with the internal pressure relief channel of the electronic device to effectively guide the gas out in a directional manner, avoiding structural damage or safety accidents caused by disordered release of internal pressure. Furthermore, it is understood that during the processing, a hot press head that matches the shape of the second melt part 1102 is also required for hot pressing. In this embodiment, the second melt part 1102 is an arc surface, and the corresponding hot press head has a matching arc surface. Compared with a hot press head with sharp edges, the arc surface design can effectively reduce stress concentration, prevent the encapsulation film from being damaged due to excessive local stress during the heat sealing process, improve the sealing yield and structural reliability, and the arc surface is easier to process, reducing the processing cost of the hot press head.

[0030] Reference Figure 3 In some embodiments, the second molten adhesive portion 1102 is a semi-cylindrical structure with a semi-cylindrical arc surface, that is, the arc surface intersects perpendicularly with the side surface of the first molten adhesive portion 1101. Therefore, when the gas flows along the arc surface to contact the first molten adhesive portion 1101, the first molten adhesive portion 1101 is subjected to a vertical impact, thereby subjecting the first molten adhesive portion 1101 to greater pressure. This allows the first sealing structure 10 to be easily broken at that point, achieving rapid pressure release and reducing the risk of thermal runaway of the electrochemical device.

[0031] Reference Figure 4In some embodiments, the cell 200 further includes tabs 220, which are connected to the cell body 210 and extend from the receiving cavity 111 from the first sealing structure 10. Specifically, in order to improve the energy density of the electrochemical device, the sealing structure 120 is usually folded towards the encapsulation body 110 to reduce the volume of the electrochemical device. However, for the sealing structure 120 with tabs 220, since the electrochemical device is externally provided with a PCB board for connecting to the tabs 220, the PCB board can be disposed on the surface of the sealing structure 120, so that the space occupied by the sealing structure 120 and the PCB board overlaps, which has little impact on the energy density of the electrochemical device, and there is no need to fold the sealing structure 120 towards the encapsulation body 110. To explain more clearly, take a square pouch battery as an example. The pouch battery has a set length and width, the top sealing edge is located on one side of the length of the pouch battery, and the side sealing edges of the pouch battery are folded towards the sealing body (e.g., Figure 4 As shown, the top sealing edge is not folded towards the packaging body 110. The PCB board is set on the top sealing edge and connected to the tab 220. The space occupied by the top sealing edge and the PCB board in the length direction of the soft pack battery coincides. Therefore, the top sealing edge will not increase the length of the soft pack battery. And because the thickness of the top sealing edge is small, its impact on the thickness of the soft pack battery is small. Therefore, even if the top sealing edge is not folded towards the packaging body 110, its impact on the overall energy density is small.

[0032] Based on this, in this embodiment, the tab 220 extends from the first sealing structure 10, that is, the electrochemical device of this embodiment is used in electronic devices. The first sealing structure 10 does not need to be folded towards the encapsulation body 110, so that the first pressure relief groove 1103 is aligned with the receiving cavity 111. Therefore, when the gas pressure inside the receiving cavity 111 rises abnormally, the gas can flow more smoothly to the first pressure relief groove 1103, so that the first pressure relief groove 1103 can respond to the pressure relief demand more quickly, thereby triggering the rupture of the first pressure relief groove 1103 more efficiently when the internal pressure increases sharply, reducing the risk of thermal runaway of the electrochemical device.

[0033] Reference Figure 5In some embodiments, the first melt section 1101 has a second pressure relief groove 1104 on the side facing the second melt section 1102. The second pressure relief groove 1104 is located between adjacent second melt sections 1102 and is a V-shaped groove. Therefore, during the expansion process, the gas will quickly enter the first pressure relief groove 1103 and then enter the narrower second pressure relief groove 1104 through the first pressure relief groove 1103 and be compressed. This causes the gas to accumulate higher pressure in the second pressure relief groove 1104, making the first sealing structure 10 easier to break open, thereby accelerating the rupture process, achieving faster pressure relief, and further reducing the risk of thermal runaway. In addition, since the second pressure relief groove 1104 in this embodiment is a V-shaped groove, its tip structure can further concentrate stress, causing the sealing material to tear preferentially along the bottom of the V-shaped groove under the action of high-pressure gas. This can further improve the reliability and response speed of pressure relief, ensuring that energy can be released in time when the internal pressure of the electrochemical device rises abnormally, thereby reducing the safety hazards caused by thermal runaway.

[0034] Reference Figure 5 Based on the above embodiment, the edge of the second pressure relief groove 1104 is connected to an arc surface, which reduces the flow resistance between the first pressure relief groove 1103 and the second pressure relief groove 1104 when the gas enters the second pressure relief groove 1104 through the first pressure relief groove 1103. This allows the energy of the gas to be more concentrated on the stress tip of the second pressure relief groove 1104, making it easier for the first sealing structure 10 to rupture at the tip of the V-shaped groove, further reducing the risk of thermal runaway of the electrochemical device in this embodiment.

[0035] Reference Figure 3In some embodiments, in the first direction, the minimum distance between adjacent second molten adhesive portions 1102 is 'a', and the radius of the second molten adhesive portion 1102 is 'b'. In the second direction, the dimension of the first molten adhesive portion 1101 is 'c', where 0 ≤ a ≤ 1 mm, 0.14 mm ≤ b ≤ 0.6 mm, and 0.8 mm ≤ c ≤ 1.12 mm. Specifically, the minimum distance 'a' between adjacent second molten adhesive portions 1102 is, for example, 0, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, or 1 mm, or falls within the range of any two of the above values. The radius b of the second molten adhesive portion 1102 is, for example, 0.14 mm, 0.15 mm, 0.16 mm, 0.17 mm, 0.18 mm, 0.19 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, or 0.6 mm, or falls within the range of any two of the aforementioned values. The dimension c of the first molten adhesive portion 1101 is, for example, 0.8 mm, 0.85 mm, 0.9 mm, 0.95 mm, 1.0 mm, 1.1 mm, or 1.12 mm, or falls within the range of any two of the aforementioned values.

[0036] Specifically, the distance between adjacent second molten adhesive portions 1102 determines the distance of the first pressure relief groove 1103 in the first direction, which in turn determines the pressure-bearing area of ​​the first molten adhesive portion 1101 when impacted, thus affecting the trigger pressure threshold for the rupture of the first sealing structure 10. The radius of the second molten adhesive portion 1102 determines the size of the first pressure relief groove 1103 in the second direction. Within the limited space of the first sealing structure 10, the larger the size of the first pressure relief groove 1103, the smaller the size of the first molten adhesive portion 1101, thus affecting the overall strength of the first sealing structure 10. If the size of the first pressure relief groove 1103 is too large, the width reduction of the molten adhesive layer 121 will be smaller, making the first sealing structure 10 difficult to break through and unable to form effective stress concentration within the second pressure relief groove 1104, thereby affecting the pressure relief response speed. Based on this, in this embodiment, the distance between adjacent second melt portions 1102, the radius of the second melt portion 1102, and the width of the first melt portion 1101 are set within a reasonable range to ensure that the first sealing structure 10 maintains reliable sealing under normal working pressure, while responding quickly to rupture under abnormal high pressure.

[0037] Based on the above embodiment, 0.2 < c × (b - 0.84) × (a - 2) < 1.3 to ensure that the first sealing structure 10 maintains reliable sealing under normal working pressure, while responding quickly to rupture under abnormal high pressure. Specifically, to verify the above effect, the following experiment was conducted: the electrochemical device was placed in a hot box, heated from 25°C to a specified temperature and maintained at that temperature for 1 hour. The hot box was then opened to observe whether the electrochemical device ignited. If an explosion did not ignite, the highest temperature of the hot box set point was recorded. The experimental results are as follows:

[0038] The comparative example is a conventional battery hot box passing test, with a hot box passing temperature of 120℃. As shown in Example 7 above, when c×(b-0.84)×(a-2)<0.2, the electrochemical device leaks. When 1.3<c×(b-0.84)×(a-2), the hot box passing temperature is 120℃, which is the same as the conventional structure hot box passing temperature. That is, when 1.3<c×(b-0.84)×(a-2), there is no significant improvement in hot box passing. This proves that when c×(b-0.84)×(a-2) is in the range of 0.2 to 1.3, the first sealing structure 10 can achieve controllable rupture under abnormal high temperature or pressure while ensuring normal sealing performance, effectively releasing internal stress and preventing the electrochemical device from catching fire or exploding.

[0039] Reference Figure 6 and Figure 7 In some embodiments, the sealing structure 120 includes two sealing portions distributed along its own thickness direction. Each of the two sealing portions has a sub-melt adhesive layer 1213 on one side facing each other. The first sealing structure 10 includes a sealing area 1201 and an unsealed area 1202 distributed along a second direction. The unsealed area 1202 is connected between the encapsulation body 110 and the sealing area 1201. The two sub-melt adhesive layers 1213 of the sealing area 1201 are fused together to form a melt adhesive layer 121. The two sub-melt adhesive layers 1213 of the unsealed area 1202 are separately disposed. For example, the packaging bag 100 is formed by processing aluminum-plastic film. The sealing part includes a nylon layer, an aluminum layer and a PP layer connected in sequence along the thickness direction. That is, the sub-melt layer 1213 is a PP layer. The PP layers located in the sealing area 1201 are fused together to form the melt layer 121. The PP layers located in the unsealed area 1202 are not fused. That is, the PP in the unsealed area 1202 is a separate structure. When the interior of the receiving cavity 111 increases, the PP layer in the unsealed area 1202 can open.

[0040] It is understandable that the battery generates heat during normal operation, which increases the internal pressure. In this embodiment, the unsealed area 1202 provides a buffer space when the sealing edge expands due to heat, effectively preventing malfunctions caused by normal thermal expansion in the electrochemical device. However, when the electrochemical device experiences an abnormal temperature rise or a sudden increase in internal pressure, the sub-melt layer 1213 of the unsealed area 1202 is not fused, causing it to rapidly open into a ">" shape (e.g., ...). Figure 7 As shown), the ">" shape can guide the airflow, and the end of the ">" is connected to the sealing area 1201, so that the gas can quickly converge towards the first pressure relief groove 1103 of the sealing area 1201, causing the first sealing structure 10 to break more quickly at the first pressure relief groove 1103, further increasing the pressure relief rate and reducing the risk of thermal runaway of the electrochemical device.

[0041] In some embodiments, the outer surface of the sealing structure 120 also has a first mark, which is configured such that a second mark on the hot press head aligns with the first mark during heat sealing, so that the edge of the hot press head aligns with the edge of the first molten adhesive layer 11. Specifically, the first mark is, for example, a recessed structure, a raised structure, or a silkscreen mark, and the corresponding second mark is set as a mark on the hot press head, such as a raised or recessed structure or a silkscreen mark, to ensure that the hot press head and the sealing edge are accurately aligned during the heat sealing process, and to ensure that the formation position of the first pressure relief groove 1103 in this embodiment is accurate, thereby ensuring the reliability of the pressure relief function and the structural consistency of the electrochemical device in this embodiment, effectively improving the product yield and safety of the electrochemical device in this embodiment.

[0042] The electronic device of the second aspect of this application includes the electrochemical device of the first aspect embodiment. The side of the second molten adhesive portion 1102 in the electrochemical device facing away from the first molten adhesive portion 1101 is a smooth arc surface, which can reduce the obstruction of the second molten adhesive portion 1102 to the gas flow. Therefore, when the inside of the electrochemical device is abnormally hot and expands, the gas can be quickly guided to the first pressure relief groove 1103 through the smooth arc surface, so that the first pressure relief groove 1103 of the first sealing structure 10 quickly forms a pressure concentration point, thereby making the first pressure relief groove 1103 preferentially open and realizing rapid pressure relief. This avoids excessive gas pressure inside the electrochemical device, reduces the risk of thermal runaway, and improves the safety of the electronic device of this embodiment.

[0043] It should be noted that the electronic device in this application is not particularly limited, and can be any electronic device known in the prior art. The electrochemical device in this application is not particularly limited in its use, and can be used in any electronic device known in the prior art. According to some embodiments of this application, the electronic device includes, but is 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, robotic dogs, industrial robots, and androids. Since the electronic device in this embodiment adopts all the technical features of the first aspect embodiment, this embodiment possesses all the beneficial effects brought by the first aspect embodiment, which will not be repeated here.

[0044] 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 electrochemical device, characterized in that, include: A packaging bag includes a packaging body and multiple sealing structures. The packaging body has a receiving cavity. The sealing structures are connected to the packaging body and have a molten adhesive layer formed by hot-melt bonding. Among the multiple sealing structures, there is a first sealing structure. The molten adhesive layer of the first sealing structure is defined as the first molten adhesive layer. In a first direction, the first molten adhesive layer includes a first molten adhesive portion and multiple second molten adhesive portions. The first molten adhesive portion is an elongated strip structure extending along a first direction, which is the length direction of the first sealing structure. In a second direction, the second molten adhesive portions are connected to the side of the first molten adhesive portion close to the packaging body. The surface of the second molten adhesive portion facing away from the first molten adhesive portion is a smooth arc surface, and the arc surface extends to the first molten adhesive portion. The second direction is the width direction of the first sealing structure. The multiple second molten adhesive portions are spaced apart along the second direction. Adjacent second molten adhesive portions and the first molten adhesive portion define a first pressure relief groove, which is connected to the receiving cavity. A battery cell, including a battery cell body, wherein the battery cell body is located within the receiving cavity.

2. The electrochemical device according to claim 1, characterized in that, The second melt section has a semi-cylindrical structure, and the arc surface is a semi-cylindrical surface.

3. The electrochemical device according to claim 1, characterized in that, The battery cell also includes a tab, which is connected to the battery cell body and extends out of the receiving cavity from the first sealing structure.

4. The electrochemical device according to claim 1, characterized in that, The first melt section has a second pressure relief groove on the side facing the second melt section. The second pressure relief groove is located between adjacent second melt sections and is a V-shaped groove.

5. The electrochemical device according to claim 4, characterized in that, The edge of the second pressure relief groove is connected to the arc surface.

6. The electrochemical device according to claim 2, characterized in that, In the first direction, the minimum distance between adjacent second molten sections is a, the radius of the second molten section is b, and in the second direction, the size of the first molten section is c, where 0≤a≤1mm, 0.14mm≤b≤0.6mm, and 0.8mm≤c≤1.12mm.

7. The electrochemical device according to claim 6, characterized in that, 0.2<c×(b-0.84)×(a-2)<1.

3.

8. The electrochemical device according to claim 1, characterized in that, The sealing structure includes two sealing layers distributed along its own thickness direction. Each of the two sealing layers has a sub-molded adhesive layer on one side facing each other. The first sealing structure includes a sealing area and an unsealed area distributed along a second direction. The unsealed area is connected between the encapsulation body and the sealing area. The two sub-molded adhesive layers located in the sealing area are fused together to form the molded adhesive layer. The two sub-molded adhesive layers located in the unsealed area are separately arranged.

9. The electrochemical device according to claim 1, characterized in that, The outer surface of the sealing structure also has a first mark, which is configured such that a second mark on the hot press head is aligned with the first mark during heat sealing, so that the edge of the hot press head is aligned with the edge of the first molten adhesive layer.

10. An electronic device, characterized in that, The electrochemical device includes any one of claims 1 to 9.

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