Secondary battery and electronic device

Abstract

Disclosed in the present application are a secondary battery and an electronic device. The secondary battery comprises an electrode assembly, a pouch and an insulating adhesive, wherein the pouch comprises a main body portion and a first side sealed edge. The main body portion accommodates the electrode assembly, and comprises a first side wall and a second side wall, which are arranged in the direction of thickness of the secondary battery. The first side sealed edge comprises a first connection portion and a second connection portion, which are arranged in sequence, wherein the first connection portion is connected to the main body portion; the second connection portion is bent towards the main body portion relative to the first connection portion; and an included angle θ is formed between the first connection portion and the first side wall, and meets 0°＜θ＜90°. The thickness of the main body portion is smaller than the width of the first connection portion; and the insulating adhesive covers the end of the second connection portion that faces the main body portion, and the insulating adhesive bonds the first connection portion to the second connection portion, and also bonds the second connection portion to the main body portion. The secondary battery of the present application is conductive to improving energy density, and is conductive to reducing the risk of deformation of the first side sealed edge while the end of the second connection portion is sealed.

Description

Secondary battery and electronic device Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to a secondary battery and an electronic device. Background Art

[0002] The trend toward thinner and lighter electronic products has also led to higher requirements for the size of secondary batteries. The desire to make secondary batteries as thin as possible has led to the development of ultra-thin secondary batteries. However, the folding process used for conventional secondary batteries is not suitable for ultra-thin secondary batteries. The folding edge of an ultra-thin secondary battery is longer than the thickness of the battery body. If the folding process is performed, the folding edge will extend beyond the battery body in the thickness direction, thus affecting the overall thickness of the secondary battery.

[0003] Currently, ultra-thin secondary batteries typically do not have folded edges. Instead, glue is applied to the ends of the edge seal to cover the aluminum layer of the aluminum-plastic film packaging, preventing exposure. This flat edge seal design occupies space in the width direction of the secondary battery, reducing energy density. Furthermore, the exposed glue layer on the edge seal may cause the glue to fall off and leak aluminum. Summary of the Invention

[0004] In view of this, the present application provides a secondary battery and an electronic device, aiming to improve the energy density of the secondary battery and reduce the risk of aluminum layer exposure.

[0005] In a first aspect, the present application provides a secondary battery comprising an electrode assembly, a packaging bag, and insulating adhesive, wherein the packaging bag comprises a main body and a sealing portion. A receiving cavity is provided within the main body to accommodate the electrode assembly. The main body comprises a first side wall and a second side wall disposed opposite each other along a first direction, wherein the first direction is the thickness direction of the secondary battery. The sealing portion is connected to the main body and seals the receiving cavity. The sealing portion comprises a first side seal, which is disposed on one side of the main body in a second direction perpendicular to the first direction. The first side seal comprises a first connecting portion and a second connecting portion disposed sequentially. The first connecting portion is connected to the main body, and the second connecting portion is bent toward the main body relative to the first connecting portion. An angle θ is formed between the first connecting portion and the first side wall, satisfying 0°<θ<90°. The thickness of the main body along the first direction is H. The width of the first connecting portion along the direction extending from the end of the first connecting portion connected to the main body to the end of the first connecting portion away from the main body is T1, satisfying H<T1. The insulating glue covers one end of the second connection part facing the main body, the insulating glue adheres the first connection part and the second connection part, and the insulating glue also adheres the second connection part and the main body.

[0006] The first connecting portion is angled with the first side wall, so that the first side seal is arranged at an angle to the first side wall as a whole, reducing the space occupied by the first side seal. Compared with the solution of laying the seal flat, it is beneficial to reduce the width of the secondary battery in the second direction, and compared with the folded edge solution, it is beneficial to reduce the thickness of the secondary battery in the first direction, thereby facilitating the improvement of the energy density of the secondary battery. The insulating glue covers the end of the second connecting portion facing the main body, so that the aluminum layer of the end of the second connecting portion facing the main body is not exposed, and the insulating glue is located on the inside, reducing the risk of the glue falling off. The insulating glue connects the first connecting portion and the second connecting portion, and the insulating glue also connects the second connecting portion and the main body, which is beneficial to maintaining the shape of the angle between the first side seal and the first side wall, and is also beneficial to reducing the risk of deformation of the first connecting portion and the second connecting portion.

[0007] In one or more of the above embodiments, the main body further includes a third side wall and a fourth side wall arranged opposite to each other along the second direction, and the first side seal is connected to the third side wall. The insulating adhesive includes a first part and a second part, the first part is arranged between the first connecting part and the second connecting part, and the first part is bonded to the first connecting part and the second connecting part. At least part of the second part is arranged between the second connecting part and the third side wall, and the second part is bonded to the second connecting part and the third side wall. Along the extension direction from the end where the first connecting part is connected to the main body to the end of the first connecting part away from the main body, the height of the first part is D1, and along the first direction, the height of the second part is D2, satisfying 0<D1<T1, and 0<D2<H.

[0008] In the above embodiment, when D1 and D2 satisfy the condition of 0<D1<T1 and 0<D2<H, it is beneficial to improve the overall structural strength of the first side edge seal, improve the tightness of the fit between the first connecting portion and the second connecting portion, and maintain the shape of the angle between the first side edge seal and the first side wall, which is beneficial to reduce the risk of the insulating glue overflowing from the main body.

[0009] In one or more of the above embodiments, D1≤0.7T1, and D2≤0.4H are satisfied.

[0010] In the above embodiment, when D1 and D2 satisfy the conditions of D1 ≤ 0.7T1 and D2 ≤ 0.4H, this not only helps maintain the angle between the first side seal and the first side wall, but also helps save on insulating adhesive and reduce costs. It also helps reduce the risk of the first side seal opening due to excessive weight at the end away from the first side wall, and the risk of insulating adhesive overflow and resulting in poor appearance. Furthermore, it also reduces the risk of cracking the third side wall due to a drop after the insulating adhesive has cured.

[0011] In one or more of the above embodiments, 0.5 mm ≤ H < 1.5 mm, and 1.5 mm ≤ T1 ≤ 3 mm, satisfying D1 ≥ 0.5 mm.

[0012] In the above embodiment, when H is in the range of 0.5 mm ≤ H < 1.5 mm, the secondary battery is an ultra-thin secondary battery. When D1 ≥ 0.5 mm is satisfied, it is beneficial to further improve the overall structural strength of the first side edge seal and further improve the tightness of the fit between the first connecting portion and the second connecting portion.

[0013] In one or more of the above embodiments, 0.5 mm ≤ H < 1.5 mm, and 1.5 mm ≤ T1 ≤ 3 mm, satisfying 0.3 mm ≤ D2 ≤ 0.5 mm.

[0014] In the above embodiment, when H is in the range of 0.5mm≤H<1.5mm, the secondary battery is an ultra-thin secondary battery. When the condition of 0.3mm≤D2≤0.5mm is met, it is beneficial to maintain the shape of the angle between the first side seal and the first side wall, and is also beneficial to reduce the risk of the insulating glue overflowing from the main body.

[0015] In one or more of the above embodiments, along the third direction, the connection length between the main body and the first connection portion is L1, and the length of the insulating adhesive is L2, satisfying 4L1 / 5≤L2≤L1. The first direction, the second direction, and the third direction are perpendicular to each other.

[0016] In the above embodiment, when 4L1 / 5≤L2≤L1 is satisfied, it is beneficial to improve the bonding effect of the insulating adhesive and to maintain the angle between the first side seal and the first side wall.

[0017] In one or more of the above embodiments, along the extension direction from one end of the second connection portion close to the main body to one end of the second connection portion away from the main body, the width of the second connection portion is T2, satisfying 0mm<|T2-T1|≤0.5mm.

[0018] In the above embodiment, when 0mm<|T2-T1|≤0.5mm is satisfied, on the one hand, the width of the second connection part is made smaller than the width of the first connection part, which is conducive to reserving space between the end of the second connection part facing the main body and the end connected to the first connection part and the main body. The reserved space can accommodate the insulating glue, which is conducive to allowing the insulating glue to cover the end of the second connection part facing the main body. The reserved space can also allow the insulating glue in a fluid state to pass through, which is conducive to allowing the insulating glue to flow between the first connection part and the second connection part. On the other hand, the distance from the end of the second connection part facing the main body to the end connected to the first connection part and the main body will not be too large, so that the height of the insulating glue between the second connection part and the third side wall in the first direction will not be too high, which is conducive to reducing the use of insulating glue, playing a role in weight reduction, and helping to improve the energy density of the secondary battery and reduce costs.

[0019] In one or more of the above embodiments, 25°≤θ≤75° is satisfied.

[0020] In the above embodiment, when θ satisfies the above relationship, it is beneficial to further reduce the overall occupied space of the secondary battery, thereby further improving the energy density of the secondary battery.

[0021] In one or more of the above embodiments, along the second direction, an orthographic projection of the first side seal is located between the first side wall and the second side wall.

[0022] In the above embodiment, the orthographic projection of the first side seal is located between the plane where the first side wall is located and the plane where the second side wall is located, so that the first side seal does not exceed the first side wall and the second side wall in the first direction, so that the thickness of the secondary battery in the first direction is not affected by the first side seal, which is beneficial to reducing the overall thickness of the secondary battery.

[0023] In one or more of the above embodiments, along the first direction, the end of the first connecting portion connected to the main body is closer to the first side wall than to the second side wall.

[0024] In the above embodiment, along the first direction, the end of the first connecting portion connected to the main body is closer to the first side wall than the second side wall, which can fully utilize the space occupied by the secondary battery in the first direction, thereby facilitating improvement of the utilization rate of the space occupied by the secondary battery.

[0025] In one or more of the above embodiments, the main body further includes a third side wall and a fourth side wall arranged opposite to each other along the second direction, and the first connecting portion is connected to the third side wall and the first side wall respectively.

[0026] In the above embodiment, the first connection portion is connected to the third side wall and the first side wall respectively, which can more fully utilize the space occupied by the secondary battery in the first direction, thereby facilitating further improving the utilization rate of the space occupied by the secondary battery.

[0027] In one or more of the above embodiments, the material of the insulating glue includes: at least one of vinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyacrylic acid, styrene-butadiene rubber, acrylic (ester) styrene-butadiene rubber, epoxy resin or nylon.

[0028] In one or more of the above embodiments, the packaging bag includes a first flexible portion and a second flexible portion, the first flexible portion and the second flexible portion are arranged to form a main body portion, and the first flexible portion and the second flexible portion are connected to form a sealing portion that seals the receiving cavity.

[0029] In a second aspect of the present application, an electronic device is provided, which includes the secondary battery in any one of the above embodiments.

[0030] In the above embodiment, the space occupied by the secondary battery is reduced and the energy density is increased, which is beneficial to increasing the service life of the electronic device and improving the performance of the electronic device.

[0031] The secondary battery in this application includes an electrode assembly, a packaging bag, and insulating adhesive. The packaging bag includes a main body and a sealing portion. The main body includes a first side wall and a second side wall arranged opposite each other along a first direction. The sealing portion includes a first side seal, which includes a first connecting portion and a second connecting portion arranged in sequence. The first connecting portion is connected to the main body, and the second connecting portion is bent toward the main body relative to the first connecting portion. The first connecting portion and the first side wall form an angle greater than 0° and less than 90°. The thickness of the main body is less than the width of the first connecting portion. The insulating adhesive covers the end of the second connecting portion facing the main body, and the insulating adhesive bonds the first connecting portion and the second connecting portion. The insulating adhesive also bonds the second connecting portion to the main body. The angle between the first connecting portion and the first side wall reduces the space occupied by the first side seal, thereby facilitating an increase in the energy density of the secondary battery. The insulating adhesive covers the end of the second connecting portion facing the main body, so that the aluminum layer at the end of the second connecting portion facing the main body is not exposed, and the risk of the adhesive falling off is reduced. The insulating glue connects the first connecting part and the second connecting part, and the insulating glue also connects the second connecting part and the main body, which is beneficial to maintaining the shape of the angle between the first side seal and the first side wall, and is also beneficial to reducing the risk of deformation of the first connecting part and the second connecting part. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG1 is a schematic structural diagram of a secondary battery provided in one embodiment of the present application.

[0033] FIG2 is an exploded schematic diagram of a secondary battery provided in one embodiment of the present application.

[0034] FIG3 is a side view of a secondary battery provided in accordance with an embodiment of the present application.

[0035] FIG4 is a partial side view of a secondary battery provided in one embodiment of the present application.

[0036] FIG5 is a top view of a secondary battery provided in one embodiment of the present application.

[0037] FIG6 is a schematic diagram of an electronic device provided in an embodiment of the present application.

[0038] Description of Main Component Symbols Secondary Battery 100 Electrode Assembly 10 Packaging Bag 20 Main Body 21 First Side Wall 211 Second Side Wall 212 Third Side Wall 213 Fourth Side Wall 214 Fifth Side Wall 215 Sixth Side Wall 216 Sealing Portion 22 First Side Sealing Edge 221 First Connecting Portion 2212 Second Connecting Portion 2214 Second Side Sealing Edge 222 Top Sealing Edge 223 Receiving Cavity 23 First Flexible Portion 20a Second Flexible Portion 20b Insulating Adhesive 30 First Portion 31 Second Portion 32 First Tab 40 Second Tab 50 Device Main Body 200 Electronic Device 1000 First Direction X Second Direction Y Third Direction Z

[0039] The following specific implementation methods will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0041] It should be noted that, unless otherwise expressly specified or limited, terms such as "mounted," "connected," "connected," and "fixed" should be understood broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections. When a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be an intervening component. When a component is considered to be "located on" another component, it can be directly located on the other component or there may be an intervening component.

[0042] The terms "top", "side" and similar expressions used herein are for illustrative purposes only. Unless otherwise specified, the term "plurality" used herein refers to two or more than two.

[0043] The terms "first", "second", etc. are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implying the quantity, specific order or primary and secondary relationship of the technical features indicated.

[0044] The term "perpendicular" is used to describe an ideal position between two components. In actual production or use, the position between two components may be approximately perpendicular.

[0045] The term "parallel" is used to describe an ideal state between two components. In actual production or use, two components may be approximately parallel.

[0046] It should be noted that when a parameter is greater than, equal to, or less than a certain endpoint value, it should be understood that the endpoint value allows a tolerance of ±5%.

[0047] It should be understood that the dimensions of the layers, regions, films, plates, blocks, columns, projections, recesses, etc. shown in the drawings are provided for better understanding and more convenient description, and the present application is not limited to the dimensions shown in the drawings. Elements not relevant to the description are omitted from the details of this specification in order to make the present invention clear.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0049] Ultra-thin secondary batteries in the related art typically do not have folded edges. Instead, glue is applied to the ends of the edge seal to cover the aluminum layer of the aluminum-plastic film packaging to prevent exposure. This flat edge seal design occupies space in the width direction of the secondary battery, reducing energy density. Furthermore, the exposed glue layer on the edge seal may cause the glue to fall off and leak aluminum.

[0050] The present application discloses a secondary battery, which includes an electrode assembly, a packaging bag, and an insulating adhesive. The packaging bag includes a main body and a sealing part. A receiving cavity is provided in the main body, which receives the electrode assembly. The main body includes a first side wall and a second side wall arranged opposite to each other along a first direction. The first direction is the thickness direction of the secondary battery. The sealing part is connected to the main body and seals the receiving cavity. The sealing part includes a first side seal. The first side seal is provided on one side of the main body in a second direction perpendicular to the first direction. The first side seal includes a first connecting part and a second connecting part arranged in sequence. The first connecting part is connected to the main body, and the second connecting part is bent toward the main body relative to the first connecting part. An angle θ is formed between the first connecting part and the first side wall, satisfying 0°<θ<90°. Along the first direction, the thickness of the main body is H. Along the extension direction from the end where the first connecting part is connected to the main body to the end where the first connecting part is away from the main body, the width of the first connecting part is T1, satisfying H<T1. The insulating glue covers one end of the second connection part facing the main body, the insulating glue adheres the first connection part and the second connection part, and the insulating glue also adheres the second connection part and the main body.

[0051] The first connecting portion is angled with the first side wall, so that the first side seal is arranged at an angle greater than 0° and less than 90° with the first side wall as a whole, which reduces the space occupied by the first side seal. Compared with the solution of laying the seal flat, it is beneficial to reduce the width of the secondary battery in the second direction, and compared with the folded edge solution, it is beneficial to reduce the thickness of the secondary battery in the first direction, thereby facilitating the improvement of the energy density of the secondary battery. The insulating glue covers the end of the second connecting portion facing the main body, so that the aluminum layer of the end of the second connecting portion facing the main body is not exposed, and the insulating glue is located on the inside, reducing the risk of the glue falling off. The insulating glue connects the first connecting portion and the second connecting portion, and the insulating glue also connects the second connecting portion and the main body, which is beneficial to maintaining the shape of the angle between the first side seal and the first side wall, and is also beneficial to reducing the risk of deformation of the first connecting portion and the second connecting portion.

[0052] The following will describe some embodiments of the present application in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.

[0053] 1 and 2 , an embodiment of the present application provides a secondary battery 100 . The secondary battery 100 includes an electrode assembly 10 and a packaging bag 20 . The packaging bag 20 accommodates the electrode assembly 10 .

[0054] In some embodiments, the electrode assembly 10 includes a positive electrode sheet, a negative electrode sheet, and a separator disposed between the positive electrode sheet and the negative electrode sheet, and the separator is used to separate the positive electrode sheet from the negative electrode sheet.

[0055] In some embodiments, the positive electrode sheet, the separator, and the negative electrode sheet are stacked to form a stacked structure. In other embodiments, the positive electrode sheet, the separator, and the negative electrode sheet are stacked and then wound to form a wound structure.

[0056] In some embodiments, the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer that are stacked together, and the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer that are stacked together.

[0057] In some embodiments, the positive electrode current collector may be a metal layer including at least one of aluminum, nickel, tantalum, and titanium, such as aluminum foil. The negative electrode current collector may be a metal layer including at least one of copper, nickel, tantalum, and titanium, such as copper foil.

[0058] In some embodiments, the positive electrode active material layer includes a positive electrode active material, which may include at least one of lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium iron phosphate, lithium manganese iron phosphate, or lithium manganese oxide. The negative electrode active material layer includes a negative electrode active material, which may include at least one of graphite, hard carbon, soft carbon, silicon, a silicon-oxygen material, and a silicon-carbon material.

[0059] In some embodiments, the isolation film is made of insulating film materials such as polyethylene film, polypropylene film, polyester film, or polyimide film.

[0060] In some embodiments, the secondary battery 100 is a soft-pack battery, and the packaging bag 20 is an aluminum-plastic film. In some embodiments, the aluminum-plastic film may consist of an outermost nylon layer, an inner aluminum layer, and a heat-seal layer. The aluminum-plastic film packaging bag 20 for the secondary battery 100 is manufactured using a cutting process, so the aluminum layer is typically exposed at the edge of the aluminum-plastic film.

[0061] In some embodiments, referring to Figures 1 and 2 , the packaging bag 20 includes a main body 21 and a sealing portion 22 . The main body 21 defines a receiving cavity 23 that receives the electrode assembly 10 . The sealing portion 22 is connected to the main body 21 and is used to seal the receiving cavity 23 .

[0062] In some embodiments, referring to FIG. 1 and FIG. 3 , the main body 21 includes a first side wall 211 and a second side wall 212 oppositely disposed along a first direction X. The first direction X is the thickness direction of the secondary battery 100 .

[0063] In some embodiments, referring to FIG. 1 and FIG. 3 , the main body 21 further includes a third sidewall 213 and a fourth sidewall 214 oppositely disposed along a second direction Y, where the second direction Y is perpendicular to the first direction X.

[0064] In some embodiments, referring to FIG. 1 and FIG. 3 , the main body 21 further includes a fifth sidewall 215 and a sixth sidewall 216 oppositely disposed along a third direction Z. The first direction X, the second direction Y, and the third direction Z are perpendicular to each other.

[0065] In some embodiments, referring to Figures 1 and 2, the packaging bag 20 includes a first flexible portion 20a and a second flexible portion 20b, the first flexible portion 20a and the second flexible portion 20b are arranged to form a main body portion 21, and the first flexible portion 20a and the second flexible portion 20b are connected to form a sealing portion 22 that seals the receiving cavity 23.

[0066] In some embodiments, please refer to Figures 1 and 2, one side of the first flexible portion 20a is connected to one side of the second flexible portion 20b, and the connection position of the first flexible portion 20a and the second flexible portion 20b is folded to connect the first flexible portion 20a and the second flexible portion 20b, and the first flexible portion 20a and the second flexible portion 20b are enclosed to form a main body portion 21, and the portion where the first flexible portion 20a and the second flexible portion 20b are connected forms a sealing portion 22.

[0067] In some embodiments, referring to FIG. 1 and FIG. 3 , the sealing portion 22 includes a first side sealing edge 221 . The first side sealing edge 221 is disposed on one side of the main body portion 21 in the second direction Y.

[0068] In some embodiments, the first side seal 221 is connected to the third side wall 213 .

[0069] In some embodiments, referring to Figures 1 and 3 , the sealing portion 22 further includes a second side seal 222 and a top seal 223. The second side seal 222 is provided on a side of the main body 21 in the second direction Y that is away from the first side seal 221, and the top seal 223 is provided on a side of the main body 21 in the third direction Z. The top seal 223 connects the first side seal 221 and the second side seal 222. The third direction Z is perpendicular to the first direction X and the second direction Y.

[0070] In some embodiments, the second side sealing edge 222 is connected to the fourth side wall 214 , and the top sealing edge 223 is connected to the fifth side wall 215 or the sixth side wall 216 .

[0071] In some embodiments, referring to Figures 1 and 2, the secondary battery 100 further includes a first electrode tab 40 and a second electrode tab 50, and the electrode assembly 10 is connected to the first electrode tab 40 and the second electrode tab 50. The first electrode tab 40 and the second electrode tab 50 extend out of the packaging bag 20 from the top seal 223 to lead the polarity of the electrode assembly 10 out of the packaging bag 20.

[0072] In some embodiments, the first tab 40 is connected to the positive electrode plate. The material of the first tab 40 can be the same as that of the positive electrode current collector, and the first tab 40 serves as the positive electrode. The second tab 50 is connected to the negative electrode plate. The material of the second tab 50 can be the same as that of the negative electrode current collector, and the second tab 50 serves as the negative electrode.

[0073] In some embodiments, the first tab 40 is connected to the negative electrode plate. The material of the first tab 40 can be the same as that of the negative electrode current collector, and the first tab 40 serves as the negative electrode. The second tab 50 is connected to the positive electrode plate. The material of the second tab 50 can be the same as that of the positive electrode current collector, and the second tab 50 serves as the positive electrode.

[0074] It should be noted that the first side edge seal 221 and the second side edge seal 222 may have substantially the same structure in some embodiments. The following mainly describes some embodiments of the specific configuration of the first side edge seal 221. The configuration and beneficial effects of the second side edge seal 222 may refer to any of the following embodiments related to the first side edge seal 221 and will not be repeated herein.

[0075] In some embodiments, referring to FIG. 3 , the first side seal 221 includes a first connecting portion 2212 and a second connecting portion 2214, which are sequentially arranged. The first connecting portion 2212 is connected to the main body 21, and the second connecting portion 2214 is bent toward the main body 21 relative to the first connecting portion 2212. An angle θ is formed between the first connecting portion 2212 and the first sidewall 211, satisfying 0°<θ<90°. The second connecting portion 2214 and the first connecting portion 2212 are stacked. Along a first direction X, the main body 21 has a thickness H. Along a direction extending from the end of the first connecting portion 2212 connected to the main body 21 to the end of the first connecting portion 2212 away from the main body 21, the first connecting portion 2212 has a width T1, satisfying H<T1. The secondary battery 100 further includes an insulating adhesive 30 , which covers one end of the second connection portion 2214 facing the main body 21 , adheres the first connection portion 2212 and the second connection portion 2214 , and also adheres the second connection portion 2214 and the main body 21 .

[0076] With this arrangement, firstly, the first connecting portion 2212 forms an angle with the first side wall 211, so that the entire first side seal 221 is arranged at an angle with the first side wall 211. This reduces the space occupied by the first side seal 221. Compared to a solution with flat edge seals, this helps reduce the width of the secondary battery 100 in the second direction Y, and compared to a folded edge solution, it helps reduce the thickness of the secondary battery 100 in the first direction X, thereby improving the energy density of the secondary battery 100. Secondly, the insulating adhesive 30 covers the end of the second connecting portion 2214 facing the main body 21, preventing the aluminum layer on the end of the second connecting portion 2214 facing away from the main body 21 from being exposed. Furthermore, the insulating adhesive 30 is located on the inside, reducing the risk of adhesive shedding. Thirdly, the insulating adhesive 30 bonds the first connecting portion 2212 and the second connecting portion 2214, and also bonds the second connecting portion 2214 to the main body 21. This helps improve the overall structural strength of the first side edge seal 221 and maintains the angle between the first side edge seal 221 and the first sidewall 211. The insulating adhesive 30 bonding the first connecting portion 2212 and the second connecting portion 2214 also helps improve the tightness of the fit between the first connecting portion 2212 and the second connecting portion 2214. When the first connecting portion 2212 or the second connecting portion 2214 is squeezed or impacted, the first portion 31 can inhibit deformation of the first connecting portion 2212 and the second connecting portion 2214, thereby reducing the possibility of the first connecting portion 2212 opening relative to the second connecting portion 2214.

[0077] It should be noted that, referring to FIG. 4 , along the first direction X, the height of the first side edge seal 221 is H1 , along the second direction Y, the width of the first side edge seal 221 is W1 , and tanθ=H1 / W1 .

[0078] Compared with the solution in which the first side sealing edge 221 and the second side sealing edge 222 are flattened, the percentage of increase in the volume energy density of the secondary battery 100 in the above embodiment can be calculated as follows:

[0079] The structures of the first side edge seal 221 and the second side edge seal 222 are basically the same. It is defined that the overall width of the secondary battery 100 along the second direction Y when the first side edge seal 221 and the second side edge seal 222 are laid flat is W, and the width of the first side edge seal 221 along the second direction Y when the first side edge seal 221 is laid flat is M. In the above embodiment, the percentage of energy density improvement of the secondary battery 100 is [(W-2×W1) / (W-2×M)]%.

[0080] In some embodiments, referring to FIG. 3 , the insulating adhesive 30 bonds the second connection portion 2214 and the third sidewall 213 of the main body 21 .

[0081] In some embodiments, referring to Figures 3 and 4 , the insulating adhesive 30 includes a first portion 31 disposed between the first connecting portion 2212 and the second connecting portion 2214. The first portion 31 bonds the first connecting portion 2212 and the second connecting portion 2214. The height of the first portion 31, extending from the end of the first connecting portion 2212 connected to the main body 21 to the end of the first connecting portion 2212 away from the main body 21, is D1, satisfying 0 < D1 < T1. This condition of 0 < D1 < T1 improves the overall structural strength of the first side edge seal 221 and enhances the tightness of the fit between the first connecting portion 2212 and the second connecting portion 2214.

[0082] In some embodiments, satisfying D1≤0.7T1 is beneficial to maintaining the angle between the first side seal 221 and the first side wall 211, saving the insulating adhesive 30, saving costs, and reducing the risk that the weight of the end of the first side seal 221 away from the first side wall 211 is too heavy, so that the first side seal 221 tends to open.

[0083] In some embodiments, satisfying D1 ≥ 0.5 mm is beneficial to further improving the overall structural strength of the first side edge seal 221 and further improving the tightness of the fit between the first connecting portion 2212 and the second connecting portion 2214 .

[0084] As an illustrative example, D1 can be any one of 0.5mm, 0.52mm, 0.54mm, 0.55mm, 0.56mm, 0.58mm, 0.6mm, 0.62mm, 0.64mm, 0.65mm, 0.66mm, 0.68mm, 0.7mm, 0.72mm, 0.74mm, 0.75mm, 0.76mm, 0.78mm, 0.8mm, 0.82mm, 0.84mm, 0.85mm, 0.86mm, 0.88mm, 0.9mm, 0.92mm, 0.94mm, 0.95mm, 0.96mm, 0.98mm or 1mm.

[0085] In some embodiments, as shown in FIG4 , the insulating adhesive 30 further includes a second portion 32 disposed between the second connecting portion 2214 and the main body 21. At least a portion of the second portion 32 is disposed between the second connecting portion 2214 and the third sidewall 213, bonding the second connecting portion 2214 and the third sidewall 213. Along the first direction X, the height of the second portion 32 is D2, satisfying 0 < D2 < H. This helps maintain the angle between the first side seal 221 and the first sidewall 211, thereby reducing the risk of the insulating adhesive 30 overflowing the main body 21.

[0086] In some embodiments, satisfying D2≤0.4H is beneficial for maintaining the angle between the first side seal 221 and the first side wall 211, saving the insulating glue 30, reducing costs, and reducing the risk of the insulating glue 30 overflowing and causing poor appearance. In addition, it can also reduce the risk of the third side wall 213 being broken when the insulating glue 30 falls after curing.

[0087] In some embodiments, satisfying 0.3 mm ≤ D2 ≤ 0.5 mm is beneficial for maintaining the angle between the first side sealing edge 221 and the first side wall 211 , and also reduces the risk of the insulating adhesive 30 overflowing from the main body 21 .

[0088] As an illustrative example, D1 can be any one of 0.3mm, 0.31mm, 0.32mm, 0.33mm, 0.34mm, 0.35mm, 0.36mm, 0.37mm, 0.38mm, 0.39mm, 0.4mm, 0.41mm, 0.42mm, 0.43mm, 0.44mm, 0.45mm, 0.46mm, 0.47mm, 0.48mm, 0.49mm or 0.5mm.

[0089] There are many ways to set the insulating glue 30. The following is an example of a specific way to set the insulating glue 30:

[0090] For example, when the first side seal 221 is flattened, the extension direction of the first connection portion 2212 from one end close to the main body 21 to one end away from the main body 21 is parallel to the first side wall 211, and the second connection portion 2214 is parallel to the first side wall 211 from one end close to the first connection portion 2212 to one end away from the main body 21. At this time, the insulating glue 30 can be placed on the first connection part 2212, the second connection part 2214, the end of the second connection part 2214 away from the first connection part 2212, and the main body 21, and then the first side sealing edge 221 is bent to form the first connection part 2212 and the second connection part 2214, and the first connection part 2212 is made to form an angle relative to the first side wall 211. At this time, the insulating glue 30 adheres to the first connection part 2212 and the second connection part 2214 under the action of folding and squeezing. The insulating glue 30 also adheres the second connection part 2214 and the main body 21, and the insulating glue 30 covers the end of the second connection part 2214 facing the main body 21.

[0091] For another example, when the second connection portion 2214 is bent toward the main body 21 compared to the first connection portion 2212, and the first connection portion 2212 forms an angle with the first side wall 211, the insulating glue 30 is directly dripped between the second connection portion 2214 and the third side wall 213 of the main body 21. The insulating glue 30 between the second connection portion 2214 and the third side wall 213 of the main body 21 adheres the second connection portion 2214 to the main body 21. The insulating glue 30 also flows from between the second connection portion 2214 and the third side wall 213 of the main body 21 to between the first connection portion 2212 and the second connection portion 2214, so that the insulating glue 30 covers the end of the second connection portion 2214 facing the main body 21, and also adheres the first connection portion 2212 and the second connection portion 2214.

[0092] In some embodiments, the insulating adhesive 30 can be applied to the first side sealing edge 221 or the main body 21 by smearing or spot coating, etc., which is not specifically limited here.

[0093] In some embodiments, the material of the insulating adhesive 30 includes at least one of vinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymers, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyacrylic acid, styrene-butadiene rubber, acrylic (ester) styrene-butadiene rubber, epoxy resin, or nylon.

[0094] In some embodiments, referring to Figures 3 and 5, along the third direction Z, the connection length between the main body 21 and the first connection portion 2212 is L1, the length of the insulating adhesive 30 is L2, and the first direction X, the second direction Y, and the third direction Z are perpendicular to each other, satisfying 4L1 / 5≤L2≤L1. Such a configuration is beneficial for improving the bonding effect of the insulating adhesive 30 and maintaining the angle between the first side seal 221 and the first side wall 211.

[0095] In some embodiments, referring to FIG. 3 and FIG. 4 , along the extension direction of the second connection portion 2214 from one end close to the main body 21 to the other end away from the main body 21 , the width of the second connection portion 2214 is T2, satisfying 0mm<|T2-T1|≤0.5mm.

[0096] When |T2-T1| satisfies the above range, the width of the second connection portion 2214 is smaller than the width of the first connection portion 2212, which is conducive to reserving a space between the end of the second connection portion 2214 facing the main body 21 and the end where the first connection portion 2212 and the main body 21 are connected. On the one hand, the reserved space can accommodate the insulating glue 30, which is conducive to allowing the insulating glue 30 to cover the end of the second connection portion 2214 facing the main body 21. On the other hand, the reserved space can also allow the insulating glue 30 in a fluid state to pass through, which is conducive to allowing the insulating glue 30 to flow between the first connection portion 2212 and the second connection portion 2214.

[0097] When |T2-T1| satisfies the above range, the distance from the end of the second connecting portion 2214 facing the main body 21 to the end where the first connecting portion 2212 and the main body 21 are connected will not be too large, so that the height of the insulating glue 30 between the second connecting portion 2214 and the third side wall 213 in the first direction X will not be too high, which is beneficial to reducing the use of the insulating glue 30, playing a role in weight reduction, and is beneficial to improving the energy density of the secondary battery 100 and reducing costs.

[0098] As an illustrative example, |T2-T1| can be any one of 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.31mm, 0.32mm, 0.33mm, 0.34mm, 0.35mm, 0.36mm, 0.37mm, 0.38mm, 0.39mm, 0.4mm, 0.41mm, 0.42mm, 0.43mm, 0.44mm, 0.45mm, 0.46mm, 0.47mm, 0.48mm, 0.49mm or 0.5mm.

[0099] It should be noted that in some embodiments, the second side edge seal 222 is bonded to the insulating adhesive 30. The relationship and beneficial effects among the second side edge seal 222, the insulating adhesive 30, and the main body 21 can be referred to in any of the above embodiments regarding the relationship and beneficial effects among the first side edge seal 221, the insulating adhesive 30, and the main body 21, and will not be further described here.

[0100] In some embodiments, 25°≤θ≤75° is satisfied. When the angle θ between the first connection portion 2212 and the first sidewall 211 satisfies the above relationship, it is beneficial to further reduce the overall occupied space of the secondary battery 100, thereby further improving the energy density of the secondary battery 100.

[0101] As an illustrative example, θ can be any one of 25°, 26°, 28°, 30°, 32°, 34°, 35°, 36°, 38°, 40°, 42°, 44°, 45°, 46°, 48°, 50°, 52°, 54°, 55°, 56°, 58°, 60°, 62°, 64°, 65°, 66°, 68°, 70°, 72°, 74° or 75°.

[0102] In some embodiments, referring to FIG. 4 , along the second direction Y, the orthographic projection of the first side seal 221 is located between the plane of the first side wall 211 and the plane of the second side wall 212. This configuration prevents the first side seal 221 from extending beyond the first and second side walls 211, 212 in the first direction X. Consequently, the thickness of the secondary battery 100 in the first direction X is not affected by the first side seal 221, thereby reducing the overall thickness of the secondary battery 100.

[0103] It should be noted that a side view as shown in Figure 4 or a cross-sectional view with a perspective similar to that of Figure 4 can be made, and extension lines can be drawn for the first side wall 211 and the second side wall 212. When the first side edge seal 221 is located between the extension lines of the first side wall 211 and the second side wall 212, the orthographic projection of the first side edge seal 221 in the second direction Y is located between the plane where the first side wall 211 is located and the plane where the second side wall 212 is located.

[0104] In some embodiments, 0.5 mm ≤ H < 1.5 mm, and 1.5 mm ≤ T1 ≤ 3 mm are satisfied. When the thickness H of the main body 21 in the first direction X is within the range of 0.5 mm ≤ H < 1.5 mm, the secondary battery 100 is an ultra-thin secondary battery 100 .

[0105] As an illustrative example, H may be any one of 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, or 1.4 mm.

[0106] As an illustrative example, T1 can be any one of 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm or 3mm.

[0107] In order to verify the influence of the angle change of the first side seal 221 and the second side seal 222 on the volume energy density of the secondary battery 100 and the opening of the first side seal 221 and the second side seal 222 , the following experiment was conducted.

[0108] The capacity test of the secondary battery 100 is performed as follows: the secondary battery 100 is first charged to the full charge voltage at a constant current of 0.5C, and then discharged to 3.0V at 0.2C, and the capacity (Ah) and energy (Wh) discharged during the process are obtained.

[0109] The volume energy density is calculated as follows: Volume energy density (Wh / L) = energy released during testing (Wh) / (length of secondary battery 100 (dm) × width of secondary battery 100 (dm) × thickness of secondary battery 100 (dm))

[0110] First side edge seal 221 opening test method:

[0111] The testing process is as follows: First, the distance from the end of the first connection portion 2212 away from the main body 21 to the third side wall 213 along the second direction Y of each of the 100 secondary batteries 100 is measured, and recorded as X1, X2, ..., X100. The 100 cells are then placed in an environment with a temperature of 65°C and a humidity of 90% for 120 hours. After returning to room temperature, the distance from the end of the first connection portion 2212 away from the main body 21 to the third side wall 213 along the second direction Y of each of the 100 secondary batteries 100 is measured again, and recorded as X1'X2'...X100'. Finally, the open distance Δ before and after the test is calculated for each cell, i.e., Δ1 = X1'-X1, Δ2 = X2'-X2, ..., Δ100 = X100'-X100. Cells that meet the Δ specification of 0±0.2mm are considered passed, while those that do not meet the specification are considered failed. The overall pass rate (%) is then calculated.

[0112] The method for testing the opening of the second side edge seal 222 may refer to the method for testing the opening of the first side edge seal 221 , and will not be described in detail here.

[0113] The specific implementation of the secondary battery 100 in the examples and comparative examples will be described below.

[0114] Example:

[0115] A secondary battery 100 is assembled as follows:

[0116] (1) Preparation of negative electrode sheet: Mix the negative electrode active materials artificial graphite, conductive carbon black (Super P), and styrene-butadiene rubber (SBR) in a weight ratio of 96:1.5:2.5, add deionized water as a solvent, prepare a slurry with a weight percentage of 70wt%, and stir evenly. The slurry is evenly coated on one surface of a negative electrode current collector copper foil with a thickness of 10μm, leaving an empty foil area at the edge of the copper foil, and dried at 110℃ to obtain a negative electrode sheet with a coating thickness of 150μm and a single-sided negative electrode active material layer. Repeat the above steps on the other surface of the negative electrode sheet to obtain a negative electrode sheet with a double-sided negative electrode active material layer. Then, the excess empty foil area is removed by laser die-cutting to obtain a negative electrode tab.

[0117] (2) Preparation of positive electrode sheet: The positive electrode active material lithium cobalt oxide (LiCoO2), conductive carbon black (Super P), and polyvinylidene fluoride (PVDF) are mixed in a weight ratio of 97.5:1.0:1.5, and N-methylpyrrolidone (NMP) is added as a solvent to prepare a slurry with a solid content of 75wt%, and stirred evenly. The slurry is evenly coated on one surface of a positive electrode current collector aluminum foil with a thickness of 12μm, leaving an empty foil area at the edge of the aluminum foil, and then dried at 90°C to obtain a positive electrode sheet with a positive electrode active material layer thickness of 100μm. When preparing other first electrodes coated on both sides, repeat the above coating steps on the other surface of the aluminum foil. Then, the excess empty foil area is removed by laser die-cutting to obtain a positive electrode tab.

[0118] (3) Preparation of electrolyte: In a dry argon atmosphere, ethylene carbonate (EC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC) were first mixed in a mass ratio of EC:EMC:DEC = 30:50:20 to form a basic organic solvent. Then, lithium salt lithium hexafluorophosphate (LiPF6) was added to the basic organic solvent to dissolve and mix evenly to obtain an electrolyte with a lithium salt concentration of 1.15 mol / L.

[0119] (4) Preparation of the isolation film: A three-layer isolation film is used, which includes a first adhesive layer, a first substrate layer, and a first adhesive layer stacked in layers. The first substrate layer is made of polyethylene (PE), the first adhesive layer contains a first adhesive, and the first adhesive layer also contains inorganic ceramic particles Al2O3.

[0120] (5) Preparation of electrode assembly 10: The positive electrode sheet, the separator and the negative electrode sheet are stacked and arranged, and the stacked structure is hot-pressed on a flat plate for 10 seconds at a temperature of 80° C. and a pressure of 1.5 MPa to form an electrode assembly 10 for use.

[0121] (6) Assembly of the electrode assembly 10: Place the aluminum-plastic film with the holes punched and formed in the assembly fixture with the holes facing upwards, place the electrode assembly 10 in the holes, and apply external force to press it. Then, cover the electrode assembly 10 with the holes punched and formed by another aluminum-plastic film with the holes facing downwards, and heat-seal the four sides of the two aluminum-plastic films by hot pressing to obtain the assembled electrode assembly 10. The aluminum-plastic film on the outside of the assembled electrode assembly 10 is a packaging bag 20. The packaging bag 20 includes a main body 21 for accommodating the electrode assembly 10 and a first edge seal, a second edge seal, and a top edge seal 223 connected to the main body 21. The main body 21 includes a first side wall 211, a second side wall 212, a third side wall 213, and a fourth side wall 214. The assembled electrode assembly 10 is square, and the finished product has a thickness of 1.2 mm, a width of 34.5 mm, and a length of 90 mm. The width T1 of the first connecting part 2212 is 1.3 mm, and the width T2 of the second connecting part 2214 is 1.0 mm

[0122] (7) Folding and gluing: Fold the first side edge 221 180 degrees to form a first connecting portion 2212 and a second connecting portion 2214. Fold the folded first side edge 221 again so that the first connecting portion 2212 is set at an angle to the first side wall 211. The angle between the first connecting portion 2212 and the first side wall 211 is θ. Then, drip insulating glue 30 between the second connecting portion 2214 and the third side wall 213 until the insulating glue 30 covers the end of the second connecting portion 2214 facing the main body 21. The insulating glue 30 adheres the first connecting portion 2212 and the second connecting portion 2214. The insulating glue 30 also adheres the second connecting portion 2214 to the main body 21. The second side edge 222 is processed in the same way as the first side edge 221 so that the second side edge 222 has an angle β with the first side wall 211.

[0123] (8) Liquid injection and packaging: The electrolyte is injected into the assembled electrode assembly 10, and the secondary battery 100 is manufactured through processes such as vacuum packaging, static standing, hot pressing, and shaping.

[0124] Comparative Example:

[0125] The difference from the embodiment is that the first side seal 221 and the second side seal 222 in Comparative Example 1 are not folded, and the first side seal 221 and the second side seal 222 are flattened. In Comparative Example 2, the first side seal 221 and the second side seal 222 are directly folded to form a 90-degree angle with the first side wall 211. The insulating adhesive 30 in Comparative Example 3 does not bond the first connecting portion 2212 and the second connecting portion 2214. The insulating adhesive 30 in Comparative Example 4 does not bond the second connecting portion 2214 to the main body 21. The insulating adhesive 30 in Comparative Example 5 does not bond either the first connecting portion 2212 and the second connecting portion 2214 or the second connecting portion 2214 to the main body 21.

[0126] The main parameter control and test results of Example 1 and Comparative Examples 1-5 are shown in Table 1 below:

[0127] Table 1

[0128] According to Table 1, compared with Comparative Examples 1-2, Example 1 satisfies 0°<θ<90° and 0°<β<90°, which is beneficial to reducing the occupied space of the secondary battery 100 and improving the volume energy density of the secondary battery 100.

[0129] According to Table 1 above, compared with comparative examples 3-5, embodiment 1 has both the first part 31 and the second part 32, the insulating glue 30 is bonded to the first connecting portion 2212 and the second connecting portion 2214, and the insulating glue 30 is also bonded to the second connecting portion 2214 and the main body 21, which is beneficial to improving the overall structural strength of the first side edge seal 221, and is beneficial to maintaining the shape of the angle between the first side edge seal 221 and the first side wall 211, and is beneficial to reducing the probability of the first side edge seal 221 and the second side edge seal 222 opening.

[0130] The main parameter control of Example 2-12 and the test results of the opening of the first side sealing edge 221 and the second side sealing edge 222 of the secondary battery 100 are shown in Table 2 below:

[0131] Table 2

[0132] According to Table 2, compared with Example 2, Example 1 and Examples 3-9 satisfy D1 ≥ 0.5 mm, which is beneficial to further improve the overall structural strength of the first side edge seal 221 and reduce the probability of the first side edge seal 221 and the second side edge seal 222 opening.

[0133] According to Table 2, compared with Example 10, Examples 1, 11, and 12 satisfy 0.3 mm ≤ D2 ≤ 0.5 mm, which is beneficial for maintaining the angle between the first side edge seal 221 and the first side wall 211 and reducing the probability of the first side edge seal 221 and the second side edge seal 222 opening.

[0134] The main parameter control and volume energy density test results of Examples 13-26 are shown in Table 3 below:

[0135] Table 3

[0136] According to Table 3, compared with Examples 13-15 and 26, Examples 1 and 16-25 satisfy 25°≤θ≤75° and 25°≤β≤75°, which is beneficial to further reduce the occupied space of the secondary battery 100 and further improve the volume energy density of the secondary battery 100.

[0137] In some embodiments, referring to Figures 3 and 4 , along the first direction X, the end of the first connection portion 2212 connected to the main body portion 21 is closer to the first side wall 211 than the second side wall 212. This arrangement can fully utilize the space occupied by the secondary battery 100 in the first direction X, thereby improving the utilization rate of the space occupied by the secondary battery 100.

[0138] In some embodiments, referring to Figures 3 and 4, the main body 21 further includes a third side wall 213 and a fourth side wall 214 arranged opposite to each other along the second direction Y, and one end of the first connecting portion 2212 connected to the main body 21 is connected to the third side wall 213 and the first side wall 211 respectively. Such a configuration can more fully utilize the occupied space of the secondary battery 100 in the first direction X, thereby facilitating further improving the utilization rate of the occupied space of the secondary battery 100.

[0139] Referring to FIG6 , an embodiment of the present application further provides an electronic device 1000, which includes the secondary battery 100 of any of the aforementioned embodiments. Because the electronic device 1000 employs the technical solution of the secondary battery 100 of any of the aforementioned embodiments, it at least has the beneficial effects brought about by the technical solution of the secondary battery 100 of any of the aforementioned embodiments, which will not be further elaborated here.

[0140] In some embodiments, referring to FIG. 6 , the electronic device 1000 further includes a device body 200 , and the secondary battery 100 is installed in the device body 200 .

[0141] In some embodiments, the electronic device 1000 may be a mobile phone, a tablet computer, an e-reader, AR glasses, VR glasses, etc., which are not listed here one by one.

[0142] In addition, those skilled in the art should recognize that the above embodiments are merely intended to illustrate the present application and are not intended to limit the present application. As long as they are within the substantive scope of the present application, appropriate changes and modifications to the above embodiments are within the scope disclosed in the present application.

Claims

1. A secondary battery, characterized in that: It includes an electrode assembly, a packaging bag and insulating glue, and the packaging bag includes: a main body, wherein a receiving cavity is provided in the main body, the receiving cavity receives the electrode assembly, the main body comprising a first side wall and a second side wall arranged opposite to each other along a first direction, the first direction being a thickness direction of the secondary battery; and a sealing portion connected to the main body and sealing the receiving cavity, the sealing portion including a first side seal, the first side seal being provided on one side of the main body in a second direction perpendicular to the first direction; the first side seal including a first connecting portion and a second connecting portion provided in sequence, the first connecting portion being connected to the main body, the second connecting portion being bent toward the main body relative to the first connecting portion, an angle θ being formed between the first connecting portion and the first sidewall, satisfying 0°<θ<90°; a thickness of the main body along the first direction being H, a width of the first connecting portion being T1 along an extension direction from an end where the first connecting portion is connected to the main body to an end where the first connecting portion is away from the main body, satisfying H<T1; The insulating adhesive covers one end of the second connecting portion facing the main body, the insulating adhesive bonds the first connecting portion and the second connecting portion, and the insulating adhesive also bonds the second connecting portion and the main body.

2. The secondary battery according to claim 1, wherein The main body further includes a third side wall and a fourth side wall arranged opposite to each other along the second direction, and the first side seal is connected to the third side wall; The insulating adhesive includes a first portion and a second portion, wherein the first portion is disposed between the first connecting portion and the second connecting portion, and the first portion adheres the first connecting portion and the second connecting portion; at least a portion of the second portion is disposed between the second connecting portion and the third side wall, and the second portion adheres the second connecting portion and the third side wall; Along the extending direction from one end of the first connecting portion connected to the main body to the end of the first connecting portion away from the main body, the height of the first part is D1, and along the first direction, the height of the second part is D2, satisfying 0<D1<T1, and 0<D2<H.

3. The secondary battery according to claim 2, wherein Satisfy D1≤0.7T1 and D2≤0.4H.

4. The secondary battery according to claim 2, wherein: 0.5 mm ≤ H < 1.5 mm, and 1.5 mm ≤ T1 ≤ 3 mm; and the secondary battery further satisfies at least one of the following conditions: (1) D1 ≥ 0.5 mm; (2)0.3mm≤D2≤0.5mm.

5. The secondary battery according to claim 3, wherein Along the third direction, the connection length between the main body and the first connection portion is L1, the length of the insulating adhesive is L2, and 4L1 / 5≤L2≤L1 is satisfied; The first direction, the second direction, and the third direction are perpendicular to each other.

6. The secondary battery according to claim 1, wherein Along an extending direction from an end of the second connecting portion close to the main body to an end of the second connecting portion away from the main body, a width of the second connecting portion is T2, satisfying 0mm<|T2-T1|≤0.5mm.

7. The secondary battery according to claim 1, wherein Satisfies 25°≤θ≤75°.

8. The secondary battery according to claim 1, wherein Along the second direction, an orthographic projection of the first side edge seal is located between a plane where the first side wall is located and a plane where the second side wall is located.

9. The secondary battery according to any one of claims 1 to 8, characterized in that Along the first direction, one end of the first connecting portion connected to the main body is closer to the first side wall than to the second side wall.

10. The secondary battery according to claim 9, wherein The main body further includes a third side wall and a fourth side wall arranged opposite to each other along the second direction, and the first connecting portion is connected to the third side wall and the first side wall respectively.

11. The secondary battery according to any one of claims 1 to 8, characterized in that: The material of the insulating glue includes: at least one of vinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyacrylic acid, styrene-butadiene rubber, acrylic (ester) styrene-butadiene rubber, epoxy resin or nylon.

12. The secondary battery according to any one of claims 1 to 8, characterized in that: The packaging bag includes a first flexible portion and a second flexible portion. The first flexible portion and the second flexible portion are arranged to form the main body portion. The first flexible portion and the second flexible portion are connected to form the sealing portion that seals the receiving cavity.

13. An electronic device, characterized in that: The secondary battery according to any one of claims 1 to 12 is included.

Images