Electrochemical device, preparation method thereof and electronic device

Abstract

The invention discloses an electrochemical device, a preparation method thereof and an electronic device. An electrochemical device includes a packaging bag, an electrode assembly, and a conductive plate. The electrode assembly is arranged in the packaging bag, and the conductive plate is electrically connected to the electrode assembly. The packaging bag comprises a containing part used for containing the electrode assembly and a sealing part connected with the containing part, and the conductive plate extends out of the packaging bag from the sealing part. The first direction is the thickness direction of the electrode assembly, the second direction is perpendicular to the first direction and points to the conductive plate from the electrode assembly, and the containing part comprises a first wall and a second wall which are oppositely arranged in the second direction. The accommodating part further comprises a reinforcing part. The reinforcing part comprises at least one first convex part which is integrally arranged on the first wall; the first wall comprises a first surface and a second surface which are oppositely arranged in the second direction; the first convex part forms a first bulge on the first surface and forms a first recess on the second surface; the problem of deformation of the packaging bag can be solved.

Description

Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to an electrochemical device, a method for preparing the electrochemical device, and an electronic device having the electrochemical device. Background Art

[0002] With the popularity of consumer electronic products such as laptops, mobile phones, handheld game consoles, tablets, mobile power supplies and drones, people have increasingly stringent requirements on the safety performance of electrochemical devices (such as soft-pack batteries).

[0003] The electrochemical device usually includes a packaging bag and an electrode assembly disposed in the packaging bag. In the related art, a pit is formed on an aluminum-plastic film, the electrode assembly is placed in the pit, and the aluminum-plastic film is packaged to obtain a packaging bag. However, in subsequent processes (such as hot pressing and vacuum process links) or even during the use of the battery, part of the packaging bag facing the head or tail of the electrode assembly is prone to collapse or other deformation, which not only leads to poor appearance, but also the internal space occupied by the collapse needs to be considered when designing the length of the electrode assembly, which reduces the energy density of the electrochemical device. Summary of the invention

[0004] In view of this, it is necessary to provide an electrochemical device and a preparation method thereof that can improve the deformation problem of packaging bags. In addition, it is also necessary to provide an electronic device having the electrochemical device.

[0005] In a first aspect, the present application provides an electrochemical device, comprising a packaging bag, an electrode assembly and a conductive plate. The electrode assembly is disposed in the packaging bag, and the conductive plate is electrically connected to the electrode assembly. The packaging bag comprises a housing portion for accommodating the electrode assembly and a sealing portion connected to the housing portion, and the conductive plate extends out of the packaging bag from the sealing portion. The first direction is the thickness direction of the electrode assembly, the second direction is perpendicular to the first direction and is the direction in which the conductive plate protrudes from the electrode assembly, and the housing portion comprises a first wall and a second wall arranged oppositely along the second direction. The housing portion also comprises a reinforcing portion. The reinforcing portion comprises at least one first protrusion integrally arranged on the first wall. The first wall comprises a first surface and a second surface arranged oppositely along the second direction, the first protrusion forming a first protrusion on the first surface and a first depression on the second surface. When viewed from the second direction, the first protrusion and the first depression formed by a first protrusion overlap.

[0006] The present application provides a first protrusion on the first wall, and the first protrusion can improve the structural strength and deformation resistance of the first wall, and reduce the risk of collapse or other deformation of the first wall. This can not only improve the appearance of the electrochemical device, but also make the size of the accommodating portion along the second direction more stable. Therefore, when designing the size of the electrode assembly along the second direction, there is no need to consider the internal space occupied when the first wall collapses, thereby improving the energy density of the electrochemical device.

[0007] Based on the first aspect, in some possible implementations, the first protrusion is protruding from the first wall in a direction away from the electrode assembly. Therefore, the first protrusion does not occupy the internal space of the packaging bag, and the first protrusion can also be used to accommodate part of the free electrolyte, thereby improving the liquid storage capacity of the electrochemical device, thereby further improving the energy density and cycle performance of the electrochemical device.

[0008] Based on the first aspect, in some possible implementations, the sealing portion is connected to the second wall. Therefore, by providing the first protrusion on the first wall without the sealing portion, the structural strength and deformation resistance of the first wall which is more prone to deformation are improved.

[0009] Based on the first aspect, in some possible implementations, the reinforcing portion further includes at least one second protrusion integrally disposed on the second wall. The second wall includes a third surface and a fourth surface disposed opposite to each other along a second direction, and the second protrusion forms a second protrusion on the third surface and forms a second depression on the fourth surface. When viewed from the second direction, the second protrusion and the second depression formed by a second protrusion overlap. Therefore, the second protrusion can improve the structural strength and deformation resistance of the second wall and reduce the risk of deformation of the second wall, which can not only further improve the appearance of the electrochemical device, but also make the size of the accommodating portion along the second direction more stable.

[0010] Based on the first aspect, in some possible implementations, the sealing portion includes a first connecting edge integrally connected to the accommodating portion. The second wall includes a first region and a second region respectively connected to the first connecting edge, and the first region and the second region are respectively located on both sides of the first connecting edge along the first direction. Along the first direction, the width of the first region is greater than the width of the second region. The second convex portion is provided in the first region. Therefore, by providing the second convex portion in the first region with a larger width, the structural strength and anti-deformation ability of the first region that is more prone to deformation are improved.

[0011] Based on the first aspect, in some possible implementations, when viewed from the second direction, the reinforcement portion (such as the first convex portion or the second convex portion) is strip-shaped. The angle between the extension direction of the reinforcement portion and the third direction is α, 45°≤α≤90°, and the third direction is perpendicular to the first direction and the second direction, respectively. Therefore, the deformation resistance of the first wall or the second wall can be further improved, and the risk of electrochemical corrosion caused by easy damage to the metal layer of the packaging film when preparing the reinforcement portion can also be reduced. Moreover, when the extension direction of the reinforcement portion is inclined relative to the third direction, the reinforcement portion can be used to accommodate more free electrolyte and improve the liquid storage capacity of the electrochemical device.

[0012] Based on the first aspect, in some possible implementations, the width of the reinforcing portion (such as the first convex portion or the second convex portion) along the third direction is W, and the dimension of the first wall or the second wall along the third direction is W.0 , 0.1W 0 ≤W≤0.9W 0 Therefore, the reinforcement portion can effectively improve the structural strength and deformation resistance of the first wall, and reduce the risk of deformation of the first wall or the second wall.

[0013] Based on the first aspect, in some possible implementations, 0.5 mm ≤ W ≤ 95 mm, thereby further improving the structural strength and deformation resistance of the first wall or the second wall and reducing the risk of deformation of the first wall or the second wall.

[0014] Based on the first aspect, in some possible implementations, the distance between two adjacent reinforcement portions on the first wall or the second wall along the third direction is D, and the size of the first wall or the second wall along the third direction is W. 0 , 0.1W 0 ≤D≤0.9W 0 Therefore, there is a sufficient spacing between two adjacent reinforcement parts, which reduces the risk of electrochemical corrosion caused by the metal layer of the packaging film being easily damaged when the reinforcement parts are prepared due to the reinforcement parts being too dense. At the same time, the above spacing will not be too large, and the reinforcement parts can effectively improve the structural strength and deformation resistance of the first wall or the second wall, reducing the risk of deformation of the first wall or the second wall.

[0015] Based on the first aspect, in some possible implementations, the length of the reinforcing portion (such as the first convex portion or the second convex portion) is L, and the dimension of the first wall or the second wall along the first direction is L 0 , 0.1L 0 ≤L≤0.9L 0 Therefore, while making the reinforcing portion have a certain length, considering that the edge of the first wall or the second wall along the first direction may have a rounded corner area, by setting the upper limit of L, the reinforcing portion can be formed in the straight area of ​​the first wall or the second wall except the rounded corner, so that the reinforcing portion can fully play the structural reinforcement role, so the reinforcing portion can effectively improve the structural strength and deformation resistance of the first wall or the second wall, and reduce the risk of deformation of the first wall or the second wall.

[0016] Based on the first aspect, in some possible implementations, 1 mm ≤ L ≤ 15 mm, thereby further improving the structural strength and deformation resistance of the first wall or the second wall and reducing the risk of deformation of the first wall or the second wall.

[0017] Based on the first aspect, in some possible implementations, the height of the reinforcement portion (such as the first convex portion or the second convex portion) is h1, 0.1 mm.

[0018] The second aspect of the present application provides an electronic device, which includes a storage compartment and the electrochemical device as described above. The electrochemical device is arranged in the storage compartment. The electronic device is powered by the electrochemical device, and the deformation problem of the packaging bag of the electrochemical device is improved.

[0019] The third aspect of the present application provides a method for preparing the electrochemical device as above, comprising the following steps: providing a multilayer packaging material, the multilayer packaging material comprising a first packaging film and a second packaging film, the first packaging film comprising a first main body area and a first edge area connected to each other, and the second packaging film comprising a second main body area and a second edge area connected to each other; stamping and forming at least the first main body area by a molding die, the molding die comprising a male mold and a female mold arranged oppositely, the male mold comprising a first molding body, the female mold comprising a second molding body, a molding part protruding from the first molding body or the second molding body, the first molding body and the second molding body cooperate to form a groove on the first main body area, and the molding part forms a reinforcement part on the inner wall of the groove; electrically connecting the electrode assembly to the conductive plate, and placing the electrode assembly with the conductive plate in the groove; placing the first packaging film and the second packaging film opposite to each other, and packaging the first edge area and the second edge area to form a sealing part, the conductive plate extends out of the packaging bag from the sealing part, and the second main body area and the first main body area with the groove form a receiving part. The deformation problem of the packaging bag of the electrochemical device obtained by the above preparation method is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0021] Figure 1 It is a schematic structural diagram of an electrochemical device according to one embodiment of the present application when viewed from a first direction.

[0022] Figure 2A In some embodiments Figure 1 The electrochemical device is shown in a cross-sectional view along the cutting line II-II.

[0023] Figure 2B In some other embodiments Figure 1 The electrochemical device is shown in a cross-sectional view along the cutting line II-II.​

[0024] Figure 3 for Figure 2A The electrochemical device shown is a schematic structural diagram when viewed from a second direction.

[0025] Figure 4 Schematic diagrams of the structures of electrochemical devices in other embodiments when viewed from a first direction.

[0026] Figure 5 are cross-sectional views of electrochemical devices in other embodiments.

[0027] Figure 6 for Figure 5 The electrochemical device shown is a schematic structural diagram when viewed from a second direction.

[0028] Figure 7 for Figure 1 Schematic diagram of the structure of the electrochemical device before packaging.

[0029] Figure 8 for Figure 7 A cross-sectional view of a first packaging film of an electrochemical device is shown.

[0030] Fig. 9 for Figure 7 A cross-sectional view of a second packaging film of an electrochemical device is shown.

[0031] Fig.10 This is a cross-sectional view of an electrochemical device according to another embodiment of the present application.

[0032] Fig.11 are cross-sectional views of electrochemical devices in other embodiments.

[0033] Fig.12 are cross-sectional views of electrochemical devices in other embodiments.

[0034] Fig.13 This is a flow chart of a method for preparing an electrochemical device according to one embodiment of the present application.

[0035] Fig.14 In some embodiments Fig.13 A schematic structural diagram of the molding die used in the preparation method shown.

[0036] Fig.15 In some other embodiments Fig.13 A schematic structural diagram of the molding die used in the preparation method shown.

[0037] Fig.16 It is a schematic structural diagram of an electronic device according to one embodiment of the present application.

[0038] Main component symbols

[0039] Electronic device, 1; packaging bag, 2; containing part, 11; sealing part, 12; electrode assembly, 20; first conductive plate, 30; first electrode ear, 31; second conductive plate, 40; electrochemical device, 100, 200; first packaging film, 101; first protective layer, 101A; first metal layer, 101B; first polymer layer, 101C; second packaging film, 102; second protective layer, 102A; second metal layer, 102B; second polymer layer, 102C; reinforcing part, 110; first wall, 111; first surface, 111A; second surface, 111B; second wall, 112; third surface, 112A; fourth surface, 112B; first protrusion, 113; second convex part, 114; first connecting edge, 120; sealing area, 121; transition area, 122; molding mold, 300; male mold, 301; female mold, 302; battery compartment, 1001; first main area, 1011; first edge area, 1012; second main area, 1021; second edge area, 1022; first protrusion, 1131; first depression, 1132; second protrusion, 1141; second depression, 1142; first area, 1121; second area, 1122; first molding body, 3010; second molding body, 3020; molding part, 3030; groove, R; angle, α; width, W; spacing, D; length, L; height, h1; size, W 0 , L 0 ; first direction, X; first side, X1; second side, X2; second direction, Y; third direction, Z.

[0040] The following specific implementation methods will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0041] The technical scheme in the embodiment of the present application is described clearly and in detail below. Obviously, the described embodiment is a part of the embodiment of the present application, rather than all the embodiments. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present application. The terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0042] Hereinafter, the embodiments of the present application will be described in detail. However, the present application can be embodied in many different forms and should not be construed as being limited to the exemplary embodiments illustrated herein. Rather, these exemplary embodiments are provided so that the present application is thoroughly and in detail communicated to those skilled in the art.

[0043] In addition, for simplicity and clarity, in the accompanying drawings, the size or thickness of various components, layers may be amplified. Throughout the entire text, the same numerical value refers to the same element. As used herein, the term "and / or", "and / or" includes any and all combinations of one or more related enumerated items. In addition, it should be understood that when element A is referred to as "connecting" element B, element A may be directly connected to element B, or there may be an intermediate element C and element A and element B may be indirectly connected to each other.

[0044] Further, the use of “may” when describing embodiments of the present application means “one or more embodiments of the present application”.

[0045] The technical terms used herein are for the purpose of describing specific embodiments and are not intended to limit the present application. As used herein, the singular form is intended to also include the plural form, unless the context clearly indicates otherwise. It should be further understood that the term "comprising", when used in this specification, refers to the presence of narrated features, values, steps, operations, elements and / or components, but does not exclude the presence or increase of one or more other features, values, steps, operations, elements, components and / or combinations thereof.

[0046] Spatial related terms, such as "on" and the like can be used herein for convenient description, to describe the relationship between an element or feature and another element (multiple elements) or feature (multiple features) as illustrated in the figure. It should be understood that, in addition to the directions described in the figure, spatial related terms are intended to include different directions of equipment or devices in use or operation. For example, if the equipment in the figure is turned over, the elements described as "above" or "on" other elements or features will be oriented "below" or "below" other elements or features. Therefore, the exemplary term "on" may include the direction above and below. It should be understood that although the terms first, second, third, etc. can be used herein to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are used to distinguish an element, component, region, layer or part from another element, component, region, layer or part. Therefore, the first element, component, region, layer or part discussed below may be referred to as the second element, component, region, layer or part without departing from the teaching of the exemplary embodiment.

[0047] In this application, the parameter values ​​being greater than, less than, or not equal to the designed relationship need to exclude the reasonable errors of the measuring equipment.

[0048] See also Figure 1 and Figure 2AIn one embodiment of the present application, an electrochemical device 100 is provided, which includes a packaging bag 10, an electrode assembly 20, an electrolyte (not shown) and a conductive plate. The electrode assembly 20 and the electrolyte are arranged in the packaging bag 10. The conductive plate may include a first conductive plate 30 and a second conductive plate 40. The first conductive plate 30 is electrically connected to the electrode assembly 20 or is electrically connected to the electrode assembly 20 through a first electrode tab 31. The second conductive plate 40 is electrically connected to the electrode assembly 20 or is electrically connected to the electrode assembly 20 through a second electrode tab (not shown). Moreover, the first conductive plate 30 and the second conductive plate 40 extend out of the packaging bag 10 to connect to an external element (not shown). A three-dimensional coordinate system is established according to a first direction X, a second direction Y and a third direction Z which are perpendicular to each other, wherein the first direction X is the thickness direction of the electrode assembly 20, the second direction Y is the direction in which the first conductive plate 30 or the second conductive plate 40 protrudes from the electrode assembly 20, and in some embodiments, the third direction Z is the direction from the first conductive plate 30 to the second conductive plate 40. Among them, although Figure 2A The first direction X indicated in the figure has a specific vector direction to illustrate the thickness direction of the electrode assembly 20. However, it can be understood that the opposite direction of the indicated direction can also be the thickness direction of the electrode assembly 20. Therefore, the first direction X has a first side X1 and a second side X2 opposite to the first side X1.

[0049] The packaging bag 10 includes a receiving portion 11 and a sealing portion 12 connected to the receiving portion 11. The electrode assembly 20 and the electrolyte are disposed in the receiving portion 11. The receiving portion 11 includes a first wall 111 and a second wall 112 disposed opposite to each other in the second direction Y. Figure 3 , at least part of the surface where the first wall 111 is located extends in the first direction X and the third direction Z. At least part of the surface where the second wall 112 is located extends in the first direction X and the third direction Z. In some embodiments, the sealing portion 12 is connected to the second wall 112, and the sealing portion 12 includes a first connecting edge 120 integrally connected to the accommodating portion 11, and the second wall 112 extends from the first connecting edge 120 along the second side X2. The first conductive plate 30 and the second conductive plate 40 can both extend out of the packaging bag 10 from the sealing portion 12. Please refer to Figure 4 In other embodiments, in order to meet the demand of high current charging and reduce the internal resistance of the electrode sheet of the electrode assembly 20, the width of the first pole tab 31 or the second pole tab in the third direction Z can be increased accordingly. At this time, the number of the sealing parts 12 is two and they are respectively connected to the first wall 111 and the second wall 112, and the first conductive plate 30 and the second conductive plate 40 extend out of the packaging bag 10 from the two sealing parts 12. Therefore, the risk of the first pole tab 31 and the second pole tab having a larger width contacting and causing a short circuit can be reduced, and a larger welding operation space can be provided when the first conductive plate 30 and the second conductive plate 40 are respectively welded on the first pole tab 31 and the second pole tab.

[0050] like Figure 7 As shown, the packaging bag 10 includes a first packaging film 101 and a second packaging film 102 that are relatively arranged in a first direction X, and the materials of the first packaging film 101 and the second packaging film 102 are both multi-layer packaging materials. The first packaging film 101 includes a first main body area 1011 and a first edge area 1012 that are connected, and the second packaging film 102 includes a second main body area 1021 and a second edge area 1022 that are connected. The first main body area 1011 and the second main body area 1021 together constitute the containing portion 11 of the packaging bag 10, and the first edge area 1012 and the second edge area 1022 are connected to jointly constitute the sealing portion 12 of the packaging bag 10. In some embodiments, the first packaging film 101 and the second packaging film 102 are an integrated structure before packaging, and the first packaging film 101 and the second packaging film 102 are obtained by folding a piece of packaging film. As shown Figure 8 As shown, the first packaging film 101 may include a first protective layer 101A, a first metal layer 101B and a first polymer layer 101C stacked in sequence. The first polymer layer 101C is closer to the electrode assembly 20 than the first protective layer 101A. The material of the first protective layer 101A may be a polymer resin, which can be used to protect the first metal layer 101B, reduce the risk of damage to the first metal layer 101B due to external force, and at the same time delay the air penetration of the external environment, and maintain the electrochemical device 100 in a normal operating environment. In some embodiments, the material of the first protective layer 101A can be selected from at least one of polyethylene terephthalate, polybutylene terephthalate, polyvinylidene fluoride, polytetrafluoroethylene, polypropylene, polyamide and polyimide. The first metal layer 101B can be used to delay the moisture penetration of the external environment and reduce the damage to the electrode assembly 2020 caused by external forces. In some embodiments, the first metal layer 101B may be an aluminum foil layer or a steel foil layer. The first polymer layer 101C has the property of melting upon heating, can be used for packaging, and can reduce the risk of the multilayer sheet being dissolved or swollen by the organic solvent in the electrolyte. The first polymer layer 101C can also be used to reduce the risk of the electrolyte in the electrolyte contacting the first metal layer 101B and causing the metal layer to be corroded. In some embodiments, the first polymer layer 101C includes a first polymer material, which can be selected from at least one of polyethylene, polypropylene, polyurethane, and polyimide.

[0051] like Fig. 9 As shown, the second packaging film 102 may include a second protective layer 102A, a second metal layer 102B, and a second polymer layer 102C stacked in sequence. It can be understood that when the first packaging film 101 and the second packaging film 102 are obtained by folding a packaging film, the materials of the second protective layer 102A, the second metal layer 102B, and the second polymer layer 102C are the same as those of the first protective layer 101A, the first metal layer 101B, and the first polymer layer 101C. Figure 7 As shown, when preparing the packaging bag 10, a forming mold 300 (in Fig.14 and Fig.15 (as shown in the figure) at least one of the first main area 1011 and the second main area 1021 is punched to form a groove R, and then the electrode assembly 20 is placed in the groove R, and then the first packaging film 101 and the second packaging film 102 are placed opposite to each other, and a certain temperature and pressure are applied to the first edge area 1012 and the second edge area 1022 by using the sealing head of the packaging equipment, so that the first polymer layer 101C in the first edge area 1012 and the second polymer layer 102C in the second edge area 1022 melt and bond together to form a sealing portion 12. Figure 7 It is shown that the first main body area 1011 is punched and formed to obtain a groove R for accommodating the electrode assembly 20. In other embodiments, the first main body area 1011 and the second main body area 1021 can also be punched and formed to obtain the groove R respectively. Therefore, when the first packaging film 101 and the second packaging film 102 are placed opposite to each other, the two grooves R together form a accommodating space for accommodating the electrode assembly 20.

[0052] like Figure 2A and Figure 3 As shown, the receiving portion 11 further includes a reinforcing portion 110 . The reinforcing portion 110 includes at least one first protrusion 113 integrally provided on the first wall 111 . Figure 3 As shown above, in some embodiments, the first wall 111 is integrally provided with a plurality of first protrusions 113, and the plurality of first protrusions 113 are arranged in intervals and substantially parallel along the third direction Z. The first protrusions 113 are provided protruding from the first wall 111 in a direction away from the electrode assembly 20. Figure 5 and Figure 6 As shown, the first protrusion 113 may also be arranged to protrude from the first wall 111 in a direction toward the electrode assembly 20. Specifically, the first wall 111 includes a first surface 111A and a second surface 111B arranged opposite to each other along the second direction Y, and the second surface 111B faces the electrode assembly 20. Figure 2A and Figure 3 As shown, when the first protrusion 113 is protruded from the first wall 111 in a direction away from the electrode assembly 20, the first protrusion 113 forms a first protrusion 1131 on the first surface 111A and a first recess 1132 on the second surface 111B. Figure 5 and Figure 6 As shown, when the first protrusion 113 is protruded from the first wall 111 in the direction toward the electrode assembly 20, the first protrusion 113 forms a first depression 1132 on the first surface 111A and forms a first protrusion 1131 on the second surface 111B. When viewed from the second direction Y, the first protrusion 1131 and the first depression 1132 formed by the first protrusion 113 overlap.

[0053] When the first main area 1011 is punched and formed by the molding die 300 to obtain the groove R, the molding die 300 simultaneously forms the first convex portion 113 on the inner wall of the groove R. In some embodiments, the inner wall of the groove R is the first wall 111. Figure 2A As shown, the first wall 111 includes a second connecting edge 1110 connected to the second packaging film 102. When the first packaging film 101 and the second packaging film 102 are obtained by folding a packaging film, the second connecting edge 1110 is also the folding point between the first packaging film 101 and the second packaging film 102. The first convex portion 113 is connected to the second connecting edge 1110 in the first direction X. Figure 2B As shown, in other embodiments, if the folding points of the first packaging film 101 and the second packaging film 102 are changed or the molding method of the first protrusion 113 is changed, the first protrusion 113 can also be separated from the second connecting edge 1110 in the first direction X.

[0054] In the embodiment of the present application, the first convex portion 113 is provided on the first wall 111. The first convex portion 113 can improve the structural strength and anti-deformation capability of the first wall 111, and reduce the risk of collapse or other deformation of the first wall 111. This can not only improve the appearance of the electrochemical device 100, but also make the size of the accommodating portion 11 along the second direction Y more stable. Therefore, when designing the size of the electrode assembly 20 along the second direction Y, it is not necessary to consider the internal space occupied when the first wall 111 collapses, thereby improving the energy density of the electrochemical device 100. In particular, when the sealing portion 12 is connected to the second wall 112, the sealing portion 12 and the first conductive plate 30 and the second conductive plate 40 sandwiched in the sealing portion 12 can play a certain structural reinforcement role on the second wall 112, and by providing the first convex portion 113 on the first wall 111 without the sealing portion 12, the structural strength and anti-deformation capability of the first wall 111, which is more prone to deformation, are improved. Moreover, when the first protrusion 113 protrudes from the first wall 111 in a direction away from the electrode assembly 20, the first protrusion 113 will not occupy the internal space of the packaging bag 10, and the first protrusion 113 can also be used to accommodate part of the free electrolyte, thereby improving the liquid storage capacity of the electrochemical device 100, thereby further improving the energy density and cycle performance of the electrochemical device 100.

[0055] like Figure 3 and Figure 6As shown, in some embodiments, when viewed from the second direction Y, the first convex portion 113 may be in the shape of a strip, a circle, an ellipse, a triangle, a square, a trapezoid, a rhombus or other polygonal shapes. In this embodiment, in order to further improve the structural strength of the first wall 111 and facilitate manufacturing, the first convex portion 113 may be set to be in the shape of a strip. The angle between the extension direction of the first convex portion 113 and the third direction Z is defined as α, 45°≤α≤90°. Among them, when the extension direction of the first convex portion 113 is inclined relative to the third direction Z, the above-mentioned angle α refers to the acute angle formed between the extension direction of the first convex portion 113 and the third direction Z. By defining the lower limit of the angle α, not only the deformation resistance of the first wall 111 can be further improved (for example, when the extrusion force to which the electrochemical device 100 is subjected has a component force along the first direction X, the deformation resistance of the first wall 111 under the component force can be improved), but also the risk of electrochemical corrosion caused by the easy damage of the first metal layer 101B or the second metal layer 102B when preparing the first convex portion 113 can be reduced. Furthermore, when the extension direction of the first protrusion 113 is inclined relative to the third direction Z, that is, when 45°≤α<90°, the first protrusion 113 can be used to accommodate more free electrolyte, thereby improving the liquid storage capacity of the electrochemical device 100 .

[0056] like Figure 3 and Figure 6 As shown, in some embodiments, the width of the first protrusion 113 along the third direction Z is W, and the dimension of the first wall 111 along the third direction Z is W. 0 , 0.1W 0 ≤W≤0.9W 0 Therefore, the first convex portion 113 can effectively improve the structural strength and anti-deformation capability of the first wall 111, and reduce the risk of deformation of the first wall 111. Furthermore, 0.5mm≤W≤95mm can be set, thereby further improving the structural strength and anti-deformation capability of the first wall 111, and reducing the risk of deformation of the first wall 111.

[0057] like Figure 3 and Figure 6 As shown, in some embodiments, the distance between two adjacent first protrusions 113 along the third direction Z is D, and the size of the first wall 111 along the third direction Z is W. 0 , 0.1W 0 ≤D≤0.9W 0Therefore, by setting the lower limit of D, there is a sufficient spacing between two adjacent first protrusions 113, which reduces the risk of electrochemical corrosion caused by the first metal layer 101B or the second metal layer 102B being easily damaged when preparing the first protrusions 113 due to the over-dense first protrusions 113. At the same time, by setting the upper limit of D, the above spacing will not be too large, and the first protrusions 113 can effectively improve the structural strength and deformation resistance of the first wall 111, reducing the risk of deformation of the first wall 111.

[0058] like Figure 3 and Figure 6 As shown, in some embodiments, the length of the first protrusion 113 along its extension direction is L, and the dimension of the first wall 111 along the first direction X is L 0 , 0.1L 0 ≤L≤0.9L 0 Therefore, while the first convex portion 113 has a certain length, the first convex portion 113 can be formed in the straight area of ​​the first wall 111 except the rounded corners, so that the first convex portion 113 can fully play the role of structural reinforcement. Therefore, the first convex portion 113 can effectively improve the structural strength and anti-deformation ability of the first wall 111, and reduce the risk of deformation of the first wall 111. Furthermore, 1mm≤L≤15mm can be set, thereby further improving the structural strength and anti-deformation ability of the first wall 111, and reducing the risk of deformation of the first wall 111.

[0059] like Figure 2A and Figure 5 As shown, in some embodiments, the height of the first protrusion 113 protruding from the first wall 111 is h1, 0.1 mm

[0060] See also Fig.10 Another embodiment of the present application also provides an electrochemical device 200, which is different from the above-mentioned electrochemical device 100 in that the reinforcing portion 110 further includes at least one second protrusion 114 integrally provided on the second wall 112. In some embodiments, the second wall 112 is integrally provided with a plurality of second protrusions 114, and the plurality of second protrusions 114 are arranged in intervals and substantially parallel along the third direction Z. The second protrusion 114 protrudes from the first wall 111 in a direction away from the electrode assembly 20. Fig.11 ​As shown, the second protrusion 114 may also be arranged to protrude from the second wall 112 in a direction toward the electrode assembly 20. Specifically, the second wall 112 includes a third surface 112A and a fourth surface 112B arranged opposite to each other along the second direction Y, and the fourth surface 112B is arranged facing the electrode assembly 20. Fig.10 As shown, when the second protrusion 114 is protruded from the first wall 111 in a direction away from the electrode assembly 20, the second protrusion 114 forms a second protrusion 1141 on the third surface 112A and a second recess 1142 on the fourth surface 112B. Fig.11 As shown, when the second protrusion 114 is protruded from the second wall 112 in the direction toward the electrode assembly 20, the second protrusion 114 forms a second recess 1142 on the third surface 112A and a second protrusion 1141 on the fourth surface 112B. When viewed from the second direction Y, the second protrusion 1141 and the second recess 1142 formed by the second protrusion 1141 overlap.

[0061] In the embodiment of the present application, a second convex portion 114 is provided on the second wall 112. The second convex portion 114 can improve the structural strength and anti-deformation ability of the second wall 112, and reduce the risk of collapse or other deformation of the second wall 112, which can not only further improve the appearance of the electrochemical device 200, but also make the size of the receiving portion 11 along the second direction Y more stable. In particular, when the second convex portion 114 is provided protruding from the second wall 112 in the direction away from the electrode assembly 20, the second convex portion 114 will not occupy the internal space of the packaging bag 10, and the second convex portion 114 can also be used to accommodate part of the free electrolyte, which can not only improve the storage capacity of the electrochemical device 200, but also reduce the impact of the free electrolyte on the second wall 112 during mechanical abuse (such as falling, collision, etc.), reduce the risk of leakage caused by the sealing portion 12 connected to the second wall 112 being flushed open by the free electrolyte, and improve the safety performance of the electrochemical device 200.

[0062] Among them, the width of the second convex portion 114 along the third direction Z, the spacing between two adjacent second convex portions 114 along the third direction Z, the length of the second convex portion 114, and the height of the second convex portion 114 can refer to the corresponding dimensions of the first convex portion 113, respectively, and no further description is given here. For example, the width of the second convex portion 114 can be approximately equal to the width of the first convex portion 113, the spacing between the first convex portions 113 can be approximately equal to the spacing between the first convex portions 113, the length of the second convex portion 114 can be approximately equal to the length of the first convex portion 113, and the height of the second convex portion 114 can be approximately equal to the height of the first convex portion 113. In some embodiments, when the second convex portion 114 is protruding from the second wall 112 in the direction toward the electrode assembly 20, since the sealing portion 12 can play a certain structural reinforcement role on the second wall 112, the length of the second convex portion 114 can also be set to be less than the length of the first convex portion 113. Therefore, while the second protrusion 114 can improve the structural strength and deformation resistance of the second wall 112 , the influence of the second protrusion 114 on the energy density of the electrochemical device 200 is reduced.

[0063] In some cases, the sealing portion 12 needs to be bent onto the second wall 112 to reduce the size of the electrochemical device 100 in the second direction Y. Specifically, the sealing portion 12 may include a sealing area 121 and a transition area 122 connected in the second direction Y, and the transition area 122 is also connected to the accommodating portion 11. The connection between the transition area 122 and the accommodating portion 11 is the above-mentioned first connecting edge 120. Along the first direction X, the thickness of the transition area 122 is less than the thickness of the accommodating portion 11 and greater than the thickness of the sealing area 121. At the transition area 122, the first polymer layer 101C of the first packaging film 101 is close to the second polymer layer 201C of the second packaging film 102, but the second polymer layer 201C is not bonded. When the sealing portion 12 is bent onto the second wall 112, the bend may actually be located in the transition area 122, thereby reducing the impact on the packaging strength of the sealing portion 12. When the second protrusion 114 is protruded from the first wall 111 in a direction away from the electrode assembly 20, the height h1 of the second protrusion 114 is set to satisfy: 0.1

[0064] like Fig.12 ​As shown, in some embodiments, the structure of the second wall 112 can also be changed. For example, the second wall 112 may include a first area 1121 and a second area 1122 respectively connected to the first connecting edge 120, and the first area 1121 and the second area 1122 are respectively located on both sides of the first connecting edge 120 along the first direction X. Specifically, the first area 1121 extends from the first connecting edge 120 along the first side X1, and the second area 1122 extends from the first connecting edge 120 along the second side X2. Along the first direction X, the width of the first area 1121 is greater than the width of the second area 1122. That is, the first area 1121 is a deep pit surface, and the second area 1122 is a shallow pit surface. At this time, the second convex portion 114 is provided in the first area 1121, so that the structural strength and anti-deformation ability of the first area 1121, which is more prone to deformation, are improved. It is understandable that in other embodiments, without considering the complexity of the process, the second protrusion 114 can also be simultaneously provided in the second region 1122 , so as to further improve the structural strength and deformation resistance of the second wall 112 and reduce the risk of deformation of the second wall 112 .

[0065] The electrochemical devices 100 and 200 of the present application may be lithium secondary batteries, including lithium metal secondary batteries, lithium ion secondary batteries, lithium polymer secondary batteries or lithium ion polymer secondary batteries.

[0066] See also Fig.13 In one embodiment of the present application, a method for preparing the electrochemical device 100 (or electrochemical device 200) is also provided. According to different requirements, the order of the steps of the preparation method can be changed, and some steps can be omitted or combined. The preparation method comprises the following steps:

[0067] Step S1, providing a multilayer packaging material, which includes a first packaging film 101 and a second packaging film 102. The first packaging film 101 includes a first main body region 1011 and a first edge region 1012 connected to each other, and the second packaging film 102 includes a second main body region 1021 and a second edge region 1022 connected to each other.

[0068] Step S2: stamping at least the first main body area 1011 by using the molding die 300.

[0069] Among them, see Fig.14, the molding die 300 includes a male mold 301 and a female mold 302 that are relatively arranged. The male mold 301 includes a first molding body 3010, and the female mold 302 includes a second molding body 3020. A molding portion 3030 is protrudingly provided on the first molding body 3010 or the second molding body 3020. Among them, the first packaging film 101 can be placed on the second molding body 3020, and then the first molding body 3010 is controlled to be stamped in a direction toward the second molding body 3020, so that the first main body area 1011 of the first packaging film 101 is stamped into the cavity of the second molding body 3020 and a groove R is formed. In the above-mentioned stamping and molding process, the molding portion 3030 can simultaneously form a reinforcing portion 110 on the inner wall of the groove R. As Figure 2A As shown, in some embodiments, the inner wall of the groove R is the first wall 111 .

[0070] For example, when it is necessary to form a reinforcing portion 110 on the first wall 111 that is protruding in a direction toward the electrode assembly 20, as shown in FIG. Fig.14 As shown, a first molding body 3010 having a molding part 3030 on the surface can be used. In this way, when the first molding body 3010 is punched to form a groove R in a direction toward the second molding body 3020, the molding part 3030 on the first molding body 3010 can simultaneously form a protruding reinforcement part 110 on the inner wall of the groove R. In particular, since the molding part 3030 punches out the reinforcement part 110 on the inner wall of the groove R, combined with reference to Figure 2A and Figure 7 , along the first direction X, the reinforcing portion 110 is connected to one edge of the inner wall of the groove R.

[0071] When it is necessary to form a reinforcing portion 110 on the first wall 111 that is protruding in a direction away from the electrode assembly 20, such as Fig.15 As shown, a second molding body 3020 having a molding portion 3030 on the surface can be used. In this way, when the first molding body 3010 is punched to form a groove R in a direction toward the second molding body 3020, the molding portion 3030 on the second molding body 3020 can simultaneously form a reinforcing portion 110 recessed on the inner wall of the groove R.

[0072] Step S3 , electrically connecting the electrode assembly 20 to the conductive plate, and placing the electrode assembly 20 with the conductive plate in the groove R.

[0073] Step S4, the first packaging film 101 and the second packaging film 102 are opposite to each other, and the first edge area 1012 and the second edge area 1022 are packaged to form a sealing portion 12, the conductive plate extends out of the packaging bag 10 from the sealing portion 12, and the second main body area 1021 and the first main body area 1011 with the groove R form a receiving portion 11.

[0074] See also Fig.16, one embodiment of the present application also provides an electronic device 1, the electronic device 1 includes a battery compartment 1001 and the above-mentioned electrochemical device 100 (or electrochemical device 200) disposed in the battery compartment 1001. Among them, the electrochemical device 100 of the present application is applicable to electronic devices 1 in various fields. The electronic device 1 is powered by the above-mentioned electrochemical device 100, and the deformation problem of the packaging bag 10 of the electrochemical device 100 is improved. In one embodiment, the electronic device 1 of the present application can be, but is not limited to, a laptop computer, a pen-input computer, a mobile computer, an e-book player, a portable phone, a portable fax machine, a portable copier, a portable printer, a head-mounted stereo headset, a video recorder, an LCD TV, a portable cleaner, a portable C machine, a mini CD, a transceiver, an electronic notepad, a calculator, a memory card, a portable recorder, a radio, a backup power supply, a motor, a car, a motorcycle, a power bicycle, a bicycle, a lighting fixture, a toy, a game console, a clock, an electric tool, a flashlight, a camera, a large household battery and a lithium ion capacitor, etc.

[0075] The present application is described in detail below through specific embodiments and comparative examples. Among them, the present application is described by taking the electrochemical device 100 as a laminated lithium-ion secondary battery as an example and combining the specific preparation process and testing method. Those skilled in the art should understand that the preparation method described in the present application is only an example, and any other suitable preparation method is within the scope of the present application.

[0076] Example 1

[0077] (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 solid content of 50wt%, and stir evenly. The slurry is evenly coated on one surface of a copper foil with a thickness of 8μm, and an empty foil area is reserved at the edge of the copper foil. Dry at 110°C to obtain a negative electrode sheet with a coating thickness of 100μm and coated on one side with a 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 negative electrode active material layer coated on both sides. Then, the excess empty foil area is cut off by laser die cutting to obtain a negative electrode ear.

[0078] (2) Preparation of positive electrode sheet: The positive electrode active material lithium cobalt oxide (LiCoO 2), conductive carbon black (Super P), and polyvinylidene fluoride (PVDF) are mixed in a weight ratio of 97.5:1.0:1.5, N-methylpyrrolidone (NMP) is added as a solvent, and a slurry with a solid content of 75wt% is prepared, and stirred evenly. The slurry is evenly coated on one surface of an aluminum foil with a thickness of 10μm, and an empty foil area is reserved at the edge of the aluminum foil. Dry at 90°C to obtain a positive electrode sheet with a positive active material layer thickness of 90μm. On the other surface of the positive electrode current collector aluminum foil, the above steps are repeated to obtain a positive electrode sheet coated with a positive active material layer on both sides. Then, the excess empty foil area is cut off by laser die-cutting to obtain a positive electrode ear.

[0079] (3) Preparation of electrolyte: In a dry argon atmosphere, organic solvents ethylene carbonate (EC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC) were first mixed at a mass ratio of EC:EMC:DEC = 30:50:20, and then lithium salt lithium hexafluorophosphate (LiPF4) was added to the organic solvent. 6 ) are dissolved and mixed evenly to obtain an electrolyte with a lithium salt concentration of 1.15 mol / L.

[0080] (4) Assembly of electrode assembly: The negative electrode sheet, the separator, and the positive electrode sheet are stacked in sequence to obtain an electrode assembly. The separator is a polyethylene (PE) film with a thickness of 5 μm. The positive electrode tab and the negative electrode tab are welded to the first conductive plate and the second conductive plate respectively by transfer welding. The first conductive plate is made of aluminum and the second conductive plate is made of nickel. The first packaging film (aluminum-plastic film, with a thickness of 115 μm) is punched and formed by a forming mold. The forming mold simultaneously forms a certain number of mutually spaced first convex portions on the inner wall of the groove, and then the electrode assembly is placed in the pit.

[0081] (5) Liquid injection packaging: injecting electrolyte into the groove of the first packaging film, placing the first packaging film and the second packaging film opposite to each other, and packaging the first edge area and the second edge area to obtain a packaging bag, wherein the first convex portion is integrally arranged on the first wall of the packaging bag and protrudes from the first wall in a direction away from the electrode assembly, and the first conductive plate and the second conductive plate extend out of the second wall of the packaging bag to obtain a packaging bag as shown in FIG. Figures 1 to 3 The secondary battery shown.

[0082] Example 2

[0083] The difference from Example 1 is that the first protrusion is replaced by a second protrusion integrally provided on the second wall of the packaging bag, and the second protrusion protrudes from the second wall in a direction away from the electrode assembly.

[0084] Comparative Example 1

[0085] The difference from the first embodiment is that a conventional molding die is used to punch the first packaging film, so that the first concave portion is not provided on the molded packaging bag.

[0086] Then, the secondary batteries prepared in each embodiment and comparative example were subjected to energy density test, drop test and cycle performance test, and the test results are recorded in Table 1.

[0087] The energy density test steps include: at a test temperature of 25°C, charging the secondary battery to 4.50V at a constant current of 0.7C, then charging to 0.05C at a constant voltage of 4.50V, standing for 5 minutes, discharging to 3.0V at a constant current of 0.2C, standing for 5 minutes, and obtaining the discharge capacity D of the secondary battery. After the secondary battery is charged to 3.95V at a constant current of 0.7C, it is then charged to 0.05C at a constant voltage of 3.95V, and then the length, width and height of the secondary battery are tested with a laser thickness gauge to calculate the volume V of the secondary battery. The energy density (ED) = D / V, in units of Wh / L.

[0088] The drop test steps are as follows: 1) Under the environmental condition of 23±2℃, record the open circuit voltage and internal resistance of the secondary battery (the test instrument is a voltage resistance tester, manufacturer: Dongguan Lijia Precision Instrument Co., Ltd., model: LNG-SY1-0020-DQ); 2) Put the secondary battery into the fixture bin, and use the automatic drop device to drop the fixture bin with the secondary battery from a position of 1m to the cement floor in a round-trip manner, with the bottom surface of the fixture bin head, the left side, the right side, the back side, the front side, and the top side as a landing. The cycle consists of 3 drops, i.e. 18 times; 3) the battery is dropped from a position of 1.5 m to a cement floor in a circle of landing on the bottom, left, right, back, front and top of the fixture head. The cycle consists of 3 drops, i.e. 18 times; 4) the voltage of the secondary battery is measured after each drop. If the secondary battery catches fire or explodes, the drop is stopped; otherwise, the drop is continued; 5) after the drop, observe whether the first wall or the second wall of the packaging bag collapses. If not, the secondary battery is judged to have passed the drop test.

[0089] Among them, the cycle performance test is a capacity retention test, and the test steps are as follows: 1) At a test temperature of 25°C, the secondary battery is left to stand for 5 minutes, and the secondary battery is charged to 4.25V at a constant current of 3.4C, then charged to 4.4V at 2C, then charged to 4.50V at 1C, and then charged to 0.05C at a constant voltage of 4.50V, and then discharged to 3.0V at a constant current of 0.5C, and the discharge capacity C of the secondary battery is recorded. 11 ; 2) After the above 3.4C charge / 0.5C discharge cycle process is cycled 400 times, the discharge capacity C of the secondary battery is recorded. 12 , calculate 400 cycles capacity retention rate (%) = C12 / C 11 ×100%.

[0090] Table 1

[0091]

[0092] In the above table, the drop test pass rate is 9 / 10, which means that 9 out of 10 tested secondary batteries passed the test. The meanings of other ratio values ​​are similar.

[0093] From the data in Table 1, it can be seen that, compared with Comparative Example 1, Examples 1-3 respectively set reinforcement parts on the first wall and the second wall, which improves the structural strength and anti-deformation ability of the first wall and the second wall, so the drop test pass rate of the secondary battery is higher. Compared with Example 3, the reinforcement part (i.e., the first convex part) of Example 1-2 is protruded away from the electrode assembly, and the first convex part does not occupy the internal space of the packaging bag, and can also be used to accommodate part of the free electrolyte, so the energy density and cycle capacity protection rate of the secondary battery are higher.

[0094] Example 4-26

[0095] The difference from the first embodiment lies in the values ​​of the angle α, the width W, the length L or the height h1 of the first protrusion.

[0096] Then, the secondary batteries prepared in each embodiment and comparative example were subjected to energy density test and drop test, and the test results are recorded in Table 2.

[0097] Table 2

[0098]

[0099] From the data in Table 2, it can be seen that compared with Example 7, the angle α of the first convex portion of Examples 1 and 4-6 satisfies: 45°≤α≤90°, which improves the structural strength and anti-deformation ability of the first wall, so the pass rate of the drop test of the secondary battery is higher. Among them, since the extension direction of the first convex portion of Examples 1 and 4-5 is inclined, the first convex portion can be used to accommodate more free electrolyte, so the cycle capacity retention rate of the secondary battery is higher.

[0100] Compared with Examples 12-13, the width W of the first convex portion of Examples 1, 8-11 satisfies: 0.1W 0 ≤W≤0.9W 0 , which improves the structural strength and deformation resistance of the first wall, so the drop test pass rate of the secondary battery is higher.

[0101] Compared with Examples 18-19, the length L of the first protrusion of Examples 1, 14-17 satisfies: 0.1L 0≤L≤0.9L 0 , which improves the structural strength and deformation resistance of the first wall, so the drop test pass rate of the secondary battery is higher.

[0102] Compared with Examples 25-26, the height h1 of the first protrusion of Examples 1, 20-24 satisfies: 0.1 mm

[0103] The above disclosure is only a preferred implementation mode of the present application, and certainly cannot be used to limit the present application. Therefore, equivalent changes made according to the present application are still within the scope covered by the present application.​

Claims

1. An electrochemical device, comprising a packaging bag, an electrode assembly and a conductive plate, wherein the electrode assembly is arranged in the packaging bag, and the conductive plate is electrically connected to the electrode assembly, wherein: The packaging bag comprises a receiving portion for receiving the electrode assembly and a sealing portion connected to the receiving portion, and the conductive plate extends out of the packaging bag from the sealing portion; The first direction is the thickness direction of the electrode assembly, the second direction is perpendicular to the first direction and is the direction in which the conductive plate protrudes from the electrode assembly, and the accommodating portion includes a first wall and a second wall that are oppositely arranged along the second direction; The accommodating portion also includes a reinforcing portion, which includes at least one first protrusion integrally arranged on the first wall, and the first wall includes a first surface and a second surface arranged opposite to each other along the second direction, and the first protrusion forms a first protrusion on the first surface and a first recess on the second surface. When observed from the second direction, the first protrusion and the first recess formed by the first protrusion overlap.

2. The electrochemical device according to claim 1, wherein The first protrusion protrudes from the first wall in a direction away from the electrode assembly.

3. The electrochemical device according to claim 1, wherein The sealing portion is connected to the second wall.

4. The electrochemical device according to claim 3, wherein: The reinforcing portion also includes at least one second protrusion integrally arranged on the second wall, the second wall includes a third surface and a fourth surface arranged opposite to each other along the second direction, the second protrusion forms a second protrusion on the third surface and a second depression on the fourth surface, and when observed from the second direction, the second protrusion and the second depression formed by the second protrusion overlap.

5. The electrochemical device according to claim 4, wherein: The sealing portion includes a first connecting edge integrally connected to the accommodating portion, the second wall includes a first area and a second area respectively connected to the first connecting edge, the first area and the second area are respectively located on both sides of the first connecting edge along the first direction; along the first direction, the width of the first area is greater than the width of the second area; the at least one second protrusion is arranged in the first area.

6. The electrochemical device according to any one of claims 1 to 5, wherein: When viewed from the second direction, the reinforcement portion is strip-shaped; an angle α is included between an extension direction of the reinforcement portion and a third direction, 45°≤α≤90°, and the third direction is perpendicular to the first direction and the second direction, respectively.

7. The electrochemical device according to claim 6, wherein: A width of the reinforcing portion along the third direction is W, a dimension of the first wall or the second wall along the third direction is W0, and 0.1W0≤W≤0.9W0.

8. The electrochemical device according to claim 7, wherein: 0.5mm≤W≤95mm.

9. The electrochemical device according to claim 6, wherein: The distance between two adjacent reinforcing parts on the first wall or the second wall along the third direction is D, and the size of the first wall or the second wall along the third direction is W0, 0.1W0≤D≤0.9W0.

10. The electrochemical device according to claim 6, wherein: The length of the reinforcement portion is L, and the dimension of the first wall or the second wall along the first direction is L0, 0.1L0≤L≤0.9L0.

11. The electrochemical device according to claim 10, wherein: 1mm≤L≤15mm.

12. The electrochemical device according to any one of claims 1 to 5, wherein: The protruding height of the reinforcement portion is h1, 0.1≤h1≤2mm.

13. An electronic device, comprising a storage compartment, wherein: The electronic device further comprises an electrochemical device as claimed in any one of claims 1 to 13, wherein the electrochemical device is disposed in the containing chamber.

14. A method for preparing an electrochemical device according to any one of claims 1 to 12, wherein: The steps include: Providing a multi-layer packaging material, the multi-layer packaging material includes a first packaging film and a second packaging film, the first packaging film includes a first main body area and a first edge area connected to each other, and the second packaging film includes a second main body area and a second edge area connected to each other; At least the first main body area is stamped and formed by a forming mold, the forming mold includes a male mold and a female mold arranged opposite to each other, the male mold includes a first forming body, the female mold includes a second forming body, a forming part is protrudingly provided on the first forming body or the second forming body, the first forming body and the second forming body cooperate to form a groove on the first main body area, and the forming part forms the reinforcing part on the inner wall of the groove; electrically connecting the electrode assembly to the conductive plate, and placing the electrode assembly with the conductive plate in the groove; as well as The first packaging film and the second packaging film are placed opposite to each other, and the first edge area and the second edge area are packaged to form the sealing part, the conductive plate extends out of the packaging bag from the sealing part, and the second main body area and the first main body area with the groove form the accommodating part.

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