Electrochemical device and electronic device

Abstract

An electrochemical device includes a housing, an electrode assembly, and a conductive plate. The electrode assembly is disposed within the housing. The conductive plate is electrically connected to the electrode assembly and extends out of the housing. The electrochemical device further includes a first layer. Defining the extending direction of the conductive plate as the first direction, in the first direction, the first layer includes a connected first region and a second region, the first region is disposed within the housing, and the second region is disposed outside the housing. Defining the direction perpendicular to one surface of the conductive plate as the second direction, when observed along the second direction, the second region partially overlaps the conductive plate. The second region includes a first convex portion and a second convex portion. When observed along the second direction, the first convex portion partially overlaps the conductive plate and protrudes along the first direction, and the second convex portion partially overlaps the conductive plate and protrudes along the first direction. In the third direction, the first convex portion and the second convex portion are separated from each other. The present application also provides an electronic device. The present application has improved sealing performance and service life.

Description

Technical Field

[0001] This application relates to the field of energy storage technologies, and in particular, to an electrochemical device and an electronic device having the electrochemical device. Background Art

[0002] Electrochemical devices (such as batteries) are widely used in electronic products such as electronic mobile devices, power tools, and electric vehicles, and people's requirements for electrochemical devices are also getting higher and higher.

[0003] During the preparation of an electrochemical device, it is necessary to seal an upper housing and a lower housing to form a receiving space for receiving an electrode assembly and an electrolyte, and a conductive plate electrically connected to the electrode assembly extends out of the housing. However, there may be a problem of decreased airtightness at the position where the housing extends out the conductive plate. When mechanical abuse (drop, collision, vibration) occurs, there is a possibility of liquid leakage from the housing, reducing the service life of the product. Summary of the Invention

[0004] In view of the deficiencies in the prior art, it is necessary to provide an electrochemical device with improved airtightness.

[0005] In addition, it is also necessary to provide an electronic device having the electrochemical device.

[0006] This application provides an electrochemical device, including a housing, an electrode assembly, and a first conductive plate. The electrode assembly is disposed in the housing, and the first conductive plate is electrically connected to the electrode assembly and extends out of the housing. The electrochemical device further includes a first layer. Defining the extending direction of the first conductive plate as a first direction, in the first direction, the first layer includes a connected first region and a second region, the first region is disposed in the housing, and the second region is disposed outside the housing. Defining the direction perpendicular to one surface of the first conductive plate as a second direction, when observed along the second direction, the second region partially overlaps with the first conductive plate. The first layer includes an insulating material. The second region includes a first convex portion and a second convex portion. When observed along the second direction, the first convex portion partially overlaps with the first conductive plate and protrudes along the first direction, and the second convex portion partially overlaps with the first conductive plate and protrudes along the first direction. Defining that a third direction, the first direction, and the second direction are perpendicular to each other, in the third direction, the first convex portion is separated from the second convex portion.

[0007] In this application, a first convex portion and a second convex portion are provided on the first layer. When mechanical abuse occurs, the stress generated in the first layer can be dispersed along the extending directions of the first convex portion and the second convex portion. This is not only beneficial to reducing the possibility of the separation between the first layer and the first conductive plate, improving the sealing performance of the first layer, and thus increasing the service life of the electrochemical device. At the same time, it is also beneficial to reducing the possibility of the dissolution of transition metal ions in the positive electrode conductive layer due to the decrease in the sealing performance of the first layer and the entry of water vapor into the housing, improving the storage performance and cycling performance of the electrochemical device. Moreover, the first convex portion and the second convex portion increase the contact area between the first layer and the first conductive plate. Therefore, when the first conductive plate generates heat during charging, the first convex portion and the second convex portion improve the heat dissipation efficiency of the first layer, thereby improving the situation where the first layer deteriorates due to frequent temperature changes, and also being beneficial to improving the sealing performance of the first layer.

[0008] In some possible implementation manners, when observing along the second direction, the second region further includes a third convex portion provided between the first convex portion and the second convex portion, and the third convex portion protrudes along the first direction. The third convex portion further increases the contact area between the first layer and the first conductive plate. Therefore, it further improves the heat dissipation efficiency of the first layer, thereby improving the sealing performance of the first layer.

[0009] In some possible implementation manners, when observing along the second direction, the housing includes a first side provided between the first region and the second region. In the first direction, the distance from the first side to the vertex of the first convex portion is defined as a first distance, and the distance from the first side to the vertex of the third convex portion is defined as a second distance, and the first distance is greater than the second distance. Therefore, the first convex portion can better play the role of stress dispersion and heat dissipation improvement, and at the same time, it is also beneficial to improving the situation where the thickness of the first region connected to the surface of the first conductive plate is relatively small due to the relatively large protruding distance of the third convex portion, thereby reducing the influence on the sealing performance of the first layer.

[0010] In some possible implementation manners, the number of the third convex portions is multiple.

[0011] In some possible implementation manners, when observing along the second direction, the overlapping portion of the second region and the first conductive plate is defined as an overlapping area. The overlapping area includes a fourth convex portion that protrudes along the second direction. Therefore, when the first conductive plate needs to be bent, the fourth convex portion can reduce the possibility of short circuit or corrosion caused by the direct contact between the first conductive plate and the metal layer exposed from the edge of the first side.

[0012] In some possible implementations, the first layer includes a second side, and the second side extends in a third direction. In the third direction, the first convex portion is disposed between the second side and the second convex portion. In the first direction, the distance from the first side to the second side is a third distance, and the first distance is greater than the third distance. Therefore, the first convex portion can better play a role in stress dispersion and improving the heat dissipation effect. At the same time, it also improves the situation where the thickness of the first region connected to the side surface of the first conductive plate is correspondingly smaller when the extension distance of the first side is relatively large, thereby reducing the impact on the sealing performance of the first layer.

[0013] In some possible implementations, the second distance is greater than the third distance.

[0014] In some possible implementations, the third distance is from 0.2 mm to 3.5 mm, and the ratio range of the first distance to the third distance is from 1.09 to 16. By limiting the range of the third distance in this application, the possibility of reducing the sealing performance of the first layer due to a relatively small extension distance of the first side (insufficient pressure exerted by the encapsulation head on the first layer) is reduced. At the same time, the impact on the sealing performance of the first layer when the extension distance of the first side is relatively large is also reduced. By limiting the upper limit value of the third distance, the possibility of the first layer cracking after bending can also be reduced. At the same time, by limiting the ratio range of the first distance to the third distance in this application, the problems of reduced stress dispersion effect and heat dissipation effect when the first distance is relatively small are improved, and the impact on the energy density of the electrochemical device when the first distance is relatively large is also reduced.

[0015] In some possible implementations, when viewed from the second direction, the first conductive plate includes a first side surface and a second side surface that are oppositely arranged. In the first direction, the vertex of the first convex portion overlaps with the first side surface, and the vertex of the second convex portion overlaps with the second side surface.

[0016] In some possible implementations, the housing includes a main body portion and a connecting portion connecting the main body portion, and the connecting portion is used to seal the main body portion. The electrode assembly is disposed in the main body portion. The first conductive plate is electrically connected to the electrode assembly and extends out from the connecting portion. The first region connects the first conductive plate and the connecting portion. Therefore, the first region can be used to seal the gap between the first conductive plate and the connecting portion, reducing the possibility of liquid leakage.

[0017] In some possible implementations, the housing includes a first housing and a second housing that are oppositely arranged. The first housing includes a first polymer layer, and the second housing includes a second polymer layer. The first polymer layer and the second polymer layer are adhesively bonded to form a connecting portion, thereby achieving sealing. Moreover, the first polymer layer and the second polymer layer can also reduce the possibility of the housing being dissolved or swollen by the organic solvent in the electrolyte.

[0018] In some possible implementation manners, the first polymer layer includes a first polymer material, the second polymer layer includes a second polymer material, and the first polymer material and the second polymer material are each independently selected from at least one of polypropylene, propylene copolymer, polyethylene, or polymethyl methacrylate.

[0019] In some possible implementation manners, the first layer further includes a third region. In a first direction, the first region is connected between the second region and the third region, and the third region is disposed within the main body portion. The third region includes a fifth protrusion and a sixth protrusion. When observed in a second direction, the fifth protrusion partially overlaps with the first conductive plate and protrudes away from the first direction, and the sixth protrusion partially overlaps with the first conductive plate and protrudes away from the first direction. In a third direction, the fifth protrusion and the sixth protrusion are separated from each other. Therefore, when mechanical abuse occurs, the fifth protrusion and the sixth protrusion can disperse the stress generated in the first layer, and can improve the heat dissipation efficiency of the first layer, thereby improving the sealing performance of the first layer.

[0020] In some possible implementation manners, the insulating material is selected from at least one of polypropylene, polyethylene, polyethylene terephthalate, polyethylene naphthalate, polypropylene modified material, or polyethylene modified material.

[0021] This application further provides an electronic device, including the above-mentioned electrochemical device. Description of the Drawings

[0022] Figure 1 It is a perspective view of the electrochemical device provided by an embodiment of this application.

[0023] Figure 2 It is Figure 1 the front view of the electrochemical device shown.

[0024] Figure 3 It is Figure 1 the rear view of the electrochemical device shown.

[0025] Figure 4 It is Figure 2 the partial enlarged view of the electrochemical device shown at A.

[0026] Figure 5 It is Figure 2 the sectional view of the electrochemical device shown along V-V.

[0027] Figure 6 It is Figure 2 the sectional view of the electrochemical device shown along VI-VI.

[0028] Figure 7 It is Figure 2 the sectional view of the electrochemical device shown in some other embodiments.

[0029] Figure 8 The Figure 5 cross-sectional view after the first conductive plate of the electrochemical device shown is connected to the circuit board.

[0030] Figure 9A The Figure 2 cross-sectional view of the electrochemical device shown along VIII-VIII.

[0031] Figure 9B The Figure 2 structural schematic diagram of the first layer of the electrochemical device shown.

[0032] Figure 10 The Figure 2 top view of the electrode assembly of the electrochemical device in some embodiments.

[0033] Figure 11 The Figure 1 structural schematic diagram of the electrochemical device shown before sealing.

[0034] Figure 12 The Figure 11 partial cross-sectional view of the first housing of the electrochemical device shown.

[0035] Figure 13 The Figure 11 partial cross-sectional view of the second housing of the electrochemical device shown.

[0036] Figure 14 front view of the electrochemical device provided in another embodiment of the present application.

[0037] Figure 15 The Figure 14 partial enlarged view of the electrochemical device shown at B.

[0038] Figure 16 structural schematic diagram of the electronic device provided in one embodiment of the present application.

[0039] Description of main component symbols

[0040] Electronic device 1

[0041] Housing 10

[0042] Main body portion 11

[0043] Connection portion 12

[0044] First connection area 12a

[0045] Second connection area 12b

[0046] Third connection area 12c

[0047] Electrode assembly 20

[0048] The first pole piece 21

[0049] The second pole piece 22

[0050] The separator 23

[0051] The first tab 24

[0052] The second tab 25

[0053] The first conductive plate 30

[0054] The first conductive region 31

[0055] The second conductive region 32

[0056] The third conductive region 33

[0057] The second conductive plate 40

[0058] The first layer 50

[0059] The base material 50a

[0060] The first adhesive layer 50b

[0061] The second adhesive layer 50c

[0062] The first region 51

[0063] The second region 52

[0064] The third region 53

[0065] The second side 54

[0066] The second layer 60

[0067] The circuit board 70

[0068] The first electrical connector 71

[0069] The bonding member 72

[0070] The electrochemical device 100, 200

[0071] The first housing 101

[0072] The first part 101a

[0073] The second part 101b

[0074] The second housing 102

[0075] The third part 102a

[0076] The fourth part 102b

[0077] The first end wall 111

[0078] Second end wall 112

[0079] First side wall 113

[0080] Second side wall 114

[0081] Third side wall 115

[0082] Fourth side wall 116

[0083] First edge 121

[0084] First conductive layer 210

[0085] First conductive material layer 211

[0086] Second conductive layer 220

[0087] Second conductive material layer 221

[0088] First adapter 240

[0089] Second adapter 250

[0090] First included angle area 300

[0091] First surface 301

[0092] Second surface 302

[0093] First side 303

[0094] Second side 304

[0095] First segment 331

[0096] Second segment 332

[0097] Third segment 333

[0098] Second included angle area 500

[0099] First end edge 501

[0100] Second end edge 502

[0101] Third end edge 503

[0102] Fourth end edge 504

[0103] Overlap area 520

[0104] First convex part 521

[0105] Second convex part 522

[0106] Third convex part 523

[0107] Fourth convex part 524

[0108] Fifth convex part 531

[0109] Sixth convex part 532

[0110] First protective layer 1011

[0111] First metal layer 1012

[0112] First polymer layer 1013

[0113] Second protective layer 1021

[0114] Second metal layer 1022

[0115] Second polymer layer 1023

[0116] First end face 1111

[0117] Second end face 1121

[0118] Third end face 1112

[0119] Fourth end face 1122

[0120] First side surface 1131

[0121] Second side surface 1141

[0122] Third side surface 1132

[0123] Fourth side surface 1142

[0124] First direction X

[0125] Second direction Y

[0126] Third direction Z

[0127] First distance H1

[0128] Second distance H2

[0129] Third distance H3

[0130] Fourth distance H4

[0131] Vertices T1, T2, T3

[0132] The following specific embodiments will further illustrate the present application in combination with the above-mentioned drawings. Specific embodiments

[0133] The technical solutions in the embodiments of the present application will be described clearly and in detail below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs. 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.

[0134] 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 limited to the exemplary embodiments set forth herein. Rather, these exemplary embodiments are provided so that the present application will be thorough and detailed and will convey to those skilled in the art.

[0135] In addition, for the sake of brevity and clarity, in the drawings, the dimensions or thicknesses of various components and layers may be enlarged. Throughout the text, the same numerical values refer to the same elements. As used herein, the terms "and / or", "as well as / or" include any and all combinations of one or more of the associated listed items. In addition, it should be understood that when element A is referred to as being "connected" to element B, element A may be directly connected to element B, or there may be an intermediate element C and elements A and B may be indirectly connected to each other.

[0136] Furthermore, when describing the embodiments of the present application, "may" means "one or more embodiments of the present application".

[0137] The professional 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 forms are also intended to include the plural forms unless the context clearly indicates otherwise. It should be further understood that the term "comprising", when used in this specification, means the presence of the recited features, values, steps, operations, elements, and / or components, but does not preclude the presence or addition of one or more other features, values, steps, operations, elements, components, and / or combinations thereof.

[0138] Spatial-related terms, such as "upper" and the like, may be used in this document for convenience of description to describe the relationship between an element or feature and another element(s) or feature(s) as illustrated in the figures. It should be understood that, in addition to the directions described in the figures, spatial-related terms are intended to include different directions of the device or apparatus during use or operation. For example, if the device in the figure is flipped, an element described as "above" or "on" another element or feature will be oriented "below" or "beneath" the other element or feature. Thus, the exemplary term "upper" can include both upward and downward directions. It should be understood that although terms such as first, second, third, etc. may be used in this document 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 one element, component, region, layer, or part from another element, component, region, layer, or part. Thus, 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 teachings of the exemplary embodiments.

[0139] Please refer to Figures 1 to 3 , an embodiment of the present application provides an electrochemical device 100, including a housing 10, an electrode assembly 20, a first conductive plate 30, and a second conductive plate 40. The electrode assembly 20 is disposed within the housing 10. Both the first conductive plate 30 and the second conductive plate 40 are electrically connected to the electrode assembly 20 and extend out of the housing 10. The first conductive plate 30 and the second conductive plate 40 can be connected to external components (not shown in the figure). The first direction X, the second direction Y, and the third direction Z are defined to be perpendicular to each other. The extending direction of the first conductive plate 30 is the first direction X. The direction perpendicular to the first surface of the first conductive plate 30 is the second direction Y. The direction from the first conductive plate 30 to the second conductive plate 40 is the third direction Z.

[0140] Please also refer to Figure 5 , the housing 10 includes a first housing 101 and a second housing 102 that are oppositely disposed in the second direction Y. The first housing 101 includes a first part 101a and a second part 101b that are connected to each other. Three sides of the second part 101b are surrounded by the first part 101a. The second housing 102 includes a third part 102a and a fourth part 102b that are connected to each other. Three sides of the fourth part 102b are surrounded by the third part 102a. The first part 101a is connected to the third part 102a. The second part 101b and the fourth part 102b together form an accommodation space for accommodating the electrode assembly 20.

[0141] The housing 10 includes a main body portion 11 and a connecting portion 12. The second portion 101b of the first housing 101 and the fourth portion 102b of the second housing 102 are connected to form the main body portion 11. The first portion 101a of the first housing 101 and the third portion 102a of the second housing 102 are connected to form the connecting portion 12, and the connecting portion 12 is used to seal the main body portion 11. The electrode assembly 20 is disposed within the main body portion 11. In some embodiments, the housing 10 may be a packaging bag obtained by encapsulating with a packaging film, that is, the electrochemical device 100 is a soft-pack battery. That is, the connecting portion 12 is a sealing edge formed after the first portion 101a and the third portion 102a are encapsulated. The first conductive plate 30 and the second conductive plate 40 are both clamped in the connecting portion 12 and extend out of the housing 10 from the edge of the connecting portion 12.

[0142] Such as Figures 1 to 3As shown, in the first direction X, the main body portion 11 includes a first end wall 111 and a second end wall 112 that are oppositely arranged. In some embodiments, in the first direction X, the second portion 101b of the first housing 101 includes a first end face 1111 and a second end face 1121 that are oppositely arranged, and the fourth portion 102b of the second housing 102 includes a third end face 1112 and a fourth end face 1122 that are oppositely arranged. In the second direction Y, the first end face 1111 and the third end face 1112 are connected to form the first end wall 111, and the second end face 1121 and the fourth end face 1122 are connected to form the second end wall 112. In the third direction Z, the main body portion 11 includes a first side wall 113 and a second side wall 114 that are oppositely arranged. In some embodiments, in the third direction Z, the second portion 101b of the first housing 101 includes a first side surface 1131 and a second side surface 1141 that are oppositely arranged, and the fourth portion 102b of the second housing 102 includes a third side surface 1132 and a fourth side surface 1142 that are oppositely arranged. In the second direction Y, the first side surface 1131 and the third side surface 1132 are connected to form the first side wall 113, and the second side surface 1141 and the fourth side surface 1142 are connected to form the second side wall 114. In the second direction Y, the main body portion 11 includes a third side wall 115 and a fourth side wall 116 that are oppositely arranged. In some embodiments, the connecting portion 12 includes a connected first connecting region 12a, a second connecting region 12b, and a third connecting region 12c. When observed in the second direction Y, the first connecting region 12a of the connecting portion 12 is connected to the first end wall 111. At this time, the first conductive plate 30 and the second conductive plate 40 are both clamped in the first connecting region 12a and extend out of the housing 10 from the edge of the first connecting region 12a. When observed in the second direction Y, the second connecting region 12b is connected to the first side wall 113, and the third connecting region 12c is connected to the second side wall 114. Further, when observed from the second direction Y, the housing 10 includes a first side 121, and the first side 121 is also the edge of the first connecting region 12a in the first direction X. The first conductive plate 30 and the second conductive plate 40 extend out of the housing 10 from the first side 121. More specifically, the first end face 1111 and the third end face 1112 are respectively located on both sides of the first connecting region 12a. In the second direction Y, the first end face 1111 is connected to the first connecting region 12a and the third side wall 115, and the third end face 1112 is connected to the first connecting region 12a and the fourth side wall 116. Please refer to Figures 5 to 7 , in some embodiments, in the second direction Y, the distance between the first connecting region 12a and the third side wall 115 is greater than the distance between the first connecting region 12a and the fourth side wall 116, that is, the first end face 1111 is a deep pit surface and the third end face 1112 is a shallow pit surface.

[0143] In some embodiments, the first connection area 12a does not need to be bent, that is, the surface of the first connection area 12a can be substantially perpendicular to the surface of the first end wall 111. At this time, the first direction X is the direction in which the first conductive plate 30 extends out of the electrode assembly 20 (the direction in which the first conductive plate 30 protrudes from the electrode assembly 20), and is also the direction in which the first conductive plate 30 extends in the first connection area 12a. The second direction Y is a direction perpendicular to the first surface of the first conductive plate 30 located in the first connection area 12a.

[0144] In other embodiments, the first connection area 12a may also be bent onto the first end wall 111, thereby reducing the size of the electrochemical device 100 in the first direction X, improving space utilization and energy density. When the first connection area 12a is bent onto the first end wall 111, the direction in which the first conductive plate 30 extends in the first connection area 12a changes. At this time, the first direction X is the direction in which the first conductive plate 30 protrudes from the electrode assembly 20, and is also the direction in which the first conductive plate 30 extends in the first connection area 12a when the first connection area 12a is folded back to a state perpendicular to the first end wall 111. The second direction Y is the direction perpendicular to the first surface of the first conductive plate 30 located in the first connection area 12a when the first connection area 12a is folded back to a state perpendicular to the first end wall 111.

[0145] Please refer to Figure 5 , Figure 6 and Figure 10 The electrode assembly 20 is a winding structure, which includes a first electrode sheet 21, a second electrode sheet 22 and a separator 23, and the separator 23 is disposed between the first electrode sheet 21 and the second electrode sheet 22. The first electrode sheet 21, the separator 23 and the second electrode sheet 22 are stacked and wound in sequence to form the electrode assembly 20. The first electrode sheet 21 includes a first conductive layer 210 and a first conductive material layer 211 disposed on the first conductive layer 210. The second electrode sheet 22 includes a second conductive layer 220 and a second conductive material layer 221 disposed on the second conductive layer 220. The electrode assembly 20 also includes a plurality of first pole tabs 24 and a plurality of second pole tabs 25. One end of the plurality of first pole tabs 24 is electrically connected to the first conductive layer 210, and the other end is electrically connected to the first conductive plate 30. One end of the second pole tab 25 is electrically connected to the second conductive layer 220, and the other end is electrically connected to the second conductive plate 40. The plurality of first pole tabs 24 can be connected to the first conductive plate 30 through the first transition portion 240. The plurality of second tabs 25 may also be connected to the second conductive plate 40 via the second transition portion 250. Figure 7 , and Figure 5The difference of the electrode assembly 20 shown is that when the electrode assembly 20 is a wound structure, the electrode assembly 20 may not include the first pole ear 24 and the second pole ear 25. At this time, the first conductive plate 30 can be directly connected to the first conductive layer 210, and the second conductive plate 40 can also be directly connected to the second conductive layer 220. In some other embodiments, the electrode assembly 20 can also be a laminated structure, that is, the first electrode sheet 21, the separator 23 and the second electrode sheet 22 are laminated in sequence to form the electrode assembly 20.

[0146] Among them, the first electrode sheet 21 can be a positive electrode sheet. Correspondingly, the first conductive layer 210 can be a positive conductive layer, and the first conductive material layer 211 can be a positive conductive material layer. The first conductive layer 210 can have the function of collecting current. The second electrode sheet 22 can be a negative electrode sheet. Correspondingly, the second conductive layer 220 can be a negative conductive layer, and the second conductive material layer 221 can be a negative active material layer. The second conductive layer 220 can have the function of collecting current.

[0147] The positive conductive layer can be made of aluminum foil or nickel foil, and the negative conductive layer can be made of at least one of copper foil, nickel foil or carbon-based conductive layer. The positive conductive material layer contains a positive active substance, and the positive active substance includes a compound that can reversibly intercalate and deintercalate lithium ions (i.e., a lithiated intercalation compound). The negative conductive material layer contains a negative active substance, that is, a negative active substance that can reversibly deintercalate active ions. The separator 23 includes at least one of polyethylene, polypropylene, polyvinylidene fluoride, polyethylene terephthalate, polyimide or aramid.

[0148] As Figures 1 to 4 、 Figure 9A shown, the electrochemical device 100 further includes a first layer 50, and the first layer 50 includes an insulating material. The first layer 50 can be used to seal and connect the first conductive plate 30 to the housing 10, and can also keep the first conductive plate 30 and the housing 10 electrically insulated. Specifically, the first layer 50 fills the possible gap between the first conductive plate 30 and the connecting portion 12, thereby sealing and connecting the first conductive plate 30 to the housing 10, and reducing the possibility of separation between the first conductive plate 30 and the connecting portion 12 during subsequent use. In some embodiments, the insulating material of the first layer 50 is selected from at least one of polypropylene, polyethylene, polyethylene terephthalate, polyethylene naphthalate, polypropylene modified material or polyethylene modified material.

[0149] Please refer to Figure 9B, the first layer 50 can be formed by stacking one or more layers of materials along the second direction Y. In some embodiments, the first layer 50 is formed by stacking three layers of materials, including a base material 50a, a first adhesive layer 50b, and a second adhesive layer 50c. The base material 50a is disposed between the first adhesive layer 50b and the second adhesive layer 50c. The materials of the base material 50a, the first adhesive layer 50b, and the second adhesive layer 50c are each independently selected from at least one of polypropylene, polyethylene, polyethylene terephthalate, polyethylene naphthalate, polypropylene modified materials, or polyethylene modified materials. The melting point of the base material 50a can be higher than the melting point of the first adhesive layer 50b and can also be higher than the melting point of the second adhesive layer 50c. With reference to Figure 9A and Figure 9B , one surface of the first adhesive layer 50b is bonded to the first conductive plate 30, and the other surface is bonded to the base material 50a. The second adhesive layer 50c has a fused portion with the first portion 101a of the first housing 101 or the third portion 102a of the second housing 102.

[0150] Please refer to Figure 9A , wherein the first conductive plate 30 includes a first surface 301, a second surface 302, a first side surface 303, and a second side surface 304. In the second direction Y, the first surface 301 and the second surface 302 are disposed opposite to each other. Please refer to Figure 2 and Figure 3 together, the first surface 301 faces the first housing 101, and the second surface 302 faces the second housing 102. In the third direction Z, the first side surface 303 and the second side surface 304 are disposed opposite to each other. The first side surface 303 is connected between the first surface 301 and the second surface 302, and the second side surface 304 is connected between the first surface 301 and the second surface 302. Four first included angle regions 300 are formed between the first surface 301 and the first side surface 303, between the second surface 302 and the first side surface 303, between the first surface 301 and the second side surface 304, and between the second surface 302 and the second side surface 304. In some embodiments, the first included angle region 300 can be approximately 90 degrees. The first layer 50 covers the first surface 301, the second surface 302, the first side surface 303, and the second side surface 304 of the first conductive plate 30 respectively, so as to hermetically connect the above-mentioned respective surfaces of the first conductive plate 30 to the housing 10. Therefore, when observed from the opposite direction of the first direction X, the first layer 50 includes four second included angle regions 500. The four second included angle regions 500 are respectively connected to the four first included angle regions 300 of the first conductive plate 30.

[0151] Please refer to Figure 4 and Figure 5, the first conductive plate 30 includes a connected first conductive region 31, a second conductive region 32, and a third conductive region 33. The first conductive region 31 and the third conductive region 33 are located within the housing 10, that is, when viewed from the second direction Y, both the first conductive region 31 and the third conductive region 33 overlap with the housing 10. For example, when viewed from the second direction Y, the first conductive region 31 overlaps with the first part 101a, and the third conductive region 33 overlaps with the second part 101b. The first conductive region 31 is used for electrically connecting with the first tab 24 of the electrode assembly 20. The second conductive region 32 extends out of the housing 10.

[0152] For example Figure 4 As shown, in the first direction X, the first layer 50 includes a connected first region 51 and a second region 52. The first region 51 is disposed within the housing 10. When viewed along the second direction Y, the first side 121 is disposed between the first region 51 and the second region 52, and the first side 121 partially overlaps with the boundary line between the first region 51 and the second region 52. In some embodiments, the first region 51 is sandwiched within the connecting portion 12. Please refer to Figure 2 simultaneously. The first region 51 is the region where the orthographic projection of the first layer 50 along the second direction Y coincides with the first part 101a of the first housing 101 and is sandwiched between the first part 101a of the first housing 101 and the third part 102a of the second housing 102 in the second direction Y. The second region 52 is disposed outside the housing 10. The second region 52 is the region of the first layer 50 that is connected to the first region 51 and is farther from the second part 101b in the first direction X than the first part 101a of the first housing 101 when viewed along the second direction Y. When viewed along the second direction Y, the first region 51 partially overlaps with the first conductive plate 30. For example, the first region 51 may partially overlap with the first conductive region 31 of the first conductive plate 30; the second region 52 partially overlaps with the first conductive plate 30. For example, the second region 52 may partially overlap with the second conductive region 32 of the first conductive plate 30.

[0153] The first layer 50 may further include a third region 53. In the first direction X, the first region 51 is connected between the second region 52 and the third region 53. Please refer to Figure 2 and Figure 4 simultaneously. The third region 53 is the region of the first layer 50 that is connected to the first region 51 and is disposed within the main body portion 11. That is, the third region 53 is the region that is closer to the inside of the main body portion 11 in the first direction X than the first part 101a when viewed from the second direction Y. When viewed along the second direction Y, the third region 53 partially overlaps with the first conductive plate 30. For example, the third region 53 may partially overlap with the third conductive region 33 of the first conductive plate 30. Among them, when the head applies pressure to the connecting portion 12, a part of the first layer 50 can be squeezed towards the positions with smaller pressure on both sides after being pressed, thereby forming the second region 52 and the third region 53.

[0154] As Figure 4 shown, the second region 52 includes a first convex portion 521 and a second convex portion 522. When observed along the second direction Y, the first convex portion 521 partially overlaps with the first conductive plate 30 and protrudes along the first direction X, and the second convex portion 522 partially overlaps with the first conductive plate 30 and protrudes along the first direction X. Please refer to Figure 4 and Figure 9A together. The first convex portion 521 and the second convex portion 522 protrude from the second included angle region 500 along the first direction X. In the third direction Z, the first convex portion 521 is separated from the second convex portion 522. In the first direction X, the first convex portion 521 has a vertex T1, and the second convex portion 522 has a vertex T2. The vertex T1 is the farthest point of the first convex portion 521 from the first side 121, and the vertex T2 is the farthest point of the second convex portion 522 from the first side 121.

[0155] In the prior art, in the region where the first layer is connected to the first included angle region of the first conductive plate (i.e., the second included angle region), due to the sudden change in thickness and the position where the insulating material transitions to the metal material of the first conductive plate, the sealing strength is relatively low. When mechanical abuse occurs, stress concentration is more likely to occur in the second included angle region, causing the first layer to possibly separate from the first conductive plate at the second included angle region, reducing the sealing performance, resulting in liquid leakage or external moisture entering the interior of the housing, and affecting the service life of the electrochemical device. Moreover, due to the decrease in the sealing performance of the first layer, the water vapor entering the housing may cause an increase in the acid content inside the electrochemical device, accelerating the dissolution of transition metal ions in lithium cobaltate (e.g., accelerating the dissolution of cobalt ions in lithium cobaltate in the positive electrode conductive layer), affecting the storage performance and cycling performance of the electrochemical device. In addition, heat is generated at the first conductive plate during charging, especially more heat is generated at the first conductive plate during fast charging. Since the second included angle region is directly in contact with the first conductive plate, the insulating material at the second included angle region deteriorates due to frequent temperature changes during long-term charge and discharge processes, making the second included angle region more likely to generate cracks or reduce the sealing performance.

[0156] In the present application, a first convex portion 521 and a second convex portion 522 are provided on the first layer 50. When mechanical abuse occurs, the stress generated at the second included angle area 500 of the first layer 50 can be dispersed along the extending directions of the first convex portion 521 and the second convex portion 522. This is not only beneficial to reducing the possibility of separation between the second included angle area 500 and the first conductive plate 30, improving the sealing performance of the first layer 50, and thus increasing the service life of the electrochemical device 100. At the same time, it is also beneficial to reducing the possibility of dissolution of transition metal ions in the positive electrode conductive layer due to the decrease in the sealing performance of the first layer 50 and the entry of water vapor into the housing 10, improving the storage performance and cycling performance of the electrochemical device 100. Furthermore, the first convex portion 521 and the second convex portion 522 increase the contact area between the first layer 50 and the first conductive plate 30. Therefore, when the first conductive plate 30 generates heat during charging, the first convex portion 521 and the second convex portion 522 improve the heat dissipation efficiency of the first layer 50, thereby improving the situation where the first layer 50 deteriorates due to frequent temperature changes, and also being beneficial to improving the sealing performance of the first layer 50.

[0157] As Figure 4 shown, in some embodiments, when observed along the second direction Y, in the first direction X, the vertex T1 of the first convex portion 521 overlaps with the first side surface 303, and the vertex T2 of the second convex portion 522 overlaps with the second side surface 304.

[0158] As Figure 4As shown, in some embodiments, when observed along the second direction Y, the second region 52 further includes a third convex portion 523 disposed between the first convex portion 521 and the second convex portion 522, and the third convex portion 523 protrudes along the first direction X. Among them, when observed along the second direction Y, the overlapping portion of the second region 52 and the first conductive plate 30 is defined as the overlapping region 520. For example, the overlapping region 520 may be the overlapping portion of the second region 52 and the second conductive region 32 of the first conductive plate 30. The third convex portion 523 is located in the overlapping region 520. When observed along the second direction Y, the overlapping region 520 is also the portion of the second region 52 disposed between the first side surface 303 and the second side surface 304 of the first conductive plate 30. The third convex portion 523 has a vertex T3, and the vertex T3 is the farthest point of the third convex portion 523 from the first side 121. By providing the third convex portion 523, the contact area between the first layer 50 and the first conductive plate 30 is further increased. Therefore, when the first conductive plate 30 is charged and generates heat, the third convex portion 523 further improves the heat dissipation efficiency of the first layer 50, thereby improving the situation where the first layer 50 deteriorates due to frequent temperature changes, that is, improving the sealing performance of the first layer 50. In some specific embodiments, the number of the overlapping regions 520 is two. In the second direction Y, the two overlapping regions 520 are respectively located on both sides of the first conductive plate 30. One overlapping region 520 is connected to the first surface 301 of the first conductive plate 30, and the other overlapping region 520 is connected to the second surface 302 of the first conductive plate 30. Each overlapping region 520 is provided with a third convex portion 523.

[0159] In some embodiments, the number of the third convex portions 523 located on the first surface 301 may be multiple, and the multiple third convex portions 523 are connected along the third direction Z. The number of the third convex portions 523 located on the second surface 302 may also be multiple, and the multiple third convex portions 523 are connected along the third direction Z.

[0160] In the first direction X, the distance from the first side 121 to the vertex T1 of the first convex portion 521 is defined as the first distance H1, and the distance from the first side 121 to the vertex T3 of the third convex portion 523 is defined as the second distance H2. Then, in some embodiments, the first distance H1 is greater than the second distance H2 (H1 > H2). It can be understood that when the number of the third convex portions 523 located on the first surface 301 (or the second surface 302) is multiple, the second distance H2 can be the maximum value among the distances from the first side 121 to the vertices T3 of the multiple third convex portions 523. If the protruding distance of the third convex portion 523 is relatively large, it indicates that a larger part of the first region 51 connected to the first surface 301 or the second surface 302 of the first conductive plate 30 is extruded out of the connecting portion 12, resulting in a relatively small thickness of the first region 51 connected to the surface of the first conductive plate 30, and the sealing strength of the first layer 50 is also relatively small. Therefore, in this application, by setting H1 > H2, the first convex portion 521 can preferably play a role in dispersing stress and improving the heat dissipation effect, and also reduces the influence on the sealing strength of the first layer 50. Moreover, it is also beneficial to reduce the influence of the first layer 50 on the energy density of the electrochemical device 100. Additionally, the fourth distance H4 from the first side 121 to the vertex T2 of the second convex portion 522 can also be defined as greater than the second distance H2.

[0161] As Figure 4 shown, in some embodiments, when observed in the second direction Y, the first layer 50 includes a first end edge 501, a second end edge 502, a third end edge 503, and a fourth end edge 504. In the first direction X, the first end edge 501 and the second end edge 502 are oppositely arranged. When observed along the second direction Y, the first end edge 501 is located on the side of the first side 121 away from the first portion 101a, and the second end edge 502 overlaps with the first portion 101a. In the third direction Z, the third end edge 503 and the fourth end edge 504 are oppositely arranged, and the fourth end edge 504 is the edge of the first layer 50 closer to the second conductive plate 40. Both the third end edge 503 and the fourth end edge 504 extend along the first direction X. When observed along the second direction Y, the first convex portion 521, the second convex portion 522, and the third convex portion 523 are all formed on the first end edge 501.

[0162] Among them, the first end edge 501 includes a second edge 54, and the second edge 54 extends along the third direction Z. In the third direction Z, the first convex portion 521 is disposed between the second edge 54 and the second convex portion 522. In some embodiments, in the third direction Z, the second edge 54, the first convex portion 521, the third convex portion 523, and the second convex portion 522 are connected in sequence. In the first direction X, the distance from the first edge 121 to the second edge 54 is defined as the third distance H3, then the first distance H1 is greater than the third distance H3 (H1 > H3). By defining H1 > H3, the first convex portion 521 can better play the role of stress dispersion and improving the heat dissipation effect, and reduces the possibility that the thickness of the first region 51 connected to the side surface of the first conductive plate 30 is correspondingly small and the sealing performance is reduced due to the large protruding distance of the first edge 121. Moreover, it is also beneficial to reduce the influence of the first layer 50 on the energy density of the electrochemical device 100.

[0163] Further, the second distance H2 is greater than the third distance H3 (H2 > H3).

[0164] In some embodiments, the third distance H3 is 0.2 mm to 3.5 mm, and the ratio range of the first distance H1 to the third distance H3 is 1.09 to 16. By defining the range of the third distance H3 in this application, the possibility that the first edge 121 protrudes a small distance (the pressure applied by the encapsulation head on the first layer 50 is insufficient) resulting in a reduction in the sealing performance of the first layer 50 is reduced, and at the same time, the influence on the sealing performance of the first layer 50 when the first edge 121 protrudes a large distance is also reduced. Moreover, it can be understood that if the first conductive plate 30 exposed to the housing 10 needs to be bent toward the first end wall 111 side (for example, to facilitate the connection of the first conductive plate 30 to external components), when the first edge protrudes a large distance, the first layer needs to be bent simultaneously with the first conductive plate, and stress concentration may occur at the bending position during mechanical abuse, increasing the possibility of rupture of the first layer. Therefore, by defining the upper limit value of H3, the possibility of rupture of the first layer 50 after bending can also be reduced. At the same time, by defining the ratio range of the first distance H1 to the third distance H3 in this application, the problems of reduced stress dispersion effect and heat dissipation effect when H1 is small are improved, and at the same time, the influence on the energy density of the electrochemical device 100 when H1 is large is also reduced.

[0165] In some specific embodiments, the first distance H1 is 3 mm to 4.5 mm. The second distance H2 is 2.3 mm to 3 mm. The third distance H3 is 1.8 mm to 2.5 mm.

[0166] Similarly, the ratio range of the fourth distance H4 to the third distance H3 can be set to 1.09 to 16. In some specific embodiments, the fourth distance H4 is 3 mm to 4.5 mm.

[0167] Such as Figure 8As shown, in some embodiments, the electrochemical device 100 further includes a circuit board 70 electrically connected to the first conductive plate 30 and the second conductive plate 40. Specifically, the first conductive plate 30 is bent at the first end surface 1111 of the third conductive region 33 of the housing 10 exposed toward the first end wall 111, forming a first section 331 and a second section 332 oppositely arranged in the second direction Y, and a third section 333 connected between the first section 331 and the second section 332. The first section 331 is connected to the first conductive region 31. The circuit board 70 is disposed on the first end surface 1111. A first electrical connector 71 and a second electrical connector (not shown in the figure) are provided on the circuit board 70. The circuit board 70 is connected to the second section 332 of the third conductive region 33 through the first electrical connector 71. Similarly, the region of the second conductive plate 40 exposed from the housing 10 can also be bent toward the first end surface 1111 and connected to the second electrical connector. Among them, the first electrical connector 71 and the second electrical connector can be nickel sheets.

[0168] Further, in order to reduce the possibility that the third conductive region 33 opens in the opposite direction of the bending direction, an adhesive 72 can also be provided between the first section 331 and the second section 332. The two opposite surfaces of the adhesive 72 in the second direction Y are respectively adhered to the first section 331 and the second section 332.

[0169] In some embodiments, the materials of the first housing 101 and the second housing 102 can both be multi-layer sheets. As Figure 12 shown, the first housing 101 can include a first protective layer 1011, a first metal layer 1012, and a first polymer layer 1013 stacked in sequence. Compared with the first protective layer 1011, the first polymer layer 1013 is closer to the electrode assembly 20. The material of the first protective layer 1011 can be a polymer resin, which can be used to protect the first metal layer 1012, reduce the possibility of damage to the first metal layer 1012 due to external forces, and at the same time can delay the air penetration of the external environment and maintain a normal operating environment inside the electrochemical device 100. In some embodiments, the material of the first protective layer 1011 can be selected from at least one of polyethylene terephthalate, polybutylene terephthalate, polyvinylidene fluoride, polytetrafluoroethylene, polypropylene, polyamide, and polyimide. The first metal layer 1012 can be used to delay the moisture penetration of the external environment and reduce the damage caused by external forces to the electrode assembly 20. In some embodiments, the first metal layer 1012 can be an aluminum foil layer or a steel foil layer. The first polymer layer 1013 has the property of heating and melting, can be used for sealing, and can reduce the possibility of the multi-layer sheet being dissolved or swollen by the organic solvent in the electrolyte. The first polymer layer 1013 can also be used to reduce the possibility of the electrolyte in the electrolyte contacting the first metal layer 1012 and causing corrosion of the metal layer. In some embodiments, the first polymer layer 1013 includes a polymer material, which can be selected from at least one of polypropylene, propylene copolymer, polyethylene, and polymethyl methacrylate.

[0170] As shown Figure 13 in the figure, the second housing 102 may include a second protective layer 1021, a second metal layer 1022, and a second polymer layer 1023 that are stacked in sequence. It can be understood that when the first housing 101 and the second housing 102 can be obtained by folding a single encapsulation film, the materials of the second protective layer 1021, the second metal layer 1022, and the second polymer layer 1023 are exactly the same as those of the first protective layer 1011, the first metal layer 1012, and the first polymer layer 1013, respectively, and will not be described repeatedly here.

[0171] Please refer to Figures 11 to 13 simultaneously. When preparing the housing 10, a certain temperature and pressure can be applied to the first part 101a of the first housing 101 and the third part 102a of the second housing 102 by using the head of the encapsulation device, so that the first polymer layer 1013 and the second polymer layer 1023 are melted and bonded together to form the connecting portion 12. The first layer 50 is disposed between the first polymer layer 1013 and the second polymer layer 1023, and is melted and bonded together with the first polymer layer 1013 and the second polymer layer 1023 during sealing. In some embodiments, when the first layer 50 is stacked by three layers of materials, the second adhesive layer 50c of the first layer 50 is melted and bonded together with the first polymer layer 1013 and the second polymer layer 1023 during sealing. Among them, when forming the connecting portion 12 by sealing, the pressure applied by the head to the connecting portion 12 is relatively large, so that part of the first layer 50 is squeezed towards the position with relatively small pressure after being pressed, thereby forming the second region 52 and the third region 53. The first layer 50 fills the possible gap between the first conductive plate 30 and the connecting portion 12, and reduces the possibility of separation between the first conductive plate 30 and the connecting portion 12 during subsequent use. Moreover, since the materials of the first layer 50, the first polymer layer 1013, and the second polymer layer 1023 are all polymers and their melting points are relatively close, the bonding degree is better under the high-temperature and high-pressure environment, improving the sealing performance. The first layer 50 can also improve the electrical insulation between the first conductive plate 30 and the first metal layer 1012 and the second metal layer 1022, and reduce the possibility of short circuit caused by their contact.

[0172] Please refer to Figure 8 and Figure 9A again. As shown in the figure, in some embodiments, the overlapping area 520 may further include a fourth convex portion 524 that protrudes along the second direction Y. In the first direction X, the fourth convex portion 524 is located on one side of the first edge 121, so as to cover the exposed edge of the first edge 121. Therefore, when the third conductive region 33 of the first conductive plate 30 needs to be bent towards the first end wall 111 side, the fourth convex portion 524 can reduce the possibility of short circuit or corrosion caused by the direct contact between the first conductive plate 30 and the metal layer exposed from the edge of the first edge 121.

[0173] As Figures 1 to 4 shown, in some embodiments, the electrochemical device 100 may further include a second layer 60, and the second layer 60 includes an insulating material. The second layer 60 can be used to seal and connect the second conductive plate 40 and the housing 10, and can also electrically insulate the second conductive plate 40 and the housing 10. The second layer 60 can also adopt a design similar to that of the first layer 50, that is, protrusions are provided on the second layer 60, thereby further improving the sealing performance. No repeated description will be made here.

[0174] Please refer to Figure 14 and Figure 15 , another embodiment of the present application further provides an electrochemical device 200. The difference from the electrochemical device 100 is that the third region 53 includes a fifth protrusion 531 and a sixth protrusion 532. When observed along the second direction Y, the fifth protrusion 531 partially overlaps with the first conductive plate 30 and protrudes away from the first direction X, and the sixth protrusion 532 partially overlaps with the first conductive plate 30 and protrudes away from the first direction X. In some specific embodiments, the number of the fifth protrusions 531 is two, and the number of the sixth protrusions 532 is also two. The two fifth protrusions 531 and the two sixth protrusions 532 protrude away from the first direction X from the four second included angle regions 500 respectively. In the third direction Z, the fifth protrusion 531 and the sixth protrusion 532 are separated from each other.

[0175] Therefore, when mechanical abuse occurs, the stress generated by the first layer 50 at the second included angle region 500 can also be dispersed along the extending directions of the fifth protrusion 531 and the sixth protrusion 532. This is also beneficial to reducing the possibility of separation between the second included angle region 500 and the first conductive plate 30, improving the sealing performance of the first layer 50, and also beneficial to reducing the possibility of the first conductive plate 30 being broken when the stress is conducted to the first conductive plate 30, thereby improving the service life of the electrochemical device 200. Secondly, the fifth protrusion 531 and the sixth protrusion 532 also improve the heat dissipation efficiency of the first layer 50, thereby improving the sealing performance of the first layer 50.

[0176] Among them, the electrochemical device 100 (or the electrochemical device 200) of the present application includes all devices capable of undergoing electrochemical reactions. Specifically, the electrochemical device 100 includes all kinds of primary batteries, secondary batteries, fuel cells, solar cells, and capacitors (such as supercapacitors). Optionally, the electrochemical device 100 can be a lithium secondary battery, including a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, and a lithium ion polymer secondary battery.

[0177] Please refer to Figure 16 , an embodiment of the present application further provides an electronic device 1, and the electronic device 1 includes the electrochemical device 100 (or the electrochemical device 200).

[0178] Among them, the electrochemical device 100 of the present application is applicable to electronic devices 1 in various fields. In one embodiment, the electronic device 1 of the present application may 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, a liquid crystal TV, a portable cleaner, a portable CD player, a minidisc, a transceiver, an electronic notepad, a calculator, a memory card, a portable recorder, a radio, a backup power supply, a motor, an automobile, a motorcycle, a moped, a bicycle, a lighting fixture, a toy, a game console, a clock, a power tool, a flash, a camera, a large household battery, and a lithium-ion capacitor, etc.

[0179] The present application will be described in detail below through specific examples and comparative examples. Among them, taking the soft-pack battery as an example of the electrochemical device and combining the specific preparation process and test method to describe the present application. Those skilled in the art should understand that the preparation methods described in the present application are only examples, and any other suitable preparation methods are within the scope of the present application.

[0180] Example 1

[0181] (1) Preparation of the negative electrode plate: Mix the negative electrode active material artificial graphite, conductive carbon black (Super P), and styrene-butadiene rubber (SBR) according to a weight ratio of 96:1.5:2.5, add deionized water as a solvent, and formulate a slurry with a weight percentage of 70 wt%. Stir evenly. Coat the slurry evenly on one surface of a negative electrode current collector copper foil with a thickness of 10 μm, and dry it at 110 °C to obtain a negative electrode plate with a negative electrode active material layer coated on one side and a coating thickness of 150 μm. Repeat the above steps on the other surface of the negative electrode plate to obtain a negative electrode plate with a negative electrode active material layer coated on both sides. The negative electrode plate has a negative electrode tab, and the negative electrode tab is nickel (Ni).

[0182] (2) Preparation of the positive electrode plate: Mix the positive electrode active material lithium cobalt oxide (LiCoO2), conductive carbon black (Super P), and polyvinylidene fluoride (PVDF) according to a weight ratio of 97.5:1.0:1.5, add N-methylpyrrolidone (NMP) as a solvent, and formulate a slurry with a solid content of 75 wt%. Stir evenly. Coat the slurry evenly on one surface of a positive electrode current collector aluminum foil with a thickness of 12 μm, and dry it at 90 °C to obtain a positive electrode plate with a positive electrode active material layer thickness of 100 μm. Repeat the above steps on the other surface of the positive electrode current collector aluminum foil to obtain a positive electrode plate with a positive electrode active material layer coated on both sides. The positive electrode plate has a positive electrode tab, and the positive electrode tab is aluminum (Al).

[0183] (3) Preparation of electrolyte: In a dry argon atmosphere, first, organic solvents ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) are mixed at a mass ratio of EC:EMC:DEC = 30:50:20. Then, lithium salt lithium hexafluorophosphate (LiPF6) is added to the organic solvents and dissolved and mixed evenly to obtain an electrolyte with a lithium salt concentration of 1.15 mol / L.

[0184] (4) Preparation of battery: Connect the first layer to the first conductive plate and the second layer to the second conductive plate, and then weld the first conductive plate and the second conductive plate to the first tab and the second tab respectively. Among them, the order of the pasting process and the welding process can be exchanged. Then, stack and wind the first electrode sheet, the separator, and the second electrode sheet in sequence to obtain an electrode assembly. The separator is a polyethylene (PE) film with a thickness of 15 μm. Then, inject electrolyte, perform formation, and encapsulation to make a battery with dimensions of 5.40 mm × 94 mm × 90 mm, and bend and connect the circuit board to the areas where the first conductive plate and the second conductive plate extend out of the housing. After encapsulation, when observing along the second direction, a first convex part and a second convex part that partially overlap with the first conductive plate are formed on the first layer, and the second area of the first layer further includes a third convex part provided between the first convex part and the second convex part. The values of H1, H2, and H3 and the ratio of H1 / H3 refer to Table 1.

[0185] Comparative Example 1

[0186] The difference from Example 1 is that when observing along the second direction, a first convex part and a second convex part that partially overlap with the first conductive plate are not formed on the first layer, and a third convex part located between the first convex part and the second convex part is not formed either.

[0187] Comparative Examples 2 - 3 and Examples 2 - 5

[0188] The difference from Example 1 is that the values of H1, H2, and H3 and the ratio of H1 / H3 are different.

[0189] Then, drop tests, drop + high temperature and high humidity tests, high rate charge and discharge tests, and cobalt dissolution rate tests are respectively carried out on the batteries of each example and comparative example. 100 samples are taken from each of the examples and comparative examples for testing, and the corresponding test results are recorded in Table 1.

[0190] The steps of the drop test are as follows: 1) Under the environmental condition of 25°C, adjust the voltage of the battery to 100% SOC (State of Charge). 2) Place the battery in the fixture bin, and use an automatic drop device to drop the battery onto a steel plate from a position of 1.8 m at an angle of 45 ± 15 degrees in turn with the bottom surface, left side surface, right side surface, front surface, back surface, and top surface as one round of landing methods. A total of 14 rounds, that is, 84 times, are dropped in one cycle. 3) After the drop is completed, check that if there is no liquid leakage in the connection area between the first layer and the first conductive plate, and there are no cracks or fractures in the area where the first layer exposes the housing, it is determined that the battery passes the test.

[0191] The steps of the drop + high temperature and high humidity test are as follows: 1) Under the environmental condition of 25°C, adjust the voltage of the battery to 100% SOC (State of Charge). 2) After the drop is completed, place the battery in the fixture bin, and use an automatic drop device to drop the battery onto a steel plate from a position of 1.8 m at an angle of 45 ± 15 degrees in turn with the bottom surface, left side surface, right side surface, front surface, back surface, and top surface as one round of landing methods. A total of 14 rounds, that is, 84 times, are dropped in one cycle. 3) Place the battery in a heating furnace and store it for 30 days. The temperature in the furnace is 65°C, and the relative humidity is 90%. 4) Take out the battery, and check that if there is no liquid leakage in the connection area between the first layer and the first conductive plate, it is determined that the battery passes the test.

[0192] The steps of the high-rate charge and discharge test are as follows: 1) Charge at a constant current of 10.0C to 4.15V, and then charge at a constant voltage to 8C. 2) Charge at a constant current of 8.0C to 4.35V, and then charge at a constant voltage to 6C. 3) Charge at a constant current of 6.0C to 4.45V, and then charge at a constant voltage to 1C. 4) Charge at a constant current of 1.0C to 4.5V, and then charge at a constant voltage to 0.05C. 5) Discharge at 2C until the voltage reaches 3.0V. 6) During the cycling process, discharge at the 100th, 500th, and 1000th times respectively. Check that if there is no liquid leakage in the connection area between the first layer and the first conductive plate, it is determined that the battery passes the test.

[0193] The steps of the cobalt dissolution amount test are as follows: 1) After the battery completes the 1000th discharge, centrifuge the battery. 2) Perform ICP (Inductive Coupled Plasma Emission Spectrometer) test on the liquid obtained after centrifugation to obtain the cobalt content of the electrolyte, so as to characterize the cobalt dissolution amount of lithium cobaltate in the positive electrode sheet.

[0194] Table 1

[0195]

[0196] As can be seen from the data in Table 1, compared with Comparative Example 1, since the first layer of Example 1 is provided with the first convex portion, the second convex portion and the third convex portion, the first layer has improved sealing performance, so that the passing rates of the drop test, the drop + high temperature and high humidity test, and the high-rate charge and discharge test of the battery of Example 1 are all relatively high, and the cobalt ion dissolution amount is relatively low after long-term cycling.

[0197] When the first layer is provided with the first convex portion, the second convex portion and the third convex portion, the value of H3 and the ratio of H1 / H3 will further affect the sealing performance of the first layer. Compared with Example 2, in Comparative Example 2, H3 is too small and the ratio of H1 / H3 is too large, so the sealing performance of the first layer decreases relatively. After long-term cycling, the passing rate of the high-rate charge and discharge test decreases, and the cobalt ion dissolution amount also increases relatively. In Comparative Example 3, H3 is too large and the ratio of H1 / H3 is too small, and stress concentration is likely to occur at the bending position of the first conductive plate in the first layer, so the proportion of cracks or fractures increases.

[0198] Compared with Example 4, in Comparative Example 5, the ratio of H1 / H3 is too large, so the sealing performance of the first layer decreases relatively, the passing rate of the high-rate charge and discharge test decreases, and the cobalt ion dissolution amount also increases relatively after long-term cycling. In Examples 3-5, the values of H3 and the ratio of H1 / H3 meet the predetermined conditions, so the passing rates of the drop test, the drop + high temperature and high humidity test, and the high-rate charge and discharge test of the battery are all relatively high, and the cobalt ion dissolution amount is relatively low after long-term cycling.

[0199] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and not to limit them. Although the present application has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present application can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. An electrochemical device, comprising a housing, an electrode assembly, and a first conductive plate. The electrode assembly is disposed within the housing, and the first conductive plate is electrically connected to the electrode assembly and extends out of the housing. Wherein, the electrochemical device further includes a first layer. Defining the extending direction of the first conductive plate as the first direction, in the first direction, the first layer includes a connected first region and a second region. The first region is disposed within the housing, and the second region is disposed outside the housing. Defining the direction perpendicular to one surface of the first conductive plate as the second direction, when observing along the second direction, the second region partially overlaps with the first conductive plate. The first layer includes an insulating material; the second region includes a first protrusion and a second protrusion. When observing along the second direction, the first protrusion partially overlaps with the first conductive plate and protrudes along the first direction, and the second protrusion partially overlaps with the first conductive plate and protrudes along the first direction. Defining that the third direction, the first direction, and the second direction are perpendicular to each other. In the third direction, the first protrusion is separated from the second protrusion.

2. The electrochemical device according to claim 1, wherein, When observing along the second direction, the second region further includes a third protrusion disposed between the first protrusion and the second protrusion. The third protrusion protrudes along the first direction.

3. The electrochemical device according to claim 2, wherein, When observing along the second direction, the housing includes a first edge disposed between the first region and the second region. In the first direction, defining the distance from the first edge to the vertex of the first protrusion as the first distance, and the distance from the first edge to the vertex of the third protrusion as the second distance. The first distance is greater than the second distance.

4. The electrochemical device according to claim 2, wherein, The number of the third protrusions is multiple.

5. The electrochemical device according to claim 1, wherein, When observing along the second direction, defining the overlapping part of the second region and the first conductive plate as the overlapping area. The overlapping area includes a fourth protrusion that protrudes along the second direction.

6. The electrochemical device according to claim 3, wherein, The first layer includes a second edge that extends along the third direction. In the third direction, the first protrusion is disposed between the second edge and the second protrusion; In the first direction, the distance from the first edge to the second edge is the third distance. The first distance is greater than the third distance.

7. The electrochemical device according to claim 6, wherein, The second distance is greater than the third distance.

8. The electrochemical device according to claim 6, wherein, The third distance is from 0.2 mm to 3.5 mm, and the ratio range of the first distance to the third distance is from 1.09 to 16.

9. The electrochemical device according to claim 1, wherein, When observing along the second direction, the first conductive plate includes a first side surface and a second side surface that are oppositely arranged. In the first direction, the vertex of the first protrusion overlaps with the first side surface, and the vertex of the second protrusion overlaps with the second side surface.

10. The electrochemical device according to claim 1, wherein, The housing includes a main body portion and a connecting portion connecting the main body portion. The connecting portion is used to seal the main body portion. The electrode assembly is disposed in the main body portion. The first conductive plate is electrically connected to the electrode assembly and extends out of the connecting portion. The first region connects the first conductive plate and the connecting portion.

11. The electrochemical device according to claim 10, wherein, The housing includes a first housing and a second housing which are oppositely arranged. The first housing includes a first polymer layer, and the second housing includes a second polymer layer. The first polymer layer and the second polymer layer are adhesively bonded to each other to form the connecting portion.

12. The electrochemical device according to claim 11, wherein, The first polymer layer includes a first polymer material, and the second polymer layer includes a second polymer material. The first polymer material and the second polymer material are each independently selected from at least one of polypropylene, propylene copolymer, polyethylene, or polymethyl methacrylate.

13. The electrochemical device according to claim 10, wherein, The first layer further includes a third region. In the first direction, the first region is connected between the second region and the third region, and the third region is disposed within the main body portion. The third region includes a fifth convex portion and a sixth convex portion. When observed in the second direction, the fifth convex portion partially overlaps with the first conductive plate and protrudes away from the first direction, and the sixth convex portion partially overlaps with the first conductive plate and protrudes away from the first direction. In the third direction, the fifth convex portion and the sixth convex portion are separated from each other.

14. The electrochemical device according to claim 1, wherein, The insulating material is selected from at least one of polypropylene, polyethylene, polyethylene terephthalate, poly(ethylene naphthalate), polypropylene modified material, or polyethylene modified material.

15. An electronic device, which includes the electrochemical device according to any one of claims 1 to 14.

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