Electrochemical apparatus and electrical device

Abstract

An electrochemical apparatus (100) and an electrical device. The electrochemical apparatus (100) comprises an electrode assembly (20) and a casing. The casing comprises a first bottom wall (103) and a second bottom wall (104) which are arranged opposite to each other in a first direction (X), a first side wall (101) and a second side wall (102) which are arranged opposite to each other in a second direction (Y), and a third side wall (105) and a fourth side wall (106) which are arranged opposite to each other in a third direction (Z), the first direction (X) being the thickness direction of the electrode assembly (20). The first side wall (101), the second side wall (102), the third side wall (105), the fourth side wall (106), the first bottom wall (103) and the second bottom wall (104) define an accommodating space (1001), the electrode assembly (20) being accommodated in the accommodating space (1001). The first side wall (101) comprises a first base part (1011) and a first protruding part (1012); the first protruding part (1012) is connected to the first base part (1011) and the third side wall (105); the outer surface (10121) of the first protruding part (1012) protrudes in the second direction from the outer surface (10111) of the first base part (1011); the inner surface (10122) of the first protruding part (1012) is recessed relative to the inner surface (10112) of the first base part (1011) in a direction away from the electrode assembly (20). The electrochemical apparatus (100) reduces the risk of the electrode assembly (20) pressing corner parts of the casing, such that the usage reliability of the electrochemical apparatus is improved.

Description

Electrochemical devices and electrical equipment

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 202311641263.6, entitled “Electrochemical Device and Electrical Equipment,” filed on November 30, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to the field of battery technology, and in particular to an electrochemical device and electrical equipment. Background Art

[0004] Electrochemical devices are widely used in portable electronic devices, electric vehicles, power tools, drones, energy storage devices, and other fields. With the increasing energy density of electrochemical devices and the diversification of their application environments, higher requirements are placed on the reliability of electrochemical devices during use.

[0005] Summary of the Invention

[0006] In view of the above problems, the present application provides an electrochemical device and an electrical equipment, which can improve the reliability of the electrochemical device.

[0007] In a first aspect, the present application provides an electrochemical device, which includes an electrode assembly and a shell. The shell includes a first bottom wall and a second bottom wall arranged opposite to each other along a first direction, a first side wall and a second side wall arranged opposite to each other along a second direction, and a third side wall and a fourth side wall arranged opposite to each other along a third direction. The first direction is the thickness direction of the electrode assembly, and the first direction, the second direction, and the third direction are perpendicular to each other. The first side wall, the second side wall, the third side wall, the fourth side wall, the first bottom wall, and the second bottom wall are arranged to form a storage space, and the electrode assembly is accommodated in the storage space. The first side wall includes a first base and a first protrusion, the first protrusion connects the first base and the third side wall, the outer surface of the first protrusion protrudes from the outer surface of the first base along the second direction, and the inner surface of the first protrusion is recessed relative to the inner surface of the first base in a direction away from the electrode assembly.

[0008] The electrochemical device of the present application provides a first protrusion on the first side wall. When the electrode assembly expands, its corner is less likely to hit the first side wall. At the same time, due to the height difference between the first protrusion and the first base, when the shell expands along the first direction, the first bottom wall and / or the second bottom wall pulls the first side wall to cause the first side wall to collapse and deform. In this process, the electrode assembly will first contact the first base to form support, thereby alleviating the squeezing of the electrode assembly on the corner of the shell, thereby reducing the risk of damage to the corner of the shell and improving the reliability of the electrochemical device during use.

[0009] In any one or more of the above optional embodiments, the first sidewall further includes a second protrusion, the second protrusion connecting the first base and the fourth sidewall, the outer surface of the second protrusion protruding from the outer surface of the first base along the second direction, and the inner surface of the second protrusion being recessed relative to the inner surface of the first base, in a direction away from the electrode assembly. Thus, the first sidewall including the first and second protrusions can reduce the risk of damage at the corners on both sides of the housing, thereby improving the reliability of the electrochemical device.

[0010] In any one or more optional embodiments above, along the second direction, the distance between the outer surface of the first base and the outer surface of the second side wall is L, and the height of the first protrusion protruding from the outer surface of the first base is l1, satisfying: 0.005L≤l1≤0.1L.

[0011] In any one or more optional embodiments above, along the third direction, a distance between an outer surface of the third side wall and an outer surface of the fourth side wall is W, a width of the first protrusion is w1, and 0.05W≤w1≤0.3W is satisfied.

[0012] In any one or more optional embodiments above, along the second direction, the distance between the outer surface of the first base and the outer surface of the second side wall is L, and the height of the second protrusion protruding from the outer surface of the first base is l2, satisfying: 0.005L≤l2≤0.1L.

[0013] In any one or more optional embodiments above, along the third direction, the distance between the outer surface of the third side wall and the outer surface of the fourth side wall is W, the width of the second protrusion is w2, and 0.05W≤w2≤0.3W is satisfied.

[0014] In the above scheme, while improving the reliability of the electrochemical device, the electrochemical device can also have a higher volume energy density.

[0015] In any one or more optional embodiments above, the third sidewall includes a third base and a third protrusion, the third protrusion connects the third base and the first protrusion, the outer surface of the third protrusion protrudes from the outer surface of the third base along the third direction, and the inner surface of the third protrusion is recessed relative to the inner surface of the third base in a direction away from the electrode assembly. In this way, by providing the third protrusion on the third sidewall, when the electrode assembly expands, its corner is less likely to hit the third sidewall. At the same time, due to the height difference between the third protrusion and the third base, the shell expands along the first direction so that the first bottom wall and / or the second bottom wall pulls the third sidewall. During the process of collapse and deformation of the third sidewall, the electrode assembly will first contact the third base to form support, thereby further alleviating the squeezing of the electrode assembly on the corner of the shell, reducing the risk of damage to the corner of the shell, and further improving the reliability of the electrochemical device.

[0016] In any one or more optional embodiments above, the fourth sidewall includes a fourth base and a fourth protrusion, the fourth protrusion connects the fourth base and the second protrusion, the outer surface of the fourth protrusion protrudes from the outer surface of the fourth base along the third direction, and the inner surface of the fourth protrusion is recessed relative to the inner surface of the fourth base in a direction away from the electrode assembly. In this way, by providing the fourth protrusion on the fourth sidewall, when the electrode assembly expands, its corner is less likely to hit the fourth sidewall. At the same time, due to the height difference between the fourth protrusion and the fourth base, the shell expands along the first direction so that the first bottom wall and / or the second bottom wall pulls the fourth sidewall. During the process of collapse and deformation of the fourth sidewall, the electrode assembly will first contact the fourth base to form a support, thereby further alleviating the squeezing of the electrode assembly on the corner of the shell, reducing the risk of damage to the corner of the shell, and further improving the reliability of the electrochemical device.

[0017] In any one or more optional embodiments above, along the third direction, the distance between the outer surface of the third base and the outer surface of the fourth side wall is W, and the height of the third protrusion protruding from the outer surface of the third base is w3, satisfying: 0.05W≤w3≤0.3W.

[0018] In any one or more optional embodiments above, along the second direction, the distance between the outer surface of the first base and the outer surface of the second side wall is L, and the width of the third protrusion is l3, satisfying: 0.005L≤l3≤0.1L.

[0019] In any one or more optional embodiments above, along the third direction, the distance between the outer surface of the fourth base and the outer surface of the third side wall is W, and the height of the fourth protrusion protruding from the outer surface of the fourth base is w4, satisfying: 0.05W≤w4≤0.3W.

[0020] In any one or more optional embodiments above, along the second direction, the distance between the outer surface of the first base and the outer surface of the second side wall is L, and the width of the fourth protrusion is l4, satisfying: 0.005L≤l4≤0.1L.

[0021] In the above scheme, while further improving the reliability of the electrochemical device, the electrochemical device can also have a higher volume energy density.

[0022] In any one or more of the above optional embodiments, the first bottom wall includes a first main body and a fifth protrusion, the fifth protrusion is located in a corner region of the first bottom wall, the fifth protrusion connects the first protrusion and the third protrusion, the outer surface of the fifth protrusion protrudes from the outer surface of the first main body along the first direction, and the inner surface of the fifth protrusion is recessed relative to the inner surface of the first main body in a direction away from the electrode assembly. In this way, due to the height difference between the fifth protrusion and the first main body, when the shell expands along the first direction, the pulling on the corner can be alleviated, thereby further alleviating the compression of the electrode assembly on the shell corner, reducing the risk of damage to the shell corner, and further improving the reliability of the electrochemical device.

[0023] In any one or more of the above optional embodiments, the first bottom wall includes a first main body and a sixth protrusion, the sixth protrusion is located in a corner region of the first bottom wall, the sixth protrusion connects the second protrusion and the fourth protrusion, the outer surface of the sixth protrusion protrudes from the outer surface of the first main body along the first direction, and the inner surface of the sixth protrusion is recessed relative to the inner surface of the first main body in a direction away from the electrode assembly. In this way, due to the height difference between the sixth protrusion and the first main body, when the shell expands along the first direction, the pulling on the corner can be alleviated, thereby further alleviating the extrusion of the electrode assembly on the shell corner, reducing the risk of damage to the shell corner, and further improving the reliability of the electrochemical device.

[0024] In any one or more optional embodiments above, the distance between the outer surface of the first main body and the outer surface of the second bottom wall is T, the height of the fifth protrusion protruding from the outer surface of the first main body is t1, and the following conditions are satisfied: 0.05T≤t1≤0.4T.

[0025] In any one or more optional embodiments above, the distance between the outer surface of the first main body and the outer surface of the second bottom wall is T, the height of the sixth protrusion protruding from the outer surface of the first main body is t2, and the following conditions are satisfied: 0.05T≤t2≤0.4T.

[0026] In the above scheme, while further improving the reliability of the electrochemical device, the electrochemical device can also have a higher volume energy density.

[0027] In any one or more of the above optional embodiments, the electrode assembly has a wound structure, and the winding axis of the wound structure is oriented in the same direction as the second direction. In an electrode assembly with a wound structure, the presence of a cut surface of the current collector on the wound end face can more easily lead to damage at the corner of the housing during compression of the first sidewall. Therefore, setting the winding axis of the wound structure in the same direction as the second direction and the presence of the first protrusion, etc., can further improve the reliability of the electrochemical device during use.

[0028] In a second aspect, the present application provides an electrical device comprising any one or more of the electrochemical devices provided in the first aspect. Because the electrochemical device provided in the first aspect has a low risk of damage to the corners of the housing during use, the electrical device comprising the electrochemical device has a high reliability during use. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can also be obtained based on these drawings.

[0030] FIG1 is an axonometric view of an electrochemical device according to some embodiments of the present application;

[0031] FIG2 is a cross-sectional view of an electrochemical device according to some embodiments of the present application;

[0032] FIG3 is a cross-sectional view of an electrochemical device according to another embodiment of the present application;

[0033] FIG4 is an axonometric view of an electrochemical device according to some other embodiments of the present application;

[0034] FIG5 is a cross-sectional view of the section AA in FIG4 of the present application;

[0035] FIG6 is a cross-sectional view at BB in FIG4 of the present application;

[0036] FIG7 is a cross-sectional view taken along line CC in FIG4 of the present application.

[0037] The reference numerals are as follows: 100-electrochemical device; 1001-accommodation space; 101-first side wall; 1011-first base; 10111-outer surface of the first base; 10112-inner surface of the first base; 1012-first protrusion; 10121-outer surface of the first protrusion; 10122-inner surface of the first protrusion; 1013-second protrusion; 10131-outer surface of the second protrusion; 10132-inner surface of the second protrusion; 102-second side wall; 1021-outer surface of the second side wall; 103-first bottom wall; 1031-first main body; 10311-outer surface of the first main body; 10312-inner surface of the first main body; 1032-fifth protrusion; 10321-outer surface of the fifth protrusion; 10322-inner surface of the fifth protrusion; 1033-sixth protrusion; 10331-second The outer surface of the sixth protrusion; 10332-the inner surface of the sixth protrusion; 104-the second bottom wall; 1041-the outer surface of the second bottom wall; 105-the third side wall; 1051-the third base; 10511-the outer surface of the third base; 10512-the inner surface of the third base; 1052-the third protrusion; 10521-the outer surface of the third protrusion; 10522-the inner surface of the third protrusion; 106-the fourth side wall; 1061-the fourth base; 10611-the outer surface of the fourth base; 10612-the inner surface of the fourth base; 1062-the fourth protrusion; 10621-the outer surface of the fourth protrusion; 10622-the inner surface of the fourth protrusion; 20-the electrode assembly; 201-the pole ear; 202-the pole piece assembly; 200-the first reference surface; 300-the second reference surface; X-the first direction; Y-the second direction; Z-the third direction. DETAILED DESCRIPTION

[0038] The technical solution of the present application will be described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the following embodiments are only used to more clearly illustrate the technical solution of the present application, and are not intended to limit the scope of protection of the present application.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the description and claims of this application are intended to cover non-exclusive inclusions.

[0040] In the description of this application, the terms "first," "second," etc. are used solely to distinguish between different objects and should not be understood to indicate or imply relative importance or to implicitly indicate the quantity, specific order, or primary and secondary relationship of the technical features indicated. In the description of this application, "plurality" means more than two, unless otherwise specifically defined.

[0041] Those skilled in the art will appreciate that, without conflict, features of the embodiments described herein may be combined with other embodiments.

[0042] In the description of this application, the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of this application.

[0043] In the description of this application, unless otherwise specified or limited, the terms "installed," "connected," "connected," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; they can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of this application can be understood according to specific circumstances.

[0044] At present, electrochemical devices are widely used in portable electronic devices, electric vehicles, electric tools, drones, energy storage devices, VR / AR devices and other fields. In order to meet the demand for long-term battery life of electrical equipment, the energy density of electrochemical devices is required to be higher and higher. In order to further improve the energy density, measures such as increasing the coating weight of the active material on the current collector per unit area or using active materials with high specific capacity (for example, for lithium-ion batteries, the negative electrode uses silicon-based materials) are usually adopted. However, the inventors of this application have found that for such electrochemical devices, during the charge and discharge cycle, the expansion of the electrode sheet will increase significantly, causing the electrode assembly to squeeze the corners of the shell, increasing the risk of damage at the corners of the shell. At the same time, when the shell expands, the corners of the shell are subjected to inward pulling force. Under the squeezing of the electrode assembly, the risk of damage at the corners of the shell is further increased, thereby affecting the reliability of the electrochemical device.

[0045] In view of this, please refer to Figures 1 and 2. In a first aspect, the present application provides an electrochemical device 100, which includes an electrode assembly 20 and a shell. The shell includes a first bottom wall 103 and a second bottom wall 104 arranged opposite to each other along a first direction X, a first side wall 101 and a second side wall 102 arranged opposite to each other along a second direction Y, and a third side wall 105 and a fourth side wall 106 arranged opposite to each other along a third direction Z. The first direction X is the thickness direction of the electrode assembly 20, and the first direction X, the second direction Y and the third direction Z are perpendicular to each other; the first side wall 101, the second side wall 102, the third side wall 105, the fourth side wall 106, the first bottom wall 103 and the second bottom wall 104 are arranged to form a receiving space 1001, and the electrode assembly 20 is accommodated in the receiving space 1001. In which, the first side wall 101 includes a first base 1011 and a first protrusion 1012, the first protrusion 1012 connects the first base 1011 and the third side wall 105, the outer surface 10121 of the first protrusion protrudes from the outer surface 10111 of the first base along the second direction Y, and the inner surface 10122 of the first protrusion is recessed relative to the inner surface 10112 of the first base in a direction away from the electrode assembly 20. The electrochemical device 100 of the present application is provided with a first protrusion 1012 on the first side wall 101. When the electrode assembly 20 expands, its corner is less likely to hit the first side wall 101. At the same time, due to the height difference between the first protrusion 1012 and the first base 1011, when the shell expands along the first direction X, the first bottom wall 103 and / or the second bottom wall 104 pulls the first side wall 101 to cause the first side wall 101 to collapse and deform. In this process, the electrode assembly 20 will first contact the first base 1011 to form a support, thereby alleviating the squeezing of the electrode assembly 20 on the corners of the shell, thereby reducing the risk of damage to the corners of the shell and improving the reliability of the electrochemical device during use.

[0046] In some embodiments, the electrode assembly 20 includes a tab 201 and a plate assembly 202. The plate assembly 202 is accommodated in the housing space 1001 of the housing. One end of the tab 201 is electrically connected to the plate assembly 202, and the other end of the tab 201 extends out of the housing. The plate assembly 202 generally includes a positive electrode sheet, a separator, and a negative electrode sheet, with the separator being disposed between the positive and negative electrode sheets. In some embodiments, the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer, the positive electrode active material layer being coated on the surface of the positive electrode current collector. The tab 201 includes a positive tab, which is connected to the positive electrode current collector. The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer, the negative electrode active material layer being coated on the surface of the negative electrode current collector. The tab 201 includes a negative tab, which is connected to the negative electrode current collector. Taking lithium-ion batteries as an example, the positive electrode current collector can be aluminum foil, and the positive electrode active material can include at least one of lithium cobalt oxide, lithium iron phosphate, lithium manganese iron phosphate, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, or lithium manganese oxide; the negative electrode current collector can be copper foil, and the negative electrode active material can include at least one of carbon materials or silicon-based materials. In some embodiments, the tab 201 can be integrally formed with the current collector. In other embodiments, the tab 201 can be separately processed and formed from the pole piece, and the tab 201 is electrically connected to the current collector of the pole piece by riveting or welding. In some embodiments, the structure of the electrode assembly 20 can include, but is not limited to, a wound type or a laminated type.

[0047] Hereinafter, the outer side refers to the side away from the accommodation space 1001 , and the inner side refers to the side facing the accommodation space 1001 .

[0048] The material of the shell can be aluminum-plastic film, steel shell, aluminum shell, etc., and this application does not impose specific restrictions. The shell generally includes a plurality of wall portions, and the plurality of wall portions together define a storage space 1001. In some embodiments, the shell may include a first part and a second part, and the first part and the second part are packaged together to form a storage space 1001. One of the first part and the second part may have an opening, or both may have an opening. The structure of the first part may be the same as or different from the structure of the second part. For example, a groove may be provided in the first part, and the notch of the groove is an opening, and the electrode assembly 20 may be assembled into the groove through the notch. The second part may be in the shape of a flat plate, and the second part closes the notch to form a closed storage space 1001. For example, grooves may also be provided in both the first part and the second part. After the two grooves are relative to each other and the first part and the second part are packaged, the two grooves together define a closed storage space 1001.

[0049] In some embodiments, referring to Figures 1 and 2, a first recess for accommodating the electrode assembly 20 may be provided in the first portion of the housing. The first recess includes a first bottom wall 103 in the first direction X, and includes opposing first and second side walls 101 and 102 in the second direction Y. The first recess includes opposing third and fourth side walls 105 and 106 in the third direction Z. The second portion of the housing encloses the first recess to form an accommodating space 1001. The second portion includes a second bottom wall 104 opposing the first bottom wall 103 in the first direction X. The first protrusion 1012 may be formed simultaneously with the first recess. This design improves processing efficiency and reduces costs. In other embodiments, the second portion may include a second recess corresponding to the first recess.

[0050] The first sidewall 101 includes a first base 1011 and a first protrusion 1012. The first protrusion 1012 connects the first base 1011 and the third sidewall 105, meaning that the first protrusion 1012 is disposed at the corner formed by the third sidewall 105 and the first sidewall 101 of the housing. It can also be understood that the orthographic projection of the first protrusion 1012 on the first reference plane 200 is located at the first end of the orthographic projection of the first sidewall 101 on the first reference plane 200 along the third direction Z, where the first reference plane 200 is perpendicular to the second direction Y. The corners of the electrode assembly 20 correspond to the corners of the housing. A corner can generally be understood as the location where at least three walls of the housing defining the accommodating space 1001 intersect. The shape of the electrode assembly 20 can be understood as a reference body including multiple surfaces. Taking the electrode assembly 20 formed by lamination as an example, the electrode assembly 20 can include a top surface and a bottom surface arranged opposite to each other along the stacking direction of the electrode sheets, and a side surface arranged around the edge of the top surface and connected to the edge of the bottom surface. The angular position of the electrode assembly 20 can refer to the corner position of the projection of the electrode assembly 20 along the stacking direction of the electrode sheets. Taking the electrode assembly 20 formed by winding as an example, the electrode assembly 20 can include an outer peripheral surface and a top surface and a bottom surface opposite to each other along the winding axis. The top surface and the bottom surface are both connected to the edge of the outer peripheral surface. The angular position of the electrode assembly 20 can refer to the corner position of the projection of the electrode assembly 20 along its thickness direction. Among them, the projection of the first protrusion 1012 along the second direction Y on the first reference surface 200 at least partially overlaps with the projection of the angular position of the electrode assembly 20 on the first reference surface 200.

[0051] According to some embodiments of the present application, referring to FIG1 and FIG2 , the first sidewall 101 further includes a second protrusion 1013. The second protrusion 1013 connects the first base 1011 and the fourth sidewall 106. The outer surface 10131 of the second protrusion protrudes from the outer surface 10111 of the first base along the second direction Y, and the inner surface 10132 of the second protrusion is recessed relative to the inner surface 10112 of the first base, in a direction away from the electrode assembly 20. The second protrusion 1013 connects the first base 1011 and the fourth sidewall 106, meaning that the second protrusion 1013 is disposed at the corner formed by the fourth sidewall 106 and the first sidewall 101 of the housing. It can also be understood that the orthographic projection of the second protrusion 1013 on the first reference plane 200 is located at the second end of the first sidewall 101, which is opposite the first end, along the third direction Z. Thus, the first sidewall 101 includes the first protrusion 1012 and the second protrusion 1013, which can reduce the risk of damage at the corners of the housing and further improve the reliability of the electrochemical device 100. The size of the second protrusion 1013 can be the same as or different from the size of the first protrusion 1012.

[0052] According to some embodiments of the present application, referring to FIG1 and FIG2 , along the second direction Y, the distance between the outer surface 10111 of the first base and the outer surface 1021 of the second sidewall is L, and the height of the first protrusion 1012 protruding from the outer surface 10111 of the first base is l1, satisfying the following: 0.005L≤l1≤0.1L. The height l1 of the first protrusion 1012 protruding from the outer surface 10111 of the first base can be 0.005L, 0.006L, 0.007L, 0.008L, 0.009L, 0.01L, 0.015L, 0.02L, 0.04L, 0.05L, 0.06L, 0.08L, 0.1L, or a range consisting of any two of the foregoing.

[0053] According to some embodiments of the present application, with continued reference to FIG1 and FIG2 , along the third direction Z, a distance W is defined between an outer surface of the third sidewall 105 and an outer surface of the fourth sidewall 106, and a width w1 of the first protrusion 1012 satisfies the following conditions: 0.05W≤w1≤0.3W. The width w1 of the first protrusion 1012 may be 0.05W, 0.06W, 0.07W, 0.08W, 0.09W, 0.1W, 0.11W, 0.12W, 0.13W, 0.14W, 0.15W, 0.16W, 0.17W, 0.18W, 0.19W, 0.2W, 0.21W, 0.22W, 0.23W, 0.24W, 0.25W, 0.26W, 0.27W, 0.28W, 0.29W, 0.3W, or a range consisting of any two of the foregoing.

[0054] In the above solution, the first protrusion 1012 satisfies 0.005L≤l1≤0.1L in the second direction Y, and / or satisfies 0.05W≤w1≤0.3W in the third direction Z. This design improves the reliability of the electrochemical device 100 while also enabling the electrochemical device 100 to have a higher volumetric energy density.

[0055] According to some embodiments of the present application, referring to FIG1 and FIG2 , along the second direction Y, the distance between the outer surface 10111 of the first base and the outer surface 1021 of the second sidewall is L, and the height of the second protrusion 1013 protruding from the outer surface 10111 of the first base is l2, satisfying the following: 0.005L≤l2≤0.1L. The height l2 of the second protrusion 1013 protruding from the outer surface 10111 of the first base can be 0.005L, 0.006L, 0.007L, 0.008L, 0.009L, 0.01L, 0.015L, 0.02L, 0.04L, 0.05L, 0.06L, 0.08L, 0.1L, or a range consisting of any two of the foregoing.

[0056] According to some embodiments of the present application, referring to FIG1 and FIG2 , along the third direction Z, a distance W is defined between an outer surface of the third sidewall 105 and an outer surface of the fourth sidewall 106, and a width w2 of the second protrusion 1013 satisfies the following conditions: 0.05W≤w2≤0.3W. The width w2 of the second protrusion 1013 can be 0.05W, 0.06W, 0.07W, 0.08W, 0.09W, 0.1W, 0.11W, 0.12W, 0.13W, 0.14W, 0.15W, 0.16W, 0.17W, 0.18W, 0.19W, 0.2W, 0.21W, 0.22W, 0.23W, 0.24W, 0.25W, 0.26W, 0.27W, 0.28W, 0.29W, 0.3W, or a range consisting of any two of the foregoing.

[0057] In the above solution, the second protrusion 1013 satisfies 0.005L≤l2≤0.1L in the second direction Y, and / or satisfies 0.05W≤w2≤0.3W in the third direction Z. This design not only further improves the reliability of the electrochemical device 100 but also enables the electrochemical device 100 to have a higher volumetric energy density.

[0058] According to some embodiments of the present application, referring to FIG. 3 , the third sidewall 105 includes a third base portion 1051 and a third protrusion 1052. The third protrusion 1052 connects the third base portion 1051 and the first protrusion 1012. An outer surface 10521 of the third protrusion protrudes from the outer surface 10511 of the third base portion along a third direction Z. An inner surface 10522 of the third protrusion is recessed relative to the inner surface 10512 of the third base portion in a direction away from the electrode assembly 20. The third protrusion 1052 connects the third base portion 1051 and the first protrusion 1012, meaning that the third protrusion 1052 is also located at a corner of the housing. In this way, by providing the third protrusion 1052 on the third side wall 105, when the electrode assembly 20 expands, its corner is less likely to hit the third side wall 105. At the same time, due to the height difference between the third protrusion 1052 and the third base 1051, when the shell expands along the first direction X, the first bottom wall 103 and / or the second bottom wall 104 pulls the third side wall 105 to cause the third side wall 105 to collapse and deform. In this process, the electrode assembly 20 will first contact the third base 1051 to form support, thereby further alleviating the squeezing of the electrode assembly 20 on the corners of the shell, reducing the risk of damage to the corners of the shell, and further improving the reliability of the electrochemical device 100.

[0059] According to some embodiments of the present application, with continued reference to FIG. 3 , the fourth sidewall 106 includes a fourth base portion 1061 and a fourth protrusion 1062. The fourth protrusion 1062 connects the fourth base portion 1061 and the second protrusion 1013. An outer surface 10621 of the fourth protrusion protrudes from the outer surface 10611 of the fourth base portion along the third direction Z. An inner surface 10622 of the fourth protrusion is recessed relative to the inner surface 10612 of the fourth base portion in a direction away from the electrode assembly 20. The fourth protrusion 1062 connects the fourth base portion 1061 and the second protrusion 1013, meaning that the fourth protrusion 1062 is also located at a corner of the housing. In this way, by providing the fourth protrusion 1062 on the fourth side wall 106, when the electrode assembly 20 expands, its corner is less likely to hit the fourth side wall 106. At the same time, due to the height difference between the fourth protrusion 1062 and the fourth base 1061, when the shell expands along the first direction X, the first bottom wall 103 and / or the second bottom wall 104 pulls the fourth side wall 106 to cause the fourth side wall 106 to collapse and deform. In this process, the electrode assembly 20 will first contact the fourth base 1061 to form support, thereby further alleviating the squeezing of the electrode assembly 20 on the corners of the shell, reducing the risk of damage to the corners of the shell, and further improving the reliability of the electrochemical device 100.

[0060] According to some embodiments of the present application, please refer to Figure 3. Along the third direction Z, the distance between the outer surface 10511 of the third base and the outer surface of the fourth side wall 106 is W, and the height of the third protrusion 1052 protruding from the outer surface 10511 of the third base is w3, satisfying: 0.05W≤w3≤0.3W. The height w3 of the third protrusion 1052 protruding from the outer surface 10511 of the third base can be 0.05W, 0.06W, 0.07W, 0.08W, 0.09W, 0.1W, 0.11W, 0.12W, 0.13W, 0.14W, 0.15W, 0.16W, 0.17W, 0.18W, 0.19W, 0.2W, 0.21W, 0.22W, 0.23W, 0.24W, 0.25W, 0.26W, 0.27W, 0.28W, 0.29W, 0.3W or a range consisting of any two of the above.

[0061] According to some embodiments of the present application, referring to FIG. 3 , along the second direction Y, the distance between the outer surface 10111 of the first base portion and the outer surface 1021 of the second sidewall is L, and the width of the third protrusion 1052 is l3, satisfying the following: 0.005L≤l3≤0.1L. The width l3 of the third protrusion 1052 can be 0.005L, 0.006L, 0.007L, 0.008L, 0.009L, 0.01L, 0.015L, 0.02L, 0.04L, 0.05L, 0.06L, 0.08L, 0.1L, or a range consisting of any two of the foregoing.

[0062] According to some embodiments of the present application, please refer to Figure 3. Along the third direction Z, the distance between the outer surface 10611 of the fourth base and the outer surface of the third side wall 105 is W, and the height of the fourth protrusion 1062 protruding from the outer surface of the fourth base 1061 is w4, satisfying: 0.05W≤w4≤0.3W. The height w4 of the fourth protrusion 1062 protruding from the outer surface of the fourth base 1061 can be 0.05W, 0.06W, 0.07W, 0.08W, 0.09W, 0.1W, 0.11W, 0.12W, 0.13W, 0.14W, 0.15W, 0.16W, 0.17W, 0.18W, 0.19W, 0.2W, 0.21W, 0.22W, 0.23W, 0.24W, 0.25W, 0.26W, 0.27W, 0.28W, 0.29W, 0.3W or a range composed of any two of the above.

[0063] According to some embodiments of the present application, referring to FIG. 3 , along the second direction Y, the distance between the outer surface 10111 of the first base portion and the outer surface 1021 of the second sidewall is L, and the width of the fourth protrusion 1062 is l4, satisfying the following: 0.005L≤l4≤0.1L. The width l4 of the fourth protrusion 1062 can be 0.005L, 0.006L, 0.007L, 0.008L, 0.009L, 0.01L, 0.015L, 0.02L, 0.04L, 0.05L, 0.06L, 0.08L, 0.1L, or a range consisting of any two of the foregoing.

[0064] In the above solution, the third protrusion 1052 satisfies 0.05W≤w3≤0.3W in the third direction Z, and / or the third protrusion 1052 satisfies 0.005L≤l3≤0.1L in the second direction Y, and / or the fourth protrusion 1062 satisfies 0.05W≤w4≤0.3W in the third direction Z, and / or the fourth protrusion 1062 satisfies 0.005L≤l4≤0.1L in the second direction Y. This design not only further improves the reliability of the electrochemical device 100 but also enables the electrochemical device 100 to have a higher volumetric energy density.

[0065] According to some embodiments of the present application, referring to Figures 4, 6, and 7, the first bottom wall 103 includes a first main body 1031 and a fifth protrusion 1032. The fifth protrusion 1032 is located in a corner region of the first bottom wall 103. The fifth protrusion 1032 connects the first protrusion 1012 and the third protrusion 1052. The outer surface 10321 of the fifth protrusion protrudes from the outer surface 10311 of the first main body along the first direction X, and the inner surface 10322 of the fifth protrusion is recessed relative to the inner surface 10312 of the first main body, away from the electrode assembly 20. As such, due to the height difference between the fifth protrusion 1032 and the first main body 1031, when the housing expands in the first direction X, the pull on the corner is alleviated, thereby further alleviating the pressure of the electrode assembly 20 on the housing corner, reducing the risk of damage to the housing corner, and further improving the reliability of the electrochemical device 100. The fifth protrusion 1032 is located in a corner region of the first bottom wall 103. The corner region of the first bottom wall 103 can be understood as the region near the intersection of two sides of the orthographic projection of the first bottom wall 103 on the second reference plane 300. The second reference plane 300 is perpendicular to the first direction X. A corner can generally be understood as the location where at least three walls of the housing defining the accommodating space 1001 intersect. The orthographic projection of the fifth protrusion 1032 along the first direction X on the second reference plane 300 at least partially overlaps with the orthographic projection of the corner of the electrode assembly 20 on the second reference plane 300.

[0066] According to some embodiments of the present application, referring to FIG. 4 , FIG. 6 , and FIG. 7 , the first bottom wall 103 includes a first main body 1031 and a sixth protrusion 1033. The sixth protrusion 1033 is located at a corner region of the first bottom wall 103 . The sixth protrusion 1033 connects the second protrusion 1013 and the fourth protrusion 1062 . The outer surface 10331 of the sixth protrusion protrudes beyond the outer surface 10311 of the first main body along the first direction X. The inner surface 10332 of the sixth protrusion is recessed relative to the inner surface 10312 of the first main body, in a direction away from the electrode assembly 20 . Thus, due to the height difference between the sixth protrusion 1033 and the first main body 1031 , when the housing expands along the first direction X, the pull on the corner is alleviated, thereby further alleviating the pressure of the electrode assembly 20 on the housing corner, reducing the risk of damage to the housing corner, and further improving the reliability of the electrochemical device 100 . The orthographic projection of the sixth protrusion 1033 along the first direction X on the second reference plane 300 at least partially overlaps with the orthographic projection of the angular position of the electrode assembly 20 on the second reference plane 300 .

[0067] In some embodiments, the first bottom wall 103 includes a first main body portion 1031, a fifth protrusion 1032 and a sixth protrusion 1033. The fifth protrusion 1032 and the sixth protrusion 1033 are arranged relatively to each other along the third direction Z, or the fifth protrusion 1032 and the sixth protrusion 1033 can be said to be located at two adjacent corners of the first bottom wall 103 along the third direction Z.

[0068] According to some embodiments of the present application, referring to Figures 4-7 , the distance between the outer surface 10311 of the first main body and the outer surface 1041 of the second bottom wall is T, and the height t1 of the fifth protrusion 1032 protruding from the outer surface 10311 of the first main body satisfies the following conditions: 0.05T≤t1≤0.4T. The height t1 of the fifth protrusion 1032 protruding from the outer surface 10311 of the first main body can be 0.05T, 0.06T, 0.07T, 0.08T, 0.09T, 0.1T, 0.2T, 0.3T, 0.4T, or a range consisting of any two of the foregoing.

[0069] According to some embodiments of the present application, the height t2 of the sixth protrusion 1033 protruding from the outer surface 10311 of the first body portion satisfies the following conditions: 0.05T≤t2≤0.4T. The height t2 of the fifth protrusion 1032 protruding from the outer surface 10311 of the first body portion can be 0.05T, 0.06T, 0.07T, 0.08T, 0.09T, 0.1T, 0.2T, 0.3T, 0.4T, or a range consisting of any two of the above.

[0070] In the above solution, the fifth protrusion 1032 has a value of 0.05T≤t1≤0.4T in the first direction X, and / or the sixth protrusion 1033 has a value of 0.05T≤t2≤0.4T in the first direction X. This design further improves the reliability of the electrochemical device 100 while also enabling the electrochemical device 100 to have a higher volumetric energy density.

[0071] According to some embodiments of the present application, referring to Figures 1-7, the electrode assembly 20 has a wound structure, and the winding axis direction of the wound structure is the same as the second direction Y. Due to the presence of the cut surface of the current collector on the wound end surface of the wound electrode assembly 20, the process of squeezing the first sidewall 101 is more likely to cause damage at the corner of the housing. Therefore, setting the winding axis direction of the wound structure to be the same as the second direction Y and the presence of the first protrusion 1012 and the like can further improve the reliability of the electrochemical device 100 during use.

[0072] Depending on the assembly environment of the electrochemical device 100 in the electrical equipment, the shape of the electrochemical device 100 can be rectangular, square, triangular, trapezoidal, L-shaped, T-shaped, etc. The electrochemical device of the present application includes but is not limited to lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries.

[0073] The following takes lithium-ion batteries as an example to further explain the technical solution of the application.

[0074] Example 1

[0075] Preparation of positive electrode sheet: The positive electrode active material lithium cobalt oxide, the conductive agent Super P, and the binder polyvinylidene fluoride are mixed in a weight ratio of 97.5:1:1.5, N-methylpyrrolidone (NMP) is added, and the mixture is stirred evenly under the action of a vacuum mixer to obtain a positive electrode slurry; the positive electrode slurry is evenly coated on the positive electrode current collector aluminum foil; and the mixture is dried, and then cold pressed, cut into pieces, and slit to obtain a positive electrode sheet.

[0076] Preparation of the negative electrode sheet: The negative electrode active material artificial graphite, the thickener sodium carboxymethyl cellulose (CMC), and the binder styrene-butadiene rubber (SBR) are mixed in a weight ratio of 96:1.5:2.5, deionized water is added, and the mixture is stirred evenly under the action of a vacuum mixer to obtain a negative electrode slurry; the negative electrode slurry is evenly coated on the negative electrode current collector copper foil; and the mixture is dried, and then cold pressed, cut, and slit to obtain a negative electrode sheet.

[0077] Preparation of electrolyte: In a dry argon atmosphere glove box, ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) were mixed in a mass ratio of 3:5:2, and lithium salt LiPF6 was added. After mixing evenly, an electrolyte was obtained, wherein the mass concentration of LiPF6 was 12.5%.

[0078] Preparation of the isolation membrane: Alumina and polyvinylidene fluoride are mixed evenly in deionized water in a weight ratio of 95:5 to form a ceramic coating slurry, and polyvinylidene fluoride is dispersed in deionized water and mixed evenly to form a bonding coating slurry; the ceramic coating slurry is then evenly coated on one surface of the polyethylene porous substrate by a micro-concave coating method, and after drying, the bonding coating slurry is sprayed on the ceramic coating surface and the other side surface of the polyethylene porous substrate, and the desired isolation membrane is obtained after drying.

[0079] Preparation of lithium-ion batteries: stack the positive electrode sheet, isolation membrane, and negative electrode sheet in sequence, so that the isolation membrane is placed between the positive and negative electrode sheets to play an isolating role, and obtain a wound electrode assembly after winding; after welding the pole ear 201, place the electrode assembly 20 in an outer packaging aluminum-plastic film with a single-sided pit, wherein, while the pit is being punched, a first convex portion 1012 and a second convex portion 1013 are formed at the two ends of the first side wall 101, and the pole ear 201 is led out from the side of the first side wall 101. After preliminary packaging, the above-prepared electrolyte is injected, and after vacuum packaging, standing, formation, shaping, capacity testing and other processes, a lithium-ion battery is obtained. Among them, the length L of the lithium-ion battery is 87 mm, the width W is 64 mm, and the thickness T is 4.8 mm. The height l1 of the first protrusion 1012 protruding from the outer surface 10111 of the first base and the height l2 of the second protrusion 1013 protruding from the outer surface 10111 of the first base are 0.005L, and the width w1 of the first protrusion 1012 and the width w2 of the second protrusion 1013 are 0.1W.

[0080] Example 2-8: The only difference from Example 1 is that the height l1 of the first protrusion 1012 protruding from the outer surface 10111 of the first base and the height l2 of the second protrusion 1013 protruding from the outer surface 10111 of the first base are adjusted according to the proportions in Table 1.

[0081] Embodiments 9-11: The only difference from Embodiment 2 is that the width w1 of the first convex portion 1012 and the width w2 of the second convex portion 1013 are adjusted according to the ratio in Table 1.

[0082] Comparative Example 1: The difference from Example 1 is that the first convex portion 1012 and the second convex portion 1013 are not provided.

[0083] Cyclic damage test: 10 lithium-ion batteries were tested in each group at a test temperature of 35°C. The lithium-ion batteries were placed in a constant temperature environment at 35°C and allowed to stand for 60 minutes to allow the lithium-ion batteries to reach a constant temperature state. They were then charged at a constant current of 1C to 4.48V, and then charged at a constant voltage of 4.48V to a current of 0.05C and allowed to stand for 5 minutes. Next, they were discharged at a constant current of 0.7C to 3V and allowed to stand for 5 minutes. This constituted one charge and discharge cycle. The above charge and discharge cycles were repeated 500 times. After the cycles were completed, the lithium-ion batteries were inspected for damage or leakage at the corners, and the number of lithium-ion batteries with damage or leakage was counted.

[0084] The specific parameters and cycle damage test results of the lithium-ion batteries of various embodiments and comparative examples are shown in Table 1.

[0085] Table 1: Specific parameters and cycle damage test results of lithium-ion batteries of Examples and Comparative Examples

[0086] As shown in Table 1, the lithium-ion batteries of Examples 1-11 can effectively reduce the probability of damage during the cycle of the lithium-ion batteries. Therefore, it can be seen that the provision of the first protrusion 1012 and the second protrusion 1013 can improve the reliability of the electrochemical device 100 during use.

[0087] The second aspect of the present application further provides an electrical device comprising the electrochemical device 100 provided in one or more of the above embodiments. In the above technical solution, since the electrochemical device 100 provided in the first embodiment has a low risk of damage to the corners of the housing during use, the electrical device comprising the electrochemical device 100 has a high reliability during use. The electrical devices of the present application include, but are not limited to: portable electronic devices, electric vehicles, electric tools, drones, energy storage devices, VR / AR devices, etc.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not deviate from the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of this application, and they should all be included in the scope of the claims and description of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way.

Claims

1. An electrochemical device, wherein: include: Electrode assembly; The shell comprises a first bottom wall and a second bottom wall arranged opposite to each other along a first direction, a first side wall and a second side wall arranged opposite to each other along a second direction, and a third side wall and a fourth side wall arranged opposite to each other along a third direction, wherein the first direction is a thickness direction of the electrode assembly, and the first direction, the second direction and the third direction are perpendicular to each other; The first side wall, the second side wall, the third side wall, the fourth side wall, the first bottom wall and the second bottom wall are arranged to form a receiving space, and the electrode assembly is received in the receiving space; Wherein, the first side wall includes a first base and a first convex portion, the first convex portion connects the first base and the third side wall, the outer surface of the first convex portion protrudes from the outer surface of the first base along the second direction, and the inner surface of the first convex portion is recessed relative to the inner surface of the first base toward a direction away from the electrode assembly.

2. The electrochemical device according to claim 1, wherein: The first side wall also includes a second protrusion, which connects the first base and the fourth side wall, the outer surface of the second protrusion protrudes from the outer surface of the first base along the second direction, and the inner surface of the second protrusion is recessed relative to the inner surface of the first base in a direction away from the electrode assembly.

3. The electrochemical device according to claim 1 or 2, wherein: The electrochemical device satisfies at least one of the following conditions: (1) Along the second direction, the distance between the outer surface of the first base and the outer surface of the second side wall is L, and the height of the first protrusion protruding from the outer surface of the first base is l1, satisfying: 0.005L≤l1≤0.1L; (2) Along the third direction, a distance between an outer surface of the third side wall and an outer surface of the fourth side wall is W, a width of the first protrusion is w1, and the following conditions are satisfied: 0.05W≤w1≤0.3W.

4. The electrochemical device according to claim 2, wherein: The electrochemical device satisfies at least one of the following conditions: (1) Along the second direction, the distance between the outer surface of the first base and the outer surface of the second side wall is L, and the height of the second protrusion protruding from the outer surface of the first base is l2, satisfying: 0.005L≤l2≤0.1L; (2) Along the third direction, a distance between an outer surface of the third side wall and an outer surface of the fourth side wall is W, and a width of the second protrusion is w2, satisfying: 0.05W≤w2≤0.3W.

5. The electrochemical device according to claim 2 or 4, wherein: The electrochemical device satisfies at least one of the following conditions: (1) the third side wall comprises a third base and a third protrusion, the third protrusion connects the third base and the first protrusion, an outer surface of the third protrusion protrudes from an outer surface of the third base along the third direction, and an inner surface of the third protrusion is recessed relative to an inner surface of the third base in a direction away from the electrode assembly; (2) The fourth side wall includes a fourth base and a fourth protrusion, the fourth protrusion connects the fourth base and the second protrusion, the outer surface of the fourth protrusion protrudes from the outer surface of the fourth base along the third direction, and the inner surface of the fourth protrusion is recessed relative to the inner surface of the fourth base in a direction away from the electrode assembly.

6. The electrochemical device according to claim 5, wherein: The electrochemical device satisfies at least one of the following conditions: (1) Along the third direction, the distance between the outer surface of the third base portion and the outer surface of the fourth side wall is W, and the height of the third protrusion protruding from the outer surface of the third base portion is w3, satisfying: 0.05W≤w3≤0.3W; (2) Along the second direction, the distance between the outer surface of the first base and the outer surface of the second side wall is L, and the width of the third protrusion is l3, satisfying: 0.005L≤l3≤0.1L; (3) Along the third direction, the distance between the outer surface of the fourth base portion and the outer surface of the third side wall is W, and the height of the fourth protrusion protruding from the outer surface of the fourth base portion is w4, satisfying: 0.05W≤w4≤0.3W; (4) Along the second direction, the distance between the outer surface of the first base and the outer surface of the second side wall is L, and the width of the fourth protrusion is l4, satisfying: 0.005L≤l4≤0.1L.

7. The electrochemical device according to claim 5 or 6, wherein: The electrochemical device satisfies at least one of the following conditions: (1) The first bottom wall includes a first main body and a fifth protrusion, wherein the fifth protrusion is located in a corner area of ​​the first bottom wall, the fifth protrusion connects the first protrusion and the third protrusion, an outer surface of the fifth protrusion protrudes from an outer surface of the first main body along the first direction, and an inner surface of the fifth protrusion is recessed relative to an inner surface of the first main body in a direction away from the electrode assembly; (2) The first bottom wall includes a first main body and a sixth protrusion, wherein the sixth protrusion is located in a corner area of ​​the first bottom wall, the sixth protrusion connects the second protrusion and the fourth protrusion, the outer surface of the sixth protrusion protrudes from the outer surface of the first main body along the first direction, and the inner surface of the sixth protrusion is recessed relative to the inner surface of the first main body in a direction away from the electrode assembly.

8. The electrochemical device according to claim 7, wherein: The distance between the outer surface of the first main body and the outer surface of the second bottom wall is T, and the electrochemical device satisfies at least one of the following conditions: (1) The height of the fifth protrusion protruding from the outer surface of the first main body is t1, which satisfies: 0.05T≤t1≤0.4T; (2) The height of the sixth protrusion protruding from the outer surface of the first main body is t2, which satisfies: 0.05T≤t2≤0.4T.

9. The electrochemical device according to any one of claims 1 to 8, wherein: The electrode assembly is a winding structure, and the winding axis direction of the winding structure is the same as the second direction.

10. An electrical device, wherein: Comprising the electrochemical device according to any one of claims 1-9.

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