Electrochemical device and electronic device

Abstract

An electrochemical device includes a housing and an electrode assembly. The housing has a receiving cavity and a first wall covering the receiving cavity, the first wall including a first opening. The electrochemical device also includes a plate-like member and a cover. The plate-like member is disposed between the first wall and the electrode assembly. The plate-like member includes a second opening. Viewed from a first direction, the cover covers the first opening and the second opening. The cover includes a cover portion and a protrusion extending toward the electrode assembly. In the first direction, the protrusion extends into the receiving cavity and abuts against a second edge of the second opening. In a second direction, the plate-like member includes a first portion and a second portion connected to the first portion and extending offset from the second direction, the second portion surrounding the protrusion to form a second edge. In the first direction, the distance between the first portion and the cover portion is a first distance, and the distance between the second edge and the cover portion is a second distance, the first distance and the second distance being different. An electronic device is also provided. This application can improve the reliability and safety of electrochemical devices.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, and more particularly to an electrochemical device and an electronic device having said electrochemical device. Background Technology

[0002] Electrochemical devices (such as secondary batteries) are widely used in electronic mobile devices, power tools and electric vehicles, and people have increasingly higher requirements for the reliability and safety of electrochemical devices.

[0003] Because electrochemical devices require a relatively sealed environment to function properly, their casings need to have a certain sealing capability. In some cases, gases may be generated inside the casing during operation. If these gases accumulate and are not properly released into the external environment, the internal pressure can continuously increase, thus affecting the reliability and safety of the electrochemical device. Summary of the Invention

[0004] This application provides an electrochemical device with high reliability and safety.

[0005] Additionally, this application also provides an electronic device having the above-described electrochemical device.

[0006] This application provides an electrochemical device, including a housing and an electrode assembly. The housing has a receiving cavity and a first wall covering the receiving cavity, the first wall including a first opening. The electrode assembly is received within the receiving cavity. The electrochemical device also includes a plate-like member and a cover. The plate-like member is received within the receiving cavity and disposed between the first wall and the electrode assembly. The plate-like member includes a second opening. A first direction is defined as the orientation in which the plate-like member and the electrode assembly are arranged. Viewed from the first direction, the first opening and the second opening at least partially overlap, and the cover covers the first opening and the second opening. The cover includes a cover portion and a protrusion extending from the cover portion toward the electrode assembly. In the first direction, the protrusion extends into the receiving cavity and abuts against a second edge of the second opening. In a second direction perpendicular to the first direction, the plate-like member includes a first portion and a second portion connected to the first portion and extending away from the second direction, the second portion surrounding the protrusion to form a second edge. In the first direction, the distance between the first portion and the cover portion is a first distance, and the distance between the second edge and the cover portion is a second distance, the first distance being different from the second distance.

[0007] In this application, the second part is arranged to extend deviating from the second direction such that D1 > D2 or D1 < D2. Compared with the case where the second part extends along the second direction, the acting force of the second part deviating from the second direction on the convex part is reduced. When gas is generated and continuously accumulates inside the electrochemical device, the convex part is more likely to break away from the second part, the cover body is pushed open, and the gas inside the housing can be released through the second opening and the first opening, so that the pressure in the accommodation cavity drops, improving the reliability and safety of the electrochemical device.

[0008] In some possible implementation manners, the first distance is D1, the second distance is D2, and 1.1D1 ≤ D2 ≤ 1.5D1 or 0.5D1 ≤ D2 ≤ 0.9D1. Thus, the possibility that the gas inside the electrochemical device is not easy to push open the cover body when D2 is too close to D1 can be reduced. At the same time, when the first wall and the plate-shaped member have opposite electrode polarities, the possibility that the plate-shaped member contacts the first wall and causes a short circuit when D2 is small can be reduced.

[0009] In some possible implementation manners, when observed from the first direction, a part of the second edge is located inside the first opening. Therefore, the possibility that the second part is easily bent by the gas and contacts the first wall to cause a short circuit can be reduced.

[0010] In some possible implementation manners, the second part is arranged to be bent towards the cover part compared with the first part. Therefore, the space for accommodating the electrolyte in the accommodation cavity can be increased, which is beneficial to extending the cycle life of the electrochemical device.

[0011] In some possible implementation manners, in the first direction, the first opening and the second opening are arranged separately. Therefore, the possibility that the second part is easily bent by the gas and contacts the first wall to cause a short circuit can be reduced.

[0012] `In some possible implementation manners, the second part is arranged to be bent towards the electrode assembly compared with the first part. Therefore, more of the second layer can be accommodated between the convex part and the second part, which is beneficial to improving the sealing reliability.

[0013] In some possible implementation manners, the thickness of the first part is T1, the thickness of the second part is T2, and T2 < T1. Since the thickness of the second part is relatively thin, under the action of the internal gas, the second part is more likely to separate from the convex part to realize pressure relief in the accommodation cavity.

[0014] In some possible implementation manners, the material of the convex part is aluminum or aluminum alloy, and the material of the plate-shaped member is steel. Since the hardness of the plate-shaped member is greater than that of the convex part, during assembly, it is convenient to embed the convex part into the second opening of the plate-shaped member to form an embedded structure, reducing the deformation of the plate-shaped member caused by the insertion of the convex part, and also maintaining good sealing performance while improving safety and enhancing reliability.

[0015] In some possible implementations, the surface of the plate-like component is provided with an anti-corrosion layer to reduce the likelihood of the plate-like component being corroded by electrolytes such as electrolyte solutions.

[0016] In some possible implementations, when viewed from a second direction, the edge of the protrusion curves and extends along the first direction, thereby improving the sealing reliability of the first or second layer.

[0017] In some possible implementations, a first layer comprising a first insulating material is provided between the cover and the first wall. The first layer is used to seal the gap between the cover and the first wall. When the first wall and the cover have opposite polarities, the first layer also serves to provide electrical insulation between the first wall and the cover to reduce the possibility of a short circuit.

[0018] In some possible implementations, viewed from a first direction, the first layer includes a first region overlapping the cover and a second region separate from the cover. The second region can improve the sealing reliability of the first layer. Furthermore, when the cover and the first wall have opposite polarities, the second region can also reduce the possibility of a short circuit caused by contact between the cover and the first wall. Additionally, when the cover serves as a terminal for connecting external components, the second region can further reduce the possibility of a short circuit caused by contact between the wires connecting the external components and the first wall.

[0019] In some possible implementations, in the first direction, the projection of the first layer onto the cover is located inside the cover. In this case, the amount of the first layer is reduced, and when gas accumulates inside the electrochemical device, the cover is more easily opened after the protrusion detaches from the second part, further improving reliability and safety.

[0020] In some possible implementations, the first insulating material includes at least one of polyethylene, polypropylene, propylene-ethylene copolymer, acrylate, polyetheretherketone, polyvinylidene fluoride, or polytetrafluoroethylene.

[0021] In some possible implementations, the first layer is connected to the protrusion, further improving the sealing reliability of the first layer.

[0022] In some possible implementations, the first layer is connected to the first edge of the first opening, further improving the sealing reliability of the first layer.

[0023] In some possible implementations, a second layer comprising a second insulating material is provided between the first wall and the plate-like member. The second layer serves to seal the gap between the first wall and the plate-like member. Furthermore, when the first wall and the plate-like member have opposite polarities, the second layer also serves to provide electrical insulation between the first wall and the plate-like member to reduce the possibility of a short circuit.

[0024] In some possible implementations, viewed from the first direction, the second layer includes a third region overlapping the plate-like member and a fourth region separate from the plate-like member. The fourth region increases the contact area between the second layer and the first wall, thereby improving the sealing reliability of the second layer. Furthermore, when the first wall and the plate-like member have opposite polarities, the fourth region also reduces the possibility of the first part bending under gas pressure and contacting the first wall, causing a short circuit.

[0025] In some possible implementations, the second insulating material includes at least one of polyethylene, polypropylene, propylene-ethylene copolymer, polyetheretherketone, polyvinylidene fluoride, or polytetrafluoroethylene.

[0026] In some possible implementations, the first layer is connected to the second layer, which helps to further improve the reliability of the seal.

[0027] In some possible implementations, viewed from a first direction, the edge of the first layer away from the protrusion is set separately from the edge of the second layer away from the protrusion.

[0028] In some possible implementations, the second distance is D2, and the length of the protrusion in the first direction is D3, where 0.8D1≤D3≤1.2D1. Therefore, the reliability of the protrusion engaging with the second edge can be improved, and the possibility of the protrusion piercing the electrode assembly when D3 is large, as well as the space occupied by the protrusion within the receiving cavity, can be reduced.

[0029] In some possible implementations, a third layer comprising a third insulating material is provided between the electrode assembly and the plate member. This third layer reduces the likelihood of the protrusion piercing the electrode assembly and causing a short circuit. When the outermost electrode of the electrode assembly is a negative electrode, the third layer also provides electrical insulation between the electrode assembly and the plate member to reduce the risk of a short circuit.

[0030] In some possible implementations, viewed from the first direction, the third layer includes a fifth region overlapping the plate-like member and a sixth region separate from the plate-like member. The sixth region reduces the likelihood of a short circuit caused by contact between the outermost electrode of the electrode assembly and the plate-like member.

[0031] In some possible implementations, the third insulating material includes at least one of polyethylene, polypropylene, propylene-ethylene copolymer, polyetheretherketone, polyvinylidene fluoride, or polytetrafluoroethylene.

[0032] In some possible implementations, the electrochemical device further includes a first conductive plate connected to an electrode assembly. The first conductive plate includes a first connecting portion connected to a protrusion. In a first direction, the first connecting portion is located between the protrusion and a third layer. In this case, the third layer also provides electrical insulation between the first conductive plate and the outermost electrode of the electrode assembly to reduce the risk of short circuits.

[0033] In some possible implementations, the electrochemical device is a coin cell. Coin cells are generally small in size, and the combination of this casing design achieves a balance between sealing and pressure relief, which helps to improve energy density.

[0034] A second aspect of this application also provides an electronic device comprising the aforementioned electrochemical device. The electronic device is powered by the electrochemical device, which has good sealing performance and can release pressure under high pressure, thereby maintaining good reliability and safety. Attached Figure Description

[0035] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0036] Figure 1 This is a top view of an electrochemical device according to one embodiment of this application.

[0037] Figure 2A for Figure 1 The electrochemical device shown is a cross-sectional view along II-II in some embodiments.

[0038] Figure 2B for Figure 2A A partial schematic diagram of the electrochemical device at point A.

[0039] Figure 3A for Figure 2A The diagram shows the structure of the electrochemical device on the IIIA side.

[0040] Figure 3B for Figure 2A The diagram shows the structure of the electrochemical device on the IIIB side.

[0041] Figure 4 for Figure 2A The plate-like components of the electrochemical device shown are schematic diagrams in some embodiments.

[0042] Figure 5 for Figure 2A The schematic diagram of the plate-like components of the electrochemical device shown is presented in some other embodiments.

[0043] Figure 6 for Figure 2A The schematic diagram of the plate-like components of the electrochemical device shown is presented in some other embodiments.

[0044] Figure 7 for Figure 2A The schematic diagram of the plate-like components of the electrochemical device shown is presented in some other embodiments.

[0045] Figure 8 for Figure 2A The schematic diagram of the plate-like components of the electrochemical device shown is presented in some other embodiments.

[0046] Figure 9 for Figure 2A The electrochemical device shown is a partial schematic diagram in some other embodiments.

[0047] Figure 10 for Figure 2A The electrochemical device shown is a partial schematic diagram in some other embodiments.

[0048] Figure 11 for Figure 2A The electrochemical device shown is a partial schematic diagram in some other embodiments.

[0049] Figure 12 for Figure 2A The electrochemical device shown is a partial schematic diagram in some other embodiments.

[0050] Figure 13 for Figure 2A The electrochemical device shown is a partial schematic diagram in some other embodiments.

[0051] Figure 14 for Figure 1 The electrochemical device shown is a partial schematic diagram in some other embodiments.

[0052] Figure 15A This is a cross-sectional view of an electrochemical device according to another embodiment of this application.

[0053] Figure 15B for Figure 15A A partial schematic diagram of the electrochemical device at point B.

[0054] Figure 16 This is a top view of an electrochemical device according to another embodiment of this application.

[0055] Figure 17A for Figure 16 The electrochemical device shown is a cross-sectional view along XVII-XVII.

[0056] Figure 17B for Figure 17A A partial schematic diagram of the electrochemical device at point C.

[0057] Figure 18 This is a schematic diagram of the structure of an electronic device according to one embodiment of this application.

[0058] Explanation of main component symbols

[0059] Electronic device 1

[0060] Casing 10

[0061] First Wall 11

[0062] Second Wall 12

[0063] Electrode assembly 20

[0064] First film 21

[0065] First conductive material layer 21a

[0066] Second conductive material layer 21b

[0067] First conductive layer 21c

[0068] Second pole piece 22

[0069] Third conductive material layer 22a

[0070] Fourth conductive material layer 22b

[0071] Second conductive layer 22c

[0072] Separator 23

[0073] First conductive plate 30

[0074] First conductive part 31

[0075] Second conductive part 32

[0076] Second conductive plate 40

[0077] Third conductive part 41

[0078] Fourth conductive part 42

[0079] Plate-shaped members 50

[0080] Part 1, Chapter 51

[0081] Part 2, Chapter 52

[0082] Anti-corrosion layer 53

[0083] Cover 60

[0084] Cover 61

[0085] Projection 62

[0086] First floor 70

[0087] Area 1, 71

[0088] Second Zone 72

[0089] Second floor 80

[0090] Third District 81

[0091] Fourth District 82

[0092] Third floor 90

[0093] Fifth District 91

[0094] Area 6, 92

[0095] First opening 110

[0096] First edge 110a

[0097] First end 211

[0098] Second end 212

[0099] Third end 221

[0100] Fourth end 222

[0101] Electrochemical devices 100, 200, 300

[0102] First connecting part 310

[0103] Second connecting part 311

[0104] Second opening 500

[0105] Second edge 500a

[0106] First surface 501

[0107] Second surface 502

[0108] Fourth Edge 503

[0109] Third Edge 611

[0110] Fifth Edge 621

[0111] Sixth Edge 701

[0112] Seventh Edge 801

[0113] Eighth Edge 901

[0114] First Division 5021

[0115] Second partition 5022

[0116] First direction X

[0117] Second direction Y

[0118] Receptacle S

[0119] First distance D1

[0120] Second distance D2

[0121] Length D3

[0122] Thicknesses T1 and T2

[0123] Widths W1 and W2

[0124] Boundary line L1~L5

[0125] The following detailed description, in conjunction with the accompanying drawings, will further illustrate this application. Detailed Implementation

[0126] The technical solutions in the embodiments of this application are described clearly and in detail below. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the specification of this application is for the purpose of describing particular embodiments only and is not intended to limit this application.

[0127] The embodiments of this application will be described in detail below. However, this application may 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 to thereby convey this application thoroughly and in detail to those skilled in the art.

[0128] Additionally, for brevity and clarity, the dimensions or thicknesses of various components and layers may be enlarged in the accompanying drawings. Throughout the text, the same numerical values ​​refer to the same elements. As used herein, the terms "and / or" and "and / or" include any and all combinations of one or more of the associated enumerated items. Furthermore, it should be understood that when element A is referred to as "connecting" element B, element A may be directly connected to element B, or there may be an intermediate element C and element A and element B may be indirectly connected to each other.

[0129] Furthermore, when describing the implementation of this application, the word "may" refers to "one or more implementations of this application".

[0130] The technical terms used herein are for the purpose of describing particular embodiments and are not intended to limit this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. It should be further understood that the term "comprising," as used in this specification, means the presence of the described features, values, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, values, steps, operations, elements, components, and / or combinations thereof.

[0131] Spatial terms, such as "above," may be used herein for convenience in describing the relationship between one element or feature and another element (or feature) or feature (or feature) illustrated in the figures. It should be understood that, in addition to the directions depicted in the figures, spatial terms are intended to include different orientations 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" other elements or features would be oriented "below" or "under" other elements or features. Therefore, the exemplary term "above" can include both above and below orientations. It should be understood that although the terms first, second, third, etc., may be used herein to describe various elements, components, regions, layers, and / or portions, these elements, components, regions, layers, and / or portions should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or portion from another element, component, region, layer, or portion. Therefore, a first element, component, region, layer, or portion discussed below may be referred to as a second element, component, region, layer, or portion without departing from the teachings of the exemplary embodiments.

[0132] As used in this article, "parallel" and "perpendicular" are used to describe the ideal state between two components. In actual production or use, two components may exist in a state that is approximately parallel or perpendicular. For example, combined with numerical descriptions, parallel can refer to the angle between two straight lines within ±10°, parallel can also refer to the dihedral angle between two planes within ±10°, and parallel can also refer to the angle between a straight line and a plane within ±10°. Perpendicular can refer to the angle between two straight lines within 90±10°, perpendicular can also refer to the dihedral angle between two planes within 90±10°, and perpendicular can also refer to the angle between a straight line and a plane within 90±10°. The two components described as "parallel" or "perpendicular" do not have to be absolutely straight lines or planes; they can be approximately straight lines or planes. From a macroscopic perspective, if the overall direction of extension is a straight line or plane, the component can be considered a "straight line" or "plane".

[0133] In this application, the design relationships of greater than, less than, or not equal to parameter values ​​need to exclude reasonable errors of the measuring equipment.

[0134] Please see Figure 1 and Figure 2AThis application provides an electrochemical device 100, including a housing 10, an electrode assembly 20, and an electrolyte (not shown). The housing 10 includes a first wall 11, a second wall 12, and a side wall 13. The first wall 11 and the second wall 12 are disposed opposite each other along a first direction X. The first wall 11 may be generally circular, and the second wall 12 may also be generally circular. The first wall 11 and the second wall 12 may be disposed parallel to each other and both perpendicular to the first direction X. One end of the side wall 13 is connected to the first wall 11, and the other end is connected to the second wall 12, so that a generally cylindrical receiving cavity S is formed inside the housing 10. Viewed from the first direction X, the first wall 11 covers the receiving cavity S. The electrode assembly 20 and the electrolyte, such as the electrolyte solution, are contained within the receiving cavity S. The first wall 11 includes a first opening 110, which communicates with the receiving cavity S. In some embodiments, the electrochemical device 100 may be a coin cell, and the housing 10 may be made entirely of steel. In some embodiments, the steel shell includes elements Fe and C, and may also include one or more of the elements Ni, Co, Al, Mn, Cr, Cu, Mg, Mo, S, Si, Ti, V, Pb, Sb, N, and P. Furthermore, the sidewall 13 and the second wall 12 can be integrally formed, and the first wall 11 and the sidewall 13 can be fixed together by welding. In other embodiments, the first wall 11 can be made of an insulating material resistant to electrolyte corrosion, such as polystyrene (PS), polypropylene (PP), polyethylene (PE), polyester (PET), polyvinyl chloride (PVC), polyimide (PI), acrylonitrile-butadiene-styrene plastic (ABS), polycarbonate (PC), polyamide (PA), etc., while the sidewall 13 and the second wall 12 can be made of steel. In this case, the sidewall 13 and the second wall 12 can be integrally formed, and the first wall 11 and the sidewall 13 can be fixed together by snap-fit.

[0135] like Figure 2A As shown, the electrode assembly 20 includes a first electrode 21, a second electrode 22, and a separating film 23 disposed between the first electrode 21 and the second electrode 22. The separating film 23 is used to prevent the first electrode 21 and the second electrode 22 from directly contacting each other, thereby reducing the possibility of a short circuit between the first electrode 21 and the second electrode 22. Figure 2AFor simplicity, the separator 23 is shown as a dashed line (composed of multiple short, spaced lines). In some embodiments, the electrode assembly 20 is a stacked structure, i.e., the first electrode 21, the separator 23, and the second electrode 22 are stacked along a first direction X to form the electrode assembly 20. A second electrode 22 is sandwiched between two adjacent first electrodes 21, and the second electrode 22 and the first electrode 21 are stacked alternately. In the second direction Y, the first electrode 21 includes a first end 211 and a second end 212 disposed opposite to each other, and the second electrode 22 includes a third end 221 and a fourth end 222 disposed opposite to each other. The first end 211 and the third end 221 are located on the same side of the electrode assembly, and the second end 212 and the fourth end 222 are located on the other side of the electrode assembly. In some embodiments, the first electrode 21 is the positive electrode, and the second electrode 22 is the negative electrode. At this time, in order to reduce the possibility of lithium plating on the negative electrode, in the second direction Y, the third end 221 of the second electrode 22 extends beyond the first end 211 of the first electrode 21, and the fourth end 222 of the second electrode 22 extends beyond the second end 212 of the first electrode 21.

[0136] In some embodiments, the first electrode 21 includes a first conductive material layer 21a, a first conductive layer 21c, and a second conductive material layer 21b stacked sequentially. The first conductive layer 21c may have a current-collecting function; for example, the first conductive layer 21c may contain aluminum or nickel. In some embodiments, when the first electrode 21 is a positive electrode, the first conductive layer 21c contains aluminum foil, which has relatively weak strength but good conductivity. Both the first conductive material layer 21a and the second conductive material layer 21b contain an active material, such as at least one of lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, lithium nickel cobalt manganese oxide, lithium iron phosphate, lithium manganese iron phosphate, lithium vanadium phosphate, lithium vanadium oxide phosphate, lithium-rich manganese-based materials, or lithium nickel cobalt aluminum oxide.

[0137] The second electrode 22 includes a third conductive material layer 22a, a second conductive layer 22c, and a fourth conductive material layer 22b stacked together. The second conductive layer 22c may have a current-collecting function; for example, the second conductive layer 22c may contain copper, nickel, or a carbon-based conductive material. In some embodiments, when the second electrode 22 is a negative electrode, the second conductive layer 22c contains copper. Both the third conductive material layer 22a and the fourth conductive material layer 22b contain an active material, which may be selected from at least one of graphite-based materials, alloy materials, lithium metal, and alloys thereof. The graphite-based materials may be selected from at least one of artificial graphite and natural graphite; the alloy materials may be selected from at least one of silicon, silicon oxide, tin, and titanium sulfide.

[0138] The separator 23 includes at least one of polyethylene, polypropylene, polyvinylidene fluoride, polyethylene terephthalate, polyimide, or aramid.

[0139] like Figure 2A and Figure 3BAs shown, the electrochemical device 100 also includes a first conductive plate 30 and a second conductive plate 40. (As indicated...) Figure 2A As shown, the first conductive plate 30 is electrically connected to the first electrode 21, and the second conductive plate 40 is electrically connected to the second electrode 22. Specifically, the first conductive plate 30 is electrically connected to the first conductive layer 21c and extends from the first end 211, and the second conductive plate 40 is electrically connected to the second conductive layer 22c and extends from the fourth end 222. In some embodiments, the first conductive plate 30 includes a first conductive portion 31 and a plurality of second conductive portions 32. The plurality of second conductive portions 32 are respectively connected to the first conductive layers 21c of the plurality of first electrodes 21, and each second conductive portion 32 can be integrally formed or welded to the first conductive layer 21c. The first conductive portion 31 is welded to the plurality of second conductive portions 32. The second conductive plate 40 includes a third conductive portion 41 and a plurality of fourth conductive portions 42. The plurality of fourth conductive portions 42 are respectively connected to the second conductive layers 22c of the plurality of second electrodes 22, and each fourth conductive portion 42 can be integrally formed or welded to the second conductive layer 22c. The third conductive portion is welded to the plurality of fourth conductive portions 42.

[0140] Please refer to the following: Figure 2A , Figure 2B and Figure 3A The electrochemical device 100 also includes a plate-shaped component 50 and a cover 60. The plate-shaped component 50 can be made of a conductive material or an insulating material resistant to electrolyte corrosion. Figure 2B for Figure 2A The diagram shows a partial view of the electrochemical device 100 at point A, which is outlined with a double-dotted line. The cover 60 is made entirely of conductive material. A plate-like member 50 is housed within the receiving cavity S and disposed between the first wall 11 and the electrode assembly 20. The orientation of the first wall 11, the plate-like member 50, and the electrode assembly 20 is the first direction X. The plate-like member 50 includes a second opening 500. Viewed from the second direction Y, the plate-like member 50 includes a first surface 501 facing the first wall 11 and a second surface 502 opposite to the first surface 501. The second opening 500 extends through the first surface 501 and the second surface 502. Viewed from the first direction X, the first opening 110 and the second opening 500 at least partially overlap, and a portion of the second opening 500 may be located within the first edge 110a of the first opening 110. The cover 60 covers the first opening 110 and the second opening 500. In some embodiments, the first opening 110 and the second opening 500 may each be circular. Viewed from the first direction X, the plate-like member 50 may also be circular. In other embodiments, the shapes of the plate member 50, the first opening 110, and the second opening 500 can be changed, such as ellipse, square, hexagon, etc.

[0141] The cover 60 includes a cover portion 61 and a protrusion 62. The cover portion 61 is located outside the housing 10, and in the first direction X, at least a portion of the first wall 11 is located between the cover portion 61 and the electrode assembly 20. The protrusion 62 is formed by extending the cover portion 61 toward the electrode assembly 20. The virtual boundary line between the cover portion 61 and the protrusion 62 is shown by a dashed line L1. A first conductive plate 30 is connected to the protrusion 62, for example, the first conductive portion 31 of the first conductive plate 30 can be connected to the protrusion 62 by welding. A second conductive plate 40 is connected to the housing 10 (for example, when the housing 10 is entirely made of steel, the third conductive portion 41 of the second conductive plate 40 can be connected to the first wall 11, the second wall 12, or the side wall 13 by welding). In some embodiments, the second conductive plate 40 is connected to the second wall 12. In this case, the cover 60 acts as an electrode post, and the cover 60 and the housing 10 exhibit opposite polarities, allowing the electrochemical device 100 to supply power to external components (not shown). When the first electrode 21 is a positive electrode and the second electrode 22 is a negative electrode, the cover 60 is positively polarized and the shell 10 is negatively polarized. For example... Figure 2B As shown, in some embodiments, viewed from the first direction X, in the second direction Y perpendicular to the first direction X, the width W1 of the cover 61 is greater than the width W2 of the protrusion 62, such that the cover 61 can be held against the side of the first wall 11 away from the electrode assembly 20. Viewed from the first direction, the third edge 611 of the cover 61 is separated from the fourth edge 503 of the plate member 50 away from the second opening 500. In some embodiments, the cover 61 and the protrusion 62 can be integrally formed. Viewed from the first direction X, both the cover 61 and the protrusion 62 can be circular. In other embodiments, the cover 61 and the protrusion 62 can also be a separate structure. The shapes of the cover 61 and the protrusion 62 can also be changed, such as elliptical, square, hexagonal, etc.

[0142] In the first direction X, the protrusion 62 extends into the receiving cavity S. The protrusion 62 may be separated from the first edge 110a of the first opening 110, and the protrusion 62 abuts against the second edge 500a of the second opening 500. Specifically, in some embodiments, viewed from the second direction Y, the protrusion 62 has a fifth edge 621 extending along the first direction X, the fifth edge 621 connecting to the cover 61. The fifth edge 621 of the protrusion 62 may be separated from the first edge 110a of the first opening 110, and the fifth edge 621 of the protrusion 62 abuts against the second edge 500a of the second opening 500. Therefore, when the plate member 50 is made of a conductive material, the plate member 50 may exhibit the same polarity as the cover 60. In some embodiments, both the plate member 50 and the cover 60 are made of metal. Specifically, the material of the plate member 50 may be selected from metals such as aluminum, copper, steel, nickel, or their alloys; the material of the cover 60 may be selected from metals such as aluminum, copper, steel, nickel, or their alloys.

[0143] like Figure 2Aand Figure 2B As shown, in the second direction Y, the plate-like member 50 includes a first portion 51 and a second portion 52 connected to the first portion 51. The second portion 52 surrounds the protrusion 62 to form a second edge 500a. The fourth edge 503 of the plate-like member 50 is the edge of the first portion 51 away from the second portion 52. The first portion 51 can extend entirely along the second direction Y. The second portion 52 extends away from the second direction Y, but the second portion 52 does not extend entirely along the first direction X. That is, the second portion 52 is inclined relative to the second direction Y. The virtual boundary line between the first portion 51 and the second portion 52 is shown as a dashed line L2. In the first direction X, the distance between the first portion 51 and the cover portion 61 is a first distance D1, and the distance between the second edge 500a and the cover portion 61 is a second distance D2. The first distance D1 is different from the second distance D2. In some embodiments, D1 and D2 satisfy: D1 > D2.

[0144] In some embodiments, the second part 52 is bent toward the cover part 61 relative to the first part 51, such that D1 > D2. Please refer to [the relevant documentation / reference]. Figure 2A , Figure 2B and Figure 4 Viewed from the second direction Y, the second part 52 located on either side of the convex part 62 can be arc-shaped. Please refer to... Figure 5 In other embodiments, when viewed from the second direction Y, the second portion 52 located on either side of the protrusion 62 can also be flat. It is understood that... Figure 4 and Figure 5 A separate sectional view of the plate-like member 50 is shown, illustrating its structure when viewed along the second direction Y. Due to the provision of the second opening 500, therefore... Figure 4 and Figure 5 The plate-shaped member 50 includes portions located on both sides of the second opening 500, and these two portions can be arranged symmetrically with respect to the second opening 500. However, when viewed from the first direction X, the plate-shaped member 50 can form a continuous ring around the second opening 500, so the dividing line L2 can be arranged in a circle when viewed from the first direction X. For simplicity, the dividing line L2 is only marked on the plate-shaped member 50 located on the side of the protrusion 62.

[0145] like Figure 2BAs shown, in this application, the second part 52 is positioned to extend away from the second direction Y such that D1 > D2. Compared to the case where the second part 52 extends along the second direction Y, the force exerted by the second part 52, which is offset from the second direction Y, on the protrusion 62 is reduced. When gas is generated inside the electrochemical device 100 and continues to accumulate, the protrusion 62 is more likely to detach from the second part 52, the cover 60 is forced open, and the gas inside the housing 10 can be released through the second opening 500 and the first opening 110, thereby reducing the pressure inside the containment cavity S and improving the reliability and safety of the electrochemical device 100. When the second part 52 is bent toward the cover 61, the space available for accommodating the electrolyte in the containment cavity S can also be increased, which helps to extend the cycle life of the electrochemical device 100. When the electrochemical device 100 is a coin cell, since coin cells are generally small in size, the combination of the plate-shaped member 50, the cover 60, and the housing 10 achieves a balance between sealing and pressure relief, which is beneficial to improving energy density.

[0146] In some embodiments, D1 and D2 further satisfy: 0.5D1≤D2≤0.9D1. This reduces the likelihood that the gas inside the electrochemical device 100 will not easily break open the cover 60 when D2 is too close to D1. Simultaneously, when the first wall 11 and the plate-like member 50 have opposite polarities, the possibility of a short circuit caused by contact between the plate-like member 50 and the first wall 11 when D2 is small (i.e., the second part 52 has a greater degree of curvature than the first part 51) can be reduced.

[0147] During assembly, the electrode assembly 20, with the first conductive plate 30 and the second conductive plate 40, is placed in the receiving cavity S, and the second conductive plate 40 is electrically connected to the second wall 12 or the side wall 13. The protrusion 62 of the cover 60 is sequentially inserted into the first opening 110 of the first wall 11 and the second opening 500 of the plate-like member 50, such that the protrusion 62 abuts against the second edge 500a of the second opening 500 to form an embedded structure. Then, the protrusion 62 is electrically connected to the first conductive plate 30, and the first wall 11 is mounted to the side wall 13 to form the housing 10, such that when viewed from the first direction X, the first opening 110 and the second opening 500 at least partially overlap. In some embodiments, the protrusion 62 is made of aluminum or an aluminum alloy, and the plate-like member 50 is made of steel. Because the hardness of the plate-shaped member 50 is greater than that of the protrusion 62, it is easier to embed the protrusion 62 into the second opening 500 of the plate-shaped member 50 during assembly, forming an embedded structure. This reduces the deformation of the plate-shaped member 50 caused by the insertion of the protrusion 62, improving the reliability and safety of the electrochemical device 100. Simultaneously, it also maintains good sealing performance and improves sealing reliability. Furthermore, as... Figure 6As shown, an anti-corrosion layer 53 may be provided on the surface of the plate-shaped member 50. The anti-corrosion layer 53 is used to reduce the possibility of the plate-shaped member 50 being corroded by the electrolyte. The anti-corrosion layer 53 can be a metallic layer, such as a zinc layer, tin layer, copper layer, or chromium layer. The anti-corrosion layer 53 can be formed on the surface of the plate-shaped member 50 by electroplating, chemical plating, or vapor deposition. In other embodiments, the anti-corrosion layer 53 can also be an inorganic coating such as a ceramic layer or a polymer layer.

[0148] like Figure 2A and Figure 2B As shown, in some embodiments, when viewed from the first direction X, a portion of the second edge 500a is located within the first opening 110. Since in some embodiments, the plate-like member 50 and the first wall 11 may have opposite polarities, by positioning a portion of the second edge 500a within the first opening 110, compared to the case where the second edge 500a is outside the first opening 110, this application reduces the likelihood that the second part 52 may easily bend under the influence of gas and come into contact with the first wall 11, causing a short circuit, when gas accumulates inside the electrochemical device 100.

[0149] like Figure 2A and Figure 2B As shown, in some embodiments, the first opening 110 and the second opening 500 are separated in the first direction X. Specifically, in the first direction X, the first opening 110 is located between the cover 61 and the second opening 500. This also reduces the possibility that when gas accumulates inside the electrochemical device 100, the second part 52 may bend under the action of gas and come into contact with the first wall 11, causing a short circuit.

[0150] In some embodiments, the length of the protrusion 62 in the first direction X is D3, where 0.8D2≤D3≤1.2D2. This improves the reliability of the engagement between the protrusion 62 and the second edge 500a, reduces the likelihood that the protrusion 62 will puncture the electrode assembly 20 when D3 is large (e.g., during a crush test), and also reduces the space occupied by the protrusion 62 within the receiving cavity S.

[0151] like Figure 2A and Figure 2BAs shown, in some embodiments, a first layer 70 containing a first insulating material is provided between the cover 61 and the first wall 11. The first layer 70 is used to seal the gap between the cover 61 and the first wall 11, thereby reducing the possibility of electrolyte flowing out of the receiving cavity S through the gap between the cover 61 and the first wall 11 when the electrochemical device 100 is in normal use. Furthermore, when the first wall 11 and the cover 60 have opposite polarities, the first layer 70 also serves to provide electrical insulation between the first wall 11 and the cover 60 to reduce the possibility of a short circuit. It is understood that when gas accumulates inside the electrochemical device 100, causing the protrusion 62 to detach from the second part 52, the first layer 70 will also separate from the cover 60 under the action of the gas, causing the cover 60 to be forced open and achieving pressure relief within the receiving cavity S. In some embodiments, the first insulating material may include at least one of polyethylene, polypropylene, propylene-ethylene copolymer, acrylate, polyetheretherketone, polyvinylidene fluoride, or polytetrafluoroethylene. The first layer 70 can be fixed between the cover 61 and the first wall 11 by an interference fit. In other embodiments, the first layer 70 can also be fixed between the cover 61 and the first wall 11 by means of riveting or the like. Figure 1 As shown, when viewed from the first direction X, the first layer 70 can be circular.

[0152] like Figure 2A and Figure 2B As shown, in some embodiments, in the first direction X, the projection of the first layer 70 onto the cover 61 is located inside the cover 61, and another portion is located outside the cover 61. Therefore, viewed from the first direction X, the first layer 70 includes a first region 71 overlapping the cover 61 and a second region 72 separated from the cover 61. The virtual boundary line between the first region 71 and the second region 72 is shown as a dashed line L3 (the boundary line L3 can be circular when viewed from the first direction X; for simplicity, the boundary line L3 is only marked on the first layer 70 located on the side of the protrusion 62). Providing the second region 72 increases the contact area between the first layer 70 and the first wall 11, thereby improving the sealing reliability of the first layer 70. Moreover, when the cover 60 and the first wall 11 have opposite polarities, the second region 72 can also reduce the possibility of a short circuit caused by contact between the cover 61 and the first wall 11. Furthermore, when the cover 60 is used as a pole to connect external components, the second region 72 can also reduce the possibility of a short circuit caused by contact between the wires connecting the external components and the first wall 11.

[0153] In some embodiments, the first layer 70 may further be connected to the protrusion 62. This further improves the sealing reliability of the first layer 70. Furthermore, the first layer 70 may also be connected to the first edge 110a. This further improves the sealing reliability of the first layer 70.

[0154] like Figure 9As shown, in some embodiments, the first layer 70 may further be connected to the third edge 611 of the cover 61. In this way, the first layer 70 can adequately seal the gap between the cover 61 and the first wall 11 in the first direction X, further improving the sealing reliability of the first layer 70.

[0155] like Figure 10 As shown, in some other embodiments, in the first direction X, the projection of the first layer 70 onto the cover 61 may also be located inside the cover 61. In this case, the amount of the first layer 70 is reduced, and since the contact area between the first layer 70 and the cover 61 is reduced, when gas accumulates inside the electrochemical device 100, the cover 60 is more easily opened after the protrusion 62 disengages from the second part 52, further improving reliability and safety.

[0156] like Figure 2A and Figure 2B As shown, in some embodiments, a second layer 80 containing a second insulating material is provided between the first wall 11 and the plate-like member 50. The second layer 80 is used to seal the gap between the first wall 11 and the plate-like member 50, thereby reducing the possibility of electrolyte flowing out of the receiving cavity S through the gap between the first wall 11 and the plate-like member 50 when the electrochemical device 100 is in normal use. Moreover, when the first wall 11 and the plate-like member 50 have opposite polarities, the second layer 80 also serves to achieve electrical insulation between the first wall 11 and the plate-like member 50 to reduce the possibility of short circuit. When D1 and D2 satisfy 0.5D1≤D2≤0.9D1, the possibility of poor sealing and leakage due to the reduced contact area between the first layer 70 or the second layer 80 and the protrusion 62 is also reduced when D2 is small (i.e., the thickness of the first layer 70 or the second layer 80 is small). It can be understood that the distance D1 between the first part 51 and the cover part 61 is the sum of the thickness of the first layer 70, the thickness of the second layer 80, and the thickness of the first wall 11. One surface of the first wall 11 (such as 2A and Figure 2B The upper surface shown extends along the second direction Y to form a virtual boundary line between the first layer 70 and the second layer 80. In some embodiments, the second insulating material includes at least one of polyethylene, polypropylene, propylene-ethylene copolymer, polyetheretherketone, polyvinylidene fluoride, or polytetrafluoroethylene. The second layer 80 can be fixed between the first wall 11 and the plate-like member 50 by an interference fit. In other embodiments, the second layer 80 can also be fixed between the first wall 11 and the plate-like member 50 by riveting or other means. Figure 1 As shown, when viewed from the first direction X, the second layer 80 can be circular.

[0157] In some embodiments, viewed from the first direction X, the second layer 80 includes a third region 81 overlapping with the plate-like member 50 and a fourth region 82 separated from the plate-like member 50. A virtual boundary line between the third region 81 and the fourth region 82 is shown as a dashed line L4 (the boundary line L4 may be circular when viewed from the first direction X; for simplicity, it is only marked on the second layer 80 located on the side of the protrusion 62). The fourth region 82 increases the contact area between the second layer 80 and the first wall 11, thereby improving the sealing reliability of the second layer 80. Furthermore, if the first wall 11 and the plate-like member 50 have opposite polarities, the fourth region 82 can also reduce the possibility of the first part 51 bending under the influence of gas and contacting the first wall 11, causing a short circuit, when gas accumulates inside the electrochemical device 100. In some embodiments, viewed from the first direction X, the sixth edge 701 of the first layer 70 away from the protrusion 62 is separated from the seventh edge 801 of the second layer 80 away from the protrusion 62.

[0158] In some embodiments, when the first opening 110 and the second opening 500 are separately disposed in the first direction X, the second layer 80 may also be connected to the protrusion 62. This further improves the sealing reliability of the second layer 80. Furthermore, the second layer 80 may also be connected to the first edge 110a. This further improves the sealing reliability of the second layer 80.

[0159] like Figure 2A and Figure 2B As shown, in some embodiments, the first layer 70 and the second layer 80 are connected, which helps to further improve the sealing reliability. Since the protrusion 62 is separated from the first edge 110a of the first opening 110, the first layer 70 and the second layer 80 can be connected within the first opening 110. Furthermore, since the second part 52 is bent towards the cover 61 relative to the first part 51, the second part 52 can compress the portion where the first layer 70 and the second layer 80 are connected, which helps to further improve the sealing reliability. In some embodiments, the first layer 70 and the second layer 80 are an integral structure, and the first insulating material and the second insulating material are made of the same material. In other embodiments, the first insulating material may be different from the second insulating material, and this application is not limiting.

[0160] like Figure 11 As shown, in some other embodiments, the first layer 70 and the second layer 80 may not be connected. In this case, after the protrusion 62 is embedded into the second opening 500 of the plate-shaped member 50 to form an embedded structure during assembly, it is convenient to snap the first layer 70 between the cover 61 and the first wall 11, thereby improving assembly efficiency.

[0161] like Figure 12As shown, in some other embodiments, when viewed from the second direction Y, the fifth edge 621 of the protrusion 62 extends curvedly along the first direction X. For example, the fifth edge 621 can be a curved surface, which helps to increase the contact area between the first layer 70 or the second layer 80 and the protrusion 62, and also helps the plate member 50 to form a snap-fit ​​structure with the first layer 70 or the second layer 80, thereby improving the sealing reliability.

[0162] like Figure 2A and Figure 2B As shown, in some embodiments, a third layer 90 comprising a third insulating material is provided between the electrode assembly 20 and the plate-like member 50. The third layer 90 is used to reduce the possibility of the protrusion 62 piercing the electrode assembly 20 and causing a short circuit, thereby improving the reliability and safety of the electrochemical device 100. When the outermost electrode of the electrode assembly 20 is a negative electrode, the third layer 90 can also provide electrical insulation between the electrode assembly 20 and the plate-like member 50 to reduce the risk of short circuits. The third layer 90 may be generally a flat plate structure. In some embodiments, the third insulating material includes at least one of polyethylene, polypropylene, propylene-ethylene copolymer, polyetheretherketone, polyvinylidene fluoride, or polytetrafluoroethylene. The third insulating material may be the same as or different from the first or second insulating material; this application is not limiting. Figure 1 As shown, viewed from the first direction X, the third layer 90 can be circular. Figure 2A and Figure 2B As shown, in some embodiments, the first conductive portion 31 includes a first connecting portion 310 and a second connecting portion 311 connected together. The first connecting portion 310 is used to connect the protrusion 62, and the second connecting portion 311 is used to connect the second conductive portion 32. In the first direction X, the first connecting portion 310 is located between the protrusion 62 and the third layer 90. Therefore, in the first direction X, the portion of the first conductive portion 31 located between the third layer 90 and the first wall 11 is the first connecting portion 310, and the second connecting portion 311 is the portion of the first conductive portion 31 excluding the first connecting portion 310. The virtual boundary line between the first connecting portion 310 and the second connecting portion 311 is shown as a dashed line L5. When the first conductive plate 30 is positive and the outermost electrode of the electrode assembly 20 is negative, since the first connecting portion 310 is located between the protrusion 62 and the third layer 90, the third layer 90 can also provide electrical insulation between the first conductive plate 30 and the outermost electrode of the electrode assembly 20 to reduce the risk of short circuit.

[0163] In some embodiments, viewed from the first direction X, the third layer 90 includes a fifth region 91 overlapping with the plate-like member 50 and a sixth region 92 separated from the plate-like member 50. The fifth region 91 includes, in addition to the region where the second layer 80 overlaps with the first portion 51 and the second portion 52 of the plate-like member 50, the region also includes the region overlapping with the second opening 500 of the plate-like member 50. The sixth region 92 extends from the region overlapping with the second opening 500 of the plate-like member 50 along the second direction Y to the region overlapping with the second portion 52 and the first portion 51 of the plate-like member 50, and further extends beyond the first portion 51 of the plate-like member 50. When the outermost electrode of the electrode assembly 20 is a negative electrode, providing the sixth region 92 can reduce the possibility of a short circuit caused by the outermost electrode of the electrode assembly 20 contacting the plate-like member 50 when the electrochemical device 100 is dropped, shaken, or impacted. In some embodiments, viewed from the first direction X, the seventh edge 801 of the second layer 80 away from the protrusion 62 is separated from the eighth edge 901 of the third layer 90. Combined with reference Figure 1 and Figure 2A In the second direction Y, the eighth edge 901 of the third layer 90 may extend beyond the third end 221 and the fourth end 222 of the second electrode 22 of the electrode assembly 20.

[0164] like Figure 2A and Figure 2B As shown, in some embodiments, in the first direction X, the first portion 51 of the plate-like member 50, the first connecting portion 310 of the first conductive plate 30, the third layer 90, and the electrode assembly 20 are spaced apart. That is, there is a gap between each adjacent pair of the first portion 51 of the plate-like member 50, the first connecting portion 310 of the first conductive plate 30, the third layer 90, and the electrode assembly 20. This facilitates the housing of the electrode assembly 20 within the housing 10, and the aforementioned gaps can also be used to accommodate more electrolyte. Figure 13 As shown, in some other embodiments, the first portion 51 of the plate-like member 50, the first connecting portion 310 of the first conductive plate 30, the third layer 90, and the electrode assembly 20 may also be in contact in the first direction X. This reduces the shaking of the electrode assembly 20 within the housing 10 in the event of mechanical abuse such as drops or impacts to the electrochemical device 100. Figure 14 As shown, in other embodiments, when the length of the protrusion 62 increases by D3, the protrusion 62 can also push against the first connecting portion 310, causing the first connecting portion 310, the third layer 90, and the electrode assembly 20 to come into contact. This also reduces the shaking of the electrode assembly 20 within the housing 10 during mechanical abuse.

[0165] like Figure 4 and Figure 5As shown, in some embodiments, the thickness of the first part 51 is T1, and the thickness of the second part 52 is T2. T2 can be equal to T1. At this time, it is relatively easy to form the plate-like member 50. For example, processes such as laser cutting and machining can be used to cut the plate-like member 50 into the required shape, and then stamping is used to form the bent second part 52 in the middle of the plate-like member 50.

[0166] For example Figure 7 and Figure 8 As shown, in some other embodiments, T2 < T1. Since the thickness of the second part 52 is relatively thin, under the action of the internal gas, the second part 52 is more likely to separate from the convex part 62, realizing the pressure relief of the accommodation cavity S. It can be understood that the thickness T1 of the first part 51 is the distance between the first surface 501 and the second surface 502 of the first part 51. When the first part 51 extends as a whole along the second direction Y, the thickness T1 is the thickness of the first part 51 in the first direction X. The thickness T2 of the second part 52 is the distance between the first surface 501 and the second surface 502 of the first part 51, and the second part 52 deviates from the second direction Y in extension, so the thickness T2 is the thickness of the second part 52 deviating from the first direction X. The thicknesses T1 and T2 can be measured using a laser rangefinder or a micrometer.

[0167] Furthermore, in some embodiments, such as Figure 7 As shown, the second surface 502 is a stepped surface, which includes a first partition 5021 located in the first part 51 and a second partition 5022 located in the second part 52. The first partition 5021 and the second partition 5022 can both be parallel to the first surface 501, and the second partition 5022 is closer to the first surface 501 than the first partition 5021, making T2 < T1. Such as Figure 8 As shown, in some other embodiments, along the extension direction of the plate-like member 50 (i.e., from the first part 51 to the second part 52), the thickness of the second part 52 gradually decreases. Therefore, the maximum thickness of the second part 52 can be equal to the thickness T1 of the first part 51, the minimum thickness of the second part 52 can be any value less than T1, and the minimum thickness of the second part 52 can also be zero. Therefore, when T2 < T1 is defined, T2 actually refers to the average thickness of the second part 52. Among them, the average thickness of the second part 52 can be measured in the following way: Along the extension direction of the plate-like member 50, use a laser rangefinder or a micrometer to measure the thickness of the second part 52 every 1 mm, and obtain multiple thickness values. The thickness T2 is the average value of the above multiple thickness values.

[0168] Please refer to Figure 15A and 15B , another embodiment of the present application also provides an electrochemical device 200, where Figure 15B is Figure 15AThe diagram shows a partial view of the electrochemical device 200 at point B, which is outlined with a double-dotted line. The electrochemical device 200 differs from the electrochemical device 100 described above in the structure of the plate-shaped member 50. In this embodiment, D1 < D2.

[0169] In some embodiments, the second part 52 is bent toward the electrode assembly 20 relative to the first part 51, such that D1 < D2. In this application, the second part 52 is positioned to extend away from the second direction Y, such that D1 < D2. When gas accumulates inside the electrochemical device 200, the force exerted by the second part 52, which is deviated from the second direction Y, on the protrusion 62 is also smaller. Therefore, the protrusion 62 disengages from the second part 52, the cover 60 is opened, and the gas inside the housing 10 can flow out through the second opening 500 and the first opening 110, thus depressurizing the containment cavity S, reducing the possibility of an explosion in the electrochemical device 200, and improving reliability and safety. Simultaneously, compared to the electrochemical device 100, because the second part 52 is bent toward the electrode assembly 20, more of the second layer 80 can be accommodated between the protrusion 62 and the second part 52, which is beneficial for improving sealing reliability.

[0170] In some embodiments, D1 and D2 further satisfy: 1.1D1≤D2≤1.5D1. This reduces the likelihood that the gas inside the electrochemical device 100 will have difficulty opening the cover 60 when D2 is too close to D1. Simultaneously, it reduces the likelihood that when D2 is large (i.e., the second part 52 has a larger degree of curvature compared to the first part 51), the plate-shaped member 50 will occupy a larger space inside the housing 10, reducing energy density. It also reduces the likelihood that when D2 is large, the reliability of the engagement between the plate-shaped member 50 and the protrusion 62 will decrease, leading to leakage.

[0171] Please see Figure 16 , Figure 17A and Figure 17B Another embodiment of this application also provides an electrochemical device 300, wherein... Figure 17B for Figure 17A The diagram shows a partial view of the electrochemical device 300 at point C, where point C is outlined with a double-dotted line. The electrochemical device 300 differs from the electrochemical device 100 described above in the structure of the electrode assembly 20. In this embodiment, the electrode assembly 20 has a wound structure, meaning that the first electrode 21, the separator 23, and the second electrode 22 are stacked and wound around a winding center axis O arranged along the first direction X to form the electrode assembly 20. In this case, along the first direction X, the first electrode 21 includes a first end 211 and a second end 212 disposed opposite to each other, and the second electrode 22 includes a third end 221 and a fourth end 222 disposed opposite to each other. Both the first end 211 and the third end 221 face the first wall 11.

[0172] Further, in some embodiments, the first conductive plate 30 is connected to the first end 211 and further connected to the protrusion 62. The second conductive plate 40 is connected to the fourth end 222 and further connected to the housing 10. To facilitate the connection of the first conductive plate 30 to the housing 10 after extending from the first end 211, viewed along the first direction X, the eighth edge 901 of the third layer 90 is separated from the outermost electrode of the electrode assembly 20 (such as the second electrode 22). And in the second direction Y, the eighth edge 901 of the third layer 90 does not extend beyond the outermost electrode of the electrode assembly 20. Figure 16 and Figure 17A As shown, in some embodiments, the outermost layer of the electrode assembly 20 may be a second electrode 22, and the innermost layer of the electrode assembly 20 may be a separator 23.

[0173] like Figure 17A As shown, in some embodiments, the first conductive plate 30 may include only one first conductive portion 31, with its two ends connected to the first electrode 21 and the protrusion 62, respectively. The second conductive plate 40 may include only one third conductive portion 41, with its two ends connected to the second electrode 22 and the housing 10, respectively. In other embodiments, the first conductive plate 30 may also include one first conductive portion 31 and multiple second conductive portions (not shown). The multiple second conductive portions are respectively connected to the first conductive layer 21c of the first electrode 21, and the first conductive portion 31 is welded and fixed to the multiple second conductive portions. The second conductive plate 40 may also include one third conductive portion 41 and multiple fourth conductive portions (not shown). The multiple fourth conductive portions are respectively connected to the second conductive layer 22c of the second electrode 22, and the third conductive portion is welded and fixed to the multiple fourth conductive portions.

[0174] The electrochemical devices 100, 200, and 300 of this application include all devices capable of undergoing electrochemical reactions. Specifically, electrochemical devices 100, 200, and 300 include all types of primary batteries, secondary batteries, fuel cells, solar cells, and capacitors (e.g., supercapacitors). Optionally, electrochemical devices 100, 200, and 300 can be lithium secondary batteries, including lithium metal secondary batteries, lithium-ion secondary batteries, lithium polymer secondary batteries, and lithium-ion polymer secondary batteries.

[0175] Please see Figure 18, an embodiment of the present application further provides an electronic device 1, including the above-mentioned electrochemical device 100 (or electrochemical devices 200, 300). The electronic device 1 is powered by the above-mentioned electrochemical device 100. The electrochemical device 100 has good sealing performance, and the electrochemical device 100 can release pressure under a large pressure state, thereby maintaining good reliability and safety. 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 power-assisted bicycle, 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. <00004​​​​​​​​​​​​​​​​​​​​​​The difference from Embodiment 1 is that the second part 52 of the plate member 50 does not extend in the second direction Y, that is, the ratio of D2 to D1 is 1.

[0183] One hundred batteries from each embodiment and comparative example were subjected to drop tests and hotbox tests, and the corresponding test results are recorded in Table 1.

[0184] The drop test procedure is as follows:

[0185] 1) Charge the battery to 100% SOC (State of Charge) under ambient conditions of 25±5℃;

[0186] 2) Place the battery into the clamping chamber and use an automatic drop device to drop the bottom, side and top of the battery onto the steel plate in sequence from a position of 1.8m, for a total of 6 rounds or 18 drops;

[0187] 3) Calculate the percentage of batteries that leak.

[0188] The hotbox testing procedure is as follows:

[0189] 1) Under an ambient temperature of 25±5℃, discharge the battery to 3.0V at 0.2C, let it stand for 5 minutes, and then charge it to 4.48V at a constant current and constant voltage of 1.5C with a current ≤0.05C;

[0190] 2) Then place the battery in a hot box and raise it to 150℃±2℃ at a rate of 5℃±2℃ / min, and maintain it for 60 minutes. Observe whether the battery depressurizes normally.

[0191] 3) Calculate the percentage of batteries with poor pressure relief.

[0192] Table 1

[0193] Comparative Example 1 15 / 100 0 / 100 Example 1 0.9 0 / 100 0 / 100 Example 2 0.8 0 / 100 0 / 100 Example 3 0.7 0 / 100 0 / 100 Example 4 0.6 0 / 100 0 / 100 Example 5 0.5 0 / 100 0 / 100 Example 6 0.4 0 / 100 13 / 100 Example 7 1.1 0 / 100 0 / 100 Example 8 1.2 0 / 100 0 / 100 Example 9 1.3 0 / 100 0 / 100 Example 10 1.4 0 / 100 0 / 100 Example 11 1.5 0 / 100 0 / 100 Example 12 1.6 0 / 100 10 / 100

[0194] Note: The poor pressure relief ratio X / 100 indicates that out of 100 samples tested, X samples had poor pressure relief. The meaning of the leakage ratio is the same.

[0195] As shown in Table 1, compared to the comparative examples, Examples 1-12, due to the inclusion of a second part 52 extending away from the second direction Y, allowed the second part 52 to disengage from the protrusion 62 during the hot box test, thus achieving pressure relief and improving battery reliability and safety. Compared to Examples 1-5, the proportion of leakage is relatively higher in Example 6 because the D2:D1 ratio is relatively small. Compared to Examples 7-11, the proportion of leakage is also relatively higher in Example 12 because the D2:D1 ratio is relatively large.

[0196] The above-disclosed embodiments are merely preferred embodiments of this application and should not be construed as limiting the scope of this application. Therefore, any equivalent variations made in accordance with this application are still within the scope of this application.

Claims

1. An electrochemical device comprising a housing and an electrode assembly, the housing having a receiving cavity and a first wall covering the receiving cavity, the first wall including a first opening, the electrode assembly being housed within the receiving cavity; wherein, The electrochemical device further includes a plate-shaped member and a cover, the plate-shaped member being housed within the receiving cavity and disposed between the first wall and the electrode assembly, the plate-shaped member including a second opening; The direction in which the plate-shaped member and the electrode assembly are arranged is defined as a first direction. When viewed from the first direction, the first opening and the second opening at least partially overlap, and the cover covers the first opening and the second opening. The cover includes a cover portion and a protrusion extending from the cover portion toward the electrode assembly. In the first direction, the protrusion extends into the receiving cavity and abuts against the second edge of the second opening. In a second direction perpendicular to the first direction, the plate-like member includes a first portion and a second portion connected to the first portion and extending away from the second direction, the second portion surrounding the protrusion to form a second edge; in the first direction, the distance between the first portion and the cover portion is a first distance, and the distance between the second edge and the cover portion is a second distance, the first distance and the second distance being different; The first distance is D1, the second distance is D2, and 1.1D1 ≤ D2 ≤ 1.5D1, or 0.5D1 ≤ D2 ≤ 0.9D1.

2. The electrochemical device of claim 1, wherein, Viewed from the first direction, a portion of the second edge is located within the first opening.

3. The electrochemical device of claim 1, wherein, The second part is bent toward the cover portion relative to the first part.

4. The electrochemical device of claim 3, wherein, In the first direction, the first opening and the second opening are separated.

5. The electrochemical device of claim 1, wherein, The second part is bent toward the electrode assembly compared to the first part.

6. The electrochemical device of claim 1, wherein, The thickness of the first part is T1, and the thickness of the second part is T2, where T2 < T1.

7. The electrochemical device of claim 1, wherein, The protrusion is made of aluminum or aluminum alloy, and the plate-shaped component is made of steel.

8. The electrochemical device of claim 7, wherein, The surface of the plate-shaped component is provided with an anti-corrosion layer.

9. The electrochemical device of claim 1, wherein, Viewed from the second direction, the edge of the protrusion extends and curves along the first direction.

10. The electrochemical device of claim 1, wherein, A first layer containing a first insulating material is provided between the cover and the first wall.

11. The electrochemical device of claim 10, wherein, Viewed from the first direction, the first layer includes a first region that overlaps with the cover and a second region that is separate from the cover.

12. The electrochemical device of claim 10, wherein, In the first direction, the projection of the first layer onto the cover is located within the cover.

13. The electrochemical device of claim 10, wherein, The first insulating material includes at least one of polyethylene, polypropylene, propylene-ethylene copolymer, acrylate, polyetheretherketone, polyvinylidene fluoride, or polytetrafluoroethylene.

14. The electrochemical device of claim 10, wherein, The first layer is connected to the protrusion.

15. The electrochemical device of claim 10, wherein, The first layer is connected to the first edge of the first opening.

16. The electrochemical device of claim 10, wherein, A second layer containing a second insulating material is provided between the first wall and the plate-like member.

17. The electrochemical device of claim 16, wherein, Viewed from the first direction, the second layer includes a third region overlapping the plate-like member and a fourth region separate from the plate-like member.

18. The electrochemical device of claim 16, wherein, The second insulating material includes at least one of polyethylene, polypropylene, propylene-ethylene copolymer, polyetheretherketone, polyvinylidene fluoride, or polytetrafluoroethylene.

19. The electrochemical device of claim 16, wherein, The first layer is connected to the second layer.

20. The electrochemical device of claim 16, wherein, Viewed from the first direction, the edge of the first layer away from the protrusion is separated from the edge of the second layer away from the protrusion.

21. The electrochemical device of claim 1, wherein, The second distance is D2, and the length of the protrusion in the first direction is D3, where 0.8D2 ≤ D3 ≤ 1.2D2.

22. The electrochemical device as claimed in claim 1, wherein, A third layer comprising a third insulating material is provided between the electrode assembly and the plate-shaped member.

23. The electrochemical device of claim 22, wherein, Viewed from the first direction, the third layer includes a fifth region that overlaps with the plate-like member and a sixth region that is separate from the plate-like member.

24. The electrochemical device of claim 22, wherein, The third insulating material includes at least one of polyethylene, polypropylene, propylene-ethylene copolymer, polyetheretherketone, polyvinylidene fluoride, or polytetrafluoroethylene.

25. The electrochemical device of claim 22, wherein, The electrochemical device further includes a first conductive plate connected to the electrode assembly. The first conductive plate includes a first connecting portion connected to the protrusion. In the first direction, the first connecting portion is located between the protrusion and the third layer.

26. The electrochemical device as claimed in claim 1, wherein, The electrochemical device is a coin cell.

27. An electronic device comprising an electrochemical device as claimed in any one of claims 1 to 26.

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