Electrochemical apparatus and electrical device

Abstract

The present application discloses an electrochemical apparatus and an electrical device. The electrochemical apparatus comprises a housing and an electrode assembly, the housing comprising a first housing part and a second housing part having different polarities. The electrode assembly comprises a pole piece assembly, a first tab and a second tab, the pole piece assembly comprising a first pole piece and a second pole piece configured in a wound manner, the first tab being connected to the first pole piece and the first housing part, and the second tab being connected to the second pole piece and the second housing part. The electrochemical device further comprises a first connecting piece, the first connecting piece comprising a first arc-shaped part and satisfying: 30°≤γ+(10.95×(R1 / R0)3-31.0144×(R1 / R0)2+28.88×(R1 / R0)-7.012)×β1≤180°; and / or the electrochemical device further comprises a second connecting piece, the second connecting piece comprising a second arc-shaped part and satisfying: 30°≤γ-(10.95×(R2 / R0)3-31.0144×(R2 / R0)2+28.88×(R2 / R0)-7.012)×β2≤180°. The present application helps reduce the axial magnetic field at the end surface of the wound pole piece assembly, thereby reducing interference of the electrochemical apparatus on the electrical device.

Description

Electrochemical devices and electrical equipment Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to an electrochemical device and electrical equipment. Background Art

[0002] Due to the unique spiral involute structure of wound batteries, a strong axial magnetic field is generated at the end faces of the wound structure. This can significantly interfere with electrical devices such as Bluetooth headsets, affecting their normal operation. Therefore, how to reduce the axial magnetic field of wound batteries has become an urgent problem.

[0003] Summary of the Invention

[0004] In view of this, the present application provides an electrochemical device to reduce the axial magnetic field of a wound structure battery, thereby reducing the interference of the electrochemical device on electrical equipment.

[0005] In a first aspect, the present application provides an electrochemical device, comprising a housing and an electrode assembly, the housing comprising a first shell portion and a second shell portion having different polarities. The electrode assembly is housed in the housing, and the electrode assembly comprises a pole piece assembly, a first pole tab, and a second pole tab. The pole piece assembly comprises a first pole piece and a second pole piece arranged in a wound manner, the first pole piece comprising a first current collector and a first active layer located on the surface of the first current collector, the second pole piece comprising a second current collector and a second active layer located on the surface of the second current collector; the winding start section of the first active layer is located on the winding inner side of the pole piece assembly relative to the winding start section of the second active layer. The first pole tab connects the first region of the winding tail section of the first current collector and the first housing portion. The second pole tab connects the second region of the winding tail section of the second current collector and the second housing portion, and along the winding direction of the pole piece assembly from the inside to the outside, the first region extends beyond the second region. Observed along the width direction of the first electrode sheet, along the winding direction of the electrode sheet assembly from the inside to the outside, the angle between the ray from the winding center of the electrode sheet assembly to the center of the second region and the ray from the winding center to the center of the first region is θ; when the winding length of the first region exceeding the second region is less than one turn, γ=θ; when the winding length of the first region exceeding the second region is greater than or equal to one turn, and the number of complete turns of the first region exceeding the second region is n, γ=360°×n+θ; the distance from the winding center of the electrode sheet assembly to the center of the first region is R0; the electrochemical device satisfies at least one of the following conditions:

[0006] (1) The electrochemical device further includes a first connector located outside the housing, the first connector including a first end connected to the first housing, a second end for connecting to an external load, and a first arc-shaped portion located between the first end and the second end; the first arc-shaped portion includes a first inner edge close to the winding center of the pole piece assembly and a first outer edge away from the winding center, and the distance from the winding center to the first inner edge is R11 , the distance from the winding center to the first outer edge is R 12 , the equivalent radius R1 of the first arc portion is (R 11 +R 12 ) / 2. Along the extension direction from the first end to the second end, the first arc-shaped portion includes a first starting end and a first ending end; when the extension direction from the first starting end to the first ending end is the same as the winding direction of the pole piece assembly from the inside to the outside, along the winding direction of the pole piece assembly from the inside to the outside, the angle between the ray from the winding center of the pole piece assembly to the first starting end and the ray from the winding center to the first ending end is α1, and β1=α1 is defined; when the extension direction from the first starting end to the first ending end is opposite to the winding direction of the pole piece assembly from the inside to the outside, along the opposite direction of the winding direction of the pole piece assembly from the inside to the outside, the angle between the ray from the winding center of the pole piece assembly to the first starting end and the ray from the winding center to the first ending end is α1, and β1=-α1 is defined; satisfying: 30°≤γ+(10.95×(R1 / R0) 3 -31.0144×(R1 / R0) 2 +28.88×(R1 / R0)-7.012)×β1≤180°.

[0007] (2) The electrochemical device further includes a second connector located outside the housing, the second connector including a third end connected to the second housing, a fourth end for connecting to an external load, and a second arc-shaped portion located between the third end and the fourth end; the second arc-shaped portion includes a second inner edge close to the winding center of the electrode assembly and a second outer edge away from the winding center, and the distance from the winding center to the second inner edge is R 21 , the distance from the winding center to the second outer edge is R 22 , the equivalent radius R2 of the second arc portion is (R 21 +R 22 ) / 2. Along the extension direction from the third end to the fourth end, the second arc-shaped portion includes a second starting end and a second end; when the extension direction from the second starting end to the second end is the same as the winding direction of the pole piece assembly from the inside to the outside, along the winding direction of the pole piece assembly from the inside to the outside, the angle between the ray from the winding center of the pole piece assembly to the second starting end and the ray from the winding center to the second end is α2, and β2=α2 is defined; when the extension direction from the second starting end to the second end is opposite to the winding direction of the pole piece assembly from the inside to the outside, along the opposite direction of the winding direction of the pole piece assembly from the inside to the outside, the angle between the ray from the winding center of the pole piece assembly to the second starting end and the ray from the winding center to the second end is α2, and β2=-α2 is defined. Satisfies: 30°≤γ-(10.95×(R2 / R0) 3 -31.0144×(R2 / R0) 2 +28.88×(R2 / R0)-7.012)×β2≤180°.

[0008] The inventors of this application discovered through research that since the pole piece assembly of the winding structure has a special structure of a spiral involute, the effective current path length of the first pole piece on the inner side of the winding will be smaller than the effective current path of the second pole piece on the outer side of the winding, thereby generating a stronger axial magnetic field at the end face of the pole piece assembly. On the one hand, the present application extends the effective length of the first pole piece located on the inner side of the winding so that the first area exceeds the second area. When the electrode assembly discharges and generates current, the magnetic field generated by the portion of the first pole piece exceeding the second area can at least partially offset the axial magnetic field generated by the spiral involute structure. On the other hand, by providing a first arc portion in the first connector and / or providing a second arc portion in the second connector, and controlling the central angle β1 of the first arc portion and its equivalent radius R1 and the angle γ of the first area exceeding the second area to meet the above condition (1) and / or, when the central angle β2 of the second arc portion and its equivalent radius R2 and the angle γ of the first area exceeding the second area meet the above condition (2), the first arc portion and / or the second arc portion can supplement the deficiency of the portion of the first pole piece exceeding the second area in offsetting the axial magnetic field, and eliminate the excessive offset of the portion of the first pole piece exceeding the second area in offsetting the axial magnetic field. Moreover, since the first arc portion and / or the second arc portion are outside the shell, they can better offset the axial magnetic field on the end face of the winding structure, thereby helping to reduce the interference of the electrochemical device on the electrical equipment.

[0009] In some embodiments, when the electrochemical device satisfies condition (1), it further satisfies: 60°≤γ+(10.95×(R1 / R0) 3 -31.0144×(R1 / R0) 2 +28.88×(R1 / R0)-7.012)×β1≤120°. In this way, the axial magnetic field at the end surface of the winding structure can be further reduced, thereby further reducing interference with electrical equipment.

[0010] In some embodiments, when the electrochemical device satisfies condition (2), it also satisfies: 60°≤γ-(10.95×(R2 / R0) 3 -31.0144×(R2 / R0) 2 +28.88×(R2 / R0)-7.012)×β2≤120°. In this way, the axial magnetic field at the end surface of the winding structure can be further reduced, thereby further reducing interference with electrical equipment.

[0011] In some embodiments, the first pole ear includes a first connecting portion and a first bending portion, the first connecting portion is connected to the first region, the first bending portion is bent toward the first end face of the pole piece assembly, and along the width direction of the first pole piece, the first bending portion is located on one side of the pole piece assembly, and the first bending portion is connected to the first shell portion.

[0012] In some embodiments, the second pole ear includes a second connecting portion and a second bending portion, the second connecting portion is connected to the second region, the second bending portion is bent toward the second end face of the pole piece assembly, the second end face and the first end face are arranged opposite to each other along the width direction of the first pole piece, and along the width direction of the first pole piece, the second bending portion is located on the side of the pole piece assembly away from the first bending portion.

[0013] In some embodiments, the first bent portion includes a third region connected to the first shell portion, and the angle η between a ray from the center of the third region to the center of the first region and a ray from the center of the third region to the first starting end satisfies η ≤ 45°. This helps reduce the impact of current passing through the first bent portion on the axial magnetic field, thereby further reducing interference with electrical equipment.

[0014] In some embodiments, the second shell portion includes a fourth region connected to the second bend, and the angle δ between a ray from the center of the fourth region to the center of the second region and a ray from the center of the fourth region to the second starting end satisfies δ≤45°. This helps reduce the impact of current passing through the second bend on the axial magnetic field, thereby further reducing interference with electrical equipment.

[0015] In some embodiments, the first shell portion includes a top wall, a bottom wall, and side walls, the second shell portion includes a pole, the top wall is provided with a through hole, and the pole is provided in the through hole.

[0016] In some embodiments, the first connecting member is disposed on the first end surface side, thereby reducing the axial magnetic field on the first end surface side, thereby reducing interference of the first end surface side on the electrical equipment.

[0017] In some embodiments, the second connecting member is provided on the second end surface side, so that the axial magnetic field on the second end surface side can be reduced, thereby reducing the interference of the second end surface side on the electrical equipment.

[0018] In some embodiments, along the winding direction of the pole piece assembly from the inside out, the winding tail section of the first current collector includes a blank section that extends beyond the first region and is not provided with the first active layer on its surface. This blank section covers the winding tail section of the second current collector. Thus, the blank section of the first current collector is provided between the winding tail section of the second current collector and the first shell, which helps to enhance the isolation between the second current collector and the first shell, thereby reducing the risk of short circuit caused by direct contact between the second current collector and the first shell.

[0019] In some embodiments, 30°≤γ≤450°. This is more conducive to achieving the offsetting effect of the portion of the first pole piece that extends beyond the second region. In some embodiments, 30°≤γ≤180°. In some embodiments, 60°≤γ≤150°.

[0020] In some embodiments, 15°≤α1≤210°. This is more conducive to the offsetting effect of the first arc portion. In some embodiments, 15°≤α1≤45°. In some embodiments, 60°≤α1≤120°. In some embodiments, 150°≤α1≤210°.

[0021] In some embodiments, 15°≤α2≤210°. This is more conducive to the offsetting effect of the second arc portion. In some embodiments, 15°≤α2≤45°. In some embodiments, 60°≤α2≤120°. In some embodiments, 150°≤α2≤210°.

[0022] In some embodiments, the winding length of the first region extending beyond the second region is less than one turn, which helps to reduce the extension length of the first current collector, thereby reducing the risk of the first current collector extending too long and being easily misaligned and causing a short circuit.

[0023] In some embodiments, the first electrode is a negative electrode and the second electrode is a positive electrode; wherein the first active layer's winding start section extends beyond the second active layer's winding start section in the opposite direction of the electrode assembly's winding direction from the inside out, and / or the first active layer's winding end section extends beyond the second active layer's winding end section in the electrode assembly's winding direction from the inside out. This helps reduce the risk of lithium plating and improves the safety of the electrochemical device.

[0024] In some embodiments, the electrode assembly further includes a first diaphragm, which is disposed between the first electrode and the second electrode. As the electrode assembly is wound from the inside out, the first diaphragm extends beyond the first electrode. Thus, the first diaphragm covers the first electrode, thereby reducing the risk of direct contact between the first and second electrode sheets.

[0025] In some embodiments, the electrode assembly further includes a second diaphragm disposed between the first electrode and the second electrode. The second diaphragm extends beyond the second electrode along the winding direction of the electrode assembly from the inside out. This allows the second diaphragm to cover the winding tail of the second electrode, thereby reducing the risk of direct contact between the second electrode and the first electrode or the housing.

[0026] In some embodiments, the electrochemical device further includes an insulating member disposed between the housing and the pole piece assembly, thereby reducing the risk of direct contact between the pole piece assembly and the housing, thereby reducing the risk of internal short circuits in the electrochemical device.

[0027] In a second aspect, the present application further provides an electrical device comprising an electrochemical device as described in any of the above embodiments. The electrochemical device in the above embodiments has a reduced axial magnetic field, thereby reducing electromagnetic interference to the electrical device and improving the reliability of the electrical device. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG1 is a schematic diagram of an electrical device provided in an embodiment of the present application.

[0029] FIG2 is a schematic structural diagram of an electrochemical device provided in one embodiment of the present application.

[0030] FIG3 is a partial cross-sectional view of an electrochemical device provided in one embodiment of the present application.

[0031] FIG4 is a schematic diagram of the winding of a pole piece assembly provided in one embodiment of the present application.

[0032] FIG5 is a schematic structural diagram of an electrode assembly provided in one embodiment of the present application.

[0033] FIG6 is a top view of an electrochemical device provided in one embodiment of the present application.

[0034] FIG7 is a top view of an electrochemical device provided in another embodiment of the present application.

[0035] FIG8 is a top view of an electrochemical device with a hidden first shell portion provided by an embodiment of the present application.

[0036] FIG9 is a schematic diagram of the winding of a pole piece assembly provided in another embodiment of the present application.

[0037] Description of Main Component Symbols Electrochemical Device 100 Housing 10 First Shell 11 Accommodating Space 11a Top Wall 111 Through Hole 1111 Bottom Wall 112 Side Wall 113 Second Shell 12 Mounting Portion 121 Lead-Out Portion 122 Fourth Region 123 Electrode Assembly 20 Pole Plate Assembly 21 First End Surface 21a Second End Surface 21b First Pole Plate 211 First Current Collector 2111 First Region 211a Blank Section 211b First Active Layer 2112 Second Pole Plate 212 Second Current Collector 2121 Second Region 212a Second Active Layer 2122 First Tab 22 First Connecting Portion 221 First Bend 222 Third Region 222a Second Tab 23 Second Connecting Portion231 Second bend 232 First diaphragm 24 Second diaphragm 25 First connector 30 First end 31 Second end 32 First arcuate portion 33 First inner edge 33a First outer edge 33b First starting end 331 First terminal 332 Second connector 40 Third end 41 Fourth end 42 Second arcuate portion 43 Second inner edge 43a Second outer edge 43b Second starting end 431 Second terminal 432 Sealing member 50 Winding center D Width direction of first pole piece X Winding direction of pole piece assembly from inside to outside C Device body 200 Electrical device 1000 DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present application will be described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0039] It should be noted that in this application, the "center of the region" means that when the region is a continuous whole, the center of the region is the center of gravity of the plane shape of the region. It can be understood that the center of gravity of the plane shape can be determined by the hanging method. The plane shape is suspended with a thin line, and a straight line is drawn in the vertical direction from the starting point of the thin line. The plane shape is suspended again with a different endpoint from the first time, and another straight line is drawn according to the previous method. The intersection of the two straight lines is the center of gravity of the plane shape; when the region is composed of multiple discrete regions, the center of the region is the center of the minimum circumscribed circle containing the multiple discrete regions. It can be understood that the minimum circumscribed circle is the circle with the smallest radius that contains the multiple discrete regions. When a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be a central component at the same time. When a component is considered to be "located on" another component, it can be directly located on the other component or there may be a central component at the same time. The terms "top", "bottom", "upper", "lower", "left", "right", "front", "back", and similar expressions used herein are for illustrative purposes only.

[0040] The terms "first", "second", etc. are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implying the quantity, specific order or primary and secondary relationship of the technical features indicated.

[0041] The term "parallel" is used to describe an ideal state between two components. In actual production or use, two components can be approximately parallel. Two components described as "parallel" do not necessarily need to be absolutely straight lines or planes; they can be roughly straight lines or planes. From a macroscopic perspective, a component is considered "straight" or "planar" if its overall extension is a straight line or plane.

[0042] It should be understood that the sizes and thicknesses of the components shown in the drawings are for better understanding and more convenient description, and the present application is not limited to the sizes and thicknesses shown in the drawings.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0044] The following will describe some embodiments of the present application in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.

[0045] Referring to FIG. 1 , an embodiment of the present application provides an electrical device 1000 , which includes an electrochemical device 100 .

[0046] In some embodiments, referring to FIG. 1 , the power-consuming device 1000 further includes a device body 200 , and the electrochemical device 100 is installed in the device body 200 to supply power to the device body 200 .

[0047] In some embodiments, the power-consuming device 1000 may be a Bluetooth headset, a Bluetooth speaker, a mobile phone, a laptop computer, a tablet computer, an e-book player, an electric toy, a game console, a video recorder, a portable recorder, a radio, a smart watch, a lighting lamp, or a calculator, etc., which are not listed here one by one.

[0048] In some embodiments, referring to Figures 2 and 3 , an electrochemical device 100 includes a housing 10 and an electrode assembly 20, wherein the electrode assembly 20 is housed within the housing 10. The electrode assembly 20 includes a pole piece assembly 21, a first pole tab 22, and a second pole tab 23, wherein both the first pole tab 22 and the second pole tab 23 are connected to the pole piece assembly 21.

[0049] In some embodiments, referring to FIG. 3 , the housing 10 includes a first housing portion 11 and a second housing portion 12 . The first housing portion 11 and the second housing portion 12 have different polarities and are insulated from each other.

[0050] In some embodiments, referring to FIG3 , the first shell portion 11 includes a top wall 111, a bottom wall 112, and side walls 113. The side walls 113 are located between the top wall 111 and the bottom wall 112. The top wall 111 and the bottom wall 112 are both connected to the side walls 113, and enclose a receiving space 11a for accommodating the electrode assembly 20. The first shell portion 11 can protect the electrode assembly 20 and reduce the risk of external impact to the electrode assembly 20.

[0051] In some embodiments, referring to FIG. 3 , the second shell portion 12 includes a pole, and a top wall 111 is provided with a through hole 1111 . The pole is provided in the through hole 1111 and is insulated and connected to the top wall 111 .

[0052] In some embodiments, referring to FIG3 , the electrode post includes a mounting portion 121 and a lead portion 122. The mounting portion 121 is located within the accommodating space 11a and connected to the electrode assembly 20. The mounting portion 121 is also insulated from the top wall 111. The lead portion 122 is disposed through the through hole 1111 and is at least partially exposed outside the accommodating space 11a.

[0053] In some embodiments, referring to FIG. 3 , the electrochemical device 100 further includes a sealing member 50 . The sealing member 50 is disposed between the top wall 111 and the mounting portion 121 to insulate and seal the mounting portion 121 from the top wall 111 .

[0054] In some embodiments, the seal 50 may be a sealant.

[0055] In some embodiments, the pole can be made of a conductive metal such as copper, aluminum, nickel, or iron. The pole can be in the shape of a column, a hemisphere, a sheet, or a combination thereof, and is not specifically limited here.

[0056] In some embodiments, referring to Figures 4 and 5 , the electrode assembly 21 includes a first electrode 211 and a second electrode 212 that are wound together. Along the width direction X of the first electrode 211, the wound electrode assembly 21 includes a first end face 21a and a second end face 21b that are opposite to each other. The first electrode 211 has a first polarity, and the second electrode 212 has a second polarity, where the first polarity and the second polarity are different. For example, the first electrode 211 is a negative electrode, and the second electrode 212 is a positive electrode; in another example, the first electrode 211 is a positive electrode, and the second electrode 212 is a negative electrode.

[0057] Referring to Figure 4 , the first electrode 211 includes a first current collector 2111 and a first active layer 2112 located on the surface of the first current collector 2111. The second electrode 212 includes a second current collector 2121 and a second active layer 2122 located on the surface of the second current collector 2121. The first current collector 2111 and the second current collector 2121 may be metal layers. For example, the first electrode 211 is a negative electrode. The first current collector 2111 may be a metal layer including at least one of copper, nickel, tantalum, titanium, and the like, such as copper foil. The first active layer 2112 includes a negative electrode active material, which may include at least one of graphite, hard carbon, soft carbon, silicon, a silicon-oxygen material, and a silicon-carbon material. The second electrode sheet 212 is a positive electrode sheet, and the second current collector 2121 can be a metal layer including at least one of aluminum, nickel, tantalum, titanium, etc., such as aluminum foil; the first active layer 2112 includes a positive electrode active material, and the positive electrode active material can include at least one of lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium iron phosphate, lithium manganese iron phosphate or lithium manganese oxide, etc.

[0058] In some embodiments, referring to Figures 3 and 4 , the first electrode piece 211 is connected to the first electrode tab 22, which is connected to the first shell 11, so that the first electrode tab 22 and the first shell 11 have a first polarity. The second electrode piece 212 is connected to the second electrode tab 23, which is connected to the second shell 12, so that the second electrode tab 23 and the second shell 12 have a second polarity.

[0059] In some embodiments, referring to FIG. 4 , the winding start section of the first active layer 2112 is located on the inner side of the winding of the pole piece assembly 21 relative to the winding start section of the second active layer 2122 .

[0060] In some embodiments, referring to Figures 4 and 5 , the first electrode tab 22 includes a first connecting portion 221 and a first bent portion 222. The first connecting portion 221 is connected to the first region 211a of the winding tail section of the first current collector 2111. It is understood that the first region 211a is the region where the first current collector 2111 and the first connecting portion 221 are connected. Generally, the first region 211a has a certain planar shape. When the planar shape of the first region 211a is a continuous whole, the center of the first region 211a is defined as the center of gravity of the planar shape of the first region 211a. When the first region 211a is composed of multiple discrete regions (for example, the first current collector 2111 and the first connecting portion 221 are connected by multiple discrete point-like regions), the center of the first region 211a is defined as the center of the smallest circumscribed circle containing the multiple discrete regions. The first bending portion 222 is bent toward the first end surface 21 a of the pole piece assembly 21 . The first bending portion 222 is located on one side of the pole piece assembly 21 along the width direction X of the first pole piece 211 . The first bending portion 222 is connected to the first shell portion 11 .

[0061] In some embodiments, referring to FIG. 5 , the first bent portion 222 extends in a direction parallel to the first end surface 21 a .

[0062] In some embodiments, the first connection portion 221 and the first current collector 2111 can be connected by welding, bonding or pressing, and the first bending portion 222 and the first shell 11 can be connected by welding, bonding or pressing, which are not specifically limited here.

[0063] In some embodiments, referring to Figures 4 and 5, the second electrode tab 23 includes a second connecting portion 231 and a second bent portion 232, wherein the second connecting portion 231 is connected to the second region 212a of the winding tail section of the second current collector 2121. It can be understood that the second region 212a is the region where the second current collector 2121 is connected to the second connecting portion 231, wherein the method for determining the center of the second region 212a is the same as the method for determining the center of the first region 211a, and will not be repeated here. The second bent portion 232 is bent toward the second end face 21b of the electrode assembly 21, along the width direction X of the first electrode 211, and is located on the side of the electrode assembly 21 away from the first bent portion 222, and the second bent portion 232 is connected to the second shell 12.

[0064] In some embodiments, referring to FIG. 5 , the second bent portion 232 extends in a direction parallel to the second end surface 21 b .

[0065] In some embodiments, the second connection portion 231 and the second current collector 2121 may be connected by welding, bonding or pressing, and the second bending portion 232 and the second shell 12 may be connected by welding, bonding or pressing, which are not specifically limited here.

[0066] In some embodiments, referring to FIG. 4 , when viewed along the width direction X of the first electrode 211 and along the winding direction C from the inside to the outside of the electrode assembly 21, the angle between the ray from the winding center D of the electrode assembly 21 to the center of the second region 212a and the ray from the winding center D to the center of the first region 211a is θ; when the winding length of the first region 211a exceeding the second region 212a is less than one turn, γ=θ; when the winding length of the first region 211a exceeding the second region 212a is less than one turn, γ=θ; When the number of complete turns that is greater than or equal to one turn and the first area 211a exceeds the second area 212a is n, γ = 360° × n + θ. For example, when the winding length of the first area 211a exceeding the second area 212a is equal to one turn, the number of complete turns n that the first area 211a exceeds the second area 212a is 1, θ = 0°, then γ = 360° × 1 + 0° = 360°; the distance from the winding center D of the pole piece assembly 21 to the center of the first area 211a is R0.

[0067] In some embodiments, 30°≤γ≤450°. This is more conducive to the offsetting effect of the portion of the first pole piece 211 that extends beyond the second region 212a. For example, γ can be 30°, 45°, 60°, 90°, 120°, 150°, 180°, 210°, 240°, 270°, 300°, 330°, 360°, 390°, 420°, 450°, or a range consisting of any two of the above. In some embodiments, 30°≤γ≤180°. In some embodiments, 60°≤γ≤150°.

[0068] Implementation Method 1

[0069] 6 , the electrochemical device 100 further includes a first connector 30 located outside the housing 10 . The first connector 30 includes a first end 31 connected to the first shell 11 , a second end 32 for connecting to an external load, and a first arcuate portion 33 located between the first end 31 and the second end 32 .

[0070] The first arc-shaped portion 33 includes a first inner edge 33a close to the winding center D of the pole piece assembly 21 and a first outer edge 33b away from the winding center D. The distance from the winding center D to the first inner edge 33a is R 11 The distance from the winding center D to the first outer edge 33b is R 12 , the equivalent radius R1 of the first arc-shaped portion 33 is (R 11 +R 12) / 2.

[0071] The inventors of this application have discovered that the magnetic fields generated by the first arc-shaped portion 33 and the pole piece assembly 21 within the same arc range are not the same. Taking the electrical device 1000 as a Bluetooth headset as an example, the magnetic field strength of the pole piece assembly 21 and the first arc-shaped portion 33 is solved using finite element software based on Maxwell's equations. The first arc-shaped portion 33 and the first pole piece 211 or the second pole piece 212 corresponding to the pole piece assembly 21 with the same radius are selected, the current is set to 1A, the magnetic field strength is normalized, and the magnetic field strength of the pole piece assembly 21 is used as a reference to obtain the relationship shown in Table 1 below:

[0072] Table 1: Comparison of magnetic field strength between the first arc portion 33 and the pole piece assembly 21 at the same arc

[0073] Among them, n1 represents the first magnetic field strength coefficient of the first arc-shaped portion 33, and the first magnetic field strength coefficient represents the ratio of the magnetic field strength of the first arc-shaped portion 33 and the pole piece assembly 21 at the Bluetooth headset voice coil when the Bluetooth headset voice coil and the first arc-shaped portion 33 are arranged on the same side of the pole piece assembly 21.

[0074] The magnetic field intensities of the first arc-shaped portions 33 with different equivalent radii are normalized to obtain the data shown in Table 2 below:

[0075] Table 2: Effect of the equivalent radius of the first arc portion 33 on the magnetic field intensity

[0076] Wherein, R1 represents the equivalent radius of the first arc-shaped portion 33; R0 represents the radius of the pole piece assembly 21, that is, the distance from the winding center D of the pole piece assembly 21 to the center of the first region 211a; n2 represents the second magnetic field intensity coefficient of the first arc-shaped portion 33. The second magnetic field intensity coefficient represents the coefficient of variation of the first magnetic field intensity when the ratio of the equivalent radius R1 of the first arc-shaped portion 33 to the radius R0 of the pole piece assembly 21 is different.

[0077] The second magnetic field intensity coefficient n2, the equivalent radius R1 of the first arc-shaped portion 33, and the radius R0 of the pole piece assembly 21 are fitted to obtain the relationship: n2 = 6.066 × (R / R0) 3 -17.1825×(R / R0) 2 +16×(R / R0)-3.885.

[0078] Continuing with FIG6 , along the extension direction from the first end 31 to the second end 32, the first arcuate portion 33 includes a first starting end 331 and a first end 332. When the extension direction from the first starting end 331 to the first end 332 is the same as the winding direction C of the pole piece assembly 21 from the inside to the outside, along the winding direction C of the pole piece assembly 21 from the inside to the outside, the angle between the ray from the winding center D of the pole piece assembly 21 to the first starting end 331 and the ray from the winding center D to the first end 332 is α1, and β1 is defined as α1. When the extension direction from the first starting end 331 to the first end 332 is opposite to the winding direction C of the pole piece assembly 21 from the inside to the outside, along the opposite direction of the winding direction C of the pole piece assembly 21 from the inside to the outside, the angle between the ray from the winding center D of the pole piece assembly 21 to the first starting end 331 and the ray from the winding center D to the first end 332 is α1, and β1 is defined as -α1.

[0079] Satisfies: 30°≤γ+n1×n2×β1≤150°.

[0080] That is, 30°≤γ+(10.95×(R1 / R0) 3 -31.0144×(R1 / R0) 2 +28.88×(R1 / R0)-7.012)×β1≤150°.

[0081] The inventors of the present application have discovered that, due to the special structure of the spiral involute of the wound pole piece assembly 21, the effective current path length of the first pole piece 211 on the inner side of the winding is smaller than the effective current path of the second pole piece 212 on the outer side of the winding, thereby generating a stronger axial magnetic field at the end face of the pole piece assembly 21. On the one hand, the present application extends the effective length of the first pole piece 211 located on the inner side of the winding so that the first region 211a exceeds the second region 212a. When the electrode assembly 20 discharges and generates current, the magnetic field generated by the portion of the first pole piece 211 that exceeds the second region 212a can at least partially offset the axial magnetic field generated by the spiral involute structure; on the other hand, by providing a first arc portion 33 in the first connecting member 30, and controlling the central angle β1 of the first arc portion 33 and its equivalent radius R1 and the angle γ of the first region 211a exceeding the second region 212a to satisfy: 30°≤γ+(10.95×(R1 / R0) 3 -31.0144×(R1 / R0) 2+28.88×(R1 / R0)-7.012)×β1≤150°, the first arc-shaped portion 33 can supplement the insufficient offset of the axial magnetic field by the portion of the first pole piece 211 that exceeds the second area 212a, and eliminate the excessive offset of the axial magnetic field by the portion of the first pole piece 211 that exceeds the second area 212a. Moreover, since the first arc-shaped portion 33 is outside the shell 10, the offset effect of the axial magnetic field on the end face of the winding structure is greatly enhanced, which is beneficial to reducing the interference of the electrochemical device 100 on the electrical equipment 1000.

[0082] For example, γ+(10.95(R1 / R0) 3 -31.0144(R1 / R0) 2 The value of β1 can be 30°, 45°, 60°, 75°, 90°, 105°, 120°, 135°, 150°, or a range of any two of the above. In some embodiments, 60°≤γ+(10.95×(R1 / R0) 3 -31.0144×(R1 / R0) 2 +28.88×(R1 / R0)−7.012)×β1≤120°. In this way, the axial magnetic field at the end surface of the winding structure can be further reduced, thereby further reducing interference to the electrical device 1000.

[0083] In some embodiments, 15°≤α1≤210°. This is more conducive to the offsetting effect of the first curved portion 33. For example, α1 can be 15°, 30°, 45°, 60°, 75°, 90°, 105°, 120°, 135°, 150°, 180°, 210°, or a range consisting of any two of the foregoing. In some embodiments, 15°≤α1≤45°. In some embodiments, 60°≤α1≤120°. In some embodiments, 150°≤α1≤210°.

[0084] In some embodiments, referring to FIG. 3 , the first connector 30 is disposed on the first end face 21 a side. This helps reduce the axial magnetic field on the first end face 21 a side, and facilitates the connection between the first connector 30 and the first shell portion 11 , thereby reducing the risk of a short circuit with the second shell portion 12 .

[0085] In some other embodiments, the first connecting member 30 is disposed on the second end surface 21 b side, which is beneficial for reducing the axial magnetic field on the second end surface 21 b side.

[0086] In some embodiments, referring to Figures 5 and 6 , the first bent portion 222 includes a third region 222a connected to the first shell portion 11. The angle η between a ray from the center of the third region 222a to the center of the first region 211a and a ray from the center of the third region 222a to the first starting end 331 satisfies η ≤ 45°. This helps reduce the impact of current passing through the first bent portion 222 on the axial magnetic field, thereby further reducing interference with the electrical device 1000. The method for determining the center of the third region 222a is similar to the method for determining the center of the first region 211a and will not be repeated here.

[0087] Implementation Method 2

[0088] Referring to FIG. 7 , the electrochemical device 100 further includes a second connector 40 located outside the housing 10. The second connector 40 includes a third end 41 connected to the second housing 12, a fourth end 42 for connecting to an external load, and a second arcuate portion 43 located between the third end 41 and the fourth end 42. The second arcuate portion 43 includes a second inner edge 43a close to the winding center D of the electrode assembly 21 and a second outer edge 43b away from the winding center D. The distance from the winding center D to the second inner edge 43a is R. 21 The distance from the winding center D to the second outer edge 43b is R 22 , the equivalent radius R2 of the second arc-shaped portion 43 is (R 21 +R 22 ) / 2.

[0089] In which, along the extension direction from the third end 41 to the fourth end 42, the second arcuate portion 43 includes a second starting end 431 and a second end 432; when the extension direction from the second starting end 431 to the second end 432 is the same as the winding direction C of the pole piece assembly 21 from the inside to the outside, along the winding direction C of the pole piece assembly 21 from the inside to the outside, the angle between the ray from the winding center D of the pole piece assembly 21 to the second starting end 431 and the ray from the winding center D to the second end 432 is α2, and β2 = α2 is defined. When the extension direction from the second starting end 431 to the second end 432 is opposite to the winding direction C of the pole piece assembly 21 from the inside to the outside, along the opposite direction of the winding direction C of the pole piece assembly 21 from the inside to the outside, the angle between the ray from the winding center D of the pole piece assembly 21 to the second starting end 431 and the ray from the winding center D to the second end 432 is α2, and β2 = -α2 is defined.

[0090] Satisfies: 30°≤γ-n1×n2×β2≤150°.

[0091] That is, 30°≤γ-(10.95×(R2 / R0) 3 -31.0144×(R2 / R0) 2+28.88×(R2 / R0)-7.012)×β2≤150°.

[0092] The principle is the same as that of the first embodiment. The central angle β2 of the second arc portion 43 and its equivalent radius R2 and the angle γ of the first area 211a extending beyond the second area 212a satisfy the following conditions: 30°≤γ-(10.95×(R2 / R0) 3 -31.0144×(R2 / R0) 2 When the condition of +28.88×(R2 / R0)-7.012)×β2≤150° is met, the effect of offsetting the axial magnetic field at the end face of the winding structure can be greatly improved, thereby helping to reduce the interference of the electrochemical device 100 on the electrical equipment 1000.

[0093] For example, γ-(10.95×(R2 / R0) 3 -31.0144×(R2 / R0) 2 The value of β2 can be 30°, 45°, 60°, 75°, 90°, 105°, 120°, 135°, 150°, or a range of any two of the above. In some embodiments, 60°≤γ-(10.95×(R2 / R0) 3 -31.0144×(R2 / R0) 2 +28.88×(R2 / R0)−7.012)×β2≤120°. In this way, the axial magnetic field at the end surface of the winding structure can be further reduced, thereby further reducing interference to the electrical device 1000.

[0094] In some embodiments, 15°≤α2≤210°. This is more conducive to the offsetting effect of the second curved portion 43. For example, α2 can be 15°, 30°, 45°, 60°, 75°, 90°, 105°, 120°, 135°, 150°, 180°, 210°, or a range consisting of any two of the foregoing. In some embodiments, 15°≤α2≤45°. In some embodiments, 60°≤α2≤120°. In some embodiments, 150°≤α2≤210°.

[0095] In some embodiments, referring to FIG. 3 , the second connector 40 is disposed on the second end face 21 b side. This helps reduce the axial magnetic field on the second end face 21 b side and facilitates the connection between the second connector 40 and the second shell portion 12 , thereby reducing the risk of a short circuit with the first shell portion 11 .

[0096] In some other embodiments, the second connecting member 40 is disposed on the side of the first end surface 21 a , which is beneficial for reducing the axial magnetic field on the side of the first end surface 21 a .

[0097] In some embodiments, referring to Figures 7 and 8 , the second shell portion 12 includes a fourth region 123 connected to the second bent portion 232. The angle δ between a ray from the center of the fourth region 123 to the center of the second region 212a and a ray from the center of the fourth region 123 to the second starting end 431 satisfies δ ≤ 45°, which helps reduce the impact of current passing through the second bent portion 232 on the axial magnetic field, thereby further reducing interference with the electrical device 1000. The method for determining the center of the fourth region 123 is similar to the method for determining the center of the first region 211a and is not further described here.

[0098] In some embodiments, referring to FIG. 4 and FIG. 9 , the winding length of the first region 211a beyond the second region 212a is less than one turn, which helps to reduce the extended length of the first current collector 2111, thereby reducing the risk of the first current collector 2111 extending too long and being easily dislocated and causing a short circuit.

[0099] In some embodiments, referring to FIG9 , along the winding direction C from the inside to the outside of the pole piece assembly 21, the winding tail section of the first current collector 2111 includes a blank section 211b that extends beyond the first region 211a and is not provided with the first active layer 2112 on its surface. The blank section 211b covers the winding tail section of the second current collector 2121. This arrangement provides the blank section 211b of the first current collector 2111 between the winding tail section of the second current collector 2121 and the first shell 11, thereby enhancing the isolation between the second current collector 2121 and the first shell 11, thereby reducing the risk of short circuits caused by direct contact between the second current collector 2121 and the first shell 11.

[0100] In some embodiments, referring to Figures 4 and 9 , the first electrode 211 is a negative electrode, the second electrode 212 is a positive electrode, and along the direction opposite to the winding direction C of the electrode assembly 21 from the inside to the outside, the winding start section of the first active layer 2112 extends beyond the winding start section of the second active layer 2122. Furthermore, along the winding direction C of the electrode assembly 21 from the inside to the outside, the winding end section of the first active layer 2112 extends beyond the winding end section of the second active layer 2122. This helps reduce the risk of lithium plating and improves the safety of the electrochemical device 100.

[0101] In some embodiments, referring to Figures 4 and 9, the pole piece assembly 21 further includes a first diaphragm 24, which is disposed between the first pole piece 211 and the second pole piece 212. Along the winding direction C from the inside to the outside of the pole piece assembly 21, the winding tail section of the first diaphragm 24 exceeds the first pole piece 211, so that the winding tail end of the first pole piece 211 is covered by the first diaphragm 24, which helps to reduce the risk of direct contact between the first pole piece 211 and the second pole piece 212.

[0102] In some embodiments, referring to Figures 4 and 9, the electrode assembly 21 further includes a second diaphragm 25, which is disposed between the first electrode 211 and the second electrode 212. Along the winding direction C from the inside to the outside of the electrode assembly 21, the winding tail section of the second diaphragm 25 exceeds the second electrode 212, allowing the winding tail section of the second electrode 212 to be covered by the second diaphragm 25, which helps to reduce the risk of direct contact between the second electrode 212 and the first electrode 211 or the shell 10.

[0103] In some embodiments, along the winding direction C from the inside to the outside of the pole piece assembly 21, the winding tail section of the first diaphragm 24 and / or the second diaphragm 25 is fixed to the main body of the pole piece assembly 21 by gluing with adhesive tape, which helps to reduce the risk of curling of the winding tail section of the first diaphragm 24 and / or the second diaphragm 25.

[0104] 4 and 9 , the second electrode piece 212 is located between the first diaphragm 24 and the second diaphragm 25. In other embodiments, the first electrode piece 211 is located between the first diaphragm 24 and the second diaphragm 25.

[0105] In some embodiments, the first diaphragm 24 and the second diaphragm 25 can be made of materials such as polyethylene (PE) or polypropylene (PP), and are used to isolate the first electrode piece 211 from the second electrode piece 212 .

[0106] In some embodiments, the electrochemical device 100 further includes an insulating member (not shown) disposed between the housing 10 and the electrode assembly 21. This helps reduce the risk of direct contact between the electrode assembly 21 and the housing 10, thereby reducing the risk of internal short circuits in the electrochemical device 100.

[0107] In order to verify the effect of the present application on canceling the axial magnetic field of the electrochemical device 100, the following comparative tests were conducted:

[0108] Taking a Bluetooth headset assembled with a cylindrical steel-shell battery with a wound structure as an example, along the winding direction C from the inside to the outside of the electrode assembly 21, starting from the overlapping part of the negative electrode active layer and the positive electrode active layer at the beginning of the winding, and ending at the overlapping part of the negative electrode active layer and the positive electrode active layer at the end of the winding, there are a total of 18 layers. The first electrode 211 is the negative electrode, the negative electrode tab is connected to the bottom wall 112 of the shell, and the positive electrode tab is connected to the pole. Three types of electrode assemblies 20 are prepared, one electrode assembly 20 satisfies: γ = 450°, one electrode assembly 20 satisfies: γ = 270°, and one electrode assembly 20 satisfies: γ = 90°. The radius R0 of the steel-shell battery is 5 mm. A first connector 30 connected to the bottom wall 112 is provided on the side of the bottom wall 112 of the shell 10. The inner edge radius R of the first arc-shaped portion 33 in the first connector 30 is 11 =3.4mm, outer edge radius R 12=4.7mm, then the equivalent radius R1 of the first arc-shaped portion 33 is 4.05mm, or a second connector 40 connected to the pole is provided on the top wall 111 side of the housing 10, and the inner edge radius R of the second arc-shaped portion 43 in the second connector 40 is 21 =3.4mm, outer edge radius R 22 =4.7mm, then the equivalent radius R2 of the second arc portion 43 = 4.05mm. At this point, n1×n2=1.851, so γ+n1×n2×β1=γ+1.851β1; γ-n1×n2×β2=γ-1.851β2. The central angle β1 of the first arc portion 33 or the central angle β2 of the second arc portion 43 were adjusted, and the current sound level of the Bluetooth headset voice coil on the corresponding side was tested. The test results are shown in Table 3:

[0109] Table 3: Current sound levels of Bluetooth headsets at different γ, β1, and β2

[0110] Among them, the smaller the sound, the lower the decibel, and 0dB is the smallest sound that the human ear can hear.

[0111] From the comparison in Table 3, it can be seen that when the steel shell battery meets 30°≤γ+(10.95×(R1 / R0) 3 -31.0144×(R1 / R0) 2 +28.88×(R1 / R0)-7.012)×β1≤180°, or 30°≤γ-(10.95×(R2 / R0) 3 -31.0144×(R2 / R0) 2 +28.88×(R2 / R0)-7.012)×β2≤180°, the Bluetooth headset has a lower current sound level. Furthermore, when 60°≤γ+(10.95×(R1 / R0) 3 -31.0144×(R1 / R0) 2 When +28.88×(R1 / R0)-7.012)×β1≤120°, the current sound level of the Bluetooth headset can be further significantly reduced.

[0112] In addition, those skilled in the art should recognize that the above embodiments are only used to illustrate the present application and are not used to limit the present application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. An electrochemical device, characterized in that include: The shell comprises a first shell portion and a second shell portion having different polarities; An electrode assembly is housed in the housing, and the electrode assembly comprises: A pole piece assembly, comprising a first pole piece and a second pole piece arranged in a wound manner, wherein the first pole piece comprises a first current collector and a first active layer located on a surface of the first current collector, and the second pole piece comprises a second current collector and a second active layer located on a surface of the second current collector; a winding start section of the first active layer is located on a winding inner side of the pole piece assembly relative to a winding start section of the second active layer; A first electrode tab, the first electrode tab connecting a first region of the first current collector winding tail section and the first shell; A second pole ear, the second pole ear is connected to the second region of the winding tail section of the second current collector and the second shell portion, and along the winding direction of the pole piece assembly from inside to outside, the first region exceeds the second region; Observing along the width direction of the first pole piece, along the winding direction of the pole piece assembly from the inside to the outside, the angle between the ray from the winding center of the pole piece assembly to the center of the second region and the ray from the winding center to the center of the first region is θ; when the winding length of the first region exceeding the second region is less than one circle, γ=θ; when the winding length of the first region exceeding the second region is greater than or equal to one circle, and the number of complete circles of the first region exceeding the second region is n, γ=360°×n+θ; the distance from the winding center of the pole piece assembly to the center of the first region is R0; The electrochemical device satisfies at least one of the following conditions: (1) The electrochemical device further comprises a first connector located outside the housing, the first connector comprising a first end connected to the first housing, a second end for connecting to an external load, and a first arc-shaped portion located between the first end and the second end; the first arc-shaped portion comprises a first inner edge close to the winding center of the pole piece assembly and a first outer edge away from the winding center, and the distance from the winding center to the first inner edge is R 11 , the distance from the winding center to the first outer edge is R 12 , the equivalent radius R1 of the first arc portion is (R 11 +R 12 ) / 2; Along the extension direction from the first end to the second end, the first arc portion includes a first starting end and a first end; when the extension direction from the first starting end to the first end is the same as the winding direction of the pole piece assembly from the inside to the outside, along the winding direction of the pole piece assembly from the inside to the outside, the angle between the ray from the winding center of the pole piece assembly to the first starting end and the ray from the winding center to the first end is α1, and β1=α1 is defined; when the extension direction from the first starting end to the first end is opposite to the winding direction of the pole piece assembly from the inside to the outside, along the opposite direction of the winding direction of the pole piece assembly from the inside to the outside, the angle between the ray from the winding center of the pole piece assembly to the first starting end and the ray from the winding center to the first end is α1, and β1=-α1 is defined; Satisfies: 30°≤γ+(10.95×(R1 / R0) 3 -31.0144×(R1 / R0) 2 +28.88×(R1 / R0)-7.012)×β1≤180°; (2) The electrochemical device further comprises a second connecting member located outside the housing, wherein the second connecting member The connecting member includes a third end connected to the second shell portion, a fourth end for connecting to an external load, and a second arc portion located between the third end and the fourth end; the second arc portion includes a second inner edge close to the winding center of the pole piece assembly and a second outer edge away from the winding center, and the distance from the winding center to the second inner edge is R 21 , the distance from the winding center to the second outer edge is R 22 , the equivalent radius R2 of the second arc portion is (R 21 +R 22 ) / 2; Along the extension direction from the third end to the fourth end, the second arc portion includes a second starting end and a second end; when the extension direction from the second starting end to the second end is the same as the winding direction of the pole piece assembly from the inside to the outside, along the winding direction of the pole piece assembly from the inside to the outside, the angle between the ray from the winding center of the pole piece assembly to the second starting end and the ray from the winding center to the second end is α2, and β2=α2 is defined; when the extension direction from the second starting end to the second end is opposite to the winding direction of the pole piece assembly from the inside to the outside, along the opposite direction of the winding direction of the pole piece assembly from the inside to the outside, the angle between the ray from the winding center of the pole piece assembly to the second starting end and the ray from the winding center to the second end is α2, and β2=-α2 is defined; Satisfy: 30°≤γ-(10.95×(R2 / R0) 3 -31.0144×(R2 / R0) 2 +28.88×(R2 / R0)-7.012)×β2≤180°.

2. The electrochemical device according to claim 1, characterized in that The electrochemical device satisfies at least one of the following conditions: (1) 60°≤γ+(10.95×(R1 / R0) 3 -31.0144×(R1 / R0) 2 +28.88×(R1 / R0)-7.012)×β1≤120°; (2)60°≤γ-(10.95×(R2 / R0) 3 -31.0144×(R2 / R0) 2 +28.88×(R2 / R0)-7.012)×β2≤120°.

3. The electrochemical device according to claim 1, characterized in that The first pole ear includes a first connecting portion and a first bending portion, the first connecting portion is connected to the first region, the first bending portion is bent toward the first end face of the pole piece assembly, and along the width direction of the first pole piece, the first bending portion is located on one side of the pole piece assembly, and the first bending portion is connected to the first shell; the second pole ear includes a second connecting portion and a second bending portion, the second connecting portion is connected to the second region, the second bending portion is bent toward the second end face of the pole piece assembly, the second end face and the first end face are arranged opposite to each other along the width direction of the first pole piece, and along the width direction of the first pole piece, the second bending portion is located on the side of the pole piece assembly away from the first bending portion.

4. The electrochemical device according to claim 3, characterized in that The electrochemical device satisfies at least one of the following conditions: (1) The first bending portion includes a third region connected to the first shell portion, and the angle between a ray from the center of the third region to the center of the first region and a ray from the center of the third region to the first starting end is η, satisfying η≤45°; (2) The second shell portion includes a fourth region connected to the second bending portion, and an angle δ between a ray from the center of the fourth region to the center of the second region and a ray from the center of the fourth region to the second starting end satisfies δ≤45°; (3) The first shell portion includes a top wall, a bottom wall and a side wall, and the second shell portion includes a pole. The top wall is provided with a through hole, and the pole is provided in the through hole; (4) The first connecting member is disposed on the first end surface side; (5) The second connection member is provided on the second end surface side.

5. The electrochemical device according to claim 1, characterized in that Along the winding direction of the pole piece assembly from inside to outside, the winding tail section of the first current collector includes a blank section that exceeds the first region and has no first active layer on the surface, and the blank section covers the winding tail section of the second current collector.

6. The electrochemical device according to claim 1, characterized in that The electrochemical device satisfies at least one of the following conditions: (1) 30°≤γ≤450°; (2) 15°≤α1≤210°; (3) 15°≤α2≤210°; (4) The winding length of the first region beyond the second region is less than one turn.

7. The electrochemical device according to claim 1, characterized in that The first pole piece is a negative pole piece, and the second pole piece is a positive pole piece; wherein, The winding start section of the first active layer exceeds the winding start section of the second active layer in the opposite direction of the winding direction of the pole piece assembly from inside to outside, and / or The winding tail section of the first active layer exceeds the winding tail section of the second active layer along the winding direction of the pole piece assembly from inside to outside.

8. The electrochemical device according to any one of claims 1 to 7, characterized in that: At least one of the following conditions is met: (a) the pole piece assembly further comprises a first diaphragm, the first diaphragm is arranged between the first pole piece and the second pole piece, and along the winding direction of the pole piece assembly from inside to outside, the winding end of the first diaphragm exceeds the first pole piece; (b) The pole piece assembly further includes a second diaphragm, which is disposed between the first pole piece and the second pole piece, and along the winding direction of the pole piece assembly from inside to outside, the winding end of the second diaphragm exceeds the second pole piece.

9. The electrochemical device according to any one of claims 1 to 7, characterized in that: The electrochemical device further includes an insulating member disposed between the housing and the pole piece assembly.

10. An electrical device, characterized in that: An electrochemical device comprising any one of claims 1 to 9.

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