Electrochemical apparatus and electric device

Abstract

The present application discloses an electrochemical apparatus and an electric device. The electrochemical apparatus comprises a first housing part and a second housing part having different polarities, an electrode assembly, and a first connecting member. The electrode assembly comprises an electrode sheet assembly, a first tab, and a second tab. A first electrode sheet of the electrode sheet assembly is located on a winding inner side relative to a second electrode sheet, the first tab is connected to a first area of the first electrode sheet, and the first tab comprises a second area connected to the first housing part. The second tab is connected to a third area of the second electrode sheet. The first connecting member is connected to the first housing part and comprises a fourth area used for being connected to an electric device. The winding length of the first area beyond the third area is less than one turn. The included angle between the first area and the third area relative to a winding center is θ, which satisfies: 45°≤θ≤135°. The included angle between the first area and the fourth area relative to the third area is α, which satisfies: -60°≤α≤45°. The electrochemical apparatus of the present application is beneficial to weakening axial magnetic fields on end faces, thereby reducing the interference with the electric 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] For batteries with a spiral involute structure, a strong axial magnetic field is generated at the end faces of the wound structure due to its special spiral involute structure. This can cause significant interference to electrical devices such as Bluetooth headsets, affecting their normal operation.

[0003] Summary of the Invention

[0004] In view of this, the present application provides an electrochemical device that is beneficial for reducing the axial magnetic field at the end face of the winding structure, 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, an electrode assembly, and a first connector. The electrode assembly is housed in the housing, and the first connector is located outside the housing. The housing comprises a first shell portion and a second shell portion with different polarities. The electrode assembly comprises a pole piece assembly, a first tab, and a second tab. The pole piece assembly comprises a first pole piece and a second pole piece arranged in a wound manner. The first pole piece comprises a first current collector and a first active layer located on the surface of the first current collector. The second pole piece comprises 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 inner side of the winding of the pole piece assembly relative to the winding start section of the second active layer. The first tab comprises a first connecting portion and a first bending portion. The first connecting portion is connected to a first region of the winding end section of the first current collector. The first bending portion is bent toward a first end face of the pole piece assembly and is located on one side of the pole piece assembly along the width direction of the first pole piece. The first bending portion includes a second region connected to the first shell portion. The second pole lug includes a second connecting portion and a second bending portion. The second connecting portion is connected to the third region of the winding tail section of the second current collector. 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. 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. Along the winding direction of the pole piece assembly from the inside to the outside, the first region exceeds the third region, and the winding length of the first region exceeding the third region is less than one turn. The first connecting member is connected to the first shell and has a fourth region for connecting to an external load. Observed along the width direction of the first pole piece and 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 third region and the ray from the winding center to the center of the first region is θ, which satisfies the following: 45°≤θ≤135°. Observed along the width direction of the first pole piece, the angle α between the ray from the center of the second region to the center of the first region and the ray from the center of the second region to the center of the fourth region satisfies the following: -60°≤α≤45°. The angle α between the ray from the center of the second region to the center of the first region and the ray from the center of the second region to the center of the fourth region along the winding direction of the pole piece assembly from the inside to the outside is positive; the angle α between the ray from the center of the second region to the center of the first region and the ray from the center of the second region to the center of the fourth region along the direction opposite to the winding direction of the pole piece assembly from the inside to the outside is negative.

[0006] Through research, the inventors of this application discovered that due to the unique spiral involute structure of a wound battery, the effective current path length of the first pole piece on the inner side of the winding is shorter than that of the second pole piece on the outer side of the winding, resulting in a strong axial magnetic field at both end faces of the winding. Furthermore, the current flowing through the bends of the tabs parallel to the end faces of the winding and the connectors located outside the housing also affect the axial magnetic field. This invention, on the one hand, extends the effective length of the first pole piece on the inner side of the winding, allowing the first region to extend beyond the third region, and ensuring that θ satisfies the following conditions: 45° ≤ θ ≤ 135°. When the electrode assembly discharges and generates current, the magnetic field generated by the portion of the first pole piece extending beyond the third region can at least partially offset the axial magnetic field generated by the spiral involute structure. On the other hand, by controlling the angle between the first tab and the first connector to satisfy the following conditions: -60° ≤ α ≤ 45°, the axial magnetic field generated by the current flowing through the first tab and the first connector further offsets the axial magnetic field generated by the spiral involute structure at the first end face, thereby significantly reducing the interference of the electrochemical device with electrical equipment.

[0007] In some embodiments, 60°≤θ≤120°. In this way, the magnetic field generated by the portion of the first pole piece extending beyond the third region can better offset the axial magnetic field generated by the spiral involute structure in the pole piece assembly, thereby further reducing the interference of the electrochemical device on the electrical equipment.

[0008] In some embodiments, -25°≤α≤25°. Thus, the axial magnetic field generated by the current passing through the first electrode tab and the first connector can better offset the axial magnetic field generated by the spiral involute structure in the pole piece assembly, thereby further reducing the interference of the electrochemical device on the electrical equipment.

[0009] In some embodiments, 30°≤θ+α≤135°. Thus, the magnetic field generated by the portion of the first pole piece extending beyond the third region and the axial magnetic field generated by the current passing through the first pole lug and the first connector can better offset the axial magnetic field generated by the spiral involute structure in the pole piece assembly, thereby further reducing interference of the electrochemical device on electrical equipment.

[0010] In some embodiments, the first electrode is a negative electrode, and the second electrode is a positive electrode. In the direction opposite to the winding direction of the electrode assembly from the inside out, the first active layer's winding start section extends beyond the second active layer's winding start section. In some embodiments, in the winding direction of the electrode assembly from the inside out, the first active layer's winding end section extends beyond the second active layer's winding end section. This arrangement allows the negative active layer's end section to extend beyond the positive active layer in the winding direction of the electrode assembly, thereby reducing the risk of lithium plating and improving the safety of the electrochemical device.

[0011] In some embodiments, the first shell portion includes a top wall, a bottom wall and a side wall, the first bent portion is connected to the bottom wall, 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.

[0012] 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.

[0013] In some embodiments, the second bend includes a fifth region connected to the second shell. The electrochemical device further includes a second connector connected to the second shell and having a sixth region for connection to an external load. When viewed along the width of the first pole piece, the angle β between a ray from the center of the fifth region to the center of the third region and a ray from the center of the fifth region to the center of the sixth region satisfies the following conditions: -60° ≤ β ≤ 45°. The angle β between the ray from the center of the fifth region to the center of the third region and the ray from the center of the fifth region to the center of the sixth region, along the winding direction of the pole piece assembly from inside to outside, is positive; the angle β between the ray from the center of the fifth region to the center of the third region and the ray from the center of the fifth region to the center of the sixth region, in the opposite direction of the winding direction of the pole piece assembly, is negative. Thus, by ensuring that the angle between the second pole tab and the second connector satisfies the following conditions: -60° ≤ β ≤ 45°, the axial magnetic field generated by current passing through the second pole tab and the second connector further offsets the axial magnetic field generated by the spiral involute structure on the second end face, thereby further reducing interference with electrical equipment.

[0014] In some embodiments, the electrode assembly further includes a first diaphragm, which is disposed between the first electrode and the second electrode. The first diaphragm extends beyond the first electrode along the winding direction of the electrode assembly from the inside out. Thus, the first electrode's winding end is covered by the first diaphragm, which helps reduce the risk of direct contact between the first and second electrode sheets.

[0015] 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 end of the second electrode, thereby reducing the risk of direct contact between the second electrode and the first electrode or the housing.

[0016] 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.

[0017] In a second aspect, the present application further provides an electrical device comprising the electrochemical device according to any of the above embodiments. The electrochemical device according to the above embodiments has a reduced axial magnetic field, which reduces electromagnetic interference to the electrical device, thereby improving the reliability of the electrical device. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG1 is a schematic diagram of an electrical device provided in an embodiment of the present application.

[0019] FIG2 is a schematic structural diagram of an electrochemical device provided in one embodiment of the present application.

[0020] FIG3 is a cross-sectional view of the electrochemical device in FIG2 .

[0021] FIG4 is a schematic structural diagram of an electrode assembly provided in one embodiment of the present application.

[0022] FIG5 is a schematic diagram of the winding of a pole piece assembly provided in one embodiment of the present application.

[0023] FIG6 is a schematic structural diagram of an electrode assembly and a first connecting member provided in one embodiment of the present application.

[0024] FIG7 is a schematic diagram of the winding of a pole piece assembly provided in another embodiment of the present application.

[0025] FIG8 is a schematic structural diagram of an electrode assembly and a second connecting member provided in one embodiment of the present application.

[0026] Description of Main Component Symbols Electrochemical Device 100 Housing 10 First Shell 11 Top Wall 111 Through Hole 1111 Bottom Wall 112 Side Wall 113 Accommodating Space 11a Second Shell 12 Mounting Portion 121 Lead-Out Portion 122 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 First Active Layer 2112 Second Pole Plate 212 Second Current Collector 2121 Third Region 212a Second Active Layer 2122 First Separator 213 Second Separator 214 First Tab 22 First Connecting Portion 221 First Bend Portion 222 Second Region 222a Second Tab 23 Second Connecting Portion231 Second bend 232 Fifth region 232a First connector 30 Fourth region 31 Second connector 40 Sixth region 41 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

[0027] 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.

[0028] It should be noted that in this application, "region center" 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 made in the vertical direction from the starting point of the thin line. The plane shape is suspended again with an endpoint different from the first time, and another straight line is made 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 containing 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 "set on" another component, it can be directly set on the other component or there may be a central component at the same time. The terms "top", "bottom" and similar expressions used herein are for illustrative purposes only.

[0029] 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.

[0030] 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.

[0031] 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 this application is not limited to the sizes and thicknesses shown in the drawings. Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0032] 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.

[0033] An embodiment of the present application provides an electrical device 1000 , which includes an electrochemical device 100 .

[0034] 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 .

[0035] 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.

[0036] In some embodiments, referring to FIG. 2 and FIG. 3 , the electrochemical device 100 includes a housing 10 , an electrode assembly 20 , and a first connector 30 . The electrode assembly 20 is housed in the housing 10 , and the first connector 30 is located outside the housing 10 and connected to the housing 10 .

[0037] In some embodiments, referring to FIG. 2 and FIG. 3 , the housing 10 includes a first housing portion 11 and a second housing portion 12 , and the first housing portion 11 and the second housing portion 12 are insulated and connected.

[0038] 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.

[0039] 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 .

[0040] 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.

[0041] 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 .

[0042] In some embodiments, the seal 50 may be a sealant.

[0043] 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.

[0044] In some embodiments, referring to FIG. 3 , the electrode assembly 20 includes a pole piece assembly 21 , a first pole tab 22 , and a second pole tab 23 . The first pole tab 22 and the second pole tab 23 are both connected to the pole piece assembly 21 .

[0045] 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. As an 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.

[0046] Referring to Figure 5 , 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 comprising 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.

[0047] In some embodiments, referring to Figures 4 and 5 , 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. The winding start section of the first active layer 2112 is located on the inner side of the winding of the electrode piece assembly 21 relative to the winding start section of the second active layer 2122. The first electrode tab 22 includes a first connecting portion 221 and a first bend portion 222. The first connecting portion 221 is connected to the first region 211a of the winding end section of the first current collector 2111. It can be understood that the first region 211a is the region where the first current collector 2111 is connected to the first connecting portion 221. 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-shaped 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 bend portion 222 bends toward the first end face 21a of the pole piece assembly 21, and along the width direction X of the first pole piece 211, the first bend portion 222 is located on one side of the pole piece assembly 21. The first bend portion 222 is connected to the first shell 11, and the first bend portion 222 includes a second region 222a connected to the first shell 11. It can be understood that the second region 222a is the region where the first bend portion 222 is connected to the first shell portion 11, wherein the method for determining the center of the second region 222a is the same as the method for determining the center of the first region 211a, and will not be repeated here. The second pole lug 23 includes a second connecting portion 231 and a second bend portion 232, and the second connecting portion 231 is connected to the third region 212a of the winding tail section of the second current collector 2121. It can be understood that the third 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 third 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 bend portion 232 is bent toward the second end face 21b of the pole piece assembly 21, and along the width direction X of the first pole piece 211, the second bend portion 232 is located on the side of the pole piece assembly 21 away from the first bend portion 222.

[0048] Please continue to refer to Figure 5. Along the winding direction C from the inside to the outside of the pole piece assembly 21, the first area 211a exceeds the third area 212a, and the winding length of the first area 211a beyond the third area 212a is less than one circle. Observing along the width direction X of the first pole piece 211 and along the winding direction C from the inside to the outside of the pole piece assembly 21, the angle between the ray from the winding center D of the pole piece assembly 21 to the center of the third area 212a and the ray from the winding center D to the center of the first area 211a is θ, which satisfies: 45°≤θ≤135°. Please continue to refer to Figures 3 and 6. The first connector 30 is connected to the first shell 11. The first connector 30 has a fourth area 31 for connecting to an external load. The method for determining the center of the fourth area 31 is the same as the method for determining the center of the first area 211a, and will not be repeated here. The first pole piece 211 in the pole piece assembly 21 is electrically connected to the external load through the first pole lug 22, the first shell 11 and the first connector 30. Observing along the width direction X of the first pole piece 211, the angle α between the ray from the center of the second region 222a to the center of the first region 211a and the ray from the center of the second region 222a to the center of the fourth region 31 satisfies: -60°≤α≤45°.

[0049] Among them, along the winding direction C of the pole piece assembly 21 from the inside to the outside, the angle α of the ray from the center of the second area 222a to the center of the first area 211a to the ray from the center of the second area 222a to the center of the fourth area 31 is a positive value; along the direction opposite to the winding direction of the pole piece assembly 21 from the inside to the outside, the angle α of the ray from the center of the second area 222a to the center of the first area 211a to the center of the second area 222a to the center of the fourth area 31 is a negative value.

[0050] Through research, the inventors of this application discovered that due to the unique spiral involute structure of the wound battery, the effective current path length of the first pole piece 211 on the inner side of the winding is shorter than the effective current path of the second pole piece 212 on the outer side of the winding, thereby generating a strong axial magnetic field at both end faces of the winding body. Furthermore, the current flowing through the first bend 222 of the first tab 22, which is parallel to the end face of the winding structure, and the first connector 30 disposed outside the housing 10, also affect the axial magnetic field. 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 third region 212a, and θ satisfies: 45°≤θ≤135°. 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 third region 212a can at least partially offset the axial magnetic field generated by the spiral involute structure; on the other hand, by controlling the first pole ear 22 and the first connecting member 30 to satisfy: -60°≤α≤45°, the axial magnetic field generated by the current passing through the first pole ear 22 and the first connecting member 30 further offsets the axial magnetic field generated by the spiral involute structure on the first end face 21a, thereby greatly reducing the interference of the electrochemical device 100 on the electrical equipment 1000.

[0051] For example, θ may be 45°, 60°, 75°, 90°, 105°, 120°, 135°, or a range consisting of any two of the above. For example, α may be -60°, -45°, -30°, -25°, -10°, 0°, 10°, 25°, 35°, 45°, or a range consisting of any two of the above.

[0052] In some embodiments, 60°≤θ≤120°. Thus, the magnetic field generated by the portion of the first pole piece 211 extending beyond the third region 212a can better offset the axial magnetic field generated by the spiral involute structure in the pole piece assembly 21, thereby further reducing interference of the electrochemical device 100 with the electrical equipment 1000.

[0053] In some embodiments, -25°≤α≤25°. Thus, the axial magnetic field generated by the current passing through the first electrode tab 22 and the first connector 30 can better offset the axial magnetic field generated by the spiral involute structure in the pole piece assembly 21, thereby further reducing the interference of the electrochemical device 100 on the electrical equipment 1000.

[0054] In some embodiments, 30°≤θ+α≤135°. Thus, the magnetic field generated by the portion of the first pole piece 211 extending beyond the third region 212a, as well as the axial magnetic field generated by the current passing through the first pole tab 22 and the first connector 30, effectively offset the axial magnetic field generated by the spiral involute structure in the pole piece assembly 21, thereby further reducing the interference of the electrochemical device 100 with the electrical equipment 1000. For example, θ+α can be 30°, 45°, 60°, 75°, 90°, 105°, 120°, 135°, or a range consisting of any two of the foregoing.

[0055] In some embodiments, referring to Figures 3, 4, and 7, the first bend 222 of the first electrode tab 22 is connected to the bottom wall 112, and the second bend 232 of the second electrode tab 23 is connected to the mounting portion 121 of the electrode column. Along the winding direction C from the inside to the outside of the electrode assembly 21, the winding tail section of the first current collector 2111 includes a blank section that extends beyond the first region 211a and is not provided with the first active layer 2112 on its surface. This blank section covers the winding tail section of the second current collector 2121. This arrangement provides a blank section of the first current collector 2111 between the winding tail section of the second current collector 2121 and the first shell 11, which helps to enhance the isolation between the second current collector 2121 and the first shell 11, thereby helping to reduce the risk of short circuit caused by direct contact between the second current collector 2121 and the first shell 11.

[0056] In some embodiments, referring to Figures 5 and 7, the first electrode 211 is a negative electrode, the second electrode 212 is a positive electrode, and in the opposite direction of the winding direction C from the inside to the outside of the electrode assembly 21, the winding starting section of the first active layer 2112 exceeds the winding starting section of the second active layer 2122.

[0057] In some embodiments, referring to Figures 5 and 7 , along the winding direction C from the inside to the outside of the electrode assembly 21, the end of the first active layer 2112 extends beyond the end of the second active layer 2122. This arrangement allows the end of the negative electrode active layer to extend beyond the positive electrode active layer in the winding direction C of the electrode assembly 21, thereby reducing the risk of lithium plating and improving the safety of the electrochemical device 100.

[0058] In some embodiments, referring to Figures 5 and 7, the pole piece assembly 21 further includes a first diaphragm 213, 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 213 exceeds the first pole piece 211, so that the winding tail end of the first pole piece 211 is covered by the first diaphragm 213, which helps to reduce the risk of direct contact between the first pole piece 211 and the second pole piece 212.

[0059] In some embodiments, referring to Figures 5 and 7, the pole piece assembly 21 further includes a second diaphragm 214, 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 second diaphragm 214 exceeds the second pole piece 212, allowing the winding tail end of the second pole piece 212 to be covered by the second diaphragm 214, which helps to reduce the risk of direct contact between the second pole piece 212 and the first pole piece 211 or the shell 10.

[0060] In some embodiments, along the winding direction C from the inside to the outside of the pole piece assembly 21, the winding tail ends of the first diaphragm 213 and / or the second diaphragm 214 are fixed to the main body of the pole piece assembly 21 by adhesive tape, which helps to reduce the risk of curling of the winding tail ends of the first diaphragm 213 and / or the second diaphragm 214.

[0061] 5 and 7 , the second electrode piece 212 is located between the first diaphragm 213 and the second diaphragm 214 . The first electrode piece 211 is located between the first diaphragm 213 and the second diaphragm 214 .

[0062] In some embodiments, the first diaphragm 213 and the second diaphragm 214 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 .

[0063] In some embodiments, referring to FIG. 4 , the first bent portion 222 extends in a direction parallel to the first end surface 21 a .

[0064] 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.

[0065] In some embodiments, referring to Figures 3 and 4 , the second bent portion 232 is connected to the second shell portion 12, and the second bent portion 232 includes a fifth region 232a connected to the second shell portion 12. It is understood that the fifth region 232a is the region where the second bent portion 232 connects to the second shell portion 12. The method for determining the center of the fifth region 232a is the same as the method for determining the center of the first region 211a, and will not be repeated here.

[0066] In some embodiments, referring to FIG. 4 , the second bent portion 232 extends in a direction parallel to the second end surface 21 b .

[0067] In some embodiments, the second connection portion 231 and the second current collector 2121 can be connected by welding, bonding or pressing, and the second bending portion 232 and the second shell 12 can be connected by welding, bonding or pressing, which are not specifically limited here.

[0068] In some embodiments, referring to Figures 3 and 8 , the electrochemical device 100 further includes a second connector 40 connected to the second shell 12 and having a sixth region 41 for connection to an external load. The method for determining the center of the sixth region 41 is similar to the method for determining the center of the first region 211a and is not further described here. When viewed along the width direction X of the first electrode 211, the angle β between a ray from the center of the fifth region 232a to the center of the third region 212a and a ray from the center of the fifth region 232a to the center of the sixth region 41 satisfies the following: -60° ≤ β ≤ 45°. Among them, along the winding direction C from the inside to the outside of the pole piece assembly 21, the angle β from the ray from the center of the fifth area 232a to the center of the third area 212a to the ray from the center of the fifth area 232a to the center of the sixth area 41 is a positive value; along the opposite direction of the winding direction C from the inside to the outside of the pole piece assembly 21, the angle β from the ray from the center of the fifth area 232a to the center of the third area 212a to the center of the fifth area 232a to the center of the sixth area 41 is a negative value.

[0069] By setting the angle between the second pole ear 23 and the second connecting member 40 to satisfy: -60°≤β≤45°, the axial magnetic field generated by the current passing through the second pole ear 23 and the second connecting member 40 further offsets the axial magnetic field generated by the spiral involute structure on the second end face 21b, thereby further reducing interference to the electrical equipment 1000.

[0070] 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.

[0071] In order to verify the canceling effect of the magnetic field generated in the axial direction by the electrochemical device 100 of the present application, the following comparative tests were conducted:

[0072] For example, a Bluetooth headset assembled with a wound cylindrical steel-cased battery has a voice coil radius of 3.5 mm, and the negative terminal (bottom wall 112 of the housing 10) is located near the Bluetooth headset speaker. The current sound level of the Bluetooth headset was tested at different values ​​of α and θ. The test results are shown in Table 1 below.

[0073] Among them, by changing the welding position of the first pole tab 22 and the second pole tab 23, the value of the angle θ between the first pole tab 22 and the second pole tab 23 is changed, and by changing the connection direction of the first connecting member 30, the value of the angle α between the first connecting member 30 outside the shell 10 and the first pole tab 22 is changed.

[0074] Table 1: Current sound level (dB) of Bluetooth headsets at different α and θ

[0075] It should be noted that the smaller the sound, the lower the decibel, and 0dB is the smallest sound that can be heard by the human ear.

[0076] Please refer to Table 1 and Figure 5. When the angle θ satisfies: 45° ≤ θ ≤ 135°, and the angle α satisfies: -60° ≤ α ≤ 45°, the Bluetooth headset has a significantly reduced current noise level. This is because, on the one hand, by extending the effective length of the negative electrode pole piece located on the inner side of the winding, so that the first region extends beyond the third region, and θ satisfies: 45° ≤ θ ≤ 135°, when the electrode assembly discharges and generates current, the magnetic field generated by the portion of the negative electrode pole piece that extends beyond the third region can at least partially offset the axial magnetic field generated by the spiral involute structure. On the other hand, by controlling the angle between the first tab and the first connector to meet: -60° ≤ α ≤ 45°, the axial magnetic field generated by the current passing through the first tab and the first connector further offsets the axial magnetic field generated by the spiral involute structure at the negative end face, thereby significantly reducing the battery's interference with the Bluetooth headset.

[0077] Furthermore, when the angle θ satisfies the following conditions: 60° ≤ θ ≤ 120°, and the angle α satisfies the following conditions: -25° ≤ α ≤ 25°, the current noise level of the Bluetooth headset is lower. In this case, the magnetic field generated by the portion of the negative electrode extending beyond the third region and the axial magnetic field generated by the current passing through the first tab and the first connector better offset the axial magnetic field generated by the spiral involute structure in the pole piece assembly, thereby further reducing the interference of the battery on the Bluetooth headset.

[0078] 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: It comprises a shell, an electrode assembly and a first connecting member, wherein the electrode assembly is accommodated in the shell, and the first connecting member is located outside the shell; The shell comprises a first shell portion and a second shell portion having different polarities; The electrode assembly comprises a pole piece assembly, a first pole lug and a second pole lug; The pole piece assembly comprises a first pole piece and a second pole piece which are wound, 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 lug includes a first connecting portion and a first bending portion, the first connecting portion is connected to the first region of the winding tail section of the first current collector, the first bending portion is bent toward the first end surface of the pole piece assembly, 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 includes a second region connected to the first shell portion; The second pole lug includes a second connecting portion and a second bending portion, the second connecting portion is connected to the third region of the second current collector winding tail section, 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 a side of the pole piece assembly away from the first bending portion; Along the winding direction of the pole piece assembly from inside to outside, the first region exceeds the third region, and the winding length of the first region exceeding the third region is less than one turn; The first connecting member is connected to the first shell portion and has a fourth area for connecting to an external load; 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 third region and the ray from the winding center to the center of the first region is θ, which satisfies: 45°≤θ≤135°; Observing along the width direction of the first pole piece, the angle between the ray from the center of the second area to the center of the first area and the ray from the center of the second area to the center of the fourth area is α, which satisfies: -60°≤α≤45°; Among them, along the winding direction of the pole piece assembly from the inside to the outside, the value of the angle α from the ray from the center of the second area to the center of the first area to the ray from the center of the second area to the center of the fourth area is a positive value; along the direction opposite to the winding direction of the pole piece assembly from the inside to the outside, the value of the angle α from the ray from the center of the second area to the center of the first area to the ray from the center of the second area to the center of the fourth area is a negative value.

2. The electrochemical device according to claim 1, characterized in that At least one of the following conditions is satisfied: (1) 60°≤θ≤120°; (2) -25°≤α≤25°.

3. The electrochemical device according to claim 1, characterized in that 30°≤θ+α≤135°.

4. 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, satisfying at least one of the following conditions: (1) In the opposite direction of the winding direction of the pole piece assembly from inside to outside, the winding start section of the first active layer exceeds the winding start section of the second active layer; (2) Along the winding direction of the pole piece assembly from inside to outside, the winding tail section of the first active layer exceeds the winding tail section of the second active layer.

5. The electrochemical device according to claim 1, characterized in that The first shell portion includes a top wall, a bottom wall and a side wall, the first bending portion is connected to the bottom wall, the second shell portion includes a pole, the top wall is provided with a through hole, and the pole is arranged in the through hole.

6. The electrochemical device according to claim 5, 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.

7. The electrochemical device according to claim 1, characterized in that The second bending portion includes a fifth region connected to the second shell portion; the electrochemical device further includes a second connector, the second connector is connected to the second shell portion and has a sixth region for connecting to an external load; Observing along the width direction of the first pole piece, the angle β between the ray from the center of the fifth region to the center of the third region and the ray from the center of the fifth region to the center of the sixth region satisfies: -60°≤β≤45°; Among them, along the winding direction of the pole piece assembly from the inside to the outside, the angle β of the ray from the center of the fifth area to the center of the third area to the ray from the center of the fifth area to the center of the sixth area is a positive value; along the opposite direction of the winding direction of the pole piece assembly from the inside to the outside, the angle β of the ray from the center of the fifth area to the center of the third area to the ray from the center of the fifth area to the center of the sixth area is a negative value.

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: (1) The pole piece assembly further includes a first diaphragm, the first diaphragm 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 tail section of the first diaphragm exceeds the first pole piece; (2) 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 second diaphragm The winding tail section 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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