CN114204221A

CN114204221A - Electrochemical device, battery module and electronic device

Info

Publication number: CN114204221A
Application number: CN202111460367.8A
Authority: CN
Inventors: 李勇; 曾巧
Original assignee: Ningde Amperex Technology Ltd
Current assignee: Ningde Amperex Technology Ltd
Priority date: 2021-12-02
Filing date: 2021-12-02
Publication date: 2022-03-18

Abstract

The present application relates to an electrochemical device including a case, an electrode assembly, a first tab, and a first conductive member. The shell is provided with a first cavity and a first hole, the first hole is communicated with the first cavity, the electrode assembly is arranged in the first cavity, the first end of the first tab is electrically connected with the electrode assembly, the first conductive piece is arranged in the first hole, the first conductive piece is provided with a second cavity, the second end of the first tab is arranged in the second cavity, and the second end of the first tab is electrically connected with the first conductive piece. The application also relates to a battery module and an electronic device. By the mode, the electrochemical device can save the internal space of the electrochemical device and improve the energy density.

Description

Electrochemical device, battery module and electronic device

Technical Field

The embodiment of the application relates to the technical field of energy storage, in particular to an electrochemical device, a battery module and an electronic device.

Background

An electrochemical device is a device that converts external energy into electrical energy and stores the electrical energy in the device to supply power to an external electronic device (e.g., a portable electronic device) at a desired time. The electrochemical device is widely applied to daily life, and provides great convenience and richness for the daily life of people.

In the course of implementing the present application, the inventors of the present application found that there is still a great need in the field of energy storage technology to improve the energy density of electrochemical devices.

Disclosure of Invention

In view of the above, embodiments of the present application provide an electrochemical device, a battery module, and an electronic device, which can improve the energy density of the electrochemical device.

According to an aspect of an embodiment of the present application, there is provided an electrochemical device including: includes a case, an electrode assembly, and a first tab and a first conductive member. The shell is provided with a first cavity and a first hole, the first hole is communicated with the first cavity, the electrode assembly is arranged in the first cavity, the first end of the first tab is electrically connected with the electrode assembly, in addition, the first conductive piece is arranged in the first hole, the first conductive piece is provided with a second cavity, the second end of the first tab is arranged in the second cavity, and the second end of the first tab is electrically connected with the first conductive piece. The second end of the first tab is accommodated and fixed by the second cavity of the first conductive piece, so that the occupation of the internal space of the electrochemical device is reduced.

In an alternative mode, the first conductive member is provided with a first protrusion toward the second cavity, and the second end of the first tab is fixedly connected to the first protrusion. The first protruding part is used for increasing the connection area between the first conductive piece and the first tab.

In an alternative mode, the cross section of the second cavity includes a first end and a second end, the first end is located at one end far away from the electrode assembly, the second end is located at the other end close to the electrode assembly, and the area of the cross section close to the first end is smaller than that of the cross section close to the second end, wherein the cross section of the second cavity is a section of the second cavity along a second direction.

In an alternative form, the cross-sectional area of the second cavity increases progressively along the first direction. The first direction is a direction from the second end of the first conductive piece to the first end of the first conductive piece, and the second direction is perpendicular to the first direction.

In an alternative mode, the cross section of the first conductive member includes a third end and a fourth end, the third end is located at one end far away from the electrode assembly, the fourth end is located at the other end close to the electrode assembly, an area enclosed by an outer contour of the cross section close to the third end is smaller than an area enclosed by an outer contour of the cross section close to the fourth end, and the cross section of the first conductive member is a section of the first conductive member along the second direction.

In an alternative mode, the area enclosed by the outer contour of the cross section of the first conductive member is gradually increased along the first direction. The cross section of the first conductive piece is a section of the first conductive piece along a second direction, the first direction is a direction from the second end of the first conductive piece to the first end of the first conductive piece, and the second direction is perpendicular to the first direction. The area enclosed by the outer contour of the cross section of the first conductive piece is gradually increased, so that the first conductive piece and the first cover body are conveniently connected and sealed.

In an alternative form, the first tab is provided with at least one first recess, the at least one first recess forming a first channel. The first channel is convenient for electrolyte to flow into the first cavity, and the first pole lug can be arranged in the second cavity conveniently.

In an alternative form, the first tab is provided with at least one second recess forming a second channel, wherein the direction in which the first channel extends and the direction in which the second channel extends have a predetermined angle. The second channel is communicated with the first channel, so that electrolyte can conveniently flow into the first cavity, and the first tab can be conveniently arranged in the second cavity.

In an alternative mode, the electrode assembly includes a first pole piece including a first current collector, and one end of the first current collector extends to form a first tab.

In an alternative, the first tab includes a plurality of first sub-tabs connected to the first current collector.

In an alternative manner, the ratio of the length of the first tab to the length of the first current collector along the extension direction of the first current collector ranges from 0.7 to 1.0.

In an alternative mode, the electrochemical device further includes a first structural member disposed between an outer wall surface of the first conductive member and an inner wall surface of the first hole. The first structural member may seal a connection between the first conductive member and the housing.

In an alternative form, the first structural member comprises an insulating material.

In an alternative mode, the first conductive member protrudes from the outer surface of the shell.

In an optional manner, the electrochemical device further includes a second tab and a second conductive member, the housing is provided with a second hole communicating with the cavity, the second conductive member is mounted in the second hole, and the second conductive member is provided with a third cavity. The first end of the second tab is connected to the electrode assembly, the second end of the second tab is disposed in the third cavity, and the second end of the second tab is electrically connected to the second conductive member. And the third cavity of the second conductive piece is used for accommodating and fixing the second end of the second tab, so that the occupation of the internal space of the electrochemical device is reduced.

In an alternative form, the electrochemical device further includes a second structural member disposed between an outer wall of the second conductive member and an inner wall surface of the second hole. The second structural member may seal a junction between the second conductive member and the housing.

In an optional mode, the housing includes a casing, a first cover and a second cover, the first cover and the second cover are respectively disposed at two ends of the casing, the first cover and the second cover jointly enclose a first cavity, the first hole is disposed on the first cover, and the second hole is disposed on the second cover.

In an alternative mode, the first conductive member is connected to a first cover body, and the first cover body is insulated from the housing.

In an alternative form, the housing is cylindrical or square.

According to another aspect of embodiments of the present application, there is provided a battery module including the electrochemical device as described above.

According to another aspect of the embodiments of the present application, there is provided an electronic device including the battery module as described above.

The beneficial effect of this application includes: different from the prior art, the embodiment of the present application provides a case, an electrode assembly, a first tab, and a first conductive member. The shell is provided with a first cavity and a first hole, the first hole is communicated with the first cavity, the electrode assembly is arranged in the first cavity, the first conductive piece is arranged in the first hole, the first conductive piece is provided with a second cavity, the first end of the first lug is electrically connected with the electrode assembly, the second end of the first lug is arranged in the second cavity, and the second end of the first lug is electrically connected with the first conductive piece.

Drawings

One or more embodiments are illustrated by way of example in the accompanying drawings, which correspond to the figures in which like reference numerals refer to similar elements and which are not to scale unless otherwise specified.

FIG. 1 is a schematic view of the overall structure of an electrochemical device according to an embodiment of the present invention;

FIG. 2 is a sectional view taken along line A-A of FIG. 1;

FIG. 3 is an exploded view of a portion of the structure of the cross-sectional view of FIG. 2;

FIG. 4 is a schematic view of the overall structure of an embodiment of the electrochemical device of the present application;

FIG. 5 is a cross-sectional view taken at B-B of FIG. 4;

FIG. 6 is a schematic side view of an electrode assembly according to an embodiment of an electrochemical device of the present application;

FIG. 7 is a schematic view showing the development of a first electrode sheet of an electrochemical device according to an embodiment of the present invention;

FIG. 8 is a schematic view of a first pole piece of another embodiment of an electrochemical device of the present application;

fig. 9 is a schematic vertical sectional view of a first conductive member of an electrochemical device according to an embodiment of the present application;

fig. 10 is a schematic vertical sectional view of a first conductive member of another embodiment of an electrochemical device of the present application;

fig. 11 is a schematic vertical sectional view of a first conductive member of another embodiment of an electrochemical device of the present application;

fig. 12 is a schematic vertical sectional view of a first conductive member of another embodiment of an electrochemical device of the present application;

fig. 13 is a schematic cross-sectional view of a first conductive member of an electrochemical device according to an embodiment of the present application;

fig. 14 is a schematic cross-sectional view of a first conductive member of another embodiment of an electrochemical device of the present application;

fig. 15 is a schematic cross-sectional view of a first conductive member of another embodiment of an electrochemical device of the present application;

fig. 16 is a schematic cross-sectional view of a first conductive member of another embodiment of an electrochemical device of the present application;

FIG. 17 is a schematic view of a first pole piece deployed in accordance with an embodiment of the electrochemical device of the present application;

FIG. 18 is a schematic vertical cross-sectional view of another embodiment of an electrochemical device of the present application;

fig. 19 is a cross-sectional view of the first tab of fig. 18 taken at section C-C;

FIG. 20 is a schematic view of a first pole piece deployed from another embodiment of an electrochemical device of the present application;

fig. 21 is a schematic cross-sectional view of a first tab of another embodiment of an electrochemical device of the present application;

FIG. 22 is a schematic vertical cross-sectional view of yet another embodiment of an electrochemical device of the present application;

FIG. 23 is an exploded schematic view of a vertical cross-sectional portion of a structure of yet another embodiment of an electrochemical device of the present application;

FIG. 24 is a schematic vertical cross-sectional view of another embodiment of an electrochemical device of the present application;

FIG. 25 is a schematic view showing the overall structure of an electrode assembly according to an embodiment of the electrochemical device of the present application;

fig. 26 is a schematic view showing the overall structure of an electrode assembly according to another embodiment of an electrochemical device of the present application.

Detailed Description

In order to facilitate an understanding of the present application, the present application is described in more detail below with reference to the accompanying drawings and specific embodiments. It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may be present. The terms "vertical," "horizontal," "left," "right," "inner," "outer," and the like as used herein are for descriptive purposes only.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

To better explain the structure of the electrochemical device, the structure of the electrochemical device will be described with reference to X, Y, Z coordinate axes, wherein X, Y, Z coordinate axes are perpendicular to each other, the first direction is the positive direction of the X-axis, the second direction is the positive direction of the Y-axis, and the third direction is the positive direction of the Z-axis.

Referring to fig. 1 and 2, an electrochemical device 01 includes a case 10, an electrode assembly 20, a first tab 30, a first conductive member 50, and a first structural member 70. The electrode assembly 20 is disposed in the case 10, one end of the first tab 30 is electrically connected to the electrode assembly 20, the other end of the first tab 30 is electrically connected to the first conductive member 50, the first conductive member 50 is disposed on the case 10, and the first conductive member 50 is partially disposed in the case 10, and the first junction member 70 is disposed at a junction of the case 10 and the first conductive member 50. The first conductive member 50 may be used to electrically connect external devices, thereby enabling the charging and discharging of the electrochemical device. Optionally, the first conductive member 50 includes a metal material, such as: copper, and the like.

Specifically, referring to fig. 3 together with the housing 10, the housing 10 is provided with a first cavity 10a and a first hole 10b, the first hole 10b is communicated with the first cavity 10a, the first cavity 10a is used for accommodating the electrode assembly 20, and the first hole 10b is used for installing the first conductive member 50. In this embodiment, the case 10 is at least partially a metal case, and the metal case is electrically connected to the electrode assembly 20; it is understood that in other embodiments of the present application, the housing 10 is a plastic-aluminum film.

With respect to the electrode assembly 20, as shown in fig. 3, the electrode assembly 20 is disposed in the first cavity 10a, the electrode assembly 20 includes a first pole piece 201, a second pole piece 202, and a separator 203 disposed between the first pole piece 201 and the second pole piece 202, the first pole piece 210 and the second pole piece 220 have opposite polarities, one of the two is a positive pole piece, and the other is a negative pole piece. It is understood that the number of the first pole piece 201 and the second pole piece 202 is not limited, and can be adjusted adaptively according to the actual situation. The electrode assembly 20 may be a wound structure or a laminated structure, as shown in fig. 4 and 5, in which the wound structure electrode assembly includes a first pole piece 201 including a first current collector having at least one tab extending from one side thereof, a second pole piece 202 including a first active material layer disposed on the first current collector, and a separator 203 disposed therebetween. As shown in fig. 6, for the lamination stack electrode assembly including a plurality of first pole pieces 201, a plurality of second pole pieces 202, and a plurality of separators 203 disposed between the first pole pieces 201 and the second pole pieces 202, the first pole pieces 201 and the second pole pieces 202 are alternately stacked, and in some embodiments, each pole piece protrudes through a tab. Different structural types of the electrode assembly 20 are applicable to the present case, and are not particularly limited herein.

In some embodiments, as shown in fig. 7, the first pole piece 201 is unfolded along the third direction Z, the first pole piece 201 includes a first current collector 2011, one end of the first current collector 2011 extends toward a direction opposite to the first direction to form a first tab 30, and the first tab 30 and the first current collector 2011 are integrally formed. Optionally, along the extending direction of the first current collector 2011, the range of the ratio of the length D of the first tab 30 to the length H of the first current collector 2011 is 0.7 to 1.0, and it can be understood that, within the range of the ratio, the first tab 30 is easier to be disposed in the first conductive piece 50, and on the other hand, the larger the size of the first tab 30 along the extending direction of the first current collector 2011 is, the stronger the overcurrent capacity is, the better the rate performance is, and the better the heat dissipation performance is. As for the first conductive member 50, as shown in fig. 2 and 3, the first conductive member 50 is disposed in the first hole 10b, wherein the first conductive member 50 is used to connect with the first tab 30 and serve as an electrode of the electrochemical device. It should be noted that: the polarity of the first conductive member 50 is not particularly limited, and the polarity thereof is related to the polarity of the connected tab.

In some embodiments, the first conductive member 50 is provided with a second cavity 50a, and the second cavity 50a is used for receiving one end of the first tab 30. It is understood that, as shown in fig. 9 and 10, the shape of the second cavity 50a can be set according to actual needs, and the shape of the second cavity 50a can be rectangular, trapezoidal, etc.

In some embodiments, as shown in fig. 10, the cross-section of the second cavity includes a first end 50aa located at one end far away from the electrode assembly 20 and a second end 50ab located at the other end close to the electrode assembly 20, and the area of the cross-section close to the first end is smaller than that of the cross-section close to the second end, wherein the cross-section of the second cavity 50a is a section of the second cavity 50a along the second direction Y.

In some embodiments, the second cavity 50a has a cross-sectional area that gradually increases along the first direction X, as shown in fig. 10, such that the second cavity 50a facilitates receiving one end of the first tab 30. It is understood that the area of the cross section of the second cavity 50a gradually increases along the first direction X, and the shape of the cross section (vertical section) of the second cavity 50a along the first direction X may be trapezoidal.

In some embodiments, as shown in fig. 11, the cross section of the first conductive member 50 includes a third end 50b and a fourth end 50c, the third end is located at one end far away from the electrode assembly 20, the fourth end is located at the other end close to the electrode assembly 20, and an area enclosed by an outer contour of the cross section close to the third end is smaller than an area enclosed by an outer contour of the cross section close to the fourth end, wherein the cross section of the first conductive member 50 is a cross section of the first conductive member 50 along the second direction Y.

In some embodiments, along the first direction X, as shown in fig. 11, the area enclosed by the outer contour of the cross section of the first conductive member 50 is gradually increased, so that the first conductive member 50 and the first cover 102 are sealed. It is understood that the connection manner between the first conductive member 50 and the first cover 102 may be, but is not limited to, welding, screwing, and the like, as shown in fig. 12, and the overall outer contour of the first conductive member 50 may be a convex shape, and the like.

In some embodiments, as shown in fig. 13-16, the shape of the cross-section (cross-section) of the second cavity 50a along the second direction Y may be circular, rectangular, etc.

It should be noted that: the first direction X is a direction from the second end of the first conductive member 50 to the first end of the first conductive member 50, and the second direction Y is perpendicular to the first direction X.

In some embodiments, the first conductive member 50 is provided with a first protrusion 501 toward the second cavity 50a, the second end of the first tab 30 is fixedly connected to the first protrusion 501, and the first protrusion 501 is used for increasing the connection area with the first tab 30. It is understood that the connection manner between the first protrusion 501 and the first tab 30 may be, but is not limited to, a fixing manner such as welding.

As for the first tab 30, as shown in fig. 2, a first end of the first tab 30 is electrically connected to a pole piece of the electrode assembly 20, and a second end of the first tab 30 is disposed in the second cavity 50a and electrically connected to the first conductive member 50.

In some embodiments, as shown in fig. 17 to 19, in the case of the first tab 30 directly formed on the first current collector 2011 without die cutting, when the first tab 30 is disposed in the second cavity 50a and connected to the first conductive member 50, there is a case that the electrolyte is not easily infiltrated into the electrode assembly 20, and therefore, in some embodiments, the first tab 30 is provided with at least one first concave portion 30a, and the at least one first concave portion forms a first channel 301, and the first channel 301 facilitates the electrolyte to flow into the first cavity 10a and infiltrate the electrode assembly 20.

In some embodiments, as shown in fig. 20 to 21, the first tab 30 is provided with at least one second recess forming a second channel 302, the second channel 302 facilitating the electrolyte to flow into the first cavity 10a, wherein the direction in which the first channel 301 extends and the direction in which the second channel 302 extends have a predetermined included angle. The predetermined included angle can be set according to actual needs, and is not particularly limited, and the predetermined included angle can be 90 degrees and the like.

In some embodiments, the first tab 30 is formed by extending one end of the first current collector 2011, and the first tab 30 further includes a plurality of first sub-tabs 31 connected to the first current collector 2011.

As for the first structural member 70, as shown in fig. 2, the first structural member 70 is disposed between the outer wall surface of the first conductive member 50 and the inner wall surface of the first hole 10b, and the first structural member 70 can seal the connection between the first conductive member 50 and the housing 10.

It is to be understood that in the above-mentioned embodiment of the present application, the electrochemical device includes only the first tab 30, but in other embodiments of the present application, the electrochemical device may further include two or more tabs, wherein one of the two tabs connecting the first pole piece is defined as a first tab, and one of the two tabs connecting the second pole piece is defined as a second tab, and the specific structure of the electrochemical device including the first tab and the second tab in the embodiment of the present application will be described next.

As shown in fig. 22 and 23, the electrochemical device further includes a second tab 40, a second conductive member 60, and a second structural member 80. One end of the second tab 40 is electrically connected to the electrode assembly 20, the other end of the second tab 40 is electrically connected to a second conductive member 60, the second conductive member 60 is disposed on the case 10, and the second conductive member 60 is partially disposed in the case 10, and the second structural member 80 is disposed at a junction of the case 10 and the second conductive member 60.

In some embodiments, as shown in fig. 24, the housing 10 includes a casing 101, a first cover 102 and a second cover 103, the first cover 102 and the second cover 103 are respectively disposed at two ends of the casing 101, the first cover 102 and the second cover 103 together enclose a first cavity 10a, a first hole 10b is disposed in the first cover 102, a second hole 10c is disposed in the second cover 103, the first conductive member 50 is connected to the first cover 102, and the second conductive member 60 is connected to the second cover 103. Optionally, the first cover 102 is insulated from the housing 101. In some embodiments, the housing 10 is cylindrical or square.

In some embodiments, as shown in fig. 24, the first structural member 70 is disposed at the connection between the first cover 102 and the housing 101, and the first structural member 70 can perform a sealing function. Optionally, the first structural member 70 comprises an insulating material.

In some embodiments, the housing 10 is further provided with a second hole 10c, the second hole 10c is communicated with the first cavity 10a, and the second hole 10c is used for installing the second conductive member 60.

As for the second tab 40, as shown in fig. 22, a first end of the second tab 40 is electrically connected to another pole piece of the electrode assembly 20, and a second end of the second tab 40 is disposed in the third cavity 60a and electrically connected to the second conductive member 60.

It should be noted that: the positions of the first and

second tabs

30 and 40 are not particularly limited, and the positions of the first and

second tabs

30 and 40 may be on the same side as shown in fig. 25, or the positions of the first and

second tabs

30 and 40 may be on the opposite side as shown in fig. 26.

In some embodiments, a first end of the second tab 40 is connected to the electrode assembly 20, a second end of the second tab 40 is connected to the case 10, and a portion of the case 10 connected to the second tab 40 is made of a metal material.

As for the second conductive member 60, as shown in fig. 22 and 23, the second conductive member 60 is disposed in the second hole 10c, and the second conductive member 60 is used for connecting with the second tab 40 and serving as another electrode of the electrochemical device. It should be noted that: the polarities of the first and second

conductive members

50 and 60 are not particularly limited as long as the opposite polarities between the first and second

conductive members

50 and 60 are satisfied, which are related to the polarities of the connected tabs.

In some embodiments, the second conductive member 60 is provided with a third cavity 60a, and the third cavity 60a is used for receiving one end of the second tab 40.

The specific structure and function of the second conductive member 60 can be seen with reference to the first conductive member 50.

In some embodiments, the cross-section of the third cavity includes a fifth end and a sixth end, the fifth end is located at one end away from the electrode assembly, the sixth end is located at the other end close to the electrode assembly, and the area of the cross-section close to the fifth end is smaller than the area of the cross-section close to the sixth end.

In some embodiments, the area of the cross section of the third cavity 60a is gradually increased along the direction opposite to the first direction X, so that the third cavity 60a is configured to receive one end of the second tab 40, wherein the cross section of the third cavity 60a is the section of the third cavity 60a along the second direction Y. It is understood that the area of the cross section of the third cavity 60a gradually increases in the direction opposite to the first direction X, and the shape of the cross section (vertical section) of the second cavity 50a in the direction opposite to the first direction X may be trapezoidal.

In some embodiments, the shape of the cross-section (cross-section) of the third cavity 60a along the second direction Y may be circular, rectangular, etc.

In some embodiments, the cross section of the second conductive member includes a seventh end and an eighth end, the seventh end is located at one end far away from the electrode assembly, the eighth end is located at the other end close to the electrode assembly, and an area enclosed by outer contours of the cross section close to the seventh end is smaller than an area enclosed by outer contours of the cross section close to the eighth end.

In some embodiments, the area enclosed by the outer contour of the cross section of the second conductive member 60 is gradually increased along the direction opposite to the first direction X, wherein the cross section of the second conductive member 60 is the cross section of the second conductive member 60 along the second direction Y, which is configured to facilitate the connection and sealing between the second conductive member 60 and the second cover 103. It is understood that the connection manner between the second conductive member 60 and the second cover 103 may be, but is not limited to, welding, etc., and the overall outer contour of the second conductive member 60 may be a trapezoid, a convex shape, etc.

In some embodiments, the second conductive member 60 is provided with a second protrusion toward the third cavity 60a, and the second end of the second tab 40 is fixedly connected to the second protrusion, and the second protrusion is used for increasing the connection area with the second tab 40. It is understood that the connection between the second protrusion and the second tab 40 can be, but is not limited to, a fixed manner such as welding.

As shown in fig. 22, the second structural member 80 is disposed between the outer wall surface of the second conductive member 60 and the inner wall surface of the second hole 10 c. The second structure 80 may seal the connection between the second conductive member 60 and the housing 10.

In some embodiments, the second structural member 80 is disposed at a connection point of the second cover 103 and the housing 101, and the second structural member 80 can perform a sealing function. Optionally, the second structural member 80 comprises an insulating material.

In the embodiment of the present application, by providing the case 10, the electrode assembly 20, the first tab 30, and the first conductive member 50, the case 10 is provided with the first cavity 10a and the first hole 10b, the first hole 10b communicates with the first cavity 10a, the electrode assembly 20 is disposed in the first cavity 10a, the first conductive member 50 is disposed in the first hole 10b, the first conductive member 50 is provided with the second cavity 50a, the first end of the first tab 30 is electrically connected to the electrode assembly 20, the second end of the first tab 30 is disposed in the second cavity 50a, and the second end of the first tab 30 is electrically connected to the first conductive member 50, such that the second end of the first tab 30 is disposed in the second cavity 50a and electrically connected to the first conductive member 50, an internal space of the electrochemical device is saved, and an influence on an energy density of the electrochemical device is reduced.

Embodiments of the present disclosure also provide an embodiment of a battery module, where the battery module includes the electrochemical device described above, and the functions and structures of the electrochemical device may refer to the above embodiments, and are not described in detail here.

The embodiment of the present application further provides an example of an electronic device, where the electronic device includes the battery module, and the functions and the structure of the battery module can refer to the above embodiment, which is not described in detail herein. It is understood that the electronic device may be an energy storage product, a mobile phone, a tablet, a drone, a single wheel or two or more wheels of an electric vehicle, or an electric cleaning tool, etc.

It should be noted that the description of the present application and the accompanying drawings set forth preferred embodiments of the present application, however, the present application may be embodied in many different forms and is not limited to the embodiments described in the present application, which are not intended as additional limitations to the present application, but are provided for the purpose of providing a more thorough understanding of the present disclosure. Moreover, the above-mentioned technical features are combined with each other to form various embodiments which are not listed above, and all the embodiments are regarded as the scope described in the present specification; further, modifications and variations may occur to those skilled in the art in light of the foregoing description, and it is intended to cover all such modifications and variations as fall within the scope of the appended claims.

Claims

1. An electrochemical device comprising a housing, an electrode assembly, and a first tab, the housing having a first cavity and a first aperture, the first aperture in communication with the first cavity, the electrode assembly disposed within the first cavity, the first tab having a first end electrically connected to the electrode assembly, the electrochemical device comprising a first electrode and a second electrode,

the electrochemical device further comprises a first conductive piece, the first conductive piece is arranged in the first hole, the first conductive piece is provided with a second cavity, the second end of the first tab is arranged in the second cavity, and the second end of the first tab is electrically connected with the first conductive piece.

2. The electrochemical device according to claim 1,

the first conductive piece is provided with a first convex part towards the second cavity, and the second end of the first tab is fixedly connected to the first convex part.

3. The electrochemical device according to claim 1,

the cross section of the second cavity comprises a first end and a second end, the first end is located at one end far away from the electrode assembly, the second end is located at the other end close to the electrode assembly, the area of the cross section close to the first end is smaller than that of the cross section close to the second end, and the cross section of the second cavity is a section of the second cavity along a second direction.

4. The electrochemical device according to claim 3,

along a first direction, the area of the cross section of the second cavity is gradually increased, the first direction is a direction from the second end of the first conductive piece to the first end of the first conductive piece, and the second direction is perpendicular to the first direction.

5. The electrochemical device according to claim 1,

the cross section of the first conductive piece comprises a third end and a fourth end, the third end is located at one end far away from the electrode assembly, the fourth end is located at the other end close to the electrode assembly, the area enclosed by the outer contour of the cross section close to the third end is smaller than the area enclosed by the outer contour of the cross section close to the fourth end, and the cross section of the first conductive piece is the cross section of the first conductive piece along the second direction.

6. The electrochemical device according to claim 5,

along a first direction, an area surrounded by an outer contour of a cross section of the first conductive member is gradually increased, wherein the first direction is a direction from a second end of the first conductive member to a first end of the first conductive member, and the second direction is perpendicular to the first direction.

7. The electrochemical device of claim 1 wherein said first tab is provided with at least one first recess, said at least one first recess forming a first channel.

8. The electrochemical device as claimed in claim 7, wherein the first tab is further provided with at least one second recess forming a second channel, wherein a direction in which the first channel extends and a direction in which the second channel extends have a predetermined included angle.

9. The electrochemical device of claim 1, wherein said electrode assembly includes a first pole piece, said first pole piece including a first current collector, one end of said first current collector extending to form said first tab.

10. The electrochemical device of claim 9, wherein the first tab comprises a plurality of first sub-tabs connected to the first current collector.

11. The electrochemical device according to claim 9, wherein a ratio of the length of the first tab to the length of the first current collector along the extending direction of the first current collector ranges from 0.7 to 1.0.

12. The electrochemical device according to claim 1, further comprising a first structural member disposed between an outer wall surface of the first conductive member and an inner wall surface of the first hole.

13. The electrochemical device of claim 12, wherein the first structural member comprises an insulating material.

14. The electrochemical device of claim 1, wherein said first conductive member protrudes from an outer surface of said housing.

15. The electrochemical device of claim 1 further comprising a second tab, a first end of said second tab being attached to said electrode assembly and a second end of said second tab being attached to said housing.

16. The electrochemical device of claim 1, further comprising a second tab and a second conductive member, wherein the housing is provided with a second hole communicating with the cavity, the second conductive member is mounted to the second hole, and the second conductive member is provided with a third cavity;

the first end of the second tab is connected to the electrode assembly, the second end of the second tab is disposed in the third cavity, and the second end of the second tab is electrically connected to the second conductive member.

17. The electrochemical device of claim 16, further comprising a second structural member disposed between an outer wall of the second electrically conductive member and an inner wall surface of the second bore.

18. The electrochemical device according to claim 16, wherein the housing comprises a casing, a first cover and a second cover, the first cover and the second cover are respectively disposed at two ends of the casing, the first cover and the second cover together enclose the first cavity, the first hole is disposed on the first cover, and the second hole is disposed on the second cover.

19. The electrochemical device according to claim 18,

the first conductive piece is connected with the first cover body, and the first cover body is insulated from the shell.

20. The electrochemical device of claim 1, wherein said housing is cylindrical or square.

21. A battery module comprising the electrochemical device according to claims 1 to 20.

22. An electronic device, characterized by comprising the battery module according to claim 21.