ELECTROCHEMICAL APPARATUS AND ELECTRIC DEVICE

Abstract

An electrochemical apparatus includes an electrode assembly, a packaging bag and a first connecting layer. The electrode assembly includes an adhesive layer. An outermost current collector of the electrode assembly includes a first bending portion, a second bending portion opposite to the first bending portion and a flat portion connected between the first bending portion and the second bending portion. The packaging bag is configured to accommodate at least a part of the electrode assembly. The first connecting layer is pasted to the first bending portion and to a part of an outer surface of the flat portion.

Claims

1. An electrochemical apparatus, comprising: an electrode assembly comprising a first current collector, a second current collector, a first tab, a second tab, and a second winding adhesive; the first current collector and the second current collector are stacked and wound into a flat wound structure; the first tab is connected to the first current collector and extends out of the flat wound structure along a first direction, and the second tab is connected to the second current collector and extends out of the flat wound structure along the first direction; the first tab and the second tab are located on the same side of the flat wound structure, the second winding adhesive and the first tab are located on opposite sides of the electrode assembly, and the second winding adhesive is arranged to wrap around an end of the flat wound structure; an outermost layer of the first current collector is located on the outermost layer of the flat wound structure, the outermost layer of the first current collector comprises a first bending portion and a second bending portion opposite to the first bending portion and a flat portion connecting the first bending portion and the second bending portion; a packaging bag to accommodate the flat wound structure; and a first connecting layer, comprising a first surface opposite to an inner surface of the packaging bag and a second surface opposite to the first surface, wherein the second surface of the first connecting layer is pasted to a part of an outer surface of the first bending portion and to a part of an outer surface of the flat portion; the first connecting layer is connected to the second winding adhesive, and an orthographic projection of the first connecting layer and an orthographic projection of the second winding adhesive in a thickness direction of the flat wound structure overlap; the first direction, and the thickness direction of the flat wound structure are perpendicular to each other.

2. The electrochemical apparatus according to claim 1, wherein the electrode assembly comprises an adhesive layer, and the adhesive layer is pasted to a part of a surface of the flat portion; the orthographic projection of the first connecting layer and an orthographic projection of the adhesive layer in the thickness direction of the flat wound structure overlap.

3. The electrochemical apparatus according to claim 2, wherein the adhesive layer is pasted to a part of a surface of the flat portion facing toward a winding center of the electrode assembly.

4. The electrochemical apparatus according to claim 1, wherein the first connecting layer adheres the packaging bag to the electrode assembly.

5. The electrochemical apparatus according to claim 1, further comprising a second connecting layer, wherein the second connecting layer is pasted to a part of an outer surface of the second bending portion and to a part of the outer surface of the flat portion, the part of the outer surface of the flat portion is adjacent to the second bending portion.

6. The electrochemical apparatus according to claim 5, wherein the second connecting layer is connected to the second winding adhesive, the orthographic projection of the second connecting layer and the orthographic projection of the second winding adhesive in the thickness direction of the flat wound structure overlap.

7. The electrochemical apparatus according to claim 5, wherein the orthographic projection of the second connecting layer and the orthographic projection of the adhesive layer in the thickness direction of the flat wound structure overlap.

8. The electrochemical apparatus according to claim 5, wherein the electrode assembly has a third winding adhesive, the third winding adhesive and the first tab are located on opposite sides of the electrode assembly, and the second winding adhesive is arranged to wrap around an end of the flat wound structure; and the orthographic projection of the first connecting layer and the second winding adhesive in the thickness direction of the flat wound structure overlap;_ the orthographic projection of the second connecting layer and the third winding adhesive in the thickness direction of the flat wound structure overlap.

9. The electrochemical apparatus according to claim 1 wherein the outermost layer of the first current collector further comprises a step portion opposite to the flat portion, wherein the step portion comprises a first end connected to the first bending portion and a second end connected to the second bending portion, and the step portion extends from the second end to the first end in a winding manner; the electrode assembly further comprises a tape pasted to the outer surface of the first end portion and to the outer surface of the second end portion.

10. The electrochemical apparatus according to claim 9, wherein a projection of the tape in a direction perpendicular to the outer surface of the flat portion and a projection of the second winding adhesive in the direction perpendicular to the outer surface of the flat portion have an overlapping zone.

11. The electrochemical apparatus according to claim 9, wherein the electrode assembly has two second winding adhesives, a projection of the tape and a projection of the two second winding adhesives have overlapping zones in a direction perpendicular to the outer surface of the flat portion.

12. The electrochemical apparatus according to claim 9, wherein the electrode assembly further comprises a first winding adhesive that is located between the first tab and the second tab and that the first winding adhesive is stretched across the flat wound structure of the electrode assembly; a projection of the first winding adhesive along the direction perpendicular to the outer surface of the flat portion and a projection of the tape along the direction perpendicular to the outer surface of the flat portion have an overlapping zone in.

13. The electrochemical apparatus according to claim 2, wherein viewed along the direction of the winding axis, the first tab overlaps with the adhesive layer.

14. The electrochemical apparatus according to claim 13, wherein viewed along the direction of the winding axis, the second tab overlaps with the adhesive layer.

15. The electrochemical apparatus according to claim 3, wherein the electrode assembly is formed by winding together a first current collector, a second current collector, and a separator located between the first current collector and the second current collector, wherein a part of the first current collector forms the outermost current collector, and the adhesive layer is pasted between a surface of the outermost layer of the first current collector facing toward the winding center of the electrode assembly and a part of the separator adjacent to the outermost layer of the first current collector.

16. The electrochemical apparatus according to claim 9, wherein the second winding adhesive is located on the side of the tape facing away from the electrode assembly.

17. The electrochemical apparatus according to claim 2, wherein the second winding adhesive does not overlap with the adhesive layer.

18. The electrochemical apparatus according to claim 1, wherein the first connecting layer covers the edge of the outermost layer of the first current collector in the direction of the winding axis.

19. The electrochemical apparatus according to claim 1, wherein the first connecting layer is located on the side of the second winding adhesive facing away from the electrode assembly.

20. The electrochemical apparatus according to claim 2 wherein the first connecting layer is located on the side of the adhesive layer facing away from the electrode assembly.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0019] FIG. 1 is a three-dimensional diagram of an embodiment of an electrochemical apparatus of this application, where the electrochemical apparatus includes an electrode assembly and a packaging bag;

[0020] FIG. 2 is a three-dimensional diagram of the electrode assembly in FIG. 1;

[0021] FIG. 3 is a partial sectional diagram of FIG. 1 in a direction A-A with the packaging bag omitted;

[0022] FIG. 4 is an enlarged diagram of a local area in FIG. 3;

[0023] FIG. 5A is a partial top view of the electrochemical apparatus in FIG. 1 with the packaging bag omitted;

[0024] FIG. 5B is a partial bottom view of the electrochemical apparatus in FIG. 1 with the packaging bag omitted;

[0025] FIG. 6 is a partial sectional diagram of an embodiment of the electrochemical apparatus of this application;

[0026] FIG. 7 is a partial sectional diagram of an embodiment of the electrochemical apparatus of this application; and

[0027] FIG. 8 is a partial sectional diagram of an embodiment of the electrochemical apparatus of this application.

DETAILED DESCRIPTION

[0028] To make the objectives, technical solutions, and advantages of this application more comprehensible, the following describes this application in detail with reference to embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are merely used to explain this application but are not intended to limit this application.

[0029] In the descriptions of this application, it should be noted that, unless otherwise specified or defined explicitly, the terms mount, interconnect and connect are to be interpreted broadly. For example, they may refer to a fixed connection, a detachable connection, or an integral connection; may refer to a mechanical connection or an electrical connection or mutual communication; may refer to a direct connection or an indirect connection through an intermediate medium; and may refer to internal communication between two elements or interaction between two elements. A person of ordinary skill in the art can understand specific meanings of these terms in this application as appropriate to specific situations. The disclosure of this application provides many different embodiments or examples to implement different structures of this application. To simplify the disclosure of this application, the following only describes configurations and components of specific examples. Certainly, they are merely examples and are not intended to limit this application. In addition, this application may repeatedly use reference numerals and/or reference letters in different examples. Such repetition is intended to simply and clearly describe this application, and is not to indicate specific relationships between different embodiments and/or different configurations that are discussed herein.

[0030] FIG. 1 is a three-dimensional diagram of an embodiment of an electrochemical apparatus 1 of this application. The electrochemical apparatus 1 includes an electrode assembly 10 and a packaging bag 30. The packaging bag 30 is configured to accommodate at least a part of the electrode assembly 10. As shown in FIG. 1, the electrochemical apparatus 1 is defined to have a length direction along X, a height direction along Y, and a thickness direction along Z, where the X direction, Y direction and the Z direction are perpendicular to one another.

[0031] FIG. 2 is a three-dimensional diagram of an embodiment of the electrode assembly 10. The electrode assembly 10 has a winding structure. An outermost current collector of the electrode assembly 10 is labeled as 110. FIG. 3 is a sectional diagram of the electrochemical apparatus 1 of FIG. 1 in a direction A-A, where the packaging bag 30 is omitted in FIG. 3. The electrode assembly 10 further includes an adhesive layer 101 that is located adjacent to the outermost current collector 110.

[0032] The outermost current collector 110 includes a first bending portion 111 and a second bending portion 112 that are opposite to each other, and a flat portion 113 connected between the first bending portion 111 and the second bending portion 112. The adhesive layer 101 is pasted to a part of a surface of the flat portion 113 facing toward a winding center of the electrode assembly 10.

[0033] In some embodiments of this application, the electrochemical apparatus 1 may further include a first connecting layer 201. The first connecting layer 201 is configured to be pasted to the packaging bag 30 and the outermost current collector 110. The first connecting layer 201 includes a first surface that is opposite to an interior surface of the packaging bag 30 and a second surface that is opposite to the first surface, where the second surface of the first connecting layer 201 is pasted to a part of an outer surface of the first bending portion 111 and to a part of an outer surface of the flat portion 113. A projection of the first connecting layer 201 and a projection of the adhesive layer 101 in a direction perpendicular to the outer surface of the flat portion 113 have an overlapping zone D, as shown in FIG. 3. In some embodiments, a length of the overlapping zone D in the X direction may be any value between 0 mm and 20 mm. Further, the length of the overlapping zone D in the X direction may be any value from 0.5 mm and 20 mm. In some embodiments, the X direction may be in a direction parallel to a direction in which the first bending portion 111 and the second bending portion 112 face each other, and may be in a direction parallel to the outer surface of the flat portion 113.

[0034] FIG. 4 is an enlarged diagram of a local area K in FIG. 3. In some embodiments of this application, the electrode assembly 10 may include a first current collector 180, a second current collector 190, and a separator 199 located between the first current collector and the second current collector. The first current collector 180, the separator 199 and the second current collector 190 are wound together.

[0035] In some embodiments, the electrode assembly 10 further includes a first tab 11 and a second tab 12, where one end of the first tab 11 and one end of the second tab 12 extend from an inside of the electrode assembly 10 to an outside of the packaging bag 30, and the other end of the first tab 11 and the other end of the second tab 12 are electrically connected to the first current collector 180 and/or electrically connected to the second current collector 190.

[0036] In the embodiment of this application, a part of the first current collector

[0037] 180 forms the outermost current collector 110. The adhesive layer 101 is pasted between a surface of the outermost current collector 110 facing toward the winding center of the electrode assembly 10 and a part of the separator 199 that is immediately adjacent to the outermost current collector 110. A material of the adhesive layer 101 may include, but is not limited to, a double-sided adhesive.

[0038] In some embodiments, a material of the first current collector 180 includes aluminum, and a material of the second current collector 190 includes copper.

[0039] In some embodiments, the first current collector 180 is electrically connected to the first tab 11, and the second current collector 190 is electrically connected to the second tab 12.

[0040] In some embodiments, the electrode assembly 10 further includes a first active material 181 and a second active material 191. The first active material 181 may be applied on a part of a surface of the first current collector 180 except the outermost current collector 110, and the second active material 191 may be applied on a part of a surface of the second current collector 190.

[0041] Referring to FIG. 5A and FIG. 5B, the electrode assembly 10 further includes a first winding adhesive 13 that is located between the first tab 11 and the second tab 12 and that is stretched across the winding structure of the electrode assembly 10, and a second winding adhesive 14 that is located at a side of the electrode assembly 10 away from the first tab 11 and the second tab 12 and that is stretched across the winding structure of the electrode assembly 10. In some embodiments, the second winding adhesive 14 may be provided in a quantity of 2. This is not limited in this application.

[0042] In some embodiments, the first connecting layer 201 is pasted to a side of the first bending portion 111 that is close to the flat portion 113, and a tile length of the first connecting layer 201 is less than half a tile length of the first bending portion 111. In this way, the first connecting layer 201 would not cover a sealing zone of the electrode assembly 10, making it convenient for electrode to be injected or poured into the electrode assembly 10.

[0043] In some embodiments, the electrochemical apparatus 1 may further include a second connecting layer 202 that is spaced apart from the first connecting layer 201. The second connecting layer 202 is pasted to a part of an outer surface of the second bending portion 112 and to a part of the outer surface of the flat portion 113 adjacent to the second bending portion 112. A projection of the second connecting layer 201 and a projection of the adhesive layer 101 in a direction perpendicular to the outer surface of the flat portion 113 have an overlapping zone.

[0044] Although FIG. 3 shows the first connecting layer 201 that is close to the first bending portion 111 and the second connecting layer 202 that is close to the second bending portion 112, a person skilled in the art can understand that, in modifications or other embodiments of this application, the electrochemical apparatus 1 may include only one of the first connecting layer 201 and the second connecting layer 202, or the electrochemical apparatus 1 may include both the first connecting layer 201 and the second connecting layer 202. This is not limited in this application.

[0045] For the electrochemical apparatus 1 of this application, the connection between the electrode assembly 10 and the packaging bag 30 is strengthened through provision of the first connecting layer 201. When the electrochemical apparatus 1 drops or has a collision, the electrode assembly 10 and the packaging bag 30 are less likely to move relative to each other, effectively avoiding contraction of the separator 119, and preventing the outermost current collector 110 of the electrode assembly 10 from being torn out. In addition, the first connecting layer 201 and the second connecting layer 202 are correspondingly pasted to mainly the outer surface of the first bending portion 111 and the outer surface of the second bending portion 112. Accordingly, a contact area with the flat portion 113 of the outermost current collector 110 is small, which would not increase thickness of the electrode assembly 10 in the Z direction or increase volume of the electrode assembly 10. As a result, the electrochemical apparatus 1 of this application has relatively good energy density. Further, because the first connecting layer 201 and the second connecting layer 202 are respectively provided between the packaging bag 30 and the first bending portion of the outermost current collector 110 and between the packaging bag 30 and the second bending portion 112 of the outermost current collector 110, overall flatness of the electrode assembly 10 can be improved. This is especially the case for flatness of the part close to the first bending portion 111 and second bending portion 112 in the Z direction. Lithium precipitation causing black spots is thus reduced. Therefore, the electrochemical apparatus 1 of this application has high safety performance in withstanding drops, good energy density and good overall flatness.

[0046] It should be noted that the first connecting layer 201 and/or the second connecting layer 202 is applied to the interior surface of the packing bag 30. For the electrode assembly 10, application of glue to an outer surface of the outermost current collector 110 is not needed before the electrode assembly 10 is put into the packaging bag 30.

[0047] FIG. 6 is a partial sectional diagram of a modified embodiment of the electrochemical apparatus 1. The electrochemical apparatus 1 may further include a third connecting layer 203 and a fourth connecting layer 204 that are spaced apart from each other. The third connecting layer 203 is spaced apart from the first connecting layer 201. The fourth connecting layer 204 is spaced apart from the second connecting layer 202. The third connecting layer 203 is pasted to a part of the outer surface of the first bending portion 111, and the fourth connecting layer 204 is pasted to a part of the outer surface of the second bending portion 112. In this way, the electrochemical apparatus 1 in FIG. 6 includes the first connecting layer 201, the second connecting layer 202, the third connecting layer 203, and the fourth connecting layer 204. The four connecting layers facilitate relatively good overall flatness of the electrochemical apparatus 1.

[0048] In some embodiments, the outermost current collector 110 may further include a step portion 114 that is opposite to the flat portion 113. The step portion 114 includes a first end 114a connected to the first bending portion 111 and a second end portion 114b connected to the second bending portion 112. The second end portion 114b extends in a winding manner to the first end portion 114a. The third connecting layer 203 may further be pasted to a part of an outer surface of the first end portion 114a, and/or the fourth connecting layer 204 may further be pasted to a part of an outer surface of the second end portion 114b. In some embodiments, the electrode assembly 10 may further include a tape 15 that is pasted to the outer surface of the first end portion 114a and to the outer surface of the second end portion 114b.

[0049] FIG. 7 is a partial sectional diagram of a modified embodiment of the electrochemical apparatus 1. In some embodiments, the first connecting layer 201 may include a first gluing layer 2011 and a second gluing layer 2012 that are connected to each other, where the first gluing layer 2011 is pasted to the flat portion 113, the second gluing layer 2012 is pasted to the first bending portion 111, and a thickness of the first gluing layer 2011 is less than a thickness of the second gluing layer 2012. For example without limitation, the thickness of the second gluing layer 2012 may be 1.5 times the thickness of the first gluing layer 2011. It should be noted that the thickness may be a value measured along the Z direction.

[0050] FIG. 8 is a partial sectional diagram of a modified embodiment of the electrochemical apparatus 1. In some embodiments, the first connecting layer 201 includes a first gluing layer 2011 and a second gluing layer 2012, where the first gluing layer 2011 is pasted to the first bending portion 111 and to the flat portion 113, at least a part of the second gluing layer 2012 is provided on the first gluing layer 2011, and a projection of the second gluing layer 2012 and a projection of the adhesive layer 101 in a direction perpendicular to the outer surface of the flat portion 113 do not overlap. For example without limitation, the thickness of the second gluing layer 2012 may be 1.5 times the thickness of the first gluing layer 2011. It should be noted that the thickness may be a value measured along the Z direction.

[0051] A person skilled in the art can understand that the second connecting layer 202 may have a similar or same structure just as the first connecting layer 201 does. The structure of the first connecting layer 201 in the foregoing embodiments of this application can all be applied to the second connecting layer 202, or applied to the possibly present third connecting layer 203 and fourth connecting layer. Certainly, the first connecting layer 201, the second connecting layer 202, the third connecting layer 203, and the fourth connecting layer 204 may have a same structure or similar structures or have different structures. The structures of the first connecting layer 201, the second connecting layer 202, the third connecting layer 203, and the fourth connecting layer 204 in the foregoing embodiments may be used in combination or cross application with each other. Any substitutions, modifications and variations of the first connecting layer 201, the second connecting layer 202, the third connecting layer 203, and the fourth connecting layer 204 without creative efforts shall fall within the protection scope of this application.

[0052] Another embodiment of this application further provides an electric device, including the electrochemical apparatus 1 in the foregoing embodiments and modified embodiments. The electric device may include, but is not limited to, consumer electronic devices (mobile communication devices, notebook computers, wearable devices and the like), drones, electric tools, energy storage devices, electric bicycles, electric vehicles, and the like.

[0053] Although this application has been shown and described with respect to one or more embodiments, a person skilled in the art can come up with equivalent variations and modifications based on reading and understanding of this specification and the accompanying drawings. This application includes all such modifications and variations subject to only the scope of the appended claims. Specifically, for the functions performed by the foregoing components, unless otherwise indicated, terms used to described these components are intended to correspond to any components that perform the functions specified for such components (for example, they are equivalent in terms of functionality), even if they do not have structures that are equivalent to the disclosed structures for implementing the functions in the exemplary embodiments of this specification described herein. In addition, although specific features of this specification are disclosed with respect to only one of several embodiments, such features can be combined with one or more other features in other embodiments if such combinations are expected to be beneficial to given or specified applications. Further, it should be noted that a plurality described herein means two or more. The numeral suffixes in the steps described herein are merely to articulate embodiments for ease of understanding, not to entirely represent a sequential order of the steps being performed, and logical relations should be taken into consideration for determining the sequential order.

[0054] The foregoing descriptions are merely the embodiments of this application which are not intended to limit the patent scope of this application. Any equivalent structures or procedural modifications (such as combinations of technical features of different embodiments or direct or indirect applications to other related technical fields) made based on the content of the specification and drawings herein are included in the protection scope of this application.