Patent Application
20250158234
This application claims priority to Chinese Patent Application No. 202311509057.X, filed on Nov. 14, 2023, the disclosure of which is hereby incorporated by reference in its entirety.
This application relates to the field of battery technology, and in particular, to an electrode assembly, an electrochemical device, and an electronic device.
Lithium-ion batteries are widely used in the field of consumer electronics by virtue of many advantages such as high volumetric and gravimetric energy densities. However, with the advancement of technology, electrical devices are imposing higher requirements on the energy density of the lithium-ion batteries. How to optimize the structure of electrode assembly and further increase the energy density of the electrode assembly has become an urgent technical challenge.
This application provides an electrode assembly, an electrochemical device, and an electronic device to meet the above challenge.
Some embodiments of this application are implemented in the following way:
An electrode assembly is disclosed, where the electrode assembly includes a first electrode plate, a first tab, and a first insulation piece. The first electrode plate includes a first current collector and a first active material layer. The first active material layer is disposed on a surface of the first current collector. A part of the surface of the first current collector exposes the first active material layer to form a first groove. One end of the first tab is disposed in the first groove. Another end of the first tab extends along a width direction of the first electrode plate. The first tab is electrically connected to the first current collector. The first insulation piece includes a first portion and a protruding portion. The first portion covers the first groove. The protruding portion extends toward the first current collector. The first portion is fixed onto the first active material layer. The protruding portion covers the first tab. Along a length direction of the first electrode plate, a width of the protruding portion is less than or equal to a width of the first groove. The first portion and the protruding portion provide double-layer isolation protection for the tab, and avoid the need to affix insulation adhesive corresponding to the first groove onto the electrode plate opposite to the first electrode plate, thereby reducing the area of the insulation adhesive, reducing the coverage area of the insulation piece on the active material layer on the electrode plate, and increasing the energy density of the electrode assembly.
In the above embodiment, along the thickness direction of the first electrode plate, the sum of the thickness of the protruding portion, the thickness of the first tab, and the thickness of the first current collector is less than or equal to the thickness of the first electrode plate. In this way, the protruding portion is embedded in the first electrode plate, thereby reducing the protruding height of the first insulation piece at the first groove. On the one hand, this is conducive to reducing the thickness of the electrode assembly and increasing the energy density. On the other hand, this can improve the consistency of the surface of the electrode plate and improve the cycle performance of the electrode assembly.
In one or more of the above embodiments, along a thickness direction of the first electrode plate, a sum of a thickness of the protruding portion and a thickness of the first tab is less than or equal to a thickness of the first active material layer, thereby reducing the extent by which the protruding portion protrudes beyond the first active material layer, reducing the thickness of the electrode assembly, and increasing the energy density.
In one or more of the above embodiments, the electrode assembly further includes a separator. The separator is disposed on at least one side of the first electrode plate along a thickness direction of the first electrode plate. The first portion is fixed and connected to the separator, thereby alleviating displacement of the first insulation piece in the electrode assembly, and further improving the safety performance of the electrode assembly.
In one or more of the above embodiments, the first portion includes hot-melt adhesive. The first portion is bonded to the separator.
In one or more of the above embodiments, an adhesive layer is disposed on one side of the protruding portion, the side is oriented toward the first tab, and the adhesive layer is bonded to the first tab. In this way, the protruding portion keeps fixed to the tab, the first tab can be disposed synchronously with the protruding portion in the first groove, thereby simplifying the manufacturing process and avoiding the displacement of the protruding portion, where the displacement causes exposure of the metal structure in the first groove.
In one or more of the above embodiments, an adhesive layer is disposed on one side of the protruding portion, the side is oriented toward the first portion, and the adhesive layer is bonded to the first portion. In this way, the protruding portion keeps fixed to the first portion, and the protruding portion and the first portion can be connected into one. The protruding portion and the first portion are disposed at the first groove in the same process, thereby improving manufacturing efficiency.
In one or more of the above embodiments, an adhesive layer is disposed on one side of the first portion, the side is oriented toward the protruding portion, and the adhesive layer is bonded to the protruding portion, thereby fixing the protruding portion to the first portion.
In one or more of the above embodiments, the first electrode plate is a positive electrode plate.
In one or more of the above embodiments, the electrode assembly further includes a second insulation piece. The second insulation piece is disposed on a surface of the first active material layer. The second insulation piece is spaced apart from the first groove along a length direction of the first electrode plate.
In one or more of the above embodiments, the electrode assembly further includes a second electrode plate and a second tab. The second electrode plate and the first electrode plate are stacked. The second electrode plate includes a second current collector and a second active material layer. The second active material layer is disposed on a surface of the second current collector. A part of the second current collector exposes the second active material layer to form a second groove. A projection of the second insulation piece on the surface of the second active material layer covers the second groove. One end of the second tab is disposed in the second groove, and another end of the second tab extends along a width direction of the second electrode plate. The second tab is electrically connected to the second current collector. The second insulation piece is configured to isolate the second tab to prevent the burrs on the second tab from contacting the first electrode plate and causing an internal short circuit of the electrode assembly.
In one or more of the above embodiments, the electrode assembly further includes a third insulation piece. The third insulation piece is disposed on the second electrode plate. The third insulation piece covers the second current collector and the second tab in the second groove, so as to isolate the metal structure in the second groove.
In one or more of the above embodiments, along a length direction of the first electrode plate, a difference between a width of the first portion and a width of the first groove is 1 mm to 4 mm. By constraining the dimensional relationship between the first portion and the first groove, the first portion can fully cover the first groove and adhere to the first active material layer while maintaining the existing manufacturing accuracy, and alleviate the adverse effect on the energy density.
In one or more of the above embodiments, along a length direction of the first electrode plate, a difference between a width of the first groove and a width of the protruding portion is 0 mm to 4 mm, so that the protruding portion can be accommodated in the first groove while covering and shielding the metal structure in the first groove as much as possible.
In a possible embodiment, along a length direction of the first electrode plate, a difference between a width of the protruding portion and a width of the first tab is 0 mm to 5 mm, thereby reducing the risk that the tab structure in the groove is exposed outside the protruding portion due to process errors.
In one or more of the above embodiments, the first active material layer is disposed on surfaces of the first current collector on two opposite sides of the first current collector. The first groove is created on the first active material layers on both surfaces on the two opposite sides of the first current collector. The two first grooves are disposed correspondingly. The first tab is disposed in one of the first grooves. The groove structure created on both sides can reduce the difficulty of welding the tab to the first current collector. There are two first portions. The two first portions cover two first grooves respectively to prevent the burrs being exposed from the other groove.
In one or more of the above embodiments, along a width direction of the first electrode plate, a lateral edge of the protruding portion protrudes beyond a lateral edge of the first groove to prevent the metal structure in the first groove from being exposed due to manufacturing process errors, and enhance the safety performance. In one or more of the above embodiments, along a thickness direction of the first electrode plate, the electrode assembly satisfies: 2a+b≤c+80 μm, where a thickness of the protruding portion is a, a thickness of the first tab is b, and a thickness of the first electrode plate is c. The protruding portion may be partially embedded or not embedded in the first electrode plate. The energy density is increased by controlling the thickness of the first electrode plate, the thickness of the tab, and the thickness of the protruding portion to fall within an appropriate range.
An embodiment of this application further provides an electrochemical device. The electrochemical device includes a packaging shell and the electrode assembly disclosed in the above embodiment. The electrode assembly is disposed in the packaging shell.
An embodiment of this application further provides an electronic device.
The electronic device includes an electrical component and the electrochemical device disclosed in the above embodiment. The electrical component is electrically connected to the electrochemical device.
To describe technical solutions in embodiments of this application more clearly, the following outlines the drawings to be used in the embodiments. Understandably, the following drawings show merely some embodiments of this application, and therefore, are not intended to limit the scope. A person of ordinary skill in the art may derive other related drawings from the drawings without making any creative efforts.
This application is further described below with reference to the following specific embodiments and the foregoing drawings.
The following clearly and thoroughly describes the technical solutions in some embodiments of this application with reference to the drawings hereto. Evidently, the described embodiments are merely a part of but not all of the embodiments of this application.
It is hereby noted that a component referred to as being “fixed to” another component may be directly fixed onto the other component or may be fixed onto the other component through an intermediate component. A component considered to be “connected to” another component may be directly connected to the other component or may be connected to the other component through an intermediate component. A component considered to be “disposed on” another component may be directly disposed on the other component or may be disposed on the other component through an intermediate component. The terms “vertical”, “horizontal”, “left”, “right” and similar expressions used herein are merely for ease of description.
Unless otherwise defined, all technical and scientific terms used herein bear the same meanings as what is normally understood by a person skilled in the technical field of this application. The terms used in the specification of this application are merely intended to describe specific embodiments but not to limit this application. The term “and/or” used herein is intended to include any and all combinations of one or more relevant items recited.
The following describes some embodiments of this application in detail. To the extent that no conflict occurs, the following embodiments and the features in the embodiments may be combined with each other.
Referring to
In one of the embodiments of this application, along a width direction of the first electrode plate 10, a lateral edge of the protruding portion 32 protrudes beyond a lateral edge of the first groove 13 to prevent the metal structure in the first groove 13 from being exposed due to manufacturing process errors, and enhance the safety performance.
In one embodiment of this application, along the width direction of the first electrode plate 10, the protruding portion 32 protrudes beyond the lateral edge of the first groove 13 on one side protruding toward the first tab 20. The other side of the protruding portion 32 may be disposed in the first groove 13, and may further abut against the bottom wall of the first groove 13. In this way, the protruding portion 32 can shield the metal structure in the first groove 13 as far as possible. The metal structure in the first groove 13 may be the first tab 20, the first current collector 11, or the like. In another embodiment, along the width direction of the first electrode plate 10, the two opposite sides of the protruding portion 32 may protrude beyond the two opposite sides of the first groove 13 respectively, so as to further reduce the risk of exposure of the metal structure in the first groove 13.
Along a direction perpendicular to the thickness direction of the first electrode plate 10, the sum of the thickness of the protruding portion 32, the thickness of the first tab 20, and the thickness of the first current collector 11 is less than or equal to the thickness of the first electrode plate 10. This can reduce the extent by which the first insulation piece 30 protrudes out at the first groove 13. On the one hand, this is conducive to reducing the thickness of the electrode assembly 100 and increasing the energy density. On the other hand, this can improve the consistency of the surface of the electrode plate and improve the cycle performance of the electrode assembly 100.
In one embodiment, along the thickness direction of the first electrode plate 10, the sum of the thickness of the protruding portion 32 and the thickness of the first tab 20 is less than or equal to the thickness of the first active material layer 12, thereby preventing the protruding portion 32 from protruding beyond the first active material layer 12, reducing the thickness of the battery cell, and increasing the energy density.
In one possible embodiment, along the thickness direction of the first electrode plate 10, the electrode assembly satisfies: 2a+b≤c+80 μm, where the thickness of the protruding portion 32 is a, the thickness of the first tab 20 is b, and the thickness of the first electrode plate 10 is c. The units of a, b, and c are all μm. The thickness c of the first electrode plate 10 includes the thickness of the first current collector 11 and the thickness of the first active material layer 12, in μm. The protruding portion 32 may be partially embedded or not embedded in the first electrode plate 10. The thickness of the electrode assembly is reduced and the energy density is increased by controlling the thickness of the first electrode plate 10, the thickness of the tab, and the thickness of the protruding portion 32 to fall within an appropriate range.
Specifically, in the embodiment shown in
In some other embodiments, as shown in
Still referring to
In one embodiment, the first portion 31 includes hot-melt adhesive. The first portion 31 can be bonded to the separator 80 by hot-pressing, so as to fix the first portion 31 to the separator 80. When the first portion 31 is affixed to the first electrode plate 10, the separator 80 can keep fixed to the first electrode plate 10 through the first portion 31, thereby alleviating displacement of the first electrode plate 10 during charge-discharge cycles, and improving the electrical performance of the electrode assembly 100.
In a possible embodiment of this application, an adhesive layer is disposed on one side of the protruding portion 32, the side is oriented toward the first tab 20, and the adhesive layer is bonded to the first tab 20. In this way, the protruding portion 32 keeps fixed to the tab, the first tab 20 can be disposed synchronously with the protruding portion 32 in the first groove 13, thereby simplifying the manufacturing process and avoiding the displacement of the protruding portion 32, where the displacement causes exposure of the metal structure in the first groove 13.
Specifically, as shown in
In another embodiment, an adhesive layer is disposed on one side of the protruding portion 32, the side is oriented toward the first portion 31, and the adhesive layer is bonded to the first portion 31; and/or, an adhesive layer is disposed on one side of the first portion 31, the side is oriented toward the protruding portion 32, and the adhesive layer is bonded to the protruding portion 32. In this way, the protruding portion 32 keeps fixed to the first portion 31. The protruding portion 32 and the first portion 31 may be connected into one by the adhesive layer to form a hollow inverted-T structure. In the same manufacturing process, the protruding portion 32 and the first portion 31 are disposed at the first groove 13 simultaneously, the protruding portion 32 is accommodated in the first groove 13, and the first portion 31 covers the first groove 13, thereby improving the manufacturing efficiency.
Specifically, both the protruding portion 32 and the first portion 31 may be single-sided tape or double-sided tape. When both the protruding portion 32 and the first portion 31 are single-sided tape, the adhesive layers of the protruding portion and the first portion are disposed opposite to each other and bonded to each other. Before the first insulation piece 30 is affixed to the first electrode plate 10, the protruding portion 32 is bonded to the first portion 31 to form a hollow inverted-T structure first. When the first portion 31 is bonded to the first active material layer 12 to cover the first groove 13, the protruding portion 32 is embedded into the first groove 13 simultaneously. The side, oriented away from the first portion 31, of the protruding portion 32 may be spaced apart from or in contact with the surface of the first tab 20. Before the position of the first portion 31 is fixed, the protruding portion 32 may move relative to the first tab 20 to facilitate adjustment of the position at which the first insulation piece 30 is affixed, and improve the alignment accuracy. When the protruding portion 32 is double-sided tape and the first portion 31 is single-sided tape, after the protruding portion 32 is bonded to the first portion 31 to form a hollow inverted-T structure, the protruding portion 32 may be further bonded and fixed to the first tab 20 in the first groove 13, thereby increasing the bonding force between the first insulation piece 30 and the first electrode plate 10. When the protruding portion 32 is single-sided tape and the first portion 31 is double-sided tape, the hollow inverted-T structure formed by the protruding portion and the first portion can be bonded and fixed to both the first active material layer 12 and the separator 80 at the first groove 13 at the same time. When both the protruding portion 32 and the first portion 31 are double-sided tape, the hollow inverted-T structure formed by the protruding portion and the first portion can be bonded to the first tab 20, the first active material layer 12, and the separator 80 at the corresponding positions respectively, thereby improving the safety performance and electrical performance of the electrode assembly 100.
In an embodiment of this application, along the length direction of the electrode plate, the width of the first groove 13 is 8 mm to 15 mm, and the width of the first portion 31 is 10 mm to 20 mm. The width of the first portion 31 is greater than or equal to the width of the first groove 13, so that the first portion 31 can cover and shield the first groove 13. The width of the first tab 20 is 4 mm to 11 mm, and the width of the protruding portion 32 is 5 mm to 13 mm. The width of the protruding portion 32 is greater than or equal to the width of the first tab 20, so that the protruding portion 32 fully covers and shields the first tab 20.
Further, along the length direction of the first electrode plate 10, the difference between the width of the first portion 31 and the width of the first groove 13 is 1 mm to 4 mm. In an embodiment of this application, the difference between the width of the first portion 31 and the width of the first groove 13 may be 1 mm, 2 mm, 3 mm, 4 mm, or a value falling within a range formed by any two thereof. By constraining the dimensional relationship between the first portion 31 and the first groove 13, the first portion 31 can fully cover the first groove 13 while maintaining the existing manufacturing accuracy, and alleviate the adverse effect on the energy density.
Along the length direction of the first electrode plate 10, the difference between the width of the first groove 13 and the width of the protruding portion 32 is 0 mm to 4 mm, so that the protruding portion 32 can be accommodated in the first groove 13 while covering and shielding the metal structure in the first groove 13 as much as possible, thereby alleviating the exposure of the metal structure caused by fluctuation of the tolerance. In an embodiment of this application, the difference between the width of the first groove 13 and the width of the protruding portion 32 is 0 mm, 1 mm, 2 mm, 3 mm, 4 mm, or a value falling within a range formed by any two thereof.
Along the length direction of the first electrode plate 10, the difference between the width of the protruding portion 32 and the width of the first tab 20 is 0 mm to 5 mm, thereby reducing the risk that the tab structure in the groove is exposed outside the protruding portion 32 due to process errors. In an embodiment of this application, the difference between the width of the protruding portion 32 and the width of the first tab 20 is 0 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, or a value falling within a range formed by any two thereof.
In a specific embodiment, as shown in
In another embodiment, the protruding portion 32 may be disposed on one side of the first portion 31, the side being oriented away from the first tab 20. The projection of the protruding portion 32 in the first groove 13 covers the first tab 20. The protruding portion 32 is pressed into the first groove 13 from one side of the first portion 31, the side being oriented away from the first tab 20. In this way, a part of the first portion 31 is also accommodated in the first groove 13, thereby further reducing the thickness of the electrode assembly 100.
In another specific embodiment, as shown in
In another specific embodiment, as shown in
A layer of protruding portion 32 is disposed on the surface of the first tab 20 beforehand by means of thermal bonding, high-frequency bonding, or other means, so as to form a composite tab. The composite tab includes two parts: a metal layer and an insulation layer. The first tab 20 is the metal layer of the composite tab, and the protruding portion 32 is the insulation layer of the composite tab. The metal layer is 5 mm wide and 80 μm thick. The insulation layer is 5 mm wide and 16 μm thick. The first current collector 11 in the first groove 13 is connected to the metal layer of the composite tab by laser welding, riveting, or other means. The main material of the metal layer includes aluminum. The main material of the insulation layer includes polyethylene and/or polypropylene.
The two first portions 31 are disposed at the two first grooves 13 respectively. The width of the first portion 31 is 11 mm, thereby ensuring that the first groove 13 can be covered in a case of tolerance fluctuation. The difference between the width of the first portion 31 and the width of the first groove 13 is 2 mm. The difference between the width of the first groove 13 and the width of the protruding portion 32 is 2 mm. The difference between the width of the protruding portion 32 and the width of the first tab 20 is 0 mm.
Still referring to
In the prior art, the first electrode plate 10 is a positive electrode plate, and the second electrode plate 50 is a negative electrode plate. After being disposed in the first groove 13, the first tab is protected by an insulation piece. An insulation piece is also disposed on the negative electrode plate corresponding to the first groove 13. To avoid lithium plating, the area of the insulation piece disposed on the first groove 13 needs to be larger than the area of the insulation piece on the negative electrode plate corresponding to the first groove 13. In an embodiment of this application, the first electrode plate 10 is a positive electrode plate, and the second electrode plate 50 is a negative electrode plate. Because the protruding portion 32 and the first portion 31 are disposed at the first groove 13 of the first electrode plate 10, no additional insulation adhesive needs to be affixed to a position corresponding to the first groove 13 on the second electrode plate 50, and a first portion of a relatively small area can be disposed, thereby improving exertion of the capacity of the first electrode plate. Further, more second active materials are utilized efficiently, the second electrode plate 50 can provide more lithiation sites, thereby alleviating lithium plating. Further, the electrode assembly 100 further includes a third insulation piece 70. The third insulation piece 70 is disposed on the second electrode plate 50. The third insulation piece 70 covers the second current collector 51 and the second tab 60 in the second groove 53, so as to isolate the metal structure in the second groove 53, and prevent the burrs on the second tab 60 from piecing the separator 80 and contacting the first tab 20 to cause a short circuit. In addition, the third insulation piece 70 can cover a part of the first active material layer 12, so that the area of the second active material layer 52 is larger than the area of the first active material layer 12, thereby alleviating lithium plating.
The third insulation piece 70 may be an insulation adhesive. Along the length direction of the second electrode plate 50, the width of the third insulation piece 70 may be greater than the width of the second groove 53, so that the third insulation piece 70 is affixed to the surface of the second active material layer 52 and covers the second groove 53 to prevent the metal structure in the second groove 53 from being exposed. In another embodiment, the width of the third insulation piece 70 may be less than or equal to the width of the second groove 53 instead, so that the third insulation piece 70 can be accommodated in the second groove 53 like the protruding portion 32, thereby reducing the thickness of the second electrode plate 50 and further increasing the energy density of the electrode assembly 100.
Referring to
Referring to
The foregoing embodiments are merely intended for describing the technical solutions of this application but not intended as a limitation. Although this application is described in detail with reference to the foregoing exemplary embodiments, a person of ordinary skill in the art understands that modifications or equivalent substitutions may be made to the technical solutions of this application without departing from the spirit and scope of the technical solutions of this application.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202311509057.X | Nov 2023 | CN | national |
