Current collector, electrode sheet, and electrochemical device

Abstract

This application discloses a current collector, an electrode, and an electrochemical device, relating to the field of electrochemical energy storage technology. The current collector of this application includes an insulating layer and a conductive layer. The insulating layer includes a first surface and a second surface disposed opposite to each other along its thickness direction. The conductive layer is disposed on the first surface and the second surface respectively. The current collector also includes a plurality of spaced-apart first connectors, which protrude from the first surface and / or from the second surface. The first connectors are connected to the insulating layer and embedded in the conductive layer. This current collector is fixedly connected to the insulating layer through the first connectors and embedded in the conductive layer, effectively improving the bonding strength between the two, reducing the probability of delamination of the conductive layer and the insulating layer during cycle use, and improving the cycle life of the battery.

Description

Technical Field

[0001] This application relates to the field of electrochemical energy storage technology, and in particular to current collectors, electrodes and electrochemical devices. Background Technology

[0002] Electronic products are facing increasingly stringent safety requirements for their batteries. To prevent short circuits and thermal runaway caused by battery puncture, composite current collector structures are being used more and more frequently. Composite current collectors typically consist of an insulating layer and conductive layers connected to both sides of the insulating layer. The conductive layer is made of a metallic material, while the insulating layer is made of a polymer material. The insulating layer has good insulation properties and mechanical strength, and can effectively block the current path when the battery is punctured by external force, thereby reducing the risk of short circuits.

[0003] However, due to the low bonding strength between the conductive layer and the insulating layer, delamination and peeling are prone to occur during cyclic use, which is detrimental to the long cycle life of the battery. Utility Model Content

[0004] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes a current collector that is fixedly connected to the insulating layer through a first connector and embedded in the conductive layer, which effectively improves the bonding strength between the two, reduces the probability of delamination of the conductive layer and the insulating layer during cycle use, and improves the cycle life of the battery.

[0005] This application also proposes an electrode having the above-mentioned current collector.

[0006] This application also proposes an electrochemical device having the above-mentioned electrodes.

[0007] The current collector according to a first aspect embodiment of this application includes:

[0008] An insulating layer, the insulating layer comprising a first surface and a second surface disposed opposite to each other along its thickness direction;

[0009] A conductive layer is disposed on the first surface and the second surface, respectively;

[0010] The current collector further includes a plurality of spaced-apart first connectors, which protrude from the first surface and / or from the second surface. The first connectors are connected to the insulating layer and embedded in the conductive layer.

[0011] The current collector according to the embodiments of this application has at least the following beneficial effects:

[0012] The current collector of this application is provided with a first connector, which is fixedly connected to the insulating layer and embedded in the conductive layer. This indirectly increases the contact area between the conductive layer and the insulating layer, thereby effectively improving the bonding strength between the two and reducing the probability of the conductive layer and the insulating layer delaminating during cycle use, thus improving the cycle life of the battery.

[0013] According to some embodiments of this application, the first connector includes a main body extending along the thickness direction of the insulating layer, and a protrusion connected to the outer peripheral surface of the main body, the protrusion being disposed protruding from the outer peripheral surface of the main body.

[0014] According to some embodiments of this application, the outer diameter of the first connector gradually increases along the direction away from the insulating layer.

[0015] According to some embodiments of this application, the first connector and the insulating layer are integrally formed, and a plurality of the first connectors are formed on the first surface and the second surface respectively, and the first connectors are integrally embedded in the conductive layer on the corresponding side.

[0016] According to some embodiments of this application, the first connector passes through the insulating layer, and both ends of the first connector protrude from the first surface and the second surface, and are respectively embedded in the conductive layers on both sides.

[0017] According to some embodiments of this application, the insulating layer is provided with multiple sets of connection structures along the width direction of the current collector. Each set of connection structures includes multiple first connectors spaced apart along the length direction of the current collector. Each set of connection structures also includes a second connector extending along the length direction of the current collector. The second connector connects to each of the first connectors in the same set.

[0018] According to some embodiments of this application, the current collector further includes a plurality of third connectors, each of the third connectors extending along the width direction of the current collector and respectively connected to one of the first connectors in a different group of the connection structures.

[0019] According to some embodiments of this application, each group of connection structures includes a plurality of second connectors spaced apart along the thickness direction of the current collector. The first connector has a first side and a second side. When two adjacent second connectors in the same group are connected to the same first connector, one of the second connectors is connected to the first side of the first connector, and the other second connector is connected to the second side of the first connector.

[0020] Two adjacent first connectors in the same group are connected to the same second connector, and the second connector is connected to the first side of one of the first connectors and to the second side of the other first connector.

[0021] The electrode according to the second aspect of this application includes the current collector mentioned in any of the foregoing embodiments.

[0022] An electrochemical device according to a third aspect of this application includes the electrode mentioned in any of the foregoing embodiments.

[0023] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0024] The present application will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0025] Figure 1 This is a schematic diagram of the current collector structure according to an embodiment of this application;

[0026] Figure 2 This is a schematic diagram of the current collector structure according to another embodiment of this application;

[0027] Figure 3 This is a schematic diagram of the current collector structure according to another embodiment of this application;

[0028] Figure 4 This is a schematic diagram of the current collector structure according to another embodiment of this application;

[0029] Figure 5 for Figure 4 Enlarged view of region A in the middle;

[0030] Figure 6 This is a schematic diagram of the connection structure on the insulating layer according to another embodiment of this application;

[0031] Figure 7 for Figure 6 Enlarged view of region B in the middle;

[0032] Figure 8 for Figure 6 A sectional view of the middle structure;

[0033] Figure 9 for Figure 6 Side view of the middle structure;

[0034] Figure 10 for Figure 9 Enlarged view of region C in the middle;

[0035] Figure label:

[0036] Insulating layer 100; First surface 101; Second surface 102;

[0037] Conductive layer 200;

[0038] First connector 300; main body 310; protrusion 320;

[0039] Second connector 400;

[0040] Third connector 500; Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. The embodiments of this application may omit unnecessary detailed descriptions. For example, detailed descriptions of well-known matters and repeated descriptions of actually identical structures may be omitted. This is to avoid making the following description unnecessarily lengthy and to facilitate understanding by those skilled in the art.

[0042] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0043] As used herein, the terms “approximately,” “generally,” “substantially,” and “about” are used to describe and indicate small variations. When used in conjunction with an event or situation, the terms may refer to examples in which the event or situation occurred precisely and examples in which the event or situation occurred very approximately. For example, when used in conjunction with numerical values, the terms may refer to a range of variation less than or equal to ±10% of the numerical value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%. For example, if the difference between two values ​​is less than or equal to ±10% of the average of the values ​​(e.g., less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%), then the two values ​​can be considered "substantially" the same.

[0044] Furthermore, for ease of description, "first," "second," "third," etc., can be used in this article to distinguish different components of a figure or a series of figures. "First," "second," "third," etc., are not intended to describe the corresponding components.

[0045] Additionally, quantities, ratios, and other numerical values ​​are sometimes presented in range format in this document. It should be understood that such range format is for convenience and brevity and should be interpreted flexibly to include not only the numerical values ​​explicitly specified as range limits, but also all individual numerical values ​​or subranges covered within the range, as if each numerical value and subrange were explicitly specified.

[0046] In the detailed description and claims, a list of items connected by the terms "one of," "among," "a kind of," or other similar terms may mean any of the listed items. For example, if items A and B are listed, then the phrase "one of A and B" means only A or only B. In another example, if items A, B, and C are listed, then the phrase "one of A, B, and C" means only A; only B; or only C. Item A may contain a single element or multiple elements. Item B may contain a single element or multiple elements. Item C may contain a single element or multiple elements.

[0047] In the detailed description and claims, the list of items connected by the term "at least one of" can mean any combination of the listed items. For example, if items A and B are listed, then the phrase "at least one of A and B" means only A; only B; or A and B. In another example, if items A, B, and C are listed, then the phrase "at least one of A, B, and C" means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B, and C.

[0048] In the following description, all figures disclosed in this application are approximate values, regardless of whether the terms "about" or "approximately" are used in conjunction. They may vary by 1%, 2%, 5%, or sometimes 10% to 20%. Whenever a range of values ​​with a lower limit (RL) and an upper limit (RU) is disclosed, any values ​​falling within that range are specifically disclosed. Specifically, the following values ​​within that range are specifically disclosed: R = RL + k * (RU - RL), where k is a variable with a 1% increment from 1% to 100%, i.e., k is 1%, 2%, 3%, 4%, 5%, ... 50%, 51%, 52%, ..., 95%, 96%, 97%, 98%, 99%, or 100%. Furthermore, any range of values ​​defined by the two R values ​​as defined above are also specifically disclosed.

[0049] Throughout this specification, references to “implementation,” “partial implementation,” “one implementation,” “another approach,” “specific approach,” or “partial approach” mean that at least one implementation or embodiment in this application includes the specific features, structures, materials, or characteristics described in that implementation or embodiment.

[0050] In this application, numerical ranges are involved. Unless otherwise specified, the numerical ranges mentioned above are considered continuous and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Any lower limit can be combined with any upper limit to form a range not explicitly stated; and any lower limit can be combined with other lower limits to form a range not explicitly stated, just as any upper limit can be combined with any other upper limit to form a range not explicitly stated. Furthermore, each individually disclosed point or single value can itself serve as a lower or upper limit and be combined with any other point or single value or with other lower or upper limits to form a range not explicitly stated.

[0051] To address the aforementioned problems, this application proposes a composite current collector, such as... Figure 1 As shown, the current collector includes an insulating layer 100 and conductive layers 200 disposed on both sides of the insulating layer 100. The insulating layer 100 is made of a polymer material and has good insulation performance and mechanical strength, effectively blocking the current path when the battery is punctured by external force, thereby reducing the risk of short circuit. The conductive layers 200 are made of a metallic material and have good conductivity and thermal stability, ensuring that the battery can continuously and stably undergo charge-discharge cycles. When this current collector is used in the positive electrode, the conductive layer 200 can be an aluminum layer; when used in the negative electrode, the conductive layer 200 can be a copper layer.

[0052] The insulating layer 100 includes a first surface 101 and a second surface 102 disposed opposite to each other along its thickness direction. A conductive layer 200 is disposed on the first surface 101 and the second surface 102, and is tightly adhered to the insulating layer 100. In some embodiments, the conductive layer 200 is formed on the surface of the insulating layer 100 by sputtering, vapor deposition, or electroplating processes, ensuring good adhesion and conductivity between the conductive layer 200 and the insulating layer 100. The thickness of the conductive layer 200 can be adjusted according to battery design requirements.

[0053] To increase the bonding strength between the conductive layer 200 and the insulating layer 100, the current collector of this application further includes a plurality of spaced-apart first connectors 300. The first connectors 300 protrude from the first surface 101 and / or protrude from the second surface 102. In other words, the first connectors 300 may be disposed only on the first surface 101, only on the second surface 102, or simultaneously on both surfaces. The shape of the first connectors 300 may be columnar, conical, or sheet-like, and their material may be the same as or different from that of the insulating layer 100. One end of the first connector 300 is connected to the insulating layer 100, and the other end is embedded in the conductive layer 200.

[0054] It is understandable that the first connector 300 is fixedly connected to the insulating layer 100 and embedded in the conductive layer 200, which indirectly increases the contact area between the conductive layer 200 and the insulating layer 100, thereby effectively improving the bonding strength between the two, and thus reducing the probability of the conductive layer 200 and the insulating layer 100 delaminating during the cycle, and improving the cycle life of the battery.

[0055] In some embodiments, the first connector 300 includes a main body portion 310 and a protrusion portion 320, such as Figure 2 As shown, one end of the main body 310 is connected to the insulating layer 100, and the other end extends along the thickness direction of the insulating layer 100. The entire main body 310 is embedded inside the conductive layer 200. A protrusion 320 is connected to the outer peripheral surface of the main body 310 and protrudes from the outer peripheral surface of the main body 310. Figure 2 As shown, the protrusion 320 can be an annular protrusion, a plurality of protrusions spaced apart, or a protrusion block, etc., so that the outer diameter of the first connector 300 at the location of the protrusion 320 is larger than the outer diameter of the rest, thereby forming an anchoring structure inside the conductive layer 200. The presence of the protrusion 320 can effectively prevent the conductive layer 200 from peeling off from the insulating layer 100, and further enhance the bonding force between the two.

[0056] Furthermore, the protrusion 320 can also be as follows: Figure 3 The barbed structure shown has an outer diameter of the protrusion 320 that gradually increases in the direction away from the insulating layer 100. When the conductive layer 200 is subjected to external force, the barbed structure can produce a better anchoring effect on the conductive layer 200, thereby further improving the bonding strength between the conductive layer 200 and the insulating layer 100.

[0057] It is understandable that the protrusion 320 can be provided in the middle of the main body 310 (see reference). Figure 2 (as shown), or, the protrusion 320 may also be provided at the end of the main body 310 (see reference). Figure 3 (As shown).

[0058] In other embodiments, the first connector 300 may also be in the form of an inverted trapezoid, an inverted triangle, or other structures along the direction away from the insulating layer 100. That is, the outer diameter of the first connector 300 gradually increases along the direction away from the insulating layer 100, thereby also achieving the anchoring effect.

[0059] In some embodiments, such as Figures 1 to 3 As shown, the first connector 300 and the insulating layer 100 are integrally formed. For example, the insulating layer 100 can be manufactured by injection molding, or the first connector 300 and the insulating layer 100 can also be integrally formed using 3D printing technology. Integrating the first connector 300 and the insulating layer 100 not only simplifies the manufacturing process but also further improves the bonding strength and structural stability of the two. In this embodiment, no secondary processing or additional connection processes are required between the insulating layer 100 and the first connector 300, avoiding poor bonding problems caused by interface mismatch. Furthermore, the integrally formed structure can also achieve more complex geometric designs. Figures 1 to 3 As shown, the first surface 101 and the second surface 102 are respectively formed with a plurality of first connectors 300. It should be explained that "a plurality of" means one or more. The first connectors 300 are integrally embedded in the conductive layer 200 on the corresponding side to enhance the connection reliability between the conductive layer 200 and the insulating layer 100.

[0060] Unlike the one-piece molded structure described above, in some other embodiments, the first connector 300 is manufactured independently of the insulating layer 100 and then fixed to the insulating layer 100 by mechanical connection. For example, Figure 4 and Figure 5 In the illustrated embodiment, the insulating layer 100 is provided with mounting holes, and the first connector 300 passes through the mounting holes of the insulating layer 100. Both ends of the first connector 300 extend out of the first surface 101 and the second surface 102 to form protruding columnar structures on the first surface 101 and the second surface 102. The portion of the first connector 300 passing through the insulating layer 100 is fixedly connected to the insulating layer 100, and the portion of the first connector 300 protruding out of the insulating layer 100 is embedded in the conductive layer 200 on the corresponding side to achieve a stable connection between the conductive layer 200 and the insulating layer 100.

[0061] Furthermore, such as Figure 5 As shown, both ends of the first connector 300 are provided with protruding structures, so that the conductive layers 200 on both sides can be anchored and connected simultaneously through one first connector 300.

[0062] In some embodiments, the insulating layer 100 is provided with multiple sets of connection structures along its width direction. Each set of connection structures includes multiple first connectors 300 spaced apart along the length direction of the current collector. Each set of connection structures also includes second connectors 400 extending along the length direction of the current collector. The second connectors 400 connect to each of the first connectors 300 in the same set, thereby forming a mesh-like support skeleton extending along the thickness direction of the current collector. Thus, the support skeleton formed by the first connectors 300 and the second connectors 400 can not only improve the mechanical strength of the overall structure, but also effectively disperse external stress, avoiding tearing or damage to the conductive layer 200 caused by excessive local stress.

[0063] Furthermore, such as Figure 9 and Figure 10 As shown, each group of connection structures includes multiple second connectors 400 arranged at intervals along the thickness direction of the current collector. The first connector 300 has a first side and a second side. When two adjacent second connectors 400 in the same group are connected to the same first connector 300, one of the second connectors 400 is connected to the first side of the first connector 300, and the other second connector 400 is connected to the second side of the first connector 300.

[0064] In addition, two adjacent first connectors 300 in the same group are connected to the same second connector 400, and the second connector 400 is connected to the first side of one of the first connectors 300 and to the second side of the other first connector 300, thereby forming a woven support skeleton. This support skeleton has better tensile strength and structural stability, and can effectively prevent structural deformation or breakage caused by external forces.

[0065] Understandably, the current collector also includes multiple third connectors 500, such as... Figure 7 As shown, each third connector 500 extends along the width of the current collector and is connected to a first connector 300 in a different group of connection structures. Furthermore, the first connectors 300 in each group of connection structures are all on the same straight line, so that the third connectors 500 can be connected in series with the first connectors 300 in each connection structure along the width of the current collector, thus forming a three-dimensional mesh structure. This three-dimensional mesh structure not only improves the overall structural strength of the current collector but also enhances its stability and reliability under complex stress environments.

[0066] A second aspect of this application also provides an electrode sheet, which includes the current collector described in any of the foregoing embodiments. It is understood that the electrode sheet can be a positive electrode sheet or a negative electrode sheet, a single-sided sheet coated with an active material layer on one side, or a double-sided sheet coated with an active material layer on both sides. This electrode sheet can be used to form a battery cell through a stacking process or a winding process. This electrode sheet includes all the technical solutions mentioned in any of the foregoing embodiments, and therefore should have the beneficial effects mentioned in those embodiments, which will not be repeated here.

[0067] A third aspect of this application also proposes an electrochemical device, which includes any device that undergoes an electrochemical reaction to interconvert chemical energy and electrical energy. Specific, non-limiting examples include all types of primary batteries, secondary batteries, fuel cells, solar cells, or capacitors. In particular, the electrochemical device is a lithium secondary battery, including lithium metal secondary batteries, lithium-ion secondary batteries, lithium polymer secondary batteries, or lithium-ion polymer secondary batteries.

[0068] Although illustrative embodiments have been demonstrated and described, those skilled in the art should understand that the above embodiments should not be construed as limiting the present application, and that changes, substitutions and modifications can be made to the embodiments without departing from the spirit, principles and scope of the present application.

Claims

1. A current collector, characterized in that, include: An insulating layer, the insulating layer comprising a first surface and a second surface disposed opposite to each other along its thickness direction; A conductive layer is disposed on the first surface and the second surface, respectively; The current collector further includes a plurality of spaced-apart first connectors, which protrude from the first surface and / or from the second surface. The first connectors are connected to the insulating layer and embedded in the conductive layer.

2. The current collector according to claim 1, characterized in that, The first connector includes a main body extending along the thickness direction of the insulating layer, and a protrusion connected to the outer peripheral surface of the main body, the protrusion being disposed protruding from the outer peripheral surface of the main body.

3. The current collector according to claim 1, characterized in that, Along the direction away from the insulating layer, the outer diameter of the first connector gradually increases.

4. The current collector according to claim 1, characterized in that, The first connector and the insulating layer are integrally formed. A plurality of the first connectors are formed on the first surface and the second surface respectively. The first connectors are embedded in the conductive layer on the corresponding side.

5. The current collector according to claim 1, characterized in that, The first connector passes through the insulating layer, and its two ends protrude from the first surface and the second surface, respectively, and are embedded in the conductive layer on both sides.

6. The current collector according to claim 1, characterized in that, The insulating layer is provided with multiple sets of connection structures along the width direction of the current collector. Each set of connection structures includes multiple first connectors spaced apart along the length direction of the current collector. Each set of connection structures also includes a second connector extending along the length direction of the current collector. The second connector connects to each of the first connectors in the same set.

7. The current collector according to claim 6, characterized in that, The current collector also includes a plurality of third connectors, each of which extends along the width direction of the current collector and is connected to one of the first connectors in a different group of the connection structures.

8. The current collector according to claim 6, characterized in that, Each group of connection structures includes a plurality of second connectors arranged at intervals along the thickness direction of the current collector. The first connector has a first side and a second side. When two adjacent second connectors in the same group are connected to the same first connector, one of the second connectors is connected to the first side of the first connector, and the other second connector is connected to the second side of the first connector. Two adjacent first connectors in the same group are connected to the same second connector, and the second connector is connected to the first side of one of the first connectors and to the second side of the other first connector.

9. An electrode sheet, characterized in that, Includes the current collector as described in any one of claims 1 to 8.

10. An electrochemical device, characterized in that, Includes the electrode sheet as described in claim 9.

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