Composite current collector, pole piece and battery cell
By providing communication holes extending to the substrate layer on the metal conductive layer of the composite fluid collector and filling conductive fillers, the problem of poor conductivity of the composite fluid collector is solved, and higher conductivity and battery reliability and safety are achieved.
Patent Information
- Application Number
- CN202420958828.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-06
- Publication Date
- 2025-03-07
- Estimated Expiration
- 2034-05-06
AI Technical Summary
The existing composite liquid collector has poor conductivity and cannot meet the reliability and safety requirements of the battery at the same time.
A composite fluid collector is designed, including a substrate layer and two metal conductive layers, wherein at least one metal conductive layer is provided with a plurality of communication holes, and the communication holes extend into the substrate layer, and a conductive filler is provided therein to reduce the proportion of polymer polymer and electrical performance losses.
By reducing the proportion of polymer polymers, the loss of electrical properties is reduced, the overall conductivity of the composite liquid collector is improved, and the reliability and safety of the battery are enhanced.
Smart Images
Figure CN222581178U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of lithium batteries, and in particular to a composite current collector, a pole piece and a battery core. Background Art
[0002] With the continuous development of mobile energy storage technology, the reliability and safety of its adapted batteries are becoming more and more demanding. It is expected that the batteries can be used in a wider range of scenarios and reduce geographical restrictions while ensuring safety. Based on this, the metal foil current collectors conventionally used in batteries can no longer meet the above requirements at the same time. Composite current collectors have emerged, which combine the advantages of metal foil and polymers and can ensure the comprehensive performance requirements of batteries.
[0003] Composite current collector is a new type of current collector made of polymer materials and metals. Its structure is similar to a "sandwich" structure. The inner layer is a substrate layer made of polymer macromolecules (such as PP / PET / PI and other polymer materials), and the outer two layers are metal conductive layers (such as Al or Cu). However, due to the large thickness of the inner layer, the high proportion of polymer macromolecules, and the large loss of electrical properties, the overall conductivity of the current collector is poor. Utility Model Content
[0004] The main purpose of the utility model is to provide a composite current collector, aiming to solve the technical problem of poor conductivity of the existing composite current collector.
[0005] In order to achieve the above object, the utility model provides a composite current collector, which comprises:
[0006] substrate layer;
[0007] Two metal conductive layers are respectively disposed on two opposite sides of the substrate layer;
[0008] Among them, at least one of the two metal conductive layers is provided with a plurality of connecting holes, and the plurality of connecting holes respectively extend from a side surface of the metal conductive layer away from the substrate layer to the substrate layer, and at least one of the plurality of connecting holes is provided with a conductive filler embedded in the substrate layer.
[0009] In some embodiments, the conductive filler is a solid electrolyte filler.
[0010] In some embodiments, both metal conductive layers are provided with a plurality of connecting holes, the plurality of connecting holes on each metal conductive layer are arranged in sequence along the length direction of the substrate layer, and the connecting holes of the two metal conductive layers are staggered with each other in the length direction of the substrate layer.
[0011] In some embodiments, the ratio of the extension depth of the connecting hole in the substrate layer to the thickness of the substrate layer is in a range of 10% to 20%.
[0012] In some embodiments, the conductive filler in the communicating hole is flush with an outer surface of the metal conductive layer.
[0013] In some embodiments, the two metal conductive layers include a first metal conductive layer and a second metal conductive layer, wherein the first metal conductive layer is disposed on one of the two opposite side surfaces of the substrate layer, and the second metal conductive layer is disposed on the other of the two opposite side surfaces of the substrate layer.
[0014] In some embodiments, after the composite current collector is wound, the first metal conductive layer has a first straight region and a first corner region alternately arranged along the winding direction, and when a plurality of connecting holes are arranged on the first metal conductive layer, the plurality of connecting holes are distributed in the first straight region and the first corner region;
[0015] Wherein, the conductive filler is not provided in the connecting hole at the first corner area.
[0016] In some embodiments, after the composite current collector is wound, the second metal conductive layer has a second straight region and a second corner region alternately arranged along the winding direction, and when a plurality of connecting holes are arranged on the second metal conductive layer, the plurality of connecting holes are distributed in the second straight region and the second corner region;
[0017] Wherein, the conductive filler is not provided in the connecting hole at the second corner area.
[0018] The utility model also provides a pole piece, which comprises a current collector and an active material layer arranged on the current collector, and the current collector adopts the composite current collector as described above.
[0019] The utility model discloses a battery cell, which comprises a positive electrode sheet, a negative electrode sheet and a diaphragm, wherein the diaphragm is arranged between the positive electrode sheet and the negative electrode sheet;
[0020] Wherein, at least one of the positive electrode sheet and the negative electrode sheet adopts the electrode sheet as described above.
[0021] The composite current collector of the utility model comprises a substrate layer and two metal conductive layers, wherein the two metal conductive layers are respectively arranged on two opposite side surfaces of the substrate layer, wherein at least one of the two metal conductive layers is provided with a plurality of connecting holes, wherein the plurality of connecting holes respectively extend from a surface of the metal conductive layer on one side away from the substrate layer to the inside of the substrate layer, and at least one of the plurality of connecting holes is provided with a conductive filler embedded in the substrate layer. The composite current collector reduces the amount of polymer high molecular material in the substrate layer by providing a plurality of connecting holes extending to the substrate layer on the metal conductive layer, and simultaneously provides a conductive filler in at least one connecting hole for conduction, thereby reducing the proportion of polymer high molecular material, reducing electrical performance loss, and improving overall conductive performance. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 This is a schematic diagram of the structure of a composite current collector in one embodiment of the utility model;
[0023] Figure 2 This is a schematic diagram of the structure of a composite current collector in another embodiment of the present invention;
[0024] Description of Figure Numbers:
[0025] Label name Label name 100 Base material layer 220 Second metal conductive layer 200 Metal conductive layer 211 First straight area L Connecting hole 212 First Corner Area 10 Conductive filler 221 The second straight area 210 First metal conductive layer 222 Second Corner Area
[0026] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION
[0027] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the scheme in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0028] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back...) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.
[0029] It should also be noted that when an element is referred to as being "fixed on" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element at the same time. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element at the same time.
[0030] In addition, the descriptions of "first", "second", etc. in the present utility model are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.
[0031] In order to solve the shortcomings and defects of the current composite current collector pointed out in the background technology, the present utility model embodiment proposes a composite current collector, referring to Figure 1 The composite current collector includes: a substrate layer 100 and two metal conductive layers 200, wherein the two metal conductive layers 200 are respectively arranged on two opposite sides of the substrate layer 100; wherein at least one of the two metal conductive layers 200 is provided with a plurality of connecting holes L, wherein the plurality of connecting holes L respectively extend from a surface of the metal conductive layer 200 on one side away from the substrate layer 100 to the inside of the substrate layer 100, and at least one of the plurality of connecting holes L is provided with a conductive filler 10 embedded in the substrate layer 100.
[0032] The composite current collector involved in this embodiment is mainly used for pole pieces. Specifically, the pole piece is made by coating an active material layer on the composite current collector. Among them, the pole piece can be a positive pole piece or a negative pole piece, which is not limited. The composite current collector includes a substrate layer 100 and two metal conductive layers 200, and the two metal conductive layers 200 are respectively arranged on the opposite sides of the substrate layer 100, that is, the substrate layer 100 is located between the two metal conductive layers 200, and the whole presents a "sandwich" structure. Among them, the substrate layer 100 is a polymer polymer layer, which is made of a polymer polymer material. The polymer polymer material may include PP (polypropylene), PET (polyethylene terephthalate), PI (polyimide), etc., which is not limited. The metal conductive layer 200 can be made of metal materials such as aluminum and copper. It is easy to understand that when the composite current collector is applied to pole pieces of different polarities (such as positive pole pieces or negative pole pieces), the metal materials used in the metal conductive layer 200 are different.
[0033] In the two metal conductive layers 200, one of the metal conductive layers 200 may be provided with a plurality of connecting holes L, or both metal conductive layers 200 may be provided with a plurality of connecting holes L, which can be set according to actual conditions. When any metal conductive layer 200 is provided with connecting holes L, the number of connecting holes L provided on the metal conductive layer 200 is not limited. Moreover, when both metal conductive layers 200 are provided with connecting holes L, the number of connecting holes L provided on the two metal conductive layers 200 may be the same or different, which can be set according to actual conditions. Further, the plurality of connecting holes L extend from the surface of one side of the metal conductive layer 200 away from the substrate layer 100 to the substrate layer 100, that is, the connecting holes L are provided through the metal conductive layer 200 and extend in the substrate layer 100 at the same time, and the extension depth of the connecting holes L in the substrate layer 100 can be set according to actual conditions. Optionally, the extension depth of the connecting holes L in the substrate layer 100 does not exceed the thickness of the substrate layer 100. Among them, the connecting holes L can be columnar holes, etc., including but not limited to this.
[0034] At least one of the multiple connecting holes L on the metal conductive layer 200 is provided with a conductive filler 10 embedded in the substrate layer 100, that is, among the multiple connecting holes L on the metal conductive layer 200, the conductive filler 10 may be provided in some of the connecting holes L, or in all of the connecting holes L, which can be set according to actual conditions. Specifically, when the conductive filler 10 is filled in the connecting hole L, at least part of it is embedded in the substrate layer 100. The type of the conductive filler 10 can be set according to actual conditions. For example, in the field of batteries, any material that is suitable for transferring ions and can achieve conductivity can be used, and there is no limitation here.
[0035] The composite current collector of this embodiment reduces the amount of polymer high molecular material in the substrate layer 100 by providing a plurality of connecting holes L extending to the substrate layer 100 on the metal conductive layer 200, and simultaneously provides a conductive filler 10 in at least one connecting hole L for conduction, thereby reducing the proportion of polymer high molecular weight, reducing electrical performance loss, and improving overall conductive performance.
[0036] In some embodiments, the conductive filler 10 is a solid electrolyte filler. Among them, the solid electrolyte is an electrolyte with solidification characteristics at room temperature. As a solid ion conductor, it is used to transfer ions. The molecular structure of the solid electrolyte allows lithium ions to shuttle efficiently and keep the ion flow unimpeded. Compared with liquid electrolytes, solid electrolytes have the advantages of high safety, high stability and high voltage resistance. Optionally, the solid electrolyte includes a polymer electrolyte and an inorganic solid electrolyte. The polymer electrolyte is a polymer (PEO\PVDF\PAN) and a lithium salt (LiTFSI, LiFSI, LiClO4) obtained by coordination complexation; the inorganic solid electrolyte includes an oxide system and a sulfide system, and the oxide system includes LLTO with a perovskite structure, LLZO with a garnet structure, and a fast ion conductor (LISICON, NaSICON); the sulfide system is mainly composed of lithium sulfide and aluminum, phosphorus, silicon, titanium, aluminum and other elements. In this embodiment, by embedding a solid electrolyte in the connecting hole L, the low-temperature discharge performance can be effectively improved.
[0037] In some embodiments, reference Figure 1 , the two metal conductive layers 200 are each provided with a plurality of connecting holes L, and the plurality of connecting holes L on each metal conductive layer 200 are sequentially arranged along the length direction of the substrate layer 100, and the connecting holes L of the two metal conductive layers 200 are mutually dislocated in the length direction of the substrate layer 100. In this embodiment, the two metal conductive layers 200 are each provided with a plurality of connecting holes L, which can greatly reduce the proportion of polymer macromolecules and reduce the loss of electrical performance, thereby further improving the overall conductivity of the composite current collector. In addition, the connecting holes L of the two metal conductive layers 200 are mutually dislocated in the length direction of the substrate layer 100, which can avoid the setting of connecting holes L at the relatively same position on the two opposite sides of the substrate layer 100, thereby ensuring the structural strength of the substrate layer 100 and reducing the risk of fracture of the composite current collector.
[0038] In some embodiments, reference Figure 1, the ratio of the extension depth of the connecting hole L in the substrate layer 100 to the thickness of the substrate layer 100 is in the range of 10% to 20%. The ratio of the extension depth of the connecting hole L in the substrate layer 100 to the thickness of the substrate layer 100 can be set in the range of 10% to 20%. For example, the ratio of the extension depth of the connecting hole L in the substrate layer 100 to the thickness of the substrate layer 100 can be set to 10%, 15% or 20%. Taking the thickness of the substrate layer 100 as 5μm as an example, the extension depth of the connecting hole L in the substrate layer 100 can be set to 0.5μm to 1μm. Optionally, the ratio range of the extension depth of the connecting hole L in the substrate layer 100 to the thickness of the substrate layer 100 can be set based on the degree of the composite current collector conductivity requirement. For example, when the composite current collector conductivity requirement is low, the ratio of the extension depth of the connecting hole L in the substrate layer 100 to the thickness of the substrate layer 100 can be set to 10%; when the composite current collector conductivity requirement is medium, the ratio of the extension depth of the connecting hole L in the substrate layer 100 to the thickness of the substrate layer 100 can be set to 15%; when the composite current collector conductivity requirement is high, the ratio of the extension depth of the connecting hole L in the substrate layer 100 to the thickness of the substrate layer 100 can be set to 20%. This is only exemplary and not restrictive. In addition, the ratio of the extension depth of the connecting hole L in the substrate layer 100 to the thickness of the substrate layer 100 is in the range of 10% to 20%. By controlling the extension depth of the connecting hole L in the substrate layer 100, it is possible to avoid the connecting hole L from extending too deep in the substrate layer 100, thereby ensuring the structural strength of the substrate layer 100 and reducing the risk of fracture of the composite current collector.
[0039] In some embodiments, reference Figure 1 , the conductive filler 10 in the connecting hole L is flush with the outer surface of the metal conductive layer 200. In this embodiment, the flushing involved can be standard flushing or substantially flushing. When the conductive filler 10 is filled in the connecting hole L, it is filled to be flush with the outer surface of the metal conductive layer 200, which can greatly improve the conductive performance without protruding from the outer surface of the metal conductive layer 200.
[0040] In some embodiments, reference Figure 2 The two metal conductive layers 200 include a first metal conductive layer 210 and a second metal conductive layer 220 . The first metal conductive layer 210 is disposed on one of the two opposite side surfaces of the substrate layer 100 , and the second metal conductive layer 220 is disposed on the other of the two opposite side surfaces of the substrate layer 100 .
[0041] It is easy to understand that the composite current collector is combined with the active material to form a pole piece, and when the pole piece is wound to form a battery cell, the composite current collector will also be wound along with it.
[0042] In some embodiments, reference Figure 2 , after the composite current collector is wound, the first metal conductive layer 210 has a first straight region 211 and a first corner region 212 alternately arranged along the winding direction, and when a plurality of connecting holes L are arranged on the first metal conductive layer 210, the plurality of connecting holes L are distributed in the first straight region 211 and the first corner region 212;
[0043] The conductive filler 10 is not disposed in the connecting hole L at the first corner area 212 .
[0044] Specifically, after the composite current collector is wound, the first metal conductive layer 210 of the composite current collector is formed with a plurality of first straight regions 211 and a plurality of first corner regions 212. Taking the winding direction as a reference direction, the plurality of first straight regions 211 and the plurality of first corner regions 212 are arranged alternately one by one, that is, there is a first corner region 212 between any two adjacent first straight regions 211, and there is a first straight region 211 between any two adjacent first corner regions 212. When a plurality of connecting holes L are arranged on the first metal conductive layer 210, the plurality of connecting holes L are distributed in the first straight region 211 and the first corner region 212.
[0045] Among them, no conductive filler 10 is set in the connecting holes L at each first corner area 212 of the first metal conductive layer 210, so the electrolyte can be accommodated through the connecting holes L at each first corner area 212 of the first metal conductive layer 210 to increase the liquid retention, while releasing the corner stress and reducing lithium deposition at the corner position.
[0046] Optionally, a conductive filler 10 is disposed in the connecting hole L of the first straight region 211 .
[0047] In some embodiments, reference Figure 2 After the composite current collector is wound, the second metal conductive layer 220 has a second straight region 221 and a second corner region 222 alternately arranged along the winding direction. When a plurality of connecting holes L are arranged on the second metal conductive layer 220, the plurality of connecting holes L are distributed in the second straight region 221 and the second corner region 222;
[0048] Wherein, no conductive filler 10 is disposed in the connecting hole L at the second corner area 222 .
[0049] Specifically, after the composite current collector is wound, the second metal conductive layer 220 of the composite current collector is formed with a plurality of second straight regions 221 and a plurality of second corner regions 222. Taking the winding direction as a reference direction, the plurality of second straight regions 221 and the plurality of second corner regions 222 are arranged alternately one by one, that is, there is a second corner region 222 between any two adjacent second straight regions 221, and there is a second straight region 221 between any two adjacent second corner regions 222. When a plurality of connecting holes L are provided on the second metal conductive layer 220, the plurality of connecting holes L are distributed in the second straight regions 221 and the second corner regions 222.
[0050] Among them, no conductive filler 10 is set in the connecting holes L at each second corner area 222 of the second metal conductive layer 220, so the electrolyte can be accommodated through the connecting holes L at each second corner area 222 of the second metal conductive layer 220 to increase the liquid retention, while releasing the corner stress and reducing lithium deposition at the corner position.
[0051] Optionally, a conductive filler 10 is disposed in the connecting hole L in the second straight region 221 .
[0052] The embodiment of the utility model also proposes a pole piece, which includes a current collector and an active material layer arranged on the current collector, and the current collector is a composite current collector as described in the above embodiment. The specific structure of the composite current collector refers to the above embodiment. Since the pole piece adopts all the technical solutions of all the above embodiments, it has at least all the technical effects brought by the technical solutions of the above embodiments, which will not be repeated here. Among them, the pole piece involved can be a positive pole piece or a negative pole piece.
[0053] The present utility model also provides a battery cell, which comprises a positive electrode sheet, a negative electrode sheet and a separator, wherein the separator is arranged between the positive electrode sheet and the negative electrode sheet;
[0054] Among them, at least one of the positive electrode sheet and the negative electrode sheet adopts the electrode sheet as described in the above embodiment.
[0055] The specific structure of the pole piece refers to the above embodiment. Since the present battery cell adopts all the technical solutions of all the above embodiments, it at least has all the technical effects brought by the technical solutions of the above embodiments, which will not be described one by one here. Optionally, the battery cell is a wound battery cell or a laminated battery cell. Further, the battery cell can be packaged in a shell to make a battery.
[0056] The above description is only a partial or preferred embodiment of the present invention. Neither the text nor the drawings can limit the scope of protection of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the overall concept of the present invention, or direct / indirect application in other related technical fields are included in the scope of protection of the present invention.
Claims
1. A composite current collector, characterized in that: include: substrate layer; Two metal conductive layers are respectively disposed on two opposite sides of the substrate layer; Among them, at least one of the two metal conductive layers is provided with a plurality of connecting holes, and the plurality of connecting holes respectively extend from a side surface of the metal conductive layer away from the substrate layer to the substrate layer, and at least one of the plurality of connecting holes is provided with a conductive filler embedded in the substrate layer.
2. The composite current collector according to claim 1, characterized in that: The conductive filler is a solid electrolyte filler.
3. The composite current collector according to claim 1, characterized in that: The two metal conductive layers are both provided with a plurality of connecting holes, the plurality of connecting holes on each metal conductive layer are arranged in sequence along the length direction of the substrate layer, and the connecting holes of the two metal conductive layers are staggered with each other in the length direction of the substrate layer.
4. The composite current collector according to claim 1 or 3, characterized in that: The ratio of the extension depth of the connecting hole in the substrate layer to the thickness of the substrate layer is in the range of 10% to 20%.
5. The composite current collector according to claim 1 or 2, characterized in that: The conductive filler in the communicating hole is flush with the outer surface of the metal conductive layer.
6. The composite current collector according to claim 1, characterized in that: The two metal conductive layers include a first metal conductive layer and a second metal conductive layer. The first metal conductive layer is disposed on one of the two opposite side surfaces of the substrate layer, and the second metal conductive layer is disposed on the other of the two opposite side surfaces of the substrate layer.
7. The composite current collector according to claim 6, characterized in that: After the composite current collector is wound, the first metal conductive layer has a first straight region and a first corner region alternately arranged along the winding direction, and when a plurality of connecting holes are arranged on the first metal conductive layer, the plurality of connecting holes are distributed in the first straight region and the first corner region; Wherein, the conductive filler is not provided in the connecting hole at the first corner area.
8. The composite current collector according to claim 6, characterized in that: After the composite current collector is wound, the second metal conductive layer has a second straight region and a second corner region alternately arranged along the winding direction, and when a plurality of connecting holes are arranged on the second metal conductive layer, the plurality of connecting holes are distributed in the second straight region and the second corner region; Wherein, the conductive filler is not provided in the connecting hole at the second corner area.
9. A pole piece, characterized in that: The invention comprises a current collector and an active material layer arranged on the current collector, wherein the current collector is the composite current collector as claimed in any one of claims 1 to 8.
10. A battery cell, characterized in that: It includes a positive electrode sheet, a negative electrode sheet and a separator, wherein the separator is arranged between the positive electrode sheet and the negative electrode sheet; Wherein, at least one of the positive electrode sheet and the negative electrode sheet is the electrode sheet as claimed in claim 9.