CN213071179U

CN213071179U - Current collector for thick electrode and battery

Info

Publication number: CN213071179U
Application number: CN202021509263.2U
Authority: CN
Inventors: 郭永兴; 卢林
Original assignee: Jiangxi Star Energy Co ltd
Current assignee: Jiangxi Star Energy Co ltd
Priority date: 2020-07-27
Filing date: 2020-07-27
Publication date: 2021-04-27
Anticipated expiration: 2030-07-27

Abstract

The utility model relates to a battery preparation technical field, in particular to mass flow body and battery for thick electrode. The current collector includes: an interlayer space configured to accommodate an electrolyte; a current collector portion having at least one active material mounting surface configured to seat an active material; the active material setting surface is provided with at least one through hole communicated with the interlayer space, so that lithium ions in the electrolyte can enter the active material through the through hole and/or the lithium ions in the active material can enter the electrolyte through the through hole. Through the utility model discloses a design can realize lithium ion battery's thick electrode design, has improved the capacity of monomer electricity core greatly.

Description

Current collector for thick electrode and battery

Technical Field

The utility model relates to a battery preparation technical field, in particular to mass flow body and battery for thick electrode.

Background

The current energy storage technologies mainly include mechanical energy storage, chemical energy storage, electromagnetic energy storage, and phase change energy storage. Compared with other modes, the electrochemical energy storage has the advantages of convenience in use, less environmental pollution, no region limitation, no Carnot cycle limitation on energy conversion, high conversion efficiency, high specific energy and specific power and the like. The traditional electrochemical energy storage is mainly based on a lead-acid battery, the service life of the lead-acid battery is generally 2-3 years, and the service life of the wind energy and solar energy station cannot be matched at all. Since the commercialization of 1991, lithium ion batteries have rapidly developed and have dominated the digital and electric automobile fields. The vigorous development of wind-solar power generation in recent years has greatly pulled the development of energy storage lithium ion batteries and posed more challenges.

The capacity of the lithium ion battery monomer for the energy storage power station produced at present is basically less than 500Ah, the design concepts of 3C and EV are maintained, the volume and mass energy density are pursued, and the internal part of the monomer is lean solution. In order to design the energy storage capacity and the voltage, the energy storage power station needs to carry out a large amount of series-parallel connection work, and the monitoring cost of the single battery cell is greatly increased from dozens of to hundreds of watt hours of the single battery to dozens of to hundreds of megawatt hours of the single battery. Too small a cell capacity can reduce cell production efficiency. The thick electrode design can greatly increase the active material load on the current collector, greatly increase the capacity of a monomer battery core and reduce the ratio of inactive components, thereby improving the energy density of the battery and reducing the cost. However, the increase of the thickness of the electrode prolongs the transmission path of electrons and lithium ions, increases the impedance of the battery, has poor battery rate performance and electrode reaction kinetics, and has a series of problems of low bonding strength of an electrode coating, easy falling and the like, so that the utilization rate of materials is reduced and the energy density of the battery is reduced instead when the thickness of the electrode is infinitely increased.

Transport of lithium ions, comprising 3 parts: 1) the transport process of lithium ions in the electrolyte in the pores of the electrode is related to the porosity, the pore structure, the wettability of the electrode/electrolyte; 2) the diffusion process of lithium through the SEI film is affected by the SEI film composition, thickness, etc.; 3) the diffusion of lithium inside the solid particles of the electrode material is related to the basic characteristics of the raw material. As the thickness of the electrode increases, the transport of lithium ions in the pores of the electrode becomes the rate-determining step in the charging and discharging process of the battery, and therefore, prior art thick electrode designs have focused on improvements to the active material layer, such as, for example, pore size and its distribution, pore connectivity, pore throat characteristics, and the like. Improvements to the active materials have in turn led to a series of problems, for example, a reduction in the energy density of the battery, a considerable reduction in the bonding strength of the coating on the current collector.

In view of the above, it is necessary to provide a new concept to solve the above problems in the design of thick electrodes.

SUMMERY OF THE UTILITY MODEL

Based on this, an aspect of the present invention is to provide a current collector for a thick electrode, which can solve the problem of difficult lithium ion transmission in the thick electrode design and the problem of rapid battery performance degradation caused by the thick electrode in the prior art; another aspect of the present invention is to provide a battery based on the above current collector design.

In order to solve the above technical problem, the first aspect of the present invention is to provide a current collector for thick electrode, the current collector includes:

an interlayer space configured to accommodate an electrolyte;

a current collector portion having at least one active material mounting surface configured to seat an active material;

the active material setting surface is provided with at least one through hole communicated with the interlayer space, so that lithium ions in the electrolyte can enter the active material through the through hole and/or the lithium ions in the active material can enter the electrolyte through the through hole.

As an optional technical solution, the current collecting part comprises a first current collecting part and a second current collecting part, and the first current collecting part and the second current collecting part are separated to form the interlayer space;

the first collecting part and the second collecting part are respectively provided with a plurality of through holes;

at least one connecting part for connecting the first current collecting part and the second current collecting part is arranged at the edge or inside of the interlayer space.

As an optional technical solution, the first current collecting part and the second current collecting part are arranged in parallel with each other;

preferably, the first current collecting part and the second current collecting part are both planar structures;

preferably, the first current collecting part and the second current collecting part are rectangular structures with the same size and shape;

preferably, the connecting portion is vertically disposed on a plane of the first collecting portion.

As an optional technical scheme, the connecting part is at least one of a connecting upright post and a connecting strip;

preferably, the connecting columns are uniformly distributed in the interlayer space; and/or

The two connecting strips are arranged on the outer edges of the left side and the right side of the interlayer space, and the left side and the right side of the first flow collecting part and the second flow collecting part are fixedly connected by the two connecting strips respectively.

As an optional technical scheme, the active material setting surface is divided into two non-punching areas and a punching area according to whether through holes are distributed or not, the punching area is located in the middle of the length direction of the current collecting part, and the two sides of the punching area are the non-punching areas;

preferably, the punching area is a rectangular area, and the length L of the punching area₁1/2-4/5 of the length L of the collecting part.

As an optional technical scheme, a plurality of through holes are distributed in the punching area in a rectangular array; the connecting parts are distributed in the interlayer space rectangular array;

preferably, the through holes and the connecting parts are arranged in the punching area in a staggered manner;

preferably, the porosity of the current collector is 40-80%;

preferably, the inner diameter of the through hole ranges from 0.001 mm to 10mm, and more preferably ranges from 0.05 mm to 0.5 mm.

As an optional technical solution, the first current collecting portion and the second current collecting portion are both rigid structures, and the thickness of the first current collecting portion and the thickness of the second current collecting portion are independent ranges from 0.05 mm to 0.5 mm.

As an optional technical scheme, the value range of the interlayer space height is 0.01-1 mm.

As an optional technical scheme, the inner surface of the current collecting part is compounded with a leakage-proof material layer;

preferably, the flashing layer covers at least the punching zone.

As an alternative solution, when the connection part is at least partially an electric conductor, the polarities of the active materials arranged on the first current collecting part and the second current collecting part are the same;

when the connecting portions are all insulators, the polarities of the active materials on the first current collecting portion and the second current collecting portion are opposite.

As an optional technical solution, the thickness of the active material coated on the current collector ranges from 0.1mm to 10 mm.

Another aspect of the present invention is to provide a battery, which includes the current collector as described above, wherein the thickness of the active material coated on the current collector ranges from 0.1mm to 10 mm.

As an optional technical solution, the battery is a lithium ion battery;

preferably, the lithium ion battery is a lithium iron phosphate battery; and/or the battery is a battery for an energy storage system or a power battery for a vehicle.

Compared with the prior art, the utility model, the beneficial effect who has is: compare with conventional mass flow body among the prior art, the mass flow body of this application has the intermediate layer space, and in the battery use of assembly, its intermediate layer space has been full of electrolyte, compares traditional lithium ion battery's barren solution state, is the pregnant solution state in its battery. Form unique lithium ion transport passageway after through-hole that its mass flow body surface was seted up communicates with intermediate layer space, can show the transportation distance that shortens lithium ion in the active material granule, improve lithium ion's diffusion rate, based on this, when the active material of coating reaches conventional lithium ion battery several times thickness on the electrode, still can have better charge-discharge performance and circulation performance, based on this, the mass flow body that this application provided can realize thick electrode design.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:

fig. 1 is a schematic structural diagram of a current collector C1 for a thick electrode according to an embodiment of the present disclosure;

FIG. 2 is an enlarged view of a portion M of FIG. 1;

fig. 3 is a schematic half-sectional view of a current collector C1 for a thick electrode according to an embodiment of the present disclosure;

FIG. 4 is a schematic view of a connection and via arrangement on a current collector in one embodiment;

FIG. 5 is a schematic view of a connection and via arrangement on a current collector in another embodiment;

FIG. 6 is a schematic structural view of a connection and via arrangement on a current collector in another embodiment;

FIG. 7 is a schematic view of a connection and via arrangement on a current collector in another embodiment;

FIG. 8 is a schematic view of a connection and via arrangement on a current collector in another embodiment;

fig. 9 is a schematic structural diagram of an electrode P1 provided in the present embodiment;

FIG. 10 is a graph of the cycling performance of group A, group B and group C cells;

reference numerals: the current collector part-2, the active material arrangement surface-26, the first current collector part-21, the second current collector part-22, the through hole-212, the connecting part-23, the connecting upright post-231, the connecting strip-232, the interlayer space-7, the electrode-P1, the current collector C1, the active material layer-3, the punching area-261, the non-punching area-262 and the leakage-proof material layer-5.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the application, its application, or uses. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The relative arrangement of the components and steps, the numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present application unless specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate. In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

In the description of the present application, it should be understood that the terms "first", "second", etc. are used to define the components, and are used only for the convenience of distinguishing the corresponding components, and if not otherwise stated, the terms have no special meaning, and thus, should not be construed as limiting the scope of the present application.

In the description of the present application, it is to be understood that the orientation or positional relationship indicated by the directional terms such as "front, rear, upper, lower, left, right", "lateral, vertical, horizontal" and "top, bottom", etc., are generally based on the orientation or positional relationship shown in the drawings, and are used for convenience of description and simplicity of description only, and in the case of not making a reverse description, these directional terms do not indicate and imply that the device or element being referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore, should not be considered as limiting the scope of the present application; the terms "inner and outer" refer to the inner and outer relative to the profile of the respective component itself.

The present application is directed to the preparation of thick electrode coated batteries through improvements to current collector C1, which current collector C1 is suitable for lithium ion batteries, such as ternary batteries and lithium iron phosphate batteries, through these improvements of the present application, a thick electrode design of a cell can be achieved, the capacity of which is very large. The device is particularly suitable for being used as an energy storage device and an electric energy conversion device of an automobile. The present application is described in detail below with reference to the accompanying drawings.

As shown in fig. 1 to 3, the current collector C1 for thick electrode provided in this embodiment is very suitable for manufacturing a current collector for thick electrode of a laminated battery, and it is understood that the laminated battery in this application refers to a battery in which electrodes are produced by a lamination process.

Current collector C1 in the present application includes an interlayer space 7 configured to accommodate an electrolyte; a header 2, said header 2 having at least one active material placement surface 26 configured to seat an active material; wherein the active material disposing surface 26 is opened with at least one through hole 212 communicating with the interlayer space 7, so that lithium ions in the electrolyte can enter the active material through the through hole 212 and/or lithium ions in the active material can enter the electrolyte through the through hole 212. The size and shape of the through-hole 212 are not particularly limited, and lithium ions may pass through the through-hole. In a preferred embodiment, a plurality of through holes 212 are formed on both the first collecting portion 21 and the second collecting portion 22.

Fig. 2 shows a partial enlargement of the region M in fig. 1, and it can be seen from fig. 2 that the current collecting part 2 includes a first current collecting part 21 and a second current collecting part 22, and the first current collecting part 21 and the second current collecting part 22 are separated to form the interlayer space 7; at least one connecting part 23 connecting the first collecting part 21 and the second collecting part 22 is arranged at the edge or inside of the interlayer space 7. In the specific embodiment of fig. 2, a connecting portion 23 connecting the first collecting portion 21 and the second collecting portion 22 is provided at the edge of the interlayer space 7, and the connecting portion 23 has a bar shape.

In some specific embodiments, the connection portion 23 and the first and

second collecting portions

21 and 22 may be manufactured by an integral casting process or a bending process. In addition, a plurality of through holes 212 allowing lithium ions to pass through are formed in each of the first current collecting portion 21 and the second current collecting portion 22, so that at least part of the through holes 212 are ensured to be communicated with the interlayer space 7, and lithium ions in the active material on the current collecting portion 2 side can pass through the through holes 212 and enter and exit the interlayer space 7.

Compared with the conventional current collector in the prior art, the current collector C1 has the interlayer space 7, and when the assembled battery is used, the interlayer space 7 is filled with electrolyte, so that the current collector is in a rich liquid state compared with the lean liquid state of the conventional lithium ion battery. A through hole 212 formed in the surface of the lithium ion battery is communicated with an interlayer space 7 in the middle to form a unique lithium ion transport channel, the lithium ion transport distance is reduced by half, taking the first current collecting part 21 as an example, after the active material is coated, lithium ions in the active material on the side of the first current collecting part 21 can flow into electrolyte through the channel between the through hole 212 and the interlayer space 7, the transport distance of the lithium ions in active material particles can be remarkably shortened by half, the problem that the transport path of the active material on the side of the current collecting part is long in the conventional technology is solved, the diffusion speed of the lithium ions is improved, and based on the problem, the design of a thick electrode of the battery can be realized.

As a specific embodiment, in order to facilitate mass production of the current collector C1 and subsequent arrangement of active materials, in the current collector C1 shown in fig. 1-2 of the present application, the first current collecting portion 21 and the second current collecting portion 22 are arranged in parallel up and down; the first current collecting part 21 and the second current collecting part 22 are both planar structures; the first current collecting part 21 and the second current collecting part 22 are rectangular structures with the same size and shape; the connecting portion 23 is vertically disposed on the plane of the first current collecting portion 21.

In order to ensure that the manufactured current collector C1 has a relatively stable capacity in the use process and facilitates the arrangement of active materials, the first current collecting part 21 and the second current collecting part 22 are both rigid structures, and the thickness of the first current collecting part 21 and the thickness of the second current collecting part 22 are respectively and independently in a range of 0.05-0.5 mm.

The materials of the first current collector 21 and the second current collector 22 are not particularly limited as long as they do not cause chemical changes in the manufactured secondary battery and have high conductivity, and when they are used as a positive electrode current collector, they may be made of stainless steel, aluminum, nickel, titanium, sintered carbon, or aluminum or stainless steel surface-treated with carbon, nickel, titanium, silver, or the like. In addition, the current collector may be used in any of various forms including a film, a sheet, a foil, a mesh, a porous structure, a foam, and a non-woven fabric. When it is used as a negative electrode current collector, the material thereof may be made of copper, stainless steel, aluminum, nickel, titanium, sintered carbon, copper or stainless steel surface-treated with carbon, nickel, titanium or silver, and aluminum-cadmium alloy. In addition, the current collector may be used in any of various forms including a film, a sheet, a foil, a mesh, a porous structure, a foam, and a non-woven fabric.

In the present application, the connection portion 23 is provided to effectively separate the first collecting portion 21 and the second collecting portion 22, so as to maintain the capacity and shape of the interlayer space 7 relatively stable, and more importantly, the connection portion 23 is provided to effectively increase the rigidity of the collecting portion 2, and the connection portion 23 is not particularly limited in material, can be fixedly connected to the collecting portion and has a certain rigidity, and may have any shape such as a needle shape, a rod shape, a column shape, a long strip shape, a sheet shape, and a cross-sectional shape such as a circle, a star shape, and a polygon shape.

The structure of the connection part 23, which is described in detail below, as the connection part 23 connecting the first collecting part 21 and the second collecting part 22, the connection portion 23 can greatly improve the rigidity of the current collector by fixedly connecting the first current collecting portion 21 and the second current collecting portion 22, the connection portion 23 and the first collecting portion 21 and the second collecting portion 22 may be formed by casting, bonding, welding, or bending, the connection portion 23 may be a connection post 231 and/or a connection bar 232, wherein, the distribution method of the connecting parts 23 in the interlayer space 7 can adopt a regular or irregular distribution mode, the cross section of the connection post 231 may be circular, polygonal, etc., the connection bar 232 is formed in an elongated shape, and the length of the connection bar 232 ranges from 1/4 times to 1 time the width of the collecting portion 2.

The following description is made with reference to fig. 4-8, respectively: as a specific embodiment, as shown in fig. 4 or 5, the connecting portion 23 is a connecting pillar 231 having a circular cross section, and the connecting pillars 231 are uniformly distributed in the interlayer space 7, and as another embodiment, as shown in fig. 6, the connecting portion 23 includes a connecting bar 232 and a connecting pillar 231, wherein the connecting pillar 231 is uniformly distributed in the middle (portion covering the active material) of the interlayer space 7, the connecting bar 232 is two pieces disposed at the outer edges of the left and right sides of the interlayer space 7, and the two pieces of the connecting bar 232 fixedly connect the left and right sides of the first collecting portion 21 and the second collecting portion 22, respectively. As another embodiment, as shown in fig. 7, the connecting portion 23 is a connecting bar 232, and the connecting bar 232 is uniformly distributed in the length direction of the interlayer space 7. As shown in fig. 8, the connection portions 23 are connection bars 232 with different lengths, the connection bars 232 at both sides select current collectors with the same width, and the connection bars at the middle portion may be arranged in an up-down crossing manner, so that the electrolyte inside the current collector may better circulate in the length direction of the current collector than the current collector in fig. 7 while maintaining the better rigidity of the current collector.

As will be described in detail below, the arrangement of the through holes 212 is divided into two non-punched areas 262 and one punched area 261 according to whether or not there are through holes 212 distributed on the active material arrangement surface 26 of the current collecting part 2, the punched area 261 being located at the middle in the longitudinal direction of the current collecting part 2, the non-punched areas 262 being located on both sides of the punched area 261, according to fig. 1; also, it is preferable that both outer surfaces of the collecting portion 2 are designed as described above to reduce the proportion of inactive materials. The punching zone 261 is a rectangular zone, the length L of the punching zone 261₁1/2-4/5 of the length L of the first collecting portion 21.

The through holes 212 may be regularly or irregularly distributed on the surface of the first collecting part 21 or the surface of the second collecting part 22, and the shape of the through holes includes, but is not limited to, a circle, a star, an ellipse, a semicircle, any polygon, and the like, and preferably, the shape is a circle.

As a specific embodiment, in fig. 4-5, a plurality of the through holes 212 are distributed in a rectangular array in the punching zone 261, and fig. 4 and 5 show two rectangular array distributions, and preferably the distribution shown in fig. 5; similarly, the connecting pillars 231 are arranged in a rectangular array in the interlayer space 7; the through holes 212 are arranged offset from the connection portions 23 in the punching region 261.

As a specific embodiment, the porosity of the current collector C1 ranges from 40% to 80%, it being understood that porosity refers to the percentage of open area and the total area of the current collector coated with active material. If the porosity is too small, the contact area between the portion of the active material close to the surface of the current collector and the electrolyte in the interlayer space 7 is too small, which affects the movement of lithium ions in the active material, and if the porosity is too large, the rigidity of the current collector is insufficient. The inner diameter of the through hole 212 of the first collecting portion 21 or the second collecting portion 22 ranges from 0.001 mm to 10mm, and preferably, the inner diameter of the through hole 212 ranges from 0.05 mm to 0.5 mm.

When the inner diameter of the through hole 212 is smaller, the active material coated on the surface of the through hole is not easy to fall off through the through hole, and the leakage-proof material layer 5 is not required to be added. When the inner diameter of the through hole 212 is set to be larger, the active material on the through hole 212 may be in danger of falling off, and a leakage-proof material layer 5 may be added. The leakage preventing layer 5 may be provided at an inner surface or an outer surface of the first header 21 and/or the second header 22. Sized to cover at least the punched area 261 on current collector C1; the material of the leakage-proof layer 5 may be any material that can allow lithium ions to pass through, and specific choices of the material include, but are not limited to, films, sheets, foils, nets, porous structures, foams, non-woven fabrics, microporous foils or membranes, wherein microporous foils or membranes are preferred.

As a preferred embodiment, as shown in fig. 9, the inner surface of the punched region 261 of the first collecting portion 21 is compounded with the leakage preventing material layer 5, and the inner surface of the punched region 261 of the second collecting portion 22 is compounded with the leakage preventing material layer 5. The advantage of disposing the anti-leakage material layer 5 on the inner surface of the first current collecting portion 21/the second current collecting portion 22 is that the anti-leakage material layer 5 not only can prevent the active material in the through hole 212 from falling off, but also can form a plurality of concave circular grooves on the outer surface of the first current collecting portion 21/the second current collecting portion 22 together with the through hole 212, and the circular grooves can be filled with the active material, so as to reduce the proportion of the inactive material of the electrode, and also can enhance the bonding force between the active material and the first current collecting portion 21/the second current collecting portion 22.

The present application also provides some electrode structures designed based on the current collector C1 structure described above, as shown in fig. 9, the electrode P1 includes a current collector C1; and an active material layer 3 containing an active material disposed on at least one outer surface of the current collector C1; the thickness of the active material layer 3 ranges from 0.1mm to 10 mm.

In some preferred embodiments, as shown in fig. 9, the utilization rate of the current collector C1 may be improved by providing an active material layer 3 on both outer surfaces of the current collector C1, the active material layer 3 being provided on the punching region 261 of the first current collecting portion 21 and/or the second current collecting portion 22. The active material layer 3 may be formed on the outer surface of the current collector C1 by bonding or coating, the active material layer 3 may be a positive electrode active material or a negative electrode active material, and examples of applications of the positive electrode active material include compounds capable of reversibly deintercalating and intercalating lithium ions, such as lithium cobaltate, lithium manganate, lithium nickelate and ternary materials having a layered structure; also included are lithium nickel manganese oxide having a spinel structure and lithium iron phosphate having an olivine structure. Examples of applications of the negative electrode active material include a carbon material capable of intercalating and deintercalating lithium ions, lithium metal, silicon, and tin.

In one embodiment, when the connection portion 23 is at least partially an electrical conductor (e.g., the same material as the current collector 2 is selected), the polarities of the active material layers 3 on the first current collector 21 and the second current collector 22 are the same, and the entire electrode P1 is used as a positive electrode or a negative electrode.

In other embodiments, when the connection portion 23 is entirely an insulator, the first current collector 21 and the second current collector 22 may be coated with active materials having opposite polarities. In this case, the entire electrode P1 may include one positive electrode and one negative electrode, and the first current collecting portion 21 and the second current collecting portion 22 of the current collecting portion 2 may be used as the positive electrode and the negative electrode, respectively. For example, the first current collecting portion 21 serves as a positive electrode current collector, the second current collecting portion 22 serves as a negative electrode current collector, and respective active materials are disposed on the surfaces thereof. In this structure, lithium ions in the active material between the two current collecting portions on the same current collector C1 can be directly exchanged through the interlayer space 7, and the transport path of lithium ions in the active material and the electrolyte is short. When the adjacent electrodes P1 are stacked in an alternating arrangement, i.e., (cathode + anode)/(anode + cathode)/(cathode + anode), the use of a separator can be avoided and the transport path of lithium ions in the active material is halved.

The present embodiment provides a battery comprising an electrode P1, the electrode P1 comprising a current collector C1; and an active material layer 3 containing an active material disposed on at least one outer surface of the current collector C1; through adopting the mass flow body C1 that this application provided, the value range of 3 thicknesses of active material layer is 0.1 ~ 10 mm.

Compared with the thickness of the active material of the common battery in the prior art, the thickness of the single active material of the battery is obviously increased, and the capacity of a single battery cell is larger, so that the single active material of the battery is suitable for being used as an electric energy conversion device of large-scale equipment such as an energy storage power station, a power battery for a vehicle and the like. The battery is a lithium ion battery, the lithium ion battery is a lithium iron phosphate battery, and the battery is the lithium iron phosphate battery for the energy storage system.

The single-sided positive electrode of the battery manufactured by the conventional current collector is generally 60-80 μm thick, and the negative electrode is generally 55-65 μm thick. In this application, its mass flow body C1 has intermediate layer space 7, forms unique lithium ion transportation passageway after through-hole 212 that its surface was seted up communicates with intermediate layer space 7, and lithium ion transportation distance reduces half, consequently, sees from lithium ion diffusion path alone, adopts the mass flow body of this application, can guarantee that each item electrochemical performance of battery does not reduce when active material layer 3 thickness increases to the twice of conventional thickness. Meanwhile, after the current collector is assembled into a battery for use, the interlayer space 7 of the current collector is filled with electrolyte, and compared with the poor liquid state of the traditional lithium ion battery, the current collector is in a rich liquid state, so that various performances of the battery can be further comprehensively improved, finally, the electrode thickness (namely the thickness of the active material layer 3) of the current collector can reach 6 times of that of the conventional current collector battery, the battery performance of the battery can still be maintained, and the test proves that the battery performance test data of the current collector when the electrode thickness reaches 6 times of the conventional thickness.

The test is divided into three groups, and batteries are respectively prepared and tested for different multiplying power discharge capacities, energy efficiency and cycle performance data according to the following conditions:

grouping tests:

group A: the thickness of a single-sided positive active material of a traditional current collector, a positive electrode 13um aluminum foil and a negative electrode 8um copper foil is 72.5um, and the negative electrode is 54.0 um;

group B: the thickness of the single-sided positive active material is 435um and 324 um;

group C: use the current collector of this application, wherein:

and (3) positive electrode: a current collector is a 10.2 mm aluminum plate, 60% of round holes are formed, and the diameter of each round hole is 0.5 mm; the current collector is a 20.2 mm aluminum plate, the diameter of each circular hole is 0.5mm, and the distance between the current collectors 1 and 2 is 0.1 mm; the thickness of the single-sided anode active material is 435 um;

negative electrode: a current collector is a copper plate with the diameter of 10.15 mm, 70% of round holes are formed, and the diameter of each round hole is 0.8 mm; a copper plate with the diameter of 20.15 mm and 70% of round holes with the diameter of 0.8mm are arranged, the distance between the current collectors 1 and 2 is 0.1mm), and the coating thickness of the negative active material is 324 um;

the design capacities of the above A, B, C three groups of cells were all 4100mAh, and the detailed design is shown in table 1:

table 1 detailed parameter configuration of three batteries

The three groups of batteries are respectively tested for discharge capacity and charge-discharge energy efficiency under the discharge rate of 0.33-3C, and the results are shown in table 2:

TABLE 2 discharge capacity at different rates and energy efficiency

As can be seen from table 2 above, the discharge capacity and the 1C charge-discharge energy efficiency of the group B at different magnifications are both lower than those of the group a, and the discharge capacity reduction amplitude of the group B at a large magnification tends to increase, and at 0.33C magnification, the discharge capacity is reduced by 6.1% compared with the group a, at 3C magnification, the discharge capacity is reduced by 9.9% compared with the group a, and at 1C magnification, the charge-discharge energy efficiency is reduced by 2.5% compared with the group a; it can be seen that the use of conventional current collectors to fabricate thick electrodes can result in a decrease in the discharge capacity and charge-discharge energy efficiency of the battery.

From the discharge capacity and the 1C charge-discharge energy efficiency under different multiplying powers, the discharge capacity and the 1C charge-discharge energy efficiency of the group C are slightly lower under the multiplying power of 0.33C-1C, and as the multiplying power is increased, the discharge capacity of the group C is higher than that of the group A under the multiplying powers of 2C and 3C, so that the group C and the group A are generally equal and are obviously better than that of the group B from the charge-discharge performance.

In conclusion, under the condition that the coating thickness of the positive/negative electrode active material is the same, compared with the conventional current collector, the discharge capacity and the 1C charge-discharge energy efficiency of the current collector provided by the application can be effectively improved under the multiplying power of 0.33C-3C, the charge-discharge performance of the conventional thin electrode battery is achieved, and the charge-discharge performance of the conventional thin electrode battery is better under the high discharge multiplying power.

The 0.5C/0.5C cycle performance is tested at the temperature of 25 ℃, and the result is shown in FIG. 10, wherein FIG. 10 shows that the capacity retention rate of the B-group battery is reduced rapidly along with the increase of the number of cycles, and the capacity retention rate is 80% when the number of cycles is 461 times; the capacity retention rate of the batteries of the group A and the group C is lower than that of the batteries of the group B along with the increase of the number of cycle turns, and the cycle performance test result of the batteries of the group C is better than that of the batteries of the group A.

Therefore, the B group can enable the battery capacity to be quickly attenuated along with the increase of the cycle number by coating the positive/negative active substances with the conventional current collector in a high thickness, the cycle life of the battery is shortened, and the cycle performance of the battery is not reduced by coating the positive/negative active substances with the current collector 6 times in thickness.

What is not described in this embodiment may be referred to in the relevant description of the rest of the application.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solutions of the present application and not to limit them; although the present application has been described in detail with reference to preferred embodiments, those of ordinary skill in the art will understand that: modifications to the embodiments of the present application or equivalent replacements of some technical features may still be made, which should all be covered by the scope of the technical solution claimed in the present application.

Claims

1. A current collector for a thick electrode, comprising:

an interlayer space configured to accommodate an electrolyte;

2. The current collector for a thick electrode according to claim 1,

the current collecting part comprises a first current collecting part and a second current collecting part, and the first current collecting part and the second current collecting part are separated to form the interlayer space;

3. The current collector for a thick electrode according to claim 2, wherein the first current collecting portion and the second current collecting portion are arranged in parallel with each other.

4. The current collector for a thick electrode according to claim 3, wherein the first current collecting portion and the second current collecting portion are each of a planar structure.

5. The current collector for a thick electrode according to claim 3, wherein the first current collecting portion and the second current collecting portion have a rectangular structure having the same size and shape.

6. The current collector for a thick electrode according to claim 3, wherein the connecting portion is vertically provided on a plane where the first current collecting portion is located.

7. The current collector for the thick electrode according to claim 2 or 3, wherein the connecting portion is at least one of a connecting pillar and a connecting strip.

8. The current collector for a thick electrode according to claim 7, wherein said connecting pillars are uniformly distributed in said interlayer space; and/or

9. The current collector for a thick electrode as claimed in claim 2, wherein the active material providing surface is divided into two non-punching regions and one punching region depending on whether or not through holes are distributed, the punching region being located at a middle portion in a length direction of the current collecting portion, and the punching region being flanked by the non-punching regions.

10. The method of claim 9The current collector for the thick electrode is characterized in that the punching area is a rectangular area, and the length L of the punching area₁1/2-4/5 of the length L of the collecting part.

11. The current collector for the thick electrode according to claim 9, wherein a plurality of said through holes are distributed in a rectangular array in said punching area; the connecting parts are distributed in the interlayer space rectangular array.

12. The current collector for a thick electrode according to claim 11, wherein the through holes and the connecting portions are arranged in a staggered manner in the punching region.

13. The current collector for a thick electrode according to claim 11, wherein the porosity of said current collector is 40-80%.

14. The current collector for a thick electrode according to claim 11, wherein the inner diameter of the through hole ranges from 0.001 mm to 10 mm.

15. The current collector for the thick electrode according to claim 2 or 3, wherein the first current collecting portion and the second current collecting portion are both rigid structures, and the thickness of the first current collecting portion and the thickness of the second current collecting portion are each independently in a range of 0.05-0.5 mm.

16. A current collector for thick electrodes according to any of claims 1 to 3, wherein the height of the interlayer space is in the range of 0.01 to 1 mm.

17. The current collector for the thick electrode according to claim 9 or 11, wherein a leak-proof material layer is compounded on the inner surface of the current collecting portion.

18. The current collector for a thick electrode according to claim 17, wherein said leak-proof layer covers at least said punching area.

19. The current collector for a thick electrode according to claim 2,

when the connecting part is at least partially an electric conductor, the polarity of the active materials arranged on the first current collecting part and the second current collecting part is the same;

20. A battery comprising a current collector as claimed in any one of claims 1 to 19, wherein the thickness of the active material applied to said current collector ranges from 0.1 to 10 mm.

21. The battery of claim 20, wherein the battery is a lithium ion battery.

22. The battery of claim 21, wherein the lithium ion battery is a lithium iron phosphate battery; and/or the battery is a battery for an energy storage system or a power battery for a vehicle.