Secondary battery with electrolyte diffusion promoting function
阅读说明:本技术 一种具有电解液促扩散功能的二次电池 (Secondary battery with electrolyte diffusion promoting function ) 是由 郭永兴 卢林 于 2020-07-27 设计创作,主要内容包括:本发明涉及电池制备技术领域,特别涉及一种具有电解液促扩散功能的二次电池,所述电池包括:电极组件,所述电极组件包括至少两个电极;壳体,所述壳体内部具有容纳电解液的腔体,所述电极组件设置于所述腔体内;电解液促扩散装置,所述电解液促扩散装置能够驱动所述电解液流动。通过本发明提供的一种具有电解液促扩散功能的二次电池,能够解决现有技术中厚电极设计集流体侧电解液中锂离子在正负极之间传输困难的问题以及厚电极带来的局部发热和散热难的问题。(The invention relates to the technical field of battery preparation, in particular to a secondary battery with an electrolyte diffusion promoting function, which comprises: an electrode assembly comprising at least two electrodes; a case having a cavity therein to accommodate an electrolyte, the electrode assembly being disposed within the cavity; electrolyte diffusion promotion means capable of driving the electrolyte to flow. The secondary battery with the electrolyte diffusion promoting function provided by the invention can solve the problems that lithium ions in the electrolyte on the side of a thick electrode design collector are difficult to transmit between a positive electrode and a negative electrode in the prior art and the local heating and heat dissipation caused by the thick electrode are difficult.)
1. A secondary battery having an electrolyte diffusion promoting function, characterized by comprising:
the electrolyte tank comprises a shell, a first electrode and a second electrode, wherein a cavity for accommodating electrolyte is formed in the shell;
the electrode assembly is arranged in the cavity and comprises at least two electrodes, and a gap is formed between every two adjacent electrodes in a separated mode;
electrolyte diffusion promoting device for driving the electrolyte to flow.
2. The secondary battery having an electrolyte diffusion promoting function according to claim 1, wherein the electrolyte diffusion promoting means is provided outside the case;
two ends of the electrolyte diffusion promoting device are respectively communicated with the cavity through pipelines;
the pipes comprise a first pipe and a second pipe;
the first end of the first pipeline is communicated with the outlet end of the electrolyte diffusion promoting device, and the second end of the first pipeline is communicated with the cavity; the first end of the second pipeline is communicated with the cavity, and the second end of the second pipeline is communicated with the inlet end of the electrolyte diffusion promoting device.
3. The secondary battery having an electrolyte diffusion promoting function according to claim 1 or 2, wherein the electrodes are divided into positive electrode plates and negative electrode plates according to the polarity of the surface active material, and the positive electrode plates and the negative electrode plates are stacked in the thickness direction of the electrodes in the cavity in a crossing manner.
4. The secondary battery having an electrolyte diffusion promoting function according to claim 2, wherein the electrode comprises a current collector, and an active material layer containing an active material provided on at least one outer surface of the current collector;
wherein the current collector comprises:
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;
at least one through hole communicated with the interlayer space is formed in the active material arrangement surface, so that lithium ions in the electrolyte can enter the active material through the through hole and/or lithium ions in the active material can enter the electrolyte through the through hole;
the second end of the first pipeline is arranged beside the interlayer space, so that the electrolyte diffusion promoting device can drive the electrolyte in the interlayer space to flow.
5. The secondary battery having an electrolyte diffusion promoting function according to claim 4, wherein the current collecting portion includes:
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;
the interlayer space is provided with at least one connecting part for connecting the first current collecting part and the second current collecting part;
the connecting part comprises a connecting strip, and the connecting strip is arranged at the edge of the interlayer space and encloses the interlayer space, so that the interlayer space is closed in the height direction;
in the electrode assembly, all electrodes are connected in series end to end by adopting short pipes, the short pipes are arranged at the ends of the electrodes in the length direction and are communicated with the interlayer spaces of the electrodes, so that electrolyte in the interlayer spaces of every two adjacent electrodes can flow, and the two short pipes arranged on the same electrode are far away from each other in the length direction of the electrode;
the interlayer space of one tail end electrode in the thickness direction of the electrode assembly is communicated with a second end of a first pipeline, and the second end of the first pipeline is far away from a short pipe arranged on the electrode in the length direction of the electrode; the interlayer space of the electrode at the other end of the electrode assembly in the thickness direction is communicated with the first end of the second pipeline, and the first end of the second pipeline is far away from the short pipe arranged on the electrode in the length direction of the electrode.
6. The secondary battery having an electrolyte diffusion promoting function according to claim 5, wherein when the active material layer of the electrode assembly is parallel to the plane of the bottom of the case, the vertical height of the second end of the first tube is higher than that of the first end of the second tube.
7. The secondary battery having an electrolyte diffusion promoting function according to claim 5 or 6, wherein the active material disposing surface is divided into two non-punched regions and a punched region depending on whether or not through-holes are distributed, the punched region being located at a middle portion in a length direction of the current collecting portion, the punched region being flanked by the non-punched regions; the two ends of the short pipe, the second end of the first pipeline and the first end of the second pipeline are arranged in the non-punching area.
8. The secondary battery with the electrolyte diffusion promoting function according to claim 4, wherein a part of the first pipeline, which is located in the cavity, is communicated with a plurality of branch pipelines, the branch pipelines are mutually connected in parallel and arranged on the first pipeline, the number of the branch pipelines is matched with the number of the electrodes in the electrode assembly, and one ends of the branch pipelines, which are far away from the first pipeline, are arranged beside the interlayer space of the electrodes, so that the electrolyte diffusion promoting device can drive the electrolyte in the interlayer space of the electrodes to flow; the first end of the second pipeline is arranged at the top of the cavity.
9. The secondary battery having an electrolyte diffusion promoting function according to claim 4, wherein the active material layer of the electrode assembly is parallel to the plane of the bottom of the case; or the active material layer of the electrode assembly is perpendicular to the plane of the bottom of the case.
10. The secondary battery having an electrolyte diffusion promoting function according to claim 5, wherein the first current collecting portion and the second current collecting portion 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.
11. The secondary battery having an electrolyte diffusion promoting function according to claim 5, wherein the connecting portion further includes a connecting post;
preferably, the connecting columns are uniformly distributed in the interlayer space.
12. The secondary battery having an electrolyte diffusion promoting function according to any one of claims 1 to 11, wherein the value of the gap is in a range of 0.01 to 1 mm; preferably, the value of the gap ranges from 0.05 mm to 0.5 mm.
13. The secondary battery having an electrolyte diffusion promoting function according to claim 12, further comprising an insulating frame disposed inside the case; and the insulating frame is disposed outside the electrode assembly;
the shape of the insulating frame is matched with that of the electrode assembly, strip-shaped through holes are formed in two opposite surfaces of the insulating frame, at least two electrodes are respectively inserted into the strip-shaped through holes of the insulating frame, and two ends of each electrode are exposed out of the insulating frame.
14. The secondary battery having an electrolyte diffusion promoting function according to claim 13, further comprising a positive electrode bus bar and a negative electrode bus bar;
the bus bar is provided with a first surface and a second surface which are opposite, and the first surface is provided with at least one conductive bar for electrically connecting with the current collecting part of the electrode; the second surface is provided with a convex conducting plate, the conducting plate is perpendicular to the second surface, the conducting plate inserts the lateral wall of casing, just the conducting plate is in the casing stretches out outside and forms positive terminal or negative terminal.
15. The secondary battery having an electrolyte diffusion promoting function as claimed in claim 14, wherein the bus bar is of a rigid structure, and the bus bar is fixedly connected to the current collecting portion so that the electrode assembly and the insulating frame can be fixed inside the case.
16. The secondary battery with the electrolyte diffusion promoting function according to claim 5, wherein the first current collecting part and the second current collecting part are both rigid structures, and the thickness of the first current collecting part and the thickness of the second current collecting part are respectively and independently in a value range of 0.05-0.5 mm;
preferably, the value range of the interlayer space height is 0.01-1 mm.
17. The secondary battery having an electrolyte diffusion promoting function according to claim 4, wherein the thickness of the active material layer has a value in a range of 0.1 to 10 mm;
preferably, the thickness of the positive active material layer ranges from 0.1mm to 0.5 mm; and/or the thickness of the negative active material layer ranges from 0.1mm to 0.4 mm.
18. The secondary battery with electrolyte diffusion promoting function according to any one of claims 1-17, wherein the battery is a lithium ion battery, preferably, the lithium ion battery has a liquid injection coefficient of 5.0-20.0;
more 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.
Technical Field
The invention relates to the technical field of battery preparation, in particular to a secondary battery with an electrolyte diffusion promoting function.
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 lean solution of the monomer cannot realize the internal monitoring and maintenance of the monomer. 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, increasing the thickness of the electrode prolongs the electron and lithium ion transmission path, increases the battery impedance, and has a series of problems such as poor battery rate performance and electrode reaction kinetics, low bonding strength of the electrode coating, and easy falling off.
Transport of lithium ions, comprising 3 parts: 1) the transmission process of lithium ions in the electrolyte, particularly the distribution of lithium ions in the active material on the collector side; 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.
Disclosure of Invention
Based on the above, the invention aims to provide a secondary battery with an electrolyte diffusion promoting function, which can solve the problems that in the prior art, lithium ions in electrolyte on the side of a thick electrode design collector are difficult to transmit between a positive electrode and a negative electrode, and local heating and heat dissipation caused by the thick electrode are difficult.
In order to solve the above technical problems, the present invention provides a secondary battery having an electrolyte diffusion promoting function, the battery including:
the electrolyte tank comprises a shell, a first electrode and a second electrode, wherein a cavity for accommodating electrolyte is formed in the shell;
the electrode assembly is arranged in the cavity and comprises at least two electrodes, and a gap is formed between every two adjacent electrodes in a separated mode;
electrolyte diffusion promoting device for driving the electrolyte to flow.
As an optional technical solution, the electrolyte diffusion promoting device is arranged outside the shell;
two ends of the electrolyte diffusion promoting device are respectively communicated with the cavity through pipelines;
the pipes comprise a first pipe and a second pipe;
the first end of the first pipeline is communicated with the outlet end of the electrolyte diffusion promoting device, and the second end of the first pipeline is communicated with the cavity; the first end of the second pipeline is communicated with the cavity, and the second end of the second pipeline is communicated with the inlet end of the electrolyte diffusion promoting device.
As an optional technical solution, the electrode is divided into a positive electrode plate and a negative electrode plate according to the difference of the polarities of the surface active materials, and the positive electrode plate and the negative electrode plate are stacked in the cavity in a crossed manner along the thickness direction of the electrode.
As an alternative solution, the electrode comprises a current collector and an active material layer containing an active material disposed on at least one outer surface of the current collector;
wherein the current collector comprises:
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;
at least one through hole communicated with the interlayer space is formed in the active material arrangement surface, so that lithium ions in the electrolyte can enter the active material through the through hole and/or lithium ions in the active material can enter the electrolyte through the through hole;
the second end of the first pipeline is arranged beside the interlayer space, so that the electrolyte diffusion promoting device can drive the electrolyte in the interlayer space to flow.
As an optional technical solution, the current collecting part includes:
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;
the interlayer space is provided with at least one connecting part for connecting the first current collecting part and the second current collecting part;
the connecting part comprises a connecting strip, and the connecting strip is arranged at the edge of the interlayer space and encloses the interlayer space, so that the interlayer space is closed in the height direction;
in the electrode assembly, all electrodes are connected in series end to end by adopting short pipes, the short pipes are arranged at the ends of the electrodes in the length direction and are communicated with the interlayer spaces of the electrodes, so that electrolyte in the interlayer spaces of every two adjacent electrodes can flow, and the two short pipes arranged on the same electrode are far away from each other in the length direction of the electrode;
the interlayer space of one tail end electrode in the thickness direction of the electrode assembly is communicated with a second end of a first pipeline, and the second end of the first pipeline is far away from a short pipe arranged on the electrode in the length direction of the electrode; the interlayer space of the electrode at the other end of the electrode assembly in the thickness direction is communicated with the first end of the second pipeline, and the first end of the second pipeline is far away from the short pipe arranged on the electrode in the length direction of the electrode.
As an alternative solution, when the active material layer of the electrode assembly is parallel to the plane of the bottom of the case, the vertical height of the second end of the first tube is higher than that of the first end of the second tube.
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; the two ends of the short pipe, the second end of the first pipeline and the first end of the second pipeline are arranged in the non-punching area.
As an optional technical solution, a part of the first pipe located in the cavity is communicated with a plurality of branch pipes, the branch pipes are mutually connected in parallel and arranged on the first pipe, the number of the branch pipes is matched with the number of the electrodes in the electrode assembly, and one end of each branch pipe, which is far away from the first pipe, is arranged beside an interlayer space of the electrode, so that the electrolyte diffusion promoting device can drive the electrolyte in the electrode interlayer space to flow; the first end of the second pipeline is arranged at the top of the cavity.
As an alternative solution, the active material layer of the electrode assembly is parallel to the plane of the bottom of the case; or the active material layer of the electrode assembly is perpendicular to the plane of the bottom of the case.
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 solution, the connecting portion further includes a connecting pillar;
preferably, the connecting columns are uniformly distributed in the interlayer space.
As an optional technical scheme, the value range of the gap is 0.01-1 mm; preferably, the value of the gap ranges from 0.05 mm to 0.5 mm.
As an optional technical scheme, the device also comprises an insulating frame, wherein the insulating frame is arranged inside the shell; and the insulating frame is disposed outside the electrode assembly;
the shape of the insulating frame is matched with that of the electrode assembly, strip-shaped through holes are formed in two opposite surfaces of the insulating frame, at least two electrodes are respectively inserted into the strip-shaped through holes of the insulating frame, and two ends of each electrode are exposed out of the insulating frame.
As an optional technical scheme, the device also comprises a positive electrode bus bar and a negative electrode bus bar;
the bus bar is provided with a first surface and a second surface which are opposite, and the first surface is provided with at least one conductive bar for electrically connecting with the current collecting part of the electrode; the second surface is provided with a convex conducting plate, the conducting plate is perpendicular to the second surface, the conducting plate inserts the lateral wall of casing, just the conducting plate is in the casing stretches out outside and forms positive terminal or negative terminal.
As an optional technical solution, the bus bar is a rigid structure, and the bus bar is fixedly connected with the current collecting portion, so that the electrode assembly and the insulating frame can be fixed inside the case.
As an optional technical solution, the first current collecting part and the second current collecting part are both rigid structures, and the thickness of the first current collecting part and the thickness of the second current collecting part are independent ranges from 0.05 mm to 0.5 mm;
preferably, the value range of the interlayer space height is 0.01-1 mm.
As an optional technical scheme, the thickness of the active material layer ranges from 0.1mm to 10 mm;
preferably, the thickness of the positive active material layer ranges from 0.1mm to 0.5 mm; and/or the thickness of the negative active material layer ranges from 0.1mm to 0.4 mm.
As an optional technical solution, the battery is a lithium ion battery, preferably, the electrolyte injection coefficient of the lithium ion battery is 5.0-20.0; more 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 invention has the following beneficial effects: the application provides a secondary battery with promote diffusion function of electrolyte, this battery has the promote diffusion equipment of electrolyte, the promote diffusion equipment of this electrolyte can drive the mobile diffusion of electrolyte in the battery chamber, through the diffusion of electrolyte in the drive chamber, can make the local high concentration lithium ion that positive pole/negative pole gathered exchange with other position electrolytes with faster speed, thereby improve the charge-discharge performance of battery, and can effectively distribute the heat between positive pole/negative pole fast and detach, reduce the harm that local overheat brought. Further, in the application, the interlayer space of the positive electrode plate of the battery and the interlayer space of the negative electrode plate of the battery are directly communicated by the connection of the short pipe, the first pipeline and the second pipeline, and under the action of the electrolyte diffusion promoting device, the high-concentration and low-concentration electrolyte contained in the interlayer space of the positive electrode plate and the interlayer space of the negative electrode plate directly performs an exchange action, so that the transmission of lithium ions in the electrolyte on the collector side between the positive electrode and the negative electrode is accelerated. Furthermore, gaps are formed between every two adjacent electrodes, electrolyte can be filled between every two adjacent electrodes through the gaps, the electrolyte can fully infiltrate active materials on the electrodes close to the current collector, and the problems of uneven reaction activity and low capacity exertion of a reaction interface caused by long electrolyte infiltration time and uneven lubrication in the thick electrodes are effectively solved; in addition, the design of electrolyte flowing in the gap can also enable the heat at the central part of the whole container to be rapidly transferred to the edge part of the capacity, and the heat dissipation problem of the large battery cell is effectively improved.
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 an exploded schematic view of a secondary battery having an electrolyte diffusion promoting function according to an embodiment of the present application;
fig. 2 is a schematic structural diagram of an embodiment of a secondary battery having an electrolyte diffusion promoting function provided in the present application;
FIG. 3 is a schematic view of the internal structure of FIG. 2 in a front view direction;
FIG. 4 is a schematic structural diagram of the insulating frame of FIG. 2;
FIG. 5 is a schematic structural diagram of another embodiment of a secondary battery having an electrolyte diffusion promoting function according to the present application;
FIG. 6 is a schematic top view of the internal structure of FIG. 5;
FIG. 7 is a schematic structural diagram of the insulating frame of FIG. 5;
fig. 8 is a schematic structural diagram of another embodiment of a secondary battery having an electrolyte diffusion promoting function provided in the present application;
FIG. 9 is a schematic view of a face of a busbar;
FIG. 10 is a schematic view of another side of the bus bar;
fig. 11 is a schematic structural diagram of a current collector C1 for a thick electrode according to an embodiment of the present disclosure;
fig. 12 is a partial enlarged view of a portion M in fig. 11;
fig. 13 is a schematic half-sectional view of a current collector C1 for a thick electrode according to an embodiment of the present disclosure;
fig. 14 is a schematic view of the connection and via arrangement on the current collector in one embodiment;
fig. 15 is a schematic structural view of a connection portion and a through hole on a current collector arranged in another embodiment;
fig. 16 is a schematic structural view of a connection portion and a through hole on a current collector arranged in another embodiment;
fig. 17 is a schematic structural view of a connection portion and a through hole on a current collector arranged in another embodiment;
fig. 18 is a schematic structural view of a connection portion and a through hole on a current collector arranged in another embodiment;
fig. 19 is a schematic structural diagram of an electrode P1 provided in the present embodiment;
fig. 20 is a schematic structural view of a connection portion and a through hole on a current collector arranged in another embodiment;
FIG. 21 is a graph of cycling performance for batteries of group A, group B and group C;
reference numerals: battery B1, electrode assembly Q1, electrode P1, positive electrode plate P11, negative electrode plate P12,
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 secondary battery with the electrolyte diffusion promoting function adopts the electrolyte
According to fig. 1 to 20, the present application provides a secondary battery having an electrolyte diffusion promoting function, the battery B1 includes a
According to some specific embodiments, in order to facilitate maintenance of the electrolyte
Specifically, the electrolyte
According to other specific embodiments, the electrode assembly Q1 includes at least two electrodes P1, and the electrode P1 is divided into a positive electrode plate P11 and a negative electrode plate P12 according to the polarity of the surface active material thereof, and the positive electrode plate P11 and the negative electrode plate P12 are stacked in the thickness direction of the electrode P1 in the
According to another embodiment provided herein, which relates to the structure of the electrode P1 in the secondary battery with electrolyte diffusion promoting function, the electrode P1 comprises 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; and the thickness of the active material layer 3 ranges from 0.1mm to 10mm, and the thick electrode defined in the application means that the thickness of the active material layer on the electrode is larger than that of a conventional electrode, and more specifically, the thick electrode defined in the application means that the thickness of the active material layer 3 on the electrode is larger than 0.1 mm.
In some preferred embodiments, as shown in fig. 19, 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
Specifically, the current collector C1 in the present application employs an innovative current collector design, which includes an interlayer space 7 configured to accommodate an electrolyte; a header 2, said header 2 having at least one active
Fig. 12 is a partial enlarged view of a portion M in fig. 11, and it can be seen from fig. 12 that the current collecting portion 2 includes a first current collecting portion 21 and a second current collecting portion 22, and the first current collecting portion 21 and the second current collecting portion 22 are separated to form the interlayer space 7; at least one connecting
According to some specific embodiments, in order to enable direct transport exchange of lithium ions in the interlayer space 7 of the positive electrode plate P11 and the interlayer space 7 of the negative electrode plate P12, the schemes are shown in fig. 2-7, the current collector C1 structure is shown in fig. 20, according to fig. 20, the current collector C1 structure is shown, the edge of the interlayer space 7 is provided with a connecting part 23 for connecting the first current collecting part 21 and the second current collecting part 22, the connecting part 23 comprises a connecting bar 232, and the connecting bar 232 is arranged at the edge of the interlayer space 7 and surrounds the interlayer space 7, so that the interlayer space 7 is closed in the height direction; 2-7, wherein, in an electrode assembly Q1, the electrode assembly Q1 is composed of all electrodes P1 connected end to end in series by short tubes 45, the short tubes 45 are arranged at the ends of the electrode P1 in the length direction and communicate with the interlayer space 7 of the electrode P1, so that the electrolyte in the interlayer space 7 of two adjacent electrodes P1 can flow, and two short tubes 45 arranged on the same electrode P1 are arranged away from each other in the length direction of the electrode P1; the interlayer space 7 of the end electrode P1 in the thickness direction of the electrode assembly Q1 communicates with the second end of the first conduit 43, and the second end of the first conduit 43 is away from the short tube 45 provided on the electrode P1 in the length direction of the electrode P1; the electrode P1 at the other end in the thickness direction of the electrode assembly Q1 has its sandwiching space 7 communicating with the first end of the second conduit 44, and the first end of the second conduit 44 is away from the short tube 45 provided on the electrode P1 in the length direction of the electrode P1.
The working principle of the preferred embodiment is illustrated below by taking as an example the charging process of a lithium ion battery, during which Li is charged+The lithium ions are extracted from the positive electrode and are inserted into the negative electrode through the electrolyte, the lithium ions in the electrolyte around the positive electrode are higher than the average value, namely the electrolyte around the interlayer space 7 of the positive electrode plate P11 and the outer surface of the active material layer 3 of the positive electrode is in a lithium-rich state; the lithium ions in the electrolyte around the negative electrode are lower than the average value, that is, the electrolyte around the interlayer space 7 of the negative electrode plate P12 and the outer surface of the active material layer 3 of the negative electrode is in a lithium-deficient state. The distance from lithium ions in the interlayer space 7 of the positive polar plate P11 to the interlayer space 7 of the negative polar plate P12 is longer, and the time for recovering the lithium ion concentration of the electrolyte in the interlayer space 7 of the positive polar plate P11 and the negative polar plate P12 is longer; the interlayer space 7 of the positive electrode plate P11 and the interlayer space 7 of the negative electrode plate P12 are communicated through the short pipe 45, the first pipeline 43 and the second pipeline 44 are used for communicating the electrolyte diffusion promoting device 81 with the interlayer space 7 of the two electrodes P1 at the tail ends of the electrode assembly Q1, after the electrolyte diffusion promoting device 81 is started, high-concentration lithium electrolyte in the interlayer space 7 of the positive electrode plate P11 and low-concentration lithium electrolyte in the interlayer space 7 of the negative electrode plate P12 are in direct contact, the concentrations of the electrolytes in the interlayer spaces 7 of the positive electrode plate P11 and the negative electrode plate P12 are rapidly balanced, the time for restoring balance of the electrolytes in the interlayer spaces 7 of the positive electrode plate P11 and the interlayer space 7 of the negative electrode plate P12 is greatly shortened, and the problem that lithium ions in the electrolytes on the thick electrode collector side of the current collector are difficult to transmit between the positive electrode and the negative electrode is solved.
According to some preferred embodiments, as shown in fig. 2-4, an arrangement mode of the electrode assembly Q1 in the
Fig. 3-7 show another arrangement of the electrode assembly Q1 in the
According to other specific embodiments, as shown in fig. 8, the part of the
The working principle of the preferred embodiment is illustrated below by taking as an example the charging process of a lithium ion battery, during which Li is charged+The lithium ions are extracted from the positive electrode and are inserted into the negative electrode through the electrolyte, the lithium ions in the electrolyte around the positive electrode are higher than the average value, namely the electrolyte around the interlayer space 7 of the positive electrode plate P11 and the outer surface of the active material layer 3 of the positive electrode is in a lithium-rich state; the lithium ions in the electrolyte around the negative electrode are lower than the average value, that is, the electrolyte around the interlayer space 7 of the negative electrode plate P12 and the outer surface of the active material layer 3 of the negative electrode is in a lithium-deficient state. The distance from lithium ions in the interlayer space 7 of the positive polar plate P11 to the interlayer space 7 of the negative polar plate P12 is longer, and the time for recovering the lithium ion concentration of the electrolyte in the interlayer space 7 of the positive polar plate P11 and the negative polar plate P12 is longer; the positive electrode can be driven by the action of the electrolyte diffusion promoter 81The high-concentration lithium ion electrolyte in the interlayer space 7 of the plate P11 is discharged out of the interlayer space 7, the electrolyte around the anode polar plate P11 is supplemented into the interlayer space 7, and when the lithium ion concentration of the electrolyte in the interlayer space 7 of the anode polar plate P11 is rapidly balanced, the heat in the electrolyte is also dissipated. Accordingly, the lithium ion concentration of the low-concentration lithium ion electrolyte in the interlayer space 7 of the negative electrode plate P12 will be balanced quickly.
The structure in current collector C1 to which the present application relates is further described below, and fig. 11-20 illustrate the structure of current collector C1:
in the present application, the
Compared with the conventional current collector in the prior art, the innovative current collector C1 provided by the application has the current collector C1 with the interlayer space 7, when the assembled battery is used, the interlayer space 7 is filled with electrolyte, compared with the poor liquid state of the conventional lithium ion battery, the current collector C1 is in the rich liquid state, the through hole 212 formed in the surface of the current collector C is communicated with the interlayer space 7 in the middle to form a unique lithium ion transport passage, the lithium ion transport distance is reduced by half, taking the first current collector part 21 as an example, after the active material is coated, the lithium ions in the active material on the side of the first current collector part 21 can flow into the electrolyte through the passage between the through hole 212 and the interlayer space 7, the transport distance of the lithium ions in the active material particles can be remarkably shortened by half, the problem of long lithium ion transport path of the active material on the side of the current collector in the conventional art is changed, and the interlayer space 7 is designed, the poor liquid state of the traditional lithium ion battery is changed, the active material can be well soaked, the diffusion speed of lithium ions in the active material is improved, the diffusion speed of the lithium ions in the electrolyte can be improved by arranging the electrolyte diffusion promoting device, and on the basis, the design of a thick electrode of the battery can be realized.
According to an embodiment of the present application, as shown in fig. 20, on the active
As a specific embodiment, in order to facilitate mass production of the current collector C1 and subsequent arrangement of active materials, fig. 11 to 12 of the present application illustrate a current collector C1 in which 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
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 material of the first current collecting portion 21 and the second current collecting portion 22 is not particularly limited as long as it does not cause chemical changes in a manufactured secondary battery having an electrolyte diffusion promoting function and has high conductivity, and when it is used as a positive electrode current collector, the material may be 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
The structure of the
The following description is made with reference to fig. 14-18 and 20, respectively: as a specific embodiment, as shown in fig. 14 or 15, the connecting
As will be described in detail below, the arrangement of the through
The through
As a specific embodiment, in fig. 14-15, a plurality of the through
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
When the inner diameter of the through
As a preferred embodiment, as shown in fig. 19, the inner surface of the punched
According to some embodiments, as shown in fig. 3, 6 or 8, the
Preferably, the height of the
In order to facilitate the installation of the electrode assembly Q1 and control the height of the
In order to collect the current of the positive electrode plate P11 and the negative electrode plate P12, the battery further comprises a positive electrode bus bar 63-1 and a negative electrode bus bar 63-2; as shown in fig. 9-10, the bus bar 63 has a
In a preferred embodiment, the bus bar 63 is of a rigid structure, and the
The secondary battery structure with the electrolyte diffusion promoting function is very suitable for being used as a lithium ion battery, and the battery structure is particularly suitable for the lithium ion battery with the electrolyte injection coefficient of 5.0-20.0; 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.
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-
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
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.