CN116230945B

CN116230945B - Pole piece, preparation method and application thereof

Info

Publication number: CN116230945B
Application number: CN202310501818.0A
Authority: CN
Inventors: 韩承均; 吴桂森; 段晓勇; 王海燕; 李伟
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2023-05-06
Filing date: 2023-05-06
Publication date: 2023-09-15
Anticipated expiration: 2043-05-06
Also published as: CN116230945A

Abstract

The application relates to the field of batteries, in particular to a pole piece, a preparation method and application thereof. The pole piece includes an active layer including a conduit material including a first conduit that generates a capillary force to an electrolyte in contact with the pole piece. According to the application, the conduit material is doped in the active layer, and the first conduit in the conduit material has a hollow structure, so that a capillary tube can be formed, and capillary force is generated on electrolyte contacted with the pole piece. After the pole piece is contacted with electrolyte, the electrolyte enters the first conduit from at least one pipe end of the first conduit on the surface of the pole piece and is rapidly drained to a deeper part of the pole piece from the surface of the pole piece under the capillary action of the first conduit, so that the infiltration rate of the electrolyte in the pole piece is accelerated, the infiltration of the pole piece is greatly improved, and the complete infiltration of the pole piece is realized.

Description

Pole piece, preparation method and application thereof

Technical Field

The application relates to the field of batteries, in particular to a pole piece, a preparation method and application thereof.

Background

With the rapid increase in the demand of secondary batteries in the market, great challenges are presented to battery productivity. The cell is the smallest unit of a battery system, and the production of the cell comprises the steps of anode homogenization, cathode homogenization, coating, rolling, slitting, baking, winding, shell entering, spot welding, baking, liquid injection and other various procedures. The electrolyte injection method comprises the steps of placing a battery cell assembly into a special electrolyte injection machine, and automatically injecting electrolyte into the battery cell assembly through the electrolyte injection machine.

In actual production, the electrolyte has a slow infiltration rate on the polar plates, so that the required time is long, the production efficiency of the battery cell is limited, and the productivity of the battery cell is seriously affected.

Disclosure of Invention

In view of the problems, the application provides a pole piece, a preparation method and application thereof, which can relieve the problem of slow infiltration rate of electrolyte to the pole piece in the production process of an electric core.

In a first aspect, the present application provides a pole piece comprising an active layer comprising a conduit material comprising a first conduit that generates a capillary force to an electrolyte in contact with the pole piece.

According to the embodiment of the application, the conduit material is doped in the active layer, and the first conduit in the conduit material is of a hollow structure, so that a capillary tube can be formed, and capillary force is generated on electrolyte contacted with the pole piece. After the pole piece is contacted with electrolyte, the electrolyte enters the first conduit from at least one pipe end of the first conduit on the surface of the pole piece, and is rapidly drained to a deeper part of the pole piece from the surface of the pole piece under the capillary action of the first conduit, so that the infiltration rate of the electrolyte in the pole piece is accelerated, the infiltration of the pole piece is greatly improved, and the complete infiltration of the pole piece is realized.

In some embodiments, the interior of the first conduit has one or more continuous channels.

In case there is only one continuous channel inside the first conduit, the first conduit is also a single channel conduit. Under the condition of more than one continuous channel, the increase of the channels is beneficial to improving capillary action and further accelerating the infiltration speed of electrolyte in the pole piece; and under the condition that the extending directions of any two continuous channels are different, electrolyte can be siphoned in different directions, so that the electrolyte can infiltrate the polar plates in different directions.

In some embodiments, the catheter material further comprises a second catheter having an inner diameter that is smaller than the inner diameter of the first catheter; the first conduit encloses one or more of the second conduits. After the second guide pipe is added in the guide pipe material, the number of channels can be increased, the guide pipe material with a plurality of channels is formed, the increase of the channels is beneficial to improving capillary action, and the infiltration speed of electrolyte in the pole piece is further accelerated.

In some embodiments, the axial direction of the second conduit forms an angle with the axial direction of the first conduit of less than 90 °. The axial direction of the duct means the extending direction of the duct, and in the case where the duct is in a straight shape, the axial direction of the duct is the center line direction of the duct; for the case where the catheter is curved or there is a curve, the axial direction of the catheter is different at each location, and the axial direction at any one location can be understood as the direction of the circumscribed line of the curve at that location. The axial direction of the second conduit and the axial direction of the first conduit form an angle smaller than 90 degrees, so that any pipe end of the second conduit is not perpendicular to the pipe wall of the first conduit, namely, the pipe end of the second conduit is not blocked by the pipe wall of the first conduit, and a communicated channel is formed, so that drainage effect can be effectively exerted.

In some embodiments, the first conduit has an inner diameter of 50-1000 nm; in other embodiments, the first conduit has an inner diameter of 200-500 nm. Generally, within a certain range, the smaller the tube diameter, the greater the capillary force; the greater the capillary force, the greater the capillary rise. However, the smaller the pipe diameter is, the more difficult the manufacturing is. The first conduit in the conduit material provided by the embodiment of the application has a proper inner diameter, and can well provide capillary force for the transmission of electrolyte; while such a first conduit is easy to manufacture.

In some embodiments, the second conduit has an inner diameter of 10-500 nm; in other embodiments, the second conduit has an inner diameter of 10-250 nm. The second conduit in the conduit material provided by the embodiment of the application has a proper inner diameter, and can provide capillary force for the transmission of electrolyte.

In some embodiments, the first conduit has an outer diameter of 50-1100 nm; in other embodiments, the first conduit has an outer diameter of 50-200 nm. The first catheter of the embodiment of the application has a proper outer diameter, so that the catheter material can be well dispersed in the active layer, and the dispersibility of other components in the active layer is not adversely affected after the catheter material is doped into the active layer.

In some embodiments, the length of the first conduit is 200-10 ⁸ nm; in other embodiments, the first guideThe length of the tube is 10 ³ ~10 ⁵ nm. The first guide pipe has longer length, can carry out long distance transmission to the electrolyte for the inside electrolyte infiltration rate of pole piece promotes pole piece infiltration by a wide margin.

In some embodiments, the second conduit has a length of 10-10 ⁸ nm; in other embodiments, the second conduit has a length of 10 ³ ~10 ⁵ nm. Similarly to the first conduit, the second conduit also has a longer length, and the length of the second conduit can be the same as that of the first conduit or different from that of the first conduit (shorter or longer than that of the first conduit), so that the electrolyte can be transmitted for a long distance, the electrolyte infiltration rate inside the pole piece is quickened, and the pole piece infiltration is greatly improved.

In some embodiments, the catheter material contains an electrophilic functional group. The electrolyte-philic functional group refers to a functional group which has a large affinity to an electrolyte and can attract electrolyte molecules. In lithium ion batteries, the electrolyte generally contains carbonyl, methyl, methoxy and other functional groups, and then the electrolyte-philic functional groups can be selected to have similar polarity to those in the electrolyte, or to have the same functional groups as the electrolyte, so that the infiltration rate of the electrolyte is accelerated according to a similar compatibility principle, and the infiltration of the electrolyte in the pole piece is guided.

In some embodiments, the electrolyte-philic functional groups include, but are not limited to, C-N bonds, carbonyl groups, C _1~3 One or more of alkyl, methoxy, ethoxy, carboxyl, ester groups. Wherein C is _1~3 Alkyl refers to alkyl containing 1-3 carbon atoms, including methyl, ethyl and propyl; the ester group is-COO-. The functional group has good affinity with common lithium ion battery electrolyte, and can accelerate the infiltration rate of the electrolyte in the pole piece.

In some embodiments, the electrolyte-philic functional groups are distributed on the surface of any one or more of the inner wall of the first conduit, the outer wall of the first conduit, the inner wall of the second conduit, and the outer wall of the second conduit. Specifically, in the case that the catheter material only comprises the first catheter, the electrophilic functional groups are distributed on the surface of any one or more of the inner wall of the first catheter and the outer wall of the first catheter; in the case where the catheter material further includes a second catheter, the electrophilic functional groups are distributed on the surface of any one or more of the inner wall of the first catheter, the outer wall of the first catheter, the inner wall of the second catheter, and the outer wall of the second catheter. The electrolyte-philic functional groups can be distributed on any surface of the catheter material, and have different lifting effects on the infiltration rate of the electrolyte under different distribution conditions.

In some embodiments, the mass content of the electrolyte-philic functional group on the catheter material is 0.01% -30%; in other embodiments, the electrolyte-philic functional group is present on the catheter material in an amount of 10% -20% by mass. Under proper mass content, the electrolyte-philic functional group can accelerate the infiltration rate of electrolyte, guide the infiltration of the electrolyte in the pole piece, and simultaneously not cause blockage to the channel in the catheter material.

In some embodiments, the catheter material has a mass content in the active layer of 0.01% -3%; in other embodiments, the catheter material is present in the active layer in an amount of 0.05% -2% by mass. Proper amount of conduit material is doped in the active layer, so that the wettability of the pole piece can be effectively improved, and more energy density of the battery cell can not be lost.

In a second aspect, the application provides a method for preparing a pole piece, comprising the following steps: providing an electrode slurry comprising a catheter material; coating the electrode slurry; the conduit material includes a first conduit that generates a capillary force to an electrolyte in contact with the pole piece.

The pole piece preparation method provided by the embodiment of the application can adopt a general preparation method of the pole piece, namely, the pole piece is prepared by pulping and coating, and the prepared pole piece contains a conduit material, so that the infiltration rate of electrolyte in the pole piece can be accelerated, the wettability of the pole piece is greatly improved, and the complete infiltration of the pole piece is facilitated.

In a third aspect, the application provides a battery cell, which comprises the pole piece or the pole piece prepared by the method.

The battery monomer of the embodiment of the application comprises the pole piece, wherein the pole piece can be either a positive pole piece or a negative pole piece, or both the positive pole piece and the negative pole piece. Because the electrode plate of the battery monomer is doped with a special conduit material, the infiltration rate of the electrolyte to the electrode plate can be quickly improved, and the electrolyte can fully infiltrate the whole electrode plate, so that the battery monomer has good electrochemical performance.

In a fourth aspect, the present application provides a battery comprising the above-described battery cell.

The battery in the embodiment of the application comprises the battery monomer, and the electrode plate of the battery monomer is doped with the special conduit material, so that the infiltration rate of the electrolyte to the electrode plate can be rapidly improved, and the electrolyte can fully infiltrate the whole electrode plate, so that the battery comprising the battery monomer also has good electrochemical performance.

In a fifth aspect, the present application also provides an electric device, which includes the above battery. The battery is used for providing electric energy.

The foregoing description is only an overview of the present application, and is intended to be implemented in accordance with the teachings of the present application in order that the same may be more clearly understood and to make the same and other objects, features and advantages of the present application more readily apparent.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the application. Also, like reference numerals are used to designate like parts throughout the accompanying drawings. In the drawings:

FIG. 1 is a schematic illustration of electrolyte infiltration after a conventional pole piece is contacted with the electrolyte;

FIG. 2 is a schematic illustration of the wetting of an electrolyte after a pole piece incorporating a catheter material provided in an embodiment of the present application is contacted with the electrolyte;

FIG. 3 is a schematic diagram of two cross-sectional shapes [ (a) of a first conduit in the conduit material according to an embodiment of the present application ₁ ) Drawing and (a) ₂ ) Drawing of the figure]And the first conduit wraps the second conduit in a cross-sectional structure schematic [ (b) and (c)]；

Fig. 4 is a schematic structural diagram of a bare cell and a battery cell;

FIG. 5 is a schematic view showing the structure of the catheter material in example 1 of the present application;

FIG. 6 is a graph of the results of the climbing liquid test of the pole piece provided in example 1 of the present application and the pole piece provided in comparative example 1;

FIG. 7 is a graph showing the results of the wet-out rate test for the pole piece provided in example 1 of the present application and the pole piece provided in comparative example 1;

reference numerals:

10-pole piece, 20-electrolyte, 30-catheter material, 31-first catheter, 32-second catheter.

Detailed Description

Embodiments of the technical scheme of the present application will be described in detail below with reference to the accompanying drawings. The following examples are only for more clearly illustrating the technical aspects of the present application, and thus are merely examples, and are not intended to limit the scope of the present application.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having" and any variations thereof in the description of the application and the claims and the description of the drawings above are intended to cover a non-exclusive inclusion.

In the description of embodiments of the present application, the technical terms "first," "second," and the like are used merely to distinguish between different objects and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated, a particular order or a primary or secondary relationship. In the description of the embodiments of the present application, the meaning of "plurality" is two or more unless explicitly defined otherwise.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.

In the description of the embodiments of the present application, the term "and/or" is merely an association relationship describing an association object, and indicates that three relationships may exist, for example, a and/or B may indicate: a exists alone, A and B exist together, and B exists alone. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.

In the description of embodiments of the application, the term "at least one" means one or more, and "a plurality" means two or more. "at least one of" or the like means any combination of these items, including any combination of single item(s) or plural items(s). For example, "at least one (individual) of a, b, or c," or "at least one (individual) of a, b, and c," may each represent: a, b, c, a-b (i.e., a and b), a-c, b-c, or a-b-c, wherein a, b, c may be single or multiple, respectively.

It should be understood that, in various embodiments of the present application, the sequence number of each process described above does not mean that the execution sequence of some or all of the steps may be executed in parallel or executed sequentially, and the execution sequence of each process should be determined by its functions and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

The weights of the relevant components mentioned in the description of the embodiments of the present application may refer not only to the specific contents of the components, but also to the proportional relationship between the weights of the components, so long as the contents of the relevant components in the description of the embodiments of the present application are scaled up or down within the scope of the disclosure of the embodiments of the present application. Specifically, the mass described in the description of the embodiment of the application may be a mass unit known in the chemical industry field such as [ mu ] g, mg, g, kg.

The battery unit is the minimum unit of the battery system, a plurality of battery units form a module, and a plurality of modules form a battery pack. The production of the battery core comprises the working procedures of anode homogenization, coating, rolling, slitting, baking, winding, shell entering, spot welding, baking, liquid injection, cap welding, cleaning, drying and storing, alignment degree detection, shell code spraying, formation, OCV (open circuit voltage) measurement, normal-temperature storage, capacity division and the like. The electrolyte injection method comprises the steps of placing a battery cell assembly into a special electrolyte injection machine, and automatically injecting electrolyte into the battery cell assembly through the electrolyte injection machine.

In the process of injecting the electrolyte, as shown in fig. 1, after the electrolyte is injected into the cell assembly, the pole piece 10 (a) in fig. 1) is contacted with the electrolyte 20, the electrolyte 20 is gradually infiltrated into the pole piece 10, b) in fig. 1, the infiltration time is long, and the problem of incomplete infiltration exists, see c) in fig. 1, d) the blank of the graph (c) in fig. 1, d) the white area in the circle in the graph). Therefore, in actual production, high-temperature standing is needed after the battery cell is injected, namely, long time is spent at high temperature to fully infiltrate the pole piece. For example, the hard shell cell with the model of 124AH is injected for 10min, and the high-temperature standing time after injection is up to 10+/-2 h. At this time, the growing up greatly limits the production efficiency of the battery cell and seriously affects the productivity of the battery cell.

In order to enable the electrolyte to fully infiltrate the pole piece in a short time, the related technology uses at least one groove in the active layer of the pole piece as an infiltration channel of the electrolyte to the active layer so as to increase the contact area between the active layer and the electrolyte, so that the electrolyte fully infiltrates the active layer in a short time, the risk of bridge breaking of the electrolyte is reduced, and the cycle life of the electrochemical device is improved. According to the research, in the technology, as the grooves are formed in the active layer, the weight and the surface density of the active material in the pole piece can be reduced, and the energy density of the battery cell is affected. In addition, the infiltration rate of the pole piece is mainly limited by infiltration of the inside of the pole piece and between active material particles, and the method has no effect of improving the infiltration path, so that the infiltration rate is limited. In addition, from the safety and reliability angle, grooves with different depths are formed in the active layer, the pole piece expands to generate larger expansion force in the cell circulation process, when the pole piece current collector side is subjected to larger pressure, the upper part is not bound by the same force, the active material has risks of breakage and demoulding, and the cycle life is further reduced, and even the safety risk of the current collector is short-circuited.

Meanwhile, many studies have been made on the improvement of the infiltration rate of the electrolyte by incorporating a porous material, such as porous carbon, into the active layer of the electrode sheet and using the abundant pores of the porous material to absorb and preserve the electrolyte. However, the pores in these porous materials generally have the problem of short paths, the effect on the electrolyte is only local, the effect of improving the electrolyte infiltration speed is limited as a whole, and particularly, the infiltration on the pole piece height is difficult to realize rapidly.

According to the embodiment of the application, the material with the conduit structure is doped in the pole piece, and the conduit structure in the material can form a capillary tube to provide capillary force for infiltration of electrolyte and carry out long-distance transmission on the electrolyte. Therefore, the capillary force of the guide pipe in the material is utilized for drainage, so that the electrolyte infiltration rate inside the pole piece can be accelerated, and the pole piece infiltration is greatly improved.

The application is further illustrated by the following examples. It is to be understood that these examples are illustrative of the present application and are not intended to limit the scope of the present application.

According to a first aspect of embodiments of the present application there is provided a pole piece comprising an active layer, the active layer comprising a conduit material comprising a first conduit that generates a capillary force to an electrolyte in contact with the pole piece.

The active layer is used as a medium for transferring electrons in the chemical reaction process of the battery in the pole piece, and the active layer mainly participates in the chemical reaction of the battery through the active material. The term "conduit" refers to a tubular structure having a continuous passageway with a hollow structure (an externally shelled, internally hollow structure) inside and at least two tubular ends from which fluid can flow out after entering the conduit from one tubular end.

According to the embodiment of the application, the conduit material is doped in the active layer, and the first conduit in the conduit material is of a hollow structure, so that a capillary tube can be formed, and capillary force is generated on electrolyte contacted with the pole piece. As shown in fig. 2, when the pole piece 10[ see a) in fig. 2 ] is contacted with the electrolyte 20, the electrolyte 20 enters the interior of the first conduit from at least one pipe end of the first conduit of the conduit material 30, which is positioned on the surface of the pole piece 10, and is rapidly siphoned from the surface of the pole piece to deeper depths of the pole piece under the capillary force of the first conduit; in the embodiment of the application, since the catheter material is dispersed in the active layer and can extend along all directions, the electrolyte can be siphoned to all places including the high-place area in the interior, such as the b) diagram and the c) diagram in fig. 2, so that the infiltration rate of the electrolyte in the pole piece 10 is accelerated, the pole piece infiltration is greatly improved, and the complete infiltration of the pole piece 10 is facilitated.

In case there is only one continuous channel inside the first conduit, the first conduit is also a single channel conduit.

In the case where the first duct has one or more continuous passages inside, that is, the first duct is a duct having a plurality of passages, the extending directions of any two continuous passages may be the same or different. Wherein, in the case that the extending directions of any two continuous channels are the same, the continuous channels have openings in the same direction. In case there is a difference in the extending direction of any two consecutive channels, these consecutive channels have openings of different directions. For example, in the case where there is a difference in the extending directions of any two continuous passages, the cross-sectional shape of the first conduit can be seen in (a) of fig. 3 ₁ ) Drawing and (a) ₂ ) A figure, wherein (a) ₁ ) The figure shows that the interior of the first conduit has two consecutive channels of different extension direction, (a) ₂ ) The figure shows that the interior of the first conduit has five extending directions which are mutually differentIs provided. In the case where there are any two continuous channels extending in different directions, the cross-sectional shape of the first conduit is not limited to (a) of fig. 3 ₁ ) Drawing and (a) ₂ ) The figure may also be other various situations. Under the condition of more than one continuous channel, the increase of the channels is beneficial to improving capillary action and further accelerating the infiltration speed of electrolyte in the pole piece; and under the condition that the extending directions of any two continuous channels are different, electrolyte can be siphoned in different directions, so that the electrolyte can infiltrate the polar plates in different directions.

In some embodiments, the catheter material further comprises a second catheter having an inner diameter that is smaller than the inner diameter of the first catheter; the first conduit encloses one or more second conduits. The term "package" means enclosed. The first conduit enveloping the one or more second conduits means that the one or more second conduits are contained within the interior of the first conduit, any of which may be located in at least one of the walls, channels, of the first conduit. The schematic cross-sectional structure of the first conduit wrapping the second conduit is shown in fig. 3 (b) and (c). In fig. 3 (b) and (c), 31 denotes a first duct, 32 denotes a second duct enclosed in the first duct 31, black filled areas in fig. 3 (b) and (c) denote the walls of the first duct 31 or the walls of the second duct 32, and blank areas denote channels. In fig. 3 (b), two second ducts 32 are located in the passage of the first duct 31; in fig. 3 (c), a part of the second conduit 32 is located in the passage of the first conduit 31, and a part of the second conduit 32 is located on the wall of the first conduit 31. After the second guide pipe is added in the guide pipe material, the number of channels can be increased, the guide pipe material with a plurality of channels is formed, the increase of the channels is beneficial to improving capillary action, and the infiltration speed of electrolyte in the pole piece is further accelerated.

In some embodiments, the axial direction of the second conduit forms an angle of less than 90 ° with the axial direction of the first conduit. The axial direction of the duct means the extending direction of the duct, and in the case where the duct is in a straight shape, the axial direction of the duct is the center line direction of the duct; for the case where the catheter is curved or there is a curve, the axial direction of the catheter is different at each location, and the axial direction at any one location can be understood as the direction of the circumscribed line of the curve at that location. The axial direction of the second conduit is parallel to the axial direction of the first conduit to form an angle smaller than 90 degrees, so that any pipe end opening of the second conduit is not perpendicular to the pipe wall of the first conduit, namely, the pipe end opening of the second conduit is not blocked by the pipe wall of the first conduit, a smooth channel is provided, and a drainage function can be effectively exerted.

In some embodiments, the second conduit has an inner diameter of 10-500 nm; in other embodiments, the second conduit has an inner diameter of 10 to 250nm; in other embodiments, the second conduit has an inner diameter of 10 to 50nm. The second conduit in the conduit material provided by the embodiment of the application has a proper inner diameter, and can provide capillary force for the transmission of electrolyte.

In some embodiments, the length of the first conduit is 200-10 ⁸ nm; in other embodiments, the first conduit has a length of 10 ³ ~10 ⁵ nm. The first guide pipe has longer length, can carry out long distance transmission to the electrolyte for the inside electrolyte infiltration rate of pole piece promotes pole piece infiltration by a wide margin.

In some embodiments, the firstThe length of the two guide pipes is 10-10 ⁸ nm; in other embodiments, the second conduit has a length of 10 ³ ~10 ⁵ nm. Similarly to the first conduit, the second conduit also has a longer length, and the length of the second conduit can be the same as that of the first conduit or different from that of the first conduit (shorter or longer than that of the first conduit), so that the electrolyte can be transmitted for a long distance, the electrolyte infiltration rate inside the pole piece is quickened, and the pole piece infiltration is greatly improved.

In some embodiments, the catheter material contains an electrolyte-philic functional group. The electrolyte-philic functional group refers to a functional group which has a large affinity to an electrolyte and can attract electrolyte molecules. In lithium ion batteries, the electrolyte generally contains carbonyl, methyl, methoxy and other functional groups, and then the electrolyte-philic functional groups can be selected to have similar polarity to those in the electrolyte, or to have the same functional groups as the electrolyte, so that the infiltration rate of the electrolyte is accelerated according to a similar compatibility principle, and the infiltration of the electrolyte in the pole piece is guided.

In some embodiments, the electrolyte-philic functional groups are distributed on the surface of any one or more of the inner wall of the first conduit, the outer wall of the first conduit, the inner wall of the second conduit, and the outer wall of the second conduit. Specifically, in the case that the catheter material comprises only the first catheter, the electrophilic functional groups are distributed on the surface of any one or more of the inner wall of the first catheter and the outer wall of the first catheter; in the case where the catheter material further includes a second catheter, the electrophilic functional groups are distributed on the surface of any one or more of the inner wall of the first catheter, the outer wall of the first catheter, the inner wall of the second catheter, and the outer wall of the second catheter. The electrolyte-philic functional groups can be distributed on any surface of the catheter material, and have different lifting effects on the infiltration rate of the electrolyte under different distribution conditions.

Illustratively, the electrophilic functional groups may include, but are not limited to, the following distribution scenarios:

1) The electrolyte-philic functional groups are simultaneously distributed on the inner wall surface of the first conduit, the outer wall surface of the first conduit, the inner wall surface of the second conduit, and the outer wall surface of the second conduit. In this case, on the one hand, the electrolyte can quickly infiltrate the inner wall surface of the first conduit, the inner wall surface of the second conduit and the outer wall surface of the second conduit (the outer wall of the second conduit is positioned inside the first conduit), so that the electrolyte is guided to the inside/deep of the pole piece through the internal channels of the first conduit and the second conduit, and the infiltration of the electrolyte to the pole piece is promoted; on the other hand, the electrolyte can quickly infiltrate the outer wall surface of the first guide pipe, and infiltrates into the inside/deep part of the pole piece along the outer wall of the first guide pipe, so that the infiltration of the electrolyte to the pole piece is further promoted. Thus, in the case where the electrophilic functional groups have the same distribution area density (in the embodiment of the present application, the distribution area density of the electrophilic functional groups means the content of the electrophilic functional groups per unit area in the surface on which the electrophilic functional groups are distributed), this distribution has a very fast electrolyte infiltration rate.

2) The electrolyte-philic functional groups are distributed on the inner wall surface of the first conduit and the inner wall surface of the second conduit simultaneously. Under the condition, the electrolyte can quickly infiltrate the inner wall surface of the first conduit and the inner wall surface of the second conduit, so that the electrolyte is drained to the inside/deep part of the pole piece by the first conduit and the second conduit, and finally, the quick infiltration of the electrolyte to the pole piece is realized. In the case where the electrophilic functional groups have the same distribution area density, the infiltration rate of the electrolyte is reduced due to the lack of the outer wall surface of the second conduit and the electrophilic functional groups of the outer wall surface of the first conduit, as compared with the case of the 1) distribution.

3) The electrophilic functional groups are distributed only on the inner wall surface of the first conduit, or the electrophilic functional groups are distributed only on the inner wall surface of the second conduit. In this case, the rate of penetration of the electrolyte can still be increased by these electrolyte-philic functional groups, but in the case of electrolyte-philic functional groups having the same areal density of distribution, this is reduced compared to the cases 1), 2).

4) The electrophilic functional groups are distributed only on the outer wall surface of the first conduit, or the electrophilic functional groups are distributed only on the outer wall surface of the second conduit, or the electrophilic functional groups are distributed on the outer wall surface of the first conduit and the outer wall surface of the second conduit at the same time. In this case, the electrolyte is subjected to little affinity in the internal channels of the catheter material or is not in contact with any of the electrolyte-philic functional groups in the internal channels of the catheter material, and the rate of infiltration is reduced, but improved over the case where the catheter material does not have any electrolyte-philic functional groups.

In some embodiments, the electrophilic functional group is derived from the bulk material of the catheter material, and/or the electrophilic functional group is modified at the surface of the catheter material. The body material of the catheter material refers to the composition of the substances constituting the catheter material. The surface of the conduit material includes a surface of any one or more of an inner wall of the first conduit, an outer wall of the first conduit, an inner wall of the second conduit, and an outer wall of the second conduit. In the embodiment of the application, the electrolyte-philic functional group can be a functional group of the body material, which exists when the catheter material is formed, or can be introduced to the catheter material for surface modification after the catheter material is formed, so that the catheter material has various forms.

In some embodiments, the mass content of the electrolyte-philic functional groups on the catheter material is 0.01% -30%; in other embodiments, the mass content of the electrolyte-philic functional groups on the catheter material is 10% -20%. Under proper mass content, the electrolyte-philic functional group can accelerate the infiltration rate of electrolyte, guide the infiltration of the electrolyte in the pole piece, and simultaneously not cause blockage to the channel in the catheter material.

In some embodiments, the catheter material is present in the active layer in an amount of 0.01% -3% by mass; in other embodiments, the catheter material is present in the active layer in an amount of 0.05% -2% by mass. For example, the catheter material may be present in the active layer in an amount of 0.01%,0.02%,0.05%,0.1%,0.15%,0.2%,0.25%,3%, etc. Proper amount of conduit material is doped in the active layer, so that the wettability of the pole piece can be effectively improved, and more energy density of the battery cell can not be lost.

In some embodiments, the bulk material of the catheter material comprises any one or more of natural polymeric materials, synthetic polymeric materials. Natural polymeric materials refer to high molecular weight compounds found in animals, plants and other organisms. Exemplary natural polymeric materials include, but are not limited to, one or more of chitosan, silk fibroin, collagen, hyaluronic acid, gelatin. The synthetic polymer material is a high molecular weight compound which is not in animals, plants and other organisms and is synthesized by a certain method manually. Exemplary synthetic polymeric materials include, but are not limited to, one or more of silicone, polyethylene, copolymers of hydroxyethyl methacrylate and methyl methacrylate, polyvinyl alcohol, polyaniline, and polypyrrole, wherein polyaniline, polypyrrole has some conductivity and also can act to improve the conductivity of the pole piece. As a catheter material incorporated into the active layer of a pole piece, it is desirable to have one or more of the attributes of being stable, insoluble, having a certain tensile strength and toughness, and having good electrical conductivity, to meet the operational requirements of the pole piece. The natural polymer material and the synthetic polymer material have good stability, tensile strength and toughness, can meet the requirements of the pole piece, and part of the materials also have conductivity and can be used as materials for manufacturing catheter materials. Meanwhile, part of the body material can also provide electrolyte-philic functional groups.

In some embodiments, the bulk material of the catheter material further comprises a conductive inorganic material, such as carbon nanotubes, graphene. The conductive inorganic material is mixed with the polymer material, so that the catheter material can be endowed with good conductivity.

In some embodiments, the method of making the catheter material includes one or more of 3D printing, electrospinning, braiding, and templating. In the embodiment of the application, various methods which are available in the art and can form a catheter structure can be used for processing the body material of the catheter material to form the catheter material with a required structure, such as 3D printing, electrostatic spinning, braiding, template crimping and the like. Wherein 3D printing is an additive manufacturing method, and a 3D printer is used to build a desired structure by printing ink containing bulk materials of catheter materials layer by layer. Electrospinning is generally performed by preparing a bulk material of a catheter material into a solution or melt, and performing jet spinning in a strong electric field to form filaments. The material with the conduit structure can be formed by controlling the spraying mode, or controlling the shape and/or the movement state of the receiving device, or controlling the shape and/or the movement state of the spraying device during the electrostatic spinning process. Alternatively, the fiber film may be formed after electrospinning, and the duct structure may be formed by braiding and/or crimping the fiber film. The braiding method is to form a material with a conduit structure by mutually interlacing or hooking the slender body materials. The template method is to pour the solution or melt containing the bulk material into a specific template, and finally fix and mold the solution or melt to obtain the catheter material. In the embodiment of the application, in the preparation process of the catheter material, one processing method can be adopted alone, and a plurality of processing methods can be combined for use.

In some embodiments, the active layer further comprises an active material. The active material is the main substance participating in the chemical reaction of the battery. In an embodiment of the present application, the active material in the active layer includes at least one of a positive electrode active material and a negative electrode active material. In embodiments of the present application, exemplary positive electrode active materials include, but are not limited to, one or more of lithium iron phosphate, lithium manganese iron phosphate, lithium cobalt oxide, lithium manganate, lithium nickel cobalt aluminate; exemplary negative electrode active materials include, but are not limited to, one or more of natural graphite, artificial graphite, mesophase micro carbon spheres (MCMB), hard carbon, soft carbon, silicon-carbon composites. The mass content of the active material in the active layer may be 50% -99%, for example 60% -95%, for example 80% -95%, etc.

In some embodiments, the active layer further comprises a conductive agent. The conductive agent collects micro-current among the components of the pole piece, and improves the electronic conductivity. Exemplary conductive agents are acetylene black (SP), carbon nanotubes, conductive carbon black (super-P), ketjen black, carbon fibers, graphene, and the like. The mass content of the conductive agent in the active layer may be 0.5% to 10%, and further, for example, 1% to 5%.

In some embodiments, the active layer further comprises a binder. The adhesive is used for improving the bonding capability between the components of the pole piece. Exemplary binders include one or more of Styrene Butadiene Rubber (SBR), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyvinyl butyral (PVB), aqueous acrylic resin (water-based acrylic resin), and carboxymethyl cellulose (CMC).

In some embodiments, the active layer further optionally includes a thickener, such as carboxymethyl cellulose (CMC). The mass content of the thickener in the active layer is 0.05% -3%, and is 0.2% -1% for example.

In some embodiments, the pole piece further comprises a current collector that is coupled to the active layer. In some embodiments, the active layer is attached to both surfaces of the current collector. The current collector on the pole piece is used to combine with the active layer and transport electrons in the cell chemistry. Current collectors include, but are not limited to, metal current collectors, carbon current collectors, conductive resin current collectors, metal and resin composite current collectors, and the like, more specifically copper, nickel, titanium, iron, and their respective alloys, stainless steel, carbon fibers, carbon Nanotubes (CNTs), graphite, and the like.

The second aspect of the embodiment of the application provides a preparation method of a pole piece, which comprises the following steps: providing an electrode slurry comprising a catheter material; coating the electrode slurry; the conduit material includes a first conduit that generates a capillary force to an electrolyte in contact with the pole piece.

The electrode paste can be manufactured by a general method or flexibly adjusted according to actual conditions. Illustratively, the active material, the catheter material, the conductive agent, the binder, and the solvent are mixed to obtain the electrode slurry. In the case where the active layer of the pole piece contains a thickener, the thickener may be added simultaneously. Wherein the solvent may comprise at least one of water and a non-aqueous solvent including, but not limited to, one or more of N-methylpyrrolidone (NMP), ethanol, propanol.

In the step of applying the electrode paste, the method of applying the electrode paste includes, but is not limited to, spin coating, blade coating, dip coating. After the coating treatment step, a drying, rolling, cutting, and the like process may be generally included.

A third aspect of the embodiment of the present application provides a battery monomer, where the battery monomer includes the pole piece described above, or includes a pole piece prepared by the method described above.

The battery cell is the most basic unit of a battery, and generally includes an electrode assembly and an electrolyte. The electrode assembly is typically composed of a positive electrode tab, a negative electrode tab, and a separator. The battery cell mainly relies on metal ions to move between the positive pole piece and the negative pole piece to work. The battery cells include, but are not limited to, lithium ion batteries, lithium sulfur batteries, sodium lithium ion batteries, sodium ion batteries, magnesium ion batteries, and the like. Typically, the battery cells may also be referred to as cells.

In some embodiments, the battery cell further comprises an electrolyte. The electrolyte may act as a carrier for ion transport in the battery cell.

In some embodiments, the electrolyte may be an electrolyte solution, which may include a solvent and a lithium salt dissolved in the solvent. The electrolyte may also contain a solid electrolyte such as a polymer electrolyte, an inorganic solid electrolyte, etc., but is not limited thereto.

The solvent in the electrolyte may be a nonaqueous organic solvent such as one or more of Ethylene Carbonate (EC), propylene Carbonate (PC), ethylmethyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), methyl Formate (MF), methyl Acetate (MA), ethyl Acetate (EA), propyl Acetate (PA), methyl Propionate (MP), ethyl Propionate (EP), propyl Propionate (PP), methyl Butyrate (MB), and Ethyl Butyrate (EB).

The lithium salt may be LiPF ₆ Lithium hexafluorophosphate, liBF ₄ Lithium tetrafluoroborate, liClO ₄ (lithium perchlorate), liAsF ₆ (lithium hexafluoroarsenate), liFeSI (lithium bis-fluorosulfonyl imide), liTFSI (lithium bis-trifluoromethanesulfonyl imide), liTFS (lithium trifluoromethanesulfonate), liDFOB (lithium difluorooxalato borate), liBOB (lithium bis-oxalato borate), liPO ₂ F ₂ One or more of (lithium difluorophosphate), liDFOP (lithium difluorooxalato phosphate) and LiTFOP (lithium tetrafluorooxalato phosphate), e.g. LiPF ₆ Lithium hexafluorophosphate, liBF ₄ One or more of (lithium tetrafluoroborate), liBOB (lithium bisoxalato borate), liBOB (lithium difluorooxalato borate), liTFSI (lithium bistrifluoromethanesulfonyl imide), and LiFSI (lithium bisfluorosulfonyl imide).

Other additives such as, but not limited to, one or more of ethylene carbonate (VC), ethylene carbonate (VEC), fluoroethylene carbonate (FEC), fluoroethylene carbonate (DFEC), trifluoromethylcarbonate (TFPC), succinonitrile (SN), adiponitrile (ADN), glutaronitrile (GLN), hexanetrinitrile (HTN), 1, 3-propane sultone (1, 3-PS), ethylene sulfate (DTD), methylene Methylsulfonate (MMDS), 1-propylene-1, 3-sultone (PST), 4-methylsulfonic acid ethylene (PCS), 4-ethylethylene sulfate (PES), 4-propylethylene sulfate (pegst), propylene sulfate (TS), 1, 4-butane sultone (1, 4-BS), ethylene sulfite (DTO), dimethyl sulfite (DMS), diethyl sulfite (DES), sulfonate cyclic quaternary ammonium salts, tri (trimethylsilane) phosphate (TMSP), and tri (trimethylsilane) borate (TMSB) may also be optionally included in the electrolyte.

In some embodiments, the battery cell further includes a separator stacked between the positive and negative electrode sheets. In some battery monomers, a diaphragm is required to be arranged to separate the positive electrode plate from the negative electrode plate, so that electrons in the battery monomers cannot pass freely, the contact short circuit of the two electrodes is prevented, and ions in the electrolyte can pass freely between the positive electrode and the negative electrode.

The separator may be any known porous separator having electrochemical stability and mechanical stability, such as a single-layer or multi-layer film of one or more of glass fiber, nonwoven fabric, polyethylene (PE), polypropylene (PP) and polyvinylidene fluoride (PVDF).

The positive pole piece and the negative pole piece are alternately laminated, and an isolating film is arranged between the positive pole piece and the negative pole piece to play a role in isolation, so that the bare cell is obtained, or the bare cell can be obtained after winding. The battery cell is placed in the shell, electrolyte is injected, and the battery cell is obtained by sealing, and the structures of the bare cell and the battery cell can be referred to as fig. 4.

In some embodiments, the battery cell may include an outer package. The outer package can be used for packaging the electrode assembly consisting of the positive electrode plate, the negative electrode plate and the diaphragm and electrolyte.

The outer package of the battery cell may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc.; but may also be a flexible bag, such as a bag-type flexible bag. The soft bag can be made of plastics such as polypropylene, polybutylene terephthalate, polybutylene succinate and the like.

The shape of the battery cell may be cylindrical, square, or any other shape.

A fourth aspect of the embodiment of the present application provides a battery, which includes the above-described battery cell.

Batteries are devices capable of converting chemical energy into electrical energy. The battery can be classified into a primary battery and a secondary battery according to whether the battery can be charged or not. The primary battery can not reactivate the active material in a charging mode after the battery is discharged, and has the characteristic of disposable discharge; secondary batteries, also referred to as rechargeable batteries or secondary batteries, refer to batteries that can be continuously used by activating an active material by charging after the battery is discharged. According to different packaging forms of the battery monomers, the battery is divided into a battery module and a battery pack.

In some battery packaging technologies, a plurality of battery monomers are firstly integrated into a battery module, and the battery module can provide higher voltage and capacity and has output with specific functions; the battery module is then mounted in a case of the battery, and a battery management system or the like is typically added to form a battery pack, which is typically a product provided to a user. In other battery packaging technologies, a plurality of battery monomers can be directly arranged in the box body to form a battery pack, and the intermediate state of the battery module is removed, so that the quality of the battery pack can be reduced, and the energy density of a battery can be improved.

In the embodiment of the application, the battery may refer to at least one of a primary battery and a secondary battery, and in the case that the battery is a secondary battery, the secondary battery may refer to at least one of a battery module and a battery pack.

The embodiment of the application also provides an electric device, which comprises the battery. The battery disclosed by the embodiment of the application can be used for an electric device which takes the battery as a power supply or various energy storage systems which take the battery as an energy storage element for providing electric energy. The powered device may include, but is not limited to, a cell phone, tablet, notebook computer, electric toy, electric tool, battery car, electric car, ship, spacecraft, and the like. Among them, the electric toy may include fixed or mobile electric toys, such as game machines, electric car toys, electric ship toys, electric plane toys, and the like, and the spacecraft may include planes, rockets, space planes, and spacecraft, and the like. As the electricity consumption device, a battery cell, a battery module, or a battery pack in the secondary battery may be selected according to the use requirements thereof.

The following description is made with reference to specific embodiments.

Example 1

The embodiment provides a negative electrode plate, including copper foil and coating the active layer on two surfaces of copper foil, the active layer includes that the mass ratio is 92:0.5:2:5.5 graphite, CMC (carboxymethyl cellulose), conductive graphite and polyvinylidene fluoride (PVDF), and also comprises a conduit material, the conduit material accounting for 0.2% of the total mass of the active layer.

The preparation method of the negative electrode plate in the embodiment comprises the following steps: graphite, CMC, conductive agent, adhesive and conduit material are mixed uniformly in proportion, water is added to form slurry with the solid content of 50%, and the anode pole piece, also called anode pole piece, is obtained after coating, drying, rolling and die cutting.

Wherein the conduit material comprises a plurality of conduits having a single-channel hollow pipeline-like structure, the structure is schematically shown in FIG. 5, each conduit has a continuous channel therein, the dimensions of all the conduits are distributed within a certain range, the outer diameter is mainly distributed between 140 and 200nm, the inner diameter is mainly distributed between 50 and 100nm, and the length is mainly distributed between 10 ³ ~10 ⁵ nm. The bulk material of the catheter material comprises silk fibroin SF and poly (glycolide-co-epsilon-caprolactone) PGCL.

The catheter material of the embodiment is prepared by an electrostatic spinning method, and specifically comprises the following steps:

SF and PGCL were dissolved in Hexafluoroisopropanol (HFIP) solvent to give SF solution at a concentration of 10% w/v and PGCL solution at a concentration of 10% w/v, respectively. The volume ratio of PGCL solution to SF solution is 5:5, mixing, stirring for 72 hours, and then performing ultrasonic treatment to completely dissolve and remove any bubbles, thereby obtaining a spinning solution. All the above solutions were prepared at room temperature (23.+ -. 2 ℃). And spinning the electrospinning liquid into a conduit material with a pipeline-shaped structure by adopting an electrostatic spinning device.

Example 2

The present embodiment provides a negative electrode sheet, which is different from embodiment 1 in that: the catheter material was 0.4% of the total mass of the active layer. The other components of the active layer, the proportion thereof, and the preparation method of the pole piece are the same as in example 1.

Example 3

The present embodiment provides a negative electrode sheet, which is different from embodiment 1 in that: the catheter material was 0.6% of the total mass of the active layer. The other components of the active layer, the proportion thereof, and the preparation method of the pole piece are the same as in example 1.

Example 4

The present embodiment provides a negative electrode sheet, which is different from embodiment 1 in that: the catheter material accounts for 0.8% of the total mass of the active layer. The other components of the active layer, the proportion thereof, and the preparation method of the pole piece are the same as in example 1.

Example 5

The present embodiment provides a negative electrode sheet, which is different from embodiment 1 in that: the catheter material accounts for 1% of the total mass of the active layer. The other components of the active layer, the proportion thereof, and the preparation method of the pole piece are the same as in example 1.

Example 6

The present embodiment provides a negative electrode sheet, which is different from embodiment 1 in that: the catheter material was 1.2% of the total mass of the active layer. The other components of the active layer, the proportion thereof, and the preparation method of the pole piece are the same as in example 1.

Example 7

The present embodiment provides a negative electrode sheet, which is different from embodiment 1 in that: the catheter material was 1.5% of the total mass of the active layer. The other components of the active layer, the proportion thereof, and the preparation method of the pole piece are the same as in example 1.

Comparative example 1

This comparative example provides a negative electrode sheet, which differs from example 1 in that: the active layer is free of catheter material. The other components of the active layer, the proportion thereof, and the preparation method of the pole piece are the same as in example 1.

Comparative example 2

This comparative example provides a negative electrode sheet, which differs from example 5 in that: the catheter material is replaced by porous carbon with the same mass (the pore diameter is distributed at 0.7-2 nm, and the particle size is distributed at 1-30 mu m). The other components of the active layer, the proportion thereof, and the preparation method of the pole piece are the same as in example 1.

(1) Effect of infiltration

1) The negative electrode sheets of example 1 and comparative example 1 were tested using a pole-sheet climbing method, and the test results are shown in fig. 6. As can be seen from fig. 6, the active layer of example 1, the pole piece incorporating the catheter material, requires less time to reach the same climbing height.

2) The Lucas-Washburn permeation model can be used to describe the imbibition kinetics of the pole piece in general, and the Lucas-Washburn equation is shown in the following equation:

wherein: h is the liquid absorption height; t is the imbibition time; r_is the form radius; sigma is the surface tension of the liquid; θ is the contact angle; η is the viscosity of the liquid.

As can be seen from the Lucas-Washburn equation, the square of the liquid immersion height H is proportional to the imbibition time t, and the square root K, which defines the ratio of the square of the immersion height H to the imbibition time t, is defined as the immersion rate, i.e。

The data in fig. 6 were processed to obtain fig. 7 in which the height of the climbing liquid was taken as the ordinate and the square root of time was taken as the abscissa, and the slope of the curve in fig. 7, i.e., the infiltration rate K.

As can be seen from fig. 7, the rate of penetration K of the conventional pole piece without the catheter material in comparative example 1 was 0.5908, while the rate of penetration K of the pole piece with the catheter material in example 1 was 0.7109, and the penetration effect of example 1 was better.

The negative electrode sheets of examples 2 to 7 and comparative example 2 were tested by the same method, and the respective infiltration rates K were obtained as shown in table 1.

(2) Electrochemical Properties

Selecting a 5-series ternary positive electrode active material (NCM 523, namely nickel cobalt lithium manganate with a nickel cobalt manganese molar ratio of 5:2:3), and mixing the positive electrode active material, conductive graphite and PVDF according to a molar ratio of 98:1:1 in a proper amount of N-methyl pyrrolidone (NMP) to form uniform anode slurry; and (3) coating the positive electrode slurry on the surface of a positive electrode current collector aluminum foil, and drying, cold pressing and die cutting to obtain the positive electrode plate. In an inert atmosphere glove box with water/oxygen less than 0.1ppm, the organic solvent Ethylene Carbonate (EC)/methylethyl carbonate (EMC)/diethyl carbonate (DEC) was prepared according to 3:6:1, and adding fully dried lithium hexafluorophosphate (LiPF) ₆ ) Stirring at normal temperature (23+ -2deg.C) for 30min to dissolve lithium hexafluorophosphate completely to obtain electrolyte.

The negative electrode plates of examples 1-7 and comparative examples 1-2 were laminated with the positive electrode plate to form 10Ah-20100140 soft-pack batteries [ i.e., rated capacities of 10Ah; size: 20×100×140 (mm), injecting the prepared electrolyte into a battery, performing formation and capacity division, testing the cycle performance of the battery at normal temperature of 25 ℃ for 300 cycles, and monitoring the expansion force in the process. The cyclic test voltage range is 2.8-4.2V, and the test current is 1C. The cell capacities after 300 cycles are shown in table 1 below.

The test results in table 1 reflect that as the doping amount of the catheter material in the pole piece increases, the infiltration rate K of the electrolyte to the pole piece gradually increases, which indicates that the catheter material can play a role in drainage of the electrolyte, accelerate the infiltration rate of the electrolyte in the pole piece, and greatly improve the infiltration of the pole piece.

Meanwhile, as shown in the embodiment 1, 0.2% of the catheter material is doped in the pole piece, after circulation, the battery cell can still keep higher capacity, and the capacity of the battery cell after circulation is the same as that of the battery cell without doping the catheter material in the comparative example 1, so that no obvious reduction occurs; meanwhile, the cell capacity of other embodiments is not obviously reduced compared with that of comparative example 1, which indicates that the electrolyte infiltration rate is improved and the cell capacity (or energy density) is not lost when a proper amount of catheter material is doped in the pole piece.

In addition, referring to example 5 and comparative example 2, the electrode sheet has a higher infiltration rate K to the electrolyte after the catheter material is incorporated in the electrode sheet, as compared to the electrode sheet in which porous carbon is incorporated.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the application, and are intended to be included within the scope of the appended claims and description. In particular, the technical features mentioned in the respective embodiments may be combined in any manner as long as there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions falling within the scope of the claims.

Claims

1. A pole piece comprising an active layer, the active layer comprising a conduit material, the conduit material comprising a first conduit that generates a capillary force to an electrolyte in contact with the pole piece;

the catheter material further comprises a second catheter having an inner diameter smaller than the inner diameter of the first catheter; the first conduit encloses one or more of the second conduits.

2. The pole piece of claim 1, wherein the interior of the first conduit has more than one continuous channel.

3. The pole piece of claim 1, wherein the axial direction of the second conduit forms an angle of less than 90 ° with the axial direction of the first conduit.

4. A pole piece according to any of claims 1 to 3, wherein the inner diameter of the first conduit is 50-1000 nm;

and/or the outer diameter of the first conduit is 50-1100 nm;

and/or the length of the first conduit is 200-10 ⁸ nm。

5. A pole piece according to any of claims 1 to 3, wherein the second conduit has an inner diameter of 10-500 nm;

and/or the length of the second conduit is 10-10 ⁸ nm。

6. A pole piece according to any of claims 1 to 3, wherein the inner diameter of the first conduit is 200-500 nm;

And/or the outer diameter of the first conduit is 50-200 nm;

and/or the length of the first conduit is 10 ³ ~10 ⁵ nm。

7. A pole piece according to any of claims 1 to 3, wherein the second conduit has an inner diameter of 10-250 nm;

and/or the length of the second conduit is 10 ³ ~10 ⁵ nm。

8. A pole piece according to any of claims 1-3, characterized in that the catheter material contains an electrolyte-philic functional group.

9. The pole piece of claim 8, wherein the electrophilic functional group comprises a C-N bond, carbonyl, C _1~3 One or more of alkyl, methoxy, ethoxy, carboxyl, ester groups.

10. The pole piece of claim 8, wherein the electrolyte-philic functional groups are distributed on the surface of any one or more of the inner wall of the first conduit and the outer wall of the first conduit;

and/or the conduit material comprises a second conduit, wherein the electrolyte-philic functional groups are distributed on the surface of any one or more of the inner wall of the first conduit, the outer wall of the first conduit, the inner wall of the second conduit and the outer wall of the second conduit.

11. The pole piece of claim 8, wherein the mass content of the electrolyte-philic functional group on the catheter material is 0.01% -30%.

12. The pole piece of claim 11, wherein the mass content of the electrolyte-philic functional group on the catheter material is 10% -20%.

13. The pole piece of claim 1, wherein the catheter material is present in the active layer in an amount of 0.01% -3% by mass.

14. The pole piece of claim 13, wherein the conduit material is present in the active layer in an amount of 0.05% -2% by mass.

15. The preparation method of the pole piece is characterized by comprising the following steps: providing an electrode slurry comprising a catheter material; coating the electrode slurry; the conduit material comprises a first conduit which generates capillary force to electrolyte contacted with the pole piece;

16. A battery cell comprising a pole piece according to any one of claims 1 to 14 or a pole piece prepared by a method according to claim 15.

17. A battery comprising the cell of claim 16.

18. An electrical device comprising the battery of claim 17.