CN121237805A - An electrode, a battery, and an electrical device - Google Patents

An electrode, a battery, and an electrical device

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Publication number
CN121237805A
CN121237805A CN202411183151.5A CN202411183151A CN121237805A CN 121237805 A CN121237805 A CN 121237805A CN 202411183151 A CN202411183151 A CN 202411183151A CN 121237805 A CN121237805 A CN 121237805A
Authority
CN
China
Prior art keywords
pole piece
region
battery
electrode
size
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202411183151.5A
Other languages
Chinese (zh)
Inventor
许占
赵可欣
胡瑜磊
袁晓涛
何科峰
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BYD Co Ltd
Original Assignee
BYD Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by BYD Co Ltd filed Critical BYD Co Ltd
Priority to CN202411183151.5A priority Critical patent/CN121237805A/en
Priority to PCT/CN2025/117038 priority patent/WO2026046189A1/en
Publication of CN121237805A publication Critical patent/CN121237805A/en
Pending legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/531—Electrode connections inside a battery casing
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

本发明公开了一种极片、电池及用电设备，极片包括极片主体以及与极片主体连接的至少一个极耳，极片主体包括集流体以及涂布在所述集流体表面的活性材料，所述极片主体在第一方向上包括至少三个区域，所述至少三个区域中至少两个区域涂布的活性材料不同；所述至少三个区域的中间区域的活性材料包括二次颗粒，其中，所述二次颗粒由多个一次颗粒形成。通过将极耳同侧引出的电极极片划分为至少三个区域，至少三个区域中至少两个区域涂布的活性材料不同；其中包括中间区域，中间区域的活性材料包括由多个一次颗粒形成的二次颗粒；可以改善极耳异侧引出的电极中靠近极耳侧和中间区域电流密度和电极阻抗分布不均的问题，从而提高电极的电化学性能。

This invention discloses an electrode, a battery, and an electrical device. The electrode includes an electrode body and at least one tab connected to the electrode body. The electrode body includes a current collector and an active material coated on the surface of the current collector. The electrode body includes at least three regions in a first direction, and at least two of the at least three regions are coated with different active materials. The active material in the middle region of the at least three regions includes secondary particles, wherein the secondary particles are formed by a plurality of primary particles. By dividing the electrode sheet led out from the same side of the tab into at least three regions, with at least two of the at least three regions coated with different active materials, including the middle region, the problem of uneven current density and electrode impedance distribution in the electrode led out from the opposite side of the tab in the region near the tab and the middle region can be improved, thereby improving the electrochemical performance of the electrode.

Description

Pole piece, battery and electric equipment
Technical Field
The invention relates to the technical field of batteries, in particular to a pole piece, a battery and electric equipment.
Background
In the existing lithium iron phosphate battery, the surface material of the positive electrode plate is uniformly distributed, the impedance of the electrode led out from the opposite side of the tab is smaller, so that the current density is higher, and the impedance of the middle position of the electrode is higher, so that the current density is lower. Further, the difference in current density and impedance causes a difference in the amount of heat generated by the electrodes.
Therefore, the positive electrode plate led out from the same side of the tab has obvious problems of uneven current density and temperature distribution.
Disclosure of Invention
In the summary, a series of concepts in a simplified form are introduced, which will be further described in detail in the detailed description. The summary of the invention is not intended to define the key features and essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
The invention provides a pole piece, which comprises a pole piece main body and at least one pole lug connected with the pole piece main body, wherein the pole piece main body comprises a current collector and active materials coated on the surface of the current collector, the pole piece main body comprises at least three areas in a first direction, the active materials coated on at least two areas in the at least three areas are different, the active materials in the middle area of the at least three areas comprise secondary particles, and the secondary particles are formed by a plurality of primary particles.
Illustratively, the secondary particles have a porous structure.
Illustratively, the primary particles have a first size and the secondary particles have a second size that is at least 30 times the first size.
Illustratively, when the first size and the second size are expressed as median diameters, the median diameter of the secondary particles ranges from 6 μm to 9 μm, and the median diameter of the primary particles ranges from 70nm to 130nm.
Illustratively, the first direction is a direction extending from the tab to the pole piece.
Illustratively, the length of the intermediate region along the first direction is 25% -35% of the length of the pole piece body.
Illustratively, the central region covers a center point of the pole piece body, and the distance between the central region and both ends of the pole piece body in the first direction is greater than 25% of the length of the pole piece body, and the center point is equidistant from both ends of the pole piece in the first direction.
Illustratively, the at least three regions further comprise first and second regions respectively located on the pole piece body, the first and second regions being aligned along the first direction and located at both ends of the intermediate region respectively, wherein the active material of the first and second regions comprises particles having a third size.
Illustratively, the particle size of the active material increases gradually from the middle region into the first region and the second region, respectively, of the at least three regions.
Illustratively, the third dimension is greater than the first dimension and less than the second dimension, and the median diameter of the particles having the third dimension ranges from 0.6 μm to 1.2 μm when the third dimension is expressed as a median diameter.
Illustratively, the active material includes a positive electrode active material.
Illustratively, the positive electrode active material includes lithium iron phosphate.
Illustratively, the pole pieces are used to form a heterolateral tab cell.
The invention also provides a battery, which comprises the pole piece.
Illustratively, the pole pieces include a positive pole piece and a negative pole piece, and the tab leading directions of the positive pole piece and the negative pole piece are the same.
The invention also provides electric equipment, which comprises the pole piece or the battery and the electric load, wherein the pole piece or the battery and the electric load are used for providing electric energy for the electric load.
According to the pole piece, the battery and the electric equipment, the electrode pole piece led out from the same side of the pole lug is divided into at least three areas, active materials coated in at least two areas in the at least three areas are different, the active materials in the middle area comprise secondary particles formed by a plurality of primary particles, and the problems of uneven current density and electrode impedance distribution of the electrode close to the side and the middle area of the electrode led out from the different side of the pole lug can be solved, so that the electrochemical performance of the electrode is improved.
Drawings
The following drawings are included to provide an understanding of the invention and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and their description to explain the principles of the invention.
In the accompanying drawings:
FIG. 1 is a schematic illustration of a pole piece according to one embodiment of the present invention;
fig. 2 is a schematic view of a structure of a battery according to an embodiment of the present invention.
Reference numerals
10. Pole piece main body 20 and pole lug
11. First region 12, second region
13. Central region
Detailed Description
In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the invention may be practiced without one or more of these details. In other instances, well-known features have not been described in detail in order to avoid obscuring the invention.
It should be understood that the present invention may be embodied in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the size of layers and regions, as well as the relative sizes, may be exaggerated for clarity. Like numbers refer to like elements throughout.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term "and/or" includes any and all combinations of the associated listed items.
In order to provide a thorough understanding of the present invention, detailed steps and detailed structures will be presented in the following description in order to explain the technical solution presented by the present invention. Preferred embodiments of the present invention are described in detail below, however, the present invention may have other embodiments in addition to these detailed descriptions.
Aiming at the batteries at the different sides of the electrode lugs, when the active materials are uniformly distributed, obvious problems of current density and uneven temperature exist in the extending direction of the electrode lugs. The current density of the areas of the two ends of the pole piece, which are close to the pole lugs, is high, the current density of the central area of the pole piece is low, the impedance is high, and the problem of uneven distribution of the pole piece surface group resistance is further aggravated by the lower reaction temperature, so that the performance of the battery is influenced.
In order to solve the problems, the invention provides a pole piece, as shown in fig. 1, wherein the pole piece comprises a pole piece main body 10 and at least one pole lug 20 connected with the pole piece main body, the pole piece main body 10 comprises a current collector and an active material coated on the surface of the current collector, the pole piece main body comprises at least three areas in a first direction, the active materials coated on at least two areas in the at least three areas are different, and the active material in the middle area of the at least three areas comprises secondary particles, wherein the secondary particles are formed by a plurality of primary particles.
Illustratively, the electrode sheet includes a positive electrode sheet or a negative electrode sheet, the electrode sheet body 10 includes an active material of a current collector and a current collector surface, and the tab 20 is composed of a metal material, and the single-layer metal material includes aluminum foil or copper foil.
In one embodiment, the pole piece is a positive pole piece. Taking a lithium ion battery as an example, a pole piece main body 10 of a positive pole piece of the lithium ion battery is generally formed by uniformly mixing a positive pole active material (such as lithium iron phosphate, lithium cobaltate, lithium manganate, ternary material and the like) with a conductive agent (such as carbon nano tube, conductive carbon black, graphene and the like) and a binder (such as polyvinylidene fluoride PVDF, sodium carboxymethyl cellulose and styrene-butadiene rubber) and the like, stirring the mixture into paste, uniformly coating the paste on two side surfaces of a positive pole current collector (such as aluminum foil), drying the paste under nitrogen flow to remove an organic matter dispersing agent, then performing compression molding by a roll squeezer, and cutting the paste into a specified size according to design requirements. The tab of the positive plate is led out from the positive current collector, and the tab of the positive plate is usually made of aluminum foil, and the length and the width of the tab can be designed according to the needs, so that the application is not limited.
In one embodiment, the pole piece is a negative pole piece. The negative active material of the negative plate of the lithium ion battery mainly comprises graphite, silicon base or lithium titanate, the negative current collector can adopt copper foil, and the preparation process of the negative plate is approximately the same as that of the positive plate, and is not repeated here. The tab of the negative electrode sheet is led out from the negative electrode current collector, the tab of the negative electrode sheet usually adopts copper foil, and the length and the width of the tab can be designed according to the needs, and the application is not limited to the above.
The lug and the current collector can be integrally formed and can be realized in a welding mode.
The pole piece body illustratively includes at least three regions in a first direction, at least two of the at least three regions being coated with different active materials, the active material of a middle region of the at least three regions including secondary particles, wherein the secondary particles are formed from a plurality of primary particles.
The electrode plate led out from the same side of the electrode lug is divided into at least three areas, at least two areas in the at least three areas are coated with different active materials, the active materials in the middle area comprise secondary particles formed by a plurality of primary particles, and the problems of uneven current density and electrode impedance distribution of the electrode close to the electrode lug side and the middle area in the electrode led out from the different side of the electrode lug can be solved, so that the electrochemical performance of the electrode is improved.
Illustratively, the secondary particles have a porous structure.
Because the secondary particles have more pore structures, a passage can be provided for lithium ion transmission, and thus the problem of nonuniform current density distribution of the electrode can be effectively solved.
In one embodiment, as shown in fig. 1, the first direction is a direction extending from the tab 20 toward the pole piece 10. The pole piece body 10 is divided into a first region 11, a middle region 13 and a second region 12 in sequence along a first direction in which the tab 20 extends toward the pole piece 10. It should be noted that the division of the pole piece body 10 into three regions is merely exemplary, and the pole piece body 10 may be divided into four, five or even more regions, which the present application is not limited to. Further, in addition to the above-described division of the pole piece body 10 into a plurality of regions along the first direction, the pole piece body may be further divided into a plurality of regions along a second direction, which is perpendicular to or intersects the first direction.
Because the current density and the temperature distribution of the pole piece are uneven in the direction extending from the pole lug 20 to the pole piece 10, the direction extending from the pole lug 20 to the pole piece 10 is taken as the first direction, and the area division is carried out based on the first direction, so that the problem of uneven current density and temperature distribution caused by even distribution of the pole piece surface material in the first direction can be effectively solved.
In one embodiment, the first direction includes a direction from a center point near the pole piece body 10 to a center point away from the pole piece body 10. The pole piece body 10 is divided into a plurality of regions sequentially from the inside to the outside from the center point of the pole piece body 10.
In one embodiment, the first direction includes a direction from a high current density to a low current density of the pole piece body 10. The pole piece body is divided into a plurality of areas according to the current density distribution. In one embodiment, the first direction includes a direction from a high temperature to a low temperature of the pole piece body 10. The pole piece body is divided into a plurality of areas according to temperature distribution.
Illustratively, the intermediate region covers a center point of the pole piece body.
In one embodiment, as shown in fig. 1, the middle region 13 not only covers the center point of the pole piece body 10, but the middle snack of the middle region 13 coincides with the center point of the pole piece body 10, at which time the length of the first region 11 is equal to the length of the second region 12. In one embodiment, the middle region 13 may also cover only the center point of the pole piece body 10, but the middle snack of the middle region 12 does not coincide with the center point of the pole piece body 10, where the length of the first region 11 is not equal to the length of the second region 12.
Illustratively, the length of the intermediate region is 25% -35% of the length of the pole piece body, and the distance between the intermediate region and both ends of the pole piece body in the first direction is greater than 25% of the length of the pole piece body.
In one embodiment, the cell energy density is lower when the length of the middle region 13 is smaller, the middle region current density is unevenly distributed, and the cell impedance is higher when the length of the middle region 13 is larger. Therefore, the length of the middle area along the first direction is 25% -35% of the length of the pole piece main body. Taking the length of the pole piece body 10 as L as an example, the length of the middle region 13 ranges from 0.25L to 0.35L.
In one embodiment, when the length of the middle region 13 ranges from 0.25L to 0.35L, and the center point of the middle region 13 coincides with the center point of the pole piece body 10, the lengths of the first region 11 and the second region 12 are both greater than 0.25L, the center point is equal to the two ends of the pole piece in the first direction, and when the center point of the middle region 13 does not coincide with the center point of the pole piece body 10, in order to avoid that the middle region 13 is too close to the edge of the pole piece body 10, the lengths of the first region 11 and the second region 12 need to be limited to be greater than 0.25L. In one embodiment, the length of the intermediate region 13 is 0.3L and the length of both the first region 11 and the second region 12 is 0.35L. In one embodiment, the lengths of the first region 11, the intermediate region 13, and the second region 12 are 0.3L, 0.35L, and 0.35L, respectively.
In one embodiment, table 1 shows the test results of the battery performance when the lengths of the intermediate regions are different.
The preparation process of the battery is as follows:
(1) Preparing a positive plate, namely mixing a positive active material, a conductive agent (conductive carbon black), a solvent (N-methylpyrrolidone) and a binder (PVDF), wherein the mass ratio of the positive active material to the conductive agent to the binder to the solvent is 100:1.5:2.5:50, preparing a positive slurry with moderate viscosity, coating the positive slurry on a positive current collector (aluminum foil), and drying to obtain the positive plate, wherein the selection and coating positions of the positive active material are shown in tables 1-4;
(2) Preparing a negative plate, namely mixing a negative active material (graphite powder), a conductive agent (conductive carbon black), a binder (mixture of CMC and SBR) and a solvent (water) to prepare a negative slurry with moderate viscosity, wherein the mass ratio of the positive active material to the conductive agent to the binder to the solvent is 100:0.8:2.5:50;
(3) Electrolyte LiPF 6 electrolyte (solvent is 15% DMC+40% EMC+15% DEC+30% EC) with concentration of 1 mol/L;
(4) Preparing a lithium ion battery, namely sequentially stacking the prepared positive electrode plate, the prepared diaphragm (PP film) and the prepared negative electrode plate in sequence, assembling the soft-package battery, injecting the prepared electrolyte, and performing electrochemical test, wherein the obtained results are shown in tables 1-4.
Electrochemical performance test:
(1) The current density difference test between the middle area and the tab side (i.e. the proximal area) of the pole piece comprises the steps of selecting 5 different positions in the proximal area and the distal area respectively for testing the current densities at corresponding positions, and calculating an average value, wherein the current density difference J between the proximal area and the proximal area of the pole piece is the current density difference between the distal area and the tab side of the pole piece as shown in tables 1-4, and the current density test of the pole piece is a conventional test in the field and is not particularly limited.
(2) And testing the energy density (Wh/L) of the battery, namely charging each prepared lithium ion battery at a 1/3C multiplying power at 25 ℃, discharging at a 1/3C multiplying power (the voltage interval is 2.2V-4.2V), and recording the actual discharge capacity, wherein the product of the actual discharge capacity of the battery discharged at 1/3C and the average voltage of the battery when discharging is the energy of the battery, and the ratio of the energy of the battery to the volume of the battery is the energy density (Wh/L) of the battery, as shown in tables 1-4.
(3) 50% SOC DC internal resistance (mΩ) the battery was discharged to 50% SOC, left for 2h,1C charged for 30s, left for 2h,1C discharged for 30s, and DC internal resistance at 1C rate was calculated as shown in tables 1-4.
(4) The capacity retention (%) was measured by charging and discharging the battery 0.5C/0.5C 1 time at 45 ℃ and then performing a 0.5C/0.5C charge and discharge test on the battery in a 45 ℃ incubator, and recording the discharge capacity C500,500 cycles after 500 th cycle=c500/c1×100%, as shown in tables 1 to 4.
Table 1 shows the battery performance test results when the lengths of the intermediate regions are different, and according to table 1, the lengths of the intermediate regions are in the range of 0.25L to 0.35L, the direct current internal resistance is smaller, the energy density is higher, and the battery performance is better, for example, when the battery performance is 0.3L.
TABLE 1
Illustratively, the active material of the intermediate region includes secondary particles having a porous structure, wherein the secondary particles are formed from a plurality of primary particles.
In one embodiment, taking lithium iron phosphate as an example of an active material, the active material used in the intermediate region 13 is secondary particles having a second size, which are formed from primary particles having a first size by agglomeration or sintering, or the like. The size of the secondary particles (i.e., the second size) is greater than the size of the primary particles (i.e., the first size), and the size of the secondary particles is at least 30 times, and typically 50 to 100 times, the size of the primary particles.
Here, the size refers to the particle diameter of the particles of the material. The particle size of the particles can be expressed as median diameter D50, i.e. the particle size corresponding to a cumulative percentage of particle size distribution of one sample reaching 50%, as measured by laser particle size analysis.
Specifically, when the first size and the second size are expressed by median diameters, the median diameter of the secondary particles for forming the intermediate region 13 ranges from 6 μm to 9 μm, and the median diameter of the primary particles for forming the secondary particles ranges from 70nm to 130nm.
In one embodiment, table 2 shows the test results of battery performance when the sizes of the secondary particles are different. When the primary particles are the same in size but the secondary particles formed are different in size, the battery performance is optimal when the median diameter of the secondary particles is in the range of 6 μm to 9 μm, for example, 7 μm, according to table 2.
TABLE 2
In one embodiment, table 3 shows the test results of battery performance when the primary particles are different in size. When the sizes of the secondary particles are the same but the sizes of the primary particles used to form the secondary particles are different, according to table 3, the performance of the battery is optimal when the median diameter of the primary particles is in the range of 70nm to 130nm, for example, 105 μm.
TABLE 3 Table 3
The lithium iron phosphate secondary particle material consists of a plurality of small-particle-size lithium iron phosphate primary particles, a plurality of pore structures are arranged in the lithium iron phosphate secondary particle material, a porous electrode structure is adopted in the middle area to provide a passage for lithium ion transmission, and the material with small primary particle size is used for reducing the impedance of the battery, so that the problem of uneven current density distribution in the length direction of the electrode is effectively solved.
Illustratively, the active material of the first and second regions includes particles having a third size.
Specifically, the particle size of the active material gradually increases from the intermediate region to the first region and the second region, respectively. Here, the particle size of the active material is the particle size of the primary particles.
Since the material having a small particle diameter can reduce the battery resistance, the resistances from the intermediate region to the first region and the second region, respectively, can be gradually reduced, solving the problem of uneven current density distribution.
The third dimension is greater than the first dimension and less than the second dimension, and the median diameter of the particles having the third dimension ranges from 0.6 μm to 1.2 μm when the third dimension is expressed as median diameter. The particles of the third size may be primary particles or secondary particles, and are preferably primary particles.
In one embodiment, the active material used to form the first region 11 and the second region 12 employs primary particles having a third size, the median diameter of the particles ranging from 0.6 μm to 1.2 μm, which is smaller than the size of the secondary particles used to form the intermediate region 13 described above (i.e., the second size), but larger than the size of the primary particles used to form the secondary particles (i.e., the first size).
In one embodiment, the active material includes a positive electrode active material.
Specifically, the positive electrode active material includes lithium iron phosphate.
In one embodiment, the pole pieces are used to form a heterolateral tab cell.
The invention also provides a battery, which comprises the pole piece.
In one embodiment, as shown in fig. 2, the battery comprises a heterolateral tab battery. The pole pieces comprise a positive pole piece and a negative pole piece, and the leading-out directions of the lugs of the positive pole piece and the negative pole piece are opposite.
The electrode lugs of the opposite electrode lug battery are distributed at two opposite ends of the battery, so that the current distribution of the electrode plate main body between the electrode lugs of the opposite electrode lug battery is small in current density and large in impedance of a middle area, and the current density of the electrode plate main body near the two end areas of the electrode lug is large.
In one embodiment, each cell consists of 1 pole piece, each pole piece consists of 34 positive pole pieces and 35 negative pole pieces, wherein the negative pole excess ratio is 15%, and the compaction is 1.60g/cm 3.
In one embodiment, table 4 shows the performance test results of a battery formed using the pole pieces described above. Among them, the schemes 14 to 15 are blank control groups. Wherein, scheme 14 does not use a zone arrangement and both coat the secondary particulate material, and scheme 15 does not use a zone arrangement and both coat the particulate material of the third size.
TABLE 4 Table 4
The invention also provides electric equipment, which comprises the pole piece or the battery and the electric load, wherein the pole piece or the battery and the electric load are used for providing electric energy for the electric load.
According to the pole piece, the battery and the electric equipment provided by the invention, the active material in the middle area of the pole piece adopts the secondary particles to form the porous structure so as to provide a passage for ion transmission, the secondary particles are formed by a plurality of primary particles, the particle size of the primary particles is small, the impedance of the battery is reduced, the problem of uneven current distribution on the surface of the pole piece is effectively solved, and the performance of the battery is improved.
The present invention has been illustrated by the above-described embodiments, but it should be understood that the above-described embodiments are for purposes of illustration and description only and are not intended to limit the invention to the embodiments described. In addition, it will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and that many variations and modifications are possible in light of the teachings of the invention, which variations and modifications are within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims (16)

1. The pole piece is characterized by comprising a pole piece body and at least one pole lug connected with the pole piece body, wherein the pole piece body comprises a current collector and active materials coated on the surface of the current collector, the pole piece body comprises at least three areas in a first direction, the active materials coated on at least two areas in the at least three areas are different, the active materials in the middle area of the at least three areas comprise secondary particles, and the secondary particles are formed by a plurality of primary particles.
2.A pole piece according to claim 1, characterized in that the secondary particles have a porous structure.
3. A pole piece according to claim 2, wherein the primary particles have a first size and the secondary particles have a second size, the second size being at least 30 times the first size.
4. A pole piece according to claim 2, wherein the median diameter of the secondary particles is in the range of 6 μm to 9 μm and the median diameter of the primary particles is in the range of 70nm to 130nm when the first and second dimensions are expressed as median diameters.
5. The pole piece of claim 2, wherein the first direction is a direction extending from the tab to the pole piece.
6. A pole piece according to claim 5, wherein the length of the intermediate region in the first direction is 25% -35% of the length of the pole piece body.
7. The pole piece of claim 6, wherein the intermediate region covers a center point of the pole piece body and the intermediate region is spaced from both ends of the pole piece body in the first direction by greater than 25% of the length of the pole piece body, the center point being equidistant from both ends of the pole piece in the first direction.
8. The pole piece of claim 2, wherein the at least three regions further comprise a first region and a second region on the pole piece body, respectively, the first region and the second region being aligned along the first direction and located at each end of the middle region, wherein the active material of the first region and the second region comprises particles having a third size.
9. The pole piece of claim 8, wherein the particle size of the active material increases progressively from the middle region to the first region and the second region, respectively, of the at least three regions.
10. A pole piece according to claim 9, characterized in that the third dimension is larger than the first dimension and smaller than the second dimension, the median diameter of the particles having the third dimension being in the range of 0.6 μm to 1.2 μm when the third dimension is expressed as median diameter.
11. The pole piece of claim 1, wherein the active material comprises a positive electrode active material.
12. The pole piece of claim 11, wherein the positive active material comprises lithium iron phosphate.
13. The pole piece of claim 1, wherein the pole piece is used to form a heterolateral tab battery.
14. A battery comprising a pole piece according to any one of claims 1 to 13.
15. The battery of claim 14, wherein the pole pieces comprise a positive pole piece and a negative pole piece, the tab extraction directions of the positive pole piece and the negative pole piece being opposite.
16. An electric device, characterized by comprising the pole piece of any one of claims 1-13 or the battery of claim 14, an electric load, the battery providing electric energy for the electric load.
CN202411183151.5A 2024-08-27 2024-08-27 An electrode, a battery, and an electrical device Pending CN121237805A (en)

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DE102016217390A1 (en) * 2016-09-13 2018-03-15 Robert Bosch Gmbh Electrode with local differences in porosity, method for producing such an electrode and their use
CN109841794B (en) * 2019-03-29 2021-07-20 东莞新能安科技有限公司 Electrode pole piece and electrochemical device comprising the electrode pole piece
CN116895741A (en) * 2022-03-30 2023-10-17 华为技术有限公司 Electrode plates, secondary batteries and terminal equipment
WO2024040420A1 (en) * 2022-08-23 2024-02-29 宁德时代新能源科技股份有限公司 Secondary battery and electric apparatus
CN218632101U (en) * 2022-12-05 2023-03-14 珠海冠宇电池股份有限公司 Pole piece and battery
CN219937079U (en) * 2023-04-11 2023-10-31 珠海冠宇电池股份有限公司 A pole piece and battery
CN220456451U (en) * 2023-07-04 2024-02-06 宁德时代新能源科技股份有限公司 Pole piece, electrode assembly, battery monomer, battery and electric equipment
CN116885097B (en) * 2023-09-06 2023-11-07 天津力神电池股份有限公司 Positive plate, preparation method thereof and battery

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