WO2025102469A1 - 一种电池极片及电池 - Google Patents

一种电池极片及电池 Download PDF

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Publication number
WO2025102469A1
WO2025102469A1 PCT/CN2023/138610 CN2023138610W WO2025102469A1 WO 2025102469 A1 WO2025102469 A1 WO 2025102469A1 CN 2023138610 W CN2023138610 W CN 2023138610W WO 2025102469 A1 WO2025102469 A1 WO 2025102469A1
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WO
WIPO (PCT)
Prior art keywords
coating
battery
groove
battery electrode
current collector
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
PCT/CN2023/138610
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English (en)
French (fr)
Inventor
程梦思
王超
曾汉民
何巍
刘金成
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.)
Eve Power Co Ltd
Huizhou Eve Power Co Ltd
Original Assignee
Eve Power Co Ltd
Huizhou Eve Power 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
Priority claimed from CN202323106765.7U external-priority patent/CN221427777U/zh
Priority claimed from CN202311535554.7A external-priority patent/CN117476865A/zh
Application filed by Eve Power Co Ltd, Huizhou Eve Power Co Ltd filed Critical Eve Power Co Ltd
Publication of WO2025102469A1 publication Critical patent/WO2025102469A1/zh
Anticipated expiration legal-status Critical
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
    • 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
    • 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

Definitions

  • the present application relates to the field of battery technology, and in particular to a battery pole piece and a battery.
  • the negative electrode of the battery will expand, causing extrusion, causing the electrolyte to gather on both sides of the electrode, causing lithium precipitation on the edges of the negative electrode, and the electrolyte reflux is blocked, which will cause the middle of the negative electrode to burn black due to insufficient electrolyte, thereby affecting the battery's cycle and fast charging performance.
  • How to avoid lithium precipitation and capacity retention rate diving caused by the obstruction of electrolyte circulation in the battery has become an urgent problem to be solved.
  • the present application provides a battery electrode to improve the liquid storage capacity of the battery electrode, alleviate the expansion of the battery electrode and lithium deposition on the two sides and the middle of the battery electrode, thereby improving the battery cycle and fast charging performance.
  • the present application provides a battery electrode, comprising: a current collector; a first coating, the first coating being arranged on any one side or both sides of the current collector; a second coating, the second coating being stacked on the first coating; and at least one groove, the groove being formed on the second coating.
  • the electrolyte is stored in the groove, which improves the wetting effect of the electrolyte on the battery electrode and the flow rate of the electrolyte in the battery electrode, thereby increasing the reaction area of the active material on the surface of the battery electrode, alleviating lithium deposition on both sides and the middle of the battery electrode, and providing additional space to alleviate the expansion of the electrode and the extrusion and crushing of the material, so as to improve the battery's cycle and fast charging performance, and extend the battery's cycle service life.
  • the present application provides a battery, comprising the battery electrode as described above.
  • the wetting effect of the electrolyte on the battery pole pieces and the flow rate of the electrolyte in the battery pole pieces are improved, thereby increasing the reaction area of the active material on the surface of the battery pole pieces, alleviating lithium precipitation on the sides and middle of the battery pole pieces, and providing additional space to alleviate the expansion of the pole pieces and the extrusion and crushing of the materials, so as to improve the battery's cycle and fast charging performance and extend the battery's cycle life.
  • FIG1 is a schematic structural diagram of a battery pole piece in a first embodiment of the present application.
  • FIG2 is another structural schematic diagram of the form 1 of the battery pole piece of the embodiment of the present application.
  • FIG3 is a schematic structural diagram of a second type of battery pole piece according to an embodiment of the present application.
  • FIG4 is a schematic structural diagram of a third form of a battery electrode sheet according to an embodiment of the present application.
  • FIG5 is a schematic structural diagram of a fourth form of a battery electrode sheet according to an embodiment of the present application.
  • FIG6 is a schematic structural diagram of a fifth form of a battery pole piece according to an embodiment of the present application.
  • FIG7 is a schematic structural diagram of a sixth form of a battery pole piece according to an embodiment of the present application.
  • FIG8 is another structural schematic diagram of the sixth form of the battery pole piece of the embodiment of the present application.
  • FIG9 is a schematic structural diagram of a seventh form of a battery pole piece according to an embodiment of the present application.
  • FIG. 10 is a schematic structural diagram of a form eight of a battery pole piece according to an embodiment of the present application.
  • the areal density of the first coating layer is greater than the areal density of the second coating layer.
  • the compaction density of the first coating layer is greater than the compaction density of the second coating layer.
  • the groove is arranged along the TD direction of the battery electrode sheet or along the MD direction of the battery electrode sheet.
  • the groove is vertically or obliquely arranged along the TD direction of the battery electrode.
  • the inclination angle of the groove is ⁇ , and the expression of ⁇ is: ;
  • S is the length of the current collector
  • L is the width of the active coating
  • At least two grooves are formed on the second coating layer, and the grooves are one or more of cross-distributed and spaced-distributed.
  • the depth of the groove on the current collector is d, and the expression of d is: ;
  • a is the length of the groove
  • b is the width of the groove
  • d is the depth of the groove on the current collector
  • P2 is the compaction density of the second coating
  • w2 is the proportion of active material on the second coating
  • d2 is the thickness of the second coating
  • S is the length of the current collector
  • L is the width of the active coating
  • d1 is the thickness of the first coating
  • P1 is the compaction density of the first coating
  • w1 is the proportion of active material on the first coating
  • M is the weight of active material on the active coating
  • n is the number of grooves on the current collector.
  • the active material loss ratio caused by constructing the groove on any side of the current collector is R, and the expression of R is: .
  • the depth of the groove on the current collector satisfies d ⁇ d 2 ; wherein d is the depth of the groove on the current collector, and d 2 is the thickness of the second coating layer.
  • the proportion of active material loss caused by constructing the groove (4) on any side of the current collector (1) is R, and the expression of R is: .
  • the width of the groove is less than or equal to the width of the active coating.
  • the length of the groove is less than or equal to the length of the current collector.
  • the present application discloses a battery pole piece, the battery pole piece includes a current collector 1, a first coating 2, a second coating 3 and at least one groove 4.
  • the first coating 2 is arranged on any one side or both sides of the current collector 1
  • the second coating 3 is stacked on the first coating 2
  • the groove 4 is formed on the second coating 3, wherein the first coating 2 and the second coating 3 are both composed of active materials.
  • the wettability of the electrolyte to the battery pole piece and the liquid storage capacity of the battery pole piece are improved, the contact reaction area of the active material of the battery pole piece is increased, the expansion of the battery pole piece and the lithium precipitation on the two sides and the middle of the battery pole piece are alleviated, thereby improving the cycle and fast charging performance of the battery.
  • one or more grooves 4 are provided on the second coating 3.
  • the grooves 4 on the second coating 3 can be determined according to actual conditions.
  • the electrolyte is stored in the grooves 4 to improve the wetting effect of the electrolyte on the battery electrode and the flow rate of the electrolyte in the battery electrode, thereby increasing the reaction area of the active material on the surface of the battery electrode, alleviating lithium deposition on both sides and the middle of the battery electrode, and providing additional space to alleviate the expansion of the electrode and the extrusion and crushing of the material, so as to improve the battery's cycle and fast charging performance, and extend the battery's cycle service life.
  • the first coating layer 2 and the second coating layer 3 are stacked on any one side or both sides of the current collector 1 to form an active coating layer.
  • the other side of the current collector 1 may be provided with a corresponding active material to form another active coating layer.
  • the grooves 4 on the second coating layer 3 can be formed by roller rolling.
  • a protrusion is provided on the roller.
  • the sizes of the multiple protrusions on the roller are different from each other.
  • the setting directions of the multiple protrusions on the roller are different from each other.
  • a roller with protrusions of different sizes and different setting directions on the surface is used to roll the second coating layer 3 on the current collector 1 to form multiple grooves 4 of different sizes and different setting directions on the second coating layer 3.
  • the groove 4 on the second coating 3 can be formed by laser burning.
  • the active material on the second coating 3 can be burned by laser to form the groove 4 on the second coating 3; optionally, after the active material coated on the current collector 1 is cold pressed, the active material on the second coating 3 can be burned by laser to form the groove 4 on the second coating 3; optionally, before the current collector 1 stacked with the first coating 2 and the second coating 3 is wound, the active material on the second coating 3 can be burned by laser to form the groove 4 on the second coating 3; further, the active material on the battery pole piece after burning can be adsorbed and removed by equipment such as a dust collector, without the need to add an additional process for cleaning the pole piece.
  • the second coating 3 can be fully coated on the side of the first coating 2 away from the current collector 1, and the groove 4 can be formed on the second coating 3 by laser etching or rolling, that is, the second coating 3 can still exist at the bottom of the groove 4 to reduce the loss of active materials; optionally, the second coating 3 can be coated on any area of the side of the first coating 2 away from the current collector 1, and the groove 4 can be directly formed on the second coating 3 by a double-layer coating process, thereby increasing the construction speed of the groove 4 and leaving the bottom of the groove 4 without the second coating 3.
  • the first coating 2 and the second coating 3 are respectively arranged in different areas on the same side of the current collector 1.
  • the first coating 2 and the second coating 3 are arranged in a stacked manner.
  • the first coating 2 is coated on the current collector 1, and the second coating 3 is coated on the first coating 2.
  • the surface density of the first coating 2 is greater than the surface density of the second coating 3, and the groove 4 is arranged in the second coating 3 to avoid excessive loss of active materials on the current collector 1 after the groove 4 is opened on the second coating 3, which has a great impact on the rated capacity or charging NP ratio of the battery, resulting in low capacity or lithium precipitation and other adverse phenomena, seriously affecting the cycle performance and storage performance of the battery.
  • the surface density of the first coating 2 is greater than the surface density of the second coating 3, and the groove 4 is arranged in the second coating 3, which can reduce the loss of active materials caused by setting the groove 4 on the second coating 3, and effectively reduce the impact of setting the groove 4 in the second coating 3 on the cycle performance and storage performance of the battery.
  • the battery capacity is positively correlated with the compaction density, that is, the greater the compaction density, the greater the battery capacity.
  • the compaction density of the first coating 2 is greater than the compaction density of the second coating 3 to avoid opening the groove 4 on the second coating 3, resulting in a large change in the compaction density of the active material on the current collector 1, resulting in a significant decrease in the battery capacity, thereby reducing the impact of setting the groove 4 on the second coating 3 on the battery capacity.
  • the thickness of the first coating layer 2 is greater than the thickness of the second coating layer 3.
  • the first coating layer 2 and the second coating layer 3 are stacked, and the groove 4 is provided in the second coating layer 3 to avoid the opening of the groove 4, which causes excessive loss of active materials on the current collector 1 and affects the cycle performance and storage performance of the battery, that is, the thickness of the first coating layer 2 is greater than the thickness of the second coating layer 3 to reduce the loss of active materials when the groove 4 is provided on the second coating layer 3, and effectively ensure the cycle performance and storage performance of the battery after the groove 4 is provided in the second coating layer 3.
  • the first coating 2 and the second coating 3 are respectively arranged in different areas on the same side of the current collector 1.
  • the first coating 2 and the second coating 3 are arranged in a stacked manner.
  • the first coating 2 is coated on the current collector 1
  • the second coating 3 is coated on the first coating 2, wherein the surface density of the first coating 2 is greater than the surface density of the second coating 3, and the thickness of the first coating 2 is greater than the thickness of the second coating 3.
  • the compaction density of the first coating 2 is greater than the compaction density of the second coating 3, thereby fully reducing the effect of setting the groove 4 on the second coating 3 on the mass, surface density and compaction density of the active material on the current collector 1, thereby avoiding a decrease in the capacity, cycle performance and storage performance of the battery due to setting the groove 4 on the second coating 3.
  • the battery pole piece can be a battery positive pole piece.
  • the active material can be made of any one or a mixture of lithium ferrous phosphate, ternary materials nickel cobalt manganese, lithium manganate, lithium cobalt oxide and nickel cobalt aluminum oxide, etc.;
  • the active material made of any one or a mixture of lithium ferrous phosphate, ternary materials nickel cobalt manganese, lithium manganate, lithium cobalt oxide and nickel cobalt aluminum oxide, etc. is arranged layer by layer in different areas on the same side of the current collector 1, so that the first coating 2 and the second coating 3 arranged in a stacked manner are formed on the current collector 1.
  • the battery pole piece can be a battery negative pole piece.
  • the active material can be made of any one or a mixture of artificial graphite, natural graphite, hard carbon, soft carbon and silicon.
  • the active material made of any one or a mixture of artificial graphite, natural graphite, hard carbon, soft carbon and silicon is arranged layer by layer in different areas on the same side of the current collector 1 to form the first coating 2 and the second coating 3 in a stacked arrangement on the current collector 1.
  • the groove 4 on the second coating 3 can be determined according to actual conditions, and the width, length and depth of the groove 4 need to be fully considered to avoid affecting the rated capacity of the battery or the charging N/P ratio as much as possible, where the N/P ratio is the ratio of the negative electrode capacity to the positive electrode capacity of the battery.
  • the length of the groove 4 is less than or equal to the length of the current collector 1.
  • the length of the groove 4 is ⁇ 0.005 mm, that is, the current minimum value of the length of the groove 4 can be 0.005 mm, but with the development of processing technology and corresponding processing equipment, the minimum value of the length of the groove 4 can be further reduced to the range of (0, 0.005 mm).
  • the maximum value of the length of the groove 4 is equal to the length of the current collector 1, which limits the groove 4 from appearing on the current collector 1 to prevent the phenomenon of pole segment breakage due to uneven tension in subsequent processes such as winding.
  • the groove 4 is less than or equal to the width of the active coating.
  • the width of the groove 4 is ⁇ 0.005 mm, that is, the current minimum value of the width of the groove 4 can be 0.005 mm, but with the development of processing technology and corresponding processing equipment, the minimum value of the width of the groove 4 can be further reduced to the range of (0, 0.005 mm).
  • the width of the groove 4 can be equal to the width of the active coating, that is, the length of the groove 4 in the MD direction can be equal to the length of the pole piece, which also means that the groove 4 can pass through the material area of the battery pole piece, but cannot touch the pole ear. If the pole ear is damaged, the belt is likely to break during subsequent winding.
  • the proportion of active material loss caused by constructing the groove 4 on any side of the current collector 1 is R.
  • the value range of R is [0.01%, 20%].
  • the number of the grooves 4 is limited by limiting the amount of active material loss to avoid excessive loss of active material on the current collector 1, which will have a great impact on the rated capacity or charging NP ratio of the battery, resulting in low capacity or lithium precipitation and other undesirable phenomena.
  • the groove 4 when the groove 4 is constructed by laser etching or layered coating process, the loss of active materials that is inevitable in the existing production process can be avoided to affect the opening of the groove 4, so R needs to meet ⁇ 0.01%, and at the same time, it is avoided that the active material on the current collector 1 is lost too much, which has a great impact on the rated capacity or charging NP ratio of the battery, resulting in low capacity or lithium precipitation and other undesirable phenomena, so R needs to meet ⁇ 20%;
  • the groove 4 when the groove 4 is constructed by the rolling process, since the spatial volume of the groove 4 must exist when the rolling process is used to construct the groove 4, R needs to meet ⁇ 0.01%, and the compaction density of the bottom coating of the groove 4 will increase during the rolling process, which will affect the rate of lithium deintercalation of the active material of this part of the coating, so R needs to meet ⁇ 20%;
  • the length and width of the groove 4 on the current collector 1 are set to be a and b respectively; the depth of the groove 4 on the current collector 1 is d; the length of the current collector 1 is S; the width of the active coating (that is, the active coating formed by the first coating 2 and the second coating 3) is L; d1 is the thickness of the first coating material area, and d2 is the thickness of the second coating material area; M is the weight of the active material on the active coating; n is the number of grooves 4 on the current collector 1; P1 is the compaction density of the normal area on the current collector 1, that is, the compaction density of the first coating 2; w1 is the proportion of the active material on the first coating 2; P2 is the compaction density of the area on the current collector 1 where the groove 4 is provided, that is, the compaction density of the second coating 3, and optionally, P1 ⁇ P2 ; w2 is the proportion of the active material on the second coating 3;
  • the depth d of the groove 4 on the current collector 1 is expressed as follows:
  • the depth d of the groove 4 on the current collector 1 must satisfy d ⁇ d 2 , limiting the depth of the groove 4 to prevent the active material at the bottom of the groove 4 from being too compacted due to the depth being too large, causing the active material to be "crushed" and unable to normally release lithium.
  • the inclination angle of the groove 4 is ⁇ ;
  • the expression of the tilt angle ⁇ is as follows:
  • the ratio R of the groove 4 can be expressed as follows:
  • the expression of the ratio R of the groove 4 that can be set is as follows:
  • the cross-sectional shape of the groove 4 is not fixed.
  • the cross-sectional shape of the groove 4 can be one of a rectangle, a trapezoid, a cone and an arc; optionally, the distribution position of the groove 4 is not fixed.
  • the groove 4 is evenly distributed on the second coating 3; optionally, the groove 4 is distributed in a local area of the second coating 3; optionally, the cross-sectional shape of the groove 4 on the same second coating 3 is also not fixed, that is, the cross-sectional shape of the groove 4 on the same second coating 3 can be one or more of a rectangle, a trapezoid, a cone and an arc; optionally, the grooves 4 on the same second coating 3 can be distributed at intervals, that is, the grooves 4 are independent and separated from each other, or the grooves 4 are parallel to each other, or the grooves 4 are cross-distributed. Further, the second coating 3 has both cross-distributed grooves 4 and spaced grooves 4, that is, the grooves are one or more of cross-distributed and spaced distribution.
  • a battery includes the battery electrode sheet described above.
  • the form of the battery electrode sheet is as shown in FIG. 1 and FIG. 2 , and the groove 4 on the second coating 3 is vertically arranged along the TD direction of the battery electrode sheet (corresponding to the height direction of the battery), so as to construct a vertical channel along the TD direction of the battery electrode sheet on the battery electrode sheet, so that the battery electrode sheet can store electrolyte through the vertical channel along the TD direction of the battery electrode sheet, thereby improving the wetting effect of the electrolyte on the battery electrode sheet and the flow speed of the electrolyte in the battery electrode sheet, thereby increasing the reaction area of the active material on the surface of the battery electrode sheet and improving the reaction activity;
  • the second form of the battery electrode is shown in Figure 3, and the groove 4 on the second coating 3 is inclined along the TD direction of the battery electrode (corresponding to the height direction of the battery), thereby constructing an inclined channel along the TD direction of the battery electrode on the battery electrode, so that the battery electrode can greatly increase the reaction area of the active material on the surface of the battery electrode and the ability to store electrolyte through the inclined channel along the TD direction of the battery electrode, improve the wetting effect of the electrolyte on the battery electrode and the flow rate of the electrolyte in the battery electrode, and can also serve as a gas exhaust channel, effectively reducing the pressure inside the battery, improving the safety performance of the battery, and can alleviate the occurrence of side reactions between the battery electrodes.
  • form three of the battery electrode is shown in Figure 4, and the groove 4 on the second coating 3 is arranged straight along the MD direction of the battery electrode (corresponding to the width direction of the battery), so as to construct a straight channel along the MD direction of the battery electrode on the battery electrode, so that the battery electrode can store electrolyte through the straight channel along the MD direction of the battery electrode, thereby improving the wetting effect of the electrolyte on the battery electrode and the flow rate of the electrolyte in the battery electrode, thereby increasing the reaction area of the active material on the surface of the battery electrode and improving the reaction activity, and providing additional space to alleviate the expansion effect of the battery electrode and the extrusion and crushing of the material, while improving the uneven current in the middle and on both sides of the battery electrode.
  • the form of the battery electrode sheet is shown in Figure 5, and the second coating 3 is provided with the groove 4 which is vertically arranged along the TD direction of the battery electrode sheet (corresponding to the height direction of the battery), and the second coating 3 is also provided with the groove 4 which is straightly arranged along the MD direction of the battery electrode sheet (corresponding to the width direction of the battery), so that a vertical channel along the TD direction of the battery electrode sheet and a straight channel along the MD direction of the battery electrode sheet are constructed on the battery electrode sheet.
  • the vertical channel and the straight channel are cross-distributed, so that the battery electrode sheet can store electrolyte through the channels cross-distributed along the TD direction of the battery electrode sheet and along the MD direction of the battery electrode sheet, thereby improving the wetting effect of the electrolyte on the battery electrode sheet and the flow rate of the electrolyte in the battery electrode sheet, thereby increasing the reaction area of the active material on the surface of the battery electrode sheet and improving the reaction activity, and providing additional space to alleviate the expansion effect of the battery electrode sheet and the extrusion and crushing of the material, and at the same time improving the uneven current in the middle and on both sides of the battery electrode sheet.
  • the form of the battery electrode sheet is shown in FIG. 6 , and the second coating 3 is provided with the groove 4 which is inclined along the TD direction of the battery electrode sheet (corresponding to the height direction of the battery), and the second coating 3 is also provided with the groove 4 which is straightly arranged along the MD direction of the battery electrode sheet (corresponding to the width direction of the battery), thereby constructing an inclined channel along the TD direction of the battery electrode sheet and a straight channel along the MD direction of the battery electrode sheet on the battery electrode sheet, and optionally, the inclined channel and the straight channel are arranged in a cross-distribution so that the battery electrode sheet can pass through the TD direction and the MD direction of the battery electrode sheet.
  • the channels cross-distributed along the MD direction of the battery pole piece greatly increase the reaction area of the active material on the surface of the battery pole piece and the ability to store electrolyte, enhance the wetting effect of the electrolyte on the battery pole piece and the flow rate of the electrolyte in the battery pole piece, improve the battery's cycle and fast charging performance, especially improve the uneven current in the middle and on both sides of the battery pole piece, and can also serve as a gas discharge channel, effectively reducing the pressure inside the battery, improving the safety performance of the battery, and can alleviate the occurrence of side reactions between the battery pole pieces, and can further provide additional space to alleviate the expansion of the battery pole piece and material extrusion, crushing, etc.
  • the form of the battery electrode sheet is shown in Figures 7 and 8, and the second coating 3 is provided with a plurality of grooves 4 vertically arranged along the TD direction of the battery electrode sheet (corresponding to the height direction of the battery), so that a plurality of vertical channels along the TD direction of the battery electrode sheet are constructed on the battery electrode sheet, so that the battery electrode sheet can store electrolyte through the plurality of vertical channels along the TD direction of the battery electrode sheet, improve the infiltration effect of the electrolyte on the battery electrode sheet and the flow speed of the electrolyte in the battery electrode sheet, thereby increasing the reaction area of the active material on the surface of the battery electrode sheet and improving the reaction activity. Furthermore, by providing additional space through the dispersed plurality of vertical channels, it is convenient to alleviate the expansion effect of the battery electrode sheet and the extrusion and crushing of the material, and the impedance of the battery electrode sheet can be reduced;
  • the second coating 3 is provided with a plurality of grooves 4 which are arranged in a straight manner along the MD direction of the battery electrode (corresponding to the width direction of the battery), thereby constructing a plurality of straight channels along the MD direction of the battery electrode on the battery electrode, so that the battery electrode can store electrolyte through the plurality of straight channels along the MD direction of the battery electrode, thereby improving the wetting effect of the electrolyte on the battery electrode and the flow rate of the electrolyte in the battery electrode, thereby increasing the reaction area of the active material on the surface of the battery electrode and improving the reaction activity, while improving the battery's cycle and fast charging performance, especially improving the phenomenon of uneven current in the middle and on both sides of the battery electrode. Furthermore, by providing additional space through the dispersed plurality of straight channels, it is convenient to alleviate the expansion effect of the battery electrode and the extrusion and crushing of the material, and can reduce the impedance of the battery electrode.
  • the form of the battery electrode sheet is shown in Figure 9, and the second coating 3 is provided with the groove 4 arranged along the TD direction of the battery electrode sheet (corresponding to the height direction of the battery), and the second coating 3 is also provided with the groove 4 arranged along the MD direction of the battery electrode sheet (corresponding to the width direction of the battery), thereby constructing a channel arranged along the TD direction of the battery electrode sheet and a channel arranged along the MD direction of the battery electrode sheet on the battery electrode sheet.
  • the channel arranged along the TD direction of the battery electrode sheet can be independently distributed from the channel arranged along the MD direction of the battery electrode sheet.
  • the channel arranged along the TD direction of the battery electrode sheet is cross-distributed with the channel arranged along the MD direction of the battery electrode sheet.
  • there is both The channels arranged along the TD direction of the battery electrode sheet can be distributed independently of the channels arranged along the MD direction of the battery electrode sheet, and the channels arranged along the TD direction of the battery electrode sheet and the channels arranged along the MD direction of the battery electrode sheet are cross-distributed, so that the battery electrode sheet can greatly increase the reaction area of the active material on the surface of the battery electrode sheet and the ability to store electrolyte through the channels arranged along the TD direction of the battery electrode sheet and the channels arranged along the MD direction of the battery electrode sheet, improve the wetting effect of the electrolyte on the battery electrode sheet and the flow speed of the electrolyte in the battery electrode sheet, improve the phenomenon of uneven current in the middle and on both sides of the battery electrode sheet, and can further provide additional space to alleviate the expansion of the battery electrode sheet and the extrusion and crushing of the material
  • the form of the battery electrode sheet is shown in FIG. 10, and the second coating 3 is provided with the groove 4 arranged along the TD direction of the battery electrode sheet (corresponding to the height direction of the battery), and the second coating 3 is also provided with the groove 4 arranged along the MD direction of the battery electrode sheet (corresponding to the width direction of the battery), wherein the channel arranged along the TD direction of the battery electrode sheet and the channel arranged along the MD direction of the battery electrode sheet are arranged in a cross-distribution, and further, the second coating 3 is also provided with a plurality of channels arranged along the TD direction of the battery electrode sheet that are independent of the channels arranged in a cross-distribution and the channels arranged along the MD direction of the battery electrode sheet.
  • the groove 4 of the channel arranged in the MD direction of the battery electrode thereby constructing channels arranged in a cross distribution and channels independent of the cross distribution on the battery electrode, so that the battery electrode can store electrolyte through the above-mentioned channel, improve the wetting effect of the electrolyte on the battery electrode and the flow rate of the electrolyte in the battery electrode, increase the reaction area of the active material on the surface of the battery electrode, alleviate lithium deposition on both sides and the middle of the electrode, provide additional space to facilitate the alleviation of electrode expansion and material extrusion or crushing, improve the cycle and fast charging performance of the battery, and reduce the impedance of the battery electrode.

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Abstract

一种电池极片及电池，所述电池极片包括：集流体；第一涂层，所述第一涂层设置在所述集流体的任意一侧或两侧；第二涂层，所述第二涂层层叠设置在所述第一涂层上；至少一个凹槽，所述凹槽形成于所述第二涂层上。通过所述凹槽储存电解液，提升电解液对所述电池极片的浸润效果及电解液在所述电池极片中的流动速度，从而实现增大所述电池极片表面活性材料的反应面积，缓解极片两侧及中部析锂，并提供额外的空间便于缓解极片膨胀作用及材料挤压、破碎等情况，以改善电池的循环及快充等性能，延长了电池的循环使用寿命。

Description

一种电池极片及电池
本申请要求在2023年11月16日提交中国专利局、申请号为2023231067657的中国专利申请以及在2023年11月16日提交中国专利局、申请号为2023115355547的中国专利申请的优先权，以上申请的全部内容通过引用结合在本申请中。
技术领域
本申请涉及电池技术领域，尤其涉及一种电池极片及电池。
 背景技术
随着新能源时代的迅猛发展，锂电池的高速发展也随之而来。近年，如手机、平板等电子设备更新换代十分频繁，同时混合动力汽车和新能源电动汽车也逐渐普及等，人们对新能源行业的产品的性能提出了更高的要求。因此，具有大容量、高能量密度以及满足快速充放电的高性能锂离子二次电池受到广泛关注。但由此产生的安全问题也备受关注，特别是电池着火、电池爆炸等问题应该得到进一步重视和解决。在电池长期使用的过程中，电池的负极极片会发生膨胀，从而造成挤压，致使电解液向极片两侧聚集，造成负极两侧边缘析锂，且电解液回流受阻会使负极片中部因没有足够的电解液导致烧黑，进而影响电池的循环和快充等性能。如何避免电池内部因电解液流通受阻而导致的循环、快充等发生析锂、容量保持率跳水等问题，成为迫切需要解决的问题。
 技术问题
为了克服上述现有技术所述的至少一种缺陷，本申请提供一种电池极片，提高所述电池极片的储液能力，缓解所述电池极片膨胀及所述电池极片两侧及中部析锂等，从而改善电池的循环及快充性能。
技术方案
第一方面，本申请提供了一种电池极片，包括：集流体；第一涂层，所述第一涂层设置在所述集流体的任意一侧或两侧；第二涂层，所述第二涂层层叠设置在所述第一涂层上；至少一个凹槽，所述凹槽形成于所述第二涂层上。
在本电池极片中，通过所述凹槽储存电解液，提升电解液对所述电池极片的浸润效果及电解液在所述电池极片中的流动速度，从而实现增大所述电池极片表面活性材料的反应面积，缓解所述电池极片两侧及中部析锂，并提供额外的空间便于缓解极片膨胀作用及材料挤压、破碎等情况，以改善电池的循环及快充等性能，延长了电池的循环使用寿命。
第二方面，本申请提供了一种电池，包括如上所述的电池极片。
 有益效果
通过凹槽储存电解液，提升电解液对电池极片的浸润效果及电解液在电池极片中的流动速度，从而实现增大电池极片表面活性材料的反应面积，缓解电池极片两侧及中部析锂，并提供额外的空间便于缓解极片膨胀作用及材料挤压、破碎等情况，以改善电池的循环及快充等性能，延长了电池的循环使用寿命。
 附图说明
图1为本申请实施例的电池极片的形式一的结构示意图；
图2为本申请实施例的电池极片的形式一的又一结构示意图；
图3为本申请实施例的电池极片的形式二的结构示意图；
图4为本申请实施例的电池极片的形式三的结构示意图；
图5为本申请实施例的电池极片的形式四的结构示意图；
图6为本申请实施例的电池极片的形式五的结构示意图；
图7为本申请实施例的电池极片的形式六的结构示意图；
图8为本申请实施例的电池极片的形式六的又一结构示意图；
图9为本申请实施例的电池极片的形式七的结构示意图；
图10为本申请实施例的电池极片的形式八的结构示意图。
其中，附图标记含义如下：
1、集流体；2、第一涂层；3、第二涂层；4、凹槽。
 本发明的实施方式
在本申请的描述中，需要说明的是，术语“上”、“下”、“前”、“后”、“左”、“右”、“竖直”、“水平”、“顶”、“底”、“内”、“外”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本申请和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本申请的限制。
除非另有定义，本文所使用的所有的技术和科学术语与属于本申请的技术领域的技术人员通常理解的含义相同。本文中在本申请的说明书中所使用的术语只是为了描述具体的实施例的目的，不是旨在限制本申请。
在一实施例中，所述第一涂层的面密度大于所述第二涂层的面密度。
在一实施例中，所述第一涂层的压实密度大于所述第二涂层的压实密度。
在一实施例中，所述凹槽沿所述电池极片的TD方向设置或者沿所述电池极片的MD方向设置。
在一实施例中，所述凹槽沿所述电池极片的TD方向呈竖直设置或倾斜设置。
在一实施例中，所述凹槽的倾斜角度为α，α的表达式： ；
其中S为所述集流体的长度，L为活性涂层的宽度。
在一实施例中，所述第二涂层上形成有至少两个所述凹槽，所述凹槽为交叉分布和间隔分布的其中一种或多种。
在一实施例中，当所述凹槽通过激光刻蚀或分层涂布构建时，所述凹槽在所述集流体上的深度为d，d的表达式: ；
其中a为所述凹槽的长度，b为所述凹槽的宽度，d为所述凹槽在所述集流体上的深度，P 2为所述第二涂层的压实密度，w 2为所述第二涂层上的活性材料的占比，d 2为第二涂层的厚度，S为所述集流体的长度，L为活性涂层的宽度，d 1为第一涂层的厚度，P 1为所述第一涂层的压实密度，w 1为所述第一涂层上的活性材料的占比，M为活性涂层上的活性材料的重量，n为所述集流体上凹槽的数量。
在一实施例中，所述集流体的任意一侧构建所述凹槽造成的活性材料损失比例为R，R的表达式： 。
在一实施例中，当所述凹槽通过辊压构建时，所述凹槽在所述集流体上的深度满足d≤d 2；其中d为所述凹槽在所述集流体上的深度，d 2为第二涂层的厚度。
在一实施例中，所述集流体（1）的任意一侧构建所述凹槽（4）造成的活性材料损失比例为R，R的表达式： 。
在一实施例中， 0.01%≤R≤20%。
在一实施例中，所述凹槽的宽度小于或等于活性涂层的宽度。
在一实施例中，所述凹槽的长度小于或等于所述集流体的长度。
参阅图1至图10，本申请公开了一种电池极片，所述电池极片包括集流体1、第一涂层2、第二涂层3和至少一个凹槽4，在一些实施例中，所述第一涂层2设置在所述集流体1的任意一侧或两侧，所述第二涂层3层叠设置在所述第一涂层2上，所述凹槽4形成于所述第二涂层3上，其中所述第一涂层2和所述第二涂层3均由活性材料组成。较佳的，通过在所述第二涂层3上设置所述凹槽4，提高电解液对所述电池极片的浸润性及所述电池极片的储液能力，增大所述电池极片活性材料接触反应的面积，缓解所述电池极片膨胀及所述电池极片两侧及中部析锂等，从而改善电池的循环及快充性能。
可选的，所述第二涂层3上设置有一条或者一条以上的所述凹槽4，可选的，所述第二涂层3上的所述凹槽4可根据实际情况而定，通过所述凹槽4储存电解液，提升电解液对所述电池极片的浸润效果及电解液在所述电池极片中的流动速度，从而实现增大所述电池极片表面活性材料的反应面积，缓解所述电池极片两侧及中部析锂，并提供额外的空间便于缓解极片膨胀作用及材料挤压、破碎等情况，以改善电池的循环及快充等性能，延长了电池的循环使用寿命。
可选的，所述第一涂层2和所述第二涂层3层叠设置在所述集流体1的任意一侧或两侧，形成活性涂层。当所述第一涂层2和所述第二涂层3仅层叠设置在所述集流体1的任意一侧时，所述集流体1的另一侧可设置有相应的活性材料，并形成另一活性涂层。
可选的，所述第二涂层3上的所述凹槽4可以通过辊轮辊压成型，较佳的，辊轮上设置有凸起，可选的，辊轮上的凸起可以为多个，较佳的，辊轮上的多个凸起的尺寸大小互不相同，进一步的，辊轮上的多个凸起的设置方向互不相同，可选的，在涂布或者冷压过程中，采用表面设置有不同尺寸大小以及不同设置方向的凸起的辊轮对所述集流体1上的所述第二涂层3进行辊压，以使所述第二涂层3上形成不同尺寸大小以及不同设置方向的多个凹槽4。
可选的，所述第二涂层3上的所述凹槽4可以通过激光灼烧形成，可选的，当活性材料涂布在所述集流体1上，并形成层叠设置的所述第一涂层2和所述第二涂层3后，可通过激光灼烧所述第二涂层3上的活性材料，以在所述第二涂层3上的所述凹槽4；可选的，可以在对涂布在所述集流体1的活性材料进行冷压之后，通过激光灼烧所述第二涂层3上的活性材料，以在所述第二涂层3上的所述凹槽4；可选的，可以在对层叠设置有所述第一涂层2和所述第二涂层3的所述集流体1进行卷绕之前，通过激光灼烧所述第二涂层3上的活性材料，以在所述第二涂层3上的所述凹槽4；进一步的，可通过除尘机等设备对电池极片上经过灼烧后的活性物质进行吸附去除，无需再额外增加清洗极片的工艺。
可选的，所述第二涂层3可涂满在所述第一涂层2远离所述集流体1的一侧，可通过激光刻蚀或辊压在所述第二涂层3上形成所述凹槽4，也即在所述凹槽4的底部可以仍存在第二涂层3，以减少活性材料的损失；可选的，所述第二涂层3可涂布在所述第一涂层2远离所述集流体1的一侧的任意区域，可直接通过双层涂布工艺在所述第二涂层3上形成所述凹槽4，提高所述凹槽4的构建速度，并使所述凹槽4的底部无第二涂层3。
在一些实施例中，所述第一涂层2和所述第二涂层3分别设在所述集流体1的同一侧的不同区域，可选的，所述第一涂层2和所述第二涂层3呈层叠设置，可选的，所述第一涂层2涂布在所述集流体1上，所述第二涂层3涂布在所述第一涂层2上，可选的，所述第一涂层2的面密度大于所述第二涂层3的面密度，且所述凹槽4设置在所述第二涂层3，以避免在所述第二涂层3上开设所述凹槽4后，导致所述集流体1上的活性材料损失过多，对电池额定容量或充电NP比造成较大影响，导致低容或析锂等不良现象出现，严重影响电池的循环性能以及存储性能，也即当所述集流体1的一侧的活性材料的重量处于预设范围时，通过所述第一涂层2的面密度大于所述第二涂层3的面密度，且所述凹槽4设置在所述第二涂层3，能够减少在所述第二涂层3上设置所述凹槽4时造成活性材料的损失量，有效降低在所述第二涂层3设置所述凹槽4对电池的循环性能以及存储性能的影响。
在一些实施例中，电池容量与压实密度呈正相关关系，也即压实密度越大，电池容量越大，可选的，所述第一涂层2的压实密度大于所述第二涂层3的压实密度，以避免在所述第二涂层3上开设所述凹槽4，导致所述集流体1上的活性材料的压实密度产生较大变化，导致电池容量出现明显下降，从而降低在所述第二涂层3上设置所述凹槽4对电池容量的影响。
在一些实施例中，所述第一涂层2的厚度大于所述第二涂层3的厚度。可选的，所述第一涂层2和所述第二涂层3呈层叠设置，并且所述凹槽4设置在所述第二涂层3，以避免开设所述凹槽4，导致所述集流体1上的活性材料损失过多，影响电池的循环性能以及存储性能，也即通过所述第一涂层2的厚度大于所述第二涂层3的厚度，以减少在所述第二涂层3上设置所述凹槽4时造成活性材料的损失量，有效保障在所述第二涂层3设置所述凹槽4后的电池的循环性能以及存储性能。
在一些实施例中，所述第一涂层2和所述第二涂层3分别设在所述集流体1的同一侧的不同区域，可选的，所述第一涂层2和所述第二涂层3呈层叠设置，可选的，所述第一涂层2涂布在所述集流体1上，所述第二涂层3涂布在所述第一涂层2上，其中所述第一涂层2的面密度大于所述第二涂层3的面密度，且所述第一涂层2的厚度大于所述第二涂层3的厚度，进一步的，所述第一涂层2的压实密度大于所述第二涂层3的压实密度，从而充分降低在所述第二涂层3上设置所述凹槽4对所述集流体1上的活性材料的质量、面密度以及压实密度的影响，避免因在所述第二涂层3上设置所述凹槽4而导致电池的容量、循环性能以及存储性能等出现下降情况。
在一些实施例中，电池极片可以为电池正极极片，可选的，活性材料可以由磷酸亚铁锂、三元材料镍钴锰、锰酸锂、钴酸锂和镍钴铝酸锂等中的任意一种或几种的混合物制成；可选的，将由磷酸亚铁锂、三元材料镍钴锰、锰酸锂、钴酸锂和镍钴铝酸锂等中的任意一种或几种的混合物制成的活性材料逐层设置在所述集流体1的同一侧的不同区域，以使所述集流体1上形成呈层叠设置的所述第一涂层2和第二涂层3。
在一些实施例中，电池极片可以为电池负极极片，可选的，活性材料可以由人造石墨、天然石墨、硬碳、软碳和硅中的任意一种或几种的混合物制成，可选的，将由人造石墨、天然石墨、硬碳、软碳和硅等中的任意一种或几种的混合物制成的活性材料逐层设置在所述集流体1的同一侧的不同区域，以使所述集流体1上形成呈层叠设置的所述第一涂层2和第二涂层3。
在一些实施例中，所述第二涂层3上的所述凹槽4可根据实际情况而定，并且需要充分考虑所述凹槽4的宽度、长度及深度，尽可能避免影响电池的额定容量或者充电N/P比，N/P比即电池负极容量和正极容量的比值。
可选的，所述凹槽4的长度小于或等于所述集流体1的长度，可选的，受限于现有加工工艺，所述凹槽4的长度≥0.005mm，也即所述凹槽4的长度当前的最小值可为0.005mm，但伴随着加工工艺以及相应的加工设备的发展，所述凹槽4的长度的最小值可进一步缩小至（0,0.005mm）的范围，可选的，所述凹槽4的长度的最大值等于所述集流体1的长度，限定所述凹槽4不可出现在所述集流体1上，防止后续制程如卷绕中由于张力不均出现极片断带的现象。
可选的，所述凹槽4小于或等于活性涂层的宽度，可选的，受限于现有加工工艺，所述凹槽4的宽度≥0.005mm，也即所述凹槽4的宽度当前的最小值可为0.005mm，但伴随着加工工艺以及相应的加工设备的发展，所述凹槽4的宽度的最小值可进一步缩小至（0,0.005mm）的范围，可选的，所述凹槽4的宽度可以与活性涂层的宽度相等，也即所述凹槽4在MD方向的上的长度可以和极片长度相等，也意味着所述凹槽4可以贯穿所述电池极片的料区，但不能触碰到极耳，若伤到极耳，在后续的卷绕中易出现断带。
可选的，所述集流体1的任意一侧构建所述凹槽4造成的活性材料损失比例为R，较佳的，R的取值范围为[0.01%,20%]，通过限制活性材料损失量来限制所述凹槽4的数量，避免造成所述集流体1上的活性材料损失过多，对电池额定容量或充电NP比造成较大影响，导致低容或析锂等不良现象出现，同时避免所述凹槽4过少，无法有效起到储存电解液、增大反应面积或缓解极片膨胀的效果。较佳的，针对于采用激光刻蚀或者分层涂布工艺构建所述凹槽4，避免现有生产工艺中原本不可避免的活性材料损失影响所述凹槽4的开设，故R需满足≥0.01%，同时避免造成所述集流体1上的活性材料损失过多，对电池额定容量或充电NP比造成较大影响，导致低容或析锂等不良现象出现，故R需满足≤20%；针对于采用辊压工艺构建所述凹槽4，由于通过辊压工艺构建所述凹槽4时，其空间体积必然存在，故R需满足≥0.01%，同时在辊压过程会造成所述凹槽4的底部涂层的压实密度变大，会影响该部分涂层活性材料脱嵌锂的速率，故R需满足≤20%；
可选的，设定所述集流体1上的所述凹槽4的尺寸长宽分别为a 和b；所述凹槽4在所述集流体1上的深度为d；所述集流体1的长度为S；活性涂层（也即所述第一涂层2和所述第二涂层3形成的活性涂层）的宽度为L；d 1为第一涂层料区厚度，d 2为第二涂层料区厚度；M为活性涂层上的活性材料的重量；n为所述集流体1上的凹槽4的数量；P 1为所述集流体1上的正常区域的压实密度，也即所述第一涂层2的压实密度；w1为所述第一涂层2上的活性材料的占比；P 2为所述集流体1上的设置有所述凹槽4区域的压实密度，也即所述第二涂层3的压实密度，可选的，P 1≥P 2；w2为所述第二涂层3上的活性材料的占比；
较佳的，当所述凹槽4通过激光刻蚀或分层涂布构建时，所述凹槽4在所述集流体1上的深度d的表达式如下：
；
当所述凹槽4通过辊压构建时，所述凹槽4在所述集流体1上的深度为d需满足d≤d 2，限定所述凹槽4的深度，防止深度过大导致所述凹槽4底部活性材料压实过大，活性材料被“压死”，无法正常脱嵌锂。
可选的，参阅图3，所述凹槽4的倾斜角度为α；
较佳的，倾斜角度为α的表达式如下：
较佳的，当所述凹槽4通过激光刻蚀或分层涂布构建时，所述凹槽4可设置的比例R的表达式如下：
当所述凹槽4通过辊压构建时，可忽略材料孔隙率，仅通过对所述凹槽4的空间体积进行限定，故所述凹槽4可设置的比例R的表达式如下：
在一些实施例中，所述凹槽4的截面形状并不固定，可选的，所述凹槽4的截面形状可以是矩形、梯形、锥形和弧形等其中的一种；可选的，所述凹槽4分布的位置并不固定，可选的，所述凹槽4在所述第二涂层3上呈均匀分布；可选的，所述凹槽4分布在所述第二涂层3的局部区域；可选的，同一所述第二涂层3的上的所述凹槽4的截面形状同样并不固定，也即同一所述第二涂层3的上的所述凹槽4的截面形状可以为矩形、梯形、锥形和弧形等其中的一种或多种；可选的，同一所述第二涂层3的上的所述凹槽4可以为间隔分布，也即所述凹槽4间相互独立且相互分离，或者所述凹槽4间相互平行，又或者，所述凹槽4为交叉分布，进一步的，所述第二涂层3上既有交叉分布的所述凹槽4，又有间隔分布的所述凹槽4，也即所述凹槽为交叉分布和间隔分布的其中一种或多种。
在一些实施例中，一种电池，包括如上所述的电池极片。
在一些实施例中，所述电池极片的形式一如图1和图2所示，所述第二涂层3上的所述凹槽4沿所述电池极片的TD方向（对应电池的高度方向）呈竖直设置，从而在所述电池极片上构建沿所述电池极片的TD方向的竖直通道，以使所述电池极片能够通过沿所述电池极片的TD方向的竖直通道储存电解液，提升电解液对所述电池极片的浸润效果及电解液在所述电池极片中的流动速度，从而增大所述电池极片表面活性材料的反应面积以及提高反应活性；
在一些实施例中，所述电池极片的形式二如图3所示，所述第二涂层3上的所述凹槽4沿所述电池极片的TD方向（对应电池的高度方向）呈倾斜设置，从而在所述电池极片上构建沿所述电池极片的TD方向的倾斜通道，以使所述电池极片能够通过沿所述电池极片的TD方向的倾斜通道大幅度增加电池极片表面活性材料的反应面积以及储存电解液的能力，提升电解液对所述电池极片的浸润效果及电解液在所述电池极片中的流动速度，同时还可作为气体排出通道，有效降低电池内部的压力，提高电池的安全性能，并且能够缓解所述电池极片间副反应的发生。
在一些实施例中，所述电池极片的形式三如图4所示，所述第二涂层3上的所述凹槽4沿所述电池极片的MD方向（对应电池的宽度方向）呈平直设置，从而在所述电池极片上构建沿所述电池极片的MD方向的平直通道，以使所述电池极片能够通过沿所述电池极片的MD方向的平直通道储存电解液，提升电解液对所述电池极片的浸润效果及电解液在所述电池极片中的流动速度，从而增大所述电池极片表面活性材料的反应面积以及提高反应活性，并且提供额外的空间便于缓解所述电池极片膨胀作用及材料挤压、破碎等情况，同时改善所述电池极片中间与两侧电流不均的现象。
在一些实施例中，所述电池极片的形式四如图5所示，所述第二涂层3上设置有沿所述电池极片的TD方向（对应电池的高度方向）呈竖直设置的所述凹槽4，同时所述第二涂层3上还设置有沿所述电池极片的MD方向（对应电池的宽度方向）呈平直设置的所述凹槽4，从而在所述电池极片上构建沿所述电池极片的TD方向的竖直通道以及沿所述电池极片的MD方向的平直通道，可选的，所述竖直通道与所述平直通道交叉分布设置，以使所述电池极片能够通过沿所述电池极片的TD方向和沿所述电池极片的MD方向交叉分布设置的通道储存电解液，提升电解液对所述电池极片的浸润效果及电解液在所述电池极片中的流动速度，从而增大所述电池极片表面活性材料的反应面积以及提高反应活性，并且提供额外的空间便于缓解所述电池极片膨胀作用及材料挤压、破碎等情况，同时改善所述电池极片中间与两侧电流不均的现象。
在一些实施例中，所述电池极片的形式五如图6所示，所述第二涂层3上设置有沿所述电池极片的TD方向（对应电池的高度方向）呈倾斜设置的所述凹槽4，同时所述第二涂层3上还设置有沿所述电池极片的MD方向（对应电池的宽度方向）呈平直设置的所述凹槽4，从而在所述电池极片上构建沿所述电池极片的TD方向的倾斜通道以及沿所述电池极片的MD方向的平直通道，可选的，所述倾斜通道与所述平直通道交叉分布设置，以使所述电池极片能够通过沿所述电池极片的TD方向和沿所述电池极片的MD方向交叉分布设置的通道大幅度增加电池极片表面活性材料的反应面积以及储存电解液的能力，提升电解液对所述电池极片的浸润效果及电解液在所述电池极片中的流动速度，改善电池的循环及快充等性能，尤其是改善所述电池极片中间与两侧电流不均的现象，同时还可作为气体排出通道，有效降低电池内部的压力，提高电池的安全性能，并且能够缓解所述电池极片间副反应的发生，能够进一步提供额外的空间便于缓解所述电池极片膨胀作用及材料挤压、破碎等情况。
在一些实施例中，所述电池极片的形式六如图7和图8所示，所述第二涂层3上设置有多个沿所述电池极片的TD方向（对应电池的高度方向）呈竖直设置的所述凹槽4，从而在所述电池极片上构建多条沿所述电池极片的TD方向的竖直通道，以使所述电池极片能够通过多个沿所述电池极片的TD方向的竖直通道储存电解液，提升电解液对所述电池极片的浸润效果及电解液在所述电池极片中的流动速度，从而增大所述电池极片表面活性材料的反应面积以及提高反应活性，进一步的，通过分散设置的多个竖直通道提供额外的空间便于缓解所述电池极片膨胀作用及材料挤压、破碎等情况，并且能够降低所述电池极片的阻抗；
可选的，所述第二涂层3上设置有多个沿所述电池极片的MD方向（对应电池的宽度方向）呈平直设置的所述凹槽4，从而在所述电池极片上构建多个沿所述电池极片的MD方向的平直通道，以使所述电池极片能够通过多个沿所述电池极片的MD方向的平直通道储存电解液，提升电解液对所述电池极片的浸润效果及电解液在所述电池极片中的流动速度，从而增大所述电池极片表面活性材料的反应面积以及提高反应活性，同时改善电池的循环及快充等性能，尤其是改善所述电池极片中间与两侧电流不均的现象，进一步的，通过分散设置的多个平直通道提供额外的空间便于缓解所述电池极片膨胀作用及材料挤压、破碎等情况，并且能够降低所述电池极片的阻抗。
在一些实施例中，所述电池极片的形式七如图9所示，所述第二涂层3上设置有沿所述电池极片的TD方向（对应电池的高度方向）设置的所述凹槽4，同时所述第二涂层3上还设置有沿所述电池极片的MD方向（对应电池的宽度方向）设置的所述凹槽4，从而在所述电池极片上构建沿所述电池极片的TD方向设置的通道以及沿所述电池极片的MD方向设置的通道，可选的，沿所述电池极片的TD方向设置的通道可以独立于沿所述电池极片的MD方向设置的通道分布设置，可选的，沿所述电池极片的TD方向设置的通道与沿所述电池极片的MD方向设置的通道呈交叉分布设置，可选的，既有沿所述电池极片的TD方向设置的通道可以独立于沿所述电池极片的MD方向设置的通道分布设置，又有沿所述电池极片的TD方向设置的通道与沿所述电池极片的MD方向设置的通道呈交叉分布设置，以使所述电池极片能够通过沿所述电池极片的TD方向设置的通道和沿所述电池极片的MD方向设置的通道大幅度增加电池极片表面活性材料的反应面积以及储存电解液的能力，提升电解液对所述电池极片的浸润效果及电解液在所述电池极片中的流动速度，改善所述电池极片中间与两侧电流不均的现象，并且能够进一步提供额外的空间便于缓解所述电池极片膨胀作用及材料挤压、破碎等情况。
在一些实施例中，所述电池极片的形式八如图10所示，所述第二涂层3上设置有沿所述电池极片的TD方向（对应电池的高度方向）设置的所述凹槽4，同时所述第二涂层3上还设置有沿所述电池极片的MD方向（对应电池的宽度方向）设置的所述凹槽4，其中沿所述电池极片的TD方向设置的通道与沿所述电池极片的MD方向设置的通道呈交叉分布设置，进一步的，所述第二涂层3上还设置有若干独立于呈交叉分布设置的沿所述电池极片的TD方向设置的通道与沿所述电池极片的MD方向设置的通道的所述凹槽4，从而在所述电池极片上构建呈交叉分布设置的通道以及独立于呈交叉分布设置的通道，以使所述电池极片能够通过上述通道实现储存电解液、提升电解液对所述电池极片的浸润效果及电解液在所述电池极片中的流动速度、增大所述电池极片表面活性材料的反应面积、缓解极片两侧及中部析锂、提供额外的空间便于缓解极片膨胀作用及材料挤压或破碎等情况、改善电池的循环及快充等性能以及降低所述电池极片的阻抗等多种功能。

Claims (15)

  1. 一种电池极片，包括：
    集流体（1）；
    第一涂层（2），所述第一涂层（2）设置在所述集流体（1）的任意一侧或两侧；
    第二涂层（3），所述第二涂层（3）层叠设置在所述第一涂层（2）上；
    至少一个凹槽（4），所述凹槽（4）形成于所述第二涂层（3）上。
  2. 根据权利要求1所述的电池极片，其中：所述第一涂层（2）的面密度大于所述第二涂层（3）的面密度。
  3. 根据权利要求1所述的电池极片，其中：所述第一涂层（2）的压实密度大于所述第二涂层（3）的压实密度。
  4. 根据权利要求1所述的电池极片，其中：所述凹槽（4）沿所述电池极片的TD方向设置或者沿所述电池极片的MD方向设置。
  5. 根据权利要求4所述的电池极片，其中：所述凹槽（4）沿所述电池极片的TD方向呈竖直设置或倾斜设置。
  6. 根据权利要求5所述的电池极片，其中：所述凹槽（4）的倾斜角度为α，α的表达式： ；
    其中S为所述集流体（1）的长度，L为活性涂层的宽度。
  7. 根据权利要求4-6任一项所述的电池极片，其中：所述第二涂层（3）上形成有至少两个所述凹槽（4），所述凹槽（4）为交叉分布和间隔分布的其中一种或多种。
  8. 根据权利要求1-6任一所述的电池极片，其中：当所述凹槽（4）通过激光刻蚀或分层涂布构建时，所述凹槽（4）在所述集流体（1）上的深度为d，d的表达式: ;
    其中a为所述凹槽（4）的长度，b为所述凹槽（4）的宽度，d为所述凹槽（4）在所述集流体（1）上的深度，P 2 为所述第二涂层（3）的压实密度，w 2 为所述第二涂层（3）上的活性材料的占比，d 2 为第二涂层的厚度，S为所述集流体（1）的长度，L为活性涂层的宽度，d 1 为第一涂层的厚度，P 1 为所述第一涂层（2）的压实密度，w 1 为所述第一涂层（2）上的活性材料的占比，M为活性涂层上的活性材料的重量，n为所述集流体（1）上凹槽（4）的数量。
  9. 根据权利要求8所述的电池极片，其中：所述集流体（1）的任意一侧构建所述凹槽（4）造成的活性材料损失比例为R，R的表达式： 。
  10. 根据权利要求1-6任一所述的电池极片，其中：当所述凹槽（4）通过辊压构建时，所述凹槽（4）在所述集流体（1）上的深度满足d≤d 2 ；其中d为所述凹槽（4）在所述集流体（1）上的深度，d 2 为第二涂层的厚度。
  11. 根据权利要求10所述的电池极片，其中：所述集流体（1）的任意一侧构建所述凹槽（4）造成的活性材料损失比例为R，R的表达式： 。
  12. 根据权利要求9或11所述的电池极片，其中：0.01%≤R≤20%。
  13. 根据权利要求8所述的电池极片，其中：所述凹槽（4）的宽度小于或等于活性涂层的宽度。
  14. 根据权利要求8所述的电池极片，其中：所述凹槽（4）的长度小于或等于所述集流体（1）的长度。
  15. 一种电池，包括如权利要求1-14任一项所述的电池极片。
PCT/CN2023/138610 2023-11-16 2023-12-14 一种电池极片及电池 Pending WO2025102469A1 (zh)

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