WO2023078428A1 - 一种极片及电池 - Google Patents

一种极片及电池 Download PDF

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Publication number
WO2023078428A1
WO2023078428A1 PCT/CN2022/130055 CN2022130055W WO2023078428A1 WO 2023078428 A1 WO2023078428 A1 WO 2023078428A1 CN 2022130055 W CN2022130055 W CN 2022130055W WO 2023078428 A1 WO2023078428 A1 WO 2023078428A1
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WO
WIPO (PCT)
Prior art keywords
area
pole piece
coating area
current collector
active material
Prior art date
Application number
PCT/CN2022/130055
Other languages
English (en)
French (fr)
Inventor
邹浒
Original Assignee
珠海冠宇电池股份有限公司
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 珠海冠宇电池股份有限公司 filed Critical 珠海冠宇电池股份有限公司
Priority to EP22889449.9A priority Critical patent/EP4333100A1/en
Priority to JP2023579354A priority patent/JP2024524275A/ja
Priority to KR1020237045395A priority patent/KR20240017862A/ko
Publication of WO2023078428A1 publication Critical patent/WO2023078428A1/zh
Priority to US18/520,379 priority patent/US20240097097A1/en

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    • 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
    • H01M4/04—Processes of manufacture in general
    • H01M4/0402—Methods of deposition of the material
    • H01M4/0404—Methods of deposition of the material by coating on electrode collectors
    • 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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H01M10/0585—Construction or manufacture of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
    • 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
    • H01M10/058—Construction or manufacture
    • H01M10/0587—Construction or manufacture of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
    • 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
    • H01M4/134—Electrodes based on metals, Si or alloys
    • 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
    • H01M4/139—Processes of manufacture
    • 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
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H01M4/665—Composites
    • H01M4/667—Composites in the form of layers, e.g. coatings
    • 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
    • H01M4/64—Carriers or collectors
    • H01M4/70—Carriers or collectors characterised by shape or form
    • 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
    • H01M50/533—Electrode connections inside a battery casing characterised by the shape of the leads or tabs
    • 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
    • H01M50/536—Electrode connections inside a battery casing characterised by the method of fixing the leads to the electrodes, e.g. by welding
    • 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
    • H01M50/538—Connection of several leads or tabs of wound or folded electrode stacks
    • 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
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present application relates to the technical field of batteries, in particular to a pole piece and a battery.
  • lithium batteries As an environmentally friendly green energy, lithium batteries have developed rapidly in recent years. At the same time, consumers have higher and higher performance requirements for lithium batteries, not only requiring lithium batteries to have higher capacity, but also to meet the requirements of charge and discharge rates.
  • connecting the tabs to the middle of the pole piece can reduce the internal resistance and temperature rise of the battery, and increase the charge and discharge rate of the battery.
  • the current collector in the middle of the pole piece is coated with an active material layer, in order to connect the tabs, it is necessary to clean and remove the active material layer on the current collector.
  • the active material on the edge of the slot where the tab is welded and The current collector is cut off together to form a slot with a notch on the pole piece.
  • the present application provides a pole piece and a battery, which are used to at least solve the technical problem that the pole piece is easily broken.
  • the present application provides a pole piece, including: a current collector and an active material layer, the current collector includes a first section, at least one side of the first section is distributed with a first coating area, a second coating area The layout area and the slot area; the second coating area includes a transition area, and the transition area is located between the slot area and the edge of the current collector along the width direction of the current collector; the The active material layer is attached to the surface of the current collector in the first coating area and the second coating area, and the thickness of the active material layer in the second coating area is smaller than that of the first coating area. The thickness of the active material layer in the distribution area.
  • the slot area is used for welding tabs, because the second coating
  • the distribution area includes a transition area, the transition area is located between the slot area and the edge of the current collector, and the thickness of the active material layer in the second coating area is smaller than that in the first coating area. The thickness of the active material layer.
  • Such a structure does not need to cut off the edge of the groove area as in the prior art, so that when the pole piece is slitting and processed, the slitting position can be in the wider transition area, avoiding the groove
  • the bit area is cut, which reduces the difficulty of cutting, can effectively solve the problem of the pole piece band, and avoids the occurrence of the pole piece band that will affect the safety of the battery, and because the second coating area with a smaller thickness is set After welding the tabs, the phenomenon of uneven thickness of the pole piece caused by tab welding can be effectively solved, so that the thickness of the final winding core is uniform, and finally the volume of the processed battery is reduced, and the energy density of the battery is improved.
  • the first coating area extends to the edges of the first section in the length direction and the width direction, and both the slot area and the second coating area are located on the first section The middle of the length direction of a coating area.
  • the ratio of the lengths of the slot region to the transition region is S, where 5 ⁇ S ⁇ 1.
  • the transition zone has a width of 2 mm to 5 mm;
  • the slot area has a width of 9 mm to 30 mm.
  • the second coating area further includes a remaining area, and in the width direction of the current collector, the remaining area is opposite to the position of the transition area, and the The width of the remaining area is 0mm ⁇ 5mm.
  • both sides of the first section are distributed with the first coating area, the second coating area and the slot area, and the first coating area, The distribution positions of the second coating area and the slot area on the two sides of the first section correspond to each other.
  • the surface shape of the active material layer in the second coating area on both sides of the current collector is the same;
  • the surface of the active material layer in the second coating area is planar, wavy, or inclined.
  • a tab is further included, and the tab includes a connecting section and an extending section connected to each other, and the connecting section is connected to one of the slots in the slot area on both sides of the current collector.
  • the location area is fixedly connected, and the extension section extends to the outside of the first coating area along the width direction of the current collector.
  • the thickness of the active material layer attached to the first coating area is 20 ⁇ m to 200 ⁇ m;
  • the thickness of the active material layer attached to the second coating area is 0 ⁇ m to 200 ⁇ m; and/or
  • the thickness of the tab is 100 ⁇ m ⁇ 500 ⁇ m.
  • the present application also provides a battery, including a casing and an electric core accommodated in the casing, the electric core includes a positive electrode sheet, a negative electrode sheet, and a diaphragm spaced between the positive electrode sheet and the negative electrode sheet, the The positive electrode sheet, the negative electrode sheet and the separator are stacked and wound together, and at least one of the positive electrode sheet and the negative electrode sheet is the above-mentioned electrode sheet.
  • the thickness of the active material layer in the second coating area is smaller than that of the active material layer in the first coating area. Thickness, after welding the lugs, it can effectively solve the phenomenon of uneven thickness of the pole piece caused by the welding of the tabs, and finally reduce the volume of the processed battery and increase the energy density of the battery.
  • the slot area and the second coating area are located in the middle of the length direction of the first coating area, after being processed into a battery, is
  • the above-mentioned slot area is used for welding tabs, which facilitates the parallel connection of tabs, reduces the current supplied by the battery, reduces the internal resistance of the battery, and reduces the heat release of the battery. Therefore, when charging or discharging quickly, the heat generation is small. It is beneficial to increase the charge and discharge rate of the battery.
  • Fig. 1 is the structural representation of the pole piece that the embodiment of the present application provides;
  • Figure 2 is a schematic diagram of the A-A cross-sectional structure of Figure 1 of the pole piece provided by the embodiment of the present application;
  • Fig. 3 is another structural schematic diagram of the pole piece provided by the embodiment of the present application.
  • Figure 4 is a schematic diagram of the B-B cross-sectional structure of Figure 3 of the pole piece provided by the embodiment of the present application;
  • Fig. 5 is a schematic structural view of the pole piece strip provided in the embodiment of the present application.
  • Fig. 6 is a schematic structural diagram of the C-C section of Fig. 5 of the pole piece strip provided in the embodiment of the present application;
  • Fig. 7 is another structural schematic diagram of the C-C section of Fig. 5 of the pole piece strip provided in the embodiment of the present application;
  • Fig. 8 is another structural schematic diagram of the C-C section of Fig. 5 of the pole piece strip provided in the embodiment of the present application;
  • Fig. 9 is another structural schematic diagram of the C-C section of Fig. 5 of the pole piece strip provided in the embodiment of the present application;
  • FIG. 10 is another structural schematic diagram of the C-C section of FIG. 5 of the pole piece strip provided in the embodiment of the present application.
  • the tabs are usually welded near the end of the pole piece. After being processed into a battery, multiple tabs are connected in series, which increases the internal resistance of the battery and causes a large amount of heat generated by the battery. , affect the application of the battery in the field of fast charging.
  • the tabs can be welded near the middle of the pole piece, and the tabs are connected in parallel. In this way, the battery can be reduced.
  • the internal resistance of the battery reduces the calorific value of the battery, which is conducive to increasing the charge and discharge rate of the battery.
  • the tabs near the middle of the pole piece will easily cause uneven thickness distribution of the pole piece, which will affect the flatness of the battery core after being wound into the battery core, and will easily cause the thickness of the battery to increase.
  • the active material at the position where the tab is welded on the pole piece is cut off together with the current collector, so as to create a slot with a gap to weld the tab. Influenced by the impact, the offset of the position of the slitting line will easily lead to the problem of pole piece strips, which will affect the safety of the battery.
  • the pole piece and the battery provided by the present application, by improving the structure of the pole piece, set the first coating area, the second coating area and the slot area, and the slot area is used for welding the tabs, because The transition area of the second coating area is connected between the slot area and the edge of the first coating area, and the thickness of the active material layer in the second coating area is smaller than the thickness of the active material layer in the first coating area , With such a structure, there is no need to cut off the edge of the slot area, so that when the pole piece is cut and processed, the problem of the pole piece strip can be effectively solved, and the poor processing of the pole piece will be avoided, which will affect the safety of the battery.
  • the present application provides a pole piece, including: a current collector 10 and an active material layer 20, the current collector 10 includes a first segment 11, at least one side of the first segment 11 is distributed with a first coating Zone 31, second coating zone 32 and slot zone 33.
  • the current collector 10 is in the shape of a sheet, and the direction indicated by X is the length direction of the first coating area 31, that is, the length direction of the current collector 10; the direction indicated by Y is the width direction of the first coating area 31, that is The width direction of the current collector 10 .
  • the first coating area 31 extends to the edge of the length direction and the width direction of the first section 11, that is, the length of the first coating area 31 is equal to the length of the first section 11, and the width of the first coating area 31 is equal to that of the first section. 11 are equal in width.
  • both ends of the slot area 33 and both ends of the second coating area 32 are joined to the first coating area 31 respectively.
  • the second coating area 32 includes a transition area 321 , and along the width direction of the current collector 10 , the transition area 321 is located between the slot area 33 and the edge of the current collector 10 .
  • No active material layer 20 is attached to the surface of the current collector 10 in the slot area 33, and the active material layer 20 is attached to the surface of the current collector 10 in the first coating area 31 and the second coating area 32, and the second coating area
  • the thickness of the active material layer 20 in 32 is smaller than the thickness of the active material layer 20 in the first coating area 31 .
  • a pole piece provided by the present application by setting the first coating area 31, the second coating area 32 and the slot area 33, as shown in Figure 3 and Figure 4, the slot area 33 is used for welding the tab 50, Since the second coating area 32 includes a transition area 321, the transition area 321 is located between the edge of the slot area 33 and the current collector 10. With such a structure, it is not necessary to cut off the edge of the slot area 33, so that in the cutting processing pole It can effectively solve the problem of the pole piece broken belt, and avoid the poor processing of the pole piece, which will affect the safety of the battery.
  • the thickness of the active material layer 20 in the second coating area 32 is smaller than the thickness of the active material layer 20 in the first coating area 31, and since the second coating area 32 is provided, After the tab 50 is welded in the slot area 33, the uneven thickness of the pole piece caused by the welding of the tab 50 can be effectively solved, which is conducive to improving the smoothness of the surface of the battery cell caused by the pole piece structure, and finally improving the energy density of the battery.
  • both the slot area 33 and the second coating area 32 are located in the middle of the length direction of the first coating area 31, such a pole piece structure, in After being processed into a battery, the slot area 33 is used for welding the tabs 50, which facilitates the parallel connection of the tabs 50, reduces the current supplied by the battery, reduces the internal resistance of the battery, and reduces the heat release of the battery, so when charging and discharging , heat generation is small, which is conducive to improving the battery charge and discharge rate.
  • the ratio of the length of the slot region 33 to the length of the transition region 321 is S, where 5 ⁇ S ⁇ 1.
  • the slot area 33 can be longer than the transition area 321 to ensure that there is enough space in the slot area 33 to weld the tab 50, by controlling the ratio S of the length of the slot area 33 to the length of the transition area 321 to be less than or equal to 5, It can also prevent the energy density of the battery from being affected by too long slot area 33 .
  • the length direction of the slot area 33 and the length direction of the transition area 321 are consistent with the length direction of the current collector 10 .
  • the ratio S of the length of the slot region 33 to the length of the transition region 321 may be 1, 2, 3, 4 or 5 along the length direction of the current collector 10 .
  • the width of the transition region 321 is 2 mm ⁇ 5 mm.
  • the width direction of the transition region 321 and the width of the slot region 33 are both consistent with the width direction of the current collector 10 .
  • the width of the transition region 321 may be 2 mm, 3 mm, 4 mm or 5 mm.
  • the slot area 33 has a width of 9 mm to 30 mm.
  • the slot area 33 may have a width of 9 mm, 10 mm, 15 mm, 20 mm, 25 mm or 30 mm.
  • the length of the slot area 33 can be 12mm
  • the width of the tab 50 can be 4mm, 5mm or 6mm
  • the length of the transition zone 321 can be the same as the width of the tab 50, that is, 4mm, 5mm or 6mm.
  • the second coating area 32 further includes a remaining area 322, and along the width direction of the current collector 10, the gap between the remaining area 322 and the transition area 321 The positions are opposite, and the width of the remaining area 322 is 0mm ⁇ 5mm. The width direction of the remaining area 322 is consistent with the width direction of the current collector 10 .
  • the pole piece may include a remaining area 322, and the width of the remaining area 322 may be 1 mm, 2 mm, 3 mm, 4 mm or 5 mm; of course, the pole piece may not include the remaining area 322, That is, the width of the remaining area 322 is 0 mm. Whether the pole piece includes the remaining area 322 depends on the cutting position of the cutting line 60 .
  • the length of the remaining area 322 can be equal to the length of the transition area 321.
  • the remaining area 322 of the pole piece is connected to the transition area 321 of another adjacent pole piece in one piece. After slitting, the remaining area 322 of the pole piece is separated from the transition area 321 of another adjacent pole piece, thereby further improving the cutting and preparation efficiency of the pole piece, while ensuring that the battery loaded with the pole piece energy density.
  • the active material layer 20 is attached to the surface of the current collector 10 in the remaining area 322 .
  • Both the remaining area 322 and the transition area 321 are located in the middle of the length direction of the first coating area 31, and the positions of the remaining area 322 and the transition area 321 in the length direction of the first coating area 31 are the same, and the remaining area 322 and the transition area 321 is opposite to the position of the first coating area 31 along the width direction of the first coating area 31 , and the remaining area 322 and the transition area 321 may be respectively located at both ends of the width direction of the first coating area 31 .
  • the above-mentioned pole piece further includes a tab 50, and the tab 50 includes a connecting section 51 and an extending section 52 connected to each other, and the connecting section 51 and the slot area 33 is fixedly connected, and the extension section 52 is along the width direction of the current collector 10 and extends to the outside of the first coating area 31 through the transition area 321 .
  • connection section 51 is welded to the slot area 33 , and the connection between the tab 50 and the slot area 33 may be achieved by laser welding.
  • the extension section 52 is a part connected to the connection section 51, the extension section 52 is used to extend the side of the pole piece to connect with the positive end or the negative end of the battery, and the extension section 52 extends to the first coating through the transition zone 321 Outside the area 31 , the protruding section 52 may be attached to the surface of the transition area 321 and extend to the outside of the first coating area 31 .
  • the thickness of the protruding section 52 is superimposed on the thickness of the active material layer 20 coated in the transition zone 321, it is less than or equal to the thickness of the active material layer 20 in the first coating zone 31, This ensures that the local thickness of the pole piece will not be thickened due to welding the tab 50, and the thickness distribution of the pole piece is uniform.
  • the flatness of the battery can avoid the increase in the volume of the battery cell and affect the energy density of the battery.
  • the thickness of the protruding section 52 is superimposed on the thickness of the active material layer 20 coated in the transition zone 321, it is higher than the thickness of the active material layer 20 in the first coating zone 31, but Since the thickness of the active material layer 20 in the transition zone 321 is smaller than the thickness of the active material layer 20 in the first coating zone 31, it is also conducive to pole piece welding of the tab 50 relative to the pole piece structure without the transition zone 321. The subsequent thickness is uniformly distributed. Compared with the pole piece structure without the transition zone 321, the problem of strip breakage of the pole piece can be avoided, and the thickness of the battery cell made by winding the pole piece can be reduced to a certain extent, avoiding damage to the battery. The energy density has an adverse effect.
  • the first coating area 31, the second coating area 32 and the slot area 33 are distributed on one side of the first section 11, and the other side of the first section 11 is all the first coating area. 31. Not shown in the figure.
  • a first coating area 31, a second coating area 32 and a slot area 33 are distributed on both sides of the first section 11, and the first coating area
  • the distribution positions of the cloth area 31 , the second coating area 32 and the slot area 33 on both sides of the first section 11 correspond to each other.
  • Such a structure makes the position corresponding to the back of the slot area 33 also the slot area 33 , and the stress of the pole piece can be reduced when the tab 50 is welded.
  • the tab 50 is connected to one of the slot areas 33 on both sides of the current collector 10 .
  • the connection section 51 which may be the tab 50 is welded to the slot area 33 on one side of the current collector by means of laser welding.
  • the thickness of the active material layer 20 in the second coating area 32 is distributed in a gradually increasing and decreasing gradient along the width direction of the first coating area 31 .
  • the thickness of the active material layer 20 in the second coating area 32 is uniform.
  • the active material layer 20 in the second coating area 32 may be uniformly coated first, and then removed in a gradient along the thickness direction of the second coating area 32 .
  • the surface of the active material layer 20 in the second coating area 32 is wavy, that is, the active material layer 20 in the second coating area 32 can be waved. shaped blocks.
  • the surface of the active material layer 20 in the second coating area 32 is inclined, that is, the active material layer 20 in the second coating area 32 can be triangular. Lumpy.
  • the surface of the active material layer 20 in the second coating area 32 is planar, that is, the active material layer 20 in the second coating area 32 can be in the shape of a rectangular block. shape.
  • the surface shape of the active material layer 20 in the second coating area 32 on both sides of the current collector 10 is the same or different, that is, the second coating area 32 distributed on both sides of the first section 11
  • the inner active material layers 20 may have the same or different shapes.
  • the active material layers 20 in the second coating area 32 distributed on both sides of the first section 11 can all be in the shape of a rectangular block or all have a wavy surface, or all have a surface with a wavy surface. Inclined. Referring to Fig. 8 and Fig.
  • the active material layer 20 in the second coating area 32 distributed on one side of the first segment 11 can be in the shape of a rectangular block, and the active material layer 20 in the second coating area 32 distributed on the other side
  • the active material layer 20 may have a wavy surface, or the active material layer 20 in the second coating area 32 distributed on the other side may also have an inclined surface.
  • the size of the second coating area 32 and the size of the slot area 33 of the pole piece can be adjusted according to the size of the battery.
  • the current collector 10 further includes a second segment 12 connected to at least one end of the first segment 11 , and no active material layer 20 is attached to the surface of the second segment 12 .
  • the above-mentioned pole piece may be a positive pole piece, or may be a negative pole piece.
  • the material of the current collector 10 in the positive electrode sheet and the negative electrode sheet can be set according to actual needs, and no further limitation is made here.
  • the current collector 10 in the positive electrode sheet can be aluminum foil
  • the current collector 10 in the negative electrode sheet can be copper foil.
  • the type and proportion of the active material in the active material layer 20 in the positive electrode sheet and the negative electrode sheet can also be set according to actual needs, and no further limitation is made here.
  • the active material in the active material layer 20 in the negative electrode sheet can include materials such as graphite, hard carbon, silicon, silicon oxide, and the active material in the active material layer 20 in the positive electrode sheet can include lithium cobaltate, lithium iron phosphate, Lithium manganese oxide and other materials.
  • the present application also provides a pole piece material strip, including the above-mentioned pole piece, and several pole pieces are sequentially connected along the width direction of the current collector 10, and the first section 11 of the pole piece is connected with the adjacent pole pieces.
  • the first section 11 of the pole piece is connected, and the second section 12 of the pole piece is connected with the second section 12 of the adjacent pole piece.
  • the pole sheet strip is the material for processing the pole piece.
  • the surface of the pole piece strip is usually coated with the active material layer 20 and then the pole piece is cut.
  • the slitting line 60 on the pole piece strip is cut, so that the pole piece strip is cut into several pole pieces.
  • the slitting line 60 is a virtual line extending along the length direction of the pole piece. After the slitting is completed, the pole piece strips on both sides of the slitting line 60 become two independent pole pieces.
  • the remaining area 322 of the second coating area 32 of the pole piece is connected with the transition area 321 of the second coating area 32 of the adjacent pole piece.
  • the cutting line 60 cuts the second coating area 32 into a remaining area 322 and a transition area 321 respectively located on two different pole pieces , and since the surface of the current collector 10 in the remaining area 322 and the transition area 321 is coated with the active material layer 20, it is possible to avoid the removal of grooves on the first section 11 of the pole piece due to the cutting error of the pole piece strip. Parts other than the bit area 33 expose the surface of the current collector 10 to avoid affecting the quality and safety performance of the battery.
  • the thickness of the active material layer 20 attached to the first coating area 31 is 20 ⁇ m to 200 ⁇ m; and/or, the thickness of the active material layer 20 attached to the second coating area 32 is 0 ⁇ m to 200 ⁇ m .
  • the average thickness of the active material layer 20 attached to the first coating area 31 may be 20 ⁇ m, and the average thickness of the active material layer 20 attached to the second coating area 32 may be 10 ⁇ m;
  • the average thickness of the active material layer 20 is 100 ⁇ m, and the average thickness of the active material layer 20 attached to the second coating area 32 is 50 ⁇ m or 80 ⁇ m; it can also be that the average thickness of the active material layer 20 attached to the first coating area 31 is 200 ⁇ m, the average thickness of the active material layer 20 attached to the second coating area 32 is 70 ⁇ m or 100 ⁇ m. It is satisfied that the thickness of the active material layer 20 in the second coating area 32 is smaller than the thickness of the active material layer 20 in the first coating area 31 .
  • the thickness of the tab 50 is 100 ⁇ m ⁇ 500 ⁇ m.
  • the average thickness of the tab 50 may be 100 ⁇ m, 200 ⁇ m, 300 ⁇ m, 400 ⁇ m or 500 ⁇ m.
  • the surface of the current collector 10 in the transition region 321 and the remaining region 322 is coated with the active material layer 20, even if it is affected by the slitting error and causes the separation
  • the tangent 60 is offset upwards or downwards along the width direction of the current collector 10, and the final result is that the area size of the transition zone 321 and the residual zone 322 connected to the transition zone 321 changes, without causing residual
  • the exposure of the current collector 10 in the remaining area 322 will not cause a gap at the position of the remaining area 322 , thereby ensuring that the problem of pole piece bands is avoided.
  • the slitting of the pole piece strip can be realized by a sheet making machine or an integrated sheet making and winding machine, or the pole piece in this embodiment can be processed by laser slitting.
  • the present application also provides a battery, including a casing and an electric core housed in the casing.
  • the electric core includes a positive electrode sheet, a negative electrode sheet, and a separator spaced between the positive electrode sheet and the negative electrode sheet.
  • the positive electrode sheet, the negative electrode sheet, and the separator are laminated. After being wound together, at least one of the positive electrode sheet and the negative electrode sheet is the above-mentioned electrode sheet.
  • the positive electrode sheet can be the above-mentioned electrode sheet, and the negative electrode sheet can be a conventional electrode sheet; or the negative electrode sheet can be the above-mentioned electrode sheet, and the positive electrode sheet can be a conventional electrode sheet; Of course, it is also possible that both the positive electrode sheet and the negative electrode sheet are the above-mentioned electrode sheets.
  • the surface of the battery cell has better flatness, and the stress uniformity on the surface of the pole piece during the cycle charge and discharge process of the battery is better, which improves the service life of the battery , which is beneficial to increase the charge and discharge rate of the battery.
  • the separator separates the positive electrode and the negative electrode to prevent the short circuit caused by the contact between the positive electrode and the negative electrode.
  • the separator also has the function of allowing the electrolyte ions in the electrolyte to pass through.
  • the separator can include a substrate and a coating layer, wherein the substrate can be a polyethylene (polythene, PE) monolayer film, a polypropylene (polypropylene, PP) monolayer film or a polypropylene-polyethylene-polypropylene three-layer composite film,
  • the coating layer may be at least one of porous silica, alumina, titania and zirconia.
  • the casing is also filled with electrolyte, and the battery core is immersed in the electrolyte.
  • the above-mentioned electric core may be an electric core with a winding structure.
  • the aforementioned battery may be a pouch battery, an aluminum case battery or a cylindrical battery.
  • first and second are used for descriptive purposes only, and cannot be interpreted as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features. Thus, a feature defined as “first” and “second” may explicitly or implicitly include one or more of these features.
  • “plurality” means at least two, such as two, three, etc., unless otherwise specifically defined.
  • connection should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection, or Become one; it can be mechanically connected, or electrically connected, or can communicate with each other; it can be directly connected, or indirectly connected through an intermediary, and it can make the internal communication of two components or the interaction relationship between two components.
  • connection can be a fixed connection or a detachable connection, or Become one; it can be mechanically connected, or electrically connected, or can communicate with each other; it can be directly connected, or indirectly connected through an intermediary, and it can make the internal communication of two components or the interaction relationship between two components.
  • a first feature being "on” or “under” a second feature may include direct contact between the first and second features, and may also include the first and second features Not in direct contact but through another characteristic contact between them.
  • “above”, “above” and “above” the first feature on the second feature include that the first feature is directly above and obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature.
  • “Below”, “beneath” and “under” the first feature to the second feature include that the first feature is directly below and obliquely below the second feature, or simply means that the first feature has a lower level than the second feature.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Composite Materials (AREA)
  • Connection Of Batteries Or Terminals (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Secondary Cells (AREA)

Abstract

本申请提供一种极片及电池，其中，本申请提供的一种极片，包括：集流体和活性物质层，所述集流体包括第一段，所述第一段的至少一面分布有第一涂布区、第二涂布区和槽位区；所述第二涂布区包括过渡区，且在沿所述集流体的宽度方向，所述过渡区位于所述槽位区和所述集流体的边沿之间；所述活性物质层附着于所述第一涂布区和所述第二涂布区内的所述集流体表面，且所述第二涂布区内的所述活性物质层的厚度小于所述第一涂布区内的所述活性物质层的厚度。本申请用以至少解决极片易断带的技术问题。

Description

一种极片及电池
本申请要求于2021年11月04日提交中国专利局、申请号为202122693996.7、申请名称为“一种极片及电池”的中国专利申请的优先权，其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，尤其涉及一种极片及电池。
背景技术
锂电池作为环保型绿色能源，近年来得到了迅速发展，与此同时，消费者对锂电池的性能要求也越来越高，不仅要求锂电池具有较高的容量，还要满足充放电倍率要求。
锂电池中，将极耳连接在极片中部位置上，可以减小电池的内阻和温升，达到提升电池充放电倍率的作用。考虑到极片中部的位置的集流体上涂布有活性物质层，为了连接极耳，需要清洗去除集流体上的活性物质层，相关技术中，将焊接极耳的槽位边缘的活性物质和集流体一起切除，在极片上形成一个带缺口的槽位，但是在现有技术的分切过程中，容易造成极片断带，影响加工的电池品质。
因此，急需解决发展一种极片及电池，解决极片易断带的技术问题。
发明内容
本申请提供一种极片及电池，用以至少解决极片易断带的技术问题。
为了实现上述目的，本申请提供一种极片，包括：集流体和活性物质层，所述集流体包括第一段，所述第一段的至少一面分布有第一涂布区、第二涂布区和槽位区；所述第二涂布区包括过渡区，在沿所述集流体的宽度方向，所述过渡区位于所述槽位区和所述集流体的边沿之间；所述活性物质层附着于所述第一涂布区和所述第二涂布区内的所述集流体表面，所述第二涂布区 内的所述活性物质层的厚度小于所述第一涂布区内的所述活性物质层的厚度。
本申请提供的一种极片，通过设置所述第一涂布区、所述第二涂布区和所述槽位区，所述槽位区用于焊接极耳，由于所述第二涂布区包括过渡区，所述过渡区位于所述槽位区和所述集流体的边沿之间，所述第二涂布区内的活性物质层的厚度小于所述第一涂布区内的活性物质层的厚度。这样的结构，无需如现有技术般，分切时切除所述槽位区边缘的部分，使得在分切加工极片时，分切位置可以处于较宽的所述过渡区，避免所述槽位区被分切，减小了分切的难度，可以有效解决极片断带的问题，避免了出现极片断带导致影响电池的使用安全性，并且由于设置了厚度较小的第二涂布区，焊接极耳之后，可以有效解决极耳焊接造成极片厚度不均匀的现象，使得最终的卷芯的厚度均匀，最终减小加工成的电池体积，提高电池的能量密度。
在一种可能实施的方式中，所述第一涂布区延伸到所述第一段的长度方向和宽度方向的边缘，所述槽位区和所述第二涂布区均位于所述第一涂布区的长度方向的中部。
在一种可能实施的方式中，在沿所述集流体的长度方向，所述槽位区和所述过渡区的长度的比值为S，其中，5≥S≥1。
在一种可能实施的方式中，在沿所述集流体的宽度方向上，所述过渡区的宽度为2mm～5mm；和/或
在沿所述集流体的宽度方向上，所述槽位区的宽度为9mm～30mm。
在一种可能实施的方式中，所述第二涂布区还包括余留区，在沿所述集流体的宽度方向上，所述余留区与所述过渡区的位置相对，且所述余留区的宽度为0mm～5mm。
在一种可能实施的方式中，所述第一段的两面均分布有所述第一涂布区、所述第二涂布区和所述槽位区，且所述第一涂布区、所述第二涂布区和所述槽位区在所述第一段的两面的分布位置分别相互对应。
在一种可能实施的方式中，所述集流体两面的所述第二涂布区内的所述活性物质层的表面形状相同；或
所述集流体两面的所述第二涂布区内的所述活性物质层的表面形状不同。
在一种可能实施的方式中，所述第二涂布区内的所述活性物质层的表面呈平面状、波浪面状、或倾斜状。
在一种可能实施的方式中，还包括极耳，所述极耳包括相互连接的连接段和伸出段，所述连接段与所述集流体两面的所述槽位区中的一个所述槽位区连接固定连接，所述伸出段沿所述集流体的宽度方向，延伸到所述第一涂布区的外侧。
在一种可能实施的方式中，所述第一涂布区附着的所述活性物质层的厚度为20μm～200μm；和/或
所述第二涂布区附着的所述活性物质层的厚度为0μm～200μm；和/或
所述极耳的厚度为100μm～500μm。
本申请还提供一种电池，包括壳体和容置在壳体内的电芯，所述电芯包括正极片、负极片和间隔在所述正极片和所述负极片之间的隔膜，所述正极片、所述负极片和所述隔膜层叠后卷绕在一起，所述正极片和所述负极片中的至少一者为上述的极片。
本申请提供的极片，由于设置了所述第二涂布区，所述第二涂布区内的所述活性物质层的厚度小于所述第一涂布区内的所述活性物质层的厚度，焊接极耳之后，可以有效解决极耳焊接造成极片厚度不均匀的现象，最终减小加工成的电池体积，提高电池的能量密度。
本申请提供的极片及电池，由于所述槽位区和所述第二涂布区均位于所述第一涂布区长度方向的中部，这样的极片结构，在加工成电池之后，所述槽位区用于焊接极耳，便于实现极耳的并联，可以减小电池供电的电流，减小电池的内阻，电池的放热少，因而在快速充电或者放电时，产热小，有利于提升电池充放电倍率。
除了上面所描述的本申请实施例解决的技术问题、构成技术方案的技术特征以及由这些技术方案的技术特征所带来的有益效果外，本申请实施例提供的一种极片及电池所能解决的其他技术问题、技术方案中包含的其他技术特征以及这些技术特征带来的有益效果，将在具体实施方式中作进一步详细的说明。
附图说明
为了更清楚地说明本申请实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作以简单地介绍，显而易见地，下 面描述中的附图是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动性的前提下，还可以根据这些附图获得其他的附图。
图1为本申请实施例提供的极片的结构示意图；
图2为本申请实施例提供的极片的图1的A-A截面结构示意图；
图3为本申请实施例提供的极片的又一结构示意图；
图4为本申请实施例提供的极片的图3的B-B截面结构示意图；
图5为本申请实施例提供的极片料带的结构示意图；
图6为本申请实施例提供的极片料带的图5的C-C截面的结构示意图；
图7为本申请实施例提供的极片料带的图5的C-C截面的又一结构示意图；
图8为本申请实施例提供的极片料带的图5的C-C截面的又一结构示意图；
图9为本申请实施例提供的极片料带的图5的C-C截面的又一结构示意图；
图10为本申请实施例提供的极片料带的图5的C-C截面的又一结构示意图。
附图标记说明：
10-集流体；
20-活性物质层；
11-第一段；
12-第二段；
31-第一涂布区；
32-第二涂布区；
321-过渡区；
322-余留区；
33-槽位区；
50-极耳；
51-连接段；
52-伸出段；
60-分切线。
具体实施方式
为使本申请的目的、技术方案和优点更加清楚，下面将结合本申请中的附图，对本申请中的技术方案进行清楚、完整地描述，显然，所描述的实施例是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本申请保护的范围。
电池结构中，通常是将极耳焊接在极片靠近端部的位置，加工成电池之后，多个极耳之间为串联的方式连接，因而造成电池的内阻增大，导致电池发热量大，影响电池在快充领域的应用，为了减小电池的内阻和温升的问题，可以将极耳焊接在极片靠近中部的位置，极耳之间采用并联的方式连接，这样，可以降低电池的内阻，降低电池的发热量，有利于提高电池充放电倍率。
但是将极耳焊接在极片靠近中部的位置，容易造成极片的厚度分布不均匀，最终卷绕成电芯后影响电芯的平整性，容易造成电池的厚度增大，为了改善极片的厚度分布，相关技术中将极片上焊接极耳的位置的活性物质带集流体一起切除，从而制造一个带缺口的槽位来焊接极耳，这样的结构在极片分切步骤时，由于切割误差的影响，分切线位置发生偏移会容易出现极片断带的问题，影响电池的使用安全性。
鉴于上述背景，本申请提供的极片及电池，通过对极片的结构做出改进，设置第一涂布区、第二涂布区和槽位区，槽位区用于焊接极耳，由于第二涂布区的过渡区连接在槽位区和第一涂布区的边沿之间，且第二涂布区内的活性物质层的厚度小于第一涂布区内的活性物质层的厚度，这样的结构，无需再切除槽位区边缘的部分，使得在分切加工极片时，可以有效解决极片断带的问题，避免了出现极片加工不良导致影响电池的使用安全性。
下面参考附图描述本申请实施例提供的极片及电池。
参考图1和图2所示，本申请提供一种极片，包括：集流体10和活性物质层20，集流体10包括第一段11，第一段11的至少一面分布有第一涂布区31、第二涂布区32和槽位区33。
参考图1所示，集流体10呈薄片状，X表示的方向为第一涂布区31长度方向，即集流体10的长度方向；Y表示的方向为第一涂布区31宽度方向， 即集流体10的宽度方向。第一涂布区31延伸到第一段11的长度方向和宽度方向的边缘，即，第一涂布区31长度与第一段11的长度相等，第一涂布区31宽度与第一段11的宽度相等。在一个具体示例中，槽位区33的两端以及第二涂布区32的两端分别与第一涂布区31相拼接。
参考图1和图2所示，第二涂布区32包括过渡区321，且在沿集流体10的宽度方向，过渡区321位于槽位区33和集流体10的边沿之间。
槽位区33内的集流体10表面均未附着活性物质层20，活性物质层20附着于第一涂布区31和第二涂布区32内的集流体10表面，且第二涂布区32内的活性物质层20的厚度小于第一涂布区31内的活性物质层20的厚度。
本申请提供的一种极片，通过设置第一涂布区31、第二涂布区32和槽位区33，参考图3和图4所示，槽位区33用于焊接极耳50，由于第二涂布区32包括过渡区321，过渡区321位于槽位区33和集流体10的边沿之间，这样的结构，无需再切除槽位区33边缘的部分，使得在分切加工极片时，可以有效解决极片断带的问题，避免了出现极片加工不良导致影响电池的使用安全性。
本申请提供的一种极片，第二涂布区32内的活性物质层20的厚度小于第一涂布区31内的活性物质层20的厚度，并且由于设置了第二涂布区32，在槽位区33焊接极耳50之后，可以有效解决极耳50焊接造成极片厚度不均匀的现象，有利于改善极片结构引起的电芯表面的平整性，最终提高电池的能量密度。
在一种可能实施的方式中，参考图1和图3所示，槽位区33和第二涂布区32均位于第一涂布区31的长度方向的中部，这样的极片结构，在加工成电池之后，槽位区33用于焊接极耳50，便于实现极耳50的并联，可以减小电池供电的电流，减小电池的内阻，电池的放热少，因而在充放电时，产热小，有利于提升电池充放电倍率。
在一种可能实施的方式中，在沿集流体10的长度方向，槽位区33的长度和过渡区321的长度的比值为S，其中，5≥S≥1。槽位区33可以比过渡区321长一些，以确保槽位区33内有足够的位置来焊接极耳50，通过控制槽位区33的长度和过渡区321的长度的比值S小于等于5，也能够避免槽位区33过长影响到电池的能量密度。其中，槽位区33的长度方向和过渡区321 的长度方向与集流体10的长度方向一致。
在一种可能实施的方式中，在沿集流体10的长度方向，槽位区33的长度和过渡区321的长度的比值S可以为1、2、3、4或5。
在一种可能实施的方式中，在沿集流体10的宽度方向上，过渡区321的宽度为2mm～5mm。过渡区321的宽度方向和槽位区33的宽度均与集流体10的宽度方向一致。
在一种可能实施的方式中，在沿集流体10的宽度方向上，过渡区321的宽度可以为2mm、3mm、4mm或5mm。
在一种可能实施的方式中，在沿集流体10的宽度方向上，槽位区33的宽度为9mm～30mm。
在一种可能实施的方式中，在沿集流体10的宽度方向上，槽位区33的宽度可以为9mm、10mm、15mm、20mm、25mm或30mm。
容易理解的是，为了确保极耳50的焊接效果，槽位区33内的集流体10表面未附着活性物质层20，槽位区33的长度大于极耳50的宽度，以确保槽位区33有足够的位置来焊接极耳50。例如，槽位区33的长度可以为12mm，极耳50的宽度可以为4mm、5mm或6mm，过渡区321的长度可以与极耳50的宽度相同，即为4mm、5mm或6mm，在槽位区33焊接极耳50时，有足够安全的距离可以避免极耳50焊接到附着活性物质层20的位置。
在一种可能实施的方式中，参考图1和图3所示，第二涂布区32还包括余留区322，在沿集流体10的宽度方向上，余留区322与过渡区321的位置相对，余留区322的宽度为0mm～5mm。余留区322的宽度方向与集流体10的宽度方向一致。
在一种可能实施的方式中，极片中可以包括余留区322，余留区322的宽度可以为1mm、2mm、3mm、4mm或5mm；当然极片中也可以不包括余留区322，即余留区322的宽度0mm。极片中是否包括余留区322，取决于分切线60的分切位置。
余留区322的长度可以与过渡区321的长度相等，在极片分切之前，极片的余留区322与相邻的另一个极片的过渡区321为一体连接的状态，在极片分切之后，极片的余留区322与相邻的另一个极片的过渡区321被分切开来，从而进一步提高极片的分切和制备效率，同时保证装载有该极片的电池 的能量密度。
容易理解的是，参考图1和图6所示，余留区322内的集流体10表面均附着活性物质层20。余留区322与过渡区321均位于第一涂布区31长度方向的中部，且余留区322与过渡区321在第一涂布区31长度方向的位置相同，余留区322与过渡区321在第一涂布区31沿第一涂布区31的宽度方向上的位置相对，可以是余留区322与过渡区321分别位于第一涂布区31的宽度方向的两端。
在一种可能实施的方式中，参考图3和图4所示，上述的极片还包括极耳50，极耳50包括相互连接的连接段51和伸出段52，连接段51与槽位区33固定连接，伸出段52沿集流体10的宽度方向，并通过过渡区321延伸到第一涂布区31的外侧。
在一种可能实施的方式中，连接段51与槽位区33焊接连接，可以是通过激光焊接的方式实现极耳50与槽位区33的连接。
伸出段52为与连接段51连接的部分，伸出段52用于伸出极片的侧边与电池的正极端或负极端连接，伸出段52通过过渡区321延伸到第一涂布区31的外侧，可以是伸出段52贴合在过渡区321的表面延伸到第一涂布区31的外侧。
在一种可能实施的方式中，伸出段52的厚度与过渡区321内涂布的活性物质层20的厚度叠加之后，小于或等于第一涂布区31内的活性物质层20的厚度，这样确保不会由于焊接了极耳50，导致极片的局部厚度增厚，极片的厚度分布均匀，在将极片卷绕制成电芯之后，有利于改善极片结构引起的电芯表面的平整性，避免造成电芯的体积增大，影响电池的能量密度。
在一种可能实施的方式中，伸出段52的厚度与过渡区321内涂布的活性物质层20的厚度叠加之后，高于第一涂布区31内的活性物质层20的厚度，但是由于过渡区321内的活性物质层20的厚度小于第一涂布区31内的活性物质层20的厚度，这样相对于不设置过渡区321的极片结构，也是有利于极片焊接极耳50之后的厚度均匀分布，相对于不设置过渡区321的极片结构既能够避免极片发生断带的问题，也能够在一定程度上减小极片卷绕制成的电芯厚度，避免对电池的能量密度造成不利的影响。
在一种可能实施的方式中，第一段11的一面分布有第一涂布区31、第 二涂布区32和槽位区33，第一段11的另一面全部为第一涂布区31。图中未示出。
在一种可能实施的方式中，参考图1和图6所示，第一段11的两面均分布有第一涂布区31、第二涂布区32和槽位区33，且第一涂布区31、第二涂布区32和槽位区33在第一段11的两面的分布位置分别相互对应。这样的结构使得在槽位区33背面对应的位置也是槽位区33，焊接极耳50时，可以减小极片的应力。
在一种可能实施的方式中，参考图3和图4所示，极耳50与集流体10两面的槽位区33中的一个槽位区33连接。可以是极耳50的连接段51与集流体一面的槽位区33通过激光焊接的方式焊接连接。
在一种可能实施的方式中，参考图2所示，第二涂布区32内的活性物质层20的厚度沿第一涂布区31的宽度方向呈逐渐递增、递减的梯度分布。
在一种可能实施的方式中，参考图10所示，第二涂布区32内的活性物质层20的厚度一致。
在一种可能实施的方式中，可以是第二涂布区32内的活性物质层20先均匀涂布，然后在第二涂布区32的厚度方向上按照梯度进行去除。
在一种可能实施的方式中，参考图7所示，第二涂布区32内的活性物质层20的表面呈波浪面状，即第二涂布区32内的活性物质层20可以呈波浪形的块状。
在一种可能实施的方式中，参考图6所示，第二涂布区32内的活性物质层20的表面呈倾斜状，即第二涂布区32内的活性物质层20可以呈三角形的块状。
在一种可能实施的方式中，参考图10所示，第二涂布区32内的活性物质层20的表面呈平面状，即第二涂布区32内的活性物质层20可以呈矩形块状。
在一种可能实施的方式中，集流体10两面的第二涂布区32内的活性物质层20的表面形状相同，也可以不同，即第一段11的两面分布的第二涂布区32内的活性物质层20的形状可以相同，也可以不同。例如，参考图5和图7所示，第一段11的两面分布的第二涂布区32内的活性物质层20可以都呈矩形块状或者都是表面为波浪形、或者都是表面为倾斜状。参考图8和图 9所示，也可以是第一段11的一面分布的第二涂布区32内的活性物质层20可以呈矩形块状，另一面分布的第二涂布区32内的活性物质层20可以呈表面为波浪形，或者另一面分布的第二涂布区32内的活性物质层20也可以呈表面为倾斜状。
可以根据电池的大小，调整极片的第二涂布区32的尺寸大小和槽位区33的尺寸大小。
本实施例中，焊接极耳50的槽位区33周围不需要进行切除处理，避免了对极片上极耳50的焊接位置的损伤，减少并优化槽位位置极片断带和极耳失效的问题。
在一种可能实施的方式中，集流体10还包括连接在第一段11至少一端的第二段12，第二段12的表面未附着活性物质层20。
在一种可能实施的方式中，上述极片可为正极片，也可以为负极片。
正极片和负极片中的集流体10的材料可以根据实际需要进行设置，在此不作进一步的限定。例如，正极片中的集流体10可以为铝箔，负电极片中的集流体10可以为铜箔。
正极片和负极片中的活性物质层20中活性物质的种类和比例也是可以根据实际需要进行设置的，在此不作进一步的限定。例如，负极片中的活性物质层20中的活性物质可以包括石墨、硬碳、硅、氧化亚硅等材料，正极片中活性物质层20中的活性物质可以包括钴酸锂、磷酸铁锂、锰酸锂等材料。
参考图5所示，本申请还提供一种极片料带，包括上述的极片，若干个极片沿集流体10的宽度方向依次连接，极片的第一段11与相邻的极片的第一段11相连接，且极片的第二段12与相邻的极片的第二段12相连接。
极片料带为加工极片的料材，为了提高生产效率，通常将极片料带的表面涂布好活性物质层20之后再进行极片分切，在极片分切步骤时，沿着极片料带上的分切线60进行分切，使得极片料带被分切成若干个极片。分切线60为沿着极片的长度方向延伸的虚拟线，分切完成之后，分切线60两侧的极片料带成为两个独立的极片。
在一种可能实施的方式中，极片的第二涂布区32的余留区322与相邻的极片的第二涂布区32的过渡区321相连接。这样的结构，参考图5和图7所示，使得在极片分切时，分切线60将第二涂布区32分切成为分别位于两个 不同极片上的余留区322和过渡区321，并且由于余留区322和过渡区321内的集流体10表面均涂布有活性物质层20，因而可以避免由于极片料带的分切误差导致在极片的第一段11上除了槽位区33之外的其他部分露出集流体10表面，避免影响电池的品质和电池的安全性能。
在一种可能实施的方式中，第一涂布区31附着的活性物质层20的厚度为20μm～200μm；和/或，第二涂布区32附着的活性物质层20的厚度为0μm～200μm。
例如，可以是第一涂布区31附着的活性物质层20的平均厚度为20μm，第二涂布区32附着的活性物质层20的平均厚度为10μm；也可以是第一涂布区31附着的活性物质层20的平均厚度为100μm，第二涂布区32附着的活性物质层20的平均厚度为50μm或80um；还可以是第一涂布区31附着的活性物质层20的平均厚度为200μm，第二涂布区32附着的活性物质层20的平均厚度为70μm或100um。满足第二涂布区32内的活性物质层20的厚度小于第一涂布区31内的活性物质层20的厚度。
在一种可能实施的方式中，极耳50的厚度为100μm～500μm。例如极耳50的平均厚度可以是100μm、200μm、300μm、400μm或500um。
本申请提供的一种极片料带，参考图5所示，由于过渡区321和余留区322内的集流体10表面均涂布有活性物质层20，即使受到分切误差的影响导致分切线60沿着集流体10的宽度的方向，向上或者向下偏移，最终的结果是导致过渡区321和与该过渡区321相接的余留区322的面积大小发生变化，不会导致余留区322内的集流体10露出，也不会导致在余留区322的位置出现缺口，从而确保了避免发生极片断带的问题。
极片料带的分切可以是通过制片机或者制片卷绕一体机实现，也可以是通过激光分切的方式加工出本实施例中的极片。
本申请还提供一种电池，包括壳体和容置在壳体内的电芯，电芯包括正极片、负极片和间隔在正极片和负极片之间的隔膜，正极片、负极片和隔膜层叠后卷绕在一起，正极片和负极片中的至少一者为上述的极片。
容易理解的是，本申请提供的一种电池，可以是正极片为上述的极片，负极片为常规的极片；也可以是负极片为上述的极片，正极片为常规的极片；当然，也可以是正极片或负极片都为上述的极片。
本申请提供的一种电池，由于采用了上述的极片，因而电芯表面具有较好的平整性，电池在循环充放电过程中极片表面所受应力均匀性较好，提高电池的使用寿命，有利于提升电池的充放电倍率。
隔膜将正极片和负极片隔开，防止正极片和负极片接触而短路，此外隔膜还具有能使电解液中的电解质离子通过的功能。
隔膜可以包括基材和涂覆层，其中基材可为聚乙烯(polythene，PE)单层膜、聚丙烯(polypropylene，PP)单层膜或聚丙烯-聚乙烯-聚丙烯三层复合膜，涂覆层可为多孔二氧化硅、三氧化二铝、二氧化钛和二氧化锆中的至少一种。
壳体内还填充有电解液，电芯浸在电解液中。
在一种可能实施的方式中，上述电芯可以为卷绕结构的电芯。
在一种可能实施的方式中，上述电池可以为软包电池、铝壳电池或圆柱电池。
在本申请的描述中，需要理解的是，所使用的术语“中心”、“长度”、“宽度”、“厚度”、“顶端”、“底端”、“上”、“下”、“左”、“右”、“前”、“后”、“竖直”、“水平”、“内”、“外”“轴向”、“周向”等指示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位置或原件必须具有特定的方位、以特定的构造和操作，因此不能理解为对本申请的限制。
此外，术语“第一”、“第二”仅用于描述目的，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量。由此，限定有“第一”、“第二”的特征可以明示或者隐含地包括一个或者更多个该特征。在本申请的描述中，“多个”的含义是至少两个，例如两个、三个等，除非另有明确具体的限定。
在本申请中，除非另有明确的规定和限定，术语“安装”、“相连”、“连接”、“固定”等应做广义理解，例如可以是固定连接，也可以是可拆卸连接，或成为一体；可以是机械连接，也可以是电连接或者可以互相通讯；可以是直接相连，也可以通过中间媒介间接相连，可以使两个元件内部的连通或两个元件的相互作用关系。对于本领域的普通技术人员而言，可以根据具体情况理解上述术语在本申请中的具体含义。
在本申请中，除非另有明确的规定和限定，第一特征在第二特征之“上”或之“下”可以包括第一和第二特征直接接触，也可以包括第一和第二特征不是直接接触而是通过它们之间的另外的特征接触。而且，第一特征在第二特征“之上”、“上方”和“上面”包括第一特征在第二特征正上方和斜上方，或仅仅表示第一特征水平高度高于第二特征。第一特征在第二特征“之下”、“下方”和“下面”包括第一特征在第二特征正下方和斜下方，或仅仅表示第一特征水平高度小于第二特征。
最后应说明的是：以上各实施例仅用以说明本申请的技术方案，而非对其限制；尽管参照前述各实施例对本申请进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分或者全部技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本申请各实施例技术方案的范围。

Claims (11)

  1. 一种极片，其特征在于，包括：集流体(10)和活性物质层(20)，所述集流体(10)包括第一段(11)，所述第一段(11)的至少一面分布有第一涂布区(31)、第二涂布区(32)和槽位区(33)；
    所述第二涂布区(32)包括过渡区(321)，在沿所述集流体(10)的宽度方向，所述过渡区(321)位于所述槽位区(33)和所述集流体(10)的边沿之间；
    所述活性物质层(20)附着于所述第一涂布区(31)和所述第二涂布区(32)内的所述集流体(10)表面；
    所述第二涂布区(32)内的所述活性物质层(20)的厚度小于所述第一涂布区(31)内的所述活性物质层(20)的厚度。
  2. 根据权利要求1所述的极片，其特征在于，所述第一涂布区(31)延伸到所述第一段(11)的长度方向和宽度方向的边缘，所述槽位区(33)和所述第二涂布区(32)均位于所述第一涂布区(31)的长度方向的中部。
  3. 根据权利要求1所述的极片，其特征在于，在沿所述集流体(10)的长度方向，所述槽位区(33)和所述过渡区(321)的长度的比值为S，其中，5≥S≥1。
  4. 根据权利要求1所述的极片，其特征在于，在沿所述集流体(10)的宽度方向上，所述过渡区(321)的宽度为2mm～5mm；和/或
    在沿所述集流体(10)的宽度方向上，所述槽位区(33)的宽度为9mm～30mm。
  5. 根据权利要求1所述的极片，其特征在于，所述第二涂布区(32)还包括余留区(322)，在沿所述集流体(10)的宽度方向上，所述余留区(322)与所述过渡区(321)的位置相对，且所述余留区(322)的宽度为0mm～5mm。
  6. 根据权利要求1所述的极片，其特征在于，所述第一段(11)的两面均分布有所述第一涂布区(31)、所述第二涂布区(32)和所述槽位区(33)，且所述第一涂布区(31)、所述第二涂布区(32)和所述槽位区(33)在所述第一段(11)的两面的分布位置分别相互对应。
  7. 根据权利要求6所述的极片，其特征在于，所述集流体(10)两面的 所述第二涂布区(32)内的所述活性物质层(20)的表面形状相同；或
    所述集流体(10)两面的所述第二涂布区(32)内的所述活性物质层(20)的表面形状不同。
  8. 根据权利要求1所述的极片，其特征在于，所述第二涂布区(32)内的所述活性物质层(20)的表面呈平面状、波浪面状、或倾斜状。
  9. 根据权利要求1-8任一所述的极片，其特征在于，还包括极耳(50)，所述极耳(50)包括相互连接的连接段(51)和伸出段(52)，所述连接段(51)与所述集流体(10)两面的所述槽位区(33)中的一个所述槽位区(33)连接固定连接，所述伸出段(52)沿所述集流体(10)的宽度方向，延伸到所述第一涂布区(31)的外侧。
  10. 根据权利要求9所述的极片，其特征在于，
    所述第一涂布区(31)附着的所述活性物质层(20)的厚度为20μm～200μm；和/或
    所述第二涂布区(32)附着的所述活性物质层(20)的厚度为0μm～200μm；和/或
    所述极耳(50)的厚度为100μm～500μm。
  11. 一种电池，包括壳体和容置在壳体内的电芯，其特征在于，所述电芯包括正极片、负极片和间隔在所述正极片和所述负极片之间的隔膜，所述正极片、所述负极片和所述隔膜层叠后卷绕在一起，所述正极片和所述负极片中的至少一者为权利要求1-9任一项所述的极片。
PCT/CN2022/130055 2021-11-04 2022-11-04 一种极片及电池 WO2023078428A1 (zh)

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