WO2023083045A1 - 电芯卷绕工艺、电芯卷绕装置、电芯、电池以及用电装置 - Google Patents

电芯卷绕工艺、电芯卷绕装置、电芯、电池以及用电装置 Download PDF

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Publication number
WO2023083045A1
WO2023083045A1 PCT/CN2022/128835 CN2022128835W WO2023083045A1 WO 2023083045 A1 WO2023083045 A1 WO 2023083045A1 CN 2022128835 W CN2022128835 W CN 2022128835W WO 2023083045 A1 WO2023083045 A1 WO 2023083045A1
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WIPO (PCT)
Prior art keywords
winding
battery
heating
cell
pole piece
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Ceased
Application number
PCT/CN2022/128835
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English (en)
French (fr)
Inventor
欧阳梅兰
张小文
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Contemporary Amperex Technology Co Ltd
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Contemporary Amperex Technology Co Ltd
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Application filed by Contemporary Amperex Technology Co Ltd filed Critical Contemporary Amperex Technology Co Ltd
Priority to EP22891841.3A priority Critical patent/EP4421941A4/en
Publication of WO2023083045A1 publication Critical patent/WO2023083045A1/zh
Priority to US18/661,562 priority patent/US20260081201A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/04—Construction or manufacture in general
    • H01M10/0404—Machines for assembling batteries
    • H01M10/0409—Machines for assembling batteries for cells with wound electrodes
    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L50/00—Electric propulsion with power supplied within the vehicle
    • B60L50/50—Electric propulsion with power supplied within the vehicle using propulsion power supplied by batteries or fuel cells
    • B60L50/60—Electric propulsion with power supplied within the vehicle using propulsion power supplied by batteries or fuel cells using power supplied by batteries
    • B60L50/66—Arrangements of batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2220/00—Batteries for particular applications
    • H01M2220/20—Batteries in motive systems, e.g. vehicle, ship, plane
    • 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 lithium-ion batteries, in particular to a battery winding process, a battery winding device, a battery, a battery and an electrical device.
  • lithium-ion batteries Due to the advantages of high energy density, high output power, long cycle life and low environmental pollution, lithium-ion batteries have been used more and more in the market.
  • Lithium-ion batteries include winding batteries, which are batteries composed of battery cells formed in a winding manner. Compared with the flat battery, the winding battery is made of high-voltage winding with a plate of only about 1mm. Through special technological means, the battery has a super high-rate discharge capacity, excellent high and low temperature performance, and stable high temperature. Output voltage and higher energy density and other characteristics.
  • the present application provides a battery winding process, including steps:
  • Heating the winding device is provided with a heating part, and the heating part heats the heating areas on the two surfaces of the diaphragm layer respectively attached to the cathode electrode piece and the anode electrode piece;
  • Winding a winding needle is set on the winding device, and the heated separator layer, cathode electrode sheet and anode electrode sheet are wound through the winding needle.
  • the diaphragm layer is located between the cathode pole piece and the anode pole piece, the diaphragm layer is heated respectively towards the heating areas on the two surfaces of the cathode pole piece and the anode pole piece, so that the The PCS (polycarbosilane) polymer is melted and then wound, so that the cathode electrode sheet and the anode electrode sheet can be closely bonded to the separator layer.
  • PCS polycarbosilane
  • the adhesion and fixation of the cathode electrode piece and the anode electrode piece can be realized through the structure of the diaphragm layer itself, without adding other bonding structures. Therefore, the structure of the battery cell can be simplified to the greatest extent, the thickness of the battery core after winding can be reduced, and the volume of the battery core can be reduced.
  • the heating area in the heating step, is located on the side of the separator layer parallel to the winding direction, and the width of the heating area ranges from 2 mm to 4 mm.
  • the heating width when the heating width is less than 2 mm, the bonding effect of the cathode electrode sheet, the anode electrode sheet and the separator layer is not good because the bonding width is too small, and the cathode electrode sheet and the anode electrode cannot be fixed. piece.
  • the heating width is greater than 4mm, it will affect the intercalation and extraction of lithium ions in the bonding area, thereby deteriorating the performance of the battery cell.
  • the heating area in the heating step, is located on the side of the membrane layer parallel to the winding direction, and the length of the heating area is at least three turns.
  • the cathode electrode piece and the anode electrode piece cannot be effectively bonded to the diaphragm layer, and the fixing effect cannot be achieved.
  • the heating temperature of the heating part is 90°C-130°C.
  • the heating temperature exceeds 130°C
  • the melting of the diaphragm layer will easily cause the original micropores on the diaphragm layer to be blocked, affecting the transfer of lithium ions during charging and discharging, thereby deteriorating the resistance and capacity of the battery and cycle performance.
  • the heating temperature is lower than 90° C.
  • the PCS polymer on the diaphragm layer cannot be melted, and the effect of bonding and fixing cannot be achieved.
  • Pre-pressing after the winding step is completed, the battery core is obtained, the winding needle is pulled out from the battery core, and pressure is applied to pre-press, so as to shape and restrain the battery pole piece.
  • the multi-layer pole pieces will retract due to stress release.
  • applying proper pressure to the wound cell for preloading can play the role of shaping and restraining and improve the performance of the cell.
  • the winding device includes a plurality of winding rollers for transporting the membrane layer, and all the winding rollers are arranged at intervals along the conveying direction of the membrane layer.
  • the transportation and transfer of the separator layer, the cathode electrode sheet and the anode electrode sheet can be realized by a plurality of winding rollers.
  • the heating part is provided on one of the plurality of winding rollers that is close to the winding needle.
  • the heating part on a winding roller close to the winding needle by setting the heating part on a winding roller close to the winding needle, the heating temperature on the diaphragm layer can be ensured, and the failure of bonding and fixing due to cooling can be avoided.
  • the present application provides a cell winding device for operating the cell winding process as described above.
  • the cell winding device includes a winding device for cell winding.
  • a heating part is provided to heat the heating areas on the two surfaces of the diaphragm layer respectively attached to the cathode electrode sheet and the anode electrode sheet.
  • the heating part is located at the edge of the membrane layer parallel to the winding direction, and the heating width ranges from 2 mm to 4 mm.
  • the heating part is located at the edge of the membrane layer parallel to the winding direction, and the heating length is at least three turns.
  • the heating temperature of the heating part ranges from 90°C to 130°C.
  • the winding device includes a plurality of winding rollers for transporting the membrane layer, and all the winding rollers are arranged at intervals along the conveying direction of the membrane layer.
  • the heating part is provided on a winding roller close to the winding needle among the plurality of winding rollers.
  • the present application provides an electric core, which is prepared by the above-mentioned electric core winding process.
  • the present application provides a battery, including a casing and the above-mentioned electric core, and the electric core is arranged in the casing.
  • the present application provides an electrical device, including an electrical main body and the above-mentioned battery.
  • the above-mentioned cell winding process, cell winding device, cell, battery, and electrical device heat the diaphragm layer through the heating part, so that the PCS polymer on the diaphragm layer is melted at high temperature, and the cathode sheet and the anode
  • the pole piece acts as a bond, so that the cathode pole piece and the anode pole piece are closely bonded and fixed, preventing the pole piece from shrinking due to stress release after winding, resulting in a gap.
  • the problem of lithium deposition on the surface of the anode caused by the excessively long lithium ion transmission path during charging and discharging can be prevented, and the safety performance of the battery can be further improved.
  • FIG. 1 is a schematic structural view of a vehicle according to an embodiment of the present application.
  • FIG. 2 is a schematic structural view of a battery according to an embodiment of the present application.
  • FIG. 3 is a schematic structural view of a cell according to an embodiment of the present application.
  • Fig. 4 is a schematic structural diagram of a cell in an embodiment of the present application.
  • Fig. 5 is a schematic structural view of the cell shown in Fig. 4 when it is wound;
  • FIG. 6 is a schematic structural diagram of a diaphragm layer in the cell shown in FIG. 4 .
  • multiple refers to more than two (including two), similarly, “multiple groups” refers to more than two groups (including two), and “multiple pieces” refers to More than two pieces (including two pieces).
  • lithium-ion batteries are widely used in electric vehicles and consumer electronics products due to their advantages such as high energy density, high output power, long cycle life and low environmental pollution. With the continuous expansion of lithium-ion battery application fields, its market demand is also constantly expanding.
  • the production process of lithium-ion batteries usually includes the following steps: the first step is to prepare electrode slurry, which is mainly to mix electrode active materials, binders, solvents, etc., and stir and disperse fully to form a slurry; the second step , coating, the slurry prepared in the first step is uniformly coated on the current collector (aluminum foil or copper foil, etc.) with a specified thickness, and the solvent is dried; the third step is die-cutting of the pole piece, and the The pole piece is punched into the specified size and shape; the fourth step is lamination, the cathode and anode pieces and the diaphragm are assembled together, and after the glue is pasted, the pole core is formed; the fifth step is to assemble the pouch battery, and the Put the pole core into the aluminum-plastic film that has been punched, and complete the top seal, side seal, etc.
  • the sixth step is to inject the specified amount of electrolytic The liquid is injected into the inside of the pouch cell; the seventh step, the battery is sealed, and the gas inside the cell is pumped out in a vacuum environment to complete the sealing.
  • the wound battery also has a winding step in the above stacking step, where the cathode and anode sheets are bonded to the separator and wound to form a wound battery, and then proceed to the next step of assembly.
  • the winding battery is made by high-voltage winding with a plate of only about 1 millimeter (mm), and is made by special technological means. Therefore, compared with flat-panel batteries, it has the following characteristics: 1. Super high-rate discharge capability; 2. Excellent high and low temperature performance; 3. Stable high output voltage; 4. Higher energy density; 5. Excellent 6. It can be charged quickly and has a longer service life. Therefore, winding batteries have been more and more widely used in the market.
  • PCS polymer on the diaphragm layer specifically, its composition includes PVDF, that is, polyvinylidene fluoride. This component will melt at a certain temperature, and after melting, it will make the separator layer have a bonding effect.
  • PVDF polyvinylidene fluoride
  • the applicant in order to reduce the volume of the wound battery and solve the problem of lithium separation caused by the gap between the cathode electrode and the anode electrode, the applicant has designed a battery winding process after in-depth research. , using the structure of the separator layer itself, and through special technological means, the volume of the wound battery is reduced, and the problem of short circuit caused by lithium deposition in the wound battery can be solved.
  • the battery cells disclosed in the embodiments of the present application can be used, but not limited to, in electric devices such as vehicles, ships or aircrafts.
  • the power supply system comprising the electric device disclosed in this application can be used, which is conducive to bonding and fixing the cathode pole piece and the anode pole piece, and avoids gaps between the cathode pole piece and the anode pole piece to cause Lithium is separated, preventing the lithium ion transmission path from being too long during charging and discharging, which leads to the problem of lithium separation on the anode surface, and further improving the safety performance of the battery.
  • the embodiment of the present application provides an electric device using a battery as a power source.
  • the electric device can be, but not limited to, a mobile phone, a tablet, a notebook computer, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft, and the like.
  • electric toys may include fixed or mobile electric toys, such as game consoles, electric car toys, electric boat toys, electric airplane toys, etc.
  • spacecraft may include airplanes, rockets, space shuttles, spaceships, etc.
  • a vehicle 1000 is taken as an example of an electrical device according to an embodiment of the present application.
  • FIG. 1 is a schematic structural diagram of a vehicle 1000 provided by some embodiments of the present application.
  • the vehicle 1000 can be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle.
  • the interior of the vehicle 1000 is provided with a battery 100 , and the battery 100 may be provided at the bottom, head or tail of the vehicle 1000 .
  • the battery 100 can be used for power supply of the vehicle 1000 , for example, the battery 100 can be used as an operating power source of the vehicle 1000 .
  • the vehicle 1000 may further include a controller 200 and a motor 300 , the controller 200 is used to control the battery 100 to supply power to the motor 300 , for example, for starting, navigating and running the vehicle 1000 .
  • the battery 100 can not only be used as an operating power source for the vehicle 1000 , but can also be used as a driving power source for the vehicle 1000 , replacing or partially replacing fuel oil or natural gas to provide driving power for the vehicle 1000 .
  • FIG. 2 is a schematic structural diagram of a battery provided by an embodiment of the present application.
  • the battery 100 includes a box body 10 and a battery cell 20 , and the battery cell 20 is accommodated in the box body 10 .
  • the box body 10 is used to provide an accommodation space for the electric core 20, and the box body 10 may adopt various structures.
  • the box body 10 may include a first part 11 and a second part 12, the first part 11 and the second part 12 cover each other, and the first part 11 and the second part 12 jointly define a space for accommodating the electric core 20. Accommodate space.
  • the second part 12 can be a hollow structure with one end open, the first part 11 can be a plate-shaped structure, and the first part 11 covers the opening side of the second part 12, so that the first part 11 and the second part 12 jointly define an accommodation space ;
  • the first part 11 and the second part 12 can also be hollow structures with one side opening, and the opening side of the first part 11 is covered by the opening side of the second part 12 .
  • the box body 10 formed by the first part 11 and the second part 12 can be in various shapes, such as a cylinder, a cuboid and the like.
  • the battery 100 there may be a plurality of battery cells 20 , and the multiple battery cells 20 may be connected in series, parallel or mixed.
  • the mixed connection means that the multiple battery cells 20 are both connected in series and in parallel.
  • the plurality of battery cells 20 can be directly connected in series, in parallel or mixed together, and then the whole body composed of the plurality of battery cells 20 is accommodated in the box body 10 .
  • the battery 100 can also be in the form of a plurality of battery cells 20 connected in series, parallel or mixed first to form a battery module, and then multiple battery modules are connected in series, parallel or mixed to form a whole, and accommodated in the box 10 .
  • the battery 100 may also include other structures, for example, the battery 100 may also include a current flow component for realizing electrical connection between multiple battery cells 20 .
  • FIG. 3 is a schematic structural diagram of a battery cell provided by an embodiment of the present application.
  • each cell 20 may be a secondary battery or a primary battery; it may also be a lithium-sulfur battery, a sodium-ion battery or a magnesium-ion battery, but not limited thereto.
  • the battery core 20 may be in the form of a cylinder, a flat body, a cuboid or other shapes.
  • the battery cell 20 refers to the smallest unit forming a battery, and the battery cell 20 includes an end cover 21, a casing 22, a battery cell assembly 23 and other functional components.
  • the end cap 21 refers to a component that covers the opening of the casing 22 to isolate the internal environment of the battery cell 20 from the external environment.
  • the shape of the end cap 21 can be adapted to the shape of the housing 22 to fit the housing 22 .
  • the end cap 21 can be made of a material (such as aluminum alloy) with a certain hardness and strength, so that the end cap 21 is not easy to deform when being squeezed and collided, so that the battery cell 20 can have a higher structure Strength, safety performance can also be improved.
  • Functional components such as electrode terminals 21 a may be provided on the end cap 21 .
  • the electrode terminal 21 a can be used for electrical connection with the cell assembly 23 for outputting or inputting electric energy of the cell 20 .
  • the end cap 21 may also be provided with a pressure relief mechanism for releasing the internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold value.
  • the material of the end cap 21 can also be various, for example, copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which is not particularly limited in this embodiment of the present application.
  • an insulator can be provided inside the end cover 21 , and the insulator can be used to isolate the electrical connection components in the housing 22 from the end cover 21 to reduce the risk of short circuit.
  • the insulating member may be plastic, rubber or the like.
  • the casing 22 is a component used to cooperate with the end cap 21 to form an internal environment of the battery cell 20 , wherein the formed internal environment can be used to accommodate the battery cell assembly 23 , electrolyte and other components.
  • the housing 22 and the end cap 21 can be independent components, and an opening can be provided on the housing 22 , and the internal environment of the battery cell 20 can be formed by making the end cap 21 cover the opening at the opening.
  • the end cover 21 and the housing 22 can also be integrated. Specifically, the end cover 21 and the housing 22 can form a common connection surface before other components are inserted into the housing. When the inside of the housing 22 needs to be encapsulated , then make the end cover 21 cover the housing 22.
  • the housing 22 can be in various shapes and sizes, such as cuboid, cylinder, hexagonal prism and so on. Specifically, the shape of the casing 22 can be determined according to the specific shape and size of the battery core assembly 23 .
  • the housing 22 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which is not particularly limited in this embodiment of the present application.
  • the cell assembly 23 is a component in the cell 20 where electrochemical reactions occur.
  • One or more cell assemblies 23 may be contained in the casing 22 .
  • the cell assembly 23 is mainly formed by winding or stacking cathode sheets and anode sheets, and a separator is usually provided between the cathode sheets and the anode sheets.
  • the parts of the cathode sheet and the anode sheet with active material form the main body of the cell assembly 23 , and the parts of the cathode sheet and the anode sheet without active material respectively form tabs 23 a.
  • the cathode tab and the anode tab can be located at one end of the main body together or at two ends of the main body respectively.
  • the cathode active material and the anode active material react with the electrolyte, and the tab 23a is connected to the electrode terminal 21a to form a current loop.
  • an embodiment of the present application provides a battery winding process, including steps:
  • the heating unit 271 is provided on the winding device 27, and the heating unit 271 heats the heating regions 241 on the two surfaces of the separator layer 24 respectively attached to the cathode electrode piece 25 and the anode electrode piece 26.
  • the diaphragm layer 24 is located between the cathode pole piece 25 and the anode pole piece 26, the diaphragm layer 24 is heated towards the heating regions 241 on the two surfaces of the cathode pole piece 25 and the anode pole piece 26 respectively, so that the PCS on it is polymerized The material is melted and then wound, so that the cathode electrode sheet 25 and the anode electrode sheet 26 can be tightly bonded to the separator layer 24 .
  • the heating part 271 can be configured as a heating sheet, which is attached to the membrane layer 24 by the winding device 27 , so as to heat the membrane layer 24 . It can be understood that the heating part 271 can also be configured as other heating structures, such as heating tubes, infrared heaters, etc., which will not be repeated here.
  • the heating area 241 in the heating step, is located on the side of the separator layer 24 parallel to the winding direction, and the width of the heating area 241 is in the range of 2mm-4mm.
  • the heating area 241 is at the edge of the diaphragm layer 24 and extends 2mm-4mm inwardly from the edge.
  • the heating area 241 generally includes two, respectively located on two sides of the membrane layer 24, and the width is 2mm-4mm. That is, heating both the left and right edges of the diaphragm layer 24 can make the cathode electrode piece 25 and the anode electrode piece 26 adhere to the diaphragm layer 24 more tightly.
  • the width of the heating region 241 is less than 2 mm, the bonding effect of the cathode electrode piece 25, the anode electrode piece 26 and the diaphragm layer 24 is not good due to the too small bonding width, and the cathode electrode piece cannot be fixed. 25 and the anode pole piece 26.
  • the width of the heating region 241 is greater than 4 mm, it will affect the intercalation and extraction of lithium ions in the bonding region, thereby deteriorating the performance of the battery cell.
  • the length of the heating region 241 is at least three turns. That is, the length of the heating area 241 on the diaphragm layer 24 should be such that the cathode electrode sheet 25 , the diaphragm layer 24 and the anode electrode sheet 26 are wound together for at least three turns. If the length of the heating region 241 is less than three turns, the cathode electrode piece 25 and the anode electrode piece 26 cannot be effectively bonded to the diaphragm layer, and the fixing effect cannot be achieved.
  • the heating temperature of the heating part 271 ranges from 90°C to 130°C.
  • the separator layer 24 is a fibrous structure, there are several fine through holes distributed thereon, and the through holes provide channels for the transfer of lithium ions.
  • the heating temperature exceeds 130° C.
  • the melting of the diaphragm layer 24 will easily cause the original micropores on it to be blocked, affecting the transfer of lithium ions during charging and discharging, thereby deteriorating the resistance, capacity and cycle performance of the battery.
  • the heating temperature is lower than 90° C., the PCS polymer on the diaphragm layer 24 cannot be melted, and the effect of bonding and fixing cannot be achieved.
  • Winding the winding device 27 is provided with a winding needle 272 , and the heated separator layer 24 , the cathode electrode piece 25 and the anode electrode piece 26 are wound through the winding needle 272 .
  • the multi-layer pole pieces will retract due to stress release.
  • applying proper pressure to the wound cell for preloading can play the role of shaping and restraining and improve the performance of the cell.
  • the winding device 27 in the above cell winding process includes a plurality of winding rollers 273 for transporting the separator layer, and all the winding rollers 273 are arranged at intervals along the conveying direction of the separator layer 24 .
  • the diaphragm layer 24 , the cathode electrode piece 25 and the anode electrode piece 26 respectively correspond to a plurality of winding rollers 273 .
  • the heating part 271 is disposed on a winding roller 273 close to the winding needle 272 among the plurality of winding rollers 273 . That is, the heating part 271 is disposed on a winding roller 273 closest to the winding needle 272 , so as to prevent the heated separator layer 24 from being unable to be fixed due to cooling during transportation.
  • the present application also provides a cell winding device for operating the above cell winding process, including a winding device 27 for cell winding.
  • a heating unit 271 is provided on the winding device 27 to heat the heating regions 241 on the two surfaces of the separator layer 24 respectively attached to the cathode electrode sheet 25 and the anode electrode sheet 26 .
  • the separator layer 24 is placed between the cathode pole piece 25 and the anode pole piece 26 to isolate the cathode pole piece 25 from the anode pole piece 26 . Further, the heating regions 241 on the two surfaces of the separator layer 24 respectively facing the cathode electrode piece 25 and the anode electrode piece 26 are heated to melt the PCS polymer on it. Accordingly, when winding, the separator layer 24 has adhesiveness toward both sides of the cathode tab 25 and the anode tab 26 . Thus, the cathode electrode sheet 25 and the anode electrode sheet 26 can be closely bonded to the separator layer 24 during the winding process.
  • the heating part 271 can be configured as a heating sheet, which is attached to the membrane layer 24 by the winding device 27 , so as to heat the membrane layer 24 . It can be understood that the heating part 271 can also be configured as other heating structures, such as heating tubes, infrared heaters, etc., which will not be repeated here.
  • the heating portion 271 is located at the edge of the membrane layer 24 parallel to the winding direction, and the heating width is 2mm-4mm.
  • the edge of the diaphragm layer 24 is heated by the heating part 271 , and the heating width is 2mm-4mm.
  • the heating part 271 heats both side edges of the separator layer 24 along the winding direction, and the heating width of both sides is 2mm-4mm. In this way, both sides of the diaphragm layer 24 can be ensured to have adhesive ability.
  • the heating length of the heating part 271 is at least three turns. That is, the heating length of the heating part 271 on the diaphragm layer 24 should be such that the cathode electrode sheet 25 , the diaphragm layer 24 and the anode electrode sheet 26 are wound together for at least three turns. If the heating length is less than three turns, the cathode electrode piece 25 and the anode electrode piece 26 cannot be effectively bonded to the diaphragm layer 24 , and the fixing effect cannot be achieved.
  • the heating temperature of the heating part 271 ranges from 90°C to 130°C.
  • the separator layer 24 is a fibrous structure, there are several fine through holes distributed thereon, and the through holes provide channels for the transfer of lithium ions.
  • the heating temperature exceeds 130° C.
  • the melting of the diaphragm layer 24 will easily cause the original micropores on it to be blocked, affecting the transfer of lithium ions during charging and discharging, thereby deteriorating the resistance, capacity and cycle performance of the battery.
  • the heating temperature is lower than 90 DEG C, the PCS polymer on the diaphragm layer 24 cannot be melted, and the effect of bonding and fixing cannot be achieved.
  • the winding device 27 includes a plurality of winding rollers 273 for transporting the membrane layer 24 , and all the winding rollers 273 are arranged at intervals along the conveying direction of the membrane layer 24 .
  • the separator layer 24 , the cathode electrode sheet 25 and the anode electrode sheet 26 respectively correspond to a plurality of winding rollers 273 . Since the separator layer 24 , the cathode electrode sheet 25 and the anode electrode sheet 26 have long lengths before winding, a plurality of winding rollers 273 are required to realize the transportation and transfer of the separator layer 24 , the cathode electrode sheet 25 and the anode electrode sheet 26 .
  • the heating part 271 is disposed on a winding roller 273 close to the winding needle 272 among the plurality of winding rollers 273 . That is, the heating part 271 is disposed on a winding roller 273 closest to the winding needle 272 , so as to prevent the heated separator layer 24 from being unable to be fixed due to cooling during transportation.
  • the present application also provides a battery, which can be prepared by the above-mentioned battery winding process.
  • the present application also provides a battery, including a casing and the above-mentioned battery cell, and the battery cell is arranged in the casing.
  • the present application also provides an electrical device, including an electrical main body and the above-mentioned battery.
  • a heating part 271 is provided on the winding roller 273 closest to the winding needle 272 . It is made to heat both sides of the edge of the diaphragm layer 24, and the heating width range is set to 2mm-4mm.
  • the diaphragm layer 24, the cathode pole piece 25 and the anode pole piece 26 are respectively fixed on the corresponding winding rollers 273, and the diaphragm layer 24, the cathode pole piece 25 and the anode pole piece 26 are guided by the winding roller 273 Transfer to rolling needles 272 respectively.
  • the separator layer 24 needs to be kept between the cathode electrode piece 25 and the anode electrode piece 26 .
  • the winding step can be started.
  • the heating temperature of the heating part 271 is controlled at 90° C. to 130° C., and the separator layer 24 is heated synchronously during the winding process.
  • the heated separator layer 24 is bonded to the cathode pole piece 25 and the anode pole piece 26 respectively during the winding process, so as to achieve a fixing effect.
  • the winding needle 272 is pulled out from the battery core, and a certain pressure is applied to pre-press the battery core. In this way, it can play the role of shaping and restraining the pole pieces of the battery, and prevent the gap between the pole pieces from becoming larger during the production process.
  • the cell winding process, cell winding device, cell, battery and electrical device in the above embodiments have at least the following advantages:
  • the structure of the diaphragm layer 24 is used to achieve bonding, there is no need to add other bonding structures, the structure of the cell can be simplified to the greatest extent, the thickness of the cell after winding can be reduced, the volume of the cell can be reduced, and the cell volume can be improved. performance;
  • Pre-pressing the wound battery core can avoid the retraction phenomenon between the multi-layer pole pieces due to stress release after the winding needle 272 is pulled out from the battery core, thus playing a role in the battery pole piece
  • the effect of shaping and binding improves the performance of the battery cell.

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Abstract

本申请涉及一种电芯卷绕工艺、电芯卷绕装置、电芯、电池以及用电装置，通过设置加热部(271)对隔膜层(24)加热，使隔膜层(24)上的PCS聚合物在高温下熔化，对阴极极片(25)及阳极极片(26)起到粘结作用，使得阴极极片(25)与阳极极片(26)紧密粘接固定，防止卷绕结束后极片由于应力释放出现回缩而产生间隙的情况。由此，可防止充放电时锂离子传输路径过长导致阳极表面析锂的问题，进一步地提高电池的安全性能。

Description

电芯卷绕工艺、电芯卷绕装置、电芯、电池以及用电装置
交叉引用
本申请引用于2021年11月11日递交的名称为“一种电芯卷绕工艺、电芯卷绕装置、电芯、电池以及用电装置”的第202111335028.7号中国专利申请，其通过引用被全部并入本申请。
技术领域
本申请涉及锂离子电池技术领域，特别是涉及一种电芯卷绕工艺、电芯卷绕装置、电芯、电池以及用电装置。
背景技术
锂离子电池由于具备能量密度大、输出功率高、循环寿命长以及环境污染小等优点，在市场中得到越来越多的应用。
锂离子电池包括卷绕电池，是以卷绕方式组合成形的电芯所组成的电池。相比于平板电池而言，卷绕电池采用仅有1mm左右的极板高压卷绕而成，通过特殊的工艺手段使得电池具有超强的高倍率放电能力、优秀的高低温性能、平稳的高输出电压以及更高的能量密度等特点。
然而，卷绕电池在高压卷绕时，阴极极片与阳极极片的弯折部易出现间隙引起析锂，此外，若弯折部掉料则会进一步恶化析锂情况，出现电池内部短路的安全隐患。
发明内容
基于此，有必要针对现有技术中卷绕电池阴极极片与阳极极片之间易出现间隙而导致析锂的问题，提供一种电芯卷绕工艺、电芯卷绕装置、电芯、电池以及用电装置。
第一方面，本申请提供了一种电芯卷绕工艺，包括步骤：
起卷，将隔膜层、阴极极片以及阳极极片的起始端固定于用于电芯卷绕的卷绕装置上，且隔膜层置于阴极极片及阳极极片之间；
加热，卷绕装置上设置加热部，加热部对隔膜层分别与阴极极片及阳极极片相贴合的两个表面上的加热区域进行加热；
卷绕，卷绕装置上设置卷针，将加热后的隔膜层与阴极极片以及阳极极片通过卷针进行卷绕。
本申请实施例的技术方案中，由于隔膜层位于阴极极片与阳极极片之间，将隔膜层分别朝向阴极极片及阳极极片的两个表面上的加热区域进行加热，使其上的PCS(聚碳硅烷) 聚合物熔化，然后进行卷绕，则可使阴极极片与阳极极片紧密粘接至隔膜层上。
由此，可以通过隔膜层自身结构实现阴极极片与阳极极片的粘接固定，且无需增加其他粘接结构。从而能够最大程度的简化电芯的结构，降低电芯卷绕后的厚度，减小电芯体积。
在一些实施例中，在加热步骤中，加热区域位于隔膜层平行于卷绕方向的侧边，加热区域的宽度范围为2mm-4mm。
本申请实施例的技术方案中，当加热宽度小于2mm时，由于粘接的宽度过小，导致阴极极片、阳极极片与隔膜层的粘接效果不好，无法固定阴极极片与阳极极片。而当加热宽度大于4mm时，将会影响粘接区域锂离子的嵌入和脱出，从而恶化电芯性能。
在一些实施例中，在加热步骤中，加热区域位于隔膜层平行于卷绕方向的侧边，加热区域的长度为至少三圈。
本申请实施例的技术方案中，若加热长度少于三圈，则无法有效地将阴极极片与阳极极片粘接至隔膜层，起不到固定作用。
在一些实施例中，在加热步骤中，加热部的加热温度为90℃-130℃。
本申请实施例的技术方案中，当加热温度超过130℃时，隔膜层熔化易导致隔膜层上原有的微孔被封堵，影响充放电过程中锂离子的转移，从而恶化电池的电阻、容量以及循环等性能。而当加热温度低于90℃时，无法熔化隔膜层上的PCS聚合物，起不到粘接固定的作用。
在一些实施例中，在卷绕步骤之后，还包括步骤：
预压，卷绕步骤完成后得到电芯，将卷针从电芯上拔出，并施以压力进行预压，以对电芯极片进行整形束缚。
本申请实施例的技术方案中，由于卷绕完成将卷针从电芯中拔出后，多层极片之间由于应力释放将出现回缩的情况。为了避免上述情况，向卷绕完成的电芯施加适当的压力进行预压，能够起到整形束缚的作用，提高电芯的性能。
在一些实施例中，卷绕装置包括用于运输隔膜层的多个卷绕辊，全部卷绕辊沿隔膜层的运输方向间隔设置。
本申请实施例的技术方案中，通过多个卷绕辊能够实现隔膜层、阴极极片以及阳极极片的运输转移。
在一些实施例中，在加热步骤中，加热部设于多个卷绕辊中靠近卷针的一个卷绕辊上。
本申请实施例的技术方案中，通过将加热部设于靠近卷针的一个卷绕辊上，能够确保隔膜层上的加热温度，避免因冷却而导致无法粘接固定。
第二方面，本申请提供了一种电芯卷绕装置，用于操作如上所述的电芯卷绕工艺，电芯卷绕装置包括用于电芯卷绕的卷绕装置，卷绕装置上设置加热部，以对隔膜层分别与阴极极片及阳极极片相贴合的两个表面上的加热区域进行加热。
在一些实施例中，加热部位于隔膜层平行于卷绕方向的边缘处，且加热宽度范围为2mm-4mm。
在一些实施例中，加热部位于隔膜层平行于卷绕方向的边缘处，且加热长度为至少三圈。
在一些实施例中，加热部的加热温度为范围90℃-130℃。
在一些实施例中，卷绕装置包括用于运输隔膜层的多个卷绕辊，全部卷绕辊沿隔膜层的运输方向间隔设置。
在一些实施例中，加热部设于多个卷绕辊中靠近卷针的一个卷绕辊上。
第三方面，本申请提供了一种电芯，通过如上所述的电芯卷绕工艺制备而成。
第四方面，本申请提供了一种电池，包括壳体及如上所述的电芯，电芯设置于壳体内。
第五方面，本申请提供了一种用电装置，包括用电主体及如上所述的电池。
上述的电芯卷绕工艺、电芯卷绕装置、电芯、电池以及用电装置，通过加热部对隔膜层加热，使隔膜层上的PCS聚合物在高温下熔化，对阴极极片及阳极极片起到粘结作用，使得阴极极片与阳极极片紧密粘接固定，防止卷绕结束后极片由于应力释放出现回缩而产生间隙的情况。由此，可防止充放电时锂离子传输路径过长导致阳极表面析锂的问题，进一步地提高电池的安全性能。
上述说明仅是本申请技术方案的概述，为了能够更清楚了解本申请的技术手段，而可依照说明书的内容予以实施，并且为了让本申请的上述和其它目的、特征和优点能够更明显易懂，以下特举本申请的具体实施方式。
附图说明
通过阅读对下文实施方式的详细描述，各种其他的优点和益处对于本领域普通技术人员将变得清楚明了。附图仅用于示出实施方式的目的，而并不认为是对本申请的限制。而且在全部附图中，用相同的附图标号表示相同的部件。在附图中：
图1为本申请一实施例的车辆的结构示意图；
图2为本申请一实施例的电池的结构示意图；
图3为本申请一实施例的电芯的结构示意图；
图4为本申请一实施例中电芯的结构示意图；
图5为图4所示电芯进行卷绕时的结构示意图；
图6为图4所示电芯中隔膜层的结构示意图。
1000、车辆；100、电池；200、控制器；300、马达；10、箱体；20、电芯；11、第一部分；12、第二部分；21、端盖；22、壳体；23、电芯组件；24、隔膜层；25、阴极极片；26、阳极极片；27、卷绕装置；21a、电极端子；23a、极耳；241、加热区域；271、加热部； 272、卷针；273、卷绕辊。
具体实施方式
下面将结合附图对本申请技术方案的实施例进行详细的描述。以下实施例仅用于更加清楚地说明本申请的技术方案，因此只作为示例，而不能以此来限制本申请的保护范围。
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，不是旨在于限制本申请；本申请的说明书和权利要求书及上述附图说明中的术语“包括”和“具有”以及它们的任何变形，意图在于覆盖不排他的包含。
在本申请实施例的描述中，技术术语“第一”“第二”等仅用于区别不同对象，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、特定顺序或主次关系。在本申请实施例的描述中，“多个”的含义是两个以上，除非另有明确具体的限定。
在本文中提及“实施例”意味着，结合实施例描述的特定特征、结构或特性可以包含在本申请的至少一个实施例中。在说明书中的各个位置出现该短语并不一定均是指相同的实施例，也不是与其它实施例互斥的独立的或备选的实施例。本领域技术人员显式地和隐式地理解的是，本文所描述的实施例可以与其它实施例相结合。
在本申请实施例的描述中，术语“和/或”仅仅是一种描述关联对象的关联关系，表示可以存在三种关系，例如A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B这三种情况。另外，本文中字符“/”，一般表示前后关联对象是一种“或”的关系。
在本申请实施例的描述中，术语“多个”指的是两个以上(包括两个)，同理，“多组”指的是两组以上(包括两组)，“多片”指的是两片以上(包括两片)。
在本申请实施例的描述中，技术术语“中心”“纵向”“横向”“长度”“宽度”“厚度”“上”“下”“前”“后”“左”“右”“竖直”“水平”“顶”“底”“内”“外”“顺时针”“逆时针”“轴向”“径向”“周向”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实施例和简化描述，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实施例的限制。
在本申请实施例的描述中，除非另有明确的规定和限定，技术术语“安装”“相连”“连接”“固定”等术语应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或成一体；也可以是机械连接，也可以是电连接；可以是直接相连，也可以通过中间媒介间接相连，可以是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实施例中的具体含义。
目前，从市场形势的发展来看，锂离子电池由于具备能量密度大、输出功率高、循环寿命长和环境污染小等优点而被广泛应用于电动汽车以及消费类电子产品中。随着锂离子电 池应用领域的不断扩大，其市场的需求量也在不断地扩增。
锂离子电池的生产工艺流程通常包含如下步骤：第一步，电极浆料制备，主要是将电极活性材料、粘结剂、溶剂等混合在一起，充分搅拌分散后，形成浆料；第二步，涂布，将第一步制备的浆料以指定厚度均匀涂布到集流体(铝箔或铜箔等)上，并烘干溶剂；第三步，极片冲切，将上一步制作出来的极片冲切成指定的尺寸形状；第四步，叠片，将阴阳极片、隔膜装配到一起，完成贴胶后，形成极芯；第五步，组装软包电池，将上一步生产的极芯装入已经冲好坑的铝塑膜，并完成顶封、侧封等(预留注液口)，形成未注液的软包电池；第六步，注液，将指定量的电解液注入软包电芯内部；第七步，电池密封，在真空环境中将电芯内部的气体抽出并完成密封。
进一步地，由于锂离子电池分为卷绕电池与平板电池。其中，卷绕电池在上述叠片步骤中，还具有卷绕步骤，将阴阳极片与隔膜贴合并进行卷绕，形成卷绕电池，然后再进行下一步组装。
卷绕电池由于采用仅有1毫米(mm)左右的极板高压卷绕而成，且采用特殊的工艺手段制成。因此与平板电池相比，其具有以下特点：1、超强的高倍率放电能力；2、优秀的高低温性能；3、平稳的高输出电压；4、更高的能量密度；5、具有优异的抗震性能；6、可快速充电，且使用寿命更长。因此，卷绕电池在市场上得到了越来越广泛的应用。
随着卷绕电池的广泛使用，人们对卷绕电池的性能要求也越来越高。为了使用更加方便，人们要求卷绕电池具有更高的能量密度及更小的体积。基于此，当卷绕电池完成卷绕时，进行压合时的压力会更大。
然而申请人发现，随着压合时的压力不断增大，卷绕电池弯折部的弯折角度越来越小。由此，导致阴极极片与阳极极片弯折部的弯折角度越来越小，从而大大增加了阴极极片与阳极极片在弯折部位置的涂料脱落的概率，从而增加了电池析锂的风险。
进一步地，申请人注意到，隔膜层上具有一种PCS聚合物，具体地，其成分包括PVDF，即聚偏氟乙烯。这种成分在一定温度下会熔化，熔化之后使得隔膜层具有粘结作用。在此基础上，申请人想到，若使隔膜层上的PCS聚合物在特定条件下熔化，则可以通过其自身使阴极极片与阳极极片相互粘接固定，既解决了阴极极片与阳极极片的粘接问题，又无需增加外部结构，简化了卷绕电池的结构，进而使得卷绕电池经压合后能够具有更小的体积。
基于以上考虑，为了在减小卷绕电池体积的基础上，解决阴极极片与阳极极片弯折部产生间隙而析锂的问题，申请人经过深入研究，设计了一种电芯卷绕工艺，利用隔膜层自身结构，经过特殊的工艺手段，减小卷绕电池的体积，且能够解决卷绕电池析锂短路的问题。
本申请实施例公开的电芯可以但不限用于车辆、船舶或飞行器等用电装置中。可以使用具备本申请公开的电芯、电池等组成该用电装置的电源系统，这样，有利于粘接固定阴极极片与阳极极片，避免阴极极片与阳极极片之间出现间隙而导致析锂，防止充放电时锂离 子传输路径过长导致阳极表面析锂的问题，进一步地提高电池的安全性能。
本申请实施例提供一种使用电池作为电源的用电装置，用电装置可以为但不限于手机、平板、笔记本电脑、电动玩具、电动工具、电瓶车、电动汽车、轮船、航天器等等。其中，电动玩具可以包括固定式或移动式的电动玩具，例如，游戏机、电动汽车玩具、电动轮船玩具和电动飞机玩具等等，航天器可以包括飞机、火箭、航天飞机和宇宙飞船等等。
以下实施例为了方便说明，以本申请一实施例的一种用电装置以车辆1000为例进行说明。
请参照图1，图1为本申请一些实施例提供的车辆1000的结构示意图。车辆1000可以为燃油汽车、燃气汽车或新能源汽车，新能源汽车可以是纯电动汽车、混合动力汽车或增程式汽车等。车辆1000的内部设置有电池100，电池100可以设置在车辆1000的底部或头部或尾部。电池100可以用于车辆1000的供电，例如，电池100可以作为车辆1000的操作电源。车辆1000还可以包括控制器200和马达300，控制器200用来控制电池100为马达300供电，例如，用于车辆1000的启动、导航和行驶时的工作用电需求。
在本申请一些实施例中，电池100不仅可以作为车辆1000的操作电源，还可以作为车辆1000的驱动电源，代替或部分地代替燃油或天然气为车辆1000提供驱动动力。
请参看图2，图2为本申请一实施例提供的电池的结构示意图。电池100包括箱体10和电芯20，电芯20容纳于箱体10内。其中，箱体10用于为电芯20提供容纳空间，箱体10可以采用多种结构。在一些实施例中，箱体10可以包括第一部分11和第二部分12，第一部分11与第二部分12相互盖合，第一部分11和第二部分12共同限定出用于容纳电芯20的容纳空间。第二部分12可以为一端开口的空心结构，第一部分11可以为板状结构，第一部分11盖合于第二部分12的开口侧，以使第一部分11与第二部分12共同限定出容纳空间；第一部分11和第二部分12也可以是均为一侧开口的空心结构，第一部分11的开口侧盖合于第二部分12的开口侧。当然，第一部分11和第二部分12形成的箱体10可以是多种形状，比如，圆柱体、长方体等。
在电池100中，电芯20可以是多个，多个电芯20之间可串联或并联或混联，混联是指多个电芯20中既有串联又有并联。多个电芯20之间可直接串联或并联或混联在一起，再将多个电芯20构成的整体容纳于箱体10内。当然，电池100也可以是多个电芯20先串联或并联或混联组成电池模块形式，多个电池模块再串联或并联或混联形成一个整体，并容纳于箱体10内。电池100还可以包括其他结构，例如，该电池100还可以包括汇流部件，用于实现多个电芯20之间的电连接。
请参看图3，图3为本申请一实施例提供的电芯的结构示意图。其中，每个电芯20可以为二次电池或一次电池；还可以是锂硫电池、钠离子电池或镁离子电池，但不局限于此。电芯20可呈圆柱体、扁平体、长方体或其它形状等。具体地，电芯20是指组成电池的最小 单元，电芯20包括有端盖21、壳体22、电芯组件23以及其他的功能性部件。
端盖21是指盖合于壳体22的开口处以将电芯20的内部环境隔绝于外部环境的部件。不限地，端盖21的形状可以与壳体22的形状相适应以配合壳体22。可选地，端盖21可以由具有一定硬度和强度的材质(如铝合金)制成，这样，端盖21在受挤压碰撞时就不易发生形变，使电芯20能够具备更高的结构强度，安全性能也可以有所提高。端盖21上可以设置有如电极端子21a等的功能性部件。电极端子21a可以用于与电芯组件23电连接，以用于输出或输入电芯20的电能。在一些实施例中，端盖21上还可以设置有用于在电芯20的内部压力或温度达到阈值时泄放内部压力的泄压机构。端盖21的材质也可以是多种的，比如，铜、铁、铝、不锈钢、铝合金、塑胶等，本申请实施例对此不作特殊限制。在一些实施例中，在端盖21的内侧还可以设置有绝缘件，绝缘件可以用于隔离壳体22内的电连接部件与端盖21，以降低短路的风险。示例性的，绝缘件可以是塑料、橡胶等。
壳体22是用于配合端盖21以形成电芯20的内部环境的组件，其中，形成的内部环境可以用于容纳电芯组件23、电解液以及其他部件。壳体22和端盖21可以是独立的部件，可以于壳体22上设置开口，通过在开口处使端盖21盖合开口以形成电芯20的内部环境。不限地，也可以使端盖21和壳体22一体化，具体地，端盖21和壳体22可以在其他部件入壳前先形成一个共同的连接面，当需要封装壳体22的内部时，再使端盖21盖合壳体22。壳体22可以是多种形状和多种尺寸的，例如长方体形、圆柱体形、六棱柱形等。具体地，壳体22的形状可以根据电芯组件23的具体形状和尺寸大小来确定。壳体22的材质可以是多种，比如，铜、铁、铝、不锈钢、铝合金、塑胶等，本申请实施例对此不作特殊限制。
电芯组件23是电芯20中发生电化学反应的部件。壳体22内可以包含一个或更多个电芯组件23。电芯组件23主要由阴极片和阳极片卷绕或层叠放置形成，并且通常在阴极片和阳极片之间设有隔膜。阴极片和阳极片具有活性物质的部分构成电芯组件23的主体部，阴极片和阳极片不具有活性物质的部分各自构成极耳23a。阴极极耳和阳极极耳可以共同位于主体部的一端或是分别位于主体部的两端。在电池的充放电过程中，阴极活性物质和阳极活性物质与电解液发生反应，极耳23a连接电极端子21a以形成电流回路。
请参阅图4、图5以及图6所示，本申请一实施例提供了一种电芯卷绕工艺，包括步骤：
S10：起卷，将隔膜层24、阴极极片25以及阳极极片26的起始端固定于用于电芯卷绕的卷绕装置27上，且隔膜层24置于阴极极片25及阳极极片26之间。
S20：加热，卷绕装置27上设置加热部271，加热部271对隔膜层24分别与阴极极片25及阳极极片26相贴合的两个表面上的加热区域241进行加热。
由于隔膜层24位于阴极极片25与阳极极片26之间，将隔膜层24分别朝向阴极极片25及阳极极片26的两个表面上的加热区域241进行加热，使其上的PCS聚合物熔化，然后 进行卷绕，则可使阴极极片25与阳极极片26紧密粘接至隔膜层24上。
需要说明的是，加热部271可设置为一加热片，通过卷绕装置27贴合至隔膜层24上，从而对隔膜层24进行加热。可以理解地，加热部271也可以设置为其他加热结构，例如加热管、红外线加热器等等，在此不作赘述。
在一些实施例中，在加热步骤中，加热区域241位于隔膜层24平行于卷绕方向的侧边，加热区域241的宽度范围为2mm-4mm。
具体地，加热区域241为隔膜层24的边缘处，且由边缘处向内延伸2mm-4mm。此外，加热区域241通常包括两个，分别位于隔膜层24的两个侧边，且宽度均为2mm-4mm。即对隔膜层24的左右两个边缘均进行加热，能够使得阴极极片25与阳极极片26与隔膜层24的贴合更加紧密。
此外，经过实验验证，当加热区域241的宽度小于2mm时，由于粘接的宽度过小，导致阴极极片25、阳极极片26与隔膜层24的粘接效果不好，无法固定阴极极片25与阳极极片26。而当加热区域241的宽度大于4mm时，将会影响粘接区域锂离子的嵌入和脱出，从而恶化电芯性能。
在一些实施例中，在加热步骤中，加热区域241的长度为至少三圈。即隔膜层24上加热区域241的长度应可使阴极极片25、隔膜层24以及阳极极片26共同卷绕至少三圈。若加热区域241的长度少于三圈，则无法有效地将阴极极片25与阳极极片26粘接至隔膜层，起不到固定作用。
此外，在加热步骤中，加热部271的加热温度范围为90℃-130℃。具体地，由于隔膜层24为纤维状结构，其上分布有若干细小通孔，该通孔为锂离子的转移提供通道。当加热温度超过130℃时，隔膜层24熔化易导致其上原有的微孔被封堵，影响充放电过程中锂离子的转移，从而恶化电池的电阻、容量以及循环等性能。而当加热温度低于90℃时，无法熔化隔膜层24上的PCS聚合物，起不到粘接固定的作用。
S30：卷绕，卷绕装置27上设置卷针272，将加热后的隔膜层24与阴极极片25以及阳极极片26通过卷针272进行卷绕。
S40：预压，卷绕步骤完成后得到电芯，将卷针272从电芯上拔出，并施以压力进行预压，以对电芯极片进行整形束缚。
具体地，当卷绕完成后，将卷针272从电芯中拔出后，多层极片之间由于应力释放将出现回缩的情况。为了避免上述情况，向卷绕完成的电芯施加适当的压力进行预压，能够起到整形束缚的作用，提高电芯的性能。
在一些实施例中，上述电芯卷绕工艺中的卷绕装置27包括用于运输隔膜层的多个卷绕辊273，全部卷绕辊273沿隔膜层24的运输方向间隔设置。具体到本实施例中，隔膜层24、阴极极片25以及阳极极片26分别对应多个卷绕辊273。由于隔膜层24、阴极极片25以及阳 极极片26在卷绕前的长度较长，需要通过多个卷绕辊273实现隔膜层24、阴极极片25以及阳极极片26的运输转移。
在一些实施例中，加热部271设于多个卷绕辊273中靠近卷针272的一个卷绕辊273上。即加热部271设于最接近卷针272的一个卷绕辊273上，从而能够避免加热之后的隔膜层24在运输过程中冷却而导致无法固定。
基于与上述电芯卷绕工艺相同的构思，本申请还提供一种用于操作上述电芯卷绕工艺的电芯卷绕装置，包括用于电芯卷绕的卷绕装置27。其中，卷绕装置27上设置加热部271，以对隔膜层24分别与阴极极片25及阳极极片26相贴合的两个表面上的加热区域241进行加热。
具体地，进行电芯卷绕时，将隔膜层24放置于阴极极片25与阳极极片26之间，以隔离阴极极片25与阳极极片26。进一步地，对隔膜层24分别朝向阴极极片25及阳极极片26的两个表面上的加热区域241进行加热，使其上的PCS聚合物熔化。由此，在进行卷绕时，隔膜层24朝向阴极极片25与阳极极片26的两个侧面均具有粘结性。由此，阴极极片25与阳极极片26在卷绕过程中即可紧密粘接至隔膜层24上。
需要说明的是，加热部271可设置为一加热片，通过卷绕装置27贴合至隔膜层24上，从而对隔膜层24进行加热。可以理解地，加热部271也可以设置为其他加热结构，例如加热管、红外线加热器等等，在此不作赘述。
在一些实施例中，加热部271位于隔膜层24平行于卷绕方向的边缘处，且加热宽度为2mm-4mm。
具体地，通过加热部271对隔膜层24的边缘进行加热，且加热宽度为2mm-4mm。进行卷绕时，阴极极片25与阳极极片26的边缘处均能够紧密粘接于隔膜层24上，从而能够实现固定连接。并且，加热部271对隔膜层24沿卷绕方向的两个侧边边缘均进行加热，两边的加热宽度均为2mm-4mm。由此，可确保隔膜层24两边均具有粘接能力。
此外，经过实验验证，当加热宽度小于2mm时，由于粘接的宽度过小，导致阴极极片25、阳极极片26与隔膜层24的粘接效果不好，无法固定阴极极片25与阳极极片26。而当加热宽度大于4mm时，将会影响粘接区域锂离子的嵌入和脱出，从而恶化电芯性能。
在一些实施例中，加热部271的加热长度为至少三圈。即加热部271在隔膜层24上的加热长度应可使阴极极片25、隔膜层24以及阳极极片26共同卷绕至少三圈。若加热长度少于三圈，则无法有效地将阴极极片25与阳极极片26粘接至隔膜层24，起不到固定作用。
在一些实施例中，加热部271的加热温度范围为90℃-130℃。具体地，由于隔膜层24为纤维状结构，其上分布有若干细小通孔，该通孔为锂离子的转移提供通道。当加热温度超过130℃时，隔膜层24熔化易导致其上原有的微孔被封堵，影响充放电过程中锂离子的转移，从而恶化电池的电阻、容量以及循环等性能。而当加热温度低于90℃时，无法熔化隔膜 层24上的PCS聚合物，起不到粘接固定的作用。
在一些实施例中，卷绕装置27包括用于运输隔膜层24的多个卷绕辊273，全部卷绕辊273沿隔膜层24的运输方向间隔设置。
具体地，隔膜层24、阴极极片25以及阳极极片26分别对应多个卷绕辊273。由于隔膜层24、阴极极片25以及阳极极片26在卷绕前的长度较长，需要通过多个卷绕辊273实现隔膜层24、阴极极片25以及阳极极片26的运输转移。
在一些实施例中，加热部271设于多个卷绕辊273中靠近卷针272的一个卷绕辊273上。即加热部271设于最接近卷针272的一个卷绕辊273上，从而能够避免加热之后的隔膜层24在运输过程中冷却而导致无法固定。
基于与上述电芯卷绕装置相同的构思，本申请还提供一种电芯，可通过如上所述的电芯卷绕工艺制备而成。
基于与上述电芯相同的构思，本申请还提供一种电池，包括壳体及如上所述的电芯，电芯设置于壳体内。
基于与上述电池相同的构思，本申请还提供一种用电装置，包括用电主体及如上所述的电池。
本申请具体使用时，首先在与隔膜层24对应的多个卷绕辊273中，在距离卷针272最近的一个卷绕辊273上设置加热部271。使其对隔膜层24的边缘两侧进行加热，且将加热宽度范围设置为2mm-4mm。
其次，将隔膜层24、阴极极片25以及阳极极片26分别固定至各自对应的卷绕辊273上，并通过卷绕辊273的引导将隔膜层24、阴极极片25以及阳极极片26分别转移至卷针272上。在此过程中，需保持隔膜层24位于阴极极片25与阳极极片26之间。
将隔膜层24、阴极极片25以及阳极极片26固定好之后，可开始起卷步骤。同时，将加热部271的加热温度控制在90℃-130℃，在卷绕的过程中，同步对隔膜层24进行加热。加热后的隔膜层24在卷绕过程中与阴极极片25以及阳极极片26分别粘接，从而达到固定作用。
电芯卷绕完成后,将卷针272从电芯上拔出，并施加一定的压力，对电芯进行预压。由此，能够起到对电芯极片进行整形束缚的作用，防止生产过程中极片之间的间隙变大。
上述实施例中的电芯卷绕工艺、电芯卷绕装置、电芯、电池以及用电装置，至少具有以下优点：
1、对隔膜层24加热，使其上的PCS聚合物熔化而具有粘接功能，从而固定阴极极片25与阳极极片26，通过隔膜层24自身结构实现极片的粘接固定，操作过程简单，工作效率高；
2、由于利用隔膜层24自身结构实现粘接，无需增加其他粘接结构，能够最大程度的 简化电芯的结构，降低电芯卷绕后的厚度，进而能够减小电芯体积，提升电芯性能；
3、对卷绕完成的电芯进行预压，能够避免卷针272从电芯中拔出后，多层极片之间由于应力释放而出现的回缩现象，从而对电芯极片起到整形束缚的作用，提高电芯性能。
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，其均应涵盖在本申请的权利要求和说明书的范围当中。尤其是，只要不存在结构冲突，各个实施例中所提到的各项技术特征均可以任意方式组合起来。本申请并不局限于文中公开的特定实施例，而是包括落入权利要求的范围内的所有技术方案。

Claims (16)

  1. 一种电芯卷绕工艺，包括步骤：
    起卷，将隔膜层、阴极极片以及阳极极片的起始端固定于用于电芯卷绕的卷绕装置上，且所述隔膜层置于所述阴极极片及所述阳极极片之间；
    加热，所述卷绕装置上设置加热部，所述加热部对所述隔膜层分别与所述阴极极片及所述阳极极片相贴合的两个表面上的加热区域进行加热；
    卷绕，所述卷绕装置上设置卷针，将加热后的所述隔膜层与所述阴极极片以及所述阳极极片通过所述卷针进行卷绕。
  2. 根据权利要求1所述的电芯卷绕工艺，其中，在所述加热步骤中，所述加热区域位于所述隔膜层平行于卷绕方向的侧边，所述加热区域的宽度范围为2mm-4mm。
  3. 根据权利要求1或2所述的电芯卷绕工艺，其中，在所述加热步骤中，所述加热区域位于所述隔膜层平行于卷绕方向的侧边，所述加热区域的长度为至少三圈。
  4. 根据权利要求1-3任一项所述的电芯卷绕工艺，其中，在所述加热步骤中，所述加热部的加热温度范围为90℃-130℃。
  5. 根据权利要求1-4任一项所述的电芯卷绕工艺，其中，在所述卷绕步骤之后，还包括步骤：
    预压，所述卷绕步骤完成后得到电芯，将所述卷针从所述电芯上拔出，并施以压力进行预压，以对所述电芯极片进行整形束缚。
  6. 根据权利要求1-5任一项所述的电芯卷绕工艺，其中，所述卷绕装置包括用于传输所述隔膜层的多个卷绕辊，全部所述卷绕辊沿所述隔膜层的运输方向间隔设置。
  7. 根据权利要求6所述的电芯卷绕工艺，其中，在所述加热步骤中，所述加热部设于多个所述卷绕辊中靠近所述卷针的一个所述卷绕辊上。
  8. 一种电芯卷绕装置，用于操作如权利要求1-7任一项所述的电芯卷绕工艺，所述电芯卷绕装置包括用于电芯卷绕的卷绕装置，所述卷绕装置上设置加热部，以对所述隔膜层分别与所述阴极极片及所述阳极极片相贴合的两个表面上的加热区域进行加热。
  9. 根据权利要求8所述的电芯卷绕装置，其中，所述加热部位于所述隔膜层平行于卷绕方向的边缘处，且加热宽度范围为2mm-4mm。
  10. 根据权利要求8或9所述的电芯卷绕装置，其中，所述加热部位于所述隔膜层平行于卷绕方向的边缘处，且加热长度为至少三圈。
  11. 根据权利要求8-10任一项所述的电芯卷绕装置，其中，所述加热部的加热温度范围为90℃-130℃。
  12. 根据权利要求8-11任一项所述的电芯卷绕装置，其中，所述卷绕装置包括用于运输 所述隔膜层的多个卷绕辊，全部所述卷绕辊沿所述隔膜层的运输方向间隔设置。
  13. 根据权利要求12所述的电芯卷绕装置，其中，所述加热部设于多个所述卷绕辊中靠近所述卷针的一个所述卷绕辊上。
  14. 一种电芯，通过如权利要求1-7任一项所述的电芯卷绕工艺制备而成。
  15. 一种电池，包括壳体及如权利要求14所述的电芯，所述电芯设置于所述壳体内。
  16. 一种用电装置，包括用电主体及如权利要求15所述的电池。
PCT/CN2022/128835 2021-11-11 2022-11-01 电芯卷绕工艺、电芯卷绕装置、电芯、电池以及用电装置 Ceased WO2023083045A1 (zh)

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