WO2025112002A1 - 电极组件及其制备方法、电池单体、电池、用电装置、储能装置 - Google Patents

电极组件及其制备方法、电池单体、电池、用电装置、储能装置 Download PDF

Info

Publication number
WO2025112002A1
WO2025112002A1 PCT/CN2023/135705 CN2023135705W WO2025112002A1 WO 2025112002 A1 WO2025112002 A1 WO 2025112002A1 CN 2023135705 W CN2023135705 W CN 2023135705W WO 2025112002 A1 WO2025112002 A1 WO 2025112002A1
Authority
WO
WIPO (PCT)
Prior art keywords
protective layer
negative electrode
winding
positive electrode
along
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/CN2023/135705
Other languages
English (en)
French (fr)
Inventor
杨道栓
吴永江
林文法
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Contemporary Amperex Technology Co Ltd
Original Assignee
Contemporary Amperex Technology Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Contemporary Amperex Technology Co Ltd filed Critical Contemporary Amperex Technology Co Ltd
Priority to PCT/CN2023/135705 priority Critical patent/WO2025112002A1/zh
Publication of WO2025112002A1 publication Critical patent/WO2025112002A1/zh
Anticipated expiration legal-status Critical
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—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
    • 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
    • H01M50/572—Means for preventing undesired use or discharge
    • H01M50/584—Means for preventing undesired use or discharge for preventing incorrect connections inside or outside the batteries
    • H01M50/59—Means for preventing undesired use or discharge for preventing incorrect connections inside or outside the batteries characterised by the protection means
    • 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

  • New energy batteries are being used more and more widely in life and industry. For example, new energy vehicles equipped with batteries have been widely used. In addition, batteries are also being increasingly used in areas such as energy storage.
  • the batteries can be used to provide power in whole or in part.
  • the batteries can be installed in the energy storage box or directly on the user side.
  • the thermal runaway of battery cells is also an issue that cannot be ignored. Therefore, how to reduce the risk of thermal runaway of battery cells is a technical problem that needs to be solved in battery technology.
  • the present disclosure provides an electrode assembly and a preparation method thereof, a battery cell, a battery, an electrical device, and an energy storage device, which can reduce the risk of thermal runaway of the battery.
  • a first aspect of the present disclosure provides an electrode assembly, comprising: a winding structure, wherein the winding structure is formed by winding a stack including a positive electrode sheet and a negative electrode sheet, an isolating member is sandwiched between the positive electrode sheet and the negative electrode sheet, the winding structure includes a bending zone, the positive electrode sheet includes at least one positive bending portion located in the bending zone, the negative electrode sheet includes at least one negative bending portion located in the bending zone, and along the winding axis direction of the winding structure, both ends of the isolating member extend beyond the positive bending portion and the negative bending portion; and a protective layer attached to the surface of the positive bending portion and/or the surface of the negative bending portion, and along the winding axis direction of the winding structure, at least one end of the protective layer extends beyond the isolating member.
  • the protective layer By attaching a protective layer to the positive bending part and the negative bending part, the risk of breakage and active material shedding when the positive bending part and the negative bending part are bent can be reduced, thereby reducing the risk of thermal runaway of the electrode assembly, the battery cell and even the battery as a whole; the protective layer extends beyond the isolation piece, so that the adhesive tape can completely cover the positive and negative electrode sheets and reliably protect them, and the attachment position of the protective layer can be visually inspected through the exposed part during the battery manufacturing process, so the accuracy of the attachment position can be confirmed in time.
  • the protective layer is attached to the surface of the positive electrode bending portion by pasting or electrostatic adsorption. and/or the surface of the bent portion of the negative electrode.
  • the adhesive method is more firmly attached; the electrostatic adsorption method reduces the possibility of damaging the electrode during attachment.
  • each of the positive electrode bends includes a first concave surface and a first convex surface located on opposite sides
  • the protective layer includes a first protective layer and a second protective layer attached to the first concave surface and the first convex surface, respectively.
  • each of the negative electrode bending portions includes a second concave surface and a second convex surface located on opposite sides
  • the protective layer includes a third protective layer and a fourth protective layer respectively attached to the second concave surface and the second convex surface.
  • the risk of short circuit and thermal runaway caused by the breakage of the negative electrode bend can be further reduced, and the risk of the negative electrode active material layer on both surfaces of the negative electrode bend can be reduced, thereby reducing the impact on the battery capacity and cycle life.
  • the positive electrode sheet includes a positive electrode collector and a positive electrode active material layer disposed on the surface of the positive electrode collector, and the protective layer covers the positive electrode active material layer at the positive electrode bending portion in the positive electrode sheet; and/or, the negative electrode sheet includes a negative electrode collector and a negative electrode active material layer disposed on the surface of the negative electrode collector, and the protective layer covers the negative electrode active material layer at the negative electrode bending portion in the negative electrode sheet.
  • the positive electrode active material layer at the positive electrode bending portion and/or the negative electrode active material layer at the negative electrode bending portion By covering the positive electrode active material layer at the positive electrode bending portion and/or the negative electrode active material layer at the negative electrode bending portion with a protective layer, the positive electrode active material layer and the negative electrode active material layer can be fully protected and the risk of the positive electrode active material layer and the negative electrode active material layer falling off can be reduced.
  • the first edge of the protective layer located at the positive electrode bending portion exceeds the positive electrode active material layer but does not exceed the isolation member
  • the second edge of the protective layer located at the positive electrode bending portion exceeds the isolation member, wherein the first edge is located at one end of the protective layer along the winding axis direction, and the second edge is located at the other end of the protective layer along the winding axis direction; and/or, at the negative electrode bending portion, along the winding axis direction, the third edge of the protective layer located at the negative electrode bending portion exceeds the negative electrode active material layer but does not exceed the isolation member, and the fourth edge of the protective layer located at the negative electrode bending portion exceeds the isolation member, wherein the third edge is located at one end of the protective layer along the winding axis direction, and the fourth edge is located at the other end of the protective layer along the winding axis direction.
  • the protective layer covers both the positive and negative active material layers with only one edge extending beyond the separator, it is possible to visually detect the adhesive position of the protective layer at the positive electrode bend. This reduces the risk of the separator sticking to the roller and causing itself to tear compared to the situation where both edges extend beyond the separator.
  • the positive electrode current collector is provided with a positive electrode tab on one side of the winding axis direction, and the first edge of the protective layer is located on the same side as the positive electrode tab along the winding axis direction; and/or, the negative electrode current collector is provided with a negative electrode tab on one side of the winding axis direction, and the third edge of the protective layer is located on the same side as the negative electrode tab along the winding axis direction.
  • the length of the protective layer beyond the positive electrode bending portion is 4mm to 6mm; and/or, along the winding axis direction, the length of the protective layer beyond the negative electrode bending portion is 4mm to 6mm.
  • the protective layer exceed the specified length of the positive and negative electrode bending parts, the part of the protective layer extending outside can be easily visually observed, thereby making it easy to confirm the position of the protective layer and also facilitating determining the attachment position of the protective layer on the positive and negative electrode sheets.
  • the length of the protective layer exceeding the isolation element is 1 mm to 4 mm.
  • one of the first protective layer and the second protective layer exceeds the other.
  • the first protective layer includes a first end and a second end located at both ends along the winding direction of the winding structure
  • the second protective layer includes a third end and a fourth end located at both ends along the winding direction
  • the third end and the first end are on the same side of the winding direction and are staggered along the winding direction
  • the fourth end and the second end are on the same side of the winding direction and are staggered along the winding direction.
  • the step height of the ends of the stacked protective layers can be reduced compared to non-staggered conditions. Therefore, during the extrusion molding process of the winding structure, a buffer can be formed for the extrusion of the isolation member, reducing the risk of wrinkles on the isolation member, thereby reducing the possibility of the pores of the isolation member being blocked due to wrinkles.
  • the offset length between the third end and the first end along the winding direction is greater than zero and less than or equal to 2 mm; and/or the offset length between the fourth end and the second end along the winding direction is greater than zero and less than or equal to 2 mm.
  • the offset length between the two ends of the first protective layer and the second protective layer on the same side of the winding direction can be greater than zero and less than or equal to 2 mm.
  • the third protective layer includes a fifth end and a sixth end in the winding direction of the winding structure
  • the fourth protective layer includes a seventh end and an eighth end in the winding direction, and the seventh end and the fifth end are connected in the winding direction.
  • the eighth end and the sixth end are on the same side of the winding direction and are staggered along the winding direction, and/or the eighth end and the sixth end are on the same side of the winding direction and are staggered along the winding direction.
  • the step height of the ends of the stacked protective layers can be reduced compared to non-staggered conditions. Therefore, during the extrusion molding process of the winding structure, a buffer can be formed for the extrusion of the isolation member, reducing the risk of wrinkles on the isolation member, thereby reducing the possibility of the pores of the isolation member being blocked due to wrinkles.
  • the offset length between the seventh end and the fifth end along the winding direction is greater than zero and less than or equal to 2 mm; and/or the offset length between the eighth end and the sixth end along the winding direction is greater than zero and less than or equal to 2 mm.
  • the offset length of the third protective layer and the fourth protective layer at both ends on the same side of the winding direction is greater than zero and less than or equal to 2 mm, the risk of wrinkling of the isolation member and the risk of tearing due to roller sticking can be reduced.
  • the winding structure includes a straight area connected to the bending area, and the protective layer extends from at least one end of the winding structure in the winding direction to the junction between the straight area and the bending area or extends to the straight area beyond the junction along the winding direction.
  • the protective layer located at the positive electrode bending portion can cover the positive electrode active material layer in the winding direction, and the positive electrode active material layer is fully protected; the protective layer located at the negative electrode bending portion can cover the negative electrode active material layer in the winding direction, and the negative electrode active material layer is fully protected.
  • the positive electrode sheet includes a plurality of the positive electrode bending portions located in the bending zone and arranged along the stacking direction of the winding structure, and the protective layer is attached to at least the positive electrode bending portion located innermost along the stacking direction; and/or, the negative electrode sheet includes a plurality of the negative electrode bending portions located in the bending zone and arranged along the stacking direction of the winding structure, and the protective layer is attached to at least the negative electrode bending portion located innermost along the stacking direction.
  • the protective layer is attached to at least the innermost positive and negative electrode bends, which can protect the innermost positive and negative electrode bends, and is beneficial to reducing the risks of short circuit and thermal runaway of the entire battery.
  • the material of the protective layer is polyethylene terephthalate, polypropylene, polyethylene, polyimide or non-woven fabric.
  • At least one of the second protective layers at the first convex surface has pores for ion penetration; or, both the first protective layer at the first concave surface and the second protective layer at the first convex surface include a blocking portion for blocking ions.
  • the first protective layer located at the first concave surface and the second protective layer located at the first convex surface have a The pores can protect the positive electrode bending portion from breaking and the risk of the respective active materials falling off, and at the same time reduce the effect of the protective layer attached to the positive electrode bending portion on the positive electrode active material in the positive electrode active material layer at the positive electrode bending portion.
  • the blocking portion for blocking ions on the first protective layer can block the number of lithium ions provided by a part of the positive electrode active material layer, thereby reducing the lithium precipitation phenomenon.
  • the third protective layer located at the second concave surface and the fourth protective layer located at the second convex surface both have pores for ion permeation.
  • the negative electrode bending portion can be protected while reducing lithium plating.
  • the protective layer having pores for ion permeation has an air permeability of 220 ⁇ 70 sec/100 cc.
  • the pores have a pore size of 100 nm to 400 nm.
  • a second aspect of the present disclosure provides a battery cell, comprising: a housing and at least one electrode assembly provided by the first aspect of the present disclosure, wherein the electrode assembly is accommodated in the housing.
  • a third aspect of the present disclosure provides a battery, comprising: a box body and at least one battery cell provided by the second aspect of the present disclosure, wherein the battery cell is accommodated in the box body.
  • a fourth aspect of the present disclosure provides an electrical device, which includes at least one battery cell provided by the second aspect of the present disclosure or the battery provided by the third aspect of the present disclosure for providing electrical energy.
  • a fifth aspect of the present disclosure provides an energy storage device, comprising the battery provided by the third aspect of the present disclosure, wherein the battery is capable of storing electrical energy and providing electrical energy.
  • the sixth aspect of the present disclosure provides a method for preparing an electrode assembly, comprising: providing a positive electrode sheet, a negative electrode sheet and a separator; attaching a protective layer to the positive electrode sheet and/or the negative electrode sheet; stacking and winding the positive electrode sheet, the negative electrode sheet and the separator to form a winding structure, wherein, in the winding structure, an separator is sandwiched between the positive electrode sheet and the negative electrode sheet, the winding structure includes a bending area, the positive electrode sheet includes at least one positive bending portion located in the bending area, the negative electrode sheet includes at least one negative bending portion located in the bending area, along the winding axis direction of the winding structure, two ends of the separator extend beyond the positive bending portion and the negative bending portion, the protective layer is pasted on the surface of the positive bending portion and/or the surface of the negative bending portion, and along the winding axis direction of the winding structure, at least one end of the protective layer extends beyond the separator.
  • FIG1 is a schematic diagram of the structure of a vehicle provided by some embodiments of the present disclosure.
  • FIG2 is a perspective exploded schematic diagram of a battery provided by some embodiments of the present disclosure.
  • FIG3 is a perspective schematic diagram of a battery module provided by some embodiments of the present disclosure.
  • FIG4 is a perspective exploded schematic diagram of a battery cell provided by some embodiments of the present disclosure.
  • FIG5 is a perspective schematic diagram of an electrode assembly provided in some embodiments of the present disclosure.
  • FIG6 is a cross-sectional schematic diagram of an electrode assembly provided in some embodiments of the present disclosure.
  • FIG7 is a partially enlarged schematic diagram of FIG6
  • Fig. 8 is a cross-sectional schematic diagram of the z-z position in Fig. 7;
  • FIG9 is a schematic structural diagram of a positive electrode sheet of an electrode assembly provided by some embodiments of the present disclosure unfolded along a winding direction;
  • FIG10 is a schematic structural diagram of a negative electrode sheet of an electrode assembly provided by some embodiments of the present disclosure unfolded along a winding direction;
  • FIG11 is a cross-sectional schematic diagram of an electrode assembly provided in some other embodiments of the present disclosure.
  • FIG12 is a partially enlarged schematic diagram of FIG11
  • FIG13 is a schematic structural diagram of a positive electrode sheet of an electrode assembly provided by other embodiments of the present disclosure unfolded along a winding direction;
  • FIG14 is a schematic structural diagram of a negative electrode sheet of an electrode assembly provided by other embodiments of the present disclosure unfolded along a winding direction;
  • FIG. 15 is a flow chart of a method for preparing an electrode assembly provided in some embodiments of the present disclosure.
  • 10 electrode assembly 20 housing, 21 shell, 22 end cover, 30 positive electrode terminal, 40 negative electrode terminal, 50 pressure relief mechanism;
  • 11 positive electrode sheet 111 positive electrode bending portion, 112 positive electrode current collector, 112a positive electrode current collector, 112b positive electrode convex portion (positive electrode ear), 113 positive electrode active material layer, 111a first concave surface, 111b first convex surface;
  • 14 protective layer 141 first protective layer, 142 second protective layer, 143 third protective layer, 144 fourth protective layer, 141a first end, 141b second end, 142a third end, 142b fourth end, 143a fifth end, 143b sixth end, 144a seventh end, 144b eighth end, 14a first edge, 14b second edge, 14c third edge, 14d fourth edge;
  • the term "and/or" is only a description of the association relationship of associated objects, indicating that three relationships may exist.
  • a and/or B may represent: A exists alone, A and B exist at the same time, and B exists alone.
  • the character "/" in this article generally indicates that the associated objects before and after are in an "or" relationship.
  • the orientation or position relationship indicated by technical terms such as “length”, “width”, “thickness”, “inside”, “outside”, “stacking direction”, “winding axis direction”, etc. is based on the orientation or position relationship shown in the accompanying drawings. It is only for the convenience of describing the embodiments of the present disclosure and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed, operated or used in a specific orientation. Therefore, it should not be understood as a limitation on the embodiments of the present disclosure.
  • contact should be understood in a broad sense, which may be direct contact, contact through an intermediate medium layer, or a basic contact between two contacting layers. There can be no interaction force between the two contacting parts, or there can be interaction force between the two contacting parts.
  • New energy batteries are increasingly used in life and industry.
  • New energy batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but are also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars, as well as aerospace and other fields. With the continuous expansion of the application field of new energy batteries, the market demand is also constantly expanding.
  • the wound electrode assembly needs to be extruded and shaped to eliminate the wrinkles of the separator and the internal air, reduce the risk of short circuit, and improve the surface flatness for easy shell insertion.
  • the active material on the pole piece at the bend due to winding may fall off, and there may even be a risk of the pole piece breaking at the bend.
  • the falling off of the active material on the pole piece is called powder loss.
  • Pole piece breakage or the falling off of active material on the pole piece can lead to thermal runaway of the battery. Pole piece breakage can easily puncture the separator, which may cause a short circuit between the adjacent positive and negative pole pieces, leading to thermal runaway problems and battery explosion and fire.
  • the falling off of active material on the pole piece not only affects the battery capacity, but may also lead to lithium precipitation.
  • lithium plating is likely to occur. Lithium plating not only reduces the performance of lithium-ion batteries and significantly shortens the cycle life, but also limits the fast charging capacity of lithium-ion batteries.
  • the precipitated lithium metal is very active and can react with the electrolyte at a relatively low temperature, causing the starting temperature of the battery's self-heat generation to decrease and the self-heat generation rate to increase, posing a risk of thermal runaway.
  • the released lithium ions can form lithium dendrites on the surface of the negative electrode plate, and the lithium dendrites can easily pierce the separator, causing a short circuit between the adjacent positive and negative electrode plates, posing a risk of thermal runaway.
  • the winding electrode assembly (bare battery cell) is prone to lithium deposition in its bending area.
  • the main reason for the lithium deposition is that the positive electrode sheet and the negative electrode sheet located in the bending area need to be bent, and the negative electrode sheet located inside the positive electrode sheet is prone to insufficient lithium embedding space, which may cause the negative electrode sheet's negative electrode active material layer to have less lithium embedding sites than the positive electrode sheet's adjacent positive electrode sheet's positive electrode active material layer can provide, thereby causing lithium deposition.
  • the surfaces of the positive electrode sheet and the negative electrode sheet in the bending area will be subjected to a large tensile force, especially the innermost positive electrode sheet and the innermost negative electrode sheet are subjected to a greater tensile force, which may easily cause the respective active material layers on the positive electrode sheet and the negative electrode sheet to fall off, affecting the battery capacity, and may even cause the positive electrode sheet and the negative electrode sheet in the bending area to break, leading to the risk of thermal runaway of the battery.
  • a protective layer such as glue
  • glue a protective layer
  • the inventors tried to analyze the reasons and believed that the possible reasons are: After gluing, the pole piece is wound. The glue is wrapped in the winding structure, and it is impossible to determine whether the glue sticking position is exactly in the bending zone. If the glue sticking position is not in the bending zone, the risk of powder loss and fracture in the bending zone still exists. Therefore, if the glue sticking position cannot be accurately judged, there is still a risk of short circuit and thermal runaway caused by powder loss and pole piece fracture.
  • an embodiment of the present disclosure provides an electrode assembly, including: a winding structure, which is formed by winding a stack including a positive electrode sheet and a negative electrode sheet, an isolating member is sandwiched between the positive electrode sheet and the negative electrode sheet, the winding structure includes a bending zone, the positive electrode sheet includes at least one positive bending portion located in the bending zone, the negative electrode sheet includes at least one negative bending portion located in the bending zone, and along the winding axis direction of the winding structure, both ends of the isolating member extend beyond the positive bending portion and the negative bending portion; and a protective layer attached to the surface of the positive bending portion and/or the surface of the negative bending portion, and along the winding axis direction of the winding structure, at least one end of the protective layer extends beyond the isolating member.
  • the protective layer By attaching the protective layer to the surface of the positive electrode bending portion and/or the surface of the negative electrode bending portion, the risk of breakage of the positive electrode sheet and/or the negative electrode sheet and the shedding of the active material in the bending area can be reduced, thereby reducing the risk of thermal runaway of the electrode assembly, the battery cell and even the battery as a whole; and, by extending the protective layer beyond the isolation member, the protective layer can completely cover the positive and negative electrode sheets to provide reliable protection for them, and the pasting position of the protective layer can be visually detected during the battery manufacturing process (for example, during the winding process), thereby enabling an accurate judgment of the pasting position.
  • the electrode assembly of the embodiment of the present disclosure is applicable to a battery cell or a battery.
  • the battery of the embodiment of the present disclosure can be used in, but is not limited to, energy storage power supply systems, vehicles, ships, aircraft and other electrical devices.
  • the batteries of the embodiments of the present disclosure can also be grouped into multiple groups and used as a battery pack.
  • the battery pack can also be used in, but not limited to, energy storage power supply systems, vehicles, ships, aircraft and other electrical devices.
  • the embodiments of the present disclosure provide an electric device including the above-mentioned battery or battery pack for providing electric energy
  • the electric device may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft, etc.
  • the electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc.
  • the spacecraft may include an airplane, a rocket, a space shuttle, a spacecraft, etc.
  • the embodiments of the present disclosure also provide an energy storage device including the above-mentioned battery or battery pack.
  • the energy storage device may be, but is not limited to, an energy storage box, an energy storage container, etc.
  • the electric device of one embodiment of the present disclosure is taken as a vehicle 1000 as an example for description.
  • the following is a description with reference to the accompanying drawings.
  • FIG1 is a schematic diagram of the structure of a vehicle 1000 provided in some embodiments of the present disclosure.
  • the vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle.
  • the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended range vehicle.
  • a battery 100 is disposed inside the vehicle 1000.
  • the battery 100 may be disposed at the bottom of the vehicle 1000.
  • the battery 100 can be used to power the vehicle 1000, for example, the battery 100 can be used as an operating power source for the vehicle 1000.
  • the vehicle 1000 can also include a controller 200 and a motor 300, and the controller 200 is used to control the battery 100 to power the motor 300, for example, for starting, navigating, and driving the vehicle 1000.
  • the battery 100 can be used not only as an operating power source for the vehicle 1000, but also as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.
  • Fig. 2 is a perspective exploded schematic diagram of a battery provided by some embodiments of the present disclosure.
  • the battery 100 includes a housing 110 and a battery cell (not shown in Fig. 2 ), and the battery cell is accommodated in the housing 110 .
  • the box 110 is used to accommodate battery cells, and the box 110 can be of various structures.
  • the box 110 can include a first box portion 120 and a second box portion 130, the first box portion 120 and the second box portion 130 cover each other, and the first box portion 120 and the second box portion 130 jointly define a storage space 150 for accommodating battery cells.
  • the second box portion 130 can be a hollow structure with one end open, the first box portion 120 is a plate-like structure, and the first box portion 120 covers the open side of the second box portion 130 to form the box 110 with the storage space 150; the first box portion 120 and the second box portion 130 can also be hollow structures with one side open, and the open side of the first box portion 120 covers the open side of the second box portion 130 to form the box 110 with the storage space 150.
  • the first box body 120 and the second box body 130 can be in various shapes, such as a cylinder, a cuboid, etc.
  • a sealing member such as a sealant, a sealing ring, etc., may also be provided between the first box body 120 and the second box body 130 .
  • the first box body portion 120 covers the top of the second box body portion 130
  • the first box body portion 120 can also be referred to as an upper box cover
  • the second box body portion 130 can also be referred to as a lower box body.
  • the battery 100 there can be one or more battery cells. If there are multiple battery cells, the multiple battery cells can be connected in series, in parallel, or in a mixed connection.
  • a mixed connection means that the multiple battery cells are connected in series and in parallel.
  • the multiple battery cells can be directly connected in series, in parallel, or in a mixed connection, and then the whole formed by the multiple battery cells is accommodated in the box 110; of course, multiple battery cells can also be connected in series, in parallel, or in a mixed connection to form a battery module 140, and the multiple battery modules 140 are then connected in series, in parallel, or in a mixed connection to form a whole, and accommodated in the box 110.
  • FIG3 is a three-dimensional schematic diagram of a battery module provided by some embodiments of the present disclosure. As shown in FIG3, in some embodiments, there are multiple battery cells 160, and multiple battery cells 160 are first connected in series, in parallel, or in mixed connection to form a battery module 140. Multiple battery modules 140 are then connected in series, in parallel, or in mixed connection to form a whole, and are accommodated in a box.
  • the multiple battery cells 160 in the battery module 140 may be electrically connected via a busbar component to achieve parallel connection, series connection, or mixed connection of the multiple battery cells 160 in the battery module 140 .
  • FIG. 4 is a perspective exploded schematic diagram of a battery cell provided in some embodiments of the present disclosure
  • FIG. 5 is a perspective schematic diagram of an electrode assembly provided in some embodiments of the present disclosure.
  • a battery cell 160 provided in an embodiment of the present disclosure
  • the electrode assembly 10 and the housing 20 are included.
  • the electrode assembly 10 is accommodated in the housing 20 .
  • the battery cell 160 may be a secondary battery.
  • a secondary battery refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.
  • the battery cell 160 may be a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel hydrogen battery, a nickel cadmium battery, a lead storage battery, etc., but the embodiments of the present disclosure are not limited thereto.
  • the electrode assembly 10 includes a positive electrode sheet, a negative electrode sheet, and a separator.
  • active ions such as lithium ions
  • the separator is arranged between the positive electrode sheet and the negative electrode sheet to prevent the positive electrode sheet and the negative electrode sheet from short-circuiting, while allowing the active ions to pass through.
  • the electrode assembly is provided with tabs, which can lead current out of the electrode assembly.
  • the tabs include a positive tab and a negative tab.
  • the housing 20 can also be used to contain electrolytes, such as electrolytes.
  • the housing 20 can be in various structural forms.
  • the housing can be a steel housing, an aluminum housing, a plastic housing (such as polypropylene), a composite metal housing (such as a copper-aluminum composite housing), or an aluminum-plastic film.
  • the housing 20 may include a shell 21 and an end cap 22, wherein the shell 21 is a hollow structure with one side open, and the end cap 22 covers the opening of the shell 21 and forms a sealed connection to form a sealed space for accommodating the electrode assembly 10 and the electrolyte.
  • the shell 21 can be in various shapes, for example, a cube, a cuboid, etc.
  • the shape of the shell 21 can be determined according to the specific shape of the electrode assembly 10.
  • the end cap 22 can be in various structures, for example, the end cap 22 is a plate-like structure, a hollow structure with one end open, etc. Exemplarily, in FIG. 4 , the shell 21 is a cuboid structure, the end cap 22 is a plate-like structure, and the end cap 22 covers the opening at the top of the shell 21.
  • the battery cell 160 may further include a positive electrode terminal 30, a negative electrode terminal 40, and a pressure relief mechanism 50, which are all mounted on the end cap 22.
  • the positive electrode terminal 30 and the negative electrode terminal 40 are both used to be electrically connected to the electrode assembly 10 to output the electrical energy generated by the electrode assembly 10.
  • the pressure relief mechanism 50 is used to release the pressure inside the battery cell 160 when the internal pressure or temperature of the battery cell 160 reaches a predetermined value.
  • the pressure relief mechanism 50 is located between the positive electrode terminal 30 and the negative electrode terminal 40 , and the pressure relief mechanism 50 may be a component such as an explosion-proof valve, an explosion-proof disk, an air valve, a pressure relief valve, or a safety valve.
  • the housing 20 may also be other structures.
  • the housing 20 includes a shell 21 and two end caps 22.
  • the shell 21 is a hollow structure with two opposite openings.
  • One end cap 22 covers one opening of the shell 21.
  • the positive electrode terminal 30 and the negative electrode terminal 40 are connected and sealed to form a sealed space for accommodating the electrode assembly 10 and the electrolyte.
  • the positive electrode terminal 30 and the negative electrode terminal 40 can be installed on the same end cap 22 or on different end caps 22; the pressure relief mechanism 50 can be installed on one end cap 22 or on both end caps 22.
  • the battery cell 160 there may be one or more electrode assemblies 10 contained in the housing 20.
  • FIG. 5 is a perspective schematic diagram of an electrode assembly provided in some embodiments of the present disclosure.
  • FIG. 6 is a cross-sectional schematic diagram of an electrode assembly provided in some embodiments of the present disclosure.
  • FIG. 7 is a partially enlarged schematic diagram of FIG. 6.
  • FIG. 8 is a cross-sectional schematic diagram of the z-z position in FIG. 7.
  • FIG. 9 is a structural schematic diagram of a positive electrode sheet of an electrode assembly provided in some embodiments of the present disclosure unfolded along a winding direction.
  • FIG. 10 is a structural schematic diagram of a negative electrode sheet of an electrode assembly provided in some embodiments of the present disclosure unfolded along a winding direction.
  • the electrode assembly 10 of the embodiment of the present disclosure includes a winding structure and a protective layer.
  • the winding structure is formed by winding a stack including a positive electrode sheet 11 and a negative electrode sheet 12, and a separator 13 is sandwiched between the positive electrode sheet 11 and the negative electrode sheet 12.
  • the winding structure includes a bending area A
  • the positive electrode sheet 11 includes at least one positive bending portion 111 located in the bending area A
  • the negative electrode sheet 12 includes at least one negative bending portion 121 located in the bending area A.
  • the two ends of the separator 13 exceed the positive bending portion 111 and the negative bending portion 121; the protective layer 14 is attached to the surface of the positive bending portion 111 and/or the surface of the negative bending portion 112, and along the winding axis K direction of the winding structure, at least one end of the protective layer 14 exceeds the separator 13.
  • the positive electrode sheet 11 includes a positive current collector 112 and a positive active material layer 113, wherein the positive active material layer 113 is coated on the surface of the positive current collector 112; the positive current collector 112 includes a positive current collector 112a and a positive convex portion 112b protruding from the positive current collector 112a, wherein the positive current collector 112a is coated with the positive active material layer 113, and at least part of the positive convex portion 112b is not coated with the positive active material layer 113, and the positive convex portion 112b serves as a positive electrode tab.
  • the positive convex portion 112b may be a positive electrode tab 112b.
  • the material of the positive current collector 112 may be aluminum (aluminum foil), and the positive active material layer 113 includes a positive active material, which may be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganate.
  • the negative electrode sheet 12 includes a negative electrode current collector 122 and a negative electrode active material layer 123, wherein the negative electrode active material layer 123 is coated on the surface of the negative electrode current collector 122;
  • the negative electrode current collector 122 includes a negative electrode current collector portion 122a and a negative electrode protrusion 122b protruding from the negative electrode current collector portion 122a, wherein the negative electrode current collector portion 122a is coated with the negative electrode active material layer 123, and at least a portion of the negative electrode protrusion 122b is not coated with the negative electrode active material layer 123, and the negative electrode protrusion 122b serves as a negative electrode tab.
  • the negative electrode protrusion 122b may be a negative electrode tab 122b.
  • the material of the negative electrode current collector 122 may be copper (copper foil), and the negative electrode active material layer 123 includes a negative electrode active material, and the negative electrode active material may be carbon (e.g., graphite carbon) or silicon, etc.
  • the number of positive electrode tabs 112b is multiple and they are stacked together, and the number of negative electrode tabs 122b is multiple and they are stacked together.
  • the positive electrode sheet 11 and the negative electrode sheet 12 are stacked on each other to form a stack.
  • the stack is wound around the winding axis K for more than two turns to form a winding structure.
  • the extension direction of the winding axis K is perpendicular to the winding direction C of the winding structure and the stacking direction E (see Figure 8).
  • An isolator 13 is sandwiched between each adjacent positive electrode sheet 11 and negative electrode sheet 12, and the isolator 13 is used to isolate the positive electrode sheet 11 from the negative electrode sheet 12 to reduce the risk of short circuit between the positive electrode sheet 11 and the negative electrode sheet 12.
  • the material of the isolator 13 can be PP (polypropylene) or PE (polyethylene).
  • the positive electrode sheet 11, the negative electrode sheet 12 and the separator 13 can all be strip-shaped structures.
  • the positive electrode sheet 11, the separator 13, the negative electrode sheet 12 and the separator 13 can be stacked in sequence, and then wound around the winding axis K from the inside to the outside for more than two turns to form a winding structure.
  • the winding structure is wound in a clockwise direction.
  • the winding direction can also be counterclockwise.
  • the winding structure includes a bending zone A, which is an area on the positive electrode sheet 11 and the negative electrode sheet 12 where the bending structure is located, and is an example of a bending zone.
  • the positive bending portion 111 and the negative bending portion 121 are alternately distributed along the stacking direction E of the winding structure, that is, in the bending zone A, the positive bending portion 111, the negative bending portion 121, the positive bending portion 111, the negative bending portion 121...are arranged in sequence from the inside to the outside, wherein the inside is closer to the winding axis K than the outside, and the stacking direction E is the layer thickness direction of the winding structure.
  • the innermost positive bending portion 111 is located outside the innermost negative bending portion 121.
  • the shape of the positive bending portion 111 and the negative bending portion 121 can be generally arc-shaped.
  • the two ends of the separator 13 exceed the positive bending portion 111 and the negative bending portion 121. That is, along the winding axis direction K, the two ends of the separator 13 respectively exceed the two ends of the positive bending portion 111, and, along the winding axis direction K, the two ends of the separator 13 respectively exceed the two ends of the negative bending portion 121.
  • the edge of the positive bending portion 111 and the edge of the negative bending portion 121 do not exceed the end of the separator 13 and have a certain amount of indentation.
  • the separator 13 can completely cover the positive bending portion 111 and the negative bending portion 121, effectively reducing the risk of short circuit between the positive electrode sheet 11 and the negative electrode sheet 12.
  • the protective layer 14 is attached to the surface of the positive electrode bend 111 and/or the surface of the negative electrode bend 112.
  • the protective layer 14 may be attached to the surface of the positive electrode bend 111 in the positive electrode bend 111 and the negative electrode bend 121 as shown in FIG6; or, the protective layer 14 is attached to the surface of the negative electrode bend 121 in the positive electrode bend 111 and the negative electrode bend 121; or, as shown in FIG11, the protective layer 14 is attached to the surface of the positive electrode bend 111 and the surface of the negative electrode bend 121.
  • the surface of the positive electrode bend 111 may be the surface of the positive active material layer 113 at the positive electrode bend 111 in the positive electrode sheet 11.
  • the surface of the negative electrode bent portion 121 may be the surface of the negative electrode active material layer 123 at the negative electrode bent portion 121 in the negative electrode sheet 12 .
  • the protective layer 14 is attached to the surface of the positive bending portion 111 and/or the surface of the negative bending portion 121 by pasting or electrostatic adsorption. Wherein, the protective layer 14 is attached to the surface of the positive bending portion 111 and/or the surface of the negative bending portion 121 by pasting, and it can be that the protective layer 14 itself has an adhesive layer, so that it is pasted to the surface of the positive bending portion 111 and/or the surface of the negative bending portion 121 through the adhesive layer.
  • the protective layer 14 is pasted to the surface of the positive bending portion 111 and/or the surface of the negative bending portion 121 through an adhesive body, and the adhesive body can be a colloid or an adhesive layer coated on the surface of the positive bending portion 111 and/or the surface of the negative bending portion 121.
  • At least one end of the protective layer 14 extends beyond the isolation member 13 .
  • One end of the protective layer 14 may extend beyond the isolation member 13
  • the other end of the protective layer 14 may extend beyond the isolation member 13 or may not extend beyond the isolation member 13 .
  • the protective layer 14 may extend beyond the isolating member 13 in the direction of the winding axis K of the winding structure, and the end of the protective layer 14 may extend beyond the edge of the isolating member 13 on the same side as the end of the protective layer 14.
  • the protective layer 14 may not extend beyond the isolating member 13 in the direction of the winding axis K of the winding structure, and the end of the protective layer 14 may be retracted from the edge of the isolating member 13 on the same side as the end of the protective layer 14. As for the retracted position, it may be located between the same side edge of the pole piece and the isolating member 13, or it may be substantially flush with the edge of the pole piece.
  • the positive electrode bend 111 and the negative electrode bend 121 generate stress concentration during the bending process and may cause the risk of fracture and the shedding of active materials on their respective surfaces, thereby posing a risk of thermal runaway of the battery.
  • the disclosed embodiment attaches a protective layer 14 to the positive electrode bend 111 and the negative electrode bend 121, thereby reducing the risk of fracture and active material shedding when the positive electrode bend 111 and the negative electrode bend 121 are bent, thereby reducing the risk of thermal runaway of the electrode assembly, the battery cell, and even the battery as a whole.
  • the protective layer 14 extends beyond the isolation member 13, so that the protective layer can completely cover the positive and negative electrode sheets and reliably protect them, and the attachment position of the protective layer 14 can be visually observed during the battery manufacturing process (for example, during the winding process), and the accuracy of the attachment position can be confirmed in time.
  • the material of the protective layer 14 can be polyethylene terephthalate, polypropylene, polyethylene, polyimide or non-woven fabric.
  • the first edge 14a of the protective layer 14 located at the positive electrode bending portion 111 exceeds the positive electrode active material layer 113 but does not exceed the separator 13, and the second edge 14b of the protective layer 14 located at the positive electrode bending portion 111 exceeds the separator 13, wherein the first edge 14a is located at one end of the protective layer 14 along the winding axis direction K, and the second edge 14b is located at the other end of the protective layer 14 along the winding axis direction K.
  • the first edge 14a of the protective layer 14 located at the positive electrode bending portion 111 exceeds the positive electrode active material layer 113 but does not exceed the separator 13. It can be that along the winding axis direction K, the first edge 14a is located at the edge of the positive electrode active material layer 113 on the same side. and the edge of the separator 13.
  • the positive current collector 112a is coated with the positive active material layer 113, and the region of the positive current collector 112a that is not coated with the positive active material layer 112a is coated with the insulating layer 114, the insulating layer 114 is located on one side of the positive active material layer 113 close to the positive convex portion 112b (positive electrode ear), and is located between the edge of the positive active material layer 113 and the edge of the separator 13 on the same side, and the first edge 14a may be located in the insulating layer 114.
  • the surface of the protective layer 14 extending beyond the separator 13 is sticky, and there is a possibility of sticking to the roller during the winding process, resulting in the risk of the protective layer 14 being torn.
  • the first edge 14a of the protective layer 14 located at the positive electrode bending portion 111 exceeds the positive electrode active material layer 113 but does not exceed the isolation member 13, and the second edge 14b of the protective layer 14 located at the positive electrode bending portion 111 exceeds the isolation member 13.
  • the protective layer 14 covers the positive electrode active material layer 113, only one edge exceeds the isolation member 13. It can be visually observed that the protective layer 14 is located at the pasting position of the positive electrode bending portion 111. Compared with both edges exceeding the isolation member 13, the risk of the isolation member 13 sticking to the roller and causing itself to tear can be reduced.
  • the third edge 14c of the protective layer 14 located at the negative electrode bend 121 exceeds the negative electrode active material layer 123 but does not exceed the isolation member 13
  • the fourth edge 14d of the protective layer 14 located at the negative electrode bend exceeds the isolation member, wherein the third edge 14c is located at one end of the protective layer 14 along the winding axis direction k, and the fourth edge 14d is located at the other end of the protective layer 14 along the winding axis direction K.
  • the third edge 14c of the protective layer 14 located at the negative electrode bending portion 121 exceeds the negative electrode active material layer 123 but does not exceed the separator 13. It can be that along the winding axis direction K, the third edge 14c is located between the edge of the negative electrode active material layer 123 and the edge of the separator 13 on the same side.
  • the third edge 14c is located between the edge of the negative electrode active material layer 123 and the edge of the separator 13 on the same side.
  • only a part of the negative electrode current collector 122a is coated with the negative electrode active material layer 123, and the area of the negative electrode current collector 122a that is not coated with the negative electrode active material layer 123 is coated with the insulating layer 124.
  • the insulating layer 124 is located on one side of the negative electrode active material layer 123 close to the negative electrode protrusion 122b (negative electrode ear), and is located between the edge of the negative electrode active material layer 123 and the edge of the separator 13 on the same side.
  • the third edge 14c can be located in the insulating layer 124.
  • the third edge 14c of the protective layer 14 located at the negative electrode bend 121 exceeds the negative electrode active material layer 123 but does not exceed the isolation member 13, and the fourth edge 14d of the protective layer 14 located at the negative electrode bend 121 exceeds the isolation member 13.
  • the protective layer 14 covers the negative electrode active material layer 123, only one edge exceeds the isolation member 13. It can be visually observed that the protective layer 14 is located at the pasting position of the negative electrode bend 121. Compared with both edges exceeding the isolation member 13, the risk of the isolation member 13 sticking to the roller and causing itself to tear can be reduced.
  • the length d1 of the protective layer 14 beyond the separator 13 is 1 mm to 4 mm along the winding axis direction K.
  • the length d1 of the protective layer 14 beyond the separator 13 at the positive electrode bending portion 111 can be 1 mm to 4 mm, and the length d1 of the protective layer 14 beyond the separator 13 at the negative electrode bending portion 121 can be 1 mm to 4 mm.
  • the length d1 can be 1 mm, 2 mm, 3 mm, or 4 mm.
  • the length d1 of the protective layer 14 extending beyond the separator 13 is controlled to be between 1 mm and 4 mm, which can facilitate visual inspection of the pasting position of the protective layer 14 and reduce the risk of the protective layer 14 being torn due to sticking to the roller.
  • the length d2 of the protective layer 14 at the positive electrode bend 111 beyond the positive electrode bend 111 is 4 mm to 6 mm. And/or, along the winding axis direction K, the length d2 of the protective layer 14 at the negative electrode bend 121 beyond the negative electrode bend 121 is 4 mm to 6 mm.
  • the length d2 includes the length of the spacer 13 extending beyond the edge of the pole piece and the length of the protection layer 14 extending beyond the spacer 13 .
  • the protective layer 14 can be attached to the electrode first, and then the winding is performed.
  • the edge of the electrode is smoother than the edge of the separator, and it is easier to measure the excess size of the protective layer 14.
  • the protective layer 14 is attached to the electrode, before the winding, it is also convenient to measure the size of the protective layer 14 exceeding the electrode. Therefore, the excess length of the protective layer 14 exceeding the separator 13 can be controlled by the length of the protective layer 14 exceeding the positive electrode bending portion 111 and/or the negative electrode bending portion 121, which can improve the attachment accuracy of the protective layer 14.
  • a positive electrode tab 112 b is provided on one side of the positive electrode current collector 112 a along the winding axis direction K, and a first edge 14 a of the protective layer 14 is located on the same side as the positive electrode tab 112 b along the winding axis direction K. That is, the first edge 14 a located on the same side as the positive electrode tab 112 b does not extend beyond the separator 13 .
  • a negative electrode tab 122 b is provided on one side of the negative electrode current collector 122 a along the winding axis direction K, and the third edge 14 c of the protective layer 14 is located on the same side as the negative electrode tab 122 b along the winding axis direction K. That is, the third edge 14 a located on the same side as the negative electrode tab 122 b does not extend beyond the separator 13 .
  • the detection equipment is usually provided on the side of the pole ear (positive pole ear 112b, negative pole ear 122b).
  • the detection equipment can be a sensor for detecting the pole ear, which can be used to determine whether the pole ear is bent. If it is bent, it is considered unqualified. If the edge of the protective layer 14 (first edge 14a, third edge 14c) on the same side of the pole ear exceeds the separator 13, when the exceeding part of the protective layer 14 passes through the sensor, it may cause the sensor to misreport, that is, mistaking the qualified positive pole ear for unqualified. Therefore, in the embodiment of the present disclosure, the risk of false alarm of the detection equipment on the side of the pole ear can be avoided by not exceeding the separator 13 at the edge of the protective layer 14 on the same side of the pole ear.
  • the protective layer 14 may cover the positive electrode active material layer 113 on one side (the first concave surface 111a or the first convex surface 111b) or the positive electrode active material layer 113 on both sides (the first concave surface 111a and the first convex surface 111b) of the positive electrode bending portion 111 in the positive electrode tab 11. Moreover, the protective layer 14 may also cover the negative electrode active material layer 123 on one side (the second concave surface 121a or the second convex surface 121b) or the negative electrode active material layer 123 on both sides (the second concave surface 121a and the second convex surface 121b) of the negative electrode bending portion 121 in the negative electrode tab 12.
  • FIG11 is a cross-sectional schematic diagram of an electrode assembly provided in some other embodiments of the present disclosure.
  • FIG12 is a partially enlarged view of FIG11 Schematic diagram.
  • each positive electrode bending portion 111 includes a first concave surface 111a and a first convex surface 111b located on opposite sides, and the protective layer 14 includes a first protective layer 141 and a second protective layer 142 respectively attached to the first concave surface 111a and the first convex surface 111b.
  • the stacking direction E of the winding structure may be the thickness direction of the positive electrode bending portion 111.
  • a plurality of positive electrode bending portions 111 may be arranged along the stacking direction E, and each positive electrode bending portion 111 includes a first concave surface 111a and a first convex surface 111b located on opposite sides.
  • the first concave surface 111a is a side of the positive electrode bending portion 111 where the arc is concave inward
  • the first convex surface 111b is a side of the positive electrode bending portion 111 where the arc is convex outward.
  • the first concave surface 111a is closer to the winding axis than the first convex surface 111b.
  • the disclosed embodiment further reduces the risk of the positive electrode bending portion 111 breaking by attaching a protective layer 14 to the first concave surface 111a and the first convex surface 111b on both the front and back sides of the positive electrode bending portion 111, and can reduce the risk of the positive electrode active material layer falling off on both surfaces of the positive electrode bending portion 111, thereby reducing the adverse effects on the battery capacity and reducing the risk of thermal runaway of the battery.
  • the first protection layer 141 and the second protection layer 142 may be attached to the first concave surface 111a and the first convex surface 111b of each positive electrode bending portion 111, respectively. In this way, the plurality of positive electrode bending portions 111 may be fully protected.
  • the innermost positive electrode bend 111 in the stacking direction E is subjected to a greater tensile force than other positive electrode bends 111, it is more likely to cause breakage or fall-off of the positive electrode active material layer.
  • the first concave surface 111a and the first convex surface 111b of the innermost positive electrode bend 111 in the stacking direction E may be respectively attached with a first protective layer 141 and a second protective layer 142. In this way, the innermost positive electrode bend 111 is effectively protected.
  • At least one end of the first protective layer 141 and the second protective layer 142 exceeds the other. That is, along the winding axis direction K, the ends of the first protective layer 141 and the second protective layer 142 on the same side are staggered (misaligned) with each other.
  • one end of the first protective layer 141 on the same side exceeds one end of the second protective layer 142; or, along the winding axis direction K, one end of the second protective layer 142 on the same side exceeds one end of the first protective layer 141; or, along the winding axis direction K, both ends of the first protective layer 141 respectively exceed both ends of the second protective layer 142 on the same side; or, along the winding axis direction K, both ends of the second protective layer 142 respectively exceed both ends of the first protective layer 141 on the same side.
  • the overhanging dimension of one of the first protective layer 141 and the second protective layer 142 over the other may be 0-4 mm.
  • the overhanging dimension may be 0 mm, 1 mm, 2 mm, 3 mm, or 4 mm.
  • each negative electrode bent portion 121 includes a second concave surface 121a and a second convex surface 121b located on opposite sides
  • the protective layer 14 includes a second concave surface 121a and a second convex surface 121b attached to the second concave surface 121a and the second convex surface 121b, respectively.
  • a third protective layer 143 and a fourth protective layer 144 are provided.
  • a plurality of negative electrode bends 121 may be arranged along the stacking direction E, and the plurality of negative electrode bends 121 and the plurality of positive electrode bends 111 are alternately distributed along the stacking direction E, and each negative electrode bend 121 includes a second concave surface 121a and a second convex surface 121b located on opposite sides.
  • the second concave surface 121a is a side of the arc of the negative electrode bend 121 that is concave inward
  • the second convex surface 121b is a side of the arc of the negative electrode bend 121 that is convex outward.
  • the second concave surface 121a is closer to the winding axis than the second convex surface 121b.
  • the disclosed embodiment further reduces the risk of the negative electrode bend 121 breaking by attaching a protective layer 14 to the second concave surface 121a and the second convex surface 121b on both the front and back sides of the negative electrode bend 121, and can reduce the risk of the negative electrode active material layer falling off on both surfaces of the negative electrode bend 121, thereby reducing the adverse effects on the battery capacity and reducing the risk of thermal runaway of the battery.
  • the third protection layer 143 and the fourth protection layer 144 may be attached to the second concave surface 121a and the second convex surface 121b of each negative electrode bending portion 121, respectively. In this way, multiple negative electrode bending portions 121 may be fully protected.
  • the innermost negative electrode bent portion 121 in the stacking direction E is subjected to a greater tensile force than other negative electrode bent portions 121 , it is more likely to be broken or the positive electrode active material layer to fall off.
  • the third protective layer 143 and the fourth protective layer 144 may be attached to the second concave surface 121a and the second convex surface 121b of the innermost negative electrode bending portion 121 in the stacking direction E. In this way, the innermost negative electrode bending portion 121 is effectively protected.
  • the first protective layer 141 includes a first end 141a and a second end 141b along the winding direction C of the winding structure
  • the second protective layer 142 includes a third end 142a and a fourth end 142b in the winding direction C
  • the third end 142a and the first end 141a are located on the same side of the winding direction C and are staggered along the winding direction C
  • the fourth end 142b and the second end 141b are located on the same side of the winding direction C and are staggered along the winding direction C.
  • the third end 142a and the first end 141a are staggered along the winding direction C, which means that the third end 142a and the first end 141a are not at the same position along the winding direction C.
  • the third end 142a exceeds the first end 141a; or in other words, the first end 141a extends in a counterclockwise direction compared to the third end 142a.
  • the first end 141a may also exceed the third end 142a.
  • the fourth end 142b and the second end 141b are staggered along the winding direction C, which means that the fourth end 142b and the second end 141b are not at the same position along the winding direction C.
  • the fourth end 142b exceeds the second end 141b; or, in other words, the fourth end 142b extends in a clockwise direction compared to the second end 141b.
  • the second end 141b may also exceed the fourth end 142b.
  • the first protective layer 141 and the second protective layer 142 may be staggered at one end on the same side of the winding direction C; or As shown in FIG12 , the two ends of the first protective layer 141 and the second protective layer 142 on the same side of the winding direction C are staggered.
  • the third end 142a is staggered with the first end 141a
  • the fourth end 142b is not staggered with the second end 141b
  • the fourth end 142b is staggered with the second end 141b
  • the third end 142a is not staggered with the first end 141a
  • the third end 142a is staggered with the first end 141a
  • the fourth end 142b is staggered with the second end 141b.
  • the end of the first protective layer 141 and the end of the second protective layer 142 respectively form steps with the surface of the positive electrode plate 11.
  • the greater the height difference of the step the more obvious the extrusion of the separator 13, which is easy to cause the separator 13 to wrinkle, thereby blocking the pores in the separator 13, and even there is a risk of breaking the separator.
  • the two ends of the same side of the first protective layer 141 and the second protective layer 142 are staggered from each other, which can reduce the step height of the end of each protective layer after stacking compared to non-staggered. Therefore, during the extrusion molding process of the winding structure, it can form a buffer for the extrusion of the separator 13, reduce the risk of wrinkling of the separator 13, and thus reduce the blocking of the pores of the separator 13 caused by wrinkles.
  • the third protective layer 143 includes a fifth end 143a and a sixth end 143b in the winding direction C of the winding structure
  • the fourth protective layer 144 includes a seventh end 144a and an eighth end 144b in the winding direction C
  • the seventh end 144a and the fifth end 143a are located on the same side of the winding direction C and are staggered along the winding direction C
  • the eighth end 144b and the sixth end 143b are on the same side of the winding direction C and are staggered along the winding direction C.
  • the third protective layer 143 and the fourth protective layer 144 may have ends on the same side along the winding direction C that are staggered with each other; or the third protective layer 143 and the fourth protective layer 144 may have ends on both sides along the winding direction C that are staggered with each other.
  • the seventh end 144a and the fifth end 143a are staggered with each other, and the eighth end 144b and the sixth end 143b are not staggered with each other; or, the eighth end 144b and the sixth end 143b are staggered with each other, and the seventh end 144a and the fifth end 143a are not staggered with each other; or, the seventh end 144a and the fifth end 143a are staggered with each other, and the eighth end 144b and the sixth end 143b are staggered with each other.
  • the step height of the ends of the stacked protective layers can be reduced compared to the case where the two ends are not staggered. Therefore, during the extrusion molding process of the winding structure, a buffer can be formed for the extrusion of the isolation member 13, reducing the risk of wrinkles on the isolation member 13, thereby reducing the possibility of the pores of the isolation member 13 being blocked due to wrinkles.
  • the offset length between the third end 142a and the first end 141a along the winding direction C is greater than zero and less than or equal to 2 mm; and/or the offset length between the fourth end 142b and the second end 141b along the winding direction C is greater than zero and less than or equal to 2 mm.
  • the offset length may be 0.5 mm, 1 mm, 1.5 mm, 1.8 mm, or 2 mm.
  • the offset length between the seventh end 144a and the fifth end 143a along the winding direction C is greater than zero and less than or equal to 2 mm; and/or the offset length between the eighth end 144b and the sixth end 143b along the winding direction C is greater than zero and less than or equal to 2 mm.
  • the offset length may be 0.5 mm, 1 mm, 1.5 mm, 1.8 mm, or 2 mm.
  • the length of the staggered ends of the first protective layer 141 and the second protective layer 142 on the same side of the winding direction C is too large, there is a large staggered distance between the portion of the first protective layer 141 that exceeds the separator 13 and the portion of the second protective layer 142 that exceeds the separator 13, resulting in a large surface exposed glue area of the portion of the first protective layer 141 and the second protective layer 142 that exceeds the separator 13, which is easy to stick to the roller and cause tearing during the winding process.
  • the length of the staggered ends of the first protective layer 141 and the second protective layer 142 on the same side of the winding direction C is controlled to be greater than zero and less than or equal to 2 mm, which can reduce the risk of wrinkles of the separator 13 and the risk of tearing caused by sticking to the roller.
  • the winding structure includes a straight area B connected to the bending area A, and the protective layer 14 extends at least one end in the winding direction C of the winding structure to the junction between the straight area B and the bending area A or extends along the winding direction C beyond the junction to the straight area B.
  • Only one end of the protective layer 14 in the winding direction C of the winding structure extends to the junction between the straight area B and the bending area A, or extends to the straight area B beyond the junction along the winding direction C; or, both ends of the protective layer 14 in the winding direction C of the winding structure extend to the junction between the straight area B and the bending area A, or extend to the straight area B beyond the junction along the winding direction C.
  • the protective layer 14 located at the positive electrode bending portion 111 can cover the positive electrode active material layer 113 in the winding direction C, and the positive electrode active material layer 113 is fully protected; the protective layer 14 located at the negative electrode bending portion 121 can cover the negative electrode active material layer 123 in the winding direction C, and the negative electrode active material layer 123 is fully protected.
  • At least one of the first protection layer 141 located at the first concave surface 11 a and the second protection layer 142 located at the first convex surface 111 b has pores for ions to pass through.
  • Only at least a portion of the first protective layer 141 located at the first concave surface 11a of the positive electrode bend 111 may have pores for ion permeation.
  • only at least a portion of the second protective layer 142 located at the first convex surface 111b of the positive electrode bend 111 may have pores for ion permeation.
  • both at least a portion of the first protective layer 141 located at the first concave surface 11a of the positive electrode bend 111 and at least a portion of the second protective layer 142 located at the first convex surface 111b may have pores for ion permeation.
  • the ions may be active ions in the active material.
  • the active ions when the battery is a lithium ion battery, the active ions are lithium ions; when the battery is a sodium ion battery, the active ions may be sodium ions; when the battery is a magnesium ion battery, the active ions may be magnesium ions; of course, the ions may also be other possible active ions present in the active material.
  • the protective layer has pores for ion permeation, thereby reducing or preventing the loss of battery capacity.
  • the first protective layer 141 located at the first concave surface 11a and the second protective layer 142 located at the first convex surface 111b have pores for ion penetration, which can protect the positive electrode bending portion 111 from breaking and the risk of the respective active materials falling off. It is also possible to reduce the influence of the protective layer attached to the positive electrode bent portion 111 on the release of the positive electrode active material in the positive electrode active material layer 113 at the positive electrode bent portion 111 .
  • the blocking portion for blocking ions on the first protective layer 141 can block the number of lithium ions provided by a part of the positive electrode active material layer, thereby reducing the lithium precipitation phenomenon.
  • the third protection layer 143 located on the second concave surface 121 a and the fourth protection layer 144 located on the second convex surface 121 b both have pores for ion permeation.
  • the number of lithium ions that can be provided by the negative active material layer of the negative electrode bend 121 is less than that of the positive active material layer of the adjacent positive electrode bend 111, in other words, the number of lithium ions that can be provided by the positive active material layer of the positive electrode bend 111 is greater than the number of lithium ions that can be provided by the negative active material layer of the negative electrode bend 121, if the negative active material layer on the negative electrode bend 121 is blocked, it is more likely to cause insufficient lithium insertion sites of the negative active material layer, and more likely to cause lithium precipitation.
  • the third protective layer 143 at the second concave surface 121a of the negative electrode bend 121 and the fourth protective layer 144 at the second convex surface 121b of the negative electrode bend 121 both have pores for ion penetration, so that while protecting the negative electrode bend 121, the lithium precipitation phenomenon can also be reduced.
  • the air permeability of the protective layer having pores for ion permeation is 220 ⁇ 70sec/100cc (sec is in seconds, cc is in cubic centimeters).
  • the air permeability can be measured, for example, according to the standard document GB/T36363-2018, that is, the time required for 100ml of air to pass through the isolation piece with an area of 6.45cm2 under the test temperature, humidity and normal pressure environment and the test instrument applying a pressure of 1.21kPa.
  • the applied pressure of 1.21kPa is a constant pressure, and the area of 6.45cm2 passed is a fixed area.
  • the minimum size range of the pores for ion permeation in the protective layer may be 100 nm to 400 nm.
  • the minimum size range of the pores may be 100 nm, 120 nm, 150 nm, 200 nm, 210 nm, 220 nm, 250 nm, 270 nm, 300 nm, 310 nm, 320 nm, 330 nm, 340 nm, 350 nm, 360 nm, 370 nm, 380 nm, 390 nm, 400 nm.
  • the minimum size of the pores may be measured by scanning electron microscopy.
  • the embodiment of the present disclosure further provides a battery cell 160 , including: a housing 20 and at least one of the electrode assemblies 10 mentioned above, wherein the electrode assembly 10 is accommodated in the housing 20 .
  • the embodiment of the present disclosure further provides a battery 100 , including: a box body 110 and at least one battery cell 160 mentioned above, wherein the battery cell 160 is accommodated in the box body 110 .
  • the embodiment of the present disclosure further provides an electric device, which includes at least one of the above-mentioned battery cells 160 or batteries 100 for providing electric energy.
  • the present disclosure also provides a method for preparing an electrode assembly, as shown in FIG15 , comprising:
  • Step S1 providing a positive electrode sheet, a negative electrode sheet and a separator
  • Step S2 attaching a protective layer to the positive electrode sheet and/or the negative electrode sheet;
  • Step S3 stacking and winding the positive electrode sheets, the negative electrode sheets and the separator to form a winding structure, wherein in the winding structure, an separator is sandwiched between the positive electrode sheets and the negative electrode sheets, the winding structure includes a bending area, the positive electrode sheets include at least one positive bending portion located in the bending area, the negative electrode sheets include at least one negative bending portion located in the bending area, along the winding axis direction of the winding structure, both ends of the separator extend beyond the positive bending portion and the negative bending portion, a protective layer is adhered to the surface of the positive bending portion and/or the surface of the negative bending portion, and along the winding axis direction of the winding structure, at least one end of the protective layer extends beyond the separator.
  • the protective layer may be attached to the positive electrode sheet and/or the negative electrode sheet first, and then the winding process may be performed.
  • the attachment of the protective layer to the positive electrode sheet and/or the negative electrode sheet may be performed during the electrode sheet die cutting process, and then the winding process may be performed.
  • the attachment of the protective layer to the positive electrode sheet and/or the negative electrode sheet may also be performed while winding, for example, a pasting module is integrated in the winding device, and the protective layer is pasted to the positive electrode sheet and/or the negative electrode sheet during the winding process of the winding device.
  • an electrode assembly and a preparation method thereof, a battery cell, a battery, an electrical device, and an energy storage device with reduced thermal runaway risk are provided.
  • a protective layer By attaching a protective layer to the positive electrode bend and the negative electrode bend, the risk of fracture and active material shedding when the positive electrode bend and the negative electrode bend are bent can be reduced, thereby reducing the risk of thermal runaway of the electrode assembly, the battery cell, and even the battery as a whole; the protective layer exceeds the isolation piece, so that the adhesive tape can completely cover the positive and negative electrode sheets and reliably protect them, and the attachment position of the protective layer can be visually observed through the exposed part during the battery manufacturing process, and the accuracy of the attachment position can be confirmed in time.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Secondary Cells (AREA)

Abstract

本公开公开了一种电极组件及其制备方法、电池单体、电池、用电装置、储能装置，电极组件包括：卷绕结构，卷绕结构由包括正极极片和负极极片的层叠体卷绕而成，在正极极片与负极极片之间夹置有隔离件，卷绕结构包括弯折区，正极极片包括位于弯折区的至少一个正极弯折部，负极极片包括位于弯折区的至少一个负极弯折部，沿着卷绕结构的卷绕轴线方向，隔离件的两端超出正极弯折部和负极弯折部；以及保护层，附接于正极弯折部的表面和/或负极弯折部的表面，沿着卷绕结构的卷绕轴线方向，保护层的至少一端超出隔离件。

Description

电极组件及其制备方法、电池单体、电池、用电装置、储能装置 技术领域
本公开涉及电池技术领域，尤其涉及电极组件及其制备方法、电池单体、电池、用电装置、储能装置。
背景技术
新能源电池在生活和产业中的应用越来越广泛，例如，搭载电池的新能源汽车已经被广泛使用，另外，电池还被越来越多地应用于储能领域等。
在搭载电池的新能源汽车中，电池可以用于全部或部分地提供动力。在储能领域中，电池可以安装于储能箱体或是直接安装于用户侧。在电池技术的发展中，除了提高电池单体的性能外，电池单体热失控问题也是一个不可忽视的问题。因此，如何降低电池单体的热失控风险，是电池技术中一个亟待解决的技术问题。
发明内容
为解决上述技术问题，本公开提供一种电极组件及其制备方法、电池单体、电池、用电装置、储能装置，能够降低电池的热失控风险。
本公开通过如下技术方案实现。
本公开的第一方面提供一种电极组件，包括：卷绕结构，所述卷绕结构由包括正极极片和负极极片的层叠体卷绕而成，在所述正极极片与所述负极极片之间夹置有隔离件，所述卷绕结构包括弯折区，所述正极极片包括位于所述弯折区的至少一个正极弯折部，所述负极极片包括位于所述弯折区的至少一个负极弯折部，沿着所述卷绕结构的卷绕轴线方向，所述隔离件的两端超出所述正极弯折部和所述负极弯折部；以及保护层，附接于所述正极弯折部的表面和/或所述负极弯折部的表面，沿着所述卷绕结构的卷绕轴线方向，所述保护层的至少一端超出所述隔离件。
通过在正极弯折部和负极弯折部附接保护层，能够降低正极弯折部和负极弯折部折弯时断裂和活性物质脱落的风险，从而降低电极组件、电池单体乃至电池整体的热失控风险；保护层超出隔离件，能够使胶纸完全覆盖正、负极极片而对其进行可靠的保护，而且能够在电池制造过程中通过露出的部分目测到保护层的附接位置，及时确认附接位置的准确性。
在一些实施例中，所述保护层以粘贴或静电吸附的方式附接于所述正极弯折部的表面 和/或所述负极弯折部的表面。粘贴的方式附接更牢固；静电吸附的方式降低附接时损伤极片的可能性。
在一些实施例中，沿着所述卷绕结构的层叠方向，各所述正极弯折部包括位于相反两侧的第一凹面和第一凸面，所述保护层包括分别附接于所述第一凹面和所述第一凸面的第一保护层和第二保护层。通过在正极弯折部的正反两侧的第一凹面和第一凸面均附接保护层，进一步降低正极弯折部断裂的风险，并且能够降低正极弯折部两个表面的正极活性物质层脱落的风险，降低短路、热失控等风险。
在一些实施例中，沿着所述卷绕结构的层叠方向，各所述负极弯折部包括位于相反两侧的第二凹面和第二凸面，所述保护层包括分别附接于所述第二凹面和所述第二凸面的第三保护层和第四保护层。
通过在负极弯折部的正反两侧的第二凹面和第二凸面均附接保护层，进一步降低负极弯折部断裂引起短路、热失控的风险，并且能够降低负极弯折部两个表面的负极活性物质层脱落的风险，减少对电池容量、循环寿命的影响。
在一些实施例中，所述正极极片包括正极集流体以及设置于所述正极集流体的表面的正极活性物质层，所述保护层覆盖所述正极极片中的所述正极弯折部处的所述正极活性物质层；和/或，所述负极极片包括负极集流体以及设置于所述负极集流体的表面的负极活性物质层，所述保护层覆盖所述负极极片中的所述负极弯折部处的所述负极活性物质层。
通过保护层覆盖正极弯折部处的正极活性物质层和/或负极弯折部处的负极活性物质层，能够全面保护正极活性物质层和负极活性物质层，降低正极活性物质层和负极活性物质层脱落风险。
在一些实施例中，在所述正极弯折部，沿着所述卷绕轴线方向，位于所述正极弯折部的所述保护层的第一边缘超出所述正极活性物质层但不超出所述隔离件，位于所述正极弯折部的所述保护层的第二边缘超出所述隔离件，其中，所述第一边缘位于所述保护层沿着所述卷绕轴线方向的一端，所述第二边缘位于所述保护层沿着所述卷绕轴线方向的另一端；和/或，在所述负极弯折部，沿着所述卷绕轴线方向，位于所述负极弯折部的所述保护层的第三边缘超出所述负极活性物质层但不超出所述隔离件，位于所述负极弯折部的所述保护层的第四边缘超出所述隔离件，其中，所述第三边缘位于所述保护层的沿着所述卷绕轴线方向的一端，所述第四边缘位于所述保护层的沿着所述卷绕轴线方向的另一端。
由于保护层覆盖正、负极活性物质层的同时，仅有一个边缘超出隔离件，即可目测到保护层位于正极弯折部的粘贴位置，相较于两个边缘均超出隔离件的情况，能够降低隔离件粘辊导致自身撕裂的风险。
在一些实施例中，在所述正极集流体，在所述卷绕轴线方向的一侧设有正极极耳，所述保护层的所述第一边缘沿着所述卷绕轴线方向与所述正极极耳位于同侧；和/或，在所述负极集流体，在所述卷绕轴线方向的一侧设有负极极耳，所述保护层的所述第三边缘沿着所述卷绕轴线方向与所述负极极耳位于同侧。通过位于极耳同侧的保护层边缘不超出隔离件，能够避免极耳侧方的检测设备误报的风险。
在一些实施例中，沿所述卷绕轴线方向，所述保护层超出所述正极弯折部的长度为4mm～6mm；和/或，沿所述卷绕轴线方向，所述保护层超出所述负极弯折部的长度为4mm～6mm。
通过使保护层超出正、负极弯折部规定的长度，能够使得保护层伸出于外部的部分容易目测，从而能够容易地确认保护层的位置，也便于确定保护层在正、负极片上的附接位置。
在一些实施例中，沿所述卷绕轴线方向，所述保护层超出所述隔离件的长度为1mm～4mm。
通过将护层超出隔离件的长度控制为1mm～4mm之间，既能方便目测保护层的粘贴位置，也能降低保护层粘辊导致撕裂的风险。
在一些实施例中，沿着所述卷绕轴方向，在至少一端，所述第一保护层和所述第二保护层中的一者超出另外一者。
在一些实施例中，所述第一保护层包括沿着所述卷绕结构的卷绕方向位于两端的第一端和第二端，所述第二保护层包括沿着所述卷绕方向位于两端的第三端和第四端，所述第三端与所述第一端沿着所述卷绕方向的同一侧且沿着所述卷绕方向相互错开，和/或，所述第四端与所述第二端在所述卷绕方向的同一侧且沿着所述卷绕方向相互错开。
通过第一保护层和第二保护层同侧的两端相互错开，相较于非错开，能够降低各保护层层叠后的端部的台阶高度，因此，在卷绕结构挤压成型过程中，能够对隔离件的挤压形成缓冲，降低隔离件褶皱风险，从而减少因褶皱引起的隔离件的孔隙被阻挡的可能性。
在一些实施例中，所述第三端与所述第一端沿着所述卷绕方向的错开长度大于零且小于等于2mm；和/或，所述第四端与所述第二端沿着所述卷绕方向的错开长度大于零且小于等于2mm。
通过将第一保护层和第二保护层沿着卷绕方向同侧的两端错开的长度控制在大于零且小于等于2mm范围，既可以降低隔离件褶皱风险，又可以降低粘辊导致撕裂风险。
在一些实施例中，所述第三保护层包括在所述卷绕结构的卷绕方向的第五端和第六端，所述第四保护层包括在所述卷绕方向的第七端和第八端，所述第七端与所述第五端在所述 卷绕方向的同一侧且沿着所述卷绕方向相互错开，和/或，所述第八端与所述第六端在所述卷绕方向的同一侧且沿着所述卷绕方向相互错开。
通过第三保护层和第四保护层同侧的两端相互错开，相较于非错开，能够降低各保护层层叠后的端部的台阶高度，因此，在卷绕结构挤压成型过程中，能够对隔离件的挤压形成缓冲，降低隔离件褶皱风险，从而减少因褶皱引起的隔离件的孔隙被阻挡的可能性。
在一些实施例中，所述第七端与所述第五端沿着所述卷绕方向的错开长度大于零且小于等于2mm；和/或，所述第八端与所述第六端沿着所述卷绕方向的错开长度大于零且小于等于2mm。
通过将第三保护层和第四保护层沿着卷绕方向同侧的两端错开的长度控制在大于零且小于等于2mm范围，既可以降低隔离件褶皱风险，又可以降低粘辊导致撕裂风险。
在一些实施例中，所述卷绕结构包括与所述弯折区连接的平直区，所述保护层在所述卷绕结构的卷绕方向上的至少一端延伸至所述平直区与所述弯折区之间的交界处或者沿着所述卷绕方向超过所述交界处延伸至所述平直区。
由此，位于正极弯折部处的保护层能够在卷绕方向上覆盖正极活性物质层，正极活性物质层得到全面保护；位于负极弯折部处的保护层能够在卷绕方向上覆盖负极活性物质层，负极活性物质层得到全面保护。
在一些实施例中，所述正极极片包括位于所述弯折区的沿着所述卷绕结构的层叠方向排列的多个所述正极弯折部，所述保护层至少附接于沿着所述层叠方向位于最内侧的所述正极弯折部；和/或，所述负极极片包括位于所述弯折区的沿着所述卷绕结构的层叠方向排列的多个所述负极弯折部，所述保护层至少附接于沿着所述层叠方向位于最内侧的所述负极弯折部。
由于在层叠方向的最内侧的正极弯折部和负极弯折部受到的拉伸力更大，更容易导致断裂或者活性物质脱落。因此，保护层至少附接于最内侧的正极弯折部和负极弯折部上，能够对最内侧正极弯折部和负极弯折部形成保护，有利于降低电池整体的短路、热失控风险。
在一些实施例中，所述保护层的材质为聚对苯二甲酸乙二酯、聚丙烯、聚乙烯、聚酰亚胺或无纺布。
在一些实施例中，第一凸面处的所述第二保护层中的至少一者具有用于供离子透过的孔隙；或者，位于所述第一凹面处的所述第一保护层和位于所述第一凸面处的所述第二保护层均包括用于阻挡离子的阻挡部。
位于第一凹面处的第一保护层和位于第一凸面处的第二保护层具有用于供离子透过的 孔隙，能够保护正极弯折部断裂和各自的活性物质脱落的风险，同时还能降低因保护层附接到正极弯折部对正极弯折部处的正极活性物质层中正极活性物质脱出的影响。通过第一保护层上的用于阻挡离子的阻挡部，能够阻挡一部分正极活性物质层提供的锂离子数量，因此能够降低析锂现象。
在一些实施例中，位于所述第二凹面处的所述第三保护层和位于所述第二凸面处的所述第四保护层均具有用于供离子透过的孔隙。
由于负极弯折部的第二凹面处的第三保护层和第二凸面处的第四保护层均具有用于供离子透过的孔隙，因此在能够保护负极弯折部的同时，还能降低析锂现象。
在一些实施例中，具有用于供离子透过的孔隙的所述保护层的透气度为220±70sec/100cc。
在一些实施例中，所述孔隙的孔隙为100nm～400nm。
本公开的第二方面提供一种电池单体，包括：壳体和至少一个本公开第一方面提供的电极组件，所述电极组件容纳于所述壳体内。
本公开的第三方面提供一种电池，包括：箱体和至少一个本公开第二方面提供的电池单体，所述电池单体收容于所述箱体内。
本公开的第四方面提供一种用电装置，所述用电装置包括用于提供电能的至少一个本公开第二方面提供的电池单体或者本公开第三方面提供的电池。
本公开的第五方面提供一种储能装置，包括本公开第三方面提供的电池，所述电池能够储存电能且能够提供电能。
本公开的第六方面提供一种电极组件制备方法，包括：提供正极极片、负极极片和隔离件；针对正极极片和/或负极极片附接保护层；对所述正极极片、所述负极极片及所述隔离件进行层叠卷绕形成卷绕结构，其中，在所述卷绕结构中，在所述正极极片与所述负极极片之间夹置有隔离件，所述卷绕结构包括弯折区，所述正极极片包括位于所述弯折区的至少一个正极弯折部，所述负极极片包括位于所述弯折区的至少一个负极弯折部，沿着所述卷绕结构的卷绕轴线方向，所述隔离件的两端超出所述正极弯折部和所述负极弯折部，在所述正极弯折部的表面和/或所述负极弯折部的表面粘贴有所述保护层，沿着所述卷绕结构的卷绕轴线方向，所述保护层的至少一端超出所述隔离件。
附图说明
通过阅读对下文优选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。附图仅用于示出优选实施方式的目的，而并不认为是对本公开的 限制。而且在全部附图中，用相同的附图标记表示相同的部件。在附图中：
图1为本公开一些实施例提供的车辆的结构示意图；
图2为本公开的一些实施例提供的电池的立体分解示意图；
图3为本公开的一些实施例提供的电池模块的立体示意图；
图4为本公开的一些实施例提供的电池单体的立体分解示意图；
图5为本公开的一些实施例提供的电极组件的立体示意图；
图6为本公开一些实施例提供的电极组件的剖面示意图；
图7为图6中部分放大示意图；
图8为图7中z-z位置的剖面示意图；
图9为本公开一些实施例提供的电极组件的正极极片沿卷绕方向展开的结构示意图；
图10为本公开一些实施例提供的电极组件的负极极片沿卷绕方向展开的结构示意图；
图11为本公开另一些实施例提供的电极组件的剖面示意图；
图12为图11中部分放大示意图；
图13为本公开另一些实施例提供的电极组件的正极极片沿卷绕方向展开的结构示意图；
图14为本公开另一些实施例提供的电极组件的负极极片沿卷绕方向展开的结构示意图；
图15为本公开一些实施例提供的电极组件制备方法的流程图。
附图标记说明
1000车辆；
100电池，200控制器，300马达；
110箱体，120第一箱体部，130第二箱体部，140电池模块，150容纳空间，160电池单体；
10电极组件，20外壳，21壳体，22端盖，30正极电极端子，40负极电极端子，50泄压机构；
11正极极片，111正极弯折部，112正极集流体，112a正极集流部，112b正极凸部(正极极耳)，113正极活性物质层，111a第一凹面，111b第一凸面；
12负极极片，121负极弯折部，122负极集流体，122a负极集流部，122b负极凸部(正极极耳)，123负极活性物质层，124绝缘层，121a第二凹面，121b第二凸面；
13隔离件；
14保护层，141第一保护层，142第二保护层，143第三保护层，144第四保护层，141a第一端，141b第二端，142a第三端，142b第四端，143a第五端，143b第六端，144a第七端，144b第八端，14a第一边缘，14b第二边缘，14c第三边缘，14d第四边缘；
A弯折区，B平直区，C卷绕方向，K卷绕轴线方向，E层叠方向，长度d1，长度d2。
具体实施方式
下面将结合附图对本公开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公开的技术方案，因此只作为示例，而不能以此来限制本公开的保护范围。
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公开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，不是旨在于限制本公开；本公开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。
在本公开实施例的描述中，技术术语“第一”“第二”“第三”“第四”“第五”“第六”“第七”“第八”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。在本公开实施例的描述中，“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公开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。
在本公开实施例的描述中，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“或”的关系。
在本公开实施例的描述中，技术术语“长度”“宽度”“厚度”“内”“外”“层叠方向”“卷绕轴线方向”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公开实施例和简化描述，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、操作或使用，因此不能理解为对本公开实施例的限制。
在本公开实施例的描述中，除非另有明确的规定和限定，技术术语“安装”“相连”“连接”“固定”等术语应作广义理解，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公开实施例中的具体含义。
在本公开实施例的描述中，除非另有明确的规定和限定，技术术语“接触”应作广义理解，可以是直接接触，也可以是隔着中间媒介层的接触，可以是相接触的两者之间基本 上没有相互作用力的接触，也可以是相接触的两者之间具有相互作用力的接触。
下面，对本公开进行详细说明。
目前，新能源电池在生活和产业中的应用越来越广泛。新能源电池不仅被应用于水力、火力、风力和太阳能电站等储能电源系统，而且还被广泛应用于电动自行车、电动摩托车、电动汽车等电动交通工具，以及航空航天等多个领域。随着新能源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。
在卷绕式裸电芯的制备过程中，卷绕的电极组件需要挤压整形，从而消除隔离件褶皱和内部空气，降低短路风险，同时提升表面平整度，便于入壳。电极组件在受到挤压时，因卷绕而弯折处的极片上的活性物质有可能脱落，弯折位置甚至会出现极片断裂的风险。极片上的活性物质脱落，称之为掉粉现象。极片断裂或极片上的活性物质脱落均会导致电池热失控问题。极片断裂容易刺破隔离件，有可能造成相邻的正极极片和负极极片短路，进而发生热失控问题，导致电池爆炸起火。极片上的活性物质的脱落，不仅影响电池容量，也可能导致析锂现象。
锂离子电池或电池单体在充电过程中，当负极极片的负极活性物质层的嵌锂位少于其相邻的正极极片的正极活性物质层能够提供的锂离子数量时，容易发生析锂现象。析锂不仅使锂离子电池性能下降，循环寿命大幅缩短，还限制了锂离子电池的快充容量。除此之外，锂离子电池发生析锂时，析出来的锂金属非常活泼，在较低的温度下便可以与电解液发生反应，造成电池自产热起始温度降低和自产热速率增大，存在热失控风险。再者，析锂严重时，脱出的锂离子可以在负极极片表面形成锂枝晶，而锂枝晶容易刺破隔离件，造成相邻的正极极片和负极极片短路，存在引发热失控的风险。
卷绕式的电极组件(裸电芯)在其弯折区容易出现析锂现象，造成该析锂现象的原因主要是因为位于弯折区的正极极片和负极极片需要进行折弯，处于正极极片内侧的负极极片容易出现嵌锂空间不足的情况，可能导致该负极极片的负极活性物质层的嵌锂位少于其相邻的正极极片的正极活性物质层能够提供的锂离子数量，从而引发析锂现象。此外，电极组件受到挤压变形时，在弯折区的正极极片和负极极片的表面会受到较大的拉伸力，尤其是最内层的正极极片和最内层的负极极片受到的拉伸力更大，容易导致正极极片和负极极片上各自的活性物质层脱落，影响电池容量，甚至可能出现弯折区的正极极片和负极极片断裂风险，导致电池热失控风险。
通过在弯折区的正极极片和负极极片上附接保护层(例如粘胶)，可以降低极片开裂和活性物质脱落的风险。但是，发明人发现，即使在弯折区的正极极片和负极极片上粘胶还可能存在电池安全性问题，对此，发明人尝试分析原因，认为可能的原因是：由于在贴完 胶之后进行极片的卷绕，胶被包裹于卷绕结构中，无法确定贴胶的位置是否恰好在弯折区。若贴胶的位置不在弯折区，那么弯折区的掉粉、断裂风险等则依然存在，因此，贴胶位置无法准确判断的情况下，依然存在因掉粉、极片断裂引起短路、热失控的风险。
鉴于此，本公开实施例提供了一种电极组件，包括：卷绕结构，卷绕结构由包括正极极片和负极极片的层叠体卷绕而成，在正极极片与负极极片之间夹置有隔离件，卷绕结构包括弯折区，正极极片包括位于弯折区的至少一个正极弯折部，负极极片包括位于弯折区的至少一个负极弯折部，沿着卷绕结构的卷绕轴线方向，隔离件的两端超出正极弯折部和负极弯折部；以及保护层，附接于正极弯折部的表面和/或负极弯折部的表面，沿着卷绕结构的卷绕轴线方向，保护层的至少一端超出隔离件。
通过保护层附接在正极弯折部的表面和/或负极弯折部的表面，能够降低弯折区的正极极片和/或负极极片断裂和活性物质脱落的风险，从而降低电极组件、电池单体乃至电池整体的热失控风险；并且，通过保护层超出隔离件，能够使保护层完全覆盖正、负极极片而对其进行可靠的保护，而且保护层的粘贴位置在电池制造过程中(例如卷绕过程中)可被目测到，从而能够对粘贴位置作出准确判断。
本公开实施例的电极组件适用于电池单体、电池。
本公开实施例的电池可以但不限用于储能电源系统、车辆、船舶或飞行器等用电装置中。
本公开实施例的电池还可以多个成组而作为电池包使用。电池包同样可以但不限用于储能电源系统、车辆、船舶或飞行器等用电装置中。
本公开实施例提供了一种包括用于提供电能的上述电池或电池包的用电装置，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。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。
本公开实施例还提供了一种包括上述电池或电池包的储能装置，储能装置可以为但不限于储能电箱、储能集装箱等。
在以下实施例中，为了方便说明，以本公开一实施例的用电装置为车辆1000为例进行说明。下面结合附图进行说明。
图1为本公开的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。如图1所示，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。
在本公开一些实施例中，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。
图2为本公开的一些实施例提供的电池的立体分解示意图。如图2所示，电池100包括箱体110和电池单体(图2未示出)，电池单体容纳于箱体110内。
箱体110用于容纳电池单体，箱体110可以是多种结构。在一些实施例中，箱体110可以包括第一箱体部120和第二箱体部130，第一箱体部120与第二箱体部130相互盖合，第一箱体部120和第二箱体部130共同限定出用于容纳电池单体的容纳空间150。第二箱体部130可以是一端开口的空心结构，第一箱体部120为板状结构，第一箱体部120盖合于第二箱体部130的开口侧，以形成具有容纳空间150的箱体110；第一箱体部120和第二箱体部130也均可以是一侧开口的空心结构，第一箱体部120的开口侧盖合于第二箱体部130的开口侧，以形成具有容纳空间150的箱体110。当然，第一箱体部120和第二箱体部130可以是多种形状，例如，圆柱体、长方体等。
为提高第一箱体部120与第二箱体部130连接后的密封性，第一箱体部120与第二箱体部130之间也可以设置密封件，例如，密封胶、密封圈等。
假设第一箱体部120盖合于第二箱体部130的顶部，第一箱体部120亦可称之为上箱盖，第二箱体部130亦可称之为下箱体。
在电池100中，电池单体可以是一个，也可以是多个。若电池单体为多个，多个电池单体之间可串联或并联或混联，混联是指多个电池单体中既有串联又有并联。多个电池单体之间可直接串联或并联或混联在一起，再将多个电池单体构成的整体容纳于箱体110内；当然，也可以是多个电池单体先串联或并联或混联组成电池模块140，多个电池模块140再串联或并联或混联形成一个整体，并容纳于箱体110内。
图3为本公开的一些实施例提供的电池模块的立体示意图。如图3所示，在一些实施例中，电池单体160为多个，多个电池单体160先串联或并联或混联组成电池模块140。多个电池模块140再串联或并联或混联形成一个整体，并容纳于箱体内。
电池模块140中的多个电池单体160之间可通过汇流部件实现电连接，以实现电池模块140中的多个电池单体160的并联或串联或混联。
图4为本公开的一些实施例提供的电池单体的立体分解示意图；图5为本公开的一些实施例提供的电极组件的立体示意图。如图4和图5所示，本公开实施例提供的电池单体160 包括电极组件10和外壳20，电极组件10容纳于外壳20内。
电池单体160可以为二次电池，二次电池是指在电池单体放电后可通过充电的方式使活性材料激活而继续使用的电池单体。
电池单体160可以为锂离子电池、钠离子电池、钠锂离子电池、锂金属电池、钠金属电池、锂硫电池、镁离子电池、镍氢电池、镍镉电池、铅蓄电池等，本公开实施例对此并不限定。
电极组件10包括正极极片、负极极片以及隔离件。在电池单体160充放电过程中，活性离子(例如锂离子)在正极极片和负极极片之间往返嵌入和脱出。隔离件设置在正极极片和负极极片之间，可以起到防止正极极片和负极极片短路的作用，同时可以使活性离子通过。
在一些实施例中，电极组件设有极耳，极耳可以将电流从电极组件导出。极耳包括正极极耳和负极极耳。
在一些实施例中，外壳20还可用于容纳电解质，例如电解液。外壳20可以是多种结构形式。外壳可以为钢壳、铝壳、塑料壳(如聚丙烯)、复合金属壳(如铜铝复合外壳)或铝塑膜等。
在一些实施例中，外壳20可以包括壳体21和端盖22，壳体21为一侧开口的空心结构，端盖22盖合于壳体21的开口处并形成密封连接，以形成用于容纳电极组件10和电解质的密封空间。
壳体21可以是多种形状，例如，正方体、长方体等。壳体21的形状可根据电极组件10的具体形状来确定。端盖22可以是多种结构，例如，端盖22为板状结构、一端开口的空心结构等。示例性的，在图4中，壳体21为长方体结构，端盖22为板状结构，端盖22盖合于壳体21顶部的开口处。
在一些实施例中，电池单体160还可以包括正极电极端子30、负极电极端子40和泄压机构50，正极电极端子30、负极电极端子40和泄压机构50均安装于端盖22上。正极电极端子30和负极电极端子40均用于与电极组件10电连接，以输出电极组件10所产生的电能。泄压机构50用于在电池单体160的内部压力或温度达到预定值时泄放电池单体160内部的压力。
示例性的，泄压机构50位于正极电极端子30和负极电极端子40之间，泄压机构50可以是诸如防爆阀、防爆片、气阀、泄压阀或安全阀等部件。
在另一些实施例中，外壳20也可以是其他结构，例如，外壳20包括壳体21和两个端盖22，壳体21为相对的两侧开口的空心结构，一个端盖22对应盖合于壳体21的一个开口 处并形成密封连接，以形成用于容纳电极组件10和电解质的密封空间。在这种结构中，正极电极端子30和负极电极端子40可安装在同一个端盖22上，也可以安装在不同的端盖22上；可以是一个端盖22上安装有泄压机构50，也可以是两个端盖22上均安装有泄压机构50。
需要说明的是，在电池单体160中，容纳于外壳20内的电极组件10可以是一个，也可以是多个。示例性的，在图4中，电极组件10为两个。
图5为本公开一些实施例提供的电极组件的立体示意图。图6为本公开一些实施例提供的电极组件的剖面示意图。图7为图6中部分放大示意图。图8为图7中z-z位置的剖面示意图。图9为本公开一些实施例提供的电极组件的正极极片沿卷绕方向展开的结构示意图。图10为本公开一些实施例提供的电极组件的负极极片沿卷绕方向展开的结构示意图。
如图5至图10所示，本公开实施例的电极组件10，包括卷绕结构和保护层。卷绕结构由包括正极极片11和负极极片12的层叠体卷绕而成，在正极极片11与负极极片12之间夹置有隔离件13，卷绕结构包括弯折区A，正极极片11包括位于弯折区A的至少一个正极弯折部111，负极极片12包括位于弯折区A的至少一个负极弯折部121，沿着卷绕结构的卷绕轴线K方向，隔离件13的两端超出正极弯折部111和负极弯折部121；保护层14附接于正极弯折部111的表面和/或负极弯折部112的表面，沿着卷绕结构的卷绕轴线K方向，保护层14的至少一端超出隔离件13。
如图9所示，正极极片11包括正极集流体112和正极活性物质层113，正极活性物质层涂113涂覆于正极集流体112的表面；正极集流体112包括正极集流部112a和凸出于正极集流部112a的正极凸部112b，正极集流部112a涂覆有正极活性物质层113，正极凸部112b的至少部分未涂覆正极活性物质层113，正极凸部112b作为正极极耳。以下说明中，正极凸部112b可以为正极极耳112b。以锂离子电池为例，正极集流体112的材料可以为铝(铝箔)，正极活性物质层113包括正极活性物质，正极活性物质可以为钴酸锂、磷酸铁锂、三元锂或锰酸锂等。
如图10所示，负极极片12包括负极集流体122和负极活性物质层123，负极活性物质层123涂覆于负极集流体122的表面；负极集流体122包括负极集流部122a和凸出于负极集流部122a的负极凸部122b，负极集流部122a涂覆有负极活性物质层123，负极凸部122b的至少部分未涂覆负极活性物质层123，负极凸部122b作为负极极耳。以下说明中，负极凸部122b可以为负极极耳122b。以锂离子电池为例，负极集流体122的材料可以为铜(铜箔)，负极活性物质层123包括负极活性物质，负极活性物质可以为碳(例如石墨碳)或硅等。
为了保证通过大电流而不发生熔断，正极极耳112b的数量为多个且层叠在一起，负极极耳122b的数量为多个且层叠在一起。
如图5-图8所示，正极极片11和负极极片12相互层叠形成层叠体。层叠体绕着卷绕轴线K卷绕两圈以上形成卷绕结构。卷绕轴线K的延伸方向与卷绕结构的卷绕方向C以及层叠方向E(见图8)垂直。
在每相邻的正极极片11和负极极片12之间夹置有隔离件13，隔离件13用于将正极极片11和负极极片12隔离，以降低正极极片11与负极极片12之间出现短路的风险。示例性地，隔离件13的材质可以为PP(polypropylene，聚丙烯)或PE(polyethylene，聚乙烯)等。
正极极片11、负极极片12和隔离件13均可以为带状结构。本公开实施例可以先将正极极片11、隔离件13、负极极片12、隔离件13依次层叠，然后再绕着卷绕轴线K由内向外卷绕两圈以上形成卷绕结构。图6中，卷绕结构以顺时针方向卷绕的。当然，卷绕方向也可以是逆时针方向。
卷绕结构包括弯折区A，弯折区A是正极极片11和负极极片12上的具有弯折结构所在的区域，是弯折区的一个示例。在弯折区A，正极弯折部111与负极弯折部121沿着卷绕结构的层叠方向E交替分布，即在弯折区A，以正极弯折部111、负极弯折部121、正极弯折部111、负极弯折部121……的顺序由内侧向外侧依次排布，其中，内侧相比外侧更靠近卷绕轴线K，层叠方向E为卷绕结构的层厚方向。示例地，最内侧的正极弯折部111位于最内侧的负极弯折部121的外侧。示例性地，正极弯折部111和负极弯折部121的形状可以为大体圆弧形。
如图8至图10所示，沿着卷绕结构的卷绕轴线方向K，隔离件13的两端超出正极弯折部111和负极弯折部121。即，沿着卷绕轴线方向K，隔离件13的两端分别超出正极弯折部111的两端，并且，沿着卷绕轴线方向K，隔离件13的两端分别超出负极弯折部121的两端。换言之，沿着卷绕轴线K方向，正极弯折部111的边缘和负极弯折部121的边缘均不超出隔离件13的端部且具有一定的缩进量。由此，隔离件13能够完全覆盖正极弯折部111和负极弯折部121，有效降低正极极片11与负极极片12之间出现短路的风险。
保护层14附接于正极弯折部111的表面和/或负极弯折部112的表面，可以是，如图6所示，在正极弯折部111和负极弯折部121中的正极弯折部111的表面附接有保护层14；或者，在正极弯折部111和负极弯折部121中的负极弯折部121的表面附接有保护层14；或者，如图11所示，正极弯折部111的表面和负极弯折部121的表面均附接有保护层14。正极弯折部111的表面可以是正极极片11中的正极弯折部111处的正极活性物质层113的表 面。负极弯折部121的表面可以是负极极片12中的负极弯折部121处的负极活性物质层123的表面。
一示例在一些实施例中，保护层14以粘贴或静电吸附的方式附接于正极弯折部111的表面和/或负极弯折部121的表面。其中，保护层14以粘贴的方式附接于正极弯折部111的表面和/或负极弯折部121的表面，可以是，保护层14自身具有粘接层，从而通过该粘接层粘贴在正极弯折部111的表面和/或负极弯折部121的表面。或者，保护层14通过粘性体粘贴在正极弯折部111的表面和/或负极弯折部121的表面，粘性体可以是胶体或者涂覆于正极弯折部111的表面和/或负极弯折部121的表面的胶层。
沿着卷绕结构的卷绕轴线方向K，保护层14的至少一端超出隔离件13，可以是，保护层14的一端超出隔离件13，并且，保护层14的另一端既可以超出隔离件13也可以不超出隔离件13。
保护层14超出隔离件13可以是，沿着卷绕结构的卷绕轴线K方向，保护层14的端部伸出隔离件13的位于保护层14的该端部同侧的边缘。保护层14不超出隔离件13可以是，沿着卷绕结构的卷绕轴线K方向，保护层14的端部缩进于隔离件13的位于保护层14的该端部同侧的边缘，至于缩进的位置，可以位于极片与隔离件13的同侧边缘之间，也可以基本上与极片的边缘齐平。
正极弯折部111和负极弯折部121在折弯过程中产生应力集中并可能引发断裂和各自表面的活性物质脱落的风险，进而存在电池的热失控风险。本公开实施例通过在正极弯折部111和负极弯折部121附接保护层14，能够降低正极弯折部111和负极弯折部121折弯时断裂和活性物质脱落的风险，从而降低电极组件、电池单体乃至电池整体的热失控风险。保护层14超出隔离件13，能够使保护层完全覆盖正、负极极片而对其进行可靠的保护，而且能够在电池制造过程中(例如卷绕过程中)目测到保护层14的附接位置，及时确认附接位置的准确性。
在一些实施例中，保护层14的材质可以为聚对苯二甲酸乙二酯、聚丙烯、聚乙烯、聚酰亚胺或无纺布。在一些实施例中，如图9所示，在正极弯折部111，沿着卷绕轴线K方向，位于正极弯折部111的保护层14的第一边缘14a超出正极活性物质层113但不超出隔离件13，位于正极弯折部111的保护层14的第二边缘14b超出隔离件13，其中，第一边缘14a位于保护层14沿着卷绕轴线方向K的一端，第二边缘14b位于保护层14沿着卷绕轴线方向K的另一端。
位于正极弯折部111的保护层14的第一边缘14a超出正极活性物质层113但不超出隔离件13，可以是，沿着卷绕轴线方向K，第一边缘14a位于同侧的正极活性物质层113边缘 和隔离件13边缘之间。示例地，如图13，正极集流部112a仅部分区域涂覆有正极活性物质层113，正极集流部112a未涂覆正极活性物质层112a的区域涂覆有绝缘层114，绝缘层114位于正极活性物质层113的靠近正极凸部112b(正极极耳)的一侧，且位于同侧的正极活性物质层113边缘和隔离件13边缘之间，第一边缘14a可以位于绝缘层114中。
在保护层14通过自身粘接层粘贴在正极弯折部111的表面时，保护层14超出隔离件13的表面具有粘性，在卷绕工序中，存在粘辊的可能，导致保护层14撕裂风险。
本公开实施例，通过沿着卷绕轴线方向K，位于正极弯折部111的保护层14的第一边缘14a超出正极活性物质层113但不超出隔离件13，位于正极弯折部111的保护层14的第二边缘14b超出隔离件13，由此，保护层14覆盖正极活性物质层113的同时，仅有一个边缘超出隔离件13，即可目测到保护层14位于正极弯折部111的粘贴位置，相较于两个边缘均超出隔离件13，能够降低隔离件13粘辊导致自身撕裂的风险。
在一些实施例中，如图10所示，在负极弯折部121，沿着卷绕轴线方向k，位于负极弯折部121的保护层14的第三边缘14c超出负极活性物质层123但不超出隔离件13，位于负极弯折部的保护层14的第四边缘14d超出隔离件，其中，第三边缘14c位于保护层14的沿着卷绕轴线方向k的一端，第四边缘14d位于保护层14的沿着卷绕轴线方向K的另一端。
位于负极弯折部121的保护层14的第三边缘14c超出负极活性物质层123但不超出隔离件13，可以是，沿着卷绕轴线方向K，第三边缘14c位于同侧的负极活性物质层123边缘和隔离件13边缘之间。示例地，如图14所示，负极集流部122a仅部分区域涂覆有负极活性物质层123，负极集流部122a未涂覆负极活性物质层123的区域涂覆有绝缘层124，绝缘层124位于负极活性物质层123的靠近负极凸部122b(负极极耳)的一侧，且位于同侧的负极活性物质层123的边缘和隔离件13的边缘之间，第三边缘14c可以位于绝缘层124中。
本公开实施例，通过沿着卷绕轴线K方向，位于负极弯折部121的保护层14的第三边缘14c超出负极活性物质层123但不超出隔离件13，位于负极弯折部121的保护层14的第四边缘14d超出隔离件13，由此，保护层14覆盖负极活性物质层123的同时，仅有一个边缘超出隔离件13，即可目测到保护层14位于负极弯折部121的粘贴位置，相较于两个边缘均超出隔离件13，能够降低隔离件13粘辊导致自身撕裂的风险。
在一些实施例中，沿卷绕轴线方向K，保护层14超出隔离件13的长度d1为1mm～4mm。既可以是在正极弯折部111处的保护层14超出隔离件13的长度d1为1mm～4mm，又可以是负极弯折部121处保护层14超出隔离件13的长度d1为1mm～4mm。
长度d1可以是1mm、2mm、3mm、4mm。
保护层14超出隔离件13的长度d1过小，则目测困难，保护层14超出隔离件13的长度d1过大，则在卷绕工序中存在粘辊导致保护层14撕裂的风险越大。因此，本公开实施例，将护层14超出隔离件13的长度d1控制为1mm～4mm之间，既能方便目测保护层14的粘贴位置，也能降低保护层14粘辊导致撕裂的风险。
在一些实施例中，沿卷绕轴线方向K，位于正极弯折部111的保护层14超出正极弯折部111的长度d2为4mm～6mm。和/或，沿卷绕轴线方向K，位于负极弯折部121的保护层14超出负极弯折部121的长度d2为4mm～6mm。
长度d2包括隔离件13超出极片的边缘的长度和保护层14超出隔离件13的长度。
在电极组件的制备过程中，可以先在极片上附接保护层14，再进行卷绕，卷绕后形成的卷绕结构中，极片的边缘相较于隔离件的边缘更平整，更容易测量保护层14的超出尺寸，并且在极片附件保护层14之后，卷绕之前，也方便测量保护层14超出极片的尺寸。因此，通过保护层14超出正极弯折部111和/或负极弯折部121的长度来控制保护层14超出隔离件13的超出长度，能够提升保护层14附接精度。
在一些实施例中，在正极集流体112a沿着卷绕轴线方向K的一侧设有正极极耳112b，保护层14的第一边缘14a沿着卷绕轴线方向K与正极极耳112b位于同侧。即，位于正极极耳112b同侧的第一边缘14a不超出隔离件13。
在一些实施例中，在负极集流体122a沿着卷绕轴线方向K的一侧设有负极极耳122b，保护层14的第三边缘14c沿着卷绕轴线方向K与负极极耳122b位于同侧。即，位于负极极耳122b同侧的第三边缘14a不超出隔离件13。
在卷绕工序中，极耳(正极极耳112b、负极极耳122b)的侧方通常设置有检测设备，例如检测设备可以是用于检测极耳的传感器，该传感器可以用于判断极耳是否弯折，如果弯折则认为不合格。如果位于极耳同侧的保护层14边缘(第一边缘14a、第三边缘14c)超出隔离件13，当保护层14超出的部分经过该传感器时，可能会导致传感器误报，即将合格的正极极耳误认为不合格。由此，本公开实施例，通过位于极耳同侧的保护层14边缘不超出隔离件13，能够避免极耳侧方的检测设备误报的风险。
在一些实施例中，如图8和图11所示，保护层14可以覆盖正极极片11中的正极弯折部111处的一面(第一凹面111a或第一凸面111b)的正极活性物质层113或者两面(第一凹面111a和第一凸面111b)的正极活性物质层113。而且，保护层14还可以覆盖负极极片12中的负极弯折部121处的一面(第二凹面121a或第二凸面121b)的负极活性物质层123或者两面(第二凹面121a和第二凸面121b)的负极活性物质层123。
图11为本公开另一些实施例提供的电极组件的剖面示意图。图12为图11中部分放大 示意图。
如图11和图12，在一些实施例中，沿着卷绕结构的层叠方向E，各正极弯折部111包括位于相反两侧的第一凹面111a和第一凸面111b，保护层14包括分别附接于第一凹面111a和第一凸面111b的第一保护层141和第二保护层142。
卷绕结构的层叠方向E可以是正极弯折部111的厚度方向。沿着层叠方向E可以排列有多个正极弯折部111，每个正极弯折部111包括位于相反两侧的第一凹面111a和第一凸面111b。第一凹面111a是正极弯折部111的圆弧向内凹陷的一面，第一凸面111b是正极弯折部111的圆弧向外凸出的一面。第一凹面111a相比于第一凸面111b更靠近卷绕轴线。
正极弯折部111在折弯过程中，正极弯折部111的正反两侧的表面均可能存在活性物质层脱落的风险，有可能影响电池容量，还有可能引发电池热失控的风险。本公开实施例通过在正极弯折部111的正反两侧的第一凹面111a和第一凸面111b均附接保护层14，进一步降低正极弯折部111断裂的风险，并且能够降低正极弯折部111两个表面的正极活性物质层脱落的风险，减少对电池容量的不良影响、降低电池热失控的风险。
在一些实施例中，可以在每个正极弯折部111的第一凹面111a和第一凸面111b分别附接第一保护层141和第二保护层142。这样多个正极弯折部111可以得到全面保护。
由于在层叠方向E的最内侧的正极弯折部111相较于其他正极弯折部111受到的拉伸力更大，更容易导致断裂或者正极活性物质层脱落。对此，在一些实施例中，还可以在层叠方向E的位于最内侧的正极弯折部111的第一凹面111a和第一凸面111b分别附接第一保护层141和第二保护层142。这样，最内侧的正极弯折部111得到有效保护。
在一些实施例中，如图8所示，沿着卷绕轴方向K，在至少一端，第一保护层141和第二保护层142中的一者超出另外一者。即，沿着卷绕轴方向K，第一保护层141和第二保护层142的同侧的端部相互错开(相互错位)。
例如可以是，沿着卷绕轴线方向K，同侧的第一保护层141的一端部超出第二保护层142的一端部；或者，沿着卷绕轴线方向K，同侧的第二保护层142的一端部超出第一保护层141的一端部；又或者，沿着卷绕轴线方向K，第一保护层141的两端部分别超出同侧的第二保护层142的两端部；再或者，沿着卷绕轴线方向K，第二保护层142的两端部分别超出同侧的第一保护层141的两端部。
第一保护层141和第二保护层142中的一者超出另外一者的超出尺寸可以为0～4mm。示例性地，超出尺寸可以是0mm、1mm、2mm、3mm、4mm。
在一些实施例中，沿着卷绕结构的层叠方向E，各负极弯折部121包括位于相反两侧的第二凹面121a和第二凸面121b，保护层14包括分别附接于第二凹面121a和第二凸面121b 的第三保护层143和第四保护层144。
沿着层叠方向E可以排列有多个负极弯折部121，多个负极弯折部121与多个正极弯折部111沿着层叠方向E交替分布，每个负极弯折部121包括位于相反两侧的第二凹面121a和第二凸面121b。第二凹面121a是负极弯折部121的圆弧向内凹陷的一面，第二凸面121b是负极弯折部121的圆弧向外凸出的一面。第二凹面121a相比于第二凸面121b更靠近卷绕轴线。
负极弯折部121在折弯过程中，负极弯折部121的正反两侧的表面均可能存在活性物质层脱落的风险，有可能影响电池容量，还有可能存在电池热失控的风险。本公开实施例通过在负极弯折部121的正反两侧的第二凹面121a和第二凸面121b均附接保护层14，进一步降低负极弯折部121断裂的风险，并且能够降低负极弯折部121两个表面的负极活性物质层脱落的风险，减少对电池容量的不良影响、降低电池热失控的风险。
在一些实施例中，可以在每个负极弯折部121的第二凹面121a和第二凸面121b分别附接第三保护层143和第四保护层144。这样多个负极弯折部121均可以得到全面保护。
由于在层叠方向E的最内侧的负极弯折部121相较于其他负极弯折部121受到的拉伸力更大，更容易导致断裂或者正极活性物质层脱落。
在一些实施例中，还可以在层叠方向E的位于最内侧的负极弯折部121的第二凹面121a和第二凸面121b分别附接第三保护层143和第四保护层144。这样，最内侧的负极弯折部121得到有效保护。
在一些实施例中，如图11和图12，第一保护层141包括沿着卷绕结构的卷绕方向C的第一端141a和第二端141b，第二保护层142包括在卷绕方向C的第三端142a和第四端142b，第三端142a与第一端141a沿着卷绕方向C位于同一侧且沿着卷绕方向C相互错开，和/或，第四端142b与第二端141b在卷绕方向C位于同一侧且沿着卷绕方向C相互错开。
第三端142a与第一端141a沿着卷绕方向C相互错开，是指，第三端142a与第一端141a沿着卷绕方向C不在同一位置。例如，如图12所示，沿着卷绕方向C，第三端142a超出第一端141a；或者说，第一端141a与第三端142a相比朝着逆时针方向伸出。当然，第一端141a超出第三端142a亦可。
第四端142b与第二端141b沿着卷绕方向C相互错开，是指第四端142b与第二端141b沿着卷绕方向C不在同一位置。例如，如图12所示，沿着卷绕方向C，第四端142b超出第二端141b；或者说，第四端142b与第二端141b相比朝着顺时针方向伸出。当然，第二端141b超出第四端142b亦可。
第一保护层141和第二保护层142可以是沿着卷绕方向C同侧的一端相互错开；也可以 是如图12所示那样第一保护层141和第二保护层142沿着卷绕方向C同侧的两端相互错开。例如，第三端142a与第一端141a相互错开，第四端142b与第二端141b不相互错开；或者，第四端142b与第二端141b相互错开，第三端142a与第一端141a不相互错开；或者第三端142a与第一端141a相互错开，且第四端142b与第二端141b相互错开。
由于第一保护层141和第二保护层142具有一定的厚度，沿着卷绕方向C，第一保护层141的端部和第二保护层142的端部分别与正极极片11的表面形成台阶，在卷绕结构挤压成型过程中，该台阶高度差越大，挤压隔离件13越明显，易导致隔离件13褶皱，从而阻挡隔离件13中的孔隙，甚至存在硌破隔离件的风险。本公开实施例，通过第一保护层141和第二保护层142同侧的两端相互错开，相较于非错开，能够降低各保护层层叠后的端部的台阶高度，因此，在卷绕结构挤压成型过程中，能够对隔离件13的挤压形成缓冲，降低隔离件13褶皱风险，从而减少因褶皱引起的隔离件13的孔隙被阻挡。
在一些实施例中，第三保护层143包括在卷绕结构的卷绕方向C的第五端143a和第六端143b，第四保护层144包括在卷绕方向C的第七端144a和第八端144b，第七端144a与第五端143a在卷绕方向C位于同一侧且沿着卷绕方向C相互错开，和/或，第八端144b与第六端143b在卷绕方向C的同一侧且沿着卷绕方向C相互错开。
第三保护层143和第四保护层144可以是沿着卷绕方向C一个同一侧的端部相互错开；也可以是第三保护层143和第四保护层144沿着卷绕方向C两个一侧的端部均相互错开。例如，第七端144a与第五端143a相互错开，第八端144b与第六端143b不相互错开；或者，第八端144b与第六端143b相互错开，第七端144a与第五端143a不相互错开；或者，第七端144a与第五端143a相互错开，且第八端144b与第六端143b相互错开。
本公开实施例，通过第三保护层141和第四保护层142同侧的两端相互错开，相较于非错开，能够降低各保护层层叠后的端部的台阶高度，因此，在卷绕结构挤压成型过程中，能够对隔离件13的挤压形成缓冲，降低隔离件13褶皱风险，从而减少因褶皱引起的隔离件13的孔隙被阻挡的可能性。
在一些实施例中，第三端142a与第一端141a沿着卷绕方向C的错开长度大于零且小于等于2mm；和/或，第四端142b与第二端141b沿着卷绕方向C的错开长度大于零且小于等于2mm。
示例性的，错开的长度可以是0.5mm、1mm、1.5mm、1.8mm、2mm。
在一些实施例中，第七端144a与第五端143a沿着卷绕方向C的错开长度大于零且小于等于2mm；和/或，第八端144b与第六端143b沿着卷绕方向C的错开长度大于零且小于等于2mm。
示例性的，错开的长度可以是0.5mm、1mm、1.5mm、1.8mm、2mm。
以第一保护层141和第二保护层142沿着卷绕方向C同侧的两端错开为例，若第一保护层141和第二保护层142沿着卷绕方向C同侧的两端错开的长度过小，则存在挤压隔离件13导致褶皱风险，若第一保护层141和第二保护层142沿着卷绕方向C同侧的两端错开的长度过大，则存在第一保护层141的超出隔离件13的部分与第二保护层142的超出隔离件13的部分的错开距离较大，导致第一保护层141和第二保护呈142的超出隔离件13的部分的表面露胶面积较大，在卷绕过程中，容易粘辊导致撕裂风险。因此，第一保护层141和第二保护层142沿着卷绕方向C同侧的两端错开的长度控制在大于零且小于等于2mm范围，既可以降低隔离件13褶皱风险，又可以降低粘辊导致撕裂风险。
在一些实施例中，如图6和图7，卷绕结构包括与弯折区A连接的平直区B，保护层14在卷绕结构的卷绕方向C上的至少一端延伸至平直区B与弯折区A之间的交界处或者沿着卷绕方向C超过交界处延伸至平直区B。
保护层14在卷绕结构的卷绕方向C上的仅一端延伸至平直区B与弯折区A之间的交界处或者沿着卷绕方向C超过交界处延伸至平直区B；或者，保护层14在卷绕结构的卷绕方向C上的两端均延伸至平直区B与弯折区A之间的交界处或者沿着卷绕方向C超过交界处延伸至平直区B。由此，位于正极弯折部111处的保护层14能够在卷绕方向C上覆盖正极活性物质层113，正极活性物质层113得到全面保护；位于负极弯折部121处的保护层14能够在卷绕方向C上覆盖负极活性物质层123，负极活性物质层123得到全面保护。
在一些实施例中，位于第一凹面11a处的第一保护层141和位于第一凸面111b处的第二保护层142中的至少一者具有用于供离子透过的孔隙。
可以仅在正极弯折部111的位于第一凹面11a处的至少部分第一保护层141具有用于供离子透过的孔隙。或者，仅在正极弯折部111的位于第一凸面111b处的至少部分第二保护层142具有用于供离子透过的孔隙。或者在正极弯折部111的位于第一凹面11a处的至少部分第一保护层141和位于第一凸面111b处的至少部分第二保护层142均具有用于供离子透过的孔隙。
离子可以是活性物质中的活性离子，例如，电池为锂离子电池时，活性离子为锂离子；电池为钠离子电池时，活性离子可以是钠离子；电池为镁离子电池时，活性离子可以是镁离子；当然离子也可以是活性物质中存在的其他可能的活性离子。
保护层具有用于供离子透过的孔隙，降低或防止电池容量的损失。
位于第一凹面11a处的第一保护层141和位于第一凸面111b处的第二保护层142具有用于供离子透过的孔隙，能够保护正极弯折部111断裂和各自的活性物质脱落的风险，同时 还能降低因保护层附接到正极弯折部111对正极弯折部111处的正极活性物质层113中正极活性物质脱出的影响。
在一些实施例中，位于第一凹面11a处的第一保护层141和位于第一凸面111b处的第二保护层142均包括用于阻挡离子的阻挡部。
由于负极弯折部121的负极活性物质层的嵌锂位少于其相邻的正极弯折部111的正极活性物质层能够提供的锂离子数量，因此，可能会导致析锂现象。本公开实施例，通过第一保护层141上的用于阻挡离子的阻挡部，能够阻挡一部分正极活性物质层提供的锂离子数量，因此能够降低析锂现象。
在一些实施例中，位于第二凹面121a处的第三保护层143和位于第二凸面121b处的第四保护层144均具有用于供离子透过的孔隙。
由于负极弯折部121的负极活性物质层的嵌锂位少于其相邻的正极弯折部111的正极活性物质层能够提供的锂离子数量，换言之，正极弯折部111的正极活性物质层能够提供的锂离子数量多于负极弯折部121的负极活性物质层的嵌锂位，如果负极弯折部121上负极活性物质层被阻挡，更容易导致负极活性物质层的嵌锂位不足，更容易导致析锂现象。因此，负极弯折部121的第二凹面121a处的第三保护层143和第二凸面121b处的第四保护层144均具有用于供离子透过的孔隙，这样保护负极弯折部121的同时，还能降低析锂现象。
上述具有用于供离子透过的孔隙的保护层的透气度为220±70sec/100cc，(sec单位为秒，cc单位为立方厘米)。关于透气度的测定，例如可以根据标准文件GB/T36363-2018进行测定，即，在测试温湿度、常压环境中，测试仪器施加1.21kPa压力下，100ml空气通过面积为6.45cm2隔离件所需的时间。其中，施加的1.21kPa压力为恒定压力，所通过的6.45cm2面积为固定面积。
上述保护层中具有用于供离子透过的孔隙的最小尺寸范围可以为100nm～400nm。示例性地，孔隙的最小尺寸范围可以为100nm、120nm、150nm、200nm、210nm、220nm、250nm、270nm、300nm、310nm、320nm、330nm、340nm、350nm、360nm、370nm、380nm、390nm、400nm。可以采用扫码电子显微镜电镜测量孔隙的最小尺寸。
本公开实施例还提供一种电池单体160，包括：壳体20和至少一个上文提到的电极组件10，电极组件10容纳于壳体20内。
本公开实施例还提供一种电池100，包括：箱体110和至少一个上文提到的电池单体160，电池单体160收容于箱体110内。
本公开实施例还提供一种用电装置，用电装置包括用于提供电能的至少一个上文提到的电池单体160或者电池100。
本公开实施例还提供一种储能装置，包括上文提到的电池，电池能够储存电能且能够提供电能。
本公开实施例还提供一种电极组件制备方法，如图15所示，包括：
步骤S1:提供正极极片、负极极片和隔离件；
步骤S2:针对正极极片和/或负极极片附接保护层；
步骤S3:对正极极片、负极极片及隔离件进行层叠卷绕形成卷绕结构，其中，在卷绕结构中，在正极极片与负极极片之间夹置有隔离件，卷绕结构包括弯折区，正极极片包括位于弯折区的至少一个正极弯折部，负极极片包括位于弯折区的至少一个负极弯折部，沿着卷绕结构的卷绕轴线方向，隔离件的两端超出正极弯折部和负极弯折部，在正极弯折部的表面和/或负极弯折部的表面粘贴有保护层，沿着卷绕结构的卷绕轴线方向，保护层的至少一端超出隔离件。
本公开实施例，可以先对正极极片和/或负极极片附接保护层，再进行卷绕工序。其中，对正极极片和/或负极极片附接保护层可以在极片模切工序进行，然后在进行卷绕工序。对正极极片和/或负极极片附接保护层还可以是在边卷绕边附接保护层，例如，卷绕设备中集成粘贴模块，在卷绕设备卷绕的过程中，将保护层粘贴在正极极片和/或负极极片。
以上各实施例仅用以说明本公开的技术方案，而非对其限制；尽管参照前述各实施例对本公开进行了详细的说明，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公开各实施例技术方案的范围，其均应涵盖在本公开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。本公开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。
工业实用性
通过本公开，提供了一种降低热失控风险的电极组件及其制备方法、电池单体、电池、用电装置、储能装置。通过在正极弯折部和负极弯折部附接保护层，能够降低正极弯折部和负极弯折部折弯时断裂和活性物质脱落的风险，从而降低电极组件、电池单体乃至电池整体的热失控的风险；保护层超出隔离件，能够使胶纸完全覆盖正、负极极片而对其进行可靠的保护，而且能够在电池制造过程中通过露出的部分目测到保护层的附接位置，及时确认附接位置的准确性。

Claims (26)

  1. 一种电极组件，包括：
    卷绕结构，所述卷绕结构由包括正极极片和负极极片的层叠体卷绕而成，在所述正极极片与所述负极极片之间夹置有隔离件，所述卷绕结构包括弯折区，所述正极极片包括位于所述弯折区的至少一个正极弯折部，所述负极极片包括位于所述弯折区的至少一个负极弯折部，沿着所述卷绕结构的卷绕轴线方向，所述隔离件的两端超出所述正极弯折部和所述负极弯折部；以及
    保护层，附接于所述正极弯折部的表面和/或所述负极弯折部的表面，沿着所述卷绕结构的卷绕轴线方向，所述保护层的至少一端超出所述隔离件。
  2. 根据权利要求1所述的电极组件，其中，
    所述保护层以粘贴或静电吸附的方式附接于所述正极弯折部的表面和/或所述负极弯折部的表面。
  3. 根据权利要求1或2所述的电极组件，其中，
    沿着所述卷绕结构的层叠方向，各所述正极弯折部包括位于相反两侧的第一凹面和第一凸面，
    所述保护层包括分别附接于所述第一凹面和所述第一凸面的第一保护层和第二保护层。
  4. 根据权利要求1至3中任一项所述的电极组件，其中，
    沿着所述卷绕结构的层叠方向，各所述负极弯折部包括位于相反两侧的第二凹面和第二凸面，
    所述保护层包括分别附接于所述第二凹面和所述第二凸面的第三保护层和第四保护层。
  5. 根据权利要求1至4中任一项所述的电极组件，其中，
    所述正极极片包括正极集流体以及设置于所述正极集流体的表面的正极活性物质层，所述保护层覆盖所述正极极片中的所述正极弯折部处的所述正极活性物质层；和/或，
    所述负极极片包括负极集流体以及设置于所述负极集流体的表面的负极活性物质层，所述保护层覆盖所述负极极片中的所述负极弯折部处的所述负极活性物质层。
  6. 根据权利要求5所述的电极组件，其中，
    在所述正极弯折部，沿着所述卷绕轴线方向，位于所述正极弯折部的所述保护层的第一边缘超出所述正极活性物质层但不超出所述隔离件，位于所述正极弯折部的所述保护层的第二边缘超出所述隔离件，其中，所述第一边缘位于所述保护层沿着所述卷绕轴线方向的一端，所述第二边缘位于所述保护层沿着所述卷绕轴线方向的另一端；和/或，
    在所述负极弯折部，沿着所述卷绕轴线方向，位于所述负极弯折部的所述保护层的第 三边缘超出所述负极活性物质层但不超出所述隔离件，位于所述负极弯折部的所述保护层的第四边缘超出所述隔离件，其中，所述第三边缘位于所述保护层的沿着所述卷绕轴线方向的一端，所述第四边缘位于所述保护层的沿着所述卷绕轴线方向的另一端。
  7. 根据权利要求6所述的电极组件，其中，
    在所述正极集流体，在所述卷绕轴线方向的一侧设有正极极耳，所述保护层的所述第一边缘沿着所述卷绕轴线方向与所述正极极耳位于同侧；和/或，
    在所述负极集流体，在所述卷绕轴线方向的一侧设有负极极耳，所述保护层的所述第三边缘沿着所述卷绕轴线方向与所述负极极耳位于同侧。
  8. 根据权利要求1至7中任一项所述的电极组件，其中，
    沿所述卷绕轴线方向，所述保护层超出所述正极弯折部的长度为4mm～6mm；和/或，
    沿所述卷绕轴线方向，所述保护层超出所述负极弯折部的长度为4mm～6mm。
  9. 根据权利要求1至8中任一项所述的电极组件，其中，
    沿所述卷绕轴线方向，所述保护层超出所述隔离件的长度为1mm～4mm。
  10. 根据权利要求3所述的电极组件，其中，
    沿着所述卷绕轴方向，在至少一端，所述第一保护层和所述第二保护层中的一者超出另外一者。
  11. 根据权利要求3所述的电极组件，其中，
    所述第一保护层包括沿着所述卷绕结构的卷绕方向位于两端的第一端和第二端，所述第二保护层包括沿着所述卷绕方向位于两端的第三端和第四端，
    所述第三端与所述第一端在所述卷绕方向的同一侧且沿着所述卷绕方向相互错开，和/或，所述第四端与所述第二端在所述卷绕方向的同一侧且沿着所述卷绕方向相互错开。
  12. 根据权利要求11所述的电极组件，其中，
    所述第三端与所述第一端沿着所述卷绕方向的错开长度大于零且小于等于2mm；和/或，
    所述第四端与所述第二端沿着所述卷绕方向的错开长度大于零且小于等于2mm。
  13. 根据权利要求4所述的电极组件，其中，
    所述第三保护层包括沿着所述卷绕结构的卷绕方向位于两端的第五端和第六端，所述第四保护层包括沿着所述卷绕方向位于两端的第七端和第八端，
    所述第七端与所述第五端在所述卷绕方向的同一侧且沿着所述卷绕方向相互错开，和/或，所述第八端与所述第六端在所述卷绕方向的同一侧且沿着所述卷绕方向相互错开。
  14. 根据权利要求13所述的电极组件，其中，
    所述第七端与所述第五端沿着所述卷绕方向的错开长度大于零且小于等于2mm；和/或，
    所述第八端与所述第六端沿着所述卷绕方向的错开长度大于零且小于等于2mm。
  15. 根据权利要求1至14中任一项所述的电极组件，其中，
    所述卷绕结构包括与所述弯折区连接的平直区，
    所述保护层在所述卷绕结构的卷绕方向上的至少一端延伸至所述平直区与所述弯折区之间的交界处或者沿着所述卷绕方向超过所述交界处延伸至所述平直区。
  16. 根据权利要求1至15中任一项所述的电极组件，其中，
    所述正极极片包括位于所述弯折区的沿着所述卷绕结构的层叠方向排列的多个所述正极弯折部，所述保护层至少粘贴于沿着所述层叠方向位于最内侧的所述正极弯折部；和/或，
    所述负极极片包括位于所述弯折区的沿着所述卷绕结构的层叠方向排列的多个所述负极弯折部，所述保护层至少粘贴于沿着所述层叠方向位于最内侧的所述负极弯折部。
  17. 根据权利要求1至16中任一项所述的电极组件，其中，
    所述保护层的材质为聚对苯二甲酸乙二酯、聚丙烯、聚乙烯、聚酰亚胺或无纺布。
  18. 根据权利要求3所述的电极组件，其中，
    位于所述第一凹面处的所述第一保护层和位于所述第一凸面处的所述第二保护层中的至少一者具有用于供离子透过的孔隙；或者，
    位于所述第一凹面处的所述第一保护层和位于所述第一凸面处的所述第二保护层均包括用于阻挡离子的阻挡部。
  19. 根据权利要求4所述的电极组件，其中，
    位于所述第二凹面处的所述第三保护层和位于所述第二凸面处的所述第四保护层均具有用于供离子透过的孔隙。
  20. 根据权利要求18或19所述的电极组件，其中，
    具有用于供离子透过的孔隙的所述保护层的透气度为220±70sec/100cc。
  21. 根据权利要求18或19所述的电极组件，其中，
    所述孔隙的孔隙为100nm～400nm。
  22. 一种电池单体，其中，包括：壳体和至少一个如权利要求1-21中任一项所述的电极组件，所述电极组件容纳于所述壳体内。
  23. 一种电池，其中，包括：箱体和至少一个如权利要求22所述的电池单体，所述电池单体收容于所述箱体内。
  24. 一种用电装置，其中，所述用电装置包括用于提供电能的至少一个如权利要求22所述的电池单体或者如权利要求23所述的电池。
  25. 一种储能装置，其中，包括如权利要求23所述的电池，所述电池能够储存电能且 能够提供电能。
  26. 一种电极组件制备方法，其中，包括：
    提供正极极片、负极极片和隔离件；
    针对正极极片和/或负极极片附接保护层；
    对所述正极极片、所述负极极片及所述隔离件进行层叠卷绕形成卷绕结构，其中，
    在所述卷绕结构中，在所述正极极片与所述负极极片之间夹置有隔离件，所述卷绕结构包括弯折区，所述正极极片包括位于所述弯折区的至少一个正极弯折部，所述负极极片包括位于所述弯折区的至少一个负极弯折部，沿着所述卷绕结构的卷绕轴线方向，所述隔离件的两端超出所述正极弯折部和所述负极弯折部，在所述正极弯折部的表面和/或所述负极弯折部的表面粘贴有所述保护层，沿着所述卷绕结构的卷绕轴线方向，所述保护层的至少一端超出所述隔离件。
PCT/CN2023/135705 2023-11-30 2023-11-30 电极组件及其制备方法、电池单体、电池、用电装置、储能装置 Pending WO2025112002A1 (zh)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/CN2023/135705 WO2025112002A1 (zh) 2023-11-30 2023-11-30 电极组件及其制备方法、电池单体、电池、用电装置、储能装置

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2023/135705 WO2025112002A1 (zh) 2023-11-30 2023-11-30 电极组件及其制备方法、电池单体、电池、用电装置、储能装置

Publications (1)

Publication Number Publication Date
WO2025112002A1 true WO2025112002A1 (zh) 2025-06-05

Family

ID=95896119

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2023/135705 Pending WO2025112002A1 (zh) 2023-11-30 2023-11-30 电极组件及其制备方法、电池单体、电池、用电装置、储能装置

Country Status (1)

Country Link
WO (1) WO2025112002A1 (zh)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2021026911A (ja) * 2019-08-06 2021-02-22 株式会社豊田自動織機 蓄電装置
CN212810367U (zh) * 2020-08-21 2021-03-26 宁德时代新能源科技股份有限公司 电极组件、电池单体、电池和用电装置
CN113728486A (zh) * 2021-02-09 2021-11-30 宁德新能源科技有限公司 电化学装置和电子装置
CN115623875A (zh) * 2021-05-12 2023-01-17 宁德时代新能源科技股份有限公司 电极组件、电池单体、电池以及用电装置
CN115692863A (zh) * 2022-11-04 2023-02-03 厦门海辰储能科技股份有限公司 电芯的结构与包胶方法、电池单体、储能装置及用电设备

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2021026911A (ja) * 2019-08-06 2021-02-22 株式会社豊田自動織機 蓄電装置
CN212810367U (zh) * 2020-08-21 2021-03-26 宁德时代新能源科技股份有限公司 电极组件、电池单体、电池和用电装置
CN113728486A (zh) * 2021-02-09 2021-11-30 宁德新能源科技有限公司 电化学装置和电子装置
CN115623875A (zh) * 2021-05-12 2023-01-17 宁德时代新能源科技股份有限公司 电极组件、电池单体、电池以及用电装置
CN115692863A (zh) * 2022-11-04 2023-02-03 厦门海辰储能科技股份有限公司 电芯的结构与包胶方法、电池单体、储能装置及用电设备

Similar Documents

Publication Publication Date Title
CN115715438B (zh) 电池单体及其制造方法和制造系统、电池以及用电装置
CN100446333C (zh) 袋状锂二次电池
CN101978547B (zh) 方形电池
EP2602840B1 (en) Secondary battery pouch having improved stability, pouch-type secondary battery using same, and medium- or large-sized battery pack
US20230352780A1 (en) Secondary Battery and Battery Module Including the Same
EP4250457A1 (en) Battery module and battery pack including same
JP7405326B2 (ja) 二次電池および二次電池の製造方法
CN215896616U (zh) 电极组件、电池单体、电池及用电设备
US12506155B2 (en) Electrode assembly, battery cell, battery, and method and device for manufacturing electrode assembly
WO2025092662A1 (zh) 电芯、电池以及用电装置
CN221596535U (zh) 电极组件、电池单体、电池、用电装置及储能装置
WO2025112002A1 (zh) 电极组件及其制备方法、电池单体、电池、用电装置、储能装置
KR100601549B1 (ko) 파우치형 리튬 이차전지
CN121646844A (zh) 电池和用电装置
CN116114095B (zh) 电极组件、电池单体、电池以及用电装置
KR102821617B1 (ko) 이차전지 및 이를 포함하는 디바이스
WO2025025299A1 (zh) 电池单体、电池和用电设备
CN119833701B (zh) 电池单体的制造方法、端盖组件、电池单体及电池装置
CN222562801U (zh) 一种软包电池
CN224110267U (zh) 电池
CN223260639U (zh) 电池单体、电池装置和储能装置
CN221041311U (zh) 盖板组件及电芯
CN219303701U (zh) 电极组件、电池单体、电池及用电装置
WO2025091814A1 (zh) 电极组件及其贴胶方法、电池单体、电池及用电装置
US20240429506A1 (en) Secondary battery and battery module including the same

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 23959913

Country of ref document: EP

Kind code of ref document: A1