CN112768627B

CN112768627B - Electrode assembly, battery cell, battery, and method and apparatus for manufacturing electrode assembly

Info

Publication number: CN112768627B
Application number: CN202110373648.3A
Authority: CN
Inventors: 许虎; 金海族; 刘江; 李星; 梁成都; 曾毓群
Original assignee: Jiangsu Contemporary Amperex Technology Ltd
Current assignee: Jiangsu Contemporary Amperex Technology Ltd
Priority date: 2021-04-07
Filing date: 2021-04-07
Publication date: 2021-07-20
Anticipated expiration: 2041-04-07
Also published as: CN112768627A

Abstract

The embodiment of the application provides an electrode assembly, a battery monomer, a battery, and a manufacturing method and equipment of the electrode assembly, and belongs to the technical field of batteries. The electrode assembly comprises a positive electrode pole piece and a negative electrode pole piece, wherein the positive electrode pole piece and the negative electrode pole piece are wound along the winding direction to form a winding structure. The positive electrode sheet comprises a plurality of first active material layer regions and at least one first inactive material layer region, and the first inactive material layer regions are located between two adjacent first active material layer regions in the axial direction of the winding structure. The first inactive material layer region is provided with a first flow guide through hole, and the first flow guide through hole is configured to penetrate through two sides of the positive pole piece in the thickness direction. According to the electrode assembly with the structure, the first flow guide through holes are formed in the first inactive material layer area of the positive electrode plate, so that electrolyte can flow between the electrode plates, the infiltration effect of the electrolyte on the electrode assembly is improved, and the occurrence of a lithium separation phenomenon is reduced.

Description

Electrode assembly, battery cell, battery, and method and apparatus for manufacturing electrode assembly

Technical Field

The application relates to the technical field of batteries, in particular to an electrode assembly, a battery cell, a battery and a manufacturing method and equipment of the electrode assembly.

Background

A rechargeable battery, which may be referred to as a secondary battery, refers to a battery that can be continuously used by activating an active material by charging after the battery is discharged. Rechargeable batteries are widely used in electronic devices such as mobile phones, notebook computers, battery cars, electric automobiles, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and electric tools, etc.

Lithium separation is a common abnormal phenomenon of a lithium battery, and lithium ions which cannot be inserted into a negative electrode can only obtain electrons on the surface of the negative electrode due to the abnormality that the lithium insertion space of the negative electrode is insufficient, the lithium ion migration resistance is too large, the lithium ions are separated from the positive electrode too fast but cannot be inserted into the negative electrode in equal quantity, and the like, so that a lithium simple substance is formed. The lithium separation can affect the charging efficiency and energy density of lithium ions, lithium crystals can be formed when the lithium separation is serious, and the lithium crystals can pierce an isolating membrane to cause internal short circuit thermal runaway, so that the safety of the battery is seriously damaged.

Therefore, how to reduce the lithium deposition is an urgent technical problem to be solved in the battery technology.

Disclosure of Invention

The embodiment of the application provides an electrode assembly, a single battery, a battery and a manufacturing method and equipment of the electrode assembly, which can effectively reduce the occurrence of a lithium precipitation phenomenon.

In a first aspect, an embodiment of the present application provides an electrode assembly, including a positive electrode plate and a negative electrode plate, where the positive electrode plate and the negative electrode plate are wound along a winding direction and form a winding structure; the positive pole piece comprises a plurality of first active material layer regions and at least one first inactive material layer region, and the first inactive material layer regions are positioned between two adjacent first active material layer regions in the axial direction of the winding structure; the first inactive material layer region is provided with a first flow guide through hole, and the first flow guide through hole is configured to penetrate through two sides of the positive pole piece in the thickness direction.

In the scheme, the first inactive material layer region is arranged on the positive pole piece, so that the quantity of lithium ions separated from the positive pole piece during charging can be reduced, and the occurrence of a lithium separation phenomenon is reduced. The first flow guide through holes penetrating through the two sides of the positive pole piece in the thickness direction are formed in the first inactive material layer region, so that electrolyte can flow between the pole pieces, the infiltration effect of the electrolyte on an electrode assembly is improved, and the occurrence of a lithium separation phenomenon is reduced.

In some embodiments, the first inactive material layer region is provided with a plurality of first fluid guide through holes spaced apart in the winding direction.

In the above scheme, the first inactive material layer region is provided with the plurality of first flow guide through holes distributed at intervals along the winding direction, and the electrolyte can flow between the pole pieces through the plurality of first flow guide through holes, so that the infiltration effect of the electrolyte on the electrode assembly is further improved.

In some embodiments, in the winding direction, the distance between every two adjacent first flow guide through holes is gradually increased; or in the winding direction, the distance between every two adjacent first flow guide through holes is equal.

In some embodiments, a second flow guiding through hole is provided in the negative electrode plate, and the second flow guiding through hole is configured to penetrate through both sides of the negative electrode plate in the thickness direction.

In the above scheme, the negative pole piece is provided with the second flow guide through holes which penetrate through the two sides of the negative pole piece in the thickness direction, so that the electrolyte can flow between the pole pieces through the first flow guide through holes and also can flow between the pole pieces through the second flow guide through holes, and the infiltration effect of the electrolyte on the electrode assembly is further improved.

In some embodiments, the negative electrode sheet includes a second active material layer region, the second current guiding through hole is disposed in the second active material layer region, and the first active material layer region and the first inactive material layer region are both disposed opposite to the second active material layer region.

In the technical scheme, the first active material layer area and the first inactive material layer area of the positive electrode plate are arranged opposite to the second active material layer area of the negative electrode plate, namely, the parts of the negative electrode plate opposite to the first active material layer area and the first inactive material layer area are provided with the negative electrode active material layer, so that the bending resistance of the electrode assembly in the first inactive material layer area is improved.

In some embodiments, the negative electrode sheet includes a plurality of second active material layer regions and at least one second inactive material layer region, the second inactive material layer region is located between two adjacent second active material layer regions in the axial direction, and the second flow guiding through hole is disposed in the second inactive material layer region; wherein the second active material layer region is disposed opposite the first active material layer region, the second inactive material layer region is disposed opposite the first inactive material layer region, and a width of the second inactive material layer region in the axial direction does not exceed a width of the first inactive material layer region in the axial direction.

In the above scheme, the second inactive material layer region is arranged on the negative electrode plate, that is, the negative electrode plate is not provided with the negative active material layer in the region, so that the production cost can be effectively reduced, and the economy is better. Because the first active material layer region and the second active material layer region are arranged oppositely, the first inactive material layer region and the second inactive material layer region are arranged oppositely, and the width of the second inactive material layer region in the axial direction of the winding structure is not more than that of the first inactive material layer region in the axial direction of the winding structure, the occurrence of the lithium separation phenomenon can be effectively reduced.

In some embodiments, a plurality of second flow guiding through holes are arranged on the negative pole piece and distributed at intervals along the winding direction.

In the above scheme, the plurality of second flow guide through holes distributed at intervals along the winding direction are formed in the negative pole piece, and the electrolyte can flow between the pole pieces through the plurality of second flow guide through holes, so that the infiltration effect of the electrolyte on the electrode assembly is further improved.

In some embodiments, in the winding direction, the distance between every two adjacent second flow guide through holes is gradually increased; or in the winding direction, the distance between every two adjacent second flow guide through holes is equal.

In some embodiments, the winding structure is provided with a flow guide channel for allowing the electrolyte to flow from the outside of the winding structure to the inside of the winding structure; the plurality of first flow guide through holes and the plurality of second flow guide through holes form the flow guide channel.

In the above scheme, the plurality of first diversion through holes and the plurality of second diversion through holes form diversion channels, electrolyte outside the winding structure can enter the winding structure through the diversion channels, meanwhile, gas generated inside the electrode assembly can be discharged through the electrode assembly, and the exhaust effect of the electrode assembly and the infiltration effect of the electrolyte on the electrode assembly are improved.

In some embodiments, the winding structure is provided with a plurality of flow guide channels distributed at intervals along the winding direction.

In the above scheme, the winding structure is provided with the plurality of flow guide channels distributed at intervals along the winding direction, electrolyte outside the winding structure can enter the electrode assembly from different directions through the plurality of flow guide channels, and gas generated inside the electrode assembly can be discharged from different directions through the plurality of flow guide channels, so that the exhaust effect of the electrode assembly and the infiltration effect of the electrolyte on the electrode assembly are further improved.

In some embodiments, the flow guide channel extends along a straight line, and the extending direction of the flow guide channel is arranged at a non-zero included angle with the axial direction.

In the scheme, the flow guide channel extends along a straight line, so that the smoothness of the electrolyte and the gas flowing in the flow guide channel is improved, and the electrolyte infiltration and the gas discharge are facilitated.

In some embodiments, the direction of extension is perpendicular to the axial direction.

In the scheme, the extending direction of the flow guide channel is vertical to the axial direction, so that the flow paths of the electrolyte and the gas can be shortened, and the infiltration efficiency and the gas discharge efficiency of the electrolyte can be effectively improved.

In some embodiments, the flow guide channel comprises a plurality of flow guide through holes distributed at intervals along the extension direction of the flow guide channel, and the plurality of flow guide through holes comprise a plurality of first flow guide through holes and a plurality of second flow guide through holes; in the direction that the flow guide channel extends towards the inside of the winding structure, the aperture of each flow guide through hole in the flow guide channel is gradually reduced; or the apertures of all the flow guide through holes in the flow guide channel are equal.

In the above scheme, if the aperture of each flow guide through hole in the flow guide channel is gradually reduced in the extending direction of the flow guide channel towards the inside of the winding structure, the requirement that the inner ring pole piece has a small infiltration requirement on the electrolyte and the outer ring pole piece has a large infiltration requirement on the electrolyte can be met. If the apertures of the flow guide through holes in the flow guide channel are equal, the process of forming holes in the negative pole piece and the positive pole piece can be simplified.

In some embodiments, the coiled construction comprises an outer hoop section and an inner hoop section arranged concentrically, the inner hoop section being located inside the outer hoop section; the first flow guide through hole is formed in the positive pole piece in the outer ring portion, the second flow guide through hole is formed in the negative pole piece in the outer ring portion, and the flow guide channel is formed in the outer ring portion.

In the above scheme, the flow guide channel is formed in the outer ring part, and the electrolyte can enter the inside of the winding structure through the flow guide channel so as to infiltrate the pole piece in the outer ring part. The first diversion through hole and the second diversion through hole are respectively arranged on the positive pole piece and the negative pole piece in the outer circle part, the positive pole piece in the inner circle part is not provided with the first diversion through hole, the negative pole piece in the inner circle part is not provided with the second diversion through hole, namely, the pole piece in the inner circle part is not punched, so that the production cost can be effectively reduced, and the economical efficiency is better.

In some embodiments, the coiled construction comprises an outer hoop section and an inner hoop section arranged concentrically, the inner hoop section being located inside the outer hoop section; the positive pole pieces in the outer ring part and the inner ring part are provided with the first flow guide through holes, the negative pole pieces in the outer ring part and the inner ring part are provided with the second flow guide through holes, and the flow guide channels are formed in the outer ring part and the inner ring part; the aperture of the first flow guide through hole in the inner ring part is smaller than that of the first flow guide through hole in the outer ring part, and the aperture of the second flow guide through hole in the inner ring part is smaller than that of the second flow guide through hole in the outer ring part.

In the above scheme, the aperture of the first flow guide through hole in the inner ring part is smaller than that of the first flow guide through hole in the outer ring part, and the aperture of the second flow guide through hole in the inner ring part is smaller than that of the second flow guide through hole in the outer ring part, so that the aperture of the flow guide through hole on the pole piece in the outer ring part is relatively large, and the aperture of the flow guide through hole on the pole piece in the inner ring part is relatively small. The aperture of the flow guide through hole on the pole piece in the outer ring part is relatively large, so that the electrolyte outside the winding structure can quickly enter the electrode assembly through the flow guide through hole on the pole piece in the outer ring part; the flow guide through holes in the pole pieces in the inner ring part are relatively small, so that the flow guide through holes are conveniently formed in the pole pieces in the inner ring part.

In some embodiments, the interior of the winding structure is formed with a central bore extending in the axial direction, the flow guide passage communicating with the central bore.

In the scheme, the flow guide channel is communicated with the central hole, and the electrolyte can enter the central position of the winding structure through the flow guide channel, so that the electrolyte can infiltrate the innermost pole piece, and the gas in the central hole can be discharged conveniently.

In a second aspect, embodiments of the present application provide a battery cell, including a case and the electrode assembly provided in any one of the embodiments of the first aspect; the electrode assembly is received in the case.

In a third aspect, an embodiment of the present application provides a battery, including a case and a battery cell provided in any one of embodiments of the second aspect; the battery unit is accommodated in the box body.

In a fourth aspect, an embodiment of the present application provides an electric device, including the battery provided in any one of the embodiments of the third aspect.

In a fifth aspect, embodiments of the present application provide a method for manufacturing an electrode assembly, including:

providing a positive pole piece and a negative pole piece; winding the negative pole piece and the positive pole piece along a winding direction to form a winding structure; the positive pole piece comprises a plurality of first active material layer regions and at least one first inactive material layer region, and the first inactive material layer regions are positioned between two adjacent first active material layer regions in the axial direction of the winding structure; the first inactive material layer region is provided with a first flow guide through hole which is configured to penetrate through both sides of the positive electrode plate in the thickness direction.

In a sixth aspect, embodiments of the present application further provide an apparatus for manufacturing an electrode assembly, including:

the device comprises a providing device, a control device and a control device, wherein the providing device is used for providing a positive pole piece and a negative pole piece; the assembling device is used for winding the negative pole piece and the positive pole piece along the winding direction to form a winding structure; the positive pole piece comprises a plurality of first active material layer regions and at least one first inactive material layer region, and the first inactive material layer regions are positioned between two adjacent first active material layer regions in the axial direction of the winding structure; the first inactive material layer region is provided with a first flow guide through hole which is configured to penetrate through both sides of the positive electrode plate in the thickness direction.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.

FIG. 1 is a schematic illustration of a vehicle according to some embodiments of the present application;

fig. 2 is an exploded view of a battery provided in accordance with some embodiments of the present application;

fig. 3 is an exploded view of the battery cell shown in fig. 2;

FIG. 4 is a schematic view of a winding of an electrode assembly provided in accordance with certain embodiments of the present application;

FIG. 5 is a cross-sectional view of a positive pole piece provided by some embodiments of the present application;

fig. 6 is a schematic structural diagram of the positive electrode sheet provided in some embodiments of the present application after being unfolded;

fig. 7 is a schematic structural diagram of a positive electrode sheet according to another embodiment of the present application after being unfolded;

FIG. 8 is a graph illustrating the positional relationship of the positive electrode tab, the separator, and the negative electrode tab according to some embodiments of the present disclosure;

FIG. 9 is a graph showing the positional relationship of the positive electrode tab, separator and negative electrode tab according to still other embodiments of the present application;

fig. 10 is a schematic structural view of a negative electrode tab provided in some embodiments of the present application after being unfolded;

fig. 11 is a schematic structural view of a negative electrode tab according to another embodiment of the present application after being unfolded;

FIG. 12 is a schematic structural view of an electrode assembly provided in accordance with certain embodiments of the present application;

FIG. 13 is a schematic view of an electrode assembly according to another embodiment of the present application;

FIG. 14 is a schematic view of an electrode assembly according to further embodiments of the present application;

FIG. 15 is a schematic structural view of an electrode assembly provided in accordance with further embodiments of the present application;

FIG. 16 is a schematic structural view of an electrode assembly provided in accordance with still other embodiments of the present application;

fig. 17 is a flow chart of a method of manufacturing an electrode assembly provided by some embodiments of the present application;

fig. 18 is a schematic block diagram of an apparatus for manufacturing an electrode assembly provided in some embodiments of the present application.

Icon: 10-a box body; 11-a first part; 12-a second part; 13-a containment space; 20-a battery cell; 21-a housing; 211-a housing; 212-a cover; 213-a sealed space; 22-an electrode assembly; 221-positive pole piece; 2211-positive current collector; 2212-positive electrode active material layer; 2213 — first active material layer region; 2214-first inactive material layer region; 2215-first flow guide through hole; 2216-first winding start; 2217-first winding to receive tail end; 222-a negative pole piece; 2221-negative current collector; 2222 — negative electrode active material layer; 2223-second flow-directing through holes; 2224-second active material layer region; 2225-second inactive material layer region; 2226-second winding start end; 2227-second winding tailing end; 223-a barrier film; 224-a flow guide channel; 225-center hole; 226-an outer ring portion; 227-an inner collar portion; 23-electrode terminals; 24-a pressure relief mechanism; 100-a battery; 200-a controller; 300-a motor; 1000-a vehicle; 1100-providing a device; 1200-an assembly device; 2000-manufacturing equipment; a-the winding direction; b-axial direction.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the description of the application in the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "including" and "having," and any variations thereof, in the description and claims of this application and the description of the above figures are intended to cover non-exclusive inclusions. The terms "first," "second," and the like in the description and claims of this application or in the above-described drawings are used for distinguishing between different elements and not for describing a particular sequential or chronological order.

Reference in the specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the specification. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "attached" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

In the embodiments of the present application, like reference numerals denote like parts, and a detailed description of the same parts is omitted in different embodiments for the sake of brevity. It should be understood that the thickness, length, width and other dimensions of the various components in the embodiments of the present application and the overall thickness, length, width and other dimensions of the integrated device shown in the drawings are only exemplary and should not constitute any limitation to the present application.

The appearances of "a plurality" in this application are intended to mean more than two (including two).

In the present application, the battery cell may include a lithium ion secondary battery, a lithium ion primary battery, a lithium sulfur battery, a sodium lithium ion battery, a sodium ion battery, a magnesium ion battery, or the like, which is not limited in the embodiments of the present application. The battery cell may be a cylinder, a flat body, a rectangular parallelepiped, or other shapes, which is not limited in the embodiments of the present application. The battery cells are generally divided into three types in an encapsulation manner: the cylindrical battery monomer, the square battery monomer and the soft package battery monomer are also not limited in the embodiment of the application.

Reference to a battery in embodiments of the present application refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. For example, the battery referred to in the present application may include a battery module or a battery pack, etc. Batteries generally include a case for enclosing one or more battery cells. The box can avoid liquid or other foreign matters to influence the charging or discharging of battery monomer.

The battery monomer comprises an electrode assembly and electrolyte, wherein the electrode assembly comprises a positive plate, a negative plate and an isolating membrane. The battery cell mainly depends on metal ions moving between the positive plate and the negative plate to work. The positive plate comprises a positive current collector and a positive active substance layer, wherein the positive active substance layer is coated on the surface of the positive current collector, the positive current collector which is not coated with the positive active substance layer protrudes out of the positive current collector which is coated with the positive active substance layer, and the positive current collector which is not coated with the positive active substance layer is used as a positive electrode lug. Taking a lithium ion battery as an example, the material of the positive electrode current collector may be aluminum, and the positive electrode active material may be lithium cobaltate, lithium iron phosphate, ternary lithium, lithium manganate, or the like. The negative pole piece includes negative pole mass flow body and negative pole active substance layer, and the surface of negative pole mass flow body is scribbled to the negative pole active substance layer, and the negative pole mass flow body protrusion in the negative pole mass flow body of having scribbled the negative pole active substance layer of not scribbling the negative pole active substance layer, and the negative pole mass flow body of not scribbling the negative pole active substance layer is as negative pole utmost point ear. The material of the negative electrode current collector may be copper, and the negative electrode active material may be carbon, silicon, or the like. In order to ensure that the fuse is not fused when a large current is passed, the number of the positive electrode tabs is multiple and the positive electrode tabs are stacked together, and the number of the negative electrode tabs is multiple and the negative electrode tabs are stacked together. The material of the isolation film may be PP (polypropylene) or PE (polyethylene). In addition, the electrode assembly may have a winding structure or a lamination structure, and the embodiment of the present application is not limited thereto.

In addition, the safety of the battery needs to be considered, and lithium precipitation is one of the factors that endanger the safety of the battery.

For lithium ion batteries, lithium ions are extracted from the positive electrode and inserted into the negative electrode upon charging; during discharge, lithium ions are extracted from the negative electrode and inserted into the positive electrode. When the lithium ion battery is charged, some abnormal conditions may occur to cause lithium separation, for example, lithium ions which cannot be inserted into the negative electrode due to the abnormality that the space for inserting lithium into the negative electrode is insufficient, the migration resistance of lithium ions is too large, lithium ions are too quickly separated from the positive electrode but cannot be inserted into the negative electrode in equal amount, and the like can only obtain electrons on the surface of the negative electrode, so that a phenomenon of lithium simple substance is formed, namely, the lithium separation phenomenon.

The inventor finds that in a single battery, the wetting effect of the electrolyte on the electrode assembly is poor, so that the electrolyte is insufficient in partial area inside the electrode assembly, and lithium precipitation is caused.

In view of this, the embodiments of the present application provide a technical solution, in which a first inactive material layer region located between two first active material layer regions in a positive electrode plate is provided with a flow guiding through hole penetrating through two sides of the positive electrode plate in the thickness direction, which is beneficial to the flow of electrolyte between the electrode plates, improves the wetting effect of the electrolyte on the electrode assembly, and reduces the occurrence of a lithium separation phenomenon.

The technical scheme described in the embodiment of the application is suitable for the battery and the electric equipment using the battery.

The electric equipment can be vehicles, mobile phones, portable equipment, notebook computers, ships, spacecrafts, electric toys, electric tools and the like. The vehicle can be a fuel oil vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle or a range-extended vehicle and the like; spacecraft include aircraft, rockets, space shuttles, and spacecraft, among others; electric toys include stationary or mobile electric toys, such as game machines, electric car toys, electric ship toys, electric airplane toys, and the like; the electric power tools include metal cutting electric power tools, grinding electric power tools, assembly electric power tools, and electric power tools for railways, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, electric impact drills, concrete vibrators, and electric planers. The embodiment of the present application does not specifically limit the above-mentioned electric devices.

For convenience of explanation, the following embodiments will be described by taking an electric device as an example of a vehicle.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a vehicle 1000 according to some embodiments of the present disclosure, a battery 100 is disposed inside the vehicle 1000, and the battery 100 may be disposed at a bottom portion, a head portion, or a tail portion of the vehicle 1000. The battery 100 may be used for power supply of the vehicle 1000, for example, the battery 100 may serve as an operation power source of the vehicle 1000.

The vehicle 1000 may further include a controller 200 and a motor 300, the controller 200 being configured to control the battery 100 to supply power to the motor 300, for example, for starting, navigation, and operational power requirements while the vehicle 1000 is traveling.

In some embodiments of the present application, the battery 100 may be used not only as an operating power source of the vehicle 1000, but also as a driving power source of the vehicle 1000, instead of or in part of fuel or natural gas, to provide driving power for the vehicle 1000.

Referring to fig. 2, fig. 2 is an exploded view of a battery 100 according to some embodiments of the present disclosure, the battery 100 may include a case 10 and a battery cell 20, and the battery cell 20 is accommodated in the case 10.

The case 10 is used to accommodate the battery cells 20, and the case 10 may have various structures. In some embodiments, the case 10 may include a first portion 11 and a second portion 12, the first portion 11 and the second portion 12 cover each other, and the first portion 11 and the second portion 12 together define a receiving space 13 for receiving the battery cell 20. The second part 12 may be a hollow structure with one open end, the first part 11 is a plate-shaped structure, and the first part 11 covers the open side of the second part 12 to form the box 10 with the accommodating space 13; the first portion 11 and the second portion 12 may be hollow structures with one side open, and the open side of the first portion 11 covers the open side of the second portion 12 to form the box 10 with the accommodating space 13. Of course, the first portion 11 and the second portion 12 may be various shapes, such as a cylinder, a rectangular parallelepiped, and the like.

To improve the sealing property after the first part 11 is connected to the second part 12, a sealing member (not shown) may be disposed between the first part 11 and the second part 12, such as a sealant, a sealing ring, etc.

In the battery 100, one or more battery cells 20 may be provided. If there are a plurality of battery cells 20, the plurality of battery cells 20 may be connected in series, in parallel, or in series-parallel, where in series-parallel refers to that the plurality of battery cells 20 are connected in series or in parallel. The battery cell 20 may be cylindrical, rectangular parallelepiped, or other shape. In fig. 2, the battery cell 20 is illustratively cylindrical.

The plurality of battery cells 20 may be directly connected in series or in parallel or in series-parallel, and the whole body formed by the plurality of battery cells 20 is accommodated in the case 10. Or a plurality of battery cells 20 may be connected in series, in parallel, or in series-parallel to form a battery module, and then a plurality of battery modules may be connected in series, in parallel, or in series-parallel to form a whole, and accommodated in the case 10.

The plurality of battery cells 20 may be electrically connected to each other by a bus member (not shown) to connect the plurality of battery cells 20 in parallel or in series-parallel.

Referring to fig. 3, fig. 3 is an exploded view of the battery cell 20 shown in fig. 2. The battery cell 20 may include a case 21 and an electrode assembly 22, the electrode assembly 22 being received in the case 21.

In some embodiments, housing 21 may also be used to contain an electrolyte, such as an electrolyte. The housing 21 may take a variety of configurations.

In some embodiments, the case 21 may include a case body 211 and a cover body 212, the case body 211 having a hollow structure with one side opened, and the cover body 212 covering the opening of the case body 211 and forming a sealing connection to form a sealed space 213 for accommodating the electrode assembly 22 and the electrolyte.

When assembling the battery cell 20, the electrode assembly 22 may be first placed in the case 211, the electrolyte may be filled in the case 211, and the cover 212 may be fitted to the opening of the case 211.

The housing 211 may be various shapes such as a cylinder, a rectangular parallelepiped, etc. The shape of the case 211 may be determined according to the specific shape of the electrode assembly 22. For example, if electrode assembly 22 is of a cylindrical construction, it may optionally be a cylindrical housing; if the electrode assembly 22 has a rectangular parallelepiped structure, a rectangular parallelepiped case may be used. Of course, the cover 212 may have various structures, for example, the cover 212 has a plate-like structure, a hollow structure with one end open, and the like. Illustratively, in fig. 3, case 211 has a cylindrical structure, cover 212 has a plate-shaped structure, electrode assembly 22 has a cylindrical structure, electrode assembly 22 is accommodated in case 211, and cover 212 covers an opening at the top of case 211.

In some embodiments, the battery cell 20 may further include an electrode terminal 23, and the electrode terminal 23 is mounted on the cover 212. The electrode terminals 23 are electrically connected to the electrode assembly 22 to output electric power generated from the battery cells 20. Illustratively, the electrode terminals 23 and the electrode assembly 22 may be electrically connected by an interposer (not shown).

In some embodiments, the battery cell 20 may further include a pressure relief mechanism 24, and the pressure relief mechanism 24 is used for relieving the pressure inside the battery cell 20 when the internal pressure or temperature of the battery cell 20 reaches a predetermined value.

For example, the pressure relief mechanism 24 may be a component such as an explosion-proof valve, an explosion-proof sheet, a gas valve, a pressure relief valve, or a safety valve.

The specific structure of the electrode assembly 22 will be described in detail with reference to the accompanying drawings.

Referring to fig. 4, fig. 4 is a winding schematic diagram of the electrode assembly 22 according to some embodiments of the present disclosure, in which the electrode assembly 22 includes a positive electrode tab 221 and a negative electrode tab 222, and the positive electrode tab 221 and the negative electrode tab 222 are wound along a winding direction a to form a winding structure.

The positive electrode tab 221 and the negative electrode tab 222 are stacked in the thickness direction of the positive electrode tab 221. The winding direction a is a direction in which the positive electrode tab 221 and the negative electrode tab 222 are wound in the circumferential direction from inside to outside.

The winding structure can be a cylinder or a flat body. In fig. 4, the coiled structure is illustratively cylindrical.

In some embodiments, the positive electrode sheet 221 includes a positive electrode collector 2211 (not shown in fig. 4) and a positive electrode active material layer 2212 (not shown in fig. 4) coated on both sides of the positive electrode collector 2211 in the thickness direction. The negative electrode tab 222 includes a negative electrode collector 2221 (not shown in fig. 4) and a negative electrode active material layer 2222 (not shown in fig. 4) coated on both sides in the thickness direction of the negative electrode collector 2221.

In some embodiments, the electrode assembly 22 may further include a separator 223, and the separator 223 is used to separate the positive electrode pole piece 221 and the negative electrode pole piece 222 to reduce the risk of short circuit between the positive electrode pole piece 221 and the negative electrode pole piece 222.

The isolation film 223 has a large number of through micropores, which can ensure that electrolyte ions can pass through freely and has good penetrability on lithium ions. The material of the isolation film 223 may be PP (polypropylene) or PE (polyethylene).

In the case where the separator 223 is included in the electrode assembly 22, the positive electrode tab 221, the separator 223, and the negative electrode tab 222 may be stacked together and then the whole may be wound in the winding direction a to form a wound structure.

In some embodiments, the positive electrode tab 221 includes a plurality of first active material layer regions 2213 and at least one first inactive material layer region 2214, and the first inactive material layer region 2214 is located between two adjacent first active material layer regions 2213 in the axial direction B of the winding structure. The first inactive material layer region 2214 is provided with a first flow guiding through hole 2215, and the first flow guiding through hole 2215 is arranged to penetrate through both sides in the thickness direction of the positive electrode tab 221. The axial direction B of the wound structure referred to herein is the arrangement direction of the axis of the wound structure, and may also be understood as the width direction of the positive electrode sheet 221.

In the above structure, since the first inactive material layer region 2214 is provided on the positive electrode tab 221, the number of lithium ions released from the positive electrode tab 221 during charging can be reduced, and the occurrence of a lithium deposition phenomenon can be reduced. Since the first inactive material layer region 2214 is provided with the first flow guiding through holes 2215 penetrating through the two sides of the positive electrode sheet 221 in the thickness direction, the electrolyte can flow between the electrode sheets, the infiltration effect of the electrolyte on the electrode assembly 22 is improved, and the occurrence of a lithium precipitation phenomenon is reduced.

In the electrode assembly 22, the electrolyte generally enters the electrode assembly 22 from both ends in the axial direction B of the wound structure, but since the gaps between the pole pieces may be irregular, some gaps are large and some gaps are small; if the gap between the pole pieces is small, the electrolyte is difficult to infiltrate the pole pieces. Since the first inactive material layer 2214 of the positive electrode plate 221 is provided with the first flow guide through hole 2215, the electrolyte can flow between the electrode plates, and after the electrolyte enters the large gap between the electrode plates from the two ends of the axial direction B of the winding structure, the electrolyte can enter the small gap between the electrode plates through the first flow guide through hole 2215 to infiltrate the electrode plates and reduce lithium precipitation.

Taking any three circles of pole pieces in the winding structure as an example, the three circles of pole pieces are respectively a first circle of pole piece, a second circle of pole piece and a third circle of pole piece, the first circle of pole piece, the second circle of pole piece and the third circle of pole piece are sequentially arranged from inside to outside, the first circle of pole piece and the third circle of pole piece are negative pole pieces 222, the second circle of pole piece is positive pole pieces 221, the gap between the first circle of pole piece and the second circle of pole piece is relatively small, and the gap between the second circle of pole piece and the third circle of pole piece is relatively large. Because the clearance between the first circle of pole pieces and the second circle of pole pieces is relatively small, the electrolyte is difficult to enter into between the first circle of pole pieces and the second circle of pole pieces from the two ends of the axial B of the winding structure, but the electrolyte can enter into between the second circle of pole pieces and the third circle of pole pieces from the two ends of the axial B of the winding structure, and then enters into between the first circle of pole pieces and the second circle of pole pieces through the first flow guide through hole 2215 on the second circle of pole pieces, so that the effect of soaking the electrolyte is improved.

It should be noted that the first active material layer area 2213 of the positive electrode plate 221 is a portion of the positive electrode plate 221 where the positive active material layer 2212 is disposed, and the first inactive material layer area 2214 of the positive electrode plate 221 is a portion of the positive electrode plate 221 where the positive active material layer 2212 is not disposed, that is, the thickness of the portion of the positive electrode plate 221 located in the first active material layer area 2213 is greater than the thickness of the portion of the positive electrode plate 221 located in the first inactive material layer area 2214, so that the distance between the portion of the positive electrode plate 221 located in the first inactive material layer area 2214 and the negative electrode plate 222 is increased, and the electrolyte can conveniently enter the first flow guiding through hole 2215.

The first active material layer region 2213 in the positive electrode sheet 221 may be two, three, or the like that are spaced apart in the axial direction B of the wound structure. In fig. 4, two first active material layer regions 2213 in the positive electrode sheet 221 are exemplarily provided, and one first inactive material layer region 2214 is provided between the two first active material layer regions 2213.

Referring to fig. 5, fig. 5 is a cross-sectional view of the positive electrode sheet 221 according to some embodiments of the present application, since the first inactive material layer 2214 of the positive electrode sheet 221 is not provided with the positive active material layer 2212, and the first flow guiding through hole 2215 penetrates through two sides of the positive electrode sheet 221 in the thickness direction, it can be understood that the first flow guiding through hole 2215 penetrates through two sides of the positive electrode current collector 2211 of the positive electrode sheet 221 in the thickness direction.

The first flow passage 2215 may have various shapes, such as a circle, an ellipse, a rectangle, a trapezoid, etc.

In the positive electrode plate 221, there may be one or more first flow guide through holes 2215, and the specific number of the first flow guide through holes 2215 may be set according to specific requirements.

In some embodiments, the first inactive material layer area 2214 is provided with a plurality of first flow guide through holes 2215 spaced apart in the winding direction a (see fig. 4). Electrolyte can flow between the pole pieces through the first flow guide through holes 2215, and the infiltration effect of the electrolyte on the electrode assembly 22 is further improved.

Referring to fig. 6, fig. 6 is a schematic structural diagram of the expanded positive electrode sheet 221 according to some embodiments of the present application, in which the positive electrode sheet 221 has two ends, which are a first winding start end 2216 and a first winding end 2217 respectively. After the positive electrode sheet 221 is wound, the first winding start end 2216 is closer to the center of the winding structure than the first winding end 2217. The first flow guiding through holes 2215 are spaced in the first inactive material layer area 2214 along the winding direction a (see fig. 4), and it can be understood that when the positive electrode plate 221 is unfolded (the positive electrode plate 221 is in a flat state), the first flow guiding through holes 2215 are spaced in the first inactive material layer area 2214 along the direction from the first winding start end 2216 of the positive electrode plate 221 to the first winding tail end 2217.

In some embodiments, with continued reference to fig. 6, in the winding direction a (see fig. 4), the distance between every two adjacent first flow guiding through holes 2215 gradually increases. It can be understood that, when the positive electrode sheet 221 is unfolded, the distance between every two adjacent first guiding through holes 2215 gradually increases in the direction that the first winding start end 2216 of the positive electrode sheet 221 points to the first winding tail end 2217.

In other embodiments, referring to fig. 7, fig. 7 is a schematic structural view of the cathode plate 221 provided in other embodiments of the present application after being unfolded, and in the winding direction a, the distance between every two adjacent first flow guiding through holes 2215 is equal. It can be understood that, when the positive electrode sheet 221 is unfolded, in a direction in which the first winding start end 2216 of the positive electrode sheet 221 points to the first winding end 2217, the distance between every two adjacent first flow guiding through holes 2215 is equal, that is, the first flow guiding through holes 2215 are uniformly distributed on the positive electrode sheet 221.

In some embodiments, referring to fig. 8, fig. 8 is a diagram illustrating a positional relationship among the positive electrode tab 221, the separator 223, and the negative electrode tab 222 according to some embodiments of the present disclosure; the negative electrode tab 222 may be provided with a second flow guide through hole 2223, and the second flow guide through hole 2223 may be disposed to penetrate through both sides of the negative electrode tab 222 in the thickness direction. That is, the electrolyte can flow between the positive electrode plate 221 through the first flow guiding through hole 2215, and can also flow between the negative electrode plate 222 through the second flow guiding through hole 2223, so as to further improve the wetting effect of the electrolyte on the electrode assembly 22.

The second guide through hole 2223 may have various shapes, for example, a circular shape, an oval shape, a rectangular shape, a trapezoidal shape, etc. The size of the second guiding through hole 2223 may be equal to or different from the size of the first guiding through hole 2215.

In some embodiments, with continued reference to fig. 8, the negative electrode tab 222 includes a second active material layer area 2224, the second flow guide through hole 2223 is disposed in the second active material layer area 2224, and the first active material layer area 2213 and the first inactive material layer area 2214 of the positive electrode tab 221 are both disposed opposite the second active material layer area 2224.

The second active material layer region 2224 is a portion of the negative electrode tab 222 where the negative electrode active material layer 2222 is provided. That is, the portions of the negative electrode sheet 222 opposite the first active material layer region 2213 and the first inactive material layer region 2214 each have the negative electrode active material layer 2222, increasing the bending resistance of the electrode assembly 22 in the region of the first inactive material layer region 2214.

The second flow guiding through hole 2223 penetrates the negative electrode collector 2221 and the negative electrode active material layer 2222 of the negative electrode sheet 222.

In some embodiments, referring to fig. 9, fig. 9 provides a positional relationship diagram of the positive electrode sheet 221, the separator 223 and the negative electrode sheet 222 according to still other embodiments of the present disclosure, where the negative electrode sheet 222 includes a plurality of second active material layer regions 2224 and at least one second inactive material layer region 2225, in the axial direction B of the winding structure, the second inactive material layer region 2225 is located between two adjacent second active material layer regions 2224, and the second flow guiding through hole 2223 is disposed in the second inactive material layer region 2225.

Wherein the second active material layer region 2224 is disposed opposite the first active material layer region 2213, the second inactive material layer region 2225 is disposed opposite the first inactive material layer region 2214, and the width of the second inactive material layer region 2225 in the axial direction B of the wound structure does not exceed the width of the first inactive material layer region 2214 in the axial direction B of the wound structure.

The second inactive material layer area 2225 is arranged on the negative electrode sheet 222, that is, the negative electrode sheet 222 is not provided with the negative active material layer 2222 in the area, so that the production cost can be effectively reduced, and the economy is better. Since the first active material layer region 2213 is arranged opposite to the second active material layer region 2224, the first inactive material layer region 2214 is arranged opposite to the second inactive material layer region 2225, and the width of the second inactive material layer region 2225 in the axial direction B of the winding structure is not more than the width of the first inactive material layer region 2214 in the axial direction B of the winding structure, lithium ions which are separated from the positive electrode sheet 221 and inserted into the negative electrode sheet 222 during charging are ensured, and lithium ions which are separated from the negative electrode sheet 222 and inserted into the positive electrode sheet 221 in equal amount during discharging can be separated from the negative electrode sheet 222 and inserted into the positive electrode sheet 221, so that the occurrence of a lithium precipitation phenomenon is reduced.

Illustratively, in fig. 9, the width of the second inactive material layer region 2225 in the axial direction B of the wound structure is less than the width of the first inactive material layer region 2214 in the axial direction B of the wound structure.

The second active material layer area 2224 of the negative electrode sheet 222 is a portion of the negative electrode sheet 222 where the negative electrode active material layer 2222 is disposed, and the second inactive material layer area 2225 of the negative electrode sheet 222 is a portion of the negative electrode sheet 222 where the negative electrode active material layer 2222 is not disposed, that is, the thickness of the portion of the negative electrode sheet 222 located in the second active material layer area 2224 is greater than the thickness of the portion of the negative electrode sheet 222 located in the second inactive material layer area 2225, so that the distance between the portion of the negative electrode sheet 222 located in the second inactive material layer area 2225 and the portion of the positive electrode sheet 221 located in the first inactive material layer area 2214 is increased, and the electrolyte can conveniently enter the second flow guide through hole 2223.

In the axial direction B of the wound structure, the second active material layer areas 2224 in the negative electrode sheet 222 may be two, three, or the like that are distributed at intervals, and the second active material layer areas 2224 in the negative electrode sheet 222 may correspond one-to-one to the first active material layer areas 2213 in the positive electrode sheet 221. In fig. 9, for example, two first active material layer regions 2213 in the positive electrode sheet 221, and one first inactive material layer region 2214 is disposed between the two first active material layer regions 2213; there are also two second active material layer regions 2224 in the negative electrode tab 222, and one second inactive material layer region 2225 is provided between the two second active material layer regions 2224.

In the present embodiment, since the negative active material layer 2222 is not disposed in the second inactive material layer region 2225 of the negative electrode sheet 222, the second flow guiding through holes 2223 penetrate both sides of the negative electrode sheet 222 in the thickness direction, and it can be understood that the second flow guiding through holes 2223 penetrate both sides of the negative electrode collector 2221 of the negative electrode sheet 222 in the thickness direction.

In the negative electrode sheet 222, there may be one or more second flow guide through holes 2223, and the specific number of the second flow guide through holes 2223 may be set according to specific requirements.

In some embodiments, the negative electrode sheet 222 is provided with a plurality of second flow guiding through holes 2223 spaced apart along the winding direction a (see fig. 4). The electrolyte can flow between the pole pieces through the second plurality of flow guide through holes 2223, further improving the wetting effect of the electrolyte on the electrode assembly 22.

Referring to fig. 10, fig. 10 is a schematic structural diagram of the cathode pole piece 222 after being unfolded according to some embodiments of the present application, in which the cathode pole piece 222 has two ends, namely a second winding start end 2226 and a second winding end 2227. After the negative electrode sheet 222 is wound, the second winding start end 2226 is closer to the center of the wound structure than the second winding end 2227. The second flow guiding through holes 2223 are spaced from the negative electrode plate 222 along the winding direction a (see fig. 4), and it can be understood that when the negative electrode plate 222 is unfolded (the negative electrode plate 222 is in a flat state), the second flow guiding through holes 2223 are spaced from the negative electrode plate 222 along a direction in which the second winding start end 2226 of the negative electrode plate 222 points to the second winding end 2227.

In some embodiments, with continued reference to fig. 10, in the winding direction a (see fig. 4), the distance between every two adjacent second flow guiding through holes 2223 gradually increases. It can be understood that, when the negative electrode sheet 222 is unfolded, the distance between every two adjacent second flow guiding through holes 2223 gradually increases in the direction that the second winding start end 2226 of the negative electrode sheet 222 points to the second winding end 2227.

In other embodiments, referring to fig. 11, fig. 11 is a schematic structural view of the negative electrode sheet 222 provided in other embodiments of the present application after being unfolded, and in the winding direction a, the distance between every two adjacent second flow guiding through holes 2223 is equal. It can be understood that when the negative electrode sheet 222 is unfolded, in a direction in which the second winding start end 2226 of the negative electrode sheet 222 points to the second winding end 2227, the distance between every two adjacent second flow guide through holes 2223 is equal, that is, the second flow guide through holes 2223 are uniformly distributed on the negative electrode sheet 222.

It should be noted that, in the embodiment of the present application, whether the second active material layer area 2224 is disposed on the negative electrode sheet 222 or not, the second flow guiding through holes 2223 on the negative electrode sheet 222 all adopt the above-mentioned pitch arrangement manner or the pitch variation arrangement manner.

In some embodiments, referring to fig. 12, fig. 12 is a schematic structural view of an electrode assembly 22 provided in some embodiments of the present disclosure, a flow guide passage 224 allowing an electrolyte to flow from an outside of the wound structure to an inside of the wound structure is disposed on the wound structure, and the flow guide passage 224 is formed by a plurality of first flow guide through holes 2215 and a plurality of second flow guide through holes 2223. Electrolyte outside the winding structure can enter the inside of the winding structure through the flow guide channels 224, and meanwhile, gas generated inside the electrode assembly 22 can be discharged through the electrode assembly 22, so that the exhaust effect of the electrode assembly 22 and the wetting effect of the electrolyte on the electrode assembly 22 are improved.

The outer end of the flow guide channel 224 penetrates through the outermost pole piece in the winding structure. If the outermost pole piece in the winding structure is the positive pole piece 221, a first flow guide through hole 2215 is formed in the outermost pole piece in the winding structure, and the first flow guide through hole 2215 is a part of the flow guide channel 224; if the outermost pole piece in the winding structure is the negative pole piece 222, a second flow guiding through hole 2223 is formed in the outermost pole piece in the winding structure, and the second flow guiding through hole 2223 is a part of the flow guiding channel 224. Illustratively, in fig. 12, the outermost pole piece in the wound structure is the negative pole piece 222.

Under the condition that a central hole 225 extending along the axial direction B of the winding structure is formed in the winding structure, the flow guide channel 224 can be communicated with the central hole 225, namely, the inner end of the flow guide channel 224 penetrates through the innermost pole piece in the winding structure, so that the electrolyte can infiltrate into the innermost pole piece, and the gas in the central hole 225 can be conveniently discharged.

Of course, the flow guiding channel 224 may not be communicated with the central hole 225, for example, only the outermost turns of the positive electrode sheet 221 of the winding structure are provided with the first flow guiding through holes 2215, and only the outermost turns of the negative electrode sheet 222 of the winding structure are provided with the second flow guiding through holes 2223, so that the flow guiding channel 224 formed by the first flow guiding through holes 2215 and the second flow guiding through holes 2223 does not extend into the innermost turns of the positive electrode sheet of the winding structure.

In the flow guide passage 224, the shape of the first flow guide through hole 2215 may be the same as or different from that of the second flow guide through hole 2223. The size of the first flow guiding through hole 2215 and the size of the second flow guiding through hole 2223 may be equal or different. For example, in fig. 12, the first flow guiding through hole 2215 and the second flow guiding through hole 2223 are both circular, and the diameter of the first flow guiding through hole 2215 is equal to that of the second flow guiding through hole 2223.

One or more flow guide channels 224 may be provided in the winding structure, and the specific number of the flow guide channels 224 may be set according to specific requirements.

In some embodiments, the winding structure is provided with a plurality of flow guide channels 224 spaced along the winding direction a, i.e. the plurality of flow guide channels 224 are spaced along the circumference of the winding structure.

Electrolyte outside the winding structure can enter the electrode assembly 22 from different directions through the plurality of flow guide channels 224, and gas generated inside the electrode assembly 22 can be discharged from different directions through the plurality of flow guide channels 224, so that the exhaust effect of the electrode assembly 22 and the wetting effect of the electrolyte on the electrode assembly 22 are further improved.

Illustratively, electrode assembly 22 is a wound structure having a cylindrical shape.

In some embodiments, the flow guide channels 224 extend along a straight line, and the flow guide channels 224 extend in a non-zero angle with respect to the axial direction B of the winding structure. The structure improves the smoothness of the electrolyte and the gas flowing in the flow guide channel 224, and facilitates the infiltration of the electrolyte and the discharge of the gas.

The guide passages 224 extend in a straight line, that is, each first guide through hole 2215 and each second guide through hole 2223 in the guide passages 224 are located on the same straight line. In other embodiments, the flow guide channel 224 may extend in a non-straight line, for example, the flow guide channel 224 extends along an S-shaped line, a spiral line, etc.

In this embodiment, in the winding direction a, the distance between every two adjacent first flow guiding through holes 2215 in the positive electrode sheet 221 may gradually increase, and the distance between every two adjacent second flow guiding through holes 2223 in the negative electrode sheet 222 may also gradually increase.

Optionally, the flow guide channel 224 extends in a direction perpendicular to the axial direction B (see fig. 4) of the winding structure. The structure can shorten the flow path of the electrolyte and the gas, and can effectively improve the infiltration efficiency and the gas discharge efficiency of the electrolyte.

It should be noted that, as shown in fig. 12, the flow guide passages 224 in the winding structure may extend along a straight line, such that the first flow guide through hole 2215 is aligned with the adjacent second flow guide through hole 2223. In another embodiment, referring to fig. 13, fig. 13 is a schematic structural view of an electrode assembly 22 provided in another embodiment of the present application, in the flow guide passage 224, the first flow guide through hole 2215 may be staggered from the second flow guide through hole 2223 adjacent to the first flow guide through hole 2215, and the staggered first flow guide through hole 2215 and the second flow guide through hole 2223 are communicated through a gap between two adjacent circles of pole pieces.

In some embodiments, referring to fig. 14, fig. 14 is a schematic structural view of an electrode assembly 22 according to other embodiments of the present disclosure, in which the flow guide passage 224 includes a plurality of flow guide through holes spaced apart along an extending direction thereof, and the plurality of flow guide through holes include a plurality of first flow guide through holes 2215 and a plurality of second flow guide through holes 2223, that is, a part of the flow guide through holes in the plurality of flow guide passages 224 are first flow guide through holes 2215, and a part of the flow guide through holes are second flow guide through holes 2223. The aperture of each flow guide through hole in the flow guide passage 224 is gradually reduced in a direction in which the flow guide passage 224 extends toward the inside of the winding structure.

In the winding structure, the circumference of each circle of pole piece is gradually increased from the innermost circle of pole pieces to the outermost circle of pole pieces, and the infiltration requirement on electrolyte is also gradually increased. In the extending direction of the flow guide channel 224 to the inside of the winding structure, the aperture of each flow guide through hole in the flow guide channel 224 is gradually reduced, so that on one hand, the requirements that the inner ring pole piece has small infiltration requirement on electrolyte and the outer ring pole piece has large infiltration requirement on electrolyte can be met.

In the present embodiment, in the direction in which the flow guide channel 224 extends toward the inside of the winding structure, the aperture of each flow guide through hole in the flow guide channel 224 gradually decreases, so that the entire flow guide channel 224 is a tapered structure with a large outer end and a small inner end. Wherein the inner end of the flow guide channel 224 is closer to the center of the winding structure than the outer end.

In some embodiments, please refer to fig. 15, and fig. 15 is a schematic structural diagram of an electrode assembly 22 according to still other embodiments of the present disclosure. The winding structure includes an outer ring portion 226 and an inner ring portion 227 concentrically arranged, and the inner ring portion 227 is located inside the outer ring portion 226. A first flow through hole 2215 is provided in the positive pole piece 221 in the outer ring portion 226, a second flow through hole 2223 is provided in the negative pole piece 222 in the outer ring portion 226, and a flow channel 224 is formed in the outer ring portion 226.

Electrolyte can enter the interior of the wound structure through the flow channels 224 to wet the pole pieces in the outer rim 226. The first flow guide through hole 2215 and the second flow guide through hole 2223 are respectively arranged on the positive pole piece 221 and the negative pole piece 222 in the outer ring part 226, the first flow guide through hole 2215 is not arranged on the positive pole piece 221 in the inner ring part 227, and the second flow guide through hole 2223 is not arranged on the negative pole piece 222 in the inner ring part 227, namely, the pole pieces in the inner ring part 227 are not perforated, so that the production cost can be effectively reduced, and the economical efficiency is better.

Illustratively, the number of turns of the pole pieces in the inner loop portion 227 is less than the number of turns of the pole pieces in the outer loop portion 226. The number of turns of the pole pieces in the inner ring portion 227 may be 1-5 turns. The first flow through hole 2215 on the positive pole piece 221 in the outer ring portion 226 has an equal aperture to the second flow through hole 2223 on the negative pole piece 222 in the outer ring portion 226.

The aperture of the first flow guide through hole 2215 in the outer ring portion 226 and the aperture of the second flow guide through hole 2223 may be larger than the diameter of the outermost pole piece in the inner ring portion 227, or may be smaller than the diameter of the outermost pole piece in the inner ring portion 227.

In some embodiments, referring to fig. 16, fig. 16 is a schematic structural diagram of an electrode assembly 22 according to still other embodiments of the present disclosure, in which a winding structure includes an outer ring portion 226 and an inner ring portion 227 concentrically arranged, and the inner ring portion 227 is located inside the outer ring portion 226. The positive electrode pole piece 221 in the outer ring portion 226 and the inner ring portion 227 are provided with a first flow guiding through hole 2215, the negative electrode pole piece 222 in the outer ring portion 226 and the inner ring portion 227 are provided with a second flow guiding through hole 2223, and flow guiding channels 224 are formed in the outer ring portion 226 and the inner ring portion 227. The first flow passage 2215 in the inner ring portion 227 has a smaller diameter than the first flow passage 2215 in the outer ring portion 226, and the second flow passage 2223 in the inner ring portion 227 has a smaller diameter than the second flow passage 2223 in the outer ring portion 226. This arrangement allows the flow directing through holes in the pole pieces in the outer ring 226 to be relatively large in diameter and the flow directing through holes in the pole pieces in the inner ring 227 to be relatively small. The aperture of the flow guide through holes on the pole pieces in the outer ring portion 226 is relatively large, so that the electrolyte outside the wound structure can rapidly enter the electrode assembly 22 through the flow guide through holes on the pole pieces in the outer ring portion 226; the flow guide through holes in the pole pieces in the inner ring portion 227 are relatively small, and the flow guide through holes are conveniently formed in the pole pieces in the inner ring portion 227.

Illustratively, the number of turns of the pole pieces in the inner loop portion 227 is less than the number of turns of the pole pieces in the outer loop portion 226. The number of turns of the pole pieces in the inner ring portion 227 may be 1-5 turns. The first flow through hole 2215 on the positive pole piece 221 in the outer ring portion 226 has an equal aperture to the second flow through hole 2223 on the negative pole piece 222 in the outer ring portion 226. The first flow through hole 2215 on the positive pole piece 221 in the inner ring portion 227 has the same aperture as the second flow through hole 2223 on the negative pole piece 222 in the inner ring portion 227.

Referring to fig. 17, fig. 17 is a flowchart illustrating a method of manufacturing an electrode assembly 22 according to some embodiments of the present disclosure, where the method of manufacturing the electrode assembly 22 includes:

s100: providing a positive pole piece 221 and a negative pole piece 222;

s200: winding the negative electrode sheet 222 and the positive electrode sheet 221 in a winding direction a to form a winding structure;

the positive electrode plate 221 includes a plurality of first active material layer regions 2213 and at least one first inactive material layer region 2214, and the first inactive material layer region 2214 is located between two adjacent first active material layer regions 2213 in the axial direction B of the winding structure. The first inactive material layer region 2214 is provided with a first flow guiding through hole 2215, and the first flow guiding through hole 2215 is arranged to penetrate through both sides in the thickness direction of the positive electrode tab 221.

In some embodiments, a separator 223 for separating the positive electrode pole piece 221 and the negative electrode pole piece 222 is further provided, and the positive electrode pole piece 221, the separator 223, and the negative electrode pole piece 222 are wound in the winding direction a and form a wound structure.

It should be noted that, regarding the structure of the electrode assembly 22 manufactured by the above manufacturing method, reference may be made to the electrode assembly 22 provided in each of the above embodiments.

Referring to fig. 18, fig. 18 is a schematic block diagram of a manufacturing apparatus 2000 for an electrode assembly 22 according to some embodiments of the present application, where the manufacturing apparatus 2000 includes a providing device 1100 and an assembling device 1200, the providing device 1100 is used for providing a positive electrode tab 221 and a negative electrode tab 222, and the assembling device 1200 is used for winding the negative electrode tab 222 and the positive electrode tab 221 along a winding direction a and forming a winding structure.

In some embodiments, the provision apparatus 1100 is also used to provide a separator 223 separating the positive pole piece 221 and the negative pole piece 222. The assembly apparatus 1200 is used to wind the positive electrode tab 221, the separator 223, and the negative electrode tab 222 in the winding direction a and form a wound structure.

It should be noted that, regarding the structure of the electrode assembly 22 manufactured by the manufacturing apparatus 2000, reference may be made to the electrode assembly 22 provided in each of the above embodiments.

The above embodiments are merely for illustrating the technical solutions of the present application and are not intended to limit the present application, and those skilled in the art can make various modifications and variations of the present application. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An electrode assembly, comprising a positive electrode sheet and a negative electrode sheet wound in a winding direction to form a wound structure;

the positive pole piece comprises a plurality of first active material layer regions and at least one first inactive material layer region, the first inactive material layer regions are positioned between two adjacent first active material layer regions in the axial direction of the winding structure, the first inactive material layer regions are provided with first flow guide through holes, and the first flow guide through holes are configured to penetrate through two sides of the positive pole piece in the thickness direction;

the negative pole piece is provided with a second flow guide through hole which is configured to penetrate through two sides of the negative pole piece in the thickness direction;

the winding structure is provided with a flow guide channel for allowing electrolyte to flow from the outside of the winding structure to the inside of the winding structure; the plurality of first flow guide through holes and the plurality of second flow guide through holes form the flow guide channel.

2. The electrode assembly of claim 1, wherein the first inactive material layer region is provided with a plurality of the first current guiding through holes spaced apart in the winding direction.

3. The electrode assembly according to claim 2, wherein the pitch of each adjacent two first flow guide through holes is gradually increased in the winding direction; or in the winding direction, the distance between every two adjacent first flow guide through holes is equal.

4. The electrode assembly of claim 3, wherein the negative electrode tab includes a second active material layer region, the second current guiding through hole is disposed in the second active material layer region, and the first active material layer region and the first inactive material layer region are both disposed opposite to the second active material layer region.

5. The electrode assembly of claim 3, wherein the negative electrode tab comprises a plurality of second active material layer regions and at least one second inactive material layer region, the second inactive material layer regions being located between two adjacent second active material layer regions in the axial direction, the second current guiding through-hole being provided in the second inactive material layer regions;

wherein the second active material layer region is disposed opposite the first active material layer region, the second inactive material layer region is disposed opposite the first inactive material layer region, and a width of the second inactive material layer region in the axial direction does not exceed a width of the first inactive material layer region in the axial direction.

6. The electrode assembly of claim 3, wherein the negative electrode tab is provided with a plurality of second flow guide through holes spaced apart in the winding direction.

7. The electrode assembly according to claim 6, wherein the pitch of each adjacent two second flow guide through holes is gradually increased in the winding direction; or in the winding direction, the distance between every two adjacent second flow guide through holes is equal.

8. The electrode assembly of claim 1, wherein the winding structure is provided with a plurality of the flow guide channels spaced apart in the winding direction.

9. The electrode assembly of claim 1, wherein the flow guide channel extends along a straight line, and the flow guide channel extends in a non-zero angle with respect to the axial direction.

10. The electrode assembly of claim 9, wherein the direction of extension is perpendicular to the axial direction.

11. The electrode assembly of claim 1, wherein the flow guide channel includes a plurality of flow guide through holes spaced apart along an extending direction thereof, the plurality of flow guide through holes including a plurality of the first flow guide through holes and a plurality of the second flow guide through holes;

in the direction that the flow guide channel extends towards the inside of the winding structure, the aperture of each flow guide through hole in the flow guide channel is gradually reduced; or the apertures of all the flow guide through holes in the flow guide channel are equal.

12. The electrode assembly of claim 1, wherein the winding structure comprises an outer coil portion and an inner coil portion concentrically arranged, the inner coil portion being located inside the outer coil portion;

the first flow guide through hole is formed in the positive pole piece in the outer ring portion, the second flow guide through hole is formed in the negative pole piece in the outer ring portion, and the flow guide channel is formed in the outer ring portion.

13. The electrode assembly of claim 1, wherein the winding structure comprises an outer coil portion and an inner coil portion concentrically arranged, the inner coil portion being located inside the outer coil portion;

the positive pole pieces in the outer ring part and the inner ring part are provided with the first flow guide through holes, the negative pole pieces in the outer ring part and the inner ring part are provided with the second flow guide through holes, and the flow guide channels are formed in the outer ring part and the inner ring part;

the aperture of the first flow guide through hole in the inner ring part is smaller than that of the first flow guide through hole in the outer ring part, and the aperture of the second flow guide through hole in the inner ring part is smaller than that of the second flow guide through hole in the outer ring part.

14. The electrode assembly of claim 1, wherein the interior of the winding structure is formed with a central hole extending in the axial direction, and the flow guide passage communicates with the central hole.

15. A battery cell comprising a housing and an electrode assembly according to any one of claims 1-14;

the electrode assembly is received in the case.

16. A battery comprising a case and the battery cell of claim 15;

the battery unit is accommodated in the box body.

17. An electric device characterized by comprising the battery according to claim 16.

18. A method of manufacturing an electrode assembly, comprising:

providing a positive pole piece and a negative pole piece;

winding the negative pole piece and the positive pole piece along a winding direction to form a winding structure;

the positive pole piece comprises a plurality of first active material layer regions and at least one first inactive material layer region, the first inactive material layer regions are located between two adjacent first active material layer regions in the axial direction of the winding structure, the first inactive material layer regions are provided with first flow guide through holes, and the first flow guide through holes are configured to penetrate through two sides of the positive pole piece in the thickness direction;

the winding structure is provided with a flow guide channel for allowing the electrolyte to flow from the outside of the winding structure to the inside of the winding structure; the plurality of first flow guide through holes and the plurality of second flow guide through holes form the flow guide channel.

19. An apparatus for manufacturing an electrode assembly, comprising:

the device comprises a providing device, a control device and a control device, wherein the providing device is used for providing a positive pole piece and a negative pole piece; and

the assembling device is used for winding the negative pole piece and the positive pole piece along the winding direction and forming a winding structure;