Patent Description:
Owing to such advantages as small size, high energy density, high power density, multiple cycles and long storage time, lithium ion batteries are widely used in some electronic equipment, electric transportation tools, electric toys and electric devices, for example, lithium ion batteries have been widely used in mobile phones, notebook computers, battery cars, electric vehicles, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes and electric tools. <CIT> relates to a multi-pole-piece winding-type cell which comprise a plurality of anode sheets, a plurality of cathode sheets and a plurality of diaphragms. The multi-pole-piece winding-type cell comprises the plurality of anode sheets and the plurality of cathode sheets, wherein the anode sheets and the cathode sheets are wound to form the winding body. <CIT> relates to an energy storage device. An energy storage device includes: a first electrode sheet; and a second electrode sheet stacked on the first electrode sheet with a separator interposed between the first electrode sheet and the second electrode sheet and having a polarity different from a polarity of the first electrode sheet. <CIT> relates to a battery, A battery includes a flat wound electrode body that is obtained by winding a first electrode sheet and a second electrode sheet in a flat shape via separator sheets. <CIT> relates to a nonaqueous electrolyte battery in which a winding body is uniformly expanded, to thereby prevent undulation. A nonaqueous electrolyte battery comprises a winding body having a flattened shape, in which a positive electrode and a negative electrode are wound with separators interposed therebetween, and a negative electrode tab joined to the negative electrode, extending in a winding axis direction of the winding body. The positive electrode includes a positive electrode current collector having a strip-like shape, a first positive electrode mixture layer formed on one surface of the positive electrode current collector, and a second positive electrode mixture layer formed on the other surface of the positive electrode current collector, and a winding trailing end portion of the first positive electrode mixture layer is positioned on an inner side of the winding body with respect to the negative electrode tab in the width direction and a winding trailing end portion of the second positive electrode mixture layer is positioned on an outer side of the winding body with respect to the negative electrode tab in the width direction.

The electrode assembly is an important unit of the lithium ion battery, and the winding electrode assembly has been widely used in lithium ion batteries owing to its characteristics of simple production process and high production efficiency.

However, to improve the volumetric energy density of the lithium ion battery, the electrode assembly generally needs to be wound for a plurality of turns, when the electrode assembly is wound for a plurality of times, and a tab is easily misplaced seriously, thereby influencing the connection with the collector component.

An object of the present disclosure is to provide an electrode assembly and a related battery, device, manufacturing method and manufacturing device thereof, to improve the problem of misplacement of the tab caused by winding for a plurality of times.

According to a first aspect of the invention an electrode assembly is provided according to claim <NUM>.

In some embodiments, each first electrode plate comprises a plurality of first tabs which are arranged at intervals.

In some embodiments, in the winding structure, each first electrode plate is provided with at least one tab on each of its circles.

In some embodiments, any two first tabs in all the first tabs are at least partially overlapped.

In some embodiments, the winding structure is flat and comprises a straight section and turning sections arranged on two sides of the straight section; and all the first tabs are arranged in the straight section.

In some embodiments, the straight section comprises a first straight sub-section and a second straight sub-section which are substantially parallel and distributed symmetrically about the winding axis;.

In some embodiments, the positions of the winding tail ends of at least two first electrode plates in the plurality of first electrode plates are different.

In some embodiments, the electrode assembly comprises a plurality of second electrode plates, wherein the positions of the winding initial ends of at least two second electrode plates in the plurality of second electrode plates are different; and/or, the positions of the winding tail ends of at least two second electrode plates in the plurality of second electrode plates are different.

In some embodiments, the electrode assembly comprises a plurality of second electrode plates, and the winding structure is flat and comprises a straight section and turning sections arranged at two sides of the straight section; and wherein the winding tail end of at least one first electrode plate in the plurality of first electrode plates are arranged in the turning section; and/or the winding tail end of at least one second electrode plate in the plurality of second electrode plates are arranged in the turning section.

In some embodiments, in different radial directions of the winding structure, the difference of number of layers of the first electrode plate and the second electrode plate does not exceed a preset number of layers.

A second aspect of the invention provides a battery, comprising:.

A third aspect of the invention provides a battery module, comprising: a plurality of batteries provided in the second aspect of the invention.

A fourth aspect of the invention provides a battery pack, comprising: a plurality of battery modules provided in the third aspect of the invention.

A fifth aspect of the invention provides a device using the battery, comprising the battery provided in the second aspect of the invention, wherein the battery is configured to provide electric energy.

A sixth aspect of the invention provides a manufacturing method of the electrode assembly according to claim <NUM>.

A seventh aspect of the invention provides a manufacturing device of an electrode assembly according to claim <NUM>.

Based on the technical solution provided in the present disclosure, the electrode assembly comprises a plurality of first electrode plates, and the length of the first electrode plate is equivalent to be shortened, and further the number of winding turns of the electrode assembly is reduced, then the amount of misplacement of the first tab on the circumferential direction after winding can be reduced, and connection with the collector component is facilitated. Moreover, the first tab and the first main body portion of the present disclosure are distributed in parallel along the winding axis, thereby enlarging the area, coated with the first active substance layer, on the first current collector, and further improving energy density of the electrode assembly.

Other characteristics and advantages of the present disclosure will become clear through a detailed description of exemplary embodiments of the present disclosure with reference to accompanying drawings below.

Drawings illustrated herein are used for providing further understanding of the present disclosure and form part of the present disclosure, and illustrative embodiments of the present disclosure and description thereof are intended for explaining instead of improperly limiting the present disclosure. In the drawings:.

The electrode assembly and the manufacturing method thereof, the battery, the battery module and the battery pack described in the embodiments of the present disclosure are all applicable to various devices using batteries, for example, mobile phones, notebook computers, battery cars, electric vehicles, ships, space vehicles, electric toys, and electric tools, etc., for example, the space vehicles include airplanes, rockets, space shuttles, and spacecrafts, etc., the electric toys include fixed or mobile electric toys, for example, game machines, electric vehicle toys, electric ship toys, electric airplane toys, etc., the electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools and electric tools used in railways, for example, electric drills, electric grinders, electric wrenches, electric screw drivers, electric hammers, electric impact drills, concrete vibrators and electric planers.

The electrode assembly, the battery, the battery module and the battery pack described in the embodiments of the present disclosure are not only applicable to the devices described above, but also applicable to all the devices using batteries, however, to facilitate description, electric vehicles are taken as an example for illustration in the following embodiments.

For example, <FIG> is a structural schematic diagram of a vehicle <NUM> of an embodiment of the present disclosure. The vehicle <NUM> can be an oil-fueled vehicle, a gas vehicle or a new-energy vehicle, and the new-energy vehicle can be a battery electric vehicle, a hybrid electric vehicle or an extended range vehicle. A battery pack <NUM> can be arranged inside the vehicle <NUM>, for example, the battery pack <NUM> can be arranged at the bottom or the front or rear end of the vehicle <NUM>. The battery pack <NUM> can be used for the power supply of the vehicle <NUM>, for example, the battery pack <NUM> can serve as an operating power supply of the vehicle <NUM>, and serve as a circuit system of the vehicle <NUM>, for example, the battery pack <NUM> can satisfy power demands of the vehicle <NUM> during starting, navigation and operation of the vehicle <NUM>. In another embodiment of the present disclosure, the battery pack <NUM> can not only serve as an operational power supply of the vehicle <NUM>, but also serve as a driving power supply of the vehicle <NUM>, to substitute or partially substitute fuel oil or natural gas to provide driving power for the vehicle <NUM>.

To satisfy different requirements of electricity use, the battery pack <NUM> can include one battery module or a plurality of battery modules, wherein the plurality of battery modules can be connected in series or in parallel or in series and parallel, and the connection in series and parallel refers to a combination of series connection and parallel connection. For example, <FIG> is a structural schematic diagram of a battery pack <NUM> of another embodiment of the present disclosure. The battery pack <NUM> comprises a first case <NUM>, a second case <NUM> and a plurality of battery modules <NUM>, wherein the shapes of the first case <NUM> and the second case <NUM> are determined according to the combined shapes of the plurality of battery modules <NUM>, the first case <NUM> and the second case <NUM> are both provided with an opening, for example, the first case <NUM> and the second case <NUM> can both be hollow cuboids with only one surface being an opening surface respectively, that is, the surface has no case wall, such that the inside and the outside of the case are communicated, the first case <NUM> and the second case <NUM> are buckled with each other at the opening to form a closed case of the battery pack <NUM>, and after the plurality of battery modules <NUM> are connected in parallel or connected in series or connected in series and parallel, the plurality of battery modules <NUM> are placed in the case formed after the first case <NUM> is buckled with the second case <NUM>.

In another embodiment of the present disclosure, when the battery pack <NUM> comprises a battery module <NUM>, the battery module <NUM> is placed in the case formed after the first case <NUM> is buckled with the second case <NUM>.

The electricity generated through the one or more battery modules <NUM> penetrates through the case through a conducting mechanism and is led out.

According to different power demands, the battery module <NUM> can also include one or more batteries, as shown in <FIG>, the battery module <NUM> comprises a plurality of batteries <NUM>, and the plurality of batteries <NUM> can be connected through a manner of series connection, parallel connection or series and parallel connection, to realize a large capacity or power. For example, the battery <NUM> comprises, but is not limited to, a lithium ion secondary battery, a lithium ion primary battery, a lithium sulfur battery, a sodium lithium ion battery, or a magnesium ion battery. The battery <NUM> can be cylindrical, flat, and rectangular or of other shapes.

In another embodiment of the present disclosure, a plurality of batteries <NUM> can be superimposed together, and the plurality of batteries <NUM> can be connected in series, in parallel or in series and parallel. In another embodiment of the present disclosure, each battery <NUM> can be square, cylindrical or of other shapes. For example, <FIG> is a structural schematic diagram of a battery <NUM> of another embodiment of the present disclosure, the battery <NUM> comprises one or more electrode assemblies <NUM>, a case <NUM> and an end cover assembly <NUM>. The shape of the case <NUM> can be determined according to the combined shapes of one or more electrode assemblies <NUM>, for example, the case <NUM> can be a hollow cuboid or cube or cylinder, moreover, one of the surfaces of the case <NUM> is provided with an opening, such that one or more electrode assemblies <NUM> can be placed in the case <NUM>, for example, when the case <NUM> is a hollow cuboid or cube, one of the planes of the case <NUM> is an opening surface, that is, the plane has no case wall, such that the inside and the outside of the case <NUM> are communicated, when the housing <NUM> can be a hollow cylinder, the circular side face of the case <NUM> is an opening surface, that is, the circular side face has no case wall, such that the inside and the outside of the case <NUM> are communicated. The end cover assembly <NUM> is connected with the case <NUM> at the opening of the case <NUM> to form a closed case to place the battery <NUM>, and the case <NUM> is internally filled with electrolyte.

The end cover assembly <NUM> comprises an end cover <NUM> and a first terminal <NUM> and a second terminal <NUM> arranged on the end cover <NUM>, the end cover <NUM> is substantially flat, the first terminal <NUM> and the second terminal <NUM> are arranged on the flat surface of the end cover <NUM> and penetrate through the flat surface of the end cover <NUM>, the first terminal <NUM> and the second terminal <NUM> are correspondingly provided with a collector component <NUM>, and the collector component <NUM> is arranged between the end cover <NUM> and the electrode assembly <NUM>.

For example, as shown in <FIG>, each electrode assembly <NUM> is provided with a first tab <NUM> and a second tab <NUM>, the first tab <NUM> of one or more electrode assemblies <NUM> is connected with a first terminal <NUM> through a collector component <NUM>, and the second tab <NUM> of one or more electrode assemblies <NUM> is connected with the second terminal <NUM> through another collector component <NUM>. Moreover, the electrode assembly <NUM> further comprises a welding protection plate <NUM> arranged between the tab and the corresponding collector component <NUM>.

In another embodiment of the present disclosure, the flat surface of the end cover <NUM> can further be provided with an anti-explosion valve <NUM>, the anti-explosion valve <NUM> can be a part of the flat surface of the end cover <NUM>, and can also be welded with the flat surface of the end cover <NUM>. The anti-explosion valve <NUM> has a nick, and the depth of the nick is smaller than the thickness of other areas, except the nick, of the anti-explosion valve <NUM>, to achieve the purpose of not penetrating through the anti-explosion valve <NUM>, that is, under normal states, the anti-explosion valve <NUM> is in sealed combination with the end cover <NUM>, the end cover assembly <NUM> is connected with the case <NUM> at the opening of the case <NUM> through the end cover <NUM> to form a case for placing the battery <NUM>, and the space formed by the case is sealed and airtight. In the case, when the battery <NUM> produces too much gas, and when the gas expands such that the air pressure in the case rises to exceed a preset value, the anti-explosion valve <NUM> is cracked at the nick and the inside and the outside of the case are communicated, and gas is released outwards through the cracking point of the anti-explosion valve <NUM>, to further avoid explosion.

In the battery <NUM>, according to actual use demands, a single or a plurality of electrode assemblies <NUM> can be arranged, and as shown in <FIG>, the battery <NUM> is internally provided with at least two independent electrode assemblies <NUM>.

In some embodiments, as shown in <FIG>, the electrode assembly <NUM> comprises: a plurality of first electrode plates <NUM> and at least one second electrode plate <NUM>, wherein the polarity of the first electrode plate <NUM> is opposite to the polarity of the second electrode plate <NUM>, for example, the first electrode plate <NUM> is a positive electrode plate, and the second electrode plate <NUM> is a negative electrode plate, and vice versa. The plurality of first electrode plates <NUM> and the at least one second electrode plate <NUM> are wound around a winding axis K to form a winding structure, in the winding structure, the plurality of first electrode plates <NUM> and the at least one second electrode plate <NUM> are arranged in a superimposing manner along a direction vertical to the winding axis K.

The number of the first electrode plate <NUM> and the second electrode plate <NUM> can be the same and can also be different. In some embodiments, the sum of the number of all the first electrode plates <NUM> and all the second electrode plates <NUM> is greater than or equal to <NUM>. For example, the electrode assembly <NUM> comprises two, three or four first electrode plates <NUM> and one, two, three or four second electrode plates <NUM>.

In the embodiment of the present disclosure, the shape of each first electrode plate <NUM> is substantially the same as the shape of each second electrode plate <NUM>, for example, after the winding structure is flattened, the first electrode plates <NUM> and the second electrode plates <NUM> are substantially strip-shaped, for example, the first electrode plates <NUM> and the second electrode plates <NUM> can be strip-shaped with a length of <NUM>-<NUM>. The length difference between the first electrode plates <NUM> and the second electrode plates <NUM> is within a preset range, and the width sizes are substantially the same. After a plurality of first electrode plates <NUM> and at least one second electrode plate <NUM> are superimposed, a winding structure can be obtained when the plurality of first electrode plates <NUM> and at least one second electrode plate <NUM> are wound along a strip direction. The winding structure has a winding axis K, and the superimposing surface in which the plurality of first electrode plates <NUM> are superimposed with the at least one second electrode plate <NUM> is substantially in parallel with the winding axis K.

In another embodiment of the present disclosure, the plurality of first electrode plates <NUM> and at least one second electrode plate <NUM> can be superimposed in multiple forms, for example, when the plurality of first electrode plates <NUM> are two or more first electrode plates <NUM> and the at least one second electrode plate <NUM> is also two or more second electrode plates <NUM>, after the winding structure is flattened, one first electrode plate <NUM> and one second electrode plate <NUM> can be superimposed alternately in sequence. For another example, when the plurality of first electrode plates <NUM> are two or more first electrode plates <NUM> and the at least one second electrode plate <NUM> is one second electrode plate <NUM>, after the winding structure is flattened, two or more first electrode plates <NUM> and one second electrode plate <NUM> can be superimposed alternately in sequence.

When a plurality of first electrode plates <NUM> are superimposed with at least one second electrode plate <NUM>, a separator <NUM> is further arranged between any adjacent one first electrode plate <NUM> and one second electrode plate <NUM>, and the separator <NUM> is configured to separate the adjacent first electrode plate <NUM> from the second electrode plate <NUM>, such that the adjacent first electrode plate <NUM> and the second electrode plate <NUM> are not in short circuit with each other.

In another embodiment of the present disclosure, electrode plates of different polarities are adjacent to each other, for example, that is, the first electrode plates <NUM> being adjacent to the second electrode plates <NUM> means that no other electrode plate but at least one layer of separator <NUM> exists between the first electrode plates <NUM> and the second electrode plates <NUM>, for example, no other first electrode plate <NUM> or second electrode plate <NUM> exists between the first electrode plates <NUM> and the second electrode plates <NUM>, and can also be understood as that the first electrode plates <NUM> and the second electrode plates <NUM> are most directly adjacent to each other, for example, on the basis of one electrode plate with one polarity, the electrode plate with the polarity and the first layer of electrode plates with different polarities adjacent to the electrode plate with the polarity are called adjacent electrode plates.

In another embodiment of the present disclosure, two electrode plates of the same polarity being adjacent means that only one electrode plate of other polarity exists between two electrode plates of the same polarity, for example, two first electrode plates <NUM> being adjacent means that only one second electrode plate <NUM> exists between two first electrode plates <NUM>, and two second electrode plates <NUM> being adjacent means that only one first electrode plate <NUM> exists between two second electrode plates <NUM>. In another embodiment of the present disclosure, when no other electrode plate of a different polarity exists between two electrode plates of the same polarity, the two electrode plates of the same polarity can be taken as one electrode plate.

In another embodiment of the present disclosure, when no other electrode plates of a different polarity and separators exist between two or more electrode plates of the same polarity, the two electrode plates of the same polarity can be taken as one group of electrode plates, then during superimposing, the electrode plate group of the same polarity and another electrode plate group of a different polarity or a single electrode plate are superimposed alternately in sequence, for example, two or more first electrode plates constitute a first electrode plate group, and two or more second electrode plates constitute a second electrode plate group. The superimposing can be as follows: the first electrode plate group and the second electrode plate group are superimposed alternately in sequence, the first electrode plate group and a single second electrode plate are superimposed alternately in sequence, or, the second electrode plate group and the single first electrode plate are superimposed alternately in sequence.

Since the electrode plate group of the same polarity can be taken as one electrode plate, therefore, to facilitate description, one electrode plate described subsequently not only can be a single electrode plate, but also can be a electrode plate group composed of a plurality of electrode plates of the same polarity.

However, regardless of the superimposing manners, at least one layer of separator <NUM> is arranged between adjacent electrode plates of different polarities.

In another embodiment of the present disclosure, the separator <NUM> comprises a separator base layer and a functional layer, wherein the separator base layer can be at least one selected from polypropylene, polyethylene, ethylene-propylene copolymer, and polybutylene terephthalate, and the functional layer can be a mixture layer of ceramic oxides and binder. In another embodiment of the present disclosure, after the winding structure is flattened, the separator <NUM> is a thin film which exists separately, and is substantially strip-shaped, for example, a strip shape with a length of <NUM>-<NUM>. In another embodiment of the present disclosure, the separator <NUM> is coated on the surface of the first electrode plates <NUM> and/or the second electrode plates <NUM>, that is, the separator <NUM> and the first electrode plates <NUM> and/or the second electrode plates <NUM> are of an integrated structure.

In another embodiment of the present disclosure, as shown in <FIG>, in the winding structure, the first electrode plates <NUM> and the second electrode plates <NUM> are superimposed alternately in sequence, wherein A-A is the direction at which a plurality of first electrode plates <NUM> are superimposed with at least one second electrode plate <NUM>, and K is the winding axis K of the winding structure.

In another embodiment of the present disclosure, as shown in <FIG>, each first electrode plate <NUM> in a plurality of first electrode plates <NUM> comprises a first current collector <NUM> and a first active substance layer <NUM> arranged on a superimposing surface of the first current collector <NUM>, and the first current collector <NUM> comprises a first main body portion <NUM> provided with a first active substance layer <NUM> and at least one first tab <NUM> which protrudes from the first main body portion <NUM> along the direction of the winding axis K. Wherein the first tab <NUM> and the first main body portion <NUM> are arranged in parallel along the winding axis K. The second electrode plate <NUM> comprises a second current collector <NUM> and a second active substance layer <NUM> arranged on a superimposing surface of the second current collector <NUM>, and the second current collector <NUM> comprises a second main body portion <NUM> provided with a second active substance layer <NUM> and a second tab <NUM> which protrudes from the second main body portion <NUM> along the direction of the winding axis K.

In another embodiment of the present disclosure, when a plurality of first electrode plates <NUM> and at least one second electrode plate <NUM> are superimposed, that is, in the winding structure, the first tab <NUM> of the first electrode plate <NUM> and the second tab <NUM> of the second electrode plate <NUM> not only can be arranged at the same side, along the winding axis K, of the winding structure, but also can be arranged at different sides.

In another embodiment of the present disclosure, any two first tabs <NUM> in all the first tabs <NUM> are at least partially overlapped. For example, one electrode plate in the plurality of first electrode plates <NUM> is provided with a first tab <NUM>, the other electrode plate in the plurality of first electrode plates <NUM> is provided with a first tab <NUM>, the two first tabs <NUM> are at least partially overlapped. For another example, one of the electrode plates in the plurality of first electrode plates <NUM> is provided with a plurality of first tabs <NUM>, and any two first tabs <NUM> in the above plurality of first tabs <NUM> are at least partially overlapped. For still another example, one of the electrode plate in the plurality of first electrode plates <NUM> is provided with a plurality of first tabs <NUM>, the other electrode plate in the plurality of first electrode plates <NUM> is provided with a plurality of first tabs <NUM>, any arbitrary first tab <NUM> of one of the electrode plates and any arbitrary first tab <NUM> of the other electrode plate are at least partially overlapped.

It can be known from the above description that, to achieve the same energy, the electrode assembly of the present embodiment is equivalent to be obtained when a single first electrode plate with the length being equal to the sum of lengths of a plurality of first electrode plates <NUM> is segmented into a plurality of first electrode plates <NUM> and then the plurality of first electrode plates <NUM> are wound in parallel. A plurality of electrode plates with the same polarity are available inside the electrode assembly of the present embodiment, and the internal resistance of the electrode assembly is smaller, thereby reducing the calorific value of the electrode assembly in the using process, and improving the performance of the electrode assembly.

Moreover, compared with alignment of a plurality of tabs on the electrode plates with the same polarity when a single electrode plate, with the length being equal to the sum of lengths of a plurality of first electrode plates <NUM>, is wound, in the electrode assembly of the present embodiment, winding is performed after the tabs on a plurality of first electrode plates <NUM> with the same polarity are superimposed and aligned in parallel, the length of the electrode plate is shortened, and the number of winding turns is reduced, thereby improving the capability of controlling misplacement of tabs in the winding process, reducing the amount of misplacement between a plurality of first tabs <NUM> after winding, facilitating connection with the collector component, and further enhancing the over-current capacity of the tab, and improving the quality of the electrode assembly.

In addition, in the related technology, the area on a side, along a direction vertical to the winding axis K, of the first main body portion is not coated with an active substance layer, and the tab is welded to the area. While in the present embodiment, the first tab <NUM> and the first main body portion <NUM> are distributed in parallel along the winding axis K, and a first active substance layer is arranged in the direction, vertical to the winding axis K, of the first main body portion, thereby enlarging the area, coated with the first active substance layer <NUM>, on the first current collector <NUM>, and further improving the energy density of the electrode assembly.

In another embodiment of the present disclosure, after the winding structure is flattened, the structure of the first electrode plate <NUM> is as shown in <FIG>, each first electrode plate of the present embodiment comprises a plurality of first tabs <NUM>, and through setting a plurality of first tabs <NUM>, the over-current capacity can be improved.

In another embodiment of the present disclosure, the first tab <NUM> is formed by cutting the uncoated area of the first current collector <NUM>. In the winding structure after winding, each first electrode plate <NUM> is provided with at least one first tab <NUM> on each of its circles. For example, each first electrode plate <NUM> is provided with a first tab <NUM> or two first tabs <NUM> on each of its circles.

In another embodiment of the present disclosure, after the electrode assembly <NUM> is wound and formed, a plurality of first tabs <NUM> are laminated together and are welded to the collector component <NUM>.

To prevent unwelded areas of a plurality of first tabs <NUM> from being in a dispersed state after welding, meanwhile, since the first tab <NUM> is thin, in the assembly process of the battery, the first tab <NUM> is easily deformed and is squeezed between the first electrode plate <NUM> and the second electrode plate <NUM> to cause the risk of short circuit.

The first electrode plate <NUM> of the present embodiment is provided with an insulating layer <NUM> to play a role of insulation protection, for example, please refer to <FIG>, the insulating layer <NUM> is arranged on the surface of a root part of the first tab <NUM>, and the insulating layer <NUM> plays a role of insulation protection, even if when the first tab <NUM> is inserted between the first electrode plate <NUM> and the second electrode plate <NUM>, the insulating layer <NUM> can also effectively isolate the first tab <NUM> from the second electrode plate <NUM> to reduce the risk of short circuit and improve the safety performance.

Please refer to <FIG>, the insulating layer <NUM> comprises a first part 15a and a second part 15b, the first part 15a is arranged (for example, coated) on the superimposing surface of the first main body portion <NUM> and is connected to an end, adjacent to the first tab <NUM>, of the first active substance layer <NUM>, and the second part 15b extends from the end, far away from the first active substance layer <NUM>, of the first part 15a and is arranged (for example, coated) on the superimposing surface of the first tab <NUM>. The second part 15b can cover the root area, adjacent to the first main body portion <NUM>, of the first tab <NUM>, and effectively reduces the risk of contact between the root area of the first tab <NUM> and the first active substance layer <NUM>.

For example, the first active substance layer <NUM> and the first part 15a are distributed, along two end sides of the winding axis K, of the superimposing surface of the first main body portion <NUM>, and the first tab <NUM> and the first part 15a are arranged on the same end side of the first main body portion <NUM>, for example, the first tab <NUM> extends from the first part 15a towards the outer side of the first main body portion <NUM> along the direction of the winding axis K.

For example, the first active substance layer <NUM> and the first part 15a being distributed on the superimposing surface of the first main body portion <NUM> along two end sides of the winding axis K can also be understood as follows: the first active substance layer <NUM> and the first part 15a are substantially parallel areas on the superimposing surface of the first main body portion <NUM> and are distributed in two layers on the superimposing surface of the first main body portion <NUM> along the winding axis K, that is, the first active substance layer <NUM> and the first part 15a are substantially parallel on the superimposing surface of the first main body portion <NUM> along the strip direction of the first electrode plate <NUM> and are distributed in two layers.

The insulating layer <NUM> comprises inorganic fillers and binder. The inorganic fillers include one or more of boehmite, aluminium oxide, magnesium oxide, titanium dioxide, zirconium oxide, silicon dioxide, silicon carbide, boron carbide, calcium carbonate, aluminium silicate, calcium silicate, potassium titanate, and barium sulfate. The binder comprises one or more of polyvinylidene fluoride, polyacrylonitrile, polyacrylic acid, polyacrylic ester, polyacrylate-acrylate, polyacrylonitrile-acrylic acid, and polyacrylonitrile-acrylic ester.

Any two first tabs in all the first tabs of the present embodiment are at least partially overlapped. The number of winding turns of the electrode assembly <NUM> of the present embodiment is reduced, and the amount of misplacement between a plurality of first tabs <NUM> after winding can be reduced, thereby improving the over-current capacity of the tab.

Before winding, the structure of the second electrode plate <NUM> is as shown in <FIG>. The second electrode plate <NUM> of the present embodiment further comprises a third active substance layer <NUM>, the third active substance layer <NUM> is arranged (for example, coated) on the area, connected with the second active substance layer <NUM>, on the surface of the second tab <NUM>, for example, the third active substance layer <NUM> is arranged (for example, coated) on the surface of the root part of the second tab <NUM>. The third active substance layer <NUM> and the second active substance layer <NUM> are molded.

In the assembly process of the battery, the areas, uncoated with the third active substance layer <NUM>, of a plurality of second tabs <NUM> are gathered and welded to the collector component <NUM>. The third active substance layer <NUM> has a large elastic modulus, can effectively support the second tab <NUM>, and reduce the risk of insertion of the second tab <NUM> between the first electrode plate <NUM> and the second electrode plate <NUM>.

Specifically, the first current collector <NUM> of the present embodiment is an aluminium foil, the first active substance layer <NUM> comprises ternary materials, lithium manganate or lithium iron phosphate; and the second current collector <NUM> is a copper foil, and the second active substance layer <NUM> comprises graphite or silicon.

In the present embodiment, a plurality of first electrode plates <NUM> and a plurality of second electrode plates <NUM> are available, for example, the number of the first electrode plates <NUM> and the second electrode plates <NUM> can be selected to be <NUM>-<NUM>, to ensure easy winding on the basis of reducing the length of the electrode plate, and prevent a dramatic increase in the required winding force when the number of the electrode plates is large, or prevent falling off of the active substance coated on the surface of the electrode plate.

The winding structure of the electrode assembly of the present embodiment is flat and comprises a straight section and turning sections arranged on two sides of the straight section. The superimposing surfaces of the electrode plates in the straight section are substantially parallel and are substantially parallel with the winding axis K, the straight section comprises, in the plane vertical to the winding axis K, a first straight sub-section and a second straight sub-section which are substantially parallel and which are distributed in symmetry about the winding axis K, and the two turning sections are respectively arranged in the first straight sub-section and the second straight sub-section to combine into two sides of the straight section.

All the first tabs <NUM> in the present embodiment are arranged in the straight section. In this way, when a plurality of first tabs <NUM> are arranged in a laminated manner and are connected, the contact area between the first tabs <NUM> is enlarged, and the over-current capacity is enhanced. Moreover, further, all the first tabs <NUM> of the present embodiment are arranged in the first straight sub-section, thereby reducing the thickness after the first tabs <NUM> are superimposed when ensuring the over-current capacity of the first tab <NUM>, and further reducing the space occupied by the first tab <NUM>.

In the embodiments not shown in other drawings, all the first tabs can also be arranged in the second straight sub-section. Or a part of all the first tabs are arranged in the first straight sub-section, and the other part of the first tabs are arranged in the second straight sub-section.

According to the invention, the electrode assembly <NUM> comprises a plurality of first electrode plates <NUM>, and the positions of the winding initial ends of at least two first electrode plates <NUM> in the plurality of first electrode plates <NUM> are different. Moreover, the positions of the winding tail ends of at least two first electrode plates <NUM> in the plurality of first electrode plates <NUM> are optionally also different. For example, the positions of the winding initial ends of all the first electrode plates <NUM> are different, and the positions of the winding tail ends are different.

In another embodiment of the present disclosure, the electrode assembly <NUM> comprises a plurality of second electrode plates <NUM>, and the positions of the winding initial ends of at least two second electrode plates <NUM> in the plurality of second electrode plates <NUM> are different. Moreover, the positions of the winding tail ends of at least two second electrode plates <NUM> in the plurality of second electrode plates <NUM> are different. For example, the positions of the winding initial ends of all the second electrode plates <NUM> are different, and the positions of the winding tail ends are different.

The electrode assembly <NUM> will expand during the using process, and will exert an acting force onto the case <NUM> after the electrode assembly <NUM> expands, meanwhile, the case <NUM> exerts a counter-acting force onto the electrode assembly <NUM>. As to the electrode assembly <NUM> of the present disclosure, the number of layers of the first electrode plates <NUM> and the second electrode plates <NUM> is increased, such a structure can prevent the formation of a thick step at the winding tail end E of a plurality of first electrode plates <NUM> or a plurality of second electrode plates <NUM>, when the outer layer of the winding structure is subjected to a counter-acting force of the case <NUM>, the problem of concentration of stress at the winding tail end E of the electrode plate can be alleviated, such that the winding structure is subjected to a uniform stress at different circumferential positions, thereby preventing great deformation of the winding structure or preventing falling off of active substance at partial areas with a large stress, and improving the operating performance and reliability of the battery after long-term use.

In another embodiment of the present disclosure, the electrode assembly comprises a plurality of first electrode plates <NUM> and a plurality of second electrode plates <NUM>, the positions of the winding initial ends S of at least two first electrode plates <NUM> in the plurality of first electrode plates <NUM> are different, for example, the positions of the winding initial ends S of all the first electrode plates <NUM> are different; and/or, the positions of the winding initial ends S' of at least two second electrode plates <NUM> in the plurality of second electrode plates <NUM> are different, for example, the positions of the winding initial ends S' of all the second electrode plates <NUM> are different.

The electrode assembly <NUM> will expand during the using process, as to the electrode assembly <NUM> of the present disclosure, the positions of the respective first winding initial end S of at least two first electrode plates <NUM> are set to be different, and/or the positions of the respective second winding initial end S' of at least two second electrode plates <NUM> are set to be different, that is, the first winding initial ends S of at least two first electrode plates <NUM> are arranged in a staggered manner in the circumferential direction of the winding structure, and/or the second winding initial ends S' of at least two second electrode plates <NUM> are arranged in a staggered manner in the circumferential direction of the winding structure, such that the positions of the winding initial ends of the first electrode plates <NUM> and/or the second electrode plates <NUM> are different, and the formation of a thick step at the winding initial ends of the plurality of first electrode plates <NUM> or the plurality of second electrode plates <NUM> can be prevented, the problem of concentration of stress at the winding initial ends of the electrode plates can be alleviated, such that the winding structure is subjected to a uniform stress at different circumferential positions, thereby preventing great deformation of the winding structure or preventing falling off of active substance at partial areas with a large stress, and improving the operating performance and reliability of the battery after long-term use.

In another embodiment of the present disclosure, the winding tail ends of at least one first electrode plate <NUM> in a plurality of first electrode plates <NUM> are arranged in the turning section. The winding tail ends of at least one second electrode plate <NUM> in the plurality of second electrode plates <NUM> are arranged in the turning section.

When the winding tail ends of the first electrode plate <NUM> and the second electrode plate <NUM> are both arranged in the turning section, the difference between the number of layers of the electrode plates of the first straight sub-section and the second straight sub-section can be reduced, when the electrode assembly <NUM> expands and is in contact with the case <NUM>, and when an inner wall of the case <NUM> exerts a counter-acting force onto two planes of the electrode assembly <NUM>, the stress applied to the electrode plates of the first straight sub-section and the second straight sub-section is consistent.

In another embodiment of the present disclosure, in different radial directions of the winding structure, the difference of the number of layers of electrode plates does not exceed the number of preset layers. For example, the number of preset layers is smaller than or equal to the sum of the number of the plurality of first electrode plates <NUM> and the plurality of second electrode plates <NUM>, for example, after two first electrode plates <NUM> and two second electrode plates <NUM> are wound, in one of the radial directions of the winding structure, the number of layers of electrode plates is <NUM>, in another radial direction of the winding structure, the number of the layers of electrode plates is <NUM> to the minimum, and <NUM> to the maximum, that is, the number of preset layers is smaller than or equal to the sum of the number of two first electrode plates <NUM> and two second electrode plates <NUM>, wherein the sum is <NUM>.

When the electrode assembly <NUM> expands and is in contact with the case <NUM>, the case <NUM> will exert a counter-acting force onto the electrode assembly <NUM>, when the difference of number of layers of electrode plates does not exceed the number of preset layers in different radial directions of the winding structure, the stress on the electrode assembly <NUM> at each point of the circumferential direction is more uniform, thereby preventing larger difference of performances at various points of the electrode assembly <NUM> in the using process. For example, two first electrode plates <NUM> are arranged, two second electrode plates <NUM> are arranged, the number of preset layers is smaller than or equal to four, the smaller the difference of the number of layers of the electrode plates is, the more uniform the stress on the electrode assembly <NUM> at each point of the circumferential direction of the winding structure is.

The electrode assembly <NUM> can include at least two first electrode plates <NUM> and at least two second electrode plates <NUM>, however, to facilitate description, two first electrode plates <NUM> and two second electrode plates <NUM> are taken as an example for illustration in the following embodiments.

The external shape of the winding structure of the electrode assembly <NUM> can be a cylindrical shape, a flat shape, an ellipsoid shape, a cube shape, a cuboid shape or other arbitrary shapes. However, to facilitate description, the winding structure of the electrode assembly <NUM> being a flat shape and a cylinder shape is respectively taken as an example for illustration below.

<FIG> is a structural schematic diagram showing that a flat electrode assembly in another embodiment of the present disclosure is vertical to the cross section of the winding axis K. The electrode assembly <NUM> comprises a first negative electrode plate <NUM>, a second negative electrode plate <NUM>, a first positive electrode plate <NUM>, a second negative electrode plate <NUM> and a plurality of separators <NUM>, wherein the first negative electrode plate <NUM>, the first positive electrode plate <NUM>, the second negative electrode plate <NUM> and the second positive electrode plate <NUM> are superimposed alternately in sequence, and the first negative electrode plate <NUM> is separated from the first positive electrode plate <NUM> through a separator <NUM>, the first positive electrode plate <NUM> is separated from the second negative electrode plate <NUM> through another separator <NUM>, the second negative electrode plate <NUM> is separated from the second positive electrode plate <NUM> through another separator <NUM>, and all the first negative electrode plates <NUM>, the second negative electrode plates <NUM>, the first positive electrode plates <NUM>, the second positive electrode plates <NUM> and the plurality of separators <NUM> are superimposed and then wound around the winding axis K to form a flat winding structure.

In the electrode assembly <NUM> in the present embodiment, as to the structures and positions of the tabs of the positive electrode plates and the tabs of the negative electrode plate, please refer to the related contents of the first tabs of the first electrode plates and the second tabs of the second electrode plates described in the above embodiments of <FIG>, which will not be repeated redundantly herein.

In the present embodiment, as to the following specific conditions: on different radial directions of the winding structure of the electrode assembly <NUM>, that is, at different positions of the circumferential direction of the winding structure, the difference between the number of layers of electrode plates is no greater than the number of preset layers, please also refer to the related contents described in the above embodiments of <FIG>, which will not be repeated redundantly herein.

In the winding structure, the innermost ring in the winding structure is a ring enclosed by the first negative electrode plates <NUM>, and the outermost ring of the winding structure is a ring enclosed by the second negative electrode plates <NUM>.

In the present embodiment, the winding structure of the electrode assembly <NUM> comprises a straight section 10A and turning sections 10B arranged on two sides of the straight section 10A, wherein the superimposing surface of the electrode plate in the straight section 10A is a substantially parallel plane and is substantially in parallel with the winding axis, the plane herein is not exactly a plane, and a certain error is allowed. In a plane vertical to the winding axis K, the straight section 10A comprises a first straight sub-section 10A1 and a second straight sub-section 10A2 which are substantially parallel and distributed symmetrically about the winding axis K, and the two turning sections 10B are respectively arranged in the first straight sub-section 10A1 and the second straight sub-section 10A2 to combine into two sides of the straight section 10A.

In the winding structure of the electrode assembly, all the negative tabs of the first negative electrode plate <NUM> and all the negative tabs of the second negative electrode plate <NUM> can all be arranged in the straight section 10A, for example, all the negative tabs are arranged in the first straight sub-section 10A1 or all the negative tabs are arranged in the second straight sub-section 10A2, or, part of the negative tabs are arranged in the first straight sub-section 10A1, and the other part of the negative tabs are arranged in the second straight sub-section 10A2, however, the negative tabs arranged in the same area are at least partially overlapped in the direction vertical to the winding axis, for example, they are substantially overlapped.

All the positive tabs of the first positive electrode plate <NUM> and all the positive tabs of the second positive electrode plate <NUM> can all be arranged in the straight section 10A, for example, all the positive tabs are arranged in the first straight sub-section 10A1 or all the positive tabs are arranged in the second straight sub-section 10A2, or, part of the positive tabs are arranged in the first straight sub-section 10A1, and the other part of the positive tabs are arranged in the second straight sub-section 10A2, however, the positive tabs arranged in the same area are at least partially overlapped in the direction vertical to the winding axis, for example, they are substantially overlapped.

The positions of the first winding initial ends S of the first positive electrode plates <NUM> and the second positive electrode plates <NUM> are the same, for example, the first winding initial ends S of the first positive electrode plates <NUM> and the second positive electrode plates <NUM> are both arranged in the straight sub-section (for example, the first straight sub-section 10A1) on the same side of the straight section 10A, and the first winding initial ends S of the first positive electrode plates <NUM> and the second positive electrode plates <NUM> are flush.

The positions of the second winding initial ends S' of the first negative electrode plate <NUM> and the second negative electrode plate <NUM> are also the same, for example, the second winding initial ends S' of the first negative electrode plate <NUM> and the second negative electrode plate <NUM> are both arranged in the straight sub-section (for example, the first straight sub-section 10A1) on the same side of the straight section 10A, and the second winding initial ends S' of the first negative electrode plate <NUM> and the second negative electrode plate <NUM> are flush.

Along a reverse direction of the winding direction, the second winding initial end S' of the first negative electrode plate <NUM> exceeds the first winding initial end S of the first positive electrode plate <NUM>. The second winding initial end S' of the second negative electrode plate <NUM> exceeds the first winding initial end S of the second positive electrode plate <NUM>.

The positions of the first winding tail ends E of the first positive electrode plates <NUM> and the second positive electrode plates <NUM> are the same, for example, the first winding tail ends E of the first positive electrode plates <NUM> and the second positive electrode plates <NUM> are both arranged at the turning section (for example, the first turning section 10B1) on the same side, and the first winding tail ends E of the first positive electrode plates <NUM> and the second positive electrode plates <NUM> are flush.

The positions of the second winding tail ends E' of the first negative electrode plate <NUM> and the second negative electrode plate <NUM> are also the same, for example, the second winding tail ends E' of the first negative electrode plate <NUM> and the second negative electrode plate <NUM> are both arranged in the turning section (for example, the first turning section 10B1) on the same side, and are also arranged at the turning section (for example, the first turning section 10B1) of the same side as the first winding tail ends E of the first positive electrode plates <NUM> and the second positive electrode plates <NUM>, and the second winding tail ends E' of the first negative electrode plate <NUM> and the second negative electrode plate <NUM> are flush.

Along a winding direction, the second winding tail end E' of the first negative electrode plate <NUM> exceeds the first winding tail end E of the second positive electrode plate <NUM>, and the second winding tail end E' of the second negative electrode plate <NUM> exceeds the first winding tail end E of the first positive electrode plate <NUM>.

The winding structure of the electrode assembly described above can enable the length differences of a plurality of electrode plates before winding to be approximate, thereby being easy to wind.

<FIG> is a structural schematic diagram showing that a flat electrode assembly is vertical to the cross section of the winding axis K in another embodiment of the present disclosure. The electrode assembly <NUM> comprises a first negative electrode plate <NUM>, a second negative electrode plate <NUM>, a first positive electrode plate <NUM>, a second positive electrode plate <NUM> and a plurality of separators <NUM>, wherein the first negative electrode plate <NUM>, the first positive electrode plate <NUM>, the second negative electrode plate <NUM> and the second positive electrode plate <NUM> are superimposed alternately in sequence, and the first negative electrode plate <NUM> is separated from the first positive electrode plate <NUM> through a separator <NUM>, the first positive electrode plate <NUM> is separated from the second negative electrode plate <NUM> through another separator <NUM>, the second negative electrode plate <NUM> is separated from the second positive electrode plate <NUM> through another separator <NUM>, and all the first negative electrode plates <NUM>, the second negative electrode plates <NUM>, the first positive electrode plates <NUM>, the second positive electrode plates <NUM> and a plurality of separators <NUM> are superimposed and then wound around a winding axis K to form a flat winding structure.

All the positive tabs of the first positive electrode plate <NUM> and all the positive tabs of the second positive electrode plate <NUM> can all be arranged in the straight section 10A, for example, all the positive tabs are arranged in the first straight sub-section 10A1 or all the positive tabs are arranged in the second straight sub-section 10A2, or, part of the positive tabs are arranged in the first straight sub-section 10A1, and the other part of the positive tabs are arranged in the second straight sub-section 10A2, however, the positive tabs arranged in the same area are at least partially overlapped in the direction vertical to the winding axis, for example, they are substantially overlapped. The structure of the electrode assembly <NUM> of the present embodiment is substantially similar to the structure of the electrode assembly described in the embodiment of <FIG>, and the difference will be described below.

In the winding structure of the electrode assembly <NUM> of the present embodiment, the innermost ring in the winding structure is a ring enclosed by the first negative electrode plates <NUM>, and the outermost ring of the winding structure is a ring enclosed jointly by the first negative electrode plates <NUM> and the second negative electrode plates <NUM>.

The first winding tail ends E of the first positive electrode plates <NUM> and the second positive electrode plates <NUM> are different, for example, the first winding tail ends E of the first positive electrode plates <NUM> and the second positive electrode plates <NUM> are respectively arranged at the second turning section 10B2 and the first turning section 10B1.

The positions of the second winding tail ends E' of the first negative electrode plate <NUM> and the second negative electrode plate <NUM> are also different, for example, the second winding tail ends E' of the first negative electrode plate <NUM> and the second negative electrode plate <NUM> are respectively arranged at the first turning section 10B1 and the second turning section 10B2.

The winding structure of the electrode assembly described above can reduce the step formed by the first positive electrode plate <NUM> and the second positive electrode plate <NUM> at the first winding tail end E, and reduce the step formed by the first negative electrode plate <NUM> and the second negative electrode plate <NUM> at the second winding tail end E', so as to reduce local stress exerted onto the electrode plate at the winding tail end after the electrode assembly is in contact with the housing when the electrode assembly expands, prevent cracking of the electrode plate or falling off of the active substance, and improve the reliability of long-term operation of the electrode assembly.

<FIG> is a structural schematic diagram showing that a flat electrode assembly is vertical to the cross section of the winding axis K in another embodiment of the present disclosure. The electrode assembly <NUM> comprises a first negative electrode plate <NUM>, a second negative electrode plate <NUM>, a first positive electrode plate <NUM>, a second positive electrode plate <NUM> and a plurality of separators <NUM>, wherein the first negative electrode plate <NUM>, the first positive electrode plate <NUM>, the second negative electrode plate <NUM> and the second positive electrode plate <NUM> are superimposed alternately in sequence, and the first negative electrode plate <NUM> is separated from the first positive electrode plate <NUM> through a separator <NUM>, the first positive electrode plate <NUM> is separated from the second negative electrode plate <NUM> through another separator <NUM>, the second negative electrode plate <NUM> is separated from the second positive electrode plate <NUM> through another separator <NUM>, and all the first negative electrode plates <NUM>, the second negative electrode plates <NUM>, the first positive electrode plates <NUM>, the second positive electrode plates <NUM> and the plurality of separators <NUM> are superimposed and then wound around a winding axis K to form a flat winding structure.

The structure of the electrode assembly <NUM> of the present embodiment is substantially similar to the structure of the electrode assembly <NUM> described in the embodiment of <FIG>, and the difference will be described below.

In the winding structure of the electrode assembly <NUM> of the present embodiment, the innermost ring in the winding structure is a ring enclosed by the first negative electrode plates <NUM>, and the outermost ring of the winding structure is a ring enclosed by the second negative electrode plates <NUM>.

In the winding structure of the electrode assembly of the present embodiment, the positions of the second winding tail ends E' of the first negative electrode plate <NUM> and the second negative electrode plate <NUM> are different, for example, the second winding tail ends E' of the first negative electrode plate <NUM> and the second negative electrode plate <NUM> are all arranged at the same turning section (for example, the first turning section 10B1), and the second winding tail ends E' of the first negative electrode plate <NUM> and the second negative electrode plate <NUM> are not flush.

The winding structure of the electrode assembly <NUM> described above can reduce the difference between the number of layers of electrode plates of the first straight sub-section 14A1 and the second straight sub-section 14A2. When the electrode assembly expands and is in contact with the housing, and when the inner wall of the housing exerts a counter-acting force onto the two planes of the electrode assembly, the stress exerted onto the electrode plates of the first straight sub-section 14A1 and the second straight sub-section 14A2 is consistent.

The structure of the electrode assembly <NUM> of the present embodiment is substantially similar to the structure of the electrode assembly <NUM> described in the embodiment of <FIG>, and the difference will be described below. In the winding structure of the electrode assembly of the present embodiment, the innermost ring in the winding structure is a ring enclosed jointly by the first negative electrode plates <NUM> and the second negative electrode plates <NUM>, and the outermost ring of the winding structure is a ring enclosed by the second negative electrode plates <NUM>.

In the winding structure of the electrode assembly <NUM> of the present embodiment, the positions of the first winding initial ends S of the first positive electrode plates <NUM> and the second positive electrode plates <NUM> are different, for example, the first winding initial ends S of the first positive electrode plates <NUM> and the second positive electrode plates <NUM> are respectively arranged at the first straight sub-section 10A1 and the second straight sub-section 10A2, and the first winding initial ends S of the first positive electrode plates <NUM> and the second positive electrode plates <NUM> are not flush.

The positions of the second winding initial ends S of the first negative electrode plate <NUM> and the second negative electrode plate <NUM> are also different, for example, the second winding initial ends S of the first negative electrode plate <NUM> and the second negative electrode plate <NUM> are respectively arranged at the first straight sub-section 10A1 and the second straight sub-section 10A2, and the second winding initial ends S of the first negative electrode plate <NUM> and the second negative electrode plate <NUM> are not flush.

The winding structure of the electrode assembly described above can reduce the step formed by the first positive electrode plates <NUM> and the second positive electrode plates <NUM> at the first winding initial end S, and reduce the step formed by the first negative electrode plate <NUM> and the second negative electrode plate <NUM> at the second winding initial end S', so as to reduce local stress exerted onto the electrode plate at the winding initial end after the electrode assembly expands and is in contact with the housing <NUM>, prevent cracking of the electrode plate or falling off of the active substance, and improve the reliability of long-term operation of the electrode assembly.

The structure of the electrode assembly <NUM> of the present embodiment is substantially similar to the structure of the electrode assembly <NUM> described in the embodiment of <FIG>, and the difference will be described below. In the winding structure of the electrode assembly <NUM> of the present embodiment, the innermost ring in the winding structure is a ring enclosed jointly by the first negative electrode plates <NUM> and the second negative electrode plates <NUM>, and the outermost ring of the winding structure is a ring enclosed jointly by the first negative electrode plates <NUM> and the second negative electrode plates <NUM>.

The positions of the second winding initial ends S' of the first negative electrode plate <NUM> and the second negative electrode plate <NUM> are also different, for example, the second winding initial ends S' of the first negative electrode plate <NUM> and the second negative electrode plate <NUM> are respectively arranged at the first straight sub-section 10A1 and the second straight sub-section 10A2, and the second winding initial ends S' of the first negative electrode plate <NUM> and the second negative electrode plate <NUM> are not flush.

The positions of the first winding tail ends E of the first positive electrode plates <NUM> and the second positive electrode plates <NUM> are different, for example, the first winding tail ends E of the first positive electrode plates <NUM> and the second positive electrode plates <NUM> are respectively arranged at different turning sections 10B, and the first winding tail ends E of the first positive electrode plates <NUM> and the second positive electrode plates <NUM> are not flush.

The positions of the second winding tail ends E' of the first negative electrode plate <NUM> and the second negative electrode plate <NUM> are also different, for example, the second winding tail ends E' of the first negative electrode plate <NUM> and the second negative electrode plate <NUM> are respectively arranged at two different turning sections 10B, and the second winding tail ends E' of the first negative electrode plate <NUM> and the second negative electrode plate <NUM> are not flush.

The winding structure of the electrode assembly described above can simultaneously reduce the steps formed by the first positive electrode plates <NUM> and the second positive electrode plates <NUM> at the first winding initial end S and the first winding tail end E, and reduce the steps formed by the first negative electrode plates <NUM> and the second negative electrode plates <NUM> at the second winding initial end S' and the second winding tail end E', so as to reduce local stress exerted onto the electrode plate at the winding initial end and the winding tail end after the electrode assembly expands and is in contact with the housing <NUM>, prevent cracking of the electrode plate or falling off of the active substance, and improve the reliability of long-term operation of the electrode assembly.

On the basis of the above embodiments, on different radial directions of the winding structure, that is, at different circumferential positions of the winding structure, the difference of number of layers of electrode plates does not exceed a preset number of layers, the number of layers of electrode plates herein refers to the total number of layers of the positive electrode plates and negative electrode plates. Wherein the preset number of layers is smaller than or equal to the sum of the quantity of a plurality of positive electrode plates and the quantity of a plurality of negative electrode plates.

When the electrode assembly expands and is in contact with the housing <NUM>, the housing <NUM> will exert a counter-acting force onto the electrode assembly, such that the stress on each point of the circumferential direction of the electrode assembly is more uniform, thereby preventing the electrode assembly from having great difference in performances at various points in the using process. For example, two positive electrode plates are arranged, two negative electrode plates are arranged, the preset number of layers is smaller than or equal to four, and the smaller the difference of the number of layers of electrode plates is, the more uniform the stress exerted onto the electrode assembly at each point of the circumferential direction is.

<FIG> are structural schematic diagrams of a cylindrical electrode assembly.

<FIG> is a structural schematic diagram showing that a cylindrical electrode assembly is vertical to the cross section of the winding axis K in another embodiment of the present disclosure. The electrode assembly <NUM> comprises a first negative electrode plate <NUM>, a second negative electrode plate <NUM>, a first positive electrode plate <NUM>, a second positive electrode plate <NUM> and a plurality of separators <NUM>, wherein the first negative electrode plate <NUM>, the first positive electrode plate <NUM>, the second negative electrode plate <NUM> and the second positive electrode plate <NUM> are superimposed alternately in sequence, and the first negative electrode plate <NUM> is separated from the first positive electrode plate <NUM> through a separator <NUM>, the first positive electrode plate <NUM> is separated from the second negative electrode plate <NUM> through another separator <NUM>, the second negative electrode plate <NUM> is separated from the second positive electrode plate <NUM> through another separator <NUM>, and all the first negative electrode plates <NUM>, the second negative electrode plates <NUM>, the first positive electrode plates <NUM>, the second positive electrode plates <NUM> and the plurality of separators <NUM> are superimposed and then wound around a winding axis K to form a cylindrical winding structure.

In the electrode assembly in the present embodiment, as to the structures and positions of the tabs of the positive electrode plates and the tabs of the negative electrode plates, please refer to the related contents of the first tabs of the first electrode plate and the second tabs of the second electrode plate described in the above embodiments of <FIG>, which will not be repeated redundantly herein.

The positions of the first winding initial ends S of the first positive electrode plates <NUM> and the second positive electrode plates <NUM> are the same, for example, the first winding initial ends S of the first positive electrode plates <NUM> and the second positive electrode plates <NUM> are both arranged at the same radial direction of the winding structure, and the first winding initial ends S of the first positive electrode plates <NUM> and the second positive electrode plates <NUM> are flush.

The positions of the second winding initial ends S' of the first negative electrode plate <NUM> and the second negative electrode plate <NUM> are also the same, for example, the second winding initial ends S' of the first negative electrode plate <NUM> and the second negative electrode plate <NUM> are both arranged at the same radial direction of the winding structure, and the second winding initial ends S' of the first negative electrode plate <NUM> and the second negative electrode plate <NUM> are flush.

The positions of the first winding tail ends E of the first positive electrode plates <NUM> and the second positive electrode plates <NUM> are the same, for example, the first winding tail ends E of the first positive electrode plates <NUM> and the second positive electrode plates <NUM> are both arranged at the turning section 10B on the same side, and the first winding tail ends E of the first positive electrode plates <NUM> and the second positive electrode plates <NUM> are flush.

The positions of the second winding tail ends E' of the first negative electrode plate <NUM> and the second negative electrode plate <NUM> are also the same, for example, the second winding tail ends E' of the first negative electrode plate <NUM> and the second negative electrode plate <NUM> are both arranged in the same turning section 10B, and the second winding tail ends E' of the first negative electrode plate <NUM> and the second negative electrode plate <NUM> are flush.

The winding structure described above can enable the length differences of a plurality of electrode plates before winding to be approximate, thereby being easy to wind.

The structure of the electrode assembly <NUM> of the present embodiment is substantially similar to the structure of the electrode assembly <NUM> described in the embodiment of <FIG>, and the differences will be described below. In the winding structure of the present embodiment, the innermost ring of the winding structure is a ring enclosed jointly by the first negative electrode plates <NUM> and the second negative electrode plates <NUM>, and the outermost ring of the winding structure is a ring enclosed by the first negative electrode plates <NUM>.

In the winding structure of the present embodiment, the positions of the first winding initial ends S of the first positive electrode plates <NUM> and the second positive electrode plates <NUM> are different, for example, the first winding initial ends S of the first positive electrode plates <NUM> and the second positive electrode plates <NUM> are arranged at a relative radial direction of the winding structure, and the first winding initial ends S of the first positive electrode plates <NUM> and the second positive electrode plates <NUM> are not flush.

The positions of the second winding initial ends S of the first negative electrode plate <NUM> and the second negative electrode plate <NUM> are also different, for example, the second winding initial end S' of the first negative electrode plate <NUM> and the second winding initial end S' of the second negative electrode plate <NUM> are arranged at a relative radial direction of the winding structure, and the second winding initial ends S' of the first negative electrode plate <NUM> and the second negative electrode plate <NUM> are not flush.

The winding structure described above can reduce the step formed by the first positive electrode plates <NUM> and the second positive electrode plates <NUM> at the first winding initial end S, and reduce the step formed by the first negative electrode plate <NUM> and the second negative electrode plate <NUM> at the second winding initial end S', so as to reduce local stress exerted onto the electrode plate at the winding initial end after the electrode assembly expands and is in contact with the housing <NUM>, prevent cracking of the electrode plate or falling off of the active substance, and improve the reliability of long-term operation of the electrode assembly.

<FIG> is a structural schematic diagram showing that a cylindrical electrode assembly is vertical to the cross section of the winding axis K in another embodiment of the present disclosure. The electrode assembly <NUM> comprises a first negative electrode plate <NUM>, a second negative electrode plate <NUM>, a first positive electrode plate <NUM>, a second positive electrode plate <NUM> and a plurality of separators <NUM>, wherein the first negative electrode plate <NUM>, the first positive electrode plate <NUM>, the second negative electrode plate <NUM> and the second positive electrode plate <NUM> are superimposed alternately in sequence, and the first negative electrode plate <NUM> is separated from the first positive electrode plate <NUM> through a separator <NUM>, the first positive electrode plate <NUM> is separated from the second negative electrode plate <NUM> through another separator <NUM>, the second negative electrode plate <NUM> is separated from the second positive electrode plate <NUM> through another separator <NUM>, and all the first negative electrode plates <NUM>, the second negative electrode plates <NUM>, the first positive electrode plates <NUM>, the second positive electrode plates <NUM> and a plurality of separators <NUM> are superimposed and then wound around a winding axis K to form a flat winding structure.

The structure of the present embodiment is substantially similar to the structure described in the embodiment of <FIG>, and the differences will be described below. In the winding structure of the present embodiment, the innermost ring of the winding structure is a ring enclosed jointly by the first negative electrode plates <NUM> and the second negative electrode plates <NUM>, and the outermost ring of the winding structure is a ring enclosed by the first negative electrode plates <NUM>.

In the winding structure of the present embodiment, the positions of the first winding initial ends E of the first positive electrode plates <NUM> and the second positive electrode plates <NUM> are different, and the second winding tail ends E' of the first negative electrode plate <NUM> and the second negative electrode plate <NUM> are also different.

Along a winding direction, the first negative electrode plate <NUM> is arranged at the outermost layer and the end position of the second winding tail end E' exceeds the end position of the second winding tail end E' of the second negative electrode plate <NUM>, and the end position of the second winding tail end E' of the first positive electrode plates <NUM> exceeds the end position of the second winding tail end E' of the second positive electrode plates <NUM>, for example, exceeding by half a ring, and the exceeded part presses inwards along a radial direction until the exceeded part is in contact with the electrode plates in the inner layer, to improve the stability of the winding structure.

The winding structure described above can simultaneously reduce the steps formed by the first positive electrode plates <NUM> and the second positive electrode plates <NUM> at the first winding initial end S and the first winding tail end E, and reduce the steps formed by the first negative electrode plates <NUM> and the second negative electrode plates <NUM> at the second winding initial end S' and the second winding tail end E', so as to reduce local stress exerted onto the electrode plate at the winding initial end and the winding tail end after the electrode assembly expands and is in contact with the housing <NUM>, prevent cracking of the electrode plate or falling off of the active substance, and improve the reliability of long-term operation of the electrode assembly.

Moreover, the number of layers of the winding structure in different radial directions can be the same, for the cylindrical winding structure, when the electrode assembly expands and is in contact with the housing <NUM>, the stress on each point along the circumferential direction is consistent.

<FIG> is a structural schematic diagram showing that a cylindrical electrode assembly is vertical to the cross section of the winding axis K in another embodiment of the present disclosure. The electrode assembly <NUM> comprises a first negative electrode plate <NUM>, a second negative electrode plate <NUM>, a first positive electrode plate <NUM>, a second positive electrode plate <NUM> and a plurality of separators <NUM>, wherein the first negative electrode plate <NUM>, the first positive electrode plate <NUM>, the second negative electrode plate <NUM> and the second positive electrode plate <NUM> are superimposed alternately in sequence, and the first negative electrode plate <NUM> is separated from the first positive electrode plate <NUM> through a separator <NUM>, the first positive electrode plate <NUM> is separated from the second negative electrode plate <NUM> through another separator <NUM>, the second negative electrode plate <NUM> is separated from the second positive electrode plate <NUM> through another separator <NUM>, and all the first negative electrode plates <NUM>, the second negative electrode plates <NUM>, the first positive electrode plates <NUM>, the second positive electrode plates <NUM> and the plurality of separators <NUM> are superimposed and then wound around a winding axis K to form a flat winding structure.

The structure of the electrode assembly <NUM> of the present embodiment is substantially similar to the structure of the electrode assembly <NUM> described in the embodiment of <FIG>, and the differences will be described below. In the winding structure of the present embodiment, the innermost ring in the winding structure is a ring enclosed jointly by the first negative electrode plates <NUM> and the second negative electrode plates <NUM>, and the outermost ring of the winding structure is a ring enclosed jointly by the first negative electrode plates <NUM> and the second negative electrode plates <NUM>.

Along a winding direction, the second negative electrode plate <NUM> is arranged at the outermost layer and the end position of the second winding tail end E' exceeds the end position of the second winding tail end E' of the first negative electrode plate <NUM>, and the end position of the second winding tail end E' of the second positive electrode plate <NUM> exceeds the end position of the second winding tail end E' of the first positive electrode plate <NUM>, for example, exceeding by half a ring.

The winding structure described above can simultaneously reduce the steps formed by the first positive electrode plate <NUM> and the second positive electrode plate <NUM> at the first winding initial end S and the first winding tail end E, and reduce the steps formed by the first negative electrode plate <NUM> and the second negative electrode plate <NUM> at the second winding initial end S' and the second winding tail end E', so as to reduce local stress exerted onto the electrode plate at the winding initial end and the winding tail end after the electrode assembly expands and is in contact with the housing <NUM>, prevent cracking of the electrode plate or falling off of the active substance, and improve the reliability of long-term operation of the electrode assembly.

In addition, this structure can avoid bending of the outermost layer of electrode plates and the penultimate layer of electrode plates at the winding tail end of other electrode plates, such that all the layers of electrode plates are in reliable contact, and no local stress is easily produced on the electrode plates, thereby preventing cracking of the electrode plate or falling off of the active substance.

Secondly, the present disclosure further provides a manufacturing method of an electrode assembly, in some embodiments, the flow diagram as shown in <FIG> comprises:.

In the present embodiment, through setting a plurality of first electrode plates <NUM>, the number of winding turns of the electrode assembly <NUM> can be reduced, then the amount of misplacement of the first tab <NUM> on the circumferential direction after winding can be reduced, and connection with the collector component <NUM> is facilitated.

Finally, the present disclosure further provides a manufacturing device <NUM> of the electrode assembly, in some embodiments, as shown in <FIG>, the manufacturing device <NUM> comprises:.

Claim 1:
An electrode assembly (<NUM>), comprising: a plurality of first electrode plates (<NUM>), at least one second electrode plate (<NUM>) and a separator (<NUM>), wherein the polarity of the first electrode plate is opposite to the polarity of the second electrode plate, the plurality of first electrode plates (<NUM>), the at least one second electrode plate (<NUM>) and the separator (<NUM>) are wound around a winding axis (K) to form a winding structure, in the winding structure, the plurality of first electrode plates (<NUM>), the at least one second electrode plate (<NUM>) and the separator (<NUM>) are arranged in a superimposing manner along a direction vertical to the winding axis, the separator is arranged between any adjacent one first electrode plate and one electrode plate and the separator is configured to separate the adjacent first electrode plate from the second electrode plate;
each first electrode plate in the plurality of first electrode plates (<NUM>) comprises a first current collector (<NUM>) and a first active substance layer (<NUM>) arranged on a superimposing surface of the first current collector, and the first current collector comprises a first main body portion (<NUM>) provided with the first active substance layer and at least one first tab (<NUM>) which protrudes from the first main body portion along the direction of the winding axis; and
wherein the first tab and the first main body portion are arranged in parallel along the winding axis, and the positions of the winding initial ends of at least two first electrode plates in the plurality of first electrode plates are different, and the winding initial ends of at least two first electrode plates are arranged in a staggered manner in the circumferential direction of the winding structure.