Electrode assembly and its related battery, device, manufacturing method and manufacturing device

Abstract

An electrode assembly (10, 120, 130, 140, 150, 160, 170, 180, 190, 200) and its associated battery (400), device, manufacturing method and manufacturing device (500), wherein the electrode assembly (10, 120, 130, 140, 150, 160, 170, 180, 190, 200) comprises: a plurality of first electrode sheets (1) and at least one second electrode sheet (2) arranged in a stack, the first electrode sheets (1) and the second electrode sheet (2) being opposite in polarity, the plurality of first electrode sheets (1) comprising a first electrode sheet (11) and a second electrode sheet (12), wherein the first electrode sheet (11) comprises a first current collector (111) and the second electrode sheet (12) comprises a second current collector (121), the first current collector (111) and the second current collector (121) being different.

Description

Technical Field

[0001] This application relates to the field of batteries, specifically to an electrode assembly and related batteries, devices, manufacturing methods, and manufacturing apparatus. Background Technology

[0002] Lithium-ion batteries have advantages such as small size, high energy density, high power density, high cycle life, and long storage time. They are widely used in electronic devices, electric vehicles, electric toys, and electric equipment. For example, lithium-ion batteries are widely used in mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools.

[0003] With the continuous development of lithium-ion battery technology, higher requirements are being placed on the performance of lithium-ion batteries, and it is hoped that lithium-ion batteries can take into account multiple design factors at the same time.

[0004] Currently, due to the limitations of the electrode assembly structure, the current collectors of the same type of electrode can only be designed with the same material or structure. Therefore, the flexibility in designing electrode assemblies is poor, and the selection of current collectors can only be based on the main design objectives, making it difficult to improve the overall performance of the battery. Summary of the Invention

[0005] This application proposes an electrode assembly and related batteries, devices, manufacturing methods, and manufacturing apparatus, which overcome or at least partially solve the above-mentioned problems.

[0006] According to a first aspect of this application, an electrode assembly is provided, comprising:

[0007] Multiple first-type electrodes and at least one second-type electrode are stacked together, with the first-type and second-type electrodes having opposite polarities.

[0008] Multiple first-type electrodes include a first electrode and a second electrode.

[0009] The first electrode includes a first current collector, and the second electrode includes a second current collector. The first current collector and the second current collector are different.

[0010] In some embodiments, the first current collector includes a first conductive layer and a protective layer disposed along a surface perpendicular to the superposition of the first electrode and the second electrode, wherein the resistivity of the protective layer is greater than the resistivity of the first conductive layer.

[0011] In some embodiments, the protective layer consists of two layers, which are respectively disposed on both sides of the first conductive layer.

[0012] In some embodiments, the protective layer is made of at least one of the following: a polymer matrix, a conductive material, and an inorganic filler.

[0013] In some embodiments, the polymer matrix includes at least one of the following: a polyvinylidene fluoride polymer matrix and a polyvinylidene chloride polymer matrix.

[0014] In some embodiments, the first conductive layer consists of two layers, which are respectively disposed on both sides of the protective layer.

[0015] In some embodiments, the protective layer is an insulating layer.

[0016] In some embodiments, the material of the protective layer includes at least one of the following: organic polymer insulating materials, inorganic insulating materials, and composite materials.

[0017] In some embodiments, the second current collector is composed of a second conductive layer.

[0018] In some embodiments, the first conductive layer and the second conductive layer are made of the same material.

[0019] In some embodiments, both the first conductive layer and the second conductive layer are made of metal.

[0020] In some embodiments, the thickness of the first conductive layer is less than or equal to the thickness of the second conductive layer.

[0021] In some embodiments, the thickness difference between the first current collector and the second current collector does not exceed μm.

[0022] In some embodiments, the outermost electrode of the electrode assembly is the first electrode.

[0023] According to a second aspect of this application, a battery is provided, comprising:

[0024] shell; and

[0025] The electrode assembly in the above embodiment is disposed inside the housing.

[0026] According to a third aspect of this application, a battery module is provided, comprising: a battery according to the plurality of claims.

[0027] According to a fourth aspect of this application, a battery pack is provided, comprising: a plurality of battery modules according to the above embodiments.

[0028] According to a fifth aspect of this application, an apparatus for using a battery is provided, comprising: the battery of the above embodiments, wherein the battery is used to provide electrical energy.

[0029] According to a sixth aspect of this application, a method for manufacturing an electrode assembly is provided, comprising:

[0030] Provide multiple first-type electrodes and at least one second-type electrode, wherein the first-type electrodes and the second-type electrodes have opposite polarities, the multiple first-type electrodes include first electrodes and second electrodes, the first electrodes include a first current collector, the second electrodes include a second current collector, and the first current collector and the second current collector are different;

[0031] Multiple first-type electrodes and at least one second-type electrode are stacked together.

[0032] According to a seventh aspect of this application, an apparatus for manufacturing an electrode assembly is provided, comprising:

[0033] An electrode placement mechanism is configured to provide multiple first-type electrodes and at least one second-type electrode, wherein the first-type electrode and the second-type electrode have opposite polarities, the multiple first-type electrodes include first electrode sheets and second electrode sheets, the first electrode sheet includes a first current collector, the second electrode sheet includes a second current collector, and the first current collector and the second current collector are different; and

[0034] The electrode stacking mechanism is configured to stack multiple first-type electrodes and at least one second-type electrode.

[0035] The electrode assembly of this application embodiment includes multiple first-type electrode sheets, each containing a first electrode sheet and a second electrode sheet with different current collectors. This allows for the selection of different current collectors for multiple first-type electrode sheets with the same polarity, based on various battery requirements. This improves the flexibility of electrode assembly electrode sheet configuration, integrates the advantages of different current collectors into the same electrode assembly, thereby balancing the performance of the electrode assembly in various aspects and improving the overall performance of the battery. Attached Figure Description

[0036] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0037] Figure 1 This is a schematic diagram of the exterior of some embodiments of a vehicle employing the battery described in this application;

[0038] Figure 2 These are schematic diagrams illustrating the structure of some embodiments of the battery pack in this application;

[0039] Figure 3 These are schematic diagrams illustrating the structure of some embodiments of the battery module of this application;

[0040] Figure 4 These are exploded views of some embodiments of the battery in this application;

[0041] Figure 5 These are side views of some embodiments of the electrode assembly of this application after being flattened;

[0042] Figure 6 These are schematic diagrams illustrating the structure of some embodiments of the electrode assembly of this application;

[0043] Figure 7 These are schematic diagrams illustrating the structure of some embodiments of the first electrode in the electrode assembly of this application;

[0044] Figure 8 These are cross-sectional views of some embodiments of the second electrode in the electrode assembly of this application;

[0045] Figure 9 These are schematic diagrams illustrating the structure of some embodiments of the second type of electrode in the electrode assembly of this application;

[0046] Figure 10 These are cross-sectional views of some embodiments of the first electrode in the electrode assembly of this application;

[0047] Figure 11 and Figure 12 They are respectively Figure 7 AA cross-sectional views of the two embodiments shown;

[0048] Figure 13 These are cross-sectional views of some embodiments of the second electrode in the electrode assembly of this application;

[0049] Figure 14 , Figure 15 , Figure 16 , Figure 17 and Figure 18 These are cross-sectional views of the first, second, third, fourth, and fifth embodiments of the flat electrode assembly of this application, respectively, in a plane perpendicular to the winding axis.

[0050] Figure 19 , Figure 20 , Figure 21 and Figure 22 These are cross-sectional views of the first, second, third, and fourth embodiments of the cylindrical electrode assembly of this application, respectively, in a plane perpendicular to the winding axis.

[0051] Figure 23 This is a schematic flowchart of some embodiments of the electrode assembly manufacturing method of this application;

[0052] Figure 24 This is a schematic flowchart of some other embodiments of the electrode assembly manufacturing method of this application;

[0053] Figure 25 The diagram shows the structure of some embodiments of the manufacturing apparatus for the electrode assembly of this application.

[0054] Figure 26 These are schematic diagrams illustrating the structure of some other embodiments of the manufacturing apparatus for the electrode assembly of this application. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0056] Unless otherwise defined, 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 pertains; the terminology used herein in the specification is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application, are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, not to describe a particular order or hierarchy.

[0057] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0058] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0059] In this application, "multiple" refers to two or more (including two), and similarly, "multiple groups" refers to two or more (including two), and "multiple pieces" refers to two or more (including two).

[0060] The electrode assemblies and their manufacturing methods, batteries, battery modules, and battery packs described in the embodiments of this application are applicable to various battery-using devices, such as mobile phones, portable devices, laptops, electric vehicles, electric cars, ships, spacecraft, electric toys, and power tools, etc. For example, spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers.

[0061] The electrode assemblies and their manufacturing methods, batteries, battery modules, and battery packs described in the embodiments of this application are not limited to the devices described above, but can also be applied to all devices that use batteries. However, for the sake of brevity, the following embodiments are all illustrated using electric vehicles as examples.

[0062] For example, such as Figure 1 The diagram shown is a structural schematic of a vehicle 100 according to an embodiment of this application. The vehicle 100 can be a gasoline vehicle, a natural gas vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery pack 200 can be installed inside the vehicle 100, for example, at the bottom, front, or rear of the vehicle. The battery pack 200 can be used to power the vehicle 100. For example, the battery pack 200 can serve as the operating power source for the vehicle 100's electrical system, such as meeting the power requirements for starting, navigation, and operation. In another embodiment of this application, the battery pack 200 can not only serve as the operating power source for the vehicle 100 but also as the driving power source, replacing or partially replacing gasoline or natural gas to provide driving power for the vehicle 100.

[0063] To meet different power demands, the battery pack 200 may include one or more battery modules, wherein the multiple battery modules may be connected in series, parallel, or a combination thereof, with the latter referring to a mixture of series and parallel connections. For example, as... Figure 2The diagram shown is a structural schematic of a battery pack 200 according to another embodiment of this application. The battery pack 200 includes a first housing 201, a second housing 202, and a plurality of battery modules 300. The shapes of the first housing 201 and the second housing 202 are determined according to the combined shape of the plurality of battery modules 300. Both the first housing 201 and the second housing 202 have an opening. For example, both the first housing 201 and the second housing 202 can be hollow cuboids and each has only one face as an opening, that is, this face does not have a housing wall so that the inside and outside of the housing are connected. The first housing 201 and the second housing 202 are fastened together at the opening to form a closed outer shell of the battery pack 200. The plurality of battery modules 300 are connected in parallel, in series, or in a mixed combination and placed inside the outer shell formed by the fastening of the first housing 201 and the second housing 202.

[0064] In another embodiment of this application, when the battery pack 200 includes a battery module 300, the battery module 300 is placed inside the outer shell formed by the first housing 201 and the second housing 202 being fastened together.

[0065] The electricity generated by the one or more battery modules 300 is led out through the housing via a conductive mechanism (not shown).

[0066] Depending on different power requirements, the battery module 300 may include one or more batteries, such as... Figure 3 As shown, the battery module 300 includes multiple batteries 400, which can be connected in series, parallel, or mixed connections to achieve a larger capacity or power. For example, the batteries 400 may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, or magnesium-ion batteries, but are not limited to these. The batteries 400 may be cylindrical, flat, cuboid, or other shapes.

[0067] In another embodiment of this application, multiple batteries 400 can be stacked together, and the multiple batteries 400 can be connected in series, in parallel or in a mixed manner. In another embodiment of this application, each battery 400 can be square, cylindrical or other shapes.

[0068] For example, such as Figure 4The diagram shown is a structural schematic of a battery 400 according to another embodiment of this application. The battery 400 includes one or more electrode assemblies 10, a housing 20, and an end cap assembly 40. The housing 20 is shaped according to the combination of the one or more electrode assemblies 10. For example, the housing 20 can be a hollow cuboid, cube, or cylinder, and one side of the housing 20 has an opening so that one or more electrode assemblies 10 can be placed inside the housing 20. For example, when the housing 20 is a hollow cuboid or cube, one plane of the housing 20 is the opening, that is, this plane does not have a housing wall, allowing communication between the inside and outside of the housing 20. When the housing 20 is a hollow cylinder, the circular side of the housing 20 is the opening, that is, this circular side does not have a housing wall, allowing communication between the inside and outside of the housing 20. The end cap assembly 40 is connected to the housing 20 at the opening to form a closed outer shell for placing the battery 400, and the housing 20 is filled with electrolyte.

[0069] The end cap assembly 40 includes an end cap 41 and two terminals 42. The end cap 41 is basically flat. The two terminals 42 are located on the flat surface of the end cap 41 and pass through the flat surface of the end cap 41. The two terminals 42 are a positive terminal and a negative terminal, respectively. Each terminal 42 is provided with a current collector 30. The current collector 30 is located between the end cap 41 and the electrode assembly 10.

[0070] For example, Figure 4 As shown, each electrode assembly 10 has a first type of tab 112' and a second type of tab 211'. The first type of tab 112' of the one or more electrode assemblies 10 is connected to a first terminal through a current collector 30, and the second type of tab 211' of the one or more electrode assemblies 10 is connected to a second terminal through another current collector 30.

[0071] In another embodiment of this application, an explosion-proof valve 43 may also be provided on the flat surface of the end cap 41. The explosion-proof valve 43 may be part of the flat surface of the end cap 41 or welded to the flat surface of the end cap 41. For example, the explosion-proof valve 43 has a groove, the depth of which is less than the thickness of the explosion-proof valve 43 in other areas except for the groove, so as not to penetrate the flat surface of the end cap 41. That is, under normal conditions, the explosion-proof valve 43 is sealed to the end cap 41. The end cap assembly 40 is connected to the housing 20 through the end cap 41 at the opening of the housing 20 to form a shell for placing the battery 400. The space formed by the shell is sealed and airtight. Inside the shell, when the battery 400 produces too much gas, the gas expands and the gas pressure inside the shell rises to a value exceeding a preset value. The explosion-proof valve 43 cracks at the groove, causing communication between the inside and outside of the shell. The gas is released outward through the crack of the explosion-proof valve 43, thereby preventing an explosion.

[0072] In this battery 400, depending on actual usage requirements, the electrode assembly 10 can be configured as a single unit or multiple units, such as... Figure 4 As shown, at least two independent electrode assemblies 10 are provided inside the battery 400.

[0073] In this battery 400, the electrode assembly 10 can be a wound structure or a stacked structure. The following embodiments will be described using the wound structure of the electrode assembly 10 as an example.

[0074] In another embodiment of this application, the electrode assembly 10 has a wound structure, such as... Figure 5 As shown, the electrode assembly 10 may include: multiple first type electrode sheets 1 and at least one second type electrode sheet 2 stacked together, the first type electrode sheet 1 and the second type electrode sheet 2 having opposite polarities, and the multiple first type electrode sheets 1 including a first electrode sheet 11 and a second electrode sheet 12.

[0075] For example, multiple first-type electrodes 1 can be at least two positive electrodes, and correspondingly, at least one second-type electrode 2 can be at least one negative electrode; or, multiple first-type electrodes 1 can be at least two negative electrodes, and correspondingly, at least one second-type electrode 2 can be at least one positive electrode. The multiple first-type electrodes 1 can be 2, 3, or 4, and the at least one second-type electrode 2 can be 1, 2, 3, or 4, etc.

[0076] In another embodiment of this application, each first type of electrode 1 and each second type of electrode 2 have substantially the same shape. For example, after the wound structure is flattened, the first type of electrode 1 and the second type of electrode 2 are essentially long strips, for example, long strips 5-20 meters long. The lengths of the first type of electrode 1 and the second type of electrode 2 differ within a predetermined range, and their widths are substantially the same. Figure 6 As shown, a winding structure can be obtained by stacking multiple first-type electrode sheets 1 and at least one second-type electrode sheet 2 along the long strip direction. The winding structure has a winding axis K, and the stacking surface of the at least one positive electrode sheet 1 and at least one negative electrode sheet 2 is basically parallel to the winding axis K.

[0077] In another embodiment of this application, the stacking of multiple first-type electrode sheets 1 and at least one second-type electrode sheet 2 can take various forms. For example, when the multiple first-type electrode sheets 1 consist of two or more first-type electrode sheets 1, and the at least one second-type electrode sheet 2 consists of one or more second-type electrode sheets 2, the winding structure, after being flattened, can be stacked alternately in the form of one first-type electrode sheet 1 and one second-type electrode sheet 2, or alternately in the form of every two or more first-type electrode sheets 1 and one second-type electrode sheet 2, or alternately in the form of one first-type electrode sheet 1 and every two or more second-type electrode sheets 2. The stacking of multiple first-type electrode sheets 1 and multiple second-type electrode sheets 2 can also be understood as each adjacent pair of first-type electrode sheets 1 includes at least one second-type electrode sheet 2, or each adjacent pair of second-type electrode sheets 2 includes multiple first-type electrode sheets 1.

[0078] When multiple first-type electrode sheets 1 and at least one second-type electrode sheet 2 are stacked, a separator 3 is provided between any adjacent positive electrode sheet 1 and negative electrode sheet 2 to separate the adjacent first-type electrode sheet 1 and second-type electrode sheet 2 so that the adjacent positive electrode sheet and negative electrode sheet do not short-circuit with each other.

[0079] In another embodiment of this application, adjacent electrodes of different polarities, i.e., the first type of electrode 1 and the second type of electrode 2 are adjacent, means that there are no other electrodes between the first type of electrode 1 and the second type of electrode 2 but there is at least one layer of diaphragm 3. For example, there are no other first type of electrode 1 or second type of electrode 2 between the first type of electrode 1 and the second type of electrode 2. It can also be understood that the first type of electrode 1 and the second type of electrode 2 are most directly adjacent to each other. For example, based on an electrode of a certain polarity (e.g., the first type of electrode 1), the first layer of electrodes of different polarities adjacent to the first type of electrode (e.g., the second type of electrode 2) are called adjacent electrodes.

[0080] In another embodiment of this application, two electrodes of the same polarity being adjacent means that there is only one electrode of another polarity between them. For example, two first-type electrodes 1 being adjacent means that there is only one second-type electrode 2 between them, and two second-type electrodes 2 being adjacent means that there is only one first-type electrode 1 between them. In another embodiment of this application, when there are no other electrodes of different polarities between two electrodes of the same polarity, the two electrodes of the same polarity can be regarded as one electrode.

[0081] In another embodiment of this application, when there are no other electrodes or separators of different polarities between two or more electrodes of the same polarity, the two electrodes of the same polarity can be regarded as a group of electrodes. Then, during stacking, the electrode group of the same polarity is stacked alternately with another electrode group of different polarities or a single electrode. For example, two or more positive electrodes form a positive electrode group, and two or more negative electrodes form a negative electrode group. The stacking can be: the positive electrode group and the negative electrode group are stacked alternately, the positive electrode group and the single negative electrode are stacked alternately, or the negative electrode group and the positive electrode group are stacked alternately, and the negative electrode group and the single positive electrode are stacked alternately.

[0082] Since a group of electrodes of the same polarity can be regarded as a single electrode, for the sake of convenience, the term "a single electrode" in the following description can refer to either a single electrode or a group of electrodes of the same polarity.

[0083] However, regardless of how they are stacked, at least one diaphragm 3 is provided between adjacent electrodes of different polarities.

[0084] In another embodiment of this application, the diaphragm 3 includes a diaphragm base layer and a functional layer. The diaphragm base layer can be at least one of polypropylene, polyethylene, ethylene-propylene copolymer, polybutylene terephthalate, etc., and the functional layer can be a mixture of ceramic oxide and binder. In another embodiment of this application, after the wound structure is flattened, the diaphragm 3 is a separate thin film and is essentially in the shape of a long strip, for example, a long strip 5-20 meters long. In another embodiment of this application, the diaphragm 3 is coated on the surface of the first electrode 1 or the second electrode 2, that is, the diaphragm 3 and the first electrode 1 or the second electrode 2 are an integral structure.

[0085] For ease of description, the following embodiment uses the example of a first type electrode 1 and a second type electrode 2 stacked sequentially, with a separator 3 placed between adjacent first type electrode 1 and second type electrode 2. For example, the electrode assembly 10 includes two first type electrode 1s and two second type electrode 2s. Before winding, each first type electrode 1 and each second type electrode 2 can be a long strip structure. The two first type electrode 1s and two second type electrode 2s are stacked in the thickness direction of the electrode, and a separator 3 is placed between any adjacent first type electrode 1s and second type electrode 2s. That is, a first type electrode 1 and a second type electrode 2 are stacked alternately in sequence, and a separator 3 is placed between adjacent first type electrode 1s and second type electrode 2s. The stacking plane of the two first type electrode 1s and two second type electrode 2s is substantially parallel to the winding axis K of the winding structure of the electrode assembly 10.

[0086] In the electrode assembly 10 described above, such as Figure 7 and Figure 8As shown, the plurality of first type electrodes 1 include a first electrode 11 and a second electrode 12, wherein the first electrode 11 includes a first current collector 111, and the second electrode 12 includes a second current collector 121, and the first current collector 111 and the second current collector 121 are different.

[0087] The differences between the first current collector 111 and the second current collector 121 may include at least one of the following: the first current collector 111 and the second current collector 121 have different thicknesses or shapes along the direction perpendicular to the stacking surface of the first electrode 1 and the second electrode 2; the materials and / or number of stacked layers stacked along the stacking surface perpendicular to the first electrode 1 and the second electrode 2 are different; whether or not they are perforated is different; the number of perforations is different; the range of the active material region is different; whether or not there is an insulating region between the active material region and the electrode tab is different; the range of the insulating region between the active material region and the electrode tab is different; and whether or not there is a protective layer is different, or the materials are different, etc.

[0088] In another embodiment of this application, a first active material layer 113 may be coated on the first current collector 111 and the second current collector 121. The first active material layer 113 on the first current collector 111 and the second current collector 121 may be the same or different. When the first active material layer 113 is a positive electrode active material layer, it may be a ternary material, lithium manganese oxide, or lithium iron phosphate; when the first active material layer 113 is a negative electrode active material layer, it may be graphite or silicon.

[0089] like Figure 9 As shown, the second type of electrode 2 includes a third current collector 21 and a second type of active material layer 22 coated on the third current collector 21. When the first type of active material layer 113 is a positive electrode active material layer, the second type of active material layer 22 is a negative electrode active material layer; when the first type of active material layer 113 is a negative electrode active material layer, the second type of active material layer 22 is a positive electrode active material layer.

[0090] In the electrode assembly 10 of this embodiment, multiple first-type electrode sheets 1 include first electrode sheets 11 and second electrode sheets 12 with different current collectors. Different current collectors 111 can be selected for first-type electrode sheets 1 with the same polarity according to the needs of the electrode assembly 10 in terms of process, safety or performance. This can improve the flexibility of the structure configuration of the electrode assembly 10, so as to integrate the advantages of different current collectors into the same electrode assembly 10, thereby balancing the performance of the electrode assembly 10 in many aspects and improving the overall performance of the battery 400.

[0091] In another embodiment of this application, such as Figure 10As shown, the first current collector 111 includes a first conductive layer 1111 and a protective layer 1112 stacked along the stacking surface perpendicular to the first electrode 1 and the second electrode 2. That is, the first current collector 111 adopts a multi-layer structure in the stacking direction. The first active material layer 113 is disposed on the protective layer 1112 and is in contact with it. The resistivity of the protective layer 1112 is greater than the resistivity of the first conductive layer 1111. Since the resistance of the first current collector 111 is related to resistivity, length, and cross-sectional area, by providing the protective layer 1112 with a higher resistivity, the resistance of the first current collector 111 can be increased.

[0092] When a short circuit occurs in battery 400 under abnormal conditions, the internal resistance of battery 400 will be greatly reduced due to the internal short circuit. This application increases the resistance of the first current collector 111 to increase the internal resistance of battery 400 after a short circuit, thereby improving the safety performance of battery 400. In addition, this application can control the heat generated by the short circuit within a range that battery 400 can completely absorb. Therefore, the heat generated at the point where the internal short circuit occurs can be completely absorbed by battery 400, and the temperature rise of battery 400 is very small. Thus, the impact of short circuit damage on battery 400 can be limited to a "point" range, forming only a "point open circuit". The temperature rise of battery due to short circuit heat generation is not significant and does not affect the normal use of battery in a short period of time.

[0093] In another embodiment of this application, such as Figure 10 As shown, the protective layer 1112 consists of two layers, each disposed on both sides of the conductive layer 1111, for example, on the two overlapping surfaces of the conductive layer 1111. A first active material layer 113 is provided on the side of each of the two protective layers 1112 away from the conductive layer 1111. Alternatively, the protective layer 1112 can also be a single layer disposed on one side of the conductive layer 1111, for example, on one of the overlapping surfaces of the conductive layer 1111.

[0094] For example, the protective layer 1112 is made of a polymer matrix, a conductive material, and an inorganic filler.

[0095] The polymer matrix is ​​at least one of polyvinylidene fluoride (PVDF) and polyvinylidene chloride (PVDC). The PVDF matrix material of the protective layer 1112 includes polyvinylidene fluoride (PVDF) and modified PVDF, and the PVDC includes polyvinylidene chloride (PVDC) and modified PVDC. For example, the PVDF and / or PVDC can be selected from PVDF, carboxylic acid-modified PVDF, acrylic acid-modified PVDF, PVDF copolymers, PVDC, carboxylic acid-modified PVDC, acrylic acid-modified PVDC, PVDC copolymers, or any mixture thereof.

[0096] In this embodiment, the polymer matrix serves as a positive temperature coefficient (PCT) thermistor layer, acting as both the PTC matrix and the binder. This avoids the impact on coating adhesion, PTC effect response temperature, and response speed caused by differences in the binder and PTC matrix materials. Furthermore, it facilitates the preparation of a thinner protective layer 1112 without affecting its adhesion.

[0097] Secondly, the protective layer 1112, composed of polyvinylidene fluoride and / or polyvinylidene chloride materials and conductive materials, can act as a PTC thermistor layer, with an appropriate operating temperature range of 80°C to 160°C, thus effectively improving the high-temperature safety performance of battery 400.

[0098] In addition, the solvent (such as N-methylpyrrolidone, abbreviated as NMP) or electrolyte in the first active material layer 113 on the upper layer of the protective layer 1112 can have adverse effects such as dissolution and swelling on the polymer material in the protective layer 1112. For the protective layer 1112 containing only PVDF as an adhesive, this can easily lead to poor adhesion. However, for the protective layer 1112 of this application, since the content of polyvinylidene fluoride and / or polyvinylidene chloride is relatively large, this adverse effect can be reduced.

[0099] The conductive material can be selected from at least one of conductive carbon-based materials, conductive metal materials, and conductive polymer materials. The conductive carbon-based material is selected from at least one of conductive carbon black, acetylene black, graphite, graphene, carbon nanotubes, and carbon nanofibers. The conductive metal material is selected from at least one of Al powder, Ni powder, and gold powder. The conductive polymer material is selected from at least one of conductive polythiophene, conductive polypyrrole, and conductive polyaniline. One conductive material can be used alone or in combination of two or more.

[0100] The inorganic filler may be selected from at least one of magnesium oxide, aluminum oxide, titanium dioxide, zirconium oxide, silicon dioxide, silicon carbide, boron carbide, calcium carbonate, aluminum silicate, calcium silicate, potassium titanate, barium sulfate, lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, lithium nickel manganese oxide, lithium nickel manganese cobalt oxide, lithium nickel manganese aluminum oxide, lithium iron phosphate, lithium vanadium phosphate, lithium cobalt phosphate, lithium manganese phosphate, lithium iron silicate, lithium vanadium silicate, lithium cobalt silicate, lithium manganese silicate, lithium titanate, or at least one of the above materials with conductive carbon coating modification, conductive metal coating modification, or conductive polymer coating modification.

[0101] In another embodiment of this application, such as Figure 11As shown, the conductive layer 1111 consists of two layers, each disposed on one side of the protective layer 1112, for example, on the two overlapping surfaces of the protective layer 1112. The protective layer 1112 supports the conductive layer 1111, providing support and protection for it. The conductive layer 1111 supports the first active material layer 113, providing electrons to it, thus acting as a conductor and current collector. The conductive layer 1111 may also be disposed on only one side of the protective layer 1112, for example, on one of the overlapping surfaces of the protective layer 1112.

[0102] When a short circuit occurs in battery 400 under abnormal conditions, the internal resistance of battery 400 will be greatly reduced due to the internal short circuit. This application increases the internal resistance of battery 400 after a short circuit by increasing the resistance of the first current collector 111, thereby improving the safety performance of battery 400. This application can limit the impact of short circuit damage on battery 400 to a "point" range, that is, limit the impact of short circuit damage on battery 400 to the damaged point. Furthermore, due to the high resistance of the first current collector 111, the short circuit current is greatly reduced, and the heat generated by the short circuit makes the temperature rise of the battery insignificant, which does not affect the normal use of the battery for a short period of time. This characteristic is called "point circuit breaking".

[0103] In another embodiment of this application, the protective layer 1112 can be an insulating layer. Since the density of an insulating layer is generally lower than that of a metal, the first current collector 111 of this application can improve the safety performance of the battery 400 while also increasing the gravimetric energy density of the battery 400. Moreover, since the insulating layer can provide good support and protection for the conductive layer 1111 located on its surface, it can prevent electrode breakage.

[0104] For example, the material of the protective layer 1112 may be selected from at least one of organic polymer insulating materials, inorganic insulating materials, and composite materials.

[0105] Among them, the organic polymer insulating material is preferably at least one of polyamide, polyterephthalate, polyimide, polyethylene, polypropylene, polystyrene, polyvinyl chloride, acrylonitrile-butadiene-styrene copolymer, polybutylene terephthalate, poly(p-phenylene terephthalamide), polypropylene, polyoxymethylene, epoxy resin, phenolic resin, polytetrafluoroethylene, polyvinylidene fluoride, silicone rubber, and polycarbonate.

[0106] The preferred inorganic insulating material is at least one of alumina, silicon carbide, and silicon dioxide.

[0107] The composite material is preferably at least one of epoxy resin glass fiber reinforced composite material and polyester resin glass fiber reinforced composite material.

[0108] In another embodiment of this application, such as Figure 11As shown, the thickness of the protective layer 1112 is D1, where D1 satisfies 1μm ≤ D1 ≤ 50μm. For example, the upper limit of the thickness D1 of the protective layer 1112 can be 50μm, 45μm, 40μm, 35μm, 30μm, 25μm, 20μm, 15μm, 12μm, 10μm, or 8μm, and the lower limit of the thickness D1 of the protective layer 1112 can be 1μm, 1.5μm, 2μm, 3μm, 4μm, 5μm, 6μm, or 7μm; the range of the thickness D1 of the protective layer 1112 can be composed of any value of the upper or lower limit.

[0109] Optionally, D1 satisfies: 2μm≤D1≤30μm; for example, 5μm≤D1≤20μm.

[0110] In the above embodiments, the conductive layer 1111 is made of metal. For example, the conductive metal material can be selected from at least one of aluminum, copper, nickel, titanium, silver, nickel-copper alloy, and aluminum-zirconium alloy.

[0111] In another embodiment of this application, such as Figure 11 As shown, the thickness D2 of the conductive layer 1111 satisfies: 1nm ≤ D2 ≤ 1μm. In this application, the upper limit of the thickness D2 of the conductive layer 1111 can be 1μm, 900nm, 800nm, 700nm, 600nm, 500nm, 450nm, 400nm, 350nm, 300nm, 250nm, 200nm, 150nm, 120nm, 100nm, 80nm, or 60nm, and the lower limit of the thickness D2 of the conductive layer 1111 can be 1nm, 5nm, 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, or 55nm; the range of the thickness D2 of the conductive layer 1111 can be composed of any value of the upper or lower limit.

[0112] Optionally, the thickness D2 of the conductive layer 1111 satisfies: 20nm≤D2≤500nm, for example, 50nm≤D2≤200nm.

[0113] The conductive layer 1111 is described using aluminum. If the first electrode 11 is a positive electrode, the current collector of the positive electrode is generally made of aluminum. When a short circuit occurs under abnormal battery conditions, the heat generated at the short circuit point can trigger a violent aluminothermic reaction, thereby generating a large amount of heat and causing accidents such as battery explosion. However, in this application, the first current collector 111 only uses aluminum material for the conductive layer 1111, and the amount of aluminum is only nanometer-thick. Therefore, the amount of aluminum in the first current collector 111 is greatly reduced, thus avoiding the aluminothermic reaction and significantly improving the safety performance of the battery 400.

[0114] The electrode assembly 10 may include multiple first-type electrode sheets 1 and at least one second-type electrode sheet 2. However, for ease of description, the following embodiments will be described using the example of the electrode assembly 10 including two first-type electrode sheets 1, two second-type electrode sheets 2 and multiple diaphragms 3.

[0115] The appearance of the winding structure of the electrode assembly 10 can be cylindrical, flat, elliptical, cubic, cuboid or any other shape. However, for the sake of convenience, the following description will take the winding structure of the electrode assembly 10 as a flat shape and a cylindrical shape as examples.

[0116] like Figure 14 The diagram shows a cross-sectional view of a flat electrode assembly perpendicular to the winding axis K, according to another embodiment of this application. The first electrode is a positive electrode, and the second electrode is a negative electrode. The electrode assembly 120 includes a first negative electrode 1201, a second negative electrode 1202, a first positive electrode 1203, a second positive electrode 1204, and multiple separators 1205. The first negative electrode 1201, the first positive electrode 1203, the second negative electrode 1202, and the second positive electrode 1204 are alternately stacked, and the first… The negative electrode 1201 is separated from the first positive electrode 1203 by a separator 1205. The first positive electrode 1203 and the second negative electrode 1202 are separated by another separator 1205. The second negative electrode 1202 and the second positive electrode 1204 are separated by another separator 1205. All the first negative electrode 1201, the second negative electrode 1202, the first positive electrode 1203, the second positive electrode 1204 and the multiple separators 1205 are stacked and wound around the winding axis K to form a flat winding structure.

[0117] In this embodiment, the structure and position of the positive electrode tabs of the first positive electrode 1203 and the second positive electrode 1204, and the negative electrode tabs of the first negative electrode 1201 and the second negative electrode 1202, can all refer to the aforementioned description. Figure 6-13 The relevant descriptions of the positive and negative electrode tabs in the embodiments are not repeated here.

[0118] In this embodiment, the number of electrode layers in the winding structure of the electrode assembly 120 does not differ by a preset number at different radial directions, i.e., at different positions circumferentially along the winding structure. This can also be referred to the aforementioned... Figure 6-13 The relevant content described in the embodiments will not be repeated here.

[0119] In this embodiment, the electrode assembly 120, the first negative electrode 1201 and the second negative electrode 1202 respectively include negative electrode active material regions as described above. Figure 6-13The negative electrode plate described in the embodiments includes a negative electrode active material region, and the positive electrode plate 1203 and the second positive electrode plate 1204 respectively include positive electrode active material regions as described above. Figure 6-13 The negative electrode active material region included in the positive electrode sheet described in the embodiments will not be repeated here.

[0120] In this embodiment of the electrode assembly, the first negative electrode 1201 and the second negative electrode 1202 can use different current collectors, and / or the first positive electrode 1203 and the second positive electrode 1204 can also use different current collectors. The structural form, material, thickness relationship of the current collectors for electrodes with the same polarity, and the thickness of each layer when the electrode is a multilayer structure can all be as described above. Figure 6-13 The current collectors described in the embodiments are not repeated here.

[0121] In the winding structure, the innermost ring is the ring surrounded by the first negative electrode 1201, and the outermost ring is the ring surrounded by the second negative electrode 1202.

[0122] In this embodiment, the winding structure of the electrode assembly 120 includes a flat region 10A and turning regions 10B located on both sides of the flat region 10A. The superimposed surfaces of the electrode sheets in the flat region 10A are basically parallel planes and basically parallel to the winding axis. Here, the plane is not a plane in the strict sense and a certain error is allowed. The flat region 10A includes a first sub-flat region 10A1 and a second sub-flat region 10A2 that are basically parallel and symmetrically distributed with respect to the winding axis K along a plane perpendicular to the winding axis K. The two turning regions 10B are located on both sides of the flat region 10A formed by the combination of the first sub-flat region 10A1 and the second sub-flat region 10A2.

[0123] The first winding start S of the first positive electrode 1203 and the second positive electrode 1204 are in the same position. For example, the first winding start S of the first positive electrode 1203 and the second positive electrode 1204 are both located in the sub-straight region (e.g., the first sub-straight region 10A1) on the same side of the straight region 10A, and the first winding start S of the first positive electrode 1203 and the second positive electrode 1204 are flush.

[0124] The second winding start point S' of the first negative electrode 1201 and the second negative electrode 1202 are also in the same position. For example, the second winding start point S' of the first negative electrode 1201 and the second negative electrode 1202 are both located in the sub-straight region (e.g., the first sub-straight region 10A1) on the same side of the straight region 10A, and the second winding start point S' of the first negative electrode 1201 and the second negative electrode 1202 are flush.

[0125] In the opposite direction of the winding direction, the second winding start S' of the first negative electrode 1201 extends beyond the first winding start S of the first positive electrode 1204. The second winding start S' of the second negative electrode 1202 extends beyond the first winding start S of the second positive electrode 1203.

[0126] The first winding ends E of the first positive electrode 1203 and the second positive electrode 1204 are at the same position. For example, the first winding ends E of the first positive electrode 1203 and the second positive electrode 1204 are both located in the same turning area (e.g., the first turning area 10B1), and the first winding ends E of the first positive electrode 1203 and the second positive electrode 1204 are flush.

[0127] The second winding ends E' of the first negative electrode 1201 and the second negative electrode 1202 are also in the same position. For example, the second winding ends E' of the first negative electrode 1201 and the second negative electrode 1202 are both located in the same turning area (e.g., the first turning area 10B1), and are also located in the same turning area (e.g., the first turning area 10B1) as the first winding ends E of the first positive electrode 1203 and the second positive electrode 1204, and the second winding ends E' of the first negative electrode 1201 and the second negative electrode 1202 are flush.

[0128] Along the winding direction, the second winding end E' of the first negative electrode 1201 extends beyond the first winding end E of the second positive electrode 1204, and the second winding end E' of the second negative electrode 1202 extends beyond the first winding end E of the first positive electrode 1203.

[0129] The winding structure of the electrode assembly described above enables the length differences of multiple electrode sheets to be close before winding, making it easy to wind.

[0130] like Figure 15 The diagram shows a cross-section of a flat electrode assembly perpendicular to the winding axis K, according to another embodiment of this application. The first electrode is a positive electrode, and the second electrode is a negative electrode. The electrode assembly 130 includes a first negative electrode 1301, a second negative electrode 1302, a first positive electrode 1303, a second positive electrode 1304, and multiple separators 1305. The first negative electrode 1301, the first positive electrode 1303, the second negative electrode 1302, and the second positive electrode 1304 are alternately stacked, and the first… The negative electrode 1301 is separated from the first positive electrode 1303 by a separator 1305. The first positive electrode 1303 and the second negative electrode 1302 are separated by another separator 1305. The second negative electrode 1302 and the second positive electrode 1304 are separated by another separator 1305. All the first negative electrode 1301, the second negative electrode 1302, the first positive electrode 1303, the second positive electrode 1304 and the multiple separators 1305 are stacked and wound around the winding axis K to form a flat winding structure.

[0131] In this embodiment of the electrode assembly, the first negative electrode 1301 and the second negative electrode 1302 can use different current collectors, and / or the first positive electrode 1303 and the second positive electrode 1304 can also use different current collectors. The structural form, material, thickness relationship of the current collectors for electrodes with the same polarity, and the thickness of each layer when the electrode is a multilayer structure can all be as described above. Figure 6-13 The current collectors described in the embodiments are not repeated here.

[0132] The structure of the electrode assembly 130 in this embodiment is similar to... Figure 14 The electrode assemblies described in the embodiments have basically similar structures, with the differences being as follows.

[0133] In the winding structure of the electrode assembly 130 in this embodiment, the innermost ring of the winding structure is the ring surrounded by the first negative electrode 1301, and the outermost ring of the winding structure is the ring jointly surrounded by the first negative electrode 1301 and the second negative electrode 1302.

[0134] The first winding end E of the first positive electrode 1303 and the second positive electrode 1304 are at different positions. For example, the first winding end E of the first positive electrode 1303 and the second positive electrode 1304 are located in the second turning region 10B2 and the first turning region 10B1, respectively.

[0135] The positions of the second winding ends E' of the first negative electrode 1301 and the second negative electrode 1302 are also different. For example, the second winding ends E' of the first negative electrode 1301 and the second negative electrode 1302 are located in the first turning area 10B1 and the second turning area 10B2, respectively.

[0136] Along the winding direction, the second winding end E' of the first negative electrode 1301 extends beyond the first winding end E of the second positive electrode 1304, and the second winding end E' of the second negative electrode 1302 extends beyond the first winding end E of the first positive electrode 1303.

[0137] The winding structure of the electrode assembly described above can reduce the step formed by the first positive electrode 1303 and the second positive electrode 1304 at the first winding end E, and reduce the step formed by the first negative electrode 1301 and the second negative electrode 1302 at the second winding end E'. This reduces the local stress on the electrode at the winding end after the electrode assembly contacts the housing when it expands, preventing the electrode from breaking or the active material from falling off, and improving the reliability of the electrode assembly during long-term operation.

[0138] like Figure 16The diagram shows a cross-section of a flat electrode assembly perpendicular to the winding axis K, according to another embodiment of this application. The first electrode is a positive electrode, and the second electrode is a negative electrode. The electrode assembly 140 includes a first negative electrode 1401, a second negative electrode 1402, a first positive electrode 1403, a second positive electrode 1404, and multiple separators 1405. The first negative electrode 1401, the first positive electrode 1403, the second negative electrode 1402, and the second positive electrode 1404 are alternately stacked, and the first… The negative electrode 1401 is separated from the first positive electrode 1403 by a separator 1405. The first positive electrode 1403 and the second negative electrode 1402 are separated by another separator 1405. The second negative electrode 1402 and the second positive electrode 1404 are separated by another separator 1405. All the first negative electrode 1401, the second negative electrode 1402, the first positive electrode 1403, the second positive electrode 1404 and the multiple separators 1405 are stacked and wound around the winding axis K to form a flat winding structure.

[0139] In this embodiment of the electrode assembly, the first negative electrode 1401 and the second negative electrode 1402 can use different current collectors, and / or the first positive electrode 1403 and the second positive electrode 1404 can also use different current collectors. The structural form, material, thickness relationship of the current collectors for electrodes with the same polarity, and the thickness of each layer when the electrode is a multilayer structure can all be as described above. Figure 6-13 The current collectors described in the embodiments are not repeated here.

[0140] The structure of the electrode assembly 140 in this embodiment is similar to... Figure 14 The electrode assemblies described in the embodiments have basically similar structures, with the differences being as follows.

[0141] In the winding structure of the electrode assembly 140 in this embodiment, the innermost ring of the winding structure is the ring surrounded by the first negative electrode 1401, and the outermost ring of the winding structure is the ring surrounded by the second negative electrode 1402.

[0142] In the winding structure of the electrode assembly in this embodiment, the second winding ends E' of the first negative electrode 1401 and the second negative electrode 1402 are not in the same position. For example, the second winding ends E' of the first negative electrode 1401 and the second negative electrode 1402 are both located in the same turning area (e.g., the first turning area 10B1), and the second winding ends E' of the first negative electrode 1401 and the second negative electrode 1402 are not aligned.

[0143] The winding structure of the electrode assembly 140 described above can reduce the difference in the number of electrode layers between the first sub-flat region 10A1 and the second sub-flat region 10A2. When the electrode assembly expands and comes into contact with the housing, the inner wall of the housing applies a reaction force to the two planes of the electrode assembly, which can make the stress on the electrode sheets of the first sub-flat region 10A1 and the second sub-flat region 10A2 more consistent.

[0144] like Figure 17 The diagram shows a cross-section of a flat electrode assembly perpendicular to the winding axis K, according to another embodiment of this application. The first electrode is a positive electrode, and the second electrode is a negative electrode. The electrode assembly 150 includes a first negative electrode 1501, a second negative electrode 1502, a first positive electrode 1503, a second positive electrode 1504, and multiple separators 1505. The first negative electrode 1501, the first positive electrode 1503, the second negative electrode 1502, and the second positive electrode 1504 are alternately stacked, and the first… The negative electrode 1501 is separated from the first positive electrode 1503 by a separator 1505. The first positive electrode 1503 and the second negative electrode 1502 are separated by another separator 1505. The second negative electrode 1502 and the second positive electrode 1504 are separated by another separator 1505. All the first negative electrode 1501, the second negative electrode 1502, the first positive electrode 1503, the second positive electrode 1504 and the multiple separators 1505 are stacked and wound around the winding axis K to form a flat winding structure.

[0145] In this embodiment of the electrode assembly, the first negative electrode 1501 and the second negative electrode 1502 can use different current collectors, and / or the first positive electrode 1503 and the second positive electrode 1504 can also use different current collectors. The structural form, material, thickness relationship of the current collectors for electrodes with the same polarity, and the thickness of each layer when the electrode is a multilayer structure can all be as described above. Figure 6-13 The current collectors described in the embodiments are not repeated here.

[0146] The structure of the electrode assembly 150 in this embodiment is similar to... Figure 14 The electrode assemblies described in the embodiments are basically similar in structure, with the differences as follows. In the winding structure of the electrode assembly in this embodiment, the innermost ring of the winding structure is the ring jointly surrounded by the first negative electrode 1501 and the second negative electrode 1502, and the outermost ring of the winding structure is the ring surrounded by the second negative electrode 1502.

[0147] In the winding structure of the electrode assembly 150 in this embodiment, the first winding start ends S of the first positive electrode 1503 and the second positive electrode 1504 are at different positions. For example, the first winding start ends S of the first positive electrode 1503 and the second positive electrode 1504 are located in the first sub-flat region 10A1 and the second sub-flat region 10A2, respectively, and the first winding start ends S of the first positive electrode 1503 and the second positive electrode 1504 are not flush.

[0148] The positions of the second winding start ends S of the first negative electrode 1501 and the second negative electrode 1502 are also different. For example, the second winding start ends S of the first negative electrode 1501 and the second negative electrode 1502 are located in the first sub-straight region 10A1 and the second sub-straight region 10A2, respectively, and the second winding start ends S of the first negative electrode 1501 and the second negative electrode 1502 are not aligned.

[0149] The winding structure of the electrode assembly described above can reduce the step formed by the first positive electrode 1503 and the second positive electrode 1504 at the first winding start end S, and reduce the step formed by the first negative electrode 1501 and the second negative electrode 1502 at the second winding start end S'. This reduces the local stress at the winding start end after the electrode assembly contacts the housing 20 when it expands, preventing the electrode from breaking or the active material from falling off, and improving the reliability of the electrode assembly during long-term operation.

[0150] like Figure 18 The diagram shows a cross-section of a flat electrode assembly perpendicular to the winding axis K, according to another embodiment of this application. The first electrode is a positive electrode, and the second electrode is a negative electrode. The electrode assembly 160 includes a first negative electrode 1601, a second negative electrode 1602, a first positive electrode 1603, a second positive electrode 1604, and multiple separators 1605. The first negative electrode 1601, the first positive electrode 1603, the second negative electrode 1602, and the second positive electrode 1604 are alternately stacked, and the first… The negative electrode 1601 is separated from the first positive electrode 1603 by a separator 1605. The first positive electrode 1603 and the second negative electrode 1602 are separated by another separator 1605. The second negative electrode 1602 and the second positive electrode 1604 are separated by another separator 1605. All the first negative electrode 1601, the second negative electrode 1602, the first positive electrode 1603, the second positive electrode 1604 and the multiple separators 1605 are stacked and wound around the winding axis K to form a flat winding structure.

[0151] In this embodiment of the electrode assembly, the first negative electrode 1601 and the second negative electrode 1602 can use different current collectors, and / or the first positive electrode 1603 and the second positive electrode 1604 can also use different current collectors. The structural form, material, thickness relationship of the current collectors for electrodes with the same polarity, and the thickness of each layer when the electrode is a multilayer structure can all be as described above. Figure 6-13 The current collectors described in the embodiments are not repeated here.

[0152] The structure of the electrode assembly 160 in this embodiment is similar to... Figure 14 The electrode assemblies described in the embodiments are basically similar in structure, with the differences as follows. In the winding structure of the electrode assembly in this embodiment, the innermost ring of the winding structure is the ring jointly surrounded by the first negative electrode 1601 and the second negative electrode 1602, and the outermost ring of the winding structure is the ring jointly surrounded by the first negative electrode 1601 and the second negative electrode 1602.

[0153] In the winding structure of the electrode assembly 160 in this embodiment, the first winding start ends S of the first positive electrode 1603 and the second positive electrode 1604 are at different positions. For example, the first winding start ends S of the first positive electrode 1603 and the second positive electrode 1604 are located in the first sub-flat region 10A1 and the second sub-flat region 10A2, respectively, and the first winding start ends S of the first positive electrode 1603 and the second positive electrode 1604 are not flush.

[0154] The positions of the second winding start ends S' of the first negative electrode 1601 and the second negative electrode 1602 are also different. For example, the second winding start ends S' of the first negative electrode 1601 and the second negative electrode 1602 are located in the first sub-straight region 10A1 and the second sub-straight region 10A2, respectively, and the second winding start ends S' of the first negative electrode 1601 and the second negative electrode 1602 are not aligned.

[0155] The first winding ends E of the first positive electrode 1603 and the second positive electrode 1604 are at different positions. For example, the first winding ends E of the first positive electrode 1603 and the second positive electrode 1604 are located in different turning areas 10B. Furthermore, the first winding ends E of the first positive electrode 1303 and the second positive electrode 1304 are not aligned.

[0156] The positions of the second winding ends E' of the first negative electrode 1601 and the second negative electrode 1602 are also different. For example, the second winding ends E' of the first negative electrode 1601 and the second negative electrode 1602 are located in two different turning areas 10B. Furthermore, the second winding ends E' of the first negative electrode 1601 and the second negative electrode 1602 are not aligned.

[0157] The winding structure of the electrode assembly described above can simultaneously reduce the steps formed by the first positive electrode 1603 and the second positive electrode 1604 at the first winding start S and the first winding end E, and reduce the steps formed by the first negative electrode 1601 and the second negative electrode 1602 at the second winding start S' and the second winding end E'. This reduces the local stress on the electrode assembly at the winding start and winding end after it comes into contact with the housing 20 when it expands, preventing the electrode from breaking or the active material from falling off, and improving the reliability of the electrode assembly during long-term operation.

[0158] Based on the above embodiments, the number of electrode layers does not differ by a preset number in different radial directions of the winding structure, i.e., at different positions circumferentially around the winding structure. Here, the number of electrode layers refers to the total number of positive and negative electrode layers. The preset number of layers is less than or equal to the sum of the number of positive and negative electrode sheets.

[0159] When the electrode assembly expands and comes into contact with the housing 20, the housing 20 applies a reaction force to the electrode assembly, which makes the force on the electrode assembly more uniform in all directions and prevents large performance differences in different parts of the electrode assembly during use. For example, two positive electrode sheets and two layers of negative electrode sheets are set, with a preset number of layers less than or equal to four. The smaller the difference in the number of electrode sheets, the more uniform the force on the electrode assembly in all directions.

[0160] like Figure 14-18 As shown, both the outermost and innermost layers of the wound structure are negative electrode sheets. The positive electrode active material in the positive electrode sheet is generally a ternary material, lithium manganese oxide, or lithium iron phosphate, while the negative electrode active material in the negative electrode sheet is generally graphite or silicon. Since the positive electrode active material is more expensive than the negative electrode active material, having both the outermost and innermost layers of the wound structure covered by negative electrode sheets allows for full utilization of the positive electrode active material, improving the energy efficiency of the wound structure and reducing the manufacturing difficulty of the electrode assembly.

[0161] Optionally, at least one of the outermost and innermost layers of the wound structure is a positive electrode. In order to reduce the manufacturing cost of the electrode assembly, the positive electrode active material can be omitted from the surface of the positive electrode that is away from the negative electrode for the outermost or innermost positive electrode.

[0162] Figures 19 to 22 A schematic diagram of the cylindrical electrode assembly is shown.

[0163] like Figure 19The diagram shows a cross-section of a cylindrical electrode assembly perpendicular to the winding axis K, according to another embodiment of this application. The first electrode is a positive electrode, and the second electrode is a negative electrode. The electrode assembly 170 includes a first negative electrode 1701, a second negative electrode 1702, a first positive electrode 1703, a second positive electrode 1704, and multiple separators 1705. The first negative electrode 1701, the first positive electrode 1703, the second negative electrode 1702, and the second positive electrode 1704 are alternately stacked, and the first… The negative electrode 1701 is separated from the first positive electrode 1703 by a separator 1705. The first positive electrode 1703 and the second negative electrode 1702 are separated by another separator 1705. The second negative electrode 1702 and the second positive electrode 1704 are separated by another separator 1705. All the first negative electrode 1701, the second negative electrode 1702, the first positive electrode 1703, the second positive electrode 1704 and the multiple separators 1705 are stacked and wound around the winding axis K to form a cylindrical winding structure.

[0164] In this embodiment, the structure and position of the positive electrode tabs of the first positive electrode 1703 and the second positive electrode 1704, and the negative electrode tabs of the first negative electrode 1701 and the second negative electrode 1702, can all refer to the aforementioned description. Figure 6-13 The relevant descriptions of the positive and negative electrode tabs in the embodiments are not repeated here.

[0165] In this embodiment, the number of electrode layers does not differ by a preset number at different radial directions of the winding structure, i.e., at different positions circumferentially along the winding structure. This can also be referred to the aforementioned... Figure 6-13 The relevant content described in the embodiments will not be repeated here.

[0166] In this embodiment, the electrode assembly 170, the first negative electrode 1701 and the second negative electrode 1702 respectively include negative electrode active material regions as described above. Figure 6-13 The negative electrode plate described in the embodiments includes a negative electrode active material region, and the positive electrode plate 1703 and the second positive electrode plate 1704 respectively include positive electrode active material regions as described above. Figure 6-13 The negative electrode active material region included in the positive electrode sheet described in the embodiments will not be repeated here.

[0167] In this embodiment of the electrode assembly, the first negative electrode 1701 and the second negative electrode 1702 can use different current collectors, and / or the first positive electrode 1703 and the second positive electrode 1704 can also use different current collectors. The structural form, material, thickness relationship of the current collectors for electrodes with the same polarity, and the thickness of each layer when the electrode is a multilayer structure can all be as described above. Figure 6-13 The current collectors described in the embodiments are not repeated here.

[0168] In the winding structure, the innermost ring is the ring surrounded by the first negative electrode 1701, and the outermost ring is the ring surrounded by the second negative electrode 1702.

[0169] The first winding start end S of the first positive electrode 1703 and the second positive electrode 1704 are in the same position. For example, the first winding start end S of the first positive electrode 1703 and the second positive electrode 1704 are both located on the same radial direction of the winding structure, and the first winding start end S of the first positive electrode 1703 and the second positive electrode 1704 are flush.

[0170] The second winding start point S' of the first negative electrode 1701 and the second negative electrode 1702 are also in the same position. For example, the second winding start point S' of the first negative electrode 1701 and the second negative electrode 1702 are both located on the same radial direction of the winding structure, and the second winding start point S' of the first negative electrode 1701 and the second negative electrode 1702 are flush.

[0171] In the opposite direction of the winding direction, the second winding start S' of the first negative electrode 1701 extends beyond the first winding start S of the first positive electrode 1704. The second winding start S' of the second negative electrode 1702 extends beyond the first winding start S of the second positive electrode 1703.

[0172] The first winding ends E of the first positive electrode 1703 and the second positive electrode 1704 are at the same position. For example, the first winding ends E of the first positive electrode 1703 and the second positive electrode 1704 are both located in the turning area 10B on the same side, and the first winding ends E of the first positive electrode 1703 and the second positive electrode 1704 are flush.

[0173] The second winding ends E' of the first negative electrode 1701 and the second negative electrode 1702 are also in the same position. For example, the second winding ends E' of the first negative electrode 1701 and the second negative electrode 1702 are both located in the same turning area 10B, and the second winding ends E' of the first negative electrode 1701 and the second negative electrode 1702 are flush.

[0174] Along the winding direction, the second winding end E' of the first negative electrode 1701 extends beyond the first winding end E of the second positive electrode 1704, and the second winding end E' of the second negative electrode 1702 extends beyond the first winding end E of the first positive electrode 1703.

[0175] The winding structure described above enables the length differences of multiple electrodes to be close before winding, making winding easier.

[0176] like Figure 20The diagram shows a cross-section of a cylindrical electrode assembly perpendicular to the winding axis K, according to another embodiment of this application. The first electrode is a positive electrode, and the second electrode is a negative electrode. The electrode assembly 180 includes a first negative electrode 1801, a second negative electrode 1802, a first positive electrode 1803, a second positive electrode 1804, and multiple separators 1805. The first negative electrode 1801, the first positive electrode 1803, the second negative electrode 1802, and the second positive electrode 1804 are alternately stacked, and the first… The negative electrode 1801 is separated from the first positive electrode 1803 by a separator 1805. The first positive electrode 1803 and the second negative electrode 1802 are separated by another separator 1805. The second negative electrode 1802 and the second positive electrode 1804 are separated by another separator 1805. All the first negative electrode 1801, the second negative electrode 1802, the first positive electrode 1803, the second positive electrode 1804 and the multiple separators 1805 are stacked and wound around the winding axis K to form a cylindrical winding structure.

[0177] In this embodiment of the electrode assembly, the first negative electrode 1801 and the second negative electrode 1802 can use different current collectors, and / or the first positive electrode 1803 and the second positive electrode 1804 can also use different current collectors. The structural form, material, thickness relationship of the current collectors for electrodes with the same polarity, and the thickness of each layer when the electrode is a multilayer structure can all be as described above. Figure 6-13 The current collectors described in the embodiments are not repeated here.

[0178] The structure described in this embodiment and Figure 19 The structures described in the embodiments are basically similar, with the differences as follows. In the winding structure of this embodiment, the innermost ring of the winding structure is the ring jointly surrounded by the first negative electrode 1801 and the second negative electrode 1802, and the outermost ring of the winding structure is the ring surrounded by the first negative electrode 1801.

[0179] In the winding structure of this embodiment, the first winding start ends S of the first positive electrode 1803 and the second positive electrode 1804 are at different positions. For example, the first winding start ends S of the first positive electrode 1803 and the second positive electrode 1804 are located on opposite radial directions of the winding structure, and the first winding start ends S of the first positive electrode 1803 and the second positive electrode 1804 are not aligned.

[0180] The positions of the second winding start ends S of the first negative electrode 1801 and the second negative electrode 1802 are also different. For example, the second winding start ends S' of the first negative electrode 1801 and the second winding start ends S' of the second negative electrode 1802 are located on the opposite radial side of the winding structure, and the second winding start ends S' of the first negative electrode 1801 and the second negative electrode 1802 are not aligned.

[0181] The winding structure described above can reduce the steps formed by the first positive electrode 1803 and the second positive electrode 1804 at the first winding start end S, and reduce the steps formed by the first negative electrode 1801 and the second negative electrode 1802 at the second winding start end S'. This reduces the local stress at the winding start end after contact with the shell 20 during expansion, preventing electrode breakage or active material shedding, and improving the reliability of long-term operation.

[0182] like Figure 21 The diagram shows a cross-section of a cylindrical electrode assembly perpendicular to the winding axis K, according to another embodiment of this application. The first electrode is a positive electrode, and the second electrode is a negative electrode. The electrode assembly 190 includes a first negative electrode 1901, a second negative electrode 1902, a first positive electrode 1903, a second positive electrode 1904, and multiple separators 1905. The first negative electrode 1901, the first positive electrode 1903, the second negative electrode 1902, and the second positive electrode 1904 are alternately stacked, and the first negative electrode 1905... The electrode 1901 is separated from the first positive electrode 1903 by a separator 1905. The first positive electrode 1903 and the second negative electrode 1902 are separated by another separator 1905. The second negative electrode 1902 and the second positive electrode 1904 are separated by another separator 1905. All the first negative electrode 1901, the second negative electrode 1902, the first positive electrode 1903, the second positive electrode 1904 and the multiple separators 1905 are stacked and wound around the winding axis K to form a flat winding structure.

[0183] In this embodiment, the electrode assembly can use different current collectors for the first negative electrode 1901 and the second negative electrode 1902, and / or different current collectors for the first positive electrode 1903 and the second positive electrode 1904. The structural form, material, thickness relationship of the current collectors for electrodes with the same polarity, and the thickness of each layer when the electrode is a multilayer structure can all be as described above. Figure 6-13 The current collectors described in the embodiments are not repeated here.

[0184] The structure described in this embodiment and Figure 20 The structures described in the embodiments are basically similar, with the differences as follows. In the winding structure of this embodiment, the innermost ring of the winding structure is the ring jointly surrounded by the first negative electrode 1901 and the second negative electrode 1902, and the outermost ring of the winding structure is the ring surrounded by the first negative electrode 1901.

[0185] In the winding structure of this embodiment, the first winding end E of the first positive electrode 1903 and the second positive electrode 1904 are at different positions, and the second winding end E' of the first negative electrode 1901 and the second negative electrode 1902 are also at different positions.

[0186] Along the winding direction, the first negative electrode 1901 is located on the outermost layer, and the end position of the second winding end E' extends beyond the end position of the second winding end E' of the second negative electrode 1902. The end position of the second winding end E' of the first positive electrode 1903 extends beyond the end position of the second winding end E' of the second positive electrode 1904. For example, it extends beyond half a turn, and the excess portion is pressed radially inward to contact the inner electrode to improve the stability of the winding structure.

[0187] The winding structure described above can simultaneously reduce the steps formed by the first positive electrode 1903 and the second positive electrode 1904 at the first winding start S and the first winding end E, and reduce the steps formed by the first negative electrode 1901 and the second negative electrode 1902 at the second winding start S' and the second winding end E'. This reduces the local stress at the winding start and winding end after contact with the shell 20 during expansion, preventing electrode breakage or active material shedding and improving long-term operational reliability.

[0188] Moreover, this method can achieve the same number of layers in different radial directions. For cylindrical winding structures, it can make the stress along the circumference more consistent when expansion occurs and the structure comes into contact with the shell 20.

[0189] like Figure 22 The diagram shows a cross-section of a cylindrical electrode assembly perpendicular to the winding axis K, according to another embodiment of this application. The first electrode is a positive electrode, and the second electrode is a negative electrode. The electrode assembly 200 includes a first negative electrode 2001, a second negative electrode 2002, a first positive electrode 2003, a second positive electrode 2004, and multiple separators 2005. The first negative electrode 2001, the first positive electrode 2003, the second negative electrode 2002, and the second positive electrode 2004 are alternately stacked, and the first negative electrode... The electrode 2001 is separated from the first positive electrode 2003 by a separator 2005. The first positive electrode 2003 and the second negative electrode 2002 are separated by another separator 2005. The second negative electrode 2002 and the second positive electrode 2004 are separated by another separator 2005. All the first negative electrode 2001, the second negative electrode 2002, the first positive electrode 2003, the second positive electrode 2004 and the multiple separators 2005 are stacked and wound around the winding axis K to form a flat winding structure.

[0190] In this embodiment of the electrode assembly, the first negative electrode 2001 and the second negative electrode 2002 can use different current collectors, and / or the first positive electrode 2003 and the second positive electrode 2004 can also use different current collectors. The structural form, material, thickness relationship of the current collectors for electrodes with the same polarity, and the thickness of each layer when the electrode is a multilayer structure can all be as described above. Figure 6-13The current collectors described in the embodiments are not repeated here.

[0191] The structure described in this embodiment and Figure 20 The structures described in the embodiments are basically similar, with the differences as follows. In the winding structure of this embodiment, the innermost ring of the winding structure is the ring jointly surrounded by the first negative electrode 2001 and the second negative electrode 2002, and the outermost ring of the winding structure is the ring jointly surrounded by the first negative electrode 2001 and the second negative electrode 2002.

[0192] Along the winding direction, the second negative electrode 2002 is located on the outermost layer, and the end position of the second winding end E' exceeds the end position of the second winding end E' of the first negative electrode 2001. The end position of the second winding end E' of the second positive electrode 2004 exceeds the end position of the second winding end E' of the first positive electrode 2003. For example, it exceeds half a turn.

[0193] The winding structure described above can simultaneously reduce the steps formed by the first positive electrode 2003 and the second positive electrode 2004 at the first winding start S and the first winding end E, and reduce the steps formed by the first negative electrode 2001 and the second negative electrode 2002 at the second winding start S' and the second winding end E'. This reduces the local stress at the winding start and winding end after contact with the shell 20 during expansion, preventing electrode breakage or active material shedding and improving long-term operational reliability.

[0194] Moreover, this method can achieve the same number of layers in different radial directions. For cylindrical winding structures, it can make the stress along the circumference more consistent when expansion occurs and the structure comes into contact with the shell 20.

[0195] In addition, this structure can prevent the outermost and penultimate electrode layers from bending at the winding ends of other electrode layers, ensuring reliable contact between the electrode layers and preventing localized stress on the electrode, thereby preventing electrode breakage or loss of active material.

[0196] Secondly, this application also provides a method for manufacturing an electrode assembly. In another embodiment of this application, such as... Figure 23 The flowchart shown includes:

[0197] Step 101: Provide multiple first type electrode sheets 1 and at least one second type electrode sheet 2, wherein the first type electrode sheet 1 and the second type electrode sheet 2 have opposite polarities, the multiple first type electrode sheets 1 include a first electrode sheet 11 and a second electrode sheet 12, the first electrode sheet 11 includes a first current collector 111, the second electrode sheet 12 includes a second current collector 121, and the first current collector 111 and the second current collector 121 are different;

[0198] Step 102: Stack multiple first-type electrode sheets 1 and at least one second-type electrode sheet 2.

[0199] Step 102 is executed after step 101. In step 101, specifically, multiple first-type electrode sheets 1, multiple diaphragms 3, and multiple second-type electrode sheets 2 are stacked in the thickness direction of the electrode sheets. The multiple first-type electrode sheets 1 and multiple second-type electrode sheets 2 are alternately arranged in a piece-by-piece manner, and the diaphragm 3 is located between adjacent first-type electrode sheets 1 and second-type electrode sheets 2.

[0200] In this embodiment, according to the various needs of the electrode assembly 10, the electrodes with the same polarity can be designed to contain different current collectors, so as to improve the flexibility of the structure configuration of the electrode assembly 10, integrate the advantages of different current collectors into the same electrode assembly 10, thereby balancing the performance of the electrode assembly 10 in various aspects and improving the overall performance of the battery 400.

[0201] In another embodiment of this application, the electrode assembly 10 is a wound electrode assembly, and after step 102, as follows: Figure 24 The process diagram shown further illustrates that the manufacturing method of electrode assembly 10 includes:

[0202] Step 103: Multiple first-type electrode sheets 1 and at least one second-type electrode sheet 2 are wound around the winding axis K to form a winding structure, wherein, in the winding structure, the first-type electrode sheets 1 and the second-type electrode sheets 2 are alternately arranged in a direction perpendicular to the winding axis K.

[0203] Finally, this application also provides an electrode assembly manufacturing apparatus 500, in another embodiment of this application, such as... Figure 25 As shown, it includes: an electrode placement mechanism 501 and an electrode stacking mechanism 502.

[0204] The electrode placement mechanism 501 is configured to provide multiple first-type electrode sheets 1 and at least one second-type electrode sheet 2, wherein the first-type electrode sheet 1 and the second-type electrode sheet 2 have opposite polarities, the multiple first-type electrode sheets 1 include a first electrode sheet 11 and a second electrode sheet 12, the first electrode sheet 11 includes a first current collector 111, the second electrode sheet 12 includes a second current collector 121, and the first current collector 111 and the second current collector 121 are different;

[0205] The electrode stacking mechanism 502 is configured to stack multiple first-type electrodes 1 and at least one second-type electrode 2.

[0206] The electrode assembly 10 produced by the electrode assembly manufacturing apparatus 500 can be designed to include different current collectors by having electrodes of the same polarity according to various battery requirements, thereby improving the flexibility of the structure configuration of the electrode assembly 10, integrating the advantages of different current collectors into the same electrode assembly, thereby balancing the performance of the electrode assembly 10 in various aspects, and thus improving the overall performance of the battery 400.

[0207] In another embodiment of this application, such as Figure 26 As shown, the electrode assembly 10 is a wound electrode assembly. The manufacturing apparatus 500 of the electrode assembly may further include a winding mechanism 503, configured to wind multiple first-type electrode sheets 1 and multiple second-type electrode sheets 2 around a winding axis K to form a winding structure. In the winding structure, the first-type electrode sheets 1 and the second-type electrode sheets 2 are alternately arranged in a direction perpendicular to the winding axis K. The winding mechanism 503 can provide stable winding tension for the electrode sheets.

[0208] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features. However, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. An electrode assembly, comprising: The system comprises multiple first-type electrodes and at least one second-type electrode stacked together, wherein the first-type electrodes and the second-type electrodes have opposite polarities. The multiple first-type electrodes include first-type electrodes and second-type electrodes with the same polarity. The first-type electrodes include a first current collector, and the second-type electrodes include a second current collector. The first current collector and the second current collector are different. The first current collector includes a first conductive layer and a protective layer stacked along a surface perpendicular to the stacking plane of the first-type electrodes and the second-type electrodes. The resistivity of the protective layer is greater than the resistivity of the first conductive layer. The second current collector is composed of a second conductive layer, and the thickness of the first conductive layer is less than the thickness of the second conductive layer. The first conductive layer and the second conductive layer are made of the same material.

2. The electrode assembly according to claim 1, wherein, The protective layer consists of two layers, which are respectively disposed on both sides of the first conductive layer.

3. The electrode assembly according to claim 2, wherein, The protective layer is made of at least one of the following materials: a polymer matrix, a conductive material, and an inorganic filler.

4. The electrode assembly according to claim 3, wherein, The polymer matrix includes at least one of the following: polyvinylidene fluoride polymer matrix and polyvinylidene chloride polymer matrix.

5. The electrode assembly according to claim 1, wherein, The first conductive layer consists of two layers, which are respectively disposed on both sides of the protective layer.

6. The electrode assembly according to claim 5, wherein, The protective layer is an insulating layer.

7. The electrode assembly according to claim 5, wherein, The material of the protective layer includes at least one of the following: organic polymer insulating materials, inorganic insulating materials, and composite materials.

8. The electrode assembly according to any one of claims 1 to 7, wherein, Both the first conductive layer and the second conductive layer are made of metal.

9. The electrode assembly according to any one of claims 1 to 7, wherein, The thickness difference between the first current collector and the second current collector does not exceed 5 μm.

10. The electrode assembly according to any one of claims 1 to 7, wherein, The outermost electrode of the electrode assembly is the first electrode.

11. A battery, comprising: case; and The electrode assembly according to any one of claims 1 to 10, wherein the electrode assembly is disposed within the housing.

12. A battery module, comprising: The battery as described in several claims 11.

13. A battery pack, comprising: The battery module as described in several claims 12.

14. A device using a battery, comprising: The battery of claim 11, wherein the battery is used to provide electrical energy.

15. A method for manufacturing an electrode assembly, comprising: A plurality of first-type electrodes and at least one second-type electrode are provided, wherein the first-type electrode and the second-type electrode have opposite polarities. The plurality of first-type electrodes include first and second electrodes with the same polarity. The first electrode includes a first current collector, and the second electrode includes a second current collector. The first current collector and the second current collector are different. The first current collector includes a first conductive layer and a protective layer stacked along a surface perpendicular to the stacking plane of the first-type electrode and the second-type electrode. The resistivity of the protective layer is greater than the resistivity of the first conductive layer. The second current collector is composed of a second conductive layer. The thickness of the first conductive layer is less than the thickness of the second conductive layer; The plurality of first-type electrodes and the at least one second-type electrode are stacked together; The first conductive layer and the second conductive layer are made of the same material.

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