Electrode assembly, battery cell, battery, and electrical device

Abstract

The present application relates to the technical field of batteries, and particularly to an electrode assembly, a battery cell, a battery, and an electrical device. The electrode assembly includes a first current collector provided with a first coating area and a second coating area. The first coating area is used for coating an active material, and the second coating area is used for coating a lithium supplement material. Moreover, a first interval is provided between the first coating area and the second coating area. The electrode assembly can perform lithium supplementation during the charge-discharge cycle and avoid the phenomena of lithium plating and regional over-lithium supplementation during the lithium supplementation process, so as to further improve the lithium supplementation effect and ensure the safety performance of the battery.

Description

Technical Field

[0001] The present application relates to the field of batteries, and particularly to an electrode assembly, a battery cell, a battery, and an electrical device. Background Art

[0002] With the continuous development of new energy technologies, people have higher and higher requirements for battery technologies. For example, in order to stabilize the capacity of a battery cell, it is usually necessary to supplement lithium ions to the battery cell to make the lithium ion content in the electrolyte sufficient, so as to achieve the purpose of enabling the battery cell to have a stable capacity. Therefore, how to better supplement lithium ions to the battery cell to make the battery cell have a stable capacity has become an urgent problem to be solved in this field. Summary of the Invention

[0003] In view of the above problems, embodiments of the present application provide an electrode assembly, a battery cell, a battery, and an electrical device, which can make the capacitance more stable.

[0004] An embodiment of the first aspect of the present application provides an electrode assembly. The electrode assembly includes a first current collector, the first current collector includes a first coating area and a second coating area, the first coating area is coated with an active material, the second coating area is coated with a lithium supplement material, and a first interval is provided between the first coating area and the second coating area along the extending direction of the first current collector.

[0005] By adopting the above solution, when the electrode assembly undergoes charge and discharge reactions, the lithium supplement material in the second coating area can precipitate lithium ions into the electrolyte to make up for the number of lithium ions consumed during the formation of the solid electrolyte membrane, so that the lithium ion content in the electrolyte remains sufficient, thereby keeping the battery capacity stable. In addition, this structure can also avoid direct contact between the lithium supplement material and the active material during the charge and discharge process of the electrode assembly, thus preventing problems such as lithium precipitation and uneven lithium intercalation, and further improving the lithium supplement effect.

[0006] In some embodiments, the electrode assembly further includes a second current collector. The first current collector and the second current collector are wound to form the electrode assembly. Along the winding direction of the electrode assembly, the first current collector includes an extending portion that extends beyond the second current collector, and the second coating area is located in the extending portion.

[0007] By adopting the above solution, the second coating area is located in the extending portion, so that the lithium supplement material and the active material are respectively located at both ends of the first current collector along the winding direction, and only one material switching is required during the process of coating the first current collector to complete the coating process of the lithium supplement material and the active material, which is convenient for processing, can reduce the process, and improve the processing efficiency; moreover, setting the lithium supplement material on a partial area of the first current collector that extends beyond the second current collector can avoid the phenomenon that the lithium supplement material faces the active material on the second current collector, resulting in lithium precipitation or poor lithium supplement effect.

[0008] In some embodiments, the first spacer is at least partially located in the extension portion.

[0009] By adopting the above solution, it is avoided that the lithium supplement material coated on the extension portion is partially opposite to the active material coated on the second current collector, so as to avoid the generation of lithium deposition; in addition, part of the first spacer is located in the extension portion. When the first current collector is a positive current collector, part of the first spacer is located on the first current collector outside the extension portion, so that the region coated with the active material on the second current collector can extend along the winding direction beyond the region coated with the active material on the first current collector; when the first current collector is a negative current collector, the first spacer can be completely located in the extension portion, so that the region coated with the active material on the first current collector can extend along the winding direction beyond the region coated with the active material on the second current collector. In this way, it is beneficial to provide sufficient lithium insertion sites for the positive active material, thereby improving the cycle performance of the battery.

[0010] In some embodiments, the first current collector includes at least two first coating regions, and a second coating region is provided between two adjacent first coating regions.

[0011] By adopting the above solution, the second coating region is arranged in the middle of two adjacent first coating regions, and a first spacer is arranged between the first coating region and the second coating region. In this way, after the lithium supplement material replenishes lithium ions to the nearby electrolyte, the lithium ions in the electrolyte can diffuse to the negative active material on both sides and finally reach the lithium insertion sites. Since the lithium ions in the electrolyte can diffuse to the lithium insertion sites on both sides, the overall distance for all lithium ions that need to be inserted into the negative active material to reach all lithium insertion positions can be shortened, and the overall lithium supplement efficiency can be improved.

[0012] In some embodiments, the electrode assembly further includes at least two second current collectors. The first current collector and the second current collectors are wound to form the electrode assembly. A second spacer is provided between two adjacent second current collectors, and the second coating region is arranged opposite to the second spacer.

[0013] By adopting the above solution, when the first current collector is a positive current collector, it can be avoided that the lithium supplement material coated on the second coating region is opposite to the blank second current collector, or it can be avoided that the lithium supplement material coated on the second coating region is opposite to the negative active material coated on the second current collector, so as to further avoid the lithium deposition of lithium ions in the electrolyte on the blank current collector, or further avoid the poor overall lithium supplement effect due to the increase in the total amount of the negative active material.

[0014] In some embodiments, the electrode assembly further includes a second current collector. The first current collector and the second current collector are wound to form the electrode assembly. A third coating area and a fourth coating area are provided on the second current collector. A third interval is provided between the third coating area and the fourth coating area, and the second coating area is disposed opposite to the third interval.

[0015] By adopting the above solution, when the first current collector is a negative current collector, it is possible to prevent the lithium supplement material coated on the second coating area from facing the positive electrode active material layer coated on the second current collector, so as to avoid the precipitation of lithium ions released from the positive electrode active material on the surface of the lithium supplement material, resulting in lithium precipitation.

[0016] In some embodiments, the size of the first interval along the extending direction of the first current collector is greater than or equal to 1 mm.

[0017] By adopting the above solution, it is possible to avoid the contact between the active material coated on the first coating area and the lithium supplement material coated on the second coating area, thereby avoiding phenomena such as lithium precipitation and over-lithium supplementation in the region.

[0018] In some embodiments, the first current collector includes a first surface and a second surface opposite to each other in its thickness direction, and the second coating area is located on the first surface and / or the second surface.

[0019] By adopting the above solution, the coating area of the second coating area can be set according to the lithium supplementation requirement. Both surfaces of the first current collector in the thickness direction can be used for coating the lithium supplement material, or one of them can be used for coating the lithium supplement material and the other for coating the active material, which can make the layout of the lithium supplement material more flexible.

[0020] An embodiment of the second aspect of the present application further provides a battery cell, including the electrode assembly in any of the above embodiments.

[0021] An embodiment of the third aspect of the present application further provides a battery, including the battery cell provided by the embodiment of the second aspect of the present application.

[0022] An embodiment of the fourth aspect of the present application further provides an electrical device, including the battery provided by the third aspect of the present application, and the battery is used to provide electrical energy.

[0023] The above description is only an overview of the technical solutions of the embodiments of the present application. In order to be able to understand the technical means of the embodiments of the present application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the embodiments of the present application more obvious and understandable, the specific embodiments of the present application are hereinafter specifically exemplified. Description of the Drawings

[0024] Other features, objects, and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings, in which like or similar reference numerals denote like or similar features.

[0025] Figure 1 FIG. 4 is a schematic structural diagram of a vehicle provided by an embodiment of the present application;

[0026] Figure 2 FIG. 8 is an explosion schematic diagram of a battery provided by some embodiments of the present application;

[0027] Figure 3 FIG. 12 is an explosion schematic diagram of a battery cell provided by some embodiments of the present application;

[0028] Figure 4 FIG. 16 is a schematic structural diagram of an electrode assembly provided by some embodiments of the present application;

[0029] Figure 5 FIG. 20 is a schematic structural diagram of a first current collector and a second current collector after unfolding provided by some embodiments of the present application;

[0030] Figure 6 FIG. 24 is a schematic structural diagram of a first current collector and a second current collector after unfolding provided by some other embodiments of the present application;

[0031] Figure 7 FIG. 28 is a schematic structural diagram of an electrode assembly provided by some other embodiments of the present application;

[0032] Figure 8 FIG. 32 is a schematic structural diagram of an electrode assembly provided by some other embodiments of the present application;

[0033] Figure 9 FIG. 36 is a schematic structural diagram of a first current collector provided by some embodiments of the present application.

[0034] Description of reference numerals:

[0035] 1 - Vehicle;

[0036] 2 - Battery;

[0037] 3 - Controller;

[0038] 4 - Motor;

[0039] 5 - Box body, 51 - First box body part, 52 - Second box body part, 53 - Accommodating space;

[0040] 6 - Battery cell;

[0041] 61 - Electrode assembly;

[0042] 611 - First fluid collector, 611a - First coating area, 611b - Second coating area, 611c - First interval, 611d - Extension part;

[0043] 612 - Second fluid collector, 612a - Third coating area, 612b - Fourth coating area, 612c - Third interval;

[0044] 613 - Second interval;

[0045] 62 - Housing;

[0046] 63 - End cap;

[0047] X - Extension direction of the first fluid collector, Y - Thickness direction of the first fluid collector;

[0048] A1 - First surface;

[0049] A2 - Second surface. Detailed implementation manners

[0050] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly described below with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are some, but not all, of the embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of this application without creative efforts shall fall within the protection scope of this application.

[0051] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by those skilled in the technical field to which this application belongs; the terms used in the description of this application in the specification are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification, claims, and drawings of this application are intended to cover non-exclusive inclusion. The terms "first", "second", etc. in the specification, claims, or drawings of this application are used to distinguish different objects and are not used to describe a specific order or primary-secondary relationship.

[0052] Referring to "embodiments" in this application means that specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of this application. The phrase appears in various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments.

[0053] In the description of the present application, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", "attachment" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a direct connection or an indirect connection through an intermediate medium, and it may be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0054] In the present application, the term "and / or" is merely a description of the relationship between associated objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the present application, the character " / " generally represents an "or" relationship between the associated objects before and after.

[0055] In the embodiments of the present application, the same reference numerals represent the same components. And for the sake of brevity, in different embodiments, the detailed description of the same components is omitted. It should be understood that the thickness, length, width and other dimensions of various components shown in the drawings in the embodiments of the present application, as well as the overall thickness, length, width and other dimensions of the integrated device are only for illustrative purposes and should not constitute any limitation to the present application.

[0056] The term "a plurality of" appearing in the present application means two or more (including two).

[0057] During the charge and discharge process of the battery cell after it is manufactured, a solid electrolyte film will be formed. The solid electrolyte film is a passivation film layer with the properties of a solid electrolyte. This layer of film can be an excellent conductor of lithium ions in the battery cell, allowing lithium ions to be transported therein so that lithium ions can enter the surface of graphite through it for lithium deintercalation and intercalation work. At the same time, this layer of film can also be an electronic insulator, used to reduce the short-circuit probability inside the battery cell to improve self-discharge. In addition, this layer of film can also effectively prevent the co-insertion of solvent molecules, avoiding the damage to the electrode material caused by the co-insertion of solvent molecules, and thus can improve the cycle performance and service life of the electrode material.

[0058] However, during the formation process of the solid electrolyte film, part of the lithium ions will be consumed, resulting in a decrease in the lithium ion content in the electrolyte, an increase in the irreversible capacity during the charge and discharge process, a reduction in the charge and discharge efficiency of the electrode material, and a decline in the performance of the battery cell.

[0059] Based on this, some existing battery cells usually add a lithium supplementing material. When the solid electrolyte membrane is formed and consumes a part of lithium ions, the lithium supplementing material can supplement the content of lithium ions in the electrolyte to reduce or even avoid irreversible capacity loss during the charge and discharge process of the battery cell. In the existing battery cell structures containing lithium supplementing materials, some separate the lithium supplementing material from the electrode assembly by using a separator membrane. In this structure, not only is the process complex, requiring additional processing of the separator membrane for separating the lithium supplementing material and the electrode assembly, but also additional electrical connection needs to be made to the lithium supplementing material, resulting in poor reliability and being prone to affecting the lithium supplementing effect. To solve these problems, contemporary technicians design to coat, spray, or vapor deposit a layer of lithium supplementing material on the surface of the negative electrode sheet. However, due to the uneven thickness of the active material coated on the negative electrode sheet itself, it is also difficult to control the uniformity of the lithium supplementing material during coating. When the lithium supplementing material is unevenly coated on the surface of the negative electrode sheet, it is easy to cause over-lithium supplementation in some areas and insufficient lithium supplementation in other areas. The remaining lithium supplementing material in the over-lithium supplementation areas will continuously stay on the surface of the electrode sheet and prevent other lithium ions from embedding, ultimately resulting in the appearance of lithium dendrites on the surface of the electrode sheet. The growth of lithium dendrites will pierce the separator membrane, thus affecting the safety performance of the battery cell, while insufficient lithium supplementation in some areas makes the lithium supplementing effect unsatisfactory.

[0060] Based on this, the present application provides an electrode assembly, which includes a first current collector. The first current collector includes a first coating area and a second coating area. The first coating area is used for coating an active material, and the second coating area is used for coating a lithium supplementing material, and a gap is provided between the first coating area and the second coating area. In this way, the second coating area can continuously precipitate lithium ions into the electrolyte to keep the content of lithium ions in the electrolyte sufficient when the battery cell is charged and discharged. In this way, while achieving the lithium supplementing effect, the appearance of lithium precipitation can be avoided, and the performance of the battery cell can be improved.

[0061] The electrode assembly described in the embodiments of the present application is applicable to battery cells, batteries containing such battery cells, and electrical devices using the batteries.

[0062] The electrical device can be a vehicle, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, etc. The vehicle can be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range electric vehicle, etc.; the spacecraft includes an airplane, a rocket, a space shuttle, a spaceship, etc.; the electric toy includes a stationary or mobile electric toy, for example, a game console, an electric vehicle toy, an electric ship toy, an electric airplane toy, etc.; the electric tool includes a metal cutting electric tool, a grinding electric tool, an assembly electric tool and a railway electric tool, for example, an electric drill, an electric grinding wheel, an electric wrench, an electric screwdriver, a hammer drill, an impact drill, a concrete vibrator, a planer, etc. The embodiments of the present application do not impose special restrictions on the above electrical devices.

[0063] For the convenience of description, the following embodiments take the electrical device as a vehicle as an example for description.

[0064] Please refer to Figure 1 , Figure 1 which is a schematic structural diagram of the vehicle 1 provided by some embodiments of the present application. As Figure 1 shown, a battery 2 is disposed inside the vehicle 1. The battery 2 refers to a single physical module including one or more battery cells to provide a higher voltage and capacity. For example, the battery mentioned in the present application may include a battery module or a battery pack, etc. The battery 2 can be disposed at the bottom, the head or the tail of the vehicle 1. The battery 2 can be used to supply power to the vehicle 1. For example, the battery 2 can be used as the operating power source of the vehicle 1. The vehicle 1 may further include a controller 3 and a motor 4. The controller 3 is used to control the battery 2 to supply power to the motor 4, for example, for the working power requirements during the start, navigation and driving of the vehicle 1.

[0065] In some embodiments of the present application, the battery 2 can not only be used as the operating power source of the vehicle 1, but also be used as the driving power source of the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0066] Please refer to Figure 2 , Figure 2 which is an explosion schematic diagram of the battery 2 provided by some embodiments of the present application. As Figure 2 shown, the battery 2 includes a box body 5 and battery cells 6, and the battery cells 6 are accommodated in the box body 5.

[0067] The housing 5 is used to accommodate battery cells 6, and the housing 5 can be of various structures. In some embodiments, the housing 5 may include a first housing part 51 and a second housing part 52. The first housing part 51 and the second housing part 52 cover each other, and the first housing part 51 and the second housing part 52 jointly define an accommodation space 53 for accommodating the battery cells. The second housing part 52 can be a hollow structure with one end open, and the first housing part 51 is a plate-like structure. The first housing part 51 covers the open side of the second housing part 52 to form the housing 5 with the accommodation space 53. Both the first housing part 51 and the second housing part 52 can also be hollow structures with one side open, and the open side of the first housing part 51 covers the open side of the second housing part 52 to form the housing 5 with the accommodation space 53. Of course, the first housing part 51 and the second housing part 52 can be of various shapes, such as a cylinder, a cuboid, etc.

[0068] To improve the sealing performance after the connection between the first housing part 51 and the second housing part 52, a sealing member can also be provided between the first housing part 51 and the second housing part 52, such as sealant, sealing ring, etc.

[0069] Assume that the first housing part 51 covers the top of the second housing part 52. The first housing part 51 can also be called the upper cover, and the second housing part 52 can also be called the lower housing.

[0070] In the battery 2, there are multiple battery cells 6. The multiple battery cells 6 can be connected in series, in parallel, or in a series-parallel combination. A series-parallel combination means that there are both series and parallel connections among the multiple battery cells 6. The multiple battery cells 6 can be directly connected in series, in parallel, or in a series-parallel combination together, and then the whole formed by the multiple battery cells 6 is accommodated in the housing 5. Of course, it can also be that multiple battery cells 6 are first connected in series, in parallel, or in a series-parallel combination to form a battery module (not shown in the figure), and then multiple battery modules are connected in series, in parallel, or in a series-parallel combination to form a whole and are accommodated in the housing 5.

[0071] Please refer to Figure 3 , Figure 3 which is an explosion schematic diagram of the battery cell 6 provided by some embodiments of this application. As Figure 3As shown, the battery cell 6 may include an electrode assembly 61, a housing 62, an end cap 63, and an electrolyte (not shown in the figure). The electrode assembly 61 may include a positive electrode tab, a negative electrode tab, and a separator (not marked in the figure). The battery cell 6 mainly operates by the movement of metal ions between the positive electrode tab and the negative electrode tab. The positive electrode tab includes a positive current collector and a positive active material layer, and the positive active material layer is coated on the surface of the positive current collector; the positive current collector includes a positive current collecting portion coated with the positive active material layer. Taking a lithium-ion battery as an example, the material of the positive current collector may be aluminum, and the positive active material layer includes a positive active material, and the positive active material may be lithium cobaltate, lithium iron phosphate, ternary lithium, or lithium manganate, etc. The negative electrode tab includes a negative current collector and a negative active material layer, and the negative active material layer is coated on the surface of the negative current collector; the negative current collector includes a negative current collecting portion coated with the negative active material layer. The material of the negative current collector may be copper, and the negative active material layer includes a negative active material, and the negative active material may be carbon or silicon, etc. The material of the separator may be PP (polypropylene) or PE (polyethylene), etc. In addition, the electrode assembly 61 may be a wound structure or a stacked structure, and the embodiments of the present application are not limited thereto. The housing 62 may have an opening at one end or openings at both ends, and the end cap 63 covers the opening of the housing 62 to jointly form a receiving space for receiving the electrode assembly 61 and the electrolyte with the housing 62. Optionally, the housing 62 and the end cap 63 may be made of the same material. For example, the housing 62 and the end cap 63 may both be made of aluminum, so that it is convenient to weld the housing 62 and the end cap 63. Alternatively, the housing 62 and the end cap 63 may also be made of different materials. For example, the housing 62 and the end cap 63 may be made of different metals respectively, and other connection methods such as riveting may be used to connect the housing 62 and the end cap 63.

[0072] Please refer to Figures 4 to 5 , Figure 4 which is a schematic structural diagram of the electrode assembly 61 provided by some embodiments of the present application, Figure 5 and which is a schematic structural diagram of the unfolded first current collector 611 and second current collector 612 provided by some embodiments of the present application.

[0073] As Figure 4 and Figure 5 shown, some embodiments of the present application provide an electrode assembly 61. The electrode assembly 61 includes a first current collector 611. The first current collector 611 includes a first coating area 611a and a second coating area 611b. The first coating area 611a is coated with an active material material, and the second coating area 611b is coated with a lithium supplement material. Along the extension direction X of the first current collector 611, a first interval 611c is provided between the first coating area 611a and the second coating area 611b.

[0074] As described above, the active material includes a positive active material and a negative active material. The positive active material is coated on the positive current collector to form a positive active material layer, and the negative active material is coated on the negative current collector to form a negative active material layer. The positive active material may include lithium cobaltate, lithium iron phosphate, ternary lithium, or lithium manganate, etc., and the negative active material may include carbon or silicon, etc.

[0075] The lithium supplement material can be used to supplement the content of lithium ions in the electrolyte for the lithium intercalation reaction of the negative active material layer coated on the negative current collector. The lithium supplement material may include materials such as lithium-containing oxides and lithium foils, which can be compounded onto the positive current collector or compounded onto the negative current collector to form a lithium source and continuously supplement lithium ions to the electrolyte.

[0076] The first current collector 611 can be a positive current collector or a negative current collector. When the first current collector 611 is a positive current collector, the first coating area 611a can be used to coat the positive active material, and the second coating area 611b is used to coat the lithium supplement material. The coating length and coating thickness of the first coating area 611a and the second coating area 611b will affect the coating amount of the active material and the coating amount of the lithium supplement material. The coating amounts of the active material and the lithium supplement material can be set according to the model of the battery cell 6. The lithium supplement material can be coated on one surface of the first current collector 611 along the thickness direction or can be provided on both surfaces of the first current collector 611 along the thickness direction. The present application does not limit this.

[0077] When the lithium supplement material comes into contact with the negative active material, since it is difficult to ensure the uniform coating thickness at the contact area between the lithium supplement material and the negative active material, over-lithium supplementation is likely to occur in the area where the coating thickness of the lithium supplement material is relatively large, resulting in lithium deposition on the electrode sheet; when the lithium supplement material comes into contact with the positive active material, it is likely to cause the positive active material layer to be too thick, and the lithium ions inside are not easily released, resulting in poor lithium supplementation effect. As Figure 4 or Figure 5 shown, a first gap 611c is provided between the first coating area 611a and the second coating area 611b. In this way, the first gap 611c can separate the active material coated on the first coating area 611a from the lithium supplement material coated on the second coating area 611b, which can not only reduce the probability of lithium deposition phenomenon but also improve the release efficiency of lithium ions, thereby improving the lithium supplementation effect.

[0078] In some embodiments of the present application, please continue to refer to Figure 4 and Figure 5, the electrode assembly 61 further includes a second current collector 612. The first current collector 611 and the second current collector 612 are wound to form the electrode assembly 61. Along the winding direction of the electrode assembly 61 (parallel to the extension direction X of the first current collector 611), the first current collector 611 includes an extended portion 611d that extends beyond the second current collector 612, and the second coating area 611b is located in the extended portion 611d.

[0079] The second current collector 612 has the opposite polarity to the first current collector and can be a positive current collector or a negative current collector. The lithium supplement material is arranged in the extended portion 611d where the first current collector 611 extends beyond the second current collector 612 along the winding direction. In this way, the first current collector 611 can be successively coated with the lithium supplement material and the active material, which is convenient for processing and only requires switching the material once. Moreover, only one first interval 611c needs to be set between the first coating area 611a and the second coating area 611b, and more surface area of the first current collector 611 can be used to coat the lithium supplement material or the active material, so as to improve the utilization rate of the surface area of the first current collector 611.

[0080] Please refer to Figure 5 and Figure 6 , where Figure 6 is a schematic structural diagram of the unfolded first current collector 611 and second current collector 612 provided in some other embodiments of the present application.

[0081] In some embodiments of the present application, as Figure 5 and Figure 6 shown, the first interval 611c is at least partially located in the extended portion 611d.

[0082] In the electrode assembly 61, the amounts of the positive electrode active material and the negative electrode active material usually need to be matched with each other to ensure the capacity of the battery cell. To provide sufficient lithium insertion sites for the positive electrode active material, it is usually necessary to form a structure in which the negative electrode active material layer extends beyond the positive electrode active material layer, that is, the length of the negative electrode active material coated on the negative current collector needs to cover and exceed the length of the positive electrode active material coated on the positive current collector.

[0083] As Figure 5 shown, when the first current collector 611 is a negative current collector, to form the above structure, the first interval 611c can be completely located in the extended portion 611d, and at least part of the first coating area 611a is also located in the extended portion 611d to cover and exceed the coating area of the positive electrode active material coated on the second current collector 612.

[0084] As Figure 6As shown, when the first current collector 611 is the positive current collector, in order to form the above structure, part of the first interval 611c can be arranged in the extension part 611d, and part of the first interval 611c is located in the part outside the extension part 611d. When the first current collector 611 and the second current collector 612 are wound, this part of the first interval 611c can be opposite to the negative active material layer on the second current collector 612, so that the negative active material layer on the second current collector 612 covers and extends beyond the coating area where the positive active material is coated on the first current collector 612.

[0085] Please refer to Figure 7 , Figure 7 which is a schematic structural diagram of the electrode assembly 61 provided in some other embodiments of the present application.

[0086] In some embodiments of the present application, as Figure 7 shown, the first current collector 611 includes at least two first coating areas 611a, and a second coating area 611b is arranged between two adjacent first coating areas 611a.

[0087] Two first coating areas 611a can be arranged at intervals on the first current collector 611. The first coating area 611a is used for coating the active material, which can be the positive active material or the negative active material.

[0088] When the first coating area 611a is coated with the negative active material, the second coating area 611b left in the middle of the two first coating areas 611a is used for coating the lithium supplement material. In this way, during the cyclic use of the battery cell 6, the lithium supplement material can supplement lithium ions to the electrolyte, and the lithium ions can diffuse to the two first coating areas 611a on both sides and finally be embedded in the negative active material layer on the first coating area 611a, which can shorten the movement path of the lithium ions and improve the efficiency of lithium intercalation. When the first coating area 611a is coated with the positive active material, the second coating area 611b left in the middle of the two first coating areas 611a is used for coating the lithium supplement material, which can also shorten the distance for the lithium supplement material to reach the lithium intercalation position and improve the efficiency of lithium intercalation.

[0089] In other embodiments of the present application, the first current collector 611 can also include a plurality of first coating areas 611a, and a second coating area 611b can be arranged between every two adjacent first coating areas 611a. Optionally, the first current collector 611 can also include a plurality of first intervals 611c, and a first interval 611c is arranged between the adjacent first coating area 611a and the second coating area 611b to prevent the lithium supplement material from contacting the active material. The present application does not limit this.

[0090] In some embodiments of the present application, please continue to refer to Figure 7, the electrode assembly 61 further includes at least two second current collectors 612. The first current collector 611 and the second current collectors 612 are wound to form the electrode assembly 61. A second interval 613 is provided between two adjacent second current collectors 612, and the second coating area 611b is disposed opposite to the second interval 613.

[0091] When the lithium supplement material and the cathode active material are located on two opposite surfaces of the first current collector 611 and the second current collector 612 respectively, under the action of the charge and discharge voltage of the battery cell 6, lithium ions in the cathode active material easily migrate to the surface layer of the lithium supplement material and precipitate, causing lithium precipitation on the surface of the lithium supplement material. Moreover, the precipitated lithium will further prevent lithium ions in the lithium supplement material from escaping into the electrolyte, thereby affecting the lithium supplement effect. When the first current collector 611 is a negative current collector, the first coating area 611a is used to coat the negative active material, the second coating area 611b is used to coat the lithium supplement material, and multiple second current collectors 612 are all used to coat the cathode active material, so that the second coating area 611b is disposed opposite to the second interval 613 between the adjacent second current collectors 612. In this way, it is possible to prevent the lithium supplement material on the second coating area 611b from facing the cathode active material on the second current collector 612, resulting in lithium precipitation on the surface of the lithium supplement material. In this way, while ensuring the lithium supplement effect, the lithium precipitation probability of the battery cell 6 can be reduced to improve its safety performance.

[0092] When the lithium supplement material faces the positive current collector, under the action of the charge and discharge voltage of the battery cell 6, lithium ions in the lithium supplement material may also precipitate on the surface of the positive current collector, affecting the safety performance of the battery cell 6. When the first current collector 611 is a positive current collector, the first coating area 611a on the first current collector 611 is used to coat the cathode active material, and the second coating area 611b is used to coat the lithium supplement material. In this way, it is possible to prevent the lithium supplement material coated on the second coating area 611b from facing the blank and uncoated second current collector 612, so as to avoid the lithium released from the lithium supplement material from finally precipitating on the surface of the second current collector 612 and affecting the safe use of the battery cell 6.

[0093] Please refer to Figure 8 , Figure 8 which is a schematic structural diagram of the electrode assembly 61 provided by some other embodiments of the present application.

[0094] In some embodiments of the present application, as Figure 8 shown, the electrode assembly 61 further includes a second current collector 612. The first current collector 611 and the second current collector 612 are wound to form the electrode assembly 61. A third coating area 612a and a fourth coating area 612b are provided on the second current collector 612. A third interval 612c is provided between the third coating area 612a and the fourth coating area 612b, and the second coating area 611b is disposed opposite to the third interval 612c.

[0095] A third coating area 612a and a fourth coating area 612b are provided on the second current collector 612, and a third interval 612c is provided between the third coating area 612a and the fourth coating area 612b, that is, a blank current collector vacant area is provided on the second current collector 612. When the first current collector 611 is a negative current collector, the second coating area 611b coated with the lithium supplement material is made to face the third interval 612c. In this way, it is possible to prevent the second coating area 611b coated with the lithium supplement material from facing the third coating area 612a or the fourth coating area 612b on the second current collector 612, so as to prevent lithium released from the positive active material on the third coating area 612a or the fourth coating area 612b from generating lithium deposition on the surface of the lithium supplement material, affecting the safety performance of the battery cell 6 and the effect of lithium supplementation.

[0096] Please refer to Figures 4 to 8 , in some embodiments of the present application, the size of the first interval 611c along the extension direction X of the first current collector 611 is greater than or equal to 1 mm.

[0097] The first interval 611c is used to separate the lithium supplement material and the active material to prevent phenomena such as lithium deposition and regional over-lithium supplementation caused by the contact between the lithium supplement material and the active material. Making the size of the first interval 611c along the extension direction X of the first current collector 611 greater than or equal to 1 mm enables the lithium supplement material and the active material to maintain a certain distance and not overlap.

[0098] Please refer to Figure 9 , Figure 9 is a schematic structural diagram of the first current collector 611 provided in some embodiments of the present application.

[0099] As Figure 9 shown, the first current collector 611 may include a first surface A1 and a second surface A2 opposite to each other in the thickness direction Y thereof, and the second coating area 611b is located on the first surface A1 and / or the second surface A2.

[0100] Optionally, both surfaces A1 and A1 of the first current collector 611 may be coated with the lithium supplement material and the active material, or one of the two surfaces A1 and A1 of the first current collector 611 may be used to coat the active material, and the other may be used to coat the lithium supplement material and the active material. When one surface of the first current collector 611, such as A1, is used to coat the lithium supplement material and the active material, a third interval 612c may be correspondingly provided on the surface of the second current collector 612 opposite to A1, or a second interval 613 may be provided, without the need for special setting of the two relative positions, which is convenient for processing.

[0101] As Figure 9As shown, when both surfaces A1 and A2 on the second current collector 612 are coated with a lithium supplement material and an active material, in this way, when the required amount of the lithium supplement material is fixed, the length of the second coating area 611b along the extension direction X of the first current collector 611 can be shortened, and the lithium supplement material can be coated on both sides simultaneously to shorten the coating time. In addition, when the lithium supplement material is coated on both surfaces A1 and A2, different coating lengths can be set to respectively meet different lithium supplement requirements.

[0102] Although the present application has been described with reference to the preferred embodiments, various modifications can be made to it and components thereof can be replaced with equivalents without departing from the scope of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments provided in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. An electrode assembly, characterized in that, Comprising: A first current collector, the first current collector including a first coating area and a second coating area, the first coating area being coated with an active material, the second coating area being coated with a lithium supplement material, and a first interval being provided between the first coating area and the second coating area along the extending direction of the first current collector; The electrode assembly further includes a second current collector, and the first current collector and the second current collector are wound to form the electrode assembly; The second coating area is located at the starting end of the first current collector; or, there are at least two first coating areas, and the second coating area is located between two adjacent first coating areas.

2. The electrode assembly according to claim 1, wherein, When the second coating area is located at the starting end of the first current collector, along the winding direction of the electrode assembly, the first current collector includes an extending portion exceeding the second current collector, and the second coating area is located in the extending portion.

3. The electrode assembly according to claim 2, wherein At least part of the first interval is located in the extending portion.

4. The electrode assembly according to claim 1, wherein When the second coating area is located between two adjacent first coating areas, there are at least two second current collectors, a second interval is provided between two adjacent second current collectors, and the second coating area is disposed opposite to the second interval.

5. The electrode assembly according to claim 1, characterized in that, When the second coating area is located between two adjacent first coating areas, a third coating area and a fourth coating area are provided on the second current collector, a third interval is provided between the third coating area and the fourth coating area, and the second coating area is disposed opposite to the third interval.

6. The electrode assembly according to any one of claims 1-5, characterized in that, The first interval is greater than or equal to 1 mm.

7. The electrode assembly according to any one of claims 1-5, characterized in that The first current collector includes a first surface and a second surface opposite to each other in the thickness direction, and the second coating area is located on the first surface and / or the second surface.

8. A battery cell, characterized in that, Comprising the electrode assembly according to any one of claims 1-7.

9. A battery, characterized in that, Comprising the battery cell according to claim 8.

10. An electrical device, characterized in that, Comprising the battery according to claim 9, wherein the battery is used to provide electrical energy.

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