Battery monomer, battery and energy storage device

Abstract

The utility model relates to the field of batteries, and discloses a single battery, a battery and an energy storage device, the single battery comprises an electrode assembly, the electrode assembly comprises a first pole piece, the first pole piece comprises a first current collector, the first current collector comprises a first main body part and a first tab, and the first tab protrudes out of the first main body part; two surfaces of the first main body part are respectively coated with a first active material layer; the first pole piece further comprises a first insulating layer and a second insulating layer, the first insulating layer and the second insulating layer are at least partially coated on the two opposite sides of the first pole lug respectively, the first insulating layer and the first active substance layer are arranged at intervals on one surface of the first pole piece in the first direction, and the second insulating layer and the second active substance layer are arranged at intervals on the other surface of the first pole piece in the second direction. The second insulating layer is at least partially coated on the first active material layer. According to the technical scheme of the embodiment of the invention, the problems of electrode lug wrinkling and insufficient electrode lug flexibility caused by rolling can be balanced at the same time, the risk that the insulating layer and the active material fall off is reduced, and the reliability of the battery monomer is improved.

Description

Technical Field

[0001] The present application relates to the field of batteries, and in particular to a battery cell, a battery, and an energy storage device. Background Art

[0002] New energy batteries are increasingly being used in everyday life and industry. For example, battery-powered new energy vehicles are already widely used. Furthermore, batteries are increasingly being used in energy storage and other fields. In new energy vehicles, batteries can provide full or partial power. In energy storage, batteries can be installed in energy storage boxes or directly at the user's side.

[0003] For soft-pack batteries, the battery tabs are easily torn and cracked by external forces, and the ceramic coating and active materials may fall off, affecting the reliability of the battery cells. Utility Model Content

[0004] In view of the above problems, the present application provides a battery cell, a battery, an energy storage device and an electrical device, which can improve the reliability of the battery cell.

[0005] In the first aspect, the present application provides a battery cell, comprising: an electrode assembly, the electrode assembly comprising a first pole piece, the first pole piece comprising a first current collector, the first current collector comprising a first main body and a first pole tab, the first pole tab protruding from the first main body along a first direction, and the two surfaces of the first main body are respectively coated with a first active material layer; the first pole piece also comprises a first insulating layer and a second insulating layer, the first insulating layer and the second insulating layer are respectively at least partially coated on opposite sides of the first pole tab, on one surface of the first pole piece, the first insulating layer and the first active material layer are spaced apart in the first direction, and on the other surface of the first pole piece, the second insulating layer is at least partially coated on the first active material layer.

[0006] In the technical solution of the embodiment of the present application, a first insulating layer and a second insulating layer are coated on both sides of the first electrode, and a certain buffer zone is formed by arranging the first insulating layer and the first active material layer at intervals. The second insulating layer covers the first active material layer, which can simultaneously balance the problem of wrinkling of the electrode tab caused by rolling and the problem of insufficient flexibility of the electrode tab, reduce the risk of falling off of the insulating layer and the active material, and improve the reliability of the battery cell.

[0007] In some embodiments, in the first direction, a minimum distance between the first insulating layer and an edge of the first active material layer is D1, and 10 μm≤D1≤80 μm.

[0008] In some embodiments, a minimum dimension of a portion of the second insulating layer coating the first active material layer in the first direction is D2, where 0<D2≤600 μm.

[0009] In some embodiments, the first electrode piece further includes a third insulating layer, the third insulating layer is coated on an end of the first main body opposite to the first electrode tab, and the third insulating layer is at least partially coated on the first active material layer.

[0010] In some embodiments, a minimum dimension of a portion of the third insulating layer coating the first active material layer in the first direction is D3, where 0<D3≤600 μm.

[0011] In some embodiments, opposite sides of the first main body are respectively coated with the third insulating layer.

[0012] In some embodiments, the first active material layer includes a first flat coating area and a first thinned area, the first thinned area is close to the first electrode tab relative to the first flat coating area, the first insulating layer is spaced apart from the first thinned area, and the second insulating layer coats at least a portion of the first thinned area.

[0013] In some embodiments, the electrode assembly further includes a second electrode sheet, the second electrode sheet is a negative electrode sheet, the first electrode sheet is a positive electrode sheet, the second electrode sheet includes a second current collector, the second current collector includes a second main body and a second electrode tab, the second electrode tab protrudes from the second main body along a first direction, and the surface of the second main body (211) is coated with a second active material layer, wherein, in the first direction, the length of the second active material layer is greater than the length of the first active material layer.

[0014] In some embodiments, in the first direction, the length of the first active material layer is L1, the length of the second active material layer is L2, and 5 mm ≤ L2 - L1 ≤ 8 mm.

[0015] In some embodiments, the maximum thickness of the first insulating layer is H1, 5 μm≤H1≤30 μm.

[0016] In some embodiments, the maximum thickness of the second insulating layer is H2, 5 μm≤H2≤30 μm.

[0017] In a second aspect, the present application provides a battery comprising the battery cell in the above embodiment.

[0018] In a third aspect, the present application provides an energy storage device, which includes the battery in the above embodiment.

[0019] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0021] Figure 1 A schematic structural diagram of an energy storage device provided in some embodiments of the present application;

[0022] Figure 2 A schematic diagram of a battery provided in some embodiments of the present application;

[0023] Figure 3 A schematic diagram of a battery cell provided in some embodiments of the present application;

[0024] Figure 4 A schematic diagram of one side of a first pole piece provided in some embodiments of the present application;

[0025] Figure 5 A schematic diagram of the other side of the first pole piece provided in some embodiments of the present application;

[0026] Figure 6 A schematic diagram of one side of a first pole piece provided in some other embodiments of the present application;

[0027] Figure 7 A schematic diagram of the other side of the first pole piece provided in some other embodiments of the present application;

[0028] Figure 8 A cross-sectional view of a first pole piece provided in some embodiments of the present application;

[0029] Figure 9 for Figure 8 The middle circle shows an enlarged view of point A;

[0030] Figure 10 A partial cross-sectional view of a battery cell provided in some embodiments of the present application.

[0031] Reference numerals:

[0032] Battery 1000, energy storage device 3000,

[0033] Battery cell 100, control unit 400, box 500,

[0034] Electrode assembly 110,

[0035] First electrode 10, first current collector 11, first main body 111, first electrode tab 112, first active material layer 12, first flat coating area 121, first skived area 122, first insulating layer 13, second insulating layer 14, third insulating layer 15,

[0036] The second electrode sheet 20, the second current collector 21, the second main body 211, the second electrode tab 212, the second active material layer 22,

[0037] Isolation member 30. DETAILED DESCRIPTION

[0038] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0039] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application 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 and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0040] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments.

[0041] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0042] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. Additionally, in this application, the character " / " generally indicates that the related objects before and after are in an "or" relationship.

[0043] In the embodiments of this 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 this 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 this application.

[0044] The term "a plurality of" as used in this application refers to two or more (including two).

[0045] In this application, a battery refers to a single physical module that includes one or more battery cells to provide a higher voltage and capacity. For example, the batteries mentioned in this application can include battery modules or battery packs, etc. Some batteries can include a housing for encapsulating one or more battery cells or multiple battery modules. The housing can prevent liquids or other foreign objects from affecting the charging or discharging of the battery cells. Of course, there are also some batteries that do not include the above-mentioned housing and are directly installed in the battery installation compartment of the electrical device.

[0046] In this application, the battery cell can include a lithium-ion secondary battery, a lithium-ion primary battery, a lithium-sulfur battery, a sodium-lithium-ion battery, a sodium-ion battery, a magnesium-ion battery, etc., and the embodiments of this application are not limited thereto. The battery cell can be in a cylindrical shape, a flat shape, a cuboid shape, or other shapes, and the embodiments of this application are also not limited thereto.

[0047] For example, a battery cell can include a package body, an electrode assembly, and an electrolyte. The package body is used to accommodate the electrode assembly and the electrolyte. The electrode assembly is composed of a positive electrode tab, a negative electrode tab, and a separator. The battery cell 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 electrode current collector and a positive electrode active material layer. The positive electrode active material layer is coated on the surface of the positive electrode current collector. The positive electrode current collector without the coated positive electrode active material layer protrudes from the positive electrode current collector with the coated positive electrode active material layer. The positive electrode current collector without the coated positive electrode active material layer serves as the positive electrode ear. Taking a lithium-ion battery as an example, the material of the positive electrode current collector can be aluminum, and the positive electrode active material can be lithium cobaltate, lithium iron phosphate, ternary lithium, or lithium manganate, etc.

[0048] The negative electrode sheet consists of a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative current collector. The negative current collector uncoated with the negative active material layer protrudes from the negative current collector coated with the negative active material layer. The negative current collector uncoated with the negative active material layer serves as the negative electrode tab. The negative current collector can be made of copper, and the negative active material can be carbon, silicon, or other materials. To ensure that high currents can pass without melting, multiple positive electrode tabs are stacked together, and multiple negative electrode tabs are stacked together.

[0049] The material of the separator may be PP (polypropylene) or PE (polyethylene), etc. In addition, the electrode assembly may be a wound structure or a laminated structure, but the embodiments of the present application are not limited thereto.

[0050] In order to improve the risk of short circuit of battery cells caused by burrs on the positive electrode sheet, an insulating layer is usually coated on both sides of the tab side of the positive electrode sheet to reduce the occurrence of burrs. The insulating layer is usually coated on the positive electrode active material layer and extends to the root of the tab. However, after the insulating layer is coated, the hardness of the root of the positive electrode tab increases.

[0051] For soft-pack batteries, the battery tabs are directly connected to the conductive components. When the conductive components are shaken by external forces during battery assembly or actual application, the tabs are not flexible enough to adapt to small shakes, causing the tabs to be torn and cracked by external forces. When the tabs are pulled and shaken by external forces, there is also a risk of the insulating layer and active material falling off, thereby increasing safety risks and affecting the reliability of the battery cells.

[0052] To this end, the present application proposes a battery cell, comprising: an electrode assembly, the electrode assembly comprising a first electrode sheet, the first electrode sheet comprising a first current collector, the first current collector comprising a first main body and a first electrode tab, the first electrode tab protruding from the first main body along a first direction, and the two surfaces of the first main body being respectively coated with a first active material layer; the first electrode sheet also comprises a first insulating layer and a second insulating layer, the first insulating layer and the second insulating layer being respectively at least partially coated on opposite sides of the first electrode tab, at least part of the first insulating layer is spaced apart from the first active material layer in the first direction on one surface of the first electrode sheet, and the second insulating layer is at least partially coated on the first active material layer on the other surface of the first electrode sheet.

[0053] According to the battery cell of the embodiment of the present application, a first insulating layer and a second insulating layer are coated on both sides of the first electrode piece, and a certain buffer zone is formed by arranging the first insulating layer and the first active material layer at intervals. The second insulating layer covers the first active material layer. This can simultaneously balance the problem of wrinkling of the electrode tab caused by rolling and the problem of insufficient flexibility of the electrode tab, reduce the risk of falling off of the insulating layer and the active material, and improve the reliability of the battery cell.

[0054] The battery provided by the embodiment of the present application includes the above battery cell. The battery can be used in, but is not limited to, power storage power systems, vehicles, ships, aircraft and other power-consuming devices.

[0055] The embodiment of the present application provides an energy storage device for storing and supplying electrical energy using the above battery. The energy storage device can include, but is not limited to, energy storage containers, energy storage cabinets, etc.

[0056] In the following embodiments, for the convenience of description, the energy storage device 3000 of some embodiments of the present application is taken as an example for illustration. The following is described with reference to the drawings.

[0057] Figure 1 It is a schematic structural diagram of the energy storage device 3000 provided by some embodiments of the present application. The energy storage device 3000 can be an energy storage container, an energy storage cabinet, etc. As Figure 1 shown, the energy storage device 3000 can include a battery 1000 and a control unit 400. The control unit 400 is used to control the charge and discharge of the battery 1000 to ensure the normal operation of the battery 1000. For example, it is used to monitor parameters such as ambient temperature and humidity.

[0058] Figure 2 It is a schematic diagram of the battery provided by some embodiments of the present application. As Figure 2 shown, the battery 1000 includes a box body 500. The box body can be divided into an upper box body (not shown) and a lower box body. The upper box body and the lower box body are opposed to each other to form a receiving space for the battery cell 100 therebetween.

[0059] Next, refer to Figures 3 to 10 for a detailed description of some embodiments of the present application. Figure 3 It is a schematic diagram of the battery cell provided by some embodiments of the present application; Figures 4 - 9 It is a schematic diagram of the first electrode plate provided by some embodiments of the present application; Figure 10 It is a partial cross-sectional view of the battery cell provided by some embodiments of the present application.

[0060] Some battery cells 100 of the embodiments of the present application include: an electrode assembly 110, the electrode assembly 110 includes a first pole piece 10, the first pole piece 10 includes a first current collector 11, the first current collector 11 includes a first main body 111 and a first pole tab 112, the first pole tab 112 protrudes from the first main body 111 along the first direction F1, and the two surfaces of the first main body 111 are respectively coated with a first active material layer 12; the first pole piece 10 also includes a first insulating layer 13 and a second insulating layer 14, the first insulating layer 13 and the second insulating layer 14 are respectively at least partially coated on opposite sides of the first pole tab 112, on one surface of the first pole piece 10, the first insulating layer 13 and the first active material layer 12 are arranged alternately in the first direction F1, and on the other surface of the first pole piece 10, the second insulating layer 14 is at least partially coated on the first active material layer 12.

[0061] The battery cell 100 is a battery cell 100 that uses a flexible packaging film as its packaging. Compared to battery cells 100 that use a rigid metal packaging structure, the battery cell 100 is lightweight and can be easily diversified in its outer shape.

[0062] The battery cell 100 includes an electrode assembly 110 and a packaging body 120 . The packaging body is a shell formed by bending and packaging the soft packaging film of the battery cell 100 . The specific form of the packaging film forming the packaging body is not limited, for example, an aluminum-plastic film.

[0063] The packaging body 120 has a receiving cavity therein for receiving the electrode assembly 110 and the electrolyte. The charging and discharging functions of the battery cell 100 are realized through the electrochemical reaction between the electrode assembly 110 and the electrolyte.

[0064] The electrode assembly 110 includes pole pieces and separators 30. The pole pieces include a first pole piece 10 and a second pole piece 20. The first pole piece 10 can be a positive pole piece, and the second pole piece 20 can be a negative pole piece. During the charge and discharge process of the battery cell 100, active ions (such as lithium ions) are embedded and released back and forth between the positive electrode and the negative electrode. The separator 30 is arranged between the first pole piece 10 and the second pole piece 20, which can prevent the positive and negative electrodes from short-circuiting and allow active ions to pass through. The first pole piece 10, the second pole piece 20 and the separator can be stacked and wound to form a stacked winding body. The electrode assembly 110 is not limited to a wound type, and can also be a laminated type or other structural form.

[0065] The first current collector 11 can be an aluminum foil, and the first current collector 11 includes a first main body 111 and a first electrode tab 112. The first electrode tab 112 protrudes from the first main body 111 along the first direction F1. The two side surfaces of the first main body 111 are respectively coated with a first active material layer 12. The first active material layer 12 can be a ternary material, lithium manganese oxide or lithium iron phosphate.

[0066] In order to improve the risk of short circuit of the battery cell caused by burrs on the first pole piece, an insulating layer is also coated on the first pole piece 10. Specifically, the insulating layer includes a first insulating layer 13 and a second insulating layer 14. The first insulating layer 13 is coated on the first surface of the first pole piece 10, and the first insulating layer 13 is at least partially coated on the first pole ear 112. In the first direction F1, the first insulating layer 13 and the first active material layer 12 are arranged at intervals; the second insulating layer 14 is coated on the second surface of the first pole piece 10, and the second insulating layer 14 is at least partially coated on the first pole ear 112. In the first direction F1, the second insulating layer 14 is at least partially coated on the first active material layer 12.

[0067] It should be noted that some first active material layers 12 include a first flat coating area 121 and a first thinning area 122 arranged along the first direction F1, and the first insulating layer 13 is spaced apart from the first thinning area 122; some first active material layers 12 only include the first flat coating area 121, and the first insulating layer 13 is spaced apart from the first flat coating area 121.

[0068] That is, an insulating layer is coated on both sides of the first electrode piece 10, and the coating method of the insulating layer on both sides is different. On the first side, a certain distance is reserved between the insulating layer and the edge of the first active material layer 12 to form a buffer zone. On the second side, the insulating layer covers a part of the first active material layer 12 and extends to the root of the first electrode ear 112.

[0069] If the insulating layers on both sides cover the first active material layer 12, the first pole ear 112 will be harder and less flexible. When subjected to external force, the insulating layer and the active material will easily fall off. If the insulating layers on both sides are spaced a certain distance from the edge of the first active material layer 12, then during the subsequent pole piece rolling process, due to the different ductility between the active material area, the insulating area and the intermediate buffer area, wrinkles will appear at the pole ear connection, affecting the manufacturability and reliability of the electrode assembly 110.

[0070] Therefore, by arranging the first insulating layer 13 and the first active material layer 12 at intervals to form a certain buffer zone, and the second insulating layer 14 covers the first active material layer 12, the problem of tab wrinkling and the problem of insufficient tab flexibility caused by rolling can be balanced at the same time, thereby improving and reducing the safety risk of the battery cell 100.

[0071] According to the battery cell 100 of the embodiment of the present application, by coating the first insulating layer 13 and the second insulating layer 14 on both sides of the first electrode tab 10, and arranging the first insulating layer 13 at an interval from the first active material layer 12 to form a certain buffer zone, and the second insulating layer 14 covering the first active material layer 12, the problems of ear wrinkling and insufficient ear flexibility caused by rolling can be balanced simultaneously, the risk of the insulating layer and the active material material falling off can be reduced, and the reliability of the battery cell 100 can be improved.

[0072] As Figure 4 and Figure 6 shown, in some embodiments, in the first direction F1, the minimum distance between the edge of the first insulating layer 13 and the first active material layer 12 is D1, and 10μm ≤ D1 ≤ 80μm.

[0073] If the distance between the edge of the first insulating layer 13 and the first active material layer 12 is too large, the buffer zone between the first insulating layer 13 and the first active material layer 12 will be too wide, and it will be difficult to control the extension problem between different regions during the rolling of the electrode tab; if the distance between the edge of the first insulating layer 13 and the first active material layer 12 is too small, there will not be enough buffer zone for the ear, and it will be difficult to meet the requirement of ear flexibility.

[0074] Therefore, D1 is limited to be between 10μm and 80μm, and D1 can be any value among 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm or the range value between any two of them. By limiting D1 within the above range, the problems of ear wrinkling and insufficient ear flexibility caused by rolling can be balanced simultaneously, the risk of the insulating layer and the active material material falling off can be reduced, and the reliability of the battery cell 100 can be improved.

[0075] As Figure 5 and Figure 7 shown, in some embodiments, the minimum size of the part of the second insulating layer 14 coating the first active material layer 12 in the first direction F1 is D2, and 0 < D2 ≤ 600μm.

[0076] As Figure 5 and Figure 7 shown, the second insulating layer 14 and the first active material layer 12 have an overlapping part, and the size of this overlapping part in the first direction F1 is D2.

[0077] Among them, since both the insulating layer and the active material layer are slurries during coating, it is easy to form a "virtual edge", resulting in difficulty in gripping the edge in subsequent processes. In order to facilitate subsequent manufacturing and edge detection, D2 needs to be greater than 0. In addition, if D2 is too large, the second insulating layer 14 covers too much area of the first active material layer 12, which will affect the efficiency of the active material insertion and extraction, thereby affecting the capacity of the battery cell 100.

[0078] To this end, D2 can be limited to between 0 and 600 μm. D2 can be any value among 1 μm, 50 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, 550 μm, and 600 μm, or a range therebetween. By limiting D2 to the above range, subsequent manufacturing and edge inspection can be facilitated while minimizing the impact on the capacity of the battery cell 100.

[0079] like Figure 6 and Figure 7 As shown, in some embodiments, the first electrode piece 10 further includes a third insulating layer 15 , which is coated on an end of the first main body portion 111 opposite to the first electrode tab 112 , and the third insulating layer 15 is at least partially coated on the first active material layer 12 .

[0080] like Figure 6 and Figure 7 As shown, the third insulating layer 15 covers the other end of the first main body 111 in the first direction F1, and the third insulating layer 15 covers the edge of the first main body 111, thereby reducing the risk of short circuit caused by cutting burrs of the first main body 111, and the third insulating layer 15 has an overlapping portion with the first active material layer 12, thereby avoiding the generation of "virtual edges", which facilitates subsequent manufacturing and edge detection.

[0081] In some embodiments, the portion of the third insulating layer 15 coating the first active material layer 12 has a minimum dimension D3 in the first direction F1 , where 0<D3≤600 μm.

[0082] like Figure 6 As shown, the third insulating layer 15 and the first active material layer 12 have an overlapping portion, and the dimension of the overlapping portion in the first direction F1 is D3.

[0083] Among them, since the insulating layer and the active material layer are both slurries during coating, "virtual edges" are easily formed, which makes it difficult to grasp the edges in subsequent processes. In order to facilitate subsequent manufacturing and edge detection, D3 needs to be greater than 0. In addition, if D3 is too large, the third insulating layer 15 covers too much area of the first active material layer 12, which will affect the efficiency of active material deintercalation, thereby affecting the capacity of the battery cell 100.

[0084] To this end, D3 can be limited to between 0 and 600 μm, and D2 can be any value among 1 μm, 50 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, 550 μm, and 600 μm, or a range therebetween. Limiting D3 to this range facilitates subsequent manufacturing and edge inspection while minimizing the impact on the capacity of the battery cell 100.

[0085] like Figures 6 - 8 As shown, in some embodiments, two opposite sides of the first main body portion 111 are respectively coated with a third insulating layer 15 .

[0086] like Figure 8 As shown, the third insulating layer 15 is coated on both sides of the first main body 111 in the second direction F2, wherein the sizes of the overlapping parts of the third insulating layer 15 and the first active material layer 12 on both sides of the first main body 111 can be the same or different.

[0087] By disposing the third insulating layer 15 on both sides of the first main body portion 111 , the risk of short circuit caused by cutting burrs of the first main body portion 111 can be further reduced, thereby improving the reliability of the battery cell 100 .

[0088] like Figure 8 and Figure 9 As shown, in some embodiments, the first active material layer 12 includes a first flat coating area 121 and a first thinned area 122, the first thinned area 122 is close to the first pole ear 112 relative to the first flat coating area 121, the first insulating layer 13 is spaced apart from the first thinned area 122, and the second insulating layer 14 coats at least a portion of the first thinned area 122.

[0089] like Figure 9 As shown, on the first main body 111, the first active material layer 12 applied can be divided into a first flat coating area 121 and a first thinned area 122 according to the coating thickness, wherein the thickness of the first flat coating area 121 is not less than the thickness of the first thinned area 122, and the thickness of the first flat coating area 121 remains basically consistent, while the thickness of the first thinned area 122 gradually becomes thinner from a position close to the first flat coating area 121 toward the direction of the first pole ear 112.

[0090] The first insulating layer 13 is separated from the first thinned area 122 , thereby improving the flexibility of the tab, reducing the risk of the insulating layer and active material falling off, and improving the reliability of the battery cell 100 .

[0091] The second insulating layer 14 is coated on the first thinned area 122. The second insulating layer 14 can be spaced apart from the first flat-coated area 121, thereby minimizing as much as possible the thickness increase on the first current collector 11 due to the coating of the second insulating layer 14, reducing the proportion of non-active substances in the battery cell 100, and improving the energy density of the battery cell 100.

[0092] As Figure 9 shown, in some embodiments, the maximum thickness of the first insulating layer 13 is H1, and 5 μm ≤ H1 ≤ 30 μm.

[0093] As Figure 9 shown, the first insulating layer 13 includes a flat-coated insulating section and an inclined insulating section. In the second direction F2, the flat-coated insulating section has a uniform thickness, and the thickness of the inclined insulating section gradually decreases in the direction away from the flat-coated insulating section. Thus, the thickness of the flat-coated insulating section is H1. Of course, the first insulating layer 13 may also include only the flat-coated insulating section, the flat-coated insulating section has a uniform thickness, and the thickness of the flat-coated insulating section is H1. Wherein, if H1 is too large, that is, the maximum thickness of the first insulating layer 13 is too large, it will increase the proportion of non-active substances in the battery cell 100 and reduce the energy density of the battery cell 100; if H1 is too small, the effect of improving the trimming burrs is not good.

[0094] Therefore, H1 can be limited between 5 μm and 30 μm. H1 can be any value among 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm or the range value between any two of them. By limiting H1 within the above range, the energy density of the battery cell 100 can be guaranteed to a certain extent, and at the same time, the burrs generated during the trimming of the electrode sheet can be reduced, thereby avoiding problems such as high self-discharge and short circuit caused by the burrs piercing the separator, and improving the comprehensive performance of the battery cell.

[0095] As Figure 9 shown, in some embodiments, the maximum thickness of the second insulating layer 14 is H2, and 5 μm ≤ H2 ≤ 30 μm.

[0096] As Figure 9As shown, the second insulating layer 14 includes a planar insulating section and an inclined insulating section. In the second direction F2, the planar insulating section has a uniform thickness, and the thickness of the inclined insulating section gradually decreases in the direction away from the planar insulating section. Thus, the thickness of the planar insulating section is H2. Of course, the second insulating layer 14 may also include only the planar insulating section, which has a uniform thickness, and the thickness of the planar insulating section is H2. Among them, if H2 is too large, that is, the maximum thickness of the second insulating layer 14 is too large, it will increase the proportion of non-active substances in the battery cell 100 and reduce the energy density of the battery cell 100; if H2 is too small, the effect of improving the cutting burrs is not good.

[0097] Therefore, H2 can be limited to be between 5 μm and 30 μm. H2 can be any value among 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm or the range value between any two of them. By limiting H2 within the above range, the energy density of the battery cell 100 can be guaranteed to a certain extent, and at the same time, the burrs generated during the cutting of the electrode sheet can be reduced, thereby avoiding problems such as high self-discharge and short circuit caused by the burrs piercing the separator, and improving the comprehensive performance of the battery cell.

[0098] As Figure 10 shown, in some embodiments, the electrode assembly 110 further includes a second electrode sheet 20. The second electrode sheet 20 is a negative electrode sheet, the first electrode sheet 10 is a positive electrode sheet. The second electrode sheet 20 includes a second current collector 21. The second current collector 21 includes a second main body portion 211 and a second tab 212. The second tab 212 protrudes from the second main body portion 211 in the first direction F1. The surface of the second main body portion 211 is coated with a second active material layer 22. Among them, in the first direction F1, the second active material layer 22 extends beyond both sides of the first active material layer 12.

[0099] As Figure 10 shown, the second electrode sheet 20 can be a negative electrode sheet, the first electrode sheet 10 is a positive electrode sheet. The length of the active material layer of the negative electrode sheet is greater than the length of the active material layer of the positive electrode sheet. For example, during the charging process of a lithium battery, lithium ions are removed from the positive electrode and embedded in the negative electrode. If the capacity of the negative electrode sheet is insufficient, the lithium ions cannot be completely embedded in the negative electrode, and lithium metal will precipitate on the surface of the negative electrode, forming lithium dendrites. The growth of lithium dendrites may penetrate the separator, resulting in an internal short circuit of the battery. Therefore, by making the active material layer of the negative electrode sheet extend beyond both sides of the active material layer of the positive electrode sheet, it is ensured that there is enough capacity to accept lithium ions and the phenomenon of lithium precipitation is avoided.

[0100] As Figure 10As shown, in some embodiments, in the first direction F1, the length of the first active material layer 12 is L1, and the length of the second active material layer 22 is L2, where 5 mm ≤ L2 - L1 ≤ 8 mm.

[0101] As Figure 10 shown, the second active material layer 22 of the negative electrode tab extends beyond both sides of the first active material layer 12 of the positive electrode tab, and the length L2 of the second active material layer 22 is greater than the length L1 of the first active material layer 12. Among them, if the difference between the two is too large, there will be a large amount of redundant area in the second active material layer 22 that is not effectively utilized, thereby reducing the energy density of the battery cell 100 and increasing the manufacturing cost of the battery cell 100; if the difference between the two is too small, the second active material layer 22 of the negative electrode tab cannot completely cover the first active material layer 12, resulting in lithium plating and triggering safety problems.

[0102] Therefore, L2 - L1 can be limited to be between 5 mm and 8 mm, and L2 - L1 can be any value among 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm or the range value between any two of them. By limiting L2 - L1 within the above range, the energy density of the battery cell 100 can be guaranteed to a certain extent, the manufacturing cost can be reduced, and at the same time, the probability of lithium plating can be reduced, and the reliability of the battery cell 100 can be improved.

[0103] The second aspect of the present application provides a battery 1000, which includes the battery cell 100 according to the embodiments of the present application. Thus, by adopting the above battery cell 100, the problems of ear wrinkling and insufficient ear flexibility caused by rolling can be balanced at the same time, the risk of insulation layer and active material material shedding can be reduced, and the reliability of the battery 1000 can be improved.

[0104] The third aspect of the present application provides an energy storage device 3000, which includes the battery 1000 according to the embodiments of the second aspect of the present application for storing electrical energy and capable of providing electrical energy.

[0105] Since the energy storage device includes the above battery 100, the use reliability of the battery and the energy storage device can be improved.

[0106] Next, a specific embodiment of the present application will be illustrated by way of example.

[0107] As Figure 2 shown, the battery 1000 includes a battery cell 100 and a box body 500. The battery cell 100 is arranged in the box body 500, and the battery cell 100 is a battery cell using a soft packaging film as a packaging body.

[0108] The electrode assembly 110 includes a first electrode tab 10 and a second electrode tab 20. The first electrode tab 10 includes a first current collector 11, and the first current collector 11 includes a first main body portion 111 and a first tab 112. The first tab 112 protrudes from the first main body portion 111 along a first direction F1. The second electrode tab 20 includes a second current collector 21, and the second current collector 21 includes a second main body portion 211 and a second tab 212. The second tab 212 protrudes from the second main body portion 211 along the first direction F1. The first tab 112 and the second tab 212 are located on opposite sides of the electrode assembly 110 in the first direction F1.

[0109] The surface of the first main body portion 111 is at least partially coated with a first active material layer 12; the surface of the second main body portion 211 is at least partially coated with a second active material layer 22.

[0110] The first electrode tab 10 further includes a first insulating layer 13, a second insulating layer 14, and a third insulating layer 15.

[0111] The first insulating layer 1,3 is coated on the first surface of the first electrode tab 10. A part of the first insulating layer 13 is coated on the first tab 112, and in the first direction F1, the first insulating layer 13 is arranged at an interval from the first active material layer 12.

[0112] The second insulating layer 14 is coated on the second surface of the first electrode tab 10. A part of the second insulating layer 14 is coated on the first tab 112, and in the first direction F1, a part of the second insulating layer 14 is coated on the first active material layer 12.

[0113] The third insulating layer 15 is coated on one end of the first main body portion 111 opposite to the first tab 112, and is coated on both the first side surface and the second side surface of the first main body portion 111. A part of the third insulating layer 15 is coated on the first active material layer 12.

[0114] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be covered by the scope of the claims and the description of the present application. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell (100), characterized in that, Comprising: An electrode assembly (110), the electrode assembly (110) includes a first pole piece (10), and the first pole piece (10) includes a first current collector (11). The first current collector (11) includes a first main body portion (111) and a first tab (112), the first tab (112) protrudes from the first main body portion (111) along a first direction, and two surfaces of the first main body portion (111) are respectively coated with a first active material layer (12). The first pole piece (10) further includes a first insulating layer (13) and a second insulating layer (14), the first insulating layer (13) and the second insulating layer (14) are respectively at least partially coated on opposite sides of the first tab (112), on one surface of the first pole piece (10), the first insulating layer (13) and the first active material layer (12) are arranged at intervals in the first direction, on the other surface of the first pole piece (10), the second insulating layer (14) is at least partially coated on the first active material layer (12).

2. The battery cell (100) according to claim 1, wherein In the first direction, the minimum distance between the edge of the first insulating layer (13) and the first active material layer (12) is D1, 10μm ≤ D1 ≤ 80μm.

3. The battery cell (100) according to claim 1, wherein The minimum dimension in the first direction of the portion of the second insulating layer (14) coating the first active material layer (12) is D2, 0 < D2 ≤ 600μm.

4. The battery cell (100) according to claim 1, wherein The first pole piece (10) further includes a third insulating layer (15), the third insulating layer (15) is coated on one end of the first main body portion (111) opposite to the first tab (112), and the third insulating layer (15) is at least partially coated on the first active material layer (12).

5. The battery cell (100) according to claim 4, wherein The minimum dimension in the first direction of the portion of the third insulating layer (15) coating the first active material layer (12) is D3, 0 < D3 ≤ 600μm.

6. The battery cell (100) according to claim 4, wherein The third insulating layer (15) is respectively coated on opposite sides of the first main body portion (111).

7. The battery cell (100) according to claim 1, wherein The first active material layer (12) includes a first flat coating area (121) and a first thinning area (122), the first thinning area (122) is closer to the first tab (112) than the first flat coating area (121), the first insulating layer (13) is arranged at intervals with the first thinning area (122), and the second insulating layer (14) coats at least a portion of the first thinning area (122).

8. The battery cell (100) according to claim 1, wherein The maximum thickness of the first insulating layer (13) is H1, where 5 μm ≤ H1 ≤ 30 μm.

9. The battery cell (100) according to claim 1, wherein The maximum thickness of the second insulating layer (14) is H2, where 5 μm ≤ H2 ≤ 30 μm.

10. The battery cell (100) according to any one of claims 1-9, wherein The electrode assembly (110) further includes a second electrode tab (20). The second electrode tab (20) is a negative electrode tab, and the first electrode tab (10) is a positive electrode tab. The second electrode tab (20) includes a second current collector (21). The second current collector (21) includes a second main body portion (211) and a second tab (212). The second tab (212) protrudes from the second main body portion (211) along a first direction. A second active material layer (22) is coated on the surface of the second main body portion (211). Wherein, in the first direction, the second active material layer (22) extends beyond both sides of the first active material layer (12).

11. The battery cell (100) according to claim 10, wherein In the first direction, the length of the first active material layer (12) is L1, and the length of the second active material layer (22) is L2, where 5 mm ≤ L2 - L1 ≤ 8 mm.

12. A battery (1000), characterized in that, Comprising the battery cell (100) according to any one of claims 1-11.

13. A energy storage device (3000), characterized in that, Comprising the battery (1000) according to claim 12.

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