Battery cell and battery pack

Abstract

The application provides a battery monomer and a battery pack, and relates to the technical field of batteries. The battery monomer comprises a shell, an end cover, an electrode assembly and a first binding layer; the end cover is connected with one end of the shell; the electrode assembly is arranged in the shell and comprises an electrode body, the electrode body comprises a first surface, a first end surface and a second surface which are sequentially connected, the first surface and the second surface are oppositely arranged, and the first end surface is arranged close to the end cover; the first binding layer is arranged in the shell and comprises a first binding part, the first binding part is arranged between the first surface and the second surface and is fixedly connected with the first end surface, the first binding part is provided with a plurality of first cutouts which are arranged in a penetrating mode, and the plurality of first cutouts are arranged in a spaced mode. When the electrode assembly is expanded, under the extrusion of the expansion force of the electrode assembly, the first binding part is prone to be broken at at least one first cutout, so that the risk that the electrode body is excessively bound is reduced, and the cycle performance of the battery monomer is improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a battery cell and a battery pack. Background Technology

[0002] The information disclosed in this background section is intended only to enhance the understanding of the general background of this disclosure and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art.

[0003] Battery cells are typically equipped with a binding layer, which is fixedly connected to the electrode body of the electrode assembly to reduce the risk of structural loosening of the electrode body during manufacturing and transportation. However, after long-term use, the electrode assembly is prone to expansion due to repeated charge and discharge cycles. At this time, the binding layer may over-bind the electrode body, thereby affecting the cycle performance of the battery cell. Utility Model Content

[0004] In view of this, the purpose of this application is to provide a battery cell and a battery pack, which aims to solve the technical problem that the binding layer easily over-binds the electrode body, thereby affecting the cycle performance of the battery cell.

[0005] To achieve the above objectives, the technical solution adopted in this application is as follows: In a first aspect, embodiments of this application provide a battery cell having a first direction and a second direction perpendicular to each other. The battery cell includes: a housing; an end cap connected to one end of the housing along the second direction; an electrode assembly disposed within the housing, the electrode assembly including an electrode body, the electrode body including a first surface, a first end face, and a second surface connected in sequence, the first surface and the second surface being disposed opposite each other along the first direction, the first end face being disposed close to the end cap along the second direction; and a first binding layer located within the housing, the first binding layer including a first binding portion, the first binding portion being located between the first surface and the second surface along the first direction, the first binding portion being fixedly connected to the first end face, and the first binding portion having a plurality of first cuts penetrating along the second direction, the plurality of first cuts being spaced apart along the first direction.

[0006] In some embodiments of the first aspect, the battery cell has a third direction that is mutually perpendicular to both the first direction and the second direction, and each first cut includes a plurality of first slits that penetrate along the second direction, the plurality of first slits being arranged along the third direction and connected end to end in sequence.

[0007] In some embodiments of the first aspect, the battery cell further includes a second binding layer located within the housing, and the electrode body further includes a second end face connected to the first surface and the second surface, the second end face being disposed away from the end cap along the second direction; the second binding layer is fixedly connected to the second end face, the second binding layer having a second cut through along the second direction, the second cut and the second end face being disposed opposite each other along the second direction.

[0008] In some embodiments of the first aspect, the battery cell has a third direction that is mutually perpendicular to both the first direction and the second direction, and there are multiple second cuts. The multiple second cuts are arranged at intervals along the first direction. The second cuts include multiple second slits that penetrate along the second direction. The multiple second slits are arranged along the third direction and connected end to end in sequence.

[0009] In some embodiments of the first aspect, the battery cell has a third direction that is mutually perpendicular to both the first direction and the second direction, and the electrode assembly further includes a first tab and a second tab, both of which extend from the first end face, the second tab and the first tab being arranged at intervals along the third direction, and the first binding portion being located between the first tab and the second tab along the third direction.

[0010] In some embodiments of the first aspect, there are multiple second binding layers, one of which is disposed opposite to the first tab along the second direction, and another of which is disposed opposite to the second tab along the second direction.

[0011] In some embodiments of the first aspect, the battery cell further includes a third binding layer located within the housing, the electrode body having a winding tail portion located on the first surface, the winding tail portion and the third binding layer both being located between the first tab and the second tab along the third direction, and the third binding layer being fixedly connected to the winding tail portion.

[0012] In some embodiments of the first aspect, the first binding layer further includes a second binding portion and a third binding portion connected to the first binding portion, the first binding portion being located between the second binding portion and the third binding portion along the first direction, the second binding portion being fixedly connected to the first surface, and the third binding portion being fixedly connected to the second surface.

[0013] In some embodiments of the first aspect, the third binding layer extends along the second direction and is fixedly connected to the second binding portion, the third binding layer being located on the side of the second binding portion away from the electrode body along the first direction.

[0014] Secondly, embodiments of this application provide a battery pack including the battery cells described in any of the embodiments of the first aspect above.

[0015] The beneficial effects of this application are as follows: The battery cell provided in this application has multiple first cuts extending along a second direction in the first binding portion of the first binding layer, with these first cuts spaced apart along a first direction. This design allows the first binding portion to easily break at at least one first cut when the electrode assembly expands, under the pressure of the expanding force. This reduces the risk of the electrode body being over-binded, thereby improving the cycle performance of the battery cell.

[0016] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A three-dimensional structural schematic diagram of a battery cell in an embodiment of this application is shown; Figure 2 It shows Figure 1 A schematic diagram of the assembly structure of the middle electrode assembly, the first binding layer, and the second binding layer from a single perspective; Figure 3 It shows Figure 1 Another view of the assembly structure of the middle electrode assembly, the first binding layer and the second binding layer; Figure 4 It shows Figure 3 Schematic diagram of the structure of the first binding layer; Figure 5 It shows Figure 1 Another perspective view of the assembly structure of the middle electrode assembly, the first binding layer, and the second binding layer; Figure 6 It shows Figure 5 Schematic diagram of the structure of the second binding layer; Figure 7It shows Figure 1 Another perspective view of the assembly structure of the middle electrode assembly, the first binding layer, and the second binding layer; Figure 8 It shows Figure 2 A schematic diagram of the structure when a third binding layer is provided and the electrode body has a wound tail section.

[0019] Explanation of key component symbols: 100 - Battery cell; 110 - Housing; 120 - End cap; 130 - Terminal post; 131 - First terminal post; 132 - Second terminal post; 140 - Electrode assembly; 141 - Tab; 1411 - First tab; 1412 - Second tab; 142 - Electrode body; 1421 - First surface; 1422 - First end face; 1423 - Second surface; 1424 - Second end face; 1425 - Winding tail section; 150 - First binding layer; 151 - Second binding section; 152 - Third binding section; 153 - First binding section; 154 - First cut; 1541 - First gap; 160 - Second binding layer; 161 - Second cut; 1611 - Second gap; 170 - Third binding layer; X - Third direction; Y - First direction; Z - Second direction. Detailed Implementation

[0020] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0021] In the description of this application, the terms "center", "longitudinal", "lateral", "length", "width", "height", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0022] Furthermore, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first and second features are in direct contact, or that they are in indirect contact through an intermediate medium. Moreover, "above" or "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below" or "below" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0023] In the description of this application, the terms "first," "second," etc., are used to distinguish different objects and should not be construed as indicating or implying a specific order or hierarchy, or implicitly specifying the number of technical features indicated. Therefore, a feature marked "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, the term "multiple" means two or more, unless otherwise explicitly defined.

[0024] In the description of this application, unless otherwise explicitly specified, the terms "installation," "connection," "attachment," etc., should be interpreted broadly. For example, they can refer to non-detachable connections (e.g., welding, riveting, etc.), detachable connections (e.g., snap-fit, screw-fit, plug-in, etc.), or integral structures; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0025] In the description of this application, the term "and / or" can be understood to mean three possibilities. For example, A and / or B can represent: A alone; A and B simultaneously; or B alone. Additionally, the character " / " generally indicates that the preceding and following objects have an "or" relationship.

[0026] In the description of this application, "parallel" includes not only the case of absolute parallelism, but also the case of approximate parallelism as commonly understood in engineering; similarly, "perpendicular" also includes not only the case of absolute perpendicularity, but also the case of approximate perpendicularity as commonly understood in engineering. For example, if the angle between two directions is 80° to 90°, the two directions can be considered perpendicular; if the angle between two directions is 0° to 10°, the two directions can be considered parallel.

[0027] In the description of this application, the term "fixed connection" can be understood as: two objects whose relative positions remain unchanged under normal use conditions, that is, they will not easily undergo relative movement (e.g., relative rotation and relative movement); for example, a fixed connection can be an adhesive connection, a screw connection, a snap-fit ​​connection, a welding connection, a riveting connection, a magnetic connection, a friction contact connection, or a one-piece molded structure, etc., without any specific limitations.

[0028] Battery cells are an important component of battery packs. Battery cells are typically equipped with a binding layer, which is wrapped around the electrode body connected to the electrode assembly to reduce the risk of structural loosening of the electrode assembly. However, after long-term use, the electrode assembly is prone to expansion due to repeated charge and discharge cycles. At this time, the binding layer may over-bind the electrode body, increasing the risk of electrode breakage and reducing the electrolyte retention capacity (i.e., the ability to retain electrolyte), thereby affecting the cycle performance of the battery cell.

[0029] like Figure 1 As shown, to solve the above-mentioned technical problems, embodiments of this application provide a battery cell 100, which relates to the field of battery technology and is mainly used in battery packs, so as to be indirectly used in electrical devices or energy storage devices in the form of battery packs. Of course, the battery cell 100 can also be directly used in electrical devices or energy storage devices without taking the form of a battery pack, and no specific limitation is made to the application scenarios of the battery cell 100 here.

[0030] For example, electrical devices can be vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools. Vehicles can be gasoline-powered cars, natural gas-powered cars, new energy vehicles, etc., and new energy vehicles can be pure electric vehicles, hybrid electric vehicles, range-extended electric vehicles, etc.; spacecraft can be airplanes, rockets, space shuttles, drones, spacecraft, etc.; electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys; power tools can be metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers; energy storage devices include energy storage containers, energy storage cabinets, energy storage power stations, wind power generation devices, solar power generation devices, mobile power devices, temporary power supply devices, etc.; no specific limitations are made on the types of electrical devices and energy storage devices here.

[0031] like Figures 1 to 3 as well as Figure 7 As shown, the battery cell 100 provided in this embodiment has a first direction Y and a second direction Z that are perpendicular to each other. The battery cell 100 includes: a housing 110, an end cap 120, an electrode assembly 140 and a first binding layer 150.

[0032] The end cap 120 is connected to one end of the housing 110 along the second direction Z. The electrode assembly 140 is disposed inside the housing 110. The electrode assembly 140 includes an electrode body 142. The electrode body 142 includes a first surface 1421, a first end face 1422, and a second surface 1423 connected in sequence. The first surface 1421 and the second surface 1423 are arranged opposite to each other along the first direction Y. The first end face 1422 is disposed close to the end cap 120 along the second direction Z. The first binding layer 150 is located inside the housing 110. The first binding layer 150 includes a first binding part 153. The first binding part 153 is located between the first surface 1421 and the second surface 1423 along the first direction Y. The first binding part 153 is fixedly connected to the first end face 1422. The first binding part 153 is provided with a plurality of first cuts 154 penetrating along the second direction Z. The plurality of first cuts 154 are arranged at intervals along the first direction Y.

[0033] It should be noted that "the first end face 1422 is set close to the end cap 120 along the second direction Z" can be understood as the first end face 1422 being located at one end of the electrode body 142 close to the end cap 120.

[0034] It is understood that the battery cell 100 provided in this embodiment has multiple first cuts 154 extending along the second direction Z in the first binding portion 153 of the first binding layer 150, and the multiple first cuts 154 are arranged at intervals along the first direction Y. In this way, when the electrode assembly 140 expands, under the pressure of the expansion force of the electrode assembly 140, the first binding portion 153 is more likely to break at at least one first cut 154, thereby reducing the risk of electrode breakage and decreased liquid retention capacity caused by excessive binding of the electrode body 142, and thus improving the cycle performance of the battery cell 100.

[0035] like Figure 1 , Figure 3 and Figure 4 As shown, in some embodiments, the battery cell 100 has a third direction X that is mutually perpendicular to the first direction Y and the second direction Z. Each first cut 154 includes a plurality of first slits 1541 that penetrate along the second direction Z. The plurality of first slits 1541 are arranged along the third direction X and connected end to end in sequence.

[0036] It is understandable that by using multiple first slits 1541 to form the first cut 154, the risk of the electrode body 142 being over-constrained can be reduced, and the area of ​​the electrode body 142 exposed at the first cut 154 can also be reduced. This helps to improve the ability of the electrode body 142 to retain electrolyte and helps to reduce the possibility of the active material in the electrode body 142 detaching from the electrode through the first cut 154.

[0037] like Figure 1 , Figure 2 Figure 5 and Figure 7 As shown, in some embodiments, the battery cell 100 further includes a second binding layer 160 located within the housing 110, and the electrode body 142 further includes a second end face 1424 connected to the first surface 1421 and the second surface 1423. The second end face 1424 is disposed away from the end cap 120 along the second direction Z. The second binding layer 160 is fixedly connected to the second end face 1424, and the second binding layer 160 has a second cut 161 extending along the second direction Z. The second cut 161 and the second end face 1424 are disposed opposite each other along the second direction Z. Specifically, both ends of the second binding layer 160 are fixedly connected to the first surface 1421 and the second surface 1423, which can more firmly fix the second binding layer 160 to the electrode body 142.

[0038] Understandably, the second binding layer 160 can bind the end of the electrode body 142 away from the end cap 120 along the second direction Z, reducing the possibility of the electrode body 142 becoming structurally loose. At the same time, when the electrode assembly 140 expands, the second binding part 151 is prone to break at the second cut 161 under the pressure of the expansion force of the electrode assembly 140, thereby reducing the risk of the electrode body 142 being over-bound, and improving the cycle performance of the battery cell 100.

[0039] like Figure 1 , Figure 5 and Figure 6 As shown, the battery cell 100 further has a third direction X that is perpendicular to both the first direction Y and the second direction Z. There are multiple second cuts 161, which are arranged at intervals along the first direction Y. Each second cut 161 includes multiple second slits 1611 that penetrate along the second direction Z. The multiple second slits 1611 are arranged along the third direction X and connected end to end in sequence.

[0040] Understandably, when the electrode assembly 140 expands, the second binding portion 151 is prone to breakage at at least one second cut 161 under the pressure of the expansion force of the electrode assembly 140, thereby further reducing the risk of the electrode body 142 being over-bound. By using multiple second gaps 1611 to form the second cut 161, the risk of the electrode body 142 being over-bound can be reduced, and the exposed area of ​​the electrode body 142 at the second cut 161 can also be reduced, thereby helping to improve the ability of the electrode body 142 to retain electrolyte and helping to reduce the possibility of the active material in the electrode body 142 detaching from the electrode body 142 through the second cut 161.

[0041] like Figure 1 , Figure 2and Figure 7 As shown, the battery cell 100 further has a third direction X that is mutually perpendicular to the first direction Y and the second direction Z. The electrode assembly 140 also includes a first tab 1411 and a second tab 1412. Both the first tab 1411 and the second tab 1412 extend from the first end face 1422. The second tab 1412 and the first tab 1411 are arranged at intervals along the third direction X. The first binding part 153 is located between the first tab 1411 and the second tab 1412 along the third direction X.

[0042] It should be noted that, since the second tab 1412 and the first tab 1411 are arranged at intervals along the third direction X, and the first binding part 153 is located between the first tab 1411 and the second tab 1412 along the third direction X, the first binding part 153 can avoid the first tab 1411 and the second tab 1412, thereby reducing the risk of structural interference between the first binding part 153 and the first tab 1411 and the second tab 1412.

[0043] Meanwhile, by placing the first binding part 153 between the first electrode tab 1411 and the second electrode tab 1412, the electrode body 142 can be more evenly stressed when bound by the first binding part 153, thus achieving higher structural stability.

[0044] like Figure 2 As shown, there are multiple second binding layers 160, one of which is arranged opposite to the first tab 1411 along the second direction Z, and the other is arranged opposite to the second tab 1412 along the second direction Z.

[0045] For example, the number of second binding layers 160 can be two, three, four, five, etc., without any specific limitation here.

[0046] It is understandable that when the structure of the electrode body 142 becomes loose, it can easily lead to instability in the structure of the first tab 1411 and the second tab 1412. By setting one of the multiple second binding layers 160 opposite to the first tab 1411 along the second direction Z, and setting another of the multiple second binding layers 160 opposite to the second tab 1412 along the second direction Z, the second binding layer 160 can not only bind the electrode body 142, but also stabilize the first tab 1411 and the second tab 1412, thereby reducing the risk of structural loosening of the first tab 1411 and the second tab 1412.

[0047] like Figure 1 and Figure 8As shown, the battery cell 100 further includes a third binding layer 170 located within the housing 110. The electrode body 142 has a winding tail portion 1425 located on the first surface 1421. The winding tail portion 1425 and the third binding layer 170 are both located between the first tab 1411 and the second tab 1412 along the third direction X. The third binding layer 170 is fixedly connected to the winding tail portion 1425.

[0048] For example, when the electrode assembly 140 is formed by winding a positive electrode, a negative electrode, and an insulating layer, the winding termination portion 1425 can be a part of the insulating layer, that is, the winding process of the electrode assembly 140 ends with the insulating layer; the winding termination portion 1425 can also be a part of the positive electrode or the negative electrode, that is, the winding process of the electrode assembly 140 ends with the positive electrode or the negative electrode; of course, the winding termination portion 1425 can also be a part of the positive electrode, a part of the negative electrode, and a part of the insulating layer, that is, the winding process of the electrode assembly 140 ends with the positive electrode, the negative electrode, and the insulating layer simultaneously. The structure of the winding termination portion 1425 is not specifically limited here.

[0049] Specifically, the first tab 1411 and the second tab 1412 are connected to the positive electrode and the negative electrode, respectively.

[0050] It is understandable that by using the third binding layer 170 to fix the winding tail portion 1425, the winding tail portion 1425 can be stabilized, thereby reducing the possibility of the electrode body 142 becoming loose due to the loosening of the winding tail portion 1425.

[0051] like Figure 1 , Figure 2 and Figure 7 As shown, the first binding layer 150 further includes a second binding portion 151 and a third binding portion 152 connected to the first binding portion 153. The first binding portion 153 is located between the second binding portion 151 and the third binding portion 152 along the first direction Y. The second binding portion 151 is fixedly connected to the first surface 1421, and the third binding portion 152 is fixedly connected to the second surface 1423.

[0052] It is understandable that the first binding part 153, the second binding part 151 and the third binding part 152 can form a mutual support between each other in the structure, and the binding effect covers the first surface 1421, the second surface 1423 and the first end face 1422 of the electrode body 142. This can more effectively bind the electrode body 142, thereby further reducing the risk of the electrode body 142 becoming structurally loose.

[0053] like Figure 7 and Figure 8As shown, the third binding layer 170 extends along the second direction Z and is fixedly connected to the second binding portion 151. The third binding layer 170 is located on the side of the second binding portion 151 away from the electrode body 142 along the first direction Y. This allows the third binding layer 170 and the first binding layer 150 to form a structural mutual support, which can more reliably and securely wind-up end portion 1425 and more reliably bind the electrode body 142.

[0054] It should be noted that the materials used in the various components of the battery cell 100 provided in this embodiment are as follows: For example, the materials of the first binding layer 150, the second binding layer 160, and the third binding layer 170 may be polyethylene terephthalate, polyimide, etc. In addition, adhesive may be coated on the surface of these substrates and dried and cured to make them sticky, thereby facilitating adhesion to the electrode body 142.

[0055] For example, the materials of the end cap 120 and / or the housing 110 can be aluminum, aluminum alloy, copper, iron, stainless steel, plastic, etc., without specific limitations.

[0056] For example, the material of the electrode 130 can be a metallic conductive material (e.g., copper, aluminum, silver, gold, iron, nickel, etc.) or a non-metallic conductive material (e.g., carbon-based materials, superconductors, semiconductors, etc.). Figure 1 As shown, when the electrode 130 includes a first electrode 131 and a second electrode 132, the first electrode 131 can be made of aluminum and the second electrode 132 can be made of copper, without any specific limitation.

[0057] It should be noted that the battery cell 100 provided in this embodiment mainly relies on the movement of metal ions between the positive and negative electrode plates to operate. The battery cell 100 can be cuboid, cylindrical, flat, or other shapes; according to the packaging method, the battery cell 100 provided in this embodiment can be a square battery, a cylindrical battery, a pouch battery, etc.; according to the type of metal ions, the battery cell 100 provided in this embodiment can be a lithium-ion battery, a sodium-ion battery, etc.

[0058] Furthermore, according to the classification of the physical state of the electrolyte, the battery cell 100 provided in this embodiment can be a liquid battery, that is, it uses a liquid electrolyte (i.e., electrolyte solution). Exemplarily, the electrode post 130 may include a first electrode post 131 and a second electrode post 132, one of which is a positive electrode post and the other a negative electrode post. The electrode assembly 140 can be manufactured using a winding process or a stacking process. The electrode assembly 140 may include an electrode body 142 and tabs 141. The tabs 141 include a first tab 1411 and a second tab 1412, one of which is a positive tab and the other a negative tab. The electrode body 142 is immersed in the liquid electrolyte and includes a first electrode, a second electrode, and a separator layer. One of the first electrode and the second electrode is a positive electrode, and the other is a negative electrode. The separator layer is disposed between the positive and negative electrode sheets, and the material of the separator layer can be polypropylene, polyethylene, etc. The positive electrode includes a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive current collector. The positive tab is connected to the positive current collector and also to the positive electrode post. The negative electrode includes 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 tab is connected to the negative current collector and also to the negative electrode post. Taking lithium ions as an example, the materials of the positive current collector and the positive tab can be aluminum, and the material of the positive active material layer can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, lithium manganese oxide, etc.; the materials of the negative current collector and the negative tab can be copper, and the negative active material can be graphite, silicon, etc.

[0059] Of course, the battery cell 100 provided in this embodiment can also be a solid-state battery, that is, a solid electrolyte, such as sulfide, oxide or polymer electrolyte. Solid electrolyte can replace the separator and liquid electrolyte, and has both ion conduction and isolation functions. The type of battery cell 100 is not specifically limited here.

[0060] To address the aforementioned technical problems, embodiments of this application also provide a battery pack, including the battery cell 100 from any of the above embodiments.

[0061] It is understood that since the battery pack provided in this embodiment has the battery cell 100 in any of the above embodiments, it has all the beneficial effects of the battery cell 100, which will not be described in detail here.

[0062] To better illustrate the beneficial effects of the embodiments of this application, some embodiments shown in the table below are provided for illustrative purposes:

[0063] I. Description of Embodiments: Embodiment 1: The battery cell 100 has a first binding layer 150 and a second binding layer 160. The first binding layer 150 has a first cut 154, and the second binding layer 160 has a second cut 161. Embodiment 2: The battery cell 100 has a first binding layer 150 and a second binding layer 160. The first binding layer 150 does not have a first cut 154, and the second binding layer 160 does not have a second cut 161. In Embodiments 1 and 2, the electrode assembly 140 of the battery cell 100 is manufactured by winding a positive electrode sheet, a negative electrode sheet, and a separator layer using a winding device, and undergoes the same baking, capacity testing, and other processes.

[0064] II. Cyclic Test Method: S1. Charge to 80% SOC (State of Charge) with a constant current of 2C; S2. Charge to 90% SOC with a constant current of 1C; S3. Charge to 3.65V with a constant current of 0.5C, then charge to 0.05C with a constant voltage; S4. Let stand for 30 minutes; S5. Discharge to 2.5V with a constant current of 2C; S6. Let stand for 30 minutes; Repeat steps S1 to S6 above, cycling for 2000 cycles.

[0065] III. Cyclic Test Results: As shown in the table above, when the cycle count is 1000, the capacity retention rate of Example 1 increases by 0.1% compared to Example 2; when the cycle count is 2000, the capacity retention rate of Example 1 increases by 1% compared to Example 2. It can be seen that by setting the first cut 154 and the second cut 161, the capacity retention rate of the battery cell 100 is improved, thus helping to improve the cycle performance of the battery cell 100.

[0066] In the description of this application, the terms "some embodiments," "one embodiment," "example," "specific example," "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In the description of this application, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0067] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A battery cell, characterized in that, The battery cell has a first direction (Y) and a second direction (Z) that are perpendicular to each other, and comprises: Casing (110); An end cap (120) is connected to one end of the housing (110) along the second direction (Z); An electrode assembly (140) is disposed within the housing (110). The electrode assembly (140) includes an electrode body (142). The electrode body (142) includes a first surface (1421), a first end face (1422), and a second surface (1423) connected in sequence. The first surface (1421) and the second surface (1423) are disposed opposite each other along the first direction (Y). The first end face (1422) is disposed close to the end cap (120) along the second direction (Z). The first binding layer (150) is located inside the housing (110). The first binding layer (150) includes a first binding portion (153). The first binding portion (153) is located between the first surface (1421) and the second surface (1423) along the first direction (Y). The first binding portion (153) is fixedly connected to the first end face (1422). The first binding portion (153) is provided with a plurality of first cuts (154) penetrating along the second direction (Z). The plurality of first cuts (154) are arranged at intervals along the first direction (Y).

2. The battery cell according to claim 1, characterized in that, The battery cell has a third direction (X) that is perpendicular to both the first direction (Y) and the second direction (Z). Each first cut (154) includes a plurality of first slits (1541) that penetrate along the second direction (Z). The plurality of first slits (1541) are arranged along the third direction (X) and connected end to end in sequence.

3. The battery cell according to claim 1, characterized in that, The battery cell further includes a second binding layer (160) located within the housing (110), and the electrode body (142) further includes a second end face (1424) connected to the first surface (1421) and the second surface (1423). The second end face (1424) is disposed away from the end cap (120) along the second direction (Z). The second binding layer (160) is fixedly connected to the second end face (1424). The second binding layer (160) is provided with a second cut (161) penetrating along the second direction (Z). The second cut (161) and the second end face (1424) are disposed opposite to each other along the second direction (Z).

4. The battery cell according to claim 3, characterized in that, The battery cell has a third direction (X) that is perpendicular to both the first direction (Y) and the second direction (Z). There are multiple second cuts (161), which are spaced apart along the first direction (Y). Each second cut (161) includes multiple second slits (1611) that penetrate along the second direction (Z). The multiple second slits (1611) are arranged along the third direction (X) and connected end to end in sequence.

5. The battery cell according to claim 3, characterized in that, The battery cell has a third direction (X) that is perpendicular to both the first direction (Y) and the second direction (Z). The electrode assembly (140) further includes a first tab (1411) and a second tab (1412). Both the first tab (1411) and the second tab (1412) extend from the first end face (1422). The second tab (1412) and the first tab (1411) are arranged at intervals along the third direction (X). The first binding part (153) is located between the first tab (1411) and the second tab (1412) along the third direction (X).

6. The battery cell according to claim 5, characterized in that, There are multiple second binding layers (160), one of which is arranged opposite to the first tab (1411) along the second direction (Z), and another of which is arranged opposite to the second tab (1412) along the second direction (Z).

7. The battery cell according to claim 5, characterized in that, The battery cell also includes a third binding layer (170) located within the housing (110). The electrode body (142) has a winding tail portion (1425) located on the first surface (1421). The winding tail portion (1425) and the third binding layer (170) are both located in the third direction (X) between the first tab (1411) and the second tab (1412). The third binding layer (170) is fixedly connected to the winding tail portion (1425).

8. The battery cell according to claim 7, characterized in that, The first binding layer (150) further includes a second binding portion (151) and a third binding portion (152) connected to the first binding portion (153). The first binding portion (153) is located between the second binding portion (151) and the third binding portion (152) along the first direction (Y). The second binding portion (151) is fixedly connected to the first surface (1421), and the third binding portion (152) is fixedly connected to the second surface (1423).

9. The battery cell according to claim 8, characterized in that, The third binding layer (170) extends along the second direction (Z) and is fixedly connected to the second binding portion (151). The third binding layer (170) is located on the side of the second binding portion (151) away from the electrode body (142) along the first direction (Y).

10. A battery pack, characterized in that, Includes the battery cell according to any one of claims 1 to 9.

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