Battery cell, lithium battery, electric equipment and battery cell preparation method

Abstract

The invention relates to the technical field of lithium batteries, in particular to a battery cell, a lithium battery, electric equipment and a battery cell preparation method. The battery cell comprises a first pole piece, a second pole piece and a diaphragm, first coating areas and first blank areas of the first pole piece are alternately arranged in the length direction of the first pole piece, first active material layers are arranged on the first coating areas, second coating areas and second blank areas of the second pole piece are alternately arranged in the length direction of the second pole piece, and second active material layers are arranged on the second coating areas. A second active material layer is arranged on the second coating area, the second pole piece, the diaphragm and the first pole piece are sequentially stacked and then wound to form a plurality of stacked energy storage units, and the first blank area and the second blank area are located at the winding positions of every two adjacent energy storage units. According to the battery cell, the lithium battery, the electric equipment and the battery cell preparation method provided by the invention, the production efficiency of the battery cell can be effectively improved while relatively high space utilization rate and stable internal structure are realized.

Description

Technical Field

[0001] This application relates to the field of lithium battery technology, and in particular to battery cells, lithium batteries, electrical devices, and methods for preparing battery cells. Background Technology

[0002] Lithium-ion batteries, as a green and clean energy source, are widely used in consumer electronics and new energy vehicles. Currently, lithium-ion battery manufacturing methods are divided into wound and stacked types. Wound batteries are made by winding continuous positive and negative electrode sheets separated by a separator. This method has high production efficiency and yield, but low volume utilization and unstable internal structure. Stacked batteries, on the other hand, involve cutting and stacking positive and negative electrode sheets sequentially, separated by a separator. This method has high volume utilization and stable internal structure, but slow stacking speed and low production efficiency. Therefore, improving the efficiency of lithium-ion battery manufacturing while achieving high volume utilization and structural stability is a current research focus. Summary of the Invention

[0003] This application discloses a battery cell, a lithium battery, an electrical device, and a method for manufacturing the battery cell, which can effectively improve the production efficiency of the battery cell while achieving high space utilization and stable internal structure.

[0004] To achieve the above objectives, in a first aspect, this application discloses a battery cell comprising:

[0005] The first electrode sheet is a long strip-shaped sheet. The first electrode sheet has multiple first coated areas and multiple first blank areas. The first coated areas and the first blank areas are alternately arranged along the length direction of the first electrode sheet. A first active material layer is provided on the first coated area.

[0006] A second electrode sheet, the second electrode sheet being elongated and sheet-shaped, having multiple second coated areas and multiple second blank areas, each second blank area corresponding to a first blank area, the second coated areas and second blank areas being alternately arranged along the length direction of the second electrode sheet, and a second active material layer being provided on the second coated areas; and

[0007] A diaphragm, wherein the diaphragm is separated between the first electrode and the second electrode;

[0008] The first electrode, the diaphragm, and the second electrode are sequentially stacked and wound to form multiple stacked energy storage units. The first blank area and the second blank area are both located at the winding points of two adjacent energy storage units.

[0009] In this configuration, one of the first electrode and the second electrode is a positive electrode, and the other is a negative electrode.

[0010] In some possible implementations, both the first electrode and the second electrode have a beginning and an end along the length direction of the first electrode;

[0011] Along the length of the first electrode, the width of the first blank area and the width of the second blank area both gradually increase from the beginning to the end.

[0012] In some possible implementations, along the length direction of the first electrode, the width of each of the first blank areas is equal to the width of the corresponding second blank areas;

[0013] The width of the first blank area satisfies: W=π*(A+(n-1)*(B+C+2D)) / 2, where A is the thickness of the winding needle, B is the thickness of the first electrode, C is the thickness of the second electrode, D is the thickness of the diaphragm, and n is the number of winding layers.

[0014] In some possible implementations, when the first electrode is a positive electrode, the width of the second coating area is greater than the width of the first coating area along the length direction.

[0015] In some possible implementations, the first electrode has two opposing surfaces, each of which has a plurality of the first coated areas and a plurality of the first blank areas;

[0016] And / or,

[0017] The second electrode has two opposing surfaces, and each of the two surfaces of the second electrode is provided with a plurality of second coating areas and a plurality of second blank areas.

[0018] In some possible implementations, the first electrode has a start end and an end end along its length, and when both surfaces of the first electrode have the first coating area and the first blank area, the first coating area closest to the end on one of the surfaces is not provided with the first active material layer.

[0019] In some possible implementations, the first electrode sheet is provided with a plurality of first electrode tabs, the second electrode sheet is provided with a plurality of second electrode tabs, the plurality of wound first electrode tabs are stacked on top of each other, and the plurality of wound second electrode tabs are stacked on top of each other.

[0020] Secondly, this application also discloses a lithium battery, which includes a casing and a cell as described in the first aspect above, the cell being disposed within the casing.

[0021] Thirdly, this application also discloses an electrical device that includes a lithium battery as described in the second aspect above.

[0022] Fourthly, this application also discloses a method for preparing a battery cell, the method comprising:

[0023] A first electrode is provided, which is a long strip. The first electrode has multiple first coated areas and multiple first blank areas. The first coated areas and the first blank areas are alternately arranged along the length direction of the first electrode. A first active material layer is provided on the first coated area.

[0024] A second electrode is provided, which is a long strip. The second electrode has multiple second coating areas and multiple second blank areas. Each second blank area is respectively disposed corresponding to each first blank area. The second coating areas and the second blank areas are alternately disposed along the length direction of the second electrode. A second active material layer is disposed on the second coating area.

[0025] A diaphragm is provided to separate the first electrode and the second electrode;

[0026] The first electrode, the diaphragm, and the second electrode are stacked in sequence and then wound using a winding needle to form a battery cell.

[0027] In this configuration, one of the first electrode and the second electrode is a positive electrode, and the other is a negative electrode.

[0028] Compared with the prior art, the beneficial effects of this application are:

[0029] This application provides a battery cell, a lithium battery, an electrical device, and a method for manufacturing the battery cell. The battery cell includes a first electrode, a second electrode, and a separator. A first coated area and a first blank area of ​​the first electrode are alternately arranged along the length of the first electrode. A first active material layer is provided on the first coated area. A second coated area and a second blank area of ​​the second electrode are alternately arranged along the length of the second electrode. A second active material layer is provided on the second coated area. The second electrode, the separator, and the first electrode are sequentially stacked and then wound to form multiple stacked energy storage units. The first blank area and the second blank area are located at the winding points of two adjacent energy storage units. By setting the first blank area and the second blank area, the battery cell can form a stacked structure after winding. Thus, the battery cell has both the stacked structure of a laminated battery cell and can be produced by winding, thereby achieving high space utilization and internal structural stability while improving battery cell production efficiency. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the structure of a square battery cell in related technologies;

[0032] Figure 2 This is a schematic diagram of the battery cell structure provided in an embodiment of this application;

[0033] Figure 3 This is a schematic diagram of the structure of the first electrode sheet before winding, provided in an embodiment of this application.

[0034] Figure 4 This is a schematic diagram of the structure of the second electrode sheet before winding, provided in an embodiment of this application.

[0035] Figure 5 This is a schematic diagram of the structure of a lithium battery provided in an embodiment of this application;

[0036] Figure 6 This is a schematic diagram of the structure of the electrical equipment provided in the embodiments of this application;

[0037] Figure 7 A flowchart illustrating the cell manufacturing method provided in this application embodiment.

[0038] Explanation of reference numerals in the attached figures:

[0039] 100-Battery cell; 1-First electrode; 11-First coating area; 111-First active material layer; 12-First blank area; 13-First tab; 14-Starting end; 15-Ending end; 2-Second electrode; 21-Second coating area; 211-Second active material layer; 22-Second blank area; 23-Second tab; 3-Energy storage unit; F1-Length direction of the first electrode; F2-Length direction of the second electrode; 200-Lithium battery; 201-Casing; 300-Electrical device. Detailed Implementation

[0040] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0041] In this application, the terms "inner" and the like indicate orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0042] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0043] Furthermore, the terms "set up" and "equipped with" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0044] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, elements, or components (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, elements, or components. Unless otherwise stated, "a plurality of" means two or more.

[0045] Lithium-ion batteries, as a green and clean energy source, possess the characteristics of being environmentally friendly, highly efficient, and rechargeable, playing a crucial role in the pursuit of lightweight design and long battery life in consumer electronics and the new energy vehicle industry. In lithium-ion battery manufacturing processes, preparation is divided into winding and stacking processes. Simply put, the winding process involves separating the positive and negative electrode sheets on both sides of a separator, winding them using equipment or manually, and then fixing the cell with adhesive tape after winding before moving it to the next process. Pouch cells, prismatic cells, and cylindrical cells can all be manufactured using the winding process. The winding process enables rapid production line flow, effectively improving production efficiency, and also reduces production costs and increases yield through large-scale production. The stacking process, on the other hand, involves pre-die-cutting the positive and negative electrode sheets, and then stacking the positive electrode sheets, separator, and negative electrode sheets layer by layer to form prismatic or pouch cells.

[0046] Please see Figure 1 , Figure 1 (a) is a stacked cell. Figure 1(b) is a wound battery. Compared to wound batteries, stacked batteries achieve higher space utilization due to the absence of winding or bending points, and their internal structure is uniform, resulting in relatively consistent reaction rates. Furthermore, stacked batteries feature a multi-electrode parallel design, leading to lower internal resistance and enabling high-current charging and discharging in a short time, thus improving the rate performance of lithium batteries. However, the stacking process requires sequentially stacking multiple negative and positive electrodes to achieve the stacked battery structure, which consumes significant time and effort, reducing production efficiency. Moreover, compared to wound batteries, stacked batteries require cutting the electrodes at four locations, resulting in more prominent burrs on the electrodes and consequently lower yield rates.

[0047] In view of this, the embodiments of this application provide a battery cell, a lithium battery, an electrical device, and a method for manufacturing a battery cell, which can effectively improve the battery cell production efficiency and yield while achieving high space utilization and internal structural stability.

[0048] The technical solution of this application will be further described below with reference to the embodiments and accompanying drawings.

[0049] Please refer to the following: Figures 2-4 , Figure 2 This is a schematic diagram of the battery cell structure provided in an embodiment of this application. Figure 3 This is a schematic diagram of the structure of the first electrode sheet before winding, as provided in an embodiment of this application. Figure 4 This is a schematic diagram of the structure of the second electrode sheet before winding, as provided in an embodiment of this application. In a first aspect, an embodiment of this application provides a battery cell 100, which includes a first electrode sheet 1, a second electrode sheet 2, and a separator (not shown). The first electrode sheet 1 is elongated and has multiple first coating areas 11 and multiple first blank areas 12, which are alternately arranged along the length direction F1 of the first electrode sheet 1. A first active material layer 111 is provided on the first coating area 11. The second electrode sheet 2 is elongated and has multiple second coating areas 21 and multiple second blank areas 22, each second blank area 22 corresponding to a specific first blank area 12. The second coating areas 21 and second blank areas 22 are alternately arranged along the length direction F2 of the second electrode sheet 2. A second active material layer 211 is provided on the second coating area 21. The separator is disposed between the first electrode sheet 1 and the second electrode sheet 2. Multiple stacked energy storage units 3 are formed by sequentially stacking the second electrode 2, the separator, and the first electrode 1 and then winding them. The first blank area 12 and the second blank area 22 are located at the winding points of two adjacent energy storage units 3. One of the first electrode 1 and the second electrode 2 is a positive electrode, and the other is a negative electrode. That is, when the first electrode 1 is a positive electrode, the second electrode 2 is a negative electrode; or, when the first electrode 1 is a negative electrode, the second electrode 2 is a positive electrode.

[0050] It is understood that the aforementioned first blank area 12 and second blank area 22 refer to areas where no active material is coated. That is, the first active material layer 111 is not provided on the first blank area 12, and the second active material layer 211 is not provided on the second blank area 22.

[0051] It is understandable that when the first active material layer 111 is provided on the first coating area 11, the first active material layer 111 can completely cover the first coating area 11, that is, the first blank area 12 is formed as the interval area between two adjacent first active material layers 111.

[0052] Correspondingly, when a second active material layer 211 is provided on the second coating area 21, the second active material layer 211 can completely cover the second coating area 21, thereby forming the second blank area 22 as the interval area between two adjacent second active material layers 211.

[0053] It is understandable that when the first electrode 1 is a positive electrode, the first active material layer 111 is a positive active material layer, and correspondingly, the second active material layer 211 is a negative active material layer, and vice versa.

[0054] The embodiments of this application will be described below using the first electrode 1 as the positive electrode and the second electrode 2 as the negative electrode as an example.

[0055] By designing the distribution positions of the corresponding first coating area 11 and second coating area 21 on the first electrode 1 and the second electrode 2, the battery cell 100 can be directly wound using a winding device, thereby effectively improving the manufacturing efficiency. Furthermore, the first active material layer 111 on the first electrode 1 and the second active material layer 211 on the second electrode 2 are correspondingly arranged to form an energy storage unit 3. The first blank area 12 and the second blank area 22 are both located at the winding points of two adjacent energy storage units 3, enabling the battery cell 100 to form a stacked structure. The winding points of the battery cell 100 do not occupy the internal space of the lithium battery 200, effectively improving the volume utilization rate of the battery cell 100. The internal structure is uniform, the reaction rate is relatively consistent, and the internal structural stability is higher. Simultaneously, the battery cell 100 experiences uniform stress, avoiding bending at both ends and reducing the possibility of deformation.

[0056] Optionally, both the first electrode 1 and the second electrode 2 have a beginning end 14 and an end end 15 along the length direction F1 of the first electrode 1, and along the length direction F1 of the first electrode 1, the width of the first blank area 12 and the width of the second blank area 22 gradually increase from the beginning end 14 to the end end 15. Since the thickness of the cell 100 of the lithium battery 200 gradually increases with the increase of the number of winding layers, in order to ensure that the first blank area 12 and the second blank area 22 can be set correspondingly and located at the winding point, the width of the first blank area 12 and the second blank area 22 along the length direction F1 of the first electrode 1 needs to be gradually increased with the increase of the number of winding layers. This ensures that the first blank area 12 and the second blank area 22 are located at the winding points of two adjacent energy storage units 3, and each second blank area 22 is set corresponding to each first blank area 12. This reduces or avoids the generation of redundant first blank areas 12 or second blank areas 22, making the internal structure of the cell 100 compact, which is beneficial to improving the internal volume utilization of the cell 100, thereby improving the charging and discharging performance of the lithium battery 200 cell 100.

[0057] For example, Figure 3 and Figure 4 As shown in the figure, it can be seen that the width of the multiple first blank areas 12 gradually increases along the direction from the beginning 14 to the end 15, and correspondingly, the width of the multiple second blank areas 22 also gradually increases.

[0058] Considering that the first blank area 12 is actually formed as the interval between two first coated areas 11, and the second blank area 22 is actually formed as the interval between two second coated areas 21, it is necessary to design the width of the first blank area 12 and the second blank area 22. Optionally, along the length direction F1 of the first electrode 1, the width of each first blank area 12 is opposite to the width of the corresponding second blank area 22, and the widths of the multiple first blank areas 12 and the multiple second blank areas 22 gradually increase from the beginning end 14 to the end end 15. Taking the first blank area 12 as an example, the width W of the first blank area 12 along the length direction F1 of the first electrode 1 satisfies: W=π*(A+(n-1)*(B+C+2D)) / 2, where A is the thickness of the winding needle, B is the thickness of the first electrode 1, C is the thickness of the second electrode 2, D is the thickness of the diaphragm, and n is the number of winding layers. That is to say, the width of the first blank area 12 along the length direction F1 of the first electrode 1 is equal to the width of the second blank area 22 along the length direction F1 of the first electrode 1. As the number of winding layers increases, the thickness of the cell 100 gradually increases. Also, the first blank area 12 and the second blank area 22 need to be set at the winding points of two adjacent energy storage units 3. Therefore, the width of the first blank area 12 along the length direction F1 of the first electrode 1 and the width of the second blank area 22 along the length direction F1 of the first electrode 1 need to satisfy π*(thickness of the winding needle + (number of winding layers - 1)*(thickness of the first electrode 1 + thickness of the second electrode 2 + 2*thickness of the separator)) / 2, so that when the thickness of the cell 100 increases with the increase of the number of winding layers, the first blank area 12 and the second blank area 22 can still be correspondingly set at the winding points of two adjacent energy storage units 3, avoiding the generation of arc at the winding corners in the winding process, making the internal structure of the cell 100 more compact and stable, and at the same time, the volume utilization rate of the lithium battery 200 is higher, which can make full use of the corner space of the lithium battery 200 and further improve the energy density of the cell 100.

[0059] In some embodiments, when the first electrode 1 is a positive electrode, the width of the second coating area 21 along the length direction F1 of the first electrode 1 and along the length direction F2 of the second electrode 2 is greater than the width of the first coating area 11 along the length direction F1 of the first electrode 1. This is because during the charging and discharging process of the lithium battery 200, lithium ions migrate between the first active material layer 111 and the second active material layer 211. The diffusion ability of lithium ions in the negative electrode crystal structure is better than that in the positive electrode crystal structure. Lithium ions can diffuse in the second active material layer 211 faster and better, thereby improving the diffusion ability and storage capacity of lithium ions in the second active material layer 211, and thus improving the performance and safety of the lithium battery 200.

[0060] Please refer to it again. Figure 2In some embodiments, to further improve the overall performance of the lithium battery 200, at least one of the first electrode 1 and the second electrode 2 can be configured with a double-sided coating design. For example, both the first electrode 1 and the second electrode 2 have two opposing surfaces along the thickness direction. The two surfaces of the first electrode 1 are each provided with a plurality of first coating areas 11, and the two surfaces of the second electrode 2 are each provided with a plurality of second coating areas 21. The first coating areas 11 are coated with a first active material layer 111, and the second coating areas are coated with a second active material layer 211. That is to say, double-sided coating of the first electrode 1 and the second electrode 2 can achieve higher energy storage capacity in a smaller volume. Furthermore, during the double-sided coating process, the coating slurry, drying times, and moisture content on both sides are highly consistent, resulting in good uniformity on both surfaces of the electrode, which is beneficial for improving the overall performance of the lithium battery 200.

[0061] It is understood that, in addition to the aforementioned provision that the first electrode 1 has multiple first coating areas 11 on both surfaces and the second electrode 2 has multiple second coating areas 21 on both surfaces, other examples are also possible, such as the first electrode 1 having multiple first coating areas 11 on both surfaces or the second electrode 2 having multiple second coating areas 21 on both surfaces. This application embodiment does not limit this.

[0062] Optionally, the first electrode 1 has two opposing surfaces along the thickness direction. Each surface has a first coated area 11 and a first blank area 12. The first coated area 11 and the first blank area 12 on the two surfaces are alternately arranged from the beginning end 14 to the end end 15. On one surface, the first coated area 11 closest to the end 15 is not coated with the first active material layer 111. This is because when the battery cell 100 is wound, it is first pre-wound by two layers of separators, then the beginning end of the second electrode 2 is inserted between the separators for half a turn of pre-wound, and finally the first electrode 1 is wound. The second electrode 2, the diaphragm, and the first electrode 1 are stacked in sequence and wound into a winding needle. The end 15 of the first electrode 1 serves as the final section of the winding of the battery cell 100. The first active material layer 111 on the surface of the first electrode 1 away from the winding needle does not have a second active material layer 211 that reacts with it. Therefore, the first active material layer 111 is not coated on the first coating area 11 at the position closest to the end 15 on this surface, which can reduce the use of the first active material, thereby reducing the coating steps of the first electrode 1 and the production cost.

[0063] It is understandable that, since one of the first electrode 1 and the second electrode 2 is a positive electrode and the other is a negative electrode, and the winding order of the positive and negative electrodes of the cell 100 is not limited, the positive electrode coating area of ​​the positive electrode or the negative electrode coating area of ​​the negative electrode can be set according to the winding order. For example, when the first electrode 1 is a positive electrode, that is, the second electrode 2 is a negative electrode, the positive electrode has two opposing surfaces along the thickness direction. Both surfaces have a positive electrode coating area and a positive electrode blank area. The positive electrode coating area and the positive electrode blank area on the two surfaces are alternately arranged from the beginning to the end of the positive electrode. The positive electrode coating area closest to the end on one of the surfaces is not coated with a positive electrode active material layer. During the winding process of the battery cell 100, two layers of separators are first pre-wound. Then, the beginning of the negative electrode sheet is inserted between the two layers of separators for half a turn of pre-winding. Finally, the positive electrode sheet enters the winding process and is separated from the negative electrode sheet by the separator. Since the negative electrode sheet, separator, and positive electrode sheet are stacked in sequence and wound into the winding needle, and the end of the positive electrode sheet serves as the end of the battery cell winding, the positive active material layer on the surface of the positive electrode sheet away from the winding needle does not have a negative active material layer that can react with it. Therefore, by not coating the positive active material layer on the positive coating area closest to the end of this surface, the use of positive active material can be reduced, thereby reducing the coating steps and production costs of the positive electrode sheet.

[0064] Similarly, when the first electrode 1 is the negative electrode, that is, the second electrode 2 is the positive electrode, the negative electrode has two opposing surfaces along the thickness direction. Both surfaces have a negative electrode coating area and a negative electrode blank area. The negative electrode coating area and negative electrode blank area on the two surfaces are alternately arranged from the beginning to the end of the negative electrode. The negative electrode coating area closest to the end on one of the surfaces is not coated with a negative electrode active material layer. During the winding process of the battery cell 100, the two layers of separators are first pre-wound. Then, the beginning of the positive electrode is inserted between the two layers of separators for half a turn of pre-winding. Finally, the negative electrode enters the winding and is separated from the positive electrode by the separator. Since the positive electrode, separator, and negative electrode are stacked in sequence and wound into the winding needle, and the end of the negative electrode serves as the winding end of the cell 100, the negative electrode active material layer on the surface of the negative electrode away from the winding needle does not have a positive electrode active material layer that can react with it. Therefore, by not coating the negative electrode active material layer on the negative electrode coating area closest to the end of this surface, the use of negative electrode active material can be reduced, thereby reducing the coating steps and production costs of the negative electrode.

[0065] Please see Figure 5 , Figure 5This is a schematic diagram of the structure of a lithium battery provided in an embodiment of this application. In some embodiments, the first electrode 1 has multiple first tabs 13, and the second electrode 2 has multiple second tabs 23. The wound first tabs 13 and the wound second tabs 23 are stacked on top of each other. By providing multiple tabs on the first electrode 1 and the second electrode 2, the charging efficiency can be effectively improved, the internal resistance of the lithium battery 200 can be reduced, and the situation of excessively rapid temperature rise during charging can be reduced, thereby improving the safety of the lithium battery 200 and extending its service life.

[0066] It is understandable that the method for obtaining the electrode die-cutting position parameters can be as follows: the first electrode 1, the separator, and the second electrode 2 are stacked and wound in sequence to form a battery cell 100. The electrode area of ​​the battery cell 100 is cut according to the preset electrode shape and size to form the first electrode 13 and the second electrode 23. The battery cell 100 with electrodes is then disassembled into electrode sheets, and the winding start position information of the first electrode 1 and the second electrode 2 after disassembly is recorded. Based on the winding start position information, the die-cutting position parameters of the first electrode 13 and the second electrode 23 after disassembly are measured, and these are used as the final electrode die-cutting position parameters of the battery cell 100.

[0067] Secondly, this application also provides a lithium battery 200, which includes a casing 201 and a battery cell 100 as described in the first aspect, with the battery cell 100 disposed within the casing 201. Exemplarily, the casing 201 can be an aluminum-plastic film casing, an aluminum alloy casing, a plastic casing, etc., and this embodiment does not limit this. The battery cell 100 is the same as the battery cell 100 mentioned in the first aspect, and therefore can bring the same or similar beneficial effects. For details, please refer to the description of the battery cell 100 in the above embodiments; this application embodiment will not repeat it here.

[0068] Please see Figure 6 , Figure 6 This is a schematic diagram of the structure of an electrical device provided in an embodiment of this application. In a third aspect, this application also provides an electrical device 300, which includes the lithium battery 200 described in the second aspect above. The structure of the lithium battery 200 is the same as that of the lithium battery 200 in the above embodiments, and it can bring the same or similar beneficial effects. For details, please refer to the description of the lithium battery 200 in the above embodiments; further details will not be repeated here.

[0069] Specifically, the electrical equipment 300 may include, but is not limited to, vehicles, energy storage systems, and electronic products (such as mobile phones, desktop computers, learning machines, watches, laptops, tablets, etc.), and this application embodiment does not limit this.

[0070] Please see Figure 7 , Figure 7A flowchart illustrating the cell fabrication method provided in this application embodiment. In a fourth aspect, this application embodiment also provides a method for fabricating a cell 100 according to the first aspect above, the cell 100 fabrication method comprising:

[0071] 401. Provide the first electrode.

[0072] Optionally, the first electrode 1 is a strip-shaped sheet, and the first electrode 1 has a plurality of first coating areas 11 and a plurality of first blank areas 12. The first coating areas 11 and the first blank areas 12 are alternately arranged along the length direction F1 of the first electrode 1, and a first active material layer 111 is provided on the first coating area 11.

[0073] For example, the first electrode 1 can be a positive electrode or a negative electrode, and the first active material layer 111 can be a positive active material layer or a negative active material layer.

[0074] 402. Provide a second electrode.

[0075] Optionally, the second electrode 2 is a strip-shaped sheet. The second electrode 2 has multiple second coating areas 21 and multiple second blank areas 22. Each second blank area 22 is respectively provided corresponding to each first blank area 12. The second coating areas 21 and the second blank areas 22 are alternately arranged along the length direction F2 of the second electrode 2. A second active material layer 211 is provided on the second coating area 21.

[0076] It is understandable that either the first electrode 1 or the second electrode 2 can be a positive electrode, and the other can be a negative electrode. Correspondingly, either the first active material layer 111 or the second active material layer 211 can be a positive active material layer, and the other can be a negative active material layer.

[0077] 403. Provide a diaphragm to separate the first electrode from the second electrode.

[0078] In this step, the separator separates the first electrode 1 and the second electrode 2, preventing current from circulating directly through the first electrode 1 and the second electrode 2, thereby preventing a short circuit in the lithium battery 200. At the same time, the separator allows lithium ions to pass through while blocking electrons, thus allowing lithium ions to move freely inside the cell 100 and preventing electron loss and overheating of the lithium battery 200.

[0079] 404. The first electrode, the separator, and the second electrode are stacked in sequence and then wound using a winding needle to form a battery cell.

[0080] It is understood that, considering that the battery cell 100 of this application is a square battery cell, the cross-sectional shape of the winding needle can be rectangular, that is, the winding needle can be a square winding needle, so that the battery cell 100 obtained by the battery cell 100 preparation method is a square battery cell.

[0081] As can be seen, the method for preparing the cell 100 provided in this application involves sequentially stacking the first electrode 1, the separator, and the second electrode 2 and then winding them to form multiple stacked energy storage units 3. The first blank area 12 and the second blank area 22 are both located at the winding points of two adjacent energy storage units 3, making the structure of the cell 100 a stacked structure. Furthermore, the winding points of the cell 100 do not occupy the internal space of the lithium battery 200, thereby effectively improving the volume utilization rate of the cell 100. The internal structure is also stable and not easily deformed, effectively improving the energy density and charge / discharge performance of the lithium battery 200.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A battery cell, characterized in that, include: The first electrode sheet is a long strip-shaped sheet. The first electrode sheet has multiple first coated areas and multiple first blank areas. The first coated areas and the first blank areas are alternately arranged along the length direction of the first electrode sheet. A first active material layer is provided on the first coated area. The second electrode is a long strip-shaped sheet. The second electrode has multiple second coating areas and multiple second blank areas. Each second blank area is respectively arranged corresponding to each first blank area. The second coating areas and the second blank areas are alternately arranged along the length direction of the second electrode. A second active material layer is provided on the second coating area. as well as A diaphragm, wherein the diaphragm is separated between the first electrode and the second electrode; The first electrode, the diaphragm, and the second electrode are sequentially stacked and wound to form multiple stacked energy storage units. The first blank area and the second blank area are both located at the winding points of two adjacent energy storage units. In this configuration, one of the first electrode and the second electrode is a positive electrode, and the other is a negative electrode.

2. The battery cell according to claim 1, characterized in that, Both the first electrode and the second electrode have a beginning end and an end end along the length direction of the first electrode; Along the length of the first electrode, the width of the first blank area and the width of the second blank area both gradually increase from the beginning to the end.

3. The battery cell according to claim 2, characterized in that, Along the length of the first electrode, the width of each first blank area is equal to the width of the corresponding second blank area; The width of the first blank area satisfies: W=π*(A+(n-1)*(B+C+2D)) / 2, where A is the thickness of the winding needle, B is the thickness of the first electrode, C is the thickness of the second electrode, D is the thickness of the diaphragm, and n is the number of winding layers.

4. The battery cell according to any one of claims 1-3, characterized in that, When the first electrode is a positive electrode, the width of the second coating area is greater than the width of the first coating area along the length direction.

5. The battery cell according to any one of claims 1-3, characterized in that, The first electrode has two opposing surfaces, and each of the two surfaces of the first electrode has a plurality of the first coated areas and a plurality of the first blank areas; And / or, The second electrode has two opposing surfaces, and each of the two surfaces of the second electrode is provided with a plurality of second coating areas and a plurality of second blank areas.

6. The battery cell according to claim 5, characterized in that, When the first electrode has a start end and an end end along its length, and both surfaces of the first electrode have the first coating area and the first blank area, the first coating area closest to the end on one of the surfaces is not provided with the first active material layer.

7. The battery cell according to any one of claims 1-3, characterized in that, The first electrode sheet is provided with a plurality of first electrode tabs, and the second electrode sheet is provided with a plurality of second electrode tabs. The plurality of first electrode tabs after being wound are stacked on top of each other, and the plurality of second electrode tabs after being wound are stacked on top of each other.

8. A lithium battery, characterized in that, The lithium battery includes a housing and a cell as described in any one of claims 1-7, wherein the cell is disposed within the housing.

9. An electrical appliance, characterized in that, Including the lithium battery as described in claim 8.

10. A method for manufacturing a battery cell, characterized in that, Includes the following steps: A first electrode is provided, which is a long strip. The first electrode has multiple first coated areas and multiple first blank areas. The first coated areas and the first blank areas are alternately arranged along the length direction of the first electrode. A first active material layer is provided on the first coated area. A second electrode is provided, which is a long strip. The second electrode has multiple second coating areas and multiple second blank areas. Each second blank area is respectively disposed corresponding to each first blank area. The second coating areas and the second blank areas are alternately disposed along the length direction of the second electrode. A second active material layer is disposed on the second coating area. A diaphragm is provided to separate the first electrode and the second electrode; The first electrode, the diaphragm, and the second electrode are stacked in sequence and then wound using a winding needle to form a battery cell. In this configuration, one of the first electrode and the second electrode is a positive electrode, and the other is a negative electrode.

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