Electrode plates, electrode assemblies, battery cells, batteries and power consumption devices

Abstract

The present invention relates to an electrode plate (30), an electrode assembly (22), a battery cell (20), a battery (10), a power consumption device, and a method for manufacturing the electrode assembly (22). The electrode plate (30) includes a laminated segment (31) and a bendable segment (32) connected to the laminated segment (31) for bending, wherein a reinforcing structure (33) is installed in the region of the laminated segment (31) close to the bendable segment (32).

Description

Technical Field

[0001] This application relates to the field of battery technology, and particularly to a plate, an electrode assembly, a battery cell, a battery, an electrical consumer device, and a method for manufacturing an electrode assembly.

Background Art

[0002] As battery technology continues to progress, various new energy industries that use batteries as energy storage devices are developing rapidly. In order to improve the energy density of battery cells, currently, the thickness of the plates of battery cells is generally designed to be relatively thin. However, when such plates are bent, misalignment is likely to occur, which further affects the processing yield of the electrode assembly, the performance of this electrode assembly, and may even cause safety accidents.

Summary of the Invention

Problems to be Solved by the Invention

[0003] Embodiments of this application provide a plate, an electrode assembly, a battery cell, a battery, an electrical consumer device, and a method for manufacturing an electrode assembly, which can improve the processing efficiency of the electrode assembly.

Means for Solving the Problems

[0004] According to a first aspect, a plate is provided, which includes a laminated segment and a bending segment connected to the laminated segment for bending, wherein a reinforcing structure is installed in a region of the laminated segment close to the bending segment.

[0005] Therefore, in the embodiment of this application, the strength of the region of the laminated segment close to the bent segment can be increased by installing a reinforcing structure in the region of the laminated segment close to the bent segment. Because the strength of the region of the laminated segment close to the bent segment is relatively large, the position of the bent segment can be determined by the reinforcing structure, and in the process of bending the electrode plate to form the electrode assembly, the bending position of the electrode plate can be restricted, the electrode plate can be bent at the bent segment, the misalignment of the bending position of the electrode plate can be reduced, wrinkles in the region of the laminated segment close to the bent segment can be reduced, the processing accuracy of the electrode assembly can be improved, and the processing yield and performance of the electrode assembly can be further improved. For example, lithium deposition phenomena due to misalignment or wrinkles of the electrode plate can be reduced, and the reliability of the electrode assembly can be further improved.

[0006] In some embodiments, this reinforcing structure includes protruding structures that project from the surface of the laminated segment. This reinforcing structure is realized by the installed protruding structures, resulting in a simple and easy-to-implement structure. Furthermore, the method of forming these protruding structures can be flexibly configured according to the actual application, and they are easy to manufacture.

[0007] In some embodiments, the range of the ratio of the projection height of this projection structure to the thickness of this laminated segment is [0.3, 50], selectively [5, 40], and preferably [8, 20].

[0008] Considering the requirements for energy density and performance within the battery cell, the range of thickness values ​​for the laminated segment is limited. If the ratio of the protrusion height to the thickness of the laminated segment is set too small, the protrusion height will be too small, and therefore the strength increased by this protrusion structure will also be too small. The difference in strength between this reinforcing structure and the strength of other areas of the laminated segment will be very small, making it highly likely that the limiting and positioning effects of the bending segment will not be achieved. Conversely, if the ratio of the protrusion height to the thickness of the laminated segment is set too large, the protrusion height will be too large, increasing the distance between the multilayer plates after processing the electrode plate into an electrode assembly, further reducing the space utilization rate of the electrode assembly within the battery cell, and reducing the energy density of the battery cell. On the other hand, if the protrusion structure is formed by a press method, the height of the pressed protrusion structure will be too high, making the electrode plate more susceptible to damage or fracture at the pressing point, further affecting the processing efficiency and yield of the electrode plate and electrode assembly.

[0009] In some embodiments, the projection structure protrudes from the first surface of the laminated segment, recesses from the second surface of the laminated segment, and the first surface is positioned opposite the second surface. Such projection structures are easy to manufacture and implement, do not require additional structures, and do not significantly increase the weight of the electrode plates.

[0010] In some embodiments, this protruding structure includes a reinforcing sheet placed on the surface of the laminated segment, and by selecting an appropriate material and processing this reinforcing sheet according to the actual demand, a reinforcing structure of a corresponding specific strength can be obtained, making the implementation method more flexible and effective.

[0011] In some embodiments, the range of the ratio of the stiffness of this reinforcing structure to the stiffness of other areas of the laminated segment is [1.5,65], selectively [2,40], and preferably [10,25]. If the ratio of the stiffness of the reinforcing structure to the stiffness of other areas of the laminated segment is too small, the stiffness of the reinforcing structure is greater than the stiffness of other areas of the laminated segment, resulting in a very small difference between the strength of this reinforcing structure and the strength of other areas of the laminated segment, and the reinforcing structure is unlikely to achieve the desired effect of restricting and positioning the bending segment. Conversely, if the ratio of the stiffness of this reinforcing structure to the stiffness of other areas of the laminated segment is too large, the strength requirements for this reinforcing structure become too high due to the structural and material limitations of the laminated segment itself, increasing the difficulty of processing and material selection, and raising costs.

[0012] In some embodiments, the stiffness range of this reinforcing structure is [10 N / m, 300 N / m], preferably [50 N / m, 150 N / m]. Since the stiffness of the reinforcing structure must be greater than the stiffness of other areas of the laminated segment, the stiffness value of this reinforcing structure should not be too small so that it can exert its effect of limiting and positioning the bending segment. Conversely, if the stiffness of this reinforcing structure is set too high, the strength requirements for this reinforcing structure will be too high, making the processing and material selection of this reinforcing structure more difficult and costly.

[0013] In some embodiments, the reinforcing structure does not pass through the longitudinal centerline of the electrode plate of the laminated segment, and the ratio of the span of the reinforcing structure along the longitudinal direction of the electrode plate to the length of the laminated segment is in the range of [10%, 50%]. Because the reinforcing structure does not pass through the longitudinal centerline of the electrode plate of the laminated segment, the ratio of the span of the reinforcing structure along the longitudinal direction of the electrode plate to the length of the laminated segment is less than 50%. Conversely, the ratio of the span of the reinforcing structure along the longitudinal direction of the electrode plate to the length of the laminated segment should not be too small, as the span of the reinforcing structure should be sufficiently large to improve its reinforcing effect.

[0014] In some embodiments, the ratio of the span along the longitudinal direction of this electrode plate of the reinforcing structure to the length of this laminated segment is in the range of [10%, 100%]. This ratio should not be too small; for example, generally setting this ratio to 10% or more ensures that the span of the reinforcing structure is sufficiently large, thereby improving the reinforcing effect of the reinforcing structure.

[0015] In some embodiments, the range of the ratio of the sum of the widths of all the reinforcing structures aligned along the width direction of the electrode plate to the width of the electrode plate is [1 / 3, 0.8], preferably [0.4, 0.6]. If this ratio is set too small, the reinforcing structures will not be installed in most areas along the width direction of the electrode plate, making misalignment more likely in these areas when the electrode plate is bent, which may further affect the processing yield of the electrode assembly and the usability of the electrode assembly. Conversely, if this ratio is set too large, the area occupied by the reinforcing structures will be too large, which may affect the strength of these areas. In particular, when the reinforcing structures are installed by a press method, if the reinforcing structures are too distributed along the width direction of the electrode plate, the effect of reinforcing the structural strength of areas close to the bent segments of the laminated segments may not be obtained, and misalignment may still occur when the electrode plate is bent, which may further affect the processing yield of the electrode assembly and the usability of the electrode assembly.

[0016] In some embodiments, the range of the ratio between the shortest length between the end of the reinforcing structure closest to the bent segment and the centerline of the bent segment and the thickness of the electrode plate is [0.016, 0.5], preferably [0.05, 0.4]. If this ratio is too small, the reinforcing structure is too close to the centerline of the bent segment, as the electrode plate is generally relatively thin. This results in a small limit on the range of the bent segment that the reinforcing structure restricts when the electrode plate is bent, making it difficult to bend the electrode plate and increasing the difficulty of processing the electrode assembly. Conversely, if this ratio is too large, the reinforcing structure is too far from the centerline of the bent segment. This makes it difficult for the reinforcing structure to restrict the bent segment, and misalignment is still likely to occur when the electrode plate is bent, further affecting the processing efficiency and yield of the electrode assembly.

[0017] In some embodiments, the reinforcing structure is installed at an inclination with respect to the width direction of the electrode plate, so that the reinforcing structure has a reinforcing effect in the width direction perpendicular to the electrode plate, thereby limiting the bending position of the electrode plate.

[0018] In some embodiments, the angle between the reinforcing structure and the plate in the width direction is in the range of [45°, 135°]. If this angle is set to be too large or too small, the reinforcing effect of the reinforcing structure in the width direction perpendicular to the plate is much smaller than that in the width direction parallel to the plate, reducing the buckling prevention and displacement prevention effect of the reinforcing structure.

[0019] In some embodiments, multiple reinforcing structures are installed in the region of the laminated segment near this bent segment, aligned along the width direction of the electrode plate, thereby increasing the structural strength of different regions in the width direction of the electrode plate, and preventing the electrode plate from bending. segment This reduces the possibility of localized misalignment occurring when the material is folded along a curve.

[0020] In some embodiments, multiple reinforcing structures are arranged at equal intervals along the width direction of the electrode plate, making them easy to process and allowing for a more uniform arrangement of these reinforcing structures, thereby uniformly increasing the structural strength of different regions in the width direction of the electrode plate.

[0021] In some embodiments, multiple of these reinforcing structures protrude from the surface of the laminated segment, and their protrusion directions coincide. By setting the protrusion directions of multiple reinforcing structures aligned along the width direction of the electrode plate to coincide, these reinforcing structures can occupy the space on the same side of the electrode plate, reducing the gaps between the multilayer structures of the electrode assembly, further improving the space utilization rate of the electrode assembly within the battery cell, and thereby improving the energy density of the battery cell.

[0022] In some embodiments, the electrode plate includes a plurality of laminated segments, and the bent segment is connected to a first and a second laminated segment of the plurality of laminated segments, with the reinforcing structure installed in the region of the first laminated segment close to the bent segment and the region of the second laminated segment close to the bent segment, respectively. Then, the region between the reinforcing structure of the first laminated segment and the reinforcing structure of the second laminated segment includes the bent segment, that is, the position of the bent segment is restricted by both the reinforcing structure of the first laminated segment and the reinforcing structure of the second laminated segment, thereby reducing misalignment, bending, and wrinkling of the first and second laminated segments when the electrode plate is bent, allowing for more accurate positioning of the bent segment, improving the processing efficiency and yield of the electrode assembly, and further improving the performance of the battery cell.

[0023] In some embodiments, the positions of the reinforcing structure of the first laminated segment and the reinforcing structure of the second laminated segment in the width direction of the electrode plate are set correspondingly, and / or the positions of the reinforcing structure of the first laminated segment and the reinforcing structure of the second laminated segment in the width direction of the electrode plate are set offset from each other.

[0024] While the positions of the reinforcing structures of the first laminated segment and the second laminated segment in the width direction of the electrode plate are installed corresponding to each other, when the electrode plate is bent along the bending segment, the reinforcing structures of the first laminated segment and the second laminated segment can basically overlap, with a simple structure and easy processing. While the reinforcing structures of the first laminated segment and the second laminated segment are installed offset from each other, when the electrode plate is bent along the bending segment, the reinforcing structures of the first laminated segment and the second laminated segment cannot completely overlap. Thus, the position installation of the reinforcing structure of the first laminated segment and the reinforcing structure of the second laminated segment becomes more flexible. When this electrode plate is bent to form an electrode assembly, the space occupied by the reinforcing structure of the first laminated segment and the reinforcing structure of the second laminated segment is adjusted, the space between different electrode plates is rationally utilized, the space utilization rate inside the battery cell of this electrode assembly is improved, and furthermore, the energy density of this battery cell can be improved.

[0025] In some embodiments, the reinforcing structure of the first laminated segment and the reinforcing structure of the second laminated segment are arranged at equal intervals in the width direction of the electrode plate. In this way, the uniform arrangement of the reinforcing structure of the first laminated segment and the reinforcing structure of the second laminated segment is easy to process, and the reinforcing structure is uniformly distributed, reducing the risk of displacement occurring in different regions of the first laminated segment and the second laminated segment when the electrode plate is bent, and improving the processing efficiency and processing yield of the electrode assembly.

[0026] In some embodiments, the reinforcement structure of this first laminated segment includes a protrusion structure protruding from the surface of this first laminated segment, the reinforcement structure of this second laminated segment includes a protrusion structure protruding from the surface of this second laminated segment, and the protruding direction of the reinforcement structure of this first laminated segment is opposite to the protruding direction of the reinforcement structure of this second laminated segment. Thus, after the electrode plate is bent along the bending segment, the first laminated segment and the second laminated segment are laminated and installed, and when the protruding direction of the reinforcement structure of the first laminated segment coincides with the protruding direction of the reinforcement structure of the second laminated segment, the reinforcement structure of the second laminated segment protrudes from the surface on one side of this second Stacked segments and is recessed from the surface on the other side of this second laminated segment, the portion of the reinforcement structure of the first laminated segment protruding from the surface of this first laminated segment can be accommodated in the recessed area of the reinforcement structure of the second laminated segment, and further the gap between different electrode plates can be reduced, the space utilization rate inside the battery cell of this electrode assembly can be improved, and further the energy density of the battery cell can be improved.

[0027] In some embodiments, a cut extending along the width direction of this electrode plate is provided in this bending segment. The provided cut can realize the positioning of the bending segment, reduce the offset at the bending location of the electrode plate, and further reduce the offset between different electrode plates of the electrode assembly. On the other hand, this cut can reduce the bending difficulty, reduce the resistance during bending, and further improve the processing efficiency of the electrode assembly.

[0028] In some embodiments, the number of these notches includes multiple notches, and the reinforcing structure engages with the multiple notches by corresponding to the connection area between two adjacent notches among the multiple notches, thereby jointly positioning and restricting the position of the bent segment, improving the structural strength in the area surrounding the bent segment of the electrode plate, and minimizing the occurrence of misalignment or wrinkles in different areas along the width direction of the electrode plate when the electrode plate is bent, thereby improving the processing efficiency and yield of the electrode assembly.

[0029] In some embodiments, the number of these notches includes a plurality of notches, each including edge notches located at both ends of the electrode plate along the width direction of the electrode plate and intermediate notches located in the intermediate region of the electrode plate, wherein the length of the edge notches along the width direction of the electrode plate is greater than the length of the intermediate notches along the width direction of the electrode plate.

[0030] When the bending segment of the electrode plate is folded, the resistance at both end edge positions along the width direction of the electrode plate is greater than the resistance at the intermediate position, and the variation in the fold at the electrode plate edge position is also greater. Therefore, by setting the length along the width direction of the edge cut to be greater than the length along the width direction of the intermediate cut, the resistance at the edge position of the electrode plate can be reduced more significantly, the variation can be reduced, and the probability of offset when the electrode plate is folded can be reduced, thereby reducing the possibility of active material deposition or electrode assembly failure, and improving the processing efficiency and yield of the electrode assembly.

[0031] In some embodiments, the number of these cuts includes multiple cuts, and the lengths of these multiple cuts are equal along the width direction of the electrode plate. By setting the size of the multiple cuts aligned along the width direction to be equal, the number of times the size of these cuts needs to be adjusted can be reduced, lowering the difficulty of processing and improving processing efficiency.

[0032] In some embodiments, the notch is located in the center of the bending segment along the longitudinal direction of the electrode plate, which allows for more precise positioning when the electrode plate is bent along the notch in which it is installed, minimizing misalignment and offset of the electrode plate and improving the processing efficiency and yield of the electrode assembly.

[0033] In some embodiments, this electrode plate is a negative electrode plate without a negative electrode. This electrode plate is thinner, and when assembled into an electrode assembly and placed within a battery cell, it improves the space utilization rate of the electrode assembly and further increases the energy density of the battery cell. Furthermore, because this electrode plate is thinner, it is more prone to misalignment or wrinkling when bent. The installed reinforcing structure effectively reduces misalignment and wrinkling, improving the processing efficiency and yield of the electrode assembly.

[0034] According to a second embodiment, an electrode assembly is provided, the electrode assembly comprising a first electrode plate, the first electrode plate being the electrode plate described in the first embodiment, and the first electrode plate being configured to be bent at this bending segment.

[0035] In some embodiments, this reinforcing structure is an indentation on the surface of the laminated segment. This reinforcing structure is the first pole plate During the bending process, it may be used to restrict the position of the bending segment, and thereafter this reinforcing structure is an indentation on the surface of the laminated segment, and can improve the space utilization rate of the electrode assembly within the battery cell without occupying the gaps between different electrode plate layers of the electrode assembly, and further improve the energy density of the battery cell.

[0036] In some embodiments, the electrode assembly further includes a plurality of second electrodes with opposite polarity to the first electrode, and these plurality of second electrodes and plurality of this laminated segments are arranged in an alternating stack along the thickness direction of the laminated segments. In this way, it is not necessary to bend the second electrodes during the bending process of the electrode assembly, reducing the number of layers to be bent and lowering the difficulty of bending the electrode assembly.

[0037] In some embodiments, the first electrode plate includes multiple bent segments, where the bending directions of the two bent segments at both ends of the same laminated segment are opposite. By bending in different directions, a laminated electrode assembly is formed, and this structure is simple and easy to implement.

[0038] According to a third aspect, a battery cell is provided, which includes the electrode assembly described in the second aspect.

[0039] According to a fourth aspect, a battery is provided, the battery comprising a plurality of battery cells, the battery cells comprising the electrode assembly described in the second aspect.

[0040] According to the fifth aspect, a power-consuming device is provided, which includes a battery cell as described in the third aspect or a battery as described in the fourth aspect, and the battery cell or the battery is used to provide electrical energy to the power-consuming device.

[0041] In some embodiments, the power-consuming device is a vehicle, a ship, or an aerospace aircraft.

[0042] According to a sixth aspect, a method for manufacturing an electrode assembly is provided, the method comprising providing a first electrode plate including a laminated segment and a bent segment, the bent segment being connected to the laminated segment, a reinforcing structure being provided in the region of the laminated segment close to the bent segment, and bending the first electrode plate at the bent segment.

[0043] Therefore, in the method for manufacturing an electrode assembly according to the embodiment of this application, in the process of forming an electrode assembly by bending the first electrode plate, the bending position of the first electrode plate is limited by a reinforcing structure installed on the first electrode plate, so that the first electrode plate is bent at the bending segment, the bending position misalignment of the first electrode plate can be reduced, wrinkles in the area of ​​the laminated segment close to the bending segment can be reduced, the processing accuracy of the electrode assembly can be improved, and the processing yield and performance of the electrode assembly can be further improved. For example, lithium deposition phenomena due to misalignment or wrinkles of the first electrode plate can be reduced, and the reliability of the electrode assembly can be further improved.

[0044] In some embodiments, the method includes forming a protruding structure on the surface of the laminated segment by pressing the laminated segment along its thickness direction, and the reinforcing structure includes this protruding structure and presses the laminated segment. The reinforcing structure formed by the pressing method limits the bending position of the first electrode when the first electrode is bent, so that the first electrode is bent at the bending segment, reducing the bending misalignment of the first electrode and reducing wrinkles in the area of ​​the laminated segment close to the bending segment. With respect to the formed electrode assembly, the size of the reinforcing structure that protrudes from other areas of the laminated segment after pressing is reduced, and thus it can be made almost flush with other areas of the laminated segment, further reducing the distance between the first electrode and the second electrode, further reducing the ion conduction path and improving the performance of the electrode assembly.

[0045] In some embodiments, pressing the laminated segment involves pressing it using a hot-pressing method. Due to the hot-pressing process, the originally protruding reinforcing structure is crushed, that is, the size of the reinforcing structure that protrudes from other areas of the laminated segment is reduced, and thus it can be made nearly flush with other areas of the laminated segment. Furthermore, the distance between the first electrode plate and the second electrode plate can be further reduced through the hot-pressing process, further reducing the ion conduction path, improving the space utilization rate of the electrode assembly inside the battery cell, and further improving the energy density of the battery cell. [Brief explanation of the drawing]

[0046] [Figure 1] This is a schematic diagram of the structure of a vehicle disclosed in one embodiment of this application. [Figure 2] This is a schematic diagram of the disassembled structure of a battery disclosed in one embodiment of this application. [Figure 3] This is a schematic diagram of the structure of multiple battery cells included in one embodiment of the battery disclosed in this application. [Figure 4] This is a schematic diagram of the structure of a battery cell disclosed in one embodiment of this application. [Figure 5] This is a schematic diagram of the exploded structure of a battery cell disclosed in one embodiment of this application. [Figure 6] This is a schematic diagram of the structure of the first electrode plate disclosed in one embodiment of this application. [Figure 7] This is an enlarged local structure view of the first electrode plate disclosed in one embodiment of this application. [Figure 8] This is a schematic local cross-sectional view of the first electrode plate disclosed in one embodiment of this application. [Figure 9] This is a schematic local cross-sectional view of another first electrode plate disclosed in one embodiment of this application. [Figure 10] This is a schematic diagram of the structure of the first electrode plate disclosed in another embodiment of this application. [Figure 11] This is a schematic diagram of the structure of the first electrode plate disclosed in yet another embodiment of this application. [Figure 12]This is a schematic diagram of the structure of the first electrode plate disclosed in yet another embodiment of this application. [Figure 13] This is a magnified view of the local structure of the first electrode plate disclosed in yet another embodiment of this application. [Figure 14] This is a schematic diagram of the local structure of the first electrode plate disclosed in yet another embodiment of this application. [Figure 15] This is a schematic diagram of the structure of an electrode assembly disclosed in one embodiment of this application. [Figure 16] This is a schematic side view of an electrode assembly disclosed in one embodiment of this application. [Figure 17] This is a schematic diagram of the structure of another electrode assembly disclosed in one embodiment of this application. [Figure 18] This is a schematic side view of another electrode assembly disclosed in one embodiment of this application. [Figure 19] This is a schematic flowchart of a method for manufacturing an electrode assembly disclosed in one embodiment of this application. In the drawings, the drawings are not drawn to actual scale. [Modes for carrying out the invention]

[0047] The embodiments of this application will be described in more detail below, linking them with the drawings and examples. The detailed descriptions of the embodiments and drawings below are for illustrative purposes to illustrate the principles of this application, but are not intended to limit the scope of this application; in other words, this application is not limited to the embodiments described.

[0048] In the description of this application, unless otherwise specified, the meaning of "multiple" is two or more. The directions or positional relationships indicated by terms such as "up," "down," "left," "right," "inside," and "outside" are merely for the convenience and simplification of the description in this application and do not indicate or imply that the mentioned devices or elements have a specific direction or must be configured and operated in a specific direction, and should not be understood as limitations on this application. Furthermore, terms such as "first," "second," and "third" are used solely for descriptive purposes and should not be understood as indicating or implying relative importance. "Perpendicular" does not mean strictly perpendicular, but within an acceptable margin of error. "Parallel" does not mean strictly parallel, but within an acceptable margin of error.

[0049] The directional terms appearing in the following description all refer to the directions shown in the figures and do not limit the specific structure of this application. It should be further explained that, unless otherwise explicitly stated or limited, the terms “attachment,” “connection,” and “connection” should be understood in a broad sense, and may include, for example, a fixed connection, a removable connection, or an integral connection; a direct connection or an indirect connection via an intermediate medium. Those skilled in the art will be able to understand the specific meaning of these terms in this application depending on the specific circumstances.

[0050] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the dimensions such as thickness, length, and width of various components in the embodiments of this application shown in the drawings, and the overall dimensions such as thickness, length, and width of the integrating apparatus, are illustrative and should not constitute any limitation to this application.

[0051] In the embodiments of this application, the battery cell may be a secondary battery, which is a battery cell that can continue to be used by activating the active material by charging after the battery cell has been discharged.

[0052] The battery cell may be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited thereto.

[0053] In some implementations, the battery cell in the embodiments of this application may be a metal battery, and specifically, this metal battery may include lithium metal secondary batteries, sodium metal batteries, or magnesium metal batteries, and the embodiments of this application are not limited to these.

[0054] A battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator member. During charging and discharging of the battery cell, active ions (e.g., lithium ions) move back and forth between the positive and negative electrodes, undergoing intercalation and deintercalation. The separator member is placed between the positive and negative electrodes and can prevent short circuits between them while allowing active ions to pass through.

[0055] In some embodiments, the positive electrode may be a positive electrode plate, which may include a positive electrode current collector and a positive electrode active material placed on at least one surface of the positive electrode current collector.

[0056] For example, a positive electrode current collector has two opposing surfaces in the direction of its own thickness, and the positive electrode active material is placed on one or both of the two opposing surfaces of the positive electrode current collector.

[0057] For example, the positive electrode current collector may be a metal foil sheet or a composite current collector. For example, as the metal foil sheet, silver-surface-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium can be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may be formed by forming a metal material (such as aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy) on a polymer material substrate (for example, a substrate such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, or polyethylene).

[0058] For example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphate, lithium transition metal oxide, and their respective reformed compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used individually or in combination of two or more. Here, examples of lithium-containing phosphates may include, but are not limited to, at least one of the following: lithium iron phosphate (e.g., LiFePO4 (which may be abbreviated as LFP)), composite materials of lithium iron phosphate and carbon, lithium manganese phosphate (e.g., LiMnPO4), composite materials of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and composite materials of lithium iron manganese phosphate and carbon.

[0059] In some embodiments, ,example The positive electrode active material may include at least one of a sodium transition metal oxide, a polyanionic compound, and a Prussian blue compound.

[0060] In some examples, the chemical formula of sodium transition metal oxide is Na x MO2 can be satisfied, where M includes one or more of Ti, V, Mn, Co, Ni, Fe, Zn, V, Zr, Ce, Cr, and Cu, 0 <x≦1である。

[0061] For example, Na x In MO2, x may be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1.

[0062] In some embodiments, the sodium transition metal oxide may be a doped and modified sodium transition metal oxide, and the doping modification of the sodium transition metal oxide may include at least one of sodium site doping modification, oxygen site doping modification, transition metal site doping modification, and surface coating modification.

[0063] In some embodiments, the positive electrode can be made of foamed metal. The foamed metal may be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon. When foamed metal is used as the positive electrode, the positive electrode active material may or may not be provided on the surface of the foamed metal. For example, the foamed metal may be filled with and / or deposited with a lithium source material, potassium metal, or sodium metal, and the lithium source material may be lithium metal and / or a lithium-rich material.

[0064] In some embodiments, the negative electrode may be a negative electrode plate, and the negative electrode plate may include a negative electrode current collector.

[0065] For example, the negative electrode current collector can be a metal foil sheet, foamed metal, or a composite current collector. For example, as the metal foil sheet, silver-surface-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium can be used. The composite current collector may include a polymer material base layer and a metal layer. The foamed metal may be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (for example, a substrate such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, or polyethylene).

[0066] In some implementations, the battery cell in the embodiment of this application may be a sodium secondary battery without a negative electrode.

[0067] A sodium secondary battery without a negative electrode is a battery constructed without a negative electrode active material layer being spontaneously formed on the negative electrode side during the battery manufacturing process. For example, the negative electrode active material layer is formed without the installation of a sodium metal or carbonaceous active material layer on the negative electrode through processes such as coating or deposition during the battery manufacturing process. During the initial charge, sodium ions gain electrons on the anode side, and metallic sodium deposits a sodium metallic phase on the current collector surface. During discharge, the metallic sodium transforms into sodium ions and returns to the positive electrode, enabling cyclic charging and discharging. Compared to other sodium secondary batteries, a sodium secondary battery without a negative electrode can achieve a higher energy density because it lacks a negative electrode active material layer.

[0068] In some implementations, to improve battery performance, the negative electrode side of a sodium secondary battery without a negative electrode is provided with several functional coatings, such as carbonaceous materials, metal oxides, or alloys, to improve the conductivity of the negative electrode current collector and enhance the uniformity of the deposited sodium metal.

[0069] In some implementation methods, the CB value of a sodium secondary battery without a negative electrode is 0.1 or less.

[0070] Specifically, the CB value is the capacity per unit area of ​​the negative electrode plate in a secondary battery divided by the capacity per unit area of ​​the positive electrode plate. Batteries without a negative electrode do not contain functional coatings, or only contain small amounts of functional coatings, so the capacity per unit area of ​​the negative electrode plate is relatively small, and the CB value of such secondary batteries is 0.1 or less.

[0071] In some embodiments, the negative electrode plate may further include a negative electrode current collector and a negative electrode active material placed on at least one surface of the negative electrode current collector.

[0072] For example, the negative electrode current collector has two opposing surfaces in the thickness direction of itself, and the negative electrode active material is placed on one or both of the two opposing surfaces of the negative electrode current collector.

[0073] For example, the negative electrode active material can be a negative electrode active material known in the art for use in battery cells. For example, the negative electrode active material may include at least one material from among artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate.

[0074] In some embodiments, the negative electrode can be made of foamed metal. The foamed metal may be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon. When foamed metal is used as the negative electrode plate, the negative electrode active material does not need to be provided on the surface of the foamed metal, although it may, of course, be provided.

[0075] For example, the negative electrode current collector may be further filled with and / or deposited with a lithium source material, potassium metal, or sodium metal, the lithium source material being lithium metal and / or lithium-rich material.

[0076] In some embodiments, the material of the positive electrode current collector may be aluminum, and the material of the negative electrode current collector may be copper.

[0077] In some embodiments, the electrode assembly further includes a separator member placed between the positive and negative electrodes.

[0078] In some embodiments, the separator member is a separator. This application does not particularly limit the type of separator, and any known porous separator having good chemical and mechanical stability may be selected.

[0079] For example, the main material of the separator may be selected from at least one of the following: glass fiber, nonwoven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramics.

[0080] In some embodiments, the separator component is a solid electrolyte. The solid electrolyte is placed between the positive and negative electrodes and serves to facilitate ion transmission and isolate the positive and negative electrodes.

[0081] In some embodiments, the battery cell further includes an electrolyte that plays a role in conducting ions between the positive and negative electrodes. This application does not specifically limit the type of electrolyte, which can be selected according to the requirements. The electrolyte may be liquid, gel-like, or solid.

[0082] In some embodiments, the electrode assembly is a wound structure. The positive electrode plate and the negative electrode plate are wound into the wound structure.

[0083] In some embodiments, the electrode assembly has a layered structure.

[0084] For example, multiple positive and negative electrodes may be provided, and the multiple positive and negative electrodes may be stacked alternately.

[0085] For example, there may be multiple positive electrode plates, and the negative electrode plates may be folded and stacked to form multiple folded segments, with one positive electrode plate sandwiched between adjacent folded segments.

[0086] For example, both the positive and negative plates are folded and stacked to form multiple folded segments.

[0087] For example, multiple separator members may be provided, each installed between either an adjacent positive or negative electrode plate.

[0088] For example, separator members can be installed continuously, folded or wound, between adjacent positive or negative plates.

[0089] In some embodiments, the shape of the electrode assembly may be cylindrical, flattened, or polygonal prism-shaped.

[0090] In some embodiments, the electrode assembly is provided with tabs from which current can be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0091] In some embodiments, the battery cell may include a housing. The housing is used to package components such as electrode assemblies and electrolytes. The housing may be a steel case, an aluminum case, a plastic case (e.g., polypropylene), a composite metal case (e.g., a copper-aluminum composite housing), or an aluminum film. The housing includes a case and a cover plate.

[0092] For example, the battery cell may be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shape. A prismatic battery cell may consist of a prismatic housing battery cell, a blade-shaped battery cell, and a polygonal prism. battery cell and include, polygonal prism battery cell For example, a hexagon battery cell And so on, and this application is not particularly limited.

[0093] The battery referred to in the embodiments of this application is a single physical module which may include one or more battery cells to provide higher voltage and capacity. If there are multiple battery cells, the multiple battery cells are connected in series, in parallel, or in series-parallel via busbar members.

[0094] In some embodiments, the battery may be a battery module, and if there are multiple battery cells, the multiple battery cells are fixed side by side to form a battery module.

[0095] In some embodiments, the battery may be a battery pack, which includes a housing and battery cells, and the battery cells or battery modules are housed in the housing.

[0096] In some embodiments, the housing can be part of the vehicle's chassis structure. For example, a portion of the housing may be at least part of the vehicle's floor, or a portion of the vehicle's cross members and side members.

[0097] An electrode assembly is installed inside the battery cell in the embodiment of this application. In the process of forming the electrode assembly by laminating or winding the electrode plates, it may be necessary to bend the electrode plates. However, since the electrode plates are generally very thin, it is difficult to precisely control the specific bending area of ​​the electrode plate. In such cases, the bending portion of the electrode plate may not be bent to the predetermined size, and furthermore, a phenomenon of displacement of the electrode plate, such as misalignment or wrinkling of the electrode plate, may occur. This affects the processing yield of the electrode assembly and the performance of the electrode assembly. For example, this can lead to an increased likelihood of lithium deposition on the electrode plate, and may even cause safety accidents.

[0098] Therefore, embodiments of this application provide electrode plates, electrode assemblies, battery cells, batteries, power consumption devices, and methods for manufacturing electrode assemblies, thereby solving the above problems. The electrode plate of the embodiments of this application includes connected laminated segments and bent segments, the bent segments being used for bending, i.e., the electrode plate can be bent at these bent segments. Reinforcement structures are installed in the region of the laminated segments close to the bent segments, thereby increasing the strength of this region of the laminated segments close to the bent segments. Because the strength of this region of the laminated segments close to the bent segments is relatively high, the position of the bent segments can be determined by the reinforcement structures, and by limiting the bending position of the electrode plate during the process of bending the electrode plate to form the electrode assembly, the electrode plate can be bent at the bent segments, reducing misalignment of the bent positions of the electrode plate, reducing wrinkles in the region of the laminated segments close to the bent segments, improving the processing accuracy of the electrode assembly, and further improving the processing yield and performance of the electrode assembly. For example, lithium deposition phenomena due to misalignment or wrinkles of the electrode plate can be reduced, further improving the reliability of the electrode assembly.

[0099] The technical solutions described in the embodiments of this application are all applicable to power-consuming devices that use various types of batteries.

[0100] Power-consuming devices may include vehicles, mobile phones, portable devices, laptop computers, steamships, aerospace vehicles, electric toys, and power tools. Vehicles may be fuel-oil vehicles, gas vehicles, or new energy vehicles, and new energy vehicles may be pure electric vehicles, hybrid vehicles, or range-extender vehicles. Aerospace vehicles include airplanes, rockets, space shuttles, and spacecraft. Electric toys include stationary or mobile electric toys, such as game consoles, electric vehicle toys, electric steamship toys, and electric airplane toys. Power tools include metal cutting power tools, polishing power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, hammer drills, concrete vibrators, and electric planers. The embodiments of this application do not particularly limit the power-consuming devices described above.

[0101] In the following embodiments, for the sake of explanation, we will use a vehicle as an example of the power-consuming device.

[0102] For example, as shown in Figure 1, this is a schematic diagram of the structure of a vehicle 1 according to one embodiment of the present application. The vehicle 1 may be a fuel oil vehicle, a gas vehicle, or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle, or a range extender vehicle. A motor 60, a controller 50, and a battery 10 may be installed inside the vehicle 1, and the controller 50 is used to control the power supply of the motor 60 by the battery 10. For example, the battery 10 may be installed at the bottom, front, or rear of the vehicle 1. The battery 10 may be used to power the vehicle 1, for example, as an operating power source for the vehicle 1, used in the circuit system of the vehicle 1, for example, for starting the vehicle 1, navigation, and the operating power consumption demand during operation. In another embodiment of the present application, the battery 10 can provide driving power to the vehicle 1 not only as an operating power source for the vehicle 1, but also as a driving power source for the vehicle 1, instead of or in place of fuel oil or natural gas.

[0103] To meet different power consumption demands, a battery may include multiple battery cells, which may be connected in series, in parallel, or in a series-parallel configuration, where series-parallel is a combination of series and parallel connections. The battery may also be called a battery pack. Selectively, multiple battery cells may be connected in series, in parallel, or in a series-parallel configuration to form a battery module, and then multiple battery modules may be connected in series, in parallel, or in a series-parallel configuration to form a battery. In other words, multiple battery cells may directly constitute a battery, or they may constitute a battery module, and then the battery modules may constitute a battery.

[0104] For example, Figure 2 shows a schematic diagram of the structure of a battery 10 according to one embodiment of the present application, and the battery 10 may include a plurality of battery cells 20, and Figure 3 shows a schematic diagram of a plurality of battery cells 20 included in the battery 10. As shown in Figures 2 and 3, the battery 10 may further include a housing 11, the inside of which is hollow, and the plurality of battery cells 20 are housed inside the housing 11. Figure 2 shows a possible implementation of the housing 11 according to an embodiment of the present application, and as shown in Figure 2, the housing 11 may include two parts called a first part 111 and a second part 112, respectively, and the first part 111 and the second part 112 are engaged. The shapes of the first part 111 and the second part 112 can be determined according to the shape of the combination of battery modules 200, and at least one of the first part 111 and the second part 112 has an opening. For example, as shown in Figure 2, both the first part 111 and the second part 112 may be hollow rectangular parallelepipeds, and each may have only one open surface, with the opening of the first part 111 and the opening of the second part 112 facing each other, and the first part 111 and the second part 112 engaging with each other to form a housing 11 having a sealed chamber.

[0105] Also, unlike in Figure 2, for example, the first part 111 and the second part 112 are hollow rectangular parallelepipeds with an opening on only one side, while the other is plate-shaped and covers the opening. For example, taking the case where the second part 112 is a hollow rectangular parallelepiped with an opening on only one side, and the first part 111 is plate-shaped, the first part 111 covers the opening of the second part 112 to form a housing 11 with a sealed chamber, and this chamber may be used to house a plurality of battery cells 20. The plurality of battery cells 20 are connected in parallel, in series, or in series-parallel and then placed in the housing 11 formed after the first part 111 and the second part 112 are engaged.

[0106] Selectively, the battery 10 may further include other structures, which are not described here. For example, as shown in Figures 2 and 3, the battery 10 may further include busbar members 12 for realizing electrical connections between multiple battery cells 20, such as parallel, series, or series-parallel connections. Specifically, the busbar members 12 can realize electrical connections between the battery cells 20 by connecting the electrode terminals 214 of the battery cells 20. Furthermore, the busbar members 12 can be fixed to the electrode terminals 214 of the battery cells 20 by welding. The electrical energy of the multiple battery cells 20 can further be extracted through the housing 11 via a conductive mechanism.

[0107] Depending on the different power demands, the number of battery cells 20 in the battery 10 can be set to any number. Multiple battery cells 20 can be connected in series, parallel, or series-parallel to achieve a relatively large capacity or power. Since each battery 10 may contain a relatively large number of battery cells 20, to facilitate installation, the battery cells 20 can be grouped, and each group of battery cells 20 can be used to form a battery module. The number of battery cells 20 contained in a battery module is not limited and can be set according to demand.

[0108] Figure 4 is a schematic diagram of the structure of a battery cell 20 according to one embodiment of this application, and Figure 5 is a schematic diagram of the locally disassembled structure of a battery cell 20 according to one embodiment of this application. For example, the battery cell 20 shown in Figure 5 may be any one of the battery cells 20 shown in Figures 2 to 4. As shown in Figures 4 and 5, for the sake of explanation, a rectangular battery cell 20 is used as an example. Here, direction Z in the figure represents the height direction of the battery cell 20, direction X in the figure represents the width direction or thickness direction of the battery cell 20, and direction Y in the figure represents the longitudinal direction of the battery cell 20, as well as the height direction Z and width direction of the battery cell 20. X The longitudinal direction Y is perpendicular to each other.

[0109] As shown in Figures 4 and 5, the battery cell 20 of the embodiment of this application may include a housing 21. Specifically, the housing 21 may include a case 211 which is a hollow structure having at least one opening, a cover plate 212 which fits over the opening of the case, and an electrode assembly 22 which is housed inside the housing 21.

[0110] It should be understood that the case 211 in the embodiment of this application is a member for housing the electrode assembly 22, and the case 211 may be a hollow structure with openings at one end or both ends. For example, if the case 211 is a hollow structure with an opening at one end, there may be one cover plate 212, and if the case 211 is a hollow structure with openings at both opposing ends, there may be two cover plates 212, and the two cover plates 212 each fit over the openings at both ends of the case 211.

[0111] Case 211 may have various shapes, such as a cylinder, a rectangular parallelepiped, or other polyhedron. Exemplarily, as shown in Figures 4 and 5, the embodiments of this application primarily describe a case 211 as a rectangular parallelepiped structure with a hollow structure forming an opening at one end.

[0112] It should be understood that the cover plate 212 in the embodiment of this application is a component that is placed over the opening of the case 211 to isolate the internal environment of the battery cell 20 from the external environment. The shape of the cover plate 212 can be adapted to the shape of the case 211, and as shown in Figures 4 and 5, the case 211 has a rectangular parallelepiped structure, and the cover plate 212 has a rectangular plate-like structure that fits the case 211.

[0113] In the embodiments of this application, the material of the case 211 may vary, for example, copper, iron, aluminum, steel, aluminum alloy, etc. The material of the cover plate 212 may also vary, for example, copper, iron, aluminum, steel, aluminum alloy, etc. Selectively, the material of the cover plate 212 may be the same as or different from the material of the case 211.

[0114] It should be understood that the battery cell 20 further includes electrode terminals 214. The electrode terminals 214 in the embodiments of this application are used to electrically connect to an electrode assembly 22 inside the battery cell 20 to output electrical energy from the battery cell 20. As shown in Figures 4 to 5, the battery cell 20 may include at least two electrode terminals 214, which may include at least one positive electrode terminal 214a and at least one negative electrode terminal 214b, the positive electrode terminal 214a being used to electrically connect to a positive tab 222a of the electrode assembly 22, and the negative electrode terminal 214b being used to electrically connect to a negative tab 222b of the electrode assembly 22. The positive electrode terminal 214a and the positive tab 222a may be directly connected or indirectly connected, and the negative electrode terminal 214b and the negative tab 222b may be directly connected or indirectly connected. For example, the positive electrode terminal 214a can be electrically connected to the positive electrode tab 222a via a connecting component, and the negative electrode terminal 214b can be electrically connected to the negative electrode tab 222b via a connecting component.

[0115] In this battery cell 20, the electrode assembly 22 is a component that causes an electrochemical reaction in the battery cell 20, and depending on the actual usage requirements, there may be one electrode assembly 22 or multiple electrode assemblies 22 in the case 211. For example, as shown in Figures 4 and 5, two electrode assemblies 22 are installed in the battery cell 20. The electrode assembly 22 may be cylindrical, a rectangular parallelepiped, etc. If the electrode assembly 22 has a cylindrical structure, the case 211 may also have a cylindrical structure, and if the electrode assembly 22 has a rectangular parallelepiped structure, the case 211 may also have a rectangular parallelepiped structure.

[0116] It should be understood that, as shown in Figures 4 and 5, the electrode assembly 22 includes a tab 222 and an electrode body portion 221, where the tab 222 of the electrode assembly 22 may include a positive electrode tab 222a and a negative electrode tab 222b, the positive electrode tab 222a may be laminated in the portion of the positive electrode plate where the positive electrode active material layer is not coated, the negative electrode tab 222b may be laminated in the portion of the negative electrode plate where the negative electrode active material layer is not coated, and the electrode body portion 221 may be formed by laminating the positive electrode plate and the negative electrode plate together, or by winding them together.

[0117] Figure 6 shows a schematic diagram of the local structure of an electrode plate 30 according to one embodiment of the present application, and also shows the unfolded state of the electrode plate 30. For example, Figure 6 may show the electrode plate 30 before it is wound or before the electrode assembly 22 is laminated. Figure 7 shows a magnified schematic diagram of the local structure of an electrode plate 30 according to one embodiment of the present application. For example, Figure 7 may be a magnified view of region A shown in Figure 6. Figures 8 and 9 show possible cross-sectional schematic diagrams of local regions of an electrode plate 30 according to one embodiment of the present application. For example, Figures 8 and 9 may be magnified views of possible cross-sectional diagrams along the B-B' direction of region C of the electrode plate 30 shown in Figure 6.

[0118] As shown in Figures 6 to 9, the electrode plate 30 of the embodiment of this application includes a laminated segment 31 and a bendable segment 32 connected to the laminated segment 31 for bending, wherein a reinforcing structure 33 is provided in the region of the laminated segment 31 close to the bendable segment 32.

[0119] The electrode plate 30 in the embodiment of this application may be any one of the electrode plates forming the electrode assembly 22, for example, this electrode plate 30 may be a positive electrode plate or a negative electrode plate. For convenience of distinction, this electrode plate 30 will hereafter be referred to as the first electrode plate 30, that is, this first electrode plate 30 may be any one of the electrode plates included in the electrode assembly 22.

[0120] The first electrode plate 30 in the embodiment of this application includes laminated segments 31 and bent segments 32 that are connected to each other. In the process of assembling this first electrode plate 30 to form an electrode assembly 22, the first electrode plate 30 is bent at the bent segments 32, thereby stacking or winding multiple laminated segments 31 to form the electrode assembly 22. For the sake of explanation, the embodiment of this application will first be described as an example in which the electrode assembly 22 is formed without bending the first electrode plate 30.

[0121] In the embodiment of this application, a reinforcing structure 33 is installed in the region of the laminated segment 31 of the first electrode plate 30 that is close to the bent segment 32, thereby increasing the structural strength of the region of the laminated segment 31 that is close to the bent segment 32. Because the strength of the region of the laminated segment 31 that is close to the bent segment 32 is relatively high, the reinforcing structure 33 can determine the position of the bent segment 32, and in the process of bending the first electrode plate 30 to form the electrode assembly 22, the bending position of the first electrode plate 30 is restricted, so that the first electrode plate 30 is bent at the bent segment 32, the misalignment of the bending position of the first electrode plate 30 can be reduced, wrinkles in the region of the laminated segment 31 that is close to the bent segment 32 can be reduced, the processing accuracy of the electrode assembly 22 can be improved, and the processing yield and performance of the electrode assembly 22 can be improved, for example, lithium deposition phenomena due to misalignment or wrinkles of the first electrode plate 30 can be reduced, and the reliability of the electrode assembly 22 can be improved.

[0122] It should be understood that the reinforcing structure 33 of the embodiment of this application can be realized in various ways.

[0123] In some embodiments, the reinforcing structure 33 can be realized using different materials, namely, the material of the region of the laminated segment 31 where the reinforcing structure 33 is located is different from the material of other regions of the laminated segment 31, thereby further improving the structural strength of the reinforcing structure 33.

[0124] In some embodiments, the reinforcing structure 33 includes protruding structures that project from the surface of the laminated segment 31. The reinforcing structure 33 is realized by the installation of these protruding structures, making it easier to implement, and the method of forming these protruding structures can be set according to the actual application and is easy to process.

[0125] For example, the protruding structure protrudes from the first surface 311 of the laminated segment 31, and the protruding structure is recessed from the second surface 312 of the laminated segment 31, with the first surface 311 facing the second surface 312. Such a protruding structure is easy to manufacture and implement, does not require additional structures, and does not significantly increase the weight of the first electrode plate 30. As shown in Figure 8, the first electrode plate 30 In the region of the laminated segment 31 closest to the bent segment 32, a protruding structure is formed by processing such as pressing or rolling to create a reinforcing structure 33. In this way, the protruding structure protrudes from the first surface 311 of the laminated segment 31 and is recessed from the second surface 312 facing the first surface 311. That is, the reinforcing structure 33 forms a groove structure 333 on the second surface 312 of the laminated segment 31.

[0126] It should be understood that when this projection structure protrudes from the first surface 311, it means that the projection structure protrudes from areas other than the reinforcing structure 33 on the first surface 311, and correspondingly when this projection structure is recessed from the second surface 312, it means that the projection structure is recessed from areas other than the reinforcing structure 33 on the second surface 312. Since the first electrode plate 30 is generally a sheet-like structure with a relatively thin thickness, the first surface 311 and the second surface 312, which are placed opposite each other in the embodiment of this application, are surfaces perpendicular to the thickness direction T of the first electrode plate 30, that is, surfaces perpendicular to the thickness direction T of the laminated segment 31.

[0127] Furthermore, for example, the protruding structure includes a reinforcing sheet installed on the surface of the laminated segment 31. Specifically, the reinforcing sheet can be installed on at least one surface of the laminated segment 31, for example, as shown in Figure 9, the reinforcing sheet can be installed on the first surface 311 of the laminated segment 31. Depending on the actual demand, a suitable material can be selected and processed to obtain a reinforcing structure 33 of a corresponding specific strength, making the implementation method more flexible and effective. Exemplaryly, the material of this reinforcing sheet can be selected according to the actual application. For example, the material of this reinforcing sheet includes, but is not limited to, at least one of polymer plastic, nonwoven fabric, carbon fiber, and stiff paper. In some embodiments, this reinforcing sheet may be fixed to the laminated segment 31 by adhesive, or by other means such as welding.

[0128] As shown in Figures 6 to 9, regardless of the method used to realize this protrusion structure, the protrusion height T2 of the protrusion structure in the embodiment of this application relative to the laminated segment 31 can be flexibly set according to the actual application. For example, an appropriate protrusion height T2 can be set in accordance with the thickness T1 of the laminated segment 31. Here, in the embodiment of this application, the thickness T1 of the laminated segment 31 is the thickness of other areas of the laminated segment 31 other than the reinforcing structure 33, and for example, specifically, it may be the average thickness of other areas of the laminated segment 31 other than the reinforcing structure 33. The protrusion height T2 of the protrusion structure relative to the laminated segment 31 in the embodiment of this application is the distance between the surface of the protrusion structure and the surface of the laminated segment 31. For example, taking the example that the protrusion structure protrudes from the first surface 311 of the laminated segment 31, this protrusion height T2 is the distance between the surface away from the first surface 311 of the protrusion structure and the first surface 311, and for example, it may be the maximum distance or the average distance between the two surfaces.

[0129] Exemplary, the range of values ​​for the ratio of the protrusion height T2 of the protrusion structure to the thickness T1 of the laminated segment 31 is [0.3, 50], selectively [5, 40], preferably [8, 20]. Considering the requirements such as the internal energy density and performance of the battery cell 20, the range of values ​​for the thickness T1 of the laminated segment 31 is limited, and if the ratio of the protrusion height T2 to the thickness T1 of the laminated segment 31 is set too small, for example, if it is less than 0.3, the protrusion height T2 is too small, meaning the strength increased by this protrusion structure is also too small, and if the difference between the strength of this reinforcing structure 33 and the strength of other areas of the laminated segment 31 is very small, it is likely that the limiting and positioning effects of the bending segment 32 will not be obtained. Conversely, if the ratio of the protrusion height T2 to the thickness T1 of the laminated segment 31 is set too large, for example, if it exceeds 50, this protrusion height T2 is too large, increasing the distance between the multilayer plates after the first electrode plate 30 is processed into the electrode assembly 22, further reducing the space utilization rate of the electrode assembly 22 inside the battery cell 20, and reducing the energy density of the battery cell 20. On the other hand, if the protrusion structure is formed by a press method, the height T2 of the protrusion structure being pressed is too high, making the first electrode plate 30 prone to damage or breakage at the pressing point. For example, if the material of the first electrode plate 30 may contain graphite, the graphite-coated first electrode plate 30 will be more prone to breakage during pressing, further affecting the processing efficiency and yield of the first electrode plate 30 and the electrode assembly 22.

[0130] Therefore, the ratio of the projection height T2 to the thickness T1 of the laminated segment 31 of the projection structure in the embodiment of this application should not be set to be too large or too small. For example, setting the ratio of the projection height T2 to the thickness T1 of the laminated segment 31 to 0.3 or more, and further to 0.5 or more, can effectively improve the structural strength of the reinforcing structure 33, and further setting it to 8 or more can further enhance the reinforcing effect of this reinforcing structure 33. Also, for example, setting the ratio of the projection height T2 to the thickness T1 of the laminated segment 31 to 50 or less, and further to 40 or less, can reduce damage or fracture of the first electrode plate 30, and further setting it to 20 or less can improve the space utilization rate of the electrode assembly 22 using this first electrode plate 30 inside the battery cell 20, and further improve the energy density of the battery cell 20. For example, the ratio of the projection height T2 to the thickness T1 of the laminated segment 31 can be set to 0.3, 0.8, 1, 3, 5, 8, 10, 13, 15, 18, 20, 23, 25, 28, 30, 33, 35, 38, 40, 43, 45, 48, or 50, and the embodiments of this application are not limited thereto.

[0131] Exemplary, the thickness T1 of the laminated segment 31 in the embodiment of this application can be flexibly set according to the actual application. For example, if the thickness T1 of the laminated segment 31 is equal to the thickness of the bent segment 32, that is, if the thickness of the area of ​​the first electrode plate 30 other than the reinforcing structure 33 is uniform, then the thickness T1 of the laminated segment 31 is the thickness T1 of the first electrode plate 30. Alternatively, for example, the value range of the thickness T1 of the laminated segment 31 may be [6 μm, 300 μm]. Specifically, for example, the thickness T1 of the laminated segment 31 may be 6 μm, 10 μm, 30 μm, 50 μm, 80 μm, 100 μm, 130 μm, 150 μm, 180 μm, 200 μm, 230 μm, 250 μm, or 300 μm.

[0132] For example, the projection height T2 of the projection structure in the embodiment of this application relative to the laminated segment 31 can be flexibly set according to the actual application. For example, this projection structure may be a structure with uniform thickness, that is, the projection height relative to the laminated segment 31 is the same in different regions of this projection structure, making it easy to manufacture. For example, the value range of the projection height T2 of the projection structure relative to the laminated segment 31 may be [0.1 mm, 0.8 mm], and further, [0.1 mm, 0.4 mm]. For example, the projection height T2 of the projection structure relative to the laminated segment 31 may specifically be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, or 0.8 mm.

[0133] It should be understood that the strength of the reinforcing structure 33 in the embodiment of this application can be set according to the actual application. For example, the strength of the reinforcing structure 33 can be expressed by its stiffness value.

[0134] In some embodiments, the range of the ratio of the stiffness of the reinforcing structure 33 to the stiffness of other areas of the laminated segment 31 is [1.5, 65], selectively [2, 40], and preferably [10, 25]. If the ratio of the stiffness of the reinforcing structure 33 to the stiffness of other areas of the laminated segment 31 is too small, for example less than 1.5, the stiffness of the reinforcing structure 33 is greater than the stiffness of other areas of the laminated segment 31, resulting in a very small difference between the strength of the reinforcing structure 33 and the strength of other areas of the laminated segment 31. As a result, the reinforcing structure 33 is unlikely to achieve the desired restricting and positioning effect on the bending segment 32. Conversely, if the ratio of the stiffness of the reinforcing structure 33 to the stiffness of other areas of the laminated segment 31 is too large, for example greater than 65, the structural and material limitations of the laminated segment 31 itself impose an excessively high strength requirement on the reinforcing structure 33, increasing the difficulty of processing and material selection, and raising costs.

[0135] Therefore, the ratio of the stiffness of the reinforcing structure 33 to the stiffness of other areas of the laminated segment 31 in the embodiments of this application should not be too large or too small. For example, setting the ratio of the stiffnesses of the two to 1.5 or more, and further to 2 or more, improves the strength of the reinforcing structure 33, and further to 10 or more allows the strength of this reinforcing structure 33 to meet the design requirements. Alternatively, setting the ratio of the stiffnesses of the two to 65 or less, and further to 40 or less, reduces the difficulty of processing the reinforcing structure 33, and further to 25 or less makes it easier to realize this reinforcing structure 33. Furthermore, for example, the ratio of the stiffness of the reinforcing structure 33 to the stiffness of other areas of the laminated segment 31 can be set to 1.5, 2, 5, 8, 10, 13, 15, 18, 20, 23, 25, 28, 30, 33, 35, 38, 40, 43, 45, 48, 50, 53, 55, 58, 60, 63, or 65, and the embodiments of this application are not limited to these.

[0136] It should be understood that the stiffness of the reinforcing structure 33 in the embodiment of this application can be flexibly set according to the actual application. For example, the range of stiffness values ​​for the reinforcing structure 33 is [10 N / m, 300 N / m], preferably [50 N / m, 150 N / m]. Since the stiffness of the reinforcing structure 33 must be greater than the stiffness of other areas of the laminated segment 31, the stiffness value of the reinforcing structure 33 should not be too small, and generally should not be less than 10 N / m, for example, so that the reinforcing structure 33 can exert its effect of restricting and positioning the bending segment 32. Conversely, if the stiffness of the reinforcing structure 33 is set too high, for example, greater than 300 N / m, the strength requirement for the reinforcing structure 33 will be too high, making the processing and material selection of the reinforcing structure more difficult and costly.

[0137] Therefore, the rigidity of the reinforcing structure 33 must not be too high or too low. For example, the rigidity of the reinforcing structure 33 can be set to 10 N / m or more, and even 50 N / m or more, so that the reinforcing structure 33 can exert its effect of restricting and positioning the bending segment 32. Furthermore, in order to reduce the difficulty and cost of processing the reinforcing structure 33, the rigidity of the reinforcing structure 33 can be set to 300 N / m or less, and even 150 N / m or less. For example, the rigidity of the reinforcing structure 33 may be set to 10 N / m, 30 N / m, 50 N / m, 80 N / m, 100 N / m, 130 N / m, 150 N / m, 180 N / m, 200 N / m, 230 N / m, 250 N / m, 280 N / m, or 300 N / m, and the embodiments of this application are not limited to these.

[0138] It should be understood that the rigidity of the different structures in the embodiments of this application can be obtained by testing. For example, the rigidity of the reinforcing structure 33 can be obtained by the following test, but the embodiments of this application are not limited to this. First, a first pole plate 30 of a certain size is taken so that this portion of the first pole plate 30 includes at least a part of the reinforcing structure 33. For example, a first pole plate 30 with a length of approximately 30 mm can be taken, and the width in the width direction W must include the width of at least one complete reinforcing structure 33, or for example, only the width of one reinforcing structure 33. Next, this portion of the first pole plate 30 is fixed to a high-precision balance so that after this portion of the first pole plate 30 is fixed, the reinforcing structure 33 contained therein is at least 20 mm away from the fixed position along the longitudinal direction L. For example, the first pole plate 30 of this section can be fixed to the top of a 2cm*2cm rectangular parallelepiped of a high-precision balance. In addition to this 2cm*2cm fixing area, the reinforcing structure 33 of the first pole plate 30 extends at least 20mm along the longitudinal direction L. Then, a 1mm steel needle is used to vertically press down on the topmost protruding part of the reinforcing structure 33 of the first pole plate 30 until the topmost end is pushed down by 5mm, and the balance reading at this time is recorded as A(N). In this case, the stiffness value of the reinforcing structure 33 in this test is equal to A / shape variable, i.e., A / 0.005, and the unit of this stiffness value is n / m.

[0139] In the embodiment of this application, a plurality of reinforcing structures 33 are installed in the region of the laminated segment 31 near the bent segment 32, arranged along the width direction W of the first electrode plate 30, thereby increasing the structural strength of different regions in the width direction W of the first electrode plate 30. Flexed segment This reduces the possibility of localized misalignment occurring when the material is folded along section 32.

[0140] It should be understood that the positions and sizes of the multiple reinforcing structures 33 arranged along the width direction W of the first electrode plate 30 in the embodiment of this application can all be set according to the actual application.

[0141] In some embodiments, these multiple reinforcing structures 33 are arranged at equal intervals along the width direction W of the first electrode plate 30. Specifically, as shown in Figures 6 to 9, multiple reinforcing structures 33 are arranged at intervals along the width direction W of the first electrode plate 30. Here, if the pitch between the first reinforcing structure 33 and the second reinforcing structure 33 is represented by W3, and the pitch between the second reinforcing structure 33 and the third reinforcing structure 33 is represented by W4, then W3 and W4 may be equal or different. For example, by setting W3 to be equal to W4, and by analogy, the distance between two adjacent reinforcing structures 33 among the multiple reinforcing structures 33 arranged at intervals along the width direction W of the first electrode plate 30 can be set to be equal to W3. This makes processing easier and allows for a more uniform arrangement of these multiple reinforcing structures 33, thereby uniformly increasing the structural strength of different regions in the width direction W of the first electrode plate 30.

[0142] In some embodiments, the widths of the multiple reinforcing structures 33, which are spaced apart in the width direction W of the first electrode plate 30, are equal. Specifically, as shown in Figures 6 to 9, the width of each of the multiple reinforcing structures 33, which are spaced apart in the width direction W of the first electrode plate 30, can be set to be equal to W2. This makes processing easier, while also making the arrangement of these multiple reinforcing structures 33 more uniform and the structural strength distribution more uniform.

[0143] In some embodiments, these multiple reinforcing structures 33 protrude from the surface of the laminated segment 31 and their protrusion directions coincide. When the multiple reinforcing structures 33 are configured to protrude from other areas of the laminated segment 31 other than these reinforcing structures 33, they occupy the space between different electrode plate layers of the electrode assembly 22 formed by the first electrode plate 30. When the protrusion directions of the multiple reinforcing structures 33 aligned along the width direction W of the first electrode plate 30 coincide, these multiple reinforcing structures 33 occupy the space on the same side of the first electrode plate 30, reducing the gaps between the multilayer structures of the electrode assembly 22, and further improving the space utilization rate of the electrode assembly 22 within the battery cell 20, thereby improving the energy density of the battery cell 20.

[0144] In the embodiments of this application, the width of the reinforcing structure 33 can be flexibly set according to the actual application. For example, the range of the ratio of the sum of the widths of all reinforcing structures 33 arranged along the width direction W of the first pole plate 30 to the width W1 of the first pole plate 30 is [1 / 3, 0.8], preferably [0.4, 0.6]. Specifically, if a plurality of reinforcing structures 33 are arranged along the width direction W of the first pole plate 30 and the widths of these plurality of reinforcing structures 33 are equal, the sum of the widths of all reinforcing structures 33 arranged along the width direction W of the first pole plate 30 is equal to the number obtained by multiplying the width of each reinforcing structure 33 by the number of reinforcing structures 33. For example, as shown in Figures 6 to 9, if eight reinforcing structures 33 are arranged along the width direction W of the first pole plate 30 and the width of each of these plurality of reinforcing structures 33 is W2, the sum of the widths of all reinforcing structures 33 arranged along the width direction W of the first pole plate 30 is equal to 8*W2.

[0145] If the ratio of the sum of the widths of all the reinforcing structures 33 aligned along the width direction W of the first electrode plate 30 in the embodiment of this application to the width W1 of the first electrode plate 30 is set too small, for example, if it is less than 1 / 3, then the reinforcing structures 33 will not be installed in most of the area of ​​the first electrode plate 30 in the width direction W. When the first electrode plate 30 is bent, misalignment is likely to occur in this area, which may affect the processing yield of the electrode assembly 22 and potentially affect the performance of the electrode assembly 22. Conversely, if the ratio of the sum of the widths of all the reinforcing structures 33 aligned along the width direction W of the first electrode plate 30 to the width W1 of the first electrode plate 30 is set too large, for example, if it is greater than 0.8, then the area occupied by the reinforcing structures 33 will be too large, which may affect the strength of this area. In particular, when the reinforcing structures 33 are installed by a press method, the reinforcing structures 33 will be located on the first electrode plate. 30 If the distribution is too strong along the width direction W, it may not be effective in reinforcing the structural strength of the region of the laminated segment 31 that is close to the bent segment 32. Furthermore, when the first electrode plate 30 is bent, misalignment may still occur, which may affect the processing yield of the electrode assembly 22 and the performance of the electrode assembly 22.

[0146] Therefore, the ratio of the sum of the widths of all the reinforcing structures 33 aligned along the width direction W of the first electrode plate 30 to the width W1 of the first electrode plate 30 must not be too large or too small. For example, setting this ratio to 1 / 3 or more, and further setting it to 0.4 or more, can reduce the risk of local displacement of the first electrode plate 30. Alternatively, setting this ratio to 0.8 or less, and further setting it to 0.6 or less, can improve the effectiveness of the reinforcing structures 33. Specifically, for example, this ratio may be set to 1 / 3, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, or 0.8.

[0147] In the embodiments of this application, for any one of the reinforcing structures 33, the ratio of the width W2 of the first electrode plate 30 of the reinforcing structure 33 along the width direction W to the width W1 of the first electrode plate 30 can be set according to the actual application. For example, the ratio of the width W2 of the reinforcing structure 33 to the width W1 of the first electrode plate 30 should not be made too small, as the width W1 of the first electrode plate 30 is limited. If this ratio is set too small, the difficulty of processing the reinforcing structure 33 will be greatly increased, and the strength of the reinforcing structure 33 will be reduced. Therefore, the ratio of the width W2 of the reinforcing structure 33 to the width W1 of the first electrode plate 30 is generally set to 0.0025 or more, and can be set to 0.01 or more.

[0148] In the embodiments of this application, as shown in Figures 6 to 9, the range of the ratio between the shortest length L3 between the end of the reinforcing structure 33 near the bent segment 32 and the center line Lb of the bent segment 32 and the thickness T1 of the first electrode plate 30 is [0.016, 0.5], preferably [0.05, 0.4]. Specifically, the center line Lb of the bent segment 32 in the embodiments of this application is perpendicular to the longitudinal direction L of the first electrode plate 30 and is located in the intermediate region of the bent segment 32. The thickness T1 of the first electrode plate 30 in the embodiments of this application may be equal to the thickness of the region of the laminated segment 31 other than the reinforcing structure 33, or it may be equal to the thickness of the bent segment 32, and the embodiments of this application are not limited to these.

[0149] If the ratio of the minimum length L3 to the thickness T1 of the first electrode plate 30 is too small, the reinforcing structure 33 will be too close to the center line Lb of the bending segment 32, as the thickness T1 of the first electrode plate 30 is generally relatively thin. When the first electrode plate 30 is bent, the range of the bending segment 32 restricted by the reinforcing structure 33 will be too small, making it difficult to bend the first electrode plate 30 and increasing the difficulty of processing the electrode assembly 22. Furthermore, if a notch 34 is placed in the intermediate region of the bending segment 32, the reinforcing structure 33 will affect the area surrounding the notch 34 of the bending segment 32, improving the difficulty of processing the notch 34. Conversely, if the ratio of the minimum length L3 to the thickness T1 of the first electrode plate 30 is too large, the reinforcing structure 33 will be too far from the center line Lb of the bending segment 32, making it difficult for the reinforcing structure 33 to perform its role in limiting the bending segment 32. This will still make misalignment more likely when the first electrode plate 30 is bent, further affecting the processing efficiency and yield of the electrode assembly 22.

[0150] Therefore, the ratio of this shortest length L3 to the thickness T1 of the first pole plate 30 must not be too large or too small. For example, by setting the ratio of the shortest length L3 between the end of the reinforcing structure 33 near the bending segment 32 and the center line Lb of the bending segment 32 to the thickness T1 of the first pole plate 30 to 0.016 or more, or even 0.05 or more, the bending efficiency of the first pole plate 30 can be increased. Alternatively, by setting the ratio of this shortest length L3 to the thickness T1 of the first pole plate 30 to 0.5 or less, or even 0.4 or less, the possibility of misalignment still occurring when the first pole plate 30 is bent can be reduced. For example, the ratio of the shortest length L3 to the thickness T1 of the first electrode plate 30 can be set to 0.016, 0.03, 0.05, 0.08, 0.1, 0.13, 0.15, 0.18, 0.2, 0.23, 0.25, 0.28, 0.3, 0.33, 0.35, 0.38, 0.4, 0.43, 0.45, 0.48, or 0.5.

[0151] In some embodiments, the minimum length L3 between the end of the reinforcing structure 33 near the bent segment 32 and the centerline Lb of the bent segment 32 can be set according to the actual application. For example, the range of values ​​for this minimum length L3 can be set to [0.5 mm, 3 mm], and further, the range of values ​​for the minimum length L3 can be set to [1 mm, 2 mm]. Alternatively, for example, the minimum length L3 can be set to be equal to 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, or 3 mm.

[0152] In some embodiments, when multiple reinforcing structures 33 are arranged in the width direction W of the first electrode plate 30, the shortest lengths between the ends of these multiple reinforcing structures 33 near the bent segment 32 and the center line Lb of the bent segment 32 can be set to be equal or different. For example, by setting them to be equal, the positional distribution of these multiple reinforcing structures 33 in the width direction W of the first electrode plate 30 becomes more uniform, and the effect of the reinforcing structures 33 can be improved.

[0153] In the embodiments of this application, the size of the reinforcing structure 33 along the longitudinal direction L of the first electrode plate 30 can be set according to the actual application. For example, the reinforcing structure 33 does not pass through the center line La in the longitudinal direction L of the first electrode plate 30 of the laminated segment 31, and the range of the ratio of the span L2 of the reinforcing structure 33 along the longitudinal direction L of the first electrode plate 30 to the length L1 of the laminated segment 31 is [10%, 50%]. Specifically, as shown in Figures 6 to 9, the center line La in the longitudinal direction L of the first electrode plate 30 of the laminated segment 31 is perpendicular to the longitudinal direction L of the first electrode plate 30, and the laminated segment 31 center lineLa is located in the intermediate region of the laminated segment 31. If the opposing ends of the first electrode plate 30 of the laminated segment 31 along the longitudinal direction L may be connected to a bent segment 32, then reinforcing structures 33 may be installed at both opposing ends of the first electrode plate 30 of the laminated segment 31 along the longitudinal direction L. The reinforcing structure 33 at one end of the laminated segment 31 that is close to the bent segment 32 can be configured so that it does not pass through the center line La in the longitudinal direction L of the first electrode plate 30 of the laminated segment 31, thereby avoiding affecting the reinforcing structure 33 at the other end of the laminated segment 31.

[0154] Since the reinforcing structure 33 does not pass through the center line La in the longitudinal direction L of the first pole plate 30 of the laminated segment 31, the ratio of the span L2 of the reinforcing structure 33 along the longitudinal direction L of the first pole plate 30 to the length L1 of the laminated segment 31 is less than 50%. The ratio of the span L2 of the reinforcing structure 33 along the longitudinal direction L of the first pole plate 30 to the length L1 of the laminated segment 31 should not be too small. For example, generally setting this ratio to 10% or more ensures that the span L2 of the reinforcing structure 33 is sufficiently large, thereby improving the reinforcing effect of the reinforcing structure 33. For example, the ratio of the span L2 of the reinforcing structure 33 along the longitudinal direction L of the first pole plate 30 to the length L1 of the laminated segment 31 can generally be set to 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 48%.

[0155] Figure 10 shows a schematic diagram of the local structure of the first electrode plate 30 in another embodiment of the present application, and also shows the unfolded state of the first electrode plate 30, for example, Figure 10 may show the electrode plate 30 before it is wound up or before the electrode assembly 22 is laminated. As shown in Figure 10, the reinforcing structure 33 can employ the installation method shown in Figure 10. Specifically, considering that both opposing ends of the first electrode plate 30 of the laminated segment 31 along the longitudinal direction L may each be connected to the bent segment 32, if the reinforcing structure 33 is installed in the region close to the bent segment 32 at both ends of the laminated segment 31, the reinforcing structure 33 can be set to pass through the center line La in the longitudinal direction L of the first electrode plate 30 of the laminated segment 31.

[0156] Correspondingly, as shown in Figures 6 to 10, the range of the ratio between the span L2 of the first pole plate 30 of the reinforcing structure 33 along the longitudinal direction L and the length L1 of the laminated segment 31 is [10%, 100%]. Since the reinforcing structure 33 can pass through the center line La in the longitudinal direction L of the first pole plate 30 of the laminated segment 31, the ratio between the span L2 of the first pole plate 30 of the reinforcing structure 33 along the longitudinal direction L and the length L1 of the laminated segment 31 may be 100% or less. The ratio between the span L2 of the first pole plate 30 of the reinforcing structure 33 along the longitudinal direction L and the length L1 of the laminated segment 31 should not be made too small. For example, generally, setting this ratio to 10% or more ensures that the span L2 of the reinforcing structure 33 is sufficiently large, thereby improving the reinforcing effect of the reinforcing structure 33. For example, the ratio of the span L2 along the longitudinal direction L of the first pole plate 30 of the reinforcing structure 33 to the length L1 of the laminated segment 31 can generally be set to 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 100%.

[0157] In the embodiments of this application, the reinforcing structure 33 is installed at an inclination with respect to the width direction W of the first pole plate 30. The reinforcing structure 33 in the embodiments of this application is a strip-like structure, and this reinforcing structure 33 is installed at an inclination with respect to the width direction W of the first pole plate 30, that is, the extending direction of this reinforcing structure 33 is different from the width direction W of the first pole plate 30, or the extending direction of this reinforcing structure 33 is not parallel to the width direction W of the first pole plate 30.

[0158] If the reinforcing structure 33 is set so as not to be inclined with respect to the width direction W of the first pole plate 30, the reinforcing structure 33 will not be able to exert its reinforcing effect, and when the first pole plate 30 is bent, the reinforcing structure 33 will not be able to effectively limit the position of the bending segment 32. Therefore, by setting the reinforcing structure 33 to be inclined with respect to the width direction W of the first pole plate 30, the reinforcing structure 33 can have a reinforcing effect in the width direction W perpendicular to the first pole plate 30, thereby limiting the position in which the first pole plate 30 is bent.

[0159] In some embodiments, the inclination angle of the reinforcing structure 33 with respect to the width direction W of the first pole plate 30 can be set according to the actual application. For example, the range of values ​​for the angle α between the reinforcing structure 33 and the first pole plate 30 in the width direction W is [45°, 135°]. If this angle α is set to be too large or too small, for example, less than 45° or greater than 135°, the reinforcing effect of the reinforcing structure 33 in the width direction W perpendicular to the first pole plate 30 will be much smaller than the reinforcing effect in the width direction W parallel to the first pole plate 30, thereby reducing the role of the reinforcing structure 33 in preventing buckling and displacement.

[0160] Therefore, the angle α must not be set to be too large or too small. For example, the range of values ​​for the angle α may be [45°, 135°], or [60°, 120°], or the effect of the reinforcing structure 33 can be improved by setting this angle α to 90°. This angle α can be set to 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, 85°, 90°, 95°, 100°, 105°, 110°, 115°, 120°, 125°, 130°, or 135°.

[0161] In the embodiment of this application, the first electrode plate 30 includes a plurality of laminated segments 31, and the bent segment 32 is connected to the first laminated segment 313 and the second laminated segment 314 of the plurality of laminated segments 31, and reinforcing structures 33 are installed in the region of the first laminated segment 313 and the region of the second laminated segment 314 that is close to the bent segment 32. Specifically, as shown in Figures 6 to 10, two laminated segments 314 are connected to the bent segment 32, and in this way, when the first electrode plate 30 is bent at the bent segment 32, the two laminated segments 31 can be stacked and installed along the thickness direction T of the laminated segment 31 so that they are used to form an electrode assembly 22. When reinforcing structures 33 are installed in the region of the first laminated segment 313 close to the bent segment 32 and in the region of the second laminated segment 314 close to the bent segment 32, the region between the reinforcing structure 331 of the first laminated segment 313 and the reinforcing structure 332 of the second laminated segment 314 includes the bent segment 32. That is, by restricting the position of the bent segment 32 together with the reinforcing structure 331 of the first laminated segment 313 and the reinforcing structure 332 of the second laminated segment 314, when the first electrode plate 30 is bent, the misalignment, bending, and wrinkling of the first laminated segment 313 and the second laminated segment 314 are reduced, the bent segment 32 can be positioned more accurately, improving the processing efficiency and yield of the electrode assembly 22 and further improving the performance of the battery cell 20.

[0162] It should be understood that the reinforcing structure 331 installed on the first laminated segment 313 applies to all descriptions of installing the reinforcing structure 33 on the laminated segment 33 described above, and similarly, the reinforcing structure 332 installed on the second laminated segment 314 also applies to all descriptions of installing the reinforcing structure 33 on the laminated segment 33 described above, and for the sake of brevity, its explanation is omitted here.

[0163] Furthermore, the reinforcing structure 331 installed near the bent segment 32 of the first laminated segment 313 in the embodiment of this application may or may not have the same parameters as the reinforcing structure 332 installed near the bent segment 32 of the second laminated segment 314, such as position, number, size, and shape. For example, the reinforcing structure 331 of the first laminated segment 313 may have the same size and shape as the reinforcing structure 332 of the second laminated segment 314, making it easy to manufacture.

[0164] Furthermore, for example, the positions of the reinforcing structure 331 of the first laminated segment 313 and the reinforcing structure 332 of the second laminated segment 314 in the width direction W of the first electrode plate 30 are installed correspondingly. Specifically, as shown in Figures 6 to 9, the positions of the reinforcing structure 331 of the first laminated segment 313 and the reinforcing structure 332 of the second laminated segment 314 in the width direction W of the first electrode plate 30 are installed correspondingly, that is, the positions of the reinforcing structure 331 of the first laminated segment 313 and the reinforcing structure 332 of the second laminated segment 314 are approximately symmetrical with respect to the bending segment 32. In this way, when the first electrode plate 30 is bent along the bending segment 32, the reinforcing structure 331 of the first laminated segment 313 and the reinforcing structure 332 of the second laminated segment 314 can basically overlap, resulting in a simple structure and easy processing.

[0165] Furthermore, for example, the positions of the reinforcing structure 331 of the first laminated segment 313 and the reinforcing structure 332 of the second laminated segment 314 of the first electrode plate 30 in the width direction W are offset. Specifically, Figure 11 shows a schematic diagram of the local structure of the first electrode plate 30 in yet another embodiment of the present application, and Figure 11 shows the unfolded state of the first electrode plate 30, for example, Figure 11 may show the first electrode plate 30 before it is wound up or before the electrode assembly 22 is laminated. Unlike the installation method of the reinforcing structure 33 shown in Figure 6, as shown in Figures 10 and 11, the reinforcing structure 331 of the first laminated segment 313 and the reinforcing structure 332 of the second laminated segment 314 can be installed offset from each other. That is, the positions of the reinforcing structure 331 of the first laminated segment 313 and the reinforcing structure 332 of the second laminated segment 314 are asymmetrical with respect to the bending segment 32. Furthermore, when the first electrode plate 30 is bent along the bending segment 32, the reinforcing structure 331 of the first laminated segment 313 and the reinforcing structure 332 of the second laminated segment 314 cannot completely overlap. For example, as shown in Figure 10, some areas may overlap and some areas may not overlap, or as shown in Figure 11, they may not overlap at all. In this way, the positioning of the reinforcing structure 331 of the first laminated segment 313 and the reinforcing structure 332 of the second laminated segment 314 becomes more flexible. When the first electrode plate 30 is bent to form the electrode assembly 22, the space occupied by the reinforcing structure 331 of the first laminated segment 313 and the reinforcing structure 332 of the second laminated segment 314 can be adjusted, the space between different electrode plate layers can be used rationally, the space utilization rate of the electrode assembly 22 inside the battery cell 20 can be improved, and the energy density of the battery cell 20 can be further improved.

[0166] In some embodiments, the reinforcing structures 331 of the first laminated segment 313 and the reinforcing structures 332 of the second laminated segment 314 are arranged at equal intervals along the width direction W of the first pole plate 30. Specifically, in the case where they are installed in correspondence as shown in Figures 6 to 9, the reinforcing structures 331 of the first laminated segment 313 and the reinforcing structures 332 of the second laminated segment 314 are arranged at equal intervals along the width direction W of the first pole plate 30, and the spacing between the multiple reinforcing structures 331 arranged along the width direction W of the first pole plate 30 of the first laminated segment 313 is equal, and correspondingly, the spacing between the multiple reinforcing structures 332 arranged along the width direction W of the first pole plate 30 of the second laminated segment 314 is also equal. In the case of the misalignment shown in Figure 11, the reinforcing structure 331 of the first laminated segment 313 and the reinforcing structure 332 of the second laminated segment 314 are arranged at equal intervals in the width direction W of the first electrode plate 30. The distances between the two closest reinforcing structures 332 of the first reinforcing structure 331 of the first laminated segment 313 are W5 and W6, and W5 is equal to W6. Similarly, the distances between the two closest reinforcing structures 331 of the second reinforcing structure 332 of the second laminated segment 314 are W6 and W7, and W6 is equal to W7. By analogy, the distance between any one of the reinforcing structures 331 of the first laminated segment 313 and the closest reinforcing structure 332 of the second laminated segment 314 is W5.

[0167] By setting the reinforcing structure 331 of the first laminated segment 313 and the reinforcing structure 332 of the second laminated segment 314 to be aligned at equal intervals in the width direction W of the first electrode plate 30, the reinforcing structure 331 of the first laminated segment 313 and the reinforcing structure 332 of the second laminated segment 314 can be aligned uniformly, making processing easier and allowing for a uniform distribution of the reinforcing structures 33. This reduces the risk of misalignment occurring in different regions of the first laminated segment 313 and the second laminated segment 314 when the first electrode plate 30 is bent, thereby improving the processing efficiency and yield of the electrode assembly 22.

[0168] In some embodiments, the reinforcing structure 331 of the first laminated segment 313 includes a projection that protrudes from the surface of the first laminated segment 313, and the reinforcing structure 332 of the second laminated segment 314 includes a projection that protrudes from the surface of the second laminated segment 314, and the projection direction of the reinforcing structure 331 of the first laminated segment 313 is opposite to the projection direction of the reinforcing structure 332 of the second laminated segment 314. Thus, after the first electrode plate 30 is bent along the bending segment 32, the first laminated segment 313 and the second laminated segment 314 are installed in a laminated manner, and the projection direction of the reinforcing structure 331 of the first laminated segment 313 coincides with the projection direction of the reinforcing structure 332 of the second laminated segment 314, and the reinforcing structure 332 of the second laminated segment 314 is... Stacked segments If the reinforcing structure 331 of the first laminated segment 313 protrudes from one side of the surface of 314 and is recessed from the other side of the surface of the second laminated segment 314, then the portion of the reinforcing structure 331 of the first laminated segment 313 that protrudes from the surface of the first laminated segment 313 is the second Stacked segments The reinforcing structure 332 of 314 can be accommodated in the recessed portion, and the gap between different electrode layers can be reduced. For example, if both the first laminated segment 313 and the second laminated segment 314 form a protruding reinforcing structure 33 by means of a press or the like, one surface of the reinforcing structure 33 protrudes from the other area of ​​the laminated segment 31, while the other surface is recessed into the other area of ​​the laminated segment 31. After the first electrode plate 30 is bent along the bending segment 32, if there is at least a partial overlap between the reinforcing structure 331 of the first laminated segment 313 and the reinforcing structure 332 of the second laminated segment 314, and their protruding directions coincide, the protruding portion of the reinforcing structure 331 of the first laminated segment 313 may be located in the recessed portion of the reinforcing structure 332 of the second laminated segment 314, or the protruding portion of the reinforcing structure 332 of the second laminated segment 314 may be located in the recessed portion of the reinforcing structure 331 of the first laminated segment 313, thereby saving space between the two laminated segments 31, i.e., reducing the distance between the two laminated segments 31, improving the space utilization rate of this electrode assembly 22 inside the battery cell 20, and further improving the energy density of the battery cell 20.

[0169] Figure 12 shows a schematic local structure of the first electrode plate 30 in yet another embodiment of the present application, and Figure 12 shows the unfolded state of the first electrode plate 30, for example, Figure 12 may show the first electrode plate 30 before it is wound or before the electrode assembly 22 is laminated. Figure 13 is a local enlarged view of the first electrode plate 30 in yet another embodiment of the present application, for example, Figure 13 is an enlarged view of region D in Figure 12.

[0170] As shown in Figures 12 and 13, unlike in Figure 6, the bent segment 32 is provided with a notch 34 that extends along the width direction W of the first electrode plate 30. The provided notch 34 enables the positioning of the bent segment 32, reduces the offset at the bending point of the first electrode plate 30, and further reduces the offset between different electrode plates of the electrode assembly 22. At the same time, the notch 34 reduces the difficulty of bending, reduces resistance during bending, and further improves the processing efficiency of the electrode assembly 22.

[0171] It should be understood that the difference between Figure 12 and Figure 6 of the embodiment of this application is the cutout 34, and the other structures of Figure 12 are applicable to the related descriptions in Figures 6 through 9, and for the sake of brevity, their explanation is omitted here.

[0172] In the embodiments of this application, the structure of the notch 34 can be flexibly configured according to the actual application. For example, the notch 34 may be a through-hole, which is easy to process and can significantly reduce resistance during bending, thereby improving the processing efficiency of the electrode assembly 22. Alternatively, the notch 34 may be a groove. This can reduce resistance during bending and reduce the loss of structural strength of the first electrode plate 30 of the electrode assembly 22.

[0173] Furthermore, if the notch 34 is a groove, this groove can be realized in various ways. For example, if the groove can be realized by locally thinning the first electrode plate 30, the thickness of the bottom wall of this groove is smaller than the thickness of the area of ​​the first electrode plate 30 other than the groove. Also, for example, the direction of the opening of this groove can be flexibly set according to the actual application. For example, after bending the first electrode plate 30, the opening of this groove may face toward the center of the electrode assembly 22, or it may face away from the center of the electrode assembly 22, and the embodiments of this application are not limited to these.

[0174] In some embodiments, the bending of the embodiments of this application segment If 32 includes a plurality of notches 34, for example, a plurality of notches 34 aligned along the width direction W of the first electrode plate 30, the structural types of these plurality of notches 34 may be the same or different. For example, some of the notches 34 may be set as through holes and some of the notches 34 as grooves, or all of the notches 34 may be set as through holes, and the embodiments of this application are not limited thereto.

[0175] In the embodiments of this application, the number of notches 34 includes a plurality, and the reinforcing structure 33 corresponds to the connection area between two adjacent notches 34 among the plurality of notches 34, so that the reinforcing structure 33 and the plurality of notches 34 engage with each other, jointly positioning and restricting the position of the bent segment 32, improving the structural strength of the region surrounding the bent segment 32 of the first electrode plate 30, thereby avoiding as much as possible the occurrence of misalignment or wrinkles in different regions along the width direction W of the first electrode plate 30 when the first electrode plate 30 is bent, and improving the processing efficiency and yield of the electrode assembly 22.

[0176] It should be understood that the size of the notches 34 in the embodiments of this application can be set according to the actual application. Figure 14 shows a schematic diagram of the local structure of the first electrode plate 30 in yet another embodiment of this application, and Figure 14 shows the unfolded state of the first electrode plate 30, for example, the first electrode plate 30 may be unrolled or in a state before the electrode assembly 22 is laminated. Also, for the sake of explanation, Figure 14 shows only the multiple notches 34 arranged along the width direction W of the first electrode plate 30, but does not show the reinforcing structure 33, however the first electrode plate 30 can similarly be fitted with the reinforcing structure 33 and applied to the relevant description above, and for the sake of brevity, it will not be described further here.

[0177] As shown in Figure 14, the number of notches 34 includes multiple notches 34, which include edge notches 341 located at both ends along the width direction W of the first electrode plate 30 and intermediate notches 342 located in the middle region of the first electrode plate 30, wherein the length W10 of the edge notches 341 along the width direction W of the first electrode plate 30 is greater than the length W20 of the intermediate notches 342 along the width direction W of the first electrode plate 30. When the bending segment 32 of the first electrode plate 30 is bent, the resistance at both end edge positions along the width direction W of the first electrode plate 30 is greater than the resistance at the intermediate position, and considering that the variation in the fold at the edge position of the first electrode plate 30 is greater, by setting the length W10 along the width direction W of the edge cut 341 to be greater than the length W20 along the width direction W of the intermediate cut 342, the resistance at the edge position of the first electrode plate 30 can be reduced more significantly, the variation can be reduced, and the probability of offset when the first electrode plate 30 is bent can be reduced, thereby reducing the possibility of active material deposition or failure of the electrode assembly 22, and improving the processing efficiency and yield of the electrode assembly 22.

[0178] It should be understood that the width direction W of the first electrode plate 30 in the embodiment of this application may be vertical upward as shown in Figure 14, and since both ends of the first electrode plate 30 along this width direction W include the upper edge and lower edge of the first electrode plate 30 as shown in Figure 14, the plurality of notches 34 in the embodiment of this application may include at least one edge notch 341 located near the upper edge and / or at least one edge notch 341 located near the lower edge.

[0179] Furthermore, if these multiple notches 34 include multiple edge notches 341, the lengths of these multiple edge notches 341 along the width direction W of the first electrode plate 30 may be equal or different. In the embodiments of this application, the length W10 of the edge notches 341 along the width direction W of the first electrode plate 30 may refer to the average, minimum, or maximum value of the lengths of the multiple edge notches 341 along the width direction W. For example, as shown in Figure 14, if these multiple notches 341 include two edge notches 341, and the length along the width direction W of the upper edge notch 341 is W11 and the length along the width direction W of the lower edge notch 341 is W12, then the length W10 of the edge notches 341 along the width direction W of the first electrode plate 30 in the embodiments of this application may be the minimum value of W11 and W12, but the embodiments of this application are not limited to this.

[0180] Similar to the edge notch 341, the notch 34 in the embodiments of this application may include at least one intermediate notch 342 located in the intermediate region of the first electrode plate 30. If the notch 34 includes a plurality of intermediate notches 342, the lengths of these plurality of intermediate notches 342 along the width direction W of the first electrode plate 30 may be equal or different, and the length W20 of the intermediate notch 342 along the width direction W of the first electrode plate 30 in the embodiments of this application may refer to the average, minimum, or maximum value of the lengths of the plurality of intermediate notches 342 along the width direction W. For example, as shown in Figure 14, if the multiple cuts 342 include five intermediate cuts 342, and the lengths of the five intermediate cuts 342 along the width direction W are W21, W22, W23, W24, and W25 respectively, then these five intermediate cuts 342 can be set so that the lengths W21, W22, W23, W24, and W25 are all equal, making machining easy. Also, for example, as shown in Figure 14, if the lengths of the five intermediate cuts 342 along the width direction W are still W21, W22, W23, W24, and W25 respectively, the length W20 of the intermediate cut 342 along the width direction W in the embodiment of this application may be the maximum value between lengths W21 and W25, but the embodiment of this application is not limited to this.

[0181] In some embodiments, when multiple notches 34 include multiple intermediate notches 342, the spacing between the multiple intermediate notches 342 along the width direction W of the first electrode plate 30 may or may not be equal. Specifically, as shown in Figure 14, taking as an example that these multiple notches 34 include five intermediate notches 342, and the pitch lengths along the width direction W between these five intermediate notches 342 are D12, D23, D34, and D45 respectively, then it is possible to set these five intermediate notches 342 to satisfy the condition that the spacing distances D12, D23, D34, and D45 are all equal.

[0182] In this way, by setting the lengths of the multiple intermediate cuts 342 along the width direction W to be equal, the number of times the size accuracy of the different intermediate cuts 342 is adjusted can be reduced, thereby lowering the difficulty of machining. By setting the intervals between the multiple intermediate cuts 342 along the width direction W to be equal, that is, by setting the intermediate cuts 342 to be uniformly distributed along the width direction W, the intermediate region of the first electrode plate 30 receives force uniformly along the width direction W, making it easier to bend, which reduces the difficulty of machining the electrode assembly 22 and further improves the machining efficiency and yield of the electrode assembly 22.

[0183] In the embodiments of this application, the size of the notches 34 can be set in a different manner than that shown in Figure 14. For example, the number of notches 34 may include multiple notches, and the lengths of the multiple notches 34 are equal along the width direction W of the first electrode plate 30. By setting the size of the multiple notches 34 aligned along the width direction W to be equal, the number of times the size of the notches 34 to be processed can be reduced, thereby lowering the difficulty of processing and improving processing efficiency.

[0184] In some embodiments, the notch 34 is located in the center of the bending segment 32 along the longitudinal direction L of the first electrode plate 30. Specifically, as shown in Figures 12 to 14, by setting the notch 34 to be located in the center of the bending segment 32 along the longitudinal direction L of the first electrode plate 30, or in the center along the bending direction of the bending segment 32, the positioning becomes more accurate when the first electrode plate 30 is bent along the notch 34 in which it is installed, thereby minimizing the displacement and offset of the first electrode plate 30 and improving the processing efficiency and yield of the electrode assembly 22.

[0185] In the embodiments of this application, the first electrode plate 30 may be used to fabricate and form the electrode assembly 22, and for example, the first electrode plate 30 may be a positive electrode plate or a negative electrode plate.

[0186] In some embodiments, the first electrode plate 30 is a negative electrode plate without a negative electrode. Specifically, the first electrode plate 30 may include a negative electrode current collector, but the two opposing surfaces of this negative electrode current collector are not coated with negative electrode active material. In this way, the thickness of the first electrode plate 30 is reduced, and when assembled into the electrode assembly 22 and installed in the battery cell 20, the space utilization rate of the electrode assembly 22 is improved, and the energy density of the battery cell 20 can be further improved. Furthermore, because the thickness of the first electrode plate 30 is reduced, misalignment or wrinkling is more likely to occur when the first electrode plate 30 is bent, and the installed reinforcing structure 33 can effectively reduce misalignment and wrinkling, thereby improving the processing efficiency and yield of the electrode assembly 22.

[0187] In some embodiments, the thickness of the negative electrode plate without a negative electrode is relatively thin, and its thickness can be flexibly set according to the actual application. For example, the range of values ​​for the thickness of the negative electrode plate without a negative electrode is generally [4 μm, 30 μm], and for example, the thickness of the negative electrode plate without a negative electrode can be further set to [5 μm, 17 μm], and for example, the thickness of the negative electrode plate without a negative electrode may generally be set to 4 μm, 5 μm, 6 μm, 8 μm, 10 μm, 12 μm, 15 μm, 17 μm, 20 μm, 22 μm, 25 μm, 27 μm, or 30 μm.

[0188] For example, the negative electrode current collector can be a metal foil sheet, foamed metal, or a composite current collector. For example, as the metal foil sheet, silver-surface-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium can be used. The composite current collector may include a polymer material base layer and a metal layer. The foamed metal may be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (for example, a substrate such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, or polyethylene).

[0189] In some implementations, the battery cell formed by employing a negative electrode plate without a negative electrode in the embodiment of this application may be a sodium secondary battery without a negative electrode.

[0190] A sodium secondary battery without a negative electrode is a battery constructed without a negative electrode active material layer being spontaneously formed on the negative electrode plate side during the battery's manufacturing process. For example, the negative electrode active material layer is formed without the installation of a sodium metal or carbonaceous active material layer by processes such as coating or deposition on the negative electrode during the battery's manufacturing process. During the initial charge, sodium ions gain electrons on the anode side, and metallic sodium deposits a sodium metallic phase on the current collector surface. During discharge, the metallic sodium transforms into sodium ions and returns to the positive electrode, enabling cyclic charging and discharging. Compared to other sodium secondary batteries, a sodium secondary battery without a negative electrode can achieve a higher energy density because it lacks a negative electrode active material layer.

[0191] In some implementations, to improve battery performance, the negative electrode side of a sodium secondary battery without a negative electrode is provided with several functional coatings, such as carbonaceous materials, metal oxides, or alloys, to improve the conductivity of the negative electrode current collector and enhance the uniformity of the deposited sodium metal.

[0192] In some implementation methods, the CB value of a sodium secondary battery without a negative electrode is 0.1 or less.

[0193] Specifically, the CB value is the capacity per unit area of ​​the negative electrode plate in a secondary battery divided by the capacity per unit area of ​​the positive electrode plate. Batteries without a negative electrode do not contain functional coatings, or only contain small amounts of functional coatings, so the capacity per unit area of ​​the negative electrode plate is relatively small, and the CB value of such secondary batteries is 0.1 or less.

[0194] In some embodiments, the first electrode plate 30 may be a negative electrode plate, and this negative electrode plate may further include a negative electrode current collector and a negative electrode active material placed on at least one surface of the negative electrode current collector.

[0195] For example, the negative electrode current collector has two opposing surfaces in the thickness direction of itself, and the negative electrode active material is placed on one or both of the two opposing surfaces of the negative electrode current collector.

[0196] For example, the negative electrode active material can be a negative electrode active material known in the art for use in battery cells. For example, the negative electrode active material may include at least one material from among artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate.

[0197] In some embodiments, the first electrode plate 30 may be a positive electrode plate, which may include a positive electrode current collector and a positive electrode active material placed on at least one surface of the positive electrode current collector.

[0198] For example, a positive electrode current collector has two opposing surfaces in the direction of its own thickness, and the positive electrode active material is placed on one or both of the two opposing surfaces of the positive electrode current collector.

[0199] For example, the positive electrode current collector may be a metal foil sheet or a composite current collector. For example, as the metal foil sheet, silver-surface-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium can be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may be formed by forming a metal material (such as aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy) on a polymer material substrate (for example, a substrate such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, or polyethylene).

[0200] For example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphate, lithium transition metal oxide, and their respective reformed compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used individually or in combination of two or more. Here, examples of lithium-containing phosphates may include, but are not limited to, at least one of the following: lithium iron phosphate (e.g., LiFePO4 (which may be abbreviated as LFP)), composite materials of lithium iron phosphate and carbon, lithium manganese phosphate (e.g., LiMnPO4), composite materials of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and composite materials of lithium iron manganese phosphate and carbon.

[0201] In the embodiments of this application, the electrode assembly 22 can be formed by bending the first electrode plate 30. Specifically, Figure 15 shows a schematic diagram of the structure of the electrode assembly 22 in the embodiments of this application, for example, Figure 15The electrode assembly 22 shown may be a schematic diagram of the electrode assembly 22 included in the battery cell 20 shown in Figures 4 and 5. Figure 16 shows a schematic side view of the electrode assembly 22 of an embodiment of this application, and for example, Figure 16 may be a schematic side view of the electrode assembly 22 shown in Figure 15 perpendicular to the height direction Z of the battery cell 20. Here, for the sake of explanation, the electrode assembly 22 shown in Figures 15 and 16 does not show separators, but separators may be installed between the different electrode plates of this electrode assembly 22.

[0202] As shown in Figures 15 and 16, the electrode assembly 22 of the embodiment of this application may include a first electrode plate 30, and this first electrode plate 30 may be any one of the first electrode plates 30 shown in Figures 6 to 14, and this first electrode plate 30 is configured to be bent at the bending segments 32. Specifically, this first electrode plate 30 includes at least one bending segment 32, and the first electrode plate 30 can be bent at each bending segment 32. For example, the bending direction of the embodiment of this application may include a clockwise direction R1 and / or a counterclockwise direction R2, and this first electrode plate 30 may include a plurality of bending segments 32 with the same or different bending directions. For example, for different types of electrode assemblies 22, the first electrode plate 30 may include bent segments 32 with the same bending direction, and the electrode assembly 22 may be formed after bending in the same direction, or, as shown in Figures 15 to 16, the first electrode plate 30 may include bent segments 32 with different bending directions, and the electrode assembly 22 shown in Figures 15 and 16 may be formed, and the embodiments of this application are not limited thereto.

[0203] In the embodiments of this application, the electrode assembly further includes a plurality of second electrode plates 40 having the opposite polarity to the first electrode plate 30, and these plurality of second electrode plates 40 and the plurality of laminated segments 31 are alternately stacked along the thickness direction T of the laminated segments 31. Specifically, as shown in Figures 15 and 16, taking the first electrode plate 30 as the negative electrode plate as an example, when the first electrode plate 30 is bent, the plurality of laminated segments 31 of the first electrode plate 30 are stacked together along the thickness direction T of the laminated segments 31, that is, stacked along the width direction X of the battery cell 20, and correspondingly, these plurality of second electrode plates 40 can be installed between the plurality of laminated segments 31 by adopting a stacked installation method. In this way, it is not necessary to bend the second electrode plates 40 in the process of bending the electrode assembly 22, reducing the number of layers to be bent and lowering the difficulty of bending the electrode assembly 22.

[0204] In some embodiments, the first electrode plate 30 includes a plurality of bent segments 32, where the bending directions of two of these bent segments 32 at both ends of the same laminated segment 31 are opposite. Specifically, as shown in Figures 15 and 16, the first electrode plate 30 may include a plurality of bent segments 32, where the bending directions of two bent segments 32 connected to both ends of the same laminated segment 31 can be set to be different. For example, the two bent segments 32 can be bent along a clockwise direction R1 and a counterclockwise direction R2, respectively, to form a Z-shaped first electrode plate 30. The bending in different directions forms a laminated electrode assembly 22, which is simple and easy to implement.

[0205] In the embodiments of this application, as shown in Figures 15 and 16, the reinforcing structure 33 may protrude from the surface of the laminated segment 31, and here we take the example that the protrusion direction of the reinforcing structure of the laminated segment 31 is consistent. However, the reinforcing structure 33 may change during subsequent processing of the electrode assembly 22 and during use of the battery cell 20 after assembly.

[0206] For example, this reinforcing structure 33 is an indentation 330 on the surface of the laminated segment 31. Specifically, Figure 17 shows a schematic diagram of the structure of an electrode assembly 22 of an embodiment of the present application. For example, the electrode assembly 22 shown in Figure 17 may be a schematic diagram of the electrode assembly 22 included in the battery cell 20 shown in Figures 4 to 5, and comparing Figure 17 with Figure 15, Figure 17 may be a schematic diagram of the electrode assembly 22 after the reinforcing structure 33 of the electrode assembly 22 shown in Figure 15 has been changed. Figure 18 shows a schematic side view of an electrode assembly 22 of an embodiment of the present application. For example, Figure 18 may be a schematic side view of the electrode assembly 22 shown in Figure 17 perpendicular to the height direction Z of the battery cell 20, and correspondingly, Figure 18 may be a schematic diagram of the electrode assembly 22 after the reinforcing structure 33 of the electrode assembly 22 shown in Figure 16 has been changed. For the sake of explanation, the electrode assembly 22 shown in Figures 17 and 18, similar to Figures 15 and 16, does not show a separator. However, a separator may be installed between the different plates of this electrode assembly 22.

[0207] As shown in Figures 17 and 18, this reinforcing structure 33 may be an indentation 330 on the surface of the laminated segment 31, that is, this reinforcing structure 33 may protrude from the surface of other areas of the laminated segment 31, or it may be flush with the surface of other areas of the laminated segment 31, but an indentation remains on the surface of the laminated segment 31. Thus, this reinforcing structure 33 is the first pole plateDuring the bending process, 30 may be used to restrict the position of the bent segment 32, and thereafter this reinforcing structure 33 is an indentation 330 on the surface of the laminated segment 31, and can improve the space utilization rate of the electrode assembly 22 inside the battery cell 20 without occupying the gaps between the different electrode plate layers of the electrode assembly 22, and further improve the energy density of the battery cell 20.

[0208] It should be understood that the methods by which the reinforcing structure 33 of the embodiment of this application is formed in the indentation 330 may include multiple methods. The following describes variations of the reinforcing structure 33 of the embodiment of this application with reference to the drawings. Figure 19 shows a schematic flowchart of a method 700 for manufacturing an electrode assembly 22 of an embodiment of this application. As shown in Figure 19, this method 700 includes S710 providing a first electrode plate 30 including a laminated segment 31 and a bent segment 32, the bent segment 32 being connected to the laminated segment 31, and a reinforcing structure 33 being installed in the region of the laminated segment 31 close to the bent segment 32, and S720 bending the first electrode plate 30 at the bent segment 32 to form an electrode assembly 22.

[0209] It should be understood that the first electrode plate 30 in this method 700 may be any of the first electrode plates 30 shown in Figures 6 to 14. For example, a reinforcing structure 33 may be installed on this first electrode plate 30. In the process of bending the first electrode plate 30 to form the electrode assembly 22, the bending position of the first electrode plate 30 is limited, so that the first electrode plate 30 is bent at the bending segment 32, the bending misalignment of the first electrode plate 30 can be reduced, wrinkles in the region of the laminated segment 31 close to the bending segment 32 can be reduced, the processing accuracy of the electrode assembly 22 can be improved, and the processing yield and performance of the electrode assembly 22 can be improved. For example, lithium deposition phenomena due to misalignment or wrinkles of the first electrode plate 30 can be reduced, and the reliability of the electrode assembly 22 can be improved.

[0210] Furthermore, the electrode assembly 22 can be formed by bending the bent segment 32, and different types of electrode assemblies 22 can be obtained by different bending methods, and the embodiments of this application are not limited thereto.

[0211] Specifically, as described above, the reinforcing structure 33 of the embodiment of this application can be realized in various ways. For example, the reinforcing structure 33 may be a reinforcing sheet placed on the surface of the first electrode plate 30, and such a reinforcing structure 33 may change during subsequent processing and use of the battery cell 20, with the changes relating to the material of the reinforcing sheet.

[0212] Alternatively, the reinforcing structure 33 can be formed by a method such as pressing. Specifically, this method 700 involves pressing the laminated segment 31 along the thickness direction T of the laminated segment 31 to form a protruding structure on the surface of the laminated segment 31, and the reinforcing structure 33 further includes including this protruding structure and pressing the laminated segment 31 of the electrode assembly 22. The reinforcing structure 33 formed by pressing protrudes from the surface of other areas of the laminated segment 31, and the reinforcing structure 33 protrudes from the first surface 311 of the laminated segment 31 and recesses from the second surface 312 of the laminated segment 31, with the first surface 311 facing the second surface 312. The reinforcing structure 33 formed using this method limits the bending position of the first electrode plate 30 when the first electrode plate 30 is bent, so that the first electrode plate 30 is bent at the bending segment 32, reducing the misalignment of the bending position of the first electrode plate 30 and reducing wrinkles in the region of the laminated segment 31 close to the bending segment 32.

[0213] In some embodiments, the electrode assembly 22 shown in Figures 15 and 16 can be obtained by employing such a reinforcing structure 33 with protrusions. To further reduce the interlayer gap of this electrode assembly 22, the electrode assembly 22 can be pressed to obtain the electrode assembly 22 shown in Figures 17 and 18. After pressing, the size of the reinforcing structure 33 that protrudes from other areas of the laminated segment 31 becomes smaller, and consequently it becomes almost flush with other areas of the laminated segment 31, reducing the distance between the first electrode plate 30 and the second electrode plate 40, further reducing the ion conduction path, and improving the performance of the electrode assembly 22.

[0214] It should be understood that the electrode assembly 22 of the embodiment of this application may be pressed during subsequent processing steps or during subsequent use of the battery cell 20.

[0215] In some embodiments, the laminated segment 31 pressing the electrode assembly 22 of the embodiment of this application is pressed by a hot press. The laminated segment 31 is pressed by a hot press on the electrode assembly 22 shown in Figures 15 and 16 to obtain the electrode assembly 22 shown in Figures 17 and 18.

[0216] In the embodiments of this application, due to the hot-pressing process, the originally protruding reinforcing structure 33 is compressed, further reducing the size of the reinforcing structure 33 that protrudes from other areas of the laminated segment 31, thereby making it nearly flush with other areas of the laminated segment 31, and further becoming an indentation 330 on the surface of the laminated segment 31. Furthermore, the hot-pressing process can further reduce the distance between the first electrode plate 30 and the second electrode plate 40, further reducing the ion conduction path, thereby improving the space utilization rate of the electrode assembly 22 inside the battery cell 20, and further improving the energy density of the battery cell 20.

[0217] It should be understood that because the reinforcing structure 33 protrudes from the surface of the laminated segment 31 before hot pressing, even if the reinforcing structure 33 becomes nearly flush with the other areas after hot pressing, it leaves an indentation 330 or mark on the surface of the laminated segment 31. In particular, when pressing the reinforcing structure 33, the greater the depth of the reinforcing structure 33, the more pronounced the indentation 330 becomes. Furthermore, during use of the battery cell 20, the color of the area with the indentation 330 may differ from the color of the other areas; for example, the color of the indentation 330 may become darker or black.

[0218] In some embodiments, the electrode assembly 22 can be pressed in other ways. For example, during use of the battery cell 20, the electrode assembly 22 may expand, and after expansion, the size of the reinforcing structure 33 protruding from other areas of the laminated segment 31 will also decrease, and it may be pressed so as to be nearly flush with other areas of the laminated segment 31, and further become an indentation 330 on the surface of the laminated segment 31. Specifically, the electrode assembly 22 may not be hot-pressed, or after hot-pressing, the reinforcing structure 33 may still protrude from the surface of other areas of the laminated segment 31, and then during use of the battery cell 20, for example during charging and discharging, the electrode assembly 22 may expand, further reducing the size of the protruding reinforcing structure 33 protruding from other areas of the laminated segment 31, and thus becoming nearly flush with other areas of the laminated segment 31, and further become an indentation 330 on the surface of the laminated segment 31.

[0219] Therefore, in the embodiment of this application, a reinforcing structure 33 is installed in the region of the laminated segment 31 of the first electrode plate 30 that is close to the bent segment 32, thereby increasing the structural strength of the region of the laminated segment 31 that is close to the bent segment 32. Because the strength of the region of the laminated segment 31 that is close to the bent segment 32 is relatively large, the reinforcing structure 33 can determine the position of the bent segment 32, and in the process of bending the first electrode plate 30 to form the electrode assembly 22, the bending position of the first electrode plate 30 is restricted, so that the first electrode plate 30 is bent at the bent segment 32, the misalignment of the bending position of the first electrode plate 30 can be reduced, wrinkles in the region of the laminated segment 31 that is close to the bent segment 32 can be reduced, the processing accuracy of the electrode assembly 22 can be improved, and the processing yield and performance of the electrode assembly 22 can be improved, for example, lithium deposition phenomena due to misalignment or wrinkles of the first electrode plate 30 can be reduced, and the reliability of the electrode assembly 22 can be improved.

[0220] Furthermore, during subsequent processing or use, the reinforcing structure 33 of the electrode assembly 22 can further reduce the distance between the first electrode plate 30 and the second electrode plate 40 without occupying the gap between the different electrode plate layers of the electrode assembly 22, thereby reducing the ion conduction path, improving the space utilization rate of the electrode assembly 22 inside the battery cell 20, and further improving the energy density of the battery cell 20.

[0221] This application has been described with reference to preferred embodiments, but various improvements can be made thereto, and components can be replaced with equivalents, without departing from the scope of this application. In particular, each technical feature referred to in each embodiment may be combined in any way, provided that there is no structural inconsistency. This application is not limited to the specific embodiments disclosed in the specification, but includes all technical ideas that fall within the scope of the claims. [Explanation of Symbols]

[0222] 1 vehicle 10 batteries 11 cabinets 12 Busbar members 20 battery cells 21 Housing 22 Electrode Assembly 30 First electrode, first plate 31 First electrode plate, laminated segment 32. Flexion region, flexion segment 33 Reinforcement structure 40 Second electrode plate 50 Controllers 60 motor 111 Part 1 112 Second part 200 Battery Modules 211 cases 212 Cover Plate 214 Electrode terminal 214a Positive electrode terminal 214b Negative electrode terminal 221 Electrode body 222 tabs 222a Positive Tab 222b Negative Tab 311 First surface 312 Second surface 313 First stacked segment 314 Second stacked segment 330 Indentations 331 Reinforcement structure 332 Reinforcement structure 333 Groove structure

Claims

1. It is a plate, Stacked segment (31), A bending segment (32) connected to the aforementioned laminated segment (31) for bending, Includes, Here, a reinforcing structure (33) is installed in the region of the laminated segment (31) that is close to the bent segment (32), in the electrode plate.

2. The electrode plate according to claim 1, wherein the reinforcing structure (33) includes a protruding structure that protrudes from the surface of the laminated segment (31).

3. The electrode plate according to claim 2, wherein the range of the ratio of the projection height of the projection structure to the thickness of the laminated segment (31) is [0.3, 50], selectively [5, 40], and preferably [8, 20].

4. The projection structure protrudes from the first surface (311) of the laminated segment (31), the projection structure of the laminated segment (31) is recessed from the second surface (312), the first surface (311) is positioned opposite the second surface (312), and / or The electrode plate according to claim 2 or 3, wherein the projection structure includes a reinforcing sheet installed on the surface of the laminated segment (31).

5. The electrode plate according to any one of claims 1 to 4, wherein the range of the ratio of the rigidity of the reinforcing structure (33) to the rigidity of other regions of the laminated segment (31) other than the reinforcing structure (33) is [1.5, 65], selectively [2, 40], preferably [10, 25].

6. The electrode plate according to any one of claims 1 to 5, wherein the range of stiffness values ​​for the reinforcing structure (33) is [10 N / m, 300 N / m], preferably [50 N / m, 150 N / m].

7. The electrode plate according to any one of claims 1 to 6, wherein the reinforcing structure (33) does not pass through the center line of the electrode plate in the longitudinal direction of the laminated segment (31), and the range of the ratio of the span of the reinforcing structure (33) along the longitudinal direction of the electrode plate to the length of the laminated segment (31) is [10%, 50%].

8. The electrode plate according to any one of claims 1 to 6, wherein the range of the ratio between the span of the electrode plate of the reinforcing structure (33) along the longitudinal direction and the length of the laminated segment (31) is [10%, 100%].

9. The electrode plate according to any one of claims 1 to 8, wherein the range of the ratio of the sum of the widths of all the reinforcing structures (33) arranged along the width direction of the electrode plate to the width of the electrode plate is [1 / 3, 0.8], preferably [0.4, 0.6].

10. The electrode plate according to any one of claims 1 to 9, wherein the range of the ratio between the shortest length between the end of the reinforcing structure (33) near the bent segment (32) and the center line of the bent segment (32) and the thickness of the electrode plate is [0.016, 0.5], preferably [0.05, 0.4].

11. The electrode plate according to any one of claims 1 to 10, wherein the reinforcing structure (33) is installed at an inclination with respect to the width direction of the electrode plate.

12. The electrode plate according to claim 11, wherein the range of values ​​for the angle between the reinforcing structure (33) and the electrode plate in the width direction is [45°, 135°].

13. The electrode plate according to any one of claims 1 to 12, wherein a plurality of the reinforcing structures (33) arranged along the width direction of the electrode plate are installed in the region of the laminated segment (31) that is close to the bent segment (32).

14. The electrode plate according to claim 13, wherein the plurality of reinforcing structures (33) are arranged at equal intervals along the width direction of the electrode plate.

15. The electrode plate according to claim 13 or 14, wherein the plurality of reinforcing structures (33) protrude from the surface of the laminated segment (31) and their protrusion directions coincide.

16. The electrode plate according to any one of claims 1 to 15, wherein the electrode plate includes a plurality of laminated segments (31), the bent segment (32) is connected to a first laminated segment (313) and a second laminated segment (314) of the plurality of laminated segments (31), and the reinforcing structure (33) is installed in the region of the first laminated segment (313) close to the bent segment (32) and the region of the second laminated segment (314) close to the bent segment (32).

17. The positions of the reinforcing structure (331) of the first laminated segment (313) and the reinforcing structure (332) of the second laminated segment (314) in the width direction of the electrode plate are installed correspondingly and / or The electrode plate according to claim 16, wherein the reinforcing structure (331) of the first laminated segment (313) and the reinforcing structure (332) of the second laminated segment (314) are installed offset from each other in the width direction of the electrode plate.

18. The electrode plate according to claim 17, wherein the reinforcing structure (331) of the first laminated segment (313) is arranged at equal intervals in the width direction of the electrode plate with respect to the reinforcing structure (332) of the second laminated segment (314).

19. The reinforcing structure (331) of the first laminated segment (313) includes a protruding structure that extends from the surface of the first laminated segment (313), and the reinforcing structure (332) of the second laminated segment (314) includes a protruding structure that extends from the surface of the second laminated segment (314). The electrode plate according to any one of claims 16 to 18, wherein the protruding direction of the reinforcing structure (331) of the first laminated segment (313) is opposite to the protruding direction of the reinforcing structure (332) of the second laminated segment (314).

20. The electrode plate according to any one of claims 1 to 19, wherein the bent segment (32) is provided with a notch (34) extending along the width direction of the electrode plate.

21. The electrode plate according to claim 20, wherein the number of notches (34) includes a plurality, and the reinforcing structure (33) corresponds to a connection region between two adjacent notches (34) among the plurality of notches (34).

22. The electrode plate according to claim 20 or 21, wherein the number of notches (34) includes a plurality of notches (34), each including edge notches (341) located at both ends of the electrode plate along the width direction of the electrode plate and intermediate notches (342) located in the intermediate region of the electrode plate, and the length of the edge notches (341) along the width direction of the electrode plate is greater than the length of the intermediate notches (342) along the width direction of the electrode plate.

23. The electrode plate according to claim 20 or 21, wherein the number of the notches (34) includes a plurality, and the lengths of the plurality of notches (34) are equal along the width direction of the electrode plate.

24. The electrode plate according to any one of claims 20 to 23, wherein the notch (34) is located in the central part of the bent segment (32) along the longitudinal direction of the electrode plate.

25. The electrode plate according to any one of claims 1 to 24, wherein the electrode plate is a negative electrode plate without a negative electrode.

26. An electrode assembly, An electrode assembly comprising a first electrode plate (30), wherein the first electrode plate (30) is the electrode plate according to any one of claims 1 to 25, and the first electrode plate (30) is configured to be bent at the bending segment (32).

27. The electrode assembly according to claim 26, wherein the reinforcing structure (33) is an indentation on the surface of the laminated segment (31).

28. The electrode assembly is The electrode assembly according to claim 26 or 27, further comprising a plurality of second electrodes (40) having opposite polarity to the first electrode (30), wherein the plurality of second electrodes (40) and the plurality of laminated segments (31) are arranged in an alternating stack along the thickness direction of the laminated segments (31).

29. The electrode assembly according to claim 28, wherein the first electrode plate (30) includes a plurality of the bent segments (32), and the bending directions of the two bent segments (32) at both ends of the same laminated segment (31) are opposite.

30. It is a battery cell, A battery cell comprising the electrode assembly according to any one of claims 26 to 29.

31. It is a battery, A battery comprising a plurality of battery cells, each including an electrode assembly according to any one of claims 26 to 29.

32. It is a power-consuming device, A power-consuming device comprising a battery cell according to claim 30, or a battery according to claim 31, wherein the battery cell or the battery is used to provide electrical energy to the power-consuming device.

33. A method for manufacturing an electrode assembly, To provide a first electrode plate (30) including a laminated segment (31) and a bent segment (32), wherein the bent segment (32) is connected to the laminated segment (31), and a reinforcing structure (33) is installed in the region of the laminated segment (31) close to the bent segment (32), The first electrode plate (30) is bent at the aforementioned bent segment (32) to form an electrode assembly, Methods that include...

34. The aforementioned method, The method involves pressing the laminated segment (31) along the thickness direction of the laminated segment (31) to form a protruding structure on the surface of the laminated segment (31), wherein the reinforcing structure (33) includes the protruding structure. Pressing the laminated segment (31) of the electrode assembly, The method according to claim 33, further comprising:

35. Pressing the laminated segment (31) of the electrode assembly as described above is The method according to claim 34, comprising pressing the laminated segment (31) of the electrode assembly by a hot press.

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