Method and device for manufacturing double-sided electrode plate and double-sided electrode plate

Abstract

The invention relates to a double-sided electrode plate manufacturing method and device and a double-sided electrode plate. The method comprises the following steps: respectively placing a mixture in a first multi-roll calendering mechanism and a second multi-roll calendering mechanism, firstly, in the first multi-roll calendering mechanism, carrying out thermal compounding on a first side of a double-sided carbon foil coated current collector and the mixture to form a first active material layer so as to obtain a single-sided electrode plate, and then, carrying out thermal compounding on a second side of the double-sided carbon foil coated current collector and the second multi-roll calendering mechanism so as to obtain a second active material layer; and determining the surface density of the single-sided electrode slice in the process of transferring the single-sided electrode slice to a second multi-roll calendering mechanism through a transmission part, and in the second multi-roll calendering mechanism, performing thermal compounding on the second side of the double-sided carbon foil coated current collector and the mixture to form a second active material layer so as to obtain the double-sided electrode slice, and forming a second active material layer to obtain a double-sided electrode plate, and determining the surface density of the double-sided electrode plate. By adopting the method, the surface density of the active material layers on the two sides of the double-sided electrode plate can be accurately determined while the double-sided electrode plate is manufactured.

Description

Technical Field

[0001] The present application relates to the technical field of electrode sheet manufacturing, and in particular to a double-sided electrode sheet manufacturing method, device and double-sided electrode sheet. Background Art

[0002] In the manufacturing process of lithium-ion batteries, each process step involves many process parameters and performance indicators. These factors jointly determine the performance and quality of the final lithium-ion battery. Among them, the performance of lithium-ion batteries depends to a large extent on the performance of the electrode sheet. In the production process of lithium-ion battery electrode sheets, the subsequent rolling process is usually affected due to problems such as uneven surface density of the active material layer of the electrode sheet and poor thickness consistency, which ultimately affects the overall performance of the lithium-ion battery. Therefore, in actual production, it is particularly important to conduct real-time detection of the surface density of the electrode sheet to ensure the uniformity of the surface density.

[0003] At present, in the existing double-sided electrode sheet manufacturing process, usually only the total surface density of the double-sided electrode sheet can be detected, and the active material layer on any side cannot be detected separately. Obviously, if the surface density of the active material layer on each side of the double-sided electrode sheet cannot be detected separately, the final manufactured double-sided electrode sheet may not meet the design specifications, thereby affecting the performance of the lithium-ion battery cell. Summary of the invention

[0004] Based on this, it is necessary to provide a double-sided electrode sheet manufacturing method, device and double-sided electrode sheet that can accurately determine the surface density of the active material layers on both sides in order to solve the above technical problems.

[0005] In a first aspect, the present application provides a method for manufacturing a double-sided electrode sheet, comprising:

[0006] The mixed material is placed between the roller with the smallest rotation speed and the adjacent roller in the first multi-roller calendering mechanism and the second multi-roller calendering mechanism, respectively, so that the mixed material is calendered and transferred between any two adjacent rollers of the first multi-roller calendering mechanism and the second multi-roller calendering mechanism; the first multi-roller calendering mechanism and the second multi-roller calendering mechanism respectively include at least three rollers arranged in sequence; the first multi-roller calendering mechanism and the second multi-roller calendering mechanism are connected by a transmission component and are arranged on different sides of the transmission component;

[0007] Placing a double-sided carbon-coated foil current collector between the last roller of a first multi-roller calendering mechanism and the first roller adjacent thereto, thermally compounding the double-sided carbon-coated foil current collector and the mixed material so that the mixed material adheres to the first side of the double-sided carbon-coated foil current collector to form a first active material layer to obtain a single-sided electrode sheet;

[0008] Determining the surface density of the first active material layer during the process of transferring the single-sided electrode sheet from the first multi-roller calendering mechanism to the second multi-roller calendering mechanism through the transmission component;

[0009] After the single-sided electrode sheet is transferred to the second multi-roller calendering mechanism through the transmission component, the single-sided electrode sheet and the mixed material are thermally compounded by the last roller of the second multi-roller calendering mechanism and the first roller adjacent thereto, so that the mixed material adheres to the second side of the double-sided carbon-coated foil current collector to form a second active material layer to obtain a double-sided electrode sheet;

[0010] When the second multi-roll calendering mechanism transfers the double-sided electrode sheet to the winding mechanism through the transmission component, the surface density of the double-sided electrode sheet is determined, and the surface density of the second active material layer is determined based on the surface density of the double-sided electrode sheet and the surface density of the first active material layer.

[0011] In a second aspect, the present application also provides a double-sided electrode sheet manufacturing device, comprising:

[0012] A feeding module is used to place the mixed material between the roller with the smallest rotation speed and the adjacent roller in the first multi-roller calendering mechanism and the second multi-roller calendering mechanism, so that the mixed material is calendered and transferred between any two adjacent rollers of the first multi-roller calendering mechanism and the second multi-roller calendering mechanism; the first multi-roller calendering mechanism and the second multi-roller calendering mechanism respectively include at least three rollers arranged in sequence; the first multi-roller calendering mechanism and the second multi-roller calendering mechanism are connected by a transmission component and are arranged on different sides of the transmission component;

[0013] The first forming module is used to place the double-sided carbon-coated foil current collector between the last roller of the first multi-roller calendering mechanism and the adjacent roller, and thermally compound the double-sided carbon-coated foil current collector and the mixed material so that the mixed material adheres to the first side of the double-sided carbon-coated foil current collector to form a first active material layer to obtain a single-sided electrode sheet;

[0014] A first determination module is used to determine the surface density of the first active material layer during the process of transferring the single-sided electrode sheet from the first multi-roller calendering mechanism to the second multi-roller calendering mechanism through the transmission component;

[0015] The second forming module is used for, after the single-sided electrode sheet is transferred to the second multi-roller calendering mechanism through the transmission component, thermally compounding the single-sided electrode sheet and the mixed material through the last roller of the second multi-roller calendering mechanism and the roller adjacent thereto, so that the mixed material adheres to the second side of the double-sided carbon-coated foil current collector to form a second active material layer to obtain a double-sided electrode sheet;

[0016] The second determination module is used to determine the surface density of the double-sided electrode sheet during the process of transferring the double-sided electrode sheet to the winding mechanism through the transmission component of the second multi-roll calendering mechanism, and determine the surface density of the second active material layer based on the surface density of the double-sided electrode sheet and the surface density of the first active material layer.

[0017] In a third aspect, the present application further provides a double-sided electrode sheet, which is manufactured by using part or all of the steps described in any method of the first aspect of the embodiment of the present application.

[0018] The above-mentioned double-sided electrode sheet manufacturing method, device and double-sided electrode sheet, respectively place the mixed material between the roller with the smallest rotation speed in the first multi-roller calendering mechanism and the roller adjacent to it, so that the mixed material is respectively calendered and transferred between any two adjacent rollers of the first multi-roller calendering mechanism and the second multi-roller calendering mechanism; the first multi-roller calendering mechanism and the second multi-roller calendering mechanism respectively include at least three rollers arranged in sequence; the first multi-roller calendering mechanism and the second multi-roller calendering mechanism are connected by a transmission component and are arranged on different sides of the transmission component; the double-sided carbon-coated foil current collector is placed between the last roller of the first multi-roller calendering mechanism and the first roller adjacent to it, and the double-sided carbon-coated foil current collector and the mixed material are thermally compounded, so that the mixed material adheres to the first side of the double-sided carbon-coated foil current collector. The invention relates to a method for forming a first active material layer to obtain a single-sided electrode sheet; in the process of transferring the single-sided electrode sheet to the second multi-roller calendering mechanism through the transmission component of the first multi-roller calendering mechanism, determining the surface density of the first active material layer; after the single-sided electrode sheet is transferred to the second multi-roller calendering mechanism through the transmission component, the single-sided electrode sheet and the mixture are thermally compounded by the last roller of the second multi-roller calendering mechanism and the first roller adjacent to it, so that the mixture adheres to the second side of the double-sided carbon-coated foil current collector to form a second active material layer to obtain a double-sided electrode sheet; in the process of transferring the double-sided electrode sheet to the winding mechanism through the transmission component of the second multi-roller calendering mechanism, determining the surface density of the double-sided electrode sheet, and determining the surface density of the second active material layer based on the surface density of the double-sided electrode sheet and the surface density of the first active material layer. The double-sided electrode sheet manufacturing method provided in the embodiment of the present application is based on two multi-roller calendering mechanisms connected by a transmission component and arranged on different sides of the transmission component, which continuously calender and compound the mixture and the double-sided carbon-coated foil current collector to form a double-sided electrode sheet after two compoundings. Specifically, in the double-sided electrode sheet manufacturing process, the surface density of a new active material layer is detected each time a new active material layer is formed after compounding. Therefore, this embodiment can ensure that the surface density of the active material layers on both sides of the manufactured double-sided electrode sheet is accurately determined, thereby improving the battery performance of the double-sided electrode sheet. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments of the present application or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is a schematic diagram of the structure of a double-sided electrode sheet manufacturing system;

[0021] Figure 2 A schematic diagram of a process for manufacturing a double-sided electrode sheet in one embodiment;

[0022] Figure 3 A schematic diagram of the structure of a double-sided electrode sheet manufacturing system in one embodiment;

[0023] Figure 4 1 is a structural block diagram of a double-sided electrode sheet manufacturing device in one embodiment. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0025] In the electrode sheet manufacturing process, the surface density of the active material layer of the electrode sheet can be obtained by conventional sampling and weighing to perform thickness measurement calculations. However, this conventional sampling and weighing method requires frequent shutdowns during sampling, so it is not suitable for electrode sheet manufacturing production lines that require high-speed operation. At present, the methods that can perform real-time detection of the surface density of the active material layer without stopping mainly include the transmission ray surface density detection method and the ultrasonic surface density detection method.

[0026] The transmitted ray surface density detection method is to detect the surface density of the active material layer of the electrode sheet by transmitted rays. The transmitted rays can be, for example, X-rays, rays or other rays. Specifically, the idea of ​​detecting the surface density of the active material layer of the electrode sheet by transmitted rays is that when the transmitted rays penetrate the electrode sheet, part of the energy of the transmitted rays will be absorbed by the active material layer of the electrode sheet. At this time, there is an attenuation phenomenon in the transmitted rays, and the attenuation intensity is negatively exponentially related to the surface density of the active material layer of the traditional electrode sheet. Therefore, at this time, the ray intensity of the transmitted rays before penetrating the electrode sheet and the ray intensity after penetrating the electrode sheet can be detected to determine the surface density of the active material layer in the electrode sheet based on the two ray intensities.

[0027] The ultrasonic surface density detection method is to detect the surface density of the active material layer of the electrode sheet through ultrasonic waves. Specifically, the idea of ​​detecting the surface density of the active material layer of the electrode sheet through ultrasonic waves is that when the ultrasonic wave penetrates the electrode sheet, part of the sound wave is absorbed by the active material layer of the electrode sheet, resulting in the outgoing sound wave after penetrating the electrode sheet being attenuated in intensity relative to the incident sound wave when it just penetrates the electrode sheet. Since the attenuation ratio of the ultrasonic wave in intensity has a certain functional relationship with the surface density of the active material layer, the surface density of the active material layer can be determined by detecting the attenuation of the sound wave intensity between the incident sound wave and the outgoing sound wave.

[0028] It can be seen that whether the surface density of the active material layer is determined by transmission radiation or ultrasound, it is necessary to ensure that the electrode sheet is between the generator and the sensor of the surface density detector. Figure 1 As shown, there are two multi-roller calendering mechanisms 102, and the calendering directions of the two multi-roller calendering mechanisms 102 are opposite to each other. Each multi-roller calendering mechanism 102 calenders the mixture 104 to obtain a set of dry film sheets, and the double-sided carbon-coated foil current collector 106 is placed between two rollers with the highest rotation speed to thermally compound the dry film sheets and the double-sided carbon-coated foil current collector 106, so that the dry film sheets are compounded on both sides of the double-sided carbon-coated foil current collector 106, and finally a double-sided electrode sheet 108 is obtained. However, in the case of Figure 1 In the double-sided electrode sheet manufacturing system shown, since the active material layers on both sides of the double-sided electrode sheet are formed at the same time, the surface density detector can only detect the total surface density after the double-sided electrode sheet has been compounded, and cannot detect the surface density of either side of the active material layer separately. Obviously, this double-sided electrode sheet manufacturing method cannot detect the surface density of either side of the active material layer separately, which may cause the final manufactured double-sided electrode sheet to fail to meet the design specifications in actual production, thereby affecting the performance of the lithium-ion battery cell.

[0029] Based on this, in an exemplary embodiment, Figure 2 As shown, the present application provides a double-sided electrode sheet manufacturing method, which is described by taking the method applied to a double-sided electrode sheet manufacturing system as an example, and includes the following steps 202 to 210. Among them:

[0030] Step 202, placing the mixed material between the roller with the smallest rotation speed and its adjacent roller in the first multi-roller calendering mechanism and the second multi-roller calendering mechanism, respectively, so that the mixed material is calendered and transferred between any two adjacent rollers of the first multi-roller calendering mechanism and the second multi-roller calendering mechanism; the first multi-roller calendering mechanism and the second multi-roller calendering mechanism respectively include at least three rollers arranged in sequence; the first multi-roller calendering mechanism and the second multi-roller calendering mechanism are connected by a transmission component and are arranged on different sides of the transmission component.

[0031] Among them, the mixture refers to the slurry used to manufacture the double-sided electrode sheet. Optionally, the mixture may include electrode active materials, binders, conductive agents, pore formers and bonding enhancers. Further optionally, in terms of mass percentage, the mixture may include: 75% to 99% electrode active materials, 0.5% to 10% binders, 0.5% to 10% conductive agents, 0 to 3% pore formers and 0 to 5% bonding enhancers.

[0032] Specifically, the mixed material is in the form of a film after being rolled by the rollers. It is easy to understand that the mixed material in the form of a film can be called a dry film.

[0033] Optionally, the roller with the smallest rotation speed may be the first roller along the calendering direction in the first multi-roller calendering mechanism and the second multi-roller calendering mechanism.

[0034] Specifically, the rolling direction of the first multi-roll rolling mechanism and the rolling direction of the second multi-roll rolling mechanism are opposite to each other. That is to say, with the horizontal line as the reference, the rolling direction of the first multi-roll rolling mechanism and the rolling direction of the second multi-roll rolling mechanism are opposite. Exemplarily, with the horizontal line as the reference, assuming that the rolling direction of the first multi-roll rolling mechanism is to roll from left to right along the horizontal line, then the rolling direction of the second multi-roll rolling mechanism is to roll from right to left along the horizontal line.

[0035] Optionally, in the first multi-roller calendering mechanism and the second multi-roller calendering mechanism, the mixed material may be calendered 2 to 10 times respectively. Further, when the mixed material is calendered 2 to 10 times, the number of rollers in the first multi-roller calendering mechanism and the number of rollers in the second multi-roller calendering mechanism may correspond to 3 to 11 respectively.

[0036] Specifically, the speed ratio of any two adjacent rollers along the calendering direction is less than 1, so that, in the first multi-roller calendering mechanism and the second multi-roller calendering mechanism, the rotation speed of the latter roller along the calendering direction is faster than that of the former roller, that is, the rotation speeds of the rollers arranged in sequence along the calendering direction are increased in sequence. Optionally, the speed ratio of any two adjacent rollers along the calendering direction can be 0.95, 0.5, 0.25 or other values; further, optionally, the speed ratios of two adjacent rollers in different groups along the calendering direction can be different, as long as the rotation speed of the latter roller is faster than that of the former roller, so as to ensure that the dry film formed by the calendering of the mixed material can be transferred and adhered to the roller with a faster rotation speed.

[0037] In an exemplary embodiment, the speed ratio of any two adjacent rollers along the calendering direction is 1:(1.05-4).

[0038] Among them, the transmission component is used to continuously and smoothly transfer the single-sided electrode sheet formed by the first compounding in the first multi-roller calendering mechanism from the first multi-roller calendering mechanism to the second multi-roller calendering mechanism, so that the single-sided electrode sheet is compounded for the second time in the second multi-roller calendering mechanism to form a double-sided electrode sheet.

[0039] It should be noted that the transmission component can also maintain the tension of the single-sided electrode sheet during the process of transmitting the single-sided electrode sheet from the first multi-roller calendering mechanism to the second multi-roller calendering mechanism, so the transmission component can be a component having both a transmission function and a tension maintenance function. Exemplarily, the transmission component can be a conveyor belt with a tension control function or a guide roller.

[0040] Specifically, the first multi-roller calendering mechanism and the second multi-roller calendering mechanism are connected by a transmission component and are arranged on different sides of the transmission component, which means that the first multi-roller calendering mechanism and the second multi-roller calendering mechanism are respectively located at the two side end points or two side positions of the transmission component.

[0041] Step 204, placing the double-sided carbon coated foil current collector between the last roller of the first multi-roller calendering mechanism and the first roller adjacent thereto, thermally compounding the double-sided carbon coated foil current collector and the mixture so that the mixture adheres to the first side of the double-sided carbon coated foil current collector to form a first active material layer to obtain a single-sided electrode sheet.

[0042] The double-sided carbon-coated foil current collector comprises two carbon-coated layers and a current collector base foil, wherein the two carbon-coated layers are respectively located on both sides of the current collector base foil. Optionally, the carbon-coated layers may be composed of at least one of carbon black, graphite, carbon fiber, and carbon nanotubes.

[0043] The last roller of the first multi-roller calendering mechanism is the last roller of the first multi-roller calendering mechanism along the calendering direction. It is easy to understand that the first roller adjacent to the last roller of the first multi-roller calendering mechanism is the second to last roller of the first multi-roller calendering mechanism along the calendering direction.

[0044] The active material layer refers to the material in the electrode sheet that can participate in the redox reaction during the charge and discharge process of the battery, thereby realizing the conversion between electrical energy and chemical energy. Specifically, the first active material layer refers to the active material layer adhered to the first side of the double-sided carbon-coated foil current collector.

[0045] Specifically, the double-sided carbon-coated foil current collector is placed between the last roller of the first multi-roller calendering mechanism and the first roller adjacent thereto through the unwinding mechanism.

[0046] Specifically, in order to achieve thermal compounding of the double-sided carbon-coated foil current collector and the mixed material between the last roller of the first multi-roller calendering mechanism and its adjacent first roller, one roller needs to be a cold roller and the other roller needs to be a hot roller between the last roller and the first roller.

[0047] In an exemplary embodiment, in the first multi-roll calendering mechanism and the second multi-roll calendering mechanism, the last roller is a cold roller and the first roller is a hot roller.

[0048] The hot roller is used to heat one side of the double-sided carbon-coated foil current collector to exert the thermal viscosity of the carbon-coated layer on one side of the double-sided carbon-coated foil current collector, so that the mixture after calendering can adhere to the first side of the double-sided carbon-coated foil current collector to form a first active material layer to obtain a single-sided electrode sheet. Optionally, the temperature of the hot roller can be 50~250℃.

[0049] Specifically, the last roller is a cold roller, which can ensure that the second side of the double-sided carbon-coated foil current collector will not develop thermal viscosity due to heating. Therefore, by preventing the second side of the double-sided carbon-coated foil current collector from adhering to the last roller, on the one hand, it can avoid the phenomenon of missing or damaged carbon coating layer, thereby ensuring the integrity and stability of the double-sided carbon-coated foil current collector. On the other hand, it also ensures that the single-sided electrode sheet can be smoothly transferred from the first multi-roller calendering mechanism to the second multi-roller calendering mechanism through the transmission component.

[0050] Specifically, the last roller of the first multi-roller calendering mechanism and the last roller of the second multi-roller calendering mechanism are both cold rollers, and the first roller of the first multi-roller calendering mechanism and the first roller of the second multi-roller calendering mechanism are both hot rollers.

[0051] It is easy to understand that since the last roller of the first multi-roller calendering mechanism and the first roller adjacent thereto are used to thermally compound the double-sided carbon-coated foil current collector and the mixed material to obtain a single-sided electrode sheet, the last roller of the first multi-roller calendering mechanism and the first roller adjacent thereto are called a compound roller pair. Similarly, the last roller of the second multi-roller calendering mechanism and the first roller adjacent thereto are also called a compound roller pair.

[0052] Step 206 , in the process of transferring the single-sided electrode sheet from the first multi-roller calendering mechanism to the second multi-roller calendering mechanism through the transmission component, determining the surface density of the first active material layer.

[0053] The surface density of the first active material layer can be determined by transmission radiation or ultrasound. Optionally, the transmission radiation can be X-rays, β-rays or other rays. Specifically, the surface density of the first active material layer is determined by real-time detection.

[0054] Specifically, when the transmitted ray penetrates the single-sided electrode sheet, part of its energy will be absorbed by the first active material layer of the single-sided electrode sheet. Since the energy attenuation degree of the transmitted ray is in a negative exponential relationship with the surface density of the first active material layer, the surface density of the first active material layer in the single-sided electrode sheet can be determined by detecting the first ray intensity before the transmitted ray penetrates the single-sided electrode sheet and the second ray intensity after the transmitted ray penetrates the single-sided electrode sheet. The surface density of the first active material layer in the single-sided electrode sheet can be determined by calculation based on the first ray intensity and the second ray intensity. Thus, the surface density of the first active material layer can be determined by the transmitted ray.

[0055] Specifically, when the ultrasonic wave penetrates the single-sided electrode sheet, part of the sound wave will be absorbed by the first active material layer of the single-sided electrode sheet, resulting in the outgoing sound wave after penetrating the single-sided electrode sheet being attenuated in intensity relative to the incident sound wave just penetrating the single-sided electrode sheet. Since the attenuation ratio of the ultrasonic wave in intensity has a certain functional relationship with the surface density of the active material layer, the surface density of the first active material layer can be determined by detecting the attenuation of the sound wave intensity between the incident sound wave and the outgoing sound wave. At this point, the surface density of the first active material layer is determined by ultrasonic wave.

[0056] Optionally, a first surface density detector may be provided between the first multi-roll calendering mechanism and the second multi-roll calendering mechanism to determine the surface density of the first active material layer. The first surface density detector may be a transmission ray surface density detector that determines the surface density of the first active material layer by transmission rays, or may be an ultrasonic surface density detector that determines the surface density of the first active material layer by ultrasonic waves.

[0057] Step 208, after the single-sided electrode sheet is transferred to the second multi-roller rolling mechanism through the transmission component, the single-sided electrode sheet and the mixture are thermally compounded by the last roller of the second multi-roller rolling mechanism and the first roller adjacent to it, so that the mixture adheres to the second side of the double-sided carbon-coated foil current collector to form a second active material layer to obtain a double-sided electrode sheet.

[0058] The last roller of the second multi-roller calendering mechanism is the last roller of the second multi-roller calendering mechanism along the calendering direction. It is easy to understand that the first roller adjacent to the last roller of the second multi-roller calendering mechanism is the second to last roller of the second multi-roller calendering mechanism along the calendering direction.

[0059] Specifically, since the rolling direction of the first multi-roller rolling mechanism and the rolling direction of the second multi-roller rolling mechanism are in opposite directions, among the multiple rollers of the first multi-roller rolling mechanism and the multiple rollers of the second multi-roller rolling mechanism, there is a minimum distance between the last roller of the first multi-roller rolling mechanism and the last roller of the second multi-roller rolling mechanism.

[0060] The second active material layer refers to the active material layer adhered to the second side of the double-sided carbon-coated foil current collector.

[0061] It is easy to understand that the single-sided electrode sheet includes a double-sided carbon-coated foil current collector and a first active material layer adhered to the first side of the double-sided carbon-coated foil current collector. Therefore, specifically, the second side of the double-sided carbon-coated foil current collector in the single-sided electrode sheet and the mixed material are thermally compounded by the last roller of the second multi-roller rolling mechanism and the first roller adjacent thereto, so that the mixed material adheres to the second side of the double-sided carbon-coated foil current collector to form a second active material layer to obtain a double-sided electrode sheet.

[0062] Step 210, during the process of the second multi-roll calendering mechanism transferring the double-sided electrode sheet to the winding mechanism through the transmission component, the surface density of the double-sided electrode sheet is determined, and based on the surface density of the double-sided electrode sheet and the surface density of the first active material layer, the surface density of the second active material layer is determined.

[0063] Among them, the winding mechanism is used to wind up the double-sided electrode sheet.

[0064] Similarly, the surface density of the double-sided electrode sheet can also be determined by transmission rays or ultrasound. Specifically, the surface density of the double-sided electrode sheet is determined by real-time detection.

[0065] Specifically, the idea of ​​determining the surface density of the second active material layer by transmitted rays and ultrasound is the same as the idea of ​​determining the surface density of the second active material layer by transmitted rays and ultrasound, so how to determine the surface density of the second active material layer by transmitted rays and ultrasound will not be repeated here.

[0066] Optionally, a second surface density detector may be provided between the second multi-roll calendering mechanism and the winding mechanism to determine the surface density of the double-sided electrode sheet. The second surface density detector may be a transmission ray surface density detector that determines the surface density of the double-sided electrode sheet by transmission ray, or may be an ultrasonic surface density detector that determines the surface density of the double-sided electrode sheet by ultrasonic wave.

[0067] It is easy to understand that the surface density of the double-sided electrode sheet is determined based on the surface density of the first active material layer and the surface density of the second active material layer. Therefore, in order to determine the surface density of the second active material layer, it is necessary to first determine the surface density of the first active material layer and the surface density of the double-sided electrode sheet. Based on this, the present embodiment divides the thermal composite process into two times to realize two surface density detection processes. The first thermal composite occurs in the first multi-roller calendering mechanism to form a single-sided electrode sheet, and the second thermal composite occurs in the second multi-roller calendering mechanism so that the second side of the double-sided carbon-coated foil current collector in the single-sided electrode sheet forms a second active material layer to form a double-sided electrode sheet. Only by respectively determining the surface density of the first active material layer and the surface density of the double-sided electrode sheet, it is finally possible to respectively determine the surface density of the first active material layer and the surface density of the second active material layer located on both sides of the double-sided carbon-coated foil current collector.

[0068] For example, this embodiment is applied to Figure 3In the double-sided electrode sheet manufacturing system shown in the figure, the mixture 302 is placed between the roller with the smallest rotation speed in the first multi-roller calendering mechanism 304 and the roller adjacent to it, so that the mixture 302 is calendered and transferred between any two adjacent rollers of the first multi-roller calendering mechanism 304 and the second multi-roller calendering mechanism 306; the first multi-roller calendering mechanism 304 and the second multi-roller calendering mechanism 306 respectively include at least three rollers arranged in sequence; the first multi-roller calendering mechanism 304 and the second multi-roller calendering mechanism 306 are connected by a transmission component and are arranged on different sides of the transmission component; the double-sided carbon-coated foil current collector 310 is placed between the last roller 312 of the first multi-roller calendering mechanism 304 and the first roller 314 adjacent to it by the unwinding mechanism 308, and the double-sided carbon-coated foil current collector 310 and the mixture 302 are thermally compounded, so that the mixture 302 adheres to the first side of the double-sided carbon-coated foil current collector 310 to form a first active material layer to obtain a single-sided electrode Pole sheet 316; in the process of transferring the single-sided electrode sheet 316 to the second multi-roller calendering mechanism 306 through the transmission component of the first multi-roller calendering mechanism 304, the surface density of the first active material layer is determined by the first surface density detector 318; after the single-sided electrode sheet 316 is transferred to the second multi-roller calendering mechanism 306 through the transmission component, the single-sided electrode 316 sheet and the mixed material 302 are thermally compounded by the last roller 320 of the second multi-roller calendering mechanism 306 and the first roller 322 adjacent to it, so that the mixed material 302 adheres to the second side of the double-sided carbon-coated foil current collector 310 to form a second active material layer to obtain a double-sided electrode sheet 324; in the process of transferring the double-sided electrode sheet 324 to the winding mechanism 326 through the transmission component of the second multi-roller calendering mechanism 306, the surface density of the double-sided electrode sheet 324 is determined by the second surface density detector 328, and the surface density of the second active material layer is determined based on the surface density of the double-sided electrode sheet 324 and the surface density of the first active material layer.

[0069] In this embodiment, since the manufacturing process of the double-sided electrode sheet needs to undergo two thermal composites successively, the surface density of the first active material layer and the surface density of the second active material layer can be detected in real time respectively. At the same time, since the active material layers on different sides are obtained in different multi-roller calendering mechanisms, this embodiment can also realize separate composite pressure control for the two thermal composites. It is easy to understand that in order to increase the compaction density of the active material layer, a larger composite pressure is usually used. Since this embodiment can separately control the rolling pressure of the composite roller pair of the first multi-roller calendering mechanism and the second multi-roller calendering mechanism, that is, the composite pressure, there is no doubt that this embodiment can provide great help for the double-sided electrode sheet manufacturing scenario whether it is desired to regulate the compaction density of the active material layers on different sides or to increase the compaction density of the active material layers on different sides.

[0070] In the above-mentioned double-sided electrode sheet manufacturing method, the mixed material is placed between the roller with the smallest rotation speed in the first multi-roller calendering mechanism and the roller adjacent to it, so that the mixed material is calendered and transferred between any two adjacent rollers of the first multi-roller calendering mechanism and the second multi-roller calendering mechanism; the first multi-roller calendering mechanism and the second multi-roller calendering mechanism respectively include at least three rollers arranged in sequence; the first multi-roller calendering mechanism and the second multi-roller calendering mechanism are connected by a transmission component and are arranged on different sides of the transmission component; the double-sided carbon-coated foil current collector is placed between the last roller of the first multi-roller calendering mechanism and the first roller adjacent to it, and the double-sided carbon-coated foil current collector and the mixed material are thermally compounded, so that the mixed material adheres to the first side of the double-sided carbon-coated foil current collector to form a first active a first active material layer to obtain a single-sided electrode sheet; in the process of transferring the single-sided electrode sheet from the first multi-roller calendering mechanism to the second multi-roller calendering mechanism through the transmission component, determining the surface density of the first active material layer; after the single-sided electrode sheet is transferred to the second multi-roller calendering mechanism through the transmission component, the single-sided electrode sheet and the mixture are thermally compounded by the last roller of the second multi-roller calendering mechanism and the first roller adjacent to it, so that the mixture adheres to the second side of the double-sided carbon-coated foil current collector to form a second active material layer to obtain a double-sided electrode sheet; in the process of transferring the double-sided electrode sheet from the second multi-roller calendering mechanism to the winding mechanism through the transmission component, determining the surface density of the double-sided electrode sheet, and determining the surface density of the second active material layer based on the surface density of the double-sided electrode sheet and the surface density of the first active material layer. The double-sided electrode sheet manufacturing method provided in the embodiment of the present application is based on two multi-roller calendering mechanisms connected by a transmission component and arranged on different sides of the transmission component, which continuously calender and compound the mixture and the double-sided carbon-coated foil current collector to form a double-sided electrode sheet after two compoundings. Specifically, in the double-sided electrode sheet manufacturing process, the surface density of a new active material layer is detected each time a new active material layer is formed after compounding. Therefore, this embodiment can ensure that the surface density of the active material layers on both sides of the manufactured double-sided electrode sheet is accurately determined, thereby improving the battery performance of the double-sided electrode sheet.

[0071] It should be noted that since the double-sided electrode sheet manufacturing method provided in the embodiment of the present application does not use any solvent, the double-sided electrode sheet manufacturing method provided in the embodiment of the present application is a dry double-sided electrode sheet manufacturing method, and the electrode sheet obtained by the double-sided electrode sheet manufacturing method provided in the embodiment of the present application does not contain any solvent.

[0072] In an exemplary embodiment, the determining of the surface density of the second active material layer based on the surface density of the double-sided electrode sheet and the surface density of the first active material layer includes:

[0073] The density difference between the areal density of the double-sided electrode sheet and the areal density of the first active material layer is determined as the areal density of the second active material layer.

[0074] Among them, the density difference between the surface density of the double-sided electrode sheet and the surface density of the first active material layer, that is, the difference between the surface density of the double-sided electrode sheet and the surface density of the first active material layer, that is, the surface density of the second active material layer = the surface density of the double-sided electrode sheet - the surface density of the first active material layer.

[0075] Specifically, since the mixture is continuously placed in the first multi-roller calendering mechanism and the second multi-roller calendering mechanism, and the first multi-roller calendering mechanism and the second multi-roller calendering mechanism are continuously calendering and transferring the mixture, the surface density of the first active material layer and the surface density of the double-sided electrode sheet are also continuously detected, and thus, it is easy to understand that the surface density of the first active material layer and the surface density of the double-sided electrode sheet obtained in this embodiment are both detected in real time, and further, the surface density of the second active material layer is also determined in real time. Therefore, the surface density of the active material layers on both sides of the double-sided electrode sheet manufactured in this embodiment is real-time.

[0076] In this embodiment, since the surface density of the double-sided electrode sheet is determined by the surface density of the first active material layer and the surface density of the second active material layer, the surface density of the second active material layer can be determined by deducting the surface density of the first active material layer from the surface density of the double-sided electrode sheet. Since the surface density of the first active material layer and the surface density of the double-sided electrode sheet are both detected in real time, this embodiment can ensure that the surface density of the active material layers on both sides of the manufactured double-sided electrode sheet is real-time and accurate.

[0077] In an exemplary embodiment, in the first multi-roller calendering mechanism and the second multi-roller calendering mechanism, the diameter of the last roller and the diameter of the first roller are greater than the diameter of the second roller, and the second roller is a roller other than the last roller and the first roller, and the second roller is used to calender the mixture into a film shape.

[0078] Among them, the second roller is only used to roll the mixture into a film shape, and is not used to thermally composite the double-sided carbon-coated foil current collector and the mixture. Therefore, any two second rollers are not a composite roller pair, and any two second rollers can be called a film-forming roller pair.

[0079] In an exemplary embodiment, the diameter of the final roller and the diameter of the first roller adjacent to the final roller are 500-1200 mm, and the diameter of the second roller is 100-700 mm.

[0080] In the present embodiment, in the first multi-roller calendering mechanism and the second multi-roller calendering mechanism, the diameter of the last roller and the diameter of the first roller are larger than the diameter of the second roller. Since the double-sided carbon-coated foil current collector and the mixture are thermally compounded between the last roller and the first roller, on the one hand, the rolling pressure between the last roller and the first roller can be increased based on the larger diameter of the last roller and the first roller, and the compaction pressure between the double-sided carbon-coated foil current collector and the mixture can be increased based on the larger rolling pressure, thereby obtaining a double-sided electrode sheet with a higher compaction density; on the other hand, the last roller and the first roller with a larger diameter have a larger contact area with the double-layer carbon-coated foil current collector, thereby applying a rolling pressure with a more uniform pressure distribution to the double-layer carbon-coated foil current collector, thereby making it less likely for the double-layer carbon-coated foil current collector subjected to a larger rolling pressure to warp, wrinkle, or other undesirable phenomena. Therefore, in this embodiment, the greater rolling pressure brought by the composite roller pair with a larger diameter can increase the compaction density of the active material layers on both sides of the double-sided electrode sheet while ensuring that the appearance of the double-sided electrode sheet has a high degree of flatness.

[0081] In an exemplary embodiment, in the first multi-roller calendering mechanism and the second multi-roller calendering mechanism, the rolling pressure between the last roller and the first roller is greater than the rolling pressure between any other two adjacent rollers.

[0082] Among them, in the first multi-roller calendering mechanism and the second multi-roller calendering mechanism, the other rollers except the last roller and the first roller are second rollers for calendering the mixture into a film shape, so that, in the first multi-roller calendering mechanism and the second multi-roller calendering mechanism, the rolling pressure between the last roller and the first roller is greater than the rolling pressure between any two second rollers and the rolling pressure between the first roller and the second roller.

[0083] In the present embodiment, the first roller in the first multi-roller calendering mechanism and the first roller in the second multi-roller calendering mechanism are respectively the fixed roller in the first multiple calendering mechanisms and the fixed roller in the second multi-roller calendering mechanism. Thus, by respectively regulating the distance between the fixed roller and the last roller and the second roller, the rolling pressure on both sides of the fixed roller can be respectively regulated. Furthermore, on the one hand, the rolling pressure distribution of the first multi-roller calendering mechanism and the second multi-roller calendering mechanism is improved by the setting of the fixed roller. On the other hand, the rolling pressure of the last roller and the first roller, that is, the composite roller pair, can also be improved, so that the rolling pressure of the composite roller pair is greater than the rolling pressure of the film-forming roller pair. It is easy to understand that based on the greater composite pressure of the composite roller pair, the compaction density of the active material layers on both sides can be increased to improve the battery performance of the double-sided electrode sheet finally obtained.

[0084] It should be noted that in the existing double-sided electrode sheet manufacturing technology, in order to improve the compaction density of the active material layers on different sides, the rolling pressure between different rollers in the multi-roller calendering mechanism is usually increased as much as possible. However, if the rolling pressure in the multi-roller calendering mechanism is too large, it will correspondingly bring great bearing pressure to the hydraulic performance of the entire multi-roller calendering mechanism. In this embodiment, by setting the first roller as a fixed roller in the first multiple calendering mechanisms and the second multi-roller calendering mechanism respectively, the rolling pressure of the film-forming roller pair can be appropriately reduced by increasing the rolling pressure of the composite roller pair, thereby achieving a reasonable configuration of the rolling pressure, which ensures the safety of the multi-roller calendering mechanism while also improving the compaction density of the active material layers on different sides of the manufactured double-sided electrode sheet.

[0085] In an exemplary embodiment, the method further includes: adjusting the rolling pressure between the last roller in the first multi-roller calendering mechanism and the first roller adjacent to it based on the surface density of the first active material layer; and adjusting the rolling pressure between the last roller in the second multi-roller calendering mechanism and the first roller adjacent to it based on the surface density of the second active material layer.

[0086] Exemplarily, the surface density of the first active material layer and the rolling pressure between the last roller in the first multi-roller calendering mechanism and the first roller adjacent thereto may be positively correlated. Thus, when the surface density of the first active material layer is less than the first preset surface density, the rolling pressure between the last roller in the first multi-roller calendering mechanism and the first roller adjacent thereto is increased.

[0087] Exemplarily, the surface density of the second active material layer and the rolling pressure between the last roller in the second multi-roller calendering mechanism and the second roller adjacent thereto may be positively correlated. Thus, when the surface density of the second active material layer is less than the second preset surface density, the rolling pressure between the last roller in the second multi-roller calendering mechanism and the second roller adjacent thereto is increased.

[0088] In this embodiment, since the surface density of the first active material layer and the surface density of the second active material layer are detected in real time, when the surface density of the first active material layer or the surface density of the second active material layer does not meet the expected requirements, the rolling pressure of the composite roller pairs in different multi-roller calendering mechanisms can be adjusted based on the actual surface density of different active material layers, thereby improving the control flexibility of the manufacturing process of the double-sided electrode sheet.

[0089] In an exemplary embodiment, in the process of transferring the single-sided electrode sheet to the second multi-roller calendering mechanism through the transmission component by the first multi-roller calendering mechanism, determining the surface density of the first active material layer includes:

[0090] In the process of transferring the single-sided electrode sheet to the second multi-roller calendering mechanism through the transmission component, the surface density of the first active material layer is determined by a first surface density detector.

[0091] In the process of transferring the double-sided electrode sheet to the winding mechanism through the transmission component by the second multi-roller calendering mechanism, determining the surface density of the double-sided electrode sheet includes:

[0092] In the process of transferring the double-sided electrode sheet to the winding mechanism through the transmission component, the surface density of the double-sided electrode sheet is determined by a second surface density detector.

[0093] Wherein, the first surface density detector and the second surface density detector respectively include a transmission ray surface density detector or an ultrasonic surface density detector.

[0094] Specifically, the first surface density detector is arranged between the first multi-roller calendering mechanism and the second multi-roller calendering mechanism, and the second surface density detector is arranged between the second multi-roller calendering mechanism and the winding mechanism.

[0095] Optionally, the first surface density detector and the second surface density detector respectively include a transmitted ray surface density detector or an ultrasonic surface density detector, which may include: the case where the first surface density detector is a transmitted ray surface density detector and the second surface density detector is a transmitted ray surface density detector, the case where the first surface density detector is a transmitted ray surface density detector and the second surface density detector is an ultrasonic surface density detector, the case where the first surface density detector is an ultrasonic surface density detector and the second surface density detector is a transmitted ray surface density detector, and the case where the first surface density detector is an ultrasonic surface density detector and the second surface density detector is an ultrasonic surface density detector, that is, a total of four cases may be included.

[0096] In the present embodiment, by respectively arranging the first surface density detector and the second surface density detector between the first multi-roller calendering mechanism and the second multi-roller calendering mechanism and between the second multi-roller calendering mechanism and the winding mechanism, during the manufacturing process of the double-sided electrode sheet, the surface density of a new active material layer will be detected each time it is formed after compounding. Therefore, the present embodiment can ensure that the surface density of the active material layers on both sides of the manufactured double-sided electrode sheet is accurately determined, thereby improving the battery performance of the double-sided electrode sheet.

[0097] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0098] Based on the same inventive concept, the embodiment of the present application also provides a double-sided electrode sheet manufacturing device for implementing the double-sided electrode sheet manufacturing method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more double-sided electrode sheet manufacturing device embodiments provided below can refer to the limitations of the double-sided electrode sheet manufacturing method above, and will not be repeated here.

[0099] In an exemplary embodiment, Figure 4 As shown, a double-sided electrode sheet manufacturing device is provided, including: a feeding module 402, a first forming module 404, a first determining module 406, a second forming module 408 and a second determining module 410, wherein:

[0100] The feeding module 402 is used to place the mixed material between the roller with the smallest rotation speed and the adjacent roller in the first multi-roller calendering mechanism and the second multi-roller calendering mechanism, so that the mixed material is calendered and transferred between any two adjacent rollers of the first multi-roller calendering mechanism and the second multi-roller calendering mechanism; the first multi-roller calendering mechanism and the second multi-roller calendering mechanism respectively include at least three rollers arranged in sequence; the first multi-roller calendering mechanism and the second multi-roller calendering mechanism are connected by a transmission component and are arranged on different sides of the transmission component;

[0101] The first forming module 404 is used to place the double-sided carbon-coated foil current collector between the last roller of the first multi-roller calendering mechanism and its adjacent roller, and perform thermal compounding on the double-sided carbon-coated foil current collector and the mixed material so that the mixed material adheres to the first side of the double-sided carbon-coated foil current collector to form a first active material layer to obtain a single-sided electrode sheet;

[0102] A first determination module 406 is used to determine the surface density of the first active material layer during the process of transferring the single-sided electrode sheet from the first multi-roller calendering mechanism to the second multi-roller calendering mechanism through the transmission component;

[0103] The second forming module 408 is used to heat-reinforce the single-sided electrode sheet and the mixed material through the last roller of the second multi-roller rolling mechanism and the rollers adjacent thereto after the single-sided electrode sheet is transferred to the second multi-roller rolling mechanism through the transmission component, so that the mixed material adheres to the second side of the double-sided carbon-coated foil current collector to form a second active material layer to obtain a double-sided electrode sheet;

[0104] The second determination module 410 is used to determine the surface density of the double-sided electrode sheet during the process of transferring the double-sided electrode sheet to the winding mechanism through the transmission component of the second multi-roller calendering mechanism, and determine the surface density of the second active material layer based on the surface density of the double-sided electrode sheet and the surface density of the first active material layer.

[0105] In an exemplary embodiment, the second determination module 410 is further configured to determine the density difference between the surface density of the double-sided electrode sheet and the surface density of the first active material layer as the surface density of the second active material layer.

[0106] In an exemplary embodiment, in the first multi-roller calendering mechanism and the second multi-roller calendering mechanism of the double-sided electrode sheet manufacturing device, the last roller is a cold roller and the first roller is a hot roller.

[0107] In an exemplary embodiment, in the first multi-roller calendering mechanism and the second multi-roller calendering mechanism of the above-mentioned double-sided electrode sheet manufacturing device, the diameter of the last roller and the diameter of the first roller are greater than the diameter of the second roller, and the second roller is a roller other than the last roller and the first roller, and the second roller is used to calender the mixture into a film shape.

[0108] In an exemplary embodiment, the diameter of the last roller of the double-sided electrode sheet manufacturing device and the diameter of the first roller adjacent to the last roller are 500-1200 mm, and the diameter of the second roller is 100-700 mm.

[0109] In an exemplary embodiment, in the first multi-roller calendering mechanism and the second multi-roller calendering mechanism of the double-sided electrode sheet manufacturing device, the rolling pressure between the last roller and the first roller is greater than the rolling pressure between any other two adjacent rollers.

[0110] In an exemplary embodiment, the first determination module 406 is also used to determine the surface density of the first active material layer by a first surface density detector during the process of transferring the single-sided electrode sheet to the second multi-roller calendering mechanism through the transmission component. The second determination module 410 is also used to determine the surface density of the double-sided electrode sheet by a second surface density detector during the process of transferring the double-sided electrode sheet to the winding mechanism through the transmission component. The first surface density detector and the second surface density detector respectively include a transmission ray surface density detector or an ultrasonic surface density detector.

[0111] In an exemplary embodiment, the speed ratio of any two adjacent rollers of the double-sided electrode sheet manufacturing device along the calendering direction is 1: (1.05-4).

[0112] Each module in the above-mentioned double-sided electrode sheet manufacturing device can be fully or partially implemented by software, hardware and their combination. The above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the corresponding operations of the above modules.

[0113] In an exemplary embodiment, a double-sided electrode sheet is further provided. The double-sided electrode sheet is manufactured using the steps in the above method embodiments.

[0114] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0115] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for manufacturing a double-sided electrode sheet, characterized in that: The method comprises: The mixed material is placed between the roller with the smallest rotation speed and the adjacent roller in the first multi-roller calendering mechanism and the second multi-roller calendering mechanism, respectively, so that the mixed material is calendered and transferred between any two adjacent rollers of the first multi-roller calendering mechanism and the second multi-roller calendering mechanism; the first multi-roller calendering mechanism and the second multi-roller calendering mechanism respectively include at least three rollers arranged in sequence; the first multi-roller calendering mechanism and the second multi-roller calendering mechanism are connected by a transmission component and are arranged on different sides of the transmission component; Placing a double-sided carbon-coated foil current collector between the last roller of the first multi-roller calendering mechanism and the first roller adjacent thereto, thermally compounding the double-sided carbon-coated foil current collector and the mixed material so that the mixed material adheres to the first side of the double-sided carbon-coated foil current collector to form a first active material layer to obtain a single-sided electrode sheet; determining the surface density of the first active material layer during the process in which the first multi-roller calendering mechanism transfers the single-sided electrode sheet to the second multi-roller calendering mechanism through the transmission component; After the single-sided electrode sheet is transferred to the second multi-roller calendering mechanism through the transmission component, the single-sided electrode sheet and the mixed material are thermally compounded by the last roller of the second multi-roller calendering mechanism and the first roller adjacent thereto, so that the mixed material adheres to the second side of the double-sided carbon-coated foil current collector to form a second active material layer to obtain a double-sided electrode sheet; During the process of the second multi-roll calendering mechanism transferring the double-sided electrode sheet to the winding mechanism through the transmission component, the surface density of the double-sided electrode sheet is determined, and based on the surface density of the double-sided electrode sheet and the surface density of the first active material layer, the surface density of the second active material layer is determined.

2. The method according to claim 1, characterized in that: The determining the surface density of the second active material layer based on the surface density of the double-sided electrode sheet and the surface density of the first active material layer includes: The density difference between the surface density of the double-sided electrode sheet and the surface density of the first active material layer is determined as the surface density of the second active material layer.

3. The method according to claim 1, characterized in that In the first multi-roller calendering mechanism and the second multi-roller calendering mechanism, the last roller is a cold roller and the first roller is a hot roller.

4. The method according to claim 1, characterized in that In the first multi-roller calendering mechanism and the second multi-roller calendering mechanism, the diameter of the last roller and the diameter of the first roller are greater than the diameter of the second roller. The second roller is a roller other than the last roller and the first roller, and the second roller is used to calender the mixture into a film shape.

5. The method according to claim 4, characterized in that The diameter of the final roller and the diameter of the first roller adjacent to the final roller are 500-1200 mm, and the diameter of the second roller is 100-700 mm.

6. The method according to claim 1, characterized in that In the first multi-roller calendering mechanism and the second multi-roller calendering mechanism, the rolling pressure between the last roller and the first roller is greater than the rolling pressure between any other two adjacent rollers.

7. The method according to claim 1, characterized in that The determining of the surface density of the first active material layer during the process of transferring the single-sided electrode sheet to the second multi-roller rolling mechanism through the transmission component by the first multi-roller rolling mechanism comprises: In the process of transferring the single-sided electrode sheet to the second multi-roller calendering mechanism through the transmission component, determining the surface density of the first active material layer by a first surface density detector; The determining of the surface density of the double-sided electrode sheet during the process of the second multi-roller calendering mechanism transferring the double-sided electrode sheet to the winding mechanism through the transmission component comprises: In the process of transferring the double-sided electrode sheet to the winding mechanism through the transmission component, determining the surface density of the double-sided electrode sheet by a second surface density detector; Wherein, the first surface density detector and the second surface density detector respectively include a transmission ray surface density detector or an ultrasonic surface density detector.

8. The method according to claim 1, characterized in that The speed ratio of any two adjacent rollers along the calendering direction is 1:(1.05-4).

9. A double-sided electrode sheet manufacturing device, characterized in that: The device comprises: A feeding module, used for placing the mixed material between the roller with the smallest rotation speed and the adjacent roller in the first multi-roller calendering mechanism and the second multi-roller calendering mechanism, respectively, so that the mixed material is calendered and transferred between any two adjacent rollers of the first multi-roller calendering mechanism and the second multi-roller calendering mechanism; the first multi-roller calendering mechanism and the second multi-roller calendering mechanism respectively include at least three rollers arranged in sequence; the first multi-roller calendering mechanism and the second multi-roller calendering mechanism are connected by a transmission component and are arranged on different sides of the transmission component; The first forming module is used to place the double-sided carbon-coated foil current collector between the last roller of the first multi-roller calendering mechanism and the adjacent roller, and thermally compound the double-sided carbon-coated foil current collector and the mixed material so that the mixed material adheres to the first side of the double-sided carbon-coated foil current collector to form a first active material layer to obtain a single-sided electrode sheet; A first determination module, configured to determine the surface density of the first active material layer during the process in which the first multi-roller calendering mechanism transfers the single-sided electrode sheet to the second multi-roller calendering mechanism through the transmission component; A second forming module is used for, after the single-sided electrode sheet is transferred to the second multi-roller calendering mechanism through the transmission component, thermally compounding the single-sided electrode sheet and the mixed material through the last roller of the second multi-roller calendering mechanism and the roller adjacent thereto, so that the mixed material adheres to the second side of the double-sided carbon-coated foil current collector to form a second active material layer to obtain a double-sided electrode sheet; The second determination module is used to determine the surface density of the double-sided electrode sheet during the process of the second multi-roller calendering mechanism transferring the double-sided electrode sheet to the winding mechanism through the transmission component, and determine the surface density of the second active material layer based on the surface density of the double-sided electrode sheet and the surface density of the first active material layer.

10. A double-sided electrode sheet, characterized in that: The double-sided electrode sheet is manufactured by the double-sided electrode sheet manufacturing method according to any one of claims 1 to 8, or is manufactured by the double-sided electrode sheet manufacturing device according to claim 9.

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