A solid-state battery bifacial electrode, its preparation method and rolling device

Abstract

This invention belongs to the field of lithium-ion battery technology, specifically relating to a solid-state battery bifacial electrode sheet, and further disclosing its preparation method and a rolling device for processing the bifacial electrode sheet. The preparation method of the bifacial electrode sheet of this invention employs a dry method to prepare a continuous active layer. After the active layer is stamped to the required size, a continuous rolling device is used to simultaneously roll the selected two active layers with a selected current collector strip. Since the active layer is a dry-process positive electrode active layer, and the upper and lower active layers are prepared in the same batch, its internal conductive network and material distribution have high consistency. The upper and lower layers do not experience uneven distribution of secondary material particles due to gravity. Combined with the simultaneous rolling technology of sides A and B, this greatly ensures the consistency of sides A and B of the bifacial electrode sheet, providing a reference for the continuous preparation of dry-process electrode sheets and contributing to improved battery cycle stability.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery technology, specifically relating to a solid-state battery bifacial electrode sheet, and further disclosing its preparation method and a rolling device for processing the bifacial electrode sheet. Background Technology

[0002] With technological advancements and the promotion of new national standards, lithium batteries have gained widespread application in numerous fields due to their advantages such as environmental friendliness, long lifespan, and relatively light weight. In particular, their high energy density, long cycle life, and excellent rate performance have made them the primary choice for portable electronic devices and electric vehicles. A lithium-ion battery is a comprehensive system assembled from positive and negative electrodes, a separator, and an electrolyte (in solid-state batteries, the separator and electrolyte are replaced by a solid electrolyte layer). When the battery is working, electrons and ions are transported within the microstructure of the electrodes, resulting in a series of chemical and electrochemical reactions. Therefore, the conductivity of the battery electrodes and the uniformity of the conductive network are crucial factors affecting the performance of lithium-ion batteries.

[0003] Solid-state batteries significantly improve battery system safety and simultaneously increase energy density by replacing traditional flammable organic liquid electrolytes with non-flammable solid electrolytes. Among various novel battery systems, solid-state batteries are the next-generation technology closest to industrialization, a consensus shared by industry and the scientific community. Sulfide electrolytes, such as thio-LISICON, Li6PS5Cl, and Li..., exhibit relatively high lithium-ion conductivity. 10 GeP2S 12 Li6PS5Cl, Li 10 SnP2S 12 Li₂S-P₂S₅, Li₂S-SiS₂, Li₂S-B₂S₃, etc., have room temperature ionic conductivity reaching 10. -3 -10 -2 With a S / cm ratio approaching or even exceeding that of organic electrolytes, it also boasts advantages in high-power and high- and low-temperature solid-state batteries due to its high thermal stability, good safety performance, and wide electrochemical stability window (above 5V).

[0004] In solid-state battery systems, when using sulfide solid electrolytes to prepare all-solid-state cells, the sulfide electrolyte, being a ceramic material, leads to the formation of solid-solid contact surfaces within the resulting pouch cell. Therefore, impedance arises due to poor solid-solid interface contact between the electrolyte itself, between the electrolyte and the conductive agent, between the electrolyte and the active material, between the conductive agent and the active material, and between the electrode and the electrolyte membrane, thus affecting battery performance. Furthermore, if the thicknesses of the A and B sides of the bifacial electrodes are inconsistent, multiple electrode layers within the battery may crack locally due to uneven internal and external forces during cycling, leading to micro-short circuits or direct short circuits and rendering the battery unusable. Therefore, solid-state batteries require higher uniformity of electrode surfaces to ensure performance. Currently, in all-solid-state battery testing and applications, a certain amount of pressure needs to be applied externally to ensure the stability of the solid-solid contact surfaces and suppress volume expansion, thus guaranteeing optimal performance.

[0005] For the fabrication process of electrodes, especially bifacial electrodes, most currently employ bifacial single-layer fabrication (coating or transfer), meaning that side A is prepared first, followed by side B. Currently, methods for evaluating the uniformity of electrode fabrication on both sides mainly involve measuring thickness, areal density, and resistance differences. However, due to variations in fabrication time and process sequence, the consistency of the active layers on sides A and B is often affected. These differences inevitably lead to poor battery consistency. In particular, differences in the coatings on sides A and B can cause the following problems: inconsistent areal density, or inconsistent utilization of active materials due to different conductivity, resulting in different N / P ratios on sides A and B. This may lead to lithium deposition on one side while the other side does, reducing battery coulombic efficiency or causing micro-short circuits and short circuits. Alternatively, differences in conductivity and ion transport paths on sides A and B can result in different degrees of lithiation or state of charge on both sides. During long-term cycling, the accumulated stress on sides A and B can cause cracks in the electrode and coating failure. Similarly, the above two problems also exist in the parallel direction of the differences on each of the A and B surfaces. It can be seen that the non-uniformity of bifacial electrodes brings significant difficulties to the preparation and application of high-energy, high-performance energy density batteries, and also seriously affects the safety and application performance of batteries. The special requirements of bifacial electrodes for the stability of both electrodes also make the existing technology of using dry rolling to prepare bifacial electrodes, which rolls different electrodes of the positive and negative electrodes on both sides of the current collector, unsuitable for the stability requirements of bifacial electrodes; especially the special characteristics of dry bifacial electrodes, namely the requirements of some multi-layer stacked all-solid-state batteries and the edge frame structure of their electrodes, also make it impossible to use the method of large-size bifacial composite followed by cutting small electrodes, as is the case with liquid, semi-solid and some low-layer all-solid-state batteries.

[0006] Therefore, ensuring the uniformity of the coating on the A and B sides of the bifacial electrode is of great significance to the performance of solid-state batteries. Summary of the Invention

[0007] Therefore, the technical problem to be solved by the present invention is to provide a solid-state battery bifacial electrode sheet, wherein the thickness distribution, areal density and resistivity of the A and B sides of the electrode sheet are more consistent and the application performance is better.

[0008] The second technical problem to be solved by the present invention is to provide a continuous preparation method for solid-state battery bifacial electrodes, which can effectively improve the consistency of thickness distribution, areal density and resistivity of positive electrode AB side, and is applicable to the preparation of multiple types of electrodes such as positive electrode and negative electrode, which is beneficial to improving production efficiency and battery cycle stability.

[0009] The third technical problem to be solved by the present invention is to provide a rolling device for processing the bifacial electrode sheet of the solid-state battery.

[0010] To solve the above-mentioned technical problems, the present invention provides a rolling device for processing bifacial electrodes of solid-state batteries, comprising a first rolling shaft, a second rolling shaft, and a third rolling shaft with opposite rotation directions. The selected current collector strip passes through the rolling gap formed by the first rolling shaft and the second rolling shaft under the drive of the second drive shaft, and the conveyor belt passes through the rolling gap formed by the second rolling shaft and the third rolling shaft under the drive of the first drive shaft.

[0011] The first and second active layers of the double-sided electrode are respectively placed at corresponding positions on the current collector strip and the conveyor belt, so that the first and second active layers completely overlap at the rolling gap formed by the first and second rolling shafts, and are rolled by the first and second rolling shafts to complete the double-sided rolling composite with the current collector strip to form the desired double-sided electrode.

[0012] Specifically, in the rolling device for processing bifacial electrodes of solid-state batteries, the first and second rolling shafts are hot rolling shafts, and the third rolling shaft is a cold rolling shaft.

[0013] Specifically, the rolling device for processing bifacial electrodes of solid-state batteries controls the temperature of the first rolling shaft and the second rolling shaft to be the same;

[0014] Preferably, the temperature of the first roller and the second roller is controlled to be 60-120°C.

[0015] Specifically, in the rolling device for processing solid-state battery bifacial electrodes, the surface roughness of the second rolling shaft is greater than that of the conveyor belt;

[0016] Preferably, the conveyor belt is a stainless steel conveyor belt.

[0017] Specifically, the rolling device for processing solid-state battery bifacial electrodes further includes at least one set of fourth and fifth rolling shafts arranged in the direction of movement of the current collector strip; the rotation directions of the fourth and fifth rolling shafts are opposite, and the bifacial electrodes complete a second rolling process through the rolling gap formed by the fourth and fifth rolling shafts;

[0018] Preferably, the fourth and fifth rollers are hot rollers;

[0019] Preferably, the rolling temperature of the fourth and fifth rollers is 60-120°C.

[0020] The present invention also discloses a method for preparing a solid electrode double-sided electrode sheet, including the step of simultaneously rolling and bonding the first active layer and the second active layer on both sides of the current collector using the rolling device.

[0021] Specifically, the method for preparing the solid-state double-sided electrode includes the following steps:

[0022] (1) Selected active material, conductive agent, solid electrolyte and binder are taken and processed by dry method to obtain a continuous first active layer and a continuous second active layer;

[0023] (2) The continuous first active layer and the continuous second active layer are respectively punched with a die to obtain the first active layer and the second active layer of the required size, and then set aside.

[0024] (3) The first active layer and the second active layer are respectively placed at the corresponding positions of the current collector strip and the conveyor belt, and synchronously rolled and compounded at the positions of the first and second roller shafts to obtain the desired double-sided electrode sheet.

[0025] The present invention also discloses a double-sided electrode sheet prepared by the aforementioned preparation method.

[0026] The present invention also discloses a lithium-ion battery comprising the above-described bifacial electrode.

[0027] The present invention also discloses a lithium-ion battery pack including the above-mentioned bifacial electrode.

[0028] The present invention also discloses a lithium-ion battery device including the above-described bifacial electrode.

[0029] The method for preparing the bifacial electrode of this invention employs a dry process to prepare a continuous active layer. The active layer is then stamped to the required size, or it is first trimmed to a larger size, combined with a current collector, and then stamped to the required size. A continuous rolling device is used to simultaneously roll-form the selected active layers on both sides with the selected current collector strip. Since the active layer is a dry-process positive electrode active layer, and the upper and lower active layers are prepared in the same batch, the internal conductive network and material distribution are highly consistent. The uneven distribution of secondary material particles due to gravity does not occur between the upper and lower layers. Combined with the simultaneous rolling technology of sides A and B, this greatly ensures the consistency of sides A and B of the bifacial electrode, providing a reference for the continuous preparation of dry-process electrodes and contributing to improved battery cycle stability. Attached Figure Description

[0030] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein...

[0031] Figure 1 A schematic diagram of the rolling device for preparing double-sided electrode sheets according to the present invention;

[0032] Figure 2 This is a schematic diagram of the electrode sampling position according to the present invention;

[0033] The reference numerals in the figure are as follows: 101-current collector roll, 102-current collector strip, 103-conveyor belt, 104-first conveyor shaft, 105-second conveyor shaft, 201-first active layer, 202-second active layer, 203-double-sided electrode sheet, 301-first roller, 302-second roller, 303-third roller, 304-fourth roller, 305-fifth roller. Detailed Implementation

[0034] The purpose of the solid-state bifacial battery processing method of the present invention is to uniformly coat the active material on both sides of the electrode sheet, which can be done by using a conventional rolling device.

[0035] As a possible approach, such as Figure 1The roller pressing device shown includes a first roller pressing shaft 301 and a second roller pressing shaft 302 rotating in opposite directions. A selected current collector roll 101 controls a current collector strip 102, which is conveyed under the drive of a second conveyor shaft 105. The current collector strip 102 passes through the first roller pressing shaft 301 and the second roller pressing shaft 302 and undergoes hot roller pressing. A first active layer 201 and a second active layer 202 formed of selected active material are placed on the current collector strip 102 and the conveyor belt 103 respectively in corresponding positions. The third roller pressing shaft 303 of the conveyor belt 103 rotates in the opposite direction to the second roller pressing shaft 302. When the third roller pressing shaft 303 and the first conveyor shaft 104 drive the conveyor belt 103 to move, the second active layer 202 located on the conveyor belt 103 moves towards the second roller pressing shaft 302. In this roller pressing device, the first conveyor shaft 104 and the second conveyor shaft 105 are only conveying components and do not perform the rolling action. Because the surface roughness of the second roller 302 is greater than that of the conveyor belt 103, and its temperature is controlled to be consistent with that of the first roller 301, the temperature range is approximately 60-120℃. The third roller 303 is a cold roller, and its main function is to roll the second active layer 202 on the conveyor belt 103 onto the surface of the second roller 302. With continuous conveying, the second active layer 202 on the second roller 302 and the first active layer 201 located on the current collector belt 102 overlap and meet at the current collector belt 102 between the first roller 301 and the second roller 302. Under the same force, they simultaneously complete the transfer and composite on the selected current collector belt 102, and the desired double-sided electrode 203 is obtained after processing, with consistent uniformity between the double-sided active layers. The conveyor belt 103 is made of stainless steel.

[0036] like Figure 1 The rolling device shown further includes a fourth rolling shaft 304 and a fifth rolling shaft 305 for secondary rolling of the double-sided electrode 203. The fourth rolling shaft 304 and the fifth rolling shaft 305 rotate in opposite directions and are both hot rolling shafts. The double-sided electrode 203, formed by the hot rolling of the first rolling shaft 301 and the second rolling shaft 302, can release its stress after a brief transport process, and then undergoes a secondary hot rolling treatment by the fourth rolling shaft 304 and the fifth rolling shaft 305 at a temperature range of 60-120℃ to enhance the adhesion between the active layer and the current collector, and also to provide a secondary leveling effect. Figure 1 In the roller pressing device shown, the fourth roller pressing shaft 304 and the fifth roller pressing shaft 305 can be set in several groups according to the cost and the quality requirements of the roller pressing active layer. Then, the prepared double-sided electrode sheet is die-cut to complete the processing of the required electrode sheet.

[0037] The double-sided electrode sheet of this invention is processed using the aforementioned rolling device. Compared with the traditional method of rolling one side first and then the other side, this method of simultaneously rolling the upper and lower active layers onto the current collector perfectly avoids the differences in thickness distribution, areal density, and conductive network between the A and B sides caused by the different rolling order of the upper and lower layers, the different rolling times and forces on the A and B sides, and the different hardness of the substrate. Furthermore, since it is a dry-process positive electrode active layer, the upper and lower active layers are prepared in the same batch, and the internal conductive network and material distribution are highly consistent. The upper and lower layers will not have uneven secondary material particle distribution due to gravity. Combined with the simultaneous rolling technology of the A and B sides, this greatly ensures the consistency of the A and B sides of the double-sided electrode sheet.

[0038] In the following embodiments of the present invention, the first active layer 201 and the second active layer 202 can be prepared by dry processing of selected active materials according to the requirements of the double-sided electrode to obtain a double-sided dry-process positive electrode for solid-state batteries. The first active layer 201 and the second active layer 202 can be the same or different, or the same active material can be selected with different additives. First, the selected active material, conductive agent, solid electrolyte and binder are ball-milled and dry-mixed according to the corresponding ratio, and then ground and rolled to the designed thickness or areal capacity. The rolled continuous active layer is then stamped using a die, and then the active layer is transferred to the current collector strip 102 and the conveyor belt 103 at fixed intervals (to ensure the corresponding position at the current collector strip 102). Figure 1 As shown, the first active layer 201 and the second active layer 202 are independent active layers located on the current collector belt 102 and the conveyor belt 103, respectively.

[0039] Example 1

[0040] Take the positive electrode active material NCM811@ Li2ZrO3: electrolyte Li6PS5Cl: conductive agent SP: binder PTFE, and mix them in a mass ratio of 86.5:12:1:0.5. Ball mill for 1 hour, then grind for 1 hour to mix them evenly. Then roll press at 120℃ until the active layer thickness reaches 60μm. Die cut in batches to a size of 5×9cm to obtain the required active layer for later use.

[0041] In this embodiment, the current collector is selected to be coated with double-sided carbon-coated aluminum foil, and the current collector roll 101 controls the transport of the double-sided carbon-coated aluminum foil strip.

[0042] The active layers are neatly transferred at 8cm intervals to the corresponding positions on the current collector strip 102 (carbon-coated aluminum foil, 12μm) and the conveyor belt 103 to ensure that the first active layer 201 and the second active layer 202 can overlap at the corresponding positions on the current collector strip 102. The surface linear velocity of the second roller 302 is controlled to be consistent with the conveying speed of the current collector strip 102 (carbon-coated aluminum foil), and the surface temperature of the second roller 302 is set to 90°C, while the temperatures of other rollers such as the third roller 303, the fourth roller 304, and the fifth roller 305 are controlled to 80°C. At the same time, the axial clearance between the first roller 301 and the second roller 302 is adjusted to change the force applied to the surfaces of the first active layer 201 and the second active layer 202. After the double-sided active layer is transferred, it is laminated on both sides of the current collector strip 102 and is flat and wrinkle-free. After the subsequent transfer of the double-sided active layer is completed, the double-sided electrode 203 can be obtained. Then, it is die-cut into 5×9cm electrode sheets to complete the preparation of the required electrode sheet.

[0043] Three processed double-sided electrodes were randomly selected as sample test electrodes. Sampling locations were taken at the four corners and the center of each electrode (sampling locations are as follows). Figure 2 The thickness, mass, and conductivity of the 1cm diameter stamped sample are shown in Table 1 below. The upper left corner, upper right corner, lower left corner, lower right corner, and center position are marked as positions 1, 2, 3, 4, and 5, respectively.

[0044] Table 1. Test results of double-layer positive electrode.

[0045]

[0046] As shown in Table 1, the maximum difference in thickness, the maximum difference in mass, and the maximum difference in conductivity of the bilayer electrode prepared in this embodiment are 1.07 μm and 0.75 g, respectively. -2 S / cm.

[0047] The above-mentioned three battery electrodes were stacked with a lithium indium anode to assemble a half cell. Under a holding voltage of 0.5 MPa, at 30°C, the first efficiency of 0.1C charge-discharge reached 99.1%, and the capacity retention rate was 90.8% after 500 cycles of 1C charge-discharge.

[0048] Comparative Example 1

[0049] The preparation method of the positive electrode active layer in this comparative example is the same as that in Example 1.

[0050] This comparative example uses a traditional processing method, first rolling a single-sided active layer onto the selected current collector strip, then rolling an active layer onto the other side, and finally preparing a double-sided electrode sheet.

[0051] Sampling was performed using the same method as in Example 1. The maximum difference in thickness of the bilayer electrode was measured to be 3.8 μm, the maximum difference in mass was 1.35 g, and the maximum difference in conductivity was 0.39 × 10⁻⁶. -2 S / cm. The above three battery electrodes were stacked with a lithium indium anode to assemble a half cell. Under a holding voltage of 0.5MPa, at 30℃, the first efficiency of 0.1C charge-discharge reached 99%, and the capacity retention rate of 500 cycles of 1C charge-discharge was 85.8%.

[0052] This is because, during the processing of the double-sided electrode, the first active layer is first laminated onto the current collector and has already been rolled. However, when the second active layer is rolled onto the current collector, the first active layer is still subjected to rolling force. Furthermore, the total number of rolling operations and the number of times the substrate is subjected to force are different. This results in different numbers of times the two active layers are subjected to force and different uniformity of force, which ultimately affects the consistency of the two active layers.

[0053] Example 2

[0054] Take the following materials for the negative electrode active material: micron-sized silicon: graphite: electrolyte Li6PS5Cl: conductive agent CNT: binder PTFE, and mix them in a mass ratio of 20:43.5:35:1:0.5. Ball mill for 1 hour, then grind for 1 hour to mix them evenly. Then roll press at 150℃ until the active layer thickness reaches 40μm. Die cut in batches to a size of 5×9cm to obtain the required active layer for later use.

[0055] In this embodiment, the current collector is selected as an 8μm double-sided carbon-coated copper foil, and the current collector roll 101 controls the transport of the double-sided carbon-coated aluminum-coated copper strip. The electrode composite preparation process is the same as in Example 1. After the electrode preparation is completed, three processed double-sided electrodes are randomly selected as sample test electrodes. Sampling is performed at the four corners and the center of each electrode (sampling positions are as follows). Figure 2 The thickness, mass, and conductivity of the 1cm diameter stamped sample are shown in Table 2 below. The upper left, upper right, lower left, lower right, and center positions are marked as positions 1, 2, 3, 4, and 5, respectively.

[0056] Table 2. Test results of double-layer negative electrode.

[0057]

[0058] As shown in Table 2, the maximum difference in thickness, the maximum difference in mass, and the maximum difference in conductivity of the bilayer negative electrode prepared in this embodiment are 0.71 μm and 0.04 g, respectively. -2 S / cm.

[0059] The above-mentioned three battery electrode sheets are stacked with the positive electrode sheet to form a half-cell. Under the holding voltage of 0.5MPa, at 30℃, the first efficiency of 0.1C charge and discharge reaches 88.92%, and the capacity retention rate of 500 cycles of 1C charge and discharge is 60.65%.

[0060] Comparative Example 2

[0061] The preparation method of the negative electrode active layer in this comparative example is the same as that in Example 2.

[0062] Using traditional processing methods, a single-sided active layer is first rolled onto the selected current collector strip, and then an active layer is rolled onto the other side to finally prepare a double-sided electrode.

[0063] Sampling was performed using the same method as in Example 2. The maximum difference in thickness of the bilayer electrode was measured to be 2.9 μm, the maximum difference in mass was 0.65 g, and the maximum difference in conductivity was 1.08 × 10⁻⁶. -2 S / cm. The above three battery electrodes were stacked with a lithium indium anode to assemble a half cell. Under a holding voltage of 0.5MPa, at 30℃, the first efficiency of 0.1C charge-discharge reached 99%, and the capacity retention rate of 500 cycles of 1C charge-discharge was 49.8%.

[0064] This is because, during the processing of the double-sided electrode, the first active layer is first laminated onto the current collector and has already been rolled. However, when the second active layer is rolled onto the current collector, the first active layer is still subjected to rolling force. Furthermore, the total number of rolling operations and the number of times the substrate is subjected to force are different. This results in different numbers of times the two active layers are subjected to force and different uniformity of force, which ultimately affects the consistency of the two active layers.

[0065] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A rolling device for processing bifacial electrodes of solid-state batteries, characterized in that, It includes a first roller, a second roller, and a third roller with opposite rotation directions. The selected current collector belt passes through the roller gap formed by the first roller and the second roller under the drive of the second drive shaft. The conveyor belt passes through the roller gap formed by the second roller and the third roller under the drive of the first drive shaft. The first and second active layers of the double-sided electrode are respectively placed at corresponding positions on the current collector strip and the conveyor belt, so that the first and second active layers completely overlap at the rolling gap formed by the first and second rolling shafts, and are rolled by the first and second rolling shafts to complete the double-sided rolling composite with the current collector strip to form the desired double-sided electrode.

2. The rolling device for processing bifacial electrodes of solid-state batteries according to claim 1, characterized in that, The first and second rollers are hot rollers, and the third roller is a cold roller.

3. The rolling device for processing bifacial electrodes of solid-state batteries according to claim 2, characterized in that, The temperatures of the first and second rollers are controlled to be the same.

4. The rolling device for processing bifacial electrodes of solid-state batteries according to claim 3, characterized in that, The temperature of the first and second rollers is controlled to be 60-120℃.

5. The rolling device for processing bifacial electrodes of solid-state batteries according to claim 1, characterized in that, The surface roughness of the second roller shaft is greater than that of the conveyor belt.

6. The rolling device for processing bifacial electrodes of solid-state batteries according to claim 5, characterized in that, The conveyor belt is a stainless steel conveyor belt.

7. The rolling device for processing bifacial electrodes of solid-state batteries according to any one of claims 1-6, characterized in that, The rolling device further includes at least one set of fourth and fifth rolling shafts arranged in the direction of movement of the current collector strip; the rotation directions of the fourth and fifth rolling shafts are opposite, and the double-sided electrode sheet completes the second rolling process through the rolling gap formed by the fourth and fifth rolling shafts.

8. The rolling device for processing bifacial electrodes of solid-state batteries according to claim 7, characterized in that, The fourth and fifth rollers are hot rollers.

9. The rolling device for processing bifacial electrodes of solid-state batteries according to claim 7, characterized in that, The rolling temperature of the fourth and fifth rollers is 60-120℃.

10. A method for preparing a solid-state double-sided electrode sheet, characterized in that, The method includes the step of simultaneously rolling and bonding the first active layer and the second active layer on both sides of the current collector using the rolling device described in any one of claims 1-9.

11. The method for preparing a solid-state double-sided electrode sheet according to claim 10, characterized in that, Includes the following steps: (1) Selected active material, conductive agent, solid electrolyte and binder are taken and processed by dry method to obtain a continuous first active layer and a continuous second active layer; (2) The continuous first active layer and the continuous second active layer are respectively punched with a die to obtain the first active layer and the second active layer of the required size, and then set aside. (3) The first active layer and the second active layer are respectively placed at the corresponding positions of the current collector strip and the conveyor belt, and synchronously rolled and compounded at the positions of the first and second roller shafts to obtain the desired double-sided electrode sheet.

12. A double-sided electrode sheet prepared by the preparation method of claim 10 or 11.

13. A lithium-ion battery, characterized in that, Includes the bifacial electrode as described in claim 12.

14. A lithium-ion battery pack, characterized in that, Includes the bifacial electrode as described in claim 12.

15. A lithium-ion battery device, characterized in that, Includes the bifacial electrode as described in claim 12.

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