Single-layer battery pole piece and preparation method and device thereof

Abstract

The invention provides a single-layer battery pole piece and a preparation method and device thereof. The method comprises the following steps: S1, preheating an electrode base material; s2, applying a high-voltage electric field to the electrode slurry through a conductive atomizing needle, and atomizing; the electrode slurry comprises electrode active material particles, a binder and a solvent; and S3, uniformly spraying the atomized electrode slurry on the surface of the preheated electrode base material in sequence, and curing to obtain the single-layer battery pole piece. According to the invention, the high-voltage electric field is applied to the liquid electrode slurry, the liquid electrode slurry is separated into tiny and uniform liquid drops, and the formed tiny liquid drops are pushed by the force of the electric field, sprayed out from the conductive atomizing needle, sprayed on the preheated electrode base material and cured to form a uniformly distributed single-layer electrode active material layer. Therefore, an extremely thin single-layer battery pole piece is manufactured; according to the process, the output capacity of a single-layer battery pole piece production line can be expanded, and the production capacity of large-scale or urgently-needed orders of enterprises is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of battery pole piece production, and in particular to a single-layer battery pole piece and a preparation method and device thereof. Background Art

[0002] A single-layer battery pole piece refers to a battery pole piece with a specially designed structure, in which the active materials of the positive and negative electrodes are concentrated in a single thin layer, rather than the multi-layer stacked structure of traditional pole pieces. This single-layer design can increase the reaction area of ​​the active material, thereby increasing the energy storage capacity and initial capacity of the battery; the extremely thin active material layer can form a shorter and more direct ion channel, thereby increasing the reaction rate of the battery. In the technical context of lithium battery technology constantly pursuing higher energy density, faster charge and discharge rates, and thinner battery volumes, the preparation of single-layer battery pole pieces has become an important research direction.

[0003] At present, the preparation method of single-layer battery pole pieces is still in the research stage. The following are some feasible preparation methods: Stripping stacking method: Prepare a multi-layer electrode structure, and then use mechanical, chemical or thermal stripping methods to separate the multiple layers to obtain a single-layer electrode pole piece. This method requires precise stripping technology to ensure the integrity of the single layer. Its advantage is that it can use existing multi-layer electrodes without the need for special preparation processes; it has a wide range of potential applicability and may be applicable to a variety of materials. The disadvantage is that the stripping technology requires delicate operation, which can easily cause damage to the single layer and is difficult to achieve.

[0004] Solution impregnation method: The solution of active material is impregnated onto the substrate material, and then the electrode is made by drying and curing. The single-layer distribution of active material on the substrate can be achieved by controlling the coating speed, material concentration and drying conditions during the impregnation process. Its advantage is that the preparation steps are relatively simple and do not require complex equipment and conditions; the disadvantage is that the uniformity of the solution impregnation method may be difficult to accurately control, and the prepared single-layer battery electrode may have certain fluctuations in performance and quality.

[0005] Chemical vapor deposition: Using chemical vapor deposition technology, active material molecules are deposited on the substrate to form a monolayer structure. By controlling the gas flow, temperature and reaction time during the deposition process, a monolayer distribution of active materials can be achieved. Its advantage is that it can achieve precise control at the atomic level and prepare high-quality monolayer structures. The disadvantages are that it requires special equipment and conditions, and the cost is relatively high; it is suitable for some active materials, but not for all materials; the preparation time may be long, and it is not suitable for efficient large-scale production.

[0006] In addition to the production methods in the above research stage, the most widely used production method in the production of traditional multi-layer battery pole pieces in the current lithium battery industry is the slit extrusion coating method. It is mainly produced by a coating die head composed of an upper die head, a lower film head, and a gasket. The upper die head and the lower die head are fixedly connected, and a gasket with a sunken surface is clamped therein, and a coating slit is formed after combination; the feeding system transports the slurry to the coating head, squeezes it out of the slit to form a liquid film, and then coats it on the moving current collector foil, and forms a uniform coating after drying. The advantage of this method is that the pole piece is very uniform and precise after coating, and the coating edge has high flatness. Its disadvantage is that it is limited by the processing capacity of the coating die head and the gasket, and it is impossible to produce extremely thin single-layer battery pole pieces through slit extrusion.

[0007] The above existing single-layer battery electrode preparation methods generally have the following defects: (1) The technical feasibility and economic feasibility are low, which has a significant impact on the overall performance, cost-effectiveness and reliability of subsequent batteries; (2) The consistency of production quality cannot be guaranteed, which affects many important performance indicators of the battery and leads to unstable performance of the battery during the charging and discharging process; some electrodes are subjected to uneven stress during the cyclic charging and discharging process, thereby shortening the cycle life of the battery; some electrodes behave abnormally during the charging and discharging process, increasing the possibility of safety risks such as overheating and leakage of the battery; the overall energy density of the battery decreases, thereby reducing the battery's endurance; (3) The production efficiency is low, which limits the output capacity of the production line, thereby limiting the company's production capacity to meet large-scale or urgent orders, which is not conducive to industrialization.

[0008] The Chinese patent literature discloses "a battery pole piece extrusion coating die head", and its announcement number is CN113083612A. This invention is further provided with a coating adjustment mechanism on the basis of a conventional die head mechanism. The coating adjustment mechanism includes an adjustment block corresponding to the slurry extrusion coating area of ​​the gasket, and a pull rod connected to the adjustment block in a transmission manner; under the screwing action of the differential bolt, the pull rod can drive the adjustment block to squeeze the slurry extrusion coating area of ​​the gasket downward or pull the adjustment block upward away from the slurry extrusion coating area of ​​the gasket, thereby adjusting the slurry coating thickness. This design can further adjust the required coating thickness based on the coating thickness limited by the gasket thickness. However, this process cannot break away from the scope of traditional multi-layer pole pieces, and is not feasible for the preparation of single-layer battery pole pieces. Summary of the invention

[0009] In view of the shortcomings of the prior art mentioned above, the purpose of the present invention is to provide a single-layer battery pole sheet and a preparation method and device thereof, which are used to solve the technical problems of poor production consistency, low preparation efficiency and unsuitability for the preparation of single-layer battery pole sheets in the existing battery pole sheet preparation process.

[0010] To achieve the above-mentioned and other related purposes, the present invention provides a method for preparing a single-layer battery electrode sheet, comprising the following steps: S1: preheating the electrode substrate; S2: applying a high voltage electric field to the electrode slurry through a conductive atomizing needle to perform atomization; the electrode slurry includes electrode active material particles, a binder and a solvent; S3: spraying the atomized electrode slurry uniformly on the surface of the preheated electrode substrate in sequence, curing it, and obtaining a single-layer battery electrode sheet.

[0011] In the above technical scheme of the present application, a single-layer battery pole piece is made by using a high-voltage electric field. The principle is that the liquid electrode slurry is polarized and the charge distribution on the liquid surface is uneven under the action of the high-voltage electric field. When the electric field is strong enough, under the joint action of the electric field force and the Coulomb force, the liquid electrode slurry is separated into tiny and uniform droplets. The formed tiny droplets are pushed by the electric field force and ejected from the conductive atomizing needle. They are sprayed on the preheated electrode substrate and solidified to form a uniformly distributed single-layer electrode active material layer, thereby making an extremely thin single-layer battery pole piece. The main role of the conductive atomizing needle in the production process of a single-layer battery pole piece is based on the tip effect. The high-voltage electric field on the conductive atomizing needle is superimposed on the needle tip, so that the electrode slurry at the needle tip is fully polarized. Under the joint action of the electric field force and the Coulomb force, the electrode slurry is ejected into fine droplets to form a spray, thereby forming a uniform coating on the electrode substrate. The process of the present invention can realize the rapid and efficient production of single-layer battery pole pieces, meeting the production efficiency requirements required for industrial production.

[0012] Preferably, the electrode substrate is a current collector substrate.

[0013] Preferably, in step S1, the preheating temperature of the electrode substrate is not lower than the boiling point of the solvent. Preheating to a temperature higher than the boiling point of the solvent is beneficial to quickly volatilize the solvent in the electrode slurry sprayed on the electrode substrate to form a single-layer electrode active material layer, thereby improving the curing efficiency and avoiding the agglomeration of the electrode active material particles sprayed on the electrode substrate, which affects the single-layer effect and spraying uniformity.

[0014] Preferably, in step S1, the preheating temperature of the electrode substrate is not higher than the thermal decomposition temperature of the binder. Although too high a preheating temperature will accelerate the volatilization of the solvent, it will destroy the stability of the binder or other components in the electrode slurry, resulting in the risk of failure of the electrode active material layer. Therefore, it is best to control it within the above range.

[0015] Preferably, in step S2, the inner diameter of the conductive atomization needle is 8 to 30 times the average particle diameter of the electrode active material particles.

[0016] Preferably, the conductive atomization needle includes a metal needle or a conductive capillary needle.

[0017] The structure, inner and outer diameters, and materials of the conductive atomizing needle have an important influence on the electric field distribution on the needle, and thus have an important influence on the spray morphology, atomization effect, and stable state of the electrospray. The inner diameter of the conductive atomizing needle has a critical influence on the spraying effect. The larger the inner diameter, the larger the spraying width, and the more spraying per unit time. The above inner diameter range can allow the electrode active material particles in the electrode slurry to be sprayed out smoothly, and can avoid excessive spraying width, so that the spraying amount can be controlled, which is conducive to the formation of a single-layer electrode active material layer, thereby making an extremely thin single-layer battery electrode. The material of the conductive atomizing needle is not limited, and its conductivity can ensure the stability of the internal high-voltage electric field as a benchmark. The stable electric field distribution is conducive to improving the stability of the spraying.

[0018] Preferably, during spraying, the relative position of the electrode substrate and the conductive atomizing needle is adjusted in real time to achieve uniform spraying of the electrode slurry on the surface of the electrode substrate. A specific spraying trajectory can be designed to achieve uniform spraying.

[0019] Preferably, the relative position is the relative position of the conductive atomization needle and the electrode substrate along a direction parallel to the electrode substrate.

[0020] The height change between the conductive atomization needle and the substrate usually has a direct impact on the spraying format and spraying density. The spraying effect can be controlled by adjusting the height. By adjusting the relative position of the conductive atomization needle parallel to the electrode substrate, the spraying position can be changed to achieve the regulation of the production efficiency of the single-layer battery pole piece to match the requirements of industrial production efficiency.

[0021] The present application also provides a single-layer battery electrode produced by the above-mentioned preparation method.

[0022] Preferably, the single-layer battery electrode sheet comprises an electrode substrate and a single-layer electrode active material layer coated on the surface of the electrode substrate, wherein the single-layer electrode active material layer is formed by solidifying the electrode slurry on the surface of the electrode substrate; the thickness of the single-layer electrode active material layer is similar to the average particle size of the electrode active material particles.

[0023] The present application also provides a preparation device for a single-layer battery electrode sheet, which is applied to the above-mentioned preparation method. The preparation device for the single-layer battery electrode sheet includes a feed pipe for containing electrode slurry, a conductive atomization needle connected to the feed pipe, a heating suction cup for fixing and preheating an electrode substrate, a high-voltage DC power supply for applying a controllable high-voltage electric field to the conductive atomization needle, a position adjustment mechanism and a feed control mechanism for controlling the spraying amount of the electrode slurry in the feed pipe. The position adjustment mechanism is used to drive the electrode substrate or the conductive atomization needle to move so that the electrode slurry is evenly sprayed on the surface of the electrode substrate.

[0024] Preferably, the positive electrode of the high-voltage DC power supply is connected to the conductive atomizing needle, and the negative electrode is connected to the heating chuck and grounded. The high-voltage DC power supply can output a stable DC voltage in the range of 0-10kV, and has built-in protection functions such as overcurrent, overvoltage, and overheating.

[0025] Preferably, the feed control mechanism is an air pressure control system. The system uses an ultra-small-scale high-precision air pressure controller, which can perform high-precision air pressure control in the range of -1 to 1 PSI (Pounds per square inch), with a control accuracy of up to 0.5% FS (Full-scale), and is connected to the conductive atomization needle through an air pipe and related adapters to control the feed of the flow channel in the conductive atomization needle. This system has the following functions in the production process of single-layer battery electrodes: (1) In the non-working state, the electrode slurry in the flow channel is balanced by negative pressure control to avoid continuous and uninterrupted outflow; (2) In the working state, the feed matching of different materials and different electric field states is achieved through ultra-small-scale high-precision positive and negative pressure control, so as to achieve the effect of continuously spraying atomized electrode materials at the metal needle tip; (3) In the trial printing stage, it is easy to control the outflow of electrode slurry, thereby ensuring that the flow channel is unobstructed and the electrode slurry in the flow channel is full.

[0026] Preferably, a plurality of adsorption holes are provided on the surface of the heating suction cup, the adsorption holes are connected to a negative pressure generator, and a heating element is provided inside the heating suction cup.

[0027] Preferably, the position adjustment mechanism includes a Z-direction motion module for driving the conductive atomization needle to reciprocate in a direction perpendicular to the electrode substrate and an XY-direction motion module for driving the electrode substrate or the conductive atomization needle to move in a horizontal direction.

[0028] Preferably, the Z-direction motion module is fixedly connected to the conductive atomization needle, the XY-direction motion module is fixedly connected to the heating chuck, and the XY-direction motion module is used to drive the electrode substrate to move in a horizontal direction relative to the conductive atomization needle.

[0029] The Z-axis motion module and the XY-axis motion module are beneficial to the control of the motion trajectory during the spraying process.

[0030] As described above, the single-layer battery pole piece and the method and device for preparing the same of the present invention have the following beneficial effects: (1) The present invention applies a high voltage electric field to the liquid electrode material to fully polarize the liquid electrode slurry in the conductive atomizing needle. Under the combined action of the electric field force and the Coulomb force, the electrode slurry is ejected into fine droplets to form a spray, thereby forming a uniform coating on the electrode substrate to achieve the production of a single-layer battery electrode sheet. The process of the present invention can expand the output capacity of a single-layer battery electrode sheet production line and improve the production capacity of an enterprise for large-scale or urgent orders; (2) Before spraying, the electrode substrate is heated to the boiling point of the solvent by a heating chuck, so that the electrode slurry is immediately solidified when sprayed on the substrate to avoid agglomeration of the electrode active material particles sprayed on the substrate, so that the single-layer battery electrode sheet prepared by the process of the present invention has high consistency, which can ensure that the electrode sheet is subjected to balanced stress during the cyclic charge and discharge process, and ensure the stable performance of the battery during the charge and discharge process; (3) The single-layer battery pole piece preparation device of the present invention has a simple structure and is easy to install and disassemble, which is conducive to improving the controllability of process parameters and ensuring the consistency of single-layer battery pole piece products. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Shown is a simplified schematic diagram of the structure of a single-layer battery electrode preparation device.

[0032] Figure 2 Shown is a schematic diagram of the principle of the method for preparing a single-layer battery electrode.

[0033] Figure 3 Shown is a schematic diagram of the spraying trajectory of a single-layer battery electrode.

[0034] Figure 4 Shown is a SEM image of the single-layer battery electrode prepared in Example 1.

[0035] Figure 5 Shown is a local height measurement diagram of the measurement point at A of the single-layer battery pole piece prepared in Example 1.

[0036] Figure 6 Shown is a local height measurement diagram of the measurement point B of the single-layer battery electrode sheet prepared in Example 1.

[0037] Figure 7 Shown is a local height measurement diagram of the measurement point C of the single-layer battery electrode prepared in Example 1.

[0038] Description of Figure Numbers 1 Electrode substrate 2 Single-layer electrode active material layer 3 Conductive atomization needle 4 Heating Suction Cup 5 High voltage DC power supply 6 Feed control mechanism 7 Relay 8 Electrode slurry DETAILED DESCRIPTION

[0039] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0040] It should be noted that the process equipment or devices not specifically specified in the following embodiments are all conventional equipment or devices in the art.

[0041] In addition, it should be understood that one or more method steps mentioned in the present invention do not exclude the existence of other method steps before or after the combination step or the insertion of other method steps between these explicitly mentioned steps, unless otherwise specified; it should also be understood that the combination connection relationship between one or more devices / apparatuses mentioned in the present invention does not exclude the existence of other devices / apparatuses before or after the combination device / apparatus or the insertion of other devices / apparatuses between these two explicitly mentioned devices / apparatuses, unless otherwise specified. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or the scope of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the present invention without substantially changing the technical content.

[0042] The design of each parameter in the following embodiments of the present application is described as follows: X-direction movement interval: This parameter is usually set to the diameter of the spraying width under the current parameters (i.e., the diameter of the spraying surface formed by a single spraying in situ, and the spraying surface is approximately a circle). After one cycle of spraying according to this parameter setting, the X-direction interval of the center line trajectory formed by the spraying surface is half of the diameter of the spraying surface, which can be called two-equal-division spraying in this invention; generally speaking, the more equal divisions, the greater the density of the single-layer pole piece produced in one cycle. According to the actual surface density requirements or the current single spraying density, more equal division spraying can be designed with reference to the above trajectory principle to meet the use requirements; X-direction movement interval times: This parameter is combined with the X-direction movement interval to set the X-direction distance of the total spraying area; Y-direction movement distance: used to set the Y-direction distance of the total spraying area; X-axis movement speed: There is no special requirement for this parameter setting. It is usually set to a larger value, but not so large as to affect the spraying stability. Y-axis movement speed: This parameter is set according to the actual production efficiency requirements, surface density requirements, and the diameter of the single spraying surface. Usually, the speed is greater than the proportional relationship with the diameter of the spraying surface, which is convenient for analyzing the density law of the produced electrode surface. Number of cycles: In the present invention, the electrode produced by one cycle of spraying is called a single-layer electrode. Multiple cycles of spraying can produce thinner multi-layer electrode. The user can set it according to actual needs.

[0043] Example 1 like Figure 1 As shown, the embodiment of the present application provides a single-layer battery electrode sheet preparation device, including a feed pipe for accommodating electrode slurry, a conductive atomizing needle 3 connected to the feed pipe, a heating sucker 4 for fixing and preheating the electrode substrate, a high-voltage DC power supply 5 for applying a controllable high-voltage electric field to the conductive atomizing needle, a position adjustment mechanism and a feed control mechanism 6 for controlling the ejection amount of the electrode slurry in the feed pipe, wherein the feed control mechanism is an air pressure control system, the conductive atomizing needle adopts a metal needle, the high-voltage DC power supply is connected to a relay 7, the positive electrode of the high-voltage DC power supply is connected to the conductive atomizing needle, and the negative electrode is connected to the heating sucker and grounded at the same time. The high-voltage DC power supply can output a stable DC voltage in the range of 0-10kV. The position adjustment mechanism is used to drive the electrode substrate or the conductive atomizing needle to move so that the electrode slurry is evenly sprayed on the surface of the electrode substrate. The surface of the heating sucker is provided with a plurality of adsorption holes, the adsorption holes are connected to a negative pressure generator, and a heating element is provided in the heating sucker. The position adjustment mechanism includes a Z-direction motion module for driving the conductive atomization needle to reciprocate in a direction perpendicular to the electrode substrate and an XY-direction motion module for driving the electrode substrate to move in a horizontal direction. The Z-direction motion module is fixedly connected to the conductive atomization needle, and the XY-direction motion module is fixedly connected to the heating chuck, and the XY-direction motion module is used to drive the electrode substrate to move in a horizontal direction relative to the conductive atomization needle. The Z-direction motion module is a Z-direction servo motor module.

[0044] The present application also provides a method for preparing a single-layer battery electrode sheet using the above device, comprising the following steps: S1: The heating chuck 4 is fixedly mounted on the XY motion module, and a negative pressure generator is used to make the adsorption hole of the heating chuck 4 generate negative pressure to adsorb and fix the electrode substrate, and a heating element is used to preheat the electrode substrate to 210° C.; S2: Use tweezers to remove the tail plug in the feed tube that has been assembled with electrode materials, connect it to the air pressure control system through an adapter, turn on the air pressure control system, set the air pressure to -0.05PSI (negative pressure), remove the protective cover at the bottom of the feed tube (the top of the feed tube is the loading port, which is sealed with a tail plug; the bottom is the discharge port, which is sealed with a protective cover), and install a metal needle with an inner diameter of 250μm through the adapter; fix the metal needle to the Z-direction servo electrode module through a fixing fixture to ensure that the metal needle is perpendicular to the surface of the heating chuck; the electrode slurry includes electrode active material particles, a binder and a solvent, and the solvent is NMP (N-Methyl-2-pyrrolidone, N-methylpyrrolidone) with a boiling point of about 202°C; the average particle size of the electrode active material particles is 20μm; Pre-discharging: Control the XY motion module to make the trial printing area (the trial printing area can be a small area artificially divided on the electrode substrate, which corresponds to the working area; it can also be to fix two smaller substrates on the suction cup, select one as the trial printing area, and the other for the working area) located directly below the metal needle (at this time, the height of the metal needle from the substrate is the fixed height after the module returns to zero, about 50mm), set the air pressure to 0.5PSI, and observe whether the metal needle can discharge normally through the observation camera. After ensuring that the metal needle can discharge smoothly and the electrode material is filled in the entire flow channel, set the air pressure back to -0.05PSI; Test spraying: turn on the high-voltage DC power supply 5, and gradually increase the DC voltage applied to the metal needle by controlling the knob of the relay 7. When the DC voltage increases to 5kV, a relatively stable intermittent atomization spraying phenomenon occurs at the metal needle. Set the air pressure to 0.08PSI, and then an uninterrupted atomization spraying phenomenon occurs at the metal needle (in order to avoid the influence of the electric field change caused by the movement of the heating chuck during the production process, the actual production voltage is usually set slightly higher than the test spraying voltage, that is, the DC voltage has a margin and is set to 5.2kV); S3: According to the production requirements, set the relevant parameters of the production trajectory, control the XY motion module, and make the electrode substrate 1 move according to the designed trajectory under the metal needle to perform electrode spraying. The designed trajectory parameters mainly include X-direction movement interval, X-direction movement interval number, Y-direction movement distance, X-direction movement speed, Y-direction movement speed, and cycle number; the spraying trajectory is as follows: Figure 3 As shown, after completing one serpentine spraying, the heating suction cup moves in the X direction at an interval of half the X direction movement, and performs a reverse serpentine spraying. The two sprayings are completed, that is, one cycle. Under the current conditions, the diameter of the metal needle's single spraying width is about 32mm, so the X direction movement interval is set to 32mm, the Y direction movement distance is set to a moderate 8mm / s, and the X direction movement speed is set to 40mm / s, which does not affect the continuous spraying. Under the current parameters, the rapid production of single-layer battery electrodes can be achieved.

[0045] Spraying stop: In addition to the above trajectory description, the end point of the trajectory route is usually controlled to stop the test printing area. At the same time, the connection between the metal needle and the positive pole of the high-voltage DC power supply is closed through relay control. At this time, spraying stops and the electrode production is completed (if a multi-layer electrode is produced or the electrode thickness is thick, secondary heat curing may be required to complete the production of the electrode); Safety shutdown: Rotate the knob of the high-voltage DC power supply to gradually reduce the DC voltage to zero and turn off the high-voltage DC power supply; turn off the suction cup heating, and control the XY motion module to move the suction cup to the upper and lower workpiece positions (preset positions for easy loading and unloading by operators); when the temperature of the heated suction cup drops to room temperature, turn off the negative pressure and remove the single-layer battery electrode. At this point, the process flow of electrode production is completed.

[0046] like Figure 2 As shown, the single-layer battery electrode sheet prepared by the process of this embodiment includes an electrode substrate 1 and a single-layer electrode active material layer 2 coated on the surface of the electrode substrate, and the single-layer electrode active material layer is formed by curing the electrode slurry on the surface of the electrode substrate.

[0047] The morphology of the surface single-layer electrode active material layer of the single-layer battery electrode sheet prepared by the process of this embodiment was characterized by a scanning electron microscope. The SEM image is as follows: Figure 4 As shown, from Figure 4 It can be seen that most of the electrode active material particles are evenly distributed on the electrode substrate in a single layer form (without stacking between particles).

[0048] Three test points A, B and C on the surface of the single-layer electrode active material layer of the single-layer battery electrode sheet prepared in this embodiment were randomly selected, and local height measurement was performed using an OLYMPUS digital microscope and analyzed using DSX10-BSW software. The results are as follows: Figure 5 , Figure 6 and Figure 7 As shown, Figure 5 The middle height is shown as 20.847μm, Figure 6 The middle height is shown as 20.664μm, Figure 7 The middle height is shown as 20.207 μm, which is close to the average particle size of the electrode active material particles of 20 μm. It can be seen that the single-layer battery electrode was successfully prepared in this application.

[0049] Example 2 The difference between Example 2 and Example 1 is that the XY motion module is fixedly connected to the conductive atomization needle, and the XY motion module is used to drive the conductive atomization needle to move horizontally relative to the electrode substrate, and the rest of the structure and process are exactly the same.

[0050] This embodiment realizes the control of the spraying trajectory by adopting a mobile conductive atomizing needle, and the spraying pattern can be designed according to the spraying requirements, with high flexibility and strong controllability.

[0051] The characterization method and results of the single-layer battery electrode prepared in this embodiment are equivalent to those in Example 1 and will not be described in detail here.

[0052] The above embodiments are only illustrative of the principles and effects of the present invention. In practical applications, the size of a single spraying width can be controlled by changing the structure of the conductive atomizing needle, selecting different specifications of the conductive atomizing needle, changing the height between the conductive atomizing needle and the electrode substrate, etc., and the efficiency of single-layer battery electrode production can be controlled by changing the Y-axis movement speed to match the requirements of industrial production efficiency.

[0053] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for preparing a single-layer battery pole piece, characterized in that: The following steps are involved: S1: preheating the electrode substrate; S2: applying a high voltage electric field to the electrode slurry through a conductive atomizing needle to perform atomization; the electrode slurry includes electrode active material particles, a binder and a solvent; S3: spraying the atomized electrode slurry uniformly on the surface of the preheated electrode substrate in sequence, curing it, and obtaining a single-layer battery electrode sheet.

2. The preparation method according to claim 1, characterized in that: In step S1, the preheating temperature of the electrode substrate is not lower than the boiling point of the solvent.

3. The preparation method according to claim 1, characterized in that: In step S1, the preheating temperature of the electrode substrate is not higher than the thermal decomposition temperature of the binder.

4. The preparation method according to claim 1, characterized in that: In step S2, the inner diameter of the conductive atomization needle is 8 to 30 times the average particle diameter of the electrode active material particles.

5. The preparation method according to claim 1, characterized in that: During spraying, the relative position of the electrode substrate and the conductive atomizing needle is adjusted in real time to achieve uniform spraying of the electrode slurry on the surface of the electrode substrate.

6. The preparation method according to claim 5, characterized in that: The relative position is the relative position between the conductive atomization needle and the electrode substrate along a direction parallel to the electrode substrate.

7. A single-layer battery electrode produced by the production method according to any one of claims 1 to 6.

8. The single-layer battery pole piece according to claim 7, characterized in that: The invention comprises an electrode substrate (1) and a single-layer electrode active material layer (2) coated on the surface of the electrode substrate, wherein the single-layer electrode active material layer is formed by solidifying electrode slurry on the surface of the electrode substrate.

9. A single-layer battery electrode preparation device, characterized in that: Applied to the preparation method as described in any one of claims 1 to 6, the preparation device of the single-layer battery electrode sheet includes a feed pipe for containing electrode slurry, a conductive atomization needle (3) connected to the feed pipe, a heating suction cup (4) for fixing and preheating the electrode substrate, a high-voltage DC power supply (5) for applying a controllable high-voltage electric field to the conductive atomization needle, a position adjustment mechanism and a feed control mechanism (6) for controlling the spraying amount of the electrode slurry in the feed pipe, wherein the position adjustment mechanism is used to drive the electrode substrate or the conductive atomization needle to move so that the electrode slurry is evenly sprayed on the surface of the electrode substrate.

10. The preparation device according to claim 9, characterized in that: The feeding control mechanism is a pneumatic control system.

11. The preparation device according to claim 9, characterized in that: A plurality of adsorption holes are arranged on the surface of the heating suction cup, and a negative pressure generator is connected to the adsorption holes. A heating element is arranged inside the heating suction cup.

12. The preparation device according to claim 9, characterized in that: The positive electrode of the high-voltage direct current power supply is connected to the conductive atomizing needle, and the negative electrode is connected to the heating suction cup and is grounded at the same time.

13. The preparation device according to claim 9, characterized in that: The position adjustment mechanism includes a Z-direction motion module for driving the conductive atomization needle to reciprocate in a direction perpendicular to the electrode substrate and an XY-direction motion module for driving the electrode substrate or the conductive atomization needle to move in a horizontal direction.

14. The preparation device according to claim 13, characterized in that: The Z-direction motion module is fixedly connected to the conductive atomization needle, and the XY-direction motion module is fixedly connected to the heating chuck. The XY-direction motion module is used to drive the electrode substrate to move in a horizontal direction relative to the conductive atomization needle.

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