Drying device and battery production system
By integrating an AC electric field and an insulating layer into the drying device, the problem of uneven distribution of battery electrode binder was solved, the adhesion and cohesion of the electrode were improved, and battery performance and production efficiency were enhanced.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-23
- Publication Date
- 2026-04-14
AI Technical Summary
In the existing technology, the binder is unevenly distributed in the thickness direction of the electrode during the drying process of the battery electrode, resulting in insufficient adhesion and cohesion, which affects the battery performance.
An AC electric field device is integrated into the drying unit, which causes the electrode to periodically change polarity in the AC electric field. Combined with an insulating layer and an adjustable electrode structure, this ensures that the particles of each component are evenly distributed in the thickness direction of the electrode, reducing contact short circuits caused by electrode vibration.
This achieves uniform distribution of all components in the electrode along the thickness direction, improves adhesion and cohesion, and enhances the bonding performance and production efficiency of the battery.
Smart Images
Figure CN224121612U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of batteries, and more specifically, to drying equipment and battery production systems. Background Technology
[0002] Batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. The battery manufacturing process has a significant impact on battery performance. Among the key processes, baking to reduce solvents (such as moisture) in the battery electrodes is an important step that requires further improvement. Utility Model Content
[0003] The first aspect of this application provides a drying apparatus, comprising:
[0004] The drying chamber has an internal conveyor channel for passing the electrode sheets to be dried through the drying chamber.
[0005] The electric field electrode includes a first electrode and a second electrode; the first electrode and the second electrode are disposed in the conveyor channel and are located on both sides of the thickness direction of the electrode sheet to be dried;
[0006] An AC signal module, the output of which is connected to the electric field electrode, is used to output an AC signal to the electric field electrode;
[0007] A first insulating layer is provided on the surface of the first electrode facing the electrode to be dried, and / or a second insulating layer is provided on the surface of the second electrode facing the electrode to be dried.
[0008] This application integrates an electric field device into the drying apparatus, placing the electrode to be dried in an alternating electric field. The polarity of the electric field changes periodically, thus periodically changing the direction of the electric field force acting on each component particle. This achieves a relatively stable distribution of each component particle, ultimately resulting in a relatively uniform distribution of each component (conductive agent, binder, active material, and dispersant, etc.) in the thickness direction of the electrode, further improving the adhesion and cohesion of the electrode.
[0009] Furthermore, in coating and drying apparatuses, the distance between the two walls of the conveyor channels located on both sides of the thickness direction of the electrode to be dried is very small. This results in a very small distance between the first electrode and the electrode, and between the second electrode and the electrode, after the first and second electrodes are installed within the channels. Consequently, during the conveyor drying process, external factors (such as airflow disturbances in the drying gas or improper control of the electrode tension) may cause electrode vibration, leading to a short circuit between the first electrode, the electrode, and the second electrode. To address this, this application provides a first insulating layer on the first electrode and a second insulating layer on the second electrode, effectively mitigating the short circuit problem that may be caused by electrode vibration.
[0010] In some embodiments, the conveyor channel includes a first wall and a second wall, which are located on opposite sides of the thickness direction of the electrode sheet to be dried;
[0011] At least one first sliding component is provided on the first wall, and a first electrode is installed on the first sliding component. The sliding direction of the first sliding component is the same as the transmission direction of the electrode sheet to be dried.
[0012] At least one second sliding component is provided on the second wall, and a second electrode is installed on the second sliding component. The sliding direction of the second sliding component is the same as the transport direction of the electrode to be dried.
[0013] In some embodiments, a first insulating layer is provided on the surface of the first electrode facing the electrode to be dried, and / or a second insulating layer is provided on the surface of the second electrode facing the electrode to be dried.
[0014] In some embodiments, the first electrode is provided with at least one first opening, one end of which opens toward the electrode to be dried; and / or, the second electrode is provided with at least one second opening, one end of which opens toward the electrode to be dried.
[0015] In some embodiments, the spacing between adjacent first openings on the first electrode is 5mm-15mm; the spacing between adjacent second openings on the second electrode is 5mm-15mm.
[0016] In some embodiments, the radius of the first opening is 0.5mm-1.5mm; and / or, the radius of the second opening is 0.5mm-1.5mm.
[0017] In some implementations, the current collector of the electrode to be dried serves as the second electrode, and the output terminal of the AC signal module is electrically connected to the first electrode and the current collector, respectively.
[0018] In some implementations, the AC signal module includes a signal generation submodule and a power amplification submodule;
[0019] The signal generation submodule has its output connected to the input of the power amplifier submodule and is used to generate AC signals based on control signals.
[0020] The power amplifier submodule, whose output is connected to the electric field electrode, is used to amplify the AC signal and apply it to the electric field electrode.
[0021] In some embodiments, the drying device further includes a power supply module, a frequency regulation module, and an electric field strength regulation module, wherein the electric field strength regulation module includes a voltage regulation submodule and an electrode spacing regulation submodule.
[0022] The power module is used to provide operating power to the AC signal module;
[0023] The frequency adjustment module is connected to the AC signal module and is used to send frequency control signals to the AC signal module.
[0024] The voltage regulation submodule, connected to the AC signal module, is used to send voltage amplitude control signals;
[0025] The electrode spacing adjustment submodule is connected to the electric field electrode and is used to adjust the physical distance between the first electrode and the second electrode.
[0026] The second aspect of this application provides a battery production system, including the drying apparatus provided in the first aspect above.
[0027] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description
[0028] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:
[0029] Figure 1 This is a partial structural schematic diagram of a drying apparatus according to one embodiment of this application.
[0030] Figure 2 This is a partial structural schematic diagram of a drying apparatus according to one embodiment of this application.
[0031] Figure 3 This is a partial structural schematic diagram of a drying apparatus according to one embodiment of this application.
[0032] Figure 4 This is a schematic diagram of the electric field electrode structure according to one embodiment of this application.
[0033] Figure 5This is a partial structural schematic diagram of a drying apparatus according to one embodiment of this application.
[0034] Figure 6 This is a schematic diagram of the circuit control structure according to one embodiment of this application.
[0035] Figure 7 This is a schematic diagram of the battery production system structure according to one embodiment of this application.
[0036] Explanation of reference numerals in the attached figures:
[0037] 1 First wall; 2 Second wall; 3 First electrode; 4 Second electrode; 5 First sliding assembly; 6 Second sliding assembly; 7 First insulating layer; 8 Second insulating layer; 9 First opening; 10 Second opening; 11 Current collector; 12 Slurry coating; 13 Electric field electrode.
[0038] 100 AC signal module; 101 signal generation submodule; 102 power amplification submodule; 200 power supply module; 300 frequency adjustment module; 400 electric field strength adjustment module; 401 voltage adjustment submodule; 402 electrode spacing adjustment submodule; 500 electric field strength acquisition module.
[0039] 1000 drying oven; 2000 coating unit. Detailed Implementation
[0040] The embodiments of the technical solution of this application are described in detail below. The following embodiments are only used to illustrate the technical solution of this application more clearly, and are therefore only examples, and should not be used to limit the scope of protection of this application.
[0041] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.
[0042] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.
[0043] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.
[0044] Currently, wet coating is one of the important processes for preparing battery electrodes. Taking the preparation of lithium-ion battery electrodes as an example, the following steps illustrate the process: 1) Positive electrode sheets can be prepared as follows: Components used to prepare the positive electrode sheet, such as positive active materials, conductive agents, binders, and any other components, are dispersed in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; the positive electrode slurry is coated onto a positive current collector to form a slurry coating; after drying, cold pressing, and other processes, the positive electrode sheet is obtained. 2) Negative electrode sheets can be prepared as follows: Components used to prepare the negative electrode sheet, such as negative active materials, conductive agents, binders, and any other components, are dispersed in a solvent (e.g., deionized water) to form a negative electrode slurry; the negative electrode slurry is coated onto a negative current collector to form a slurry coating; after drying, cold pressing, and other processes, the negative electrode sheet is obtained.
[0045] In the wet coating process, the current collector loaded with slurry coating is placed on a conveyor belt and transported within the conveyor belt channel of an oven. It is then dried by the heating structure inside the oven, achieving rapid evaporation of the solvent in the slurry coating. During solvent evaporation, binders or other particles move towards the surface of the electrode. Binder buoyancy leads to a low binder content in the bottom layer of the electrode (i.e., the side closest to the current collector), weakening the bond between the active material and the current collector, and reducing the electrode's peel strength. Binder buoyancy also causes binder to accumulate on the surface of the active material, clogging the pores of the electrode surface and hindering lithium-ion transport. Therefore, the uneven distribution of binder along the thickness direction of the electrode not only weakens the electrode's adhesion and cohesion but also hinders rapid lithium-ion migration, ultimately adversely affecting the cycle life, storage, and rate performance of the battery cell.
[0046] In the prior art, the above problems can be improved by the following methods:
[0047] 1) Electrostatic plasma and other methods are used to ablate the adhesive floating on the electrode surface. However, this cannot solve the problem of low adhesion and cohesion of the generated electrode.
[0048] 2) In the slurry of the electrode (negative electrode slurry or positive electrode slurry), in order to prevent particle aggregation, the particle surfaces of each component are usually adjusted to have the same charge to maximize the Zeta potential. Therefore, an electric field device can be integrated on the coating oven, and electric field electrodes can be set on both sides of the electrode in the thickness direction. Direct current is input to the electrode to place the electrode in the DC electric field. The electric field force is used to suppress the floating of the binder and make the binder uniformly distributed in the thickness direction of the electrode.
[0049] However, during the research, it was found that while thermogravimetric analysis of binder flotation could improve the problem, its effect on improving the binder's cohesion and bonding strength in the electrode was limited. Further investigation using scanning electron microscopy (SEM) revealed uneven distribution of other particles (such as conductive agent particles and active material particles) along the electrode's thickness direction. The study found that different slurry systems have different Zeta potentials, making it difficult to achieve identical charges. This resulted in conductive agent and active material particles carrying opposite charges to the binder particles. Under a unidirectional electric field, the electric field could balance the binder flotation force caused by solvent evaporation, improving the flotation problem. However, this also caused the conductive agent and active material particles to move unidirectionally along the electrode's thickness direction, resulting in uneven distribution of other components along the electrode's thickness. At this point, although the uniformity of the adhesive distribution in the electrode thickness direction is improved, the uneven distribution of the bonded objects (such as conductive agents, active materials, etc.) can still easily cause stress concentration in the electrode, resulting in reduced adhesion between the active material layer and the current collector, and reduced cohesion between particles inside the active material layer.
[0050] Therefore, such as Figure 1 and Figure 3 As shown, a first aspect of this application provides a drying apparatus, comprising:
[0051] The drying chamber has an internal conveyor channel for passing the electrode sheets to be dried through the drying chamber.
[0052] The electric field electrode includes a first electrode 3 and a second electrode 4; the first electrode 3 and the second electrode 4 are disposed in the conveyor channel and are located on both sides of the thickness direction of the electrode sheet to be dried.
[0053] An AC signal module 100 is provided, the output terminal of which is connected to the electric field electrode and is used to output an AC signal to the electric field electrode.
[0054] A first insulating layer 7 is provided on the surface of the first electrode 3 facing the electrode sheet to be dried, and / or a second insulating layer 8 is provided on the surface of the second electrode 4 facing the electrode sheet to be dried.
[0055] The AC signal module 100 provides an AC signal to the electric field electrodes to create an AC electric field between the first electrode 3 and the second electrode 4. During the drying process using the drying device, the electrodes are situated within the AC electric field. Furthermore, the polarities of the first electrode 3 and the second electrode 4 alternate over time within the AC electric field. As an example, the AC signal module 100 can directly utilize an AC power supply.
[0056] The electrode to be dried includes a current collector 11 and a slurry coating 12 applied to one side of the current collector 11. Thus, the first electrode 3 is located on the side of the slurry coating 12, and the second electrode 4 is located on the side of the current collector 11.
[0057] For electrode slurries (negative or positive electrode slurries), each component (such as binder, conductive agent, dispersant, and active material) is a charged particle. Furthermore, due to interparticle forces (such as van der Waals forces, electrostatic forces, solvation forces, and steric hindrance forces), the particle surfaces of the components adsorb charges. Thus, in different slurry systems, the charges carried by the particles of each component may differ. Even if efforts are made to prevent aggregation and maximize the Zeta potential, achieving identical charges for all particles is very difficult, and particles with different charges will still exist. In this embodiment, by integrating an electric field device into the drying apparatus, the electrode to be dried is placed in an alternating electric field. The polarity of the electric field changes periodically, thus periodically changing the direction of the electric field forces acting on the particle components. This maintains a relatively stable particle distribution, ultimately achieving a relatively uniform distribution of the components (conductive agent, binder, active material, and dispersant) in the thickness direction of the electrode. This facilitates the formation of a highly consistent and stable three-dimensional network structure by all components, further improving the adhesion and cohesion of the electrode.
[0058] For coating and drying apparatuses, because the distance between the two walls of the conveyor channels located on both sides of the thickness direction of the electrode to be dried is very small, the distance between the first electrode 3 and the electrode, and between the second electrode 4 and the electrode, will be very small after the first electrode 3 and the second electrode 4 are installed in the channels. Therefore, during the conveyor drying process, external factors (such as airflow disturbances of the drying gas, improper control of electrode tension, etc.) may cause the electrode to vibrate, resulting in a short circuit between the first electrode 3, the electrode, and the second electrode 4. Therefore, if... Figure 3 As shown, the embodiments of this application can effectively improve the contact short circuit problem that may be caused by electrode vibration by providing a first insulating layer 7 on the first electrode and a second insulating layer 8 on the second electrode.
[0059] As an example, the first insulating layer 7 may be one or more of epoxy resin insulating layer, silicone rubber insulating layer, polyester resin insulating layer, polyimide insulating layer, and ceramic insulating layer; the second insulating layer 8 may be one or more of epoxy resin insulating layer, silicone rubber insulating layer, polyester resin insulating layer, polyimide insulating layer, and ceramic insulating layer.
[0060] like Figure 2 As shown, in some embodiments of this application, the conveyor channel includes a first wall 1 and a second wall 2, with the first wall 1 and the second wall 2 located on both sides of the thickness direction of the electrode sheet to be dried.
[0061] At least one first sliding component 5 is provided on the first wall 1, and a first electrode 3 is installed on the first sliding component 5. The sliding direction of the first sliding component 5 is the same as the transmission direction of the electrode sheet to be dried.
[0062] At least one second sliding component 6 is provided on the second wall 2. A second electrode 4 is installed on the second sliding component 6. The sliding direction of the second sliding component 6 is the same as the transmission direction of the electrode sheet to be dried.
[0063] Different slurry systems have different parameters such as zeta potential and viscosity, which will affect the electric field force required to balance the movement of charged particles, and thus the required electric field strength will be different. For the same slurry system, when the same batch of electrodes is dried, the degree of drying of the slurry coating 12 in the front section of the conveyor channel is not as high as that in the back section. The movement resistance of charged particles is different, and the required electric field strength is also different.
[0064] The embodiments of this application, by setting a first sliding component 5 and / or a second sliding component 6, enable the first electrode 3 and / or the second electrode 4 to be movable and adjustable in distribution position, thereby reducing the number of electrodes and maximizing efficiency when dealing with different coating systems and process parameters.
[0065] The first sliding component 5 can be a commonly used sliding component. As an example, the first sliding component 5 can be a linear guide sliding component, including a guide rail, a slider, and other auxiliary rolling elements, seals, and other components; a guide rail is installed on the first wall 1 of the conveyor channel, and the extension direction of the guide rail is in the same direction as the conveyor direction of the electrode to be dried. The first electrode 3 is installed on the slider, so that the first electrode 3 slides along the guide rail with the slider.
[0066] The second sliding assembly 6 can be a commonly used sliding assembly. As an example, the second sliding assembly 6 can be a linear guide sliding assembly, including a guide rail, a slider, and other auxiliary rolling elements, seals, and other components; a guide rail is installed on the second wall 2 of the conveyor channel, and the extension direction of the guide rail is in the same direction as the conveyor direction of the electrode to be dried. The second electrode 4 is installed on the slider, so that the second electrode 4 slides along the guide rail with the slider.
[0067] In addition, the movement of the slider can be controlled by conventional automatic control or by manual control.
[0068] like Figure 4 As shown, in some embodiments of this application, the first electrode 3 is provided with at least one first opening 9, one end of the first opening 9 opening toward the electrode sheet to be dried; and / or, the second electrode 4 is provided with at least one second opening 10, one end of the second opening 10 opening toward the electrode sheet to be dried.
[0069] In this embodiment, by opening a first opening 9 on the first electrode 3 and a second opening 10 on the second electrode 4, it is beneficial to promote the upward evaporation of solvent (such as water) and improve the drying efficiency of the electrode sheet.
[0070] The first electrode 3 is a flat plate structure, with its surface direction parallel to one side of the thickness direction of the electrode to be dried. A through hole is formed in the thickness direction of the flat plate structure as a first opening 9. The second electrode 4 is a flat plate structure, with its surface direction parallel to one side of the thickness direction of the electrode to be dried. A through hole is formed in the thickness direction of the flat plate structure as a second opening 10.
[0071] In some embodiments of this application, the spacing between adjacent first openings 9 on the first electrode 3 is 5mm-15mm; the spacing between adjacent second openings 10 on the second electrode 4 is 5mm-15mm.
[0072] In this embodiment, the spacing between adjacent first openings 9 satisfies the above conditions, providing more airflow channels and facilitating better drying efficiency of the electrode. The spacing between adjacent second openings 10 also satisfies the above conditions, further improving the drying efficiency of the electrode.
[0073] like Figure 4 As shown, on the first electrode 3, the distance L between adjacent first openings 9 is 10mm; on the second electrode 4, the distance L between adjacent second openings 10 is 10mm.
[0074] In some embodiments of this application, the radius of the first opening 9 is 0.5mm-1.5mm; and / or, the radius of the second opening 10 is 0.5mm-1.5mm.
[0075] The radius of a hole has a meaning known in the art, referring to the distance from the center line connecting the center points of the inlet and outlet to the hole wall along its normal direction. As an example, for a regular cylindrical hole, it refers to the radius of the hole, that is, the straight-line distance from the center of the circle to the hole wall; for an irregular hole, it refers to the minimum distance from the center line connecting the center points of the inlet and outlet to the hole wall along its normal direction.
[0076] In this embodiment, the semi-aperture of the first opening 9 satisfies the above conditions, which is beneficial for increasing the airflow channel and thus improving the drying efficiency of the electrode. The semi-aperture of the second opening 10 also satisfies the above conditions, which is beneficial for increasing the airflow channel and thus improving the drying efficiency of the electrode.
[0077] like Figure 4 As shown, the radius d of the first opening 9 is 1 mm; the radius d of the second opening 10 is 1 mm.
[0078] like Figure 5As shown, in some embodiments of this application, the current collector 11 of the electrode to be dried serves as the second electrode 4, and the output terminal of the AC signal module is electrically connected to the first electrode 3 and the current collector 11, respectively.
[0079] In this embodiment, the current collector 11 of the electrode sheet can be directly used as the second electrode 4, and the AC signal module 100 can be directly electrically connected to the first electrode 3 and the current collector 11, which helps to reduce the number of electrodes and simplify the internal structure of the conveyor channel.
[0080] In some embodiments of this application, the AC signal module 100 includes a signal generation submodule 101 and a power amplification submodule 102;
[0081] The signal generation submodule 101 has its output terminal connected to the input terminal of the power amplifier submodule 102, and is used to generate AC signals according to the control signals.
[0082] The power amplifier submodule 102 has its output terminal connected to the electric field electrode 13, and is used to amplify the AC signal and apply it to the electric field electrode 13.
[0083] The AC signal module 100 can directly use an AC power supply; however, when using an AC power supply directly, the frequency and electric field strength of the AC battery are fixed. In this embodiment, to further improve the adjustability and applicability of the electric field, a signal generation submodule 101 and a power amplification submodule 102 are used as the AC signal module 100. The signal generation submodule 101 can generate a low-voltage AC signal, and the power amplification submodule 102 can amplify the AC signal to output a high-voltage AC signal to the electric field electrode 13. In this way, a control signal can be sent to the signal generation submodule 101 or the power amplification submodule to output an AC signal with the required electric field strength and frequency.
[0084] The signal generation submodule 101 can be a conventional signal generation module. For example, the signal generation submodule 101 can be a direct digital frequency synthesizer (DDS), a voltage-controlled oscillator (VCO), etc.
[0085] The power amplifier submodule 102 can be a conventional power amplifier module. For example, the power amplifier submodule 102 can adopt a linear amplifier circuit or a switching amplifier circuit (such as a Class D amplifier) topology.
[0086] like Figure 6 As shown, in some embodiments of this application, the drying device further includes a power supply module 200, a frequency adjustment module 300, and an electric field strength adjustment module 400. The electric field strength adjustment module includes a voltage adjustment submodule 401 and an electrode spacing adjustment submodule 402.
[0087] Power module 200 is used to provide operating power to AC signal module 100;
[0088] The frequency adjustment module 300 is connected to the AC signal module 100 and is used to send frequency control signals to the AC signal module 100.
[0089] The voltage regulation submodule 401 is connected to the AC signal module 100 and is used to send voltage amplitude control signals.
[0090] The electrode spacing adjustment submodule 402 is connected to the electric field electrode 13 and is used to adjust the physical distance between the first electrode 3 and the second electrode 4.
[0091] As an example, the power module 200 may employ an AC mains input interface and an AC-DC conversion circuit to convert external AC power into stable DC power; it may also employ a DC power interface to connect a battery or an external DC power adapter.
[0092] As an example, the frequency adjustment module 300 is connected to the signal generation submodule 101. The frequency adjustment module 300 can be a user-operated knob, numeric keypad, or communication interface (such as USB or Bluetooth). The frequency setting value generated by the module is transmitted to the signal generation submodule 101 in the form of an electrical signal or data protocol.
[0093] As an example, the voltage regulation submodule 401 is signal-connected to the signal generation submodule 101, and the voltage regulation submodule 401 indirectly controls the final output voltage by changing the amplitude of the output signal of the signal generation submodule 101. Alternatively, the voltage regulation submodule 401 is signal-connected to the power amplifier submodule 102, the signal generation submodule 101 outputs a signal of fixed amplitude, and the voltage regulation submodule 401 regulates the output voltage by directly controlling the gain of the power amplifier submodule 102.
[0094] As an example, the spacing adjustment submodule is mechanically connected to the electric field electrode 13. This can be achieved by using a sliding component (such as a lead screw and slider mechanism) to mount the first electrode 3 on the wall of the conveyor channel, so that the first electrode 3 can move along the thickness direction perpendicular to the electrode sheet to be dried. Similarly, a sliding component (such as a lead screw and slider mechanism) can be used to mount the second electrode 4 on the wall of the conveyor channel, so that the second electrode 4 can move along the thickness direction perpendicular to the electrode sheet to be dried.
[0095] By driving the sliding component to work, the first electrode 3 and the second electrode 4 are moved, thereby changing the distance between the first electrode 3 and the second electrode 4.
[0096] The electric field parameters, such as electric field strength and frequency, can be adjusted based on product performance requirements, factors affecting the migration of charged particles in the slurry coating 12, and drying process parameters. The electric field strength includes voltage and electrode spacing. By adjusting these parameters, the magnitude of the electric force on each component of the charged particles in the slurry coating 12 can be controlled, thereby promoting a more uniform distribution of each component along the electrode thickness and improving production efficiency.
[0097] As an example, factors affecting the migration of charged particles in the slurry coating 12 include slurry properties (such as viscosity, zeta potential, etc.).
[0098] As an example, drying process parameters include drying time, etc.
[0099] Furthermore, an electric field strength acquisition module 500 can be set in the electric field to acquire the current electric field strength at regular intervals or in real time, and the magnitude of the electric field strength can be adjusted based on the feedback results of the electric field strength acquisition module 500.
[0100] The second aspect of this application provides a battery production system including the drying apparatus described in the first aspect above.
[0101] In this embodiment of the application, the battery production system includes the aforementioned drying device and has the beneficial effects of the aforementioned drying device, which will not be described in detail here.
[0102] The electrode drying apparatus described in this application is applicable to battery production systems. For example... Figure 7 As shown, the battery production system includes a coating device 2000 and an oven 1000. The coating device 2000 is used to coat a slurry onto a current collector to form an electrode sheet. The oven 1000 is an oven provided in any of the above embodiments and is used to dry the electrode sheet.
[0103] In the several embodiments provided in this application, it should be understood that the disclosed systems and devices (such as ovens) can be implemented in other ways. For example, the device embodiments described above are merely illustrative; for instance, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple single modules or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interfaces, devices, or units, and may be electrical, mechanical, or other forms.
[0104] In addition, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.
[0105] To make the technical problems, technical solutions, and beneficial effects solved by the embodiments of this application clearer, the following will provide a more detailed description in conjunction with the embodiments and accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its applications. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0106] Example 1
[0107] (1) Oven
[0108] The oven structure integrating an alternating electric field is used, such as Figure 1 As shown, the drying chamber has a conveyor belt channel for transporting the electrode sheets to be dried. The conveyor belt channel includes a first wall 1 and a second wall 2. The first wall 1 is opposite to one side of the electrode sheet to be dried along its thickness direction, and the second wall 2 is opposite to the other side of the electrode sheet to be dried along its thickness direction. A first electrode 3 is disposed on the first wall 1, and a second electrode 4 is disposed on the second wall 2. The AC signal module 100 uses an AC power supply, and its output terminal is electrically connected to the electric field electrode 13 to output an AC signal to the electric field electrode 13, thereby forming an AC electric field between the first electrode 3 and the second electrode 4.
[0109] (2) Preparation of negative electrode sheet:
[0110] 1) A negative electrode slurry was prepared by adding graphite (the negative electrode active material), SP (the conductive agent), sodium carboxymethyl cellulose (CMC-Na) (the dispersant), and styrene-butadiene rubber (SBR) (the binder) to water at a mass ratio of 96.0:0.5:1.5:2.0. The viscosity of the negative electrode slurry was 6215 cps. Furthermore, in the negative electrode slurry, the binder SBR carried a positive charge, the dispersant CMC-Na carried a negative charge, and the active material graphite carried a negative charge through adsorption of the dispersant. This can be analyzed using a Zeta potential test (instrument model: Malvern Panalytical Zetasizer Nano ZS). The negative electrode slurry was coated onto both sides of the copper foil of the negative electrode current collector to form a slurry coating. The coating thickness on one side was 160 mg / 1450.25 cm². -2 .
[0111] 2) Dry the current collector of the coated negative electrode slurry in an oven.
[0112] The drying parameters are set as follows: drying temperature is 95℃, and drying time is 60s.
[0113] The oven structure using an integrated electric field device is as follows: Figure 1 As shown, the AC electric field parameters are set as follows: AC voltage is 110V, frequency is 50 Hz, the distance between the first electrode and the second electrode is fixed at 50 mm, and the electric field is applied for 60s.
[0114] 3) After the slurry coating is dried, a negative electrode active material layer is formed. Then, after cold pressing and cutting, a negative electrode sheet is obtained. The compaction density of the negative electrode sheet is 1.55 g / cm³. -3 .
[0115] Comparative Example 1
[0116] Preparation of negative electrode sheet:
[0117] 1) A negative electrode slurry was prepared by adding graphite (anode active material), SP (conductive agent), sodium carboxymethyl cellulose (CMC-Na) (dispersant), and styrene-butadiene rubber (SBR) (binder) to water at a mass ratio of 96.0:0.5:1.5:2.0. The viscosity of the negative electrode slurry was 6215 cps. The negative electrode slurry was coated on both sides of the copper foil current collector to form a slurry coating. The coating weight on one side was 160 mg / 1450.25 cm⁻¹. -2 .
[0118] 2) Dry the current collector of the coated negative electrode slurry in an oven.
[0119] The drying parameters are set as follows: drying temperature is 95℃, and drying time is 60s.
[0120] No electric field was set up.
[0121] 3) After the slurry coating is dried, a negative electrode active material layer is formed. Then, after cold pressing and cutting, a negative electrode sheet is obtained. The compaction density of the negative electrode sheet is 1.55 g / cm³. -3 .
[0122] Comparative Example 2
[0123] (1) Drying oven:
[0124] As shown in Embodiment 1, the difference is that the AC signal module 100 is replaced with an AC power supply and a rectifier. The output terminal of the AC power supply is connected to the input terminal of the rectifier, and the output terminal of the rectifier is connected to the electric field electrode 13 (i.e., the first electrode 3 and the second electrode 4). The AC power supply is converted into DC power supply through the rectifier, and then the DC power supply outputs a DC signal to the electric field electrode 13, forming a DC electric field between the first electrode 3 and the second electrode 4.
[0125] (2) Preparation of negative electrode sheet:
[0126] 1) A negative electrode slurry was prepared by adding graphite (anode active material), SP (conductive agent), sodium carboxymethyl cellulose (CMC-Na) (dispersant), and styrene-butadiene rubber (SBR) (binder) to water at a mass ratio of 96.0:0.5:1.5:2.0. The viscosity of the negative electrode slurry was 6215 cps. The negative electrode slurry was then coated onto both sides of the copper foil current collector to form a slurry coating with a single-sided coating thickness of 160 mg / 1450.25 cm². -2 .
[0127] 2) Dry the current collector of the coated negative electrode slurry in an oven.
[0128] The drying parameters are set as follows: drying temperature is 95℃, and drying time is 60s.
[0129] The DC electric field parameters are set as follows: AC voltage is 110V, the distance between the first and second electrodes is fixed at 50mm, and the electric field is applied for 60s.
[0130] 3) After the slurry coating is dried, a negative electrode active material layer is formed. Then, after cold pressing and cutting, a negative electrode sheet is obtained. The compaction density of the negative electrode sheet is 1.55 g / cm³. -3 .
[0131] The negative electrode sheets obtained in Example 1, Comparative Example 1 and Comparative Example 2 were subjected to performance tests, and the test results are shown in Table 1.
[0132] Table 1
[0133]
[0134] As shown in Table 1, compared with Comparative Example 1 and Comparative Example 2, the electrode obtained by using AC electric field treatment in Example 1 of this application exhibits higher adhesion and cohesion, indicating that the components in the active material layer of the electrode are more evenly distributed.
[0135] [Performance Testing Methods]
[0136] 1. Testing of adhesion strength:
[0137] Test indicator: peel strength.
[0138] Instrument: Instron 3365 tensile testing machine.
[0139] Method: The adhesion of the electrode was tested using a universal testing machine with a 90° peel method.
[0140] Detailed steps for peel strength (adhesion): Fix the electrode to the stainless steel sheet with double-sided tape, fix one end of the electrode with a clamp, and test the adhesion by peeling at 90°.
[0141] 2. Cohesive strength testing:
[0142] Test indicator: Film strength.
[0143] Instrument: Instron 3365 tensile testing machine.
[0144] Method: The cohesive force of the electrode was tested by peeling it at 90° using a universal testing machine.
[0145] Detailed steps for film strength (cohesion): Fix the electrode to the stainless steel sheet with double-sided tape, then apply adhesive to the electrode again. Fix one end of the tape on the upper surface of the electrode with a clamp and test the cohesion by peeling at 90°.
[0146] The greater the peel strength, the greater the film-forming strength (cohesion) of the positive electrode active layer or the greater the adhesion to the film-forming substrate (such as aluminum foil).
[0147] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.
Claims
1. A drying apparatus, characterized in that, include: The drying chamber has an internal conveyor channel for passing the electrode sheets to be dried through the drying chamber. The electric field electrode includes a first electrode and a second electrode; the first electrode and the second electrode are disposed in the conveyor channel and are respectively located on both sides of the thickness direction of the electrode sheet to be dried; An AC signal module, the output terminal of which is connected to the electric field electrode, is used to output an AC signal to the electric field electrode; A first insulating layer is provided on the surface of the first electrode facing the electrode to be dried, and / or a second insulating layer is provided on the surface of the second electrode facing the electrode to be dried.
2. The drying apparatus according to claim 1, characterized in that, The conveyor channel includes a first wall and a second wall, which are located on opposite sides of the thickness direction of the electrode sheet to be dried. At least one first sliding component is provided on the first wall, and the first electrode is mounted on the first sliding component. The sliding direction of the first sliding component is the same as the transmission direction of the electrode sheet to be dried. The second wall is provided with at least one second sliding component, on which the second electrode is mounted, and the sliding direction of the second sliding component is the same as the transmission direction of the electrode to be dried.
3. The drying apparatus according to claim 1 or 2, characterized in that, The first electrode is provided with at least one first opening, and one end of the first opening faces the electrode sheet to be dried; And / or, the second electrode is provided with at least one second opening, one end of the second opening facing the electrode to be dried.
4. The drying apparatus according to claim 3, characterized in that, On the first electrode, the spacing between adjacent first openings is 5mm-15mm; on the second electrode, the spacing between adjacent second openings is 5mm-15mm.
5. The drying apparatus according to claim 3, characterized in that, The radius of the first opening is 0.5mm-1.5mm; and / or the radius of the second opening is 0.5mm-1.5mm.
6. The drying apparatus according to claim 1 or 2, characterized in that, The current collector of the electrode to be dried serves as the second electrode, and the output terminal of the AC signal module is electrically connected to the first electrode and the current collector, respectively.
7. The drying apparatus according to claim 1 or 2, characterized in that, The AC signal module includes a signal generation submodule and a power amplification submodule; The signal generation submodule has its output terminal connected to the input terminal of the power amplification submodule, and is used to generate an AC signal according to the control signal; The power amplifier submodule has its output terminal connected to the electric field electrode, and is used to amplify the AC signal and apply it to the electric field electrode.
8. The drying apparatus according to claim 1 or 2, characterized in that, The drying device also includes a power supply module, a frequency adjustment module, and an electric field strength adjustment module. The electric field strength adjustment module includes a voltage adjustment submodule and an electrode spacing adjustment submodule. The power module is used to provide operating power to the AC signal module; The frequency adjustment module is connected to the AC signal module and is used to send frequency control signals to the AC signal module; The voltage regulation submodule is connected to the AC signal module and is used to send voltage amplitude control signals; The electrode spacing adjustment submodule is connected to the electric field electrode and is used to adjust the physical distance between the first electrode and the second electrode.
9. A battery production system, characterized in that, The drying apparatus includes any one of claims 1 to 8.