Apparatus for drying electrode sheet for secondary battery and method therefor

Abstract

The present invention relates to an apparatus for drying an electrode sheet for a secondary battery and a method therefor and, more specifically, to: an apparatus for drying an electrode sheet, the apparatus using an intense pulsed light (IPL) composed of a xenon lamp and a filter to dry an active material for a secondary battery, wherein parameters of the IPL are controlled on the basis of the mass transfer resistance (moisture, temperature, airflow, etc.) sensed inside the drying apparatus, thereby mitigating binder migration and reducing drying time; and a method therefor.

Description

Drying apparatus for electrode sheets for secondary batteries and method thereof

[0001] The present invention relates to a drying apparatus and method for an electrode sheet for a secondary battery, and more specifically, to a drying apparatus and method for an electrode sheet for a secondary battery that can improve binder migration and shorten drying time by using an Intense Pulsed Light (IPL) composed of a xenon lamp and a filter to dry an active material for a secondary battery, and controlling the parameters of the IPL based on mass transfer resistance (moisture, temperature, air flow, etc.) detected within the drying apparatus.

[0002] Recently, interest in energy storage technology has been steadily increasing. As application fields expand to include energy for mobile phones, camcorders, and laptop PCs, and even electric vehicles, efforts in the research and development of electrochemical devices are becoming increasingly concrete.

[0003] Electrochemical devices are the field receiving the most attention in this regard, and among them, the development of rechargeable secondary batteries is the focus of interest. Recently, research and development in developing such batteries is proceeding with the design of new electrodes and batteries to improve capacity density and specific energy.

[0004] Figure 1 is a diagram illustrating the electrode process of a general secondary battery.

[0005] The electrode process, which is the process of making the positive and negative electrodes that form the basis of the battery, consists of a mixing process (10), a coating process (20), a roll pressing process (30), and a slitting and notching process (40).

[0006] The mixing process (10) is a process of mixing active materials to produce a slurry.

[0007] The above mixing process (10) is a step of making a slurry by weighing and mixing various raw materials required to make the anode and cathode. To make the slurry, a binder is added to increase the adhesion between particles of the electrode active material. Then, a conductive material responsible for the movement of electrons between the active materials is added.

[0008] The coating process (20) is a process of thinly coating the slurry onto the current collector.

[0009] In the coating process (20) above, the positive and negative electrode slurries generated in the mixing process (10) are thinly coated onto aluminum foil and copper foil, respectively. Then, the coated electrodes are dried in a hot air oven at a temperature of 100°C or higher. Through this process, the performance and lifespan of the battery are improved.

[0010] The roll pressing process (30) is a process of spreading the electrode evenly.

[0011] The above roll pressing process (30) is also called a rolling process and flattens the electrode by passing it between two rolls. As the large rolls make the electrode thinner and increase its density, the bonding strength between the electrode surface and the active material increases. At this time, the movement of lithium ions between the electrode and the active material becomes smooth, thereby improving the output and performance of the battery.

[0012] The slitting and notching process (40) is a process of cutting the electrode to fit the battery size.

[0013] The electrode, which has been flattened through the roll pressing process (30) described above, undergoes a slitting and notching process (40) to cut it to the size of the battery. The slitting and notching process (40) is divided into two stages: first, a slitting process is performed to cut the electrode in the vertical direction according to the battery design specifications, and then a notching process is performed to cut it horizontally to create V-grooves and tabs to create positive (+) terminal and negative (-) terminal electrodes. In the notching process, if a portion for grounding the tab is left in the 'uncoated area,' which is an empty space where the positive / negative active material is not coated, the remaining portion is cut using a notching device.

[0014] However, the bottleneck in manufacturing the electrode sheet for the secondary battery is the drying process section within the coating process (20). If the drying time of the conventional hot air drying process is shortened, not only does a problem with the adhesive performance occur where the binder and the film separate, but the dispersibility of the active material is also affected due to binder migration.

[0015] Even if an electrode slurry is used that is evenly dispersed and mixed in a solvent or binder, if the electrode slurry aggregates or localizes due to film shrinkage or binder migration during the drying process, the power capacity or cycle performance may be significantly degraded.

[0016] Conventional hot-air drying processes have limitations in ensuring quality and productivity by improving binder migration and reducing drying time.

[0017] Korean published patent [10-2024-0000298] discloses a hybrid drying system for manufacturing secondary battery electrodes.

[0018] Korean registered patent [10-2471250] discloses an apparatus and method for uniformly treating powder materials using IPL.

[0019] Accordingly, the present invention has been devised to solve the problems described above. The objective of the present invention is to provide a drying apparatus and method for an electrode sheet for a secondary battery that can improve binder migration and shorten drying time by drying an active material for a secondary battery using an Intense Pulsed Light (IPL) composed of a xenon lamp and a filter, and controlling the parameters of the IPL based on the mass transfer resistance (moisture, temperature, air flow, etc.) detected within the drying apparatus.

[0020] The purposes of the embodiments of the present invention are not limited to those mentioned above, and other unmentioned purposes will be clearly understood by those skilled in the art from the description below.

[0021] A drying device for an electrode sheet for a secondary battery according to an embodiment of the present invention for achieving the above-described purpose comprises: an Intense Pulsed Light (IPL) (100) equipped with at least one xenon lamp and irradiating light into a preset drying space; an exhaust unit (200) through which external air is introduced into the drying space and internal air of the drying space is discharged to the outside; a sensor unit (300) for measuring the temperature of the electrode sheet and the humidity of the drying space in real time; and a control unit (400) for controlling parameters of the IPL based on the temperature of the electrode sheet and the humidity of the drying space measured by the sensor unit.

[0022] The above IPL is characterized by comprising: a xenon lamp (101) that generates light having a wavelength of 400 nm to 1200 nm; and a reflector (102) provided on one side of the xenon lamp to direct the generated light into the drying space, and the xenon lamp is characterized by having at least one filter for determining the wavelength of the light to be irradiated.

[0023] The above IPL is characterized by having at least two xenon lamps arranged in parallel along the direction in which the electrode sheet moves and irradiating light of different wavelengths, and arranged such that the wavelength of the light irradiated from the xenon lamps decreases along the direction from the entrance side of the drying space into which the electrode sheet enters to the exit side of the drying space.

[0024] The above electrode sheet is characterized by being equipped with a xenon lamp that generates light of 1000 nm or more at the entrance side of the drying space into which it enters.

[0025] The above parameters are characterized by including the intensity and power of the pulse generated in the IPL, the duration of the pulse, and the repetition period of the pulse.

[0026] The exhaust unit (200) is characterized by including an inlet through which external air is introduced, an outlet through which internal air of the drying space is discharged, and a housing, and further comprises a moisture filter (201) for removing moisture in the inlet.

[0027] The exhaust unit (200) is further characterized by having a measuring sensor (202) for measuring solvent concentration and humidity around the discharge port.

[0028] The above parameters are characterized by including the intensity and power of the pulse generated in the IPL, the duration of the pulse, and the repetition period of the pulse, and the control unit (400) is characterized by controlling the parameters of the IPL based on the solvent concentration measured by the measurement sensor and the humidity on the outlet side.

[0029] In addition, a drying method for an electrode sheet for a secondary battery, which is executed in the form of a program by a computational processing means including a computer according to an embodiment of the present invention for achieving the above-mentioned purpose, comprises: a drying step (S10) of drying an electrode sheet for a secondary battery transferred to a drying space using an IPL that generates a preset wavelength; a measurement step (S20) of measuring the temperature of the electrode sheet for a secondary battery transferred to the drying space and the humidity of the drying space in real time at a sensor unit; and a parameter control step (S30) of controlling parameters of the IPL based on the temperature of the electrode sheet and the humidity of the drying space measured at the measurement step at a control unit, wherein the parameters include the intensity and power of the pulse generated by the IPL, the duration of the pulse, and the repetition period of the pulse.

[0030] The drying method for the electrode sheet for the secondary battery described above is characterized by further including: a second measurement step (S40) for measuring the concentration of a solvent and the humidity on the discharge side; and a second parameter control step (S50) for controlling the parameters of the IPL based on the measured solvent concentration and the humidity on the discharge side in the control unit.

[0031] In addition, according to one embodiment of the present invention, a computer-readable recording medium is provided that stores a program for implementing a drying method for an electrode sheet for a secondary battery.

[0032] In addition, according to one embodiment of the present invention, a program stored in a computer-readable recording medium is provided to implement a drying method for the electrode sheet for the secondary battery.

[0033] According to the drying apparatus and method for an electrode sheet for a secondary battery according to one embodiment of the present invention, an active material for a secondary battery is dried using an Intense Pulsed Light (IPL) composed of a xenon lamp and a filter, and by controlling the parameters of the IPL based on the mass transfer resistance (moisture, temperature, air flow, etc.) detected within the drying apparatus, the effect is to improve binder migration and shorten the drying time.

[0034] In addition, according to the drying apparatus and method for a secondary battery electrode sheet according to one embodiment of the present invention, by using an IPL equipped with a plurality of xenon lamps arranged in parallel having different wavelengths, the electrode sheet having a thickness of several to several hundred micrometers is dried from the inside outward direction (surface direction), thereby preventing the re-adsorption of moisture due to capillary action caused by the microstructure (pores) of the electrode slurry, and thus the effect of improving quality is achieved.

[0035] Figure 1 is a diagram illustrating the electrode process of a general secondary battery.

[0036] FIG. 2 is a block diagram of a drying apparatus for an electrode sheet for a secondary battery according to one embodiment of the present invention.

[0037] FIG. 3 is an exemplary drawing for explaining the IPL of FIG. 2.

[0038] FIG. 4 is another embodiment drawing for explaining the IPL of FIG. 2.

[0039] FIG. 5 is a configuration diagram of a drying device for an electrode sheet for a secondary battery according to one embodiment of the present invention.

[0040] FIG. 6 is a flowchart of an embodiment of a drying method for an electrode sheet for a secondary battery according to the present invention.

[0041] *Detailed explanation of the main symbols in the drawing*

[0042] 100: IPL 200: Exhaust section

[0043] 300: Sensor unit 400: Control unit

[0044] 101: Xenon lamp 102: Reflector

[0045] 201: Moisture filter 202: Measurement sensor

[0046] 301: Aluminum foil or copper foil 302: Anode material or cathode material

[0047] 401: Ramp housing 402: Connection part

[0048] 501: Transfer roller

[0049] S10: Drying stage

[0050] S20: Measurement stage

[0051] S30: Control stage

[0052] S40: Second measurement step

[0053] S50: Second control step

[0054] The present invention is capable of various modifications and may have various embodiments, and specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the invention to specific embodiments, and it should be understood that the invention includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention.

[0055] When it is stated that one component is "connected" or "joined" to another component, it should be understood that while it may be directly connected or joined to that other component, there may also be other components in between.

[0056] On the other hand, when it is stated that one component is "directly connected" or "directly coupled" to another component, it should be understood that there are no other components in between.

[0057] The terms used in this specification are used merely to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, terms such as “comprising” or “having” are intended to specify the existence of the features, numbers, processes, operations, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, processes, operations, components, parts, or combinations thereof.

[0058] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application.

[0059] The present invention will be described in more detail below with reference to the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings. Based on the principle that the inventor can appropriately define the concepts of terms to best describe their invention, they should be interpreted in a meaning and concept consistent with the technical spirit of the present invention. Furthermore, unless otherwise defined, technical and scientific terms used shall have the meaning commonly understood by those skilled in the art to which this invention pertains. Descriptions of known functions and configurations that could unnecessarily obscure the essence of the present invention in the following description and attached drawings are omitted. The drawings presented below are provided as examples to ensure that the spirit of the present invention is sufficiently conveyed to those skilled in the art. Accordingly, the present invention is not limited to the drawings presented below and may be embodied in other forms. Additionally, throughout the specification, the same reference numerals indicate the same components. It should be noted that the same components in the drawings are represented by the same reference numerals wherever possible.

[0060] FIG. 2 is a block diagram of a drying device for an electrode sheet for a secondary battery according to one embodiment of the present invention, FIG. 3 is a diagram of one embodiment for explaining the IPL of FIG. 2, FIG. 4 is a diagram of another embodiment for explaining the IPL of FIG. 2, and FIG. 5 is a configuration diagram of a drying device for an electrode sheet for a secondary battery according to one embodiment of the present invention.

[0061] As illustrated in FIG. 2, a drying device for an electrode sheet for a secondary battery according to one embodiment of the present invention includes an Intense Pulsed Light (IPL) (100), an exhaust unit (200), a sensor unit (300), and a control unit (400).

[0062] The above IPL (100) is equipped with at least one xenon lamp and irradiates light into a preset drying space.

[0063] The exhaust unit (200) allows external air to flow into the drying space and internal air of the drying space to be discharged to the outside.

[0064] The sensor unit (300) measures the temperature of the electrode sheet and the humidity of the drying space in real time and transmits them to the control unit (400).

[0065] The control unit (400) controls the parameters of the IPL based on the temperature of the electrode sheet and the humidity of the drying space measured by the sensor unit (300).

[0066] The above parameters include the intensity and power of the pulse generated in the IPL, the duration of the pulse, and the repetition period of the pulse.

[0067] As illustrated in FIG. 3, the IPL includes a xenon lamp (101) that generates light having a wavelength of 400 nm to 1200 nm, and a reflector (102) provided on one side of the xenon lamp (101) to direct the generated light into the drying space (303).

[0068] The electrode sheet is in a state where an anode material or a cathode material (active material) (302) is applied on an aluminum foil or a copper foil (301), such that an anode material is applied on the aluminum foil and a cathode material is applied on the copper foil.

[0069] The above xenon lamp (101) is equipped with at least one filter for determining the wavelength of light to be irradiated.

[0070] Then, only light of the desired wavelength from the light generated from the xenon lamp (101) is irradiated into the drying space (303), and since the light is collected through the reflector (102), a focus line (304) is formed on the anode material or cathode material (302).

[0071] As the above aluminum foil or copper foil (301) is transported by the transport roller, the electrode sheet is dried as the focus line moves.

[0072] As shown in FIG. 4, the IPLs are arranged in parallel along the direction in which the electrode sheet moves.

[0073] The above IPL is equipped with at least two xenon lamps (101) that irradiate light of different wavelengths.

[0074] A lamp housing (401) having a reflector integrally provided on the upper (one side) of the above xenon lamp (101) is provided, and a connecting part (402) is connected to each xenon lamp (101) and a utility such as a power source or a cooler.

[0075] In the drying process, the control unit (400) controls and manages the parameters of the IPL (pulse intensity / power, pulse duration, pulse repetition period, etc.) according to the measured mass transfer resistance (moisture content, temperature, air inflow and outflow, etc.).

[0076] If the pulse intensity or pulse power is applied excessively, expansion, cracking, or delamination of the electrode sheet may occur, so it is very important to control the IPL parameters. In addition, environmental conditions such as moisture content, temperature, and air inflow and outflow must be sensed to manage whether the drying process is being carried out properly.

[0077] FIG. 5 shows a drying device for an electrode sheet for a secondary battery according to an embodiment of the present invention, configured and arranged in the block diagram of FIG. 2.

[0078] The IPL (100) illustrated in FIG. 5 is equipped with a plurality of xenon lamps, which can be arranged such that the wavelength of light irradiated from the xenon lamps decreases along the direction from the entrance side of the drying space into which the electrode sheet enters to the exit side of the drying space.

[0079] The electrode sheet is moved from the entrance of the drying space to the exit side of the drying space by the transfer roller (501).

[0080] A xenon lamp generating light of 1000 nm or more may be provided at the entrance side of the drying space into which the electrode sheet is introduced.

[0081] That is, by using an IPL equipped with multiple xenon lamps arranged in parallel having different wavelengths, the irradiated wavelengths are arranged in order from long wavelength to short wavelength, so the electrode sheet with a thickness of several to several hundred micrometers can be dried sequentially from deep to shallow along the surface direction in the deepest part (inside).

[0082] Accordingly, the re-adsorption of moisture due to capillary action caused by the microstructure (pores) of the electrode slurry can be prevented, thereby improving quality.

[0083] Meanwhile, the exhaust unit (200) may include an inlet for external air to enter, an outlet for internal air of the drying space to be discharged, and a housing.

[0084] Since it is a drying device, the inlet may further be equipped with a moisture filter (201) for removing moisture contained in the outside air.

[0085] Additionally, the exhaust unit (200) may further be equipped with a measuring sensor (202) for measuring solvent concentration and humidity around the discharge port.

[0086] Accordingly, the control unit (400) can control the parameters of the IPL based on the solvent concentration measured by the measurement sensor (202) and the humidity on the outlet side.

[0087] The location and size of the inlet, outlet, and housing of the exhaust unit (200) shown in FIG. 5 are illustrated as examples, and each component can perform the same function even if it has a different location, different shape, and different size.

[0088] FIG. 6 is a flowchart of an exemplary embodiment of a drying method for an electrode sheet for a secondary battery according to the present invention.

[0089] First, the drying method for a secondary battery electrode sheet according to the present invention dries the secondary battery electrode sheet, which is transferred to a drying space, using an IPL that generates a preset wavelength (S10).

[0090] The above IPL is equipped with a plurality of xenon lamps, arranged so that the wavelength of light irradiated from the xenon lamps decreases along the direction from the inlet side of the drying space into which the electrode sheet enters to the outlet side of the drying space.

[0091] At this time, the sensor unit (300) measures the temperature of the electrode sheet for the secondary battery being transferred to the drying space and the humidity of the drying space in real time (S20).

[0092] Then, the control unit (400) controls the parameters of the IPL based on the temperature of the electrode sheet and the humidity of the drying space measured in the measurement step (S20) (S30).

[0093] At this time, the above parameters include the intensity and power of the pulse generated in the IPL, the duration of the pulse, and the repetition period of the pulse.

[0094] The drying method for an electrode sheet for a secondary battery according to the present invention may further include a second measurement step (S40) for measuring the concentration of a solvent and the humidity on the discharge side, and a second parameter control step (S50) for controlling the parameters of the IPL based on the measured solvent concentration and the humidity on the discharge side in the control unit (400).

[0095] Although the drying step (S10), measurement step (S20), parameter control step (S30), second measurement step (S40), and second parameter control step (S50) have been described above as proceeding in order, the present invention is not limited thereto, and it is also possible for each step to be performed simultaneously in parallel.

[0096] Although a drying method for an electrode sheet for a secondary battery according to one embodiment of the present invention has been described above, it is obvious that a computer-readable recording medium storing a program for implementing the drying method for an electrode sheet for a secondary battery and a program stored in the computer-readable recording medium for implementing the drying method for an electrode sheet for a secondary battery can also be implemented.

[0097] That is, those skilled in the art will readily understand that the drying method for an electrode sheet for a secondary battery described above may be provided by being tangibly implemented as a program of instructions for implementing it, and included in a computer-readable recording medium. In other words, it may be implemented in the form of program instructions that can be executed through various computer means and recorded on a computer-readable recording medium. The computer-readable recording medium may include program instructions, data files, data structures, etc., either individually or in combination. The program instructions recorded on the computer-readable recording medium may be those specifically designed and configured for the present invention, or they may be those known and available to those skilled in computer software. Examples of the computer-readable recording medium include magnetic media such as hard disks, floppy disks, and magnetic tapes; optical recording media such as CD-ROMs and DVDs; magneto-optical media such as floptical disks; and hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, flash memory, and USB memory. Examples of program instructions include machine code, such as that generated by a compiler, as well as high-level language code that can be executed by a computer using an interpreter, etc. The hardware device may be configured to operate as one or more software modules to perform the operation of the present invention, and vice versa.

[0098] The present invention is not limited to the embodiments described above, and its scope of application is diverse. Furthermore, it is understood that various modifications are possible without departing from the essence of the invention as claimed in the claims.

Claims

1. In a drying device for an electrode sheet for a secondary battery, Intense Pulsed Light (IPL; 100) equipped with at least one xenon lamp and irradiating light into a preset drying space; An exhaust section (200) through which external air flows into the drying space and internal air of the drying space is discharged to the outside; A sensor unit (300) for measuring the temperature of the electrode sheet and the humidity of the drying space in real time; A control unit (400) for controlling parameters of the IPL based on the temperature of the electrode sheet measured by the sensor unit and the humidity of the drying space. Drying device for electrode sheets for secondary batteries including 2. In Paragraph 1, The above IPL is, A xenon lamp (101) that generates light having a wavelength of 400 nm to 1200 nm; and A reflector (102) provided on one side of the above xenon lamp to direct light generated into the drying space Characterized by including, The above xenon lamp is, A drying device for an electrode sheet for a secondary battery, characterized by having at least one filter for determining the wavelength of light to be investigated.

3. In Paragraph 2, The above IPL is, The electrode sheet is arranged in parallel along the direction of movement and is equipped with at least two xenon lamps that irradiate light of different wavelengths, and A drying device for a secondary battery electrode sheet, characterized in that the wavelength of light irradiated from the xenon lamp is reduced along the direction from the inlet side of the drying space into which the electrode sheet is introduced to the outlet side of the drying space.

4. In Paragraph 3, A drying device for an electrode sheet for a secondary battery, characterized in that a xenon lamp generating light of 1000 nm or more is provided at the entrance side of the drying space into which the electrode sheet is introduced.

5. In Paragraph 1, The above parameters are, A drying device for an electrode sheet for a secondary battery, characterized by including the intensity and power of the pulse generated in the above IPL, the duration of the pulse, and the repetition period of the pulse.

6. In Paragraph 1, The above exhaust section (200) is, It is characterized by including an inlet for external air to be introduced, an outlet for internal air of the drying space to be discharged, and a housing. A drying device for a secondary battery electrode sheet, characterized by further including a moisture filter (201) for removing moisture in the above-mentioned inlet.

7. In Paragraph 6, The above exhaust section (200) is, A drying device for an electrode sheet for a secondary battery, characterized by further having a measuring sensor (202) for measuring solvent concentration and humidity around the above-mentioned discharge port.

8. In Paragraph 7, The above parameters are, It is characterized by including the intensity and power of the pulse generated in the above IPL, the duration of the pulse, and the repetition period of the pulse, and The above control unit (400) is, A drying device for an electrode sheet for a secondary battery, characterized by controlling parameters of the IPL based on the solvent concentration measured by the measurement sensor and the humidity on the discharge side.

9. A method for drying an electrode sheet for a secondary battery, comprising a program executed by a computational processing means including a computer, wherein A drying step (S10) of drying an electrode sheet for a secondary battery transferred to a drying space using an IPL that generates a preset wavelength; A measurement step (S20) for measuring the temperature of an electrode sheet for a secondary battery being transferred to a drying space and the humidity of the drying space in real time in a sensor unit; and A parameter control step (S30) in the control unit, which controls the parameters of the IPL based on the temperature of the electrode sheet and the humidity of the drying space measured in the measurement step. Includes, The above parameters are, A drying method for an electrode sheet for a secondary battery, characterized by including the intensity and power of a pulse generated in the above IPL, the duration of the pulse, and the repetition period of the pulse.

10. In Paragraph 9, A second measurement step (S40) for measuring the concentration of the solvent and the humidity on the discharge side; and In the above control unit, a second parameter control step (S50) for controlling the parameters of the IPL based on the measured solvent concentration and the humidity on the outlet side. A drying method for an electrode sheet for a secondary battery, characterized by further including

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