KR20220157008A - Apparatus for drying electrode - Google Patents

Abstract

An electrode drying device according to the present invention includes: a hot air nozzle unit provided with at least one hot air nozzle for drying slurry by supplying hot air to the slurry applied on an electrode current collector; a broadband light source unit provided with at least one broadband light source for supplying light having multiple wavelengths to both corner portions of the slurry in a width direction; a hot air driving unit connected to the hot air nozzle and driving the hot air nozzle; a light source driving unit connected to the broadband light source and driving the broadband light source; and a control unit for controlling the operation of the hot air driving unit and the light source driving unit.

Description

Electrode drying device {Apparatus for drying electrode}

The present invention relates to an electrode drying device.

More specifically, the present invention relates to an electrode drying apparatus that uniformly dries a slurry applied on an electrode current collector using hot air and light having multiple wavelengths.

As technology development and demand for mobile devices increase, the demand for secondary batteries as an energy source is rapidly increasing. Batteries have been commercialized and are widely used.

On the other hand, in recent years, as interest in environmental issues has increased, electric vehicles (EVs) and hybrid electric vehicles that can replace vehicles using fossil fuels, including gasoline vehicles and diesel vehicles, which are one of the main causes of air pollution, A lot of research is being conducted on automobiles (HEVs). Although nickel metal hydride (Ni-MH) secondary batteries are mainly used as power sources for electric vehicles (EVs) and hybrid electric vehicles (HEVs), lithium secondary batteries with high energy density, high discharge voltage and output stability are used. Research is being actively conducted, and some of them are commercialized.

A lithium secondary battery (hereinafter referred to as a “secondary battery”) is an electrode assembly in which a porous separator is interposed between a positive electrode and a negative electrode on which an active material is applied on an electrode current collector, respectively, and a non-aqueous electrolyte containing a lithium salt is impregnated. It consists of a structure with

Lithium cobalt-based oxide, lithium manganese-based oxide, lithium nickel-based oxide, and lithium composite oxide are used as cathode active materials of secondary batteries, and carbon materials are mainly used as anode active materials, and silicon compounds and sulfur compounds are also used. is being considered

As a method for manufacturing an electrode of a secondary battery, a slurry is prepared by dispersing an active material, a conductive material, and a binder in a solvent, and then directly coated and dried on an electrode current collector to manufacture a secondary battery.

In general, a hot air drying method using hot air is employed as a method of drying a slurry applied on a conventional electrode current collector.

More specifically, in the conventional hot air drying method, the slurry is dried by supplying hot air to the slurry applied on the electrode current collector using a hot air nozzle to remove the solvent contained in the slurry.

1 is a view schematically showing the structure of a slurry dried by a conventional hot air drying method.

Referring to FIG. 1, when drying the slurry S applied to the electrode current collector G by a conventional hot air drying method, for example, the flow rate of hot air supplied by a hot air nozzle (not shown) is slow In this case, as the time for drying the slurry becomes longer, as shown in (a) of FIG. gradually become thinner. As a result, a dendrite structure in which lithium ions are deposited may be formed, and such a dendrite structure not only deteriorates the cycle performance of the secondary battery, but also has a problem of disconnection between the positive electrode and the negative electrode.

On the other hand, in order to prevent the above-described problem from occurring, when the flow rate of the hot air supplied by the hot air nozzle is increased, the flow rate of the hot air at both edge portions in the width direction of the slurry (S) is the hot air at the center of the slurry (S) As the flow rate is relatively higher than the flow rate, the widthwise edge portions of both sides of the slurry (S) are completed earlier than the central portion. In this case, as shown in (b) of FIG. 1, the active material present in the central portion of the slurry (S) is moved to both edge portions in the width direction of the slurry (S), and both edge portions in the width direction of the slurry (S) As this thickness becomes thicker than the central part, a protrusion (P) can be formed, and this protrusion (P) penetrates the separator by external pressure or vibration and connects the positive and negative electrodes to each other, thereby causing an internal short circuit of the electrode, resulting in a secondary battery. There is a problem that reduces safety.

Republic of Korea Patent Publication No. 10-2018-0086596 (published on August 1, 2018)

The present invention is to solve the problems of the prior art, and an object of the present invention is to dry the slurry applied on the electrode current collector using hot air and light having multiple wavelengths, so that the solvent contained in the slurry is uniformly It is to provide an electrode drying device capable of drying.

In order to achieve the above object, the electrode drying apparatus according to an embodiment of the present invention supplies hot air to the slurry applied on the electrode current collector to dry the slurry. A hot air nozzle equipped with at least one hot air nozzle wealth; a broadband light source unit provided with at least one broadband light source supplying light having multiple wavelengths to both corner portions of the slurry in the width direction; a hot air driver connected to the hot air nozzle and driving the hot air nozzle; a light source driver connected to the broadband light source and driving the broadband light source; and a control unit controlling operations of the hot air driving unit and the light source driving unit, wherein the at least one broadband light source dries both corner portions of the slurry in the width direction faster than drying by the hot air.

The following advantages are achieved by using the electrode drying apparatus according to an embodiment of the present invention.

1. As the slurry applied to the electrode current collector is dried using hot air and multi-wavelength light, the slurry can be uniformly dried as a whole.

2. As the slurry is quickly dried on both sides in the width direction by using a broadband light source irradiating light with wavelengths ranging from the ultraviolet region to the near infrared region, the thickness of the edge portions on both sides in the width direction of the slurry becomes thinner or Thickening can be prevented as much as possible.

3. Since slurry can be dried significantly faster than in the prior art, the drying process time (tact time) is greatly reduced, and as the drying space in the drying furnace can be minimized, the cost required for installing the drying furnace is also minimized.

4. Due to the above-mentioned advantages of 1 to 3, the total manufacturing time and cost of the final product (eg, lithium secondary battery) is greatly reduced.

1 is a view schematically showing the structure of a slurry dried by a conventional hot air drying method.
2 is a diagram schematically showing the structure of an electrode drying apparatus according to an embodiment of the present invention.
3 to 5 schematically show a configuration in which a plurality of broadband light sources are arranged in a horizontal direction and/or a vertical direction with respect to the transport direction of the electrode current collector on top of the electrode current collector according to an embodiment of the present invention. it is a drawing
6 is a graph showing a wavelength band of light using a broadband light source according to an embodiment of the present invention.
7 is a graph for explaining a comparison between a heat transfer state in a hot air drying method according to the prior art and a light irradiation state using a broadband light source according to an embodiment of the present invention.
8 is a diagram schematically illustrating a state in which a plurality of broadband light sources are connected in a serial or parallel manner to one light source driving unit according to an embodiment of the present invention.
9 is a view schematically showing the structure of an electrode drying apparatus to which a roll-to-roll method is applied according to an embodiment of the present invention.
10 is a state of both edge portions in the width direction of the slurry dried using a conventional hot air drying method, and both edge portions in the width direction of the slurry dried using a broadband light source of an electrode drying apparatus according to an embodiment of the present invention It is a diagram showing the comparison of images taken in the state of.

Hereinafter, a preferred embodiment according to the present invention will be described in detail with reference to the accompanying drawings. It should be noted that in the accompanying drawings, the same components are indicated by the same reference numerals as much as possible. In addition, detailed descriptions of well-known functions and configurations that may obscure the gist of the present invention will be omitted.

2 is a diagram schematically showing the structure of an electrode drying apparatus according to an embodiment of the present invention.

Referring to FIG. 2, the electrode drying apparatus 100 according to an embodiment of the present invention supplies hot air to the slurry S applied on the electrode current collector G to at least dry the slurry S. a hot air nozzle unit 110 having one hot air nozzle 111; a broadband light source unit 120 equipped with at least one broadband light source 121 supplying light having multiple wavelengths to both corner portions of the slurry S in the width direction; a hot air driving unit 130 connected to the hot air nozzle 111 and driving the hot air nozzle 111; a light source driver connected to the broadband light source 121 and driving the broadband light source 121; And a control unit 150 for controlling the operation of the hot air driving unit 130 and the light source driving unit; wherein the at least one broadband light source 121 heats both edge portions of the slurry S in the width direction to the hot air It is characterized in that it dries faster than drying by.

Hereinafter, specific configuration and operation of the electrode drying apparatus 100 according to an embodiment of the present invention will be described in detail.

Referring back to FIG. 2, the electrode drying apparatus 100 according to an embodiment of the present invention includes a hot air nozzle unit 110, a broadband light source unit 120, a hot air driver 130, a light source driver 140, and a control unit ( 150) may be included.

The hot air nozzle unit 110 according to an embodiment of the present invention supplies hot air to the slurry S applied on the electrode current collector G to dry the slurry S. At least one hot air nozzle 111 ) may be provided.

The hot air nozzle 111 is connected to the hot air driver 130 to be described later, and hot air can be supplied to the surface of the slurry S by the operation of the hot air driver 130. At this time, although not shown, the hot air driver 130 may be connected to a hot air generating device (not shown) having a built-in heater for generating hot air. Of course, in generating hot air, a heater (not shown) may be provided inside the hot air nozzle 111 to generate hot air inside the hot air nozzle 111 and supply it to the slurry S.

3 to 5, a plurality of hot air nozzles 111 according to an embodiment of the present invention may be used, and the plurality of hot air nozzles 111 may be disposed on the upper side of the electrode current collector G. can

3 to 5 show a plurality of hot air nozzles 111 according to an embodiment of the present invention in a direction horizontal and/or perpendicular to the transfer direction of the electrode current collector G from the top of the electrode current collector G. It is a diagram schematically showing the components arranged in the direction.

The plurality of hot air nozzles 111 according to an embodiment of the present invention are arranged in a direction perpendicular to the transfer direction of the electrode current collector G on the top of the electrode current collector G (see FIG. 3), or the electrode current collector G It may be arranged in a direction horizontal to the transport direction of the electrode current collector (G) at the top of the whole (G). (See FIG. 4) In addition, the plurality of hot air nozzles 111 are arranged in a vertical direction and some in a horizontal direction with respect to the transfer direction of the electrode current collector G at the top of the electrode current collector G. It can be. (See FIG. 5 ) In the embodiment of FIG. 5 , some of the plurality of hot air nozzles 111 are arranged in a direction perpendicular to the transport direction of the electrode current collector G, and sequentially the plurality of broadband light sources 121 Although the remaining part is illustratively shown as being arranged in a direction horizontal to the conveying direction of the electrode collector G, a portion of the plurality of hot air nozzles 111 is arranged in the conveying direction of the electrode collector G to those skilled in the art. It will be fully understood that the rest of the plurality of hot air nozzles 111 may be arranged in a direction perpendicular to the transport direction of the electrode current collector G.

The hot air driver 130 may be connected to a plurality of hot air nozzles 111 and may drive the plurality of hot air nozzles 111 .

It should be noted that the hot air driver 130 may be implemented in the form of a driving fan, but is not limited thereto.

The control unit 150 may control the operation of the hot air driving unit 130 . Specifically, the control unit 150 may control the hot air generating device to generate hot air and control the hot air driver 130 to supply the generated hot air to the slurry S through the hot air nozzle 111 .

When the hot air is supplied to the slurry (S) as described above, the slurry (S) may be dried while the solvent contained in the slurry (S) is vaporized by the supplied hot air.

On the other hand, when the slurry (S) is dried by the hot air supplied by the hot air nozzle 111, the thickness of both edge portions in the width direction of the slurry (S) is greater than the central portion according to the hot air flow rate supplied to the slurry (S) A problem of gradually becoming thinner or thicker may occur.

The electrode drying apparatus 100 according to an embodiment of the present invention allows the slurry S to be quickly dried by using the broadband light source 121 on both side edges in the width direction.

The broadband light source unit 120 irradiates light having multiple wavelengths in a broadband wavelength band toward both edge portions in the width direction of the slurry S applied on the electrode current collector G, so that both edges of the slurry S in the width direction It may include a broadband light source 121 that removes the solvent contained in the part and a housing 122 in which the broadband light source 121 is accommodated. In this case, the broadband light source unit 120 according to an embodiment of the present invention may include at least one or more broadband light sources 121 .

The broadband light source 121 may be disposed above the electrode current collector G, and may be provided at both corner portions in the width direction of the electrode current collector G, respectively.

On the other hand, referring to FIG. 3, depending on the volume and length of the electrode drying apparatus 100, the broadband light source 121 may use a short broadband light source 121 having a length of about 150 mm, for example, 350 A broadband light source 121 having a length of about 800 mm may be used.

More specifically, as shown in (a) of FIG. 3, the plurality of broadband light sources 121 having a short length are located on both sides of the front of the plurality of hot air nozzles 111 with the plurality of hot air nozzles 111 interposed therebetween. each can be placed. Of course, those skilled in the art will fully understand that a plurality of broadband light sources 121 having short lengths may be respectively disposed at both rear sides of the plurality of hot air nozzles 111 with the plurality of hot air nozzles 111 interposed therebetween.

On the other hand, as shown in (b) of FIG. 3, a plurality of broadband light sources 121 having a long length may be respectively disposed on both sides of the plurality of hot air nozzles 111 with the plurality of hot air nozzles 111 interposed therebetween. have.

A wavelength band of light irradiated from each of the plurality of broadband light sources 121 according to an embodiment of the present invention may include a wavelength band of ultraviolet rays to a wavelength band of near infrared rays.

More specifically, the wavelength band of the broadband light source 121 may be, for example, a wavelength band including a range of 300 nm to 1200 nm.

The broadband light source 121 according to an embodiment of the present invention may include at least one inert gas selected from Xe, Kr, Ar, Ne, and He. It should be noted that a xenon lamp containing gas may be used, but is not limited thereto.

6 is a graph showing a wavelength band of light using the broadband light source 121 according to an embodiment of the present invention.

Referring to FIG. 6, when the broadband light source 121 according to an embodiment of the present invention is used, light having multiple wavelengths in the wavelength range of 300-1200 nm including the ultraviolet wavelength range and the near infrared wavelength range is applied to the slurry (S) As it is irradiated onto both edge portions in the width direction of, the total energy irradiation amount is increased compared to drying by hot air, and the intensity of the total energy is also increased, so that the surface and interior of the slurry (S) at both edge portions in the width direction of the slurry (S) Simultaneous drying of is possible, so that both edge portions in the width direction of the slurry (S) can be quickly dried.

The above-described graph shown in FIG. 6 is a graph obtained when a voltage of 1,000V is applied to a xenon lamp containing Xe gas as the broadband light source 121 .

Referring to FIG. 7 , FIG. 7 is a graph for explaining a comparison between a heat transfer state in the hot air nozzle 111 and a light irradiation state using the broadband light source 121 according to an embodiment of the present invention.

More specifically, referring to FIG. 7 (a), the hot air supplied by the hot air nozzle 111 is supplied in a horizontal direction to both edge portions in the width direction of the slurry (S). Accordingly, since drying starts from the surface at both edge portions in the width direction of the slurry (S) in contact with the hot air, it is difficult for the solvent present in the slurry (S) to escape through the dried surface and can be removed immediately. There is no, while the heat supplied to the surface of the slurry (S) by the hot air is transferred to the inside of the slurry (S) by conduction, a considerable time is required for the solvent inside the slurry (S) to be heated and removed, ultimately resulting in the slurry ( The drying time of both sides of S) in the width direction becomes significantly longer.

However, referring to (b) of FIG. 7 , when using the broadband light source 121 according to an embodiment of the present invention, a wide range of wavelength bands from the broadband light source 121 (specifically, the As shown, light having multiple wavelengths including a wavelength range of 300-1200 nm) is not only irradiated to the surface of the slurry (S) at both edge portions in the width direction of the slurry (S), but also the irradiated light is transmitted to the inside Since it has sufficient energy to be absorbed, it is possible to simultaneously dry the surface and inside of the slurry (S) at both edge portions in the width direction of the slurry (S), so that both edge portions in the width direction of the slurry (S) are dried only with hot air It can dry faster than that.

That is, the width direction edge portions of the slurry (S) are dried faster than the central portion, so that while the central portion of the slurry (S) is dried by hot air, the width direction edge portions of the slurry (S) are completely dried and dried It can retain its shape.

Therefore, in the prior art, when drying by hot air, the thickness of the slurry (S) gradually becomes thinner due to the flowability of the slurry (S) at the edges of both sides in the width direction of the slurry (S) or the active material is moved to increase the thickness. It can be prevented as much as possible. .

Referring to FIG. 8 , the light source driver 140 according to an embodiment of the present invention is connected to the broadband light source 121 and can drive the broadband light source 121 .

More specifically, referring to (a) and (b) of FIG. 8, in the electrode drying apparatus 100 (see FIG. 2) according to an embodiment of the present invention, the plurality of the plurality of The broadband light source 121 is connected to one light source driving unit 140 in parallel (see FIG. 8(a)) or in series (see FIG. 8(b)), so that one light source driving unit 140 is connected in plurality. The broadband light source 121 of can be driven.

Of course, it is possible to connect and drive one broadband light source 121 to one light source driver 140, but in order to reduce the overall size of the electrode drying device 100, a plurality of broadband light sources are connected to one light source driver 140. It is preferable to drive the light sources 121 by connecting them in parallel or in series.

Referring back to FIG. 2 , the control unit 150 according to an embodiment of the present invention may control the operation of the light source driving unit 140. For example, the control unit 150 is a micro control unit (MCU) can be implemented as

The control unit 150 may control the amount of light emitted from the plurality of broadband light sources 121 by controlling the light source driving unit 140 using a pulse width modulation (PWM) method.

On the other hand, the control unit 150 sets the driving frequency for the plurality of broadband light sources 121 in the range of 1-20 Hz, the on-time control time in the range of 300-1000 μs, and the allowable current in the range of 100-1,200 A. range, and the discharge voltage can be controlled within the range of 500-2,000V.

Referring to FIG. 9, the electrode drying apparatus 100 (see FIG. 2) according to an embodiment of the present invention, for example, the electrode drying apparatus 100 according to an embodiment of the present invention (see FIG. 2) The hot air nozzle unit 110 and the broadband light source unit 120 are provided in the drying chamber 160, and the electrode current collector G to which the slurry S is applied is continuously introduced into the drying chamber 300 and dried. It can be implemented in a two-roll (R2R) manner.

At this time, the electrode drying apparatus 100 may include an unwinder 171 and a rewinder 172 for continuously supplying the electrode current collector G into the drying chamber 160 .

More specifically, the unwinder 171 may be implemented in the form of a roll, and may continuously unwind the electrode current collector G wound on the roll and supply it into the drying chamber 160 . The rewinder 172 may continuously wind and recover the dried electrode current collector G in the drying chamber 160 . That is, the electrode current collector G is supplied into the drying chamber 160 from the unwinder 170 and is continuously recovered from the rewinder 172 after the drying process in the drying chamber 160 is completed.

At this time, the drying chamber 160 provided with the broadband light source unit 120 of the electrode drying device 100 has an inlet 161 into which the electrode current collector G is inserted and an outlet port through which the dried electrode current collector G is discharged ( 162) may be provided.

A predetermined drying space 163 may be formed inside the drying chamber 160, and the drying space 163 is a substantially hexahedral space corresponding to the shape of the electrode current collector G to which the slurry S is applied. It should be noted that it may have a planar shape, but is not limited thereto.

That is, in the electrode drying apparatus 100 implemented in the roll-to-roll method shown in FIG. 9, the plurality of electrode current collectors G to which the slurry S is applied are the unwinder 171 and the rewinder 172 It can be continuously supplied by the operation of and pass through the inside of the electrode drying device 100. Accordingly, for each slurry S applied on the plurality of electrode current collectors G by the hot air nozzle unit 110 and the broadband light source 121 provided in the electrode drying apparatus 100 (see FIG. 2) It is possible to perform a continuous drying process, thereby greatly reducing the overall process time and mass production of good final products (eg, lithium secondary batteries).

Reference numeral N in FIG. 9 denotes a coating nozzle that applies the slurry S onto the current collector G.

10 shows the state of both edge portions in the width direction of the slurry S dried using a conventional hot air drying method, and the slurry dried using the broadband light source 121 of the electrode drying device according to an embodiment of the present invention It is a diagram showing the state of both edges in the width direction of (S) by comparing images taken.

That is, as shown in the photographed image of FIG. 10 (a), both edge portions in the width direction of the slurry (S) dried using the conventional hot air drying method are formed at an angle of about 14 degrees to the horizontal plane, so that the center portion On the other hand, as shown in the photographed image of FIG. 10 (b), the broadband light source 121 of the electrode drying apparatus according to an embodiment of the present invention is used. The corner portions of both sides of the dried slurry S in the width direction are formed at approximately 78 degrees to the horizontal plane, indicating that the length of the thinned portion is significantly reduced compared to the central portion.

As described above, the electrode drying apparatus according to an embodiment of the present invention dries the slurry applied to the electrode current collector using hot air and multi-wavelength light, so that the slurry can be uniformly dried as a whole.

In addition, as the slurry is quickly dried on both sides in the width direction by using a broadband light source irradiating light of a wavelength having a variety of wavelengths from the ultraviolet region to the near infrared region, the thickness of the edge portions on both sides in the width direction of the slurry becomes thinner or Thickening can be prevented as much as possible.

In addition, since the slurry can be dried significantly faster than in the prior art, the drying process time (tact time) is greatly reduced, and the cost required for installing the drying furnace is minimized as the drying space in the drying furnace can be minimized.

In addition, due to the advantages of 1 to 3 described above, the total manufacturing time and cost of the final product (eg, lithium secondary battery) is greatly reduced.

As described above, the present invention has been described with reference to the accompanying drawings and exemplary embodiments, but the protection scope of the present invention is not limited to these drawings and exemplary embodiments, and within the scope of the technical idea of the present invention, any Modifications and transformations of can be implemented.

100: electrode drying device 110: hot air nozzle unit
111: hot air nozzle 120: broadband light source
121: broadband light source 121: housing
130: hot air driving unit 140: light source driving unit
150: control unit 160: drying chamber
161: inlet 162: outlet
163: drying space 171: unwinder
172: rewinder
G: electrode current collector S: slurry

Claims (10)

In the electrode drying device,
a hot air nozzle unit provided with at least one hot air nozzle for drying the slurry by supplying hot air to the slurry applied on the electrode current collector;
a broadband light source unit provided with at least one broadband light source supplying light having multiple wavelengths to both corner portions of the slurry in the width direction;
a hot air driver connected to the hot air nozzle and driving the hot air nozzle;
a light source driver connected to the broadband light source and driving the broadband light source; and
a control unit controlling operations of the hot air driving unit and the light source driving unit;
Including,
The at least one broadband light source dries both corner portions of the slurry in the width direction faster than drying by the hot air. According to claim 1,
The electrode drying device having a wavelength band of the broadband light source in the range of 300 nm to 1200 nm. According to claim 1,
The broadband light source is an electrode drying device comprising at least one inert gas of Xe, Kr, Ar, Ne, and He. According to claim 3,
An electrode drying apparatus in which a xenon lamp containing Xe gas is used as the broadband light source. According to claim 1,
The hot air nozzle is implemented as a plurality of hot air nozzles provided on the upper part of the electrode current collector, and is arranged in either a horizontal direction or a vertical direction with respect to the transport direction of the electrode current collector, or in both directions. arranged electrode drying device. According to claim 5,
The broadband light source is provided on the upper part of the electrode current collector, and is provided at both edge portions in the width direction of the electrode current collector with the plurality of hot air nozzles interposed therebetween. According to claim 6,
The broadband light source is an electrode drying device connected to the light source driver in a parallel or serial manner. According to any one of claims 1 to 7,
The broadband light source unit further comprises a housing accommodating the broadband light source. According to any one of claims 1 to 7,
The control unit controls the irradiation amount of light emitted from the broadband light source by controlling the light source driving unit using a pulse width modulation (PWM) method. According to any one of claims 1 to 7,
a drying chamber having an inlet into which the electrode current collector is inserted and an outlet through which the electrode current collector is discharged, and a drying space in which the at least one hot air nozzle unit and the broadband light source unit are disposed; and
an electrode sheet supply unit including an unwinder for supplying the electrode current collectors and an electrode sheet rewinder for collecting the electrode current collectors; more inclusive
electrode dryer.

Images