KR102602478B1 - Drying apparatus for anode/cathode material of secondary battery by induction heating type - Google Patents

Abstract

The induction heating type secondary battery polar material drying device according to the present invention includes a drying chamber; a bobbin body provided at the center of the drying chamber in the longitudinal direction of the drying chamber and on which a roll to be dried, on which a negative electrode material or positive electrode material of a secondary battery is wound, is mounted; and an induction heating coil body provided in the drying chamber and spaced apart from the bobbin body by a preset distance in the radial direction to dry the roll to be dried by induction heating, and a container for accommodating the induction heating coil body. It may include an induction heating source unit including a casing.
The induction heating type secondary battery electrode material drying device according to the present invention, instead of indirect hot air drying, is used to dry the target roll itself due to the magnetic field generated between the induction heating coil body and the electrode around the target roll. As eddy currents are induced and heat is generated, heat loss can be reduced and drying time can be shortened. At the same time as induction heating, the inner surface of the roll to be dried is resistively heated through a resistance heating heater provided at the center of the electrode, increasing the drying yield. This is improved and drying can proceed regardless of the atmospheric pressure, so the drying tact time can be reduced.

Description

Secondary battery polar material drying device using induction heating {DRYING APPARATUS FOR ANODE/CATHODE MATERIAL OF SECONDARY BATTERY BY INDUCTION HEATING TYPE}

The present invention relates to an induction heating type secondary battery electrode material drying device, and more specifically, to an induction heating type secondary battery that can efficiently remove moisture or solvent contained in the negative electrode material or positive electrode active material of the secondary battery. It is about a drying device for extreme substances.

Secondary batteries are configured to repeat charging and discharging as ions in the electrolyte move between the anode and cathode insulated by a separator.

Secondary batteries include a cathode material, an anode material, an electrolyte, and a separator. Here, the positive electrode material or the negative electrode material may be prepared by applying an electrode current collector made of a metal material and an electrode active material layer on the electrode current collector.

Lithium composite metal compounds such as LiCoO2, LiMnO2, LiMn2O4 and LiFePO4 are used as positive electrode active materials for secondary batteries, and carbon including metal lithium, graphite and activated carbon are used as negative electrode active materials. Carbon based materials, etc. are used.

These positive and negative electrode materials essentially require a drying process to remove moisture or solvent contained in the negative electrode material or positive electrode active material after the electrode active material is applied on the electrode current collector.

In the existing drying process, the so-called hot air drying method has been generally used, in which a resistance heating heater is driven and hot air is applied to the anode and cathode materials through an airflow passing through it to conduct heat while drying. Here, in order for heat energy to be transferred, the vacuum degree of the drying furnace needs to be maintained at approximately 500 to 700 torr.

However, this hot air drying method has problems in that hot air is transmitted to the surface of the object to be dried and the object is dried as heat conduction progresses to the inside, resulting in large heat loss, high energy consumption, and long drying time.

In addition, if the object to be dried is thick, the drying yield decreases in the deep position of the object, and a medium through which the heat source of hot air must be transmitted is necessary, so a specific atmospheric pressure must be created before the drying process, thereby reducing the overall tact time of the drying process. There is an increasing problem.

The present invention was proposed to solve the above problems, and instead of indirect hot air drying, an eddy current is generated in the roll to be dried itself due to the magnetic field generated between the induction heating coil body and the electrode around the roll to be dried. As heat is generated and heated simultaneously inside the product affected by the magnetic field, it can be dried, reducing heat loss and reducing drying time compared to the existing hot air method that heats from the surface. In addition, the electrode is heated at the same time as induction heating. An induction heating type secondary battery electrode that improves drying yield by resistively heating the inner surface of the roll to be dried through a resistance heating heater provided in the center, and allows drying to proceed regardless of atmospheric pressure, thereby reducing drying tact time. A material drying device is provided.

In order to achieve the above object, an induction heating type secondary battery electrode material drying device according to the present invention includes a drying chamber; a bobbin body on which a roll to be dried is mounted, which is provided in the longitudinal direction of the drying chamber at the center of the drying chamber; and an induction heating coil body provided in the drying chamber and spaced apart from the bobbin body by a preset distance in the radial direction to dry the roll to be dried by induction heating, and a container for accommodating the induction heating coil body. It may include an induction heating source unit including a casing.

The outer surface of the accommodating casing has a longitudinal cross-sectional shape of 4 to 8 squares, the induction heating coil body is arranged to be built into the accommodating casing, and the induction heating source portion may be provided with a support die for supporting the accommodating casing. there is.

The bobbin body is provided with a through hole in the longitudinal direction at the center, and the through hole may be provided to accommodate an electrode body that interacts with the induction heating coil body.

The bobbin body may be provided with a resistance heating heater unit of a resistance heating type.

The resistance heating heater unit may be a plurality of resistance coils disposed to be recessed on the outer surface of the bobbin body.

The roll to be dried may be laminated with positive electrode material or negative electrode material for a secondary battery.

The induction heating type secondary battery electrode material drying device according to the present invention, instead of hot air drying, generates eddy currents in the roll to be dried itself due to the magnetic field generated between the induction heating coil body and electrodes with the roll to be dried in between. It can be dried while induction and heat is generated, which reduces heat loss and can reduce heating time by simultaneously heating a large area where a magnetic field is formed. Simultaneously with induction heating, the inside of the roll to be dried is provided through a resistance heating heater provided at the center of the electrode. The drying yield is improved by resistively heating the cotton, and drying can proceed regardless of the atmospheric pressure, thereby reducing the drying tact time.

Figure 1 is a conceptual diagram of an induction heating method according to an embodiment of the present invention.
Figure 2 is a side view and a front view of a roll to be dried, which is an object to be dried in an induction heating type secondary battery polar material drying apparatus according to an embodiment of the present invention.
Figure 3 is a perspective view of an induction heating secondary battery polar material drying device according to an embodiment of the present invention.
Figure 4 is a partial projection view of a state in which a roll to be dried is loaded into a drying chamber in an induction heating type secondary battery electrode material drying apparatus according to an embodiment of the present invention.
Figure 5 is a cut-away perspective view of the drying chamber of the induction heating type secondary battery polar material drying apparatus according to an embodiment of the present invention.
Figure 6 is a side longitudinal cross-sectional view of the drying chamber of the induction heating type secondary battery electrode material drying device according to an embodiment of the present invention.
Figure 7 is a front longitudinal cross-sectional view of the drying chamber of the induction heating type secondary battery electrode material drying apparatus according to an embodiment of the present invention.
Figure 8 is a graph of a drying process performed in a conventional resistance heating type drying furnace.
Figure 9 is a graph of the drying process performed in the induction heating type secondary battery electrode material drying apparatus according to this embodiment.
Figure 10 is a diagram schematically showing an object to be dried and an induction heating coil body in an induction heating type secondary battery electrode material drying apparatus according to another embodiment of the present invention.
Figure 11 is a graph of a drying process performed in an induction heating type secondary battery electrode material drying apparatus according to another embodiment of the present invention.

Hereinafter, an embodiment of an induction heating type secondary battery electrode material drying device according to the present invention will be described in detail with reference to the attached drawings.

Figure 1 is a conceptual diagram of an induction heating method according to an embodiment of the present invention, and Figure 2 is a side view and a front view of a roll to be dried, which is an object to be dried in an induction heating type secondary battery electrode material drying device according to an embodiment of the present invention. 3 is a perspective view of an induction heating type secondary battery pole material drying device according to an embodiment of the present invention, and Figure 4 is a drying chamber in an induction heating type secondary battery pole material drying device according to an embodiment of the present invention. It is a partial projection view of the state in which the roll to be dried is loaded, Figure 5 is a cut-away perspective view of the drying chamber of the induction heating type secondary battery electrode material drying apparatus according to an embodiment of the present invention, and Figure 6 is an embodiment of the present invention. It is a side longitudinal cross-sectional view of the drying chamber of the induction heating type secondary battery pole material drying device according to the present invention, and Figure 7 is a front longitudinal cross-sectional view of the drying chamber of the induction heating type secondary battery pole material drying device according to an embodiment of the present invention.

An induction heating type secondary battery polar material drying apparatus according to an embodiment of the present invention includes a drying chamber 100; A bobbin body 200 provided at the center of the drying chamber 100 in the longitudinal direction of the drying chamber 100 and on which a roll 10 to be dried, on which a negative or positive electrode material of a secondary battery is wound, is mounted; And an induction heating coil body 310 that is provided in the drying chamber 100 and is spaced apart from the bobbin body 200 by a preset distance in the radial direction to dry the target roll 10 by induction heating. ) and an induction heating source unit 300 including a receiving casing 320 for accommodating the induction heating coil body 310.

First, the induction heating method is explained.

Induction heating uses the principle that eddy currents are induced in metal materials that are energized through a magnetic field generated by a current applied to a coil, and these eddy currents generate heat in metal materials due to energy loss caused by hysteresis.

As shown in FIG. 1, when a high-frequency current is applied, magnetic force is generated on the resistance coil 231, the magnetic force line passes through the electrode body 220, and a voltage is induced, and the induced current is generated by the induced voltage. is generated and the electrode body 220 is heated. When an object to be dried is placed on the electrode body 220, the object to be dried can be dried using an induction heating method.

Meanwhile, an electrode material of a negative electrode material or a positive electrode material may be wound around the roll 10 to be dried. Here, the electrode material may be composed of an active material, a conductive material, and a binder. The active material is a material that accepts and emits ions, and various materials are being studied depending on the anode or cathode. The conductive material is a material that increases electrical conductivity and may be, for example, carbon black. The binder is a material that fixes the active material and the conductive material during charging and discharging, and may be a polymer.

And the electrode current collector 2 may be a metal foil with a thickness of 3 to 100 ㎛, and the electrode material is applied and laminated on the electrode current collector, and then roll-to-roll (as shown in FIG. 2). It is loaded in a roll-to-roll manner and transported and processed.

As shown in FIG. 2, a negative electrode material or positive electrode material for a secondary battery may be prepared by being coupled to a central bobbin. The specifications of the roll 10 to be dried may vary depending on the manufacturer's requirements, and in this embodiment, the diameter may be 500 mm and the width may be 340 mm.

The drying chamber 100 may be provided in a size that can sufficiently accommodate the roll 10 to be dried. Referring mainly to FIG. 3, the drying chamber 100 may be connected to a vacuum exhaust line 131 and a vacuum pump 130 to enable vacuum pressure or a specific pressure that meets design standards.

The drying chamber 100 may be one of the drying chambers 100, and a front cover may be provided on the front side to enable loading and unloading of the roll 10 to be dried. At least one hatch may be provided on the outer surface of the drying chamber 100.

The bobbin body 200 may be provided in the center of the drying chamber 100 in the longitudinal direction of the drying chamber 100. That is, referring mainly to FIG. 4, the bobbin body 200 is a cantilever type in which one end is fixedly supported on the rear wall (left part of FIG. 4) of the drying chamber 100, and the other end is provided to protrude horizontally from the center toward the front cover. It can be prepared by: In addition, the roll to be dried (10) may be loaded into the other floating end and may be taken out.

Referring to FIGS. 5 and 6, the bobbin body 200 is provided with a through hole 210 in the longitudinal direction at the center, and the through hole 210 is provided with an electrode that interacts with the induction heating coil body 310. Sieve 220 may be arranged to accommodate. This electrode body 220 may interact with the resistance coil 231 of the induction heating source unit 300, which will be described later, to enable induction heating.

Meanwhile, according to our own experiments, in the induction heating method, the area where the magnetic field (which has a significant effect on drying) is formed is formed to a depth of about 100 mm from the surface of the roll 10 to be dried. Accordingly, a resistance heating method to complement the induction heating method may be additionally added.

Accordingly, in this embodiment, the bobbin body 200 may be provided with a resistance heating heater unit 230 of a resistance heating type. The resistance heating heater unit 230 may be a plurality of resistance coils 231 accommodated in an inner depression 232 formed to be recessed in the outer surface of the bobbin body 200. For example, the resistance coil heater unit may be an inconal heater. can be applied. Here, due to the inner depression 232, it can be easy to load and unload the roll 10 to be dried.

Accordingly, when the thickness of the roll 10 to be dried is greater than the design predicted thickness (eg, 100 mm), the resistance heating method can be used as an auxiliary method to improve the drying yield.

The induction heating source unit 300 is provided in the drying chamber 100 and is arranged to be spaced apart from the bobbin body 200 by a preset distance in the radial direction to heat the roll to be dried 10 by induction heating. It may include a drying induction heating coil body 310 and a receiving casing 320 that accommodates the induction heating coil body 310.

The induction heating coil body 310 may be arranged to be built into the receiving casing 320. And since the inside of the receiving casing 320 adjacent to the target roll 10 is provided in an open form, the induction heating coil body 310 is disposed adjacent to the target roll 10 to increase induction heating efficiency. You can.

The receiving casing 320 is arranged to surround the outside of the induction heating coil body 310 and serves to protect the induction heating coil body 310. Referring to FIG. 7, the outer surface of the receiving casing 320 may have an octagonal vertical cross-sectional shape. The interior of the receiving casing 320 may be provided in an open form.

The induction heating source unit 300 may be provided with a support die 330 that supports the receiving casing 320.

Through the induction heating type secondary battery electrode material drying device of this configuration, instead of indirect hot air drying, the magnetic field generated between the induction heating coil body 310 and the electrode around the target roll 10 to be dried is used. An eddy current is induced in the roll to be dried (10) itself, and it can be dried while generating heat, thereby reducing heat loss and shortening drying time. At the same time as induction heating, the roll (10) is heated through a resistance heating heater unit (230) provided at the center of the electrode. The drying yield is improved by resistively heating the inner surface of the drying target roll 10, and drying can proceed regardless of the atmospheric pressure, thereby reducing the drying tact time.

Figure 8 is a graph of a drying process performed in a conventional resistance heating type drying furnace, and Figure 9 is a graph of a drying process performed in an induction heating type secondary battery electrode material drying device according to this embodiment.

Hereinafter, a drying test was conducted using the induction heating type secondary battery polar material drying device according to this example.

Induction heating drying test

(1) Object to be dried

An experiment was conducted using the drying object roll 10 of FIG. 2 as the object to be dried, the specification of the electrode material was Ø500 x 340 mm, and the NCM anode material was prepared in a roll shape.

(2) Control group setting

An existing resistance heating type drying furnace was used, and an indirect hot air drying method using an inconal heater was used. During the drying process, the atmospheric pressure was maintained at approximately 950 KPa (710 torr).

(3) Experimental method

The target temperature is set at 120℃, and the temperature by time and temperature by point are at 3 points: 10 mm from the surface of the roll 10 to be dried (1 point), the center point (2 points), and 10 mm from the bobbin (3 points). Deviation was confirmed.

(3) Test results

In the case of the existing resistance heating type drying furnace, as shown in Figure 8, after 2 hours, the temperature was measured at 79.5 ℃ at 1 point, 66.5 ℃ at point 2, 70 ℃ at point 3, and the temperature deviation was 13 ℃.

And after 4 hours, 96°C was measured at 1 point, 90°C at point 2, and 92°C at point 3, and the temperature deviation was measured at 6°C. Until 4 hours have elapsed, the drying temperature is far short of the target temperature (maximum 96 ℃, 80% of the target temperature), and the temperature deviation for each position of the roll 10 to be dried is 6 ℃, which is the temperature deviation for each point. exists. In addition, due to the time loss and cost of creating atmospheric pressure, the power consumption was confirmed to be 68 KW because it is an indirect hot air drying method.

On the other hand, as shown in FIG. 9 according to this embodiment, during the drying process using the induction heating type secondary battery electrode material drying device, after 2 hours, point A is 114 ℃, point B is 112 ℃, and point C is 109 ℃. ℃ and the temperature deviation was measured at 5 ℃. After 4 hours, point A was 116 ℃, point B was 118 ℃, and point C was 117 ℃, and the temperature deviation was measured at 2 ℃.

All three points are approaching the target temperature in 4 hours, and the temperature deviation at each point is only 2℃, which is 3 times better than the existing resistance heating method.

In addition, the induction heating method is a method in which the roll to be dried (10) itself is heated, which does not require a heat transfer medium, so there is no time loss or cost of creating atmospheric pressure, and the power consumption was confirmed to be 35 KW, which is half that of the existing resistance heating method. The above power reduction was confirmed.

Looking at these test results, instead of indirect hot air drying, there is an eddy current in the roll to be dried (10) itself due to the magnetic field generated between the induction heating coil body (310) and the electrode around the roll to be dried (10). can be dried while being induced and generating heat, thereby reducing heat loss and reducing drying time. At the same time as induction heating, the inner surface of the roll to be dried (10) is heated through the resistance heating heater unit 230 provided at the center of the electrode. Drying yield is improved by resistance heating, and drying can proceed regardless of atmospheric pressure, thereby reducing drying tact time.

Figure 10 is a diagram schematically showing an object to be dried and an induction heating coil body in an induction heating type secondary battery electrode material drying apparatus according to another embodiment of the present invention, and Figure 11 is a diagram schematically showing an induction heating coil according to another embodiment of the present invention. This is a graph of the drying process performed in a heating type secondary battery electrode material drying device.

Hereinafter, only the different configurations of the induction heating type secondary battery electrode material drying device according to another embodiment of the present invention will be described with reference to FIGS. 10 and 11.

In the drying device according to the present embodiment, unlike the roll to be dried in the first embodiment, the object to be dried is laminated in a state in which the positive or negative active material is cut to a certain length by unwinding the roll as shown in Figure 10 (a). It can be provided as a layer type (10a) or as a so-called cell type (10b) in which the positive electrode material, negative electrode material, and separator are stacked, equipped with an external casing, and stored in a magazine, as shown in (b) of FIG. 10. .

Induction heating coil bodies (310a, 310b) are provided to correspond to the outer circumferential shape of the layer type (10a) or cell type (10b), and in the layer type (10b), a tray (11) for storing and mounting the layers is provided. And, in the cell type, a magazine (not shown) that stores battery cells or battery cans may be added.

Figure 11 shows the results of a layer-type object to be dried being stacked on a tray and a drying test performed thereon.

According to this, the remaining test results, except for the initial tests 0 and 1, which recorded the lowest score, showed that the drying process was performed while maintaining the drying temperature of approximately 90°C for 30 minutes of the drying test.

Compared to the first example, the target temperature was reduced by more than 10%, but the drying time to reach the target temperature was significantly reduced (more than 4 times).

Above, the present invention has been described in detail using preferred embodiments, but the scope of the present invention is not limited to the specific embodiments and should be interpreted in accordance with the appended claims. Additionally, those skilled in the art should understand that many modifications and variations are possible without departing from the scope of the present invention.

10: Roll to be dried
100: drying chamber 110: front cover
120: Vacuum exhaust line 200: Bobbin body
210: through hole 220: electrode body
230: resistance heating heater unit 231: resistance coil
300: Induction heating source part 310: Induction heating coil body
320: Accommodating casing 330: Support die

Claims (7)

drying chamber;
a bobbin body provided at the center of the drying chamber in the longitudinal direction of the drying chamber and on which a roll to be dried, on which a negative electrode material or positive electrode material of a secondary battery is wound, is mounted; and
A cylindrical device is provided inside the drying chamber, is spaced apart from the bobbin body by a preset distance in the radial direction, and dries the roll by inducing an eddy current to the roll mounted on the bobbin body. Induction heating coil body; and an induction heating source unit including a housing casing for accommodating the induction heating coil body,
In the through hole formed in the longitudinal direction at the center of the bobbin body,
An electrode body that interacts with the induction heating coil body is accommodated,
In the bobbin body,
A resistance heating heater unit is provided to heat the inner surface of the roll to be dried,
The resistance heating heater unit,
An induction heating type secondary battery electrode material drying device, comprising a plurality of resistance coils disposed in a depression formed on the outer surface of the bobbin body so as not to interfere with the loading and unloading of the roll to be dried. delete delete delete delete According to paragraph 1,
An induction heating type secondary battery electrode material drying device, characterized in that the roll to be dried is laminated with a positive electrode material or a negative electrode material for a secondary battery. delete