Electrode manufacturing equipment and electrode manufacturing method

Abstract

To reduce cost in a drying step when manufacturing an electrode.SOLUTION: An electrode manufacturing facility 10 comprises a dryer 11, first piping 12, a solvent collection device 13, an outside air introduction pipe 14, a heat exchanger 15, and second piping 16. The first piping 12 is for sending exhausted air, which is exhausted from the dryer 11, to the solvent collection device 13. The solvent collection device 13 is for collecting an organic solvent, which is contained in the exhausted air exhausted from the dryer 11, while dissolving the solvent in water. The heat exchanger 15 is configured to perform heat exchange between the exhausted air exhausted from the dryer 11 and the outside air introduction pipe 14. The second piping is connected to piping 13c, in which the exhausted air after passing the solvent collection device 13 is exhausted, and to the outside air introduction pipe 14 at an upstream side of the heat exchanger 15 and sends at least a portion of the exhausted air after passing the solvent collection device 13 to the outside air introduction pipe 14.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an electrode manufacturing facility and an electrode manufacturing method. [Background technology]

[0002] Japanese Patent Application Publication No. 2012-097917 discloses a drying apparatus for drying a substrate having a slurry coating while being transported. The drying apparatus disclosed in Japanese Patent Application Publication No. 2012-097917 includes a drying furnace for drying the coating on the substrate and an exhaust port for discharging gas from the drying furnace to the outside. The drying furnace has multiple drying zones along the transport direction of the substrate, each with a different drying atmosphere. The exhaust port of the drying furnace is located downstream of the most upstream drying zone among the multiple drying zones. With this drying apparatus, in the most upstream drying zone (i.e., the initial stage of drying), the solvent evaporated from the slurry coating is not exhausted, resulting in a high concentration of solvent gas in the drying furnace. When the solvent gas concentration in the drying furnace increases, it approaches saturated vapor pressure, inhibiting solvent evaporation. The publication states that this suppresses rapid drying of the slurry coating in the initial stage of drying, thereby preventing migration caused by rapid drying of the slurry coating in the initial stage of drying.

[0003] JP 2008-114203 A discloses a method for recovering organic solvents. When an organic solvent is used, the exhaust gas from the drying process contains the organic solvent, making it necessary to recover the organic solvent. Methods for recovering organic solvents include dry and wet methods. In dry treatment, for example, the exhaust gas from the drying process is cooled using cooling water or the like in an indirect heat exchanger, and the solvent components in the exhaust gas are condensed and recovered. In wet treatment, water is used as an absorbent to absorb the solvent components in the exhaust gas by introducing the exhaust gas into an absorption tower where water is sprayed. The publication states that in wet treatment, the lower the temperature, the more efficiently the solvent components are absorbed. For this reason, it is recommended that the exhaust gas introduced into the absorption tower be cooled in advance and brought into gas-liquid contact with a large amount of water. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-097917 [Patent Document 2] JP 2008-114203 A Summary of the Invention [Problem to be solved by the invention]

[0005] Meanwhile, while demand for lithium-ion secondary batteries is expected to increase with the shift to electric vehicles, a huge increase in costs is expected in the mass production of lithium-ion secondary batteries. In particular, it is desirable to reduce production costs by reducing the energy required in the drying process when manufacturing electrodes. The inventors believe that, as a method for recovering organic solvents from exhaust gas after drying, a wet method in which the organic solvent is absorbed into water is advantageous over a dry method in which the exhaust gas needs to be cooled to a level where the organic solvent condenses, and they would like to reduce production costs, including by recovering the organic solvent using a wet method. [Means for solving the problem]

[0006] The electrode manufacturing equipment disclosed herein includes a dryer, a solvent recovery device, a first pipe, an outside air introduction pipe, a heat exchanger, and a second pipe. The dryer includes a drying furnace, a heater, and a conveying device. The heater heats air supplied through an outside air inlet pipe and supplies the heated air into the drying furnace. The conveying device conveys a sheet-like current collector coated with a mixture slurry in which electrode active material particles are dispersed in an organic solvent along a predetermined conveying path within the drying furnace. The solvent recovery device is a device that recovers organic solvents contained in exhaust gas discharged from a dryer by dissolving them in water. The first pipe is a pipe that sends the exhaust gas discharged from the dryer to the solvent recovery device. The outside air introduction pipe is a pipe that introduces outside air and sends it to the dryer. The heat exchanger is a device configured to perform heat exchange between the first pipe and the outside air introduction pipe. The second pipe is a pipe that is connected to a pipe that discharges exhaust gas after passing through the solvent recovery device and to the outside air introduction pipe on the upstream side of the heat exchanger, and is a pipe that sends at least a portion of the exhaust gas after passing through the solvent recovery device to the outside air introduction pipe.

[0007] In this electrode manufacturing facility, the exhaust gas supplied from the second pipe after passing through the solvent recovery device is mixed into the outside air inlet pipe and then heat-exchanged with the exhaust gas from the dryer in the heat exchanger. This allows the temperature of the outside air introduced into the dryer to be increased in advance, thereby reducing the energy required for the dryer heater.

[0008] In this case, the outside air inlet pipe that sends outside air to the dryer may further include a heating device downstream of the heat exchanger. Alternatively, in another embodiment of the electrode manufacturing equipment, the second pipe may not be provided, and the outside air inlet pipe that sends outside air to the dryer may be provided with a heating device downstream of the heat exchanger.

[0009] The electrode manufacturing method disclosed herein includes a drying step of drying a sheet-shaped current collector coated with a mixture slurry in which electrode active material particles are dispersed in an organic solvent, and a solvent recovery step of spraying water onto the exhaust gas discharged in the drying step to dissolve the organic solvent contained in the exhaust gas in the water. In the drying step, a portion of the exhaust gas after being sprayed with water in the solvent recovery step is mixed with outside air and heat-exchanged with the exhaust gas discharged in the drying step, before being introduced into a dryer. In this case, in the drying step, the gas obtained by mixing a portion of the exhaust gas after being sprayed with water in the solvent recovery step with outside air may be heat-exchanged with the exhaust gas discharged in the drying step, further heated, and then introduced into the dryer.

[0010] Another embodiment of the electrode manufacturing method includes a drying step of drying a sheet-shaped current collector coated with a mixture slurry in which electrode active material particles are dispersed in an organic solvent, and a solvent recovery step of spraying water onto exhaust gas discharged from the dryer to dissolve the organic solvent contained in the exhaust gas in the water. In the drying step, outside air is subjected to heat exchange with the exhaust gas discharged in the drying step, and is then heated before being introduced into the dryer.

[0011] According to these electrode manufacturing methods, the temperature of the outside air introduced into the dryer can be increased in advance, and the energy required by the heater of the dryer can be kept low. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram showing the configuration of an electrode manufacturing facility 10. As shown in FIG. [Figure 2] FIG. 2 is a schematic diagram of the solvent recovery device 13. DETAILED DESCRIPTION OF THE INVENTION

[0013] The disclosure herein is explained below. Unless otherwise specified, the disclosure herein is not intended to limit the invention described in the claims of this application. Each drawing is a schematic representation and does not necessarily reflect the actual product. Furthermore, components and parts that perform the same function are appropriately designated by the same reference numerals, and redundant explanations will be omitted.

[0014] FIG. 1 is a configuration diagram showing the configuration of an electrode manufacturing facility 10. The electrode manufacturing facility 10 is used as a manufacturing apparatus for manufacturing electrode sheets used in electricity storage devices such as lithium-ion secondary batteries and electric double layer capacitors. The electrodes manufactured by the electrode manufacturing facility 10 are formed by forming an active material layer containing electrode active material particles on a sheet-like substrate that serves as a current collector. The method for manufacturing an electrode sheet includes a step of preparing a mixture slurry containing electrode active material particles for a battery electrode, a step of applying the mixture slurry to the substrate (application step), and a step of drying the applied mixture slurry (drying step).

[0015] A mixture slurry containing an active material for a battery electrode contains, for example, electrode active material particles, a binder, and the like in a solvent. The mixture slurry is also called a mixture paste. In the process of applying the mixture slurry to a substrate, the prepared mixture slurry is applied to a sheet-like substrate. Metal foils such as aluminum foil and copper foil can be used as the substrate for the electrode sheet. Here, the substrate for the electrode sheet is prepared, for example, in the form of a strip-like sheet. In the process of applying the mixture slurry to the substrate, the mixture slurry is supplied through a die or the like onto the electrode sheet transported by roll-to-roll. In the process of drying the applied mixture slurry, an active material layer containing electrode active material particles is formed on the electrode sheet by drying the applied mixture slurry. In the drying process, the electrode sheet is passed through a drying furnace, and the mixture slurry applied to the electrode sheet is dried. The active material layer that has undergone the drying process is adjusted to a predetermined thickness and density through a pressing process or the like.

[0016] The mainstream of positive electrode slurries for lithium ion secondary batteries uses organic solvents. Positive electrode slurries can use, for example, polyvinylidene fluoride (hereinafter, PVdF) as a binder to bind materials, and an organic solvent such as N-methyl-2-pyrrolidone (hereinafter, NMP) as a solvent. On the other hand, the mainstream of negative electrode slurries for lithium ion secondary batteries uses styrene-butadiene rubber (hereinafter, SBR), an aqueous dispersion type binder, and water as a solvent. Note that the materials used for the positive electrode slurries and negative electrode slurries are not limited to the materials exemplified here, unless otherwise specified.

[0017] The mixture slurry applied in the application process contains a required amount of solvent. In the process of drying the applied mixture slurry, the solvent needs to be evaporated. Therefore, in the mass production of lithium ion secondary batteries, a large amount of heat is required in the drying process in the manufacture of electrode sheets. Furthermore, when an organic solvent is used, the organic solvent is contained in the exhaust gas from the drying process. Therefore, the organic solvent needs to be recovered.

[0018] As shown in FIG. 1, the electrode manufacturing equipment 10 includes a dryer 11, a first pipe 12, a solvent recovery device 13, an outside air introduction pipe 14, a heat exchanger 15, a second pipe 16, a heating device 20, and a control device 40.

[0019] <Dryer 11> The dryer 11 is a device for drying a sheet-like current collector coated with a mixture slurry in which electrode active material particles are dispersed in an organic solvent. In the embodiment shown in Fig. 1, the dryer 11 includes a drying furnace 11a, a heater 11b, and a conveying device 11c.

[0020] Here, the drying furnace 11a may be configured with a furnace body surrounded by a heat insulating material. A dry atmosphere is formed in the closed space inside the drying furnace 11a. The drying furnace 11a is provided with an inlet 11a1 through which the current collector coated with the composite slurry is introduced and an outlet 11a2. A predetermined transport path is set in the drying furnace 11a along which the current collector coated with the composite slurry is transported. A dry atmosphere is formed inside the drying furnace 11a at a temperature at which the solvent contained in the composite slurry can evaporate, for example, 100°C or higher.

[0021] The heater 11b is, for example, a device that heats air supplied through the outside air introduction pipe 14 and supplies the air into the drying furnace 11a. The heater 11b may be, for example, an electric heater. Note that the heater 11b is not limited to an electric heater and may be a gas heater or the like. When NMP is used as the solvent, the heater 11b heats the air supplied through the outside air introduction pipe 14 to a predetermined temperature (for example, 115°C) and supplies the air to the dryer 11.

[0022] The conveying device 11c may be a device that conveys a sheet-like current collector coated with the mixture slurry. The current collector coated with the mixture slurry is, for example, a strip-shaped sheet, and is conveyed along a predetermined conveying path within the drying furnace 11a. The mixture slurry may be applied to the current collector before it enters the drying furnace 11a. In this embodiment, an applicator 11d that applies the mixture slurry to the current collector is provided upstream of the entrance 11a1 of the drying furnace 11a on the conveying path of the current collector. Here, the mixture slurry applied to the current collector may be a slurry in which electrode active material particles are dispersed in an organic solvent (e.g., NMP).

[0023] <First piping 12> The first pipe 12 is a pipe that sends exhaust gas discharged from the dryer 11 to the solvent recovery device 13. The exhaust gas discharged from the dryer 11 contains a solvent component. An organic solvent, such as NMP, used as the solvent component has a higher boiling point than water. Therefore, the exhaust gas discharged from the dryer 11 has a temperature of, for example, approximately 100°C. As shown in FIG. 1, the first pipe 12 is arranged so as to run from the drying furnace 11a through a heat exchanger 15 to the solvent recovery device 13. In the embodiment shown in FIG. 1, a blower fan 12a is provided in the first pipe 12. The exhaust gas discharged from the dryer 11 is forcibly sent to the solvent recovery device 13 by the blower fan 12a. The blower fan 12a is preferably provided in the first pipe 12 before the solvent recovery device 13. The blower fan 12a is controlled in conjunction with a blower fan 14a provided in an outside air introduction pipe 14 (described later) to optimize the drying conditions in the dryer 11. The flow rate of the exhaust gas sent from the dryer 11 to the solvent recovery device 13 can be controlled by controlling the blower fan 12a. To ensure a stable flow rate, a blower fan may be installed midway along the first pipe 12 depending on the length of the pipe. The air volume of the blower fan installed in the equipment may be controlled, for example, to maintain the conditions inside the drying oven.

[0024] <Solvent recovery device 13> The solvent recovery device 13 is a wet recovery device. In the embodiment shown in FIG. 1, water is supplied to the solvent recovery device 13 through a water supply pipe 13a, and the organic solvent contained in the exhaust gas discharged from the dryer 11 is dissolved in the water and recovered. Organic solvents such as NMP are easily soluble in water. Therefore, by spraying water on the exhaust gas discharged from the dryer 11, the organic solvent contained in the exhaust gas is absorbed into the water and efficiently recovered.

[0025] 2 is a schematic diagram of the solvent recovery apparatus 13. The solvent recovery apparatus 13 includes a plurality of recovery tanks 61a to 61d that are separated from one another. A pipe 62, through which the exhaust gas discharged from the dryer 11 flows, passes through the upper portions of the recovery tanks 61a to 61d. The recovery tanks 61a to 61d are lined up in order from the inlet side to the outlet side of the pipe 62. Fillers 62a to 62d for separating the organic solvent from the exhaust gas are enclosed in the pipe 62. The filler may be, for example, a mesh material known as a demister.

[0026] The water supplied to the solvent recovery device 13 is supplied to the recovery tanks 61a to 61d, respectively. The water supplied to the solvent recovery device 13 may be, for example, water adjusted to a required water quality, such as pure water. The water is supplied so that the water level accumulated in the recovery tanks 61a to 61d reaches a predetermined level. The water may be sprayed onto the fillers 62a to 62d. Alternatively, the water accumulated in the recovery tanks 61a to 61d may be pumped up by pumps 63a to 63d and sprayed from the top of the recovery tanks 61a to 61d. The water sprayed from the top of the recovery tanks 61a to 61d is contained in the fillers 62a to 62d. The organic solvent contained in the exhaust gas discharged from the dryer 11 is absorbed by the water as it passes through the fillers 62a to 62d.

[0027] The water that has absorbed the organic solvent accumulates in the collection tanks 61a to 61d. The water that has accumulated in the collection tanks 61a to 61d is sent sequentially from the outlet-side collection tank 61d to the inlet-side collection tank 61a. Therefore, the concentration of the organic solvent increases toward the inlet-side collection tank 61a. For example, the concentration of the organic solvent in the water that has accumulated in the collection tank 61a in each of the collection tanks 61a to 61d is measured, and when the concentration of the organic solvent reaches a predetermined concentration based on the measurement value, the valve opens and the water is sent to the next collection tank. The concentration of the organic solvent in the inlet-side collection tank 61a increases, and the water is sequentially drained from the solvent recovery device 13.

[0028] As shown in FIG. 1, the water that has absorbed the organic solvent can be separated into the organic solvent and the water by distillation in reprocessing equipment 13b or the like. The water separated from the organic solvent may be reused in solvent recovery equipment 13. The separated organic solvent can also be re-purified so that it can be reused. In solvent recovery equipment 13, the exhaust gas after the organic solvent has been absorbed into water is discharged through pipe 13c. As described below, second pipe 16 is connected to pipe 13c, through which the exhaust gas discharged from solvent recovery equipment 13 flows. In the example shown in FIG. 1, reprocessing equipment 13b is installed on-site. Reprocessing equipment 13b may also be installed off-site, for example. In this case, a storage tank for storing the water that has absorbed the organic solvent may be installed and the water may be transported by a tanker truck or the like to off-site reprocessing equipment 13b, where the organic solvent may be reprocessed.

[0029] <Outside air intake pipe 14> The outside air introduction pipe 14 is a pipe that introduces outside air and sends it to the dryer 11. The outside air introduction pipe 14 is piped to reach the dryer 11 via a heat exchanger 15. In the embodiment shown in FIG. 1 , a portion of the exhaust air discharged from the solvent recovery device 13 is configured to be supplied to the outside air introduction pipe 14 via a second pipe 16. A blower fan 14a is provided in the outside air introduction pipe 14 upstream of the heat exchanger 15. The blower fan 14a forcibly sends outside air from the outside air introduction pipe 14 to the heat exchanger 15. The flow rate of the outside air sent from the outside air introduction pipe 14 to the heat exchanger 15 can be controlled by controlling the blower fan 14a. In addition, a blower fan 14b is provided in the outside air introduction pipe 14 upstream of the dryer 11. The blower fan 14b forcibly sends outside air from the outside air introduction pipe 14 to the dryer 11. The flow rate of the outside air sent from the outside air introduction pipe 14 to the dryer 11 can be controlled by controlling the blower fan 14b.

[0030] <Heat exchanger 15> The heat exchanger 15 is configured to perform heat exchange between the first pipe 12 and the outside air introduction pipe 14. The heat exchanger 15 exchanges heat between the exhaust air discharged from the dryer 11 flowing through the first pipe 12 and the outside air introduced through the outside air introduction pipe 14. This allows the temperature of the outside air introduced into the dryer 11 to be increased in advance. Furthermore, the exhaust air discharged from the dryer 11 flowing through the first pipe 12 is supplied to the solvent recovery device 13 via the heat exchanger 15. The heat exchanger 15 lowers the temperature of the exhaust air discharged from the dryer 11. In the solvent recovery device 13, a lower temperature of the exhaust air discharged from the dryer 11 makes it easier for the solvent contained in the exhaust to condense, allowing the organic solvent to be efficiently absorbed into water.

[0031] <Second piping 16> The second pipe 16 is connected to the pipe 13c through which the exhaust gas discharged from the solvent recovery device 13 flows and to the outside air introduction pipe 14 on the upstream side of the heat exchanger 15. The second pipe 16 is a pipe that sends at least a portion of the exhaust gas after passing through the solvent recovery device 13 to the outside air introduction pipe 14. The second pipe 16 introduces a portion of the exhaust gas after passing through the solvent recovery device 13 into the outside air introduction pipe 14, and then passes through the heat exchanger 15 to be supplied to the dryer 11. By introducing a portion of the exhaust gas after passing through the solvent recovery device 13 into the outside air introduction pipe 14 through the second pipe 16, the temperature of the air supplied to the heat exchanger 15 can be stabilized.

[0032] Here, the temperature of the outside air introduced into the outside air introduction pipe 14 is assumed to be about 16°C on average throughout the year. The temperature of the outside air introduced into the outside air introduction pipe 14 varies depending on the season and time. For example, during the daytime in summer, the temperature can be about 35°C. Also, during the nighttime in winter, the temperature can be about -2°C. In this way, the outside air introduced into the outside air introduction pipe 14 is not stable throughout the year. On the other hand, the temperature of the exhaust air discharged from the dryer 11 is about 100°C.

[0033] In the solvent recovery device 13, the temperature of the exhaust air drops as it mixes with the sprayed water, but the temperature of the exhaust air discharged from the solvent recovery device 13 remains at about 40°C, which is higher than the outside air. By introducing a portion of the exhaust air after passing through the solvent recovery device 13 into the outside air inlet pipe 14 via the second pipe 16, the temperature of the outside air introduced into the dryer 11 can be increased, and it is expected that the amount of heat required to heat the outside air by the heater 11b of the dryer 11 can be reduced.

[0034] For example, if the outside air introduced into the outside air inlet pipe 14 is 16°C and the exhaust air discharged from the dryer 11 is 100°C, the exhaust air from the solvent recovery device 13 is not introduced through the second pipe 16, but is instead heat-exchanged directly in the heat exchanger 15. In this case, the outside air may reach approximately 41°C after passing through the heat exchanger 15. This needs to be heated to approximately 115°C in the dryer 11, so a considerable amount of heat is required to heat the outside air with the heater 11b of the dryer 11.

[0035] In contrast, when the exhaust gas from the solvent recovery device 13 is introduced from the second pipe 16 into the outside air introduced into the outside air inlet pipe 14, the temperature of the air supplied to the heat exchanger 15 can be raised to 29°C. Then, the temperature can be raised to 51°C through the heat exchanger 15. This needs to be heated to about 115°C in the dryer 11, but by introducing the exhaust gas from the solvent recovery device 13 into the outside air introduced into the outside air inlet pipe 14 from the second pipe 16, the temperature of the introduced outside air is raised by about 10°C. This is expected to reduce the amount of heat required to heat the outside air by the heater 11b of the dryer 11.

[0036] In this way, the outside air is introduced into the outside air introduction pipe 14, and then mixed with the exhaust gas that has passed through the solvent recovery device 13 and is supplied from the second pipe 16 into the outside air introduction pipe 14. The outside air is then heat exchanged with the exhaust gas from the dryer 11 in the heat exchanger 15. This allows the heat of the exhaust gas from the dryer 11 to be utilized, and the temperature of the outside air to be introduced into the dryer 11 can be increased in advance. This reduces the energy required for the heater 11b of the dryer 11. Furthermore, the temperature of the exhaust gas discharged from the solvent recovery device 13 is stable throughout the year, and the temperature of the outside air supplied through the outside air introduction pipe 14 can be stabilized.

[0037] Here, the exhaust gas that has passed through the solvent recovery device 13 is high-humidity exhaust gas. It is preferable to further include an adjustment valve 16a that adjusts the flow rate of the second pipe 16. By providing the adjustment valve 16a in the second pipe 16, the exhaust gas that has passed through the solvent recovery device 13 and is introduced into the outside air introduction pipe 14 can be adjusted. This makes it possible to control the temperature and dew point of the gas flowing through the outside air introduction pipe 14.

[0038] For example, the control device 40 Outside air intake pipe 14 Of these, The position where the second pipe 16 is connected to the outside air intake pipe 14Preferably, the system is configured to detect at least one of the temperature and dew point of the gas flowing through the outside air introduction pipe 14 downstream of the second piping 16 and upstream of the heat exchanger 15, and to control the opening of the adjustment valve 16a based on the detected value. This makes it possible to adjust the amount of exhaust gas introduced into the outside air introduction pipe 14 through the second piping 16 while feeding back at least one of the temperature and dew point of the gas flowing through the outside air introduction pipe 14.

[0039] The control device 40 is preferably configured to detect the temperature or dew point of the gas flowing through the outside air inlet pipe 14 using a sensor 14c provided in the outside air inlet pipe 14 after the exhaust gas that has passed through the solvent recovery device 13 is introduced through the second pipe 16, and to adjust the opening of the adjustment valve 16a provided in the second pipe 16. The amount of exhaust gas introduced into the outside air inlet pipe 14 through the second pipe 16 is preferably adjusted taking into account the temperature or dew point of the gas flowing through the outside air inlet pipe 14.

[0040] Here, the gas flowing through the outside air introduction pipe 14 is sent to the dryer 11. The higher the temperature of the gas flowing through the outside air introduction pipe 14, the better, but the lower the humidity of the gas flowing through the outside air introduction pipe 14, the better. The exhaust gas introduced into the outside air introduction pipe 14 through the second pipe 16 is high-humidity exhaust gas. For this reason, it is preferable to adjust the amount of exhaust gas introduced into the outside air introduction pipe 14 through the second pipe 16, taking into consideration not only the temperature of the gas flowing through the outside air introduction pipe 14 but also the dew point. More preferably, it is preferable to control the adjustment valve 16a that adjusts the flow rate of the second pipe 16 based on the temperature and dew point of the gas flowing through the outside air introduction pipe 14.

[0041] For example, when the dew point of the gas flowing through the outside air introduction pipe 14 is lower than a predetermined dew point, the aperture of the adjustment valve 16a may be adjusted to increase the amount of exhaust gas introduced into the outside air introduction pipe 14 through the second piping 16. When the dew point of the gas flowing through the outside air introduction pipe 14 is higher than a predetermined dew point, the aperture of the adjustment valve 16a may be adjusted to decrease the amount of exhaust gas introduced into the outside air introduction pipe 14 through the second piping 16. Furthermore, the adjustment valve 16a may be adjusted to close when the dew point of the gas flowing through the outside air introduction pipe 14 becomes higher than a predetermined set value.

[0042] Furthermore, when the temperature of the gas flowing through the outside air introduction pipe 14 is lower than a predetermined temperature, the opening of the adjustment valve 16a may be adjusted so as to increase the amount of exhaust gas introduced into the outside air introduction pipe 14 through the second piping 16. When the temperature of the gas flowing through the outside air introduction pipe 14 is higher than a predetermined temperature, the opening of the adjustment valve 16a may be adjusted so as to decrease the amount of exhaust gas introduced into the outside air introduction pipe 14 through the second piping 16. Furthermore, the adjustment valve 16a may be adjusted so as to close when the temperature of the gas flowing through the outside air introduction pipe 14 becomes higher than a predetermined set value.

[0043] The control device 40 Outside air intake pipe 14 Of these, 14 are outside air intake pipes. The position where the second pipe 16 is connected to downstream of the heat exchanger 15 and upstream of the heat exchanger 15, Outside air intake pipe 14 The concentration of the organic solvent contained in the exhaust gas flowing through the second pipe 16 may be detected, and a process of controlling the opening degree of the adjustment valve 16a based on the detected concentration of the organic solvent is executed. In this way, the amount of exhaust gas introduced into the outside air introduction pipe 14 through the second pipe 16 is adjusted while the concentration of the organic solvent in the outside air introduction pipe 14 is monitored.

[0044] The control device 40 may be configured to detect the concentration of the organic solvent in the gas flowing through the outside air inlet pipe 14 using a sensor 14c provided in the outside air inlet pipe 14 after the exhaust gas that has passed through the solvent recovery device 13 is introduced via the second pipe 16, and adjust the aperture of the adjustment valve 16a provided in the second pipe 16. Here, if the concentration of the organic solvent in the outside air introduced into the dryer 11 exceeds a predetermined concentration, the drying of the mixture slurry in the dryer 11 will be slowed down. The concentration of the organic solvent in the outside air introduced into the dryer 11 is preferably limited to a level that does not slow down the drying of the mixture slurry in the dryer 11. Furthermore, because organic solvents are often hazardous materials, the control device 40 may be configured to shut off the adjustment valve 16a provided in the second pipe 16 if the concentration exceeds a predetermined concentration from a safety standpoint.

[0045] In this manner, the aperture of the regulating valve 16a provided on the second pipe 16 may be adjusted based on at least one of the temperature and dew point of the gas flowing through the outside air inlet pipe 14 and the concentration of the organic solvent after the exhaust gas that has passed through the solvent recovery device 13 is introduced through the second pipe 16. This allows the temperature, dew point, and organic solvent concentration of the outside air introduced into the dryer 11 through the outside air inlet pipe 14 to be controlled. For example, the aperture of the regulating valve 16a provided on the second pipe 16 may be adjusted based on at least one of the temperature and the dew point, and may be controlled so that the regulating valve 16a is closed when the organic solvent concentration exceeds a predetermined concentration. Alternatively, the aperture of the regulating valve 16a may be controlled based on both the temperature and the dew point. For example, the aperture of the regulating valve 16a may be adjusted based on the temperature, and an increase in the aperture of the regulating valve 16a may be suppressed when the dew point exceeds a certain value. In this case, for example, even if the temperature of the gas flowing through the outside air inlet pipe 14 after the exhaust gas that has passed through the solvent recovery device 13 is introduced through the second pipe 16 is lower than a set value for temperature control, if the dew point exceeds a certain value, the aperture of the adjusting valve 16a is prevented from being increased. This makes it possible to prevent the dew point of the gas flowing through the outside air inlet pipe 14 from rising above a certain value. In this way, the aperture of the adjusting valve 16a and the like are preferably controlled so that the quality of the gas flowing through the outside air inlet pipe 14 measured by the sensor 14c is adjusted to a predetermined quality.

[0046] <Heating device 20> In the embodiment shown in FIG. 1 , the outside air introduction pipe 14 further includes a heating device 20. The heating device 20 is located downstream of the heat exchanger 15 in the outside air introduction pipe 14, which sends outside air to the dryer 11. The heating device 20 heats the gas sent to the dryer 11 through the outside air introduction pipe 14 downstream of the heat exchanger 15. In this embodiment, the heating device 20 includes a heat pump 21 and a heat exchange coil 22. The heat exchange coil 22 is installed midway along the outside air introduction pipe 14 and is a heat exchanger, such as a plate-type heat exchanger, that has sufficient capacity to raise the temperature of the outside air introduction pipe 14 above a certain value. The heat pump 21 may be a hot water heat pump unit. For example, the hot water heat pump unit is a heat pump unit equipped with a heat medium circulation system consisting of a heat absorption section and a heat radiation section. The hot water heat pump unit receives heat from an external water heat source or air heat source at the heat absorption section, and radiates the heat from the heat radiation section to a heat transfer system that circulates between the heat pump 21 and the heat exchange coil 22. This allows the required amount of hot water to be supplied to the heat exchange coil 22.

[0047] The heat pump 21 supplies hot water, for example, at about 90°C, to the heat exchange coil 22, which heats the gas flowing through the outside air introduction pipe 14. The outside air heated by the heat exchange coil 22 is then supplied to the dryer 11. When the temperature of the gas flowing through the outside air introduction pipe 14 and discharged from the heat exchanger 15 is about 51°C, the temperature of the outside air supplied to the dryer 11 can be raised to about 80°C by heating the gas flowing through the outside air introduction pipe 14 through the heating device 20. The heat pump 21 can generate a large amount of thermal energy with a small input of energy. In this way, the outside air is further heated by the heating device 20 before being supplied to the dryer 11, so that the energy required by the heater 11b of the dryer 11 can be significantly reduced.

[0048] For example, a sensor 23 provided downstream of the heating device 20 may detect the temperature of the gas flowing through the outside air inlet pipe 14, and the opening of a control valve 24 provided in the heat pump 21 may be controlled accordingly. By controlling the opening of the control valve 24 based on the temperature of the gas flowing through the outside air inlet pipe 14, the amount of heat medium flowing through the heat pump 21 is controlled, thereby heating the gas flowing through the outside air inlet pipe 14 to a stable temperature. In this manner, the amount of heat exchanged between the heat exchange coil 22 and the gas flowing through the outside air inlet pipe 14 may be adjusted. This allows the temperature of the outside air supplied to the dryer 11 to be adjusted. The heat pump 21 can also cool other heat mediums. For example, water can be used as the heat medium. Using water as the heat medium can produce chilled water, for example, at approximately 10°C. This produces chilled water for air conditioning or cooling water for machinery as a by-product, which requires energy to be consumed to cool the water in external equipment. This further reduces energy consumption.

[0049] Here, the heating device 20 is exemplified as a form using a heat pump and a heat exchange coil that can efficiently heat the gas flowing through the outside air introduction pipe 14. The heating device 20 is not limited to this, and may be any device that heats the gas sent to the dryer 11 through the outside air introduction pipe 14 downstream of the heat exchanger 15.

[0050] In this way, by introducing the exhaust gas from the solvent recovery device 13 into the outside air inlet pipe 14, the temperature of the outside air introduced into the dryer 11 through the outside air inlet pipe 14 can be increased. This reduces the energy required by the heater 11b of the dryer 11. Furthermore, by using the heating device 20 to heat the outside air supplied to the dryer 11 via the heat exchanger 15, the energy required by the heater 11b of the dryer 11 can be significantly reduced. From the perspective of reducing the energy required by the heater 11b of the dryer 11, simply introducing the exhaust gas from the solvent recovery device 13 into the outside air inlet pipe 14 and simply heating the exhaust gas by the heating device 20 are both effective. By introducing the exhaust gas from the solvent recovery device 13 into the outside air inlet pipe 14 via the second pipe 16, heating the exhaust gas via the heat exchanger 15, and further heating the exhaust gas by the heating device 20, the capacity required for the heating device 20 can be reduced. This allows the heating device 20 to be made more compact, thereby reducing equipment costs and running costs.

[0051] Here, the electrode manufacturing method includes a drying step and a solvent recovery step. The drying step is a step of drying a sheet-shaped current collector coated with a mixture slurry in which electrode active material particles are dispersed in an organic solvent. In the electrode manufacturing equipment 10 described above, the drying step is embodied by the dryer 11. The solvent recovery step is a step of spraying water onto the exhaust gas discharged in the drying step to dissolve the organic solvent contained in the exhaust gas in the water. In the electrode manufacturing equipment 10 described above, the solvent recovery step is embodied by the solvent recovery device 13. In the drying step, it is preferable that a portion of the exhaust gas after spraying water in the solvent recovery step is mixed with outside air and heat exchanged with the exhaust gas discharged in the drying step before being introduced into the dryer 11. This makes it possible to increase the temperature of the outside air introduced into the dryer 11. This reduces the energy required by the heater 11b of the dryer 11.

[0052] The amount of the exhaust gas after water is sprayed in the solvent recovery process that is mixed with outside air may be adjusted based on the dew point of the gas after mixing. Furthermore, the amount of the exhaust gas after water is sprayed in the solvent recovery process that is mixed with outside air may be adjusted based on the concentration of the organic solvent in the gas after mixing. The amount of the exhaust gas after water is sprayed in the solvent recovery process that is mixed with outside air may be adjusted based on the dew point and the concentration of the organic solvent in the gas after mixing. For example, the amount of the exhaust gas after water is sprayed in the solvent recovery process that is mixed with outside air may be adjusted based on the temperature of the gas after mixing. The amount of the exhaust gas after water is sprayed in the solvent recovery process that is mixed with outside air may be adjusted based on the temperature and the concentration of the organic solvent in the gas after mixing. The amount of the exhaust gas after water is sprayed in the solvent recovery process that is mixed with outside air may be adjusted based on the temperature, dew point, and the concentration of the organic solvent in the gas after mixing.

[0053] In the drying step of the electrode manufacturing method, outside air may be heat-exchanged with the exhaust gas discharged in the drying step, and the outside air may be further heated before being introduced into the dryer. This reduces the energy required by the heater 11b of the dryer 11. For example, in the drying step, a gas obtained by mixing a portion of the exhaust gas after water has been sprayed in the solvent recovery step with outside air may be heat-exchanged with the exhaust gas discharged in the drying step, and the gas may be further heated before being introduced into the dryer. This reduces the energy required by the heater 11b of the dryer 11 significantly.

[0054] The invention disclosed herein has been described in various ways. Unless otherwise specified, the embodiments described herein do not limit the present invention. Furthermore, the embodiments of the invention disclosed herein can be modified in various ways, and each component and each process described herein can be omitted or combined as appropriate, unless a particular problem arises.

[0055] As described above, this specification includes the disclosures set forth in the following sections. Section 1: A dryer and a solvent recovery device that recovers an organic solvent contained in the exhaust gas discharged from the dryer by dissolving it in water; a first pipe that sends exhaust gas discharged from the dryer to the solvent recovery device; an outside air introduction pipe for introducing outside air and sending it to the dryer; a heat exchanger configured to perform heat exchange between the first pipe and the outside air introduction pipe; a pipe through which the exhaust gas after passing through the solvent recovery device is discharged; and a second pipe connected to the outside air introduction pipe on an upstream side of the heat exchanger, and for sending at least a portion of the exhaust gas after passing through the solvent recovery device to the outside air introduction pipe. Equipped with The dryer is A drying oven, a heater that heats the air supplied through the outside air introduction pipe and supplies the air into the drying oven; a conveying device that conveys a sheet-like current collector coated with a mixture slurry in which electrode active material particles are dispersed in an organic solvent (NMP) along a predetermined conveying path in the drying furnace; Equipped with Electrode manufacturing equipment.

[0056] Section 2: Item 1. The electrode manufacturing facility according to item 1, further comprising an adjusting valve for adjusting the flow rate of the second pipe.

[0057] Section 3: Further comprising a control device, The control device The aforementioned Outside air intake pipe Among these, the outside air introduction pipe The position where the second pipe is connected to detecting at least one of a temperature and a dew point of the gas flowing through the outside air inlet pipe downstream of the outside air inlet pipe and upstream of the heat exchanger; A process for controlling the opening degree of the regulating valve is executed based on at least one of the detected temperature and the dew point. Electrode manufacturing equipment described in item 2.

[0058] Section 4: Further comprising a control device, The control device The aforementioned Outside air intake pipe Among these, the outside air introduction pipe The position where the second pipe is connected to downstream of the heat exchanger and upstream of the heat exchanger, Outside air intake pipe detecting the concentration of the organic solvent contained in the exhaust gas flowing through the a process of controlling the opening degree of the adjusting valve based on the detected concentration of the organic solvent is executed. Electrode manufacturing equipment described in item 2.

[0059] Section 5: Further comprising a control device, The control device The aforementioned Outside air intake pipe Among these, the outside air introduction pipe The position where the second pipe is connected to detecting at least one of a temperature and a dew point of the gas flowing through the outside air inlet pipe and a concentration of the organic solvent downstream of the outside air inlet pipe and upstream of the heat exchanger; a process of controlling the opening degree of the adjusting valve based on at least one of the detected temperature and the dew point and the concentration of the organic solvent is executed. Electrode manufacturing equipment described in item 2.

[0060] Item 6: 6. The electrode manufacturing facility according to any one of items 1 to 5, wherein an outside air introduction pipe for sending outside air to the dryer further includes a heating device downstream of the heat exchanger.

[0061] Section 7: Item 7. The electrode manufacturing equipment according to item 6, wherein the heating device is a heat exchange coil connected to a heat pump.

[0062] Section 8: A dryer and a solvent recovery device that recovers an organic solvent contained in the exhaust gas discharged from the dryer by dissolving it in water; a first pipe that sends exhaust gas discharged from the dryer to the solvent recovery device; an outside air introduction pipe for introducing outside air and sending it to the dryer; a heat exchanger configured to perform heat exchange between the first piping and the outside air introduction pipe; Equipped with The dryer is A drying oven, a heater that heats the air supplied through the outside air introduction pipe and supplies the air into the drying oven; a conveying device that conveys a sheet-like current collector coated with a mixture slurry in which electrode active material particles are dispersed in an organic solvent along a predetermined conveying path in the drying furnace; Equipped with The outside air introduction pipe that sends outside air to the dryer is equipped with a heating device downstream of the heat exchanger. Electrode manufacturing equipment.

[0063] Section 9: Item 9. The electrode manufacturing equipment according to item 8, wherein the heating device is a heat exchange coil connected to a heat pump.

[0064] Section 10: a drying step of drying a sheet-shaped current collector coated with a mixture slurry in which electrode active material particles are dispersed in an organic solvent; a solvent recovery step of spraying water onto the exhaust gas discharged in the drying step to dissolve the organic solvent contained in the exhaust gas in the water; Including, In the drying step, a part of the exhaust gas after spraying water in the solvent recovery step is mixed with outside air, and is heat exchanged with the exhaust gas discharged in the drying step before being introduced into the dryer. Electrode manufacturing method.

[0065] Section 11: Item 11. An electrode manufacturing method according to item 10, wherein the amount of the exhaust gas after water spraying in the solvent recovery step mixed with the outside air is adjusted based on at least one of the temperature and dew point of the mixed gas.

[0066] Section 12: Item 11. An electrode manufacturing method according to item 10, wherein the amount of the exhaust gas after water spraying in the solvent recovery step that is mixed with the outside air is adjusted based on the concentration of the organic solvent in the mixed gas.

[0067] Section 13: Item 11. An electrode manufacturing method according to item 10, wherein the amount of the exhaust gas after water spraying in the solvent recovery step mixed with the outside air is adjusted based on at least one of the temperature and dew point of the mixed gas and the concentration of the organic solvent.

[0068] Section 14: Item 14. The electrode manufacturing method according to any one of Items 10 to 13, wherein in the drying step, a part of the exhaust gas after spraying water in the solvent recovery step is mixed with outside air to produce a gas, which is then heat exchanged with the exhaust gas discharged in the drying step, further heated, and then introduced into the dryer.

[0069] Section 15: a drying step of drying a sheet-shaped current collector coated with a mixture slurry in which electrode active material particles are dispersed in an organic solvent; a solvent recovery step of spraying water onto the exhaust gas discharged from the dryer to dissolve the organic solvent contained in the exhaust gas into the water; Including, In the drying step, the outside air is heat exchanged with the exhaust air discharged in the drying step, and is further heated before being introduced into the dryer. Electrode manufacturing method. [Explanation of symbols]

[0070] 10 Electrode manufacturing equipment 11 Dryer 11a Drying oven 11a1 Entrance 11a2 exit 11b Heater 11c Transport device 11d Coating equipment 12 First piping 12a Blower fan 13 Solvent recovery device 13a Water supply piping 13b Reprocessing facility 13c: A pipe through which the exhaust gas discharged from the solvent recovery device 13 flows. 14 Fresh air intake pipe 14a Blower fan 14b Blower fan 14c sensor 15 Heat exchanger 16 Second piping 16a Regulating valve 20 Warming device 21 Heat Pump 22 Heat exchange coil 23 Sensors 24 Regulating valve 40 Control device 61a Collection tank 61a~61d Collection tank 61d Recovery tank 62 A pipe through which the exhaust gas discharged from the dryer 11 flows in the solvent recovery device 13 62a~62d Filler 63a~63d Pump

Claims

1. A dryer and a solvent recovery device that recovers an organic solvent contained in the exhaust gas discharged from the dryer by dissolving it in water; a first pipe that sends exhaust gas discharged from the dryer to the solvent recovery device; an outside air introduction pipe for introducing outside air and sending it to the dryer; a heat exchanger configured to perform heat exchange between the first pipe and the outside air introduction pipe; a pipe through which the exhaust gas after passing through the solvent recovery device is discharged; and a second pipe connected to the outside air introduction pipe on an upstream side of the heat exchanger, and for sending at least a portion of the exhaust gas after passing through the solvent recovery device to the outside air introduction pipe. Equipped with The dryer is A drying oven, a heater that heats the air supplied through the outside air introduction pipe and supplies the air into the drying oven; a conveying device that conveys a sheet-like current collector coated with a mixture slurry in which electrode active material particles are dispersed in an organic solvent along a predetermined conveying path in the drying furnace; Equipped with Electrode manufacturing equipment.

2. The electrode manufacturing facility according to claim 1 , further comprising an adjusting valve for adjusting the flow rate of the second pipe.

3. Further comprising a control device, The control device At least one of a temperature and a dew point of the gas flowing through the outside air introduction pipe is detected downstream of a position where the second pipe is connected to the outside air introduction pipe and upstream of the heat exchanger, A process for controlling the opening degree of the regulating valve is executed based on at least one of the detected temperature and the dew point.

3. An electrode manufacturing facility according to claim 2.

4. Further comprising a control device, The control device detecting a concentration of the organic solvent contained in the exhaust gas flowing through the outside air inlet pipe, at a position in the outside air inlet pipe downstream of a position where the second pipe is connected to the outside air inlet pipe and upstream of the heat exchanger; a process of controlling the opening degree of the adjusting valve based on the detected concentration of the organic solvent is executed.

3. An electrode manufacturing facility according to claim 2.

5. Further comprising a control device, The control device detecting at least one of a temperature and a dew point of the gas flowing through the outside air inlet pipe and a concentration of the organic solvent, at a location in the outside air inlet pipe downstream of a position where the second pipe is connected to the outside air inlet pipe and upstream of the heat exchanger; a process of controlling the opening degree of the adjusting valve based on at least one of the detected temperature and the dew point and the concentration of the organic solvent is executed.

3. An electrode manufacturing facility according to claim 2.

6. 6. The electrode manufacturing facility according to claim 1, wherein an outside air inlet pipe for sending outside air to the dryer further includes a heating device downstream of the heat exchanger.

7. 7. The electrode manufacturing facility according to claim 6, wherein the heating device is a heat exchange coil connected to a heat pump.

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