JP2018149474A - Manufacturing device and manufacturing method of wet granulated body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing device and a manufacturing method of a wet granulated body, eliminating adhesion of a raw material powder to a vessel wall surface and providing the wet granulated body uniform in compounding ratio of the raw material powder and a wet solvent.SOLUTION: A manufacturing device of a wet granulated body has a rigid vessel, a solvent supply part, and a stirring blade, and further has a vibration part for vibrating the entire wall surface of the rigid vessel. A first stirring process (S2) for stirring the entire wall surface of the rigid vessel while vibrating at a vibration frequency selected from a range of 1 to 10 kHz, a solvent supply process (S3) for supplying the wet solvent and a second stirring process (S4) for stirring the entire wall surface of the rigid vessel at a vibration frequency selected from a range of 0.1 to 10 kHz are conducted.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a manufacturing apparatus and a manufacturing method for a wet granulated body in which powder is wetted with a liquid component.

  Conventionally, powder is used as a raw material and the aggregate is solidified into a predetermined shape and used. In order to solidify an aggregate of powder into a predetermined shape, the powder is generally kneaded with a liquid component to form a fluid, and the fluid is molded and then dried. In recent years, in order to simplify the drying process, the same has been done with wet powders with less liquid components. One example where such a technique is used is the production of an electrode plate in a battery. This is because the electrode plate of a battery is an aggregate of electrode active material powders in many cases, and a thin electrode active material layer is formed on a current collector foil.

  As an example of a conventional technique for producing the above wet powder or wet granulated material, one described in Patent Document 1 can be cited. In the technique of this document, a bottomed cylindrical rubber container is used. An inclined rotating plate is attached to the lower part of the rubber container, and a stirring bar is attached to the inclined rotating plate toward the inside of the rubber container. When the inclined rotating plate is rotated in this configuration, the rubber container is swayed and the stirring bar rotates along the conical surface. Thus, the contents of the rubber container, that is, the powder and the liquid are mixed. Since the rubber container is shaken during stirring, it is said that there is little adhesion of the contents to the container wall.

JP 2007-222861 A

  However, the conventional techniques described above have the following problems. In the technology of this document, there is little adhesion of the contents to the container wall surface. This is because the powder always adheres to the wall of the container when the powder is put into the rubber container. After that, even if the rubber container is shaken, the powder once adhered does not completely detach from the container wall. For this reason, the wet powder produced by the technique of the same document contains not a few portions where the blending ratio is not uniform. For this reason, when this was coated in a thin layer on a flat plate, transparent spots and streaky defective spots were likely to occur.

  The present invention has been made to solve the above-described problems of the prior art. That is, the problem is that a wet granulated product manufacturing apparatus and a wet granulated product in which the adhesion of the raw material powder to the container wall surface is eliminated and a uniform mixing ratio of the raw material powder and the wet solvent can be obtained. It is to provide a manufacturing method.

  An apparatus for producing a wet granulated body according to an aspect of the present invention includes a rigid container that contains raw powder of the wet granulated body, a solvent supply unit that supplies the wet solvent into the rigid container, and a stored item in the rigid container. An apparatus having a stirring blade that stirs and a drive unit that drives the stirring blade, and includes a vibration unit that vibrates the entire wall surface of the rigid container, and a vibration control unit that controls the vibration frequency of the vibration unit. The vibration control unit performs vibration before supplying the wet solvent from the solvent supply unit to the contents in the rigid container at a vibration frequency selected from the range of 1 to 10 kHz, The vibration after supplying the wet solvent to the contents in the container is configured to be performed at a vibration frequency selected from the range of 0.1 to 10 kHz.

  Further, the method for producing a wet granule according to another aspect of the present invention is a method for producing a wet granulation by adding a wet solvent to the raw powder of the wet granulation, and comprising the entire wall surface of the rigid container. In the rigid container after the first stirring step, and after the first stirring step, the raw powder of the wet granulated material contained in the rigid container is stirred while vibrating at a vibration frequency selected from the range of 1 to 10 kHz. A solvent supply step for supplying a wet solvent to the container, and after the solvent supply step, the whole wall surface of the rigid container is vibrated at a vibration frequency selected from a range of 0.1 to 10 kHz, and the contents in the rigid container are stirred. And a second stirring step.

  In each of the above embodiments, first, the first stirring step is performed in a dry state in which the raw material powder is accommodated in the rigid container and the wet solvent is not accommodated. That is, the contents in the rigid container are stirred with the stirring blade by driving the stirring blade with the drive unit. At that time, the entire wall surface of the rigid container is vibrated by the vibrating portion. This prevents the raw material powder from adhering to the wall surface of the rigid container so that the entire raw material powder is uniformly stirred. Thereafter, a solvent supply step is performed. That is, the solvent is supplied from the solvent supply unit into the rigid container. As a result, the contents in the rigid container become wet. Thereafter, the second stirring step is performed. Also at this time, the entire wall surface of the rigid container is vibrated. This prevents the contents from adhering to the wall surface of the rigid container so that the entire contents can be uniformly stirred.

  Here, the vibration frequency in the first stirring step (before supplying the wet solvent) is a vibration frequency selected from the range of 1 to 10 kHz. In other words, vibration at a high frequency of 1 kHz is applied at the minimum. Thereby, even if the contents in the rigid container are in a dry state with high chargeability, they are prevented from adhering to the wall surface. On the other hand, the vibration frequency in the second stirring step (after supplying the wet solvent) is a vibration frequency selected from the range of 0.1 to 10 kHz. That is, a frequency not so high as 0.1 to 1 kHz may be used. This is because the charge in the rigid container is lowered and the adhesion to the wall surface is also lowered. In this way, a wet granulated product having a high uniformity of the mixing ratio of the components can be obtained.

  According to this configuration, a wet granulated body manufacturing apparatus and manufacturing method that eliminates the adhesion of the raw material powder to the container wall surface and that provides a wet granulated body with a uniform mixing ratio of the raw material powder and the wet solvent. Is provided.

It is a see-through | perspective perspective view which shows the structure of the manufacturing apparatus of the wet granulation body which concerns on embodiment. It is a see-through | perspective perspective view which shows the comparative example which has arrange | positioned the excitation in the low position. It is a flowchart explaining the procedure which manufactures a wet granulation body with the manufacturing apparatus which concerns on embodiment.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below in detail with reference to the accompanying drawings. In this embodiment, the present invention is embodied as the wet granulated body manufacturing apparatus 1 shown in FIG. The manufacturing apparatus 1 in FIG. 1 includes a granulating pot 2, a vibration unit 3, a stirring blade 4, a spray nozzle 5, and a motor 6.

  The granulation pot 2 is a cylindrical container closed on both the top and bottom surfaces. The granulating pot 2 is made of a rigid material made of metal or alloy such as stainless steel or aluminum. The vibration unit 3 is a vibrator that applies elastic vibration to the granulating pot 2. The vibration unit 3 is attached to a plurality of locations on the wall surface of the granulating pot 2. The stirring blade 4 is a member that is located inside the granulating pot 2 and that stirs the contents of the granulating pot 2 by rotating. The agitating blade 4 is connected to a motor 6 by a shaft 7 and receives rotational driving from the motor 6. The spray nozzle 5 supplies liquid from above into the granulating pot 2. The manufacturing apparatus 1 is further provided with a control unit 8. The vibration unit 3, the spray nozzle 5, and the motor 6 are under the control of the control unit 8.

  Here, the range in which the vibration is applied by the vibration unit 3 in the granulating pot 2 will be described. For example, as shown in FIG. 2, it is conceivable to arrange the excitation unit 3 at a position near the lower end of the entire size in the height direction of the granulating pot 2. However, in this case, even if the material of the granulating pot 2 is a rigid material, the vibration does not necessarily reach the entire wall surface of the granulating pot 2. In the example of FIG. 2, the vibration only affects the lower range A of the entire size in the height direction of the granulating pot 2. On the contrary, if the vibration unit 3 is arranged near the upper end of the granulating pot 2, the vibration can only reach the upper range of the granulating pot 2.

  However, in this embodiment, the position where the excitation unit 3 is attached is set to approximately the center of the size in the height direction of the granulating pot 2. Due to this arrangement and the above-described material of the granulation pot 2, the vibration by the vibration unit 3 extends over the entire wall surface of the granulation pot 2.

  This can be understood immediately by actually driving the excitation unit 3. That is, when some powder substance having a certain amount of static electricity is accommodated in the granulating pot 2, a lot of powder adheres to the wall surface of the granulating pot 2. When the excitation unit 3 is driven in this state, the powder immediately drops away from the wall surface in the range where the vibration is applied, but the powder remains attached in the range where the vibration is not applied. In the example of FIG. 2, the powder falls only in the range A, but in the configuration of this embodiment of FIG. 1, the powder falls on the entire wall surface.

  In addition, since the vibration of the granulating pot 2 due to the vibration of the vibration unit 3 is a standing wave vibration, there are places where “nodes” of the vibration exist everywhere. However, this can be understood immediately by driving the excitation unit 3, but the powder does not remain at the node. In the present embodiment shown in FIG. 1, the powder falls on the entire wall surface without any remaining portion. The same applies to the range A in the example of FIG. Therefore, it does not mean that no vibration is applied to the node of the standing wave vibration.

  The procedure of the manufacturing method of the wet granule in the manufacturing apparatus 1 of this embodiment configured as described above will be described with reference to FIG. First, the raw powder of the wet granulated material is stored in the granulating pot 2 (S1). “Active material” and “binder” in FIG. 3 are examples of raw material powders. At this time, the wet solvent is not put into the granulating pot 2. At this time, a part of the powder adheres to the wall surface of the granulating pot 2 depending on the charging state of the raw material powder.

  Then, the agitation vessel 2 is agitated by the agitation blade 4. That is, the stirring blade 4 is rotated in the granulating pot 2 by driving the stirring blade 4 with the motor 6. At this time, vibration by the vibration unit 3 is also performed (S2). This is the first stirring step. Even if a part of the powder adheres to the wall surface of the granulating pot 2 due to the vibration, all the powder is peeled off from the wall surface. Even if there is powder that contacts the wall surface during stirring, it does not adhere. Agitation is performed in this state. For this reason, the contents inside the granulation pot 2 are in a state where the powder of the active material and the powder of the binder are uniformly mixed. This is because there is no powder that remains attached to the wall and cannot be stirred.

  In this 1st stirring process, let the vibration frequency by the vibration part 3 be a frequency selected from the range of 1-10 kHz. The reason why the lower limit frequency here is 1 kHz is to ensure that the powder is peeled off the wall surface. That is, since the contents of the granulating pot 2 at this time are in a dry state, they are easily charged and easily attached to the wall surface. In order to peel off the powder in such a situation from the wall surface, the vibration frequency needs to be a certain high frequency. For this purpose, a frequency of at least 1 kHz is necessary. On the other hand, with respect to the upper limit frequency, even if the frequency is too high, there is no particular merit, and if the frequency is too high, the energy input to the excitation unit 3 becomes excessive, and the problem of heat generation in the excitation unit 3 also occurs. Since it cannot be ignored, it is set to 10 kHz.

  And the wet solvent is supplied with respect to the inside of the granulation pot 2 by the spray nozzle 5 (S3). “Water” in FIG. 3 is an example of a wet solvent. This is the solvent supply step. Due to the supply of the wet solvent, the contents of the granulation pot 2 become a mixture of the raw material powder and the wet solvent. In this solvent supply step, the stirring by the stirring blade 4 may be continued or may be temporarily stopped. The vibration by the vibration unit 3 may be continued or may be temporarily stopped.

  Further, stirring by the stirring blade 4 and vibration by the vibration unit 3 are performed (S4). This is the second stirring step. In the second stirring step, the entire contents of the granulating pot 2 are stirred to form a granular granulated body. The granulated body thus formed is in a wet state containing a wet solvent. The mixing ratio of the raw material powder and the wet solvent, that is, the solid content ratio becomes uniform throughout the granulated body. Of course, as described above, the mixing ratio of the active material and the binder is also uniform. This is because the vibration by the vibration unit 3 is also performed in the second stirring step.

  In this 2nd stirring process, let the vibration frequency by the vibration part 3 be the frequency selected from the range of 0.1-10 kHz. That is, the lower limit frequency in the second stirring step is lower than the lower limit frequency in the first stirring step. This is because the contents of the granulating pot 2 at this time are in a wet state unlike the time of the first stirring step. As a result, the charging property is lowered and the adhesion to the wall surface is also lowered. For this reason, even low frequency vibrations in the range of 0.1 to 1 kHz are sufficient. On the other hand, the upper limit frequency is the same frequency because the situation is not particularly different from that in the first stirring step.

  When entering the second half of the second stirring step, the phenomenon in the granulating pot 2 changes from the formation of the granulated body to the refinement. If it comes to this stage, it is only necessary to stop the vibration by the vibration unit 3 and continue the stirring by the stirring blade 4. This is because the granulated body has a dumpling shape, so it is heavier than the individual powders and will peel off naturally due to gravity even when it comes into contact with the wall surface. However, even if this stage is reached, the vibration by the vibration unit 3 may be continued.

  In this way, a wet granule having a uniform blending ratio of the raw material powder and the wet solvent can be obtained. In particular, a good wet granule can be obtained even when the weight ratio (solid content ratio) of the raw material powder to the entire wet granulation is 70% or more and the amount of the wet solvent is small. When the obtained wet granulated body is taken out from the granulation pot 2 and applied to a foil-like substrate, a high-quality coating layer having neither a transparent part nor a streak-like defective part can be obtained. For coating, for example, a triaxial roll film forming apparatus as shown in FIG. 2 of JP-A-2017-037714 can be used.

  Hereinafter, the Example in the case of manufacturing the wet granulation for formation of the negative electrode active material layer of a lithium ion secondary battery using the manufacturing apparatus 1 of this form is described with the comparative example. Various conditions in the production of the wet granulated body in this example and the comparative example were as follows.

・ Raw material powder (active material) → Graphite ・ Raw material powder (binder) → Carboxymethylcellulose ・ Combination ratio of active material and binder → 97: 3 to 99.7: 0.3 (weight ratio)
・ Wet solvent → Water ・ Set solid content → 72%
・ Capacity of granulating pot 2 → 1 liter ・ Measurement of solid content in granulated material → Precision electronic balance and dryer / film forming device → Triaxial roll film forming device (Rix)

  Table 1 shows the detailed conditions and test results in the individual examples and comparative examples. The “vibration area ratio”, “first frequency”, and “second frequency” columns in Table 1 are detailed conditions, and “NV variation”, “film formability”, and “battery characteristics” columns are test results. It is. Of each column for detailed conditions, the part shown in italics is outside the preferred range for each condition.

  The column of “vibration area ratio” in Table 1 shows the area ratio occupied by the portion of the wall surface of the granulation pot 2 to which vibration is applied by the vibration unit 3. As described above, the vibration area ratio can be easily measured by driving the excitation unit 3 in a state in which an appropriate charged powder is adhered to the wall surface of the granulating pot 2. 100% was defined as the powder falling on the entire wall surface (Examples 1 to 6, Comparative Examples 1 and 2). Comparative examples 3 and 4 were those in which the powder did not fall and could not be 100%.

  The column of “first frequency” indicates the vibration frequency of the vibration unit 3 in the first stirring step. Except for the three examples of Examples 1 and 2 and Comparative Example 1, the upper limit of the preferred frequency range was fixed. In the three examples of Examples 1 and 2 and Comparative Example 1, the frequency was lower than that. Of these, Comparative Example 1 has a frequency lower than the lower limit frequency.

  The column “second frequency” indicates the vibration frequency of the vibration unit 3 in the second stirring step. Except for Examples 4 to 6 and Comparative Example 2 other than the four, they were fixed at the upper limit of the preferred frequency range described above. In the four examples of Examples 4 to 6 and Comparative Example 2, the frequency was lower than that. Of these, Comparative Example 2 has a frequency lower than the lower limit frequency. As in the first and second embodiments, the first frequency may be lower than the second frequency.

  The column of “NV variation” indicates whether or not the variation is good when five samples are taken from the finished wet granulated material and the respective NV (solid content ratio) values are measured. The solid content was determined from the difference between before and after drying of the weight measured with a precision electronic balance after the sample was dried with a dryer. “○” indicates that the maximum variation (the ratio of the difference between the maximum and minimum values to the average value) of the five measured NV values was within 1%, and “×” indicates that it exceeded 1%. It was.

  The column of “film formability” indicates whether film formability is good or not when the finished wet granulated material is coated on a copper foil with the above-mentioned film forming machine. “○” indicates that the film could be formed and neither the transparent part nor the streak-like defective part was formed, and “×” represents that the film could not be formed or the transparent part or the streak-like defective part was formed. It was.

  The “Battery characteristics” column shows the quality of the test results of the electrical characteristics (capacity, battery resistance, etc.) of the lithium ion secondary battery produced by making a negative electrode with the finished wet granulated material and combining it with the positive electrode, etc. . “○” indicates that the characteristics of the battery produced using the conventional active material paste having a low NV value were better, and the film could not be formed or the electrical characteristics did not reach that of the conventional type. Was marked “x”.

  Table 1 shows the following. First, in the examples 1 to 6, the three test results are all “◯”, whereas in the comparative examples 1 to 4, the three test results are all “x”. Therefore, the reason why the test results of Comparative Examples 1 to 4 were not good will be considered.

  In the thing of the comparative example 1, the 1st frequency (vibration frequency at the time of a 1st stirring process) was a frequency lower than the lower limit frequency. Therefore, it is considered that a part of the raw material powder remained attached to the wall surface of the granulating pot 2 during the first stirring step. For this reason, it is considered that the raw material powder adhering to the wall surface of the granulating pot 2 was not stirred, and mixing of the active material and the binder remained insufficient. Furthermore, it is thought that there was not much mixing with the wet solvent. Thus, it is understood that even when the stirring in the second stirring step was performed, the NV of the finished wet granulated material was not uniform.

  In the case of Comparative Example 2, the stirring during the first stirring step should be good. However, the second frequency (vibration frequency during the second stirring step) was lower than the lower limit frequency. Therefore, it is considered that a phenomenon in which part of the contents of the granulation vessel 2 did not adhere to the wall surface and peel off during the second stirring step occurred. Since the adhering contents are not stirred after that, it is considered that the NV of the finished wet granulated material varies. During the second stirring step, the contents are wet, so the adhesion to the wall due to static electricity should be reduced, but it is still understood that the vibration frequency is too low at 0.05 kHz. The

  In the comparative examples 3 and 4, it is considered that a part of the wall surface of the granulating pot 2 was not vibrated during both the first stirring process and the second stirring process. For this reason, it is considered that the raw material powder remained adhered to the portion of the wall surface that did not vibrate during both the first stirring step and the second stirring step. For this reason, it is understood that NV of the completed wet granulated material was not uniform.

  On the other hand, in Examples 1 to 6, it is understood that the raw material powder did not adhere to the wall surface of the granulating pot 2 at all during the first stirring process and the second stirring process. As a result, it is understood that the entire contents of the granulation pot 2 are sufficiently agitated, leading to good results. The above is an example.

  As described in detail above, according to the present embodiment and examples, the stirring step is performed when the raw material powder (active material and binder) and the wet solvent (water) are mixed to form a wet granulated body. Are divided into a first stirring step performed in a dry state and a second stirring step performed after being in a wet state. In both the first stirring step and the second stirring step, stirring is performed while applying vibrations having a frequency selected from each appropriate frequency range to the entire wall surface of the granulating pot 2. As a result, stirring is performed without generating raw material powder that does not participate in stirring, and a wet granulated body with high uniformity of the blending ratio is obtained. A method for producing a wet granulated body is realized.

  Note that this embodiment is merely an example, and does not limit the present invention. Therefore, the present invention can naturally be improved and modified in various ways without departing from the gist thereof. For example, the number of vibration units 3 and spray nozzles 5 may not be as shown in FIG. Further, the wet granulated material to be produced is not limited to the one for forming the negative electrode active material layer. It may be for forming a positive electrode active material layer, or may be for an application other than a battery.

DESCRIPTION OF SYMBOLS 1 Manufacturing apparatus 2 Granulation pot 3 Shaking part 4 Stirring blade 5 Spray nozzle 6 Motor 8 Control part

Claims (2)

A rigid container for storing the raw material powder of the wet granulated body, a solvent supply unit for supplying a wet solvent into the rigid container, a stirring blade for stirring the contents in the rigid container, and driving the stirring blade An apparatus for producing a wet granulated body having a drive unit,
An excitation unit for exciting the entire wall surface of the rigid container;
A vibration control unit that controls a vibration frequency of the excitation unit;
The vibration control unit
Excitation before supplying the wet solvent from the solvent supply unit to the contents in the rigid container is performed at a vibration frequency selected from the range of 1 to 10 kHz,
The vibration after supplying the wet solvent from the solvent supply unit to the contents in the rigid container is configured to be performed at a vibration frequency selected from the range of 0.1 to 10 kHz. An apparatus for producing a wet granulated product. A method for producing a wet granulated product by adding a wet solvent to a raw powder of the wet granulated product to obtain a wet granulated product,
A first stirring step of stirring the raw material powder of the wet granulated material accommodated in the rigid container while vibrating the entire wall surface of the rigid container at a vibration frequency selected from the range of 1 to 10 kHz;
A solvent supply step of supplying a wet solvent into the rigid container after the first stirring step;
A second stirring step of stirring the contents in the rigid container while vibrating the entire wall surface of the rigid container at a vibration frequency selected from the range of 0.1 to 10 kHz after the solvent supply step; A method for producing a wet granulated product.

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