Patent ID: 12187531

DETAILED DESCRIPTION OF EMBODIMENTS

One embodiment of the disclosure will be described with reference to the drawings. In the drawings referred to below, the same reference signs are assigned to the same or corresponding members.

FIG.1is a cross-sectional view schematically showing a wet particle storage tank according to one embodiment of the disclosure. The wet particle storage tank1is favorably used for storage of wet particles used in electrode sheets of power storage cells, for example.

The wet particle storage tank1includes a tank body100and a crushing member200.

The tank body100can store wet particles WP containing particles and solvent. The solid content of the wet particles WP is, for example, between 70% and 84%. The solid content is measured by the dry weight method, for example. The wet particles WP may be granular, flaky, or clay-like. The grain size of the wet particles WP is, for example, 4 mm or less. The tank body100of this embodiment can store the wet particles WP in a condition where the wet particles WP are divided into the upper and lower masses. The tank body100has an upper storage section110, a lower storage section120, and a bridge forming section130. For example, the wet particles WP are in a granular form (like wet sand) with a certain viscosity, not in a paste form. Thus, the wet particles WP do not adhere to each other and immediately fall from the upper storage section110to the lower storage section120, but the wet particles WP allow the bridge forming section130to be formed. When the wet particles WP are pressed, the wet particles WP are brought into a state like bread dough because the wet particles WP have a certain viscosity.

The upper storage section110has a supply port112through which the wet particles WP are supplied. The supply port112opens upward. The upper storage section110is formed like a tube. More specifically, the upper storage section110is formed in a cylindrical shape.

The lower storage section120is located below the upper storage section110. The lower storage section120has a discharge port122through which the wet particles WP are discharged. The discharge port122opens downward. The lower storage section120is formed like a tube. More specifically, the lower storage section120is formed in a cylindrical shape. The central axis of the lower storage section120is located on an extension of the central axis of the upper storage section110. Namely, the upper storage section110and lower storage section120are formed in a cylindrical shape having the central axis extending in a direction (the vertical direction inFIG.1) connecting the upper storage section110and the lower storage section120.

A supply port124through which the wet particles WP are supplied may be provided on the upper part of the lower storage section120.

The bridge forming section130is provided between the upper storage section110and the lower storage section120. The bridge forming section130facilitates formation of a bridge BR (a region where the wet particles WP are stuck and solidified) (seeFIG.1) by the wet particles WP so that falling of the wet particles WP from the upper storage section110to the lower storage section120is blocked. In other words, the bridge forming section130forms a space S between the wet particles WP stored in the upper storage section110and the wet particles WP stored in the lower storage section120.

The bridge forming section130has a connecting section132that connects the upper storage section110and the lower storage section120. In this embodiment, the connecting section132has a neck portion132a. The cross-sectional area of the neck portion132ain a plane perpendicular to the above-mentioned central axis is smaller than the cross-sectional area of a lower end portion111of the upper storage section110in the plane perpendicular to the central axis, and is also smaller than the cross-sectional area of an upper end portion121of the lower storage section120in the plane. The neck portion132amay be curved to be convex toward the central axis.

The crushing member200crushes the bridge BR formed in the tank body100. In this embodiment, an agitator is used as the crushing member200. The agitator has a rotating shaft202, an upper agitator210, and a lower agitator220.

The rotating shaft202is fixed to the tank body100to extend along the central axis. The rotating shaft202can rotate about the central axis relative to the tank body100. The rotating shaft202is shaped to extend from the upper end of the upper storage section110to the lower part of the lower storage section120.

The upper agitator210is connected to a portion of the rotating shaft202located in the upper storage section110. The upper agitator210agitates the wet particles WP in the upper storage section110.

The lower agitator220is connected to a portion of the rotating shaft202located in the lower storage section120. The lower agitator220agitates the wet particles WP in the lower storage section120.

As described above, in the wet particle storage tank1of this embodiment, the bridge forming section130is provided between the upper storage section110and the lower storage section120; therefore, the wet particles WP stored in the upper storage section110and the wet particles WP stored in the lower storage section120are separated in the vertical direction. Thus, the weight of the whole wet particles WP in the tank body100is restrained from acting on the wet particles WP stored at or near the bottom of the lower storage section120, and seepage of the solvent from the wet particles WP is curbed.

In this embodiment, the neck portion132amay be formed with an inclined surface such that the diameter of the neck portion132agradually decreases downward, as shown inFIG.2.

As shown inFIG.3, the connecting section132of the bridge forming section130may be formed in a cylindrical shape having the same diameter as the upper storage section110and the lower storage section120. In this example, the surface roughness of the inner surface (the region indicated by thick lines inFIG.3) of the connecting section132is smaller than the surface roughness of the inner surface of the upper storage section110.

In this example, since the surface roughness of the inner surface of the connecting section132is smaller than the surface roughness of the inner surface of the upper storage section110, the contact area between the wet particles WP and the connecting section132is larger than the contact area between the wet particles WP and the inner surface of the upper storage section110. As a result, the friction between the wet particles WP and the inner surface of the connecting section132is increased, so that the bridge BR is effectively formed in the connecting section132.

As shown inFIG.4, the bridge forming section130may have the connecting section132, and a solvent supply unit134that supplies the solvent toward the inner surface of the connecting section132. The solvent supply unit134sprays the solvent toward the inner surface of the connecting section132while rotating about the central axis relative to the tank body100.

While the agitator is illustrated as an example of the crushing member200in the above embodiment, the crushing member200may be in the form of an air supply unit capable of blowing air against the bridge BR in the tank body100, or an energy applying unit (e.g., a knocker) that applies impact energy from outside the tank body100to the bridge forming section130and its vicinity in the tank body100.

The exemplary embodiment and modified examples described above are specific examples of the following forms.

The wet particle storage tank of the above embodiment includes the tank body capable of storing wet particles containing particles and solvent, and the tank body includes the upper storage section having the supply port through which the wet particles are supplied, the lower storage section located below the upper storage section and having the discharge port through which the wet particles are discharged, and the bridge forming section provided between the upper storage section and the lower storage section. The bridge forming section causes the wet particles to form a bridge to block falling of the wet particles from the upper storage section to the lower storage section.

In the wet particle storage tank, the bridge forming section is provided between the upper storage section and the lower storage section; therefore, the wet particles stored in the upper storage section and the wet particles stored in the lower storage section are separated in the vertical direction. As a result, the weight of the whole wet particles in the tank body is restrained from acting on the wet particles stored at or near the bottom of the lower storage section, and seepage of the solvent from the wet particles is curbed.

The upper storage section and the lower storage section may be formed in a cylindrical shape having the central axis extending in the direction connecting the upper storage section and the lower storage section. In this case, the bridge forming section may have a neck portion. The cross-sectional area of the neck portion in the plane perpendicular to the central axis is smaller than the cross-sectional area of the lower end portion of the upper storage section in the plane perpendicular to the central axis, and is also smaller than the cross-sectional area of the upper end portion of the lower storage section in the plane.

In this form, since the neck portion is formed between the upper storage section and the lower storage section, the wet particles stored in the upper storage section and the wet particles stored in the lower storage section are effectively separated in the vertical direction.

In this case, the neck portion is preferably curved to be convex toward the central axis.

With this arrangement, the wet particles are less likely or unlikely to get caught or stuck on the neck portion.

The bridge forming section may have a connecting portion that connects the upper storage section and the lower storage section. In this case, the surface roughness of the inner surface of the connecting portion is smaller than the surface roughness of the inner surface of the upper storage section.

In this form, the surface roughness of the inner surface of the connecting portion is smaller than the surface roughness of the inner surface of the upper storage section; therefore, the contact area between the wet particles and the connecting portion is larger than the contact area between the wet particles and the inner surface of the upper storage section. Thus, the friction between the wet particles and the inner surface of the connecting portion is increased, so that the bridge is effectively formed in the connecting portion.

The bridge forming section may have the connecting portion that connects the upper storage section and the lower storage section, and a solvent supply unit that supplies the solvent toward the inner surface of the connecting portion.

In this form, the proportion of the solvent in the wet power is increased in the connecting portion, so that the bridge is effectively formed in the connecting portion.

It is preferable that the wet particle storage tank further includes a crushing member that breaks down the bridge formed in the tank body.

In this form, the crushing member can crush the bridge, thus making it easy to cause the wet particles to fall from the upper storage section to the lower storage section.

For example, the crushing member includes an agitator capable of agitating the wet particles in the tank body. The agitator preferably has an upper agitator that agitates the wet particles in the upper storage section, and a lower agitator that agitates the wet particles in the lower storage section.

In this form, it is possible to achieve both the breakage of the bridge by the upper agitator, and the facilitation of discharge of the wet particles from the discharge port by the lower agitator.

Referring next toFIG.5toFIG.8, the evaluation results of the wet particles in both an example of the embodiment and a comparative example will be described. The wet particles containing an active material, conductive particles, resin, and solvent was used.

FIG.5schematically shows a wet particle storage tank used in the example.FIG.6schematically shows a wet particle storage tank used in the comparative example.

As shown inFIG.5, in the example, a tank body100having a neck portion132aformed with an inclined surface and a diameter that gradually decreases downward, as in the example shown inFIG.2, was used.

As shown inFIG.6, in the comparative example, a tank body100B formed in a cylindrical shape with a bottom was used. An agitator200B is provided in the tank body100B.

FIG.7schematically shows a device for evaluating the spreadability of the wet particles WP. As shown inFIG.7, the device has an upper plate11, a lower plate12located below the upper plate11, and a middle plate13located between the upper plate11and the lower plate12to contact with the upper surface of the lower plate12.

The spreadability of the wet particles WP was evaluated in the following manner. Specifically, the middle plate13was inserted between the upper plate11and the lower plate12, as indicated by the arrow inFIG.7, so that the spreadability was evaluated based on the distance h between the upper plate11and the middle plate13when a specified shear load was generated by the wet particles WP sandwiched between the middle plate13and the upper plate11. In this connection, the upper surface of the lower plate12and the lower surface of the middle plate13that is in contact with this upper surface are inclined such that the distance between the upper plate11and the middle plate13is reduced as the middle plate13is inserted.

Various evaluations including the spreadability were conducted on the wet particles WP stored in a bottom part A of the tank body100of the example, and the wet particles WP stored in a bottom part B of the tank body100B of the comparative example.FIG.8shows the evaluation results.

As shown inFIG.8, the wet particles WP stored in the bottom part A of the example were free from seepage of the solvent, and had good spreadability (there was no alteration). When the wet particles WP were formed into films by the MPS (Moving Particle Semi-Implicit) film formation method, no defect was observed in the films thus formed.

On the other hand, the wet particles WP stored in the bottom part B of the comparative example suffered seepage of the solvent, and had poor spreadability (alteration occurred). When the wet particles WP were formed into films by the MPS film formation method, defects were observed in the films thus formed.

It is to be understood that the embodiments and examples disclosed herein are exemplary in all respects, and are not restrictive. The scope of the disclosure is defined by the claims rather than the description of the above embodiments and examples, and further includes all changes within the meaning and scope equivalent to the claims.