JP7277662B1 - Sagger, sagger set and manufacturing method of sagger - Google Patents

Abstract

A technique for making a sagger less likely to be damaged during heat treatment is provided. The sagger is a sagger that is placed in a heat treatment furnace in a state in which powder of a lithium positive electrode material is accommodated for heat treatment of the powder. The sagger is made of a nickel-based alloy. When the sagger is viewed from above, the size of the upper end of the sagger is equal to or smaller than the size of the bottom of the sagger. [Selection drawing] Fig. 1

Description

TECHNICAL FIELD The technology disclosed in this specification relates to a sagger used when heat-treating powder of a lithium positive electrode material.

A heat treatment furnace (for example, a roller hearth kiln, etc.) may be used to heat-treat the powder that is the raw material for the lithium positive electrode material. When the powder of the lithium positive electrode material (hereinafter also simply referred to as powder) is heat-treated in the heat treatment furnace, the powder is stored in a sagger, and the sagger containing the powder is transported in the heat treatment furnace. . Since the temperature for heat-treating the powder of the lithium positive electrode material is high, the powder is generally housed in a sagger made of ceramic having high heat resistance. However, in recent years, a technique for heat-treating powder using a metal sagger has been developed. Compared to ceramic saggers, metal saggers are less likely to break. For example, Patent Literature 1 discloses an example of technology for manufacturing a sagger using a nickel-based alloy. Patent Literature 1 discloses a nickel-based alloy excellent in corrosion resistance and mechanical strength at high temperatures, and discloses manufacturing a sagger using this nickel-based alloy.

International Publication No. 2021/132350

The sagger using the nickel-based alloy of Patent Document 1 is manufactured using a manufacturing method such as forging or casting. When a metal sagger is manufactured using a manufacturing method such as forging or casting, when the sagger is viewed from above, the size of the upper end of the sagger is larger than the size of the bottom of the sagger in order to release it from the mold. The height tends to be larger. Since the sagger has a box shape with an open top, the strength of the top is lower than that of the bottom. On the other hand, when heat-treating the powder contained in the saggers, the plurality of saggers are transported in the heat treatment furnace while being aligned in the transport direction and in the direction perpendicular to the transport direction. If the sagger meanders while being conveyed in the heat treatment furnace, it will come into contact with the adjacent sagger. If the upper end of the sagger is larger than the bottom surface of the sagger, the upper ends of the saggers may come into contact with each other when contacting adjacent saggers, resulting in damage to the saggers.

This specification discloses a technique that makes the sagger less likely to break during heat treatment.

A sagger according to a first aspect of the technology disclosed in this specification is a sagger that is placed in a heat treatment furnace in a state in which powder of a lithium positive electrode material is accommodated and heat-treats the powder. The sagger is made of a nickel-based alloy. When the sagger is viewed from above, the size of the upper end of the sagger is equal to or smaller than the size of the bottom of the sagger.

In the above-described saggers, when contacting adjacent saggers during transportation in the heat treatment furnace, the large bottoms of the saggers tend to come into contact with each other. Since the sagger is box-shaped, the bottom is stronger than the top. Therefore, the sagger is less likely to be damaged during the heat treatment.

Further, the method for manufacturing a sagger according to the first aspect of the technology disclosed in this specification includes a rectangular bottom surface and four side surfaces connected to each side of the bottom surface, and a space surrounded by the bottom surface and the four side surfaces. A method for manufacturing a sagger which is capable of containing powder of a lithium positive electrode material in a space and which is placed in a heat treatment furnace for heat-treating the powder contained in the space. The manufacturing method includes a cutting step of cutting a metal piece including a bottom surface and four side surfaces from a nickel-based alloy flat plate, and a welding step of forming the shape of a sagger by welding the metal pieces cut in the cutting step. And prepare. In the cutting step, the metal piece is cut so that the size of the upper end of the sagger is equal to or less than the size of the bottom of the sagger when the sagger is viewed from above.

In the method for manufacturing the sagger, metal pieces cut so that the size of the upper end of the sagger is equal to or smaller than the size of the bottom of the sagger are formed into the shape of the sagger by welding. This makes the top of the sagger smaller than the bottom. Since the upper end portion of the sagger is smaller than the bottom surface, the upper end portion of the sagger is less likely to come into contact with adjacent saggers during transportation in the heat treatment furnace, and the sagger is less likely to be damaged.

The perspective view which shows the sagger which concerns on Example 1, 2. FIG. The sagger of the modification 1 is shown, (a) is a side view, (b) is a top view. The perspective view which shows the sagger of the modification 2. FIG. The sagger of the modified example 2 is shown, (a) is a side view, (b) is a top view. The side view which shows the state which arranged the sagger of the modification 2 on the conveyance surface. The perspective view which shows a connection jig. The top view which shows the connection jig|tool which connects several saggers which were put in order on the conveyance surface, and the saggers. 4 is a flow chart showing an example of a method for manufacturing a sagger according to Example 1. FIG. The figure which shows one metal piece in the state which expanded the sagger. 6 is a flow chart showing an example of a method for manufacturing a sagger according to Example 2. FIG. A diagram showing five metal pieces that form each side of the sagger (bottom and four sides).

The main features of the embodiments described below are listed. It should be noted that the technical elements described below are independent technical elements, and exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims as of the filing. do not have.

In the sagger of the second aspect of the technology disclosed herein, in the sagger of the first aspect, when the sagger is viewed from above, the outer peripheral shape of the upper end of the sagger is It may be located inside the outer peripheral shape of the bottom. According to such a configuration, when contacting adjacent saggers during transportation in the heat treatment furnace, the bottoms are likely to come into contact with each other. For this reason, the upper end portion is less likely to come into contact with the adjacent sagger, and the sagger is less likely to be damaged.

In the sagger of the third aspect of the technology disclosed in this specification, in the sagger of the first or second aspect, the sagger has a rectangular bottom surface and four side surfaces connected to each side of the bottom surface. may be provided. Joints may be provided at least between the side surfaces to join the adjacent side surfaces by welding. According to such a configuration, by joining at least the side surfaces by welding, the upper end portion of the sagger can be easily made smaller than the bottom surface.

In the sagger of the fourth aspect of the technology disclosed herein, in any one of the saggers of the first to third aspects, the nickel-based alloy may contain aluminum. The content of aluminum in the nickel-based alloy may be 2 wt % or more and 5 wt % or less. According to such a configuration, since the nickel-based alloy contains aluminum, when the sagger is placed under heat treatment conditions (for example, when placed in a heat treatment furnace), the alumina coating is applied to the surface of the sagger. is formed. As a result, the strength of the sagger can be improved, and the oxidation of the sagger due to the powder in the sagger during the heat treatment can be suppressed.

In the sagger of the fifth aspect of the technology disclosed in this specification, in any one of the saggers of the first to fourth aspects, the sagger has a rectangular bottom surface and on each side of the bottom surface It may have four sides that connect. The sagger may further comprise first projections located on at least two of the four sides. The first protrusion may be installed on the outer surface of the side surface and protrude from the upper end of the side surface. According to such a configuration, by installing the first projections on at least two of the side surfaces, when the saggers are vertically stacked, it is possible to suppress the displacement of the vertically stacked saggers.

In the sagger of the sixth aspect of the technology disclosed in this specification, in any one of the saggers of the first to fifth aspects, the sagger has a rectangular bottom surface and a It may have four sides that connect. The four sides may include a first side and a second side. The sagger may further comprise a second protrusion located on the first side surface and a third protrusion located on the second side surface. The second protrusion may be located on the outer surface between the lower end and the upper end of the first side. A third protrusion may be installed on the outer surface between the lower end and the upper end of the second side. The lower end of the third projection may be positioned higher than the upper end of the second projection. According to such a configuration, by providing the second projection and the third projection, when the saggers are conveyed side by side in the heat treatment furnace and the sagger contacts another adjacent sagger, the second projection It becomes easy for the sagger and the 3rd projection to contact the adjoining sagger, and it becomes difficult for the sagger bodies (bottom and side surfaces) to contact each other. For this reason, the sagger body (bottom and side surfaces) is less likely to be damaged. Further, since the lower end of the third projection is positioned higher than the upper end of the second projection, the second projection and the third projection are positioned at different heights. For this reason, when the first side surface on which the second projection of one sagger is provided and the second side surface on which the third projection of another sagger is provided are arranged to face each other, the second projection of the one sagger and the third projections of the other saggers are vertically displaced and do not contact each other. Contact between the second projection of one sagger and the third projection of another sagger causes meandering or rotation of the first sagger or other saggers. The second projection of one sagger and the third projection of the other sagger are vertically offset to avoid direct contact between adjacent sagger bodies (bottom and side surfaces) while avoiding direct contact. Meandering of the sagger can be avoided by the second projection and the third projection.

In addition, the sagger set disclosed in the present specification includes any one of the saggers of the first to fifth aspects described above and a plurality of saggers when the plurality of saggers are arranged on a plane and a connecting jig for connecting the The connecting jig may be made of a nickel-based alloy. The connecting jig may have a plate-like upper surface and a plurality of protrusions installed below the upper surface. The upper surface may be arranged across the upper ends of a plurality of saggers arranged on a plane. At least one of the plurality of protrusions is arranged inside the side surface of one of the plurality of saggers arranged on the plane, and at least one other of the plurality of protrusions. One may be arranged inside the side surface of another of the plurality of saggers arranged on a plane. According to such a configuration, by providing the connection portion for connecting the plurality of saggers, the plurality of saggers can be conveyed in the heat treatment furnace while being connected. Therefore, it is possible to prevent a plurality of saggers from being separated and meandering. Moreover, since the connecting jig is made of a nickel-based alloy, it is possible to suppress breakage of the connecting jig during the heat treatment.

Further, in the method for manufacturing a sagger according to the second aspect of the technique disclosed in this specification, in the method for manufacturing a sagger according to the first aspect, in the cutting step, between each side of the bottom surface and each side surface You may cut one piece of metal in the deployed state with the . The manufacturing method may further comprise a folding step of folding one piece of metal cut in the cutting step between each side of the bottom surface and each side surface. In the welding step, the sides included in one piece of metal bent in the bending step may be welded. According to such a method, it is possible to suitably manufacture a sagger in which the size of the upper end is equal to or less than the size of the bottom surface.

In the method for manufacturing a sagger according to the third aspect of the technology disclosed in the present specification, in the method for manufacturing a sagger according to the first aspect, in the cutting step, the bottom surface and the four side surfaces are separated into individual metal pieces. It can be cut as In the welding process, welding may be performed between each side of the bottom surface and each side surface and between each side surface. Also by such a method, it is possible to suitably manufacture a sagger in which the size of the upper end is equal to or smaller than the size of the bottom surface.

In the sagger manufacturing method of the fourth aspect of the technology disclosed herein, in any one of the sagger manufacturing methods of the first to third aspects, the welding step includes welding by TIG welding. You may

In the sagger manufacturing method of the fifth aspect of the technology disclosed herein, in any one of the sagger manufacturing methods of the first to fourth aspects, the nickel-based alloy contains aluminum You may have The content of aluminum in the nickel-based alloy may be 2 wt % or more and 5 wt % or less. The manufacturing method may further include a heat treatment step of heat-treating the sagger welded in the welding step in an oxygen atmosphere at an ambient temperature of 750-1000° C. for 5-10 hours. According to such a configuration, internal stress can be relaxed by the heat treatment process. Further, since the nickel-based alloy contains aluminum, a dense alumina coating can be formed on the surface of the sagger by heat-treating under the above conditions. Therefore, it is possible to suppress precipitation of the components of the sagger from the inside of the sagger due to the powder contained in the sagger during the heat treatment.

(Example 1)
The sagger 10 will be described with reference to the drawings. The sagger 10 accommodates an object to be processed which is powder. In the present embodiment, the object to be treated contained in the sagger 10 is powder of lithium positive electrode material (hereinafter also simply referred to as "powder"). A heat treatment furnace (for example, a roller hearth kiln or the like) for heat-treating powder is configured to convey the sagger 10 from the inlet to the outlet. The sagger 10 containing the powder is conveyed through the heat treatment furnace.

As shown in FIG. 1, the sagger 10 has a substantially rectangular parallelepiped box shape and includes a bottom surface 12 and four side surfaces 14a to 14d. The sagger 10 (ie, bottom 12, four sides 14a-14d) is metallic and formed of a nickel-based alloy. The nickel-based alloy of this embodiment contains 2 wt % or more and 5 wt % or less of aluminum.

The bottom surface 12 is rectangular, and side surfaces 14a to 14d are connected to each of four sides. The side surfaces 14a to 14d are substantially rectangular and connected to the bottom surface 12 substantially perpendicularly. The ends of adjacent side surfaces 14a-14d are joined by welding. That is, joints 16 formed by welding are provided between the ends of adjacent side surfaces 14a to 14d. No joint 16 is provided between the side surfaces 14a-14d and the bottom surface 12, and the side surfaces 14a-14d are formed by bending a piece of metal, as will be described later. Note that in FIG. 1, the four side surfaces 14a to 14d are shown separately from the side surfaces 14a, 14b, 14c, and 14d in the circumferential direction. Hereinafter, when it is necessary to distinguish other constituent elements, they are described using alphabetical subscripts. may be described.

When the sagger 10 is viewed from above, the size of the upper end is smaller than the size of the bottom surface 12, and in this embodiment, the size of the upper end substantially matches the size of the bottom surface 12. - 特許庁That is, when the sagger 10 is viewed from above, the outer peripheral shape of the upper end of the four side surfaces 14 a to 14 d and the outer peripheral shape of the bottom surface 12 are substantially the same, and the outer peripheral shape of the four side surfaces 14 a to 14 d is the same as that of the bottom surface 12. It is not located outside the outer peripheral shape.

The size of the upper ends of the four side surfaces 14a to 14d of the sagger 10 may be equal to or smaller than the size of the bottom surface 12. For example, as shown in FIG. may be smaller in size than the bottom surface 112 . That is, when the sagger 110 is viewed from above, the outer peripheral shape of the upper ends of the four side surfaces 114 may be smaller than the outer peripheral shape of the bottom surface 112 and positioned inside the outer peripheral shape of the bottom surface 112 . For example, in this embodiment, one side of the bottom surface 12 of the sagger 10 is 300 mm, and the dimension L1 of the upper side of the side surface 114 is smaller than the dimension L2 of the lower side of the side surface 114 by 0 to 2 mm.

In this embodiment, the size of the upper end of the sagger 10 is equal to or smaller than the size of the bottom surface 12, and when the sagger 10 is viewed from above, the outer peripheral shape of the four side surfaces 14a to 14d is the same as that of the bottom surface 12. not located outside the outer peripheral shape of The sagger 10 is conveyed through the heat treatment furnace with the powder contained therein. The saggers 10 may meander while being conveyed in the heat treatment furnace, and adjacent saggers 10 may come into contact with each other in the heat treatment furnace. In this embodiment, since the size of the upper end portion of the sagger 10 is equal to or smaller than the size of the bottom surface 12, when the adjacent saggers 10 come into contact with each other, they are located outside when viewed from above. The bottom surfaces 12 are in contact with each other, and the upper ends are less likely to be in contact. The sagger 10 is box-shaped and has an open top. Therefore, the strength of the upper end portion is lower than that of the bottom surface 12 . When the adjacent saggers 10 come into contact with each other, the saggers 10 can be prevented from being damaged in the heat treatment furnace by the contact of the bottom surfaces 12 with high strength.

Moreover, in this embodiment, the sagger 10 is made of a nickel-based alloy. For example, the sagger may be formed of ceramic. Since the sagger 10 is made of metal, its strength is higher than that of a ceramic sagger, and the sagger 10 is less likely to be damaged even if an impact is applied to the sagger 10 when it is conveyed in the heat treatment furnace. Further, by forming the sagger 10 from a nickel-based alloy, the sagger 10 is less likely to be corroded, and even if it is corroded, cracks are less likely to occur during reaction expansion. Furthermore, since the nickel-based alloy has high strength, the sagger 10 can be made larger than a ceramic sagger and can be made thinner than a ceramic sagger. Therefore, the amount of powder that can be contained in the sagger 10 can be increased. In this embodiment, the plate thickness of the bottom surface 12 and the side surface 14 is 2-5 mm. A plate thickness of 2 to 5 mm facilitates welding when manufacturing the sagger 10 . Further, by setting the plate thickness to 5 mm or less, it is possible to avoid an increase in cost.

Table 1 below shows a comparison of the physical properties of mullite (an example of a ceramic) and nickel-based alloys. As shown in Table 1 below, since the nickel-based alloy has a smaller heat capacity than mullite, the sagger 10 can reduce the thermal energy required for heating in the heat treatment furnace. In addition, since the nickel-based alloy has a higher thermal conductivity than mullite, the sagger 10 can heat the powder contained therein in a short period of time.

Nickel-based alloys can also be separated by melting the nickel. For this reason, the ceramic sagger is discarded when it becomes unusable due to cracks or the like, while the nickel-based alloy sagger 10 of the present embodiment can be recycled after it becomes unusable. can.

Moreover, as shown in FIGS. 3 and 4 , a plurality of projections 20 , 22 , 24 may be installed on the side surface 14 of the sagger 210 of the second modification. The sagger 210 includes a sagger body 211 and a plurality of projections 20, 22, 24. The sagger body 211 has the same shape as the sagger 10 in FIG. Therefore, description of the sagger body 211 is omitted.

In the sagger 210 of Modification 2, a plurality of projections 20, 22, 24 are installed on the side surfaces 14a to 14d of the sagger body 211. As shown in FIG. The plurality of projections 20, 22, 24 are made of a nickel-based alloy containing 2 wt % or more and 5 wt % or less of aluminum, like the sagger body 211 (that is, the sagger 10 of FIG. 1). A plurality of saggers 210 can be vertically stacked (stacked) and transported in the heat treatment furnace, and can also be transported in the heat treatment furnace by arranging them on a conveying surface (flat surface). The plurality of protrusions 20, 22, and 24 cause the vertically stacked saggers 210 to shift or the saggers 210 arranged on the transport surface to come into contact with each other while the saggers 210 are being transported in the heat treatment furnace. It is installed to prevent The projection 20 projects upward from the sagger 210 , and the projections 22 and 24 project laterally from the sagger 210 . Hereinafter, the protrusion 20 will be referred to as the "upper protrusion 20" and the protrusions 22, 24 will be referred to as the "side protrusions 22, 24".

First, the upper protrusion 20 will be described. An upper projection 20 is attached to the outer surface of side 14 . Upper protrusions 20 are located on two or more of the four sides 14a-14d. In this embodiment, two upper protrusions 20a, 20b are provided, upper protrusion 20a being placed on side 14a and upper protrusion 20b being placed on side 14b adjacent to side 14a. The upper projection 20a has a plate shape and is arranged parallel to the side surface 14a on which it is installed. The upper projection 20a has a dimension along the outer surface of the side surface 14a (the X direction in FIG. 3) smaller than the dimension of the side surface 14a in the same direction. Moreover, the dimension in the height direction (the Z direction in FIG. 3) of the upper protrusion 20a is also smaller than the dimension in the height direction of the side surface 14a. The upper end of the upper projection 20a is located above the upper end of the side surface 14a. The upper protrusion 20b has the same shape as the upper protrusion 20a, and the upper end of the upper protrusion 20b is located above the upper end of the side surface 14b. In addition, in the sagger 110 shown in FIG. 2, the size of the upper ends of the four side surfaces 114 of the sagger 110 is smaller than the size of the bottom surface 112 . Even in such a case, as shown in FIG. 3, by providing upper protrusions on two adjacent side surfaces, the saggers 110 can be stacked vertically.

By installing a plurality of upper protrusions 20 (upper protrusions 20a and 20b in this embodiment) on the side surface 14, it is possible to prevent the stacked saggers 210 from shifting. Vibration may be applied to the sagger 210 when the sagger 210 is conveyed through the heat treatment furnace. Even if vibration is applied to the stacked saggers 210, the upper projection 20 serves as a stopper to suppress the displacement of the saggers 210 positioned above relative to the saggers 210 positioned below.

In this embodiment, the sagger 210 is provided with the two upper projections 20a and 20b, but the configuration is not limited to this. For example, the sagger 210 may be provided with three or more upper protrusions 20 . Specifically, the upper projection 20 may be installed not only on the side surfaces 14a and 14b but also on one of the side surfaces 14c and 14d, or on both of the side surfaces 14c and 14d (that is, on the four side surfaces 14a to 14d). 14d) may be provided with an upper protrusion 20 . Also, a plurality of upper projections 20 may be installed on one side surface 14 . However, when the size of the upper end of the four sides of the sagger is smaller than the size of the bottom (for example, in the case of the sagger 110 shown in FIG. 2), the outer surfaces of the two opposite sides of the sagger are With the top projection, such saggers cannot be stacked vertically. Therefore, the plurality of upper protrusions 20 are installed so as to be positioned outside the outer peripheral shape of the bottom surface 12 when viewed from above. That is, the shape of the upper projection 20 is changed so that the upper projection is located at a position shifted outward from the outer surface of the side surface of the sagger,

Next, the lateral projections 22, 24 will be described. Lateral projections 22 , 24 are attached to the outer surface of side 14 . The side projections 22 and 24 are plate-shaped and are installed parallel to the bottom surface 12 . The dimension of the side projections 22, 24 along the outer surface of the side surface 14 (for example, the X direction in FIG. 3 for the side surface 14a) is smaller than the dimension of the side surface 14 in the same direction. The dimensions of the plurality of lateral projections 22 and 24 in the direction extending from the side surface 14 (the direction perpendicular to the side surface 14) are substantially the same.

The lateral projections 22 are installed at different heights than the lateral projections 24 . Below, the side projection 22 may be called "the 1st side projection 22", and the side projection 24 may be called "the 2nd side projection 24." Specifically, the lower end of the second lateral projection 24 is positioned higher than the upper end of the first lateral projection 22 .

Of the four side surfaces 14, two adjacent side surfaces 14 (side surfaces 14a and 14b in this embodiment) are provided with first lateral projections 22, and the other two adjacent side surfaces 14 (in this embodiment In the example, the side surfaces 14c, 14d) are provided with second lateral projections 24 . That is, opposite side surfaces 14 are provided with different types of lateral projections 22,24. For example, a first side projection 22 is installed on the side surface 14a, and a second side projection 24 is installed on the side surface 14c facing the side surface 14a. Similarly, a first side projection 22 is installed on the side surface 14b, and a second side projection 24 is installed on the side surface 14d facing the side surface 14b.

Each side surface 14 is provided with two lateral projections 22, 24 of the same kind. In this embodiment, two first side protrusions 22 are provided on each of the side surfaces 14a and 14b, and two second side protrusions 24 are provided on each of the side surfaces 14c and 14d. Two lateral projections 22 and 24 installed on one side surface 14 are spaced apart in a direction parallel to the long side of the side surface 14 . In this embodiment, each side surface 14 is provided with two side projections 22 and 24, but each side surface 14 may be provided with one side projection or a side projection. may be installed at the same height.

By installing the first lateral projections 22 and the second lateral projections 24, the first lateral projections 22 and/or the second lateral projections 22 and/or the second lateral projections 22 and/or the first lateral projections 22 and/or the second lateral projections 210, when adjacent saggers 210 are in contact while being transported through the heat treatment furnace. The two lateral projections 24 contact the side surfaces 14 of adjacent saggers 210 to avoid contact between the side surfaces 14 of adjacent saggers 210 . The position where the first lateral projection 22 or the second lateral projection 24 contacts is not the upper end of the side surface 14 but the intermediate portion between the upper end and the lower end. Since the intermediate portion of the side surface 14 has higher mechanical strength than the upper end portion of the side surface, damage to the sagger 210 can be suppressed. In addition, by providing the first lateral projections 22 and the second lateral projections 24 as described above, different types of lateral projections 22 and 24 are positioned on the opposing side surfaces 14 of adjacent saggers 210. , a plurality of saggers 210 can be arranged on the conveying surface. That is, the side surface 14 on which the first lateral protrusion 22 is installed faces the side surface 14 on which the second lateral protrusion 24 of the other sagger 210 is installed, and the side surface 14 on which the second lateral protrusion 24 is installed. , two adjacent saggers 210 can be placed side by side such that the side surfaces 14 of the other sagger 210 on which the first lateral projections 22 are installed face each other. For example, a first side projection 22 is installed on the side surface 14b, and a second side projection 24 is installed on the side surface 14d facing the side surface 14b. As shown in FIG. 5, when the two saggers 10a and 10b are arranged on the conveying surface in the X direction, the side surface 14b of the sagger 210a faces the side surface 14d of the adjacent sagger 210b. A first side projection 22 is installed on the side surface 14b of the sagger 210a, and a second side projection 24 is installed on the side surface 14d of the adjacent sagger 210b. Since the first lateral projection 22 and the second lateral projection 24 are installed at different heights, the first lateral projection 22 installed on the side surface 14b of the sagger 210a and the side surface 14d of the adjacent sagger 210b The second lateral projections 24 installed in the are not in contact. When the same type of lateral protrusions 22 or 24 are installed on the opposing side surfaces 14 of adjacent saggers 210, the same type of lateral protrusions 22 or 24 have the same height, so the adjacent saggers 210 contacts the lateral projections 22 or 24 located in the . If the side projections 22 and 24 of the same type come into contact with each other, the sagger 210 may rotate and meander. Adjacent saggers 210 can avoid meandering of the saggers 210 due to the side projections 22 , 24 by facing different types of side projections 22 , 24 .

Also, by providing the first side projection 22 and the second side projection 24, the sides 14 of the saggers 210 do not come into contact with each other, so a gap is created between the saggers 210.例文帳に追加By forming a gap between the saggers 210, the atmosphere gas can pass through the gaps between the saggers 210, the atmosphere gas can be easily supplied into the sagger 210, and the reaction gas generated from the powder by the heat treatment can be scavenged. It can be done easily.

In this embodiment, the lateral projections 22 or 24 are installed on all the side surfaces 14, but the configuration is not limited to this. For example, two adjacent sides 14 (e.g., side 14a and side 14b) may be provided with lateral protrusions 22 or 24, and two other sides 14 (e.g., side 14c and side 14d) may be provided with lateral protrusions 22 or 24. 24 may not be installed. In this case as well, in the adjacent saggers 210, the side surfaces 14 on which the side projections 22 or 24 are not installed are prevented from facing each other, and the side surfaces 14 of the two adjacent saggers 210 are prevented from coming into contact with each other. can be avoided.

Further, as shown in FIGS. 6 and 7, when a plurality of saggers 10, 110, 210 are arranged on the conveying surface and conveyed in the heat treatment furnace, a connecting jig 30 is used to connect the plurality of saggers 10, 110. , 210 can be transported in a connected state.

As shown in FIG. 6 , the connecting jig 30 has an upper plate 32 and a projecting portion 34 . The upper plate 32 is substantially rectangular and has four projecting portions 34 connected to its lower surface. The protrusions 34 are bar-shaped, and the four protrusions 34 connected to the top plate 32 have the same shape. The connecting jig 30 (that is, the upper plate 32 and the four protrusions 34) is also made of a nickel-based alloy.

FIG. 7 shows a state in which a plurality of saggers 10 arranged on the conveying surface are connected by a connecting jig 30. As shown in FIG. 7, the upper projection 20 and the sagger 10 (see FIG. 1) that does not have the side projections 22, 24 are connected by the connecting jig 30, but the upper projection 20, the side projections 22, A sagger 210 (see FIGS. 3 and 4) having 24 can also be connected with the connecting jig of this embodiment. In this case, in a plurality of saggers 210 connected by a connecting jig, gaps are created between the side surfaces 14 of adjacent saggers 210 by the side projections 22 and 24 (not shown).

The connecting jig 30 is arranged across the upper surfaces of the four saggers 10 arranged on a plane. At this time, the connecting jig 30 is arranged such that the four projecting portions 34 are located in different saggers 10, respectively. For example, in FIG. 7, the sagger 10b is arranged on the +X direction side of the sagger 10a, the sagger 10d is arranged on the -Y direction side of the sagger 10a, and the sagger 10e is arranged on the -Y direction side of the sagger 10b. are placed. In this case, the connecting jig 30 (that is, the connecting jig 30 on the left side in FIG. 7) is arranged so as to straddle the corners of the saggers 10a, 10b, 10d, and 10e. In addition, the projecting portion 34 located at the corner of the sagger 10a (the upper left projecting portion 34 in FIG. 7) is located inside the sagger 10a and the projecting portion 34 located at the corner of the sagger 10b (FIG. 7 Then, the upper right protrusion 34) is located in the sagger 10b, and the protrusion 34 located at the corner of the sagger 10d (in FIG. 7, the lower left protrusion 34) is located in the sagger 10d. , the protrusion 34 located at the corner of the sagger 10e (lower right protrusion 34 in FIG. 7) is located inside the sagger 10e. A plurality of saggers 10 can be connected by positioning a plurality of protrusions 34 in different saggers 10 . Thereby, when the saggers 10 are conveyed in the heat treatment furnace, the plurality of connected saggers 10 are suppressed from meandering apart, and the adjacent saggers 10 can be prevented from colliding with each other. .

Moreover, the connecting jig 30 is made of a nickel-based alloy. For example, if the connecting jig 30 is made of ceramic, its strength is lower than that of the nickel-based alloy forming the sagger 10, and there is a risk of breakage due to thermal shock during heat treatment of the powder or impact during transportation. Since the connecting jig 30 is made of a nickel-based alloy, it is possible to prevent the connecting jig 30 from being damaged while the sagger 10 is being conveyed through the heat treatment furnace.

Next, a method for manufacturing the sagger 10 will be described with reference to FIGS. 8 and 9. FIG. A method of manufacturing a sagger 10 (see FIG. 1) that does not have an upper projection 20 and side projections 22, 24 will now be described. When manufacturing the sagger 210 (see FIGS. 3 and 4) having the upper projection 20 and the side projections 22 and 24, the sagger 10 (that is, the sagger body 211) was manufactured by the following method. Later, the upper projection 20 and side projections 22, 24 may be attached by welding.

As shown in FIG. 8, first, a cutting step is performed to cut one metal piece 40 including a portion corresponding to the bottom surface 12 and portions corresponding to four side surfaces 14 from a nickel-based alloy flat plate (S12). The metal piece 40 is one metal piece with the sagger 10 unfolded, and is a metal piece with the side surfaces 14 connected to the sides of the bottom surface 12 (see FIG. 9). As shown in FIG. 2, when the size of the upper ends of the four side surfaces 114 of the sagger 110 is smaller than the size of the bottom surface 112, the length of the long side on the upper end side of the side surfaces 114 is equal to the bottom surface of the side surface. Shorter than the length of the long side of the side. That is, by making the shape of the side surface 114 trapezoidal, the size of the upper ends of the four side surfaces of the sagger 110 can be made smaller than the size of the bottom surface.

Next, a bending step is performed to bend the metal piece 40 between each side of the bottom surface 12 and each side surface 14 (S14). In the folding step, the portions corresponding to the side surfaces 14 are folded substantially perpendicularly to the portions corresponding to the bottom surface 12 (see FIG. 9).

Next, a welding process is performed to weld adjacent side surfaces 14 (S16). In the welding process, the metal pieces 40 are welded by TIG welding. Nickel-based alloys have poor workability, making them difficult to weld properly in some types of welding. By using TIG welding, metal strips 40 that are nickel-based alloys can be properly welded. A joint 16 (see FIG. 1) is formed between adjacent sides 14 by welding between adjacent sides 14 . The shape of the sagger 10 is formed by the processing of steps S12 to S16.

For example, if the shape of the sagger 10 is formed using a manufacturing method such as forging or casting, the size of the upper end of the sagger 10 tends to be larger than the size of the bottom surface 12 . In this embodiment, a metal piece 40 including portions corresponding to each side (bottom surface 12 and four side surfaces 14) of the sagger 10 is cut from a nickel-based alloy flat plate, and the metal piece 40 is welded to form the sagger 10. is molded into the shape of The metal piece 40 is cut into a desired shape and welded at necessary points to form the sagger 10 so that the size of the upper end of the sagger 10 is equal to or smaller than the size of the bottom surface 12. , the sagger 10 can be accurately molded.

Next, a heat treatment step is performed for heat-treating the metal piece 40 shaped into the shape of the sagger 10 (S18). The metal piece 40 after the heat treatment process is hereinafter referred to as the sagger 10 . In the heat treatment step, the metal piece 40 is heat treated in an oxygen atmosphere at an ambient temperature of 750 to 1000° C. for 5 to 10 hours. When the welding process of step S16 is executed, internal stress is generated in the metal piece 40 . By heat-treating the formed metal piece 40 under the above conditions, the internal stress of the metal piece 40 after welding can be relaxed. Also, the nickel-based alloy forming the metal piece 40 contains aluminum. Therefore, a dense alumina coating is formed on the surface of the metal piece 40 formed into the shape of the sagger 10 by heat-treating under the above conditions (particularly in an oxygen atmosphere). By forming an alumina coating on the surface, it is possible to suppress precipitation of components of the sagger 10 from the inside of the sagger 10 due to the powder while the powder in the sagger 10 is heat-treated in the heat treatment furnace.

(Example 2)
In the above embodiment, one metal piece 40 with the sagger 10 unfolded is cut from the nickel-based alloy flat plate, but the configuration is not limited to this. For example, as shown in FIG. 11, a metal piece 42 in the shape of the bottom surface 12 and a metal piece 44 in the shape of the four side surfaces 14 may be separately cut from a plate of nickel-based alloy. A method of manufacturing the sagger 10 (that is, the sagger 10 without the upper projection 20 and the lateral projections 22, 24) in this embodiment will be described below. Also in the present embodiment, after manufacturing the sagger 10 (that is, the sagger body 211) by the following method, the upper projection 20 and the side projections 20 and the side projections 20 and the side projections 20 and 24 are attached by welding. A sagger 210 having squares 22, 24 can be manufactured.

As shown in FIG. 10, first, a cutting step is performed to cut a metal piece 42 in the shape of the bottom surface 12 and four metal pieces 44 in the shape of the side surfaces 14 from a nickel-based alloy flat plate (S22). That is, in the welding process of this embodiment, five separate metal strips, one metal strip 42 and four metal strips 44, are cut from the nickel-based alloy flat plate. In the present embodiment, each surface (the bottom surface 12 and the four side surfaces 14) constituting the sagger 10 is cut separately, so unlike the first embodiment, the folding step (S14 in FIG. 8) is not performed.

Next, a welding step is performed to weld one metal piece 42 and four metal pieces 44 to form the shape of the sagger 10 (S24). Specifically, a metal piece 44 is vertically arranged on each side of the metal piece 42, and each side of the metal piece 42 and the metal piece 44 are welded. Also, the adjacent metal pieces 44 are welded. Therefore, when the method of this embodiment is used, not only the joint 16 is formed between the side surfaces 14, but also a weld joint (not shown) is formed between the bottom surface 12 and the side surface 14. FIG. Also in the present embodiment, the metal piece 40 is welded by TIG welding in the welding process. The shape of the sagger 10 is formed by the processing in steps S22 and S24.

Next, a heat treatment step is performed for heat-treating the metal pieces 42 and 44 formed into the shape of the sagger 10 (S26). Note that the processing of step S26 is the same as the processing of step S18 in the first embodiment, so detailed description thereof will be omitted. The method of this embodiment also forms the sagger 10 by welding. Therefore, the sagger 10 can be formed accurately so that the size of the upper end portion of the sagger 10 is equal to or smaller than the size of the bottom surface 12 .

Points to note regarding the sagger 10 described in the embodiment will be described. The upper projection 20 of the embodiment is an example of a "first projection", the first lateral projection 22 is an example of a "second projection", and the second lateral projection 24 is an example of a "third projection". It is an example, and the upper plate 32 is an example of the "upper surface".

Although specific examples of the technology disclosed in this specification have been described above in detail, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. In addition, the technical elements described in this specification or in the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the techniques exemplified in this specification or drawings achieve multiple purposes at the same time, and achieving one of them has technical utility in itself.

10, 110: saggers 12, 112: bottom surface 14, 114: side surface 16: joint 20: upper projection 22: first side projection 24: second side projection 30: connecting jig 32: upper plate 34: projection Parts 40, 42, 44: metal pieces

Claims (4)

A sagger having a rectangular bottom surface and four side surfaces connected to each side of the bottom surface, and capable of containing lithium positive electrode material powder in a space surrounded by the bottom surface and the four side surfaces,
A method for manufacturing the sagger placed in a heat treatment furnace for heat-treating the powder contained in the space,
a cutting step of cutting a metal piece including the bottom surface and the four side surfaces from a flat plate of nickel-based alloy;
a welding step of forming the shape of the sagger by welding the metal pieces cut in the cutting step;
with
In the cutting step, when the sagger is viewed from above, the metal piece is cut so that the size of the upper end of the sagger is equal to or smaller than the size of the bottom of the sagger ,
The nickel-based alloy contains aluminum,
The content of aluminum in the nickel-based alloy is 2 wt% or more and 5 wt% or less,
A method for manufacturing a sagger, further comprising a heat treatment step of heat-treating the sagger welded in the welding step in an oxygen atmosphere at an ambient temperature of 750 to 1000° C. for 5 to 10 hours. In the cutting step, one metal piece is cut in a developed state in which each side of the bottom surface and each side surface are connected,
Further comprising a bending step of bending the one metal piece cut in the cutting step between each side of the bottom surface and each side surface,
2. The method of manufacturing a sagger according to claim 1 , wherein in said welding step, each side surface included in said one metal piece bent in said bending step is welded. In the cutting step, the bottom surface and the four side surfaces are cut as separate metal pieces,
2. The method of manufacturing a sagger according to claim 1 , wherein in said welding step, welding is performed between each side of said bottom surface and each side surface and between each side surface. The method for manufacturing a sagger according to any one of claims 1 to 3, wherein in the welding step, welding is performed by TIG welding.

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