A saggar having a replaceable base for use in battery manufacturing

Abstract

There is disclosed herein a saggar (100) configured for use in processing materials for secondary cells, comprising a tray construction having a base (102) and a plurality of walls (104) surrounding the base (102), wherein the base (102) and the plurality of walls (104) are respectively configured for enabling a replaceable removal of the base (102) from the plurality of walls (104). By providing a base (102) that is removable, the walls (104) of the saggar (100) can be reused, and only the base (102) can be swapped out. Also disclosed herein is a method (400) to replace the base (102) of such a saggar (100), and a method (600) of processing materials (M) for a secondary cell, using such a saggar (100).

Description

A SAGGAR HAVING A REPLACEABLE BASE FOR USE IN BATTERY MANUFACTURINGTechnical Field

[0001] The present disclosure relates to the manufacture of secondary cells. More particularly, the present disclosure relates to a saggar having a replaceable base for use in the processing of battery materials, a method for repairing such a saggar, and a method of manufacturing a secondary cell using such a saggar.Background

[0002] Battery manufacturing processes require controlled thermal treatments to achieve desired material properties and ensure optimal battery performance. One critical aspect is the use of saggars, typically ceramic containers or crucibles, which provide a protective and controlled environment for materials during calcination and other thermal processes.

[0003] Saggars shield materials from direct contact with the furnace or kiln, minimizing contamination and preserving material integrity. They also act as a barrier against external gases, ensuring a controlled atmosphere for consistent material transformation.

[0004] Saggars facilitate efficient heat transfer, allowing precise temperature control and minimizing energy waste. Additionally, they provide mechanical support to delicate battery components, preventing deformation or damage during high-temperature processes.

[0005] Lithium, as used extensively during the production of secondary cells, penetrates the base of saggars, thereby corroding the base. After a certain amount of corrosion, the entire saggar may need to be disposed of.

[0006] Existing solutions to such a problem comprise selecting different materials for forming the saggar from, or for coating the saggar with, to mitigate the corrosion. However, such materials may be expensive and / or environmentally harmful.Summary

[0007] It is realized as part of the present disclosure that disposing of the entire saggar upon corrosion of the base is excessively wasteful, as the walls of the saggar do not corrode or degrade at the same rate as the base.

[0008] Thus, according to an aspect of the present disclosure, there is provided a saggar configured for use in processing materials for secondary cells, comprising a tray construction having a base and a plurality of walls surrounding the base, wherein the base and the plurality of walls are respectively configured for enabling a replaceable removal of the base from the plurality of walls.

[0009] By providing a base that is removable, the walls of the saggar can be reused, i.e. , only the base is swapped out. Accordingly, a great amount of material constituting the walls of the saggar can be advantageously preserved, thereby mitigating waste and reducing overall costs and environmental impact associated with the manufacture of secondary cells.

[0010] In preferred examples, the plurality of walls are formed as a single piece. Accordingly, the structure of the plurality of walls may be stronger, as there are no joining means, e.g., screws or plugs, which may become dislodged or damaged during processing (i.e., baking or firing) of the saggars.

[0011] The base and the plurality of walls are preferably respectively configured for enabling a slideable removal of the base from the plurality of walls. A slideable removable of the base is a particularly advantageous approach for removal and insertion of the base from the plurality of walls because saggars are conventionally processed along a conveying mechanism (such as a roller hearth kiln) that extends more in the width direction of the saggars than the height direction. Moreover, saggars are often stacked on top of each other for processing together. Hence, a vertical insertion / removal of the bases may require an unstacking of saggars or a movement of saggars into a location that has sufficient vertical clearance.

[0012] The slideable removability of base may be achieved in a variety of ways. In an example, one or more of the plurality of walls comprises a ridgefor supporting the base. The ridge may be formed as a lip at or near the lower edge of said one or more of the plurality of walls. The ridge may be processed or coated so as to provide a smoothed surface to further facilitate the sliding of the base therealong.

[0013] In some examples, the one or more of the plurality of walls additionally or alternatively comprises a slot for inserting the base. Hence, a lower edge of said wall may be retained (i.e. , below said slot) to provide greater stability of the plurality of walls, e.g., when placed on a flat surface without the base installed. Depending on the required gas flow around the saggar during processing, the slot may be closed by insertion of the based thereinto, or there may be a deliberate preservation of an opening in the slot even when the base is inserted therein. In cases where it is desired to achieve a substantially fluid-tight seal around the base of the saggar, ceramic glue, a band (e.g., of metal), or the like may be provided around the outside of the saggar.

[0014] To further aid in the insertion of the base, one or more edges of the base may comprise a taper configured to aid insertion of the base into the slot. Hence, when inserting the base, an edge having a taper may be moved into the slot such that, even if the base is slightly misaligned, the tapered edge of the base will contact an edge of the slot and slide thereagainst to thereby center the base in the slot as the base is pushed further into the slot.

[0015] Viewed from one perspective, it is appreciated that the base material being degraded is expensive, so it is desired to minimize the unnecessary disposal thereof. Therefore, the base may be prioritized for resilience, without wasting material on the sides, which can be made differently (e.g., thinner or from a different material) because they will wear down slower due to being less in contact with the materials being processed.

[0016] Viewed from another perspective, to minimize the unnecessary disposal of the base material, the base can be made as thin as possible to perform the function required of it in the processing of materials for use in battery cells, and the surrounding walls can be made differently (e.g., thicker or from a different material) to prioritize their structure and heat distribution,because their use cycle is longer due to being less in contact with the materials being processed.

[0017] According to an example implementation of the present disclosure, formulated according to this latter perspective, the plurality of walls comprises a base wall, and the base is a sacrificial base arranged on the base wall. The sacrificial base may thus be thinner than the base wall. In such an example, the chemical properties of the sacrificial base are exploited, but the thermal properties of the base wall can also be used. Hence, the sacrificial base can be made much thinner as it is not needed for said sacrificial base to provide structure or thermal distribution for the saggar.

[0018] It will thus be appreciated that the base may be made from a different material, such as metal, than the plurality of walls. In some examples, the plurality of walls and / or the base are formed from a nickel alloy. Such a nickel allow would preferably have a nickel content of 90 wt% or more, with the remainder comprising chromium, manganese, and / or other components. Forming the base and / or walls from metal advantageously allows for a faster heating of the saggar and faster spread of heat through the saggar.Moreover, a metal saggar is easier to manufacture and easier to dispose of, e.g., by recycling.

[0019] In some examples, the plurality of walls and / or the base are formed from a ceramic, wherein at least the base may comprise a coating on the ceramic. Ceramic saggars are well known as being able to provide good chemical and thermal properties, and a selective coating on the base may provide additional chemical resilience against degradation. A ceramic saggar may be made from silicon carbide (SiC), silicon nitride (SiN), alumina, cordierite, mullite, and / or zirconia or mixtures thereof.

[0020] According to a further aspect of the present disclosure, there is provided a method to replace the base of a saggar substantially as described above. The method comprises slideably removing a spent base from the saggar, and slideably installing a new base into the saggar.

[0021] According to a yet further aspect of the present disclosure, there is provided a method of manufacturing materials for a secondary cell. Themethod comprises heating material for use in the secondary cell in an oven or kiln, wherein the material is contained in a saggar substantially as described above. The material may comprise an alkali metal, preferably lithium, as saggars according to the present disclosure provide particular advantages when used for processing materials for battery manufacturing. For example, the material may comprise lithium hydroxide, lithium carbonate (LiCOs), or the like.Brief Description of the Drawings

[0022] 0ne or more embodiments of the present disclosure will be described, by way of example only, and with reference to the following figures, in which:

[0023] Figure 1 schematically shows a perspective view of an example embodiment of a saggar according to aspects of the present disclosure;

[0024] Figure 2 schematically shows another example embodiment of a saggar according to aspects of the present disclosure;

[0025] Figure 3 schematically shows yet another example embodiment of a saggar according to aspects of the present disclosure;

[0026] Figure 4 illustrates a method to replace the base of a saggar according to aspects of the present disclosure;

[0027] Figure 5 schematically shows an oven for heating materials for use in secondary cells, having therein saggars according to aspects of the present disclosure; and

[0028] Figure 6 illustrates a method of processing materials for a secondary cell according to aspects of the present disclosure.Detailed Description

[0029] The present disclosure is described in the following by way of a number of illustrative examples. It will be appreciated that these examples are provided for illustration and explanation only and are not intended to belimiting on the scope of the present disclosure. Instead, the scope of the present disclosure is defined by the appended claims.

[0030] Furthermore, although embodiments be presented individually for the sake of focused discussion of particular features, it will be recognized that the present disclosure also encompasses combinations of the embodiments described herein.

[0031] Figure 1 schematically shows a perspective view of an example embodiment of a saggar 100 according to aspects of the present disclosure.

[0032] The saggar 100 comprises a plurality of walls 104 comprising side walls 104a, 104b, 104c, and 104d, which form a cuboidal construction. Side walls 104a and 104c are shorter than side walls 104b and 104d in this example. However, it will be appreciated that the saggar 100 may, from a top / bottom view, have a square profile, or may have side walls 104a and 104c that are longer than side walls 104b and 104d.

[0033] In this example, the side walls 104 all have substantially the same height so as to form a flush profile at the top edge thereof. However, it will be appreciated that one or more of the side walls 104 may be shorter than the other(s), and / or one or more of the side walls 104 may comprise a notch or removed portion so as to facilitate gas flow to / from the saggar 100 if a like- shaped saggar is stacked thereupon.

[0034] Similarly, the side walls 104 may comprise shapings or protrusions on the top edge thereof that are configured to mate with or stably abut an underside of a like-shaped saggar thereupon. However, these particulars are outside of the scope of the present disclosure and thus are not discussed in detail herein. Instead, the illustrated saggars 100 have a flush and plain top edge.

[0035] The plurality of walls 104 are integrally formed as a single piece. The saggar 100 further comprises a base 102 that is removeable from the plurality of walls 104. Together, the base 102 and the walls 104 form a saggar 100 with a tray configuration. That is, the saggar 100 is configured to receive and hold material(s) for processing, e.g., in an oven, as is conventional for saggars.

[0036] Specifically, the base 102 is slideably removeable from the plurality of walls 104 by virtue of the longer side walls 104b and 104d each comprising a ridge 106 forming a lip at a bottom edge thereof. The ridge 106 extends at a right angle from the bottom edge of the side walls 104b and 104d and towards the respective opposite side wall, such that the base 102 can securely rest on the ridges 106. Although not shown in figure 1 , the side will 104c may also comprise a ridge.

[0037] Hence, the base 102 can be slideably inserted and removed from the plurality of walls 104. In some examples, the base 102 may be provided with grip-enhancing formations, which may be integrally formed or added to the base 102.

[0038] By placing the ridges 106 at the lower edge of the walls 104b and 104d, it can be seen that, even when the base 102 is removed, the saggar 100 can be stably placed at rest on a flat surface. Hence, the base 102 can be inserted and removed without needing to lift or otherwise manipulate the saggar 100, which may be hot from being in an oven.

[0039] Although the saggar 100 shown in figure 1 is oblong and configured for insertion / removal of the base along one axis (i.e., the elongated axis of the oblong profile), the saggar 100 may instead have a square profile, as discussed above. Moreover, the saggar 100 may be configured such that the base 102 can be inserted / removed in either direction, along both axes, i.e., along each of the walls 104. This may be particularly beneficial for a saggar 100 with a square profile.

[0040] In this way, the base 102 and the walls 104 may not need to have any particular orientation relative to each other. Thus, the insertion / removal of the base 102 may be greatly simplified (thereby enabling easier automation) because the base 102 would be able to be inserted along any edge, and in any orientation. In some preferred examples, the base 102 is also invertible such that it also functions upside down.

[0041] Figure 2 schematically shows another example embodiment of a saggar 100 according to aspects of the present disclosure. The numberingused in figure 2 corresponds to that used in figure 1 , and thus like-numbered components shown in both figure 1 and figure 2 may not be discussed in detail in the following.

[0042] The saggar 100 shown in figure 2 differs from that shown in figure 1 mainly in that the side wall 104a comprises a slot 202 instead of being open at the lower edge. The slot 202 is a through-hole into which the base 102 can be inserted. Hence, the slot 202 is dimensioned to have at least a same height and width as the base 102.

[0043] In the illustrated example, the slot 202 is configured to substantially match the cross-section of the base 102 such that an insertion of the base 102 into the slot 202 substantially seals the slot 202. Such an arrangement may be particularly advantageous if it is desired to prevent gas flow through the slot 202 during use of the saggar 100, and / or to prevent leakage of powder.

[0044] Although not shown, side wall 104c may have a similarly dimensioned slot extending part of or all of the way through the thickness of the wall 104c, such that the base 102 can be received and securely held therein. It will be appreciated that the wall 104c may instead have a ridge similar to the ridges 106 shown in figure 1 , and that the ridges 106 shown in figure 1 may be combined with the slot 202 shown in figure 2.

[0045] Figure 3 schematically shows yet another example embodiment of a saggar 100 according to aspects of the present disclosure. The numbering used in figure 3 corresponds to that used in figures 1 and 2, and thus like- numbered components shown in both figures 1 and 2, and figure 3, may not be discussed in detail in the following.

[0046] The saggar 100 shown in figure 3 differs from that shown in figure 2 mainly in that the plurality of walls 104 further comprises a base wall 104e, and an edge of the2 base 102 comprises a taper 302.

[0047] As this saggar 100 comprises a base wall 104e (which may also be integrally formed with the other walls 104a-d), it will be appreciated that the base wall 104e may be relied upon for providing most of the structural and / orthermal properties required for the saggar 100 to perform its function in processing materials for the manufacture of a secondary cell. Accordingly, the thickness Tb of the base 102 may be substantially thinner than the thickness Tbw of the base wall 104e.

[0048] Alternatively, the thickness Tbw of the base wall 104e may be substantially thinner than the thickness Tb of the base 102, and the same may be true for the thickness(es) of the other wall(s) 104a-d, so as to minimize the amount of material used to manufacture these walls 104. The walls 104 are not expected to degrade as quickly as the base 102, and thus, in this way, the resilience and strength of the base 102 may be prioritized over that of the walls 104.

[0049] The base 102 in this example has only one edge with a taper 302, although it will be appreciated that other edges of the base 102 could be similarly configured to allow for an ease of insertion in different orientations. It will be understood that the taper 302 helps in the centering of the base 102 in the slot 202 which, as discussed above, may be a tight fit. Hence, the rate at which bases can be removed and replaced can be increased. Indeed, the removal / insertion process may be automated for performance by, e.g., robotic means. The taper 302 may therefore reduce the precision tolerance required of any such robotic means.

[0050] Figure 4 illustrates a method 400 to replace the base of a saggar, such as any of the saggars 100 shown in figures 1 to 3, according to aspects of the present disclosure.

[0051] The method 400 comprises a step 401 of slideably removing a spent base from a saggar, and a step 402 of slideably installing a new base into the saggar.

[0052] The spent base may have been degraded over the course of one or more uses, depending on the configuration thereof. Hence, the method 400 may be performed with a variable frequency depending on the rate of degradation of the bases of the saggars. The degradation state of bases (and, optionally, saggars as a whole) may be dynamically assessed in realtime so as to identify saggars with spent bases. Alternatively, the bases and / or saggars may be tracked in respect of how many times they have been used to process materials, and a base may be considered as being ‘spent’ when it has undergone a predetermined number of use cycles.

[0053] It will be appreciated that, although slower than the base, the plurality of walls of the saggar will also degrade over time such that they will require being disposed of after a certain number of use cycles. Indeed, there may be a case where the walls are spent but the base is not. In such cases, the removability of the base from the walls is equally as advantageous as in the reverse case, because the base can be preserved as the walls are replaced with new walls. Accordingly, the walls may be monitored alongside / separately to the bases to assess their level of degradation.

[0054] In some examples, the method 400 may comprise inverting a base instead of installing a ‘new’ base. That is, it may be that only one side of the base is spent, so after the step 401 of removing the base, the base may be flipped over and re-inserted into the saggar. Such an approach may allow for the more efficient utilization of the bases, instead of allowing only one side of the base to degrade.

[0055] Figure 5 schematically shows an oven 500 for heating materials for use in secondary cells, having therein saggars 100 according to aspects of the present disclosure, which may correspond to the example saggars 100 shown in figures 1 to 3.

[0056] Figure 6 illustrates a method 600 of processing materials / Wfor a secondary cell according to aspects of the present disclosure. This method 600 may correspond to the illustrated system in figure 5, and hence references to figure 5 are also used to aid in understanding the method 600. The method 600 comprises heating material / Wfor use in a secondary cell, in an oven 500.

[0057] The oven 500 comprises a heating space 502 and a floor 504. The floor 504 may be static or may be moveable. That is, the oven 500 may be a roller hearth kiln or the like with a moving floor 504 that automatically movesthe saggars 100 through the heating space 502. The rate of such movement, the temperature of the heating space 502, and other factors may be configured depending on the process being applied to materials M in the saggars 100.

[0058] According to a typical use case, all of the saggars 100 have the same material M in them. In preferred examples, the material M is an alkali metal such as lithium (for use in secondary cells). Indeed, the saggars 100, having replaceable bases as described above, are particularly suited for use in processing materials / for a secondary cell.

[0059] As shown in figure 5, the saggars are stacked into piles, although the stacking of three saggars 100 on top of one another, shown in this figure, is purely exemplary, as is the number of piles. Hence, the volume of the heating space 502 can be most effectively utilized, and thus a throughput of the processing of materials / W ean be optimized.

[0060] It will be appreciated that, particularly in such a stacked configuration, a slideably removeable base may also advantageously allow for insertion / removal of the material M into and out of the saggars 100. Thus, the material M may be loaded onto a base and then placed into a saggar 100 that is to be inserted into the oven 500. Hence, the saggars 100 themselves may not be manipulated / moved during the processing of the materials M- the bases can be the only part that is moved / manipulated.

[0061] In a contemplated example, a plurality of saggars 100 may form a single structure that allows for the selective removal of the bases therefrom. That is, the structure may comprise multiple pluralities of walls, each of which is configured to receive a respective base. Bases, having material M loaded thereupon, may then be added to the structure before a passing of the structure into the oven 500.

[0062] Thus, it can be seen that a replaceable base may also greatly improve the flexibility of, and simplify, a method of processing materials / for a secondary cell, and hence the manufacture of secondary cells in general.

[0063] While the present disclosure is susceptible to various modifications and alternative forms, specific embodiments are shown and described above byway of example in relation to the drawings, with a view to clearly explaining the various advantageous aspects of the present disclosure. It should be understood, however, that the detailed description herein and the drawings attached hereto are not intended to limit the disclosure to the particular form disclosed. Rather, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the following claims.

Claims

C L A I M S1 . A saggar configured for use in processing materials for secondary cells, comprising: a tray construction having a base and a plurality of walls surrounding the base; wherein the base and the plurality of walls are respectively configured for enabling a replaceable removal of the base from the plurality of walls.

2. The saggar according to claim 1 , wherein the plurality of walls are formed as a single piece.

3. The saggar according to claim 1 or claim 2, wherein the base and the plurality of walls are respectively configured for enabling a slideable removal of the base from the plurality of walls.

4. The saggar according to any preceding claim, wherein one or more of the plurality of walls comprises a ridge for supporting the base.

5. The saggar according to any preceding claim, wherein one or more of the plurality of walls comprises a slot for inserting the base.

6. The saggar according to claim 5, wherein one or more edges of the base comprises a taper configured to aid insertion of the base into the slot.

7. The saggar according to any preceding claim, wherein the plurality of walls comprises a base wall, and the base is a sacrificial base arranged on the base wall.

8. The saggar according to claim 7, wherein the sacrificial base is thinner than the base wall.

9. The saggar according to any preceding claim, wherein the plurality of walls and / or the base are formed from a nickel alloy.

10. The saggar according to any preceding claim, wherein the plurality of walls and / or the base are formed from a ceramic.11 . The saggar according to claim 10, wherein at least the base comprises a coating on at least part of the ceramic.

12. The saggar according to any preceding claim, wherein the plurality of walls are formed from a different substance than the base.

13. A method to replace the base of a saggar according to any preceding claim, comprising: slideably removing a spent base from the saggar; and slideably installing a new base into the saggar.

14. A method of processing materials for a secondary cell, comprising: heating material for use in the secondary cell in an oven; wherein the material is contained in a saggar according to any of claims 1 to 12.

15. The method according to claim 14, wherein the material comprises an alkali metal, preferably lithium.

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