WO2021011453A1

WO2021011453A1 - Ignitor for exothermic welding

Info

Publication number: WO2021011453A1
Application number: PCT/US2020/041775
Authority: WO
Inventors: Nicholas Turner; Greg MARTINJAK; Steven ROIS; Christian Paul BARCEY
Original assignee: Erico International Corporation
Priority date: 2019-07-12
Filing date: 2020-07-13
Publication date: 2021-01-21

Abstract

An ignitor (20) for exothermic welding material can include a cartridge (22) with an open end (28), an ignition charge (30) of welding material disposed within the cartridge (22), and an ignition element (32) configured to ignite the ignition charge (30). A plug (36), such as can be formed from a hardened slurry of graphite material, can seal the open end (28) to retain the ignition charge (30) and the ignition element (32) within the cartridge (22).

Description

IGNITOR FOR EXOTHERMIC WELDING

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application No. 62/873,378, filed July 12, 2019, entitled "Ignitor for Exothermic Welding," the entirety of which is incorporated herein by reference.

BACKGROUND

[0002] Exothermic welding can be used in different settings to form high quality, high ampacity, and low resistance electrical connections between different conductors. In general, an exothermic welding process can fuse together separate conductors to provide a bond with a current carrying capacity substantially equal to that of the conductors themselves. Further, exothermic welds can be relatively durable and long-lasting, and can avoid problems of loosening and corrosion that can occur for mechanical and compression joints. As a result of these benefits, exothermic weld connections are widely used in grounding systems and other settings to enable connected sets of conductors to operate, effectively, as a continuous conductor with relatively low resistivity.

SUMMARY

[0003] Some embodiments of the invention provide an ignitor for exothermic welding material that includes a cartridge with an open end, an ignition charge of welding material disposed within the cartridge, an ignition element configured to ignite the ignition charge, and a plug. The plug can be formed from a hardened slurry of graphite material that seals the open end to retain the ignition charge and the ignition element within the cartridge.

[0004] In some embodiments, a cartridge can be closed except at an open end, such that an ignition charge is fully enclosed by the cartridge and a plug that seals the open end.

[0005] In some embodiments, no air gap may be provided between a plug and an ignition charge.

[0006] In some embodiments, welding material of an ignition charge may not be classified as a division 4.1 flammable solid. [0007] In some embodiments, a slurry that forms a plug can be formed from materials including one or more of: graphite fines or sodium silicate.

[0008] In some embodiments, a plug can retain an ignition element in contact with an ignition charge.

[0009] In some embodiments, an ignition element can include a conductive filament that is electrically connected to electrical leads extending outside of the cartridge.

[0010] In some embodiments, electrical leads can extend through a plug.

[0011] In some embodiments, a cartridge can be a metal-walled cartridge.

[0012] In some embodiments, an ignitor can be configured to be installed for ignition of a main charge of welding material with a plug opposite an ignition charge from the main charge.

[0013] Some embodiments of the invention provide an ignitor for exothermic welding material that includes a metal cartridge with a closed end and side walls that collectively define an internal cartridge area. An ignition charge of welding material can be disposed within the internal cartridge area and an ignition element can be configured to ignite the ignition charge. A plug of graphite material can be formed between the side walls, opposite the closed end, to close the internal cartridge area.

[0014] In some embodiments, an ignition element can extend through a plug to contact an ignition charge.

[0015] In some embodiments, an ignition element can include a conductive filament embedded within an ignition charge and electrical leads that can extend through a plug.

[0016] In some embodiments, a plug can be formed from a slurry that includes graphite particles and a binder.

[0017] In some embodiments, a welding material of an ignition charge can be powdered welding material. [0018] Some embodiments of the invention provide a method of manufacturing an ignitor for exothermic welding material. The method can include providing a cartridge that includes side walls and an open end, at least partly filling the cartridge with an ignition charge of welding material, and disposing an ignition element for ignition of the ignition charge. A slurry of graphite material can be directed into the open end of the cartridge, and cured to form a hardened plug at the open end of the cartridge, to retain the ignition charge within the cartridge.

[0019] In some embodiments, a slurry can be cured to form a hardened plug so that no air gap is provided between the plug and an ignition charge.

[0020] In some embodiments, a cartridge can include a closed end opposite an open end, so that a plug at the open end, side walls, and the closed end fully enclose an ignition charge within the cartridge.

[0021] Some embodiments of the invention provide a welding apparatus for exothermic welding. A welding mold can include a crucible to receive a main welding charge of welding material, and a welding chamber that is configured to receive one or more conductors to be welded. An ignitor can be provided to ignite the main welding charge, and can include a cartridge for an ignition charge of welding material and a plug of graphite material to seal the cartridge.

[0022] In some embodiments, a welding mold can include a lid for a crucible. A lid can include an ignition port that is configured to receive an ignitor to hold the ignitor above a main welding charge.

[0023] In some embodiments, a plug of an ignitor can substantially block an ignition port in a welding mold when the ignitor is received in the ignition port.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of embodiments of the invention:

[0025] FIG. 1 is an isometric ignitor for exothermic welding material, including a cartridge and a plug, according to an example of this disclosure; [0026] FIG. 2 is an isometric view of the ignitor of FIG. 1, with the cartridge not shown to illustrate aspects of a plug and an internal ignition charge of welding material;

[0027] FIG. 3 is an isometric view of the insert ignitor of FIG. 1, with the cartridge rendered transparently and the ignition charge not shown;

[0028] FIG. 4 is a cross-sectional view of a welding apparatus that includes the ignitor of FIG. 1, according to an example of this disclosure;

[0029] FIG. 5A is a side elevation view of another ignitor for exothermic welding material, including a cartridge, according to an example of this disclosure;

[0030] FIG. 5B is a side elevation view of the ignitor of FIG. 5A, with the cartridge not shown; and

[0031] FIG. 5C is a side elevation view of the ignitor of FIG. 5A with the cartridge and an ignition charge of welding material not shown.

DETAILED DESCRIPTION

[0032] Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or“having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms“mounted,”“connected,”“supported,” and“coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and“coupled” are not restricted to physical or mechanical connections or couplings.

[0033] The following discussion is presented to enable a person skilled in the art to make and use embodiments of the invention. Various modifications to the illustrated embodiments will be readily apparent to those skilled in the art, and the generic principles herein can be applied to other embodiments and applications without departing from embodiments of the invention. Thus, embodiments of the invention are not intended to be limited to embodiments shown, but are to be accorded the widest scope consistent with the principles and features disclosed herein. The following detailed description is to be read with reference to the figures, in which like elements in different figures have like reference numerals. The figures, which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of embodiments of the invention. Skilled artisans will recognize the examples provided herein have many useful alternatives that may fall within the scope of embodiments of the invention.

[0034] As discussed above, exothermic welding can be used to connect together metal structures, such as copper conductors of an electrical system. Generally, exothermic mixtures can include a combination of a reductant metal and a transition metal oxide, which react exothermically upon ignition to initiate and then sustain a continuing reaction of the mixture. The resulting molten metal can be used to create a useful weld, such as may be controlled using a non-fusible (e.g., graphite) mold. Or, in some configurations, the resulting heat can be used directly.

[0035] As one example, some conventional mixtures of exothermic welding material can include aluminum and copper oxide. Upon ignition, the resulting exothermic reaction can provide a mixture of molten copper and aluminum oxide, or slag. The molten copper, which has a higher density than the slag, can accordingly be directed by a mold to weld together metal conductors (e.g., copper to copper or steel to steel). The less dense aluminum oxide slag is generally removed from the weld connection and discarded. As another example, other conventional mixtures can include iron oxide and aluminum, which can react with similar effect.

[0036] To initiate an exothermic reaction of welding material, ignition energy must be provided to the welding material. In conventional systems, for example, powdered starting material can be configured as a special fine-grained formulation of welding material that is highly combustible (i.e., relatively easily ignitable). Such starting material can, for example, be sprinkled onto a main charge of standard welding material and can then be ignited using electrical or mechanical devices (e.g., a flint gun or an arc ignitor). The heat of the resulting reaction can then ignite the main charge of welding material so that a weld can be formed. Or, alternatively, an ignition device can be used to directly supply activation energy to a main charge of welding material (e.g., as may include a mixture of starting and non-starting welding material).

[0037] In some cases, conventional approaches to igniting welding material can introduce complexity, cost, or other issues to welding processes. For example, management and use of starting powder can be generally difficult for operators, including due to the tendency of the fine grained material to disperse from optimal locations (e.g., during transport). Such dispersal, in particular, can sometimes render the starting powder useless for igniting a main welding charge. Further, due to the highly combustible nature of starting powder (e.g., classified as a division 4.1 flammable solid under United Statues regulation 49 CFR § 173.124), ignitors that use starting powder may require enhanced safety precautions during manufacture, transport, and storage, even when fully enclosed in packaging. Further, in some cases, implementing arc ignition may require substantial electronic circuitry, including relatively expensive capacitors or other devices.

[0038] Embodiments of the invention can address these and other issues. For example, some examples can be configured as self-contained ignitors, with a cartridge that contains an ignition charge of welding material, an ignition element, and a plug. The plug can be formed from a non flammable and non-fusible composition and can be disposed both to maintain the ignition charge within the cartridge and to maintain the ignition element in appropriate alignment with the ignition charge (e.g., in contact with the welding material within the cartridge). With a cartridge thus arranged, for example, the plug can ensure that the welding material of the ignition charge remains in the cartridge until ignited and that the ignition element is appropriately disposed to ignite the ignition charge.

[0039] In some examples, a self-contained ignitor can be formed with a cup-shaped cartridge that includes a closed end, closed side walls, and a single open end and is at least partly filled with an ignition charge of welding material. The cartridge can be formed to include fusible material, such as a jacket of copper or other metal, so that molten material from reaction of the ignition charge can melt through the cartridge to reach and ignite a main welding charge.

[0040] In some examples, a plug can be formed from graphite material (e.g., a composition of graphite and other substances) to close an open end of a cartridge and thereby seal an ignition charge within the cartridge. Some plugs can also help to direct flow of the molten products of the eventual reaction of the ignition charge towards a main charge of welding material. For example, graphite is generally non-fusible and very difficult to combust, particularly in the transient-heating and limited-oxygen environment of exothermic welding conditions. Accordingly, a graphite plug can help to ensure that the molten welding material from the ignition charge is directed primarily to melting or otherwise consuming material of the cartridge opposite the plug. Correspondingly, a generally non-combustible (in the intended environment) and non-fusible plug can help to reduce (e.g., eliminate) expulsion of molten material from the ignition charge in the direction of (and past) the plug.

[0041] In some examples, a plug can be formed from a hardened slurry of graphite material, such as a slurry of graphite particles and a binder (e.g., sodium silicate). In some examples, graphite fines (i.e., particles with median diameter of less than 150 pm) can be used, such as may be available as waste product of other manufacturing processes. In this regard, for example, a non flammable, non-fusible plug can be relatively easily formed while making use of otherwise- wasted material that may independently have little saleable value.

[0042] The use of slurry to form a plug can also provide other benefits. For example, when slurry is initially poured into a cartridge, the slurry can naturally settle onto and (as applicable) around an ignition charge within the cartridge. Accordingly, when the slurry has hardened into a solid plug, there may be no air gap between the plug and the ignition charge, which may provide various benefits. For example, with no air gap between the plug and the ignition charge, there may be negligible gases present that might otherwise pressurize the cartridge as the ignition charge reacts. Additionally, with the elimination of empty space within a cartridge, it may be possible to ensure continuous engagement (e.g., contact) between an ignition element and an ignition charge regardless of the current orientation of the cartridge. Accordingly, some embodiments can be reliably used for ignition even after relatively rough transport or other physical disturbances.

[0043] In some examples, a plug may continue to secure part or all of an ignition element, such as an initially closed-circuit filament of tungsten or other material, even after ignition of an ignition charge of welding material within a cartridge. For example, a non-fusible and generally non combustible plug, such as may be formed from hardened graphite slurry, can remain largely intact after reaction of the associate ignition charge and can, correspondingly, continue to secure any non-consumed parts of an ignition element along with attached parts of the cartridge. This may, for example, help to ensure that parts of the ignition element do not fall into the weld being formed, or otherwise interfere with welding operations.

[0044] In some examples, use of a non-fusible and generally non-combustible plug, such as a plug formed from graphite slurry, can have other benefits. For example, some examples can include a graphite welding mold with a crucible to hold a main welding charge, a lid to cover the crucible, and an ignition port within the lid to receive an ignitor for ignition of the main welding charge. With appropriate configuration, the graphite (or other) material of a plug of the ignitor can effectively fill a cross-section of the ignition port and thereby reduce (e.g., eliminate) expulsion of welding material from the crucible through the ignition port during welding operations.

[0045] In some examples, a self-contained ignitor can be configured as a self-contained ignitor and main welding charge. For example, an ignitor such as generally described above may sometimes include a welding charge that is large enough to provide sufficient material to form a desired weld. Accordingly, for example, rather than an ignition element igniting an ignition charge that then ignites a separate main welding charge, the ignition element can be arranged to ignite an ignition charge that is also a main welding charge, with the reaction of an ignition/welding charge directly providing molten material to form a weld.

[0046] FIGS. 1-3 illustrate aspects of a self-contained ignitor 20 for initiating exothermic reactions in main welding charges for exothermic welding. The ignitor 20 includes a cartridge 22 that is formed (e.g., die drawn) as a copper cup with cylindrical side walls 24, a closed end 26, and an open end 28 with a flared mouth. As shown in FIG. 2 in particular, an ignition charge 30 substantially fills the cartridge 22.

[0047] In some examples, an ignition charge can be formed from welding material with similar constituents as a main welding charge (not shown in FIGS. 1-3), such as a conventional mixture of exothermic welding material. In some examples, a composition of an ignition charge can be a somewhat adjusted formulation as compared to a main welding charge, such as may result in comparatively large heat generation. In some examples, an ignition charge can be formed differently than conventional starting material for exothermic welding, such that the ignition charge may not be classified as a flammable solid. [0048] As shown in particular in FIG. 3, the ignitor 20 also includes an ignition element 32. In some examples, it can be useful to form an ignition element from a conductive filament in a closed- circuit configuration with external electronics (not shown). For example, the ignition element 32 is formed as a partially looped (e.g., U-shaped) tungsten filament, with electrical leads 34 that separately extend through a plug 36. This arrangement, and other closed-circuit arrangements, can allow for ignition of the ignition charge with relatively low power, such as may allow the use of simple battery-powered ignitors without complex circuitry, large capacitors, or other expensive or bulky electronics. Further, a closed-circuit arrangement can help the ignitor element to retain a desired shape and orientation, such as may be helpful to ensure continuous contact between the ignitor element and an ignition charge, even without the use of biasing elements such as springs.

[0049] As also noted above, the ignitor 20 includes a plug 36. In particular, the plug 36 is disposed to close the open end 28 of the cartridge 22, and thereby to seal the ignition charge 30 within the cartridge 22. As illustrated in FIGS. 1-3 collectively, the plug 36 secures the ignition charge 30 within the cartridge 22, with the tungsten filament of the ignition element 32 embedded within the ignition charge 30 and with the electrical leads 34 extending through the plug 36 to the exterior of the cartridge.

[0050] Thus, for example, by forming a complete seal with the side walls 24 and at the ignition charge 30, the plug 36 can prevent the material of the ignition charge 30 from escaping the cartridge 22. Further, the embedding of the ignition element 32 in the plug 36 can ensure that the ignition element 32 remains fixed in the intended position until (and while) it is used to ignite the ignition charge 30, with easy connection points at the electrical leads 34 to receive power from external ignition electronics. Secure engagement of an ignition element by a plug can also help to secure the ignition element against loss (e.g., incorporation into a weld).

[0051] Further, as shown in FIG. 2 in particular, the plug 36 can be formed with no air gap between the ignition charge 30 and the plug 36 (or other features at the open end 28 (now closed by the plug 36) of the cartridge 22. Thus, there is no substantial amount of air to become super heated and thereby highly pressurized, during reaction of the ignition charge 30.

[0052] Appropriately configured plugs can also provide benefits during welding operations.

For example, being formed as a non-fusible and non-consumable body, the plug 36 can effectively serve as a non-melting lid that remains intact during the reaction of the ignition charge 30 and the subsequent melting of the closed end 26 of the cartridge 22 (i.e., for the molten products of the ignition charge 30 to fall onto a main welding charge). Thus, the plug 36 can provide a barrier that prevents the products of the potential highly volatile reaction of the ignition charge 30 from escaping the cartridge 22 at any point except through a melted opening at the (formerly) closed end 28.

[0053] In some examples, as also noted above, a plug can be formed from graphite material, such as a composition of graphite and other components. As illustrated, for example, the plug 36 is formed from hardened graphite slurry that includes an approximate (i.e., within 15%) equal ratio of graphite fines and binder, such as a 40% aqueous solution of sodium silicate. Accordingly, during manufacture of the ignitor 20, the ignition charge 30 can be filled into the cartridge, the ignition element 32 oriented for use, and a slurry poured and hardened to form the plug 36. The use of slurry, such as to form the plug 36, can allow for relatively easy construction of an ignitor, including because the flowable nature of the slurry can help to automatically and substantially eliminate air gaps between an ignition charge and a plug, and to ensure reliable (e.g., surrounding) engagement of an ignitor element of any variety of configurations.

[0054] In other examples, other configurations are possible. For example, some cartridges can be formed in other shapes or from other materials. Similarly, different types of graphite (or other) materials can be used for a plug, including for plugs that are formed in different ways than the plug 36. Additionally, ignitors other than tungsten filaments can be used and, although closed-circuit ignitor elements may be useful in many cases, other approaches are possible.

[0055] FIG. 4 illustrates an example welding apparatus 40 that is configured for use with the ignitor 20. In particular, the apparatus 40 includes a graphite mold 42 with a lid 44 that can hinge to open a crucible 46, and a welding chamber 48 with conductor openings 50 to receive conductors (not shown). The lid 44 is generally solid, but includes an ignition port 52 that extends from the outside of the lid 44 to the top of the crucible 46.

[0056] As illustrated in FIG. 4, an ignitor such as the ignitor 20 can be disposed in the ignition port 52. In particular, the flared mouth of the cartridge 22 can help to secure the ignitor 20 against slipping through the ignition port 52, with the plug 36 substantially blocking the open top end of the ignition port 52 and the ignition charge 30 suspended within the ignition port 52 above the crucible 46.

[0057] With the apparatus 40 thus arranged, a main welding charge, such as a self-contained welding cup 54 filled with welding material, can be disposed within the crucible 46. The ignition charge 30 can then be ignited using the ignition element 32 (see, e.g., FIG. 3), with the heat of the resulting reaction melting through the cartridge 22 opposite the plug 36 so that molten welding material falls from the cartridge 22 onto the welding cup 54. The heat of this welding material can then ignite welding material within the welding cup 54 (e.g., after melting through a top of the cup 54), so that exothermic welding of conductors (not shown) within the welding chamber 48 can be completed. During the welding process, the ignition charge 30 can remain within the ignition port 52, to help prevent expulsion of products via the ignition port 52. The ignitor 20, with the cartridge 22 now partially melted and empty of welding material and the plug 36 retaining any non-consumed pieces of the cartridge and the ignition element 32, can then be removed from the lid 44 and discarded.

[0058] As also noted above, in other examples, other configurations are possible. For example, FIGS. 5A-5C illustrate aspects of another ignitor 60 according to an example of the disclosure. In the example illustrated, the ignitor 60 includes a cup-shaped copper cartridge 62, which is configured to contain an ignition charge 64 of welding material (e.g., not conventional starting powder). An ignition element 66 with strip-like electrical leads 68 extends into the cartridge 62 so that a closed-circuit filament 70 is embedded into the ignition charge 64. Further, a plug 72, such as may be formed from a slurry of graphite material, is formed at an open end of the cartridge 62 to fully seal the ignition charge 64 within the cartridge and to secure the ignition element 66 relative to the cartridge 62 and the ignition charge 64. Thus arranged, the ignitor 60 can be implemented similarly to the ignitor 20 (see FIGS. 1-3), or otherwise, with similar benefits.

[0059] Thus, the disclosed ignitors and apparatus for welding can provide improved functionality and handling, and more economical manufacturing and transport, as compared to conventional systems. For example, self-contained ignitors with plugs according to some embodiments can allow for easier and more reliable ignition of welding materials, including after jostling or other disturbances during transport and use. Further, some configurations can help to ensure that the energy of the reaction of an ignition charge of welding material is primarily and efficiently directed towards ignition of a main charge of welding material to execute exothermic welding operations.

[0060] The previous description of the disclosed examples is provided to enable any person skilled in the art to make or use the invention. Various modifications to these examples will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other examples without departing from the spirit or scope of the invention as defined by the claims below. Thus, the invention is not intended to be limited to the examples shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein and the claims below.

Claims

1. An ignitor (20) for exothermic welding material comprising:

a cartridge (22) with an open end (28);

an ignition charge (30) of welding material disposed within the cartridge (22);

an ignition element (32) configured to ignite the ignition charge (30); and

a plug (36) that includes graphite material and closes the open end (28) to retain the ignition charge (30) and the ignition element (32) within the cartridge (22).

2. The ignitor (20) of claim 1, wherein the cartridge (22) is closed except at the open end (28), such that the ignition charge (30) is fully enclosed by the cartridge (22) and the plug (36).

3. The ignitor (20) of any of the preceding claims, wherein no air gap is provided between the plug (36) and the ignition charge (30).

4. The ignitor (20) of any of the preceding claims, wherein the ignition charge (30) includes powdered welding material and optionally or preferably is not classified as a division 4.1 flammable solid (44).

5. The ignitor (20) of any of the preceding claims, wherein the plug (36) is formed from a hardened slurry that includes the graphite material.

6. The ignitor (20) of claim 5, wherein the hardened slurry is formed from materials including graphite fines and a binder, and optionally or preferably wherein the hardened slurry includes sodium silicate.

7. The ignitor (20) of any of the preceding claims, wherein the plug (36) retains the ignition element (32) in contact with the ignition charge (30), and optionally or preferably wherein the ignition element (32) includes a conductive filament.

8. The ignitor (20) of any of the preceding claims, wherein electrical leads (34) for energizing the ignition element (32) extend through the plug (36).

9. The ignitor (20) of any of the preceding claims, wherein the cartridge (22) is a metal-walled cartridge (22).

10. A welding apparatus for exothermic welding, the welding apparatus comprising: a welding mold (42) that includes a crucible (46) to receive a main welding charge of welding material, and a welding chamber that is configured to receive one or more conductors to be welded; and

an ignitor (20) according to any of the preceding claims.

11. The welding apparatus of claim 10, wherein the welding mold (42) includes a lid (44) for the crucible (46); and

wherein the lid (44) includes an ignition port (52) that is configured to receive the ignitor (20) to hold the ignitor (20) above the main welding charge.

12. The welding apparatus of claim 11, wherein the plug (36) of the ignitor (20) blocks the ignition port (52) when the ignitor (20) is received in the ignition port (52).

13. A method of manufacturing an ignitor (20) for exothermic welding material, the method comprising:

providing a cartridge (22) that includes side walls and an open end (28);

at least partly filling the cartridge (22) with an ignition charge (30), the ignition charge (30) being optionally or preferably formed of welding material;

disposing an ignition element (32) within the cartridge (22) for ignition of the ignition charge (30);

directing a slurry of graphite material into the open end (28) of the cartridge (22); and curing the slurry to form a hardened plug (36) at the open end (28) of the cartridge (22), to retain the ignition charge (30) within the cartridge (22).

14. The method of claim 13, wherein the slurry is cured so that no air gap is provided between the hardened plug (36) and the ignition charge (30) and optionally or preferably so that leads (34) for the ignition element (32) extend through the hardened plug (36).

15. The method of either of claims 13 or 14, wherein the slurry includes graphite fines and a binder.