WO2017147713A1 - Anodic and cathodic canisters for a liquid metal battery and method of manufacturing a liquid metal battery - Google Patents

Abstract

A liquid metal battery and method of manufacture is provided for avoiding containment interface failures. An anodic canister houses an anodic metal, a lower cathodic canister houses a cathodic metal, and an electrolyte layer disposed between the anodic metal and cathodic metal. The anodic canister is coupled to the cathodic canister at a sealing interface adjacent the electrolyte layer. Inner surfaces of the anodic and cathodic canisters are electrically conductive and having electrical isolation therebetween.

Description

ANODIC AND CATHODIC CANISTERS FOR A LIQUID METAL BATTERY AND METHOD OF MANUFACTURING A LIQUID METAL BATTERY

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001 ] This application claims the benefit of U.S. Provisional Application No. 62/302,762 filed March 2, 2016 and U.S. Provisional Application No. 63/302,748 filed March 2, 2016, the contents of both of which are herein incorporated by reference in their entireties.

FIELD

[0002] The current embodiments relate generally to liquid metal batteries, and more specifically to liquid metal battery canisters and methods of manufacturing the same.

BACKGROUND

[0003] A molten salt battery is a class of battery that uses a molten salt electrolyte, such as the one shown in Figs. 1 , 1A and 1 B. The components of molten salt batteries are solid and inactive at room temperature, and as long as the salt electrolyte is solid, the battery is inert and remains inactive. This allows the battery to be stored inactive for long periods of time.

[0004] In addition to an anode, a cathode, and a salt electrolyte, each cell also contains a pyrotechnic heat source to activate the cell by heating the cell to the typical operating temperature of 400-550°C. During thermal or pyrotechnic l activation through heating and liquefaction of the components, the cathode, anode and electrolyte layers separate due to their relative densities and immiscibility. The result is three vertically stratified components: an upper liquid metal, the intermediate salt, and a lower liquid metal.

[0005] For example, the conventional molten salt battery or liquid metal battery 100 of Fig. 1 uses liquid metals as the anode 102 and the cathode 104, which are solid at room temperature, but liquefy upon activation. In a discharged state, the anode 102 could be, for example, pure magnesium (Mg), and the cathode 104 could be, for example, a magnesium-antimony (Mg-Sb) alloy. The molten salt layer between the upper liquid metal and the lower liquid metal serves as an electrolyte 106 with a high ionic conductivity and is the medium through which the ionic species travel as the battery 100 charges and discharges.

[0006] During charging of the cell 100, magnesium ions (Mg2+) can move from the cathode 104, through the molten salt layer 106, to the anode 102. When fully charged, as shown in Fig. 1A, the anode 102a can be pure magnesium and the cathode 104a can be pure antimony.

[0007] During discharge of the cell 100, magnesium ions (Mg2+) can move from the anode 102, through the molten salt layer 106, to the cathode 104. While discharging, electrons travel from the negative current collector 1 12, which acts as a conductive cover to the anode 102, through the load 1 18 to provide electricity to the load 1 18, and then to the positive current collector 1 14, which acts as a conductive cover to the cathode 104. When discharged as shown in Fig. 1 B, the anode 102b can be pure magnesium and the cathode 104b can be a magnesium-antimony alloy. An annular insulating (refractory) lining or sheath 124 is typically provided between the positive current collector 1 14 and the anode 102, electrolyte 106, and cathode 104. A ceramic insulator 122 is provided to separate the positive current collector 1 14 and the negative current collector 1 12, so as to prevent an electrical short circuit.

[0008] Fig. 2 illustrates a more general example of a conventional liquid metal battery 200. The negative electrode 202 is shown on the top, and can be a low- density metal that readily donates electrons referred to as "Metal A". The positive electrode 204 is shown on the bottom and can be a higher-density metal that readily accepts electrons referred to as "Metal B". The electrolyte 206 between the anode 202 and cathode 204 is a molten salt. During discharge, Metal A loses electrons (e-), becoming ions (A+) that travel through the electrolyte 206 to the bottom electrode 204. The electrons pass through an external circuit, powering an electric load 218 on the way.

[0009] At the bottom electrode 204, the Metal A ions and electrons rejoin and then alloy with the Metal B electrode. Thus, when the battery 200 discharges, the top layer of molten metal 202 gets thinner and the bottom layer of molten metal 204 gets thicker (See Figs. 1A Charged and 1 B Discharged); when the battery 200 charges, the relative thicknesses reverse. A vapour space 230 above the upper liquid metal 202 is provided to allow for movement of the liquid metal level and movement of the metal components between liquid operating and solid storage states. An annular insulating sheath 224 and a ceramic insulator 222 are also shown.

[0010] The ability to store unactivated batteries using liquid metal batteries has the double benefit of avoiding deterioration of the active materials during storage and eliminating capacity loss due to self-discharge until the battery is activated. Furthermore, as the components are liquid, the transfer of electrical charges and chemical constituents within each component and from one to another is extremely fast, permitting the rapid flow of large currents into and out of the battery. Compared to solid-form batteries, liquid metal batteries have a long storage life, exhibit a high current density, have a long cycle life, and are relatively simple to manufacture.

[001 1 ] However, liquid metal batteries can be difficult to use and maintain. A high operating temperature must be maintained during their activation and use and further difficulties are experienced in the maintenance of electrical continuity between the electrodes if they are cycled between solid and liquefied states. Specifically, troublesome internal battery components such as an insulating refractory liner, an anode electrode collector antenna, or an intrusive sealing mechanism through the anode wall and on the roof of the cell can be subject to failure.

[0012] For example, and with reference to Fig. 2, typically a negative current collector 212 is sealably inserted through the top of, and supported from, the battery 200 into the upper liquid metal anode 202. The negative current collector 212 allows electrons to leave the anode 202 to supply current to the load 218 and then travel to the positive current collector 214 and into the cathode 204.

[0013] The vapour space 230 above the upper liquid metal 202 can contain highly corrosive and reactive off-gas that needs to be sealed from egress. The negative current collector 212 that extends through the containment canister is particularly subject to off-gas corrosion, with the corrosive off-gas attacking the containment mechanisms at their challenging anode-electrode seal between the outside environment and the anode vapour space 230.

[0014] Such points of weakness that are vulnerable to off-gas corrosion, and therefore heightened risk of failure, can be created through the manufacturing process of conventional molten salt batteries. Specifically, the welding-brazing procedures used in the cell fabrication can damage the material composition and associated structural integrity in various affected areas, including at the seal between the anode and cathode or the negative current collector and positive current collector. Conventional fabrication of these batteries can result in cracks that provide opportunities for the corrosive vapour to attack compromised areas with premature or accelerated electro-chemical corrosion. Thermal cycling and metal fractures associated with the corrosive environment and elevated operating temperatures can result in premature, if not almost immediate, seal failures attributable to chemical corrosion. Failure of the seal can allow air to leak into each individual cell, damaging the cell and rendering it inoperable. [0015] It would be advantageous to have a liquid metal battery that is not vulnerable to failure at the interfaces between the electrodes in a corrosive off-gas environment above a liquid metal anode, and that can more easily accommodate the mobile liquid metal level and movement of the metal components between the liquid operating and solid storage states.

SUMMARY

[0016] Herein, Applicant's liquid metal battery ("LMB") is a class of developmental battery technology that can increase storage capacity and life span, maintain high current density, and greatly reduces the cost of manufacture and maintenance. In embodiments disclosed herein, elements of the LMB are horizontally-stratified between a light liquid-metal anode (e.g., lithium) overlying a salt electrolyte (e.g., lithium iodide or lithium chloride) overlying as dense liquid- metal cathode (e.g., lead or antimony).

[0017] The components are solid at room temperature and gravity segregate upon melting due to their relative densities and immiscibility. Compared to solid batteries, the raw materials of Applicant's LMB are readily available and inexpensive. Individual LMB Containment Units CU's can also be physically "stacked" allowing for modular flexibility. These characteristics allow for economies of scale and mass production of low-cost energy storage that can accommodate a wide range of storage requirements by simply varying the number of LMB CUs used.

[0018] While promising in concept, existing LMB technologies have yet to achieve commercialization due to significant design flaws in their containment units. To ensure electrical insulation between the anode and cathode, a ceramic insulator is usually placed at the top of the LMB anode, but these have demonstrated premature failure. Applicant believes the failure is due to the presence of a gaseous vapour space above the upper liquid metal anode that allows for expansion of the salts and metals, the vapour being highly corrosive and needs to be sequestered from the CU metal housing, and that the salt and metal components expand and contract during operation, particularly upon phase change and exert significant forces on the CU walls.

[0019] Herein, a containment strategy is provide that overcomes the aforementioned problems observed in existing designs. In embodiments, to prevent exposure to the upper corrosive vapour space, an insulating ceramic coating is added to the distal inner walls of each half of the CU and between the interface used to assemble the cathode and anode.

[0020] In another embodiment, canisters having a generally cylindrical inner wall, with a curved bottom, avoid stress concentrations experienced during thermal expansion as the CU is heated from ambient to operating temperature of around 400°C. The anode (upper half of the CU) can also include a protrusion to ensure electrical contact with the liquid anode metal, even in the presence of vapour space.

[0021 ] Applicant ensures electrical isolation between the anode and cathode under harsh thermal cycling conditions.

[0022] Accordingly, and generally, anodic and cathodic canisters for a liquid metal battery are provided, the anodic and cathodic canisters together forming a containment unit that can improve mechanical containment, can improve electro- chemical stability and reduce corrosion, and can better tolerated thermal cycles in liquid metal batteries. The liquid metal battery can further eliminate the need for troublesome internal battery components including prior art use of insulating refractory liners, anode electrode collector antennae, and intrusive and sealing mechanisms through the anode wall and on the roof of the cell. This can be accomplished by using an upper conductive canister and an electrolyte (liquid salt) layer as the point of contact between the anodic and cathodic metals. The current arrangement isolates the materials from one another and alleviates the prior art primary failure mechanisms including those exacerbated by degraded canister materials exposed to vapor off-gas corrosion.

[0023] In an aspect, a liquid metal battery comprises an upper electrically conductive anodic canister housing an anodic metal, a lower cathodic canister housing a cathodic metal, an electrolyte layer disposed between the anodic metal and cathodic metal, and a liquid seal coupling the anodic canister to the cathodic canister at an interface adjacent the electrolyte layer.

[0024] In a further aspect, a method of manufacturing a liquid metal battery comprises the steps of providing a housing comprising an upper electrically conductive anodic canister and a lower cathodic canister, receiving a cathodic metal in the housing, receiving an electrolyte in the housing, receiving an anodic metal having a density lower than the cathodic metal in the housing, and sealingly coupling the anodic canister to the cathodic canister, wherein the interface between the anodic canister and the cathodic canister is disposed adjacent the electrolyte. [0025] Forming a seal between upper and lower canisters at the electrolyte area, rather than forming a seal above the anode electrode, and using an upper conductive canister can help to avoid seal failures at the anode electrode. Use of a threaded or compression seal about an upper and lower canister interface eliminates sealing mechanisms previously subjected to corrosive off-gas vapours. The seal and electrical isolation now occurs within the electrolyte region, with the seal being a fluid seal rather than a vapour seal. The implementation of an upper conductive canister can also resolve multiple problems by simplifying the structural design of the liquid metal battery, eliminating the container-penetrating electrode concept and instead moving the electrical isolation mechanisms to the interconnection of the anodic and cathodic canisters.

[0026] In one broad aspect, A liquid metal battery is provided comprising an upper canister housing having an electrically conductive inner surface, a lower canister housing an electrically conductive inner surface;, electrical isolation between the electrically conductive inner surfaces of the upper and lower canisters; and a liquid seal coupling the upper and lower canisters. The coupled upper and lower canisters house an upper anodic metal and a lower cathodic metal respectively for electrical conductively therebetween, having and an electrolyte layer disposed between the anodic metal and cathodic metal, all of which are molten in operation, the molten electrolyte layer remaining adjacent the liquid seal.

[0027] The upper and lower canisters can be coupled at sealed inferace such as a telescoping, threaded or flanged interface between the open bottom and open top of the upper and lower canisters respectively. [0028] In another broad aspect, a method of manufacturing a liquid metal battery comprises providing a housing comprising an upper electrically conductive anodic canister, and a lower cathodic canister and then introducing the battery chemistry including receiving a cathodic metal in the housing; receiving an electrolyte in the housing; receiving an anodic metal having a density lower than the cathodic metal in the housing; and sealingly coupling the anodic canister to the cathodic canister, wherein the interface between the anodic canister and the cathodic canister is disposed adjacent the electrolyte.

DESCRIPTION OF THE FIGURES

[0029] Figures 1 , 1A and 1 B are schematic views of a prior art molten salt battery generally, when charged and when discharged respectively;

[0030] Figure 2 is a schematic view of a prior art liquid metal battery;

[0031 ] Figure 3 is a cross-sectional view of one embodiment of a liquid metal battery disclosed herein;

[0032] Figure 4 is a cross-sectional view of another embodiment of a liquid metal battery shown in a charged state;

[0033] Figure 5 is a cross-sectional view of the liquid metal battery of Fig. 4 in a discharged state; [0034] Figure 6A is a close up cross-sectional view of an embodiment of the interface of a liquid metal battery having vacuum bottle-forms of canisters;

[0035] Figure 6B is a close up cross-sectional view of an embodiment of a flanged and ring seal connection for opposing top and bottom canisters;

[0036] Figure 7A is a cross-sectional view of a liquid metal battery in a further aspect, having a sump at the canister interface;

[0037] Figure 7B is a cross-sectional view of the liquid metal battery of Fig. 7A oriented at an incline;

[0038] Figure 8A is a cross-sectional view of a liquid metal battery in an aspect, having a liquid stilling baffle such as a honeycomb structure at about the interface;

[0039] Figure 8B is a cross-sectional view of the liquid metal battery shown in Fig. 8A, with liquid levels sloshing and stabilized by the honeycomb structure;

[0040] Figure 9 is a cross-sectional schematic view of a liquid metal battery in a further aspect, having an antennae dimple-type anode and in a ready-to-use state;

[0041 ] Figure 10 is a cross-sectional schematic view of the liquid metal battery shown in Fig. 9 in a storage state;

[0042] Figure 1 1 is a cross-sectional schematic view of another embodiment of a liquid metal battery, the canisters of which having a crucible-like inner surfaces; [0043] Figure 12 is a cross-sectional schematic view of another embodiment of a liquid metal battery, the canisters of which having a bevelled or slant wall inner surfaces;

[0044] Figure 13 is a cross-sectional schematic view of another embodiment of a liquid metal battery, having a lid therefor forming the anode;

[0045] Figure 14 is a cross-sectional schematic view of another embodiment of a liquid metal battery, the housing of which having a cubicle shape;

[0046] Figure 15 is a cross-sectional schematic view of another embodiment of a liquid metal battery having an anode canister with a larger diameter in its upper portion than in its lower portion;

[0047] Figures 16A, 16B and 16C are side, top and cross sectional views respectively of a closely fit upper and lower canisters in another embodiment; and

[0048] Figures 17A, 17B, 17C and 17D are steps in a methodology to assembly a liquid metal battery according to Figs. 16A-16C.

DETAILED DESCRIPTION

[0049] A liquid metal battery is provided wherein the interconnection or interface between a negative current collector and positive current collector is continually immersed in the cell electrolyte, the electro-chemical isolation occurring in the liquid salt environment of the cell electrolyte, rather than the highly corrosive anode vapour space.

[0050] With reference to an embodiment of the battery shown in Fig. 3, a liquid metal battery 300 comprises a housing 301 , the housing taking the form of a generally cylindrical container which aids in seal design. However, in other aspects, the housing could be cubicle or comprise any other practical 3-dimensional shape.

[0051 ] The housing 301 comprises an upper, anode canister 302 and a lower, cathode canister 304. The upper anode canister 302 is complementary and opposing to the lower cathode canister 304 for coupling together. The upper canister 302 is an upside down, cup-shaped container, having a closed top and an open bottom. The inner surface of the upper canister 302 acts as the negative terminal and houses an anodic metal 326. The lower canister 304 is an upside right, cup-shaped container, having an open top and a closed bottom. The inner surface of lower canister 304 acts as the positive terminal and houses a cathodic metal 322.

[0052] The open bottom of the upper canister 302 is fit to the open top of the lower canister 304. For example, as shown in Figs. 3 and 4, the open bottom of the upper canister 302 can fit into and within the open top of the lower canister 304, with the open bottom of the upper canister 302 top nested with the open top of lower canister 304. The periphery of the open bottom of the upper container 302 is then sealed, such as through an annular seal 31 1 , supported in the open top of the lower container 304. [0053] In other aspects, not shown, the open top of the bottom canister 304 can fit around the open bottom of the top canister 302, with the open bottom of the top canister nested within the open top of the bottom canister 304. The periphery of the open top of the lower container 304 is then sealed at the open bottom of the upper container 302.

[0054] In some aspects, as shown, the upper canister 302 can fit telescopically into the lower canister 304 or in other aspects, the lower canister 304 can fit telescopically into the upper canister 302.

[0055] For example, as shown in Fig. 3 the upper canister 302 is slidaby and telescopically fit into the lower canister 304 and in Fig. 9 the upper canister 902 is threadably and telescopically fit into the lower canister 904. As in the aspect shown in Fig. 9, in some aspects, the upper canister 902 and lower canister 904 can be in threadable engagement, with the upper canister 902 having threads around the outer circumference of its open bottom and the lower canister 904 having corresponding threads around the inner circumference of its open top.

[0056] It will be understood that other coupling and sealing mechanisms can be used to secure the upper canister 302 to the lower canister 304. For example, as shown in Fig. 6B, the open bottom of the upper canister 302 can sit flush with the open top of the lower canister at a flanged interface having annular flanges or circumferentially spaced flange tabs, such as three tabs. Fasteners at the flanged interface can form the closure mechanism. Ceramic, or otherwise non-conductive fasteners or bolts can aid in this regard. A high-temperature gasket, such as a sheet gasket, or ring gaskets such as Therm iculite sheet or spiral wound gaskets (From Flexitallic Canada, Edmonton, Alberta) can then be applied to achieve a seal at the interface. Ring Gaskets or O-Rings are typically fit to annular grooves about the flanged interface. In some aspects, an O-ring can be used for both pressure containment and insulation. As suitable O-Ring is a spring energized O-ring seal. In some other aspects, polymer sealants can be used. In some aspects, a Copaltite™ sealant can be used. In other aspects, Deacon 8875™ sealant can be used. In some aspects, Rutland Refractory Cement #610™ can be used. Generally, the sealant can withstand high pressures and temperatures up to and including 525°C.

[0057] Referring again to Fig. 3, the level of the metal and electrolyte and the environment of the upper canister 302 is understood to be the most difficult to manage during charging, discharge and during the change in state from liquid to solid. Making the upper canister 302 itself electrically conductive can avoid known difficulties with mechanical electrode failure and sealing failures, as there does not need to be an electrode penetrating the upper canister 302. Accordingly, in some aspects, at least the upper canister 302 is itself electrically conductive and forms the negative electrode. The conductive material forming the inner surface of the upper canister 302 is also generally capable of containment at elevated temperatures typical for liquid metal batteries, and in some cases, could be stainless steel. In some aspects, the upper canister 302 is made out of a conductive material, and the lower canister 304 is also made out of a conductive material. In some additional aspects, and at additional cost, conductivity between the liquid metals 322, 326 and the conductive canisters 302, 304 can be aided with a platinum coating 315, 317 or interface, as described in more detail below.

[0058] The outer surfaces of the canisters 302, 304 can be suitably-shaped, such as cylindrically-shaped or square-shaped with sharp or rounded edges. The inner surfaces of the canisters 302, 304 can also be suitably-shaped so long as they form a cavity within the respective canister 302, 304. For example, the cavity formed by the inner surfaces of the canisters 302, 304 could be generally cylindrical in shape such as is shown in Fig. 3, or the canisters 402, 404 could provide for a rounded-bowl shape or crucible such as shown in Fig. 4 and related embodiments.

[0059] The upper and lower canisters 302, 304, respectively, are liquidly sealably and electrically non-conductively coupled using suitable means such as, for example, a non-conductive seal between them. The connection between the canisters 302, 304 can be sealed together such that liquid cannot pass across the connection between the canisters 302, 304.

[0060] For this purpose, in the aspects shown in Figs. 1 -8B, a sealing interface 318 is provided. For example, the sealing interface 318 comprises annular seal ring 31 1 and a compression ring 314 for axially loading the seal 31 1 .

[0061 ] The first upper conductive canister 302 can fit telescopically to a second conductive lower canister 304. In the embodiments shown, the canisters 302, 304 have a circular cross-section, at least at the seal area, which aids in structure, annular seal design and assembly. The upper and lower canisters 302, 304 are sealably coupled by annular seal ring 31 1 or packing gland such as a graphite seal ring. The annular seal ring 31 1 is compressed axially using the compression ring 314 for radial loading. The compression ring 314 is axially compressed using threaded fasteners 314F. The seal ring 31 1 can be an electrical insulator such as a graphite packing ring, although other non-conductive seals can be provided, recalling the high temperature environment, such other seals including coated, threaded sealing interfaces and labyrinth seals, combinations thereof and the like both.

[0062] In the aspect shown in Fig. 9, the upper and lower canisters 902, 904 are coupled through the use of threading 914 and a seal, the canisters sealed together with sealant 908 therebetween. Other suitable means of coupling and sealing upper and lower canisters 302, 304 together could be used as well. The seal can substantially lock the two canisters 302,304 together or enable a sliding/sealing interface therebetween.

[0063] The upper and lower canisters 302, 304 as well as the coupling and sealing mechanisms therebetween can be capable of containment of fluids at the elevated temperatures typically required for liquid metal cell operations. While the coupling and sealing mechanisms can in some aspects provide for a fluidic seal, in other aspects, the seal can be a liquid seal only, while some gases could pass therethrough. Some gas permeability can be acceptable, as the seal is disposed adjacent the solid or liquid electrolyte salt layer 324, and not in contact with a noxious gaseous internal space. [0064] The lower canister 304 of the housing 301 , or at least a portion thereof, comprises an electrically conductive wall, such as an electrically conductive bottom wall 310, forming the cathode or positive terminal. The upper canister 302 of the housing 301 , or at least a portion thereof, comprises an electrically conductive wall, such as an electrically conductive top wall 312, forming the anode or negative terminal.

[0065] To complete a liquid metal battery 300, the housing 301 receives therein a first metal 322 adjacent the bottom wall 310 of the housing 301 , a salt 324 as electrolyte above the first metal 322, and a second metal 326 above the electrolyte 324. The electrically conductive bottom wall 310 is in electrical contact with the first metal 322, forming a cathode. The electrically conductive top wall 312 is in electrical contact with the second metal 326, forming an anode. Various means can be employed for filling the housing, including cold assembly for ease of handling the solid metals and electrolytes, or molten filling through a temporary port in the top canister.

[0066] The second metal 326 has a density lower than that of the first metal 322. As can be seen in the aspect shown in Figs. 4, 9 and 1 1 -15, a vacuum head space 928, or so-called vapour space, can be reserved in an upper portion of the housing 401 above the second metal 326 for accommodating highly corrosive and reactive off-gas.

[0067] As those skilled in the art will appreciate, the first and second metals 322 and 326 are in a liquefied state in operation at a higher temperature. For example, both metals 322, 326 can be in a liquid state at any temperature higher than the room temperature, and may be in a solidified state in storage at a lower temperature, for example, at or below room temperature. However, in some aspects, the melting point of metals 322, 326 can be higher or closer to the typical operating temperatures of the battery. Similarly, the liquid salt electrolyte 324 is in a molten state in operation at the higher temperature and may be in a solidified state in storage at the lower temperature. In some aspects, the salt electrolyte could be LiCI-Lil and in other aspects could be lithium iodide Lil or lithium chloride LiCI alone.

[0068] The liquid metal components 322, 326 can be selected from the periodic table separated into lighter and heavier and anodic and cathodic components. Suitable anode and cathode metals can be selected. Generally, in the layout of the periodic table of elements, the strong electropositive (donor) metals are low density, and the strong electronegative (acceptor) metals are high density. Thus, negative electrode metal material candidates forming the upper, negative anode terminal are selected from the list comprising Lithium (Li), Sodium (Na), Magnesium (Mg), Potassium (K), Calcium (Ca), Rubidium (Rb), Strontium (Sr), Caesium (Cs), and Barium (Ba).

[0069] The heavier, positive metal material candidates forming the lower, positive cathode terminal are selected from the list comprising Zinc (Zn), Gallium (Ga), Cadmium (Cd), Indium (In), Tin (Sn), Antimony (Sb), Technetium (Te), Mercury (Hg), Thallium (Tl), Lead (Pb), and Bismuth (Bi). The cathode metal material candidates are higher density than the anode metal material candidates, so when they are mixed together, the anode and cathode liquid metal components 322, 326 will naturally separate with the cathode metal 322 layer on the bottom of the cell. By choosing among the options, designers of the liquid metal battery 300 can optimize cost, material availability, operating temperature, cell voltage, or other characteristics to suit a particular application. Whichever combination of liquid metal components 322, 326 are used, all the liquid metal components 322, 326 and salt 324 are liquid at practical operating temperatures. In an aspect, a suitable combination comprises lithium (Li) used as the negative electrode metal material 326, and lead (Pb) used as the positive electrode metal material 322. Other combinations are available, depending on factors such as economics and efficiency, as known to those in the art. In some aspects, the combination of anodic and cathodic metals can be selected based on various materials with lower melting points. For example, the cathode metal 322 could be antimony, but could instead be lead, tin, bismuth, and alloys of similar metals. The anode metal 326 could be magnesium, but in other aspects could be sodium, lithium, and alloys of magnesium with such metals as calcium.

[0070] Referring now to Figs. 4 and 5, in an aspect, in the charged state shown in Fig. 4, the upper anode metal 326 can be pure magnesium (Mg) and the bottom cathode metal 322 can be pure antimony Sb.

[0071 ] During discharge, Mg ions move from the anode through the electrolyte 324 to the cathode, the cathode becoming a molten mixture of Mg-Sb. As this happens, the volume of the bottom liquid 322 increases, the salt layer 324 being displaced upward, and the volume of the upper metal 326 decreases. The discharged state is shown in Fig. 5, with the cathode metal 322 increasing in volume to become a thicker layer during discharge. Hence, the salt layer 324 is displaced upward while the cell 400 is discharging and moves downward while the cell 400 is charging during the ionic exchange.

[0072] The movement of this salt layer 324 can pose a challenge for containment seals. Further, as the battery 400 transitions from liquid-to-liquid ionic exchange operation at high temperature to a solid, inactive state, or offline state such as for storage and shipment, the metals 322, 326 contract, posing containment challenges as the liquid contracts to a solid and the structure or housing 401 supports this solid rather than liquid. In reverse, during re-activation, as the solid metals 322, 326 heat up, they expand, also placing significant loading on the structure of the containment 401 and related components.

[0073] The various sealing interfaces 318 shown in Figs. 1 -8B can aid in this regard. Such sealing interface 318 remains between the upper and lower canisters 302, 304 and located in or adjacent the salt layer 324. This minimizes leaking of the salt layer 324 out of the housing 301.

[0074] The interface between the conducting inner surfaces of the canisters 302, 304 is also electrically isolated. The interface can be isolated using a discrete insulator located between the interface, an insulating coating on one or both adjacent surfaces of the interface, or both. Further, an electrically insulating coating could also serve as an anti-corrosive surface in the difficult environment of the hot electrolyte 324. [0075] In the aspects shown in Figs. 1 -8B, the upper canister 302 is itself electrically conductive and forms the negative electrode. While the environment for the lower electrode is less harsh, an electrically conductive containment can also be used as the lower liquid metal vessel 304. Where an electrically-conductive material is used to form either or both of the negative and positive electrode canisters 302, 304, electrical isolation is provided between the upper conductive canister 302 and the intermediate salt layer 324 and the lower conductive canister 304 and the intermediate salt layer 324, as the case may be.

[0076] In the aspects shown, such insulation is provided by means of a ceramic insulation 313 coated to the upper and/or lower canister 302, 304 at locations where the salt electrolyte 324 is likely to make contact, for preventing short circuiting between the terminals through the electrolyte 324. As in this embodiment, the open bottom of the upper canister 302 is fit to the open top of the lower canister 304 and the periphery or rim of the open bottom of the upper conductive container 302 is sealed at the open top of the lower canister 304. The rim, inner wall and outer wall are rendered insulated to electrically isolate the portions of the upper canister 302 exposed to the salt 324. As shown, a coating of insulating material 313, such as a ceramic coating, is provided part way up the outer wall, around the rim, and part way up the inner wall.

[0077] Electrical contact between other portions not protected by the insulating material 313 can be enhanced in some aspects. Electrical contact between the electrically conductive bottom wall 310 and the first metal 322 can be enhanced with a platinum coating 315 for at least a portion of the inner walls not protected by the insulated portion 313. Electrical contact between the electrically conductive top wall 312 and the second metal 326 can similarly be enhanced with a platinum coating 317 for at least a portion of the inner walls not protected by the insulated portion 313.

[0078] As can be understood by reference to Fig. 3, a portion of the upper canister 302 extends into the salt electrolyte 324. At least a lower portion of an inner wall of the upper canister 302 is insulated, such as through the use of ceramic coating 313, so that the salt 324 is not in electrical contact with the conductive material of the upper canister 302. In some aspects, the ceramic coating 313 can be 0.008" to 0.010" applied to the anode canister 302 wall on both the inside and the outside to ensure electrical isolation. In some aspects, the ceramic coating 313 can be polished smooth on the outside wall of the anode canister 302. The ceramic coating 313 could have sufficient electrical integrity to withstand heating to at least 525°C and in some cases could be an aluminum oxide compound. In some aspects, the ceramic coating 313 can comprise an alumina-titania insulation.

[0079] In some aspects, the lower canister 304 can also be formed out of conductive material capable of containment at the elevated temperatures. In the aspect shown in Fig. 3, a portion of the conductive lower canister 304 extends into the salt electrolyte 324 and only an upper portion of an inner wall of the lower canister 304 is insulated, such as with the ceramic coating 313, so that the salt 324 is not in electrical contact with the conductive material of the lower canister 304. It will be understood, however, that in some aspects, the upper canister 302 can be insulated with a ceramic coating 313, while the lower canister 304 is not insulated with a ceramic coating 313.

[0080] In an embodiment, the anode and cathode containers 302, 304 are formed of 304 Stainless Steel (SS) while maintaining mechanical integrity and electrical isolation therebetween. In other aspects, the containers 302, 304 could be formed of 347 Stainless Steel (SS).

[0081 ] The rim of the anode canister 302 is located within the fluidized electrolyte region 324, within a vertical range that is always flooded with liquefied salt 324. The salt layer 324 migrates up and down with electrical charge. Thus a double containment mechanism is provided.

[0082] Accordingly, as the liquid metal components 326, 322 solidify and liquefy, the liquid metals 326, 322 remain in contact with the conductive inner walls of the upper and lower canisters 302, 304, respectively. As mentioned above, electrical contact can be enhanced with a platinum coating 317, 315 for at least a portion of the inner walls not protected by the insulated portions 313.

[0083] As discussed above, a material seal 318 is provided between the upper canister 302 and the lower canister 304 at the salt layer 324, and each of which are electrically isolated from each other. The open bottom of the upper canister 302 can be fit either telescopically into the lower canister 304, the upper canister 302 having a smaller cross-sectional area or diameter than that of the lower canister 304, or fit around the open top of the lower canister 304, the upper canister 302 having a larger cross-sectional area. In either embodiment, an annular seal 318 is formed about the telescopic interface. In some aspects, there is sufficient space between the inner diameter or surface of the lower canister 304 and the outer diameter of the upper canister 302, or vice versa, to allow for a snug fit. The amount of space therebetween can be determined by the space required during thermal cycles and at least ambient temperatures of 525°C to ensure that a seal is maintained at all times, but that the ceramic coating 313 or insulated portions are not crushed or damaged during the thermal cycles, at which time the containment unit 301 will be expanding and contracting, often at elevated temperatures.

[0084] In testing, Applicant thermally cycled LMB CU's through a wide range of temperatures, with and without battery chemistry stored therein. In one test, two empty CUs of the form set forth in Fig. 4, were cycled from room temperature 0.5°C/min up to 400°C. Further testing was conducted on Pb-Sb-filled CU's sealed together with Deacon 770-P. Further the containers were cycled from ambient to increasing temperatures of 400, 425, 450, 475, and 525°C. Further a repeat of the tests included use of the Pb-Sb cathode alloy, a LiCI-Lil salt/electrolyte, and the lithium anode suitable to verify mechanical integrity, the seal, electrical integrity, and ability to withstand phase changes.

[0085] As may be best shown in Fig. 6A, the seal area interface 318 can be formed with open areas to avoid trapped liquid metal and possible damage during metal solidification during shutdown. The open bottom of the upper canister 302 and the open top of the lower canister 304 are sized to permit a packing to fit operatively therebetween. To minimize a pinch point therebetween, a flared opening 520 can be provided at the open end of the outer canister, being the lower canister 304 in this instance, and provide a larger area therebetween. This flared opening 520 can provide relief for trapped metals and can minimize thermal stress.

[0086] With reference to Fig. 6B, the seal area interface 318 comprises a flanged interface 390 having upper and lower annular flanges 392, 394 and seal 31 1.

[0087] Referring again to Figs. 4 and 5, at least the upper canister 402 can have inner walls that are tapered or are crucible-shaped, forming a draft therein. In this way, the upper canister 402 can be less subject to structural damage during contracting metal solidification for storage and shipment and thermal expansion during re-heating to operations, with the maximal force occurring before re- liquefaction. The draft formed therein can permit a radially expanding solid some axial (up or down as the context permits) relief as it moves along the diverging walls. The lower canister 404, having upwardly diverging walls, can enable upward growth and movement of the cathodic metal 322 upon heating. The upper canister 402 having downwardly diverging walls can result in the anodic metal 326 relieving downwardly, or moving the canister housing 401 upwardly in the case of a telescopic joint and seal interface 318 allowing relative axial movement. Alternatively, a metal zone of an upper canister can have an upwardly diverging wall for similar benefits as in the lower canister 404. [0088] In some aspects, such as that shown in Fig. 6A, the canisters 602, 604 can themselves be vacuum flasks for thermal efficiency. Thermal input, or the charging cycle, can provide the thermal energy for maintaining the 500°C to 600°C environment for liquefaction of the reactive components. Vacuum flask or bottles 642, 644 can be provided in the canisters 602, 604, respectively, to increase thermal efficiency by insulating against heat loss to the outside cell environment. The materials forming the canisters 302, 602, 304, 604 and the seal 318 therebetween can generally withstand 500°C-600°C normal operating temperatures. In some aspects, the canisters 302, 602, 304, 604 and the seal 318 therebetween can withstand potential 0°C-700°C upset condition swings.

[0089] Thermals cycles can be controlled by minimising the number of temperature cycles from manufacture to installation and thereafter from normal charge-discharge operation and ultimately including to emergency or planned shutdowns. In a method of manufacturing a molten salt battery 300, the electrode metals 322, 326 plus the electrolyte salt 324 can be added to a container such as a steel container that can withstand high heat, and the container can be heated to the specified operating temperature. The materials 322, 324, 326 will melt into neat liquid layers to form the electrodes and electrolyte 324. In some aspects, the process can be automated to aggregate many cells 300 into a large-format battery including to power electronics.

[0090] The manufacturing process can be performed in a vacuum under high temperature conditions. To avoid contamination, the battery cell 300 can be assembled in an inert gas environment at ambient temperatures, then subsequently liquefy the "anode-electrolyte-cathode" materials 322, 324, 326 within the completed cell housing 301 . The materials of construction can be chosen to manage, minimize or eliminate differential thermal expansion at interfaces. In this regard, and in operation, thermal losses can be minimized through cell and environment design.

[0091 ] In one embodiment, assembly of the battery 300 could include assembling the upper and lower canisters 302, 304, the upper canister 302 having a temporary top access. The liquid metal 322, 326 and electrolyte 324 can be added through the top access and the top access can then be sealed. All of the above can be conducted in an inert gas environment, such as argon or nitrogen, to exclude oxygen and other contaminants. To minimize equilibrium issues, one could add the liquid cathodic metal 322, then the salt 324, and lastly the liquid anodic metal 326.

[0092] Alternatively, and before assembly, the anode and cathode canisters 302, 304 can be liquid filled separately with their respective metals and cooled to solidify. Then during assembly of the upper and lower canisters 302, 304, the electrolyte space formed between the anodes and cathodes is topped up with solid electrolyte (salt) 324, all within an inert gas environment. The system can then be heated to activate the cell 300 into operation. Heating could be through external means or through a start-up form of charging cycle.

[0093] To aid in electrical conduction between the anode and cathode materials, the conductive portion of the inside of the canisters can be coated with a platinum type conductor 315, 317, as described above. Further, limitations on the material of manufacture of the canisters 302, 304 can be alleviated somewhat through the use of a highly conductive platinum layer on an otherwise less desirable canister material.

[0094] The assembled and completed battery cell 300 could then be shipped to site. The battery cell 300 could be safely and conveniently shipped as an individual cell 300, or in a bank of cells 300 for eventual assembly of a multi-cell battery on site.

[0095] The upper and lower canisters 302, 304 could be stamped, with information detailing such things as the materials from which they are made, the stamping avoiding significant metallurgical changes as occur in welded or brazed assembly. The stamped canisters 302, 304 can then be modified with one or more of platinum enhanced conductive surfaces and insulating surfaces such as ceramic coatings 313.

[0096] In some aspects, the elimination of protuberances at the anode can facilitate stacking for ease of commercial cell designs accommodating stacking multiple cells 300 in a battery stack while keeping the individual heights as small as possible, and while noting that deep electrolyte layers 324 reduce ionic transfer efficiencies.

[0097] Again referring to Fig. 6A, in some aspects, the canisters 602, 604 can have a vacuum bottle-like design for one or both of the upper anode and lower cathode canisters 602, 604. The option to form the structure of the canisters 602, 604 with a hollow section, having a vacuum 642, 644 therein, is shown in dotted lines. Alternatively, or in combination, one can operate the assembled canisters 602, 604 in electrical vaults at partial vacuum to reduce heat transfer coefficient between cells and environment

[0098] Referring again to Fig. 3, in operation, full scale thermal cycles would be minimal, once the integrated battery 300, multiple cells in series, parallel, or both, have been put into service. The battery 300's off-line tolerance, understanding that a shutdown can result in solidification of the normally liquid metal components 322, 326, enables cooling of the liquid metals 322, 326 including to the point of solidification. This can permit maintenance personnel to execute repair work at near ambient temperature and pressure and then bring the unit back into service without battery operative or structural failure.

[0099] In some embodiments, the cells can be configured and rendered useful for mobile application, subject to dynamic movement while operating. For example, some liquid metal batteries disclosed herein may be used in mobile applications such as in vehicles. In these embodiments, the battery can comprise additional components for adapting to the sloshing environment of the cell for ensuring safety.

[0100] As an example, shown in Fig. 7A and 7B, a sump 750 can be provided. When fabricating the lower cathode canister 304, a sump 750 can be created around the joint between the two canisters 302, 304. This sump 750 can trap electrolyte 324 in such a manner that it ensures that the joint is always in contact with electrolyte 324 when the liquid levels change due to the change of motion and/or orientation of the cell 700. Fig. 7B shows the battery installed in a car (not shown) and the liquid levels when the car is parked on a hill. As can be seen, even when the battery 700 is placed at an incline, the joint maintains contact with the electrolyte 324. As may be further noted, the ceramic coating 313 which extends above and below the typical operating charged and discharged areas where the electrolyte 324 can typically be found when the cell 700 is on even ground can ensure that the salt 324 is not in electrical contact with the conductive material of the lower canister 304 or the upper canister 302, even when the cell 700 is at an incline.

[0101 ] In another embodiment as shown in Figs. 8A and 8B, a liquid stabilizer 860, such as a ceramic honeycomb structure, can be received in the electrolyte layer 324 for reducing motion dynamics. Fig. 8B shows the battery at an incline, for example, when installed in a car (not shown), or when the liquid levels are uneven when the battery 800 is in a sloshing environment. In some aspects, the liquid stabilizer 860, such as the ceramic honeycomb structure, may be alternatively received in the anode layer, extending downward into the electrolyte layer 324. However, this requires the anode metal 326 be maintained in liquid form as solidified anode metal 326 may destroy the honeycomb 860. Similarly, the ceramic honeycomb structure 860 may be alternatively received in the cathode layer, extending upward into the electrolyte layer 324. However, this requires the cathode metal 322 be maintained in liquid form as solidified cathode metal 322 may destroy the honeycomb 860. [0102] Various other embodiments may be provided to reduce or manage liquid movement within the cells. In an embodiment, a plate having one or more orifices may be positioned or float in the electrolyte 324 for stabilizing the liquids. In another embodiment, a viscous or gel-like layer can positioned between the anode layer and the electrolyte layer 324, and/or between the electrolyte layer 324 and the cathode layer for reducing liquid movement. The gel-like layer may act like a membrane allowing the anode/cathode metal 322, 326, as the case may be, to be in direct contact with the electrolyte layer 324. Alternatively, the gel-like layer can also be an electrolyte layer. In some embodiments, the entire electrolyte layer 324 can be viscous or gel-like. In some other embodiments, a ceramic mesh can be positioned and floating within the electrolyte layer 324 for reducing liquid movement. In this embodiment, the liquid electrolyte 324 is entrained within a matrix of the ceramic mesh, which inhibits localized fluid movement in a manner that traps the liquid electrolyte 324 within an isolating sandwich between the liquid anode 326 and cathode layers 322 of the battery. The ceramic mesh may be a sheet-like mesh. For example, the mesh can be a ceramic screen with a density that floats on top of the liquid cathode layer 322 below the electrolyte 324. Using such a physical mesh or screen within the electrolyte layer 324 can benefit from the phase change characteristic of salt to expand as it transitions from a liquid to a solid. This could reduce mechanical stresses on the sheet-like mesh during this phase change. The ceramic mesh can also provide a mechanical certainty to the application of the battery in sloshing or moving environments. [0103] Referring now to Figs. 9 and 10, at least a portion of an electrically conductive top wall 912 extends generally downwardly forming an "antennae dimple" 970 such that the outer surface of the antennae dimple 970 forms a recess 970A, and the inner surface thereof forms a generally downwardly extending protrusion acting as an anode collector. The electrically conductive wall 912 of the upper canister 902 may be formed and/or manufactured by a sheet metal. The antennae dimple 970 may be formed by stamping, giving rise to fast and low-cost manufacturing. The height of the antennae dimple or anode collector 970 is such that, in operation, the lower end of the anode collector 970 is in electrical contact with, e.g., extending into, the liquefied anode metal 326 during operation. Of course, other portions of the electrically conductive wall 912 may be also in electrical contact with the anode metal 326 during operation.

[0104] Having an antennae dimple 970 in the top of the anode canister 902 can eliminate or reduce the risk of the anode collector losing contact with the liquefied anodic metal 326. Having an antennae dimple 970 can also allow the extension of the ceramic wall coating 313 to facilitate minimizing the electrolyte layer 324 thickness. Generally, the uncharged state of the battery cell 900 only has two phases, i.e., the electrolyte 324 at the top and the charged anode/cathode alloy 322 at the bottom. Therefore, the battery design disclosed herein can allow simplified manufacturing and assembly by initially melting the anode/cathode alloy 322 for fluid delivery into the bottom of the cathode canister 904 and subsequently adding liquid salt 324 by filling the anode canister 902 with salt 324. [0105] Moreover, commercial battery cell designs need to adapt to the requirement of stacking multiple cells while keeping the individual heights as small as possible. Too much electrolyte 324 reduces battery efficiencies. An antennae dimple 970 in the anode canister 902 can solve the issues related to the vapour space 928 and can ensure the anode collector is always in contact with the liquefied anodic metal 326 in operation. The antennae dimple 970 can eliminate any attachment mechanisms and/or electrical mechanical considerations.

[0106] Fig. 10 shows a storage configuration of the battery 900 suitable for storage and shipment. As shown, a metal alloy 322 comprising the anode metal 326 along with the cathode metal 322, which is in a solid state at room temperature, is placed in the housing 901 . The salt 324 in a solid state can then be placed in the housing 901 on top of the alloy 322. The space in the housing 901 above the salt 324 can be made a vacuum. The battery 900 is thus in a discharged state. As both the alloy 322 and salt 324 are in solid states, and the battery 900 is electrically discharged, they can be safely stored or shipped.

[0107] In use, the battery 900 in the configuration or state of Fig. 10 is heated to an operational temperature to liquefy the alloy 322 and the salt 324. The first and second metals 322 and 326 and the salt 324 change phase from solid to liquid when the battery 900 is turning from storage (cold) to operation (hot). After liquefaction, the battery 900 is connected to an electrical power source for charging. The alloy 322 is separated to an upper, liquid anode metal layer 326 and a lower, liquid cathode metal layer 322 separated by the molten salt layer 324, as shown in Fig. 9. The battery 900 is then ready to power electrical devices.

[0108] During the phase change from solid to liquid, the first and second metals 322 and 326 expand. The salt electrolyte 324 shrinks, while the head space 928 is a vacuum. There will be a volumetric balance between the available voidage created within the shrinking electrolyte zone 324 and available head space 928 and the expanding anode and cathode metals 322, 326. During this time, there are also forces exerted against the side walls of the upper and lower canisters 902 and 904. In the case of cylindrical canister walls, the radial forces must be resisted entirely by the structure 901 . In another embodiment, the canisters 902, 904 can be non- cylindrical, to aid in redirecting radial forces upward. Such forces can include the radial expansion of the solid metal until such time as it liquefies.

[0109] As an example and as shown in Fig. 1 1 , the canisters 1002, 1004, or at least the inner surfaces thereof, can be crucible-like, having a surface of revolution formed by an ellipse. Accordingly, the radial forces created against the side walls of the lower canister 1004, particularly during the heating from the solid to liquid state, are reduced, a force vector being directed upwards via the angled crucible's outer wall, aiding the solid form of the metal 322 to move upwards. Anode metal 326 expansion can be absorbed by the head space 928 and further, the anode canister 1002 walls can also be formed in a crucible shape to direct some of the expansion forces downward. [01 10] In some embodiments, the recess 970A of the antennae dimple 970 may be used for accommodating suitable electrical and/or mechanical component(s) such as an electrical terminal and wiring for outputting electrical power. As another example, a controller component may be sealed in the recess 970A in a heat insulated manner for controlling the operation of the battery 900. Accommodating suitable electrical and/or mechanical component(s) in the recess 970A leverages the available space, and allows a flat top suitable for stacking.

[01 1 1 ] In some embodiments, the anode and cathode canisters 902 and 904 are formed of 304 Stainless Steel (SS) while maintaining mechanical integrity and electrical isolation therebetween. In another embodiment, the anode and cathode canisters 902 and 904 are formed of Stainless Steel (SS) such as 304 Stainless Steel Steel or 347 Stainless Steel, with a platinum coating. In yet another embodiment, the anode and cathode canisters 902 and 904 are formed of other suitable metals with platinum coating.

[01 12] In an alternative embodiment as shown in Fig. 12, at least an upper portion of the side wall 932 of the anode canister 902 is a beveled, inclined or slant wall extending generally upwardly and inwardly such that the anode canister 902 has smaller diameter in the upper portion thereof than that in its lower portion. Similarly, at least a lower portion of the side wall 934 of the cathode canister 904 is a slant wall extending generally downwardly and inwardly such that the cathode canister 904 has smaller diameter in the lower portion thereof than that in its upper portion. [01 13] In an alternative embodiment as shown in Fig. 13, the anode canister 902 is a lid coupled to the cathode canister 904. A seal 942 is sandwiched between the anode lid 902 and the cathode canister 904 for liquid sealing and electrical isolation therebetween.

[01 14] Generally, the antennae dimple 970 may have a generally conical shape for ease of manufacturing. However, alternatively, the antennae dimple 970 may have another suitable shape, such as a generally cylindrical shape.

[01 15] In an alternative embodiment as shown in Fig. 14, the housing 1401 has a cubical shape. Also, the antennae dimple 1470 is a downwardly extending valley horizontally extending from a side wall to an opposite side wall, the underside or ridge of which is electrically conductive. Compared to the embodiments shown Figs. 9 through 12, the ridge-like antennae dimple 1470 of Fig. 14 may prove be easier to manufacture than the recess-shaped antennae dimple 970 in Figs. 9 through 12. However, the ridge-like antennae dimple 1470 of Fig. 14 may have a disadvantage in that the ridge-like antennae dimple 1470 can trap the off-gas in two fluidly unconnected vacuum spaces 1428A and 1428B, and impedes off-gas travelling.

[01 16] Of course, the housing of a cell having an antennae dimple 970 may be other suitable shapes in various embodiments, and the antennae dimple may be a recess, a valley/ridge or other suitable downwardly extending shape. For example, in the aspect shown in Fig. 15, at least a lower portion of the upper canister 1502 also has a slant side wall 1544 extending generally upwardly and outwardly such that the anode canister 1502 has larger diameter in the upper portion thereof than that in its lower portion.

[01 17] In some aspects, the antennae dimple 970 is manufactured using a stamping technique. Compared to other manufacturing methods, stamping the antennae dimple 970 can cause no or less metal (e.g., steel) degradation.

[01 18] With reference to Figs. 16A through 17D, an alternative method of manufacture is provided in which the upper and lower canisters are friction fit or shrink-fit to form a liquid seal. The interface also forms the electrical isolation between the two otherwise electrically conductive inner surfaces. The upper and lower canisters and be machined, rolled or simply stamped. The anodic can be formed with the dimple integral therewith.

[01 19] Accordingly, in an embodiment, and as shown in Figs 16A through 16C, and Figs. 17A - 17D, a liquid metal battery housing is provided comprising an upper electrically conductive anodic canister, and a lower cathodic canister. The cathodic metal is received in the housing, the electrolyte is received in the housing and the anodic metal is received in the housing. The canisters are coupled and sealed together.

[0120] The anode canister is a cup-like structure having an open bottom and cylindrical outer walls. The cathode canister is a cup-like structure having an open top and cylindrical inner walls. The anode canister outer walls can be sealingly fit to the inside walls of the cathode cylinder by friction or shrink fit. The seal need only a liquid seal, not a gas seal.

[0121 ] At least the outside walls of the anode canister can be treated to provide the electrical isolation. The anode canister lip and axially extending walls can be treated with a metallic bond and a ceramic top coat, the ceramic top coat providing electrical isolation.

[0122] In this embodiment, as the electrical isolation also forms the seal, the interface of the seal need not be protectively aligned with the electrolyte.

[0123] Figures 17A, 17B, 17C and 17D are steps in a methodology to assembly a liquid metal battery including, in Fig. 17A inverting the anodic canister. In Fig. 17B, the anodic material, the electrolyte and the cathode material are placed in the anodic canister. In Fig. 17C, the inverted cathodic canister is inserted over the anodic canister. In Fig. 17D, the cathodic canister is sealably coupled to the anodic canister and the cathodic material liquefies the fill the voids. Back to Fig. 16C, the assembly can be righted, or inverted back to their normal orientations for use.

[0124] In more detail, in one approach, the anode canister is inverted, with the open bottom oriented upwardly for ease of receiving the anodic, the electrolyte and the cathodic chemistry. Once introduced, the cathode canister is coupled to the anode canister and the assembly righted for thermal activation and use.

[0125] In greater detail, in this embodiment of the methodology for assembly, one first and inverts the anode canister and purge the housing with an inert gas, such as argon, or helium. Pour a liquefied anodic material into the bottom of the canister and allow it to cool. One can then insert a pre-formed puck of electrolyte material into the canister above the anodic material. Preferably one inserts the puck of electrolyte material whilst the anodic material is still liquid or semi-solid form so as to minimize possible voids of trapped gas. One repeats the above steps with a formed puck of cathode material.

[0126] Formed pucks are sized to fit the inner diameter of the anodic canister.

[0127] The height of the puck of cathode material is such that it projects above the open bottom of the lip of the anodic canister's open bottom. The projecting material has a volume sufficient to fill the otherwise void space remaining between the soon to be coupled anode and cathode canisters.

[0128] As stated above the cathode canister can be heated to temporarily expand the wall diameter for ease of fitting over the handle canister balls. Further, when the two canisters are coupled together a small portion of the cathode material can come into contact with the heated cathodic canister. The cathode material will melt allowing the cathodic canister to land or fully couple onto the anode canister's lip. while coupling the anode and cathode canisters, gas can escape along the cylindrical interface, perhaps enhanced by an inclined profile adjacent the open bottom of the anode canister forming an increase annular gap. The cathode material melts and flows into the annular gap between the two canisters. Capillary effect will draw the liquid cathode material into the annular space and any void as it cools forming a seal in the cold cell storage state [0129] The assembly can be inverted to an upright position and heated to thermally activate the liquid metal battery.

[0130] The final volume of the battery chemistry, in particular the installed height of the cathode material, can ensure that the void space between the coupling of the two canisters is fully consumed leaving no moisture or air trapped within the assembled cell

[0131 ] The assembly can also be conducted in an inert environment or in or under a vacuum.

[0132] Thus the methodology herein further comprises electrically isolating the upper anodic canister along an interface between the anodic canister and the electrolyte. The upper anodic canister has an open bottom and the lower cathodic canister has an open top, further comprising inverting the upper anodic canister with open bottom oriented upwards; and wherein the receiving the anodic metal in the housing comprises introducing liquefied anodic metal through the open bottom; the receiving the electrolyte in the housing comprises introducing electrolyte through the open bottom on top of the anodic metal; the receiving the cathodic metal in the housing comprises introducing cathodic metal through the open bottom on top of the electrolyte; and inverting the lower cathodic canister and sealably coupling the open top with the open bottom of the inverted upper anodic canister.

[0133] In an embodiment, before introducing the cathodic metal, one can cooling the anodic metal and electrolyte in the anodic canister and a solid plug of cathodic metal is formed and inserted through the upwardly facing open bottom to sit on top of the solidified electrolyte, the cathodic metal protruding from the open top. Thereafter, one inverts the sealably-coupled, upper anodic canister and lower cathodic canisters before thermal activation.

[0134] In some aspects, other commercial applications are rendered practical including the ability to construct, transport and install the cells while in a solid off-line form. In some aspects, a cell can utilize vacuum containers and a further vacuum vault about the cell itself to conserve energy. An optional vacuum vault can also enable use for injection of cooling fluid flow for deliberate shutdown.

[0135] The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous changes and modifications will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all such suitable changes or modifications in structure or operation which may be resorted to are intended to fall within the scope of the claimed invention.

Claims

1 . A liquid metal battery comprising:

an upper canister housing having an electrically conductive inner surface;

a lower canister housing an electrically conductive inner surface;

electrical isolation between the electrically conductive inner surfaces of the upper and lower canisters; and

a liquid seal coupling the upper and lower canisters, wherein the coupled upper and lower canisters house an upper anodic metal and a lower cathodic metal respectively, and housing an electrolyte layer disposed between the anodic metal and cathodic metal, all of which are liquefied in operation,

2. The liquid metal battery of claim 1 wherein electrical isolation forms the liquid seal.

3. The liquid metal battery of claim 1 wherein the electrolyte layer is arranged adjacent the liquid seal.

4. The liquid metal battery of claim 1 wherein electrical isolation is provided at the interface between the upper conductive canister and the electrolyte layer.

5. The liquid metal battery of claim 2 wherein the electrical isolation comprises a ceramic electrical insulation coated on at least a portion of the upper canister.

6. The liquid metal battery of claim 3 wherein the ceramic insulation comprises an alumina-titania insulation.

7. The liquid metal battery of claim 1 wherein the anodic metal is selected from the group consisting of: Lithium (Li), Sodium (Na), Magnesium (Mg), Potassium (K), Calcium (Ca), Rubidium (Rb), Strontium (Sr), Caesium (Cs), and Barium (Ba).

8. The liquid metal battery of claim 1 wherein the cathodic metal is selected from the group consisting of: Zinc (Zn), Gallium (Ga), Cadmium (Cd), Indium (In), Tin (Sn), Antimony (Sb), Technetium (Te), Mercury (Hg), Thallium (Tl), Lead (Pb), and Bismuth (Bi).

9. The liquid metal battery of claim 1 wherein the anodic metal comprises lithium (Li) and the cathodic metal comprises lead (Pb).

10. The liquid metal battery of claim 1 wherein the anodic metal comprises magnesium (Mg) and the cathodic metal comprises antimony (Sb).

1 1 . The liquid metal battery of claim 1 wherein at least a portion of a top wall of the upper electrically conductive anodic canister comprises a downwardly-extending antennae dimple, wherein a lower end of the antennae dimple is sized and shaped so as to be in electrical contact with the liquefied anodic metal.

12. The liquid metal battery of claim 9 wherein the antennae dimple comprises a downwardly-extending ridge.

13. The liquid metal battery of claim 9 wherein the antennae dimple comprises a downwardly-extending conical shape.

14. The liquid metal battery of claim 1 wherein the battery is cylindrical in shape.

15. The liquid metal battery of claim 1 wherein an open bottom of the upper canister is fitted telescopically into the open top of the lower canister.

16. The liquid metal battery of claim 1 wherein the upper canister and lower canister are in threaded engagement.

17. The liquid metal battery of claim 1 wherein the liquid seal comprises a compression seal.

18. The liquid metal battery of claim 1 wherein the liquid seal comprises flanged tabs.

19. The liquid metal battery of claim 16 wherein the liquid seal further comprises ceramic, non-conductive bolts.

20. The liquid metal battery of claim 16 wherein the liquid seal further comprises a high-temperature gasket.

21 . The liquid metal battery of claim 1 wherein the upper canister is manufactured out of stainless steel.

22. The liquid metal battery of claim 1 wherein at least a portion of the interface between at least one of the upper canister and the anodic metal and the lower canister and the cathodic metal comprises a platinum coating applied to at least one of the upper canister and lower canister.

23. The liquid metal battery of claim 1 further comprising a vacuum head space in the upper canister above the anodic metal.

24. The liquid metal battery of claim 1 further comprising a flared opening at an open end of the lower canister.

25. The liquid metal battery of claim 1 wherein at least one of the upper canister and lower canister comprises crucible-shaped inner walls.

26. The liquid metal battery of claim 1 wherein at least one of the upper canister and lower canister is a vacuum flask comprising a vacuum bottle.

27. The liquid metal battery of claim 1 further comprising a sump around a joint between the upper canister and lower canister.

28. The liquid metal battery of claim 1 further comprising a liquid stabilizer disposed in the electrolyte layer.

29. The liquid metal battery of claim 26 wherein the liquid stabilizer comprises a honeycomb structure.

30. A method of manufacturing a liquid metal battery comprising the steps of:

providing a housing comprising an upper electrically conductive anodic canister, and a lower cathodic canister;

receiving a cathodic metal in the housing; receiving an electrolyte in the housing;

receiving an anodic metal having a density lower than the cathodic metal in the housing; and

sealingly coupling the anodic canister to the cathodic canister and electrically isolating therebewteen.

31 . The method of claim 31 further comprising electrically isolating the upper anodic canister along an interface between the anodic canister and the electrolyte.

32. The method of claim 31 wherein the upper anodic canister has an open bottom and the lower cathodic canister has an open top, further comprising:

inverting the upper anodic canister with open bottom oriented upwards; and wherein

the receiving the anodic metal in the housing comprises introducing liquefied anodic metal through the open bottom;

the receiving the electrolyte in the housing comprises introducing electrolyte through the open bottom on top of the anodic metal;

the receiving the cathodic metal in the housing comprises introducing cathodic metal through the open bottom on top of the electrolyte; and

inverting the lower cathodic canister and sealably coupling the open top with the open bottom of the inverted upper anodic canister.

33. The method of claim 32 wherein before introducing the cathodic metal,

cooling the anodic metal and electrolyte in the anodic canister; and wherein

the receiving the cathodic metal in the housing comprises forming a solid plug of cathodic metal and inserting same through the open bottom on top of the solidified electrolyte, the cathodic metal protruding from the open top.

34. The method of claim 32 further comprising inverting the sealably coupled upper anodic canister and lower cathodic canisters before thermal activation.

35. The method of claim 30 further comprising sealingly coupling the anodic canister to the cathodic canister, wherein an interface between the anodic canister and the cathodic canister is disposed adjacent the electrolyte.

36. The method of claim 30 further comprising the step of heating the anodic and cathodic metals to a specified operating temperature.

37. The method of claim 30 wherein one or more steps are performed in a vacuum, under high temperature conditions.

38. The method of claim 30 wherein one or more steps is performed in an inert gas environment at ambient temperatures.

39. The method of claim 30 further comprising, before assembly, stamping an antennae dimple in a top wall of the upper canister, wherein a lower end of the antennae dimple is sized and shaped to be in electrical contact with the liquefied anodic metal.

40. The method of claim 30 wherein the upper canister comprises a temporary top access port and wherein the steps of receiving a cathodic metal in the housing, receiving an electrolyte in the housing, and receiving an anodic metal in the housing are performed through the temporary top access.

41 . The method of claim 40 further comprising the step of sealing the temporary top access.

42. The method of claim 40 wherein the steps of receiving a cathodic metal in the housing, receiving an electrolyte in the housing, and receiving an anodic metal in the housing are performed in that order.

43. The method of claim 30 wherein the cathodic metal, the electrolyte, and the anodic metal are in liquid form while being received in the housing.

44. The method of claim 36 further comprising the step of cooling the cathodic metal, the electrolyte, and the anodic metal after they are received in the housing.

45. The method of claim 30 wherein:

receiving the cathodic metal in the housing comprises introducing a liquefied cathodic metal thereto;

receiving an electrolyte in the housing comprises introducing a molten electrolyte thereto; and

receiving the anodic metal in the housing comprises introducing a liquefied cathodic metal thereto.

46. The method of claim 30 wherein:

receiving the cathodic metal in the housing comprises introducing liquefied cathodic metal to the lower canister and allowing it to cool;

receiving the electrolyte in the housing comprises introducing molten electrolyte onto the cathodic metal and allowing it to cool; and

receiving an anodic metal in the housing comprises introducing liquefied anodic metal onto the electrolyte and allowing it to cool.

47. The method of claim 30 wherein: receiving the cathodic metal in the housing comprises filling the lower canister with cathodic metal and allowing it to cool;

receiving an anodic metal in the housing comprises filling the upper canister with liquefied anodic metal and allowing it to cool; and

receiving the electrolyte in the housing comprises filling a space between the cathodic metal and anodic metal with the electrolyte.

48. The method of claim 30 further comprising the step of coating a platinum type conductor on at least a portion of the inner wall of the housing.

49. The method of claim 30 further comprising coating an ceramic coating on the upper conductive canister at the interface between the upper conductive canister and the electrolyte layer.

50. The method of claim 30 wherein the steps of receiving a cathodic metal in the housing and receiving an anodic metal in the housing comprises a single step of receiving a metal alloy in the housing, the metal alloy comprising the anodic metal and cathodic metal.