SE1451238A1 - Hydrogen generating device and method and fuel cell device utilising such - Google Patents

Abstract

ABSTRACT The invention relates to a hydrogen generator (202; 500; 700; 800) comprising two parts(500a, 500b), either separate orjoined by a hinge. Each part comprises a compartment(502a, 502b) housing components of a reaction mixture that when brought in contact witheach other generates hydrogen. The two parts are complementary in that they have onepart each of a means (504, 506, 508) for establishing of a fluid communication between theparts. This means can constitute a barrier (506) and a barrier breaking means (508). (Fig. 5b)

Description

HYDROGEN GENERATING DEVICE AND METHOD AND FUEL CELL DEVICE UTILISING SUCHThe present invention relates to the generation of hydrogen gas as a fuel for e.g. fuel cells.Background of the lnvention Over the last decade fuel cell technology has developed considerably and now there aredevices available that are powered by fuel cells to deliver electricity for charging devicessuch as cell phones, lap-tops, surf pads etc.

Such devices are powered by fuels such as butane, methanol or hydrogen. Hydrogen caneither be supplied stored in small cartridges or can be produced on demand in the deviceitself. Commonly the latter is based on bringing a reagent in contact with water whereby achemical reaction starts to produce hydrogen gas.

Examples of a product employing such a system is the POWER TREKKTM charger (by myFC AB,Sweden).

The technology for this type of hydrogen generation is patented in i.a. US-8,632,928 (Signa),which discloses a water reactive hydrogen fueled power system including devices tocombine reactant fuel materials and aqueous solutions to generate hydrogen. The generatedhydrogen is converted in a fuel cell to provide electricity. The water reactive hydrogen fueledpower system includes a fuel cell, a water feed tray, and a fuel cartridge to generate powerfor portable power electronics. The removable fuel cartridge is encompassed by the waterfeed tray and fuel cell. The water feed tray is refillable with water by a user. The water isthen transferred from the water feed tray into the fuel cartridge to generate hydrogen forthe fuel cell which then produces power for the user. ln US 2013/251626 (Signa) systems, devices and methods are described which combinethermally stable reactant materials and aqueous solutions to generate hydrogen and a non-toxic liquid by-product. The reactant materials can be sodium silicide or sodium silica gel.The hydrogen generation devices are used in fuels cells and other industrial applications.One system combines cooling, pumping, water storage, and other devices to sense andcontrol reactions between reactant materials and aqueous solutions to generate hydrogen.Springs and other pressurization mechanisms pressurize and deliver an aqueous solution tothe reaction. A check valve and other pressure regulation mechanisms regulate the pressureof the aqueous solution delivered to the reactant fuel material in the reactor based uponcharacteristics of the pressurization mechanisms and can regulate the pressure of thedelivered aqueous solution as a steady decay associated with the pressurization force. Thepressure regulation mechanism can also prevent hydrogen gas from deflecting the pressureregulation mechanism.

These prior art systems are inherently bulky, and it would be desirable to reduce thedimensions of the hydrogen generating part of charger devices so as to reduce the overallsize of the charger system. Also the power density is insufficient for certain purposes.

Summary of the lnvention ln order to overcome i.a. the bulkiness problem, the present inventors have devised a novelapparatus, which is based on another type of Chemistry, and which provides a much lessbulky unit. Also the achievable power density is higher than in comparable systems in theprior art.

The novel apparatus is defined in claim 1.

Preferred embodiments are defined in the dependent claims.

Brief Description of the Drawings The invention will be described below in detail with reference to the drawing figures, inwhich Fig. 1 shows a prior art apparatus, using the Signa technology for hydrogen generation;Fig. 2 schematically illustrates the novel system; Fig. 3 shows an example of a shape of a fuel generator unit; Fig. 4 schematically illustrates a sealing and valve function; Fig. 5 schematically illustrates the design of a fuel card; Fig. 6 is a perspective view of a two part fuel card; Fig. 7 is a further embodiment of a two part fuel card; and Fig. 8 illustrates another embodiment of a two part fuel card wherein the parts are hinged soas to be foldable.

Detailed Description of the lnvention Fig. 1 shows a system 100 according to prior art as disclosed in US-8,632,928 (Signa)mentioned in the background. lt comprises a fuel cell 110, fuel cartridge 120 and water feed tray 130 in which water 199can be added. The cartridge contains a reactant fuel material 177, which can include e.g.sodium silicide, and activators, catalysts and/or additives of various kinds. The cartridge issupplied as a separate item to be inserted in a dedicated compartment in a charger device.Water is added and a reaction is initiated such that hydrogen 188 is evolved, and passed tothe fuel cell which generates electricity.

As can be seen in the figure the system comprises a number of mechanical components suchas springs, valves 140, a poppet 150. Thus, this constitutes a relatively complex mechanicaldesign, and the invention aims at providing a simpler and less bulky system.

One basic idea of the inventive concept behind the present invention is to make the fuelcartridge very thin, in one embodiment the size of the cartridge could be comparable to thesize and thickness of a credit card or slightly thicker. This embodiment will herein be referredto as a ”fuel card”. This is illustrated in Fig. 2 which schematically shows a fuel cell drivencharger device 200 and a fuel card 202. The fuel card 202 is insertable in a slot 204 of thecharger device 200.

The fuel card must be activated to start the reaction that produces hydrogen (this will bedescribed further below). Once the hydrogen evolving reaction has been initiated the gasmust of course be passed on to the fuel cell. This is achieved by providing a valve function inthe card that opens when a mating element inside the slot cooperates with the valve on thefuel card when the fuel card has been inserted in the charger device through the slot.

Another fundamental feature of the invention is that the fuel card should be provided to theuser as two separated parts, one containing at least the water, possibly also some of theother reactants, and the other part contains the rest of the chemistry that, when combinedwith the water and any other component(s) in the first fuel card part, reacts to generate thehydrogen.

Having said that, it should be noted that the fuel cartridge does not necessarily have to beflat and thin. However, this is the preferred design. lt could have other shapes such ascylindrical or tube shaped. ln this embodiment the two are joined end-to-end having thesame functional members to provide fluid communication and hydrogen generation as inthe other embodiments described herein. ln a particularly preferred variant the fuel card is a generally flat structure, but having somegeometric feature that deviates from flatness. One not limiting example is shown in Fig. 3a.Here the cross section of the cartridge has the shape of a keyhole. Further possible examplesof shapes are shown as front views of the fuel card in Figs 3b-f. ln these embodiments theslot 204 in the charger device 200 must have a mating shape. This design is beneficial in thatit i.a. avoids misplacing the cartridge in the charger.

Of course the deviating shape element need not extend along the entire flat structure butcould equally well be provided at one or both edges only, the former embodiment beingexemplified in Fig. 3g in a side view in perspective.

The hydrogen that is generated in the fuel card upon activation must be transferred to thefuel cell in a safe and efficient way. The principle is disclosed in Fig. 4a-b, which shows a fuelcard 202 inserted through the slot 204 of a charger device 200.

The encircled portion is magnified in Fig. 4b and shows a cross-section of the assembly asimple mechanism for enabling a sealed connection between the fuel card 202 and thecharger 200. Namely, inside the charger, near or at the ”bottom” of the compartment 201 into which the fuel card 202 is inserted through the slot 204 there is provided one or moreelevated parts 206, which have a sloping/inclined leading surface 208 of said elevated part206, and optionally (as shown) an essentially horizontal surface 210. Thus, when the fuelcard is inserted and reaches the bottom of the compartment it encounters the slopingsurface 208 whereby the fuel card is force upwards towards the roof 212 of saidcompartment. ln the compartment there is a valve unit 214 that mates with a gas outlet 216in the fuel card 202. When the two members, i.e. the valve 214 and the gas outlet 216 arebrought into contact the gas starts to flow from the fuel card and into the fuel cells in thecharger. Due to the squeezing action of the elevated part 206 there will be a tight sealbetween the parts. Preferably there should be provided sealing elements, such as softmaterials that easily deform so as to provide the seal. Standard components such as O-ringscould be used for this purpose. Silicon materials or the like, integrated in the fuel card isanother option.

Preferably the fuel card is supplied to the user in two parts that are combined just prior touse. The reason for this being appropriate is that hydrogen mixed with air constitutes anexplosive and ifthe chemicals in a fuel card inadvertently should start to react a hazardoussituation could occur.

Thus, in one embodiment a first component part of a fuel card contains a compartment inwhich there is provided a first chemical or a selection of chemicals that when brought incontact with water at a suitable pH will begin to generate hydrogen. Preferably the pH > 12. ln particular the present invention makes use of aluminium and aqueous hydroxide, e.g.NaOH according to the reaction zA| + soH' (aq) à sHz + zA|(oH)3 Suitably a catalyst is included in the reaction, and any of NaCl, KCI, IVIgCIZ, CaClz or a mixturethereof is at present a preferred catalyst. Without wishing to be bound by theory it isbelieved that the catalyst in the form of said compounds contributes to heating the systemby virtue of its heat of dissolution, and also speeds up the overall reaction shown above.

Other possible hydroxides are KOH, LiOH, I\/|g(OH)2, Ca(OH)2, to mention a few.

One embodiment of a fuel card 500 comprising two complementary parts, a first part 500aand a second part 500b, is schematically shown in Figs. 5a-b. These complementary parts arecomplementary in the sense that they are provided with one each of a complementary parof means that when joined provides a fluid communication between the two parts.

Thus, Fig. 5a shows a fuel card in an assembled state, i.e. where the two component partshave been joined end-to-end, and Fig. 5b shows a state just before they are joined. ln a preferred embodiment, the first part 500a has a compartment 502a in which there isprovided aluminium and a catalyst (not shown). The aluminium is preferably provided in aform selected from foil strips, powder, solid metal pieces, mesh structures, honey-combstructures, ribbons, rods or combinations thereof, although the specific form is not important for the purpose ofthe invention. ln fact the form ofthe aluminium is chosen so asto optimize the required rate of hydrogen generation. Here the active surface of thealuminium is of importance, where powder inherently has a very much larger active surfacethan solid metal.

The second part 500b contains a compartment 502b in which there preferably is provided anaqueous solution of a hydroxide such as NaOH or KOH (not shown).

Alternatively there could be provided separate compartments for water and the solidhydroxide, and provisions are made for mixing them prior to use.

As can be seen in Fig. 5b, the first part has an aperture 504 which is covered by a barrier 506that can be penetrated so as to provide access to the interior of the compartment whereinthe aluminium is located. The barrier should thus be made of thin but comparatively durablematerial. Suitably the barrier is an aluminium foil, but any material that can withstandnormal handling and provide adequate sealing would do. Polymer materials are examples ofsuch materials.

The second part 500b is provided with a dispensing nozzle 508 which in one embodiment isan essentially cylindrical element having a channel 510 running there through which is influid communication with the compartment 502b in the second part 500b.

The nozzle is provided with a circumferential flange 509 that has a slightly wider diameterthan the cylindrical nozzle and is shaped like a truncated cone. The flange diameter is alsoslightly larger than the aperture 504 in the fist part 500a. Furthermore, the nozzle is suitablymade of a resilient material such that a slight force exerted upon inserting the nozzle will berequired to deform the flange slightly. During insertion the barrier 506 will break and a fluidcommunication between compartments 502 and 502b is established. Once inside the twoparts 500a and 500b will be locked to each other since the nozzle 508 no longer can bewithdrawn due to the flange being hooked to corresponding stopping elements 512 insidethe compartment 502a in part 500a. ln Fig. 6 the two part fuel card 202 comprising the first part 502a and the second part 502bwith the nozzle 508 is schematically shown in a perspective view before having beenassembled end-to-end. lt should be emphasized that this is just one possible solution to the problem of providing aconnection and a fluid communication, and the inventive concept goes beyond thisembodiment.

Another completely different way of achieving the same result is schematically illustrated inFig 7.

Here the device 700 comprises two equally sized flat members, a first 701 and a second 702flat member, respectively, that when brought together face-to-face, i.e. on top of each otherlike a sandwich, to form the final fuel card.

The first flat members 701, contains the aluminium and optionally a catalyst in suitable formas discussed above. lf in powder form it needs to be held in place by a liquid permeablemembrane, such as a fine mesh, a wicking material or the like.

The second flat member 702 contains the liquid and remaining components. Here a non-liquid permeable barrier 704 is provided.

The first member is provided with rails 706 mating with guiding recesses 708 in the secondflat member. The first member 701 is also provided with cutting elements 710 suitablyprovide as elongated edges.

Thus, in order to set the fuel card up for operation, the two flat members are broughttogether in a slightly off set position, indicated in Fig. 7b. The rails are fitted in the recessesand the first flat member 701 (upper in Fig. 7b) is slid along the second part (lower in Fig,7b), whereby the cutting elements 710 cut through the barrier 704 so as to bring thechemicals in contact and the hydrogen generating reaction is initiated.

A still further possible embodiment is shown in Fig. 8.

Here the two parts containing the same components as in the other embodiments, i.e. arespective one containing at least the water, possibly also some ofthe other reactants, andthe other part contains the rest of the chemistry that, when combined with the water andany other component(s) in the first fuel card part, reacts to generate the hydrogen.

Thus, in Fig. 8a is shown schematically a foldable ”fuel card” 800 which comprises a first part802a and a second part 802b joined at one end by a hinge 804. The hinge can be of anyconstitution, but preferably it is simply a thinner portion ofthe material from which the fuelcard is made, i.e. some suitable polymer. However, it should be flexible enough to becapable of being bent about 360° without breaking, and thus if the card material is selectedto be relatively rigid for robustness, the hinge 804 could be made from a softer material.

Fig. 8b shows the two parts folded together such that the two opposing ends meet. At thefree ends there are provide complementary means, such as described in connection with Fig.

Thus, as very schematically indicated in Fig. 8b by broken vertical lines, a fluidcommunication path 806 is established when the foldable fuel card 800 is folded togethersuch the ends meet.

The fluid communication is provided similarly to the embodiment in Fig. 5.lt should be noted that it is not strictly necessary that the two parts be equally sized. ln that case of course the fluid communication will be established at some other point on the longerof the two parts, as schematically shown in Fig. 8c.

Claims (13)

1. CLAll\/IS:1. A hydrogen generator device (202; 500; 700; 800), comprising a first part (500a; 701; 802a) having a first compartment (502a) containing atleast one component capable of generating hydrogen when brought in contact with asuitable reagent; a second part (500b, 702, 802b) having a second compartment (502b)containing at least a reagent solution, the solution being capable of generating hydrogen gaswhen brought in contact with said at least one component in the first compartment of thefirst part; said first and second parts comprising complementary means (504, 506, 508)which when the parts are connected to form an assembly provide a fluid communicationpath between said first and second compartments, enabling contact between thecomponent and the reagent solution; and an outlet (216) through which hydrogen gas can be supplied.
2. 2. The device according to claim 1, wherein the first and second parts are separate partswhich are connectable.
3. 3. The device according to claim 1, wherein the first and second parts are joined at one endby a hinge structure (804), and foldable to connect the free ends of the respective parts, saidfree ends being provided with said complementary means.
4. 4. The device according to claim 1, wherein the first and the second parts are flat structureswhich are configured to be connected face-to-face to form a card shaped unit.
5. 5. The device according to claim 1, wherein the first and the second parts are flat structuresthat are configured to be connected end-to-end to form a card shaped unit.
6. 6. The device according to claim 1, wherein the first and the second parts are tube shapedstructures which are configured to be connected end-to-end.
7. 7. The device according to any preceding claim, wherein the first component is a metal,preferably aluminium, and wherein the reagent solution has a pH above 12, preferably asolution of a member ofthe group consisting of KOH, NaOH, LiOH, I\/|g(OH)2,Ca(OH)2.
8. 8. The device according to claim 7, wherein the metal is provided as one of a mesh, a honey-comb structure, a powder, grains, strips, solid metal pieces, ribbons or rods.
9. 9. The device according to claim 5 or 6, wherein the reagent solution comprises water, analkali metal hydroxide, preferably NaOH, and a catalytic salt, such as NaCl, KCI, IVIgCIZ.
10. 10. The device according to any preceding claim, wherein the complementary meanscomprise a barrier element sealing the compartment housing the reagents in said secondpart; a barrier rupturing element arranged to break the barrier in said second partwhen the first and second parts are connected to each other.
11. 11. The device according to claim 10, wherein the barrier rupturing element is configured tobreak the barrier when the first and second parts are brought together.
12. 12. The device according to claim 10, wherein the barrier rupturing element is configured tobreak the barrier in a subsequent step after the first and second parts have been broughttogether.
13. 13. The device according to any preceding claim, having a shaped form element provided ona surface thereof.