SE539508C2 - A hydrogen generating device - 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

A HYDROGEN GENERATING DEVICEThe 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; and Fig. 6 is a perspective view of a two part fuel card; card; g 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 ofthe 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. 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 ofthe 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 if the 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 of the invention. ln fact the form of the 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 first 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 isjust one possible solution to the problem of providing aconnection and a fluid communication, and the inventive concept goes beyond thisembodiment.

Claims (10)

Hydrogen generating unit (202; 500; 700; 800), characterized by a first part (500a; 701; 802a) having a first space (502a) containing at least one component capable of generating hydrogen when it is brought into contact with a suitable reagent; a second portion (500b, 702, 802b) having a second space (502b) containing at least one reagent solution, which solution is capable of generating hydrogen gas when contacted with the component (s) of the first space in the first portion; that the first and the second part are separate parts which can be connected together and where the first and the second part comprise complementary means (504, 506, 508) which when the parts are connected together to form an assembly provide a single-flow connection between the first and the second space , enabling contact between the component and the reagent solution, an outlet (216) through which hydrogen can be provided, and wherein the first and second portions are flat structures configured to be interconnected end-to-end to form a short unit. Device according to claim 1, modified in that the first and the second part are plate structures which are configured to be connected surface-to-surface to form a short-shaped unit. Device according to claim 1, modified in that the first and the second part are tubular structures which are configured to be connected end-to-end. Device according to any one of the preceding claims, wherein the first component is a metal, preferably aluminum, and wherein the reagent solution has a pH above 12, preferably a solution of a member of the group consisting of KOH, NaOH, LiOH, I \ / | g (OH) 2, Ca (OH) 2. Device according to claim 4, wherein the metal is provided in the form of one of a net, a honeycomb structure, a powder, grains, strips, solid metal pieces, strips or rods. The device of claim 3, wherein the reagent solution comprises water, an alkali metal hydroxide, preferably NaOH and a catalytic salt such as NaCl, KCl, IVIgCl 2. Device according to any one of the preceding claims, wherein the complementary means comprise a barrier element which seals the space containing the reagents in the second part; a barrier breaking element arranged to break the barrier in the second part when the first and the second part are connected to each other. The device of claim 7, wherein the barrier breaking element is configured to break the barrier when the first and second members are brought together. The device of claim 8, wherein the barrier breaking element is configured to break the barrier in a subsequent step after the first and second parts are brought together. Device according to one of the preceding claims, which has a geometric element which deviates from flatness.