Patent Description:
Hearing aids have become more and more advanced over the years. This is partly a result of new hardware and development of new algorithms. This has greatly improved the experience of the users. One of the traditional bottlenecks of hearing aid design is the power consumption. Most modern hearing aids use single use batteries such Zn air batteries.

Fuel cells such as direct Methanol fuel cells have been suggested as an alternative power source for hearing aids. One advantage of using fuel cells is that refuelling operations may be conducted fast e.g. in less than a minute.

<CIT> discloses an apparatus for fuelling a fuel-cell-powered device having a profile and a fuel inlet. The apparatus comprises at least one fuel port having an outlet and at least one adaptor associated with the fuel port. The adaptor is configured to receive the fuel-cell-powered device. Means for releasably and sealingly engaging the fuel inlet of the fuel-cell-powered device to the outlet of the fuel port are also provided.

<CIT> discloses a fuel cell system including an auxiliary device disposed between a fuel cartridge and a power generating device. The auxiliary device includes a pump, a valve and a pressure regulation mechanism. The fuel cartridge is constructed in a double structure which is provided with a main body container and a bag shaped container disposed in the inside of the main body container. A portion between the inner side of the main body container and the outer side of the bag shaped container is formed to be a collection tank for collecting a product generated in the power generating device. The main body container is provided with an inflow port, an outflow port, and an exhaust port.

<CIT> discloses a fuel mixer supplying fuel to an anode of a direct liquid feed fuel cell stack from a liquid fuel cartridge. Air is supplied to a cathode of the direct liquid feed fuel cell stack.

It remains however a problem to provide a refuelling unit capable of handling the small amount of fuel needed for a small fuel cell such as a fuel cell powering a hearing aid.

According to a first aspect, the invention relates to a refueling unit for refueling a fuel cell, said refueling unit comprising.

wherein said refuelling unit is configured to receive through said waste inlet a waste fluid stored in a fuel reservoir of a fuel cell connected to said fuel cell receiving section, wherein said refuelling unit further comprises an intermediate fuel reservoir for storing fuel, said intermediate fuel reservoir being fluidly connected to said fuel inlet of said cartridge receiving section and said fuel outlet of said fuel cell receiving section, wherein said refuelling unit is configured to firstly receive in said intermediate fuel reservoir a predetermined amount of fuel from a cartridge connected to said cartridge receiving section and secondly empty said intermediate fuel reservoir and guide said fuel stored therein out of said fuel outlet of said fuel cell receiving section and into the fuel reservoir of a fuel cell connected to said fuel cell receiving section.

Consequently, a simple refuelling unit capable of providing a precise amount of new fuel into the fuel reservoir is provided.

The fuel may be methanol i.e. the fuel cell may be a direct methanol fuel cell. The waste fluid may be residual methanol stored in the fuel reservoir of the fuel cell. The intermediate fuel reservoir may contain between <NUM> and <NUM>, between <NUM> and <NUM>, or between <NUM> and <NUM>. The fuel outlet and the fuel inlet of the fuel cell receiving section may be two different fluid connection ports or they may be combined into a single inlet / outlet fluid connection port. The cartridge may contain an amount of fuel for at least <NUM> refuelling operations, at least <NUM> refuelling operations or at least <NUM> refuelling operations. The refuelling unit may comprise one or more pumps configured to pump fuel into the intermediate fuel reservoir and out of the fuel outlet of the fuel cell receiving section.

In some embodiments said refueling unit further comprises a first piston and an actuator, wherein said first piston is configured to be movable in said intermediate fuel reservoir between a first position and a second position, said refuelling unit being configured to receive in said intermediate fuel reservoir a predetermined amount of fuel from a cartridge connected to said cartridge receiving section by moving said first piston from said first position to said second position using said actuator, and secondly empty said intermediate fuel reservoir and guide said fuel stored therein out of said fuel outlet of said fuel cell receiving section by moving said first piston from said second position to said first position using said actuator.

Consequently, the intermediate fuel reservoir may in a simple manner be provided with a predetermined amount of fuel.

The refuelling unit may comprise a control unit configured to control the actuator. The control unit may detect (manually or automatically) when a fuel cell is received at the fuel cell receiving section and send control signals to the actuator.

In some embodiments said intermediate fuel reservoir is fluidly connected to said fuel inlet of said cartridge receiving section via a one-way valve allowing fluid flow only from said fuel inlet of said cartridge receiving section to said intermediate fuel reservoir.

In some embodiments said intermediate fuel reservoir is fluidly connected to said fuel outlet of said fuel cell receiving section via a one-way valve allowing fluid flow only from said intermediate fuel reservoir to said fuel outlet of said fuel cell receiving section.

In some embodiments said refueling unit further comprises an intermediate waste reservoir and a waste outlet, said intermediate waste reservoir being fluidly connected to said waste inlet of said fuel cell receiving section and said waste outlet, said refueling unit being configured to receive a waste fluid through said waste inlet from a fuel reservoir of a fuel cell connected to said fuel cell receiving section by firstly receiving in said intermediate waste reservoir said waste fluid and secondly empty said intermediate waste reservoir and guide said waste fluid stored therein out of said waste outlet.

In some embodiments said refueling unit further comprises a second piston, wherein said second piston is configured to be movable in said intermediate waste reservoir between a first position and a second position, said refuelling unit being configured to receive in said intermediate waste reservoir a waste fluid from a fuel reservoir of a fuel cell connected to said fuel cell receiving section by moving said second piston from said first position to said second position, and secondly empty said intermediate waste reservoir and guide said waste fluid stored therein out of said waste outlet by moving said second piston from said second position to said first position.

The amount of waste fluid stored in the fuel reservoir of the fuel cell may vary. Thus, the fuel reservoir of the fuel cell or the refuelling unit may be provided with an under pressure valve configured to open and allow an auxiliary fluid e.g. atmospheric air, to enter the intermediate waste reservoir if the vacuum in the intermediate waste reservoir exceeds a particular value.

In some embodiments said intermediate waste reservoir is fluidly connected to said waste inlet of said fuel cell receiving section via a one-way valve allowing fluid flow only from said waste inlet to said intermediate waste reservoir.

In some embodiments said intermediate waste reservoir is fluidly connected to said waste outlet via a one-way valve allowing only fluid flow from said intermediate waste reservoir to said waste outlet.

In some embodiments said actuator is configured to move said second piston from said first position to said second position, and from said second position to said first position.

In some embodiments said first piston is mechanically coupled to said second piston via a force transferring element so that said first piston and said second piston simultaneously move from the first position to the second position and from the second position to the first position, whereby the intermediate fuel reservoir is filed with fuel at the same as the intermediate waste reservoir receives waste fluid, and the fuel stored in the intermediate fuel reservoir is guided out of said intermediate fuel reservoir at the same time as the waste fluid is guided out of said intermediate waste reservoir.

Consequently, a fast and simple refueling unit is provided.

In some embodiments said fuel outlet and said waste inlet of said fuel cell receiving section are combined into a single inlet / outlet fluid connection port for being fluidly connected to a combined inlet / outlet fluid connection port of a fuel reservoir of a fuel cell.

Consequently, by having a combined single inlet / outlet fluid connection port less space is required on the fuel reservoir of the fuel cell for providing the connection to the refueling unit.

According to a second aspect the invention relates to a system comprising a refuelling unit as disclosed in relation to the first aspect of the invention and a hearing aid fitted with a fuel cell having a fuel reservoir with a single combined inlet / outlet fluid connection port connectable to the fuel cell receiving section of the refueling unit.

In some embodiment the system further comprises a cartridge connectable to the cartridge receiving section of the refueling unit.

According to a third aspect the invention relates to a method of refueling a fuel cell using a refueling unit as disclosed in relation to the first aspect of the invention, comprising the steps of:.

The different aspects of the present invention can be implemented in different ways including as refuelling units and systems comprising such refuelling units described above and in the following, each yielding one or more of the benefits and advantages described in connection with at least one of the aspects described above, and each having one or more preferred embodiments corresponding to the preferred embodiments described in connection with at least one of the aspects described above and/or disclosed in the dependant claims. Furthermore, it will be appreciated that embodiments described in connection with one of the aspects described herein may equally be applied to the other aspects.

The above and/or additional objects, features and advantages of the present invention, will be further elucidated by the following illustrative and non-limiting detailed description of embodiments of the present invention, with reference to the appended drawings, wherein:.

In the following description, reference is made to the accompanying figures, which show by way of illustration how the invention may be practiced.

<FIG> shows a schematic drawing of a refuelling unit <NUM> for refuelling a fuel cell according to an embodiment of the present invention. The refueling unit <NUM> comprises a fuel cell receiving section <NUM>, a cartridge receiving section <NUM> and an intermediate fuel reservoir <NUM>. The fuel cell receiving section <NUM> has a fuel outlet <NUM> for being fluidly connected to a fuel inlet of a fuel reservoir of a fuel cell and waste inlet <NUM> for being fluidly connected to a waste outlet of the fuel reservoir of the fuel cell. The cartridge receiving section <NUM> has a fuel inlet <NUM> for being fluidly connected with a fuel outlet of a cartridge comprising a fuel for refuelling the fuel cell. The refuelling unit <NUM> is configured to receive through the waste inlet <NUM> a waste fluid stored in a fuel reservoir of a fuel cell connected to the fuel cell receiving section <NUM>. The waste fluid may be guided <NUM> out of the refuelling unit <NUM> or guided <NUM> into the cartridge receiving section <NUM> for providing the waste fluid to a cartridge. The intermediate fuel reservoir <NUM> is fluidly connected to the fuel inlet <NUM> of said cartridge receiving section <NUM> and the fuel outlet <NUM> of said fuel cell receiving section <NUM>. The refuelling unit is configured to firstly receive in the intermediate fuel reservoir <NUM> a predetermined amount of fuel from a cartridge connected to the cartridge receiving section <NUM> and secondly empty the intermediate fuel reservoir <NUM> and guide the fuel stored therein out of the fuel outlet <NUM> of the fuel cell receiving section <NUM> and into the fuel reservoir of a fuel cell connected to the fuel cell receiving section <NUM>. The fuel outlet <NUM> and the waste inlet <NUM> of the fuel cell receiving section <NUM> may be combined into a single inlet / outlet fluid connection port <NUM> for being fluidly connected to a combined inlet / outlet fluid connection port of a fuel reservoir of a fuel cell.

<FIG> shows a schematic drawing of a refuelling unit <NUM> for refuelling a fuel cell according to an embodiment of the present invention. The refueling unit <NUM> comprises a fuel cell receiving section <NUM>, a cartridge receiving section <NUM>, an intermediate fuel reservoir <NUM>, an intermediate waste reservoir <NUM> and a waste outlet <NUM>. The fuel cell receiving section <NUM> has an inlet / outlet fluid connection port <NUM>. A fuel cell <NUM> e.g. of a hearing aid, is connected to the fuel cell receiving section <NUM>. The inlet / outlet fluid connection port <NUM> is connected to an inlet / outlet port <NUM> of a fuel reservoir <NUM> of the fuel cell <NUM>. A cartridge <NUM> comprising a fuel for refuelling the fuel cell <NUM> is connected to the cartridge receiving section <NUM>. The cartridge receiving section <NUM> has a fuel inlet <NUM> connected to a fuel outlet <NUM> of the cartridge <NUM>.

The intermediate fuel reservoir <NUM> is fluidly connected to the fuel inlet <NUM> of the cartridge receiving section <NUM> via a one-way valve <NUM> allowing fluid flow only from the fuel inlet <NUM> of said cartridge receiving section <NUM> to the intermediate fuel reservoir <NUM>. The intermediate fuel reservoir <NUM> is fluidly connected to the inlet / outlet fluid connection port <NUM> via a one-way valve <NUM> allowing fluid flow only from the intermediate fuel reservoir <NUM> to the inlet / outlet fluid connection port <NUM> of the fuel cell receiving section <NUM>.

The intermediate waste reservoir <NUM> is fluidly connected to inlet / outlet fluid connection port <NUM> via a one-way valve <NUM> allowing fluid flow only from the inlet / outlet fluid connection port <NUM> of the fuel cell receiving section <NUM> to the intermediate waste reservoir <NUM>. The intermediate waste reservoir <NUM> is fluidly connected to waste outlet <NUM> via a one-way valve <NUM> allowing fluid flow only from the intermediate waste reservoir <NUM> to the waste outlet <NUM>.

The refueling unit comprises further a first piston <NUM>, a second piston <NUM> and an actuator <NUM>. The first piston <NUM> is configured to be movable in the intermediate fuel reservoir <NUM> between a first position (illustrated by the dotted line <NUM>) and a second position (illustrated by the dotted line <NUM>). The second piston <NUM> is configured to be movable in the intermediate waste reservoir <NUM> between a first position (illustrated by the dotted line <NUM>) and a second position (illustrated by the dotted line <NUM>). The refuelling unit <NUM> is configured to receive in the intermediate fuel reservoir <NUM> a predetermined amount of fuel from the cartridge <NUM> connected to the cartridge receiving section <NUM> by moving the first piston <NUM> from the first position <NUM> to the second position <NUM> using the actuator <NUM>, and secondly empty the intermediate fuel reservoir <NUM> and guide the fuel stored therein out of the inlet / outlet fluid connection port <NUM> of the fuel cell receiving section <NUM> by moving the first piston <NUM> from the second position <NUM> to the first position <NUM> using the actuator <NUM>. The refuelling unit <NUM> is configured to receive in the intermediate waste reservoir <NUM> a waste fluid from the fuel reservoir <NUM> of the fuel cell <NUM> connected to the fuel cell receiving section <NUM> by moving the second piston <NUM> from the first position <NUM> to the second position <NUM>, and secondly empty the intermediate waste reservoir <NUM> and guide the waste fluid stored therein out of the waste outlet <NUM> by moving the second piston <NUM> from the second position <NUM> to the first position <NUM>.

The first piston <NUM> may be mechanically coupled to the second piston <NUM> via a force transferring element so that the first piston <NUM> and the second piston <NUM> simultaneously move from the first position <NUM><NUM> to the second position <NUM><NUM> and from the second position <NUM><NUM> to the first position <NUM><NUM>, whereby the intermediate fuel reservoir <NUM> is filled with fuel at the same as the intermediate waste reservoir <NUM> receives waste fluid, and the fuel stored in the intermediate fuel reservoir <NUM> is guided out of said intermediate fuel reservoir <NUM> at the same time as the waste fluid is guided out of the intermediate waste reservoir <NUM>.

In one embodiment the one-way valves <NUM>-<NUM> are implemented using a fluid system <NUM> as described further in relation to <FIG>. However, in other embodiments other type of one-way valves may be used.

<FIG> show a fluid system <NUM> according to an embodiment of the present invention. The fluid system <NUM> comprises a first member <NUM>, a membrane sheet <NUM>, and a second member <NUM>. <FIG> shows a top view of the fluid system <NUM>, <FIG> shows a side view of the fluid system <NUM>, <FIG> shows a top view of the first member <NUM>, <FIG> shows a bottom view of the second member <NUM>, and <FIG> shows a top view of the membrane sheet <NUM>. The first member <NUM> has a first surface110, a first inlet / outlet fluid connection port <NUM>, a second inlet / outlet fluid connection port <NUM>, a first flow channel <NUM>, a third flow channel <NUM>, a fifth flow channel <NUM> and a seventh flow channel <NUM>. The membrane sheet <NUM> has a first side <NUM>, a second side <NUM> opposite to said first side <NUM>, a first slit <NUM>, a second slit <NUM>, a third slit <NUM>, and a fourth slit <NUM>. The second member <NUM> has a first surface <NUM>, a third inlet / outlet fluid connection port <NUM>, a second fluid outlet <NUM>, a third fluid inlet <NUM>, a second flow channel <NUM>, a fourth flow channel <NUM>, a sixth flow channel <NUM>, and an eighth flow channel <NUM>. The first side <NUM> of the membrane sheet <NUM> is abutting the first surface <NUM> of the first member <NUM> and the second side <NUM> of the membrane sheet <NUM> is abutting the first surface <NUM> of the second member <NUM>. The first flow channel <NUM> forms a fluid passage from the first inlet / outlet fluid connection port <NUM> towards the first slit <NUM>, the second flow channel <NUM> forms a fluid passage from the first slit <NUM> to the third inlet / outlet fluid connection port <NUM>, the third flow channel <NUM> forms a fluid passage from the second inlet / outlet fluid connection port <NUM> towards the second slit <NUM>, the fourth flow channel <NUM> forms a fluid passage from the second slit <NUM> to the second fluid outlet <NUM>, the fifth flow channel <NUM> forms a fluid passage from the third slit <NUM> to the first inlet / outlet fluid connection port <NUM>, the sixth flow channel <NUM> forms a fluid passage from the third fluid inlet <NUM> towards the third slit <NUM>, the seventh flow channel <NUM> forms a fluid passage from the fourth slit <NUM> to the second inlet / outlet fluid connection port <NUM>, and the eighth flow channel <NUM> forms a fluid passage from the third inlet / outlet fluid connection port <NUM> towards the fourth slit <NUM>. The second member <NUM> has a first cavity portion <NUM> forming part of the second flow channel <NUM>, and a second cavity portion <NUM> forming part of the fourth flow channel <NUM>. The first member <NUM> has a third cavity portion <NUM> forming part of the fifth flow channel <NUM>, and a fourth cavity portion <NUM> forming part of the seventh flow channel <NUM>. The cavity portions <NUM><NUM><NUM><NUM> are configured to allow said membrane sheet to deform into them whereby the slits <NUM>-<NUM> may be opened.

The fluid system <NUM> is configured to allow the membrane sheet <NUM> to deform into the first cavity portion <NUM> and thereby open the first slit <NUM> and enable a fluid to flow from the first inlet / outlet fluid connection port <NUM> to the third inlet / outlet fluid connection port <NUM> via the first slit <NUM> when the pressure at the first slit <NUM> is higher on the first side <NUM> of the membrane sheet <NUM> than on the second side <NUM> of the membrane sheet <NUM>; and wherein the fluid system <NUM> is further configured to secure that the first slit <NUM> is substantially closed when the pressure at the first slit <NUM> is higher on the second side <NUM> of the membrane sheet <NUM> than on the first side <NUM> of the membrane sheet <NUM>.

The fluid system <NUM> is further configured to allow the membrane sheet <NUM> to deform into the second cavity portion <NUM> and thereby open the second slit <NUM> and enable a fluid to flow from the second inlet / outlet fluid connection port <NUM> to the second fluid outlet <NUM> via the second slit <NUM> when the pressure at the second slit <NUM> is higher on the first side <NUM> of the membrane sheet <NUM> than on the second side <NUM> of the membrane sheet <NUM>; and wherein the fluid system <NUM> is further configured to secure that the second slit <NUM> is substantially closed when the pressure at the second slit <NUM> is higher on the second side of the membrane sheet <NUM> than on the first side of the membrane sheet <NUM>.

The fluid system <NUM> is further configured to allow the membrane sheet <NUM> to deform into the third cavity portion <NUM> and thereby open the third slit <NUM> and enable a fluid to flow from the third fluid inlet <NUM> to the first inlet / outlet fluid connection port <NUM> via the third slit <NUM> when the pressure at the third slit <NUM> is higher on the second side <NUM> of the membrane sheet <NUM> than on the first side <NUM> of the membrane sheet <NUM>; and wherein the fluid system <NUM> is further configured to secure that the third slit <NUM> is substantially closed when the pressure at the third slit <NUM> is higher on the first side <NUM> of the membrane sheet <NUM> than on the second side <NUM> of the membrane sheet <NUM>.

The fluid system <NUM> is further configured to allow the membrane sheet <NUM> to deform into the fourth cavity portion <NUM> and thereby open the fourth slit <NUM> and enable a fluid to flow from the third inlet / outlet fluid connection port <NUM> to second inlet / outlet fluid connection port <NUM> via the fourth slit <NUM> when the pressure at the fourth slit <NUM> is higher on the second side <NUM> of the membrane sheet <NUM> than on the first side <NUM> of the membrane sheet <NUM>; and wherein the fluid system <NUM> is further configured to secure that the fourth slit <NUM> is substantially closed when the pressure at the fourth slit <NUM> is higher on the first side <NUM> of the membrane sheet <NUM> than on the second side <NUM> of the membrane sheet <NUM>.

In the illustrated embodiments, the first member <NUM> and the second member <NUM> have different size, i.e. the first member <NUM> is larger than the second member <NUM>. However, in other embodiments, the second member <NUM> may be equal to or larger than the first member <NUM>.

Claim 1:
A refueling unit for refueling a fuel cell, said refueling unit (<NUM>) comprising
• a fuel cell receiving section (<NUM>) having a fuel outlet (<NUM>) adapted for being fluidly connected to a fuel inlet of a fuel reservoir (<NUM>) of a fuel cell (<NUM>), and waste inlet (<NUM>) adapted for being fluidly connected to a waste outlet (<NUM>) of said fuel reservoir (<NUM>) of said fuel cell (<NUM>);
• a cartridge receiving section (<NUM>) having a fuel inlet (<NUM>) adapted for being fluidly connected with a fuel outlet (<NUM>) of a cartridge (<NUM>) comprising a fuel for refuelling said fuel cell;
wherein said refuelling unit (<NUM>) is configured to receive through said waste inlet (<NUM>) a waste fluid stored in a fuel reservoir of a fuel cell connected to said fuel cell receiving section, said refuelling unit (<NUM>) further comprises an intermediate fuel reservoir (<NUM>) for storing fuel, said intermediate fuel reservoir (<NUM>) being fluidly connected to said fuel inlet (<NUM>) of said cartridge receiving section (<NUM>) and said fuel outlet (<NUM>) of said fuel cell receiving section, wherein said refuelling unit (<NUM>) is configured to firstly receive in said intermediate fuel reservoir (<NUM>) a predetermined amount of fuel from a cartridge (<NUM>) connected to said cartridge receiving section (<NUM>) and secondly empty said intermediate fuel reservoir (<NUM>) and guide said fuel stored therein out of said fuel outlet (<NUM>) of said fuel cell receiving section (<NUM>) and into the fuel reservoir (<NUM>) of a fuel cell (<NUM>) connected to said fuel cell receiving section (<NUM>), characterized in that said refueling unit (<NUM>) further comprises a first piston (<NUM>) and an actuator (<NUM>), wherein said first piston (<NUM>) is configured to be movable in said intermediate fuel reservoir (<NUM>) between a first position and a second position, said refuelling unit (<NUM>) being configured to receive in said intermediate fuel reservoir (<NUM>) a predetermined amount of fuel from a cartridge (<NUM>) connected to said cartridge receiving section (<NUM>) by moving said first piston (<NUM>) from said first position to said second position using said actuator (<NUM>), and secondly empty said intermediate fuel reservoir (<NUM>) and guide said fuel stored therein out of said fuel outlet (<NUM>) of said fuel cell receiving section (<NUM>) by moving said first piston (<NUM>) from said second position to said first position using said actuator (<NUM>).