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1. WO2008022709 - DEVICE FOR DRIVING A FUEL CELL VEHICLE

Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

[ EN ]

Device for driving a fuel cell vehicle

The invention relates to a device for driving a vehicle which comprises an electrical drive motor and a fuel cell providing the electrical power.

It is known from EP 1 266 783 Bl to decouple the fuel cell and the drive motor by suitable vibration dampers in a vehicle which is driven by a fuel cell system. The flexible electrical connections which are required between the fuel cell, the drive motor and optionally the converter have proved to be disadvantageous in such structures, in
particular due to the very high currents and/or voltages involved. Adequate reliability of the connections entails highly complex production and installation methods, as stringent requirements apply to flexibility, watertightness and electromagnetic compatibility (EMC) .

The object of the invention is to provide a simple, compact structure which can be constructed inexpensively and
reliably and which permits simple installation.

According to the invention, said object has been achieved with the features stated in the characterising part of Claim According to the invention, the fuel cell and the electrical drive motor are integrated into a single unit and firmly-joined together. In contrast with the prior art, firmly means in this case not decoupled, thus for example joined by a direct screw joint, for example to a common supporting structure .

The advantages of such integration of fuel cell and drive motor as a unit reduces the costs, mass and volume of the unit. Moreover, previous systems have required complex and thus costly cables and connectors for providing in
particular electrical connection between the fuel cell and drive motor, in particular also in order to ensure
electromagnetic compatibility (EMC) . Such cables and
connectors may be dispensed with thanks to integration as a unit. In addition to the advantages with regard to costs and installation space, dispensing with connections and cabling which must be constructed flexibly means that reliability may be increased.

Furthermore, integration as a unit also permits improved, lighter, faster and thus also more inexpensive installation. Integration as a unit may readily be achieved by preassembly outside the vehicle. The preassembled unit may then simply be installed in the vehicle, for example in the engine compartment instead of the previous combustion engine, and then connected with the drive shafts, media supplies etc..

The centralized location of system masses in the integrated unit has a positive impact on acoustic characteristics and more effective damping of the overall unit may be provided.

The structure according to the invention thus also enables advantages in the efficient implementation of NVH (= noise, vibration, harshness) measures.

Further advantageous developments are revealed by the remaining subclaims and by the exemplary embodiment
described in greater detail below with reference to the drawing.

In the drawing, the single figure shows a schematic three-dimensional representation of a drive device according to the invention in an exemplary embodiment .

The figure shows a drive device 1 which comprises two fuel cells or fuel cell stacks 2 arranged in a V relative to one another which are arranged and fastened on a common joining element 3. The V-shaped arrangement is here selected purely by way of example. Any other conceivable arrangements of one or more fuel cells or fuel cell stacks 2 are, of course, also possible for the purposes of the invention. Peripheral units 4 (in this case for example a turbocompressor for supplying air to the fuel cells) for operation of the fuel cells 2 are arranged between the fuel cells 2, thus in this case in the interspace formed by the V-shaped arrangement.

In addition, an electrical drive motor 5, electronic
components 6, taking the form of a common electronics unit and substantially comprising a converter and peripheral components, together with further peripheral units 4 for the fuel cells 2 are arranged beneath the joining element 3. The peripheral units 4 form, together with the fuel cells 2, a fuel cell system which, when appropriately connected to air and hydrogen lines, supplies electrical energy.

The drive device 1 here forms an integrated unit in which all the components, but in particular the electrical drive motor 5 and the fuel cells 2, which here supply power, are firmly joined together. In principle, this may be achieved by means of any desired supporting structure, or, as here in the case of self-supporting individual components, by means of the joining element 3.

Integrating the fuel cell system 2, 4 and drive motor 5 as a unit 1 reduces the number of detachable interfaces, since all that need be produced here between the integrated drive device 1 and the vehicle are connections for coolant and hydrogen and the connection to an air filter. In particular in the fault-prone electrical area, cable routing is
simplified and cable lengths are greatly shortened. This ensures the shortest possible transmission paths for the current from the fuel cells 2 to the electrical drive 5. In addition, technically complex electrical components, such as for current distribution, are omitted or are greatly
simplified by integration into the unit 1. The complex flexible cabling with plug connectors needed due to the required electromagnetic compatibility and watertightness may also be omitted. As a result, costs are appreciably reduced and reliability is increased. At the same time, mass and volume may additionally be distinctly reduced.

In addition to integration of the peripheral units 4 for the fuel cells 2 in the drive device or unit 1, it is possible also to provide therein in particular current carrying means which may for example take the form of copper bars 7 taking the shortest path from the fuel cells 2 to a commonly used electronic unit 6 in which are located, if necessary, galvanic disconnecting switches and the electronics for actuation of the electrical vehicle drive. The commonly used electronic components 6 may here furthermore comprise open-and closed-loop control and power electronics for the peripheral units and/or a necessary sensor system. The detachable connections of the current-carrying components (copper bars or cables) may here be accommodated within this electronic unit 6. As a result, watertightness and EMC may be achieved distinctly more straightforwardly. In addition, many complex and costly interfaces in the high voltage cabling and piping are omitted.

The preferred embodiment here provides preassembling the fuel cell system 2, 4 and the electrical drive 5 together with integrated electronic components 6 on a common
supporting structure 3 and suspending the entire
preassembled unit 1 in the vehicle (not shown) in
oscillating manner. For example, the unit 1 may in principle be installed in oscillating manner in a previous engine compartment of a vehicle instead of the combustion engine on the engine mounts thereof before being connected to the drive shafts (universal joint or half shafts) , to the hydrogen supply from a reservoir or an on-board gas
generation system and to an air filter and optionally to an exhaust gas system.