This application claims priority to German Patent Application DE 10 2004 005 394.4, filed Feb. 4, 2004, which is hereby incorporated by reference herein.
The present invention is directed to an electrochemical energy store.
An electrochemical energy store of a type relevant to the present invention is described in WO 02/07249 A1. A development of this type of energy store is also described in German Application P 102 382 35.2. With regard to further prior art, reference should be made to EP 065 349 B1 and DE 198 49 491 C1. The German reference DE 197 27 337 C1 describes a venting closure for electrical housings.
The prior art has the disadvantage of a relatively complicated design of the electrochemical energy store, with a large number of modules and storage units, and heat exchange units which are in each case arranged between them. The energy store together with the individual modules is assembled in a battery box to which the entire unit is fitted. Owing to the installation of the individual modules and of the heat exchange units, the construction process and the overall installation in the battery box are very difficult. For example, it has been found that the connection of the individual storage cells and channels in the heat exchange units is often highly dangerous and difficult, owing to the high potential of the modules. In this case, screw connections for the connections of the individual parts, for example of the storage cells, must, inter alia, be tightened to a defined torque, which is frequently inconvenient and difficult owing to access and space restrictions.
In order to make it possible to carry out the assembly work with an at least reasonably acceptable amount of effort, mounting openings are frequently provided on the battery box. However, mounting openings such as these are problematic for fire protection reasons and for EMC protection (electromagnetic radiation). Accordingly, the battery box is generally manufactured from sheet steel, and it must be designed to be very robust, owing to the heavy weight of the energy store.
The present invention provides an energy store having a structure arranged and configured to facilitate a simplified installation in a battery box.
In a preferred embodiment of the present invention an electrochemical store comprises a plurality of heat exchange units and a plurality of electrochemical storage cells arranged in an array, alongside one another, and between pairs of the heat exchange unit. The heat exchange units include heat exchange channels for flow of a temperature control fluid. A forward flow distribution channel is coupled to the heat exchange channels for ingress of the temperature control fluid and a return flow distribution channel is coupled to the heat exchange channels for egress of the temperature control fluid flow. Pursuant to a feature of the present invention, the plurality of heat exchange units are coupled to one another to form a self-supporting electrochemical store unit suitable for insertion into a battery box as a unit.
FIGS. 1 to 5 show the general design features of an electrochemical energy store. Since such an electrochemical energy store is, in general, known from the prior art, only the major parts will be described in more detail in the following text. In principle, the energy store may be designed as required by a respective application. However, according to a feature of the present invention, the energy store is designed as a self-supporting unit, as will be described in more detail in the following text.
A plurality of heat exchange cooling units 1, between which storage cells 2, for example Ni/MeH cells, are arranged, is provided in the energy store (see, for example,
As can be seen in
Referring now to FIGS. 6 to 19, there is illustrated a design for an energy store in accordance with a feature of the present invention. As shown, the heat exchange units 1 and the energy storage cells 2 are assembled in the form of a self-supporting unit. Pursuant to an exemplary embodiment of the present invention, a support housing 12 is used to provide a self-support structure for the energy store, with a lower support pressure plate mount 13 on the lower face, an upper support pressure plate 14 on the upper face, and two side support clamping plates 15 and 16, as shown, for example, in
Since the energy store according to the exemplary embodiment of the present invention is in the form of a self-supporting unit, the individual modules, in particular the storage cells, and the heat exchange units which are arranged between each of the storage cells, can be installed and assembled with the support housing outside the battery box. After final assembly, the entire self-supporting unit can then be inserted into any desired battery box.
It is also advantageous that the battery box may then form the necessary fire and EMC protection, and may be designed to be sealed appropriately for this purpose. Furthermore, there is no longer a need to design the battery box as a mechanism to support the now self-supporting energy store. Thus, according to the present invention, a battery box can be fabricated with less and lighter materials and will therefore be of lighter construction, and be less expansive to manufacture.
The self-supporting energy store according to the present invention may be used in a vehicle, or else for any other application. If it is installed in a vehicle, it can be installed in the existing spare wheel well. In the case of a new development, the required physical space could be provided, for example, in the bottom structure of the vehicle.
In order to secure cooling units 8, 9 (
The elongated holes 18 allow the cooling unit 8, 9 together with the circulation distribution channels 4, 5, which are subject to temperature fluctuations, to expand in the y direction, so that no stresses occur.
The lower support pressure plate mount 13 has clamping grooves 19 and 20 at the ends. The clamping grooves 19 and 20 are used to uniformly absorb a defined clamping force from the side support clamping plates 15 and 16 (see the detail Y in
At the sides, the lower support pressure plate mount 13 is provided with threaded holes 23, via which the side support clamping plates 15 and 16 are attached, by means of corresponding, inserted screws.
The upper support pressure plate 14 also has a curved, radius contour 24, which, as in the case of the lower pressure plate 13, is matched to the radius contour of the associated heat exchange channels 3, and centers them appropriately. On the sides, the upper support pressure plate 14 has clamping grooves 25 at the ends. The clamping grooves 25 likewise are used to absorb a defined pressure force uniformly via the side support clamping plates 15 and 16 (see the detail X and the enlarged illustration in
The side support clamping plates 15 and 16 each have a number of openings 26, whose diameters are matched to the cells 2 and to the supply line parts and distribution lines for the heat exchange units. The cells 2 are secured against rotation by means of the quadrilateral openings which are shown. They are secured against rotation because the cells 2 must be tightened with a defined torque, for coupling to corresponding connectors.
The side support clamping plates 15 and 16 also have clamping frames 27, 28, 29 and 30, which absorb the defined pressure force from the support lower pressure plate 13 and from the upper support pressure plate 14.
FIGS. 13 to 15 show the assembly and design of an energy store according to an exemplary embodiment of the present invention, including a plurality of heat exchange units 1 of the type illustrated in
The cells 2 are inserted into the cooling unit 8, as shown in
After the stack of layers of cooling unit 8, 9 and energy storage cells or modules 2 are aligned in their positions, the upper support pressure plate 14 is installed at the top of the layers (see
When the upper support pressure plate 14 is installed and aligned with the defined pressure force, the side support clamping plates 15 and 16 are inserted with their clamping frames 27 to 30 into the clamping grooves 25 on the lower support pressure plate 13, and with the upper support pressure plate 14 and the clamping grooves 25, and are screwed to the lower support pressure plate mount 13 and to the upper support pressure plate 14 for fixing in the x direction. It is also possible, of course, particularly when relatively large quantities are involved, to weld the parts mentioned above to one another.
Four centering bolts 40 (only one of which is illustrated) are located on the battery box 38, so as to hold the self-supporting energy store with the support housing 12 in the centering holes 21 which are provided there, and thus, as described, to fix the energy store in the horizontal direction, with the shear forces being absorbed via the centering holes 21 and the centering bolts 40. The battery box 38 is screwed to the energy store via the threaded holes 22 which are incorporated in it, by means of attachment screws 41 in the battery box 38.
FIGS. 20 to 26 show a water outlet and venting screw 42 with a water outlet and venting disc 43, for use as a water outlet and venting device for the battery box 38. In this case,
On the basis of the applicable regulations, an enclosure for the energy store, such as the battery box 38, must ensure fire protection up to 900° C. in the event of fire. Furthermore, the electronic components which are required for the connection of the individual modules and/or memory cells and/or storage cells must be protected against electromagnetic radiation (EMC). For this reason, a battery box is generally manufactured from thin-walled steel plate sheet steel, in which case the cover should be watertight and should likewise be sealed with an EMC shield. The use of a support structure according to the exemplary embodiment of present invention makes it possible to comply with these regulations.
However, there is a problem on the one hand in that temperature differences result in pressure building up in the battery box 38 when the battery box 38 has a watertight seal. This build up in pressure should be equalized.
On the other hand, there is always a risk of heat exchange units leaking, and of the cooling liquid, generally water, being able to emerge. This can lead to damage to electronic components. In particular, major damage can occur in the electronics and in the electrical system since the connections of the modules are subject to high voltages and may be damaged when cooling liquid emerges.
One advantageous embodiment of the present invention provides a pressure-tight and water-tight battery box being having at least one water outlet and venting device of the type illustrated in
The water outlet and venting device according to the exemplary embodiment of the present invention not only allows pressure equalization but also, if necessary, allows any liquid which emerges from the heat exchange units to be passed into free space, so that no damage occurs to the electronic components or to the modules. The venting device may, of course, act in both directions; that is to say, if the pressure in the interior of the battery box is lower than the outside pressure, pressure equalization with the environment is likewise possible.
The water outlet and venting screw 42 has a blind hole 46 (see
The water outlet groove 48 may also be incorporated into the water outlet and venting disc 43 instead of the water outlet and venting screw 42. In the same way, the water outlet and venting disc 43 may be arranged on the outside, and the water outlet and venting screw 42 on the inside of the battery box 38. The water outlet and venting disc 43 can be welded to the battery box 38, or connected to the battery box 38 in any other desired manner.
The water outlet and venting screw 42 thus not only provides ventilation and venting for the battery box 38, but also an outlet for hydrogen to dissipate from the cells, if this emerges. The cooling liquid is likewise passed directly into free space outside of the battery box 38 in the event of any leaks in the heat exchange units.
In addition,
The cooling circuit, which is known per se, ensures optimum filling and venting of the entire cooling circuit. The venting in this case takes place via the return flow from the battery box 38 directly through the line to the equalization container 52. The supply air for the external cooling circuit is not supplied directly between the vehicle floor and the roadway, but from the interior venting, which is normally passed into free space at the side on the left and right, as forced venting. This outlet can be supplied to the external cooling circuit.
A direct supply of supply air from the area under the floor and from the roadway to the external cooling circuit would have the disadvantage that this air would have been heated by radiation heat emitted from the engine and, when the outside temperatures are very high, additionally by roadway heat from the roadway area as well. When the outside temperatures are very high, this could result in the battery not being cooled sufficiently, and, on the contrary, it would even be heated. In addition, a supply air channel can also be provided from the vehicle ventilation system for the outlet air from the interior ventilation, carrying air which has been cooled by the air-conditioning system or has been heated by the engine heat to the external cooling circuit. This allows the battery to be optimally cooled not only when the outside temperatures are very high, but also when they are very low.
When the outside temperatures are very low, this embodiment has a further advantage, specifically in that the battery is not cooled, but is heated by the engine heat, which in fact heats the interior, with box 38. The return flow from the battery box 38 passes via a connection 56 to the equalization container 52.
A further option for the external cooling circuit would be a direct link to the air-conditioning system. In this case, the external cooling circuit would be replaced.
In this embodiment, the cooling components, such as the cooling components holder 57, are omitted, as are the heat exchange 58 and the expansion valve 59. The cooling circuit initially passes from the equalization container 52 directly via the water pump 60 into the interior of the battery box 38 to the heat exchange units, and from there back again to the equalization container 52. For cooling at high outside temperatures, the cooling line 62 is passed from an air-conditioning compressor (not illustrated) in a spiral shape through the equalization container 52, and is then passed back again to the air-conditioning compressor.
Since additional external cooling is required for battery cooling only in high outside temperatures, and the air-conditioning system is in operation in this situation in any case, the refinement as described above is a cost-effective and simple solution. No additional external cooling would be required for cooling the battery at temperatures, for example, below 20° C.
In the preceding specification, the invention has been described with reference to specific exemplary embodiments and examples thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the invention as set forth in the claims that follow. The specification and drawings are accordingly to be regarded in an illustrative manner rather than a restrictive sense.
Number | Date | Country | Kind |
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10 2004 005 394.4 | Feb 2004 | DE | national |