Patent Application
20150295287
This application claims priority to German Patent Application No. 10 2014 206 861.4, filed Apr. 9, 2014, the contents of which are hereby incorporated by reference in their entirety.
The invention relates to a temperature control device for an electrical energy supply unit and a temperature control arrangement with a temperature control device. The invention furthermore relates to a temperature control arrangement with such a temperature control device. The invention further relates to a motor vehicle with such a temperature control arrangement.
Rechargeable battery systems for electric vehicles with a purely electric drive and for hybrid vehicles and vehicles with fuel cell drive are the subject of current research. At present, in the named types of vehicle, lithium-ion batteries are preferably used, which are distinguished by a high energy density and an only weakly distinct memory effect. The capability of a rechargeable battery to supply various electric consumers installed in motor vehicles reliably with electrical energy depends to a considerable extent on the thermal conditions prevailing in the environment of the battery. This is because both the electrochemical processes occurring in the battery in the providing and also in the receiving of electrical energy—in the sense of recharging—are dependent to a not insignificant extent on the operating temperature of the battery. Of significant importance for an undisturbed operation of said batteries—this applies not only to said lithium-ion-based batteries, but generally to any rechargeable battery systems—is the creation of thermally well-defined environmental conditions. This means directly with regard to the considerable temperature fluctuations occurring in a motor vehicle during normal operation, that these must be balanced out thermally by suitable temperature control devices coupled thermally with the battery, in order to be able to keep the environmental temperature of the battery and hence also the temperature of the battery itself within a predetermined temperature interval.
The term “temperature control device” is understood to mean here in the present context any device which is able to reduce the current temperature of the battery unit which is to be temperature-controlled—in this case the temperature control device follows the operating principle of a cooling device—or to increase it. In the latter case, the temperature device acts as a heating device.
Modern temperature control devices are often constructed in the form of heat exchangers which have cooling plates which are able to be flowed through by a coolant. The battery units which are to be cooled are mounted in a planar manner onto said cooling plates and are thereby thermally coupled with the coolant. In order to now realize not only a cooling function, but also a heating function, such heat exchangers are often also provided with electric heating elements, for instance in the manner of PTC heating components, which can be electrically operated and heated. By suitable mounting of the heating elements, for instance in the manner of a sandwich between battery units and cooling plates or, alternatively thereto, in recesses provided on the cooling plates, the thermal contact between the battery units and the heating elements necessary for heating the battery units can be produced. A heat exchanger with cooling tubes for cooling a battery, but without integrated heating function, is described for instance in DE 10 2011 079 091 A1.
However, in such temperature control devices with integrated electric heating elements it proves to be problematic that the electric heating elements are typically produced from an electrically conductive material such as e.g. a metal and consequently require an electrical insulation with respect to the battery units which are to be heated.
Against this background, DE 10 2011 084 002 A1 describes a thermal transfer device which is arranged between a battery and a temperature control plate and is constructed in a layered manner with at least two layers. One of the layers, the so-called thermal insulation layer, serves here for the setting of a thermal resistance between battery and temperature control plate, a further layer, on the other hand, serves as a so-called tolerance compensation layer, by means of which locally different thicknesses of the thermal insulation layer can be compensated.
Against this background, electrical insulations in the form of plastic films or coatings of silicone are known from the prior art. However, the application of such layers generally entails considerable production expenditure, which has the effect of increasing the cost of the manufacturing process of the temperature control devices.
It is therefore an object of the present invention to create an improved temperature control device for the temperature control of an electrical energy supply unit, in particular a rechargeable battery.
The said object is solved by the subject of the independent claims. Preferred embodiments are the subject of the dependent claims.
The basic idea of the invention is accordingly to produce from a fibre composite plastic a temperature control device which is able to be flowed through by a coolant or heating medium. Such a fibre composite plastic—also known in specialist circles in the field of materials science as fibre plastic composite (FPC) or fibre-reinforced plastic—comprises reinforcement fibres which are embedded into a plastic matrix and are bonded to the plastic of the matrix by adhesive or cohesive forces. Such a combination of fibres and plastic matrix produces a layer material which has a high stability and, moreover, has the desired thermal and electrical characteristics—i.e. high thermal conductivity and electrical insulation. A fibre composite plastic is therefore excellently suited for the configuration of a fluid channel, in particular a fluid duct, for example in the manner of a fluid tube, for a fluid acting as heating medium or coolant. Such a fluid duct constitutes the central component of the temperature control device which is presented here. In addition, the plastic matrix presented here makes superfluous the additional provision of an electrical insulation, for instance in the form of an insulation layer of a plastic, as was mostly necessary hitherto in temperature control devices made of metallic fluid pipes, in order to insulate these electrically with respect to the metallic housing of the battery which is to be cooled, because such an electrical insulation is contained in the delimiting element in the temperature control device according to the invention.
A temperature control device according to the invention comprises a first delimiting element, which has at least a first layer of a fibre composite plastic. The temperature control device furthermore comprises a second delimiting element, which comprises at least a second layer of the fibre composite plastic and is mounted on the first delimiting element such that the two delimiting elements form a fluid duct for through-flowing by a fluid. It shall be understood that the said fluid duct can be composed not only of two delimiting elements, but also of a greater number of such delimiting elements. A delimiting element can, in turn, comprise several layers, as is to be discussed in further detail below.
An embodiment may be considered to be particularly advantageous, because it is simply constructed and therefore entails particularly low manufacturing costs, in which the first delimiting element consists of the first layer of the fibre composite plastic and the second delimiting element consists of the second layer of the fibre composite plastic. In other words, the two delimiting elements are formed respectively exclusively from the first or respectively second layer of the fibre composite plastic, i.e. no further layers are present.
Particularly expediently, the temperature control device can be constructed as a flat tube. In this way, the structural space required for the temperature control device can be kept relatively small. Furthermore, by means of such a plate-like construction, a planar and hence thermally highly effective contact can be produced with the component which is to be temperature-controlled, for example a battery which typically likewise comprises a housing part constructed in a plate-like manner. In a plate-like construction, connected therewith, of the delimiting elements, in a particularly preferred variant a matrix layer of a thermoplast can be provided respectively on the sides, facing one another, of the plate-like delimiting elements. This facilitates the shaping of the two delimiting elements and their fastening to one another.
A construction of the temperature control device which is mechanically stable and which is fluid-tight, necessary at the same time for the construction of the duct, can be achieved by the two delimiting elements being fastened to one another by means of their respective edge sections by means of a form-fitting or materially bonded connection. Form-fitting connections can be produced here by means of clipping, materially bonded connections by means of welding, in particular by means of hot gas welding, laser welding or friction welding.
In a particularly preferred embodiment, the fibres of the fibre composite plastic extend substantially along a shared direction of extent. This can be advantageous, if at least individual fibres—which will be explained in further detail below—are constructed so as to be electrically conductive and can be connected with an external energy supply unit, so that the functionality of a heating device is already integrated into said layer. Alternatively thereto, at least two, preferably even a plurality, particularly preferably even all fibres can extend along different directions of extent. Such an arrangement of the individual fibres is aimed at establishing the stability of the layer on loading under tension in an application-specific manner, and namely not only along a particular preferred direction, but rather independently of the direction of load.
Various material systems come into consideration as fibre material for the fibres embedded into the plastic matrix. The use of glass fibres, carbon fibres, aramid fibres and/or natural fibres is particularly recommended.
In order to now integrate the functionality of a heating device into the temperature control device which is presented here, it is proposed to use an electrically conductive material as fibre material for the fibres, so that at least one fibre of the fibre plastic composite is able to conduct electric current and/or heat. The already mentioned fibres of carbon come into consideration for this, but also metallic fibres, for instance of aluminium or copper. When the said electrically and/or thermally conductive fibres are connected on the end side via suitable electrical connections with an external electrical energy source or respectively with a suitable heat source, for instance a so-called electric auxiliary heater, the electric current flow or respectively the flow of heat through the fibres leads to a heating of the fibres, the plastic matrix and consequently also the entire first or respectively second layer of the temperature control device. In this case, the layer of the fibre composite plastic follows the operating principle of a heating device.
Alternatively or additionally, at least one of the fibres can be constructed in a thermally conductive manner, i.e. fibre materials with high thermal conductivity are selected, whereby the thermal coupling of the fluid flowing through the fluid duct to the component which is to be heated or cooled can be significantly improved.
Alternatively to the procedure, explained above, of implementing a heating function directly into the original fibres of the fibre plastic composite, an embodiment may also be considered to be advantageous in which the layer of the fibre plastic composite is additionally provided with an electric heating element for heating the temperature control device. Such a heating element can be formed for instance in the form of several heating wires or of at least one electrically conductive heating band, for example of a metal. In this case also the electric connection to an electrical energy source can take place via an end-side contacting of the heating wires or respectively heating bands. In a further alternative scenario to the previous one, an electrically conductive lacquer layer can also be applied on the layer of the fibre plastic composite, by means of which the desired heating function is brought about. Alternatively or additionally to the said heating bands/heating wires, one or more electric heating resistors, for instance in the manner of PTC elements, can be integrated into the fibre plastic composite.
In a particularly preferred embodiment, the heating wires and/or the at least one electrically conductive heating band can be constructed as an electric heating coil, such that an electric heating current is able to be induced in them by means of electromagnetic induction. In this way, a heating current can be generated in the heating wires or respectively in the heating band, i.e. no external electric connection elements are necessary.
In another preferred embodiment, an electrically conductive lacquer layer can also be applied on the layer of the fibre plastic composite, by means of which lacquer layer the desired heating function is brought about.
Of course, the temperature control device which is presented here can be expanded in the scope of structural configuration to forms of realization with two or more layers, which are then arranged on one another in the sense of a multi-layered structure. Each layer can be provided here with an individual functionality; for instance, it is conceivable to equip one layer in a completely electrically insulating manner with non-conductive fibres such as glass fibres or natural fibres and to arrange thereon a further layer which—as explained above—is penetrated by electrically conductive heating wires. Therefore, a variety of possibilities open up for the relevant specialist in the art for adapting the temperature control device according to the invention to different requirements.
If the first and/or second delimiting element, as discussed above, is composed of several individual layers which are layered on one another along a layer direction, the provision of a barrier layer is recommended. This can either be arranged between two adjacent layers, in order to ensure the diffusion tightness of the individual layers with respect to one another, or can be directed outwards as a so-called external barrier layer. Such a barrier layer can be realized for instance in the form of a composite film which in turn comprises a metal layer. Alternatively, a plastic film or a metal film is also conceivable, which has the desired characteristics with regard to the necessary tightness. By means of such a barrier layer, an undesired diffusion of the coolant or respectively heating medium through the delimiting elements can be effectively prevented.
Further layers possibly arranged on the layer of the fibre composite plastic, for instance the already presented barrier layer and/or the likewise already explained lacquer layer, can, since they can have different material characteristics in general and different coefficients of thermal expansion in particular, lead to a warping in the layer of the fibre composite plastic. In order to prevent this, it is recommended to provide a matrix layer of a thermoplast on both sides of a respective plate-like delimiting element. Warping effects possibly occurring on one side of the delimiting element are balanced out in this way and in an ideal case are completely compensated.
The invention furthermore relates to a temperature control arrangement with at least one energy supply unit, preferably a rechargeable battery, most preferably a lithium-ion battery. The energy supply unit is coupled here thermally with the previously presented temperature control device.
The invention further relates to a motor vehicle with at least one previously presented temperature control arrangement.
Further important features and advantages of the invention will emerge from the subclaims, from the drawings and from the associated figure description with the aid of the drawings.
It shall be understood that the features mentioned above and to be further explained below are able to be used not only in the respectively indicated combination, but also in other combinations or in isolation, without departing from the scope of the present invention.
Preferred example embodiments of the invention are illustrated in the drawings and are explained in further detail in the following description, wherein identical reference numbers refer to identical or similar or functionally identical components.
There are shown, respectively diagrammatically:
The fibre composite plastic comprises reinforcement fibres 7, which are embedded into a thermoplastic plastic matrix 6 and are bonded by adhesive or cohesive forces to the plastic of the matrix 6. The reinforcement fibres 7 are indicated only diagrammatically in the figures. The thermoplastic plastic matrix 6 renders superfluous the additional provision of an electrical insulation, for instance in the form of an insulation layer of a plastic, such as was mostly necessary hitherto in temperature control devices made of metallic fluid pipes, in order to insulate these electrically with respect to the metallic housing of the battery which is to be cooled, because such an electrical insulation is already integrated into the delimiting element 2a in the temperature control device 1 according to the invention. This is advantageous particularly when electrically conductive fibres are to be integrated into the matrix 6, as will be explained below in more detail.
In addition, the temperature control device 1 comprises at least a second delimiting element 2b, which in turn comprises at least second layer 3b of the fibre composite plastic. The two delimiting elements 2a, 2b are mounted on one another here such that they form a fluid duct 4 for flowing through by a fluid, in which they at least partially delimit this with respect to the environment U of the temperature control device 1. In other words, the delimiting elements 2a, 2b enclose the fluid duct 4 with respect to the environment U in a fluid-tight manner. In the example scenario of
Different material systems can be selected for the fibres 7 embedded into the plastic matrix 6 of the first or respectively second layer 3a, 3b. For instance, glass fibres, carbon fibres, aramid fibres or natural fibres and a combination of two or more types of fibre come into consideration.
It is of course familiar to the relevant specialist in the art that for delimiting the fluid duct in addition to the two delimiting elements 2a, 2b further supplementary delimiting elements, not illustrated explicitly in
In a variant not shown in the figures, the two delimiting elements 2a, 2b can also consist exclusively of the first or respectively second layer 3a, 3b of the fibre composite plastic, i.e. the delimiting elements 2a, 2b have no further components. Alternatively thereto, the delimiting elements 2a, 2b shown in
In the arrangement shown in
In the shell-like construction of the delimiting elements 2a, 2b shown in the figures, a matrix layer of a thermoplast (not shown) can be provided on the sides of the plate-like delimiting elements 2a, 2b facing one another. This facilitates the fastening of the two delimiting elements 2a, 2b to one another, in particular by means of the named methods, i.e. friction welding or laser welding. The same applies to the case of a form-fitting connection such as the already mentioned clip connection.
The functionality of a heating device can be optionally integrated into the temperature control device 1, by an electrically conductive material being used as fibre material for the fibres 7. Once again, the already mentioned fibres 7 of carbon come into consideration for this, alternatively also, however, metallic fibres, for instance of aluminium or copper. When electrically conductive fibres 7 are connected on the end side via suitable electric connections (not shown) with an external electrical energy source, the electric current flow through the fibres 7 leads to a heating of the fibres 7, the plastic matrix 6 and consequently also the entire first or respectively second layer 3a, 3b of the delimiting elements 2a. In a variant, it is also conceivable to connect said fibres 7 not with an electrical energy source, but with a heat source. Such a heat source can be, for instance, an electric auxiliary heater.
The fibres 7 can also be constructed so as to be thermally highly conductive, whereby the thermal coupling of the fluid flowing through the fluid duct 4 to the component which is to be temperature-controlled can be considerably improved.
Alternatively to the previously explained procedure of implementing a heating function directly into the original fibres 7 of the fibre plastic composite, the first and/or second layer 3a, 3b of the fibre plastic composite can be additionally provided with an electric heating element 16 for heating the temperature control device 1. Such a heating element 16 can be realized for instance in the form of several heating wires 8 or at least one electrically conductive heating band 9, for example of a metal, which is shown diagrammatically in the illustration of
Finally,
It is clear that the delimiting elements 2a, 2b of the temperature control device 1 presented here can be expanded within structural modifications to forms of realization with two or more layers, so that the delimiting elements 2a, 2b are formed having several layers. Each layer can then be provided with an individual functionality: for instance, it is conceivable to equip a layer in a completely electrically insulating manner with natural fibres, and to arrange on the latter a further layer, which—as shown in FIG. 2—is penetrated by electrically conductive heating wires 8. Therefore, a variety of possibilities open up for the specialist in the art for adapting the temperature control device 1 according to the invention to different requirements. By way of example, such a multi-layered structure is illustrated in
When the first and/or second delimiting element 2a, 2b is composed, as explained above, of several individual layers which are layered on one another along a layer direction, the provision of a barrier layer between two adjacent layers is recommended, in order to ensure the diffusion tightness of the individual layers with respect to one another (not shown). Such a barrier layer can be realized for instance in the form of a composite film, which in turn comprises a metal layer. Alternatively, a plastic film is also conceivable, which has the desired characteristics with regard to the necessary tightness. By means of such a barrier layer, an undesired diffusion of the coolant or respectively heating medium through the delimiting elements is prevented.
In conclusion, looking again at
| Number | Date | Country | Kind |
|---|---|---|---|
| 102014206861.4 | Apr 2014 | DE | national |
