DE102009058842B4 - Vehicle with temperature control device, battery with latent heat storage and method for temperature control of vehicles - Google Patents

Abstract

Vehicle (11) with at least one battery (1) and at least one passenger compartment (9) and with at least one temperature control device, wherein the temperature control device has at least one phase change material (2) that is connected to a passenger compartment (9) of the vehicle (11) and to a battery (1) of the vehicle (11) is thermally coupled so that heat can be exchanged between them, characterized in that the temperature control device has at least two of the phase change materials, one of the phase change materials (3) being mixed and/or emulsified in the other of the phase change materials (2). and the phase change material (3) mixed or emulsified in the other phase change material (2) is microencapsulated by means of a plastic encapsulation to form capsules with a diameter ≤ 30 µm and/or ≥ 2 µm.

Description

The invention relates to a method for controlling the temperature of a vehicle, in particular its passenger compartment and battery, as well as an appropriately temperature-controlled battery and a correspondingly temperature-controlled vehicle.

Electrically powered vehicles in particular pose a number of temperature control problems. On the one hand, it is necessary here for the battery to be kept at a certain temperature so that it can deliver optimal efficiency. In addition, the temperature control of the passenger compartment is difficult, since compared to vehicles with a pure drive via combustion engines, only a small amount of waste heat is generated. Particularly in winter, therefore, there is not enough heat available for heating the passenger compartment in electrically powered vehicles.

The following approaches to regulating the temperature are known from the prior art: On the one hand, heating with fossil fuels can be used, such as in parking heaters. However, this solution has the disadvantage that it worsens the environmental balance of the vehicle.

A further solution consists in drawing electrical energy for heating from the electrochemical energy store, ie the battery, which, however, has the disadvantage that the range of the vehicle is significantly reduced as a result.

The usual air conditioning systems, which are based on a compressor, condenser and evaporator, are known for cooling the passenger compartment. Since these systems consume energy, they also significantly reduce the range of an electrically powered vehicle.

From the DE 42 30 583 A1 a temperature control device according to the preamble of patent claim 1 is known.

In the FR 28 95 838 A1 describes an electric battery that includes a phase change material for cooling or heating the battery.

the JP H06 096 343 A describes a thermal storage device for a sales facility or a container, so that goods in a supermarket can be heated or cooled.

In the DE 41 41 811 C1 describes a drive battery of an electric vehicle that can be used as a heat store for heating a vehicle interior.

From the JP H08 222 280 A discloses a plurality of electrically connected cells arranged within a casing, the casing being filled with ceramic granules having a high heat capacity.

In the DE 10 2009 050 510 A1 describes a tempering element that can have different phase transition materials with different phase transition temperatures.

It is an object of the present invention to specify a thermal coupling between a battery and a passenger compartment of a vehicle, which has increased thermal storage with reduced response times.

This object is achieved by a vehicle according to claim 1, a method for temperature control of a passenger compartment and a battery of a vehicle according to claim 5 and a battery of a vehicle according to claim 7.

According to the invention, it was recognized that phase change materials in latent heat stores are particularly suitable for solving temperature control tasks in electric vehicles.

A latent heat accumulator (latere (lat.) hide), hereinafter also referred to as latent accumulator, stores thermal energy by changing the physical state of a storage medium. Such media for energy storage are also referred to as "phase change materials" (English phase change material, PCM).

These phase change materials include, for example, paraffins, also known as the material for candles, which absorb (load) a great deal of thermal energy when melting, which they can release (discharge) again when solidifying. Some salts, such as nitrate salts, behave similarly.

When heat is stored in the storage material, the material begins to change its phase, for example to melt, when the temperature of the phase transition is reached, and then, despite further storage of heat, does not increase its temperature until the material has completely changed phase. Only then does the temperature rise again. Since there is no noticeable increase in temperature for a long time despite the addition of heat, the heat stored during the phase transition is called "hidden heat" or "latent heat". Latent heat accumulators have a correspondingly high heat capacity per volume unit.

According to the invention, regulation of the temperature of a battery of a vehicle and/or a passenger compartment of such a vehicle is achieved through the use of such phase change materials.

First of all, the function for temperature control of a battery in a vehicle is to be described. Here, at least two phase change materials are placed in thermal contact with the battery. Thermal contact here means that heat can get from the battery to the latent heat storage device and from the latent heat storage device to the battery. A thermal contact can be established in particular via thermally conductive materials. The phase change materials are in the form of a mixture or an emulsion. If heat is now generated by the battery, this heat flows to the latent heat storage device. This causes the phase change materials to heat up. When the phase change temperature of the material with the lower phase change temperature is reached, it begins to change its state of aggregation, for example to melt. As long as this material has not completely changed its phase, its temperature does not increase any further. If heat is increasingly generated by the battery, this can be diverted to the latent heat storage device, which means that the temperature of the battery does not increase any further.

Phase change materials within the meaning of the invention can be those which can change their state of aggregation from solid to liquid, from liquid to gaseous or from solid to gaseous.

The phase change material can be surrounded at least in regions by a thermal insulation material, so that it is thermally insulated at least in regions.

The corresponding phase change temperature is preferably ≧10°C, preferably ≧20°C, preferably ≧50°C, preferably ≧100°C and/or ≦350°C, preferably ≦300°C, preferably ≦200°C.

The coupling with a latent heat storage device also ensures that the temperature of the battery does not drop below its operating temperature. If the heat generation by the battery decreases and the battery cools down, energy is withdrawn from the phase change materials, which in turn means that the phase change materials of the latent heat storage devices increasingly harden or condense, but the battery temperature does not drop any further until the thermal energy in the phase change materials is exhausted. This releases heat, which is conducted to the battery. Assuming that the battery and phase change materials are in thermal equilibrium, the battery is kept at the phase change temperature, e.g.

The passenger compartment of a vehicle can also be heated in a similar way. A phase change material is preferably selected here whose phase change temperature corresponds to the temperature to be set in the passenger compartment. The phase change material is brought into thermal contact with the passenger compartment. If the passenger compartment now heats up, for example due to solar radiation, heat is conducted to the phase change material, which as a result begins to change its phase, for example to melt. If, on the other hand, the passenger compartment temperature falls below the phase change temperature of the phase change material and this is not already completely in the cooler phase, heat is conducted from the phase change material into the passenger compartment, while the material increasingly changes its phase towards the colder phase, i.e. it hardens, for example. Thermal contact can be established using various heat conduction concepts, such as heat pipes. The phase change temperature is preferably selected in such a way that the temperature to be set assumes the desired value.

In addition to separate temperature control for the battery and passenger compartment, it is also possible to couple the temperature control systems with one another. For example, heat generated by the battery and stored in the phase change material can be dissipated to the passenger compartment to warm it. Of course, it is also possible for heat dissipated from the passenger compartment to be stored in the phase change material and then used to heat the battery.

In various situations it is conceivable that the passenger compartment and/or the battery of a vehicle should be heated without a sufficient amount of heat having already been generated in the passenger compartment or the battery to supply the latent heat storage device or its phase change material with the necessary heat to load. On the other hand, it can also happen that the phase change material is already completely in the warmer state of aggregation, so that further heat cannot be dissipated without increasing the temperature. In such cases is it is possible to preheat the latent heat store or the phase change material and the battery from the outside and thus bring the battery to the optimal operating temperature and at the same time store enough thermal energy in the phase change material or, if the battery temperature is too high, reduce the temperature slightly to optimize the service life if this is due to the heat generated during charging has heated up too much. This can happen, for example, during a charging process of the battery via an “on board” internally located in the vehicle or an external “off board” charger or electronic load during (energy consumption). Thus, during the charging of the battery, heat can be generated at the same time by a device supplied with voltage from the outside, with which heat the latent heat accumulator is put into a state of aggregation by absorbing heat. On the other hand, it is also possible to cool down a phase change material that is in the warmer state of aggregation during charging, so that it completely changes to its cooler state of aggregation. The passenger compartment and/or the battery can thus be tempered, heated or cooled to a predetermined temperature by the voltage provided by a charging device. In principle, the phase change materials themselves can also be viewed as latent heat storage devices.

Vehicles within the meaning of the invention are understood to mean, in particular, motor vehicles which have at least one battery. These are preferably vehicles which are propelled at least in part by electric motors. This includes purely electrically powered vehicles (EV) as well as hybrid vehicles such as plug-in hybrid vehicles (PHEV). Vehicles with internal combustion engines are also included, in which a battery is used, for example, to operate the starter.

All materials that have a phase change temperature in the desired temperature range can be used as phase change materials. The phase (state of aggregation) can change from liquid to gaseous, from solid to gaseous, or preferably from solid to liquid. For example, phase change materials with ionic liquids, salts that melt at room temperature, liquid crystals, organic solvents such as tert-butanol, glycerol, ethylene carbonate (EC) are possible. Solutions of salts in water or in solvents, including mixtures, are also suitable.

According to the present invention, a battery with an integrated latent heat store is also specified. One or more battery cells, such as flat battery cells or round cells, are in thermal contact with at least two phase change materials. Preferably, the phase change temperature of at least one of the phase change materials is at or near the optimum operating temperature of the battery.

Preferably, the battery is in thermal contact with at least two phase change materials that have different phase change temperatures. This makes it possible to absorb heat generated during normal battery operation with the phase change material that has the lower phase change temperature and, in the event that the battery causes an increase in the heat generated, which leads to heating to the phase change temperature of the second phase change material, this heat in addition to store in the second phase change material.

It is preferred if the phase change material or the phase change materials surround the battery cells at least in regions and are particularly preferably integrated directly into a battery housing of the battery. The battery cells are therefore embedded in the phase change materials and can touch them directly. It is particularly preferred here if the phase change material or materials are not electrically conductive, since no further measures for electrical insulation are then necessary. In this case, a particularly preferred phase change material is paraffin. This also has the advantage that it effectively dampens shocks and mechanical vibrations both in the solid and in the liquid state.

An embodiment in which a battery housing is filled with the phase change materials and one or more battery cells in the battery housing are embedded in the phase change materials is particularly preferred. In this way, a very direct transfer of heat between battery cells and latent heat storage is possible. A cooling device, such as a heat pipe for air recooling, can also be installed in the upper area of the battery.

The thermal coupling between phase change materials and the passenger compartment and/or battery can take place in various ways. On the one hand, a coupling via thermally conductive solids or liquids, i.e. thermal conductors, is possible.

Basically, the heat transport in solids works via vibrations of the lattice building blocks. The lattice building blocks move faster and are therefore more energetic. Through collisions with neighboring particles, they transfer their energy to other lattice building blocks. The other lattice building blocks begin to oscillate until the entire solid is heated. The heat always flows in the direction of the temperature gradient, which corresponds to z. B. can be the route from the latent memory to the colder passenger compartment of the vehicle. Metals are particularly good conductors of heat (e.g. aluminum, copper or alloys such as AlMgSi _0.5 ) and combine good heat conduction with low weight and low cost. With metals, the heat is transferred not only by the lattice vibrations but also by freely moving charge carriers, the electrons, which is why the thermal conductivity is particularly high.

The heat conductor can then preferably have or consist of aluminum, copper, manganese, silicon, at least one alloy of these materials and/or AlMgSi _0.5.

Another way of conducting heat is to provide a heat pipe system, in which case heat transport means with a low evaporation temperature are used.

Heat pipes basically contain a hermetically encapsulated volume, usually in the form of a tube. It is filled with a working medium (e.g. alcohol), which fills the volume to a small extent in a liquid state and to a large extent in a vapor state. It contains a heat transfer surface for the heat source and heat sink.

When heat is introduced from the passenger compartment, the working medium begins to evaporate. As a result, the pressure in the vapor space is increased locally above the liquid level, which leads to a low pressure drop within the heat pipe. The resulting vapor therefore flows in the direction of the condenser (e.g. cooler latent storage), where it condenses due to the lower temperature (heat sink). The previously absorbed heat is released back to the latent storage. The now liquid working medium returns to the evaporator by gravity (e.g. thermosyphon) or by capillary force (e.g. heat pipe). The advantage of using heat pipes is the extremely fast heat transport. In relation to the amount of heat and speed, this can be up to 100 to 1,000 times higher than with geometrically identical components made of solid aluminum or copper. According to the invention, heat pipes can be heat pipes and/or thermosiphons.

The invention makes it possible, among other things, to thermally charge the latent heat accumulator of a vehicle in the cold season in parallel with the electrical charging of the battery in order to have a heater in the vehicle.

The battery can also be kept in the favorable working temperature range and the waste heat from the battery can be fed into the heating of the passenger compartment.

As a result, the valuable electrical energy does not have to be used from the battery while driving.

Battery temperature control benefits battery life and battery performance.

The invention is to be explained in more detail below using a few examples.

• 1 einen beispielhaften Aufbau einer erfindungsgemäßen Batterie, die über einen Latentwärmespeicher temperierbar ist;
• 2 einen beispielhaften Aufbau einer erfindungsgemäßen Batterie mit einem Luft-Wärmetauscher zur Klimatisierung eines Fahrzeuginnenraumes; und
• 3 den schematischen Aufbau eines erfindungsgemäßen Fahrzeugs.

It shows

• 1 an exemplary structure of a battery according to the invention, which can be temperature-controlled via a latent heat storage device;
• 2 an exemplary structure of a battery according to the invention with an air heat exchanger for air conditioning a vehicle interior; and
• 3 the schematic structure of a vehicle according to the invention.

First, four situations are to be shown in which the method according to the invention and the devices according to the invention can be used.

In a first situation, the vehicle is stationary to charge the battery while the passenger compartment is being heated.

When charging the battery via the charger - it is z. B. a 12 V service connection of the charger, or the voltage required for the supply is set via the DC/DC converter integrated in the vehicle or the charger is set to the required charging voltage - the heat energy for the latent heat storage device, the drive battery, is supplied at the same time brought to the optimum temperature and the passenger compartment tempered to a preset temperature value (cooled or heated) by the user. The latent storage is very well insulated so that the heat is not permanently released into the environment and may be stored for longer periods (e.g. overnight).

When the battery charging process is complete, the charger has the additional task/function of reducing the temperature to the value preset by the user in the vehicle and the battery to the optimal operating temperature of e.g. 25°C. to keep.

A second situation is the heating of the passenger compartment while the electric vehicle is in operation.

In this operating mode, the latent storage or the phase change material releases the heat to the passenger compartment in a controlled manner via thermal coupling via solid-state transitions. The control via solid transitions can take place via different thicknesses of the contact surfaces between two transitions or via the cross sections of heat pipes.

The waste heat from the battery, which is generated during operation, is used to supply thermal energy to the latent storage, also via thermal coupling. During breaks (parking for shopping, working hours, etc.), when there is no connection via the charger, the phase change material stores the thermal energy particularly well through additional insulation and reduces the cooling of the battery through appropriate heat feedback. When heat is released to the solid body or to the environment, the agent used in the latent storage changes from a liquid to a solid state of aggregation.

A third example situation is that of the stationary vehicle being charged, with the passenger compartment being cooled.

During the charging process, the vehicle can be cooled either by a cooler assembly with compressor, condenser and evaporator, whereby the energy for cooling is supplied by the charger or the heat is dissipated from the passenger compartment via warmer tubes and/or heat pipes to the latent storage or to the evaporator from the passenger compartment will. The temperature gradient for rapid heat dissipation is created by a heat sink, e.g. B. by the heat difference to the latent storage or by operating a condenser fan at the end of the heat pipe.

As a fourth exemplary situation, that of the vehicle in operation will be described, the passenger compartment of which is being cooled.

On hot days and at temperatures that are above the comfort range, the latent storage can contribute to reducing the warming through its own heat capacity. In addition, a cooling effect can be achieved by transporting heat away from the passenger compartment via a built-in heat pipe system, with means with a low evaporation temperature being used to transport heat.

During breaks (parking for shopping, working hours, etc.) when there is no connection via the charger, the latent storage stores the thermal energy through optimal insulation of the storage, which provides cooling in the passenger compartment again when operation resumes.

The size (capacity) of the latent storage is optimized in such a way that the temperature in the passenger compartment can be regulated to a comfortable driving temperature (e.g. from 18 °C to 25 °C) for typical routes despite the low outside temperature.

1 shows an example of a battery in which a latent heat storage device is integrated. In this case, a first phase change material 2 and a second phase change material 3 emulsified or microencapsulated in this first phase change material are accommodated in a battery housing 1 . A multiplicity of battery cells 4 are embedded in the phase change materials 2 and 3 . Since the first latent heat storage material 2 has a high thermal capacity, the temperature of the battery remains in the optimum range, for example 25° C., for a long time. The second phase change material 3 can be formed, for example, by microencapsulated paraffins, which have a different phase change temperature than the first phase change material 2, for example 38°C. After the first phase change material 2 has melted, the temperature can be transported by convection from the heat source, for example the battery cells, to the recooler, which can transport heat to the passenger compartment, for example, and can thus be used for temperature conditioning of the passenger compartment.

The second phase change material 3 is provided for heat peaks at the battery, ie temporary heat surges. Due to the higher temperature occurring during a thermal surge, the second phase change material 3 is melted and cooling is thus achieved.

2 shows an exemplary structure of a battery according to the invention with an air heat exchanger 5 for air conditioning a vehicle interior. The air heat exchanger 5 is here arranged above the battery cells 4 and the latent heat storage device 2 . The air heat exchanger 5 is in thermal contact with the phase change materials 2 via a large number of heat pipes 7 . as well as in 1 , The battery cells 4 are embedded in the latent heat storage materials 2 and surrounded by them. as well as in 1 , here the latent heat storage material 2 can be a phase change heat storage medium in which two different phase change materials with different phase change temperatures are present, with one phase change material in the other is mixed in or encapsulated. A phase change material can also be present in a carrier medium.

A heating device 8 can also be provided underneath the battery cells 4, with which the phase change material 2 can be heated from the outside. In this way, the phase change material can be preheated, for example during a charging process of the battery. The battery cells 4 and the phase change material 2 surrounding them and the heating device 8 are accommodated within the battery housing, which is insulated from the environment by thermal insulation 6 . In this way, the battery does not heat up due to heat input from the outside and does not cool down due to heat dissipation to the outside.

Heat can be exchanged between the interior of the battery and, for example, the passenger compartment of a vehicle via the air heat exchanger 5, so that mutual temperature control is possible.

3 shows an example of a vehicle 11 according to the invention, which can be an electric vehicle 11, for example. The vehicle 11 has a battery 1, which can be designed, for example, as described above. The vehicle 11 also has a passenger compartment 9 . The temperature of the battery 1 and the passenger compartment 9 can be controlled by means of a temperature control device which has a latent heat store 10 with at least one phase change material 2 . Here, a heat exchange takes place between the phase change material 2 and the battery 1 via an element 12 for establishing a thermal contact. A heat exchange between the passenger compartment 9 and the phase change material 2 takes place via another
Element 13 for making a thermal contact. The elements for establishing a thermal contact 12 and 13 and the latent heat accumulator 10 with the at least one phase change material 2 form a temperature control device for the vehicle 11. The elements 12 and 13 can be, for example, heat conductors, heat pipes, thermosiphons and/or elements for convective heat transfer .

It is also possible for the battery 1 and/or the passenger compartment 9 to be tempered, heated or cooled to a predetermined temperature by a voltage provided by a charger 14 . The phase change material 2 can optionally also be heated or cooled directly via the charging device 14 .

Claims (11)

Vehicle (11) with at least one battery (1) and at least one passenger compartment (9) and with at least one temperature control device, wherein the temperature control device has at least one phase change material (2) which is connected to a passenger compartment (9) of the vehicle (11) and to a The battery (1) of the vehicle (11) is thermally coupled so that heat can be exchanged between them, characterized in that the temperature control device has at least two of the phase change materials, one of the phase change materials (3) being mixed into the other of the phase change materials (2) and /or is emulsified, and the phase change material (3) mixed or emulsified in the other phase change material (2) is microencapsulated by means of a plastic encapsulation to form capsules with a diameter of ≦30 μm and/or ≧2 μm. Vehicle (11) after claim 1 , characterized in that the temperature control device for producing the thermal contact has one or more elements (12, 13) selected from: at least one heat conductor, at least one thermosiphon, at least one heat pipe and/or at least one convective heat exchanger. Vehicle (11) according to one of the preceding claims, characterized in that a phase change temperature of at least one of the phase change materials (2, 3) corresponds to an operating temperature of the battery (1) or is essentially the same or corresponds to a passenger compartment temperature to be set or is essentially the same is equal to. Vehicle (11) according to one of the preceding claims, characterized in that at least two phase change materials (2, 3) with different phase change temperatures are provided, the phase change temperature of one of the phase change materials (2, 3) preferably being ≥ 0 °C and/or ≤ 200 °C C and the phase change temperature of the other phase change material (2, 3) is ≥ 50 °C and/or ≤ 400 °C. Method for tempering a passenger compartment and at least one battery of a vehicle according to one of the preceding claims, wherein the passenger compartment (9) is heated by heat from a phase change material (2) being conducted into the passenger compartment (9) and/or the passenger compartment (9) is cooled by conducting heat from the passenger compartment (9) into the phase change material (2), and the battery (1) is heated by conducting heat from the phase change material (2) to the battery (1). and/or the battery (1) is cooled by conducting heat from the battery (1) into the phase change material (2). Method according to the preceding claim, characterized in that heat is supplied to the phase change material (2) during a charging process of the battery (1), which heat is generated by a voltage source (14) connected externally to the vehicle. Battery of a vehicle with at least one battery cell (4) and with at least one latent heat store which has at least two phase change materials (2, 3) which are in thermal contact with the at least one battery cell (4), one of the phase change materials (3) in the other of the phase change materials (2) is mixed in and/or emulsified, with the phase change material (3) mixed or emulsified in the other phase change material (2) being microencapsulated, by means of a plastic encapsulation to form capsules with a diameter ≦30 μm and/or ≧2 μm. battery after claim 7 , characterized in that a phase change temperature of at least one of the phase change materials (2, 3) corresponds to an operating temperature of the battery (1) or is substantially the same. battery after claim 7 or 8th , characterized in that at least two phase change materials (2, 3) are provided with different phase change temperatures, the phase change temperature of one of the phase change materials (2, 3) preferably being ≥ 0 °C and/or ≤ 200 °C and the phase change temperature of the other phase change material ( 2, 3) ≥ 50 °C and/or ≤ 400 °C. battery after one of Claims 7 until 9 , characterized in that at least one of the phase change materials (2, 3) or the latent heat storage device at least partially surrounds and/or directly contacts the at least one battery cell (4). battery after one of Claims 7 until 10 , characterized in that the battery (1) has a cooling device (5) which is preferably arranged in an upper region of the battery and preferably has a heat pipe for air recooling.

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