Device for temperature control of a battery, vehicle, and method for heating and cooling a battery

Abstract

A system and method for heating or cooling a battery, including a controller and a temperature control loop, the temperature control loop including an auxiliary medium configured to exchange heat with a container having a latent heat storage medium and a vehicle traction battery, a pump configured to circulate the auxiliary medium, and a triggering device having a movable sealing element to selectively expose a nucleation surface to the latent heat storage medium to trigger a phase change process and exchange heat with the auxiliary medium.

Description

Technical Field

[0001] The present invention relates to a device for controlling the temperature of a battery, a vehicle having such a device, and a method for heating and cooling a battery. Background Art

[0002] In a vehicle, a storage battery is used as a rechargeable storage unit for electrical energy. In addition to serving as a starter battery, electric vehicles and hybrid vehicles also have a traction battery for the electric drive of the vehicle.

[0003] These storage batteries are generally temperature-sensitive and should operate within a narrow temperature range. At low temperatures, for example, when the temperature is below -25°C, the available capacity of the storage battery is limited. However, at higher temperatures, for example, above 45°C, it may be necessary to cool the battery because the battery itself generates heat during its operation and the battery may be damaged at too high a temperature.

[0004] As the temperature drops, the internal resistance of the storage battery increases. Due to the increased resistance, the voltage drop under load increases, and thus for the same load, the available capacity is lower. There is also a risk of freezing the electrolyte used in the storage battery.

[0005] This temperature dependence limits the availability of the storage battery in a motor vehicle at lower external temperatures and is thus particularly problematic for motor vehicles with partial or only electric operation. Raising the battery temperature by about 5°C to 10°C can significantly increase the available capacity.

[0006] To solve this problem, for example, electrical heating for the battery is known. In addition, DE 10 2011 002 549 A1 proposes battery temperature control by means of a material with a change in aggregation state. A device for controlling the temperature of a battery is described, which includes a battery and a latent heat storage that can change its aggregation state from liquid to solid and thus release crystallization heat to heat the battery, where crystallization can be triggered by a pulse. The latent heat storage is contained in a housing arranged around the battery.

[0007] The inventors have found that in the device described in DE 10 2011 002 549 A1, it is not possible for the latent heat storage to absorb heat independently of the battery, that is, the latent heat storage can only be returned to the liquid state by the heat released by the battery. Moreover, the complete phase change of the latent heat storage from solid to liquid is hindered because the circulation of the latent heat storage is not possible in the solid state. Moreover, the described device requires substantial structural changes related to the installation of the battery in a motor vehicle. Summary of the Invention

[0008] Therefore, the present invention is based on the possibility of eliminating the above-mentioned drawbacks. In particular, a device and a method for temperature control of a battery of a motor vehicle are proposed, by means of which the battery can be heated independently of an electric drive heat source. Moreover, it is desirable to be simply integrated into a conventional battery heating and cooling system.

[0009] The basic idea of the present invention is to store thermal energy in a latent heat storage medium, send the stored thermal energy to an auxiliary medium when needed (for example, at very low temperatures), and use the heated auxiliary medium to heat the battery. However, at high temperatures, the thermal energy can be transferred from the battery to the auxiliary medium, and from the auxiliary medium to the latent heat storage medium and stored therein. In other words, the heat transfer between the latent heat storage medium and the battery is carried out indirectly through the auxiliary medium, which always exists in a liquid phase, and can therefore be circulated by a pump, for example.

[0010] This allows the latent heat storage medium to be arranged in a separate container separate from the battery. There is no need to transport or circulate the latent heat storage medium.

[0011] An embodiment according to the present invention allows temperature control (in particular heating) of the battery independently of an external power source and thus, for example, when the vehicle is not connected to a charging station.

[0012] The embodiment can be advantageously integrated into a conventional battery heating and cooling system, such that at normal temperature, the auxiliary medium and thus the battery can also be cooled or heated, for example, by an air conditioning system or a PTC (positive temperature coefficient) heating element.

[0013] A device for temperature control of a battery according to one or more embodiments comprises a temperature control circuit having a pump device, a battery arranged in the temperature control circuit, a container arranged in the temperature control circuit and comprising a latent heat storage medium, and an auxiliary medium present in the temperature control circuit for indirect heat transfer between the latent heat storage medium and the battery.

[0014] The temperature control device can be used to heat the battery, cool the battery or both to heat and cool the battery, that is, the term "temperature control" refers to heating and / or cooling.

[0015] The term "battery" includes both single or multiple main batteries and single or multiple secondary batteries (accumulators). Examples of batteries in the sense of the present application are lithium-ion accumulators, such as lithium polymer accumulators, lithium cobalt dioxide accumulators, lithium titanate accumulators, lithium-air accumulators, lithium manganese dioxide accumulators, lithium iron phosphate accumulators, and tin-sulfur lithium-ion accumulators. The battery can be configured, for example, as a starter battery or a traction battery of a vehicle.

[0016] The latent heat storage medium is a phase change material (PCM), and due to its normal specific heat capacity, its potential heat of fusion, dissolution or absorption is greater than the heat it can store. Thus, like the specific heat capacity, the latent heat of a phase change (e.g., from liquid to solid) can be used to store thermal energy.

[0017] The latent heat storage medium can be used so that its phase change from liquid to solid can be utilized, and vice versa (i.e., solidification and melting). The phase change temperature of the solid-liquid phase change can be in the temperature range between 10°C and 90°C in some embodiments, between 30°C and 80°C in some embodiments, and between 40°C and 60°C in some embodiments.

[0018] Suitable latent heat storage media can be, for example, hydrated salts, mixtures of hydrated salts or mixtures of paraffins. In one embodiment, sodium acetate trihydrate is used as the latent heat storage medium, which has a phase change temperature of 58°C for the solid-liquid phase change, but can also exist in a metastable state as a supercooled melt at lower temperatures down to -20°C. Because the salt is dissolved in its crystal water. If crystallization is triggered, the latent heat storage medium is heated again to the phase change temperature of the solid-liquid phase change and releases thermal energy.

[0019] The heat of fusion associated with the solid-liquid phase change is approximately 270 kJ / kg, and is thus greater than most other latent heat storage media having a solid-liquid phase change temperature in the low temperature range between 40°C and 100°C. In other words, for sodium acetate trihydrate, the energy that can be stored per kg is particularly high, so that little latent heat storage medium is required to store a specific amount of thermal energy, and thus a correspondingly smaller container 5 can be selected. In this way, for example, installation space can be saved in a vehicle equipped with the device according to the invention.

[0020] Other examples of latent heat storage media are sodium sulfate decahydrate (solid-liquid phase change temperature 32.5°C), dipotassium hydrogen phosphate hexahydrate (solid-liquid phase change temperature 14°C) and calcium nitrate tetrahydrate (solid-liquid phase change temperature 43°C).

[0021] The latent heat storage medium can be arranged in a closed container, where the container is not limited to a specific form. The volume of the container can be greater than the volume of the latent heat storage medium to allow for any thermal expansion of the latent heat storage medium. Thus, it can be ensured that the latent heat storage medium will not be released (e.g., due to leakage).

[0022] The container can be made of a material with high thermal conductivity to allow for good heat transfer between the latent heat storage medium present in the container and the auxiliary medium.

[0023] An auxiliary medium is present in the temperature control circuit and is used for indirect heat transfer between the latent heat storage medium and the battery. First, for example, at very low battery temperatures, the auxiliary medium can absorb thermal energy from the latent heat storage medium (e.g., by means of the thermal conductivity of the container). Then, the heated auxiliary medium is made to flow by means of a pump device so that it reaches the battery and can release thermal energy to the battery. For this purpose, the battery can be arranged in a thermally conductive housing.

[0024] Secondly, the auxiliary medium can also absorb thermal energy from the battery and transfer it to the latent heat storage medium.

[0025] The auxiliary medium can, for example, contain water or consist of water.

[0026] Due to the use of the auxiliary medium, it is not necessary to transport the latent heat storage medium between different chambers. Thus, the risk of an undesired release of the latent heat storage medium can be reduced.

[0027] The temperature control circuit can be formed by lines (e.g., pipes or hoses) in which the auxiliary medium is present and can be made to flow by means of a pump device. The arrangement of the components (e.g., the battery or the container) in the temperature control circuit means that heat transfer can take place between the respective components and the auxiliary medium (e.g., due to direct contact of the lines with the components). To improve heat transfer, the temperature control circuit can contain devices for improving heat transfer (e.g., ribbed or meandering structures) to increase the surface area.

[0028] According to various embodiment variants, the latent heat storage medium can exist in a metastable state below its phase change temperature (i.e., below the solid-liquid phase change temperature).

[0029] Thus, a latent heat storage medium can be used which can exist in a metastable state as a supercooled melt or a supercooled solution. Then, the phase change from liquid to solid with the release of thermal energy can be triggered by nucleation in the supercooled melt or solution (e.g., by means of a pulse or seeding). Advantageously, the phase change time and thus the start of heat release can be controlled in this way.

[0030] For example, the latent heat storage medium can be cooled to ambient temperature without crystallization because the latent heat storage temperature is in its metastable state at ambient temperature.

[0031] The metastable state exists down to a lower temperature limit of 0 °C, or in some embodiments down to a lower temperature limit of -10 °C, or down to a lower temperature limit of -20 °C, or even down to a lower temperature limit of -30 °C. Thus, heat release is possible until the said lower temperature limit is reached.

[0032] According to a further embodiment variant, the device may comprise heating and / or cooling equipment for temperature control of an auxiliary medium in a temperature control circuit. The heating and / or cooling equipment may be configured, for example, as an air conditioning system or a PTC heating element. It may be electric.

[0033] In this way, when electrically heated, thermal energy can be supplied to the auxiliary medium. This electrical heating can be achieved, for example, by an external power source, for example if the traction battery of a hybrid vehicle is being charged at a charging station, electrical energy can be supplied from the outside.

[0034] The heated auxiliary medium can then transfer the thermal energy to the latent heat storage medium, such that it can undergo a phase change associated with heat absorption. Thus, the latent heat storage medium can be "regenerated" later as needed in order to be able to release thermal energy to the auxiliary medium again to heat the battery.

[0035] According to various embodiment variants, the temperature control circuit may comprise a bypass for bypassing the battery, and a shut-off device for enabling and disabling the bypass.

[0036] When the bypass is deactivated, the auxiliary medium can flow to the battery, and thermal energy can be transferred between the battery and the auxiliary medium. When the bypass is activated, the auxiliary medium can flow through the bypass, bypassing the battery, and no thermal energy is transferred between the battery and the auxiliary medium. The shut-off device is thus used to close and open the bypass such that the auxiliary medium flows through the bypass or through the part of the temperature control circuit in which the battery is arranged.

[0037] For example, the bypass can be activated during heating of the auxiliary medium and thus of the latent heat storage medium by the heating and / or cooling equipment. Thus, simultaneous heating of the battery can be eliminated. This is particularly advantageous if a high temperature is reached, for example a temperature above 60 °C or 70 °C which could cause battery damage. However, the bypass is deactivated for temperature control of the battery.

[0038] According to a further embodiment variant, the device may comprise a starting device arranged in a container and configured to trigger the crystallization process of the latent heat storage medium.

[0039] The starting device can, for example, release or provide crystal nuclei, or trigger a pulse that causes the latent heat storage medium to crystallize. With the aid of the starting device, the crystallization time can advantageously be controlled such that the heat release associated with the liquid-solid phase change can occur at a specific time (for example, when the battery needs to be heated).

[0040] The starting device can, for example, comprise a nucleation surface and a sealing element. The nucleation surface is configured to trigger the crystallization process of the latent heat storage medium when the temperature and pressure conditions permit (i.e. for example when the latent heat storage medium is present as a supercooled melt or supercooled solution). For this purpose, the nucleation surface can, for example, comprise crystal nuclei (for example in the form of seeds).

[0041] The sealing element is configured to intermittently seal the nucleation surface from the latent heat storage medium. In other words, by means of the sealing element, the contact between the nucleation surface and the latent heat storage medium can be controlled. If the nucleation surface is sealed from the latent heat storage medium, i.e., there is no contact, crystallization of the latent heat storage medium can be suppressed. When the seal is released, the crystallization process is triggered.

[0042] The sealing element can be, for example, part of an electromagnetic actuator valve, such as a solenoid valve that can be configured for direct control. The sealing element can be connected to a magnetic holding element (such as a rod), which is moved between a sealed position and an unsealed position by an electromagnetic actuator (such as a coil).

[0043] According to a further embodiment variant, the device can comprise a control unit, which is designed and configured to control the pump device and / or the shut-off device and / or the starting device and / or the heating and / or the cooling device (e.g., according to the battery temperature).

[0044] To determine the battery temperature, the device can comprise a battery temperature sensor, and the sensor signal from the battery temperature sensor is transmitted to and processed by the control unit. Alternatively, the battery temperature can be estimated, for example, based on the ambient temperature, or if the battery is located in an open vehicle, based on the external temperature.

[0045] For example, if the battery temperature is below a lower limit value, the pump device and the applicable shut-off device and / or starting device can be controlled such that the thermal energy from the latent heat storage medium is transferred to the auxiliary medium and from the auxiliary medium to the battery, and the battery is heated.

[0046] However, if the battery temperature reaches or is above the lower limit value or exceeds an upper limit value, the pump device, the heating and / or cooling device, and the applicable shut-off device and / or starting device can be controlled such that the auxiliary medium is heated by the heating and / or cooling device, and the thermal energy is transferred from the auxiliary medium to the latent heat storage medium.

[0047] Optionally, the device can comprise a status sensor for determining the phase state of the latent heat storage medium. The status sensor can be configured, for example, as a temperature sensor. By means of the status sensor, the phase state of the latent heat storage medium (e.g., solid or liquid) can be established. The corresponding sensor signal can also be transmitted to and evaluated by the control unit, and for controlling the pump device and / or the shut-off device and / or the starting device and / or the heating and / or the cooling device.

[0048] For example, it can be provided that measures for heating the battery are only taken when the latent heat storage medium is in the liquid phase state, because otherwise the phase change associated with the heat release from the liquid to the solid does not occur.

[0049] However, if the latent heat storage medium is heated, heating of the auxiliary medium by means of the heating and / or cooling device can be ended when the liquid phase state is reached or when the temperature limit value of the latent heat storage medium is exceeded, since further heating does not bring any decisive advantage and further thermal energy cannot be stored permanently.

[0050] When using sodium acetate trihydrate as the latent heat storage medium, a temperature of 60 °C can be created as the temperature limit value. Since the solid-liquid phase transition temperature of sodium acetate trihydrate is 58 °C, it can be assumed that it exists completely in the liquid phase state at a temperature of 60 °C.

[0051] Furthermore, the device can include a device for determining the operating state of the battery, that is, a device that can determine whether there is a power demand for the battery or whether there will soon be a power demand.

[0052] The corresponding signals from the device can also be transmitted to the control unit and evaluated, as well as for controlling the pump device and / or the shut-off device and / or the start-up device and / or the heating and / or cooling device.

[0053] For example, it can be provided that measures for heating the battery are only taken when there is a power demand for the battery or when there will soon be a power demand. Therefore, it is only advantageous to heat the battery when it is actually necessary.

[0054] If the battery is a vehicle battery, the device for determining the operating state of the battery can be a start command device for starting the vehicle (for example, a start button). In this case, if the vehicle is to be started, there is a power demand for the battery.

[0055] For example, if the vehicle's door handle is activated, it can be expected that there will be a power demand for the battery in a short time. If the vehicle door is opened, it is very likely that the vehicle will be started, so it can be assumed that there is a power demand for the battery.

[0056] A motor vehicle according to the invention includes a device having the above-mentioned features. The vehicle can be configured as an electric or hybrid vehicle (for example, configured as a mild hybrid vehicle or a full hybrid vehicle). The battery can be, for example, a traction battery of an electric vehicle or a hybrid vehicle.

[0057] It has been proven that one or more embodiments according to the invention are particularly advantageous for electric vehicles, because in these vehicles, there is no waste heat from an internal combustion engine that can be used to heat the battery, and these vehicles rely on the normal operation of the battery because they have no alternative energy supply source.

[0058] A method for heating a battery of the above - mentioned device according to one or more embodiments includes causing a phase change related to heat release of a latent heat storage medium, heating an auxiliary medium by the released heat, generating a flow of the heated auxiliary medium in a temperature control loop, and transferring thermal energy from the heated auxiliary medium to the battery.

[0059] The features of the method can be performed in the recited order, but can also be performed in a different order or in parallel with each other. For example, heating the auxiliary medium, generating the flow, and transferring the thermal energy generally occur mainly simultaneously.

[0060] The method according to one or more embodiments is performed by means of one or more devices as described above (for example, in a vehicle according to the invention). In this case, the statements explaining the devices above are also used to describe the method.

[0061] The phase change can be caused, for example, by the above - mentioned activation device. The phase change related to heat release is in particular a solid - liquid phase change.

[0062] According to various embodiment variants, the method can further include creating a lower limit value of the battery temperature and determining the battery temperature, where other method steps can be performed only if the temperature drops below the lower limit value. The battery temperature can be determined or estimated directly, for example.

[0063] This embodiment of the method ensures that the battery is heated only when needed (i.e., at low temperatures).

[0064] According to another embodiment variant, the method can include causing a phase change related to heat absorption of the latent heat storage medium by supplying thermal energy to the latent heat storage medium.

[0065] For this purpose, for example, the auxiliary medium can be heated and the thermal energy can be transferred from the auxiliary medium to the latent heat storage medium. This method step can be performed before or after causing the phase change related to heat release of the latent heat storage medium, depending on the phase state of the latent heat storage medium at the start of the method.

[0066] A method for cooling a battery of the above - mentioned device according to one or more embodiments includes transferring thermal energy from the battery to an auxiliary medium, generating a flow of the heated auxiliary medium in a temperature control loop, and transferring thermal energy from the auxiliary medium to the latent heat storage medium.

[0067] The features of the method can be performed in the recited order, but can also be performed in a different order or in parallel with each other.

[0068] The method according to one or more embodiments is performed by means of a device according to the embodiments described above (i.e., in a vehicle according to the invention). In this case, the statements explaining the devices of different embodiments above are also used to describe the method according to one or more embodiments.

[0069] According to various exemplary variations, transferring thermal energy from an auxiliary medium to a latent heat storage medium causes a phase change related to heat absorption (e.g., from solid state to liquid state) of the latent heat storage medium. Thus, like the specific heat capacity, the energy related to the phase change can be stored in the latent heat storage medium. Therefore, more thermal energy can be provided for subsequently heating the battery.

[0070] The phase change of the method is a solid-liquid phase change. Two methods (i.e., the method for heating the battery and the method for cooling the battery) can be carried out alternately, for example, such that the latent heat storage medium serves as a temporary energy storage device. For example, at a lower external temperature, when starting a vehicle, it may be necessary to heat the battery arranged therein. This can be achieved using the method for heating the battery. After a specific operating cycle, the battery itself generates waste heat, which can now be used alone or in combination with the thermal energy provided by the heating and / or cooling device to heat the latent heat storage medium.

[0071] The claimed subject matter will now be described in more detail with reference to one or more embodiments. The one or more embodiments for illustration purposes include at least one specific embodiment that can implement the claimed subject matter. It should be understood that other embodiments can be used and structural or logical changes can be made without departing from the scope of protection defined by the claims. The drawings illustrate: BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Figure 1 is a schematic diagram of a device according to one embodiment;

[0073] Figure 2 is a schematic diagram of a device according to an embodiment during the regeneration of the latent heat storage medium;

[0074] Figure 3 is a schematic diagram of the device during the heating of the battery; and

[0075] Figure 4A 、 4B is a schematic diagram of a starting device in an embodiment in an enabled and disabled state. DETAILED DESCRIPTION

[0076] As required, detailed embodiments are disclosed herein; however, it should be understood that the disclosed embodiments are merely representative and can be implemented in various and alternative forms. These drawings are not necessarily to scale; some features may be exaggerated or minimized to show details of specific components. Thus, the specific structural and functional details disclosed herein are not necessarily restrictive, but merely provide a representative basis for teaching those skilled in the art to use the claimed subject matter in various ways.

[0077] Figure 1Fig. 0 shows a device 1 according to an embodiment. The device 1 has a temperature control circuit 3 including an auxiliary medium 7 (implemented by water in this embodiment), and the auxiliary medium 7 can be set to flow 15 by means of a pump device 4.

[0078] The device 1 further has a battery 2 arranged in the temperature control circuit 3. The battery 2 is a 400V traction battery of an electric vehicle in this embodiment. However, this and other embodiments can be used for temperature control of all fixed or mobile batteries regardless of their chemical composition.

[0079] In addition, the device 1 has a container 5 including a latent heat storage medium 6. In this embodiment, sodium acetate trihydrate is used as the latent heat storage medium 6, which has a solid-liquid phase change temperature of 50°C but can remain in a metastable liquid state at temperatures below -20°C.

[0080] The container 5 with the latent heat storage medium 6 is also arranged in the temperature control circuit 3 so that heat can be transferred between the latent heat storage medium 6 and the auxiliary medium 7.

[0081] Similarly, heat can be transferred between the auxiliary medium 7 and the battery 2. In other words, the auxiliary medium 7 is used for indirect heat transfer between the latent heat storage medium 6 and the battery 2. To improve the heat transfer between the auxiliary medium 7 and the battery 2, the temperature control circuit 3 is formed in a zigzag shape in the region of the battery 2.

[0082] The temperature control circuit 3 further includes heating and cooling equipment 8, and the auxiliary medium can be heated or cooled as needed by using the heating and cooling equipment 8.

[0083] In addition, the temperature control circuit 3 has a bypass 9 for bypassing the battery 2. By means of a shut-off device 10, the bypass can be enabled so that the auxiliary medium 7 flows through the bypass 9 but does not flow through the part of the temperature control circuit 3 including the battery 2 (see the flow 15 in Figure 2 ). However, when the bypass 9 is deactivated, the auxiliary medium flows through the battery part of the temperature control circuit 3 but does not flow through the bypass 9 (see the flow 15 in Figure 3 ).

[0084] The container 5 includes a starting device 11 configured to trigger the crystallization process of the latent heat storage medium 6. As shown in Fig. 4, the starting device 11 has a nucleation surface 12 and a sealing element 13. In the embodiment shown in Fig. 4, the sealing element is connected to a magnetic rod 18, and the magnetic rod 18 can be moved between a deactivated state ( Figure 4A ) and an activated state ( Figure 4B ) by an electromagnetic actuator 17, and the electromagnetic actuator 17 is implemented by a coil through which an electric current flows in this embodiment.

[0085] In the deactivated state, the sealing element 13 seals the nucleation surface 12 against the latent heat storage medium 6, such that crystallization of the latent heat storage medium 6 can be prevented. However, if the latent heat storage medium 6, which is present in a metastable liquid state below the solid-liquid phase transition temperature, comes into contact with the nucleation surface 12 (i.e., the activation device 11 is in the activated state), where the nucleation surface 12 is not sealed against the latent heat storage medium 6 by the sealing element 13, crystallization of the latent heat storage medium 6 may be induced. The crystallization spreads very rapidly through the entire latent heat storage medium 6. Since crystallization is an exothermic process, thermal energy is released through the container 5 into the auxiliary medium 7.

[0086] The container 5 further includes a temperature sensor 16 for determining the temperature of the latent heat storage medium 6. Optionally, there may be additional temperature sensors (not shown) for determining the battery temperature.

[0087] As described below with reference to Figure 2 and 3 , the device 1 further includes a control unit 14 designed and configured to control, for example, the pump device 4, the shut-off device 10, the activation device 11, and the heating and cooling device 8 based on the battery temperature.

[0088] Reference Figure 2 , the charging or regeneration of the latent heat storage medium 6, i.e., the transition from the solid state to the liquid state, is first described below.

[0089] The regeneration process can be initiated, for example, by a command from the vehicle driver or automatically by the vehicle's control system, for example, if the latent heat storage medium 6 is present in a crystalline state and the external temperature is below a specific value (e.g., below 0 °C), and thus there is concern about the limited functionality of the battery 2. Further preconditions may be that the battery temperature exceeds a predefined limit value at the current time. These preconditions ensure that the regeneration process only occurs when it is likely that the battery 2 will need to be heated later, for example, due to the lower external temperature when the vehicle is parked, the battery temperature is expected to drop to a temperature at which the performance of the battery 2 is limited. However, at a higher external temperature, there is no need to heat the battery 2, and thus the energy required for regeneration can be saved.

[0090] To regenerate the latent heat storage medium 6, its temperature is raised at least to the solid-liquid phase transition temperature. This is achieved by heating the auxiliary medium 7 by means of the heating and cooling device 8. In an exemplary embodiment using sodium acetate trihydrate as the latent heat storage medium 6, the temperature of the auxiliary medium 7 can be increased, for example, to at least 70 °C. The heating and cooling device 8 is controlled accordingly by the control unit 14.

[0091] Furthermore, the pump device 4 is enabled by the control unit 14 to generate a flow 15 of the auxiliary medium 7. In addition, a corresponding control signal is output by the control unit 17 to configure the shut-off device 10 such that the bypass 9 is enabled. This prevents the heated auxiliary medium 7 from heating the battery 2.

[0092] Due to the heat transfer from the auxiliary medium 7 to the latent heat storage medium 6 (i.e., the supply of thermal energy), the latent heat storage medium 6 changes from the solid phase state to the liquid phase state. When the temperature of the latent heat storage medium 6 reaches a specific limit value, which reaches, for example, 60 °C in the case of sodium acetate trihydrate, the heating of the auxiliary medium 7 is terminated because the corresponding control signal is emitted by the control unit 17 to the heating and cooling device 8. Since the temperature of the latent heat storage medium 6 does not change during the phase change, it is usually sufficient that the limit value is just above the solid-liquid phase change temperature. If the temperature further increases, it is assumed that the complete phase change has occurred, i.e., the latent heat storage medium 6 now exists entirely in the liquid phase state.

[0093] After the regeneration process is completed, the latent heat storage medium 6 remains in the liquid state even at a temperature below the solid-liquid phase transition temperature, and as long as no nucleation of the crystallization process occurs, the latent heat storage medium 6 is metastable. For example, even when the vehicle is parked overnight at a low temperature, the latent heat storage medium can remain in the liquid state.

[0094] Now referring Figure 3 to, the execution of a representative method according to one embodiment for heating the battery 2 is described.

[0095] The heating of the battery 2 can depend on various preconditions. For example, it can be provided that the battery 2 is heated only when the vehicle driver starts the vehicle by activating the start button and the battery temperature is below a lower limit value of, for example, -25 °C. In addition, the latent heat storage medium 6 must be in the liquid phase state.

[0096] If the preconditions are met, the control unit 14 operates the activation device 11 such that the crystallization of the latent heat storage medium 6 is triggered ( Figure 4B ). For this purpose, the control of the sealing element is such that it does not seal the nucleation surface 12 against the latent heat storage medium 6. The contact of the latent heat storage medium 6 existing in the metastable state with the nucleation surface 12 triggers the crystallization associated with heat release. In other words, the phase change associated with heat release of the latent heat storage medium 6 is caused.

[0097] The released thermal energy is transferred to the auxiliary medium 7 and heats it. The pump device 4 is enabled by the control unit 14 to generate a flow 15 of the auxiliary medium 7. In addition, the control unit 17 issues a corresponding control signal, and the control signal is configured to close the device 10 such that the bypass 9 is deactivated. This prevents the heated auxiliary medium 7 from flowing only through the bypass 9.

[0098] Rather, the heated auxiliary medium 7 now flows through the part of the temperature control circuit 3 in which the battery 2 is arranged, such that the thermal energy is transferred from the heated auxiliary medium to the battery 2 and the battery 2 is heated.

[0099] The accompanying drawings are not necessarily to scale as to details and may be depicted as enlarged or reduced to provide a better overview. Accordingly, the functional details disclosed herein should not be construed as limiting, but merely as an illustrative basis that provides those skilled in the art with a basis for using the invention in various ways. In the drawings, like or similar elements are provided with like reference numerals where appropriate.

[0100] The expression “and / or” as used herein in a series of two or more elements refers to each of the listed elements being used alone or any combination of two or more of the listed elements being used. For example, if a described composition includes components A, B, and / or C, the composition may include A alone, B alone, C alone, a combination of A and B, a combination of A and C, a combination of B and C, or a combination of A, B, and C.

[0101] Although representative embodiments have been described above, it does not mean that these embodiments describe all possible forms of the claimed subject matter. The words used in the specification are descriptive words rather than restrictive words, and it should be understood that various changes can be made without departing from the spirit and scope of the claimed subject matter. Additionally, the features of various embodiments can be combined to form other embodiments that may not be explicitly described or shown.

Claims

1. A system for controlling the temperature of a battery, comprising: A controller; A battery configured to transfer heat to an auxiliary medium of a temperature control loop and transfer heat of the auxiliary medium from the temperature control loop; A container in the temperature control loop, the container containing a latent heat storage medium; and An activation device having a nucleation surface and a sealing element connected to a magnetic rod, the magnetic rod being movable between a deactivated state and an activated state by an electromagnetic actuator. In the deactivated state, the sealing element seals the nucleation surface relative to the latent heat storage medium. In the activated state, the sealing element exposes the nucleation surface to the latent heat storage medium to trigger a crystallization process and heat the auxiliary medium; Wherein, The controller is configured to control the activation device to heat the battery in response to the temperature of the battery being lower than a lower limit value; Wherein the temperature control loop includes a bypass configured to selectively bypass the battery. When the bypass is deactivated, the auxiliary medium flows to the battery and heat is transferred between the battery and the auxiliary medium. When the bypass is activated, the auxiliary medium flows through the bypass, bypassing the battery, and heat is not transferred between the battery and the auxiliary medium.

2. The system according to claim 1, further comprising a pump configured to circulate the auxiliary medium through the temperature control loop.

3. The system according to claim 1, wherein the latent heat storage medium can exist in a metastable state at a temperature lower than a relevant phase change temperature.

4. The system according to claim 1, further comprising heating and / or cooling equipment provided in the temperature control loop to heat and / or cool the auxiliary medium in response to a relevant request from the controller.

5. The system according to claim 1, wherein the system further comprises a valve connected to the controller for selectively enabling and disabling the bypass.

6. The system according to claim 1, wherein the activation device includes a lift valve.

7. The system according to claim 1, further comprising a temperature sensor communicable with the controller and configured to measure the temperature of the latent heat storage medium.

8. The system according to claim 1, wherein the latent heat storage medium includes sodium acetate trihydrate.

9. The system according to claim 1, wherein the battery includes a vehicle traction battery.

10. A method of heating a battery using the system according to any one of claims 1-9, comprising: Controlling, by a controller in response to the temperature of the battery being lower than a lower limit value, an activation device to expose a nucleation surface to cause a phase change of a latent heat storage medium to heat an auxiliary medium circulating through a temperature control loop including the battery; Activating a bypass of the temperature control loop to regenerate the latent heat storage medium in response to the latent heat storage medium existing in a crystalline state and an external temperature being lower than a specific value.

11. The method according to claim 10, wherein the activation device includes a solenoid valve.

12. The method according to claim 10, further comprising controlling a pump by the controller to circulate the auxiliary medium through the temperature control circuit.

13. The method according to claim 10, wherein the control is performed by the controller in response to the ambient temperature.

14. The method according to claim 10, further comprising controlling a heating and / or cooling device by the controller to selectively heat and / or cool the auxiliary medium to transform the latent heat storage medium into a solid phase.

15. The method according to claim 10, wherein the phase change comprises a solid-liquid phase change.

16. A system for temperature control of a vehicle traction battery, comprising: a controller; a temperature control circuit including an auxiliary medium configured to exchange heat with a container having a latent heat storage medium and the vehicle traction battery; a pump configured to circulate the auxiliary medium; and an activation device having a nucleation surface and a sealing element connected to a magnetic rod, the magnetic rod being movable between a deactivated state and an activated state by an electromagnetic actuator, in the deactivated state, the sealing element seals the nucleation surface relative to the latent heat storage medium, in the activated state, the sealing element exposes the nucleation surface to the latent heat storage medium to trigger a phase change process and heat exchange with the auxiliary medium, wherein, the controller is configured to control the activation device to heat the vehicle traction battery in response to the temperature of the vehicle traction battery being lower than a lower limit value, wherein the temperature control circuit includes a bypass configured to selectively bypass the vehicle traction battery, when the bypass is deactivated, the auxiliary medium flows to the vehicle traction battery, and heat is transferred between the vehicle traction battery and the auxiliary medium, when the bypass is activated, the auxiliary medium flows through the bypass, bypassing the vehicle traction battery, and heat is not transferred between the vehicle traction battery and the auxiliary medium.

17. The system according to claim 16, wherein the latent heat storage medium comprises sodium acetate trihydrate.

18. The system according to claim 16, further comprising a heating / cooling device configured to selectively heat / cool the auxiliary medium.

19. The system according to claim 18, further comprising a temperature sensor configured to measure the temperature of the latent heat storage medium.

20. The system according to claim 16, wherein the container is disposed away from the vehicle traction battery.

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