Charging device and method for charging a traction battery of an electrically powered motor vehicle

Abstract

Charging device for charging a traction battery (120) of an electrically powered motor vehicle (100), with a device for making an electrical connection to the traction battery (120), with a first storage unit (30) for storing thermal energy, wherein the first storage unit (30) comprises a reservoir (32) filled with a first coolant, which is water and / or glycol and has a temperature between 30°C and 50°C, with a second storage unit (40) for storing thermal energy, wherein the second storage (40) is a fuel tank of a filling station is formed and comprises a reservoir (42) filled with a second coolant, which is a fossil fuel and has a temperature between 30°C and 50°C and is lower than the temperature of the first coolant, with an energy transmission device (50) having a coolant line (52), wherein the energy transfer device (50) for transferring thermal energy between the first storage unit (30) and the traction battery (120) is thermally coupled to the first storage unit (30) and thermally coupleable to the traction battery (120), and wherein the energy transfer device (50) is furthermore thermally coupled to the second storage device (40) and thermally coupleable to the traction battery (120) for the transfer of thermal energy between the second storage device (40) and the traction battery (120), wherein the coolant line (52) is designed for selective supply of either the first coolant or the second coolant to the energy transmission device (50) and comprises at least one valve (56) which is connected on the one hand by fluid communication to the reservoir (32) of the first storage unit (30) and the reservoir (42) of the second storage unit (40) and on the other hand by fluid communication to a heat exchanger (110) of the motor vehicle (100), with a temperature control device (60) for temperature control of the first storage unit (30) and for temperature control of the second storage unit (40), wherein the temperature control device (60) comprises a heating device (62) which is thermally coupled exclusively to the first storage unit (30) to heat the first coolant, wherein the temperature control device (60) further comprises a refrigeration machine (64) which is thermally coupled to the first storage unit (30) and to the second storage unit (40), which represent two different thermal inertias, and which is designed and arranged to extract thermal energy from the second storage unit (40) and supply it to the first storage unit (30).

Description

[0001] The invention relates to a charging device for charging a traction battery of an electrically powered motor vehicle and a method for charging the traction battery of the electrically powered motor vehicle.

[0002] A charging device is known from DE 10 2017 113 845 A1. The charging device is equipped with a device for establishing an electrical connection to the traction battery, a storage unit for storing thermal energy, and an energy transfer device that is thermally coupled to the storage unit and thermally connectable to the traction battery for transferring thermal energy between the storage unit and the traction battery. The storage unit comprises a reservoir filled with a coolant. The traction battery can be cooled by means of the energy transfer device.

[0003] From WO 2012 / 045 678 A2, a method for increasing energy efficiency during the charging of electric vehicle batteries is known using a charging device. Waste heat generated by the charging device during the charging process is supplied to the electric vehicle to heat the batteries.

[0004] US 2017 / 0096073A1 discloses a charging device for charging a traction battery of an electric motor vehicle, comprising a first storage device for storing thermal energy and a second storage device for storing thermal energy, wherein the first storage device has a reservoir filled with a first coolant and the second storage device has a reservoir filled with a second coolant. The reservoir of the first storage device is a hot reservoir and the reservoir of the second storage device is a cold reservoir.The charging device further comprises an energy transfer device which is thermally coupled to the first storage unit and thermally coupleable to the traction battery for the transfer of thermal energy between the first storage unit and the traction battery, and which is furthermore thermally coupled to the second storage unit and thermally coupleable to the traction battery for the transfer of thermal energy between the second storage unit and the traction battery.

[0005] WO 2019 / 162 680 A1 and DE 10 2016 222 358 A1 reveal further state of the art.

[0006] The object of the present invention is to increase the energy efficiency of a charging process of the traction battery, particularly when a relatively low ambient temperature prevails.

[0007] The problem is solved by a charging device according to claim 1 and a method according to claim 2.

[0008] The charging device according to the invention is provided with a device for establishing an electrical connection to the traction battery, a first storage device for storing thermal energy, a second storage device for storing thermal energy, and an energy transfer device that is thermally coupled to the first storage device and the second storage device, and thermally coupleable to the traction battery, for the transfer of thermal energy between the first storage device, the second storage device, and the traction battery. The first storage device comprises a reservoir filled with a first coolant, which is water and / or glycol. The second storage device comprises a reservoir filled with a second coolant, which is a fossil fuel. The temperature of the first and second coolants is between 30°C and 50°C, with the temperature of the second coolant being lower than the temperature of the first coolant.The charging device further comprises a temperature control device for maintaining the temperature of the first storage unit and the second storage unit. The temperature control device comprises a heating device and a refrigeration unit. The heating device is thermally coupled exclusively to the first storage unit to heat the first coolant. The refrigeration unit is thermally coupled to both the first and second storage units, and is designed and arranged to extract thermal energy from the second storage unit and supply it to the first.

[0009] The design according to the invention allows the energy efficiency of the charging process of the traction battery to be increased, especially when a relatively low ambient temperature prevails.

[0010] Such a charging device can also be called a charging station and is used to charge the traction battery of an electrically powered vehicle, such as conventional electric vehicles or plug-in hybrids. The charging device acts as an interface between the power grid and the vehicle's traction battery.

[0011] Such a charging device can be designed to simultaneously charge several traction batteries of several motor vehicles and accordingly include several devices for establishing an electrical connection to the respective traction battery. Such a charging device can also be referred to as a charging station with multiple charging points, where one traction battery can be charged at each charging point.

[0012] To reduce high thermal stress on the traction battery, such charging devices are often equipped with an energy transfer unit that serves to dissipate thermal energy from the traction battery. These charging devices may also be equipped with a cooling device to cool the power electronics of the charging device.

[0013] The first coolant has a temperature between approximately 30°C and approximately 50°C, preferably approximately 40°C.

[0014] The first storage unit and the second storage unit serve to store thermal energy, which can be released at a later time.

[0015] The first storage unit and / or the second storage unit can be used to buffer the waste heat from the traction battery, which is generated when the traction battery is charged.

[0016] Through the thermal coupling of the first storage unit and the second storage unit with the vehicle's traction battery, energy can be transferred between the first storage unit and the second storage unit on the one hand, and the traction battery on the other.

[0017] The energy transfer device can, for example, comprise an energy transfer element through which an energy transfer medium flows. Furthermore, the energy transfer device can include suitable thermodynamic devices, such as heat exchangers, heat pumps, radiators, and fans.

[0018] The energy transfer device may have a contact surface that can be configured for thermal contact with the traction battery. Alternatively or additionally, heat transfer between the traction battery and the energy transfer device may occur through the exchange of a fluid between them, particularly if the traction battery has an integrated fluid-based cooling circuit.

[0019] The second coolant has a temperature between approximately 30°C and approximately 50°C, preferably approximately 40°C.

[0020] The second coolant has a temperature that is lower than the temperature of the first coolant.

[0021] The first coolant consists of water and / or glycol. The second coolant is a fossil fuel.

[0022] The invention further relates to a method for charging a traction battery of an electrically powered motor vehicle. The method comprises the following process steps: - Providing a charging device according to the invention; - Establishing an electrical connection between the charging device and the traction battery by means of the charging device's equipment; - thermal coupling of the first storage unit with the traction battery by means of the energy transfer device of the charging unit; and - Transfer of thermal energy from the first storage device to the traction battery via the energy transfer device when the temperature of the traction battery falls below a first temperature threshold.

[0023] The transfer of thermal energy between the first storage unit and the traction battery, and / or between the second storage unit and the traction battery, cannot be limited to the charging process. The traction battery to be charged can therefore be pre-conditioned and, in particular, heated before the charging process begins, in order to ensure a temperature throughout the entire charging process that enables efficient charging.

[0024] Alternatively or additionally, the traction battery can also be temperature-controlled after charging.

[0025] The traction battery temperature can be measured using a primary temperature sensor. This primary temperature sensor can be located on the charging device and positioned to detect the battery's temperature. Alternatively, it can be a temperature sensor on the vehicle itself, which can transmit the measured temperature to the charging device via a communication interface.

[0026] In a preferred embodiment, the procedure includes the following further procedural step: - Heating the first storage tank using the temperature control device when the temperature of the first storage tank falls below a second temperature threshold.

[0027] To measure the temperature of the first storage device, the charging device can be equipped with a second temperature sensor, which is arranged to detect the temperature of the first storage device and, in particular, the temperature of the first cooling medium.

[0028] Preferably the method includes the following additional process step: - Transfer of thermal energy from the traction battery to the first storage unit and / or from the traction battery to the second storage unit via the energy transfer device when the temperature of the traction battery exceeds a third temperature threshold.

[0029] In a preferred embodiment, the procedure includes the following further procedural step: - Cooling down the second storage tank using the temperature control device if the temperature of the second storage tank exceeds a fourth temperature threshold.

[0030] To measure the temperature of the second storage device, the charging device can be equipped with a third temperature sensor, which is arranged to detect the temperature of the second storage device and, in particular, the temperature of the second cooling medium.

[0031] Preferably the method includes the following additional process step: - Extracting thermal energy from the second storage unit, which is then supplied to the first storage unit.

[0032] In a preferred embodiment, thermal energy is extracted from the second storage unit and supplied to the first storage unit when the temperature of the first storage unit falls below the second temperature threshold and / or when the temperature of the second storage unit exceeds the fourth temperature threshold.

[0033] Details and further advantages of the charging device and the method according to the invention are explained below. This is illustrated by: Fig. 1: a schematic representation of a charging device not according to the invention; and Fig. 2: a schematic representation of a charging device according to the invention.

[0034] The invention relates to a charging device 20 for charging a traction battery 120 of an electrically powered motor vehicle 100 and a method for charging the traction battery 120 using the charging device 20.

[0035] The charging device 20 is equipped with a device for establishing an electrical connection to the traction battery 120, a first storage unit 30 for storing thermal energy, and an energy transfer device 50, which is thermally coupled to the first storage unit 30 and thermally connectable to the traction battery 120 for transferring thermal energy between the first storage unit 30 and the traction battery 120. The first storage unit 30 comprises a reservoir 32 filled with a first coolant. The first coolant has a temperature greater than 25°C.

[0036] The method according to the invention comprises the following process steps: - Providing a suitable charging device 20; - Establishing an electrical connection between the charging device 20 and the traction battery 20 by means of the charging device 20; - thermal coupling of the first storage unit 30 with the traction battery 120 by means of the energy transfer device 50 of the charging device 20; and - Transfer of thermal energy from the first storage 30 to the traction battery 120 by means of the energy transfer device 50 when the temperature of the traction battery 120 falls below a first temperature threshold.

[0037] The first temperature threshold can correspond to a temperature between approximately 20 °C and approximately 40 °C. Preferably, the first temperature threshold corresponds to a temperature of approximately 30 °C. Accordingly, the traction battery 120 is heated when its temperature falls below 30 °C.

[0038] The design can increase the energy efficiency of the charging process of the traction battery 120, especially when a relatively low ambient temperature prevails.

[0039] Such a charging device 20 can also be called a charging station and serves to charge a traction battery 120 of an electrically powered motor vehicle, such as conventional electric vehicles or plug-in hybrids. The charging device 20 represents an interface between the power grid and the traction battery of the motor vehicle. For this purpose, the charging device 20 can be equipped with a charging cable or a charging socket.

[0040] Such a charging device 20 can be designed for the simultaneous charging of several traction batteries 120 of several motor vehicles 100 and accordingly comprise several devices for establishing an electrical connection to the respective traction battery 120. Such a charging device 20 can also be referred to as a charging station with multiple charging points, wherein one traction battery 120 can be charged at each charging point.

[0041] To reduce high thermal loads on the traction battery 120, such charging devices 20 are often equipped with an energy transfer device that serves to dissipate thermal energy from the traction battery 120. Such charging devices 20 can also be equipped with a cooling device for cooling the power electronics of the charging device 20.

[0042] The charging device 20 further comprises a second storage unit 40 for storing thermal energy, wherein the second storage unit 40 comprises a reservoir 42 filled with a second coolant, and wherein the energy transfer device 50 is further thermally coupled to the second storage unit 40 and can be thermally coupled to the traction battery 120 for the purpose of transferring thermal energy between the second storage unit 40 and the traction battery 120.

[0043] Fig. Figure 1 shows a charging device 20 not according to the invention, with a single energy storage device, namely the first storage device 30. In contrast, Figure 1 shows a charging device 20 that does not conform to the invention, with a single energy storage device, namely the first storage device 30. Fig. 2 a charging device according to the invention with two separate energy storage devices, namely the first storage device 30 and the second storage device 40.

[0044] The energy transmission device 50 can include a coolant line 52 through which the first coolant and the second coolant can flow. The coolant line 52 can be connected to a heat exchanger 110 of the motor vehicle 100, as is particularly evident from the Fig. 1 and Fig. 2. The energy transfer device 50 can be thermally coupled to the traction battery 120 indirectly via the heat exchanger 110 of the motor vehicle 100.

[0045] The coolant line 52 is designed to selectively supply the energy transmission device 50 with either the first coolant or the second coolant. For this purpose, the coolant line 52 includes one or more valves 56. The valves 56 are connected, on the one hand, by fluid communication to the reservoir 32 of the first storage unit 30 and the reservoir 42 of the second storage unit 40, and on the other hand, by fluid communication to the heat exchanger 110 of the motor vehicle 100.

[0046] Reservoir 32 of the first storage facility 30 and / or reservoir 42 of the second storage facility 40 may be located above ground or underground. In particular, reservoir 32 of the first storage facility 30 may be located underground in cold regions and above ground in other regions. Furthermore, reservoir 42 of the second storage facility 40 may be located above ground in cold regions and underground in other regions.

[0047] The first coolant has a temperature between approximately 30°C and approximately 50°C, preferably approximately 40°C.

[0048] The second coolant has a temperature between approximately 30°C and approximately 50°C, preferably approximately 40°C.

[0049] The second coolant has a temperature that is lower than the temperature of the first coolant.

[0050] The charging device 20 can include a first temperature sensor that can be arranged on the traction battery 120 to detect the temperature of the traction battery 120.

[0051] To measure the temperature of the first storage 30, the charging device 20 can be provided with a second temperature sensor, which is arranged to detect the temperature of the first storage 30 and in particular the temperature of the first cooling medium.

[0052] To measure the temperature of the second storage device 40, the charging device 20 can be provided with a third temperature sensor, which is arranged in such a way as to detect the temperature of the second storage device and in particular the temperature of the second cooling medium.

[0053] The first coolant consists of water and / or glycol. The second coolant is a fossil fuel.

[0054] The charging device 20 further comprises a temperature control device 60 for temperature control of the first storage unit 30 and for temperature control of the second storage unit 40. The temperature control device 60 comprises a heating device 62 and a refrigeration unit 64. The heating device 62 can, in particular, be an inductive heating device.

[0055] The chiller 64 is thermally coupled to the first storage 30 and to the second storage 40, wherein the chiller 64 is designed and arranged to extract thermal energy from the second storage 40 and supply it to the first storage 30.

[0056] The transfer of thermal energy between the first storage unit 30 and the traction battery 120, and between the second storage unit 40 and the traction battery 120, cannot be limited to the charging process. The traction battery 120 to be charged can therefore be pre-conditioned and, in particular, heated before the start of the charging process to ensure a temperature of the traction battery 120 throughout the entire charging process that enables efficient charging.

[0057] Alternatively or additionally, the traction battery can also be temperature-controlled after charging.

[0058] The procedure may include the following additional procedural step: - Heating the first storage tank 30 by means of the temperature control device 60 when the temperature of the first storage tank 30 falls below a second temperature threshold.

[0059] The second temperature threshold can correspond to a temperature between approximately 20 °C and approximately 40 °C. Preferably, the second temperature threshold corresponds to a temperature of approximately 30 °C. Accordingly, the first storage tank is heated when its temperature falls below 30 °C.

[0060] The second temperature threshold can be the same as the first temperature threshold.

[0061] Heating the first storage tank 30 may include heating the first coolant.

[0062] The procedure may include the following additional procedural step: - Transfer of thermal energy from the traction battery 120 to the first storage 30 and / or from the traction battery 120 to the second storage 40 by means of the energy transfer device 50, when the temperature of the traction battery 120 exceeds a third temperature threshold.

[0063] The third temperature threshold can correspond to a temperature between approximately 20 °C and approximately 40 °C. Preferably, the third temperature threshold corresponds to a temperature of approximately 30 °C. Accordingly, the traction battery 120 is cooled when its temperature exceeds 30 °C.

[0064] The procedure may include the following additional procedural step: - Cooling down the second storage tank 40 by means of the temperature control device 60 when the temperature of the second storage tank 40 exceeds a fourth temperature threshold.

[0065] The fourth temperature threshold can correspond to a temperature between approximately 20 °C and approximately 40 °C. Preferably, the fourth temperature threshold corresponds to a temperature of approximately 30 °C. Accordingly, the second storage tank 40 is cooled when its temperature exceeds 30 °C.

[0066] The fourth temperature threshold can be the same as the third temperature threshold.

[0067] Cooling down the second storage unit 40 may include cooling down the second coolant.

[0068] The procedure may include the following additional procedural step: - Extracting thermal energy from the second storage tank 40, which is then supplied to the first storage tank 30.

[0069] In a preferred embodiment, thermal energy is extracted from the second storage tank 40 and supplied to the first storage tank 30 when the temperature of the first storage tank 30 falls below the second temperature threshold and / or when the temperature of the second storage tank 40 exceeds the fourth temperature threshold.

[0070] By means of the charging device 20 and by means of the method, an increase in the integral charging efficiency of the charging device 20 can be achieved, especially in fast charging processes of traction batteries 120 of electrically powered motor vehicles 100.

[0071] In fast-charging processes, the traction battery 120 is charged over a short charging period. High currents flow between the charging station 20 and the traction battery 120. Due to the battery layout of conventional traction batteries 120, increasing the charging voltage is generally unsuitable for shortening the charging time. The high currents result in significant power losses during the charging process, as power loss is proportional to the square of the current. This high power loss generates considerable heat, necessitating external cooling and / or heat dissipation from the traction battery 120.

[0072] On the other hand, fast charging capability is only available from a traction battery temperature of approximately 30 °C. Therefore, it may be necessary to heat the traction battery 120 before and / or during a charging process.

[0073] If the motor vehicle 100 arrives at the charging device 20 with a traction battery temperature of approximately 10 °C, it is necessary to heat up the traction battery 120 before a fast charging process can be initiated.

[0074] Reservoir 32 of the first storage facility 30 and reservoir 42 of the second storage facility 40 can have a volume of approximately 3 m³. 3 include, in particular, a volume of approximately 3 m³ 3 for each charging point present on the charging device 20. For example, the reservoir 32, 42 of a charging device 20 with two charging points would have a volume of approximately 6 m³. 3 .

[0075] The first coolant can be composed of 90% water and 10% glycol.

[0076] Reservoir 42 of the second storage system 40 is formed by a fuel tank of a filling station. Such a fuel tank has an exemplary volume of approximately 3 m³. 3An input of approximately 10 MJ can result in a temperature change of approximately 2.5 °C.

[0077] The first storage tank 30, and especially the first coolant, can have a temperature of approximately 40°C.

[0078] The traction battery 120, for example, can be heated to approximately 30 °C. The initial temperature threshold can also be approximately 30 °C. Heating the traction battery from 10 °C to 30 °C can correspond to a heating power of approximately 10 MJ. Accordingly, during this heating process, the temperature of the first coolant drops from 40 °C to 39 °C. At the end of the heating process, a temperature difference of 9 °C remains between the traction battery 120 and the first coolant.

[0079] During the charging process of traction battery 120, its temperature can rise to approximately 50°C. At this point, the previously extracted heating power of approximately 10 MJ can be drawn from traction battery 120 once its temperature reaches approximately 39°C and fed back into the first storage tank 30, thereby heating the first coolant from 39°C to 40°C.

[0080] It is advantageous if the permissible temperature range of the traction battery 120 is at least twice as high as the temperature loss during heat transfer due to the thermal resistance between the traction battery 120 and the first storage 30.

[0081] By means of the temperature control device 60, the first storage unit 30 can be conditioned, i.e. prepared for a heating process of the traction battery 120 and a subsequent charging process of the traction battery 120.

[0082] Fig. Figure 2 shows the charging device 20. The charging device 20 of the Fig. The device 2 is equipped with a first storage unit 30 and a second storage unit 40. The first storage unit 30 and the second storage unit 40 have different temperatures. The first storage unit 30 has a higher temperature than the second storage unit 40.

[0083] According to the Fig. 2. The two storage units 30 and 40 represent two different thermal inertias, which are thermally linked to each other, in particular by the refrigeration unit 64. The temperature control device 60 also includes the heating device 62, in particular an inductive heating device, which is designed to heat the first coolant.

[0084] According to one possible embodiment of the charging device and / or the method, the interior of the motor vehicle 100 can be heated simultaneously with the heating of the traction battery 120. This means that thermal energy is transferred from the first storage device 30 to the interior, preferably by means of the energy transfer device 50, when the temperature of the interior falls below a certain temperature threshold.

[0085] Preferably, a phase change of the first coolant and / or the second coolant can also be used to store the thermal energy.

[0086] The first storage tank 30 can, for example, be thermally coupled to a solar thermal system and / or a brine heat pump and / or a building services system of a rest stop.

Claims

[1] Charging device for charging a traction battery (120) of an electrically powered motor vehicle (100), with a device for establishing an electrical connection to the traction battery (120), with a first storage device (30) for storing thermal energy, wherein the first storage (30) comprises a reservoir (32) filled with a first coolant, which is water and / or glycol and has a temperature between 30°C and 50°C, with a second storage device (40) for storing thermal energy, wherein the second storage (40) is a fuel tank of a petrol station and comprises a reservoir (42) filled with a second coolant, which is a fossil fuel and has a temperature which is between 30°C and 50°C and is lower than the temperature of the first coolant, with an energy transmission device (50) having a coolant line (52), wherein the energy transmission device (50) for transmitting thermal energy between the first storage device (30) and the traction battery (120) is thermally coupled to the first storage device (30) and can be thermally coupled to the traction battery (120), and wherein the energy transmission device (50) is further thermally coupled to the second storage device (40) and can be thermally coupled to the traction battery (120) for the transmission of thermal energy between the second storage device (40) and the traction battery (120), wherein the coolant line (52) is designed to selectively supply the energy transmission device (50) with either the first coolant or the second coolant and comprises at least one valve (56) which, on the one hand, is fluidly connected to the reservoir (32) of the first accumulator (30) and the reservoir (42) of the second accumulator (40) and, on the other hand, is fluidly connected to a heat exchanger (110) of the motor vehicle (100), with a temperature control device (60) for temperature control of the first storage (30) and for temperature control of the second storage (40), wherein the temperature control device (60) comprises a heating device (62) which is thermally coupled exclusively to the first storage device (30) in order to heat the first coolant, wherein the temperature control device (60) further comprises a refrigeration machine (64) which is thermally coupled to the first accumulator (30) and to the second accumulator (40), which represent two different thermal inertias, and which is designed and arranged to extract thermal energy from the second accumulator (40) and to supply it to the first accumulator (30). [2] Method for charging a traction battery (120) of an electrically powered motor vehicle (100) comprising the following method steps: - Providing a charging device (20) according to claim 1; - establishing an electrical connection between the charging device (20) and the traction battery (20) by means of the device of the charging device (20); - thermal coupling of the first storage device (30) and the second storage device (40) to the traction battery (120) by means of the energy transmission device (50) of the charging device (20); and - Transferring thermal energy from the first storage device (30) to the traction battery (120) by means of the energy transfer device (50) when a temperature of the traction battery (120) falls below a first temperature threshold value. [3] Method according to claim 2, comprising the following method step: Heating the first storage (30) by means of the temperature control device (60) when a temperature of the first storage (30) falls below a second temperature threshold value. [4] Method according to claim 2 or 3, comprising the following method step: Transferring thermal energy from the traction battery (120) to the first storage device (30) and / or from the traction battery (120) to the second storage device (40) by means of the energy transfer device (50) when the temperature of the traction battery exceeds a third temperature threshold value. [5] Method according to claim 2, 3 or 4, comprising the following method step: Cooling down the second storage (40) by means of the temperature control device (60) when the temperature of the second storage exceeds a fourth temperature threshold. [6] Method according to one of claims 2 to 5, comprising the following method step: Extracting thermal energy from the second storage device (40) which is supplied to the first storage device (30) when the temperature of the first storage device (30) falls below the second temperature threshold and / or when the temperature of the second storage device (40) exceeds the fourth temperature threshold.

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