Battery unit for an electrically driven vehicle, electric vehicle and charging station comprising a battery unit and method for operating a battery unit

Abstract

Battery unit for an electrically driven vehicle, electric vehicle and charging station comprising a battery unit and method for operating a battery unit Battery unit (1) for an electrically driven vehicle, comprising - a number of battery modules (2) providing a direct current, - an inverter (11) configured to convert a direct current from the battery modules (2) to an alternating current for an electric motor (3), - a number of first terminals (7) configured to connect the battery unit (1) to the electric motor (3), - a number of second terminals (8) configured to connect the battery unit (1) to a charging unit (6), - a number of third terminals (9) configured to connect the battery unit (1) to external inductances, wherein the battery modules (2), the inverter (11) and the terminals are arranged in a common housing (20).

Description

[0001] Description

[0002] Battery unit for an electrically driven vehicle, electric vehicle and charging station comprising a battery unit and method for operating a battery unit

[0003] The present disclosure relates to a battery unit for electrically driven vehicles. Specifically, the present disclosure pertains to a battery unit comprising multiple battery modules, an inverter for converting direct current to alternating current, and various terminals for connecting to an electric motor and a charging unit.

[0004] In the field of electrically driven vehicles, battery units are used to store and supply electrical energy necessary for vehicle propulsion. These systems generally include a multitude of battery modules that provide direct current (DC), an inverter to convert the DC to alternating current (AC) for the electric motor, and various terminals to connect the battery unit to the motor, charging units, and other external components. Terminals and associated switches may be arranged in a so-called junction box, wherein the inverter is arranged between the junction box and the electric motor. Despite these established configurations, the integration of these components into a cohesive and efficient system remains a challenge.

[0005] Furthermore, second life applications for battery units are becoming increasingly more important to reduce the CO2 footprint of electric vehicles. One possible application for the reuse of battery units is to use them as storage systems for energy produced by renewable sources such as wind and solar at peak periods. Such storage systems can in particular be assigned to charging stations for electric vehicles to provide extra capacity for fast charging.

[0006] With known solutions, however, used batteries cannot be connected in series or parallel due to the fact that they differ in terms of capacity, power and voltage because they originate from different vehicles and have different usage profiles. Therefore, the state-of-health and the state-of-charge are expected to have a wide range. In order to prevent the mismatch between batteries, DCDC power electronic converters are used to regulate the voltage of each battery and to control the charging / discharging power and current.

[0007] This, however, is not cost-efficient, because a DCDC converter is needed for every battery. A means to reduce the cost is to use multi-input DCDC converters, where every DCDC can handle more than one battery. However, this increases the complexity of the system considerably.

[0008] It is therefore an object of the present invention to provide a battery unit for electrically driven vehicles that overcomes the disadvantages of known systems and in particular can be used in second life applications cost-efficiently and safely.

[0009] According to the present invention, these objects are addressed by the features of the independent claim 1. In addition, further advantageous embodiments follow from the dependent claims and the description.

[0010] According to an aspect of the invention, a battery unit for an electrically driven vehicle is provided, which comprises a number of battery modules providing a direct current, an inverter configured to convert the direct current from the battery modules to an alternating current for an electric motor, a number of first terminals configured to connect the battery unit to the electric motor, a number of second terminals configured to connect the battery unit to a charging unit, and a number of third terminals configured to connect the battery unit to external inductances. The battery modules, the inverter and the terminals are arranged in a common housing.

[0011] The battery unit has the advantage, that reuse of the battery unit in second life applications is facilitated considerably. This is possible because the third terminals can be connected to the first terminals via external inductances, wherein the term “external” denotes, that the inductances are arranged outside the common housing. The inductances and inverter bridges may be used in second life applications as a DCDC converter to connect different battery units.

[0012] To achieve this, in the case of an inverter comprising three half-bridges, each half-bridge is connected to one first terminal and via an inductance to a third terminal. The result is a buck / boost converter functionality in the second life application.

[0013] The external inductances could also be arranged inside the housing. However, since the DCDC converter functionality is in particular advantageous in second life applications, to provide inductances already for first life applications may be considered unnecessary. According to an embodiment, the battery unit further includes a switch DCB arranged within the common housing. This switch DCB is configured to connect the battery unit to or disconnect it from the third terminals. The specific mechanism of communication between the switch DCB and the third terminals involves an electrical connection that can be controlled to either establish or interrupt the flow of current to the external inductances. This switch can be operated in an open or closed state, where the open state corresponds to the disconnection of the battery unit from the third terminals, effectively isolating the external inductances from the battery unit, and the closed state corresponds to the connection of the battery unit to the third terminals, allowing current to flow to the external inductances.

[0014] The switch DCB can be operated to switch the battery unit from a first life application to a second life application. The switch DCB stays open during first life use of the battery unit in an electric vehicle but is closed to establish a connection between the battery units and the DCDC converter in second life applications.

[0015] According to a further embodiment, the battery unit further comprises a switch DCC arranged in the common housing. The inclusion of the switch DCC introduces a specific mechanism of communication between the battery unit and the second terminals, which are configured to connect the battery unit to a charging unit. The switch DCC is configured to connect the battery unit to or disconnect it from the second terminals. This feature allows for the selective engagement or disengagement of the battery unit from the charging unit and allows selection of a driving mode or alternatively a charging mode of the vehicle.

[0016] According to a further embodiment, the battery unit further comprises a number of fourth terminals configured to connect the battery unit to high-voltage (HV) auxiliaries. The inclusion of these fourth terminals enables power transfer between the battery unit and various HV auxiliary systems, such as air conditioning compressors, electric power steering systems, and other high-voltage components that are essential for the operation of an electrically driven vehicle. This additional feature ensures that the battery unit can serve as a centralized power source for multiple high-voltage systems within the vehicle, thereby enhancing the overall efficiency and integration of the vehicle's electrical architecture.

[0017] Moreover, the embodiment includes a switch DCA arranged within the common housing, which is configured to connect the battery unit to or disconnect it from the fourth terminals. The switch DCA serves as a critical control mechanism that allows for the selective engagement or disengagement of the battery unit with the HV auxiliaries. This switch provides a means of managing the power distribution and ensuring safety by allowing the disconnection of high-voltage components when necessary, such as during maintenance or in the event of a fault.

[0018] According to a further aspect of the invention, an electric vehicle is provided comprising the battery unit that includes a number of battery modules providing a direct current, an inverter configured to convert the direct current from the battery modules to an alternating current for an electric motor, a number of first terminals configured to connect the battery unit to the electric motor, a number of second terminals configured to connect the battery unit to a charging unit, and a number of third terminals configured to connect the battery unit to external inductances, all arranged within a common housing.

[0019] According to a further aspect of the invention, a charging station is provided comprising a number of battery units, each incorporating a number of battery modules described above, wherein the first terminals are connected to the third terminals via inductances, in particular via a stator of an electric motor.

[0020] The charging station has the advantage that battery units from electrically driven vehicles may be reused in the charging station as energy storage cost-efficiently. It is not necessary to provide a separate DCDC converter for each battery unit, because the inverter of each battery unit together with the inductances connecting the first and third terminals provide the DCDC functionality. According to this embodiment, the stator of the electric motor from the vehicle, in which the battery unit was used during its first life, is employed as an external inductance. This has the advantage that no extra inductance has to be provided. This embodiment is advantageous in cases, where the design of the electric motor makes it possible to take out the stator.

[0021] Alternatively, the first terminals can be connected to the third terminals via external inductances. This embodiment has the advantage that it can be employed regardless of the design of the electric motor and / or in cases where the electric motor is intended to still being used in its first life application.

[0022] This aspect introduces a charging station that integrates multiple battery units, thereby enhancing the overall energy storage capacity and providing a more robust and scalable solution for charging electrically driven vehicles. According to a further aspect of the invention, a method for operating the battery unit is provided, wherein it is determined if the battery unit is currently in a first life- or a second life-application, and the switch DCB is operated depending on the result, so that the switch DCB is in an open state, if the battery unit is in a first life-application, and that the switch DCB is in a closed state, if the battery unit is in a second life-application.

[0023] With this method it is determined if the DCDC functionality of the inverter and external inductances are required. If the battery unit 1 is in a second life usage application, the switches DCB, INV and DCC- are closed and the switches DCC+ and DCA are open to enable the described second life usage of the battery unit 1 with the DCDC functionality of the inverter and external inductances.

[0024] If a first life usage application is determined, it can furthermore be determined whether the vehicle is in a driving mode or not. If the vehicle is in a driving mode, the switches INV and DCA are closed and the switches DCC and DCB are open, which means that the third terminals are not connected to the battery modules and that the second terminals for connection of a charging unit are not connected to the battery modules, but that the inverter is connected to the battery modules and by that the electric motor, enabling the battery unit to drive the electric motor.

[0025] If it is determined that the vehicle is not in a driving mode, it has to be in a charging mode. Therefore, the switches DCC and DCA are closed thereby connecting the battery modules to the second terminals for a charging unit. The switches INV and DCB are open to disconnect the electric motor.

[0026] Embodiments of the invention are described with reference to schematic drawings.

[0027] Figure 1 shows a battery unit according to an embodiment of the invention in a first life application,

[0028] Figure 2 shows details of the battery unit of figure 1 according to a first embodiment of the invention,

[0029] Figure 3 shows battery units according to the first embodiment in a second life application, Figure 4 shows details of the battery unit of figure 1 according to a second embodiment of the invention,

[0030] Figure 5 shows battery units according to the second embodiment in a second life application and

[0031] Figure 6 shows a diagram of a method for operating the battery unit according to figure 1 .

[0032] Figure 1 shows a battery unit 1 for an electrically driven vehicle. The battery unit 1 comprises a number of battery modules 2 which provide a direct current for an electric motor 3 of the vehicle. To convert the direct current to an alternating current, the battery unit 1 further comprises an inverter, which is part of a unit denoted here as the battery integrated box 4. The battery integrated box 4 may have a housing within the common housing 20 of the battery unit 1 . Alternatively, elements of the battery integrated box 4 may be arranged distributedly or grouped together within the housing 20.

[0033] The battery integrated box 4 furthermore comprises switches, which have so far been allocated in the so-called junction box, and the battery management system.

[0034] The battery unit 1 and the battery integrated box 4 with the inverter are arranged in the common housing 20.

[0035] The housing 20 furthermore comprises a number of terminals for the connection of the battery unit 1 to external units. In particular, the battery unit 1 comprises a number of first terminals 7 configured to connect the battery unit 1 to the electric motor 3 of the vehicle and a number of second terminals 8 to connect the battery unit 1 to a charging unit 6. Furthermore, the battery unit 1 comprises a number of third terminals 9 configured to connect the battery unit 1 to external inductances and a number of fourth terminals 10 configured to connect the battery unit 1 to high voltage (HV) auxiliaries 5.

[0036] Figure 2 shows the battery integrated box 4 of the battery unit in more detail. The battery integrated box 4 comprises the inverter 11 comprising in particular number of power semiconductor devices to convert the direct current from the battery modules to an alternating current for the electric motor. The inverter 11 is connected to the battery modules via a switch INV which can be closed to connect the battery modules to the inverter 11 and opened to disconnect them.

[0037] Furthermore, the battery integrated box 4 comprises a switch DCC to connect the battery units 1 to or disconnected from the second terminals 8 and thereby to connect the battery unit to or disconnect it from a charging unit.

[0038] Furthermore, the battery integrated box 4 comprises a switch DCB configured to connect the battery unit to or disconnected from the fourth terminals 10 and thereby connect the battery unit to or disconnect it from HV auxiliaries.

[0039] In the first life application of the battery unit in an electrically driven vehicle, the switches INV, DCC and DCA are operated to select an operation mode for the battery unit, in particular a driving mode, a charging mode and the supply of HV auxiliaries.

[0040] In order to enable second life applications of the battery unit, the battery integrated box 4 further comprises a switch DCB which connects the battery modules to third terminals 9. In a second life application as shown in figure 2, the third terminals 9 and the first terminals 7 are connected via external inductances 12. The external inductances 12 are connected to the bridges of the inverter 11 in second life applications to allow DCDC functionality of the battery unit.

[0041] The DCDC functionality of the battery unit makes it possible to operate a plurality of battery units in a charging station without having to provide a DCDC converter for ever battery unit.

[0042] Figure 3 shows a number of battery units 1 in a second life application enabled by this DCDC functionality. According to figure 3, a multitude of battery units 1 , each having first terminals and third terminals connected via external inductances 12, are connected in parallel to a charging station 13, which is furthermore connected to the grid 14 and provides a number of charging outlets 15 for electrically driven vehicles. The battery units 1 contribute to the charging power provided by the charging station 13 and can be charged in particular if there is a surplus of renewable energy.

[0043] The battery units 1 according to figure 3 may all have different states-of-health and states-of-charge and can be charged by a wide range of voltages and can support the charged vehicles with different voltage levels thanks to the DCDC functionality provided by the combination of the external inductances 12 and the bridges of the inverter.

[0044] Figure 4 shows a second embodiment of a second life application of the battery units 1 . According to this embodiment, the stator 16 of the electric motor 3 from the first life application is used as an inductance to provide DCDC functionality in the second life application. According to the embodiment shown in figure 4, the stator terminals are collected together to simplify the connection to the third terminal 9. According to this embodiment, a design for the electric motor 3 is chosen which allows to take out the rotor so that the stator 16 can then be connected to the battery integrated box 4 and achieve the DCDC back / boost functionality.

[0045] Figure 5 shows the charging station 13 connected to the grid 14 with the charging outlets 15 and with the battery units 1 connected to the stators 16 according to this second embodiment.

[0046] Figure 6 in connection with Figures 1 to 5 shows a schematic diagram of a method for operating the battery unit 1 . In a first step 100, it is determined whether the battery unit 1 is in a first life usage application. If not, the switches DCB, INV and DCC- are closed and the switches DCC+ and DCA are open to enable the described second life usage of the battery unit 1 .

[0047] If a first life usage application is determined, the next step 200 determines whether the vehicle is in a driving mode or not. If the vehicle is in a driving mode, the switches INV and DCA are closed and the switches DCC and DCB are open, which means that the third terminals 9 are not connected to the battery modules 2 and that the second terminals 8 for connection of a charging unit are not connected to the battery modules 2, but that the inverter 11 is connected to the battery modules 2 and by that the electric motor 3. Furthermore, the HV auxiliaries 5 are connected to the battery modules 2.

[0048] If it is determined that the vehicle is not in a driving mode, it has to be in a charging mode. Therefore, the switches DCC and DCA are closed thereby connecting the battery modules 2 to the second terminals 8 for a charging unit. The switches INV and DCB are open to disconnect the electric motor 3. List of reference symbols

[0049] 1 battery unit

[0050] 2 battery modules

[0051] 3 electric motor

[0052] 4 BIB

[0053] 5 HV auxiliaries

[0054] 6 charging unit

[0055] 7 first terminal

[0056] 8 second terminal

[0057] 9 third terminal

[0058] 10 fourth terminal

[0059] 11 inverter

[0060] 12 external inductance

[0061] 13 charging station

[0062] 14 grid

[0063] 15 charging outlet

[0064] 16 stator

[0065] 20 housing

[0066] 100 step

[0067] 200 step

Claims

Claims1 . Battery unit (1 ) for an electrically driven vehicle, comprising- a number of battery modules (2) providing a direct current,- an inverter (11 ) configured to convert a direct current from the battery modules (2) to an alternating current for an electric motor (3),- a number of first terminals (7) configured to connect the battery unit (1 ) to the electric motor (3),- a number of second terminals (8) configured to connect the battery unit (1 ) to a charging unit (6),- a number of third terminals (9) configured to connect the battery unit (1 ) to external inductances, wherein the battery modules (2), the inverter (11 ) and the terminals are arranged in a common housing (20).

2. Battery unit (1 ) according to claim 1 , further comprising a switch DCB arranged in the common housing (20) and configured to connect the battery modules (2) to or disconnect it from the third terminals (9).

3. Battery unit (1 ) according to claim 1 or 2, further comprising a switch DCC arranged in the common housing (20) and configured to connect the battery modules (2) to or disconnect it from the second terminals (8).

4. Battery unit (1 ) according to any of claims 1 to 3, further comprising a number of fourth terminals (10) configured to connect the battery unit (1 ) to HV auxiliaries and a switch DCA arranged in the common housing (20) and configured to connect the battery modules (2) to or disconnect it from the fourth terminals (10).

5. Electric vehicle comprising a battery unit (1 ) according to any of claims 1 to 4.

6. Charging station (13) comprising a number of battery units (1 ) according to any of claims 1 to 4, wherein the first terminals (7) are connected to the third terminals (9) via a stator7. Charging station (13) comprising a number of battery units (1 ) according to any of claims 1 to 4, wherein the first terminals (7) are connected to the third terminals (9) via external inductances.

8. Method for operating a battery unit (1 ) according to claim 2, wherein it is determined if the battery unit (1 ) is currently in a first life- or a second life-application, and the switch DCB is operated depending on the result, so that the switch DCB is in an open state, if the battery unit (1 ) is in a first life-application, and that the switch DCB is in a closed state, if the battery unit (1 ) is in a second life-application.

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