System for a Drive Energy Store of a Hybrid or Electric Vehicle, and Method for Charging a Drive Energy Store of a Hybrid or Electric Vehicle

Abstract

A system for a drive energy store of a hybrid or electric vehicle is provided. The system includes a receiver which is designed to receive state information of the drive energy store, the state information specifying whether a defect is present or imminent in the drive energy store; and a charging controller, which is designed to adjust a maximum charging voltage and/or a maximum state of charge for a charging process of the drive energy store by a recovery mechanism and/or a load point shift and/or an external charging station to a reduced value if the state information indicates that the defect is imminent.

Claims

1.-10. (canceled)

11. A system for a drive energy store of a hybrid or electric vehicle, the system comprising: a receiver that receives status information for the drive energy store, wherein the status information indicates whether a defect in the drive energy store is imminent; and a charging controller that sets at least one of a maximum charging voltage and a maximum state of charge for a charging process of the drive energy store via at least one of a recovery mechanism, a load point displacement, and an external charging station to a reduced value, when the status information indicates that the defect is imminent.

12. The system according to claim 11, wherein the charging controller sets the maximum charging voltage for the charging process to a normal value, which is greater than the reduced value, when the status information indicates that no defect is imminent, wherein the normal value of the maximum charging voltage lies within the range of 2.8 volts to 4.2 volts.

13. The system according to claim 11, wherein the charging controller adjusts the maximum state of charge from a normal value to the reduced value, which is lower than the normal value, when the status information indicates that the defect is imminent, wherein the normal value is 90% or more of a maximum possible charge of the drive energy store, and the reduced value is less than 90% of the maximum possible charge.

14. The system according to claim 11, wherein the charging controller discharges the drive energy store, by one or more electrical loads of the vehicle, when the status information indicates that the defect is imminent.

15. The system according to claim 11, further comprising an output device that outputs information concerning at least one of the defect and a reduced maximum possible range for attention of a user.

16. The system according to claim 11, further comprising a monitoring device that monitors a state of the drive energy store and to deliver status information.

17. The system according to claim 16, wherein the monitoring device detects one or more of the following variables: a cell voltage of cells of the drive energy store, a current flowing through the cell of the drive energy store, a cell temperature of cells of the drive energy store, an internal cell pressure of cells of the drive energy store, an insulation resistance of a battery system which comprises the drive energy store, and a fullness level of a coolant circuit for the drive energy store.

18. The system according to claim 12, wherein the charging controller adjusts the maximum state of charge from the normal value to the reduced value, which is lower than the normal value, when the status information indicates that the defect is imminent, wherein the normal value is 90% or more of a maximum possible charge of the drive energy store, and the reduced value is less than 90% of the maximum possible charge.

19. The system according to claim 12, wherein the charging controller discharges the drive energy store, by one or more electrical loads of the vehicle, when the status information indicates that the defect is imminent.

20. The system according to claim 12, further comprising an output device that outputs information concerning at least one of the defect and a reduced maximum possible range for attention of a user.

21. The system according to claim 12, further comprising a monitoring device that monitors a state of the drive energy store and to deliver status information.

22. A hybrid or electric vehicle, comprising the system according to claim 11.

23. A method for charging a drive energy store of a hybrid or electric vehicle, the method comprising: detecting status information of the drive energy store, wherein the status information indicates whether a defect is imminent in the drive energy store; and setting at least one of a maximum charging voltage and a maximum state of charge for a charging process of the drive energy store via at least one of a recovery mechanism, a load point displacement, and an external charging station to a reduced value, when the status information indicates that the defect is imminent.

24. A non-transitory computer-readable medium containing a software program, which when executed by a processor, executes the method according to claim 23.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Exemplary embodiments of the disclosure are represented in the figures, and are described in greater detail hereinafter. In the figures:

[0031] FIG. 1 shows a system for a drive energy store of a hybrid or electric vehicle, according to embodiments of the present disclosure, and

[0032] FIG. 2 shows a flow diagram of a method for charging a drive energy store of a hybrid or electric vehicle, according to embodiments of the present disclosure.

DETAILED DESCRIPTION OF THE DRAWINGS

[0033] Hereinafter, unless indicated otherwise, the same reference symbols are employed for identical or identically functioning elements.

[0034] FIG. 1 shows a system for a drive energy store 110 of a hybrid or electric vehicle 100 according to embodiments of the present disclosure. Depending upon the embodiment, the hybrid or electric vehicle 100 can be an exclusively electric vehicle (BEV) or a plug-in hybrid vehicle (PHEV).

[0035] The system comprises a receiving device 120, which is designed to receive status information for the drive energy store 110. The status information indicates whether a defect in the drive energy store 110 is imminent.

[0036] The defect can be a short-circuit between the electrodes of a cell of the drive energy store 110, associated with a foreign particle. The drive energy store 110 can be, for example, a lithium-ion battery having a plurality of cells.

[0037] Status information can be detected by means of a monitoring device. The monitoring device can monitor a plurality of cells of the drive energy store, and determine the status thereof. The monitoring device can be designed, for example, to detect a cell voltage and/or a current flowing through the cell and/or a cell temperature (e.g., an internal cell temperature and/or an external cell temperature) and/or an internal cell pressure. In some forms of embodiment, at least one of the above-mentioned variables can be detected over a period of time. The status of the cell can be deduced from variations over said period of time.

[0038] For example, an open-circuit cell voltage can be measured during a stoppage of the vehicle. The status of the cell can be concluded from a variation in the open-circuit cell voltage. If, for example, a decline in the open-circuit cell voltage over a predefined time period exceeds a predefined threshold value, it can be concluded that a cell defect is potentially imminent.

[0039] Additionally or alternatively, the monitoring device can comprise a sensor system for the detection of an insulation resistance of the battery system (e.g., battery cells and/or the sensor system and/or electronics and/or coolers, etc.) and/or for the detection of a fullness level in the coolant circuit of the vehicle. By means of this sensor system, a leak in the battery cooler can be detected, which can also result in a cell defect, and particularly in a short-circuit.

[0040] The system further comprises a charging control device 130, which is designed to set a maximum charging voltage and/or a maximum state of charge for a charging process of the drive energy store 100, for example, by means of a recovery mechanism 140, to a reduced value, if the status information indicates that a defect is imminent. The term “reduced value” signifies that the value is lower, in comparison with values which are employed in a normal situation, i.e., in the absence of an impending cell defect.

[0041] The receiving device 120 and the charging control device 130 can be embodied in a combined software and/or hardware module. Alternatively, the receiving device 120 and the charging control device 130 can be embodied in separate software and/or hardware modules.

[0042] In some embodiments, the charging control device 130 can be designed to set the value of the maximum charging voltage and/or of the maximum state of charge for a charging process of the drive energy store 110 to a normal value, which is greater than the reduced value, if the status information indicates that no defect is imminent. Thus, in a normal state, standard values and, in a risk state, reduced values in comparison with the standard values can be employed for the maximum charging voltage and/or the maximum state of charge.

[0043] Typically, the normal value for the maximum charging voltage lies within a range of 2.8 volts to 4.2 volts. The reduced value of the maximum charging voltage per cell can lie within the range of 3 to 4 volts, and particularly within the range of 3.5 to 3.7 volts. For example, the reduced value of the maximum charging voltage per cell can be 3.616 volts. In this example, the charging voltage defines a cell voltage which is generated by an individual cell. In particular, the cell voltage can be an open-circuit cell voltage. This voltage is higher, the higher the state of charge of the cell. In other words, the charging voltage correlates to the state of charge.

[0044] The charging control device 130 can further be designed to adjust the maximum state of charge (SoC) from a first value (e.g., a standard value) to a second value, which is lower than the first value, if the status information indicates that a defect is imminent. The first value can be, for example, 90% or more of a maximum charge of the drive energy store 110. For example, in standard operation, lithium-ion batteries are not fully charged (i.e., charged to 100%), as the charging time for the final few percent increases substantially. Additionally or alternatively, the second value can be lower than 90% of the maximum charge of the drive energy store 110.

[0045] The charging control device 130 can further be designed to discharge the drive energy store 110 by means of one or more electrical loads of the vehicle 100, when the status information indicates that a defect is imminent. This can particularly occur if an actual charging voltage and/or an actual state of charge, at the time of detection of the impending defect, exceeds the reduced values of the maximum charging voltage or the maximum state of charge. In such a case, the drive energy store can be actively discharged, in order to restore the charging voltage and/or the state of charge to a safe range.

[0046] The vehicle 100 can be, for example, a hybrid vehicle having a mechanism for load point displacement. Load point displacement can be employed for the active and prompt discharging of the drive energy store 110, in the event of the detection of an impending defect.

[0047] In some embodiments, the charging control device 130 is designed to set the maximum charging voltage and/or the maximum state of charge for a charging process of the drive energy store by means of an external charging station to the reduced value, if the status information indicates that a defect is imminent.

[0048] Charging of the drive energy store by means of an external charging station is schematically represented in FIG. 1. The hybrid or electric vehicle 100 can be connected by means of a connecting device, e.g., a charging cable or power cable 16, to a power terminal 14 which is arranged on a charging column 12, e.g., a plug socket. The power terminals or charging columns can be connected by means of a power line to a network connection of a power grid of an electric utility company (not represented).

[0049] In some embodiments, communication between the hybrid or electric vehicle 100 and the charging column 12 can be executed wirelessly, for example, by means of WLAN, Bluetooth, infrared, GSM, UMTS or similar. Wired communication, for example, via the charging cable, is also possible.

[0050] The system can further comprise an output device for the delivery of a user instruction, for example a display. The user instruction can relate to the impending defect. In particular, an instruction can be issued to the user to the effect that a workshop should be contacted for the replacement of the risk-affected cell or of a cell module with the risk-affected cell. Overall damage to the drive energy store 110 can be prevented accordingly. The output device can further be designed, e.g., to indicate the maximum possible range, which is reduced by the restriction of the charging voltage, for example on the display.

[0051] FIG. 2 shows a flow diagram of a method 200 for charging a drive energy store of a hybrid or electric vehicle, according to forms of embodiment of the present disclosure.

[0052] The method 200, in block 210, comprises a detection of status information for the drive energy store, wherein the status information indicates whether a defect in the drive energy store is imminent and, in block 220, comprises a setting to a reduced value of a maximum charging voltage and/or of a maximum state of charge for a charging process of the drive energy store by means of a recovery mechanism and/or by means of load point displacement and/or by means of an external charging station, if the status information indicates that a defect is imminent.

[0053] The method 200 can be implemented by means of software, which runs on a processor. In particular, a storage medium containing a software program can be provided, which is designed to run on a processor, thus executing the method described in the present document.

[0054] For example, an “emergency battery operation” bit can be provided which, for example, is permanently engaged with effect from the first positive diagnosis by the spontaneous discharge diagnostic function. A reset of the emergency battery operation bit, for example, can (only) be executed by a (cell) module replacement.

[0055] The emergency battery operation bit triggers the reduction of the maximum charging voltage, in the event of recovery and plug-in charging, such that the maximum SoC can no longer be exceeded, once it has been undershot initially. In some forms of embodiment, the emergency battery operation bit triggers the reduction of the maximum charging power, during recovery, such that no further charging power is released over and above the reduced maximum SoC.

[0056] Provided that the current SoC or the current voltage, further to the engagement of emergency battery operation, remains above the reduced limiting value, no fault will occur accordingly, and the vehicle will remain drivable. Immediately the current SoC or the current voltage, further to the engagement of emergency battery operation, undershoots the reduced limiting value, the latter will no longer be exceeded, either by charging or by recovery.

[0057] Further to the engagement of emergency battery operation, the vehicle can be charged up to the reduced maximum SoC. Any attempted charging to a SoC which exceeds the reduced maximum SoC can be terminated with no resulting fault, or will not be initiated. Charging power can be reduced, in relation to the normal state.

[0058] According to the invention, reduced values are employed for the maximum charging voltage and/or the SoC, if it is established that a cell defect is impending. A preventative measure is thus executed in the event of a detected risk of a cell defect, which minimizes the risk of a direct defect. The vehicle can continue to operate, without the risk of a direct defect. Availability for the customer is increased, and customer satisfaction is enhanced. Moreover, battery fires associated with the direct cell defect can be prevented.