System and method for adjusting battery state of charge parameters

Abstract

The present disclosure relates to systems and methods for adjusting battery state of charge parameters. A hybrid powertrain system includes a traction battery and a controller. The controller is configured to: in response to a current vehicle speed exceeding a first threshold, reduce a parameter indicating a state of charge (SOC) of the traction battery by an offset to cause the traction battery to charge to an increased state of charge value, wherein the offset varies with an amount of predicted distance within which a predicted vehicle speed profile is below a second threshold.

Description

Technical Field

[0001] The present disclosure relates to hybrid electric vehicles and, more particularly, to controls for regulating battery state of charge. Background Art

[0002] A hybrid electric powertrain system includes an engine and an electric motor. The torque (or power) generated by the engine and / or the electric motor can be transferred to the drive wheels through a transmission to propel the vehicle. A traction battery supplies energy to the electric motor. Summary of the invention

[0003] According to one embodiment, a hybrid powertrain system includes a traction battery and a controller configured to reduce a parameter indicative of a state of charge (SOC) of the traction battery by an offset in response to a current vehicle speed exceeding a first threshold to cause the traction battery to charge to an increased SOC value, wherein the offset varies with an amount of predicted distance over which a predicted vehicle speed profile is below a second threshold.

[0004] According to one embodiment of the invention, the offset increases in response to an increase in the amount of the predicted distance.

[0005] According to one embodiment of the invention, the offset decreases in response to a decrease in the amount of the predicted distance.

[0006] According to an embodiment of the invention, the offset is set to zero in response to the current vehicle speed being lower than a first threshold.

[0007] According to an embodiment of the invention, the offset is set to zero in response to the predicted vehicle speed profile completely exceeding the first threshold value.

[0008] According to an embodiment of the present invention, the parameter is a neutral state of charge (NSOC), and the offset is a neutral state of charge adjustment.

[0009] According to an embodiment of the invention, the offset is limited by the slope of a curve based on a predicted vehicle speed.

[0010] According to another embodiment, a method of pre-charging a traction battery includes reducing a parameter indicative of a state of charge (SOC) of the traction battery by an offset in response to a current vehicle speed exceeding a first threshold to cause the traction battery to charge to an increased SOC value, wherein the offset varies with an amount of predicted distance over which a predicted vehicle speed profile is below a second threshold.

[0011] According to an embodiment of the invention, the method comprises: the offset is increased in response to an increase in the amount of the predicted distance.

[0012] According to an embodiment of the invention, the method comprises: the offset amount is reduced in response to the amount of the predicted distance being reduced.

[0013] According to another embodiment, a vehicle includes a traction battery and a controller configured to reduce a parameter indicative of a state of charge (SOC) of the traction battery by an offset in response to a current vehicle speed exceeding a first threshold to cause the traction battery to charge to an increased SOC value, wherein the offset varies with a predicted amount of time during which a predicted vehicle speed profile is below a second threshold.

[0014] According to one embodiment of the present invention, the offset increases in response to an increase in the amount of predicted time.

[0015] According to one embodiment of the invention, the offset decreases in response to a decrease in the amount of predicted time.

[0016] According to an embodiment of the invention, the offset is set to zero in response to the current vehicle speed being lower than a first threshold.

[0017] According to an embodiment of the invention, the offset is set to zero in response to the predicted vehicle speed profile completely exceeding the first threshold value. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic diagram of an example hybrid electric vehicle.

[0019] Figure 2 is a schematic diagram of an example traction battery.

[0020] Figure 3 It is a system diagram of the energy management system.

[0021] Figure 4 is a graph showing a battery state of charge parameter and the actual state of charge of the battery for a time window.

[0022] Figure 5 is a flow chart showing an algorithm for calculating a neutral state of charge adjustment.

[0023] Figure 6 is a graph showing actual vehicle speed and predicted future vehicle speed for a portion of a vehicle drive cycle.

[0024] Figure 7 It is a control diagram used to adjust a parameter indicating the state of charge of a battery. DETAILED DESCRIPTION

[0025] Embodiments of the present disclosure are described herein. However, it will be understood that the disclosed embodiments are merely examples, and other embodiments may take various forms and alternative forms. The drawings need not be drawn to scale; some features may be exaggerated or minimized to show the details of a particular component. Therefore, the specific structural and functional details disclosed herein should not be interpreted as limiting, but merely as a representative basis for teaching those skilled in the art to utilize the embodiments in various forms. As will be understood by those of ordinary skill in the art, the various features shown and described with reference to any of the figures may be combined with the features shown in one or more other figures to produce embodiments that are not explicitly shown or described. The combination of features shown provides representative embodiments for typical applications. However, various combinations and variations of features consistent with the teachings of the present disclosure may be desired for specific applications or implementations.

[0026] Figure 1 A plug-in hybrid electric vehicle (PHEV) 12 is depicted, but the present disclosure is not limited to PHEVs. The vehicle 12 may include one or more motors 14 mechanically connected to a hybrid transmission 16. The motor 14 can operate as a motor or a generator. In addition, the hybrid transmission 16 is mechanically connected to an engine 18. The hybrid transmission 16 is also mechanically connected to a drive shaft 20, which is mechanically connected to wheels 22. The motor 14 can provide propulsion and deceleration capabilities when the engine 18 is turned on or off. The motor 14 also acts as a generator and can provide fuel economy benefits by recovering energy that would normally be lost as heat in a friction braking system. The motor 14 can also reduce vehicle emissions by allowing the engine 18 to operate at a more efficient speed and allowing the hybrid electric vehicle 12 to operate in an electric mode with the engine 18 turned off under certain conditions.

[0027] The traction battery or battery pack 24 stores energy that can be used by the motor 14. The vehicle battery 24 generally provides a high voltage direct current (DC) output. The traction battery 24 is electrically connected to one or more power electronics modules. One or more contactors 42 can isolate the traction battery 24 from other components when open, and connect the traction battery 24 to other components when closed. The power electronics module 26 is also electrically connected to the motor 14 and provides the ability to transfer energy bidirectionally between the traction battery 24 and the motor 14. For example, the traction battery 24 can provide a DC voltage, and the motor 14 can operate using three-phase alternating current (AC) to function. The power electronics module 26 can convert the DC voltage into a three-phase AC current to operate the motor 14. In the regenerative mode, the power electronics module 26 can convert the three-phase AC current from the motor 14 used as a generator into a DC voltage compatible with the traction battery 24.

[0028] The traction battery 24 can provide energy for other vehicle electrical systems in addition to providing energy for propulsion. The vehicle 12 can include a DC / DC converter module 28 that converts the high voltage DC output of the traction battery 24 into a low voltage DC supply that is compatible with low voltage vehicle loads. The output of the DC / DC converter module 28 can be electrically connected to an auxiliary battery 30 (e.g., a 12V battery). The low voltage systems can be electrically connected to the auxiliary battery. Other high voltage loads 46 (such as a compressor and an electric heater) can be connected to the high voltage output of the traction battery 24.

[0029] The vehicle 12 may be a plug-in hybrid vehicle that can recharge the traction battery 24 via an external power source 36. The external power source 36 may be connected to an electrical outlet. The external power source 36 may be electrically connected to a charger or electric vehicle supply equipment (EVSE) 38. The external power source 36 may be a distribution network or grid provided by a public power company. The EVSE 38 may provide circuitry and control to regulate and manage energy transfer between the power source 36 and the vehicle 12. The external power source 36 may provide DC power or AC power to the EVSE 38. The EVSE 38 may have a charging connector 40 for plugging into a charging port 34 of the vehicle 12. The charging port 34 may be any type of port configured to transfer power from the EVSE 38 to the vehicle 12. The charging port 34 may be electrically connected to a charger or an onboard power conversion module 32. The power conversion module 32 may regulate the power supplied from the EVSE 38 to provide a suitable voltage level and current level to the traction battery 24. The power conversion module 32 may interface with the EVSE 38 to coordinate power transfer to the vehicle 12. The EVSE connector 40 may have prongs that closely mate with corresponding recesses of the charging port 34. Alternatively, the various components described as being electrically coupled or electrically connected may transfer power using wireless inductive coupling.

[0030] One or more wheel brakes 44 may be provided to decelerate the vehicle 12 and prevent the vehicle 12 from moving. The wheel brakes 44 may be hydraulically actuated, electrically actuated, or some combination thereof. The wheel brakes 44 may be part of a braking system 50. The braking system 50 may include other components for operating the wheel brakes 44. For simplicity, the accompanying drawings depict a single connection between the braking system 50 and one of the wheel brakes 44. The connection between the braking system 50 and the other wheel brakes 44 is implicit. The braking system 50 may include a controller for monitoring and coordinating the braking system 50. The braking system 50 may monitor the brake components and control the wheel brakes 44 to decelerate the vehicle. The braking system 50 may respond to driver commands and may also operate autonomously to implement functions such as stability control. The controller of the braking system 50 may implement a method for applying the requested braking force when requested by another controller or sub-function.

[0031] One or more electrical loads 46 may be connected to the high voltage bus. The electrical loads 46 may have associated controllers that operate and control the electrical loads 46 as appropriate. An example of an electrical load 46 may be a heating module or an air conditioning module.

[0032] The electronic modules in the vehicle 12 may communicate via one or more vehicle networks. The vehicle network may include multiple channels for communication. One channel of the vehicle network may be a serial bus such as a controller area network (CAN). One of the channels of the vehicle network may include an Ethernet network defined by the Institute of Electrical and Electronics Engineers (IEEE) 802 family of standards. Other channels of the vehicle network may include discrete connections between modules and may include power signals from the auxiliary battery 30. Different signals may be transmitted over different channels of the vehicle network. For example, a video signal may be transmitted over a high-speed channel (e.g., Ethernet) while control signals may be transmitted over CAN or discrete signals. The vehicle network may include any hardware components and software components that assist in transmitting signals and data between modules. Figure 1 The vehicle network is not shown in FIG, but may be implied to be connected to any electronic modules present in the vehicle 12. A vehicle system controller (VSC) 48 may be present to coordinate the operation of the various components.

[0033] Traction battery 24 may be constructed of a variety of chemistries. Typical battery pack chemistries may include: lead acid, nickel-metal hydride (NIMH), or lithium ion. Figure 2 An example traction battery pack 24 is shown of a simple series configuration of N battery cells 72. However, other battery packs may be composed of any number of individual battery cells connected in series, in parallel, or some combination thereof. The battery management system may have one or more controllers (such as a battery energy control module (BECM)) 76 that monitor and control the performance of the traction battery 24. The battery pack 24 may include sensors to measure a variety of battery level characteristics. The battery pack 24 may include one or more battery current measurement sensors 78, battery voltage measurement sensors 80, and battery temperature measurement sensors 82. The BECM 76 may include circuitry for interfacing with the battery current sensor 78, battery voltage sensor 80, and battery temperature sensor 82. The BECM 76 may have non-volatile memory so that data can be saved when the BECM 76 is in a shutdown condition. The saved data may be available at the next key cycle.

[0034] In addition to the battery pack level characteristics, there may also be battery cell 72 level characteristics that are measured and monitored. For example, the terminal voltage, current, and temperature of each battery cell 72 may be measured. The system may use a sensor module 74 to measure the characteristics of the battery cell 72. Depending on the capabilities, the sensor module 74 may measure the characteristics of one or more battery cells 72. The battery pack 24 may utilize up to Nc sensor modules 74 to measure the characteristics of all battery cells 72. Each sensor module 74 may transmit the measurement results to the BECM 76 for further processing and coordination. The sensor module 74 may transmit the signal in analog or digital form to the BECM 76. In some configurations, the functions of the sensor module 74 may be integrated into the BECM 76. That is, the hardware of the sensor module 74 may be integrated as part of the circuit in the BECM 76, and the BECM 76 may be responsible for processing the raw signal. The BECM 76 may also include a circuit connected to one or more contactors 42 interfaces to open and close the phase contactors 42.

[0035] It may be useful to calculate a number of characteristics of the battery pack. Quantities such as the battery power capacity and the battery state of charge (SOC) may be used to control the operation of the traction battery 24 and to control the operation of any electrical loads that receive power from the traction battery. The battery power capacity is a measure of the maximum amount of power that the traction battery can provide or the maximum amount of power that the traction battery can receive. Knowing the battery power capacity allows the electrical loads to be managed so that the power requested is within the limits that the traction battery can handle.

[0036] The battery pack SOC gives an indication of how much charge is left in the battery. The SOC can be expressed as a percentage of the total charge remaining in the battery pack. Similar to a fuel gauge, the battery SOC can be output to inform the driver how much charge is left in the battery. The battery SOC can also be used to control the operation of an electric vehicle or a hybrid electric vehicle. The calculation of the battery SOC can be accomplished in a variety of ways. One possible method of calculating the battery SOC is to perform an integration of the battery current over time. This method is known in the art as ampere-hour integration.

[0037] Refer back to Figure 1 , the vehicle 12 may include a navigation module 52 for providing route planning information to the operator. The navigation module 52 may include a vehicle position sensor compatible with a global positioning system (GPS). The navigation module 52 may include a display for displaying a map and route information. The display may be a touch screen for inputting information to the navigation module 52. The operator may enter a destination or select a destination from storage. The navigation module 52 may output the vehicle position to other modules. The navigation module 52 may also output route information to other modules.

[0038] The vehicle 12 may include a wireless communication module 54 to communicate with devices and systems away from the vehicle 12. The wireless communication module 54 may include an onboard modem with an antenna to communicate with non-onboard devices or systems. The wireless communication module 54 may be a cellular communication device that enables communication via a cellular data network. The wireless communication module 54 may be a wireless local area network (LAN) device compatible with the IEEE802.11 family of standards (i.e., WiFi) or a WiMax network. The wireless communication module 54 may include a vehicle-based wireless router to allow connection to a remote network within the range of a local router. The wireless communication module 54 may be connected to one or more controller interfaces in the vehicle 12 to provide data. For example, the data may include traffic and construction data, route planning instructions, and weather data. The navigation module 52 may use the data received via the wireless communication module 54 to determine the route of the vehicle 12.

[0039] Reference Figure 3 , an energy management system (EMS) 100 may operate the vehicle's powertrain to minimize fuel consumption. The powertrain may include an engine, a transmission, an electric machine and associated power electronics modules, and a traction battery. The EMS 100 may determine the operating state of the engine and the electric machine to minimize the fuel consumption of the engine. The functionality of the EMS 100 may be incorporated into one or more controllers (such as the VSC 48).

[0040] The EMS 100 may receive inputs such as driver requested torque 102, engine speed 104, battery SOC 106, and battery power limit 108. Based on these inputs, the EMS 100 is configured to output an engine on / off command 110 and an energy management torque command 112. The vehicle's powertrain is controlled based on the outputs 110 and 112 and other parameters.

[0041] Reference Figure 4 , the controller 48 may have a basic operating window 120 for the battery SOC. The window 120 includes an upper limit 122, a lower limit 124, and an intermediate state of charge (NSOC) 126. The NSOC 126 may be the median value of the window 120. In the example shown, the upper limit is 60% SOC, the lower limit is 40% SOC, and the NSOC is 50% SOC, but other values ​​may also be considered. The NSOC 126 is a baseline SOC for the battery, but as shown in FIG. Figure 4 As shown, the actual SOC 128 fluctuates above and below the NSOC 126 between an upper limit 122 and a lower limit 124 based on the operating conditions of the vehicle.

[0042] The traction battery 24 may also have a maximum SOC 130 and a minimum SOC 132. An upper operating window 134 is defined between the maximum SOC 130 and the upper limit 122, and a lower operating window 136 is defined between the minimum SOC 132 and the lower limit 124. Under a limited set of conditions, the controller 48 allows the battery SOC to enter the upper and lower operating windows. For example, the controller 48 may allow the battery SOC to enter the lower operating window 136 to start the engine, or enter the upper operating window 134 to pre-charge the traction battery 24.

[0043] In order to increase the electric range of the vehicle 12, the battery 24 may be precharged to a higher SOC when electric propulsion of the vehicle is predicted to be needed in the near future. For example, if a traffic jam is detected ahead of the vehicle, the battery 24 may be precharged. Precharging may be performed when battery charging is effective (e.g., the engine is on and the vehicle is above 30 miles per hour (mph). The battery may be precharged by moving the baseline NSOC 120 to a higher battery SOC to prompt the battery to be charged by the EMS 100. For example, the window 120 may be moved so that the upper limit is 70% SOC, the lower limit is 50% SOC, and the NSOC is 60% SOC. The NSOC of the moved window may be referred to as an adjusted NSOC. The amount of adjustment may be a dynamic value based on the current operating conditions and predicted operating conditions of the vehicle, rather than a predefined value. The above percentages are merely illustrative.

[0044] The control logic or functions performed by the controller 48 may be represented by a flowchart or similar schematic diagram in one or more of the accompanying drawings. These drawings provide representative control strategies and / or logic that can be implemented using one or more processing strategies (such as event-driven, interrupt-driven, multi-tasking, multi-threading, etc.). Therefore, the various steps or functions shown may be performed in the sequence shown, may be performed in parallel, or may be omitted in some cases. Although not always explicitly shown, it will be recognized by those of ordinary skill in the art that one or more of the steps or functions shown may be repeatedly performed according to the specific processing strategy used. Similarly, the order of processing is not necessarily required to achieve the features and advantages described herein, but is provided for ease of illustration and description. The control logic may be implemented primarily in software, which is executed by a microprocessor-based vehicle, engine and / or powertrain controller (such as controller 48). Of course, depending on the specific application, the control logic may also be implemented in software, hardware, or a combination of software and hardware in one or more controllers. When the control logic is implemented in software, the control logic may be provided in one or more computer-readable storage devices or media having stored data, the data representing the code or instructions executed by the computer for controlling the vehicle or its subsystems. The computer-readable storage device or medium may include one or more of a number of known physical devices that utilize electrical, magnetic, and / or optical storage to store executable instructions and associated calibration information, operating variables, and the like.

[0045] Figure 5 1 is a flow chart diagram of an algorithm for regulating the NSOC to pre-charge the traction battery. In operation 152 , the controller 48 defines a predictive moving window 184 for the vehicle 12 . Figure 6A predicted moving window 184 of the vehicle 12 during a hypothetical driving cycle 180 is shown. In this example, the x-axis is distance, but in other embodiments, the x-axis may be time. D0 represents the current vehicle position, and the trajectory 182 shows the actual past speed of the vehicle 12. The moving window 184 is a distance (ΔD), or in other embodiments, the moving window 184 is time, which can accurately predict future vehicle operations (such as speed) ahead of the vehicle. The size of the window 184 may be predefined, or may be based on the amount of available information (such as map data, traffic data, vehicle history data, etc.) at each time. In operation 154, the controller generates a predicted future speed profile 186 of the vehicle 12 for the moving window 184. The speed profile 186 may be calculated using map data, traffic data, speed limit data, vehicle history data, etc. The communication module 54 and the navigation module 52 and other vehicle modules may be used to create the window 184 and the speed profile 186. In operation 156, the controller defines an upper speed threshold (V2) and a lower speed threshold (V1). Vehicle speeds at and above the upper threshold V2 are speeds corresponding to efficient battery charging, and vehicle speeds at and below the lower threshold V1 are speeds corresponding to efficient electric propulsion. The actual values ​​of V1 and V2 will vary depending on the specific design of the hybrid powertrain (such as motor / generator power and battery size), but for illustration purposes, V1 may be 15 mph and V2 may be 30 mph.

[0046] To improve the electric driving range of the vehicle, the battery 24 may be pre-charged based on the predicted distance and / or time that the future speed 186 is above V2 and based on the predicted distance and / or time that the future speed 186 is below V1. The pre-charging of the battery 24 may be achieved by increasing the NSOC to an adjusted NSOC. Adjusting the NSOC to an increased value causes the EMS 100 to charge the battery 24 more frequently and causes the battery 24 to charge to a higher SOC than when the NSOC is at a baseline value. At operations 158 to 166, the amount of adjustment is calculated by the controller 48.

[0047] At operation 158, the controller calculates the cumulative distance (s(t)) and time (T(t)) that the predicted future speed profile 186 for the window 184 is at or below V1 for each time step (t). This represents the distance and time that the vehicle 12 is expected to utilize at least some electric propulsion. At operation 160, the controller 48 calculates the desired battery NSOC adjustment (ΔNSOC(t)) based on the s(t) and T(t) calculated in operation 158. The controller 48 may calculate ΔNSOC(t) using Equation 1, where a, b, and c are calibratable coefficients for accounting for variables such as accessory load, and the ΔNSOC(t) value may increase as S(t) and T(t) increase, and decrease as S(t) and T(t) decrease. If the profile 186 is completely above V1, then ΔNSOC(t) may be set to zero.

[0048] ΔNSOC(t)=a*s(t)+b*T(t)+c (Formula 1)

[0049] The battery 24 may be pre-charged only if the vehicle speed is predicted to be above V2 in window 184 because active battery charging may not be required when the vehicle speed is below V2 due to potentially inefficient operation. In operation 162, the controller 48 determines whether the vehicle speed is predicted to be above V2 in window 184. If the controller 48 determines that the vehicle speed is not predicted to be above V2 in window 184, ΔNSOC(t) is set to zero. If the controller 48 determines that the vehicle speed is predicted to be above V2 in window 184, ΔNSOC(t) of operation 160 is not modified. In operation 162, Equation 2 may be used. Other factors may also be used to adjust ΔNSOC(t). For example, if the road grade exceeds a threshold, ΔNSOC(t) may be set to zero. Other

[0050]

[0051] The battery 24 has a maximum SOC limit and a minimum SOC limit that are set based on the physical constraints of the battery and other components of the high voltage system. The maximum SOC limit and the minimum SOC limit can be predefined values. At operation 164, the controller 48 determines whether adjusting the reference NSOC by ΔNSOC(t) from operation 162 will place the adjusted NSOC outside the maximum SOC limit and the minimum SOC limit. If it is determined that adjusting the reference NSOC by ΔNSOC(t) from operation 162 will not place the adjusted NSOC outside the maximum SOC limit and the minimum SOC limit, the ΔNSOC(t) from operation 162 is passed. If ΔNSOC(t) exceeds the maximum SOC limit, ΔNSOC(t) is reduced so that the adjusted SOC is below the maximum SOC limit.

[0052] In order to provide a smooth transition when adjusting the NSOC, one or more slopes (slew rates) may be used for transitions between the baseline NSOC and the adjusted NSOC and between different adjusted NSOCs. Different slopes can be used for different types of transitions and transitions of different magnitudes. For example, when moving from the baseline NSOC to the adjusted NSOC, a first slope may be used, and when moving from the adjusted NSOC to the baseline NSOC, a second slope may be used. Different slopes may also be used depending on whether the NSOC is increasing or decreasing. Each slope may be a predetermined value stored in one or more lookup tables, or may be a dynamic value that changes based on operating conditions (such as vehicle speed). In operation 166, the controller calculates the slope of each transition within the window 184, and may reduce the ΔNSOC(t) value at each time step to a value set by the slope.

[0053] Equation 3 or Equation 4 can be used to determine the slope. Equation 3 is in the spatial domain, while Equation 4 is in the time domain. Wherein, v(t) is the vehicle speed at time t; k1 is the maximum slope; -k2 is the minimum slope when the vehicle speed is greater than v2; -k3 is the minimum slope when the vehicle speed is between v1 and v2; and -k4 is the minimum slope when the vehicle speed is less than v1.

[0054]

[0055]

[0056] At operation 168 , an NSOC adjustment (ΔNSOC(t)) is output. ΔNSOC(t) may be considered an offset that is used to reduce a parameter indicative of state of charge (SOC), thereby producing an artificially low SOC value. The artificially low SOC value may be output to the EMS 100 to cause the battery to charge.

[0057] Reference Figure 7 The controller calculates the actual state of charge (SOC act )200, the SOC act is fed to the differential element 202. ΔNSOC(t) 204 from operation 168 is also fed to the differential element 202, and from SOC act 200, ΔNSOC(t) 204 is subtracted. The regulated SOC (SOC adj )106, and SOC adj 106 is fed to EMS 100. SOC adj106 has an artificially low magnitude, which causes the EMS 100 to perceive the battery SOC as being lower than its actual value. As a result, the EMS 100 commands the battery to be charged more frequently and to a higher battery SOC than would normally occur under the basic energy management strategy. Figure 3 In response to receiving the artificially low battery SOC input 106, the EMS 100 outputs an increasing energy management torque command 112 to the electric machine over time. This causes the electric machine to output additional power to the battery 24 to pre-charge the battery.

[0058] Although exemplary embodiments are described above, these embodiments are not intended to describe all possible forms covered by the claims. The words used in the specification are descriptive rather than restrictive, and it should be understood that various changes can be made without departing from the spirit and scope of the present disclosure. As previously mentioned, the features of various embodiments can be combined to form further embodiments of the present invention that may not be explicitly described or shown. Although various embodiments may have been described as providing advantages or being superior to other embodiments or prior art implementations for one or more desired characteristics, it should be recognized by those of ordinary skill in the art that one or more features or characteristics can be compromised to achieve the desired overall system properties according to specific applications and implementations. These properties may include, but are not limited to: cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, maintainability, weight, manufacturability, ease of assembly, etc. Therefore, in the case where any embodiment is described as not as satisfactory as other embodiments or prior art implementations in one or more characteristics, these embodiments are not outside the scope of the present disclosure and can be expected to be used for specific applications.

Claims

1. A hybrid powertrain system comprising: Traction batteries; as well as A controller is configured to reduce an actual state of charge value of a traction battery by an offset amount to cause the traction battery to charge to an increased state of charge value in response to a current vehicle speed exceeding a first threshold, wherein the offset amount varies with an amount of predicted distance within which the predicted vehicle speed profile is below a second threshold.

2. The hybrid powertrain system according to claim 1, wherein: The offset also varies with the predicted amount of time during which the predicted vehicle speed profile is below the second threshold.

3. The hybrid powertrain system according to claim 1, wherein: The offset increases in response to an increase in the amount of the predicted distance.

4. The hybrid powertrain system according to claim 1, wherein: The offset decreases in response to the predicted amount of distance decreasing.

5. The hybrid powertrain system according to claim 1, wherein: The offset is set to zero in response to a current vehicle speed being below a first threshold.

6. The hybrid powertrain system according to claim 1, wherein: The offset is set to zero in response to the predicted vehicle speed profile completely exceeding the second threshold.

7. The hybrid powertrain system according to claim 1, wherein: The offset is limited by the slope of the curve based on the predicted vehicle speed.

8. A vehicle comprising: Traction batteries; as well as The controller is configured as; In response to a current vehicle speed exceeding a first threshold, an actual state of charge value of the traction battery is reduced by an offset to cause the traction battery to charge to an increased state of charge value, wherein the offset varies with a predicted amount of time during which the predicted vehicle speed profile is below a second threshold.

9. The vehicle according to claim 8, wherein: The offset is set to zero in response to a current vehicle speed being below a first threshold.

10. The vehicle according to claim 8, wherein: The offset is set to zero in response to the predicted vehicle speed profile completely exceeding the second threshold.

11. The vehicle according to claim 8, wherein: The offset is limited by the slope of the curve based on the predicted vehicle speed.

12. A method for pre-charging a traction battery, comprising: In response to the current vehicle speed exceeding the first threshold, the actual state of charge value of the traction battery is reduced by an offset to cause the traction battery to charge to an increased state of charge value, wherein the offset varies with an amount of predicted distance within which the predicted vehicle speed profile is below a second threshold.

13. The method according to claim 12, wherein: The offset also varies with the predicted amount of time during which the predicted vehicle speed profile is below the second threshold.

14. The method according to claim 12, wherein: The offset amount increases in response to an increase in the amount of the predicted distance, and the offset amount decreases in response to a decrease in the amount of the predicted distance.

15. The method according to claim 12, wherein: The offset is set to zero in response to a current vehicle speed being below a first threshold.

16. The method according to claim 12, wherein: The offset is set to zero in response to the predicted vehicle speed profile completely exceeding the second threshold.

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