Hybrid chemical vehicle battery cycle life management

Abstract

Hybrid chemical vehicle battery cycle life management is provided. A method for cycle life management of a hybrid chemical battery configured to power a traction motor of a vehicle. The method may include determining a drive load request made for the purpose of requesting the hybrid chemical battery pack to provide a requested amount of electrical power to the traction motor for driving the vehicle; and disconnecting the drive load request to a battery request adapted to provide the requested amount of electrical power from the hybrid chemical battery pack while managing cycle life of the hybrid chemical battery pack independently of the drive load request.

Description

Technical Field

[0001] The present disclosure relates to hybrid chemistry battery packs, such as, but not necessarily limited to, hybrid chemistry vehicle battery packs configured to power a traction motor of a vehicle. Background Art

[0002] A variety of rechargeable energy storage systems (RESS) may be used to power traction motors or other devices operable to convert electrical power into mechanical power for the purpose of propulsion, drive, work, or otherwise operating a vehicle. Cycle life or cycle life values, such as C-ratios, may be used as an indication of the frequency and / or severity with which a RESS may be repeatedly charged and / or discharged. When used, as its cycle life increases, a RESS may experience degradation, reduced efficiency, slower performance, reduced capacity, and other types of potentially performance-limiting effects. Summary of the invention

[0003] One non-limiting aspect of the present disclosure relates to managing the cycle life of a rechargeable energy storage system (RESS), such as, but not necessarily, for the purpose of minimizing degradation, reduced efficiency, slower power delivery, reduced capacity, and other types of potential performance limiting effects resulting from repeated use. The contemplated cycle life management may benefit a wide variety of RESSs, and in particular, may benefit hybrid chemistry battery packs for storing and supplying electrical power to traction motors or other devices operable to propel, drive, work, or otherwise operate a vehicle. A hybrid chemistry battery pack may correspond to a battery pack having a plurality of subpacks, wherein one or more subpacks have different configurations, capabilities, chemical configurations, etc., compared to other subpacks. For example, a type of subpack may perform an electrochemical reaction suitable for supplying and / or storing electrical power at different maximum power levels, consistent power levels, etc., e.g., one subpack may be configured to provide a smaller maximum power than another subpack, but with a longer consistent power.

[0004] One non-limiting aspect of the present disclosure relates to a method for cycle life management of a hybrid chemistry battery pack configured to power a traction motor of a vehicle. The method may include: determining a drive load request made to request the hybrid chemistry battery pack to provide a requested amount of electrical power to the traction motor for the purpose of driving the vehicle; and generating a battery request suitable for providing the requested amount of electrical power from the hybrid chemistry battery pack while managing the cycle life of the hybrid chemistry battery pack independently of the drive load request.

[0005] The battery request may be operable to maximize cycle life by charging and discharging the propulsion subgroup in preference to the energy subgroup.

[0006] The method may include: determining a state of charge (SOC) threshold of a propulsion subgroup; and determining a nominal current limit and a maximum current limit of an energy subgroup, the energy subgroup being configured to provide a smaller maximum power than the propulsion subgroup and a longer consistent power than the propulsion subgroup. The battery request may be operable to: control the propulsion subgroup to supply electric power during a first power stage occurring before the SOC of the propulsion subgroup reaches an upper limit of an SOC threshold to meet the requested amount of electric power without electric power assistance from the energy subgroup; control the energy subgroup to provide an auxiliary amount of electric power to supplement the propulsion subgroup during a second power stage occurring after the SOC reaches an upper limit and before a lower limit of the SOC threshold is exceeded during the first power stage to meet the requested amount of electric power without exceeding the nominal current limit; and control the energy subgroup to provide an auxiliary amount according to a relaxed current limit during a third power stage occurring after the SOC reaches a lower limit and before the SOC exceeds the upper limit during the second power stage, the relaxed current limit being greater than the nominal current and equal to or less than the maximum current limit.

[0007] The battery request may be further operable to control the energy subgroup to provide an amount of assistance without exceeding a nominal current limit during a fourth power phase occurring after the SOC reaches an upper limit during the third power phase.

[0008] The method may include adjusting the relaxed current limit during the third power phase in proportion to an increase in SOC from a lower limit to an upper limit.

[0009] The method may include adjusting the relaxed current limit at a predetermined rate as the SOC increases from a lower limit to an upper limit during a third power stage.

[0010] The method may include determining a charging load request made to request the energy subgroup to provide a charging amount of electrical power to the propulsion subgroup for the purpose of charging the propulsion subgroup; and generating a charging request operable to control the energy subgroup to provide a charging amount of electrical power to the propulsion subgroup.

[0011] The method may include determining a charging load request in response to the vehicle being stationary for a predefined period of time, the SOC being at or below a lower limit, and DC fast charging of the propulsion subgroup being unavailable.

[0012] The charge request may be operable to control the energy subgroup to provide electrical power for a charge amount without exceeding a nominal charge limit.

[0013] The charge request may be operable to control the energy subgroup to provide a charge amount of electrical power at a selectable rate.

[0014] The method may include determining a warming load request made to request the energy subgroup to provide a warming amount of electrical power to the propulsion subgroup for the purpose of warming the propulsion subgroup and generating a warming request operable to control the energy subgroup to provide a warming amount of electrical power to the propulsion subgroup.

[0015] The method may include determining a warming load request in response to the vehicle being stationary for a predefined period of time when DC fast charging of the propulsion subgroup is not available.

[0016] The battery request may be operable to control a converter of the hybrid chemistry battery pack to control the transfer of electrical power between the propulsion subpack and the energy subpack.

[0017] The converter may be a direct current (DC) to DC converter connected in parallel between the propulsion subpack and the energy subpack.

[0018] One non-limiting aspect of the present disclosure relates to a cycle life managed hybrid chemistry battery pack configured to power a traction motor of a vehicle. The battery pack may include a propulsion subgroup, an energy subgroup, a converter configured to control the transmission of electric power from the energy subgroup to the propulsion subgroup, and a controller. The controller may be configured to: determine a drive load request made to request the hybrid chemistry battery pack to provide a requested amount of electric power to the traction motor for the purpose of driving the vehicle; and generate a battery request suitable for providing the requested amount of electric power from the hybrid chemistry battery pack while managing the cycle life of the hybrid chemistry battery pack independently of the drive load request.

[0019] The controller may be configured to maximize cycle life by minimizing charging and discharging of the energy subsets relative to the energy subsets.

[0020] The controller may be configured to determine a state of charge (SOC) threshold for the propulsion subgroup and to determine a nominal current limit and a maximum current limit for an energy subgroup configured to provide less maximum power and longer consistent power than the propulsion subgroup.

[0021] The battery request may be operable to: control the propulsion subgroup to supply electric power to meet the requested amount of electric power without electric power assistance from the energy subgroup during a first power stage occurring before the SOC of the propulsion subgroup reaches an upper limit of an SOC threshold; control the energy subgroup to provide an auxiliary amount of electric power to supplement the propulsion subgroup during a second power stage occurring after the SOC reaches an upper limit and before exceeding a lower limit of the SOC threshold during the first power stage to meet the requested amount of electric power without exceeding a nominal current limit; and control the energy subgroup to provide an auxiliary amount according to a relaxed current limit during a third power stage occurring after the SOC reaches a lower limit and before the SOC exceeds an upper limit during the second power stage, the relaxed current limit being greater than the nominal current and equal to or less than the maximum current limit.

[0022] The battery request may be operable to control the energy subgroup to provide an amount of assistance without exceeding a nominal current limit during a fourth power phase occurring after the SOC reaches an upper limit during the third power phase.

[0023] One non-limiting aspect of the present disclosure relates to a cycle life managed electric power system for powering a traction motor of a vehicle. The system may include a hybrid chemistry battery pack having a propulsion subgroup, an energy subgroup, and a converter configured to control the transfer of electric power from the energy subgroup to the propulsion subgroup. The system may also include a controller configured to: determine a drive load request made to request the hybrid chemistry battery pack to provide a requested amount of electric power to the traction motor for the purpose of driving the vehicle; and generate a battery request in response to the drive load request, the battery request being suitable for providing the requested amount of electric power from the hybrid chemistry battery pack while managing the cycle life of the hybrid chemistry battery pack.

[0024] The controller may be configured to: determine a state of charge (SOC) threshold of the propulsion subgroup; and determine a nominal current limit and a maximum current limit of the energy subgroup, the energy subgroup being configured to provide a smaller maximum power than the propulsion subgroup and a longer consistent power than the propulsion subgroup. The battery request may be operable to: control the propulsion subgroup to supply electric power during a first power stage occurring before the SOC of the propulsion subgroup reaches an upper limit of the SOC threshold to meet the requested amount of electric power without electric power assistance from the energy subgroup; control the energy subgroup to provide an auxiliary amount of electric power to supplement the propulsion subgroup during a second power stage occurring after the SOC reaches an upper limit and before exceeding a lower limit of the SOC threshold in the first power stage to meet the requested amount of electric power without exceeding the nominal current limit; control the energy subgroup to provide an auxiliary amount according to a relaxed current limit during a third power stage occurring after the SOC reaches a lower limit and before the SOC exceeds an upper limit in the second power stage; and control the energy subgroup to provide an auxiliary amount without exceeding the nominal current limit during a fourth power stage occurring after the SOC reaches an upper limit in the third power stage.

[0025] The present disclosure provides the following solutions:

[0026] 1. A method for cycle life management of a hybrid chemistry battery pack, the hybrid chemistry battery pack being configured to power a traction motor of a vehicle, the hybrid chemistry battery pack comprising an energy subpack connected in parallel with a propulsion subpack, the method comprising:

[0027] determining a propulsion load request made to request the hybrid chemistry battery pack to provide a requested amount of electrical power to a traction motor for the purpose of propulsing the vehicle; and

[0028] A battery request is generated in response to the drive load request, the battery request being adapted to provide the requested amount of electrical power from the mixed chemistry battery pack while managing a cycle life of the mixed chemistry battery pack independently of the drive load request.

[0029] 2. The method according to claim 1, wherein:

[0030] The battery request is operable to maximize cycle life by charging and discharging the propulsion subgroup in priority over the energy subgroup.

[0031] 3. The method according to claim 1, further comprising:

[0032] determining a state of charge (SOC) threshold of a propulsion subgroup;

[0033] determining a nominal current limit and a maximum current limit of an energy subgroup, the energy subgroup being configured to provide less maximum power than the propulsion subgroup and more consistent power than the propulsion subgroup;

[0034] Battery requests are operable to:

[0035] controlling the propulsion subgroup to supply electric power to meet the requested amount of electric power without electric power assistance from the energy subgroup during a first power stage occurring before the SOC of the propulsion subgroup reaches an upper limit of the SOC threshold;

[0036] controlling the energy subgroup to provide an assist amount of electric power to supplement the propulsion subgroup during a second power phase occurring after the SOC reaches an upper limit in the first power phase and before a lower limit of the SOC threshold is exceeded to meet the requested amount of electric power without exceeding the nominal current limit; and

[0037] The energy subgroup is controlled to provide an assist amount according to a relaxed current limit during a third power stage occurring after the SOC reaches a lower limit and before the SOC exceeds an upper limit during the second power stage, the relaxed current limit being greater than the nominal current and equal to or less than the maximum current limit.

[0038] 4. The method according to claim 3 further comprises:

[0039] The battery request is operable to control the energy subgroup to provide an amount of assistance without exceeding the nominal current limit during a fourth power phase occurring after the SOC reaches an upper limit during the third power phase.

[0040] 5. The method according to scheme 4 further includes:

[0041] The relaxed current limit is adjusted during the third power stage in proportion to the SOC increasing from the lower limit to the upper limit.

[0042] 6. The method according to claim 4 further comprises:

[0043] During the third power stage, the relaxed current limit is adjusted at a predetermined rate as the SOC increases from the lower limit to the upper limit.

[0044] 7. The method according to claim 3 further comprises:

[0045] determining a charging load request made to request the energy subgroup to provide a charging amount of electrical power to the propulsion subgroup for the purpose of charging the propulsion subgroup; and

[0046] A charge request is generated that is operable to control the energy subgroup to provide a charge amount of electrical power to the propulsion subgroup.

[0047] 8. The method according to claim 7, further comprising:

[0048] A charging load request is determined in response to the vehicle being stationary for a predefined period of time, the SOC being at or below a lower limit, and DC fast charging of the propulsion subgroup being unavailable.

[0049] 9. The method according to claim 7, wherein:

[0050] The charge request is operable to control the energy subgroup to provide electrical power for a charge amount without exceeding a nominal charge limit.

[0051] 10. The method according to claim 7, wherein:

[0052] The charge request is operable to control the energy subgroup to provide a charge amount of electrical power at a selectable rate.

[0053] 11. The method according to claim 1, further comprising:

[0054] determining a warming load request made to request the energy subgroup to provide a warming amount of electrical power to the propulsion subgroup for the purpose of warming the propulsion subgroup; and

[0055] A warming request is generated that is operable to control the energy subgroup to provide a warming amount of electrical power to the propulsion subgroup.

[0056] 12. The method according to claim 11, further comprising:

[0057] The warming load request is determined in response to the vehicle being stationary for a predefined period of time when DC fast charging of the propulsion subgroup is not available.

[0058] 13. The method according to claim 1 further comprises:

[0059] The battery request is operable to control a converter of the hybrid chemistry battery pack to control the transfer of electrical power between the propulsion subpack and the energy subpack.

[0060] 14. The method according to claim 13, wherein:

[0061] The converter is a direct current (DC) to DC converter connected in parallel between the propulsion subpack and the energy subpack.

[0062] 15. A cycle-life managed hybrid chemistry battery pack configured to power a traction motor of a vehicle, the cycle-life managed hybrid chemistry battery pack comprising:

[0063] Advancement subgroup;

[0064] Energy subgroup;

[0065] a converter configured to control the transfer of electrical energy from the energy subgroup to the propulsion subgroup; and

[0066] A controller configured to:

[0067] determining a propulsion load request made to request the hybrid chemistry battery pack to provide a requested amount of electrical power to a traction motor for the purpose of propulsing the vehicle; and

[0068] A battery request is generated in response to the drive load request, the battery request being adapted to provide the requested amount of electrical power from the mixed chemistry battery pack while managing a cycle life of the mixed chemistry battery pack independently of the drive load request.

[0069] 16. The cycle life managed hybrid chemistry battery pack of claim 15, wherein:

[0070] The controller is configured to maximize cycle life by minimizing charging and discharging of the energy subsets relative to the energy subsets.

[0071] 17. The cycle life managed hybrid chemistry battery pack of claim 15, wherein:

[0072] The controller is configured to:

[0073] determining a state of charge (SOC) threshold for the propulsion subgroup; and

[0074] determining a nominal current limit and a maximum current limit for an energy subgroup, the energy subgroup being configured to provide less maximum power than the propulsion subgroup and more consistent power than the propulsion subgroup; and

[0075] Battery requests are operable to:

[0076] controlling the propulsion subgroup to supply electric power to meet the requested amount of electric power without electric power assistance from the energy subgroup during a first power stage occurring before the SOC of the propulsion subgroup reaches an upper limit of the SOC threshold;

[0077] controlling the energy subgroup to provide an assist amount of electric power to supplement the propulsion subgroup during a second power phase occurring after the SOC reaches an upper limit in the first power phase and before a lower limit of the SOC threshold is exceeded to meet the requested amount of electric power without exceeding the nominal current limit; and

[0078] The energy subgroup is controlled to provide an assist amount according to a relaxed current limit during a third power stage occurring after the SOC reaches a lower limit and before the SOC exceeds an upper limit during the second power stage, the relaxed current limit being greater than the nominal current and equal to or less than the maximum current limit.

[0079] 18. The cycle life managed hybrid chemistry battery pack of claim 17, wherein:

[0080] The battery request is operable to control the energy subgroup to provide an amount of assistance without exceeding the nominal current limit during a fourth power phase occurring after the SOC reaches an upper limit during the third power phase.

[0081] 19. A cycle life managed electric power system for powering a traction motor of a vehicle, comprising:

[0082] a hybrid chemistry battery pack having a propulsion subpack, an energy subpack, and a converter configured to control the transfer of electrical power from the energy subpack to the propulsion subpack; and

[0083] A controller configured to:

[0084] determining a propulsion load request made to request the hybrid chemistry battery pack to provide a requested amount of electrical power to a traction motor for the purpose of propulsing the vehicle; and

[0085] A battery request is generated in response to the drive load request, the battery request being adapted to provide the requested amount of electrical power from the hybrid chemistry battery pack while managing a cycle life of the hybrid chemistry battery pack.

[0086] 20. The cycle life managed electric power system of claim 19, wherein:

[0087] The controller is configured to:

[0088] determining a state of charge (SOC) threshold for the propulsion subgroup; and

[0089] determining a nominal current limit and a maximum current limit for an energy subgroup, the energy subgroup being configured to provide less maximum power than the propulsion subgroup and more consistent power than the propulsion subgroup; and

[0090] Battery requests are operable to:

[0091] controlling the propulsion subgroup to supply electric power to meet the requested amount of electric power without electric power assistance from the energy subgroup during a first power stage occurring before the SOC of the propulsion subgroup reaches an upper limit of the SOC threshold;

[0092] controlling the energy subgroup to provide an assist amount of electric power to supplement the propulsion subgroup during a second power phase occurring after the SOC reaches an upper limit and before a lower limit of the SOC threshold is exceeded during the first power phase to meet the requested amount of electric power without exceeding a nominal current limit;

[0093] Controlling the energy subgroup to provide an assist amount according to a relaxed current limit during a third power stage occurring after the SOC reaches a lower limit and before the SOC exceeds an upper limit during the second power stage, the relaxed current limit being greater than the nominal current and equal to or less than the maximum current limit; and

[0094] The energy subgroup is controlled to provide an assist amount without exceeding a nominal current limit during a fourth power phase occurring after the SOC reaches an upper limit during the third power phase.

[0095] When combined with the accompanying drawings, these features and advantages, together with other features and advantages of the present teaching, may be readily apparent from the following detailed description of the mode for carrying out the present teaching. It should be understood that, although the following drawings and embodiments may be described separately, their individual features may be combined into additional embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0096] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate implementations of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0097] Figure 1 A schematic view of a vehicle according to one non-limiting aspect of the present disclosure is shown.

[0098] Figure 2 A schematic diagram of a mixed chemistry battery according to one non-limiting aspect of the present disclosure is shown.

[0099] Figure 3 A flow chart of a method for cycle life according to one non-limiting aspect of the present disclosure is shown.

[0100] Figure 4 A power graph associated with generating a battery request in accordance with one non-limiting aspect of the present disclosure is shown. DETAILED DESCRIPTION

[0101] As needed, detailed embodiments of the present disclosure may be disclosed herein; however, it is understood that the disclosed embodiments may be merely examples of the present disclosure, which may be embodied in various forms and alternative forms. The drawings may not necessarily be to scale; some features may be enlarged or reduced to show details of particular components. Therefore, the specific structural and functional details disclosed herein may not be interpreted as limiting, but merely as a representative basis for teaching those skilled in the art to adopt the present disclosure in different ways.

[0102] Figure 1A schematic view of a vehicle 10 according to one non-limiting aspect of the present disclosure is shown. The vehicle 10 may be configured with a propulsion system, powertrain, or other drivetrain 12 having an electric motor 14 or other electric drive device operable to propel or otherwise drive the vehicle 10. The vehicle 10 is shown as a hybrid type because the powertrain 12 optionally includes an internal combustion engine (ICE) 16. The ICE 16 and the electric motor 14 or other device configured to convert electrical power into mechanical power may cooperate to provide mechanical force / torque to the powertrain 12 for transmission to one or more of a plurality of wheels 20, 22, 24, 26. The powertrain 12 may include a transmission 34, a drive shaft 36, a differential 38, axles 40, 42, and / or other components to facilitate the transmission of rotational force from the ICE 16 and / or the electric motor 14 to the wheels 20, 22, 24, 26. The vehicle 10 is shown to include a powertrain 12 operable with front wheels 20, 24 for non-limiting purposes, as the present disclosure fully contemplates its use and application in four-wheel drive vehicles and other non-automotive types of vehicles. The controller 44 may be configured to generate control signals associated with directing and otherwise achieving desired control of the powertrain 12, the motor 14, the ICE 16, and / or other features of the vehicle 10, for example, the controller 44 may include non-transitory instructions stored on an associated computer-readable storage medium, which, when executed with one or more processors, may be operable to facilitate the operations, processes, controls, etc. described herein.

[0103] The vehicle 10 represents a wide variety of vehicles and / or other devices that may rely on converting electrical power into mechanical power. Such vehicles may be collectively referred to as electric vehicles and include a wide variety of capabilities for supporting the conversion of electrical power into mechanical power, including electric vehicles of a type that can operate without the assistance of the ICE 16. The vehicle 10 is contemplated to include different configurations for generating, storing, and supplying electrical power to the motor 14 and / or other devices or systems onboard and offboard the vehicle 10. The present disclosure contemplates providing some or all of the electrical power based at least in part on the electrical power obtained from a rechargeable energy storage system (RESS) 46. The controller 44 may be configured to manage the operation of the RESS 46 so as to optimize its cycle life, such as by managing its charging and discharging to minimize degradation, reduced efficiency, slower power delivery, reduced capacity, and other types of potential performance limiting effects that may be caused by repeated use. Although the present disclosure fully contemplates its use and application with a wide variety of RESS, the RESS 46 is described primarily with respect to being configured as a hybrid chemical battery pack 46.

[0104] Figure 2A schematic view of a hybrid chemical battery pack 46 according to one non-limiting aspect of the present disclosure is shown. The hybrid chemical battery pack 46 may be included as part of a control architecture associated with exchanging electric power with the motor 14 and / or other devices in communication with the vehicle 10. As can be appreciated by those skilled in the art, in addition to the description of the vehicle 10 provided herein, the hybrid chemical battery pack 46 and its described management can be beneficial to a variety of applications, devices, vehicles, etc. The hybrid chemical battery pack 46 can be configured to facilitate the storage and supply of electric power at least partially relying on electrochemical reactions. The hybrid chemical battery pack 46 can be considered hybrid to the extent that it includes multiple subgroups 50, 52, each of which is configured to perform an electrochemical reaction suitable for storing and supplying electric power. Although the present disclosure fully contemplates the use of more subgroups 50, 52, the hybrid chemical battery pack 46 is shown as including a first subgroup 50 and a second subgroup 52. The first subgroup 50 can be referred to as an energy subgroup 50, and the second subgroup 52 can be referred to as a propulsion subgroup 52.

[0105] To facilitate managing the cycle life of the hybrid chemical battery pack 46, the energy and propulsion subgroups 50, 52 may have different configurations, capabilities, chemical configurations, etc., for performing electrochemical reactions associated with supplying and / or storing electrical power. The relevant differences between the subgroups 50, 52 may be selectively determined and utilized to facilitate managing the cycle life of the hybrid chemical battery pack 46 as a whole. For example, the subgroups 50, 52 may be configured to support different maximum power levels, consistent power levels, etc., for example, the energy subgroup 50 may be configured to provide a smaller maximum power than the propulsion subgroup 52, but have a longer consistent power than the propulsion subgroup 52. The energy subgroup 50 may have a smaller maximum power than the propulsion subgroup 52 but more energy, so that the smaller propulsion subgroup 52 can be used for fast and high-demand power requests, which in turn can help extend the larger energy subgroup 50. The cycle life management contemplated herein can utilize the different characteristics of the subgroups 50, 52 to facilitate long-term maximization and operation of the hybrid chemical battery pack 46, such as by charging and discharging the propulsion subgroup 52 in priority over the energy subgroup 50. The ability to individually control the charging and discharging of the subsets 50, 52, optionally on a different or non-uniform basis, can be beneficial in selectively managing their use according to conditions best suited to improving cycle life.

[0106] The present disclosure contemplates improving the cycle life of the hybrid chemical battery pack 46 by selectively and independently managing the discharge and charging of the energy and propulsion subgroups 50, 52, for example in a manner that exploits their different operating characteristics while also improving the cycle life. For example, this can be achieved by dividing the use of the subgroups 50, 52 to meet the requested power demand in a manner that allows the capabilities of each subgroup to be used for the purpose of improving the overall cycle life of the hybrid chemical battery pack 46, for example, preferentially using the propulsion subgroup 52 over the energy subgroup 50, and vice versa. The hybrid chemical battery pack 46 is shown with the energy subgroup 50 connected in parallel with the propulsion subgroup 52, and a converter 56 therebetween to adjust the current flow. For example, the converter 56 can be configured as a direct current (DC) to DC converter 56, such as a buck-boost converter 56, a switch, or other circuit configurations operable to manage the current flow from the energy subgroup 50 to the propulsion subgroup 52 and / or from the propulsion subgroup 52 to the energy subgroup 50. The converter 56 may be configured to control the power flow between the energy and propulsion subgroups 50, 52 according to commands received from the controller 44 and / or a motor power controller (MPC) 58. The MPC 58 may be included as part of the controller 44 and / or as a separate unit configured to operate the hybrid chemistry battery pack 46 according to the management contemplated herein.

[0107] The commands generated by the MPC 58 to control the hybrid chemistry battery pack 46 (or more specifically, the converter 56, the energy sub-pack 50, and / or the propulsion sub-pack 52) may be generated in a variety of forms, including as signals, such as pulse modulation (PWM) signals, operable to selectively open and close included switches or other circuits and components (not shown). The MPC 58 and / or the hybrid chemistry battery pack 46 may include sensors, feedback, and / or other mechanisms (not shown) operable to sense, calculate, predict, and otherwise perform logical operations associated with monitoring operations of the hybrid chemistry battery pack 46, the vehicle 10, etc., for the purposes of facilitating the management contemplated herein. For example, the MPC 58 may be configured to calculate or otherwise determine the state of charge (SOC) of the sub-packs 50, 52, the load request or demand to provide electrical power to and / or from the hybrid chemistry battery pack 46, the current limit of the sub-packs 50, 52, and / or a variety of other variables operable to direct the hybrid chemistry battery pack 46 in accordance with the cycle life management contemplated herein. The controller 44 and / or the MPC 58 may include corresponding non-transitory instructions operable to generate corresponding commands, instructions, or the like.

[0108] Figure 3A flow chart of a method 64 for cycle life management of a hybrid chemistry battery pack 46 according to one non-limiting aspect of the present disclosure is shown. Block 66 relates to a load request process, whereby the MPC 58 may determine a load or other type of request made to request the hybrid chemistry battery pack 46 to provide a requested amount of electrical power to the motor 14 or other features onboard the vehicle 10, which may be referred to as a drive load request when the electrical power is required for driving the vehicle 10. The drive load request may be determined to be made by the MPC 58 directly and / or indirectly via the controller 44, for example, the controller 44 may receive a demand from the driver or another operator (e.g., an autonomous system). Block 68 relates to a battery request process, whereby the MPC 58 may generate a battery request suitable for controlling the hybrid chemistry battery pack 46 to provide the requested amount of electrical power. The battery request process may include disconnecting the drive load request from the battery request so that the battery request may be generated independently. For example, the battery request may include control parameters generated separately from the parameters defined in the drive load request to enable the cycle life to be managed independently of the drive load request. Block 70 involves the powering process whereby the hybrid chemistry battery pack 46 may be controlled to satisfy the drive load request, ie, to provide the requested power according to the parameters described in the battery request.

[0109] Figure 4 A power graph 74 associated with generating a battery request according to one non-limiting aspect of the present disclosure is shown. The graph 74 may include a propulsion graph 76 reflecting the desired operation of the propulsion subgroup 52 and an energy graph 78 reflecting the desired operation of the energy subgroup 50. The graphs 76, 78 are shown for exemplary purposes relative to a horizontal axis 80 marking time and a vertical axis 82 representing the SOC of the propulsion graph 76 and the current discharge of the energy graph 78. The horizontal axis 80 may represent a time period associated with the following situation: for example, when the power supply process of the frame 70 is ongoing, the hybrid chemical battery pack 46 is controlled to provide electrical power during a charging event to attempt to meet the drive load request. The hybrid SOC and current discharge metrics of the vertical axis 82 may be presented to reflect the relative changes in the energy and propulsion subgroups 50, 52 over time when the hybrid chemical battery pack 46 provides electrical power. The battery request can be derived from the propulsion and energy graphs 76, 78 and adjusted throughout the power supply process to facilitate managing the cycle life of the hybrid chemical battery pack 46. The battery request may be generated by the MPC 58 based on the drive load request, but may optionally be generated in an independent manner to enable the electrical power to be divided between the subgroups 50, 52. Based on the selected chemistry, capabilities, etc. of the propulsion and energy subgroups 50, 52 (which may vary), the present disclosure contemplates maximizing cycle life by charging and discharging the propulsion subgroup 52 in preference to the energy subgroup 50.

[0110] To this end, the start of the first power phase 80 may be used to mark the start whereby the propulsion subgroup 52 may be relied upon to fully provide the requested amount of electric power, i.e., to satisfy the drive load request, without simultaneously drawing electric power from the energy subgroup 50. Figure 3 , block 82 relates to a set point process that may be included as part of the first power stage 80. The set point process may include the MPC 58 setting an SOC threshold 86 for the propulsion subgroup 52, and thereafter monitoring the SOC of the propulsion subgroup 52 to determine whether the SOC is approaching the SOC threshold 86, i.e., the SOC of the propulsion subgroup 52 may decrease over time as the propulsion subgroup 52 continues to be used alone to provide the requested amount of electrical power. Figure 4 As shown, the SOC threshold 86 may include an upper limit 88 and a lower limit 90, where the upper limit 88 specifies the SOC value that the propulsion subgroup 52 is expected to reach before the energy subgroup 50 is controlled to provide an auxiliary amount of electric power as a supplement. The SOC threshold 86 and / or the upper limit 88 and the lower limit 90 may be selectable depending on the desired operating conditions, current environmental influences, vehicle performance strategies, and a number of other variables that may be varied and / or adjusted in real time to meet other operating expectations.

[0111] The second power stage 94 may correspond to controlling the energy subgroup 50 to provide an assist amount of electric power to supplement the propulsion subgroup 52 to meet the requested amount of electric power, which may occur if the energy subgroup 50 provides an assist amount of electric power without exceeding the nominal current limit 96. Figure 3 , box 98 may involve a current control process whereby the MPC 58 determines a nominal current for the energy subgroup 50. The nominal current 96 may correspond to a predefined amount of current provided from the energy subgroup 50 during the second power stage 94, i.e., after the SOC of the propulsion subgroup 52 reaches the upper limit 88 and before the SOC reaches the lower limit 90. The current control process may determine the nominal current 96 based on design parameters, current operating conditions, a state of health (SOH), and / or based on other design parameters. Box 100 involves a monitoring process whereby the MPC 58 may monitor the SOC of the propulsion subgroup 52 to determine whether the auxiliary amount of electric power provided at the nominal current 96 has caused the SOC to approach or exceed one of the upper limit 88 and the lower limit 90. Box 102 involves a current regulation process whereby the MPC 58 may start a third power stage 104 when the SOC reaches the lower limit 90 and before the SOC exceeds the upper limit 88. The current regulation process may include allowing the energy subgroup 50 to initially operate according to the maximum current 106 in box 102 when the SOC reaches the lower limit 88, and thereafter allowing the energy subgroup 50 to operate according to the smaller relaxed current 108 in box 110 as the SOC increases. Like the nominal current 96, the maximum current 106 and the relaxed current 108 may be design parameters selected based on a variety of operational considerations, including a desired upper range or limit on the energy subgroup 50 to manage cycle life.

[0112] Back to Figure 4 , the third power stage 104 may correspond to changing the current limit on the energy subgroup 50 from the nominal current 96 to the maximum current 106, and thereafter decaying from the maximum current 106 to the relaxed current 108 until the SOC reaches the upper limit 88. The third power stage 104 may occur when the auxiliary power provided according to the nominal current 96 during the second power stage 94 causes the SOC to continue to decrease and approach the lower limit 90. During the third power stage 104, the power output of the energy subgroup 50 may correspondingly increase in proportion to the difference between the nominal current 96 and the maximum current 106, and thereafter according to the relaxed current 108, which in turn may relieve some of the power supply burden placed on the propulsion subgroup 52. The SOC of the propulsion subgroup 52 may increase in response to the increased auxiliary power provided by the energy subgroup 50, such that as the SOC increases and approaches the upper limit 88, the relaxed current 108 may decrease proportionally. When the SOC reaches the upper limit 88, the fourth power stage 114 may begin, whereupon the minimum current 96 may return to metering the auxiliary power provided from the energy subgroup 50.

[0113] Back to Figure 3 , block 116 involves controlling the energy subgroup 50 to provide an auxiliary amount of electric power without exceeding the nominal current 96. In the event that the SOC continues to increase above the upper limit 88, the nominal current 96 may optionally be adjusted and / or auxiliary use of the energy subgroup 50 may be stopped. In the event that demand increases or other circumstances occur that cause the SOC to continue to decrease toward the lower limit 90, the above process may be repeated, for example, the energy subgroup 50 may be brought in to provide auxiliary power to supplement the propulsion energy subgroup 50, i.e., to provide auxiliary power in accordance with the minimum, relaxed and / or maximum currents 96, 106, 108. Although the foregoing methods for cycle life management may be primarily based on utilizing the energy subgroup 50 to provide auxiliary electric power to supplement the electric power provided from the propulsion subgroup 52 (which may require corresponding control of the converter 56), the present disclosure fully contemplates other methods for dividing the energy supply between the energy and propulsion subgroups 52.

[0114] As described above, one aspect of the present disclosure relates to a hybrid chemistry battery pack connected in parallel, wherein the "propulsion" battery cell / subpack is directly connected to the load, while the "energy" battery cell / subpack is connected to the load through a DC-DC converter. This creates an opportunity to "disconnect" the load of the energy battery cell from the road load request, and thereby supports a method of reducing the load on the energy battery cell so that the cycle life of this battery cell type can be maximized. The energy battery cells used in the hybrid chemistry battery pack can be advanced chemical battery cells (e.g., LMB, silicon anode) with relatively low cycle life. The method provides a way to improve the cycle life of the energy battery cell by reducing its discharge C rate when feasible, such as when the propulsion battery cell can meet the demand. Conceived approaches may include: disconnecting the battery load from the road load so that the discharge current can be maintained at a low level; controlling the discharge of the energy battery cell so that the SOC of the propulsion battery cell can be maintained at a target level at the same time; and allowing the energy battery cell to slowly charge the propulsion battery cell under certain conditions when the vehicle is not in motion.

[0115] In cold ambient conditions, the propulsion battery cells may experience SOC limiting if the battery cell temperature is too low. In this scenario, when the vehicle is not in motion, power from the energy battery cells may be used to maintain the temperature of the propulsion battery cells above a minimum threshold (a user selectable feature). This may include: the MPC determining a warming load request made to request that the energy subgroup provide a warming amount of electrical power to the propulsion subgroup for the purpose of warming the propulsion subgroup; and generating a warming request operable to control the energy subgroup to provide a warming amount of electrical power to the propulsion subgroup. The warming load request may be determined in response to the vehicle being stationary for a predefined period of time when DC fast charging of the propulsion subgroup is not available.

[0116] A variable converter current limiter algorithm is implemented with the MPC to limit the discharge current of the energy battery cell as much as possible while ensuring that the propulsion battery cell remains in a target SOC window. When the vehicle is not in motion, the propulsion battery cell is at a minimum SOC threshold (the vehicle is in range extension mode), and DC fast charging (DCFC) is not present, the propulsion battery cell can be charged using the energy battery cell with a controlled rate (a customer-selectable feature). This may include: the MPC determines a charging load request made to request the energy subgroup to provide a charging amount of electrical power to the propulsion subgroup for the purpose of charging the propulsion subgroup; and generates a charging request that is operable to control the energy subgroup to provide a charging amount of electrical power to the propulsion subgroup. The charging load request may be determined in response to the vehicle being stationary for a predefined period of time, the SOC being at or below a lower limit, and the DC fast charging of the propulsion subgroup being unavailable. The charging request may be operable to control the energy subgroup to provide a charging amount of electrical power without exceeding a nominal charging limit and / or at a selectable rate.

[0117] The terms "comprise", "include" and "have" are inclusive and thus specify the presence of the stated features, steps, operations, elements or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements or components. When possible, the order of steps, processes and operations can be changed, and additional or alternative steps can be adopted. As used in this specification, the term "or" includes any one and all combinations of the associated listed items. The term "any of..." is understood to include any possible combination of the cited items, including "any one" of the cited items. "One", "one", "the", "at least one" and "one or more" are used interchangeably to indicate that at least one item exists. Unless the context clearly indicates otherwise, there may be multiple such items. All values ​​of parameters (such as quantities or conditions), unless clearly or clearly indicated otherwise according to the context (including the attached claims), should be understood to be modified by the term "approximately" in all cases, regardless of whether "approximately" actually appears before the value. The component that is "configured to" perform the specified function is able to perform the specified function without change, rather than just having the potential to perform the specified function after further modification. In other words, the described hardware, when expressly configured to perform the specified functions, is specifically selected, created, implemented, utilized, programmed, and / or designed for the purpose of performing the specified functions.

[0118] Although various embodiments have been described, the description is intended to be exemplary rather than restrictive, and it will be clear to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of the embodiments. Unless specifically limited, any feature of any embodiment may be used in combination with or replace any other feature or element in any other embodiment. Therefore, the embodiments are not limited except according to the attached claims and their equivalents. In addition, various modifications and changes can be made within the scope of the attached claims. Although several modes for implementing many aspects of this teaching have been described in detail, technicians familiar with the fields to which these teachings are related will recognize various alternative aspects for practicing this teaching within the scope of the attached claims. It is intended that all content contained in the above description or shown in the accompanying drawings should be interpreted as illustrative and exemplary alternative embodiments of the entire range, and ordinary technicians will recognize that these alternative embodiments are implied by the included content, structurally and / or functionally equivalent to the included content, or otherwise become clear based on the included content, and are not limited to those embodiments that are explicitly depicted and / or described.

Claims

1. A method for cycle life management of a hybrid chemistry battery pack, the hybrid chemistry battery pack being configured to power a traction motor of a vehicle, the hybrid chemistry battery pack comprising an energy subpack connected in parallel with a propulsion subpack, the method comprising: determining a propulsion load request made to request the hybrid chemistry battery pack to provide a requested amount of electrical power to a traction motor for the purpose of propulsing the vehicle; as well as A battery request is generated in response to the drive load request, the battery request being adapted to provide the requested amount of electrical power from the mixed chemistry battery pack while managing a cycle life of the mixed chemistry battery pack independently of the drive load request.

2. The method according to claim 1, wherein: The battery request is operable to maximize cycle life by charging and discharging the propulsion subgroup in priority over the energy subgroup.

3. The method according to claim 1, further comprising: determining a state of charge (SOC) threshold of a propulsion subgroup; determining a nominal current limit and a maximum current limit of an energy subgroup, the energy subgroup being configured to provide less maximum power than the propulsion subgroup and more consistent power than the propulsion subgroup; Battery requests are operable to: controlling the propulsion subgroup to supply electric power to meet the requested amount of electric power without electric power assistance from the energy subgroup during a first power stage occurring before the SOC of the propulsion subgroup reaches an upper limit of the SOC threshold; controlling the energy subgroup to provide an assist amount of electric power to supplement the propulsion subgroup during a second power phase occurring after the SOC reaches an upper limit and before a lower limit of the SOC threshold is exceeded during the first power phase to meet the requested amount of electric power without exceeding a nominal current limit; as well as The energy subgroup is controlled to provide an assist amount according to a relaxed current limit during a third power stage occurring after the SOC reaches a lower limit and before the SOC exceeds an upper limit during the second power stage, the relaxed current limit being greater than the nominal current and equal to or less than the maximum current limit.

4. The method according to claim 3, further comprising: The battery request is operable to control the energy subgroup to provide an amount of assistance without exceeding the nominal current limit during a fourth power phase occurring after the SOC reaches an upper limit during the third power phase.

5. The method according to claim 4, further comprising: The relaxed current limit is adjusted during the third power stage in proportion to the SOC increasing from the lower limit to the upper limit.

6. The method according to claim 4, further comprising: During the third power stage, the relaxed current limit is adjusted at a predetermined rate as the SOC increases from the lower limit to the upper limit.

7. The method according to claim 3, further comprising: determining a charging load request made to request the energy subgroup to provide a charging amount of electrical power to the propulsion subgroup for the purpose of charging the propulsion subgroup; as well as A charge request is generated that is operable to control the energy subgroup to provide a charge amount of electrical power to the propulsion subgroup.

8. The method according to claim 7, further comprising: A charging load request is determined in response to the vehicle being stationary for a predefined period of time, the SOC being at or below a lower limit, and DC fast charging of the propulsion subgroup being unavailable.

9. The method according to claim 7, wherein: The charge request is operable to control the energy subgroup to provide electrical power for a charge amount without exceeding a nominal charge limit.

10. The method according to claim 7, wherein: The charge request is operable to control the energy subgroup to provide a charge amount of electrical power at a selectable rate.

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