Electrical system including multiple battery chemistries and method of operation thereof

Abstract

An electrical system includes a battery pack assembly including a first set of battery cells and a second set of battery cells. The first set of battery cells includes a first battery chemistry and the second set of battery cells includes a second battery chemistry different from the first battery chemistry. The switch selectively connects the first battery cell set and the second battery cell set in series with the battery connection terminal. The DC-DC converter provides dynamic energy distribution between the first and second sets of battery cells. The controller controls the switch and the DC-DC converter. The controller is configured to determine an operating strategy and, in response to the operating strategy of the battery pack assembly, set the first set of battery cells, the second set of battery cells, or both the first set of battery cells and the second set of battery cells in electrical communication with the battery connection terminals.

Description

[0001] Introduction

[0002] This disclosure relates to energy or power storage and transmission, and more particularly to electrical systems including battery pack assemblies having multiple battery chemistries and methods for controlling the operation of such systems.

[0003] Electrified powertrain systems for motor vehicles and other mobile electrical systems include electrical storage and transmission systems configured to supply energy to one or more electric motors to generate motive torque. For example, an electric traction motor can be connected to the wheels of an electric vehicle, where the generated output torque is directed to the wheels to propel the electric vehicle on a road surface.

[0004] A variety of rechargeable energy storage systems (RESS) can be used to power a traction motor or other output device operable to convert electrical energy into mechanical energy for the purpose of propelling, driving, or otherwise operating a vehicle. In use, a RESS may experience degradation, reduced efficiency, slower charge and discharge performance, reduced capacity, and other types of possible performance limiting effects. Systems and methods are desired that can improve the performance of such systems. Summary of the Invention

[0005] An electrical system is provided in accordance with one or more embodiments. The electrical system includes a battery pack assembly. The battery pack assembly includes a first set of battery cells having a first plurality of energy storage battery cells, the first plurality of energy storage battery cells including a first battery chemistry. A second set of battery cells has a second plurality of energy storage battery cells, the second plurality of energy storage battery cells including a second battery chemistry different from the first battery chemistry. One or more switches are configured to selectively connect the first set of battery cells and the second set of battery cells in series with a battery connection terminal for electrical communication therebetween. A DC-DC converter is connected to the first set of battery cells and the second set of battery cells and is configured to provide dynamic energy distribution between the first and second sets of battery cells. The electrical system further includes a controller that controls the one or more switches and the DC-DC converter. The controller is configured to determine an operating strategy for the battery pack assembly. The controller is further configured to, in response to the operating strategy of the battery pack assembly, set the first set of battery cells, the second set of battery cells, or both the first set of battery cells and the second set of battery cells to be in electrical communication with the battery connection terminal.

[0006] In some embodiments, the first battery chemistry includes a high energy density battery chemistry and the second battery chemistry includes a high charge and discharge rate battery chemistry.

[0007] In some embodiments, the high energy density battery chemistry includes a lithium ion battery chemistry, and the lithium ion battery chemistry includes a cathode comprising nickel, cobalt, and manganese (NCM battery chemistry). The high charge and discharge rate battery chemistry includes a sodium ion battery chemistry (sodium battery chemistry).

[0008] In some embodiments, the one or more switches include a first switch and a second switch, the first switch and the second switch are position-controlled by the controller and are configured to be in electrical communication with a first battery cell set and a second battery cell set. The first switch has a first switch A position and a second switch A position, and the second switch has a first switch B position and a second switch B position. When the controller places the first switch in the first switch A position and the second switch in the first switch B position, the first battery cell set is in electrical communication with the battery connection terminal, while the second battery cell set is disconnected from the battery connection terminal. When the controller places the first switch in the first switch A position and the second switch in the second switch B position, the first battery cell set and the second battery cell set are in electrical communication with the battery connection terminal in series. When the controller places the first switch in the second switch A position and the second switch in the second switch B position, the second battery cell set is in electrical communication with the battery connection terminal, while the first battery cell set is disconnected from the battery connection terminal.

[0009] In some embodiments, the first switch further has a switch A off position and the second switch further has a switch B off position. When the controller places the first switch in the switch A off position and the second switch in the switch B off position, the battery pack assembly is disconnected from the battery connection terminal.

[0010] In some embodiments, the one or more switches include a first switch and a second switch, the first switch and the second switch are position-controlled by the controller and are configured to be in electrical communication with a first battery cell set. The first switch has a first switch A position and a second switch A position, and the second switch has a first switch B position and a switch B off position. When the controller places the first switch in the first switch A position and the second switch in the switch B off position, the first battery cell set and the second battery cell set are in electrical communication with the battery connection terminal in series. When the controller places the first switch in the second switch A position and the second switch in the first switch B position, the first battery cell set is connected in parallel with the second battery cell set for electrical communication with the battery connection terminal.

[0011] In some embodiments, the operation strategy includes a relatively high energy state of charge (SOC) charging strategy for direct current fast charging (DCFC) for a situation where the second battery cell set has an SOC at or above a predetermined SOC threshold. The relatively high energy SOC charging strategy includes: performing DCFC on the second battery cell set towards a predetermined SOC threshold approaching full charge, while the DC-DC converter distributes energy to the first battery cell set. If the second battery cell set reaches the predetermined SOC threshold approaching full charge, the first battery cell set performs DCFC towards a full charge SOC, while the DC-DC converter distributes energy to the second battery cell set to charge both the first and second battery cell sets towards the full SOC.

[0012] In some embodiments, the predetermined SOC threshold is from about 25% to about 35%, and the predetermined SOC threshold approaching full charge is from about 94% to about 98%.

[0013] In some embodiments, the operation strategy includes a relatively low energy SOC charging strategy for a situation where the second battery cell set has an SOC at or below a predetermined SOC threshold approaching zero. The relatively low energy SOC charging strategy includes performing DCFC on the second battery cell set towards a predetermined SOC threshold approaching full charge, while the DC-DC converter distributes energy to the first battery cell set. If the second battery cell set reaches the predetermined SOC threshold approaching full charge, the first battery cell set performs DCFC towards a full charge SOC, while the DC-DC converter distributes energy to the second battery cell set to charge both the first battery cell set and the second battery cell set towards the full charge SOC. Alternatively, the first and second battery cell sets are charged towards the full charge SOC simultaneously without DCFC operation.

[0014] In some embodiments, the predetermined SOC threshold approaching zero is from about 0% to about 10%, and the predetermined SOC threshold approaching full charge is from about 94% to about 98%.

[0015] In some embodiments, the operation strategy includes a relatively high SOC discharge strategy for the case where the SOC of the second battery cell set is higher than a predetermined SOC threshold. The relatively high SOC discharge strategy includes discharging the first battery cell set and the second battery cell set while the DC-DC converter distributes the energy from the second battery cell set to the first battery cell set until the second battery cell set is at or below the predetermined SOC threshold. If the second battery cell set is at or below the predetermined SOC threshold, the first and second battery cell sets are discharged while the DC-DC converter distributes the energy from the first battery cell set to the second battery cell set to fully discharge the first and second battery cell sets.

[0016] In some embodiments, the predetermined SOC threshold is from about 25% to about 35%.

[0017] In some embodiments, the operation strategy includes a relatively low temperature discharge strategy for the case where the battery pack assembly is at a predetermined low temperature threshold. The relatively low temperature discharge strategy includes discharging the second battery cell set while the first battery cell set is disconnected from the battery connection terminal and the DC-DC converter distributes the energy to heat the first battery cell set to a temperature higher than the predetermined low temperature threshold. When the battery pack assembly is at or above a temperature higher than the predetermined low temperature threshold, the first and second battery cell sets are discharged simultaneously.

[0018] In some embodiments, the predetermined low temperature threshold is from about -35°C to about -20°C.

[0019] In some embodiments, the operation strategy includes a relatively low DC voltage condition drive cycle discharge strategy, and the relatively low DC voltage condition drive cycle discharge strategy includes: discharging the first battery cell set when the second battery cell set is disconnected from the battery connection terminal; or discharging the second battery cell set when the first battery cell set is disconnected from the battery connection terminal.

[0020] In some embodiments, the operation strategy includes a relatively high DC voltage condition drive cycle discharge strategy, and the relatively high DC voltage condition drive cycle discharge strategy includes discharging the first battery cell set and the second battery cell set.

[0021] A method of operating an electrical system according to one or more embodiments is provided. The method includes determining an operating strategy for a battery pack assembly. The battery pack assembly includes: a first set of battery cells having a first plurality of energy storage battery cells, the first plurality of energy storage battery cells including a first battery chemistry; and a second set of battery cells having a second plurality of energy storage battery cells, the second plurality of energy storage battery cells including a second battery chemistry different from the first battery chemistry. The method further includes: in response to the operating strategy of the battery pack assembly, setting the first set of battery cells, the second set of battery cells, or both the first set of battery cells and the second set of battery cells in series to be in electrical communication with battery connection terminals. Optionally, in response to the operating strategy of the battery pack assembly, providing dynamic energy distribution between the first set of battery cells and the second set of battery cells.

[0022] A vehicle according to one or more embodiments is provided. The vehicle includes an output device and an electrical system. The electrical system is configured to provide electrical energy to the output device. The electrical system includes a battery pack assembly. The battery pack assembly includes: a first set of battery cells having a first plurality of energy storage battery cells, the first plurality of energy storage battery cells including a first battery chemistry; and a second set of battery cells having a second plurality of energy storage battery cells, the second plurality of energy storage battery cells including a second battery chemistry different from the first battery chemistry. One or more switches are configured to selectively connect the first set of battery cells and the second set of battery cells in series with battery connection terminals for electrical communication therebetween. The battery connection terminals are configured to be in electrical communication with the output device to discharge the battery pack assembly and drive the vehicle, and independently in electrical communication with a charger to charge the battery pack assembly. A DC-DC converter is connected to the first set of battery cells and the second set of battery cells and is configured to provide dynamic energy distribution between the first and second sets of battery cells. A controller controls the one or more switches and the DC-DC converter. The controller is configured to: determine the operating strategy of the battery pack assembly; and in response to the operating strategy of the battery pack assembly, set the first set of battery cells, the second set of battery cells, or both the first set of battery cells and the second set of battery cells to be in electrical communication with the battery connection terminals.

[0023] In some embodiments, the operating strategy includes a charging strategy. The charging strategy includes: performing DCFC on the second set of battery cells while the DC-DC converter distributes energy to the first set of battery cells; or performing DCFC on the first set of battery cells while the DC-DC converter distributes energy to the second set of battery cells; or charging the first and second sets of battery cells simultaneously towards a fully charged SOC without DCFC operation.

[0024] In some embodiments, the operation strategy includes a discharging strategy. The discharging strategy includes: optionally distributing energy between the first and second battery cell sets via the DC-DC converter; and discharging the first battery cell set to drive the vehicle when the second battery cell set is disconnected from the battery connection terminal; or discharging the second battery cell set to drive the vehicle when the first battery cell set is disconnected from the battery connection terminal; or discharging both the first and second battery cell sets to drive the vehicle.

[0025] A first aspect of the present disclosure provides an electrical system, comprising:

[0026] A battery pack assembly, comprising:

[0027] A first battery cell set having a first plurality of energy storage battery cells, the first plurality of energy storage battery cells including a first battery chemistry; and

[0028] A second battery cell set having a second plurality of energy storage battery cells, the second plurality of energy storage battery cells including a second battery chemistry different from the first battery chemistry;

[0029] One or more switches configured to selectively connect the first battery cell set and the second battery cell set in series with a battery connection terminal for electrical communication therebetween;

[0030] A DC-DC converter connected to the first battery cell set and the second battery cell set and configured to provide dynamic energy distribution between the first and second battery cell sets; and

[0031] A controller controlling the one or more switches and the DC-DC converter and configured to:

[0032] Determine an operation strategy for the battery pack assembly; and

[0033] In response to the operation strategy of the battery pack assembly, set the first battery cell set, the second battery cell set, or both the first battery cell set and the second battery cell set to be in electrical communication with the battery connection terminal.

[0034] The electrical system according to the first aspect of the present disclosure, wherein the first battery chemistry includes a high energy density battery chemistry, and the second battery chemistry includes a high charge and discharge rate battery chemistry.

[0035] The electrical system according to the first aspect of the present disclosure, wherein the high energy density battery chemistry includes a lithium-ion battery chemistry, the lithium-ion battery chemistry includes a cathode comprising nickel, cobalt, and manganese (NCM battery chemistry), and wherein the high charge and discharge rate battery chemistry includes a sodium-ion battery chemistry (sodium battery chemistry).

[0036] The electrical system according to the first aspect of the present disclosure, wherein the one or more switches include a first switch and a second switch, the first switch and the second switch are position-controlled by the controller and are configured to be in electrical communication with a first set of battery cells and a second set of battery cells, wherein the first switch has a first switch A position and a second switch A position, and the second switch has a first switch B position and a second switch B position, wherein when the controller places the first switch in the first switch A position and the second switch in the first switch B position, the first set of battery cells is in electrical communication with the battery connection terminal, while the second set of battery cells is disconnected from the battery connection terminal, wherein when the controller places the first switch in the first switch A position and the second switch in the second switch B position, the first set of battery cells and the second set of battery cells are in electrical communication with the battery connection terminal in series, and wherein when the controller places the first switch in the second switch A position and the second switch in the second switch B position, the second set of battery cells is in electrical communication with the battery connection terminal, while the first set of battery cells is disconnected from the battery connection terminal.

[0037] The electrical system according to the first aspect of the present disclosure, wherein the first switch further has a switch A off position and the second switch further has a switch B off position, and wherein when the controller places the first switch in the switch A off position and the second switch in the switch B off position, the battery pack assembly is disconnected from the battery connection terminal.

[0038] The electrical system according to the first aspect of the present disclosure, wherein the one or more switches include a first switch and a second switch, the first switch and the second switch are position-controlled by the controller and are configured to be in electrical communication with a first set of battery cells, wherein the first switch has a first switch A position and a second switch A position, and the second switch has a first switch B position and a switch B off position, wherein when the controller places the first switch in the first switch A position and the second switch in the switch B off position, the first set of battery cells and the second set of battery cells are in electrical communication with the battery connection terminal in series, and wherein when the controller places the first switch in the second switch A position and the second switch in the first switch B position, the first set of battery cells is connected in parallel with the second set of battery cells for electrical communication with the battery connection terminal.

[0039] The electrical system according to the first aspect of the present disclosure, wherein the operation strategy includes a relatively high-energy state of charge (SOC) charging strategy for direct current fast charging (DCFC) for a second set of battery cells having an SOC condition at or above a predetermined SOC threshold, and wherein the relatively high-energy SOC charging strategy includes: performing DCFC on the second set of battery cells towards a predetermined SOC threshold approaching full charge, while the DC-DC converter distributes energy to the first set of battery cells, and wherein if the second set of battery cells reaches the predetermined SOC threshold approaching full charge, the first set of battery cells performs DCFC towards a full charge SOC, while the DC-DC converter distributes energy to the second set of battery cells to charge both the first and second sets of battery cells towards the full SOC.

[0040] The electrical system according to the first aspect of the present disclosure, wherein the predetermined SOC threshold is from about 25% to about 35%, and wherein the predetermined SOC threshold approaching full charge is from about 94% to about 98%.

[0041] The electrical system according to the first aspect of the present disclosure, wherein the operation strategy includes a relatively low-energy SOC charging strategy for a second set of battery cells having an SOC condition at or below a predetermined SOC threshold approaching zero, and wherein the relatively low-energy SOC charging strategy includes:

[0042] performing DCFC on the second set of battery cells towards a predetermined SOC threshold approaching full charge, while the DC-DC converter distributes energy to the first set of battery cells, and wherein if the second set of battery cells reaches the predetermined SOC threshold approaching full charge, the first set of battery cells performs DCFC towards a full charge SOC, while the DC-DC converter distributes energy to the second set of battery cells to charge both the first set of battery cells and the second set of battery cells towards the full charge SOC; or

[0043] charging the first and second sets of battery cells towards the full charge SOC simultaneously without DCFC operation.

[0044] The electrical system according to the first aspect of the present disclosure, wherein the predetermined SOC threshold approaching zero is from about 0% to about 10%, and wherein the predetermined SOC threshold approaching full charge is from about 94% to about 98%.

[0045] The electrical system according to the first aspect of the present disclosure, wherein the operation strategy includes a relatively high SOC discharge strategy for a situation where the SOC of the second battery cell set is higher than a predetermined SOC threshold, and wherein the relatively high SOC discharge strategy includes discharging the first battery cell set and the second battery cell set while the DC-DC converter distributes the energy from the second battery cell set to the first battery cell set until the second battery cell set is at or below the predetermined SOC threshold, and wherein if the second battery cell set is at or below the predetermined SOC threshold, the first and second battery cell sets are discharged while the DC-DC converter distributes the energy from the first battery cell set to the second battery cell set to fully discharge the first and second battery cell sets.

[0046] The electrical system according to the first aspect of the present disclosure, wherein the predetermined SOC threshold is from about 25% to about 35%.

[0047] The electrical system according to the first aspect of the present disclosure, wherein the operation strategy includes a relatively low temperature discharge strategy for a situation where the battery pack assembly is at a predetermined low temperature threshold, and wherein the relatively low temperature discharge strategy includes discharging the second battery cell set while the first battery cell set is disconnected from the battery connection terminal and the DC-DC converter distributes the energy to heat the first battery cell set to a temperature higher than the predetermined low temperature threshold, and wherein when the battery pack assembly is at or above a temperature higher than the predetermined low temperature threshold, the first and second battery cell sets are discharged simultaneously.

[0048] The electrical system according to the first aspect of the present disclosure, wherein the predetermined low temperature threshold is from about -35°C to about -20°C.

[0049] The electrical system according to the first aspect of the present disclosure, wherein the operation strategy includes a relatively low DC voltage condition drive cycle discharge strategy, and the relatively low DC voltage condition drive cycle discharge strategy includes:

[0050] When the second battery cell set is disconnected from the battery connection terminal, discharging the first battery cell set; or

[0051] When the first battery cell set is disconnected from the battery connection terminal, discharging the second battery cell set.

[0052] The electrical system according to the first aspect of the present disclosure, wherein the operation strategy includes a relatively high DC voltage condition drive cycle discharge strategy, and the relatively high DC voltage condition drive cycle discharge strategy includes discharging the first battery cell set and the second battery cell set.

[0053] A second aspect of the present disclosure provides a method of operating an electrical system, the method comprising:

[0054] Determining an operating strategy for a battery pack assembly, wherein the battery pack assembly comprises:

[0055] A first set of battery cells having a first plurality of energy storage battery cells, the first plurality of energy storage battery cells comprising a first battery chemistry; and

[0056] A second set of battery cells having a second plurality of energy storage battery cells, the second plurality of energy storage battery cells comprising a second battery chemistry different from the first battery chemistry;

[0057] In response to the operating strategy of the battery pack assembly, setting the first set of battery cells, the second set of battery cells, or both the first set of battery cells and the second set of battery cells connected in series to be in electrical communication with a battery connection terminal; and

[0058] Optionally, providing dynamic energy distribution between the first set of battery cells and the second set of battery cells in response to the operating strategy of the battery pack assembly.

[0059] A third aspect of the present disclosure provides a vehicle comprising:

[0060] An output device; and

[0061] An electrical system configured to provide electrical energy to the output device, the electrical system comprising:

[0062] A battery pack assembly comprising:

[0063] A first set of battery cells having a first plurality of energy storage battery cells, the first plurality of energy storage battery cells comprising a first battery chemistry; and

[0064] A second set of battery cells having a second plurality of energy storage battery cells, the second plurality of energy storage battery cells comprising a second battery chemistry different from the first battery chemistry;

[0065] One or more switches configured to selectively connect the first set of battery cells and the second set of battery cells in series with a battery connection terminal for electrical communication therebetween, wherein the battery connection terminal is configured to be in electrical communication with the output device to discharge the battery pack assembly and drive the vehicle, and independently in electrical communication with a charger to charge the battery pack assembly;

[0066] to charge the battery pack assembly;

[0067] A DC-DC converter, connected to a first battery cell set and a second battery cell set, and configured to provide dynamic energy distribution between the first and second battery cell sets; and

[0068] A controller, controlling the one or more switches and the DC-DC converter, and configured to:

[0069] Determine an operation strategy of the battery pack assembly; and

[0070] In response to the operation strategy of the battery pack assembly, set the first battery cell set, the second battery cell set, or both the first battery cell set and the second battery cell set to be in electrical communication with the battery connection terminals.

[0071] The vehicle according to the third aspect of the present disclosure, wherein the operation strategy includes a charging strategy, and the charging strategy includes:

[0072] Perform DCFC on the second battery cell set while the DC-DC converter distributes energy to the first battery cell set; or

[0073] Perform DCFC on the first battery cell set while the DC-DC converter distributes energy to the second battery cell set; or

[0074] Charge the first and second battery cell sets simultaneously towards a fully charged SOC without DCFC operation.

[0075] The vehicle according to the third aspect of the present disclosure, wherein the operation strategy includes a discharging strategy, and the discharging strategy includes:

[0076] Optionally distribute energy between the first and second battery cell sets via the DC-DC converter; and

[0077] When the second battery cell set is disconnected from the battery connection terminals, discharge the first battery cell set to drive the vehicle; or

[0078] When the first battery cell set is disconnected from the battery connection terminals, discharge the second battery cell set to drive the vehicle; or

[0079] Discharge the first and second battery cell sets to drive the vehicle.

[0080] When understood in conjunction with the accompanying drawings, the above and other features and advantages of the present disclosure are apparent from the following detailed description of the best mode of implementing the present disclosure. Description of the Drawings

[0081] Figure 1Illustrated is a schematic view of a vehicle including an electrical system and an output device according to an exemplary embodiment.

[0082] Figure 2 Illustrated is a schematic view of a part of an electrical system including a battery pack assembly, a switch, and a DC-DC converter according to an exemplary embodiment.

[0083] Figure 3A Is a graphical representation of an operating strategy for direct current fast charging (DCFC) of an electrical system according to an exemplary embodiment.

[0084] Figure 3B Is a graphical representation of an operating strategy for DCFC of an electrical system according to an exemplary embodiment.

[0085] Figure 3C Is a graphical representation of a comparison of fast charging performance for two different charging scenarios of an electrical system according to an exemplary embodiment.

[0086] Figure 4 Is a graphical representation of an operating strategy for a discharging strategy of an electrical system according to an exemplary embodiment.

[0087] Figure 5 Illustrated is a schematic view of a part of an electrical system including a battery pack assembly, a switch, and a DC-DC converter according to an exemplary embodiment.

[0088] The drawings are not necessarily to scale and may present a somewhat simplified representation of various preferred features of the present disclosure disclosed herein (including, for example, specific dimensions, orientations, positions, and shapes). Details associated with these features will be determined in part by the particular intended application and use environment. Detailed Description

[0089] Referring to the drawings, throughout several figures, like reference numerals correspond to like or similar components. Figure 1 Illustrated is a vehicle 10 including an electrical system 12 and an output device 14 according to an exemplary embodiment. As illustrated, the vehicle 10 is a land electric vehicle (EV).

[0090] Figure 2FIG. illustrates a schematic view of a portion of an electrical system 12 according to an exemplary embodiment. Referring to FIGS. 1-2, electrical system 12 includes a rechargeable energy storage system (RESS) (referred to herein as “battery pack assembly” 16) and a controller 18. Battery pack assembly 16, controller 18, and output device 14 are mounted in a vehicle and communicate with each other. As will be discussed in further detail below, battery pack assembly 16 is configured to generate and store electrical energy through an electrochemical reaction to supply the electrical energy to output device 14 to provide power to vehicle 10 during use, e.g., to provide torque to wheels 20 to move vehicle 10 along road 22. Additionally and as illustrated, battery pack assembly 16 can be recharged via an external charger 24, such as at a charging station or the like.

[0091] Controller 18 is programmable and can include a central processing unit (CPU) that regulates various functions of vehicle 10 including output device 14 and / or battery pack assembly 16. In an exemplary embodiment, controller 18 includes a processor and a tangible non-transitory memory that includes instructions programmed therein for operation of vehicle 10, which includes output device 14 and battery pack assembly 16. In one or more embodiments, controller 18 includes a battery management system (BMS) that controls or otherwise manages the operation of battery pack assembly 16. The memory can be a suitable recordable medium that participates in providing computer-readable data or process instructions. Such a recordable medium can take many forms, including but not limited to non-volatile media and volatile media.

[0092] The non-volatile medium for controller module 16 can include, for example, optical or magnetic disks and other permanent memories. The volatile medium can include, for example, dynamic random access memory (DRAM), which can constitute the main memory. Such instructions can be transmitted through one or more transmission media or via a wireless connection, the transmission media including coaxial cable, copper wire, and fiber optic, including the wires that comprise a system bus coupled to a processor of the computer.

[0093] The memory of controller 18 can also include floppy disks, hard disks, magnetic tapes, other magnetic media, CD-ROMs, DVDs, other optical media, etc. Controller 18 can be configured or equipped with other required computer hardware, such as a high-speed clock, required analog-to-digital (A / D) and / or digital-to-analog (D / A) circuits, input / output circuits and devices (I / O), and appropriate signal conditioning and / or buffering circuits. Algorithms required by or accessible to controller 18, including but not limited to prediction algorithms, algorithms for determining various operating strategies for controlling the operation of battery pack assembly 16, etc., can be stored in the memory and automatically executed to provide the required functions of vehicle 10 including output device 14 and battery pack assembly 16.

[0094] AsFigure 2 As shown, the battery pack assembly 16 includes a battery cell set 26 (e.g., a first battery cell set) having a plurality of energy storage battery cells 28 and a battery cell set 32 (e.g., a second battery cell set) having a plurality of energy storage battery cells 34. As will be discussed further in detail below, the energy storage battery cell 28 includes or comprises a battery chemistry 30, and the energy storage battery cell 34 includes or comprises a battery chemistry 38 that is different from the battery chemistry 30.

[0095] The electrical system 12 further includes switches 40 and 42 disposed along a bus 44 that is in electrical communication with the battery cell sets 26 and 32. Depending on whether the battery cell sets 26 and 32 are respectively discharging or charging, the switches 40 and 42 are configured to selectively connect the battery cell sets 26 and 32 in series with battery connection terminals 46 for electrical communication therebetween, the battery connection terminals 46 being in electrical communication with an output device 14 (load) or a charger 24, respectively. As will be discussed further in detail below, a DC-DC converter 50 is disposed along a bus 48 and connected to the battery cell sets 26 and 32 to provide dynamic energy distribution therebetween (e.g., for energy distribution or transfer from one battery cell set 26 or 32 to the other battery cell set 32 or 26).

[0096] In an exemplary embodiment, a controller 18 controls the switches 40 and 42 and the DC-DC converter 50. Additionally, the controller 18 is operable to determine an operating strategy for the battery pack assembly 16 and set the battery cell set 26, the second battery cell set 32, or both the battery cell sets 26 and 32 in electrical communication with the battery connection terminals 46 in response to the operating strategy of the battery pack assembly 16.

[0097] In an exemplary embodiment, the battery chemistry 30 of the energy storage battery cell 28 is or otherwise includes a high energy density battery chemistry, while the battery chemistry 38 of the energy storage battery cell 34 is or otherwise includes a high charge and discharge rate battery chemistry. In an exemplary embodiment, the high energy density battery chemistry is or includes a lithium ion battery chemistry that includes a cathode formed of nickel, cobalt, and manganese (NCM battery chemistry) or a cathode containing nickel, cobalt, and manganese. In an exemplary embodiment, the high charge and discharge rate battery chemistry includes a sodium ion battery chemistry (sodium battery chemistry).

[0098] Switches 40 and 42 are position - controlled by controller 18. Switches 40 and 42 are configured to be in electrical communication with battery cell sets 26 and 32. As shown, switch 40 has a first switch A position 52 and a second switch A position 54. Similarly, switch 42 has a first switch B position 56 and a second switch B position 58. In an exemplary embodiment, when controller 18 positions switch 40 at the first switch A position 52 and positions switch 42 at the first switch B position 56, battery cell set 26 is in electrical communication with battery connection terminal 46, while battery cell set 32 is disconnected from battery connection terminal 46. Further, when controller 18 positions switch 40 at the first switch A position 52 and positions switch 42 at the second switch B position 58, battery cell set 26 and battery cell set 32 are connected in series and in electrical communication with battery connection terminal 46. Additionally, when controller 18 positions switch 40 at the second switch A position 54 and positions switch 42 at the second switch B position 58, battery cell set 32 is in electrical communication with battery connection terminal 46, while battery cell set 26 is disconnected from battery connection terminal 46.

[0099] In an exemplary embodiment, electrical system 10 is configured to disconnect battery pack assembly 16 from battery connection terminal 46. As shown, switch 40 also has a switch A off position 60 and switch 42 also has a switch B off position 62. In an exemplary embodiment, when controller 18 positions switch 40 at the switch A off position 60 and positions switch 42 at the switch B off position 62, battery pack assembly 16 is disconnected from battery connection terminal 46.

[0100] In an exemplary embodiment, the illustrated electrical system 12 including different battery chemistries provides improved efficiency, increased charge and discharge performance, and greater capacity and enhanced performance based on various operating strategies that utilize the advantages of each different battery chemistry in various scenarios. The following are some non - limiting examples of various operating strategies for electrical system 12.

[0101] Figure 3A is a graphical representation of an operating strategy for direct current fast charging (DCFC) of electrical system 12 according to an exemplary embodiment, where the X - axis represents time (T) and the Y - axis represents state of charge (SOC). Refer to Figure 1-3A In an exemplary embodiment, the operating strategy includes: a relatively high energy state of charge (SOC) charging strategy for DCFC of battery pack assembly 16, and more specifically for the case where battery cell set 32 of battery pack assembly 16 has a relatively high SOC that is at or above a predetermined SOC threshold. In an exemplary embodiment, the predetermined threshold ranges from approximately 25% to approximately 35%, such as approximately 30%.

[0102] In one or more embodiments, a relatively high energy SOC charging strategy includes performing DCFC on the set of battery cells 32 towards a predetermined SOC threshold approaching full charge while the DC-DC converter 50 distributes energy from the set of battery cells 32 to the set of battery cells 26. In an exemplary embodiment, the predetermined SOC threshold approaching full charge is from about 94% to about 98%, such as about 96%. In one or more embodiments, if the set of battery cells 32 reaches or when the set of battery cells 32 reaches the predetermined SOC threshold approaching full charge, then the set of battery cells 26 performs DCFC towards a full charge SOC (e.g., about 100%) while the DC-DC converter 50 distributes energy from the set of battery cells 26 to the set of battery cells 32 to charge both the set of battery cells 26 and 32 towards full SOC.

[0103] Figure 3B is a graphical representation of an operating strategy for DCFC of the electrical system 12 according to an exemplary embodiment, where the X-axis represents time (T) and the Y-axis represents state of charge (SOC). Referring to Figure 1-2 and Figure 3B , in an exemplary embodiment, the operating strategy includes a relatively low energy SOC charging strategy for SOC conditions of the battery pack assembly 16, and more specifically the set of battery cells 32 (or both the set of battery cells 26 and 32) having an SOC at or below a predetermined SOC threshold approaching zero. In an exemplary embodiment, the predetermined SOC threshold approaching zero is from about 0% to about 10%, such as about 0%.

[0104] In one or more embodiments, a relatively low energy SOC charging strategy includes performing DCFC on the set of battery cells 32 towards a predetermined SOC threshold approaching full charge while the DC-DC converter 50 distributes energy to the set of battery cells 26. In one or more embodiments, if the set of battery cells 32 reaches or when the set of battery cells 32 reaches the predetermined SOC threshold approaching full charge, then the set of battery cells 26 performs DCFC towards a full charge SOC while the DC-DC converter 50 distributes energy from the set of battery cells 26 to the set of battery cells 32 to charge both the set of battery cells 26 and 32 towards a full charge SOC (e.g., about 100%). In an exemplary embodiment, the predetermined SOC threshold approaching full charge is from about 94% to about 98%, such as about 96%. Alternatively, the set of battery cells 26 and 32 can be charged towards a full charge SOC simultaneously, e.g., without DCFC operation.

[0105] Figure 3Cis a graphical representation of a fast charging performance comparison of two different charging scenarios of an electrical system according to an exemplary embodiment, where the Y-axis represents the number of miles (M) that can be traveled based on the (one or more) charging scenarios. Bar 64 represents simultaneous charging of battery cell sets 26 and 32 (e.g., which contain NCM battery chemistry and sodium battery chemistry, respectively), such as 10 minutes of DCFC charging. Bar 66 represents DCFC charging of only battery cell set 32 (e.g., which contains sodium battery chemistry) for 10 minutes. As illustrated, for the same amount of charging (e.g., 10 minutes) and charging type (e.g., DCFC), the final driving distance, bar 66 represents 1.9 times that of bar 64 (190 miles versus 100 miles).

[0106] Figure 4 is a graphical representation of an operating strategy for a discharge strategy for electrical system 12 according to an exemplary embodiment, where the X-axis represents time (T) and the Y-axis represents state of charge (SOC). Referring Figure 1-2 and Figure 4 , in an exemplary embodiment, the operating strategy includes a relatively high SOC discharge strategy for cases where the battery pack assembly 16, and more specifically the battery cell set 32 (or both battery cell sets 26 and 32) has an SOC above a predetermined SOC threshold (e.g., from about 40% to about 100%, e.g., almost fully charged). In an exemplary embodiment, the predetermined SOC threshold is from about 25% to about 35%, e.g., about 30%. In an exemplary embodiment, the relatively high SOC discharge strategy includes discharging battery cell sets 26 and 32 while the DC-DC converter 50 distributes energy from battery cell set 32 to battery cell set 26 until battery cell set 32 is at or below the predetermined SOC threshold. If battery cell set 32 is at or below the predetermined SOC threshold or when battery cell set 32 is at or below the predetermined SOC threshold, battery cell sets 26 and 32 are discharged while the DC-DC converter 50 distributes energy from battery cell set 26 to battery cell set 32 to fully discharge battery cell sets 26 and 32.

[0107] Referring again to Figure 1-2, in an exemplary embodiment, the operation strategy includes a relatively low-temperature discharge strategy for when the battery pack assembly is in a predetermined low-temperature threshold condition. In an exemplary embodiment, the predetermined low-temperature threshold is about -20 °C or lower, for example, from about -35 °C to about -20 °C. In one or more embodiments, the relatively low-temperature discharge strategy includes discharging the battery cell set 32 while disconnecting the battery cell set 26 from the battery connection terminal and the DC-DC converter 50 allocates energy to heat the battery cell set 26 to a temperature higher than the predetermined low-temperature threshold. When the battery pack assembly 16 is at or above the temperature of the predetermined low-temperature threshold (e.g., about 0 °C or higher), then the battery cell sets 26 and 32 discharge simultaneously.

[0108] In an exemplary embodiment, the operation strategy includes a relatively low DC voltage condition drive cycle discharge strategy used, for example, during urban driving. The relatively low voltage condition drive cycle discharge strategy includes discharging the battery cell set 26 when the battery cell set 32 is disconnected from the battery connection terminal 46. In an alternative embodiment, the relatively low voltage condition drive cycle discharge strategy includes discharging the battery cell set 32 when the battery cell set 26 is disconnected from the battery connection terminal 46.

[0109] In an exemplary embodiment, the operation strategy includes a relatively high DC voltage condition drive cycle discharge strategy used, for example, during highway driving. The relatively high DC voltage condition drive cycle discharge strategy includes discharging the battery cell sets 26 and 32 simultaneously.

[0110] Figure 5 A schematic view of a part of an electrical system 112 including a battery pack assembly 116, switches 160 and 162, and a DC-DC converter 150 according to an exemplary embodiment is illustrated. The electrical system 112 including the battery pack assembly 116, battery cell sets 126 and 132, the DC-DC converter 150, and the battery connection terminal 46 is Figure 2 similarly configured to the electrical system 12 shown in including the battery pack assembly 16, battery cell sets 26 and 32, the DC-DC converter 50, and the battery connection terminal 46, but differs in that the switches 160 and 162 are arranged to be in electrical communication with the battery cell set 126. In an exemplary embodiment, the switches 160 and 162 (e.g., position-controlled) and the DC-DC converter 150 are controlled by a controller 18 in response to one or more of the operation strategies described above to set the battery cell sets 126 and / or 132 to be in communication with the battery connection terminal 46.

[0111] In an exemplary embodiment, switch 160 has a first switch A position 168 and a second switch A position 170, and switch 162 has a first switch B position 172 and a switch B open position 174. When controller 18 positions switch 160 at the first switch A position 168 and positions switch 162 at the switch B open position 174, battery cell set 126 and battery cell set 132 are connected in series and are in electrical communication with battery connection terminal 46. Additionally, in an exemplary embodiment, when controller 18 positions switch 126 at the second switch A position 170 and positions switch 132 at the first switch B position 172, battery cell set 126 is connected in parallel with battery cell set 132 to be in electrical communication with battery connection terminal 46.

[0112] In an exemplary embodiment, advantageously, the parallel connection of battery cell set 126 with battery cell set 132, thus matching the C-rate charging of battery cell sets 126 and 132, helps to improve the fast charging ability. In an exemplary embodiment, advantageously, the series connection of battery cell set 126 during discharge helps to ensure that both battery cell sets 126 and 132 are depleted simultaneously. In an exemplary embodiment, DC-DC converter 50 can be optional, i.e., it can be removed for some applications, while it can be included for other applications to provide dynamic energy distribution between battery cell sets 126 and 132 in response to the operating strategy of battery pack assembly 116.

[0113] The detailed description and the drawings or figures support and describe the present teachings, but the scope of the present teachings is defined only by the claims. Although some best modes and other embodiments for practicing the present teachings have been described in detail, there are various alternative designs and embodiments for practicing the present teachings as defined in the appended claims.

Claims

1. An electrical system, comprising: A battery pack assembly, comprising: A first battery cell set having a first plurality of energy storage battery cells, the first plurality of energy storage battery cells including a first battery chemistry; and A second battery cell set having a second plurality of energy storage battery cells, the second plurality of energy storage battery cells including a second battery chemistry different from the first battery chemistry; One or more switches configured to selectively connect the first battery cell set and the second battery cell set in series with a battery connection terminal for electrical communication therebetween; A DC-DC converter connected to the first battery cell set and the second battery cell set and configured to provide dynamic energy distribution between the first and second battery cell sets; and A controller controlling the one or more switches and the DC-DC converter and configured to: Determine an operating strategy of the battery pack assembly; and In response to the operating strategy of the battery pack assembly, set the first battery cell set, the second battery cell set, or both the first battery cell set and the second battery cell set to be in electrical communication with the battery connection terminal.

2. The electrical system according to claim 1, wherein the first battery chemistry includes a high energy density battery chemistry, and the second battery chemistry includes a high charge and discharge rate battery chemistry.

3. The electrical system according to claim 2, wherein the high energy density battery chemistry includes a lithium ion battery chemistry, the lithium ion battery chemistry includes a cathode containing nickel, cobalt, and manganese (NCM battery chemistry), and wherein the high charge and discharge rate battery chemistry includes a sodium ion battery chemistry (sodium battery chemistry).

4. The electrical system according to claim 1, wherein the one or more switches include a first switch and a second switch, the first switch and the second switch are position-controlled by the controller and configured to be in electrical communication with the first battery cell set and the second battery cell set, wherein the first switch has a first switch A position and a second switch A position, and the second switch has a first switch B position and a second switch B position, wherein when the controller places the first switch in the first switch A position and the second switch in the first switch B position, the first battery cell set is in electrical communication with the battery connection terminal while the second battery cell set is disconnected from the battery connection terminal, wherein when the controller places the first switch in the first switch A position and the second switch in the second switch B position, the first battery cell set and the second battery cell set are in electrical communication with the battery connection terminal in series, and wherein when the controller places the first switch in the second switch A position and the second switch in the second switch B position, the second battery cell set is in electrical communication with the battery connection terminal while the first battery cell set is disconnected from the battery connection terminal.

5. The electrical system according to claim 4, wherein the first switch further has a switch A off position and the second switch further has a switch B off position, and wherein when the controller places the first switch in the switch A off position and the second switch in the switch B off position, the battery pack assembly is disconnected from the battery connection terminals.

6. The electrical system according to claim 1, wherein the one or more switches include a first switch and a second switch, the first switch and the second switch are position-controlled by the controller and are configured to be in electrical communication with a first set of battery cells, wherein the first switch has a first switch A position and a second switch A position, and the second switch has a first switch B position and a switch B off position, wherein when the controller places the first switch in the first switch A position and the second switch in the switch B off position, the first set of battery cells and the second set of battery cells are electrically connected in series to the battery connection terminals, and wherein when the controller places the first switch in the second switch A position and the second switch in the first switch B position, the first set of battery cells is connected in parallel with the second set of battery cells for electrical communication with the battery connection terminals.

7. The electrical system according to claim 1, wherein the operating strategy includes a relatively high energy state of charge (SOC) charging strategy for direct current fast charging (DCFC) for a situation where the second battery cell set has an SOC at or above a predetermined SOC threshold, wherein the relatively high energy SOC charging strategy includes: Performing DCFC on the second set of battery cells towards a predetermined SOC threshold approaching full charge, while the DC-DC converter distributes energy to the first set of battery cells, and wherein if the second set of battery cells reaches the predetermined SOC threshold approaching full charge, the first set of battery cells performs DCFC towards a full charge SOC, while the DC-DC converter distributes energy to the second set of battery cells to charge both the first and second sets of battery cells towards the full SOC.

8. The electrical system according to claim 7, wherein the predetermined SOC threshold is from about 25% to about 35%, and wherein the predetermined SOC threshold approaching full charge is from about 94% to about 98%.

9. The electrical system according to claim 1, wherein the operating strategy includes a relatively low energy SOC charging strategy for an SOC condition where the second set of battery cells has an SOC at or below a predetermined SOC threshold approaching zero, wherein the relatively low energy SOC charging strategy includes: Performing DCFC on the second set of battery cells towards a predetermined SOC threshold approaching full charge, while the DC-DC converter distributes energy to the first set of battery cells, and wherein if the second set of battery cells reaches the predetermined SOC threshold approaching full charge, the first set of battery cells performs DCFC towards a full charge SOC, while the DC-DC converter distributes energy to the second set of battery cells to charge both the first set of battery cells and the second set of battery cells towards the full charge SOC; or Charging the first and second sets of battery cells simultaneously towards the full charge SOC without DCFC operation.

10. The electrical system according to claim 9, wherein the predetermined SOC threshold close to zero is from about 0% to about 10%, and wherein the predetermined SOC threshold close to full charge is from about 94% to about 98%.

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