Battery system and method of use in a battery system

Abstract

The present invention discloses a battery system and a method of use in the battery system. The battery system includes an auxiliary power module configured to support an auxiliary load. A first contactor switch is connected between a first battery pack and a second battery pack, and a second contactor switch is in series with the first contactor switch. A controller determines to open or close the first contactor switch and the second contactor switch depending on whether the battery packs are being charged in a high voltage mode or a low voltage mode. When in the high voltage mode, both of the contactor switches are closed, and when in the low voltage mode, at least one of the contactor switches is open. At least one of the first battery pack and the second battery pack operates to power the auxiliary power module when charging at least one of the first battery pack and the second battery pack, regardless of whether the battery packs are in the high voltage mode or the low voltage mode.

Description

Background Art

[0001] An electric powertrain often includes one or more polyphase / alternating current (AC) rotating machines constructed of a wound stator and a magnetic rotor. The stator windings are connected to the AC side of a power converter, where the direct current (DC) side of the power converter is connected to the positive and negative rails of a DC voltage bus. When the machine functions as a traction motor, switching control of the ON / OFF states of the respective semiconductor switches of the power converter generates an AC output voltage at a level suitable for exciting the stator windings. The sequentially excited stator windings produce a rotating magnetic field that ultimately interacts with the rotor magnetic field to produce machine rotation and motor output torque.

[0002] The DC voltage bus is electrically connected to a voltage source that is typically embodied as a multi-cell battery pack in mobile applications. The rated voltage of the current battery pack types used to energize the propulsion function continues to increase to meet the demand for an extended electric drive range. The battery charging infrastructure and associated charging methods are likewise continuing to evolve. For example, some emerging DC fast charging (DCFC) stations are capable of providing a charging voltage of 800V or higher, while older "legacy" DCFC stations may be capable of providing a lower charging voltage, such as 400V. To accommodate a wide range of possible charging voltages, some battery systems utilize multiple battery packs instead of individual cells. For example, the respective battery packs of some battery systems can be selectively connected in parallel during propulsion operation and reconfigured into a series connection during high voltage charging operation, where the series connection of such a battery system configuration enables the utilization of a higher charging voltage. Summary of the Invention

[0003] The present disclosure provides a method of using a battery system. The battery system includes: positive and negative direct current (DC) voltage bus rails; a first battery pack and a second battery pack connected to the positive and negative DC bus rails; and an auxiliary power module configured to support an auxiliary load. The battery system further includes: a first contactor switch connected between the first battery pack and the second battery pack; and a second contactor switch in series with the first contactor switch between the first battery pack and the second battery pack. A controller determines to open or close the first contactor switch and the second contactor switch depending on whether the first battery pack and the second battery pack are being charged in a high voltage mode or a low voltage mode. When in the high voltage mode, both the first contactor switch and the second contactor switch are closed, and the high voltage mode electrically connects the first battery pack and the second battery pack in a series arrangement. When in the low voltage mode, at least one of the first contactor switch and the second contactor switch is open, and the low voltage mode electrically connects the first battery pack and the second battery pack in a parallel arrangement. At least one of the first battery pack and the second battery pack operates to power the auxiliary power module when charging at least one of the first battery pack and the second battery pack, regardless of whether the first battery pack and the second battery pack are in the high voltage mode or the low voltage mode.

[0004] Optionally, the method includes one or more of the following:

[0005] A) determining an average energy difference based on the maximum available energy level of the first battery pack and the remaining energy level to full charge, and determining an average energy difference based on the maximum available energy level of the second battery pack and the remaining energy level to full charge;

[0006] B) selecting one of the first battery pack and the second battery pack to supply power to the auxiliary power module based on the smaller average energy difference;

[0007] C) when in the high voltage mode, changing the charge from the first battery pack to the second battery pack, and changing the power supply from the second battery pack to the first battery pack to operate the auxiliary power module;

[0008] D) signaling a decrease in the current of the second battery pack during a power transition between the first battery pack and the second battery pack;

[0009] E) When in the high voltage mode, charging is switched from the first battery pack to the second battery pack, and the power supply is switched from the second battery pack to the first battery pack to operate the auxiliary power module, based on the average energy difference compiled from the maximum available energy level of the first battery pack and the remaining energy level to full charge, and the average energy difference compiled from the maximum available energy level of the second battery pack and the remaining energy level to full charge;

[0010] F) Monitor the average energy difference based on the maximum available energy level of the first battery pack and the remaining energy level to full charge, and monitor the average energy difference based on the maximum available energy level of the second battery pack and the remaining energy level to full charge, to determine whether to switch the power supply from one of the first battery pack and the second battery pack to the auxiliary power module to the power supply from the other of the first battery pack and the second battery pack to the auxiliary power module;

[0011] G) Monitor the remaining charge time of the first battery pack and the second battery pack to determine whether to switch the power supply from one of the first battery pack and the second battery pack to the auxiliary power module to the power supply from the other of the first battery pack and the second battery pack to the auxiliary power module;

[0012] H) Monitor the charge state of the first battery pack and the charge state of the second battery pack to determine whether to switch the power supply from one of the first battery pack and the second battery pack to the auxiliary power module to the power supply from the other of the first battery pack and the second battery pack to the auxiliary power module;

[0013] I) Compare the current in the parallel arrangement and the current in the series arrangement;

[0014] J) If the current in the parallel arrangement is greater than the current in the series arrangement, charge the first battery pack and the second battery pack in the parallel arrangement;

[0015] K) If the current in the parallel arrangement is less than the current in the series arrangement, disconnect one of the first battery pack and the second battery pack without charging, and then charge the other of the first battery pack and the second battery pack;

[0016] L) Signal at least one of the first contactor switch and the second contactor switch to open during the low voltage mode, such that the first battery pack and the second battery pack are in a parallel arrangement, in which both the first battery pack and the second battery pack supply power to the auxiliary power module while both are being charged;

[0017] M) Signal to close the first contactor switch and the second contactor switch during the high-voltage mode, such that the first battery pack and the second battery pack are arranged in series, in which arrangement, one of the first battery pack and the second battery pack supplies power to the auxiliary power module, and the other of the first battery pack and the second battery pack is being charged;

[0018] N) When the first battery pack and the second battery pack are arranged in series, charging is switched from the first battery pack to the second battery pack, and power supply to operate the auxiliary power module is switched from the second battery pack to the first battery pack; and

[0019] O) When the first battery pack and the second battery pack are arranged in parallel, no charging transition occurs.

[0020] The present disclosure also provides a battery system, which includes: positive and negative direct current (DC) voltage bus rails; a first battery pack and a second battery pack, each connected to the positive and negative DC voltage bus rails; and an auxiliary power module configured to support an auxiliary load. The auxiliary power module is in electrical communication with at least one of the first battery pack and the second battery pack. The battery system further includes: a first contactor switch connected between the first battery pack and the second battery pack; and a second contactor switch connected in series with the first contactor switch between the first battery pack and the second battery pack. The battery system further includes a controller that communicates with the first contactor switch and the second contactor switch to selectively open and close the first contactor switch and the second contactor switch depending on whether the first battery pack and the second battery pack are in a high-voltage mode or a low-voltage mode. When in the high-voltage mode, both the first contactor switch and the second contactor switch are closed, and the high-voltage mode electrically connects the first battery pack and the second battery pack in a series arrangement. When in the low-voltage mode, at least one of the first contactor switch and the second contactor switch is open, and the low-voltage mode electrically connects the first battery pack and the second battery pack in a parallel arrangement. The controller is configured to: determine which of the first battery pack and the second battery pack operates to supply power to the auxiliary power module when at least one of the first battery pack and the second battery pack is being charged, regardless of whether the first battery pack and the second battery pack are in the high-voltage mode or the low-voltage mode.

[0021] Optionally, the battery system includes one or more of the following:

[0022] A) The controller is configured to: determine an average energy difference based on the maximum available energy level of the first battery pack and the remaining energy level to full charge, and determine an average energy difference based on the maximum available energy level of the second battery pack and the remaining energy level to full charge;

[0023] B) The controller selects one of the first battery pack and the second battery pack to supply power to the auxiliary power module based on the smaller average energy difference;

[0024] C) The controller is configured to: during the low voltage mode, signal at least one of the first contactor switch and the second contactor switch to open, such that the first battery pack and the second battery pack are arranged in parallel, in which arrangement, when both the first battery pack and the second battery pack are being charged, both the first battery pack and the second battery pack supply power to the auxiliary power module;

[0025] D) The controller is configured to: when in the high voltage mode, transfer charging from the first battery pack to the second battery pack, and transfer power supply from the second battery pack to supply from the first battery pack to operate the auxiliary power module;

[0026] E) During the power transfer between the first battery pack and the second battery pack, the controller signals a decrease in the second battery pack current;

[0027] F) The controller is configured to: monitor the average energy difference based on the maximum available energy level of the first battery pack and the remaining energy level to full charge, and monitor the average energy difference based on the maximum available energy level of the second battery pack and the remaining energy level to full charge, to determine whether to transfer power supply from one of the first battery pack and the second battery pack to the auxiliary power module to power supply from the other of the first battery pack and the second battery pack to the auxiliary power module;

[0028] G) The controller is configured to: monitor the remaining charge time of the first battery pack and the second battery pack to determine whether to transfer power supply from one of the first battery pack and the second battery pack to the auxiliary power module to power supply from the other of the first battery pack and the second battery pack to the auxiliary power module;

[0029] H) The controller is configured to: monitor the charge state of the first battery pack and the charge state of the second battery pack to determine whether to transfer power supply from one of the first battery pack and the second battery pack to the auxiliary power module to power supply from the other of the first battery pack and the second battery pack to the auxiliary power module;

[0030] I) The controller is configured to compare the current in the parallel arrangement and the current in the series arrangement, and the controller is configured to: if the current in the parallel arrangement is greater than the current in the series arrangement, allow charging of the first battery pack and the second battery pack to be completed in the parallel arrangement; and

[0031] J) The controller is configured to compare the current in the parallel arrangement and the current in the series arrangement, and the controller is configured to: if the current in the parallel arrangement is less than the current in the series arrangement, disconnect the charging of one of the first battery pack and the second battery pack, and then select the other of the first battery pack and the second battery pack for charging.

[0032] The present invention also discloses the following technical solutions:

[0033] Solution 1. A method of using a battery system, the battery system comprising: positive and negative direct current (DC) voltage bus rails; a first battery pack and a second battery pack connected to the positive and negative DC bus rails; an auxiliary power module configured to support an auxiliary load; a first contactor switch connected between the first battery pack and the second battery pack; and a second contactor switch connected in series with the first contactor switch between the first battery pack and the second battery pack, the method comprising:

[0034] Determining, via a controller, whether to open or close the first contactor switch and the second contactor switch depending on whether the first battery pack and the second battery pack are being charged in a high voltage mode or a low voltage mode;

[0035] wherein, when in the high voltage mode, both the first contactor switch and the second contactor switch are closed, and the high voltage mode electrically connects the first battery pack and the second battery pack in a series arrangement;

[0036] wherein, when in the low voltage mode, at least one of the first contactor switch and the second contactor switch is open, and the low voltage mode electrically connects the first battery pack and the second battery pack in a parallel arrangement; and

[0037] Operating at least one of the first battery pack and the second battery pack to power the auxiliary power module when charging at least one of the first battery pack and the second battery pack, regardless of whether the first battery pack and the second battery pack are in the high voltage mode or the low voltage mode.

[0038] Solution 2. The method according to Solution 1, further comprising:

[0039] Determining an average energy difference based on the maximum available energy level of the first battery pack and the remaining energy level to full charge, and determining an average energy difference based on the maximum available energy level of the second battery pack and the remaining energy level to full charge; and

[0040] Selecting one of the first battery pack and the second battery pack to supply power to the auxiliary power module based on the smaller average energy difference.

[0041] Solution 3. The method according to Solution 1 further includes: when in the high-voltage mode, changing charging from the first battery pack to the second battery pack, and changing the power supply from the second battery pack to the first battery pack to operate the auxiliary power module.

[0042] Solution 4. The method according to Solution 3 further includes: during the power transition between the first battery pack and the second battery pack, signaling a decrease in current of the second battery pack.

[0043] Solution 5. The method according to Solution 3, wherein when in the high-voltage mode, changing charging from the first battery pack to the second battery pack, and changing the power supply from the second battery pack to the first battery pack to operate the auxiliary power module is based on the average energy difference aggregated from the maximum available energy level of the first battery pack and the remaining energy level to full charge, and the average energy difference aggregated from the maximum available energy level of the second battery pack and the remaining energy level to full charge.

[0044] The method according to Solution 3 further includes: monitoring the average energy difference based on the maximum available energy level of the first battery pack and the remaining energy level to full charge, and monitoring the average energy difference based on the maximum available energy level of the second battery pack and the remaining energy level to full charge to determine whether to change the power supply from one of the first battery pack and the second battery pack to the auxiliary power module to the power supply from the other of the first battery pack and the second battery pack to the auxiliary power module.

[0045] Solution 7. The method according to Solution 6 further includes: monitoring the remaining charge time of the first battery pack and the second battery pack to determine whether to change the power supply from one of the first battery pack and the second battery pack to the auxiliary power module to the power supply from the other of the first battery pack and the second battery pack to the auxiliary power module.

[0046] Solution 8. The method according to Solution 7 further includes: monitoring the charge state of the first battery pack and the charge state of the second battery pack to determine whether to change the power supply from one of the first battery pack and the second battery pack to the auxiliary power module to the power supply from the other of the first battery pack and the second battery pack to the auxiliary power module.

[0047] Solution 9. The method according to Solution 1 further includes:

[0048] Compare the current in the parallel arrangement and the current in the series arrangement; and

[0049] If the current in the parallel arrangement is greater than the current in the series arrangement, charge the first battery pack and the second battery pack in the parallel arrangement.

[0050] Solution 10. The method according to Solution 1, further comprising:

[0051] Compare the current in the parallel arrangement and the current in the series arrangement; and

[0052] If the current in the parallel arrangement is less than the current in the series arrangement, disconnect the charging of one of the first battery pack and the second battery pack, and then charge the other of the first battery pack and the second battery pack.

[0053] Solution 11. The method according to Solution 1, further comprising: signaling at least one of the first contactor switch and the second contactor switch to open during the low voltage mode, such that the first battery pack and the second battery pack are in the parallel arrangement, in which both the first battery pack and the second battery pack supply power to the auxiliary power module while both the first battery pack and the second battery pack are being charged.

[0054] Solution 12. The method according to Solution 1, further comprising: signaling the first contactor switch and the second contactor switch to close during the high voltage mode, such that the first battery pack and the second battery pack are in the series arrangement, in which one of the first battery pack and the second battery pack supplies power to the auxiliary power module and the other of the first battery pack and the second battery pack is being charged.

[0055] Solution 13. The method according to Solution 1:

[0056] It further comprises: when the first battery pack and the second battery pack are in the series arrangement, changing the charging from the first battery pack to the second battery pack, and changing the power supply from the second battery pack to the first battery pack to operate the auxiliary power module; and

[0057] wherein, when the first battery pack and the second battery pack are in the parallel arrangement, no such change in charging occurs.

[0058] Solution 14. A battery system, comprising:

[0059] Positive and negative direct current (DC) voltage bus rails;

[0060] A first battery pack and a second battery pack, each connected to the positive and negative DC voltage bus rails;

[0061] An auxiliary power module configured to support an auxiliary load, and the auxiliary power module is in electrical communication with at least one of the first battery pack and the second battery pack;

[0062] A first contactor switch connected between the first battery pack and the second battery pack;

[0063] A second contactor switch in series with the first contactor switch between the first battery pack and the second battery pack;

[0064] A controller in communication with the first contactor switch and the second contactor switch to selectively open and close the first contactor switch and the second contactor switch depending on whether the first battery pack and the second battery pack are in a high voltage mode or a low voltage mode;

[0065] Wherein, when in the high voltage mode, both the first contactor switch and the second contactor switch are closed, and the high voltage mode electrically connects the first battery pack and the second battery pack in a series arrangement;

[0066] Wherein, when in the low voltage mode, at least one of the first contactor switch and the second contactor switch is open, and the low voltage mode electrically connects the first battery pack and the second battery pack in a parallel arrangement; and

[0067] Wherein, the controller is configured to: determine which of the first battery pack and the second battery pack is operating to supply power to the auxiliary power module when at least one of the first battery pack and the second battery pack is being charged, regardless of whether the first battery pack and the second battery pack are in the high voltage mode or the low voltage mode.

[0068] Solution 15. The system according to Solution 14, wherein the controller is configured to: determine an average energy difference based on the maximum available energy level of the first battery pack and the remaining energy level to full charge, and determine an average energy difference based on the maximum available energy level of the second battery pack and the remaining energy level to full charge.

[0069] Solution 16. The system according to Solution 15, wherein the controller selects one of the first battery pack and the second battery pack to supply power to the auxiliary power module based on the smaller average energy difference.

[0070] Solution 17. The system according to Solution 14, wherein the controller is configured to: during the low voltage mode, signal at least one of the first contactor switch and the second contactor switch to open, such that the first battery pack and the second battery pack are in the parallel arrangement, in which both the first battery pack and the second battery pack supply power to the auxiliary power module when both the first battery pack and the second battery pack are being charged.

[0071] Solution 18. The system according to Solution 14, wherein the controller is configured to: when in the high voltage mode, transfer charging from the first battery pack to the second battery pack, and change the power supply from the second battery pack to the first battery pack to operate the auxiliary power module.

[0072] Solution 19. The system according to Solution 18, wherein during the power transfer between the first battery pack and the second battery pack, the controller signals a decrease in the current of the second battery pack.

[0073] Solution 20. The system according to Solution 18:

[0074] wherein the controller is configured to: monitor the average energy difference based on the maximum available energy level of the first battery pack and the remaining energy level to full charge, and monitor the average energy difference based on the maximum available energy level of the second battery pack and the remaining energy level to full charge, to determine whether to change the power supply from one of the first battery pack and the second battery pack to the auxiliary power module to the power supply from the other of the first battery pack and the second battery pack to the auxiliary power module;

[0075] wherein the controller is configured to: monitor the remaining charging time of the first battery pack and the second battery pack to determine whether to change the power supply from one of the first battery pack and the second battery pack to the auxiliary power module to the power supply from the other of the first battery pack and the second battery pack to the auxiliary power module;

[0076] wherein the controller is configured to: monitor the charge state of the first battery pack and the charge state of the second battery pack to determine whether to change the power supply from one of the first battery pack and the second battery pack to the auxiliary power module to the power supply from the other of the first battery pack and the second battery pack to the auxiliary power module;

[0077] Wherein, the controller is configured to compare the current in the parallel arrangement and the current in the series arrangement, and the controller is configured to: if the current in the parallel arrangement is greater than the current in the series arrangement, allow charging of the first battery pack and the second battery pack to be completed in the parallel arrangement; and

[0078] Wherein, the controller is configured to compare the current in the parallel arrangement and the current in the series arrangement, and the controller is configured to: if the current in the parallel arrangement is less than the current in the series arrangement, disconnect the charging of one of the first battery pack and the second battery pack, and then select the other of the first battery pack and the second battery pack for charging.

[0079] The detailed description and the drawings or figures support and describe the present disclosure, but the scope of the claims of the present disclosure is defined solely by the claims. Although some of the best modes and other configurations for implementing the claims have been described in detail, there are various alternative designs and configurations for practicing the disclosure defined in the appended claims. Description of the Drawings

[0080] Figure 1 is a schematic illustration of an exemplary mobile platform that uses a battery system undergoing direct current fast charging (DCFC) operation.

[0081] Figure 2 is a schematic circuit diagram of the battery system.

[0082] Figure 3 is a table for controlling possible series and parallel operation modes of the battery system and corresponding switching states.

[0083] Figure 4 is a chart of the charging states of the first battery pack and the second battery pack, which is aligned with a chart of the station current from an off-vehicle DCFC station that charges the first battery pack and the second battery pack.

[0084] Figure 5 is a description of a method for using a Figures 1-4 battery system according to the present disclosure. Detailed Description of the Invention

[0085] Those of ordinary skill in the art will recognize that all directional references (e.g., above, below, upward, upper, downward, lower, top, bottom, left, right, vertical, horizontal, etc.) are used to describe the figures to assist the reader's understanding and do not represent a limitation on the scope of the disclosure as defined by the appended claims (e.g., position, orientation, use, etc.). Additionally, the term "substantially" can refer to a slight imprecision or slight variation in a condition, quantity, value, or dimension, some of which are within manufacturing tolerances or variances. As used herein, the phrase "at least one of..." should be interpreted to include a non-exclusive logical "or" depending on the number of components, i.e., A and / or B, etc.

[0086] Referring to the accompanying drawings, in which like reference numerals indicate like or corresponding parts throughout the several views, there is generally shown in Figure 1 a movable platform 10, such as a vehicle (or "transportation vehicle"). The movable platform 10 may include an electric powertrain 11 and a battery system 12, which may be a multi-pack battery system 12 including one or more battery packs 14A, 14B. The battery system 12 may include a positive direct current (DC) voltage bus rail 16 + and a negative direct current (DC) voltage bus rail 16 - , where the first battery pack 14A and the second battery pack 14B are each connected to the positive DC voltage bus rail 16 + and the negative DC voltage bus rail 16 - . It will be appreciated that more than two battery packs 14A, 14B may be connected to the bus rails 16 + 、16 - .

[0087] In Figure 1 an example configuration, the electric powertrain 11 powers the electric propulsion function of the movable platform 10, which is a Figure 1 motor vehicle in Figure 1 . Non-limiting examples of transportation vehicles may include cars, trucks, motorcycles, off-road vehicles, agricultural vehicles, watercraft, airplanes, rail vehicles, or any other suitable movable platform. Additionally, the vehicle may be a hybrid vehicle, an electric vehicle, etc. It will be appreciated that alternatively, non-transportation vehicle applications, such as agricultural equipment, fixed platforms, stationary or mobile power plants, robots, conveyors, transportation platforms, etc., may be used. Thus, the battery system 12 described herein may be used in a rechargeable power system for vehicle or non-vehicle applications. For illustrative purposes, the movable platform 10 of Figure 1 will be described hereinafter in the context of a motor vehicle without generally limiting the teachings to vehicle applications.

[0088] The mobile platform 10 is shown undergoing direct current fast charging (DCFC) operation, where the battery system 12 is electrically connected to an out-of-vehicle DCFC station 18, e.g., via a vehicle charging port 20 connected to the body 22 of the mobile platform 10, and the mobile platform is internally connected to a DC charging connector using a length of high voltage charging cable 24. Although not shown in Figure 1 the end connectors of the charging cable 24 can be SAE J1772, CHAdeMO charging connectors, or other suitable country- or application-specific charge couplers or plugs.

[0089] The mobile platform 10 can include front wheels 26F and rear wheels 26R that engage the road surface. The front wheels 26F and rear wheels 26R can be connected to independent front drive axles 28F and rear drive axles 28R. In an all-wheel drive (AWD) configuration, the drive axles 28F, 28R can be powered individually by independent rotary motors 30 (M E ), with each rotary motor acting as an electric traction motor via a corresponding power converter module 32, as Figure 2 shown and described below.

[0090] The battery system 12 is electrically connected to the DCFC station and electrical loads, which include but are not limited to one or more power converter modules 32 ( Figure 2 PIM-A, PIM-B in ), an auxiliary power module 34 (APM), and an on-board charging module 36 (OBCM) (each of the APM and OBCM is part of an integrated power electronics module 38 (IPEO)), another on-board charging module (OBCDM), an air conditioning control module, etc. In Figure 2 the IPEO 38, shown as part of the circuit, is also shown enlarged separately from the circuit to illustrate the APM 34 and OBCM 36 that are part of the IPEO 38. The auxiliary power module 34 is configured to support auxiliary loads, such as accessories, which can include 12-volt accessories or other low voltage level accessories. The auxiliary power module 34 is in electrical communication with at least one of the first battery pack 14A and the second battery pack 14B. In other words, the auxiliary power module 34 can be electrically connected to the first battery pack 14A or the second battery pack 14B or both battery packs 14A, 14B.

[0091] Referring to Figure 2 , the electrical loads can also include one or more rotary motors 30, such as the motor 30 (M E) It will be appreciated that another electric motor 30 may be connected to PIM-A 32. PIM-A 32 may be utilized with an electric motor 30 connected to the front wheel 26F of the movable platform 10 (F-PIM), and PIM-B 32 may be utilized with an electric motor 30 connected to the rear wheel 26R of the movable platform 10. In some configurations, optionally, PIM-B 32 may include a power converter module 32 for the electric motor 30 driving the left wheel 26R (L-PIM), and a power converter module 32 for the electric motor 30 driving the right wheel 26R (R-PIM).

[0092] The power converter module 32 (such as PIM-A or PIM-B) uses pulse width modulation, pulse density modulation, or other suitable techniques to generate a multiphase / AC voltage (VAC) through internal switching control. Continuing Figure 2 , the AC voltage excites the phase windings of the electric motor(s) 30 to thereby generate a motor torque (arrow T M ) on the rotor, and this motor torque is output to the drive axles 28F, 28R to drive one or more of the wheels 26F, 26R. Although one electric motor 30 is shown Figure 2 in, PIM-A 32 connected to the battery pack 14B may similarly have a corresponding electric motor 30, for example to enable an all-wheel drive mode or to power one of the drive axles 28F, 28R Figure 1 independently.

[0093] The battery packs 14A, 14B (which may use lithium-ion, zinc-air, nickel-metal hydride, lead-acid, or other battery chemistries suitable for the application) are selectively recharged via the DCFC charging voltage V CH from an out-of-vehicle DCFC station 18. When the movable platform 10 is in operation, the controller 40 performs a modulated switching control via a control signal ( Figure 1 arrow CC in O ) to ultimately excite one or more electric motors 30 (see Figure 2 ) to generate a motor torque (T M ) and deliver it to one or more of the wheels 26F, 26R, and thereby propel the movable platform 10 and / or perform other useful work. Thus, the battery packs 14A, 14B and the controller 40 together form a battery system 12, which has other possible components (such as thermal management / cooling and power electronics hardware), and these other possible components may be omitted in the figure for clarity of illustration. Thus, generally, the controller 40 may be in electrical communication with the battery system 12. For example, the controller 40 may control the battery system 12 to charge the battery packs 14A, 14B and select which of the battery packs 14A, 14B will power the auxiliary power module 34.

[0094] The controller 40 may be a host machine or a distributed system, such as a computer (such as a digital computer or a microcomputer). The controller 40 includes a processor P and a memory M, wherein the memory M includes a tangible non-transitory memory (e.g., read-only memory) of an amount suitable for the application, whether optical, magnetic, flash or other forms. Instructions may be stored in the memory M of the controller 40 and automatically executed via the processor P of the controller 40 to provide corresponding control functions. The controller 40 also includes a random access memory, an electrically erasable programmable read-only memory, etc., of an amount sufficient for the application, as well as a high-speed clock, analog-to-digital and digital-to-analog circuits, and input / output circuits and devices, and appropriate signal conditioning and buffering circuits. Therefore, the controller 40 may include all software, hardware, memory, algorithms, connections, sensors, etc. necessary for control (e.g., charging the battery system 12 and powering various components such as (one or more) motors 30 and auxiliary power modules 34). It will be understood that the controller 40 may also include any device capable of analyzing data from various sensors, comparing data, and making necessary decisions required to control the battery system 12. Optionally, more than one controller 40 may be utilized. The controller 40 is programmed to execute instructions embodying the method 100 of using the battery system 12, wherein the controller 40: receives an input signal (arrow CC I ), the input signal indicates the charging mode of the driving request or autonomous request of the battery pack 14A, 14B; and in response, the control signal (CC O ) are output to battery packs 14A and 14B.

[0095] Available as Figure 1 The input signal (arrow CC) is determined during DCFC operation as part of the ongoing communication between the controller 40 and the DCFC station. I ) of some of the above. This communication occurs when the mobile platform 10 is connected to a DCFC station, such as when the DCFC station increases its maximum charging voltage V CH When communicated to the controller 40. In the drive / propulsion mode, the operator request or autonomously determined propulsion request may cause the controller 40 to establish a parallel connection (P connection) configuration of the battery packs 14A, 14B. In other words, when in the P connection configuration, the battery packs 14A, 14B are arranged in parallel. During certain DCFC operations, the controller 40 may selectively reconfigure the battery packs 14A, 14B into a series connection (S connection) configuration to utilize the charging voltage V CH , as now will refer to Figure 2 In other words, when in the S-connection configuration, the battery packs 14A, 14B are arranged in series.

[0096] refer to Figure 2, the battery system 12 can be part of a rechargeable energy storage system (RESS) 42 constructed from two or more battery packs 14A, 14B, each battery pack having an associated battery module 44 in the form of interconnected battery cells, battery cell sensing circuitry, etc. These battery modules 44 are substantially identical, i.e., having the same internal components and equal voltage capacity, e.g., 300 - 500 volts DC (VDC), although other voltage levels are conceivable. It will be appreciated that more than two battery packs X can be used in other configurations, where, for illustrative purposes, two battery packs 14A, 14B are used hereinafter. The battery packs 14A, 14B can be arranged in a P - connection configuration, where the battery modules 44 in each of the battery packs 14A, 14B have a corresponding module voltage V m , and where the battery pack voltage V B equals the module voltage V m .

[0097] As an illustrative example, the module voltage V m can be in the range of approximately 300 - 500V. The charging voltage V Figure 1 from a CH DCFC station can be in the same range, or the charging voltage V CH can be higher, e.g., 600 - 1000V, where other battery and charging voltage levels are also available within the scope of the present disclosure. Thus, in the P - connection configuration, the battery system 12 has a battery pack voltage V B , which is defined by the potential difference between the positive DC bus rail 16 + and the negative DC bus rail 16 - (or more precisely, the positive and negative terminals of the battery system 12), and which is equal to the module voltage V m . However, in the S - connection configuration, the battery pack voltage V B is a multiple of the module voltage V m , where the multiple is the number of S - connection type battery packs 14A, 14B used in the construction of the battery system 12.

[0098] The switching control circuit is constructed from a plurality of switches SA1, SA2, SA3, PCA, SB1, SB2, SB3, PCB, S1, S2, OB1, OB2, as Figure 2As shown, the figure is an illustration of the reconfigurable nature of the battery system 12. In an actual implementation, each of the switches SA1, SA2, SA3, PCA, SB1, SB2, SB3, PCB, S1, S2, OB1, OB2 depicted may be embodied as multiple switches. The switches SA1, SA2, SA3, PCA, SB1, SB2, SB3, PCB, S1, S2, OB1, OB2 may be configured as: solid-state switches; mechanical switches, i.e., spring-biased contactors, which have an ON / conduction state when closed and an OFF / non-conduction state when open; electromechanical switches, such as contactors or relays, which are capable of blocking current flow in either direction; semiconductor switches, such as IGBTs or MOSFETs, with or without anti-parallel-connected diodes, employed individually or in combination, etc., and / or combinations thereof. Switch SA2 is connected between the negative (-) terminal of the battery module 44 of the first battery pack 14A and the negative DC bus rail 16 - while switch SB1 is connected between the positive (+) terminal of the battery module 44 of the second battery pack 14B and the positive DC bus rail 16 + therebetween.

[0099] Depending on the position of the switches SA1, SA2, SA3, PCA, SB1, SB2, SB3, PCB, S1, S2, OB1, OB2, the auxiliary power module 34 can be electrically connected to the first battery pack 14A or the second battery pack 14B or both battery packs 14A, 14B. The first contactor switch S1 is connected between the first battery pack 14A and the second battery pack 14B, and the second contactor switch S2 is connected in series with the first contactor switch S1 between the first battery pack 14A and the second battery pack 14B. In the figure, the first contactor switch S1 can be switch S1, and the second contactor switch S2 can be switch S2. Thus, the switches S1, S2 are then placed between the first battery pack 14A and the second battery pack 14B. Specifically, one side (X) of the switch S1 is connected between the switch SA2 and the negative (-) terminal of the battery module 44 of the first battery pack 14A, and the opposite side (Y) of the switch S1 is connected between the positive (+) terminal of the battery module 44 of the second battery pack 14B and the switch SB1. In addition, one side (Y) of the switch S2 is connected between the switches S1 from the side X, and the opposite side (Z) of the switch S2 is connected between the positive (+) terminal of the battery module 44 of the second battery pack 14B and the switch SB1. Therefore, the switches S1 and S2 disposed between the first battery pack 14A and the second battery pack 14B are connected in series with each other, i.e., arranged in series. Thus, these switches S1 and S2 can cooperate to provide switching function redundancy to the series path between the first battery pack 14A and the second battery pack 14B. In some configurations, the contactor switch S1 is integrated with / completely positioned within the first battery pack 14A, and the contactor switch S2 is integrated with / completely positioned within the second battery pack 14B.

[0100] When switch S1 and / or switch S2 are open and switches SA1 and SB1 are closed, the first battery pack 14A and the second battery pack 14B are electrically connected in parallel. When switches S1 and S2 are closed and switches SA2 and SB1 are open, the first battery pack 14A and the second battery pack 14B are electrically connected in series. Therefore, when arranged in series, the battery pack voltage V B The voltage level is increased relative to that in a parallel arrangement, and therefore the battery system 12 is able to utilize a higher charging voltage.

[0101] Various switches SA1, SA2, SA3, PCA, SB1, SB2, SB3, PCB, S1, S2, OB1, OB2 may be used to control the battery system 12, such as Figure 2 For example, in the first battery pack 14A as viewed from left to right, switches PCA, SA1, and SA3 may be connected to the positive bus rail 16 + and the positive (+) terminal of the battery module 44 of the first battery pack 14A. The switch SA2 may be connected to the negative bus rail 16 -and the negative (-) terminal of the battery module 44 of the first battery pack 14A. Similarly, in the second battery pack 14B, when viewed from left to right again, switches SB3, SB1, and PCB can be used between the positive bus rail 16 + and the positive (+) terminal of the battery module 44 of the second battery pack 14B, while switches SB2 can be used between the negative bus rail 16 - and the negative (-) terminal of the battery module 44 of the second battery pack 14B.

[0102] In the labeling nomenclature used herein, "S" generally refers to "switch" regardless of its construction, and "1", "2", and "3" are used as nominal switch identifiers. "A" generally refers to the characteristics of the first battery pack 14A, and "B" generally refers to the characteristics of the second battery pack 14B. "PC" refers to "pre-charge", where two pre-charge switches PCA and PCB are used to ensure that the voltage bus is fully charged before disconnecting the pre-charge switches PCA and PCB. It will be appreciated that each pre-charge switch PCA and PCB is connected in series with a pre-charge resistor to help limit the inrush current when the pre-charge switches PCA and PCB are initially closed.

[0103] The battery system 12 can be controlled by the controller 40 using switching control logic (such as illustrated in the logic table of Figure 3 ) to perform charging of the first battery pack 14A and the second battery pack 14B and / or propulsion of the mobile platform 10. Figure 3 The far left column of [] indicates the various propulsion and charging modes of the battery packs 14A, 14B, and Figure 3 the top row of [] identifies the various switches SA1, SA2, SA3, SB1, SB2, SB3, S1, S2, OB1, OB2 corresponding to Figure 2 . As described below, the disclosed configuration of the battery system 12 enables the controller 40 to select one or more parallel charging modes and series charging modes, including, for example, 800V DCFC, 400V DCFC, 400V 22 kilowatts (kW) charging (Chrg), 400V 11 kW charging. Additionally, the disclosed configuration of the battery system 12 enables the controller 40 to select one or more propulsion modes, including the propulsion system active (PSA) mode. The logic table is filled with the corresponding mode-specific switch open / closed states, where "O" corresponds to the open switch state in which an open circuit is formed (i.e., the switch does not conduct electricity), and "X" corresponds to the closed switch state in which the switch conducts electricity. "X n”Corresponds to the following situation in the logic table: One of the switches is closed, but not both switches. For example, the 800V DCFC charging mode in the logic table identifies switches SA1 and SA2 as X1, which means that SA1 or SA2 is closed, but not both. Figure 3 The far - right column identifies the total number of switches closed for each of the charging and propulsion modes.

[0104] As mentioned above, the controller 40 communicates with switches SA1, SA2, SA3, PCA, SB1, SB2, SB3, PCB, S1, S2, OB1, OB2, and the switches include the first contactor switch S1 and the second contactor switch S2. Generally, the controller 40 determines whether to open or close the first contactor switch S1 and the second contactor switch S2 depending on whether the first battery pack 14A and the second battery pack 14B are being charged in the high - voltage mode or the low - voltage mode. Thus, the controller 40 signals the first contactor switch S1 and the second contactor switch S2 to selectively open and close depending on whether the battery packs 14A, 14B are in the high - voltage mode or the low - voltage mode.

[0105] When in the high - voltage mode, both the first contactor switch S1 and the second contactor switch S2 are closed, and this high - voltage mode electrically connects the first battery pack 14A and the second battery pack 14B in a series arrangement. The high - voltage mode can be when the battery packs 14A, 14B are combined in series to reach 600V or higher. During charging when in series arrangement, one of the battery packs 14A, 14B is charged at a time, and the other of the battery packs 14A, 14B will supply power to the auxiliary power module. The controller 40 determines which of the battery packs 14A, 14B will be charged and which one will supply power to the auxiliary power module 34. That is, during charging, the two battery packs 14A, 14B will not both supply power to the auxiliary power module simultaneously.

[0106] When in the low-voltage mode, at least one of the first contactor switch S1 and the second contactor switch S2 is opened, and this low-voltage mode electrically connects the first battery pack 14A and the second battery pack 14B in a parallel arrangement. For example, when it is mentioned that at least one of the first contactor switch S1 and the second contactor switch S2 is opened when in the low-voltage mode, the first contactor switch S1 is opened, or the second contactor switch S2 is opened, or both the first contactor switch S1 and the second contactor switch S2 are opened. The low-voltage mode can be when the battery packs 14A, 14B are in parallel to reach 300V - 500V. During charging when in a parallel arrangement, when both of the two battery packs 14A, 14B are being charged, both of the two battery packs 14A, 14B will supply power to the auxiliary power module 34. That is, during charging, both of the two battery packs 14A, 14B will supply power to the auxiliary power module simultaneously.

[0107] Therefore, at least one of the first battery pack 14A and the second battery pack 14B operates to supply power to the auxiliary power module 34 when at least one of the first battery pack 14A and the second battery pack 14B is being charged, regardless of whether the first battery pack 14A and the second battery pack 14B are in the high-voltage mode or the low-voltage mode. That is, in some charging operations, the first battery pack 14A can supply power to the auxiliary power module 34 when the second battery pack 14B is being charged, the second battery pack 14B can supply power to the auxiliary power module 34 when the first battery pack 14A is being charged, or when both the first battery pack 14A and the second battery pack 14B are being charged, both the first battery pack 14A and the second battery pack can supply power to the auxiliary power module 34. Simply put, the controller 40 is configured to determine which of the first battery pack 14A and the second battery pack 14B operates to supply power to the auxiliary power module 34 when at least one of the first battery pack 14A and the second battery pack 14B is being charged.

[0108] Collect, monitor, etc. various information to determine which of the battery packs 14A, 14B will be charged when at least one of the battery packs 14A, 14B supplies power to the auxiliary power module 34, and some of these situations will be discussed below. Depending on whether the battery packs 14A, 14B are in the high-voltage mode (in series arrangement) or the low-voltage mode (in parallel arrangement) will determine whether one or both of the battery packs 14A, 14B will supply power to the auxiliary power module 34, as detailed below.

[0109] During the low voltage mode, signal at least one of the first contactor switch S1 and the second contactor switch S2 to open so that the first battery pack 14A and the second battery pack 14B are arranged in parallel, wherein when both the first battery pack 14A and the second battery pack 14B are being charged, both the first battery pack 14A and the second battery pack 14B supply power to the auxiliary power module 34. Thus, when both the first battery pack 14A and the second battery pack 14B are being charged simultaneously, the two battery packs 14A, 14B supply power to the auxiliary power module 34 simultaneously. Again, as mentioned above, the first contactor switch S1 can be opened, the second contactor switch S2 can be opened, or both the first contactor switch S1 and the second contactor switch S2 can be opened in the parallel arrangement.

[0110] During the high voltage mode, signal the first contactor switch S1 and the second contactor switch S2 to close so that the first battery pack 14A and the second battery pack 14B are arranged in series, wherein one of the first battery pack 14A and the second battery pack 14B supplies power to the auxiliary power module 34, and the other of the first battery pack 14A and the second battery pack 14B is being charged. In this configuration, one of the battery packs 14A, 14B supplies power while the other of the battery packs 14A, 14B is being charged. Thus, when arranged in series, the two battery packs 14A, 14B do not both perform the same operation (i.e., charging and power supply) simultaneously.

[0111] Generally, when arranged in series, the controller 40 determines when to transition charging between the first battery pack 14A and the second battery pack 14B, and additionally determines when to transition to supplying power to operate the auxiliary power module 34. For example, in some configurations, when arranged in series, the controller 40 determines that the first battery pack 14A will be charged while the second battery pack 14B supplies power to the auxiliary power module 34. When the first battery pack 14A and the second battery pack 14B are arranged in series, when the controller 40 determines that it is time to transition, charging transitions from the first battery pack 14A to the second battery pack 14B, and the power supply transitions from being supplied by the second battery pack 14B to being supplied by the first battery pack 14A to operate the auxiliary power module 34. When the first battery pack 14A and the second battery pack 14B are arranged in parallel, no charging transition occurs. Additionally, when the first battery pack 14A and the second battery pack 14B are arranged in parallel, no power supply transition occurs.

[0112] When arranged in series, the controller 40 uses various information to determine when to transition between the battery packs 14A, 14B, and examples of the information and transitions are discussed below.

[0113] Determine the average energy difference (of the first battery pack 14A) based on the maximum available energy level of the first battery pack 14A and the remaining energy level to full charge of the first battery pack 14A (via the controller 40). Determine the average energy difference (of the second battery pack 14B) based on the maximum available energy level of the second battery pack 14B and the remaining energy level to full charge of the second battery pack 14B (via the controller 40). Thus, the controller 40 is configured to: determine the maximum available energy level of each of the first battery pack 14A and the second battery pack 14B and the remaining energy level to full charge of the first battery pack 14A and the second battery pack 14B; and use this information to determine the average energy difference of each of the battery packs 14A, 14B. The average energy difference of the first battery pack 14A and the average energy difference of the second battery pack 14B assume that the state of charge and voltage of the first battery pack 14A are similar to or equal to the state of charge and voltage of the second battery pack 14B.

[0114] Generally, the controller 40 is configured to: select one of the first battery pack 14A and the second battery pack 14B to supply power to the auxiliary power module 34 based on a comparison of the maximum available energy level and the remaining energy level to full charge of the first battery pack 14A with the maximum available energy level and the remaining energy level to full charge of the second battery pack 14B. Thus, the controller 40 selects one of the first battery pack 14A and the second battery pack 14B to supply power to the auxiliary power module 34 based on a comparison of the average energy difference of the first battery pack 14A with the average energy difference of the second battery pack 14B. Select one of the first battery pack 14A and the second battery pack 14B to supply power to the auxiliary power module 34 based on the smaller average energy difference (via the controller 40). For example, if the average energy difference of the first battery pack 14A is less than the average energy difference of the second battery pack 14B, the first battery pack 14A is selected to power the accessory because the degree to which the accessory load affects the charging rate of the first battery pack 14A will be less than the degree to which it affects the charging rate of the second battery pack 14B. The average energy difference of the first battery pack 14A and the second battery pack 14B can be used to determine which of the battery packs 14A, 14B supports the accessory load for a series arrangement.

[0115] When the remaining energy levels to full charge of the first battery pack 14A and the second battery pack 14B are the same or equal, the battery pack 14A, 14B powering the accessory should switch to the other battery pack 14A, 14B, and then repeat back and forth at a faster rate to ensure that the charging rates remain balanced. Generally, in such a case, the battery packs 14A, 14B should be switched back and forth using a calculation of dividing the remaining charge time by two to ensure that the charging rates remain balanced. This calculation also assumes that the state of charge and voltage of the first battery pack 14A are similar to or equal to the state of charge and voltage of the second battery pack 14B.

[0116] For example, when the first contactor switch S1 and the second contactor switch S2 are closed, the first battery pack 14A can be charged in the high voltage mode, and when in the high voltage mode, the second battery pack 14B can supply power to the auxiliary power module 34. In some configurations, when in the high voltage mode, charging transitions from the first battery pack 14A to the second battery pack 14B, and the power supply transitions from the second battery pack 14B to the first battery pack 14A to operate the auxiliary power module 34, which is based on the average energy difference aggregated from the maximum available energy level of the first battery pack 14A and the remaining energy level to full charge, and the average energy difference aggregated from the maximum available energy level of the second battery pack 14B and the remaining energy level to full charge.

[0117] The controller 40 can monitor various parameters to determine when to transition between the battery packs 14A, 14B. Thus, the average energy difference can be monitored (via the controller 40) based on the maximum available energy level of the first battery pack 14A and the remaining energy level to full charge, and the average energy difference can be monitored (via the controller 40) based on the maximum available energy level of the second battery pack 14B and the remaining energy level to full charge to determine whether to change the power supply from one of the first battery pack 14A and the second battery pack 14B to the auxiliary power module 34 to the power supply from the other of the first battery pack 14A and the second battery pack 14B to the auxiliary power module 34. Additionally, the remaining charge time of the first battery pack 14A and the second battery pack 14B can be monitored (via the controller 40) to determine whether to change the power supply from one of the first battery pack 14A and the second battery pack 14B to the auxiliary power module 34 to the power supply from the other of the first battery pack 14A and the second battery pack 14B to the auxiliary power module 34. Further, the charge state of the first battery pack 14A and the charge state of the second battery pack 14B can be monitored (via the controller 40) to determine whether to change the power supply from one of the first battery pack 14A and the second battery pack 14B to the auxiliary power module 34 to the power supply from the other of the first battery pack 14A and the second battery pack 14B to the auxiliary power module 34.

[0118] Typically, charging is switched from one of the battery packs 14A, 14B to the other of the battery packs 14A, 14B to complete charging of or fully charge the battery packs 14A, 14B, and correspondingly, the power used to operate the auxiliary power module 34 is switched to the other of the battery packs 14A, 14B. The controller 40 is configured to switch charging and power supply between the battery packs 14A, 14B. Thus, for example, when in the high voltage mode, charging is switched from the first battery pack 14A to the second battery pack 14B, and the power supply from the second battery pack 14B to the auxiliary power module 34 is switched to the power supply from the first battery pack 14A to the auxiliary power module 34.

[0119] During this transition, as Figure 4 best shown via the aligned graphs, the charge state graph illustrates that the charge states of the first battery pack 14A and the second battery pack 14B simultaneously tend towards horizontal, such that the current supplied to charge one of the battery packs 14A, 14B decreases according to the station current graph. Accordingly, the controller 40 signals the off-vehicle DCFC station 18 to decrease the current supplied to the battery pack 14A, 14B being charged according to the station current graph. The y-axis of the charge state graph may represent the percentage of the charge level of the batteries 14A, 14B, and the x-axis of the charge state graph may represent time. Additionally, the y-axis of the station current graph may represent current, and the x-axis of the station current graph may represent time.

[0120] In one example, when the second battery pack 14B is being charged, during the power transition between the first battery pack 14A and the second battery pack 14B, a decrease in the current of the second battery pack 14B is signaled. In another example, when the first battery pack 14A is being charged, during the power transition between the first battery pack 14A and the second battery pack 14B, a decrease in the current of the first battery pack 14A is signaled. For example, in Figure 4 with reference to the station current graph, the first battery pack 14A is initially selected to power the accessory and thus power the auxiliary power module 34, and the second battery pack 14B is being charged at that time. When the transition occurs in Figure 4 the current to the second battery pack 14B is decreased to switch the charging to the first battery pack 14A, and the current used to power the accessory is decreased to switch the power supply from the first battery pack 14A to the accessory to the power supply from the second battery pack 14B to the accessory. Now, referring to the charge state graph in Figure 4 the charge state of the second battery pack 14B is greater than the charge state of the first battery pack 14A, but the charge state of each of the battery packs 14A, 14B tends towards horizontal during this transition period. Once the transition is complete, as in Figure 4As shown in the station charge of the "station charge", the first battery pack 14A is charged, while the second battery pack 14B powers the accessories, that is, powers the auxiliary power module 34. The decrease in current that appears in the station current chart can be the station minimum current and margin (as a non-limiting example, the current drops to 10 amperes) to avoid interruption of the charging session at the off-vehicle DCFC station 18. By reducing the current during the transition between the battery packs 14A and 14B, this provides a tolerance for low-voltage or 12V accessories. Thus, reducing the current during the transition protects the low-voltage or 12V accessories and also prevents interruption of power to one or more of the switches SA1, SA2, SA3, PCA, SB1, SB2, SB3, PCB, S1, S2, OB1, OB2. It will be appreciated that if there is a high confidence in the low-voltage or 12V accessories, the transition between the first battery pack 14A and the second battery pack 14B can occur at full current (i.e., the current does not drop to the station minimum).

[0121] Figure 5 A flowchart depicting a method 100 of using the battery system 12 is shown. The controller 40 monitors, collects data, makes decisions, and opens / closes various switches SA1, SA2, SA3, PCA, SB1, SB2, SB3, PCB, S1, S2, OB1, OB2 depending on the desired propulsion mode and / or charging mode. Refer to Figure 5 , the method 100 starts with the controller 40 starting charging at block 102. During this method 100, charging can occur for both the first battery pack 14A and the second battery pack 14B in a parallel arrangement, or for one battery pack 14A, 14B at a time in a series arrangement. Additionally, the charging can be switched from a series arrangement to a parallel arrangement at some point in the method 100, as discussed further below. Generally, Figure 5 the method 100 starts at block 102, where the battery packs 14A, 14B are in a series arrangement.

[0122] At block 104, the average energy difference can be used to determine which of the battery packs 14A, 14B will power the accessories. Specifically, at block 104, the controller 40 compares the average energy difference of the first battery pack 14A (which can be determined by subtracting the remaining energy level to full charge from the maximum available energy) with the average energy difference of the second battery pack 14B (which can be determined by subtracting the remaining energy level to full charge from the maximum available energy). Continuing at block 104, via the controller 40, power to the accessories is disconnected from the battery pack 14A, 14B with the higher average energy difference (i.e., the battery pack 14A, 14B that needs more charging).

[0123] Next, at block 106, the controller 40 connects the battery packs 14A, 14B having a lower average energy difference (i.e., the minimum energy difference) to power the accessory at 300V - 500V power. At block 108, the controller 40 collects and / or determines the voltage difference, charge state difference, and elapsed time of the first battery pack 14A and the second battery pack 14B, and uses this data to determine whether to switch or transition the accessory to another battery pack 14A, 14B.

[0124] At block 110, the currents in the parallel arrangement and the series arrangement are compared (via the controller 40). Depending on the result of the comparison at block 110, the method 100 will continue to have the battery packs 14A, 14B in a series arrangement or will switch to having the battery packs 14A, 14B in a parallel arrangement to complete the charging.

[0125] At block 112, if the current in the parallel arrangement is greater than the current in the series arrangement, the charging of the first battery pack 14A and the second battery pack 14B is completed in a parallel arrangement. Thus, at block 112, the battery packs 14A, 14B are switched from a series arrangement to a parallel arrangement.

[0126] Again, as mentioned above, at block 110, the currents in the parallel arrangement and the series arrangement are compared (via the controller 40). If the current in the parallel arrangement is less than the current in the series arrangement, the battery packs 14A, 14B continue in a series arrangement to block 114. Generally, in some configurations, if the current in the parallel arrangement is less than the current in the series arrangement, the charging may be disconnected from one of the first battery pack 14A and the second battery pack 14B, and then the other of the first battery pack 14A and the second battery pack 14B starts charging (via the controller 40). In other words, the controller 40 is configured to: if the current in the parallel arrangement is less than the current in the series arrangement, disconnect the charging of one of the first battery pack 14A and the second battery pack 14B, and then select the other of the first battery pack 14A and the second battery pack 14B for charging so as to charge while also transitioning the power supply to the auxiliary power module 34 from the first battery pack 14A and the second battery pack 14B to the other of the first battery pack 14A and the second battery pack 14B.

[0127] If the current in the series arrangement is less than the current in the parallel arrangement, the controller 40 may consider additional information at block 114. At block 114, the controller 40 collects and / or determines voltage differences, state-of-charge differences, average energy differences, and compares the actual values with the theoretical data. Continuing at block 114, the determined voltage differences for each of the battery packs 14A, 14B are compared with the theoretical voltage differences, the determined state-of-charge differences are compared with the theoretical state of charge, and the determined average energy differences are compared with the theoretical energy differences. Continuing at block 114, if the theoretical data is greater than the actual data, method 100 returns to block 108.

[0128] If the determined voltage difference for each of the battery packs 14A, 14B is greater than the theoretical voltage difference, the determined state-of-charge difference is greater than the theoretical state of charge, and the determined average energy difference is greater than or equal to the theoretical energy difference, then method 100 proceeds to block 116. At block 116, the battery packs 14A, 14B powering the accessory are disconnected via the controller 40.

[0129] At block 118, the controller 40 confirms that the battery packs 14A, 14B have been disconnected at block 116. If the battery packs 14A, 14B have not been disconnected, method 100 returns to block 116 to disconnect the battery packs 14A, 14B. Once the controller 40 confirms that the desired battery packs 14A, 14B are disconnected, method 100 proceeds to block 120. At block 120, the other of the first battery pack 14A and the second battery pack 14B begins to power the accessory (i.e., the auxiliary power module 34). Then, method 100 returns to block 108 to repeat the various blocks until each of the battery packs 14A, 14B is fully charged.

[0130] It will be appreciated that the order or sequence of performing method 100 as identified in the flowchart of Figure 5 is for illustrative purposes, and other orders or sequences are within the scope of this teaching. It will also be appreciated that method 100 may include other features not specifically identified in the flowchart of Figure 5 .

[0131] Although the best mode and other configurations for implementing the present disclosure have been described in detail, those skilled in the art of the field to which this disclosure pertains will recognize various alternative designs and configurations for practicing the present disclosure that are within the scope of the appended claims. Additionally, the characteristics of the configurations shown in the figures or mentioned in this description need not be understood as independent configurations from one another. Instead, it is possible that each characteristic described in one example of a configuration can be combined with one or more other desired characteristics from other configurations, resulting in other configurations that are not described in words or with reference to the figures. Accordingly, such other configurations fall within the framework of the scope of the appended claims.

Claims

1. A method of using a battery system, the battery system comprising: Positive and negative DC voltage bus rails; A first battery pack and a second battery pack, which are connected to the positive and negative DC voltage bus rails; An auxiliary power module, which is configured to support an auxiliary load; A first contactor switch, which is connected between the first battery pack and the second battery pack; And a second contactor switch, which is in series with the first contactor switch between the first battery pack and the second battery pack, the method comprising: Determining to open or close the first contactor switch and the second contactor switch via a controller depending on whether the first battery pack and the second battery pack are being charged in a high voltage mode or a low voltage mode; Wherein, when in the high voltage mode, both the first contactor switch and the second contactor switch are closed, and the high voltage mode electrically connects the first battery pack and the second battery pack in a series arrangement; Wherein, when in the low voltage mode, at least one of the first contactor switch and the second contactor switch is open, and the low voltage mode electrically connects the first battery pack and the second battery pack in a parallel arrangement; and Operating at least one of the first battery pack and the second battery pack to power the auxiliary power module when charging at least one of the first battery pack and the second battery pack, regardless of whether the first battery pack and the second battery pack are in the high voltage mode or the low voltage mode; Determining an average energy difference based on the maximum available energy level of the first battery pack and the remaining energy level to full charge, and determining an average energy difference based on the maximum available energy level of the second battery pack and the remaining energy level to full charge; and Selecting one of the first battery pack and the second battery pack to supply power to the auxiliary power module based on the smaller average energy difference; And when the remaining energy levels to full charge of the first battery pack and the second battery pack are the same or equal, the battery pack supplying power to the auxiliary power module changes to the other battery pack, and then repeats back and forth at a faster rate to ensure that the charging rates remain balanced; Comparing the current in the parallel arrangement and the current in the series arrangement; and If the current in the parallel arrangement is greater than the current in the series arrangement, charging the first battery pack and the second battery pack is completed in the parallel arrangement; Comparing the current in the parallel arrangement and the current in the series arrangement; and If the current in the parallel arrangement is less than the current in the series arrangement, disconnect the charging of one of the first battery pack and the second battery pack, and then charge the other of the first battery pack and the second battery pack.

2. The method according to claim 1, further comprising: When in the high voltage mode, change the charging from the first battery pack to the second battery pack, and change the power supply from the second battery pack to supply from the first battery pack to operate the auxiliary power module.

3. The method according to claim 2, further comprising: During the power transition between the first battery pack and the second battery pack, signal a decrease in the current of the second battery pack.

4. The method according to claim 2, wherein, When in the high-voltage mode, the charging is switched from the first battery pack to the second battery pack, and the power supply is switched from the second battery pack to the first battery pack to operate the auxiliary power module, based on the average energy difference aggregated from the maximum available energy level of the first battery pack and the remaining energy level to full charge, and the average energy difference aggregated from the maximum available energy level of the second battery pack and the remaining energy level to full charge.

5. The method according to claim 2, further comprising: The average energy difference is monitored based on the maximum available energy level of the first battery pack and the remaining energy level to full charge, and the average energy difference is monitored based on the maximum available energy level of the second battery pack and the remaining energy level to full charge, to determine whether to switch the power supply from one of the first battery pack and the second battery pack to the auxiliary power module to the power supply from the other of the first battery pack and the second battery pack to the auxiliary power module.

6. The method according to claim 5, further comprising: The remaining charging time of the first battery pack and the second battery pack is monitored to determine whether to switch the power supply from one of the first battery pack and the second battery pack to the auxiliary power module to the power supply from the other of the first battery pack and the second battery pack to the auxiliary power module.

7. The method according to claim 6, further comprising: The charge state of the first battery pack and the charge state of the second battery pack are monitored to determine whether to switch the power supply from one of the first battery pack and the second battery pack to the auxiliary power module to the power supply from the other of the first battery pack and the second battery pack to the auxiliary power module.

8. The method according to claim 1, further comprising: During the low-voltage mode, at least one of the first contact switch and the second contact switch is signaled to open, such that the first battery pack and the second battery pack are in the parallel arrangement, in which both the first battery pack and the second battery pack supply power to the auxiliary power module when both the first battery pack and the second battery pack are being charged.

9. The method according to claim 1, further comprising: During the high-voltage mode, the first contact switch and the second contact switch are signaled to close, such that the first battery pack and the second battery pack are in the series arrangement, in which one of the first battery pack and the second battery pack supplies power to the auxiliary power module and the other of the first battery pack and the second battery pack is being charged.

10. The method according to claim 1: It further includes: When the first battery pack and the second battery pack are in the series arrangement, the charging is switched from the first battery pack to the second battery pack, and the power supply is switched from the second battery pack to the first battery pack to operate the auxiliary power module; and wherein when the first battery pack and the second battery pack are in the parallel arrangement, the switching of the charging does not occur.

11. A battery system, comprising: Positive and negative direct current voltage bus rails; A first battery pack and a second battery pack, each connected to the positive and negative direct current voltage bus rails; An auxiliary power module configured to support an auxiliary load and electrically connected to at least one of the first battery pack and the second battery pack; A first contact switch connected between the first battery pack and the second battery pack; A second contact switch connected in series with the first contact switch between the first battery pack and the second battery pack; A controller in communication with the first contact switch and the second contact switch to selectively open and close the first contact switch and the second contact switch depending on whether the first battery pack and the second battery pack are in a high voltage mode or a low voltage mode; Wherein when in the high voltage mode, both the first contact switch and the second contact switch are closed, and the high voltage mode electrically connects the first battery pack and the second battery pack in a series arrangement; Wherein when in the low voltage mode, at least one of the first contact switch and the second contact switch is open, and the low voltage mode electrically connects the first battery pack and the second battery pack in a parallel arrangement; and Wherein the controller is configured to: determine which of the first battery pack and the second battery pack is operating to supply power to the auxiliary power module when at least one of the first battery pack and the second battery pack is being charged, regardless of whether the first battery pack and the second battery pack are in the high voltage mode or the low voltage mode; Wherein the controller is configured to: determine an average energy difference based on the maximum available energy level of the first battery pack and the remaining energy level to full charge, and determine an average energy difference based on the maximum available energy level of the second battery pack and the remaining energy level to full charge; Wherein the controller selects one of the first battery pack and the second battery pack to supply power to the auxiliary power module based on the smaller average energy difference, and when the remaining energy levels to full charge of the first battery pack and the second battery pack are the same or equal, the battery pack powering the auxiliary power module changes to the other battery pack and then repeats back and forth at a faster rate to ensure that the charging rates remain balanced; Wherein the controller is configured to compare the current in the parallel arrangement and the current in the series arrangement, and the controller is configured to: if the current in the parallel arrangement is greater than the current in the series arrangement, allow the first battery pack and the second battery pack to be charged in the parallel arrangement; and Wherein the controller is configured to compare the current in the parallel arrangement and the current in the series arrangement, and the controller is configured to: if the current in the parallel arrangement is less than the current in the series arrangement, disconnect the charging of one of the first battery pack and the second battery pack and then select the other of the first battery pack and the second battery pack for charging.

12. The system according to claim 11, wherein, The controller is configured to: during the low voltage mode, signal at least one of the first contactor switch and the second contactor switch to open, such that the first battery pack and the second battery pack are in the parallel arrangement, in which both the first battery pack and the second battery pack supply power to the auxiliary power module when both the first battery pack and the second battery pack are being charged.

13. The system according to claim 11, wherein The controller is configured to: when in the high voltage mode, transfer charging from the first battery pack to the second battery pack, and transfer power supply from the second battery pack to the first battery pack to operate the auxiliary power module.

14. The system according to claim 13, wherein, During the power transfer between the first battery pack and the second battery pack, the controller signals a decrease in the current of the second battery pack.

15. The system according to claim 13: Among them, The controller is configured to: monitor an average energy difference based on the maximum available energy level of the first battery pack and the remaining energy level to full charge, and monitor an average energy difference based on the maximum available energy level of the second battery pack and the remaining energy level to full charge, to determine whether to transfer power supply to the auxiliary power module from one of the first battery pack and the second battery pack to the other of the first battery pack and the second battery pack; wherein the controller is configured to: monitor the remaining charge time of the first battery pack and the second battery pack to determine whether to transfer power supply to the auxiliary power module from one of the first battery pack and the second battery pack to the other of the first battery pack and the second battery pack; wherein the controller is configured to: monitor the charge state of the first battery pack and the charge state of the second battery pack to determine whether to transfer power supply to the auxiliary power module from one of the first battery pack and the second battery pack to the other of the first battery pack and the second battery pack.

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