DC-DC parallelization control algorithm

Abstract

To provide a charge balancing energy storage system.SOLUTION: An energy storage system (EMS) 210 for mobile and stationary applications includes multiple battery packs connected in parallel via bidirectional DC-DC converters and managed by centralized or de-centralized control. Each pack comprises one or more electrochemical storage elements, and the EMS regulates current flow based on system data indicating state of charge (SOC), state of health (SOH), temperature and chemistry, performs active balancing by adjusting current commands to equalize SOC between packs, and isolates faulty or degraded modules if necessary. The architecture supports heterogeneous battery types, modular scalability, and fault-tolerant operation, enabling safe and efficient control of energy storage resources in a variety of electrified transportation and stationary power environments.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This application relates generally to energy storage systems, and more particularly to charge balancing energy storage systems. [Background technology]

[0002] Batteries are becoming widely adopted in the transportation sector, particularly in applications such as electric vehicles, hybrid electric vehicles, stationary energy storage systems, microgrids, and other devices and equipment that are at least partially powered by energy storage. Electrical circuits include two types of current: direct current (DC) and alternating current (AC). In certain electrical systems, energy storage components may be connected to a common DC bus through a dedicated DC-DC converter, which is configured to "step up" or "step down" the voltage to match the common DC bus voltage. In other electrical systems, a dedicated DC-AC inverter is required to properly connect the energy storage components to the common AC bus.

[0003] As demand for electric vehicles increases, so does the desire for improved driving range, power redundancy, peak shaving, and other desirable operating characteristics. Certain applications further require the combination of different energy storage technologies, battery technologies, chemistries, manufacturers, and / or health states (i.e., mixing old and new batteries as a result of system maintenance) within the same system. Summary of the Invention

[0004] The following summary provides a high-level overview of selected aspects of the present disclosure and is not intended to represent an exhaustive list of all features or embodiments. Rather, this summary serves to highlight certain inventive principles and advantages associated with a DC-DC paralleling control algorithm and related components configured for use in a charge-balancing energy storage system. Disclosed features include one or more batteries connected in parallel and a control interface that contributes to enhanced charge balancing and improved operational management.

[0005] Additional features, aspects, and embodiments of the present disclosure are described in more detail below with reference to illustrative examples and implementations. The following detailed description is intended to provide further explanation and context regarding the structure, function, and integration of the disclosed battery system, including various configurations of battery circuits, interfaces, control logic, and system data processing. While specific examples are described to facilitate understanding, the scope of the present disclosure is not limited to the specific embodiments described, but may encompass other variations and modifications consistent with the inventive principles described herein.

[0006] In Example 1, a battery system for distributing current among a plurality of batteries is provided. The battery system includes a plurality of battery circuits connected in parallel. Each battery circuit in the plurality of battery circuits includes one or more batteries connected in series and / or parallel. Each battery in the one or more batteries is configured to store energy for use in the battery system. Each battery circuit further includes an interface including a DC / DC converter operably connected to the one or more batteries. The interface is configured to control current flow to one or more batteries in a respective battery circuit during operation of the battery system based on system data and to facilitate balancing of each of the one or more batteries in the battery system based on operating parameters included in the system data. The operating parameters may include at least one of current, state of charge (SOC), and state of health (SOH).

[0007] In Example 2, in addition to Example 1, the system data includes parameters corresponding to a state of charge and a state of health of each battery in the one or more batteries.

[0008] In Example 3, as in Example 2, the system data further includes parameters corresponding to at least one of a chemistry and a temperature of each battery in the one or more batteries.

[0009] In Example 4, in addition to Example 1, the interface is further configured to control current flow to the one or more batteries based on system data such that the one or more batteries are designed to operate independently from other batteries in the battery system.

[0010] In Example 5, in addition to Example 1, the battery system further comprises a controller operably connected to each interface, the controller configured to receive and process system data from the plurality of battery circuits.

[0011] In Example 6, in addition to Example 5, the controller is further configured to distribute current within the battery system to maintain a state of charge of each of the one or more batteries within a sufficiently small vicinity of an average state of charge of the battery system.

[0012] In Example 7, as in Example 6, the controller is further configured to distribute the current by biasing the amount of current commanded by a given battery circuit within the plurality of battery circuits until an operating parameter of each of the one or more batteries is within a sufficiently small neighborhood of an average of an operating parameter of the battery system.

[0013] In Example 8, further to example 5, the plurality of battery circuits includes a first battery circuit and a second battery circuit. The first battery circuit has a first battery having a first chemistry, and the second battery circuit has a second battery having a second chemistry different from the first chemistry. The controller is further configured to receive an indication that the first chemistry is different from the second chemistry and to distribute the current differently based on the chemistry of each battery circuit.

[0014] In Example 9, in addition to Example 5, the controller is further configured to receive an indication that at least one of the one or more batteries has failed, and in response, exclude the failed at least one battery from the balancing.

[0015] In Example 10, further to Example 9, the at least one battery is determined to have failed when the at least one battery has reached the end of its life.

[0016] In Example 11, in addition to Example 5, the controller is further configured to prevent charging of any of the plurality of batteries when the battery system is providing power.

[0017] In Example 12, in addition to Example 5, the controller is further configured to prevent discharging any of the plurality of batteries when the battery system is receiving power.

[0018] In Example 13, further to Example 1, the battery system is incorporated into an integrated power system, and in the integrated power system, the plurality of battery circuits comprises three or more battery circuits.

[0019] Example 14 provides a method of operating the battery system of Example 1. The method includes receiving an indication of a fault in the battery system, using control logic to control current flow in a battery experiencing the fault to isolate the battery from operation, and using the control logic to continue operation of the battery system with a non-heresy battery while minimizing a period of time during which batteries are both charging and discharging within the battery system.

[0020] In Example 15, in addition to Example 14, the method further comprises controlling current flow in the battery based on an operating parameter.

[0021] In Example 16, in addition to Example 15, the operating parameter corresponds to at least one of a current flow in the battery in a corresponding one of a plurality of parallel connected battery circuits, a state of charge of the battery in the corresponding battery circuit, a state of health of the battery in the corresponding battery circuit, a current limit of the battery in the corresponding battery circuit, a temperature of the battery in the corresponding battery circuit, and a chemistry of the battery in the corresponding battery circuit.

[0022] In Example 17, a non-transitory computer-readable medium storing a set of instructions for operating the battery system of Example 1 is provided. The set of instructions comprises one or more instructions that, when executed by one or more processors of a device, cause the device to receive an indication of a degradation or failure in a battery system based on system data corresponding to (a) a current flow in a battery in one of the plurality of battery circuits and (b) a state of charge of the battery in the battery circuit, use control logic to control the current flow in the battery to isolate from operation a battery experiencing a failure, and use control logic to continue operation of the battery system with a non-miserly battery while minimizing a period of time during which batteries are both charging and discharging within the battery system.

[0023] In Example 18, further to Example 17, the indication of degradation or failure is based on an imbalance of the system data relative to a measure of central tendency of the system data, and the instructions further cause the device to control current flow in the battery within current limits for each of the interconnected battery circuits in the battery system.

[0024] In Example 19, as in Example 18, the system data further corresponds to at least one of a state of health of the battery within a battery circuit, a temperature of the battery within a battery circuit, and a chemistry of the battery within a battery circuit.

[0025] In Example 20, further to the method of Example 17, the battery system is implemented as a kit. The kit includes a plurality of DC / DC converters, each configured to be operably connected to a corresponding battery or battery circuit, and a controller configured to execute the instructions stored on the non-transitory computer-readable medium of Example 17. The kit is configured for incorporation into a vehicle-based or stationary energy storage system to enable distributed current control and fault-tolerant battery operation based on system data. [Brief explanation of the drawings]

[0026] The above and other features and advantages of the present disclosure, and the manner in which they are achieved, will become more apparent, and the invention itself will be better understood, by reference to the following description of embodiments of the invention, taken in conjunction with the accompanying drawings.

[0027] [Figure 1] FIG. 1 is a schematic diagram of an energy storage system for charge balancing.

[0028] [Figure 2A] FIG. 2 is a graphical illustration of the state of charge of the battery in the energy storage system of FIG. 1 during charging.

[0029] [Figure 2B] FIG. 2 is a graphical illustration of the state of charge of the battery in the energy storage system of FIG. 1 during discharge.

[0030] [Figure 3] FIG. 1 is a diagram of control logic for charge balancing.

[0031] [Figure 4] 2 is a flowchart of a method for balancing the system of FIG. 1.

[0032] [Figure 5]FIG. 1 is a schematic diagram of an energy storage system for charge balancing having multiple batteries connected in series in battery circuits, each battery circuit connected in parallel, according to one aspect of the disclosure.

[0033] [Figure 6] FIG. 1 is a schematic diagram of an energy storage system having another type of energy storage.

[0034] [Figure 7A] FIG. 1 is a schematic diagram of an exemplary battery circuit consisting of multiple battery packs connected in series.

[0035] [Figure 7B] FIG. 1 is a schematic diagram of an exemplary battery circuit consisting of multiple battery packs connected in parallel.

[0036] [Figure 7C] FIG. 1 is a schematic diagram of an exemplary battery circuit consisting of multiple battery packs having a combination of both parallel and series connections.

[0037] [Figure 8] 1 is a flow chart of an exemplary integrated power system consisting of an energy storage system, a generator, and an interface that supplies energy to a load.

[0038] Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set forth herein illustrate exemplary embodiments of the present disclosure, and such exemplifications should not be construed as limiting the scope of the present disclosure in any way. DETAILED DESCRIPTION OF THE INVENTION

[0039] Rechargeable batteries can power a variety of systems and solutions. Some examples include hybrid electric vehicles (HEVs), electric vehicles (EVs), generators, storage of renewable energy for later use, and grid energy storage for various purposes (e.g., grid stability, peak shaving, and renewable energy time shifting). In these applications, it is important to measure the cell's state of charge (SOC) and estimate the battery's state of health (SOH). SOC can be defined as the available capacity (in Ah) expressed as a percentage of its rated capacity. SOH represents a measure of a battery's ability to store and deliver electrical energy compared to a new battery.

[0040] Multi-cell batteries, which include multiple individual battery cells, require charge equalization, or "balancing," among each individual battery pack. In other words, charge balancing can be defined as the convergence of the voltage outputs of individual batteries to a system-wide average value. This charge balancing is useful for maximizing the available capacity of the battery and extending its lifespan. For example, voltage differences between cells can cause some cells to overcharge or overdischarge, impairing the battery's state of health (SOH) and, consequently, the overall lifespan of the battery. Therefore, balancing a multi-cell battery is crucial to the safety and reliability of the system.

[0041] SOC and SOH are important factors in managing rechargeable batteries because they describe their performance and help predict their future behavior. Unlike physical quantities (e.g., voltage and temperature), there are no direct methods for measuring SOC and SOH. Therefore, these measurements take into account numerous factors and parameters. For example, SOH measurements may consider age, cycle life (number of charge / discharge cycles), capacity, internal resistance, energy throughput, temperature, self-discharge rate, and voltage. Over time, all batteries age and degrade, resulting in SOH values ​​below their initial level. Batteries with low SOH discharge much faster than "healthier" batteries due to a predictable decline in rated capacity over time. SOC measurements may also consider battery chemistry, voltage, current, capacity, impedance, charge / discharge rate, and temperature. SOC indicates the amount of charge remaining in a battery and is typically expressed as a percentage ranging from 0% to 100%, depending on the charge level. Charge / discharge requirements include voltage, current, and temperature limits, exceeding which can lead to battery damage.

[0042] A battery management system (BMS) monitors and controls the SOC and SOH to ensure safe, effective, and ideal battery operation. Understanding the importance of SOC and SOH is essential in the field of battery management. Accurate SOC estimation is one of the primary tasks of a battery management system, helping to improve system performance and reliability and extend battery life. In fact, accurate battery SOC estimation can avoid unpredictable system interruptions and prevent the battery from being overcharged or overdischarged, which can cause permanent damage to the battery's internal structure. However, because battery discharging and charging involve complex chemical and physical processes, accurately estimating SOC under various operating conditions is not obvious. SOC and SOH monitoring involves measuring the battery's voltage, current, and temperature and using the results to determine the SOC and SOH. SOC is typically calculated by a BMS using the voltage and current flowing into and out of the battery. Meanwhile, SOH is often established based on factors such as the amount of charge / discharge cycles the battery has experienced, its age, and its temperature history.

[0043] This disclosure provides various implementations for intelligent charge balancing of multiple batteries. Such balancing can be performed using multiple circuits, using current and SOC. These circuits include: i) a unique DC-DC converter connected to each battery; and / or ii) a group of batteries connected in series with each other, with the circuits connected in parallel. In some implementations, current limiting can be applied to prevent various components of the design from exceeding their operating capacity, reducing the risk of system failure. Some implementations include reducing periods of both positive and negative current, such as when some batteries are charging and others are discharging. Some implementations include mitigating the impact of a failed or erroneous battery in the balancing scheme by establishing a redundant system that can tolerate the failure of one battery.

[0044] More specifically, multiple batteries connected in parallel with one another may be used in a variety of applications, such as hybrid electric vehicles, stationary energy storage systems, or other applications. Individual batteries within a group of parallel-connected batteries may have different voltages for a variety of reasons. For example, a new replacement battery may have a different voltage than the other batteries in the group. In another example, some batteries may have been used more or less extensively than the other batteries in the group, resulting in different voltages for the individual battery packs. Connecting batteries with a large voltage difference creates a higher voltage potential, and therefore, a larger balancing current is established and flows from the higher-voltage battery to the lower-voltage battery. The higher current poses significant safety concerns for the batteries, their contactors, and / or other equipment or circuitry.

[0045] Implementations of the principles of the present disclosure may include both physical and non-physical implementations. For example, a first physical architecture may have each battery circuit having one battery and its own DC-DC converter. Each battery circuit, and therefore the battery and associated DC-DC converter, are connected in parallel in this manner. There may be a fixed number of battery circuits (i.e., battery and DC-DC converter pairs) in this system. A second physical architecture may have a battery circuit with W, X, Y, or Z batteries connected in series to a single DC-DC converter. Each battery circuit is connected in parallel.

[0046] Focusing on non-physical implementations, exemplary control logic can be employed. For example, the control logic can employ charge balancing based on parameters such as current and SOC to drive toward a system-wide average. Some such control logic can apply current limits. SOH can be an additional input to this control logic. Limits can be imposed based on battery chemistry, capacity, and / or size, as well as battery temperature. In certain embodiments, each battery circuit in the system can charge or discharge at different current levels while converging to a common average SOC for the system. In certain implementations, during normal operation, the system can bias the charge or discharge current by within + / -10% to keep the SOC of all batteries within + / -5%.

[0047] The principles of the present disclosure can also be employed under non-nominal conditions. If the system includes multiple batteries with different chemistries, balancing can prioritize SOC input. The control logic can include logic for identifying and recognizing "faulty" batteries. This aspect can be accomplished through existing fault code detection or algorithms for identifying outlier conditions (SOC, current, etc.) of a particular battery relative to others in the system using known statistical methods. Once a faulty or "outlier" battery is identified, that battery's values ​​can be excluded from the average calculations used for SOC, current, and / or other inputs when determining the average values ​​to which the system will be controlled.

[0048] A battery SOH fault may be triggered when a particular battery reaches the end of its life. SOH decreases as the battery is used, so an SOH fault can be interpreted as the end of a battery's life. However, it is worth noting that a higher SOH does not mean a battery has failed. Current limits are set by the control algorithm to prevent a single battery from drawing too much current. The control algorithm should prevent the current bias from exceeding a certain level (e.g., 20%, 15%, etc.).

[0049] The principles of the present disclosure can also be employed to address energy loss due to simultaneous charging and discharging. Balancing a system by discharging one battery and charging another introduces unnecessary energy loss into the system. Ideally, the devices, systems, and methods disclosed herein aim to improve upon conventional charging and discharging systems and minimize energy loss by preventing (i) any battery from being charged when the entire system is supplying power and / or (ii) any battery from being discharged when the entire system is receiving power. In all cases, the system controller requests power to be supplied to or received from the electrical system. When the electrical system is to supply power, each battery should be discharged or do nothing. No batteries should be charged. When the electrical system is to receive power, each battery should be charged or do nothing. No batteries should be discharged.

[0050] In particular, the principles of the present disclosure are distinguished from those used for active balancing before battery connection. For example, some known systems utilize bypass switches. In contrast, the principles of the present disclosure can be used during operation and therefore do not employ bypass switches. It should be noted that the present disclosure also includes control for non-nominal conditions, such as failures during operation, rather than before connection. For example, the examples disclosed herein can allow for mixing of new and old batteries, such as when a failed battery is replaced with a new one, but the old, still-functioning battery does not need to be replaced.

[0051] Accordingly, the present disclosure provides voltage balancing devices, systems, and methods using multiple DC-DC converters connected to one or more batteries. In embodiments, the DC-DC converters are connected to a single or multiple batteries to form a battery circuit. An exemplary system may include multiple battery circuits connected in parallel to a common DC bus. In particular, employing the principles of the present disclosure can reduce the chance of having unused or underused healthy batteries and reduce the chance of having unbalanced charge / discharge, as mentioned elsewhere herein. There may be a battery DC-DC converter that controls current flow within the battery circuit, thereby facilitating the isolation of each battery in the battery circuit from other battery circuits in the system. Larger systems may include such DC-DC converters operating in concert with other similar DC-DC converters, and optionally known DC-DC converters. For example, such a system may allocate different discharge power to different battery circuits, discharging batteries with higher SOCs more than batteries with lower SOCs until their battery SOCs converge to (or within a tolerance of) the system average SOC, thereby preventing excessive current when those packs are connected to a common DC bus.

[0052] 1-8 illustrate exemplary embodiments and design features of age balancing devices, systems, and methods that use multiple DC-DC converters connected to one or more batteries.

[0053] 1 shows a schematic diagram of an energy storage system for charge balancing. In this embodiment, an energy storage system 10 according to an example of the present disclosure is shown.

[0054] The system 10 generally includes a plurality of batteries 12A-12D and a corresponding plurality of DC-DC converters 14A-14D. Each battery is coupled to a respective DC-DC converter. In other words, the first battery 12A is coupled to the first DC-DC converter 14A, the second battery 12B is coupled to the second DC-DC converter 14B, the third battery 12C is coupled to the third DC-DC converter 14C, and the fourth battery 12D is coupled to the fourth DC-DC converter 14D. All of the DC-DC converters 14A-14D are connected to a system DC bus, which is defined as a common electrical point having a specific, discrete voltage level. The system DC bus is connected to a load or power source 16 to supply or provide power to the load or power source 16. While four batteries 12A-12D are shown in FIG. 1, those skilled in the art should understand that more or fewer batteries may be used for different applications without departing from the scope of the present disclosure. Batteries 12A-12D may store electrical energy using any of a variety of different rechargeable cell technologies, chemistries, and materials. For example, batteries 12A-12D may employ electrode materials and electrolytes such as lead acid, nickel cadmium, nickel metal hydride, lithium ion, or lithium ion polymer. Load or source 16 represents a system powered by batteries 12A-12D, including, but not limited to, an electric machine, an engine, or other type of equipment requiring a particular voltage, current, and power rating.

[0055] As noted above, DC-DC converters 14A-14D may be unique and / or any of a variety of suitable DC-DC converters known to those skilled in the art (e.g., buck converters and buck-boost converters). Some exemplary DC-DC converter topologies that may be employed include buck-boost, half-bridge, full-bridge, and variations thereof. DC-DC converters may use a battery voltage regulator (BVR) and an output current regulator (OCR). DC-DC converters may be designed to process an input DC voltage and generate an output DC voltage with controlled magnitude and polarity. One way to implement such a design is through the use of pulse-width modulation (PWM). Furthermore, this topology may be designed to have an output voltage that is higher or lower than the input voltage. Some such DC-DC converters may be used in combination with a transformer and filtering components to form an isolated DC-DC converter. An isolated DC-DC converter isolates the input from the output by electrically separating the circuit into two sections, preventing direct current flow between the input and output circuits. This configuration is typically achieved through the use of a transformer. Transformers use electromagnetic induction through separate coils of wire (windings) wrapped around a common core to transfer electrical properties (voltage, current, etc.) from a primary to a secondary winding. These configurations offer numerous advantages, including the ability to handle high input voltages and high output currents while minimizing stress on power switches. Additionally, converter isolation ensures separate input and output grounds, eliminating the risk of ground loops or short circuits and improving safety.

[0056] As shown by the dashed lines in FIG. 1 , the controller 72 communicates with the batteries 12A-12D and the DC-DC converters 14A-14D. In certain examples, the controller 72 may be a battery management unit (BMU) or other similar device or system. The controller 72 may include a non-transitory memory 22 that may be computer-readable. The memory may have instructions, responsive to execution by the processor 24, that cause the controller 72 to determine battery parameters for determining the SOC and / or SOH of the batteries 12A-12D, control the flow of current through the system 10, and / or control the operation of the DC-DC converters 14A-14D in a manner described herein. The current flow is ultimately controlled based on system parameters (or system data) including the SOC, SOH, battery chemistry, temperature, current limits, etc.

[0057] The processor 24, non-transitory memory 22, and controller 72 are not particularly limited and may be physically separated, for example. In particular examples, the controller 72 may form part of a processing subsystem that includes one or more computing devices having memory, processing hardware, and communication hardware. The controller 72 may be a single device or a distributed device, and the functions of the controller 72 may be implemented by hardware and / or as computer instructions on a non-transitory computer-readable storage medium, such as the non-transitory memory 22.

[0058] In particular examples, the controller 72 includes one or more interpreters, determiners, evaluators, regulators, and / or processors 56 that functionally perform the operations of the controller 72. Descriptions herein that include an interpreter, determiner, evaluator, regulator, and / or processor emphasize the structural independence of particular aspects of the controller 72 and indicate one grouping of operations and responsibilities of the controller 72. Other groups that perform similar overall operations are understood to be within the scope of this disclosure. The interpreters, determiners, evaluators, regulators, and processors may be implemented in hardware and / or as computer instructions on a non-transitory computer-readable storage medium and may be distributed across various hardware or computer-based components.

[0059] Exemplary, non-limiting implementation elements that functionally perform the operations of controller 72 include sensors that provide predetermined values, sensors that provide any value that is a precursor to the predetermined value, data link and / or network hardware (including communication chips, oscillator crystals, communication links, cables, twisted pair wiring, coaxial wiring, shielded wiring, transmitters, receivers, and / or transceivers), hardwired logic circuits, reconfigurable logic circuits that are in a particular non-transient state configured according to module specifications, any actuators (including at least electric, hydraulic, or pneumatic actuators), solenoids, operational amplifiers, analog control elements (such as springs, filters, integrators, summers, dividers, gain elements), circuits, and / or digital control elements.

[0060] Certain operations described herein include operations for interpreting and / or determining one or more parameters or data structures. As used herein, interpreting or determining includes receiving a value from a data link or network communication, receiving an electronic signal (e.g., a voltage, frequency, current, or PWM signal) indicating a value, receiving a computer-generated parameter indicating a value, reading a value from a memory location on a non-transitory computer-readable storage medium, receiving a value as a run-time parameter in any manner known in the art, receiving a value from which the interpreted parameter can be calculated, and / or receiving a value by any manner known in the art, including by referencing a default value that is interpreted as the parameter value.

[0061] 1, in one exemplary control method for system 10, controller 72 performs various operations described in more detail below. In an embodiment, controller 72 determines battery parameters for batteries 12A-12D and commands DC-DC converters 14A-14D to control the amount of current flowing into and out of batteries 12A-12D. Controller 72 can distribute current among batteries 12A-12D so that the SOCs of all batteries are close to each other.

[0062] An example of how the SOCs of batteries 12A-12D change during operation of the above-described control method is shown in Figures 2A-2B. Figure 2A illustrates a charging event. In this example, battery 12A is ranked by controller 72 as having the highest SOC of 58, battery 12B is ranked as having a lower SOC of 60 than battery 12A, battery 12C is ranked as having a lower SOC of 62 than battery 12B, and battery 12D is ranked as having the lowest SOC of 64. When the electrical system is commanded to receive power, DC-DC converters 14A-14D are operated to charge batteries 12A-12D. Controller 72 distributes the charging current so that battery 12D receives the greatest charging current, followed by batteries 12C, 12B, and 12A. Thus, the SOC of battery 12D increases fastest, followed by batteries 12C, 12B, and 12A. After a charging event, this distribution of charging current causes the SOC of all batteries to converge to a specific value.

[0063] Similarly, FIG. 2B illustrates a discharge event. In this example, battery 12A is ranked by controller 72 as having the highest SOC of 58, battery 12B is ranked as having a lower SOC of 60 than battery 12A, battery 12C is ranked as having a lower SOC of 62 than battery 12B, and battery 12D is ranked as having the lowest SOC of 64. When the electrical system is commanded to supply power, DC-DC converters 14A-14D are operated to discharge batteries 12A-12D. Controller 72 distributes the discharge current so that battery 12A provides the greatest discharge current, followed by batteries 12B, 12C, and 12D. Thus, the SOC of battery 12A decreases most rapidly, followed by batteries 12B, 12C, and 12D. After the discharge event, the SOCs of all batteries converge to specific values.

[0064] While the example shown in Figures 2A and 2B is for SOC, similar balancing considerations exist for other parameters, such as current and SOH. In particular, Figure 2B may be most applicable to that application, since SOH is only decreasing. A lower SOH would instruct the system to use less current in both directions. However, this example is merely one of many disclosed herein and should not be construed as limiting the scope of the present disclosure.

[0065] FIG. 3 shows an example control logic 30 for implementing the principles of the present disclosure. In the illustrated example, the control logic 30 is for a system that performs charge balancing based on current and SOC. This system can be similar to that described in connection with FIGS. 1 and 2. The battery system controller used in this system can be shown in FIG. 3. It has a dynamic current limit that uses input parameters including the DC-DC converter output voltage, battery voltage, energy storage SOC, and input current limit. The output of the dynamic current limit is the output charge and discharge limit of the DC-DC converter. Note that while the DC-DC converter is imposing a limit, the current limit is set within the output limit of the dynamic current limit to prevent windup of other control loops. Charge balancing using this system applies the current limit while driving these parameters toward the system-wide average. This is exemplified by the current limiter, current balancer, and SOC balancer. The control logic 30 can determine the voltage requirements for controlling the system using the nominal voltage (defined as the design voltage value of the electrical equipment) and the output voltage (e.g., the output voltage from a transformer).

[0066] The above-described control logic 30 is only one of many examples that one skilled in the art would recognize based on the full scope of this disclosure. Another exemplary control logic 30 could use SOH as an additional input. In this example, limits or maximum values ​​related to battery chemistry, battery capacity, battery size, and temperature may be imposed. Each battery circuit in the system can be charged or discharged at a different current level while converging to a common average SOC for the system. Generally, during normal operation, the system can bias the charge or discharge current within + / - 10% to keep the SOC of all batteries within + / - 5%. These are just a few examples of the many examples disclosed herein.

[0067] The principles illustrated in FIG. 3 are translated into a flowchart in FIG. 4, which illustrates a method 40 for operating a system to perform current balancing under non-nominal conditions in accordance with the principles of the present disclosure. Some examples of method 40 are executed by a controller 72 that may be implemented in system 10. Method 40 begins by determining whether there are different batteries in the system, as shown in step 42. If there are not different chemistries in the system, method 40 proceeds to determine whether any batteries are faulty (step 44). If any batteries are faulty, the faulty battery is isolated (step 46). For example, DC-DC converters 14A-14D can inhibit current flow to or from the faulty battery, effectively isolating the faulty battery. If no faulty battery is identified, or after all faulty batteries have been isolated, method 40 proceeds to determine the average SOC of healthy batteries (step 48). For example, the average SOC of batteries 12A-12D is determined.

[0068] Faults can occur in many ways. Therefore, it would be too narrow to interpret the scope of this disclosure to mean that a fault is based on at least one parameter of system data. In fact, a battery fault can be diagnosed, for example, by a battery management system. For the systems and methods disclosed herein, it is sufficient to know that a battery is determined to be faulty (by whatever means) and the control logic excludes that battery. For batteries with very different states of charge (or other parameters), the control logic can continue to operate it, and the control logic will gradually bring it closer to the average.

[0069] After determining the average SOC of all healthy batteries (step 48), it is determined whether the SOC of each battery is within the average (step 50). For example, it is determined whether batteries 12A-12D have a sufficiently small SOC difference between each battery pack and the average. If the SOCs of batteries 12A-12D differ by only a sufficiently small amount, no balancing is required and method 40 ends (step 52). Alternatively, if it is determined that the SOC of any of batteries 12A-12D differs by more than a sufficiently small amount, method 40 proceeds to step 54.

[0070] Step 54 involves applying current limits to healthy batteries. For example, controller 72 identifies batteries 12A-12D with the highest SOC and batteries 12A-12D with the lowest SOC. To minimize system losses, controller 72 may charge / discharge only the battery with the highest SOC until its SOC reaches the minimum SOC. Controller 72 monitors the SOC of batteries 12A-12D as they change (step 56), and control method 40 repeats steps 48-56 until all SOCs are within the system range (step 50), at which point method 40 ends (step 52).

[0071] In step 42, it is determined whether there are different chemistries (batteries) in the system. If it is determined that there are different batteries, balancing prioritizes SOC over SOH (step 48). Next, the SOC of all healthy batteries is monitored (step 56). From there, method 40 continues as described above.

[0072] Referring now to FIG. 5, another example of an energy storage system according to the present disclosure is shown. System 110 is similar in many respects to system 10 of FIG. 1. However, system 110 generally includes four battery circuits 120, 122, 124, and 126, each having three batteries. Battery circuit 120 includes batteries 120A-120C, battery circuit 122 includes batteries 122A-122C, battery circuit 124 includes batteries 124A-124C, and battery circuit 126 includes batteries 126A-126C. Each battery circuit 120, 122, 124, and 126 is coupled to a DC-DC converter 140, 142, 144, and 146, which are in turn operably coupled to a load 16. Battery circuit 120 is coupled to DC-DC converter 140, battery circuit 122 is coupled to DC-DC converter 142, battery circuit 124 is coupled to DC-DC converter 144, and battery circuit 126 is coupled to DC-DC converter 146. While four DC-DC converters are shown coupled to four battery circuits having three batteries each, it should again be understood that more or fewer DC-DC converters, battery circuits, and / or batteries may be used in different applications. DC-DC converters 140-146 may be any of a variety of suitable DC-DC converters known to those skilled in the art, such as buck converters or buck-boost converters.

[0073] Returning to FIG. 4, steps 48-58 illustrate several aspects that are considered when balancing current within the system. For example, if there are four battery circuits 120, 122, 124, and 126, each requiring 100 amps, balancing among the circuits 120, 122, 124, and 126 in step 48 would prompt the system to supply 25 amps from each of the four battery circuits 120, 122, 124, and 126. Step 50 prompts the system to balance the SOC, so that more current can be distributed to the battery with the higher SOC at that time. If a battery has a much lower SOH than the other batteries, less current can be distributed to that battery (step 52). If a battery is degraded but not completely failed, current can be reduced (steps 48-56). If a battery fails, it can be isolated from the battery system (step 46). If a battery has a higher temperature than the other batteries, less current can be distributed to that battery (step 54).

[0074] Based on the SOC, temperature, and age of each battery circuit, there is a current limit in step 56. Battery chemistry can be considered under or in addition to the current limit in step 58. Due to battery chemistries (e.g., some are suitable for high power, some for high energy, etc.), all of these factors can be considered together before step 60. While summation symbols are shown, this is merely an example, and more complex weightings and equations can be used. For example, current balancing (step 48) and SOC balancing (step 50) may have higher weighting factors than the other. However, these two factors present a trade-off. For example, if the system attempts to balance the SOC, the current will become unbalanced. All of these actions can occur while the current limit is respected by the system. However, they need not all be imposed simultaneously. For example, the weighting and balancing can be range-dependent; within a certain range, the system prioritizes current balancing; in another range, the system prioritizes SOC balancing; and in yet another range, the system has a combined balancing between current and SOC. As shown in Example 5, there may be an arbitration object that achieves the appropriate requirements for a given application.

[0075] Returning to FIG. 5 , controller 72 can be in communication with battery circuits 120, 122, 124, 126, battery packs 120A-D, 122A-D, 124A-D, 126A-D, and DC-DC converters 140, 142, 144, 146, as indicated by dashed lines. In particular examples, controller 72 may be a battery management unit (BMU) or other similar device or system and may include non-transitory memory 22 having instructions that, upon execution by processor 24, cause controller 72 to determine the voltages of battery circuits 120, 122, 124, 126 and control the operation of DC-DC converters 140, 142, 144, 146 in a manner described herein. Various alternatives, aspects, and functions of processor 24, non-transitory memory 22, and controller 72 in system 110 are the same as or similar to those described above with reference to FIG. 1 and will not be repeated here.

[0076] In one exemplary control method for the system 10, the controller 72 performs various operations, which are described in more detail below. Generally, the controller 72 determines the voltages of the battery circuits 120, 122, 124, and 126 and ranks them from highest to lowest or lowest to highest. The controller 72 then commands the DC-DC converters 140, 142, 144, and 146 to control the amount of current flowing into the battery circuits 120, 122, 124, and 126. Because the batteries 120A-D, 122A-D, 124A-D, and 126A-D are connected in series, the current is the same for all battery packs. In known architectures, multiple battery packs connect to the same DC link during normal operation. Each battery pack has a simple DC-DC converter. This simple DC-DC converter is used to balance the voltages of all battery packs before they are connected to the same DC link. After the battery packs are connected to the DC link, the DC-DC converter is bypassed and never used during normal operation. However, in the present disclosure, because the common DC link is at a much higher voltage than any of the battery packs, each battery is connected to an advanced DC-DC converter. This advanced DC-DC converter is used to boost the battery voltage to the DC link level. The DC-DC remains operational at all times. Unlike known architectures, the principles of the present disclosure may not directly connect any of the battery packs to the common DC link.

[0077] FIG. 6 shows a schematic diagram of energy storage system 210. This system is similar to other systems (System 10 and System 110) previously disclosed elsewhere in this document. In this embodiment, system 210 includes multiple battery circuits (A, B, C, D) connected to a DC bus. Each of these battery circuits A-D has a dedicated DC-DC converter (214A-214D, respectively) connected in series with one or more battery packs (212A-212D, respectively). Each DC-DC converter 214A-214D is coupled to the system DC bus, which is in turn connected to a load or power source 16. A controller 72 has an associated memory 22 and processor 24 and is capable of communicating with the batteries 212A-212D and the DC-DC converters 214A-214D. The memory may contain instructions, responsive to execution by the processor 24, that cause the controller 72 to determine battery parameters for determining the SOC and / or SOH of the batteries 212A-212D, control the flow of current through the system 10, and / or control the operation of the DC-DC converters 214A-214D in a manner described herein. A distinguishing feature of the system 210 of FIG. 6 compared to those described elsewhere herein includes additional circuitry without batteries. That is, the illustrated system 210 includes an ultracapacitor circuit E connected in parallel with multiple battery circuits (A-D) and integrated into the system 210 in a manner similar to multiple battery circuits. For illustrative purposes, a miscellaneous circuit n is shown with a box "n" to indicate that other circuits (e.g., batteries, ultracapacitors, etc.) can be added to the system 210. The system 210 can transport charge to and from the ultracapacitor circuit E as needed for sudden discharge and / or sudden charge events. In both events, the system 210 can isolate any battery circuit (A-D) in the system 210 and transfer charge to or from the ultracapacitor 215. In the event of a sudden discharge, the system 210 can transfer charge to the ultracapacitor(s) 215 for storage.In the event of a sudden charging event, the system 210 can transport charge from the ultracapacitor(s) 215 to a high power storage circuit. A DC-DC converter can be provided along with the ultracapacitors. As more energy is drawn from the ultracapacitors, the voltage drops more. By having a DC-DC converter, the system can boost the voltage to equal the voltage of the common bus.

[0078] Each battery pack 212A-212D may include multiple interconnected battery packs with different connection combinations and numbers of batteries, as shown in Figures 7A-7C. For example, in Figure 7A, battery pack 212A includes multiple battery packs 120A-120C connected in series. In Figure 7B, battery pack 212B includes battery packs 120A-120B connected in parallel. In Figure 7C, battery pack 212C includes battery packs 120A-120C with a combination of parallel and series connections. However, it should be understood that the number of batteries and the specific parallel and series connection combinations may vary to comply with the output requirements of the battery pack (e.g., battery capacity, voltage, internal resistance, power output, etc.) without departing from the scope of the present disclosure.

[0079] The disclosed control logic facilitates charge balancing across multiple parallel-connected battery branches, enabling the system to maintain performance even when individual branches exhibit degraded behavior or varying characteristics. In this context, balancing is defined in terms of state of charge (SOC), and the system actively works to keep the SOC of each branch within a defined range of the system-wide average. This prevents a single branch with a low SOC from becoming a bottleneck or a source of inefficiency, thereby supporting overall system reliability and responsiveness.

[0080] System Tuning and Converter Impact

[0081] The specific behavior of the balancing logic can be tailored based on the capabilities of the DC-DC converters used in the system. Higher-end converters, e.g., those with finer control granularity, faster switching capabilities, or wider operating envelopes, allow greater flexibility in how the system manages current flow and balancing behavior. Such converters allow the control logic to respond more accurately to deviations in SOC or other battery parameters. Conversely, simpler or lower-performance converters may require tighter constraints on tolerable imbalance, limiting the system's ability to postpone balancing under transient or minor deviations.

[0082] Patentability Framework – The Benefits of Multi-Branch

[0083] The disclosed architecture offers distinct advantages in terms of redundancy and operational resilience. While incorporating multiple converters (e.g., one per branch) may increase system costs compared to traditional designs that use a single converter or only a few battery branches without balancing, it offers substantial improvements in survivability. For example, in a configuration with five parallel battery branches, the system can tolerate the complete failure or isolation of one branch (20% of the system) and continue to operate effectively. This level of tolerance is particularly valuable in mission-critical or maintenance-intensive environments and represents a meaningful differentiator over more rigid or centralized topologies.

[0084] Granular balance adjustment embodiment

[0085] In some embodiments, the system may implement balancing at a more granular level, for example, within a battery string or even between individual cells. This is particularly beneficial in applications where cells or modules with different characteristics (e.g., age, chemistry, manufacturer) are used within the same system. Control logic can monitor individual cell SOC and apply tailored current adjustments to drive convergence to uniformity, even when cells are not identical. Such fine-grained balancing improves overall system capacity, protects weak cells from overstress, and extends battery life.

[0086] Collectively, these capabilities highlight the flexibility, robustness, and adaptability of the disclosed architecture. By intelligently managing SOC balancing across multiple branches and at various levels of system granularity, and leveraging higher-end converter capabilities when available, the system can outperform traditional designs under a wider range of real-world conditions.

[0087] In the context of the disclosed battery system, the term "interface" may refer to a functional unit within each battery circuit that manages and coordinates the interaction between one or more batteries and the overall system. This interface plays a key role in enabling intelligent current distribution, charge balancing, and operational independence of each battery circuit. The specific configuration of the interface may vary based on the design and performance goals of the system.

[0088] In many implementations, the interface may include a DC-DC converter. This component is typically responsible for regulating voltage levels (stepping up or down) so that batteries can properly connect to a common DC bus regardless of individual battery voltages. The DC-DC converter may also regulate current flow to and from the batteries, ensuring that charging and discharging occur within safe and efficient operating limits. The converter may be non-isolated or isolated, depending on the safety, performance, and electrical isolation requirements of the application.

[0089] In some configurations, the interface may also incorporate a master or internal controller, such as a battery management unit (BMU) or similar control logic. This controller may receive system data (e.g., state of charge, state of health, temperature, or chemistry) and make real-time decisions about how to allocate current throughout the system. It may work in coordination with other controllers to prevent overcharge or overdischarge and isolate failed or degraded batteries from operation. These control elements, when included, improve the flexibility and reliability of the energy storage system by enabling autonomy and adaptive management for each circuit.

[0090] These examples illustrate some ways an interface may be implemented within a battery circuit, but the term is not limited to any one configuration. Depending on the particular architecture and design goals, the interface may include additional components or omit certain elements entirely. The system is designed to be adaptable, and the interface may evolve based on application needs, battery type, or performance requirements. These are some of the many possible implementations, and the term "interface" is intended to be flexibly interpreted in a manner consistent with the broader principles described throughout this disclosure.

[0091] In the context of the disclosed battery system, the term "intelligently" may refer to control strategies or behaviors that are informed by real-time system data and designed to achieve optimized performance under various conditions, including, but not limited to, making decisions regarding current distribution, charge balancing, battery isolation, and overall system operation in a manner that considers key parameters such as state of charge (SOC), state of health (SOH), temperature, current limits, and battery chemistry.

[0092] For example, the system may intelligently adjust the amount of current delivered to each battery circuit to ensure all batteries remain within a desired SOC range or converge toward a system-wide SOC average. In other scenarios, the system may reduce current to batteries showing signs of degradation or temporarily isolate a failed battery to maintain stability and avoid compromising system reliability. These decisions may be based on predefined rules, dynamic algorithms, or responsive control logic designed to minimize energy loss, extend battery life, and adapt to changing load demands.

[0093] In some implementations, intelligent behavior may be facilitated by a dedicated controller or battery management unit (BMU) that processes input signals from multiple battery circuits and uses control algorithms to make system-wide adjustments. These adjustments may include dynamic current limiting, fault detection and response, or charge / discharge bias based on battery condition or chemistry. However, intelligent control does not necessarily require complex algorithms or centralized control, but may also include simpler rule-based behavior that contributes to improved system functionality.

[0094] These are just a few ways the term "intelligently" can be applied in the context of systems. The term is used broadly to describe behavior that is responsive, adaptive, and guided by relevant operational data. It is not limited to any particular form of artificial intelligence, algorithm, or level of complexity, and can encompass a wide range of practical implementations depending on the design and performance goals of the energy storage system.

[0095] Fine-grained SOC-based current balancing using DC-DC converters

[0096] In certain embodiments, a battery system may include multiple battery cells or modules. State-of-charge (SOC) imbalances among these cells or modules can result in one unit reaching its charge or discharge limit before the others, thereby limiting overall system performance. Fine-grained current balancing can address such imbalances by actively redistributing energy among the cells or battery modules to ensure their respective SOCs converge within desired thresholds. A DC-DC converter can serve as an enabling component for such active balancing. Unlike passive balancing approaches in which excess charge is dissipated as heat, a DC-DC converter can transfer energy from units with higher SOCs to units with lower SOCs, thereby facilitating charge equalization.

[0097] The level of sophistication of a DC-DC converter implementation can impact the accuracy and responsiveness with which SOC-based balancing can be achieved under dynamic operating conditions. High-performance DC-DC converters may incorporate features that enable real-time adjustment of balancing currents based on SOC parameters. In certain embodiments, such converters may function as intelligent energy routing devices, facilitating bidirectional energy transfer, voltage matching, and current coordination across multiple battery modules.

[0098] In some examples, high-performance DC-DC converters may support a wide input / output voltage range. Such capability allows the converter to accommodate full SOC swings and enables energy transfer even between modules with significantly different voltages. For example, a converter configured to perform both step-up and step-down operations can regulate voltage under both charging and discharging conditions.

[0099] Certain DC-DC converters may also exhibit fast transient response, allowing for rapid adjustment of output current in response to system data indicating SOC deviations or load changes. For example, if a battery module begins to deplete faster than others, the converter can quickly reallocate current to maintain charge balance and prevent over-discharge. This capability can be particularly advantageous in mobile systems where acceleration, regenerative braking, and transient loads are common.

[0100] In some embodiments, a DC-DC converter may support bidirectional power flow. Bidirectionality allows the converter to either extract energy from or supply energy to a given battery module. This allows it to push charge to a lower SOC module and draw charge from a higher SOC module as needed. Converters without bidirectional capability are limited to unidirectional regulation, which can limit their ability to rebalance the system during both charging and discharging events.

[0101] Additional converter features may include programmable current limiting and digitally adjustable current control. These features allow the system to finely adjust the balancing current, enabling controlled convergence of SOC values ​​across the battery system. For example, a battery management system (BMS) may command the converter to provide a specific balancing current to lower SOC modules until equilibrium is reached. Furthermore, the control logic may taper the current as convergence approaches, reducing stress on individual cells.

[0102] Some DC-DC converter topologies may include galvanic isolation between the input and output stages. Isolation may be required when battery modules are arranged in series strings or referenced to different ground potentials. Isolated converters can assist in energy transfer between otherwise electrically incompatible circuits, improving the flexibility of system architectures.

[0103] High-performance DC-DC converters may further include embedded control logic, such as a microcontroller or digital signal processor (DSP). These embedded controllers may execute local control algorithms that respond to measured parameters, such as module voltage, current, or SOC. In certain configurations, the converter may also include a communications interface that facilitates coordination with a central BMS or supervisory controller via a protocol such as CAN.

[0104] In contrast, basic DC-DC converter designs lacking one or more of the aforementioned features may offer limited support for SOC-based balancing. For example, a non-isolated unidirectional buck converter may be able to reduce the voltage from a high-SOC module to a load, but may not be able to boost the voltage or perform bidirectional regulation. Such converters may operate within a narrow voltage window, offer fixed or limited control behavior, and lack responsiveness to real-time SOC data. In general, systems relying solely on such converters cannot dynamically redistribute energy between modules, and any balancing that occurs may be limited to coarse, delayed, or charge-only scenarios.

[0105] Therefore, systems utilizing high-performance DC-DC converters are capable of fine-grained SOC balancing, allowing modules of different capacities, chemistries, or health states to operate in parallel while maintaining system-level efficiency and stability. This enables the cooperative use of heterogeneous batteries and supports applications where charge regulation, balancing responsiveness, and converter flexibility are critical.

[0106] Energy Storage Systems (EMS) Overview and Integration

[0107] According to various implementations, the energy storage system 210 (also known as an “energy management system” (EMS)) disclosed herein comprises a network of battery circuits, DC-DC power converters, and controller interfaces arranged to manage energy flow in both mobile and stationary power applications. The EMS 210 can be implemented using a centralized control architecture, a distributed control architecture, or a hybrid thereof. In a centralized implementation, a master controller oversees all battery circuits and regulates current flow based on system-level data. In a distributed implementation, each battery circuit may include or be paired with a local controller, which monitors operating parameters and communicates with other controllers in the system. A distributed implementation offers improved fault tolerance and system scalability, allowing continued operation despite failures in a single circuit and enabling the integration of additional battery circuits with minimal reconfiguration.

[0108] Each battery circuit may include one or more electrochemical storage elements (e.g., battery cells or modules) and may be operably coupled to a common DC bus via a bidirectional DC-DC converter. This configuration allows EMS 210 to independently regulate the charging and discharging activity of each battery circuit, thereby facilitating overall system control and optimization. In various embodiments, the controller interface may include a wired or wireless communications link and is configured to exchange control signals and measurement data with other system components, including a vehicle control unit and / or a grid tie controller.

[0109] Application environments and use cases of energy storage systems

[0110] The energy management system (EMS) disclosed herein may be implemented as part of or in combination with an integrated power system. As used herein, "integrated power system" may refer to a system that includes one or more of: generator sets, alternators, switchgear, load control devices, energy storage systems, microgrid controls, power electronics, or combinations thereof. Such integrated power systems may be configured to operate in various modes, including primary power, standby power, cogeneration, or as a grid-tied or islanded microgrid.

[0111] 8 is a flow chart of an example integrated power system 310 including an energy storage system (EMS) 210, a generator 312, and an interface 314 that supplies energy to a load 316. As shown, the EMS 210 may be incorporated into the integrated power system 310 deployed across a variety of application environments or loads 316, including, but not limited to, residential, commercial, industrial, healthcare, data centers, mining operations, oil and gas platforms, communications infrastructure, offshore systems, and rail support systems. In each of these settings, the EMS 210 may be used to monitor and control energy storage assets, manage current balancing, coordinate transitions between power sources, and support uninterrupted or optimized energy delivery.

[0112] In commercial or industrial deployments, the integrated power system 310 may include a high-horsepower generator set 312 and modular battery circuits managed by an EMS. In such configurations, the EMS 210 may provide load support during peak demand, facilitate dynamic current redistribution among battery circuits, or assist with generator ramping and load transitioning. The EMS 210 may also coordinate with switchgear or supervisory controllers that manage facility-wide protection, load shedding, or energy prioritization.

[0113] In backup or standby applications, the EMS 210 may manage the charging and discharging of batteries integrated into the overall power system that would otherwise be supported by generator assets. The EMS 210 may respond to a utility outage by immediately supplying critical loads using stored battery energy and maintain this support until the generator 312 achieves synchronization. Once the generator is ready, the EMS 210 may transfer energy supply without introducing voltage transients or service interruptions. Similarly, during a return to grid power or generator shutdown, the EMS 210 may resume load support and manage the recharging of the battery circuits.

[0114] In a microgrid environment, the integrated power system 310 may incorporate multiple distributed power generation sources 312, such as photovoltaic panels, wind turbines, and engine-driven generators. The EMS 210 may be configured to coordinate energy dispatch among these sources and regulate current flow among multiple battery circuits. It may maintain DC or AC bus stability, support grid-following or grid-forming behaviors, and manage load sharing using centralized or decentralized strategies (e.g., droop control). The EMS 210 may also balance the system among heterogeneous battery modules and enable energy time shifting, peak shaving, or spinning reserve capabilities.

[0115] In mobility and transportation-related applications, such as offshore power systems and rail support platforms, the EMS 210 may be embedded within an integrated power system 310 that includes onboard power generation and modular energy storage. In these cases, the EMS 210 may coordinate hybrid energy usage, manage transient load events, or maintain power supply while isolating failed modules.

[0116] The EMS 210 may be implemented using scalable controller hardware and DC-DC power converters. A centralized EMS 210 configuration may include a master controller or interface 314, which collects system data from all battery circuits and manages balancing logic across the entire installation. A distributed EMS configuration may utilize controllers per module capable of autonomous operation through coordination via wired or wireless communication links. The EMS may also interface to a site supervisory control and data acquisition (SCADA) system, remote diagnostic tools, or a cloud-based fleet management platform.

[0117] The EMS 210 disclosed herein may therefore be integrated into a wide range of stationary and mobile integrated power systems 310. Its modular architecture, support for diverse battery technologies, real-time control capabilities, and fault-tolerant design enable it to provide energy balancing, system protection, and coordinated energy dispatch in demanding environments.

[0118] EMS Integration in Electrified Vehicle Powertrains

[0119] In vehicle applications, an EMS may be integrated to manage energy exchange between a traction battery pack, one or more electric drive units, and vehicle accessories. The traction battery pack is typically coupled to the vehicle propulsion system via a high-voltage DC link and an inverter that drives the electric motor. The EMS may manage power delivery from the battery to the inverter during propulsion and coordinate energy recovery during regenerative braking. For example, during a deceleration event, the EMS may command a DC-DC converter or inverter to limit charging current within safe thresholds, even while the motor is operating in generating mode.

[0120] The EMS may also interface with one or more auxiliary DC-DC converters that regulate the voltage between the high-voltage traction battery and the low-voltage (e.g., 12V) subsystem. These converters power the auxiliary components and may also be configured to maintain charge in lead-acid or lithium-based auxiliary batteries, thereby eliminating the need for an alternator in the electric vehicle.

[0121] In some embodiments, the EMS is configured to regulate multiple battery circuits within a vehicle. For example, if a vehicle includes both high-power and high-energy storage modules, the EMS may allocate energy supply duties based on module capabilities. The high-power module may be prioritized during acceleration events, while the high-energy module may be used for sustained cruising. The EMS may also adapt to differences in state of health (SOH), chemistry, or capacity between modules and adjust charge and discharge rates accordingly to extend module life and optimize performance.

[0122] The EMS may also include safety and fault mitigation functions. In the event of an overvoltage or overtemperature condition, the EMS may isolate the affected module by opening a contactor or disabling the associated DC-DC converter. Vehicle operation may continue in a derated or limited power mode using the remaining functional modules.

[0123] The EMS may communicate with the wider vehicle network (e.g., via CAN bus or similar protocol) and is operable to receive commands (e.g., torque requests) and report diagnostics (e.g., SOC, SOH, fault conditions). The EMS may also interface with AC or DC charging infrastructure, manage charge rates based on internal and external conditions, and coordinate transitions between different power modes. Overall, the EMS enables dynamic, safe, and efficient energy management throughout the electrified vehicle powertrain.

[0124] EMS Integration in Stationary Energy Storage Systems

[0125] In stationary applications, the EMS may be deployed in systems including, but not limited to, generator-assisted energy storage units, microgrids, uninterruptible power supply (UPS) systems, and hybrid energy systems configured for primary or standby power. In such systems, each battery circuit may be connected to a common DC bus via a respective bidirectional DC-DC converter. This allows for independent regulation of each battery circuit and supports scalable system designs.

[0126] The EMS may regulate the overall bus voltage and manage energy distribution between power sources and loads. In some configurations, the DC bus may also interface with renewable energy generators (e.g., photovoltaic or wind-based systems) and power inverters, where the power inverters power AC loads or synchronize with the utility grid. The EMS may monitor real-time operating conditions such as voltage, current, SOC, SOH, and temperature, and may adjust charge and discharge rates to optimize performance and protect individual battery circuits.

[0127] In grid-connected systems, the EMS may interface with bidirectional inverters to export or absorb energy in coordination with grid events or utility commands. The EMS may also support ancillary services such as frequency regulation, demand response, or peak shaving.

[0128] In systems where generators are present, the EMS may balance generator output with battery contribution. For example, during periods of low load, the EMS may prioritize charging. During high-demand events, it may limit generator ramping by discharging stored energy. In a standby configuration, the EMS may provide instantaneous power to critical loads during utility outages, filling the gap until generators come online. The EMS may also manage generator startup, grid reconnection, or seamless transitions during shutdown conditions.

[0129] In an islanded microgrid, the EMS may work in collaboration with the microgrid supervisory controller or operate autonomously to maintain bus stability, frequency, and voltage targets. Using local measurements and system models, the EMS may allocate current commands to individual battery circuits based on their SOC and other operational constraints.

[0130] The EMS architecture supports modularity, allowing individual battery circuits to be added, removed, or isolated without interrupting the operation of the overall system. The control framework may include fault detection and isolation logic. Upon identifying a heretical or degraded module, the EMS may disconnect the associated converter and rebalance the system using the remaining healthy units.

[0131] Functional controls and features for modularity and reliability

[0132] The EMS is configured to regulate current flow throughout the system to maintain stability, optimize efficiency, and extend battery life. Through coordinated control of DC-DC converters and embedded algorithms, the EMS may dynamically adjust current commands, duty cycles, or voltage targets to respond to real-time conditions.

[0133] In a multi-source configuration, the EMS may implement load sharing schemes, such as droop control or master-slave control logic, to allocate current among the battery circuits or generating units. These control schemes may also respond to SOH and temperature data, allowing for adaptive behavior as modules age or operating conditions change.

[0134] A further function of the EMS is to balance the SOC among distributed battery circuits. The EMS may reduce the load on low SOC modules and increase the use of high SOC modules until SOC values ​​converge. In systems with heterogeneous battery technologies or aging modules, the EMS may apply differentiated control parameters to maximize total available energy while preventing over-discharge or over-charge conditions.

[0135] The EMS may incorporate local and centralized fault detection systems. Each battery circuit may be monitored for overvoltage, undervoltage, overcurrent, thermal excursion, or internal fault indicators. Upon detecting a fault, the EMS may initiate protective action, including converter shutdown, contactor opening, or thermal derating. Fault notification may be propagated via wired or wireless communication to an operator, system log, or supervisory controller.

[0136] Importantly, the EMS supports heterogeneous integration. Battery strings with different chemistries, capacities, or manufacturers may be deployed on the same DC bus and maintain operational independence through converter-level isolation. Converter control parameters may be adjusted based on stored or learned characteristics of each string. The EMS may also recalibrate SOC or SOH tracking of older modules and reallocate loads accordingly.

[0137] The modular and scalable design of the EMS allows for deployment in configurations ranging from small vehicle battery packs to utility-scale energy storage installations. The EMS control architecture may automatically detect, configure, and manage newly added or replaced battery circuits. A hierarchical or agent-based control model may be implemented to distribute control tasks between local module controllers and a central EMS coordinator.

[0138] In summary, the EMS disclosed herein enables flexible, fault-tolerant, and data-driven energy management for both mobile and stationary applications. Through modular converter integration, dynamic current regulation, and system-wide coordination of battery behavior, the EMS supports safe and efficient energy storage operation across a wide range of use cases.

[0139] kit

[0140] Any device, system, method, or controller described elsewhere herein can be readily implemented, organized, or provided as part of a battery balancing kit. As used in this context, a “kit” refers to a packaged or modular assembly comprising one or more hardware components, such as a DC-DC converter, a controller, wiring, connectors, a housing, or a software storage medium, configured to be integrated into an existing or newly designed energy storage system. Kit components may be preassembled or provided in separate modules and configured for implementation by an end user, system integrator, or original equipment manufacturer (OEM). In various implementations, the kit may include any subcombination of the control logic, energy routing hardware, sensor interface, or communication elements disclosed herein, so long as they are adapted to be used in concert to regulate current distribution among parallel-connected battery circuits. Thus, references to control architectures, fault handling routines, balancing methods, or system-level strategies, whether disclosed individually or in combination, should be understood to optionally form part of the kit. The following paragraphs provide examples of how such kits may be applied across various vehicle and infrastructure systems.

[0141] In various implementations, the battery balancing kits disclosed herein can be used to retrofit or upgrade electric or hybrid transportation systems across on-highway, off-highway, and rail applications. In on-highway applications, such as medium- and heavy-duty vehicles configured for urban or long-distance transportation, the kits can be integrated into existing energy storage architectures to accommodate new battery modules without requiring a complete replacement of the legacy system. This allows vehicles to incorporate batteries with different chemistries, capacities, or health states, and the kit's controller uses system data to adjust current distribution to ensure safe and efficient operation. For example, if some battery modules are partially degraded and others are newly installed, the controller preferentially allocates current to healthier modules, thereby extending the system's usable life while preventing undue stress on weaker batteries.

[0142] In off-highway applications, such as construction, mining, or agricultural equipment, the kit enables hybridization or full electrification using disparate energy storage resources. These vehicles often face highly variable load demands, including repeated cycles of heavy acceleration, regenerative braking, or idle operation. The kit may be configured to manage multiple battery strings optimized for either high power or high energy delivery, and can optionally incorporate ultracapacitor-based storage elements. In such scenarios, the control architecture dynamically adjusts current commands based on instantaneous operating parameters, such as torque demand, temperature, and state of charge, to optimize performance, reduce thermal stress, and prevent simultaneous charging and discharging within the system. This results in energy-efficient operation and enables robust thermal and lifecycle management.

[0143] In rail transportation applications, including freight or passenger locomotives employing diesel-electric or all-electric traction, the kit may be installed to augment or replace existing battery systems. Locomotive platforms are often subject to operational constraints that require high peak power output during acceleration and energy absorption during regenerative braking. The disclosed kit enables modular deployment of new battery technologies alongside legacy systems and provides the ability to isolate underperforming or failed strings in real time. The controller facilitates charge balancing between independent circuits using current commands derived from centralized control logic, thereby enabling robust integration into the high-voltage direct current (DC) link architecture common in such propulsion systems.

[0144] Overall, the battery balancing kit improves the adaptability of electrified transportation systems by enabling modular battery replacement, chemistry-independent expansion, and fault-tolerant operation. It is particularly suited for retrofit applications where maintaining compatibility with existing infrastructure and managing aging battery modules are key design requirements. By providing per-string DC-DC conversion and system-wide current coordination based on state-of-charge, state-of-health, chemistry, and thermal parameters, the kit offers a flexible and scalable upgrade path for modernizing energy storage systems in a wide range of transportation environments.

[0145] Practical examples

[0146] Example 1: No requirement to balance battery SOC

[0147] In one practical implementation, Battery A can be 500V, and DC-DC Converter A can boost the 500V to 1000V. Battery B can be 600V, and DC-DC Converter B can boost the 600V to 1000V. Although Batteries A and B have different voltages (and therefore different SOC values), their DC-DC converters can boost their voltages to the same level. In this way, this architecture avoids using a higher-voltage battery to charge a lower-voltage battery.

[0148] Balancing the SOC based further on the principles of the present disclosure can improve this example. First, it may be best to keep the battery SOC within a range of 20% to 80%. If the battery SOC is above 80% or below 20%, it becomes more difficult to charge or discharge the battery, resulting in a loss of some charge and / or discharge capacity. To keep all batteries' SOCs within a range of 20% to 80%, one strategy is to keep all SOCs at the same level and increase or decrease the SOC at the same pace. If the SOC of any battery deviates from the others, the control architecture can distribute the charge or discharge current so that the SOC difference is smaller. For example, Battery A is at 60% SOC and Battery B is at 50% SOC. With a discharge current command of 100 A, the control architecture can instruct Battery A to discharge at 70 A and Battery B to discharge at 30 A. Because Battery A is discharging more current, its SOC decreases faster than Battery B. After a period of time, Batteries A and B will have similar SOCs, and the control architecture can then direct Batteries A and B to discharge the same amount of current. Under these circumstances, rather than using Battery A to charge Battery B, the control architecture will discharge them simultaneously, but at different currents, balancing their SOCs over time.

[0149] Example 2: Battery usage allocation based on SOH

[0150] In another example, further based on the principles of the present disclosure, the control architecture can use batteries with higher SOH more frequently. In some cases, balancing SOH may conflict with balancing SOC. In such cases, the control architecture can employ one or more measures to manage these trade-offs. As alluded to above, SOH is something like a percentage of remaining life. SOH can be estimated based on voltage / current measurements. Ideally, the control architecture manages all batteries so that they all age at the same rate, postponing the replacement of a battery pack when it reaches the end of its life.

[0151] With an understanding of these principles, the systems 10, 110 described above can be adapted (e.g., by design and / or manufacturing differences) to incorporate battery chemistries. For example, batteries can be selected based on specific power requirements, and the systems 10, 110 can select batteries of different chemistries based on torque demands on the systems 10, 110. In addition to this, consider multiple battery circuits (sometimes referred to herein as "strings") that include at least one circuit (e.g., a "high-power circuit") with a high-power battery and at least one circuit (e.g., a "high-energy circuit") with a high-energy battery. The high-power battery can release its stored energy quickly, while the high-energy battery releases its stored energy slowly.

[0152] Combining this dynamic with the control architecture disclosed elsewhere herein, the system 10, 110 can be configured to provide a continuous supply based on current or anticipated demand. For example, if a load benefits from current drawn from the high power circuit, the control architecture can isolate all other battery circuits so that current is drawn only from the high power circuit. Conversely, if a load benefits from current drawn from the high energy circuit, the control architecture can isolate all other battery circuits so that current is drawn only from the high energy circuit.

[0153] Depending on the amount and nature of the demand, the system can utilize several battery strings to meet it. As a simple example of this feature, the system 10, 110 can coordinate the use of a high-power battery with a maximum discharge capacity of 500 kW and a high-energy battery with a maximum discharge capacity of 250 kW to utilize the strengths of each battery. If the load is a very steady 250 kW, the system can use 250 kW from the high-energy battery to meet the power demand. If the power demand suddenly increases to 750 kW, the system can use 500 kW from the high-power battery and 250 kW from the high-energy battery to meet the power demand. During this operation, the system can still perform balancing based on, for example, SOC and any current limits.

[0154] In such a setup, each battery string has its own dedicated DC-DC converter, so it is not necessary to have the voltage of each string at the same level on the DC bus, since each battery string can operate independently of the others by being brought online or offline by its own dedicated DC-DC converter.

[0155] Example 3: On-Highway Hybrid Vehicle

[0156] In an exemplary implementation of this aspect of the present disclosure, system 210 can be incorporated into an on-highway hybrid vehicle. Such a vehicle can employ multiple operating modes, some or all of which can utilize historical data (e.g., driving patterns, terrain, geographic location, etc., or a combination thereof) and look-ahead data (e.g., roadmap and / or navigation data). Traditional hybrids maintain an SOC of approximately 50% to receive or provide power using a battery rather than a connected internal combustion engine (or “ICE”). Energy from the battery is used to supplement the ICE whenever possible (e.g., when the battery is at 50% SOC), or if the battery is depleted, the ICE charges the battery back to approximately 50%. However, a hybrid system of the present disclosure can minimize when the ICE is used to charge the battery. With look-ahead, the vehicle can recognize potential regeneration opportunities along its trajectory and prepare to avoid overcharging the battery with regeneration opportunities. Look-ahead is particularly useful in mining, where routes are predictable and often replicated during operations. Regeneration generally occurs on downhill sections so that all peak power is stored at or near the bottom of the route. If the battery is already full on the downhill section, regeneration may not occur.

[0157] Employing system 210 can be advantageous in this example. If there is a regeneration event ahead, the potential regeneration may be greater than the battery can capture (in kW), so the vehicle may send the excess regeneration to a resistor and dissipate it as heat. Alternatively, using system 210, the vehicle can instead send the high regeneration energy to a high-power battery string (or ultracapacitor string) and / or coordinate the sending of some of the high regeneration energy between the high-power battery string (or ultracapacitor string) and the high-energy battery string. In another alternative, system 210 can operate the vehicle using a high-energy battery in combination with a high-power battery and / or ultracapacitors, thereby allowing the vehicle to operate without an ICE. Under these circumstances, the high-power battery and / or ultracapacitors can "work" in coordination with the high-energy battery in a manner similar to the ICE described above.

[0158] Example 4: High-energy battery EV

[0159] Those skilled in the art will understand that similar principles can be applied to battery electric vehicles. Instead of an ICE, the vehicle can now have system 210 with a high-energy battery for long-term needs (e.g., non-peak loads) and a high-power battery for start-stop loads. For example, the system can have at least one string (e.g., string A) as a high-power battery string and at least one string (e.g., strings B-D) as a high-energy battery. The high-power battery can operate like the ICE in the hybrid system described above. The high-power batteries can be kept at approximately 50% SOC in preparation for donating or receiving large amounts of energy. The SOCs of the high-energy batteries can be kept close to each other (e.g., using current regulation), as described elsewhere herein. Keeping the SOCs nearly the same maximizes battery life, minimizes depth of discharge, and minimizes battery overcharging. In this way, system 210 can maximize the life and cycle count of the high-energy battery. From a maintenance perspective, this allows, for example, replacing all worn-out batteries at once or replacing the high-energy battery at once without having to change the high-power battery. If high-power batteries are used sparingly, this can result in significant cost savings, and also provide greater reliability, given that high-energy batteries tend to be more maintainable or available. The trade-off that system 210 can balance is between performance due to high-energy or high-power characteristics and life-span management of high-energy and high-power batteries.

[0160] Example 5: Arbitration Object

[0161] For example, if there is a demand for 1000 amps with five converters running at 200 amps each, the default may be to command 200 amps to each. If the current limit allows 210 amps, the current command to the battery circuit with a lower SOC than all the other batteries may be reduced to 180 amps, and the 20 amp reduction may be compensated for by increasing the default 200 amps to 205 amps on the other four battery circuits. The current limit is a function of state of charge, temperature, battery chemistry, and battery age as provided by the battery manufacturer. The system may respect the current limit.

[0162] guidance

[0163] The following section provides interpretive guidance for understanding and applying the principles described in this disclosure. It outlines key concepts related to embodiment flexibility, parameter variation, structural adaptability, and claim interpretation for a battery system for intelligently distributing current among multiple batteries. This section introduces representative principles to help practitioners interpret the scope and implementation of the disclosed system, but is not exhaustive and should not be construed as limiting. Rather, it serves to aid in a clear, applicable, and technically sound understanding of the embodiments and their potential equivalents under applicable patent law.

[0164] While the invention has been described as having exemplary designs, the invention can be further modified within the spirit and scope of the disclosure. Accordingly, this application is intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover any departures from the present disclosure that come within known or customary practice in the art to which this invention pertains and that fall within the scope of the appended claims.

[0165] Furthermore, the connecting lines shown in the various figures contained herein are intended to represent exemplary functional relationships and / or physical couplings between the various elements. It should be noted that many alternative or additional functional relationships or physical connections may exist in a practical system. However, benefits, advantages, solutions to problems, and any elements that may cause or make more pronounced a benefit, advantage, or solution should not be construed as critical, essential, or essential features or elements. Therefore, the scope should not be limited except by the appended claims. In the claims, when an element is referred to in the singular, this is not intended to mean "one and only," unless expressly stated otherwise, but rather "one or more." Ranges provided in this disclosure should be construed to include both their stated endpoints and any intermediate values, unless expressly indicated otherwise. Unless otherwise specified, a range or single value should be understood to include values ​​that one of ordinary skill in the art would generally consider equivalent or sufficiently close for the intended function, varying plus or minus by a reasonable percentage appropriate in the art. When used in conjunction with ranges or values, phrases such as "generally within," "approximately," "about," "substantially," "approximately," "sufficiently," or similar modifiers are intended to allow for practical engineering and manufacturing tolerances, measurement uncertainties, and performance margins without limiting the claims to absolute numerical boundaries. When a single value or limit is disclosed without an explicit range, it should be construed to encompass that value and all functionally equivalent values ​​within such reasonable variations, consistent with the doctrine of equivalents.

[0166] The use of modifiers such as "about," "generally," "substantially," "sufficiently," and similar terms is intended to capture acceptable variations that do not materially affect the intended operation or performance of the described system. These terms do not narrow the scope of the claims to exact numerical values ​​unless expressly stated otherwise.

[0167] Furthermore, when a claim uses phrases similar to "at least one of A, B, or C," the phrase is intended to be interpreted to mean that only A may be present in an embodiment, or only B may be present in an embodiment, or only C may be present in an embodiment, or any combination of elements A, B, or C may be present in a single embodiment, e.g., A and B, A and C, B and C, or A, B and C.

[0168] Systems, methods, and apparatus are provided herein. In the detailed description herein, references to "examples," "embodiments," "exemplary embodiments," and the like indicate that the described embodiments may include a particular feature, structure, or characteristic, but not all embodiments necessarily include that particular feature, structure, or characteristic. Moreover, such phrases do not necessarily refer to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic with the benefit of this disclosure in connection with other embodiments, whether or not explicitly described. After reading the description, it will be apparent to one skilled in the relevant art how to implement the present disclosure in alternative embodiments.

[0169] Furthermore, no element, component, or method step in this disclosure is intended to be made available to the public regardless of whether that element, component, or method step is expressly recited in a claim. No claim element herein is to be construed under the provisions of 35 U.S.C. § 112(f) unless the element is expressly recited using the phrase "means for." As used herein, "comprises," "comprising," or any other variation thereof, is intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus comprising recited elements may include not only those elements, but also other elements not expressly recited or inherent to such process, method, article, or apparatus.

[0170] For the purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to the embodiments illustrated in the drawings and described elsewhere in this document. The exemplary embodiments disclosed herein are not intended to be exhaustive or to limit the disclosure to the precise forms disclosed in the detailed description. Rather, these illustrative examples were chosen and described to enable others skilled in the art to utilize their teachings.

[0171] "Couple," "coupled," and variations thereof are used to include both arrangements in which two or more parts are in direct physical contact, and configurations in which two or more parts are not in direct contact with each other (e.g., the parts are "coupled" through at least a third part), but still cooperate or interact with each other. Furthermore, "couple," "coupled," and variations thereof refer to any connection of mechanical parts known in the art, including, but not limited to, bolts, screws, threads, magnets, electromagnets, adhesives, friction grips, welds, snaps, clips, etc.

[0172] Throughout this disclosure and in the claims, numerical terms such as first and second are used to refer to various components or features. Such use is not intended to indicate an ordering of the components or features. Rather, the numerical terms are used to aid the reader in identifying the component or feature being referenced and should not be narrowly construed as conferring a particular ordering of the components or features.

[0173] Those skilled in the art will appreciate that the provided embodiments may be implemented in hardware, software, firmware, and / or combinations thereof. Programming code according to the embodiments may be implemented in any executable programming language, such as C, C++, HTML, XML, JAVA, or any other executable high-level programming language, or a combination of high-level and low-level programming languages.

[0174] As used herein, "battery" or variations thereof can refer to one of many different types, each of which is recognizable by one of ordinary skill in the art. For example, a "battery" can include a collection of battery cells, battery modules, module-pack configurations, cell-pack configurations, etc. Such variations are contemplated and are fully within the scope of the present disclosure.

[0175] The structures, materials, methods, and compositions described herein are intended to illustrate, rather than limit, the scope of the present invention. All modifications, substitutions, equivalents, and functional alternatives that achieve the stated objectives using different structures, whether now known or later developed, are intended to be within the scope of the appended claims and are protected under applicable patent law, including the doctrine of equivalents.

Claims

1. A battery system comprising a plurality of battery circuits connected in parallel, each battery circuit comprising: a plurality of batteries connected in series and / or parallel, each battery configured to store energy for use in the battery system; a DC-DC converter operably connected to the plurality of batteries, the DC-DC converter configured to control current flow to the plurality of batteries based on system data during operation of the battery system; A battery system comprising:

2. The battery system of claim 1 , wherein the system data includes at least one of a current, a state of charge, and a state of health.

3. 3. The battery system of claim 1 or 2, wherein the system data further includes at least one of battery temperature, battery chemistry, and current limits.

4. 3. The battery system of claim 1, further comprising a controller operably connected to each DC-DC converter, the controller configured to receive and process the system data from the plurality of battery circuits.

5. 5. The battery system of claim 4, wherein the controller is configured to distribute current among the plurality of battery circuits to balance states of charge.

6. 5. The battery system of claim 4, wherein the controller is configured to identify a battery circuit as faulty and isolate the faulty battery circuit from operation.

7. 5. The battery system of claim 4, wherein the controller is configured to prevent charging of any battery when the battery system is supplying power and to prevent discharging of any battery when the battery system is receiving power.

8. The battery system according to any one of claims 1 to 4, wherein the number of the battery circuits is three or more.

9. A method of operating a battery system according to any one of claims 1 to 8, comprising the steps of: receiving system data from the plurality of battery circuits; controlling current flow in at least one of the plurality of battery circuits based on the system data; balancing the plurality of battery circuits based on the system data; A method comprising:

10. 10. The method of claim 9, further comprising identifying a fault in a battery circuit based on the system data and isolating the battery circuit from operation.

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