Energy storage system and method using second-life electric vehicle batteries

Abstract

A system and method for energy storage using second-life EV batteries is provided. The disclosed system includes a plurality of EV battery packs and a processor configured to couple the plurality of EV battery packs in a series / parallel arrangement. The series / parallel arrangement includes a plurality of series strings of EV battery packs, each of the plurality of series strings of EV battery packs including at least two of the plurality of EV battery packs coupled in series, and the plurality of series strings of EV battery packs connected in parallel. The coupling of the plurality of EV battery packs includes one or more of a series connection of EV battery packs having a lower voltage, a series connection of EV battery packs having a higher voltage, a series connection of EV battery packs having a majority voltage, and a parallel connection of EV battery packs within a programmed voltage connection window.

Description

[Technical field]

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS] This application is a PCT application based on U.S. Patent Application No. 17 / 675,456, filed February 18, 2022, which is a continuation-in-part of U.S. Patent Application No. 17 / 382,933, filed July 22, 2021, which is a continuation-in-part of U.S. Patent Application No. 17 / 118,497, filed December 10, 2020. Each of these applications is incorporated herein by reference in its entirety.

[0002] The present disclosure relates generally to energy storage systems and methods using second-life electric vehicle batteries, and more particularly to an integrated battery energy storage system that includes multiple electric vehicle battery packs connected in a series / parallel arrangement to maximize yield from the multiple electric vehicle battery packs at different states of health (SOH). [Background technology]

[0003] Reducing the cost of energy storage systems (ESS) is an important goal for energy ratepayers and policymakers. The primary metric for measuring the cost of energy storage systems is the levelized cost of storage (LCOS). Levelized cost of storage is defined as the total lifetime cost of the storage system, including construction capital costs and operational costs, divided by the cumulative amount of electricity stored by the system for transmission.

[0004] Reusing electrochemical batteries from electric vehicles (EVs) for secondary use or second-life stationary storage applications can significantly reduce the levelized storage cost of the energy storage system compared to using new batteries. Utilizing electric vehicle batteries for stationary storage applications is the highest and best use of the batteries when they are no longer suitable for use in an electric vehicle. The result is a second-life battery pack that can return many times its initial investment before being disassembled for component recycling. Larger energy storage systems require many batteries arranged in series and parallel electrical configurations to deliver energy at high voltage and current levels. For an energy storage system to function effectively, batteries must be efficiently integrated and managed over time and across charge and discharge cycles, whether the energy storage system is electrically connected in front of or behind the customer's meter. Summary of the Invention [Means for solving the problem]

[0005] Within the overall energy storage system (ESS), a system that utilizes multiple electric vehicle (EV) batteries for second-life stationary energy storage applications is desirable.

[0006] According to one aspect, an integrated battery energy storage system is disclosed comprising: a plurality of electric vehicle battery packs; and a computer system including a processor configured to couple the plurality of electric vehicle battery packs in a series / parallel arrangement, the series / parallel arrangement including a plurality of series strings of electric vehicle battery packs, each of the plurality of series strings of electric vehicle battery packs including at least two of the plurality of electric vehicle battery packs coupled in series, the plurality of series strings of electric vehicle battery packs being connected in parallel, the coupling of the plurality of electric vehicle battery packs including one or more of a series connection of electric vehicle battery packs having a lower voltage, a series connection of electric vehicle battery packs having a higher voltage, a series connection of electric vehicle battery packs having a majority voltage, and a parallel connection of electric vehicle battery packs within a programmed voltage connection window.

[0007] According to another aspect, a method of integrating electric vehicle battery packs into an integrated battery energy storage system is disclosed, the method including connecting a plurality of electric vehicle battery packs in a series / parallel arrangement, the series / parallel arrangement including a plurality of series strings of electric vehicle battery packs, each of the plurality of series strings of electric vehicle battery packs including at least two of the plurality of electric vehicle battery packs connected in series, the plurality of series strings of electric vehicle battery packs being connected in parallel, the connecting of the plurality of electric vehicle battery packs including one or more of the following steps: connecting electric vehicle battery packs having a lower voltage in series, connecting electric vehicle battery packs having a higher voltage in series, connecting electric vehicle battery packs having a majority voltage in series, and connecting electric vehicle battery packs within a programmed voltage connection window in parallel. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram illustrating a utility as part of an energy storage system in accordance with an exemplary embodiment. [Diagram 2] FIG. 1 illustrates a modified single-line electrical schematic diagram of an energy storage system in accordance with an illustrative embodiment. [Diagram 3] FIG. 1 illustrates a battery pack controller (BPC) with active balancer and smart combiner (SC) according to an exemplary embodiment. [Figure 4] FIG. 2 illustrates a mechanical layout of enclosure components in accordance with an illustrative embodiment. [Diagram 5] FIG. 1 illustrates an example of internal components of a battery pack for an electric vehicle (EV) according to an illustrative embodiment. [Figure 6] FIG. 1 illustrates an example of an energy storage system having three electric vehicle battery packs connected in series and eight such series-connected electric vehicle battery packs connected in parallel, according to an illustrative embodiment. [Figure 7] FIG. 2 illustrates an example of an external passive balancer for three electric vehicle battery packs arranged in series, according to an illustrative embodiment. [Figure 8] FIG. 2 illustrates an example of an external active balancer for three electric vehicle battery packs arranged in series, according to an illustrative embodiment. [Figure 9] FIG. 1 illustrates a method for integrating an electric vehicle battery pack into an integrated battery energy storage system. [Figure 10] FIG. 2 illustrates an exemplary hardware architecture for one embodiment of a computer system. [Figure 11] FIG. 1 is an exemplary block diagram of a battery pack interface unit that may be used in accordance with aspects of the present disclosure. [Figure 12] FIG. 2 is an example block diagram of a battery pack control unit that may be used in accordance with aspects of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] For the purpose of simplicity and exemplification, the principles of the embodiments are described mainly with reference to the examples thereof. In the following description, numerous specific details are set forth to provide a thorough understanding of the embodiments. However, it will be apparent to those skilled in the art that the embodiments may be practiced without being limited to these specific details. In some instances, well-known methods and structures have not been described in detail in order not to unnecessarily obscure the embodiments.

[0010] According to one aspect, an electric vehicle (EV) pack storage system (EPS) uses EV battery packs as an integrated functional unit or building block. In this case, multiple EV battery packs can be easily aggregated and function as a larger battery in an energy storage system. The batteries can be housed in a dedicated environmentally controlled enclosure in the original pack casing in which the batteries were installed in the electric vehicle. The dedicated environmentally controlled enclosure serves as an integrated EV pack storage unit, and the EV pack storage system serves as a subsystem building block in the overall energy storage system. The EV battery packs in the EV pack storage system can be electrically connected in series or parallel. Each of the series strings and parallel strings are protected with overcurrent devices. The EV pack storage system enclosure is designed to allow easy installation, removal, and replacement of the EV battery packs. Each battery pack and string can be monitored by a dedicated battery pack controller (BPC). The battery pack controller helps to ensure proper operating parameters and monitor the health of each EV battery pack. The Battery Pack Controller (BPC) can monitor the health of each EV battery pack by interfacing with the Battery Management System (BMS) integrated into the EV pack. The Battery Pack Controller manages the Smart Combiner (SC) to actively or passively balance the second-life batteries to effectively utilize the charge / discharge cycles of each pack, adjusting for capacity variations in each pack. The environment of the EV pack storage system enclosure is managed to maintain proper operating temperatures and detect hazards. The EV pack storage system operates within a larger energy storage system that also includes a power conversion system (PCS) and a supervisory control and data acquisition (SCADA) system. Multiple EV pack storage systems can operate together within the energy storage system. The energy storage system can be configured as DC-coupled or AC-coupled to the inverter.EV pack storage systems can be charged from on-site generation such as solar or wind power, or from power provided by an AC power system such as the grid. EV pack storage systems within an energy storage system can be located either before the meter (IFM) interconnected directly to the grid, or behind the meter (BTM) to offset customer load and demand.

[0011] According to one exemplary embodiment, an integrated system for deploying multiple second-life electric vehicle (EV) battery packs in an energy storage system (ESS) is disclosed.

[0012] In this disclosure, an EV Pack Storage System (EPS) is referred to as an integrated functional building block where multiple EV battery packs are easily aggregated to operate as a larger battery in an overall energy storage system. The configuration and functionality of the EV Pack Storage System may include the following: (1) The EV battery packs are utilized mechanically and electrically in the same manner as in their original vehicle application (first life) and incorporate a similar digital serial data link format and protocol as well as a battery pack Battery Management System (BMS). (2) The EV battery packs are electrically configured in a parallel arrangement and often arranged in series. Although EV battery packs may not be originally designed for use in series and / or parallel connections, this limitation is overcome by specific designs for mounting, communication, and interconnection. (3) Multiple EV battery packs are integrated into an environmentally controlled and monitored cabinet or enclosure that is not considered occupiable space as defined by building or fire codes, and a single enclosure or multiple enclosures can be integrated into the energy storage system. (4) The battery pack controller (BPC) is deployed as part of the EV pack storage system and integrates the communication and control required for multiple batteries to work together as a unified functional block. (5) The smart circuit combiner provides electrical balancing and overcurrent protection for all EV battery packs in the EV pack storage system.

[0013] FIG. 1 is a block diagram illustrating the utility of the present disclosure in a preferred embodiment as part of a grid-tied energy storage system. In an exemplary embodiment, an EV pack storage system (EPS) 100 can be implemented as part of an overall energy storage system (ESS). All bold lines 600 with arrows indicate power connections and possible power flow directions. All dashed lines 500 indicate bidirectional digital data bus connections.

[0014] The EV battery pack storage system (EPS) 100 includes a plurality of EV battery packs 110, designated in FIG. 1 as blocks 1, N-1, N to indicate any number N of identical EV battery packs. The EV battery pack 1 includes a battery 1.1 and a battery management system (BMS) 1.2. The batteries 1.1 to N.1 of the EV battery pack are connected in series with a nominal voltage that is a multiple of the nominal voltage of a single pack. The N EV battery packs 110 are connected in a series / parallel configuration or aggregated in a smart combiner 130 to function electrically as a larger battery in an overall energy storage system. The smart combiner 130 is connected to a bidirectional DC-to-DC (DCDC) converter 603. The DCDC converter 603 can provide optimal voltage matching between the EV battery packs and the inverter power conversion system (PCS) 605 as the maximum power point of the solar power generation unit 606 changes with temperature and load. A smart combiner (SC) 130 can be used to actively balance second-life batteries to accommodate variations in capacity of each pack and to effectively utilize the charge and discharge cycles of the individual packs.

[0015] When the overall system provides energy stored in the EV battery pack, for example, to the grid 610, DC power flows from the EV battery pack through the smart combiner 130 and through the DCDC converter 603. The DC power is then converted to AC power by the inverter power conversion system 605 and energy is provided to the grid 610. When power from the solar power generation unit 606 is available, for example, it can also flow through the inverter power conversion system 605 functioning as a DC-AC power converter and dump power to the grid 610. In this configuration, the total power provided to the grid 610 can be a combination of the power provided by the battery and the power provided by the solar power generation unit, for example.

[0016] According to an exemplary embodiment, when the overall system is providing energy to charge the EV battery packs 1-N, the inverter power conversion system 605 functions as an AC to DC power converter by providing AC power from the grid 610 and converting it to DC power. This DC power flows through the DCDC converter 603 and through the smart combiner 130 to all the EV battery packs 1-N. If power from the solar power generation unit 606 is available, it can be used to reduce the power required from the grid 610 to charge the EV battery packs 1-N, or if the available power from the solar power generation unit 606 is greater than the power required to charge these EV battery packs, the excess power can be provided to the grid 610. Some types of systems do not include the solar power generation unit 606 and therefore do not require the DCDC converter 603.

[0017] According to an exemplary embodiment, the Battery Management System (BMS) 1.2 monitors all cells in the EV battery pack 1, primarily for mismatched, undercharged, or overcharged cells in the series string. The Battery Management System may also monitor the pack voltage, current, and temperature. By monitoring and balancing mismatched cells and limiting current, voltage, and temperature, the usable life of the EV battery pack can be extended and safe operating parameters of the battery cells and battery pack can be ensured to avoid unsafe conditions. The Battery Pack Controller (BPC) 140 communicates with the individual EV battery packs 1-N via a digital data bus. The Supervisory Control and Data Acquisition (SCADA) 501 communicates with the Battery Pack Controller 140 to determine the state of charge, health, and overall availability of the aggregated EV battery packs. According to one exemplary embodiment, the supervisory control and data collection unit 501 receives top-level commands from the power system manager 503 via the Internet 502 and controls the operation of the overall energy storage system (EPS) 100, 200, 300, 400 (FIG. 2).

[0018] The SCADA 501 may also communicate with a cabinet control system 150. Within the EV pack storage system 100, the cabinet control system 150 may communicate with a thermal management block 151 and a hazard protection block 152. The thermal management block 151 provides air conditioning, dehumidification, ventilation, and air circulation as needed to maintain an optimal environment for the EV battery packs 1-N. The hazard detection block 152 monitors the environment inside the enclosure of the EV pack storage system 100, for example, smoke and over / under temperature conditions.

[0019] 2 is a modified single-line electrical diagram of an energy storage system according to an exemplary embodiment, showing power flow, however, this disclosure and description is not intended to limit the scope of the disclosure to a system having the number of elements and / or components described herein.

[0020] As shown in FIG. 2, the energy storage system may have, for example, four EV pack storage assemblies (EPS) 100, 200, 300, 400. Each EPS 100, 200, 300, 400 may be identical. However, each EPS is not identical and one or more of the EPSs 100, 200, 300, 400 may be modified. According to an exemplary embodiment, the EPS 100 includes 24 EV battery packs (EVBPs) designated 1-24. Within each EVBP are a number of battery modules connected in series or in series-parallel, designated as EVBP1 1.1 to EVBP24 24.1. There are also normally open contactors, which may be configured as one or more series-connected contactors, designated as EVBP1 1.3 to EVBP24 24.3. The EVBPs 1-24 may also include other power circuits, such as, but not limited to, pre-charge resistors, relays, fuses, etc. In this exemplary system, the EVBPs 1-24 are connected in a 2S12P configuration with pairs of EVBPs connected in series and 12 of these series strings connected in parallel. The series string pairs are 1 / 2, 3 / 4, 5 / 6, 7 / 8, 9 / 10, 11 / 12, 13 / 14, 15 / 16, 17 / 18, 19 / 20, 21 / 22, and 23 / 24. Each of the 12 series strings 1 / 2-23 / 24 are connected through fuses 101-112, respectively, in the smart combiner 130. The fuses 101-112 provide a second level of overcurrent protection to protect the EV batteries 1.1-24.1 from abnormal overcurrent. The fuses 101-112 can also prevent the contactors 1.3-24.3 from interrupting currents that exceed safe contactor limits. Contactors 1.3-24.3 can provide first stage overcurrent protection for currents below the ratings of fuses 101-112, as well as other circuit isolation and connection control functions. The output of smart combiner (SC) 130 is connected to switch 161 to connect or isolate the power circuit of EPS 100 from other components of the energy storage system. Fuse 162 protects the ampere capacity of the conductors and the interrupting capability of switch 161.According to one exemplary embodiment, the fuses of FIG. 2 may be replaced with circuit breakers or other overcurrent devices and systems.

[0021] In this system example, EPS100 and 200 are connected to a DCDC converter 603. EPS300 and 400 are connected to a DCDC converter 604. The DCDC converter 603 provides optimal voltage matching between the parallel-connected EPS100 and EPS200 and the inverter power conversion system (PCS) 605, and can provide optimal voltage matching when the maximum power point of the solar power generation unit 606 changes with temperature and irradiance. Both the DCDC converters 603 and 604 are capable of bidirectional power transfer, either charging or discharging the EV battery pack. The PCS 605 is also bidirectional in terms of power flow.

[0022] When the overall system is supplying, for example, energy stored in the batteries of EPS 100, 200, 300, and 400 to the grid 610 and / or local loads 607, DC power flows in parallel from EPS 100 and 200 through DCDC converter 603 and from EPS 300 and 400 through DCDC power converter 604. The DC power is then converted to AC power by PCS 605. The AC power then passes through distribution transformer 608, where the voltage can be increased to a more efficient distribution voltage level, and through revenue meter 609 before connecting to the grid 610. When power from solar power generation unit 606 is available and used, it also flows through PCS 605, which functions as a DC-AC power converter to supply power to the grid 610 and / or local loads 607. The total power delivered to the power grid 610 may be the sum of the power delivered from the battery and the power delivered from the solar power generation minus the power used by the local loads 607. Local loads may also be supported without being connected to the power grid 610, in which case the PCS 605 operates in a "standalone" AC voltage regulation mode.

[0023] When the integrated energy storage system is providing energy to charge the EV battery packs in the EPS 100, 200, 300, and 400, the PCS 605 functions as an AC-DC power converter by providing AC power from the grid 610 and converting the AC power to DC power. According to an exemplary embodiment, the DC power flows through the DC-DC converters 603 and 604 to charge the EV battery packs in the EPS 100, 200, 300, and 400. When power from the solar power generation unit 606 is available, it can be used to reduce the power required from the grid 610 to charge the EV battery packs, for example, or when the power available from the solar power generation unit 606 is greater than the power required to charge the EV battery packs and power the "behind the meter" local loads 607, the excess power can be sent to the grid 610.

[0024] According to an alternative embodiment shown in FIG. 2, the energy storage system may include one or more of a PCS 605, a DCDC converter 603, a transformer 608, and a power meter 609 as part of an integrated EPS 100.

[0025] FIG. 3 is a detailed view of the Battery Pack Controller (BPC) 140 and the smart combiner 130 shown in FIG. 1. Reference numeral 1 denotes a plurality of EV battery packs with EV battery pack (EVBP) 1 on top. Reference numeral 2 denotes a plurality of EV battery packs with EV battery pack (EVBP) 2 on top. In this embodiment of the EV Pack Storage System (EPS), EVBPs 1, 2 are electrically connected in series as a first series pair. Each series pair in the EPS communicates with one EV BMS Interface Board (EVIB) in the BPC 140. First, in the case of this top EVBP, BMS1.2 and BMS2.2 communicate with the EVIB 141 through digital data buses 504 and 505, respectively. The communication protocol is the same as that used in the manufacturer's electric vehicle application. In most cases, but not limited to, a Controller Area Network bus (CAN bus) is used. All other EVBP series pairs in the EPS communicate in a similar manner. The control circuit 142 aggregates data from all EVIBs in the BPC 140 and provides a Modbus® digital communication link 507 to the system control outside the EPS and a Modbus link 506 to the smart combiner 130. According to an exemplary embodiment, the Modbus digital communication link 507 communicates with the overall energy system SCADA (component 501 in FIG. 1 ) and reports the voltage, current, health, availability, and state of charge of the “combined” battery made up of the series / parallel connection of all the EV battery packs. The Modbus data link 506 connects the control circuit 142 to the control circuit 138, which actively controls the balancing of each EV battery pack in the series string.

[0026] According to an exemplary embodiment, balancing of each EV battery pack in the series string can be performed, for example, by monitoring the voltage, current, and temperature of each EV battery pack, and then transferring energy from the higher voltage pack to the lower voltage pack of the two packs in the series string. Using the example shown in FIG. 3, if EVBP1 has a higher voltage than EVBP2, semiconductor switch 132 is closed, current flows from battery 1.1 through inductor 137, semiconductor switch 132 is opened, current through inductor 137 flows through diode 135 to battery 2.1, completing one energy transfer cycle. This energy transfer cycle is repeated frequently for a time proportional to the desired energy transfer. If EVBP2 has a higher voltage than EVBP1, semiconductor switch 134 is closed, current flows from battery 2.1 through inductor 137, semiconductor switch 134 is opened, current through inductor 137 flows through diode 133 to battery 1.1, completing one energy transfer cycle.

[0027] FIG. 3 illustrates a method of balancing batteries in a series battery string, but does not limit the disclosure to any one method of balancing batteries or the number of EVBPs in a series string. In an exemplary embodiment, the energy storage system includes a battery pack controller (BPC) 140, an EV battery pack battery management system (1.2 and 2.2 in this example), a smart combiner 130, and an overall system controller interconnected and interoperable via a data link 507. Fuses 131 and 136 can be used to provide fault isolation between the series strings of EVBPs 1 and 2 and the parallel circuits of +bus 601 and -bus 602 of all series strings. In an exemplary embodiment, for example, all other series strings can be protected in a similar manner.

[0028] According to an exemplary embodiment, the energy storage system can include a weatherproof enclosure and a racking system for the EV battery pack in an EV pack storage system (EPS) box 100 in addition to each of the elements shown in FIG. 1. FIG. 4 shows an embodiment of the enclosure, which can include a fixed and removable exterior insulation panel 60. The enclosure 50 can be designed, for example, as a cabinet where the battery system and system controller are accessible from outside the enclosure, and the enclosure or cabinet is not an occupiable space as defined by building codes or fire codes. In an exemplary embodiment, the enclosure 50 is an outdoor rated enclosure that allows for outdoor deployment of the energy storage assembly.

[0029] According to an exemplary embodiment, the racking system 40 can be fabricated from structural steel and configured to hold the EV battery packs 110 (packs 1-24). For example, each pack 110 in this construction of the EV pack storage system (EPS) can weigh over 600 pounds. The side panels 60 of the enclosure 50 can be removed to allow easy access to and removal of the EV battery packs 1-24, for example, with a forklift. Additionally, the racking system 40 is designed to allow air to flow between the multiple EV battery packs. For example, each EV battery pack 110 can be electrically isolated from the racking system 40 by standoffs 30. The EV battery packs 110 can be cooled and heated by a temperature management system 151, for example, under the direction of a cabinet control system 150. The temperature management system 151 can include air conditioning, dehumidification, and other environmental controls as a means to extend the useful life of the EV battery packs 110. The hazard detection system 152 can provide an alert to the cabinet control system 150 when smoke, gas, or temperature conditions outside of the operating range are detected.

[0030] The functionality of the smart combiner 130 and the battery pack controller (BPC) 140 will be described with reference to the context of FIG. 1. The smart combiner 130, the battery pack controller 140, the cabinet control system 150, the thermal management system 151, and the hazard detection system 152 are not shown to scale or with distinctive physical features. One or more of the smart combiner 130, the battery pack controller 140, the cabinet control system 150, the thermal management system 151, and the hazard detection system 152 may be mounted in an EPS enclosure. According to an exemplary embodiment, the fixed and removable exterior panels 60 of the enclosure 50 may be insulated.

[0031] According to an exemplary embodiment, a system and method for improving yield from a plurality of electric vehicle (EV) battery packs 110 having varying states of health (SOH) is disclosed, which helps improve the storage and extraction of energy capacity from a plurality of electric vehicle (EV) battery pack systems 100, 200, 300, 400. In this manner, each of the EV battery packs 110 can be used as is without modification. Additionally, a battery cell module assembly (CMA) can be used that includes a plurality of cells that are assembled into a battery pack.

[0032] FIG. 5 illustrates the internal components of the EV battery pack 110. According to an exemplary embodiment, each battery pack 110 includes a dedicated battery management system (BMS) 1.2, e.g., a Lithium-Ion Battery Controller (LBC), provided by the manufacturer of the electric vehicle battery pack 110 or installed by an assembler if the electric vehicle battery pack is a battery cell module assembly (CMA). The BMS 1.2 can be configured to monitor the voltage and temperature of the individual cells, as well as the total current and voltage of the pack, and can provide a communication means (e.g., a Controller Area Network (CAN) bus) to report this information. The BMS 1.2 can also actively or passively maintain and balance the individual cells 720. In addition, as described above, the BMS 1.2 can also manage the cooling / heating of the battery pack 110. Each battery pack 110 can also include one or more contactors 710, 712, e.g., a positive contactor 710 and a negative contactor 712, that can be connected / disconnected under load. Each battery pack 110 may also include one or more prechargers 730 (power resistors 732 and relays 734), which can be used, for example, to limit current when a contactor is connecting / disconnecting the battery pack 110 under load. Additionally, each battery pack 110 includes all necessary electrical cables, cell interconnects, fuses, safety disconnects, connectors, components, and housings that make the battery relatively safe to access and easy to assemble into a usable battery (or battery storage system).

[0033] As described above, the battery cabinet 50 can provide a weather-protected and climate-controlled safe environment for the battery packs 110. The battery packs 110 can be loaded and secured within the cabinet 50 and wired in a series / parallel matrix to form a battery. The battery packs 110 can be wired in series up to the maximum operating voltage of the inverter / DC-DC converter, so that two or more battery packs can be wired in series (2s, 3s, 4s...Ns). According to an exemplary embodiment, any number of battery packs can be wired in parallel (2P, 3P, 4P...Np) to obtain a desired battery storage capacity. For example, FIG. 6 illustrates a battery matrix with eight series strings wired in parallel (e.g., a 3s8p matrix), each series string of batteries comprising three battery packs 110.

[0034] As shown in FIG. 6, each battery pack 110 can be individually wired and fused to form an intermediate rail 630, 632 (usually called a "center tap" in a 2s configuration) at each parallel battery connection location along with a positive rail 620 and a negative rail 622, resulting in Ns-1 intermediate rails. For example, for a series string with three battery packs, the number of intermediate rails 630, 632 is two. The intermediate rails 630, 632 can be used to balance the series voltage. In FIG. 6, the fuses 1-32 610 can be in a combiner box (or smart combiner) 130 (FIG. 3) mounted on the side of the cabinet 50, for example. For example, the fuses 1-32 640 can be sized to protect the wiring, and the fuses should be rated to be equal to or greater than the maximum charge / discharge current to which the battery packs 110 are exposed in the matrix configuration of the electric vehicle battery pack storage system 100. The combiner box 130 may also house the main disconnects and main fuses for the cabinet 50 .

[0035] According to one embodiment, each battery pack 110 may have an internal cell balancer, which may be either passive (resistive) or active (using inductors or capacitors to store and transfer charge). These internal balancers maintain the cell voltages, for example, to within a few millivolts (mV).

[0036] As shown in Figures 7 and 8, in addition to the internal cell balancers, the system can include an external string balancer system 700, 800. The external string balancer system 700, 800 is integrated into and / or attached to the combiner 130 and can be, for example, a passive balancer (resistive) 710 or an active balancer (using inductors or capacitors to store and transfer charge) 810. According to an exemplary embodiment, the external string balancer system 700, 800 can, for example, maintain the intermediate rails 630, 632 at the same voltage.

[0037] According to an exemplary embodiment, the battery pack controller (BPC) 140 may include two active components, a pack interface (PI) card 141 and a pack controller (PC) card (or control circuit) 142, as shown in FIG. 3. Additionally, the BPC 140 may include a passive backplane for communication between the pack interface card (PI) 141 and the pack controller (PC) card (or control circuit) 142. The BPC 140 may be configured to communicate directly with the battery pack 110 and may include input / output (I / O) for enabling and charging / discharging the battery pack 110. Each BPC 140 may communicate with and control one or more battery packs 110. The BPC 140 may have different communication methods and I / O as needed to interface with battery packs 110 of different makes. The BPC 140 may also simulate other components in the vehicle that may be required to enable the battery pack 110. For example, the BPC 140 can collect all available data from the battery pack 110 and store the data in a battery pack data structure. For example, the battery pack data structure can be unique for each manufacture of battery pack. According to one embodiment, the battery pack data structure can be populated with constant data that is sampled only once at startup, including, for example, the battery pack manufacturer, model, serial number, etc. Additionally, real-time data can be sampled at set intervals, such as, for example, every second, every two seconds, etc. The real-time data can include, for example, cell voltage, temperature, pack voltage, current, state of charge (SOC), state of health (SOH), status, trouble codes, etc.

[0038] According to an exemplary embodiment, the pack interface (PI) 141 can monitor pack data and can issue warnings or faults if values ​​fall outside expected ranges. For example, the battery pack 110 can be disabled by the BPC 140 if a critical fault occurs or communication is lost.

[0039] According to an exemplary embodiment, the BPC 140 communicates with each pack interface (e.g., Battery Management System (BMS) 1.2) over a passive backplane to obtain a generic subset of pack real-time data. The pack real-time data can be a condensed subset of data that can include minimum and / or maximum cell voltages, temperature and location, pack voltage, current, state of charge (SOC), state of health (SOH), status warnings and faults, etc. According to an example, the BPC 140 can monitor the pack data and also issue warnings and faults if values ​​fall outside expected ranges. If a critical fault occurs or communication is lost, the BPC 140 can disable the battery pack 110.

[0040] Additionally, the BPC 140 can communicate with a Supervisory Control and Data Acquisition (SCADA) system 501 via the BPC 140's native protocol, e.g., TCP / IP Modbus. The BPC 140 can also communicate and interface with other Battery Pack Controllers (BPCs) 140, e.g., pack interfaces of Battery Management System (BMS) 1.2 connected to the same inverter / DC-DC converter. The BPC 140 commands each pack interface to enable / disable to connect / disconnect the battery packs 110 from the battery matrix 100 as needed, e.g., as set in the matrix algorithm.

[0041] According to one embodiment, the EV battery pack 110 can be connected and disconnected under load. For example, a pre-charge resistor 730 (FIG. 5) can be used to limit the current before the pack 110 is connected or disconnected. When the pack interface 141 receives a command to connect the pack 110, the negative contactor 712 is closed, then the pre-charge resistor relay 730 is closed, then the positive contactor 710 is closed, and finally the pre-charge resistor relay 730 is opened. When the pack interface 141 receives a command to disconnect the pack 110, the pre-charge resistor relay 730 is closed, then the positive contactor 710 is opened, then the pre-charge resistor relay 730 is opened, and finally the negative contactor 712 is opened.

[0042] According to an exemplary embodiment, the battery pack controller (BPC) 140 can command to connect the pack 110 with the lowest voltage (e.g., to start charging), to connect the pack 110 with the highest voltage (e.g., to start discharging), or to connect multiple packs 110 (e.g., to connect as many packs 110 as possible for charging or discharging). When the pack 110 with the lowest voltage is commanded to be connected, a matrix algorithm is configured to locate the lowest voltage pack 110 and form a series string of battery packs 110. A series string of battery packs can be commanded to connect, e.g., two battery packs in series (2s), three battery packs in series (3s), four battery packs in series (4s), ... Ns packs 110 in series, which becomes the first connected string if successful. If one or more of the battery packs fails, another attempt is made using the next lowest voltage non-failed pack. The SCADA system 501 can then charge the connected string, where the charging current is limited to the maximum programmed pack current.

[0043] According to an exemplary embodiment, as the first series string begins to charge, the voltage of the connected packs 110 begins to rise. If the voltage of one or more of the packs 110 in the first series string is within the programmed voltage connection window of the disconnected pack 110, the BPC 140 can enable one or more of those packs 110 to connect in parallel with the packs in the first series string whose voltage is found to be within the programmed voltage connection window of the disconnected pack. The pack interface 141 then connects the packs 110 as directed. As the packs 110 charge and their voltage increases, more of the disconnected packs 110 match the programmed voltage connection window and connect. As more packs 110 connect, the BPC 140 adjusts the charging current of the SCADA 501 to stay below the programmed pack current maximum. Eventually, according to an exemplary embodiment, all of the non-faulty packs 110 in, for example, the matrix 600 are connected.

[0044] According to an exemplary embodiment, the battery pack controller (BPC) 140 can command the pack 110 with the highest voltage to be connected, and a matrix algorithm will search for the pack with the highest voltage to create a series string. For example, the series string can be two voltage packs in series (2s), three voltage packs in series (3s), four voltage packs in series (4s)...Ns packs 110. The series string of battery packs 110 can be commanded or programmed to connect, and if successful, this will be the first connected string of packs with higher voltages. If one or more of the packs with higher voltages is faulty, another attempt is made with a non-faulty pack 110 with the next higher voltage from the higher voltage pack 110. The SCADA system 501 can then enable discharging of the connected series string, and the discharge current is limited to the maximum programmed pack current.

[0045] According to an exemplary embodiment, as the first string of packs 110 with higher voltages begins to discharge, the voltages of the connected packs 110 begin to drop. When the voltage of one or more of the battery packs 110 is within the programmed voltage connection window of the disconnected packs 110, the BPC 140 allows one or more packs 110 with voltages within the programmed voltage connection window to be connected. The BPC 140 then connects the battery packs 110 as instructed. As the battery packs 110 discharge and the voltage drops, more disconnected battery packs 110 match the programmed voltage connection window and are connected. As more battery packs are connected, the BPC 140 adjusts the discharge current of the SCADA 501 to stay below the programmed pack current maximum. Eventually, all non-faulty packs in the matrix 600 can be connected, according to an exemplary embodiment.

[0046] According to an exemplary embodiment, when the matrix algorithm is instructed to connect a plurality of battery packs 110 that form a majority of the battery packs 110 that are within the programmed voltage connection window, it can calculate a histogram of the plurality of battery packs 110 binned by the programmed voltage connection window (e.g., a plurality of battery packs 110 having a majority of voltages that are within the programmed voltage connection window). The matrix algorithm can then create one or more series strings of battery packs having a majority of voltages, each of which may have two or more battery packs in series (2s), three or more battery packs in series (3s), four or more battery packs in series (4s),...Ns packs, and any number of battery packs may be connected, with the battery pack 100 being the first connected string if successful. If one or more packs are faulty, a retry is made with other binned non-faulty packs 110. The remaining packs 110 within the programmed voltage connection window are instructed to connect.

[0047] The SCADA system 501 can then enable charging or discharging of the connected series strings, with the charge / discharge current limited to the programmed pack current maximum. If the voltage of any packs falls within the programmed voltage connection window of the disconnected pack, the pack controller allows those packs to be connected. The pack interface then connects the packs 110 as directed. As more packs are connected, the pack controller adjusts the SCADA 501 charge current to be below the programmed pack current maximum. Additionally, if the battery packs with the majority voltage (i.e., the majority of the packs are within the determined voltage range) are connected in series, the series strings of electric vehicle battery packs whose electric vehicle battery packs are within the programmed voltage connection window can be connected in parallel.

[0048] According to an exemplary embodiment, due to variations in battery pack state of health (SOH), capacity, and individual cell balance, some battery packs 110 will be fully charged or fully discharged before other battery packs. For example, when a battery pack 110 reaches a programmed maximum cell voltage and / or maximum state of charge (SOC), it will be disconnected to allow other battery packs 110 in the system to be fully charged. Before disconnecting the battery pack 110, the SCADA 501 charging current is reduced as necessary to be below the programmed maximum pack current. During charging, the battery packs 110 will eventually be disconnected down to the programmed minimum number of connected series strings. The minimum number of connected strings is determined by the minimum load of the inverter / DC-DC converter. When discharging is initiated, battery packs within the programmed voltage connection window are instructed to connect and the discharge current is limited to the programmed maximum pack current.

[0049] According to an exemplary embodiment, when an EV battery pack 100, 200, 300, 400 reaches a programmed cell voltage minimum and / or state of charge (SOC) minimum, it is disconnected to allow other battery packs 110 in the system to fully discharge. Before disconnecting the pack 110, the SCADA 501 discharge current is reduced as necessary to be below the programmed pack current maximum. During discharge, the battery pack 110 is eventually disconnected down to the programmed minimum number of strings connected. For example, the minimum number of strings connected is determined by the minimum load of the inverter / DC-DC converter. When charging is initiated, battery packs 110 within the programmed voltage connection window are commanded to connect and the discharge charge is limited to the programmed pack current maximum.

[0050] 11 and 12 are alternative block diagrams illustrating various further aspects of the disclosure, which may represent variations of the aspects of the disclosure presented above. FIG. 11 illustrates an example of a battery pack interface (BPI) 1100 that may be incorporated into a battery pack controller (BPC) 140 and / or an EV BMS interface board 141 that may form part of the BPC 140. In FIG. 11, a microcontroller 1101 may be programmed to perform the control functions of the battery pack interface, as described above. Control and other information may be communicated via the CAN bus described above. To this end, the BPI 1100 may comprise CAN transceivers 1102 and 1104. The CAN transceiver 1102 may facilitate communication between the microcontroller 1101 and a control interface 1103 (which may be an interface to the CCS 150). The CAN transceiver 1104 is isolated from the microcontroller 1101 by a galvanic isolator 1105 and can facilitate communication of control information between the microcontroller and a battery management system (BMS) and cell monitor 1.2 of one or more battery packs 1,...,N. Other signals, labeled SOURCE1,...,SOURCE6, INPUT1, INPUT2, SINK1, SINK2 and generally indicated by elements 1106 and 1107, can be used to transmit information between one or more battery packs 1...N. Respective optical isolators can be provided at respective connections between the battery packs 1,...,N and respective ports of the microcontroller 1101. The BPI can also include one or more power sources 1108,1109, which may be in the form of DC-DC converters, to provide power to the microcontroller 1101 and / or other devices. An auxiliary power unit 1110 can provide input to the power sources 1108,1109.

[0051] FIG. 12 illustrates an example of a portion of EPS 100 according to further aspects of the disclosure. System 1200 may include elements corresponding to elements / functions 1100(1,...,N), 130, and 140, among others. Elements 1201-1 to 1201-N represent respective battery pack controllers, each of which may include BPI 1100 as well as elements of BPC 140. Elements 1201-1 to 1201-N may include respective optical isolators 1202-1, 1205-1,...,1202-N,1205-N that may couple signals between battery pack controllers 1201-1,...,1201-N and battery packs 1,...,N. As also illustrated in FIG. 11, galvanic isolators 1203-1,...,1203-N may be for control signals transmitted over the CAN interface. Elements 1204-1,...,1204-N correspond to electrically isolated power sources (1108 or 1109 depending on the wattage required) capable of powering battery packs 1,...,N. Element 130 again corresponds to smart combiner 130, the variant of Figure 12 using resistive balancing instead of inductive balancing as shown in Figure 3.

[0052] Use of the isolation components in Figures 11 and 12 may improve operation of the overall system. In particular, the galvanic and optical isolation shown in these figures may help, for example, to ensure that each BMS 1.2 of battery packs 1,...,N "sees" only the voltage of its respective battery pack 1,...,N, thereby enabling it to have improved control functions than would be possible without the isolation.

[0053] FIG 9 illustrates a method 900 for integrating electric vehicle battery packs into an integrated battery energy storage system. As shown in FIG 9, the method includes connecting a plurality of electric vehicle battery packs in a series / parallel arrangement, the series / parallel arrangement including a plurality of series strings of electric vehicle battery packs, each of the plurality of series strings of electric vehicle battery packs including at least two of the plurality of electric vehicle battery packs connected in series, the plurality of series strings of electric vehicle battery packs being connected in parallel (910). Furthermore, connecting the plurality of electric vehicle battery packs includes one or more of the following steps: connecting electric vehicle battery packs having lower voltages in series, connecting electric vehicle battery packs having higher voltages in series, connecting electric vehicle battery packs having a majority voltage in series, and connecting other electric vehicle battery packs in parallel within a programmed voltage connection window (920).

[0054] According to an exemplary embodiment, the method may further include connecting the electric vehicle battery packs having a lower voltage in series at least as a low voltage series string and charging the low voltage series string to a programmed maximum pack current. Additionally, the method may further include, if one or more of the electric vehicle battery packs having a lower voltage are faulty, connecting one or more electric vehicle battery packs having the next lowest voltage to the low voltage series string in place of the one or more electric vehicle batteries. The method may also include charging one or more of the electric vehicle battery packs connected to the low voltage series string to a programmed maximum pack current of the one or more disconnected electric vehicle battery packs, connecting one or more of the electric vehicle battery packs within the programmed voltage connection window of the disconnected electric vehicle battery pack in parallel, and connecting one or more of the disconnected electric vehicle battery packs within the programmed voltage connection window of the disconnected electric vehicle battery pack together into one or more series strings.

[0055] According to another exemplary embodiment, the method includes connecting electric vehicle battery packs having a higher voltage in series as a high voltage series string and discharging the high voltage series string to a programmed maximum pack current. Furthermore, if one or more of the higher voltage electric vehicle battery packs are faulty, the method further includes connecting one or more electric vehicle battery packs having the next highest voltage to the high voltage series string in place of the faulty one or more higher voltage electric vehicle battery packs. The method also includes discharging one or more of the electric vehicle battery packs connected in the high voltage series string to a programmed maximum pack current of the one or more disconnected electric vehicle battery packs, connecting one or more of the electric vehicle battery packs within the programmed voltage connection window of the disconnected electric vehicle battery pack in parallel, and connecting one or more of the disconnected electric vehicle battery packs within the programmed voltage connection window of the disconnected electric vehicle battery pack together into one or more series strings.

[0056] According to an exemplary embodiment, the method may further include connecting electric vehicle automobile battery packs in series / parallel within a programmed voltage connection window by calculating a histogram of electric vehicle battery packs with binning determined by the programmed voltage window, and limiting the charge or discharge current of the series connected electric vehicle battery packs to a maximum programmed pack current. Additionally, the method may further include disconnecting the charged electric vehicle battery pack from the series connected electric vehicle battery pack having the lower voltage at the end of a charge cycle based on one or more of the state of charge (SOC) or cell voltage of the charged electric vehicle battery pack, and disconnecting the discharged electric vehicle battery pack from the series connected electric vehicle battery pack having the higher voltage at the end of a discharge cycle based on the state of charge (SOC) or cell voltage of the discharged electric vehicle battery pack.

[0057] 10 illustrates a representative computer system 1000 in which embodiments of the present disclosure, or portions thereof, may be implemented as computer readable code executed on hardware. For example, the BPC 140, SCADA 501, and power system manager 503 may be implemented in whole or in part by the computer system 1000 using hardware, software executed on the hardware, firmware, non-transitory computer readable media having stored instructions, or combinations thereof, or may be implemented in one or more computer systems or other processing systems. The hardware, software executed on the hardware, or any combination thereof may embody modules and components used to implement the methods and steps in the presently described methods and systems.

[0058] Where programmable logic is used, such logic may be executed on commercially available processing platforms that are configured by executable software code to become special purpose computers or special purpose devices (e.g., programmable logic arrays, application specific integrated circuits, etc.). Those skilled in the art will appreciate that embodiments of the disclosed subject matter may be implemented in a variety of computer system configurations, including multi-core multiprocessor systems, minicomputers, mainframe computers, computers linked or clustered with distributed functionality, as well as pervasive or small computers that may be incorporated into virtually any device. For example, at least one processor device and memory may be used to implement the embodiments described above.

[0059] A processor unit or device described herein may be a single processor, multiple processors, or a combination thereof. A processor device may have one or more processor "cores." As described herein, the terms "computer program medium," "non-transitory computer-readable medium," and "computer usable medium" are generally used to refer to tangible media, such as removable storage unit 1018, removable storage unit 1022, and a hard disk installed in hard disk drive 1012.

[0060] Various embodiments of the present disclosure are described in terms of this representative computer system 1000. After reading this description, it will become apparent to one of ordinary skill in the relevant art how to implement the present disclosure using other computer systems and / or computer architectures. Although operations may be described as sequential processes, in reality some operations may be performed in parallel, concurrently, and / or in distributed environments, with program code stored locally or remotely for access by single or multi-processor machines. Furthermore, in some embodiments, the order of operations may be rearranged without departing from the spirit of the disclosed subject matter.

[0061] The processor device 1004 may be a processor device specially configured to perform the functions described herein. The processor device 1004 may be connected to a communication infrastructure 1006, such as a bus, a message queue, a network, a multi-core message passing scheme, or the like. The network may be any network suitable for performing the functions disclosed herein, and may include a local area network (LAN), a wide area network (WAN), a wireless network (e.g., Wi-Fi), a mobile communication network, a satellite network, the Internet, fiber optics, coaxial cable, infrared, radio frequency (RF), or any combination thereof. Other suitable network types and configurations will be apparent to those skilled in the relevant art. The computer system 1000 may also include a main memory 1008 (e.g., random access memory, read-only memory, etc.) and may also include a secondary memory 1010. The secondary memory 1010 may include a hard disk drive 1012 and a removable storage drive 1014, such as a floppy disk drive, a magnetic tape drive, an optical disk drive, a flash memory, or the like.

[0062] The removable storage drive 1014 can read from and / or write to the removable storage unit 1018 in a well-known manner. The removable storage unit 1018 can include a removable storage medium that is read from and written to by the removable storage drive 1014. For example, if the removable storage drive 1014 is a floppy disk drive or a universal serial bus port, the removable storage unit 1018 can be a floppy disk or a portable flash drive, respectively. In one embodiment, the removable storage unit 1018 can be a non-transitory computer readable recording medium.

[0063] In some embodiments, the secondary memory 1010 may include alternative means for allowing computer programs or other instructions to be loaded into the computer system 1000, such as removable storage units 1022 and interfaces 1020. Examples of such means may include program cartridges and cartridge interfaces (e.g., such as those found in video game systems), removable memory chips (e.g., EEPROMs, PROMs, etc.) and associated sockets, as well as other removable storage units 1022 and interfaces 1020 that will be apparent to those skilled in the relevant art.

[0064] Data stored in computer system 1000 (e.g., in main memory 1008 and / or secondary memory 1010) may be stored on any type of suitable computer-readable medium, such as optical storage (e.g., compact disc, digital versatile disc (DVD), Blu-ray disc, etc.), or magnetic storage (e.g., hard disk drive). The data may be organized in any type of suitable database configuration, such as a relational database, a structured query language (SQL) database, a distributed database, an object database, etc. Suitable configurations and storage types will be apparent to those skilled in the relevant art.

[0065] Computer system 1000 may also include a communications interface 1024. Communications interface 1024 may be configured to allow software and data to be transferred between computer system 1000 and external devices. Exemplary communications interface 1024 may include a modem, a network interface (e.g., an Ethernet card), a communications port, a PCMCIA slot and card, and the like. The software and data transferred via communications interface 1024 may be in the form of electronic, electromagnetic, optical, or other signals that would be apparent to one of ordinary skill in the relevant art. The signals may travel over communications path 1026, which is configured to transmit the signals and may be implemented using wire, cable, fiber optics, a telephone line, a cellular phone link, a radio frequency link, and the like.

[0066] The computer system 1000 may further include a display interface 1002. The display interface 1002 may be configured to allow data to be transferred between the computer system 1000 and an external display 1030. Exemplary display interfaces 1002 may include a high definition multimedia interface (HDMI), a digital visual interface (DVI), a video graphics array (VGA), etc. The display 1030 may be any suitable type of display for displaying data transmitted via the display interface 1002 of the computer system 1000, including a cathode ray tube (CRT) display, a liquid crystal display (LCD), a light emitting diode (LED) display, a capacitive touch display, a thin film transistor (TFT) display, etc.

[0067] Computer program medium and computer usable medium may refer to memory, such as main memory 1008 and secondary memory 1010, which may be memory semiconductors (e.g., DRAM, etc.). These computer program products may be means for providing software to the computer system 1000. Computer programs (e.g., computer control logic) may be stored in the main memory 1008 and / or the secondary memory 1010. Computer programs may also be received via the communication interface 1024. Such computer programs, when executed, may enable the computer system 1000 to perform the methods described herein. In particular, computer programs, when executed, may enable the processor device 1004 to perform the methods described herein and illustrated in Figures 1-9. Thus, such computer programs may represent a controller of the computer system 1000. When the present disclosure is implemented using software executed on hardware, the software may be stored in the computer program product and loaded into the computer system 1000 using the removable storage drive 1014, the interface 1020, and the hard disk drive 1012, or using the communication interface 1024.

[0068] The processor device 1004 may be comprised of one or more modules or engines configured to perform the functions of the computer system 1000. Each module or engine may be implemented using hardware, and in some cases may also utilize software executed on the hardware, such as corresponding to program code and / or programs stored in the main memory 1008 or the secondary memory 1010. In such a case, the program code may be compiled by the processor device 1004 (e.g., by a compilation module or engine) prior to execution by the hardware of the computer system 1000. For example, the program code may be source code written in a programming language that is translated into a lower level language, such as assembly language or machine code, for execution by the processor device 1004 and / or any additional hardware components of the computer system 1000. The process of compilation may include the use of lexical analysis, preprocessing, syntax analysis, semantic analysis, syntax-directed translation, code generation, code optimization, and any other techniques that may be suitable for translating the program code into a lower level language suitable for controlling the computer system 1000 to perform the functions disclosed herein. As a result of such processing, computer system 1000 becomes a specially configured computer system 1000 that is uniquely programmed to perform the functions described above, as will be apparent to those skilled in the relevant art.

[0069] Technology consistent with the present disclosure provides, among other things, a system and method for energy storage using second-life electric vehicle batteries. While various exemplary embodiments of the disclosed system and method have been described, it should be understood that they are presented for purposes of illustration only, and not limitation. The exemplary embodiments described above are not intended to be exhaustive or to limit the disclosure to the precise form disclosed. Various modifications and variations are possible in light of the above teachings or may be acquired from practice of the disclosure without departing from the breadth or scope of the disclosure.

Claims

1. 1. An integrated battery energy storage system, comprising: a plurality of electric vehicle battery packs; and a computer system including a processor, the processor comprising: configured to couple the plurality of electric vehicle battery packs in a series / parallel arrangement, the series / parallel arrangement including a plurality of series strings of electric vehicle battery packs, each of the plurality of series strings of electric vehicle battery packs including at least two of the plurality of electric vehicle battery packs coupled in series, the plurality of series strings of electric vehicle battery packs being connected in parallel; the connection of the plurality of electric vehicle battery packs includes one or more of a series connection of electric vehicle battery packs having a lower voltage, a series connection of electric vehicle battery packs having a higher voltage, a series connection of electric vehicle battery packs having a majority voltage, and a parallel connection of electric vehicle battery packs within a programmed voltage connection window, integrated battery energy storage system.

2. The processor, connecting the lower voltage electric vehicle battery packs in series as at least a low voltage series string; 10. The integrated battery energy storage system of claim 1 configured to charge said low voltage series string to a programmed maximum pack current.

3. If one or more of the electric vehicle battery packs having the lower voltage is defective, The processor, 3. The integrated battery energy storage system of claim 2, configured to connect one or more electric vehicle battery packs having a next lowest voltage to the low voltage series string in place of the failed one or more lower voltage electric vehicle battery packs.

4. The processor, charging one or more of the electric vehicle battery packs connected to the low voltage series string to a maximum programmed pack current of one or more disconnected electric vehicle battery packs; connecting in parallel one or more of the electric vehicle battery packs within a programmed voltage connection window of the disconnected electric vehicle battery packs; 3. The integrated battery energy storage system of claim 2, configured to connect one or more of the disconnected electric vehicle battery packs that are within the programmed voltage connection window of the disconnected electric vehicle battery packs together in one or more series strings.

5. The processor, connecting the higher voltage electric vehicle battery packs in series as a high voltage series string; 10. The integrated battery energy storage system of claim 1 configured to discharge said high voltage series string to a programmed maximum pack current.

6. If one or more of the higher voltage electric vehicle battery packs is faulty, the processor:

6. The integrated battery energy storage system of claim 5, configured to connect one or more electric vehicle battery packs having a next highest voltage to the high voltage series string in place of the failed one or more higher voltage electric vehicle battery packs.

7. The processor, discharging one or more of the electric vehicle battery packs connected to the high voltage series string to a maximum programmed pack current of one or more disconnected electric vehicle battery packs; connecting one or more of the electric vehicle battery packs in parallel within a programmed voltage connection window of the disconnected electric vehicle battery pack; 6. The integrated battery energy storage system of claim 5, configured to connect one or more of the disconnected electric vehicle battery packs that are within the programmed voltage connection window of the disconnected electric vehicle battery packs together in one or more series strings.

8. The processor, connecting the electric vehicle battery packs in series / parallel within the programmed voltage connection window by calculating a histogram of the electric vehicle battery packs binned by the programmed voltage range; 13. The integrated battery energy storage system of claim 1 configured to limit the charge or discharge current of the series connected electric vehicle battery packs to a programmed maximum pack current.

9. The processor, disconnecting the charged electric vehicle battery pack from the series-connected electric vehicle battery pack having the lower voltage at the end of a charging cycle based on one or more of a state of charge (SOC) or cell voltage of the charged electric vehicle battery pack; 10. The integrated battery energy storage system of claim 1 configured to disconnect a discharged electric vehicle battery pack from the higher voltage series connected electric vehicle battery pack at an end of a discharge cycle based on a state of charge (SOC) or cell voltage of the discharged electric vehicle battery pack.

10. an external cell balancer configured to maintain one or more intermediate rails of the electric vehicle battery packs coupled in the series / parallel arrangement at the same voltage; a circuit combiner including an overcurrent device connected in series with each of the plurality of series strings; 10. The integrated battery energy storage system of claim 1, further comprising: a smart combiner including a plurality of DC-DC converters configured to balance two or more electric vehicle battery packs in a common series string by transferring energy from one electric vehicle battery pack to another electric vehicle battery pack in the common series string or by transferring energy from another electric vehicle battery pack to an electric vehicle battery pack in the common series string.

11. a battery pack controller configured to communicate with and control a battery management system in each of the plurality of electric vehicle battery packs; 13. The integrated battery energy storage system of claim 1, further comprising: a bi-directional power converter configured to convert DC electric vehicle battery pack power to AC grid power or convert AC grid power to charge the DC electric vehicle battery pack.

12. 1. A method for integrating an electric vehicle battery pack into an integrated battery energy storage system, the method comprising: connecting a plurality of electric vehicle battery packs in a series / parallel arrangement, the series / parallel arrangement including a plurality of series strings of electric vehicle battery packs, each of the plurality of series strings of electric vehicle battery packs including at least two of the plurality of electric vehicle battery packs connected in series, the plurality of series strings of electric vehicle battery packs being connected in parallel; The method, wherein the coupling of the plurality of electric vehicle battery packs includes one or more of the following steps: connecting electric vehicle battery packs having lower voltages in series, connecting electric vehicle battery packs having higher voltages in series, connecting electric vehicle battery packs having a majority voltage in series, and connecting electric vehicle battery packs within a programmed voltage connection window in parallel.

13. connecting the low voltage electric vehicle battery packs in series as at least a low voltage series string; charging the low voltage series string to a programmed maximum pack current; The method of claim 12 further comprising:

14. If one or more of the electric vehicle battery packs having the lower voltage is defective, 14. The method of claim 13, further comprising the step of connecting one or more electric vehicle battery packs having a next lowest voltage to the low voltage series string in place of the defective one or more lower voltage electric vehicle battery packs.

15. charging one or more of the electric vehicle battery packs connected to the low voltage series string to a maximum programmed pack current of one or more disconnected electric vehicle battery packs; connecting one or more of the disconnected electric vehicle battery packs in parallel within a programmed voltage connection window of the disconnected electric vehicle battery pack; 14. The method of claim 13, further comprising: connecting one or more of the disconnected electric vehicle battery packs that are within the programmed voltage connection window of the disconnected electric vehicle battery packs together into one or more series strings.

16. connecting the higher voltage electric vehicle battery packs in series as a high voltage series string; 13. The method of claim 12, further comprising discharging the high voltage series string to a programmed maximum pack current.

17. If one or more of the higher voltage electric vehicle battery packs is defective, 17. The method of claim 16, further comprising the step of connecting one or more electric vehicle battery packs having a next highest voltage to the high voltage series string in place of the failed one or more higher voltage electric vehicle battery packs.

18. discharging one or more of the electric vehicle battery packs connected to the high voltage series string to a maximum programmed pack current of one or more disconnected electric vehicle battery packs; connecting one or more of the disconnected electric vehicle battery packs in parallel within a programmed voltage connection window of the disconnected electric vehicle battery pack; 17. The method of claim 16, further comprising: connecting one or more of the disconnected electric vehicle battery packs that are within the programmed voltage connection window of the disconnected electric vehicle battery packs together into one or more series strings.

19. connecting the electric vehicle battery packs in series / parallel within the programmed voltage connection window by calculating a histogram of the electric vehicle battery packs binned by the programmed voltage range; 13. The method of claim 12, further comprising the step of: limiting the charge or discharge current of the series connected electric vehicle battery packs to a programmed maximum pack current.

20. disconnecting the charged electric vehicle battery pack from the series-connected electric vehicle battery pack having the lower voltage at the end of a charging cycle based on one or more of a state of charge (SOC) or cell voltage of the charged electric vehicle battery pack; 13. The method of claim 12, further comprising: disconnecting the discharged electric vehicle battery pack from the higher voltage series connected electric vehicle battery pack at the end of a discharge cycle based on a state of charge (SOC) or cell voltage of the discharged electric vehicle battery pack.

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