System and method for diagnosing and evaluating battery status

Abstract

The invention relates to a system and a method for diagnosing and evaluating the state of a battery. A system for diagnosing and evaluating the state of a battery of an electric vehicle includes: a charging / discharging system that provides a direct high-voltage path for simultaneous charging and discharging between a diagnosis target vehicle (EV1) and a center vehicle (EV2); the diagnostic device obtains vehicle data corresponding to each of charging and discharging from the EV1 through diagnostic communication, and diagnoses and evaluates a battery state of the EV1 based on the vehicle data. Specifically, after the EV2 battery is charged by the energy released from the EV1 battery through the charge / discharge system, the EV1 battery is charged by the energy released from the EV2 battery through the charge / discharge system.

Description

[0001] Cross-references to related applications

[0002] This application claims priority and benefit to Korean Patent Application No. 10-2024-0131018, filed with the Korean Intellectual Property Office on September 26, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to a vehicle diagnostic device, a system including the vehicle diagnostic device, and a method for diagnosing a vehicle. More specifically, this invention relates to a technique for diagnosing and evaluating the battery status of an electric vehicle (EV) via an electric vehicle-to-electric vehicle (EV-to-EV) power transmission system. Background Technology

[0004] With the recent increase in the number of EV users, the State of Health (SOH) and abnormal condition assessment of electric vehicle batteries have become increasingly important in high-voltage battery status certification, EV pre-owned vehicle certification, and remanufacturing. SOH indicates how the battery's current performance compares to its initial performance and serves as an indicator of remaining battery life and current state of performance.

[0005] State of Charge (SOC) refers to the amount of electricity that can be used from a battery cell, expressed as the ratio of the current charge to the battery's initial maximum usable charge at the time of manufacture. In other words, SOC indicates the battery's remaining energy or charge level, expressed as a percentage (%) of full battery capacity. SOC reflects the overall health of the battery and its aging over time.

[0006] In order to assess SOH and abnormal conditions, the battery needs to be charged and discharged from an appropriate low SOC to a high SOC.

[0007] When a vehicle's battery enters a battery state assessment center and its SOC (State of Charge) is not lower than a specified reference value (e.g., a predetermined low SOC value), the battery needs to be discharged to the reference value (e.g., the predetermined low SOC value). In related technologies, the battery's SOC is reduced below the reference value using conventional methods such as highway driving and heater discharge. However, the disadvantage of conventional methods is low discharge capacity, resulting in a large amount of working time and a long discharge time. Specifically, because existing conventional discharge schemes convert electrical energy into kinetic energy and / or heat energy, they not only waste energy during the discharge process but also require a large amount of electrical energy to recharge the battery after discharge.

[0008] While using a dedicated charger / discharger to replace the traditional discharging solution can shorten the discharging time due to higher power consumption, the increased form factor requires high installation costs and a large amount of space, and the dedicated charger / discharger driven for discharging incurs separate electricity costs.

[0009] The statements in this background section are only to provide background information related to the present invention and do not constitute prior art. Summary of the Invention

[0010] The present invention aims to solve the above-mentioned problems while maintaining the advantages. Specifically, the present invention provides a diagnostic and assessment technology for the state of electric vehicle (EV) batteries, which can minimize the time and energy waste required for discharge without utilizing a dedicated charger / discharger.

[0011] One aspect of the present invention provides a vehicle control device for diagnosing and assessing battery status, a system including the vehicle control device, and a method for diagnosing and assessing battery status.

[0012] Another aspect of the present invention provides an apparatus for diagnosing and evaluating the state of an EV battery via an electric vehicle-to-electric vehicle (EV-to-EV) power transmission system, a system including the apparatus, and a method for diagnosing and evaluating the state of an EV battery via an EV-to-EV power transmission system.

[0013] The technical problems to be solved by the present invention are not limited to those described above, and those skilled in the art to which the present invention pertains should clearly understand any other technical problems not mentioned herein based on the following description.

[0014] According to one aspect of the invention, a system for diagnosing and evaluating the state of an electric vehicle battery includes a charging and discharging system (which may also be referred to herein as a "charging / discharging system") and a diagnostic device. The charging / discharging system establishes a direct high-voltage path for charging and discharging between the target vehicle (EV1) and a central vehicle (EV2). The diagnostic device obtains vehicle data corresponding to each charging and discharging cycle from EV1 via diagnostic communication and diagnoses and evaluates the state of the EV1 battery based on the vehicle data. After energy released from the EV1 battery charges the EV2 battery through the charging / discharging system, energy released from the EV2 battery charges the EV1 battery through the charging / discharging system.

[0015] According to the implementation plan, the diagnostic device or charging / discharging system can determine the start time of the EV1 battery's discharge and charging sequence based on the EV1 battery's current state of charge (SOC).

[0016] According to the implementation plan, the charging / discharging system can receive information about the current SOC of the EV1 battery from the diagnostic device to determine the start time of the discharge and charging sequence of the EV1 battery, and the diagnostic device can obtain information about the current SOC of the EV1 battery from the EV1 through diagnostic communication.

[0017] According to the implementation scheme, the vehicle data corresponding to each charging and discharging may include at least one of the EV1 battery's SOC, maximum voltage (Vmax), or minimum voltage (Vmin).

[0018] According to the implementation plan, the charging / discharging system can compare vehicle data with reference values ​​corresponding to the current state of the battery to determine the time point for the termination of charging and discharging, and the current state can include both charging state and discharging state.

[0019] According to the implementation scheme, when the current state is a charging state, or based on the current state being a charging state, and based on the SOC being greater than or equal to a predetermined charging termination SOC upper limit, or Vmax being greater than or equal to a predetermined charging termination battery cell voltage upper limit and Vmin being greater than or equal to a predetermined charging termination battery cell voltage lower limit, the charging / discharging system can determine charging termination. And when the current state is a discharging state, or based on the current state being a discharging state, and based on the SOC being less than or equal to a predetermined discharging termination SOC lower limit or Vmin being less than or equal to a predetermined discharging termination battery cell voltage lower limit, the charging / discharging system determines discharging termination.

[0020] According to the implementation plan, the current state may further include a pause state. The charging / discharging system can determine the start time of the pause sequence based on the intensity of the current flowing in the EV1 battery, and determine the end time of the pause state by comparing the voltage change of all battery cells of the EV1 battery with the voltage reference value corresponding to the previous state after the pause sequence is started. The previous state may include a charging state and a discharging state.

[0021] According to the implementation plan, the charging / discharging system can drive a pause timer when the pause sequence is started, and terminate the pause state based on the expiration of the pause timer.

[0022] According to the implementation scheme, the charging / discharging system may include multiple fast chargers. The charging / discharging system may, based on EV1 and EV2 being connected to different fast chargers among the multiple fast chargers, send an analog signal via power line communication to each of EV1 and EV2 to generate a direct high-voltage path, and based on the analog signal, shut off the high-voltage relay of each of EV1 and EV2, thus generating a direct high-voltage path between the fast charging port and the high-voltage battery.

[0023] According to the implementation scheme, the diagnostic device can calculate the depth of discharge (DOD) of the current charge and discharge (also referred to as "current charge / discharge DOD") based on information about the battery capacity specifications and current SOC obtained through diagnostic communication for at least one corresponding EV1 or EV2, and determine and display at least one user-selectable diagnostic option by checking whether the current charge / discharge DOD is within the available range.

[0024] According to another aspect of the present invention, a method for diagnosing and evaluating the state of an electric vehicle battery includes: generating a direct high-voltage path for simultaneous charging and discharging between a target vehicle (EV1) and a central vehicle (EV2) by a charging / discharging system; obtaining vehicle data corresponding to each charging and discharging operation from EV1 via diagnostic communication by a diagnostic device; and diagnosing and evaluating the state of the EV1 battery based on the vehicle data by the diagnostic device. Energy released from the EV1 battery charges the EV2 battery via the charging / discharging system, and energy released from the EV2 battery charges the EV1 battery via the charging / discharging system.

[0025] According to the implementation plan, the method may further include: determining the start time of the discharge and charge sequence of the EV1 battery based on the current state of charge (SOC) of the EV1 battery by a diagnostic device or a charging / discharging system.

[0026] According to the implementation scheme, the method may further include: receiving information about the current SOC of the EV1 battery from a diagnostic device by the charging / discharging system to determine the start time point of the discharge and charging sequence of the EV1 battery. Specifically, the diagnostic device is configured to obtain information about the current SOC of the EV1 battery from the EV1 via diagnostic communication.

[0027] According to the implementation scheme, the vehicle data corresponding to each charging and discharging may include at least one of the EV1 battery's SOC, maximum voltage (Vmax), or minimum voltage (Vmin).

[0028] According to the implementation plan, the method may further include: the charging / discharging system comparing vehicle data with reference values ​​corresponding to the current state of the battery to determine the time point for termination of charging and discharging. The current state of the vehicle includes the battery's state of charge and state of discharge.

[0029] According to the implementation scheme, the method may further include: when the current state is a charging state, or based on the current state being a charging state, determining charging termination by the charging / discharging system based on the SOC being greater than or equal to a predetermined charging termination SOC upper limit, or Vmax being greater than or equal to a predetermined charging termination battery cell voltage upper limit and Vmin being greater than or equal to a predetermined charging termination battery cell voltage lower limit; and when the current state is a discharging state, or based on the current state being a discharging state, determining discharging termination by the charging / discharging system based on the SOC being less than or equal to a predetermined discharging termination SOC lower limit or Vmin being less than or equal to a predetermined discharging termination battery cell voltage lower limit.

[0030] According to the implementation scheme, the current state may further include a pause state. The method may further include: determining the start time of the pause sequence by the charging / discharging system based on the intensity of the current flowing in the EV1 battery; and determining the end time of the pause state by the charging / discharging system by comparing the voltage change of all cells in the EV1 battery after the pause sequence is started with a voltage reference value corresponding to the previous state. The previous state may include a charging state and a discharging state.

[0031] According to the implementation plan, the method may further include: the charging / discharging system driving a pause timer when initiating a pause sequence, and the charging / discharging system terminating the pause state based on the expiration of the pause timer.

[0032] According to the implementation scheme, the charging / discharging system may include multiple fast chargers. The method may further include: the charging / discharging system, based on EV1 and EV2 being respectively connected to different fast chargers among the multiple fast chargers, transmitting an analog signal via power line communication to each of EV1 and EV2 for generating a direct high-voltage path. High-voltage relays of EV1 and EV2 may be switched off based on the analog signal, and a direct high-voltage path is generated between the fast charging port and the high-voltage battery.

[0033] According to the implementation scheme, the method may further include: the diagnostic device calculating the current depth of discharge (DOD) of the charge / discharge based on battery capacity specification information and current SOC information corresponding to at least one of EV1 or EV2 obtained through diagnostic communication; and the diagnostic device determining and displaying at least one user-selectable diagnostic option by checking whether the current DOD of the charge / discharge is within the available range. Attached Figure Description

[0034] The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings:

[0035] Figure 1This is a schematic diagram illustrating a system for diagnosing and assessing the state of an electric vehicle battery according to an embodiment of the present invention;

[0036] Figure 2 This is a flowchart illustrating a method for diagnosing and evaluating electric vehicle batteries according to an embodiment of the present invention;

[0037] Figure 3 This is a schematic diagram showing the detailed structure of a charging / discharging system according to an embodiment of the present invention;

[0038] Figure 4 This is a schematic diagram illustrating the detailed structure of a system for diagnosing and evaluating electric vehicle batteries according to an embodiment of the present invention;

[0039] Figure 5 This is a flowchart illustrating a method for operating a charging / discharging system according to an embodiment of the present invention;

[0040] Figure 6 This is a flowchart illustrating a method for using an operational diagnostic apparatus according to an embodiment of the present invention;

[0041] Figure 7 This is a schematic diagram illustrating the transmission and reception of information between components in a system for diagnosing and assessing the battery status of an electric vehicle according to an embodiment of the present invention.

[0042] Figure 8 This is a flowchart illustrating a method for diagnosing and assessing the state of an electric vehicle battery according to an embodiment of the present invention;

[0043] Figure 9 This is a flowchart illustrating a method for ending a pause state according to an embodiment of the present invention;

[0044] Figure 10 This is a flowchart illustrating a charging / discharging termination method according to an embodiment of the present invention; and

[0045] Figure 11 This is a block diagram illustrating a computing system according to an embodiment of the present invention.

[0046] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way. Detailed Implementation

[0047] In the following, some embodiments of the invention will be described in detail with reference to the accompanying drawings. When adding reference numerals to the components in each drawing, it should be noted that identical or equivalent components will be indicated by the same reference numerals even if shown in other drawings. Furthermore, in describing embodiments of the invention, detailed descriptions of related known configurations or functions are omitted when it is determined that such detailed descriptions would hinder understanding of the embodiments of the invention.

[0048] When describing components of the present invention, terms such as first, second, A, B, (a), (b), etc., may be used. These terms are provided only to distinguish elements from other elements, and the nature, sequence, order, and number of elements are not limited by these terms. Furthermore, unless otherwise defined, all terms used herein (including technical or scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Unless expressly defined in the specification of this invention, terms defined in general dictionaries should be interpreted as having a meaning consistent with the context of the relevant art, and not as having an ideal or overly formal meaning.

[0049] When the components, controllers, devices, elements, apparatuses, systems, etc. of the present invention are described as having a purpose or performing an operation or function, the components, controllers, devices, elements, apparatuses, systems, etc. herein should be considered as "configured" to satisfy that purpose or perform that operation or function. Each component, controller, device, element, apparatus, system, etc. may be embodied independently or as part of an apparatus and may include a processor and memory (e.g., a non-volatile computer-readable medium).

[0050] In this invention, each of phrases such as “A or B”, “at least one of A and B”, “at least one of A or B”, “A, B or C”, “at least one of A, B and C”, “at least one of A, B or C”, and “at least one of A, B or C or a combination thereof” may include any one or all possible combinations of the items listed together in the corresponding phrase.

[0051] In the following text, refer to Figures 1 to 11 The embodiments of the present invention are described in detail.

[0052] Figure 1 This is a schematic diagram illustrating a system for diagnosing and assessing the state of an electric vehicle battery according to an embodiment of the present invention.

[0053] Reference Figure 1 The system 1 for diagnosing and assessing battery status may schematically include a target vehicle (EV1) 10, a center vehicle (EV2) 20, a charging / discharging system 30, and a diagnostic device 40.

[0054] When EV1 10 (which serves as the target vehicle for battery diagnostics and evaluation) is brought to the center, EV1 10 and EV2 20 can be connected via a charging cable (or fast charger) located in the charging / discharging system 30. The fast charger is a high-power charging device or system that delivers energy at a rate significantly higher than that of a conventional charger, thereby shortening battery charging time by increasing voltage, current, or both, while ensuring safety and efficiency through advanced charging protocols.

[0055] EV1 10 and EV2 20 can send signals for charging / discharging and charging / discharging energy to the charging / discharging system 30 or receive signals for charging / discharging and charging / discharging energy from the charging / discharging system 30 via the connected charging cable.

[0056] The diagnostic device 40 can be connected to the on-board diagnostic (OBD) terminal located in each of EV1 10 and EV2 20 to perform diagnostic communications, and can establish a separate communication channel so that the diagnostic device 40 can send and receive signals with the charging / discharging system 30. For example, the charging / discharging system 30 and the diagnostic device 40 can be connected via wired cables such as Universal Serial Bus (USB) cables, High Definition Multimedia Interface (HDMI) cables, Ethernet cables, etc., but this is only one implementation. The charging / discharging system 30 and the diagnostic device 40 can also be connected wirelessly via communications such as Bluetooth, Wi-Fi, 4G Long-Term Evolution (LTE), 5G New Radio (NR).

[0057] To perform diagnostics and evaluation, the EV1 10's battery needs to be discharged to the specified diagnostic start-up reference state of charge (SOC) level.

[0058] As an example, the energy released from the battery of EV1 10 can be directly transferred to EV2 20 via the charging / discharging system 30 and used to charge the battery of EV2 20. In other words, the charging of the central vehicle battery can be performed simultaneously with the discharging of the target battery.

[0059] The charging / discharging system 30 can generate a specified analog signal, enabling EV1 10 to recognize the charging / discharging system 30 as a high-speed charger. EV1 10 can determine that it is connected to the high-speed charger based on the received analog signal, and can generate a high-voltage path from the fast charging port to the high-voltage battery.

[0060] Furthermore, the charging / discharging system 30 can generate a specified analog signal, enabling the EV2 20 to recognize the charging / discharging system 30 as a high-speed charger. The EV2 20 can determine that it is connected to the high-speed charger based on the received analog signal and can generate a high-voltage path from the fast charging port to the high-voltage battery.

[0061] As an example, when it is confirmed that the diagnostic device 40 is connected to EV1 10 and EV2 20 via diagnostic communication, and that EV1 10 and EV2 20 are connected to the charging / discharging system 30, the diagnostic device 40 can control the charging / discharging system 30 to generate an analog signal for creating a high-voltage path and send the analog signal to EV1 10 and EV2 20. However, this is only an example, and the charging / discharging system 30 can also automatically generate the analog signal based on its power line communication connection with EV1 10 and EV2 20.

[0062] As a result, the charging / discharging system 30 can control the formation of a high-voltage path between two electrically isolated but magnetically connected vehicles using the aforementioned analog signals.

[0063] The charging / discharging system 30 may be equipped with a high-frequency DC / DC power converter to convert energy released from one vehicle and send that energy to another vehicle.

[0064] Most of the energy discharged by one vehicle can be used to charge other vehicles, while only a portion of the discharged energy may be lost due to power conversion within the charging / discharging system 30.

[0065] When the State of Charge (SOC) reaches a specified reference value, EV1 10 can stop discharging and enter a pause state. For example, EV1 10 can send battery status information to the diagnostic device 40, and based on the battery status information, when the SOC of EV1 10 reaches the specified reference value, the diagnostic device 40 can send a specified control signal requesting the cessation of discharge to EV1 10. As another example, the diagnostic device 40 can send information about the SOC reference value for stopping discharge to EV1 10, and when the current SOC reaches the SOC reference value, EV1 10 can stop discharging and enter a pause state. The operation in the pause state will become clearer with the following description of the accompanying drawings.

[0066] After the pause state ends, EV1 10 can switch to charging state and receive energy released by EV2 20 through charging / discharging system 30 to charge its own battery.

[0067] The diagnostic device 40 can collect discharge and charge data from EV1 10 and perform diagnostics and evaluations on the battery of EV1 10 based on the collected discharge and charge data. For example, discharge and charge data can be collected after discharge and charge have ended, but this is only one implementation, and discharge and charge data can also be collected at specified intervals.

[0068] As described above, the system 1 for diagnosing and assessing the state of an electric vehicle battery according to the present invention can significantly shorten the time required to charge / discharge the target vehicle by simultaneously performing electric vehicle-to-electric vehicle (EV-to-EV) fast charging / discharging through the charging / discharging system 30, and can also provide the function of diagnosing and assessing the state of a high-voltage battery by minimizing energy waste by recovering the released energy as charging energy.

[0069] Figure 2 This is a flowchart illustrating a method for diagnosing and evaluating electric vehicle batteries according to an embodiment of the present invention.

[0070] Reference Figure 2 In S210, the system 1 for diagnosing and evaluating the electric vehicle battery can compare the SOC of EV1 10 with a first reference SOC to determine whether the battery of EV1 10 is discharged.

[0071] As a comparison, when the SOC of EV1 exceeds the first reference SOC, in S220, the system 1 for diagnosing and evaluating the electric vehicle battery can control EV1 10 and EV2 20 to identify the charging / discharging system 30 as a high-speed charger. For example, the charging / discharging system 30 can control EV1 10 and EV2 20 to identify the charging / discharging system 30 as a high-speed charger by sending a specified analog signal to EV1 10 and EV2 20, and each of EV1 10 and EV2 20 can generate a high-voltage path between its own fast charging port and the high-voltage battery according to the detected analog signal. In this case, a magnetically connected high-voltage path can be formed between EV1 10 and EV2 20.

[0072] In S230, the system 1 for diagnosing and evaluating the electric vehicle battery can control the energy released from the battery of EV1 10 to be charged into the battery of EV220 through the charging / discharging system 30 based on the high-voltage path of the magnetic connection generated between EV1 10 and EV2 20.

[0073] In S240 and S250, based on the SOC of EV1 10 reaching a first reference SOC, system 1 for diagnosing and evaluating the electric vehicle battery can collect discharge data by stopping the battery discharge of EV1 10 and entering a pause state. For example, diagnostic device 40 can obtain discharge data from EV1 10 via diagnostic communication.

[0074] In S260, the system 1 for diagnosing and evaluating electric vehicle batteries can control the energy released from the battery of EV2 20 to be charged into the battery of EV1 10 through the charging / discharging system 30.

[0075] In S270, the system 1 with diagnostic device 40 can compare the SOC of EV1 10 with a second reference SOC, which can be defined and set to be greater than the first reference SOC. For example, diagnostic device 40 can obtain charging data from EV1 10 via diagnostic communication, and the system 1 can determine that the SOC of EV1 10 exceeds the second reference SOC.

[0076] After determining in S270 that the SOC of EV1 10 exceeds the second reference SOC, in S280, based on the fact that the SOC of EV1 10 exceeds the second reference SOC, the system 1 used to diagnose and evaluate the electric vehicle battery can collect charging data by stopping the charging of the battery of EV1 10 and putting it into a pause state.

[0077] In S290, the system 1 for diagnosing and evaluating the electric vehicle battery can diagnose and evaluate the battery state of EV1 10 based on discharge and charge data. For example, the diagnosis and evaluation of the battery state of EV1 10 can be performed by the diagnostic device 40, and the results of the diagnosis and evaluation can be output through a display (not shown) provided in the diagnostic device 40. Furthermore, the results of the diagnosis and evaluation can be sent to a cloud server (not shown) connected to a communication network (not shown).

[0078] In S210 and S295, when the SOC of EV1 10 is less than the first reference SOC, the system 1 for diagnosing and evaluating the electric vehicle battery can charge the battery of EV1 10 until the SOC of EV1 10 exceeds the first reference SOC. For example, the charging / discharging system 30 can convert the energy released from the battery of EV2 20 into charging the battery of EV1 10 according to the control signal of the diagnostic device 40.

[0079] Figure 3 This is a schematic diagram showing the detailed structure of a charging / discharging system according to an embodiment of the present invention.

[0080] Reference Figure 3The charging / discharging system 30 may include a first communication device 31 to a third communication device 33, a central controller 34, a human machine interface (HMI) 35, and a power conversion device 36.

[0081] The first communication device 31 can communicate with EV1 10, the second communication device 32 can communicate with EV2 20, and the third communication device 33 can communicate with the diagnostic device 40.

[0082] Each of the first communication device 31 and the second communication device 32 of the charging / discharging system 30 may be equipped with a Supply Equipment Communication Controller (SECC), i.e., a communication controller for the power supply equipment, and each of EV1 10 and EV2 20 may be equipped with an Electric Vehicle Communication Controller (EVCC), i.e., a communication controller for the electric vehicle, enabling the charging / discharging system 30 to perform mutual communication with each of EV1 10 and EV2 20. For example, the SECC and EVCC may establish a charging session and exchange information with each other according to the protocols specified in German technical standard DIN 70121 or International Organization for Standardization ISO 15118-2&20. As an example, the charging / discharging system 30 may control (or cause) EV1 10 and EV2 20 to shut off the high-voltage relays by using specified control signals according to the protocols specified in DIN 70121 or ISO 15118-2&20. The inverters and converters of the EVs are connected to the high-voltage batteries via relays. In other words, when the EV is driving the motor or charging the high-voltage battery, the EV can control the high-voltage relay to connect the high-voltage battery to the motor (load) or the on-board charger (OBC).

[0083] The third communication device 33 may be equipped with a vehicle diagnostic communication connector, such as an On-Board Diagnostic II (OBD-II) terminal, and connected to the diagnostic device 40. However, this is only one implementation, and it can also communicate with the diagnostic device 40 via Bluetooth, Wi-Fi, or mobile communication. For example, the Unified Diagnostic Service (UDS) defined in ISO 14291-1 can be applied to diagnostic communication, but this is only one implementation, and other diagnostic communication schemes can be applied according to the implementation methods of those skilled in the art.

[0084] The diagnostic device 40 can be connected via a diagnostic communication connector (e.g., an OBD-II terminal located in each of EV1 10 and EV2 20) to exchange signals and information with the corresponding electronic control unit (ECU) of the respective EV. In this case, the ECU may include an ECU such as a battery management system (BMS) that manages the state of the high-voltage battery.

[0085] The central controller 34 can control the overall input / output and sub-modules of the charging / discharging system 30. In this case, the sub-modules may include the first communication device 31 to the third communication device 33, the HMI 35, and the power conversion device 36.

[0086] HMI 35 can provide a user interface for input and output. For example, HMI 35 may include various input / output devices such as a keyboard, scroll wheel, display, buttons, switches, etc. Central controller 34 can output at least one piece of information about the charging / discharging status and target setting information for charging / discharging via the display. In addition, central controller 34 can collect battery status information of EV1 10 and EV2 20 from diagnostic device 40 and display it on the display.

[0087] The power conversion device 36 can perform charging / discharging power conversion between EV1 10 and EV2 20 according to the control signals of the central controller 34. As an example, the central controller 34 can set the charging and / or discharging power conversion ratio of the power conversion device 36 based on the discharge and / or charging target values ​​input through the diagnostic device 40. For example, the target values ​​may include SOC, battery pack voltage, battery cell voltage, etc., but the implementation is not limited to these. In this case, the target values ​​can be determined by considering the currently available charging / discharging capacity of each vehicle.

[0088] Figure 4 This is a schematic diagram illustrating the detailed structure of a system for diagnosing and evaluating electric vehicle batteries according to an embodiment of the present invention.

[0089] Reference Figure 4 The system 1 used for diagnosing and evaluating electric vehicle batteries can generally include EV1 10, EV2 20, charging / discharging system 30, diagnostic device 40, and cloud server 50. In this case, the diagnostic device 40 and cloud server 50 can be connected via wired and / or wireless communication networks.

[0090] EV1 10 may include an OBD connector 11, a high-voltage battery 12, a fast charging port 13, and a power line communication device 14, and EV2 20 may include an OBD connector 21, a high-voltage battery 22, a fast charging port 23, and a power line communication device 24.

[0091] The diagnostic device 40 may include at least one of a first diagnostic port 41 to a third diagnostic port 43, a display 44, an input device 45, a communication device 46, and a processor 47.

[0092] The first diagnostic port 41 can be connected to the OBD connector 11 of EV1 10, the second diagnostic port 42 can be connected to the OBD connector 21 of EV2 20, and the third diagnostic port 43 can be connected to the third communication device 33 of the charging / discharging system 30.

[0093] The power line communication device 14 of EV1 10 can be connected to the first communication device 31 of the charging / discharging system 30, and the power line communication device 24 of EV2 20 can be connected to the second communication device 32 of the charging / discharging system 30.

[0094] The charging / discharging system 30 can control each EV to shut off its high-voltage relay and create a high-voltage path between the high-voltage battery 12 or 22 and the fast charging port 13 or 23 by sending specified analog signals to EV1 10 and EV2 20 via the first communication device 31 and the second communication device 32. Therefore, a path for direct high-voltage charging / discharging can be formed between the high-voltage battery 12 of EV1 10 and the high-voltage battery 22 of EV2 20.

[0095] Figure 5 This is a flowchart illustrating a method for operating a charging / discharging system according to an embodiment of the present invention.

[0096] Reference Figure 4 and Figure 5 When the charging / discharging system 30 confirms that the fast charging connector is properly connected to EV1 10 and EV2 20, in S510, the charging / discharging system 30 can send a first control signal to each of EV1 10 and EV2 20 so that EV1 10 and EV2 20 can recognize that EV1 10 and EV2 20 are connected to different fast chargers.

[0097] In S520, the charging / discharging system 30 can control EV1 10 and EV2 20 to shut off their respective high-voltage relays by sending a second control signal to each of EV1 10 and EV2 20.

[0098] In S530, the charging / discharging system 30 can control the generation of a direct high-voltage path between the fast charging ports 13 and 23 of each EV (i.e., EV1 and EV2) and the high-voltage batteries 12 and 22 by sending a third control signal to each of EV1 10 and EV2 20.

[0099] In S540, the charging / discharging system 30 can receive information from the diagnostic device 40 regarding the selection of diagnostic options and target values. In this case, the target value may include at least one of the battery's SOC, battery pack voltage, or battery cell voltage.

[0100] In S550, the charging / discharging system 30 can control the charging / discharging between EV1 10 and EV2 20 by performing power conversion based on information about diagnostic option selection and target values.

[0101] Figure 6 This is a flowchart illustrating a method for using an operational diagnostic apparatus according to an embodiment of the present invention.

[0102] Reference Figure 4 and Figure 6 In S610, the diagnostic device 40 can obtain capacity information and current SOC status information of the Battery System Assembly (BSA) in each corresponding specification of EV1 10 and EV2 20 through diagnostic communication with EV1 10 and EV2 20. In this context, BSA refers to the finished product that integrates the battery pack with electronic components and the Battery Management System (BMS) to ensure the safe and efficient operation of the battery in the electric vehicle. A high-capacity / high-efficiency battery system is a key component determining the quality and performance of the electric vehicle.

[0103] In S620, the diagnostic device 40 can calculate and output the current charge / discharge available capacity for each of EV1 10 and EV2 20 based on the BSA capacity information and the current SOC status information in the specification. For example, the current charge / discharge available capacity can be calculated as the current depth of discharge (DOD).

[0104] In S630, the diagnostic device 40 can receive discharge and charge target information from the user via a set input device. In this case, the target information may include SOC, battery pack voltage, battery cell voltage, etc., but the implementation is not limited to this.

[0105] In S640, the diagnostic device 40 can calculate the available depth of discharge (DOD) based on discharge and charge target information. In this case, DOD is the opposite of SOC and is an indicator of the battery's state of discharge. In other words, for electric vehicles, DOD indicates the percentage of the battery that has been discharged from a fully charged state (i.e., SOC: 100%).

[0106] In S650, the diagnostic device 40 can check whether the amount of charge / discharge required for battery status assessment is within the available range, based on the current available charge / discharge capacity and / or available charge / discharge DOD.

[0107] In S660, the diagnostic device 40 can determine the currently selectable diagnostic options based on the inspection results of S650 and display them on the display screen. For example, when the discharge DOD is less than the available discharge DOD, the diagnostic device 40 can determine that a discharge diagnostic mode is executable. When the charging DOD is less than the available charging DOD, the diagnostic device 40 can determine that one of the following is executable: a receiving SOC recovery mode, a shipping SOC setting mode, or a charging diagnostic execution mode.

[0108] In S670, the diagnostic device 40 can send information about the diagnostic options selected by the user and target information to the charging / discharging system 30. In this case, the target information may include the target SOC.

[0109] In S680, the diagnostic device 40 can obtain vehicle data for charging / discharging evaluation through diagnostic communication with EV1 10 and EV2 20.

[0110] In S690, the diagnostic device 40 can diagnose the SOH and abnormal conditions of the EV1 10 battery based on vehicle data.

[0111] In S695, after outputting the diagnostic results to the display screen, the diagnostic device 40 can output the diagnostic results of the EV1 10 battery to the cloud server 50.

[0112] Figure 7 This is a schematic diagram illustrating the transmission and reception of information between components in a system for diagnosing and assessing the state of an electric vehicle battery according to an embodiment of the present invention.

[0113] Reference Figure 7The diagnostic device 40 can obtain battery specification and status information from EV1 10 and EV2 20 through diagnostic communication, which includes at least one of the following in the specification: power per unit time (Capacity [kWh]), battery cell voltage (V.cell [mV]), battery pack voltage (V.pack [V]), battery temperature (T.cell [C]), state of charge (SOC [%)), battery pack current (Ipack [A]), and charge per unit time (Iaccumul. [Ah]).

[0114] The diagnostic device 40 can receive current status information from the charging / discharging system 30. In this case, the current status information may include at least one of the following: a first status information (Ready), a second status information (Fault), a third status information (Pre-chg), and a fourth status information. The first status information (Ready) indicates whether charging / discharging preparation is complete; the second status information (Fault) indicates whether an error condition exists; the third status information (Pre-chg) is related to pre-charging; and the fourth status information indicates whether the connected electric vehicle is in charging mode (Chg) or discharging mode (Dchg).

[0115] The diagnostic device 40 can send reference parameters to the charging / discharging system 30 for determining the end of the pause state and the end of charging / discharging. For example, the reference parameter values ​​for determining the end of the pause state may include a reference value for the voltage drop of all battery cells (ΔV.relax.down) and the pause timer (T.relax) value, and the reference parameter values ​​for determining the end of charging / discharging may include the upper limit of SOC at the end of charging (ChgStop.SOC.max) and the lower limit of SOC at the end of discharging (DchgStop.SOC.min), the upper limit of battery cell voltage at the end of charging (ChgStop.Vcell.max), the lower limit of battery cell voltage at the end of charging (ChgStop.Vcell.min), and the lower limit of battery cell voltage at the end of discharging (DchgStop.Vcell.min).

[0116] The charging / discharging system 30 can send and receive data with each EV according to the fast charging protocol.

[0117] Figure 8 This is a flowchart illustrating a method for diagnosing and assessing the state of an electric vehicle battery according to an embodiment of the present invention.

[0118] Reference Figure 4 and Figure 8After connecting the diagnostic device 40 to the OBD connectors 11 and 21 of EV1 10 (which serves as the target vehicle for diagnosis) and EV2 20 (which serves as the center vehicle), in S801 and S802, the fast charging connector provided in the charging / discharging system 30 can be connected to the fast charging ports 13 and 23 of EV1 10 and EV2 20.

[0119] In S803, the charging / discharging system 30 can establish a first communication channel for controlling the charging / discharging of EV1 10 and EV2 20.

[0120] In S804, the diagnostic device 40 can establish a second communication channel for diagnostic communication with EV1 10 and EV2 20. Furthermore, in S805, the diagnostic device 40 can establish a third communication channel for sending and receiving information with the charging / discharging system 30.

[0121] In S806 and S807, when the user's intention to perform a diagnosis is expressed through the diagnostic device 40, the charging / discharging system 30 can initiate communication with the EVCCs 14 and 24 of EV1 10 and EV220 by driving SECCs 31 and 32.

[0122] In S808 and S809, based on the SOC of EV1 10 (as the target vehicle for diagnosis) being greater than a first reference value, the diagnostic device 40 can control the charging / discharging system 30 to initiate a discharge sequence of the EV1 10's battery. For example, the first reference value can be set to 20%, but this is only one implementation, and the first reference value can also be set to different values ​​according to the design of those skilled in the art.

[0123] In S810 to S812, after the discharge sequence begins, the diagnostic device 40 can enter a pause state and check the battery capacity specifications and current SOC of EV1 10 and EV2 20, and then calculate the available charge DOD and available discharge DOD.

[0124] In S813 to S815, based on the fact that the DOD of discharge is less than the DOD of available discharge and the DOD of charging is less than the DOD of available charging, the diagnostic device 40 can display at least one diagnostic option and can request the user to select one of the displayed diagnostic options.

[0125] In S816, the diagnostic device 40 can discharge the battery of EV1 10 by controlling the charging / discharging system 30 according to the diagnostic options selected by the user. In this case, discharge can be performed using either a standard charging connector (CC) or a fast charging connector (QCC).

[0126] In S817 to S819, after the discharge is terminated, the diagnostic device 40 can enter a pause state after initiating the SOH assessment and abnormal state diagnosis sequence for the battery of EV1 10.

[0127] In S820, the diagnostic device 40 can initiate charging of the EV1 10's battery after the pause state ends. In this case, charging can be performed using either the standard charging connector (CC) or the fast charging connector (QCC).

[0128] In S821 to S823, if the SOC of the battery based on EV1 10 is greater than the specified second reference value, the diagnostic device 40 can enter a pause state after charging is terminated.

[0129] In S824, the diagnostic device 40 can diagnose the abnormal state of the battery of EV1 10 based on the current change in the battery of EV1 10 and perform SOH diagnosis.

[0130] In S825, the diagnostic device 40 can output the diagnostic and evaluation results of the battery status of EV1 10 through the equipped display.

[0131] Figure 9 This is a flowchart illustrating a method for ending a pause state according to an embodiment of the present invention.

[0132] As an example, the process of determining whether to end the pause state can be performed by the diagnostic device 40, but this is only one implementation. According to another implementation, the process of determining whether to end the pause state can also be performed by the charging / discharging system 30. The following description focuses on an example of the diagnostic device 40 determining whether the pause state is interrupted.

[0133] Reference Figure 9 In S901, the diagnostic device 40 can compare the current current value flowing in the target vehicle's battery with a specified reference current value to determine the time point for entering the pause state, i.e., the time point for starting the pause state. For example, the reference current value can be set to 0.5A, and the pause state can be entered when the current value is less than 0.5A.

[0134] In S902 and S903, after entering the pause state, the diagnostic device 40 can obtain the initial full battery cell voltage values ​​(V.cell.xxx.init) from the target vehicle and store them in its internal memory, then start counting the pause timer (T.relax). For example, the pause timer can be set to 60 minutes, but this is only one implementation, and as those skilled in the art can design, the pause timer can also be set to a longer or shorter time.

[0135] The diagnostic device 40 can obtain the current voltage values ​​of all battery cells (V.cell.xxx.cur) from the target vehicle at regular intervals and store them in its internal memory.

[0136] In S905, the diagnostic device 40 can check whether the previous state was a charging state or a discharging state.

[0137] In S906, based on the previous state being a charging state, the diagnostic device 40 can enter a charging-after-pause-termination decision mode. Conversely, when the previous state was a discharging state, the diagnostic device 40 can enter a discharging-after-pause-termination decision mode.

[0138] When entering the discharge-pause termination decision mode, in S907, the diagnostic device 40 can calculate the total decrease in battery cell voltage (ΔV.relax.down). In this case, the total decrease in battery cell voltage can be calculated by subtracting V.cell.xxx.cur from V.cell.xxx.init.

[0139] In S908 and S909, when the pause timer has not expired, the diagnostic device 40 can compare ΔV.relax.down with a first voltage reference value to determine whether to end the pause. For example, the first voltage reference value can be set to 5mV. In this case, when ΔV.relax.down is less than 5mV, the diagnostic device 40 can terminate the pause state.

[0140] When entering the charging pause termination decision mode, in S911, the diagnostic device 40 can calculate the total increase in battery cell voltage change (ΔV.relax.up). In this case, the total increase in battery cell voltage change can be calculated by subtracting V.cell.xxx.cur from V.cell.xxx.init.

[0141] In S912 and S913, when the pause timer has not expired, the diagnostic device 40 can compare ΔV.relax.up with a second voltage reference value to determine whether to end the pause. For example, the second voltage reference value can be set to 10mV. In this case, when ΔV.relax.up is less than 10mV, the diagnostic device 40 can terminate the pause state.

[0142] When the pause timer expires or the current is greater than or equal to the reference current value, the diagnostic device 40 can immediately end the pause state.

[0143] As an example, taking into account the error of the voltage sensor, the first voltage reference value and the second voltage reference value can be determined to be sufficiently small values ​​among the voltage changes during discharge and charging.

[0144] Figure 10 This is a flowchart illustrating a charging / discharging termination method according to an embodiment of the present invention.

[0145] As an example, the process of determining whether charging / discharging is complete can be performed by the diagnostic device 40, but this is only one implementation. According to another implementation, the process of determining whether charging / discharging is complete can also be performed jointly by the charging / discharging system 30 and the diagnostic device 40. The following description focuses on an example where the charging / discharging system 30 and the diagnostic device 40 jointly determine whether to stop charging / discharging.

[0146] In S1001 and S1002, the diagnostic device 40 can obtain diagnostic target vehicle data through diagnostic communication with the target vehicle. In this case, the diagnostic target vehicle data may include data regarding the SOC, maximum voltage (Vmax), and minimum voltage (Vmin) of the target vehicle's battery, but the implementation is not limited to this. The minimum voltage Vmin may refer to the minimum value among each measured voltage of the battery cell. The maximum voltage Vmax may refer to the maximum value among each measured voltage of the battery cell.

[0147] In S1003 and S1004, the diagnostic device 40 can send the obtained diagnostic target vehicle data to the charging / discharging system 30 through a communication channel connected to the charging / discharging system 30.

[0148] In S1005, the charging / discharging system 30 can check whether the current state is charging or discharging.

[0149] As a result of the check, when the current state is charging, in S1006, the charging / discharging system 30 can compare each of SOC, Vmax, and Vmin with a predefined reference value to determine whether to terminate charging. For example, when SOC is greater than or equal to the upper limit of charging termination SOC, or when Vmax is greater than or equal to the upper limit of charging termination battery cell voltage and Vmin is greater than or equal to the lower limit of charging termination battery cell voltage, the charging / discharging system 30 can determine that charging has terminated. The reference values ​​related to determining the termination of the charging state can be applied as an AND logic between the upper limit of SOC used to determine whether SOC meets the capacity assessment upper limit and the upper and lower limits of the battery cell voltage used for diagnostic data.

[0150] As a result of the check in S1005, when the current state is a discharge state, in S1007, the charge / discharge system 30 can compare each of SOC and Vmin with a predefined reference value to determine whether to terminate the discharge. For example, when SOC is less than or equal to the discharge termination SOC lower limit or Vmin is less than or equal to the discharge termination battery cell voltage lower limit, the charge / discharge system 30 can determine that the discharge has terminated. The SOC lower limit or battery cell voltage lower limit, as reference values ​​related to determining the termination of the discharge state, can be applied to capacity assessment or anomaly diagnostic assessment.

[0151] Figure 11 This is a block diagram illustrating a computing system according to an embodiment of the present invention.

[0152] Reference Figure 11 The computing system 1000 may include at least one processor 1100, a memory 1300, a user interface input device 1400, a user interface output device 1500, a storage device 1600, and a network interface 1700 connected via a bus 1200.

[0153] Processor 1100 may be a central processing unit (CPU) or semiconductor device that processes instructions stored in memory 1300 and / or storage device 1600. Memory 1300 and storage device 1600 may include various types of volatile or non-volatile storage media. For example, memory 1300 may include read-only memory (ROM) and random access memory (RAM).

[0154] Accordingly, the processes of the methods or algorithms related to embodiments of the present invention can be directly implemented by hardware, software modules, or a combination of both, executed by processor 1100. Software modules can reside in storage media (i.e., memory 1300 and storage device 1600), such as RAM, flash memory, ROM, erasable programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), registers, hard disks, solid-state drives (SSDs), removable disks, or optical disc (CD)-ROMs.

[0155] The storage medium is coupled to the processor 1100, and the processor 1100 can read information from and write information to the storage medium. Alternatively, the storage medium can be integrated with the processor 1100. The processor and storage medium can reside in an Application Specific Integrated Circuit (ASIC). The ASIC can reside in the user terminal. Alternatively, the processor and storage medium can exist as independent components in the user terminal.

[0156] As an example, computing system 1000 can be implemented to perform the above... Figures 1 to 10 At least one function and method disclosed herein, and applied to at least one of the above-described EV1 10 and EV2 20 and charging / discharging system 30.

[0157] This technology provides an apparatus, a system including the apparatus, and a method thereof for diagnosing and evaluating the state of charge and discharge of electric vehicle batteries.

[0158] Furthermore, this technology provides an apparatus for diagnosing and assessing the state of electric vehicle batteries, a system including the apparatus, and a method thereof, which enables faster diagnosis and assessment of EV battery state via electric vehicle-to-electric vehicle (EV-to-EV) power transmission systems.

[0159] Furthermore, this technology provides a charging and discharging method and system that enables rapid and accurate diagnosis and assessment of the high-voltage battery status of a target vehicle by simultaneously performing EV-to-EV charging and discharging, without the need for separate dedicated chargers and dischargers.

[0160] Furthermore, this technology provides a method and system for diagnosing and evaluating battery status through EV-to-EV charging / discharging. This method not only improves discharge power and shortens the time required for discharge, but also minimizes energy waste by recharging the battery with the recovered energy after the released energy is recovered.

[0161] Furthermore, this technology can diagnose the state of high-voltage batteries through EV-to-EV charging / discharging, thus reducing form factor and avoiding additional installation costs and space constraints.

[0162] In addition, this technology can be used to evaluate the charging / discharging of high-voltage batteries in ordinary EVs that are not equipped with multi-inverters.

[0163] Furthermore, various effects can be provided directly or indirectly through this invention.

[0164] Although embodiments of the invention have been described for illustrative purposes, those skilled in the art will understand that various modifications, additions, and substitutions can be made without departing from the scope and spirit of the invention.

[0165] Therefore, the embodiments disclosed in this invention are provided for illustrative purposes and do not limit the technical concept of the invention. It should be understood that such embodiments are not intended to limit the scope of the technical concept of the invention. The scope of protection of this invention should be understood through the appended claims, and all technical concepts within the equivalent scope should be interpreted as being within the scope of the claims of this invention.

Claims

1. A system for diagnosing and assessing battery status, the system comprising: A charging and discharging system configured to establish a direct high-voltage path for charging and discharging between the target vehicle and the central vehicle. as well as The diagnostic device is configured as follows: Obtain vehicle data corresponding to each charging and discharging cycle from the target vehicle via diagnostic communication; Diagnose and assess the battery status of the target vehicle based on vehicle data; Specifically, after the energy released from the target vehicle battery is used to charge the central vehicle battery through the charging and discharging system, the energy released from the central vehicle battery is used to charge the target vehicle battery through the charging and discharging system.

2. The system for diagnosing and evaluating battery status according to claim 1, wherein, The diagnostic device or the charging and discharging system is further configured to: determine the start time of the discharge and charging sequence of the target vehicle battery based on the current state of charge of the target vehicle battery.

3. The system for diagnosing and evaluating battery status according to claim 2, wherein, The charging and discharging system is configured to receive information from the diagnostic device about the current state of charge of the target vehicle battery in order to determine the start time of the discharge and charging sequence of the target vehicle battery. The diagnostic device is configured to obtain information about the current charge status of the target vehicle's battery from the target vehicle via diagnostic communication.

4. The system for diagnosing and evaluating battery status according to claim 1, wherein, The vehicle data corresponding to each charging and discharging includes: diagnosing the state of charge of the target vehicle's battery, at least one of the maximum or minimum voltage.

5. The system for diagnosing and evaluating battery status according to claim 4, wherein, The charging and discharging system is configured to: compare vehicle data with a reference value corresponding to the current state based on the current state in order to determine the time point at which charging and discharging will terminate; The current state includes charging state and discharging state.

6. The system for diagnosing and evaluating battery status according to claim 5, wherein, The charging and discharging system is configured as follows: Based on the current state being a charging state, and based on the power state being greater than or equal to the predetermined upper limit of the power state for charging termination, or the maximum voltage being greater than or equal to the predetermined upper limit of the battery cell voltage for charging termination and the minimum voltage being greater than or equal to the predetermined lower limit of the battery cell voltage for charging termination, charging is terminated. Based on the fact that the current state is a discharge state, and based on the fact that the charge state is less than or equal to the predetermined discharge termination charge state lower limit or the minimum voltage is less than or equal to the predetermined discharge termination battery cell voltage lower limit, the discharge is terminated.

7. The system for diagnosing and evaluating battery status according to claim 6, wherein, The current state further includes a paused state; The charging and discharging system is further configured as follows: The start time of the pause sequence is determined based on the intensity of the current flowing in the battery of the target vehicle. The end time of the pause state is determined by comparing the voltage change of all battery cells in the target vehicle's battery after the pause sequence is started with a voltage reference value corresponding to the previous state. The previous states include the charging state and the discharging state.

8. The system for diagnosing and evaluating battery status according to claim 7, wherein, The charging and discharging system is further configured as follows: When the pause sequence is started, the pause timer is activated; The pause state is terminated when the pause timer expires.

9. The system for diagnosing and evaluating battery status according to claim 1, wherein, The charging and discharging system includes multiple fast chargers; The charging and discharging system is further configured as follows: Based on the fact that the target vehicle and the central vehicle are respectively connected to different fast chargers among multiple fast chargers, analog signals for generating a direct high-voltage path are sent to each of the target vehicle and the central vehicle via power line communication. Based on the analog signal, the high-voltage relays of each of the target vehicle and the central vehicle are shut down for diagnosis. A direct high-voltage path is created between the fast charging port and the high-voltage battery.

10. The system for diagnosing and evaluating battery status according to claim 1, wherein, The diagnostic device is further configured as follows: Based on information about battery capacity specifications and current state of charge obtained through diagnostic communication that corresponds to at least one of the target vehicle or central vehicle being diagnosed, the depth of discharge for the current charge and discharge is calculated. By checking whether the current depth of discharge during charging and discharging is within the usable range, at least one diagnostic option that the user can select is identified and displayed.

11. A method for diagnosing and assessing battery state, the method comprising: The charging and discharging system generates a direct high-voltage path for charging and discharging between the target vehicle and the central vehicle. The diagnostic device obtains vehicle data corresponding to each charging and discharging cycle from the target vehicle via diagnostic communication. The diagnostic device diagnoses and assesses the battery status of the target vehicle based on vehicle data. Specifically, after the energy released from the target vehicle battery is used to charge the central vehicle battery through the charging and discharging system, the energy released from the central vehicle battery is used to charge the target vehicle battery through the charging and discharging system.

12. The method for diagnosing and assessing battery status according to claim 11, further comprising: The diagnostic device or charging and discharging system determines the start time of the discharge and charging sequence of the target vehicle's battery based on the current state of charge of the battery.

13. The method for diagnosing and assessing battery status according to claim 12, further comprising: The charging and discharging system receives information from the diagnostic device about the current state of charge of the target vehicle's battery in order to determine the start point of the discharge and charging sequence for the target vehicle's battery. The diagnostic device is configured to obtain information about the current charge status of the target vehicle's battery from the target vehicle via diagnostic communication.

14. The method for diagnosing and assessing battery status according to claim 11, wherein, The vehicle data corresponding to each charging and discharging includes: diagnosing the state of charge of the target vehicle's battery, at least one of the maximum or minimum voltage.

15. The method for diagnosing and assessing battery status according to claim 14, further comprising: The charging and discharging system compares vehicle data with reference values ​​corresponding to the current state of the battery to determine the point at which charging and discharging will cease. The current state includes both charging and discharging states.

16. The method for diagnosing and assessing battery status according to claim 15, further comprising: Based on the current state being a charging state, and based on the state of charge being greater than or equal to the predetermined upper limit of the state of charge termination, or the maximum voltage being greater than or equal to the predetermined upper limit of the battery cell voltage for charge termination and the minimum voltage being greater than or equal to the predetermined lower limit of the battery cell voltage for charge termination, the charging and discharging system determines the termination of charging. Based on the current state being a discharge state, and based on the state of charge being less than or equal to the predetermined discharge termination state lower limit, or the minimum voltage being less than or equal to the predetermined discharge termination battery cell voltage lower limit, the discharge termination is determined by the charging and discharging system.

17. The method for diagnosing and assessing battery status according to claim 16, wherein, The current state further includes a paused state; The method further includes: The charging and discharging system determines the start time of the pause sequence based on the intensity of the current flowing in the battery of the target vehicle. The charging and discharging system determines the end time of the pause state by comparing the voltage changes of all battery cells in the target vehicle's battery after the pause sequence is initiated with voltage reference values ​​corresponding to the previous state. The previous states include the charging state and the discharging state.

18. The method for diagnosing and assessing battery status according to claim 17, further comprising: The charging and discharging system drives the pause timer when the pause sequence is initiated; The charging and discharging system terminates the pause state based on the expiration of the pause timer.

19. The method for diagnosing and assessing battery status according to claim 11, wherein, The charging and discharging system includes multiple fast chargers; The method further includes: the charging and discharging system, based on the different fast chargers among multiple fast chargers to which the target vehicle and the center vehicle are respectively connected, sending an analog signal for generating a direct high-voltage path to each of the target vehicle and the center vehicle via power line communication. The analog signal is used to shut down the high-voltage relays of the target vehicle and the central vehicle, and a direct high-voltage path is generated between the fast charging port and the high-voltage battery.

20. The method for diagnosing and assessing battery status according to claim 11, further comprising: The diagnostic device calculates the depth of discharge for the current charging and discharging based on information about battery capacity specifications and current state of charge obtained through diagnostic communication that corresponds to at least one of the target vehicle or central vehicle being diagnosed. The diagnostic device determines and displays at least one diagnostic option that the user can select by checking whether the current depth of discharge during charging and discharging is within the usable range.

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