Storage battery online capacity checking method based on multi-diode series unidirectional isolation and related equipment

Abstract

The invention relates to the technical field of power systems, in particular to a storage battery online capacity checking method based on multi-diode series unidirectional isolation and related equipment. The method comprises the following steps: in a capacity checking mode, controlling a storage battery to discharge to a direct current bus at a preset current, and monitoring the voltage of the direct current bus; if the direct current bus voltage is greater than a voltage upper limit threshold value, converting the direct current of the direct current bus into alternating current, and feeding back the alternating current to an alternating current power grid; if the direct-current bus voltage is smaller than or equal to the voltage upper limit threshold value and larger than or equal to the voltage lower limit threshold value, supplying power to the direct-current bus through the storage battery; and if the direct current bus voltage is smaller than the voltage lower limit threshold value, controlling to take electricity from the alternating current power grid, and increasing the voltage of the direct current bus. The storage battery nuclear capacity is discharged to the direct current bus, the electric energy released by the nuclear capacity is distributed, and the electric energy wasted by the nuclear capacity is reduced.

Description

Technical Field

[0001] This application relates to the field of power system technology, and in particular to a method and related equipment for online capacity assessment of batteries based on multi-diode series unidirectional isolation. Background Technology

[0002] The substation uses a DC power supply system as the core power supply architecture for its secondary system. In the event of an AC grid failure, the secondary system is powered by the batteries in the DC power supply system. According to power production regulations, the batteries in the DC power supply system need to undergo periodic capacity verification. Capacity verification involves standardized discharge tests to accurately measure the actual usable capacity of the battery bank, verifying whether it still meets design requirements and operational needs.

[0003] Currently, existing online battery capacity assessment methods involve connecting the battery to a dummy load device to discharge it, completing the capacity assessment during the discharge process. However, this dummy load device results in energy waste from the battery during the capacity assessment process. Summary of the Invention

[0004] The main objective of this application is to propose an online capacity-matching method and related equipment for batteries based on multi-diode series unidirectional isolation, which aims to recover and reuse the electrical energy released during the capacity-matching process and reduce waste.

[0005] To achieve the above objectives, one aspect of this application proposes an online capacity assessment method for batteries based on multi-diode series unidirectional isolation, which is applied to the capacity assessment of batteries in a DC power system, wherein the DC power system includes a DC bus and batteries connected to the DC bus; The method includes: In core capacity mode, the battery is controlled to discharge to the DC bus at a preset current, and the DC bus voltage is monitored; If the DC bus voltage is greater than the upper voltage threshold, the DC power of the DC bus will be converted into AC power and fed back to the AC power grid; If the DC bus voltage is less than or equal to the upper voltage threshold and greater than or equal to the lower voltage threshold, the DC bus is powered through the battery. If the DC bus voltage is lower than the lower voltage threshold, power is drawn from the AC grid to increase the DC bus voltage.

[0006] In some embodiments, the method further includes: When the battery is out of capacity mode, the battery is charged via the charging control module.

[0007] In some embodiments, charging the battery via the charging control module specifically includes: Monitor the voltage difference between the battery pack voltage and the DC bus; The output current of the charging control module is adjusted according to the voltage difference.

[0008] In some embodiments, the charging control module is provided with a plurality of silicon chain diodes; Adjusting the output current of the charging control module according to the voltage difference specifically includes: When the charging control module is activated, if the voltage difference is greater than the first voltage difference threshold... The initial output current of the charging control module is the first multiplier current; when Greater than the second voltage difference threshold and less than the first voltage difference threshold The initial output current of the charging control module is the second multiplier current; when the voltage difference is less than the second voltage difference threshold, the initial output current of the charging control module is determined to be the third multiplier current.

[0009] In some embodiments, adjusting the output current of the charging control module according to the voltage difference further includes: After the charging control module is started, the output current is detected. If the rate of decrease of the output current is less than a first rate threshold, a first preset number of silicon chain diodes are removed at a first time interval. If the rate of decrease of the output current is greater than a second rate threshold, the current number of silicon chain diodes connected is maintained until a second time interval is reached.

[0010] In some embodiments, adjusting the output current of the charging control module according to the voltage difference further includes: Before the charging control module is turned off, if the voltage difference is less than the fourth voltage difference threshold and the output current is less than the fourth multiplier current, the first preset number of silicon chain diodes are float-charged for a third time interval.

[0011] To achieve the above objectives, another aspect of the embodiments of this application proposes an online capacity-matching circuit for a storage battery, comprising: a first discharge module, a hot standby diode, and an inverter module; The first discharge module is connected to the DC bus and the AC grid, and is used to convert the DC power of the DC bus into AC power and feed it back to the AC grid if the DC bus voltage is greater than the upper voltage threshold in the core capacity mode. The input terminal of the hot standby diode is connected to the positive terminal of the battery, and the output terminal is connected to the DC bus. In the core capacity mode, if the DC bus voltage is less than or equal to the upper voltage threshold and greater than or equal to the lower voltage threshold, the battery supplies power to the DC bus. The inverter module is connected to the AC grid and the DC model. In the core capacity mode, if the DC bus voltage is less than the lower voltage threshold, it controls the power to be drawn from the AC grid to increase the DC bus voltage.

[0012] In some embodiments, the circuit further includes: a charging control module, with its input terminal connected to the DC bus and its output terminal connected to the battery; The charging control module is equipped with several silicon chain diodes, which are used to adjust the input voltage of the battery.

[0013] To achieve the above objectives, another aspect of this application proposes an online battery capacity assessment system based on multi-diode series unidirectional isolation, including the circuit and control circuit described in this embodiment. The control circuit is used to perform the method described in this embodiment to perform online battery capacity assessment.

[0014] To achieve the above objectives, another aspect of the present application provides a computer-readable storage medium storing a computer program product, which, when executed by a computer, implements the method described in this embodiment.

[0015] The embodiments of this application include at least the following beneficial effects: This application provides a method and related equipment for online capacity grading of batteries based on multi-diode series unidirectional isolation. The method includes: in capacity grading mode, controlling the battery to discharge to the DC bus with a preset current and monitoring the DC bus voltage; if the DC bus voltage is greater than an upper voltage threshold, converting the DC power of the DC bus to AC power and feeding it back to the AC power grid; if the DC bus voltage is less than or equal to the upper voltage threshold but greater than or equal to the lower voltage threshold, supplying power to the DC bus through the battery; if the DC bus voltage is less than the lower voltage threshold, controlling power to be drawn from the AC power grid to increase the DC bus voltage. This method distributes the released electrical energy by discharging the battery between capacity grading points to the DC bus and maintaining the DC bus voltage stability according to the upper and lower voltage thresholds, thereby reducing wasted electrical energy. Attached Figure Description

[0016] Figure 1 This is a flowchart of the online capacity verification method for batteries shown in this embodiment; Figure 2 This is a flowchart of the step of charging the battery in the method shown in this embodiment; Figure 3 This is a schematic diagram of the battery online capacity control circuit shown in this embodiment; Figure 4This is a circuit diagram of the online capacity-matching circuit for the battery shown in this embodiment; Figure 5 This is another circuit structure diagram of the battery online capacity control circuit shown in this embodiment. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit it. In the following description, when referring to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with those of this application; they are merely examples of apparatuses and methods consistent with some aspects of the embodiments of this application as detailed in the appended claims.

[0018] It is understood that the terms “first,” “second,” etc., used in this application may be used herein to describe various concepts, but unless otherwise stated, these concepts are not limited by these terms. These terms are only used to distinguish one concept from another. For example, without departing from the scope of the embodiments of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the words “if,” “when,” or “in response to a determination” as used herein may be interpreted as “when…” or “when…” or “in response to a determination.”

[0019] As used in this application, the terms "at least one", "multiple", "each", "any", etc., "at least one" includes one, two or more, "multiple" includes two or more, "each" refers to each of the corresponding multiples, and "any" refers to any one of the multiples.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0021] In related technologies, the general process for battery capacity verification in DC power systems is as follows: A diode and an electric control are used as the main controllers. After the electric control trips, the diode provides unidirectional isolation. This tripping of the electric control blocks the charger's charging circuit to the battery, allowing the battery to undergo capacity verification discharge. After the discharge is complete, the electric control is closed, and the charger resumes normal charging. This method results in an uncontrollable charging process and lacks protection for the discharged battery in a DC system loop network. During this process, the battery goes offline, and the safety of the DC bus cannot be guaranteed.

[0022] In view of this, embodiments of this application provide an online capacity assessment method and related equipment for a storage battery based on multi-diode series unidirectional isolation, which can recover and reuse the electrical energy released during the capacity assessment process, thereby reducing waste.

[0023] The online battery capacity verification method provided in this application relates to the field of information technology. This method can be applied to a terminal, a server, or can be software running on either a terminal or a server.

[0024] In some embodiments, the terminal may be a smartphone, tablet, laptop, desktop computer, smart speaker, smartwatch, or in-vehicle terminal, but is not limited thereto; the server may be configured as an independent physical server, or as a server cluster or distributed system composed of multiple physical servers, or as a cloud server providing basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, CDN, and big data and artificial intelligence platforms. The server may also be a node server in a blockchain network; the software may be an application that implements a scaling model construction method, but is not limited to the above forms.

[0025] This application can be used in a wide variety of general-purpose or special-purpose computer system environments or configurations. Examples include: personal computers, server computers, handheld or portable devices, tablet devices, multiprocessor systems, microprocessor-based systems, set-top boxes, programmable consumer electronics devices, network PCs, minicomputers, mainframe computers, and distributed computing environments including any of the above systems or devices. This application can be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform specific tasks or implement specific abstract data types. This application can also be practiced in distributed computing environments where tasks are performed by remote processing devices connected via a communication network. In distributed computing environments, program modules can reside in local and remote computer storage media, including storage devices.

[0026] Figure 1 This is a flowchart of the online capacity assessment method for a storage battery as shown in this embodiment.

[0027] This application provides an online capacity assessment method for batteries based on multi-diode series unidirectional isolation, applied to the capacity assessment of batteries in a DC power system, wherein the DC power system includes a DC bus and batteries connected to the DC bus.

[0028] See Figure 1The method includes: 101. In the core capacity mode, control the battery to discharge to the DC bus with a preset current, and monitor the DC bus voltage; 102. If the DC bus voltage is greater than the upper voltage threshold, the DC power of the DC bus is converted into AC power and fed back to the AC power grid; 103. If the DC bus voltage is less than or equal to the upper voltage threshold and greater than or equal to the lower voltage threshold, the DC bus is powered through the battery. 104. If the DC bus voltage is less than the lower voltage threshold, power is drawn from the AC grid to increase the DC bus voltage.

[0029] This embodiment distributes the released electrical energy from the battery cores to the DC bus by discharging between the cores and maintaining the DC bus voltage stability according to the upper and lower voltage thresholds, thereby reducing the wasted electrical energy from the cores.

[0030] In one embodiment, the method further includes: charging the battery via a charging control module while the battery is out of the capacity-controlled mode. It is understood that, after capacity control is completed, this embodiment recharges the battery after capacity discharge.

[0031] Figure 2 This is a flowchart of the step of charging the battery in the method described in this embodiment.

[0032] See Figure 2 The charging of the battery via the charging control module includes: 201. Monitor the voltage difference between the battery pack voltage and the DC bus; 202. Adjust the output current of the charging control module according to the voltage difference.

[0033] In one embodiment, the charging control module is provided with a plurality of silicon chain diodes. In this embodiment, the output voltage and output current of the charging control module are controlled by the number of silicon chain diodes connected, so as to avoid the undercharged battery being damaged by the initial charging current or the current of the runaway charging unit, thus preventing it from opening the circuit and better ensuring system safety and battery safety.

[0034] In one embodiment, adjusting the output current of the charging control module according to the voltage difference specifically includes: When the charging control module is started, if the voltage difference is greater than the first voltage difference threshold, the initial output current of the charging control module is determined to be the first multiplier current; if the voltage difference is greater than the second voltage difference threshold and less than the first voltage difference threshold, the initial output current of the charging control module is determined to be the second multiplier current; if the voltage difference is less than the second voltage difference threshold, the initial output current of the charging control module is determined to be the third multiplier current.

[0035] For example, the first voltage difference threshold is 50V, the second voltage difference threshold is 30V, the first multiplier current is 0.08C to 0.1C, the second multiplier current is 0.1C, and the third multiplier current is 0.1C to 0.12C.

[0036] In this embodiment, adjusting the output current of the charging control module according to the voltage difference includes: after the full capacity discharge is completed, the system automatically collects three types of data—remaining battery pack capacity (SOC), individual cell voltage dispersion (…). ), bus voltage and battery pack voltage difference ( A "prediction model for the initial investment quantity of silicon chain" is established through a built-in algorithm.

[0037] The model for predicting the initial investment in the silicon chain is as follows: When the charging control module is activated, when the voltage difference... The initial output current of the charging control module is set to 0.08C to 0.1C to avoid current surges under extreme voltage differences; when The voltage difference The initial output current of the charging control module is determined to be 0.1C, and constant current charging is maintained to protect the battery; when the voltage difference... The initial output current of the charging control module is set to 0.1C to 0.12C to improve charging efficiency.

[0038] After the charging control module is activated, the output current is detected. If the rate of decrease of the output current is less than a first rate threshold, a first preset number of silicon chain diodes are deactivated at a first time interval. Simultaneously, the voltage of all individual battery cells is monitored to ensure that no single cell voltage exceeds 2.4V (the overcharge threshold for lead-acid batteries). If the rate of decrease of the output current is greater than a second rate threshold, the current number of silicon chain diodes connected is maintained for a second time interval. At this point, the current drops sharply, indicating that the battery is fast-charged to saturation. Deactivation continues only after the current stabilizes. Specifically, the first preset number is ten percent of the total number of silicon chain diodes.

[0039] Before the charging control module is shut down, if the voltage difference is less than the fourth voltage difference threshold (5V) and the output current is less than the fourth rate current (0.05C), the first preset number (10%) of the silicon chain diodes are float-charged for the third time interval. After eliminating the polarization voltage inside the battery pack, the main circuit switching is completed to avoid instantaneous voltage fluctuations during switching.

[0040] In one embodiment, if the individual cell voltage dispersion Prioritize adjusting the local voltage drop of the silicon chain (rather than shutting it down entirely), and use miniature shunt resistors to assist in relieving pressure in the branches where individual cells have high voltage, so as to ensure that the batteries in the group are charged evenly.

[0041] Figure 3 This is a schematic diagram of an online capacity-matching circuit for a battery provided in this embodiment.

[0042] Please see Figure 3 The circuit in this embodiment includes: a first discharge module, a hot standby diode, and an inverter module.

[0043] The first discharge module is connected to the DC bus and the AC grid, and is used to convert the DC power of the DC bus into AC power and feed it back to the AC grid if the DC bus voltage is greater than the upper voltage threshold in the core capacity mode. The input terminal of the hot standby diode is connected to the positive terminal of the battery, and the output terminal is connected to the DC bus. In the core capacity mode, if the DC bus voltage is less than or equal to the upper voltage threshold and greater than or equal to the lower voltage threshold, the battery supplies power to the DC bus. The inverter module is connected to the AC grid and the DC model. In the core capacity mode, if the DC bus voltage is less than the lower voltage threshold, it controls the power to be drawn from the AC grid to increase the DC bus voltage.

[0044] Understandably, in the normal operating mode of the battery, the battery discharges through the second discharge module ( Figure 3 An electric switch (not shown) connects the DC bus and the battery to connect the DC bus and the battery in the operating mode.

[0045] Figure 4 This is a circuit structure diagram of the circuit provided in this embodiment.

[0046] See Figure 4In capacity mode, the first discharge module is equipped with a DC / AC inverter module and an electric control switch DK13. When the DC bus voltage is greater than the upper voltage threshold, it converts the DC power from the DC bus into AC power and feeds it back to the AC grid. When the DC bus voltage is less than the lower voltage threshold, the inverter module acts as an AC / DC inverter, drawing power from the AC grid to increase the DC bus voltage.

[0047] In normal operating mode, the circuit is connected to the DC bus and the battery via the electric operating switch DK11 of the second discharge module.

[0048] In one embodiment, such as Figure 4 As shown, the circuit also includes a charging control module, with its input terminal connected to the DC bus and its output terminal connected to the battery. The charging control module is equipped with several silicon chain diodes. These silicon chain diodes form a thyristor chain, used to adjust the input voltage of the battery. After exiting the core capacity mode, the charging control module is connected via switch DK12.

[0049] Understandably, after exiting the core capacity mode, the DC bus obtains power from the AC grid through the inverter, and the battery is used to stabilize the voltage of the DC bus. When the voltage of the DC bus is too high, it is charged, and when the voltage of the DC bus is too low, it is discharged.

[0050] Figure 5 This is another circuit structure diagram of the circuit provided in this embodiment.

[0051] See Figure 5 In this embodiment of the application, two battery packs can be connected in parallel via the online capacity assessment circuit. Only one battery pack can be assessed at a time; when one battery pack is under capacity assessment, the other battery pack's capacity assessment is disabled.

[0052] This embodiment also provides an online battery capacity assessment system based on multi-diode series unidirectional isolation, including the circuit and control circuit described in the above embodiments. The control circuit is used to perform online battery capacity assessment as described in the above embodiments.

[0053] This embodiment also provides a computer-readable storage medium storing a computer program product, which, when executed by a computer, implements the methods described in the above embodiments.

[0054] The embodiments described in this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided by the embodiments of this application. As those skilled in the art will know, with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by the embodiments of this application are also applicable to similar technical problems.

[0055] Those skilled in the art will understand that the technical solutions shown in the figures do not constitute a limitation on the embodiments of this application, and may include more or fewer steps than shown, or combine certain steps, or different steps.

[0056] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0057] Those skilled in the art will understand that all or some of the steps in the methods disclosed above, as well as the functional modules / units in the systems and devices, can be implemented as software, firmware, hardware, or suitable combinations thereof.

[0058] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0059] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0060] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of the units described above is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0061] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0062] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0063] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes multiple instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing programs, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0064] The preferred embodiments of the present application have been described above with reference to the accompanying drawings, but this does not limit the scope of the claims of the present application. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and substance of the embodiments of the present application shall be within the scope of the claims of the present application.

Claims

1. A method for online capacity assessment of a battery based on multi-diode series unidirectional isolation, characterized in that, This is used for capacity assessment of batteries in a DC power system, wherein the DC power system includes a DC bus and batteries connected to the DC bus; The method includes: In core capacity mode, the battery is controlled to discharge to the DC bus at a preset current, and the DC bus voltage is monitored; If the DC bus voltage is greater than the upper voltage threshold, the DC power of the DC bus will be converted into AC power and fed back to the AC power grid; If the DC bus voltage is less than or equal to the upper voltage threshold and greater than or equal to the lower voltage threshold, the DC bus is powered through the battery. If the DC bus voltage is lower than the lower voltage threshold, power is drawn from the AC grid to increase the DC bus voltage.

2. The online capacity assessment method for a storage battery as described in claim 1, characterized in that, The method further includes: When the battery is out of capacity mode, the battery is charged via the charging control module.

3. The online capacity assessment method for a storage battery as described in claim 2, characterized in that, The charging of the battery via the charging control module specifically includes: Monitor the voltage difference between the battery pack voltage and the DC bus; The output current of the charging control module is adjusted according to the voltage difference.

4. The online capacity assessment method for a storage battery as described in claim 3, characterized in that, The charging control module is equipped with several silicon chain diodes; Adjusting the output current of the charging control module according to the voltage difference specifically includes: When the charging control module is started, if the voltage difference is greater than the first voltage difference threshold, the initial output current of the charging control module is determined to be the first multiplier current; if the voltage difference is greater than the second voltage difference threshold and less than the first voltage difference threshold, the initial output current of the charging control module is determined to be the second multiplier current; if the voltage difference is less than the second voltage difference threshold, the initial output current of the charging control module is determined to be the third multiplier current.

5. The online capacity assessment method for a storage battery as described in claim 3, characterized in that, Adjusting the output current of the charging control module according to the voltage difference further includes: After the charging control module is started, the output current is detected. If the rate of decrease of the output current is less than a first rate threshold, a first preset number of silicon chain diodes are removed at a first time interval. If the rate of decrease of the output current is greater than a second rate threshold, the current number of silicon chain diodes connected is maintained until a second time interval is reached.

6. The online capacity assessment method for a storage battery as described in claim 3, characterized in that, Adjusting the output current of the charging control module according to the voltage difference further includes: Before the charging control module is turned off, if the voltage difference is less than the fourth voltage difference threshold and the output current is less than the fourth multiplier current, the first preset number of silicon chain diodes are float-charged for a third time interval.

7. A battery online capacity assessment circuit, characterized in that, Includes a first discharge module, a hot standby diode, and an inverter module; The first discharge module is connected to the DC bus and the AC grid, and is used to convert the DC power of the DC bus into AC power and feed it back to the AC grid if the DC bus voltage is greater than the upper voltage threshold in the core capacity mode. The input terminal of the hot standby diode is connected to the positive terminal of the battery, and the output terminal is connected to the DC bus. In the core capacity mode, if the DC bus voltage is less than or equal to the upper voltage threshold and greater than or equal to the lower voltage threshold, the battery supplies power to the DC bus. The inverter module is connected to the AC grid and the DC model. In the core capacity mode, if the DC bus voltage is less than the lower voltage threshold, it controls the power to be drawn from the AC grid to increase the DC bus voltage.

8. The circuit as described in claim 7, characterized in that, The circuit also includes a charging control module, with its input terminal connected to the DC bus and its output terminal connected to the battery. The charging control module is equipped with several silicon chain diodes, which are used to adjust the input voltage of the battery.

9. A battery online capacity assessment system based on multi-diode series unidirectional isolation, characterized in that, It includes a control circuit and the circuit according to any one of claims 7 to 8, wherein the control circuit is used to perform the method according to any one of claims 1 to 6.

10. A computer-readable storage medium, characterized in that, The device contains a computer program product that, when executed by a computer, implements the method described in any one of claims 1 to 6.

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