Bidirectional parallel storage battery capacity checking system and method

Abstract

The invention provides a bidirectional parallel storage battery capacity checking system and method, and relates to the field of battery capacity checking, and the system comprises a station control system, a plurality of direct current buses, an alternating current bus, a plurality of storage battery packs, a battery optimizer and a bidirectional charging and discharging module, and is used for realizing storage, charging and discharging management and online capacity checking of storage batteries. The storage battery pack comprises a plurality of battery modules connected in parallel, and each battery module comprises storage batteries managed in pairs and a charging and discharging control circuit and is used for managing the charging and discharging states of the storage batteries. According to the capacity checking system and method provided by the invention, capacity checking is allowed to be carried out on a single battery pack, the storage batteries needing capacity checking can exit independently, and other battery packs continue to supply power normally under the condition that the overall power supply is not influenced, so that the parallel connection mode not only avoids power interruption and resource waste, but also realizes fine management of the battery packs, and the power supply efficiency is improved. The service life of the storage battery is prolonged, and the continuity and the stability of a power system are ensured.

Description

Technical Field

[0001] The present application relates to the field of battery capacity evaluation, and in particular to a bidirectional parallel battery capacity evaluation system and method. Background Art

[0002] Existing nuclear capacity technology has exposed many deficiencies in practical applications. Especially when multiple groups of batteries are connected in series, the maintenance efficiency is low, the operating cost is high, and the energy consumption remains high, which brings many challenges in daily operation and maintenance.

[0003] First, traditional technologies lack effective intelligent management methods, resulting in difficult operation and maintenance. They rely on manual operations, which not only increases the risk of errors but also makes maintenance costs high. Secondly, the bus voltage in the series battery system is greatly affected by the state of a single battery, and there is a risk of bus voltage loss, which affects the stability of the system and the continuity of power supply. In addition, there are compatibility issues in the parallel management of batteries of different brands. Due to the large differences in the characteristics and performance of batteries of different brands, it is difficult to achieve unified management and control with traditional technologies, which makes the compatibility and coordinated operation of multi-brand battery systems a major problem. Summary of the invention

[0004] The present application aims to solve one of the technical problems in the related art at least to some extent.

[0005] To this end, the first purpose of this application is to propose a bidirectional parallel battery core capacity system.

[0006] The second objective of the present application is to provide a method for increasing the capacity of bidirectional parallel batteries.

[0007] The third objective of the present application is to provide an electronic device.

[0008] A fourth objective of the present application is to provide a computer-readable storage medium.

[0009] A fifth object of the present application is to provide a computer program product.

[0010] To achieve the above-mentioned purpose, the first embodiment of the present application proposes a bidirectional parallel battery core capacity system, comprising: The station control system is used to connect various DC monitoring systems through Ethernet network to achieve overall monitoring of the system; A plurality of DC buses, each of which is connected to a corresponding DC monitoring to provide transmission and distribution of DC power; AC busbar, connected to the grid side, used to supply power to AC type electrical equipment or converters; A plurality of battery packs, respectively connected to the corresponding DC busbars, for storing and providing DC power, wherein the battery pack comprises a plurality of battery modules connected in parallel, each battery module comprises a pair of managed batteries and a charge and discharge control circuit for managing the charge and discharge state of the battery; A plurality of battery optimizers are connected to the corresponding battery packs to realize online repair, real-time data monitoring, charge and discharge balance and fault protection of single cells to ensure the overall efficiency and service life of the system; A plurality of bidirectional charge and discharge modules are connected between the AC bus, the corresponding battery pack and the DC bus, and are used to convert AC power into DC power and provide power support for the DC bus, or to charge and discharge the battery pack when necessary to realize online capacity verification of the battery and provide power support for the AC load.

[0011] Optionally, in the battery pack, the battery modules connected in parallel are connected to the input and output circuits of other battery modules of each corresponding branch through a DC / DC circuit or a bidirectional AC / DC circuit, and there is no direct connection between the batteries in different branches. The structure between the batteries is indirect parallel connection, and there will be no loop current phenomenon; In the battery modules connected in parallel, the charge and discharge control circuit replaces the inspection device of the traditional battery pack, and enables the battery and the charge and discharge control circuit to be managed in pairs, which is convenient for switching on and off of a single battery.

[0012] Optional, including: When the voltage sources of the battery modules connected in parallel operate normally, the circuit supplies power to the load with AC power; When the AC power fails, the batteries in the battery modules connected in parallel convert the voltage through the boost DC / DC conversion module to supply power to the load instead of the AC power circuit; When the AC power resumes normal operation, the battery in the battery module is charged through the Buck circuit and a voltage source is provided to the load. The battery is connected to the load DC bus through the Boost circuit to supply power to the bus at any time.

[0013] Optionally, the battery optimizer is specifically used for: Balancing the charge and discharge states of each battery module in the battery pack, and dynamically adjusting the charge and discharge current of each battery module to ensure that the charge states of each battery module are balanced; Dynamically adjust the charge and discharge parameters of each battery under different usage conditions, give priority to using batteries in better condition according to the health status of each battery, and reduce excessive use of deteriorated batteries; The temperature, voltage and current of each battery module are monitored. When an abnormal situation is detected, the abnormal battery module is automatically controlled to exit the parallel system and perform independent pulse repair and trickle charging.

[0014] To achieve the above-mentioned purpose, a second embodiment of the present application proposes a bidirectional parallel battery capacity evaluation method, comprising: Determine the nominal capacity of the battery that needs to be verified and measure the current battery voltage; Control the bidirectional charge and discharge module to adjust the output power so that the corresponding battery discharges at a constant current of 0.1C; Detecting the current and voltage parameters of the battery, and recording the discharged capacity and continuous discharge time of the battery; Using Lagrange interpolation method to determine whether the battery voltage meets the discharge termination voltage, if so, exit the discharge capacity verification process, otherwise, execute the next step; Determine whether the capacity discharged by the battery reaches the target value, if so, exit the discharge capacity verification process, otherwise, execute the next step; Determine whether the continuous discharge time of the battery reaches the discharge protection time or whether the temperature is over, if so, exit the discharge capacity verification process, otherwise, adjust the discharge current target value of the battery, and control the bidirectional charge and discharge module to adjust the output power according to the discharge current target value, so that the corresponding battery performs constant current discharge at the discharge current target value, and re-executes the discharge process; When the battery exits the discharge capacity verification process, the bidirectional charge and discharge module is controlled to adjust the output power so that the corresponding battery is charged with a constant current at a charging current target value, and the charging state of the battery is detected and recorded until the capacity verification is completed.

[0015] Optionally, when the battery is discharged to its core capacity, the method includes: The electric energy released by the battery is controlled to first flow to the load connected in parallel therewith, directly supplying power to the load equipment. When the load demand is small and there is surplus electric energy, the remaining electric energy is fed back to the AC power grid through the bidirectional charging and discharging module.

[0016] Optionally, the using of the Lagrange interpolation method to determine whether the battery voltage meets the discharge termination voltage includes: S1. When the battery is discharged to its nuclear capacity, the terminal voltage of the battery is recorded once every hour; S2. If the capacity decay rate of the entire battery group does not meet the preset requirements and the total discharge time is not less than four hours, the cubic Lagrange interpolation polynomial of the battery terminal voltage is constructed using the last four recorded data; if the capacity decay rate of the entire battery group does not meet the requirements and the total discharge time is less than four hours, the Lagrange interpolation polynomial of the corresponding order of the battery terminal voltage is constructed using all the data; S3, estimating the terminal voltage of the battery under the specified total discharge time according to the constructed Lagrange interpolation polynomial, if the terminal voltage estimate is greater than the last actual terminal voltage record value, constructing a Lagrange interpolation using the last two actual terminal voltage record values, and correcting the terminal voltage estimate according to the Lagrange interpolation to obtain a voltage correction value; S4. Compare and judge the voltage correction value with the discharge termination voltage.

[0017] Optionally, also include: If the terminal voltage estimation value is not greater than the last actual terminal voltage record value, return to step S2.

[0018] To achieve the above-mentioned purpose, the third aspect of the present application provides an electronic device, including: a processor, and a memory communicatively connected to the processor; The memory stores computer-executable instructions; The processor executes the computer-executable instructions stored in the memory to implement the method as described in any one of the second aspects.

[0019] To achieve the above-mentioned purpose, the fourth aspect embodiment of the present application proposes a computer-readable storage medium, in which computer-readable storage medium is stored computer execution instructions, and when the computer execution instructions are executed by a processor, they are used to implement the method as described in any one of the second aspects.

[0020] To achieve the above-mentioned purpose, the fifth aspect of the present application proposes a computer program product, which implements any method in the second aspect when executed by a processor.

[0021] The technical solution provided by the embodiments of the present application brings at least the following beneficial effects: 1. When the battery is discharged, the released electric energy first flows to the load connected in parallel with it, directly supplying power to the load equipment. If the load's power demand is balanced with the power provided by the battery, the power can be fully consumed to avoid power waste. When the load demand is small and there is surplus power, the remaining power will be fed back to the grid through the bidirectional AC / DC converter, which not only effectively avoids power waste, but also reduces the resource consumption pressure generated during the power generation process by improving energy utilization efficiency.

[0022] 2. The traditional battery capacity verification method usually requires operators to manually start and stop the knife switch. The process needs to be strictly operated according to the prescribed procedures, and usually involves tedious steps such as issuing additional work tickets. The whole process is complicated and inefficient. For this reason, the present application eliminates the switch knife switch device on the battery side in design, and realizes automatic capacity verification and discharge of the battery through electronic and intelligent methods, and no longer relies on manual operation. The steps and processes of capacity verification are greatly simplified, work efficiency is improved, and the risk of human operational errors is reduced. In addition, since there is no need to interrupt the power supply, the system can achieve non-inductive discharge and capacity verification of the battery, ensuring the stability and continuity of the system operation.

[0023] 3. The parallel battery discharge capacity verification method has significant advantages over the series method. The parallel battery system allows the verification of the capacity of a single battery pack without affecting the overall power supply. The battery that needs to be verified can be withdrawn independently, and other battery packs continue to supply power normally, thereby improving the flexibility and operating efficiency of the system. The parallel method not only avoids power outages and waste of resources, but also realizes the refined management of battery packs, which helps to extend the service life of the battery and ensure the continuity and stability of the power system.

[0024] 4. The Lagrange-based voltage limit estimation method optimizes the interpolation of the discharge curve, so that the discharge voltage limit can be predicted more accurately during the core capacity discharge process. It reduces the reliance on empirical values, avoids the estimation deviation caused by factors such as battery aging and ambient temperature changes in traditional methods, and improves the voltage prediction accuracy and reliability during the discharge process. In addition, the Lagrange interpolation method can effectively handle nonlinear discharge characteristics, making the voltage limit estimation more adaptable, which helps to extend battery life and ensure the safety and stability of the system.

[0025] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which: Figure 1 A schematic diagram of the structure of a bidirectional parallel battery core capacity system provided in an embodiment of the present application; Figure 2 A schematic diagram of the internal structure of a battery pack provided in an embodiment of the present application; Figure 3 A schematic flow chart of a bidirectional parallel battery capacity control method provided in an embodiment of the present application; Figure 4 A schematic diagram of a process for determining battery voltage using the Lagrange interpolation method provided in an embodiment of the present application; Figure 5 A schematic diagram of the waveform of the change of the discharge current and charge of the core capacitor during the discharge process measured by experiments provided in the embodiment of the present application; Figure 6 A schematic diagram of a battery voltage waveform of a core capacity discharge current and a core capacity charge during a discharge process measured experimentally provided in an embodiment of the present application. DETAILED DESCRIPTION

[0027] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0028] The DC power supply system is used in power plants. Various substations are mainly composed of battery packs, charging devices, DC feeder panels, DC distribution cabinets, DC power supply monitoring devices, DC branch feeders, etc., which provide safe and reliable working power for various subsystems such as relay protection devices, circuit breaker tripping and closing, signal systems, DC chargers, UPS, communications, etc. As an important power source for the DC power supply system in power plants, substations and converter stations, the battery pack provides uninterrupted power for relay protection, communication control, emergency lighting, etc. Its power supply capacity is the last guarantee for the stable operation of plant and station equipment. Nuclear capacity discharge is the most effective means recognized to date to measure the power supply capacity of batteries. Most traditional battery packs are connected in series and use voltage balancing. It is inconvenient to repair and replace, and the maintenance cost is high. When replacing a battery, the entire group needs to be disconnected, which reduces reliability. The voltage balancing effect depends largely on the characteristic differences of the battery cells themselves. If there are large differences in parameters such as capacity and internal resistance during the production process of the battery, it is difficult to ensure the consistency of the state of each battery during the charge and discharge cycle by relying solely on voltage balancing.

[0029] The existing solutions have the following disadvantages: (1) Existing core capacity technologies mostly use empirical values ​​as reference when setting the discharge limit voltage, which results in certain problems in voltage accuracy; (2) Traditional on-site nuclear capacity discharge is done manually, which is cumbersome and consumes a lot of manpower and material resources; (3) Traditional core capacity technology places the battery pack in an offline state, which cannot provide power supply protection for the bus voltage loss of a single battery pack and the DC load power supply; (4) The current online capacity verification method for battery packs only verifies the capacity of the entire battery pack and cannot detect individual batteries. In addition, it is easy for the battery status to fail to meet the specification requirements during the test, thereby affecting the battery life and the stability of the battery pack operation.

[0030] In general, the existing nuclear capacity technology has exposed many deficiencies in practical applications, especially when multiple groups of batteries are connected in series, the maintenance efficiency is low, the operating cost is high, and the energy consumption remains high, which brings many challenges in daily operation and maintenance. First, the traditional technology lacks effective intelligent management methods, which makes operation and maintenance difficult and relies on manual operation, which not only increases the risk of errors, but also makes maintenance costs high. Secondly, the bus voltage in the series battery system is greatly affected by the state of a single battery, and there is a risk of bus voltage loss, which affects the stability of the system and the continuity of power supply, and there are compatibility issues in the parallel management of batteries of different brands. Due to the large differences in the characteristics and performance of batteries of various brands, it is difficult for traditional technologies to achieve unified management and control, which makes the compatibility and coordinated operation of multi-brand battery systems a major problem. In addition, there are accuracy issues in the value of the discharge voltage limit.

[0031] To address this problem, an embodiment of the present application provides a bidirectional parallel battery capacity core system and method. The optimized capacity core method can achieve automated monitoring and operation and maintenance by improving the control algorithm and adding an intelligent management module, significantly reducing the need for manual intervention and improving the overall efficiency of the system. At the same time, a more flexible parallel management method is adopted. Even when multiple brands of batteries coexist, the system can intelligently match them according to the battery characteristics to achieve efficient compatibility. These improvements have greatly reduced energy consumption and reduced equipment and operation and maintenance costs. In addition, the optimized technology can monitor and dynamically adjust the bus voltage in real time, effectively preventing bus pressure loss and ensuring safe and stable operation of the system.

[0032] Figure 1 This is a schematic diagram of the structure of a bidirectional parallel battery core capacity system provided in an embodiment of the present application. Figure 1 As shown, the system includes: a station control system, multiple DC buses (i.e. Figure 1 The I busbar and II busbar shown in the figure), AC busbar (i.e. Figure 1 The AC busbar shown in the figure), multiple battery packs, multiple battery optimizers, and multiple bidirectional charging and discharging modules.

[0033] In an embodiment of the present application, the station control system is used to connect each DC monitor through an Ethernet network to achieve overall monitoring of the system; each DC bus is respectively connected to the corresponding DC monitor to provide transmission and distribution of DC power; the AC bus is connected to the grid side to power any AC type of electrical equipment or converter; multiple battery packs are respectively connected to the corresponding DC bus for storing and providing DC power, wherein the battery pack includes multiple battery modules connected in parallel, each battery module includes a group of managed batteries and a charge and discharge control circuit for managing the charge and discharge status of the battery; multiple battery optimizers are connected to the corresponding battery packs to achieve online repair, real-time data monitoring, charge and discharge balance and fault protection of single cells to ensure the overall efficiency and service life of the system; multiple bidirectional charge and discharge modules are connected between the AC bus, the corresponding battery pack and the DC bus to convert AC power into DC power and provide power support for the DC bus, or charge and discharge the battery pack when necessary to achieve online capacity verification of the battery and provide power support for the AC load.

[0034] It can be understood that multiple sets of bidirectional charging and discharging modules are connected in parallel in a DC system to form a parallel DC power supply device, which provides a DC power supply with redundant backup for the DC bus in this application.

[0035] In addition, in the embodiment of the present application, the battery optimizer can realize online repair and real-time data monitoring of single cells, and can extend the service life of the entire battery group and improve the life cycle of the entire device by optimizing the capacity burden of the intermediate battery and independent battery management through algorithms. The functions of the battery optimizer are as follows: 1. Balance the charge and discharge status of each battery module in the battery pack, and dynamically adjust the charge and discharge current of each battery module to ensure that the charge status of each battery module is balanced.

[0036] In the bidirectional parallel battery core capacity system proposed in this application, each battery module may have different initial states, capacities, health states, etc. The battery optimizer can ensure the balance of the state of charge (SOC) of each battery module by dynamically adjusting the charge and discharge current of each battery module, thereby extending the service life of the entire system.

[0037] 2. Dynamically adjust the charge and discharge parameters of each battery under different usage conditions, give priority to using batteries in better condition according to the health status of each battery, and reduce excessive use of deteriorated batteries.

[0038] In the embodiment of the present application, the battery optimizer can dynamically adjust the charge and discharge parameters of each battery under different usage conditions to maximize the efficiency of the entire battery system. It can give priority to using batteries in better condition according to the health status of the battery, reduce the overuse of deteriorated batteries, and improve the overall efficiency.

[0039] 3. Monitor the temperature, voltage and current of each battery module. When an abnormal situation is detected, the abnormal battery module is automatically controlled to exit the parallel system and perform independent pulse repair and trickle charging.

[0040] In the embodiment of the present application, the battery optimizer also has a monitoring function, which can monitor the temperature, voltage, current and other parameters of each battery module. Once an abnormal situation is detected, such as battery over-temperature, over-voltage or over-current, the battery optimizer can respond in time to protect the battery module and prevent danger.

[0041] In addition, if Figure 2 As shown, in the battery pack of the present application, the parallel battery modules are connected to the input and output circuits of other battery modules of each corresponding branch through a DC / DC circuit or a bidirectional AC / DC circuit. There is no direct connection between the batteries in different branches. The structural mode between the batteries is indirect parallel, and the circuit circulation phenomenon will not occur.

[0042] In the parallel battery module proposed in the present application, the inspection device of the traditional battery pack is replaced by the charge and discharge control circuit, and the battery and the charge and discharge control circuit are managed in pairs, which facilitates the switching of a single battery, increases the safety of the system and the convenience of maintenance.

[0043] With the battery pack proposed in the present embodiment, when the voltage source of the parallel battery modules operates normally, the circuit is powered by AC power to the load; when the AC power is lost, the batteries in the parallel battery modules convert the voltage through the boost DC / DC conversion module to replace the AC circuit to power the load; when the AC power resumes normal operation, the batteries in the battery modules are charged through the Buck circuit and a voltage source is provided to the load, and the batteries are connected to the load DC bus through the Boost circuit so as to supply power to the bus at any time.

[0044] According to the bidirectional parallel battery capacity core system proposed in the above embodiment, this embodiment also provides a bidirectional parallel battery capacity core method, which calculates the battery voltage and current parameters sampled by the battery sampling module in the battery optimizer and the current required for 0.1C core capacity, sends instructions to the bidirectional charge and discharge module, and makes corresponding adjustments as the battery voltage decreases, ensuring that the battery discharge current is basically maintained at 0.1C. The control accuracy depends on the voltage and current errors of the battery acquisition module on the one hand, and on the other hand, a negative feedback closed-loop algorithm is used to adjust the instruction value.

[0045] Figure 3 This is a flow chart of a bidirectional parallel battery capacity control method provided in an embodiment of the present application. The capacity control method can be referred to as Figure 3 Specifically, the capacity verification method includes the following steps: Step 101, determine the nominal capacity of the battery that needs to be verified, and measure the current voltage of the battery.

[0046] In the embodiment of the present application, when it is necessary to conduct a core capacity charge and discharge experiment on a battery, the nominal capacity of the target battery (i.e., the design capacity of the battery) is first determined to facilitate subsequent capacity calculation. Then, the current battery voltage is measured as the starting state to monitor the voltage change during the discharge process to ensure the accuracy and safety of the test.

[0047] Step 102, controlling the bidirectional charge and discharge module to adjust the output power so that the corresponding battery discharges at a constant current of 0.1C.

[0048] In the embodiment of the present application, the monitor sends an inversion instruction to the bidirectional charge and discharge module, thereby controlling the bidirectional charge and discharge module to adjust the output power. It can be understood that the monitor is Figure 1 The structure in the station control system.

[0049] By controlling the bidirectional charge and discharge module to adjust the output power, the battery is kept discharged at a constant current of 0.1C (i.e., constant current discharge, the current size is 10% of the nominal capacity of the battery). This constant current discharge helps to accurately measure the actual capacity of the battery. The discharge current can be maintained stable through a closed-loop control feedback system to ensure the constancy of the discharge process.

[0050] Step 103, detecting the current and voltage parameters of the battery, and recording the discharged capacity and continuous discharge time of the battery.

[0051] In the embodiment of the present application, during the discharge process, the bidirectional parallel battery core capacity detects the current and voltage parameters of the battery in real time, and records the discharge capacity (discharged electricity) and the duration of continuous discharge of the battery. These data are used to calculate the total discharge capacity and discharge efficiency of the battery to evaluate the health status and actual capacity of the battery.

[0052] Step 104, using Lagrange interpolation method to determine whether the battery voltage meets the discharge termination voltage, if so, exit the discharge capacity verification process, otherwise, execute the next step.

[0053] In the embodiment of the present application, the system uses the Lagrange interpolation method to interpolate the collected voltage data to predict whether the battery voltage is about to reach the set discharge termination voltage. If the voltage has reached or is about to reach the termination voltage, the discharge process is terminated, the capacity verification process is exited, and the battery is prevented from over-discharging. If the voltage has not reached the termination voltage, the next step is continued, that is, step 105 is executed.

[0054] Step 105, determine whether the capacity discharged by the battery reaches the target value, if so, exit the discharge capacity verification process, otherwise, execute the next step.

[0055] In the embodiment of the present application, the system checks whether the discharge capacity of the battery reaches the preset target capacity. If the discharged capacity has reached the target value, it means that the battery capacity verification test is completed and the discharge verification process is exited. If the target value is not reached, it means that the discharge process is not completed and the next step is continued, that is, step 106 is executed.

[0056] Step 106, determine whether the continuous discharge time of the battery reaches the discharge protection time or whether it is overheated. If so, exit the discharge capacity verification process. Otherwise, adjust the discharge current target value of the battery, and control the bidirectional charge and discharge module to adjust the output power according to the discharge current target value, so that the corresponding battery performs constant current discharge at the discharge current target value, and re-executes the discharge process.

[0057] In the embodiment of the present application, the system detects whether the discharge time of the battery exceeds the set protection time, or whether the temperature is too high. If any of the conditions are met, the discharge process is stopped immediately to protect the battery from damage. If the protection condition is not met, the system adjusts the target value of the discharge current according to the current discharge state, controls the bidirectional charge and discharge module to adjust the output power, continues to discharge with the newly set constant current discharge current, and re-executes the discharge process to ensure that the battery continues to discharge within a safe range.

[0058] Step 107, when the battery exits the discharge capacity verification process, the bidirectional charge and discharge module is controlled to adjust the output power so that the corresponding battery is charged with a constant current at the charging current target value, and the charging state of the battery is detected and recorded until the capacity verification is completed.

[0059] In the embodiment of the present application, when the battery discharge capacity verification process is completed, the system switches to the charging mode, controls the output power of the bidirectional charge and discharge module, and enables the battery to be charged at a preset charging current target value with a constant current. The system simultaneously monitors and records the voltage, current, and charging status of the battery during the charging process until the battery is fully charged or reaches the end condition of the capacity verification. This charging process ensures that the battery is restored to a full power state after the capacity verification test, which is convenient for subsequent use.

[0060] Figure 4 The flowchart of using Lagrange interpolation method to determine battery voltage provided in the embodiment of the present application can be used as a reference. Specifically, step 104 also includes the following steps: S1. When the battery is discharged to its nuclear capacity, record the terminal voltage of the battery once every hour.

[0061] In the embodiment of the present application, during the core capacity discharge process of the battery, the terminal voltage of the battery is recorded every hour, and the data recording is stopped when the specified test time is reached or the test is terminated early because the battery capacity does not meet the requirements. These regularly recorded data are used for subsequent analysis to grasp the change trend of the battery voltage, ensure that the discharge process is controlled, and avoid over-discharge.

[0062] S2. If the capacity decay rate of the entire battery group does not meet the preset requirements and the total discharge time is not less than four hours, use the last four recorded data to construct a cubic Lagrange interpolation polynomial of the battery terminal voltage; if the capacity decay rate of the entire battery group does not meet the requirements and the total discharge time is less than four hours, use all the data to construct a Lagrange interpolation polynomial of the corresponding order of the battery terminal voltage.

[0063] In the embodiment of the present application, it is checked whether the capacity decay rate of the entire battery group meets the preset requirements, and it is determined whether the total discharge time reaches four hours. According to the determination result, appropriate data is selected to construct the Lagrange interpolation polynomial.

[0064] If the capacity decay rate does not meet the preset requirements and the total discharge time is not less than four hours, the voltage data of the last four records are selected and a cubic Lagrange interpolation polynomial is constructed using these data. The cubic interpolation polynomial can accurately fit the trend of voltage drop.

[0065] If the capacity decay rate does not meet the preset requirements and the total discharge time is less than four hours, a Lagrange interpolation polynomial of the corresponding order is constructed using all recorded data. Due to the small number of data points, the interpolation of the corresponding order can more accurately reflect the voltage change.

[0066] S3. Estimate the terminal voltage of the battery under the specified total discharge time according to the constructed Lagrange interpolation polynomial. If the terminal voltage estimate is greater than the last actual terminal voltage record value, use the last two actual terminal voltage record values ​​to construct a Lagrange interpolation, and correct the terminal voltage estimate according to the Lagrange interpolation to obtain a voltage correction value.

[0067] In the embodiment of the present application, the constructed Lagrange interpolation polynomial is used to estimate the terminal voltage value of the battery under the specified total discharge time. Then, a judgment is made based on the estimation result.

[0068] Specifically, if the estimated terminal voltage value is higher than the last actually recorded terminal voltage, it means that the interpolation result may be biased. The last two actually recorded terminal voltage data will be used to construct a first Lagrange interpolation (i.e., linear interpolation) to correct the previous estimated voltage value to obtain a more accurate voltage correction value.

[0069] If the estimated terminal voltage value is not higher than the terminal voltage actually recorded last time, it means that the interpolation estimated value is reasonable, and the process returns to step S2 to continue detecting and recording the battery terminal voltage to ensure the accuracy of subsequent estimations.

[0070] S4. Compare and judge the voltage correction value with the discharge termination voltage.

[0071] In the embodiment of the present application, the obtained voltage correction value is compared with the preset discharge termination voltage.

[0072] If the corrected voltage value is lower than the discharge termination voltage, it is judged that the discharge process should be terminated to protect the battery from damage caused by excessive discharge; if the corrected voltage value is higher than or equal to the discharge termination voltage, it means that the battery voltage is still within the safe range and the discharge capacity increase process can continue.

[0073] In addition, the present application experimentally measures the waveforms of the discharge current and charge of the core capacitor and the battery voltage during the discharge process, as shown in the figure. Figure 5 and 6 shown.

[0074] The experimental results show that as the discharge progresses, the battery voltage shows a gradual downward trend, while the discharge current remains stable under 0.1C constant current control. The core capacity charge increases linearly with the increase of discharge time, reflecting the consistency between the battery's discharge capacity and the actual state of the battery. These waveform data verify the effectiveness of the system in constant current discharge control, capacity measurement accuracy, and battery state monitoring, providing a reliable basis for the accuracy of core capacity testing.

[0075] In order to implement the above embodiments, the present application also proposes an electronic device, comprising: a processor, and a memory communicatively connected to the processor; the memory stores computer-executable instructions; the processor executes the computer-executable instructions stored in the memory to implement the method provided by the above embodiments.

[0076] In order to implement the above embodiments, the present application also proposes a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are used to implement the methods provided by the above embodiments.

[0077] In order to implement the above embodiments, the present application also proposes a computer program product, including a computer program, which implements the methods provided by the above embodiments when executed by a processor.

[0078] The collection, storage, use, processing, transmission, provision and disclosure of user personal information involved in this application are in compliance with relevant laws and regulations and do not violate public order and good morals.

[0079] It should be noted that personal information from users should be collected for legitimate and reasonable purposes and should not be shared or sold outside of these legitimate uses. In addition, such collection / sharing should be carried out after receiving the user's informed consent, including but not limited to notifying the user to read the user agreement / user notice and sign the agreement / authorization including authorization of relevant user information before the user uses the function. In addition, any necessary steps should be taken to protect and safeguard access to such personal information data and ensure that others who have access to personal information data comply with its privacy policy and procedures.

[0080] The present application is expected to provide an implementation scheme for users to selectively block the use or access of personal information data. That is, the present disclosure is expected to provide hardware and / or software to prevent or block access to such personal information data. Once the personal information data is no longer needed, the risk can be minimized by limiting data collection and deleting the data. In addition, when applicable, such personal information is de-identified to protect the privacy of the user.

[0081] In the description of the aforementioned embodiments, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they contradict each other.

[0082] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0083] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0084] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways if necessary, and then stored in a computer memory.

[0085] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0086] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0087] In addition, each functional unit in each embodiment of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0088] The storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, etc. Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present application. A person of ordinary skill in the art may change, modify, replace and modify the above embodiments within the scope of the present application.

[0089] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps recorded in this application can be executed in parallel, sequentially or in different orders, as long as the expected results of the technical solution of this application can be achieved, and this document is not limited here.

[0090] The above specific implementations do not constitute a limitation on the protection scope of this application. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of this application should be included in the protection scope of this application.

Claims

1. A bidirectional parallel battery core capacity system, characterized in that: include: The station control system is used to connect various DC monitoring systems through Ethernet network to achieve overall monitoring of the system; A plurality of DC buses, each of which is connected to a corresponding DC monitoring to provide transmission and distribution of DC power; AC busbar, connected to the grid side, used to supply power to AC type electrical equipment or converters; A plurality of battery packs, respectively connected to the corresponding DC busbars, for storing and providing DC power, wherein the battery pack comprises a plurality of battery modules connected in parallel, each battery module comprises a pair of managed batteries and a charge and discharge control circuit for managing the charge and discharge state of the battery; A plurality of battery optimizers are connected to the corresponding battery packs to realize online repair, real-time data monitoring, charge and discharge balance and fault protection of single cells to ensure the overall efficiency and service life of the system; A plurality of bidirectional charge and discharge modules are connected between the AC bus, the corresponding battery pack and the DC bus, and are used to convert AC power into DC power and provide power support for the DC bus, or to charge and discharge the battery pack when necessary to realize online capacity verification of the battery and provide power support for the AC load.

2. The system according to claim 1, characterized in that In the battery pack, the battery modules connected in parallel are connected to the input and output circuits of other battery modules of each corresponding branch through a DC / DC circuit or a bidirectional AC / DC circuit. There is no direct connection between the batteries in different branches. The structure between the batteries is indirect parallel connection, and there will be no loop current phenomenon. In the battery modules connected in parallel, the charge and discharge control circuit replaces the inspection device of the traditional battery pack, and enables the battery and the charge and discharge control circuit to be managed in pairs, which is convenient for switching on and off of a single battery.

3. The system according to claim 2, characterized in that include: When the voltage sources of the battery modules connected in parallel operate normally, the circuit supplies power to the load with AC power; When the AC power fails, the batteries in the battery modules connected in parallel convert the voltage through the boost DC / DC conversion module to supply power to the load instead of the AC power circuit; When the AC power resumes normal operation, the battery in the battery module is charged through the Buck circuit and a voltage source is provided to the load. The battery is connected to the load DC bus through the Boost circuit to supply power to the bus at any time.

4. The system according to claim 1, characterized in that The battery optimizer is specifically used for: Balancing the charge and discharge states of each battery module in the battery pack, and dynamically adjusting the charge and discharge current of each battery module to ensure that the charge states of each battery module are balanced; Dynamically adjust the charge and discharge parameters of each battery under different usage conditions, give priority to using batteries in better condition according to the health status of each battery, and reduce excessive use of deteriorated batteries; The temperature, voltage and current of each battery module are monitored. When an abnormal situation is detected, the abnormal battery module is automatically controlled to exit the parallel system and perform independent pulse repair and trickle charging.

5. A bidirectional parallel battery capacity evaluation method, applied to the bidirectional parallel battery capacity evaluation system according to any one of claims 1 to 4, characterized in that: The following steps are involved: Determine the nominal capacity of the battery that needs to be verified and measure the current voltage of the battery; Control the bidirectional charge and discharge module to adjust the output power so that the corresponding battery discharges at a constant current of 0.1C; Detecting the current and voltage parameters of the battery, and recording the discharged capacity and continuous discharge time of the battery; Using Lagrange interpolation method to determine whether the battery voltage meets the discharge termination voltage, if so, exit the discharge capacity verification process, otherwise, execute the next step; Determine whether the capacity discharged by the battery reaches the target value, if so, exit the discharge capacity verification process, otherwise, execute the next step; Determine whether the continuous discharge time of the battery reaches the discharge protection time or whether the temperature is over, if so, exit the discharge capacity verification process, otherwise, adjust the discharge current target value of the battery, and control the bidirectional charge and discharge module to adjust the output power according to the discharge current target value, so that the corresponding battery performs constant current discharge at the discharge current target value, and re-executes the discharge process; When the battery exits the discharge capacity verification process, the bidirectional charge and discharge module is controlled to adjust the output power so that the corresponding battery is charged with a constant current at a charging current target value, and the charging state of the battery is detected and recorded until the capacity verification is completed.

6. The method according to claim 5, characterized in that When the battery is discharged to its nuclear capacity, the method includes: The electric energy released by the battery is controlled to first flow to the load connected in parallel therewith, directly supplying power to the load equipment. When the load demand is small and there is surplus electric energy, the remaining electric energy is fed back to the AC power grid through the bidirectional charging and discharging module.

7. The method according to claim 5, characterized in that The method of using the Lagrange interpolation method to determine whether the battery voltage meets the discharge termination voltage includes: S1. When the battery is discharged to its nuclear capacity, the terminal voltage of the battery is recorded once every hour; S2. If the capacity decay rate of the entire battery group does not meet the preset requirements and the total discharge time is not less than four hours, the cubic Lagrange interpolation polynomial of the battery terminal voltage is constructed using the last four recorded data; if the capacity decay rate of the entire battery group does not meet the requirements and the total discharge time is less than four hours, the Lagrange interpolation polynomial of the corresponding order of the battery terminal voltage is constructed using all the data; S3, estimating the terminal voltage of the battery under the specified total discharge time according to the constructed Lagrange interpolation polynomial, if the terminal voltage estimate is greater than the last actual terminal voltage record value, constructing a Lagrange interpolation using the last two actual terminal voltage record values, and correcting the terminal voltage estimate according to the Lagrange interpolation to obtain a voltage correction value; S4. Compare and judge the voltage correction value with the discharge termination voltage.

8. The method according to claim 7, characterized in that Also includes: If the terminal voltage estimation value is not greater than the last actual terminal voltage record value, return to step S2.

9. An electronic device, characterized in that: include: A processor, and a memory communicatively connected to the processor; The memory stores computer-executable instructions; The processor executes the computer-executable instructions stored in the memory to implement the method according to any one of claims 5 to 8.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions, which are used to implement the method according to any one of claims 5 to 8 when executed by a processor.

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