Energy storage system for multi-framework echelon utilization of whole pack of retired batteries

Abstract

The invention relates to an energy storage system for multi-framework echelon utilization of a whole decommissioned battery pack, and the system comprises a plurality of decommissioned battery packs which are used for collecting the state data of batteries; the cloud server is used for storing historical data of the power grid; the master control subsystem is used for acquiring real-time data of a power grid, predicting charging and discharging power and charging and discharging quantity in the next time period through the real-time data and historical data of the power grid, estimating the SOC state and the SOH state of the battery based on the state data, and calculating the SOC state and the SOH state of the battery according to the charging and discharging power and the charging and discharging quantity in the next time period in combination with the SOC state and the SOH state of the battery. The optimal charging and discharging power and the optimal charging and discharging quantity are decided; and the PCS subsystem is used for carrying out alternating current and direct current bidirectional conversion on electric energy between the plurality of retired battery packs and the power grid according to the optimal charging and discharging power and the optimal charging and discharging quantity, so that the active power and the reactive power of the power grid are adjusted, and peak load shifting is realized. The safety performance and the economic benefit of the energy storage system are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage systems, and in particular to a multi-architecture energy storage system for cascading utilization of whole packages of retired batteries. Background Art

[0002] With the rapid development of new energy vehicles, a large number of power batteries will enter the retirement period in 2030. The industrial and commercial energy storage system made of retired batteries is an effective way to promote the cascade utilization of retired power batteries, among which the design of energy storage system is its core technology. At the same time, a small part of the energy storage field is based on the battery packs of retired cascade batteries, and most of them are new batteries and battery packs after screening and reorganization, which increases the investment cost of energy storage. The technology of screening retired battery modules is difficult and the reorganization cost is high. In addition, due to the diversity and inconsistency of batteries, the existing energy storage system requires personnel to regularly check the battery status and deal with unexpected situations in a timely manner. Finally, the traditional energy storage system does not involve the internal resistance detection module, and the estimation of the battery's SOC and SOH is less accurate.

[0003] Therefore, in order to improve the safety and economy of second-life power batteries, it is necessary to design an efficient and reasonable energy storage system structure. Summary of the invention

[0004] In order to solve the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a multi-architecture energy storage system for cascading utilization of a whole pack of retired batteries. The multi-architecture design reduces the manufacturing cost and maintenance cost. The fusion algorithm is used to estimate the battery status with high precision, realize accurate charge and discharge regulation, and reduce peak loads, thereby improving the safety performance and economic benefits of the energy storage system.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] A multi-architecture energy storage system for cascading utilization of a whole pack of retired batteries, comprising:

[0007] Several retired battery packs, used to collect battery status data; the status data includes: voltage, current, temperature and internal resistance;

[0008] Cloud servers for storing historical data of the power grid;

[0009] The main control subsystem is used to obtain real-time data of the power grid, predict the charge and discharge power and charge and discharge amount in the next time period through the real-time data and historical data of the power grid, estimate the SOC state and SOH state of the battery based on the state data, and decide the optimal charge and discharge power and charge and discharge amount of the battery according to the charge and discharge power and charge and discharge amount in the next time period and the SOC state and SOH state of the battery;

[0010] The PCS subsystem is used to perform AC / DC bidirectional conversion of the electric energy between the retired battery packs and the power grid according to the optimal charge and discharge power and charge and discharge amount, thereby adjusting the active power and reactive power of the power grid and shaving peaks and filling valleys.

[0011] Optionally, the retired battery pack includes:

[0012] Voltage acquisition module, used to collect the voltage of the battery;

[0013] Current acquisition module, used to collect battery current;

[0014] Temperature acquisition module, used to collect the temperature of the battery;

[0015] Internal resistance acquisition module, used to collect the internal resistance of the battery;

[0016] AD converter module, used to convert the voltage, current, temperature and internal resistance of the battery into corresponding digital signals;

[0017] The CAN communication module is used to transmit the corresponding digital signal to the main control subsystem and transmit the decision information of the main control subsystem, that is, the optimal charging and discharging power and charging and discharging amount.

[0018] Optionally, the retired battery pack further includes:

[0019] A balancing module is used to determine the active balancing object according to the decision information, that is, to set a voltage difference threshold, to judge the voltage difference between the battery packs according to the voltage difference threshold, and to transfer the energy in the battery with a higher voltage in the voltage difference comparison to the battery with a lower voltage in the voltage difference comparison, so as to achieve voltage balancing of each single battery in the battery pack;

[0020] A charge and discharge module, used to adjust the consistency of the battery based on the active balancing object, and to pre-charge the battery before charging to protect the charge and discharge circuit;

[0021] The graded alarm module is used to set corresponding target thresholds for the voltage, current, temperature and internal resistance of the battery, and to perform graded alarms on the battery according to the corresponding target thresholds.

[0022] Optionally, the main control subsystem includes:

[0023] 4G communication module, used for data transmission between the cloud server and the power grid, and obtaining real-time data and historical data of the power grid; the power grid data includes: voltage, current, frequency and phase data of the power grid;

[0024] An information storage module, used for storing historical data of the power grid;

[0025] The EMS microprocessor is used to predict the charging and discharging power and charging and discharging amount in the next time period based on the historical data of the power grid stored in the information storage module and the real-time data of the power grid;

[0026] The SOC and SOH joint estimation module is used to estimate the SOC using the Kalman filter algorithm. The process includes the following four steps: performing a priori estimation of the time update of the state data, obtaining the estimated system state parameters, updating the a posteriori estimation after completing the estimation, and further shifting the time to the next moment to obtain the latest estimation value; since the battery capacity is related to the SOC parameter, the SOH is calibrated by the SOC to determine the SOC state and SOH state of the battery;

[0027] The data analysis module is used to determine the optimal charge and discharge power and charge and discharge amount according to the charge and discharge power and charge and discharge amount in the next time period in combination with the SOC state and SOH state of the battery.

[0028] Optionally, the main control subsystem further includes:

[0029] Heating and cooling modules are used to ensure that related modules and electrical components operate within a suitable temperature range;

[0030] Lighting module, used to check the status of the energy storage system and repair and replace damaged modules according to the LED light group;

[0031] The fire-fighting module is used to extinguish the ignited battery in the event of a fire caused by thermal runaway.

[0032] Optionally, the fire protection module includes: a composite fire detector and a perfluorohexanone nozzle.

[0033] Optionally, the system further comprises:

[0034] The host computer subsystem is used to check the energy storage system status of the main control subsystem under special circumstances.

[0035] The beneficial effects of the present invention are:

[0036] The present invention realizes the cascade utilization of the entire package of retired batteries through the design of a multi-architecture energy storage system, without the need to screen and reorganize the retired batteries, thus solving the technical difficulties and cost issues of battery screening and reorganization.

[0037] In order to reduce the maintenance difficulty of the energy storage system, the present invention improves the consistency between battery packs through an active balancing system; realizes efficient heat dissipation of the battery pack through a reasonable temperature design module to ensure that the battery works within a suitable range; realizes online high-precision battery performance estimation and parameter modification through communication between the main control system and the cloud server, and is equipped with a fire protection system to deal with unexpected situations.

[0038] The present invention adds an internal resistance detection module, utilizes the internal resistance in conjunction with the SOC and SOH estimation algorithms to improve the accuracy of the algorithms, and simultaneously communicates with the cloud server to achieve high-precision online performance calculations.

[0039] In summary, the present invention can improve the economy and feasibility of retired battery energy storage utilization and provide a more comprehensive solution for system architecture design in the energy storage field. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0041] Figure 1 A block diagram of an energy storage system for cascading utilization of a whole pack of retired batteries using a multi-architecture according to an embodiment of the present invention;

[0042] Figure 2 is a system block diagram of a main control system according to an embodiment of the present invention;

[0043] Figure 3 A block diagram of a retired battery pack system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0046] like Figure 1As shown, this embodiment discloses a multi-architecture energy storage system for cascading utilization of a whole pack of retired batteries, including: a number of retired battery packs, used to collect battery status data; the status data includes: voltage, current, temperature and internal resistance; a cloud server, used to store historical data of the power grid; a main control subsystem, used to obtain real-time data of the power grid, and predict the charge and discharge power and charge and discharge amount in the next time period through the real-time data and historical data of the power grid, and estimate the SOC state and SOH state of the battery based on the status data, and decide the optimal charge and discharge power and charge and discharge amount according to the charge and discharge power and charge and discharge amount in the next time period in combination with the SOC state and SOH state of the battery; a PCS subsystem, used to perform AC / DC bidirectional conversion of electric energy between a number of retired battery packs and the power grid according to the optimal charge and discharge power and charge and discharge amount, thereby adjusting the active power and reactive power of the power grid and shaving the peak and filling the valley.

[0047] Specifically:

[0048] like Figure 1 This embodiment discloses a multi-architecture energy storage system for cascading utilization of a whole pack of retired batteries, including: a retired battery pack, a main control system, a cloud server, a power grid, a PCS (energy storage converter) module and a host computer module.

[0049] like Figure 2 ,The main control system includes: EMS microprocessor, communication module, high-precision SOC, SOH joint estimation module, data analysis module, information storage module, heating / cooling module, lighting module and fire fighting module.

[0050] like Figure 3 The retired battery pack includes: voltage acquisition module, current acquisition module, temperature acquisition module, internal resistance acquisition module, graded alarm module, CAN communication module, balancing module, and charging and discharging module. The voltage acquisition module, current acquisition module, temperature acquisition module, and internal resistance acquisition module are all equipped with AD conversion modules and CAN communication interfaces.

[0051] The energy storage system architecture includes: the retired battery pack is connected to the main control system via CAN communication, the main control system is connected to the host computer via CAN communication or Bluetooth communication, and the main control system and the cloud server transmit data bidirectionally via 4G communication.

[0052] The energy storage system formulates the optimal charging and discharging strategy for the energy storage system based on the real-time battery status and grid demand, using historical data and high-precision SOC and SOH joint algorithms to achieve peak shaving and valley filling.

[0053] Furthermore, the retired battery pack includes: a voltage acquisition module for acquiring the voltage of the battery; a current acquisition module for acquiring the current of the battery; a temperature acquisition module for acquiring the temperature of the battery; an internal resistance acquisition module for acquiring the internal resistance of the battery; an AD converter module for converting the voltage, current, temperature and internal resistance of the battery into corresponding digital signals; a CAN communication module for transmitting the corresponding digital signals to the main control subsystem and transmitting the decision information of the main control subsystem, namely the optimal charge and discharge power and charge and discharge amount.

[0054] Specifically: the retired battery includes a voltage acquisition module, a current acquisition module, a temperature acquisition module, an internal resistance acquisition module, a graded alarm module, a CAN communication module, a balancing module, and a charge and discharge module. The voltage acquisition module, the current acquisition module, the temperature acquisition module, and the internal resistance acquisition module are all provided with an AD conversion module and a CAN communication interface. The voltage acquisition module, the current acquisition module, the temperature acquisition module, and the internal resistance acquisition module convert the collected battery information into corresponding digital signals through an AD converter and send the signals to the CAN communication module, the CAN communication module sends signals to the graded alarm module, and the CAN communication module and the communication module of the main control system transmit signals in both directions.

[0055] CAN communication module has a fast transmission rate, can quickly collect and transmit a large amount of data, maintain the real-time nature of data updates, and has strong data stability. It has data self-checking and data recovery functions. If an error is detected, it will force the current data transmission to end. The CAN bus also has an error recovery function. The module that forcefully ends the transmission will repeatedly resend the message until it is successfully sent.

[0056] Furthermore, the retired battery pack also includes: a balancing module, which is used to determine the active balancing object according to the decision information, that is, to set a voltage difference threshold, judge the voltage difference between the battery packs according to the voltage difference threshold, and transfer the energy in the battery with a higher voltage in the pressure difference comparison to the battery with a lower voltage in the pressure difference comparison, so as to achieve voltage balancing of each single cell in the battery pack; a charging and discharging module, which is used to adjust the consistency of the battery based on the active balancing object, and pre-charge the battery before charging to protect the charging and discharging circuit; a graded alarm module, which is used to set corresponding target thresholds for the voltage, current, temperature and internal resistance of the battery, and perform graded alarms on the battery according to the corresponding target thresholds.

[0057] Specifically: the balancing module determines the active balancing object according to the signal of the main control system, realizes the consistency of the battery pack through the charging and discharging module, and prolongs the battery life (such as single cell overvoltage protection (level 1) voltage 3.62V, delay 3s, only alarm but no protection, recovery when the highest single cell voltage is less than 3.35V or the discharge current is greater than 0.8A, single cell overvoltage protection (level 2) voltage 3.65V, delay 10s, charging MOS: OFF, discharging MOS: ON, recovery when the highest single cell voltage is less than 3.35V or the discharge current is greater than 0.8A). The charging and discharging module also includes a pre-charging function to protect the charging and discharging circuit.

[0058] Furthermore, the main control subsystem includes: a 4G communication module for transmitting data with a cloud server and a power grid to obtain real-time and historical data of the power grid; the power grid data includes: data such as voltage, current, frequency and phase of the power grid; an information storage module for storing historical data of the power grid; an EMS microprocessor for predicting the charge and discharge power and charge and discharge amount in the next time period based on the historical data of the power grid stored in the information storage module in combination with the real-time data of the power grid; a SOC and SOH joint estimation module for first estimating the SOC using a Kalman filter algorithm, and the process includes the following four steps: performing a priori estimation of the time update of the state data, obtaining the estimated system state parameters, updating the a posteriori estimation after completing the estimation, and further shifting the time to the next moment to obtain the latest estimated value; since the battery capacity is related to the SOC parameter, the SOH is calibrated by the SOC to determine the SOC state and SOH state of the battery; a data analysis module for deciding the optimal charge and discharge power and charge and discharge amount based on the charge and discharge power and charge and discharge amount in the next time period in combination with the SOC state and SOH state of the battery.

[0059] Furthermore, the main control subsystem also includes: a heating and cooling module, which is used to ensure that related modules and electrical components operate within a suitable temperature range; a lighting module, which is used to check the status of the energy storage system according to the LED light group and repair and replace damaged modules; a fire protection module, which is used to extinguish the ignited battery when a fire is caused by thermal runaway.

[0060] Furthermore, the fire fighting module includes: a composite fire detector and a perfluorohexanone nozzle.

[0061] Specifically:

[0062] The main control system includes EMS microprocessor, communication module, high-precision SOC, SOH joint estimation module, data analysis module, information storage module, heating / cooling module, lighting module and fire protection module.

[0063] The EMS microprocessor transmits data with the retired battery pack through CAN communication, and transmits data bidirectionally with the cloud server through 4G communication. The EMS microprocessor predicts the charge and discharge power and charge and discharge amount of the next time period through the historical data in the information storage module, 4G communication and real-time data transmission of the power grid. The EMS microprocessor estimates the SOC and SOH status of the battery with high precision through the high-precision SOC and SOH joint estimation module and the collected data of the retired battery pack, and judges the safety and consistency of the battery pack. At the same time, combined with the data analysis module, the optimal charge and discharge power and charge and discharge amount of the energy storage system are determined. The heating method of the heating / cooling module includes but is not limited to electric heating and fan heating, and the cooling method of the heating / cooling module includes but is not limited to air cooling, liquid cooling and phase change cooling. The heating / cooling module ensures that the relevant modules and electrical components work within the appropriate temperature range to ensure the stable operation of the energy storage system. The lighting module includes an LED light group, which is convenient for maintenance personnel to check the status of the energy storage system, repair and replace damaged modules, and avoid safety risks. The fire protection module includes a composite fire detector and a perfluorohexanone nozzle to avoid fires caused by thermal runaway.

[0064] The prediction of the charging and discharging power and amount in the next time period includes: the power of the demand counted in the same time period in previous years, the power of the demand counted in the same time period in the past month, and the power of the demand counted in the same time period in the past three days. The theoretical power demand is obtained through the weighted coefficient. The specific number of data parameters depends on the computing power. The charging and discharging amount is the product of power and time.

[0065] Estimating the battery's SOC and SOH states includes: Kalman filter algorithm, including algorithm initialization, obtaining the initial value of the state observer, completing the prior estimation of time update, obtaining the estimated system state parameters, completing the measurement and updating the a posteriori estimation, and finally moving the time to the next moment to obtain the latest estimated value. In the joint estimation, SOC and SOH are function parameters of each other.

[0066] The cloud server has two-way data transmission with the power grid and the main control system, and can update the battery status data online. It uses the historical data stored in the cloud server and adopts a fusion algorithm to estimate the current SOC and SOH of the battery. According to the needs of the power grid, the optimal charging and discharging strategy of the energy storage system is determined.

[0067] The PCS module mainly includes a DC / AC (alternating current / direct current) bidirectional converter, a control unit and other auxiliary units. The DC / AC bidirectional converter realizes the AC / DC bidirectional conversion of electric energy, adjusts the active power and reactive power of the power grid, and reduces peak loads and fills valleys.

[0068] Furthermore, the system also includes: a host computer subsystem, which is used to check the energy storage system status of the main control subsystem under special circumstances.

[0069] Specifically:

[0070] The host computer module is connected to the main control system through a CAN communication module or a Bluetooth module. Under special circumstances, it is convenient for on-site maintenance personnel to check the status of the energy storage system on site.

[0071] This embodiment discloses a multi-architecture energy storage system for cascading utilization of a whole pack of retired batteries, including:

[0072] The main control system includes EMS microprocessor, communication module, high-precision SOC, SOH joint estimation module, data analysis module, information storage module, heating / cooling module, lighting module and fire protection module.

[0073] The EMS microprocessor transmits data with the retired battery pack through CAN communication to obtain the battery voltage, current, temperature and internal resistance, and uses the high-precision SOC and SOH joint estimation module to estimate the battery SOC and SOH status. At the same time, the charging and discharging power and charging and discharging amount in the next time period are predicted through the historical data in the information storage module and the real-time data of the power grid. Combined with the data analysis module, the optimal charging and discharging power and charging and discharging amount of the energy storage system are determined.

[0074] Finally, the PCS module completes the AC / DC bidirectional conversion of electric energy, realizes the regulation of active power and reactive power of the power grid, and reduces peak loads and fills valleys.

[0075] The implementation process also includes a heating / cooling module, which ensures that related modules and electrical components work within a suitable temperature range to ensure the stable operation of the energy storage system. The lighting module includes an LED light group, which is convenient for maintenance personnel to check the status of the energy storage system, repair and replace damaged modules, and avoid safety risks. The fire protection module includes a composite fire detector and a perfluorohexanone nozzle to avoid fires caused by thermal runaway. The upper computer module is connected to the main control system through a CAN communication module or a Bluetooth module. Under special circumstances, it is convenient for on-site maintenance personnel to check the status of the energy storage system on site.

[0076] The embodiments described above are only descriptions of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A multi-architecture energy storage system for cascading utilization of a whole pack of retired batteries, characterized in that: include: Several retired battery packs for collecting battery status data; The state data includes: voltage, current, temperature and internal resistance; Cloud servers for storing historical data of the power grid; The main control subsystem is used to obtain real-time data of the power grid, predict the charge and discharge power and charge and discharge amount in the next time period through the real-time data and historical data of the power grid, estimate the SOC state and SOH state of the battery based on the state data, and decide the optimal charge and discharge power and charge and discharge amount of the battery according to the charge and discharge power and charge and discharge amount in the next time period and the SOC state and SOH state of the battery; The PCS subsystem is used to perform AC / DC bidirectional conversion of the electric energy between the retired battery packs and the power grid according to the optimal charge and discharge power and charge and discharge amount, thereby adjusting the active power and reactive power of the power grid and shaving peaks and filling valleys.

2. The multi-architecture energy storage system for cascading utilization of a whole pack of retired batteries according to claim 1 is characterized in that: The retired battery pack comprises: Voltage acquisition module, used to collect the voltage of the battery; Current acquisition module, used to collect battery current; Temperature acquisition module, used to collect the temperature of the battery; Internal resistance acquisition module, used to collect the internal resistance of the battery; AD converter module, used to convert the voltage, current, temperature and internal resistance of the battery into corresponding digital signals; The CAN communication module is used to transmit the corresponding digital signal to the main control subsystem and transmit the decision information of the main control subsystem, that is, the optimal charging and discharging power and charging and discharging amount.

3. The multi-architecture energy storage system for cascading utilization of a whole pack of retired batteries according to claim 2 is characterized in that: The retired battery pack also includes: A balancing module is used to determine the active balancing object according to the decision information, that is, to set a voltage difference threshold, to judge the voltage difference between the battery packs according to the voltage difference threshold, and to transfer the energy in the battery with a higher voltage in the voltage difference comparison to the battery with a lower voltage in the voltage difference comparison, so as to achieve voltage balancing of each single battery in the battery pack; A charge and discharge module, used to adjust the consistency of the battery based on the active balancing object, and to pre-charge the battery before charging to protect the charge and discharge circuit; The graded alarm module is used to set corresponding target thresholds for the voltage, current, temperature and internal resistance of the battery, and to perform graded alarms on the battery according to the corresponding target thresholds.

4. The multi-structure energy storage system for cascading utilization of a whole pack of retired batteries according to claim 1 is characterized in that: The main control subsystem includes: 4G communication module, used for data transmission between the cloud server and the power grid, and obtaining real-time data and historical data of the power grid; the power grid data includes: voltage, current, frequency and phase data of the power grid; An information storage module, used for storing historical data of the power grid; The EMS microprocessor is used to predict the charging and discharging power and charging and discharging amount in the next time period based on the historical data of the power grid stored in the information storage module and the real-time data of the power grid; The SOC and SOH joint estimation module is used to estimate the SOC using the Kalman filter algorithm. The process includes the following four steps: performing a priori estimation of the time update of the state data, obtaining the estimated system state parameters, updating the a posteriori estimation after completing the estimation, and further shifting the time to the next moment to obtain the latest estimation value; since the battery capacity is related to the SOC parameter, the SOH is calibrated by the SOC to determine the SOC state and SOH state of the battery; The data analysis module is used to determine the optimal charge and discharge power and charge and discharge amount according to the charge and discharge power and charge and discharge amount in the next time period in combination with the SOC state and SOH state of the battery.

5. The multi-frame energy storage system for cascading utilization of a whole pack of retired batteries according to claim 4 is characterized in that: The main control subsystem also includes: Heating and cooling modules are used to ensure that related modules and electrical components operate within a suitable temperature range; Lighting module, used to check the status of the energy storage system and repair and replace damaged modules according to the LED light group; The fire-fighting module is used to extinguish the ignited battery in the event of a fire caused by thermal runaway.

6. The multi-structure energy storage system for cascading utilization of a whole pack of retired batteries according to claim 5 is characterized in that: The fire fighting module comprises: a composite fire detector and a perfluorohexanone nozzle.

7. The multi-frame energy storage system for cascading utilization of a whole pack of retired batteries according to claim 1 is characterized in that: The system also includes: The host computer subsystem is used to check the energy storage system status of the main control subsystem under special circumstances.

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