A modular and reconfigurable supercapacitor energy storage management device

Abstract

The present invention provides a modular and reconfigurable supercapacitor energy storage management device. A supercapacitor module composed of a supercapacitor, an equalization management system BMS, and a bidirectional DC / DC converter is controlled by a switch control unit to alternately perform charge and discharge cycles and self-recovery for each supercapacitor module. The equalization management system BMS maintains voltage balance when the change in the capacitance value of the supercapacitor is different. The bidirectional DC / DC converter realizes current sharing control when the state of the supercapacitor branch switches. The communication unit can transmit state information such as system voltage, supercapacitor capacitance value, internal resistance, etc., and control information such as the number of cycles and cut-off voltage, and perform human-computer interaction through a computer. The capacity and internal resistance monitoring unit combined with the alarm unit can issue an alarm after detecting an abnormality. The above settings effectively extend the service life and usage efficiency of the supercapacitor, ensure the safety of the energy storage unit, and additionally provide a charge and discharge current control unit and a temperature acquisition unit to increase the control variables and further extend the service life and usage efficiency of the supercapacitor.

Description

Technical Field

[0001] The present invention relates to the field of power electronics technology, and particularly to a modular reconfigurable supercapacitor energy storage management device. Background Art

[0002] A supercapacitor is a new type of energy storage element between traditional capacitors and chemical batteries. Compared with conventional energy storage devices, it has advantages such as high charge and discharge efficiency and large energy density. The working environment of supercapacitors is usually relatively harsh, so the actual service life is generally lower than expected. Moreover, supercapacitors decay with each use, and the increase in the number of cycles is often accompanied by performance decay and increased aging. Specifically, in terms of performance parameters, it is manifested as an increase in internal resistance and a decrease in capacitance value. In addition, the rated voltage of a single supercapacitor is relatively low, and generally, supercapacitor modules need to be formed by series and parallel connections. At the same time, due to production process differences, the capacitances of supercapacitors cannot be exactly the same, so the voltage imbalance problem caused will also seriously affect the service life of supercapacitors.

[0003] Regarding the service life problem of supercapacitors, there are two existing mainstream solutions: one is to improve the working environment. Existing research shows that the life of supercapacitors is greatly affected by temperature, voltage, and current. By adjusting parameters such as system temperature, cut-off voltage, charge and discharge current, etc., the service life can be effectively extended; the other is to add compensating supercapacitors and a voltage balancing system, and achieve voltage equalization control through a balanced management system (abbreviated as BMS). After detecting abnormalities in the capacitance value and internal resistance of the supercapacitor, the compensating supercapacitor is put into use to maintain the normal operation of the system. This method will also lead to a decrease in the utilization rate of supercapacitors.

[0004] The above solutions do not take into account the self-recovery effect of supercapacitors and cannot solve the problem of capacitance value decline under high-frequency charge and discharge cycles during the use of supercapacitors. Summary of the Invention

[0005] The present invention provides a modular reconfigurable supercapacitor energy storage management device, which combines traditional solutions and takes into account the self-recovery effect of supercapacitors. The supercapacitors are combined into supercapacitor modules, and by controlling the connection and disconnection of each module, each supercapacitor module is switched between the charge and discharge cycle and the static self-recovery states, thereby effectively increasing the service life and use efficiency of the supercapacitors.

[0006] The technical solution to achieve the object of the present invention is: a modular reconfigurable supercapacitor energy storage management device, including a supercapacitor energy storage unit, a switch control unit, a voltage regulation unit, a capacitance and internal resistance monitoring unit, an alarm unit, a communication unit, a current sharing control unit, and a computer;

[0007] The supercapacitor energy storage unit includes multiple supercapacitor modules, each supercapacitor module is connected in series in turn, the input end of the frontmost supercapacitor module is connected to the DC bus, each supercapacitor module includes multiple supercapacitor branches, both ends of each supercapacitor branch are connected in parallel, a bidirectional DC / DC converter, multiple supercapacitors, an equalization management system BMS connected to each supercapacitor, and a branch switch are connected in turn on each supercapacitor branch. The output end of each supercapacitor module is connected to the input end of the first module switch, the input end of each supercapacitor module is connected to the input end of the second module switch, and the output end of the second module switch is connected to the output end of the first module switch;

[0008] The switch control unit is used to control the branch switch, the first module switch and the second module switch, so that the supercapacitor branches of each supercapacitor module alternately perform charge-discharge cycles and self-recovery;

[0009] The voltage regulation unit is used to regulate the cut-off voltage of each supercapacitor charge-discharge cycle. Different voltage conditions can change the supercapacitor self-recovery effect, and the system service life can be extended by reasonably setting the cut-off voltage;

[0010] The capacity and internal resistance monitoring unit is used to monitor the capacity and internal resistance of each supercapacitor module and single supercapacitor. When the monitored capacity is too low or the internal resistance is too high, the charge-discharge cycle is ended;

[0011] The alarm unit is used to issue an alarm when a system abnormality is detected;

[0012] The communication unit is used to collect system status information in real time and transmit control instructions;

[0013] The inter-module current sharing control unit is combined with the bidirectional DC / DC converter in each supercapacitor module to eliminate the circulating current between the series-connected supercapacitor modules;

[0014] The computer is used for human-computer interaction with each unit of the system.

[0015] Optionally, the system further includes a charge-discharge current control unit and a temperature acquisition unit

[0016] The charge-discharge current control unit is used to adjust the charge-discharge rate of each supercapacitor module during cycling, and the rate is reasonably set according to the cycling required time and load demand to extend the system service life;

[0017] The temperature acquisition unit is used to monitor the temperature of each module of the system in real time, and when it exceeds or is lower than the set threshold, an alarm is issued through the alarm unit.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] Compared with the traditional solution, the self - recovery effect of the supercapacitor is considered. Multiple supercapacitor branches composed of supercapacitors are connected in parallel and combined with the balanced management system BMS and the bidirectional DC / DC converter to form an energy storage unit. The switch control unit controls the switching of the charging and discharging cycles and the self - recovery of each supercapacitor module in turn. The balanced management system BMS can maintain voltage balance when the capacitance change of the supercapacitor is different. The bidirectional DC / DC converter can achieve current sharing control when the state of the supercapacitor branch changes. The communication unit can transmit state information such as system voltage, supercapacitor capacitance, internal resistance, and control information such as cycle number and cut - off voltage, and perform human - machine interaction through a computer. The capacity and internal resistance monitoring unit combined with the alarm unit can issue an alarm after detecting an abnormality, enabling the operator to take corresponding measures in time. The above settings effectively extend the service life of the supercapacitor and improve its usage efficiency, and also ensure the safety of the energy storage unit. The temperature and current variable control unit is added to further extend the service life of the supercapacitor. Brief Description of the Drawings

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0021] Figure 1 It is the effect diagram of the capacity attenuation and self - recovery of the supercapacitor under the condition of 2.9V;

[0022] Figure 2 It is the effect diagram of the increase in internal resistance and self - recovery of the supercapacitor under the condition of 2.9V;

[0023] Figure 3 It is the effect diagram of the capacity attenuation and self - recovery of the supercapacitor under the condition of 2.4V;

[0024] Figure 4 It is the effect diagram of the increase in internal resistance and self - recovery of the supercapacitor under the condition of 2.4V;

[0025] Figure 5 It is the schematic diagram of the architecture of a modular reconfigurable supercapacitor energy storage management device provided by the embodiment of the present disclosure;

[0026] Figure 6 It is the operation flow chart of the modular reconfigurable supercapacitor energy storage management device. Detailed Embodiments

[0027] Embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. On the contrary, these embodiments are provided to more thoroughly and completely understand the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not used to limit the protection scope of the present invention.

[0028] The technical solutions of the present invention will be described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments.

[0029] The self-recovery effect of the supercapacitor can be verified by the following experiment:

[0030] Set the cut-off voltages of two supercapacitors to 2.9V and 2.4V respectively, and perform 150,000 charge-discharge cycles on the supercapacitors. Perform a short-term static stop every 50,000 cycles. The first static stop time is 1 day, and the second is 8 days.

[0031] As Figure 1 and Figure 2 shown, under the condition of 2.9V, the capacity attenuations of the two supercapacitors in the first 50,000 charge-discharge cycles are 28.27% and 27.11% respectively, and the internal resistances increase by 58.10% and 79.74% respectively. The capacity attenuations in the second 50,000 charge-discharge cycles are 18.96% and 19.72% respectively, and the internal resistances increase by 26.26% and 49.02% respectively. The capacity attenuations in the third 50,000 charge-discharge cycles are 22.16% and 21.83% respectively, and the internal resistances increase by 69.83% and 78.43% respectively. When the static stop time is 1 day, the capacities can be restored by 18.06% and 18.55% respectively, and the internal resistances are reduced by 20.67% and 35.95% respectively. When the static stop time is 8 days, the capacities can be restored by 22.56% and 22.34% respectively, and the internal resistances are reduced by 73.18% and 84.97% respectively.

[0032] As Figure 3 and Figure 4As shown, under the condition of 2.4V, the capacity decays of two supercapacitors in the first 50,000 charge-discharge cycles are 10.00%, 11.38%, and 11.70% respectively, and the internal resistances increase by 11.70%, 25.17%, and 23.81% respectively. The capacity decays in the second 50,000 charge-discharge cycles are 8.30%, 7.67%, and 7.83% respectively, and the capacitance values increase by 30.99%, 24.49%, and 42.86% respectively. The capacity decays in the third 50,000 charge-discharge cycles are 8.25%, 9.10%, and 8.63% respectively, and the internal resistances increase by 29.82%, 44.22%, and 36.05% respectively. When the static time is 1 day, the capacities can be restored by 7.5%, 6.55%, and 6.84% respectively, and the internal resistances are reduced by 23.98%, 38.78%, and 38.78% respectively. When the static time is 8 days, the capacities can be restored by 8.57%, 8.74%, and 7.41% respectively, and the internal resistances are reduced by 37.43%, 27.90, and 45.58% respectively.

[0033] The experimental data show that if the supercapacitor is static for a period of time after a certain number of cycles, its capacitance value and internal resistance will be restored to a certain extent. By using this effect to optimize the system design and combining with the existing methods, the service life of the supercapacitor can be further extended and the utilization rate of the supercapacitor can be improved.

[0034] Figure 5 A modular reconfigurable supercapacitor energy storage management device provided by an embodiment of the present disclosure includes a supercapacitor energy storage unit, a switch control unit, a voltage regulation unit, a capacity and internal resistance monitoring unit, an alarm unit, a communication unit, a current sharing control unit, and a computer;

[0035] The supercapacitor energy storage unit includes n supercapacitor modules, each supercapacitor module is connected in series in turn, the input end of the frontmost supercapacitor module is connected to the DC bus, each supercapacitor module includes a plurality of supercapacitor branches, both ends of each supercapacitor branch are connected in parallel, a bidirectional DC / DC converter, a plurality of supercapacitors, an equalization management system BMS connected to each supercapacitor, and a branch switch are connected in turn on each supercapacitor branch, the output end of each supercapacitor module is connected to the input end of the first module switch, the input end of each supercapacitor module is connected to the input end of the second module switch, and the output end of the second module switch is connected to the output end of the first module switch;

[0036] The switch control unit is used to control the branch switch, the first module switch, and the second module switch to make the supercapacitor branches of each supercapacitor module perform charge-discharge cycles and self-recovery alternately;

[0037] The voltage regulation unit is used to adjust the cut-off voltage of each supercapacitor charge-discharge cycle. Different voltage conditions can change the self-recovery effect of the supercapacitor. By reasonably setting the cut-off voltage, the service life of the system can be extended;

[0038] A capacity and internal resistance monitoring unit is used to monitor the capacity and internal resistance of each supercapacitor module and individual supercapacitor. When the monitored capacity is too low or the internal resistance is too high, the charge-discharge cycle is ended.

[0039] An alarm unit is used to issue an alarm when a system abnormality is detected.

[0040] A communication unit is used to collect and transmit system status information and control instructions in real time.

[0041] An inter-module current sharing control unit is combined with the bidirectional DC / DC converters in each supercapacitor module to eliminate the circulating current between series-connected supercapacitor modules.

[0042] A computer is used for human-computer interaction with each unit of the system.

[0043] A charge-discharge current control unit is used to adjust the charge-discharge rate of each supercapacitor module during cycling, and reasonably set the rate according to the required cycling time and load demand to extend the system service life.

[0044] A temperature acquisition unit is used to monitor the temperature of each module of the system in real time. When the temperature exceeds or is lower than the set threshold, an alarm is issued through the alarm unit.

[0045] The operation process of this system is as follows:

[0046] Reference Figure 6 , before the system runs normally, the system first executes an initialization program. Secondly, the number of cycles and cut-off voltage before self-recovery of each module are set. After completion, the communication unit issues an instruction to the switch control unit, and the system starts to run. Starting from supercapacitor module #1, the first module switch S of supercapacitor module #1 11 is turned on, the second module switch S 12 is turned off, the first module switches S of the remaining supercapacitor modules k1 are disconnected, and the second module switches S k2 are turned on (k = 2, 3,..., n). That is, the supercapacitor module #1 controlled by the switches S 11 , S 12 enters the self-recovery state, and the remaining supercapacitor modules perform charge-discharge cycling. After meeting the set number of cycles, the switch S 11 is turned off, and the switch S 12 is turned on. Supercapacitor module 1# ends self-recovery and performs charge-discharge cycling. At the same time, the switch S 21 is turned on, and the switch S 22After the system is shut down, supercapacitor module 2# ends the charge and discharge cycle and performs self-recovery. After that, each module switches state in turn after meeting the number of charge and discharge cycles. After supercapacitor module #n completes self-recovery, it returns to supercapacitor module 1# and restarts the self-recovery and charge and discharge cycle of each module. While the system is running, the operator can conduct human-computer interaction through a computer combined with a communication unit connected to each unit of the system. The communication unit can collect system status information in real time and transmit computer instructions to adjust the system in a timely manner. Taking into account the difference between the initial capacitance and capacitance change of each capacitor, the voltage balancing control of the supercapacitor is carried out through the balancing management system BMS. The current sharing control unit is combined with the bidirectional DC / DC converter in each supercapacitor module to eliminate the circulating current between the series supercapacitor modules. At the same time, the capacity and internal resistance monitoring unit monitors the capacity and internal resistance of each supercapacitor module and a single supercapacitor. When the capacity is detected to be too low or the internal resistance is too high, the charge and discharge cycle is terminated and an alarm is issued through the alarm unit.

[0047] In addition, a charging and discharging current control unit and a temperature acquisition unit are added to increase the control variables, further effectively extending the service life and utilization efficiency of the supercapacitor.

Claims

1. A modular reconfigurable supercapacitor energy storage management device, characterized in that: It includes a supercapacitor energy storage unit, a switch control unit, a voltage regulation unit, a capacity and internal resistance monitoring unit, an alarm unit, a communication unit, a current sharing control unit and a computer; The supercapacitor energy storage unit includes a plurality of supercapacitor modules, each of which is connected in series in sequence, the input end of the front supercapacitor module is connected to the DC bus, each supercapacitor module includes a plurality of supercapacitor branches, the two ends of each supercapacitor branch are connected in parallel, and each supercapacitor branch is sequentially connected to a bidirectional DC / DC converter, a plurality of supercapacitors, a balancing management system (BMS) connected to each supercapacitor, and a branch switch, the output end of each supercapacitor module is connected to the input end of the first module switch, the input end of each supercapacitor module is connected to the input end of the second module switch, and the output end of the second module switch is connected to the output end of the first module switch; The switch control unit is used to control the branch switch, the first module switch and the second module switch so that the supercapacitor branches of each supercapacitor module perform charge and discharge cycles and self-recovery in turn; The voltage regulating unit is used to adjust the cut-off voltage of each supercapacitor charge and discharge cycle. Different voltage conditions can change the self-recovery effect of the supercapacitor. By reasonably setting the cut-off voltage, the service life of the system can be extended. The capacity and internal resistance monitoring unit is used to monitor the capacity and internal resistance of each supercapacitor module and a single supercapacitor, and terminate the charge and discharge cycle when the capacity is too low or the internal resistance is too high; The alarm unit is used to issue an alarm when a system abnormality is detected; The communication unit is used to collect system status information in real time and transmit control instructions; The inter-module current sharing control unit is combined with the bidirectional DC / DC converter in each supercapacitor module to eliminate the circulating current between the series-connected supercapacitor modules; The computer is used for human-computer interaction with each unit of the system; The operation process of this device is as follows: Before the device operates normally, it first executes the initialization program, and then sets the number of cycles and cut-off voltage before each module self-recovery. After completion, the communication unit sends a command to the switch control unit, and the device starts to operate. Starting from supercapacitor module #1, the first module switch S of supercapacitor module #1 is turned on. 11 The second module switch S is turned on. 12 Turn off, and the first module switch S of the remaining supercapacitor modules k1 Disconnect, the second module switch S k2 On (k = 2, 3, ..., n), that is, switch S 11 , S 12 The controlled supercapacitor module #1 enters the self-recovery state, and the other supercapacitor modules perform charge and discharge cycles. After the set number of cycles is met, the switch S 11 Turn off, switch S 12 The supercapacitor module 1# ends self-recovery and performs charge and discharge cycle. At the same time, the switch S 21 On, switch S 22 After the device is shut down, supercapacitor module 2# ends the charge and discharge cycle and performs self-recovery. Thereafter, each module switches its state in turn after meeting the number of charge and discharge cycles. After supercapacitor module #n completes self-recovery, it returns to supercapacitor module 1# and restarts the self-recovery and charge and discharge cycle of each module in turn. While the device is running, the operator can conduct human-computer interaction through a computer combined with a communication unit connected to each unit of the device. The communication unit can collect device status information in real time and transmit computer instructions to adjust the device in a timely manner. Taking into account the difference between the initial capacitance and capacitance change of each capacitor, the voltage balancing control of the supercapacitor is carried out through the balancing management device (BMS). The current sharing control unit is combined with the bidirectional DC / DC converter in each supercapacitor module to eliminate the circulating current between the series supercapacitor modules. At the same time, the capacity and internal resistance monitoring unit monitors the capacity and internal resistance of each supercapacitor module and a single supercapacitor. When the capacity is too low or the internal resistance is too high, the charge and discharge cycle is terminated and an alarm is issued through the alarm unit.

2. The modular reconfigurable supercapacitor energy storage management device according to claim 1, characterized in that: It also includes a charge and discharge current control unit and a temperature acquisition unit The charge and discharge current control unit is used to adjust the charge and discharge rate of each supercapacitor module during the cycle, and reasonably set the rate according to the cycle time and load requirements to extend the service life of the system; The temperature acquisition unit is used to monitor the temperature of each module of the system in real time, and to issue an alarm through the alarm unit when the temperature exceeds or falls below a set threshold.

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