A method and switch device for parallel operation of multiple power storage devices

Abstract

The present invention discloses a method for parallel operation of multiple power storage devices, including S1, each power storage device is connected to the outside world via a set of independent switch devices; S2, when the power storage device is charging or discharging, the switch device corresponding to the power storage device is in a conducting state; otherwise, the switch device corresponding to the power storage device is in a disconnected state. Therefore, the method for parallel operation of multiple power storage devices of the present invention is only in a parallel state in the circuits of each power storage device when the power storage devices are simultaneously energizing or charging, and at other times, each power storage device exists independently and is no longer in a "parallel" state, thereby avoiding mutual charging due to individual differences when multiple power storage devices are connected in parallel, forming an internal circulation. The present invention also discloses a switch device for parallel operation of multiple power storage devices.

Description

Technical Field

[0001] The present invention relates to the field of power storage devices, and in particular to a method and a switch device for parallel operation of multiple power storage devices. Background Art

[0002] In the new energy storage system, in order to increase the system's power storage capacity, it is necessary to increase the number or capacity of power storage devices to achieve this. However, when the power storage devices are used in parallel, the power storage performance of each power storage device cannot be guaranteed to be consistent, which will cause imbalance in the charging and discharging process of each battery and reverse charging and discharging during the charging and discharging process. This will seriously affect the working efficiency of the entire energy storage system and may even cause accidents such as fires due to uncontrollable reverse charging.

[0003] Therefore, a method and device for realizing parallel operation of power storage devices are needed. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method for realizing parallel operation of electric storage devices and a switch device for parallel operation of electric storage devices.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A method for parallel operation of multiple power storage devices comprises the following steps:

[0007] S1. Each power storage device is connected to the outside world through an independent switch device;

[0008] S2. When the power storage device is charging or discharging, the switch device corresponding to the power storage device is in the on state; otherwise, the switch device corresponding to the power storage device is in the off state.

[0009] Compared with the prior art, the present invention has the following technical effects: when multiple power storage devices are connected in parallel to supply power to the outside or are charged, the circuit is turned on, and all the power storage devices supply power to the outside or are charged at the same time. When the external power supply or charging task is completed, the independent switch device corresponding to each power storage device disconnects the power storage device from the outside, so that each power storage device exists independently and is no longer in a "parallel" state, thereby avoiding mutual charging due to individual differences when multiple power storage devices are connected in parallel, forming an internal circulation.

[0010] A switch device for parallel operation of multiple power storage devices, comprising an input module, a data processing module, and an output module; the input module is electrically connected to the input end of the data processing module, and the output end of the data processing module is electrically connected to the input end of the output module; the input module comprises a multi-channel passive switch signal input end for receiving control signals and fault signals; the data processing module is used for comprehensively analyzing the control signals and fault signals received by the input module, and sending action instructions to the output module; the output module is used for executing the action instructions sent by the data processing module.

[0011] Compared with the prior art, the present invention has the following technical effects:

[0012] This device is arranged between the power storage device and the outside world, and acts as an independent switch. It accepts the dispatch of the superior system. When the power storage device needs to discharge or charge, the superior system sends a "connect" command to the input module. The input module also collects fault signals at all times. After receiving the "connect" command, the data processing module determines whether there is a fault signal at present. If there is no fault signal, the output module executes the "connect" command to connect the power storage device with the outside world. If the device receives the "connect" command, but there is a fault signal at the same time, the data processing module does not send an action command to the output module, and keeps the power storage device disconnected from the outside world. This ensures that the power storage device is only electrically connected to the outside world during the process of discharging and charging, and is not electrically connected to the outside world at other times, avoiding the internal circulation problem of mutual charging and discharging caused by the difference in the performance of the power storage device itself under the connection relationship of multiple power storage devices connected in parallel to supply power to the outside world.

[0013] Based on the above technical solution, the present invention can also be improved as follows.

[0014] Preferably, the input module further comprises a multi-channel sensor input interface, wherein the sensor input interface is electrically connected to a voltage sensor and a current sensor;

[0015] The data processing module is used to perform A / D conversion on the analog signal transmitted by the input module, perform incremental integral calculation on the voltage value and the current value, compare its historical records with the preset voltage threshold and current threshold, and send the opening and closing instructions of the power switch to the output module accordingly;

[0016] The output module performs the connection and disconnection actions between the power storage device and the outside world according to the opening and closing instructions sent by the data processing module.

[0017] The beneficial effect of adopting the above further scheme is that by calculating the incremental integral of voltage and current, it can be determined whether the current power storage device is in a charging state or a discharging state. For example, if the incremental integral of voltage is calculated as a positive value, it means that the voltage is constantly rising, indicating that the power storage device is in a charging state. On this basis, if the incremental integral of current is getting smaller and smaller, it means that the power storage device is close to being full. When the incremental integral of current is below the preset current threshold within a certain period of time, it is considered that the power storage device is already full. The data processing module can send a disconnection instruction to the output module based on this, and the output module disconnects the electrical connection between the power storage device and the outside world. On the contrary, when the incremental integral of voltage is calculated as a negative value, it means that the battery is in a discharging state. When the incremental integral of voltage drops below the preset voltage threshold, it is considered that the battery power is insufficient. The data processing module sends a disconnection instruction to the output module, and the output module disconnects the electrical connection between the power storage device and the outside world. In this way, the internal circulation problem caused by the parallel connection of multiple power storage devices is avoided.

[0018] Preferably, the input module is also electrically connected to a temperature sensor; the data processing module is also used to perform incremental integral calculations on the temperature value and compare it with a temperature threshold, and accordingly send a start / stop signal of the heat dissipation device to the output module; the output module executes the start or stop action of the peripheral heat dissipation device according to the start / stop signal of the heat dissipation device sent by the data processing module.

[0019] The beneficial effect of adopting the above further scheme is that the temperature sensor is used to detect the temperature of the power storage device, and continuously performs incremental integral calculations on the temperature value, so as to judge the current health status of the power storage device, and according to the temperature changes, promptly start the external heat dissipation equipment to interfere with the temperature of the power storage device, so as to avoid thermal runaway events of the power storage device.

[0020] Preferably, the output module further comprises a plurality of output ports for feeding power to third-party instruments.

[0021] The beneficial effect of adopting the above further solution is that it can conveniently provide power to third-party instruments, thereby improving the convenience of putting the device into use.

[0022] Preferably, the output module includes multiple high-side isolation relays, DC relays and high-power diodes; the high-side isolation relays are used to drive and connect peripheral heat dissipation equipment and peripheral alarm equipment; the DC relay is connected in series with the high-power diode, the other end of the DC relay is connected to the power storage device, and the other end of the high-power diode is connected to the outside world.

[0023] The beneficial effect of adopting the above further scheme is that the unidirectional conductivity of the high-power diode is utilized to further ensure that no internal circulation current is generated between the power storage devices. That is, when supplying power to the outside, the high-power diode can only conduct from the power storage device side to the outside world and cannot be charged in reverse, thereby avoiding the generation of internal circulation current.

[0024] Preferably, each power storage device is provided with a charging circuit and a discharging circuit, and a high-power diode and a DC relay are connected to the charging circuit and the discharging circuit respectively.

[0025] The beneficial effect of adopting the above further scheme is that, through the overall management of the superior control system, the power storage device is controlled to connect the charging circuit or the discharging circuit, ensuring that only one of the charging circuit and the discharging circuit can be connected at any time, ensuring that multiple energy storage devices can supply power to the outside or charge at the same time, but cannot charge and discharge each other, avoiding the generation of internal circulation.

[0026] Preferably, the DC relay on the charging circuit is interlocked with the charging relay on the discharging circuit, and when one relay is turned on, the other relay is turned off.

[0027] The beneficial effect of adopting the above further scheme is that, through the interlocking function of the relay, it is ensured that the discharge circuit is disconnected when the charging circuit is connected, and the charging circuit is disconnected when the discharge circuit is connected, ensuring that the charging and discharging circuits of the energy storage device are not connected at the same time, avoiding the generation of internal circulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is an application scenario diagram of the present invention;

[0029] Figure 2 It is a functional block of a switch device for parallel operation of multiple power storage devices of the present invention;

[0030] In the accompanying drawings, the component names represented by the reference numerals are listed as follows:

[0031] 1. Input module; 2. Data processing module; 3. Output module; X1. First power storage device; X2. Second power storage device; X3. Third power storage device; X4. Fourth power storage device; K1. First independent switch device; K2. Second independent switch device; K3. Third independent switch device; K4. Fourth independent switch device; K5. Fifth independent switch device; K6. Sixth independent switch device; G1. First high-voltage device; G2. Second high-voltage device; PCS. AC / DC inverter. DETAILED DESCRIPTION

[0032] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0033] A method for parallel operation of multiple power storage devices comprises the following steps:

[0034] S1. Each power storage device is connected to the outside world through an independent switch device;

[0035] S2. When the power storage device is charging or discharging, the switch device corresponding to the power storage device is in the on state; otherwise, the switch device corresponding to the power storage device is in the off state.

[0036] Please refer to Figure 1 As shown, it is an application scenario diagram of the present invention.

[0037] The first power storage device X1 is electrically connected to the first independent switch device K1, the second power storage device X2 is electrically connected to the second independent switch device K2, and the outlet terminals of the first independent switch device K1 and the second independent switch device K2 are connected in parallel and then connected to the first high-voltage device G1.

[0038] The third power storage device X3 is electrically connected to the third independent switch device K3, the fourth power storage device X4 is electrically connected to the fourth independent switch device K4, and the outlet terminals of the third independent switch device K3 and the fourth independent switch device K4 are connected in parallel and connected to the second high-voltage device G2.

[0039] The outgoing terminal of the first high-voltage device G1 is electrically connected to the fifth independent switch device K5, and the outgoing terminal of the second high-voltage device G2 is electrically connected to the sixth independent switch device K6, and then connected in parallel to the AC / DC inverter PCS.

[0040] Therefore, each energy storage device is in a parallel state in the circuit only when supplying power to the outside or charging at the same time. During the rest of the time, the circuit is disconnected by an independent switching device, and each energy storage device is in an independent state, and no internal circulation is formed due to the differences between the energy storage devices.

[0041] The switch device for parallel operation of multiple power storage devices comprises an input module 1, a data processing module 2, and an output module 3; the input module is electrically connected to the input end of the data processing module, and the output end of the data processing module is electrically connected to the input end of the output module;

[0042] The input module includes a multi-channel passive switch signal input terminal and a multi-channel sensor input interface, wherein the sensor input interface is electrically connected to a voltage sensor, a current sensor, and a temperature sensor; and is used to receive control signals and fault signals;

[0043] The data processing module is used to comprehensively analyze the control signals and fault signals received by the input module, perform incremental integral calculations on the analog signals, compare the historical record values ​​with the preset threshold values, etc., and send action instructions to the output module; for example, perform incremental integral calculations on the voltage and current to determine whether the current state is charging or discharging, whether it is fully charged or whether the power has been exhausted, so as to conclude whether it is necessary to cut off the electrical connection between the power storage device and the outside world; or perform incremental integral calculations on the temperature data to determine whether the current power storage device requires an external heat dissipation device to perform temperature interference on the power storage device, and send a signal to the output module to control the cutting off or connecting of the electrical connection between the power storage device and the outside world or to start the external heat dissipation device.

[0044] The input signal of the independent switch device of the present invention is a conventional digital signal and an analog signal (4-20mA / 0-10v), which meets the signal output of most controller instruments and improves the versatility of the invention; the signal filtering times, upper and lower limit compensation, fault threshold correction, etc. can be manually set to improve the accuracy of the data and achieve precise control of the equipment. The main control unit adopts a high-power diode, supports a wide voltage and current of 0-1600V / 0-500A, and meets more than 95% of the design requirements of energy storage systems; the overall modular design is easy to transplant into different energy storage system electrical circuits.

[0045] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for parallel operation of multiple power storage devices, characterized in that: The following steps are involved: S1. Each power storage device is connected to the outside world through an independent switch device; S2. When the electric storage device is charging or discharging, the switch device corresponding to the electric storage device is in the on state; otherwise, the switch device corresponding to the electric storage device is in the off state; The switch device comprises an input module, a data processing module and an output module; the input module is electrically connected to the input end of the data processing module, and the output end of the data processing module is electrically connected to the input end of the output module; The input module includes a multi-channel passive switch signal input terminal for receiving control signals and fault signals; The data processing module is used to comprehensively analyze the control signals and fault signals received by the input module and send action instructions to the output module; The output module is used to execute the action instructions sent by the data processing module; Each power storage device is provided with a charging circuit and a discharging circuit, and a high-power diode and a DC relay are connected to the charging circuit and the discharging circuit respectively; the DC relay on the charging circuit is interlocked with the charging relay on the discharging circuit, and when one relay is turned on, the other relay is turned off; When the power storage device needs to discharge or charge, the upper system sends a "connect" command to the input module. The input module also collects fault signals at all times. After receiving the "connect" command, the data processing module determines whether there is a fault signal at present. If there is no fault signal, the output module executes the "connect" command to connect the power storage device with the outside world. If the device receives the "connect" command, but there is a fault signal at the same time, the data processing module does not send an action command to the output module to keep the power storage device disconnected from the outside world. The data processing module is used to perform A / D conversion on the analog signal transmitted by the input module, perform incremental integral calculation on the voltage value and the current value, compare its historical records with the preset voltage threshold and current threshold, and send the power switch on / off instruction to the output module accordingly; The output module includes multiple high-side isolation relays, DC relays and high-power diodes; the high-side isolation relays are used to drive and connect peripheral heat dissipation equipment and peripheral alarm equipment; the DC relay is connected in series with the high-power diode, the other end of the DC relay is connected to the power storage device, and the other end of the high-power diode is connected to the outside world.

2. A method for parallel operation of multiple power storage devices according to claim 1, characterized in that: The input module also includes a multi-channel sensor input interface, which is electrically connected to a voltage sensor and a current sensor; the output module executes the connection and disconnection actions between the power storage device and the outside world according to the start and stop instructions sent by the data processing module.

3. A method for parallel operation of multiple power storage devices according to claim 2, characterized in that: The input module is also electrically connected to a temperature sensor; The data processing module is also used to perform incremental integral calculation on the temperature value and compare it with the temperature threshold, and send a start / stop signal of the heat dissipation device to the output module accordingly; The output module starts or stops the peripheral heat dissipation device according to the start / stop signal of the heat dissipation device sent by the data processing module.

4. A method for parallel operation of multiple power storage devices according to claim 3, characterized in that: The output module also includes a plurality of output ports for feeding power to third-party instruments.

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