Energy storage system and uninterrupted direct current power supply system thereof

By designing an uninterrupted DC power supply system, using dual power switching between AC power grid and energy storage battery, and combining with the battery management system to monitor voltage, the existing energy storage system has solved the problems of low power supply reliability and short power reserve time, and achieved more High power supply reliability and longer power reserve time avoid over-discharge of the battery.

CN222215276UActive Publication Date: 2024-12-20SHANGHAI ELECTRICAL GUOXUAN NEW ENERGY TECH CO LTD
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Patent Information

Application Number
CN202323269957.X
Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
Filing Date
2023-11-30
Publication Date
2024-12-20
Estimated Expiration
2033-11-30

AI Technical Summary

Technical Problem

The existing energy storage systems have problems such as high cost, low power supply reliability and limited power supply time in terms of power supply reliability and power supply time, especially when the external power grid loses power, resulting in battery damage.

Method used

An uninterruptible DC power supply system is designed, and the first switching power supply is input from the AC power grid and rectified into DC voltage, and the second switching power supply is input from the energy storage battery and converted into DC voltage, and connected to the DC bus through a diode, and the AC circuit is broken. The power supply is automatically switched to ensure dual power supply, and the battery management system monitors voltage to prevent over-discharge.

Benefits of technology

It realizes uninterrupted power supply for dual power supplies, increases power supply reliability and power backup time, avoids over-discharge of energy storage batteries, and extends the battery service life and power backup time.

✦ Generated by Eureka AI based on patent content.

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Abstract

The utility model discloses an energy storage system and an uninterrupted direct-current power supply system thereof. The uninterrupted direct-current power supply system comprises a first switching power supply, a second switching power supply, a first diode, a second diode, an alternating-current circuit breaker and a direct-current circuit breaker, the input end of the first switching power supply is connected with an alternating-current power grid through the alternating-current circuit breaker, the output end is connected with the anode of the first diode, and the first switching power supply is used for rectifying input alternating-current voltage and outputting direct-current voltage; the input end of the second switching power supply is connected with an energy storage battery in the energy storage system through the direct-current circuit breaker, and the output end is connected with the anode of the second diode and used for converting the input first direct-current voltage and outputting second direct-current voltage; the cathode of the first diode is connected with the cathode of the second diode and is connected with a direct current bus of the energy storage system; the alternating-current power grid supplies power preferentially, the energy storage battery supplies power after the alternating-current power grid loses power, double-power-source uninterrupted power supply is achieved, power supply reliability is improved, and power backup time is prolonged.
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Description

Technical Field

[0001] The utility model relates to the field of industrial control, in particular to an energy storage system and an uninterruptible direct current power supply system thereof. Background Art

[0002] With the continuous expansion of the energy storage market, the unit cost of electrochemical energy storage systems has been continuously reduced, and industrial and commercial integrated energy storage cabinets have been widely used in industrial parks and commercial centers. This integrated energy storage cabinet has the characteristics of convenient transportation and installation, support for charging and discharging operation in off-grid operation mode, and integration of PCS (Power Conversion System, energy storage converter) and control system in the energy storage cabinet, which has high installation and use flexibility. At present, there are three main ways to obtain power for the control power supply of the integrated energy storage cabinet: Option 1, directly obtain power from the low-voltage AC side of the power grid, and then convert it into a DC power supply for the control power supply; Option 2, supply power through the AC side of a separate UPS (Uninterruptible Power Supply, uninterruptible power supply) device, and then convert it into a DC power supply for the control power supply; Option 3, obtain power from the DC side of the energy storage battery, and then convert the control power supply through DC / DC conversion to require a DC power supply.

[0003] Among them, Solution 1 is the simplest and has the lowest cost, but the power supply reliability is not high. When the external power grid loses power, the integrated energy storage cabinet will also lose control power at the same time, and its control system will not be able to monitor and protect the integrated energy storage cabinet.

[0004] Solution 2 has high power supply reliability and the ability to continue to supply power after the system is disconnected from the grid, but its cost is high and the backup time is limited, usually not exceeding 30 minutes. In addition, the UPS equipment needs to occupy the internal space of the integrated cabinet, which affects the energy density of the energy storage cabinet and reduces the product's competitiveness.

[0005] Solution 3 has a lower cost and a longer backup time, but when the system is in a long-term standby state and is not being charged, the integrated energy storage cabinet control system is powered entirely by the energy storage system battery. If the battery cannot be charged when the battery is almost exhausted, the energy storage battery will continue to supply power to the control system, causing over-discharge of the battery, causing irreversible damage to the battery system, greatly affecting the battery's available capacity and battery cycle life. Utility Model Content

[0006] The technical problem to be solved by the utility model is to overcome the defects of high cost, low power supply reliability and limited backup time in the prior art, and to provide an energy storage system and an uninterruptible DC power supply system thereof.

[0007] The utility model solves the above technical problems through the following technical solutions:

[0008] In a first aspect, an uninterruptible DC power supply system of an energy storage system is provided, the uninterruptible DC power supply system comprising: a first switching power supply, a second switching power supply, a first diode, a second diode, an AC circuit breaker, and a DC circuit breaker;

[0009] The input end of the first switching power supply is connected to the AC power grid through the AC circuit breaker, and the output end is connected to the anode of the first diode. The first switching power supply is used to rectify the input AC voltage and output a DC voltage;

[0010] The input end of the second switching power supply is connected to the energy storage battery in the energy storage system through the DC circuit breaker, and the output end is connected to the anode of the second diode, so as to convert the input first DC voltage and output a second DC voltage;

[0011] The cathode of the first diode is connected to the cathode of the second diode, and is connected to the DC bus of the energy storage system.

[0012] Optionally, the DC circuit breaker includes a first switch and a second switch;

[0013] One end of the first switch is connected to the positive electrode of the energy storage battery, and the other end is connected to the positive input terminal of the second switching power supply;

[0014] One end of the second switch is connected to the negative electrode of the energy storage battery, and the other end is connected to the negative input terminal of the second switching power supply.

[0015] Optionally, the DC circuit breaker further includes a trip, one end of which is connected to an output end of a battery management system for receiving an output signal of the battery management system, and the other end of which is connected to a cathode of the first diode.

[0016] Optionally, the battery management system is used to output a disconnect signal to the tripping device when the voltage value of the energy storage battery is lower than a preset protection voltage;

[0017] The first switch and the second switch are used to be disconnected when the tripping device receives the disconnection signal.

[0018] In a second aspect, an energy storage system is provided, which includes a battery management system, an energy storage battery, and an uninterruptible DC power supply system as described in the first aspect; the uninterruptible DC power supply system is used to supply power to a DC bus of the energy storage system.

[0019] Optionally, the input end of the battery management system is connected to the energy storage battery for monitoring the voltage value of the energy storage battery. Optionally, the energy storage system is an integrated energy storage cabinet.

[0020] Optionally, the energy storage system further includes a sensor, and the sensor is connected to a DC bus of the energy storage system and the battery management system.

[0021] Optionally, the energy storage system further includes fire-fighting equipment, which is connected to the DC bus of the energy storage system and the battery management system.

[0022] Optionally, the energy storage battery is a lithium iron phosphate battery.

[0023] On the basis of conforming to the common sense in the art, the above optional conditions can be arbitrarily combined to obtain the preferred embodiments of the utility model.

[0024] The positive progressive effect of the utility model is that the utility model provides an uninterruptible DC power supply system suitable for an energy storage system, which gives priority to power supply through the AC power grid, and supplies power to the energy storage battery after the AC power grid fails, thereby realizing uninterruptible power supply of dual power sources and increasing power supply reliability and backup time. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of the circuit structure of an uninterruptible DC power supply system of an energy storage system provided in Example 1 of the utility model.

[0026] Figure 2 This is a structural block diagram of an energy storage system provided in Example 2 of the utility model. DETAILED DESCRIPTION

[0027] A preferred embodiment is given below, and the present invention is described more clearly and completely in conjunction with the accompanying drawings.

[0028] Example 1

[0029] This embodiment provides an uninterruptible DC power supply system for an energy storage system, such as Figure 1 As shown, the uninterruptible DC power supply system of this embodiment includes: a first switching power supply, a second switching power supply, a first diode, a second diode, an AC circuit breaker and a DC circuit breaker.

[0030] The input end of the first switching power supply is connected to the AC power grid through an AC circuit breaker, and the output end is connected to the anode of the first diode. The first switching power supply is used to rectify the input AC voltage and output a DC voltage.

[0031] The input end of the second switching power supply is connected to the energy storage battery in the energy storage system through a DC circuit breaker, and the output end is connected to the anode of the second diode, so as to convert the input first DC voltage and output a second DC voltage.

[0032] The cathode of the first diode is connected to the cathode of the second diode and is connected to the DC bus of the energy storage system.

[0033] In a specific implementation example, Figure 1 As shown, the first switching power supply is a switching power supply with an AC220V input and a DC25V output. It can output a DC voltage of 25V in normal operation, one end of which is connected to a 220V power supply on the AC grid side, and the other end is connected to the anode of the first diode. The second switching power supply is a DC switching power supply with a DC1000V input and a DC24V output. It can output a DC voltage of 24V in normal operation, wherein the input end is connected to a DC circuit breaker, and the output end is connected to the anode of the second diode.

[0034] In this embodiment, if Figure 1 As shown, when the AC power grid and the energy storage battery are working normally, the first switching power supply outputs a 25V DC voltage, and the cathode of the first diode outputs a DC 24.3V voltage; at this time, the second switching power supply only provides a 24V DC voltage. Since the cathode of the first diode is connected to the cathode of the first diode, the voltage of the cathode of the second diode, 24.3V, is higher than the voltage of the anode of the first diode, 24V. Therefore, the second diode is cut off, and the second switching power supply will not have current flowing to the DC bus of the energy storage system. The power supply of the DC bus of the energy storage system is all provided by the AC power grid through the first switching power supply. The first diode and the second diode connected in series with the cathodes ensure that the second switching power supply will not be affected by reverse power.

[0035] In this embodiment, if Figure 1 As shown, when the AC power grid fails to supply power, the AC circuit breaker is automatically disconnected, and the first switch power supply stops working. When the DC voltage output by the first diode is lower than the difference between the output voltage of the second switch power supply and the voltage drop of the second diode, that is, lower than 23.3V, the second diode is turned on, and power is taken from the energy storage battery to maintain the power supply to the DC bus of the energy storage system. Specifically, the DC voltage 1000V output by the energy storage battery is converted by the second switch power supply to supply power to the DC bus of the energy storage system.

[0036] In an optional embodiment, Figure 1 As shown, the DC circuit breaker includes a first switch and a second switch; one end of the first switch is connected to the positive electrode of the energy storage battery, and the other end is connected to the positive input end of the second switching power supply; one end of the second switch is connected to the negative electrode of the energy storage battery, and the other end is connected to the negative input end of the second switching power supply.

[0037] In this embodiment, if Figure 1 As shown, when the energy storage battery and the AC power grid are normally connected, the DC circuit breaker and the AC circuit breaker are both in a closed state. At this time, the uninterruptible DC power supply system is powered on, and the first switch power supply and the second switch power supply are working.

[0038] In an optional embodiment, the DC circuit breaker further includes a trip, one end of which is connected to the output end of the battery management system for receiving the output signal of the battery management system, and the other end is connected to the cathode of the first diode. The cathode of the first diode is also connected to the DC bus of the energy storage system, so the DC bus of the energy storage system also provides power for the trip.

[0039] In this embodiment, if Figure 1 As shown, the two input terminals of the battery management system are connected to the positive and negative electrodes of the energy storage battery, respectively, to detect in real time whether the voltage of the energy storage battery is lower than the preset protection voltage. In a specific implementation, the preset protection voltage can be set according to the actual situation. Figure 1 As shown, the DC voltage outputted from the cathode of the first diode or the second diode supplies power to the tripping device, and the battery management system controls the conduction of the circuit where the tripping device is located by outputting a disconnection signal.

[0040] In an optional embodiment, the battery management system is used to output a disconnect signal to the trip when the voltage value of the energy storage battery is lower than a preset protection voltage; the first switch and the second switch are used to disconnect when the trip receives the disconnect signal.

[0041] In this embodiment, if Figure 1 As shown, when the battery management system detects that the voltage of the energy storage battery is lower than the preset protection voltage and there is a risk of over-discharge, the battery management system controls the circuit where the DC circuit breaker is located to be turned on by outputting a disconnection signal, so that the tripping action is performed, thereby disconnecting the first switch and the second switch of the DC circuit breaker, and the energy storage battery stops supplying power, thereby avoiding the situation where the energy storage battery is over-discharged and affects the service life of the energy storage battery.

[0042] Example 2

[0043] This embodiment provides an energy storage system, such as Figure 2 As shown, the energy storage system includes a control system, an energy storage battery, and the uninterruptible DC power supply system as described in Example 1; the uninterruptible DC power supply system is used to supply power to the DC bus of the energy storage system.

[0044] In this embodiment, the energy storage system realizes uninterrupted power supply of the AC grid and the energy storage battery. When power is lost on either the AC grid side or the energy storage battery side, the power supply of the DC bus of the energy storage system is not affected.

[0045] In an optional implementation, the input end of the battery management system is connected to the energy storage battery for monitoring the voltage value of the energy storage battery.

[0046] In this embodiment, the two input terminals of the battery management system are respectively connected to the positive and negative electrodes of the energy storage battery to detect in real time whether the voltage of the energy storage battery is lower than the preset protection voltage. In specific implementation, the preset protection voltage can be set according to actual conditions.

[0047] In an optional embodiment, the energy storage system is an integrated energy storage cabinet. In this embodiment, the number of components required is small, the volume is small, and it can be integrated into the control box of the industrial and commercial energy storage all-in-one machine without taking up additional space for installing batteries.

[0048] In an optional implementation, the energy storage system further includes a sensor, and the sensor is connected to the DC bus of the energy storage system and the battery management system. In this implementation, the energy storage system further includes various sensors that can be used to achieve different functions.

[0049] In an optional embodiment, the energy storage system further includes fire fighting equipment, which is connected to the DC bus and the battery management system of the energy storage system. In this embodiment, the fire fighting equipment is used to start when a fire is detected to ensure the safety of the energy storage system.

[0050] In an optional embodiment, the energy storage battery is a lithium iron phosphate battery. In this embodiment, the lithium iron phosphate battery can discharge about 1% of the power from the end of normal operation discharge (2.8V) to the battery over-discharge light fault warning (2.6V). For the industrial and commercial integrated energy storage cabinet, it can ensure that the energy storage control system can supply power for more than 48 hours, which is much longer than the traditional UPS backup time. If the energy storage battery has residual power before and has not reached the end of discharge, the backup time will be longer.

[0051] Although the specific implementations of the utility model are described above, those skilled in the art should understand that this is only an example, and the protection scope of the utility model is defined by the attached claims. Those skilled in the art can make various changes or modifications to these implementations without departing from the principle and essence of the utility model, but these changes and modifications fall within the protection scope of the utility model.

Claims

1. An uninterruptible DC power supply system for an energy storage system, characterized in that: The uninterruptible DC power supply system comprises: a first switching power supply, a second switching power supply, a first diode, a second diode, an AC circuit breaker and a DC circuit breaker; The input end of the first switching power supply is connected to the AC power grid through the AC circuit breaker, and the output end is connected to the anode of the first diode. The first switching power supply is used to rectify the input AC voltage and output a DC voltage; The input end of the second switching power supply is connected to the energy storage battery in the energy storage system through the DC circuit breaker, and the output end is connected to the anode of the second diode, so as to convert the input first DC voltage and output a second DC voltage; The cathode of the first diode is connected to the cathode of the second diode, and is connected to the DC bus of the energy storage system.

2. The uninterruptible DC power supply system according to claim 1, characterized in that: The DC circuit breaker includes a first switch and a second switch; One end of the first switch is connected to the positive electrode of the energy storage battery, and the other end is connected to the positive input terminal of the second switching power supply; One end of the second switch is connected to the negative electrode of the energy storage battery, and the other end is connected to the negative input terminal of the second switching power supply.

3. The uninterruptible DC power supply system according to claim 1, characterized in that: The DC circuit breaker also includes a trip, one end of which is connected to the output end of the battery management system in the energy storage system for receiving an output signal of the battery management system, and the other end of which is connected to the cathode of the first diode.

4. The uninterruptible DC power supply system according to claim 3, characterized in that: The battery management system is used to output a disconnect signal to the tripping device when the voltage value of the energy storage battery is lower than a preset protection voltage; The first switch and the second switch are used to be disconnected when the tripping device receives the disconnection signal.

5. An energy storage system, characterized in that: The energy storage system includes a battery management system, an energy storage battery, and an uninterruptible DC power supply system according to any one of claims 1 to 4; the uninterruptible DC power supply system is used to supply power to the DC bus of the energy storage system.

6. The energy storage system according to claim 5, characterized in that: The input end of the battery management system is connected to the energy storage battery and is used to monitor the voltage value of the energy storage battery.

7. The energy storage system according to claim 5, characterized in that: The energy storage system is an integrated energy storage cabinet.

8. The energy storage system according to claim 5, characterized in that: The energy storage system further includes a sensor, which is connected to a DC bus of the energy storage system.

9. The energy storage system according to claim 5, characterized in that: The energy storage system further comprises fire fighting equipment, which is connected to the DC bus of the energy storage system and the battery management system.

10. The energy storage system according to any one of claims 5 to 9, characterized in that: The energy storage battery is a lithium iron phosphate battery.