Fuse Cutting Acceleration Assembly, Power Conversion Configuration, and Energy Storage System

Abstract

The present invention relates to a fuse cut-off acceleration assembly (24) designed to be arranged between the bidirectional voltage converters (5, 6) of a power conversion device (1) and the energy storage devices (20, 22), the energy storage devices having at least one electrochemical energy converter (7 - 10), in particular an energy converter designed as a flow battery, for example a redox flow battery, the fuse cut-off acceleration assembly (24) comprising: a. two connections (26, 28) on the energy storage device side; b. two connections (30, 32) on the power conversion device side; c. at least one fuse (34, 36) connected between one of the connections (26, 28) on the energy storage device side and one of the connections (30, 32) on the power conversion device side; d. an energy accumulator (38) formed in particular as a voltage source, having a predetermined internal resistance and electrically connected in parallel to the connections (26, 28) on the energy storage device side.

Description

Technical Field

[0001] The present invention relates to a fuse cut-off acceleration assembly designed to be arranged between a bidirectional voltage converter of a power conversion device and an energy storage device, the energy storage device having at least one electrochemical energy converter, in particular an energy converter designed as a flow battery, for example a redox flow battery. The present invention further relates to a power conversion configuration and an energy storage system.

Background Art

[0002] Alternative energy is becoming increasingly important. The problem of alternative energy such as solar energy or wind energy is that the timing of energy generation cannot be controlled and surplus energy must be temporarily stored so that it can be used even during periods when energy generation is not possible. Therefore, it is necessary to use an energy storage system.

[0003] As an energy storage device, a flow battery or an electrochemical energy converter for a flow battery, in particular for a redox flow battery, is suitable, the redox flow battery having an electrolyte circulation device, i.e., in the circulation process, one or more electrolytes are supplied from a storage tank to the electrochemical energy converter and electrolyte pipes for returning from the electrochemical energy converter to their respective storage tanks. At this time, the electrochemical energy converter includes at least one reaction cell having two electrodes and an ion conductive membrane, preferably a plurality of individual cells connected electrically. At this time, these plurality of individual cells are preferably connected in parallel and supplied with electrolyte, each having an inlet region for introducing the electrolyte into the reaction cell and an outlet region for discharging the electrolyte from the reaction cell.

[0004] A power conversion device for charging and discharging an energy storage device is disclosed, for example, in Patent Document 1. Patent Document 1 discloses a power conversion device for charging and discharging an energy storage device in the form of a flow battery, particularly a redox flow battery. This power conversion device includes a bidirectional voltage converter connected to a power supply network and at least one electrochemical energy converter. The power conversion device includes a control device that is connected to the voltage converter, controls the voltage converter with respect to the direction of power flow, and can control a plurality of energy storage peripheral devices depending on the direction of power flow of the voltage converter specified to the control device. These energy storage peripheral devices are, for example, a pump for circulating the electrolyte of the flow battery, a flow control device for controlling the flow rate of the electrolyte, a temperature control device for setting the temperature of the electrolyte, or a pressure control device for setting the pressure of the electrolyte.

[0005] When a voltage source, i.e., for example, the above-described energy storage device, short-circuits in a load, i.e., in the above-described current and / or voltage converter, or in the middle thereof, usually, a current flows that cuts off a fuse electrically disposed and connected between the voltage source and the load. In this specification, the term "fuse" means an electrical overcurrent protection device, i.e., a protection device designed to reduce or cut off the flow of current when an overcurrent occurs. This is also referred to as "tripping". Such fuses are usually designed to trip according to a predetermined time-current characteristic. Therefore, a small overcurrent often causes the fuse to trip only after a much longer time has elapsed compared to a much larger overcurrent. Such fuses are described, for example, in Patent Document 2. This becomes difficult when the short-circuit impedance of the voltage source is not much different from the normal impedance. When using a redox flow battery as a voltage source or an energy storage device, the internal resistance is often in the range of two-digit mΩ. As a result, the short-circuit current expected in an unfavorable case, for example, at a low charging voltage, is about several times the expected load current. Thereby, the fuse does not trip or trips very slowly, for example, only after several seconds. When the fuse is sized to slightly exceed the rated current, this leads to a large power loss (in the range of dozens of watts) and shortens the service life in normal operation.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] Accordingly, an object of the present invention is to provide an improved fuseability for an energy storage system having an electrochemical energy storage device.

Means for Solving the Problem

[0008] This problem is solved by a fuse cut-off acceleration assembly designed to be arranged between a bidirectional voltage converter of a power conversion device and an energy storage device, wherein the energy storage device has at least one electrochemical energy converter, in particular an energy converter designed as a flow battery, for example a redox flow battery, and the fuse cut-off acceleration assembly comprises · two connection parts on the energy storage device side, · two connection parts on the power conversion device side, · at least one fuse connected between one of the connection parts on the energy storage device side and one of the connection parts on the power conversion device side, · an energy accumulator having a predetermined internal resistance and electrically connected in parallel to the connection part on the energy storage device side.

[0009] By this measure, the energy accumulator is connected in parallel on the energy storage device side, and the internal resistance of the energy storage device is effectively reduced. As a result, the size of the fuse can be determined so as to surely cut off in case of a short circuit, and moreover, no significant loss occurs during normal operation. The fuse cut-off acceleration assembly can be easily retrofitted to an existing energy storage system.

[0010] In the present specification, the energy accumulator is understood to be an accumulator device formed to store electrical energy. In particular, this can be formed as a voltage source.

[0011] The energy accumulator can be designed to be miniaturized to a fraction of the size, in terms of spatial size, compared to an energy storage device having at least one electrochemical energy converter, in particular an energy converter formed as a flow battery, for example a redox flow battery. The energy accumulator can also be designed to be miniaturized by more than one hundredth.

[0012] The energy accumulator can be designed to have a reduced capacitance to a fraction, in terms of capacitance, compared to an energy storage device having at least one electrochemical energy converter, in particular an energy converter formed as a flow battery, for example a redox flow battery. The energy accumulator can also be designed to have a capacitance reduction of more than one hundredth.

[0013] The energy accumulator can be designed to be lighter by a fraction, in terms of weight, compared to an energy storage device having at least one electrochemical energy converter, in particular an energy converter formed as a flow battery, for example a redox flow battery. The energy accumulator can also be designed to have a weight reduction of more than one hundredth.

[0014] When the internal resistance of the energy accumulator is smaller than the internal resistance of the energy storage device, particularly when it is one tenth, preferably one twentieth smaller than the internal resistance of the energy storage device, a particularly reliable fuse cut-off can be achieved.

[0015] When the internal resistance of the energy accumulator is at least small enough such that the current flowing through the fuse during a short circuit on the power conversion device side is more than twice the rated load current when charging or discharging the energy storage device, further advantages occur. The internal resistance of the energy accumulator can be within the range of 1 mΩ.

[0016] When the internal resistance of the energy accumulator is smaller than the internal resistance of the voltage converter, it contributes to a reliable fuse cut-off.

[0017] The internal resistance of the energy accumulator can be at least substantially equal to the resistance of the wiring between the energy storage device and the power conversion device, particularly the resistance of the wiring between the connection part on the energy storage device side and the connection part on the power conversion device side.

[0018] The energy accumulator can be formed as a capacitor. Thereby, the formation of the energy conversion device becomes particularly simple. For example, the capacitor can be formed as an electrolytic capacitor (abbreviated as Elko).

[0019] A further fuse can be arranged between the other of the connection parts on the energy storage device side and the other of the connection parts on the power conversion device side. The energy storage system provided with the fuse cut-off acceleration assembly according to the present invention becomes thereby even safer.

[0020] The scope of the present invention further includes a power conversion configuration, and the power conversion configuration · a power conversion device having at least one bidirectional voltage converter for charging and discharging the energy storage device, wherein the energy storage device has at least one electrochemical energy converter, particularly an energy converter designed as a flow battery, for example a redox flow battery, · a fuse cut-off acceleration assembly according to the present invention, which is connected to the bidirectional voltage converter by the connection part on the power conversion device side and can be connected to the electrochemical energy converter by the connection part on the energy storage device side.

[0021] Thereby, the above advantages are obtained.

[0022] Furthermore, the present invention relates to an energy storage system, and the energy storage system includes a power conversion device having at least one bidirectional voltage converter, and an energy storage device connected to the bidirectional voltage converter and having at least one electrochemical energy converter, and a fuse cut-off acceleration assembly according to the present invention is arranged between the bidirectional voltage converter and the energy storage device.

[0023] Such an energy storage system can operate with low losses and can quickly transition to a safe state in the event of a short circuit.

[0024] The energy storage device can include a plurality of electrochemical energy converters electrically connected in parallel or in series. The energy storage device can be formed as a stack.

[0025] Further features and advantages of the present invention can be derived from the following detailed description of embodiments of the invention, which shows details essential to the invention, and from the claims, with reference to the figures of the drawings. The features shown therein do not necessarily have to be understood to scale and are shown so that the special features of the present invention can be clearly visualized. The various features can be realized in variants of the present invention individually or in any combination.

[0026] In schematic drawings, embodiments of the present invention are shown and will be described in more detail in the following description.

Brief Description of the Drawings

[0027]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0028] FIG. 1 shows an energy storage system 100 including a power conversion device 1 having a first voltage converter 2 connectable to a single-phase or polyphase power supply network 3. The first voltage converter 2 can be formed in particular as a bidirectional AC / DC converter. The first voltage converter 2 is connected to an intermediate circuit 4, to which further second and third voltage converters 5, 6 are connected. The voltage converters 5, 6 can be formed, for example, in particular as bidirectional DC / DC converters, each capable of converting a power of 5 kW or more. How the voltage converters 5, 6 can be formed is described, for example, in Patent Document 1.

[0029] The first voltage converter 2 can be connected to more intermediate circuits 4 than the two shown voltage converters 5, 6. The voltage converters 5, 6 are each connected to an energy storage device 20, 22. The energy storage devices 20, 22 can have one or more electrochemical energy converters 7 to 10. In the illustrated embodiment, the voltage converter 5 is connected to the electrochemical energy converter 7, and the voltage converter 6 is connected to the electrochemical energy converters 8 to 10. The electrochemical energy converters 8 to 10 are connected in series. They can also be connected in parallel to the voltage converter 6.

[0030] The voltage of the intermediate circuit 4 can be made considerably higher than the voltage of the energy converters 7 to 10. Thereby, the power conversion device 1 becomes particularly efficient.

[0031] Furthermore, the power conversion device 1 includes a control device 11 connected to and configured to control both the first voltage converter 2 and the voltage converters 5, 6. In particular, the control device 11 is configured to control the power flow in the voltage converters 5, 6, in particular the direction of the power flow. In this case, the control device 11 can control the voltage converters 5, 6 such that, for example, the energy from the electrochemical energy converter 7 is transferred to the electrochemical energy converter 8 via the voltage converter 5, the intermediate circuit 4, and the voltage converter 6, or vice versa. During this transfer, the control device 11 can turn off the voltage converter 2.

[0032] Furthermore, the control device 11 can control the voltage converters 2, 5, and 6 so that the flow of power flows from the power supply network 3 through the voltage converter 2, the intermediate circuit 4, and the voltage converters 5 and 6 to the electrochemical energy converters 7 to 10. The control device 11 can also control only one of the voltage converters 5 and 6, whereby, for example, energy transfer can be made to occur only in the energy converter 7. Furthermore, the control device 11 can also control the flow of power so that, for example, the energy stored in the energy converter 7 is supplied to the power supply network 3 via the voltage converter 5, the intermediate circuit 4, and the voltage converter 2.

[0033] The fuse cut-off acceleration assembly 24, as will be described with reference to FIG. 2, is arranged between the power conversion device 1 and each of the energy storage devices 20 and 22.

[0034] FIG. 2 shows the fuse cut-off acceleration assembly 24 in detail. The fuse cut-off acceleration assembly 24 has two connection parts 26 and 28 on the energy storage device side and two connection parts 30 and 32 on the power conversion device side. The first fuse 34 is arranged between the connection parts 26 and 30. The optional second fuse 36 is arranged between the connection parts 28 and 32. The energy accumulator 38 formed as a voltage source is connected in parallel to the connection parts 26 and 28 on the energy storage device side.

[0035] The energy accumulator 38 can be formed particularly as a capacitor, for example as an electrolytic capacitor. The energy accumulator 38 has an internal resistance that is significantly lower than the internal resistance of the energy storage device 20. For example, the internal resistance of the energy accumulator 38 is 1 mΩ and the internal resistance of the energy storage device 20 is 20 mΩ.

[0036] Wiring 40 and 42 can each have a wiring resistance within the range of the internal resistance of the energy accumulator. For example, wiring 40 and 42 can have a wiring resistance of 1 mΩ. The internal resistance of the energy accumulator 38 is preferably smaller than the internal resistance of the voltage converter 5. The internal resistance of the voltage converter 5 can be, for example, 3 mΩ.

[0037] Since the energy accumulator 38 is connected in parallel with the energy storage device 20, the internal resistance of the energy storage device 20 is effectively reduced. As a result, when a short circuit occurs, the fuse 34 (and fuse 36) is surely and quickly cut off. The internal resistance of the energy accumulator 38 can be in the range of 1 / 100 to 1 / 10 of the internal resistance of the energy storage device 20.

[0038] The energy accumulator 38 preferably has a sufficient capacity to safely cut off the fuses 34 and 36 when a short circuit occurs.

Explanation of symbols

[0039] 1 Power conversion device 5, 6 Voltage converter 7, 8, 9, 10 Electrochemical energy converter 20, 22 Energy storage device 24 Fuse cut-off acceleration assembly 26, 28 Connection part on the energy storage device side 30, 32 Connection part on the power conversion device side 34, 36 Fuse 38 Energy accumulator 40, 42 Wiring 100 Energy storage system

Claims

1. A fuse cut-off acceleration assembly (24) designed to be arranged between the bidirectional voltage converters (5, 6) of a power conversion device (1) and an energy storage device (20, 22), wherein the energy storage device (20, 22) has at least one electrochemical energy converter (7 - 10), in particular an energy converter designed as a flow battery, for example a redox flow battery. a. Two connection parts (26, 28) on the energy storage device side; b. Two connection parts (30, 32) on the power conversion device side; c. At least one fuse (34, 36) connected between one of the connection parts (26, 28) on the energy storage device side and one of the connection parts (30, 32) on the power conversion device side; d. An energy accumulator (38), in particular formed as a voltage source, having a predetermined internal resistance and electrically connected in parallel to the connection parts (26, 28) on the energy storage device side. The fuse cut-off acceleration assembly (24) is provided with the above components.

2. The internal resistance of the energy accumulator (38) is smaller than the internal resistance of the energy storage device (20, 22), in particular one-tenth, preferably one-twentieth smaller than the internal resistance of the energy storage device (20, 22). The fuse cut-off acceleration assembly (24) according to Claim 1 is characterized by this.

3. The internal resistance of the energy accumulator (38) is at least small enough so that the current flowing through the fuse (34, 36) during a short circuit on the power conversion device side is more than twice as large as the rated load current when charging or discharging the energy storage device (20, 22). The fuse cut-off acceleration assembly (24) according to Claim 1 or 2 is characterized by this.

4. The internal resistance of the energy accumulator (38) is smaller than the internal resistance of the voltage converters (5, 6). The fuse cut-off acceleration assembly (24) according to any one of Claims 1 to 3 is characterized by this.

5. The internal resistance of the energy accumulator (38) is at least substantially the same as the resistance of the wiring between the energy storage device (20, 22) and the power conversion device (1), in particular, the resistance of the wiring (40, 42) between the connection parts (26, 28) on the energy storage device side and the connection parts (30, 32) on the power conversion device side. The fuse cut-off acceleration assembly (24) according to any one of claims 1 to 4 is characterized by this.

6. The fuse cut-off acceleration assembly (24) according to any one of claims 1 to 5, characterized in that the energy accumulator (38) is formed as a capacitor.

7. A further fuse (34, 36) is arranged between the other of the connection parts (26, 28) on the energy storage device side and the other of the connection parts (30, 32) on the power conversion device side. The fuse cut-off acceleration assembly (24) according to any one of claims 1 to 6 is characterized by this.

8. A power conversion configuration, a. A power conversion device (1) having at least one bidirectional voltage converter (5, 6) for charging and discharging an energy storage device (20, 22), where the energy storage device (20, 22) has at least one electrochemical energy converter (7 to 10), in particular, an energy converter designed as a flow battery, for example, a redox flow battery. b. A fuse cut-off acceleration assembly (24) according to any one of claims 1 to 7, which is connected to the bidirectional voltage converter (5, 6) by connection parts (30, 32) on the power conversion device side and can be connected to the electrochemical energy converter (7 to 10) by connection parts (26, 28) on the energy storage device side. The power conversion configuration is provided with this.

9. A power conversion device (1) having at least one bidirectional voltage converter (5, 6), An energy storage system (100) comprising an energy storage device (20, 22) connected to the bidirectional voltage converter (5, 6) and having at least one electrochemical energy converter (7 to 10), An energy storage system (100), characterized in that a fuse cut-off acceleration assembly (24) according to any one of claims 1 to 7 is arranged between the bidirectional voltage converter (5, 6) and the energy storage device (20, 22).

10. The energy storage system (100) according to claim 9, wherein the energy storage device (20, 22) includes a plurality of electrochemical energy converters (7 to 10) electrically connected in parallel or in series.

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