阅读说明：本技术 液流电池系统 (Flow battery system ) 是由 赵明 郭威 许贤昶 黄峰 陈奇 于 2020-07-09 设计创作，主要内容包括：本申请提供了一种液流电池系统,该液流电池系统包括多个电池罐和多组电池堆,每个电池罐分别对应一组电池堆,同一组电池堆中的各液流电池堆共同连接该组电池堆对应的电池罐,其中,同一组电池堆中的各液流电池堆分属不同的电池簇,同一电池簇中的液流电池堆依次串联连接；所述液流电池系统以电池簇为能量单元,与外界进行能量交换。本申请的有益效果在于：通过将不同电池罐对应的液流电池对进行串联,显著提升液流电池系统的电压等级；在相同电流下,能极大提升液流电池系统容量；同时降低了现有技术中电池堆串联效率损失大的现状,提升液流电池充放电转换效率。(The application provides a flow battery system, which comprises a plurality of battery tanks and a plurality of groups of battery stacks, wherein each battery tank corresponds to one group of battery stacks, each flow battery stack in the same group of battery stacks is connected with the battery tank corresponding to the group of battery stacks, each flow battery stack in the same group of battery stacks belongs to different battery clusters, and the flow battery stacks in the same battery cluster are sequentially connected in series; the flow battery system takes the battery cluster as an energy unit and exchanges energy with the outside. The beneficial effect of this application lies in: the flow battery pairs corresponding to different battery tanks are connected in series, so that the voltage level of the flow battery system is remarkably improved; under the same current, the system capacity of the flow battery can be greatly improved; meanwhile, the current situation of high loss of series efficiency of the cell stack in the prior art is reduced, and the charge-discharge conversion efficiency of the flow battery is improved.)

1. A flow battery system comprises a plurality of battery tanks and a plurality of groups of battery stacks, each battery tank corresponds to one group of battery stacks, each flow battery stack in the same group of battery stacks is connected with the battery tank corresponding to the group of battery stacks, and the flow battery system is characterized in that,

each flow battery stack in the same battery stack group belongs to different battery clusters, and the flow battery stacks in the same battery cluster are sequentially connected in series;

the flow battery system takes the battery cluster as an energy unit and exchanges energy with the outside.

2. The flow battery system of claim 1, wherein each flow battery stack has a group number and a cluster number.

3. The flow battery system of claim 1, wherein the number of flow stacks in each set of stacks is the same.

4. The flow battery system according to any one of claims 1-3, further comprising a plurality of power electronic converters in one-to-one correspondence with battery clusters, each battery cluster being connected to the DC terminal of a respective one of the power electronic converters.

5. The flow battery system of claim 4, wherein the power electronic converter is a DC/AC converter or a combination of a DC/DC converter and a DC/AC converter.

6. The flow battery system of claim 4, further comprising a transformer, wherein the ac terminal of the power electronic converter is connected to the transformer.

7. The flow battery system of claim 6, wherein the transformer is a phase shifting transformer.

8. The flow battery system of claim 7, wherein the AC terminal of the power electronic converter is connected with secondary windings of a phase-shifting transformer, and the number of the secondary windings of the phase-shifting transformer is not less than the number of the battery clusters.

9. The flow battery system of claim 7, wherein the phase shifting transformer is configured to reduce current harmonics on a high-voltage side of the transformer and improve power quality of the flow system.

10. The flow battery system of claim 6, further comprising a switch cabinet, wherein the switch cabinet is connected to the transformer.

Technical Field

The application relates to the technical field of energy storage, in particular to a flow battery system.

Background

The flow battery is an electrochemical energy storage mode widely applied in the field of energy storage, the flow battery technology has the advantages of long service life, environmental friendliness, high safety and reliability, strong adaptability, low cost and the like, the output power is thousands of watts to tens of megawatts, the energy storage capacity can reach more than hours, and the flow battery is a large-scale fixed energy storage occasion and is one of large-scale energy storage technical routes.

However, the current flow battery has many disadvantages, such as low capacity of the flow battery under the same current level due to low voltage of the flow battery; under a low-voltage and high-current system, the energy storage efficiency of the flow battery is low; the single cell stack in the flow battery has small power and large quantity, and the quantity of transformers is large when the cell stack is isolated, so that the total volume of the flow battery is large and the occupied area is large; the circuit connection form of the conventional flow battery has the risk of forming common-mode circulation, and the common-mode circulation not only generates extra loss and influences the conversion efficiency, but also has serious electromagnetic interference and influences the normal operation of various devices.

Disclosure of Invention

In view of the above, the present application is developed to provide a flow battery system that overcomes, or at least partially solves, the above-mentioned problems.

According to one aspect of the application, a flow battery system is provided, which comprises a plurality of battery tanks and a plurality of groups of battery stacks, wherein each battery tank corresponds to one group of battery stacks, and each flow battery stack in the same group of battery stacks is connected with the battery tank corresponding to the group of battery stacks, wherein each flow battery stack in the same group of battery stacks belongs to different battery clusters, and the flow battery stacks in the same battery cluster are sequentially connected in series;

the flow battery system takes the battery cluster as an energy unit and exchanges energy with the outside.

Preferably, in the above-described flow battery system, each flow battery stack has a group number and a cluster number.

Preferably, in the above-described flow cell system, the number of flow cell stacks in each stack group is the same.

Preferably, in the above flow battery system, the flow battery system further includes a plurality of power electronic converters corresponding to the battery clusters one to one, and each battery cluster is connected to the dc terminal of one power electronic converter.

Preferably, in the above-described flow battery system, the power electronic converter is a DC/AC converter, or a combination of a DC/DC converter and a DC/AC converter.

Preferably, in the above flow battery system, the flow battery system further includes a transformer, and the ac terminal of the power electronic converter is connected to the transformer.

Preferably, in the above-described flow battery system, the transformer is a phase-shifting transformer.

Preferably, in the above-mentioned flow battery system, the ac terminal of the power electronic converter is connected to the secondary winding of the phase-shifting transformer, and the number of the secondary windings of the phase-shifting transformer is not less than the number of the battery clusters.

Preferably, in the above flow battery system, the phase-shifting transformer is used to reduce current harmonics on the high-voltage side of the transformer and improve the power quality of the flow system.

Preferably, in the above flow battery system, the flow battery system further includes a switch cabinet, and the switch cabinet is connected to the transformer.

The application provides a flow battery system, which comprises a plurality of battery tanks and a plurality of groups of battery stacks, wherein each battery tank corresponds to one group of battery stacks, and each flow battery stack in the same group of battery stacks is connected with the battery tank corresponding to the group of battery stacks, wherein each flow battery stack in the same group of battery stacks belongs to different battery clusters, and the flow battery stacks in the same battery cluster are sequentially connected in series; the flow battery system takes the battery cluster as an energy unit and exchanges energy with the outside. The beneficial effect of this application lies in: through establishing ties with the redox flow battery that different battery jar corresponds, showing the voltage class that promotes the redox flow battery system, just can greatly promote redox flow battery system capacity under the same current, reduced the big problem of battery pile series efficiency loss among the prior art simultaneously, promote redox flow battery charge-discharge conversion efficiency.

The foregoing description is only an overview of the technical solutions of the present application, and the present application can be implemented according to the content of the description in order to make the technical means of the present application more clearly understood, and the following detailed description of the present application is given in order to make the above and other objects, features, and advantages of the present application more clearly understandable.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the application. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:

fig. 1 shows a schematic structural diagram of a flow battery system according to one embodiment of the present application;

fig. 2 shows a schematic structural diagram of a ferro-chromium flow battery system according to an embodiment of the present application;

FIG. 3 is a schematic diagram of a flow battery system according to the prior art;

Detailed Description

Exemplary embodiments of the present application will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

The utility model provides a conceive of, it is less to redox flow battery's among the prior art voltage, if establish ties the pile under the same battery jar, can lead to the electrochemistry liquid reflux, thereby produce the current situation of conversion efficiency loss, a redox flow battery system is proposed, this system establishes ties through the pile that corresponds different battery jars, show the voltage class that promotes redox flow battery system, just can greatly promote redox flow battery system capacity under the same current, the big problem of the pile series efficiency loss of same battery jar among the prior art has been reduced simultaneously, promote redox flow battery charge-discharge conversion efficiency.

Fig. 1 is a schematic structural diagram of a flow battery system according to an embodiment of the present application, where the flow battery system includes a plurality of battery cans and a plurality of sets of battery stacks, each battery can corresponds to a set of battery stacks, and each flow battery stack in the same set of battery stacks is commonly connected to the battery can corresponding to the set of battery stacks, where each flow battery stack in the same set of battery stacks belongs to a different battery cluster, and the flow battery stacks in the same battery cluster are sequentially connected in series; the flow battery system takes the battery cluster as an energy unit and exchanges energy with the outside.

The basic principle of the flow battery power generation is to realize charge exchange through the gain and loss electrons of the chemical oxidation-reduction reaction to form potential and current, and the iron-chromium flow battery is exemplified as follows:

fig. 2 shows a schematic structural diagram of an iron-chromium flow battery system according to an embodiment of the present application, and as can be seen from fig. 2, the flow battery mainly includes two battery cans and a battery stack, where one of the battery cans is a positive battery can and the other battery can is a negative battery can, and in practical situations, one battery can simultaneously provide liquid electron flow for a plurality of battery stacks, and a distinct feature of the flow battery is that the voltage is low, and generally the voltage of a single battery stack is below 200V.

The energy storage medium, namely electrolyte solution, is stored in an electrolyte battery jar outside the battery pair, the anode and the cathode in the battery are separated into two mutually independent chambers by an ion exchange membrane, namely an anode side chamber and a cathode side chamber, and the anode electrolyte and the cathode electrolyte are forced to circularly flow through respective reaction chambers by respective liquid feeding pumps when the battery works to participate in electrochemical reaction. Taking the anode as an example, the anode electrolyte solution is pumped into the anode side chamber, where the oxidation reaction takes place. When charging, the battery is externally connected with a power supply, electric energy is converted into chemical energy, and the chemical energy is stored in an electrolyte solution; when discharging, the battery is externally connected with a load, and chemical energy stored in the electrolyte solution is converted into electric energy for the load to use.

The type of the flow battery is not limited in the application, and may be any one of the prior art, or any one that satisfies the reaction system of the flow battery, such as an iron-chromium system flow battery, an iron-titanium system flow battery, an all-vanadium system flow battery, a vanadium-bromine system flow battery, a vanadium-cadmium system flow battery, an iron-vanadium system flow battery, a sodium polysulfide-bromine system flow battery, and the like.

Fig. 3 is a schematic diagram showing a circuit structure of a flow battery system according to the prior art, and as can be seen from fig. 3, a battery tank bus bar is connected with a plurality of flow battery stacks, and electrolyte is supplied to each flow battery stack, in the flow battery system shown in fig. 3, the relationship of each flow battery stack is a parallel relationship, and such a connection relationship has a problem that the voltage of the flow battery is small, generally below 200V, and the capacity of the flow battery system is small under the same current; and under the condition of large current, the working efficiency of the flow battery system is relatively low. For such a situation, in the prior art, the flow cell stacks are connected in series to increase the voltage of the flow cell, but this method may cause the electrochemical liquid to flow back, thereby causing the current situation of loss of conversion efficiency; in addition, in the method, all the cell stacks under the same cell tank are not isolated, and the alternating current side finally converges to one point, so that the converters corresponding to different cell stacks cannot be directly connected in parallel, and generally need to be connected in parallel through high common-mode impedance to reduce the common-mode current of a loop. Common high-impedance modes include isolation (including power frequency isolation and high-frequency isolation) or common-mode inductance, and the reason for adopting high-impedance parallel connection is that power electronic converters are all at common-mode voltage, if the common-mode impedance is small, common-mode circulating current can be formed, so that extra loss is generated, the conversion efficiency is influenced, and the normal operation of various devices is influenced due to serious electromagnetic interference.

In view of the above situation, the present application provides a flow battery system, a schematic circuit structure diagram of which is shown in fig. 1, the flow battery system includes a plurality of battery tanks and a plurality of sets of battery stacks, each battery tank corresponds to one set of battery stack, and each flow battery stack in the same set of battery stacks is connected to the battery tank corresponding to the set of battery stacks, wherein each flow battery stack in the same set of battery stacks belongs to different battery clusters, and the flow battery stacks in the same battery cluster are connected in series in sequence; the flow battery system takes the battery cluster as an energy unit and exchanges energy with the outside.

For convenience of explanation, in the flow battery system of the present application, a group number and a cluster number may be provided for each flow battery stack.

The flow battery system comprises a plurality of battery tanks, namely a 1# tank, a 2# tank and a M # tank; each battery tank corresponds to a group of battery stacks, each group of battery stacks comprises a plurality of flow battery stacks, and for example, a 1-1# flow battery stack, a 1-2# flow battery stack and an M-N # flow battery stack are connected with a bus bar of the 1# tank; wherein M and N are both positive integers. Flow battery stacks corresponding to different battery tanks form a battery cluster, and in the battery cluster, the positions of the flow battery stacks are in series relation, such as a 1-1# flow battery stack, a 2-1# flow battery stack and a flow battery stack up to M-1# flow battery stack form a first battery cluster, and a 1-2# flow battery stack, a 2-2# flow battery stack and a flow battery stack up to M-2# flow battery stack form a second battery cluster.

In the application, the connection relationship between the battery clusters is not limited, and the flow battery system preferably uses the battery clusters as energy units to exchange energy with the outside.

As can be seen from the flow system shown in FIG. 1, the flow batteries corresponding to different battery tanks are connected in series, so that the voltage level of the flow battery system is remarkably improved, the capacity of the flow battery system can be greatly improved under the same current, the problem of high loss of series efficiency of a battery stack in the prior art is solved, and the charge-discharge conversion efficiency of the flow battery is improved.

In one embodiment of the present application, the number of flow cell stacks in each stack is the same in the above-described flow cell system.

In the application, the number of the flow cell stacks in each group of the cell stacks can be different or the same, and the application recommends that the number of the flow cell stacks in each group of the cell stacks is the same as a preferred scheme, so that the number of the flow cell stacks in each cell cluster is the same, and the flow cell stacks are more convenient to use, such as adjustment of the voltage of the flow cell and conversion of direct current and alternating current.

In an embodiment of the present application, in the flow battery system, the flow battery system further includes a plurality of power electronic converters in one-to-one correspondence with the battery clusters, and each battery cluster is connected to a dc terminal of one power electronic converter.

The output end of the flow battery system can be directly connected with electric equipment, and electric energy output by the flow battery can be converted into a required electric energy form. As in the present embodiment, the flow battery system further includes a plurality of power electronic converters in one-to-one correspondence with the battery clusters, the power electronic converters include, but are not limited to, a dc chopper, an inverter, and the like, and each battery cluster is connected to a dc terminal of one power electronic converter. In the application, the electric energy output by the flow battery is in the form of direct current, and can be converted by a power electronic converter, for example, a direct current chopper is adopted to convert fixed direct current electric energy into adjustable direct current electric energy, and for example, an inverter is adopted to convert the direct current electric energy into alternating current electric energy.

In an embodiment of the present application, in the above-mentioned flow battery system, the power electronic converter is a DC/AC converter, or a combination of a DC/DC converter and a DC/AC converter, that is, the converter with an input terminal being a DC terminal and an output terminal being an AC terminal, and the power electronic converter converts DC electric energy into AC electric energy.

The application recommends a single-stage DC/AC converter as a preferable scheme, and under the flow battery system of the application, the single-stage DC/AC converter is used, the direct-current voltage is higher than that of the prior art, and the control stability is also higher.

In an embodiment of the present application, in the flow battery system described above, the flow battery system further includes a transformer, and the ac terminal of the power electronic converter is connected to the transformer. In practical application, a household voltage of 220V and a production voltage of 380V are the most commonly used voltages, and the ac power output from the ac terminal of the power electronic converter can be converted into 220V or 380V power through a transformer.

In addition, in an embodiment of the present application, the flow battery system may be further connected to a power grid for performing Peak load shifting (Peak cut) of a load of the power grid. The peak clipping and valley filling are measures for adjusting the power load, the load peak and valley value of the power system is larger and larger along with the increase of the power consumption, and the capacity of the power transmission and distribution line is simply upgraded and expanded, so that the cost is high and the efficiency is low. And the energy storage battery system is adopted to carry out peak clipping and valley filling on the power distribution network, so that great economic benefit is realized while the peak-valley difference is reduced.

In the prior art, as shown in fig. 3, each power electronic converter is connected with a transformer, so that the number of flow battery stacks is large, and therefore, the number of required transformers is also large, which results in a large overall volume and large floor area of a flow battery system.

In the present application, a plurality of power electronic converters may be connected to a transformer at their ac terminals, and a phase-shifting transformer is preferred as the transformer, as shown in fig. 1.

The phase-shifting transformer is one kind of rectifier transformer, which is the power transformer of rectifier equipment, and the rectifier equipment features that AC power is input to the input side and DC power is output to the output side via the rectifier.

The single-phase conduction of the rectifier equipment causes the distortion of the alternating magnetic field waveform of the rectifier transformer, and the magnitude of the distortion is determined by the proportion of the direct-current capacity to the power grid capacity, the frequency of harmonic current flowing into the power grid and the harmonic frequency.

In an embodiment of the present application, in the above-mentioned flow battery system, the ac terminal of the power electronic converter is connected to the secondary winding of the phase-shifting transformer, and the number of the secondary winding of the phase-shifting transformer is not less than the number of the battery clusters.

The output end of the power electronic converter is connected with the input end of the phase-shifting transformer, specifically, the output end of the power electronic converter is connected with the secondary side winding of the phase-shifting transformer, the number of the secondary side windings of the phase-shifting transformer is not less than the number of the battery clusters, the alternating current end of the power electronic converter corresponding to each battery cluster is respectively connected to one secondary side winding, namely, when the number of the secondary side windings of the phase-shifting transformer is equal to the number of the battery clusters, each battery cluster is ensured to be connected to one secondary side winding; when the number of secondary side windings of the phase-shifting transformer is larger than the number of battery clusters, disaster tolerance can be performed, so-called disaster tolerance, which means that two or more sets of systems with the same function are established in different places far away from each other, and health state monitoring and function switching can be performed between the two sets of systems. In the embodiment, if one secondary side winding is damaged, the alternating current end of the power electronic converter corresponding to the damaged secondary side winding can be switched to the rest secondary side winding, so that the maintenance is simple and the equipment does not need to be frequently replaced when a fault occurs.

One of the effective ways to suppress harmonics is by shifting the phase of the high-voltage side of the rectifier transformer, which essentially eliminates the lower harmonics with larger amplitudes. That is, in the present application, the phase-shifting transformer can be used to reduce the current harmonics on the high-voltage side of the transformer and improve the power quality of the flow system.

In an embodiment of the present application, in the above-mentioned flow battery system, the flow battery system further includes a switch cabinet, the switch cabinet is connected to the transformer, and a switch is installed in the switch cabinet and is used for controlling the flow battery to be incorporated into an electric network for a user connected to the electric network. That is to say, the flow battery system in the present application can be a grid-connected energy storage system, for example, can be electrically connected to a local power grid, and becomes a part of the grid-connected energy storage system.

In summary, the present application provides a flow battery system, which includes a plurality of battery cans and a plurality of sets of battery stacks, each battery can corresponds to one set of battery stack, each flow battery stack in the same set of battery stacks is connected to the battery can corresponding to the set of battery stacks, wherein each flow battery stack in the same set of battery stacks belongs to different battery clusters, and the flow battery stacks in the same battery cluster are sequentially connected in series; the flow battery system takes the battery cluster as an energy unit and exchanges energy with the outside. The beneficial effect of this application lies in: through establishing ties with the redox flow battery that different battery jar corresponds, showing the voltage class that promotes the redox flow battery system, just can greatly promote redox flow battery system capacity under the same current, reduced the big problem of battery pile series efficiency loss among the prior art simultaneously, promote redox flow battery charge-discharge conversion efficiency.

It should be noted that:

in the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the application may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

Similarly, it should be appreciated that in the foregoing description of exemplary embodiments of the application, various features of the application are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the application and aiding in the understanding of one or more of the various application aspects. However, the disclosed method should not be interpreted as reflecting an intention that: this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains. Rather, as the following claims reflect, application is directed to less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this application.

Furthermore, those skilled in the art will appreciate that while some embodiments described herein include some features included in other embodiments, rather than other features, combinations of features of different embodiments are meant to be within the scope of the application and form different embodiments. For example, in the following claims, any of the claimed embodiments may be used in any combination.

It should be noted that the above-mentioned embodiments illustrate rather than limit the application, and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The application may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by one and the same item of hardware. The usage of the words first, second and third, etcetera do not indicate any ordering. These words may be interpreted as names.