A liquid flow battery stack

Abstract

The present invention proposes a liquid flow battery stack, which includes a left end plate, a left liquid guide plate, a right liquid guide plate, a right end plate stacked in sequence, and single cells located between the left liquid guide plate and the right liquid guide plate, which are separated from left to right by bipolar plates. By increasing the number of common pipelines in a single stack, and the positive or negative electrodes of adjacent single cells are not connected to the same positive or negative electrode electrolyte common pipeline, the length of the common pipeline between the single cells in the stack that are supplied with liquid in parallel is increased. The above-mentioned left liquid guide plate and right liquid guide plate connect the two adjacent common pipelines within the liquid guide plate, thereby forming a whole common pipeline, which is connected to the electrolyte inlet and outlet on the end plate. The number of inlets and outlets of the multiple positive and negative electrode electrolyte common pipelines opened on the end plate is reduced to 4, which reduces the processing requirements and cost of the end plate and simplifies the setting of the external pipelines of the stack. The extended common pipeline length can reduce the leakage current of the stack and improve the efficiency and reliability of the stack.

Description

Technical Field

[0001] The present invention relates to a flow battery stack, and in particular to a stack interior and a liquid guide plate structure for conducting electrolyte flow in the stack. Background Art

[0002] With the increasing share of renewable energy in the power grid in recent years, a trend has emerged of replacing traditional fossil fuels. However, renewable energy suffers from unstable and intermittent power generation, resulting in poor power quality. Such large-scale grid integration would inevitably have a significant impact on the power grid. A new type of energy storage device can address this issue. Its peak-load shifting and frequency-shaving capabilities can significantly improve the quality of renewable energy power, increase grid access time, and reduce wind and solar curtailment. Energy storage technologies can be categorized into physical energy storage, such as pumped hydro and flywheel storage, and chemical energy storage, primarily based on batteries. Due to the high environmental requirements of physical energy storage, chemical energy storage is the primary method. Flow batteries, as an emerging electrochemical energy storage device, have seen significant development in recent years. Their features include deep charge and discharge capabilities, independent power and capacity design, high safety, no fire or explosion hazards, long lifespan, and a cost-effective lifecycle, making them ideal for large-scale energy storage applications.

[0003] A flow battery system primarily consists of batteries, electrolyte storage tanks, electrolyte, and piping systems. Batteries are the most critical component in a flow battery system, determining system performance and reliability and serving as the key location for chemical reactions. The stack is the most important power device, so higher power density translates to better stack output, but this also comes with a decrease in voltage efficiency. Developing high-power-density, high-performance stacks requires increasing the stack's operating current density by controlling cell polarization, or by utilizing ultra-thin cell technology to connect more cells in series per unit volume while maintaining efficiency, thereby increasing the stack's overall operating voltage. Flow batteries generate leakage current due to their electrolyte supply method. This current does not flow through the cells but is instead consumed by the external electrolyte, resulting in additional losses. Generally speaking, leakage current is primarily determined by the number of cells, the current draw, and the resistance of the electrolyte supply mains within the stack and the electrolyte distribution lines within the electrode frame. For high-power stacks, the number of cells connected in series can often reach 50-100. If the stack structure is not improved, for example, by using a split stack structure to reduce the number of battery cells in a single stack, the coulombic efficiency of the stack will be significantly reduced. In severe cases, it may cause the electrolyte to overheat, damaging the stack and the electrolyte pipeline. In order to avoid too many battery cells in series, some stack structures have several groups of electrolyte inlets and outlets on the liquid inlet end plate of the stack. The stack is divided into the same number of battery cells, and the electrolyte is supplied by the several groups of electrolyte inlets and outlets on the above-mentioned liquid inlet end plate. In this way, the situation where too many batteries in the stack share a common electrolyte supply main line is interrupted, resulting in excessive leakage current. However, the processing of the liquid inlet end plate of the stack is relatively complicated, and the setting of more valves has to increase the area of ​​the end plate, resulting in additional cost losses. Summary of the Invention

[0004] In order to reduce leakage loss in the above-mentioned battery stack, improve the efficiency and reliability of the battery stack, and reduce the processing requirements and costs of the end plates, the present invention proposes a liquid flow battery stack.

[0005] The stack includes a left end plate, a left liquid guide plate, a right liquid guide plate, a right end plate stacked in sequence, and single cells located between the left liquid guide plate and the right liquid guide plate and separated from left to right by bipolar plates.

[0006] The above-mentioned single cell comprises a positive electrode located in the middle through hole of the positive electrode frame, an ion conductive membrane, and a negative electrode located in the middle through hole of the negative electrode frame, which are stacked in sequence from left to right;

[0007] The number of cells separated by bipolar plates is M, where M is an integer greater than or equal to 4;

[0008] N through-holes serving as positive electrode electrolyte inlets, N through-holes serving as positive electrode electrolyte outlets, N through-holes serving as negative electrode electrolyte inlets, and N through-holes serving as negative electrode electrolyte outlets are respectively provided at corresponding positions on the bipolar plate; the number of positive electrode electrolyte inlets, positive electrode electrolyte outlets, negative electrode electrolyte inlets, and negative electrode electrolyte outlets on the bipolar plate are all the same; if M is an even number, N is 2 to M / 2; if M is an odd number, N is 2 to (M+1) / 2;

[0009] N is an odd number, and at the corresponding positions of the through holes on the bipolar plates, N-1 blind holes as the positive electrode electrolyte inlet, N-1 blind holes as the positive electrode electrolyte outlet, N-1 blind holes as the negative electrode electrolyte inlet, and N-1 blind holes as the negative electrode electrolyte outlet are opened on the right liquid guide plate; 1 through hole as the positive electrode electrolyte inlet and N-1 blind holes as the positive electrode electrolyte inlet, 1 through hole as the positive electrode electrolyte outlet and N-1 blind holes as the positive electrode electrolyte outlet, 1 through hole as the negative electrode electrolyte inlet and N-1 blind holes as the negative electrode electrolyte inlet, 1 through hole as the negative electrode electrolyte outlet and N-1 blind holes as the negative electrode electrolyte outlet are opened on the left liquid guide plate;

[0010] Alternatively, N is an even number, and at the corresponding positions of the through holes on the bipolar plates, N blind holes as the positive electrode electrolyte inlet, N blind holes as the positive electrode electrolyte outlet, N blind holes as the negative electrode electrolyte inlet, and N blind holes as the negative electrode electrolyte outlet are opened on the right liquid guide plate; the left liquid guide plate is provided with 1 through hole as the positive electrode electrolyte inlet and N-2 blind holes as the positive electrode electrolyte inlet, 1 through hole as the positive electrode electrolyte outlet and N-2 blind holes as the positive electrode electrolyte outlet, 1 through hole as the negative electrode electrolyte inlet and N-2 blind holes as the negative electrode electrolyte inlet, 1 through hole as the negative electrode electrolyte outlet, and N-2 blind holes as the negative electrode electrolyte outlet;

[0011] At the corresponding position of the through hole on the left liquid guide plate, a through hole as the positive electrode electrolyte inlet, a through hole as the positive electrode electrolyte outlet, a through hole as the cathode electrolyte inlet, and a through hole as the negative electrode electrolyte outlet are opened on the left end plate;

[0012] From left to right, the left liquid guide plate and the positive electrode electrolyte inlet at the corresponding position on the bipolar plate are connected in series in sequence to form a total of N positive electrode electrolyte inlet channels; from left to right, the end plate and the positive electrode electrolyte outlet at the corresponding position on the bipolar plate are connected in series in sequence to form a total of N positive electrode electrolyte outlet channels; from left to right, the end plate and the negative electrode electrolyte inlet at the corresponding position on the bipolar plate are connected in series in sequence to form a total of N negative electrode electrolyte inlet channels; from left to right, the end plate and the negative electrode electrolyte outlet at the corresponding position on the bipolar plate are connected in series in sequence to form a total of N negative electrode electrolyte outlet channels;

[0013] The left side of the channel is the head and the right side is the tail;

[0014] The N positive electrode electrolyte inlet channels on the left liquid guide plate and the bipolar plate are connected in pairs in sequence through the channels between the blind holes inside the left liquid guide plate and the right liquid guide plate body, and in pairs in sequence to form a common channel with one end closed and the other end open. The open end of the common channel is connected to the positive electrode electrolyte inlet channel of the left end plate;

[0015] The N positive electrode electrolyte outlet channels on the left liquid guide plate and the bipolar plate are connected in pairs and in pairs respectively through the channels between the blind holes inside the left liquid guide plate and the right liquid guide plate to form a common channel with one end closed and the other end open. The open end of the common channel is connected to the positive electrode electrolyte outlet channel of the left end plate.

[0016] The N negative electrode electrolyte inlet channels on the left liquid guide plate and the bipolar plate are connected in pairs in sequence through the channels between the blind holes inside the left liquid guide plate and the right liquid guide plate body, and in pairs in sequence, to form a common channel with one end closed and the other end open, and the open end of the common channel is connected to the negative electrode electrolyte inlet channel of the left end plate;

[0017] The N negative electrode electrolyte outlet channels on the left liquid guide plate and the bipolar plate are connected in pairs in sequence through the channels between the blind holes inside the left liquid guide plate and the right liquid guide plate bodies, and in pairs in sequence, to form a common channel with one end closed and the other end open, and the open end of the common channel is connected to the negative electrode electrolyte outlet channel of the left end plate;

[0018] From left to right, one end of the positive electrode in the 1st to Mth single cells is connected to one channel of the N positive electrolyte inlet channels, and the other end is connected to one channel of the N positive electrolyte outlet channels; and the positive electrodes of adjacent single cells are respectively connected to different channels of the N positive electrolyte inlet channels, and the positive electrodes of adjacent single cells are respectively connected to different channels of the N positive electrolyte outlet channels; and the other end of the single cell connected to a positive electrolyte inlet channel is connected to a positive electrolyte outlet channel;

[0019] From left to right, one end of the negative electrode in the 1st to Mth single cells is connected to one channel of the N negative electrode electrolyte inlet channels, and the other end is connected to one channel of the N negative electrode electrolyte outlet channels; and the negative electrodes of adjacent single cells are respectively connected to different channels of the N negative electrode electrolyte inlet channels, and the negative electrodes of adjacent single cells are respectively connected to different channels of the N negative electrode electrolyte outlet channels; and the other end of the single cell connected to a negative electrode electrolyte inlet channel is connected to a negative electrode electrolyte outlet channel.

[0020] The structure of the flow battery stack proposed by the present invention can also be: comprising a left end plate, a left liquid guide plate, a right liquid guide plate, a right end plate stacked in sequence, and single cells located between the left liquid guide plate and the right liquid guide plate and separated from left to right by bipolar plates.

[0021] The single cell comprises a positive electrode located in a through hole in the middle of a positive electrode frame, an ion conducting membrane, and a negative electrode located in a through hole in the middle of a negative electrode frame, which are stacked in sequence from left to right.

[0022] The number of cells separated by bipolar plates is M*N;

[0023] N through-holes serving as positive electrode electrolyte inlets, N through-holes serving as positive electrode electrolyte outlets, N through-holes serving as negative electrode electrolyte inlets, and N through-holes serving as negative electrode electrolyte outlets are respectively provided at corresponding positions on the bipolar plate; the number of positive electrode electrolyte inlets, positive electrode electrolyte outlets, negative electrode electrolyte inlets, and negative electrode electrolyte outlets on the bipolar plate are all the same;

[0024] N is an odd number, and at the corresponding positions of the through holes on the bipolar plates, N-1 blind holes as the positive electrode electrolyte inlet, N-1 blind holes as the positive electrode electrolyte outlet, N-1 blind holes as the negative electrode electrolyte inlet, and N-1 blind holes as the negative electrode electrolyte outlet are opened on the right liquid guide plate; 1 through hole as the positive electrode electrolyte inlet and N-1 blind holes as the positive electrode electrolyte inlet, 1 through hole as the positive electrode electrolyte outlet and N-1 blind holes as the positive electrode electrolyte outlet, 1 through hole as the negative electrode electrolyte inlet and N-1 blind holes as the negative electrode electrolyte inlet, 1 through hole as the negative electrode electrolyte outlet, and N-1 blind holes as the negative electrode electrolyte outlet are opened on the left liquid guide plate;

[0025] Alternatively, N is an even number, and at corresponding positions of the through holes on the bipolar plates, N blind holes as positive electrode electrolyte inlets, N blind holes as positive electrode electrolyte outlets, N blind holes as negative electrode electrolyte inlets, and N blind holes as negative electrode electrolyte outlets are provided on the right liquid guide plate; 1 through hole as positive electrode electrolyte inlet and N-2 blind holes as positive electrode electrolyte inlets, 1 through hole as positive electrode electrolyte outlet and N-2 blind holes as positive electrode electrolyte outlets, 1 through hole as negative electrode electrolyte inlet and N-2 blind holes as negative electrode electrolyte inlet, 1 through hole as negative electrode electrolyte outlet, and N-2 blind holes as negative electrode electrolyte outlets are provided on the left liquid guide plate;

[0026] At the corresponding position of the through hole on the left liquid guide plate, a through hole as the positive electrode electrolyte inlet, a through hole as the positive electrode electrolyte outlet, a through hole as the cathode electrolyte inlet, and a through hole as the negative electrode electrolyte outlet are opened on the left end plate;

[0027] From left to right, the left liquid guide plate and the positive electrode electrolyte inlet at the corresponding position on the bipolar plate are connected in series in sequence to form a total of N positive electrode electrolyte inlet channels; from left to right, the end plate and the positive electrode electrolyte outlet at the corresponding position on the bipolar plate are connected in series in sequence to form a total of N positive electrode electrolyte outlet channels; from left to right, the end plate and the negative electrode electrolyte inlet at the corresponding position on the bipolar plate are connected in series in sequence to form a total of N negative electrode electrolyte inlet channels; from left to right, the end plate and the negative electrode electrolyte outlet at the corresponding position on the bipolar plate are connected in series in sequence to form a total of N negative electrode electrolyte outlet channels;

[0028] The left side of the channel is the head and the right side is the tail;

[0029] The N positive electrode electrolyte inlet channels on the left liquid guide plate and the bipolar plate are connected in pairs in sequence through the channels between the blind holes inside the left liquid guide plate and the right liquid guide plate body, and in pairs in sequence to form a common channel with one end closed and the other end open. The open end of the common channel is connected to the positive electrode electrolyte inlet channel of the left end plate;

[0030] The N positive electrode electrolyte outlet channels on the left liquid guide plate and the bipolar plate are connected in pairs and in pairs respectively through the channels between the blind holes inside the left liquid guide plate and the right liquid guide plate to form a common channel with one end closed and the other end open. The open end of the common channel is connected to the positive electrode electrolyte outlet channel of the left end plate.

[0031] The N negative electrode electrolyte inlet channels on the left liquid guide plate and the bipolar plate are connected in pairs in sequence through the channels between the blind holes inside the left liquid guide plate and the right liquid guide plate body, and in pairs in sequence, to form a common channel with one end closed and the other end open, and the open end of the common channel is connected to the negative electrode electrolyte inlet channel of the left end plate;

[0032] The N negative electrode electrolyte outlet channels on the left liquid guide plate and the bipolar plate are connected in pairs in sequence through the channels between the blind holes inside the left liquid guide plate and the right liquid guide plate bodies, and in pairs in sequence, to form a common channel with one end closed and the other end open, and the open end of the common channel is connected to the negative electrode electrolyte outlet channel of the left end plate;

[0033] From left to right, one end of the positive electrode in the Kth cell and the N+Kth cell is connected to the Kth channel of the N positive electrode electrolyte inlet channels, and the other end is connected to the Kth channel of the N positive electrode electrolyte outlet channels; from left to right, one end of the negative electrode in the Kth cell and the N+Kth cell is connected to the Kth channel of the N negative electrode electrolyte inlet channels, and the other end is connected to the Kth channel of the N negative electrode electrolyte outlet channels; K represents an integer from 1 to N.

[0034] In the above-mentioned fuel cell stack, N positive electrolyte inlet channels and N positive electrolyte outlet channels are respectively connected to the positive electrolyte storage tank outside the fuel cell stack; N negative electrolyte inlet channels and N negative electrolyte outlet channels are respectively connected to the negative electrolyte storage tank outside the fuel cell stack.

[0035] M is an integer greater than or equal to 5; N is an integer greater than or equal to 3.

[0036] The present invention has the following advantages:

[0037] 1. The flow battery stack proposed in this invention increases the number of common electrolyte conduits, which originally had only one. The positive or negative electrodes of adjacent cells are not connected to the same common electrolyte conduit, increasing the resistance of the common electrolyte conduit and reducing leakage current. Furthermore, the common conduit resistance can be flexibly designed based on the number of cells in the stack to achieve the purpose of regulating leakage current.

[0038] 2. In the flow battery stack proposed by this invention, the liquid guide plate connects two adjacent common pipelines within the liquid guide plate, forming a single common pipeline that connects to the electrolyte inlet and outlet on the end plate. This reduces the number of inlets and outlets for the multiple positive and negative electrolyte common pipelines on the end plate to four, reducing the processing requirements and costs of the end plate and simplifying the external pipeline configuration of the battery stack. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A flow battery stack proposed by the present invention;

[0040] 1. A left end plate having a positive electrolyte inlet, a positive electrolyte outlet, a negative electrolyte inlet, and a negative electrolyte outlet; 2. A left liquid guide plate; 3. A bipolar plate; 4. Positive electrode; 5. Positive electrode frame connected to the first positive electrolyte inlet channel and the first positive electrolyte outlet channel; 6. Ion conduction membrane; 7. Negative electrode; 8. Negative electrode frame connected to the first negative electrolyte inlet channel and the first negative electrolyte outlet channel; 9. Positive electrode frame connected to the second positive electrolyte inlet channel and the second positive electrolyte outlet channel; 10. Negative electrode frame connected to the second negative electrolyte inlet channel and the second negative electrolyte outlet channel; 11. Positive electrode frame connected to the third positive electrolyte inlet channel and the third positive electrolyte outlet channel; 12. Negative electrode frame connected to the third negative electrolyte inlet channel and the third negative electrolyte outlet channel; 13. Right liquid guide plate; 14. Right end plate.

[0041] Figure 2 for Figure 1 The left liquid guide plate of the fuel cell stack;

[0042] Among them, 15, 18, 21, and 24 are respectively the through holes serving as the positive electrolyte inlet, the positive electrolyte outlet, the negative electrolyte inlet, and the negative electrolyte outlet on the left end plate 1, which are connected to the corresponding ones. 16 and 17 are respectively blind holes connected to the second positive electrolyte inlet channel and the third positive electrolyte inlet channel, and the two blind holes are connected in the left liquid guide plate 2; 19 and 20 are respectively blind holes connected to the second positive electrolyte outlet channel and the third positive electrolyte outlet channel, and the two blind holes are connected in the left liquid guide plate 2. 22 and 23 are blind holes connected to the second negative electrode electrolyte inlet channel and the third negative electrode electrolyte inlet channel, respectively, and the two blind holes are connected in the left liquid guide plate 2; 25 and 26 are blind holes connected to the second negative electrode electrolyte outlet channel and the third negative electrode electrolyte outlet channel, respectively, and the two blind holes are connected in the left liquid guide plate 2.

[0043] Figure 3 for Figure 1 The right liquid guide plate of the battery stack described in the figure:

[0044] Among them, 27 and 28 are blind holes connected to the first positive electrode electrolyte inlet channel and the second positive electrode electrolyte inlet channel, respectively, and the two blind holes are connected in the right liquid guide plate 13; 29 and 30 are blind holes connected to the first positive electrode electrolyte outlet channel and the second positive electrode electrolyte outlet channel, respectively, and the two blind holes are connected in the right liquid guide plate 13; 31 and 32 are blind holes connected to the first negative electrode electrolyte inlet channel and the second negative electrode electrolyte inlet channel, respectively, and the two blind holes are connected in the right liquid guide plate 13; 33 and 34 are blind holes connected to the first negative electrode electrolyte outlet channel and the second negative electrode electrolyte outlet channel, respectively, and the two blind holes are connected in the right liquid guide plate 13. DETAILED DESCRIPTION

[0045] Example:

[0046] A flow battery stack such as Figure 1 The stack includes a left end plate 1, a left liquid guide plate 2, a right liquid guide plate 13, and a right end plate 14, which are stacked in sequence. The cells are located between the left and right liquid guide plates 2 and 13 and separated from left to right by bipolar plates 3. The cells include a positive electrode 4 located in a through-hole in the center of the positive electrode frame, an ion conductive membrane 6, and a negative electrode 7 located in a through-hole in the center of the negative electrode frame, which are stacked in sequence from left to right.

[0047] The number of cells separated by bipolar plates in the stack is 10*3=30 (M=10, N=3);

[0048] Three through holes serving as the positive electrode electrolyte inlet, three through holes serving as the positive electrode electrolyte outlet, three through holes serving as the negative electrode electrolyte inlet, and three through holes serving as the negative electrode electrolyte outlet are respectively provided at corresponding positions on the bipolar plate 3 .

[0049] Because N=3 is an odd number, at the corresponding positions of the through holes on the bipolar plate 6, two blind holes serving as the positive electrolyte inlet are opened on the right liquid guide plate 13, namely a blind hole 27 connected to the first positive electrolyte inlet channel and a blind hole 28 connected to the second positive electrolyte inlet channel; two blind holes serving as the positive electrolyte outlet, namely a blind hole 29 connected to the first positive electrolyte outlet channel and a blind hole 30 connected to the second positive electrolyte outlet channel; two blind holes serving as the negative electrolyte inlet, namely a blind hole 31 connected to the first negative electrolyte inlet channel and a blind hole 32 connected to the second negative electrolyte inlet channel; and two blind holes serving as the negative electrolyte outlet, namely a blind hole 33 connected to the first negative electrolyte outlet channel and a blind hole 34 connected to the second negative electrolyte outlet channel.

[0050] The left liquid guide plate 2 is provided with a through hole 15 serving as a positive electrolyte inlet and two blind holes serving as positive electrolyte inlets, namely a blind hole 16 communicating with the second positive electrolyte inlet channel and a blind hole 17 communicating with the third positive electrolyte inlet channel; a through hole 18 serving as a positive electrolyte outlet and two blind holes serving as positive electrolyte outlets, namely a blind hole 19 communicating with the second positive electrolyte outlet channel and a blind hole 20 communicating with the third positive electrolyte outlet channel; One through hole 21 serving as the negative electrode electrolyte inlet and two blind holes serving as the negative electrode electrolyte inlet, which are respectively a blind hole 22 connected to the second negative electrode electrolyte inlet channel and a blind hole 23 connected to the third negative electrode electrolyte inlet channel; one through hole 24 serving as the negative electrode electrolyte outlet and two blind holes serving as the negative electrode electrolyte outlet, which are respectively a blind hole 25 connected to the second negative electrode electrolyte outlet channel and a blind hole 26 connected to the third negative electrode electrolyte outlet channel.

[0051] At the corresponding positions of the through holes 15, 18, 21 and 24 on the left liquid guide plate 2, a through hole as the positive electrode electrolyte inlet, a through hole as the positive electrode electrolyte outlet, a through hole as the negative electrode electrolyte inlet, and a through hole as the negative electrode electrolyte outlet are opened on the left end plate;

[0052] From left to right, the positive electrolyte inlets at corresponding positions on the left liquid guide plate 2 and the bipolar plate 3 are connected in series, forming a total of three positive electrolyte inlet channels. From the outside to the inside along the length of the electrode frame, there are the first positive electrolyte inlet channel, the second positive electrolyte inlet channel, and the third positive electrolyte inlet channel. From left to right, the positive electrolyte outlets at corresponding positions on the end plate and the bipolar plate are connected in series, forming a total of three positive electrolyte outlet channels. From the outside to the inside along the length of the electrode frame, there are the first positive electrolyte outlet channel, the second positive electrolyte outlet channel, and the third positive electrolyte outlet channel. From left to right, the negative electrolyte inlets at corresponding positions on the end plate and the bipolar plate are connected in series, forming a total of three negative electrolyte inlet channels. From the outside of the electrode frame to the inside, the first negative electrolyte inlet channel, the second negative electrolyte inlet channel, and the third negative electrolyte inlet channel are arranged in sequence. From left to right, the corresponding negative electrolyte outlets on the end plates and bipolar plates are connected in series, forming a total of three negative electrolyte outlet channels. From the outside of the electrode frame to the inside, the first negative electrolyte outlet channel, the second negative electrolyte outlet channel, and the third negative electrolyte outlet channel are arranged in sequence.

[0053] The left side of the channel is the beginning and the right side is the end.

[0054] The channels between the blind holes inside the left liquid guide plate 2 are connected in pairs in sequence: the blind holes 16 and 17 connected to the second positive electrode electrolyte inlet channel and the third positive electrode electrolyte inlet channel are connected in the left liquid guide plate 2; the blind holes 19 and 20 connected to the second positive electrode electrolyte outlet channel and the third positive electrode electrolyte outlet channel are connected in the left liquid guide plate 2; the blind holes 22 and 23 connected to the second negative electrode electrolyte inlet channel and the third negative electrode electrolyte inlet channel are connected in the left liquid guide plate 2; the blind holes 25 and 26 connected to the second negative electrode electrolyte outlet channel and the third negative electrode electrolyte outlet channel are connected in the left liquid guide plate 2.

[0055] The channels between the blind holes inside the right liquid guide plate 13 are connected in pairs in sequence: the blind holes 27 and 28 connected to the first positive electrode electrolyte inlet channel and the second positive electrode electrolyte inlet channel are connected in the right liquid guide plate 13; the blind holes 29 and 30 connected to the first positive electrode electrolyte outlet channel and the second positive electrode electrolyte outlet channel are connected in the right liquid guide plate 13; the blind holes 31 and 32 connected to the first negative electrode electrolyte inlet channel and the second negative electrode electrolyte inlet channel are connected in the right liquid guide plate 13; the blind holes 33 and 34 connected to the first negative electrode electrolyte outlet channel and the second negative electrode electrolyte outlet channel are connected in the right liquid guide plate 13.

[0056] The three positive electrode electrolyte inlet channels on the left liquid guide plate 2 and the bipolar plate 3 are connected in pairs in sequence through the channels between the blind holes inside the left liquid guide plate 2 and the right liquid guide plate 13, and are connected in pairs in sequence to form a common channel with one end closed and the other end open. The open end of the common channel is connected to the positive electrode electrolyte inlet channel of the left end plate;

[0057] The three positive electrolyte outlet channels on the left liquid guide plate 2 and the bipolar plate 3 are connected in pairs and in pairs respectively through the channels between the blind holes inside the left liquid guide plate 2 and the right liquid guide plate 13 to form a common channel with one end closed and the other end open. The open end of the common channel is connected to the positive electrolyte outlet channel of the left end plate.

[0058] The three negative electrode electrolyte inlet channels on the left liquid guide plate 2 and the bipolar plate 3 are connected in pairs in sequence through the channels between the blind holes inside the left liquid guide plate 2 and the right liquid guide plate 13, and are connected in pairs in sequence to form a common channel with one end closed and the other end open. The open end of the common channel is connected to the negative electrode electrolyte inlet channel of the left end plate;

[0059] The three negative electrode electrolyte outlet channels on the left liquid guide plate 2 and the bipolar plate 3 are connected in pairs through the channels between the blind holes inside the left liquid guide plate and the right liquid guide plate, and in pairs, respectively, to form a common channel with one end closed and the other end open. The open end of the common channel is connected to the negative electrode electrolyte outlet channel of the left end plate;

[0060] From left to right, the 1st cell, the 4th cell, the 7th cell┉the 28th cell, a total of 10 cells, one end of the positive electrode is connected to the first of the three positive electrode electrolyte inlet channels, and the other end is connected to the first of the three positive electrode electrolyte outlet channels; from left to right, the 1st cell, the 4th cell, the 7th cell┉the 28th cell, a total of 10 cells, one end of the negative electrode is connected to the first of the three negative electrode electrolyte inlet channels, and the other end is connected to the first of the three negative electrode electrolyte outlet channels.

[0061] From left to right, the 2nd cell, the 5th cell, the 8th cell┉the 29th cell, a total of 10 cells, one end of the positive electrode is connected to the second channel of the three positive electrode electrolyte inlet channels, and the other end is connected to the second channel of the three positive electrode electrolyte outlet channels; from left to right, the 2nd cell, the 5th cell, the 8th cell┉the 29th cell, a total of 10 cells, one end of the negative electrode is connected to the second channel of the three negative electrode electrolyte inlet channels, and the other end is connected to the second channel of the three negative electrode electrolyte outlet channels.

[0062] From left to right, the 3rd cell, the 6th cell, the 9th cell┉the 30th cell, a total of 10 cells, one end of the positive electrode is connected to the third channel of the three positive electrode electrolyte inlet channels, and the other end is connected to the third channel of the three positive electrode electrolyte outlet channels; from left to right, the 3rd cell, the 6th cell, the 9th cell┉the 30th cell, a total of 10 cells, one end of the negative electrode is connected to the third channel of the three negative electrode electrolyte inlet channels, and the other end is connected to the third channel of the three negative electrode electrolyte outlet channels.

[0063] The three positive electrode electrolyte inlet channels and the three positive electrode electrolyte outlet channels of the fuel cell stack are respectively connected to the positive electrode electrolyte storage tank outside the fuel cell stack; the three negative electrode electrolyte inlet channels and the three negative electrode electrolyte outlet channels are respectively connected to the negative electrode electrolyte storage tank outside the fuel cell stack.

[0064] The positive electrode electrolyte is drawn out from the positive electrode electrolyte storage tank by a magnetic pump and pumped into the positive electrode electrolyte inlet of the left end plate 1, flowing into the positive electrode electrolyte inlet through-hole 15 of the left liquid guide plate 2, passing through the three positive electrode electrolyte inlet channels on the left liquid guide plate 2 and the bipolar plate 3, and in turn passing through the channels between the blind holes inside the left liquid guide plate 2 and the right liquid guide plate 13, which are connected in pairs and in pairs to form a common channel with one end closed and the other end open, and flows into the positive electrode in the positive electrode frame of the single cell to react, and then flows out from the three positive electrode electrolyte outlet channels on the left liquid guide plate 2 and the bipolar plate 3 through the channels between the blind holes inside the left liquid guide plate 2 and the right liquid guide plate 13, which are connected in pairs and in pairs to form a common channel with one end closed and the other end open, and flows out to the positive electrode outlet through-hole 18 on the left liquid guide plate 2, and passes through the left end plate 1 The positive electrode electrolyte outlet flows back to the positive electrode electrolyte storage tank.

[0065] The negative electrode electrolyte is drawn out from the negative electrode electrolyte storage tank by a magnetic pump and pumped into the negative electrode electrolyte inlet of the left end plate 1, flowing into the negative electrode electrolyte inlet through-hole 21 of the left liquid guide plate 2, passing through the three negative electrode electrolyte inlet channels on the left liquid guide plate 2 and the bipolar plate 3, and in turn passing through the channels between the blind holes inside the left liquid guide plate 2 and the right liquid guide plate 13, which are connected in pairs and in pairs to form a common channel with one end closed and the other end open, and flows into the negative electrode in the negative electrode frame of the single cell to react, and then flows out from the three negative electrode electrolyte outlet channels on the left liquid guide plate 2 and the bipolar plate 3 through the channels between the blind holes inside the left liquid guide plate 2 and the right liquid guide plate 13, which are connected in pairs and in pairs to form a common channel with one end closed and the other end open, and flows out to the negative electrode outlet through-hole 24 on the left liquid guide plate 2, and passes through the left end plate 1 The negative electrode electrolyte outlet flows back to the negative electrode electrolyte storage tank.

[0066] The flow battery stack using the present invention demonstrated a Coulombic efficiency of 98.6%, a voltage efficiency of 85.2%, and an energy efficiency of 84% at a constant power of 10 kW. This high Coulombic efficiency demonstrates that leakage current is well controlled when multiple cells are connected in series.

[0067] By adding a liquid guide plate, a common pipeline is formed within the stack, reducing the machining requirements for the end plates. This also simplifies and streamlines the layout of the external piping, facilitating maintenance. This achieved a 10% cost savings, achieving the desired effect.

Claims

1. A liquid flow battery stack, characterized in that: The stack includes a left end plate, a left liquid guide plate, a right liquid guide plate, a right end plate stacked in sequence, and single cells located between the left liquid guide plate and the right liquid guide plate and separated from left to right by bipolar plates. The single cell comprises a positive electrode located in a through hole in the middle of a positive electrode frame, an ion conducting membrane, and a negative electrode located in a through hole in the middle of a negative electrode frame, which are stacked in sequence from left to right. The number of cells separated by bipolar plates is M, where M is an integer greater than or equal to 4; N through-holes serving as positive electrode electrolyte inlets, N through-holes serving as positive electrode electrolyte outlets, N through-holes serving as negative electrode electrolyte inlets, and N through-holes serving as negative electrode electrolyte outlets are respectively provided at corresponding positions on the bipolar plate; the number of positive electrode electrolyte inlets, positive electrode electrolyte outlets, negative electrode electrolyte inlets, and negative electrode electrolyte outlets on the bipolar plate are all the same; if M is an even number, N is 2 to M / 2; if M is an odd number, N is 2 to (M+1) / 2; N is an odd number, and at the corresponding positions of the through holes on the bipolar plates, N-1 blind holes as the positive electrode electrolyte inlet, N-1 blind holes as the positive electrode electrolyte outlet, N-1 blind holes as the negative electrode electrolyte inlet, and N-1 blind holes as the negative electrode electrolyte outlet are opened on the right liquid guide plate; 1 through hole as the positive electrode electrolyte inlet and N-1 blind holes as the positive electrode electrolyte inlet, 1 through hole as the positive electrode electrolyte outlet and N-1 blind holes as the positive electrode electrolyte outlet, 1 through hole as the negative electrode electrolyte inlet and N-1 blind holes as the negative electrode electrolyte inlet, 1 through hole as the negative electrode electrolyte outlet and N-1 blind holes as the negative electrode electrolyte outlet are opened on the left liquid guide plate; Alternatively, N is an even number, and at the corresponding positions of the through holes on the bipolar plate, N blind holes as the positive electrode electrolyte inlet, N blind holes as the positive electrode electrolyte outlet, N blind holes as the negative electrode electrolyte inlet, and N blind holes as the negative electrode electrolyte outlet are opened on the right liquid guide plate; the left liquid guide plate is provided with 1 through hole as the positive electrode electrolyte inlet and N-2 blind holes as the positive electrode electrolyte inlet, 1 through hole as the positive electrode electrolyte outlet and N-2 blind holes as the positive electrode electrolyte outlet, 1 through hole as the negative electrode electrolyte inlet and N-2 blind holes as the negative electrode electrolyte inlet, 1 through hole as the negative electrode electrolyte outlet, and N-2 blind holes as the negative electrode electrolyte outlet; At the corresponding position of the through hole on the left liquid guide plate, a through hole as the positive electrode electrolyte inlet, a through hole as the positive electrode electrolyte outlet, a through hole as the cathode electrolyte inlet, and a through hole as the negative electrode electrolyte outlet are opened on the left end plate; From left to right, the left liquid guide plate and the positive electrode electrolyte inlet at the corresponding position on the bipolar plate are connected in series in sequence to form a total of N positive electrode electrolyte inlet channels; from left to right, the end plate and the positive electrode electrolyte outlet at the corresponding position on the bipolar plate are connected in series in sequence to form a total of N positive electrode electrolyte outlet channels; from left to right, the end plate and the negative electrode electrolyte inlet at the corresponding position on the bipolar plate are connected in series in sequence to form a total of N negative electrode electrolyte inlet channels; from left to right, the end plate and the negative electrode electrolyte outlet at the corresponding position on the bipolar plate are connected in series in sequence to form a total of N negative electrode electrolyte outlet channels; The left side of the channel is the head and the right side is the tail; The N positive electrode electrolyte inlet channels on the left liquid guide plate and the bipolar plate are connected in pairs in sequence through the channels between the blind holes inside the left liquid guide plate and the right liquid guide plate body, and in pairs in sequence to form a common channel with one end closed and the other end open. The open end of the common channel is connected to the positive electrode electrolyte inlet channel of the left end plate; The N positive electrode electrolyte outlet channels on the left liquid guide plate and the bipolar plate are connected in pairs and in pairs respectively through the channels between the blind holes inside the left liquid guide plate and the right liquid guide plate to form a common channel with one end closed and the other end open. The open end of the common channel is connected to the positive electrode electrolyte outlet channel of the left end plate. The N negative electrode electrolyte inlet channels on the left liquid guide plate and the bipolar plate are connected in pairs in sequence through the channels between the blind holes inside the left liquid guide plate and the right liquid guide plate body, and in pairs in sequence, to form a common channel with one end closed and the other end open, and the open end of the common channel is connected to the negative electrode electrolyte inlet channel of the left end plate; The N negative electrode electrolyte outlet channels on the left liquid guide plate and the bipolar plate are connected in pairs in sequence through the channels between the blind holes inside the left liquid guide plate and the right liquid guide plate bodies, and in pairs in sequence, to form a common channel with one end closed and the other end open, and the open end of the common channel is connected to the negative electrode electrolyte outlet channel of the left end plate; From left to right, one end of the positive electrode in the 1st to Mth single cells is connected to one channel of the N positive electrolyte inlet channels, and the other end is connected to one channel of the N positive electrolyte outlet channels; and the positive electrodes of adjacent single cells are respectively connected to different channels of the N positive electrolyte inlet channels, and the positive electrodes of adjacent single cells are respectively connected to different channels of the N positive electrolyte outlet channels; and the other end of the single cell connected to a positive electrolyte inlet channel is connected to a positive electrolyte outlet channel; From left to right, one end of the negative electrode in the 1st to Mth single cells is connected to one channel of the N negative electrode electrolyte inlet channels, and the other end is connected to one channel of the N negative electrode electrolyte outlet channels; and the negative electrodes of adjacent single cells are respectively connected to different channels of the N negative electrode electrolyte inlet channels, and the negative electrodes of adjacent single cells are respectively connected to different channels of the N negative electrode electrolyte outlet channels; and the other end of the single cell connected to a negative electrode electrolyte inlet channel is connected to a negative electrode electrolyte outlet channel.

2. A flow battery stack structure, characterized in that: The battery stack includes a left end plate, a left liquid guide plate, a right liquid guide plate, a right end plate, and single cells located between the left liquid guide plate and the right liquid guide plate, which are separated from left to right by bipolar plates. The single cell comprises a positive electrode located in a through hole in the middle of a positive electrode frame, an ion conducting membrane, and a negative electrode located in a through hole in the middle of a negative electrode frame, which are stacked in sequence from left to right. The number of cells separated by bipolar plates is M*N; N through-holes serving as positive electrode electrolyte inlets, N through-holes serving as positive electrode electrolyte outlets, N through-holes serving as negative electrode electrolyte inlets, and N through-holes serving as negative electrode electrolyte outlets are respectively provided at corresponding positions on the bipolar plate; the number of positive electrode electrolyte inlets, positive electrode electrolyte outlets, negative electrode electrolyte inlets, and negative electrode electrolyte outlets on the bipolar plate are all the same; N is an odd number, and at the corresponding positions of the through holes on the bipolar plates, N-1 blind holes as the positive electrode electrolyte inlet, N-1 blind holes as the positive electrode electrolyte outlet, N-1 blind holes as the negative electrode electrolyte inlet, and N-1 blind holes as the negative electrode electrolyte outlet are opened on the right liquid guide plate; 1 through hole as the positive electrode electrolyte inlet and N-1 blind holes as the positive electrode electrolyte inlet, 1 through hole as the positive electrode electrolyte outlet and N-1 blind holes as the positive electrode electrolyte outlet, 1 through hole as the negative electrode electrolyte inlet and N-1 blind holes as the negative electrode electrolyte inlet, 1 through hole as the negative electrode electrolyte outlet, and N-1 blind holes as the negative electrode electrolyte outlet are opened on the left liquid guide plate; Alternatively, N is an even number, and at the corresponding positions of the through holes on the bipolar plate, N blind holes as the positive electrode electrolyte inlet, N blind holes as the positive electrode electrolyte outlet, N blind holes as the negative electrode electrolyte inlet, and N blind holes as the negative electrode electrolyte outlet are opened on the right liquid guide plate; 1 through hole as the positive electrode electrolyte inlet and N-2 blind holes as the positive electrode electrolyte inlet, 1 through hole as the positive electrode electrolyte outlet and N-2 blind holes as the positive electrode electrolyte outlet, 1 through hole as the negative electrode electrolyte inlet and N-2 blind holes as the negative electrode electrolyte inlet, 1 through hole as the negative electrode electrolyte outlet, and N-2 blind holes as the negative electrode electrolyte outlet are opened on the left liquid guide plate; At the corresponding position of the through hole on the left liquid guide plate, a through hole as the positive electrode electrolyte inlet, a through hole as the positive electrode electrolyte outlet, a through hole as the cathode electrolyte inlet, and a through hole as the negative electrode electrolyte outlet are opened on the left end plate; From left to right, the left liquid guide plate and the positive electrode electrolyte inlet at the corresponding position on the bipolar plate are connected in series in sequence to form a total of N positive electrode electrolyte inlet channels; from left to right, the end plate and the positive electrode electrolyte outlet at the corresponding position on the bipolar plate are connected in series in sequence to form a total of N positive electrode electrolyte outlet channels; from left to right, the end plate and the negative electrode electrolyte inlet at the corresponding position on the bipolar plate are connected in series in sequence to form a total of N negative electrode electrolyte inlet channels; from left to right, the end plate and the negative electrode electrolyte outlet at the corresponding position on the bipolar plate are connected in series in sequence to form a total of N negative electrode electrolyte outlet channels; The left side of the channel is the head and the right side is the tail; The N positive electrode electrolyte inlet channels on the left liquid guide plate and the bipolar plate are connected in pairs in sequence through the channels between the blind holes inside the left liquid guide plate and the right liquid guide plate body, and in pairs in sequence to form a common channel with one end closed and the other end open. The open end of the common channel is connected to the positive electrode electrolyte inlet channel of the left end plate; The N positive electrode electrolyte outlet channels on the left liquid guide plate and the bipolar plate are connected in pairs and in pairs respectively through the channels between the blind holes inside the left liquid guide plate and the right liquid guide plate to form a common channel with one end closed and the other end open. The open end of the common channel is connected to the positive electrode electrolyte outlet channel of the left end plate. The N negative electrode electrolyte inlet channels on the left liquid guide plate and the bipolar plate are connected in pairs in sequence through the channels between the blind holes inside the left liquid guide plate and the right liquid guide plate body, and in pairs in sequence, to form a common channel with one end closed and the other end open, and the open end of the common channel is connected to the negative electrode electrolyte inlet channel of the left end plate; The N negative electrode electrolyte outlet channels on the left liquid guide plate and the bipolar plate are connected in pairs in sequence through the channels between the blind holes inside the left liquid guide plate and the right liquid guide plate bodies, and in pairs in sequence, to form a common channel with one end closed and the other end open, and the open end of the common channel is connected to the negative electrode electrolyte outlet channel of the left end plate; From left to right, one end of the positive electrode in the Kth cell and the N+Kth cell is connected to the Kth channel of the N positive electrode electrolyte inlet channels, and the other end is connected to the Kth channel of the N positive electrode electrolyte outlet channels; from left to right, one end of the negative electrode in the Kth cell and the N+Kth cell is connected to the Kth channel of the N negative electrode electrolyte inlet channels, and the other end is connected to the Kth channel of the N negative electrode electrolyte outlet channels; K represents an integer from 1 to N, M is an integer greater than or equal to 5; N is an integer greater than or equal to 3.

3. The flow battery stack structure according to claim 2, characterized in that: N positive electrode electrolyte inlet channels and N positive electrode electrolyte outlet channels are respectively connected to the positive electrode electrolyte storage tank outside the fuel cell stack; N negative electrode electrolyte inlet channels and N negative electrode electrolyte outlet channels are respectively connected to the negative electrode electrolyte storage tank outside the fuel cell stack.

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