Shunting runner structure of large-size flow battery

Abstract

The utility model discloses a flow channel structure of a large-size flow battery, in particular to a shunting flow channel structure of the large-size flow battery, the shunting flow channel structure is a structural design of a main flow channel and N stages of branch flow channels, N is greater than or equal to 2, the first stage to the (N-1) th stage are straight branch flow channels, and the Nth stage is a snake-shaped or interdigital branch flow channel; wherein every two adjacent stages of straight branch flow channels are connected, the bipolar plate is divided into a plurality of areas with the same area by the multiple stages of straight branch flow channels stage by stage, and a plurality of Nth-stage snake-shaped or interdigital branch flow channels connected with the (N-1) th-stage straight branch flow channels are uniformly distributed in each local area; and the first-stage straight branch runner is connected with the main runner. According to the utility model, the technical problem that the distribution uniformity of the electrolyte in the large-size flow battery is improved by distributing the electrolyte in a shunting manner is solved. The mass transfer loss of the large-size flow battery adopting the shunting flow channel structure is greatly reduced, and the battery voltage efficiency and the system efficiency are remarkably improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to a flow channel structure of large size flow battery, especially a shunt flow channel structure of large size flow battery. BACKGROUND

[0002] The traditional flow channel structure (such as the traditional snake type flow channel structure as shown in the figure and the traditional interdigital type flow channel structure as shown in the figure) of the large size flow battery porous electrode has the problems of small electrolyte flow rate and uneven distribution, slow reactant transfer speed and uneven distribution, and large pressure drop of the battery inlet and outlet, which ultimately leads to low energy efficiency of the flow battery. Figure 1 Figure 3 The above problems are closely related to the flow channel structure. On the one hand, in the large size flow battery, the flow channel cross-sectional area increases while the electrode thickness remains unchanged, which leads to relatively small flow resistance of the electrolyte in the flow channel, so the electrolyte is more inclined to flow in the flow channel rather than penetrating into the porous electrode, ultimately resulting in small electrolyte flow rate in the porous electrode. In addition, the electrolyte penetration is mainly concentrated at both ends of the flow channel due to the influence of pressure difference distribution, and the electrolyte penetration amount in the middle part of the flow channel is less, so the electrolyte flow rate distribution in the porous electrode is also less uniform. Finally, due to the substantial increase in the size of the flow battery, such as an increase of 100 times from 3cm X 3cm to 30cm X 30cm, in order to ensure the electrolyte supply per unit area, the electrolyte flow rate at the battery inlet should also be increased by 100 times, and the substantial increase in flow rate ultimately leads to a substantial increase in pressure drop. The above adverse effects will reduce the energy efficiency of the flow battery.

[0003] Therefore, the applicant proposes the utility model. SUMMARY

[0004] In view of the defects of the prior art, the purpose of the utility model is to provide a shunt flow channel structure of large size flow battery, that is, on the surface of the bipolar plate outside the active area, the electrolyte is distributed in a shunt manner, so that the electrolyte is uniformly distributed in each branch flow channel, which can not only ensure the uniformity of electrolyte distribution and increase the mass transfer effect, but also significantly reduce the pressure drop and pump consumption of the flow battery system.

[0005] In order to achieve the above purpose, the utility model designs a shunt flow channel structure of large size flow battery, which is a structure design of main flow channel and N level branch flow channel, N≥2, the first level to the N-1 level are straight branch flow channels, and the N level is a snake type or interdigital type branch flow channel;

[0006] Wherein, each two adjacent levels of straight branch flow channels are connected, and the multiple levels of straight branch flow channels gradually divide the bipolar plate into multiple areas with the same area, and a plurality of N level snake type or interdigital type branch flow channels connected with the N-1 level straight branch flow channels are uniformly arranged in each local area.​

[0007] Wherein, the first level straight branch channel is connected with the main channel, and the main channel is provided with electrolyte inlet and outlet.

[0008] The above-mentioned large-size flow battery shunt flow channel structure, the inlet and outlet on the main channel are preferably located on the symmetric side of the bipolar plate, which is more conducive to the uniform arrangement of the multi-stage straight channel on the bipolar plate.

[0009] The design idea of the utility model is:

[0010] The utility model discloses a step-by-step shunt mode to distribute electrolyte from the main channel inlet to each level branch channel, and then collect electrolyte from each level branch channel to the main channel outlet. The shunt flow channel structure can evenly distribute electrolyte to each branch channel, thereby realizing the uniform distribution of electrolyte in the porous electrode of the large-size flow battery.

[0011] Compared with the prior art, the shunt flow channel structure of the large-size flow battery has the following technical effects:

[0012] The large-size flow battery using the shunt flow channel structure can evenly distribute electrolyte in each branch channel, which on the one hand ensures the uniformity of active material supply and improves the mass transfer effect, and on the other hand reduces the system pressure drop and pump power loss, which can ensure the sealing of the system and is also conducive to further improving the flow of electrolyte. In general, the large-size flow battery using the shunt flow channel structure has a significantly reduced mass transfer loss, and the battery voltage efficiency and system efficiency are significantly improved.

[0013] The shunt flow channel structure is suitable for different sizes of flow batteries, and the larger the battery size, the more the number of branch channel classification, that is, the larger N (N≥2), the more obvious the effect. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a schematic diagram of a traditional snake-type flow channel structure;

[0015] Figure 2 is a schematic diagram of a new shunt snake-type flow channel structure;

[0016] Figure 3 is a schematic diagram of a traditional snake-type flow channel structure;

[0017] Figure 4 is a schematic diagram of a new shunt interdigital flow channel structure.

[0018] In the figure: main channel 1, straight branch channel 2, snake-type branch channel 3, bipolar plate 4, interdigital branch channel 5. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art belong to the scope of protection of the present application.

[0020] As shown in the drawings, as an embodiment of the present application, a flow channel structure of a large-size flow battery provided in the embodiment is a structure design of a main flow channel 1 and two-stage branch flow channels, a first stage is a straight branch flow channel 2, and a second stage is a snake-type branch flow channel 3. Figure 2 Among them, the first-stage straight branch flow channel 2 divides the bipolar plate 4 into three areas of the same size, and three second-stage snake-type branch flow channels 3 connected with the first-stage straight branch flow channel 2 are arranged in each local area.

[0021] Among them, the first-stage straight branch flow channel 2 is connected with the main flow channel 1, the main flow channel 1 is provided with electrolyte inlets and outlets, and the inlets and outlets are respectively located on the symmetric side edges of the bipolar plate 4.

[0022] The application of the above flow channel structure in a large-size all-vanadium flow battery is verified by experiments in the following embodiment.

[0023] The electrolyte flow rate in a porous electrode, the pressure drop at the inlet and outlet of the battery, and the energy efficiency of the battery of a small-size (electrode area of 3cm X 3cm) all-vanadium flow battery and a large-size (electrode area of 30cm X 30cm) all-vanadium flow battery using different snake-type flow channel structures (traditional snake-type flow channel structure and new split snake-type flow channel structure) are shown in Table 1. As shown in the table, when the size of the all-vanadium flow battery is increased, the energy efficiency of the large-size all-vanadium flow battery using the split snake-type flow channel structure is closest to that of the small-size all-vanadium flow battery using the traditional snake-type flow channel structure, and is much higher than that of the large-size all-vanadium flow battery using the traditional snake-type flow channel structure (5%).

[0024]

[0025] As a second embodiment of the present application, the flow channel structure of a large-size flow battery provided in the embodiment is basically consistent with the first embodiment in the foregoing. As shown in the drawings, but the second-stage branch flow channel in the embodiment is an interdigital branch flow channel 5.

[0026] Figure 4 Similarly, the application of the above flow channel structure in a large-size all-vanadium flow battery is verified by experiments in the following embodiment.

[0027] ​​

[0028] The energy efficiencies of small-size (electrode area of 3cm X 3cm) and large-size (electrode area of 30cm X 30cm) all-vanadium redox flow batteries using different flow channel structures are shown in Table 2, and the energy efficiencies under different flow rates and current densities are calculated. As shown in the table, when the size of the battery is increased, the energy efficiency of the all-vanadium redox flow battery using the split-fork flow channel structure is closest to that of the small-size flow battery using the traditional fork flow channel structure, and is much higher than that of the large-size all-vanadium redox flow battery using the traditional fork flow channel structure (up to 10%).

[0029]

[0030] The flow channel processing mode on the bipolar plate 4 in all the above examples is laser cutting.

[0031] The split-snake or fork flow channel structure proposed in all the above examples can be applied to large-size all-vanadium redox flow batteries to promote the mass transfer effect of large-size flow batteries, and ultimately achieve the goal of improving the energy efficiency of the flow battery. In addition, based on the split idea, more levels of straight branch flow channels 2 and the last level of snake or fork branch flow channels can be generated according to the specific size of the flow channel and the specific mass transfer requirement.

[0032] The utility model is not limited to the above best implementation, anyone can draw other various forms of product under the enlightenment of the utility model, but no matter make any change in its shape or structure, if it has the same or similar technical scheme with the application, falls in the protection scope of the utility model.

Claims

1. A shunt channel structure for a large-size flow battery, characterized in that: The diversion channel structure is a design of a main channel and N-level branch channels, where N≥2. The first to N-1 levels are all straight branch channels, and the Nth level is a serpentine or interdigitated branch channel. In this system, each pair of adjacent straight tributaries is connected, and the multi-level straight tributaries divide the bipolar plate into multiple regions of equal area. In each local region, multiple Nth-level serpentine or interdigitated tributaries connected to the N-1th-level straight tributary are evenly distributed. The first-stage straight tributary is connected to the main channel, and the main channel is provided with an electrolyte inlet and outlet.

2. The shunt channel structure for a large-size flow battery according to claim 1, characterized in that: The inlet and outlet of the main channel are located on the symmetrical sides of the bipolar plate.

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