Flow channel current-conducting plate for flow battery

Abstract

The utility model provides a flow channel current-conducting plate for a flow battery, which is characterized by comprising a graphite plate, a liquid inlet flow channel and a liquid outlet flow channel are transversely arranged on the graphite plate, a liquid inlet branch flow channel is longitudinally communicated with the liquid inlet flow channel, a liquid outlet branch flow channel is longitudinally communicated with the liquid outlet flow channel, and the liquid inlet branch flow channel is communicated with the liquid outlet branch flow channel. The liquid inlet branch flow channels and the liquid outlet branch flow channels are arranged at intervals; a liquid inlet and a liquid outlet are respectively formed in one end of the liquid inlet runner and one end of the liquid outlet runner; the liquid inlet flow channel, the liquid outlet flow channel, the liquid inlet branch flow channel and the liquid outlet branch flow channel are all open flow channels, and the section of each flow channel is in a large semicircular shape. According to the structure, the defects in the prior art are overcome, the contact internal resistance of the current-conducting plate and an electrode material can be reduced by scientifically and reasonably improving the current-conducting plate structure in the prior art, meanwhile, the problem of concentration polarization caused by the fact that the concentration of active substances in electrolyte is reduced in the direction of the liquid outlet is solved, and the electrochemical performance of the battery is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of flow battery structures, and in particular relates to a flow channel conductive plate for a flow battery. Background Art

[0002] As a large-scale energy storage device, the flow battery has received more and more extensive attention due to its advantages such as long life, fast response, non-combustible, non-explosive, low pollution, high efficiency, and the output power and storage capacity of the system can be designed separately. The flow battery consists of end plates, bipolar plates, electrode materials, ion exchange membranes and electrolytes. As a key material of the flow battery, the bipolar plate not only plays the role of connecting the batteries in series, but also its flow channels control the flow mode of the electrolyte. The flow channel structure directly affects the distribution uniformity of the electrolyte and the proton conductivity. A good flow mode can reduce the concentration polarization in the battery and improve the overall efficiency of the battery.

[0003] Currently, on the conductive plate for the general flow battery, electrolyte flow channels with equal depths are engraved. The flow velocity of the electrolyte along the direction of the inlet and outlet is basically the same. However, as the reaction progresses, the concentration of the reactants gradually decreases along the direction of the inlet and outlet, usually resulting in a gradual increase in the concentration polarization along the direction of the inlet and outlet. Especially at the end of charge and discharge or under high current density, the influence is significant, leading to a decline in the overall performance of the battery. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a new type of flow channel conductive plate for a flow battery to solve the problems that the contact area between the existing flow channel battery conductive plate and the electrode material is small, resulting in an increase in contact resistance, and the radius flow of the electrolyte is blocked, leading to an increase in concentration polarization at the end of charge and discharge, and avoiding the reduction of the electrochemical performance of the battery.

[0005] The utility model is realized by the following technical solutions: A flow channel conductive plate for a flow battery, characterized in that: it includes a graphite plate, on which an inlet flow channel and an outlet flow channel are transversely arranged, an inlet branch flow channel is longitudinally communicated on the inlet flow channel, an outlet branch flow channel is longitudinally communicated on the outlet flow channel, and the inlet branch flow channel and the outlet branch flow channel are arranged at intervals; an inlet and an outlet are respectively arranged at one end of the inlet flow channel and the outlet flow channel;

[0006] The inlet flow channel, the outlet flow channel, the inlet branch flow channel and the outlet branch flow channel are all open channels, and the cross-section is a large semi-circular shape.

[0007] Further: An auxiliary flow channel is arranged between two adjacent inlet branch flow channels and two adjacent outlet branch flow channels, and the inner diameter of the auxiliary flow channel becomes larger along the flow direction of the electrolyte.

[0008] Further: The auxiliary flow channel is frustum-shaped, and the diameter ratio of both ends of the frustum is 1:1.1.

[0009] Further: the graphite plate is a high-density flexible graphite plate.

[0010] Further: conductive carbon black is coated on the surface of the graphite plate.

[0011] Further: in the large semi-circular cross-section, the length of the secant chord is the same as the radius.

[0012] The beneficial effects of the present utility model are as follows: this structure overcomes the defects in the prior art. Through scientific and reasonable improvement of the conductive plate structure in the prior art, the contact internal resistance between the conductive plate and the electrode material can be reduced, and at the same time, the concentration polarization problem caused by the decrease in the concentration of active substances in the electrolyte along the direction of the liquid outlet can be improved, thereby improving the electrochemical performance of the battery. Description of the Drawings

[0013] Figure 1 is the overall structural schematic diagram of the present utility model;

[0014] Figure 2 is Figure 1 the sectional view taken along the A-A direction of

[0015] Figure 3 is Figure 1 the sectional view taken along the B-B direction of

[0016] Figure 4 is Figure 1 the enlarged schematic diagram of the partial structure of

[0017] Explanation of the reference numerals in the figures:

[0018] 100 is the conductive plate body;

[0019] 10 is the liquid inlet flow channel, 11 is the liquid inlet branch flow channel, 12 is the liquid inlet; 20 is the liquid outlet flow channel, 21 is the liquid outlet branch flow channel, 22 is the liquid outlet; 30 is the auxiliary flow channel. Detailed Embodiment

[0020] Referring to the attached Figure 1-4 , the present utility model discloses a flow channel conductive plate for a flow battery, which includes a conductive plate body 100. The conductive plate body is a graphite plate. A liquid inlet flow channel 10 and a liquid outlet flow channel 20 are horizontally arranged on the graphite plate. A liquid inlet branch flow channel 11 is longitudinally communicated on the liquid inlet flow channel 10, and a liquid outlet branch flow channel 21 is longitudinally communicated on the liquid outlet flow channel 20. Moreover, the liquid inlet branch flow channel 11 and the liquid outlet branch flow channel 21 are arranged at intervals and cross each other; a liquid inlet 12 and a liquid outlet 22 are respectively arranged at one end of the liquid inlet flow channel and the liquid outlet flow channel;

[0021] Each flow channel such as the liquid inlet flow channel, the liquid outlet flow channel, the liquid inlet branch flow channel, and the liquid outlet branch flow channel is an open flow channel, and the cross-section is a large semi-circular shape (equivalent to the shape remaining after a small part is cut off from a circle by a straight line, and this straight line is also called a secant chord). Each flow channel is equivalent to a groove and can be formed by grooving on the conductive plate.

[0022] Preferably: An auxiliary flow channel 30 is communicatively provided between two adjacent liquid inlet branch flow channels and two adjacent liquid outlet branch flow channels, and the inner diameter of the auxiliary flow channel increases along the electrolyte flow direction. Each auxiliary flow channel is in the shape of a hollow frustum of a cone, smaller on the side close to the liquid inlet and larger on the side far from the liquid inlet. This structure can greatly improve the problem of concentration polarization caused by the decrease in the concentration of active substances in the electrolyte along the liquid outlet direction, thereby improving the electrochemical performance of the battery.

[0023] Furthermore, the diameter ratio of the two ends of the frustum of the cone is 1:1.1.

[0024] Preferably: The graphite plate is a high-density flexible graphite plate.

[0025] Preferably: Conductive carbon black is coated on the non-flow channel part of the graphite plate surface to further improve the conductivity.

[0026] Preferably: In the large semi-circular cross-section, the length of the secant chord is the same as the radius.

[0027] In this solution, a large semi-circular flow channel is adopted. Compared with the traditional engraving method, the contact area between the flow channel conductive plate and the electrode material in this method increases, and the contact internal resistance is small, thereby reducing the ohmic polarization of the battery and improving the electrochemical performance of the battery.

[0028] Taking the conductive plate of this solution as the electrode plate and applying it to a vanadium redox flow battery for testing, at 240 mA / cm 2 The test results are as follows:

[0029] Test item Traditional flow channel conductive plate Conductive plate of the present utility model Battery internal resistance / mΩ 19.6 11.4 Energy efficiency / % 82.9 84.2 Voltage efficiency / % 86.8 88.1

[0030] In summary, the structure of the present utility model reduces the ohmic polarization of the battery through a special flow channel structure, reduces the internal resistance of the battery, and at the same time improves the energy efficiency and voltage efficiency, and overall improves the electrochemical performance of the battery.

Claims

1. A flow channel conductive plate for a flow battery, characterized in that: It includes a graphite plate, on which a liquid inlet flow channel and a liquid outlet flow channel are horizontally arranged. A liquid inlet branch flow channel is longitudinally communicated with the liquid inlet flow channel, and a liquid outlet branch flow channel is longitudinally communicated with the liquid outlet flow channel. The liquid inlet branch flow channel and the liquid outlet branch flow channel are arranged at intervals. A liquid inlet and a liquid outlet are respectively arranged at one end of the liquid inlet flow channel and the liquid outlet flow channel. The liquid inlet flow channel, the liquid outlet flow channel, the liquid inlet branch flow channel and the liquid outlet branch flow channel are all open channels, and the cross-section is a large semi-circular shape.

2. The flow channel conductive plate for a flow battery according to claim 1, wherein: An auxiliary flow channel is arranged between two adjacent liquid inlet branch flow channels and two adjacent liquid outlet branch flow channels. The inner diameter of the auxiliary flow channel becomes larger along the flowing direction of the electrolyte.

3. The flow channel conductive plate for a flow battery according to claim 2, characterized in that: The auxiliary flow channel is frustum-shaped, and the diameter ratio of the two ends of the frustum is 1:1.

1.

4. The flow channel conductive plate for a flow battery according to claim 1, characterized in that: The graphite plate is a high-density flexible graphite plate.

5. A flow channel conductive plate for a flow battery according to claim 1, characterized in that: Conductive carbon black is coated on the surface of the graphite plate.

6. The flow channel conductive plate for a flow battery according to claim 1, wherein: In the large semi-circular cross-section, the length of the chord cut is the same as the radius.

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