A zinc-bromine single fluid battery

Abstract

The application discloses a zinc-bromine single liquid flow battery and belongs to the technical field of liquid flow battery energy storage, wherein the zinc-bromine single liquid flow battery is a single battery or a battery pack formed by connecting two or more single batteries in series, and the single battery mainly comprises a negative electrode frame, a negative carbon felt electrode arranged in a through hole in the middle of the negative electrode frame, a diaphragm, a positive carbon felt electrode arranged in a through hole in the middle of a positive electrode frame and the positive electrode frame which are sequentially stacked. The application reduces the flow radius of the electrolyte inlet flow channel, the inlet distribution flow channel, the outlet flow channel and the outlet distribution flow channel of the positive electrode frame, increases the flow resistance of the positive electrode frame, and solves the problems of low coulomb efficiency and short cycle life of the zinc-bromine single liquid flow battery caused by the expansion of the positive bromine during the operation of the zinc-bromine single liquid flow battery.

Description

Technical Field

[0001] This invention belongs to the field of flow battery energy storage technology, specifically relating to a zinc-bromine single flow battery. Background Technology

[0002] Zinc-bromine single-flow batteries are a novel, low-cost, highly stable, and long-life flow battery energy storage technology with high energy density. A key feature is that the positive electrode active material is sealed inside the battery, eliminating environmental problems such as bromine pollution. However, because the bromine at the positive electrode is stationary, during battery charging, bromide ions lose electrons to form elemental bromine, which expands in volume. This causes the elemental bromine, originally located inside the electrode frame, to be squeezed into the battery's common flow channels, resulting in the loss of active material, decreased battery performance, and reduced battery uniformity. Therefore, suppressing the loss of elemental bromine inside the electrode frame is crucial for improving the performance of zinc-bromine single-flow batteries. Summary of the Invention

[0003] To address the aforementioned technical problems, the present invention aims to provide a zinc-bromine single-liquid flow battery.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A zinc-bromine single-flow battery is a single cell or a battery pack consisting of two or more single cells connected in series. The single cell mainly includes a negative electrode frame, a negative carbon felt electrode placed in a through hole in the middle of the negative electrode frame, a separator, a positive carbon felt electrode placed in a through hole in the middle of the positive electrode frame, and a positive electrode frame, which are stacked in sequence.

[0006] Furthermore, the negative electrode frame is a rectangular plate with a through hole in the middle. On one side surface A of the plate, opposite to the through hole (i.e., the upper and lower sides of surface A), there are negative electrolyte inlet channels and negative electrolyte outlet channels, as well as electrolyte inlet distribution channels connecting the negative electrolyte inlet channels and the through hole in the middle, and electrolyte outlet distribution channels connecting the negative electrolyte outlet channels and the through hole in the middle.

[0007] Furthermore, the positive electrode frame is a rectangular plate with a through hole in the middle. On one side surface B of the plate, on the two opposite sides of the through hole (i.e., the upper and lower sides of surface B), there are positive electrolyte inlet channels and positive electrolyte outlet channels, as well as electrolyte inlet distribution channels connecting the positive electrolyte inlet channels and the through hole in the middle, and electrolyte outlet distribution channels connecting the positive electrolyte outlet channels and the through hole in the middle.

[0008] Furthermore, the electrolyte inlet channels of each negative electrode frame are connected to each other through a common negative electrolyte inlet channel, and the electrolyte outlet channels of each negative electrode frame are connected to each other through a common negative electrolyte outlet channel.

[0009] Furthermore, the electrolyte inlet channels of each positive electrode frame are connected to each other through a common positive electrolyte inlet channel, and the electrolyte outlet channels of each positive electrode frame are connected to each other through a common positive electrolyte outlet channel.

[0010] Furthermore, the flow radii of the positive electrolyte inlet channel and the positive electrolyte outlet channel are both smaller than those of the negative electrolyte inlet channel and the negative electrolyte outlet channel.

[0011] Furthermore, the flow radius of the negative electrode electrolyte inlet channel and the negative electrode electrolyte outlet channel is 2-6 times that of the positive electrode electrolyte inlet channel and the positive electrode electrolyte outlet channel.

[0012] Furthermore, the flow radius of the positive electrolyte inlet channel and the positive electrolyte outlet channel is between 1mm and 3mm.

[0013] Furthermore, the flow radius of the negative electrode electrolyte inlet channel and the negative electrode electrolyte outlet channel is between 4mm and 6mm.

[0014] Furthermore, the flow radii of the positive electrolyte inlet distribution channel and the positive electrolyte outlet distribution channel are both smaller than the flow radii of the negative electrolyte inlet distribution channel and the negative electrolyte outlet distribution channel.

[0015] Furthermore, the flow radius of the negative electrode electrolyte inlet distribution channel and the negative electrode electrolyte outlet distribution channel is 2-6 times that of the positive electrode electrolyte inlet distribution channel and the positive electrode electrolyte outlet distribution channel.

[0016] Furthermore, the flow radius of the positive electrolyte inlet distribution channel and the positive electrolyte outlet distribution channel is between 0.5mm and 1.5mm.

[0017] Furthermore, the flow radius of the negative electrode electrolyte inlet distribution channel and the negative electrode electrolyte outlet distribution channel is between 2mm and 3mm.

[0018] Another aspect of the present invention provides a method for improving the coulombic efficiency and extending the cycle life of a zinc-bromine single-flow battery, using the aforementioned zinc-bromine single-flow battery.

[0019] The advantages of this invention over the prior art are as follows:

[0020] This invention reduces the flow radius of the electrolyte inlet channel, inlet distribution channel, outlet channel, and outlet distribution channel of the positive electrode frame, and increases the flow resistance of the positive electrode frame, thus solving the problem of low coulombic efficiency and short cycle life of zinc-bromine single-flow batteries due to the expansion of bromine in the positive electrode during operation. Attached Figure Description

[0021] To more clearly illustrate the embodiments of the present invention, the accompanying drawings involved in the embodiments will be briefly described below.

[0022] Figure 1 The electrode frame structure of the present invention includes: 1: negative electrolyte outlet channel, 2: negative electrolyte outlet distribution channel, 3: positive electrolyte outlet channel, 4: positive electrolyte inlet channel, 5: negative electrolyte inlet distribution channel, and 6: negative electrolyte inlet channel.

[0023] Figure 2 The electrode frame structure is shown in the example, where 1: negative electrode electrolyte outlet channel, 2: negative electrode electrolyte outlet distribution channel, 3: positive electrode electrolyte outlet channel, 4: positive electrode electrolyte inlet channel, 5: negative electrode electrolyte inlet distribution channel, and 6: negative electrode electrolyte inlet channel. Detailed Implementation

[0024] The present invention will be described in detail below with reference to the embodiments. However, the implementation of the present invention is not limited thereto. Obviously, the embodiments described below are only some embodiments of the present invention. For those skilled in the art, other similar embodiments can be obtained without creative effort and all fall within the protection scope of the present invention.

[0025] Comparative Example 1

[0026] Comparative Example 1 uses a traditional electrode frame structure to assemble a zinc-bromine single-flow battery pack. Ten single cells are arranged between two current collectors. Each single cell includes a negative electrode frame, a negative carbon felt electrode placed in a through hole in the middle of the negative electrode frame, a separator, a positive carbon felt electrode placed in a through hole in the middle of the positive electrode frame, and a positive electrode frame. The electrolyte inlet channels of each negative electrode frame are connected through a common negative electrolyte inlet channel, and the electrolyte outlet channels of each negative electrode frame are connected through a common negative electrolyte outlet channel. Similarly, the electrolyte inlet channels of each positive electrode frame are connected through a common positive electrolyte inlet channel, and the electrolyte outlet channels of each positive electrode frame are connected through a common positive electrolyte outlet channel. The flow radius of the negative electrolyte inlet channel, negative electrolyte outlet channel, positive electrolyte inlet channel, and positive electrolyte outlet channel is 6 mm; the flow radius of the negative electrolyte inlet distribution channel, negative electrolyte outlet distribution channel, positive electrolyte inlet distribution channel, and positive electrolyte outlet distribution channel is 3 mm. A separator is placed between the positive and negative electrode frames, and bipolar plates are set on both sides of the single cell. The electrolyte uses 2 mol / L zinc bromide solution, 3 mol / L potassium chloride solution, and 0.8 mol / L MEP complexing agent. The specific electrode dimensions, number of stack cells, and charge / discharge regime are shown below:

[0027] Electrode area: 800 cm²2 ;

[0028] Number of fuel cell stack sections: 10;

[0029] Current density: 40 mA / cm 2 Charging time: 1 hour; Discharge cut-off voltage: 8V.

[0030] The battery has a coulombic efficiency of 87.2%, a voltage efficiency of 78.4%, and an energy efficiency of 68.4%.

[0031] Comparative Example 2

[0032] Comparative Example 2 uses a traditional electrode frame structure to assemble a zinc-bromine single-flow battery pack. Ten single cells are arranged between two current collectors. Each single cell includes a negative electrode frame, a negative carbon felt electrode placed in a through hole in the middle of the negative electrode frame, a separator, a positive carbon felt electrode placed in a through hole in the middle of the positive electrode frame, and a positive electrode frame. The electrolyte inlet channels of each negative electrode frame are connected through a common negative electrolyte inlet channel, and the electrolyte outlet channels of each negative electrode frame are connected through a common negative electrolyte outlet channel. Similarly, the electrolyte inlet channels of each positive electrode frame are connected through a common positive electrolyte inlet channel, and the electrolyte outlet channels of each positive electrode frame are connected through a common positive electrolyte outlet channel. The flow radius of the negative electrolyte inlet channel, negative electrolyte outlet channel, positive electrolyte inlet channel, and positive electrolyte outlet channel is 6 mm; the flow radius of the negative electrolyte inlet distribution channel and negative electrolyte outlet distribution channel is 1 mm; and the flow radius of the positive electrolyte inlet distribution channel and positive electrolyte outlet distribution channel is 3 mm. A separator is placed between the positive and negative electrode frames, and bipolar plates are set on both sides of the single cell. The electrolyte uses 2 mol / L zinc bromide solution, 3 mol / L potassium chloride solution, and 0.8 mol / L MEP complexing agent. The specific electrode dimensions, number of stack cells, and charge / discharge regime are shown below:

[0033] Electrode area: 800 cm² 2 ;

[0034] Number of fuel cell stack sections: 10;

[0035] Current density: 40 mA / cm 2 Charging time: 1 hour; Discharge cut-off voltage: 8V.

[0036] The battery has a coulombic efficiency of 87.6%, a voltage efficiency of 77.1%, and an energy efficiency of 67.5%.

[0037] Comparative Example 3

[0038] Comparative Example 3 uses a traditional electrode frame structure to assemble a zinc-bromine single-flow battery pack. Ten single cells are arranged between two current collectors. Each single cell includes a negative electrode frame, a negative carbon felt electrode placed in a through hole in the middle of the negative electrode frame, a separator, a positive carbon felt electrode placed in a through hole in the middle of the positive electrode frame, and a positive electrode frame. The electrolyte inlet channels of each negative electrode frame are connected through a common negative electrolyte inlet channel, and the electrolyte outlet channels of each negative electrode frame are connected through a common negative electrolyte outlet channel. Similarly, the electrolyte inlet channels of each positive electrode frame are connected through a common positive electrolyte inlet channel, and the electrolyte outlet channels of each positive electrode frame are connected through a common positive electrolyte outlet channel. The flow radius of the negative electrode electrolyte inlet and outlet channels is 4 mm, and the flow radius of the positive electrode electrolyte inlet and outlet channels is 6 mm; the flow radius of the negative electrode electrolyte inlet distribution channel, negative electrode electrolyte outlet distribution channel, positive electrode electrolyte inlet distribution channel, and positive electrode electrolyte outlet distribution channel is 3 mm. A separator is placed between the positive and negative electrode frames, and bipolar plates are set on both sides of the single cell. The electrolyte uses 2 mol / L zinc bromide solution, 3 mol / L potassium chloride solution, and 0.8 mol / L MEP complexing agent. The specific electrode dimensions, number of stack cells, and charge / discharge regime are shown below:

[0039] Electrode area: 800 cm² 2 ;

[0040] Number of fuel cell stack sections: 10;

[0041] Current density: 40 mA / cm 2 Charging time: 1 hour; Discharge cut-off voltage: 8V.

[0042] The battery has a coulombic efficiency of 84.3%, a voltage efficiency of 75.1%, and an energy efficiency of 63.3%.

[0043] Comparative Example 4

[0044] Comparative Example 4 uses a traditional electrode frame structure to assemble a zinc-bromine single-flow battery pack. Ten single cells are arranged between two current collectors. Each single cell includes a negative electrode frame, a negative carbon felt electrode placed in a through hole in the middle of the negative electrode frame, a separator, a positive carbon felt electrode placed in a through hole in the middle of the positive electrode frame, and a positive electrode frame. The electrolyte inlet channels of each negative electrode frame are connected through a common negative electrolyte inlet channel, and the electrolyte outlet channels of each negative electrode frame are connected through a common negative electrolyte outlet channel. Similarly, the electrolyte inlet channels of each positive electrode frame are connected through a common positive electrolyte inlet channel, and the electrolyte outlet channels of each positive electrode frame are connected through a common positive electrolyte outlet channel. The flow radius of the negative electrode electrolyte inlet and outlet channels is 6 mm, and the flow radius of the positive electrode electrolyte inlet and outlet channels is 4 mm; the flow radius of the negative electrode electrolyte inlet and outlet distribution channels is 1 mm, and the flow radius of the positive electrode electrolyte inlet and outlet distribution channels is 3 mm; a separator is placed between the positive and negative electrode frames, and bipolar plates are set on both sides of the single cell. The electrolyte uses 2 mol / L zinc bromide solution, 3 mol / L potassium chloride solution, and 0.8 mol / L MEP complexing agent. Specific electrode dimensions, number of stack cells, and charge / discharge regime are shown below:

[0045] Electrode area: 800 cm² 2 ;

[0046] Number of fuel cell stack sections: 10;

[0047] Current density: 40 mA / cm 2 Charging time: 1 hour; Discharge cut-off voltage: 8V.

[0048] The battery has a coulombic efficiency of 88.2%, a voltage efficiency of 79.3%, and an energy efficiency of 69.9%.

[0049] Comparative Example 5

[0050] Comparative Example 5 uses a traditional electrode frame structure to assemble a zinc-bromine single-flow battery pack. Ten single cells are arranged between two current collectors. Each single cell includes a negative electrode frame, a negative carbon felt electrode placed in a through hole in the middle of the negative electrode frame, a separator, a positive carbon felt electrode placed in a through hole in the middle of the positive electrode frame, and a positive electrode frame. The electrolyte inlet channels of each negative electrode frame are connected through a common negative electrolyte inlet channel, and the electrolyte outlet channels of each negative electrode frame are connected through a common negative electrolyte outlet channel. The electrolyte inlet channels of each positive electrode frame are connected through a common positive electrolyte inlet channel, and the electrolyte outlet channels of each positive electrode frame are connected through a common positive electrolyte outlet channel. The flow radius of the negative electrode electrolyte inlet and outlet channels is 4 mm, and the flow radius of the positive electrode electrolyte inlet and outlet channels is 6 mm; the flow radius of the negative electrode electrolyte inlet and outlet distribution channels is 3 mm, and the flow radius of the positive electrode electrolyte inlet and outlet distribution channels is 1 mm; a separator is placed between the positive and negative electrode frames, and bipolar plates are set on both sides of the single cell. The electrolyte uses 2 mol / L zinc bromide solution, 3 mol / L potassium chloride solution, and 0.8 mol / L MEP complexing agent. Specific electrode dimensions, number of stack cells, and charge / discharge regime are shown below:

[0051] Electrode area: 800 cm² 2 ;

[0052] Number of fuel cell stack sections: 10;

[0053] Current density: 40 mA / cm 2 Charging time: 1 hour; Discharge cut-off voltage: 8V.

[0054] The battery has a coulombic efficiency of 85.3%, a voltage efficiency of 77.7%, and an energy efficiency of 66.3%.

[0055] Example 1

[0056] Example 1 uses the electrode frame structure provided by this invention to assemble a zinc-bromine single-flow battery pack. Ten single cells are arranged between two current collectors. Each single cell includes a negative electrode frame, a negative carbon felt electrode placed in a through hole in the middle of the negative electrode frame, a separator, a positive carbon felt electrode placed in a through hole in the middle of the positive electrode frame, and a positive electrode frame, which are stacked in sequence. The electrolyte inlet channels of each negative electrode frame are connected through a common negative electrolyte inlet channel, and the electrolyte outlet channels of each negative electrode frame are connected through a common negative electrolyte outlet channel. The electrolyte inlet channels of each positive electrode frame are connected through a common positive electrolyte inlet channel, and the electrolyte outlet channels of each positive electrode frame are connected through a common positive electrolyte outlet channel. The flow radius of the negative electrode electrolyte inlet and outlet channels is 6 mm, and the flow radius of the positive electrode electrolyte inlet and outlet channels is 3 mm. The flow radius of the negative electrode electrolyte inlet and outlet distribution channels is 3 mm, and the flow radius of the positive electrode electrolyte inlet and outlet distribution channels is 1.5 mm. A separator is placed between the positive and negative electrode frames, and bipolar plates are set on both sides of the single cell. The electrolyte uses 2 mol / L zinc bromide solution, 3 mol / L potassium chloride solution, and 0.8 mol / L MEP complexing agent. The specific electrode dimensions, number of stack cells, and charge / discharge regime are shown below:

[0057] Electrode area: 800 cm² 2 ;

[0058] Number of fuel cell stack sections: 10;

[0059] Current density: 40 mA / cm 2 Charging time: 1 hour; Discharge cut-off voltage: 8V.

[0060] The battery has a coulombic efficiency of 92.3%, a voltage efficiency of 81.2%, and an energy efficiency of 74.9%.

[0061] Example 2

[0062] Example 2 uses the electrode frame structure provided by this invention to assemble a zinc-bromine single-flow battery pack. Ten single cells are arranged between two current collectors. Each single cell includes a negative electrode frame, a negative carbon felt electrode placed in a through hole in the middle of the negative electrode frame, a separator, a positive carbon felt electrode placed in a through hole in the middle of the positive electrode frame, and a positive electrode frame, which are stacked in sequence. The electrolyte inlet channels of each negative electrode frame are connected through a common negative electrolyte inlet channel, and the electrolyte outlet channels of each negative electrode frame are connected through a common negative electrolyte outlet channel. The electrolyte inlet channels of each positive electrode frame are connected through a common positive electrolyte inlet channel, and the electrolyte outlet channels of each positive electrode frame are connected through a common positive electrolyte outlet channel. The flow radius of the negative electrode electrolyte inlet and outlet channels is 6 mm, and the flow radius of the positive electrode electrolyte inlet and outlet channels is 2 mm; the flow radius of the negative electrode electrolyte inlet and outlet distribution channels is 3 mm, and the flow radius of the positive electrode electrolyte inlet and outlet distribution channels is 0.5 mm; a separator is placed between the positive and negative electrode frames, and bipolar plates are set on both sides of the single cell. The electrolyte uses 2 mol / L zinc bromide solution, 3 mol / L potassium chloride solution, and 0.8 mol / L MEP complexing agent. Specific electrode dimensions, number of stack cells, and charge / discharge regime are shown below:

[0063] Electrode area: 800 cm² 2 ;

[0064] Number of fuel cell stack sections: 10;

[0065] Current density: 40 mA / cm 2 Charging time: 1 hour; Discharge cut-off voltage: 8V.

[0066] The battery has a coulombic efficiency of 93.3%, a voltage efficiency of 83.2%, and an energy efficiency of 77.6%.

[0067] Example 3

[0068] Example 3 uses the electrode frame structure provided by the present invention to assemble a zinc-bromine single-flow battery pack. Ten single cells are arranged between two current collectors. Each single cell includes a negative electrode frame, a negative carbon felt electrode placed in a through hole in the middle of the negative electrode frame, a separator, a positive carbon felt electrode placed in a through hole in the middle of the positive electrode frame, and a positive electrode frame, which are stacked in sequence. The electrolyte inlet channels of each negative electrode frame are connected through a common negative electrolyte inlet channel, and the electrolyte outlet channels of each negative electrode frame are connected through a common negative electrolyte outlet channel. The electrolyte inlet channels of each positive electrode frame are connected through a common positive electrolyte inlet channel, and the electrolyte outlet channels of each positive electrode frame are connected through a common positive electrolyte outlet channel. The flow radius of the negative electrode electrolyte inlet and outlet channels is 6 mm, and the flow radius of the positive electrode electrolyte inlet and outlet channels is 1 mm. The flow radius of the negative electrode electrolyte inlet and outlet distribution channels is 2 mm, and the flow radius of the positive electrode electrolyte inlet and outlet distribution channels is 1 mm. A separator is placed between the positive and negative electrode frames, and bipolar plates are set on both sides of the single cell. The electrolyte uses 2 mol / L zinc bromide solution, 3 mol / L potassium chloride solution, and 0.8 mol / L MEP complexing agent. The specific electrode dimensions, number of stack cells, and charge / discharge regime are shown below:

[0069] Electrode area: 800 cm² 2 ;

[0070] Number of fuel cell stack sections: 10;

[0071] Current density: 40 mA / cm 2 Charging time: 1 hour; Discharge cut-off voltage: 8V.

[0072] The battery has a coulombic efficiency of 94.1%, a voltage efficiency of 84.5%, and an energy efficiency of 79.5%.

[0073] Example 4

[0074] Example 4 uses the electrode frame structure provided by this invention to assemble a zinc-bromine single-flow battery pack. Ten single cells are arranged between two current collectors. Each single cell includes a negative electrode frame, a negative carbon felt electrode placed in a through hole in the middle of the negative electrode frame, a separator, a positive carbon felt electrode placed in a through hole in the middle of the positive electrode frame, and a positive electrode frame, which are stacked in sequence. The electrolyte inlet channels of each negative electrode frame are connected through a common negative electrolyte inlet channel, and the electrolyte outlet channels of each negative electrode frame are connected through a common negative electrolyte outlet channel. The electrolyte inlet channels of each positive electrode frame are connected through a common positive electrolyte inlet channel, and the electrolyte outlet channels of each positive electrode frame are connected through a common positive electrolyte outlet channel. The flow radius of the negative electrode electrolyte inlet and outlet channels is 4 mm, and the flow radius of the positive electrode electrolyte inlet and outlet channels is 3 mm. The flow radius of the negative electrode electrolyte inlet and outlet distribution channels is 3 mm, and the flow radius of the positive electrode electrolyte inlet and outlet distribution channels is 1 mm. A separator is placed between the positive and negative electrode frames, and bipolar plates are set on both sides of the single cell. The electrolyte uses 2 mol / L zinc bromide solution, 3 mol / L potassium chloride solution, and 0.8 mol / L MEP complexing agent. The specific electrode dimensions, number of stack cells, and charge / discharge regime are shown below:

[0075] Electrode area: 800 cm² 2 ;

[0076] Number of fuel cell stack sections: 10;

[0077] Current density: 40 mA / cm 2 Charging time: 1 hour; Discharge cut-off voltage: 8V.

[0078] The battery has a coulombic efficiency of 92.1%, a voltage efficiency of 82.5%, and an energy efficiency of 75.9%.

[0079] Example 5

[0080] Example 5 uses the electrode frame structure provided by the present invention to assemble a zinc-bromine single-flow battery pack. Ten single cells are arranged between two current collectors. Each single cell includes a negative electrode frame, a negative carbon felt electrode placed in a through hole in the middle of the negative electrode frame, a separator, a positive carbon felt electrode placed in a through hole in the middle of the positive electrode frame, and a positive electrode frame, which are stacked in sequence. The electrolyte inlet channels of each negative electrode frame are connected through a common negative electrolyte inlet channel, and the electrolyte outlet channels of each negative electrode frame are connected through a common negative electrolyte outlet channel. The electrolyte inlet channels of each positive electrode frame are connected through a common positive electrolyte inlet channel, and the electrolyte outlet channels of each positive electrode frame are connected through a common positive electrolyte outlet channel. The flow radius of the negative electrode electrolyte inlet and outlet channels is 4 mm, and the flow radius of the positive electrode electrolyte inlet and outlet channels is 1 mm. The flow radius of the negative electrode electrolyte inlet and outlet distribution channels is 2 mm, and the flow radius of the positive electrode electrolyte inlet and outlet distribution channels is 0.5 mm. A separator is placed between the positive and negative electrode frames, and bipolar plates are set on both sides of the single cell. The electrolyte uses 2 mol / L zinc bromide solution, 3 mol / L potassium chloride solution, and 0.8 mol / L MEP complexing agent. The specific electrode dimensions, number of stack cells, and charge / discharge regime are shown below:

[0081] Electrode area: 800 cm² 2 ;

[0082] Number of fuel cell stack sections: 10;

[0083] Current density: 40 mA / cm 2 Charging time: 1 hour; Discharge cut-off voltage: 8V.

[0084] The battery has a coulombic efficiency of 93.9%, a voltage efficiency of 83.5%, and an energy efficiency of 78.4%.

[0085] Example 6

[0086] Example 6 uses the electrode frame structure provided by the present invention to assemble a zinc-bromine single-flow battery pack. Ten single cells are arranged between two current collectors. Each single cell includes a negative electrode frame, a negative carbon felt electrode placed in a through hole in the middle of the negative electrode frame, a separator, a positive carbon felt electrode placed in a through hole in the middle of the positive electrode frame, and a positive electrode frame, which are stacked in sequence. The electrolyte inlet channels of each negative electrode frame are connected through a common negative electrolyte inlet channel, and the electrolyte outlet channels of each negative electrode frame are connected through a common negative electrolyte outlet channel. The electrolyte inlet channels of each positive electrode frame are connected through a common positive electrolyte inlet channel, and the electrolyte outlet channels of each positive electrode frame are connected through a common positive electrolyte outlet channel. The flow radius of the negative electrode electrolyte inlet and outlet channels is 6 mm, and the flow radius of the positive electrode electrolyte inlet and outlet channels is 3 mm. The flow radius of the negative electrode electrolyte inlet and outlet distribution channels is 2 mm, and the flow radius of the positive electrode electrolyte inlet and outlet distribution channels is 0.5 mm. A separator is placed between the positive and negative electrode frames, and bipolar plates are set on both sides of the single cell. The electrolyte uses 2 mol / L zinc bromide solution, 3 mol / L potassium chloride solution, and 0.8 mol / L MEP complexing agent. The specific electrode dimensions, number of stack cells, and charge / discharge regime are shown below:

[0087] Electrode area: 800 cm² 2 ;

[0088] Number of fuel cell stack sections: 10;

[0089] Current density: 40 mA / cm 2 Charging time: 1 hour; Discharge cut-off voltage: 8V.

[0090] The battery has a coulombic efficiency of 92.8%, a voltage efficiency of 82.9%, and an energy efficiency of 76.9%.

[0091] Example 7

[0092] Example 7 uses the electrode frame structure provided by the present invention to assemble a zinc-bromine single-flow battery pack. Ten single cells are arranged between two current collectors. Each single cell includes a negative electrode frame, a negative carbon felt electrode placed in a through hole in the middle of the negative electrode frame, a separator, a positive carbon felt electrode placed in a through hole in the middle of the positive electrode frame, and a positive electrode frame, which are stacked in sequence. The electrolyte inlet channels of each negative electrode frame are connected through a common negative electrolyte inlet channel, and the electrolyte outlet channels of each negative electrode frame are connected through a common negative electrolyte outlet channel. The electrolyte inlet channels of each positive electrode frame are connected through a common positive electrolyte inlet channel, and the electrolyte outlet channels of each positive electrode frame are connected through a common positive electrolyte outlet channel. The flow radius of the negative electrode electrolyte inlet and outlet channels is 6 mm, and the flow radius of the positive electrode electrolyte inlet and outlet channels is 1 mm; the flow radius of the negative electrode electrolyte inlet and outlet distribution channels is 2 mm, and the flow radius of the positive electrode electrolyte inlet and outlet distribution channels is 3 mm; a separator is placed between the positive and negative electrode frames, and bipolar plates are set on both sides of the single cell. The electrolyte uses 2 mol / L zinc bromide solution, 3 mol / L potassium chloride solution, and 0.8 mol / L MEP complexing agent. Specific electrode dimensions, number of stack cells, and charge / discharge regime are shown below:

[0093] Electrode area: 800 cm² 2 ;

[0094] Number of fuel cell stack sections: 10;

[0095] Current density: 40 mA / cm 2 Charging time: 1 hour; Discharge cut-off voltage: 8V.

[0096] The battery has a coulombic efficiency of 93.8%, a voltage efficiency of 84.1%, and an energy efficiency of 78.8%.

[0097] Table 1. Dimensions of inlet / outlet flow channels and inlet / outlet distribution flow channels for Examples 1-7 and Comparative Examples 1-5

[0098]

[0099] Table 2. Test results of batteries assembled in Examples 1-7 and Comparative Examples 1-5

[0100]

[0101]

[0102] As can be seen from the data in Examples 1-7 and Comparative Examples 1-5, to achieve higher battery coulombic efficiency and cycle life, the flow radii of the positive electrolyte inlet and outlet channels must be smaller than those of the negative electrolyte inlet and outlet channels. The larger the ratio of the flow radii of the negative electrolyte inlet and outlet channels to that of the positive electrolyte inlet and outlet channels, the higher the battery performance and the better the cycle stability.

[0103] Further optimization is achieved when the flow radii of the positive electrolyte inlet distribution channel and the positive electrolyte outlet distribution channel are both smaller than the flow radii of the negative electrolyte inlet distribution channel and the negative electrolyte outlet distribution channel.

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A zinc-bromine single flow battery, characterized in that, The zinc-bromine single flow battery is a single battery or a battery pack formed by connecting two or more single batteries in series, and the single battery mainly comprises a negative electrode frame, a negative electrode arranged in a through hole in the middle of the negative electrode frame, a diaphragm, a positive electrode arranged in a through hole in the middle of the positive electrode frame, and a positive electrode frame which are sequentially stacked. The negative electrode frame is a rectangular flat plate with a through hole in the middle, and negative electrolyte inlet flow channels and negative electrolyte outlet flow channels are respectively arranged on opposite sides of the through hole on one side surface A of the flat plate, and a negative electrolyte inlet distribution flow channel connecting the negative electrolyte inlet flow channels and the middle through hole and a negative electrolyte outlet distribution flow channel connecting the negative electrolyte outlet flow channels and the middle through hole are arranged. The negative electrolyte inlet flow channels of each negative electrode frame are connected by a negative electrolyte inlet common flow channel, and the negative electrolyte outlet flow channels of each negative electrode frame are connected by a negative electrolyte outlet common flow channel. The flow radii of the positive electrolyte inlet flow channels and the positive electrolyte outlet flow channels are smaller than the flow radii of the negative electrolyte inlet flow channels and the negative electrolyte outlet flow channels.

2. The zinc-bromine single flow battery of claim 1, wherein, The flow radii of the positive electrolyte inlet distribution flow channels and the positive electrolyte outlet distribution flow channels are smaller than the flow radii of the negative electrolyte inlet distribution flow channels and the negative electrolyte outlet distribution flow channels.

3. The zinc-bromine single flow battery of claim 1, wherein, The flow radii of the positive electrolyte inlet flow channels and the positive electrolyte outlet flow channels are between 1mm and 3mm.

4. The zinc-bromine single flow battery of claim 3, wherein, The flow radii of the negative electrolyte inlet flow channels and the negative electrolyte outlet flow channels are between 4mm and 6mm.

5. The zinc-bromine single flow battery of claim 2, wherein, The flow radii of the positive electrolyte inlet distribution flow channels and the positive electrolyte outlet distribution flow channels are between 0.5mm and 1.5mm.

6. The zinc-bromine single flow battery of claim 5, wherein, The flow radii of the negative electrolyte inlet distribution flow channels and the negative electrolyte outlet distribution flow channels are between 2mm and 3mm.

7. The zinc-bromine single flow battery of any one of claims 1-6, wherein, The electrode materials of the negative electrode and the positive electrode are selected from graphite felt or carbon felt.

8. A method of improving coulombic efficiency and prolonging cycle life of a zinc-bromine single flow battery, characterized in that, The zinc-bromine single flow battery of any one of claims 1-7 is adopted.

Images