A zinc-bromine single flow battery

Abstract

The present invention relates to the technical field of liquid flow battery energy storage, a zinc-bromine single liquid flow battery, wherein the cathode electrode frame is a flat plate, a groove is provided in the middle of the upper surface of the flat plate, a hollow through hole for accommodating a porous cathode is provided in the middle of the bottom surface of the groove, a diaphragm is placed in the groove, and the edges of the lower surface of the diaphragm are in contact with the edges of the bottom surface of the groove; the anode electrode frame is a flat plate, a groove is provided in the middle of the upper surface of the flat plate, a hollow through hole for accommodating a porous anode is provided in the middle of the bottom surface of the groove, a bipolar plate is placed in the groove, and the edges of the lower surface of the bipolar plate are in contact with the edges of the bottom surface of the groove; the diaphragm is a porous diaphragm with a film thickness of 200-1200 microns. The diaphragm is placed in the groove of the cathode electrode frame and is completely sealed inside the battery stack, which can effectively prevent the electrolyte from leaking outward through the cut surface of the diaphragm, and eliminate the safety hazard of battery short circuit caused by the electrolyte conducting each section.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid flow battery energy storage, and in particular to the field of zinc-bromine single liquid flow battery. Background Art

[0002] The zinc-bromine single-flow battery is a high-efficiency, long-life flow battery energy storage technology with high energy density, simple and easy-to-operate device, and the positive electrode active material is enclosed inside the battery stack, which can not only reduce the use of circulation pumps and liquid storage barrels, reduce the cost of the battery stack, but also effectively prevent bromine pollution. It is mainly used in fields such as power grid peak regulation, wind power and solar energy and other renewable energy power generation. The existing zinc-bromine single-flow battery is sealed between the electrode frame and the bipolar plate, and between the electrode frame and the diaphragm by a sealing gasket, which has the following disadvantages: Due to the characteristics of the zinc-bromine single-flow battery diaphragm, when the zinc-bromine flow battery is running, the electrolyte will penetrate horizontally through the diaphragm to the outside of the battery stack, and the electrolyte outside the battery stack will cause each battery to short-circuit, posing a safety hazard. In addition, the use of sealing gaskets will greatly increase the cost of zinc-bromine flow batteries. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a zinc-bromine single-flow battery. The electrode frame material is made of polyvinyl chloride, which is easy to process. Grooves are provided on the surface of the cathode electrode frame and the anode electrode frame of each section, and the diaphragm and the bipolar plate are placed respectively. Since the diaphragm and the bipolar plate are placed in the grooves, there is no need to use a sealing gasket for sealing, and the electrolyte can also be effectively inhibited from penetrating to the outside of the battery stack through the diaphragm.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A zinc-bromine single flow battery comprises two or more single cells stacked sequentially from bottom to top, wherein the single cell comprises a cathode electrode frame, a porous cathode, a diaphragm, an anode electrode frame, and a porous anode, and a bipolar plate is arranged between adjacent single cells.

[0006] The cathode electrode frame is a flat plate, a groove is provided in the middle of the upper surface of the flat plate, a hollow through hole for accommodating the porous cathode is provided in the middle of the bottom surface of the groove, the diaphragm is placed in the groove, and the edges around the lower surface of the diaphragm are in contact with the edges around the bottom surface of the groove;

[0007] The anode electrode frame is a flat plate, a groove is provided in the middle of the upper surface of the flat plate, a hollow through hole for accommodating the porous anode is provided in the middle of the bottom surface of the groove, the bipolar plate is placed in the groove, and the edges of the lower surface of the bipolar plate are in contact with the edges of the bottom surface of the groove;

[0008] The diaphragm is a porous diaphragm with a thickness of 200-1200 microns.

[0009] A cathode electrolyte outlet flow channel and a cathode electrolyte inlet flow channel are respectively provided above and below the electrode frame surface on the side where the cathode electrode frame groove is located; an anode electrolyte outlet flow channel and an anode electrolyte inlet flow channel are respectively provided above and below the electrode frame surface on the side away from the groove of the anode electrode frame.

[0010] 12 to 18 through holes are respectively arranged around the edges of the cathode and anode electrode frames to serve as bolt holes for fixing the battery stack.

[0011] Cover sheets are provided on the electrolyte inlet flow channel and the electrolyte outlet flow channel to prevent the flow channel from being blocked when the diaphragm is compressed and the bipolar plate from being broken when the bipolar plate is compressed.

[0012] The electrode frame material is polyvinyl chloride.

[0013] When the battery is assembled, the cathode electrode frames and the anode electrode frames are placed alternately in sequence, and the sides of the cathode electrode frames and the anode electrode frames with the electrolyte inlet and outlet flow channels are placed opposite to each other.

[0014] The depth of the groove on the cathode electrode frame is less than the thickness of the diaphragm before assembly; the depth of the groove on the anode electrode frame is less than the thickness of the bipolar plate before assembly;

[0015] After the battery is assembled, the depth of the groove on the cathode electrode frame is equal to the thickness of the diaphragm; the depth of the groove on the anode electrode frame is equal to the thickness of the bipolar plate. The present invention adopts the above technical solution, and compared with the prior art, has the following technical effects:

[0016] The diaphragm is placed in the groove of the cathode electrode frame and is completely sealed inside the battery stack, which can effectively prevent the electrolyte from leaking outward through the cut surface of the diaphragm, eliminating the safety hazard of battery short circuit caused by the electrolyte conducting through each section. At the same time, since the diaphragm and bipolar plate are sealed inside the battery stack, there is no need to use sealing gaskets to seal between the electrode frame and the diaphragm, and between the electrode frame and the bipolar plate, which simplifies the components of the battery stack and reduces the cost of the battery stack. The battery structure omits the sealing gasket, making it thinner. The battery polarization is reduced, the internal resistance of the battery is reduced, and the power density is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The electrode frame structure of the present invention comprises: 1- cathode electrode frame, 2- anode electrode frame,

[0018] Figure 2 Schematic diagram of battery assembly of the present invention, 1- cathode electrode frame, 2- anode electrode frame, 3- electrode, 4- bipolar plate, 5- membrane

[0019] Figure 3 Schematic diagram of conventional zinc-bromine single flow battery assembly

[0020] 1- cathode electrode frame, 2- anode electrode frame, 3- electrode, 4- bipolar plate, 5- membrane, 6- sealing gasket DETAILED DESCRIPTION

[0021] Example

[0022] The sealing design structure of the zinc-bromine single flow battery provided by the present invention is as follows Figure 1 The schematic diagram of the battery stack assembly is shown in Figure 2 As shown. In the middle of the electrode frame, a hollow through hole is provided for placing the porous electrode. On the surface of the cathode electrode frame, a groove is provided for placing the diaphragm. On the surface of the groove of the cathode electrode frame, a cathode electrolyte outlet flow channel and a cathode electrolyte inlet flow channel are provided on the upper and lower sides of the rectangular through hole respectively. On the surface of the anode electrode frame, a groove is provided for placing the bipolar plate. On the surface of the anode electrode frame away from the groove, an anode electrolyte outlet flow channel and an anode electrolyte inlet flow channel are provided on the upper and lower sides of the through hole respectively. During assembly, the porous electrode is placed in the through hole in the middle of the cathode electrode frame and the anode electrode frame. To ensure the compression ratio, the thickness of the porous electrode is slightly higher than that of the cathode electrode frame and the anode electrode frame. A diaphragm is placed in the groove of the cathode electrode frame, with a thickness of 900 microns and a depth of 800 microns. A bipolar plate is placed in the groove of the anode electrode frame, with a thickness of 1 mm and a depth of 1 mm. The diaphragm and the bipolar plate are in contact with the porous electrode; the cathode electrode frame and the anode electrode frame are placed alternately in turn, and the sides of the cathode electrode frame and the anode electrode frame with the flow channel are placed opposite each other. After the battery is assembled, it runs 300 cycles at 40 mA / cm2, and the battery voltage efficiency is 89%.

[0023] Comparative Example

[0024] like Figure 3 The conventional zinc-bromine single-flow battery structure consists of two single cells connected in series, and the single cells are stacked in sequence, including positive electrode current collecting plate, sealing gasket, positive electrode liquid flow frame, sealing gasket, positive electrode, membrane, negative electrode, sealing gasket, negative electrode liquid flow frame, and negative electrode current collecting plate. After the battery is assembled, it runs 300 cycles at 40mA / cm2, and the battery voltage efficiency is 85%.

[0025] Since the diaphragm and bipolar plates are sealed inside the battery stack, there is no need to use sealing gaskets to seal between the electrode frame and the diaphragm, and between the electrode frame and the bipolar plates. The battery structure omits the sealing gasket, which makes its thickness thinner, reduces battery polarization, reduces battery internal resistance, and significantly improves battery voltage efficiency.

Claims

1. A zinc-bromine single flow battery, comprising two or more single cells stacked sequentially from bottom to top, wherein the single cell comprises a cathode electrode frame, a porous cathode, a diaphragm, an anode electrode frame, and a porous anode, and a bipolar plate is provided between adjacent single cells, characterized in that: The cathode electrode frame is a flat plate, a groove is provided in the middle of the upper surface of the flat plate, a hollow through hole for accommodating the porous cathode is provided in the middle of the bottom surface of the groove, the diaphragm is placed in the groove, and the edges around the lower surface of the diaphragm are in contact with the edges around the bottom surface of the groove; The anode electrode frame is a flat plate, a groove is provided in the middle of the upper surface of the flat plate, a hollow through hole for accommodating the porous anode is provided in the middle of the bottom surface of the groove, the bipolar plate is placed in the groove, and the edges of the lower surface of the bipolar plate are in contact with the edges of the bottom surface of the groove; The diaphragm is a porous diaphragm with a thickness of 200-1200 microns; The depth of the groove on the cathode electrode frame is less than the thickness of the diaphragm before assembly; the depth of the groove on the anode electrode frame is less than the thickness of the bipolar plate before assembly; After the battery is assembled, the depth of the groove on the cathode electrode frame is equal to the thickness of the diaphragm; the depth of the groove on the anode electrode frame is equal to the thickness of the bipolar plate; 12 to 18 through holes are respectively arranged around the edges of the cathode and anode electrode frames to serve as bolt holes for fixing the battery stack.

2. The zinc-bromine single flow battery according to claim 1, characterized in that: A cathode electrolyte outlet flow channel and a cathode electrolyte inlet flow channel are respectively provided above and below the electrode frame surface on the side where the cathode electrode frame groove is located; an anode electrolyte outlet flow channel and an anode electrolyte inlet flow channel are respectively provided above and below the electrode frame surface on the side away from the groove of the anode electrode frame.

3. The zinc-bromine single flow battery according to claim 1, characterized in that: Cover sheets are provided on the electrolyte inlet flow channel and the electrolyte outlet flow channel to prevent the flow channel from being blocked when the diaphragm is compressed and the bipolar plate from being broken when the bipolar plate is compressed.

4. The zinc-bromine single flow battery according to claim 1, characterized in that: The electrode frame material is polyvinyl chloride.

5. The zinc-bromine single flow battery according to claim 1, characterized in that: When the battery is assembled, the cathode electrode frames and the anode electrode frames are placed alternately in sequence, and the sides of the cathode electrode frames and the anode electrode frames with the electrolyte inlet and outlet flow channels are placed opposite to each other.

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