Novel electrochemical bipolar plate

Abstract

The utility model belongs to the technical field of electrochemistry, and particularly relates to a novel electrochemical bipolar plate, which can be used for extracting lithium by an electrochemical de-intercalation method and comprises a cathode plate and an anode plate, and the cathode plate and the anode plate are respectively composed of a polar plate outer frame body, a flow guide body frame and a polar plate electrode material. And the runners are designed on the polar plate frame body and the polar plate electrode material. The plate surface of the negative plate is also provided with a plurality of flow channels, including inclined flow channels, left and right vertical flow channels and upper and lower horizontal flow channels, the inclined flow channels form an included angle of 60 degrees and are continuously and crossly arranged, and the plate surface of the positive plate is provided with concave-convex complementary flow channels. The liquid flow channels with certain shapes and structures are designed on the cathode and anode plates, so that brine and lithium-rich liquid flow along the flow channels during lithium extraction and uniformly infiltrate the whole cathode and anode plates. Furthermore, polarization caused by lithium ion diffusion is reduced, and the lithium extraction current density and the lithium extraction efficiency of the bipolar plate are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of electrochemistry, in particular to a novel electrochemical bipolar plate. Background Art

[0002] Lithium, the lightest alkali metal element, is known as "white oil" and plays an indispensable role in the civilian and high-tech military fields. With the rapid development of portable electronics, electric vehicles and energy storage, the demand for lithium resources has increased year by year, and the supply of lithium resources will not be able to meet the demand in the future. Lithium resources mainly exist in minerals, brines and seawater, in the form of lithium compounds and ions respectively. With the mining of solid lithium mines, high-grade solid lithium ore is becoming less and less, and the cost of extracting lithium from ore is gradually increasing. Compared with the lithium resources in solid lithium mines, the mining of liquid lithium resources in the form of lithium ions in brine and seawater has a natural cost advantage.

[0003] Due to the complexity of the salt lake brine environment, different methods of lithium extraction are adopted. At present, some technologies for recovering lithium from brine have been developed, including carbonization, membrane separation, impregnation calcination, adsorption, solvent extraction, precipitation, etc. However, these methods are affected by factors such as climate, environmental pollution and selectivity loss, which will affect the effectiveness and feasibility of these methods. Compared with the above methods, electrochemical lithium extraction has the advantages of high lithium extraction efficiency, environmental friendliness, and high separation coefficient, and is gradually gaining attention.

[0004] At present, the main method of electrochemical lithium extraction is to use a rocking chair-type electrode lithium extraction system, that is, the positive electrode materials in the lithium-rich state and the lithium-poor state constitute the anode and cathode plates, with an anion membrane in the middle, and the anode and cathode chambers composed of the anode and cathode plates and the anion membrane are filled with brine and lithium-rich liquid, thus forming an electrochemical lithium extraction unit. During the entire lithium extraction process, there is a complete electrochemical reaction. Therefore, the process will be affected by the charge transfer step of the electrode itself and the mass transfer step of lithium ions in the liquid phase. The premise for lithium ions to participate in the electrochemical reaction in the electrode is that they migrate smoothly to the electrode surface in the liquid phase. This means that the infiltration and flow of the solution on the entire electrode material part of the electrode plate have a great influence on the entire lithium extraction process.

[0005] At present, most of the electrodes used in electrochemical lithium extraction are directly coated with anion membranes to form lithium extraction units. This will result in the situation that when brine or lithium-rich liquid enters the cathode and anode chambers, it cannot well infiltrate the plates, resulting in the restriction of lithium ions entering the electrode materials to participate in the electrode reaction, which in turn affects a series of performance indicators of the lithium extraction unit, such as lithium extraction current density, lithium extraction capacity, and lithium extraction efficiency.

[0006] In view of this, this application is hereby filed. Utility Model Content

[0007] The utility model aims to provide a novel electrochemical bipolar plate to solve the problem in the above-mentioned background technology that brine and lithium-rich liquid cannot well infiltrate the plates in the cathode and anode chambers, thus affecting the lithium extraction performance.

[0008] In order to achieve the above-mentioned purpose, the utility model provides a novel electrochemical bipolar plate, and the technical scheme is as follows:

[0009] According to a novel electrochemical bipolar plate in a specific embodiment of the utility model, the novel electrochemical bipolar plate includes a cathode plate and an anode plate, and both the cathode and anode plates are composed of three parts: an outer frame of the plate, a flow conducting frame and an electrode material of the plate. The flow channel is designed on both the plate frame and the electrode material of the plate.

[0010] According to a new electrochemical bipolar plate in a specific embodiment of the utility model, the outer frame is made of plastic or rubber, the cathode and anode plate electrode materials are lithium iron phosphate, lithium manganese oxide, or a ternary material, and the flow conductor frame is made of titanium mesh, nickel foam, or copper mesh.

[0011] According to a novel electrochemical bipolar plate in a specific embodiment of the utility model, the flow channels on the front and back sides of the cathode plate are designed to be the same; the flow channels on the front and back sides of the anode plate are designed to be the same.

[0012] According to a novel electrochemical bipolar plate in a specific embodiment of the utility model, the flow channels of the cathode plate and the anode plate outer frame are designed to be concave and convex complementary.

[0013] According to a novel electrochemical bipolar plate in a specific embodiment of the utility model, the flow channel design of the outer frame of the anode and cathode plates is composed of at least two water holes, and each water hole is connected to the water hole by at least one guide groove below.

[0014] Optionally, the number of the water holes may be 2, 4, or 6.

[0015] Optionally, the number of the guide grooves may also be 2-4.

[0016] According to a novel electrochemical bipolar plate in a specific embodiment of the utility model, the flow channel design of the plate material part of the anode and cathode plates is composed of inclined flow channels, vertical flow channels and horizontal flow channels.

[0017] According to a novel electrochemical bipolar plate of a specific embodiment of the utility model, the inclined flow channel is composed of a left inclined flow channel and a right inclined flow channel, and the left and right inclined flow channels are arranged at an angle of 60 degrees and are continuously cross-arranged. The vertical flow channel is distributed on the left and right sides of the electrode material part of the plate, and the horizontal flow channel is distributed on the upper and lower sides of the electrode material part of the plate.

[0018] Optionally, the angle between the left and right oblique channels can also be 45°.

[0019] According to a novel electrochemical bipolar plate of a specific embodiment of the utility model, the left and right inclined flow channels are cross-arranged to form a diamond grid, wherein there are 4-16 grids per square decimeter. The horizontal and vertical flow channels are each two on a single side of the plate.

[0020] According to a novel electrochemical bipolar plate in a specific embodiment of the utility model, the diameter of the water hole is 20-50 mm, the width of the guide groove is 5-15 mm, and the depth is 0.5 times the width.

[0021] According to a novel electrochemical bipolar plate in a specific embodiment of the utility model, the width of the inclined, horizontal and vertical flow channels is 5-15 mm, and the depth is 0.5 times the width.

[0022] Compared with the prior art, the beneficial effects of the utility model are:

[0023] 1. The utility model provides a novel electrochemical bipolar plate with flow channel design in both the plate outer frame and the plate electrode material part. The lithium extraction unit design composed of the plate can make brine and lithium-rich liquid flow more evenly in the anode and cathode chambers, thereby fully infiltrating the entire plate electrode material part, so that the liquid phase mass transfer of lithium ions on the surface of the electrode material proceeds smoothly, thereby improving the lithium extraction performance of the lithium extraction unit.

[0024] 2. The utility model provides a novel electrochemical bipolar plate in which the flow channel is designed inside the plate itself, which does not require additional structures such as a water distribution network, thereby reducing the redundancy of the lithium extraction unit and reducing the manufacturing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 A schematic diagram of the flow channels of the cathode and anode plates of an embodiment of the utility model (the anode plate is on the left);

[0027] Figure 2 For the utility model embodiment Figure 1 Cross-section view in the AA direction;

[0028] Figure 3 For the utility model embodiment Figure 1 Cross-section along the middle BB direction;

[0029] Figure 4 For the utility model embodiment Figure 1 Cross-sectional view in the mid-CC direction;

[0030] Figure 5 For the utility model embodiment Figure 1 Cross-section in the middle DD direction;

[0031] Figure 6 A schematic diagram of the flow channel of the electrode material portion of the plate of the embodiment of the utility model;

[0032] Figure 7 A schematic diagram of the flow channel of the outer frame of the cathode plate of the embodiment of the utility model; DETAILED DESCRIPTION

[0033] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Generally, the components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0034] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0035] In the description of the present utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate the orientation or position relationship based on the orientation or position relationship shown in the accompanying drawings, or the orientation or position relationship in which the utility model product is usually placed when in use, which is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0036] In addition, the terms "parallel", "vertical", etc. do not mean that the components must be absolutely parallel or vertical, but can be slightly tilted. For example, "parallel" only means that its direction is more parallel than "vertical", and does not mean that the structure must be completely parallel, but can be slightly tilted.

[0037] In addition, the terms "horizontal", "vertical", "overhanging" and the like do not mean that the components are required to be absolutely horizontal or overhanging, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0038] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] See also Figure 1-6 , an embodiment provided by the utility model:

[0040] A novel electrochemical bipolar plate, such as Figure 1 As shown, the novel electrochemical bipolar plate of the utility model is divided into two types of plates, namely, anode plates and cathode plates. Both the anode plates and cathode plates are composed of two parts, namely, a plate electrode material part 1, a plate outer frame 2, and a fluid frame 3. Among them, the flow channel is designed on the plate electrode material part 1 and the plate outer frame 2 of the anode and cathode plates.

[0041] like Figure 6 As shown, the electrode material 1 of the cathode plate is composed of a horizontal channel 11, a vertical channel 12, a left oblique channel 13 and a right oblique channel 14. The left oblique channel 13 and the right oblique channel 14 are arranged at an angle of 60° and are continuously cross-arranged. The vertical channel 12 is distributed on the left and right sides of the electrode material 1 of the cathode plate, and the horizontal channel 11 is distributed on the upper and lower sides of the electrode material 1 of the cathode plate. The outer frame 2 of the cathode plate is provided with a guide groove 21 and a water hole 22. Figure 7 As shown, the cathode plate outer frame 2 has two water holes on the top and bottom, and the water holes 22 on the upper left, right and lower left of the outer frame 2 are connected to three guide grooves 21, which are connected to the plate electrode material part 1. The flow channels on both sides of the cathode plate are designed to be mirror-symmetrical.

[0042] like Figure 1 As shown, the flow channel design of the anode plate is mirror-symmetrical with that of the cathode plate. That is, the arrangement of the horizontal flow channel 11, the vertical flow channel 12, the left oblique flow channel 13 and the right oblique flow channel 14 of the electrode material part 1 of the plate is the same as that of the cathode plate. The outer frame part 2 of the plate also has two water holes 22 on the top and bottom, and the guide groove 21 is arranged below the water holes 22 on the upper left and lower right, and is connected to the electrode material part 1 of the plate.

[0043] like Figure 6As shown, the flow channel design of the electrode material part 1 of the plate is formed by pressing a stainless steel mesh with the same shape and size as the flow channel of the plate material part. The width of the horizontal flow channel 11, the vertical flow channel 12, the left oblique flow channel 13 and the right oblique flow channel 14 are all 8mm, the depth is 4mm, and the cross section is as follows Figure 2 , 3 , 4, and 5. The left oblique flow channel 13 and the right oblique flow channel 14 form a diamond grid with an angle of 60°, and the density of the grid is 16 per square decimeter. Figure 7 As shown, the diameter of the water hole 22 of the plate outer frame 2 is 50 mm, the width of the guide groove 21 is 8 mm, the depth is 4 mm, and the cross-section is also semicircular.

[0044] like Figure 1 As shown, the guide grooves 21 of the outer frame part 2 of the cathode and anode plates are designed to be mirror-symmetrical and complement each other. The cathode and anode plates and the anion membrane are aligned and tightly fitted, and different guide grooves 21 are designed to form the cathode chamber and the anode chamber. Brine and lithium-rich liquid are respectively passed into the cathode chamber and the anode chamber through the water holes 22 of the cathode plate with and without guide grooves 21, and then lithium insertion reaction and lithium removal reaction occur respectively. Through the flow channel design of the electrode material part 1 of the plate, the brine and lithium-rich liquid entering the cathode and anode chambers can fully infiltrate the entire plate and flow evenly on the plate, and when the brine and lithium-rich liquid pass through the bifurcation of the flow channel, the liquids will collide and mix to form turbulence, which further homogenizes the liquids.

[0045] Comparative Example

[0046] Different from the embodiment, the battery material part of the lithium extraction plate of the comparative example does not have any flow channel design, and the coated anode and cathode plates and anion membrane are directly used to form a lithium extraction unit. In order to ensure that the brine and lithium-rich liquid enter the anode and cathode chambers normally, the flow channel design of the outer frame part of the plate of the comparative example is consistent with that of the embodiment.

[0047] The lithium extraction performance of the lithium extraction unit composed of the lithium extraction plates of the above embodiments and comparative examples was tested by experiments. The specific method is to mix the lithium iron phosphate electrode material, Ketjen black conductive agent, and polyvinylidene fluoride in a mass ratio of 80:10:10, add N-methylpyrrolidone (NMP) organic solvent, grind and adjust to a slurry, apply it on the titanium mesh frame including the outer frame, and dry it at 80°C for 12h. The embodiment performs flow channel pressing, and the comparative example does not do any treatment. The dried electrode is used as the anode, and the graphite plate of the same size is used as the cathode, and is placed in a certain concentration of NaCl solution, and a voltage of 1.2v is applied to perform electrochemical lithium removal of 20% and 80% of the total capacity to obtain an anode plate and a cathode plate, respectively. A lithium extraction unit is composed of 3 anode plates, 2 cathode plates, and 3 anion membranes. In the power supply mode of constant current first and constant voltage later, the lithium extraction performance test of 50% of the total capacity is performed at different flow rates, different initial current densities, and different brine lithium ion concentrations.

[0048] Table 1 Lithium extraction performance of examples and comparative examples

[0049]

[0050] It can be seen from the data in the above table that the lithium extraction plate described in the present application, through a suitable flow channel design, the lithium extraction unit design composed of which can make the brine and the lithium-rich liquid flow more evenly in the anode and cathode chambers, and then fully infiltrate the entire electrode material part of the plate, so that the liquid phase mass transfer of lithium ions on the surface of the electrode material proceeds smoothly, thereby improving the lithium extraction performance of the lithium extraction unit.

[0051] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A novel electrochemical bipolar plate, characterized in that: The novel electrochemical bipolar plate comprises a cathode plate and an anode plate. Both the cathode and anode plates are composed of three parts: an outer plate frame, a flow conductor frame and a plate electrode material. The flow channels are designed on both the plate frame and the plate electrode material.

2. A novel electrochemical bipolar plate according to claim 1, characterized in that: The outer frame is made of plastic or rubber, the cathode and anode electrode materials are lithium iron phosphate, lithium manganese oxide, or a ternary material, and the flow conductor frame is made of titanium mesh, nickel foam, or copper mesh.

3. A novel electrochemical bipolar plate according to claim 2, characterized in that: The flow channels on the front and back sides of the cathode plate are designed the same; the flow channels on the front and back sides of the anode plate are designed the same.

4. A novel electrochemical bipolar plate according to claim 3, characterized in that: The flow channels of the cathode plate and the anode plate outer frame are designed to be concave and convex complementary.

5. A novel electrochemical bipolar plate according to claim 4, characterized in that: The flow channel design of the outer frame of the anode and cathode plates is composed of at least two water holes, and each water hole is connected to the water hole by at least one guide groove below.

6. A novel electrochemical bipolar plate according to claim 4, characterized in that: The flow channel design of the plate material part of the anode and cathode plates consists of an inclined flow channel, a vertical flow channel and a horizontal flow channel.

7. A novel electrochemical bipolar plate according to claim 6, characterized in that: The inclined flow channel is composed of a left inclined flow channel and a right inclined flow channel. The left and right inclined flow channels form an angle of 60° and are continuously cross-arranged. The vertical flow channel is distributed on the left and right sides of the electrode material part of the plate, and the horizontal flow channel is distributed on the upper and lower sides of the electrode material part of the plate.

8. A novel electrochemical bipolar plate according to claim 7, characterized in that: The left oblique flow channel and the right oblique flow channel are cross-arranged to form a diamond grid, wherein there are 4-16 grids per square decimeter, and the horizontal and vertical flow channels are respectively two on a single side of the electrode plate.

9. A novel electrochemical bipolar plate according to claim 5, characterized in that: The diameter of the water hole is 20-50 mm, the width of the guide groove is 5-15 mm, and the depth is 0.5 times the width.

10. A novel electrochemical bipolar plate according to claim 6, characterized in that: The width of the inclined, horizontal and vertical flow channels is 5-15 mm, and the depth is 0.5 times the width.

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