Metal-air battery single cell electrolyte circulation channel and stack electrolyte circulation system

Abstract

The present invention discloses an electrolyte circulation channel for a metal-air battery single cell and an electrolyte circulation system for a battery stack. The electrolyte circulation channel arranges the water inlet at the bottom of the reaction cavity. The electrolyte enters from the bottom of the reaction cavity, then gradually fills the reaction cavity, overflows to the reflux cavity through the top of the reaction cavity, and finally flows out from the water outlet, realizing the circulation of the electrolyte. Between the battery stacks formed by cascading and stacking multiple metal-air battery single cells, the electrolyte circulation system is directly connected through the water inlet and the water outlet. Only the outermost two ends of the battery stack need to be connected to the electrolyte delivery device and the electrolyte recovery device through pipelines, making the electrolyte pipeline of the entire battery stack simpler and reducing the internal loss of the battery.

Description

Technical Field

[0001] The present invention relates to the technical field of metal-air batteries, and particularly relates to an electrolyte circulation channel for a metal-air battery monomer and an electrolyte circulation system for a battery stack. Background Art

[0002] A metal-air battery monomer is a chemical power source that uses oxygen in the air as the positive electrode active material, a metal as the negative electrode active material, and a conductive solution as the electrolyte, and generates electrical energy through a chemical reaction under the catalysis of a positive electrode catalyst.

[0003] In order to ensure the continuous and stable discharge reaction of the metal-air battery and flush and remove the residues generated during the discharge reaction in the reaction cavity, it is necessary to ensure the circulating flow of the electrolyte between the positive and negative electrodes of the battery. Currently, the disadvantages of the metal-air battery electrolyte circulation method are prominently manifested in the following five aspects: (1) The flow rate and distribution of the electrolyte in the reaction cavity of the battery monomer are uneven, resulting in uneven discharge reactions in the reaction cavity; (2) The problem of poor slag discharge; (3) When the input electrolyte is in a parallel connection mode, the pipeline connection of the distributor is complex and difficult to maintain; (4) When the input electrolyte is in a series connection mode, the liquid levels between the individual cells in the battery stack are inconsistent during operation, and some cells cannot operate in a circulating manner during operation because the liquid level in the reaction cavity is lower than the water outlet; (5) Since the electrolytes at the input end and the output end are both in series and parallel connection modes, partial power loss will occur due to liquid flow short circuit. Summary of the Invention

[0004] Aiming at the defects in the prior art, the present invention provides an electrolyte circulation channel for a metal-air battery monomer and an electrolyte circulation system for a battery stack to solve the problems existing in the existing electrolyte circulation working mode of the metal-air battery monomer, such as incomplete electrode reaction due to uneven electrolyte flow rate and distribution, complex pipeline connection, difficult slag discharge, inconsistent rise of the electrolyte liquid level in the reaction cavities of the individual cells in the battery stack during series input, and further increased loss of the electrolyte in the battery stack at the input end and the output end due to liquid flow short circuit.

[0005] The present invention solves the above technical problems through the following technical means:

[0006] An electrolyte circulation channel for a metal-air battery monomer, the metal-air battery monomer includes a monomer frame, the battery monomer electrolyte circulation channel is arranged in the monomer frame, and the electrolyte circulation channel includes a reaction cavity arranged in the monomer frame and a water inlet and a water outlet arranged on the monomer frame and communicating with the inside of the reaction cavity;

[0007] The top of the reaction cavity is communicated with a reflux cavity through an overflow port, and both the water inlet and the water outlet are arranged at the bottom of the reaction cavity;

[0008] After the electrolyte enters the reaction cavity from the water inlet, it flows through the reflux cavity through the overflow port at the top and then flows out from the water outlet.

[0009] Furthermore, the reflux cavities are arranged on both sides of the reaction cavity, and the two groups of water outlets are respectively located at the bottom of the reflux cavities.

[0010] Furthermore, the water inlet is arranged in the middle of the bottom of the reaction cavity.

[0011] Furthermore, the bottom of the reaction cavity is a funnel-shaped slope, and the lowest position of the slope is docked to the water inlet.

[0012] Furthermore, the electrolyte circulation channel further includes a breathing port arranged on the monomer frame. The breathing port is located above the reflux cavity and is communicated with the inside of the reaction cavity.

[0013] Furthermore, an overflow platform with a tongue structure is horizontally arranged between the overflow port and the reflux cavity.

[0014] Furthermore, a superhydrophobic coating is provided on the contact surface of the monomer frame in contact with the electrolyte. The superhydrophobic coating is coated with a superhydrophobic material resistant to high temperature and strong alkali to prevent peeling from the monomer frame due to strong alkali corrosion of the electrolyte.

[0015] On the other hand, the present invention also provides an electrolyte circulation system for a metal-air battery stack. The stack includes at least two metal-air battery monomers installed in a cascaded and stacked manner. The monomer frame of the metal-air battery monomer is provided with the aforementioned electrolyte circulation channel. The electrolyte circulation system includes at least two such electrolyte circulation channels. The water inlets and outlets of the electrolyte circulation channels are both arranged through the monomer frame along the stacking direction of the monomer frames. The water inlets between adjacent monomer frames are coaxially docked and communicated one by one. The water inlet at one end outside the stack is connected to an electrolyte delivery device. The water inlet at the other end outside the stack serves as a slag discharge port and is connected to a residue recovery device through a valve. The water outlet at the outermost side of the stack is connected to an electrolyte recovery device.

[0016] Furthermore, the top of the water inlet is communicated with the reaction cavity, and the top of the water outlet is communicated with the reflux cavity.

[0017] Furthermore, a flow disturbing plate for disturbing the liquid flow is provided in the water inlet.

[0018] The beneficial effects of the present invention are embodied in:

[0019] The electrolyte circulation channel of the metal-air battery monomer of the present invention arranges the water inlet at the bottom of the reaction cavity. The electrolyte enters from the bottom of the reaction cavity, then gradually fills the reaction cavity, and flows out from the outlet through the overflow port and overflow platform at the top of the reaction cavity to the reflux cavity, realizing the circulation of the electrolyte. The electrolyte fully immerses the negative and positive electrodes of the battery, enabling the discharge reaction of the electrode material to be more complete and making more efficient use of the electrode material to participate in the discharge reaction. The overflow platform (platform tongue) at the top of the reaction cavity is coated with a superhydrophobic material that is resistant to high temperature and strong alkali. When the electrolyte falls onto the reflux cavity through the overflow platform, the liquid forms intermittent discontinuous flow and conducts unidirectionally, increasing the resistance at the outlet of the single battery and greatly reducing the power loss caused by the liquid flow short circuit at the output end during the cascading of single batteries. The electrolyte circulation system is directly connected between the stacks after multiple metal-air battery monomers are cascaded and stacked through the water inlet and outlet. Only the electrolyte conveying equipment and electrolyte recovery equipment need to be connected through pipelines at the outermost ends of the stack, making the electrolyte pipeline of the entire stack simpler.

[0020] In summary, starting from the structural design and materials used, the present invention has invented a circulation system for the electrolyte of the metal-air battery monomer, which solves the five aspects of problems in the electrolyte circulation system of the metal-air battery monomer and its stack, improves the utilization rate of the electrode material, makes the layout of the electrolyte circulation pipeline of the stack simpler, more convenient for slag discharge, and ensures the continuous circulation of the electrolyte inside the metal-air battery. Description of the Drawings

[0021] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0022] Figure 1 It is a schematic structural diagram of the metal-air battery monomer in Embodiment 1;

[0023] Figure 2 It is an exploded schematic structural diagram of the metal-air battery monomer in Embodiment 1;

[0024] Figure 3 It is a schematic structural diagram of the monomer frame in Embodiment 1 Figure 1 ;

[0025] Figure 4 It is a schematic structural diagram of the monomer frame in Embodiment 1 Figure 2 ;

[0026] Figure 5 It is a schematic diagram of the positions of the reaction cavity and the reflux cavity inside the monomer frame in Embodiment 1;

[0027] Figure 6 Schematic diagram of the electrolyte flow path inside the metal-air battery monomer in Embodiment 1;

[0028] Figure 7 Schematic diagram of the stack structure of the cascaded and stacked metal-air battery monomers in Embodiment 2.

[0029] In the accompanying drawings,

[0030] 1 - monomer frame, 100 - reaction window, 102 - reaction cavity, 111 - water inlet, 112 - water outlet, 113 - spoiler, 114 - breathing port, 115 - overflow port, 116 - reflux cavity, 117 - overflow platform, 131 - fixing through hole, 2 - positive electrode, 22 - ventilation plate, 3 - negative electrode. Detailed implementation manners

[0031] The embodiments of the technical solutions of the present invention will be described in detail below with reference to the accompanying drawings. The following embodiments are only used to illustrate the technical solutions of the present invention more clearly, and therefore are only examples and cannot be used to limit the protection scope of the present invention.

[0032] It should be noted that unless otherwise specified, the technical terms or scientific terms used in this application should have the ordinary meanings understood by those skilled in the art to which the present invention belongs.

[0033] Embodiment 1

[0034] See Figures 1 to 5, the metal-air battery cell in the illustration is a specific implementation example using the electrolyte circulation channel of the present invention. The metal-air battery cell in this embodiment includes a cell frame 1, a positive electrode 2, and a negative electrode 3, and the negative electrode 3 is inserted into the cell frame 1. The electrolyte circulation channel of the metal-air battery cell includes a reaction cavity 102 provided inside the cell frame 1 and a water inlet 111 and a water outlet 112 provided on the cell frame 1 and communicating with the inside of the reaction cavity 102. Reaction windows 100 are respectively provided at positions corresponding to both sides of the cell frame 1 in the reaction cavity 102. The positive electrode 2 is tightly assembled on the side of the cell frame 1 through a ventilation plate 22 to cover and seal the reaction window 100. Two vertical reflux cavities 116 are provided on both sides of the reaction cavity 102. The top of the reaction cavity 102 is overflow-connected to the top of the reflux cavity 116. The water inlet 111 is provided on the cell frame 1 corresponding to the middle of the bottom of the reaction cavity 102. Two groups of water outlets 112 are respectively provided on the cell frame 1 corresponding to the bottoms of the two reflux cavities 116. The electrolyte in the reaction cavity 102 enters the reaction cavity 102 from the water inlet 111 and flows between the negative electrode 3 and the positive electrode 2. After the reaction cavity 102 is filled with electrolyte and the discharge reaction areas of the negative electrode 3 and the positive electrode 2 are completely immersed, it overflows from the top of the reaction cavity 102 to the reflux cavity 116 and flows out from the water outlet 112.

[0035] In addition, a breathing port 114 is further provided on the cell frame 1 corresponding to the reaction cavity 102 or the reflux cavity 116. During the rising or falling process of the electrolyte liquid level inside the reaction cavity 102, it is used to keep the liquid level pressure inside the reaction cavity 102 balanced with the outside atmospheric pressure, avoiding deformation and damage of the positive electrode 2 due to the pressure change inside the reaction cavity 102. At the same time, the gas generated during the operation of the battery can also be collected through this breathing port 114. The setting position of the breathing port 114 should be higher than the position of the overflow port and is located above the reflux cavity 116 to avoid leakage of electrolyte from the breathing port 114. The bottom of the reaction cavity 102 is set as a funnel-shaped slope, and the lowest position of the slope is docked to the water inlet. In this way, the large-particle residues generated by the reaction inside the reaction cavity will be concentrated and precipitated at the bottom of the reaction cavity, facilitating unified collection after the reaction.

[0036] See Figure 6, inside the metal-air battery cell of this embodiment, the electrolyte enters the interior of the reaction cavity 102 from the water inlet 111 at the middle bottom of the cell frame 1. As the electrolyte is continuously supplied, the liquid level of the electrolyte inside the reaction cavity 102 gradually rises until the liquid level reaches the topmost part of the negative electrode positioning baffles on both sides of the reaction cavity 102. At this time, the space between the positive electrode and the negative electrode is completely filled with the electrolyte, ensuring that the electrode materials fully participate in the discharge reaction. Further, as the electrolyte is continuously supplied, the electrolyte in the reaction cavity 102 overflows into the two side reflux cavities 116 through the overflow port 115 at the top and is recycled from the water outlet 112 through the reflux cavity 116. During the whole process, the liquid level inside the reaction cavity can communicate with the outside of the reaction cavity through the breathing port 114, ensuring that the pressure inside the reaction cavity is balanced with the external atmospheric pressure. At the same time, referring to Figure 5 and Figure 6 , a tongue structure horizontally extending towards the reflux cavity is provided between the overflow port 115 and the reflux cavity 116 as an overflow platform 117. After the electrolyte flows through the edge of the overflow platform 117, it falls into the reflux cavity 116 in the form of intermittent droplets and conducts unidirectionally, increasing the resistance of the water outlet of the single battery, thereby reducing the power loss caused by liquid flow short circuit at the output end of the cascaded battery.

[0037] Further, the cell frame 1 is generally made of plastic material, and a superhydrophobic material with high temperature and strong alkali resistance is sprayed on the plastic surfaces in contact with the electrolyte inside the cell frame 1 to form a superhydrophobic coating. Utilizing the repellency of the superhydrophobic material to water, water droplets cannot slide and spread on its surface but remain in a spherical rolling state, thereby achieving the effect of self-cleaning by rolling. This can not only keep the inner wall of the cell frame clean but also prevent the electrolyte from corroding the inner wall of the cell frame. The superhydrophobic material with high temperature and strong alkali resistance in this embodiment is PTFE coating or other materials with the same function.

[0038] Embodiment Two

[0039] As Figure 7 shown, cascading and stacking two or more metal-air battery cells in Embodiment One can form a large-capacity metal-air battery stack system, and the electrolyte circulation channels on all battery cells are docked to form a stack electrolyte circulation system. First, the water inlet 111, the water outlet 112, and the breathing port 114 in this embodiment all penetrate the cell frame along the cascading and stacking direction of the cell frame. Additionally, fixed through holes 131 for stacking and connecting the battery cells are provided in the non-reaction cavity area of the cell frame 1, and the fixed through holes 131 also penetrate the cell frame along the stacking direction of the cell frame. The water inlet 111, the water outlet 112, the breathing port 114, and the fixed through holes 131 are all cylindrical holes, and the tops of the water inlet 111 and the water outlet 112 are respectively in phase-connection and communication with the reaction cavity 102 and the reflux cavity 116 inside their respective cell frames.

[0040] When all metal-air battery monomers are cascaded and stacked, a connecting rod passes through the coaxially aligned fixed through holes 131 on the monomer frame 1, and all monomer batteries are stacked and pressed tightly using pressing plates from both ends. The water inlets 111, water outlets 112, and breathing ports 114 on adjacent monomer frames are coaxially docked and connected one by one respectively. The adjacent docking channels are sealed and assembled with sealing rings. The water inlet at one end on the outer side of the stack is connected to an electrolyte delivery device, generally a delivery pump; the water inlet at the other end on the other side of the stack serves as a slag discharge port and is connected to a residue recovery device through a valve. When there is residue at the bottom of the battery, it can be flushed through the water inlet. Residue recovery can be a common electrolyte recovery device or a separate recovery tank. The outermost water outlet is connected to an electrolyte recovery device through a pipeline, generally a recovery tank, and the outermost breathing port is connected to the atmosphere or a gas recovery device through a pipeline.

[0041] The circulation channel of the electrolyte in the stack can be regarded as long pipeline transportation. When the electrolyte flows inside the long pipeline, a "fish-belly distribution" effect will be generated in the direction perpendicular to the conveying direction, resulting in inconsistent rising amplitudes of the liquid levels inside the reaction cavities of each monomer battery in the stack. Specifically, it is manifested as follows: (1) When supplying liquid unidirectionally, the height increases from one end of the water inlet to the other end; (2) When supplying liquid bidirectionally, the two ends of the water inlets are low and the middle part is high. Even in some battery monomer reaction cavities, the liquid level height of the electrolyte cannot reach the overflow height and thus cannot form an electrolyte circulation. To avoid this phenomenon, referring back to Figure 3 , in this embodiment, a spoiler 113 is provided inside the water inlet 111 of the monomer frame. The spoiler 113 forms a disturbance to the electrolyte flowing in the docking channel of the water inlet, ultimately making the rising amplitudes and flow velocities of the electrolyte liquid levels in the reaction cavities inside the cascaded and stacked monomer batteries tend to be consistent.

[0042] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and the description of the present invention.

Claims

1. Electrolyte circulation system of a metal-air battery stack, characterized in that: The metal-air battery stack includes at least two metal-air battery monomers mounted in cascade and stacked. An electrolyte circulation channel is provided on the monomer frame of the metal-air battery monomer. The electrolyte circulation channel includes a reaction cavity provided within the monomer frame and a water inlet and a water outlet provided on the monomer frame and internally communicating with the reaction cavity; The top of the reaction cavity communicates with a reflux cavity through an overflow port. The water inlet is provided at the bottom of the reaction cavity, and the water outlet is provided at the bottom of the reflux cavity; the bottom of the reaction cavity is a funnel-shaped slope, and the lowest position of the slope is docked to the water inlet; After the electrolyte enters the reaction cavity from the water inlet, it flows through the reflux cavity through the overflow port at the top and then flows out from the water outlet; The electrolyte circulation channel further includes a breathing port provided on the monomer frame. The setting position of the breathing port is higher than that of the overflow port. The breathing port is located above the reflux cavity and is connected to the inside of the reaction cavity; A horizontally arranged overflow platform with a tongue structure is provided between the overflow port and the reflux cavity; A flow disturbing plate for disturbing the liquid flow is provided inside the water inlet; The electrolyte circulation system includes at least two of the electrolyte circulation channels. The water inlets and water outlets of the electrolyte circulation channels are both provided on the monomer frame in a penetrating manner along the stacking direction of the monomer frames. The water inlets between adjacent monomer frames are coaxially docked and communicated, and the water outlets between adjacent monomer frames are coaxially docked and communicated. The water inlet at one end outside the battery stack is connected to an electrolyte delivery device, the water inlet at the other end outside the battery stack serves as a slag discharge port and is connected through a valve and a residue recovery device, and the water outlet at the outermost side of the battery stack is connected to an electrolyte recovery device.

2. The electrolyte circulation system of the metal-air battery stack according to claim 1, wherein: The reflux cavity is provided on both sides of the reaction cavity, and the two groups of water outlets are respectively located at the bottom of the reflux cavity.

3. The electrolyte circulation system of the metal-air battery stack according to claim 1, characterized in that: The water inlet is provided in the middle of the bottom of the reaction cavity.

4. The electrolyte circulation system of the metal-air battery stack according to claim 1, characterized in that: A superhydrophobic coating resistant to high temperature and strong alkali is provided on the contact surface inside the monomer frame that contacts the electrolyte.

5. The electrolyte circulation system of the metal-air battery stack according to claim 1, characterized in that: The top of the water inlet is connected to the reaction cavity, and the top of the water outlet is connected to the reflux cavity.

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