A water-activated sealed alkaline aluminum-air battery

Abstract

The application relates to a water-activated sealed alkaline aluminum-air battery, which comprises a battery shell, an aluminum electrode and an air electrode, the aluminum electrode is arranged in the battery shell, the air electrode is arranged at a through hole of a side wall surface of the battery shell, the four peripheral edges of the air electrode are in closed connection with the four peripheral wall surfaces of the battery shell at the opening end of the through hole or the inner wall surfaces of the through hole, a water injection port is arranged at the top of the battery shell, a sealing cover capable of opening and closing the water injection port is arranged on the water injection port, a through hole is arranged at the top of the battery shell, a waterproof air-permeable film is arranged at the through hole, the waterproof air-permeable film covers the through hole, the four peripheral edges of the waterproof air-permeable film are in closed connection with the four peripheral wall surfaces of the battery shell at the opening end of the through hole or the inner wall surfaces of the through hole, and a solid electrolyte is filled in the battery shell. The aluminum-air battery has the advantages of high voltage and high capacity of the alkaline aluminum-air battery, water-activated operation, no contact with alkali, safety and convenience.

Description

Technical Field

[0001] This invention belongs to the field of aluminum-air battery technology, specifically relating to a sealed alkaline aluminum-air battery that can be activated by adding water, solving the problems of inconvenience and poor safety of alkaline aluminum-air batteries, while ensuring high voltage and high capacity. Background Technology

[0002] Aluminum-air batteries are chemical power sources that use metallic aluminum and oxygen from the air as the reactive materials. The negative electrode is typically an aluminum alloy plate, the positive electrode is an air electrode, and the electrolyte is an alkaline or neutral aqueous solution. Aluminum has an electrochemical equivalent of 2.98 Ah / g, second only to lithium, and the oxygen used as the positive electrode comes from the air, thus aluminum / air batteries exhibit high specific energy. Furthermore, metallic aluminum is abundant, safe to use, and its reaction products are non-toxic and recyclable, making it an ideal electrode material.

[0003] Aluminum-air batteries using an alkaline electrolyte system exhibit higher discharge voltage and capacity compared to neutral electrolyte systems. However, alkaline solutions are highly corrosive, making it extremely inconvenient to add alkaline electrolyte to aluminum-air batteries before use. Pre-embedding solid alkali within the aluminum-air battery and activating it with water before use is a feasible solution, but this introduces the problem that the solid alkali generates a large amount of heat during dissolution, causing rapid hydrogen evolution corrosion of the aluminum electrodes in the hot electrolyte, ultimately affecting battery safety. Chinese patent (CN107017411B) mentions a portable, high-efficiency aluminum-oxygen power battery using potassium hydroxide and cyclodextrin colloidal electrolytes that can operate with water injection.

[0004] This invention proposes a sealed alkaline aluminum-air battery that is activated by adding water. By using a low-heat electrolyte pre-embedded technology, the aluminum-air battery only needs to be filled with water before it can be put into operation. The aluminum-air battery adopts a fully sealed structure with a waterproof and breathable membrane, so the operator does not come into contact with the alkaline electrolyte during use. It has the characteristics of high safety and convenient use. Summary of the Invention

[0005] A sealed alkaline aluminum-air battery activated by water includes a battery casing, aluminum electrodes, air electrodes, a low-heat-generating solid electrolyte, a waterproof and breathable membrane, and a water inlet. The low-heat-generating solid electrolyte is a mixture of solid alkali and other salts, and the waterproof and breathable membrane allows for battery venting while ensuring liquid sealing.

[0006] The low-heat-generating solid electrolyte comprises four components: component 1 is potassium hydroxide, sodium hydroxide, or a mixture of both; component 2 is potassium stannate, sodium stannate, or a mixture of both; component 3 is one or more of ammonium nitrate, ammonium oxalate, ammonium sulfate, potassium nitrate, potassium oxalate, potassium bromide, sodium nitrate, sodium oxalate, sodium bicarbonate, calcium nitrate, and calcium chloride; and component 4 is deionized water. The mixing method for the low-heat-generating solid electrolyte involves weighing the four components according to the specified proportions, melting and mixing them at high temperature, cooling and solidifying them, and then mechanically pulverizing them.

[0007] The waterproof and breathable membrane is a multilayer composite membrane composed of one or more of the following: polytetrafluoroethylene porous membrane and polyethylene porous membrane, polypropylene porous membrane, polyvinylidene fluoride porous membrane, and polyethylene terephthalate porous membrane. The pore size distribution ranges from 0.01 μm to 10 μm.

[0008] The aluminum electrode contains at least 95% metallic aluminum.

[0009] The air electrode comprises a catalyst layer, a current collector, and a gas diffusion layer.

[0010] The battery casing is one or more blends of ABS, polycarbonate, polypropylene, polyethylene, and nylon. The battery casing, air cathode, and waterproof and breathable membrane are bonded together with epoxy resin or integrally injection molded to form a sealed battery cavity.

[0011] Description of the implementation effect: Compared with the prior art, the aluminum-air battery of the present invention has the advantages of high voltage and high capacity of alkaline aluminum-air battery, while realizing water activation, so that the operator does not come into contact with alkali, making it safe and convenient. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of the sealed alkaline aluminum-air battery activated by water according to the present invention.

[0013] Figure 2 This is a top view schematic diagram of the sealed alkaline aluminum-air battery activated by adding water according to the present invention.

[0014] In the diagram, 1 is the battery casing, 2 is the battery cover, 3 is the air electrode, 4 is the aluminum electrode, 5 is the solid electrolyte, and 6 is the waterproof and breathable membrane. Detailed Implementation

[0015] The following embodiments further illustrate the present invention in detail, but are not intended to limit the invention.

[0016] like Figure 1 and 2As shown, a water-activated sealed alkaline aluminum-air battery includes a 150mL rectangular battery casing with an internal cavity, aluminum electrodes, and air electrodes. The aluminum electrodes are placed inside the battery casing, and the air electrodes are placed at a through-hole A on the side wall of the battery casing. The four edges of the air electrodes are sealed to the inner wall of the through-hole A. A water inlet is provided at the top of the battery casing, and a sealing cap that can be opened and closed is provided on the water inlet. A through-hole B is provided at the top of the battery casing, and a waterproof and breathable membrane is provided at through-hole B, covering the through-hole. The four edges of the waterproof and breathable membrane are sealed to the four walls of the battery casing at the opening end of the through-hole. A solid electrolyte is filled inside the battery casing. Two air electrodes are respectively arranged on the left and right sides of the battery casing, and the aluminum electrode is located between the two air electrodes. The aluminum electrode and the two air electrodes are arranged alternately and parallel to each other. The sealing cap is screwed onto the water inlet.

[0017] Example 1

[0018] The aluminum electrode is a sheet of high-purity aluminum with a length * width of 9cm * 7cm and a thickness of 1mm. The air electrode is a sheet with a length * width of 10cm * 8cm, formed by laminating a catalyst layer, a copper mesh, and a gas diffusion layer. The catalyst layer is prepared by spraying and drying a mixture of manganese dioxide, carbon powder, and 40% polytetrafluoroethylene emulsion in a mass ratio of 1:5:3. The gas diffusion layer is formed by hot pressing a mixture of carbon powder and polytetrafluoroethylene in a mass ratio of 2:1 at 300 degrees Celsius. The solid electrolyte consists of 25g potassium hydroxide, 1.2g sodium stannate, 12g ammonium oxalate, and 5g deionized water (the solid electrolyte is prepared by mixing the four components, melting and mixing them at 150°C, cooling to room temperature to solidify, and then mechanically pulverizing them into powder). The waterproof and breathable membrane is a composite membrane of polytetrafluoroethylene porous membrane and polyvinylidene fluoride porous membrane (manufacturer: Shanghai Minglie New Materials Co., Ltd., model: X1010), with an average pore size of 0.1μm. The battery casing is made of ABS plastic and is integrally injection molded to form a sealed battery cavity with the air electrode and waterproof and breathable membrane. Before use, add 90mL of water to the aluminum-air battery, tighten the sealing cap on the water inlet, and shake the battery. The battery surface temperature was monitored to be 45℃, the battery casing showed no expansion, and the waterproof and breathable membrane showed no leakage. The above aluminum-air battery was then tested at 10mW / cm². 2 Discharges at power density until the battery low-voltage protection reaches 0.9V, with a discharge capacity of 45Ah.

[0019] Example 2

[0020] The aluminum electrode is a sheet of high-purity aluminum with a length * width of 9cm * 7cm and a thickness of 1mm. The air electrode is a sheet with a length * width of 10cm * 8cm, formed by laminating a catalyst layer, a copper mesh, and a gas diffusion layer. The catalyst layer is prepared by spraying and drying a mixture of manganese dioxide, carbon powder, and 40% polytetrafluoroethylene emulsion in a mass ratio of 1:5:3. The gas diffusion layer is formed by hot pressing a mixture of carbon powder and polytetrafluoroethylene in a mass ratio of 2:1 at 300 degrees Celsius. The solid electrolyte consists of 25g potassium hydroxide, 1.2g sodium stannate, 15g potassium nitrate, and 5g deionized water (the solid electrolyte is prepared by mixing the four components, melting and mixing them at 150°C, cooling to room temperature to solidify, and then mechanically pulverizing them into powder). The waterproof and breathable membrane is a composite membrane of polytetrafluoroethylene porous membrane and polyvinylidene fluoride porous membrane (manufacturer: Shanghai Minglie New Materials Co., Ltd., model: X2020), with an average pore size of 0.2μm. The battery casing is made of ABS plastic and is integrally injection molded to form a sealed battery cavity with the air electrode and waterproof breathable membrane. Before use, add 90mL of water to the aluminum-air battery, tighten the sealing cap on the water inlet, and shake the battery. The battery surface temperature was monitored to be 40℃, the battery casing showed no expansion, and the waterproof breathable membrane showed no leakage. The above aluminum-air battery was then tested at 10mW / cm². 2 Discharge at power density until the battery low-voltage protection reaches 0.9V, with a discharge capacity of 48Ah.

[0021] Example 3

[0022] The aluminum electrode is a sheet of high-purity aluminum with a length * width of 9cm * 7cm and a thickness of 1mm. The air electrode is a sheet with a length * width of 10cm * 8cm, formed by laminating a catalyst layer, a copper mesh, and a gas diffusion layer. The catalyst layer is prepared by spraying and drying a mixture of manganese dioxide, carbon powder, and 40% polytetrafluoroethylene emulsion in a mass ratio of 1:5:3. The gas diffusion layer is formed by hot pressing a mixture of carbon powder and polytetrafluoroethylene in a mass ratio of 2:1 at 300 degrees Celsius. The solid electrolyte consists of 25g sodium hydroxide, 1.0g sodium stannate, 9g sodium oxalate, and 8g deionized water (the solid electrolyte is prepared by mixing the four components, melting and mixing them at 150°C, cooling to room temperature to solidify, and then mechanically pulverizing them into powder). The waterproof and breathable membrane is a composite membrane of polytetrafluoroethylene porous membrane and polyvinylidene fluoride porous membrane, with an average pore size of 0.2μm (manufacturer: Shanghai Minglie New Materials Co., Ltd., model: X2020). The battery casing is made of ABS plastic and is integrally injection molded to form a sealed battery cavity with the air electrode and waterproof breathable membrane. Before use, add 90mL of water to the aluminum-air battery, tighten the sealing cap on the water inlet, and shake the battery. The battery surface temperature was monitored to be 44℃, the battery casing showed no expansion, and the waterproof breathable membrane showed no leakage. The above aluminum-air battery was tested at 10mW / cm². 2Discharge at power density until the battery low-voltage protection reaches 0.9V, with a discharge capacity of 43Ah.

[0023] Comparative Example 1

[0024] The aluminum electrode is a sheet of high-purity aluminum with a length * width of 9cm * 7cm and a thickness of 1mm. The air electrode is a sheet with a length * width of 10cm * 8cm, formed by laminating a catalyst layer, a copper mesh, and a gas diffusion layer. The catalyst layer is prepared by spraying and drying a mixture of manganese dioxide, carbon powder, and 40% polytetrafluoroethylene emulsion in a mass ratio of 1:5:3. The gas diffusion layer is formed by hot pressing a mixture of carbon powder and polytetrafluoroethylene in a mass ratio of 2:1 at 300 degrees Celsius. The solid electrolyte consists of 25g of potassium hydroxide and 1.2g of sodium stannate (the solid electrolyte is prepared by mechanically grinding and mixing the two components). The waterproof and breathable membrane is a composite membrane of polytetrafluoroethylene porous membrane and polyvinylidene fluoride porous membrane (manufacturer: Shanghai Minglie New Materials Co., Ltd., model: X1010), with an average pore size of 0.1μm. The battery casing is made of ABS plastic and is integrally injection molded to form a sealed battery cavity with the air electrode and waterproof breathable membrane. Before use, add 90mL of water to the aluminum-air battery, tighten the sealing cap on the water inlet, and shake the battery. The battery surface temperature is monitored to be 85℃, the battery casing expands, and electrolyte seeps out through the waterproof breathable membrane. The above aluminum-air battery is then tested at 10mW / cm². 2 Discharge at power density until the battery low-voltage protection reaches 0.9V, with a discharge capacity of 29Ah.

[0025] Comparative Example 2

[0026] The aluminum electrode is a sheet of high-purity aluminum with a length * width of 9cm * 7cm and a thickness of 1mm. The air electrode is a sheet with a length * width of 10cm * 8cm, formed by laminating a catalyst layer, a copper mesh, and a gas diffusion layer. The catalyst layer is prepared by spraying and drying a mixture of manganese dioxide, carbon powder, and 40% polytetrafluoroethylene emulsion in a mass ratio of 1:5:3. The gas diffusion layer is formed by hot pressing a mixture of carbon powder and polytetrafluoroethylene in a mass ratio of 2:1 at 300 degrees Celsius. The solid electrolyte consists of 25g of sodium hydroxide and 1.0g of sodium stannate (the solid electrolyte is prepared by mechanically grinding and mixing the two components). The waterproof and breathable membrane is a composite membrane of polytetrafluoroethylene porous membrane and polyvinylidene fluoride porous membrane (manufacturer: Shanghai Minglie New Materials Co., Ltd., model: X2020), with an average pore size of 0.2μm. The battery casing is made of ABS plastic and is integrally injection molded to form a sealed battery cavity with the air electrode and waterproof breathable membrane. Before use, add 90mL of water to the aluminum-air battery, tighten the sealing cap on the water inlet, and shake the battery. Monitor the battery surface temperature; it should reach 92℃. The battery casing should expand, and electrolyte should leak from the waterproof breathable membrane. Discharge the aluminum-air battery at a power density of 10mW / cm² until the battery reaches low-voltage protection; the discharge capacity is 24Ah.

[0027] In the comparative example, after activating the aluminum-air battery with water, the battery temperature rose significantly, the battery casing expanded, and the battery leaked, resulting in a significant reduction in discharge capacity. In the embodiment using the improved solution, the battery surface temperature remained low after activation with water, the battery did not expand or leak, and the discharge capacity was effectively extended.

Claims

1. A water-activated sealed alkaline aluminum-air battery, comprising a battery casing, an aluminum electrode, and an air electrode, wherein the aluminum electrode is placed inside the battery casing, and the air electrode is placed at a through hole on the side wall of the battery casing, and the four edges of the air electrode are sealed to the four sides of the battery casing or the inner wall of the through hole at the opening end of the through hole, characterized in that: A water inlet is located at the top of the battery casing, and a sealing cap that can be opened and closed is provided on the water inlet. A through hole is located at the top of the battery casing, and a waterproof and breathable membrane is provided at the through hole, covering the through hole. The four edges of the waterproof and breathable membrane are sealed to the four walls of the battery casing at the opening end of the through hole or the inner wall of the through hole. A solid electrolyte is filled inside the battery casing. The solid electrolyte consists of four components: component 1 is potassium hydroxide, sodium hydroxide, or a mixture of the two; component 2 is potassium stannate, sodium stannate, or a mixture of the two; component 3 is one or more of ammonium nitrate, ammonium oxalate, ammonium sulfate, potassium nitrate, potassium oxalate, potassium bromide, sodium nitrate, sodium oxalate, sodium bicarbonate, calcium nitrate, and calcium chloride; and component 4 is deionized water. The solid electrolyte is prepared by mixing the four components in the required proportions, melting and mixing them at a high temperature of 110~200℃, cooling to solidify, and then mechanically crushing them.

2. The battery according to claim 1, characterized in that: The molar ratio of component 1 to component 2 is 1000:1 to 20:1, the molar ratio of component 1 to component 3 is 10:1 to 1:1, and the molar ratio of component 1 to component 4 is 10:1 to 1:

1.

3. The battery according to claim 2, characterized in that: The molar ratio of component 1 to component 2 is 500:1 to 100:1, the molar ratio of component 1 to component 3 is 8:1 to 2:1, and the molar ratio of component 1 to component 4 is 5:1 to 1:

1.

4. The battery according to claim 1, characterized in that: The waterproof and breathable membrane is a multilayer composite membrane composed of one or more of the following: polytetrafluoroethylene porous membrane, polyethylene porous membrane, polypropylene porous membrane, polyvinylidene fluoride porous membrane, and polyethylene terephthalate porous membrane; its pore size distribution ranges from 0.01 μm to 10 μm.

5. The battery according to claim 1, characterized in that: The aluminum electrode is one or more of aluminum or aluminum alloy, wherein the mass content of metallic aluminum is greater than or equal to 95%; The air electrode comprises a stacked catalytic layer, a current collector, and a gas diffusion layer.

6. The battery according to claim 1, characterized in that: The battery casing is one or more blends of ABS, polycarbonate, polypropylene, polyethylene, and nylon.

7. The battery according to claim 1 or 6, characterized in that: The battery casing and the air cathode, as well as the battery casing and the waterproof and breathable membrane, are bonded together with epoxy resin or fixed together during the integrated injection molding of the battery casing to form a sealed battery cavity.

8. The battery according to claim 1, characterized in that: The sealing cap is screwed onto the water inlet by threads.

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