Aluminum sea water fuel cell

Abstract

The present application relates to a kind of aluminum seawater fuel cells.It is specifically a kind of high volume ratio energy soft package aluminum seawater fuel cell that can be floated in water and long time stable discharge, single cell is adopted porous composite membrane of two different materials, material A is close to aluminum anode side, material B is close to cathode side;The diaphragm material A is one of polyethylene (PE), polypropylene (PP), nylon (PA), glass fiber (GF), polyurethane (PU), polysulfone (PS), sulfonated polyether ether ketone (SPEEK);The diaphragm material B is one of polyethylene (PE), polypropylene (PP), nylon (PA), polyethylene terephthalate (PET), glass fiber (GF), polyurethane (PU), polysulfone (PS), polyvinylidene fluoride (PVDF), sulfonated polyether ether ketone (SPEEK), polytetrafluoroethylene (PTFE).

Description

Technical Field

[0001] The present invention relates to an aluminum-seawater fuel cell, specifically a high-volume-energy soft-pack aluminum-seawater fuel cell with buoyancy controllable in water and long-term stable discharge. Background Art

[0002] The new aluminum-seawater fuel cell is an electrochemical reaction device that uses aluminum and its alloys as the anode fuel, and alkaline seawater as the oxidant and electrolyte solution. Due to its high specific energy, safety, and reliability, the new aluminum-seawater fuel cell has broad application prospects in powering marine equipment, such as deep-sea landers. Deep-sea equipment power sources require high specific energy levels for batteries capable of operating at full ocean depths. Currently, all-solid-state lithium batteries and silver-zinc batteries have drawbacks such as low specific energy levels and high costs for full ocean depth application. Furthermore, due to the limited buoyancy adjustment range of deep-sea landers and other marine equipment, strict requirements are placed on the buoyancy range of the equipment's power supply. During the reaction of an alkaline aluminum-seawater fuel cell, hydroxide and hydrogen are generated. Initially, hydrogen accumulates between the porous cathode and the anode and cathode in the cell, causing the battery weight to drop rapidly. Subsequently, the product, aluminum hydroxide, dissolves in the electrolyte and gradually precipitates as the alkali is consumed, accumulating in the cell. At this point, the battery weight gradually increases. Due to the uneven distribution of product precipitation, the volume expansion of individual cells is irregular, and the amount of gas retained in a single cell is random. This easily disrupts the balance between the buoyancy generated by the gas in each cell and the weight of the cell, making it difficult to maintain the real-time balance required during actual use of the lander. Adding buoyancy adjustment devices, such as springs or other force-applying structures, would increase the volume and weight of the battery and reduce its specific energy. Summary of the Invention

[0003] In response to the above-mentioned problems of batteries, the present invention invents a new type of aluminum-seawater fuel cell, which achieves a high volume-to-energy ratio of the battery while having the function of regulating buoyancy in water to meet the long-term use requirements of equipment such as landers at full sea depth.

[0004] An aluminum-seawater fuel cell comprises a battery pack consisting of N single cells arranged in parallel from left to right, wherein N is an integer greater than or equal to 2;

[0005] The single cell comprises a single cell housing, a cathode and an anode arranged alternately and in parallel in the housing, a separator provided between the cathode and the anode, at least one cathode and one anode, the number of cathode and anode being the same or differing by one, and an electrolyte provided in the housing between the cathode and the anode or below the cathode and the anode; and characterized in that:

[0006] The diaphragm is a porous composite membrane made of two different materials, material A is on the side close to the aluminum anode, and material B is on the side close to the cathode;

[0007] The diaphragm material A is one of polyethylene (PE), polypropylene (PP), nylon (PA), glass fiber (GF), polyurethane (PU), polysulfone (PS), sulfonated polyetheretherketone (SPEEK), etc.

[0008] The diaphragm material B2 is one of polyethylene (PE), polypropylene (PP), nylon (PA), polyethylene terephthalate (PET), glass fiber (GF), polyurethane (PU), polysulfone (PS), polyvinylidene fluoride (PVDF), sulfonated polyetheretherketone (SPEEK), polytetrafluoroethylene (PTFE), etc.;

[0009] The diaphragm material A and the diaphragm material B are compounded by one or more methods selected from the group consisting of coating compounding, lamination compounding, adhesive compounding, film layer fusion, stretch film compounding, and chemical compounding;

[0010] The pore size of the diaphragm is 0.1 nm to 500 μm;

[0011] The separator reacts with the battery, so that the reaction products are evenly precipitated between the two membranes;

[0012] The separator expands in volume as the battery reaction proceeds and products are precipitated;

[0013] The expansion of the diaphragm volume drives the expansion of the single cell soft shell, and the volume of the single cell increases;

[0014] The electrolyte is one or a mixture of two or more of NaOH, KOH, etc.

[0015] The electrolyte additive is sodium stannate;

[0016] The single cell housing is a pure soft shell or a hard frame sealed with a soft film. The soft material includes PET / PE, BOPP / PP, BOPP / PE, BOPP / PP, PET / PP, PA / PE, PET / PA / PE, PET / PA / PE, PET / PA / PP and other composite plastic films, ABS sheets, rubber, etc. The hard frame includes PP, PE, ABS and other materials. PET is polyethylene terephthalate, PP is polypropylene, PE is polyethylene, and PA is nylon.

[0017] The single battery circuits in the battery pack are connected in series, in parallel, or in a mixture of series and parallel.

[0018] The coating composite is to coat a liquid or molten material on a substrate through a coating technique, and then cover it with another layer of material to form a composite film.

[0019] The lamination process is to place two or more layers of materials together and bond them together through heating and pressure to form a composite film.

[0020] The adhesive lamination method is to use an adhesive to bond two or more materials together to form a composite film.

[0021] The film layer fusion is to stack thin films of two or more materials together and bond them together through thermal fusion to form a composite film.

[0022] The stretch film composite comprises: stretching two or more materials at a certain stretching ratio, and then bringing them into contact and composited together.

[0023] The chemical composite utilizes chemical reactions to combine two or more materials together at the molecular level to form a composite film.

[0024] Compared with the existing technology, the metal seawater fuel cell of the present invention has the following advantages:

[0025] (1) By setting a composite diaphragm structure between the anode and cathode of a single cell, the products of the aluminum-seawater fuel cell are directionally precipitated along with the reaction, the rate of increase of the battery volume is orderly controlled, and the buoyancy change of the aluminum-seawater fuel cell is adjusted, so that the aluminum-seawater fuel cell can meet the use requirements of mobile devices in the full sea depth range;

[0026] (2) The battery uses a soft shell to wrap the cathode, anode and separator arranged alternately in parallel. It has a simple structure, no additional buoyancy adjustment device, a small size, high specific energy, and is easy to store and carry; BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Example metal seawater fuel cell buoyancy change diagram;

[0028] Figure 2 Buoyancy variation diagram of comparative metal seawater fuel cell;

[0029] Figure 3 Example: Diaphragm image before testing, diaphragm thickness 0.1 mm;

[0030] Figure 4 Image of the diaphragm after testing in Example, the thickness of the diaphragm is about 10 mm;

[0031] Figure 5 ,After the test in the embodiment, obvious stratification can be seen after the diaphragm is cleaned. DETAILED DESCRIPTION

[0032] Example: Aluminum alloy 7075 is used as the anode, with dimensions (length × width × thickness) of 12 cm × 10 cm × 4 mm, and nickel foam is used as the cathode, with dimensions (length × width × thickness) of 12 cm × 10 cm × 2 mm, and the reaction area is 120 cm2 The diaphragm is a commercial laminated composite polypropylene / polyethylene composite film, each layer is about 50μm thick, the total thickness is 100μm, the size (length × width × thickness) is 13cm × 10cm × 0.17m, the pore size is 100μm, and it is placed between the cathode and the anode. There are 2 anodes and 3 cathodes in a single cell. The cathode-diaphragm-anode-diaphragm-cathode... are arranged alternately in sequence. The electrolyte is a 20% mass concentration of sodium hydroxide and seawater mixed solution, and 500ml is added to each cell. The outer shell is an ABS plastic frame bonded with an ABS plastic film, the film thickness is 0.15mm, the shell size (length × width × height) is 15cm × 1.5cm × 25cm, and an exhaust hole is set on the top of the single cell. The battery pack is 3 single cells connected in series, and is hoisted in the water as a whole through the frame. A gravity sensor is connected in series between the battery and the bracket, with a pressure of 1mA / cm 2 During constant current discharge, record the changes in gravity in the water of the battery pack and repeat the test twice. Figure 1 shown.

[0033] Compared with the comparative example, under the same discharge current density, the weight change of the single battery in the embodiment during discharge is significantly smaller than that in the comparative example. Only in the initial stage, the weight decreases significantly with the accumulation of hydrogen. Then, as the reaction proceeds, the weight remains relatively stable. Compared with the comparative example, the buoyancy is controllable. After the reaction, the internal diaphragm of the battery is Figure 4 As shown, the diaphragm thickness is determined by Figure 3 The initial state of 0.1mm is changed to about 10mm. After cleaning, the diaphragm is as follows Figure 5 As shown in the figure, the product can be completely removed, and the membrane shows obvious stratification, which is caused by the precipitation of the product between the layers.

[0034] Comparative Example: Aluminum alloy 7075 is used as the anode, with dimensions (length × width × thickness) of 12 cm × 10 cm × 4 mm, and nickel foam is used as the cathode, with dimensions (length × width × thickness) of 12 cm × 10 cm × 2 mm, and the reaction area is 120 cm 2 The separator is a single-layer PP film (polypropylene film) with dimensions (length × width × thickness) of 13 cm × 10 cm × 0.17 m and a pore size of 100 μm. It is placed between the cathode and anode. A single cell contains two anodes and three cathodes. The cathode-separator-anode-separator-cathode... arrangement is used in an alternating sequence. The electrolyte concentration and addition amount are the same as in the example. The battery pack consists of three cells connected in series, which are charged at 1 mA / cm 2 During constant current discharge, record the changes in gravity in the water of the battery pack, such as Figure 2 Compared with the embodiment, under the same discharge current density, the buoyancy change of the battery pack is close to 1 kg, and the weight change trends of the two measurements are different, confirming that the product is non-directionally precipitated and the gravity change is uncontrollable.

Claims

1. An aluminum-seawater fuel cell, comprising a battery pack consisting of N single cells arranged in parallel from left to right, where N is an integer greater than or equal to 2; The single cell comprises a single cell housing, a cathode and an anode arranged alternately and in parallel in the housing, a separator provided between the cathode and the anode, at least one cathode and one anode, the number of cathode and anode being the same or differing by one, and an electrolyte provided in the housing between the cathode and the anode or below the cathode and the anode; and is characterized in that: The diaphragm is a porous composite membrane made of two different materials, material A is on the side close to the aluminum anode, and material B is on the side close to the cathode; The diaphragm material A is one of polyethylene (PE), polypropylene (PP), nylon (PA), glass fiber (GF), polyurethane (PU), polysulfone (PS), and sulfonated polyetheretherketone (SPEEK); The diaphragm material B is one of polyethylene (PE), polypropylene (PP), nylon (PA), polyethylene terephthalate (PET), glass fiber (GF), polyurethane (PU), polysulfone (PS), polyvinylidene fluoride (PVDF), sulfonated polyetheretherketone (SPEEK), and polytetrafluoroethylene (PTFE); the single cell shell is a soft shell.

2. The battery according to claim 1, characterized in that: The pore size of the diaphragm is 0.1 nm to 500 μm.

3. The battery according to claim 1 or 2, characterized in that: The diaphragm material A and the diaphragm material B are compounded by one or more methods including coating compounding, lamination compounding, adhesive compounding, film layer fusion, stretch film compounding, chemical compounding, etc.

4. The battery according to claim 1, characterized in that: The electrolyte is one of NaOH and KOH or a mixture of two or more thereof, and its mass concentration in seawater is 10% to 90%.

5. The battery according to claim 1, characterized in that: The electrolyte additive is sodium stannate, and its mass concentration in seawater is 2% to 20%.

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