Aluminum seawater fuel cell

Abstract

The invention relates to an aluminum seawater fuel cell. In particular to a high volumetric specific energy soft package aluminum seawater fuel cell capable of regulating buoyancy in water and stably discharging for a long time, a diaphragm adopted by a single cell is a porous composite membrane made of two different materials, the material A is close to one side of an aluminum anode, and the material B is close to one side of a cathode; the diaphragm material A is one of polyethylene (PE), polypropylene (PP), nylon (PA), glass fiber (GF), polyurethane (PU), polysulfone (PS) and sulfonated polyether ether ketone (SPEEK); and 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) and polytetrafluoroethylene (PTFE).

Description

Technical Field

[0001] The present invention relates to an aluminum seawater fuel cell, in particular to a high volume specific 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 anode fuel, and alkaline seawater as oxidant and electrolyte solution. The new aluminum-seawater fuel cell has broad application prospects in the field of marine equipment power supplies such as deep-sea lander power supplies due to its high specific energy, safety and reliability. Deep-sea equipment power supplies have high requirements for the specific energy of batteries used in the full sea depth range. Currently, all-solid-state lithium batteries and silver-zinc batteries have disadvantages such as low specific energy and high cost for full sea depth applications. At the same time, marine equipment such as deep-sea landers have strict requirements on the buoyancy variation range of equipment power supplies due to the limitations of their buoyancy adjustment range. During the reaction of alkaline aluminum seawater fuel cells, hydroxide and hydrogen are generated. Initially, hydrogen accumulates in the porous cathode and between the anode and cathode in the battery, 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 battery. At this time, the battery weight gradually increases. Due to the uneven distribution of product precipitation, the volume expansion of a single cell is irregular, and the amount of gas retained in a single cell is random, the balance between the buoyancy generated by the gas in a single cell and the gravity of a single cell is easily destroyed, making it difficult to meet the real-time balance during the actual use of the lander. If a buoyancy adjustment device, such as a spring or other force-applying structure, is added, the volume and weight of the battery will increase, and the specific energy will decrease. Summary of the invention

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

[0004] An aluminum-seawater fuel cell, comprising a battery pack composed 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 shell, a cathode and an anode arranged alternately and in parallel in the shell, a separator arranged between the cathode and the anode, at least one cathode and one anode, the number of cathode and anode sheets being the same or differing by one, and an electrolyte being arranged in the shell at or below the anode and the cathode; the characteristics are as follows:

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

[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, chemical compounding, etc.;

[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 product is evenly precipitated between the two layers of the membrane;

[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 shell 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 matched therewith. 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 series-parallel hybrid.

[0018] The coating composite is to coat the liquid or molten material on the substrate by coating technology, 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 by heating and pressure to form a composite film.

[0020] The adhesive bonding 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 by thermal fusion to form a composite film.

[0022] The stretch film composite is as follows: two or more materials are stretched at a certain stretching ratio, and then brought into contact and composited together.

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

[0024] Compared with the prior art, 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 oriented and 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 diaphragm which are arranged alternately and in parallel. It has a simple structure, no additional buoyancy adjustment device, a small volume, high specific energy, and is easy to store and carry; BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Embodiment Metal seawater fuel cell buoyancy change diagram;

[0028] Figure 2 Comparative metal seawater fuel cell buoyancy change diagram;

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

[0030] Figure 4 Image of the diaphragm after the test in the embodiment, 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 12cm × 10cm × 4mm, and nickel foam is used as the cathode, with dimensions (length × width × thickness) of 12cm × 10cm × 2mm, and the reaction area is 120cm2 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 sodium hydroxide 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 1mA / cm 2 During the constant current discharge, record the gravity change of the battery pack in water 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 given by Figure 3 The initial state of 0.1mm is changed to about 10mm. After cleaning, the diaphragm is Figure 5 As shown, the product can be completely removed and the membrane shows obvious stratification, which is caused by the product precipitating between the layers and causing the separation of the two layers.

[0034] Comparative example: Aluminum alloy 7075 is used as the anode, with dimensions (length × width × thickness) of 12cm × 10cm × 4mm, and nickel foam is used as the cathode, with dimensions (length × width × thickness) of 12cm × 10cm × 2mm, and the reaction area is 120cm 2 The separator is a single-layer PP film (polypropylene film), with dimensions (length × width × thickness) of 13cm × 10cm × 0.17m, and a pore size of 100μm. It is placed between the cathode and the anode. There are 2 anodes and 3 cathodes in a single cell. The cathode-separator-anode-separator-cathode...are alternately arranged in sequence. The electrolyte concentration and addition amount are the same as in the embodiment. The battery pack is 3 single cells connected in series, which are charged at 1mA / 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 1kg, and the weight change trends of the two measurements are different, which confirms that the product is non-directionally precipitated and the gravity change is uncontrollable.

Claims

1. An aluminum-seawater fuel cell, comprising a battery pack composed of N single cells arranged in parallel from left to right, wherein N is an integer greater than or equal to 2; The single cell comprises a single cell shell, a cathode and an anode arranged alternately and in parallel in the shell, a separator arranged between the cathode and the anode, at least one cathode and one anode, the number of cathode and anode sheets being the same or differing by one, and an electrolyte being arranged in the shell at or below the anode and the cathode; the characteristics are as follows: The diaphragm is a porous composite membrane made of two different materials, material A is close to the aluminum anode side, and material B is close to the cathode side; 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 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), and polytetrafluoroethylene (PTFE).

2. The battery according to claim 1, characterized in that: The pore size of the diaphragm is 0.1 nm to 500 μm, preferably 1 to 5 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 selected from the group consisting of coating compounding, lamination compounding, adhesive compounding, film layer fusion, stretch film compounding, chemical compounding, and the like.

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%, preferably 20%.

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%, preferably 5%.

6. The battery according to claim 1, characterized in that: The single battery housing is a soft housing.

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