JP2022164523A - Electrification system for vessel - Google Patents

Abstract

To provide an electrification system for a vessel capable of supplying a sufficient amount of power for electrification of the vessel while corresponding to safety navigation measures for the vessel.SOLUTION: An electrification system for a vessel includes a cell stack 1 and main tanks 2 and 3 connected to the self stack 1 through pipings 4, 5, 8 and 9, for storing electrolyte. The main tanks 2 and 3 are installed in a place for storing ballast water in the vessel and in the vicinity thereof, and the electrolyte is used for draft adjustment by reducing the amount of the ballast water for the amount of weight the stored electrolyte occupies in the main tanks 2 and 3 or by replacing whole quantity of the ballast water by the electrolyte when the main tanks 2 and 3 are installed in the position for storing the ballast water.SELECTED DRAWING: Figure 2

Description

The present invention relates to a ship electrification system.

Vessel electrification includes main propulsion (hereinafter referred to as M/E) and other onboard electrical power (hereinafter referred to as D/G) in a manner that does not emit carbon dioxide and air pollutants or toxic substances. , is defined as any means of obtaining power from, for example, renewable energy or other methods and using it via batteries or directly to a load. Other purposes of electrification of ships are to conserve marine ecosystems, prevent seawater pollution, promote renewable energy, and build basic infrastructure for ships in the near future as electronic engineering develops.

Therefore, at present, batteries in which the electrolytic solution or the electrolyte and the cell stack are integrated and cannot be separated (hereafter referred to as integrated type), such as lithium-based batteries, are installed onboard and used. However, with this means, the weight, volume, and cost of the batteries to be mounted are a great burden depending on the cruising distance of the ship. For example, in order to operate a container ship of 2,000 tons for 1,000 km, a 1 MW output battery consumes 1 MWh of electric power (hereinafter referred to as "ship example 1"). The onboard integrated battery is estimated to have a volume of 7 to 8 20-foot containers and a weight of 60 to 90 tons. The electrification of ships by batteries is limited to the method of using the small integrated battery for short-sea navigation and charging it frequently, or to supply power to the part corresponding to the D/G in the ship without electrifying the entire battery. ing.

Recently, researches using hydrogen-based fuel cells (hereinafter referred to as "fuel cells") have been conducted. A fuel cell is not an integrated type, but hydrogen is supplied to a cell stack from the outside and converted into electricity (hereinafter referred to as a "separate type"), but the energy efficiency at this time is as low as about 50%. In the case of ship example 1, the weight is about 5 tons, which is less than 1/10 of the above-mentioned integrated type, and there is no problem in mounting it onboard, but 980 K Little of hydrogen gas must be supplied to produce electricity. . There is a way to reduce the volume of liquefied hydrogen at -253°C, which cannot be loaded in such a large volume, to less than 1/500th of the original volume. The development of a system to feed hydrogen in the form of hydrogen to the cell stack is insufficient. Therefore, if methylcyclohexane (MCH) is used as a safer means of liquefaction, it will become a liquid at room temperature like gasoline. requires a hydrogen production system on board, which is currently not possible.

Another drawback of hydrogen-based fuel cells is that in the future, if the upper hull or deck is used to produce renewable energy such as solar and wind power and use it to electrify the ship, it will not be possible to charge it independently. Discharge is not possible. Alternatively, a process to obtain hydrogen gas from water electrolysis using renewable energy generated must be installed on board. Aside from the cost of the equipment, for example, when hydrogen is produced by electrolysis, 70% of the power generated on board is consumed, and the efficiency of the cell stack that converts hydrogen to electricity is 50%. %, so you can only use 15% of the total power you get.

As mentioned above, in consideration of the current state of ship electrification technology, drive trains M/E and D/G systems are included because the ship is in operation regardless of the tonnage according to the displacement classification of the ship, the purpose of ship operation, and the cruising distance. In order to achieve full electrification, technology is required to complete the electrification of ships using flow batteries.

A flow battery is a battery that converts electricity into chemical energy while changing the ionization state of the electrolyte by charging in the cell stack. Flow batteries, unlike integrated batteries, are separate batteries that store the electrolyte converted into chemical energy in a tank outside the cell stack and do not store the electrolyte inside the cell stack. .

In a general flow battery, the cell stack and the electrolyte tank are connected by a pipe, and the electrolyte flows into the cell stack using a pump and is discharged from the cell stack while circulating while charging and discharging. In order to safely operate the charge and discharge of the flow battery according to the specified performance, the cell stack and the electrolyte tank should be housed in the same box or container or in a commercial container. There is a need. Also, when a larger battery is installed outdoors, it is necessary to arrange the electrolyte tanks of the cell stack as close as possible. The reason for this is that factors relating to charging and discharging of the entire battery are controlled by a battery management system (hereinafter referred to as BMS). The BMS manages and controls the electrical data of the cell stack, and also monitors the temperature, flow rate, depth of charge, and remaining charge of the electrolyte while adjusting pump circulation conditions for the electrolyte. Therefore, in the case of a ship, unlike the conventional operation method, not only the battery system itself but also the ship on which the battery is installed are affected in various ways. These problems are described below.

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Battery performance is indicated by energy density, which expresses the amount of power that the battery can store per liter or per kilogram. For example, a lithium-ion battery, which is an example of an integrated battery, has a capacity of 250 Wh/L. On the other hand, the flow battery is 20-100Wh/L. many degrees. This energy density then provides a measure of the overall size and volume of the battery for the same power capacity. Therefore, the integrated battery will be lighter and lighter than the flow battery. The above vessel example 1. Then, the weight of the flow battery for outputting 1 MWh of electric energy for 1000 km navigation is about 100 tons to 400 tons, and it was difficult to carry on the ship.

On the other hand, in ship operation, trim adjustment and draft adjustment due to rocking are important for ship safety. These are interrelated factors, not separate ones, so they are adjusted by adjusting cargo and ballast water and so on. Batteries installed for electrification of ships are required to have a method corresponding to such measures for safe operation of ships.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a ship electrification system capable of supplying a sufficient amount of electric power for the electrification of a ship while complying with measures for safe operation of the ship.

means to solve the problem

(1) For flow batteries used on board,
a cell stack;
a main tank connected to the cell stack via a pipe and containing an electrolytic solution;
The electrification system for a ship, wherein the main tank is installed at or near a place for storing ballast water in the ship.

(2) When the main tank is installed in a place where ballast water is stored, the amount of ballast water is reduced by the weight of the electrolyte contained in the main tank, or the entire amount of ballast water is replaced by the electrolyte. The ship electrification system according to (1), characterized in that the electrolytic solution is used for draft adjustment by replacing with

(3) a buffer tank provided between the cell stack and the main tank and connected to the cell stack and the main tank via a pipe;
a pump that delivers electrolyte from the main tank to the buffer tank;
The ship electrification system according to (1) or (2), wherein the pump supplies the electrolyte from the main tank to the buffer tank and suppresses the flow rate of the electrolyte supplied to the cell stack.

(4) a first fluid control unit that controls the flow of electrolyte from the main tank to the cell stack;
The vessel electrification system according to any one of (1) to (3), further comprising: a second fluid control unit that controls a flow of electrolyte from the cell stack to the main tank.

(5) The vessel electrification system according to (3), wherein the buffer tank has an electrolyte storage capacity of 1/10 or less of the main tank.

(6) further comprising a C tank provided between the cell stack and the main tank and connected to the cell stack and the main tank via a pipe;
The second fluid control unit according to (4), wherein the electrolyte discharged from the cell stack is sent to the C tank, and the electrolyte stored in the C tank is sent to the main tank. Ship electrification system.

(7) When the draft and trim of the ship are adjusted using an electrolytic solution, the second fluid control unit controls a pump that moves the electrolytic solution for adjusting the draft and trim of the ship. The ship electrification system according to (4).

(8) The vessel electrification system according to any one of (1) to (7), wherein the charged electrolytic solution charged outside the vessel can be used.

(9) The ship electrification system according to any one of (1) to (8), wherein the electrolyte has a specific gravity of 0.8 or more and 1.8 or less.

Effect of the invention

According to the present invention, it is possible to provide a ship electrification system capable of supplying a sufficient amount of electric power for the electrification of a ship while complying with measures for safe operation of the ship.

FIG. 4 is a diagram showing the arrangement of electrolyte tanks of the present battery; Fig. 3 shows the new battery system when installing electrolyte tanks in the ballast water area; FIG. 4 is a diagram for explaining in detail a buffer tank in the case of a MW-class battery system; FIG. 2 is a diagram showing a battery system with an output of 1 MW; It is a figure which shows the battery system which set the C tank.

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. In the following description, the same or similar configurations are denoted by the same reference numerals, and their descriptions are omitted or simplified.

First, an outline of the flow battery will be explained.
The most typical flow battery is a vanadium redox flow battery (hereinafter referred to as VRFB). Many flow batteries in which zinc is used as a base material to create a redox reaction in pairs are under development or have been commercialized. It is For example, zinc-boron batteries (referred to as ZBB), zinc-bromine batteries (referred to as ZIFB), zinc-iron (Fe) batteries, and other mating materials such as chromium (Cr), nickel (Ni), cobalt (Co ), and when used to electrify a ship, the specific gravity of each electrolyte and its chemical composition are different. In this embodiment, VRFB will be described as an example.

A vanadium flow battery (hereinafter referred to as "the present battery") will be described below as a representative of the above-described various flow batteries, in which the specific gravity of the electrolyte is in the range of 1.0 or more and 1.8 or less.

In this embodiment, without specifying the distance between the cell stack of this battery and the electrolyte tank, and without specifying the material, shape, dimensions, etc. of the piping, the electrolyte tank is installed in the space where the ballast water tank is stored in the ship. It was decided to. A large amount of ballast water should be added, especially when the ship is empty, and draft measures should be taken.
Further, for example, in order to operate a 2,000-ton container ship for 1,000 km, a 1 MW output battery consumes 1 MWh of electric power (hereinafter referred to as "ship example 1").

In the case of Vessel Example 1, the amount of ballast water is determined to be 700 tons. The electrolyte required for a cruising distance of 1,000 km is 50 KL (weight: 65 tons). The electrolyte is not a toxic substance classified as a dilute sulfuric acid component, but can play the role of ballast water onboard. When the electrolyte is loaded, the ballast water is 700 - 65 = 635 tons.

FIG. 1 is a diagram showing the arrangement of electrolyte tanks of the present battery.
The cell stack 1 includes, as electrolyte tanks, which are examples of main tanks, a negative electrolyte tank 2 and a positive electrolyte tank 3, each of which is connected to the negative side of each cell. Electrolyte solution is supplied to the positive side by pumps 6 and 7 via pipes 4 and 5 (hereinafter referred to as "liquid feed pipes"). The electrolyte passes through the cell stack and returns to the respective tanks 2, 3 through outlets. The electrolytic solutions pass through pipes 8 and 9 (hereinafter referred to as "return pipes") when returning respectively. Do not attach a pump to this return line.

A control kit that detects and controls the degree of electrolyte charge (hereinafter referred to as "charge depth") and the temperature of the electrolyte in order to detect the voltage, current, and output of the cell stack for the operation of the entire battery. A battery control system (hereinafter referred to as "BMS") is installed as a The BMS controls the electrolyte by increasing or decreasing the rotation of pumps 6 and 7 . By controlling the pumps 6 and 7, the BMS sets the flow velocity and flow rate so that the electrolyte flows gently and uniformly in the cell stack 1, and controls the entire system.

When the electrolyte tank is installed in the lower part of the hull, etc., the cell stack must be installed in the upper part when viewed from the vertical direction (hereinafter referred to as "Y-axis"), and the height of the Y-axis is , 2nd deck or 3rd deck. It does not matter which position the control chamber is placed through the electrical wiring from the cell stack, but the shorter the Y-axis height of the cell stack and the electrolytic solution circulation system, the better, but preferably within 10 meters. Electrolyte tanks, on the other hand, can vary in volume and position to some extent for draft and trim adjustments, but cell stacks cannot be repositioned once installed. The weight ratio of the cell stack to the electrolyte increases as the cruising distance of the ship increases. For example, in Vessel Example 1, when a cell stack capable of outputting 1 MW is installed, the weight of the electrolytic solution is about 5 to 6 tons regardless of the cruising distance. If the cruising distance is 1,000 kilometers, 50 KL of electrolyte for 1 MWh is required, but if it is 7,000 kilometers, 350 KL is required. That is, the electrolytic solution can be calculated based on the conventional ballast water draft standard, but the newly installed cell stack is installed in consideration of the draft of the ship and the effects of trim adjustment.

FIG. 2 is a diagram showing the new battery system when installing the electrolyte tank in the ballast water area.
In the new battery system, the liquid feed pipes 4 and 5 between the cell stack 1 and the electrolyte tank are not connected by pipes of the same inner diameter or other size, but a tank that temporarily receives and stores the electrolyte on the way (hereinafter referred to as "buffer tanks") 10, 11, and separate liquid feed pipes 12, 13 connected to electrolytic solution tanks 2, 3 (hereinafter referred to as "main tanks") below them, and pumps 14, 15. and return lines 16,17. In the new battery system, the BMS 18 controls the feed pumps 14, 15 of the main tanks 2, 3. The main tanks 2, 3 can be placed in a space or in water or other liquid with an ambient temperature of 0°C to 35°C or less.

Buffer tanks 10, 11 and pumps 14, 15 are installed at a certain height, the flow rate of the electrolyte is reduced to zero, and the electrolyte is supplied to the cell stack by connecting to the liquid feed pipes 4, 5 having a small inner diameter above them. laminar flow and sent to the cell stack.

FIG. 3 is a diagram for explaining in detail the buffer tank in the case of the MW class battery system.
In the example shown in FIG. 3, only the negative electrolyte is shown in order to explain the piping in which the electrolyte coming up from the main tank 2 temporarily stops at the buffer tank 19 and is sent to the cell stack. . In addition, the concept of the diagram in Figure 3 is that the main tanks are placed in the ship's ballast water tanks, and the cell stacks, etc. are placed vertically above the main tanks or in the second or third deck. It is an assumption. The electrolyte is pumped up from the main tank 2 by the pipe 12 and the pump 14 and comes to the buffer tank 19. In the pipe 12, the flow becomes turbulent with a considerably high Reynolds number depending on the design value. The electrolyte flows into the cell stack at a reduced speed via a plurality of branched liquid transfer pipes rather than at the flow rate in the pipe 20 from the buffer tank 19 to the cell stack. Another purpose of the buffer tank 19 is to make the center of gravity of the hull as low as possible. Therefore, the buffer tank should be provided at a low position and should be light in weight.

In the example shown in FIG. 3, the size of the negative electrolyte buffer tank and the positive electrolyte buffer tank together provide a volume of flow that corresponds to the flow required for 5 minutes when the battery system is operating on a ship. Design to the same extent. For example, the flow rate of the electrolytic solution when the ship of Ship Example 1 is sailing is 800 L per minute. Therefore, the amount of negative and positive electrolyte pumped into the buffer tank in 5 minutes is 2,000 L negative and 2,000 L positive. The size of the buffer tank can be determined within a range corresponding to a flow rate of 3 to 6 minutes.

The double circle at the upper end of the pipe 20 extending upward from the buffer tank 19 shown in FIG. 3 continues to the double circle of the same pipe 20 shown in FIG. Also, the electrolytic solution feeding pipe such as the pipe 20 may be a plurality of pipes having a small cross-sectional area, but the total electrolytic solution feeding amount is not changed.

FIG. 4 is a diagram showing a battery system with an output of 1 MW.
In the example shown in FIG. 4, four cell stacks with an output of 250 kW are arranged, and the negative electrolytic solution is supplied from the pipe 20 by the pump 21 to the cell stack groups 22 and 23, and simultaneously to the cell stack groups 24 and 24 on the right side. 25 is also fed by the pump 26 . On the other hand, the positive electrolyte rises from buffer tank 19 shown in FIG. Pumps 28 and 29 feed the electrolytic solution that has risen up to all four sets of cell stacks 22, 23, 24 and 25 (four sets).

A case where the main tank is installed at a position where ballast water is stored will be described.
FIG. 5 is a diagram showing a battery system with a C tank.
When an electrolyte tank is installed at a position where ballast water is stored, it is conceivable that the size and shape of the tank may vary depending on the location, and that the tank may not be on the same plane and may have steps. Therefore, in case a single main tank cannot cope with the problem, a plurality of tanks having a certain size are determined, and a C tank is set, which is divided into negative and positive electrolytic solution tanks. In the example shown in FIG. 5 as well, the role of feeding the electrolyte to the cell stack remains unchanged from the main tank. In the example shown in FIG. 5, the main tank 30 for the negative electrolytic solution has been described, and the illustration of the main tank for feeding the positive electrolytic solution has been omitted.

Even in cases such as the example shown in FIG. 4 for the 1 MW class, the return electrolyte that has passed through the cell stack flows directly into the main tank and C tanks 31 and 32 without a pump. Here, the C tanks 31 and 32 receive the electrolytic solution through the return pipes 35 and 36 from the cell stack and transfer it to the main tank 30 again. When the electrolyte is returned to the main tank 30, the C tanks 31 and 32 are equipped with pumps 33 and 34 and backflow prevention valves 37 and 38, respectively. The reason for this is to ensure that there is no non-uniformity in the ion concentration of the returned electrolytic solution and that of the electrolytic solution to be sent from this. The reason is as follows.
At the time of discharge, the negative electrolyte solution has a reaction of V ²⁺ →V ³⁺ of vanadium ions, and divalent ions decrease,
In the positive electrolyte, pentavalent ions decrease in the reaction of V ⁵⁺ →V ⁴⁺ .
During charging, the opposite reaction occurs in both. In this reaction, each time the cell stack passes through, for example, the ratio of divalent and trivalent ions changes at the negative electrode. need to mix. There is no test research report on equalization in the electrolytic solution for reference in the unprecedented case shown in FIG. For example, if the main tank has a capacity of 20 times or more of the electrolytic solution sent per minute, there is no particular need to stir.

The main purpose is to install a tank that stores electrolyte at the position of the ballast water tank on board and use it to supply power, but on many ships, half of the ballast water determined when empty With electrolyte equivalent to the following (volume calculation), cruising distance of 7,000 kilometers is possible. In that case, the rest of the ballast water can be replaced with the electrolytic solution.

The electrolyte may have a specific gravity in the range of 0.5 to 1.5. For example, when the specific gravity is 1.0, it is replaced with the same volume of ballast water. No need to dispose, clean, replace or recharge. The replacement electrolyte for ballast water is preferably left uncharged (hereinafter referred to as "non-charged electrolyte"). If the ship is fully loaded and no draft weight is required, the uncharged electrolyte can be stored at port and used on another empty ship.

Batteries on board should be charged before sailing, unless electricity is generated on board.
There are two methods. One is charging in the normal way at the port of departure, and the other is just the electrolyte (hereinafter referred to as "charged electrolyte") previously charged somewhere on land using a separate cell stack. is injected into the onboard electrolyte tank. The charged electrolyte can be placed in a sealed container and injected into a tank onboard a ship using a tube for transporting the electrolyte during land transportation or at a port. In the case of charged electrolyte (those that have not been charged in the same ship), be sure to record the charging conditions, such as at least the charging current, charging time, and charging depth, and record the data when discharging and using (hereinafter referred to as It is desirable to provide it to the ship's manager, etc. as a "charging record". When the ship sets sail, power can be obtained by discharging based on the charged electrolyte and the charge record. Once the ship is in port, the discharged electrolyte can be recharged in the normal way by operating the batteries on board, or the charged electrolyte charged on land and the discharged electrolyte during voyage can be used. Replace with a discharged electrolyte (hereinafter referred to as "discharged electrolyte"). When the depth of discharge of the discharged electrolyte is 90% or more, it may be treated in the same way as the non-charged electrolyte.

When generating power such as solar power on board, this battery can be used to charge the generated power on board. There are several precedents for using integrated batteries to generate power such as solar power on board. However, there is no report on the use of the integrated type and the present battery for application to the propulsion system (M/E) of ships.

In the case of this battery, it is used to generate renewable energy or other shipboard power generation (hereinafter referred to as "shipboard power generation") and store it. In particular, for renewable energy (hereinafter referred to as "RE"), all generated power is not stored, but a part of it is stored and the rest can be directly used by electrical control technology.

Among the RE, it is assumed that full-scale onboard power generation will be possible for those that want to use solar power (hereinafter referred to as "PV") in the future. When the power generation efficiency of PV reaches 30%, in Ship Example 1, if the area where PV panels or PV sheets are attached is 500 square meters or more, 1 MWh of power can be obtained under the conditions of sunshine hours comparable to those in the Kanto region of Japan. When storing this, the electrolyte is 50 KL, which is 1/7 of 700 KL of unloaded ballast water, and charging and discharging can be performed at all times. When the PV power is directly used during the sunshine hours on board, the required electrolytic solution may be 50 KL or less. Such methods are most desirable in ship electrification.

In a vanadium flow battery, which is one type of flow battery, the flow rate of the electrolyte in the cell stack is adjusted so that, for example, the entire surface of A4 size paper can be evenly passed through at right angles. The above analogy, the paper surface, means the electrode in the cell stack. The electrode is a sponge-like plate made of graphite material, and its thickness is several millimeters. It is a structure in which an ionic reaction occurs when an electrolytic solution passes through it, and a specific reactant therein diffuses into the ion exchange membrane. Therefore, it is necessary to verify the flow of the electrolyte in the cell stack because rolling in the near sea and pitching in the offshore are constantly occurring in the ship.

For this reason, another issue in electrifying ships with batteries is how the function of the batteries changes when the ship shakes. In the following experiments and verifications, experiments were conducted assuming three cases in which the ship's swaying period was short (less than 1 minute), long (longer than 1 minute), and for some reason the ship remained tilted for a long period of time. This led to conditions that did not interfere with However, the inclination of the center of gravity axis of the ship due to rocking etc. was set within 35 degrees.

"Experiment and Verification"
Test conditions;
(1) Cell stack; Commercial stack with 40 cells stacked with an ionization reaction cross-sectional area of 493 square meters (2) Specifications on flat ground, electrolyte flow rate from 3 L to 6 L per minute (3) At an inclination of 35 degrees Charge and discharge test continuously for 20 hours,
Test for flow rates of 7 L, 4 L, and 2 L per minute. However, at the beginning of the test, short period shaking and long period shaking were performed twice each.
(4) Test temperature: room temperature (5) Electrolyte: vanadium metal - 1.6 mol, sulfuric acid concentration 2.0 mol.
(6) 43A charge, cutoff at 64V, rated voltage is 60V.

Result: Calculated with Ah of storage capacity for each test. However, the theoretical value of the electrolyte is 26.8 Ah/mole, L. Use 15 L (negative and positive combined 30 L) electrolyte for testing (1) 7 L / min; 215 Ah
(2) 4 L/min: 430 Ah
(3) 2 L/min; 399 Ah
No abnormalities were observed in short period and long period shaking of 2 minutes.

consideration, verification;
At a 35 degree tilt, the height of the cell stack associated with the electrolyte delivery head is 23 centimeters, which is 4 centimeters lower. If this is taken as the flow velocity head ratio, it will be 1.01 times faster.
Since the specification of the same cell stack on flat ground is 3 to 6 liters per minute, 7 liters per minute is too much considering the test conditions, but in the case of 2 liters, the flow rate is insufficient even considering the slope. , The reason why the charge capacity did not deteriorate greatly is that the speed of the electrolyte in the cell moves through the porous electrode at 1.7 mm per second. This is thought to be due to the influence of the retained electrolyte.
For the same reason, short period shaking and long period shaking of about 2 minutes seem to have no effect.

Conclusion;
In a ship, the flow rate of the electrolytic solution is determined as follows for shaking and the like.
Flow rate: 3 L to 5.5 L per minute without limiting battery operation time.

It should be noted that the present invention is not limited to the above-described embodiments, and includes modifications, improvements, etc. within the scope of achieving the object of the present invention.

1, 22, 23, 24, 25 Cell stack 2, 3, 30 Main tank (electrolyte tank)
4, 5, 12, 13 liquid feeding pipes 6, 7, 14, 15, 21, 26, 28, 29, 33, 34 pumps 8, 9, 16, 17, 20, 27, 35, 36 pipes 10, 11, 19 Buffer tanks 31, 32 C tanks 37, 38 Backflow prevention valve

Claims (9)

In the flow battery used on board,
a cell stack;
a main tank connected to the cell stack via a pipe and containing an electrolytic solution;
The electrification system for a ship, wherein the main tank is installed at or near a place for storing ballast water in the ship. When the main tank is installed in a place where ballast water is stored, the amount of ballast water should be reduced by the weight of the electrolyte stored in the main tank, or the entire amount of ballast water should be replaced with electrolyte. 2. The vessel electrification system according to claim 1, wherein the electrolytic solution is used for draft adjustment. a buffer tank provided between the cell stack and the main tank and connected to the cell stack and the main tank via a pipe;
a pump that delivers electrolyte from the main tank to the buffer tank;
3. The electrification system for a ship according to claim 1, wherein the electrolyte is sent from the main tank to the buffer tank by the pump, and the flow rate of the electrolyte sent to the cell stack is suppressed. a first fluid control unit that controls the flow of electrolyte from the main tank toward the cell stack;
4. The vessel electrification system according to any one of claims 1 to 3, further comprising a second fluid control section that controls a flow of electrolyte from said cell stack toward said main tank. 4. The vessel electrification system according to claim 3, wherein said buffer tank has an electrolyte storage capacity of 1/10 or less of said main tank. Further comprising a C tank provided between the cell stack and the main tank and connected to the cell stack and the main tank via a pipe,
5. The apparatus according to claim 4, wherein the second fluid control unit sends the electrolyte discharged from the cell stack to the C tank, and sends the electrolyte stored in the C tank to the main tank. Ship electrification system. When the draft and trim of the ship are adjusted using an electrolytic solution, the second fluid control unit controls a pump that moves the electrolytic solution for adjusting the draft and trim of the ship. Item 5. The vessel electrification system according to Item 4. 8. The vessel electrification system according to any one of claims 1 to 7, wherein the charged electrolyte charged outside the vessel can be used. 9. The vessel electrification system according to any one of claims 1 to 8, wherein the electrolyte has a specific gravity of 0.8 or more and 1.8 or less.

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