KR20230148507A - Battery thermal management system of ship - Google Patents

Abstract

The present invention is a battery thermal management system for a ship, and in more detail, includes a storage tank unit storing ballast water therein, a battery unit provided within a wall of the storage tank unit, and the wall heated by the battery unit is The battery unit is cooled as it is cooled by the ballast water.

Description

Battery thermal management system of ship}

The present invention relates to a ship's battery thermal management system, and more specifically, to a ship's battery thermal management system that maintains a constant temperature of the battery using ballast water or sea water.

Recently, electric propulsion ships have been developed that drive propulsion devices such as propellers by rotating propulsion motors with electrical energy. For example, Republic of Korea Patent No. 10-1916147 (2018.11.05.) discloses information on a vertical axis impeller blade propulsion device for electric propulsion ships.

Such electric propulsion ships and other ships are equipped with batteries that supply power to electrical equipment, and in particular, electric propulsion ships require a cooling device to prevent the batteries from heating up. However, in the conventional case, there were several problems such as reduced space utilization of the ship and increased cost as separate refrigerants and heat exchange devices were provided for heat management of the battery.

Republic of Korea Patent No. 10-1916147 (2018.11.05.)

The present invention was conceived to solve the problems of the prior art as described above, and its purpose is to provide a ship battery thermal management system that maintains the temperature of the battery constant using ballast water or sea water.

The problems to be solved by the present invention are not limited to the problems mentioned above, and other problems to be solved by the present invention that are not mentioned herein can be explained to those skilled in the art from the description below. You will be able to understand it clearly.

In the battery thermal management system for a ship according to a preferred embodiment of the present invention, it includes a storage tank unit for storing ballast water therein, a battery unit provided within a wall of the storage tank unit, and heat generated by the battery unit. The battery unit is cooled as the wall is cooled by the ballast water.

In addition, the storage tank unit according to a preferred embodiment of the present invention includes a communication pipe that communicates the inside of the storage tank unit and the inside of the wall, and the ballast water can flow between the inside of the storage tank unit and the wall. It is characterized by

In addition, the communication pipe according to a preferred embodiment of the present invention is provided in at least two pieces, and the ballast water heated by the battery unit is provided into the storage tank unit through the communication pipe provided relatively above among the two communication pipes. As it flows, the ballast water circulates within the storage tank portion and walls.

In addition, the storage tank unit according to a preferred embodiment of the present invention further includes a circulation pump that is provided on one side of the storage tank unit and causes the ballast water to circulate inside and inside the wall of the storage tank unit through the communication pipe. It is characterized by

In addition, the storage tank unit according to a preferred embodiment of the present invention is provided on one side of the storage tank unit, flows ballast water inside the storage tank unit to the outside of the ship, and transfers seawater outside the ship to the storage tank unit. It is characterized by including a replacement pump that flows inside.

As a means of solving the above problem, the ship's battery thermal management system of the present invention has a compact configuration in which a plurality of battery units are provided within the wall of the storage tank, and can increase space utilization for ships with limited space, and can be installed on ships. There is an advantage in that the battery section can be cooled without additional configuration or power by using essential ballast water.

In addition, the ship's battery thermal management system of the present invention can store ballast water not only in the depression but also in the space within the wall, compared to the conventional method in which ballast water is stored only inside the storage tank, thereby securing more storage space for ballast water. There are benefits to this.

In addition, the ship's battery thermal management system of the present invention allows ballast water whose temperature has risen by the battery section to flow toward the depression through the first communication pipe provided on the upper side of the wall, and to store the relatively low temperature stored in the depression. As the ballast water flows inside the wall through the second communication pipe, the ballast water circulates through natural convection, which has the advantage of improving cooling efficiency for the battery unit.

In addition, the ship's battery thermal management system of the present invention has the advantage of maintaining cooling efficiency for the battery section by minimizing the temperature rise due to overall heating of the ballast water even when operated for a long time through seawater (W).

In addition, the ship's battery thermal management system of the present invention forcibly flows and circulates ballast water through a circulation pump to prevent the circulation of ballast water from stagnating due to poor natural convection due to temperature difference, thereby controlling the battery portion. There is an advantage in improving cooling efficiency.

In addition, the ship's battery thermal management system of the present invention is configured to replace the ballast water inside the storage tank with seawater, thereby minimizing the overall heating of the ballast water and temperature rise in the battery section even during long-term operation. There is an advantage in maintaining cooling efficiency.

In addition, the ship's battery thermal management system of the present invention can improve the cooling efficiency of the battery section by operating the circulation pump and replacement pump based on the temperature of the battery section and the temperature of the ballast water, and quickly detect mechanical defects. There are benefits to doing this.

The effects of the present invention are not limited to the effects mentioned above, and the effects of the present invention not mentioned herein will be clearly understood by those skilled in the art from the description below. .

Figure 1 is a cross-sectional view showing the configuration of a ship's battery thermal management system according to an embodiment of the present invention.
Figure 2 is a cross-sectional view showing the configuration of a ship's battery thermal management system according to another embodiment of the present invention, showing a communication pipe formed on the wall of the storage tank.
Figure 3 is a cross-sectional view showing the configuration of a ship's battery thermal management system according to another embodiment of the present invention, showing a plurality of communication pipes arranged along the wall of the storage tank.
Figure 4 is a cross-sectional view showing the configuration of a ship's battery thermal management system according to another embodiment of the present invention, showing a heat pipe formed to cool the wall of the storage tank through seawater.
Figure 5 is a cross-sectional view showing the configuration of a ship's battery thermal management system according to another embodiment of the present invention, showing the circulation pump formed.
Figure 6 is a cross-sectional view showing the configuration of a ship's battery thermal management system according to another embodiment of the present invention, showing the replacement pump formed.
Figure 7 is a cross-sectional view showing the configuration of a ship's battery thermal management system according to another embodiment of the present invention, showing a plurality of communication pipes arranged along the wall of the storage tank and a circulation pump and a replacement pump formed.
Figure 8 is a diagram showing the control configuration of a ship's battery thermal management system according to another embodiment of the present invention.
Figure 9 is a flowchart showing a control method of a ship's battery thermal management system according to another embodiment of the present invention.
Figure 10 is a cross-sectional view showing the configuration of a ship's battery thermal management system according to another embodiment of the present invention, showing a battery installed on the internal bulkhead of the ballast water storage tank.
Figure 11 is a plan view showing the configuration of a ship's battery thermal management system according to another embodiment of the present invention, showing a battery provided on the internal bulkhead of the ballast water storage tank.

The terms used in this specification will be briefly explained, and the present invention will be described in detail.

The terms used in the present invention are general terms that are currently widely used as much as possible while considering the function in the present invention, but this may vary depending on the intention or precedent of a person working in the art, the emergence of new technology, etc. Therefore, the terms used in the present invention should be defined based on the meaning of the term and the overall content of the present invention, rather than simply the name of the term.

When a part in the entire specification is said to “include” a certain element, this means that it does not exclude other elements but may further include other elements, unless specifically stated to the contrary.

Below, with reference to the attached drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein.

Specific details, including the problem to be solved by the present invention, the means for solving the problem, and the effect of the invention, are included in the examples and drawings described below. The advantages and features of the present invention and methods for achieving them will become clear by referring to the embodiments described in detail below along with the accompanying drawings.

Hereinafter, the present invention will be described in more detail with reference to the attached drawings.

Referring to FIG. 1, in the ship's battery thermal management system according to a preferred embodiment of the present invention, a storage tank unit 100 that stores ballast water (E) therein, and a storage tank unit 100 of the storage tank unit 100. It includes a battery unit 200 provided within the wall 101, and as the wall 101 heated by the battery unit 200 is cooled by the ballast water E, the battery unit 200 Allow to cool.

First, the storage tank unit 100 is prepared. For example, the storage tank unit 100 includes a wall 101 and a depression 102. At this time, the wall 101 may be composed of a bottom wall and a side wall excluding the upper surface in a form that surrounds the depression 102. And, an empty space in which the battery unit 200 can be provided is formed within the wall 101. Additionally, the depression 102 refers to an empty space provided inside the wall 101, and the ballast water E is stored in the depression 102.

Next, the battery unit 200 is prepared. The battery unit 200 may be provided in plural pieces. For example, the battery unit 200 is a set of positive and negative plates combined, and is separated from other cells by being immersed in an electrolyte in a case made of one compartment. It includes a battery cell 201 and a fixing part 202 that allows the battery cell 201 to be fixed within the wall 101. In addition, the fixing part 202 can be provided in any shape as long as the battery cell 201 can be fixed within the wall 101. For example, the fixing part 202 can be used to attach the battery cell 201 to the wall 101. It can be coupled and released at both ends of the case using screws, etc., and can be provided to be fixed to the inner peripheral surface of the wall 101. In addition, the wall 101 and the fixing part 202 may be manufactured using a material with high thermal conductivity. For example, the fixing part 202 is made of materials such as aluminum, copper, and structural steel, so that heat from the battery cell 201 is transferred to the wall 101.

Meanwhile, the battery unit 200 gradually heats up as power is supplied to the ship, making cooling of the battery unit 200 essential. For example, lithium ion batteries can be used at temperatures from 0 to 60 degrees, and the temperature for optimal performance is 15 to 40 degrees. In addition, the ballast water of ships usually uses seawater, and the average seawater temperature around the world is about 3.5 degrees, the average water temperature in the East Sea in Korea is 8.6 degrees to 15.9 degrees, and the average water temperature in the South Sea is 15.7 degrees to 18.8 degrees. Therefore, it is suitable to use the ballast water to cool the heated battery unit 200.

In other words, when heating according to the operation of the battery unit 200, heat exchange occurs between the battery unit 200 and the wall 101, and the wall 101 heated by the battery unit 200 Cooled by the ballast water (E). That is, the battery unit 200 is cooled by the ballast water (E) stored inside the storage tank unit 100.

As a result, the plurality of battery units 200 are provided in a compact configuration within the wall 101 of the storage tank unit 100, which improves space utilization for ships with limited space and provides essential components for ships. There is an advantage in that the battery unit 200 can be cooled using ballast water without additional configuration or power.

On the other hand, referring to FIG. 2, the storage tank unit 100 includes a communication pipe 110 that communicates the inside of the storage tank unit 100 and the wall 101, and the ballast water E is It is possible to flow inside the storage tank portion 100 and the wall 101. The communication pipe 110 can be formed in any shape as long as it can communicate with the interior of the storage tank unit 100 and the space within the wall 101, and may also be provided in the form of a hole. Likewise, the inside of the storage tank 100 refers to the depression 102, and a space in which the ballast water E can be stored and flows is formed within the wall 101. At this time, the case of the battery cell 201 may be made of a waterproof material. That is, as the ballast water (E) directly contacts the battery unit 200 provided in the wall 101, the cooling efficiency of the battery unit 200 increases.

At this time, the communication pipes 110 are provided in at least two pieces, and the ballast water E heated by the battery unit 200 flows through the communication pipe 110 provided on the relatively upper side of the two communication pipes 110. As it flows into the storage tank unit 100, the ballast water (E) circulates within the storage tank unit 100 and the wall 101. For example, referring to FIG. 2, the ballast water (E) heated by the plurality of battery units 200 flows to the upper part of the wall 101, and accordingly, one of the two communication pipes 110 It flows toward the depression 102 through the first communication pipe 111 provided relatively above. At the same time, ballast water (E) with a relatively low temperature flows into the wall 101 through the second communication pipe 112 provided on the relatively lower side of the two communication pipes 110.

As a result, the ballast water (E) whose temperature has been raised by the battery unit 200 flows toward the depression 102 through the first communication pipe 111 provided on the upper side of the wall 101, and As the relatively low temperature ballast water (E) stored in the depression 102 flows inside the wall 101 through the second communication pipe 112, the ballast water (E) circulates. , there is an advantage that the cooling efficiency of the battery unit 200 can be improved.

And, referring to FIG. 3, the communication pipes 110 may be arranged in plural numbers along the wall 101. That is, by allowing the ballast water (E) to flow more actively through the plurality of communication pipes 110, the time required for circulation is reduced and the cooling efficiency of the battery unit 200 is further improved. To make it happen. In addition, compared to the conventional method of storing only inside the storage tank, the ballast water (E) can be stored not only in the depression 102 but also in the space within the wall 101, as in the present invention, and the ballast water ( E) has the advantage of securing more storage space.

And, referring to FIG. 4, the battery unit 200 may be cooled by using seawater (W) on the outside of the hull side wall (A). More specifically, when the storage tank unit 100 is provided adjacent to the hull side wall (A), the wall 101 heated by the battery unit 200 exchanges heat with the hull side wall (A). Accordingly, cooling of the wall 101 can be achieved. In other words, the hull side wall (A) is cooled by the sea water (W), and the wall 101 is cooled according to heat exchange between the relatively high temperature wall 101 and the hull side wall A. , the ballast water (E) inside the storage tank unit 100 and the wall 101 can be cooled. For example, in the case of an electric propulsion ship, the battery unit 200 is operated for a long time, and as the temperature of the ballast water (E) inside the storage tank unit 100 and the wall 101 increases overall, the battery unit 200 There is a risk that efficiency will decrease. In order to prevent this, the inside of the long tank 100 and the ballast water (E) within the wall 101 can be cooled by reducing the temperature of the wall 101 using the seawater (W). At this time, in order to improve the cooling efficiency of the ballast water (E) through the seawater (W), a plurality of heat pipes 134 may be provided between the storage tank portion 100 and the hull side wall (A). That is, heat exchange can be performed more actively between the hull side wall (A) and the wall 101 through the plurality of heat pipes 134. In other words, as heat exchange is performed through the heat pipe 134 connecting the storage tank 100 with the lower hull wall and side wall (A) in contact with the seawater (W), the seawater (W) The wall 101 of the storage tank 100 can be cooled. That is, the wall 101 heated by the battery unit 200 is cooled by the ballast water (E) and sea water (W).

As a result, there is an advantage in that the cooling efficiency of the battery unit 200 can be maintained by minimizing the temperature increase due to overall heating of the ballast water (E) even when operating for a long time using the sea water (W).

On the other hand, referring to FIG. 5, the storage tank unit 100 is provided on one side of the storage tank unit 100, and the ballast water (E) flows through the communication pipe 110 into the storage tank unit ( It may further include a circulation pump 120 that provides driving force to circulate within the interior and wall 101 of 100). That is, the circulation pump 120 may be provided in plural, and may cause the ballast water (E) stored in the depression 120 to flow into the wall 101, or the ballast water within the wall 101 ( E) is to flow toward the depression 120. In other words, in order to prevent the circulation of the ballast water (E) from stagnating due to poor natural convection due to temperature difference, the ballast water (E) is forced to flow through the circulation pump (120) and the battery unit. (200) There is an advantage in improving the cooling efficiency.

On the other hand, referring to FIG. 6, the storage tank unit 100 is provided on one side of the storage tank unit 100, and the ballast water (E) inside the storage tank unit 100 is stored in the vessel. It may further include a replacement pump 130 that flows to the outside and flows seawater (W) outside the ship into the inside of the storage tank unit 100. That is, the replacement pump 130 discharges the ballast water (E) stored in the depression 102 to the outside and supplies seawater (W) to the depression 102 to replace the ballast water (E) as a whole. performs its role. For example, the storage tank unit 100 further includes a pipe 132 communicating between the inside of the storage tank unit 100 and the outside of the hull, and a valve 131 provided on one side of the pipe 132. And, with the valve 131 open, the ballast water (E) inside the storage tank unit 100 can be discharged and sea water (W) can be introduced by driving the replacement pump 130. . At this time, the replacement pump 130 may be provided in plural numbers, and the pipes 132 may also be provided in plural numbers, and a pipe for discharging ballast water (E) and a pipe for supplying sea water (W) may be provided. . In addition, the plurality of pipes 132 are provided at a point adjacent to the highest water level of the ballast water (E) inside the storage tank unit 100, and the remaining pipes 132 are located on the bottom of the storage tank unit 100. It can be provided. That is, the control unit 400, which will be described later, first performs the exchange of ballast water (E) and sea water (W) through the pipe 132 adjacent to the highest water level surface of the ballast water (E), which has a relatively high temperature. The overall temperature of the ballast water (E) inside the storage tank unit 100 can be reduced. Additionally, the valve 131 may be formed as an electromagnetic valve or a solenoid valve.

As a result, as the ballast water (E) inside the storage tank unit 100 is configured to be replaceable with seawater (W), the ballast water (E) is heated as a whole even during long-term operation, preventing the temperature from rising. By minimizing this, there is an advantage in maintaining the cooling efficiency of the battery unit 200.

On the other hand, referring to FIGS. 7 and 8, the ship's battery thermal management system of the present invention measures the temperature of the battery unit 200 or the ballast water (E) inside the storage tank unit 100. It may further include a sensor unit 300 that measures the temperature, and a control unit 400 that controls the circulation pump 120 or the replacement pump 130 based on the measured value of the sensor unit 300. More specifically, the sensor unit 300 includes a battery temperature sensor 310 that is provided inside the battery unit 200 to measure the temperature of the battery cell 201, and the inside of the storage tank unit 100. It includes a ballast water temperature sensor 320 that is provided and measures the temperature of the ballast water (E). In addition, the control unit 400 controls the circulation pump 120 based on the measured value of the battery temperature sensor 310, and controls the replacement pump 130 based on the measured value of the ballast water temperature sensor 320. ) is controlled.

At this time, the ballast water temperature sensor 320 may be installed at a point adjacent to the highest water level of the ballast water (E) inside the storage tank unit 100. That is, the ballast water temperature sensor 320 measures the highest temperature of the ballast water (E) inside the storage tank unit 100 due to a convection phenomenon. In other words, the ballast water temperature sensor 320 measures the temperature of the ballast water (E), which is heated and rises by the battery unit 200, and transmits the measured value to the control unit 400, so that the control unit ( 400) to determine the replacement time of the ballast water (E).

In addition, the ballast water temperature sensor 320 is at least two, one is provided at a point adjacent to the highest water level of the ballast water (E) inside the storage tank unit 100, and the other is provided in the storage tank unit ( 100) It can be provided on the bottom of the interior. That is, among the ballast water temperature sensors 320, the ballast water temperature sensor 320 provided at a point adjacent to the highest water level of the ballast water (E) inside the storage tank unit 100 is the The highest temperature is measured, and the ballast water temperature sensor 320 provided on the bottom of the storage tank 100 measures the lowest temperature of the ballast water (E). That is, when the difference value between the highest and lowest temperatures of the ballast water (E) exceeds a preset value, the control unit 400 replaces the ballast water (E) with sea water (W) through the replacement pump 130. ) can be controlled to replace it. In addition, a plurality of battery temperature sensors 310 may be provided to correspond to at least one battery unit 200 .

Hereinafter, a method of cooling the heat of the battery unit 200 using the ship battery thermal management system of the present invention will be described in detail with reference to the attached drawings.

Referring to FIG. 9, first, the temperature of the battery cell 201 is measured through the battery temperature sensor 310. Here, the control unit 400 determines whether the measured value of the battery temperature sensor 310 exceeds a preset value. At this time, when the control unit 400 determines that the measured value of the battery temperature sensor 310 does not exceed the preset value, the battery temperature sensor 310 measures the temperature of the battery cell 201 again. do. In addition, when the control unit 400 determines that the measured value of the battery temperature sensor 310 exceeds a preset value, the circulation pump 120 operates to increase the ballast water E in the wall 101. By allowing it to flow inside the storage tank unit 100, the ballast water E stored inside the storage tank unit 100 is controlled to flow into the wall 101. That is, the control unit 400 allows the ballast water (E) to circulate through the circulation pump 120 when natural convection is not smooth. In addition, after the circulation pump 120 is operated and a preset time has passed, the temperature of the battery cell 201 is measured again through the battery temperature sensor 310. Here, the control unit 400 determines again whether the measured value of the battery temperature sensor 310 exceeds a preset value. At this time, when the control unit 400 determines that the measured value of the battery temperature sensor 310 does not exceed the preset value, the temperature of the battery cell 201 is first measured through the battery temperature sensor 310. Return to the measurement stage. That is, the control unit 400 determines that the battery cell 201 has been sufficiently cooled through the circulation of the ballast water (E), and after a preset time has elapsed, the battery temperature sensor 310 detects the battery cell 201. Measure the temperature of (201). In addition, when the control unit 400 determines that the measured value of the battery temperature sensor 310 exceeds a preset value, the ballast water temperature sensor 320 detects the ballast water inside the storage tank unit 100 ( Measure the temperature of E). Here, the control unit 400 determines whether the measured value of the ballast water temperature sensor 320 exceeds a preset value. At this time, when the control unit 400 determines that the measured value of the ballast water temperature sensor 320 exceeds the preset value, the replacement pump 130 is operated to operate the ballast water ( E) is discharged to the outside, and seawater (W) is allowed to flow into the storage tank unit 100. That is, the control unit 400 causes the ballast water (E) of the storage tank unit 100 to be replaced. In addition, when the control unit 400 determines that the measured value of the ballast water temperature sensor 320 does not exceed the preset value, an alarm signal is generated and an alarm is sent to the manager's terminal so that the manager can perceive it through the five senses. Send a text message. That is, since the battery cell 201 is in a heated state and the ballast water (E) is not heated, the control unit 400 detects a malfunction of the circulation pump 120 and the storage tank unit 100. It generates an alarm signal due to mechanical defects such as damage such as cracks.

As a result, the cooling efficiency for the battery unit 200 is increased by operating the circulation pump 120 and the replacement pump 130 based on the temperature of the battery unit 200 and the temperature of the ballast water (E). can be improved and has the advantage of quickly detecting mechanical defects.

On the other hand, referring to FIG. 10, the storage tank unit 100 may further include a plurality of partition walls 103 that partition the interior of the storage tank unit 100. At this time, the plurality of partition walls 103 serve to prevent the ballast water (E) stored inside the storage tank unit 100 from being tilted in one direction. For example, the bulkhead 103 prevents the ballast water (E) from escaping from the storage tank unit 100 due to fluctuations of the hull, such as rolling, pitching, and melting.

Here, the battery unit 200 may be provided within the partition wall 103. In other words, the battery unit 200 is provided not only within the wall 101 of the storage tank unit 100, but also within the partition wall 103, so that a greater number of battery units 200 can be stored within a limited space. It has the advantage of being compactly deployed. In addition, the partition wall 103 may be provided with a plurality of communication pipes 110 that communicate within the partition wall 103 and the storage tank unit 100, and the circulation pump 120 and the replacement pump 130 It is natural that can be provided. Additionally, the partition wall 103 has the advantage of preventing the battery unit 200 from being heated as it is cooled by the ballast water (E). In other words, the plurality of battery units 200 are compactly configured to be provided within the wall 101 and the bulkhead 103 of the storage tank unit 100, making it possible to increase space utilization for ships with limited space. There is an advantage that the battery unit 200 can be cooled using ballast water (E), which is essential for ships.

As such, a person skilled in the art will understand that the technical configuration of the present invention described above can be implemented in other specific forms without changing the technical idea or essential features of the present invention.

Therefore, the embodiments described above should be understood in all respects as illustrative and not restrictive, and the scope of the present invention is indicated by the claims described later rather than the detailed description above, and the meaning and scope of the claims and their All changes or modified forms derived from the equivalent concept should be construed as falling within the scope of the present invention.

100: Storage tank part
101: wall
102: depression
103: Bulkhead
110: flue pipe
111: 1st communication pipe
112: Second communication pipe
120: circulation pump
130: Replacement pump
131: valve
132: tube
134: heat pipe
200: Battery part
201: battery cell
202: fixing part
300: sensor unit
310: Battery temperature sensor
320: Ballast water temperature sensor
400: control unit
E: Ballast water
W: seawater
A: Hull side wall

Claims (5)

A storage tank unit that stores ballast water therein; and
It includes a battery unit provided within the wall of the storage tank unit,
A ship's battery thermal management system, wherein the battery unit is cooled as the wall heated by the battery unit is cooled by the ballast water. According to paragraph 1,
The storage tank part,
It includes a communication pipe that communicates the inside of the storage tank unit and the inside of the wall,
A ship's battery heat management system, characterized in that the ballast water can flow within the interior and walls of the storage tank. According to paragraph 2,
The communication pipe is provided in at least two pieces, and as the ballast water heated by the battery unit flows into the storage tank unit through the communication pipe provided on a relatively upper side of the two communication pipes, the ballast water flows into the storage tank unit. A ship's battery thermal management system characterized by circulation within the interior and walls. According to paragraph 2,
The storage tank part,
A circulation pump is provided on one side of the storage tank unit and causes the ballast water to circulate within the interior and walls of the storage tank unit through the communication pipe. According to paragraph 1,
The storage tank part,
a replacement pump provided on one side of the storage tank unit, which flows ballast water inside the storage tank unit to the outside of the ship and flows seawater outside the ship into the storage tank unit; Battery thermal management system.