Japanese Submarine LIBs Program Documents

wispywood2344, on September 11, 2022, made very interesting comments and provided Japanese language documents (now translated by Pete) regarding the developments of Japan's Submarine Lithium-ion Batteries (LIBs) Program from 2006 out to 2023.

COMMENTS

The Japanese Ministry of Defense's (MoD's) Technical Research and Development Institute (TRDI) (see the present MoD Acquisition Technology & Logistic's Agency (ATLA) pointed out that the advantages of Lithium-ion Batteries (LIBs) over Lead-acid Batteries (LABs) are not only that more than twice energy density for LIBs, but also higher charging speeds, and also that more than 1.5 times more charge-discharge cycles in the LIBs' lifetime. [1] 

This means that compared to LABs, LIBs can handle 3 (=2x1.5) times more energy until they need to be replaced.

If the total amount of energy handled in a year is equivalent, the battery replacement frequency of LIBs can be less than 1/3 of the replacement frquency than LABs. 

Then, Let's consider the impact of this on the Japanese Navy aka Japanese Maritime Self Defense Force (JMSDF) submarine fleet. In addition to the effect of the 1.33(=640 LIBs/480 LABs) times increase in the number of LIBs  units installed [2], the frequency of battery replacement in the JMSDF LIBs submarine [the Taigeis and the Soryu's Oryu and Toryu] will be less than 1/4 of that in the conventional JMSDF LABs submarines [all the Soryus (except Oryu and Toryu) and all the Oyashios]. See Table [5] at the end of this article.

The JMSDF LABs submarines experience battery replacement once every 6 years.

So it can be expected that the JMSDF LIBs submarines will need LIBs replacement  once every 24 years. What is noteworthy is that this is almost equal to the lifetime of a JMSDF submarine.

In other words, there is a strong possibility that the JMSDF LIB submarines will not experience any battery replacement until their decommission. 

As battery technology continues to advance [3], the current submarine LIBs formula/types are expected to become obsolete in the future.

Eliminating the need for battery replacement would eliminate the need to procure technologically-obsolete batteries for replacements, thereby rationalizing the procurement of submarine batteries. Also see Document [4] and Table [5].

DOCUMENTS

[1]  A Japanese document translated by Pete https://warp.da.ndl.go.jp/info:ndljp/pid/11339364/www.mod.go.jp/j/approach/hyouka/seisaku/results/18/jigo/honbun/jigo05_honbun.pdf 

Fiscal 2006 Policy Evaluation Report (Ex-post project evaluation)

Department in charge: the Technical Planning Office, Department of Accounting and Equipment

Implementation period: October 2006 to March 2007

Project name: Research on new main storage batteries for submarines

Policy system: Ⅰ-4-(2)-② Research (development)

Business description: As the main storage battery (Note 1) for next-generation submarines, we will conduct research on high-performance main storage batteries that will replace the lead-acid batteries (Note 2) currently in use.

Technical data.

(Note 1) Main storage battery: A general term for all storage batteries used as a power source for submarine propulsion and on-board auxiliary equipment.

(Note 2) Lead-acid battery: A storage battery composed of a lead dioxide positive electrode, a lead negative electrode, and an acidic aqueous solution.

Required expenses: about 4.6 billion yen [US$32.1 million]

○ Contents of evaluation

1 Purpose of business

Lithium batteries with high energy density (Note 5) can replace lead-acid batteries, which are heavy and bulky, complicated to handle, and have long snorkel charging times (Note 3).

The aim was to study the Muion secondary battery (Note 6) as a new high-performance main storage battery for submarines and to demonstrate its feasibility and effectiveness.

(Note 3) Snorkel charging time: A submarine takes in air from a snorkel that is exposed to the surface of the sea, and uses diesel power to charge the onboard storage battery.

Time to charge

(Note 4) Target strength: (Target Strength) An index that expresses the strength of the sound reflected from the target (strength of reflected sound/strength of incident sound)

(Note 5) Energy density: Amount of energy that can be generated per unit weight or volume

(Note 6) Lithium-ion secondary battery: Lithium ion and metal oxide for positive electrode, carbon-based material for negative electrode, organic solvent of lithium salt for electrolyte, capable of repeated use.

Battery

2 Achievements

(1) Achievement effect

By achieving the following technical items, we have established a technological base for using large, high-capacity lithium-ion secondary batteries as the main storage battery for submarines.

stood up. In addition, the submarine's anti-detection ability and maneuverability will be improved, its underwater endurance will be extended, its ability to evade attacks will be improved, and its maintainability will be improved.

We obtained technical data on the performance, safety and life of submarine main storage batteries that can contribute to the above.

A. Energy density

By adopting a lithium-ion secondary battery, we have realized a new storage battery with an energy density per weight volume that is more than double that of a lead-acid battery.

B. Charging efficiency

Compared to lead-acid batteries, lead-acid batteries can be charged more efficiently, and the decrease in electrical capacity (amount of electricity that can be discharged) due to high-rate discharge is reduced.

I confirmed that it is smaller than the battery.

C. Safety

It was confirmed that the designed safety can be ensured [against] overcharge, overdischarge, and external short-circuit conditions.

D. Number of charge/discharge repetitions [cycles]

It was confirmed that the number of charge-discharge repetitions was 1.5 times or more that of a lead-acid battery, and that the battery had excellent life characteristics.

(2) Achievement period

Research prototypes were started in 2002, and in-house tests were completed by 2005.

(3) Matters such as lessons learned

This research aims to increase the capacity of lithium-ion secondary batteries, which are being used more and more in the private sector, with a view to putting them into practical use.

Future action

In this research, we have confirmed the function and performance with the actual equipment in mind, and we are planning to install the results of this research in the submarine built in 2020. [This was achieved, with JS Oryu being Commissioned with LIBs in March 2020]

○ Other reference information

Configuration of the prototype ----------------------- Attachment 1

Technology comparison with domestic & foreign countries Attachment 2

[2]  The JMSDF specification "Submarine motor system (SMC-8B)" p.9

[3] A Japanese document translated by Pete with some difficulty https://warp.da.ndl.go.jp/info:ndljp/pid/11339364/www.mod.go.jp/j/approach/hyouka/seisaku/results/30/pdf/jizen_08_honbun.pdf

FY2018 Policy Evaluation Report (preliminary project evaluation)

Responsible Department Name: Defense Acquisition Agency Project Management Department Business Supervisor (Naval Ships)

Evaluation implementation period: July 2018 to August 2018

1 business name

Research prototype of high-efficiency power storage and supply system for submarines

2 Positioning in the policy system

(1) Name of measure

Promotion of research and development

(2) Overview of measures

Given the severe financial situation, prioritize the implementation of R&D that meets the operational needs of the Self-Defense Forces.

In order to ensure that, when starting R&D, ensure consistency with the priority order of defense buildup.

It can also respond to new threats and ensure technological superiority in areas of strategic importance.

Trends in science and technology, changes in combat modalities, cost-effectiveness, possibility of international joint research and development, etc.

We will promote research and development based on a medium- to long-term perspective, while also taking into account From the perspective of security, technology.

Always keep abreast of trends in science and technology, such as development-related information, and combine the strengths of industry, academia, and government.

A technology management system to prevent the outflow of advanced technology, etc.

Strengthen your ability. In addition, through enhanced cooperation with universities and research institutes, civil

In addition to striving to actively utilize technology (dual-use technology),

We plan to expand.

(3) Goals to be achieved

Prioritize research and development that meets the operational needs of the Self-Defense Forces. In addition, new threats the latest scientific and technological developments to ensure technological superiority in areas of strategic importance.

Medium- to long-term, while taking into account the direction of warfare, changes in combat modalities, cost-effectiveness, and the possibility of international joint research and development.

We will promote research and development based on diverse perspectives.

3.  Business overview, etc.

(1) Business overview

Future submarines will have the ability to perform missions in a more stringent security environment and a higher level of detection and defense.

Sustainability and mobility are required, and it is necessary to study how to meet these requirements.

In this project, in order to improve the submarine's underwater sustainability and to control the size of the submarine, an electric power storage system will be installed.

Prototype system and power supply system, miniaturize main storage battery for submarine, increase energy.

This is to establish technology for downsizing and improving the efficiency of equipment such as power converters.

(2) Required expenses

Approximately 4.4 billion yen [US$30.7 millions] (approximate amount requested in 2019. Including the amount to be borne in later years. Total cost of research prototypes: approx. 8.2 billion yen [US$57.3 million]

(3) Timing of project implementation

A research prototype will be implemented from FY2019 to FY2022. In addition, the results of this project and related precedents.

Combined with the results of the project, an in-house test simulating the state of installation on a submarine will be conducted in FY2023.

Implement and verify the results. (Experimental research expenses for in-house tests will be recorded separately.)

[Japanese Imperial] Years 28 29 30 31 32 33 34 35 36

Actual project (research prototype)

Done

Of which, related preceding business In-house test

Capacity

Research implementation schedule

4 Aim of evaluation

Conducted a preliminary evaluation of research to be newly implemented  from FY2019 among the research and development projects thing. Evaluation was made from the viewpoint of necessity, efficiency and effectiveness of this research.

5 Policy evaluation results

(1) Necessity

A Reason for the Ministry of Defense to implement the project

This project aims to improve the efficiency and energy of the power storage and supply system installed on submarines.

This is a research and verification [program] that considers the feasibility and safety of the submarine as a whole is essential. 

Therefore, since there is no research institute other than the Ministry of Defense that conducts the research, the Ministry of Defense is independent.

You have to do it yourself.

B Necessity of implementation from the relevant fiscal year

The results of this project are related to the basics of submarines, such as the size of the hull and the amount of power supplied.

Maritime Self-Defense Force's total ship (entire submarine including on-board equipment) study.

This is the premise of off-study (examination for reconciling contradictory performance). 

In order to carry out these studies with high precision without rework, it is necessary to obtain results within FY2023.

However, since it takes 5 years including the research prototype and the in-house test, FY 2019.

C. Reasons for not relying on existing organizations, equipment, etc.

In other countries, Germany is developing lithium-ion batteries for submarines.

The power storage technology and power supply technology are highly sensitive, including the other countries. 

In addition, [the aim of minimising] the enlargement of the hull and improving underwater sustainability.

Since it is essential to connect with the study of the ship, it is expected that the equipment of other countries will be introduced as it is.

D. Status of comparative examination with alternative means

We examined the possibility of improving and improving the existing equipment, the current power storage and supply system.

In the system, the high-density installation of the main storage battery, miniaturization and high efficiency of the entire power supply circuit could not be implemented.

Elucidation and investigation of technical issues such as new design and safety of the entire power supply system equipment, power storage / supply characteristics, etc.

Since proof is required, this research and development is necessary instead of light improvements and improvements.

(2) Efficiency

Among the components of the submarine's power storage and supply system, the minimum necessary for clarifying technical issues

By making a prototype of a limited combination, we aim to shorten the research period and reduce the cost.

(3) Effectiveness

A. Effects to be obtained

(a) Main storage battery high capacity technology

High-precision measurement technology for voltage, temperature, etc., and charging technology that can demonstrate the capabilities of submarine main storage batteries.

While establishing discharge management technology, we will apply the latest storage material technology to increase the capacity of the main storage battery.

(b) High-density outfitting technology for main storage battery and power supply system equipment.

Confirm high-density outfitting technology for submarines, cooling technology for high-density outfitting, fire extinguishing technology, etc.

(c) High-efficiency power conversion, power saving technology

High-efficiency power supply technology and high-efficiency power that meet the load characteristics, safety, and environmental resistance of submarines.

Establish conversion technology and protection device technology.

B How to grasp the effect.

In this project, we will design and manufacture a prototype and test each component.

Confirm the overall performance of the system by conducting in-house tests simulating the state of installation on a watership.

At the same time, we will verify whether technological superiority and safety are ensured.

In the design and manufacture of prototypes, the technical validity of the design shall be

Conduct business while confirming In addition, are the "General Guidelines for National Research and Development Evaluation" (decided by the Prime Minister in 2016), multiple stages of research and development before and during the project.

We are planning to conduct evaluations to ensure appropriate project implementation.

(4) Cost and effect

In implementing this project, Japan's excellent consumer technology such as battery technology and power conversion element technology should be used to test and evaluate the feasibility and safety of the ship as a whole for installation on a submarine.

Targets are narrowed down to reduce costs. In addition, we will gradually introduce these consumer technologies that are developing rapidly.

Considering that it is easy to replace the main storage battery, the design makes it easy to replace the battery.

Aim to reduce cycle costs.

While making these efforts, in addition to the establishment of various technologies mentioned in the previous issue, the superiority of these technologies is expected to be secured, it is judged appropriate to start this project.

6 Timing of ex-post verification

Regarding technical verification, the Acquisition, Technology and Logistics Agency will provide technical verification at the intermediate stage. In addition, after verifying the progress of this project in cooperation with the administrative project review, will carry out rational policy evaluation.

7 Comprehensive evaluation

By implementing this project, it is expected that the various technologies mentioned in item 5, item 3 will be established. 

These results will be verified through in-house tests simulating installation on a submarine. If the verification results are obtained, Japan will develop world-leading high-capacity storage materials and high-efficiency.

Establishment of basic technology for applying power conversion devices to submarines is expected.

These are extremely important achievements in securing technological superiority in areas of strategic importance.

Ultimately, this will lead to the establishment of a foundation for demonstrating the capability of the defense force, which is the policy goal.

8 Opinions of Experts

- If the results of this research can be used in the private sector, we would like you to consider the transfer of technology.

・ A little more additional explanation about the performance improvement of high efficiency and miniaturization of the power supply system.

- I would like you to consider conducting post-evaluation after the completion of research and development for which pre-evaluation was conducted.

9 Direction of reflection in policies, etc.

Based on the comprehensive evaluation, a budget request for FY2019 will be implemented.

10 Other reference information

Research summary (Attachment)

[4]  Example of success - commissioning ceremony for new sub JS Toryu March 24, 2021 https://www.mod.go.jp/en/article/2021/03/edb7a684dc1b61b33d4462cf7d5fde9e7866eb40.html“...Defense Minister Nakayama attended the commission ceremony for the new submarine JS Toryu, the 12th submarine of “Soryu” type and instructed to the crew.

The newer “Soryu” type submarine that were planned after FY2015 [equipped with]   lithium batteries that are superior in underwater durability. “Toryu” is to be deployed at the 6th Submarine Division and enhances our information gathering, warning and surveillance capability .”

[5]  Submarine Matters' Oyashio-Soryu-Taigei TABLE as at September 12, 2022.