Following last week's articles (here, here and here) Anonymous continues representation of electricity discharge and generation using combinations of Lithium-ion Batteries (LIBs), Lead-acid Batteries (LABs) and Air Independent Propulsion (AIP). An extra variable is use of Diesels on full or half power.
Tables 1 and 2 present extra comparative information.
Figure 4
Anonymous
Tables 1 and 2 present extra comparative information.
Figure 4 (below) is the output of diesel generators for model submarines:
Diesels in LIBs-sub operate once every two-days (no operation on Day 2) using diesel on full power.
(a) LIBs + new diesel generator (GE), Power of new Diesel increases to 125% compare to old Diesel. This is noting LIBs require (or benefit from) more powerful Diesels.
(b) LIBs + full power Diesel,
C-rate of LABs is 0.2C. Output of each Diesel is 2 and 4M in half and full power, respectively.
(c) LABs + half power Diesel + AIP. In AIP operation. LABs are not discharged.
(d) LABs + half power Diesel, Operation cycle of LABs-sub is once a day.
Grey represents no generation using Diesel;
Green represents Diesel generation;
Purple represents AIP generation;
Lower axis Figure 4 represents electricity discharge and generation according to which team of the 3-watch crew roster are on duty. Where:
- Red represents team 1;
- Yellow represents team 2;
- Blue represents team 3;
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4 | Snorkeling/Diesel | (a) LIBs+new Diesel (day 1 of 2 days) | ||||||||||||||||||||||
2 | Discharge | Discharge to day 3, 20:00 | ||||||||||||||||||||||
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4 | (b) LIBs +full power Diesel (day 1 of 2 days) | |||||||||||||||||||||||
Snorkeling/Diesel | ||||||||||||||||||||||||
2 | Discharge | Discharge to day 3, 20:00 | ||||||||||||||||||||||
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4 | (c) LABs + half power Diesel + AIP (every day) | |||||||||||||||||||||||
2 | Discharge | Snorkeling/Diesel | Discharge | |||||||||||||||||||||
AIP mode (240kW) | ||||||||||||||||||||||||
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4 | (d)LABs + half power Diesel (every day) | |||||||||||||||||||||||
2 | Discharge | Snorkeling/Diesel | Discharge | Snorkeling /Diesel | Discharge | |||||||||||||||||||
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time | 19 | 20 | 21 | 22 | 23 | 00 | 01 | 02 | 03 | 04 | 05 | 06 | ||||||||||||
Table 1 - Performances of models
Model | Indiscretion ratio, IR [1] % | Submerge at max speed [2] h | Capacity of battery MW | Output of Diesel [3] MW | Rotation of Diesel rpm | C-rate | |
Current status | Limit [4] | ||||||
LIBs + new Diesel | 5.2 | 10 | 50 | 5 | 1200 | 0.1 | 1 |
LIBs + full power Diesel | 6.3 | 10 | 50 | 4 | 1200 | 0.08 | 1 |
LABs + half power Diesel AIP | 8.3 | 1 | 10 | 2 | 600 | 0.2 | 0.4 |
LABs + half power Diesel | 12.5 | 1 | 10 | 2 | 600 | 0.2 | 0.4 |
[1] LIBs, IR=operation time (green)/48 x 100; LABs, IR= green/24 x100.
[2] Max speed is 18 knots; Energy consumptions are 4.5 and 40.5MW for LABs and LIBs,
respectively.
[3] Data is total output of 2 Diesels. Model sub is equipped with 2 Diesels operating
simultaneously.
[4] C-rate of LIBs is general data. Value of LABs is for high speed charge/discharge rate.
Table 2 - Important factors
Term | Discussion | LAB | LIB |
C-rate | As C-rate of LAB is small (0.1C, 0.2C) and capacity is low, C-rate dominates charge/discharge rate. Higher C-rate (0.4, 0.5C) is possible, but, it shortens life of LAB. Half power of Diesel can satisfy C-rate of 0.2C. | Dominative | - |
Output of Diesel | As C-rate of LIB is large (0.5C, 1C) and capacity is high, output of Diesel dominates charge/discharge rate. To get low indiscretion ratio, output of Diesel needs to be increased. In Fig.4 (a), C-rate is only 0.1C. Higher rotation of Diesel or increase of Diesels is possible measure, but it increases noise or vibration. | - | Dominative |
Snorkel capacity | To realize high performance of LIBs, improvement of Diesel will be conducted within framework of snorkel system capacity to provide air (oxygen) to Diesel. To achieve C-rate of 1 for LIBs, Diesel requires 10 times larger amount of oxygen from snorkel system. As increasing the flow rate ten times is difficult (max. two- or three-fold increases?), C-rate of 1 is difficult to achieve (max 02-0.3?). | - | Dominative |
Propulsion motor | To achieve high speed performance by LIBs, improvement of propulsion motor is required. | - | Important |
Conclusion | To realize high performance submarine equipped with LIBs, comprehensive improvement of power system including Diesel, snorkel system and propulsion motors as well as development of LIBs are required. Also, improvement and establishment of peripheral technologies including safety system and further reduction of noise/vibration are needed. | ||