Naval Ship & Submarine Propulsion Systems

John Fedup

The Bunker Group
Yes, you would definitely need another power source for the transit portion. However, these batteries combined with diesels (or perhaps fuel cells) would definitely allow for under-ice sovereignty patrols. And when I re-read the article it was "more than 30 days at 8 knots".
Thirty days at 8 knots or 60 at 5 knots, whatever, the system is theoretical at this point.
 

Calculus

Well-Known Member
Thirty days at 8 knots or 60 at 5 knots, whatever, the system is theoretical at this point.
Pretty much everything discussed in this thread is theoretical. But we've seen similar estimates made for the Japanese subs (see infographic below), so I think it's pretty safe to say that those kinds of ranges are more than just theoretical.

Image courtesy of SSK Soryu Class Submarines
 

Attachments

John Fedup

The Bunker Group
Pretty much everything discussed in this thread is theoretical. But we've seen similar estimates made for the Japanese subs (see infographic below), so I think it's pretty safe to say that those kinds of ranges are more than just theoretical.

Image courtesy of SSK Soryu Class Submarines
Yes, the one way 3000 nm at 8 knots then return likely is more than theoretical but is it sufficient for patrols likely starting from Halifax?
 

MARKMILES77

Active Member
Lead acid, at least for the majority of the propulsion. TBH I don't see that changing in the short term.

Even the Lithium subs and designs that exist now, its more about lithium replacing AIP than the entire lead acid battery. If you replace the entire battery with lithium, you might as well throw away your diesels, because you will never be able to charge that battery with the diesels on board. Its more a balance of indiscretion rate and mission. You have also made your conventional submarine 20 times more expensive.

Where as if you look at say enough lithium for several hours of operation, being able to recharge that with a doable indiscretion. Its a small additional cost, you get significant benefit, you maximize lithium advantage, fast charging, fast discharging, heavy cycling, no out gassing etc, while maximizing lead acids cheap bulk storage. Your lead acid battery stays in better condition, you have more operational flexibility, etc. Minimal extra cost.

Fuel cells only fit some mission profiles. For Australia, things with liquid oxygen make no sense. By the time we transit through hot tropical waters, for weeks, there will be nothing left, just from outgasing heating. It would take more to keep it liquid than to propel the submarine. The Japanese made it work because they pretty much on patrol from the time the slip out of their harbor, and they dive deep into the cold and stay there, moving a few knots. But even then, Lithium has provided a better advantage.
The new battery chemistry that is most likely next for Australian subs (possibly including Collins) is not Li Ion but Nickel Zinc.
It does not have the ultimate energy density of Li Ion batteries but is superior in pretty much every other way including the most important, safety.

Much cheaper
No need for a complete redesign of the subs electrical systems as there is for Li Ion. Very close to being a drop in replacement for Lead acid.
Zero risk of thermal runaway or fire. unlike Li Ion
No off gasing of Hydrogen unlike lead acid
Long Life
No maintenance
Has a recharging profile which is ideal for submarines. Optimal charging is done in short rapid bursts. They don't like trickle charging.
Energy density approximately 2.5 X lead acid BUT doesn't mind being discharged to zero so effectively has 4 to 5 times the energy density.
AND is being developed for submarine use in Australia by PMB who make the Collins Lead Acid Batteries.
Here is a screen shot from their website:Screen Shot 2020-09-17 at 7.48.13 pm.png
 
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MARKMILES77

Active Member
Have no idea who PMB are partnering with with on their Nickel Zinc Sub batteries but "Zinc Five" must be the favourites as they are producing Nickel Zinc batteries currently for many applications. ZincFive
Screen Shot 2020-09-18 at 8.52.29 am.png
 

aussienscale

The Bunker Group
Verified Defense Pro
Another big thing some seem to forget or just simply do not take into account and ignore is the thermal efficiency of the different types of batteries, makes a big difference in charging times, capacity and discharge rates.

For a submarine that operates in a given environment with fairly consistent sea temps can be a relatively easy thing to model energy usage, but when you have a Diesel Electric submarine using battery technology operating in a blue ocean capacity such as Australia does, from the frigid waters of the southern oceans to warm tropical and everything in between, and in the one patrol, it adds so much more complexity to the equation !

So to simply say we should have Li-on batteries because of their capacity, discharge rates, etc ignores so much more in actual operational reality and requirements, along with everything else that has been said.

PMB are a great company and do some fantastic work, their knowledge and research is top notch and very highly regarded

Cheers
 

StingrayOZ

Super Moderator
Staff member
The new battery chemistry that is most likely next for Australian subs (possibly including Collins) is not Li Ion but Nickel Zinc.
It does not have the ultimate energy density of Li Ion batteries but is superior in pretty much every other way including the most important, safety.

Much cheaper
No need for a complete redesign of the subs electrical systems as there is for Li Ion. Very close to being a drop in replacement for Lead acid.
Zero risk of thermal runaway or fire. unlike Li Ion
No off gasing of Hydrogen unlike lead acid
Long Life
No maintenance
Has a recharging profile which is ideal for submarines. Optimal charging is done in short rapid bursts. They don't like trickle charging.
Energy density approximately 2.5 X lead acid BUT doesn't mind being discharged to zero so effectively has 4 to 5 times the energy density.
AND is being developed for submarine use in Australia by PMB who make the Collins Lead Acid Batteries.
Here is a screen shot from their website:View attachment 47747
I think something like or Nickel zinc would be a good fit for an Australian submarine. I don't think Nickel Zinc are quite exactly a drop in replacement, but a much closer to being one in terms of safety and would require less specific design requirements to be considered. Its one of the reason why I don't think we should be too concerned for a submarine that is still being designed around the specifications/requirements of a lead acid battery. That does not mean that lead acid is the only battery technology available to be fitted, and most of the submarine technologies are using lead acid as the key requirements for their solution. There are several battery technologies that would be quite suitable that are cheaper and lower risk than lithium (such as NiZn and NiMH). These would still offer a huge upgrade over traditional lead acid. There are also several advanced lead acid batteries that close the gap between lead acid and more modern chemistries.

Given how large the Attack class will be, displacing over 5000 tons of a particularly low drag design, even a fairly conventional battery will result in very significant performance from the sheer size of it. Quick Charging such a battery will be interesting.
 

Calculus

Well-Known Member
Yes, the one way 3000 nm at 8 knots then return likely is more than theoretical but is it sufficient for patrols likely starting from Halifax?
No, not on batteries alone. You would use your diesels to get to the patrol area, and the batteries for the under-ice portion.
 
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