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GS Yuasa develops 12V Li-ion battery for start/stop applications

Engineers at GS Yuasa in Japan have developed a 12V lithium-ion battery targeting the start/stop systems market. The external configuration of the Li-ion battery is compatible with DIN LN5 12V lead-acid batteries, and the operational voltage range is almost the same as the lead-acid battery. Therefore, the new lithium-ion battery can physically replace a LN5 lead-acid battery in a vehicle.

Inner structure of 019SLIB type 12 V lithium-ion battery. Click to enlarge.

The new lithium-ion battery uses a Lithium Iron Phosphate / Graphite combination and offers advantages in comparison with the traditional lead-acid battery in terms of light weight, high power and long life.

The battery comprises four 69 Ah cells, a relay assembly, a current sensor and a battery management unit which has a LIN (Local Interconnect network) interface with the vehicle ECU (Electronic control unit).

Although the Li-ion battery can be physically dropped-in, the LIN interface protocol between the vehicle ECU and the battery management unit should be modified, and the control of the alternator should be optimized for the lithium-ion battery, the developers noted.




I thought 48 volt was the big coming thing and had imagined that lithium battery makers would skip straight to it.


Apparently the 48volt batteries incorporate a conventional lead acid 12 volt at present:

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They "forget to mention" this battery is inferior to lead acid batteries in very cold weather and that it cost at least 3 times as much as lead acid.

Davemart 48 V is in addition to a 12V system not a replacement. Cars will always have dozens of subsystems that require 12V. Future cars will have many electric systems 600V for the engine, 120/240V for ordinary appliances, 48V for efficient servo steering and AC (or start stop in combustion vehicles) and 12V for the electric windows, cabin light, hifi etc.


My guess is that you have never been a photographer.
The battery of choice there are lithium, as some chemistries are very tolerant of the cold.

And here is a comparison of lead acid versus lithium, see graph 8 for low temperature performance:

This is for storage purposes, which in this context simply ignores the extra weight of lead-acid batteries

You are quite correct about the need for 12 volt.
What I had not realised, not being an EE, was that a separate 12 volt battery would be required, not simply stepping down the voltage.

I corrected my oversight in my second post however.


Actually, there is a push to move 12V subsytems to 48V. There are many advantages to this (more efficient, smaller, lighter wiring, etc). However, it is very early and there is so much inertia to the older 12V systems and their high volume manufacturing that it will be a long, long time before the 48V will be used in most cars.

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