Li-Ion King: New Ford Test for Hybrid Vehicle Batteries Simulates 10 Years of Use in 10 Months’ Time

Yea, they improved the cooling. The chemistry, cells and modules are exactly the same. What's your point?

Not sure where you are getting the misinformation from. Per bloomberg article, straight from Toyota engineer, "durability, stability and safety are assured" in the 3 years Li-ion battery test from 2006-2009. “We now know that a lithium-ion battery can work; that’s not really the question,” he said.

Both Toyota and Ford hybrids are very similar but the ways they use the battery are different. On the highway (below 62 mph), Ford hybrid's gas engine need to produce excessive power to be efficient. So it charges the battery and shuts the gas engine down later and repeat. That puts extra strain on the battery. Toyota engineers the gas engine so it does not have excessive power.

My point is, the life of the battery will vary depending on how it is used.

 

Do you know what their definition of "end of life"? For Toyota hybrids, 80% of the original capacity is the end of life.

 

The fix was inter-connectivity between modules. I am not aware of changes in the SOC control and the power algorithms.

Do you have any source to back it up?

I know the switch from cylindrical to prismatic improved the heat transfer, hence improving the power output. Another improvement was made when the module casing material was switched from plastic to metal. That further improved power output but increased the weight. Those are only used for larger hybrids (Camry and Highlander) that require more power.

 

Easiest way to see the external change is the specification - 27 kw versus 25 kw in gen III versus gen II. They decided they could run higher power. They also changed SOC that EV could run, and actually gave a button to folks in NA. The point is simply that they can test much of this stuff in the lab. They did not need to wait 10 years and run mules for each of the changes. There is no reason they should have to for lithium.

Yep only minor improvements since 2003.

 

The 80% comes from EVs not Hybrids. A Prius HV battery "end of life" is when the computer says that the HV battery can no longer be counted on to reliably start the ICE if used normally and the ECU cuts down the use of the battery for "non-essential" functions. The Battery then will usually fail completely in a few weeks.

JeffD

 

I was referring to the original test Toyota did with NiMH.

 

I never saw an 80% test for hybrids, can you refer me to it? Since they only use 40% SOC (40%-80%), they would have to take the batteries out of the cars and test them on the bench. I have only read about toyota doing such tests recently with lithium not nimh. I am not saying they don't do it, but I would be surprised at a 80% 10 year aging test on nimh. They do get the batteries back when they fail, so they can test the failing cells.

I would expect as the batteries age the bms would change the SOC parameters to operate well with minor degradation. Maybe bob wilson csn chirp in, since he knows about replacing bad cells in the older battery design.

 

Here is the SAE article with the graph at the end (Figure 8). It is a distance (km, not mile) vs. internal resistance graph.

I thought it was km vs capacity loss graph. I guess I recalled it incorrectly. Let me continue to look for where I got the 80% from.

This paper also has some information about the battery but it covers all the improvements from Gen1 to Gen2.

 

I couldn't follow the link, sorry, can you confirm?

 

I can open it fine. If it doesn't work, you can try here.