Honda Hybrids and the heat

[Right Lane Cruiser]

Honda does confirm that the batteries can be affected by hot *or* cold temperature extremes.

KVOA - September 27, 2010

Is this just another case of an owner not adjusting to new battery management behavior, or is there a real issue here? --Ed.

Unlike the heat of summer, hybrid cars aren't going away anytime soon.

The popular 'rides' get great gas mileage, and are good for the environment. But an Arizona man claims the summer heat did a number on his hybrid's batteries.

Michael Sifford recently brought his car to a Honda dealer after the engine light came on. Technicians performed a recall update on what's called the i-m-a, or 'integrated motor assist.' That's the hybrid computer that controls the engine and the battery consumption. Sifford said his hybrid hasn't been the same since.

Sifford said Honda's regional rep came to the dealership, and told him that a core battery temperature of 130 degrees would shut the i-m-a system off, thus, the car would be underpowered.

News-4 Tucson spoke by phone with a Honda Representative, who says they're not aware of any... [Read More]

[herm]

I wonder if the owner is a hypermiler?, in any case, 130°F is too high a temperature.

How come Toyota has not had all these batteries issues?

[Right Lane Cruiser]

Toyota moved to a prismatic cell for the (now iconic) second generation Prius -- these are much more easily managed when it comes to thermal properties than the cylindrical cells used in Honda hybrids. Licensing issues prevent Honda from using the newer and better prismatic cells (because Toyota has a partnership with Panasonic and that company won't sell the batteries to Honda).

The first generation Prius (the one with a trunk instead of a hatch) had the cylindrical cells and those do indeed have similar battery issues to the ones experienced by Honda Hybrids.

[msantos]

Sean is absolutely correct.

That is why Honda now has Yuasa (of Kyoto, Japan, a reliable battery manufacturer) as a partner that will ensure not only the best of breed battery tech but also the quality yields it needs for mass production goals.

Cheers;

MSantos

[Mendel Leisk]

That is why Honda now has Yuasa (of Kyoto, Japan, a reliable battery manufacturer) as a partner that will ensure...

It seems to me the honourable course for Honda would be to produce some of these best-of-breed batteries to the HCHII spec, and replace batteries for any HCHII that are proven to be deteriorated, free of charge.

[Right Lane Cruiser]

Mendel, I'm not sure how possible this would be since the new batteries are Lithium instead of NiMH based.

[Mendel Leisk]

Because they have different performance characteristics? I can see that.

What bothers me is Honda telling the reporters they are getting next to no complaints, and so on. This smells, bad.

[msantos]

While it would be technically possible to easily design and produce an updated BCM plus the slight algorithm changes it would entail, bigger problems would remain:

- The re-engineering cost of the retrofit destined for an end-of-life model (HCH-II) is certainly not trivial

- The operational/environmental constraints imposed by the Li-Ion chemistry. In other words, there would have to be some physical design changes made to the IPU layout and support systems and related components to accommodate a Li-Ion assembly as this chemistry is usually far less tolerant of environmental irregularities than the Ni-MH assemblies made for automotive use.

- The other thing to remember is that we have to take into account the behavior of the current HCH-II packs and the perception of failure that is the cause of this "BatteryGate" fiasco versus the "actual truth". And from the reports we've been seeing, the truth is that even though Honda easily replaced quite a few thousand with no questions asked, very few of those batteries that were subsequently inspected, were actually failed beyond recovery. That is why nowadays, it is very hard for anyone to expect a prompt and easy battery pack replacement as some did in the firs three years of the models life cycle. The rule is quite simple now: Have the software installed first and then we'll discuss later after the software had its chance to do its work.

Cheers;


MSantos

[Right Lane Cruiser]

My impression was that Li-Ion batteries that do not have a cobalt component are actually more tolerant of environmental irregularities than NiMH chemistry?

[msantos]

Originally Posted by Right Lane Cruiser

My impression was that Li-Ion batteries that do not have a cobalt component are actually more tolerant of environmental irregularities than NiMH chemistry?

Hi Sean;

You are correct in that of the three most common cathodic materials, the Cobalt Oxide type is generally perceived as the most stable.

Still, as of my last check run-away thermals (among other operational limits) are still much more common and severe in the Li-ION than on its older counterpart (NiMH). The only moderating design attribute that greatly reduces the bigger detriments of the Li-ION tech depends on designers choices when they pick from a collection of materials to produce their own Li-ION "cocktail". Sadly this almost always means an implied reduction of capacity (energy density).

As far as I know, the race to develop the best Li-ION cocktail is still on and much work remains to be done on this front but the NiMH remains the most solid chemistry. Too bad the Post-Ovonic legacy prevented this tech from shining when it had a chance.

Cheers;

MSantos