Li-ion traction battery life?

Although a year ago, could you elaborate on the symptoms of the NIMH battery failing? Our 2006 just turned 189K today and I perceive strange things going on. The vent hole in the back seat was producing a whirring sound earlier and the batt icon floats between several green bars to pink to very few blue bars...

thoughts?

 

I think you should have started a new thread in the Gen 2 forum. You have neither a Gen 4 nor a Lithium Ion battery. You are extremely off topic.

 

Is the "offering" of NiMH vs Lithium Ion batteries related to ambient temps? For example, we know the NiMH has a shorter life in places that are very hot (don't we?). I have heard the lithium ion would have problems with very cold temps. My suspicion is this is why the lithium ion is rare in Canada, where we get the NiMH battery on most models. And the Prime is not yet available across Canada. Or is it production based (not enough to go around)?

 

In the US before Gen 4 there was only Lithium Ion in the Plugin Prius. Canada tends to follow the US quite closely. For Gen 4, the trims one and two have NiMH and two Eco and above have Lithium Ion as does the Prime. Gen 4 in Canada also has a mix of battery types, from what I remember.
So, it is rare because there are not many Gen 4 Prii on the road.

 

The Prius v (Prius +) in Japan and Europe had a lithium ion battery starting in 2012. Wonder how thoes are holding up after 5 years now

 

All sound like symptoms of a battery struggling.

But the Prolong battery equipment can help:

Prolong Battery Systems. Extending the life of your hybrid. – Hybrid Automotive

Hope that helps.

 

"Recall that the Li-Ion is meant to reduce weight rather than increase performance."
Hello,
I'm no expert on batteries, but per the Toyota brochure lithium battery has 207.2 volts, nickel battery has 201.6 volts. Of course other variables can change performance, but perhaps someone with more knowledge might know if that difference in voltage is significant.
Thanks, Peace.

 

I would suspect the voltage is regulated so the same motors etc. can be used. @Elektroingenieur may know more.

 

First, you are quoting the nominal voltages and the actual voltages of both are noticeably higher (224 volts for NiMh when fully charged). Some performance issues are:

• How much energy can each battery store/supply - Energy is approximately proportional to Amp-hour capacity (6.5 amp-hours rated capacity in NiMh modules) times voltage.
  • I know that the NiMh batteries in Prii are only operated between 40% and 80% capacity to extend their life
  • Nominal NiMh capacity is 201.6*6.5 = 1.3 Kwatt-hours
  • Usable NiMh capacity is about 500 watt-hours
• How much power can each battery deliver /accept for short periods - Power is approximately instantaneous current times voltage
  • The NiMh batteries are limited to 130 amp currents (100 amps pre 2006) to avoid over heating.

So your question is somewhat more complex than simply looking at the nominal voltages and I, for one, have to do a bit more research to find out the limitations of the Lithium batteries in my 2016 Prius. What I know so far is:

• 56 cells : 3.7V
• 28 cells/stack : 103.6V
• 2 stacks/pack : 207.2V
• 3.6 Ah

total 745.92 Wh, but as in the NiMh probably used over a limited range of capacity and will have about the same usable capacity.

JeffD

 

Thanks for the valuable info. As I suspected there are many variables involved
Just based on what we know about the 2 battery choices in the Gen4, which would you say is "better" in terms of things like performance, efficiency and long life.
If you or any others do reply, thank you in advance.
Peace

 

Toyota must feel that Lithium is an improvement overall or they wouldn't have switched. As far as efficiency, Lithium is smaller and lighter as stated above which helps. It also loses less energy in the charge/discharge cycle. I'll wait another 8 years to see how reliability compares as NiMh did quite well on average.

JeffD

 

These are just the nominal voltage.

The actual terminal voltage on the NiMH pack varies from ~170-270v depending upon SOC and current flow. I don't know what the Li-Ion range is but it is probably similar.

The boost converter from the battery up to the inverter rail takes care of those voltage variations so they have an insignificant effect.

Actually in the SAE paper (2016-01-1207) they give the Li-Ion pack voltage as 201.6v not 207.2v. This is equivalent to a 3.6v per cell nominal voltage rather than 3.7v.

kevin

 

Thank you both for more valuable information, the topic of battery performance just keeps getting more interesting, at least to me.

 

You might not need to wait 8 years. The Plugin Prius in the US and some models overseas used a Li-Ion battery too.
In my personal case, I wanted a spare tire and did not think the price premium for a trim 3 over a trim 3 was worth the extra money.
Toyota seems to make battery improvements in each generation. I understand the Gen 4 NiMH battery uses a higher quality nickel alloy,

 

This is an old thread - and while it was possibly a bit cynical, my opinion last year in POST #19 still could be relevant. The reality is that nobody is certain as to why TOYOTA offered NiMH only on some markets, and limited Li-ion on other markets. Supply? Longevity? We don't know.

NiMH, being older, is more mature technology - but possibly not going to be advancing too much more. Li-ion is a younger technology, potentially still improving over several more generations.

Re longevity of existing Li-ion vehicles, the PRIUS v also has a Li-ion battery, and if you were to buy a PlugIn Hybrid from BMW, Merc, AUDI, VOLVO, Mitsubishi, Nissan etc etc, it will be Li-ion.

Plus - most pure EVs use Li-ion - (Mitsubishi i-MiEVs, Hyundai Ioniqs, Kia Souls, Nissan Leaves (no it didn't leave), Renault Zoes and Teslas etc).

 

Toyota may have been cautious, especially after the news, in the US at least, of (Dell?) laptops with Li-Ion batteries catching fire. They wanted to be extra careful, IMHO.

 

Sony laptops used to catch fire, Boeing Dreamliner batteries had some issues, and, lest we forget, there was the Samsung Galaxy "Firestarter" Note 7.

 

You forgot the Dells.

Dell laptop explodes again and again and again - CNET

Fire Hazard Prompts Gigantic Dell Laptop Battery Recall | PCWorld

 

To get 10+ years cycle life Toyota is under charging the cells (reduced SOC). This also reduces the chance of internal short circuit.