NiMH Battery Internals

Discussion in 'Prius c Technical Discussion' started by Lakshman Fernando, Apr 2, 2021.

  1. Lakshman Fernando

    Lakshman Fernando New Member

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    Hi do anyone know what chemical used for refill Nimh battery from Prius
    Please give idea what liquid
     
  2. Lakshman Fernando

    Lakshman Fernando New Member

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    And where can I buy it
     
  3. Elektroingenieur

    Elektroingenieur Senior Member

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    The HV battery modules are sealed, and as far as I know, it’s not practicable to replenish the NiMH electrolyte, nor is it available for sale. As Toyota warns in the Emergency Response Guide (PDF), “The NiMH battery electrolyte is a caustic alkaline (pH 13.5) that is damaging to human tissues.”

    The HV battery isn’t like a traditional lead-acid battery, to which one might routinely add water or acid. Instead, in Toyota’s service strategy, when the HV battery reaches the end of its useful life, it’s removed for recycling and replaced with a new one. Some people try to rebuild HV batteries by replacing defective modules, but this generally isn’t considered a reliable, long-term repair.
     
  4. ozmatt

    ozmatt Active Member

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    It's just koh, however only the water depletes so you can just inject good water.. there is a thread on here somewhere about module rehydrating check that out if you can find it, it covers mostly everything you are curious about.

    I tried my hand at this a few years back, while it definitely improves capacity and lowers resistance i struggled to reseal the modules to my satisfaction, others claim they were successful.

    Posted via the PriusChat mobile app.
     
  5. sam spade 2

    sam spade 2 Senior Member

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    You probably can't.
    And even if you could, it likely would be a waste of time.
    The plates get contaminated too as the fluid "wears out".
     
  6. Prodigyplace

    Prodigyplace Senior Member

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    Some people here tried rehydrating Gen 1 Prius modules but I have not heard of people doing that recently.
     
  7. ChapmanF

    ChapmanF Senior Member

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    I think the most recent reports I remember seeing were Albert Barbuto's from about a year ago.

    Was adding only distilled water, as that's the only component of the electrolyte said to leave (by offgassing through the vent valves, that is; if a module gets leaky and actual electrolyte squishes out, surely that's another story).
     
  8. Jameson Roob

    Jameson Roob New Member

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    Most probably HEV, emerging EVs, and fuel cell EVs used for refill Nimh battery.
     
  9. C Wagner

    C Wagner Member

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    It's not practical for a DIY person (or commercial rebuilder) to fix the NIMH internal cells within a module, AFAIK.

    Did you see the Wiki section at the top of the priuschat screen? Check there for the Wiki I wrote on How To/ "Maintenance" under repairing the HV battery. Here's the link: Prius High Voltage Battery Reconditioning | PriusChat
     
  10. anas abu kaff

    anas abu kaff Junior Member

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  11. C Wagner

    C Wagner Member

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    I didn't watch the whole upgrade video, but does it include a redesign of the charging system? Li-Ion modules and NiMH modules require different charging, discharge, usage systems. NiMH is used in cold climates with better results than Lithium I believe too.
     
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  12. Pri3C

    Pri3C Member

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    The install just replaces the NiMH blocks with lithium blocks, same computer and sensors. If you have questions about how this works you should contact them directly, or post here if the question hasn’t been answered.
     
    #12 Pri3C, May 14, 2021
    Last edited: May 14, 2021
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  13. Prodigyplace

    Prodigyplace Senior Member

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    Lithium upgrade is off-topic in an NiMH thread anyway.
     
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  14. Pri3C

    Pri3C Member

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    Which is why I directed them to the appropriate thread where their question might be answered.
     
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  15. tracy ing

    tracy ing Active Member

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    I dont know why people cant just answer a question here

    Where is starbucks ?
    Why do you want starbucks, it is overpriced and their is a 711 closer, anyhow, why buy coffee thats already made, you can surely make it cheaper at home then put it in a thermos and bring it with you safing lots of money

    HOLY CRAP JUST ANSWER PEOPLE, the starbucks guy might be meeting someone or needing wifi, just tell him where it is for gods sake

    It is BY WEIGHT 30% KOH aka Potassium Hydroxide widely available I get mine "food grade " DO NOT EAT IT from Amazon
    The other 70% BY WEIGHT is DE-IONIZED WATER

    Yes, it mostly vents WATER however if you put only water in you will dilute the existing KOH as some of it has migrated into the anode cathode due to charge over temp over pressure followed by VENTING. So some KOH is likely going to be needed not just water.

    Is there a way to get it into the battery ?
    nope pot.jpg
     
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  16. TMR-JWAP

    TMR-JWAP Senior Member

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    Considering he asked this question almost a year and a half ago, and hasn't been seen since, I'd guess he got something figured out.
     
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  17. tracy ing

    tracy ing Active Member

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    or, he realized if he followed up he would have to prove he was allowed to even buy coffee in his state
     
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