Batteries - Crash Safety

[chromedome]

I am really interested in purchasing a used Prius for my family. One of my friends asked me two good questions that I am hoping someone can answer. I really like the idea of getting 50mpg, but I want to make sure that I think through this.

1. What prevents the batteries from rupturing during an accident? You then have the battery acid and fumes (explosion) to worry about.

2. Is the high voltage cutoff by the computer when the vehicle is in an accident?

Regards,
David

[FL_Prius_Driver]

Originally Posted by chromedome

I am really interested in purchasing a used Prius for my family. One of my friends asked me two good questions that I am hoping someone can answer. I really like the idea of getting 50mpg, but I want to make sure that I think through this.

1. What prevents the batteries from rupturing during an accident? You then have the battery acid and fumes (explosion) to worry about.

The individual modules are permanently sealed (no caps to knock off). Then these modules are bolted together as a rock solid unit, then covered with a shield. It is then located in the midsection of the car as far away from any accident damage as it can be located.

Originally Posted by chromedome

2. Is the high voltage cutoff by the computer when the vehicle is in an accident?

Yes. The high voltage battery isolates itself from the rest of the vehicle if the car is turned off or loses 12 Volt power. Additionally, there are automatic shutoffs if any battery current is detected not being carried on the correct wires. Specifically, all the High Voltage Battery cables are covered with a protective ground shield. If any accident causes any HV battery wire to come into contact with this shield, then the battery completely isolates itself from the car.

[dogfriend]

Also see:

https://techinfo.toyota.com/techInfo...s/2ndprius.pdf

[tochatihu]

Prius does have a small conventional 12 volt lead-acid battery, which has the acid rupture potential mentioned above. However the large NiMH battery does not contain acid. Actually it's pretty much the opposite; potassium hydroxide. Safety responders are instructed to flood the area with water if they suspect a rupture. Add boric acid also, if you have any handy.

The other automatic shutoff (following FL above) comes from the impact sensors. If an airbag is assigned to deploy, the HV system turns off.

[TonyPSchaefer]

Yeah, this question comes up from time to time but it's good to keep it in our minds.

I remember someone mentioning physical disconnects. As mentioned above, in the event of an accident physical switches are switched severing power. I remember a could threads in which someone was in an accident with airbag deployment. They felt that the car was solid enough to be able to drive onto the flatbed but they couldn't start the car. It turned out that the airbag deployment triggered the HV battery sever sequence.

[dogfriend]

From the Emergency Response Manual (linked above):