Prius Battery Replacement (GenII) Like you've never seen - NEW Cylindrical Cells

In a serious collision, the pack is cutoff from the rest of the car except for at the pack itself. The main metal bars uptop as well as the metal frame below are untouched. The stock cells are not really very strong, but they require compression to not expand because of the way they are manufactured. That's why that compression is there.

But yes very true that any modification to a vehicle can alter its crash performance as it isn't tested.

 

Yes lithium would be lighter and smaller but it is a completely different animal. The project was to get brand new equivalent cells into my Prius. Panasonic will not sell you Tier 1 cells new, they only go to Toyota Motor Corp. It's sad because I have some nice Lithium Toyota cells at my work but I can't buy them

But with Lithium you would need a bi-directional power board. To "translate" what the Prius requests into what you can use. Without significant custom hardware, it is not possible. It's a totally possible project, but I don't see many advantages now that you can buy EVs from a leading manufacturer. When that wasn't the case, lots of people on Priuschat including myself looked into it.

 

(1) Yes.

(2) I don't know what it does to "condition" but if it is a standard discharge/charge/balance/repeat type conditioning there is no need to do that. These cells are brand new out of a factory. Not sitting around. There is nothing to condition. Now a few years from now, it would be the same advice that they give. Some people would prefer to have a car plugged in and balanced all the time. That's up to you to decide. I never did anything like that with my Prius, and it seemed to last a very long time under heavy abuse.

 

You cannot even get a reconditioned late model year pack for $1000.

If you look on eBay used pack prices go between $800 and $2000. This is a brand new pack.

 

So not for you then. But like I said, this pack has advantages over the stock pack, so it is actually an upgrade for less money. Also to get that $2150 price will require a core charge and refund.

Also in the future, I would like the price point to be a few hundred cheaper. Right now this is bleeding edge and low volume.

 

Yep. There was a time many years ago when you could get a 2-3 year old battery at a junkyard for $200 because nobody knew what to do with it. Now that they are in demand, price is an order of magnitude more expensive. The stock cells I bought to test out my battery rebuild from a reputable seller were 8 years old and cost well over $1000.

 

Curious what you think are "hollow marketing claims". I'd love to rebut. I am an engineer, and I work with batteries and power systems on a daily basis. I sell other consumer electronic, industrial, and automotive devices that I have custom designed to both small and large businesses. In some of those I require batteries and I have contacts in a few plants that make me various types of batteries of a very high quality. I have tested packs from big-brand automotive companies and have millions of dollars worth of equipment at my disposal. Testing my old original cells plus newly refurbished cells plus newer cells in the 2013 Prius C we have, I got a pretty good idea of how these cells perform. The cells that we have produced exceed all these parameters and the like-for-like comparison puts these cells ahead of the Toyota cells. Will they last a decade like the Toyota ones? Nobody knows at this point. However the magic-8-ball says "all signs point to yes".

In addition the mechanical and electrical design of these cells in superior that can be seen with just quick observation. I have 14 battery modules in a pack versus 28 battery modules. If any one of those faults, the entire car is inoperable. By actually pairing 2 modules into 1 larger module, you make inbalances between pairs much less likely to occur as they are all factory and production matched unlike the smaller cells that are paired way down the assembly line in pack construction. Another reason they are serialized, you know exactly where they should go and there is no chance that they get separated in production.

In addition these cells are physically larger in cross-section, i.e. thicker/wider current paths. The internal resistance is lower compared like-to-like. Look up anything on wire gauge and it is the same principle. The wider the current channel, the lower the internal resistance. There is 1 less bus bar connection for each of the 14 modules. And that bus bar connection commonly corrodes, as it is an open air contact to a piece of metal secured by a threaded nut. That will never be as good as a welded sealed connection, it is not possible to be. And the lower the internal resistance, the lower the internal heating, the lower the overall pack heating, ergo longer life due to less heat. And that leads us to...

And the final big one is the size and shape itself. We all know that pack-heat is one of the main killers of hybrid batteries. That's why mountainous driving and high ambient air temperature driving accelerates the aging. With the packs all squeezed together the surface area for all the heat dissipation was just the skinny side, not the large flat side for all cells except the very 2 ends in the battery sandwich. With this design there is airflow around each and every individual cell. Right there that will allow for even distribution of heat. Most Toyota packs have known failures inside the pack. Rarely do we see a failing in Block 1 or Block 14. It is always inside. My hypothesis is heat. It exacerbates the problem and there is no way to get the heat out. A cylindrical cell allows for the air gaps because of its design, it's why your pressurized tanks are all round. Instead of needing to linearly squeeze the cells, the cell casings themselves maintain the pressure required to charge and discharge without expanding.

If you have any specific questions about what you feel are downsides in the design, I am all ears. But as an engineer in this field, I can tell you this was designed to be superior and all testing points to it being superior.