NexPower V3 hybrid battery unveil - Sodium-ion battery

The BYD Dolphin, and yes it sells for ~$13.5k in China, and ~$28k in Europe, and ~$21k in Mexico. There's been a few test mules for them up in Michigan, presumably something to do with Ford's Skunkworks cheap EV team Farley has been talking about. The price is much lower in China due to no import tariffs (obviously), and very very high EV subsidies.

 

Why then does the plug-in Prius consume more fuel when the battery is low than a regular Prius? It has a bigger battery. It may not be more efficient, but it is slightly worse in terms of performance, both in the city and on the highway.
Oh no, the damn law of conservation of energy.

 

because a larger heavier battery requires more fuel from the engine to drive under the additional load...

 

Agree.

But if the battery has the same or less weight and is able to store more power, then there should be increased MPG. Which is what NexPower is claiming.

 

Too much social media has taught me to no longer care about wanting to know "what an M2 or Dolphin is" but I'll have to admit I am sorta curious? Are those the names of BYD cars?

 

From what I've read, daily driving habits in these plugins have far more influence over the motor-battery vs. ICE interaction than in regular Prius.

 

Interesting. My understanding was that NexPower was approaching 10k packs.

 

Can't wait to test this claim out on the bench.

Your units don't work. I assume you're saying you have a capacitor large enough to source all the energy required to charge the pack from empty to full in a few seconds? If so, you're going to need a REALLY large capacitor. The derivation below gives every benefit of the doubt to your claim:
-assuming charging pack from empty to full consumes 450 Wh, which is ~1.6 MJ.
-assuming the average pack voltage from empty to full is 220 VDC.
-then you'd need a 120 farad, 450 volt capacitor (1.6 MJ * 4 = 0.5 * C * (220/.67)^2).
-For reference, a 2 mF, 450 volt capacitor is about the size of a can of coke. You'd need QTY60000 of these capacitors, which would consume 14 cubic feet of volume. For reference, that's the same volume as QTY4 typical backyard swimming pools.

We could certainly get the size down by switching to super capacitors, but of course their instantaneous current delivery is going to be too small.

The real takeaway here is just how much energy we can cram into chemical reactions, compared to charged plates.

...

 

Regarding the various posts saying "More Ah means more MPG", the only compelling argument I've read so far is those who drive up and down steep enough mountains that the smaller pack would fully empty/charge when going up/down. Otherwise, without a PHEV option that charges from the grid, all the energy ultimately comes from gas... area under the curve (i.e. energy) makes it essentially irrelevant how fast you charge the battery (within reason).

I know I'm late to the party, but this is a planned feature in my LiBSU product... my existing Honda Insight product (LiBCM) already has this functionality implemented and working without issue for several years now.

This is a key long term benefit for team sodium. Still too new for my taste, but someone has to early adopt it.

I know of one person who experienced a thermal event without the Signal Soother installed. The SS only makes it twice as likely to happen... odds are still fair without SS present.

 

Did this occur on a stock OEM pack?

 

That's just the capacitor itself. Also, following the NFPA 70E annex on safe working practices around capacitors, a capacitor with those specs would require an enclosure to keep out anyone lacking appropriate PPE (both shock and thermal), and would need the respective approach distances to be calculated and posted for arc flash hazard, hearing protection, and lung protection. There is no PPE that's useful inside the lung protection boundary, so personnel need to be kept outside of that distance at all times when the cap is not verified discharged and hard grounded. Because the proposed cap is well over 100 kJ, "an engineered and redundant system shall be used for remote testing and grounding." Once the safe discharge has been verified remotely, personnel can make their approach.

This is not a device that will end up on the kitchen counter like Mr. Fusion.

 

There are quite a lot of problems there, even if it is possible to send parameters about the battery charge and current to the hybrid system ECU, then in any case there are limitations on the power of MG2 and the inverter. The second problem is the cost of a high-capacity battery and the development of a charger for it. As for me, this will be of interest only to enthusiasts.

 

No, their's was a NexCell V2.x pack.

It's insane that the bus bars on systems like this must be bolted down every foot or so. Without mechanical fasteners, the insane rail currents generate enough force to bend the bus bars.

In the late 1990s, my dad was a structural engineer on UT Austin's rail gun project. During one of their early tests they experienced an overcurrent event that generated enough force to rip the several inch wide bus bars clear off their mounts. As a kid, I remember seeing their capacitor bank, which stored something like 30 MJ... my hazy memory is that it was QTY6 school bus sized capacitors.

I agree. It's really insane to understand the specific energy differences between various materials.

I don't intend to use the existing MG2 or inverter to charge the vehicle. Instead, I typically use off-the-shelf current sources, which are relatively cheap because they are used to power pretty much all modern LEDs. For example, a 150 watt CC power supply only costs $30 in bulk, and a 1500 watt CC supply only costs $300 in bulk. I don't intend to support charging levels faster than level 1... IMO not really worth the effort in a PHEV, which has a gas tank. IMO overnight Level 1 charging is really all you need for a PHEV.

For those enthusiasts that want to charge faster, there are a couple people in the Honda Insight community working on LiBCM-specific OpenInverter adaptations. For those unfamiliar, this basically uses a reclaimed Tesla inverter with an open source replacement PCB that allows level 2 charging. I'm never going to officially support that, but I'm all about helping other people achieve this integration.

 

I meant that the power of the MG2 is not enough for normal driving only on electric power.

For an external charger, you need the power supply itself, wires, connectors and other stuff that costs money. At first it seems that this is a small expense, but when you count everything together, it turns out that it is not worth it.

 

Ah, thanks for the additional context. Yeah, sorry, I was referring to the plug-in charger component, whereas you were referring to the electric motor only component. Note that I already have a product (LiControl) that allows G1 Insight owners to drive 'electric only'***. However, I don't intend to design a similar product for the Prius, as I don't own a Prius, hence I wouldn't want to take on this passion project.

***clarification: the G1 Insight's electric motor is essentially bolted to the flywheel. Therefore, the engine still has to rotate even when only the electric motor is supplying traction power. Even though the OEM motor only originally supplied ~6 kW continuous, we have several years of driving feedback wherein we can drive that little motor at 24 kW for as long as we please.

 

maybe I'm lost in the sauce with my projects and am missing something here. where do we see no increased mpg with a higher capacity battery?

 

When weight starts to lower mpg. Its not by much, but you also dont gain any mpg by much either unless your battery is aged very old to where a lot of amps will hold just enough to make the prius functional. The cons is the cost, weight, and space lost.

 

Cost is certainly an issue.

But the Nexpower holds more power while weighing less, and takes up the same amount of space.

For those that live in even marginally hilly areas, that combination seems bound to increase overall MPG. For instance, my stock battery is routinely filled to capacity simply by going down a few modest hills.

 

Agree. There should be increased MPG.

Don't understand the logic of those claiming otherwise.

 

still where is it documented the larger capacity cells don't increase mpg?