Chevrolet Volt Battery – Deep Dive 2-Hour Video

Chevrolet Volt Battery


Despite the Chevrolet Volt’s decreasing sales in 2017, it’s still the best-selling plug-in hybrid to date, and its long-range battery and award-winning motor/engine combination is the primary reason why.

The Volt is a series hybrid, and GM calls it an extended-range electric vehicle. It features an 18.4 kWh 355.3 Volt lithium-ion battery pack. The Volt boasts a whopping 53 miles of all-electric range and 420 total miles of range. It starts at $34,095 and qualifies for the entire $7,500 U.S. federal EV tax credit.

Chevrolet Volt

The second-generation Chevrolet Volt

The Volt has seen many years of success for the segment since its inception in 2011. Sadly, its reign may come to an end soon due to long-awaited stiff competition from a multitude of new plug-in hybrid vehicles. Regardless, it seems that as GM moves forward with its new electric vehicle push, the Volt’s days will be numbered.

We won’t try to convince you that watching a two-hour video about a battery is exciting. However, it’s surely fascinating and especially interesting to those who take interest in such things.

It’s also compelling that this is actually taught as part of a class in a four-year bachelor’s degree program at Weber State University in Ogden, Utah.

If you’re only interested in specific aspects of the video, use the timeline below to navigate through. “MUST SEE” sections of the video are designated as such.

Video Description via WeberAuto on YouTube:

2018 Chevrolet Volt 355.2V Li-Ion Battery – Deep Dive

Grab your popcorn and get ready for all the boring technical details you have been craving!

Video Timeline:
*(See note below) Video series introduction at 0:08
Under-vehicle view with battery installed at 3:25
Battery removal at 5:42
Under-vehicle view with battery removed at 7:05

Chevrolet Volt

Chevrolet Volt battery sections

Exposed battery “roll-around” at 11:15
Battery tray at 12:06
Battery tray inspection plug at 12:30
High Voltage safety warning at 14:26
Battery sections at 15:32
Battery modules and power ratings at 16:00
Battery cell groups at 16:38
Battery configuration summary at 19:40
Cell group identification/numbering at 20:50
MUST SEE – Cell group demonstration at 22:50

MUST SEE – Parallel cell group individual Li-Lon cell at 23:30
**(See note below) Cell group Ah rating verses cell group Wh rating error I made at 24:35
MUST SEE – Cell group cooling and cooling plate at 25:45
Battery section 3 installation with lifting adapter (first attempt) at 29:35
Personal Protective Equipment (PPE) usage at 30:50
Battery section 3 installation with lifting adapter at 31:10
Battery cell group electrical configuration at 40:20
MUST SEE – Parallel cell groups and bus bars at 42:50
Overall battery negative terminal at 44:30
Cell group voltage sensing lines at 45:10
Battery cell group voltages at 46:25
0.3V Cell ground voltage differential and cell balancing at 49:15

Chevrolet Volt

Chevrolet Volt battery deep dive

Battery cell voltage testing tool at 50:00
Battery section 2 installation at 57:00
Battery section 1 installation 58:10
Coolant hose connections at 59:15
Battery cable harnesses at 1:05:17
Battery section temperature sensors at 1:06:55
Installation of battery negative cable at 1:08:55
Installation of battery positive cable and series cables at 1:12:25
Battery service disconnect plug discussion and safety demonstration at 1:15:53
Installation of voltage sensing and temperature sensor harness at 1:18:45
Battery Energy control Module (BECM) installation at 1:22:22
Battery relay assembly components at 1:25:00
Battery relay assembly electrical connections at 1:25:27
Battery coolant heater at 1:31:40
Coolant manifold fittings at 1:34:35
HV current sensor (fine and coarse resolutions) at 1:41:15
Positive contactor at 1:42:50
Negative contactor at 1:43:30
Coolant heater transistor module at 1:43:40
Plug-in Charger contactor at 1:44:10
Coolant heater 450V 10A fuse at 1:44:50
Pre-charge resistor at 1:45:20
Pre-charge contactor at 1:45:35
Battery relay assembly low voltage ground circuits at 1:46:50

Chevrolet Volt

Chevrolet Volt battery module 3 (top view)

Coolant hoses at 1:47:35
High Voltage fuses and cover with interlock at 1:50:18
Battery service disconnect plug components at 1:51:54
Service plug high voltage interlock circuit at 1:52:15

420V 350 amp fuse at 1:52:55
Service disconnect plug positions for removal at 1:54:34
Installation of battery relay assembly on the battery tray at 1:56:54
Overall review and battery “roll-around” at 2:01:40

*Series Hybrid Clarification:
The 1st generation Volt is a series hybrid in 3 out of 4 modes of operation of the 4ET50 transaxle. The fourth mode (Electric Only Combined Engine On) is a series-parallel mode.
The 2nd generation Volt’s 5ET50 transaxle has 5 modes of operation. Two modes are electric only, one mode is a series-hybrid mode, and the Two remaining modes (series-parallel) allow the ICE to contribute torque to the wheels through the planet carrier of the input gear set. This transaxle is used in a Malibu Hybrid with only 4 modes (they removed the series mode).

**1st generation Volt battery. If an individual cell is rated at 55.5Wh (using units of measure) Power (Wh) = EMF (V) x Current (A), then the current rating would be Wh/V = Ah. So 55.5Wh/3.7V = 15 Ah rather than the 55.5 Ah I mistakenly said/displayed in the video.

2018 Chevrolet Volt 355.2V Li-Ion Battery – Deep Dive

Weber State University (WSU) – Department of Automotive Technology – Ardell Brown Technology Wing – Transmission Lab.

This is the first is a series of videos on the 2 generations of the Chevrolet Volt. This episode covers the removal and detailed reassembly of the 355.2 volt battery and battery relay assembly from a 2018 Chevrolet Volt. The 2016-2018 Chevrolet Volt batteries are the same. The 2011-2015 Chevrolet Volt battery is similar, but has some minor differences. The components and operation will be similar to any other plug-in hybrid or electric vehicle (minus the engine)

This video helps cover content related to the 2017 National Automotive Technicians Education Foundation (NATEF) Master Automobile Service Technology (MAST) Standard task 1.A.9 “Identify service precautions related to service of the internal combustion engine of a hybrid vehicle.”

W.S.U is a leader in Hybrid and Electric Vehicle education. This topic is taught as part of our 4-year bachelor’s degree program. For information joining the Weber Automotive program, visit:

This video was created and edited by Professor John D. Kelly at WSU. For a full biography, see…

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30 Comments on "Chevrolet Volt Battery – Deep Dive 2-Hour Video"

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They should make a crossover from the design, Chevy is missing a model in the CRV/Rav-4 category.

Sure they do, it’s called the Equinox. Which would be perfect for the Voltec platform for about eight years now.

The Equinox is based on the Malibu, not the same size.

The Volt is a series hybrid

To be a series hybrid, the engine must only provide electricity. BMW i3 is a great example of this.

When a hybrid also gets propulsion (direct thrust) from the engine to move the wheels, it is called a parallel hybrid. Volt is this type.

Yes, welcome to 2018. This has been discussed ad nauseum since probably 2010. The video also says:

“*Series Hybrid Clarification:
The 1st generation Volt is a series hybrid in 3 out of 4 modes of operation of the 4ET50 transaxle. The fourth mode (Electric Only Combined Engine On) is a series-parallel mode.
The 2nd generation Volt’s 5ET50 transaxle has 5 modes of operation. Two modes are electric only, one mode is a series-hybrid mode, and the Two remaining modes (series-parallel) allow the ICE to contribute torque to the wheels through the planet carrier of the input gear set. This transaxle is used in a Malibu Hybrid with only 4 modes (they removed the series mode).

Exactly, the Volt is designed to achieve optimum efficiency. Sometimes it’s an EV, sometimes it’s a series hybrid, and sometimes it’s a parallel hybrid.

John has some major buyers remorse about buying a Prius Prime when, to 90% of the knowledgeable people on any general EV forum, the Volt is so obviously superior.

Prime delivers more efficient EV and HV operation. I see both better KWH/MI and MPG results.

The nonsense around labeling and trying to declare superiority is pointless.

Those real-world numbers tell the true story.

Prime delivers more efficient EV operation for a lousy 25 miles, them it’s game over while the Volt keeps going for another 28 miles before the ice is needed. Of course Prime accelerates so slowly in EV mode it probably seems like more than 25 miles .

“I see both better KWH/MI and MPG results.”

I doubt you see better net MPG results. I also doubt you see better net MPGe.

How many hundreds of miles do you drive between charges?

Brace for cherry-picking

BFD John.

The Prime is a good car for some people, but the Volt has vastly superior EV range, acceleration, and top speed. People like myself value these abilities more than low price and “mpge.”


Lol BMW i3 didn’t they add 2 gallon range extender. Hmm a gas engine to extend range what a unique idea.

LOL. Write a sentence that expresses a clear idea.

Big question I have is if Volt cells are the same as 2015+ SparkEV cells. SparkEV battery is 18.4 kWh LG, but it’s not clear if the cells are the same. If they are, that opens up the possibility of using Volt cells to rebuild SparkEV packs.

(⌐■_■) Trollnonymous


Or build another pack to augment the existing pack.

None of this really matters. The Volt is driven by electric motors fueled by its battery. Battery receives energy via electrical grid OR its on board generator. Only under rare circumstances (so I’ve read) will the ICE provide propulsion – in two years of ownership, I have yet to experience that event. Because of our particular but not unusual driving habits, we MIGHT buy gas twice a year; so far, not since last August and the tank guage indicates 200 mi. range available. That said, the Volt is whatever car you want it to be – plug it in regularly, it’s an EV – never plug in, it will need gas (for the generator). But, make no mistake, from a former Prius owner and in the purest technical sense, it is NOT a hybrid but a brilliantly engineered electric automobile.

The Gen2 Volt provides mechanical propulsion from the engine essentially any time the car is running on gas at highway speeds. (The Gen1 Volt does so at a slightly more restricted way.)

Still, I would say that the Volt is one of the most amazing, yet underrated, technical achievements of the last decade. Even the Gen1 Volt still outclasses every other PHEV on the road.

Spider Dan: I can assure you this is not the case. I drive the first 50 miles of my Weekend trip on electricity – (other than response to winter temperatures) the digital read out of ICE coolant temperature does not rise from ambient air temperature until the battery is depleted, then climbs from 50-70F to 185-205F
If the battery has adequate charge the gasoline motor is not needed at highway speed because the electric motor system is much more powerful than the gasoline engine: Electric uses two motors together: 117 + 64 = 181hp. Gasoline engine is 101 hp.

Read what he wrote again. “Any time the car is running on gas at highway speeds”.

You two are in agreement.

For the first generation Volt, you’re right. The second generation does allow mechanical transmission of power directly from the engine to the tires. Extremely similar to the Prius HSD. This allowed me to drive Albuquerque NM to Savannah GA, getting 44 mpg; and to drive 100 miles each way to my weekend job using <2 gallons round trip. Driving around Albuquerque during the week is all electric. GM describes the changes between Gen I and Gen II at Excerpt: Low extended range is technically an “input split” style of eCVT. In this mode the large motor MGB is driving the vehicle through PG 2 to the wheels with the PG 2 ring gear locked together with the mechanical power from the gasoline engine on PG 1 and the electrical power generated by MGA on PG 1. By adjusting the power generated by and used by the two motors the engineers can put the ICE at its most efficient operating point. This type of power splitting between the gas engine, the battery, and two electric motors was first developed by TRW around 1970 and its modern implementation was patented by GM in 1995 and by Toyota in 1997. It is… Read more »

GEN 1 VOlTecs also mechanically clutch to the wheels when doing steady state highway driving.

The trick of the Gen 2 voltecs is that the engine is constantly geared to the wheels, even in full electric mode with the engine stationary. There are no intervening shaft severing clutches – only a one-way-locking shaft (they call it an additional clutch, but its not that sophisticated, its really just a shaft lock) to prevent the vestigial engine from accidentally turning backwards.

Charles Jack if you go down the highway at a steady 60 MPH, the engine will be locked to the wheels, although a portion of the engine’s power will also be syphoned off by the generator. The clutches operate under no torque conditions, so transitions are usually imperceptible.

(⌐■_■) Trollnonymous

” we MIGHT buy gas twice a year; so far, not since last August ”

That’s the same mentality why some people won’t buy an EV, because they might have to take a long trip twice a year…….lol

I have a 2017 Volt and actually watched this video a couple of weeks ago. I was fascinated. My wife just thought I was nuts.

Serious question here: What happens if you drain your Volt gas tank and leave it empty? Will the check engine light come on and stop running even if you have a charged battery?

Before you run out of gas the car will start sending frequent messages and when it still has miles left it will start recommending gas stations. Too annoying to continue on long, but a good thing.

On a GEN 1 VOlt you’ll burn out the fuel pump. I’ve done it. The car APPEARS to behave gracefully, just calmly shutting down the engine…. But it gets expensive to do so.

Getting a bit long in the tooth. Maybe one of
the reason the Volt is ex post facto in few years.

This guy wears high voltage protective gloves but does not cover his bare arms and then reaches over the top of the battery with exposed voltages?

Clearly he did not pay attention in the safety training. Get an arc flash suit!

Naw, this guy is pretty sharp and didn’t take any chances. The “Charge Plug” (with the main fuse) was out, and so touching anything would have no effect since there is nothing that could complete the circuit. The potential on the various battery modules are at opposite ends of the battery making it pretty safe with the charge plug out.