Rivian technical nuggets gleaned from EPA application docs

[DucRider]

Major takeaways (from Rivian EPA application docs):

1. Confirmed 108s pack architecture using 5A (nominal) 21700 cells. Modules are 8p yielding 40A ea. Nominal voltage of 400, max charging voltage of ~450V.
2. DCFC Max of 210 kW
3. Testing done in conserve and sport mode (then averaged)
4. Conserve mode absolutely disconnects rear motors
5. Tesla method of brake pedal only engages friction brakes. Blended braking mapped to the accelerator pedal if brake hold enabled. Since the accelerator should be lifted when braking, using max regen mode will recovery the most energy when using the brake pedal.
6. Cold weather looks to be a ~40% range hit
7. Useable battery kWh appears to be ~129

From the docs:

• Every vehicle which is covered by this application conforms to US EPA Federal Tier 3 Bin 0 regulations applicable to new Medium Duty Passenger Vehicles and state of California ZEV regulations applicable to new Medium-Duty Vehicles for the 2022 Model Year.
• Maintenance schedule:
  
  
• 4 motors, full torque vectoring capability with 1 motor/gearset per wheel. Drive units are packaged inboard, with priority on maximizing half shaft length to each wheel to enable maximum durability and suspension articulation.
• Front and rear drive units have high level of commonality. The motor, gearbox, and inverter are sub assembled into a drive unit to optimize mass, cost, and package spacing. The motors are the largest part of the drive unit, and the drive unit orientation in vehicle is adjusted to have the motors as low and towards the center of the vehicle as possible, reducing the center of gravity and the vehicle's polar moment of inertia.
• Interior permanent magnet motors and water jacket cooled stator. Motor air space is a sealed "air cavity" that is shared with the Dual Power Inverter Module, DPIM.
• Fully automatic, 2 stage, single speed reduction gearset for each wheel. Left and right gearsets share oil and a common cavity for a given drive unit. The gearsets share many parts and utilize a 12.6:1 ratio on the front and rear drive units.
• Inverters: Front drive units are silicon carbide, while rear drive units are silicone based IGBT's. All drive units share a single capacitor for 2 motors which reduces cost, mass, and package space.
• Drivetrain: Ball spline half-shafts are utilized to maximize half-shaft durability, efficiency, and torque capacity during high articulation suspension events. On the rear drive unit, a modular disconnect is utilized to decouple the half-shaft from the output gears such that the vehicle can operate in FWD. This allows a significant range improvement during low power output and steady state cruise driving events.
• Battery
  • The Battery pack consists of 7,776 lithium-ion battery cells which are arranged in 9 cell modules. The 9 cell modules are assembled into a fully sealed enclosure built from an aluminum frame structure. The lid includes a removable service access panel, and the bottom plate provides protection from ground strikes consistent with the vehicle’s on and off-road capability. Liquid coolant is distributed in parallel to each cell module via the coolant manifold. A Battery Management System (BMS) communicates battery operation with other vehicle systems, controls the contactors, and monitors current, voltage, and isolation measurements. The BMS also monitors sensors for detection of gases, water, and bottom plate puncture.
  • Battery pack nominal capacity is 360 Ah based on a constant current C/5 discharge rate.
  • The thermal management system for the high voltage battery is a liquid coolant system. A pump circulates coolant thru the battery and a refrigerant-cooled chiller to extract heat and lower the temperature of the battery. In cold weather, an in-line heating element is used to heat the coolant to raise the temperature of the battery.
  • Battery management control system is programmed to prevent a state of under-voltage or over-voltage per the voltage limits defined by Rivian. Contactor opens and DTCs are set when voltage of the 9 module 135 kWh battery is below 216 V or above 459 V.
• Regenerative Braking System
  • The regenerative braking system can use up to all 4 electric propulsion motors to convert the vehicles kinetic energy to electrical energy which is stored in the vehicles high voltage battery.
  • The regenerative control logic uses two main inputs, acceleration pedal position and vehicle speed to determine a desired regenerative braking torque. The requested braking torque is then distributed between the front and rear axles based on the vehicle state, axle disconnect status, and calculated normal force on each axle. The regenerative torque is limited when the vehicle experiences low wheel traction events (e.g. ice or snow).
  • The percentage of braking performed on road by each axle is constantly changing and redistributing. It is based on the driver demanded torque and has been optimized for vehicle dynamics and range attributes.
• Overlap of friction brakes and regenerative braking
  One pedal driving is the default, in this mode, fully releasing the pedal yields the maximum regen level. And about halfway through the pedal travel is the neutral point, where regen is limited. As the driver manually increases primary service brake pressure and friction braking torque, the vehicle regen level will proportionally ramp down to 0 Nm based on the driver braking pressure. The ramp profile is affected by many factors. When autohold is active and the vehicle approaches standstill, the braking torque will blend from motors to friction brakes.
• Charging:
  • AC Level 1 Charging at 120 V / 12 A
  • AC Level 2 Charging at 240 V / 48 A
  • DC Fast Charging at up to 210 kW
• Range:
  • Tested in both Conserve and Sport modes, then averaged
  • Difference of ~12% (Slightly less impact on the hwy vs city) between the modes - Conserve Mode should get you +6% range, Sport -6%
  • Cold Weather (20 degrees F) phase (performed on the City cycle only):
    Conserve mode = -27%
    Sport Mode = -57%
    Average cold weather (city) impact -41%

A few questions answered - more questions raised

EDIT: For those looking for the documents
https://iaspub.epa.gov/otaqpub/publist1.jsp
Select "Applications" for document type and "Rivian" for manufacturer (the others are not required), then search.
The older docs have a few more details about the trucks, the newest has all the test results.

The range/test figures above are only for the R1T. I haven't looked closely at the R1S results yet but would expect them to be similar

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[kanundrum]

Amazing find!

 

[electrictaco]

Conserve mode = -27%

This seems good even if it's only in the city cycle.

 

[eggpaul]

Conserve mode get 6% more range than All purpose?

 

[DucRider]

This seems good even if it's only in the city cycle.

27% is the COLD WEATHER penalty when in Conserve mode.

The overall rating looks to be about 6% better in conserve

Conserve Range: 334 miles
Sport Range: 293

 

[electrictaco]

27% is the COLD WEATHER penalty when in Conserve mode.

Yeah I know, but they only performed the Cold Weather Testing in the City Cycles.

 

[PastyPilgrim]

27% is the COLD WEATHER penalty when in Conserve mode.

The overall rating looks to be about 6% better in conserve

Conserve Range: 334 miles
Sport Range: 293

That would mean if you stick to conserve mode in winter you'd have ~244mi range? Not too bad, but adding in AT tires and Rivian's recommended 70% charge threshold for daily driving it's less than ideal.

 

[Speedrye]

At least one of today's reviews got the Conserve/Sport blended EPA rating right! Maybe journalism isn't dead afterall, it's just on life-support.

 

[Diddy123]

Very informative. Thanks @DucRider for posting and decoding for those less informed about these things, like myself.

 

[PastyPilgrim]

Towing aside, I wonder what the lowest range you could get is.

Winter + Sport Mode + Offroad package + AT tires + Min Regen + ???

It's the all new Rivian Range-Killer Challenge!

 

[DucRider]

That would mean if you stick to conserve mode in winter you'd have ~244mi range? Not too bad, but adding in AT tires and Rivian's recommended 70% charge threshold for daily driving it's less than ideal.

All of the Cold weather data is for the CITY (UDDS) portion only
No data is available for hwy or the combined rating.

City 20 degrees - Conserve mode - adjusted range = 259 (actual test result = 357)
City 70 degrees - Conserve mode - adjusted range = 355 (actual test result = 491)

 

[Diddy123]

Towing aside, I wonder what the lowest range you could get is.

Winter + Sport Mode + Offroad package + AT tires + Min Regen + ???

It's the all new Rivian Range-Killer Challenge!

+ charging on the "Daily" plan + Driving at 90mph + Driving uphill + Towing a hippo

 

[Inkedsphynx]

I'm glad it rarely gets to 20F where I am. That will mostly come into play when I want to hit the mountains and throw some snow around, but those will be short trips for me so shouldn't be an issue at all (esp if I can charge up there and then regen all the way down the mountain).

Great details to add to all the reviews coming out. Thanks for digging this all up!

 

[Speedrye]

6949lb curb weight as tested. (R1T, Cinnamon)

6916lb curb weight as tested (R1S, Madison)

 

[cohall]

I'm a dummy, so please be patient with me...

Does the impact of the cold effect the range the entire time you're driving the vehicle, or just as it's "warming up"? I'm think about my specific use case in that...My garage in Denver stays somewhat warm even on cold days - say 40 degree. But, If I'm driving up to Breckenridge where it's 20 degrees or zero degrees am I going to be paying the cold penalty even though I started and got the vehicle warm prior to hitting those extreme temperatures? Or is the impact much reduced?

Sorry if that's a confusing question.

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