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Anyone who follows EVs knows that thermal management of the battery is a critical issue. If it's too cold, the battery can't transmit all the power needed to the electric motors, and if it's too hot, the battery itself degrades and loses range capacity. There have been lawsuits against Nissan going for years in Arizona because Phoenix-area Nissan Leaf owners started losing like half their range as their batteries died from not being thermally managed. Unbelievably, Nissan did not include any active thermal management system on the first-generation Leaf, or on the current Leaf. Every other manufacturer of electric cars has been including thermal management systems because they are so important, aside from a few compliance cars like the VW e-Golf. Every Tesla model, BMW i3, Fiat 500e, Porsche Taycan, etc. all have active thermal management systems.

Rivian’s VP of Propulsion said that thermal issues are the dominant limiting factor for maximizing EV performance: Charged EVs | Rivian’s VP of Propulsion: Thermal issues are the dominant limiting factor for maximizing EV performance

The above article is a recommended read that details Rivian's approach to heating and cooling. In short, the battery has a dedicated circuit with heating and a chiller. That said, I'd like to learn more about the system.

Rivian is devoting resources to getting the cooling right. I noticed they have a job posting (among many other jobs at Rivian postings) for a "Thermal Analysis Engineer" Rivian Automotive - Thermal Analysis Engineer

Developing, executing, validating and maintaining simulation models of thermal systems architecture including but not limited to powertrain cooling, thermal, controls, and battery system
  • Own and maintain all models and libraries to be implemented for thermal systems
  • Developing and maintaining regression testing to ensure model validity at all times
  • Collaborate tightly with validation team to ensure efficient implementation and validation of new features, components and systems
  • Using commercial tools perform 3D/1D analysis of various powertrain components such as motor water jacket analysis, cooling system, airflow simulation, pumps, Heat Exchanger sizing
  • Collaborate with Body Exterior team and cross-functional support areas to ensure robust design and integration of active grill shutters and sub-systems
  • With thermal architect, define the following components for the thermal system including but not limited to:
o Hoses
o Pumps
o Cabin heater
o Air Conditioning Control Module (HV)
o Heat exchanger(s)
o Refrigerant lines
o Sensors/solenoids/valves
  • Develop and validate 1-D simulation models of vehicle cabin, A/C sub-system, and heater subsystem to wind tunnel tests
  • Work closely with suppliers to accurately size heat exchangers and ensure all system performance requirements are met
  • Coordinate work with powertrain, systems and components, Interior and other functional teams


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2017 Chevy BoltEV, 2016 Chevy Volt, 2017 Toyota RAV4
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Has anyone else been looking at this research study from Penn State? Could be a huge breakthrough that solves the issue of speed of charging EV batteries. This research was using lithium iron phosphate cells, heating them to 140 F before allowed to begin charging, and result was full charge in 10 minutes. Wonder if this would work for lithium ion cells, or would pre-heating to 140 F be injurious or a fire hazzard?

Still haven't heard which supplier Rivian is planning to use for it's battery pack cells. Is it too late to make a change for a battery technology or pack design that may be far superior, or are they too far along to make a change?
 

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Still haven't heard which supplier Rivian is planning to use for it's battery pack cells. Is it too late to make a change for a battery technology or pack design that may be far superior, or are they too far along to make a change?
I bet they're too far along. They're already producing trucks. There's safety/crash/road testing that would need to take place if they change the pack design.
 

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GMC Sierra, Bolt, Sky, Mach E
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Has anyone else been looking at this research study from Penn State? Could be a huge breakthrough that solves the issue of speed of charging EV batteries. This research was using lithium iron phosphate cells, heating them to 140 F before allowed to begin charging, and result was full charge in 10 minutes. Wonder if this would work for lithium ion cells, or would pre-heating to 140 F be injurious or a fire hazzard?

Still haven't heard which supplier Rivian is planning to use for it's battery pack cells. Is it too late to make a change for a battery technology or pack design that may be far superior, or are they too far along to make a change?
I heard a while back it was LGChem, but that could have changed. GM uses them and they work well.

I have seen interesting results when fast charging my Bolt at different temperatures, and it backs up the Penn State article. Phoenix summers get over 110 temps and any time I do a fast charge in the summer I always get 55-56KW charging rates on my Bolt. But a couple of fast charges lately with temps at 40-55 deg, I only get 40-45KW charge rate. There are plenty of articles that demosntrate that lithium batteries cannot be charged fast when cold, they have to be warmed up first so the charge starts slower then gradually rises as the internal temps go up.
 
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