Can electric cars become greener and cheaper?

Yes, they can! Lithium-battery manufacturers can save millions with better dry room setups and save the world from tons of Co2 if they apply the right energy strategy for their dry rooms using Cotes dehumidifiers. Seeing as the battery pack of an electric vehicle is the most expensive part, there is huge potential for reducing the cost of electric vehicles.

 

The BATTERY Challenge

Extreme low humidity levels are crucial to any lithium-ion battery manufacturers as the element reacts easily with any water vapour to form dangerous combinations of lithium hydroxide, hydrogen or reduce the quality of the batteries. So significant amounts of energy consumption are involved in lithium-ion battery production stems from dehumidifier operations in key dry-room areas to keep humidity levels well below one percent (-40C dew point).

 

The Solution

Cotes has delivered and installed more than 100 specialist dry room systems for use in lithium-ion battery production around the world and been presented to various setups and benchmarked several concepts. See an example here. Today, we work with several European battery manufacturers on how to design the most optimal setup.

Up to 60% of the energy used in lithium-ion battery manufacturing is used for dehumidification. With Cotes dehumidifiers you could reduce that energy consumption by up to 72%.

Dehumidifying a dry room can be done as efficient as 3 kWh/kWh (energy consumed to produce one-kilowatt battery capacity) by smart regeneration of air and excess heat. However often a simple dehumidifying solution is selected, using up to 12 kWh/kWh. Cotes has seen examples up to 30 kWh.

Below is a figure comparing kWh energy consumption per kWh-battery produced in a dry room using 1,2 or 3 rotor setup.

Energy consumption with a 3 rotor setup and reuse of excess heat

But improving your energy efficiency with just 9 kWh/kWh has a huge impact on your bottom line. For an 8 GW factory, it’s the same as 72.000.000 kWh a year or 2,9 million EUR saved annually (assumed electricity price is 0.04 EUR/kWh). For the environment, you will reduce Co2 emissions with app. 30 tons annually (depending on your energy mix).

In the race for cheap battery capacity, every Kwh saved matters if manufacturers want to stay competitive. Traditional lithium-ion battery production requires high-exergy sources of energy, such as steam, gas or electricity. With smart adsorption dehumidifiers, you can instead draw much of the energy required from low-exergy sources, such as waste heat, solar panels or other low-cost thermal inputs as you are sending dry air back into the system for additional dehumidification. A bit like a car’s turbocharger.

According to the International Energy Agency, at least 20 Li-ion battery factories with an annual production volume of several gigawatt-hours of Li-ion battery capacity (GWhc) are currently being commissioned.

Norhtvolt’s factory in Sweden is planned to manufacture 8 GWh of batteries annually and once fully constructed, capacity is planned to reach 32 GWh. Tesla Gigafactory 1 in Nevada, USA has a planned Li-ion battery cell production capacity of 35 GWh, with an additional 15 GWhc of packs from cells manufactured elsewhere.

If car and battery makers want to go green(er) then they should be considering Cotes dehumidifiers.

About the author
Michael Holm is Cotes CCO and welcomes your questions: [email protected]