Extreme low humidity levels are crucial to any lithium-ion battery manufacturer as the element reacts easily with any water vapor 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).

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. Today we work with several European battery manufacturers on how to design the most optimal setup.

During second half of 2020 we are amongst others supplying dehumidifiers for two test laboratories and working on a large number of projects in Europe.

 

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 an optimal dry room environment using 1,2 or 3 rotor setup.

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

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. 

Making batteries for electrical cars as green as possible

From time to time, new discussions pop up asking how green electric cars really are.

There is a lot of research on this. Overall mining for the minerals has a significant impact. At Cotes we know our dehumidifiers and put our energy into coming up with the most energy efficient solution for the dry rooms. From what we see from our project involvement, is that we can reduce energy consumption for dehumidifiers by >60 percent. Below we have used recent project examples as benchmark.


How much energy (kWh) does it take in total to manufacturer kWh battery?

  Market Standard
H2 2020
With a Cotes Dehumidifier  Savings

Mining 

250 

250 

- 

Drying/coating/solvent 

19 

19 

- 

Dehumidifiers for dry room 

23* 

7 

69,6% 

Aircon/HVAC 

3

3

 

Other 

17 

17 

 

Total without mining 

62 

46 

25,8% 

Total with mining 

312 

296 

5,1% 

 

*In research from Kelly Dehumidifiers and Aircon/HVAC is set to 26 Kwh. Cotes assumes Aircon/HVAC is 3 and has made a split to make comparison easier. 

Sources:

  • Dai, J. C. Kelly, L. Gaines, M. Wang, Life cycle analysis of lithium-ion batteries for automotive applications.Batteries. 5 (2019), doi:10.3390/batteries5020048.
  • C. Kelly, Q. Dai, M. Wang, Globally regional life cycle analysis of automotive lithium-ion nickel manganese cobalt batteries.Mitig. Adapt. Strateg. Glob. Chang., 371–396 (2019).
  • Cotes 

If car and battery makers want to go green(er) better dry rooms are worth considering. We can help you find the right dry-air solution for your facilities.

 

Contact the team