LOW RELATIVE HUMIDITY AND DEWPOINT REQUIREMENTS WITHIN LITHIUM BATTERY DRY ROOMS

Lithium Battery (Li-ion) powering the future

In the 21st century, humanity has become an engine, participant, and witness of the revolution in the energy sphere. We harness renewable energy sources (RES) such as sun, wind, and water movement. In recent years we have begun to understand the importance of preserving the environment in which we live. One particular area of focus, is the increasing use of electrified means of transport, this is set to become an important step forward in the goal of reducing inner city pollution.

In the whole technological chain of the power system, from production to the final consumer, the task of accumulating generated energy (including mobile energy such as gadgets and electric vehicles) and its use has become increasingly critical towards achieving the goal of reducing carbon footprints. The most common energy storage element in production today, is the lithium-ion battery (Li-ion).

 

MDC4000DD Single Rotor - Ultra Low Dewpoint Series

About Lithium Battery Dry Rooms and the importance of low dewpoint dehumidification systems - Research & Production

Lithium battery production, takes place in controlled environment rooms now commonly referred to as “Dry Rooms”. The main criteria by which “Dry Rooms” are classified is in the low relative humidity (RH) or low dew point (tdp) requirements. Requirements are often expressed in dewpoints as the equivalent relative humidity is close to zero. Low dew point dehumidification systems are the crucial element required in lithium battery production. Dewpoint requirements within dry rooms currently range from minus 35.0˚Cdp to as low as minus 60.0°Cdp, this point is measured in the return air stream as represents the average across the room. At critical areas such as electrolyte fill the supply dewpoint required can be as low as minus 70.0°Cdp. Low dew point dehumidification is the crucial factor required to prevent the lithium from absorbing the humidity from the air.

Violations of parameters, particularly at critical stages of production, such as electrolyte, will lead to a decrease in the quality of the Li-ion battery. To maximise product quality, microclimates are often created at critical production points, where the moisture level in the air should be close to zero as possible.

The next generation of batteries currently in design, are showing an increasing demand for even lower dewpoints of minus 75.0°C and below, as such, energy consumption for maintaining the dry rooms, will continue to form a significant part of the cost of producing lithium-ion batteries.

To minimise this production cost, the dry rooms should be constructed in a manner to reduce infiltration, to as low as practicable. Crucially the room air drying systems, should be designed to be as energy efficient as possible, and should be able to react quickly to changing external conditions. With these goals in mind, DT Group are focusing on the utilisation of dual rotor desiccant dehumidifiers, to provide continuous supply of low dewpoint air into the manufacturing spaces. These innovative designs are set to become the new benchmark across the battery industry.

Effects of Uncontrolled Humidity within Battery Dry Rooms

During production, Lithium batteries can be severely affected by exposure from uncontrolled temperature, this ultimately will lead to impacting on the final quality of the battery through:

  • Reduced product life
  • Reduced performance and charging capacity
  • Long term safety concerns including chances of explosion

Consequences of Uncontrolled Humidity within Battery Dry Rooms

Pure Lithium metal is extremely sensitive to even the smallest amounts of moisture in the air. The slightest of exposure to moisture leads to reduced performance and reduced product life of the Lithium-ion battery.

Battery Dry Room Environmental Recommendations

  • Moisture level in Lithium-ion battery processing areas should be less than minus 35°C dewpoint. 
  • Room temperature should be maintained at 25.0°Cdb with tolerance of ± 2.0°Cdb
  • The air change rate in the production room should be between 20 to 50 air changes per hour with
    only minimal fresh air introduction for positive room pressure and ventilation for workers  


Depending on the established technological criteria of the particular battery dry room production process each project is considered by our specialists individually, some of the features are presented below:

  • Manufacturing of all elements in stainless steel AISI316, including heat exchangers
  • Allowance for large volumes of fresh air content, to meet extract process requirements
  • Lack of zinc-containing materials
  • Maximising energy efficiency, by the utilization of heat recovery systems
  • Dehumidification systems with either single or twin desiccant wheels
  • Optional additional features

The DRY AIR and Desiccant Technology Group team are always ready to work with you, to solve any problem and provide an energy efficient, reliable solution, with the goal of achieving the required microclimate in your DRY ROOM project.

DT Group Battery Dry Room Twin Rotor DD Series

The MDC 50000DD-2DW has been specifically designed for use in low dewpoint industrial scale applications, with supply dewpoints down to minus 70.0°Cdp (Subject to inlet condition). Currently the most compact 50000 m³/h twin rotor low dewpoint unit available on the market today, allowing for ease of positioning and lower cost installation. The twin rotor design provides operators with reduced pull down times and optimised energy consumption via the in-series internal heat recovery system. The MDCDD-DW series delivers market leading energy consumption, whilst achieving the ultra low dewpoints required for next generation battery production.

 



The MDCDD-2DW Series features two high performance active silica gel rotors.

· Primary rotor

The primary rotor features three sectors that split the incoming airflow between the process, purge, reactivation. The purge sector exists to recover heat that would otherwise be transferred into the process sector, the removal of the heat also acts to prime the rotor readying it for deep drying the incoming process air. The pre heated regeneration air then passes through the primary regeneration heater which is regulated to a maximum of 140°Cdb.

· Secondary rotor

The secondary rotor features two sectors. The reactivation air is taken from the outlet of the primary reactivation system, temperature is then regulated via the secondary reactivation heater according to system demand. The fresh air first undergoes a two stage filtration before being precooled and finally passes through the secondary rotor before mixing with the room return air.

· Post treatment

MDCDD-2W features post treatment coils for temperature regulation. Optional final filtration to H12 available to maximise terminal HEPA lifespan.


 

Contact one of our team today to find your low dewpoint solution...