What is Lithium Battery Cleanroom?

Guidelines for Clean Room Manufacturing of Electric Vehicle Batteries
1.What ISO level or cleanliness is required for the lithium batteries cleanroom?
  The cleanliness of electric vehicle batteries cleanroom depends on the specific process.
  Below chart can be used as a reference.

2. Do lithium battery cleanrooms need to comply with any specific industry standards (e.g. cleanroom classification according to ISO 14644-1)?
  ISO 14644-1 regulation is an international standard for clean room classification, and its indicators reflect the degree of dust (particulate) content in the air of the environment. High dust concentration leads to low cleanliness, while low dust concentration leads to high cleanliness. The cleanliness level is usually determined by the maximum allowable number of particles per cubic meter of air, and clean workshops for electric vehicle battery manufacturing also follow this standard.

The design standard of manufacturing electric vehicle batteries
1. What equipment and processes will be accommodated in the clean room?
  A lithium battery clean room is a space that strictly controls parameters such as air cleanliness, temperature, humidity, pressure, and noise. It is mainly used in various stages of lithium battery production to ensure product quality and production stability, while avoiding pollution and cross contamination during the production process.
The following are some of the main equipment and processes that will be included in a lithium battery cleanroom:
â–¶ Cleanroom crane: Used for material handling, especially in lithium battery workshops, it plays a key role in improving production efficiency and convenience.
â–¶ Air shower equipment: used for clean treatment of personnel and materials before entering the clean room, reducing pollution.
â–¶ Air purifier (FFU): Used to filter and purify the air, ensuring that harmful substances such as dust particles are effectively removed from the air
â–¶ Modular cleanroom equipment: It is a convenient and efficient clean space module that can quickly improve the cleanliness of the area. It consists of a fan filtration unit (FFU), suitable for quickly creating higher cleanliness spaces in existing ordinary or low cleanliness factories. In the production process of battery manufacturing, such as coating, rolling, slitting, die-cutting, liquid injection, sealing, baking, etc., it is necessary to use modular cleanrooms with high cleanliness levels in a targeted manner.

2. Main processes
â–¶ Production process control
  Graphic layout design: reasonably design clean areas, auxiliary areas, personnel purification areas, and other areas to ensure smooth production processes and reduce cross contamination.
â–¶ Environmental parameter control
  Air cleanliness: The air cleanliness is ensured through an efficient air filtration system to meet the cleanliness requirements of different production areas.
â–¶ Temperature and humidity control
  Strictly control the temperature and humidity in the clean room to ensure the stability of the lithium battery production process and product quality.
â–¶ Personnel and material purification
  Personnel purification procedure: before entering the clean room, personnel need to go through the air shower and changing procedures to ensure that no pollutants are brought in.
Material purification process: materials need to undergo purification treatment before entering the clean room to avoid introducing external pollution.

What are production capacity and workflow?
  Overview of production capacity and workflow in lithium battery manufacturing workshop:
Production capacity
  The production capacity of lithium battery manufacturing workshops mainly depends on factors such as equipment scale, technological level, and management efficiency. The specific production capacity needs to be determined based on the specific factory and production line. Generally speaking, modern lithium battery manufacturing workshops can achieve large-scale, automated production, thereby improving production efficiency and product quality.
Workflow
  The manufacturing process of lithium batteries is complex, which involves multiple key steps. The following is the workflow of the lithium battery manufacturing:
â–¶ Material preparation
Preparation of positive and negative electrode materials: mix active materials, conductive agents, binders, etc. to form a slurry.
Preparation of electrolyte: mix organic solvents and salts, filter and remove impurities, etc
â–¶ Polar film production
Coating: apply the slurry onto a current collector (such as aluminum foil or copper foil) and dry the solvent.
Pole cutting: cutting the coated pole into the desired size.
â–¶ Cell Assembly
Stacking or winding: According to the design requirements, the positive and negative electrode pieces are stacked or wound with the diaphragm to form a battery cell.
Assembling soft pack batteries: Insert the battery cells into aluminum-plastic film or plastic casing and complete the packaging.
â–¶ Injection and packaging
Injection: injecting electrolyte into the assembled battery.
Sealing: complete the sealing process of the battery.
â–¶ Testing and Inspection
Activation detection: activate and conduct preliminary testing on the battery.
Performance testing: testing parameters such as battery capacity, voltage, internal resistance, etc.
â–¶ Quality Control and Safety Management.
Quality control: strictly control the quality of each steps in the entire production process to ensure that the product meets the standards.
Safety management: ensure the safety of the production environment and prevent accidents from occurring.

What's the requirements of temperature and humidity?
See below chart as a reference

How to control the particle and pollutants?
  The control of particle and pollutants in lithium battery cleanrooms is essential to ensure product quality and production safety.
The following are the main measures to achieve this goal:
â–¶ Air cleanliness control
Air filtration system: use high-efficiency air filters (such as HEPA filters and activated carbon filters) to remove pollutants such as dust and harmful gases from the air.
Filter performance and replacement cycle: Ensure the accuracy of air filter performance and replacement cycle to maintain high cleanliness.

â–¶ Particle control
Dust prevention measures: Take appropriate dust prevention measures, such as regular cleaning and maintenance of equipment, control of personnel and material transportation, etc., to reduce the generation and pollution of particles.
Equipment maintenance: Regularly inspect and maintain production equipment, especially moving parts such as bearings, gears, and transmission belts, to reduce dust generated by mechanical wear and tear.

â–¶ Airflow organization
Reasonable design of airflow direction: By designing the airflow direction reasonably, reducing vortices and dead corners, controlling the fresh air volume and exhaust air volume, optimizing the airflow organization, and improving the performance of the clean room.
Positive and negative pressure design: Adopting positive and negative pressure design to prevent external pollutants from entering the clean room, while ensuring the discharge of internal dust.

â–¶ Temperature and humidity control
Stable temperature and humidity: Choose appropriate air conditioning systems and temperature and humidity control equipment to ensure stable and accurate temperature and humidity in the workshop, reducing product defect rates.
Regular maintenance: Regularly maintain and calibrate the thermometer and hygrometer to ensure normal operation.

â–¶ Personnel management
Personnel permissions and quantity control: Control the number of personnel entering the clean room, and monitor the information and quantity of personnel entering and leaving the clean room in real time.
Hygiene habits: Staff should develop the habit of washing hands and showering frequently, not using cosmetics, not wearing watches and jewelry, and not bringing personal belongings inside.
Requirements for Clean Clothes: Personnel must wear clean clothes, gloves, masks, hats, clean shoes while entering the clean room, and enter through the clean passage.

â–¶ Material Management
Material purification measures: Materials entering the clean room should use non polluting materials and effectively eliminate particles and microorganisms on the outer surface before entering.
Material channel: The purification path of materials and people are set separately and independently, and the entrance and flow direction of materials are separated from people, avoiding crossing back and forth as much as possible.

â–¶ Selection of Cleanroom Decoration Materials.
Carefully select building materials that meet the requirements to avoid the release of toxic substances and the generation of dust;
Cleverly plan the clean room based on the cleanliness level and production processes, including design elements such as positive pressure, negative pressure, filtration system, ventilation system, and air purification system.

Other requirements and processes
â–¶ Cleaning and disinfection
Regular cleaning: Develop cleaning and disinfection policies and procedures, specify which cleaning agents and disinfectants to use, as well as the areas to be cleaned and the frequency of cleaning.
Equipment cleaning: Regularly clean and wipe production equipment to reduce dust accumulation and secondary pollution.
â–¶ Training and Education
Personnel training: Provide regular training for staff, emphasizing the requirements of clean room work, such as changing procedures, hygiene requirements, behavioral habits, precautions, etc.

What type of floor, wall, and ceiling materials are suitable for cleanroom?
Material selection for lithium battery cleanroom floors, walls, and ceilings.
â–¶ Floor material
Anti static PVC flooring: anti-static, suitable for lithium battery production environments that are sensitive to static electricity. This material also has good wear resistance and easy to clean.
Epoxy resin flooring: wear-resistant, chemical resistant, easy to clean, suitable for various types of clean room decoration.
Aluminum-alloy raised floor: anti-static, suitable for environments that require high dust and static electricity prevention, while also facilitating the laying of cables and pipelines.

â–¶ Wall material
Sandwich panel：good air tightness and corrosion resistance, suitable for walls and ceilings in clean rooms. Core materials can be selected from rock wool, silicon rock, glass magnesium etc. to meet different insulation and fire protection requirements
PMMA (acrylic)/PC panel: smooth surface, good sealing, low particle emissions, suitable for environments requiring cleanliness.
Stainless steel plate: corrosion-resistant, durable, easy to clean, suitable for cleanrooms that require high cleanliness and durability.
Tempered glass: corrosion-resistant, easy to clean, durable, suitable for cleanrooms that require high corrosion resistance.
â–¶ Ceiling material
Purified aluminum profiles: with good air tightness and corrosion resistance, suitable for ceiling in clean rooms.
Sandwich panel: the same material as the wall, suitable for suspended ceilings, with good air tightness and corrosion resistance.
Stainless steel plate: corrosion-resistant, durable, easy to clean, suitable for cleanrooms that require high cleanliness and durability.
â–¶ Noise monitoring
Although there is no provision for this project in the Specification, noise level is also an important monitoring indicator in actual testing. Excessive noise may affect the work efficiency and health of production personnel.
â–¶ Illumination monitoring
The illumination of the clean room is also a part of monitoring, and appropriate illumination ensures the smooth progress of production activities.
â–¶ Maintenance of equipment and facilities
The equipment and facilities in the clean room need regular maintenance to ensure normal operation. For example, air purification systems should be regularly maintained to ensure normal operation and provide a clean and safe environment for production.
â–¶ Waste disposal
It is necessary to establish a scientific waste disposal process to ensure timely and proper disposal of waste and prevent secondary pollution to the workshop environment.

Maintenance and prevention
  Maintenance and preventive measures are crucial to ensure the efficient operation and product quality of lithium battery cleanrooms. Here are some key maintenance and preventive measures:
â–¶ Strict entry control
Personnel training and authorization: Ensure that only trained and authorized personnel enter the clean room. Before entering, inspection and admission procedures should be carried out, including wearing appropriate personal protective equipment such as dust-proof clothing and shoe covers to prevent foreign matters from entering the workshop.
â–¶ Cleaning equipment and tools
Regular cleaning and maintenance: Regularly clean and maintain production equipment and tools to ensure their surfaces are clean and dust-free. Use specialized cleaning agents and tools to avoid foreign matters residue.
â–¶ Reasonable workflow and layout
Optimize production process: Optimize production process and workshop layout to ensure that the direction of equipment and personnel movement corresponds to the flow of products, avoiding cross contamination and the spread of foreign matters.
â–¶ Strict cleaning procedures
Develop cleaning standards: Develop cleaning procedures and standards, including regular cleaning of workshop floors, walls, ceilings, and other surfaces, as well as equipment and workbenches. Use appropriate cleaning agents and tools to avoid the generation of dust and foreign matters.
â–¶ Air filtration and exhaust system
HEPA filter: Assembly clean air treatment system equipped with HEPA filter to filter and purify the air. Ensure the normal operation of the exhaust system and eliminate odors and foreign matters in the workshop.
â–¶ Foreign matter monitoring and detection
Install monitoring equipment: Install foreign matter monitoring and detection equipment, regularly inspect and monitor the workshop, and promptly detect and eliminate foreign matters.
â–¶ Training and Management
Employee training: Train the staff on how to operate and manage the workshop correctly to reduce the generation and spread of foreign matter. Establish strict management systems, including regular inspections, monitoring and maintenance, to ensure the cleanliness of the workshop. 
â–¶ Regular review and improvement
Audit and evaluation: Regularly conduct audits and evaluations of workshop cleanliness, improve and optimize according to actual situations, and enhance the cleanliness and product quality of the workshop.
â–¶ Temperature and humidity control
Constant temperature and humidity: Lithium battery cleanrooms need to maintain stable temperature and humidity. Generally speaking, the temperature in the workshop should be maintained between 20-25 ℃, with fluctuations not exceeding ± 2 ℃; The humidity should be adjusted according to the humidity requirements of different workshops, and the fluctuation range should not exceed ± 5%.
â–¶ Anti static measures
Anti static treatment: Equipment and personnel in the workshop should be grounded to eliminate the generation of static charges. Anti static materials and equipment such as anti-static workbenches and gloves should be used in the workshop. The workshop should be equipped with professional anti-static detection equipment to regularly detect and monitor static electricity in the workshop. 
â–¶ Safety facilities
Complete safety facilities: The workshop should be equipped with complete safety facilities, such as fire extinguishers, smoke alarms, emergency evacuation routes, etc. The layout and equipment of the workshop should comply with safety production standards to avoid cross infection and contamination. Establish a sound safety management system and emergency plan, strengthen employee safety education and training, and ensure the safety and controllability of the production process.

What regulatory and safety standards are applicable?
International standard
  ISO 14644 standards: This is an internationally recognized standard for clean rooms and related controlled environments. It defines the requirements for different levels of cleanrooms and related equipment, including cleanliness, pressure differentials, airflow patterns, and monitoring methods. ISO 14644-1 specifically analyzes the standards for cleanrooms and related controlled environments, covering cleanroom classification and cleanliness levels, air cleanliness testing methods, microbial contamination control, personnel and material access control, equipment and facility requirements, as well as documentation and records.
Regional and national standards
  Federal Standard 209E: This is a cleanroom standard defined by the United States, which defines the classification, monitoring requirements, and validation methods of cleanrooms, with a focus on their performance and effectiveness.
  ASTM E1226 standard: developed by the American Society for Testing and Materials (ASTM), providing specific guidelines for measuring and monitoring cleanroom cleanliness, defining airborne particle counters and monitoring methods.
  The Chinese national standard GB/T 16282 is applicable to the design, construction, operation, and monitoring of cleanrooms, based on the ISO 14644 standard, but with specific requirements specific to China's unique conditions.
Other relevant standards
  BS 5295 standard: applicable to the design and operation of clean rooms in the UK, providing requirements consistent with ISO 14644 standard, with a focus on the airtightness and airflow management of clean rooms.

Solution for Manufacturing Electric Vehicle Batteries
1. Cleanrooms and drying rooms for battery production and development
â–¶ The functions of clean room
  Control the impact of environmental factors on batteries
During the battery production process, a clean room can effectively control dust particles in the air and reduce pollution to the battery manufacturing process. For example, in the production of lithium batteries, it is important to prevent dust particles from entering the battery materials and affecting battery performance.
  Cleanrooms can effectively control temperature and humidity. By using air conditioning systems and humidity control equipment, a constant temperature and humidity condition can be maintained to ensure stable performance and quality of the battery. Because controlling humidity and temperature is crucial in battery production, as temperature fluctuations affects battery chemical reactions and humidity changes leads to short circuits or corrosion.
  It reduces the impact of particles in the air on battery performance, and also reduce the interference of static electricity on battery production through measures such as electrostatic elimination devices, ensuring the safety and stability of batteries.
Prevent pollution and comply with regulatory requirements.
  Some harmful substances and chemicals may have a negative impact on the performance and safety of batteries. Cleanrooms can filter and purify the air to reduce the presence of harmful substances and protect the quality and safety of batteries.
  The battery production industry has a series of regulations and standards that have clear requirements for the cleanliness and safety of the production environment. Cleanrooms help battery production companies comply with these regulations and standards, ensuring compliance and legal operations.

â–¶ Key points for planning and construction of clean rooms
Cleanroom layout
  For clean rooms of new energy batteries, the area should meet the experimental requirements, including space for placing test benches, equipment, and devices, as well as activity areas for staff. The production area should be divided according to the production process, such as raw material preparation area, electrode preparation area, cell assembly area, cell testing area, and finished product inspection area. In addition, the width of the aisle should not be less than 1.5 meters, and the overall floor height of the clean room should consider factors such as equipment installation, maintenance, and cleaning, generally not less than 3.5 meters.
Selection of decoration materials
  The decoration materials for clean rooms should generally be dust-free, odorless, corrosion-resistant, and easy to clean, to ensure the cleanliness and aesthetics of the clean room. Environmental friendly materials such as antibacterial and mildew resistant wall and floor materials should be preferred, and the quality and durability of materials should be emphasized to avoid a decrease in cleanliness due to material quality problems.
Equipment and facility considerations
  When selecting equipment and facilities, full consideration should be given to testing needs and methods. Appropriate equipment is beneficial for improving the accuracy and efficiency of detection, such as battery testers, voltage and current meters, cyclic voltammetry meters, etc. In addition, targeted equipment such as air purifiers, clean rooms, low-temperature refrigerators, etc. need to be used for laboratory environmental facilities, and it is necessary to ensure that all metal structures, equipment, and conductive components are connected to the ground wire to introduce static charges into the ground and reduce the possibility of accumulation and discharge.
Exhaust design
  In terms of exhaust, the chemical and capacitive power cabinet areas usually come with exhaust equipment, such as fans. These fans can exhaust hot air through ducts to the ceiling, and then open air intake louvers from the side walls or ceiling to allow the heat dissipation part to circulate naturally. it avoids excessive positive or negative pressure, which can affect the air parameters of adjacent rooms.

â–¶ Technical highlights of clean rooms
Accurate temperature and humidity control
  Adopting advanced sensors and control systems to ensure temperature fluctuations within ± 0.5℃ and humidity fluctuations within ± 3% RH, ensuring production stability.
HEPA filtration system
  The multi-stage filtration device effectively removes dust, particles, and harmful gases from the air, achieving ISO7 cleanliness standard.
Intelligent management
  Internet technology enables remote monitoring and intelligent control, data visualization platform makes management more convenient, and fault warning function ensures production safety.

â–¶The relevant situation of drying rooms in battery production and development
 The function of the drying room
  The drying room is mainly used to prevent moisture from affecting batteries (such as lithium batteries). The moisture content in lithium battery materials is one of the main sources of moisture in the battery cells, and the higher the environmental humidity, the easier it is for the battery materials to absorb moisture from the air. The drying room can control the humidity at a lower level to avoid adverse effects of moisture on battery performance, such as reducing battery life, performance (charging capacity), and safety issues (including the possibility of explosion) caused by moisture.
Humidity requirements for drying room
  The moisture content in the lithium battery processing area should be less than (-) 35 ° C (-31℉) dew point and/or moisture content of 0.14g/kg of dry air. The room temperature should be maintained at the recommended level of approximately 25℃(77 ℉) with a tolerance of+/(-) 2℃(36 ℉). The dew point range is (-) 35℃(-31℉) to (-) 45 ℃(-49℉) (0.14 to 0.04g/kg). The ventilation rate in the production workshop should be more than 25 times per hour, and the minimum fresh air volume for maintaining positive indoor pressure and ventilation should be maintained.
  Key points for selecting dehumidification equipment for drying rooms
  When selecting dehumidification equipment, multiple factors need to be considered, such as the airtightness of the workshop enclosure, the airtightness of the air ducts, the number of personnel, and the control methods of the workshop.

Dedicated testing room and controlled environment
  According to different facilities, clean room facilities for power lithium batteries are distributed in different areas to meet unique processing, testing, curing, drying, or storage requirements.
Aging room equipment
  Aging room, also known as high-temperature aging room or burner room, is a device specifically designed to simulate high-temperature environments for aging testing of materials or products. The equipment is mainly used to evaluate the heat resistance and stability of materials or products conditions under high temperature, and is widely used in industries such as electronics, electrical appliances, automotive, aerospace, etc. It helps manufacturers and research institutions evaluate and improve product quality and reliability by simulating high-temperature environments
Customized walk-in temperature box
  A walk-in temperature chamber is a special environmental simulation device. It is also known as a walk-in constant temperature and humidity test room or a walk-in environmental test chamber. Compared with typical high and low temperature chambers, the size is relatively larger, so large that testers can enter the testing room, that's why it is called "walk-in". It achieves a temperature accuracy of ± 0.5℃and an even higher operating range of -40℃to 85℃.

Classification and format of clean rooms for electric vehicle batteries

  The workshop cleanliness of automotive grade power lithium battery cleanrooms is usually between ISO8 and ISO7 (ISO8 cleanrooms have a particle count of less than 3520000 particles per m³≥0.5 microns, equivalent to FedStd. 209E's class 100000, while ISO7 cleanrooms have a particle count of l≤ 352000 particles m³≥0.5 microns, equivalent to FedStd. 209E's class 10000). However, in some key process stages (such as coating, rolling, cutting, liquid injection, and air inlet stages), high-grade cleanrooms ISO5-ISO6 (Airkey patented products) will be set up to ensure the production yield of products.

Fan filter unit(FFU)
  For areas or equipment that require high cleanliness, the top mounted FFU filtration device provides a constant laminar airflow from top to bottom. EC/DC variable speed fan allows dynamic adjustment of speed output and can provide ultra-high air volume and output ultra-high air speed
Airkey's high airflow FFU equipment, specially developed for power lithium battery production environments, is your top choice!

Cleanroom pressure control and HVAC
  Cleanroom pressure control 
  Prevent pollution
  To prevent external pollutants from entering the clean room and increasing indoor cleanliness, it is required to maintain indoor pressure higher than external pressure, that is, a positive pressure cleanroom. The pressure difference between clean rooms of different levels and between clean and non clean areas shall not be less than 5Pa, and the pressure difference between clean areas and outdoors shall not be less than 10Pa. It effectively prevent the clean room from being contaminated or contaminated by neighboring rooms while maintaining a certain pressure difference indoors.
  Meet the production process requirements
  In modern cleanroom technology, the cleanliness needs to always meet the requirements of the production process. The pressure difference control in the clean room is a key point. Through reasonable pressure control, the environment in the clean room can be ensured to meet production standards, thereby ensuring product quality and production progress.
  AIRKEY modular hard wall components provide the highest degree of customization and ensure precise and efficient air pressure control flexibility for precise systems
  Electric vehicle battery facilities require a combination of positive and negative pressure sealing systems to achieve the coordinated operation of hazardous and non hazardous materials. A positive pressure cleanroom maintains a higher air pressure than the surrounding area to prevent dirtier, low-pressure air flowing into the cleanroom from the external environment. Therefore, the modular hard wall series products of AIRKEY are a very suitable product!

HVAC system
  Control air volume regulation
  The relationship between supply & return air volume and exhaust air volume: Cleanrooms establish and maintain pressure differences by adjusting supply air volume, return air volume and exhaust air volume. The basic principle is that the supply air is greater than the return air, exhaust air, and leakage air volume to maintain positive pressure. For example, when the supply air volume continues to exceed the return air and exhaust air volume, the indoor pressure will be higher than the external pressure, thus creating a positive pressure environment.

Utilize air filtration equipment
  The functions of HEPA filters: In cleanroom applications such as biological purification engineering, high-efficiency air (HEPA) filters in HVAC systems also have an indirect impact on pressure control. HEPA filters can remove extremely fine particles and microorganisms from the air, which helps maintain the cleanliness of the clean room air, reduce changes in ventilation resistance caused by dust and other factors, and stabilize the pressure environment of the clean room. Moreover, in the circulating clean room, the air passes through the HEPA fan filtration device over and over again, making the air cleaner and extending the service life of the HEPA fan filtration device. It is beneficial for the stable operation of the entire HVAC system to maintain pressure stability.
  AIRKEY customize a suitable HVAC system for you based on your workshop and building environment, while meeting the requirements of the production environment and achieving as much green, environmentally friendly, and energy-saving as possible!
  AIRKEY has 20 years of customized production experience in air shower rooms, and provide unique designs and solutions for large-sized cargo shower rooms and special function shower rooms in the lithium battery industry. If you have any questions or needs, please contact us!