Dry rooms needed for manufacturing lithium based batteries are not simply modified “clean rooms” or large “environmental chambers”. John Pinho, President of NeoTech explains.
Manufacturing lithium‑ion batteries is a complicated technical process that has many challenges – not the least of which is the requirement for all processing of the lithium electrodes for the battery cells to be done under very low humidity conditions – typically below 1% RH (- 35°C to -40°C dew point) and must also be a low particulate environment. These important requirements demand that the dry room be hermetically sealed from the outside environment.
On the other hand, typical clean rooms (like those used in the semiconductor industry) are actually designed to leak, so that the positive internal pressure prevents any particle intrusion into the space. As such, typical clean room environments are only controlled to humidity levels around 40% RH, which is many more times as humid as a typical dry room. To better control the humidity in the cell processing areas, industrial scale dry rooms were developed that allowed manufacturing to take place in an almost absolute dry environment.
A handful of companies became very specialized in dry room design, materials technology and the supporting dehumidification equipment, controls and air distribution systems. As with any developing technology there were mistakes made early on and there was a steep learning curve in defining and then executing the design details.
Depending on the battery chemistry used, elemental lithium can be present during manufacturing and can react violently when exposed to even very small amounts of moisture (so low that it requires special instrumentation to even measure it), the consequences of not managing moisture can be devastating – including the potential to destroy the facility and its contents. When working with lithium, mistakes can be costly, and several of the early manufacturing plants were badly damaged or destroyed by violent lithium reactions caused from loss of moisture control in the working space.
More prevalent than the factory “meltdowns” were battery quality issues caused by dry rooms and HVAC systems that could not consistently maintain the precise environmental conditions that are required to assure a high quality battery manufacturing process. Even slight variations in the humidity levels during the manufacturing process can affect the cycle life of the lithium cells and the maximum storage capacity of the cells over time.
Early dry room providers learned how to design and install a manufacturing environment that was safe, reliable and consistent. However, these early dry room HVAC systems, though small, consumed prodigious amounts of energy as the tradeoff to maintain the very critical environmental conditions.
With time and experience dry room providers have been able to reduce energy consumption by over 30% with new proprietary dehumidification system, materials, components, options for regeneration of the desiccant, and much more energy efficient designs. This becomes increasingly important operating cost factor in high volume plants because the dry rooms are growing to very large sizes between 30,000 to over 150,000 square feet (2800 to 14,000 square metres).
The demand for lithium battery manufacturing facilities has experienced a tenfold increase during the last eighteen months as a result of the convergence of several factors; fossil fuel price pressures, renewable energy growth, electric and hybrid autos and the proliferation of military field electronics.
Availability of stimulus funding from the U.S. government has also prompted a number of battery manufacturing start-ups and joint ventures all launching at nearly the same time, competing for this new and expanding market sector. This has resulted in the need for building many new, large and high-volume lithium‑ion battery manufacturing facilities faced with increased time and cost pressures to get these facilities operating quickly and efficiently to take advantage of the funding timelines.
Due to the surge in demand for production of large, high volume facilities, some new players have entered the dry room marketplace that have abundant experience in semiconductor or medical clean rooms, environmental rooms or HVAC systems but have little or no direct dry room design and construction experience. Since the dry room is a large up-front investment for the owner of these factories, there seems to be a growing tendency for some new suppliers to offer their dry room products at significantly lower costs, in order to win contracts.
Some of these suppliers have reallocated the resources that used to design semiconductor clean rooms (which is a declining market) to try to penetrate the growing dry room market. They face a steep learning curve, similar to what experienced dry room providers faced when they entered the market 20+ years ago.
However, unlike their predecessors, mistakes made now would have a much more profound negative impact as the size of the planned facilities are significantly larger and the amount of product affected by a single event is far greater.
In addition, some battery companies are looking to buy out the dry room as individual components from various suppliers rather than an integrated solution. This can become a problem when there are performance issues with the dry room as there is no clear path to ownership of the problem(s).
Mistakes in the design or installation of the dry room can create major problems for the owners of the facilities over time, including poor battery quality, reduced capacity, excessive downtime, energy inefficiency and even potential catastrophic losses. The more experienced dry room suppliers have avoided projects where time constraints, cost pressure or other facility design issues could cause the design and construction of the dry rooms to be compromised, and thus would not allow them to guarantee the dry room performance over the long term.
The costs for mistakes and poor performance are much greater now because the lithium‑ion battery manufacturing plants being built today are very large with very high levels of production. These are not pilot projects but true high volume manufacturing facilities that are semi or fully automated where even a slight problem with the dry room performance will have a significant impact on the quality and quantity of batteries manufactured.
For high volume lithium‑ion battery manufacturers, the dry room is likely one of the most expensive ‘process equipment’ the battery manufacturer will ever purchase. It needs to be able to meet the demanding specifications for today’s process technology and easily be supplemented for future needs.
Therefore a number of important and critical requirements need to be considered when selecting supplier(s) to deliver your successful dry room project:
• Start with an experienced supplier who has the ability to design and build a large, high volume dry room(s) to meet your required specifications. The prime supplier would also be able to help you to understand the cost -benefit options for incremental performance points.
• Insure that the dry room supplier guarantees the performance of the entire dry room as a system, including the walls, ceilings, floor coatings, doors, HVAC, lighting, controls and all external penetrations.
• Select materials for floors, doors, walls and ceiling construction that will integrate well and will also satisfy the local authority having jurisdiction (AHJ) approval as well as local codes, fire rating, look and feel, etc.
• Build in a level of redundancy with a practical approach to its application. For example, some amount of redundancy is necessary to allow performance of routine maintenance on the dehumidification systems, particularly if the operations are 24/7 or if there is a significant loss of power that could impact a large volume of production. Separating the dehumidification system from the airborne particle filtration system might be a more effective approach that allows redundancy and a simpler path to upgrade for future needs.
• Instrumentation systems are just as critical and should integrate all the control and monitoring functions of your dry room into a single package that is reliable, accurate and provides important information to the operators of the dry room.
• Maximizing energy efficiency will significantly reduce the long-term operating costs of the dry room and your entire facility. Dry-room providers should be required to provide a detailed energy analysis for the dry room(s) as part of their package as well as offer equipment options, such as multi-mode HVAC system controls.
• Consider constructability, logistics planning and supplier’s track record with difficult or unique installations. The successful vendor should be able to demonstrate to the owner via shop drawings, submittals, project schedules, risk management plans and experienced on-site installers that have “been there, done that” before. Field installation is not the time to “figure out how to do it”.
• Develop a long-term preventative maintenance plan that addresses the critical nature of the dry room systems and will ensure continued functionality at design conditions for its entire life.
Additionally, several critical parameters need to be defined by the owner up front when specifying a dry room:
• Process requirements: temperature, dew point, particles, exhaust, chemicals, ESD, future needs.
• People load and shift timing: access/egress, material, equipment movement, level of automation, shift times/breaks.
• Machine loads: heat, exhaust, chemicals, noise levels, automation, penetrations for utilities.
• Energy consumption: HVAC, lighting, utility costs, variety of available utilities (electricity, gas, chilled water, steam).
• Recovery requirements after an event: redundancy, backup power, chilled water.
• Controls integration (dehumidifier, refrigeration, air handling, and building automation).
• Cost of malfunction or downtime: training, preventive maintenance, field service.
• Building integrity: occupancy class, floor condition, ceiling loads, existing utilities, grounding.
• External environment: climate, local codes, seismic zone, access to various utility providers.
• Managing change: tighter specs, lower operating expenses, modular design.
• Integrated design and delivery: including spec validation, commissioning, formal acceptance validation, training, field service and services after the sale.
In summary, high volume lithium‑ion battery manufacturing requires one of the most critically controlled process environments in order to be successful. The learning curve is very steep and mistakes can be costly in terms of product quality, productivity and energy costs, and can result in severe damage to the equipment and injuries to workers. A wise course is to work with dry room providers who will include all of the necessary services and will also provide the support, training and track record of long-term success in not only the-design, but the full integration, delivery and ongoing support of your largest equipment investment.
John Pinho is President of NeoTech, LLC a consulting firm specializing in helping clients with new technology transfer, start ups and ramp to high volume manufacturing. He has over 30 years experience in all aspects of high tech industrial, commercial and government projects across the globe. Prior work experience includes Global Director of Facilities for A123 Systems; Strategic Facility Design Manager for Intel Corporation. In addition he has held various process engineering, operations, quality and design roles at Acoustic Imaging, Digital Equipment Corporation, General instruments, GTE and National Semiconductor. Contact via email at jpinho@azneotech.com
Scientific Climate Systems is a design/build firm that specializes in dry rooms/clean rooms for the Lithium Battery industry. www.dryrooms.com
