Manufacturing Innovation for a Competitive US Battery Industry

In the Winter 2009 Insights, this cover article reviewed the pending EWI workshop focused on assembly technologies for battery applications. On February 18-19, 2009 over 70 participants from industry, government, and research organizations met at EWI to discuss the current state of battery assembly, identify technology needs and gaps, and lay the groundwork to explore potential solutions. These experts represented a broad range of industries including battery manufacturers, equipment suppliers, automotive OEMs, consumer electronics companies, and medical device developers. The workshop included industry needs discussions, technical presentations, and advanced technology demonstrations.

It was concluded that improved assembly methods are needed to achieve cost, performance, and reliability objectives. Many specific technology gaps facing battery manufacturers were also identified, which can be summarized into four broad categories:

• Joining of new material combinations
• Robust, high-speed assembly processes
• Quality control for small, high-speed welds
• Life-cycle performance prediction

Joining of New Material Combinations
New electrode materials under development will require the use of coating processes that are new to this industry. Development of processes tailored to these materials would be a major step towards more cost effective production of batteries. Joining dissimilar material combinations also poses a challenge. Batteries and battery packs may require the joining of various combinations of copper, aluminum, nickel-plated steel, glass, ceramics, and polymers. Differences in thermal properties and adverse chemical interactions can impair joint quality. In many cases, industry lacks the data necessary to make informed decisions when joining specific dissimilar material combinations.

Robust, High-Speed Assembly Processes
The new markets for rechargeable batteries will require highly reliable production methods, since even one bad cell may compromise the function of an entire battery pack. Robust hermetic sealing methods are needed to prevent intrusion from water and air to ensure reliable performance during years of operation. For some material combinations, reliable sealing methods have yet to be developed. Additionally, the small, precise nature of the components poses significant challenges for automated assembly. Improved methods are needed to consistently achieve necessary bond quality at high production rates.

Quality Control Tools for Small-Scale, High-Speed Welds
Since a single joint failure may compromise the performance of the entire system, the industry needs ways to quickly check the quality of individual assembly joints. For many industries, process monitoring and nondestructive evaluation (NDE) technologies are employed to ensure products consistently meet minimum performance standards. Monitoring technology involves statistical analysis of assembly process data to determine whether processes are in control. NDE technologies are used to inspect the quality of completed joints. Unfortunately, conventional NDE and monitoring technologies are not generally suitable for very small scale welds and short duration welding processes, so new approaches must be developed.

Life-Cycle Performance Prediction
New battery designs lack large bodies of historical field data to assess life-cycle performance when subjected to various loading (e.g., vibration, impact) and environmental (e.g., temperature and humidity variations) conditions. Laboratory-scale testing in combination with computer modeling could provide a means to assess the implications of assembly processes on reliability. Models targeted to the specific scale and materials used by the industry will help with both battery design and assembly process optimization.

Call to Action - What's Next?
The importance of manufacturing innovation to the battery industry was highlighted during the Battery Assembly Technology Workshop with the identification of four key technology gaps. A major manufacturing technology research effort is needed to fill these gaps and create a competitive advantage for America’s domestic battery manufacturers. The scope of these challenges is beyond the capabilities of any one manufacturer to develop a comprehensive solution. In the current economic climate, commercial entities are not in a position to fully fund the high-risk research necessary for breakthrough manufacturing innovation. A public/private partnership, involving government, battery manufacturers, suppliers, and integrators will provide the opportunity to amortize the investment in next generation battery assembly technology across all the products and manufacturers that can benefit. The federal government’s commitment to advancing the competitiveness of the US battery industry is visible in the $2 billion Advanced Battery Grants in the American Recovery and Reinvestment Act of 2009 (ARRA).

A Joint Industry Program (JIP), organized across the range of companies and industries where new battery technologies are relevant would be an effective vehicle to leverage government and industry funding for collaborative R&D. For a battery assembly technology JIP to be completed quickly and efficiently, the scope of the research needs to be focused on specific high-impact areas identified by the JIP partners. Once results are achieved for the core manufacturing approaches, they can be fine-tuned to the industry-, company-or product-specific applications throughout the supply chain, further broadening and deepening the impact of the program.

EWI is currently compiling the industry inputs and working with industry participants to formulate an initial technical plan for the JIP. For additional information, please contact Candice Mehmetli at cmehmetl@ewi.org or call 614.270.1121; or David Speth at dspeth@ewi.org or call 614.688.5162.