Astro Chemical Improves Performance Properties and Efficiency in Conductive Adhesive for Energy Storage Application
THE CHALLENGE
Astro Chemical was approached by an original equipment manufacturer (“OEM”) customer who was having trouble developing a conductive adhesive for use in the production of large, grid-scale energy storage batteries. The OEM was using an adhesive derived from known chemistries used in the battery industry, which was adequate for initial engineering development and proof of concept. When their design progressed to pilot production and UL testing, the adhesive experienced failure in both conductivity and adhesion when exposed to the highly acidic aqueous environment of the battery.
Under examination, it was found that the bond was compromised not by the breakdown of the adhesion, but by the corrosive attack of the acidic aqueous environment. The design required complete coverage of the adhesive throughout the bond area in order to prevent attack of the metallic substrate by the acidic media. However, the application technique and the properties of the metallic surface created sporadic voids and weak spots in the adhesive-substrate interface which caused corrosion, localized loss of conductivity and loss of adhesion to the metallic substrate. The overall effect significantly compromised the efficiency and service life of the battery.
The challenges were multifaceted and included 1) formulation of a conductive adhesive with improved resistance to the acidic aqueous media, 2) identification of an improved application process, and 3) characterization of the metallic substrate surface properties.
THE SOLUTION
Astro Chemical’s Lab collaborated directly with the OEM’s engineering and technical staff to address each of these challenges and develop a wholistic solution. The key aspects of the approach were as follows:
- Product Development: Through an iterative process involving screening and ladder study testing, Astro’s development chemists identified a formulation that not only improved and sustained conductivity results but also resisted the permeation of the acidic aqueous media between the conductive adhesive and metallic substrate. Despite the unique challenges, Astro Chemical’s expertise in formulating electrically conductive, non-metallic adhesive chemistries played a crucial role in identifying a timely solution for the customer.
- Substrate Preparation: Astro’s lab characterized the surface properties of the incoming metallic substrate, focusing on surface tension and cleanliness; demonstrating the criticality of these properties to overall performance of the adhesive. As a result of this analysis, the customer implemented in-process quantification testing and added a precleaning step to their new manufacturing processes. Further, collaboration with the metallic substrate provider ensured that the proper surface conditions were met upon receipt.
- Application Process: Astro’s development team explored various application processes and collaborated with equipment manufacturers to support an upgrade to the customer’s process. On-site technical assistance was provided during the application evaluation, including laboratory tests for adhesion and conductivity. Astro then worked closely with the customer to identify and implement an effective drying process, considering both equipment specifications and process requirements. Through iterative drying testing, we demonstrated the crucial role of the drying process in optimizing the application process and resulting adhesion strength.
RESULTS
By collaborating with the OEM’s technical staff, Astro Chemical was able to provide formulatory, testing, and consulting solutions allowing the customer to move forward, meeting their critical deadline. Together, we were able to implement a reliable, high-speed manufacturing process that integrated an improved conductive adhesive. Enhancements to surface preparation, application, and drying processes resulted in consistency and performance exceeding the customer’s service life requirements, ultimately achieving UL Certification, validating a targeted 20-year lifespan.
Several years later the OEM has successfully launched the battery design and continues to observe benefits including:
- Reduced Down Time: Optimizing the entire process and the critical materials allowed for higher through-put and reduced production loss due to line stoppage.
- Increased Quality Improvements: Astro Chemical provided the customer a conductive adhesive with much improved bond strength and chemical resistance leading to increased lifecycle reliability.
- Reduced Total Costs: By adopting a wholistic approach to a multifaceted challenge, Astro Chemical helped the OEM optimize for value by minimizing product waste, streamlining process inefficiencies, and increasing product quality through improved performance.
