Consumers have become more aware of the potential lithium ion battery safety issues following a number of high-profile incidents, not the least of which is the grounding of the new Boeing 787 Dreamliner.
Solutions are being found, however. One of the latest is the launch of a new type of ceramic battery separator â€“ the SYMMETRIX NC2020 â€“ by Porous Power Technologies (PPT), which is based in Plymouth Meeting, PA.
Automotive Industries (AI) asked Michael Pender, Managing Director of PPT, how SYMMETRIX NC2020 improves battery safety.
Pender: It starts during the manufacture of the cell itself where several unique features of NC2020 (conformability, wettability, hydrophobicity, temperature tolerance) help minimize manufacturing faults. Reducing cell failure triggers such as voids, dry spots, moisture content, and shrinkage contributes to higher cell manufacturing yields and lower in-service failure rates. Once the cell is in use it is not uncommon for dendrites to form between electrodes, ultimately causing shorts. The resulting localized heat can cause traditional materials to shrink, causing a hard short. Even when the damage is relatively minor it still degrades cell safety, cycle life and performance. The nature of the NC 2020 pore structure makes it less likely for dendrites to penetrate. But, if one were to bridge, then the temperature tolerance of our polymers significantly reduces localized shrinkage and continued propagation of the incursion. This same problem can be triggered by external causes, such as damage to battery packs by foreign objects. In third party validated testing, NC2020 extends the time between damage and cell failure, and significantly lowers the temperatures involved.
AI: Why is this important?
Pender: We’re not talking about a tool not working. We’re talking about people feeling (and being) safer as they put themselves and their families inside vehicles using new technologies. From a practical standpoint larger cells, higher voltages, and higher current densities could increase the risks if mitigating innovations such as our microporous ceramic membranes are not utilized.
AI: Can the technology be used to replace separators in existing battery pack designs?
Pender: Indeed. Customer tests have shown that NC2020 performs favorably in comparison to its competitor products, improving the life cycle of existing pack designs while also delivering safety benefits. But, Porous Power’s value proposition is also about enabling new technologies. The dimensional stability, temperature and oxidation resistance that are core to our products allow customers to move forward with higher performance chemistries, higher voltages, broader temperature ranges, and other functionalities that current separator offerings can’t tolerate.
AI: How cost competitive is the technology?
Pender: Based on customer feedback we are very competitive against alternatives from other suppliers. This is particularly so when you consider that, in many cases, customers have to perform additional steps such as coating ceramic layers onto their existing products in order to get acceptable performance. Customers want to make cells and packs â€“ not separators. On another note, the intellectual property landscape is getting increasingly crowded. PPT has a unique IP portfolio that allows us to make and sell our products without having to worry about these issues