SEPARATORS “There are certainly challenges involved in melding the physical properties of the PE separator with the chemical properties of the rubber separator. We have expertise in combining these two types of materials together”— Jean-Luc Koch, Microporous cycle and sealed battery technologies, to feed into the development of EFB separators. “Our work on lead acid battery separators can also benefit from developments in lithium ion battery separators,” says Whear. Separators for both battery technologies are made the same way, by wet processing, even though the shape and the formula is different, the equipment is the same. “They have different challenges but LEAD ACID COMPARISON IN START-STOP: EFB VERSUS AGM BATTERIES
Technical / Commercial Needs
Source: Daramic
RESULTS OF PREVENTING WATER LOSS
Definitions: SoC – State of Charge SoH – State of Health BMS – Battery Management System Source: Daramic
64 • Batteries International • Winter 2015/2016
Enhanced Flooded Battery
VRLA-AGM
some also overlap. We know that the trend in lithium ion battery separators is to go thinner and this will happen in lead acid also. So the Daramic business can learn from the practice and experience of the Celgard business,” says Whear. Daramic also benefits from the Asahi Kasei acquisition, with its expertise in raw materials science, such as fibre and resins and additives, but also in terms of providing access to advanced computer modelling, enabling new formulations to be experimentally simulated before the prototyping stage. Meanwhile Microporous is looking to motive applications, where hybrid polyethylene-rubber separators are used. Jean-Luc Koch, head of Microporous won’t talk too much about what this entails, except to say: “There are certainly challenges involved in melding the physical properties of the PE separator with the chemical properties of the rubber separator. We have expertise in combining these two types of materials together.” Compared with the lithium ion industry developments in the lead acid industry are more incremental. Potentially, enhancements to separators might ultimately allow for improved use of lead or a reduction, reducing weight and size, even if only comparably slightly, as lead acid batteries do not have the densities of lithium ion. “The demands placed on the battery are more complex. Automotive battery manufacturers must meet multiple requirements in their product at the same time, some require more plate surface area, which a very low resistance separator will help, while others require a certain amount of active material, which a very low resistance separator will not have an impact on,” says John Timmons, vice president of technology at Microporous. A big challenge is the automotive industry itself, where the pressure on OEMs’ supply chain partners is to deliver products that meet demand for increased electrification of vehicles, where projections for trends over the next decade see lead acid and advanced lead acid batteries dominating, but be-
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