I've discovered something which I feel is significant:
Ultralife, in their Jun 96 10-K, describes their battery as:
"The Company's advanced rechargeable battery is based on lithium-ion solid-polymer technology. The battery is composed of a lithiated manganese dioxide cathode, a carbon anode and a solid-polymer electrolyte, all of which are flexible. The battery's construction provides for the high performance characteristics of lithium-based batteries, particularly high energy density, while eliminating the use of lithium metal and a liquid electrolyte. By eliminating the use of lithium metal, the Company's battery is not subject to the formation of dendritic lithium metal structures upon multiple rechargings, which the Company believes will result in superior cycle life for its battery. Additionally, use of a flexible solid-polymer electrolyte, rather than a liquid electrolyte, reduces the battery's overall weight and volume, and allows for increased flexibility in conforming batteries to the variety of shapes and sizes required by various OEMs...."
Lithium Technology, in their Dec 96 10-K, describes their battery as:
"The Company's lithium metal polymer rechargeable battery design is based upon an integrated approach employing a patented and proprietary cell construction using high performance fiber webs, and a flexible solid polymer electrolyte. The Company's lithium metal technology incorporates a lithium alloy foil anode and a composite vanadium oxide cathode. The Company's lithium-ion polymer technology uses fiber webs for both the graphite anode and lithiated cobalt oxide cathode. One advantage of this approach is the use of a solid polymer electrolyte rather than the traditional liquid electrolyte technology. Unlike the liquid electrolyte used in most batteries, the Company's battery electrolyte is a thin, flat, solid plastic which reduces weight and volume, and improves safety...."
Hitachi/Maxell, in the EE Times newsarticle, describes their battery as:
techweb.com
"The anode and cathode are cobalt lithium and carbon, respectively. The flexibility in the shape comes from its polymer electrolyte. Hitachi Maxell engineers used three types of monomer and polymerized them into an electrolyte polymer. The battery has no liquid electrolyte, eliminating the need for a heavy and bulky metal container; instead, it can be sealed with a thin film."
Valence, however, in their Mar 96 10-K, describes their battery this way:
"The Company's research prototype battery is composed of flexible solid plastic matrixes which are formed into an anode matrix layer, a separator matrix layer, and a cathode matrix layer. The anode matrix layer contains a carbon material capable of holding lithium ions. The separator matrix layer is composed of only the plastic matrix. The cathode matrix layer contains metal oxide material that stores lithium ions. After the matrix layers are formed and cut into the desired shape, they are laminated together to form a cell. The cell is interconnected to other like cells to form a battery. Plasticizer material in the cell matrix layers is then extracted, leaving voids throughout the matrix layers of the cells. Finally, liquid electrolyte is absorbed into the cell, filling the voids left by the extracted filler material, activating the cells and the battery.
In conventional liquid electrolyte batteries, the liquid electrolyte that permeates the battery's components is sealed in a metal container to assure its contact with all the internal components of the battery. The liquid electrolyte in the Company's battery is contained within the solid polymer matrix that forms the anode, separator and cathode matrix layers. Because the liquid electrolyte is contained in the solid polymer matrix and is therefore in intimate contact with anode and cathode materials, it does not need to be held under pressure, and the battery can be packaged in a thin flexible plastic/foil packaging material, instead of a metal container, which reduces weight and volume."
Upon comparison, it seems to me that Ultralife, Lithium Tech, and Hitachi/Maxell are incorporating a solid polymer (with no liquid) as the electrolyte in their battery. Valence, however, seems to be using polymers between the anode and cathode layer to contain a liquid electrolyte.
All this time, I thought the physical makeup of each company's batteries were similar, but it now appears to me that they are not. I also don't understand why there are differences in the physical makeup of Valence and Ultralife's batteries since both are Bellcore licencees.
Do these differences have any significant ramifications to the long-term outlook for any of these companies? Or am I trying to get too much scientific information from non-scientific documents???
Anyone have any comments??? |
