PDF Publication Title:
Text from PDF Page: 023
The most significant stack-design aspect of the 20kWh battery is the use of flat- plate chlorine electrodes in the unit cells. The 20kWh battery remains the only large-scale battery utilizing this concept. Due to the economics and waste asso ciated with machined-electrode technology, flat-plate electrodes will probably be the basis of future cell designs. Consequently, the experience gained with the 20kWh battery system will be invaluable in providing for this transition. The secondary purpose of this assignment was to upgrade the electrochemical perfor mance of the battery stack. The goal was to provide a delivered energy in excess of 19kWh at an energy efficiency greater than 65%. 20kWh STACK DEVELOPMENT The primary obstacles which prevented the achievement of the electrochemical goals of the 20kWh battery were considered to be dendrites and cell imbalance. The early appearance of dendrites precluded the battery from being charged to full capacity, and reduced coulombic efficiency. Cell imbalance refers to the variation in the voltage time profiles of the individual unit cells during discharge. This also reduced coulombic efficiency. In order to resolve these difficulties, and to increase an understanding of the important factors in stack design, the following approach was taken. First, the causes of the dendrites and cell imbalance were determined by parasitic current measurements, and by visual observation of the zinc morphology. Then various experi mental modifications were performed on four cells (10R, 9R, 8R, and 7R). The re sults of these modifications and of the parasitic current measurements provided the basis for modifications to the entire battery stack. Cell Modification Experiments The zinc morphologies were examined on four unit cells (10R, 9R, 8R, and 7R) . Figure 23-1 illustrates the placement of these cells in the stack. These cells were disassembled from the stack after the battery was charged well beyond the appearance of dendrites. The dendrites were found to be heaviest at the bottom of the plates near the CI2 bus (chlorine electrode bus) side. They also ran across the bottom of the plates, and vertically along the Cl^ bus side. It further was found that the top and bottom corners of the plates near the Zn bus (zinc electrode bus) side were bared of zinc. The zinc plates then were peeled off and weighed. The results can be seen in Table 23-1. The pattern of decreasing zinc deposition was 23-2PDF Image | Development of the Zinc-Chlorine Battery for Utility
PDF Search Title:
Development of the Zinc-Chlorine Battery for UtilityOriginal File Name Searched:
6302789.pdfDIY PDF Search: Google It | Yahoo | Bing
Salgenx Redox Flow Battery Technology: Power up your energy storage game with Salgenx Salt Water Battery. With its advanced technology, the flow battery provides reliable, scalable, and sustainable energy storage for utility-scale projects. Upgrade to a Salgenx flow battery today and take control of your energy future.
| CONTACT TEL: 608-238-6001 Email: greg@salgenx.com | RSS | AMP |