The use of a Polymat material to reduce the effects of sulphation damage occurring in negative electrodes due to the partial state of charge capacity cycling of lead acid batteries

• Published in: Journal of power sources 2012-02, Vol.200, p.102-107
• Main Authors: Snyders, C., Ferg, E.E., van Dyl, T.
• Format: Article
• Language: English
• Subjects: Adhesion; Applied sciences; Blinds; Charge; Charge materials; Cycles; Damage; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Electrodes; Exact sciences and technology; Partial capacity cycling; Pb-electrode; Polymat; Sulfation; Venetian-blind effect
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2011.10.087

► The use of a polyester non-woven material (Polymat) to reduce the effect of sulphation damage on the negative electrodes of Pb-acid batteries due to high rate partial capacity cycling (HRPSoCCC). ► The Polymat does not necessary reduce sulphation due to HRPSoCCC but reduces the physical damage due to irreversible active material damage also known as the “Venetian Blinds” effect. ► The study showed little or no difference in the cells electrochemical performance that were made with or without Polymat. ► The study also showed that cells with the Polymat that showed failure due to HRPSoCCC could partially recover their low rate discharge capacity if subjected to a simple pulse recharge sequence. A conventional lead acid cell that is exposed to a high rate partial state of charge capacity cycling (HRPSoCCC) would show the results of irreversible negative electrode damage due to excessive PbSO 4 formation that can be visually seen by the “Venetian Blinds” effect of the active material. This displays the loss of adhesion of the active material with the electrode's grids thereby making large sections of the material ineffective and reducing the cells useful capacity during high current applications. The use of a commercial lightweight polyester non-woven material that was referred to as “Polymat” was placed on both sides of the negative electrode, has demonstrated a better physical adhesion of the active material thereby maintaining the active material's physical integrity. This however does not reduce the sulphation effect due to the HRPSoCCC test but only reduces the physical damage due to the irreversible active material “Venetian Blinds” effect. The study looked at the effect the Polymat has on the battery's cold cranking ability (CCA) at −18 °C, the HRPSoCCC and its active material utilization. Typical flooded nominal 8 Ah test cells were assembled with 3 positive and 2 negative plates with and without Polymat. The study showed that there was little or no difference of cells made with the Polymat on the CCA and HRPSoCCC capabilities when compared to cells without the Polymat, with significant improvement in active material's adhesion and integrity to the grid wire. Partial recovery of the cell's discharge capacity made with the Polymat could be achieved after the “failed” cells were subjected to a simple pulse recharge sequence.