Causal tree analysis for quality control of the lead acid battery manufacturing process

Abstract

Summary The aim of this paper is the quality control of the manufactured lead acid battery by using the causal and fault tree analysis. The causal tree allows the description of the correlations between the battery degradation modes and their causes during the manufacturing process. The causes of the degradation are the low quality of lead oxide, low grid oxidation, bad adjustment of temperature and density, wrong dosage of additives, irregular dosage of lead calcium or lead antimony, and existence of impurities. These causes facilitate the appearance of the degradation modes during the battery use such as the stratification of electrolyte, poor cohesion of active mass, hard sulfating, and corrosion of electrodes. The consequences of the several causes during the manufacturing process on the parameters of the electrical equivalent circuit of the battery are discussed to elaborate the fault tree and analyze the new manufactured lead acid battery quality. In fact, a diagnostic method based on the analysis of the electrical equivalent circuit parameters' variation is developed. This diagnostic method allows the determination of the rated capacity loss and the degradation depth of new manufactured lead acid battery. Therefore, this study allows identifying the causes leading to manufacturing defects and their impact on the available rated capacity of the battery to judge its quality.

Directional DC Charge-Transfer Resistance on an Electrode–Electrolyte Interface in an AC Nyquist Curve on Lead-Acid Battery

“…In Figure 4, the black solid line is the output of transient voltage responses in FPLC DCequ simulation under AC-input. The black dashed line cancels the steady-state DC voltage response from the black solid line, and the DC component is exactly equal to Equation (9). The blue dotted line filters the steady-state AC fundamental voltage response out of the black solid line by Equation (10), and the blue dotted line is very close to the black dashed line, which has a little distortion from higher harmonics.…”

“…Similarly, an equivalent DC negative response 〈v Dis 〉 is on electrode-electrolyte interfaces, as Equation (8). Then equivalent DC response V DC on electrode-electrolyte interfaces is the sum of 〈v Cha 〉 and 〈v Dis 〉, as Equation (9). Steady-state DC static voltage responses are shown in FPLCDCequ simulation under DC-input [2,3,20], but do not exist in experiments under AC-input.…”

“…Elements in a circuit, fitting for EIS, are simplified from governing equations [7,8] in lead-acid battery and have clear physical/electrochemical meanings; so, they are the first principle and basis of classic threshold-based BMS design. Charge-transfer resistance and double-layer capacitance are related to non-cohesion of active mass of electrodes; contacting resistances represent the existence of stratification and corrosion of electrodes; nonlinear diffusion impedances characterize sulfating of electrodes [4,9]. Multi-scale SoC/SoH judgment based on EIS is an extension of threshold-based management [10,11]; circuits elements are nonlinearly influenced by various factors, e.g., SoC, charging or discharging, superimposed DC current [12]; other form signals, such as short step response, can take place of sinusoidal excitation to demonstrate dominant aging mechanisms on battery capacity [8].…”