This numerical study outlines the design and optimization of parallel microfluidic chips for future use in a membrane-free microflow battery. The system operates by exploiting the potential difference between electrodes and ion diffusion generated by fluids of differing concentrations flowing through a straight microchannel, thereby eliminating the need for a physical membrane. A key challenge in such systems is understanding the effect of the channel geometry and velocity on the resulting electrical output. To address this, we employed the Taguchi Design of Experiment methodology, reducing the experimental workload from 64 full factorial runs to just 16 strategically selected trials. Using simulation data and image processing techniques, we systematically analyzed the mixing behavior of the two electrolytes under various geometric and flow configurations. A vertical line profile was extracted at the channel outlet, and pixel intensity values along this line were used to compute the mixing index. This quantitative approach enabled us to identify the optimal design and flow conditions that enhance the mixing efficiency could possibly influence battery performance. Based on these findings, we are developing two parallel microchannels with diffusion layers that could be used for membrane-free microflow battery system in the future applications and potentially turned into a power generator for wearable electronics.