In the last decade or so, the technology in electric vehicles has advanced significantly including increased battery range, faster charging, wireless charging, battery management, battery weight reduction, power and efficiency of the electric motor, and many others. There are two main components in the electric motor, namely, rotor and stator. Hairpins are critical part of a stator. They are made of pure copper. One of the important processes in the fabrication of a stator is connecting/welding the individual hairpin. In this paper, a brief description of hairpin manufacturing based on the published articles and the results from more recent investigation, particularly the welding aspect is provided.

Biochar produced from bio-waste of cellulose-extracted kenaf residue was utilized as a conductive additive for electrodes in electric double-layer capacitors (EDLCs). The EDLC cells were assembled using electrodes with varying mixing ratios of kenaf-derived carbon (KC), and hydrocarbons-derived carbon black (CB) which had been industrially utilized as the conductive additive. Although the sole use of KC could not provide a sufficient electronic conduction in the EDLC electrodes, the combinational use of KC and CB attained a formation of stable conductive path therein. The energy density of the EDLC cell utilizing electrodes composed of KC and CB at a mixing ratio of 50:50 in mass under the use of 8 M KOH electrolytic solution and the cell voltage range of 0−1.0 V was found to be approximately equivalent to that of electrodes composed solely of CB, particularly at power densities below 100 W kg⁻¹. Through the application of KC to the conductive electrode additive, we discovered new potential uses for kenaf residue.