Chaowei Power develops graphene technology to improve lead battery performance

Chinese battery manufacturer Chaowei Power launched a new version of its Black Gold battery for electric bikes at the end of February — a lead-acid battery that uses the nanomaterial graphene as an additive.

“We have shortened the current road length from 312mm to 150mm between cells inside the battery, thus the battery resistance is greatly reduced by 52%,” chief scientist Dai Guiping told BESB. “Performance of the battery in low temperature operations has been greatly improved.

“The capacity of the battery has also increased with additional active materials, and the terminal design has been optimized.”

Chaowei makes lithium and lead acid automotive batteries under the Chilwee brand. Its Black Gold high-energy VRLA series was launched almost exactly a year ago, on February 29, 2016, when it first applied graphene technology to a commercial, mass-produced rechargeable lead battery.

Following its structural update, the firm says its total discharge time is 90 minutes compared with 65 minutes for a standard lead battery, and it offers 610 cycles at 100% depth of discharge as opposed to 400.

“Graphene plays an important role in improving performance for lead acid and lithium ion batteries,” said Dai. “For example, in lead acid batteries, the use of graphene is envisaged as offering benefits in its high intrinsic electrical conductivity and being extremely lightweight, chemically inert and flexible yet with a large surface area.

“The presence of graphene in the electrodes improves the electrical conductivity between the particles of the active mass through preventing thickening and the growth of large lead sulfate particles. This feature is attributed to the formation of a stable and conductive matrix that enables homogeneous delivery and distribution of current to all parts of the active material.

“By enabling a uniform current distribution, and subsequently well distributed electrochemical redox reactions throughout the electrode matrix, we arrested the formation of too large lead sulfate particles,” he said.

“The addition of graphene is also considered able to increase both the mechanical stability and electrical integrity of the electrodes and to induce uniform changes in the active mass during charge-discharge cycling.”