Expander is an additive for negative plate of lead acid battery that is use to improve battery performance and cycle life by increasing the contact area and preventing from passivation while discharge process.

This additive should be added to negative paste during negative paste mixing and the usage percentage depends on the application of lead acid battery.

There are different formulations for expanders but all of them are containing 3 parts that each of them plays its own role in lead acid battery:

• Lignosulfonate
• Baso4
• Carbon black.

The amount of each part should be the optimize value to improve both performance and cycle life at same time.

The end user can choose the type of each component and the amount of each part to improve the charge acceptance, start ability and performance of lead acid battery.