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What Does the Inside of a Car Battery Look Like?

Reviewed by

Richard McCuistian, ASE Certified Master Automobile Technician

Technical Reviewer at CarParts.com

Written by CarParts.com Research Team - Updated on August 19th, 2025

Reading Time: < 1 minute

Summary

Removing the battery lid exposes six cells that are separated by a plastic wall.
LED plate straps are welded together to connect each cell, slightly towering over each plastic wall.
Each plate strap is connected to several LED plates, which are formed into grid-type structures to maximize the surface area.

car battery diagram showing inside — Car battery diagram showing what’s inside | Image Source: Richard McCuistian

A: Removing the battery lid exposes six cells that are separated by a plastic wall. Each of these cells generates approximately 2.1V of DC, bringing up the total voltage to around 12.6V. LED plate straps are welded together to connect each cell, slightly towering over each plastic wall.

Each plate strap is connected to several LED plates, which are formed into grid-type structures to maximize the surface area. These grids are then covered with a paste of lead oxide, which acts as a sponge that absorbs electrolyte fluid.

Electrolyte fluid is the term used to describe the acid solution in the battery, which is made up of 36% sulfuric acid and 64% water.

About The Authors

Written By

CarParts.com Research Team

Automotive and Tech Writers

The CarParts.com Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by CarParts.com's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Reviewed By

Richard McCuistian

Technical Reviewer at CarParts.com

Richard McCuistian has worked for nearly 50 years in the automotive field as a professional technician, an instructor, and a freelance automotive writer for Motor Age, ACtion magazine, Power Stroke Registry, and others. Richard is ASE certified for more than 30 years in 10 categories, including L1 Advanced Engine Performance and Light Vehicle Diesel.

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