Battery fundamentals — a storage battery is classified as an electrochemical device because it primarily:

Introduction / Context:
Automotive batteries convert chemical energy into electrical energy during discharge and reverse the process during charging. Recognizing the basis for this classification clarifies why temperature, state of charge, and electrolyte composition influence performance and life.

Given Data / Assumptions:

• Conventional lead–acid or modern lithium-ion chemistries are considered.
• Electrolyte and electrode materials participate in redox reactions.
• Mechanical configuration (curved/flat plates) is not the defining feature.

Concept / Approach:

Electrochemical devices rely on oxidation-reduction reactions at electrodes immersed in an electrolyte, generating an electromotive force. In a lead–acid battery, lead dioxide and sponge lead react with sulfuric acid to produce lead sulfate and water during discharge, releasing electrical energy to the circuit. Charging reverses these reactions. This chemical-to-electrical energy conversion is the essence of “electrochemical.”

Step-by-Step Solution:

Verification / Alternative check:

Open-circuit voltage, internal resistance, and capacity are functions of state of charge and temperature, predictable from electrochemical principles (Nernst equation, reaction kinetics).

Why Other Options Are Wrong:

Makes chemicals by mechanical means — irrelevant; mechanical mixing does not define batteries.
Curved plates — a design choice (e.g., spiral cells) but not the reason for the classification.
No electrolyte — most rechargeable chemistries use electrolytes (liquid, gel, or solid); absence would preclude ion transport.

Common Pitfalls:

Confusing electrochemical cells with electrostatic devices (capacitors); assuming plate shape determines performance more than chemistry and construction.

Final Answer:

uses chemical action to provide electricity