How Do Batteries Store Energy?

In daily life, we often come into contact with batteries, such as the electric vehicles we ride, there are e-bike batteries. When it comes to seemingly simple questions about batteries, one has to dive into the intricacies. Defining a battery requires more nuance. A battery is a variety of chemical and mechanical devices that operate under different physical principles. In this context, a battery is a device capable of storing energy in chemical form and converting the stored chemical energy into electrical energy when needed. The cylindrical battery we are most familiar with exemplifies this definition. However, it is important to realize that no battery can actually store electrical energy; Instead, they accumulate energy in other forms. Even within this particular definition, a large number of chemical combinations exist that can store electrical energy, a list that is too exhaustive to be detailed in this concise overview.

Describes the types of chemical batteries

Two basic categories of chemical energy storage batteries are worth exploring: rechargeable batteries, called secondary batteries, and non-rechargeable batteries, called primary batteries. In terms of energy storage and discharge, they have the same function; This difference depends on the ability of multiple charging and discharging sequences.

Grasp the difference: galvanic and battery

Before delving into the answer to this question, it is necessary to distinguish between galvanic and previously defined batteries. The primary cell constitutes the basic electrochemical storage unit. In contrast, a battery consists of at least one, but possibly multiple, interconnected galvanic cells. Given that the battery coordinates the actual storage and discharge process, our focus remains on its operation.

Interpreting the anatomy of electrochemical cells

At the core of an electrochemical cell are two electrodes separated by a certain distance. The electrolyte, an ionic liquid that promotes electrical conductivity, occupies the space between these electrodes. The anode, an electrode, allows electrons to flow outward. The cathode, another electrode, receives these electrons. Energy is present in specific compounds that make up the anode, cathode and electrolyte, such as zinc, copper and SO4.

Guided discharge process

Once the battery reaches a charged state, either through charging or production, the cumulative result of the chemical reaction between the anode and cathode appears as a discharge. The anode undergoes an oxidation reaction: During a discharge, two or more ions from the electrolyte combine with the anode, forming a compound and releasing electrons. At the same time, the cathode underwent a reduction reaction. In this process, components such as ions, cathode materials and free electrons are mixed together to form compounds.

Electronic Dance: A Symphony of Harmony

In simple terms, the chemical reaction of the anode releases electrons, while the chemical reaction of the cathode absorbs electrons. These concurrent reactions begin when the electrolyte and an external circuit provide an electrical path, connecting the anode and cathode. The electrons released from the anode pass through the external electrical connection and undergo a chemical reaction at the cathode, which fills the battery with energy. This discharge can continue until one or both electrodes exhaust their reagents in their respective reactions. In primary cells, this indicates that they are useful; In secondary cells, it signals the need to recharge. The charging process of a secondary battery follows the opposite discharge trajectory. An external DC power supply feeds electrons into the anode and takes them out of the cathode. This forces the chemical reaction to resume until the battery is charged again.

untangle

The above elucidation provides a simplified description of how electrochemical energy is stored in a battery, converted to electrical energy during discharge, and recovered during secondary battery charging. However, many electrochemical and thermal processes unfold in tandem. For most of the actual battery components encapsulated into batteries, fully characterizing all of these processes proved insurmountable. This concise summary of the main reactions thus barely scratches the surface of the complex processes at work. However, it proves the basic principle of coordinating this dynamic interaction.