How much do you know about battery terminology?

How much do you know about battery terminology?

As a leading company specializing in the production of batteries, we are well aware of the important role that batteries play in modern society. In order to deepen your understanding of batteries, we have compiled some professional battery terms, hoping to help you. Let's take a deeper look!

Battery: A power supply device consisting of one or more electrochemical cells with external connections, used to power electrical devices.

Battery cell: refers to a single component containing positive and negative electrodes and other necessary electrochemical and structural components. A battery cell is an independent energy conversion device that delivers electrical energy to an external circuit through a controlled internal chemical process. This conversion involves ion transfer between electrodes with different potentials.

Primary battery: Also known as a disposable battery, this type of battery can only be discharged once. After all the internal chemicals have reacted, it can no longer provide electrical energy or store external power supply. It cannot be used after being fully discharged.

Secondary battery: Also known as a rechargeable battery, it is a battery that provides electrical energy through a reversible electrochemical process. This means that the chemical energy converted into electrical energy can be recovered by applying a current in the opposite direction to the flow direction when the battery is in use. The current flowing in the battery during use is called the discharge current, and the current that recovers the chemical energy is called the charging current. Secondary batteries have the ability to store chemical energy when not in use. For example: lithium-ion batteries, nickel-cadmium batteries, nickel-metal hydride batteries, etc.

Battery module: A battery cell assembly in series, parallel or series-parallel configuration, with only one pair of positive and negative output terminals. The battery module is the smallest repeating component in a battery pack.

Battery pack: It is composed of multiple battery modules connected in parallel or in series, and assembled with components such as housing, management and protection devices to meet specific application requirements.

Battery Management System (BMS): A system that intelligently manages batteries to manage and maintain each battery cell, monitor battery status, and prevent overcharging and over-discharging to extend battery life. Common functions of BMS include power measurement, communication, state of charge (SoC) estimation, state of health (SoH) estimation, abnormal warning, abnormal protection, equalization, temperature measurement, battery measurement, etc. For details, please refer to the article "What is BMS for LiFePO4 Battery Packs?".

Battery model: Taking cylindrical lithium-ion batteries as an example, it is usually represented by five digits, the first two digits represent the battery diameter, the second two digits represent the battery height, and the fifth digit represents that the battery shape is cylindrical. For example, the IFR26650 battery of plb refers to a cylindrical battery with a diameter of 26mm and a height of 65mm.

Calendar aging: Calendar aging is the irreversible capacity loss of a battery during storage. In other words, it is the performance degradation caused by battery storage.

C-Rate: C is used to represent the ratio of charge and discharge current. For example: a battery discharged at a discharge rate of nC will provide its rated capacity in 1/n of the operating time. For example, for a 2500mAh battery, 1C represents 2500mA (1 times 2500mAh). It discharges at a rate of 1C and it takes 1 hour to fully discharge. Similarly, discharging at a rate of 0.5C (1250mA) will take 2 hours to fully discharge. For details, please refer to the article "What is a high-rate battery?".

Cycle life: A cycle refers to the period of time from the start of one charge/discharge to the start of the next charge/discharge. Cycle life refers to the maximum number of times a battery can maintain stable performance and capacity without degradation during charging and discharging.

Depth of Discharge (DoD): Depth of discharge is the ratio of the amount of discharge to the total amount of charge during the use of the battery. DoD = 100% means that the battery is exhausted, and DoD = 0% means that the battery is fully charged. The DoD term is usually used to describe the cycle life of the battery.

Positive electrode: The electrode with higher potential in the primary battery or electrolytic cell. When the battery is discharged, it acts as the cathode due to the reduction reaction in the electrolyte. When the battery is charged, it acts as the anode due to the oxidation reaction in the electrolyte.

Negative electrode: The electrode with lower potential in the primary battery or electrolytic cell. During the discharge of the battery, it acts as the anode due to the oxidation reaction in the electrolyte. During the charging of the battery, it acts as the cathode due to the reduction reaction in the electrolyte.

Electrolyte: Electrolyte refers to a compound that can generate ions and conduct electricity between the positive and negative electrodes of the battery in a solution or molten state.

SEI (Solid Electrolyte Interface): SEI is a passivation layer formed on the surface of the lithium-ion negative electrode material after the electrolyte decomposes. The quality of SEI has a crucial impact on the performance of lithium-ion batteries.

Self-discharge: Self-discharge is the loss of battery capacity caused by a spontaneous reaction inside the battery when it is not connected to an external circuit.

State of Charge (SoC): The state of charge is also called the remaining capacity. It is used to reflect the remaining capacity of the battery. It is usually expressed as a percentage, ranging from 0-1. SoC=0 means the battery is fully discharged, and SoC=1 means the battery is fully charged.

State of Health (SoH): SoH is defined as the ratio of the battery state to the ideal state, expressed as a percentage. Generally, the SoH of a new battery is 100%, which will decrease with time and use.

Trickle Charge: Trickle charge uses a low-rate charging current to compensate for the capacity loss caused by self-discharge after the battery is fully charged, thereby maintaining a state close to full charge.

I believe this overview will give you a better understanding of batteries. I hope these terms will help you make an informed decision when choosing and using batteries.