Glossary of LiFePO4 Battery

Abuse

The act of using a battery not in accordance with the manufacturer’s or battery chemistry’s requirements.

Activation

The final step in making the electrochemically active components in a cell functional to generate the desired electrical energy.

Active Material

Electrode material that undergoes an electrochemical reaction to store or release electrical energy during cell charging and discharging.

Ambient Temperature

Usually refers to the temperature of the battery surface.

Ampere Hours (Ah)

Unit expressing the capacity of a battery or cell. Ampere Hours are the product of a battery’s or cell’s discharge rate and discharge time.

Anode

Usually refers to the electrode where oxidation occurs during an electrochemical reaction. An anode is positive when charging and becomes negative when discharging.

All Solid State Rechargeable Lithium Battery

The battery cell contains only solid electrolyte, and does not contain any liquid electrolyte, liquid solvent, liquid additive rechargeable lithium battery.

Battery

Two or more cells connected together in series or parallel. “Battery” is the common term for a single cell.

BESS

Battery energy storage system (also known as ESS).

BMS

Battery Management System is An electronic management system that connects batteries and equipment. The main functions include real-time monitoring of battery physical parameters, battery state estimation, online diagnosis and early warning, charge, discharge, pre-charge control, balance management, thermal management, etc.

Balance

 levelling the voltage parameters and State of Charge (SOC) of the different cells within a battery pack. 

C-Rate

 “C “= Capacity. Unit by which charge and discharge times are scaled. At 1C, the battery charges and discharges at a current that is at par with the marked Ah.

Capacity

The amount of energy a cell or battery can store. Expressed in Ampere-hours.

Rated Capacity

The manufacturer indicates the discharge capacity of the cell or battery measured under specified conditions.

Nominal Capacity

The nominal value of the rated capacity.

Residual Capacity

The capacity left in a cell or battery after use under specified conditions, such as discharge or storage.

Discharge Capacity

The output capacity of a cell or battery measured under specified conditions.

Recovery Capacity

The capacity that can be output when the battery is left at a specified temperature for a specified time, fully charged after discharge, and discharged again.

Cathode

Usually refers to the electrode where the reduction reaction takes place. During discharge, the cathode is positive; during charge, it is reversed and becomes negative.

Cell

The cell is the smallest unit of LiFePO4 battery module. The nominal voltage is 3.2V.

Prismatic Cell

A cell in the shape of a parallelepiped with its faces at right angles.

Cylindrical Cell

A cell whose total height is equal to or greater than its diameter.

Pouch Cell

Packaged into a flexible, heat-sealable foiled pouch.

Power Cell

Cell designed for maximum current delivery, high rate of discharge.

Energy Cell

Cell designed for maximum capacity and longer cycle life.

Charge

The process of using an external power source to increase the voltage and capacity of a battery, at which point electrical energy is converted into chemical energy.

Charge Retention

The ratio of the output capacity of the battery to the rated capacity without recharging when the battery is left at a specified temperature for a specified time is usually expressed as a percentage.

Constant Current Charge (CC Charge)

The process of charging a rechargeable cell or battery at a constant current.

Trickle Charge

A charging method that allows the call or battery to maintain a continuous, long-time, low current charging state under regulation.

Full Charge

The cell or battery is considered fully charged when it has reached the maximum capacity specified by the manufacturer.

Floating Charge

The battery is continuously subjected to constant voltage charging with low current for a long time.

Overcharge

A full cell or battery continues to charge.

Charge Equalization

Bring all the cells in a battery or string to the same state of charge.

Charge Curve

The voltage-time curve was recorded during battery charging.

Current

Directional movement of charge.

Discharge Current

The output current when the battery discharged.

Short-Circuit Current

The maximum current a battery can deliver to an external circuit with zero resistance or reduces the battery voltage to near zero volts.

Coulomb

Unit of electric charge. One coulomb (1C)equals one ampere-second(1As).

Cut-off Voltage

The load voltage of the battery at the end of charge and discharge.

Closed Circuit Voltage

The voltage between the two terminals when the battery is discharged.

Cycle Life

The cell or battery life is considered terminated if the cell or battery capacity is lower than the specified capacity value for three consecutive charge and discharge cycles. At this time, the last time that the number of charge and discharge cycles reaches or exceeds the specified capacity value is the cycle life of the cell or battery.

Discharge

The process by which a battery outputs the generated electrical energy to an external circuit.

Depth of Discharge(DoD)

The percentage of the capacity released by the cell or battery to its rated capacity. For example, the capacity of a cell with a capacity of 10Ah becomes 2Ah after discharge, which can be called 80% DOD.

Self-Discharge

The phenomenon in which the energy of a cell or battery is not discharged into the external circuit but is lost in some other way.

Overdischarge

Forced discharge when the battery is fully discharged.

Discharge Curve

The voltage-time curve was recorded during battery discharging.

Discharge Current

The output current of a battery when it is discharged.

Echelon Use

refers to conducting a necessary inspection, classification, disassembly, and battery repair of used lithium-ion electric car batteries (including the New Old Stock and defective items) and consistency screening so they can be reused in other fields.

Energy Density

The ratio of a battery’s energy to volume or weight expressed in watt-hours per cubic inch/mm or pound/Kg. For example, a cell weighing 325g has a nominal voltage of 3.2V and a capacity of 10Ah; its energy density is 98Wh/Kg.

Electrolyte

A liquid or solid substance that contains mobile ions and is ionically conductive.

Electromotive Force

The difference between the battery’s positive and negative balancing potential.

Equalization

The voltage of each cell in the battery is adjusted as much as possible.

Formation

The process of charging the battery for the first time, activating the active material of the LFP battery, and forming a stable solid electrolyte interfacial film (SEI film).

Grouping

In order to ensure the consistency of cells or batteries, the process of grouping cells or batteries according to their capacity.

Impedance

the resistive value of a battery to an AC current expressed in ohms (Ω ). Generally measured at 1KHz at full charge.

Internal Resistance

when the battery is working is the resistance of the current flowing through the battery.

Lithium Primary Battery

non-rechargeable battery.

Lithium-Ion Battery

A battery that uses lithium ions as conductive ions to move between the positive and negative electrodes and realize charging and discharging through the mutual conversion of chemical energy and electrical energy.

Liquid Rechargeable Lithium Battery

A lithium-ion battery containing only liquid electrolyte.

Lithium Dendrite

Dendritic metal lithium formed when lithium ions are reduced during the charging of a lithium-ion battery.

Load Dump

A BMS disconnects during charging, which disconnects the battery.

Nominal Voltage

The nominal value of rated voltage.

Negative Terminal

A conductive part that facilitates the connection of an external circuit to the negative pole of the battery.

Parallel Connection

Two or more cells or batteries are connected with the positive electrode, and the negative electrode is connected with the negative electrode.

Positive Terminal

A conductive part that facilitates the connection of an external circuit to the positive pole of the battery,

Protection Circuit Board

A printed circuit board (PCB) with an integrated circuit (IC) that protects the battery is generally used to prevent battery overcharge, overdischarge, overcurrent, short circuit, ultra-high temperature charge, discharge, etc.

Plate

Electrodes of batteries are composed of current collectors, active materials, binders, conductive agents, etc.

Negative Plate

Usually refers to an electrode sheet with high potential that undergoes a reduction reaction of active species during discharge.

Positive Plate

Usually refers to an electrode sheet with high potential that undergoes a reduction reaction of active species during discharge.

Rechargeable Lithium Battery

Lithium-ion and lithium metal batteries are collectively referred to as lithium batteries (also known as rechargeable and secondary lithium batteries).

Rechargeable Lithium Metal Battery

A lithium battery containing lithium metal on the negative side of the battery。

Separator

A battery component made of an ion-permeable material that prevents contact between oppositely polarized electrode sheets within the battery.

Series Connection

Two or more cells or batteries with positive and negative electrodes connected.

State of Charge(SoC)

The ratio of the remaining capacity of the battery after it has been used for a period of time or left unused for a long time to its fully charged capacity is usually expressed as a percentage.

State of Function (SoF)

Reflects battery readiness that verifies capacity, current delivery, voltage, SoC, self-discharge and more; measured in %. (Capacity, current delivery and SoC are most basic.)

State of Health (SoH)

Reflects battery performance that verifies capacity, current delivery, voltage and self-discharge, measured in %. SoH excludes SoC.

Tab

A metal conductor that connects the battery’s internal electrode tabs to the terminals.

Thermal Runaway

A critical condition in a battery is caused by the rate of heat generation exceeding its ability to dissipate heat, resulting in a continuous rise in temperature, which in turn leads to the destruction of the battery.

Voltage

Voltage is the potential difference between the two ends of a cell or battery and can be likened to the water pressure at both ends of a water pipe.

Open-Circuit Voltage

The voltage when the charging and discharging current of the cell or battery is zero.

Overvoltage

A condition in which the battery voltage exceeds the manufacturer’s rating or a specified condition.

End of Charge Voltage

The voltage reached by the cell or battery at the end of charge while the charger is still attached.

Working Voltage

The voltage between the two terminals when the battery is discharged at the operating current.

VPC

Volts per cell.

Uniformity

The similarity of the important parameters of all cells in the battery.

UN 38.3

Safety norms for shipping battery products.

Watt

Unit of power: ampere(A) times volt (V) equals watts(W).

Watt-Hour

Unit of electrical energy equivalent to the power consumption of one watt for one hour. Multiplying a battery voltage (V) by the rated capacity(Ah) gives the battery energy in Wh.

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