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Understanding Batteries: Terms You Need to Know
When comparing and purchasing batteries for your application, it is important to understand the basics of battery ratings and terminology to ensure you are using the right type and quantity to meet your project energy goals. This blog is designed to introduce you to battery terminology.
1.Deep Cycle Battery Chemistry Types
Lead Acid Batteries:
• Flooded Battery (FLA)
• Sealed Gel Battery (SLA)
• Absorbent Glass Mat Battery (AGM)
Lead Acid Batteries Invented in 1860 Lead Acid Batteries are heavier, have lower capacity, and have a shorter cycle life than Lithium Batteries.
Lithium Batteries:
Contains Cobalt
• Nickel Manganese Cobalt (NMC)
• Lithium Cobalt Oxide (LCO)
• Nickel Cobalt Aluminum Oxide (NCA)
Contains No Cobalt
• Lithium Iron Phosphate (LiFePO4 or LFP)
Battery chemistry with non-cobalt-based chemistries such as LiFePO4 is more stable and less prone to thermal runaway and fire. BSL uses LiFePO4 batteries throughout its product line.
2.Battery Parts
Electrodes
There are two electrodes in a battery: the anode and the cathode. Anodes are negative electrodes, where oxidation occurs during discharge. Cathodes, however, are positive electrodes where reduction occurs.
Electrolyte
Electrolytes allow ions to move between electrodes by acting as a medium. During battery storage and release, it facilitates chemical reactions.
Anode
Anodes are electrodes that oxidize during discharge cycles. Electric current is generated by the release of electrons and ions into the electrolyte.
Cathode
Cathodes are electrodes where reduction occurs during discharge. An electric circuit is completed when it accepts electrons and ions from the electrolyte.
Separator
An anode-cathode separator prevents electrical short circuits while allowing ions to pass through.
Terminal
A terminal allows electrical current to be transferred from a battery to an external device or charging source.
Casing
Insulation and structural integrity are provided by the casing, which houses and protects the battery’s internal components.
Cell
The basic component of a battery, the lead-acid battery has a nominal voltage of 2V and the LiFePO4 has a nominal voltage of 3.2V.
• Battery reversal
Over-discharging a battery causes its polarity to reverse.
• Battery mismatch
Batteries in a battery pack have inconsistent capacities, voltages, or internal resistance values.
• Primary battery
There is no possibility of recharging and reusing a battery or battery pack that has only been discharged once. Batteries made from alkaline manganese zinc, for example.
• Secondary battery
Due to its reversible nature, it can be charged and discharged multiple times. Batteries made of lead-acid, for example.
• Cylindrical battery:
A cylindrical container is used to store the positive and negative plates. Batteries such as AAs and 18650s are examples.
• Prismatic battery:
There is no rolling of the positive and negative plates. They are stacked instead.
• Pouch battery
This product is packaged in a foil bag that can be heat sealed.
• Power battery
Battery with a high discharge rate and maximum current delivery.
• Energy battery
The capacity of a battery is maximized. Longer cycle li
3.Battery performance section
Capacity
Indicates the amount of energy provided by a cell or battery pack. Measured in ampere-hours.
• Usable capacity
The discharge time (ampere-hours) of a battery calculated from the battery’s charge, discharge, temperature, and cutoff voltage.
• Rated capacity (“C”)
Manufacturer’s data on the discharge capacity that can be produced at a specific discharge and temperature.
• Capacity fade
The reduction in the available capacity of a battery due to charge and discharge. For example, the available capacity of a mobile phone battery drops from 100% to 80% after 1 year.
• Capacity drift
If the discharge rate exceeds the specified C rate, a capacity correction is required
Voltage
The potential difference between the positive and negative terminals of a battery. It determines the force with which electrons flow through a circuit. It is usually expressed in volts (V).
Current
Current represents the flow of charge in a circuit and is measured in amperes (A). It represents the rate at which current moves through a circuit.
Energy density
Energy density represents the amount of energy a battery can store per unit. It is expressed in watt-hours per liter (Wh/L) or per kilogram (Wh/kg). Batteries with higher energy density have greater energy storage capabilities.
Power density
Power density refers to the amount of power a battery can deliver per unit volume or mass. It is expressed in watts per liter (W/L) or kilograms (W/kg). The higher the power density, the greater the power.
Cycle life
Cycle life refers to the number of charge and discharge cycles a battery can go through before its capacity decreases significantly. The longer the cycle life, the longer its durability and useful life.
Self-discharge rate
The rate at which a battery loses its charge over time when not in use.
Efficiency
Efficiency measures how effectively a battery converts stored energy into usable electrical energy. The higher the efficiency, the less energy is lost during charging and discharging.
Internal Resistance
Internal resistance represents the resistance to the flow of current within the battery. Batteries with low internal resistance can deliver current more efficiently.
C Rating
The C rating represents the discharge rate of a battery relative to its capacity. For example, a battery with a 1C rating can deliver its entire capacity in one hour. The higher the C rating, the faster the discharge rate.
Ampere (ampere)
A unit of measurement for electric current that represents the rate at which charge flows
Amp-Hour
The current (ampere) multiplied by the hour, for capacity.
One amp of current for one hour equals one amp-hour.
A B-LFP-50 is a 50 amp-hour battery, which can be calculated by dividing 50 amp-hours by the operating time of the load you are powering at 100% discharge. For example, if you are running a load at 10 amps, 50 amp-hours will power the load for 5 hours.
Watts
A unit of power that represents the rate at which work or energy is transferred. It is calculated by multiplying the voltage by the current.
Watt-hour
This unit of energy represents the amount of energy consumed or generated by a device rated at 1 watt when operating for one hour. It measures the energy consumption of an electronic device over a specific period of time.
4.Charging and discharging
Charge
Supply power to the battery to restore its capacity.
Discharge
Release the power stored in the battery to power external devices.
Overcharge
Charge the battery beyond the recommended capacity or voltage. It is easy to shorten the battery life, heat up, and even cause thermal runaway.
Deep discharge
When the battery is discharged to insufficient voltage, deep discharge occurs. For example, the standard voltage of LFP is 3.2V, and the cut-off discharge is 2.5V. When it is lower than 2.5V, continued discharge will cause irreversible damage.
Trickle charge
Trickle charge is a low-current charging method used to make up for the capacity loss caused by self-discharge of the battery after it is fully charged.
Fast charge
Charge quickly in a short time.
Float charge
Charge with a constant voltage and a small current to prevent battery self-discharge, and at the same time increase the depth of charge.
Battery Management System (BMS)
Used to control and protect battery operation, including charging, discharging, and temperature regulation. BMS ensures that the performance, safety, and life of the battery are running in the best condition.
BSLBATT’s batteries all have built-in BMS, which can effectively improve battery performance and extend battery life. BMS provides protections for: overvoltage, undervoltage, overcurrent, overheating, short circuit and battery imbalance.
5.Battery Connection
Series connection
Series connection means connecting the batteries end to end, with the positive terminal of one battery connected to the negative terminal of the next battery, thereby increasing the total voltage while keeping the capacity constant. For example, it is used for forklift batteries and golf cart batteries.
Parallel connection
Parallel connection means connecting the batteries side by side, with the positive terminals connected to the positive terminals and the negative terminals connected to the negative terminals. This method ensures that the voltage remains constant while increasing the total capacity. For example, it is used for industrial and commercial Energy Storage System（ESS）.
Series-parallel connection
Combines series and parallel connections to achieve the voltage and capacity of the application.
6.Routine maintenance and safety
Proper maintenance measures are essential to extend battery life and prevent accidents:
Thermal runaway
Thermal runaway is when the battery temperature rises rapidly due to internal reactions or external factors. It may cause fire or explosion. All BSL battery series are equipped with thermal sensors to protect the BMS from thermal runaway.
Overheating
It means that the battery is operated at a temperature higher than the recommended temperature. High temperature will lead to reduced battery capacity, shortened life and increased probability of thermal runaway.
Short circuit
When the positive terminal of the battery is directly connected to the negative terminal, bypassing the intended circuit, a short circuit occurs, and a large amount of current discharge will damage the battery and surrounding components.
Venting
Lithium batteries are equipped with pressure relief valves for safety. Releasing gases or built-up pressure when overcharged or otherwise protects the battery.
Battery Degradation
Battery degradation is the gradual decrease in its capacity and performance over time. Many factors can cause battery degradation, including usage patterns, temperature exposure, and charge/discharge cycles. Regular battery maintenance, proper charging, and avoiding extreme operating conditions can extend battery life and minimize battery degradation.
Cell Balancing
Cell balancing ensures that each cell in a multi-cell battery, such as lithium-ion, has a balanced charge level. To prevent overcharging or over-discharging of a specific cell, balancing prevents unbalanced capacity and performance degradation across the entire battery pack. Balance can be maintained by actively monitoring and controlling voltage as the battery pack is charged and discharged.
State of Charge (SOC)
A measure of the amount of charge remaining in a battery, expressed as a percentage. Over-discharging damages the battery, so monitoring SOC prevents over-discharge and ensures the battery’s usability.
State of Health (SOH)
A battery is defined by its state of health and performance capabilities compared to its original specifications. Degradation is calculated based on capacity loss, internal resistance increase, and overall degradation. Evaluate SOH to determine its remaining life and reliability, and maintain or replace the battery when necessary.
Understanding battery terminology can effectively use and maintain batteries in a variety of applications, whether it is a smartphone or a rechargeable lithium-ion battery, or a lead-acid battery, understanding these terms can allow you to make informed decisions when facing some problems, ensure battery performance and improve safety.
If you want to understand your energy needs and find the right battery for your application, please contact our battery experts or send an inquiry directly below.