Role Of The Lithium-ion Battery Protection Board

The lithium-ion battery protection board, often referred to as a Battery Management System (BMS) or Protection Circuit Module (PCM), plays a crucial role in managing and protecting lithium-ion batteries. Here are its main functions:

Overcharge protection 

The BMS monitors the voltage of each individual cell within the battery pack. If any cell reaches its maximum safe voltage level, the BMS will disconnect the charging source to prevent overcharging, which can lead to overheating, swelling, or even fire.

Over-Discharge Protection 

Similarly, the BMS monitors cell voltages during discharge. If any cell drops below a safe voltage level, the BMS will disconnect the load to prevent over-discharging, which can damage the battery or render it unusable.

Short-Circuit Protection 

In the event of a short circuit within the battery pack or an external short circuit, the BMS will cut off the flow of current to prevent excessive current flow, which can cause a thermal runaway and lead to safety hazards.

Temperature Management 

The BMS monitors the temperature of the battery cells and can trigger protective measures if the temperature exceeds safe limits. This can include shutting down the battery pack temporarily or limiting the charging/discharging current.

Balancing Cells 

In multi-cell lithium-ion battery packs, individual cells can have slight variations in capacity or voltage. The BMS can balance the cells by redistributing charge among them during charging to ensure that each cell reaches the same state of charge and voltage, thus extending the overall battery life.

3.2V 20A Low Temp LiFePO4 Battery Cell -40℃ 3C discharge capacity≥70% Charging temperature：-20~45℃ Discharging temperature: -40~+55℃ pass acupuncture test -40℃ maximum discharge rate：3C

READ MORE

Capacity Monitoring 

The BMS keeps track of the battery's overall state of health, capacity, and cycle count. This information is useful for determining the remaining battery life and identifying when the battery may need replacement.

Communication and Data Logging

Some advanced BMSs provide communication interfaces (e.g., SMBus, I2C) to connect with external systems, such as battery chargers or battery monitoring systems. They can also log data related to battery performance and safety events.

Alarm and Protection Alerts 

When the BMS detects a fault or abnormal condition, it can trigger alarms or alerts, such as LEDs or audible warnings, to inform the user or operator of the issue.

Safety Compliance 

BMSs are essential for ensuring that lithium-ion battery packs meet safety and regulatory standards, such as those set by organizations like the Underwriters Laboratories (UL).

Overall, the lithium-ion battery protection board is crucial for maximizing the safety, performance, and lifespan of lithium-ion battery packs by managing their voltage, current, and temperature, as well as ensuring balanced cell operation. It's a critical component in various applications, from consumer electronics to electric vehicles and renewable energy storage systems.

Overcharge Protection Voltage

The overcharge protection voltage, often referred to as the overcharge threshold or limit, is the maximum voltage level at which a lithium-ion battery is considered fully charged and should not be charged any further to prevent overcharging. It is a critical parameter set by the battery manufacturer and programmed into the Battery Management System (BMS) or Protection Circuit Module (PCM) to safeguard the battery against overcharging.

Low Temperature High Energy Density Rugged Laptop Polymer Battery Battery specification: 11.1V 7800mAh -40℃ 0.2C discharge capacity ≥80% Dustproof, resistance to dropping, anti - corrosion, anti - electromagnetic interference

READ MORE

The specific overcharge protection voltage can vary depending on the type and chemistry of the lithium-ion battery, as well as the design and specifications of the BMS or PCM used in the battery pack. However, in general, the overcharge protection voltage for most lithium-ion batteries falls within the range of 4.2 to 4.3 volts per cell.

For example, if you have a single-cell lithium-ion battery, the overcharge protection voltage might typically be set at 4.2 volts. This means that when the voltage of that cell reaches or exceeds 4.2 volts during charging, the BMS or PCM will take action to disconnect the charging source to prevent further charging and overcharging of the cell. 

It's important to note that exceeding the overcharge protection voltage can lead to safety hazards, including overheating, swelling, and even the risk of fire or explosion. Therefore, it's crucial to use chargers and charging systems that are designed to respect these voltage limits and to use lithium-ion  batteries only as intended by the manufacturer's specifications to ensure safe and proper operation.

Overcurrent Protection Voltage

Overcurrent protection voltage, often referred to as the overcurrent threshold or limit, is the voltage level at which a lithium-ion battery protection circuit, such as a Battery Management System (BMS) or Protection Circuit Module (PCM), activates to limit or interrupt the flow of current in the battery pack in order to prevent excessive current draw or discharge, which can be harmful to the battery. 

The specific overcurrent protection voltage can vary depending on the design and specifications of the battery protection circuit and the application. It is typically set to a level where the current being drawn from the battery exceeds the safe operating limits. When the voltage across a current-sensing element (such as a shunt resistor) in the protection circuit reaches or exceeds the overcurrent protection voltage, the protection circuit takes action to limit the current or disconnect the load.

The overcurrent protection voltage is designed to protect the battery and the device or system using it from the following situations:

Short Circuits 

In the event of a short circuit within the battery pack or in the external circuitry, the current can increase dramatically. Overcurrent protection will kick in to prevent excessive current flow that could lead to safety hazards, overheating, or damage.

Excessive Load

If the connected device or system draws more current than the battery can safely provide, the overcurrent protection can limit the current to protect the battery from potential damage.

Abnormal Conditions 

Overcurrent protection can also activate in situations where the battery experiences an abnormal condition that causes a sudden surge in current, such as a malfunction or a fault in the device.

The specific voltage level for overcurrent protection varies depending on the battery's capacity, chemistry, and the design of the protection circuit. In many cases, it's a carefully selected threshold based on the battery's specifications and safety requirements.

It's important to note that overcurrent protection is a crucial safety feature, as excessive current can lead to thermal runaway, which can result in battery failure, fires, or other hazardous situations. Properly designed and calibrated overcurrent protection is essential for the safe operation of lithium-ion batteries in various applications.

Over discharge recovery voltage 

Over discharge recovery voltage is a critical parameter in the management of lithium-ion batteries and is typically associated with the Battery Management System (BMS) or Protection Circuit Module (PCM) in a battery pack. This voltage level represents the point at which the BMS allows the battery to resume normal operation after it has been temporarily disconnected or put into a low-power state due to over discharge.

Here's how over discharge recovery voltage works.

Monitoring Voltage 

The BMS continuously monitors the voltage of each individual cell within the battery pack during discharge. When the voltage of any cell drops to or below a certain threshold, it is considered over discharged. Over discharge can lead to damage and a reduction in the battery's lifespan.

Over Discharge Protection 

To prevent over discharge, the BMS will take action when it detects that the voltage of one or more cells has dropped below the over discharge protection threshold. This action typically involves disconnecting the load (the device or system using the battery) to prevent further discharge.

Recovery Voltage

The over discharge recovery voltage is the voltage level at which the BMS allows the battery to resume normal operation after the over discharge condition has been corrected. When the voltage of the cells rises above this recovery threshold, the BMS will reconnect the load, and the battery can supply power again.

The specific over discharge recovery voltage varies depending on the battery's chemistry and the design of the BMS. For lithium-ion batteries, the over discharge recovery voltage is often set around 2.5 to 3.0 volts per cell. Once the voltage of the individual cells or the battery pack rises above this threshold, the BMS will consider the over discharge condition resolved and allow the battery to be used safely again.

Over discharge protection and recovery are crucial for preventing deep discharge, which can be detrimental to lithium-ion batteries. Deep discharging can lead to capacity loss, reduced battery lifespan, and even permanent damage. Properly setting and implementing over discharge recovery voltage thresholds helps extend the life of lithium-ion batteries and ensures their safe operation.