Lithium batteries are widely used in mobile phones, laptops, electric tools, electric vehicles and other fields due to their high energy density, long service life and environmental protection characteristics. However, there are some potential safety hazards in the use of lithium batteries, such as overcharge, overdischarge, short circuit, abnormal temperature and other problems, which may lead to battery performance degradation or even safety accidents. Therefore, a key component of lithium Battery System is the protection board, also known as Battery Management System (Battery Management System, referred to as BMS). This article will deeply analyze why lithium batteries must be equipped with protection boards, and explain from the perspectives of safety assurance, battery performance maintenance and life extension.

I. Safety risks of lithium batteries and importance of protection boards

lithium battery has many potential risks due to its chemical properties and structural characteristics:

1. overcharge risk
   overcharging of lithium battery will cause the electrolyte inside the battery to decompose and generate gas, causing the battery to expand or even explode. Overcharging will also destroy the internal material structure of the battery and reduce the battery capacity and life.

2. Overdischarge risk
   when the battery voltage is too low, lithium ions cannot be normally embedded in the negative electrode material, resulting in the structural damage of the negative electrode material, the battery capacity permanently decreases, and even cannot be charged.

3. Risk of overcurrent and short circuit
   

4. Temperature anomaly risk
   lithium batteries are extremely sensitive to temperature. Too high or too low temperature will affect battery performance and safety. High temperature will accelerate battery aging and even cause thermal runaway, while low temperature will affect battery capacity and charge and discharge efficiency.

In order to effectively prevent the above risks, Protection Board (BMS) came into being. Through real-time monitoring and intelligent management, it realizes multiple protection of lithium batteries and ensures the safe and stable operation of the battery system.

II. Core functions of protection board (BMS)

the protection board is not only a simple safety switch, but also the "brain" of the lithium battery system. Its main functions include:

1. Overcharge protection

the protection board monitors the voltage of each battery cell to prevent the battery voltage from exceeding the safety threshold. Once the voltage exceeds the standard, BMS will cut off the charging circuit or limit the charging current to avoid damage and danger caused by overcharging.

similarly, BMS monitors the lowest voltage of the battery cell to prevent the battery voltage from falling to a dangerous level. Over-discharge can lead to battery capacity loss and performance degradation, and the over-discharge protection function of the protection board can effectively avoid such damage.

3. Over-current and short-circuit protection

the protection board can detect the charging and discharging current of the battery to prevent the current from exceeding the safety range. In case of short circuit or abnormal large current, the protection board quickly disconnects the circuit to prevent thermal runaway inside the battery.

4. Temperature protection

the Protection Board is matched with the temperature sensor to monitor the battery temperature in real time. When the temperature exceeds the safety range, BMS will take measures such as current limiting and power failure to avoid safety accidents caused by abnormal temperature.

5. Battery balance

lithium battery pack consists of multiple battery cells connected in series. The capacity and voltage of different cells may vary, resulting in the decline of the overall performance of the battery pack. The protection board adjusts the voltage difference of the single battery through the equalization function to prolong the battery life and ensure the consistent charging and discharging performance.

6. Data monitoring and communication

modern BMS has the capability of data collection and communication, which can transmit battery status information to the equipment control system, realize intelligent management and fault diagnosis, and improve battery use experience and maintenance efficiency.

III. Specific benefits of equipped protection board for lithium batteries

1. Improve security

through multiple protection measures, the protection board effectively prevents dangerous states such as overcharge, overdischarge, overcurrent, short circuit, abnormal temperature and so on, greatly reducing the risk of safety accidents such as battery explosion and fire, ensure the safety of users and devices.

2. Extend battery life

through balanced and precise management, the protection board can avoid excessive charging and discharging and unbalanced charging of single battery, slow down the attenuation speed of battery, increase the number of battery cycles and prolong the service life.

3. Improve battery performance stability

4. Convenient maintenance and management

the data collection and communication functions of BMS help users understand the battery status in real time, detect abnormalities in time, facilitate maintenance and management, and reduce failure rate.

IV. Lithium battery risk without Protection Board

lithium battery systems without protection boards lack necessary safety protection mechanisms and have serious hidden dangers:

• security risks increase significantly: abnormal states such as overcharge, overdischarge, and short circuit cannot be detected and handled in time, which can easily lead to safety accidents.
• Shortened battery life: There is no balanced management and the battery cell voltage is inconsistent, which leads to the decrease of battery pack performance and shortened service life.
• Unstable performance: The battery pack is prone to problems such as uneven capacity and voltage drift, which affects the normal use of the equipment.
• Maintenance difficulties: lack of monitoring and diagnosis methods, and it is difficult to prevent and deal with faults in a timely manner.

therefore, the lithium battery system must be equipped with a protection board to ensure safe and reliable operation.

Lithium battery as the core energy unit of modern electronic equipment and electric vehicles, although it has high energy density and good performance, its chemical characteristics and working conditions determine that there are many safety risks. As the safety guardian of lithium battery system, Protection Board (BMS) realizes overcharge, overdischarge, overcurrent, short circuit, through real-time monitoring and intelligent management of battery voltage, current and temperature, multiple protection functions such as abnormal temperature. This not only ensures the safe operation of the battery and equipment, but also effectively prolongs the battery life and improves the performance stability.