When the heat sweeps through the city, you start the electric car with full air conditioning, or charge the electronic products indoors, have you ever thought about what challenges these hidden batteries are experiencing?
Battery safety alarm bells are ringing, and an overcharge accident is enough to cause a huge risk.
Whether it is a ev or a mobile notebook, the core secret of protecting battery health is hidden in the chip of “Battery Management System (BMS)”. It silently assumes the responsibility of battery guardian, especially in extreme weather to maintain voltage balance, and becomes the ultimate line of defense between users and safety.
When we use every charging service safely, few people know that behind every battery unit, there is a set of precise algorithms in real-time operation.
How does it precisely control the charge and discharge boundary? How to avoid the battery attenuation caused by over-discharge? This article allows you to understand why the core technologies hidden in the depths of the battery pack can avoid a possible thermal runaway disaster at a critical moment.
When you use electronic devices in high temperature environment, this “hidden sense of security” comes from the silent guardianship of BMS.
Overcharge and overdischarge are common problems in the use of batteries, which not only shorten the battery life, but also may cause safety risks. One of the core functions of the Battery Management System (BMS) is to prevent the battery from overcharging and overdischarging, and to ensure that the battery operates within a safe range.
- Voltage monitoring and threshold setting
The BMS monitors the voltage of each battery cell in real time through a high-precision voltage sensor. These sensors can accurately measure the voltage change of the battery and transmit the data to the control unit of the BMS.
Under normal working conditions, the voltage of the battery will change with the charging and discharging process, but these changes are within a certain safe range.
In order to prevent overcharge and overdischarge, BMS will set the upper and lower voltage thresholds according to the characteristics of the battery. For example, for a common lithium-ion battery, the upper limit of the charging voltage is usually set at about 4.2 V, and the lower limit of the discharging voltage is set at about 2.5 V.
These thresholds are based on the chemistry of the battery and safety standards, ensuring that the battery will not be damaged or cause safety problems when operating in these voltage ranges.
2.Overcharge protection
When the battery is in the process of charging, the voltage gradually increases. The BMS continuously monitors the voltage of each battery cell, and once the voltage of a battery cell reaches a set upper threshold (for example, 4.2 V), the BMS takes immediate action:
1.Cut off the charging circuit: The BMS will cut off the charging current to the battery unit by controlling the charger or the vehicle’s charging system. This can prevent the battery voltage from continuing to rise, avoid the chemical reaction inside the battery caused by overcharge out of control, and thus prevent the battery from being damaged or causing fire.
- Alarm: At the same time, the BMS will send an alarm to the dashboard of the vehicle or the user’s device to remind the user that the battery is fully charged and needs to stop charging. This not only protects the battery, but also reminds users to pay attention to charging safety.
3.Over-discharge protection
During the discharge process, the voltage of the battery will gradually decrease. The BMS also continuously monitors the voltage of each battery cell, and once the voltage of a battery cell drops to a set lower threshold (for example, 2.5V), the BMS takes immediate action:
1.Cut off the discharge circuit: BMS will cut off the discharge current to the battery unit by controlling the power management system of the vehicle’s power system or equipment. This can prevent the battery voltage from continuing to drop, avoid the damage of the internal chemical structure of the battery caused by over-discharge, and thus prolong the service life of the battery.
- Alarm: At the same time, the BMS will send a low battery alarm to the user to remind the user to charge in time. In electric vehicle, this is usually achieved through a low battery indicator on the dashboard or an audible alarm to ensure that the driver can take timely action to prevent the vehicle from breaking down due to battery exhaustion.
- Dynamic adjustment and balanced management
In addition to a simple cutoff circuit, the BMS has more advanced features to prevent overcharge and overdischarge. For example, BMS can dynamically adjust the charging current and voltage to ensure that each battery cell can be charged evenly within a safe range.
For the battery cell with higher voltage, the BMS can properly reduce the charging current, and for the battery cell with lower voltage, the BMS can properly increase the charging current, so as to realize the equalizing charging of the battery pack.
During the discharge process, the BMS can also be dynamically adjusted in a similar way to ensure that the discharge current of each battery cell is uniform, so as to avoid the damage of individual battery cells due to excessive discharge.
This dynamic adjustment and equalization management not only improves the overall performance of the battery pack, but also prolongs the service life of the battery.
Every safe charging and stable endurance comes from the precise control of BMS technology. Behind the millivolt difference of battery voltage is the real-time monitoring of the sensor in milliseconds, the rigorous calculation of threshold setting, and the instantaneous response when the circuit is cut off.
When we enjoy the long endurance of electric vehicle and experience the convenience of continuous operation of electronic products, it is the balanced management of precise interception and dynamic adjustment of numerous overcharges and overdischarges that is supported.
With the development of solid-state battery and fast charging technology, BMS system will undertake a more complex regulatory mission-not only to meet the needs of users for fast charging, but also to ensure the intrinsic safety of batteries.
The upgrade path of energy storage batteries and EVs in the future is bound to be a process of co-evolution of battery chemistry system and intelligent management system.