How do lead-acid battery chargers prevent battery overheating?
Publish Time: 2025-09-04
With the increasing popularity of vehicles like electric bicycles and electric tricycles, lead-acid batteries, as a primary power source, have drawn significant attention to their safety and lifespan. Charging is particularly critical during battery use. Improper charging methods can easily lead to battery overheating, which can cause swelling, shortened lifespan, and even accidents. Therefore, modern intelligent lead-acid battery chargers incorporate multiple technical measures in their design, from circuit control and material selection to structural optimization, to comprehensively prevent battery overheating and ensure a safe and efficient charging process.
1. Intelligent Startup Protection: Preventing Overheating Caused by Deep Battery Depletion
When a lead-acid battery has been unused for an extended period or has been over-discharged, its voltage may drop below normal. Immediately charging with a high current in this state can cause a violent reaction within the battery, generating significant heat and rapidly heating the battery. To mitigate this risk, intelligent chargers feature a "low-voltage pre-charge" function. When the battery voltage is detected to be below 10.5V, the charger automatically initiates a low-current trickle charge to slowly restore the battery voltage. If the battery voltage fails to rise above 10.5V within 30 minutes, the battery may be severely damaged or short-circuited. The charger will automatically stop charging to prevent heat accumulation caused by continuous low current input, effectively avoiding the risk of overheating due to deep battery depletion.
2. Thermal Runaway Control Program Introduced During the Constant Current and Constant Voltage Phases
After the battery voltage returns to the normal range, the charger enters the constant current charging phase and then switches to constant voltage charging. These two phases are when energy input is most concentrated during the charging process and are also the most prone to overheating. To this end, advanced chargers have a built-in "Thermal Runaway Control Program." This program dynamically adjusts charging parameters by monitoring battery voltage, current, and temperature trends in real time. If the system detects a rapid voltage increase and a slow current decrease, or an abnormally high case temperature, indicating a potential risk of thermal runaway, the charger will automatically reduce the output current or suspend charging until the temperature drops, resuming charging again. This effectively prevents battery swelling or damage caused by high temperatures.
3. Pulse Repair Technology Delays Plate Sulfation and Reduces Internal Resistance and Heat Generation
Over long-term use, lead-acid batteries are prone to the formation of lead sulfate crystals (also known as sulfation) on the plate surface, increasing internal resistance. Increased internal resistance converts more electrical energy into heat during charging, exacerbating battery heating. To address this issue, some high-end chargers incorporate a "pulse repair" function at the end of constant-voltage charging and before entering the float charge phase. This function intermittently applies high-voltage pulses to break up lead sulfate crystals on the plate, restoring the reactive capacity of the active materials. This not only extends battery life but also significantly reduces heat generation caused by excessive internal resistance, mitigating overheating risks at the source.
4. High-Quality Materials and Structural Design Ensure Heat Dissipation and Safety
In addition to circuit control, the material selection and structural design of the charger itself are also crucial to preventing overheating. First, the charger's PCB and casing are both made of flame-retardant materials (such as PC or ABS with flame retardants), effectively preventing the spread of flames even in the event of a short circuit. Secondly, the internal potting compound is made of polyurethane (PU) with a thermal conductivity greater than 0.7 W/cm2. This not only provides moisture and shock resistance but also quickly conducts heat generated by the PCB to the outer casing, improving overall heat dissipation efficiency.
5. Modular Design Enhances Compatibility and Maintenance Ease
The charger's output port adopts a plug-in design, allowing users to replace the corresponding charging head according to different electric vehicle brands, avoiding poor contact, increased resistance, and heat generation caused by interface mismatches. This modular design not only enhances product versatility but also facilitates future maintenance and replacement, further ensuring the stability and safety of the charging system.
The lead-acid battery charger utilizes intelligent control algorithms, thermal management technology, high-quality materials, and user-friendly design to create a multi-level overheating protection system, comprehensively ensuring charging safety and extending battery life.
