Safety tests for lithium batteries mainly include the following aspects: They must pass safety tests such as overcharge, short circuit, acupuncture, extrusion and impact of heavy objects . The battery must only not catch fire or explode. are the specific methods. :
1. Overcharge Test
Fully charge the lithium battery and perform an overcharge test according to 3C overcharge. When the battery is overcharged, the voltage rises to a level. certain tension and stabilizes for a certain time. , the battery voltage increases rapidly as a certain time approaches. When it reaches a certain limit, the battery cap is removed and the voltage drops to 0V. It does not catch fire or explode.
2. Short circuit test
Once the battery is fully charged, short circuit the positive and negative poles of the battery with a wire whose resistance does not exceede step 50 mΩ, and test the battery surface temperature change. The maximum surface temperature of the battery is 140℃, the battery cap is opened, and the battery will not catch fire or explode. Acupuncture test: Place the fully charged battery on a flat surface and use a 3mm diameter steel needle to pierce the battery in the radial direction. Test the battery only if it does not catch fire or explode; Compression test: Place the fully charged battery on a flat surface, apply a compression force of 13+1KN from the hydraulic cylinder, and press the battery flat with a steel rod with a diameter of 32mm, once pressure extrusion level reached, stop extruding and the battery will not catch fire or explode.
3. Impact test on a heavy object
Once the battery is fully charged, place it on a flat surface, place a steel column ofn diameter of 15.8 mm vertically in the center of the battery and place a 9.1 kg. The heavy object falls freely from a height of 610 mm onto the steel column above the battery, as long as the battery does not catch fire or explode.
What are the testing standards for lithium batteries?
If you doubt whether the capacity of the lithium battery matches the rated value, you can make a preliminary judgment by following the steps:
1. Use a suitable charger to fully charge the battery.
2. Use a load (such as a light bulb or resistor) connected to the positive and negative terminals of the battery to drain power from the battery.
3. Record charging usage time and monitor battery voltage changes.
4. According to the relationship between charging current and time, calculate the total battery charge quantity of the full chargeete to the empty charge, that is to say the capacity.
For example, assuming the charging current is 1A and the battery works for 20 hours under load, the capacity calculation formula is: Capacity (Ah) = Current (A) × Time (hours) = 1 A × 20 h. = 20Ah.
With this method, you can first determine whether the battery capacity is close to the nominal value. If the measurement results differ significantly from the rated capacity, there may be a capacity problem. At this point, it is recommended to contact the battery manufacturer or supplier for solutions or more accurate testing.
It should be noted that this method can only provide an approximate capacity value and may be affected by factors such as testing environment, charging characteristics and battery condition . In order to obtain more accurate capacitance measurement results, you canUse professional testing equipment or consult professionals.
How to detect lithium batteryIf the battery capacity is qualified
1. Voltage measurement method
That is, the battery capacity is obtained by simply monitoring the battery voltage. Advantages of this method: simplicity Disadvantages: imprecise, the precision of the power measurement is only greater than 20%. Especially when the battery charge is less than 50%, the phone power calculation will become very inaccurate. Battery protection by this method is therefore very limited.
2. Battery modeling method
This method involves creating a data table based on the battery discharge curve. The data table will show the power values at different voltages. Advantages: More accurate than the voltage test method. Disadvantages: Obtain a technical sheetPrecise icing is not simple because the relationship between voltage and power also involves factors such as battery temperature, self-discharge and aging.
Early developments of lithium batteries
Lithium batteries were first used in pacemakers. Lithium batteries have the advantages of extremely low self-discharge rate and gentle discharge voltage, allowing pacemakers implanted in the human body to work for a long time without recharging. Lithium batteries typically have a voltage rating above 3.0 volts and are best suited for use as an integrated circuit power supply. Manganese dioxide batteries are widely used in calculators, digital cameras and watches.
In order to develop more efficient varieties, various materials were researched to create unprecedented products.
In 1992, Sony successfully developed lithium-ion batteries. Its practicality has significantly reduced the weight and volume of portable electronic devices such as cell phones, laptops and calculators.
Lithium battery capacity refers to the amount of electricity it can hold. The unit is usually "ampere-hour" or "milliampere-hour". For example: the capacity of a lithium battery is 500 mAh, which means that if the battery current is 10 mA in operation, it can work continuously for 50 hours.
Lithium battery capacity test is based on full charge voltage and termination voltage set as parameters. Since the minimum discharge voltage of the lithium battery is 2.75 V, therefore a voltage lower than 3 V makes no sense. Lithium battery testing; Current discharge fixe is generally expressed in C, and lithium batteries are generally tested with a discharge of 0.5 C.
1. Fully charge the battery. The voltage of a single lithium battery after full charging is 4.2V;
2. Use a multimeter to find a constant current of 0.5C; lithium battery. Compared to the battery In terms of capacity discharge, the final voltage is set to 3V;
3. Multiply the constant current discharge time by the discharge current to obtain the battery capacity; constant current discharge cannot reach two hours, then the standard It is not enough to say the voltage, and the lithium battery may be counterfeited.
After the lithium battery capacity test is completed, performance tests, electrochemical tests and other items should be carried out. During the testing process of 3C lithium batteries, battery test modules et high current shrapnel microneedle modules can be carried out. be used as connections. The conductive bridge can transmit large currents of 1-50A, and its performance is stable and reliable, which is conducive to stable testing.