How to select power lithium battery products correctly?

Lithium batteries within reasonable voltage capacity should be used.

It is wrong to pursue a one-sided approach to super-capacity and ultra-high voltage. In the first place, everything has to go through a process from simple to complex, from difficult to easy, just as it is also flammable gas. It is relatively easy to effectively guarantee the safety of lighters, and it is much more difficult to effectively ensure the safety of car fuel tanks. The circumstances of the car explosion at the time of the crash have not yet been fully resolved. The more energy accumulated in a limited volume, the more difficult it is to manage. At present, Suzhou Xingheng can only guarantee the safety of batteries with a maximum of 48V10Ah. Second, the higher the voltage, the larger the capacity, the greater the difficulty and failure rate of the protection circuit and the equilibrium circuit. Therefore, Suzhou Xingheng does not advocate and does not support battery combinations that exceed 48V10Ah.

To see the safety test certification of the lithium battery

UL Certification

Today, most countries and regions in the world require safety certification before entering the market for products involving safety, health, and environmental protection. The UL logo has become one of the world's most famous safety certification symbols. The test criteria are as follows:

1, shell

The lithium battery case should be strong enough and rigid enough to withstand the overstretched pressure without causing fire. Substitutable lithium batteries should be strong enough not to hurt people.

2, electrolytes

Subscriber replaceable batteries should not contain pressure vapour or toxic vapor and liquids that spew out damaging eyes, or the battery case should be under normal laboratory conditions(temperature 23 °C), and the fluid leaked during impact should be less than 5ml.

3, use

Lithium batteries should be used to take measures to avoid abnormal charging currents. The tested battery has an acceptable charging current Ic. Under abnormal conditions, protective measures should be used in the terminal product.

4, leakage

Leakage or leakage quality loss standard, the maximum mass loss of the core or battery does not exceed 1g0.5 %, 1 ~ 5g0.2 % & GT; 5G 0.1 %.

5, mechanical test

(1) Extrusion: Pressure 13KN(pressure 17.2 Mpa) is applied to the two flat surfaces of the battery by means of a 32 mm diameter hydraulic piston, which releases pressure when the maximum pressure is reached. Samples do not catch fire or explode.

(2) Impact: a 15.8 mm diameter rod is placed in the center of the sample so that a weight weighing 9.1 Kg falls from a height of 610mm on the sample. Samples do not catch fire or explode.

(3) Acceleration: The battery is placed on a fixed fixture and accelerates in three perpendicular directions(acceleration requirements: the minimum average acceleration within the initial 3ms should be 75g, and the peak acceleration should be between 125-175g). Test temperature 20 ± 5 °C. The sample shall not catch fire or explode, and the sample shall not leak.

(4) Vibration: The battery is subjected to simple tuning vibrations(in three mutually perpendicular directions), and the vibration frequency changes at a rate of 1 Hz / min in the 10-55 Hz range and recovers within 90-100 min with an amplitude of 0.8 mm. Samples shall be free from fire, explosion and leakage.

(5) Thermal shock: The sample is heated in a natural convection or forced convection oven, and the oven temperature heats up to 150 °C at a speed of 5 ± 2 °C / min and stops at 10 min. Samples shall not catch fire or explode.

(6) Thermal cycle testing: Batteries are placed in the test room and subjected to the following cycles:

1 Heating up to 70 ± 3 °C within 30 min, heat preservation 4h.

2 30 min cooling to 20 ± 3 °C, insulation 2H.

3 30 min heat up to 40 ± 3 °C, thermal insulation 4h.

4 30 min cooling to 20 ± 3 °C.

5 Repeat the above loop 9 times.

After 10 cycles, the battery is placed for 7 days for inspection. Samples shall be free from fire, explosion and leakage.

(7) High-altitude simulation: The sample battery is stored at an absolute pressure of 11.6 Kpa(1.68 psi) and 20 ± 3 °C(68 ± 5 °F) for 6 hours. The sample battery does not explode or catch fire and can not be perforated or leaked.

6, charging and discharging test

(1) Charging cycle: Test temperature 25 °C, the core is charged and discharged according to the manufacturer's requirements, and the cycle ends when the capacity is 25 % of the initial nominal capacity or after 90 consecutive cycles. Samples should be free of any security incidents.

(2) Short circuit test: Short connection of the positive and negative poles of a battery with a copper wire with a resistance of less than 0.1 Ω, and discharge of the battery until it catches fire or explodes, or until the battery is fully discharged, The temperature of the shell dropped back to room temperature(the test was conducted at room temperature at 60 ± 2 °C). Samples shall not catch fire or explode, and the temperature of the housing or battery housing shall not exceed 150 °C.

(3) Unnormal charging test: After normal discharge, charging at 3 times the normal charging current. No fire, no explosion.

(4) Compulsory discharge test: The core is fully discharged at room temperature and short-circuit the formed battery pack after being connected in series with a certain number of new cores of the same model. Samples shall not catch fire or explode.

(5) Overcharge: The battery charges the battery at 3C, 10V constant current and constant pressure under full power conditions. When the current reaches 100mA, it is converted to constant voltage for 48 hours.

7, marking

The battery shall identify the manufacturer's name, trademark or trademark, and the style setting. The battery should identify Warning and be described accordingly.

ExtraEnergy standard

ExtraEnergy Certification is a non-profit organization headquartered in Tanner, Germany. Its main task is to concentrate information on the neutrality of light electric vehicles around the world and provide value-added services. The safety detection of related lithium batteries is very strict and rigorous. Most European customers recognize. The test criteria are shown in the table below.

Test Method Pre-test State Test Method Safety Standard

1 Non-normal charge room temperature, air power, original assembly. Remove the protective circuit and the management circuit. When the battery pack is full of electricity, the battery pack is charged with 10A current to 1.5 times the nominal voltage. No fire, no explosion; The temperature of the cell shell is less than 120 °C during the test process; The experimental wooden table is not scorched; The gas released is non-toxic.

2 Short circuit room temperature, original charger filled to full power, original assembly. Remove the protective circuit and the management circuit. If the battery pack is full of electricity, the positive and negative poles of the battery pack will short-circuit directly. No fire, no explosion; The temperature of the cell shell is less than 120 °C during the test process; The experimental wooden table is not scorched; The gas released is non-toxic.

3 Heavy weights squeeze at room temperature, the original charger is filled to full power, and the original factory is assembled. A steel roller with a diameter of 15 cm and a pressure of 10 tons presses the battery pack. No fire, no explosion; The gas, solid and liquid spilled from the battery are non-toxic.

III. CE Certification

In recent years, the CE certification Mark has been increasingly used in the markets of the European Economic Area(the European Union, the European Free Trade Association countries, except Switzerland). The products marked with CE certification indicate that they meet the requirements expressed in a series of European directives such as safety, health, environmental protection and consumer protection.

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