There is lithium worry: how to choose the right lithium battery products

With "ultimate energy" and "green energy," said the lithium-ion battery, since the 1990s came from button batteries electronic products, mobile phones, DC digital products lithium batteries to electric vehicles in power storage battery, is increasingly widely used in people's production and life. Compared with other batteries , lithium-ion batteries have great advantages in terms of volume, weight and performance.

Use a lithium battery within a reasonable voltage capacity range

One-sided pursuit of ultra-large capacity, ultra-high voltage is wrong. First of all, everything must go through a process from simple to complex and difficult to easy. It is like flammable gas. It is relatively easy to ensure the safety of the lighter. It is much harder to ensure the safety of the fuel tank. The situation of the car's fire and explosion at the time of the crash has not yet been fully solved. The more energy that accumulates in a limited volume, the less manageable it is. Currently, Suzhou Xingheng can only guarantee the safety of a battery combination of up to 48V10Ah. Secondly, the higher the voltage, the larger the capacity, the greater the difficulty and failure rate of the protection circuit and the equalization circuit. Therefore, Suzhou Xingheng does not advocate or support the battery combination exceeding 48V10Ah.

Safety testing and certification depends on lithium batteries

First, UL certification

Today, most countries and regions in the world require safety certification for products that involve safety, sanitation, and environmental protection. The UL Mark has become one of the world's leading safety certification marks.

The test criteria are as follows:

1, the shell

Lithium battery case should have sufficient strength and rigidity sufficient to resist the pressure of the indiscriminate, without causing fire. User-replaceable lithium battery should have sufficient strength they would not hurt people.

2, electrolyte

User-replaceable batteries should not contain pressurized vapor or toxic vapors and liquids that can cause eye damage, or the battery case should be less than 5 ml under normal laboratory conditions (temperature 23 ° C).

3, use

Lithium batteries should take measures to avoid the use of an abnormal charging current, the battery has an acceptable test charging current Ic,, protective measures should be used in the end product under abnormal conditions.

4, leakage

Leakage or leakage quality loss standard, the maximum loss of mass of battery or battery does not exceed 1g0.5%, 1~5g0.2%>5g0.1%.

5, mechanical test

(1) Extrusion: A pressure of 13KN (pressure 17.2 MPa) is applied to two flat surfaces of the battery through a hydraulic piston having a diameter of 32 mm, and the pressure is released when the maximum pressure is reached. The sample does not ignite or explode.

(2) Impact: A rod having a diameter of 15.8 mm was placed in the center of the sample, and a weight of 9.1 kg was dropped from the height of 610 mm onto the sample. The sample does not ignite or explode.

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

(4) Vibration: The battery is subjected to simple tuning vibration (in three mutually perpendicular directions), the vibration frequency is varied at a rate of 1 Hz/min in the range of 10-55 Hz, and recovered back within 90-100 min with an amplitude of 0.8 mm. The sample should not ignite, explode, or leak.

(5) Thermal shock: The sample was heated in a natural convection or forced convection oven, and the oven temperature was raised to 150 ° C at a rate of 5 ± 2 ° C / min, and stopped after 10 min. The sample should not ignite or explode.

(6) Thermal cycle test: The battery is placed in the test chamber and subjected to the following cycles:

?? Warmed to 70 ± 3 ° C within 130min, and kept for 4h.
?? Cool down to 20 ± 3 ° C within 230 min, keep warm for 2 h.
?? Warmed to 40 ± 3 ° C in 330min, and kept for 4h.
?? Cool down to 20 ± 3 °C within 430min.
?? 5 repeat the above cycle 9 times.
After 610 cycles, the battery was left for 7 days for inspection. The sample should not ignite, explode, or leak.

(7) High-altitude simulation: The sample battery was stored for 6 hours at an absolute pressure of 11.6 Kpa (1.68 psi) and 20 ± 3 ° C (68 ± 5 ° F). The sample battery does not explode or ignite, and there must be no perforations or leaks.

6, charge and discharge test

(1) Charge and discharge cycle: The test temperature was 25 ° C, and the cell was subjected to a charge and discharge cycle according to the manufacturer's requirements, and was cycled until the capacity was 25% of the initial nominal capacity or 90 days after the continuous cycle. The sample should be free of any safety events.

(2) Short-circuit test: short-circuit the positive and negative terminals of the battery with a copper wire with a resistance value less than 0.1 Ω, discharge the battery until it catches fire or explode, or until the battery is completely discharged, the temperature of the casing is again lowered to room temperature (test at room temperature 60 Performed at ±2 °C). The sample shall not ignite or explode, and the temperature of the outer casing or battery case shall not exceed 150 °C.

(3) Abnormal charging test: After the normal discharge is completed, the current is charged at a current three times the normal charging current. No fire, no explosion.

(4) Forced discharge test: The battery core is completely discharged at room temperature, and after a series of new batteries of the same type are connected in series, the formed battery pack is short-circuit tested. The sample should not ignite or explode.

(5) Overcharge: the battery at full power conditions to 3C, 10V constant current, constant voltage to charge the battery, when the current reaches 100mA, converted to constant voltage charge for 48 hours.

7, the logo

The battery should identify the manufacturer's name, brand name or trademark, and style settings. The battery should be labeled Warning and have a corresponding description.

Second, the Extra Energy standard

Extra

Energy certification is a non-profit organization based in Germany Tanzania to take, the main work is focused on the global information neutrality of light electric vehicles, and provide value-added services, safety testing related to lithium batteries is very strict, rigorous, get Recognized by most European customers.

The test criteria are as follows.

Test method pre-test state test method safety standard

1 Abnormal charging room temperature, air and electricity, factory assembled. Removal of the protective circuit and management circuit, in the case where the battery pack is fully charged, the battery pack 10A through the charge current to 1.5 times the nominal voltage.

No fire, no explosion; battery temperature of the test process is less than 120 ° C; the experimental wooden table is not burnt; the release of gas is non-toxic.

2 short circuit

At room temperature, the original charger is fully charged and assembled at the factory.

The protection circuit and the management circuit are removed, and when the battery pack is fully charged, the positive and negative terminals of the battery pack are directly short-circuited.

No fire, no explosion; battery temperature of the test process is less than 120 ° C; the experimental wooden table is not burnt; the release of gas is non-toxic.

3 Heavy objects are squeezed at room temperature, the original charger is fully charged, and the original factory is assembled. A 15 cm diameter steel roll with a pressure of 10 tons squeezes the battery pack.

No fire, no explosion; gas, solids and liquids spilled from the battery are non-toxic.

Third, CE certification

In recent years, in the markets of the European Economic Area (European Union, European Free Trade Association, except Switzerland), the use of CE certification marks has increased, and the products bearing the CE certification mark indicate that they are safe. Requirements for a series of European directives such as health, environmental protection and consumer protection.

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