In recent years, with the power battery set off a boom, the safety of power battery has been concerned. Many people wonder know more about the safety of power batteries. In addition to needling tests, what other tests have power batteries been subjected to? What are the important effects of different tests? Let’s find out.
As a matter of fact, whether it is lithium battery or battery, due to the particularity of its application field makes people’s requirements for the safety performance, reliability and cycle life of the battery more and more high, power battery production process is long, in addition to more than 50 production processes, It also includes battery charge/discharge performance test, battery cycle life test, battery capacity test, quality assurance delivery/incoming testing, production testing and other testing procedures. On the basis of improving manufacturing technology, we must also pay attention to battery product performance test.
Important power battery test items:
1、Crush test: to ensure the safety of life in collision accidents
First of all, extrusion test is an indispensable and important project of power battery test. It can simulate the collision of the car and test the safety performance of the power battery under the condition of extrusion deformation of the power battery. Of course, different countries have different standards for power batteries, and China’s national standards are strict for extrusion test: power batteries can be deformed up to 30%, and no fire or explosion can occur within one hour.
Power battery in the automotive field must also ensure a certain degree of safety, in some traffic accidents do not explode, do not fire, can ensure that the owner from secondary injury, but also in the maximum protection of the owner’s life and property safety, this is today BYD and other emerging new energy vehicles for power battery safety requirements.
2、Overcharge test: designed to prevent charging system failure
Due to the failure of the charging system, the battery continues to charge under the condition of full charge, resulting in overcharge, which leads to the spontaneous combustion of the power battery has happened many times.
The stronger the anti-overcharge ability of the power battery, the lower the chance of spontaneous combustion accidents. The overcharge test can simulate the condition of overcharge to detect the thermal runaway ability of the battery. The overcharge test needs to be applied to the thermal diffusion testing machine. The thermal diffusion testing machine can not only choose the overcharge mode, but also choose the heating mode for testing! Of course, in different countries, the standard of power battery is not the same, and China’s national standard requires the termination of charging with 1 rate current constant current to 1.5 times of the termination voltage, and observation for one hour shall not appear fire, explosion phenomenon. It is necessary to reduce the probability of spontaneous combustion caused by overcharge with a higher anti-overcharge standard, so as to improve the safety performance of various devices, machines, vehicles and ships that apply power batteries.
3、Forced cell thermal control: the whole package is still sitting
Thermal runaway is the trigger for power battery of spontaneous combustion and thermal runaway is often because lithium-ion batteries in the extrusion deformation, puncture or high temperature burning led to the destruction caused the diaphragm is negative short circuit, or due to external short circuit batteries, lithium ion battery within a short period of time accumulated a lot of heat, cause is the cathode active material and electrolyte decomposition, Lithium-ion battery fire and explosion, a serious threat to the user’s life and property safety. Take the forced thermal runaway test of BYD’s blade battery as an example. The thermal runaway of a single battery in the battery pack was artificially caused, and the safety performance of the whole battery pack was observed.
With the self-insulation and flame retardant system of the blade battery, there is no thermal runaway of the adjacent cell. The maximum temperature of the nearby cell is 80°C, which does not reach the temperature condition of thermal runaway of the lithium iron phosphate battery. Thermal runaway in a single cell does not trigger a chain reaction in neighboring cells, so the safety of the whole pack remains the same.
4、Furnace temperature test: bake power battery high temperature safety barrier
Furnace temperature test, also known as heating test, is mainly used to test the safety performance of power battery under high temperature conditions. Of course, in different countries, the power battery standards are different, and China’s national standard requires that the power battery be heated to 130°C by continuous heating, and maintain the temperature for 30 minutes, during this period, the power battery can not fire, explosion phenomenon. And the blade battery using lithium iron phosphate material, high temperature performance is more excellent. In case of fire and other conditions, the super high temperature resistance of the blade battery can also be enough to ensure the safety of the battery to the maximum extent in the high temperature environment.
5、Drop test: to investigate the ability of the power battery to resist accidental impact
Most of the batteries on the market need to pass the UN38.3 test project. UN38.3 requires that lithium batteries must pass the height simulation, high and low temperature cycle, vibration test, impact test, 55℃ external short circuit, impact test, overcharge test and forced discharge test before transportation, in order to ensure the safety of lithium battery transportation. If the lithium batteries are not installed with the equipment and each package contains more than 24 cells or 12 cells, a 1.2-meter free drop test is also required. UN38.3 is designed to make batteries better transported by sea, land and air to various countries and regions.
During air transportation, batteries are prone to short circuit in the environment of sometimes high temperature and sometimes low temperature. The turbulence in the air will make the batteries collide with each other, and the vibration caused by take-off and landing will also have a certain impact on the batteries. The battery contains chemicals and environmental uncertainties, which also require the battery to undergo UN38.3 tests before being airlifted. Batteries are packaged differently because of the way they are shipped by air. Under normal circumstances, there are three types of battery shipment: separate shipment of batteries, shipment of batteries with the product package, and shipment of batteries installed in the product. However, the 1.2m drop test report is only required in the third case, and the other two methods should be provided. Especially when the batteries are shipped separately in the card slot, the batteries are dangerous goods, so the requirements are more stringent.
The battery drop test needs to be applied to the corresponding battery drop testing machine, which is dedicated to testing the damage of product packaging when it falls, and evaluating the impact resistance strength during transportation and handling process. Adopt double column guide, height drop times can be set, the work is stable and reliable, can realize the edge, plane, Angle drop, meet GB/ T48575-92, ISO2248-1972E. Battery drop testing machine generally adopts photoelectric control, can freely choose the drop height, drop release using electromagnetic control, can make the sample instantly free fall, the edge of the packaging container, Angle, plane drop impact test.
In fact, this article only covers five of the most important power battery tests. We will update this knowledge on the rest of the battery tests, you will also stay tuned to our blog if you’re interested.Last but not least, there is a wide variety of devices in the market for testing the safety of power batteries, which should be carefully selected according to the actual test requirements and conditions. For example, the selection of extrusion testing needs to be applied to the extrusion needle testing machine, vertical cell extrusion testing machine, horizontal battery extrusion testing machine, extrusion needle all-in-one machine, horizontal battery pack extrusion needle testing machine and other testing machines. But how do these machines pick and choose? Don’t worry, Guangdong Bell Experiment Equipment Co., Ltd. has all the special safety testing equipment for batteries and special environmental testing equipment for new energy. In addition, we also provide one-stop quality service for you. We are looking forward to your visit.