Needle prick battery test has been an important indicator of the safety performance of lithium batteries for a long time, but Ningde Time insiders said that passing the needle prick is not equal to battery safety, and not doing the needle prick test is not equal to battery insecurity.
The insider said that many people will now confuse the safety test of power batteries with the abuse test, and the needle prick test belongs to the old abuse test. The safety test is a corresponding test developed in conjunction with certain scenarios and with the goal of personnel protection. Abuse testing refers to the exploration of some battery performance boundaries under very extreme circumstances.
Not long ago, BYD showed a new weapon - the blade battery. Once this battery was released, it attracted a lot of attention. The competitive situation between BYD and Ningde Times has also become more tense.
Previously, BYD has repeatedly proved its safety through "pinprick test", and the opposite case on a pinprick on the fire of ternary lithium batteries. China's top power battery Ningde Time's main product is ternary lithium batteries, so the test was interpreted by some people as BYD in the Ningde Time "show muscle".
In addition to better space utilization, the biggest publicity point of the blade battery is safety. However, Ningde Times believes that BYD is "confusing the concept".
In response to the pinprick test, the media spoke with a Ningde Times insider. The person said to the media, through the needle is not equal to the battery safety, do not do the needle test is not equal to the battery is not safe: "The safety of the power battery is mainly in the system thermal safety, mechanical safety, electrical safety and functional safety, and not only the safety of the electric core." In its view, needling a single cell is similar to ignition testing the flammability of gasoline and diesel, completely ignoring the protective role of the fuel tank.
BYD Sales Co., Ltd. assistant general manager Du Guozhong also admitted that the pinprick is for extreme conditions scenario testing, generally does not occur, and now all battery packs have high-strength shell protection, consumers do not have to worry too much. But he also stressed that different types of batteries have different performance in the pinprick experiment, or and battery materials, enterprise technology, technology and quality control level is closely related, is of some significance.
To this day, in the field of batteries up to more than 300 test methods, it is recognized that the most difficult is still the needling test.
As the new energy vehicle industry started substantially later than 3C electronic products, so the test standards related to automotive power batteries in the early stage directly referenced the 3C consumer electronics battery test.
Needle test originated from the early 21st century 3C consumer electronics lithium-ion battery abuse safety test requirements, used to simulate the consequences of thermal runaway caused by external sharp foreign body piercing the bare battery cell. At that time, in order to pass the pinprick test, many electronic products have built-in design protection in terms of short-circuit discharge, a design that takes up space and often leads to improper start-up.
What is the difference between safety testing and abuse testing of power batteries?
Today's power battery packs almost all use 20mm thick aluminum profiles to make the shell, strong and durable, and corrosion-resistant, ordinary small steel nails and other external sharp objects can not pierce this shell, there is no chance to pierce the internal modules and cells.
In 2012, 3C consumer electronics lithium-ion battery abuse safety testing requirements standard revision process, the needle test requirements were removed.
On May 18, the first mandatory national standard in the field of electric vehicle power batteries in China, "Safety Requirements for Power Batteries for Electric Vehicles", explicitly eliminated the pinprick test, and the pinprick test is no longer evaluated separately in this standard.
"In reality, the situation of the battery cell being pinpricked will not happen, the bottom of the battery pack 'blunt stab' and extrusion is the test method that is more in line with the real scenario," Ningde Time insiders said, "At present, the car companies and battery companies All have included the bottom ball strike test in the experimental requirements."
The three reasons given for the cancellation of the pinprick test are: the IEC (International Electrotechnical Commission) battery standard does not use pinprick; according to past experience pinprick does not match the actual failure mode; "new energy vehicle manufacturers and product access management regulations" stipulates that pinprick is a temporary non-implementation item.
Ningde Times insiders said that lithium iron phosphate batteries are easier to pass the needling is not because of advanced technology, but because the material itself is thermally stable, but for the higher energy density of ternary batteries, needling is a challenge, but not impossible to pass.
The new national standard in the adjustment of the battery monomer, module test, while focusing on strengthening the battery system thermal safety, mechanical safety, electrical safety and functional safety requirements. In particular, the standard adds a battery system thermal dispersion test, which clearly requires the battery system not to catch fire or explode within 5 minutes after the thermal runaway of a single battery unit, leaving a safe escape time for the occupants.
Welcome to visit our company website: www.manlybattery.com. If you have any interests in batteries, please feel free to contact us: info@manlybattery.com
