Will it be easier for the new national standard to test for three Yuan batteries?

The industry broke the news that the revision and discussion of the mandatory new national standard for electric car lithium batteries have basically been completed and is about to enter the review stage. It is expected to be released in July 2019.

According to the Ministry of Industry and Information Technology, The new national standard is mainly based on GB/T31485 -2015 "Safety Requirements and Test Methods for Electric Vehicle power batteries" and GB/T31467.3 -2015 "Lithium-ion power battery Packages and Systems for Electric Vehicles" Part 3: Safety Requirements and Test Methods. The revised version of the two criteria(draft for comment) was combined and was finalized as an official version.

On the basis of the above two implementation standards, there are 18 new national standard adjustment parts, of which the elimination of single core acupuncture and the addition of lithium-ion battery packs or system thermal diffusion are the most controversial.

The following are the changes:

2 new: 1 Lithium-ion battery package or system thermal stability part 2: thermal diffusion; Overcurrent protection of lithium-ion battery system.

6 cancellations: 1 safety test of lithium-ion battery modules; 2 Lithium-ion battery monomer acupuncture; 3 Battery monomer drops, low pressure; 4 Lithium-ion battery monomer seawater immersion; 5 lithium-ion battery package or system drop; Lithium-ion battery pack or system flip.

10 modifications: Lithium-ion battery monomer overcharge; Monomer extrusion; Lithium battery package or system vibration; Vibration of an electronic device of a lithium battery package or system; Lithium battery pack or system mechanical impact; Lithium battery pack or system extrusion; Lithium battery package or system immersion safety; Lithium battery package or system thermal stability part 1: external fire; Battery pack or system salt fog; Battery system over temperature protection, external short circuit protection, overcharge protection, over discharge protection.

The testing equipment company believes that the revision of the above standards in the new national standard avoids repeated testing or redundant testing of products and simplifies the testing process. In particular, lithium ion battery packet or system flip, due to the slow speed of the flip test, high detection costs, simulation test is of little significance, cancellation is a wise choice.

It is worth noting that at present, the most controversial criteria for this new mandatory national standard that is about to land are the elimination of monolithic core acupuncture and the increase of lithium-ion battery packs or system thermal diffusion.

In general, the acupuncture test simulates the scene when the power cell encounters a sharp object. In the actual use of electric vehicles, there is a possibility that foreign matter penetrates the inside of the battery pack and causes the battery to short-circuit inside and outside.

The importance of acupuncture lies in the fact that when the test high-temperature steel is injected into the core, it will cause a short circuit in the battery, and the local temperature will rise sharply to exceed the reaction temperature of the active substance. The rapid reaction of the active substance will also release a lot of heat energy so that the chain reaction will continue. It could eventually trigger an explosion in the entire battery system.

In particular, the reaction of high nickel and NCA materials developed by power battery companies is more intense than that of other materials, which means that the difficulty coefficient of the single acupuncture test for high nickel ternary power core is increased.

The increased thermal diffusion test, according to the preparation of the draft for consultation, has four points worth noting: First, the overcharged contact heat out of control method is deleted, and acupuncture and heating are retained; The second is to indicate that the manufacturer(ie battery company or car company) can choose the trigger method for thermal runaway, but it must be stated in the test report; Third, it is necessary to provide a thermal diffusion occupant protection analysis report by the testing mechanism; Fourth, test reports should be provided by the testing organization, but no pass determination should be made.

Summarizing the opinions of all parties is mainly divided into pessimists and optimists. The pessimist believes that at present, only a small number of domestic battery companies of high nickel ternary batteries can pass the acupuncture test. The elimination of this test undoubtedly lowered the standard of clearance for other battery companies. There is even a pessimistic view that domestic battery companies will lose their future competitive advantage after the return of foreign battery companies.

The optimists believe that the increase in thermal diffusion tests shows that the state attaches great importance to the safety issues in the use of terminals. Thermal diffusion tests test the thermal management control level of power battery companies, which increases the threshold for the detection of power core and its battery pack.

The more pertinent suggestion is to retain the most controversial test criteria and refine their clearance levels. For example, acupuncture testing can set the level of testing according to specific battery material systems, core energy density, charging and discharging voltage, etc., similar to the waterproof IP level in electronic products, and make detailed horizontal division of each power battery product., Subsidies are then set according to the level of the senior level.

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