Acupuncture test does not perform power battery how to detect safety?

A few days ago, the Ministry of Industry and Information Technology issued three notifications of mandatory standards drafts, one of which was related to GB "Safety Requirements for Lithium-ion Power Battery for Electric Vehicles" (hereinafter referred to as GBXXXXX-XXXX). All the tests for the acupuncture have also undergone major changes.

First look at the requirements of the GB single cell, over discharge, overcharge, short circuit, heating, temperature cycling, extrusion, a total of five safety tests, compared with the 10 test requirements of GB/T31485-2015, reduced by 4 . Among them, the acupuncture requirements for single cells were also canceled in GB.

Let's take a look at how the preparation of the draft commentary explains how to cancel acupuncture. There are three main reasons: first, the provision of access management regulations is not enforced; secondly, the two IEC standards do not use acupuncture; again, acupuncture is considered to be inconsistent with the actual failure mode. There is some less clear information here:

Acupuncture test is not executed for the moment, talk about the safety test of power battery

Let's talk about entry management first. In its Annex 3 new energy automotive product special inspection program and the reference standard, it is indeed stated that "acupuncture test is not executed temporarily", but the reason is not clear. In addition, this is temporarily not implemented. Why is it "temporary" and not "permanent?" Is it possible to resume acupuncture tests in the future? The reason is not clear. This one reason seems to be a bit confusing.

Followed by the IEC does not use acupuncture. This description is less comprehensive. What are the criteria for "etc." In addition to the explicitly mentioned IEC62660-2, IEC62660-3 does not use acupuncture. what about others? In SAEJ2464, UL-2580 (refer to Battery Safety Test (1)) still has acupuncture test requirements. Although FreedomCAR is not a standard rule, it also includes acupuncture as a popular test reference method. In addition, almost all of the qualified internal testing standards of companies have acupuncture requirements before. Therefore, this reason is also not convincing.

The third reason is that acupuncture does not match the actual failure mode. How is it not consistent? If it is said that the need for acupuncture tests can fully replicate the actual failure conditions, this is indeed a very difficult and indeed inconsistent. However, I am afraid that all test requirements are difficult to fully replicate the actual failure conditions. The test conditions only reflect indirectly the conditions of some typical failure modes extracted from the failure modes. Here we talk about "mode", the mode is reproducible, in actual applications, there is indeed a foreign object piercing the battery inside the battery may cause a short circuit. Simply speaking, it seems that there is not enough conviction.

However, what is more interesting is that in the thermal diffusion test of the battery pack in GBXXXXX-XXXX, as for the selection of the recommended triggering method, "acupuncture" has emerged as a candidate method.

The above are some of the less clear places in the draft of the consultation. In retrospect, nowadays the pure electric market is being pushed forward, the battery power is getting bigger and bigger, and the harm degree of battery failure under the same testing conditions is also on the rise, such as 25Ah, 40Ah, 70Ah, even 100Ah NMC square battery, Level may directly go from 3 or 4 to 5. There are indeed some ways to improve acupuncture at the technical level, but often these improvements do not fully account for certain battery performances. Therefore, it takes a certain amount of time to study suitable technical solutions. The greater the energy, the greater the difficulty. The greater the responsibility of the company, acupuncture is not a small hurdle for manufacturers. Some manufacturers may be fortunate to cancel acupuncture, so that the difficulty of getting regulatory certification may be reduced to facilitate the timely delivery of products to customers.

What I want to say here is that although acupuncture was cancelled in the draft, it is necessary to soberly realize that this is only a test required at the level of standards and regulations. It is not necessary to consider the safety and reliability of actual products. Maintain self-discipline, strict requirements, can not give up the study of acupuncture. After all, passing regulatory tests and meeting actual product development needs are two different latitudes. In addition, it also means “temporary” in the admission. Who can guarantee that it will not change in the future, in the future, and in the future? It is a feature of our market that we are advancing in the process of rapid changes, adjustments, and optimization. It is also something that many outsiders cannot adapt quickly.

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