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Frequent Accidents with Electric Cars: China to Tighten the Policy

Date:09-01 17:43 Source:China Auto Think Tank 30 Authour:Ji Wei

Power battery manufacturers including Samsung SDI and LG have all taken the ternary battery route. However, this does not mean the future will be ruled by the ternary lithium battery. The battery industry has always been liable to revolution driven by new materials and technologies. In fact, the whole industry never stops looking for them. Higher energy density and safer performance are always the two ends of a scale that manufacturers try to balance.

Higher energy density and safer performance are always the two ends of a scale that manufacturers try to balance.

Frequent Accidents with Electric Cars: China to Tighten the Policy

On August 16th, a Tesla electric car caught fire. In fact, this was only one of a number of such incidents. The industry says the poor safety performance of batteries is to blame.

The Tesla electric car is a typical example of ternary batteries in application, but their safety performance has always been questioned. It is true that the Tesla electric car has a long range, but more battery capacity often means less safety. “400km is a threshold for electric cars in terms of range,” Dong Yang, Standing Vice Chairman of China Automotive Industry Association, told the 21st Century Business Herald at the China EV 100 Forum.

There has been an ongoing debate in China over whether to use the lithium-ion ferrous phosphate (LFP) battery or the ternary battery. The heart of this debate is whether to put range or safety first, or whether there is any better solution that can combine these two. “Currently, opinions vary on which technical route to choose for electric cars, but it is also up to market development conditions and demand,” said Dong Yang.

According to statistics released by the Ministry of Industry and Information Technology, there have been 31 accidents involving new energy vehicles since 2009. Of these accidents, 17 occurred after 2015, and of the 17 accidents, 4 were caused by faulty battery systems, 6 by associated parts, 2 by defects in the charging system, and 5 by the improper modification or use of cars. As of the end of 2015, the accident rate stood at 0.17‰, more than twice as high as the world average.

Ke Ke, Vice President of Chilwee Research Institute, indicated that Tesla uses the Panasonic lithium battery, which is regarded by many industry insiders as the benchmark of batteries, but the market in China is different from other countries. “In China, in order to reduce initial costs, auto makers prefer to use smaller batteries and tend to extend their use beyond their service life. Therefore, for power battery manufacturers, China is the most challenging market in the world.”

Battery management system standards will be issued soon

In the battery market in China, the LFP battery is relatively safe, but it has a low energy density and that is why there has been a preference for the high-energy-density ternary battery in recent years. However, the safety performance of the latter is yet to be proved.

According to statistics released by testing organizations, a lot of risks are associated with battery cells. Low risks include leakage, deformation and gassing, and high risks include sparking and explosion. If a battery cell suffers from thermal runaway, a ternary battery is more likely to generate sparks than an LFP.

The safety issue of the ternary problem is not something that cannot be fixed. Chen Liquan, Academician of the Chinese Academy of Engineering, said, “A solid-state battery can be much safer if it does not contain an inflammable liquid electrolyte. This is essential to the future of our Chinese lithium batteries. If we miss our chance, we will also miss the opportunity to do research on the lithium sulfur battery and the lithium-air battery.”

At present, more than 4,000 electric cars have been produced by Bellore. The vehicle-carried battery is a solid-state one which uses LFP as the cathode, lithium metal as the anode, and a polymer called PEO in between. In fact, China was conducting studies on this battery as early as 2014, but unfortunately no breakthrough was achieved.

Chen Liquan said, “I suggest providing great support in the research, development and industrialization of solid-state batteries and hopefully industrialization will be achieved within five years.”

The battery cell is one of the factors that affect the safety performance of electric cars; the battery system is another. Probably because the overall design is inadequate, there is no consistent spatial planning for the various components, resulting in the increased accident rate.

According to an investigation, the top 10 manufacturers of new energy spare parts and systems in China do not have uniform standards and requirements for the clearance between a battery module and a battery pack, nor do they have proper and uniform planning for the safety protection of high-voltage electrical components like connectors and cables and of the motor controller.

Li Dong, Director of Department of Equipment Industry under MIIT, said, “the authority has developed the standards for remote monitoring of electric vehicles, and will also issue and implement the safety requirements for electric buses soon. Technical requirements for the battery management system and standards for the coding, specifications and dimensions of power batteries are also under development and revision and will be issued soon. At the same time, the government is also revising the market entry rules for new energy vehicle manufacturers and products by raising higher requirements for the R&D abilities and production conditions of manufacturers as well as for the performance and safety of their products.”

Is it safer to take multiple routes all at the same time?

The government wants new energy vehicle products to target the public transport system and new energy buses as a key field. As of the end of 2015, 86,000 new energy buses had been sold nationwide, year-on-year growth of 136%, of which 36,000 are battery electric vehicles, up by 3.9% on a year-on-year basis, and more than 7,000 are electric taxis, up by 72% on a year-on-year basis. LFP and ternary materials are the major technical solutions for batteries.

On January 14th this year, MIIT issued the Catalogue of Recommended New Energy Vehicle Models, which does not include any electric commercial bus using the ternary battery. Models not listed in this catalogue are not entitled to government subsidies and cannot take advantage of the purchase-tax-free policy. Insiders say this will dampen the enthusiasm of auto makers a lot.

There has been a major trend towards developing high-energy-density batteries. According to statistics, ternary batteries currently hold more than 80% of the global lithium-ion battery market. High energy density is also one of the core technical indicators for batteries specified in our 13th Five-Year Plan. This is the inevitable result of the currently inability of the industrialized electric car range to meet market demand.

Ke Ke said, “We have taken multiple technical routes for batteries, including the material system and the product specifications and models”

As well as safety, increasing range is also the core objective for batteries. Zheng Shixiong, Vice President of Samsung SDI Co. Ltd., says Samsung SDI is exploring potential new materials for the new-generation cell so as to achieve an 800km range.

Power battery manufacturers including Samsung SDI and LG have all taken the ternary battery route. However, this does not mean the future will be ruled by the ternary lithium battery. The battery industry has always been liable to revolution driven by new materials and technologies. In fact, the whole industry never stops looking for them. Higher energy density and safer performance are always the two ends of a scale that manufacturers try to balance.


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