Application Watch: Greater rate & cycle performance improvement target in automotive Li-ion batteries

China suppliers of Li-ion batteries for electric and hybrid vehicles plan to switch from graphite anode material to graphene composites.

The electric and hybrid vehicle market continues to grow at a fast pace, and is projected to outsell its traditional gas-powered counterpart by 2040. To benefit from this development, makers of Li-ion batteries are aiming for higher energy density, and better rate and cycle performance.

Based on current battery technology, EVs and HEVs have a limited mileage of 400km per charge, but this can rise to 600 to 800km in the next two or three years with further improvements in energy density. The target for Li-ion units is 300Wh/kg in 2020, more than 400Wh/kg in 2025 and 500Wh/kg in 2030.

China battery suppliers are confident they will be able to keep up with these goals, having already reached 260Wh/kg.

They are also working on increasing electrical conductivity and pressed electrode density to bolster rate and cycle performance. To do this, companies have zeroed in on substituting graphite anode material with graphene composites. Zhuhai Carbon Composite Poly is among those that have introduced such Li-ion batteries. The units have 3.2V nominal voltage and require standard charging of about seven hours.

Adoption of graphene composites, however, is still at the initial stage due to the input's commercialization issues. The material is still an alternative, use of which adds to the battery price.

Simultaneously, solid-state lithium batteries have attracted the attention of China manufacturers. There have been breakthroughs in this line such as those achieved by the Ningbo Institute of Materials Technology & Engineering, CAS and the Shanghai Institute of Ceramics, CAS.

From this, some midsize and big companies, including Dongguan Large and Qingtao (Kunshan) Energy, have started industrializing the battery type. More suppliers are expected to follow once the high technology threshold and cost have been hurdled, and demand picks up.

Application-driven growth

High capacity, enhanced discharge performance at low temperatures, short charging period, long cycle life, light weight and environment friendliness make Li-ion batteries the optimal power source for EVs.

The lithium category is set to continue enjoying robust demand, which is predicted to rise by 15 to 20 percent in the next one or two years. By 2024, it will have a market scale of $18.8 billion, from the estimated $7.3 billion in 2019, according to the Quanzhan Research Institute.

This has been encouraging makers to boost output and invest further in the line. Shenzhen HuaGreen Technology Co. Ltd added production and test equipment, and raised yield by 30 percent. It is confident of sustaining sales growth at more than 20 percent in 2020.

Mainstream Li-ion types

Widely available kinds of Li-ion batteries for EVs and HEVs are LiFePO₄, LiNiMnCoO₂ or NMC and LiNiCoAlO₂ or NCA. These come in cylindrical and square forms, and are designed to support an operating temperature range of -40 to 55 C and a life span of 500 to 2,000 cycles.

All products have built-in protection against overcharging, -discharging, excessive currents and high temperatures. Most are CE-approved, RoHS-compliant and UL-listed.

China makers source anode and cathode materials, separators and cases from local or foreign providers, depending on customers' requirements.

For separators, the usual foreign sources include Asahi, Celgard and Tonen, and their domestic counterparts Cangzhou Mingzhu, Semcorp and Anhui Ryan.

The costs of materials and components have remained steady, keeping product prices from fluctuating. Some companies, however, lowered their quotes to attract more orders.

In the year ahead, no significant cost and price changes are expected.

Industry consolidation in the offing?

With steeper performance requirements on Li-ion batteries used in EVs, local makers focusing on low-end types may eventually be forced out of the line or taken over by large players.

At present, more than 80 percent of China's total installed capacity for this application market comes from top 10 battery makers. Counting the leading 20, the share goes up to as high as 92 percent.

Based on 2018 statistics from the Qianzhan Research Institute, Dongguan Large accounted for 41.21 percent, followed by BYD with 20.33 percent and Guoxuan High-Tech with 5.32 percent.

China's main Li-ion battery production bases for the EV and HEV market are in the Pearl River Delta and the Yangtze River Delta regions, and the Bohai Bay Rim Economic Region.

Over 90 percent of the suppliers gather here, with greater concentration in the cities of Shenzhen and Dongguan in Guangdong province, Changzhou in Jiangsu, Ningbo in Zhejiang, and the Tianjin municipality.

The products in this gallery have been handpickedby our China-based market analyst for representing current trends in Li-ion batteries from China makers.

Li-ion battery with 7, 15, 16Ah rated capacity

Camelion Enterprises Ltd's model FSC7 Series Li-ion battery has 48V nominal and 54.6 or 54.75V limited charge voltage, and 7, 15 or 16Ah rated capacity. The unit with built-in overcharge, -discharge, -current and -temperature protection has a standard charging time of 3 to 5 hours. The life span of the LiFePO₄ variant is 2,000 cycles and that of the NCM type more than 500 cycles.

The 10-unit minimum order has a delivery lead time of 25 days.

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8.6 to 12Ah Li-ion battery

This 46.8V Li-ion battery with 8.6 to 12Ah capacity and ≤160mohm internal resistance from Shenzhen HuaGreen Technology Co. Ltd, HG4103 model, has built-in overcharge, -discharge, -current and short-circuit protection. The 200x120x72mm unit weighing 180g has 0 to 45 C charge and -20 to 60 C discharge temperatures. It meets GB/T18287-2013 requirements.

An order of at least 50 units is required. Delivery lead time is 7 days.

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3.2V, 200Ah Li-ion battery

Model 80170615P-200AH Li-ion battery from Soundon New Energy Technology Co. Ltd has nominal voltage and capacity of 3.2V and 200Ah, and standard charge and discharge current of 60 and 100A. The unit with overcurrent, -heat, -charge and -discharge protection lasts 2,000 cycles. It supports charge and discharge temperatures of 0 to 45 C and -20 to 50 C.

The minimum order of 10 units is delivered within 20 days.

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Li-ion battery has 114.7Wh rated power

From Zhejiang Gushen Energy Technology Co. Ltd, the model GSNCM46160M-31-EV-02 Li-ion battery has a rated voltage, capacity and power of 3.7V, 31Ah and 114.7Wh, and impedance of 1.5mohm. The 670±10g unit has standard charge rate and current of 1C and 31A. At maximum, the continuous discharge rate and current are 4C and 124A, and the instant discharge rate and current 10C and 310A.

An order of at least 12 units is for delivery within 10 days.

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