1. Power Battery Technology Roadmap
Power batteries are batteries that provide energy to the power system of electric vehicles, and mainly include lithium-ion batteries, nickel-metal hydride batteries, and lead-acid batteries.
(1) Different battery types and technical routes a. Lead-acid batteries have certain advantages in mild hybrid and urban pure electric vehicles due to their good safety and low cost. However, due to their low energy density, they cannot be used in other types of electric vehicles.
b. Nickel-metal hydride (NiMH) batteries are a mature and safe technology, and have dominated the hybrid vehicle market in recent years, especially in mild, medium, and severe hybrid models. However, due to their low energy density and high cost, their technological development is nearing its limit, leaving little room for further performance improvements.
c. Lithium-ion batteries have excellent performance, a wide range of applications, and promising prospects, and will gradually occupy a mainstream position in the future market. However, due to safety and cost issues, they are currently still in the development stage.
(2) Lithium-ion battery technology route The positive electrode materials of lithium-ion power batteries mainly include lithium manganese oxide, ternary materials and lithium iron phosphate.
a. Lithium manganese oxide has good safety and low cost, but poor high-temperature performance and short lifespan.
b. Ternary materials have high energy density and relatively balanced performance, but their cost is relatively high.
c. Lithium iron phosphate has the best safety and long cycle life, but its low-temperature performance is poor and its energy density is low.
Currently, most foreign battery companies, such as Panasonic, Sanyo, SBL, LG, and JCS, primarily choose lithium manganese oxide and ternary materials; while most domestic battery companies and the American company A123 primarily choose lithium iron phosphate. In the near term, lithium manganese oxide and ternary materials are more mature and will be the first to be industrialized. In the long term, lithium iron phosphate is likely to gradually occupy the mainstream position in the future market.
2. Development Status Abroad
(1) Major foreign material companies have advanced technology, possess relevant invention patents, have large production scales, and sell materials at high prices. Phostech of Canada owns the original patent for lithium iron phosphate, and its products are priced at approximately RMB 300,000 to 400,000 per ton.
(2) Major foreign battery companies have advanced technology, especially in power batteries, which have good consistency and long service life and can meet the requirements of the whole vehicle, but the cost is high. The Toyota Prius, which has sold more than 2 million vehicles, uses nickel-metal hydride batteries, which have an 8-year warranty in Europe and a 10-year warranty in the United States. The battery cost is about RMB 15 to 21 per Wh.
(3) Foreign automotive giants and professional auto parts companies are increasingly choosing to collaborate with professional battery companies, leveraging the battery companies' expertise in cell manufacturing and combining it with their own capabilities in vehicle or parts electronic control design and system integration to jointly develop power battery systems. For example, Toyota and Panasonic formed PEVE, Bosch and Samsung formed SBL, Nissan and NEC formed AESC, and JCI and SAFT formed JCS. This trend is particularly noteworthy.
(4) The government attaches great importance to the research and development of power batteries and related materials, and actively invests huge sums of money to subsidize enterprises in their development. In 2009, the United States invested US$2.4 billion to support the research and development and industrialization of electric vehicles, mainly involving power batteries, materials and systems. Japan planned to invest 24.5 billion yen over five years starting in 2007 for the research and development of automotive power batteries.
(5) Foreign companies are investing heavily to expand their power battery production capacity. Japanese companies such as AESC plan to invest 100 billion yen and Sanyo plans to invest 80 billion yen; American companies such as JCS plan to invest 220 million US dollars and A123 plans to invest 600 million US dollars to expand the production scale of lithium-ion power batteries.
(6) Foreign institutions and companies have launched next-generation power battery development projects. Japan launched the "Development Plan for Next-Generation Automobiles and Fuels" in 2007, with the goal of increasing the energy density of power batteries to seven times that of today and reducing costs to one-fortieth of current levels by 2030.
3. Current Status of Development in my country
(1) Power battery materials
a. my country has abundant resources of major raw materials for power batteries, ensuring the industrialization of these batteries.
The main raw materials for power batteries include lithium, graphite, rare earth, lead, etc. my country has abundant mineral deposits of these resources, ranking among the top three in the world, which provides an effective guarantee for the industrialization of power batteries.
b. The negative electrode material for lithium-ion batteries has been domestically produced, and the product performance is at an internationally advanced level.
my country's anode materials mainly include natural graphite, artificial graphite, and MCMB mesophase carbon microspheres, with products basically covering the domestic market and some products ranking among the top three in global sales.
c. There are many manufacturers of lithium iron phosphate materials, but few can meet the needs of power batteries.
There are more than 100 companies in China that can manufacture lithium iron phosphate materials, but only a few manufacturers' products can basically meet the requirements of automotive power batteries, and the product stability problem has not been completely solved.
d. Samples of lithium-ion power battery separator materials have been developed, but their performance needs further improvement.
Domestic separator products have partially replaced imported products in the traditional lithium-ion battery market, but all power battery separators are imported, and domestically produced power battery separators are still in the sample development stage.
(2) Power Batteries a. Lithium-ion power batteries have formed a product series, mainly 1-50Ah products. Some manufacturers have developed products above 50Ah, which can support prototype vehicles and demonstration models, but have not yet formed industrial production capacity. Nickel-metal hydride power batteries have also formed a product series, mainly 6-100Ah products, and some products can be matched with mass-produced models.
b. Domestic lithium-ion battery companies have made some progress in technology, especially in safety indicators. However, the technological levels of companies vary, product consistency is poor, and overall there is still a gap compared with international advanced levels, and this gap is likely to continue to widen.
Regarding after-sales service, most domestic lithium-ion battery manufacturers only offer a 1-year warranty, with a few offering a 3-year warranty, while some foreign lithium-ion battery manufacturers offer a 10-year warranty. In terms of price, domestic products have an advantage; the cost of nickel-metal hydride batteries is approximately 10 yuan/Wh, while the cost of lithium-ion batteries is approximately 2.5 to 5 yuan/Wh.
c. Domestic power battery assembly technology is relatively backward, and there is still a large gap before industrialization.
Some manufacturers have already established a certain foundation in battery pack technology and have gained initial recognition from vehicle manufacturers. However, compared with international advanced levels, there are still significant gaps in areas such as thermal management, battery equalization, and space utilization.
d. Domestic enterprises plan to expand investment and actively prepare for industrialization.
In recent years, battery companies have increased their investment in industrialization dramatically. Companies like ATL, Lishen, BAK, and Wanxiang have all planned investments exceeding 1 billion yuan to expand lithium-ion battery production capacity. Hunan Shenzhou, Hunan Keba, and Zhongju Senlai have also planned investments exceeding 500 million yuan to expand nickel-metal hydride battery production capacity. However, most manufacturers are still focusing on developing traditional battery products in the initial stages of their investment.
(3) Battery Management System a. Through research during the "15th Five-Year Plan" and "11th Five-Year Plan" periods, my country has made significant progress in battery management system development.
Some progress has been made in this area, and the product functions are relatively complete, which can support the matching of demonstration models, but it has not yet reached the level of industrialization.
b. Both the battery and vehicle industries lack design and manufacturing experience in battery management systems, resulting in a lack of close cooperation between the two sectors. Domestic battery companies typically outsource the development of related systems to specialized electronics companies or universities, but their research into the internal workings of batteries is insufficient, they lack data accumulation, and they are unable to communicate effectively with design companies, thus impacting product performance.
c. Currently, the product functions are relatively simple. Although it has basic detection and monitoring functions, there is a significant gap compared with foreign products in terms of data acquisition reliability, SOC estimation accuracy, thermal management, equalization, and safety management.
d. Most electronic components are not automotive grade, and due to small batch sizes, they are mostly manufactured by manual soldering, resulting in poor electromagnetic compatibility and low stability and reliability.
(4) Current Status of Power Battery Recycling and Disposal a. The lead and highly corrosive solutions contained in power batteries can cause serious environmental pollution, and waste batteries must be recycled. Moreover, the lead, nickel, rare earth, lithium and other metals and materials in power batteries have recycling value, and waste battery recycling is conducive to resource recycling.
b. Developed countries such as the US, Europe, and Japan have established complete recycling systems. They have not only formulated specific laws and regulations but also established professional and large-scale battery recycling and reuse companies. In contrast, China has not yet established a sound recycling system, and some recycling companies neglect environmental protection, causing secondary pollution.
c. Due to the high requirements of automotive power batteries, although some power batteries cannot provide power to the vehicle, their remaining capacity can still meet the requirements of some energy storage devices. Therefore, adopting a tiered utilization model can expand the application range of some power batteries and reduce usage costs.
4. Major Problems Existing in my country's Power Batteries and Their Management Systems
(1) Due to the difficulty in process control and poor batch stability of lithium iron phosphate materials, the battery manufacturing process is difficult to control, resulting in low cell yield and high cell manufacturing cost. Moreover, the original patent of the material involves core issues that cannot be avoided, posing a significant risk.
(2) As before, the power battery separators are all imported. Domestic power battery separators are still in the sample stage and it is difficult to replace imported products in the short term.
(3) Key production equipment for separators and lithium iron phosphate batteries relies on imports.
(4) The cycle life of the single power battery sample can reach a high level, but due to poor product consistency, the cycle life of the system is greatly reduced after the cells are assembled.
(5) In terms of battery management systems, there is a lack of professionals with expertise in both batteries and battery management systems; the product system functions are simple and the performance is far behind that of foreign products; the product engineering design capabilities are weak and the product reliability is poor.
