Electric vehicle power lithium batteries primarily refer to various types of batteries used as the power source for electric vehicles in homes and similar settings. They are mainly classified by material, including lead-acid batteries and lithium-ion batteries. They are also classified by application, including lithium batteries for household electric vehicles and lithium batteries for electric vehicles used in special applications. Currently, the electric vehicles people encounter and use daily are almost all electric bicycles; therefore, the power lithium batteries used in electric bicycles are often simply referred to as electric vehicle batteries, which is the general understanding of electric vehicle power lithium batteries.
Currently, electric vehicle power lithium batteries are mainly divided into two categories: lead-acid batteries and lithium-ion batteries. In my country, lead-acid batteries are products subject to production license management, and production can only proceed after obtaining approval from relevant departments. The products must be marked with a production license and the QS mark. Lead-acid batteries are a traditional power source for electric vehicles, and their application in electric vehicles has been over 20 years. The product technology is quite mature, with an application rate of over 98%. Lead-acid batteries used in electric bicycles generally consist of several 12V battery cells, forming battery packs with voltages primarily of 36V and 48V, and a capacity not exceeding 20Ah.
Lithium-ion batteries have been used in electric vehicles for less than 10 years, and as a new energy product, their technology is not yet perfect, and their safety performance needs to be improved, resulting in a relatively small application range. The main positive electrode materials for lithium-ion battery cells used in electric bicycles are lithium manganese oxide, lithium iron phosphate, and ternary materials. The casings are primarily made of steel or aluminum, and the shapes are mainly square soft-pack, square hard-pack, and cylindrical.
my country's lead-acid battery production is mainly concentrated in Zhejiang, Jiangsu, Hebei, Guangdong, Hubei, and Shandong provinces, which account for more than 90% of the country's lead-acid battery production. Before 2011, there were more than 1,200 companies nationwide with lead-acid battery production licenses. After environmental protection rectification since 2011, about 300 companies are now in normal production.
After years of development, my country has basically formed two major production bases for lead-acid lithium-ion batteries for electric vehicles, mainly in Jiangsu and Zhejiang provinces. Currently, Tianneng and Chaowei, two companies in Changxing, Zhejiang alone, account for more than 70% of the national output of this type of battery.
my country accounts for over 30% of the global lithium-ion battery production, and this figure is increasing year by year. In 2011, my country produced approximately 3 billion lithium-ion batteries. The domestic lithium-ion battery industry for electric vehicles is mainly concentrated in the Pearl River Delta, Yangtze River Delta, and Bohai Rim regions, with smaller concentrations in Henan, Fujian, and Harbin. Major manufacturers of lithium-ion batteries for electric bicycles include Suzhou Xingheng, BAK, Tianjin Lishen, ATL New Energy, BYD, and Harbin Guangyu.
In recent years, my country's electric vehicle power lithium battery industry has developed significantly, with a continuous increase in product variety and improvement in quality. Compared with the development of the battery industry abroad, China has creatively developed a new type of battery, the lead-acid battery for electric bicycles, which better meets the travel and consumption needs of the general public. However, at the same time, my country's electric vehicle power lithium battery industry still needs further improvement and development.
The battery industry suffers from low industry concentration. In my country, there were once thousands of companies producing lithium-ion batteries for electric vehicles. Although the industry has undergone consolidation, particularly due to environmental regulations, several hundred companies still exist. Compared to the highly concentrated battery industry abroad, my country's battery companies are numerous but small in scale, remaining fragmented and unable to achieve the scale and concentration of foreign battery companies. Therefore, improving industry concentration is urgently needed.
my country's reliance on foreign technology and equipment, and its dependence on imports for key materials, is a significant weakness. In the area of lithium-ion batteries for electric vehicles, Chinese companies hold a relatively small number of patents related to core battery technologies. Most key technologies are monopolized by Japan and the United States. For example, lithium-ion battery separators are almost entirely imported, and the technology and equipment for producing these separators are listed as subject to export restrictions to my country. Domestic lithium-ion battery manufacturers for electric vehicles are largely dependent on foreign companies producing key materials, resulting in a weak foundation for widespread technological breakthroughs and innovation in battery technology.
As the power source for electric vehicles, the lithium-ion batteries used in electric vehicles must first meet consumers' performance requirements. Furthermore, given that the safety performance of lithium-ion batteries for electric vehicles has not yet been fully resolved, protecting user safety and preventing injury should be a crucial principle and basis. Important domestic standards concerning the quality and safety of lithium-ion batteries for electric vehicles include: GB/T22199-2008 "Sealed Lead-Acid Batteries for Electric Bicycles", GB/T7403.1-2008 "Traction Lead-Acid Batteries Part 1: Technical Conditions", GB/T18332.1-2009 "Lead-Acid Batteries for Electric Road Vehicles", and QB/T2947.1-2008 "Batteries and Chargers for Electric Bicycles Part 1: Sealed Lead-Acid Batteries and Chargers", etc.
Common Important Issues
In recent years, the State Administration for Quality Supervision, Inspection and Quarantine has conducted multiple national supervision and spot checks on lithium battery products for electric vehicles. Key issues discovered during these checks include:
1. Capacity
Capacity is a key performance indicator of a battery, best reflecting its actual performance. Capacity is further divided into 2-hour rate capacity and -15°C low-temperature capacity. The 2-hour rate capacity directly affects the normal driving range of an electric vehicle, while the low-temperature capacity reflects the battery's performance in low-temperature conditions.
The reasons for non-compliance are as follows: On the one hand, some companies have not adequately controlled quality, lack strict methods for product quality control, and lack effective management of employees and production processes. Alternatively, some companies reduce costs in pursuit of higher profits or cut corners to compete on price. On the other hand, some manufacturers or distributors deliberately exaggerate or mislabel battery capacity to increase profits, selling smaller capacity batteries at larger capacity prices. The latter constitutes misleading or deliberate deception of consumers and disrupts the order of the battery market.
2. Charging acceptance capability
Charge acceptance refers to a battery's ability to be charged under certain conditions. While it superficially reflects the battery's charging efficiency, it is actually greatly influenced by the battery's grid alloy composition, lead paste composition, additives, electrolyte, and even its structure and assembly quality. In a sense, charge acceptance also affects the battery's capacity and cycle life.
3. Over-discharge
Over-discharge refers to a battery continuing to discharge beyond its discharge termination voltage. At this point, the electrolyte concentration becomes extremely low, leading to a significant increase in the concentration of lead sulfate produced by the chemical reaction. This lead sulfate crystallizes into larger particles, forming sulfation. These crystals have poor conductivity and large size, clogging the micropores of the electrode plates. Over time, this prevents the reversible conversion of electrical and chemical energy, or causes electrode grid deformation, active material shedding, and short circuits in individual cells. Consequently, batteries that have undergone discharge testing exhibit poor recharge recovery capabilities, resulting in severe damage to the battery, or even irreparable damage.
In the daily use of electric vehicles, consumers often leave the vehicle parked for a period of time after it stops due to insufficient power, instead of charging it in time. This causes the battery to be in an over-discharged state, which is very damaging to the battery and will affect its lifespan.
Purchase and usage tips
1. Are the product labels complete?
This includes the manufacturer's name, product model or specifications, manufacturing date, trademark, and production license mark and number; for lead-acid batteries, check whether the product itself has a prominent production license mark and number, and try to choose products with a production date close to the purchase date.
The larger the battery capacity, the longer the battery discharge time. Do not buy batteries without capacity markings. If the battery has multiple capacity markings, consult the relevant department to confirm and beware of being deceived by false capacity markings.
Check if the markings on the battery itself match those on the outer packaging.
When purchasing batteries separately, be sure to request a formal invoice to protect your legal rights in case of disputes.
2. Battery appearance
Check for deformation, cracks, scratches, and signs of leakage. The battery terminals should be clean, free of rust, and the markings should be clear.
3. Develop good usage habits
When using an electric vehicle, it is best to use manual assistance to start it, especially when starting or going uphill against the wind. When starting, going uphill, or riding against the wind in strong winds, use pedal assistance to reduce battery load and extend its lifespan. When going downhill, the throttle can be released. When the battery is low, ride at a lower speed and do not continue riding with the battery in a low-voltage state.
Overloading an electric vehicle will cause the battery to discharge with a large current for a long time, thereby damaging the battery, which is one of the important reasons for the shortened battery life.
4. Master the correct charging method
The ideal operating temperature for the battery is between 0-40℃. Charging should ideally be done at room temperature, especially in cold weather. Pay attention to the charger's charging status and normal charging time to prevent undercharging or overcharging. If any abnormal charging is detected, consult a professional immediately to avoid damaging the battery. Charge the battery promptly after each use. If the battery is to be stored for an extended period, charge it periodically.
5. Use the charger that comes with the battery.
Using a battery charger that is compatible with the lithium-ion batteries used in electric vehicles is crucial. A suitable charger can automatically adjust the charging process based on the battery characteristics, which helps extend the battery's lifespan. For lithium-ion batteries used in electric vehicles, the manufacturer-specified charger must be used; when the battery pack is replaced, the charger must also be replaced.
6. Regularly maintain and replace the battery.
If the battery charge is low after prolonged use, especially if the battery gets very hot during charging, you should have it checked by a professional repairman. If necessary, replace the battery. When replacing batteries, the entire set should be replaced at the same time.
Batteries of different models or ages should not be connected in series or used simultaneously, and batteries from different manufacturers should not be mixed.
7. Pay attention to product quality testing information released by relevant departments.
Consumers can regularly pay attention to product quality monitoring information released by relevant regulatory authorities and learn about battery selection, use, and maintenance knowledge through various information sources.
8. Rational recycling
Lead and lead oxides pollute the environment and endanger the health of the human nervous system, digestive system, hematopoietic system, kidneys, and other systems. Lithium-ion batteries contain toxic substances such as lithium hexafluorophosphate, which pollute the environment and ecosystems. Heavy metals such as cobalt, manganese, and copper can also harm humans through the food chain by accumulating and being used in other applications. Therefore, discarded lead-acid and lithium-ion batteries used in electric vehicles should not be randomly piled up, discarded, or dismantled. They should be handed over to the manufacturing company or specialized recycling organizations for recycling.
