Recently, the mandatory national standard of "Safety Technical Specifications for Lithium-ion Batteries for Electric Bicycles" was released and will be officially implemented on November 1, 2024.
The "Technical Specification" stipulates the safety requirements and test methods for lithium batteries for electric bicycles applicable to the "Safety Technical Specifications for Electric Bicycles" (GB 17761) from the two levels of single batteries and battery packs. Among them, the single battery mainly considers six safety requirements: overcharge, overdischarge, external short circuit, thermal abuse, acupuncture, and marking; The battery pack mainly considers 22 safety requirements in 7 aspects, including electrical safety, mechanical safety, environmental safety, thermal diffusion, mutual recognition and collaborative charging, data collection, and marking.
At present, the social ownership of electric bicycles in mainland China has exceeded 350 million, and in 2023, enterprises above designated size in the country will produce a total of 42.28 million electric bicycles. There are two main types of batteries used in electric bicycles: lead-acid batteries and lithium-ion batteries. Among the new models of electric bicycles released by major domestic electric bicycle brands, the proportion of lithium-ion batteries has exceeded 20%.
As a mandatory national standard for the safety of lithium-ion batteries for electric bicycles, the Technical Specifications are of great significance for standardizing the design, production and sales of lithium-ion batteries for electric bicycles, improving product quality and safety, and will promote the healthy and orderly development of the electric bicycle industry.
Technical Specifications
Which vehicle batteries are suitable for?
It is only applicable to lithium-ion batteries for electric bicycles with a maximum output voltage of no more than 60V as specified in GB 17761 "Safety Technical Specifications for Electric Bicycles".
Lithium-ion batteries are not suitable for use in electric scooters, balance bikes, electric motorcycles, electric tricycles, etc.
What are the common lithium-ion batteries?
Can high-nickel ternary lithium batteries still be used?
Common lithium-ion batteries for electric bicycles mainly include lithium manganese oxide batteries, lithium ferrous phosphate batteries and ternary lithium batteries. Among them, ternary lithium batteries can be divided into nickel-cobalt-manganese batteries with high nickel systems, nickel-cobalt-aluminum batteries and nickel-free lithium manganese iron phosphate batteries.
The "Technical Specification" stipulates strict overcharge (1.5 times), acupuncture and other tests for single batteries, and it is difficult for high-nickel ternary lithium batteries to pass the above tests, and it will be difficult to be used in the field of electric bicycles in the future.
Q: What is the overcharge test?
In layman's terms, battery overcharging is the continuation of charging the battery after it has been fully charged. Qualified batteries should not catch fire or explode.
Source: "Weekly Quality Report"
In the overcharging experiment of Jiangsu Fire Department, the flame temperature can rise to about 1200°C about 3 minutes after the electric bicycle catches fire. Once the "thermal runaway" of the e-bike battery occurs, the combustibles in the body will be fully burned until the chemical reaction is completed during the combustion explosion process.
Q: What is acupuncture test?
Battery acupuncture test is a mainstream battery destructive experimental method. After the battery is fully charged, the battery cell is pierced with a steel needle with a diameter of 3 mm and left for 30 seconds to verify the safety and stability of the battery. Qualified batteries should not catch fire or explode.
Qualified lithium iron battery puncture test. Source: Beiqing Net
Unqualified ternary lithium battery puncture experiment. Source: Beiqing Net
All e-bike batteries
Do they all have to comply with the Technical Specifications?
According to Article 25 of the Standardization Law of the People's Republic of China, "products and services that do not meet the mandatory standards shall not be produced, sold, imported or provided." Therefore, after the implementation of this standard, the lithium-ion batteries for electric bicycles sold in China must meet its requirements.
Why is it required
Mark the safe life of the battery?
With the increase of service life, the capacity of lithium-ion batteries gradually decreases, and the existing safety risks will gradually amplify. The "Technical Specifications" require manufacturers to mark the "safe service life" on the battery pack, remind users to eliminate old batteries when they expire, reduce the potential safety risks caused by old batteries, and protect the safety of users' lives and property.
The inspectors put two new batteries that had been disassembled separately and used for a long time into the experimental box at the same time, and carried out the charging test at a fixed temperature and under the same conditions. The test results showed that the temperature of the aging battery rises faster than that of the fresh battery, with an average of 1-2 degrees higher.
How consumers buy
Lithium batteries that comply with the Technical Specifications?
When purchasing an electric bicycle, consumers can confirm whether the battery meets the "Technical Specifications" by checking the nameplate, specifications, instructions for use and other information of the battery, or asking the seller to request the corresponding "Technical Specifications" test report or certification certificate of the product.
Source: National Emergency Broadcasting Comprehensive CCTV News Client, Ministry of Industry and Information Technology, Weekly Quality Report, Beiqing Net