According to the national standard management procedure, the mandatory national standard (GB 17761-2018) of technical code for safety of electric bicycles, which was revised by the Ministry of industry and information technology, was approved and issued by the State Administration of market supervision and administration and the National Standardization Administration, and officially implemented on April 15, 2019.


The new national standard has greatly adjusted the technical requirements for electric bicycles


Added tamper proof requirements to prevent the product from being illegally modified after leaving the factory;

The maximum speed was increased from 20 km / h to 25 km / h;

The motor power is increased from 240W to 400W;

The mass of the whole vehicle including battery is adjusted from 40kg to 55kg

Strengthen the riding ability requirements, electric bicycle must have the function of pedal riding.

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Source: Ministry of industry and information technology of SMM


This standard emphasizes the non motorized properties of e-bikes in terms of speed and weight, especially whether they have the ability to ride on foot. It completely distinguishes the previously confused e-bikes and e-motorcycles. In terms of use, e-bikes and e-motorcycles will be subject to more stringent traffic regulations than e-bikes, such as e-motorcycles It is necessary to have a motor vehicle license, drivers are required to hold a driver's license, and can only drive in the motorway, which will greatly help to improve the traffic order and reduce traffic accidents. From this point of view, the new national standard for electric bicycles has laid a standard for the long-term healthy development of the electric bicycle market.


In the new national standard for electric bicycles, the maximum weight of the whole vehicle is limited to no more than 55 kg. Although there is no explicit prohibition on the use of lead-acid batteries, the actual upper limit stipulates that lead-acid batteries can only be used in electric bicycles with short driving range, objectively encouraging everyone to use lithium batteries. The harm of lead-acid batteries to the environment has been a consensus. Last year, some deputies to the National People's Congress proposed to ban the use of lead-acid batteries. At present, China produces more than 32 million e-bikes every year. However, due to the high purchase cost of lithium batteries, the current penetration rate is less than 12%. The release of the new national standard will accelerate the application of lithium batteries in e-bikes. In fact, since the service life of lithium batteries is more than 2-3 times that of lead-acid batteries, the average cost of lithium batteries has been equivalent to that of lead-acid batteries. With the release of lithium battery capacity, the cost still has 30-40% space to decline in the next three years. Therefore, it can be predicted that lithium batteries will occupy most of the market of electric bicycles in five years.


Compared with lead-acid battery, lithium battery is easy to be damaged under over-voltage, under voltage, over-current, over temperature and other conditions. Therefore, lithium battery must be equipped with corresponding charging management circuit and monitoring and protection (BMS) circuit in order to use safely. The extensive use of lithium batteries in electric bicycles and motorcycles will surely drive the rapid growth of the demand for lithium battery BMS system. The new national standard of electric bicycle stipulates that the nominal voltage of storage battery is ≤ 48V and the maximum output voltage is ≤ 60V, which stipulates the maximum number of cells in series of electric bicycle: 48 / 3.0 = 16 (the nominal voltage of LiFePO4 battery cells is usually 3.0V or 3.2V). If ternary or manganese lithium batteries are used, the maximum number of cells in series is 48g3.7 = 13, and the number of cells in series commonly used in the market is 7, 10, 13, 15 and 16. The pure hardware lithium battery protection scheme has the advantages of low cost and flexible use. At present, it is the mainstream scheme of electric bicycle BMS system.


Due to the lack of pedal riding ability, according to the new national standard of electric bicycle, the previously popular electric scooter will be classified into the category of electric motorcycle. Therefore, the market proportion of electric motorcycles will increase significantly in the future. In terms of the development of battery management system, combined with the national recommended standard for lithium-ion batteries for electric motorcycles and electric mopeds (gbgt) issued in September 2018 and implemented on April 1, 2019 36672-2018, not yet enforced) stipulates that the electric motorcycle should be able to collect and save the data of voltage, temperature, total battery voltage, current, charging and discharging times and maximum charging current of single cell, which requires the BMS system of electric motorcycle to have the ability to collect voltage, current and temperature. The pure hardware protection scheme can not meet this requirement, so it has the advantages of high reliability The battery monitoring scheme with analog front-end and protection function will be more widely used. The national recommended standard of lithium-ion batteries for electric motorcycles and mopeds requires that the communication between battery management system and vehicle controller, motor controller and charger should adopt can communication protocol. Therefore, electric motorcycles will adopt more can drivers and isolators in the future, and corresponding isolation power supply should be provided for this purpose. The new national standard of electric bicycle does not have these requirements, so the electric motorcycle will adopt a more complex BMS system than the electric bicycle. At present, most electric scooters and motorcycles still use lead-acid batteries. Although GB / T 36672-2018 does not limit the use of lead-acid batteries in terms of weight, the current lead-acid battery management system usually does not have the ability to collect voltage, current, temperature and communication. Lithium batteries still have advantages in meeting the requirements of national standards. GB / T 36672-2018 also recommends the rated voltage of electric motorcycle battery, 48V / 60V / 72V / 84v / 96V / 144v. At present, the mainstream in the market is 48V / 60V / 72V, so the number of commonly used batteries in series is 13, 16, 17, 20 and 24.



To sum up, the impact of the implementation of the new national standards for electric bicycles and motorcycles on the market is mainly reflected in:


Lithium batteries will replace lead-acid batteries and become the mainstream of batteries for electric bicycles and motorcycles

Electric scooters will be included in the category of electric motorcycles, thus increasing the total market volume of electric motorcycles

Due to the requirements of the new standard for electric motorcycles (not yet enforced), the lithium battery management scheme with single cell voltage, temperature and other information sampling ability will be the mainstream

Due to the requirements of the new standard for electric motorcycles (not yet enforced), can bus will be widely used, and the corresponding high voltage DC-DC with isolation and low static power consumption will also be widely used

The following is the typical system block diagram of BMS system for battery pack of electric bicycle and motorcycle. Except for the battery marked in gray, temperature, current detection resistance and fuse (the chip marked in yellow is optional function), Ti can provide complete solutions for electric bicycle and motorcycle, and has been recognized by the majority of brand customers.