Review expert: Luo Huachun
Editor-in-Chief of Cities and Disaster Reduction
In Beijing, where road congestion is getting worse, no matter how fast the car is, it may not be as fast as an electric bicycle, so an electric bicycle has become the first choice for many friends.
Source: Tencent News
With the increasing popularity of electric bicycles, the safety hazards of electric bicycles have also become a hot spot of everyone's attention. Although with the release of the "new national standard" and the implementation of the electric bicycle licensing system, the use of electric bicycles is becoming more and more standardized, but the number of ownership continues to rise, and deflagration accidents occur from time to time, which makes electric bicycles the protagonist of many accidents.
According to the statistics of the National Fire and Rescue Administration, a total of 21,000 electric bicycle fires will be reported nationwide in 2023, an increase of 17.4% compared with 2022. Why is an electric bicycle so "flammable and explosive"? Let's start with its "core".
The deflagrated nuclear "core" - lithium battery
On April 15, 2019, the mainland officially implemented the "Safety Technical Specifications for Electric Bicycles", which is also known as the "New National Standard", which makes clear provisions on a series of parameters of electric bicycles:
1. The speed of the vehicle shall not exceed 25KM/h
2. The weight of the vehicle does not exceed 55KG
3. The battery voltage does not exceed 48V
4. The rated continuous output power of the motor does not exceed 400W
5. There is a pedal and can be pedaled and ridden
6. The power is electric drive or electric power
According to the relevant provisions of the "New National Standard", lithium batteries have become the most suitable electric "core" for electric bicycles by virtue of their lighter weight, higher energy density and longer life.
The lithium battery we are talking about now is a lithium-ion battery, which is a battery that uses a metal compound containing lithium as the cathode material, graphite as the anode material, and a non-aqueous electrolyte solution. This is a reusable battery (rechargeable battery) that is widely used in mobile phones, laptops, e-bikes, electric vehicles.
Source: NetEase News
Lithium batteries are still active in all aspects of life, but it is not a good partner for "emotional stability", if we can't treat it scientifically, we will also become its "flammable and explosive" victims.
Why are lithium batteries "flammable and explosive"?
Lithium batteries have many advantages, but they have one of the biggest drawbacks, which is "emotional instability". The reason for this "character shortcoming" is "lithium dendrite".
Lithium is a very reactive metal, so active that it can set a fire to anyone you touch. Although developers have been improving the safety of lithium batteries in various ways, short circuits, overcharges, overdischarges, and high temperatures at the positive and negative electrodes may still make lithium ions enter "excitement" again from a stable state.
来源|搜狐
In the process of repeated charging and discharging of lithium batteries, lithium metal will inevitably precipitate, and these precipitated lithium will gradually be deposited to form lithium dendrites, which will penetrate the separator when they reach a certain extent, resulting in a short circuit inside the battery, causing the temperature and pressure of the lithium battery to rise continuously, and finally deflagration.
How to settle the "temper tantrums" of lithium batteries?
The temper of lithium battery is not good, but we can still live in harmony with it when used scientifically and reasonably.
The first thing is to charge when someone is supervised during the day, do not place the charged electric vehicle in the corridor and escape passage, do not modify or buy unqualified electric bicycles at will, and strengthen the daily inspection work.
Source: Popular Science China
So if the lithium battery has begun to "get angry", how can we make it "calm down" earlier?
1. Cut off the power supply
2. Prevent flammable materials
3. Sprinkle water on the unit
4. Do not attempt to remove, pick up, or move the unit.
With the increasing demand for e-bike commuting, its safety issues have also attracted widespread attention, and there have been proposals to revise the "new national standard", such as increasing the maximum weight of e-bikes, ensuring battery capacity, and increasing safety technology.
It is reported that the University of Science and Technology of China and Jinan University have developed a high-precision optical fiber sensor inside the implantable battery, which can monitor the battery status in real time and avoid potential safety hazards such as deflagration. The progress of science and technology has made the "temper" of lithium-ion batteries better and better, and our travel safety has been more guaranteed.
Are you an e-bike traveler?
Don't forget to take care of your "grumpy" friend in the car