Lithium ion battery is one of the important core components of electric vehicles, and most of them are assembled in the dirty and low position of the vehicle chassis, so the protection level of lithium ion battery is also the highest in the whole vehicle. In recent years, it is common to hear electric vehicle manufacturers in the advertising of the IP67 standard, in fact, refers to the dust and water resistance levels of lithium-ion batteries.

What is lithium-ion battery protection grade IP67?

  Measuring the dustproof and waterproof performance of batteries has an index called intrusion protection, is drafted by IEC (International Electrical Works Commission), referred to as IPXX, the first X represents dustproof (solid) grade; The second X represents the waterproof (liquid) rating. IP67 solid state protection level reached 6, completely prevent foreign objects and dust; Liquid protection level reached 7, short soak to prevent water invasion.

  It can be seen that the higher the value, the higher the level of protection. The IP67 protection level means that an object can enter water at a depth of 1m for 30 minutes without affecting its performance, which is a relatively high level of protection. So when it rains or goes over a puddle, there is no problem with electric cars.

  In terms of the tightness of lithium-ion batteries, the national requirements must meet the IP67 standard. IPXX is a protection safety level that describes the ability of an object to resist dust and water. It is used to describe the protection ability of an interface against liquid and solid particles. There are two numbers in the IP standard, where the first number represents the dustproof ability of the object, and the second number represents the waterproof ability. These two numbers start from 0, among which there are 7 levels of dustproof ability and 8 levels of waterproof ability. The larger the number, the higher the protection level.

  Although the waterproof performance of lithium-ion batteries is very high, it is not recommended to wade into water easily. On the one hand, the battery protection level reaching IP67 is not equal to the protection level of other parts of the vehicle also has IP67. If the water level is high enough, the water will overflow into the car from the gap, causing water inside the car to damage or short circuit the low-voltage electrical appliances; On the other hand, the underwater situation is complex, the vehicle wading will be due to turbidity of water and other reasons, can not see the underwater situation, resulting in battery shell support or scratch, damage to the battery, resulting in battery water or short circuit caused by extrusion and puncture, causing combustion accidents.

How does power Lithium battery prevent collision protection?

  In the collision accident of pure electric vehicle, the power lithium battery is impacted and squeezed to cause deformation, and the battery core may have thermal runaway fire. Other components in the battery pack may also be squeezed and impacted in the collision, which may cause short circuit or even fire and explosion. High-voltage cables and components inside battery packs are easily scratched or torn during a collision, which may cause a short circuit fire or electric shock.

  The key of power lithium battery collision protection is to control the deformation of the battery shell structure during the collision, and try to prevent the internal components from being impacted and squeezed. In addition, the battery core and high voltage components themselves should also have certain extrusion resistance and puncture resistance. In recent years, some researchers have studied some buffer structures, which can absorb part of the impact energy during the collision to ease the acceleration impact of the battery pack. This may have a positive use in terms of battery pack durability, but it doesn‘t mean much in terms of battery pack collision protection.

  To strengthen the safety of power lithium batteries and prevent deflagration of batteries due to collisions, we can start from the following aspects:

1. Strengthen battery protection:

  New energy vehicles should choose the exclusive platform as the vehicle platform to prevent the continued use of the "oil to electricity" platform, so that the position of the power lithium battery pack can be moved from the trunk and other vulnerable positions to the vehicle chassis, in order to reduce the probability of the power lithium battery being hit.

2. Pay attention to safe driving:

  When driving, drivers should pay attention to safe driving to prevent traffic accidents. Do not easily open the car on the curb, the vehicle over the pit must slow down, to prevent the vehicle bottom, so that the battery damage.

3. Strictly control battery quality:

  Battery manufacturers must strictly control the quality of batteries and prohibit the introduction of batteries that are not fully certified into the market. Must be in accordance with the requirements of national standards, the battery immersion, extrusion, collision, puncture, combustion and other safety tests, and pass before entering the market.

  The key of power lithium battery collision protection is the response time of the system to the collision accident, that is, the time from the collision to the vehicle breaking voltage. The shorter the response time, the more favorable the protection of users and batteries. The collision protection system needs a certain processing time, including the time of receiving the collision signal, confirming and controlling the action of the corresponding equipment.

  That‘s what lithium-ion battery protection class IP67 means and how power lithium-ion batteries prevent collision protection. Higher levels of protection mean higher manufacturing costs for manufacturers, especially since liquid intrusion protection is so complex that IP67 protection is now common for high-voltage components of lithium-ion batteries, including some smartphones that claim to be "waterproof."