Lithium batteries are really more dangerous than lead-acid batteries?

by:CTECHi     2021-07-10

Is lithium batteries really more dangerous than lead-acid batteries? This is not the case.

Since we understand why batteries explode, which one is safer, lithium batteries or lead-acid batteries?

In terms of battery structure, the current lithium battery packs are basically 18650 batteries for packaging, while lead-acid batteries are basically maintenance-free lead-acid with good sealing performance If the internal pressure of the battery is too high and the safety valve is abnormal, the risk factors of the two are basically the same.

The safety valve on the top of the 18650 cell

If the battery is overcharged for internal hydrogen evolution, the electrolyte in the 18650 battery The content is quite limited, and the amount of hydrogen released is also extremely limited, but for lead-acid batteries using dilute sulfuric acid as the electrolyte, if overcharge occurs, the hydrogen evolution inside the battery is serious, and the probability of deflagration is greatly increased.

In the case of severe damage to a certain brand of lithium battery pack, the safety valve was activated to release the pressure, and no fire or explosion occurred.

From the perspective of battery safety protection, 18650 batteries are designed with safety valves, which can not only release excessive internal pressure, but also physically disconnect the battery from the external circuit, which is equivalent to physically isolating the battery to ensure the battery Pack the safety of other batteries. In addition, lithium battery packs are usually equipped with a BMS protection board, which can accurately control the state of each cell in the battery pack and directly solve the problem of overcharge and overdischarge from the root cause.

BMS can solve the problem of overcharge and overdischarge of lithium battery cells to the greatest extent

On the contrary, lead-acid batteries In terms of safety protection, except for the safety valve, there seems to be lackluster. BMS protection is almost non-existent. Many inferior chargers cannot even be powered off after being fully charged. Safety protection is far from lithium batteries.

Lead-acid battery lacks BMS system protection

With a low-quality charger, it is your good character if you don’t have an accident

Of course, if you use a lithium battery whose price is similar to that of a lead-acid battery, no one can save you in this situation.

Finally, if the battery structure is damaged due to an accidental collision, lead-acid batteries seem to be safer than lithium batteries. However, in this level of accident, the battery material has already been exposed to the open environment, and there is no way to talk about an explosion.

Summary: The battery is not a bomb explosion, it is more caused by inferior products

From the perspective of the safety and redundancy design of the battery, Qualified lithium batteries and lead-acid batteries can fully guarantee the safety of users, and there is no obvious safety difference.

However, due to the large number of low-end small electric vehicles and scooters on the market, and most of them use poor-quality lithium batteries, they are relatively more prone to accidents. It also leaves consumers with the illusion that lithium batteries are not safe.

Take ten thousand steps, if lithium batteries are really so dangerous, why do most of the world's electric vehicles choose lithium batteries as their power source?

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