
Traditional lead-acid batteries are flammable and explosive. In fact, most of the reasons are due to improper use. Thanks to more chemical reaction substances and aging technology, the end voltage is higher and the internal resistance is smaller, while the end voltage of the old battery is lower and the internal resistance is larger. The general 12V new battery internal resistance is 0.015-0.018 ohm, but the old battery internal resistance is more than 0.085 ohm.
If the old and new solar batteries are used in series, then in the charging state, the charging voltage at the ends of the old battery will be higher than the charging voltage at the ends of the new battery. As a result, the new battery is not yet full, while the old battery has long gone through high. And in the discharging state, because the capacity of the new battery is larger than the capacity of the old battery. The result causes the old battery to be over-discharged, even causing the old battery to be anti-polar and the battery to bulge causing side effects.
It will consume the electric energy of the new battery, and at the same time, it will cause the voltage inside the appliance to be unstable, and there is also the danger of excessive use of the old battery.
Three causes of explosions:
Ⅰ. Battery case explosion caused by high internal pressure of the battery
By the working principle of lead-acid battery, people know that during the charging process of the battery, especially at the end of charging due to overcharging, water decomposition into hydrogen and oxygen, short circuit, serious sulfide and the temperature of electrolyte rises sharply when charging, all will make a lot of water evaporate. At this time, if the vent hole of the liquid filling hole cover is blocked, because there is too much gas to overflow, the internal technical structure of the battery before the implementation of the new battery standard is simple, the pressure will rise very high, causing the battery slot deformation first, when the internal pressure reaches a certain pressure will burst from the battery slot cover combination or other weak places, which is a physical process.
When the internal pressure of the battery is higher than 0.25MPa battery burst, the burst location is located in the hot air combination of the slot cover or stress concentration at the corners.
Ⅱ. Battery explosion formed by hydrogen gas in open flame
The explosion limit of H2 and O2 gas mixture is 4%-96% of the mixed gas volume of H2, and the explosion limit of H2 and air mixture is 4%-74% of the mixed gas volume of H2. If 80% of the overcharge is used for electrolytic water, the H2 content inside the battery is greater than the explosive range, when the accumulation of hydrogen in the battery or air to the explosive limit, when encountering open flame will form an explosion, which is a chemical reaction.
The study found that the battery explosion belongs to the branched chain explosion reaction. Such explosions occur too often in the case of overcharging, if the battery internal pole, through the wall welding and other places there are false welding points, the battery has a higher chance of explosion. A qualified battery in normal use conditions will not occur under the self-generated heat explosion reaction. When the battery charging voltage is higher than 14.4V for gasoline cars and 28.8V for diesel cars, an explosion may occur under the conditions of the simultaneous presence of fire. Through the vehicle inspection of the battery explosion, it was found that most of the voltage regulator is defective and the battery is in a serious overcharge state.
Ⅲ. Exhaust Hole Blockage
Due to the traditional lead-acid battery exhaust hole blockage, the battery first burst, burst caused by battery vibration, poorly wired poles generate sparks, thus forming an explosion.