While electric vehicles may be structurally more waterproof, are they truly fearless when facing flooded roads in real-world driving?
Why are gasoline-powered cars susceptible to water damage?
First, let's look at why gasoline-powered cars are afraid of water.
The core of a gasoline-powered car's power is its engine. The engine's working process consists of four steps: intake stroke, compression stroke, power stroke, and exhaust stroke. This entire cycle is called the Otto cycle.
Simply put, the car moves by the interaction of the mixture of fuel and air, which drives the pistons in the engine.
Because engines need to draw in a lot of air to function, if water gets into the air intake of a gasoline-powered car, the engine will immediately shut down. If you stubbornly try to restart it under these circumstances, water is very likely to be drawn into the engine, and permanent damage will be inevitable.
This is precisely why we should try to avoid buying "flood-damaged cars" in the used car market.
However, shallow water generally does not pose a significant threat to gasoline-powered vehicles. Generally, the safe wading depth for a regular sedan is 30 to 40 centimeters, while for an SUV it is 70 to 80 centimeters. Of course, we cannot precisely measure the wading depth while driving, so we usually observe the water level in the rearview mirror. If the water level is above the lower edge of the wheel rims, we should be cautious.
Of course, when facing extreme weather such as torrential rain or typhoons in Zhengzhou, the best course of action is to stay home. If you are already trapped in your car, it is best to abandon the vehicle and escape, since the car is beyond repair and life is the most important thing.
02 Electric vehicles may not be so afraid of water, but they still cannot wade through water at will.
If gasoline-powered cars are so vulnerable to water, would electric vehicles perform better when faced with standing water?
Theoretically, the answer is yes. The power module of a pure electric vehicle mainly consists of three parts: battery, motor, and electronic control system, which are commonly referred to as the three-electric system.
Some might think that since electric vehicles don't require air input to operate, as long as the three-electric system (battery, motor, and electronic control system) is properly waterproofed, they can withstand the test of deep water, right?
In fact, electric vehicle battery systems do have good waterproof capabilities. According to relevant national requirements, the recommended dustproof and waterproof rating for electric vehicle battery systems is no less than IP67. This means that the battery system must be able to withstand immersion in one meter of water for at least 30 minutes without any water entering the battery casing to be considered合格 (qualified).
However, this does not mean that we can drive electric vehicles into floodwaters at will, and the reason lies precisely in their power system.
Even though electric vehicle battery systems need to meet certain dustproof and waterproof requirements, spontaneous combustion of cars after being submerged in water still occurs from time to time, as evidenced by experimental results from multiple research teams.
According to existing research, if the battery module's casing has minor damage that goes undetected, the battery will release a large number of sparks once it comes into contact with water, and may even spontaneously combust even when submerged in water.
Indeed, electric vehicle manufacturers can further improve its waterproof capabilities from the perspectives of waterproof casing and circuit design. However, firstly, rainwater is somewhat corrosive and will mix in a large number of impurities, so we cannot guarantee that the battery module will be safe when exposed to rainwater. Secondly, this will further increase the overall cost and weight of the vehicle and shorten its range.
More importantly, insurance companies generally won't cover total damage caused by attempting to drive through water. Given these combined factors, even relatively water-resistant electric vehicles are best avoided when faced with deep floodwaters.
Of course, some people might ask: since electric vehicles are also susceptible to water damage, can they still be charged in the rain? Actually, as long as there's no water on the charging port, charging shouldn't be a problem. However, if it's raining heavily, it's best to choose an indoor charging station, just in case, for safety reasons.
