This is an unprecedented recall incident among the new forces. Last week, Lideal suddenly launched a voluntary recall of MEGA 2024 vehicles starting this week.A total of 11,411 vehicles.The official reason for the recall is that this batch ofInsufficient anti-corrosion properties of coolant, under certain conditions, the cooling aluminum plates of the power battery and the front motor controller in the cooling circuit may corrode and leak, causing the vehicle to have a fault light, limited power, and failure to power on. In extreme cases, it may cause thermal runaway of the power battery.
The recall measure is to replace the coolant, power battery and front motor controller of the vehicle free of charge. Ideally, it would take one working day to replace a single vehicle. The total cost of replacing the 10,000-car vehicle and the entire battery pack must be hundreds of millions.
This recall is related to a MEGA spontaneous combustion accident in Shanghai not long ago. However, the investigation of the accident has not yet been completed, so Ideal stood up and admitted that he had made a mistake.
Let's just say, this attitude of standing at attention and being beaten is really rare.
So here comes the question, why does Ideal have to pay such a big price, even to replace the battery, just because of a coolant issue? Brother Neck talked to several industry insiders related to vehicle thermal management and found outCoolant doesn’t look like much,But for new energy vehicles, it can be regarded as a crucial thing.
We all know that coolant is an essential item whether it is a petrol car or an electric car. Its function, as the name suggests, is to quickly dissipate a large amount of heat generated by parts, and it also has anti-freeze, anti-corrosion and other functions.
Experienced drivers who drive petrol vehicles should be familiar with this. Brother Neck has encountered it before. Someone stepped on the accelerator too hard and caused the engine to smoke. Then they poured some water into the coolant and continued running. (Of course, Brother Neck does not recommend this)
This is because water is indeed one of the components of coolant.Generally, there are two main components of coolant, ethylene glycol (sometimes propylene glycol) and water. The proportion of water is about 40-60%.The amount of water determines the freezing point and boiling point of the coolant.
On oil trucks, the coolant is actually not that particular, otherwise water would not be added instead.
After all, the engine of an oil truck is a big heat source, and the coolant mainly circulates around the engine block. This is a relatively independent mechanical system that does not involve high-voltage electricity. The coolant can just keep an eye on this big guy. You can drink some water occasionally, you can handle it for a while.
But on trams, batteries, motors, electronic controls, including smart driving domain controllers, etc. are all heat sources. These are all high-voltage electrical components. Different parts have different working temperatures. Car companies will connect these parts that need heat dissipation with cooling water lines to form a circulation system.
The working environment is different, and obviously the requirements will be different. The biggest difference between electric car oil car coolants is conductivity, which is the ability of the liquid to conduct electricity.
Oil trucks mainly focus on a heat dissipation indicator and don't care about whether it conducts electricity or not. Anyway, the small 12V battery can't hurt you. Therefore, the conductivity of oil truck coolant is very high, about 2000-5000 μS/cm.
However, a bunch of parts inside and outside the tram have high voltages of 400V and 800V. Once a collision causes the coolant to leak, electric shock can be a serious accident. Therefore, the conductivity of the tram coolant must be very low.Less than 100μS/cm, only a few tenths of that of an oil truck.
In addition to conductivity, because there are more cast iron materials in the engine of the oil car, and more aluminum materials in the cooling system of the electric car, the formulas of the two are also different.
Perhaps because this thing is relatively new, it was not until October this year that the first version of the national standard for tram coolant was issued. Prior to this, the coolant of electric cars had been based on the standard of 13-year-old oil cars.
But we don’t need to panic. Neck Brother consulted relevant people from the car companies, and he said: "The original standards were too low, and car companies would not comply with them. Although the new national standard has become higher, basically the standards of enterprises will be higher than the national standard."
Based on this distinction, the coolant of electric cars is obviously more complicated than that of oil cars. Therefore, unlike the relatively common coolants in the oil car era, new energy car companies will design their own coolants according to the characteristics of their own models.
Although they have different approaches, generally speaking, after a car company chooses a coolant, it will not make any changes. At least models of the same platform will use the same coolant.
First, because the coolant development cycle is not short, car companies cannot use a new coolant for every new model.
Secondly, there are too many parts involved in the coolant in the car. From the battery system to the material selection of the front and rear motors, whether the coolant matches must be considered.
How big of an impact can this have? Some car company R&D personnel directly stated that "first determine the coolant, then develop parts." They first determine which coolant to use, and then all parts are developed and matched according to this coolant.
"Because once the coolant is changed later, all the tests on other parts will have to be redone, so this is basically not done. For example, if there is a leak in the test of the cooling water pipe, then the formula of the water pipe rubber will be changed, not the coolant."
It can be said that the coolant affects the entire car...
The test here also includes the anti-corrosion problem that MEGA has this time. Note that this anti-corrosion issue is not to prevent the coolant from rotting, but to prevent the coolant from corroding other parts.
In order to avoid this situation, there will be a certain amount of corrosion inhibitors in the coolant to slow down and inhibit corrosion.
The formula of the corrosion inhibitor is a secret of each company, so how do you know whether the corrosion inhibitor is useful? In the national standard, there are two coolant corrosion tests: static corrosion and cyclic bench corrosion.
Static corrosion is to soak the material in coolant and let it sit for 14 days to see if it will corrode. The circulation bench is to put the radiator, water pump, power battery cold plate and other parts together to simulate actual working conditions, do it for 40 days, and then see the effect.
But experiments are experiments, and the actual situation is still much more complicated.
For example, the national standards only use specific materials for corrosion such as copper, brass, and 3003 aluminum. However, the cooling system engineer Xiao A told me that the actual materials in contact with the coolant in the car are far more than these. When they were developing, they needed to conduct corrosion tests on all materials in the car that come into contact with the coolant.
For another example, the national standard requires that the experiment be carried out in a high temperature environment of 80°C. Xiao A said that they will do it under even worse working conditions.Autoclave corrosion test, adding high pressure to high temperature, using even more torture methods.
But after all, these tests are compressed time and intensive working conditions. One or two months of testing are used to simulate the results of long-term use of the vehicle. Just because the test has passed does not mean that problems will not occur later.
In addition to corrosiveness, the coolant also has rubber material compatibility, stability, etc., which are all long-term tests. It can also be seen from this that developing a suitable coolant requires considering many dimensions and is not an easy task.
Back to this ideal recall. As the first pure electric model on the market to use 5C batteries, MEGA has a huge demand for heat dissipation. Some people in the industry believe that it may be because of this that it does not use the L series coolant.
At a time when all car companies are compressing the development cycle and competing for the speed of new car launches, MEGA's coolant problem may also be related to the new technology and the limited development cycle.
MEGA comes standard with dual front and rear motors, both of which are in contact with coolant, but the ideal recall would only involve replacing the front electronic control, not the motors. Little A guessed that this may be because the aluminum alloy material of the motor is different, but why this is the case may be very complicated.
“Running more road tests, covering hundreds of thousands or hundreds of thousands of kilometers, is the most suitable way to verify the problem.."
Ideal's way of handling the problem this time was really quick. But judging from the problem itself, new energy vehicles, a large electrified device, are really too careless.
An inconspicuous part may cause a huge spontaneous combustion accident. Perhaps all of us should be more patient and careful when dealing with this new thing.