Last time, Brother Neck already discussed with everyone about the incident where the M7 rear-ended and caught fire.
In the comments section of the article, besides AEB, everyone is also very concerned about the issue of the hidden door handle not popping out. Because from the videos of the collision, it can be seen that during this collision, the hidden door handle of the M7 did not pop out.
Many netizens suspect that it is for this reason that whether it is a kind passerby who comes to help or rescue personnel who arrive later, they cannot open the car door and can only resort to breaking the window, wasting precious rescue time.
According to our simple understanding, after a vehicle collision, the doors should generally unlock automatically, and at the same time, the door handle should pop out.
But the reason why the door handle didn't pop out is really unclear.
Some bloggers have indicated that during the collision, the speed reached up to 115 kilometers per hour. The water truck intruded into the cockpit in less than a second, cutting off the power lines, causing the vehicle system to fail to flash, resulting in the failure of functions such as the door handle popping out.
In addition, it cannot be ruled out that the door handle was stuck by the door, or the small battery was smashed, leading to the failure of the emergency mechanism, and so on. In any case, it is currently impossible to make a definitive judgment on the specific issues in this accident.
We still need to wait for the authoritative announcement from the police to know exactly what happened.
However, in any case, the retractable door handle will have to take the blame.
Many internet users say that if traditional mechanical door handles were used, there wouldn't be so many issues.
This statement actually makes sense.
Because traditional mechanical door handles are designed to be exposed, with at least a handle to pull, the door opening mechanism is fully mechanical and does not require electricity.
However, hidden door handles are different. You have to make it pop out for users to open the door, right?
When it comes to this "pop-out" mechanism, different car manufacturers have different design approaches. Broadly speaking, they are usually divided into rotary and flat push types.
In the early days, some electric cars mostly used rotary handles, such as the XPeng P7. After unlocking the door, the door handle will automatically rotate and pop out.
But we have to say that this method is not safe, then we are really blaming it wrongly.
Because rotary door handles will not encounter the problem of getting stuck and unable to open the door. Besides electric control, they generally retain a manual pressing method. Even if it doesn't pop out by itself, if you press down from the other side, it will still come out.
This feature, Tesla Model 3 owners have the most to say about. After all, they simply won't pop out by themselves, but rather, like a lever, you need to press on one side to lift the other side. It can be said that it is a mechanical door handle.
The other type of flat-push door handle is more likely to cause the situation where the car door cannot be opened.
Because it lacks any other physical popping-out mechanism, if the car does not rely on the motor to push the door handle out, you simply cannot open it from the outside.
You might think about forcefully prying it open, which is not impossible, but when it comes to a life-threatening moment, by the time you manage to pry it open, it might already be too late.
And generally speaking, the push-to-open door handle structure is more complex and takes up more space. So, in practical use, it is indeed more prone to breaking.
An example of this is the typical push-to-open door handle structure shown in the image below. It is based on a traditional door handle but includes a handle to operate the opening motor, as well as two capacitive position signal switches.
Because the door handle is fully embedded inside the car door, it takes up more space in the door arrangement, and some collisions and squeezes may cause the pop-out channel to be blocked.
Moreover, the flush door handle must retain the pop-out mechanism, which requires an additional motor and corresponding wiring. Apart from possible poor contact, electronic system failures, etc., there have been cases of gear lubricant leaks causing the door handle motor to explode.
Although car manufacturers have optimized materials and processes, such as precision control of sheet metal parts and the development of special nut adjusters, the flush door handle remains a safety hazard.
And now, there are no relevant national standards for such door handles, so it's hard to say how far automakers can go in terms of safety redundancy in this matter.
Some automakers may automatically roll down the windows within 15 seconds after a collision, but this still relies on a 12V small battery. There are also some automakers that have a separate backup battery inside the door to specifically control the door opening.
But to achieve the sleek look of hidden door handles, they have applied countless patches. In my opinion, it might be better to just...
However, before considering how to open the door, there is actually a prerequisite.
We first need to ask, is the car door unlocked?
Otherwise, even if you are a mechanical door handle, or you have pulled out the hidden door handle, you still can't open the door.
For example, in the case of the accident, did the M7 automatically unlock the car door?
The customer service response was that most vehicles currently do not have automatic unlocking function. In the event of an accident, even if you pull out the door handle, you still won't be able to open it.
The only way to open the door is from the inside, but at this point, the passengers have all lost consciousness, so everyone can only break the car windows.
However, the customer service's explanation is not valid.
According to the national standard GB20071 "Protection of occupants in side collisions of automobiles," it clearly states that after a collision, the doors should close but not lock. In other words, they must automatically unlock.
In the 2021 version of C-NCAP (China New Car Assessment Program), a requirement has been added that the front doors must be unlocked automatically after a frontal collision. Failure to have this feature will result in a deduction of 1 point in the crash test score.
At the beginning of this year, the Ministry of Industry and Information Technology's "Passenger Car Rear Collision Safety Requirements" (Draft for Solicitation of Comments) also mentioned that "after the collision test, the car door should be in the unlocked state," indicating that this is a widely recognized industry standard.
As a car, you have to comply with the national standards, right?
Later, netizens dug out the owner's manual of the M7, which clearly stated that it does have an automatic unlocking feature.
However, even with automatic unlocking, it does not mean that the vehicle doors can unlock 100% after a collision.
Fundamentally, automatic unlocking is a basic feature that mainly involves two modules: the Airbag Control Unit (ACU) and the Body Control Module (BCM).
From the names alone, you can tell that the ACU is linked to airbags, while the BCM is responsible for controlling various functions of the vehicle.
The principle is this: when the car's collision sensor detects a crash, the ACU opens the airbags and sends an electrical signal to the BCM, which then controls the unlocking of the car doors.
To put it simply, the ACU is like the BCM's assistant. It gathers feedback from various departments, addresses some issues on its own, and then reports to the leader, the BCM, to handle less urgent matters like unlocking the car doors.
If during a collision, the wiring harness connecting the ACU, BCM, or even the intermediate transmission is damaged, there is a chance that the door of the vehicle cannot be unlocked.
Moreover, both this system and the concealed door handle require electricity. After a collision, the power battery will be directly cut off, and all functions inside the car rely on the 12V small battery to stay operational.
If at this moment, the small battery is also damaged, the doors will not be able to unlock automatically.
For example, in July 2022, there was a similar incident where a Lexus LM caught fire after a collision, and the doors could not be opened, resulting in 1 fatality and 2 injuries. Even though this car had traditional door handles, rescuers still had to break the windows to save the occupants.
So it's not conclusive that the reason the car door won't open is all because of the hidden door handle.
But no matter what, if you have a traditional mechanical door handle, as long as the vehicle is unlocked and the door isn't jammed, it's still easier to pull open.
This is actually the biggest flaw of hidden door handles. Even if the vehicle is unlocked, if the hidden door handle doesn't pop out, people outside still have no leverage to open the door.
So even if the vehicle is locked, it can still delay rescue efforts from outsiders, especially untrained good Samaritans. When they see the handle not popping out and the window not rolling down, opening the door becomes a real challenge.
Therefore, the core issue is still solving the process of unlocking the door after a collision. Either make the hidden door handle optional, because I really don't like this thing.
