In recent days, a large number of complaints about WM Motors have suddenly emerged on major websites. The content is also much the same, saying that around New Year's Day, WM secretly gave users a battery system "upgrade" in the name of serving car owners, inspecting vehicles, and giving away 200 yuan Jingdong card.
Then the "magical" thing happened, the so-called upgraded vehicle, the endurance has dropped significantly. Everyone generally feedback that before the upgrade, it can still run about 350km, and after the upgrade, 300km cannot be run, and even the endurance has dropped by nearly 100km.
There is also a car owner is a singer, specially for this matter to create a song, called "200 pieces will deceive me", very detailed about the ins and outs of the matter, everyone is interested can go to search.
However, I believe that everyone is more concerned about what WM has done to the user's vehicle? What is its motivation for doing so? Rong Kung Fu Car to give you a dissection.
(1) The secret of "locking the electricity" to prevent the battery from being "overcharged"?
In fact, the so-called "upgrade" of WM is to do a very simple thing, that is, to "lock the electricity". What is the "locked power", such as the total capacity of the battery is 100%, through the control of the BMS battery management system, only let it charge to 95%, and then charge can not be charged.
Kung Fu Car looked at the descriptions of netizens, the original battery full voltage should be 407.5V before the upgrade, and after the upgrade, the general voltage was only about 396.5V. WM's rights defense group simply issued an announcement that as long as everyone charges to 97% of the voltage is less than 400V, charged to 99% of the voltage is less than 406V, it is locked. Because even if the consistency of the power battery is deviated, it will never deviate from 407.5V to less than 400V.
Why is this voltage data so important? If you look at the capacity unit of the power battery, it is "kWh", which is actually the power multiplied by time. Under the same output conditions, the discharge current and discharge time of the battery are basically unchanged. In other words, the voltage drops, and the capacity of the battery decreases synchronously.
The reason why Weima did this also came out, that is, not to let users "full".
Because the "full" continues to charge, the harm to the power battery is actually quite large, and the damage of many batteries is because the battery continues to be replenished after the battery is fully charged, which triggers the chain vector reaction inside the battery.
For example, the simplest example, many hybrid models for the battery settings, are "shallow charge and shallow release". For example, Nissan's recently listed Xuanyi e-POWER, its battery power is always fluctuating between 40%-80%, Honda's i-MMD is more "excessive", will always maintain more than 55% of the power, they greatly extend the battery life in this way.
But pure electric models do not have this condition, because they are more dependent on batteries. Of course, in theory, 600km endurance, but fixed only let it reach 550km, can effectively avoid this problem, but at this stage there will undoubtedly be no manufacturers to do this, they are 550km to promote the practice of 600km, in order to protect the battery reverse, that is not their own with their own can not go?
Therefore, WM also hopes to adjust the charging problem of the battery through the BMS battery management system, so that it is not full as much as possible, and there will be no "overcharge", so that the battery can be indirectly protected. But now the situation is that Weima is a bit overwhelmed.
(2) Burn three cars in four days, what is the solution to the battery problem of WM?
In the last few days of the end of last year, WM made a big news, that is, in the four days from December 20 to December 23, 2021, it had three spontaneous combustion accidents. And this is not the first time that WM has experienced spontaneous combustion intensively, in October 2020, WM also had several consecutive spontaneous combustion accidents.
Although it is not too rare to say that the spontaneous combustion of electric vehicles is not too rare today, as a new force with annual sales of only 40,000 vehicles, WM's "facelessness rate" in this regard is too high. After all, Wei Xiaoli's sales are more than double that of it, and BYD's sales of new energy vehicles are nearly 20 times that of it, and there are not so many problems. Even now when many people mention Weima, the first reaction is spontaneous combustion.
Because of this, as a new force in the old car manufacturing, and even the runner-up in the sales of the new force in 2019, WM has not been able to go public so far, and even the sales volume in 2021 has ranked sixth among the new forces.
Weima is not without a solution, but the answer is no solution. As early as 2020, when WM continued to spontaneously combust, the entire company reviewed its battery supply chain.
Because WM itself does not produce batteries, its batteries are actually from suppliers. But WM has another problem, it is one of the few models in the new forces that is neither deeply bound to battery manufacturers nor takes the high-end route. Weilai, Xiaopeng, and Ideal are highly positioned, and they can invest more costs in battery procurement, coupled with high sales, and the right to speak is naturally more sufficient.
Although WM has four suppliers of ZTE High Energy, Tafil, Ruipu Energy and Ningde Era, the strength of these battery manufacturers is different. For example, the battery in the Ningde era has been in short supply, and even requires many manufacturers to sign an "exclusive agreement", and how much power can it give to Weima?
So the result is that Weima's problems are frequent, but no manufacturer comes out to "take responsibility", this confused account is still continuing to this day, and continues to eat away at Weima's reputation.
Recently, manufacturers have made the next policy of "locking electricity", which is probably the same reason. If you can't get the supplier, you try to get the user. But from the result, it should be that stealing chicken is not a corrosion of rice.
(3) To solve the problem of spontaneous combustion, the practice of friendly businessmen is worth learning
The safety of the battery is indeed a big problem, and it is difficult to avoid it at this stage. WM wants to solve this problem, just rely on "restraining" users is certainly not enough, you may wish to consider learning from the practice of friends.
As the industry leader, in fact, Tesla, like WM, does not produce batteries. Tesla first became famous, and many people said that its "core technology" was 7,000 batteries. It is these densely packed 18650 rechargeable batteries the size of the No. 5 battery that make up Tesla's battery pack.
But although Tesla does not produce batteries, its management of batteries is a must. It monitors a single cell to ensure that it is not overcharged or over-discharged, always keeping the SOC within a reasonable range. In addition, it cools each part of the battery through its own temperature control system, so that the battery temperature is maintained within the appropriate operating temperature range, thereby achieving longer battery life.
Don't study the battery, study the control, this is definitely a train of thought. Of course, the technical content is not small.
Another example is GAC Aean, which also does not produce batteries. However, it will develop its own battery cell formulation to ensure that the safety of the battery cell itself is good enough. Secondly, it took the right to pack the battery in its own hands and launched its own set of independent "magazine battery" technology. The key to this set of technologies is to "thinen" the package of the battery cell, each "thin grid" is as strong as a magazine, even if there is a problem inside a magazine, it will not cause the entire battery pack to thermally run out of control.
Although this may seem "troublesome", it is certainly not as simple as buying it directly from a supplier. But it can ensure that there is no problem, and naturally it can also be used as a long-term solution.
Then there is the ability to "learn" BYD, its blade battery adopts a module-free design, with lithium iron phosphate batteries, to achieve an energy density similar to a ternary lithium battery, and has the high safety of lithium iron phosphate batteries, its spontaneous combustion possibility is smaller.
Of course, this is not for WM to develop batteries like BYD. BYD has been doing this for more than 20 years, and Weima can't do it. But it can directly purchase BYD's batteries, and Fordy batteries have opened up export sales.
(4) Kung Fu shooting
In general, Weima made a farce of "locking electricity", which is really because of "burning". A few big news stories a year, almost let the listing be postponed indefinitely. I believe that Weima itself is also helpless. But it is not okay to face it, after all, the battery is too important for electric vehicles, and these small actions are only the collapse of word of mouth.
I hope that WM can be down-to-earth and solve the safety problem of the battery as soon as possible, after all, there are still many users and investors who are optimistic about it.