Explore the quality password of Xiaomi’s ultimate innovation system for charging technology

"Fast and stable" to solve the battery anxiety of mobile phone users

– Exploring the quality code of Xiaomi’s ultimate innovation system for charging technology

Our reporter, Yue Qian

How to charge quickly is a must-have option in modern life, not only to be able to charge, but also as fast as possible. Xiaomi’s super fast charging technology has brought unexpected surprises to consumers: it only takes 8 minutes to fill a 4000mAh battery, enough to use normally for a whole day.

Xiaomi’s innovation has relieved people of the need to worry about running out of battery power on their mobile phones.

Imagine what you can do in the 8 minutes after getting up in the morning? Have a cup of coffee to refresh yourself? Simply stretch? Or take a shower? For Xiaomi’s phone, these 8 minutes are enough to power it up for the new day.

From the world’s first 120W wired fast charging technology to the world’s first 200W charging technology, Xiaomi has brought mobile phone charging into the "8-minute era", truly achieving a "qualitative change" in the charging experience, and allowing more and more users to completely bid farewell to power anxiety.

Behind this technological change is the ultimate innovation system of mobile phone charging technology launched by Xiaomi since September 2018. In just over two years, Xiaomi has completed the change from "chaser" to "transcendent" to "leader" in the field of mobile phone charging with the spirit of self-evolution, and once again verified the strong driving force of Xiaomi’s "user-centered" quality improvement concept.

The reporter conducted in-depth interviews with the ultimate innovation system of mobile phone charging technology to explore the quality code of Xiaomi’s charging technology evolution iteration.

Quality password one:

Driving technological innovation with user feedback

What is the driving force of technological innovation and quality improvement? At Xiaomi, this answer has long been deeply rooted in the hearts of the people – user-centered, with the ultimate goal of pursuing the ultimate user experience. For the research and development of charging technology, it is not only to make mobile phone charging faster and more stable, but also to make the charging experience better and cooler.

In the process of technological improvement, Xiaomi innovatively built the UIOCT system of charging technology. The system is based on improving the user’s charging experience, taking user feedback and pain points as the starting point and driving force for continuous technological innovation, and ending with the landing of new products requested by users. "For charging technology research and development, the user is the starting point and the end point" – this is the consensus of the charging technology team.

In order to truly understand the needs of users, the charging technology team collects user feedback and suggestions through various channels such as Xiaomi community, service system, customer service phone, etc., analyzes user pain points and makes improvements one by one. Many problems do not have ready-made solutions to learn from, and the team can only explore in the "no man’s land", through continuous trial and error to find the most satisfactory solution for users.

Can charging be faster? This is the common expectation of mobile phone users. Under the condition of existing lithium batteries, Xiaomi has created a multi-level progressive current regulation technology in the industry, which can refine the charging current step by step, effectively increasing the charging speed by more than 10%.

When charging, it generates heat, which is caused by the characteristics of the lithium battery of the mobile phone, and it is also a problem in the industry. Is it a detour or a face-to-face difficulty? Xiaomi’s engineers chose the latter and innovatively developed a dual-mode switching control technology, allowing users to adaptively switch the charging mode according to the usage scenario, effectively dispersing hotspots and bringing a better temperature rise experience.

Nowadays, in order to improve the battery power of mobile phones, mainstream manufacturers almost all adopt the "dual-cell" solution, but with it, the battery loss increases and the battery life is reduced. This is also the reason why users complain that "charging fast and falling fast". In this regard, Xiaomi once again broke out of the new track and innovatively developed the single-cell charging chip Surging P1, which makes the battery cell density higher and the battery life longer, achieving "both fish and bear’s paw".

In order to make charging more convenient, Xiaomi customized a fast charging cable. Considering that users may use other brands of charging plugs, engineers have carried out a large number of self-developed designs while also taking into account the charging compatibility of the cable. For all mainstream brands of chargers and mobile phones on the market, they have done technical tests. "This job is completely to make it more convenient for users to use." In order to solve the problem of incompatible charging plugs of a certain brand, engineers worked overtime until late at night for several days, and finally solved the problem, so as to ensure that users can enjoy a fast and stable charging experience no matter which charging plug they use.

It is worth mentioning that while solving users’ charging pain points, Xiaomi has also created a charging experience that exceeds expectations for users through technological innovation, and even changed consumers’ charging habits. Taking 200W second charging technology as an example, you can fully charge your phone in the morning, and you no longer have to worry about forgetting to charge. "Once you have this experience, you (users) can’t go back," the team leader said proudly.

Quality password two:

Establishment of an Interdisciplinary Expert Review Committee (TMG)

For a long time, the field of mobile phone charging technology has faced the "28 dilemma", that is, high-current charging time only accounts for 20% of the total charging time, but can charge 80% of the power; constant-voltage charging time accounts for 80% of the total charging time, and can only charge 20% of the power.

In order to solve the "28 dilemma", it involves charging solutions, charging chips, charging equipment and other departments and fields, each with its own technical difficulties and bottlenecks. In the face of new technical solutions, different departments will have different views. On the one hand is the solution to the problem that has been hard to come up with, and on the other hand is the latent risk that may arise. Should we continue or give up?

At the "crossroads" of technology, the cross-disciplinary expert review committee (TMG) built on Xiaomi’s organizational structure plays a key role.

Engineer Jiang Helin introduced that in order to break through the "28 dilemma", the Xiaomi charging technology team finally discussed and came up with the MI-FC solution idea of "increasing the voltage value of the battery and prolonging the charging time of high current" through dozens of brainstorms. However, increasing the voltage will cause risks such as excessive oxidation, resulting in shorter battery life.

Experts in different fields in TMG jointly review the technical solution from objectives, risks to feasibility, leadership and other dimensions. In the technical pre-research stage, TMG can accurately and quickly determine the solution; in terms of solving technical differences, TMG can upgrade the device pre-research to the whole machine charging pre-research, realizing from a single partial design to overall performance debugging, thereby improving the user experience.

Specific to the MI-FC technical solution, TMG experts anticipate that the solution is feasible and recommend that aging tests be carried out as soon as possible to verify whether there is a risk of excessive oxidation. After a series of work such as proofing and testing, the team spent more than 5 months to finally formulate a feasible plan. Due to sufficient pre-research, the plan was successfully transplanted to the device-level project, which greatly reduced the time required to develop the device and fully guaranteed the research and development efficiency.

Not only the MI-FC technical solution, but also the more than 800 patents applied by the project team are inseparable from the technical assistance of TMG. TMG comprehensively considers and evaluates various technical solutions to ensure the accuracy of the research and development direction and escort the overall innovation of mobile phone charging technology.

Quality password three:

The research and development of excellence

In the process of reaching the peak of technology, the Xiaomi charging technology team also encountered many difficulties, but every time they relied on uncompromising research and development determination to successfully break through.

Li Min, an engineer at the baseband technology department of the hardware R & D department, said that in order to achieve 120W second charging, Xiaomi specially developed a custom charging chip. But less than four months before mass production, the chip temperature was too high. "There was too much pressure at that time, but we had to find out the reason." Li Min said that Xiaomi has never been vague about the quality requirements of the product.

The team and suppliers sorted out all possible reasons from hardware to software, and the technicians directly entered the factory to conduct nearly a month of non-stop testing, troubleshooting problems one by one, and conducting 500 to 700 stress tests on each batch of new samples (under normal circumstances, only one stress testing is required). Finally, the yield of customized chips was reduced from the highest 1000ppm to less than 50ppm, fundamentally solving the quality risk of chips, and bringing the most advanced charging experience to the long-awaited users as scheduled.

In the eyes of the engineers of Xiaomi’s charging technology team, records are meant to be broken. After achieving the 120W second charging technology, Xiaomi continued to explore the "no man’s land" in the field of second charging technology and began the research and development of the 200W second charging technology.

In order to avoid the short circuit problem that may be caused by high-power charging, the team needs to minimize the thickness of the battery pole pieces and minimize the transmission path, which brings great challenges to the processing process of the battery pole pieces. To this end, the engineers started from various aspects such as equipment improvement and process improvement. After many tuning on more than 6,000 batteries, they solved many problems such as pole piece fracture and curling. Finally, they successfully developed a 10C pole piece with a thickness of only half of the traditional pole piece, which is about the thickness of a piece of A4 paper. "At present, only Xiaomi can do it in the industry." Jiang Helin said proudly.

Those who win are powerful, and those who win are strong. In the eyes of reporters, Xiaomi’s charging technology is already leading the industry. But Xiaomi is putting pressure on itself to compete with itself in the "no man’s land" and constantly surpass itself, which is very commendable. For industrial development, this "leader" is leading the industrial chain, supply chain and quality chain to achieve a comprehensive leap, promoting the high-quality development of the smartphone industry, and accumulating more positive energy for China’s manufacturing "quality revolution".

"China Quality News"