Beware of "charging while charging" Research by the mobile market and the University of Electro-Communications to prevent smartphone battery deterioration
On March 30, the mobile market announced the results of research on the "Smartphone Battery Deterioration Research Project". This research is an industry-academia collaboration project with the University of Electro-Communications i-powered energy system research center Yokokawa training room, and Professor Shinji Yokokawa of the same lab also took the podium at the press conference.
[Correction: 10:20 on April 6, 2021 There was an error in the name of the research center when it first appeared. I apologize and correct it. ]
Purchase prices drop due to battery deterioration
The president of the mobile market, Hamaichi Awazu, said that during the recent corona crisis, he has no time to telework at a cafe or watch videos at home. It is pointed out that there are more opportunities to put a load on the battery, such as longer. Conditions such as a swollen battery in a device can significantly reduce the value of a trade-in, he said.
Mr. Hamaichi Awazu, CEO of the mobile marketMr. Awazu estimates that the loss in value of terminals due to such events is estimated to be as high as 422 billion yen in the market as a whole, and is ignored. He warned that the economic loss was unavoidable. In addition, degraded batteries may cause accidents such as fire or explosion, so it is also important from the perspective of disaster prevention.
As an issue in conducting actual research, smartphones are highly dependent on the individual. It is said that the capacity, shape, and usage environment are diverse. In addition, many of the recent models have a built-in LiB (lithium-ion battery), and it was necessary to have a method to indirectly grasp the deterioration state. For these reasons, the first survey adopted the approach of conducting a 46-item questionnaire and analyzing it using statistical methods.
"Charging while charging" is a factor in battery deterioration
Mr. Minoru Asano of the Yokogawa Laboratory explained the details of the research. Based on questionnaire data from 1,800 people, he analyzed usage methods and user attributes that lead to battery deterioration. Multiple statistical methods were used for the analysis, including generalized regression analysis, Kmeans method, stratified clustering, and structural equation modeling.
Mr. Minoru Asano of Yokokawa Laboratory, The University of Electro-CommunicationsAs a result, while the amount of deterioration tends to increase as the number of days of smartphone use increases, the degree of deterioration varies depending on how the smartphone is used for the same number of days. tended to be large. In addition, it was found that items related to software settings, usage, time, and charging are the factors that affect it. As for how to mitigate deterioration, he mentioned whether the application is up to date, whether the energy saving application is used, and whether unnecessary accounts are deleted.
Analysis results by the Kmeans methodExamples of "how to suppress battery deterioration" and "how to accelerate deterioration" found from analysis by structural equation modelingIn particular, When charging while playing a game, the internal temperature of the terminal rises. Specifically, while charging alone increased by 1.2 degrees, playing games while charging increased by 8.9 degrees. Excessive use of the battery at elevated temperatures can accelerate deterioration. Regarding user attributes, the younger the age group, the more users watched videos and played games while charging.
[Correction: 22:20 on April 5, 2021 At the time of first appearance, it was said that ``the increase was 1.2 degrees when playing without charging,'' but the correct answer is ``the increase was 1.2 degrees when charging alone.'' is. I apologize and correct it. ]
According to Professor Shinji Yokogawa of the University of Electro-Communications, according to Professor Shinji Yokogawa of the University of Electro-Communications, it is said that charging tends to raise the temperature of the battery and cause deterioration. , The fields that utilize battery-powered products are expanding, and in addition to the mobile and wearable fields, batteries are also used in factory transport robots such as AGVs. It is said that there are more batteries than I thought in my life, such as. In the future, he said, the importance of battery management will increase in order to realize a system that supplies electricity in an independent and decentralized structure as a society.According to Professor Yokokawa, if the internal temperature of the battery rises by 10 degrees, the amount of deterioration will approximately doubleDevelopment of a battery deterioration diagnosis system
< p> The mobile market is developing a system that diagnoses the degree of deterioration of the battery from an application that is pre-installed on the terminals sold and rented by the company. By putting a load on the battery for 6 minutes, it is possible to numerically analyze the degree of deterioration. As the second survey, from July 2021, we plan to collect 100 monitors for each iPhone and Android and conduct an analysis using the same app. In addition, we will proceed with an approach that uses a USB PD measuring device and analyzes the changes in current and voltage at the start of charging through the entire circuit.Regarding future research using the app"We would like to combine the results of the questionnaire, the app, and the results of the PD measuring device to predict deterioration. By enabling users to determine when to sell their devices, we hope to revitalize the second-hand market.We also want to contribute to extending battery life by reducing battery deterioration through correct usage." (Mr. Awazu)