중고전기차 배터리 성능평가와 차량가격과의 상관관계 연구

Abstract

We live in an era where each country's activities to reduce carbon dioxide emissions to prevent global warming are now a global task that everyone agrees on and empathizes with. The operation of electric vehicles, one of the important actions to accomplish this global task, is now increasingly becoming a trend. Now that 10 years have passed since the commercial launch and daily operation of electric vehicles began in earnest, it is normal for not only sales of new electric vehicles but also distribution of used electric vehicles to increase. However, unfortunately, the sale of these used electric vehicles does not yet have reasonable and effective vehicle evaluation standards, so the price formation is unstable, the distribution speed is slow, and as a result, transactions are not active.

In this research study, in order to identify these real-life problems and present a realistic evaluation model for used electric vehicles, we focused on the evaluation of the main power battery attached and installed in used electric vehicles and compared them with the vehicle prices that will be reflected in the market. The correlation was analyzed. First, we explored the direction of electric vehicle evaluation through the evaluation method and market price formation of used internal combustion engine vehicles that have been on the market for over 100 years and have over 20 million domestic vehicles in operation. Although electric vehicles have already been sold in the Korean market and more than 500,000 units are in operation, it has been difficult to obtain data for related research because battery manufacturers and vehicle manufacturers operate in closed spaces due to quality and security issues with their electric vehicle products. Coincidentally, I learned of the process of selling an electric vehicle of a bankrupt rental car company in Jeju Island through a court auction, and was able to obtain related data through a used car evaluation company that evaluated the electric vehicle. In order to secure the validity of the sample for the purpose of evaluation and correlation analysis with price using the presented materials and data, a task was carried out to ensure that conditions other than the main power battery for driving were investigated at the same or similar level as possible. The vehicle was BMW's i3 model, which was released 6-7 years ago and was operated only in one area of Jeju Island. Vehicles that were unsuitable as a sample were excluded and analyzed. First, after organizing the data Basically, to verify the validity of the sample, we verified with the given sample whether a long driving distance lowers the SOH, and a significant correlation was found with a correlation coefficient of -0.502. Next, we analyzed the correlation between SOH, a representative value representing the remaining life of the battery, and vehicle price, and found that the correlation coefficient was 0.408, which was a significant positive correlation, but not at a very high level. In the case of electric vehicles, it was determined that the normal operation of the charging system in addition to the battery was important to customer quality. A charging operability index was created and a correlation analysis was conducted, and a positive correlation of 0.409 was found, which was also a significant correlation. When analyzing the correlation with vehicle price by combining the above two, i.e., battery SOH value and charging performance index, the correlation coefficient was 0.577, showing a somewhat high correlation. In addition, a correlation analysis was conducted between the three items included as part of the electric vehicle section in the current internal combustion engine vehicle evaluation items and the operation of the drive motor with relatively few failures and the vehicle price, showing a low level of correlation with a correlation coefficient of 0.216. Lastly, the SOH value, normal operation of the charging system, and existing performance inspection items were combined in various ratios and distributed at a final ratio of 0.75:0.15:0.10, and then a correlation analysis was performed, showing the highest level of correlation of 0.586.

In conclusion, in the case of used electric vehicles, it was concluded that it is desirable to evaluate used electric vehicles by complex evaluation of not only the remaining life of the battery, but also the normal operation of the charging system and, although low probability, external evaluation such as normal connection of high power cables, which are existing evaluation items. We hope that by creating an evaluation standard for used electric vehicles centered on reasonable and effective electric vehicle batteries that will be accepted in this market, the used electric vehicle trade will become more active and further contribute to preventing global warming by reducing carbon dioxide emissions.