KR-102961362-B1 - Evaluation Method of Residual Value of High Voltage Battery for Electric vehicle

Abstract

The method for evaluating the residual value of a high-voltage battery for an electric vehicle according to the present invention comprises: an input step of BMS SOH utilizing scanner data, internal resistance per cell obtained by dividing the internal resistance of the battery pack extracted from changes in voltage and current before and after a separate load by the number of cells, internal resistance per battery cell typically displayed on the scanner, battery pack price, module price, total mileage, number of months elapsed since registration, and cumulative number of charges; a step of inputting the characteristics and remaining life of a lithium-ion battery; and a step of predicting the life according to each performance degradation by summing the input various data into SOH depreciation due to long-term use (A value depreciation) + DOD depreciation due to rough use (B value depreciation) + the largest depreciation amount depreciation due to performance degradation such as failure or performance degradation from long-term parking (C performance value depreciation). By incorporating known data related to the remaining life of lithium-ion batteries and empirical test data, and applying several pieces of information from the most commonly used automotive diagnostic scanner and the characteristics of the EV system, the method enables residual value evaluation during used car transactions as well as automotive Not only does it provide objective, rational, and factual solutions up to insurance compensation standards, but it also enables the performance of remaining lifespan evaluations in the same manner when using all-solid-state batteries in the future by modifying the reference values (standards for DOD, internal resistance, and total lifespan values for driving range).

Inventors

• 최인호
• 최진석

Dates

Publication Date

20260511

Application Date

20250819

Claims (2)

1. In a method for evaluating the residual value of a high-voltage battery for electric vehicles, The above method for evaluating the residual value of a high-voltage battery for an electric vehicle is, A step of comparing the BMS SOH (Battery Management System State Of Health), an item appearing in the data of a vehicle diagnostic scanner, and the internal resistance value of each cell of a high-voltage battery pack extracted from the changes in voltage and current per cell before and after load of the high-voltage battery with the average internal resistance value per cell of the high-voltage battery that is typically displayed on the scanner, and inputting the battery pack price, module price, total mileage, number of months elapsed since registration, and cumulative charging count into the scanner; A step of inputting the remaining life into the scanner (or computer) based on 350 to 500 cycles of the DOD of the lithium-ion battery, and It includes a step of predicting the lifespan according to each performance degradation by adding the SOH depreciation from long-term use (A value depreciation) + DOD depreciation from heavy use (B value depreciation) + the largest depreciation amount from performance degradation due to breakdown or long-term parking (C performance value depreciation), and The valuation of the above B value depreciation is, It includes a step of determining the DOD depreciation amount by calculating the DOD value based on the cumulative number of charges, driving distance, and certified fuel efficiency to define the decrease in value and calculating the Depth of Discharge (DOD) value. The valuation of the above C performance-based value depreciation is, A step of applying exponential function and proportional linear values of battery value depreciation due to failure or SOH degradation indicated on the scanner (B-SOH value), and A defective cell identification step that, after selecting a vehicle model, records the cell number and module where the DTC code for that vehicle model appeared, identifies which module corresponds to the overheated module number and the defective cell number with low cell voltage, checks for module duplication, and classifies them so that duplicates are not counted; It includes a step of determining the proportional linearization of the depreciation in value due to performance degradation caused by long-term parking aging, and The above defective cell identification step is, A step of storing the voltage per cell of a high-voltage battery pack before load, and A step of storing the base current of the high-voltage battery pack in memory before load, and A step of storing the voltage per cell and the current under load within the battery pack, which are displayed on the electric vehicle diagnostic scanner immediately after loading, into memory via the electric vehicle diagnostic scanner, and A step in which, from the above-mentioned stored memory data, each cell voltage before load - each cell voltage after load = each cell fluctuation voltage (ΔV1) is calculated, final pack current at load - pack current before load = pure load current (ΔA1) is calculated, and using this, (ΔV1/ΔA1)*1000 = internal resistance (mΩ1) per battery cell is calculated, and The method includes a step of comparing the average internal resistance value of all cells of the high-voltage battery displayed on the scanner with the internal resistance value of each cell calculated under load, determining a cell number where the internal resistance value calculated under load is higher than the average internal resistance value of all cells of the high-voltage battery as a defective cell, and deducting the value of the defective cell determined to be a defective cell. A method for evaluating the residual value of a high-voltage battery for an electric vehicle, characterized by the following.
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Description

Evaluation Method of Residual Value of High Voltage Battery for Electric Vehicle The present invention relates to a method for evaluating the residual value of a high-voltage battery for an electric vehicle. More specifically, it relates to a method for evaluating the residual value of a high-voltage battery for an electric vehicle that does not require expensive equipment and time, and which applies information from the most commonly used automotive diagnostic scanners and characteristics of the electric vehicle system to provide an objective, rational, and factual solution for evaluating the residual value during used car transactions of electric vehicles (hereinafter also referred to as 'EV') as well as automobile insurance compensation standards. Globally, environmental pollution caused by harmful gas emissions from internal combustion engine vehicles reached a critical stage, eventually leading to the gradual phase-out of diesel engines, the starting point of which was Volkswagen's "Dieselgate" in 2015. As is already known, EGR control is used to reduce nitrogen oxide emissions during vehicle operation; however, since continuous use inevitably leads to reduced engine output and increased fuel efficiency, the program was designed to disable this control during normal driving and operate only during inspections. As a result, the popularity of diesel cars plummeted, and as the fallout spread to gasoline internal combustion engines as well, interest in EVs began. As shown in FIG. 1, the EV receives DC power from a high-voltage battery (1), converts it into three-phase AC power in an inverter (HPCU) (2), controls the torque and rotational speed of the engine (3) through VVVF control, and rotates the wheels with a drive motor. Since all driving power is concentrated solely in the high-voltage battery (1), the capacity of the battery is proportional to the driving distance. High-voltage batteries, which account for more than 40% of the vehicle price, were too expensive relative to the vehicle price, and this gap was filled by hybrids (hereinafter referred to as 'HEV'). Although the main power source of an HEV is an internal combustion engine (4) like conventional ones, when starting a vehicle for a short distance (about 40 km) or when starting, a high-voltage battery (1) is used to rotate the starter. When the engine starts, the starter becomes a generator (HSG) to supply the power required for the vehicle and also charge the high-voltage battery when there is excess power. The high-voltage battery used at this time is a low-capacity, low-voltage battery that does not have a large capacity because it serves to assist in wheel driving. (Typically 48V or higher) As shown in FIG. 2, typically 75% of the driving power is provided by the internal combustion engine (4), and the remaining 25% is provided by the three-phase motor (11) of the high-voltage battery (1). Currently, almost all HEVs and EVs use lithium-ion batteries for high-voltage power, with the exception of the Japanese Prius. Research is underway on all-solid-state batteries, which offer more than three times the capacity, reduce charging time to less than one-third, and have a significantly longer lifespan, but are expensive; however, they have not yet been commercialized. Amidst this trend, the calculation of prices for used EVs and HEVs has become a matter of paramount interest. Without significant equipment and technology, the assessment of the residual value of high-voltage batteries—which account for the largest portion of the price—is unclear and ambiguous. This undermines the transparency of used car transactions and makes it extremely difficult to objectively evaluate residual value, as well as inspect performance and condition. Consequently, the price discrepancy between sellers and buyers of used HEVs and EVs has become so large that it has come to entail a major social problem. Therefore, there was an inevitable social demand for a formula that serves as a standard for calculating compensation amounts in automobile accident insurance, thereby eliminating the possibility of disputes and undermining the reliability of the used car trading market by making the most objective and empirical value judgment of high-voltage batteries. However, globally, there have been absolutely no results presented to the general market regarding standards for evaluating the residual value of high-voltage batteries; while there may be data from research conducted independently by the three domestic battery manufacturers—LG Ensol and Samsung SDI—as well as SK On, and countries such as China and the United States, utilizing massive equipment and facilities in their own laboratories, there has been no solution. The reason is that in the field, evaluating the residual value of high-voltage batteries is unimaginably uneconomical due to the unmanageable cost involved in using expensive equipment, personnel, and the manpower, time, and expense required to separate a 45