SECONDARY BATTERY DIAGNOSIS DEVICE

• Main Author: NAKAYAMA YOSHIYUKI
• Format: Patent
• Language: English; Japanese
• Published: 24.08.2017
• Subjects: BASIC ELECTRIC ELEMENTS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTINGELECTRIC POWER; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER; ELECTRICITY; GENERATION; MEASURING; MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES; PHYSICS; PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSIONOF CHEMICAL INTO ELECTRICAL ENERGY; SYSTEMS FOR STORING ELECTRIC ENERGY; TESTING

PROBLEM TO BE SOLVED: To find a highly accurate degradation rate when calculating an internal resistance value from measured values of current and voltage when a secondary battery is in use and finding a degradation rate of the secondary battery.SOLUTION: The measured time-series data of battery current Ib and battery voltage Vb of a secondary battery within a measurement period dating a fixed period Ttp back to a present time t is read from a storage unit (S100). A degree of correlation between the measured time-series data of battery current Ib and the time-series data of a reference current pattern n is calculated for each of a plurality of mutually different reference patterns (n=1 to N) (S104). When the degree of correlation is higher than a first threshold (Yes in S106), the internal resistance value R of the secondary battery is calculated on the basis of the measured time-series data of battery current Ib and battery voltage Vb, and a degradation rate of the secondary battery is calculated on the basis of comparison of the calculated internal resistance value R with an initial internal resistance value Rthat corresponds to the reference current pattern n (S110). The above process is executed at a predetermined time interval.SELECTED DRAWING: Figure 2 【課題】二次電池の使用時における電流および電圧の測定値から内部抵抗値を算出して二次電池の劣化率を求める場合に、高精度の劣化率を求める。【解決手段】記憶部から現時点ｔを起点に一定期間Ｔｔｐ遡った測定期間内の二次電池の電池電流Ｉｂおよび電池電圧Ｖｂの測定時系列データを読み出す（Ｓ１００）。互いに異なる複数の基準電流パターン（ｎ＝１〜Ｎ）のそれぞれについて、電池電流Ｉｂの測定時系列データと、基準電流パターンｎの時系列データとの相関度を算出し（Ｓ１０４）、相関度が第１閾値よりも高くなった場合（Ｓ１０６：Ｙｅｓ）には、電池電流Ｉｂおよび電池電圧Ｖｂの測定時系列データに基づいて二次電池の内部抵抗値Ｒを算出し、算出された内部抵抗値Ｒと基準電流パターンｎに応じた初期内部抵抗値ＲSnとの比較に基づいて二次電池の劣化率を算出する（Ｓ１１０）。以上の処理を、予め定められた時間の間隔で行う。【選択図】図２