報告書番号

T97011

タイトル（和文）

電気自動車用シール形鉛電池の多段定電流充電法の開発

タイトル（英文）

MULTI-STEP CONSTANT CURRENT CHARGING METHOD OF EV S VALVE-REGULATED LEAD ACID BATTERIES FOR NIGHTTIME LOAD LEVELING

概要 （図表や脚注は「報告書全文」に掲載しております）

電気自動車の普及支援を行うために，夜間電力を活用でき，かつ電池の寿命を向上できる充電方法の開発を目的に電力１０社と電中研とが共同研究を実施している。電気自動車用シール形鉛電池の充電方法として，これまでに８時間以内で満充電とする２段定電流充電法の有効性と充電条件で１段目電流値を大きくすることで長寿命化が望めることを明らかにしてきた。本報告書では，さらに夜間電力を活用できる，電池寿命が長く，短時間で高効率な充電方法の開発を目的に多段定電流充電法を検討した。２段定電流法では，１段目電流値に３０Ａ付近で最適値があり，長寿命が望めることが分かった。３段法では１段目電流値の大きさによるサイクル寿命依存性はなかった。従来の２段法では７時間以上充電に要したが，４段，６段法では，５時間以下まで短縮できた。サイクル寿命も４００サイクル以上に伸ばせ，従来の２段法に比べて約３割伸ばせた。一方，段数を増やすと，正極の格子腐食を促進させる傾向が見られた。

概要 （英文）

FOR THE POPULARIZATION OF EVS,THE CONDITIONSFOR CHARGING EV BATTERIES WITH AVAILABLE CURRENT PATTERNS SHULD ALLOW COMPLETE CHARGING IN A SHORT TIME,LESS THAN FIVE TO EIGHT HOURS. THEREFORE,IN THIS STUDY,A NEW CHARGING CONDITION WAS INVESTIGATED FOR THE EV VALVE-REGULATED LEAD-ACID BATTERY SYSTEM,WHICH SHOULD ALLOW COMPLETE CHARGING OF EV BATTERY SYSTEMS WITH MULTISTEP CONSTANT CURRENS IN A MUCH SHORTER TIME WITH LONGER CYCLE LIFE AND HIGHER ENERGY EFFICIENCY COMPARED TO TWO-STEP CONSTANT CURRENT CHARGING. ALTHOUGH A HIGH MAGNITUDE OF THE FIRST CURRENT IN THE TWO-STEP CONSTANT-CURRENT METHOD PROLONGED THECYCLE LIFE BY SUPRESSING THE SOFTENING OF THE POSITIVE ELECTROD,TOO LARGE A CHARGING CURRENT MAGNITUDE DEGRADES CELLS DUE TO EXCESS INTERNAL HEAT EVOLUTION DURING CHARGING. A CHARGING CURRENT MAGNITUDE OF APPROXIMATELY 0.5C IS EXPECTED TO FURTHER PROLONG CYCLE LIFE. MULTISTEP CHARGING COULD ALSO INCREASE THE MAGNITUDE OF CHARGING CURRENT IN THE FIRST STEP WITHOUT SHORTENING THE CYCLE LIFE. FOUR- OR SIX- CONSTANT-CURRENT METHODS COULD SHORTEN THE CHARGING TIME TO LESS THAN FIVE HOURS,AS WELL AS YIELD HIGHER ENERGY EFFICIENCY AND ENHANCED CYCLE LIFE OF OVER 400 CYCLES COMPARED TO TWO-STEP CHARGING WITH THE FIRST STEP CURRENT OF 0.5C. THE CLARIFICATION OF THE DEGRADATION MECHANISM OF THE BATTERIES REVEALED THAT THE CONDITIONS OF MULTISTEP CONSTANT-CURRENT CHARGING SUPRESSED SOFTENING OF THE POSITIVE ELECTRODE AND THE FORMATION OF SULFATION PRODUSTS OF PBSO4,BUT,UNFORTUNATELY,ADVANCED CORROSION OF GRIDS IN THE POSITIVE ELECTRODE. BY ADOPTING IMPROVED GRIDS AND COOLING OF THE BATTERYSYSTEM,THE MULTISTEP CONSTANT-CURRENT METHOD MAY ENHANCE THE CYCLE LIFE.

報告者

キーワード