JP4057276B2

JP4057276B2 - Method and apparatus for determining the state of a secondary storage battery mounted on a vehicle

Info

Publication number: JP4057276B2
Application number: JP2001329647A
Authority: JP
Inventors: 敏幸佐藤; 秀人中村; 史和岩花; 哲也加納; 徹萬ヶ原; 克己稲庭
Original assignee: THE FURUKAW ELECTRIC CO., LTD.; Furukawa Battery Co Ltd
Current assignee: THE FURUKAW ELECTRIC CO., LTD.; Furukawa Battery Co Ltd
Priority date: 2001-10-26
Filing date: 2001-10-26
Publication date: 2008-03-05
Anticipated expiration: 2021-10-26
Also published as: JP2003129927A

Description

【０００１】
【発明の属する技術分野】
本発明は、鉛蓄電池などの二次蓄電池を搭載した車両において二次蓄電池の残存容量および残存寿命（または劣化状態）など二次蓄電池の状態を判定する方法と装置に関する。
【０００２】
【従来の技術】
乗用車などの車両に搭載した鉛蓄電池などの二次蓄電池の残存容量および残存寿命（または劣化状態）を事前に検知できることは非常に有用である。
たとえば、適切なタイミングで車載の二次蓄電池の残存寿命を検知できれば、適切なタイミングで二次蓄電池を交換でき、二次蓄電池の寿命で車両が動作できなくなることを未然に防止できる。
また、環境汚染の低減および車両の燃費の向上のため、車両が交差点で信号待ちのために一時停車したとき、渋滞で停車しているときなど、内燃機関（エンジン）を停止するアイドリングストップ機能を有する車両の実用化が鋭意進められている。このようなアイドリングストップを行う場合、アイドリングストップ後に車両を再起動できるだけ車載の二次蓄電池に残存容量が存在すること、および／または、二次蓄電池の劣化状態を知ることが必要である。
【０００３】
そのような二次蓄電池としては、これまで鉛蓄電池などの蓄電池が多用されている。以下、蓄電池を車両に搭載した場合の蓄電池の残存容量および／または残存寿命（劣化状態）など蓄電池の状態を判定する従来方法と装置について述べる。
蓄電池の残存容量を測定する方法は種々試みられている。以下、従来の蓄電池の残存容量の測定方法について概観する。
【０００４】
鉛蓄電池は、放電により水を生じ、充電により硫酸を生ずるので、放電すると硫酸水溶液の比重が小さくなり、充電で硫酸水溶液の比重が元に戻る。この現象を利用して、電解液の比重を指標として残存容量を推定する方法が知られている。
しかしながら、鉛蓄電池に収容されている電解液の濃度分布が不均一になる場合がしばしばあるので、この方法では鉛蓄電池の残存容量を常に正確に推定することが出来ない。また、近年、電解液が極めて少ないシール型鉛蓄電池が採用されている。このようなシール型鉛蓄電池については電解液の比重の測定自体が困難なので、鉛蓄電池の残存容量を推定できない。
【０００５】
特開昭５３−１２７６４６号公報は、スタータクランキング時のスタータ電流と、バッテリ端子電圧との関係からバッテリの出力インピーダンスを算出し、この出力インピーダンスからバッテリの状態を検出する技術を開示している。
より詳細に述べると、特開昭５３−１２７６４６号公報は、（１）エンジンのスタートキーを回す際に生じているオルタネータの過渡的な電流値をオルタネータと車載の鉛蓄電池（バッテリ）との間に介在させた抵抗に流れる電流として計測し、さらにバッテリの端子電圧を計測し、これらの計測結果を演算増幅器で演算して車両の走行直前のバッテリの初期残存容量を求めておき、（２）さらに車両走行中の充電量あるいは充放電量を求め、（３）初期残存容量と充放電量とを比較してバッテリの残存容量を算出する方法を開示している。
しかしながら、バッテリ内の分極の影響により出力インピーダンスが大きく変化するから、大きく変化する出力インピーダンスを用いてバッテリの状態を決定することはできない。出力インピーダンスが安定するまで待機すればよいが、出力インピーダンスが安定するまで待機するには、車両を数時間以上停止させておく必要があり、実用的ではない。
【０００６】
特開平１−１２９１７７号公報は、上記特開昭５３−１２７６４６号公報に記載されている方法を改良した発明を開示している。特開平１−１２９１７７号公報に記載されている方法は、バッテリの開放電圧（開回路電圧）の変化が少なくなると出力インピーダンスが安定することに着目して、車両が停止した状態においてバッテリの開放電圧の変化が所定以下になったことを検出して、その状態における出力インピーダンスを用いてバッテリの状態を検出する方法である。
しかしながら、そのようにして算出した出力インピーダンスだけを用いても、バッテリの状態を充分正確に検出できないし、いずれにしても、バッテリの分極が安定するまで待機する必要があるのでバッテリの状態の検出に時間がかかるから、さらに短時間でバッテリの状態を検出する方法が要望されている。
【０００７】
バッテリの特性、たとえば、開放電圧はバッテリの温度に依存するが、特開昭５３−１２７６４６号公報および特開平１−１２９１７７号公報に開示されている方法は、温度依存性を考慮しておらず、バッテリの正確な状態検出には限界がある。さらに、バッテリを交換した場合などの対応が考慮されていない。特に、このような方法では、バッテリの劣化状態がバッテリ寿命のどのレベルにあるのがを判定することができない。
【０００８】
特開昭６３−２７７７６号公報は、（１）最初にバッテリを車両に搭載したときの新品のバッテリにおけるエンジン始動中の放電電荷量に対するバッテリの端子電圧降下分を実測し、（２）その後、エンジン停止と始動との間にバッテリ静特性が蘇る（分極が安定する）のに必要な時間を経過したこと、および、バッテリ残存容量が所定以上であることを条件として、車両走行ごとにエンジン始動中の放電電荷量に対するバッテリの端子電圧降下分を実測して、（３）上記初期の電圧降下分と走行後の電圧降下分を用いて演算してバッテリの寿命を予測する方法を開示している。
この方法も、上記のように、バッテリの分極が安定するまで待機しなければならず、しかも電圧降下のみを用いてもバッテリの状態を正確に検知することはできない。
【０００９】
特開平１−３９０６８号公報は、（１）スタータの起動時などの大電流放電中における互いに異なる値を示す複数時点のバッテリの放電電流と、各放電電流流出時のバッテリの端子電圧を検出し、（２）検出した電流と電圧値からバッテリの内部抵抗値と電力を算出し、（３）予め実験的に求めたバッテリの容量と内部抵抗と起電力の相関関係を表す関数を用いて算出した内部抵抗と起電力からバッテリの状態を検出する方法を開示している。
しかしながら、この方法も正確にバッテリの状態を検知できないし、この方法の処理は複雑である。
【００１０】
特許第２５３６２５７号公報（特開平４−９５７８８号公報）は鉛蓄電池の残存容量を検出するため内部インピーダンスを用いる発明を開示している。この発明においては、（１）鉛蓄電池の内部インピーダンスを測定し、（２）測定した鉛蓄電池の内部インピーダンスを、鉛蓄電池のインダクタンス成分Ｌ、電解液抵抗ＲΩ、電荷移動抵抗Ｒct、電気二重層容量Ｃｄ、ワールブルグ・インピーダンスＷ、ワールブルグ係数σからなる等価回路に当てはめて最適解を求め、（３）Ｌ、ＲΩ、Ｒct、Ｃｄ、Ｗ、σの少なくとも一つを初期の値と比較して、その相違から鉛蓄電池の寿命を判定する。
しかしながら、この発明は、発電機から鉛蓄電池への影響、自動車に搭載された装備の負荷変動などの影響を受けて鉛蓄電池の内部インピーダンスの測定が困難になる。鉛蓄電池の内部インピーダンスが測定できなければ、初期値と比較できず、寿命も判定できない。さらにこの発明を実施すると、測定装置の構成が複雑で寸法も大きくなり、価格も高くなる。
【００１１】
蓄電池から放電または充電される電流値を常時測定し、その電流測定値を積算して蓄電池の残存容量を求める方法も知られている。以下、この方法を「電流積算法」と呼ぶ。
そのような電流積算法においては、電流値の測定誤差により積算値の誤差が次第に大きくなり、蓄電池の状態が正確に求めることができなくなる。そのため、「電流積算法」を改良した方法が、特許第２７９１７５１号公報（特開平８−１９１０３号公報）、特開平９−１７１０６５号公報などに提案されている。
【００１２】
特許第２７９１７５１号公報に記載の発明は、電流積算方式と内部抵抗検出方式を併用してデータ処理して、電気自動車用鉛蓄電池の残存容量を測定する。すなわち、（１）まず、電流積算法で電気自動車に搭載された鉛蓄電池の残存容量を算出し、（２）さらに、電気自動車用鉛蓄電池の満充電完了時および自動車の走行中の一時停止時に鉛蓄電池の内部インピーダンスを測定し、（３）内部インピーダンスから導出する放電率によって電流積算法で求めた蓄電池の残存容量の値を補正する。
この方法は自動車用蓄電池の残存容量の検査法として有用であり、鉛蓄電池の残存容量を正確に知る必要がある電気自動車においては重要な技術である。
しかしながら、この発明は、電流積算法による測定に加えて、内部インピーダンスによる測定も実施する必要があり、この方法を実現する測定装置を製造した場合、装置価格が高くなる。特に、この発明は上述した内部インピーダンスを測定することが困難な事態がある。
【００１３】
特開平９−１７１０６５号公報に開示された発明は、まず、電流積算法で蓄電池の残存容量を算出しておき、その残存容量を補正する技術である。その補正残存容量の算出は、予め特定の放電電流値での定電流放電における端子電圧と残存容量のデータテーブルを準備し、自動車走行中に前記特定の放電電流値が一定時間継続したことを検知し、その時の蓄電池の端子電圧を測定し、測定した端子電圧を前記データテーブルに参照して補正のための蓄電池の残存容量を求める。
そして、算出した補正用残存容量で、事前に求めた電流積算法の残存容量を補正する。
特開平９−１７１０６５号公報に開示された発明は、電気自動車などの電動車両に搭載された蓄電池（バッテリ）の残存容量を測定するに適した技術である。その理由は、電気自動車においては、その車両が常用する走行速度での放電電流値を、上記の特定の放電電流値とすることにより蓄電池の残存容量を求める機会が多いからである。
しかしながら、特開平９−１７１０６５号公報に開示された発明は、内燃機関で動作する車両（通常の自動車）に搭載した蓄電池の残存容量に適さない。その理由は、通常の自動車においては、自動車走行中に頻繁に一定時間継続するような特定の電流値が出現する機会が少ないので、蓄電池の残存容量を求める機会が極めて少ないので、補正すべき残存容量を求めることができないからである。
【００１４】
特開平９−１７１０６５号公報に開示された発明の上記問題を解決する方法としては、たとえば、端子電圧と残存容量のデータテーブルを複数個用意し、複数の電流値で残存容量の判定を行うことも考えられる。
しかしながら、そのような方法を実施するためには、複数個のデータテーブルを用意する必要があり、処理が複雑になる。正確な残存容量の測定のためには、温度と劣化状態により該蓄電池の端子電圧と残存容量の関係が変化する場合、それに応じてさらに多くのデータテーブルを用意することが必要になるので、多量のデータを記憶させ、処理させるには複雑な装置が必要になると推察される。また、そのような多量のデータを作成する作業も厄介である。蓄電池の劣化状態の判断も難しい。
【００１５】
【発明が解決しようとする課題】
以上種々の従来技術について考察したが、それらの技術は、特に、車両に搭載した蓄電池などの二次蓄電池の状態判定に適用するには、課題がある。
【００１６】
本発明の目的は、車載の二次蓄電池の残存容量および／または残存寿命（将来寿命）を予測することができる方法および装置を提供することにある。
本発明の目的はまた、車載の二次蓄電池の種類、寸法に依存せず、二次蓄電池の残存容量および／または残存寿命を判定する方法と装置を提供することにある。
本発明はさらに、車載の二次蓄電池のメーカーが変わっても、上記目的を達成可能な、二次蓄電池の残存容量および／または残存寿命を判定する方法と装置を提供することにある。
【００１７】
【課題を解決するための手段】
本発明の基本構想について述べる。
（１）新品の二次蓄電池が車両に搭載されたとき、その時の内部抵抗（初期内部抵抗）Ｒ0 とエンジン始動の限界となる限界内部抵抗Ｒｅとを算出する。初期内部抵抗Ｒ0 は、開回路電圧Ｅの測定結果と、エンジン始動期間に二次蓄電池から流れる最大負荷時電流Ｉmax の測定値と、最大負荷時端子間電圧Ｖmax の測定値から算出する。エンジン始動の限界となる限界内部抵抗Ｒｅは、開回路電圧Ｅの測定値と、エンジンの始動限界となる下限電圧Ｖｅと、エンジン始動に要する最大負荷電力Ｗmax とから求める。
（２）その後、エンジンを始動する度に、始動期間後に、二次蓄電池の内部抵抗Ｒを算出する。この内部抵抗Ｒは、エンジン始動期間前の二次蓄電池の開回路電圧Ｅの測定値と、エンジン始動期間の二次蓄電池から流れる最大負荷電流Ｉの測定値と、エンジン始動期間の二次蓄電池の端子間電圧Ｖの測定値から算出する。この内部抵抗Ｒの算出は、エンジン始動ごとに行う。
なお上述した初期内部抵抗Ｒ0 の算出、限界内部抵抗Ｒｅの算出は、エンジン始動期間前の開回路電圧Ｅを使用することが望ましい。または、二次蓄電池を使用した後、一定期間が経過し二次蓄電池の状態が安定した後の開回路電圧Ｅを使用して行ってもかまわない。内部抵抗Ｒの算出は、一定時間が経過し二次蓄電池の状態が安定した後の開回路電圧Ｅを使用することが望ましく、またこの一定時間が経過した後に行われるエンジン始動期間前の開回路電圧Ｅを使用しても良い。また、上述した算出においては二次蓄電池の温度に応じて温度補正することが望ましい。
（３）エンジン始動ごとに内部抵抗Ｒを算出した場合、初期内部抵抗Ｒ0 と、限界内部抵抗Ｒｅと、少なくとも１つの内部抵抗Ｒを用いて残存寿命ＳＯＨを算出する。
内部抵抗と残存寿命ＳＯＨとは、たとえば、図１０に実線曲線ＣＶ１として例示したような関係があり、エンジン始動の限界となる限界内部抵抗Ｒｅのときの残存寿命ＳＯＨ＝０％とし、初期内部抵抗Ｒ0 のときの残存寿命ＳＯＨ＝１００％とすれば、内部抵抗Ｒの値から残存寿命ＳＯＨを推定できる。
【００１８】
このように、二次蓄電池を交換したときの初期状態の二次蓄電池の内部抵抗Ｒ0 とエンジン始動の限界となる限界内部抵抗Ｒｅとを算出しておき、その後、エンジン始動ごとに二次蓄電池の内部抵抗Ｒを算出し、これらのデータを用いて残存寿命ＳＯＨを正確に算出できる。
【００１９】
本発明の第１の観点によれば、（ａ）二次蓄電池が車両に搭載された初回のみ、エンジン始動期間前の二次蓄電池の開回路電圧、エンジン始動期間に二次蓄電池に流れる電流、端子間電圧を測定し、これらの測定値を用いて初期内部抵抗Ｒ0 およびエンジン始動の限界となる限界内部抵抗Ｒｅを算出し、（ｂ）二次蓄電池が車両に搭載された２回以降は、エンジン始動ごとに、エンジン始動期間前の二次蓄電池の開回路電圧、エンジン始動期間に二次蓄電池に流れる電流、端子間電圧を測定し、これらの測定値を用いて内部抵抗Ｒを算出し、（ｃ）前記初期内部抵抗Ｒ0 と、前記限界内部抵抗Ｒｅと、少なくとも１つの前記内部抵抗Ｒから残存寿命（ＳＯＨ）を算出する、処理を行って、車両に搭載された二次蓄電池の状態を判定する方法が提供される。
【００２０】
特定的には、前記初期内部抵抗Ｒ0 は下記式Ａで演算し、前記エンジン始動の限界となる限界内部抵抗Ｒｅは下記式Ｂで演算し、前記内部抵抗Ｒは下記式Ｃで演算し、前記ＳＯＨは下記式Ｄで演算する。

ＳＯＨ（％）＝〔（Ｒｅ−Ｒ）／（Ｒｅ−Ｒ０）〕×１００・・・（Ｄ）
【００２１】
Ｒ0 ＝（Ｅ２−Ｖ_ｍａｘ）／Ｉ_ｍａｘ
ただし、Ｅ２は開回路電圧であり、
Ｖ_ｍａｘは最大負荷端子間電圧であり、
Ｉ_ｍａｘは最大負荷電流である。
・・・（Ａ）
Ｒｅ＝（（Ｅ２−Ｖｅ）×Ｖｅ）／Ｗ_ｍａｘ
ただし、Ｅ２は開回路電圧であり、
Ｖｅはエンジンの始動限界となる下限電圧であり、
Ｗ_ｍａｘはエンジン始動に要する最大負荷電力である。
・・・（Ｂ）
Ｒ＝（Ｅ２−Ｖ_２）／Ｉ
ただし、Ｅ２は開回路電圧であり、
Ｖ_２は二次蓄電池が車両に搭載された２回以降の最大負荷端
子間電圧であり、
Ｉは二次蓄電池が車両に搭載された２回以降の最大負荷電流
である。
・・・（Ｃ）
ＳＯＨ（％）＝〔（Ｒｅ−Ｒ）／（Ｒｅ−Ｒ０）〕×１００
・・・（Ｄ）
【００２２】
好ましくは、前記二次蓄電池の温度を測定し、該測定した温度で、前記開回路電圧および端子間電圧を補正する。
【００２３】
さらに好ましくは、前記算出された複数の内部抵抗をエンジン始動回数を変数として近似式を計算して現在の内部抵抗を算出し、現在の内部抵抗、前記初期内部抵抗Ｒ0 と、前記限界内部抵抗Ｒｅから前記ＳＯＨを算出する。
【００２４】
好ましくは、前記二次蓄電池の内部抵抗が前記初期内部抵抗の値のときのＳＯＨを１００％とし、前記二次蓄電池の内部抵抗が前記限界内部抵抗Ｒｅの値のときのＳＯＨを０％とし、前記内部抵抗に応じたＳＯＨを％で表す。
【００２５】
好ましくは、前記処理は、前記二次蓄電池の使用後、前記二次蓄電池の状態が安定する期間を経過した後行う。
【００２６】
好ましくは、前記二次蓄電池は鉛蓄電池である。
【００２７】
本発明の第２の観点によれば、上記方法を実施する手段を備えた装置が提供される。
【００２８】
本発明の第３の観点によれば、さらに、車両に搭載された二次蓄電池の電圧を測定する電圧計と、前記二次蓄電池に流れる電流を検出する電流計と、エンジンの始動を示す信号を生成するエンジン始動信号生成手段とを備えた装置が提供される。
【００２９】
【発明の実施の形態】
第１実施の形態
本発明の第１の実施の形態として、車両の走行中に、渋滞または交差点などで一時停車中に内燃機関（エンジン）を停止する、いわゆるアイドリングストップ機能を有する車両に搭載された二次蓄電池の残存容量および劣化状態を判定する方法とその装置、および、二次蓄電池の残存容量および劣化状態の判定結果に基づいてアイドリングストップの処理を行う方法と装置について述べる。
【００３０】
図１は本発明の第１実施の形態の二次蓄電池の残存容量および／または劣化状態を判定する装置（以下、残存容量・劣化状態判定装置）の構成図である。
車両、たとえば、普通の乗用車には、バス９を介して接続されているスタータ１、発電機（オルタネータ）２、二次蓄電池３、電気装備４、および、エンジン５が搭載されている。
二次蓄電池３としては、以下、鉛蓄電池を用いた場合について述べる。
電気装備４は、たとえば、照明灯、方向指示灯、ハザードランプなどの各種ライト（ランプ）、ミラー駆動モータ、操作パネル、空調機など電気で動作する車両に搭載されたものを総称している。
【００３１】
図１に図解した残存容量・劣化状態判定装置は、鉛蓄電池３の温度を測定する温度センサ６と、鉛蓄電池３の端子電圧を測定する電圧計７と、二次蓄電池３に流れる電流を測定する電流計８と、鉛蓄電池３の残存容量・劣化状態を算出する演算手段１０と、演算手段１０の結果をを表示する表示手段１６を有する。
図１に図解した残存容量・劣化状態判定装置には、演算手段１０の結果に応じた車両の駆動制御処理を行う制御手段１２を含めることができる。
【００３２】
さらに、演算手段１０の結果に応じてアイドリングストップ（ＩＳ）処理を行うアイドリングストップ（ＩＳ）処理手段１４を含めることができ、この場合、残存容量・劣化状態判定装置はアイドリングストップ処理機能を有する、二次蓄電池の残存容量および／または劣化状態を判定する装置となる。
【００３３】
スタータ１は車両の始動時に鉛蓄電池３からの給電によりエンジン５を動作させる電力を提供する。オルタネータ２は車両が始動してエンジン５が回転動作すると起動して発電を行う。オルタネータ２の発電により電気装備４への給電が行われる他、鉛蓄電池３が充電される。
【００３４】
本発明のエンジン始動信号生成手段として、たとえば、スタータ起動スイッチ信号ＳＷ１、オルタネータ起動スイッチ信号ＳＷ２、エンジン起動スイッチ信号ＳＷ５が演算手段１０に入力されている。これらのスイッチ信号の全ては必要でないが、エンジンの始動を示す信号を演算手段１０に入力する。
【００３５】
温度センサ６は鉛蓄電池３の温度を測定し、後述するように、温度センサ６で測定した温度を鉛蓄電池３の端子間電圧の補正などに用いる。
温度センサ６の測定部位は、温度補正を行う基準温度に依存する。正確には鉛蓄電池３の電解液の温度を基準温度として、温度センサ６で電解液の温度を測定することが望ましい。基準温度が鉛蓄電池３の外壁の場合は、温度センサ６で鉛蓄電池３の外壁を測定する。基準温度が鉛蓄電池３が設置されている車内の場合は温度センサ６で鉛蓄電池３が設置されている車内の温度を測定する。
また、基準温度が鉛蓄電池３の電解液の温度である場合、たとえば、温度センサ６で鉛蓄電池３の外壁の温度を測定し、演算手段１０においてその測定温度から電解液の温度を推定することもできる。
温度センサ６の測定部位はこのように基準温度に依存するが、以下、温度センサ６の温度測定部位にはこだわらず、広い意味で温度センサ６で鉛蓄電池３の温度を測定する。
温度センサ６は、測定部位にも依存するが、鉛蓄電池３の温度範囲が−３０〜１００°Ｃ程度であるから、このような温度測定に適し、占有場所をとらず、低価格で、扱いの容易な温度センサ、たとえば、銅・コンスタンタン熱電対など、または白金抵抗体などを用いることができる。また、鉛蓄電池３には温度センサ６が内蔵されている場合があり、その場合はその温度センサを用いることができる。
【００３６】
電圧計７は鉛蓄電池３の端子間電圧または開放電圧を測定するものであり、通常の直流電圧計を用いることができる。電圧計７による測定範囲はたとえば、０〜５０ＶＤＣである。
なお、鉛蓄電池３の端子間電圧とは、鉛蓄電池３の低電位レベル、たとえば、接地電圧と高電位レベル、たとえば、鉛蓄電池３の電気装備４側の電位との間の電圧を言う。この端子間電圧を電圧計７で測定する。
【００３７】
表示手段１６は、演算手段１０の結果を車両のドライバなどに表示して示す装置であり、たとえば、車両のダッシュボード部分に設けた液晶表示器であり、普通乗用車の操作パネル部分の表示器と兼用することもできる。
【００３８】
図２は図１に図解した演算手段１０の具体的な構成例を示す図である。
演算手段１０は、マイクロコンピュータの中央演算処理装置（ＣＰＵ）１００と、ＣＰＵ１００で動作する各種プログラムおよび各種パラメータが記憶されているＲＯＭ１０２と、ＣＰＵ１００で行う処理の途中結果の記憶、および、各種パラメータの記憶に使用するＲＡＭ１０４と、アナログ信号として入力される温度センサ６、電圧計７および電流計８の検出信号を入力してディジタル信号に変換するＡ／Ｄ変換部（Ａ／ＤＣ）１０６と、ディジタル信号として入力されるスタータ起動スイッチ信号ＳＷ１、オルタネータ起動スイッチ信号ＳＷ２およびエンジン起動スイッチ信号ＳＷ５を入力するディジタル入力部（ＤＩ部）１０８と、ＣＰＵ１００の結果を制御手段１２およびアイドリングストップ（ＩＳ）処理手段１４に出力したり、制御手段１２およびＩＳ処理手段１４からの信号を入力する通信インタフェース（Ｉ／Ｆ）１１２と、ＣＰＵ１００から表示手段１６に表示情報を出力する表示インタフェース（ＤＳＰＩ／Ｆ）１１４とを有する。
【００３９】
Ａ／Ｄ変換部（Ａ／ＤＣ）１０６の入力電圧範囲は、たとえば、０〜５Ｖ程度である。
温度センサ６として熱電対を用いた場合のように、その検出電圧が、たとえば、０〜２０ｍＶ程度と非常に低い時は、Ａ／ＤＣ１０６の前段の回路で、０〜５Ｖに増幅する。
電流計８の検出電流が、たとえば、０〜１Ｖ程度の信号として出力されるときは、Ａ／ＤＣ１０６の前段の回路で、０〜５Ｖに増幅する。
同様に、電圧計７の検出電圧が、たとえば、０〜１Ｖ程度の低いときは、Ａ／ＤＣ１０６の前段の回路で、０〜５Ｖに増幅する。
【００４０】
図３は図１および図２に図解した演算手段１０、特に、ＣＰＵ１００で行う処理を図解したフローチャートである。
以下、演算手段１０の動作を述べる。より具体的には、ＣＰＵ１００がＲＯＭ１０２に記憶されている各種プログラムに従って下記に述べる処理を行う。
【００４１】
ステップ１：劣化判定処理の可否の判定
演算手段１０（ＣＰＵ１００）は、鉛蓄電池３が前回使用した後、第１の所定時間ｔ６１が経過したか否かをチェックする。
鉛蓄電池３が第１の所定時間ｔ_１が経過したか否かの処理は、ＣＰＵ１００が鉛蓄電池３の使用後、タイマ１１０を駆動して、たとえば、１秒ごと定期的にタイマ１１０の計時時間を読み取ってＲＡＭ１０４に記憶し、ＲＡＭ１０４の計時情報を読みだしてタイマ１１０の計時時間が第１の所定時間ｔ_１を経過したか否かをチェックする。
ＣＰＵ１００は鉛蓄電池３の使用後、第１の所定時間ｔ_１が経過前はステップ２を経由してステップ１２の処理に移行し、鉛蓄電池３の使用後、第１の所定時間ｔ_１経過後はステップ３以降の劣化判定処理を行う。
【００４２】
ステップ２、鉛蓄電池３の使用後、上記第１の所定時間ｔ_１が経過していない場合は、ＣＰＵ１００は鉛蓄電池３の劣化判定処理を行わず、ステップ１２の処理に移行する。この場合、後述するステップ１２では、前回のステップ１１で計算した、鉛蓄電池３の内部抵抗、すなわち、出力内部抵抗値、Ｒ値が使用される。
【００４３】
所定時間待機の意味
鉛蓄電池３の使用後、第１の所定時間ｔ₁ 経過前は鉛蓄電池３の劣化判定処理を行わない理由について述べる。
図４は鉛蓄電池の開回路電圧が安定する状態を示すグラフである。
図４に図解したように、同程度の劣化度合いの鉛蓄電池を充電・放電によって同一のＳＯＣ（充電容量）に調整した後、開回路電圧Ｅ１が安定するには第１の所定時間ｔ₁ だけ経過するまで待機することが必要であるから、より正確な開回路電圧Ｅ１を測定するには安定する第１の所定時間ｔ₁ だけ待機する必要がある。
第１の所定時間ｔ₁ は、図４に図解したように、開回路電圧Ｅ１が安定するに充分な時間であり、たとえば、数時間である。
【００４４】
ステップ３：開回路電圧の測定と温度補正
ＣＰＵ１００は、電圧計７の測定値および温度センサ６の検出値をＡ／ＤＣ１０６を介して入力する。電圧計７の測定値は、鉛蓄電池３の開回路電圧Ｅ１を示している。
なお、開回路電圧（開放電圧）Ｅ１とは、車両が停止し、電気装備４の全ての負荷がオフになったときのバス９に接続されている二次蓄電池３の電圧である。
【００４５】
開回路電圧Ｅ１は、図５に例示したように温度依存性がある。図５は温度・開回路電圧特性曲線を示すグラフである。
そこで、ＣＰＵ１００は温度センサ６の検出結果で開回路電圧Ｅ１の温度補正を行う。なお、開回路電圧Ｅ１を温度に依存させて正確に求めるための処理であるから、この温度補正は必須ではないが、開回路電圧Ｅ１の温度補正を行うことが望ましい。
【００４６】
温度補正の具体的な方法について述べる。
（１）事前に、車両に実際に搭載する鉛蓄電池３について、または鉛蓄電池３の代表的なものについて、種々の温度についての開回路電圧Ｅ１を測定して、図５の温度・開回路電圧特性曲線を求める。
（２）次いで、基準温度、たとえば、２５°Ｃの開回路電圧Ｅ１の温度補正係数α１６Ｔを１．０とし、図５の曲線に基づく値をプロットして、温度センサ６の検出値が基準温度以上のときは１．０未満の温度補正係数α１_Ｔ、温度センサ６の検出値が基準温度以下のときは１．０以上の温度補正係数α１_Ｔを変数とする開回路電圧・温度補正係数α１_Ｔの曲線を求める。
（３）次いで下記式１に基づいて電圧計７で測定した開回路電圧Ｅ１を補正する。
【００４７】

【００４８】
なお、温度補正係数α１_T としては、図５の特性からほぼ一定の傾きを示していると考えてよいので、温度補正係数α１_T ＝ａ（一定値）とすることもできるし、より正確な温度補正係数α１_T を算出して用いることもできる。
より正確な温度補正係数α１_T の算出方法について述べる。測定した温度・開回路電圧特性曲線を、測定した温度と測定した開回路電圧に基づきテーブル化し、ＲＯＭ１０２またはＲＡＭ１０４に温度補正係数α１_T の値を記憶する。ＣＰＵ１００はＲＯＭ１０２またはＲＡＭ１０４にテーブル化した温度補正係数α１_T を、温度センサ６の検出温度を変数として読み出す。なお、温度センサ６の検出温度が事前にプロットした温度以外の場合は、その両側のプロットに使用した温度の温度補正係数α１_T を参照して補間して検出温度に対応する温度補正係数α１_T を求める。
【００４９】
温度補正した開回路電圧Ｅ２はＳＯＣ状態によって変化する。その例を図６に示す。図６は、基準温度がたとえば、２５°における、ＳＯＣ／％を横軸にとり、温度補正開回路電圧Ｅ２を縦軸にとった、ＳＯＣ（％）・開回路電圧特性曲線を示すグラフである。
図６に例示したＳＯＣ（％）・開回路電圧特性曲線について述べると、鉛蓄電池３の場合、開回路電圧は電解液を構成する硫酸の比重に比例して変化するのは、充放電によって電解液を構成する硫酸の比重が変化するためである。
【００５０】
ステップ４：エンジンの始動の検出
ＣＰＵ１００は、エンジン５が始動されることを検出する。エンジン５の始動の検出は、たとえば、スタータ１の始動を示すスタータ起動スイッチ信号ＳＷ１、または、エンジン５の始動を示すエンジン起動スイッチ信号ＳＷ５がディジタル入力部（ＤＩ部）１０８を介して入力された時をもって検出することができる。
【００５１】
ステップ５：エンジン始動時の最大負荷電流、最大負荷端子間電圧、鉛蓄電池の温度測定、および、最大負荷端子間電圧の温度補正
エンジン５の始動を検出したら、ＣＰＵ１００はエンジン５の始動時の、最大負荷電流Ｉ_max 、最大負荷端子間電圧Ｖ_max1、および、そのときの鉛蓄電池３の温度を検出する。最大負荷電流Ｉ_max は電流計８の検出値を、最大負荷端子間電圧Ｖ_max1の測定値を、鉛蓄電池３の温度は温度センサ６の検出値を、Ａ／ＤＣ１０６を介して入力することによって得られる。
【００５２】
エンジン５の始動時とは、図７に例示したように、エンジン５の始動に伴って鉛蓄電池３から短時間大電流が流れる期間、たとえば、数秒の期間を言い、より正確には、鉛蓄電池３に負電流が流れ初めてからオルタネータ２が作動して正電流が流れるまで期間を言う。
図７はエンジン始動時の時間経過に伴う電流の変化を示す時間・電流変化特性を示すグラフである。
【００５３】
図８は、エンジン始動時間と鉛蓄電池３の内部抵抗との関係を示す特性図である。このエンジン５の始動時間は、鉛蓄電池３の内部抵抗とある程度の相関関係があるものの、劣化が進むと、エンジン始動時間のみが大きくなる。鉛蓄電池３が極度に劣化するとエンジン始動時の電流を十分に流すことができないためエンジン始動時間が非常に長くなる。また、電流の大きさが小さく、端子間電圧もあまり低下しないことから、最大負荷時の内部抵抗は大きくならないという現象が起こる。
【００５４】
最大負荷端子間電圧Ｖ _ｍａｘ１の温度補正
ＣＰＵ１００は、好ましくは、上記検出した鉛蓄電池３の温度を用いて上記電圧計７で測定した最大負荷端子間電圧Ｖ_ｍａｘ１の温度補正を行う。
図９は鉛蓄電池３の温度変化を横軸にとり、最大負荷端子間電圧Ｖ_１の測定値を縦軸にとった温度変化・最大負荷端子間電圧特性を示すグラフである。
最大負荷端子間電圧Ｖ_ｍａｘ１を温度補正する必要性について述べる。たとえば、寒冷地において低温時に鉛蓄電池３の最大負荷端子間電圧を測定した場合、スタータ１の始動時に検出した鉛蓄電池３の最大端子間電圧は常温の時、たとえば、２５°Ｃのときの最大端子間電圧の測定値より低くなる。したがって，たとえば、常温を基準温度として、最大端子間電圧を温度補正しないままその最大端子間電圧を用いて、後述する鉛蓄電池３の内部抵抗を計算すると、その時の鉛蓄電池３の内部抵抗は常温時の内部抵抗よりも大きくなり、正確な内部抵抗が求められない。その結果、正確な鉛蓄電池３の劣化判定ができない。そこで、ＣＰＵ１００において、最大負荷端子間電圧Ｖ_ｍａｘ１の温度補正を行う。
【００５５】
かりに常時、常温状態で車両を使用するような場合で、上述した鉛蓄電池３の端子間電圧、特に、最大負荷時の端子間電圧が上述した変化を示さない場合には、これから述べる、最大負荷時の端子間電圧の温度補正は必要がない。
【００５６】
以下、最大負荷端子間電圧Ｖ_ｍａｘ１を温度補正する処理について述べる。
この場合も、図５を参照して述べた、検出温度における開回路電圧・温度補正係数α１_Ｔを求めて開回路電圧Ｅ１を温度補正したと同様の処理を行う。
（１）まず、いくつかの温度おける最大負荷端子間電圧Ｖ_１を測定して、図９に図解した特性曲線を事前に求める。
（２）次いで、基準温度、たとえば、２５°Ｃの最大負荷端子間電圧Ｖ_１の温度補正係数α２_Ｔを１．０とし、図９の曲線に基づく値をプロットして、温度センサ６の検出値が基準温度以上のときは１．０以上の温度補正係数α２_Ｔ、温度センサ６の検出値が基準温度以下のときは１．０未満の温度補正係数α２_Ｔを検出温度を変数とする曲線を求める。
（３）さらに、温度・最大負荷端子間電圧の温度補正係数α２_Ｔをテーブル化し、ＲＯＭ１０２またはＲＡＭ１０４に最大負荷端子間電圧温度補正係数α２_Ｔの値を記憶する。
（４）ＣＰＵ１００はＲＯＭ１０２またはＲＡＭ１０４にテーブル化した最大負荷端子間電圧温度補正係数α２_Ｔを、温度センサ６の検出温度を変数として読み出す。なお、温度センサ６の検出温度が事前にプロットした温度以外の場合は、その両側のプロットに使用した温度の温度補正係数α２_Ｔを参照して補間して検出温度に対応する温度補正係数α２_Ｔを求める。
（５）下記式２を用いて電圧計７で測定した最大負荷端子間電圧Ｖ_ｍａｘ１をその時に温度センサ６で検出した鉛蓄電池３の温度で補正する。
【００５７】

【００５８】
ステップ６：鉛蓄電池３が新品か否かの判定
新しい鉛蓄電池３を交換したとき、車両の整備員などがＲＡＭ１０４に鉛蓄電池３を交換したことを示すフラグをフラグ＝０と設定しておく。
ＣＰＵ１００は、そのフラグを読み出し、フラグ＝０の場合は、新品の鉛蓄電池３が交換されたことを検出する。その場合、ＣＰＵ１００は、ステップ７、８の処理に移行する。
ＣＰＵ１００はＲＡＭ１０４のフラグが０でないとき、すなわち、フラグ＝１のときはステップ９の処理に移行する。
【００５９】
ステップ７、８：新品の鉛蓄電池の内部抵抗計算と保存
ＣＰＵ１００はフラグ＝１に設定し、次回から新品の鉛蓄電池３の処理を行わないようにする。
ＣＰＵ１００は、下記式３に基づいて、新品の鉛蓄電池３の内部抵抗、すなわち、初期内部抵抗Ｒ0 を計算し、さらに、下記式４に基づいてエンジン始動の限界となる限界内部抵抗Ｒｅを計算する。
【００６０】

【００６１】

【００６２】
車両に搭載した鉛蓄電池のエンジン始動に要する最大負荷電力Ｗ_max は、同一車両であれば、ほぼ一定であり、事前に測定した最大負荷電力Ｗ_max を、同じ機種の車両に共通して用いる。この最大負荷電力Ｗ_max は、ＲＯＭ１０２またはＲＡＭ１０４に記憶しておく。
【００６３】
ステップ８：初期内部抵抗Ｒ０および限界内部抵抗Ｒｅの保持
ＣＰＵ１００は、計算した新品の鉛蓄電池３の内部抵抗、すなわち、初期内部抵抗Ｒ０、および、エンジン始動の限界となる限界内部抵抗ＲｅをＲＡＭ１０４に記憶して、保存する。ＣＰＵ１００はその後、ステップ１２の処理に移行する。
【００６４】
ステップ９：エンジン始動時間変化の判定
ＣＰＵ１００は、電流計８で検出したエンジン始動時間Δｔがある一定値、たとえば２秒以上か否かをチェックする。図７に示したエンジン始動時間Δｔは、鉛蓄電池３の内部抵抗とある程度の相関関係があるものの、劣化が進むと、エンジン始動時間Δｔのみが大きくなる。鉛蓄電池３が極度に劣化するとエンジン始動時の電流を十分に流すことができないためエンジン始動時間Δｔが非常に長くなる。また、電流の大きさが小さく、端子間電圧もあまり低下しないことから、最大負荷時の内部抵抗は大きくならないという現象が起こる。
図８は、エンジン始動時間と鉛蓄電池３の内部抵抗との関係を示す特性図である。
そのため、エンジン始動時の内部抵抗と始動時間を測定し、通常は、内部抵抗を用いて劣化判定を行い、エンジン始動時間Δｔがある値以上の場合には、ＳＯＨを０％と判定する。エンジン始動時間Δｔがある一定値以上の場合は、ＣＰＵ１００はステップ１０の処理に移行する。エンジン始動時間Δｔがある一定値以下の場合は、ＣＰＵ１００はステップ１１の処理に移行する。
【００６５】
ステップ１０：残存寿命無しの出力
ＣＰＵ１００は、鉛蓄電池３の残存寿命がないと判定し、ＳＯＨ＝０％、残寿命＝０として、この情報を制御手段１２、ＩＳ処理手段１４、および、表示手段１６に出力する。
たとえば、表示手段１６には、「ＳＯＨ＝０％、残寿命＝０」がメッセージとして表示される。
なお、本実施の形態においては、図１０に例示したように、鉛蓄電池３の内部抵抗がエンジン始動の限界となる限界内部抵抗Ｒｅのとき、ＳＯＨ＝０％として、鉛蓄電池３の内部抵抗が初期内部抵抗Ｒ0 のとき、ＳＯＨ＝１００％としている。このように、ＳＯＨを０〜１００％表記することができるので、ユーザーにとって鉛蓄電池３の状態が非常に判りやすい。
【００６６】
ステップ１１：二次蓄電池が車両に搭載された２回以降の最大負荷電流、最大負荷端子間電圧、温度測定、最大負荷端子間電圧の温度補正、および、内部抵抗の算出
ＣＰＵ１００は、ステップ５における処理と同様、ただし、今回はエンジンの始動時ではなく二次蓄電池が車両に搭載された２回以降の最大負荷電流Ｉ、最大負荷端子間電圧Ｖ₁ 、および、そのときの鉛蓄電池３の温度を検出する。最大負荷電流Ｉは電流計８の検出値を、最大負荷端子間電圧Ｖ₁ は電圧計７の測定値を、鉛蓄電池３の温度は温度センサ６の検出値を、Ａ／ＤＣ１０６を介して入力することによって得られる。
次いで、ＣＰＵ１００は、好ましくは、上記検出した鉛蓄電池３の温度を用いて上記電圧計７で測定した最大負荷端子間電圧Ｖ₁ の温度補正を、図９を参照して述べた、式５に従って、行う。図９を参照して述べた温度補正係数α２_T はこの温度補正にも用いる。
【００６７】

【００６８】
鉛蓄電池の内部抵抗の計算
ＣＰＵ１００は、下記式６に基づいて、鉛蓄電池３の内部抵抗、すなわち、出力内部抵抗Ｒを計算する。
【００６９】

【００７０】
ステップ１２：ＳＯＨの計算
ＣＰＵ１００は、式３を適用して算出した鉛蓄電池３を交換した直後の初期内部抵抗Ｒ０、式６を適用して算出した鉛蓄電池３の内部抵抗Ｒと、式３を適用した算出したエンジン始動の限界となる限界内部抵抗Ｒｅとから、式７に従って、鉛蓄電池３の劣化状態を示す指標ＳＯＨを計算する。
【００７１】
ＳＯＨ（％）＝〔（Ｒｅ−Ｒ）／（Ｒｅ−Ｒ０）〕×１００・・・（７）
【００７２】
その後、ＣＰＵ１００は、算出したＳＯＨ（％）を制御手段１２および表示手段１６に出力する。
制御手段１２は劣化状態を示す指標ＳＯＨ（％）をメッセージ表示する。
【００７３】
ステップ１３：内部抵抗の反復算出
ＣＰＵ１００は、エンジン５が始動される度、ステップ１１における処理、すなわち、（１）鉛蓄電池３が車両に搭載された２回以降のエンジン始動期間前の開回路電圧、エンジン始動期間の最大負荷電流、最大負荷端子間電圧の測定、および、温度測定を行い、さらに、（２）最大負荷端子間電圧の温度補正を行い、（３）これらの結果を用いて、上記同様内部抵抗の算出を行う。また、ＣＰＵ１００は、算出した内部抵抗Ｒをその処理回数とともに、ＲＡＭ１０４に記憶していく。
【００７４】
ステップ１４：寿命予測
図１０はエンジン始動回数と出力内部抵抗との関係を示す特性、および、出力内部抵抗とＳＯＨとの関係を図解したグラフである。
実線で示した曲線ＣＶ１は、ステップ１３において算出した複数回のエンジン５の始動に対してその都度算出した内部抵抗Ｒを、ＣＰＵ１００において、プロットしたものである。
破線で示した曲線ＣＶ２は、事前に代表的な鉛蓄電池について算出した内部抵抗Ｒをプロットしたものである。この曲線ＣＶ２の値は、ＲＯＭ１０２またはＲＡＭ１０４に記憶されている。通常は、ＲＯＭ１０２に記憶しておき、修正が容易に行えるようにしている。
【００７５】
図１０に図解の特性から、出力内部抵抗からＳＯＨを推定できることが判る。したがって、ＣＰＵ１００は、エンジン５の始動に則して鉛蓄電池３の内部抵抗を上述した方法で計算し、ＲＡＭ１０４に記憶されている複数の内部抵抗を測定回数、すなわち、エンジン５の始動回数ごとにプロットして、プロットした複数の内部抵抗を、たとえば、二次多項式近似して、二次多項式近似したものから現在の内部抵抗を算出する。次いで、ＣＰＵ１００は、近似したものから算出した内部抵抗と、ステップ７において算出されＲＡＭ１０４に記憶されているエンジン始動の限界となる限界内部抵抗Ｒｅと初期内部抵抗Ｒ０とを式７に代入して、劣化状態を示す指標ＳＯＨを算出する。
【００７６】
そしてさらにＣＰＵ１００は算出した劣化状態を示す指標ＳＯＨを、制御手段１２、ＩＳ処理手段１４および表示手段１６に出力する。
表示手段１６は劣化状態を示す指標ＳＯＨを、たとえば、メッセージ表示する。
【００７７】
制御手段１２はＣＰＵ１００（演算手段１０）から出力された劣化状態を示す指標ＳＯＨを参照して、車両の運転、保守などに反映させることができる。
たとえば、車両のドライバまたは整備士が現在の鉛蓄電池３の劣化状態を示す指標ＳＯＨを知りたいときは、図示しない操作部を介して制御手段１２にアクセスして制御手段１２に保存されている劣化状態を示す指標ＳＯＨを、たとえば、制御手段１２を介して表示手段１６または車両の操作パネルの表示部に表示してＳＯＨを確認することができる。その結果、適切なタイミングが鉛蓄電池３を交換することができる。
あるいは、車両に何らかの故障が発生した場合、制御手段１２は演算手段１０で算出した劣化状態を示す指標ＳＯＨをチェックして、その不具合の原因が鉛蓄電池３のＳＯＨが低いために起きたか否かを診断できる。
【００７８】
また、アイドリングストップ（ＩＳ）処理手段１４も、演算手段１０で算出した劣化状態を示す指標ＳＯＨを参照して、アイドリングストップ可能か否かの判定をすることができる。
【００７９】
表示手段１６への表示は、劣化状態を示す指標ＳＯＨの表示に限らず、種々の表示を行うことができる。たとえば、保守点検時などのときには、上述した処理状態の途中結果、たとえば、鉛蓄電池３の温度、開回路電圧Ｅ１、最大負荷時電圧、最大負荷時電流、内部抵抗値、エンジン始動の限界となる限界内部抵抗Ｒｅ、途中の劣化状態を示す指標ＳＯＨなどを表示手段１６で表示することができる。
【００８０】
以上のように、本発明の第１実施の形態によれば、図１に図解したように、温度センサ６、電圧計７および電流計８を設け、演算手段１０で上述した処理を行うことにより、鉛蓄電池３の劣化状態を示す指標ＳＯＨを算出することができる。
すなわち、本実施の形態においては、新品の鉛蓄電池３を車両に搭載したときから、基準となる、鉛蓄電池３の初期内部抵抗Ｒ0 とエンジン始動の限界となる限界内部抵抗Ｒｅとを算出しておき、その後、エンジンの始動の度に鉛蓄電池３の現在の内部抵抗を算出し、鉛蓄電池３の内部抵抗が初期内部抵抗Ｒ0 のときＳＯＨを１００％、鉛蓄電池３の内部抵抗が限界内部抵抗Ｒｅのとき残存寿命ＳＯＨを０％として、式７によって現在の内部抵抗によってＳＯＨがどの値になるかを決定しているので、正確にＳＯＨを求めることができる。
【００８１】
特に、本実施の形態においては、鉛蓄電池３の動作状態が安定してから処理を行っているで、正確にＳＯＨを求めることができる。
【００８２】
さらに本実施の形態においては、鉛蓄電池３の温度を測定し、測定した温度で鉛蓄電池３の電圧を補正しているので、より正確なＳＯＨを算出することができる。
【００８３】
さらに本実施の形態においては、エンジン始動の度に内部抵抗を算出し、図１０に例示したように、複数の内部抵抗をプロットして、プロットしたそれらを、たとえば、多項式近似して用いるので、一層正確にＳＯＨを算出することができる。
【００８４】
本実施の形態においては、鉛蓄電池３が交換されるたび、初期内部抵抗Ｒ0 と限界内部抵抗Ｒｅを求めるので、鉛蓄電池３の交換があっても問題はない。
本実施の形態においては、式４で用いる下限電圧Ｖe および鉛蓄電池３の始動に要する最大負荷電力Ｗmax のみ設定すれば、二次蓄電池のメーカー、種類に無関係にＳＯＨを算出することができる。
【００８５】
以上のように、本実施の形態によれば、常時ＳＯＨを算出することができるから、鉛蓄電池３の残存寿命が予測でき、適切なタイミングで鉛蓄電池３を交換することも可能となる。
また、算出したＳＯＨを用いてアイドリングストップ処理を行うこともできる。
【００８６】
なお本実施の形態の実施に際しては、特別複雑な構成要素を必要とせず、信号処理も複雑ではないので、容易かつ低価格で実用化できる。
【００８７】
以上の実施の形態においては、二次蓄電池３として鉛蓄電池を用いた場合について述べたが、本発明は鉛蓄電池に適用が限定されるわけではなく、充電可能な種々の二次蓄電池に適用できる。
【００８８】
上述した実施の形態は例示であり、本発明の適用に際しては、図面を参照して述べた実施の形態および上記記述に限定されず、明細書および図面に記載された内容に基づいて当業者が想起しうるものは本発明に属すると考えるべきである。
【００８９】
本発明によれば、簡単な方法および簡単な構成で二次蓄電池の残存寿命ＳＯＨを算出できる。さらに本発明で、ＳＯＨを０〜１００％表記することができるので、ユーザーにとって非常に判りやすい。
【００９０】
本発明の方法および装置は、二次蓄電池の交換があっても、二次蓄電池のＳＯＨを算出できる。
【００９１】
本発明の方法および装置は、二次蓄電池の種類、メーカー、特性に依存しないで二次蓄電池のＳＯＨを算出できる。
【図面の簡単な説明】
【図１】図１は本発明の第１実施の形態の二次蓄電池の残存容量および／または劣化状態を判定する装置構成図である。
【図２】図２は図１に図解した演算手段の装置構成の具体例を図解した図である。
【図３】図３は図１および図２に図解した二次蓄電池の残存容量および／または劣化状態を判定する装置の動作を示すフローチャートである。
【図４】図４は鉛蓄電池の開回路電圧が安定する状態を示すグラフである。
【図５】図５は温度・開回路電圧特性曲線を示すグラフである。
【図６】図６は基準温度がたとえば、２５°における、ＳＯＣ／％を横軸にとり、温度補正開回路電圧を縦軸にとった、ＳＯＣ／％・温度補正開回路電圧特性曲線を示すグラフである。
【図７】図７はエンジン始動時の時間経過に伴う電流の変化を示す時間・電流変化特性を示すグラフである。
【図８】図８はエンジン始動時間と鉛蓄電池の内部抵抗との関係を示す特性図である。
【図９】図９は鉛蓄電池の温度変化を横軸にとり、最大負荷端子間電圧Ｖ₁ の測定値を縦軸にとった温度変化・最大負荷端子間電圧特性を示すグラフである。
【図１０】図１０はエンジン始動回数と出力内部抵抗との関係を示す特性、および、出力内部抵抗とＳＯＨとの関係を図解したグラフである。
【符号の説明】
１・・スタータ、ＳＷ１・・スタータ起動スイッチ信号
２・・オルタネータ、ＳＷ２・・オルタネータ起動スイッチ信号
３・・二次蓄電池（鉛蓄電池）、４・・電気装備
５・・エンジン、ＳＷ５・・エンジン起動スイッチ信号
６・・温度センサ、７・・電圧計、８・・電流計、９・・バス
１０・・演算手段
１００・・ＣＰＵ、１０２・・ＲＯＭ、１０４・・ＲＡＭ
１０６・・Ａ／Ｄ変換部（Ａ／ＤＣ）
１０８・・ディジタル入力部（ＤＩ）、１１０・・タイマ
１１２・・通信インタフェース（Ｉ／Ｆ）１１２
１１４・・表示インタフェース（ＤＳＰＩ／Ｆ）１１４
１２・・制御手段
１４・・アイドリングストップ（ＩＳ）処理手段
１６・・表示手段[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for determining a state of a secondary storage battery such as a remaining capacity and a remaining life (or deterioration state) of the secondary storage battery in a vehicle equipped with a secondary storage battery such as a lead storage battery.
[0002]
[Prior art]
It is very useful to be able to detect in advance the remaining capacity and remaining life (or deterioration state) of a secondary storage battery such as a lead storage battery mounted on a vehicle such as a passenger car.
For example, if the remaining life of the in-vehicle secondary storage battery can be detected at an appropriate timing, the secondary storage battery can be replaced at an appropriate timing, and the vehicle can be prevented from becoming inoperable at the end of the secondary storage battery.
In order to reduce environmental pollution and improve vehicle fuel efficiency, the vehicle has an idling stop function that stops the internal combustion engine (engine), such as when the vehicle is temporarily stopped at an intersection to wait for a signal or when it is stopped due to traffic jams. The vehicles that have them are being put into practical use. When performing such an idling stop, it is necessary to know that there is a remaining capacity in the in-vehicle secondary storage battery and / or to know the deterioration state of the secondary storage battery as long as the vehicle can be restarted after the idling stop.
[0003]
As such a secondary storage battery, a storage battery such as a lead storage battery has been frequently used so far. Hereinafter, a conventional method and apparatus for determining the state of a storage battery such as the remaining capacity and / or remaining life (deterioration state) of the storage battery when the storage battery is mounted on a vehicle will be described.
Various methods for measuring the remaining capacity of a storage battery have been tried. Hereinafter, an overview of a conventional method for measuring the remaining capacity of a storage battery will be given.
[0004]
Since lead acid batteries produce water by discharging and produce sulfuric acid by charging, the specific gravity of the sulfuric acid aqueous solution is reduced when discharged, and the specific gravity of the sulfuric acid aqueous solution is restored by charging. Using this phenomenon, a method of estimating the remaining capacity using the specific gravity of the electrolyte as an index is known.
However, since the concentration distribution of the electrolyte contained in the lead storage battery often becomes non-uniform, this method cannot always accurately estimate the remaining capacity of the lead storage battery. In recent years, sealed lead-acid batteries with very little electrolyte have been adopted. For such a sealed lead-acid battery, it is difficult to measure the specific gravity of the electrolyte itself, so the remaining capacity of the lead-acid battery cannot be estimated.
[0005]
Japanese Patent Laid-Open No. 53-127646 discloses a technique for calculating the output impedance of a battery from the relationship between the starter current during starter cranking and the battery terminal voltage, and detecting the state of the battery from this output impedance. .
More specifically, Japanese Patent Laid-Open No. 53-127646 discloses (1) the transient current value of the alternator generated when the engine start key is turned between the alternator and the in-vehicle lead acid battery (battery). And measuring the terminal voltage of the battery, calculating the measurement results with an operational amplifier to obtain the initial remaining capacity of the battery immediately before the vehicle travels, (2) Further, a method is disclosed in which the amount of charge or charge / discharge during vehicle travel is determined, and (3) the remaining capacity of the battery is calculated by comparing the initial remaining capacity and the charge / discharge amount.
However, since the output impedance changes greatly due to the influence of polarization in the battery, the state of the battery cannot be determined using the output impedance that changes greatly. It is sufficient to wait until the output impedance is stabilized. However, in order to wait until the output impedance is stabilized, the vehicle needs to be stopped for several hours or more, which is not practical.
[0006]
Japanese Laid-Open Patent Publication No. 1-129177 discloses an invention obtained by improving the method described in Japanese Laid-Open Patent Publication No. 53-127646. In the method described in Japanese Patent Laid-Open No. 1-129177, focusing on the fact that the output impedance is stabilized when the change in the open circuit voltage (open circuit voltage) of the battery is reduced, the open circuit voltage of the battery when the vehicle is stopped. This is a method of detecting the state of the battery using the output impedance in that state by detecting that the change in the battery has become below a predetermined value.
However, even if only the output impedance calculated in this way is used, the state of the battery cannot be detected sufficiently accurately, and in any case, it is necessary to wait until the polarization of the battery becomes stable. Therefore, a method for detecting the state of the battery in a shorter time is desired.
[0007]
The characteristics of the battery, for example, the open-circuit voltage depends on the temperature of the battery, but the methods disclosed in Japanese Patent Laid-Open Nos. 53-127646 and 1-129177 do not consider temperature dependence. Therefore, there is a limit to accurate battery state detection. Furthermore, the countermeasures such as when the battery is replaced are not considered. In particular, in such a method, it is impossible to determine at which level of the battery life the deterioration state of the battery is.
[0008]
Japanese Patent Laid-Open No. 63-27776 (1) actually measures the terminal voltage drop of the battery relative to the amount of discharge charge during engine start-up in a new battery when the battery is first installed in the vehicle, and (2) The engine starts every time the vehicle travels on condition that the time required for battery static characteristics to recover (stable polarization) has elapsed between engine stop and start, and that the remaining battery capacity is greater than or equal to a predetermined value. Disclosed is a method for measuring the battery terminal voltage drop with respect to the amount of discharge charge in the battery and (3) calculating the battery life by calculating using the initial voltage drop and the voltage drop after running. Yes.
As described above, this method also has to wait until the polarization of the battery is stabilized, and the state of the battery cannot be accurately detected even using only the voltage drop.
[0009]
JP-A-1-39068 (1) detects the discharge current of a battery at a plurality of time points indicating different values during a large current discharge such as when the starter is started, and the terminal voltage of the battery when each discharge current flows out. (2) The internal resistance value and power of the battery are calculated from the detected current and voltage values, and (3) calculated using a function representing the correlation between the battery capacity, the internal resistance and the electromotive force obtained experimentally in advance. Discloses a method for detecting the state of the battery from the internal resistance and the electromotive force.
However, this method cannot accurately detect the state of the battery, and the processing of this method is complicated.
[0010]
Japanese Patent No. 2536257 (Japanese Patent Laid-Open No. 4-95788) discloses an invention that uses an internal impedance to detect the remaining capacity of a lead-acid battery. In the present invention, (1) the internal impedance of the lead storage battery is measured, and (2) the measured internal impedance of the lead storage battery is converted into the inductance component L, electrolyte resistance RΩ, charge transfer resistance Rct, electric double layer capacity of the lead storage battery. Apply an equivalent circuit consisting of Cd, Warburg impedance W, and Warburg coefficient σ to find an optimal solution. (3) Compare at least one of L, RΩ, Rct, Cd, W, and σ with the initial value, The life of the lead storage battery is determined from the difference.
However, in the present invention, it is difficult to measure the internal impedance of the lead storage battery due to the influence of the generator on the lead storage battery and the load fluctuation of the equipment mounted on the automobile. If the internal impedance of the lead-acid battery cannot be measured, it cannot be compared with the initial value and the life cannot be determined. Further, when the present invention is implemented, the configuration of the measuring apparatus is complicated, the size is increased, and the price is increased.
[0011]
There is also known a method in which a current value discharged or charged from a storage battery is constantly measured, and the measured current value is integrated to determine the remaining capacity of the storage battery. Hereinafter, this method is referred to as “current integration method”.
In such a current integration method, the error of the integrated value gradually increases due to the measurement error of the current value, and the state of the storage battery cannot be obtained accurately. For this reason, methods that improve the “current integration method” have been proposed in Japanese Patent No. 2791751 (Japanese Patent Laid-Open No. 8-19103), Japanese Patent Laid-Open No. 9-71065, and the like.
[0012]
The invention described in Japanese Patent No. 2791751 measures the remaining capacity of a lead-acid battery for an electric vehicle by performing data processing using both the current integration method and the internal resistance detection method. That is, (1) First, the remaining capacity of a lead storage battery mounted on an electric vehicle is calculated by a current integration method. (2) Further, when the full charge of the lead storage battery for an electric vehicle is completed and when the vehicle is temporarily stopped The internal impedance of the lead storage battery is measured, and (3) the value of the remaining capacity of the storage battery obtained by the current integration method is corrected by the discharge rate derived from the internal impedance.
This method is useful as a method for inspecting the remaining capacity of a storage battery for automobiles, and is an important technique in an electric vehicle that needs to know the remaining capacity of a lead storage battery accurately.
However, according to the present invention, in addition to the measurement by the current integration method, it is also necessary to perform the measurement by the internal impedance. When a measuring device that realizes this method is manufactured, the device price becomes high. In particular, according to the present invention, it is difficult to measure the internal impedance described above.
[0013]
The invention disclosed in Japanese Patent Laid-Open No. 9-171065 is a technique for calculating a remaining capacity of a storage battery by a current integration method and correcting the remaining capacity. To calculate the corrected remaining capacity, a data table of terminal voltage and remaining capacity in constant current discharge at a specific discharge current value is prepared in advance, and it is detected that the specific discharge current value continues for a certain period of time while the vehicle is running. Then, the terminal voltage of the storage battery at that time is measured, and the remaining capacity of the storage battery for correction is obtained by referring to the measured terminal voltage in the data table.
Then, the remaining capacity of the current integration method obtained in advance is corrected with the calculated remaining capacity for correction.
The invention disclosed in Japanese Patent Laid-Open No. 9-171655 is a technique suitable for measuring the remaining capacity of a storage battery (battery) mounted on an electric vehicle such as an electric vehicle. The reason is that, in an electric vehicle, there are many opportunities to obtain the remaining capacity of the storage battery by setting the discharge current value at the traveling speed that the vehicle normally uses to the above-mentioned specific discharge current value.
However, the invention disclosed in Japanese Patent Application Laid-Open No. 9-171065 is not suitable for the remaining capacity of a storage battery mounted on a vehicle (normal automobile) operating with an internal combustion engine. The reason for this is that in ordinary cars, there are few opportunities for specific current values that frequently continue for a certain period of time while the car is running, so there are very few opportunities to determine the remaining capacity of the storage battery, so the This is because the capacity cannot be obtained.
[0014]
As a method for solving the above-described problem of the invention disclosed in Japanese Patent Laid-Open No. 9-171655, for example, a plurality of terminal voltage and remaining capacity data tables are prepared, and the remaining capacity is determined by a plurality of current values. Is also possible.
However, in order to implement such a method, it is necessary to prepare a plurality of data tables, and the processing becomes complicated. In order to accurately measure the remaining capacity, if the relationship between the terminal voltage of the storage battery and the remaining capacity changes depending on the temperature and the deterioration state, it is necessary to prepare more data tables accordingly. It is assumed that a complicated device is required to store and process the data. In addition, it is troublesome to create such a large amount of data. It is also difficult to judge the deterioration state of the storage battery.
[0015]
[Problems to be solved by the invention]
Various conventional techniques have been discussed above. However, these techniques are particularly problematic when applied to state determination of secondary storage batteries such as storage batteries mounted on vehicles.
[0016]
The objective of this invention is providing the method and apparatus which can estimate the remaining capacity and / or remaining lifetime (future lifetime) of a vehicle-mounted secondary storage battery.
It is another object of the present invention to provide a method and apparatus for determining the remaining capacity and / or remaining life of a secondary storage battery without depending on the type and size of the on-board secondary storage battery.
It is another object of the present invention to provide a method and an apparatus for determining the remaining capacity and / or remaining life of a secondary storage battery that can achieve the above object even if the manufacturer of the on-board secondary storage battery changes.
[0017]
[Means for Solving the Problems]
The basic concept of the present invention will be described.
(1) When a new secondary storage battery is mounted on a vehicle, an internal resistance (initial internal resistance) R0 at that time and a limit internal resistance Re that is a limit of engine start are calculated. The initial internal resistance R0 is calculated from the measurement result of the open circuit voltage E, the measured value of the maximum load current Imax flowing from the secondary storage battery during the engine start period, and the measured value of the maximum load terminal voltage Vmax. The limit internal resistance Re, which is the limit for starting the engine, is obtained from the measured value of the open circuit voltage E, the lower limit voltage Ve, which is the limit for starting the engine, and the maximum load power Wmax required for starting the engine.
(2) Thereafter, each time the engine is started, the internal resistance R of the secondary storage battery is calculated after the start period. The internal resistance R is a measured value of the open circuit voltage E of the secondary storage battery before the engine starting period, a measured value of the maximum load current I flowing from the secondary storage battery during the engine starting period, and a measured value of the secondary storage battery during the engine starting period. It is calculated from the measured value of the terminal voltage V. The internal resistance R is calculated every time the engine is started.
Note that the calculation of the initial internal resistance R0 and the calculation of the limit internal resistance Re described above preferably uses the open circuit voltage E before the engine start period. Or after using a secondary storage battery, you may carry out using the open circuit voltage E after a fixed period passes and the state of a secondary storage battery is stabilized. The internal resistance R is preferably calculated by using an open circuit voltage E after a certain time has elapsed and the state of the secondary storage battery has stabilized, and an open circuit before the engine start-up period that is performed after the certain time has elapsed. The voltage E may be used. In the above-described calculation, it is desirable to correct the temperature according to the temperature of the secondary storage battery.
(3) When the internal resistance R is calculated every time the engine is started, the remaining life SOH is calculated using the initial internal resistance R0, the limit internal resistance Re, and at least one internal resistance R.
The internal resistance and the remaining life SOH have a relationship as exemplified by the solid curve CV1 in FIG. 10, for example, the remaining life SOH = 0% when the limit internal resistance Re is the limit of engine start, and the initial internal resistance If the remaining life SOH at the time of R0 is 100%, the remaining life SOH can be estimated from the value of the internal resistance R.
[0018]
In this way, the internal resistance R0 of the secondary storage battery in the initial state when the secondary storage battery is replaced and the limit internal resistance Re that becomes the limit of engine start are calculated, and then the secondary storage battery of each time the engine is started. The internal resistance R is calculated, and the remaining life SOH can be accurately calculated using these data.
[0019]
According to the first aspect of the present invention, (a) the first time when the secondary storage battery is mounted on the vehicle, the open circuit voltage of the secondary storage battery before the engine start period, the current flowing through the secondary storage battery during the engine start period, The voltage between terminals is measured, and using these measured values, the initial internal resistance R0 and the limit internal resistance Re that is the limit of engine start are calculated. (B) After the second time when the secondary storage battery is mounted on the vehicle, Every time the engine is started, the open circuit voltage of the secondary storage battery before the engine start period, the current flowing through the secondary storage battery during the engine start period, the voltage between the terminals are measured, and the internal resistance R is calculated using these measured values. (C) calculating a remaining life (SOH) from the initial internal resistance R0, the limit internal resistance Re, and at least one internal resistance R;Process,A method for determining a state of a secondary storage battery mounted on a vehicle is provided.
[0020]
Specifically, the initial internal resistance R0 is calculated by the following formula A, the limit internal resistance Re that is the limit of the engine start is calculated by the following formula B, the internal resistance R is calculated by the following formula C, SOH is calculated by the following formula D.

SOH (%) = [(Re-R) / (Re-R0)] × 100 (D)
[0021]
    R0 = (E2-V_max) / I_max
          Where E2 is an open circuit voltage,
                  V_maxIs the maximum load terminal voltage,
                  I_maxIs the maximum load current.
                                                          ... (A)
    Re = ((E2−Ve) × Ve) / W_max
          Where E2 is an open circuit voltage,
                  Ve is the lower limit voltage that becomes the engine start limit,
                  W_maxIs the maximum load power required to start the engine.
                                                          ... (B)
    R = (E2-V₂) / I
          Where E2 is an open circuit voltage,
                  V₂Is the maximum load end after the second time when the secondary storage battery is mounted on the vehicle
                  The voltage between the children
                  I is the maximum load current after the second time when the secondary storage battery is mounted on the vehicle
                  It is.
                                                          ... (C)
    SOH (%) = [(Re-R) / (Re-R0)] × 100
                                                          ... (D)
[0022]
  Preferably, the temperature of the secondary storage battery is measured, and the open circuit voltage and the inter-terminal voltage are corrected at the measured temperature.
[0023]
More preferably, the current internal resistance is calculated by calculating an approximate expression using the calculated plurality of internal resistances as a variable of the engine start frequency, and the current internal resistance, the initial internal resistance R0, and the limit internal resistance Re To calculate the SOH.
[0024]
Preferably, SOH when the internal resistance of the secondary storage battery is the value of the initial internal resistance is 100%, SOH when the internal resistance of the secondary storage battery is the value of the limit internal resistance Re is 0%, SOH corresponding to the internal resistance is expressed in%.
[0025]
Preferably, the process is performed after a period during which the state of the secondary storage battery is stabilized after use of the secondary storage battery.
[0026]
Preferably, the secondary storage battery is a lead storage battery.
[0027]
According to a second aspect of the present invention, there is provided an apparatus comprising means for performing the above method.
[0028]
According to the third aspect of the present invention, a voltmeter for measuring a voltage of a secondary storage battery mounted on a vehicle, an ammeter for detecting a current flowing through the secondary storage battery, and a signal indicating engine start-up And an engine start signal generating means for generating
[0029]
DETAILED DESCRIPTION OF THE INVENTION
First embodiment
As a first embodiment of the present invention, a secondary storage battery mounted on a vehicle having a so-called idling stop function for stopping an internal combustion engine (engine) while the vehicle is running is temporarily stopped due to a traffic jam or an intersection. A method and apparatus for determining the remaining capacity and the deterioration state, and a method and apparatus for performing an idling stop process based on the determination result of the remaining capacity and the deterioration state of the secondary storage battery will be described.
[0030]
FIG. 1 is a configuration diagram of an apparatus for determining the remaining capacity and / or deterioration state of the secondary storage battery according to the first embodiment of the present invention (hereinafter referred to as remaining capacity / deterioration state determination apparatus).
A vehicle, for example, an ordinary passenger car, is equipped with a starter 1, a generator (alternator) 2, a secondary storage battery 3, electrical equipment 4, and an engine 5 connected via a bus 9.
Hereinafter, a case where a lead storage battery is used as the secondary storage battery 3 will be described.
The electric equipment 4 is a general term for things mounted on a vehicle that operates by electricity such as various lights (lamps) such as an illumination lamp, a direction indicator lamp, a hazard lamp, a mirror drive motor, an operation panel, and an air conditioner.
[0031]
1 is a temperature sensor 6 that measures the temperature of the lead storage battery 3, a voltmeter 7 that measures the terminal voltage of the lead storage battery 3, and a current that flows through the secondary storage battery 3. An ammeter 8 for calculating the remaining capacity / deterioration state of the lead storage battery 3, and a display means 16 for displaying the result of the calculating means 10.
The remaining capacity / deterioration state determination device illustrated in FIG. 1 can include a control unit 12 that performs a vehicle drive control process according to the result of the calculation unit 10.
[0032]
Furthermore, an idling stop (IS) processing unit 14 that performs an idling stop (IS) process according to the result of the calculation unit 10 can be included. In this case, the remaining capacity / deterioration state determination device has an idling stop processing function. This is a device for determining the remaining capacity and / or deterioration state of the secondary storage battery.
[0033]
The starter 1 provides electric power for operating the engine 5 by power supply from the lead storage battery 3 when the vehicle is started. The alternator 2 is activated to generate electric power when the vehicle is started and the engine 5 is rotated. In addition to supplying power to the electric equipment 4 by the power generation of the alternator 2, the lead storage battery 3 is charged.
[0034]
As the engine start signal generation means of the present invention, for example, a starter start switch signal SW1, an alternator start switch signal SW2, and an engine start switch signal SW5 are input to the calculation means 10. Although all of these switch signals are not necessary, a signal indicating the start of the engine is input to the arithmetic means 10.
[0035]
The temperature sensor 6 measures the temperature of the lead storage battery 3 and uses the temperature measured by the temperature sensor 6 for correcting the voltage between the terminals of the lead storage battery 3 as will be described later.
The measurement site of the temperature sensor 6 depends on the reference temperature for temperature correction. To be precise, it is desirable to measure the temperature of the electrolytic solution with the temperature sensor 6 using the temperature of the electrolytic solution of the lead storage battery 3 as a reference temperature. When the reference temperature is the outer wall of the lead storage battery 3, the outer wall of the lead storage battery 3 is measured by the temperature sensor 6. When the reference temperature is in the vehicle in which the lead storage battery 3 is installed, the temperature sensor 6 measures the temperature in the vehicle in which the lead storage battery 3 is installed.
Moreover, when the reference temperature is the temperature of the electrolyte solution of the lead storage battery 3, for example, the temperature of the outer wall of the lead storage battery 3 is measured by the temperature sensor 6, and the temperature of the electrolyte solution is estimated from the measured temperature in the arithmetic means 10. You can also.
The measurement site of the temperature sensor 6 thus depends on the reference temperature, but hereinafter, the temperature of the lead storage battery 3 is measured by the temperature sensor 6 in a broad sense, regardless of the temperature measurement site of the temperature sensor 6.
Although the temperature sensor 6 depends on the measurement site, the temperature range of the lead storage battery 3 is about −30 to 100 ° C., so it is suitable for such temperature measurement, does not take up an occupied place, and is handled at a low price. For example, a copper / constantan thermocouple or a platinum resistor can be used. The lead storage battery 3 may have a built-in temperature sensor 6, in which case the temperature sensor can be used.
[0036]
The voltmeter 7 measures the voltage between the terminals of the lead storage battery 3 or the open voltage, and a normal DC voltmeter can be used. The measurement range by the voltmeter 7 is, for example, 0 to 50 VDC.
The inter-terminal voltage of the lead storage battery 3 refers to a voltage between a low potential level of the lead storage battery 3, for example, a ground voltage and a high potential level, for example, a potential on the electric equipment 4 side of the lead storage battery 3. The voltage between the terminals is measured with a voltmeter 7.
[0037]
The display means 16 is a device that displays the result of the calculation means 10 on a vehicle driver or the like, and is, for example, a liquid crystal display provided on a dashboard portion of the vehicle, and a display on an operation panel portion of a normal passenger car. It can also be used.
[0038]
FIG. 2 is a diagram showing a specific configuration example of the calculation means 10 illustrated in FIG.
The arithmetic means 10 includes a central processing unit (CPU) 100 of a microcomputer, a ROM 102 in which various programs and various parameters operating on the CPU 100 are stored, a result of intermediate processing performed by the CPU 100, and various parameters. RAM 104 used for storage, A / D converter (A / DC) 106 for inputting detection signals of temperature sensor 6, voltmeter 7 and ammeter 8 inputted as analog signals and converting them into digital signals, and digital A digital input unit (DI unit) 108 for inputting a starter start switch signal SW1, an alternator start switch signal SW2 and an engine start switch signal SW5 inputted as signals, a control means 12 and an idling stop (IS) processing means for the result of the CPU 100 Output to 14 A communication interface (I / F) 112 for inputting a signal from the control unit 12 and IS processing unit 14, and a display interface (DSPI / F) 114 for outputting display information to the display unit 16 from the CPU 100.
[0039]
The input voltage range of the A / D converter (A / DC) 106 is, for example, about 0 to 5V.
When the detection voltage is very low, for example, about 0 to 20 mV, as in the case where a thermocouple is used as the temperature sensor 6, it is amplified to 0 to 5 V by the circuit in the previous stage of the A / DC 106.
For example, when the detected current of the ammeter 8 is output as a signal of about 0 to 1 V, it is amplified to 0 to 5 V by the circuit in the previous stage of the A / DC 106.
Similarly, when the detection voltage of the voltmeter 7 is as low as about 0 to 1 V, for example, it is amplified to 0 to 5 V by the circuit in the previous stage of the A / DC 106.
[0040]
FIG. 3 is a flowchart illustrating the processing performed by the arithmetic means 10 illustrated in FIGS. 1 and 2, particularly the CPU 100.
Hereinafter, the operation of the computing means 10 will be described. More specifically, the CPU 100 performs the processing described below according to various programs stored in the ROM 102.
[0041]
  Step 1: Determining whether or not deterioration determination processing is possible
  The calculation means 10 (CPU 100) checks whether or not the first predetermined time t61 has elapsed after the lead storage battery 3 has been used last time.
  Lead storage battery 3 has a first predetermined time t₁The CPU 100 drives the timer 110 after using the lead storage battery 3 to read the time measured by the timer 110 periodically every second, for example, and stores it in the RAM 104. The time measured by the timer 110 after reading the information is a first predetermined time t.₁Check whether or not.
  The CPU 100 performs the first predetermined time t after the use of the lead storage battery 3.₁BeforeVia step 2After proceeding to the processing of step 12 and using the lead storage battery 3, the first predetermined time t₁After the elapse of time, the deterioration determination process after step 3 is performed.
[0042]
  Step 2,After the use of the lead storage battery 3, the first predetermined time t₁When has not elapsed, the CPU 100 does not perform the deterioration determination process of the lead storage battery 3 and proceeds to the process of step 12. In this case, in step 12 to be described later, the calculation was performed in the previous step 11., The internal resistance of the lead storage battery 3, that is, the output internal resistance value,The R value is used.
[0043]
Meaning of waiting for a predetermined time
After the use of the lead storage battery 3, the first predetermined time t₁ The reason why the deterioration determination process of the lead storage battery 3 is not performed before the passage will be described.
FIG. 4 is a graph showing a state in which the open circuit voltage of the lead storage battery is stabilized.
As illustrated in FIG. 4, after the lead storage battery having the same degree of deterioration is adjusted to the same SOC (charge capacity) by charging and discharging, the first predetermined time t is required for the open circuit voltage E1 to stabilize.₁ Since it is necessary to wait until only a lapse of time, the first predetermined time t that is stable in order to measure a more accurate open circuit voltage E1.₁ Only need to wait.
First predetermined time t₁ As illustrated in FIG. 4, this is a time sufficient for the open circuit voltage E1 to stabilize, for example, several hours.
[0044]
  Step 3: Open circuit voltage measurement and temperature correction
  The CPU 100 inputs the measured value of the voltmeter 7 and the detected value of the temperature sensor 6 via the A / DC 106. The measured value of the voltmeter 7 indicates the open circuit voltage E1 of the lead storage battery 3.
  The open circuit voltage (open voltage) E1 is the bus 9 when the vehicle is stopped and all loads of the electrical equipment 4 are turned off.Of the secondary storage battery 3 connected toVoltage.
[0045]
The open circuit voltage E1 has temperature dependency as illustrated in FIG. FIG. 5 is a graph showing a temperature / open circuit voltage characteristic curve.
Therefore, the CPU 100 corrects the temperature of the open circuit voltage E1 based on the detection result of the temperature sensor 6. Note that this temperature correction is not essential because it is a process for accurately obtaining the open circuit voltage E1 depending on the temperature, but it is desirable to perform temperature correction of the open circuit voltage E1.
[0046]
  A specific method of temperature correction will be described.
  (1)The lead-acid battery 3 actually mounted on the vehicle or a typical lead-acid battery 3 is measured in advance by measuring the open circuit voltage E1 for various temperatures, and the temperature / open-circuit voltage characteristic curve of FIG. Ask.
  (2)Next, when the reference temperature, for example, the temperature correction coefficient α16T of the open circuit voltage E1 of 25 ° C. is set to 1.0 and the value based on the curve of FIG. 5 is plotted, the detected value of the temperature sensor 6 is equal to or higher than the reference temperature. Is 1.0Less thanTemperature correction coefficient α1_TWhen the detected value of the temperature sensor 6 is below the reference temperature, a temperature correction coefficient α1 of 1.0 or more_TOpen circuit voltage and temperature correction coefficient α1_TFind the curve.
  (3)Next, the open circuit voltage E1 measured by the voltmeter 7 is corrected based on the following formula 1.
[0047]

[0048]
The temperature correction coefficient α1_T Can be considered to show a substantially constant slope from the characteristics of FIG._T = A (constant value) or a more accurate temperature correction coefficient α1_T Can be calculated and used.
More accurate temperature correction coefficient α1_T The calculation method of is described. The measured temperature / open circuit voltage characteristic curve is tabulated based on the measured temperature and the measured open circuit voltage, and the temperature correction coefficient α1 is stored in the ROM 102 or RAM 104._T The value of is memorized. The CPU 100 sets the temperature correction coefficient α1 tabulated in the ROM 102 or RAM 104._T Are read out using the temperature detected by the temperature sensor 6 as a variable. If the temperature detected by the temperature sensor 6 is other than the temperature plotted in advance, the temperature correction coefficient α1 of the temperature used for the plots on both sides thereof is used._T The temperature correction coefficient α1 corresponding to the detected temperature is interpolated with reference to FIG._T Ask for.
[0049]
  The temperature-corrected open circuit voltage E2 varies depending on the SOC state. An example is shown in FIG. FIG. 6 is a graph showing an SOC (%) / open circuit voltage characteristic curve in which the horizontal axis represents SOC /% and the vertical axis represents temperature corrected open circuit voltage E2 at a reference temperature of 25 °, for example.
  SOC (%) and open circuit voltage characteristic curve illustrated in Fig. 6To sayIn the case of lead acid battery 3, the open circuit voltage is proportional to the specific gravity of the sulfuric acid that constitutes the electrolyte.What changesThis is because the specific gravity of sulfuric acid constituting the electrolytic solution is changed by charging and discharging.
[0050]
Step 4: Detection of engine start
The CPU 100 detects that the engine 5 is started. For detection of the start of the engine 5, for example, the starter start switch signal SW1 indicating the start of the starter 1 or the engine start switch signal SW5 indicating the start of the engine 5 is input via the digital input unit (DI unit) 108. It can be detected with time.
[0051]
Step 5: Maximum load current at engine start, maximum load terminal voltage, lead storage battery temperature measurement, and maximum load terminal voltage temperature correction
When the start of the engine 5 is detected, the CPU 100 detects the maximum load current I when the engine 5 is started._max Maximum load terminal voltage V_max1And the temperature of the lead storage battery 3 at that time is detected. Maximum load current I_max Indicates the detected value of the ammeter 8 as the maximum load terminal voltage V_max1The temperature of the lead storage battery 3 is obtained by inputting the detected value of the temperature sensor 6 via the A / DC 106.
[0052]
As illustrated in FIG. 7, when the engine 5 is started, it means a period in which a large current flows for a short time from the lead storage battery 3 as the engine 5 starts, for example, a period of several seconds. More precisely, the lead storage battery 3 is a period from when the negative current starts flowing until the alternator 2 operates and a positive current flows.
FIG. 7 is a graph showing a time / current change characteristic indicating a change in current with the passage of time when the engine is started.
[0053]
FIG. 8 is a characteristic diagram showing the relationship between the engine start time and the internal resistance of the lead storage battery 3. Although the starting time of the engine 5 has a certain degree of correlation with the internal resistance of the lead storage battery 3, only the engine starting time increases as the deterioration progresses. If the lead storage battery 3 is extremely deteriorated, the engine starting time becomes very long because the current at the time of starting the engine cannot sufficiently flow. Further, since the magnitude of the current is small and the voltage between terminals does not decrease so much, a phenomenon occurs in which the internal resistance at the maximum load does not increase.
[0054]
  Maximum load terminal voltage V _max1 Temperature compensation
  The CPU 100 preferably uses the detected temperature of the lead storage battery 3 to measure the maximum load terminal voltage V measured by the voltmeter 7._max1Perform the temperature correction.
  FIG. 9 shows the temperature change of the lead storage battery 3 on the horizontal axis, and the maximum load terminal voltage V₁It is a graph which shows the temperature change and the voltage characteristic between maximum load terminals which took the measured value of this for the vertical axis | shaft.
  Maximum load terminal voltage V_max1The necessity of temperature correction will be described. For example, when the maximum load terminal voltage of the lead storage battery 3 is measured at a low temperature in a cold region, the maximum terminal voltage of the lead storage battery 3 detected at the start of the starter 1 is normal temperature.timeFor example, it becomes lower than the measured value of the maximum terminal voltage at 25 ° C. Therefore, for example, when the internal resistance of the lead storage battery 3 to be described later is calculated by using the maximum inter-terminal voltage without correcting the temperature of the maximum inter-terminal voltage with the normal temperature as the reference temperature,The internal resistance of the lead storage battery 3 at that time isIt becomes larger than the internal resistance at room temperature, and an accurate internal resistance is not required. As a result, the deterioration determination of the lead storage battery 3 cannot be performed accurately. Therefore, in the CPU 100, the maximum load terminal voltage V_max1Perform the temperature correction.
[0055]
When the vehicle is always used at room temperature, the voltage between the terminals of the lead storage battery 3 described above, particularly when the voltage between the terminals at the maximum load does not show the above-described change, the maximum load described below will be described. There is no need to correct the temperature of the voltage across the terminals.
[0056]
  The maximum load terminal voltage V_max1The temperature correction processing will be described.
  Also in this case, the open circuit voltage / temperature correction coefficient α1 at the detected temperature described with reference to FIG._TThus, the same processing as that in which the temperature of the open circuit voltage E1 is corrected is performed.
  (1) First, the maximum load terminal voltage V at several temperatures₁And a characteristic curve illustrated in FIG. 9 is obtained in advance.
  (2) Next, a reference temperature, for example, a maximum load terminal voltage V of 25 ° C.₁Temperature correction coefficient α2_TIs 1.0, and a value based on the curve of FIG. 9 is plotted. When the detected value of the temperature sensor 6 is equal to or higher than the reference temperature, 1.0 is set.More thanTemperature correction coefficient α2_TWhen the detected value of the temperature sensor 6 is below the reference temperature, 1.0Less thanTemperature correction coefficient α2_TA curve with the detected temperature as a variable is obtained.
  (3) Furthermore, the temperature correction coefficient α2 of the temperature-maximum load terminal voltage_TIs converted into a table and the maximum load terminal voltage temperature correction coefficient α2 is stored in the ROM 102 or the RAM 104._TThe value of is memorized.
  (4)The CPU 100 sets the maximum load terminal voltage temperature correction coefficient α2 in the form of a table in the ROM 102 or RAM 104._TAre read out using the temperature detected by the temperature sensor 6 as a variable. When the temperature detected by the temperature sensor 6 is other than the temperature plotted in advance, the temperature correction coefficient α2 of the temperature used for the plots on both sides thereof is used._TThe temperature correction coefficient α2 corresponding to the detected temperature by interpolation with reference to_TAsk for.
  (5)Maximum load terminal voltage V measured with voltmeter 7 using equation 2 below_max1Is corrected by the temperature of the lead storage battery 3 detected by the temperature sensor 6 at that time.
[0057]

[0058]
  Step 6: Determination of whether or not the lead storage battery 3 is new
  When a new lead acid battery 3 is replaced,VehicleA flag indicating that a mechanic or the like has replaced the lead storage battery 3 in the RAM 104 is set as flag = 0.
  The CPU 100 reads the flag, and when the flag = 0, it detects that the new lead storage battery 3 has been replaced. In that case, the CPU 100 proceeds to the processing of steps 7 and 8.
  When the flag of the RAM 104 is not 0, that is, when the flag = 1, the CPU 100 proceeds to the process of step 9.
[0059]
Steps 7 and 8: Calculate and store the internal resistance of a new lead-acid battery
The CPU 100 sets the flag = 1 so that the new lead storage battery 3 is not processed from the next time.
The CPU 100 calculates the internal resistance of the new lead-acid battery 3, that is, the initial internal resistance R0 based on the following formula 3, and further calculates the limit internal resistance Re that becomes the limit of engine start based on the following formula 4. .
[0060]

[0061]

[0062]
Maximum load power W required to start the engine of the lead-acid battery installed in the vehicle_max Is almost constant for the same vehicle, and the maximum load power W measured in advance_max Are commonly used for vehicles of the same model. This maximum load power W_max Is stored in the ROM 102 or the RAM 104.
[0063]
Step 8: Maintain initial internal resistance R0 and limit internal resistance Re
The CPU 100 stores the calculated internal resistance of the new lead-acid battery 3, that is, the initial internal resistance R 0 and the limit internal resistance Re that is the limit for starting the engine in the RAM 104 and saves them. Thereafter, the CPU 100 proceeds to the process of step 12.
[0064]
  Step 9: Determination of engine start time change
  The CPU 100 checks whether the engine start time Δt detected by the ammeter 8 is a certain value, for example, 2 seconds or more. Although the engine start time Δt shown in FIG. 7 has a certain degree of correlation with the internal resistance of the lead storage battery 3, only the engine start time Δt increases as the deterioration progresses. If the lead storage battery 3 is extremely deteriorated, the engine start time Δt becomes very long because the current at the time of engine start cannot be sufficiently supplied. Further, since the magnitude of the current is small and the voltage between terminals does not decrease so much, a phenomenon occurs in which the internal resistance at the maximum load does not increase.
  FIG. 8 is a characteristic diagram showing the relationship between the engine start time and the internal resistance of the lead storage battery 3.
  Therefore, the internal resistance and start time at the start of the engine are measured, and usually the deterioration is determined using the internal resistance. If the engine start time Δt is greater than a certain value, the SOHTheJudged to be 0%. If the engine start time Δt is greater than or equal to a certain value, the CPU 100 proceeds to the process of step 10. When the engine start time Δt is equal to or less than a certain value, the CPU 100 proceeds to the process of step 11.
[0065]
Step 10: Output with no remaining life
The CPU 100 determines that there is no remaining life of the lead storage battery 3 and outputs this information to the control means 12, IS processing means 14, and display means 16 with SOH = 0% and remaining life = 0.
For example, “SOH = 0%, remaining life = 0” is displayed on the display means 16 as a message.
In the present embodiment, as illustrated in FIG. 10, when the internal resistance of the lead storage battery 3 is the limit internal resistance Re at which the engine start is limited, SOH = 0%, and the internal resistance of the lead storage battery 3 is At the initial internal resistance R0, SOH = 100%. Thus, since SOH can be expressed as 0 to 100%, the state of the lead storage battery 3 is very easy to understand for the user.
[0066]
Step 11: When the secondary storage battery is mounted on the vehicle, the maximum load current, the maximum load terminal voltage, the temperature measurement, the temperature correction of the maximum load terminal voltage, and the internal resistance calculation
The CPU 100 is the same as the process in step 5, except that the maximum load current I and the maximum load terminal voltage V after the second time when the secondary storage battery is mounted on the vehicle, not at the start of the engine this time.₁ And the temperature of the lead storage battery 3 at that time is detected. The maximum load current I is the detected value of the ammeter 8 and the maximum load terminal voltage V₁ Is obtained by inputting the measured value of the voltmeter 7 and the temperature of the lead storage battery 3 by inputting the detected value of the temperature sensor 6 through the A / DC 106.
Next, the CPU 100 preferably uses the detected temperature of the lead storage battery 3 to measure the maximum load terminal voltage V measured by the voltmeter 7.₁ Is corrected according to the equation 5 described with reference to FIG. The temperature correction coefficient α2 described with reference to FIG._T Is also used for this temperature correction.
[0067]

[0068]
Calculation of internal resistance of lead acid battery
The CPU 100 calculates the internal resistance of the lead storage battery 3, that is, the output internal resistance R based on the following formula 6.
[0069]

[0070]
Step 12: Calculation of SOH
The CPU 100 calculates the initial internal resistance R0 immediately after replacing the lead storage battery 3 calculated by applying Formula 3, the internal resistance R of the lead storage battery 3 calculated by applying Formula 6, and the calculated engine start by applying Formula 3. An index SOH indicating the deterioration state of the lead storage battery 3 is calculated from the limit internal resistance Re which is the limit of
[0071]
SOH (%) = [(Re-R) / (Re-R0)] × 100 (7)
[0072]
Thereafter, the CPU 100 outputs the calculated SOH (%) to the control means 12 and the display means 16.
The control means 12 displays an indicator SOH (%) indicating the deterioration state as a message.
[0073]
Step 13: Repeated calculation of internal resistance
When the engine 5 is started, the CPU 100 performs the processing in step 11, that is, (1) the open circuit voltage before the engine starting period after the second time when the lead storage battery 3 is mounted on the vehicle, and the maximum load current during the engine starting period. Measure the maximum load terminal voltage and temperature, and (2) perform temperature correction of the maximum load terminal voltage, and (3) use these results to calculate the internal resistance as described above. . Further, the CPU 100 stores the calculated internal resistance R in the RAM 104 together with the number of processing times.
[0074]
Step 14: Life prediction
FIG. 10 is a graph illustrating the relationship between the engine start frequency and the output internal resistance, and the relationship between the output internal resistance and SOH.
A curve CV1 indicated by a solid line is obtained by plotting, in the CPU 100, the internal resistance R calculated each time the engine 5 is started a plurality of times calculated in step 13.
A curve CV2 indicated by a broken line is a plot of the internal resistance R calculated for a typical lead acid battery in advance. The value of the curve CV2 is stored in the ROM 102 or the RAM 104. Usually, it is stored in the ROM 102 so that correction can be easily performed.
[0075]
  From the characteristics shown in Fig. 10, SOH is calculated from the output internal resistance.TheIt can be estimated. Therefore, the CPU 100 calculates the internal resistance of the lead-acid battery 3 in accordance with the start of the engine 5 by the above-described method, and measures the plurality of internal resistances stored in the RAM 104, that is, the start count of the engine 5.Plot each internal resistance plotted,For example, a quadratic polynomial approximationFrom quadratic polynomial approximationCalculate the current internal resistance. Next, the CPU 100From the approximationThe calculated internal resistance, the limit internal resistance Re and the initial internal resistance R0, which are the engine start limits calculated in step 7 and stored in the RAM 104, are substituted into Equation 7, and the index SOH indicating the deterioration state is calculated. .
[0076]
Further, the CPU 100 outputs an index SOH indicating the calculated deterioration state to the control means 12, the IS processing means 14, and the display means 16.
The display means 16 displays an indicator SOH indicating the deterioration state, for example, as a message.
[0077]
  The control means 12 refers to the index SOH indicating the deterioration state output from the CPU 100 (calculation means 10), and operates and maintains the vehicle.Etc.It can be reflected.
  For example,VehicleWhen the driver or the mechanic wants to know the index SOH indicating the current deterioration state of the lead storage battery 3, the index indicating the deterioration state stored in the control means 12 by accessing the control means 12 via the operation unit (not shown). For example, the SOH can be confirmed by displaying the SOH on the display unit 16 or the display unit of the operation panel of the vehicle via the control unit 12. As a result, the lead storage battery 3 can be replaced at an appropriate timing.
  Alternatively, when any failure occurs in the vehicle, the control unit 12 checks the index SOH indicating the deterioration state calculated by the calculation unit 10 and determines whether or not the cause of the failure is due to the low SOH of the lead storage battery 3. Can be diagnosed.
[0078]
The idling stop (IS) processing unit 14 can also determine whether or not idling can be stopped with reference to the index SOH indicating the deterioration state calculated by the calculation unit 10.
[0079]
  The display on the display means 16 is not limited to the display of the indicator SOH indicating the deterioration state, and various displays can be performed. For example, at the time of maintenance inspection, etc.Processing stateIntermediate results, for example, the temperature of the lead-acid battery 3, the open circuit voltage E1, the maximum load voltage, the maximum load current, the internal resistance value, the limit internal resistance Re that becomes the limit for starting the engine, and the index SOH indicating the intermediate deterioration state Etc. can be displayed on the display means 16.
[0080]
As described above, according to the first embodiment of the present invention, as illustrated in FIG. 1, the temperature sensor 6, the voltmeter 7, and the ammeter 8 are provided, and the calculation means 10 performs the above-described processing. The index SOH indicating the deterioration state of the lead storage battery 3 can be calculated.
That is, in the present embodiment, the initial internal resistance R0 of the lead storage battery 3 and the limit internal resistance Re that is the limit for starting the engine are calculated from when the new lead storage battery 3 is mounted on the vehicle. Then, every time the engine is started, the current internal resistance of the lead storage battery 3 is calculated. When the internal resistance of the lead storage battery 3 is the initial internal resistance R0, SOH is 100%, and the internal resistance of the lead storage battery 3 is the limit internal resistance. Since the remaining life SOH is set to 0% at the time of Re and the value of the SOH is determined by the current internal resistance according to Equation 7, the SOH can be accurately obtained.
[0081]
In particular, in the present embodiment, since the processing is performed after the operation state of the lead storage battery 3 is stabilized, SOH can be accurately obtained.
[0082]
  Furthermore, in the present embodiment, the lead storage battery 3Measure the temperature and at the measured temperatureSince the voltage of the lead storage battery 3 is corrected, more accurate SOH can be calculated.
[0083]
  Further, in the present embodiment, the internal resistance is calculated every time the engine is started, and as illustrated in FIG.And plot them,For example, polynomial approximationSince it is used, SOH can be calculated more accurately.
[0084]
In the present embodiment, every time the lead storage battery 3 is replaced, the initial internal resistance R0 and the limit internal resistance Re are obtained, so there is no problem even if the lead storage battery 3 is replaced.
In the present embodiment, if only the lower limit voltage Ve used in Expression 4 and the maximum load power Wmax required for starting the lead storage battery 3 are set, the SOH can be calculated regardless of the manufacturer and type of the secondary storage battery.
[0085]
As described above, according to the present embodiment, SOH can always be calculated. Therefore, the remaining life of the lead storage battery 3 can be predicted, and the lead storage battery 3 can be replaced at an appropriate timing.
Also, the idling stop process can be performed using the calculated SOH.
[0086]
It should be noted that when implementing this embodiment, no specially complicated components are required and signal processing is not complicated, so that it can be put into practical use easily and at low cost.
[0087]
In the above embodiment, the case where a lead storage battery is used as the secondary storage battery 3 has been described. However, the present invention is not limited to the lead storage battery, and can be applied to various rechargeable secondary storage batteries. .
[0088]
The embodiment described above is an exemplification, and the application of the present invention is not limited to the embodiment described with reference to the drawings and the above description, and those skilled in the art based on the contents described in the specification and the drawings. Anything that can be recalled should be considered as belonging to the present invention.
[0089]
According to the present invention, the remaining life SOH of the secondary storage battery can be calculated with a simple method and a simple configuration. Furthermore, in the present invention, SOH can be expressed as 0 to 100%, so that it is very easy for the user to understand.
[0090]
The method and apparatus of the present invention can calculate the SOH of the secondary storage battery even when the secondary storage battery is replaced.
[0091]
The method and apparatus of the present invention can calculate the SOH of a secondary storage battery without depending on the type, manufacturer, and characteristics of the secondary storage battery.
[Brief description of the drawings]
FIG. 1 is an apparatus configuration diagram for determining a remaining capacity and / or a deterioration state of a secondary storage battery according to a first embodiment of the present invention.
FIG. 2 is a diagram illustrating a specific example of the device configuration of the arithmetic means illustrated in FIG. 1;
FIG. 3 is a flowchart showing the operation of the apparatus for determining the remaining capacity and / or deterioration state of the secondary storage battery illustrated in FIGS. 1 and 2;
FIG. 4 is a graph showing a state in which the open circuit voltage of the lead storage battery is stabilized.
FIG. 5 is a graph showing a temperature / open circuit voltage characteristic curve;
FIG. 6 is a graph showing an SOC /% / temperature-corrected open circuit voltage characteristic curve in which the horizontal axis is SOC /% and the temperature-corrected open circuit voltage is the vertical axis when the reference temperature is 25 °, for example. It is.
FIG. 7 is a graph showing a time / current change characteristic indicating a change in current with time when the engine is started.
FIG. 8 is a characteristic diagram showing the relationship between the engine start time and the internal resistance of the lead-acid battery.
FIG. 9 is a graph showing the temperature change of a lead storage battery on the horizontal axis, and the maximum load terminal voltage V₁ It is a graph which shows the temperature change and the voltage characteristic between maximum load terminals which took the measured value of this for the vertical axis | shaft.
FIG. 10 is a graph illustrating the relationship between the number of engine starts and the output internal resistance, and the relationship between the output internal resistance and SOH.
[Explanation of symbols]
1. Starter, SW1 Starter start switch signal
2. ・ Alternator, SW2 ・・ Alternator start switch signal
3 .... Secondary storage battery (lead storage battery) 4 .... Electric equipment
5 ・・ Engine, SW5 ・・ Engine start switch signal
6 .... Temperature sensor, 7 .... Voltmeter, 8 .... Ammeter, 9 .... Bus
10. ・ Calculation means
100 ... CPU, 102 ... ROM, 104 ... RAM
106 .. A / D converter (A / DC)
108-Digital input (DI), 110-Timer
112 .. Communication interface (I / F) 112
114 .. Display interface (DSPI / F) 114
12..Control means
14. ・ Idling stop (IS) processing means
16. Display means

Claims

Only when the secondary storage battery is installed in the vehicle, the open circuit voltage of the secondary storage battery before the engine start period, the current flowing through the secondary storage battery during the engine start period, and the voltage between terminals are measured, and these measured values are used. Calculate the initial internal resistance and the limiting internal resistance that is the limit of engine start,
After the second time when the secondary storage battery is mounted on the vehicle, every time the engine is started, the open circuit voltage of the secondary storage battery before the engine start period, the current flowing through the secondary storage battery during the engine start period, and the voltage between terminals are measured. Use these measurements to calculate the internal resistance,
Calculating a remaining life (SOH) of the secondary storage battery from the initial internal resistance, the limit internal resistance, and at least one internal resistance;
A method of determining the state of a secondary storage battery mounted on a vehicle by performing the above process .

The initial internal resistance is calculated by the following formula A,
The limit internal resistance is calculated by the following formula B,
The internal resistance is calculated by the following formula C,
The SOH is calculated by the following formula _{D R0 = (E2-V max} ) / I max
Where E2 is an open circuit voltage,
V _max is the maximum load terminal voltage,
I _max is the maximum load current.
... (A)
Re = ((E2−Ve) × Ve) / W _max
Where E2 is an open circuit voltage,
Ve is the lower limit voltage that becomes the engine start limit,
W _max is the maximum load power required to start the engine.
... (B)
R = (E2-V ₂ ) / I
Where E2 is an open circuit voltage,
V ₂ is the maximum load end after the second time when the secondary storage battery is mounted on the vehicle.
The voltage between the children
I is the maximum load current after the second time when the secondary storage battery is mounted on the vehicle
It is.
... (C)
SOH (%) = [(Re-R) / (Re-R0)] × 100
... (D)
The method of determining the state of the secondary storage battery according to claim 1.

Measuring the temperature of the secondary storage battery,
Correcting the open circuit voltage and the terminal voltage at the measured temperature;
The method of determining the state of the secondary storage battery according to claim 1.

Calculate the current internal resistance by calculating an approximate expression using the calculated plurality of internal resistances as a variable of the number of engine starts,
The SOH is calculated from the current internal resistance, the initial internal resistance, and the limit internal resistance.
The method to determine the state of the secondary storage battery in any one of Claims 1-3 .

When the internal resistance of the secondary storage battery is the value of the initial internal resistance, SOH is 100%, and when the internal resistance of the secondary storage battery is the value of the limit internal resistance Re, SOH is 0%, and the internal resistance SOH corresponding to is expressed in%.
The method to determine the state of the secondary storage battery in any one of Claims 1-4 .

The process for obtaining the SOH is performed after a period during which the state of the secondary storage battery is stabilized after the secondary storage battery is used,
The method to determine the state of the secondary storage battery in any one of Claims 1-5 .

The secondary storage battery is a lead storage battery,
The method to determine the state of the secondary storage battery in any one of Claims 1-6 .

Only when the secondary battery is installed in the vehicle, the initial internal resistance and engine start limit are determined from the open circuit voltage of the secondary battery before the engine start period, the current flowing through the secondary battery during the engine start period, and the voltage between the terminals. A first calculating means for calculating a limit internal resistance;
After the second time when the secondary storage battery is mounted on the vehicle, every time the engine is started, the open circuit voltage of the secondary storage battery before the engine start period, the current flowing through the secondary storage battery during the engine start period, and the measured value of the voltage between the terminals Second calculating means for calculating the internal resistance using
The initial internal resistance, the limit internal resistance, and SOH calculating means for predicting the remaining life (SOH) of the secondary storage battery from at least one of the internal resistances. The state of the secondary storage battery mounted on the vehicle A device to determine.

The initial internal resistance is calculated by the following equation a,
The limit internal resistance is calculated by the following formula b,
The internal resistance R is calculated by the following equation c.
The SOH is calculated by the following equation _{d R0 = (E2-V max} ) / I max
Where E2 is an open circuit voltage,
V _max is the maximum load terminal voltage,
I _max is the maximum load current.
... (a)
Re = ((E2−Ve) × Ve) / W _max
Where E2 is an open circuit voltage,
Ve is the lower limit voltage that becomes the engine start limit,
W _max is the maximum load power required to start the engine.
... (b)
R = (E2-V ₂ ) / I
Where E2 is an open circuit voltage,
V ₂ is the maximum load end after the second time when the secondary storage battery is mounted on the vehicle.
The voltage between the children
I is the maximum load current after the second time when the secondary storage battery is mounted on the vehicle
It is.
... (c)
SOH (%) = [(Re-R) / (Re-R0)] × 100
... (d)
The apparatus which determines the state of the secondary storage battery of Claim 8 .

Temperature correction means for correcting the open circuit voltage and the inter-terminal voltage with the detected value of the temperature of the secondary storage battery,
The apparatus which determines the state of the secondary storage battery of Claim 8 or 9 .

Means for calculating a current internal resistance by calculating an approximate expression using the calculated plurality of internal resistances as a variable of the number of engine starts;
The SOH calculating means calculates the SOH from the calculated current internal resistance, the initial internal resistance, and the limit internal resistance.
The apparatus which determines the state of the secondary storage battery in any one of Claims 8-10 .

The SOH calculating means sets SOH when the internal resistance of the secondary storage battery is the value of the initial internal resistance to 100%, and sets the SOH when the internal resistance of the secondary storage battery is the value of the limit internal resistance Re to 0. %, And SOH corresponding to the internal resistance is expressed in%.
The apparatus which determines the state of the secondary storage battery in any one of Claims 8-11 .

Control means for operating the first and second calculation means and the SOH calculation means after a period during which the state of the secondary storage battery is stable after use of the secondary storage battery,
The apparatus which determines the state of the secondary storage battery in any one of Claims 8-12 .

The secondary storage battery is a lead storage battery,
The apparatus which determines the state of the secondary storage battery in any one of Claims 8-13 .

A voltmeter for measuring a voltage of a secondary storage battery mounted on the vehicle;
An ammeter for detecting a current flowing in the secondary storage battery;
Engine start signal generating means for generating a signal indicating engine start;
Only when the secondary storage battery is mounted on the vehicle, the open circuit voltage of the secondary storage battery before the engine start period is measured using the voltmeter, and the engine is started by a signal from the engine start signal generating means. In the engine starting period, the current flowing through the secondary storage battery using the ammeter and the voltage across the terminals using the voltmeter are measured, and the initial internal resistance and the engine starting limit are determined from these measured values. A first calculating means for calculating a limiting internal resistance,
After the second time when the secondary storage battery is mounted on the vehicle, the start of the engine is detected by a signal from the engine start signal generating means, and each time the engine is started, the secondary voltage is measured using the voltmeter before the engine start period. Measure the open circuit voltage of the storage battery, measure the current flowing through the secondary storage battery using the ammeter during the engine start period, the voltage across the terminals using the voltmeter, and use these measured values to determine the internal resistance A second calculating means for calculating R;
An apparatus for determining a state of a secondary storage battery mounted on a vehicle, comprising: the initial internal resistance; the limit internal resistance; and SOH calculating means for predicting a remaining life (SOH) from at least one of the internal resistances.

The initial internal resistance R0 is calculated by the following equation aa:
The limit internal resistance Re that becomes the limit of the engine start is calculated by the following formula bb,
The internal resistance R is calculated by the following formula cc:
The SOH is calculated by the following formula _{dd R0 = (E2-V max} ) / I max
Where E2 is an open circuit voltage,
V _max is the maximum load terminal voltage,
I _max is the maximum load current.
... (aa)
Re = ((E2−Ve) × Ve) / W _max
Where E2 is an open circuit voltage,
Ve is the lower limit voltage that becomes the engine start limit,
W _max is the maximum load power required to start the engine.
... (bb)
R = (E2-V ₂ ) / I
Where E2 is an open circuit voltage,
V ₂ is the maximum load end after the second time when the secondary storage battery is mounted on the vehicle.
The voltage between the children
I is the maximum load current after the second time when the secondary storage battery is mounted on the vehicle
It is.
... (cc)
SOH (%) = [(Re-R) / (Re-R0)] × 100
... (dd)
The apparatus which determines the state of the secondary storage battery of Claim 15 .

Temperature correction means for correcting the open circuit voltage and the inter-terminal voltage with the detected value of the temperature of the secondary storage battery,
The apparatus which determines the state of the secondary storage battery of Claim 15 or 16 .

Means for calculating a current internal resistance by calculating an approximate expression using the calculated plurality of internal resistances as a variable of the number of engine starts;
The SOH calculating means calculates the SOH from the calculated current internal resistance, the initial internal resistance R0, and the limit internal resistance Re.
The apparatus which determines the state of the secondary storage battery in any one of Claims 15-17 .

The SOH calculating means sets SOH when the internal resistance of the secondary storage battery is the value of the initial internal resistance to 100%, and sets the SOH when the internal resistance of the secondary storage battery is the value of the limit internal resistance Re to 0. %, And SOH corresponding to the internal resistance is expressed in%.
The apparatus which determines the state of the secondary storage battery in any one of Claims 15-18 .

Control means for operating the first and second calculation means and the SOH calculation means after a period during which the state of the secondary storage battery is stable after use of the secondary storage battery,
The apparatus which determines the state of the secondary storage battery in any one of Claims 15-19 .

The secondary storage battery is a lead storage battery,
The apparatus which determines the state of the secondary storage battery in any one of Claims 15-20 .