JP4369688B2

JP4369688B2 - Method and apparatus for determining remaining capacity of storage battery mounted on vehicle

Info

Publication number: JP4369688B2
Application number: JP2003166554A
Authority: JP
Inventors: 史和岩花; 敏幸佐藤; 秀人中村; 哲也加納; 克己稲庭
Original assignee: Furukawa Electric Co Ltd; Furukawa Battery Co Ltd
Current assignee: Furukawa Electric Co Ltd; Furukawa Battery Co Ltd
Priority date: 2003-06-11
Filing date: 2003-06-11
Publication date: 2009-11-25
Anticipated expiration: 2023-06-11
Also published as: JP2005001491A

Description

【０００１】
【発明の属する技術分野】
本発明は、自動車なと車両に搭載する充電可能な蓄電池の状態、たとえば、残存容量および蓄電池の劣化状態を判定する方法およびその装置に関する。
特に、本発明は、アイドリングストップ中など、蓄電池から放電が行われているときに蓄電池の残存容量またはＳＯＣを判定する方法と装置に関する。
また本発明は、蓄電池を搭載した車両において一時停車時に内燃機関を停止するアイドリングストップを行う車両に搭載した二次蓄電池の状態（残存容量および蓄電池の劣化状態）を判定する方法およびその装置に関する。
【０００２】
【従来の技術】
環境汚染を低減し、自動車の燃費の向上のため、自動車が交差点で信号待ちのために一時停車したときあるいは渋滞で停車しているときなど、内燃機関（エンジン）を一時的に停止するアイドリングストップ機能を有する自動車が知られている。
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自動車を再起動できるだけ車載の蓄電池に残存容量が存在すること、および／または、蓄電池の劣化状態を知ることが必要である。
【０００３】
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。しかしながら、これまで、車両のアイドリングストップの判断に適用する適切な車載の蓄電池の残存容量を実用的で簡便かつ正確に検出する方法は知られていない。
以下、蓄電池の残存容量の測定方法について概観する。
【０００４】
簡単かつ確実な蓄電池の残存容量測定方法は、蓄電池を完全に放電させて容量を測定し、その容量から劣化状態を判定する方法である。しかしながら、この方法は蓄電池を完全に放電させるので、当然ながら走行中の車両に搭載した蓄電池の残存容量を判定する場合には使用することはできない。しかもこの方法は放電するまでに長い時間がかかるので、測定時間が長くなるという問題がある。
【０００５】
以下、蓄電池を故意に放電させずに比較的短時間に蓄電池の残存容量の測定を行なう方法について述べる。
【０００６】
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、充電されると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、そのような蓄電池の残存容量を推定することはできない。
【０００７】
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。すなわち、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、この発明を車両の走行に伴って発電機から鉛蓄電池に充電される方式の車載の鉛蓄電池の残存容量に適用することはできない。その理由は、発電機から鉛蓄電池への影響、自動車に搭載された電気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、蓄電池の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。したがって、この発明を乗用車などの通常の自動車に適用するには課題がある。
【０００８】
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。この方法を「電流積算法」と呼ぶ。
このような単純に蓄電池からの放電電流または蓄電池への充電電流を積算するだけの電流積算法を、車両に搭載された蓄電池の残存容量の算出に、車両の起動時、車両の走行時およびアイドリングストップ期間の全期間に適用すると、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ことがある。
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）などに提案されている。
【０００９】
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行う必要があり、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ことから、内燃機関を搭載した自動車のアイドリングストップに適用できない。
【００１０】
【特許文献１】
特許第２５３６２５７号公報（特開平４−９５７８８号公報）
【特許文献２】
特許第２７９１７５１号公報（特開平８−１９１０３号公報）
【００１１】
【発明が解決しようとする課題】
以上、車両に搭載された蓄電池の残存容量を判定する種々の従来技術について述べたが、それらの技術は、特に、車両に搭載した車両のアイドリングストップ時に蓄電池から放電電流が流れるときの蓄電池の残存容量またはＳＯＣを正確に判定するには課題がある。
【００１２】
本発明の目的は、車両に搭載した二次蓄電池の残存容量および劣化状態（ＳＯＣ）の判定を、比較的簡単な方法で実現できる、方法と装置を提供することにある。
本発明の目的また、アイドリングストップ処理を行う車両に搭載した二次蓄電池の残存容量および劣化状態の判定を、比較的簡単な方法で実現できる方法と装置を提供することにある。
【００１３】
【課題を解決するための手段】
本発明の第１の観点によれば、車両に搭載された蓄電池の残存容量判定方法であって、電池容量の異なる複数の蓄電池に対して、各残存容量または充電状態の百分率に対する端子間電圧と、当該蓄電池の放電電流を当該蓄電池の満充電容量を示す数で除算した電流割合値の関係を示す関係式を事前に求めておき、
前記蓄電池が放電しているとき、
前記蓄電池の端子間電圧と放電電流を測定し、
前記測定した放電電流の値を事前に得られた前記蓄電池の満充電容量を示す数で除算した電流割合値を算出し、
前記事前に求めた、前記蓄電池の各残存容量または充電状態の百分率に対する端子間電圧と電流割合値の関係を示す前記関係式に、前記算出した電流割合値を代入して前記残存容量又は充電状態の百分率に対する端子間電圧を求め、
該求めた端子間電圧と、前記測定した端子間電圧値を比較対照して、前記蓄電池の残存容量又は充電状態の百分率を判定する
車両に搭載された蓄電池の残存容量判定方法が提供される。
【００１４】
好ましくは、前記関係式は下記の式で定義される。
Ｖ_Qn＝ａ_Qn ×Ｃ＋ｂ_Qn
ただし、ａ_Qn、ｂ_Qnは事前に求めた係数である。
【００１６】
前記蓄電池の各残存容量（Ｑ_n ）に対する端子間電圧（Ｖ_Qn）と電流割合値（Ｃ）の関係式を事前に求める工程において、満充電時の電池容量が前記各残存容量（Ｑ_n ）のいずれより大きな電池容量を有する蓄電池について、まず前記蓄電池の満充電時において、それぞれ一定の複数の第１の電流割合値の電流をごく短い時間の間だけ放電し、この時の端子間電圧を測定する第１の測定工程と、一定の第２の電流割合値の電流で放電を任意の時間継続して放電容量を調整する工程を所定の端子間電圧まで降下するまで繰り返して行う。
そして、一定の第２の電流割合値の電流（Ｉｄ２）で放電した時間の合計時間（Ｔ２）と一定の第２の電流割合値の電流（Ｉｄ２）との積で規定される第１の放電容量と、それぞれ一定の複数の第１の電流割合値（Ｉｄ１）とごく短い時間（Ｔ１）の積の総和である第１の測定工程にて放電される放電容量と、第１の測定工程を実施した回数（ｎ）の積で規定される第２の放電容量により、合計した第３の放電容量を蓄電池の全放電容量と規定し、前記繰り返し行う各第１の測定工程を実施する前までに、第２の電流割合値の電流による放電容量および第１の測定工程によって放電される放電容量の合計容量を、前記蓄電池の全放電容量から差し引いた各放電容量について、第１の特性を求めて第１の特性を近似式に表し、端子間電圧と電流割合値の関係式を求める。
【００１７】
好ましくは、前記アイドリングストップしているとき、下記式に基づいて前記蓄電池の残存容量を算出する。
【００１８】
【数２】
残存容量＝Ｑ_n ＋（Ｑ_n+1 −Ｑ_n ）×〔（Ｖ−Ｖ_Qn）／（Ｖ_Qn+1−Ｖ_Qn）〕
ただし、Ｑ_n 、Ｑ_n+1 は、残存容量であり、
Ｑ_n ＜Ｑ_n+1 であり、
Ｖ_Qnは残存容量Ｑ_n における測定された蓄電池の放電電流値からから算出した端子間電圧であり、下記式で表される電圧であり、
Ｖ_Qn＝α×Ｃ＋β
ここで、α、βは係数であり、
Ｃは電流割合値（測定放電電流値／満充電時の電池容量）であり、
Ｖ_Qn+1は残存容量Ｑ_n+1 における測定された蓄電池の放電電流値から算出した端子間電圧であり、下記式で表される電圧であり、
Ｖ_Qn+1＝γ×Ｃ＋δ
ここで、γ、δは係数であり、
Ｃは電流割合値（測定放電電流値／満充電時の電池容量）であり、
Ｖは測定した蓄電池の端子間電圧である。
【００１９】
上記の方法は、アイドリングストップ中など、蓄電池から放電電流が流れている場合に好適に適用できる。
【００２０】
上記方法の適用が難しい場合、たとえば、車両の走行中など、オルタネータ２による蓄電池の充電中に蓄電池の充電状態を判定する必要がある場合には、蓄電池の充電電流を測定して、公知の電流積算法を併用することができる。このような電流積算法は、特定の条件において実施するので、換言すれば、上述した蓄電池の残存容量を判定する全期間について実施するのではなく、電流積算法が適した場合のみ実施する。
また、車両の起動時または再始動時は、蓄電池からスタータおよび電気装備に流れる放電電流の積算値を事前に求めておき、１回の起動また再始動のたび、その放電容量を残存容量から減じる。
したがって、好ましくは、前記車両が走行中のとき、電流計で測定した充電電流を積算して前記鉛蓄電池３の残存容量を算出し、前記蓄電池が放電中のときに求めた残存容量と合計する。
また好ましくは、前記車両の起動または始動のとき、所定量の放電量を前記蓄電池の残存容量から減じる。
【００２１】
好ましくは、前記判定した残存容量が所定量以上のとき、アイドリングストップを行う。
【００２２】
本発明の第２の観点によれば、エンジンを起動するスタータと、エンジンによって動作するオルタネータと、電気装備と、車両の起動時または再始動時前記スタータおよび前記電気装備に給電し、車両の走行時に前記オルタネータから充電され、車両がアイドリングストップのとき前記電気装備に給電を行う蓄電池を搭載した、蓄電池の残存容量判定装置であって、
前記蓄電池の充放電電流を測定する電流計と、
前記蓄電池の端子間電圧を測定する電圧計と、
電池容量の異なる複数の蓄電池に対して、各残存容量または充電状態の百分率に対する端子間電圧と、当該蓄電池の放電電流を当該蓄電池の満充電容量を示す数で除算した電流割合値の関係を示す関係式の係数を記憶するメモリ手段と、
前記蓄電池が放電状態を検出したとき下記の諸手段を起動する放電状態検出手段と、
前記電流計で測定した前記蓄電池の放電電流、および、前記電圧計で測定した前記蓄電池の端子間電圧を読み取る手段と、
前記測定した放電電流の値を事前に得られた前記蓄電池の満充電容量を示す数で除算した電流割合値を算出する、電流割合値算出手段と、
前記メモリ手段に記憶されている前記関係式の係数を用いて、前記関係式に前記算出した電流割合値を代入して残存容量又は充電状態の百分率に対する端子間電圧を求める端子間電圧算出手段と、
該求めた端子間電圧と、前記測定した端子間電圧値を比較対照して、前記蓄電池の残存容量又は充電状態の百分率を判定する判定手段と
を有する、
車両に搭載された蓄電池の残存容量判定装置が提供される。
【００２３】
本発明においては、蓄電池の端子間電圧Ｖと電流Ｉを測定し、電流値Ｉを電池容量Ａｈを示す数値Ｑで除算した電流割合値Ｃを算出し、予め求めておいた、各残存容量又は充電状態（ＳＯＣ）の百分率に対する端子間電圧と電流割合値の関係式に、算出した電流割合値Ｃを代入することにより求められた、残存容量又はＳＯＣの百分率に対する端子間電圧と測定された端子間電圧値を比較対照することにより残存容量を判定することを特徴とする。
【００２４】
電流割合値Ｃは、満充電時の電池容量と等しい電流値を１Ｃという無次元量で表したものである。
例えば、蓄電池の満充電時の電池容量が５０Ａｈの場合、１Ｃは５０Ａである。また、満充電時の電池容量が５０Ａｈの蓄電池における充放電電流値２５Ａの電流割合値は２５／５０＝０．５Ｃであり、満充電時の電池容量が３０Ａｈの蓄電池における充放電電流値１５Ａと同じ電流割合値１５／３０＝０．５Ｃと同じ０．５Ｃである。このように満充電時の蓄電池の容量に対する充放電電流値の割合で電流の大きさを表現することが可能である。
従って電池容量の異なる各種の鉛蓄電池に対しても予め充電状態の百分率毎に求めた同一の電流割合値の関係式を適用することで充電状態の判定を行うことができる。
【００２５】
【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蓄電池の残存容量を判定する方法とその装置、および、蓄電池などの二次蓄電池の残存容量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。
【００２６】
図１は本発明のアイドリングストップ機能を有する車両に搭載された蓄電池の残存容量を判定する方法および装置、並びに、その判定結果に基づいてアイドリングストップ処理を行う方法と装置の第１実施の形態を図解した図である。
車両、たとえば、普通の乗用車には、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、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電装負荷を総称している。
【００２７】
スタータ１は、エンジンキーがオンにされた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。エンジン５の動作に伴うオルタネータ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への充電が行われる。
【００２８】
図１に図解したアイドリングストップ機能を有する車両に搭載された蓄電池の残存容量を判定する装置（以下、蓄電池の残存容量判定装置という）は、鉛蓄電池３に流れる電流を測定する電流計６と、鉛蓄電池３の端子電圧を測定する電圧計７と、鉛蓄電池３の残存容量を判定する判定手段８と、判定結果を表示する表示手段９を有する。
電流計６は、鉛蓄電池３に流れる電流（放電電流および充電電流）を測定する通常の直流電流計であり、符号−は放電電流を示し、符号＋は充電電流を示す。
電圧計７は、鉛蓄電池３の端子電圧を測定する通常の直流電圧計である。
表示手段９は、たとえば、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ができる。
【００２９】
エンジンキーの動作によりスタータ１が動作する車両の始動時、スタータ１がエンジン（内燃機関）５を起動するとオルタネータ２が動作して発電を行う。その後、電気装備４への給電はオルタネータ２から行われる。
エンジン５が回転動作している車両の走行中や、アイドリング中にはオルタネータ２が動作して発電しているから、鉛蓄電池３はオルタネータ２の発電電圧によって充電される。この時の鉛蓄電池３の端子間電圧はオルタネータ２の出力電圧に一致する。車両として普通の乗用車を例示すると、オルタネータ２の出力電圧は１４．５Ｖ程度である。
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。
アイドリングストップ処理手段１０の動作によって車両がアイドリングストップすると、エンジン５の回転が停止するのでオルタネータ２も停止してオルタネータ２による発電は停止する。そのとき鉛蓄電池３から電気装備４などへの給電が行われる。鉛蓄電池３からの電気装備４などへの給電（放電）により鉛蓄電池３の端子間電圧が低下していく。鉛蓄電池３の端子間電圧の低下は負荷電流に依存する。鉛蓄電池３を開放状態にして数時間以上経過した場合の鉛蓄電池３の端子間電圧は、充電状態の鉛蓄電池３が満充電状態のときは、１２．９Ｖ程度になる。したがって、負荷電流が流れているときの鉛蓄電池３の端子間電圧は１２．９Ｖよりも低下し、満充電状態であっても、たとえば、１２．５Ｖなどのように１２．９Ｖよりも低下することがある。このように、鉛蓄電池３の端子間電圧の低下は、負荷電流、換言すれば、鉛蓄電池３の放電電流に依存する。また、鉛蓄電池３の端子間電圧の低下は、残存容量、または充電状態（ＳＯＣ）によっても低下する。
【００３０】
図２は判定手段８の構成例を示す図である。
判定手段８は、マイクロコンピュータの中央演算処理装置（ＣＰＵ）８１と、ＲＡＭおよびＲＯＭなどのメモリ８２と、アナログ／ディジタル（Ａ／Ｄ）変換部８３と、入出力（Ｉ／Ｏ）ポート８４と、レギュレータ８５と，表示出力インタフェース（Ｉ／Ｆ）８６と、電流測定調整部８７と、電圧測定調整部８８とを有する。
判定手段８は、本発明のメモリ手段、放電状態検出手段、放電電流および端子間電圧を読み取る手段、電流割合値算出手段、端子間電圧算出手段、蓄電池の残存容量またはＳＯＣの百分率を判定する手段として機能する。
【００３１】
ＣＰＵ８１は、下記に述べる種々の処理を行う。以下、判定手段８の処理という場合、主としてＣＰＵ８１で行う処理を意味する。ＣＰＵ８１は、放電状態検出手段、放電電流および端子間電圧を読み取る手段、電流割合値算出手段、端子間電圧算出手段、蓄電池の残存容量またはＳＯＣの百分率を判定する手段として機能する。
メモリ８２のＲＯＭにはＣＰＵ８１で行う各種のプログラムが記憶されている。
メモリ８２のＲＡＭには後述する関係式（の係数）が記憶されている他、電流計６の測定値、電圧計７の測定値、演算処理データなどが記憶される。したがって、メモリ８２のＲＡＭは本発明のメモリ手段に該当する。ＲＡＭは、車両の停止期間でも、上記記憶した各種のデータが保持されるように、かつ、新たなデータの書き込みが可能なように、書き換え可能な不揮発性メモリが好ましい。
Ａ／Ｄ変換部８３は、アナログ電圧信号として表される電流計６および電圧計７の測定結果を入力して、ＣＰＵ８１で処理するディジタル信号に変換する。
Ｉ／Ｏポート８４は、ディジタル形式のエンジン５の始動信号および再始動信号を入力する入力ポートと、アイドリングストップ処理手段１０などに判定手段８の判定結果を示すディジタル信号を出力する出力ポートとを有する。
表示出力インタフェース（Ｉ／Ｆ）８６は表示手段９への出力に用いる。
【００３２】
レギュレータ８５はエンジン５のエンジンキーの動作に連動して印加される電源電圧を入力して、ＣＰＵ８１、メモリ８２、Ａ／Ｄ変換部８３、Ｉ／Ｏポート８４の駆動電圧に調整する。
判定手段８を構成するＣＰＵ８１、メモリ８２、Ａ／Ｄ変換部８３、Ｉ／Ｏポート８４は、オルタネータ２、鉛蓄電池３などから給電されるが、ＣＰＵ８１などは通常、３〜５ＶＤＣで動作する。しかし、オルタネータ２、鉛蓄電池３の電圧は電気装備４など車両に搭載された種々の電気製品を駆動するため、たとえば、オルタネータ２の出力電圧が１４．５Ｖ程度であるように電圧が高い。そこで、レギュレータ８５において、そのような高電圧をＣＰＵ８１などが動作可能な電圧に調整している。
【００３３】
Ａ／Ｄ変換部８３の入力電圧範囲は、たとえば、０〜±５Ｖ程度であるから、電流計６を用いた場合のように、その検出電圧が非常に低い時は電流測定調整部８７で０〜５Ｖに増幅する。同様に、電圧計７の検出電圧が０〜１５Ｖ程度の高いときは電圧測定調整部８８で０〜５Ｖに分圧する。電流計６の検出信号および／または電圧計７の検出信号のレベルを判定手段８の外部でＡ／Ｄ変換部８３の入力電圧範囲に調整している場合は、電流測定調整部８７および電圧測定調整部８８は不要である。
【００３４】
上記蓄電池の残存容量判定装置に、アイドリングストップ処理手段１０を付加すると、蓄電池の残存容量判定装置の結果に基づいて車両のアイドリングストップ処理を行うことができる。
図１に図解したように、蓄電池の残存容量判定装置にアイドリングストップ処理手段１０を付加した構成が、車両に搭載された蓄電池の残存容量を判定し、アイドリングストップ処理機能を有する装置となる。
【００３５】
鉛蓄電池３の充放電特性
図３は、鉛蓄電池３が搭載された車両における、▲１▼の起動時（始動時）、▲２▼の走行中および▲３▼のアイドリングストップ中の蓄電池の充放電電流波形である。横軸は時間経過を示し、縦軸は電流を示す。なお、縦軸に示した蓄電池への充電電流を＋で示し、蓄電池からの放電電流を−で示している。
▲１▼の期間、すなわち、エンジンキーが回転されてエンジン５が始動したとき、エンジン５を動作させるスタータ１を動作させるため鉛蓄電池３からスタータ１に大きな放電電流（−）が流れる。
▲２▼の期間、すなわち、車両の始動後の車両の走行中においては、エンジン５が動作してオルタネータ２が動作するので、発電機（オルタネータ）２からの電気装備４に給電されるとともに、充電電流が鉛蓄電池３に流れ鉛蓄電池３が充電される。
▲３▼の期間、すなわち、アイドリングストップ処理手段１０がアイドリング可能と判断してアイドリングストップ中は、エンジン５が停止しているためオルタネータ２も停止するから、電気装備４に鉛蓄電池３から一定の放電電流（−の平坦曲線）が流れる。
【００３６】
上述した▲１▼〜▲３▼の期間の鉛蓄電池３への充放電状態を▲４▼〜▲６▼に簡略化して図解している。
▲４▼の期間のうち、▲３▼の最後と▲４▼の最初の間は、アイドリングストップ終了後、エンジン５を再始動させるためにスタータ１を起動するため、▲１▼の期間と同様、鉛蓄電池３からスタータ１に大きな放電電流が流れる（−）。もちろん、鉛蓄電池３から電気装備４への給電も行われている。
エンジン５が再始動してオルタネータ２が動作すると、▲２▼の立ち上がり時と同様、オルタネータ２によって鉛蓄電池３が充電される（＋の充電電流）。
アイドリングストップ状態になると、鉛蓄電池３から電気装備４などに放電電流が流れる（−の一定の値の放電電流）。
▲４▼と▲５▼の間のアイドリングストップ終了後、スタータ１を起動するため、鉛蓄電池３からスタータ１に放電電流が流れる。
【００３７】
▲５▼の期間は、▲４▼の期間と同様であるが、▲５▼の期間は走行期間が長くアイドリングストップ時間が短い。
【００３８】
鉛蓄電池３の放電電流または充電電流は、電流計６で測定でき、鉛蓄電池３の端子電圧は電圧計７で測定できる。判定手段８、特に、ＣＰＵ８１は、電流計６および電圧計７の測定値を読み込んで、それらの測定値を参照して鉛蓄電池３の残存容量およびＳＯＣの判定を行う。
【００３９】
以下、図１および図２に図解した蓄電池の残存容量判定装置における車両用鉛蓄電池の充電状態判定処理について述べる。
【００４０】
ＳＯＣの判定処理
図３の▲２▼の期間の車両の走行中においては、鉛蓄電池３にはオルタネータ２から充電電流が流れることが多い。
▲３▼の期間のアイドリングストップ中においては、エンジン５が停止しているからオルタネータ２において発電は行われず、鉛蓄電池３への充電は行われていず、むしろ、鉛蓄電池３から電気装備４などの電装負荷へ充電電流が流れる。
アイドリングストップは、アイドリングストップ処理手段１０においてアイドリングストップ可能と判断した場合、特に、鉛蓄電池３の残存容量がアイドリングストップし、再始動可能なだけ残存していることを判断したとき、アイドリングストップに移行する。
【００４１】
判定手段８が行うアイドリングストップ中の鉛蓄電池３の残存容量の判定方法の詳細を図４のフローチャートを参照して述べる。
【００４２】
ステップ１：事前処理として、オペレータは、図５に例示した、予め求めておいた各残存容量またはＳＯＣの百分率に対する端子間電圧Ｖと電流割合値Ｃの関係式（図５参照）を判定手段８のメモリ８２のＲＡＭに記憶する。
なお、図５に例示した関係式は、後述する式１に示すように、一次直線で近似できるから、メモリ８２のＲＡＭに、各直線の係数ａ_Qn、ｂ_Qnをを記憶しておけばよい。
この関係式の内容および求め方（測定方法）については後述する。
【００４３】
ステップ２：判定手段８（ＣＰＵ８１）は、Ｉ＜設定放電電流値を満たしたら、下記の処理を連続して行う。満たさなかった場合、電流積算法により、残存容量を算出する。
（１）ステップ３：ＣＰＵ８１は、鉛蓄電池３から流れる放電電流を電流計６で測定し、同時に鉛蓄電池３の端子間電圧を電圧計７で測定する。
（２）ステップ４：電流計６で測定した放電電流値Ｉを鉛蓄電池３の満充電容量を示す数値Ｑ（Ａｈ）で除算した電流割合値Ｃ（＝Ｉ／Ｑ）を算出する。
（３）ステップ５：判定手段８は、ステップ１において予め求めておいた鉛蓄電池３の各残存容量またはＳＯＣの百分率に対する端子間電圧Ｖと電流割合値Ｃの関係式に、ステップ４において算出した電流割合値Ｃを代入することにより鉛蓄電池３の残存容量またはＳＯＣの百分率に対する端子間電圧を求める。
（４）ステップ６：ＣＰＵ８１は、ステップ５において求めた端子電圧と、電圧計７で測定した端子間電圧値を比較対照することにより、鉛蓄電池３の充電状態またはＳＯＣを判定する。
（５）ステップ７：ＣＰＵ８１は、車両の運転が終了するまで、ステップ２〜６の処理を反復する。
【００４４】
残存容量又はＳＯＣの計算方法の詳細
図５は鉛蓄電池３からの放電電流と鉛蓄電池３の端子間電圧の測定値から残存容量またはＳＯＣを計算する際に使用するデータを示すグラフである。図中のプロットについての詳細は後述する。縦軸は鉛蓄電池３の端子間電圧を示し、横軸は鉛蓄電池３の満充電容量Ｑ（Ａｈ）に対する電流値Ｉの割合、すなわち、電流割合値Ｃ（＝Ｉ／Ｑ）を示す。
図５の図解から、電流割合値Ｃが大きくなると、つまり鉛蓄電池３の放電電流が増加すると鉛蓄電池３の端子間電圧が低下することが分かる。そして、鉛蓄電池３の電流割合値Ｃ（放電電流Ｉ）と端子間電圧Ｖの関係は線形性（直線関係）があることが分かる。したがって、図５の各残存容量Ｑ₁ 〜Ｑ₉ における算出すべき各端子間電圧Ｖ_n と電流割合値Ｃとの関係式は下記一次式で表される。
【００４５】
【数３】
Ｖ_Qn＝ａ_Qn×Ｃ＋ｂ_Qn
ただし、ａ_Qnは残存容量Ｑ_n における第１の係数であり、
ｂ_Qnは残存容量Ｑ_n における第２の係数である。
・・・（１）
【００４６】
図４のステップ１において、メモリ８２のＲＡＭに記憶する関係式として、一次直線の式の上記係数ａ_Qn、ｂ_Qnを記憶する。
図４のステップ６において、図５に例示したデータを使用して、鉛蓄電池３の現在の残存容量あるいはＳＯＣの水準を判定するには、式１に示す関係式に、電流計６で測定した電流値からステップ４において求めた電流割合値Ｃを代入して各残存容量又は各ＳＯＣの端子間電圧値Ｖを求め（ステップ５）、算出した端子間電圧と実際に電圧計７で測定した端子間電圧とを比較することで、鉛蓄電池３の残存容量の水準判定することができる。すなわち、鉛蓄電池３の端子電圧は、残存容量を示しているから、算出した端子間電圧と実際に電圧計７で測定した端子間電圧とを比較することにより、鉛蓄電池３の残存容量を推定することができる。
【００４７】
残存容量の推定方法
さらに、鉛蓄電池３の残存容量又はＳＯＣの値を見積もる（推定する）場合には、概略値として下記式を使用して算出することができる。
下記式２は鉛蓄電池３の現在の残存容量がＱｎのときの鉛蓄電池３の放電電流値と端子間電圧値Ｖ_Qnの関係を表す１次式である。
下記式３は鉛蓄電池３の前回の残存容量がＱ_n+1 のときの鉛蓄電池３の放電電流値と端子間電圧値Ｖ_Qn+1の関係を表す１次式である。
Ｖ_Qn、Ｖ_Qn+1はそれぞれ、残存容量Ｑ_n 、残存容量Ｑ_n+1 における測定された蓄電池の放電電流値から算出した端子間電圧値である。なお、ここでは、（Ｑ_n＜Ｑ_n+1 ）とする。
α，β，γ，δはそれぞれ係数であり、Ｃは電流割合値である。
係数α，β，γ，δは判定手段８のメモリ８２のＲＡＭに記憶されている。
電流割合値Ｃは、Ｃ＝（測定した鉛蓄電池３の電流（Ａ））／（鉛蓄電池３の満充電時の容量Ｑ（Ａｈ））で規定される。
【００４８】
【数４】
Ｖ_Qn＝α×Ｃ＋β ・・・（２）
【００４９】
【数５】
Ｖ_Qn+1＝γ×Ｃ＋δ ・・・（３）
【００５０】
式４は鉛蓄電池３の残存容量を求める式である。
Ｖは電圧計７で測定した鉛蓄電池３の端子間電圧である。
【００５１】
【数６】
残存容量＝Ｑ_n ＋（Ｑ_n+1 −Ｑ_n ）×〔（Ｖ−Ｖ_Qn）／（Ｖ_Qn+1−Ｖ_Qn）〕
ただし、Ｑ_n 、Ｑ_n+1 は、残存容量であり、
Ｑ_n ＜Ｑ_n+1 であり、
Ｖ_Qnは残存容量Ｑ_n における測定された蓄電池の放電電流値からから算出した端子間電圧であり、
Ｖ_Qn+1は残存容量Ｑ_n+1 における測定された蓄電池の放電電流値から算出した端子間電圧である。
・・（４）
【００５２】
式１〜４を用いると、判定手段８（ＣＰＵ８１）において、鉛蓄電池３の残存容量あるいはＳＯＣの百分率を計算することが可能になる。
【００５３】
鉛蓄電池３が放電しているときの残存容量またはＳＯＣの判定方法の具体例を述べる。
たとえば、鉛蓄電池３の放電電流値Ｉ＝１２．５Ａ、端子間電圧値Ｖ＝２４．２Ｖ、車両に搭載されている鉛蓄電池３の満充電時の電池容量Ｑ＝５０Ａｈの場合、電流割合値ＣはＣ＝（測定した鉛蓄電池３の電流（Ａ））／（鉛蓄電池３の満充電時の容量Ｑ（Ａｈ））から、（１２．５／５０＝）０．２５Ｃとなり、図５において、横軸の端子電圧Ｖ＝２４．２Ｖと、横軸の電流割合値Ｃ＝０．２５との交点（黒丸で示した部分）としてプロットすることができる。
プロットされた交点の上下に位置する部分の残存容量を、残存容量Ｑ₅＝２５Ａｈ、Ｑ₆＝３０Ａｈとすると、プロットされた交点の残存容量は２５Ａｈ以上３０Ａｈ以下となる。
【００５４】
図５の各残存容量又は各ＳＯＣにおける蓄電池の電流割合値Ｃと端子間電圧Ｖ₅、Ｖ₆の関係は、α＝−２．１２、β＝＋２４．５８を適用してＶ₅＝−２．１２Ｃ＋２４．５８、γ＝−２．２０，δ＝＋２４．８４を適用してＶ₆＝−２．２０Ｃ＋２４．８４であるから、電流割合値Ｃ＝０．２５Ｃにおける残存容量Ｑ₅、Ｑ₆の時の電圧値はＶ₅＝２４．０５、Ｖ₆＝２４．２９となる。
よって、判定手段８のＣＰＵ８１において補間処理を行うと、残存容量は、２５＋（３０−２５）×〔（２４．２−２４．０５）／（２４．２９−２４．０５）〕＝２８．１３Ａｈとして求めることができる。
【００５５】
また、判定手段８のＣＰＵ８１において、上記のごとく求めた残存容量２８．１３Ａｈを鉛蓄電池３の満充電時の電池容量Ｑ＝５０Ａｈで除算し、ＳＯＣの百分率＝５６．３％を求めてもよい。
【００５６】
端子間電圧と電流割合の関係式の作成方法
図６を参照して図５に示した端子間電圧と電流割合値の関係式の作成方法を述べる。図６は放電したときの鉛蓄電池３の端子間電圧を実測したグラフである。
（１）たとえば、満充電時の電池容量が５０Ａｈの鉛蓄電池３の場合、鉛蓄電池３を満充電状態とし、図６に示すように、Ｃに換算した電流割合値Ｃ１をＴ１１時間（Ｔ１１秒間）、電流割合値Ｃ２、Ｃ３をそれぞれＴ１２時間（Ｔ１２秒間）、電流割合値Ｃ４をＴ１３時間（Ｔ１３秒間）連続して放電させて、その際の蓄電池の端子間電圧を電圧計７で実測した。
（２）次いで、鉛蓄電池３の残存容量又はＳＯＣを調整するために電流割合値Ｃに換算した電流割合値Ｃ５で定電流放電をＴ２１時間（Ｔ２１秒間）行った。
（３）その後、再度、電流割合値Ｃ１をＴ１１秒、電流割合値Ｃ２、Ｃ３をそれぞれＴ１２秒間、電流割合値Ｃ４をＴ１３秒間連続して放電させて、その際の鉛蓄電池３の端子間電圧を電圧計７で実測した。
（４）再び、鉛蓄電池３の残存容量を調整するために電流割合値Ｃ５で定電流放電をＴ２１時間実施して、電流割合値Ｃ１をＴ１１秒間、電流割合値Ｃ２、Ｃ３をそれぞれＴ１２秒間、電流割合値Ｃ４をＴ１３秒間連続して放電させて、その際の鉛蓄電池３の端子間電圧を電圧計７で実測することを繰り返し実施し、鉛蓄電池３の電池容量がなくなるまで放電を行った。電池容量がなくなる条件の判断としては、鉛蓄電池３として１２Ｖ車用電池を使用の場合、端子電圧が１０．５Ｖに低下した時とした。
【００５７】
実測した端子間電圧は、図６を参照すると蓄電池から電流割合値の電流Ｃ１で放電し始めてＴ１１秒目の電圧、同様に電流割合値の電流Ｃ２、Ｃ３で放電し始めてＴ１２秒目の電圧および電流割合値の電流Ｃ４で放電し始めてＴ１３秒目の電圧値である。
このようにして蓄電池の各残存容量における電流割合値を変化させたときの端子間電圧を測定することにより、図５に図解した端子間電圧と電流割合値の関係式を作成することができる。
【００５８】
図５に図解した関係式を求める他の方法としては、各電流割合値Ｃで、鉛蓄電池３の電池容量がなくなることの判定条件である１０．５Ｖまで放電し、その後電流割合値０．２Ｃで放電し合計したものを電池容量とし、合計したものから放電容量を差し引いた容量を各残存容量として、そのときの端子間電圧値を求めても良い。
【００５９】
端子間電圧と電流割合値の関係式の共有化
鉛蓄電池３の残存容量又はＳＯＣを判定するときは、上述した電流積算法と、蓄電池からの放電電流値と端子間電圧値を測定し端子間電圧と放電電流値の関係式を参照することにより算出する方法との２つの方法がある。
図７（Ａ）、（Ｂ）は、満充電時の電池容量が異なる蓄電池の電流と電圧の関係を示している。図７（Ａ）は横軸を放電電流値としており、図７（Ｂ）は横軸を電流割合値としている。縦軸は共に端子間電圧である。
図７（Ｂ）に図解のごとく、横軸を図７（Ａ）に図解した電流値から電流割合値にすることにより、満充電時の電池容量が異なる電池でも端子間電圧と電流割合値で示す電流の関係は、実線で示した特性と破線で示した特性がほぼ一致し、ほぼ同等であることがわかる。これは、満充電時の電池容量に応じた電流割合値の電流で放電することによって放電時の端子間電圧の特性がほぼ同様になるからである。よって、満充電時の電池容量が異なる蓄電池においても、同様のデータを使用して鉛蓄電池３の残存容量またはＳＯＣの判定が可能となる。
【００６０】
このように、本発明の第１実施の形態によれば、車両に搭載されている蓄電池の充電状態を判定するとき、蓄電池からの電流と端子間電圧とを測定し、予め用意しておいた各残存容量に対する端子間電圧と電流割合値と比較対照することで残存容量の判定を行い、残存容量判定に使用する関係式に、電流割合値を使用することにより、同一電池種別の満充電時の電池容量の異なる蓄電池を網羅した端子間電圧と電流割合値の関係を１種類用意するのみで対応可能となることから、蓄電池のメーカー別に端子間電圧と電流割合値の関係を測定するのみで対応することが出来る。
【００６１】
さらに、アイドリングストップ機能を有する普通車、軽自動、大型バスや大型トラック、それぞれの適用されている蓄電池種別毎にほぼ同様の装置を適用することが可能であり、その点で大量生産により装置価格を格段に低くすることが可能である。
【００６２】
上記実施の形態においては、二次蓄電池３として鉛蓄電池３を例示したが、本発明の適用に際しては二次蓄電池３であれば、鉛蓄電池に限定されない。ただし、上述したしきい値などの特性データは選択した二次蓄電池に応じて変更する必要はある。
【００６３】
第２実施の形態
アイドリングストップ処理手段１０は、上述した方法で算出した鉛蓄電池３の残存容量が、アイドリングストップ中、電気装備４に鉛蓄電池３から給電することが可能であり、さらに、アイドリングストップ終了後、鉛蓄電池３からスタータ１に給電してスタータ１を駆動することが可能な十分な残存容量があることを判断して、車両が所定時間継続して停止した場合など、アイドリングストップ状態に入る。
【００６４】
アイドリングストップ処理手段１０は、アイドリングストップ中、上述した方法で鉛蓄電池３の残存容量が更新されているのを監視して、アイドリングストップ状態を継続できるか否かを判断する。
たとえば、アイドリングストップ期間が長く、電気装備４への給電により鉛蓄電池３の残存容量がスタータ１を再起動させるだけの残存容量が不足するようにな事態が発生する前に、アイドリングストップ処理手段１０はアイドリングストップを終了して、スタータ１を始動させる。
【００６５】
本発明の第１実施の形態によって、鉛蓄電池３の残存容量またはＳＯＣが正確に測定されているのでアイドリングストップ処理も正確に行うことができる。
【００６６】
【発明の効果】
本発明のアイドリングストップ機能を有する車両に搭載された蓄電池の残存容量を判定する方法および装置によれば、簡単な構成または処理方法であり、実現が容易であり、実用化に適している。
【００６７】
また、本発明のアイドリングストップ機能を有する車両に搭載された蓄電池の残存容量を判定する方法および装置によれば、信頼性の高いアイドリングストップ処理が可能となる。
【図面の簡単な説明】
【図１】図１は本発明のアイドリングストップ機能を有する車両に搭載された蓄電池の残存容量を判定する装置の１実施の形態の構成図である。
【図２】図２は図１に図解した装置構成の具体例を図解した図である。
【図３】図３は走行中・アイドリングストップ中における蓄電池の電流波形の例を示すグラフである。
【図４】図４はアイドリングストップ中における鉛蓄電池の残存容量またはＳＯＣを判定する、判定手段のＣＰＵにおける処理方法を示すフローチャートである。
【図５】図５は鉛蓄電池の残存容量又はＳＯＣを計算する際に使用する蓄電池の端子間電圧と電流割合値の関係式を示すグラフである。
【図６】図６は放電したときの鉛蓄電池３の端子間電圧を実測したグラフである。
【図７】図７（Ａ）、（Ｂ）は満充電時の電池容量が異なる蓄電池の電流と電圧の関係を示したグラフであり、図７（Ａ）は横軸を放電電流値とし、図７（Ｂ）は横軸を電流割合値としたグラフである。
【符号の説明】
１・・スタータ、２・・オルタネータ・３・・二次蓄電池（鉛蓄電池）
４・・電気装備、５・・エンジン、６・・電流計、７・・電圧計
８・・判定手段
８１・・ＣＰＵ、８２・・メモリ、８３・・Ａ／Ｄ変換部
８４・・Ｉ／Ｏポート、８５・・レギュレータ、
８６・・表示出力インタフェース（Ｉ／Ｆ）、
８７・・電流測定調整部、８８・・電圧測定調整部
９・・表示手段、１０・・アイドリングストップ処理手段[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and an apparatus for determining a state of a rechargeable storage battery mounted on a vehicle such as an automobile, for example, a remaining capacity and a deterioration state of the storage battery.
In particular, the present invention relates to a method and apparatus for determining the remaining capacity or SOC of a storage battery when discharging from the storage battery, such as during idling stop.
The present invention also relates to a method and an apparatus for determining a state of a secondary storage battery (remaining capacity and a deterioration state of a storage battery) mounted on a vehicle that performs idling stop for stopping an internal combustion engine when the vehicle is temporarily stopped.
[0002]
[Prior art]
An idling stop that temporarily stops the internal combustion engine (engine) when the vehicle is temporarily stopped for traffic lights at traffic lights or at traffic jams, etc., in order to reduce environmental pollution and improve vehicle fuel efficiency. A car having a function is known.
When performing such idling stop, it is necessary to know that there is a remaining capacity in the in-vehicle storage battery and / or to know the deterioration state of the storage battery as much as possible after restarting the automobile after idling stop.
[0003]
Various methods for measuring the remaining capacity of a storage battery have been tried. However, until now, there has been no known method for practically, simply and accurately detecting the remaining capacity of an on-vehicle storage battery that is applicable to the determination of idling stop of a vehicle.
Hereinafter, an overview of a method for measuring the remaining capacity of a storage battery will be given.
[0004]
A simple and reliable method for measuring the remaining capacity of a storage battery is a method in which the storage battery is completely discharged, the capacity is measured, and the deterioration state is determined from the capacity. However, since this method completely discharges the storage battery, it cannot be used when determining the remaining capacity of the storage battery mounted on the running vehicle. Moreover, since this method takes a long time to discharge, there is a problem that the measurement time becomes long.
[0005]
Hereinafter, a method for measuring the remaining capacity of the storage battery in a relatively short time without intentionally discharging the storage battery will be described.
[0006]
Since lead acid batteries produce water by discharging and sulfuric acid by charging, the specific gravity of the aqueous sulfuric acid solution decreases when discharged, and the specific gravity of the aqueous sulfuric acid solution returns to its original value when charged. A method of estimating the remaining capacity by using the specific gravity of the electrolytic solution as an index using this phenomenon 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. Since it is difficult to measure the specific gravity of the electrolyte for such a sealed lead-acid battery, the remaining capacity of such a battery cannot be estimated.
[0007]
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. That is, 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, the electrolyte resistance RΩ, the charge transfer resistance Rct, Apply an equivalent circuit consisting of the multilayer capacitance Cd, Warburg impedance W, and Warburg coefficient σ to find the 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, the present invention cannot be applied to the remaining capacity of a vehicle-mounted lead storage battery in which the lead storage battery is charged from the generator as the vehicle travels. The reason is that it is difficult to measure the internal impedance of the lead-acid battery due to the influence of the generator on the lead-acid battery and the influence of load fluctuations of the electrical equipment mounted on the automobile. If the internal impedance of the lead storage battery cannot be measured, it cannot be compared with the initial value, and the life of the storage battery 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. Therefore, there is a problem in applying the present invention to ordinary automobiles such as passenger cars.
[0008]
A method is also known 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. This method is called “current integration method”.
Such a current integration method that simply integrates the discharge current from the storage battery or the charging current to the storage battery is used to calculate the remaining capacity of the storage battery installed in the vehicle. When applied to the entire stop period, the error of the integrated value gradually increases due to the measurement error of the current value, and the state of the storage battery may not be obtained accurately.
Therefore, a method improving the “current integration method” has been proposed in Japanese Patent No. 2791751 (Japanese Patent Laid-Open No. 8-19103).
[0009]
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, the present invention cannot be applied to an idling stop of an automobile equipped with an internal combustion engine because it is difficult to measure the internal impedance described above.
[0010]
[Patent Document 1]
Japanese Patent No. 2536257 (Japanese Patent Laid-Open No. 4-95788)
[Patent Document 2]
Japanese Patent No. 2791751 (Japanese Patent Laid-Open No. 8-19103)
[0011]
[Problems to be solved by the invention]
As described above, various conventional techniques for determining the remaining capacity of the storage battery mounted on the vehicle have been described. However, these techniques particularly relate to the remaining of the storage battery when a discharge current flows from the storage battery when the vehicle mounted on the vehicle is idling stopped. There is a problem in accurately determining the capacity or SOC.
[0012]
The objective of this invention is providing the method and apparatus which can implement | achieve the determination of the remaining capacity and deterioration state (SOC) of the secondary storage battery mounted in the vehicle by a comparatively simple method.
It is another object of the present invention to provide a method and apparatus that can determine the remaining capacity and deterioration state of a secondary storage battery mounted on a vehicle that performs an idling stop process by a relatively simple method.
[0013]
[Means for Solving the Problems]
  According to a first aspect of the present invention, there is provided a method for determining a remaining capacity of a storage battery mounted on a vehicle,For multiple storage batteries with different battery capacities,The voltage across the terminals for each remaining capacity or percentage of charge,The discharge current of the storage battery is divided by a number indicating the full charge capacity of the storage battery.Obtain a relational expression showing the relationship of the current ratio value in advance,
  When the storage battery is discharged,
    Measure the inter-terminal voltage and discharge current of the storage battery,
    MeasuredDischarge current valueThe full charge capacity of the storage battery obtained in advanceWith a number indicatingCalculate the divided current ratio value,
    The relationship between the terminal voltage and the current ratio value with respect to the remaining capacity or the percentage of the charged state of the storage battery obtained in advance is shown.AboveSubstituting the calculated current ratio value into the relational expressionAboveRemaining capacity orState of chargeFind the voltage across the terminals for the percentage of
    Comparing and comparing the obtained inter-terminal voltage and the measured inter-terminal voltage value, the remaining capacity of the storage battery orState of chargeDetermine the percentage of
  A method for determining a remaining capacity of a storage battery mounted on a vehicle is provided.
[0014]
Preferably, the relational expression is defined by the following formula.
V_Qn= A_Qn  × C + b_Qn
However, a_Qn, B_QnIs a coefficient obtained in advance.
[0016]
Each remaining capacity (Q_n Between terminals (V)_Qn) And the current ratio value (C) in advance, the battery capacity at the time of full charge is the remaining capacity (Q_n For the storage battery having a battery capacity larger than any of the above, first, when the storage battery is fully charged, each of the constant first current ratio values is discharged for a very short time, and the inter-terminal voltage at this time The first measurement step of measuring the current and the step of adjusting the discharge capacity by continuing the discharge for a predetermined time with the current having the constant second current ratio value are repeated until the voltage drops to a predetermined inter-terminal voltage.
Then, the first discharge defined by the product of the total time (T2) of the discharge time at the constant second current ratio value current (Id2) and the constant second current ratio value current (Id2). A capacity, a discharge capacity discharged in the first measurement step, which is the sum of products of a plurality of first current ratio values (Id1) and a very short time (T1), and the first measurement step. Until the total of the third discharge capacity is defined as the total discharge capacity of the storage battery by the second discharge capacity defined by the product of the number of times (n) performed, and before each first measurement step that is repeated is performed. In addition, the first characteristic is obtained for each discharge capacity obtained by subtracting the total discharge capacity of the storage battery from the discharge capacity due to the current of the second current ratio value and the discharge capacity discharged by the first measurement step. The first characteristic is expressed by an approximate expression, and the voltage and current between terminals are Determine the relationship of the case value.
[0017]
Preferably, when the idling is stopped, the remaining capacity of the storage battery is calculated based on the following equation.
[0018]
[Expression 2]
Remaining capacity = Q_n + (Q_{n + 1} -Q_n ) X [(V-V_Qn) / (V_{Qn + 1}-V_Qn)]
However, Q_n , Q_{n + 1} Is the remaining capacity,
Q_n <Q_{n + 1} And
V_QnIs the remaining capacity Q_n Is a voltage between terminals calculated from the measured discharge current value of the storage battery in
V_Qn= Α x C + β
Where α and β are coefficients,
C is a current ratio value (measured discharge current value / battery capacity at full charge),
V_{Qn + 1}Is the remaining capacity Q_{n + 1} Is a voltage between terminals calculated from the measured discharge current value of the storage battery in
V_{Qn + 1}= Γ × C + δ
Where γ and δ are coefficients,
C is a current ratio value (measured discharge current value / battery capacity at full charge),
V is the measured inter-terminal voltage of the storage battery.
[0019]
The above method can be suitably applied when a discharge current is flowing from the storage battery, such as during idling stop.
[0020]
When it is difficult to apply the above method, for example, when the storage battery needs to be determined during charging of the storage battery by the alternator 2 such as when the vehicle is running, the charging current of the storage battery is measured and a known current is measured. An integration method can be used in combination. Since such a current integration method is performed under specific conditions, in other words, it is not performed for the entire period for determining the remaining capacity of the storage battery described above, but only when the current integration method is suitable.
When the vehicle is started or restarted, the integrated value of the discharge current flowing from the storage battery to the starter and the electrical equipment is obtained in advance, and the discharge capacity is reduced from the remaining capacity at each start-up or restart. .
Therefore, preferably, when the vehicle is running, the remaining current of the lead storage battery 3 is calculated by integrating the charging current measured by an ammeter and summed with the remaining capacity obtained when the storage battery is discharging. .
Preferably, when the vehicle is started or started, a predetermined amount of discharge is subtracted from the remaining capacity of the storage battery.
[0021]
Preferably, idling stop is performed when the determined remaining capacity is equal to or greater than a predetermined amount.
[0022]
  According to the second aspect of the present invention, a starter for starting the engine, an alternator operated by the engine, electrical equipment, and supplying power to the starter and the electrical equipment at the time of starting or restarting the vehicle, A storage battery remaining capacity determination device that is sometimes charged from the alternator and includes a storage battery that feeds power to the electrical equipment when the vehicle is idling stop,
  An ammeter for measuring the charge / discharge current of the storage battery;
  A voltmeter for measuring a voltage between terminals of the storage battery;
  For multiple storage batteries with different battery capacities,The voltage across the terminals for each remaining capacity or percentage of charge,The discharge current of the storage battery is divided by a number indicating the full charge capacity of the storage battery.Memory means for storing a coefficient of a relational expression indicating a relation between current ratio values;
  A discharge state detection means for starting the following means when the storage battery detects a discharge state;
  Means for reading the discharge current of the storage battery measured with the ammeter, and the voltage across the terminals of the storage battery measured with the voltmeter;
  MeasuredDischarge current valueThe full charge capacity of the storage battery obtained in advanceWith a number indicatingA current ratio value calculating means for calculating a divided current ratio value;
  Using the coefficient of the relational expression stored in the memory means,Substituting the calculated current ratio value, the remaining capacity orState of chargeA terminal-to-terminal voltage calculating means for obtaining a terminal-to-terminal voltage with respect to the percentage of
  Comparing and comparing the obtained inter-terminal voltage and the measured inter-terminal voltage value, the remaining capacity of the storage battery orState of chargeA determination means for determining the percentage of
  Having
  A remaining capacity determination device for a storage battery mounted on a vehicle is provided.
[0023]
In the present invention, the inter-terminal voltage V and current I of the storage battery are measured, the current ratio value C obtained by dividing the current value I by the numerical value Q indicating the battery capacity Ah is calculated, and each remaining capacity or The terminal measured with the remaining capacity or the terminal voltage with respect to the percentage of SOC obtained by substituting the calculated current ratio value C into the relational expression between the terminal voltage with respect to the percentage of the state of charge (SOC) and the current ratio value. The remaining capacity is determined by comparing and contrasting the inter-voltage values.
[0024]
The current ratio value C represents a current value equal to the battery capacity at the time of full charge in a dimensionless amount of 1C.
For example, when the battery capacity when the storage battery is fully charged is 50 Ah, 1 C is 50 A. Moreover, the current ratio value of the charge / discharge current value 25A in the storage battery having a battery capacity of 50 Ah at full charge is 25/50 = 0.5C, and the charge / discharge current value 15A in the storage battery having a battery capacity of 30 Ah at full charge is The same current ratio value 15/30 = 0.5C which is the same as 0.5C. Thus, the magnitude of the current can be expressed by the ratio of the charge / discharge current value to the capacity of the storage battery at the time of full charge.
Accordingly, it is possible to determine the state of charge by applying the same relational expression of the current ratio values obtained in advance for each percentage of the state of charge for various lead storage batteries having different battery capacities.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
First embodiment
As a first embodiment of the present invention, a remaining capacity of a storage battery mounted on a vehicle having a so-called idling stop function that stops 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 idling stop and a method and apparatus for performing idling stop processing based on the determination result of the remaining capacity of the secondary storage battery such as a storage battery will be described.
[0026]
FIG. 1 shows a first embodiment of a method and apparatus for determining the remaining capacity of a storage battery mounted on a vehicle having an idling stop function according to the present invention, and a method and apparatus for performing idling stop processing based on the determination result. FIG.
A vehicle, for example, an ordinary passenger car, includes a starter 1, a generator (alternator) 2, a secondary storage battery 3, electrical equipment 4, and an engine 5.
As the secondary storage battery 3, a case where a lead storage battery is used will be described below.
The electric equipment 4 is a general term for electric loads mounted on vehicles that are electrically operated, such as various lights (lamps) such as illumination lamps, direction indicators, hazard lamps, mirror drive motors, operation panels, and air conditioners. .
[0027]
The starter 1 provides electric power for operating the engine 5 by power feeding from the lead storage battery 3 when the vehicle with the engine key turned on 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 electrical equipment 4 by the power generation of the alternator 2 accompanying the operation of the engine 5, the lead storage battery 3 is charged.
[0028]
An apparatus for determining the remaining capacity of a storage battery mounted on a vehicle having an idling stop function illustrated in FIG. 1 (hereinafter referred to as a remaining capacity determination apparatus for a storage battery) includes an ammeter 6 for measuring the current flowing through the lead storage battery 3, and It has the voltmeter 7 which measures the terminal voltage of the lead storage battery 3, the determination means 8 which determines the remaining capacity of the lead storage battery 3, and the display means 9 which displays a determination result.
The ammeter 6 is a normal DC ammeter that measures the current (discharge current and charge current) flowing through the lead storage battery 3, the sign − indicates the discharge current, and the sign + indicates the charge current.
The voltmeter 7 is a normal DC voltmeter that measures the terminal voltage of the lead storage battery 3.
The display means 9 is, for example, a liquid crystal display, and can also be used as a display for an operation panel portion of a normal passenger car.
[0029]
At the start of the vehicle in which the starter 1 is operated by the operation of the engine key, when the starter 1 starts the engine (internal combustion engine) 5, the alternator 2 operates to generate power. Thereafter, power supply to the electrical equipment 4 is performed from the alternator 2.
Since the alternator 2 operates and generates electric power while the vehicle in which the engine 5 is rotating and during idling, the lead storage battery 3 is charged by the generated voltage of the alternator 2. The voltage between the terminals of the lead storage battery 3 at this time matches the output voltage of the alternator 2. When an ordinary passenger car is exemplified as the vehicle, the output voltage of the alternator 2 is about 14.5V.
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.
When the vehicle is idling stopped by the operation of the idling stop processing means 10, the rotation of the engine 5 is stopped, so that the alternator 2 is also stopped and the power generation by the alternator 2 is stopped. At that time, power is supplied from the lead storage battery 3 to the electrical equipment 4 and the like. The voltage between the terminals of the lead storage battery 3 decreases due to power supply (discharge) from the lead storage battery 3 to the electrical equipment 4 or the like. The decrease in the voltage between the terminals of the lead storage battery 3 depends on the load current. The voltage between the terminals of the lead storage battery 3 when the lead storage battery 3 is opened and several hours or more have elapsed is about 12.9 V when the lead storage battery 3 in the charged state is fully charged. Therefore, the voltage between the terminals of the lead storage battery 3 when the load current is flowing is lower than 12.9V, and even when fully charged, it is lower than 12.9V, such as 12.5V. Sometimes. Thus, the decrease in the inter-terminal voltage of the lead storage battery 3 depends on the load current, in other words, the discharge current of the lead storage battery 3. Moreover, the fall of the voltage between the terminals of the lead storage battery 3 is also lowered by the remaining capacity or the state of charge (SOC).
[0030]
FIG. 2 is a diagram illustrating a configuration example of the determination unit 8.
The determination means 8 includes a central processing unit (CPU) 81 of a microcomputer, a memory 82 such as a RAM and a ROM, an analog / digital (A / D) conversion unit 83, and an input / output (I / O) port 84. A regulator 85, a display output interface (I / F) 86, a current measurement adjustment unit 87, and a voltage measurement adjustment unit 88.
The determination means 8 is a memory means, discharge state detection means, means for reading discharge current and terminal voltage, current ratio value calculation means, terminal voltage calculation means, storage battery remaining capacity or percentage of SOC of the present invention. Function as.
[0031]
The CPU 81 performs various processes described below. Hereinafter, the processing of the determination means 8 mainly means processing performed by the CPU 81. The CPU 81 functions as a discharge state detection means, a means for reading a discharge current and a terminal voltage, a current ratio value calculation means, a terminal voltage calculation means, a means for determining the remaining capacity of the storage battery or the percentage of SOC.
Various programs executed by the CPU 81 are stored in the ROM of the memory 82.
The RAM of the memory 82 stores relational expressions (coefficients thereof), which will be described later, and also stores measurement values of the ammeter 6, measurement values of the voltmeter 7, calculation processing data, and the like. Therefore, the RAM of the memory 82 corresponds to the memory means of the present invention. The RAM is preferably a rewritable nonvolatile memory so that the stored various data can be retained even during a vehicle stop period and new data can be written.
The A / D conversion unit 83 inputs the measurement results of the ammeter 6 and the voltmeter 7 expressed as analog voltage signals, and converts them into digital signals to be processed by the CPU 81.
The I / O port 84 has an input port for inputting a start signal and a restart signal for the digital engine 5 and an output port for outputting a digital signal indicating the determination result of the determination means 8 to the idling stop processing means 10 or the like. Have.
A display output interface (I / F) 86 is used for output to the display means 9.
[0032]
The regulator 85 inputs a power supply voltage applied in conjunction with the operation of the engine key of the engine 5 and adjusts the drive voltage to the CPU 81, the memory 82, the A / D converter 83, and the I / O port 84.
The CPU 81, the memory 82, the A / D converter 83, and the I / O port 84 that constitute the determination unit 8 are supplied with power from the alternator 2, the lead storage battery 3, and the like, but the CPU 81 normally operates at 3 to 5 VDC. However, since the voltages of the alternator 2 and the lead storage battery 3 drive various electric products mounted on the vehicle such as the electric equipment 4, the voltage is high such that the output voltage of the alternator 2 is about 14.5V, for example. Therefore, the regulator 85 adjusts such a high voltage to a voltage at which the CPU 81 or the like can operate.
[0033]
Since the input voltage range of the A / D conversion unit 83 is, for example, about 0 to ± 5 V, when the detected voltage is very low, such as when the ammeter 6 is used, the current measurement adjustment unit 87 sets the input voltage range to 0. Amplify to ~ 5V. Similarly, when the detected voltage of the voltmeter 7 is as high as about 0 to 15 V, the voltage measurement adjustment unit 88 divides the voltage to 0 to 5 V. When the level of the detection signal of the ammeter 6 and / or the detection signal of the voltmeter 7 is adjusted to the input voltage range of the A / D conversion unit 83 outside the determination means 8, the current measurement adjustment unit 87 and the voltage measurement The adjustment unit 88 is not necessary.
[0034]
When the idling stop processing means 10 is added to the storage battery remaining capacity determination device, the idling stop processing of the vehicle can be performed based on the result of the storage battery remaining capacity determination device.
As illustrated in FIG. 1, the configuration in which the idling stop processing means 10 is added to the storage battery remaining capacity determination device determines the remaining capacity of the storage battery mounted on the vehicle and has an idling stop processing function.
[0035]
Charging / discharging characteristics of lead acid battery 3
FIG. 3 shows the charging / discharging current waveforms of the storage battery when the lead-acid battery 3 is mounted, when starting (1) (when starting), during traveling (2), and when idling is stopped (3). The horizontal axis shows the passage of time, and the vertical axis shows the current. In addition, the charging current to the storage battery shown on the vertical axis is indicated by +, and the discharge current from the storage battery is indicated by-.
During the period {circle around (1)}, that is, when the engine 5 is started by rotating the engine key, a large discharge current (−) flows from the lead storage battery 3 to the starter 1 to operate the starter 1 that operates the engine 5.
During the period {circle around (2)}, that is, while the vehicle is running after the vehicle is started, the engine 5 is operated and the alternator 2 is operated, so that the electric equipment 4 from the generator (alternator) 2 is supplied with power, The charging current flows through the lead storage battery 3 and the lead storage battery 3 is charged.
During the period {circle around (3)}, that is, when the idling stop processing means 10 determines that idling is possible and the engine 5 is stopped, the alternator 2 is also stopped because the engine 5 is stopped. A discharge current (negative flat curve) flows.
[0036]
The charging / discharging state of the lead storage battery 3 during the period (1) to (3) described above is simplified and illustrated as (4) to (6).
During period {circle around (4)}, the starter 1 is started in order to restart the engine 5 after the end of the idling stop between the end of {circle around (3)} and the beginning of {circle around (4)}. A large discharge current flows from the lead storage battery 3 to the starter 1 (−). Of course, power supply from the lead storage battery 3 to the electrical equipment 4 is also performed.
When the engine 5 is restarted and the alternator 2 is operated, the lead storage battery 3 is charged by the alternator 2 (+ charging current) as in the case of the rising edge of (2).
In the idling stop state, a discharge current flows from the lead storage battery 3 to the electrical equipment 4 or the like (a discharge current having a constant value of −).
After the idling stop between {circle over (4)} and {circle over (5)} is completed, the starter 1 is started, so that a discharge current flows from the lead storage battery 3 to the starter 1.
[0037]
The period {circle around (5)} is the same as the period {circle around (4)}, but during the period {circle around (5)}, the traveling period is long and the idling stop time is short.
[0038]
The discharge current or charging current of the lead storage battery 3 can be measured with an ammeter 6, and the terminal voltage of the lead storage battery 3 can be measured with a voltmeter 7. The determination means 8, particularly the CPU 81, reads the measurement values of the ammeter 6 and the voltmeter 7 and determines the remaining capacity and SOC of the lead storage battery 3 with reference to those measurement values.
[0039]
Hereinafter, the charging state determination process for the lead acid battery for the vehicle in the storage battery remaining capacity determination device illustrated in FIGS. 1 and 2 will be described.
[0040]
SOC determination processing
While the vehicle is traveling during the period {circle around (2)} in FIG. 3, charging current often flows from the alternator 2 to the lead storage battery 3.
While idling is stopped during the period {circle around (3)}, since the engine 5 is stopped, the alternator 2 does not generate power and the lead storage battery 3 is not charged. Charging current flows to the electrical load.
The idling stop is shifted to the idling stop when it is determined by the idling stop processing means 10 that the idling stop is possible, particularly when it is determined that the remaining capacity of the lead storage battery 3 is idling stopped and can be restarted. To do.
[0041]
The details of the determination method of the remaining capacity of the lead storage battery 3 during idling stop performed by the determination means 8 will be described with reference to the flowchart of FIG.
[0042]
Step 1: As pre-processing, the operator determines the relational expression (see FIG. 5) between the terminal voltage V and the current ratio value C with respect to the percentage of each remaining capacity or SOC determined in advance as illustrated in FIG. Is stored in the RAM of the memory 82.
The relational expression illustrated in FIG. 5 can be approximated by a linear line as shown in Expression 1 to be described later. Therefore, the coefficient a of each straight line is stored in the RAM of the memory 82._Qn, B_QnShould be memorized.
The contents of this relational expression and how to obtain it (measurement method) will be described later.
[0043]
Step 2: The determination means 8 (CPU 81) performs the following processing continuously when I <set discharge current value is satisfied. If not, the remaining capacity is calculated by the current integration method.
(1) Step 3: The CPU 81 measures the discharge current flowing from the lead storage battery 3 with the ammeter 6 and simultaneously measures the voltage between the terminals of the lead storage battery 3 with the voltmeter 7.
(2) Step 4: A current ratio value C (= I / Q) obtained by dividing the discharge current value I measured by the ammeter 6 by the numerical value Q (Ah) indicating the full charge capacity of the lead storage battery 3 is calculated.
(3) Step 5: The determination means 8 calculates in Step 4 the relational expression of the inter-terminal voltage V and the current ratio value C with respect to each remaining capacity or SOC percentage of the lead storage battery 3 obtained in advance in Step 1. By substituting the current ratio value C, the terminal-to-terminal voltage with respect to the remaining capacity of the lead storage battery 3 or the percentage of SOC is obtained.
(4) Step 6: The CPU 81 determines the state of charge or the SOC of the lead storage battery 3 by comparing and comparing the terminal voltage obtained in Step 5 with the inter-terminal voltage value measured by the voltmeter 7.
(5) Step 7: The CPU 81 repeats the processes of Steps 2 to 6 until the driving of the vehicle is completed.
[0044]
Details of remaining capacity or SOC calculation method
FIG. 5 is a graph showing data used when calculating the remaining capacity or the SOC from the measured values of the discharge current from the lead storage battery 3 and the voltage between the terminals of the lead storage battery 3. Details of the plot in the figure will be described later. The vertical axis represents the voltage between the terminals of the lead storage battery 3, and the horizontal axis represents the ratio of the current value I to the full charge capacity Q (Ah) of the lead storage battery 3, that is, the current ratio value C (= I / Q).
From the illustration of FIG. 5, it can be seen that when the current ratio value C increases, that is, when the discharge current of the lead storage battery 3 increases, the voltage between the terminals of the lead storage battery 3 decreases. And it turns out that the relationship between the current ratio value C (discharge current I) of the lead storage battery 3 and the voltage V between terminals has linearity (linear relationship). Therefore, each remaining capacity Q in FIG.₁ ~ Q₉ Terminal voltage V to be calculated in_n And the current ratio value C are expressed by the following linear expression.
[0045]
[Equation 3]
V_Qn= A_Qn× C + b_Qn
However, a_QnIs the remaining capacity Q_n The first coefficient in
b_QnIs the remaining capacity Q_n Is the second coefficient.
... (1)
[0046]
In step 1 of FIG. 4, the coefficient a of the linear equation is used as a relational expression stored in the RAM of the memory 82._Qn, B_QnRemember.
In step 6 of FIG. 4, to determine the current remaining capacity or SOC level of the lead storage battery 3 using the data illustrated in FIG. 5, the ammeter 6 is measured according to the relational expression shown in equation 1. Substituting the current ratio value C obtained in step 4 from the current value to obtain the voltage value V between terminals of each remaining capacity or each SOC (step 5), the calculated inter-terminal voltage and the terminal actually measured by the voltmeter 7 The level of the remaining capacity of the lead storage battery 3 can be determined by comparing the voltage between the two. That is, since the terminal voltage of the lead storage battery 3 indicates the remaining capacity, the remaining capacity of the lead storage battery 3 is estimated by comparing the calculated terminal voltage with the terminal voltage actually measured by the voltmeter 7. can do.
[0047]
Estimating remaining capacity
Furthermore, when estimating (estimating) the value of the remaining capacity or SOC of the lead storage battery 3, it can be calculated using the following formula as an approximate value.
The following formula 2 shows the discharge current value and the terminal voltage value V of the lead storage battery 3 when the current remaining capacity of the lead storage battery 3 is Qn._QnIs a linear expression representing the relationship.
Equation 3 below indicates that the previous remaining capacity of the lead storage battery 3 is Q_{n + 1} Discharge current value and inter-terminal voltage value V of the lead storage battery 3 at the time of_{Qn + 1}Is a linear expression representing the relationship.
V_Qn, V_{Qn + 1}Is the remaining capacity Q_n , Remaining capacity Q_{n + 1} It is the voltage value between terminals calculated from the measured discharge current value of the storage battery at. Here, (Q_n<Q_{n + 1} ).
α, β, γ, and δ are coefficients, respectively, and C is a current ratio value.
The coefficients α, β, γ, and δ are stored in the RAM of the memory 82 of the determination unit 8.
The current ratio value C is defined by C = (measured current (A) of the lead storage battery 3) / (capacity Q (Ah) when the lead storage battery 3 is fully charged).
[0048]
[Expression 4]
V_Qn= Α × C + β (2)
[0049]
[Equation 5]
V_{Qn + 1}= Γ × C + δ (3)
[0050]
Expression 4 is an expression for obtaining the remaining capacity of the lead storage battery 3.
V is the voltage between the terminals of the lead storage battery 3 measured by the voltmeter 7.
[0051]
[Formula 6]
Remaining capacity = Q_n + (Q_{n + 1} -Q_n ) X [(V-V_Qn) / (V_{Qn + 1}-V_Qn)]
However, Q_n , Q_{n + 1} Is the remaining capacity,
Q_n <Q_{n + 1} And
V_QnIs the remaining capacity Q_n Is the terminal voltage calculated from the measured discharge current value of the storage battery at
V_{Qn + 1}Is the remaining capacity Q_{n + 1} It is the voltage between terminals calculated from the measured discharge current value of the storage battery.
(4)
[0052]
If the formulas 1 to 4 are used, the determination means 8 (CPU 81) can calculate the remaining capacity of the lead storage battery 3 or the percentage of SOC.
[0053]
A specific example of a method for determining the remaining capacity or SOC when the lead storage battery 3 is discharged will be described.
For example, when the discharge current value I of the lead storage battery 3 is 12.5 A, the voltage value V between terminals is V = 24.2 V, and the battery capacity Q at full charge of the lead storage battery 3 mounted on the vehicle is 50 Ah, the current ratio value C becomes (12.5 / 50 =) 0.25C from C = (measured current (A) of the lead storage battery 3) / (capacity Q (Ah) at the time of full charge of the lead storage battery 3) in FIG. The horizontal axis terminal voltage V = 24.2 V and the horizontal axis current ratio value C = 0.25 can be plotted as an intersection (portion indicated by a black circle).
The remaining capacity of the portion located above and below the plotted intersection is expressed as the remaining capacity Q_Five= 25Ah, Q₆= 30 Ah, the remaining capacity at the plotted intersection is 25 Ah or more and 30 Ah or less.
[0054]
The current ratio value C and the inter-terminal voltage V of the storage battery in each remaining capacity or each SOC in FIG._Five, V₆The relationship of V = V is obtained by applying α = −2.12, β = + 24.58_Five= −2.12C + 24.58, γ = −2.20, δ = + 24.84₆= −2.20C + 24.84, so the remaining capacity Q at the current ratio value C = 0.25C._Five, Q₆The voltage value at V is V_Five= 24.05, V₆= 24.29.
Therefore, when the CPU 81 of the determination means 8 performs the interpolation process, the remaining capacity is 25+ (30-25) × [(24.2-24.05) / (24.29-24.05)] = 28.13 Ah. Can be obtained as
[0055]
Further, the CPU 81 of the determination means 8 may calculate the percentage of SOC = 56.3% by dividing the remaining capacity 28.13 Ah obtained as described above by the battery capacity Q = 50 Ah when the lead storage battery 3 is fully charged. .
[0056]
How to create the relationship between terminal voltage and current ratio
With reference to FIG. 6, a method of creating the relational expression between the voltage between terminals and the current ratio value shown in FIG. FIG. 6 is a graph obtained by actually measuring the terminal voltage of the lead storage battery 3 when discharged.
(1) For example, in the case of a lead storage battery 3 with a fully charged battery capacity of 50 Ah, the lead storage battery 3 is set to a fully charged state, and as shown in FIG. 6, the current ratio value C1 converted to C is set to T11 time (T11 seconds). ), The current ratio values C2 and C3 were each discharged continuously for T12 hours (T12 seconds) and the current ratio values C4 were continuously discharged for T13 hours (T13 seconds), and the voltage between the terminals of the storage battery at that time was measured with a voltmeter 7 .
(2) Next, constant current discharge was performed for T21 hours (T21 seconds) at the current ratio value C5 converted to the current ratio value C in order to adjust the remaining capacity or SOC of the lead storage battery 3.
(3) Thereafter, the current ratio value C1 is continuously discharged for T11 seconds, the current ratio values C2 and C3 are each continuously discharged for T12 seconds, and the current ratio value C4 is continuously discharged for T13 seconds. Was measured with a voltmeter 7.
(4) Again, in order to adjust the remaining capacity of the lead storage battery 3, constant current discharge is carried out at the current ratio value C5 for T21 hours, the current ratio value C1 is set to T11 seconds, the current ratio values C2 and C3 are set to T12 seconds, respectively. The current ratio value C4 was continuously discharged for T13 seconds, and the voltage between the terminals of the lead storage battery 3 at that time was repeatedly measured with the voltmeter 7 and discharged until the battery capacity of the lead storage battery 3 was exhausted. . The determination of the condition that the battery capacity runs out was made when the terminal voltage dropped to 10.5 V when a 12 V car battery was used as the lead storage battery 3.
[0057]
Referring to FIG. 6, the actually measured voltage between the terminals starts to discharge from the storage battery at the current ratio value current C1 and starts to discharge at the T11 second voltage, and similarly starts to discharge at the current ratio value currents C2 and C3, and at the T12 second voltage. This is the voltage value at T13 seconds after starting to discharge at the current ratio value current C4.
Thus, by measuring the voltage between terminals when the current ratio value in each remaining capacity of the storage battery is changed, the relational expression between the terminal voltage and the current ratio value illustrated in FIG. 5 can be created.
[0058]
As another method for obtaining the relational expression illustrated in FIG. 5, each current ratio value C is discharged to 10.5 V which is a determination condition that the battery capacity of the lead storage battery 3 is lost, and then the current ratio value 0.2C. The battery voltage may be obtained by discharging the battery and the capacity obtained by subtracting the discharge capacity from the total is used as each remaining capacity.
[0059]
Sharing of relational expression between terminal voltage and current ratio value
When determining the remaining capacity or SOC of the lead storage battery 3, by measuring the current integration method described above, the discharge current value from the storage battery and the inter-terminal voltage value, and referring to the relational expression between the inter-terminal voltage and the discharge current value There are two methods: a calculation method.
7A and 7B show the relationship between current and voltage of storage batteries having different battery capacities when fully charged. In FIG. 7A, the horizontal axis is the discharge current value, and in FIG. 7B, the horizontal axis is the current ratio value. Both vertical axes represent the voltage between terminals.
As illustrated in FIG. 7B, by changing the horizontal axis from the current value illustrated in FIG. 7A to the current ratio value, even with batteries having different battery capacities at full charge, the voltage between terminals and the current ratio value are The relationship between the currents shown is that the characteristics shown by the solid line and the characteristics shown by the broken line are almost the same and are almost the same. This is because the characteristics of the voltage between the terminals at the time of discharging become substantially the same by discharging with a current having a current ratio value corresponding to the battery capacity at the time of full charge. Therefore, even in storage batteries having different battery capacities when fully charged, it is possible to determine the remaining capacity or SOC of the lead storage battery 3 using the same data.
[0060]
Thus, according to 1st Embodiment of this invention, when determining the charge condition of the storage battery mounted in the vehicle, the current from the storage battery and the voltage between terminals were measured and prepared in advance. The remaining capacity is determined by comparing and comparing the voltage between terminals and the current ratio value for each remaining capacity, and the current ratio value is used in the relational expression used for determining the remaining capacity. Since it is possible to respond by preparing only one type of relationship between terminal voltage and current ratio value that covers storage batteries with different battery capacities, it is only necessary to measure the relationship between terminal voltage and current ratio value for each storage battery manufacturer. Can respond.
[0061]
Furthermore, it is possible to apply almost the same equipment for each type of storage battery that is applied to ordinary cars, light automatics, large buses and large trucks having an idling stop function. Can be significantly reduced.
[0062]
In the said embodiment, although the lead storage battery 3 was illustrated as the secondary storage battery 3, if it is the secondary storage battery 3 in the case of application of this invention, it will not be limited to a lead storage battery. However, it is necessary to change the characteristic data such as the threshold value described above according to the selected secondary storage battery.
[0063]
Second embodiment
The idling stop processing means 10 can supply power from the lead storage battery 3 to the electrical equipment 4 while the remaining capacity of the lead storage battery 3 calculated by the above-described method is in the idling stop. Further, after the idling stop is completed, the lead storage battery When it is determined that there is a sufficient remaining capacity capable of supplying power to the starter 1 from 3 to drive the starter 1, the vehicle enters the idling stop state, for example, when the vehicle is continuously stopped for a predetermined time.
[0064]
The idling stop processing means 10 monitors whether the remaining capacity of the lead storage battery 3 is updated by the above-described method during idling stop, and determines whether or not the idling stop state can be continued.
For example, the idling stop processing means 10 before the occurrence of a situation in which the idling stop period is long and the remaining capacity of the lead storage battery 3 is insufficient to restart the starter 1 due to power supply to the electrical equipment 4 occurs. Ends the idling stop and starts the starter 1.
[0065]
According to the first embodiment of the present invention, since the remaining capacity or SOC of the lead storage battery 3 is accurately measured, the idling stop process can also be accurately performed.
[0066]
【The invention's effect】
According to the method and apparatus for determining the remaining capacity of a storage battery mounted on a vehicle having an idling stop function of the present invention, it is a simple configuration or processing method, is easy to implement, and is suitable for practical use.
[0067]
In addition, according to the method and apparatus for determining the remaining capacity of a storage battery mounted on a vehicle having an idling stop function according to the present invention, it is possible to perform idling stop processing with high reliability.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an embodiment of an apparatus for determining a remaining capacity of a storage battery mounted on a vehicle having an idling stop function according to the present invention.
FIG. 2 is a diagram illustrating a specific example of the apparatus configuration illustrated in FIG. 1;
FIG. 3 is a graph showing an example of a current waveform of the storage battery during running and idling stop.
FIG. 4 is a flowchart showing a processing method in the CPU of the determination means for determining the remaining capacity or SOC of the lead storage battery during idling stop.
FIG. 5 is a graph showing a relational expression between a terminal voltage and a current ratio value of the storage battery used when calculating the remaining capacity or SOC of the lead storage battery.
FIG. 6 is a graph obtained by actually measuring the voltage between the terminals of the lead storage battery 3 when discharged.
FIGS. 7A and 7B are graphs showing the relationship between the current and voltage of storage batteries having different battery capacities when fully charged, and FIG. 7A shows the discharge current value on the horizontal axis; FIG. 7B is a graph with the horizontal axis representing the current ratio value.
[Explanation of symbols]
1. Starter 2. Alternator 3. Secondary storage battery (lead storage battery)
4 .... Electric equipment, 5 .... Engine, 6 .... Ammeter, 7 .... Voltmeter
8 .. Judgment means
81..CPU, 82..Memory, 83..A / D converter
84..I / O port, 85..Regulator,
86 .. Display output interface (I / F),
87 .. Current measurement adjustment unit, 88 .. Voltage measurement adjustment unit
9 .. Display means 10.. Idling stop processing means

Claims

A method for determining a remaining capacity of a storage battery mounted on a vehicle,
For a plurality of storage batteries having different battery capacities, the relationship between the terminal voltage with respect to the percentage of each remaining capacity or charge state and the current ratio value obtained by dividing the discharge current of the storage battery by the number indicating the full charge capacity of the storage battery is shown. Find the relational expression in advance,
When the storage battery is discharged,
Measure the inter-terminal voltage and discharge current of the storage battery,
Calculate a current ratio value obtained by dividing the value of the measured discharge current by a number indicating the full charge capacity of the storage battery obtained in advance,
Said pre-determined, the relational expression showing the relation between terminal voltage and the current ratio value for the percentage of each remaining capacity or state of charge of the battery, the residual capacity or charge by substituting the current ratio value the calculated Find the voltage across the terminals for the percentage of the state ,
A method for determining a remaining capacity of a storage battery or a percentage of a charged state by comparing and comparing the obtained inter-terminal voltage and the measured inter-terminal voltage value.

Current ratio value (C) obtained by dividing the inter-terminal voltage (V _Qn ) with respect to the percentage of each remaining capacity (Q _n ) or state of charge (SOC) and the discharge current of the storage battery by the number indicating the full charge capacity of the storage battery The relational expression showing the relation is defined by the following formula:
V _Qn = a _Qn × C + b _Qn
However, a _Qn and b _Qn are coefficients obtained in advance.
A method for determining a remaining capacity of a storage battery mounted on a vehicle according to claim 1.

In the step of obtaining in advance a relational expression between the terminal voltage (V _Qn ) and the current ratio value (C) for each remaining capacity (Q _n ) of the storage battery,
With respect to a storage battery having a battery capacity that is larger than any of the remaining capacity (Q _n ) when fully charged, first, when the storage battery is fully charged, currents of a plurality of first current ratio values that are constant are extremely small. A first measurement step of discharging only for a short time and measuring the voltage between the terminals at this time;
The process of adjusting the discharge capacity by continuing the discharge at a constant second current ratio value for an arbitrary time is repeated until the voltage drops to a predetermined inter-terminal voltage,
First discharge capacity is defined by the product of the current (Id2) of the second current rate value discharged total time of time (T2) of said constant at a constant second current fraction value of the current (Id2) When the discharge capacity is discharged at each constant of the first measurement step is a sum of the products of the plurality of first current ratio value (Id1) and very short time (T1), said first measuring step By the second discharge capacity defined by the product of the number of times (n) performed, the total third discharge capacity is defined as the total discharge capacity of the storage battery,
And before carrying out said repeatedly performed each of the first measuring step, the total amount of the discharge capacity to be discharged by the second discharge capacity by the current ratio value of the current and of the first measuring step, the total discharge of the battery For each discharge capacity subtracted from the capacity, the first characteristic is obtained and the first characteristic is represented by an approximate expression, and the relational expression between the voltage between terminals and the current ratio value is obtained.
A method for determining a remaining capacity of a storage battery mounted on a vehicle according to claim 2 .

As a condition when the storage battery is discharging, the condition is when the vehicle is idling stop and discharging from the storage battery,
Remaining capacity determination method of a storage battery mounted on the vehicle according to claim 1.

When the idling is stopped, the remaining capacity of the storage battery is calculated based on the following formula:
The remaining capacity determination method of the storage battery mounted in the vehicle of Claim 4 .
[Expression 1]
Remaining capacity = Q _n + [(Q _n-1 −Q _n ) × (V−V _Qn )] / (V _Qn−1 −V _Qn )
Where Q _n is the current remaining capacity,
Q _n-1 is the previous remaining capacity,
V _Qn is a voltage between terminals calculated from the measured discharge current value of the storage battery at the remaining capacity Q _n , and is a voltage represented by the following formula:
V _Qn = α × C + β
Where α and β are coefficients,
C is the current ratio value (measured discharge current value / battery capacity at full charge)
V _Qn-1 is a voltage between terminals calculated from the measured discharge current value of the storage battery at the remaining capacity Q _n-1 , and is a voltage represented by the following equation:
V _Qn-1 = γxC + δ
Where γ and δ are coefficients,
C is the current ratio value (measured discharge current value / battery capacity at full charge)
V is the measured inter-terminal voltage of the storage battery.

When the vehicle is traveling, and calculates the remaining capacity of the electric storage battery by integrating charging current measured by the current meter,
Sum the remaining capacity obtained when the storage battery is discharging,
A method for determining a remaining capacity of a storage battery mounted on a vehicle according to claim 1 .

When starting or starting the vehicle, a predetermined amount of discharge is subtracted from the remaining capacity of the storage battery,
The remaining capacity determination method of the storage battery mounted in the vehicle in any one of Claims 1-6 .

When the determined remaining capacity is a predetermined amount or more, an idling stop is performed.
The remaining capacity determination method of the storage battery mounted in the vehicle in any one of Claims 1-7 .

A starter for starting the engine, an alternator operated by the engine, electrical equipment, and supplying power to the starter and the electrical equipment at the time of starting or restarting the vehicle, and charging from the alternator when the vehicle is running, the vehicle is idling stop A storage battery remaining capacity determination device equipped with a storage battery for supplying power to the electrical equipment at the time,
An ammeter for measuring the charge / discharge current of the storage battery;
A voltmeter for measuring a voltage between terminals of the storage battery;
For a plurality of storage batteries having different battery capacities, the relationship between the terminal voltage with respect to the percentage of each remaining capacity or charge state and the current ratio value obtained by dividing the discharge current of the storage battery by the number indicating the full charge capacity of the storage battery is shown. Memory means for storing coefficients of relational expressions;
A discharge state detection means for starting the following means when the storage battery detects a discharge state;
Means for reading the discharge current of the storage battery measured with the ammeter, and the voltage across the terminals of the storage battery measured with the voltmeter;
A current ratio value calculating means for calculating a current ratio value obtained by dividing the value of the measured discharge current by a number indicating the full charge capacity of the storage battery obtained in advance;
An inter-terminal voltage calculating means for substituting the calculated current ratio value into the relational expression using the coefficient of the relational expression stored in the memory means to obtain a terminal-to-terminal voltage with respect to a remaining capacity or a percentage of a charged state ; ,
A judgment means for comparing and comparing the obtained inter-terminal voltage and the measured inter-terminal voltage value to determine a remaining capacity or a charged state percentage of the storage battery,
An apparatus for determining a remaining capacity of a storage battery mounted on a vehicle.