JP3817141B2

JP3817141B2 - Deterioration degree determination method and apparatus for vehicle battery

Info

Publication number: JP3817141B2
Application number: JP2001046857A
Authority: JP
Inventors: 英明蒲原; 智博川口; 倫人榎本; 洋一荒井
Original assignee: Yazaki Corp
Current assignee: Yazaki Corp
Priority date: 2000-12-05
Filing date: 2001-02-22
Publication date: 2006-08-30
Anticipated expiration: 2021-02-22
Also published as: JP2002236156A

Description

【０００１】
【発明の属する技術分野】
本発明は、車両に搭載されている負荷に電力を供給するため車両に搭載されたバッテリの劣化度を判定する車両用バッテリの劣化度判定方法及び装置に関するものである。
【０００２】
【従来の技術】
従来、車両使用中のバッテリの劣化度を判定するには、車両用鉛バッテリの場合、エンジンの始動性が悪くなったこと、また電気車両用バッテリの場合、走行距離が短くなったことなどにより、人の感覚に頼って判断することが一般に行われていた。
【０００３】
【発明が解決しようとする課題】
しかしながら、人の感覚に頼って判断することは信頼性に乏しく、しばしば判断を誤り、バッテリ上がりを生じてしまうことがあった。
【０００４】
よって、本発明は上述した状況に鑑み、車両使用中のバッテリの劣化度を判定することのできる車両用バッテリの劣化度判定方法及び装置を提供することを課題としている。
【０００５】
【課題を解決するための手段】
前記目的を達成する請求項１乃至請求項９記載の本発明は、車両用バッテリの劣化度判定方法に、請求項１０乃至請求項１８記載の本発明は、車両用バッテリの劣化度判定装置にそれぞれ関し、いずれの発明も、バッテリの純抵抗がバッテリの劣化度に応じて変化することに着目してなされたものである。
【０００６】
上記課題を解決するためなされた請求項１記載の発明は、車両に搭載されている負荷に電力を供給するため車両に搭載されたバッテリの劣化度を判定する車両用バッテリの劣化度判定方法において、前記搭載されたバッテリに相当するバッテリの未使用時における充電状態に対応するバッテリの純抵抗と寿命時における充電状態に対応するバッテリの純抵抗とをそれぞれ予め定めておき、前記搭載されたバッテリから前記負荷に所定値を越えて単調増大し最大値から所定値以下に単調減少する放電電流が流れたとき周期的に測定して得た前記バッテリの端子電圧と放電電流とに基づいて、前記搭載されたバッテリの純抵抗を測定し、該測定した純抵抗と、該純抵抗を測定したときの前記搭載されたバッテリの充電状態に対応する前記予め定めた未使用時における純抵抗及び前記予め定めた寿命時における純抵抗とに基づいて、前記搭載されたバッテリの劣化度を算出し判定することを特徴とする車両用バッテリの劣化度判定方法に存する。
【０００７】
上述した請求項１記載の手順によれば、まず搭載されたバッテリに相当するバッテリの未使用時における充電状態に対応するバッテリの純抵抗と寿命時における充電状態に対応するバッテリの純抵抗とをそれぞれ予め定めておき、車両に搭載されているバッテリから負荷に所定値を越えて単調増大し最大値から所定値以下に単調減少する放電電流が流れたとき周期的に測定して得た車両に搭載されたバッテリの端子電圧と放電電流とに基づいてバッテリの純抵抗を測定する。次に、測定した純抵抗と、該純抵抗を測定したときの搭載されたバッテリの充電状態に対応する予め定めた未使用時における純抵抗及び予め定めた寿命時における純抵抗とに基づいて、搭載されたバッテリの劣化度を算出し判定しているので、車両使用状態において、搭載されたバッテリの劣化度を自動的に判定することができる。
【０００８】
請求項２記載の発明は、請求項１記載の車両用バッテリの劣化度判定方法において、前記劣化度を、前記測定した純抵抗と前記未使用時の純抵抗との差を、前記寿命時の純抵抗と前記未使用時の純抵抗との差で除した値の百分率によって求めることを特徴とする車両用バッテリの劣化度判定方法に存する。
【０００９】
上述した請求項２記載の手順によれば、劣化度を、百分率によって求めているので、劣化の進行具合を具体的な数値によって客観的に把握できる。
【００１０】
請求項３記載の発明は、請求項１又は２に記載の車両用バッテリの劣化度判定方法において、前記負荷に所定値を越えて単調増大し最大値から所定値以下に単調減少する放電電流が流れたときの前記バッテリの端子電圧と放電電流とを周期的に測定してこれら端子電圧と放電電流との相関を示す前記増大する放電電流に対する電圧−電流特性の第１の近似曲線式と前記減少する放電電流に対する電圧−電流特性の第２の近似曲線式とを求め、前記第１の近似曲線式によって表される電圧−電流特性曲線上に第１の点を、前記第２の近似曲線式によって表される電圧−電流特性曲線上に第２の点をそれぞれ定め、前記第２の点に対応する第２の放電電流が流れたとき第２の電圧降下を生じさせる、バッテリの純抵抗と第２の分極抵抗成分からなる第２の合成抵抗と同一の抵抗値を有する第１の想定点を前記第１の近似曲線式によって表される電圧−電流特性曲線上に、前記第１の点に対応する第１の放電電流が流れたとき第１の電圧降下を生じさせる、バッテリの純抵抗と第１の分極抵抗成分からなる第１の合成抵抗と同一の抵抗値を有する第２の想定点を前記第２の近似曲線式によって表される電圧−電流特性曲線上にそれぞれ想定し、前記第２の点と前記第１の想定点とを結ぶ直線の第１の傾斜を、前記第２の放電電流と前記第１の想定点での放電電流とによってそれぞれ生じる、前記第２の分極抵抗成分による電圧降下の差分を補正した上で、前記第２の分極抵抗成分による電圧降下分を除いた第１の補正傾斜を求めるとともに、前記第１の点と前記第２の想定点とを結ぶ直線の第２の傾斜を、前記第１の放電電流と前記第２の想定点での放電電流とによってそれぞれ生じる、前記第１の分極抵抗成分による電圧降下の差分を補正した上で、第１の分極抵抗成分による電圧降下分を除いた第２の補正傾斜を求め、該求めた前記第１及び第２の傾斜を加算平均して平均傾斜を求め、該求めた平均傾斜を前記バッテリの前記純抵抗として測定することを特徴とする車両用バッテリの劣化度判定方法に存する。
【００１１】
上述した請求項３記載の手順によれば、車両用バッテリの劣化度を判定するために使用するバッテリの純抵抗の測定方法に特徴を有し、車両の負荷にバッテリから電力が供給され、車両の負荷に所定値を越えて単調増大し最大値から所定値以下に単調減少する放電電流が流れたときのバッテリの端子電圧と放電電流とを周期的に測定してこれら端子電圧と放電電流との相関を示す増大する放電電流に対する電圧−電流特性の第１の近似曲線式と減少する放電電流に対する電圧−電流特性の第２の近似曲線式とを求める。
【００１２】
次に、第１の近似曲線式によって表される電圧−電流特性曲線上に第１の点を、第２の近似曲線式によって表される電圧−電流特性曲線上に第２の点をそれぞれ定める。そして、第２の点に対応する第２の放電電流が流れたとき第２の電圧降下を生じさせる、バッテリの純抵抗と第２の分極抵抗成分からなる第２の合成抵抗と同一の抵抗値を有する第１の想定点を前記第１の近似曲線式によって表される電圧−電流特性曲線上に、第１の点に対応する第１の放電電流が流れたとき第１の電圧降下を生じさせる、バッテリの純抵抗と第１の分極抵抗成分からなる第１の合成抵抗と同一の抵抗値を有する第２の想定点を前記第２の近似曲線式によって表される電圧−電流特性曲線上にそれぞれ想定する。
【００１３】
その後、第２の点と第１の想定点とを結ぶ直線の第１の傾斜を、第２の放電電流と第１の想定点での放電電流とによってそれぞれ生じる、第２の分極抵抗成分による電圧降下の差分を補正した上で、第２の分極抵抗成分による電圧降下分を除いた第１の補正傾斜を求めるとともに、第１の点と前記第２の想定点とを結ぶ直線の第２の傾斜を、第１の放電電流と第２の想定点での放電電流とによってそれぞれ生じる、第１の分極抵抗成分による電圧降下の差分を補正した上で、第１の分極抵抗成による電圧降下分を除いた第２の補正傾斜を求める。
【００１４】
このようにして求めた第１及び第２の傾斜を加算平均して平均傾斜を求め、該求めた平均傾斜をバッテリの純抵抗として測定している。したがって、車両の通常の使用状態で負荷に電力を供給したときのバッテリの端子電圧と放電電流とを測定し、この測定の結果得られるデータを処理するだけで、バッテリの純抵抗を測定することができる。
【００１５】
請求項４記載の発明は、請求項３記載の車両用バッテリの劣化度判定方法において、前記第１の点と前記第２の点とを、前記第１の近似曲線式と前記第２の近似曲線式を求めるため測定した前記バッテリの端子電圧と放電電流の存在する範囲内に定めることを特徴とする車両用バッテリの劣化度判定方法に存する。
【００１６】
上述した請求項５記載の手順によれば、第１の点と第２の点とを、第１の近似曲線式と第２の近似曲線式を求めるため測定したバッテリの端子電圧と放電電流の存在する範囲内に定めているので、傾斜を求めるための少なくとも一方が実データに基づくものとなり、実際から大きく外れた点を使用することをなくすることができる。
【００１７】
請求項５記載の発明は、請求項３又は４記載の車両用バッテリの劣化度判定方法において、前記第１の近似曲線式と前記第２の近似曲線式とを求めるに当たって、周期的に測定した前記バッテリの端子電圧と放電電流とを最新の所定時間分収集して格納、記憶しておくことを特徴とする車両用バッテリの劣化度判定方法に存する。
【００１８】
上述した請求項５記載の手順によれば、第１の近似曲線式と第２の近似曲線式とを求めるに当たって、周期的に測定したバッテリの端子電圧と放電電流とを最新の所定時間分収集して格納、記憶しているので、この記憶した実データを用いて、第１の近似曲線式と第２の近似曲線式とを求めるに必要な放電電流が流れたことを確認してから、記憶してある実データを用いて第１の近似曲線式と第２の近似曲線式とを求めることができる。
【００１９】
請求項６記載の発明は、請求項１又は２に記載の車両用バッテリの劣化度判定方法において、前記負荷に放電電流が流れたときの前記バッテリの端子電圧と放電電流とを周期的に測定して得、所定期間に所定値以上に急激に増大する放電電流が流れたときの前記測定によって得られた端子電圧と放電電流に基づいて、前記端子電圧と放電電流との単位時間当たりの変化量を求め、該求めた端子電圧の変化量を放電電流の変化量により除して求めた値をバッテリの純抵抗として測定することを特徴とする車両用バッテリの劣化度判定方法に存する。
【００２０】
上述した請求項６記載の手順によれば、所定期間に所定値以上に急激に増大する放電電流が流れたときの端子電圧と放電電流に基づいて、端子電圧と放電電流との単位時間当たりの変化量を求めているので、この単位時間に増大した放電電流によって発生する分極は非常に小さく、端子電圧の変化量、すなわち、電圧降下に分極抵抗成分の占める割合が極めて小さく、実質的に純抵抗によるものとみなすことができ、よって、端子電圧の変化量を放電電流の変化量により除して求めた値はバッテリの純抵抗を表すとすることができる。
【００２１】
請求項７記載の発明は、請求項６記載の車両用バッテリの劣化度判定方法において、前記端子電圧と放電電流との単位時間当たりの変化量を求めるに当たって、前記放電電流が所定期間に所定値以上増大するものであることを検出することを特徴とする車両用バッテリの劣化度判定方法に存する。
【００２２】
上述した請求項７記載の手順によれば、端子電圧と放電電流との単位時間当たりの変化量を求めるに当たって、放電電流が所定期間に所定値以上増大するものであることを検出していて、放電電流が所定期間に所定値以上増大するものでないときには、単位時間当たりの変化量を求めることがないので、測定した純抵抗の精度を常に所定範囲内のものとすることができる。
【００２３】
請求項８記載の発明は、請求項７記載の車両用バッテリの劣化度判定方法において、前記放電電流が所定期間に所定値以上増大するものであることを検出するに当たって、周期的に測定した前記バッテリの端子電圧と放電電流とを少なくとも最新の所定期間分収集して格納、記憶しておき、該記憶しておいた最新の所定期間分の端子電圧と放電電流とに基づいて、前記放電電流が所定期間に所定値以上の増大があることを検出したとき、該所定期間内の端子電圧と放電電流とにより、前記単位時間当たりの変化量を求めることを特徴とする車両用バッテリの劣化度判定方法に存する。
【００２４】
上述した請求項８記載の手順によれば、周期的に測定したバッテリの端子電圧と放電電流とを少なくとも最新の所定期間分収集して格納、記憶していて、この記憶した最新の所定期間分の端子電圧と放電電流とに基づいて、放電電流が所定期間に所定値以上の増大があることを検出したとき、所定期間内の端子電圧と放電電流とにより、単位時間当たりの変化量を求めるようにしているので、都合のよい任意の時点で純抵抗を求めるための処理を行うことができる。
【００２５】
請求項９記載の発明は、図１（ａ）の基本構成図に示す如く、車両に搭載されている負荷に電力を供給するため車両に搭載されたバッテリの劣化度を判定する車両用バッテリの劣化度判定装置において、前記搭載されたバッテリから前記負荷に所定値を越えて単調増大し最大値から所定値以下に単調減少する放電電流が流れたとき周期的に測定して得た前記バッテリの端子電圧と放電電流とに基づいて、前記搭載されたバッテリの純抵抗を測定する純抵抗測定手段２３ａ−１と、前記搭載されたバッテリに相当するバッテリの未使用時における充電状態に対応するバッテリの純抵抗と寿命時における充電状態に対応するバッテリの純抵抗とをそれぞれ予め記憶している純抵抗記憶手段２３ｂ−１と、前記純抵抗測定手段により測定した純抵抗と、該純抵抗を測定したときの前記搭載されたバッテリの充電状態に対応する前記純抵抗記憶手段に予め記憶されている当該バッテリの未使用時における純抵抗及び寿命時における純抵抗とに基づいて、前記搭載されたバッテリの劣化度を算出し判定する劣化度算出判定手段２３ａ−２とを備えることを特徴とする車両用バッテリの劣化度判定装置に存する。
【００２６】
上述した請求項９記載の発明によれば、純抵抗測定手段２３ａ−１が、車両に搭載されているバッテリから負荷に所定値を越えて単調増大し最大値から所定値以下に単調減少する放電電流が流れたとき周期的に測定して得た車両に搭載されたバッテリの端子電圧と放電電流とに基づいて、搭載されたバッテリの純抵抗を測定する。劣化度算出判定手段２３ａ−２が、測定した純抵抗と、純抵抗を測定したときの搭載されたバッテリの充電状態に対応する純抵抗記憶手段２３ｂ−１に予め記憶されている未使用時における純抵抗及び寿命時における純抵抗とに基づいて、搭載されたバッテリの劣化度を算出し判定しているので、車両使用状態において、バッテリの劣化度を自動的に判定することができる。
【００２７】
請求項１０記載の発明は、請求項９記載の車両用バッテリの劣化度判定装置において、劣化度算出判定手段２３ａ−２は、前記劣化度を、前記測定した純抵抗と前記未使用時の純抵抗との差を、前記寿命時の純抵抗と前記未使用時の純抵抗との差で除した値の百分率によって求めることを特徴とする車両用バッテリの劣化度判定装置に存する。
【００２８】
上述した請求項１０記載の発明によれば、劣化度算出判定手段２３ａ−２が劣化度を百分率によって求めているので、劣化の進行具合を具体的な数値によって客観的に把握できる。
【００２９】
請求項１１記載の発明は、図１（ｂ）の部分構成図に示す如く、請求項９又は１０に記載の車両用バッテリの劣化度判定装置において、前記純抵抗測定手段２３ａ−１は、前記負荷に所定値を越えて単調増大し最大値から所定値以下に単調減少する放電電流が流れたときの前記バッテリの端子電圧と放電電流とを周期的に測定する電圧・電流測定手段２３ａ−１１と、該電圧・電流測定手段によって測定した端子電圧と放電電流との相関を示す前記増大する放電電流に対する電圧−電流特性の第１の近似曲線式と前記減少する放電電流に対する電圧−電流特性の第２の近似曲線式とを求める近似曲線式算出手段２３ａ−１２と、前記第２の近似曲線式によって表される電圧−電流特性曲線上に定めた第２の点に対応する第２の放電電流が流れたとき第２の電圧降下を生じさせる、バッテリの純抵抗と第２の分極抵抗成分からなる第２の合成抵抗と同一の抵抗値を有する第１の想定点を前記第１の近似曲線式によって表される電圧−電流特性曲線上に、前記第１の近似曲線式によって表される電圧−電流特性曲線上に定めた第１の点に対応する第１の放電電流が流れたとき第１の電圧降下を生じさせるバッテリの純抵抗と第１の分極抵抗成分からなる第１の合成抵抗と同一の抵抗値を有する第２の想定点を前記第２の近似曲線式によって表される電圧−電流特性曲線上にそれぞれ想定し、前記第２の点と前記第１の想定点とを結ぶ直線の第１の傾斜を、前記第２の放電電流と前記第２の想定点での放電電流とによってそれぞれ生じる、前記第２の分極抵抗成分による電圧降下の差分を補正した上で、前記第２の分極抵抗成分による電圧降下分を除いた第１の補正傾斜を求めるとともに、前記第１の点と前記第２の想定点とを結ぶ直線の第２の傾斜を、前記第１の放電電流と前記第２の想定点での放電電流とによってそれぞれ生じる、前記第１の分極抵抗成分による電圧降下の差分を補正した上で、前記第１の分極抵抗成分による電圧降下分を除いた第２の補正傾斜を求め、該求めた前記第１の補正傾斜と第２の補正傾斜とを加算平均して平均傾斜を求める演算手段２３ａ−１３とを備え、該該演算手段によって求めた前記平均傾斜を前記バッテリの前記純抵抗として測定することを特徴とする車両用バッテリの劣化度判定装置に存する。
【００３０】
上述した請求項１１記載の発明によれば、バッテリから車両の負荷に電力を供給して負荷に所定値を越えて単調増大し最大値から所定値以下に単調減少する放電電流が流れたときのバッテリの端子電圧と放電電流とを電圧・電流測定手段２３ａ−１１が周期的に測定する。電圧・電流測定手段によって測定した端子電圧と放電電流との相関を示す増大する放電電流に対する電圧−電流特性の第１の近似曲線式と減少する放電電流に対する電圧−電流特性の第２の近似曲線式とを近似曲線式算出手段２３ａ−１２が求める。
【００３１】
バッテリの純抵抗として測定するに当たって、演算手段２３ａ−１３が、まず、第２の近似曲線式によって表される電圧−電流特性曲線上に定めた第２の点に対応する第２の放電電流が流れたとき第２の電圧降下を生じさせる、バッテリの純抵抗と第２の分極抵抗成分からなる第２の合成抵抗と同一の抵抗値を有する第１の想定点を前記第１の近似曲線式によって表される電圧−電流特性曲線上に、前記第１の近似曲線式によって表される電圧−電流特性曲線上に定めた第１の点に対応する第１の放電電流が流れたとき第１の電圧降下を生じさせるバッテリの純抵抗と第１の分極抵抗成分からなる第１の合成抵抗と同一の抵抗値を有する第２の想定点を前記第２の近似曲線式によって表される電圧−電流特性曲線上にそれぞれ想定する。
【００３２】
次に、第２の点と第１の想定点とを結ぶ直線の第１の傾斜を、第２の放電電流と第２の想定点での放電電流とによってそれぞれ生じる、第２の分極抵抗成分による電圧降下の差分を補正した上で、第２の分極抵抗成分による電圧降下分を除いた第１の補正傾斜を求めるとともに、第１の点と第２の想定点とを結ぶ直線の第２の傾斜を、第１の放電電流と第２の想定点での放電電流とによってそれぞれ生じる、第１の分極抵抗成分による電圧降下の差分を補正した上で、第１の分極抵抗成分による電圧降下分を除いた第２の補正傾斜を求める。
【００３３】
そして最後に、この求めた第１の補正傾斜と第２の補正傾斜とを加算平均して平均傾斜を求め、この求めた平均傾斜をバッテリの純抵抗として測定する。したがって、車両の通常の使用状態で負荷に電力を供給したときのバッテリの端子電圧と放電電流とを測定し、この測定の結果得られるデータを処理するだけで、バッテリの純抵抗を測定することができる
【００３４】
請求項１２記載の発明は、請求項１１記載の車両用バッテリの劣化度判定装置において、前記演算手段は、前記第１の点と前記第２の点とを、前記第１の近似曲線式と前記第２の近似曲線式を求めるため測定した前記バッテリの端子電圧と放電電流の存在する範囲内に定めることを特徴とする車両用バッテリの劣化度判定装置に存する。
【００３５】
上述した請求項１２記載の発明によれば、演算手段は、第１の点と第２の点とを、第１の近似曲線式と第２の近似曲線式を求めるため測定したバッテリの端子電圧と放電電流の存在する範囲内に定めているので、傾斜を求めるための少なくとも一方が実データに基づくものとなり、実際から大きく外れた点を使用することをなくすることができる。
【００３６】
請求項１３記載の発明は、請求項１１又は１２記載の車両用バッテリの劣化度判定装置において、前記近似曲線式算出手段は、前記第１の近似曲線式と前記第２の近似曲線式を求めるために、前記電圧・電流測定手段により周期的に測定した前記バッテリの端子電圧と放電電流とを、最新の所定時間分収集して格納、記憶する記憶手段２３ｂ−２を有することを特徴とする車両用バッテリの劣化度判定装置に存する。
【００３７】
上述した請求項１３記載の発明によれば、記憶手段２３ｂ−２が、第１の近似曲線式と第２の近似曲線式を求めるために、電圧・電流測定手段により周期的に測定したバッテリの端子電圧と放電電流とを、最新の所定時間分収集して格納、記憶しているので、この記憶した実データを用いて、第１の近似曲線式と第２の近似曲線式とを求めるに必要な放電電流が流れたことを確認してから、記憶してある実データを用いて第１の近似曲線式と前記第２の近似曲線式とを求めることができる。
【００３８】
請求項１４記載の発明は、図１（ｃ）の部分構成図に示す如く、請求項９又は１０に記載の車両用バッテリの劣化度判定装置において、前記純抵抗測定手段２３ａ−１は、前記負荷に放電電流が流れたときの前記バッテリの端子電圧と放電電流とを周期的に測定して得る電圧・電流測定手段２３ａ−１５と、所定期間に所定値以上に急激に増大する放電電流が流れたときの前記電圧・電流測定手段によって得られた端子電圧と放電電流に基づいて、前記端子電圧と放電電流との単位時間当たりの変化量を求める変化量算出手段２３ａ−１６と、該変化量算出手段によって求めた端子電圧の変化量を放電電流の変化量により除算する除算手段２３ａ−１７とを備え、該除算手段によって求めた値をバッテリの純抵抗として測定することを特徴とする車両用バッテリの劣化度判定装置に存する。
【００３９】
上述した請求項１４記載の発明によれば、電圧・電流測定手段２３ａ−１５が、車両に搭載されている負荷に放電電流が流れたときの車両に搭載されたバッテリの端子電圧と放電電流とを周期的に測定して得る。変化量算出手段２３ａ−１６が、所定期間に所定値以上に急激に増大する放電電流が流れたときの電圧・電流測定手段によって得られた端子電圧と放電電流に基づいて、端子電圧と放電電流との単位時間当たりの変化量を求める。除算手段２３ａ−１７が、変化量算出手段によって求めた端子電圧の変化量を放電電流の変化量により除算する。そして、除算手段によって求めた値をバッテリの純抵抗として測定する。
【００４０】
所定期間に所定値以上に急激に増大する放電電流が流れたときの端子電圧と放電電流に基づいて、変化量算出手段２３ａ−２が、端子電圧と放電電流との単位時間当たりの変化量を求めているので、この単位時間に増大した放電電流によって発生する分極は非常に小さく、端子電圧の変化量、すなわち、電圧降下に分極抵抗成分の占める割合が極めて小さく、実質的に純抵抗によるものとみなすことができ、よって、除算手段２３ａ−１７が、端子電圧の変化量を放電電流の変化量により除して求めた値はバッテリの純抵抗を表すとすることができる。
【００４１】
請求項１５記載の発明は、請求項１４記載の車両用バッテリの劣化度判定装置において、前記変化量算出手段は、前記端子電圧と放電電流との単位時間当たりの変化量を求めるに当たって、前記放電電流が所定期間に所定値以上増大するものであることを検出する電流増加検出手段２３ａ−１６１を有することを特徴とする車両用バッテリの劣化度判定装置に存する。
【００４２】
上述した請求項１５記載の発明によれば、変化量算出手段２３ａ−１６が端子電圧と放電電流との単位時間当たりの変化量を求めるに当たって、電流増加検出手段２３ａ−１６１が放電電流が所定期間に所定値以上増大するものであることを検出していて、放電電流が所定期間に所定値以上増大するものでないときには、単位時間当たりの変化量を求めることがないので、測定した純抵抗の精度を常に所定範囲内のものとすることができる。
【００４３】
請求項１６記載の発明は、請求項１５記載の車両用バッテリの劣化度判定装置において、前記変化量算出手段は、前記放電電流が所定期間に所定値以上の増大があることを検出するに当たって、周期的に測定した前記バッテリの端子電圧と放電電流とを少なくとも最新の所定期間分収集して格納、記憶しておく記憶手段２３ｂ−３を更に有し、前記記憶手段に記憶しておいた最新の所定期間分の端子電圧と放電電流とに基づいて、前記電流増加検出手段が前記放電電流が所定期間に所定値以上の増大があることを検出したとき、前記所定期間内の端子電圧と放電電流とにより、前記単位時間当たりの変化量を求めることを特徴とする車両用バッテリの劣化度判定装置に存する。
【００４４】
上述した請求項１６記載の発明によれば、記憶手段２３ｂ−３が、周期的に測定したバッテリの端子電圧と放電電流とを少なくとも最新の所定期間分収集して格納、記憶していて、この記憶した最新の所定期間分の端子電圧と放電電流とに基づいて、電流増加検出手段２３ａ−１６１が放電電流が所定期間に所定値以上の増大があることを検出したとき、変化量算出手段２３ａ−２が所定期間内の端子電圧と放電電流とにより、単位時間当たりの変化量を求めるようにしているので、都合のよい任意の時点で純抵抗を求めるための処理を行うことができる。
【００４５】
【発明の実施の形態】
以下、本発明による車両用バッテリの劣化度判定方法を、本発明による車両用バッテリの劣化度判定装置の一実施形態と共に、図２を参照して説明する。
【００４６】
図２は本発明の車両用バッテリの劣化度判定方法を適用した本発明の一実施形態に係る車両用バッテリの劣化度判定装置の概略構成を一部ブロックにて示す説明図であり、図中符号１で示す本実施形態の車両用バッテリ純抵抗測定装置は、エンジン３に加えてモータジェネレータ５を有するハイブリッド車両に搭載されている。
【００４７】
そして、このハイブリッド車両は、通常時はエンジン３の出力のみをドライブシャフト７からディファレンシャルケース９を介して車輪１１に伝達して走行させ、高負荷時には、バッテリ１３からの電力によりモータジェネレータ５をモータとして機能させて、エンジン３の出力に加えてモータジェネレータ５の出力をドライブシャフト７から車輪１１に伝達し、アシスト走行を行わせるように構成されている。
【００４８】
また、このハイブリッド車両は、減速時や制動時にモータジェネレータ５をジェネレータ（発電機）として機能させ、運動エネルギを電気エネルギに変換してバッテリ１３を充電させるように構成されている。
【００４９】
なお、モータジェネレータ５はさらに、図示しないスタータスイッチのオンに伴うエンジン３の始動時に、エンジン３のフライホイールを強制的に回転させるセルモータとして用いられるが、その場合にモータジェネレータ５には、短時間に大きな電流が流される。スタータスイッチのオンによりモータジェネレータ５によってエンジン３が始動されると、イグニッションキー（図示せず。）の操作解除に伴って、スタータスイッチがオフになってイグニッションスイッチやアクセサリスイッチのオン状態に移行し、これに伴ってバッテリ１３から流れる放電電流は、定常電流に移行する。
【００５０】
本実施形態の車両用バッテリの劣化度判定装置１は、アシスト走行用のモータやセルモータとして機能するモータジェネレータ５等、電装品に対するバッテリ１３の放電電流Ｉや、ジェネレータとして機能するモータジェネレータ５からのバッテリ１３に対する充電電流を検出する電流センサ１５と、バッテリ１３に並列接続した１Ｍオーム程度の抵抗を有し、バッテリ１３の端子電圧Ｖを検出する電圧センサ１７とを備えている。
【００５１】
また、本実施形態の車両用バッテリの劣化度判定装置１は、上述した電流センサ１５及び電圧センサ１７の出力がインタフェース回路（以下、「Ｉ／Ｆ」と略記する。）２１におけるＡ／Ｄ変換後に取り込まれるマイクロコンピュータ（以下、「マイコン」と略記する。）２３をさらに備えている。
【００５２】
そして、前記マイコン２３は、ＣＰＵ２３ａ、ＲＡＭ２３ｂ、及び、ＲＯＭ２３ｃを有しており、このうち、ＣＰＵ２３ａには、ＲＡＭ２３ｂ及びＲＯＭ２３ｃの他、前記Ｉ／Ｆ２１が接続されており、また、上述した図示しないスタータスイッチ、イグニッションスイッチやアクセサリスイッチ、モータジェネレータ５以外の電装品（負荷）のスイッチ等が、さらに接続されている。
【００５３】
前記ＲＡＭ２３ｂは、各種データ記憶用のデータエリア及び各種処理作業に用いるワークエリアを有しており、前記ＲＯＭ２３ｃには、ＣＰＵ２３ａに各種処理動作を行わせるための制御プログラムが格納されている。
【００５４】
なお、上述した電流センサ１５及び電圧センサ１７の出力である電流値及び電圧値は、短い周期で高速にサンプリングされてＩ／Ｆ２１を介して、マイコン２３のＣＰＵ２３ａに取り込まれ、取り込まれた電流値及び電圧値は前記ＲＡＭ２３ｂのデータエリア（記憶手段に相当する）に所定期間前のものから最新のものまでの分、格納、記憶される。この記憶された実データは、バッテリの純抵抗を測定し、測定した純抵抗によりバッテリの劣化度を判定するために利用される。
【００５５】
次に、前記ＲＯＭ２３ｃに格納された制御プログラムに従いＣＰＵ２３ａが行うバッテリ劣化度判定処理を、図３を参照して説明する。
【００５６】
バッテリ１３からの給電を受けてマイコン２３が起動しプログラムがスタートすると、ＣＰＵ２３ａは、まず初期設定を実行する（ステップＳ１）。
【００５７】
ステップＳ１の初期設定が済んだならば、次に、ＣＰＵ２３ａは、電流センサ１５の検出したバッテリ１３の放電電流Ｉと電圧センサ１７の検出したバッテリ１３の端子電圧ＶとのＡ／Ｄ変換値を対にしてＩ／Ｆ２１を介して読み込み、読み込んだ実データの最新のものを、所定時間分、ＲＡＭ２３ｂのデータエリアに格納、記憶して収集する実データ収集処理を実行する（ステップＳ２）。このステップＳ２における実データ収集処理は常に継続的に行われる。
【００５８】
続いて、ステップＳ２において収集された放電電流Ｉと端子電圧Ｖとの最新の所定時間分の実データに基づいて、バッテリの純抵抗を測定する純抵抗測定処理が行われ（ステップＳ３）、測定された純抵抗は劣化度を算出し判定する（ステップＳ４）ために利用される。測定したバッテリの純抵抗を利用してバッテリの劣化度を算出し判定するため、前記ＲＡＭ２３ｂのバックアップされたデータエリア或いは不揮発性メモリ（図示せず）には、当該バッテリの充電状態に対応するバッテリの純抵抗を未使用時と寿命時についてそれぞれ測定されて予め記憶されている。
【００５９】
なお、未使用時の新品のバッテリの純抵抗Ｒｎと、寿命時の使い古したバッテリの純抵抗Ｒａは、充電状態によって変化し、充電状態に対して図４に示すような相関関係を有し、ＲＡＭ２３ｂのバックアップされたデータエリア或いは不揮発性メモリ（図示せず）に記憶するに当たって、データテーブル化される。車載されたバッテリの充電状態Ｘ％は適宜の方法によって測定されることができるので、この測定した充電状態を利用することで、純抵抗の測定が行われたときのバッテリの充電状態Ｘ％に対応する未使用時の純抵抗Ｒｎと寿命時の純抵抗Ｒａのデータを読み出すことができる。
【００６０】
ステップＳ４における劣化度算出判定処理では、具体的には、ステップＳ３で測定した純抵抗Ｒと、充電状態Ｘ％に対応する予め記憶した劣化のない新品の純抵抗Ｒｎとの差を、寿命が近くなった純抵抗Ｒａと新品の当該バッテリの純抵抗Ｒｎとの差で除して求めた値の百分率を求めることが行われる。すなわち、（Ｒ−Ｒｎ）／（Ｒａ−Ｒｎ）×１００％なる計算が行われる。
【００６１】
バッテリの使用状態、すなわち、負荷に放電電流が流れたとき周期的に測定して得たバッテリの端子電圧と放電電流とに基づいて、純抵抗を測定して得ることによって、簡単な計算によってバッテリの劣化度を百分率による具体的な数値として算出することができ、バッテリを使用しているときに、劣化の進行具合を客観的に把握できるようになる。
【００６２】
なお、上述した例は、劣化度を算出し判定する方法の一例であって、測定した純抵抗と純抵抗を測定したときの充電状態に対応する未使用時の純抵抗及び寿命時の純抵抗とがあれば、これらに基づいて、バッテリの劣化度を算出し判定することができ、車両使用状態において、バッテリの劣化度を自動的に判定することができる。
【００６３】
次に、バッテリの劣化度を判定するために使用するバッテリの純抵抗の測定の仕方の２例を以下説明する。
【００６４】
〔第１の例〕
因みに、１２Ｖ車、４２Ｖ車、ＥＶ車、ＨＥＶ車には、スタータモータ、モータジェネレータ、走行用モータなどの大電流を必要とする負荷を搭載されており、これらの負荷に電力を供給するバッテリの電圧−電流（Ｖ−Ｉ）特性の例は、図５及び図６に示すようになる。
【００６５】
Ｖ−Ｉ特性は図５に示すように、１次式Ｖ＝ａＩ＋ｂで近似する方式も考えられるが、図７に示す分極抵抗成分の非直線形の特性の影響により、１次式では高い相関を有する式を得ることは難しいので、本実施形態では、図６に示すように、Ｖ＝ａＩ² ＋ｂＩ＋ｃなる２次式の近似曲線式を最小二乗法によって得ることによって、高い相関を有する近似曲線式を用いることを必須とする。
【００６６】
上述したような大電流を必要とする負荷を駆動したとき、１回の放電によって、所定値を越えて単調増大し最大値から所定値以下に単調減少する放電電流が流れる。このときのバッテリの端子電圧と放電電流とを周期的に測定してこれら端子電圧と放電電流との相関を示す実データに基づいて、図８のグラフ中に示すように、放電が開始され増加方向に向かう増大する放電電流に対するＶ−Ｉ特性の第１の近似曲線式Ｍ１と、電流が最大に達しその後減少方向に向かう減少する放電電流に対するＶ−Ｉ特性の第２の近似曲線式Ｍ２の２つの式が得られる。なお、図８中に記載の式は実データによって得られた具体的な近似曲線式の一例である。これらの２つの近似曲線式Ｍ１と近似曲線式Ｍ２との違いを以下分析する。
【００６７】
一方の近似曲線式Ｍ１の場合、放電開始時点での分極抵抗成分を基準にすると、放電が開始し電流が増加すると、分極抵抗成分は徐々に増加していく。その後、電流が最大値になったところで、分極抵抗成分がピークに達し、電流の減少に伴って分極が解消していくはずである。しかし、実際には、電流の減少に比例して分極抵抗成分は解消するのではなく反応が遅れて現れるため、近似曲線式Ｍ２の場合、増加方向と同じＶ−Ｉ特性を示さず、増加方向よりも大きな電圧降下を発生させることになり、電流の増加と減少時にそれぞれ対応する２つの近似曲線式Ｍ１及びＭ２が得られることになる。
【００６８】
上述したＶ−Ｉ特性の２つの近似曲線式Ｍ１及びＭ２で表される近似曲線を用いて、バッテリの純抵抗Ｒを測定する方法を、図９乃至図１１を参照して、以下具体的に説明する。
【００６９】
まず、図９に示すように、上記近似曲線式の一方Ｍ１で表される近似曲線上の実データの範囲内に任意の点Ａを選択し、式Ｍ１の近似曲線の縦軸に対する切片Ｃ１から近似曲線上の点Ａまでの電圧降下ΔＶ１を求める。このΔＶ１を点Ａでの電流Ｉ１で除算した値は、純抵抗Ｒに純抵抗を除くその他の抵抗成分である分極抵抗成分のその時点での値Ｒｐｏｌ１を加算した合成抵抗である。すなわち、
Ｒ＋Ｒｐｏｌ１＝ΔＶ１／Ｉ１
である。
【００７０】
同様に、図９に示すように、上記近似曲線式の他方Ｍ２で表される近似曲線上の実データの範囲内に任意の点Ｂを選択し、式Ｍ２の近似曲線の縦軸に対する切片Ｃ２から近似曲線上の点Ｂまでの電圧降下ΔＶ２を求める。このΔＶ２を点Ｂでの電流Ｉ２で除算した値は、純抵抗Ｒに純抵抗を除くその他の抵抗成分である分極抵抗成分のその時点での値Ｒｐｏｌ２を加算した合成抵抗である。すなわち、
Ｒ＋Ｒｐｏｌ２＝ΔＶ２／Ｉ２
である。
【００７１】
上記２点Ａ及びＢの合成抵抗の値の差ΔＲは
ΔＲ＝Ｒ＋Ｒｐｏｌ１−（Ｒ＋Ｒｐｏｌ２）＝Ｒｐｏｌ１−Ｒｐｏｌ２
となり、点Ａ及びＢにおける分極抵抗成分の差となる。これは、１回の放電中の純抵抗Ｒは変化しないことから明らかである。
【００７２】
なお、式Ｍ１で表される近似曲線上には、図１０に示すように、式Ｍ２の近似曲線上に選択した任意の点Ｂにおける合成抵抗（Ｒ＋Ｒｐｏｌ２）に等しい値（Ｒ＋Ｒｐｏｌ１′）をもった点Ａ′が存在する。また、式Ｍ２で表される近似曲線上にも、図９に示すように、式Ｍ１の近似曲線上に選択した任意の点Ａにおける合成抵抗（Ｒ＋Ｒｐｏｌ１）に等しい値（Ｒ＋Ｒｐｏｌ２′）をもった点Ｂ′が存在する。すなわち、
Ｒ＋Ｒｐｏｌ１′＝Ｒ＋Ｒｐｏｌ２となる点Ａ′が式Ｍ１で表される近似曲線上に、Ｒ＋Ｒｐｏｌ１＝Ｒ＋Ｒｐｏｌ２′となる点Ｂ′が式Ｍ２で表される近似曲線上にそれぞれ存在する。
【００７３】
要するに、点Ａ′における電流及び電圧をそれぞれＩ１′及びＶ１′とし、点Ｂ′における電流及び電圧をそれぞれＩ２′及びＶ２′とすると、点Ａ′の座標（Ｉ１′、Ｖ１′）と点Ｂの座標（Ｉ２、Ｖ２）の分極抵抗成分の値が互いに等しく、また点Ａの座標（Ｉ１、Ｖ１）と点Ｂ′（Ｉ２′、Ｖ２′）の分極抵抗成分の値も互いに等しいことがわかる。
【００７４】
まず、Ｂ点を基準とし、この点Ｂの合成抵抗の値（Ｒ＋Ｒｐｏｌ２）と等しい値を持つ点Ａ′の電流Ｉ１′と電圧Ｖ１′の算出の仕方を以下説明する。
【００７５】
今、式Ｍ１で表される近似曲線の縦軸に対する切片Ｃ１からこの点Ａ′までの電圧降下をΔＶ１′とすると、これは
ΔＶ１′＝Ｃ１−（ａ１Ｉ１′²＋ｂ１Ｉ１′＋Ｃ１）＝（Ｒ＋Ｒｐｏｌ２）Ｉ１′
となり、この式を整理すると、
−（ａ１Ｉ１′＋ｂ１）＝Ｒ＋Ｒｐｏｌ２
となり、点Ａ′の電流Ｉ１′は
Ｉ１′＝−（ｂ１＋Ｒ＋Ｒｐｏｌ２）／ａ１
となる。なお、Ｒ＋Ｒｐｏｌ２（＝Ｒ＋Ｒｐｏｌ１′）＝ΔＶ２／Ｉ２（＝ΔＶ１′／Ｉ１′）であるので、

となる。また、点Ａ′の電圧Ｖ１′は、上記式から明らかなように、
Ｖ１′＝ａ１Ｉ１′²＋ｂ１Ｉ１′＋Ｃ１
であるので、点Ａ′の座標（Ｉ１′、Ｖ１′）は既知の値から定められる。
【００７６】
同様にして、Ａ点を基準とし、この点Ａの抵抗値（Ｒ＋Ｒｐｏｌ１）と等しい値を持つ点Ｂ′の電流Ｉ２′と電圧Ｖ２′も、

により既知の値から算出できる。なお、ΔＶ２′は、式２で表される近似曲線の縦軸に対する切片Ｃ２からこの点Ｂ′までの電圧降下である。
【００７７】
上述のようにして、点Ａ′の座標（Ｉ１′、Ｖ１′）が定まったら、図１０に示すように、点Ａ′の座標（Ｉ１′、Ｖ１′）と点Ｂの座標（Ｉ２、Ｖ２）とを結ぶ直線Ｌ１の傾斜を求めることによって合成抵抗の値Ｒ１が求められる。この合成抵抗の値Ｒ１は、純抵抗と分極抵抗成分Ｒｐｏｌ２とからなる合成抵抗によって生じる電圧降下の差（Ｖ１′−Ｖ２）を各点において流れる電流の差（Ｉ１′−Ｉ２）によって除算することによって求められる。すなわち、
Ｒ１＝（Ｖ１′−Ｖ２）／（Ｉ１′−Ｉ２）
となる。
【００７８】
同様にして、点Ｂ′の座標（Ｉ２′、Ｖ２′）が定まったら、、図１１に示すように、点Ｂ′の座標（Ｉ２′、Ｖ２′）と点Ａの座標（Ｉ１、Ｖ１）とを結ぶ直線Ｌ２の傾斜を求めることによって合成抵抗の値Ｒ２が求められる。この合成抵抗の値Ｒ２は、純抵抗と分極抵抗成分Ｒｐｏｌ１とからなる合成抵抗によって生じる電圧降下の差（Ｖ１−Ｖ２′）を各点において流れる電流の差（Ｉ１−Ｉ２′）によって除算することによって求められる。すなわち、
Ｒ２＝（Ｖ１−Ｖ２′）／（Ｉ１−Ｉ２′）
となる。
【００７９】
しかしながら、上述のようにして求められる合成抵抗の値Ｒ１及びＲ２は、純抵抗と分極抵抗成分とからなる合成抵抗によって生じる電圧降下の差を各点において流れる電流の差によって除算して求めたもので、純抵抗とは一致しない。２点間の傾きを純抵抗と一致させるには、分極抵抗成分によって生じる電圧降下分を除いた電圧降下の差を電流差によって除算してやればよい。
【００８０】
先ず、点Ｂを基準にした場合について説明すると、今、合成抵抗の値Ｒ１を
Ｒ１＝Ｒ１′＋Ｒｐｏｌ２＝Ｒ１′＋Ｒｐｏｌ１′
とすると、抵抗Ｒ１′に点Ａ′の電流Ｉ１′と点Ｂの電流Ｉ２との差に相当する電流が流れることによって生じる電圧降下は、分極抵抗成分Ｒｐｏｌ１′（又はＲｐｏｌ２）に点Ａ′の電流Ｉ１′と点Ｂの電流Ｉ２の差に相当する電流が流れることによって生じる電圧降下分だけ、点Ａ′の電圧を持ち上げて補正してやればよく、次式が成立する。
Ｒ１′（Ｉ１′−Ｉ２）＝〔Ｖ１′＋Ｒｐｏｌ１′（Ｉ１′−Ｉ２）〕−Ｖ２
【００８１】
この式を整理すると、
Ｒ１′（Ｉ１′−Ｉ２）＝（Ｖ１′−Ｖ２）＋Ｒｐｏｌ１′（Ｉ１′−Ｉ２）となる。ここで、Ｒｐｏｌ１′＝ΔＶ１′／Ｉ１′−Ｒ１′であるので、
Ｒ１′（Ｉ１′−Ｉ２）＝（Ｖ１′−Ｖ２）＋（ΔＶ１′／Ｉ１′−Ｒ１′）（Ｉ１′−Ｉ２）
２Ｒ１′（Ｉ１′−Ｉ２）＝（Ｖ１′−Ｖ２）＋ΔＶ１′／Ｉ１′（Ｉ１′−Ｉ２）
となり、結果として、
Ｒ１′＝〔（Ｖ１′−Ｖ２）＋（ΔＶ１′／Ｉ１′）（Ｉ１′−Ｉ２）〕／２（Ｉ１′−Ｉ２）
が求められる。なお、（ΔＶ１′／Ｉ１′）は（ΔＶ２／Ｉ２）と置き換えることができる。
【００８２】
次に、点Ａを基準にした場合にも同様にして
Ｒ２＝Ｒ２′＋Ｒｐｏｌ１＝Ｒ２′＋Ｒｐｏｌ２′
とすると、この抵抗Ｒ２′に点Ａの電流Ｉ１と点Ｂ′の電流Ｉ２′の差に相当する電流が流れることによって生じる電圧降下は、分極抵抗成分Ｒｐｏｌ１２′（又はＲｐｏｌ１）に点Ａの電流Ｉ１と点Ｂ′の電流Ｉ２′との差に相当する電流が流れることによって生じる電圧降下分、点Ｂ′の電圧を引き下げて補正してやればよく、次式が成立する。
Ｒ２′（Ｉ１−Ｉ２′）＝Ｖ１−〔Ｖ２′−Ｒｐｏｌ２′（Ｉ１−Ｉ２′）〕
【００８３】
この式を整理すると、
Ｒ２′（Ｉ１−Ｉ２′）＝（Ｖ１−Ｖ２′）＋Ｒｐｏｌ２′（Ｉ１−Ｉ２′）となる。ここで、Ｒｐｏｌ２′＝ΔＶ２′／Ｉ２′−Ｒ２′であるので、
Ｒ２′（Ｉ１−Ｉ２′）＝（Ｖ１−Ｖ２′）＋（ΔＶ２′／Ｉ２′−Ｒ２′）（Ｉ１−Ｉ２′）
２Ｒ２′（Ｉ１−Ｉ２′）＝（Ｖ１−Ｖ２′）＋ΔＶ２′／Ｉ２′（Ｉ１−Ｉ２′）
となり、結果として、
Ｒ２′＝〔（Ｖ１−Ｖ２′）＋（ΔＶ２′／Ｉ２′）（Ｉ１−Ｉ２′）〕／２（Ｉ１−Ｉ２′）
が求められる。なお、（ΔＶ２′／Ｉ２′）は（ΔＶ１／Ｉ１）と置き換えることができる。
【００８４】
上述したように求められた２つの値Ｒ１′及びＲ２′は、２つの点Ａ及びＢを基準にし、異なる分極抵抗成分（Ｒｐｏｌ１′＝Ｒｐｏｌ２）と（Ｒｐｏｌ１＝Ｒｐｏｌ２′）を用い、しかも異なる切片Ｃ１からの電圧降下Δ１′（ΔＶ１）と切片Ｃ２からの電圧降下Δ２′（ΔＶ２）を用いて求めたものであるので、真の純抵抗Ｒとなり得ない。したがって、両者の加算平均
Ｒ＝（Ｒ１′＋Ｒ２′）／２
をとることによって、真の純抵抗Ｒが求められる。
【００８５】
そこで、純抵抗の測定方法を図９乃至図１１を参照して先ず説明する。車両の負荷に電力を供給するため車両に搭載された、例えばスタータモータ、モータジェネレータ、走行用モータなどの大電流を必要とする負荷が動作されると、バッテリからは所定値を越えて単調増大し最大値から所定値以下に単調減少する放電電流が流れる。このときのバッテリの端子電圧と放電電流とを、例えば１ｍｓの周期にてサンプリングすることで、バッテリの端子電圧と放電電流との組が多数得られる。
【００８６】
このようにして得られたバッテリの端子電圧と放電電流との組の最新のものを、所定時間分、例えばＲＡＭなどの書換可能な記憶手段としてのメモリに格納、記憶して収集する。メモリに格納、記憶して収集した端子電圧と放電電流との組を用いて、最小二乗法により、端子電圧と放電電流との相関を示す増大する放電電流に対する電圧−電流特性の例えばＶ１（Ｉ）＝ａ１Ｉ²＋ｂ１＋Ｃ１なる２次式で表される第１の近似曲線式Ｍ１と、減少する放電電流に対する電圧−電流特性の例えばＶ２（Ｉ）＝ａ２Ｉ²＋ｂ２Ｉ＋Ｃ２なる２次式で表される第２の近似曲線式Ｍ２とを求める。
【００８７】
次に、第１の近似曲線式Ｍ１によって表される電圧−電流特性曲線上に第１の点Ａを、第２の近似曲線式Ｍ２によって表される電圧−電流特性曲線上に第２の点Ｂをそれぞれ定める。このとき、第１の近似曲線式Ｍ１によって表される電圧−電流特性曲線上に定められる第１の点Ａと、第２の近似曲線式Ｍ２によって表される電圧−電流特性曲線上に定められる第２の点Ｂとは、各近似曲線式を求める際に使用された端子電圧と放電電流の実データの存在する範囲内に好ましく定められる。このように定めることによって、その後、各点に対応する想定点を想定する際に、想定点が大きく外れた位置に想定されることがなくなる。また、好ましくは、第１の点Ａと第２の点Ｂは、分極抵抗成分が最大となる点の両側に定められるのがよい。このように定めることによって、最大点の両側に想定点が定められるようになるようになり、その後、純抵抗を求める際の精度が高まるようになる。
【００８８】
そして、第２の点Ｂに対応する第２の放電電流Ｉ２が流れたとき第２の電圧降下ΔＶ２を生じさせる、バッテリの純抵抗と第２の分極抵抗成分Ｒｐｏｌ２からなる第２の合成抵抗Ｒ２と同一の抵抗値を有する第１の想定点Ａ′を第１の近似曲線式Ｍ１上に、第１の点Ａに対応する第１の放電電流Ｉ１が流れたとき第１の電圧降下ΔＶ１を生じさせる、バッテリの純抵抗と第１の分極抵抗成分Ｒｐｏｌ１からなる第１の合成抵抗Ｒ１と同一の抵抗値を有する第２の想定点Ｂ′を第２の近似曲線式Ｍ２上にそれぞれ想定する。
【００８９】
２つの想定点Ａ′及びＢ′が想定できたら、第２の点Ｂと第１の想定点Ａ′とを結ぶ直線Ｌ１の第１の傾斜Ｒ１を、第２の放電電流Ｉ２と第１の想定点Ａ′での放電電流Ｉ１′とによってそれぞれ生じる、第２の分極抵抗成分Ｒｐｏｌ２による電圧降下の差分Ｒｐｏｌ２（Ｉ１′−Ｉ２）を補正した上で、第２の分極抵抗成分Ｒｐｏｌ２による電圧降下分を除いた第１の補正傾斜Ｒ１′を求めるとともに、前記第１の点と前記第２の想定点Ｂ′とを結ぶ直線Ｌ２の第２の傾斜Ｒ２を、第１の放電電流Ｉ１と第２の想定点Ｂ′での放電電流Ｉ２′とによってそれぞれ生じる、第１の分極抵抗成分Ｒｐｏｌ１による電圧降下の差分Ｒｐｏｌ１（Ｉ１−Ｉ２′）を補正した上で、第１の分極抵抗成分Ｒｐｏｌ１による電圧降下分を除いた第２の補正傾斜Ｒ２′を求める。
【００９０】
このうようにして求めた第１の補正傾斜Ｒ１′と第２の補正傾斜Ｒ２′とを加算平均して平均傾斜を求め、この求めた平均傾斜をバッテリの純抵抗Ｒとして測定する。
【００９１】
次に、前記ＲＯＭ２３ｃに格納された制御プログラムに従いＣＰＵ２３ａが行う図３のフローチャート中のステップＳ３の純抵抗測定処理の具体的な内容を、図１２を参照して説明する。
【００９２】
図３のフローチャート中のステップＳ２において収集された放電電流Ｉと端子電圧Ｖとの最新の所定時間分の実データは分析され、最小二乗法を適用して、電圧−電流特性の２次の近似曲線式を求めるのに適当なものであるかどうかが判定される。すなわち、バッテリから所定値を越えて単調増大し最大値から所定値以下に単調減少する放電電流が流れているかどうかを分析する分析処理を行う（ステップＳ２１）。
【００９３】
ステップＳ２１における分析の結果、電圧−電流特性の２次の近似曲線式を求めるのに適当なものが収集されているとき（ステップＳ２２のＹ）、増大する放電電流に対する電圧−電流特性のＶ１（Ｉ）＝ａ１Ｉ²＋ｂ１＋Ｃ１なる２次式で表される第１の近似曲線式Ｍ１と、減少する放電電流に対する電圧−電流特性の例えばＶ２（Ｉ）＝ａ２Ｉ²＋ｂ２Ｉ＋Ｃ２なる２次式で表される第２の近似曲線式Ｍ２とを求める近似曲線式算出処理を実行する（ステップＳ２３）。
【００９４】
ステップＳ２３の近似曲線式算出処理によって、２つの近似曲線式Ｍ１及びＭ２が求まった後、次に、バッテリの純抵抗を求めるための演算処理を実行する（ステップＳ２４）。ステップＳ２４における演算処理では、近似曲線式Ｍ２によって表される電圧−電流特性曲線上に定めた点に対応する放電電流が流れたとき電圧降下を生じさせる、バッテリの純抵抗と第２の分極抵抗成分からなる合成抵抗と同一の抵抗値を有する第１の想定点を第１の近似曲線式Ｍ１によって表される電圧−電流特性曲線上に想定する。また、第１の近似曲線式Ｍ１によって表される電圧−電流特性曲線上に定めた点に対応する放電電流が流れたとき電圧降下を生じさせるバッテリの純抵抗と第１の分極抵抗成分からな合成抵抗と同一の抵抗値を有する第２の想定点を第２の近似曲線式Ｍ２によって表される電圧−電流特性曲線上に想定する。
【００９５】
ステップＳ２４における演算処理では、また、近似曲線式Ｍ２によって表される電圧−電流特性曲線上に定めた点と第１の想定点とを結ぶ直線の第１の傾斜を、第２の近似曲線式によって表される電圧−電流特性曲線上に定めた点に対応する放電電流と第２の想定点での放電電流とによってそれぞれ生じる、２の分極抵抗成分による電圧降下の差分を補正した上で、第２の分極抵抗成分による電圧降下分を除いた第１の補正傾斜を求める。
【００９６】
ステップＳ２４における演算処理では、さらに、近似曲線式Ｍ１によって表される電圧−電流特性曲線上に定めた点と第２の想定点とを結ぶ直線の第２の傾斜を、第１の近似曲線式によって表される電圧−電流特性曲線上に定めた点に対応する放電電流と第２の想定点での放電電流とによってそれぞれ生じる、１の分極抵抗成分による電圧降下の差分を補正した上で、第１の分極抵抗成分による電圧降下分を除いた第２の補正傾斜を求める。そして、ステップＳ２４において求めた第１の補正傾斜と第２の補正傾斜とを加算平均して平均傾斜を求め、平均傾斜をバッテリの純抵抗として測定し、この測定した純抵抗は種々の目的で使用するため、ＲＡＭ２３ｂのデータエリアに格納されて記憶される（ステップＳ２５）。ステップＳ２５の測定処理が終了したら、次にステップＳ２２の判定がＹとなって、ステップＳ２３の近似曲線式算出処理、ステップＳ２４の演算処理を実行する機会がくるまで、図３のフローチャート中のステップＳ２の収集処理とステップＳ２１の分析処理とを繰り返し実行する。
【００９７】
また、本実施形態の車両用バッテリ純抵抗測定装置１では図３のフローチャートにおけるステップＳ２が請求項中の電圧・電流測定手段に対する処理となっており、図１２のフローチャートにおけるステップＳ２３が請求項中の近似曲線算出手段に対応する処理となっており、ステップＳ２４が請求項中の演算手段に対応する処理となっている。
【００９８】
次に、本実施形態の純抵抗測定動作（作用）について説明する。
【００９９】
まず、ハイブリッド車両のモータジェネレータ５以外の電装品（負荷）が作動したり、モータジェネレータ５がモータとして機能するように作動していて、それに伴いバッテリ１３が放電を行っている状態では、負荷に所定値を越えて単調増大し最大値から所定値以下に単調減少する放電電流が流れたときのバッテリの端子電圧と放電電流とが周期的に測定される。
【０１００】
また、周期的に測定された最新のものが、所定時間分、ＲＡＭ２３ｂのデータエリアに格納、記憶して収集され、収集された放電電流Ｉと端子電圧Ｖとの最新の所定時間分の実データは分析され、最小二乗法を適用して、電圧−電流特性の２次の近似曲線式を求めるのに適当なものであるかどうかが判定される。すなわち、バッテリから所定値を越えて単調増大し最大値から所定値以下に単調減少する放電電流が流れているかどうかが分析される。
【０１０１】
このため、電圧−電流特性の２次の近似曲線式を求めるのに適当なものが収集されるまで、近似曲線式算出処理が行われることがなく、近似曲線式算出処理も、過去に収集した所定時間分の実データを用いて行わればよいので、端子電圧と放電電流との周期的な測定に同期して処理を行わなくてもよく、早い処理速度が求められない。
【０１０２】
さらに、第１の近似曲線式と第２の近似曲線式を求めるため測定したバッテリの端子電圧と放電電流の存在する範囲内に定めた２つの点を用いているが、必要とされる精度との関係において支障がない限り、これに制限されるものでない。しかし、精度を保つためには、第１の近似曲線式の単調増加あるいは第２の近似曲線式の単調減少の範囲内に定めることが好ましい。
【０１０３】
なお、上述した実施の形態では、Ｖ−Ｉ特性の２つの近似曲線式Ｍ１及びＭ２で表される近似曲線上の実データの存在する範囲内に任意の点Ａ及びＢを選択しているが、これらの点を２つの近似曲線式Ｍ１及びＭ２上の、これらの式を求めるため測定したバッテリの放電電流の最大値に相当する点Ｐに選択し、両方の点を共通のデータを使用して特定することで、誤差の入ることを少なくすることができる。
【０１０４】
〔第２の例〕
因みに、１２Ｖ車、４２Ｖ車、ＥＶ車、ＨＥＶ車には、スタータモータ、モータジェネレータ、走行用モータなどの大電流を必要とする負荷を搭載されており、これらの負荷は、スイッチのオンによってバッテリから電力を供給すると、図１３に示すように、その電流の流れはじめにラッシュ電流と称される急激に増大する大電流が流れた後、急速に定常電流に減少する電流特性を有する。
【０１０５】
上述したような大電流を必要とする負荷を駆動したとき、１回の放電によって、所定値を越えて単調増大し最大値から所定値以下に単調減少する放電電流が流れる。このときのバッテリの端子電圧と放電電流とを周期的に測定してこれら端子電圧と放電電流との相関を示す実データに基づいてグラフに示すと、図１４に示すように、放電が開始され増加方向に向かう所定期間に所定値以上に急激に増大する放電電流に対する電流増大Ｖ−Ｉ特性と、電流が最大に達しその後減少方向に向かう減少する放電電流に対する電流減少Ｖ−Ｉ特性の２つが得られる。これらの２つの特性の違いを以下分析する。
【０１０６】
一方の例えば数ミリ秒の所定期間内に例えば２００Ａ乃至２５０Ａの所定値以上に急激に増大する放電電流に対する電流増大Ｖ−Ｉ特性の場合、放電開始時点での分極抵抗成分を基準にすると、放電が開始し電流が増加しても、電流の増加速度が分極抵抗成分の発生速度に比べて非常に早いため、放電電流がピークに達しても、電流の大きさに対応した分極抵抗成分は発生せず、電流が流れることによって発生する端子電圧の電圧降下中に占める分極抵抗成分による電圧降下の割合が極めて少なく、その大部分は純抵抗成分によるものである。
【０１０７】
このことは、他方の電流減少Ｖ−Ｉ特性を分析することによってより明らかになる。すなわち、電流が最大値に達した後、電流の減少に伴って分極抵抗成分が解消していくはずであるが、実際には、電流の減少に比例して分極抵抗成分は解消するのではなく、むしろ増大していく。これは分極抵抗成分がその発生速度が遅いため、電流が減少してもなお増大しているためであり、電流減少Ｖ−Ｉ特性上のある電流に対応する分極抵抗成分が発生したとき、電圧降下中に占める分極抵抗成分による電圧降下分が最大の割合になる。最終的には定常電流に応じた分極抵抗成分となったところから電流の減少に伴って遅れて解消するようになり、分極抵抗成分が完全に解消するまで、電流が０になっても分極抵抗成分によるバッテリの端子電圧の電圧降下は残る。
【０１０８】
上述したように、所定期間に所定値以上に急激に増大する放電電流が流れたときのバッテリの端子電圧は、バッテリによる純抵抗に放電電流が流れることによって生じる電圧降下を反映した電圧がほとんどを占め、分極抵抗成分による電圧はほとんど現れないことに着目して、上述した２つのＶ−Ｉ特性のうちの電流増大Ｖ−Ｉ特性を用いて、バッテリの純抵抗Ｒを測定する方法を、図１５乃至図１７を参照して、以下具体的に説明する。
【０１０９】
車両に搭載されたスタータモータ、モータジェネレータ、走行用モータなどの大電流を必要とする負荷に放電電流が流れたときのバッテリの端子電圧と放電電流とを、例えば１ミリ秒の比較的早い周期でサンプリングすることによって周期的に測定して得、この測定により得た端子電圧と放電電流に基づいて、端子電圧Ｖと放電電流Ｉとの単位時間ΔＴ当たりの変化量ΔＶ、ΔＩを求める。つづいて、この求めた端子電圧Ｖの変化量ΔＶを放電電流Ｉの変化量ΔＩにより除して求めた値を純抵抗Ｒとして測定する。
【０１１０】
なお、端子電圧と放電電流との単位時間当たりの変化量を求めるに当たって、放電電流が所定期間に所定値以上の増大するものであることを検出することにより、端子電圧Ｖの変化量ΔＶを放電電流Ｉの変化量ΔＩにより除して求めた値により測定した純抵抗Ｒの精度を所定範囲内に入ることを保証する。すなわち、所定期間に所定値以上の増大する放電電流の場合には、分極の発生が極めて少なくその抵抗成分による電圧降下が純抵抗によるものに比べて無視することができるくらいに極めて小さいことによって、精度が所定範囲内に入るようになる。また、事前に、放電電流が所定期間に所定値以上の増大するものであることを検出することにより、この条件に当てはまらない場合に、端子電圧と放電電流との単位時間当たりの変化量を求めることを行わなくて済み、無駄な処理をなくすることができる。
【０１１１】
また、放電電流が所定期間に所定値以上の増大があることを検出するに当たって、周期的に測定したバッテリの端子電圧と放電電流とを少なくとも最新の所定期間分収集して格納、記憶しておく。そして、この記憶しておいた最新の所定期間分の端子電圧と放電電流とに基づいて、放電電流が所定期間に所定値以上の増大があることを検出したとき、記憶しておいた最新の所定期間分の端子電圧と放電電流とに基づいて、この所定期間内の端子電圧と放電電流とにより、端子電圧と放電電流との単位時間当たりの変化量を求めることにより、都合のよい任意の時点で処理を行うことができる。
【０１１２】
具体的には、例えばスタータモータ、モータジェネレータ、走行用モータなどの大電流を必要とする負荷が動作されると、バッテリからは所定値を越えて単調増大し最大値から所定値以下に単調減少する放電電流が流れる。このときのバッテリの端子電圧と放電電流とを、例えば１ｍｓの周期にてサンプリングすることで、周期的に測定することによって、バッテリの端子電圧と放電電流との組が多数得られる。
【０１１３】
このようにして得られたバッテリの端子電圧と放電電流との組の最新のものを、所定期間分、例えばＲＡＭなどの書換可能な記憶手段としてのメモリに格納、記憶して収集する。メモリに格納、記憶して収集した端子電圧と放電電流との組を用いて、放電電流が所定期間に所定値以上増大するものであることを検出し、放電電流が所定期間に所定値以上増大するものであることが検出されたとき、端子電圧と放電電流との単位時間当たりの変化量を、メモリに格納、記憶して収集した端子電圧と放電電流との組を用いて求める。そして、この求めた端子電圧の変化量を放電電流の変化量により除算することによって求めた値をバッテリの純抵抗として測定する。
【０１１４】
次に、前記ＲＯＭ２３ｃに格納された制御プログラムに従いＣＰＵ２３ａが行う図３のフローチャート中のステップＳ３の純抵抗測定処理の具体的な内容を、図１７のフローチャートを参照して説明する。
【０１１５】
図３のフローチャート中のステップＳ２において収集された放電電流Ｉと端子電圧Ｖとの最新の所定時間分の実データについて、バッテリから所定値を越えて単調増大する放電電流が流れているかどうかを分析する分析処理を行う（ステップＳ３１）。
【０１１６】
ステップＳ３１における分析の結果、電圧−電流特性を求めるのに適当なものが収集され、放電電流が所定期間に所定値以上増大したものであるか否かを判定する（ステップＳ３３２）。放電電流が所定期間に所定値以上増大したものであるとき（ステップＳ３２のＹ）、すなわち、放電電流が所定期間に所定値以上増大するものであることをことを検出したときには、上記所定期間内に収集された放電電流Ｉと端子電圧Ｖとの単位時間当たりの変化量ΔＩ、ΔＶを求める（ステップＳ３３）。
【０１１７】
ステップＳ３３において放電電流Ｉと端子電圧Ｖとの単位時間当たりの変化量ΔＩ、ΔＶが求まったら、次に端子電圧の変化量ΔＶを放電電流の変化量ΔＩにより除して求めた値をバッテリの純抵抗Ｒとして測定し（ステップＳ３４）、この測定した純抵抗は種々の目的で使用するため、ＲＡＭ２３ｂのデータエリアに格納されて記憶される（ステップＳ３５）。なお、ステップＳ３２の判定がＮのときには、図３のステップＳ２に戻って放電電流Ｉと端子電圧Ｖとの最新の所定時間分の実データが収集され、ステップＳ３１の分析の結果、ステップＳ３２の判定がＹとなるまで、上述したステップＳ２乃至Ｓ３２が繰り返される。
【０１１８】
また、図３のフローチャートにおけるステップＳ２が請求項中の電圧・電流測定手段２３ａ−１５に対する処理となっており、ステップＳ３２が請求項中の電流増加検出手段２３ａ−１６１に対応する処理となっており、ステップＳ３３が請求項中の変化量算出手段２３ａ−１６に対応する処理となっており、ステップＳ３４が請求項中の除算手段２３ａ−１７なっている。
【０１１９】
次に、純抵抗測定動作（作用）について説明する。
【０１２０】
まず、ハイブリッド車両のモータジェネレータ５以外の電装品（負荷）が作動したり、モータジェネレータ５がモータとして機能するように作動した場合、それに伴いバッテリ１３が放電を開始した状態では、負荷に所定期間に所定値以上に単調増大し最大値から単調減少し、定常状態に至る放電電流が流れ、少なくともこのときのバッテリの端子電圧と放電電流とが周期的に測定される。勿論、常時バッテリの端子電圧と放電電流とが周期的に測定されてもよい。
【０１２１】
また、周期的に測定された最新のものが、所定期間分、ＲＡＭ２３ｂのデータエリアに格納、記憶して収集され、収集された放電電流Ｉと端子電圧Ｖとの最新の所定期間分の実データにういて、バッテリから所定期間に所定値以上増大した放電電流が流れたかどうかが分析される。
【０１２２】
このため、適当なものが収集されるまで、純抵抗測定処理が行われることがなく、純抵抗測定処理も、過去に収集した所定期間分の実データを用いて行わればよいので、端子電圧と放電電流との周期的な測定に同期して処理を行わなくてもよく、早い処理速度が求められない。
【０１２３】
さらに、所定期間に所定値以上増大した放電電流の存在は、必要とされる精度との関係において支障がない限り、所定期間と所定値は任意に定めることが好ましい。
【０１２４】
また、上述の例では、負荷としてモータジェネレータ５以外の電装品（負荷）が作動した場合も挙げているが、定常状態において一定の放電電流が流れている状態において、任意の負荷の動作によってその動作開始時にラッシュ電流のように、所定期間内に所定値を超えるような放電電流が流れたとき、この放電電流の増大に伴って生じる端子電圧の電圧降下は純抵抗によって生じたものとみなせることに着目し、この短時間に生じた端子電圧の変化量を放電電流の変化量によって除すことで純抵抗を測定している。
【０１２５】
なお、上述の実施の形態では、負荷に流れる放電電流の内の単調増大している放電電流の区間を純抵抗を測定するために用いているが、所定期間内に所定値以上の電流変化が生じるのであれば、単調減少している放電電流を純抵抗を測定するために用いるようにしてもよい。
【０１２６】
また、上述の実施の形態では、負荷に流れる放電電流を利用してバッテリの純抵抗を測定するようにしているが、バッテリを充電する充電電流が、所定期間内に所定値以上変化する場合には、この充電電流を純抵抗測定のために利用することもできる。
【０１２７】
すなわち、車両に搭載されている負荷に電力を供給するため車両に搭載されたバッテリの純抵抗を測定するに当たって、バッテリに充電電流が流れ込んだときのバッテリの端子電圧と充電電流とを周期的に測定して得、所定期間に所定値以上に急激に増大する充電電流が流れたときの、測定によって得られた端子電圧と充電電流に基づいて、端子電圧と充電電流との単位時間当たりの変化量を求め、この求めた端子電圧の変化量を充電電流の変化量により除して求めた値をバッテリの純抵抗として測定することもできる。
【０１２８】
なお、本願明細書中において使用している「純抵抗」なる用語は、真のオーミック抵抗を意味するものでなく、オーミック抵抗以外の抵抗成分は含むが殆ど無視できる程度にしか含まれておらず、真のオーミック抵抗に非常に近似したものであることを意味する。
【０１２９】
【発明の効果】
以上説明したように、請求項１又は９記載の発明によれば、測定したバッテリの純抵抗と、純抵抗を測定したときの充電状態に対応する予め定めた未使用時における純抵抗及び予め定めた寿命時における純抵抗とに基づいて、搭載されたバッテリの劣化度を算出し判定し、車両使用状態において、搭載されたバッテリの劣化度を自動的に判定することができるので、車両使用中のバッテリの劣化度を判定することのできる車両用バッテリの劣化度判定方法及び装置を提供することができる。
【０１３０】
上述した請求項２又は１０記載の発明によれば、劣化度を、百分率によって求め、劣化の進行具合を具体的な数値によって客観的に把握できるようにしているので、人の感覚に頼って判断することの必要をなくし、判断誤りが少なく信頼性の高い車両用バッテリの劣化度判定方法及び装置を提供することができる。
【０１３１】
上述した請求項３又は１１記載の発明によれば、車両の通常の使用状態で負荷に電力を供給したときのバッテリの端子電圧と放電電流との測定の結果得られるデータを処理して２つの近似曲線を得、この２つの近似曲線上の分極抵抗成分の等しくなる２点を結ぶ直線の傾斜を利用して求めたバッテリの純抵抗によりバッテリの劣化度を判定しているので、車両使用中のバッテリの劣化度を判定することのできる車両用バッテリの劣化度判定方法及び装置を提供することができる。
【０１３２】
上述した請求項４又は１２記載の発明によれば、２つの近似曲線を利用してバッテリの純抵抗を求めるに当たって、近似曲線式を求めるため測定したバッテリの端子電圧と放電電流の存在する範囲内に２点のうちの１点を選定し、実際から大きく外れた点を使用することをなくすることで、純抵抗の測定精度を安定したもに保つことのでき、これを利用して行うバッテリの劣化度の判定が精度よく行える車両用バッテリの劣化度判定方法及び装置を提供することができる。
【０１３３】
上述した請求項５又は１３記載の発明によれば、記憶した実データを用いて、近似曲線式を求めるに必要な放電電流が流れたことを確認してから、記憶してある実データを用いて近似曲線式を求め、無駄な処理を省くとともに、リアルタイムな高速処理を行うことなくしているので、これを利用して行うバッテリの劣化度の判定を安価に行える車両用バッテリの劣化度判定方法及び装置を提供することができる。
【０１３４】
上述した請求項６又は１４記載の発明によれば、単位時間に増大した放電電流によって発生する分極は非常に小さく、端子電圧の変化量、すなわち、電圧降下に分極抵抗成分の占める割合が極めて小さく、実質的に純抵抗によるものとみなし、端子電圧の変化量を放電電流の変化量により除して求めた値をバッテリの純抵抗として測定し、車両使用中でも測定できるバッテリの純抵抗を利用して劣化度の判定を行っているので、車両使用中でもバッテリの劣化度を判定することのできる車両用バッテリの劣化度判定方法及び装置を提供することができる。
【０１３５】
上述した請求項７又は１５記載の発明によれば、測定した純抵抗の精度を常に所定範囲内のものとすることができるので、これを利用した劣化度の判定も安定したもに保つことのできる車両用バッテリの劣化度判定方法及び装置を提供することができる。
【０１３６】
上述した請求項８又は１６記載の発明によれば、都合のよい任意の時点で純抵抗を求めるための処理を行うことができ、無駄な処理を省くとともに、リアルタイムな高速処理を行うことなく測定できる純抵抗を利用しているので、劣化度の判定を融通性をもって行える車両用バッテリの劣化度判定方法及び装置を提供することができる。
【図面の簡単な説明】
【図１】本発明の車両用バッテリの劣化度判定装置の基本構成を示すブロック図である。
【図２】本発明の車両用バッテリの劣化度判定方法を適用した本発明の一実施形態に係る車両用バッテリの劣化度判定装置の概略構成を一部ブロックにて示す説明図である。
【図３】図２中のマイコンがバッテリの劣化度判定のため予め定めたプログラムに従って行う処理を示すフローチャートである。
【図４】バッテリの充電状態に対する純抵抗の変化を未使用時と寿命時について示すグラフである。
【図５】１次近似式で表したＶ−Ｉ特性の一例を示すグラフである。
【図６】２次近似曲線式で表したＶ−Ｉ特性の一例を示すグラフである。
【図７】電流に対する分極による電圧変化の一例を示すグラフである。
【図８】１回の放電によって得られる２つの２次の近似曲線式で表される近似特性曲線の一例を示すグラフである。
【図９】２つの近似特性曲線上への２つの任意の点の定め方を説明するためのグラフである。
【図１０】一方の近似特性曲線に定めた点に対する想定点の定め方と２点間の傾斜の補正の仕方とを説明するためのグラフである。
【図１１】他方の近似特性曲線に定めた点に対する想定点の定め方と２点間の傾斜の補正の仕方とを説明するためのグラフである。
【図１２】図２中のマイコンが純抵抗測定のため予め定めたプログラムに従って行う処理を示すフローチャートである。
【図１３】大電流負荷の電流特性を示すグラフである。
【図１４】図１２に示す電流特性のときのＶ−Ｉ特性を示すグラフである。
【図１５】本発明を説明するための電流特性を示すグラフである。
【図１６】本発明を説明するための電流増加Ｖ−Ｉ特性を示すグラフである。
【図１７】図２中のマイコンが純抵抗測定のため予め定めたプログラムに従って行う処理を示すフローチャートである。
【符号の説明】
２３ａ−１純抵抗測定測定手段（ＣＰＵ）
２３ａ−２劣化度算出判定手段（ＣＰＵ）
２３ａ−１１電圧・電流測定手段（ＣＰＵ）
２３ａ−１２近似曲線式算出手段（ＣＰＵ）
２３ａ−１３演算手段（ＣＰＵ）
２３ａ−１５電圧・電流測定手段（ＣＰＵ）
２３ａ−１６変化量算出手段（ＣＰＵ）
２３ａ−１６１電流増加検出手段（ＣＰＵ）
２３ａ−１７除算手段（ＣＰＵ）
２３ｂ−１純抵抗記憶手段（ＲＡＭ）
２３ｂ−２記憶手段（ＲＡＭ）
２３ｂ−３記憶手段（ＲＡＭ）[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle battery deterioration degree determination method and apparatus for determining the deterioration degree of a battery mounted on a vehicle in order to supply electric power to a load mounted on the vehicle.
[0002]
[Prior art]
Conventionally, in order to determine the degree of deterioration of a battery during use of a vehicle, the startability of the engine has deteriorated in the case of a lead battery for a vehicle, and the travel distance has shortened in the case of an electric vehicle battery. In general, judgment was made by relying on human senses.
[0003]
[Problems to be solved by the invention]
However, it is not reliable to make a judgment by relying on human senses, and often the judgment is wrong and the battery runs out.
[0004]
Therefore, in view of the above-described situation, an object of the present invention is to provide a vehicle battery deterioration degree determination method and apparatus that can determine the deterioration degree of a battery in use.
[0005]
[Means for Solving the Problems]
The present invention according to claim 1 to claim 9 that achieves the above object is a method for determining the degree of deterioration of a vehicle battery, and the present invention according to claims 10 to 18 is an apparatus for determining a degree of deterioration of a vehicle battery. Each of the inventions has been made by paying attention to the fact that the pure resistance of the battery changes in accordance with the degree of deterioration of the battery.
[0006]
  In order to solve the above-mentioned problem, the invention according to claim 1 is a vehicle battery deterioration degree determination method for determining a deterioration degree of a battery mounted on a vehicle in order to supply electric power to a load mounted on the vehicle. ,Corresponds to the battery installedBatteryWhen not in useBattery pure resistance corresponding to the state of chargeAnd the pure resistance of the battery corresponding to the state of charge at the end of its life.Respectively,From the installed batteryTo the loadMonotonically increases beyond the specified value and decreases monotonously from the maximum value to the specified valueBased on the terminal voltage and discharge current of the battery obtained by periodically measuring when the discharge current flows,MountedThe pure resistance of the battery is measured, the measured pure resistance, and the measured pure resistanceOf the mounted batteryThe predetermined unused time corresponding to the state of chargeInPure resistance and the predetermined lifeInBased on net resistance andMountedThe present invention resides in a method for determining the degree of deterioration of a vehicle battery, wherein the degree of deterioration of the battery is calculated and determined.
[0007]
  According to the procedure of claim 1 described above,The pure resistance of the battery corresponding to the state of charge when the battery corresponding to the mounted battery is not in use and the pure resistance of the battery corresponding to the state of charge at the end of the lifetime are respectively determined in advance,Mounted on the vehicleFrom batteryTo loadMonotonically increases beyond the specified value and decreases monotonously from the maximum value to the specified valueThe pure resistance of the battery is measured based on the terminal voltage and the discharge current of the battery mounted on the vehicle obtained by periodically measuring when the discharge current flows. Next, the measured pure resistance and the measured pure resistanceOf the installed batteryWhen not in use corresponding to the state of chargeInPure resistance and predetermined lifetimeInBased on net resistance andMountedSince the battery deterioration level is calculated and judged,MountedThe degree of deterioration of the battery can be automatically determined.
[0008]
According to a second aspect of the present invention, in the method for determining a degree of deterioration of a vehicle battery according to the first aspect, the degree of deterioration is calculated by calculating a difference between the measured pure resistance and the pure resistance when not in use. The present invention resides in a method for determining a deterioration level of a vehicle battery, characterized in that it is obtained by a percentage of a value divided by a difference between a pure resistance and the pure resistance when not in use.
[0009]
According to the above-described procedure according to claim 2, the degree of deterioration is obtained as a percentage, so that the progress of deterioration can be objectively grasped by specific numerical values.
[0010]
According to a third aspect of the present invention, in the method for determining a deterioration level of a vehicle battery according to the first or second aspect, a discharge current that monotonously increases beyond a predetermined value and monotonously decreases from a maximum value to a predetermined value or less in the load. A first approximate curve formula of the voltage-current characteristic with respect to the increasing discharge current indicating the correlation between the terminal voltage and the discharge current by periodically measuring the terminal voltage and the discharge current of the battery when flowing, and A second approximate curve equation of the voltage-current characteristic with respect to the decreasing discharge current is obtained, and the first point is placed on the voltage-current characteristic curve represented by the first approximate curve equation, and the second approximate curve. A second resistance is defined on the voltage-current characteristic curve expressed by the equation, and a pure resistance of the battery that causes a second voltage drop when a second discharge current corresponding to the second point flows. And the second polarization resistance component A first assumed current having the same resistance value as that of the second combined resistor is placed on a voltage-current characteristic curve represented by the first approximate curve equation, and a first discharge current corresponding to the first point A second assumed point having the same resistance value as the first combined resistance composed of the pure resistance of the battery and the first polarization resistance component, which causes a first voltage drop when the current flows. A first slope of a straight line connecting the second point and the first assumed point is assumed on the voltage-current characteristic curve represented by the equation, and the second discharge current and the first After correcting the difference in voltage drop due to the second polarization resistance component, which is caused by the discharge current at the assumed point, the first correction slope is obtained by removing the voltage drop due to the second polarization resistance component. And a straight line connecting the first point and the second assumed point. After correcting the difference in voltage drop due to the first polarization resistance component, which is caused by the first discharge current and the discharge current at the second assumed point, respectively, the second slope is corrected. A second correction slope excluding the voltage drop due to the resistance component is obtained, and the obtained first and second slopes are added and averaged to obtain an average slope, and the obtained average slope is used as the pure resistance of the battery. The present invention resides in a method for determining the degree of deterioration of a vehicle battery.
[0011]
According to the above-described procedure according to claim 3, the method has a feature in a method for measuring a pure resistance of a battery used for determining a degree of deterioration of a vehicle battery, and electric power is supplied from the battery to a vehicle load. The terminal voltage and discharge current of a battery are periodically measured when a discharge current that monotonously increases beyond a predetermined value and monotonously decreases from a maximum value to a predetermined value or less flows to the load of the battery. A first approximate curve equation of the voltage-current characteristic with respect to the increasing discharge current and a second approximate curve equation of the voltage-current characteristic with respect to the decreasing discharge current are obtained.
[0012]
Next, a first point is defined on the voltage-current characteristic curve represented by the first approximate curve equation, and a second point is defined on the voltage-current characteristic curve represented by the second approximate curve equation. . The same resistance value as that of the second combined resistance composed of the pure resistance of the battery and the second polarization resistance component that causes the second voltage drop when the second discharge current corresponding to the second point flows. A first voltage drop occurs when a first discharge current corresponding to the first point flows on the voltage-current characteristic curve represented by the first approximate curve equation. The second assumed point having the same resistance value as the first combined resistance composed of the pure resistance of the battery and the first polarization resistance component is represented on the voltage-current characteristic curve expressed by the second approximate curve equation. Assuming that
[0013]
Thereafter, a first slope of a straight line connecting the second point and the first assumed point is caused by the second polarization resistance component generated by the second discharge current and the discharge current at the first assumed point, respectively. After correcting the difference in voltage drop, the first correction slope excluding the voltage drop due to the second polarization resistance component is obtained, and the second of the straight line connecting the first point and the second assumed point is obtained. After correcting the difference in voltage drop due to the first polarization resistance component, which is caused by the first discharge current and the discharge current at the second assumed point, respectively, the voltage drop due to the first polarization resistance formation is corrected. A second correction inclination excluding minutes is obtained.
[0014]
The average slope is obtained by averaging the first and second slopes thus obtained, and the obtained average slope is measured as the pure resistance of the battery. Therefore, measuring the battery terminal voltage and discharge current when power is supplied to the load in the normal use state of the vehicle, and processing the data obtained as a result of this measurement, the pure resistance of the battery is measured Can do.
[0015]
According to a fourth aspect of the present invention, in the vehicle battery deterioration degree determination method according to the third aspect, the first point and the second point are expressed by the first approximate curve formula and the second approximation. The present invention resides in a method for determining the degree of deterioration of a vehicle battery, wherein the battery terminal voltage and discharge current measured in order to obtain a curve equation are determined within a range.
[0016]
According to the above-described procedure according to claim 5, the first point and the second point are obtained by measuring the terminal voltage and the discharge current of the battery measured to obtain the first approximate curve equation and the second approximate curve equation. Since it is set within the existing range, at least one for obtaining the inclination is based on the actual data, and it is possible to eliminate the use of a point greatly deviating from the actual.
[0017]
According to a fifth aspect of the invention, in the vehicle battery deterioration degree determination method according to the third or fourth aspect of the invention, the first approximate curve equation and the second approximate curve equation are periodically measured to obtain the first approximate curve equation and the second approximate curve equation. The terminal voltage and the discharge current of the battery are collected for the latest predetermined time, stored and stored, and the vehicle battery deterioration degree determination method is characterized.
[0018]
According to the above-described procedure according to claim 5, when the first approximate curve equation and the second approximate curve equation are obtained, the terminal voltage and discharge current of the battery measured periodically are collected for the latest predetermined time. Therefore, after confirming that the discharge current necessary for obtaining the first approximate curve equation and the second approximate curve equation has flowed using the stored actual data, The first approximate curve equation and the second approximate curve equation can be obtained using the stored actual data.
[0019]
According to a sixth aspect of the present invention, in the vehicle battery deterioration degree determination method according to the first or second aspect, the terminal voltage and the discharge current of the battery are periodically measured when the discharge current flows through the load. Based on the terminal voltage and the discharge current obtained by the measurement when a discharge current that rapidly increases to a predetermined value or more flows in a predetermined period, the change per unit time of the terminal voltage and the discharge current The present invention resides in a method for determining a deterioration level of a vehicle battery, characterized in that a value obtained by dividing the obtained change amount of the terminal voltage by the change amount of the discharge current is measured as a pure resistance of the battery.
[0020]
According to the above-described procedure of the sixth aspect, the terminal voltage and the discharge current per unit time are calculated based on the terminal voltage and the discharge current when a discharge current that rapidly increases to a predetermined value or more flows in a predetermined period. Since the amount of change is obtained, the polarization generated by the discharge current increased in this unit time is very small, and the amount of change in the terminal voltage, that is, the proportion of the polarization resistance component in the voltage drop is extremely small, which is substantially pure. The value obtained by dividing the change amount of the terminal voltage by the change amount of the discharge current can be regarded as representing the pure resistance of the battery.
[0021]
According to a seventh aspect of the present invention, in the vehicle battery deterioration degree determination method according to the sixth aspect, the discharge current is determined to be a predetermined value during a predetermined period when the change amount per unit time between the terminal voltage and the discharge current is obtained. The present invention resides in a method for determining the degree of deterioration of a vehicle battery, characterized in that it is detected that the amount of increase has increased.
[0022]
According to the above-described procedure according to claim 7, when obtaining the amount of change per unit time between the terminal voltage and the discharge current, it is detected that the discharge current increases by a predetermined value or more in a predetermined period, When the discharge current does not increase by a predetermined value or more in a predetermined period, the amount of change per unit time is not obtained, so that the accuracy of the measured pure resistance can always be within a predetermined range.
[0023]
According to an eighth aspect of the present invention, in the vehicle battery deterioration degree determination method according to the seventh aspect, the periodic measurement is performed when detecting that the discharge current increases by a predetermined value or more in a predetermined period. The terminal voltage and discharge current of the battery are collected and stored and stored for at least the latest predetermined period, and the discharge current is based on the stored terminal voltage and discharge current for the latest predetermined period stored. Deterioration degree of a vehicle battery characterized in that, when it is detected that there is an increase of a predetermined value or more in a predetermined period, a change amount per unit time is obtained from a terminal voltage and a discharge current in the predetermined period It exists in the judgment method.
[0024]
According to the above-described procedure according to claim 8, the terminal voltage and discharge current of the battery measured periodically are collected, stored and stored for at least the latest predetermined period, and the stored latest predetermined period is stored. When it is detected that the discharge current is increased by a predetermined value or more in a predetermined period based on the terminal voltage and the discharge current, the amount of change per unit time is obtained from the terminal voltage and the discharge current in the predetermined period. As a result, processing for obtaining the pure resistance can be performed at any convenient time.
[0025]
  According to the ninth aspect of the present invention, as shown in the basic configuration diagram of FIG. 1 (a), a vehicle battery for judging the degree of deterioration of a battery mounted on a vehicle to supply power to a load mounted on the vehicle. In the degradation degree determination device,From the installed batteryTo the loadMonotonically increases beyond the specified value and decreases monotonously from the maximum value to the specified valueBased on the terminal voltage and discharge current of the battery obtained by periodically measuring when the discharge current flows,MountedPure resistance measuring means 23a-1 for measuring the pure resistance of the battery;Corresponds to the battery installedBatteryWhen not in useThe battery's net resistance corresponding to the state of chargeThe battery's net resistance corresponding to the state of charge at the end of its lifePure resistance storage means 23b-1 stored in advance, pure resistance measured by the pure resistance measurement means, and when the pure resistance is measuredOf the mounted batteryWhen the battery stored in advance in the pure resistance storage means corresponding to the state of charge is not usedInPure resistance and lifeInBased on net resistance andMountedThe vehicle battery deterioration degree determination device includes a deterioration degree calculation determination unit 23a-2 that calculates and determines a battery deterioration degree.
[0026]
  According to the invention described in claim 9, the pure resistance measuring means 23a-1 is mounted on the vehicle.From batteryTo loadMonotonically increases beyond the specified value and decreases monotonously from the maximum value to the specified valueBased on the terminal voltage and discharge current of the battery mounted on the vehicle obtained by periodically measuring when the discharge current flows,MountedMeasure the pure resistance of the battery. The degradation degree calculation determination means 23a-2Corresponds to the state of charge of the installed battery when measuring the pure resistanceWhen not in use stored in advance in the pure resistance storage means 23b-1InPure resistance and lifeInBased on net resistance andMountedSince the battery deterioration degree is calculated and determined, the battery deterioration degree can be automatically determined in the vehicle use state.
[0027]
According to a tenth aspect of the present invention, in the vehicle battery deterioration degree determination device according to the ninth aspect, the deterioration degree calculation determining means 23a-2 determines the deterioration degree by comparing the measured pure resistance and the unused pure resistance. The vehicle battery deterioration degree determination apparatus is characterized in that a difference from a resistance is obtained by a percentage of a value obtained by dividing a difference between a pure resistance at the time of life and a pure resistance when not in use.
[0028]
According to the tenth aspect of the invention described above, since the deterioration degree calculation determination means 23a-2 obtains the deterioration degree as a percentage, the progress of deterioration can be objectively grasped by a specific numerical value.
[0029]
The invention according to claim 11 is the vehicle battery deterioration degree judging device according to claim 9 or 10, wherein the pure resistance measuring means 23a-1 includes the pure resistance measuring means 23a-1, as shown in the partial configuration diagram of FIG. Voltage / current measuring means 23a-11 for periodically measuring the terminal voltage and the discharge current of the battery when a discharge current that monotonously increases beyond a predetermined value and monotonously decreases from a maximum value to a predetermined value or less flows in the load. And a first approximate curve expression of the voltage-current characteristic with respect to the increasing discharge current showing a correlation between the terminal voltage measured by the voltage / current measuring means and the discharge current, and the voltage-current characteristic with respect to the decreasing discharge current. Approximate curve equation calculating means 23a-12 for obtaining a second approximate curve equation, and a second discharge corresponding to the second point defined on the voltage-current characteristic curve represented by the second approximate curve equation Current flows A first assumption point having the same resistance value as the second combined resistance composed of the pure resistance of the battery and the second polarization resistance component, which sometimes causes a second voltage drop, is expressed by the first approximate curve equation. The first voltage when the first discharge current corresponding to the first point defined on the voltage-current characteristic curve represented by the first approximate curve equation flows on the voltage-current characteristic curve A second assumed point having the same resistance value as the first combined resistance composed of the pure resistance of the battery and the first polarization resistance component causing the drop is represented by the second approximate curve equation. A first slope of a straight line connecting the second point and the first assumed point is assumed on the curve, respectively, depending on the second discharge current and the discharge current at the second assumed point. The difference in voltage drop caused by the second polarization resistance component is After correcting, a first correction inclination excluding a voltage drop due to the second polarization resistance component is obtained, and a second inclination of a straight line connecting the first point and the second assumed point is obtained. The voltage due to the first polarization resistance component after correcting the difference in voltage drop due to the first polarization resistance component respectively caused by the first discharge current and the discharge current at the second assumed point. Calculating means 23a-13 for obtaining a second corrected inclination excluding the amount of descent and calculating the average inclination by averaging the obtained first corrected inclination and the second corrected inclination; The average inclination obtained by the means is measured as the pure resistance of the battery.
[0030]
According to the eleventh aspect of the invention described above, when electric power is supplied from the battery to the load of the vehicle, a discharge current that monotonously increases beyond the predetermined value and monotonously decreases from the maximum value to the predetermined value flows to the load. The voltage / current measuring means 23a-11 periodically measures the terminal voltage and discharge current of the battery. A first approximate curve formula of voltage-current characteristics for increasing discharge current and a second approximate curve of voltage-current characteristics for decreasing discharge current showing a correlation between the terminal voltage measured by the voltage / current measuring means and the discharge current The approximate curve equation calculating means 23a-12 obtains the equation.
[0031]
In measuring as the pure resistance of the battery, the calculating means 23a-13 first calculates the second discharge current corresponding to the second point defined on the voltage-current characteristic curve represented by the second approximate curve equation. The first approximate curve equation having a first assumed point having the same resistance value as the second combined resistance composed of the pure resistance of the battery and the second polarization resistance component, which causes a second voltage drop when flowing. When a first discharge current corresponding to a first point defined on the voltage-current characteristic curve represented by the first approximate curve equation flows on the voltage-current characteristic curve represented by A voltage that is expressed by the second approximated curve equation as a second assumed point having the same resistance value as the first combined resistance composed of the pure resistance of the battery and the first polarization resistance component that causes a voltage drop of − Each is assumed on the current characteristic curve.
[0032]
Next, a second polarization resistance component is generated in which a first slope of a straight line connecting the second point and the first assumption point is generated by the second discharge current and the discharge current at the second assumption point, respectively. After correcting the difference in voltage drop due to the second, the first correction slope excluding the voltage drop due to the second polarization resistance component is obtained, and the second of the straight line connecting the first point and the second assumed point is obtained. After correcting the difference in voltage drop due to the first polarization resistance component, which is caused by the first discharge current and the discharge current at the second assumed point, respectively, the voltage drop due to the first polarization resistance component is corrected. A second correction inclination excluding minutes is obtained.
[0033]
Finally, the average inclination is obtained by averaging the obtained first correction inclination and the second correction inclination, and the obtained average inclination is measured as the pure resistance of the battery. Therefore, measuring the battery terminal voltage and discharge current when power is supplied to the load in the normal use state of the vehicle, and processing the data obtained as a result of this measurement, the pure resistance of the battery is measured Can
[0034]
According to a twelfth aspect of the present invention, in the vehicle battery deterioration degree determination device according to the eleventh aspect, the calculation means calculates the first point and the second point as the first approximate curve equation. The present invention resides in a deterioration determination device for a vehicle battery, characterized in that it is determined within a range in which the terminal voltage and discharge current of the battery measured in order to obtain the second approximate curve equation.
[0035]
According to the twelfth aspect of the present invention, the computing means measures the first point and the second point by measuring the terminal voltage of the battery measured to obtain the first approximate curve equation and the second approximate curve equation. Therefore, at least one for obtaining the inclination is based on the actual data, and it is possible to eliminate the use of a point greatly deviating from the actual.
[0036]
According to a thirteenth aspect of the present invention, in the vehicle battery deterioration degree determination apparatus according to the eleventh or twelfth aspect, the approximate curve equation calculating means obtains the first approximate curve equation and the second approximate curve equation. Therefore, the battery terminal voltage and the discharge current measured periodically by the voltage / current measuring unit are collected for the latest predetermined time, stored, and stored. It exists in the deterioration determination apparatus of a vehicle battery.
[0037]
According to the invention described in claim 13 described above, the storage means 23b-2 has the battery measured periodically by the voltage / current measuring means in order to obtain the first approximate curve expression and the second approximate curve expression. Since the terminal voltage and the discharge current are collected and stored for the latest predetermined time, the first approximate curve equation and the second approximate curve equation are obtained using the stored actual data. After confirming that the necessary discharge current has flowed, the first approximate curve equation and the second approximate curve equation can be obtained using the stored actual data.
[0038]
As shown in the partial configuration diagram of FIG. 1 (c), the invention according to claim 14 is the vehicle battery deterioration degree judging device according to claim 9 or 10, wherein the pure resistance measuring means 23a-1 Voltage / current measurement means 23a-15 obtained by periodically measuring the terminal voltage and discharge current of the battery when the discharge current flows through the load, and a discharge current that rapidly increases to a predetermined value or more during a predetermined period. Based on the terminal voltage and discharge current obtained by the voltage / current measurement means when flowing, a change amount calculating means 23a-16 for obtaining a change amount per unit time between the terminal voltage and the discharge current, and the change Division means 23a-17 for dividing the change amount of the terminal voltage obtained by the quantity calculation means by the change amount of the discharge current, and measuring the value obtained by the division means as a pure resistance of the battery. That lies in the deterioration degree determination apparatus of a vehicle battery.
[0039]
According to the invention as set forth in claim 14, the voltage / current measuring means 23a-15 has the terminal voltage and the discharge current of the battery mounted on the vehicle when the discharge current flows through the load mounted on the vehicle. Is measured periodically. Based on the terminal voltage and the discharge current obtained by the voltage / current measuring means when the change amount calculation means 23a-16 flows a discharge current that rapidly increases to a predetermined value or more during a predetermined period, the terminal voltage and the discharge current are calculated. The amount of change per unit time is obtained. The dividing unit 23a-17 divides the change amount of the terminal voltage obtained by the change amount calculating unit by the change amount of the discharge current. Then, the value obtained by the dividing means is measured as the pure resistance of the battery.
[0040]
Based on the terminal voltage and the discharge current when a discharge current that suddenly increases above a predetermined value flows in a predetermined period, the change amount calculating means 23a-2 calculates the change amount per unit time of the terminal voltage and the discharge current. Therefore, the polarization generated by the discharge current increased in this unit time is very small, the amount of change in the terminal voltage, that is, the proportion of the polarization resistance component in the voltage drop is very small, substantially due to the pure resistance Therefore, the value obtained by dividing the change amount of the terminal voltage by the change amount of the discharge current by the dividing means 23a-17 can be regarded as the pure resistance of the battery.
[0041]
According to a fifteenth aspect of the present invention, in the vehicle battery deterioration degree determination device according to the fourteenth aspect, the change amount calculating means calculates the discharge amount per unit time between the terminal voltage and the discharge current. The present invention resides in a vehicle battery deterioration degree judging device having current increase detecting means 23a-161 for detecting that a current increases by a predetermined value or more in a predetermined period.
[0042]
According to the fifteenth aspect of the invention described above, when the change amount calculating means 23a-16 obtains the amount of change per unit time between the terminal voltage and the discharge current, the current increase detecting means 23a-161 has the discharge current for a predetermined period. Therefore, when the discharge current is not increased over a predetermined value during a predetermined period, the amount of change per unit time is not obtained. Can always be within a predetermined range.
[0043]
According to a sixteenth aspect of the present invention, in the vehicle battery deterioration degree determination device according to the fifteenth aspect, the change amount calculating means detects that the discharge current has an increase of a predetermined value or more during a predetermined period. It further has storage means 23b-3 that collects, stores, and stores at least the latest predetermined period of the terminal voltage and discharge current of the battery, which are periodically measured, and the latest stored in the storage means When the current increase detecting means detects that the discharge current is increased by a predetermined value or more in the predetermined period based on the terminal voltage and the discharge current for a predetermined period of time, the terminal voltage and the discharge in the predetermined period The present invention resides in a deterioration degree determination apparatus for a vehicle battery, characterized in that the amount of change per unit time is obtained from an electric current.
[0044]
According to the invention described in claim 16, the storage means 23b-3 collects, stores and stores at least the latest predetermined period of the battery terminal voltage and discharge current measured periodically. Based on the stored terminal voltage and discharge current for the latest predetermined period, when the current increase detection means 23a-161 detects that the discharge current increases by a predetermined value or more in the predetermined period, the change amount calculation means 23a -2 determines the amount of change per unit time based on the terminal voltage and discharge current within a predetermined period, so that a process for obtaining a pure resistance can be performed at any convenient time.
[0045]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a vehicle battery deterioration degree determination method according to the present invention will be described with reference to FIG. 2 together with an embodiment of a vehicle battery deterioration degree determination apparatus according to the present invention.
[0046]
FIG. 2 is an explanatory diagram partially showing a schematic configuration of a vehicle battery deterioration degree determination apparatus according to an embodiment of the present invention to which the vehicle battery deterioration degree determination method of the present invention is applied. The vehicle battery pure resistance measuring apparatus of the present embodiment indicated by reference numeral 1 is mounted on a hybrid vehicle having a motor generator 5 in addition to the engine 3.
[0047]
In this hybrid vehicle, normally, only the output of the engine 3 is transmitted from the drive shaft 7 to the wheels 11 through the differential case 9 and travels. When the load is high, the motor generator 5 is driven by the electric power from the battery 13. In addition to the output of the engine 3, the output of the motor generator 5 is transmitted from the drive shaft 7 to the wheels 11 to perform assist traveling.
[0048]
In addition, this hybrid vehicle is configured to cause the motor generator 5 to function as a generator (generator) during deceleration or braking and to convert the kinetic energy into electric energy to charge the battery 13.
[0049]
The motor generator 5 is further used as a cell motor that forcibly rotates the flywheel of the engine 3 when the engine 3 is started when a starter switch (not shown) is turned on. A large current is passed through. When the engine 3 is started by the motor generator 5 by turning on the starter switch, the starter switch is turned off and the ignition switch and the accessory switch are turned on with the release of the operation of an ignition key (not shown). Accordingly, the discharge current flowing from the battery 13 shifts to a steady current.
[0050]
The vehicle battery deterioration degree determination apparatus 1 of the present embodiment includes a discharge current I of a battery 13 for an electrical component such as a motor for assist driving and a motor generator 5 that functions as a cell motor, and a motor generator 5 that functions as a generator. A current sensor 15 for detecting a charging current for the battery 13 and a voltage sensor 17 having a resistance of about 1 M ohm connected in parallel to the battery 13 and detecting a terminal voltage V of the battery 13 are provided.
[0051]
Further, in the vehicle battery deterioration degree determination apparatus 1 according to the present embodiment, the outputs of the current sensor 15 and the voltage sensor 17 described above are A / D converted in an interface circuit (hereinafter abbreviated as “I / F”) 21. A microcomputer (hereinafter abbreviated as “microcomputer”) 23 to be taken in later is further provided.
[0052]
The microcomputer 23 includes a CPU 23a, a RAM 23b, and a ROM 23c. Of these, the CPU 23a is connected to the I / F 21 in addition to the RAM 23b and the ROM 23c. A switch, an ignition switch, an accessory switch, a switch of an electrical component (load) other than the motor generator 5 are further connected.
[0053]
The RAM 23b has a data area for storing various data and a work area used for various processing operations, and the ROM 23c stores a control program for causing the CPU 23a to perform various processing operations.
[0054]
Note that the current values and voltage values that are the outputs of the current sensor 15 and the voltage sensor 17 described above are sampled at high speed in a short cycle, and are taken into the CPU 23a of the microcomputer 23 via the I / F 21. The voltage value is stored and stored in the data area of the RAM 23b (corresponding to the storage means) from the previous one to the latest one. The stored actual data is used for measuring the pure resistance of the battery and determining the degree of deterioration of the battery based on the measured pure resistance.
[0055]
Next, a battery deterioration degree determination process performed by the CPU 23a according to the control program stored in the ROM 23c will be described with reference to FIG.
[0056]
When the microcomputer 23 is activated to receive power from the battery 13 and the program is started, the CPU 23a first performs initial setting (step S1).
[0057]
When the initial setting in step S1 is completed, the CPU 23a then calculates an A / D conversion value between the discharge current I of the battery 13 detected by the current sensor 15 and the terminal voltage V of the battery 13 detected by the voltage sensor 17. A real data collection process is executed in which the latest actual data read is stored in the data area of the RAM 23b for a predetermined time, and is stored and collected via the I / F 21 (step S2). The actual data collection process in step S2 is always performed continuously.
[0058]
Subsequently, pure resistance measurement processing for measuring the pure resistance of the battery is performed based on the latest actual data of the discharge current I and the terminal voltage V collected in step S2 for a predetermined time (step S3). The obtained pure resistance is used for calculating and determining the degree of deterioration (step S4). In order to calculate and determine the degree of deterioration of the battery using the measured pure resistance of the battery, the backed-up data area or non-volatile memory (not shown) of the RAM 23b has a battery corresponding to the state of charge of the battery. The pure resistance is measured and stored in advance for each of the unused period and the lifetime.
[0059]
The pure resistance Rn of a new battery when not in use and the pure resistance Ra of a used battery at the time of life change depending on the state of charge, and have a correlation as shown in FIG. When the data is stored in the backed-up data area or the non-volatile memory (not shown) of the RAM 23b, the data table is formed. Since the charge state X% of the battery mounted on the vehicle can be measured by an appropriate method, the charge state X% of the battery when the pure resistance is measured can be obtained by using the measured charge state. The corresponding unused pure resistance Rn and lifetime pure resistance Ra data can be read out.
[0060]
Specifically, in the deterioration degree calculation determination process in step S4, the difference between the pure resistance R measured in step S3 and the new pure resistance Rn stored in advance corresponding to the charged state X% without deterioration is calculated as the lifetime. A percentage of the value obtained by dividing by the difference between the near pure resistance Ra and the pure resistance Rn of the new battery is obtained. That is, a calculation of (R−Rn) / (Ra−Rn) × 100% is performed.
[0061]
By measuring and obtaining the pure resistance based on the battery usage status, i.e., the battery terminal voltage and discharge current obtained by periodically measuring when the discharge current flows through the load, the battery can be calculated by simple calculation. The degree of deterioration of the battery can be calculated as a specific numerical value, and the progress of the deterioration can be objectively grasped when the battery is used.
[0062]
The above-described example is an example of a method for calculating and determining the degree of deterioration, and the measured pure resistance and the pure resistance at the time of use corresponding to the state of charge when measuring the pure resistance are measured. Therefore, based on these, the degree of deterioration of the battery can be calculated and determined, and the degree of deterioration of the battery can be automatically determined in the vehicle usage state.
[0063]
Next, two examples of how to measure the pure resistance of the battery used for determining the degree of deterioration of the battery will be described below.
[0064]
[First example]
Incidentally, 12V, 42V, EV, and HEV vehicles are equipped with loads that require a large current, such as starter motors, motor generators, and traveling motors, and batteries that supply electric power to these loads are installed. Examples of voltage-current (V-I) characteristics are as shown in FIGS.
[0065]
As shown in FIG. 5, the V-I characteristic can be approximated by the linear expression V = aI + b. However, due to the influence of the nonlinear characteristic of the polarization resistance component shown in FIG. In this embodiment, as shown in FIG. 6, V = aI is difficult to obtain.² It is essential to use an approximate curve equation having a high correlation by obtaining a quadratic approximate curve equation of + bI + c by the least square method.
[0066]
When a load that requires a large current as described above is driven, a single discharge causes a discharge current that monotonously increases beyond a predetermined value and monotonously decreases from a maximum value to a predetermined value or less. At this time, the battery terminal voltage and the discharge current are periodically measured, and based on the actual data indicating the correlation between the terminal voltage and the discharge current, the discharge starts and increases as shown in the graph of FIG. The first approximate curve formula M1 of the VI characteristic for the increasing discharge current in the direction and the second approximate curve formula M2 of the VI characteristic for the decreasing discharge current in the decreasing direction after the current reaches the maximum. Two equations are obtained. In addition, the formula described in FIG. 8 is an example of a specific approximate curve formula obtained from actual data. The difference between these two approximate curve formulas M1 and M2 will be analyzed below.
[0067]
In the case of one approximate curve equation M1, the polarization resistance component gradually increases as the discharge starts and the current increases with reference to the polarization resistance component at the start of discharge. Thereafter, when the current reaches the maximum value, the polarization resistance component reaches a peak, and the polarization should be eliminated as the current decreases. However, in reality, the polarization resistance component does not disappear in proportion to the decrease in the current, but the response appears with a delay, so the approximate curve equation M2 does not show the same VI characteristic as the increasing direction, and the increasing direction. Therefore, two approximate curve equations M1 and M2 corresponding to the increase and decrease of the current, respectively, are obtained.
[0068]
A method for measuring the pure resistance R of the battery using the approximate curves represented by the two approximate curve equations M1 and M2 of the VI characteristic described above will be specifically described below with reference to FIGS. explain.
[0069]
First, as shown in FIG. 9, an arbitrary point A is selected within the range of actual data on the approximate curve represented by one of the approximate curve formulas M1, and from the intercept C1 with respect to the vertical axis of the approximate curve of the formula M1. A voltage drop ΔV1 to point A on the approximate curve is obtained. The value obtained by dividing ΔV1 by the current I1 at the point A is a combined resistance obtained by adding the value Rpol1 at that time of the polarization resistance component, which is the other resistance component excluding the pure resistance, to the pure resistance R. That is,
R + Rpol1 = ΔV1 / I1
It is.
[0070]
Similarly, as shown in FIG. 9, an arbitrary point B is selected within the range of the actual data on the approximate curve represented by the other M2 of the approximate curve formula, and the intercept C2 with respect to the vertical axis of the approximate curve of Formula M2 To a voltage drop ΔV2 from the approximate curve to point B on the approximate curve. The value obtained by dividing ΔV2 by the current I2 at the point B is a combined resistance obtained by adding the value Rpol2 at that time of the polarization resistance component, which is the other resistance component excluding the pure resistance, to the pure resistance R. That is,
R + Rpol2 = ΔV2 / I2
It is.
[0071]
The difference ΔR between the combined resistance values of the two points A and B is
ΔR = R + Rpol1- (R + Rpol2) = Rpol1-Rpol2
Thus, the difference between the polarization resistance components at points A and B is obtained. This is clear from the fact that the pure resistance R during one discharge does not change.
[0072]
As shown in FIG. 10, the approximate curve represented by Formula M1 has a value (R + Rpol1 ′) equal to the combined resistance (R + Rpol2) at an arbitrary point B selected on the approximate curve of Formula M2. Point A ′ is present. Further, the approximate curve represented by the equation M2 also has a value (R + Rpol2 ′) equal to the combined resistance (R + Rpol1) at an arbitrary point A selected on the approximate curve of the equation M1, as shown in FIG. Point B 'exists. That is,
A point A ′ where R + Rpol1 ′ = R + Rpol2 is present on the approximate curve represented by the equation M1, and a point B ′ where R + Rpol1 = R + Rpol2 ′ is present on the approximate curve represented by the equation M2.
[0073]
In short, if the current and voltage at point A ′ are I1 ′ and V1 ′, and the current and voltage at point B ′ are I2 ′ and V2 ′, respectively, the coordinates (I1 ′, V1 ′) of point A ′ and point B The values of the polarization resistance components at the coordinates (I2, V2) are equal to each other, and the values of the polarization resistance components at the coordinates (I1, V1) of the point A and the points B ′ (I2 ′, V2 ′) are also equal to each other. .
[0074]
First, how to calculate the current I1 ′ and the voltage V1 ′ at the point A ′ having a value equal to the value (R + Rpol2) of the combined resistance at the point B with reference to the point B will be described below.
[0075]
Assuming that the voltage drop from the intercept C1 to the point A ′ with respect to the vertical axis of the approximate curve represented by the equation M1 is ΔV1 ′,
ΔV1 ′ = C1− (a1I1 ′²+ B1I1 ′ + C1) = (R + Rpol2) I1 ′
And when this equation is organized,
-(A1I1 '+ B1) = R + Rpol2
The current I1 ′ at point A ′ is
I1 ′ = − (b1 + R + Rpol2) / a1
It becomes. Since R + Rpol2 (= R + Rpol1 ′) = ΔV2 / I2 (= ΔV1 ′ / I1 ′),

It becomes. Further, the voltage V1 'at the point A' is apparent from the above equation,
V1 '= a1I1'²+ B1I1 '+ C1
Therefore, the coordinates (I1 ′, V1 ′) of the point A ′ are determined from known values.
[0076]
Similarly, the current I2 ′ and the voltage V2 ′ at the point B ′ having a value equal to the resistance value (R + Rpol1) of the point A with respect to the point A are

Can be calculated from known values. Note that ΔV2 ′ is a voltage drop from the intercept C2 to the point B ′ with respect to the vertical axis of the approximate curve represented by Equation 2.
[0077]
When the coordinates (I1 ′, V1 ′) of the point A ′ are determined as described above, the coordinates (I1 ′, V1 ′) of the point A ′ and the coordinates (I2, V2) of the point B are obtained as shown in FIG. ), The combined resistance value R1 is obtained. The value R1 of the combined resistance is obtained by dividing the voltage drop difference (V1′−V2) caused by the combined resistance composed of the pure resistance and the polarization resistance component Rpol2 by the difference in current flowing at each point (I1′−I2). Sought by. That is,
R1 = (V1′−V2) / (I1′−I2)
It becomes.
[0078]
Similarly, when the coordinates (I2 ′, V2 ′) of the point B ′ are determined, the coordinates (I2 ′, V2 ′) of the point B ′ and the coordinates (I1, V1) of the point A are obtained as shown in FIG. The value R2 of the combined resistance is obtained by obtaining the slope of the straight line L2 connecting the two. The value R2 of this combined resistance is obtained by dividing the voltage drop difference (V1-V2 ') caused by the combined resistance composed of the pure resistance and the polarization resistance component Rpol1 by the difference in current flowing at each point (I1-I2'). Sought by. That is,
R2 = (V1-V2 ') / (I1-I2')
It becomes.
[0079]
However, the combined resistance values R1 and R2 obtained as described above are obtained by dividing the voltage drop difference caused by the combined resistance composed of the pure resistance and the polarization resistance component by the difference in current flowing at each point. Therefore, it does not match the pure resistance. In order to make the slope between the two points coincide with the pure resistance, the voltage drop difference excluding the voltage drop caused by the polarization resistance component may be divided by the current difference.
[0080]
First, the case where the point B is used as a reference will be described.
R1 = R1 ′ + Rpol2 = R1 ′ + Rpol1 ′
Then, a voltage drop caused by a current corresponding to the difference between the current I1 ′ at the point A ′ and the current I2 at the point B flowing through the resistor R1 ′ causes the polarization resistance component Rpol1 ′ (or Rpol2) to What is necessary is just to raise and correct the voltage at the point A ′ by the voltage drop caused by the current corresponding to the difference between the current I1 ′ and the current I2 at the point B, and the following equation is established.
R1 '(I1'-I2) = [V1' + Rpol1 '(I1'-I2)]-V2
[0081]
Organizing this formula,
R1 ′ (I1′−I2) = (V1′−V2) + Rpol1 ′ (I1′−I2). Here, since Rpol1 ′ = ΔV1 ′ / I1′−R1 ′,
R1 ′ (I1′−I2) = (V1′−V2) + (ΔV1 ′ / I1′−R1 ′) (I1′−I2)
2R1 ′ (I1′−I2) = (V1′−V2) + ΔV1 ′ / I1 ′ (I1′−I2)
And as a result,
R1 ′ = [(V1′−V2) + (ΔV1 ′ / I1 ′) (I1′−I2)] / 2 (I1′−I2)
Is required. Note that (ΔV1 ′ / I1 ′) can be replaced with (ΔV2 / I2).
[0082]
Next, when point A is used as a reference, the same applies.
R2 = R2 ′ + Rpol1 = R2 ′ + Rpol2 ′
Then, a voltage drop caused by a current corresponding to the difference between the current I1 at the point A and the current I2 ′ at the point B ′ flowing through the resistor R2 ′ causes a current at the point A in the polarization resistance component Rpol12 ′ (or Rpol1). The voltage at the point B ′ may be corrected by reducing the voltage drop caused by the current corresponding to the difference between the current I1 and the current I2 ′ at the point B ′, and the following equation is established.
R2 '(I1-I2') = V1- [V2'-Rpol2 '(I1-I2')]
[0083]
Organizing this formula,
R2 '(I1-I2') = (V1-V2 ') + Rpol2' (I1-I2 '). Here, since Rpol2 ′ = ΔV2 ′ / I2′−R2 ′,
R2 '(I1-I2') = (V1-V2 ') + (. DELTA.V2' / I2'-R2 ') (I1-I2')
2R2 ′ (I1−I2 ′) = (V1−V2 ′) + ΔV2 ′ / I2 ′ (I1−I2 ′)
And as a result,
R2 '= [(V1-V2') + (. DELTA.V2 '/ I2') (I1-I2 ')] / 2 (I1-I2')
Is required. Note that (ΔV2 ′ / I2 ′) can be replaced with (ΔV1 / I1).
[0084]
The two values R1 ′ and R2 ′ obtained as described above are based on the two points A and B, use different polarization resistance components (Rpol1 ′ = Rpol2) and (Rpol1 = Rpol2 ′), and have different intercepts. Since the voltage drop Δ1 ′ (ΔV1) from C1 and the voltage drop Δ2 ′ (ΔV2) from the intercept C2 are obtained, a true pure resistance R cannot be obtained. Therefore, the average of both
R = (R1 ′ + R2 ′) / 2
As a result, a true pure resistance R is obtained.
[0085]
Therefore, a method for measuring pure resistance will be described first with reference to FIGS. When a load that requires a large current, such as a starter motor, motor generator, or traveling motor, is installed in the vehicle to supply power to the vehicle load, the battery monotonously increases beyond a predetermined value. However, a discharge current that monotonously decreases from the maximum value to a predetermined value or less flows. By sampling the battery terminal voltage and discharge current at this time, for example, at a period of 1 ms, a large number of sets of battery terminal voltage and discharge current are obtained.
[0086]
The latest set of battery terminal voltage and discharge current obtained in this manner is stored, stored and collected in a memory as a rewritable storage means such as a RAM for a predetermined time. For example, V1 (I) of the voltage-current characteristic with respect to the increasing discharge current indicating the correlation between the terminal voltage and the discharge current by the least square method using the set of the terminal voltage and the discharge current stored, stored and collected in the memory. ) = A1I²A first approximate curve formula M1 expressed by a quadratic formula of + b1 + C1 and a voltage-current characteristic with respect to a decreasing discharge current, for example, V2 (I) = a2I²A second approximate curve equation M2 expressed by a quadratic equation + b2I + C2 is obtained.
[0087]
Next, the first point A on the voltage-current characteristic curve represented by the first approximate curve equation M1, and the second point on the voltage-current characteristic curve represented by the second approximate curve equation M2. Each B is defined. At this time, the first point A defined on the voltage-current characteristic curve represented by the first approximate curve equation M1 and the voltage-current characteristic curve represented by the second approximate curve equation M2 are determined. The second point B is preferably determined within a range in which actual data of the terminal voltage and the discharge current used when each approximate curve equation is obtained. By defining in this way, when assuming an assumed point corresponding to each point thereafter, the assumed point is not assumed to be greatly deviated. Preferably, the first point A and the second point B are determined on both sides of the point where the polarization resistance component is maximum. By defining in this way, the assumed points can be determined on both sides of the maximum point, and then the accuracy in obtaining the pure resistance is increased.
[0088]
Then, the second combined resistance R2 composed of the pure resistance of the battery and the second polarization resistance component Rpol2 that generates the second voltage drop ΔV2 when the second discharge current I2 corresponding to the second point B flows. When the first discharge current I1 corresponding to the first point A flows on the first assumed curve A ′ having the same resistance value as the first approximate curve equation M1, the first voltage drop ΔV1 is obtained. A second assumed point B ′ having the same resistance value as that of the first combined resistor R1 made of the pure resistance of the battery and the first polarization resistance component Rpol1 is assumed on the second approximate curve equation M2. .
[0089]
If the two assumed points A ′ and B ′ can be assumed, the first slope R1 of the straight line L1 connecting the second point B and the first assumed point A ′ is set to the second discharge current I2 and the first After correcting the difference Rpol2 (I1′−I2) of the voltage drop caused by the second polarization resistance component Rpol2 generated by the discharge current I1 ′ at the assumed point A ′, the voltage drop caused by the second polarization resistance component Rpol2 The first corrected slope R1 ′ excluding the minute is obtained, and the second slope R2 of the straight line L2 connecting the first point and the second assumed point B ′ is determined as the first discharge current I1 and the second After correcting the voltage drop difference Rpol1 (I1-I2 ') caused by the first polarization resistance component Rpol1 generated by the discharge current I2' at the two assumed points B ', the first polarization resistance component Rpol1 Second correction excluding voltage drop Seek an oblique R2 '.
[0090]
The average inclination is obtained by averaging the first correction slope R1 'and the second correction slope R2' thus obtained, and the obtained average slope is measured as the pure resistance R of the battery.
[0091]
Next, specific contents of the pure resistance measurement process in step S3 in the flowchart of FIG. 3 performed by the CPU 23a according to the control program stored in the ROM 23c will be described with reference to FIG.
[0092]
The actual data for the latest predetermined time of the discharge current I and the terminal voltage V collected in step S2 in the flowchart of FIG. 3 is analyzed, and a second-order approximation of the voltage-current characteristic is applied by applying the least square method. A determination is made as to whether the curve equation is appropriate. That is, an analysis process is performed to analyze whether or not a discharge current that monotonously increases beyond a predetermined value and monotonously decreases from a maximum value to a predetermined value or less flows from the battery (step S21).
[0093]
As a result of the analysis in step S21, when the appropriate ones for obtaining the quadratic approximate curve equation of the voltage-current characteristic are collected (Y in step S22), V1 of the voltage-current characteristic with respect to the increasing discharge current ( I) = a1I²A first approximate curve formula M1 expressed by a quadratic formula of + b1 + C1 and a voltage-current characteristic with respect to a decreasing discharge current, for example, V2 (I) = a2I²An approximate curve equation calculation process for obtaining a second approximate curve equation M2 represented by a quadratic equation of + b2I + C2 is executed (step S23).
[0094]
After the two approximate curve equations M1 and M2 are obtained by the approximate curve equation calculation processing in step S23, next, calculation processing for obtaining the pure resistance of the battery is executed (step S24). In the calculation process in step S24, the pure resistance of the battery and the second polarization resistance that cause a voltage drop when a discharge current corresponding to a point determined on the voltage-current characteristic curve represented by the approximate curve equation M2 flows. A first assumed point having the same resistance value as the combined resistance composed of components is assumed on the voltage-current characteristic curve represented by the first approximate curve equation M1. Further, the battery comprises a pure resistance of the battery and a first polarization resistance component that cause a voltage drop when a discharge current corresponding to a point determined on the voltage-current characteristic curve represented by the first approximate curve equation M1 flows. A second assumption point having the same resistance value as the combined resistance is assumed on the voltage-current characteristic curve represented by the second approximate curve equation M2.
[0095]
In the calculation processing in step S24, the first slope of the straight line connecting the point defined on the voltage-current characteristic curve represented by the approximate curve equation M2 and the first assumed point is used as the second approximate curve equation. After correcting the difference in voltage drop due to the two polarization resistance components respectively generated by the discharge current corresponding to the point defined on the voltage-current characteristic curve represented by the above and the discharge current at the second assumed point, A first correction gradient excluding a voltage drop due to the second polarization resistance component is obtained.
[0096]
In the calculation processing in step S24, the second slope of the straight line connecting the point defined on the voltage-current characteristic curve represented by the approximate curve equation M1 and the second assumed point is further expressed as the first approximate curve equation. After correcting the difference in voltage drop due to one polarization resistance component generated by the discharge current corresponding to the point defined on the voltage-current characteristic curve represented by the above and the discharge current at the second assumed point, respectively, A second correction gradient excluding the voltage drop due to the first polarization resistance component is obtained. Then, the average inclination is obtained by averaging the first correction inclination and the second correction inclination obtained in step S24, and the average inclination is measured as the pure resistance of the battery. The measured pure resistance is used for various purposes. For use, it is stored and stored in the data area of the RAM 23b (step S25). When the measurement process in step S25 is completed, the determination in step S22 becomes Y, and the steps in the flowchart of FIG. 3 are executed until there is an opportunity to execute the approximate curve equation calculation process in step S23 and the calculation process in step S24. The collection process of S2 and the analysis process of step S21 are repeatedly executed.
[0097]
Further, in the vehicle battery pure resistance measuring apparatus 1 of the present embodiment, step S2 in the flowchart of FIG. 3 is processing for the voltage / current measuring means in the claims, and step S23 in the flowchart of FIG. 12 is in the claims. The approximate curve calculation means corresponds to the process, and step S24 is a process corresponding to the calculation means in the claims.
[0098]
Next, the pure resistance measurement operation (action) of this embodiment will be described.
[0099]
First, when an electrical component (load) other than the motor generator 5 of the hybrid vehicle is operated, or the motor generator 5 is operating so as to function as a motor, and the battery 13 is discharged accordingly, the load is applied. The battery terminal voltage and the discharge current are periodically measured when a discharge current that monotonously exceeds a predetermined value and monotonously decreases from the maximum value to a predetermined value or less flows.
[0100]
Further, the latest data measured periodically is stored in the data area of the RAM 23b for a predetermined time, collected and collected, and the collected actual data for the latest predetermined time of the discharge current I and the terminal voltage V is collected. Is analyzed and a least squares method is applied to determine whether it is appropriate for obtaining a quadratic approximate curve equation of the voltage-current characteristic. That is, it is analyzed whether or not a discharge current that monotonously increases beyond a predetermined value and monotonously decreases from a maximum value to a predetermined value or less flows from the battery.
[0101]
For this reason, the approximate curve formula calculation process is not performed until an appropriate curve equation for obtaining the quadratic approximate curve formula of the voltage-current characteristic is collected, and the approximate curve formula calculation process is also collected in the past. Since it suffices to use actual data for a predetermined time, processing does not have to be performed in synchronization with periodic measurement of the terminal voltage and the discharge current, and a high processing speed is not required.
[0102]
Furthermore, two points determined within the range in which the measured battery terminal voltage and discharge current exist are used in order to obtain the first approximate curve formula and the second approximate curve formula. As long as there is no hindrance in the relationship, it is not limited to this. However, in order to maintain accuracy, it is preferable to set within the range of the monotone increase of the first approximate curve equation or the monotone decrease of the second approximate curve equation.
[0103]
In the above-described embodiment, arbitrary points A and B are selected within a range where actual data exists on the approximate curves represented by the two approximate curve equations M1 and M2 of the VI characteristic. These points are selected on the two approximate curve equations M1 and M2 as the point P corresponding to the maximum value of the measured battery discharge current to obtain these equations, and both points are used with common data. Therefore, it is possible to reduce errors.
[0104]
[Second example]
Incidentally, 12V, 42V, EV, and HEV vehicles are equipped with loads that require large currents such as starter motors, motor generators, and traveling motors. As shown in FIG. 13, after supplying a large amount of current, called a rush current, at the beginning of the current flow, a rapidly increasing current flows, and then the current characteristic rapidly decreases to a steady current.
[0105]
When a load that requires a large current as described above is driven, a single discharge causes a discharge current that monotonously increases beyond a predetermined value and monotonously decreases from a maximum value to a predetermined value or less. When the terminal voltage and discharge current of the battery at this time are measured periodically and shown in a graph based on actual data indicating the correlation between the terminal voltage and the discharge current, discharge is started as shown in FIG. Two characteristics are a current increase VI characteristic with respect to a discharge current that rapidly increases to a predetermined value or more during a predetermined period in the increasing direction, and a current decrease VI characteristic with respect to a discharging current in which the current reaches a maximum and then decreases in the decreasing direction. can get. The difference between these two characteristics is analyzed below.
[0106]
On the other hand, in the case of the current increase VI characteristic with respect to the discharge current that rapidly increases to a predetermined value of, for example, 200A to 250A within a predetermined period of several milliseconds, for example, the discharge resistance is determined based on the polarization resistance component at the discharge start time. Even when the current starts and the current increases, the rate of current increase is much faster than the rate of generation of the polarization resistance component, so even if the discharge current reaches its peak, a polarization resistance component corresponding to the magnitude of the current is generated. However, the ratio of the voltage drop due to the polarization resistance component occupying the voltage drop of the terminal voltage generated by the current flowing is extremely small, most of which is due to the pure resistance component.
[0107]
This becomes more apparent by analyzing the other current decrease VI characteristic. That is, after the current reaches the maximum value, the polarization resistance component should disappear as the current decreases, but in reality, the polarization resistance component does not disappear in proportion to the decrease in current. Rather, it will increase. This is because the polarization resistance component is generated at a low speed, and therefore increases even if the current decreases. When a polarization resistance component corresponding to a certain current on the current decrease VI characteristic is generated, the voltage is increased. The voltage drop due to the polarization resistance component occupying during the drop is the maximum ratio. Eventually, the polarization resistance component corresponding to the steady-state current is eliminated with a delay as the current decreases, and the polarization resistance is maintained even when the current becomes zero until the polarization resistance component is completely eliminated. The voltage drop of the battery terminal voltage due to the component remains.
[0108]
As described above, the terminal voltage of the battery when a discharge current that suddenly increases above a predetermined value flows in a predetermined period is almost the voltage that reflects the voltage drop caused by the discharge current flowing through the pure resistance of the battery. Focusing on the fact that the voltage due to the polarization resistance component hardly appears, a method of measuring the pure resistance R of the battery using the current increase VI characteristic of the two VI characteristics described above is shown in FIG. A specific description will be given below with reference to FIGS.
[0109]
The terminal voltage of the battery and the discharge current when the discharge current flows through a load that requires a large current such as a starter motor, a motor generator, or a traveling motor mounted on the vehicle, for example, a relatively fast cycle of 1 millisecond, for example. Based on the terminal voltage and discharge current obtained by this measurement, the variations ΔV and ΔI per unit time ΔT between the terminal voltage V and the discharge current I are obtained. Subsequently, a value obtained by dividing the obtained change amount ΔV of the terminal voltage V by the change amount ΔI of the discharge current I is measured as a pure resistance R.
[0110]
In obtaining the change amount per unit time of the terminal voltage and the discharge current, the change amount ΔV of the terminal voltage V is discharged by detecting that the discharge current increases by a predetermined value or more in a predetermined period. It is guaranteed that the accuracy of the pure resistance R measured by the value obtained by dividing by the change amount ΔI of the current I falls within a predetermined range. That is, in the case of a discharge current that increases more than a predetermined value in a predetermined period, the occurrence of polarization is very small and the voltage drop due to its resistance component is so small that it can be ignored compared to that due to pure resistance, The accuracy comes within a predetermined range. In addition, by detecting in advance that the discharge current increases by a predetermined value or more in a predetermined period, if this condition is not met, the amount of change per unit time between the terminal voltage and the discharge current is obtained. There is no need to do this, and wasteful processing can be eliminated.
[0111]
In addition, when detecting that the discharge current is increased by a predetermined value or more in a predetermined period, the battery terminal voltage and the discharge current measured periodically are collected, stored, and stored for at least the latest predetermined period. . Based on the stored terminal voltage and discharge current for the latest predetermined period stored, when it is detected that the discharge current is increased by a predetermined value or more in the predetermined period, the latest stored Based on the terminal voltage and the discharge current for a predetermined period, the terminal voltage and the discharge current within the predetermined period are used to obtain the amount of change per unit time between the terminal voltage and the discharge current. Processing can be performed at the time.
[0112]
Specifically, for example, when a load that requires a large current, such as a starter motor, a motor generator, or a traveling motor, is operated, the battery monotonically increases beyond a predetermined value and monotonously decreases from a maximum value to a predetermined value or less. Discharge current flows. By sampling the terminal voltage and discharge current of the battery at this time, for example, at a period of 1 ms, many pairs of the terminal voltage and discharge current of the battery are obtained by periodically measuring.
[0113]
The latest set of the battery terminal voltage and discharge current obtained in this way is stored, stored and collected in a memory as a rewritable storage means such as a RAM for a predetermined period, for example. Using a set of terminal voltage and discharge current stored, stored and collected in a memory, it is detected that the discharge current increases by a predetermined value or more in a predetermined period, and the discharge current increases by a predetermined value or more in a predetermined period When it is detected that it is to be, the amount of change per unit time between the terminal voltage and the discharge current is obtained using a set of the terminal voltage and the discharge current collected and stored in the memory. Then, a value obtained by dividing the obtained change amount of the terminal voltage by the change amount of the discharge current is measured as a pure resistance of the battery.
[0114]
Next, specific contents of the pure resistance measurement process in step S3 in the flowchart of FIG. 3 performed by the CPU 23a according to the control program stored in the ROM 23c will be described with reference to the flowchart of FIG.
[0115]
The actual data for the latest predetermined time of the discharge current I and the terminal voltage V collected in step S2 in the flowchart of FIG. 3 is analyzed to determine whether a discharge current that monotonously increases beyond a predetermined value flows from the battery. An analysis process is performed (step S31).
[0116]
As a result of the analysis in step S31, those suitable for obtaining the voltage-current characteristics are collected, and it is determined whether or not the discharge current has increased by a predetermined value or more in a predetermined period (step S332). When the discharge current is increased by a predetermined value or more during a predetermined period (Y in step S32), that is, when it is detected that the discharge current is increased by a predetermined value or more during the predetermined period, The change amounts ΔI and ΔV per unit time between the discharge current I and the terminal voltage V collected in step S33 are obtained (step S33).
[0117]
When the changes ΔI and ΔV per unit time between the discharge current I and the terminal voltage V are obtained in step S33, the value obtained by dividing the change ΔV of the terminal voltage by the change ΔI of the discharge current is then obtained. Measurement is made as the pure resistance R (step S34), and the measured pure resistance is stored and stored in the data area of the RAM 23b for use for various purposes (step S35). When the determination in step S32 is N, the process returns to step S2 in FIG. 3 to collect the latest predetermined time actual data of the discharge current I and the terminal voltage V. As a result of the analysis in step S31, Until the determination is Y, steps S2 to S32 described above are repeated.
[0118]
Further, step S2 in the flowchart of FIG. 3 is processing for the voltage / current measuring means 23a-15 in the claims, and step S32 is processing corresponding to the current increase detecting means 23a-161 in the claims. Step S33 is processing corresponding to the change amount calculation means 23a-16 in the claims, and step S34 is the division means 23a-17 in the claims.
[0119]
Next, the pure resistance measurement operation (action) will be described.
[0120]
First, when an electrical component (load) other than the motor generator 5 of the hybrid vehicle is operated, or when the motor generator 5 is operated so as to function as a motor, the battery 13 starts discharging in accordance with the electric component (load). A discharge current that monotonously increases to a predetermined value or more and monotonously decreases from the maximum value to reach a steady state flows, and at least the terminal voltage and the discharge current of the battery at this time are periodically measured. Of course, the terminal voltage and discharge current of the battery may be measured periodically.
[0121]
The latest data measured periodically is stored in the data area of the RAM 23b for a predetermined period, stored and collected, and the collected actual data of the discharge current I and the terminal voltage V for the latest predetermined period. Accordingly, it is analyzed whether or not a discharge current increased by a predetermined value or more has flowed from the battery in a predetermined period.
[0122]
Therefore, the pure resistance measurement process is not performed until an appropriate one is collected, and the pure resistance measurement process may be performed using actual data for a predetermined period collected in the past. The processing does not have to be performed in synchronization with the periodic measurement of the discharge current, and a high processing speed is not required.
[0123]
Further, it is preferable that the predetermined period and the predetermined value are arbitrarily determined as long as the presence of the discharge current increased by a predetermined value or more in the predetermined period does not hinder the relationship with the required accuracy.
[0124]
In the above example, the case where an electrical component (load) other than the motor generator 5 is activated as a load is described. However, in a state where a constant discharge current flows in a steady state, the load is operated by an operation of an arbitrary load. When a discharge current that exceeds a predetermined value flows within a predetermined period, such as a rush current at the start of operation, the voltage drop of the terminal voltage that accompanies this increase in discharge current can be regarded as being caused by a pure resistance. The pure resistance is measured by dividing the change amount of the terminal voltage generated in this short time by the change amount of the discharge current.
[0125]
In the above-described embodiment, the monotonically increasing discharge current section of the discharge current flowing through the load is used for measuring the pure resistance. However, a current change of a predetermined value or more is detected within a predetermined period. If so, a monotonically decreasing discharge current may be used to measure the pure resistance.
[0126]
In the above-described embodiment, the pure resistance of the battery is measured using the discharge current flowing through the load. However, when the charging current for charging the battery changes by a predetermined value or more within a predetermined period. Can also use this charging current for pure resistance measurement.
[0127]
That is, when measuring the net resistance of the battery mounted on the vehicle to supply power to the load mounted on the vehicle, the terminal voltage and the charging current of the battery when the charging current flows into the battery are periodically Based on the terminal voltage and charging current obtained by measurement, when the charging current that is obtained by measurement and increases rapidly over a predetermined value flows in a predetermined period, the change per unit time of the terminal voltage and charging current The value obtained by dividing the obtained change amount of the terminal voltage by the change amount of the charging current can be measured as the pure resistance of the battery.
[0128]
As used herein, the term “pure resistance” does not mean true ohmic resistance, but includes resistance components other than ohmic resistance, but is included only to a negligible extent. , Which is very close to true ohmic resistance.
[0129]
【The invention's effect】
As described above, according to the first or ninth aspect of the invention, the measured battery pure resistance and the predetermined unused time corresponding to the state of charge when the pure resistance is measured.InPure resistance and predetermined lifetimeInBased on net resistance andMountedCalculate and determine the degree of deterioration of the battery.MountedSince the deterioration degree of the battery can be automatically determined, it is possible to provide a vehicle battery deterioration degree determination method and apparatus capable of determining the deterioration degree of the battery during use of the vehicle.
[0130]
According to the invention described in

claim

2 or 10 described above, the degree of deterioration is obtained as a percentage, and the progress of deterioration can be objectively grasped by specific numerical values. Therefore, it is possible to provide a method and an apparatus for determining the degree of deterioration of a battery for a vehicle, which eliminates the need to do so and has a low determination error and high reliability.
[0131]
According to the invention described in

claim

3 or 11, the data obtained as a result of the measurement of the battery terminal voltage and the discharge current when power is supplied to the load in the normal use state of the vehicle is processed to obtain two data. Since an approximate curve is obtained and the degree of deterioration of the battery is determined based on the pure resistance of the battery obtained by using the slope of a straight line connecting two points where the polarization resistance components on the two approximate curves are equal, the vehicle is being used. It is possible to provide a vehicle battery deterioration degree determination method and apparatus capable of determining the deterioration degree of a battery.
[0132]
According to the invention described in claim 4 or 12, the battery terminal voltage and the discharge current measured in order to obtain the approximate curve expression when the pure resistance of the battery is obtained using the two approximate curves are within a range where the battery terminal voltage and the discharge current exist. By selecting one of the two points and eliminating the use of a point that deviates greatly from the actual value, it is possible to keep the measurement accuracy of the pure resistance stable, and a battery that uses this is used. It is possible to provide a vehicle battery deterioration degree determination method and apparatus capable of accurately determining the deterioration degree of the vehicle battery.
[0133]
According to the invention described in

claim

5 or 13, the stored actual data is used to confirm that the discharge current necessary for obtaining the approximate curve formula has flowed, and then the stored actual data is used. Therefore, it is possible to obtain an approximate curve equation, eliminate unnecessary processing, and eliminate real-time high-speed processing. And an apparatus can be provided.
[0134]
According to the invention described in claim 6 or 14, the polarization generated by the discharge current increased per unit time is very small, and the change amount of the terminal voltage, that is, the ratio of the polarization resistance component to the voltage drop is extremely small. The value obtained by dividing the amount of change in the terminal voltage by the amount of change in the discharge current is measured as the pure resistance of the battery, and the pure resistance of the battery that can be measured even when the vehicle is in use. Therefore, it is possible to provide a vehicle battery deterioration degree determination method and apparatus that can determine the battery deterioration degree even during use of the vehicle.
[0135]
According to the above-described invention according to

claim

7 or 15, since the accuracy of the measured pure resistance can always be within a predetermined range, the determination of the degree of deterioration using this can be kept stable. It is possible to provide a method and apparatus for determining the degree of deterioration of a vehicle battery.
[0136]
According to the invention described in claim 8 or 16, the processing for obtaining the pure resistance can be performed at any convenient time, and unnecessary processing is omitted, and measurement is performed without performing real-time high-speed processing. Since a pure resistance that can be used is used, it is possible to provide a method and an apparatus for determining the degree of deterioration of a vehicle battery that can determine the degree of deterioration with flexibility.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a basic configuration of a vehicle battery deterioration degree determination apparatus according to the present invention.
FIG. 2 is an explanatory diagram partially showing a schematic configuration of a vehicle battery deterioration degree determination apparatus according to an embodiment of the present invention to which the vehicle battery deterioration degree determination method of the present invention is applied.
FIG. 3 is a flowchart showing processing performed by the microcomputer in FIG. 2 according to a predetermined program for determining the degree of deterioration of the battery.
FIG. 4 is a graph showing a change in pure resistance with respect to a charged state of a battery when not in use and at the time of life.
FIG. 5 is a graph showing an example of a VI characteristic represented by a first-order approximation expression.
FIG. 6 is a graph showing an example of a VI characteristic represented by a quadratic approximate curve equation.
FIG. 7 is a graph showing an example of voltage change due to polarization with respect to current.
FIG. 8 is a graph showing an example of an approximate characteristic curve represented by two quadratic approximate curves obtained by one discharge.
FIG. 9 is a graph for explaining how to determine two arbitrary points on two approximate characteristic curves;
FIG. 10 is a graph for explaining how to determine an assumed point with respect to a point determined on one approximate characteristic curve and how to correct an inclination between two points.
FIG. 11 is a graph for explaining how to determine an assumed point with respect to a point determined on the other approximate characteristic curve and how to correct an inclination between two points.
12 is a flowchart showing processing performed by the microcomputer in FIG. 2 according to a predetermined program for pure resistance measurement.
FIG. 13 is a graph showing current characteristics of a large current load.
14 is a graph showing VI characteristics when the current characteristics shown in FIG. 12 are used. FIG.
FIG. 15 is a graph showing current characteristics for explaining the present invention.
FIG. 16 is a graph showing current increase VI characteristics for explaining the present invention;
FIG. 17 is a flowchart showing processing performed by the microcomputer in FIG. 2 in accordance with a predetermined program for pure resistance measurement.
[Explanation of symbols]
23a-1 Pure resistance measurement and measurement means (CPU)
23a-2 Deterioration degree calculation determination means (CPU)
23a-11 Voltage / current measuring means (CPU)
23a-12 Approximate curve formula calculation means (CPU)
23a-13 Calculation means (CPU)
23a-15 Voltage / current measuring means (CPU)
23a-16 Change amount calculation means (CPU)
23a-161 Current increase detection means (CPU)
23a-17 Division means (CPU)
23b-1 Pure resistance memory means (RAM)
23b-2 Storage means (RAM)
23b-3 Storage means (RAM)

Claims

In a vehicle battery deterioration degree determination method for determining a deterioration degree of a battery mounted on a vehicle to supply power to a load mounted on the vehicle,
A pure resistance of the battery corresponding to a charging state when the battery corresponding to the mounted battery is not used and a pure resistance of the battery corresponding to the charging state at the time of life are respectively determined in advance.
A terminal voltage and a discharge current of the battery obtained by periodically measuring when a discharge current flows from the mounted battery to the load, which monotonously increases beyond a predetermined value and monotonously decreases from a maximum value to a predetermined value or less. Based on the above , measure the pure resistance of the mounted battery,
A pure resistance was the measurement, based on the pure resistance at the pure resistor and the predetermined life in the non-use of the predetermined corresponding to the state of charge of the onboard battery when measuring the pure resistance A method for determining the degree of deterioration of a vehicle battery, comprising: calculating and determining a degree of deterioration of the mounted battery.

The vehicle battery deterioration degree determination method according to claim 1,
The degree of deterioration is determined by a percentage of a value obtained by dividing a difference between the measured pure resistance and the pure resistance when not used by a difference between the pure resistance at the time of life and the pure resistance when not used. A vehicle battery battery deterioration degree determination method.

In the method for determining the degree of deterioration of the vehicle battery according to claim 1 or 2,
The terminal voltage and discharge current of the battery are periodically measured when a discharge current that monotonously increases beyond a predetermined value and monotonically decreases from a maximum value to a predetermined value or less flows to the load. A first approximate curve equation of voltage-current characteristics for the increasing discharge current and a second approximate curve equation of voltage-current characteristics for the decreasing discharge current,
A first point is defined on the voltage-current characteristic curve represented by the first approximate curve formula, and a second point is defined on the voltage-current characteristic curve represented by the second approximate curve formula, respectively.
When the second discharge current corresponding to the second point flows, a second voltage drop is generated, and the resistance value is the same as the second combined resistance composed of the pure resistance of the battery and the second polarization resistance component. A first voltage drop occurs when a first discharge current corresponding to the first point flows on the voltage-current characteristic curve represented by the first approximate curve equation with the first assumed point having The second assumed point having the same resistance value as the first combined resistance composed of the pure resistance of the battery and the first polarization resistance component is represented on the voltage-current characteristic curve expressed by the second approximate curve equation. Assuming that
The second polarization in which a first slope of a straight line connecting the second point and the first assumption point is generated by the second discharge current and the discharge current at the first assumption point, respectively. After correcting the difference in voltage drop due to the resistance component, the first correction slope excluding the voltage drop due to the second polarization resistance component is obtained, and the first point and the second assumed point are obtained. After correcting the difference in voltage drop caused by the first polarization resistance component, which is caused by the first discharge current and the discharge current at the second assumed point, respectively, the second slope of the connecting straight line is corrected. The second correction slope excluding the voltage drop due to the polarization resistance component of 1 is obtained,
A method for determining a deterioration level of a vehicle battery, comprising: averaging the obtained first and second inclinations to obtain an average inclination, and measuring the obtained average inclination as the pure resistance of the battery.

The vehicle battery deterioration degree determination method according to claim 3,
The first point and the second point are determined within a range in which the terminal voltage and discharge current of the battery measured to obtain the first approximate curve equation and the second approximate curve equation exist. A method for determining a deterioration level of a vehicle battery, comprising:

In the vehicle battery deterioration degree determination method according to claim 3 or 4,
In obtaining the first approximate curve equation and the second approximate curve equation, the terminal voltage and discharge current of the battery measured periodically are collected, stored and stored for the latest predetermined time. A method for determining a deterioration level of a vehicle battery, comprising:

In the method for determining the degree of deterioration of the vehicle battery according to claim 1 or 2,
Obtained by periodically measuring the terminal voltage and discharge current of the battery when a discharge current flows through the load,
Based on the terminal voltage and discharge current obtained by the measurement when a discharge current that rapidly increases to a predetermined value or more flows in a predetermined period, obtain the amount of change per unit time of the terminal voltage and discharge current,
A method for determining a deterioration level of a vehicle battery, wherein a value obtained by dividing the obtained change amount of the terminal voltage by the change amount of the discharge current is measured as a pure resistance of the battery.

The vehicle battery deterioration degree determination method according to claim 6,
In determining the amount of change per unit time between the terminal voltage and the discharge current, it is detected that the discharge current increases by a predetermined value or more in a predetermined period, and a deterioration degree determination method for a vehicle battery, .

The vehicle battery deterioration degree determination method according to claim 7,
In detecting that the discharge current increases by a predetermined value or more in a predetermined period, the terminal voltage and the discharge current of the battery measured periodically are collected, stored and stored for at least the latest predetermined period. Every
Based on the stored terminal voltage and discharge current for the latest predetermined period, when it is detected that the discharge current has an increase of a predetermined value or more in the predetermined period, the terminal voltage within the predetermined period A method for determining a degree of deterioration of a vehicle battery, wherein the amount of change per unit time is obtained from a discharge current.

In a vehicle battery deterioration degree determination device for determining a deterioration degree of a battery mounted on a vehicle in order to supply electric power to a load mounted on the vehicle,
A terminal voltage and a discharge current of the battery obtained by periodically measuring when a discharge current flows from the mounted battery to the load, which monotonously increases beyond a predetermined value and monotonously decreases from a maximum value to a predetermined value or less. On the basis of the pure resistance measuring means for measuring the pure resistance of the mounted battery,
Pure resistance storage means for preliminarily storing the battery pure resistance corresponding to the state of charge when the battery corresponding to the mounted battery is not used and the battery pure resistance corresponding to the state of charge at the end of life, respectively;
Wherein a pure resistance measured by a pure resistance measuring means, the net in the onboard when not in use of the battery which has been previously stored in the pure resistance storage means corresponding to the state of charge of the battery when measuring the pure resistance A deterioration degree determination device for a vehicle battery, comprising: a deterioration degree calculation determination unit that calculates and determines a deterioration degree of the mounted battery based on a resistance and a pure resistance at the time of life.

In the vehicle battery deterioration degree determination apparatus according to claim 9,
The deterioration degree calculation determining means divides the deterioration degree by dividing a difference between the measured pure resistance and the pure resistance when not in use by a difference between the pure resistance at the end of life and the pure resistance when not in use. An apparatus for determining a deterioration level of a vehicle battery, characterized in that it is obtained as a percentage of the measured value.

In the vehicle battery deterioration degree determination apparatus according to claim 9 or 10,
The pure resistance measuring means includes
Voltage / current measuring means for periodically measuring the terminal voltage and discharge current of the battery when a discharge current that monotonously increases beyond the predetermined value and monotonically decreases from the maximum value to a predetermined value or less flows to the load;
A first approximate curve expression of the voltage-current characteristic for the increasing discharge current and a second of the voltage-current characteristic for the decreasing discharge current showing the correlation between the terminal voltage measured by the voltage / current measuring means and the discharge current. An approximate curve formula calculating means for obtaining an approximate curve formula of
A pure resistance of the battery that causes a second voltage drop when a second discharge current corresponding to a second point defined on the voltage-current characteristic curve represented by the second approximate curve equation flows; A first assumption point having the same resistance value as the second combined resistance composed of the second polarization resistance component is placed on the voltage-current characteristic curve represented by the first approximate curve formula, and the first approximation. The pure resistance of the battery and the first polarization resistance component that cause the first voltage drop when the first discharge current corresponding to the first point defined on the voltage-current characteristic curve represented by the curve equation flows A second assumed point having the same resistance value as the first combined resistor is assumed on the voltage-current characteristic curve represented by the second approximate curve equation, and the second point and the second The first slope of a straight line connecting the first assumed point is defined as the second discharge current. And the difference between the voltage drops due to the second polarization resistance component, which are respectively generated by the discharge current at the first assumption point, and the first drop after removing the voltage drop due to the second polarization resistance component. And a second slope of a straight line connecting the first point and the second assumed point is determined by the first discharge current and the discharge current at the second assumed point, respectively. After correcting the difference in voltage drop caused by the first polarization resistance component, a second correction slope excluding the voltage drop due to the first polarization resistance component is obtained, and the obtained first correction is obtained. A calculating means for calculating an average inclination by averaging the inclination and the second correction inclination;
An apparatus for determining a degree of deterioration of a vehicle battery, wherein the average inclination obtained by the computing means is measured as the pure resistance of the battery.

In the vehicle battery deterioration degree determination apparatus according to claim 11,
The computing means includes the terminal voltage of the battery and the discharge current measured for obtaining the first approximate curve equation and the second approximate curve equation for the first point and the second point. An apparatus for determining a deterioration level of a vehicle battery, characterized by being determined within a range.

In the vehicle battery deterioration degree determination apparatus according to claim 11 or 12,
The approximate curve equation calculating means obtains the terminal voltage and discharge current of the battery periodically measured by the voltage / current measuring means in order to obtain the first approximate curve equation and the second approximate curve equation. A vehicle battery deterioration degree determination device comprising storage means for collecting, storing and storing the latest predetermined time.

In the vehicle battery deterioration degree determination apparatus according to claim 9 or 10,
The pure resistance measuring means includes
Voltage / current measuring means obtained by periodically measuring the terminal voltage and discharge current of the battery when a discharge current flows through the load;
Based on the terminal voltage and the discharge current obtained by the voltage / current measuring means when a discharge current that suddenly increases above a predetermined value flows in a predetermined period, the terminal voltage and the discharge current change per unit time A change amount calculating means for obtaining an amount;
Division means for dividing the change amount of the terminal voltage obtained by the change amount calculation means by the change amount of the discharge current;
An apparatus for determining a deterioration level of a vehicle battery, characterized in that a value obtained by the dividing means is measured as a pure resistance of the battery.

In the vehicle battery deterioration degree determination device according to claim 14,
The change amount calculation means includes current increase detection means for detecting that the discharge current increases by a predetermined value or more in a predetermined period when obtaining the change amount per unit time between the terminal voltage and the discharge current. An apparatus for determining a deterioration level of a vehicle battery.

The vehicle battery deterioration degree determination device according to claim 15,
The change amount calculating means collects at least the latest predetermined period of the terminal voltage and the discharge current of the battery measured periodically when detecting that the discharge current increases by a predetermined value or more during a predetermined period. Storage means for storing and storing, and based on the latest terminal voltage and discharge current for a predetermined period stored in the storage means, the current increase detection means determines that the discharge current is predetermined. A deterioration degree determination device for a vehicle battery, characterized in that, when it is detected that there is an increase over a predetermined value in a period, a change amount per unit time is obtained from a terminal voltage and a discharge current within the predetermined period. .