JP2004134221A

JP2004134221A - Overcharge/overdischarge monitoring device for battery pack

Info

Publication number: JP2004134221A
Application number: JP2002297192A
Authority: JP
Inventors: Toyoaki Nakagawa; 中川　豊昭; Makoto Iwashima; 岩島　誠; Tetsuya Niiguni; 新国　哲也
Original assignee: Nissan Motor Co Ltd
Current assignee: Nissan Motor Co Ltd
Priority date: 2002-10-10
Filing date: 2002-10-10
Publication date: 2004-04-30
Anticipated expiration: 2022-10-10
Also published as: JP4069720B2

Abstract

<P>PROBLEM TO BE SOLVED: To enhance monitoring contents and take the optimum action as a system. <P>SOLUTION: When an overdischarge state of either cell constituting a battery pack is detected, if the overdischarge state of the battery pack is detected, an abnormal signal of the battery pack is not outputted, and a discharge inhibiting signal is outputted. When the overdischarge state of either cell constituting the battery pack is detected, if the overdischarge state of the battery pack is not detected, the abnormal signal of the battery pack is outputted. When the overcharge state of either cell constituting the battery pack is detected, if the overcharge state of the battery pack is detected, the abnormal signal of the battery pack is not outputted and a charge inhibiting signal is outputted. When the overcharge state of the battery pack is detected, if the overcharge state of the battery pack is not detected, the abnormal signal of the battery pack is outputted. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、組電池の過充電状態および過放電状態を監視する装置に関する。
【０００２】
【従来の技術】
複数の単電池（以下、セルと呼ぶ）が直列に接続された組電池において、複数のセルの内のいずれかが過充電状態または過放電状態になったことを検知する監視装置が知られている（例えば、特許文献１参照）。
【０００３】
この出願の発明に関連する先行技術文献としては次のものがある。
【特許文献１】
特開平０５−２５８７７８号公報
【０００４】
【発明が解決しようとする課題】
しかしながら、従来の組電池の過充放電監視装置では、いずれかのセルの過充電状態または過放電状態を検知しているのみであり、監視内容が乏しく、システムとしての最適な対応がとれないという問題がある。
【０００５】
本発明の目的は、監視内容の充実を図り、システムとして最適な対応がとれるようにすることにある。
【０００６】
【課題を解決するための手段】
本発明は、組電池を構成するいずれかのセルまたはセル並列回路の過放電状態が検出されたときに、組電池の過放電状態が検出された場合は、組電池異常信号を出力せず、放電禁止信号を出力する。一方、組電池を構成するいずれかのセルまたはセル並列回路の過放電状態が検出されたときに、組電池の過放電状態が検出されていない場合は、組電池異常信号を出力する。
また、本発明は、組電池を構成するいずれかのセルまたはセル並列回路の過充電状態が検出されたときに、組電池の過充電状態が検出された場合は、組電池異常信号を出力せず、充電禁止信号を出力する。一方、組電池を構成するいずれかのセルまたはセル並列回路の過充電状態が検出されたときに、組電池の過充電状態が検出されていない場合は、組電池異常信号を出力する。
さらに、本発明は、組電池を構成するいずれかのセルまたはセル並列回路の過充電状態または過放電状態が検出されたときに、組電池の充放電可能な正常な状態が検出されない場合は、組電池異常信号を出力せず、充放電禁止信号を出力する。一方、組電池を構成するいずれかのセルまたはセル並列回路の過充電状態または過放電状態が検出されたときに、組電池の充放電可能な正常な状態が検出された場合は、組電池異常信号を出力する。
【０００７】
【発明の効果】
本発明によれば、監視内容の充実を図ることができ、システムとして最適な対応をとることができる。
【０００８】
【発明の実施の形態】
セル（単電池）をｎ個直列に接続した組電池に対して本願発明を適用した一実施の形態を説明する。なお、本願発明は、セルを複数個直列に接続した組電池に限定されず、複数のセルを並列に接続したセル並列回路を複数組直列に接続した組電池に対しても適用することができる。また、本願発明は、電池の種類について特に限定されるものではなく、例えば、マンガン系、コバルト系、ニッケル系のリチウムイオン電池や、各種のニッケル水素電池など、あらゆる種類の電池に対して本願発明を適用することができる。
【０００９】
《発明の第１の実施の形態》
図１は第１の実施の形態の構成を示す。組電池１はｎ個のセル１１，１２，１３，・・，１ｎが直列に接続されている。この組電池１の各セル１１〜１ｎの両端Ｃ０−Ｃ１、Ｃ１−Ｃ２、Ｃ２−Ｃ３、Ｃｎ−１−Ｃｎには、後述する電流バイパス回路２１〜２ｎ、過充電検出回路３１〜３ｎおよび過放電検出回路４１〜４ｎがそれぞれ並列に接続される。
【００１０】
図２は、電流バイパス回路、過充電検出回路および過放電検出回路の詳細を示す。なお、これらの回路は各セル１１〜１ｎに対してすべて共通である。電流バイパス回路２１〜２ｎは、抵抗器Ｒ１１とトランジスター（ＦＥＴ）Ｑ１が直列に接続された電流バイパス回路と、コンパレーターＣ１、インバーターＩＮＶ１および抵抗器Ｒ１２，Ｒ１３からなる制御回路とを備えている。コンパレーターＣ１は、制御電源電圧Ｖｃｃを抵抗器Ｒ１２とＲ１３で分圧したしきい値電圧Ｖｃ３とセル電圧とを比較する。
【数１】
Ｖｃ３＝Ｒ１３／（Ｒ１２＋Ｒ１３）・Ｖｃｃ
セル電圧がしきい値Ｖｃ３を超えるとコンパレーターＣ１の出力がローレベルになり、インバーターＩＮＶ１でハイレベルに反転される。それにより、トランジスターＱ１がオンし、それまでセルに流れていた充電電流が抵抗器Ｒ１１とトランジスターＱ１のバイパス回路を流れるようになり、セルの充電が緩和される。
【００１１】
過充電検出回路３１〜３ｎは、コンパレーターＣ２、インバーターＩＮＶ２および抵抗器Ｒ２５，Ｒ２６から構成される。コンパレーターＣ２は、制御電源電圧Ｖｃｃを抵抗器Ｒ２５とＲ２６で分圧したしきい値電圧Ｖｃ２とセル電圧とを比較する。
【数２】
Ｖｃ２＝Ｒ２６／（Ｒ２５＋Ｒ２６）・Ｖｃｃ
セル電圧がしきい値Ｖｃ２を超えるとコンパレーターＣ２の出力がローレベルになり、インバーターＩＮＶ２でハイレベルに反転されて過充電検知信号として出力される。
【００１２】
過放電検出回路４１〜４ｎは、コンパレーターＣ３と抵抗器Ｒ３５，Ｒ３６から構成される。コンパレーターＣ３は、制御電源電圧Ｖｃｃを抵抗器Ｒ３５とＲ３６で分圧したしきい値電圧Ｖｃ１とセル電圧とを比較する。
【数３】
Ｖｃ１＝Ｒ３６／（Ｒ３５＋Ｒ３６）・Ｖｃｃ
セル電圧がしきい値Ｖｃ１より低くなるとコンパレーターＣ３の出力がハイレベルになり、過放電検知信号として出力される。
【００１３】
ふたたび図１に戻って説明を続ける。過充電検出回路３１〜３ｎの出力はＯＲ素子５に接続されており、過充電検出回路３１〜３ｎのいずれかでセルの過充電状態が検知されると、ハイレベルの過充電検知信号がＯＲ素子５から充放電制御回路７へ送られる。また、過放電検出回路４１〜４ｎの出力はＯＲ素子６に接続されており、過放電検出回路４１〜４ｎのいずれかでセルの過放電状態が検知されると、ハイレベルの過放電検知信号がＯＲ素子６から充放電制御回路７へ送られる。
【００１４】
充放電制御回路７は、ＣＰＵとＲＯＭ、ＲＡＭ、Ａ／Ｄコンバーターなどの周辺部品から構成され、後述する制御プログラムを実行して組電池１の充放電を制御するとともに、過放電と過充電を監視する。
【００１５】
電圧センサー８は組電池１の両端電圧（以下、総電圧と呼ぶ）Ｖｔを検出し、検出した総電圧Ｖｔを充放電制御回路７へ出力する。充放電制御回路７は、組電池１の総電圧Ｖｔに対する充電状態ＳＯＣを計測し、ＳＯＣデータマップとして記憶しておき、計測した総電圧Ｖｔに対応する組電池１の充電状態ＳＯＣを表引き演算する。
【００１６】
なお、この一実施の形態では電圧センサー８により組電池１の総電圧Ｖｔを検出し、充放電制御回路７により総電圧Ｖｔに基づいて組電池１の充電状態ＳＯＣを求める例を示すが、電圧センサー８の代わりにＳＯＣ検出装置を設け、ＳＯＣ検出装置で検出した組電池１のＳＯＣを充放電制御回路７へ出力するようにしてもよい。
【００１７】
図３は、セルと組電池の充電状態ＳＯＣの過放電しきい値と過充電しきい値を示す。この一実施の形態では、セル１１〜１ｎと組電池１に対して、図３に示すように充電状態ＳＯＣの過放電しきい値と過充電しきい値を設定する。ここで、過放電しきい値とは、組電池１およびセル１１〜１ｎの破損を防止するために放電を停止すべきＳＯＣである。また、過充電しきい値とは、組電池１およびセル１１〜１ｎの破損を防止するために充電を停止すべきＳＯＣである。セル１１〜１ｎに対しては、過放電しきい値ＳＯＣｃ１［％］と過充電しきい値ＳＯＣｃ２［％］を設定する。また、組電池１に対しては、過放電しきい値ＳＯＣｔ１［％］と過充電しきい値ＳＯＣｔ２［％］を設定する。なお、ＳＯＣｃ１＜ＳＯＣｔ１、ＳＯＣｃ２＞ＳＯＣｔ２とするのが望ましい。
【００１８】
組電池の通常の使用状態において、セル電圧はセルの充電量、すなわち充電状態ＳＯＣと、また、組電池の総電圧は組電池の充電量、すなわち充電状態ＳＯＣとそれぞれ強い相関がある。この一実施の形態では、セル１１〜１ｎと組電池１の過充放電を監視するのにセル電圧と総電圧を用いる。
【００１９】
セル１１〜１ｎの過放電しきい値ＳＯＣｃ１に対応するセル電圧Ｖｃ１と、過充電しきい値ＳＯＣｃ２に対応するセル電圧Ｖｃ２とを計測し、過放電しきい値のセル電圧Ｖｃ１により過放電検出回路４１〜４ｎの抵抗器Ｒ３５、Ｒ３６の抵抗値を決定するとともに、過充電しきい値のセル電圧Ｖｃ２により過充電検出回路３１〜３ｎの抵抗器Ｒ２５、Ｒ２６の抵抗値を決定する。
【００２０】
また、組電池１の過放電しきい値ＳＯＣｔ１に対応する総電圧Ｖｔ１と、過充電しきい値ＳＯＣｔ２に対応する総電圧Ｖｔ２とを計測し、充放電制御回路７に記憶しておく。
【００２１】
図４は、図１に示す組電池１とその過充放電監視装置を搭載したパラレルハイブリッド車両の構成を示す。なお、本発明に係わる組電池の過充放電監視装置はパラレルハイブリッド車両に限定されず、例えばシリーズハイブリッド車両や電気自動車などの組電池を用いたあらゆる装置に適用することができる。
【００２２】
一実施の形態のパラレルハイブリッド車両はエンジン１０１の出力軸に交流モーター１０２の回転軸が直結されており、エンジン１０１とモーター１０２のいずれか一方または両方の制駆動力により走行する。エンジン１０１および／またはモーター１０２の制駆動力は変速機１０３および減速機１０４を介して駆動輪１０５ａ、１０５ｂへ伝達される。
【００２３】
組電池１は、インバーター１０６を介してモーター１０２へ駆動電力を供給するとともに、インバーター１０６を介してモーター１０２から回生電力を受け入れる。車両コントローラー１０７はエンジン１０１、インバーター１０６を制御する。開閉器１０８は、組電池１とインバーター１０６との間の遮断と接続を行う。
【００２４】
図５は、充放電制御回路７で実行される過充放電監視プログラムを示すフローチャートである。このフローチャートにより、第１の実施の形態の動作を説明する。ステップ１において、組電池１の中のいずれかのセルで過放電状態が検知されたか否かを確認し、いずれかのセルの過放電検知があればステップ２へ進み、過放電検知がなければステップ５へ進む。
【００２５】
いずれかのセルにおいて過放電状態が検知された場合は、ステップ２で放電禁止信号を車両コントローラー７へ出力する。車両コントローラー７は、この放電禁止信号を受信すると、インバーター１０６を制御して組電池１からモーター１０２への放電を停止する。
【００２６】
ステップ３で、組電池１の総電圧Ｖｔが過放電しきい値Ｖｔ１より大きいか否かを判定する。いずれかのセルの過放電状態が検知されたときに、組電池総電圧Ｖｔが過放電しきい値Ｖｔ１以下であれば、過放電状態が検知されたセル以外のすべてのセルも均等に過放電に近い状態にあり、組電池１の故障または異常ではない。したがって、この場合は放電のみを禁止してステップ１へ戻り、上述した処理を繰り返す。これにより、組電池１が過放電に近い状態にあるときにいずれかのセルで過放電状態が検知されたからといって、組電池１の故障または異常と判定して車両の走行を禁止してしまうような事態を避けることができる。
【００２７】
一方、いずれかのセルの過放電状態が検知されたときに、組電池総電圧Ｖｔが過放電しきい値Ｖｔ１より大きい場合は、過放電状態が検知されたセル以外のセルは正常な状態にあって、過放電状態が検知されたセルのみが突出して過放電状態にあるから、組電池１の故障または異常である。したがって、この場合はステップ４へ進み、車両コントローラー１０７へ異常信号を出力する。車両コントローラー１０７は、組電池１の異常信号を受信すると、開閉器１０８を開路して組電池１とインバーター１０６とを遮断する。これにより、故障または異常が発生している組電池１を使用し続けて故障または異常をさらに助長させ、車両の走行が困難な事態に至るのを避けることができる。
【００２８】
ステップ１においてセルの過放電検知がない場合はステップ５へ進み、組電池１のいずれかのセルで過充電状態が検知されたか否かを確認し、いずれかのセルの過充電検知があればステップ６へ進み、過充電検知がなければステップ９へ進む。
【００２９】
いずれかのセルで過充電状態が検知された場合は、ステップ６で充電禁止信号を車両コントローラー１０７へ出力する。車両コントローラー１０７は、この充電禁止信号を受信すると、インバーター１０６を制御してモーター１０２から組電池１への充電を停止する。
【００３０】
ステップ７で、組電池総電圧Ｖｔが過充電しきい値Ｖｔ２より小さいか否かを判定する。いずれかのセルの過充電状態が検知されたときに、組電池総電圧Ｖｔが過充電しきい値Ｖｔ２以上であれば、過充電状態が検知されたセル以外のすべてのセルも均等に過充電に近い状態にあり、組電池１の故障または異常ではない。したがって、この場合は充電のみを禁止してステップ１へ戻り、上述した処理を繰り返す。これにより、組電池１が過充電に近い状態にあるときにいずれかのセルで過充電状態が検知されたからといって、組電池１の故障または異常と判定して車両の走行を禁止してしまうような事態を避けることができる。
【００３１】
一方、いずれかのセルの過充電状態が検知されたときに、組電池総電圧Ｖｔが過充電しきい値Ｖｔ２より小さい場合は、過充電状態が検知されたセル以外のセルは正常な状態にあって、過充電状態が検知されたセルのみが突出して過充電状態にあるから、組電池１の故障または異常である。したがって、この場合はステップ８へ進み、車両コントローラー１０７へ異常信号を出力する。車両コントローラー１０７は、組電池１の異常信号を受信すると、開閉器１０８を開路して組電池１とインバーター１０６とを遮断する。これにより、故障または異常が発生している組電池１を使用し続けて故障または異常をさらに助長させ、車両の走行が困難な事態に至るのを避けることができる。
【００３２】
すべてのセル１１〜１ｎで過放電状態と過充電状態が検知されなかった場合は、ステップ９で、組電池総電圧Ｖｔが過放電しきい値Ｖｔ１より小さいか否かを判定する。組電池総電圧Ｖｔが過放電しきい値Ｖｔ１より小さいときはステップ１０へ進み、車両コントローラー１０７へ放電制限信号を出力する。車両コントローラー１０７は、この放電制限信号を受信すると、インバーター１０６を制御して組電池１からモーター１０２への放電量を制限する。これにより、組電池１が過放電状態になるのを未然に防ぐことができる。
【００３３】
また、組電池総電圧Ｖｔが過放電しきい値Ｖｔ１以上の場合はステップ１１へ進み、組電池総電圧Ｖｔが過充電しきい値Ｖｔ２より大きいか否かを判定する。組電池総電圧Ｖｔが過充電しきい値Ｖｔ２より大きいときはステップ１２へ進み、車両コントローラー１０７へ充電制限信号を出力する。車両コントローラー１０７は、この充電制限信号を受信すると、インバーター１０６を制御してモーター１０２から組電池１への充電量を制限する。これにより、組電池１が過充電状態になるのを未然に防ぐことができる。
【００３４】
なお、組電池総電圧Ｖｔが過放電しきい値Ｖｔ１以上でかつ過充電しきい値Ｖｔ２以下の範囲にあるときは、組電池１もセル１１〜１ｎも正常な状態にあり、ステップ１へ戻って上述した処理を繰り返す。
【００３５】
このように、第１の実施の形態によれば、組電池を構成するいずれかのセルの過放電状態が検出されたときに、組電池の過放電状態が検出された場合は、組電池異常信号を出力せず、放電禁止信号を出力するようにしたので、組電池が過放電に近い状態にあるときにいずれかのセルで過放電状態が検知されたからといって、組電池の故障または異常と判定して車両の走行を禁止してしまうような事態を避けることができる。また、組電池を構成するいずれかのセルの過放電状態が検出されたときに、組電池の過放電状態が検出されていない場合は、組電池異常信号を出力するようにしたので、故障または異常が発生している組電池を使用し続けて故障または異常をさらに助長させ、車両の走行が困難な事態に至るのを避けることができる。
【００３６】
また、第１の実施の形態によれば、組電池を構成するいずれかのセルの過充電状態が検出されたときに、組電池の過充電状態が検出された場合は、組電池異常信号を出力せず、充電禁止信号を出力するようにしたので、組電池が過充電に近い状態にあるときにいずれかのセルで過充電状態が検知されたからといって、組電池の故障または異常と判定して車両の走行を禁止してしまうような事態を避けることができる。また、組電池を構成するいずれかのセルの過充電状態が検出されたときに、組電池の過充電状態が検出されていない場合は、組電池異常信号を出力するようにしたので、故障または異常が発生している組電池を使用し続けて故障または異常をさらに助長させ、車両の走行が困難な事態に至るのを避けることができる。
【００３７】
このように第１の実施の形態によれば、監視内容の充実を図ることができ、車両システムとして最適な対応をとることができる。
【００３８】
《発明の第２の実施の形態》
上述した第１の実施の形態では、組電池１のいずれかのセルが過放電状態になったか、または過充電状態になったかを区別できる例を示した。セルが過放電状態にあるかまたは過充電状態あるかを区別して検出しない第２の実施の形態を説明する。
【００３９】
図６は第２の実施の形態の構成を示す。なお、図１に示す機器と同様な機器に対しては同一の符号を付して相違点を中心に説明する。この第２の実施の形態では、セルごとの過充電検出回路出力と過放電検出回路出力とが、セルごとに設けられるＯＲ素子へ接続される。例えばセル１１では、過充電検出回路３１の出力と過放電検出回路４１の出力とがともにＯＲ素子５１へ接続される。同様に、セル１ｎでは、過充電検出回路３ｎの出力と過放電検出回路４ｎの出力とがともにＯＲ素子５ｎへ接続される。これらのＯＲ素子５１〜５ｎの出力はＯＲ素子６へ接続され、ＯＲ素子６の出力は充放電制御回路７へ接続される。したがって、この第２の実施の形態では、組電池１の中のいずれかのセルが過充放電状態になったことのみを検知し、過充放電状態にあるセルを特定することはもちろん、過充電状態にあるのか過放電状態にあるのかの区別もしない。
【００４０】
この第２の実施の形態の電流バイパス回路２１〜２ｎ、過充電検出回路３１〜３ｎおよび過放電検出回路４１〜４ｎは、図２に示す第１の実施の形態の回路と同様である。また、第２の実施の形態のセル１１〜１ｎの過放電しきい値ＳＯＣｃ１、Ｖｃ１、過充電しきい値ＳＯＣｃ２、Ｖｃ２、組電池１の過放電しきい値ＳＯＣｔ１、Ｖｔ１、過充電しきい値ＳＯＣｔ２、Ｖｔ２については、図３に示す第１の実施の形態のしきい値と同様とする。さらに、第２の実施の形態の組電池１とその過充放電監視装置を搭載したパラレルハイブリッド車両の構成についても、図４に示す第１の実施の形態の構成と同様とする。
【００４１】
図７は、充放電制御回路７で実行される過充放電制御プログラムを示すフローチャートである。このフローチャートにより、第２の実施の形態の動作を説明する。ステップ２１において、組電池１の中のいずれかのセルで過充電状態と過放電状態のいずれかが検知されたか否かを確認し、いずれかのセルの過充放電検知があればステップ２２へ進み、過充放電検知がなければステップ２５へ進む。
【００４２】
いずれかのセルにおいて過充電状態と過放電状態のいずれかが検知された場合は、ステップ２２で充放電禁止信号を車両コントローラー１０７へ出力する。車両コントローラー１０７は、この過充放電禁止信号を受信すると、インバーター１０６を制御して組電池１からモーター１０２への放電と、モーター１０２から組電池１への充電を停止する。
【００４３】
ステップ２３で、組電池１の総電圧Ｖｔが過放電しきい値Ｖｔ１以上で、かつ過充電しきい値Ｖｔ２以下の状態にあるか否か、つまり組電池１が充放電可能な正常な状態にあるか否かを判定する。いずれかのセルで過充電状態と過放電状態のいずれかが検知されたときに、組電池総電圧Ｖｔが過放電しきい値Ｖｔ１以上でかつ過充電しきい値Ｖｔ２以下の範囲にあって、組電池１が充放電可能な正常な状態にあれば、過充放電状態が検知されたセル以外のセルが正常な状態にあって、過充放電状態が検知されたセルのみが突出して過放電または過充電状態にあるから、組電池１の故障または異常である。したがって、この場合はステップ２４へ進み、車両コントローラー１０７へ異常信号を出力する。車両コントローラー１０７は、組電池１の異常信号を受信すると、開閉器１０８を開路して組電池１とインバーター１０６とを遮断する。これにより、故障または異常が発生している組電池１を使用し続けて故障または異常をさらに助長させ、車両の走行が困難な事態に至るのを避けることができる。
【００４４】
一方、いずれかのセルで過充電状態と過放電状態のいずれかが検知されたときに、組電池総電圧Ｖｔが過放電しきい値Ｖｔ１以上でかつ過充電しきい値Ｖｔ２以下の範囲にない場合、つまり組電池１が充放電可能な正常な状態にない場合は、過充放電状態が検知されたセル以外のすべてのセルも均等に過充電または過放電に近い状態にあると考えられ、組電池１の故障または異常とは云えない。したがって、この場合は充放電を禁止してステップ２１へ戻り、上述した処理を繰り返す。これにより、組電池１が充放電可能な正常な状態にないときに、いずれかのセルで過充電または過放電状態が検知されたからといって、組電池１の故障または異常と判定して車両の走行を禁止してしまうような事態を避けることができる。
【００４５】
ステップ２１においてセルの過充放電検知がない場合はステップ２５へ進み、組電池総電圧Ｖｔが過放電しきい値Ｖｔ１より小さいか否かを判定する。組電池総電圧Ｖｔが過放電しきい値Ｖｔ１より小さいときはステップ２６へ進み、車両コントローラー１０７へ放電制限信号を出力する。車両コントローラー１０７は、この放電制限信号を受信すると、インバーター１０６を制御して組電池１からモーター１０２への放電量を制限する。これにより、組電池１が過放電状態になるのを未然に防ぐことができる。
【００４６】
また、組電池総電圧Ｖｔが過放電しきい値Ｖｔ１以上の場合はステップ２７へ進み、組電池総電圧Ｖｔが過充電しきい値Ｖｔ２より大きいか否かを判定する。組電池総電圧Ｖｔが過充電しきい値Ｖｔ２より大きいときはステップ２８へ進み、車両コントローラー１０７へ充電制限信号を出力する。車両コントローラー１０７は、この充電制限信号を受信すると、インバーター１０６を制御してモーター１０２から組電池１への充電量を制限する。これにより、組電池１が過充電状態になるのを未然に防ぐことができる。
【００４７】
組電池総電圧Ｖｔが過放電しきい値Ｖｔ１以上で、かつ過充電しきい値Ｖｔ２以下の範囲にあるときは、組電池１もセル１１〜１ｎも正常な状態にあり、ステップ２１へ戻って上述した処理を繰り返す。
【００４８】
このように、組電池を構成するいずれかのセルの過充電状態または過放電状態が検出されたときに、組電池の充放電可能な正常な状態が検出されない場合は、組電池異常信号を出力せず、充放電禁止信号を出力するようにしたので、組電池が充放電可能な正常な状態にないときに、いずれかのセルで過充電または過放電状態が検知されたからといって、組電池の故障または異常と判定して車両の走行を禁止してしまうような事態を避けることができる。また、組電池を構成するいずれかのセルの過充電状態または過放電状態が検出されたときに、組電池の充放電可能な正常な状態が検出された場合は、組電池異常信号を出力するようにしたので、故障または異常が発生している組電池を使用し続けて故障または異常をさらに助長させ、車両の走行が困難な事態に至るのを避けることができる。
【００４９】
このように第２の実施の形態によれば、監視内容の充実を図ることができ、システムとして最適な対応をとることができる。
【００５０】
特許請求の範囲の構成要素と一実施の形態の構成要素との対応関係は次の通りである。すなわち、電圧センサー８および充放電制御回路７が電池過放電検出手段、電池過充電検出手段および電池状態電検出手段を、過放電検出回路４１〜４ｎがセル過放電検出手段を、過充電検出回路３１〜３ｎがセル過充電検出手段を、過放電検出回路４１〜４ｎおよび過充電検出回路３１〜３ｎがセル過充放電検出手段をそれぞれ構成する。なお、本発明の特徴的な機能を損なわない限り、各構成要素は上記構成に限定されるものではない。
【図面の簡単な説明】
【図１】第１の実施の形態の組電池の過充放電監視装置の構成を示す図である。
【図２】電流バイパス回路、過充電検出回路および過放電検出回路の詳細回路図である。
【図３】セルと組電池の充電状態ＳＯＣの過放電しきい値と過充電しきい値を示す図である。
【図４】第１の実施の形態の組電池とその過充放電監視装置を搭載したパラレルハイブリッド車両の構成を示す図である。
【図５】第１の実施の形態の過充放電監視プログラムを示すフローチャートである。
【図６】第２の実施の形態の組電池の過充放電監視装置の構成を示す図である。
【図７】第２の実施の形態の過充放電監視プログラムを示すフローチャートである。
【符号の説明】
１　組電池
５、５１〜５ｎ、６　ＯＲ素子
７　充放電制御回路
８　電圧センサー
１１〜１ｎ　セル
２１〜２ｎ　電流バイパス回路
３１〜３ｎ　過充電検出回路
４１〜４ｎ　過放電検出回路
１０１　エンジン
１０２　モーター
１０３　変速機
１０４　減速機
１０５ａ、１０５ｂ　駆動輪
１０６　インバーター
１０７　車両コントローラー
１０８　開閉器[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an apparatus for monitoring an overcharge state and an overdischarge state of a battery pack.
[0002]
[Prior art]
2. Description of the Related Art In an assembled battery in which a plurality of unit cells (hereinafter, referred to as cells) are connected in series, a monitoring device that detects that any of the plurality of cells is in an overcharged state or an overdischarged state is known. (For example, see Patent Document 1).
[0003]
Prior art documents related to the invention of this application include the following.
[Patent Document 1]
Japanese Patent Application Laid-Open No. 05-258778
[Problems to be solved by the invention]
However, the conventional overcharge / discharge monitoring device for assembled batteries only detects the overcharge state or the overdischarge state of any of the cells, and the monitoring contents are poor and the system cannot be optimally handled. There's a problem.
[0005]
It is an object of the present invention to enhance the monitoring contents so that the system can be optimally handled.
[0006]
[Means for Solving the Problems]
The present invention does not output an assembled battery abnormality signal when an overdischarged state of the assembled battery is detected when an overdischarged state of any of the cells constituting the assembled battery or the cell parallel circuit is detected. Outputs a discharge prohibition signal. On the other hand, when an overdischarge state of any of the cells or the cell parallel circuit that constitutes the assembled battery is detected and an overdischarge state of the assembled battery is not detected, an assembled battery abnormality signal is output.
Further, according to the present invention, when an overcharged state of one of the cells constituting the battery pack or the cell parallel circuit is detected and the overcharged state of the battery pack is detected, an abnormal battery signal is output. Output a charge prohibition signal. On the other hand, when an overcharged state of any of the cells or the cell parallel circuit that constitutes the assembled battery is detected, and an overcharged state of the assembled battery is not detected, an abnormal battery signal is output.
Furthermore, the present invention, when the overcharge state or overdischarge state of any of the cells constituting the battery pack or the cell parallel circuit is detected, if the normal state of charge and discharge of the battery pack is not detected, Outputs the charge / discharge prohibition signal without outputting the battery pack abnormality signal. On the other hand, when an overcharge state or an overdischarge state of any of the cells or the cell parallel circuit constituting the assembled battery is detected, and a normal state in which the assembled battery can be charged and discharged is detected, the assembled battery is abnormal. Output a signal.
[0007]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the monitoring content can be enriched and an optimal response can be taken as a system.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment in which the present invention is applied to an assembled battery in which n cells (unit cells) are connected in series will be described. Note that the present invention is not limited to an assembled battery in which a plurality of cells are connected in series, but can also be applied to an assembled battery in which a plurality of cell parallel circuits in which a plurality of cells are connected in parallel are connected in series. . The invention of the present application is not particularly limited with respect to the type of battery, and for example, the present invention is applicable to all types of batteries such as manganese-based, cobalt-based, nickel-based lithium-ion batteries, and various nickel-metal hydride batteries. Can be applied.
[0009]
<< First Embodiment of the Invention >>
FIG. 1 shows the configuration of the first embodiment. The assembled battery 1 has n cells 11, 12, 13,..., 1n connected in series. Both ends C0-C1, C1-C2, C2-C3, and Cn-1-Cn of each of the cells 11-1n of the battery pack 1 are connected to a current bypass circuit 21-2n, an overcharge detection circuit 31-3n and an overcharge detection circuit 31-n described later. The discharge detection circuits 41 to 4n are respectively connected in parallel.
[0010]
FIG. 2 shows details of the current bypass circuit, the overcharge detection circuit, and the overdischarge detection circuit. These circuits are common to all the cells 11 to 1n. Each of the current bypass circuits 21 to 2n includes a current bypass circuit in which a resistor R11 and a transistor (FET) Q1 are connected in series, and a control circuit including a comparator C1, an inverter INV1, and resistors R12 and R13. The comparator C1 compares a cell voltage with a threshold voltage Vc3 obtained by dividing the control power supply voltage Vcc by resistors R12 and R13.
(Equation 1)
Vc3 = R13 / (R12 + R13) · Vcc
When the cell voltage exceeds the threshold value Vc3, the output of the comparator C1 becomes low level, and is inverted to high level by the inverter INV1. As a result, the transistor Q1 is turned on, and the charging current that has been flowing in the cell up to that point flows through the resistor R11 and the bypass circuit of the transistor Q1, so that the charging of the cell is eased.
[0011]
Each of the overcharge detection circuits 31 to 3n includes a comparator C2, an inverter INV2, and resistors R25 and R26. The comparator C2 compares the cell voltage with the threshold voltage Vc2 obtained by dividing the control power supply voltage Vcc by the resistors R25 and R26.
(Equation 2)
Vc2 = R26 / (R25 + R26) · Vcc
When the cell voltage exceeds the threshold value Vc2, the output of the comparator C2 becomes low level, is inverted to high level by the inverter INV2, and is output as an overcharge detection signal.
[0012]
Each of the overdischarge detection circuits 41 to 4n includes a comparator C3 and resistors R35 and R36. The comparator C3 compares the cell voltage with the threshold voltage Vc1 obtained by dividing the control power supply voltage Vcc by the resistors R35 and R36.
[Equation 3]
Vc1 = R36 / (R35 + R36) · Vcc
When the cell voltage becomes lower than the threshold value Vc1, the output of the comparator C3 becomes high level and is output as an overdischarge detection signal.
[0013]
Returning to FIG. 1, the description will be continued. The outputs of the overcharge detection circuits 31 to 3n are connected to the OR element 5, and when any of the overcharge detection circuits 31 to 3n detects the overcharge state of the cell, the high-level overcharge detection signal is ORed. It is sent from the element 5 to the charge / discharge control circuit 7. The outputs of the overdischarge detection circuits 41 to 4n are connected to an OR element 6, and when any of the overdischarge detection circuits 41 to 4n detects the overdischarge state of the cell, a high-level overdischarge detection signal is output. Is sent from the OR element 6 to the charge / discharge control circuit 7.
[0014]
The charge / discharge control circuit 7 includes a CPU and peripheral components such as a ROM, a RAM, and an A / D converter. The charge / discharge control circuit 7 controls a charge / discharge of the battery pack 1 by executing a control program described later, and performs overdischarge and overcharge. Monitor.
[0015]
The voltage sensor 8 detects a voltage (hereinafter, referred to as a total voltage) Vt across the assembled battery 1 and outputs the detected total voltage Vt to the charge / discharge control circuit 7. The charge / discharge control circuit 7 measures the state of charge SOC of the battery pack 1 with respect to the total voltage Vt, stores the SOC as a SOC data map, and calculates the state of charge SOC of the battery pack 1 corresponding to the measured total voltage Vt in a table. I do.
[0016]
In this embodiment, an example is shown in which the voltage sensor 8 detects the total voltage Vt of the battery pack 1 and the charge / discharge control circuit 7 determines the state of charge SOC of the battery pack 1 based on the total voltage Vt. An SOC detection device may be provided instead of the sensor 8, and the SOC of the battery pack 1 detected by the SOC detection device may be output to the charge / discharge control circuit 7.
[0017]
FIG. 3 shows an overdischarge threshold and an overcharge threshold of the state of charge SOC of the cell and the assembled battery. In this embodiment, an overdischarge threshold and an overcharge threshold of the state of charge SOC are set for the cells 11 to 1n and the battery pack 1 as shown in FIG. Here, the overdischarge threshold is the SOC at which the discharge should be stopped in order to prevent the battery pack 1 and the cells 11 to 1n from being damaged. The overcharge threshold is an SOC at which charging should be stopped in order to prevent damage to the assembled battery 1 and the cells 11 to 1n. An overdischarge threshold value SOCc1 [%] and an overcharge threshold value SOCc2 [%] are set for cells 11 to 1n. For battery pack 1, overdischarge threshold value SOCt1 [%] and overcharge threshold value SOCt2 [%] are set. It is desirable that SOCc1 <SOct1, SOCc2> SOct2.
[0018]
In a normal use state of the battery pack, the cell voltage has a strong correlation with the charge amount of the cell, that is, the state of charge SOC, and the total voltage of the battery pack has a strong correlation with the charge amount of the battery pack, that is, the charge state SOC. In this embodiment, the cell voltage and the total voltage are used to monitor the overcharge / discharge of the cells 11 to 1n and the battery pack 1.
[0019]
A cell voltage Vc1 corresponding to the overdischarge threshold value SOCc1 and a cell voltage Vc2 corresponding to the overcharge threshold value SOCc2 of the cells 11 to 1n are measured, and an overdischarge detection circuit is determined based on the cell voltage Vc1 of the overdischarge threshold value. The resistance values of the resistors R35 and R36 of 41 to 4n are determined, and the resistance values of the resistors R25 and R26 of the overcharge detection circuits 31 to 3n are determined based on the cell voltage Vc2 of the overcharge threshold.
[0020]
Further, a total voltage Vt1 corresponding to the overdischarge threshold value SOCt1 of the battery pack 1 and a total voltage Vt2 corresponding to the overcharge threshold value SOCt2 are measured and stored in the charge / discharge control circuit 7.
[0021]
FIG. 4 shows a configuration of a parallel hybrid vehicle equipped with the battery pack 1 shown in FIG. 1 and its overcharge / discharge monitoring device. The overcharge / discharge monitoring device for a battery pack according to the present invention is not limited to a parallel hybrid vehicle, and may be applied to any device using a battery pack, such as a series hybrid vehicle or an electric vehicle.
[0022]
In the parallel hybrid vehicle according to one embodiment, a rotating shaft of an AC motor 102 is directly connected to an output shaft of an engine 101, and the vehicle runs with the braking / driving force of one or both of the engine 101 and the motor 102. The braking / driving force of the engine 101 and / or the motor 102 is transmitted to the drive wheels 105a and 105b via the transmission 103 and the speed reducer 104.
[0023]
The battery pack 1 supplies drive power to the motor 102 via the inverter 106 and receives regenerative power from the motor 102 via the inverter 106. The vehicle controller 107 controls the engine 101 and the inverter 106. The switch 108 disconnects and connects the battery pack 1 and the inverter 106.
[0024]
FIG. 5 is a flowchart showing an overcharge / discharge monitoring program executed by the charge / discharge control circuit 7. The operation of the first embodiment will be described with reference to this flowchart. In step 1, it is checked whether an overdischarge state is detected in any of the cells in the battery pack 1. If overdischarge is detected in any of the cells, the process proceeds to step 2, and if no overdischarge is detected, Proceed to step 5.
[0025]
If an overdischarge state is detected in any of the cells, a discharge prohibition signal is output to the vehicle controller 7 in step 2. When receiving the discharge prohibition signal, the vehicle controller 7 controls the inverter 106 to stop discharging from the battery pack 1 to the motor 102.
[0026]
In step 3, it is determined whether or not the total voltage Vt of the battery pack 1 is larger than the overdischarge threshold value Vt1. If the total battery voltage Vt is equal to or lower than the overdischarge threshold value Vt1 when the overdischarge state of any of the cells is detected, all cells other than the cell in which the overdischarge state is detected are uniformly overdischarged. And it is not a failure or abnormality of the battery pack 1. Therefore, in this case, only the discharge is prohibited, the process returns to step 1, and the above-described process is repeated. Thus, when the overdischarge state is detected in any of the cells when the battery pack 1 is in a state close to overdischarge, it is determined that the battery pack 1 is malfunctioning or abnormal, and the vehicle is prohibited from running. It is possible to avoid such a situation.
[0027]
On the other hand, when the overdischarge state of any of the cells is detected and the assembled battery total voltage Vt is larger than the overdischarge threshold Vt1, the cells other than the cell in which the overdischarge state is detected are in a normal state. Since only the cells in which the overdischarge state is detected are protruding and in the overdischarge state, the battery pack 1 is malfunctioning or abnormal. Therefore, in this case, the process proceeds to step 4 and outputs an abnormal signal to the vehicle controller 107. When receiving the abnormal signal of the battery pack 1, the vehicle controller 107 opens the switch 108 to cut off the battery pack 1 and the inverter 106. As a result, it is possible to continue using the battery pack 1 in which the failure or abnormality has occurred, to further promote the failure or abnormality, and to avoid a situation in which running of the vehicle is difficult.
[0028]
If there is no overdischarge detection in step 1, the process proceeds to step 5, and it is checked whether an overcharge state has been detected in any of the cells of the battery pack 1. Proceed to step 6 and proceed to step 9 if there is no overcharge detection.
[0029]
If an overcharge state is detected in any of the cells, a charge prohibition signal is output to the vehicle controller 107 in step 6. Upon receiving the charging prohibition signal, the vehicle controller 107 controls the inverter 106 to stop charging the assembled battery 1 from the motor 102.
[0030]
In step 7, it is determined whether or not the assembled battery total voltage Vt is smaller than the overcharge threshold value Vt2. When the overcharge state of any of the cells is detected, if the total battery voltage Vt is equal to or higher than the overcharge threshold value Vt2, all cells other than the cell in which the overcharge state is detected are equally overcharged. And it is not a failure or abnormality of the battery pack 1. Therefore, in this case, only charging is prohibited and the process returns to step 1 to repeat the above-described processing. Thus, when the overcharge state is detected in any of the cells when the battery pack 1 is close to overcharge, it is determined that the battery pack 1 is malfunctioning or abnormal, and the vehicle is prohibited from running. It is possible to avoid such a situation.
[0031]
On the other hand, when the overcharged state of any one of the cells is detected and the assembled battery total voltage Vt is smaller than the overcharge threshold Vt2, the cells other than the cell in which the overcharged state is detected are in a normal state. Since only the cell in which the overcharged state is detected is protruded and is in the overcharged state, the battery pack 1 is malfunctioning or abnormal. Therefore, in this case, the process proceeds to step 8 and outputs an abnormal signal to the vehicle controller 107. When receiving the abnormal signal of the battery pack 1, the vehicle controller 107 opens the switch 108 to cut off the battery pack 1 and the inverter 106. As a result, it is possible to continue using the battery pack 1 in which the failure or abnormality has occurred, to further promote the failure or abnormality, and to avoid a situation in which running of the vehicle is difficult.
[0032]
When the overdischarge state and the overcharge state are not detected in all the cells 11 to 1n, it is determined in a step 9 whether or not the assembled battery total voltage Vt is smaller than the overdischarge threshold value Vt1. When the assembled battery total voltage Vt is smaller than the overdischarge threshold value Vt1, the process proceeds to step 10, and outputs a discharge limit signal to the vehicle controller 107. Upon receiving this discharge limiting signal, vehicle controller 107 controls inverter 106 to limit the amount of discharge from battery pack 1 to motor 102. Thereby, it is possible to prevent the battery pack 1 from being over-discharged.
[0033]
If the battery pack total voltage Vt is equal to or higher than the overdischarge threshold value Vt1, the process proceeds to step 11, and it is determined whether the battery pack total voltage Vt is greater than the overcharge threshold value Vt2. When the battery pack total voltage Vt is larger than the overcharge threshold value Vt2, the process proceeds to step 12, and outputs a charge limit signal to the vehicle controller 107. When receiving the charge restriction signal, the vehicle controller 107 controls the inverter 106 to restrict the amount of charge from the motor 102 to the battery pack 1. This can prevent the battery pack 1 from being overcharged.
[0034]
When the total battery voltage Vt is in the range of not less than the overdischarge threshold value Vt1 and not more than the overcharge threshold value Vt2, both the assembled battery 1 and the cells 11 to 1n are in a normal state, and the process returns to step 1. The above-described processing is repeated.
[0035]
As described above, according to the first embodiment, when the overdischarge state of any of the cells constituting the assembled battery is detected, and the overdischarge state of the assembled battery is detected, Since a signal is not output and a discharge prohibition signal is output, even if an overdischarge state is detected in any of the cells when the battery pack is nearly overdischarged, failure of the battery pack or failure of the battery pack It is possible to avoid a situation in which the vehicle is determined to be abnormal and running of the vehicle is prohibited. In addition, when an overdischarge state of any of the cells constituting the assembled battery is detected and the overdischarge state of the assembled battery is not detected, an abnormal battery signal is output. The failure or abnormality can be further promoted by continuing to use the battery pack in which the abnormality has occurred, and it is possible to avoid a situation in which running of the vehicle is difficult.
[0036]
Further, according to the first embodiment, when an overcharged state of any of the cells constituting the assembled battery is detected and the overcharged state of the assembled battery is detected, the battery pack abnormality signal is output. Since the battery is not output and a charge prohibition signal is output, if the overcharge state is detected in one of the cells when the battery pack is nearly overcharged, the battery pack may fail or fail. It is possible to avoid a situation in which the determination is made and the running of the vehicle is prohibited. In addition, when an overcharged state of any of the cells constituting the assembled battery is detected and the overcharged state of the assembled battery is not detected, an abnormal battery signal is output. The failure or abnormality can be further promoted by continuing to use the battery pack in which the abnormality has occurred, and it is possible to avoid a situation in which running of the vehicle is difficult.
[0037]
As described above, according to the first embodiment, the monitoring contents can be enhanced, and an optimal response can be taken as a vehicle system.
[0038]
<< Second Embodiment of the Invention >>
In the above-described first embodiment, an example has been described in which it is possible to distinguish whether any of the cells of the battery pack 1 is in the overdischarged state or the overcharged state. A second embodiment in which whether a cell is in an overdischarged state or an overcharged state is not detected separately will be described.
[0039]
FIG. 6 shows the configuration of the second embodiment. Note that the same reference numerals are given to the same devices as those shown in FIG. 1 and the description will focus on the differences. In the second embodiment, the output of the overcharge detection circuit and the output of the overdischarge detection circuit for each cell are connected to an OR element provided for each cell. For example, in the cell 11, both the output of the overcharge detection circuit 31 and the output of the overdischarge detection circuit 41 are connected to the OR element 51. Similarly, in the cell 1n, the output of the overcharge detection circuit 3n and the output of the overdischarge detection circuit 4n are both connected to the OR element 5n. Outputs of these OR elements 51 to 5n are connected to an OR element 6, and an output of the OR element 6 is connected to a charge / discharge control circuit 7. Therefore, in the second embodiment, it is detected that only one of the cells in the battery pack 1 is in the overcharged / discharged state, and the cell in the overcharged / discharged state is of course specified. Neither is it in charge or in overdischarge.
[0040]
The current bypass circuits 21 to 2n, the overcharge detection circuits 31 to 3n, and the overdischarge detection circuits 41 to 4n according to the second embodiment are the same as the circuits according to the first embodiment shown in FIG. Also, the overdischarge thresholds SOCc1 and Vc1, the overcharge thresholds SOCc2 and Vc2, the overdischarge thresholds SOCt1 and Vt1, the overcharge threshold of the battery pack 1 of the cells 11 to 1n of the second embodiment. SOCt2 and Vt2 are the same as the threshold values of the first embodiment shown in FIG. Further, the configuration of the parallel hybrid vehicle equipped with the battery pack 1 of the second embodiment and the overcharge / discharge monitoring device thereof is the same as the configuration of the first embodiment shown in FIG.
[0041]
FIG. 7 is a flowchart showing an overcharge / discharge control program executed by the charge / discharge control circuit 7. The operation of the second embodiment will be described with reference to this flowchart. In step 21, it is confirmed whether any of the overcharged state and the overdischarged state is detected in any of the cells in the assembled battery 1. If any of the cells is detected as overcharged or overdischarged, the process proceeds to step 22. The process proceeds to step 25 if there is no overcharge / discharge detection.
[0042]
If any of the overcharge state and the overdischarge state is detected in any of the cells, a charge / discharge prohibition signal is output to the vehicle controller 107 in step 22. Upon receiving this overcharge / discharge prohibition signal, the vehicle controller 107 controls the inverter 106 to stop discharging from the battery pack 1 to the motor 102 and stopping charging from the motor 102 to the battery pack 1.
[0043]
In step 23, it is determined whether or not the total voltage Vt of the battery pack 1 is equal to or higher than the overdischarge threshold value Vt1 and equal to or lower than the overcharge threshold value Vt2, that is, to a normal state in which the battery pack 1 can be charged and discharged. It is determined whether or not there is. When any of the overcharge state and the overdischarge state is detected in any of the cells, the battery pack total voltage Vt is in the range of not less than the overdischarge threshold Vt1 and not more than the overcharge threshold Vt2, If the battery pack 1 is in a normal state in which charging and discharging can be performed, cells other than the cell in which the overcharging / discharging state is detected are in a normal state, and only the cell in which the overcharging / discharging state is detected protrudes and overdischarges. Alternatively, since the battery is in the overcharged state, the battery pack 1 is out of order or is abnormal. Therefore, in this case, the process proceeds to step 24, where an abnormal signal is output to the vehicle controller 107. When receiving the abnormal signal of the battery pack 1, the vehicle controller 107 opens the switch 108 to cut off the battery pack 1 and the inverter 106. As a result, it is possible to continue using the battery pack 1 in which the failure or abnormality has occurred, to further promote the failure or abnormality, and to avoid a situation in which running of the vehicle is difficult.
[0044]
On the other hand, when any of the overcharge state and the overdischarge state is detected in any of the cells, the assembled battery total voltage Vt is not in the range of the overdischarge threshold Vt1 or more and the overcharge threshold Vt2 or less. In the case, that is, when the battery pack 1 is not in a normal state capable of charging / discharging, it is considered that all the cells other than the cell in which the overcharge / discharge state is detected are also in a state close to overcharge or overdischarge, It cannot be said that the battery pack 1 is malfunctioning or abnormal. Therefore, in this case, charging and discharging are prohibited, and the process returns to step 21 to repeat the above-described processing. Thereby, when the battery pack 1 is not in a normal state in which charging and discharging can be performed, it is determined that the battery pack 1 is malfunctioning or abnormal because the overcharge or overdischarge state is detected in any of the cells. It is possible to avoid a situation in which traveling of the vehicle is prohibited.
[0045]
If there is no overcharge / discharge detection of the cell in step 21, the process proceeds to step 25, and it is determined whether or not the assembled battery total voltage Vt is smaller than the overdischarge threshold Vt1. When the battery pack total voltage Vt is smaller than the overdischarge threshold value Vt1, the process proceeds to step 26, and a discharge limit signal is output to the vehicle controller 107. Upon receiving this discharge limiting signal, vehicle controller 107 controls inverter 106 to limit the amount of discharge from battery pack 1 to motor 102. Thereby, it is possible to prevent the battery pack 1 from being over-discharged.
[0046]
If the battery pack total voltage Vt is equal to or higher than the overdischarge threshold value Vt1, the process proceeds to step 27, and it is determined whether the battery pack total voltage Vt is greater than the overcharge threshold value Vt2. If the total battery voltage Vt is greater than the overcharge threshold value Vt2, the process proceeds to step 28, where a charge limit signal is output to the vehicle controller 107. When receiving the charge restriction signal, the vehicle controller 107 controls the inverter 106 to restrict the amount of charge from the motor 102 to the battery pack 1. This can prevent the battery pack 1 from being overcharged.
[0047]
When the assembled battery total voltage Vt is in the range of not less than the overdischarge threshold value Vt1 and not more than the overcharge threshold value Vt2, both the assembled battery 1 and the cells 11 to 1n are in a normal state, and the process returns to step 21. The above processing is repeated.
[0048]
As described above, when an overcharged state or an overdischarged state of any of the cells constituting the assembled battery is detected, and a normal state in which the assembled battery can be charged and discharged is not detected, the assembled battery abnormality signal is output. Instead, a charge / discharge prohibition signal is output, and when the battery pack is not in a normal state capable of charging / discharging, an overcharge or overdischarge state is detected in any of the cells. It is possible to avoid a situation in which the running of the vehicle is prohibited by determining that the battery is faulty or abnormal. In addition, when an overcharge state or an overdischarge state of any of the cells constituting the assembled battery is detected, and a normal state in which the assembled battery can be charged and discharged is detected, an abnormal battery signal is output. With this configuration, it is possible to further use the assembled battery in which a failure or abnormality has occurred, to further promote the failure or abnormality, and to avoid a situation in which the vehicle is difficult to travel.
[0049]
As described above, according to the second embodiment, the monitoring contents can be enhanced, and the system can be optimally handled.
[0050]
The correspondence between the components of the claims and the components of the embodiment is as follows. That is, the voltage sensor 8 and the charge / discharge control circuit 7 correspond to the battery overdischarge detecting means, the battery overcharge detecting means and the battery state charge detecting means, the overdischarge detecting circuits 41 to 4n correspond to the cell overdischarge detecting means, and the overcharge detecting circuit 31 to 3n constitute cell overcharge detection means, and overdischarge detection circuits 41 to 4n and overcharge detection circuits 31 to 3n constitute cell overcharge / discharge detection means, respectively. Note that each component is not limited to the above configuration as long as the characteristic functions of the present invention are not impaired.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a battery pack overcharge / discharge monitoring apparatus according to a first embodiment.
FIG. 2 is a detailed circuit diagram of a current bypass circuit, an overcharge detection circuit, and an overdischarge detection circuit.
FIG. 3 is a diagram showing an overdischarge threshold and an overcharge threshold of a state of charge SOC of a cell and a battery pack;
FIG. 4 is a diagram illustrating a configuration of a parallel hybrid vehicle equipped with the assembled battery and the overcharge / discharge monitoring device thereof according to the first embodiment.
FIG. 5 is a flowchart illustrating an overcharge / discharge monitoring program according to the first embodiment;
FIG. 6 is a diagram illustrating a configuration of a battery pack overcharge / discharge monitoring apparatus according to a second embodiment.
FIG. 7 is a flowchart illustrating an overcharge / discharge monitoring program according to a second embodiment;
[Explanation of symbols]
Reference Signs List 1 battery pack 5, 51 to 5n, 6 OR element 7 charge / discharge control circuit 8 voltage sensor 11 to 1n cell 21 to 2n current bypass circuit 31 to 3n overcharge detection circuit 41 to 4n overdischarge detection circuit 101 engine 102 motor 103 speed change Machine 104 Reduction gear 105a, 105b Drive wheel 106 Inverter 107 Vehicle controller 108 Switch

Claims

An apparatus for monitoring an overdischarge state of an assembled battery in which a plurality of unit cells (hereinafter, referred to as cells) are connected in series, or an assembled battery in which a plurality of cell parallel circuits in which a plurality of cells are connected in parallel are connected in series. ,
Battery over-discharge detection means for detecting an over-discharge state of the battery pack,
Cell overdischarge detection means for detecting an overdischarge state of any of the cells or the cell parallel circuit constituting the battery pack,
When an overdischarge state of any of the cells or the cell parallel circuit that constitutes the battery pack is detected, and an overdischarge state of the battery pack is detected, no battery pack abnormality signal is output, An overdischarge monitoring device for a battery pack, which outputs a discharge prohibition signal.

The apparatus for monitoring overdischarge of a battery pack according to claim 1,
When an overdischarge state of any of the cells or the cell parallel circuit that constitutes the assembled battery is detected, and an overdischarge state of the assembled battery is not detected, an abnormal battery signal is output. A device for monitoring overdischarge of a battery pack.

The over-discharge monitoring device for a battery pack according to claim 1 or 2,
When an overdischarge state of the battery pack is detected when an overdischarge state of the cell or the cell parallel circuit is not detected, a discharge limit signal is output, and overdischarge monitoring of the battery pack is performed. apparatus.

An apparatus for monitoring an overcharged state of an assembled battery in which a plurality of unit cells (hereinafter, referred to as cells) are connected in series, or an assembled battery in which a plurality of cell parallel circuits in which a plurality of cells are connected in parallel are connected in series. ,
Battery overcharge detection means for detecting an overcharged state of the battery pack,
Cell overcharge detection means for detecting an overcharged state of any of the cells or the cell parallel circuit constituting the battery pack,
When an overcharged state of any of the cells or the cell parallel circuit that constitutes the assembled battery is detected, and an overcharged state of the assembled battery is detected, the assembled battery abnormality signal is not output, An overcharge monitoring device for a battery pack, which outputs a charge prohibition signal.

The apparatus for monitoring overcharge of a battery pack according to claim 4,
When an overcharged state of any of the cells or the cell parallel circuit constituting the assembled battery is detected, if the overcharged state of the assembled battery is not detected, an abnormal battery signal is output. A battery pack overcharge monitoring device characterized by the above-mentioned.

The overcharge monitoring device for an assembled battery according to claim 4 or 5,
When the overcharge state of the battery pack is detected when the overcharge state of the cell or the cell parallel circuit is not detected, a charge limit signal is output, and the overcharge monitoring of the battery pack is performed. apparatus.

The overcharge state and the overdischarge state of an assembled battery in which a plurality of unit cells (hereinafter, referred to as cells) are connected in series or an assembled battery in which a plurality of cell parallel circuits in which a plurality of cells are connected in parallel are connected in series are monitored. A device,
A battery state detection means for detecting a normal state in which the battery pack can be charged and discharged,
Cell overcharge / discharge detection means for detecting an overcharge state and an overdischarge state of any of the cells or the cell parallel circuit constituting the battery pack,
When an overcharged state or an overdischarged state of any of the cells or the cell parallel circuit constituting the assembled battery is detected, if a normal state in which the assembled battery can be charged and discharged is not detected, the assembled battery is An overcharge / discharge monitoring device for an assembled battery, which outputs a charge / discharge prohibition signal without outputting an abnormal signal.

The apparatus for monitoring overcharge / discharge of a battery pack according to claim 7,
When an overcharged state or an overdischarged state of any of the cells or the cell parallel circuit constituting the assembled battery is detected, a normal state in which the assembled battery can be charged and discharged is detected. An overcharge / discharge monitoring device for an assembled battery, which outputs a battery abnormality signal.

An overcharge / discharge monitoring device for an assembled battery according to claim 7 or 8,
The battery state detection means detects an overcharge state and an overdischarge state of the battery pack,
When the overcharge state and the overdischarge state of the cell or the cell parallel circuit are not detected, and when the overcharge state of the battery pack is detected, a charge limit signal is output, and the overdischarge state of the battery pack is output. An overcharge / discharge monitoring apparatus for an assembled battery, which outputs a discharge limit signal when a signal is detected.