JP2004191150A

JP2004191150A - Remaining capacity operating device and its method for secondary battery

Info

Publication number: JP2004191150A
Application number: JP2002358637A
Authority: JP
Inventors: Toshifumi Ueda; 利史植田; Yoshitada Nakao; 善忠中尾; Nobuyasu Morishita; 展安森下; Kazuhiro Okawa; 和宏大川
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 2002-12-10
Filing date: 2002-12-10
Publication date: 2004-07-08
Anticipated expiration: 2022-12-10
Also published as: JP4125105B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a remaining capacity operating device and its method capable of accurately estimating the remaining capacity of the secondary battery. <P>SOLUTION: This remaining capacity operating device for the secondary battery comprises a temperature measuring part for measuring a temperature, a remaining capacity estimating part for estimating the remaining capacity of the secondary battery on the basis of the self-discharge electric capacity derived on the basis of a table or a function applying the temperature in self-discharging and the elapsed time from the start of self-discharging to the present as parameters, and the capacity effectively reduced by memory effect generated by the repeating of charging and self-discharging, and an output part for outputting the information of the remaining capacity. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、二次電池の残存容量演算装置及びその残存容量演算方法に関する。
【０００２】
【従来の技術】
従来、電子・電気機器のバックアップ用電源には鉛蓄電池が多く用いられていたが、最近はニッケル−金属水素化物電池の需要が高まっている。ニッケル−金属水素化物電池は鉛蓄電池に比べて高エネルギー密度で、軽量・小型化が可能であることがその要因である。
【０００３】
ニッケル−金属水素化物電池は常時微少電流で充電（トリクル充電）すると耐久特性が低下するため、充電方法としては、間欠充電が採用されている。間欠充電は、強制放電あるいは放置による自己放電によって電池から取り出せる容量（以下、「残存容量」と言う。）が閾値を下回った時に補充電を行う方法である。例えば、特開２０００−１５００００号公報に従来例１のバックアップ電源の管理方法が開示されている。従来例１は、ニッケル−水素蓄電池の充電休止中の温度に基づいて、その充電休止中の自己放電電気量を算出し、自己放電電気量相当分を間欠充電するバックアップ電源の管理方法である。
【０００４】
ニッケル−金属水素化物電池には、充電・不完全放電を繰り返すとメモリ効果により容量が実効的に減少する性質がある。従って、ニッケル−金属水素化物電池を充放電を繰り返す装置に使用する場合には、その充放電制御において、メモリ効果をどのように考慮するかが問題となる。
【０００５】
特開平９−１２９２６７号公報に従来例２の蓄電池の状態管理装置が開示されている。従来例２は、電気自動車等の移動体の駆動用電源として用いられるニッケル・水素蓄電池（ニッケル−金属水素化物電池）の残存容量を計算する、蓄電池の状態管理装置である。蓄電池が充放電された回数に応じて、蓄電池の放電電圧、電池温度、放電電流より計算された残存容量を補正する。
【０００６】
特開２００１−１２６７７６号公報に従来例３の二次電池の容量表示方法が開示されている。従来例３は、メモリ効果の生じた二次電池をリフレッシュ放電した後、充電回数または放電回数をカウントし、カウント値が多くなると残存容量を少なく補正して表示する二次電池の容量表示方法である。補正量は、カウント値に比例した量である。
【０００７】
【特許文献１】
特開２０００−１５００００号公報
【特許文献２】
特開平９−１２９２６７号公報
【特許文献３】
特開２００１−１２６７７６号公報
【０００８】
【発明が解決しようとする課題】
バックアップ電池は通常使用されず、停電等の緊急時に使用される。ある残存容量を有すると推定していたバックアップ電池を停電時に使用したところ、その実際の残存容量が空であれば、バックアップ電池から電力供給を受けるべき装置を動かすことができず、大きなトラブルが発生する。そのため、電池の残存容量を常に正確に把握しなければならない。
【０００９】
本発明の発明者は、不完全放電と充電の繰り返し時のみならず、放置による自己放電と充電の繰り返しによっても、二次電池にメモリ効果が生じ、容量が実効的に減少することを見いだした。「放電」時には、二次電池から外部負荷に電流が供給されるが、「自己放電」時には供給されない。従来例２及び従来例３に記載されている方法は、放電と充電の繰り返しによって生じるメモリ効果を、二次電池の残存容量の計算時に考慮している。しかし、自己放電と充電の繰り返しによって生じるメモリ効果を、二次電池の残存容量の計算時に考慮していなかった。
【００１０】
従来例１に記載されているバックアップ電源の間欠充電は、放置による自己放電と補充電の繰り返しである。従来例１のバックアップ電源の管理方法は、充電休止中の自己放電電気量に対して温度補正のみを行い、メモリ効果による減少分を補正していなかった。従って、推定した残存容量と実際に使用できる容量とにズレがあった。
【００１１】
本発明は、上記従来の問題点を解決するもので、充電と自己放電の繰り返しによって生じるメモリ効果を考慮し、二次電池の残存容量を正確に推定する高精度の残存容量演算装置及びその残存容量演算方法を提供することを目的とする。
【００１２】
【課題を解決するための手段】
上記課題を解決するため、本発明は以下の構成を有する。
請求項１に記載の発明は、温度を測定する温度測定部と、自己放電時の温度と自己放電開始から現在までの経過時間とをパラメータとする表又は関数に基づいて導出した自己放電電気量と、充電と自己放電の繰り返しによって生じたメモリ効果によって実効的に減少する容量と、に基づいて二次電池の残存容量を推定する残存容量推定部と、前記残存容量の情報を出力する出力部と、を有することを特徴とする二次電池の残存容量演算装置である。
出力部が出力する残存容量の情報は任意である。残存容量の情報は、例えば残存容量を表す８ビットのデジタル値、残存容量に比例したアナログ電圧、又は残存容量が所定の閾値以下になった場合にロウレベルになり所定の閾値より大きければハイレベルになる１ビットのデジタル値であっても良い。残存容量の情報の出力は、例えば残存容量の情報を有する伝送信号を有線又は無線の通信回線を通じて伝送すること、その画像表示、その音声表示又は発光素子（例えばＬＥＤ（ＬｉｇｈｔＥｍｉｔｔｉｎｇＤｉｏｄｅ）によるその表示であっても良い。
【００１３】
請求項２に記載の発明は、前記温度測定部は、更に充電完了時点から次の充電開始時点までの自己放電期間毎の前記温度の平均値を算出し、完全放電後における各自己放電期間の前記平均値の中で最大の値である最大自己放電期間平均温度を抽出し、前記残存容量推定部は、更に前記最大自己放電期間平均温度をパラメータとする非線形変換の表又は関数に基づいて前記メモリ効果によって実効的に減少する容量を導出することを特徴とする請求項１に記載の二次電池の残存容量演算装置である。
【００１４】
請求項３に記載の発明は、前記二次電池が完全放電した後に、前記二次電池が自己放電状態から充電状態に変化した回数又は充電状態から自己放電状態に変化した回数をカウントするカウント部を更に有し、前記残存容量推定部は、更に前記回数をパラメータとする非線形変換の表又は関数に基づいて前記メモリ効果によって実効的に減少する容量を導出することを特徴とする請求項１又は請求項２に記載の二次電池の残存容量演算装置である。
【００１５】
請求項４に記載の発明は、前記二次電池が、１又は複数の二次電池セルを直列に接続した直列接続電池群を複数個並列接続した二次電池パックであり、前記温度測定部は、少なくとも２以上の前記直列接続電池群の温度を測定し、２以上の前記直列接続電池群の温度の平均値を算出する温度平均化部を更に有し、前記残存容量推定部は、前記温度平均化部が出力する平均値を温度の値として、前記自己放電電気量及び前記メモリ効果によって実効的に減少する容量の少なくともいずれか１つを導出する、ことを特徴とする請求項１〜請求項３のいずれかの請求項に記載の二次電池の残存容量演算装置である。
【００１６】
請求項５に記載の発明は、前記二次電池が、１又は複数の二次電池セルを直列に接続した直列接続電池群を複数個並列接続した二次電池パックであり、前記温度測定部は、少なくとも２以上の前記直列接続電池群の温度を測定し、前記残存容量推定部は、それぞれの前記直列接続電池群毎の残存容量を推定し、それぞれの前記直列接続電池群毎の残存容量に基づいて二次電池全体の前記残存容量を推定する、ことを特徴とする請求項１〜請求項３のいずれかの請求項に記載の二次電池の残存容量演算装置である。
【００１７】
請求項６に記載の発明は、前記二次電池がニッケル−金属水素化物電池であることを特徴とする請求項１〜請求項５のいずれかの請求項に記載の二次電池の残存容量演算装置である。
【００１８】
請求項７に記載の発明は、温度を測定する温度測定ステップと、自己放電時の温度と自己放電開始から現在までの経過時間とをパラメータとする表又は関数に基づいて導出した自己放電電気量と、充電と自己放電の繰り返しによって生じたメモリ効果によって実効的に減少する容量と、に基づいて二次電池の残存容量を推定する残存容量推定ステップと、前記残存容量の情報を出力する出力ステップと、を有することを特徴とする二次電池の残存容量演算方法である。
【００１９】
請求項８に記載の発明は、前記温度測定ステップは、更に充電完了時点から次の充電開始時点までの自己放電期間毎の前記温度の平均値を算出するステップと、完全放電後における各自己放電期間の前記平均値の中で最大の値である最大自己放電期間平均温度を抽出するステップとを更に有し、前記残存容量推定ステップは、前記最大自己放電期間平均温度をパラメータとする非線形変換の表又は関数に基づいて前記メモリ効果によって実効的に減少する容量を導出するステップを有する、ことを特徴とする請求項７に記載の二次電池の残存容量演算方法である。
【００２０】
請求項９に記載の発明は、前記二次電池が完全放電した後に、前記二次電池が自己放電状態から充電状態に変化した回数又は充電状態から自己放電状態に変化した回数をカウントするカウントステップと、前記回数をパラメータとする非線形変換の表又は関数に基づいて前記メモリ効果によって実効的に減少する容量を導出するステップと、を更に有することを特徴とする請求項７又は請求項８に記載の二次電池の残存容量演算方法である。
【００２１】
請求項１０に記載の発明は、前記二次電池が、１又は複数の二次電池セルを直列に接続した直列接続電池群を複数個並列接続した二次電池パックであり、前記温度測定ステップは、少なくとも２以上の前記直列接続電池群の温度を測定し、２以上の前記直列接続電池群の温度の平均値を算出する温度平均化ステップを更に有し、前記残存容量推定ステップは、前記温度平均化部が出力する平均値を温度の値として、前記自己放電電気量及び前記メモリ効果によって実効的に減少する容量の少なくともいずれか１つを導出するステップを、更に有することを特徴とする請求項７〜請求項９のいずれかの請求項に記載の二次電池の残存容量演算方法である。
【００２２】
請求項１１に記載の発明は、前記二次電池が、１又は複数の二次電池セルを直列に接続した直列接続電池群を複数個並列接続した二次電池パックであり、前記温度測定ステップは、少なくとも２以上の前記直列接続電池群の温度を測定し、前記残存容量推定ステップは、それぞれの前記直列接続電池群毎の残存容量を推定し、それぞれの前記直列接続電池群毎の残存容量に基づいて二次電池全体の前記残存容量を推定する、ことを特徴とする請求項７〜請求項９のいずれかの請求項に記載の二次電池の残存容量演算方法である。
【００２３】
請求項１２に記載の発明は、前記二次電池がニッケル−金属水素化物電池であることを特徴とする請求項７〜請求項１１のいずれかの請求項に記載の二次電池の残存容量演算方法である。
本発明は、高い精度で二次電池の残存容量を推定する残存容量演算装置及び残存容量演算方法を実現する。本発明は、充電と自己放電の繰り返しによって生じるメモリ効果を有する電池である、ニッケル−金属水素化物電池において、特に有効である。
【００２４】
【発明の実施の形態】
以下本発明の実施をするための最良の形態を具体的に示した実施例について、図面とともに記載する。
【００２５】
《実施例１》
図１、図２、図３、図４、図６及び図７を用いて、本発明の実施例１の残存容量演算装置及びその残存容量演算方法を説明する。
【００２６】
図１は、本発明の実施例１の残存容量演算装置１００を含むバックアップ電源用電池管理装置の構成図である。図１において、１００は残存容量演算装置、１０１は二次電池、１０２は電源監視制御部、１０５は放電器、１０６は充電器、１０７は表示部、１０８は商用電源、１０９は整流器、１１０は負荷である。残存容量演算装置１００は、電池監視部１０３及び温度測定部１０４を有する。電池監視部１０３は、入出力部１１１、残存容量推定部１１２、タイマ部１１３、カウント部１１４を有する。
【００２７】
本発明の発明者は、不完全放電と充電の繰り返し時のみならず、放置による自己放電と充電の繰り返しによっても、二次電池にメモリ効果が生じ、容量が実効的に減少することを見いだした。図６は充電と自己放電の繰り返しによって生じる二次電池のメモリ効果を説明する概念図である。二次電池が満充電された時刻Ｔ１以後、残存容量は自己放電によって減少する。残存容量がある閾値を下回った時点から補充電を開始する。以後、完全放電を含まない自己放電と充電とを繰り返す。このような場合、時刻Ｔ３に電池を完全放電させると、前回の完全放電時よりもΔＳＯＣだけ放電電気量（電池の実効的な容量）が減少する。ΔＳＯＣがメモリ効果によって実効的に減少した電池の容量である。自己放電の期間（例えば２ヶ月）は補充電に要する時間（例えば８時間）と較べてはるかに長い。１枚の図に全てを表示する都合上、図６において、自己放電の期間を補充電に要する時間とほぼ同じ幅で表示している。
【００２８】
二次電池１０１は、互いに直列に接続されている複数の二次電池セル（図示しない。）、あるいは一つの二次電池セル（図示しない。）から構成されている。それぞれの二次電池セルは、完全放電を含まない充放電を繰り返した場合や、充電と自己放電（放置）を繰り返した場合に放電容量が低下する現象であるメモリ効果を有する。実施例１において二次電池１０１はニッケル−金属水素化物電池である。
【００２９】
残存容量推定部１１２は、二次電池１０１の残存容量を推定する。入出力部１１１は残存容量の情報を電源監視制御部１０２に送信する。二次電池１０１の残存容量の情報は、表示部１０７に表示される。表示方法は、定量的な表示（例えばＡｈを単位とする値の表示）であっても良く、定性的な表示（例えば赤色発光ダイオードを点滅させて残存容量が少ないことを示す表示）でも良い。残存容量の情報の出力は、例えば直接ユーザが視覚的又は聴覚的に認識可能なように表示しても良く、ホスト装置等に残存容量の情報を送信しても良い。
【００３０】
温度測定部１０４は、二次電池１０１の内部温度、二次電池１０１の表面温度又は雰囲気温度のいずれかを測定し、電池監視部１０３の入出力部１１１に送信する。実施例において温度測定部１０４は二次電池１０１の表面温度Ｔｂを測定する。
【００３１】
通常、負荷１１０には商用電源１０８が供給されている。商用電源１０８からの交流電流は整流器１０９で直流電流に変換され、負荷１１０に供給される。商用電源１０８が供給されている期間、二次電池１０１は間欠充電されている。この期間二次電池１０１は使用されないが、放置中の自己放電によりその残存容量は少しずつ減少する。二次電池１０１の残存容量が所定の閾値まで減ると、二次電池は充電される。停電時は、二次電池１０１がバックアップ用電源として働く。
【００３２】
図２は、本発明の実施例１の残存容量演算装置１００を含むバックアップ電源用電池管理装置の、二次電池１０１の充電状態でのフローチャートである。残存容量演算装置１００は、使用されず自己放電をしている二次電池１０１の残存容量を推定している。残存容量が閾値以下になると、ステップ２０１で電池監視部１０３は入出力部１１１から電源監視制御部１０２に充電指令を送信する。ステップ２０２で電池監視部１０３は、前回の放電が完全放電だったか否か判断する。完全放電だった場合はステップ２０３に進み、カウント部１１４は自己放電回数のカウンタｎに初期値０を代入する。完全放電によってメモリ効果による容量減少は回復するため、ｎを完全放電の後にリセットする。前回の放電が完全放電ではなかった場合、つまり、放置（無負荷状態）による自己放電だった場合はステップ２２１に進み、カウント部１１４はカウンタｎに１を加算する。ステップ２０４で電源監視制御部１０２は充電指令を受信し、充電器１０６をＯＮにする。これにより、二次電池１０１の充電が開始する。温度測定部１０４が測定した温度Ｔｂが入出力部１１１に送信される（ステップ２０５）。残存容量推定部１１２は、充電期間中の残存容量（増加する。）を推定し（ステップ２０６）、入出力部１１１から電源監視制御部１０２に送信する。電源監視制御部１０２は、残存容量推定値を表示部１０７に送信する（ステップ２０７）。
【００３３】
二次電池１０１の温度Ｔｂは充電が進むにつれて上昇し、その上昇率は充電完了直前に急激に大きくなる。従って、電池温度Ｔｂの上昇率から満充電を検出できる。電池監視部１０３はステップ２０８で温度測定部１０４が測定した温度Ｔｂの時間変化率ｄＴｂ／ｄｔを計算し（ｔは時間である。）、閾値以上か否か判断する。閾値未満の場合はステップ２０５に戻り、充電を継続する。閾値以上の場合はステップ２０９に進む。ステップ２０９で電池監視部１０３は充電停止指令を入出力部１１１から電源監視制御部１０２に送信する。電源監視制御部１０２は、充電停止指令を受信し、充電器１０６をＯＦＦにする。これにより、二次電池１０１の充電が終了する。ステップ２１０に進み自己放電状態のフローチャート（図３）に進む。
【００３４】
図３は、本発明の実施例１の残存容量演算装置１００を含むバックアップ電源用電池管理装置の、二次電池１０１の放置による自己放電状態でのフローチャートである。ステップ３０１で、温度測定部１０４が測定した温度Ｔｂが入出力部１１１に送信される。ステップ３０２で、タイマ部１１３が自己放電開始から現在までの経過時間を測定する。前回の残存容量の推定時からの経過時間が所定の単位時間（例えば１日）を超えたときに、ステップ３０３に進む。
【００３５】
ステップ３０３で、残存容量推定部１１２は、前回、残存容量を推定した時からの自己放電電気量を算出する。残存容量推定部１１２は、自己放電開始からの経過時間、自己放電時の温度及び二次電池１０１の種類をパラメータとする、自己放電率の表又は関数を記憶しており、自己放電電気量の算出に使用する。自己放電電気量の算出には、温度測定部１０４が自己放電期間中に測定した温度Ｔｂの、ステップ３０３実行時での過去１日分の平均値を、自己放電時の温度として使用する。
【００３６】
図７は、自己放電中の温度が一定の場合の、ニッケル−金属水素化物電池の自己放電による容量維持率の変化特性図（自己放電特性曲線）である。図７において、縦軸が容量維持率（単位％）＝（１−自己放電率）×１００＝｛（満充電容量−自己放電容量）／満充電容量｝×１００、横軸が経過時間である。各曲線は自己放電時の温度をパラメータとする。一定の経過時間を経た時点における単位時間当たりの自己放電電気量は、温度が高いほど大きい。
【００３７】
ステップ３０４で残存容量推定部１１２は、前回計算した残存容量から自己放電電気量を差し引き、残存容量の値を更新し、入出力部１１１から電源監視制御部１０２に送信する。電源監視制御部１０２は、残存容量推定値を表示部１０７に送信する（ステップ３０５）。表示部１０７は、残存容量の情報を表示する。電池監視部１０３はステップ３０６で、残存容量が閾値以下かどうか判断する。閾値より大きい場合はステップ３０１に戻る。つまり、二次電池１０１の自己放電が継続する。閾値以下の場合はステップ３０７に進む。残存容量推定部１１２は、充電と自己放電の繰り返しによって生じたメモリ効果による容量減少量（自己放電回数がｎ回から（ｎ＋１）回に増加することによって更に減少した容量Ｑ・ΔＧｍである。Ｑはメモリ効果がない状態での満充電時の電池容量、Ｇｍはメモリ効果による容量減少量のＱに対する率（容量減少率）、ΔＧｍは自己放電回数が１回増加する毎に発生するＧｍの変化値である。）を推定し、残存容量（ｎ回の自己放電のメモリ効果による容量減少量を考慮した値）から差し引く。推定方法は後で述べる。放置を中止し、充電状態のフローチャート（図２）へ進む。
【００３８】
上記メモリ効果は放電時電池温度が高温であるほど促進される。本発明の実施例１では、図３のステップ３０７で残存容量推定部１１２が、メモリ効果による容量減少量を、自己放電時の電池温度に基づいて推定する。図４は、本発明の実施例１の残存容量に対するメモリ効果による容量減少分の補正方法を示すフローチャートである。ステップ４０１で、自己放電期間中（補充電完了後、自己放電を行い次の補充電を開始するまでの期間）の日平均電池温度を１日ごとに計算し、平均化する。つまり、ｎ回目の自己放電期間中の平均電池温度を算出する。ステップ４０２で、ｎ回の自己放電期間中のそれぞれの平均電池温度の最大値Ｔｍ（℃）を求める。表１は、Ｔｍに対する、メモリ効果による容量減少率Ｇｍの表の一例である。実施例１において、自己放電回数ｎが１以上であれば、メモリ効果による容量減少率Ｇｍはｎに依存せず一定である（表１に示すように、Ｔｍには依存する。ｎ＝０では容量減少率Ｇｍ＝０である。）と近似する（表２に示すように、この近似の精度はかなり高い。）。残存容量推定部１１２は、予めこの表を記憶している。ステップ４０３で残存容量推定部１１２は、表１から自己放電期間中平均電池温度の最大値Ｔｍに対する、メモリ効果による容量減少率Ｇｍを読み取る。対応するＴｍが表中にない場合は、補間して求める。
【００３９】
【表１】

【００４０】
読み取った容量減少率Ｇｍ（ｎｅｗ）が現在設定している容量減少率Ｇｍ（ｎｏｗ）よりも大きい場合（Ｇｍ（ｎｅｗ）＞Ｇｍ（ｎｏｗ））、容量減少率Ｇｍの設定値を読み取った新たな値に置き換える。新たな値と前の値との差分がΔＧｍである（ΔＧｍ＝Ｇｍ（ｎｅｗ）−Ｇｍ（ｎｏｗ））。読み取った容量減少率Ｇｍ（ｎｅｗ）が現在設定している容量減少率Ｇｍ（ｎｏｗ）以下の場合（Ｇｍ（ｎｅｗ）≦Ｇｍ（ｎｏｗ））、容量減少率Ｇｍの設定値を変えない。ステップ４０４で、満充電時の電池容量ＱとΔＧｍの積から容量減少量を計算する。ステップ４０５で残存容量から容量減少量を差し引いて新しい残存容量とする（残存容量＝残存容量−Ｑ・ΔＧｍ）。このようにして計算された残存容量は（メモリ効果のない状態での残存容量）・（１−Ｇｍ）になる。処理を終了する。
【００４１】
図４の処理により、補充電開始時以降の残存容量は、メモリ効果による目減りを差し引いた値になる。従って、補充電終了時（満充電時）の残存容量はＱ・（１−Ｇｍ）に補正される。上記の様に、実施例１においては、自己放電期間中の平均電池温度の最大値と自己放電開始から現在までの経過時間とをパラメータとする表（関数であっても良い。）に基づいて導出した自己放電時の自己放電電気量と、メモリ効果によって実効的に減少する容量と、に基づいて二次電池の残存容量を正確に推定する。従来の残存容量演算方法と比較して、実際に使用できる容量と推定した残存容量とのズレを少なくできる。
【００４２】
メモリ効果によって実効的に減少する容量を導出するためのパラメータとして、任意の方法で求めた電池温度を使用してもよい。好ましくは、実施例１に示すように、自己放電期間中の平均電池温度の最大値Ｔｍを使用し、残存容量の補正を行う。メモリ効果による影響の大きさは、最も高かった電池温度に依存する。実施例の方法により、メモリ効果によって実効的に減少する容量を高い精度で導出できる。また、表１の値を補間して計算できる非線形の関数を使用しても良い。
【００４３】
《実施例２》
図１〜３及び図５を用いて、本発明の実施例２の残存容量演算装置及びその残存容量演算方法を説明する。図１は、本発明の実施例２の残存容量演算装置１００を含むバックアップ電源用電池管理装置の構成図であり、実施例１と同じであるので説明を省略する。図２は、本発明の実施例２の残存容量演算装置の充電状態でのフローチャートである。図３は、本発明の実施例２の残存容量演算装置の放置による自己放電状態でのフローチャートである。これらのフローチャートも実施例１と同じであるため、説明を省略する。
【００４４】
本発明の実施例２では、図３のステップ３０７で残存容量推定部１１２が、メモリ効果による容量減少量を、自己放電の回数及び自己放電期間中の電池温度を使用して推定する。図５は、本発明の実施例２における残存容量に対するメモリ効果による容量減少分の補正方法を示すフローチャートである。表２は、実施例２で使用する自己放電期間中の平均電池温度の最大値Ｔｍと自己放電の回数ｎに対するメモリ効果による容量減少率Ｇｍの表である。残存容量推定部１１２は、予め表２を記憶している。図５のフローチャートは実施例１のステップ４０３がステップ５０１に置き換わったものである。他のステップは実施例１と同じであるので説明を省略する。ステップ５０１で残存容量推定部１１２は、表２から自己放電の回数ｎに対する、メモリ効果による容量減少率Ｇｍを読み取る。対応するｎ及びＴｍが表中にない場合は、補間して求める。
【００４５】
【表２】

【００４６】
読み取った容量減少率Ｇｍ（ｎｅｗ）が現在設定している容量減少率Ｇｍ（ｎｏｗ）よりも大きい場合（Ｇｍ（ｎｅｗ）＞Ｇｍ（ｎｏｗ））、容量減少率Ｇｍの設定値を読み取った新たな値に置き換える。新たな値と前の値との差分がΔＧｍである（ΔＧｍ＝Ｇｍ（ｎｅｗ）−Ｇｍ（ｎｏｗ））。読み取った容量減少率Ｇｍ（ｎｅｗ）が現在設定している容量減少率Ｇｍ（ｎｏｗ）以下の場合（Ｇｍ（ｎｅｗ）≦Ｇｍ（ｎｏｗ））、容量減少率Ｇｍの設定値を変えない。
【００４７】
図５の処理により、補充電開始時以降の残存容量は、メモリ効果による目減りを差し引いた値になる。従って、補充電終了時（満充電時）の残存容量はＱ・（１−Ｇｍ）に補正される。上記の様に、実施例１においては、自己放電時の温度と自己放電開始から現在までの経過時間とをパラメータとする表（関数であっても良い。）に基づいて導出した自己放電時の放電電気量と、メモリ効果によって実効的に減少する容量と、に基づいて二次電池の残存容量を正確に推定する。従来の残存容量演算方法と比較して、実際に使用できる容量と推定した残存容量とのズレを少なくできる。実施例２では、自己放電期間中の電池温度のみならず、自己放電の回数をも残存容量の推定に考慮しているため、実施例１に比べ、より高い精度で残存容量を推定できる。
【００４８】
メモリ効果によって実効的に減少する容量を導出するためのパラメータとして、任意の方法で求めた電池温度を使用してもよい。好ましくは、実施例２に示すように、自己放電期間中の平均電池温度の最大値Ｔｍを使用し、残存容量の補正を行う。メモリ効果による影響の大きさは、最も高かった電池温度に依存する。実施例の方法により、メモリ効果によって実効的に減少する容量を高い精度で導出できる。また、表２の値を補間して計算できる非線形の関数を使用しても良い。自己放電の回数の替わりに補充電の回数を使用しても良い。
【００４９】
《実施例３》
図８を用いて、本発明の実施例３の残存容量演算装置及びその残存容量演算方法を説明する。
実施例１及び実施例２の二次電池１０１は、互いに直列に接続されている複数の二次電池セル、あるいは一つの二次電池セルから構成されている。実施例３の二次電池８０１は、１又は複数の二次電池セルを直列に接続した直列接続電池群を複数個並列接続した二次電池パックである。
【００５０】
図８は、本発明の実施例３の残存容量演算装置８００を含むバックアップ電源用電池管理装置の構成図である。実施例３の残存容量演算装置８００を含むバックアップ電源用電池管理装置は、実施例１及び実施例２の残存容量演算装置１００を含むバックアップ電源用電池管理装置（図１）の二次電池１０１を二次電池パック８０１に置き換え、残存容量演算装置８００に温度平均化部８０４を付け加えたものである。その他の構成は実施例１及び実施例２と同じであるので説明を省略する。二次電池パック８０１は、ｋ個の二次電池セルをそれぞれ直列接続したｎ個の直列接続電池群１〜ｎ（８０１１〜８０１ｎ）を並列接続したものである。直列接続電池群１〜ｎ（８０１１〜８０１ｎ）はそれぞれ、互いに直列に接続されている複数の二次電池セル、あるいは一つの二次電池セルから構成されている。
【００５１】
温度測定部１０４はｎ個の温度センサを有し、各温度センサは直列接続電池群１〜ｎ（８０１１〜８０１ｎ）の表面温度Ｔｂ１〜Ｔｂｎをそれぞれ測定する。温度平均化部８０４は、表面温度Ｔｂ１〜Ｔｂｎを入力し、平均値Ｔｐを計算し、残存容量演算装置８００に温度Ｔｐを送信する。残存容量演算装置８００の残存容量推定部１１２は、受信した温度Ｔｐを、二次電池パック８０１の温度として記憶する。
【００５２】
残存容量推定部１１２は、温度Ｔｐを使用して二次電池パック８０１の残存容量を算出する。算出方法は、実施例２又は実施例３に記載した残存容量演算方法（自己放電電気量の算出方法（図３）及びメモリ効果によって実効的に減少する容量の算出方法（図４又は５）を含む。）において、「温度Ｔｂ」を「温度Ｔｐ」に、「二次電池１０１」を「二次電池パック８０１」に、「温度Ｔｂに基づいて自己放電期間中の平均電池温度の最大値Ｔｍを導出すること」を「温度Ｔｐに基づいて自己放電期間中の平均電池温度の最大値Ｔｍを導出すること」若しくは「温度Ｔｂ１〜Ｔｂｎに基づいて各直列接続電池群の自己放電期間中の平均電池温度の最大値Ｔｍ１〜Ｔｍｎを導出し、それぞれの自己放電期間中の平均電池温度の最大値Ｔｍ１〜Ｔｍｎを平均して自己放電期間中の平均電池温度の最大値Ｔｍを導出すること」に、置き換えた方法と同じであるので、説明を省略する。
【００５３】
二次電池セルを並列接続した電池パックにおいては、直列接続電池群間に温度差が生じる場合がある。残存容量演算においてどの二次電池の温度を測定して測定値を使用するかによって、二次電池パック８０１の残存容量の値が異なる。実施例３によれば、全ての二次電池の温度を平均化した値Ｔｐを二次電池パック８０１の残存容量演算に使用するので、より正確に残存容量を推定できる。
実施例３においては、全ての直列接続電池群の表面温度を測定した。これに代えて、温度測定部１０４は、電池パックのｎ個の直列接続電池群の一部であるｍ個（２≦ｍ＜ｎ）の直列接続電池群の各表面温度を測定しても良い。好ましくは温度測定部１０４は、電池パックの中で物理的にある程度均一に分布した複数（ｍ個）の直列接続電池群の表面温度を測定する。温度平均化部８０４は、ｍ個の表面温度を入力し、その平均値Ｔｐを計算する。
【００５４】
《実施例４》
図９を用いて、本発明の実施例４の残存容量演算装置及びその残存容量演算方法を説明する。図９は、本発明の実施例４の残存容量演算装置９００を含むバックアップ電源用電池管理装置の構成図である。実施例４の残存容量演算装置９００は、実施例３と同様に、１又は複数の二次電池セルを直列に接続した直列接続電池群を複数個並列接続した二次電池パックである二次電池８０１の残存容量を推定し、出力する。実施例４の残存容量演算装置９００は、実施例３の温度平均化部８０４を有しておらず、実施例３の残存容量推定部１１２に代えて残存容量推定部９１２を有する。その他の構成は実施例３と同じであるので説明を省略する。
【００５５】
温度測定部１０４はｎ個の温度センサを有し、各温度センサは直列接続電池群１〜ｎ（８０１１〜８０１ｎ）の表面温度Ｔｂ１〜Ｔｂｎをそれぞれ測定し、測定値を残存容量演算装置９００に送信する。
【００５６】
残存容量演算装置９００の残存容量推定部９１２は、温度測定部１０４から送信された温度Ｔｂ１〜Ｔｂｎを、二次電池パック８０１の各直列接続電池群１〜ｎ（８０１１〜８０１ｎ）の温度として記憶する。
【００５７】
残存容量推定部９１２は、温度Ｔｂ１〜Ｔｂｎを使用して二次電池パック８０１の各直列接続電池群１〜ｎ（８０１１〜８０１ｎ）の残存容量を算出する。算出方法は、実施例２又は実施例３に記載した残存容量演算方法と同じであるので、説明を省略する。残存容量推定部９１２は、各直列接続電池群１〜ｎ（８０１１〜８０１ｎ）の残存容量（残存容量は、パーセント表示した値であるとする。）の平均値を算出し、その平均値を二次電池パック８０１全体の残存容量と推定する。
【００５８】
実施例４においては、全ての直列接続電池群の表面温度を測定した。これに代えて、温度測定部１０４は、電池パックのｎ個の直列接続電池群の一部であるｍ個（２≦ｍ＜ｎ）の直列接続電池群の各表面温度を測定しても良い。好ましくは温度測定部１０４は、電池パックの中で物理的にある程度均一に分布した複数（ｍ個）の直列接続電池群の表面温度を測定する。残存容量推定部９１２は、ｍ個の直列接続電池群の残存容量を算出し、残存容量（残存容量は、パーセント表示した値であるとする。）の平均値を算出し、その平均値を二次電池パック８０１全体の残存容量と推定する。
【００５９】
【発明の効果】
本発明によれば、二次電池の実際に使用できる容量と推定した残存容量とのズレが小さい、二次電池の残存容量を正確に推定する残存容量演算装置及びその残存容量演算方法を実現できるという有利な効果が得られる。
【図面の簡単な説明】
【図１】本発明の実施例１及び実施例２の残存容量演算装置を含むバックアップ電源用電池管理装置の構成図
【図２】本発明の実施例１及び実施例２の残存容量演算装置の充電状態でのフローチャート
【図３】本発明の実施例１及び実施例２の残存容量演算装置の放置による自己放電状態でのフローチャート
【図４】本発明の実施例１の残存容量に対するメモリ効果による容量減少分の補正方法を示すフローチャート
【図５】本発明の実施例２の残存容量に対するメモリ効果による容量減少分の補正方法を示すフローチャート
【図６】充電と自己放電の繰り返しによって生じる二次電池のメモリ効果を説明する概念図
【図７】ニッケル−金属水素化物電池の自己放電による容量維持率の変化特性図
【図８】本発明の実施例３の残存容量演算装置を含むバックアップ電源用電池管理装置の構成図
【図９】本発明の実施例４の残存容量演算装置を含むバックアップ電源用電池管理装置の構成図
【符号の説明】
１００、８００、９００残存容量演算装置
１０１二次電池
１０２電源監視制御部
１０３電池監視部
１０４温度測定部
１０５放電器
１０６充電器
１０７表示部
１０８商用電源
１０９整流器
１１０負荷
１１１入出力部
１１２、９１２残存容量推定部
１１３タイマ部
１１４カウント部
８０１二次電池パック
８０１１直列接続電池群１
８０１ｎ直列接続電池群ｎ
８０４温度平均化部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an apparatus and a method for calculating the remaining capacity of a secondary battery.
[0002]
[Prior art]
Conventionally, lead-acid batteries have often been used as backup power supplies for electronic and electrical equipment, but recently, demand for nickel-metal hydride batteries has been increasing. This is because nickel-metal hydride batteries have a higher energy density and are lighter and smaller than lead-acid batteries.
[0003]
A nickel-metal hydride battery is always charged with a small current (trickle charging), so that its durability is deteriorated. Therefore, intermittent charging is adopted as a charging method. The intermittent charging is a method of performing supplementary charging when the capacity (hereinafter referred to as “remaining capacity”) that can be taken out of the battery by forced discharge or self-discharge by leaving below a threshold value. For example, Japanese Patent Application Laid-Open No. 2000-150,000 discloses a method of managing a backup power supply of Conventional Example 1. Conventional example 1 is a method of managing a backup power supply that calculates the amount of self-discharge electricity during the suspension of charging based on the temperature during suspension of charge of the nickel-hydrogen storage battery, and intermittently charges the amount corresponding to the amount of self-discharge electricity.
[0004]
Nickel-metal hydride batteries have the property that the capacity is effectively reduced by the memory effect when charging and incomplete discharging are repeated. Therefore, when a nickel-metal hydride battery is used in an apparatus that repeatedly charges and discharges, how to consider the memory effect in the charge and discharge control becomes a problem.
[0005]
Japanese Patent Application Laid-Open No. 9-129267 discloses a storage battery state management device of Conventional Example 2. Conventional example 2 is a storage battery state management device that calculates the remaining capacity of a nickel-metal hydride storage battery (nickel-metal hydride battery) used as a power supply for driving a moving body such as an electric vehicle. The remaining capacity calculated from the discharge voltage, battery temperature, and discharge current of the storage battery is corrected according to the number of times the storage battery has been charged and discharged.
[0006]
Japanese Patent Application Laid-Open No. 2001-126776 discloses a method of displaying the capacity of a secondary battery of Conventional Example 3. Conventional example 3 is a secondary battery capacity display method in which the number of times of charge or the number of times of discharge are counted after refreshing a secondary battery having a memory effect, and when the count value increases, the remaining capacity is corrected and displayed. is there. The correction amount is an amount proportional to the count value.
[0007]
[Patent Document 1]
JP-A-2000-150,000
[Patent Document 2]
JP-A-9-129267
[Patent Document 3]
JP 2001-126776 A
[0008]
[Problems to be solved by the invention]
The backup battery is not usually used, and is used in an emergency such as a power failure. When a backup battery that had been estimated to have a certain remaining capacity was used during a power outage, if the actual remaining capacity was empty, the device that was to be supplied with power from the backup battery could not be moved, causing serious trouble. I do. Therefore, the remaining capacity of the battery must always be accurately grasped.
[0009]
The inventor of the present invention has found that the rechargeable battery has a memory effect and the capacity is effectively reduced not only when the incomplete discharge and the charge are repeated but also when the self-discharge and the charge are repeatedly performed by leaving the battery. . At the time of "discharge", a current is supplied from the secondary battery to the external load, but not at the time of "self-discharge". The methods described in Conventional Examples 2 and 3 consider a memory effect caused by repetition of discharging and charging when calculating the remaining capacity of the secondary battery. However, the memory effect caused by the repetition of self-discharge and charge has not been taken into account when calculating the remaining capacity of the secondary battery.
[0010]
The intermittent charging of the backup power supply described in Conventional Example 1 is a repetition of self-discharge and supplementary charging due to being left unattended. In the method of managing the backup power supply of the first conventional example, only the temperature correction is performed on the amount of self-discharge electricity during the suspension of charging, and the decrease due to the memory effect is not corrected. Therefore, there was a difference between the estimated remaining capacity and the actually usable capacity.
[0011]
The present invention solves the above-mentioned conventional problems, and considers a memory effect caused by repetition of charging and self-discharging, and accurately estimates a remaining capacity of a secondary battery, and a remaining-capacity calculating device for the same. It is an object to provide a capacity calculation method.
[0012]
[Means for Solving the Problems]
In order to solve the above problems, the present invention has the following configurations.
The invention according to claim 1 is a temperature measurement unit for measuring a temperature, and a self-discharge electricity amount derived based on a table or a function using a temperature at the time of self-discharge and an elapsed time from the start of self-discharge to the present as parameters. A remaining capacity estimating unit for estimating the remaining capacity of the secondary battery based on a capacity that is effectively reduced by a memory effect caused by repetition of charging and self-discharging; and an output unit that outputs information on the remaining capacity. And an apparatus for calculating the remaining capacity of a secondary battery.
The information on the remaining capacity output from the output unit is arbitrary. The remaining capacity information is, for example, an 8-bit digital value representing the remaining capacity, an analog voltage proportional to the remaining capacity, or a low level when the remaining capacity is equal to or less than a predetermined threshold, and a high level when the remaining capacity is larger than the predetermined threshold. It may be a 1-bit digital value. The output of the information on the remaining capacity includes, for example, transmitting a transmission signal having the information on the remaining capacity through a wired or wireless communication line, displaying the image, displaying the sound, or displaying the image using a light emitting element (eg, an LED (Light Emitting Diode)). It may be.
[0013]
In the invention according to claim 2, the temperature measurement unit further calculates an average value of the temperature for each self-discharge period from a charge completion time to a next charge start time, and calculates an average value of each self-discharge period after complete discharge. The maximum self-discharge period average temperature, which is the maximum value among the average values, is extracted, and the remaining capacity estimating unit is further based on a table or function of a non-linear conversion using the maximum self-discharge period average temperature as a parameter. The apparatus according to claim 1, wherein the capacity that is effectively reduced by the memory effect is derived.
[0014]
The invention according to claim 3, wherein the counting unit counts the number of times the secondary battery changes from a self-discharge state to a charge state or the number of times changes from a charge state to a self-discharge state after the secondary battery is completely discharged. And the remaining capacity estimating unit further derives a capacity that is effectively reduced by the memory effect based on a table or a function of a non-linear conversion using the number of times as a parameter. An apparatus for calculating a remaining capacity of a secondary battery according to claim 2.
[0015]
The invention according to claim 4 is the secondary battery, wherein the secondary battery is a secondary battery pack in which a plurality of series-connected battery groups in which one or a plurality of secondary battery cells are connected in series are connected in parallel. A temperature averaging unit that measures a temperature of at least two or more of the series-connected battery groups and calculates an average value of the temperatures of the two or more of the series-connected battery groups; The average value output from the averaging unit is taken as a temperature value, and at least one of the self-discharged electricity amount and the capacity that is effectively reduced by the memory effect is derived. An apparatus for calculating the remaining capacity of a secondary battery according to claim 3.
[0016]
The invention according to claim 5, wherein the secondary battery is a secondary battery pack in which a plurality of series-connected battery groups in which one or a plurality of secondary battery cells are connected in series are connected in parallel, and the temperature measurement unit is Measuring the temperature of at least two or more series-connected battery groups, the remaining capacity estimating unit estimates the remaining capacity of each of the series-connected battery groups, and calculates the remaining capacity of each of the series-connected battery groups. The remaining capacity calculation device for a secondary battery according to any one of claims 1 to 3, wherein the remaining capacity of the whole secondary battery is estimated based on the remaining capacity.
[0017]
According to a sixth aspect of the present invention, the secondary battery is a nickel-metal hydride battery, and the remaining capacity calculation of the secondary battery according to any one of the first to fifth aspects is provided. Device.
[0018]
The invention according to claim 7 is a temperature measurement step of measuring a temperature, and a self-discharge electricity amount derived based on a table or a function using a temperature at the time of self-discharge and an elapsed time from the start of self-discharge to the present as parameters. A remaining capacity estimating step of estimating a remaining capacity of the secondary battery based on a capacity that is effectively reduced by a memory effect caused by repetition of charging and self-discharging; and an output step of outputting information on the remaining capacity. And a method for calculating the remaining capacity of the secondary battery.
[0019]
The temperature measuring step may further comprise: calculating an average value of the temperature for each self-discharge period from the time of completion of charging to the time of starting the next charging; Extracting a maximum self-discharge period average temperature that is a maximum value among the average values of the periods, and the remaining capacity estimation step includes a step of performing nonlinear conversion using the maximum self-discharge period average temperature as a parameter. The method according to claim 7, further comprising deriving a capacity that is effectively reduced by the memory effect based on a table or a function.
[0020]
A counting step for counting the number of times the secondary battery changes from a self-discharge state to a charge state or the number of times changes from a charge state to a self-discharge state after the secondary battery is completely discharged. 9. The method according to claim 7, further comprising: deriving a capacity that is effectively reduced by the memory effect based on a table or a function of a non-linear conversion using the number of times as a parameter. 10. Is a method for calculating the remaining capacity of the secondary battery.
[0021]
The invention according to claim 10 is the secondary battery, wherein the secondary battery is a secondary battery pack in which a plurality of series-connected battery groups in which one or a plurality of secondary battery cells are connected in series are connected in parallel. A temperature averaging step of measuring a temperature of at least two or more of the series-connected battery groups and calculating an average value of the temperatures of the two or more of the series-connected battery groups; The method further comprising deriving at least one of the self-discharged electricity amount and the capacity that is effectively reduced by the memory effect, using an average value output by the averaging unit as a temperature value. A method for calculating the remaining capacity of a secondary battery according to any one of claims 7 to 9.
[0022]
The invention according to claim 11 is the secondary battery, wherein the secondary battery is a secondary battery pack in which a plurality of series-connected battery groups in which one or a plurality of secondary battery cells are connected in series are connected in parallel, and the temperature measuring step includes: Measuring the temperature of at least two or more of the series-connected battery groups, and estimating the remaining capacity of each of the series-connected battery groups, and calculating the remaining capacity of each of the series-connected battery groups. The method according to any one of claims 7 to 9, wherein the remaining capacity of the entire secondary battery is estimated based on the remaining capacity.
[0023]
According to a twelfth aspect of the present invention, the secondary battery is a nickel-metal hydride battery, and the remaining capacity of the secondary battery according to any one of the seventh to eleventh aspects is calculated. Is the way.
The present invention realizes a remaining capacity calculation device and a remaining capacity calculation method for estimating the remaining capacity of a secondary battery with high accuracy. The present invention is particularly effective in a nickel-metal hydride battery, which is a battery having a memory effect caused by repetition of charging and self-discharging.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment specifically showing the best mode for carrying out the present invention will be described below with reference to the drawings.
[0025]
<< Example 1 >>
First Embodiment A remaining capacity calculation device and a remaining capacity calculation method according to a first embodiment of the present invention will be described with reference to FIGS. 1, 2, 3, 4, 6, and 7. FIG.
[0026]
FIG. 1 is a configuration diagram of a backup power supply battery management device including a remaining capacity calculation device 100 according to a first embodiment of the present invention. In FIG. 1, 100 is a remaining capacity calculation device, 101 is a secondary battery, 102 is a power supply monitoring and control unit, 105 is a discharger, 106 is a charger, 107 is a display unit, 108 is a commercial power supply, 109 is a rectifier, 110 is It is a load. The remaining capacity calculation device 100 includes a battery monitoring unit 103 and a temperature measurement unit 104. Battery monitoring section 103 has input / output section 111, remaining capacity estimation section 112, timer section 113, and count section 114.
[0027]
The inventor of the present invention has found that the rechargeable battery has a memory effect and the capacity is effectively reduced not only when the incomplete discharge and the charge are repeated but also when the self-discharge and the charge are repeatedly performed by leaving the battery. . FIG. 6 is a conceptual diagram illustrating a memory effect of a secondary battery caused by repetition of charging and self-discharging. After time T1 when the secondary battery is fully charged, the remaining capacity decreases due to self-discharge. Supplementary charging is started when the remaining capacity falls below a certain threshold. Thereafter, the self-discharge and the charge that do not include the complete discharge are repeated. In such a case, when the battery is completely discharged at time T3, the amount of discharged electricity (effective capacity of the battery) is reduced by ΔSOC as compared with the time of the previous complete discharge. ΔSOC is the battery capacity that has been effectively reduced by the memory effect. The self-discharge period (for example, two months) is much longer than the time required for supplementary charge (for example, eight hours). In FIG. 6, the self-discharge period is displayed with substantially the same width as the time required for the supplementary charge for the sake of convenience of displaying all in one figure.
[0028]
The secondary battery 101 includes a plurality of secondary battery cells (not shown) connected in series with each other or one secondary battery cell (not shown). Each secondary battery cell has a memory effect that is a phenomenon in which the discharge capacity is reduced when charging and discharging not including complete discharge are repeated, or when charging and self-discharging (leaving) are repeated. In the first embodiment, the secondary battery 101 is a nickel-metal hydride battery.
[0029]
The remaining capacity estimating unit 112 estimates the remaining capacity of the secondary battery 101. The input / output unit 111 transmits information on the remaining capacity to the power supply monitoring control unit 102. Information on the remaining capacity of the secondary battery 101 is displayed on the display unit 107. The display method may be a quantitative display (for example, display of a value in units of Ah) or a qualitative display (for example, a display in which a red light-emitting diode flashes to indicate that the remaining capacity is low). The output of the remaining capacity information may be displayed so that the user can visually or audibly recognize the remaining capacity, or the remaining capacity information may be transmitted to a host device or the like.
[0030]
The temperature measuring unit 104 measures any of the internal temperature of the secondary battery 101, the surface temperature of the secondary battery 101, and the ambient temperature, and transmits the measured temperature to the input / output unit 111 of the battery monitoring unit 103. In the embodiment, the temperature measuring unit 104 measures the surface temperature Tb of the secondary battery 101.
[0031]
Usually, the commercial power supply 108 is supplied to the load 110. The AC current from the commercial power supply 108 is converted into a DC current by the rectifier 109 and supplied to the load 110. While the commercial power supply 108 is being supplied, the secondary battery 101 is intermittently charged. During this period, the secondary battery 101 is not used, but its remaining capacity gradually decreases due to self-discharge during standing. When the remaining capacity of the secondary battery 101 decreases to a predetermined threshold, the secondary battery is charged. During a power outage, the secondary battery 101 works as a backup power supply.
[0032]
FIG. 2 is a flowchart of the backup power supply battery management device including the remaining capacity calculation device 100 according to the first embodiment of the present invention in a state where the secondary battery 101 is charged. The remaining capacity calculation device 100 estimates the remaining capacity of the secondary battery 101 that is not used and is self-discharging. When the remaining capacity becomes equal to or less than the threshold, the battery monitoring unit 103 transmits a charging command from the input / output unit 111 to the power supply monitoring control unit 102 in step 201. In step 202, the battery monitoring unit 103 determines whether the previous discharge was a complete discharge. If it is a complete discharge, the process proceeds to step 203, where the counting unit 114 substitutes an initial value 0 for a self-discharge counter n. Since the capacity reduction due to the memory effect is recovered by the complete discharge, n is reset after the complete discharge. If the previous discharge was not a complete discharge, that is, if it was a self-discharge due to neglect (no load state), the process proceeds to step 221 and the counting unit 114 adds 1 to the counter n. In step 204, the power supply monitoring control unit 102 receives the charging command and turns on the charger 106. Thus, charging of the secondary battery 101 starts. The temperature Tb measured by the temperature measuring unit 104 is transmitted to the input / output unit 111 (Step 205). The remaining capacity estimating unit 112 estimates the remaining capacity (increases) during the charging period (step 206), and transmits it from the input / output unit 111 to the power supply monitoring control unit 102. The power supply monitoring control unit 102 transmits the estimated remaining capacity to the display unit 107 (Step 207).
[0033]
The temperature Tb of the secondary battery 101 increases as charging progresses, and the rate of increase rapidly increases immediately before charging is completed. Therefore, full charge can be detected from the rate of increase of the battery temperature Tb. The battery monitoring unit 103 calculates a time rate of change dTb / dt of the temperature Tb measured by the temperature measuring unit 104 in step 208 (t is time), and determines whether or not it is equal to or greater than a threshold. If the difference is less than the threshold, the process returns to step 205 to continue charging. If it is equal to or greater than the threshold, the process proceeds to step 209. In step 209, the battery monitoring unit 103 transmits a charge stop command from the input / output unit 111 to the power supply monitoring control unit 102. The power supply monitoring control unit 102 receives the charge stop command and turns off the charger 106. Thereby, the charging of the secondary battery 101 ends. The process proceeds to step 210 and proceeds to the self-discharge state flowchart (FIG. 3).
[0034]
FIG. 3 is a flowchart of the backup power supply battery management device including the remaining capacity calculation device 100 according to the first embodiment of the present invention in a self-discharge state when the secondary battery 101 is left unattended. In step 301, the temperature Tb measured by the temperature measuring unit 104 is transmitted to the input / output unit 111. In step 302, the timer unit 113 measures the elapsed time from the start of self-discharge to the present. When the elapsed time from the previous estimation of the remaining capacity exceeds a predetermined unit time (for example, one day), the process proceeds to step 303.
[0035]
In step 303, the remaining capacity estimating unit 112 calculates the amount of self-discharged electricity since the last time the remaining capacity was estimated. The remaining capacity estimating unit 112 stores a table or a function of the self-discharge rate using the time elapsed from the start of the self-discharge, the temperature at the time of the self-discharge, and the type of the secondary battery 101 as parameters. Used for calculation. For calculation of the amount of self-discharge, the average value of the temperature Tb measured by the temperature measurement unit 104 during the self-discharge period for the past one day when the step 303 is executed is used as the temperature at the time of self-discharge.
[0036]
FIG. 7 is a change characteristic diagram (self-discharge characteristic curve) of the capacity retention ratio due to the self-discharge of the nickel-metal hydride battery when the temperature during the self-discharge is constant. In FIG. 7, the vertical axis represents the capacity retention rate (unit%) = (1−self-discharge rate) × 100 = {(full charge capacity−self-discharge capacity) / full charge capacity} × 100, and the horizontal axis represents elapsed time. . Each curve uses the temperature at the time of self-discharge as a parameter. The amount of self-discharge electricity per unit time at the time when a certain elapsed time has elapsed is higher as the temperature is higher.
[0037]
In step 304, the remaining capacity estimating unit 112 updates the value of the remaining capacity by subtracting the amount of self-discharge from the previously calculated remaining capacity, and transmits the value from the input / output unit 111 to the power monitoring control unit 102. The power monitoring control unit 102 transmits the estimated remaining capacity to the display unit 107 (step 305). The display unit 107 displays remaining capacity information. In step 306, the battery monitoring unit 103 determines whether the remaining capacity is equal to or less than a threshold. If it is larger than the threshold value, the process returns to step 301. That is, self-discharge of the secondary battery 101 continues. If it is equal to or smaller than the threshold, the process proceeds to step 307. The remaining capacity estimating unit 112 calculates the capacity decrease amount due to the memory effect caused by the repetition of the charge and the self-discharge (the capacity Q · ΔGm which is further reduced as the number of self-discharge increases from n to (n + 1) times. Is the battery capacity at full charge in the absence of the memory effect, Gm is the ratio of the amount of capacity reduction due to the memory effect to Q (capacity reduction rate), and ΔGm is the change in Gm that occurs each time the number of self-discharges increases. Is estimated and subtracted from the remaining capacity (a value that takes into account the amount of capacity reduction due to the memory effect of n self-discharges). The estimation method will be described later. The leaving is stopped, and the process proceeds to the flowchart of the charging state (FIG. 2).
[0038]
The memory effect is promoted as the battery temperature at the time of discharge increases. In the first embodiment of the present invention, the remaining capacity estimating unit 112 estimates the amount of capacity reduction due to the memory effect in step 307 of FIG. 3 based on the battery temperature at the time of self-discharge. FIG. 4 is a flowchart illustrating a method of correcting the remaining capacity according to the first embodiment of the present invention for the capacity reduction due to the memory effect. In step 401, the daily average battery temperature during the self-discharge period (a period from completion of supplementary charge to self-discharge and start of the next supplementary charge) is calculated every day and averaged. That is, the average battery temperature during the n-th self-discharge period is calculated. In step 402, the maximum value Tm (° C.) of each average battery temperature during n self-discharge periods is determined. Table 1 is an example of a table of the capacity reduction rate Gm due to the memory effect with respect to Tm. In Example 1, when the number of self-discharges n is 1 or more, the capacity reduction rate Gm due to the memory effect is constant without depending on n (as shown in Table 1, it depends on Tm. When n = 0, The capacity reduction rate Gm is 0.) (The accuracy of this approximation is quite high as shown in Table 2). The remaining capacity estimation unit 112 stores this table in advance. In step 403, the remaining capacity estimating unit 112 reads the capacity reduction rate Gm due to the memory effect with respect to the maximum value Tm of the average battery temperature during the self-discharge period from Table 1. If the corresponding Tm is not in the table, it is obtained by interpolation.
[0039]
[Table 1]

[0040]
When the read capacity reduction rate Gm (new) is larger than the currently set capacity reduction rate Gm (now) (Gm (new)> Gm (now)), a new value obtained by reading the set value of the capacity reduction rate Gm is used. Replace with a value. The difference between the new value and the previous value is ΔGm (ΔGm = Gm (new) −Gm (now)). When the read capacity reduction rate Gm (new) is equal to or smaller than the currently set capacity reduction rate Gm (now) (Gm (new) ≦ Gm (now)), the set value of the capacity reduction rate Gm is not changed. In step 404, the amount of capacity reduction is calculated from the product of the battery capacity Q at full charge and ΔGm. In step 405, the amount of capacity reduction is subtracted from the remaining capacity to obtain a new remaining capacity (remaining capacity = remaining capacity−Q · ΔGm). The remaining capacity calculated in this way is (remaining capacity without a memory effect) · (1−Gm). The process ends.
[0041]
By the processing in FIG. 4, the remaining capacity after the start of the supplementary charge has a value obtained by subtracting the loss due to the memory effect. Therefore, the remaining capacity at the end of the supplementary charge (at the time of full charge) is corrected to Q · (1−Gm). As described above, in the first embodiment, based on the table (may be a function) in which the maximum value of the average battery temperature during the self-discharge period and the elapsed time from the start of the self-discharge to the present are parameters. The remaining capacity of the secondary battery is accurately estimated based on the derived self-discharge electricity amount at the time of self-discharge and the capacity that is effectively reduced by the memory effect. Compared with the conventional remaining capacity calculation method, the difference between the actually usable capacity and the estimated remaining capacity can be reduced.
[0042]
As a parameter for deriving the capacity that is effectively reduced by the memory effect, a battery temperature obtained by an arbitrary method may be used. Preferably, as shown in the first embodiment, the remaining capacity is corrected using the maximum value Tm of the average battery temperature during the self-discharge period. The magnitude of the effect of the memory effect depends on the highest battery temperature. According to the method of the embodiment, the capacity effectively reduced by the memory effect can be derived with high accuracy. Also, a non-linear function that can be calculated by interpolating the values in Table 1 may be used.
[0043]
<< Example 2 >>
Second Embodiment A remaining capacity calculation apparatus and a remaining capacity calculation method according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a configuration diagram of a backup power supply battery management device including a remaining capacity calculation device 100 according to a second embodiment of the present invention. FIG. 2 is a flowchart in a state of charge of the remaining capacity calculation device according to the second embodiment of the present invention. FIG. 3 is a flowchart in a self-discharge state when the remaining capacity calculation device according to the second embodiment of the present invention is left unattended. Since these flowcharts are the same as those in the first embodiment, the description is omitted.
[0044]
In the second embodiment of the present invention, the remaining capacity estimating unit 112 estimates the amount of capacity reduction due to the memory effect at step 307 in FIG. 3 using the number of times of self-discharge and the battery temperature during the self-discharge period. FIG. 5 is a flowchart illustrating a method of correcting the amount of capacity reduction due to the memory effect on the remaining capacity according to the second embodiment of the present invention. Table 2 is a table of the maximum value Tm of the average battery temperature during the self-discharge period used in Example 2 and the capacity reduction rate Gm due to the memory effect with respect to the number n of self-discharges. The remaining capacity estimating unit 112 stores Table 2 in advance. In the flowchart of FIG. 5, step 403 of the first embodiment is replaced with step 501. Other steps are the same as those in the first embodiment, and a description thereof will be omitted. In step 501, the remaining capacity estimating unit 112 reads the capacity reduction rate Gm due to the memory effect with respect to the number n of self-discharges from Table 2. If the corresponding n and Tm are not in the table, they are obtained by interpolation.
[0045]
[Table 2]

[0046]
When the read capacity reduction rate Gm (new) is larger than the currently set capacity reduction rate Gm (now) (Gm (new)> Gm (now)), a new value obtained by reading the set value of the capacity reduction rate Gm is used. Replace with a value. The difference between the new value and the previous value is ΔGm (ΔGm = Gm (new) −Gm (now)). When the read capacity reduction rate Gm (new) is equal to or smaller than the currently set capacity reduction rate Gm (now) (Gm (new) ≦ Gm (now)), the set value of the capacity reduction rate Gm is not changed.
[0047]
By the processing in FIG. 5, the remaining capacity after the start of the supplementary charge has a value obtained by subtracting the loss due to the memory effect. Therefore, the remaining capacity at the end of the supplementary charge (at the time of full charge) is corrected to Q · (1−Gm). As described above, in the first embodiment, the self-discharge time derived based on the table (may be a function) using the temperature at the time of self-discharge and the elapsed time from the start of self-discharge to the present as parameters is used. The remaining capacity of the secondary battery is accurately estimated based on the amount of discharged electricity and the capacity that effectively decreases due to the memory effect. Compared with the conventional remaining capacity calculation method, the difference between the actually usable capacity and the estimated remaining capacity can be reduced. In the second embodiment, not only the battery temperature during the self-discharge period but also the number of times of self-discharge is taken into consideration in estimating the remaining capacity, so that the remaining capacity can be estimated with higher accuracy than in the first embodiment.
[0048]
As a parameter for deriving the capacity that is effectively reduced by the memory effect, a battery temperature obtained by an arbitrary method may be used. Preferably, as shown in the second embodiment, the remaining capacity is corrected using the maximum value Tm of the average battery temperature during the self-discharge period. The magnitude of the effect of the memory effect depends on the highest battery temperature. According to the method of the embodiment, the capacity effectively reduced by the memory effect can be derived with high accuracy. Further, a non-linear function that can be calculated by interpolating the values in Table 2 may be used. The number of supplementary charges may be used instead of the number of self-discharges.
[0049]
<< Example 3 >>
Third Embodiment A remaining capacity calculation device and a remaining capacity calculation method according to a third embodiment of the present invention will be described with reference to FIG.
The secondary battery 101 of the first and second embodiments includes a plurality of secondary battery cells connected in series with each other or one secondary battery cell. The secondary battery 801 of the third embodiment is a secondary battery pack in which a plurality of series-connected battery groups in which one or a plurality of secondary battery cells are connected in series are connected in parallel.
[0050]
FIG. 8 is a configuration diagram of a backup power supply battery management device including the remaining capacity calculation device 800 according to the third embodiment of the present invention. The backup power supply battery management device including the remaining capacity calculation device 800 according to the third embodiment uses the secondary battery 101 of the backup power supply battery management device (FIG. 1) including the remaining capacity calculation device 100 according to the first and second embodiments. In this embodiment, a temperature averaging unit 804 is added to the remaining capacity calculation device 800 instead of the secondary battery pack 801. Other configurations are the same as those of the first and second embodiments, and thus description thereof is omitted. The secondary battery pack 801 is formed by connecting n series-connected battery groups 1 to n (8011 to 801n) in which k secondary battery cells are connected in series, respectively. Each of the series-connected battery groups 1 to n (8011 to 801n) includes a plurality of secondary battery cells connected in series to each other or one secondary battery cell.
[0051]
The temperature measurement unit 104 has n temperature sensors, and each temperature sensor measures the surface temperatures Tb1 to Tbn of the series-connected battery groups 1 to n (8011 to 801n), respectively. Temperature averaging section 804 receives surface temperatures Tb1 to Tbn, calculates average value Tp, and transmits temperature Tp to remaining capacity calculating device 800. The remaining capacity estimating unit 112 of the remaining capacity calculation device 800 stores the received temperature Tp as the temperature of the secondary battery pack 801.
[0052]
The remaining capacity estimation unit 112 calculates the remaining capacity of the secondary battery pack 801 using the temperature Tp. The calculation method includes the remaining capacity calculation method (the calculation method of the amount of self-discharged electricity (FIG. 3) and the calculation method of the capacity that is effectively reduced by the memory effect (FIG. 4 or 5) described in the second or third embodiment. ), The “temperature Tb” is set to “temperature Tp”, the “secondary battery 101” is set to “secondary battery pack 801”, and the “maximum value Tm of the average battery temperature during the self-discharge period based on the temperature Tb”. Deriving the maximum value Tm of the average battery temperature during the self-discharge period based on the temperature Tp ”or the average of the series-connected battery groups during the self-discharge period based on the temperatures Tb1 to Tbn. Deriving the maximum values Tm1 to Tmn of the battery temperature, averaging the maximum values Tm1 to Tmn of the average battery temperature during each self-discharge period, and deriving the maximum value Tm of the average battery temperature during the self-discharge period. , Replaced It is the same as the law, and a description thereof will be omitted.
[0053]
In a battery pack in which secondary battery cells are connected in parallel, a temperature difference may occur between the series-connected battery groups. The value of the remaining capacity of the secondary battery pack 801 differs depending on which secondary battery temperature is measured and the measured value is used in the remaining capacity calculation. According to the third embodiment, the value Tp obtained by averaging the temperatures of all the secondary batteries is used in the calculation of the remaining capacity of the secondary battery pack 801, so that the remaining capacity can be more accurately estimated.
In Example 3, the surface temperatures of all the series-connected battery groups were measured. Instead, the temperature measurement unit 104 may measure each surface temperature of m (2 ≦ m <n) series-connected battery groups that are a part of the n series-connected battery groups of the battery pack. . Preferably, temperature measuring section 104 measures the surface temperature of a plurality (m) of serially connected battery groups physically uniformly distributed to some extent in the battery pack. The temperature averaging unit 804 receives m surface temperatures and calculates an average value Tp.
[0054]
<< Example 4 >>
Fourth Embodiment A remaining capacity calculating device and a remaining capacity calculating method according to a fourth embodiment of the present invention will be described with reference to FIG. FIG. 9 is a configuration diagram of a backup power supply battery management device including the remaining capacity calculation device 900 according to the fourth embodiment of the present invention. The remaining capacity calculation device 900 according to the fourth embodiment is a secondary battery pack that is a secondary battery pack in which a plurality of series-connected battery groups in which one or a plurality of secondary battery cells are connected in series are connected in parallel, as in the third embodiment. The remaining capacity of the 801 is estimated and output. The remaining capacity calculation device 900 according to the fourth embodiment does not include the temperature averaging unit 804 according to the third embodiment, and includes a remaining capacity estimation unit 912 instead of the remaining capacity estimation unit 112 according to the third embodiment. The other configuration is the same as that of the third embodiment, and the description is omitted.
[0055]
The temperature measuring unit 104 has n temperature sensors, each of which measures the surface temperatures Tb1 to Tbn of the series-connected battery groups 1 to n (8011 to 801n), and sends the measured values to the remaining capacity calculation device 900. Send.
[0056]
The remaining capacity estimating unit 912 of the remaining capacity calculating device 900 stores the temperatures Tb1 to Tbn transmitted from the temperature measuring unit 104 as the temperatures of the series connected battery groups 1 to n (8011 to 801n) of the secondary battery pack 801. I do.
[0057]
The remaining capacity estimation unit 912 calculates the remaining capacity of each of the series-connected battery groups 1 to n (8011 to 801n) of the secondary battery pack 801 using the temperatures Tb1 to Tbn. The calculation method is the same as the remaining capacity calculation method described in the second or third embodiment, and a description thereof will not be repeated. The remaining capacity estimating unit 912 calculates the average value of the remaining capacity (assuming the remaining capacity is a percentage value) of each of the series-connected battery groups 1 to n (8011 to 801n), and calculates the average value by two. The remaining capacity of the entire next battery pack 801 is estimated.
[0058]
In Example 4, the surface temperatures of all the series-connected battery groups were measured. Instead, the temperature measurement unit 104 may measure each surface temperature of m (2 ≦ m <n) series-connected battery groups that are a part of the n series-connected battery groups of the battery pack. . Preferably, temperature measuring section 104 measures the surface temperature of a plurality (m) of serially connected battery groups physically uniformly distributed to some extent in the battery pack. The remaining capacity estimating unit 912 calculates the remaining capacity of the m series-connected battery groups, calculates the average value of the remaining capacity (the remaining capacity is a value expressed as a percentage), and calculates the average value by two. The remaining capacity of the entire next battery pack 801 is estimated.
[0059]
【The invention's effect】
Advantageous Effects of Invention According to the present invention, it is possible to realize a remaining capacity calculation device and a remaining capacity calculation method for accurately estimating the remaining capacity of a secondary battery with a small difference between the actually usable capacity of the secondary battery and the estimated remaining capacity. The advantageous effect described above can be obtained.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a backup power supply battery management device including a remaining capacity calculation device according to a first embodiment and a second embodiment of the present invention;
FIG. 2 is a flowchart in a state of charge of the remaining capacity calculation device according to the first and second embodiments of the present invention.
FIG. 3 is a flowchart in a self-discharge state caused by leaving the remaining capacity calculation device according to the first and second embodiments of the present invention.
FIG. 4 is a flowchart illustrating a method for correcting a capacity reduction due to a memory effect on the remaining capacity according to the first embodiment of the present invention;
FIG. 5 is a flowchart showing a method for correcting a capacity reduction due to a memory effect on the remaining capacity according to the second embodiment of the present invention;
FIG. 6 is a conceptual diagram illustrating a memory effect of a secondary battery caused by repetition of charging and self-discharging.
FIG. 7 is a change characteristic diagram of a capacity retention ratio due to self-discharge of a nickel-metal hydride battery.
FIG. 8 is a configuration diagram of a backup power supply battery management device including a remaining capacity calculation device according to a third embodiment of the present invention;
FIG. 9 is a configuration diagram of a backup power supply battery management device including a remaining capacity calculation device according to a fourth embodiment of the present invention.
[Explanation of symbols]
100, 800, 900 remaining capacity calculation device
101 Secondary battery
102 Power supply monitoring control unit
103 Battery monitoring unit
104 Temperature measurement unit
105 Discharger
106 Charger
107 Display
108 Commercial power supply
109 rectifier
110 load
111 I / O section
112,912 Remaining capacity estimation unit
113 Timer section
114 count section
801 Secondary battery pack
8011 Series-connected battery group 1
801n Series-connected battery group n
804 Temperature averaging unit

Claims

A temperature measuring unit for measuring temperature;
Self-discharge electricity quantity derived based on a table or function using the temperature at the time of self-discharge and the elapsed time from the start of self-discharge to the present as parameters, and the effective reduction due to the memory effect caused by repetition of charge and self-discharge A remaining capacity estimating unit for estimating the remaining capacity of the secondary battery based on
An output unit that outputs information on the remaining capacity;
A device for calculating the remaining capacity of a secondary battery, comprising:

The temperature measuring unit further calculates an average value of the temperature for each self-discharge period from the time when charging is completed to the time when the next charge is started, and calculates the maximum value among the average values in each self-discharge period after complete discharge. Extract the maximum self-discharge period average temperature that is
The method according to claim 1, wherein the remaining capacity estimating unit further derives a capacity that is effectively reduced by the memory effect based on a table or a function of a non-linear conversion using the maximum self-discharge period average temperature as a parameter. An apparatus for calculating a remaining capacity of a secondary battery according to claim 1.

After the secondary battery has been completely discharged, the secondary battery further includes a counting unit that counts the number of times the secondary battery changes from a self-discharge state to a charged state or the number of changes from a charged state to a self-discharge state,
The said remaining capacity estimation part further derives the capacity | capacitance which reduces effectively by the said memory effect based on the table or function of the non-linear conversion which uses the said frequency | count as a parameter, The Claim 1 or Claim 2 characterized by the above-mentioned. Rechargeable battery remaining capacity calculation device.

The secondary battery is a secondary battery pack in which a plurality of series-connected battery groups in which one or a plurality of secondary battery cells are connected in series are connected in parallel,
The temperature measurement unit measures the temperature of at least two or more of the series-connected battery groups,
A temperature averaging unit that calculates an average value of the temperatures of the two or more series-connected battery groups,
The remaining capacity estimating unit, as an average value output by the temperature averaging unit as a temperature value, derives at least one of the self-discharged electricity amount and the capacity that is effectively reduced by the memory effect.
The remaining capacity calculating device for a secondary battery according to any one of claims 1 to 3, characterized in that:

The secondary battery is a secondary battery pack in which a plurality of series-connected battery groups in which one or a plurality of secondary battery cells are connected in series are connected in parallel,
The temperature measurement unit measures the temperature of at least two or more of the series-connected battery groups,
The remaining capacity estimation unit estimates the remaining capacity of each series-connected battery group, and estimates the remaining capacity of the entire secondary battery based on the remaining capacity of each series-connected battery group.
The remaining capacity calculating device for a secondary battery according to any one of claims 1 to 3, characterized in that:

The apparatus according to claim 1, wherein the secondary battery is a nickel-metal hydride battery.

A temperature measuring step for measuring the temperature;
Self-discharge electricity quantity derived based on a table or function using the temperature at the time of self-discharge and the elapsed time from the start of self-discharge to the present as parameters, and the effective reduction due to the memory effect caused by repetition of charge and self-discharge Remaining capacity estimation step of estimating the remaining capacity of the secondary battery based on
An output step of outputting information on the remaining capacity;
A method for calculating the remaining capacity of a secondary battery, comprising:

The temperature measuring step further comprises: calculating an average value of the temperature for each self-discharge period from the time of completion of charging to the time of starting the next charging; and Extracting the maximum self-discharge period average temperature that is the value of
The remaining capacity estimation step includes a step of deriving a capacity that is effectively reduced by the memory effect based on a table or a function of a nonlinear conversion using the maximum self-discharge period average temperature as a parameter.
8. The method according to claim 7, wherein the remaining capacity of the secondary battery is calculated.

After the secondary battery is completely discharged, a counting step of counting the number of times the secondary battery changes from a self-discharge state to a charge state or the number of changes from a charge state to a self-discharge state,
Deriving a capacity that is effectively reduced by the memory effect based on a table or function of the non-linear conversion using the number of times as a parameter,
9. The method according to claim 7, further comprising: calculating a remaining capacity of the secondary battery.

The secondary battery is a secondary battery pack in which a plurality of series-connected battery groups in which one or a plurality of secondary battery cells are connected in series are connected in parallel,
The temperature measuring step measures a temperature of at least two or more of the series-connected battery groups,
A temperature averaging step of calculating an average value of the temperatures of the two or more series-connected battery groups,
The remaining capacity estimation step includes a step of deriving at least one of the self-discharged electricity amount and the capacity that is effectively reduced by the memory effect, with the average value output by the temperature averaging unit as a temperature value. ,
The method according to claim 7, further comprising: calculating a remaining capacity of the secondary battery.

The secondary battery is a secondary battery pack in which a plurality of series-connected battery groups in which one or a plurality of secondary battery cells are connected in series are connected in parallel,
The temperature measuring step measures a temperature of at least two or more of the series-connected battery groups,
The remaining capacity estimation step estimates the remaining capacity of each series-connected battery group, and estimates the remaining capacity of the entire secondary battery based on the remaining capacity of each series-connected battery group.
The method for calculating the remaining capacity of a secondary battery according to any one of claims 7 to 9, wherein:

The method according to any one of claims 7 to 11, wherein the secondary battery is a nickel-metal hydride battery.