JP2004025979A - Power supply system for travelling vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply system for a travelling vehicle, accurately detecting charged conditions and proper supplying power required for starting an engine. <P>SOLUTION: The power supply system 50 for the travelling vehicle comprises a lead acid battery detecting part 10 having a microcomputer 10a, a lithium secondary battery control part 20 having a microcomputer 20a, and a vehicle side control part 30 having a microcomputer 30a. The vehicle side control part 30 computes the charged conditions of a lead acid battery 1 and a lithium secondary battery 2 for every preset time from a current flowing in the former, temperature and voltage as well as a current flowing in the latter, temperature and cell voltage. In accordance with the computed charged conditions, the function of a motor generator 3 and the change-over of the switches SW1, SW2, SW3 are controlled. The charged conditions of the lead acid battery 1 and the lithium secondary battery 2 are maintained at 90-60% and at 50-5%, respectively. <P>COPYRIGHT: (C)2004,JPO

Description

【００２０】
モータジェネレータ３は、車両の始動及び車速３０ｋｍ／時程度までの加速走行・低速走行時にはモータとして機能し車両駆動源となる。このときモータジェネレータ３には、鉛蓄電池１及びリチウム二次電池２から電力が供給される。すなわち、モータジェネレータ３は、鉛蓄電池１とリチウム二次電池２との負荷となる。また、モータジェネレータ３は、エンジン駆動中にはエンジンの回転力によりオルタネータ（発電機）として機能する。このとき発電電力により鉛蓄電池１及び／又はリチウム二次電池２は充電可能である。更に、車両制動時には、モータジェネレータ３は高出力のジェネレータとして機能する。このとき回生電力によりリチウム二次電池２は充電可能である。そして、モータジェネレータ３は、切替制御部５によるクラッチ機構等の切替制御により上述した３つの機能のいずれかを有するように切り替えられる。
【００２１】
また、走行車両用電源システム５０には、一端がグランドに接続されたエンジンの点火プラグ、表示パネル、照明類、ワイパ等の補機４の他端が接続可能とされている。補機４には、鉛蓄電池１、リチウム二次電池２及びモータジェネレータ３の少なくとも１つから電力が供給可能である。
【００２２】
図２に示すように、鉛電池検出部１０、リチウム電池制御部２０及び車両側制御部３０のそれぞれのマイコン１０ａ、２０ａ、３０ａは、中央演算処理装置のＣＰＵ、基本制御プログラム及び種々の設定値等を記憶したＲＯＭ、ＣＰＵのワークエリアとして働くと共に種々のデータを一時的に記憶するＲＡＭ及びこれらを接続する内部バスで構成されている。マイコン１０ａ、２０ａ、３０ａは、鉛蓄電池１に接続された図示しない電源供給部からの電源で作動する。
【００２３】
上述したように、鉛蓄電池１は鉛電池検出部１０により電圧等が検出される。すなわち、鉛蓄電池１の負極外部端子は、鉛蓄電池１に流れる電流を検出するホール素子等の電流センサ１２を介してグランドに接続されている。電流センサ１２は、ホール素子に流れる電流に応じて変化するホール電圧により電流を検出することが可能である。鉛蓄電池１の正極外部端子は後述するスイッチＳＷ１の一端に接続されている。また、鉛蓄電池１の正極外部端子及び負極外部端子は、鉛蓄電池１の両端電圧をデジタル値に変換するＡ／Ｄコンバータ１４の入力端子に接続されている。Ａ／Ｄコンバータ１４、電流センサ１２、及び、鉛蓄電池１の温度を検出する温度センサ１１の出力端子は、マイコン１０ａの入力ポートにそれぞれ接続されている。
【００２４】
また、上述したように、リチウム二次電池２はリチウム電池制御部２０により電圧等が検出される。すなわち、リチウム二次電池２の負極外部端子は、リチウム二次電池２に流れる電流を検出するホール素子等の電流センサ２２を介してグランドに接続されている。電流センサ２２は、電流センサ１２と同様に、ホール素子に流れる電流に応じて変化するホール電圧により電流を検出することが可能である。リチウム二次電池２の正極外部端子は後述するスイッチＳＷ２の一端に接続されている。リチウム二次電池２を構成する各単電池の正極端子及び最下位単電池の負極端子は、各単電池の電圧を測定する電圧測定回路２５の入力側端子に接続されている。電圧測定回路２５は、各単電池の電圧を、負極端子を基準とした電圧に変換する差動増幅回路等により構成することができる。電圧測定回路２５の出力側端子は、単電池の電圧をＡ／Ｄ変換するためのマイコン２０ａのＡ／Ｄ入力ポートに接続されている。また、電圧測定回路２５は、マイコン２０ａから電圧測定対象の単電池の指定を受けるためにマイコン２０ａの単電池指定ポートに接続されている。
【００２５】
各単電池の正極端子は、容量調整用のバイパス抵抗Ｒ（各単電池で同一抵抗値）の一端に接続されており、バイパス抵抗Ｒの他端は単電池の容量調整を行うスイッチＳＷの一端に接続されている。スイッチＳＷの他端は各単電池の負極端子に接続されている。また、スイッチＳＷには、制御信号（後述するハイレベル信号、ローレベル信号）を出力するマイコン２０ａの出力ポートが接続されている。従って、マイコン２０ａからの制御信号によりスイッチＳＷがオン状態とされることで、単電池に流れる電流はバイパス抵抗Ｒにより熱消費され各単電池の容量調整が可能である。電流センサ２２、及び、リチウム二次電池２の温度を検出する温度センサ２１の出力端子は、マイコン２０ａの入力ポートにそれぞれ接続されている。
【００２６】
更に、モータジェネレータ３はマイコン３０ａにより切替制御部５を介して切替制御される。モータジェネレータ３の入出力端子の一方には、他端が接続点Ｐに接続されたスイッチＳＷ３の一端に接続されており、入出力端子の他方はグランドに接続されている。なお、スイッチＳＷ３には、制御信号を出力するマイコン３０ａの出力ポートが接続されている。また、マイコン３０ａは、スイッチＳＷ１、ＳＷ２及び後述するスイッチＳＷ４に制御信号を出力する出力ポートを有している。
【００２７】
また、接続点Ｐには、スイッチＳＷ１、ＳＷ２の他端が接続されている。更に、接続点Ｐには、補機４に流れる電流を制限するレギュレータ６を介して補機４の他端が接続されている。レギュレータ６には、スイッチＳＷ４が並列に接続されており、上述したモータジェネレータ３から回生電力が供給されるときのみマイコン３０ａからの制御信号によりスイッチＳＷ４がオフ状態とされる。従って、通常（モータジェネレータ３がジェネレータとして機能するとき以外は）スイッチＳＷ４はオン状態とされ、鉛蓄電池１及び／又はリチウム二次電池２から補機４に電力が供給される。
【００２８】
上述したスイッチＳＷ１、ＳＷ２、ＳＷ３、ＳＷ４、ＳＷには、例えば、スイッチ素子として機能するＦＥＴを用いることができる。すなわち、ＦＥＴのゲートには、マイコンの出力ポートが接続されている。従って、各マイコンの出力ポートからＦＥＴのゲートに微弱なハイレベル信号が入力されるとドレインとソースとの間に電流が流れ、スイッチはオン状態となる。
【００２９】
マイコン１０ａ、２０ａはＩ／Ｏ８を介してマイコン３０ａと通信可能に接続されている。従って、マイコン１０ａ、２０ａは、それぞれ鉛蓄電池１の両端電圧、電流及び温度のデータ、並びに、各単電池の電圧、リチウム二次電池２の電流及び温度のデータを取り込み、取り込んだデータをマイコン３０ａに、例えばシリアル通信により送出することが可能である。
【００３０】
（動作）
まず、鉛蓄電池１及びリチウム二次電池２の充電状態の制御範囲について説明する。
【００３１】
図３に示すように、鉛蓄電池１は、モータジェネレータ３がオルタネータとして機能するときに充電される。すなわち、鉛蓄電池１の充電は、充電状態が６０％未満のときに充電が開始され、充電状態が９０％を超えたときに停止される。従って、鉛蓄電池１の充電状態は６０〜９０％に維持される。リチウム二次電池２は、モータジェネレータ３がオルタネータ又はジェネレータとして機能するときに充電される。すなわち、オルタネータ機能によるリチウム二次電池２の充電は、充電状態が５％未満のときに開始され、充電状態が５０％を超えたときに停止される。従って、リチウム二次電池２の充電状態は５〜５０％に維持される。リチウム二次電池２は、ジェネレータ機能により充電状態が９５％までは充電が許容される。
【００３２】
一方、後述する大電流放電時を除き、リチウム二次電池２の充電状態が３０％未満のときは鉛蓄電池１及びリチウム二次電池２の双方から放電され、リチウム二次電池２の充電状態が３０％以上のときはリチウム二次電池２のみから放電される。なお、図３において、Ｐｂは鉛蓄電池１を、Ｌｉはリチウム二次電池２を表している（後述する表３においても同じ。）。
【００３３】
例えば、図３の（１）Ｌｉ放電状態では、リチウム二次電池２の充電状態が３０％以上のため、リチウム二次電池２のみから放電される。（２）Ｌｉ及びＰｂ放電状態では、リチウム二次電池２の充電状態が３０％未満のため、リチウム二次電池２と鉛蓄電池１との双方から放電される。（３）Ｌｉ充電状態では、リチウム二次電池２の充電状態が５％未満に低下したため、リチウム二次電池２はモータジェネレータ３のオルタネータ機能により充電される。この状態では、鉛蓄電池１の充放電は停止され、補機４にはオルタネータから電力が供給される。リチウム二次電池２の充電状態が５０％を超えると充電は停止される。（４）Ｌｉ放電状態では、リチウム二次電池２のみから放電される。この状態では、上述した（１）Ｌｉ放電状態と同様にリチウム二次電池２の充電状態が３０％以上のため、鉛蓄電池１からは放電されない。（５）回生充電状態では、リチウム二次電池２はモータジェネレータ３のジェネレータ機能により充電される。この状態では、リチウム二次電池２は充電状態９５％までは充電が許容される。（６）Ｌｉ放電状態では、リチウム二次電池２のみから放電される。（７）Ｌｉ及びＰｂ放電状態では、リチウム二次電池２の充電状態が３０％未満のため、リチウム二次電池２と鉛蓄電池１との双方から放電される。（８）Ｐｂ充電状態では、鉛蓄電池１の充電状態が６０％未満に低下したため、鉛蓄電池１はオルタネータ機能により充電される。この状態では、リチウム二次電池２の充放電は停止され、補機４にはオルタネータから電力が供給される。鉛蓄電池１の充電状態が９０％を超えると充電は停止される。
【００３４】
次に、鉛蓄電池１及びリチウム二次電池２の充電状態の演算について説明する。
【００３５】
マイコン３０ａは、車両駐車中（車両のイグニッションスイッチがオン位置に位置する前）に、所定時間（例えば、６時間）毎に１回の割合で図示しない電源供給部からマイコン１０ａに電源を供給させる。マイコン１０ａは、鉛蓄電池１の開路電圧ＯＣＶ及び温度のデータを検出し、Ｉ／Ｏ８を介してマイコン３０ａに送出する。マイコン３０ａは、マイコン１０ａからのデータ受信後に、マイコン１０ａへの電源供給を停止させ、マイコン３０ａのＲＯＭに予め記憶されており初期設定においてＲＡＭに展開されている鉛蓄電池１の電池状態マップにより、鉛蓄電池１の残存容量Ｑｒｅｓ及び充電状態ＳＯＣを演算しＲＡＭに格納する。
【００３６】
この演算方法について詳述すると、表２に示すように、電池状態マップは、例えば、開路電圧ＯＣＶ、残存容量Ｑｒｅｓ及び充電状態ＳＯＣ等が対応した状態でＲＡＭに展開されている。表２は、温度２５°Ｃ、電流２５０Ａにおける一例を示したものである。
【００３７】
【表２】

【００３８】
マイコン３０ａは、まず、マイコン１０ａから受信した温度における鉛蓄電池１の開路電圧を、２５°Ｃにおける開路電圧に温度補正する。図４に示すように、マイコン３０ａのＲＡＭには、例えば、２５°Ｃにおける開路電圧に対する温度−開路電圧補正マップが展開されている。マイコン３０ａは、受信した開路電圧に、補間法を利用して求めた開路電圧補正値を加算して、２５°Ｃにおける開路電圧を求める。次に、マイコン３０ａは、２５°Ｃにおける開路電圧から表２の電池状態マップにより補間法を利用して鉛蓄電池１の残存容量Ｑｒｅｓ及び充電状態ＳＯＣを演算してＲＡＭに格納する。
【００３９】
マイコン３０ａは、車両のイグニッションスイッチがオン位置に位置すると、図示しない電源供給部からマイコン１０ａに電源を供給させる。これにより、マイコン１０ａは、鉛蓄電池１の温度を検出すると共に鉛蓄電池１の電流を検出し検出した電流を積算し、所定時間（例えば、１０秒）毎に、積算電気量（積算した電流の量）及び鉛蓄電池１の温度のデータをマイコン３０ａに送出する。マイコン３０ａは、ＲＡＭに格納した鉛蓄電池１の残存容量Ｑｒｅｓにマイコン１０ａから受信した積算電気量を順次加（減）算することで現在の鉛蓄電池１の残存容量を算出して、表２の電池状態マップから現在の残存容量に対応する現在の充電状態ＳＯＣを算出する。
【００４０】
一方、マイコン３０ａは、原則としてマイコン１０ａの場合と同様に、マイコン３０ａのＲＡＭに展開されているリチウム二次電池２の電池状態マップ及び図４に示したと同様の温度−開路電圧補正マップにより、リチウム二次電池２の残存容量Ｑｒｅｓ及び充電状態ＳＯＣを算出する。
【００４１】
マイコン２０ａは各単電池毎に開路電圧を検出する点でマイコン１０ａによる鉛蓄電池１の開路電圧の検出とは異なっている。すなわち、マイコン２０ａは、単電池指定ポートから電圧測定回路２５に測定対象の単電池を指定することで、Ａ／Ｄ入力ポートを介して電圧測定回路２５から測定対象の単電池電圧（開路電圧）を取り込む。マイコン３０ａは、マイコン２０ａから温度及び各単電池電圧を受信し、各単電池電圧を２５°Ｃにおける電圧に温度補正し、図５に示すように、温度−開路電圧補正マップ（又は関係式）により各単電池の充電状態ＳＯＣを算出する。なお、非晶質炭素を負極活物質に用いた単電池では、開路電圧をｙ、充電状態をｘとしたときに、両者には、ｙ＝−５Ｅ−０．７ｘ^３＋６Ｅ−０．６ｘ^２＋０．０１６８ｘ＋２．８９７１（収束半径Ｒ^２＝０．９９９４）の関係がある。また、マイコン３０ａは、全単電池の平均充電状態をリチウム二次電池２の充電状態ＳＯＣとして算出する。
【００４２】
更に、マイコン３０ａは、各単電池について、（当該単電池の充電状態ＳＯＣ−全単電池の平均充電状態）が５ポイントを超える（容量調整の対象となる）単電池が存在するか否かを判断し、肯定判断のときは、当該単電池についてのみバイパス抵抗Ｒの抵抗値に依存する容量調整時間ｔをそれぞれ算出し、容量調整が未了であることを示す状態フラグを０から１に変更する。なお、このような容量調整時間ｔの算出については、例えば、特開２０００−３１２４４３号公報に開示されている。
【００４３】
次に、鉛蓄電池１及びリチウム二次電池２の充放電制御について、マイコン３０ａを主体として説明する。
【００４４】
下表３に示すように、マイコン３０ａは、車両状態及び充電状態に基づいて、スイッチＳＷ１、ＳＷ２、ＳＷ３及びモータジェネレータ３の機能を切り替えることにより、鉛蓄電池１及びリチウム二次電池２の充放電を制御する。
【００４５】
１．車両駐車中における充放電制御
＜イグニッションスイッチオフ位置＞
マイコン３０ａは、イグニッションスイッチがオフ位置に位置した場合に、スイッチＳＷ１、ＳＷ２、ＳＷ３をオフ状態とする。これにより、鉛蓄電池１及びリチウム二次電池２はマイコン３０ａに供給される微小な電力を除き、充放電休止状態となる（下表３（４）参照）。なお、マイコン３０ａは、上述したように鉛蓄電池１及びリチウム二次電池２の充電状態を演算している。
【００４６】
＜イグニッションスイッチオン位置＞
マイコン３０ａは、イグニッションスイッチがオン位置に位置した場合に、ＲＡＭに格納した鉛蓄電池１の充電状態が６０％未満かつリチウム二次電池２の充電状態が５％未満か否かを判断する。肯定判断のときは、充電が必要な旨を運転席の表示パネルに表示させ、否定判断のときは、スイッチＳＷ２をオン状態（スイッチＳＷ１、ＳＷ３：オフ状態）とする。これにより、リチウム二次電池２は補機４への電力供給で放電状態となる。
【００４７】
【表３】

【００４８】
＜イグニッションスイッチスタート位置＞
マイコン３０ａは、イグニッションスイッチがスタート位置に位置した場合に、上述した肯定判断のとき（鉛蓄電池１の充電状態が６０％未満かつリチウム二次電池２の充電状態が５％未満のとき）は、モータジェネレータ３がモータとして機能するように切替制御部５を切替制御させると共に、スイッチＳＷ１、ＳＷ２、ＳＷ３をオン状態としてエンジンの点火プラグに鉛蓄電池１及びリチウム二次電池２の双方から大電流を供給する。マイコン３０ａは、エンジンが始動すると、モータジェネレータ３をオルタネータに切り替えると共に、スイッチＳＷ１をオフ状態とする（スイッチＳＷ２、ＳＷ３：オン状態）。これにより、リチウム二次電池２は充電状態が５０％となるまで充電される（詳細後述）。一方、マイコン３０ａは、イグニッションスイッチがスタート位置に位置した場合に、上述した否定判断のとき（鉛蓄電池１の充電状態が６０％以上又はリチウム二次電池２の充電状態が５％以上のとき）は、モータジェネレータ３をモータとして機能させると共に、スイッチＳＷ１、ＳＷ３をオン状態（スイッチＳＷ２：オン状態）とする。これにより、モータジェネレータ３には、鉛蓄電池１及びリチウム二次電池２の双方から大電流が供給される。
【００４９】
２．車両走行中における充放電制御
＜モータ駆動＞
マイコン３０ａは、車両をエンジンではなくモータで始動した後に、車速ｖの変化から車両が加速状態と判断した場合（ｄｖ／ｄｔ＞＞０）に、スイッチＳＷ１、ＳＷ２、ＳＷ３をオン状態とする。これにより、モータ及び補機４には、鉛蓄電池１及びリチウム二次電池２の双方から大電流が供給される（表３（１）参照）。一方、マイコン３０ａは、加速状態ではないと判断した場合（ｄｖ／ｄｔがほぼ０）に、リチウム二次電池２の充電状態が３０％以上か否かを判断し、肯定判断のときは、スイッチＳＷ１をオフ状態、スイッチＳＷ２、ＳＷ３をオン状態とし、否定判断のときは、スイッチＳＷ１、ＳＷ２、ＳＷ３をオン状態とする。これにより、リチウム二次電池２の充電状態が３０％以上の状態ではリチウム二次電池２のみから、充電状態が３０％未満の状態では鉛蓄電池１及びリチウム二次電池２の双方からの電力がモータ及び補機４に供給される（表３（２）参照）。
【００５０】
また、マイコン３０ａは、（１）加速走行状態、（２）低速走行状態、又はリチウム二次電池２の充電状態が５％未満のためにエンジンを始動させた状態において、鉛蓄電池１の充電状態が６０％未満又はリチウム二次電池２の充電状態が５％未満と判断したときは、モータの回転力によりエンジンを始動させ、モータジェネレータ３をオルタネータに切り替えると共に、スイッチＳＷ１又はスイッチＳＷ２をオン状態、スイッチＳＷ３をオン状態とする。これにより、鉛蓄電池１又はリチウム二次電池２は充電される（詳細後述）。マイコン３０ａは、車速が例えば、３０ｋｍ／時以上のときは、エンジンを始動させ、スイッチＳＷ２をオン状態、スイッチＳＷ３をオフ状態とする。これにより、車両はエンジンにより駆動され、補機４にはリチウム二次電池２からの電力が供給される。
【００５１】
＜エンジン駆動＞
マイコン３０ａは、エンジン駆動による走行中の場合に、リチウム二次電池２の充電状態が３０％以上か否かを判断し、肯定判断のときは、スイッチＳＷ１をオフ状態、スイッチＳＷ２をオン状態とし、否定判断のときは、スイッチＳＷ１、ＳＷ２をオン状態とする。これにより、リチウム二次電池２の充電状態が３０％以上の状態ではリチウム二次電池２のみから、充電状態が３０％未満の状態では鉛蓄電池１及びリチウム二次電池２の双方からの電力が補機４に供給される（表３（３）参照）。また、マイコン３０ａは、鉛蓄電池１の充電状態が６０％未満又はリチウム二次電池２の充電状態が５％未満と判断したときは、モータジェネレータ３をオルタネータに切り替えると共に、スイッチＳＷ１又はスイッチＳＷ２をオン状態、スイッチＳＷ３をオン状態とする。これにより、鉛蓄電池１又はリチウム二次電池２は充電される（詳細後述）。
【００５２】
＜アイドルストップ＞
マイコン３０ａは、走行中の一時的な停車のときにエンジン駆動を停止した場合（アイドルストップ状態）に、上述したエンジン走行中と同様にリチウム二次電池２の充電状態が３０％以上か否かの判断に応じてスイッチＳＷ１、ＳＷ２、ＳＷ３を制御し、補機４に電力を供給する。また、アイドルストップ後に車両を再起動する場合は、上述した（１）加速走行状態となる。
【００５３】
＜オルタネータ機能による充電＞
マイコン３０ａは、エンジン駆動中、上述したようにリチウム二次電池２の充電状態が５％未満と判断したときは、モータジェネレータ３をオルタネータに切り替えると共に、スイッチＳＷ１をオフ状態、スイッチＳＷ２、ＳＷ３をオン状態とする。これにより、リチウム二次電池２はオルタネータから供給される電力により充電される（表３（５）参照）。また、マイコン３０ａは上述した状態フラグを確認し、単電池の容量調整が未了のときは、容量調整対象の単電池のＩＤ及び容量調整時間ｔをマイコン２０ａに通知する。これにより、マイコン２０ａは、容量調整時間ｔの間、マイコン３０ａから通知された単電池のスイッチＳＷをオン状態とすることで容量調整対象の単電池の容量が調整される。マイコン３０ａは、リチウム二次電池２の充電状態が５０％を超えたときは、スイッチＳＷ３をオフ状態（スイッチＳＷ１：オフ状態、スイッチＳＷ２：オン状態）とし、状態フラグを１から０に変更する。これにより、リチウム二次電池２への充電は停止され、全単電池の充電状態がほぼ均一の５０％となり、リチウム二次電池２から補機４への電力供給が開始される。なお、容量調整は、上述した開路電圧から充電状態を演算した後の初回のリチウム二次電池２の充電中に１回のみ実行される。
【００５４】
また、マイコン３０ａは、上述したように鉛蓄電池１の充電状態が６０％未満と判断したときは、モータジェネレータ３をオルタネータに切り替えると共に、スイッチＳＷ１、ＳＷ３をオン状態、スイッチＳＷ２をオフ状態とする。これにより、鉛蓄電池１はオルタネータから供給される電力により充電される。マイコン３０ａは、鉛蓄電池１の充電状態が９０％を超えたときは、スイッチＳＷ１、ＳＷ３をオフ状態、スイッチＳＷ２をオン状態とする。これにより、鉛蓄電池１の充電は停止され、リチウム二次電池２から補機４への電力供給が開始される。
【００５５】
＜回生電力による充電＞
マイコン３０ａは、車両が制動状態の場合（ｄｖ／ｄｔ＜＜０）に、リチウム二次電池２の充電状態が７５％未満か否かを判断する。肯定判断のときは、モータジェネレータ３をジェネレータに切り替えると共に、スイッチＳＷ１をオフ状態、スイッチＳＷ２、ＳＷ３をオン状態とし、否定判断のときは、スイッチＳＷ１、ＳＷ３をオフ状態、スイッチＳＷ２をオン状態として補機４にリチウム二次電池２から電力を供給する。これにより、リチウム二次電池２の充電状態が７５％未満の状態では、リチウム二次電池２は回生電力による充電がなされ、充電状態が７５％以上の状態では回生電力の受け入れ開始はなされない（表３（６）参照）。マイコン３０ａは、回生電力による充電でリチウム二次電池２の充電状態が９５％を超えたときは、スイッチＳＷ３をオフ状態とする（スイッチＳＷ１：オフ状態、スイッチＳＷ２：オン状態）。これにより、リチウム二次電池２への回生電力による充電は停止され、リチウム二次電池２から補機４への電力供給が開始される。なお、イグニッションスイッチがオフ位置に位置したときは、上述した（４）駐車状態となる。
【００５６】
（作用）
次に、本実施形態の走行車両用電源システム５０の作用等について説明する。
【００５７】
本実施形態の走行車両用電源システム５０では、マイコン３０ａが、車両駐車中にマイコン１０ａ、２０ａから受信した鉛蓄電池１及びリチウム二次電池２の各単電池の開路電圧ＯＣＶ及び温度データにより、温度補正後の開路電圧で鉛蓄電池１及び各単電池の残存容量Ｑｒｅｓを算出しておき、その後、算出した残存容量Ｑｒｅｓに積算電気量を加減算することで鉛蓄電池１及びリチウム二次電池２の現在の充電状態ＳＯＣを演算する。このため、温度、開路電圧、電流データから所定時間毎に充電状態の演算なされるので、鉛蓄電池１及びリチウム二次電池２の充電状態を高精度に把握することができる。
【００５８】
また、マイコン３０ａは、鉛蓄電池１及び／又はリチウム二次電池２の充電状態が所定の下限値未満のときに、モータジェネレータ３の機能及びスイッチＳＷ１〜ＳＷ３を制御して、鉛蓄電池１及び／又はリチウム二次電池２の充電を開始し、充電状態が所定の上限値を越えたときに充電を停止する。このため、鉛蓄電池１及びリチウム二次電池２の充電状態はそれぞれ所定範囲に維持される。従って、本実施形態の走行車両用電源システム５０では、鉛蓄電池１及びリチウム二次電池２が過放電状態及び過充電状態となることを防止することができると共に、鉛蓄電池１及び／又はリチウム二次電池２からエンジン始動に必要な電力が適正に供給されるので、アイドルストップ後のエンジンスタートを確実に行うことができる。
【００５９】
更に、本実施形態の走行車両用電源システム５０では、回生電力によるリチウム二次電池２の充電は充電状態９５％までは許容されるので、リチウム二次電池２は回生電力を十分に受け入れることができる。また、リチウム二次電池２の充電状態が７５％以上のときは、回生電力の受け入れ開始はなされないため、リチウム二次電池２が過充電状態となることを防止することができる。逆に、リチウム二次電池２は充電状態が５％未満となると、５０％となるまでモータジェネレータ３のオルタネータ機能により充電されるので、過放電状態となることも防止することができる。
【００６０】
また更に、本実施形態の走行車両用電源システム５０では、マイコン２０ａが、モータジェネレータ３のオルタネータ機能によるリチウム二次電池２の充電中に容量調整の対象となる単電池に並列接続されたスイッチＳＷを容量調整時間ｔの間オン状態として充電電流をバイパス抵抗Ｒに熱消費させる。このため、各単電池の充電状態のバラツキが均一化されるので、容量の異なる単電池が他の単電池の負荷となるで生じるリチウム二次電池２の寿命の低下を防止することができる。
【００６１】
更にまた、本実施形態の走行車両用電源システム５０では、マイコン３０ａが、リチウム二次電池２の充電状態が所定値以上のときは、リチウム二次電池２のみから放電するようにスイッチＳＷ１〜ＳＷ３を制御する。このため、リチウム二次電池２からの放電が優先されることから、電力受入性に優れるリチウム二次電池２の利用効率を高めることができ、ひいては、鉛蓄電池１及びリチウム二次電池２全体の効率を向上させることができる。
【００６２】
また、マイコン３０ａは、リチウム二次電池２の充電状態が所定値未満のとき又は車両が加速走行状態のときに、鉛蓄電池１とリチウム二次電池２との双方から放電させるようにスイッチＳＷ１〜ＳＷ３を制御することで、容量の大きい鉛蓄電池１と併用して大電流の電力を適正に供給することができ、補機４の消費電流が大きくても車両をモータ駆動で確実に始動させることができる。このため、アイドルストップ後においても、大電流の電力が適正に供給されるので、車両の始動を確実に行うことができる。従って、特に混雑した市街地では、エンジンの使用が低減され、環境問題に対処することが可能となる。
【００６３】
なお、本実施形態では、鉛蓄電池１及びリチウム二次電池２に流れる電流をマイコン１０ａ、２０ａでそれぞれ検出しマイコン３０ａに通信する例を示したが、マイコン３０ａで電流を検出するようにしてもよい。このようにすれば、マイコン３０ａは通信することなく充電状態の演算が可能となるので、充電状態の演算及び充電制御を一層速やかに行うことができる。また、本実施形態では、マイコン１０ａは鉛蓄電池１の電圧をＡ／Ｄコンバータ１４を介して検出する例を示したが、Ａ／Ｄ変換をマイコン１０ａで行うようにしてもよい。更に、本実施形態では、スイッチＳＷ１〜ＳＷ３をマイコン３０ａで制御する例を示したが、例えば、スイッチＳＷ２はマイコン２０ａで制御するようにしてもよい。また更に、本実施形態では、マイコン３０ａ以外に、マイコン１０ａ、２０ａを有する例を示したが、マイコン３０ａ単独又はマイコン２０ａ、３０ａで電圧等の検出、充電状態の演算及び充電制御を行うようにしてもよい。このようにすれば、通信時間を短縮して充電状態の演算及び充電制御をより速やかに行うことができる。
【００６４】
また、本実施形態では、鉛蓄電池１の充電状態を６０〜９０％の範囲、リチウム二次電池２の充電状態を５〜５０％の範囲となるようにそれぞれ充電制御する例を示したが、本発明はこれに限定されるものではなく、例えば、車両始動に必要な電力量やモータジェネレータ３から回生される電力量により所定範囲を設定してもよい。
【００６５】
更に、本実施形態では、モータ、オルタネータ及びジェネレータとして機能するモータジェネレータ３を例示したが、エンジン駆動中に鉛蓄電池１及び／又はリチウム二次電池２を充電するためのオルタネータをモータジェネレータから分離して構成するようにしてもよい。
【００６６】
また更に、本実施形態では、リチウム二次電池２がオルタネータからの電力で充電されるときに単電池の容量調整を行う例を示したが、本発明はこれに限定されるものではなく、リチウム二次電池２の放電状態や休止状態において容量調整を行うようにしてもよい。
【００６７】
更にまた、本実施形態では、大電流を要する加速走行時には鉛蓄電池１及びリチウム二次電池２の双方から、又は、低速走行時にはリチウム二次電池２の充電状態が３０％未満の場合を除いてリチウム二次電池２のみからモータに電力を供給させる例を示したが、エンジンを始動させるまで鉛蓄電池１及びリチウム二次電池２の双方から電力を供給させるようにしてもよい。このようにすれば、スイッチＳＷ１〜ＳＷ３のオン・オフ制御を簡素化することができる。
【００６８】
また、本実施形態では、鉛蓄電池１をオルタネータからの電力のみで充電する例を示したが、鉛蓄電池１とリチウム二次電池２とは並列接続可能なため、例えば、駐車状態において、リチウム二次電池の充電状態が２０％以上のときにスイッチＳＷ１、ＳＷ２をオン状態とし、リチウム二次電池２から鉛蓄電池１に電力を供給して鉛蓄電池１を充電するようにしてもよい。
【００６９】
更に、本実施形態では、開路電圧を温度補正して充電状態を求める例を示したが、温度−充電状態補正マップを予め作成しておき充電状態を温度補正するようにしてもよい。
【００７０】
また更に、本実施形態では、水溶液系二次電池群として３６Ｖ系の鉛蓄電池１、非水系二次電池群として３６Ｖ系のリチウム二次電池２を例示したが、本発明はこれに限定されるものではなく、１２Ｖ系鉛蓄電池や１２Ｖ系リチウム二次電池又はニッケル−水素電池等を用いる場合にも適用可能である。
【００７１】
【発明の効果】
以上説明したように、本発明によれば、充電状態演算部により、電流及び電圧から電池群それぞれの充電状態が演算されるので、充電状態を精度よく検出することができると共に、充電状態制御部により、それぞれの電池群が所定範囲内に充電制御されるので、エンジン始動に必要な電力を適正に供給することができ、ＩＳＳ時にアイドルストップ後のエンジンを確実に再始動することができる、という効果を得ることができる。
【図面の簡単な説明】
【図１】本発明が適用可能な実施形態の走行車両用電源システムの概略ブロック図である。
【図２】実施形態の走行車両用電源システムのブロック回路図である。
【図３】鉛蓄電池及びリチウム二次電池の充電状態の制御範囲を模式的に示す説明図である。
【図４】鉛蓄電池の温度と開路電圧補正値との対応を模式的に示すグラフである。
【図５】リチウムイオン二次電池の充電状態と開路電圧との対応を模式的に示すグラフである。
【符号の説明】
１　鉛蓄電池（水溶液系二次電池群）
２　リチウム二次電池（非水系二次電池群）
１０　鉛電池検出部（充電状態演算部の一部）
２０　リチウム電池制御部（充電状態演算部の一部）
３０　車両側制御部（充電状態演算部の一部、充電状態制御部の一部）
５０　走行車両用電源システム
Ｒ　バイパス抵抗（バイパス開路の一部）
ＳＷ　スイッチ（バイパス開路の一部）
ＳＷ１　スイッチ（充電を開始する開路の一部、充電を停止する開路の一部）
ＳＷ２　スイッチ（充電を開始する開路の一部、充電を停止する開路の一部）
ＳＷ３　スイッチ（充電を開始する開路の一部、充電を停止する開路の一部）[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a power supply system for a traveling vehicle, and in particular, an aqueous secondary battery group connected to a plurality of aqueous secondary batteries and a non-aqueous secondary battery group connected to a plurality of non-aqueous secondary batteries are connected in parallel. A possible power supply system for a traveling vehicle.
[0002]
[Prior art]
Conventionally, a power supply system (14V system) equipped with a 12V lead storage battery has been used in automobiles. In this 14V system, a current is supplied (discharged) to a starting device (starter motor) for starting an automobile engine from a 12V lead storage battery, and after the engine is started, a generator operated by the rotational force of the running engine The current is constantly supplied (charged) to the 12V lead storage battery from the above. However, the energy at the time of deceleration (at the time of braking) of the automobile has been consumed as heat.
[0003]
By the way, in recent years, measures to reduce exhaust gas and use energy efficiently by idle stop / start (hereinafter abbreviated as ISS) have been promoted, and a new power supply system equipped with a 36V lead storage battery instead of a 12V lead storage battery has been developed. (42V system) has been proposed. In this 42V system, it is possible to use a high-power motor generator as a starting device for starting an automobile engine, and convert the energy that was conventionally consumed as heat during deceleration of the automobile into electric energy by the motor generator. Then, the battery is supplied (charged) as regenerative energy to a 36V lead storage battery. As a result, the 36V lead storage battery is charged with electric energy using the rotational force of the engine when the vehicle is running and the rotational force of the wheels during deceleration. For this reason, in the 42V system, the energy efficiency is improved, and the fuel efficiency of the automobile can be improved.
[0004]
However, the motor generator used in the 42V system has a high output of 3 to 4 kW, and the current value during regeneration reaches 40 to 80 A (corresponding to 2 to 4 CA). It is difficult to accept. In a lead storage battery, when the charging rate becomes a current value of 1 C or more, a water decomposition reaction, which is a side reaction at the time of charging, is promoted, and the charging efficiency is reduced, thereby adversely affecting the battery life. In order to solve this problem, there has been a proposal to control charging by constant voltage charging in a region where side reactions do not occur, but since the voltage reaches the constant voltage region immediately, loss of regenerative power increases. Would. Therefore, a power supply system for a traveling vehicle has been devised in which an aqueous secondary battery group having a large capacity and a non-aqueous secondary battery group having a high regenerative power acceptability are connected in parallel.
[0005]
[Problems to be solved by the invention]
However, in the traveling vehicle power supply system, it is difficult to receive regenerative power when the state of charge of the non-aqueous secondary battery group is high in order to avoid overcharging. Further, when the charged state of the aqueous secondary battery and the non-aqueous secondary battery during the ISS is low, the power required for starting the engine cannot be supplied, so that the engine cannot be started after the idle stop. For this reason, it is necessary to accurately detect the state of charge of the aqueous secondary battery and the non-aqueous secondary battery.
[0006]
The present invention has been made in view of the above circumstances, and has as its object to provide a power supply system for a traveling vehicle that can accurately detect a state of charge and appropriately supply power required for starting an engine.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides an aqueous secondary battery group connected to a plurality of aqueous secondary batteries and a non-aqueous secondary battery group connected to a plurality of non-aqueous secondary batteries can be connected in parallel. A power supply system for a traveling vehicle, comprising measuring current and voltage flowing through the aqueous secondary battery group and the non-aqueous secondary battery group, and measuring the aqueous secondary battery group and the aqueous battery from the measured current and voltage. A charge state calculation unit that calculates each charge state of the non-aqueous secondary battery group, and the aqueous solution-based secondary battery group and the non-aqueous secondary battery group based on the charge state calculated by the charge state calculation unit A charge state control unit that performs charge control so as to maintain the charge state in each of the predetermined ranges.
[0008]
In the present invention, the current and voltage flowing through the aqueous secondary battery group and the non-aqueous secondary battery group are measured by the charge state calculation unit, and the aqueous secondary battery group and the non-aqueous secondary battery group are measured based on the measured current and voltage. The state of charge of each of the secondary battery groups is calculated, and the state of charge of the aqueous secondary battery group and the nonaqueous secondary battery group is calculated by the charge state control unit based on the state of charge calculated by the charge state calculation unit. The charging is controlled so as to be maintained within a predetermined range. According to the present invention, since the state of charge of each battery group is calculated from the current and the voltage by the state of charge calculation unit, the state of charge can be accurately detected, and the state of charge of each battery group can be determined by the state of charge control unit. Is controlled within a predetermined range, so that electric power required for starting the engine can be supplied appropriately. Therefore, it is possible to reliably restart the engine after the idle stop at the time of the ISS.
[0009]
In the present invention, the aqueous secondary battery group may be configured by a lead storage battery connected in series, and the non-aqueous secondary battery group may be configured by a lithium secondary battery connected in series. At this time, the lead storage battery is preferably a control valve type lead storage battery, and the lithium secondary battery is preferably a lithium ion secondary battery.
[0010]
In addition, the charge state control unit, when the individual charge state of the non-aqueous secondary battery calculated by the charge state calculation unit is higher than the average charge state of the non-aqueous secondary battery, a non-aqueous secondary battery with a high charge state If it is configured to have a bypass circuit that bypasses the charging current flowing through the battery, it is possible to prevent the life of the non-aqueous secondary battery from being shortened by equalizing the variation in the capacity of the plurality of non-aqueous secondary batteries. . Furthermore, if the state-of-charge control unit has a circuit that starts charging the aqueous secondary battery group and the non-aqueous secondary battery group when the state of charge is lower than the lower limit of the predetermined range, the state of charge is within the predetermined range. By starting charging when lower than the lower limit of the above, it is possible to prevent an overdischarge state, and when higher than the upper limit of the predetermined range, the aqueous secondary battery group and the non-aqueous secondary battery group If the circuit for stopping charging is provided, the charging is stopped when the charge is higher than the upper limit value of the predetermined range, thereby preventing an overcharged state.
[0011]
Further, if the charge state control unit controls the non-aqueous secondary battery group to supply power to the discharge load when the charge state of the non-aqueous secondary battery group is equal to or higher than a predetermined charge state within a predetermined range, the power The use efficiency of the non-aqueous secondary battery group, which is excellent in acceptability, can be improved, and the aqueous solution can be used when the state of charge of the non-aqueous secondary battery group is lower than a predetermined state of charge or when power is supplied to the vehicle driving motor. If control is performed to supply power to the discharge load from both the secondary battery group and the non-aqueous secondary battery group, the non-aqueous secondary battery group is prevented from being in an over-discharge state, and the vehicle driving motor is controlled. A large current required for starting (starting the engine) can be supplied.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a power supply system for a traveling vehicle to which the present invention is applied will be described with reference to the drawings.
[0013]
(Constitution)
As shown in FIG. 1, the power supply system 50 for a traveling vehicle includes a lead storage battery 1 as an aqueous secondary battery group, a lithium secondary battery 2 as a non-aqueous secondary battery group, and a microcomputer 10a to be described later. 1, a lead battery detector 10 for detecting voltage, current and temperature, and a voltage of a lithium ion secondary battery (hereinafter referred to as a unit cell) constituting a lithium secondary battery 2 having a microcomputer 20a to be described later. A lithium battery control unit 20 that detects the current and temperature of the battery 2 and adjusts the capacity of each cell; and a lead storage battery having a microcomputer 30a to be described later and communicating with the lead battery detection unit 10 and the lithium battery control unit 20. 1 and a vehicle-side control unit 30 that calculates the state of charge of each cell and controls the entire vehicle. The lead storage battery 1 and the lithium secondary battery 2 can be connected in parallel by a switch described later.
[0014]
The lead storage battery 1 uses a monoblock battery case in which a battery case defines 18 cell chambers by partition walls that partition the inside of the battery vertically and horizontally. A sensor insertion hole is formed in a central partition wall of the monoblock battery case. A temperature sensor such as a thermistor for detecting the temperature of the lead storage battery 1 is inserted into the sensor insertion hole, and the temperature sensor is fixed in the sensor insertion hole with an adhesive.
[0015]
In each cell chamber of the lead-acid battery 1, a group of electrode plates in which a plurality of positive electrode plates and negative electrode plates are laminated via a glass fiber separator is accommodated one by one, and diluted sulfuric acid as an electrolytic solution is injected. I have. Lead dioxide can be used for the positive electrode active material of the lead storage battery 1 and spongy lead can be used for the negative electrode active material. Each cell chamber is sealed with a lid that integrally covers the opening of the monoblock battery case, and a control valve is provided above each cell chamber to be sealed. Each cell chamber is connected in series by a conductive connecting member. At the upper diagonal position of the lead storage battery 1, a positive external terminal and a negative external terminal serving as external output terminals are provided upright. The nominal voltage of each cell is 2 V, and the capacity of the lead storage battery 1 is 18 Ah. Therefore, the lead storage battery 1 is a 36V control valve type lead storage battery. In addition, the negative electrode external terminal of the lead storage battery 1 is connected to the ground.
[0016]
On the other hand, the lithium secondary battery 2 is configured to have a positive electrode external terminal on the highest potential side and a negative electrode external terminal on the lowest potential side by connecting eleven cells in series. These eleven unit cells are arranged in four rows, three, four, and three rows and one row, respectively, in the horizontal direction. A temperature sensor, such as a thermistor, for detecting the temperature of the lithium secondary battery 2 is fixed to the surface of the battery can of one of the 11 single cells located at the center. The negative electrode external terminal of the lithium secondary battery 2 is connected to the ground.
[0017]
The unit cell has a wound electrode body in which a positive electrode in which a positive electrode active material is applied to an aluminum foil and a negative electrode in which a negative electrode active material is applied to a copper foil are wound via a microporous separator. The electrode body is immersed in a non-aqueous electrolyte and accommodated in a cylindrical battery can. Each battery can is sealed with a sealing body also serving as a positive electrode terminal. A manganese oxide containing lithium can be used as the positive electrode active material of the unit cell, and carbon powder can be used as the negative electrode active material. The nominal voltage of the cell is 3.6 V and the capacity is 3.5 Ah.
[0018]
The other end of the motor generator 3 having one end connected to the ground is connectable to the traveling vehicle power supply system 50. As shown in Table 1 below, the motor generator 3 has three functions of a motor that drives the vehicle and starts the engine, an alternator that generates electric power by the rotational force of the engine, and a generator that converts regenerative energy during vehicle braking into electric energy. Have.
[0019]
[Table 1]

[0020]
The motor generator 3 functions as a motor and serves as a vehicle drive source when the vehicle is started and when the vehicle is running at an accelerated or low speed up to a vehicle speed of about 30 km / hour. At this time, electric power is supplied to motor generator 3 from lead storage battery 1 and lithium secondary battery 2. That is, motor generator 3 becomes a load on lead storage battery 1 and lithium secondary battery 2. Further, the motor generator 3 functions as an alternator (generator) by the rotational force of the engine while the engine is running. At this time, the lead storage battery 1 and / or the lithium secondary battery 2 can be charged by the generated power. Further, during vehicle braking, the motor generator 3 functions as a high-output generator. At this time, the lithium secondary battery 2 can be charged by the regenerative electric power. Then, the motor generator 3 is switched to have any of the three functions described above by switching control of the clutch mechanism and the like by the switching control unit 5.
[0021]
The other end of the auxiliary machine 4 such as an engine spark plug, a display panel, lights, a wiper or the like, one end of which is connected to the ground, can be connected to the traveling vehicle power supply system 50. The auxiliary machine 4 can be supplied with electric power from at least one of the lead storage battery 1, the lithium secondary battery 2, and the motor generator 3.
[0022]
As shown in FIG. 2, the microcomputers 10a, 20a, 30a of the lead battery detection unit 10, the lithium battery control unit 20, and the vehicle-side control unit 30 include a CPU of the central processing unit, a basic control program, and various set values. And a RAM that serves as a work area for the CPU and temporarily stores various data, and an internal bus that connects them. The microcomputers 10a, 20a, and 30a operate with power from a power supply unit (not shown) connected to the lead storage battery 1.
[0023]
As described above, the voltage and the like of the lead storage battery 1 are detected by the lead battery detection unit 10. That is, the negative electrode external terminal of the lead storage battery 1 is connected to the ground via the current sensor 12 such as a Hall element for detecting a current flowing through the lead storage battery 1. The current sensor 12 can detect a current by a Hall voltage that changes according to a current flowing through the Hall element. The positive electrode external terminal of the lead storage battery 1 is connected to one end of a switch SW1 described later. Further, the positive external terminal and the negative external terminal of the lead storage battery 1 are connected to input terminals of an A / D converter 14 for converting the voltage between both ends of the lead storage battery 1 into a digital value. Output terminals of the A / D converter 14, the current sensor 12, and the temperature sensor 11 for detecting the temperature of the lead storage battery 1 are connected to input ports of the microcomputer 10a, respectively.
[0024]
Further, as described above, the voltage and the like of the lithium secondary battery 2 are detected by the lithium battery control unit 20. That is, the negative electrode external terminal of the lithium secondary battery 2 is connected to the ground via a current sensor 22 such as a Hall element that detects a current flowing through the lithium secondary battery 2. Like the current sensor 12, the current sensor 22 can detect a current by a Hall voltage that changes according to a current flowing through the Hall element. The positive electrode external terminal of the lithium secondary battery 2 is connected to one end of a switch SW2 described later. The positive terminal of each cell constituting the lithium secondary battery 2 and the negative terminal of the lowest cell are connected to the input terminal of a voltage measuring circuit 25 for measuring the voltage of each cell. The voltage measurement circuit 25 can be configured by a differential amplifier circuit or the like that converts the voltage of each cell to a voltage based on the negative terminal. The output terminal of the voltage measurement circuit 25 is connected to an A / D input port of the microcomputer 20a for A / D converting the voltage of the cell. Further, the voltage measurement circuit 25 is connected to a cell designation port of the microcomputer 20a to receive designation of a cell whose voltage is to be measured from the microcomputer 20a.
[0025]
The positive terminal of each unit cell is connected to one end of a bypass resistor R for capacity adjustment (the same resistance value for each unit cell), and the other end of the bypass resistor R is connected to one end of a switch SW for adjusting the capacity of the unit cell. It is connected to the. The other end of the switch SW is connected to the negative terminal of each cell. The switch SW is connected to an output port of the microcomputer 20a that outputs a control signal (high-level signal and low-level signal described later). Accordingly, when the switch SW is turned on by the control signal from the microcomputer 20a, the current flowing through the unit cells is consumed by the bypass resistor R, and the capacity of each unit cell can be adjusted. Output terminals of the current sensor 22 and the temperature sensor 21 for detecting the temperature of the lithium secondary battery 2 are connected to input ports of the microcomputer 20a, respectively.
[0026]
Further, the motor generator 3 is switch-controlled by the microcomputer 30a via the switch control unit 5. One of the input / output terminals of the motor generator 3 is connected to one end of a switch SW3 whose other end is connected to the connection point P, and the other of the input / output terminals is connected to the ground. The switch SW3 is connected to an output port of the microcomputer 30a that outputs a control signal. Further, the microcomputer 30a has an output port for outputting a control signal to the switches SW1, SW2 and a switch SW4 described later.
[0027]
The other ends of the switches SW1 and SW2 are connected to the connection point P. Further, the other end of the accessory 4 is connected to the connection point P via a regulator 6 that limits a current flowing through the accessory 4. A switch SW4 is connected to the regulator 6 in parallel, and the switch SW4 is turned off by a control signal from the microcomputer 30a only when regenerative power is supplied from the motor generator 3 described above. Therefore, normally (except when the motor generator 3 functions as a generator), the switch SW4 is turned on, and power is supplied to the auxiliary device 4 from the lead storage battery 1 and / or the lithium secondary battery 2.
[0028]
For the switches SW1, SW2, SW3, SW4, and SW described above, for example, an FET that functions as a switch element can be used. That is, the output port of the microcomputer is connected to the gate of the FET. Therefore, when a weak high-level signal is input from the output port of each microcomputer to the gate of the FET, a current flows between the drain and the source, and the switch is turned on.
[0029]
The microcomputers 10a and 20a are communicably connected to the microcomputer 30a via the I / O 8. Therefore, the microcomputers 10a and 20a capture the data of the voltage, current and temperature of the lead-acid battery 1 and the data of the voltage of each cell and the current and temperature of the lithium secondary battery 2 respectively, and transfer the captured data to the microcomputer 30a. For example, it is possible to transmit by serial communication.
[0030]
(motion)
First, the control range of the state of charge of the lead storage battery 1 and the lithium secondary battery 2 will be described.
[0031]
As shown in FIG. 3, lead storage battery 1 is charged when motor generator 3 functions as an alternator. That is, charging of the lead storage battery 1 is started when the state of charge is less than 60%, and is stopped when the state of charge exceeds 90%. Therefore, the state of charge of the lead storage battery 1 is maintained at 60 to 90%. The lithium secondary battery 2 is charged when the motor generator 3 functions as an alternator or a generator. That is, charging of the lithium secondary battery 2 by the alternator function is started when the state of charge is less than 5%, and stopped when the state of charge exceeds 50%. Therefore, the state of charge of the lithium secondary battery 2 is maintained at 5 to 50%. The lithium secondary battery 2 is allowed to be charged up to 95% by the generator function.
[0032]
On the other hand, when the state of charge of the lithium secondary battery 2 is less than 30%, except for the time of large current discharge described later, both the lead storage battery 1 and the lithium secondary battery 2 are discharged, and the state of charge of the lithium secondary battery 2 becomes When it is 30% or more, the battery is discharged only from the lithium secondary battery 2. In FIG. 3, Pb represents the lead storage battery 1 and Li represents the lithium secondary battery 2 (the same applies to Table 3 described later).
[0033]
For example, in the (1) Li discharge state in FIG. 3, since the charge state of the lithium secondary battery 2 is 30% or more, only the lithium secondary battery 2 is discharged. (2) In the Li and Pb discharge states, since the state of charge of the lithium secondary battery 2 is less than 30%, both the lithium secondary battery 2 and the lead storage battery 1 are discharged. (3) In the Li state of charge, the state of charge of the lithium secondary battery 2 has dropped to less than 5%, so that the lithium secondary battery 2 is charged by the alternator function of the motor generator 3. In this state, charging / discharging of the lead storage battery 1 is stopped, and electric power is supplied to the auxiliary device 4 from the alternator. When the state of charge of the lithium secondary battery 2 exceeds 50%, the charging is stopped. (4) In the Li discharge state, only the lithium secondary battery 2 is discharged. In this state, since the state of charge of the lithium secondary battery 2 is 30% or more, similarly to the above-described (1) Li discharge state, the lead storage battery 1 is not discharged. (5) In the regenerative charging state, the lithium secondary battery 2 is charged by the generator function of the motor generator 3. In this state, the lithium secondary battery 2 is allowed to be charged up to a charged state of 95%. (6) In the Li discharge state, only the lithium secondary battery 2 is discharged. (7) In the Li and Pb discharge states, since the state of charge of the lithium secondary battery 2 is less than 30%, both the lithium secondary battery 2 and the lead storage battery 1 are discharged. (8) In the Pb charge state, since the charge state of the lead storage battery 1 has dropped to less than 60%, the lead storage battery 1 is charged by the alternator function. In this state, charging and discharging of the lithium secondary battery 2 are stopped, and electric power is supplied to the auxiliary device 4 from the alternator. When the state of charge of the lead storage battery 1 exceeds 90%, charging is stopped.
[0034]
Next, the calculation of the state of charge of the lead storage battery 1 and the lithium secondary battery 2 will be described.
[0035]
The microcomputer 30a supplies power to the microcomputer 10a from the power supply unit (not shown) once every predetermined time (for example, 6 hours) while the vehicle is parked (before the ignition switch of the vehicle is at the ON position). . The microcomputer 10a detects the open circuit voltage OCV and temperature data of the lead storage battery 1 and sends them to the microcomputer 30a via the I / O 8. The microcomputer 30a stops the power supply to the microcomputer 10a after receiving the data from the microcomputer 10a, and according to the battery state map of the lead storage battery 1 stored in the ROM of the microcomputer 30a in advance and expanded in the RAM in the initial setting, The remaining capacity Qres and the state of charge SOC of the lead storage battery 1 are calculated and stored in the RAM.
[0036]
The calculation method will be described in detail. As shown in Table 2, for example, the battery state map is developed in the RAM in a state where the open circuit voltage OCV, the remaining capacity Qres, the state of charge SOC, and the like correspond to each other. Table 2 shows an example at a temperature of 25 ° C. and a current of 250 A.
[0037]
[Table 2]

[0038]
The microcomputer 30a first corrects the open circuit voltage of the lead storage battery 1 at the temperature received from the microcomputer 10a to the open circuit voltage at 25 ° C. As shown in FIG. 4, in the RAM of the microcomputer 30a, for example, a temperature-open circuit voltage correction map for the open circuit voltage at 25 ° C. is developed. The microcomputer 30a adds an open-circuit voltage correction value obtained by using an interpolation method to the received open-circuit voltage to obtain an open-circuit voltage at 25 ° C. Next, the microcomputer 30a calculates the remaining capacity Qres and the state of charge SOC of the lead storage battery 1 from the open circuit voltage at 25 ° C. by using the battery state map shown in Table 2 by using the interpolation method, and stores them in the RAM.
[0039]
When the ignition switch of the vehicle is at the ON position, the microcomputer 30a supplies power to the microcomputer 10a from a power supply unit (not shown). As a result, the microcomputer 10a detects the temperature of the lead storage battery 1 and detects the current of the lead storage battery 1 and integrates the detected currents. Every predetermined time (for example, 10 seconds), the integrated electric quantity (the integrated current And the temperature of the lead storage battery 1 are sent to the microcomputer 30a. The microcomputer 30a calculates the current remaining capacity of the lead-acid battery 1 by sequentially adding (decreasing) the accumulated electric quantity received from the microcomputer 10a to the remaining capacity Qres of the lead-acid battery 1 stored in the RAM. A current state of charge SOC corresponding to the current state of charge is calculated from the battery state map.
[0040]
On the other hand, the microcomputer 30a uses a battery state map of the lithium secondary battery 2 developed in the RAM of the microcomputer 30a and a temperature-open-circuit voltage correction map similar to that shown in FIG. The remaining capacity Qres and the state of charge SOC of the lithium secondary battery 2 are calculated.
[0041]
The microcomputer 20a differs from the microcomputer 10a in detecting the open-circuit voltage of the lead-acid battery 1 in that the microcomputer 20a detects the open-circuit voltage for each unit cell. That is, the microcomputer 20a specifies the cell to be measured from the cell specification port to the voltage measurement circuit 25, and thereby the voltage of the cell to be measured (open circuit voltage) from the voltage measurement circuit 25 via the A / D input port. Take in. The microcomputer 30a receives the temperature and each cell voltage from the microcomputer 20a, corrects each cell voltage to a voltage at 25 ° C., and as shown in FIG. 5, a temperature-open circuit voltage correction map (or a relational expression). To calculate the state of charge SOC of each cell. In addition, in a single cell using amorphous carbon as the negative electrode active material, when the open circuit voltage is y and the charged state is x, y = −5E−0.7x ³ + 6E-0.6x ² + 0.0168x + 2.8971 (convergence radius R ² = 0.9994). Further, the microcomputer 30a calculates the average state of charge of all the cells as the state of charge SOC of the lithium secondary battery 2.
[0042]
Further, the microcomputer 30a determines, for each cell, whether or not there is a cell whose (state of charge SOC of the relevant cell−average state of charge of all cells) exceeds 5 points (capacity adjustment target). When the determination is affirmative, the capacity adjustment time t depending on the resistance value of the bypass resistor R is calculated only for the unit cell, and the status flag indicating that the capacity adjustment is not completed is changed from 0 to 1. I do. The calculation of the capacity adjustment time t is disclosed in, for example, Japanese Patent Application Laid-Open No. 2000-313443.
[0043]
Next, charge / discharge control of the lead storage battery 1 and the lithium secondary battery 2 will be described mainly for the microcomputer 30a.
[0044]
As shown in Table 3 below, the microcomputer 30a switches the functions of the switches SW1, SW2, SW3 and the motor generator 3 based on the vehicle state and the charging state, thereby charging and discharging the lead storage battery 1 and the lithium secondary battery 2. Control.
[0045]
1. Charge and discharge control during vehicle parking
<Ignition switch off position>
The microcomputer 30a turns off the switches SW1, SW2, and SW3 when the ignition switch is at the off position. As a result, the lead storage battery 1 and the lithium secondary battery 2 enter a charge / discharge pause state except for a small amount of power supplied to the microcomputer 30a (see Table 3 (4) below). Note that the microcomputer 30a calculates the state of charge of the lead storage battery 1 and the lithium secondary battery 2 as described above.
[0046]
<Ignition switch on position>
When the ignition switch is at the ON position, the microcomputer 30a determines whether the state of charge of the lead storage battery 1 stored in the RAM is less than 60% and the state of charge of the lithium secondary battery 2 is less than 5%. If the determination is affirmative, the display panel in the driver's seat displays that charging is required. If the determination is negative, the switch SW2 is turned on (switches SW1 and SW3: off). Thereby, the lithium secondary battery 2 is discharged by supplying power to the auxiliary device 4.
[0047]
[Table 3]

[0048]
<Ignition switch start position>
When the ignition switch is located at the start position, the microcomputer 30a makes an affirmative determination (when the state of charge of the lead storage battery 1 is less than 60% and the state of charge of the lithium secondary battery 2 is less than 5%) The switching control unit 5 is switched so that the motor generator 3 functions as a motor, and the switches SW1, SW2, and SW3 are turned on to apply a large current from both the lead storage battery 1 and the lithium secondary battery 2 to the ignition plug of the engine. Supply. When the engine starts, the microcomputer 30a switches the motor generator 3 to the alternator and turns off the switch SW1 (switches SW2 and SW3: on state). Thereby, the lithium secondary battery 2 is charged until the state of charge becomes 50% (details will be described later). On the other hand, when the ignition switch is at the start position, the microcomputer 30a makes a negative determination (when the state of charge of the lead storage battery 1 is 60% or more or the state of charge of the lithium secondary battery 2 is 5% or more). Makes the motor generator 3 function as a motor and turns on the switches SW1 and SW3 (switch SW2: on state). Thereby, a large current is supplied to motor generator 3 from both lead storage battery 1 and lithium secondary battery 2.
[0049]
2. Charge and discharge control during vehicle running
<Motor drive>
After starting the vehicle with the motor instead of the engine, the microcomputer 30a turns on the switches SW1, SW2, and SW3 when it is determined that the vehicle is accelerating from the change in the vehicle speed v (dv / dt >> 0). As a result, a large current is supplied to the motor and the auxiliary machine 4 from both the lead storage battery 1 and the lithium secondary battery 2 (see Table 3 (1)). On the other hand, when the microcomputer 30a determines that the vehicle is not in the acceleration state (dv / dt is almost 0), the microcomputer 30a determines whether or not the state of charge of the lithium secondary battery 2 is 30% or more. The switch SW1 is turned off, the switches SW2 and SW3 are turned on, and when a negative determination is made, the switches SW1, SW2 and SW3 are turned on. Thus, when the state of charge of the lithium secondary battery 2 is 30% or more, power from only the lithium secondary battery 2 is used, and when the state of charge is less than 30%, power from both the lead storage battery 1 and the lithium secondary battery 2 is used. It is supplied to the motor and the auxiliary machine 4 (see Table 3 (2)).
[0050]
In addition, the microcomputer 30a determines the state of charge of the lead storage battery 1 in (1) an accelerated running state, (2) a low speed running state, or a state in which the engine is started because the charged state of the lithium secondary battery 2 is less than 5%. Is less than 60% or the state of charge of the lithium secondary battery 2 is less than 5%, the engine is started by the rotational force of the motor, the motor generator 3 is switched to the alternator, and the switch SW1 or the switch SW2 is turned on. Switch SW3 is turned on. Thereby, the lead storage battery 1 or the lithium secondary battery 2 is charged (details will be described later). When the vehicle speed is, for example, 30 km / h or more, the microcomputer 30a starts the engine, turns on the switch SW2, and turns off the switch SW3. As a result, the vehicle is driven by the engine, and the auxiliary machine 4 is supplied with electric power from the lithium secondary battery 2.
[0051]
<Engine drive>
The microcomputer 30a determines whether or not the state of charge of the lithium secondary battery 2 is 30% or more when the vehicle is running by driving the engine. If the determination is affirmative, the microcomputer 30a turns off the switch SW1 and turns on the switch SW2. When the judgment is negative, the switches SW1 and SW2 are turned on. Thus, when the state of charge of the lithium secondary battery 2 is 30% or more, power from only the lithium secondary battery 2 is used, and when the state of charge is less than 30%, power from both the lead storage battery 1 and the lithium secondary battery 2 is used. It is supplied to the auxiliary machine 4 (see Table 3 (3)). When determining that the state of charge of the lead storage battery 1 is less than 60% or the state of charge of the lithium secondary battery 2 is less than 5%, the microcomputer 30a switches the motor generator 3 to the alternator and switches the switch SW1 or the switch SW2. The ON state and the switch SW3 are turned ON. Thereby, the lead storage battery 1 or the lithium secondary battery 2 is charged (details will be described later).
[0052]
<Idle stop>
The microcomputer 30a determines whether or not the state of charge of the lithium secondary battery 2 is 30% or more as in the case of the above-described engine running, when the engine driving is stopped during a temporary stop during running (idle stop state). The switches SW1, SW2, and SW3 are controlled in accordance with the determination of (1) to supply power to the auxiliary machine 4. Further, when the vehicle is restarted after the idle stop, the above-mentioned (1) accelerated traveling state is set.
[0053]
<Charging by alternator function>
When the microcomputer 30a determines that the state of charge of the lithium secondary battery 2 is less than 5% during the operation of the engine, the microcomputer 30a switches the motor generator 3 to the alternator, turns off the switch SW1, and turns off the switches SW2 and SW3. Turn on. Thereby, the lithium secondary battery 2 is charged by the electric power supplied from the alternator (see Table 3 (5)). Further, the microcomputer 30a checks the above-mentioned status flag, and notifies the microcomputer 20a of the ID of the cell whose capacity is to be adjusted and the capacity adjustment time t when the capacity adjustment of the cell is not completed. Thereby, the microcomputer 20a adjusts the capacity of the unit cell whose capacity is to be adjusted by turning on the switch SW of the unit cell notified from the microcomputer 30a during the capacity adjustment time t. When the state of charge of the lithium secondary battery 2 exceeds 50%, the microcomputer 30a turns off the switch SW3 (switch SW1: off state, switch SW2: on state), and changes the state flag from 1 to 0. . As a result, charging of the lithium secondary battery 2 is stopped, the state of charge of all the cells becomes substantially uniform at 50%, and power supply from the lithium secondary battery 2 to the auxiliary machine 4 is started. Note that the capacity adjustment is performed only once during the first charge of the lithium secondary battery 2 after calculating the state of charge from the above-described open circuit voltage.
[0054]
When the microcomputer 30a determines that the state of charge of the lead storage battery 1 is less than 60% as described above, the microcomputer 30a switches the motor generator 3 to the alternator, turns on the switches SW1 and SW3, and turns off the switch SW2. . Thereby, the lead storage battery 1 is charged by the electric power supplied from the alternator. When the state of charge of the lead storage battery 1 exceeds 90%, the microcomputer 30a turns off the switches SW1 and SW3 and turns on the switch SW2. Thereby, charging of the lead storage battery 1 is stopped, and power supply from the lithium secondary battery 2 to the auxiliary machine 4 is started.
[0055]
<Charging with regenerative power>
When the vehicle is in the braking state (dv / dt << 0), the microcomputer 30a determines whether the state of charge of the lithium secondary battery 2 is less than 75%. When the determination is affirmative, the motor generator 3 is switched to the generator, and the switch SW1 is turned off and the switches SW2 and SW3 are turned on. When the determination is negative, the switches SW1 and SW3 are turned off and the switch SW2 is turned on. Power is supplied to the auxiliary device 4 from the lithium secondary battery 2. As a result, when the state of charge of the lithium secondary battery 2 is less than 75%, the lithium secondary battery 2 is charged with regenerative power, and when the state of charge is 75% or more, reception of regenerative power is not started ( Table 3 (6)). When the state of charge of the lithium secondary battery 2 exceeds 95% by charging with the regenerative power, the microcomputer 30a turns off the switch SW3 (switch SW1: off state, switch SW2: on state). As a result, charging of the lithium secondary battery 2 with regenerative power is stopped, and power supply from the lithium secondary battery 2 to the auxiliary machine 4 is started. When the ignition switch is located at the off position, the above-mentioned (4) parking state is established.
[0056]
(Action)
Next, an operation of the traveling vehicle power supply system 50 of the present embodiment will be described.
[0057]
In the traveling vehicle power supply system 50 of the present embodiment, the microcomputer 30a calculates the temperature based on the open circuit voltage OCV and temperature data of each of the lead storage battery 1 and the lithium secondary battery 2 received from the microcomputers 10a and 20a while the vehicle is parked. The remaining capacity Qres of the lead storage battery 1 and each of the cells is calculated based on the corrected open circuit voltage, and then the integrated amount of electricity is added to or subtracted from the calculated remaining capacity Qres, thereby obtaining the current values of the lead storage battery 1 and the lithium secondary battery 2. Is calculated. For this reason, the state of charge is calculated every predetermined time from the temperature, open circuit voltage, and current data, so that the state of charge of the lead storage battery 1 and the lithium secondary battery 2 can be grasped with high accuracy.
[0058]
When the state of charge of the lead storage battery 1 and / or the lithium secondary battery 2 is less than a predetermined lower limit, the microcomputer 30a controls the functions of the motor generator 3 and the switches SW1 to SW3 so that the lead storage battery 1 and / or Alternatively, charging of the lithium secondary battery 2 is started, and charging is stopped when the state of charge exceeds a predetermined upper limit. Therefore, the state of charge of the lead storage battery 1 and the state of charge of the lithium secondary battery 2 are each maintained within a predetermined range. Therefore, in the traveling vehicle power supply system 50 of the present embodiment, the lead storage battery 1 and the lithium secondary battery 2 can be prevented from being in an overdischarged state and an overcharged state, and the lead storage battery 1 and / or the lithium secondary battery 2 can be prevented. Since the electric power required for starting the engine is appropriately supplied from the secondary battery 2, the engine can be reliably started after the idle stop.
[0059]
Furthermore, in the traveling vehicle power supply system 50 of the present embodiment, since the charging of the lithium secondary battery 2 with the regenerative power is allowed up to a state of charge of 95%, the lithium secondary battery 2 can sufficiently accept the regenerative power. it can. Further, when the state of charge of the lithium secondary battery 2 is 75% or more, the regenerative power is not started to be received, so that the lithium secondary battery 2 can be prevented from being overcharged. Conversely, when the state of charge of the lithium secondary battery 2 is less than 5%, the lithium secondary battery 2 is charged by the alternator function of the motor generator 3 until the state of charge becomes 50%, so that the overdischarge state can be prevented.
[0060]
Furthermore, in the traveling vehicle power supply system 50 of the present embodiment, the microcomputer 20a includes a switch SW connected in parallel to a unit cell whose capacity is to be adjusted while the lithium secondary battery 2 is being charged by the alternator function of the motor generator 3. Is turned on during the capacity adjustment time t to cause the bypass resistor R to heat the charging current. For this reason, since the variation in the state of charge of each unit cell is made uniform, it is possible to prevent a reduction in the life of the lithium secondary battery 2 caused by a unit cell having a different capacity acting as a load on another unit cell.
[0061]
Furthermore, in the traveling vehicle power supply system 50 of the present embodiment, the microcomputer 30a switches the switches SW1 to SW3 so that the lithium secondary battery 2 is discharged only from the lithium secondary battery 2 when the state of charge is equal to or higher than a predetermined value. Control. For this reason, since the discharge from the lithium secondary battery 2 is prioritized, the utilization efficiency of the lithium secondary battery 2 having excellent power acceptability can be improved, and, as a result, the lead storage battery 1 and the entire lithium secondary battery 2 can be used. Efficiency can be improved.
[0062]
Further, the microcomputer 30a operates the switches SW1 to SW4 so as to discharge from both the lead storage battery 1 and the lithium secondary battery 2 when the state of charge of the lithium secondary battery 2 is less than a predetermined value or when the vehicle is in an accelerated running state. By controlling the SW3, it is possible to appropriately supply a large amount of electric power in combination with the lead storage battery 1 having a large capacity, and to reliably start the vehicle by the motor drive even if the current consumption of the auxiliary equipment 4 is large. Can be. Therefore, even after the idle stop, the electric power of the large current is appropriately supplied, so that the vehicle can be reliably started. Therefore, especially in a crowded city area, the use of the engine is reduced, and it is possible to deal with environmental problems.
[0063]
In the present embodiment, an example has been described in which the microcomputers 10a and 20a respectively detect currents flowing through the lead storage battery 1 and the lithium secondary battery 2 and communicate with the microcomputer 30a. However, the current may be detected by the microcomputer 30a. Good. With this configuration, the microcomputer 30a can calculate the state of charge without communication, and thus can more quickly perform the calculation of the state of charge and charge control. Further, in the present embodiment, an example has been described in which the microcomputer 10a detects the voltage of the lead storage battery 1 via the A / D converter 14, but the A / D conversion may be performed by the microcomputer 10a. Further, in the present embodiment, an example in which the switches SW1 to SW3 are controlled by the microcomputer 30a has been described. For example, the switch SW2 may be controlled by the microcomputer 20a. Further, in the present embodiment, an example is shown in which the microcomputers 10a and 20a are provided in addition to the microcomputer 30a. However, the microcomputer 30a alone or the microcomputers 20a and 30a detect voltage and the like, calculate the state of charge, and perform charge control. You may. By doing so, the communication time can be shortened, and the calculation of the state of charge and the charge control can be performed more quickly.
[0064]
Further, in the present embodiment, an example has been described in which charge control is performed such that the state of charge of the lead storage battery 1 is in the range of 60 to 90% and the state of charge of the lithium secondary battery 2 is in the range of 5 to 50%. The present invention is not limited to this. For example, the predetermined range may be set according to the amount of power required for starting the vehicle or the amount of power regenerated from motor generator 3.
[0065]
Further, in the present embodiment, the motor generator 3 functioning as a motor, an alternator and a generator has been exemplified. However, the alternator for charging the lead storage battery 1 and / or the lithium secondary battery 2 while the engine is running is separated from the motor generator. You may make it comprise.
[0066]
Furthermore, in the present embodiment, an example in which the capacity of the unit cell is adjusted when the lithium secondary battery 2 is charged with the power from the alternator has been described. However, the present invention is not limited to this. The capacity adjustment may be performed in the discharge state or the rest state of the secondary battery 2.
[0067]
Furthermore, in the present embodiment, except when the state of charge of the lithium secondary battery 2 is less than 30% from both the lead storage battery 1 and the lithium secondary battery 2 at the time of acceleration traveling requiring a large current, or at the time of low speed traveling. Although an example in which power is supplied to the motor only from the lithium secondary battery 2 has been described, power may be supplied from both the lead storage battery 1 and the lithium secondary battery 2 until the engine is started. By doing so, the on / off control of the switches SW1 to SW3 can be simplified.
[0068]
Further, in the present embodiment, an example in which the lead storage battery 1 is charged only with the electric power from the alternator has been described. However, since the lead storage battery 1 and the lithium secondary battery 2 can be connected in parallel, for example, in a parking state, the lithium storage battery 1 is charged. The switches SW1 and SW2 may be turned on when the state of charge of the secondary battery is 20% or more, and power may be supplied from the lithium secondary battery 2 to the lead storage battery 1 to charge the lead storage battery 1.
[0069]
Furthermore, in this embodiment, an example has been described in which the state of charge is obtained by temperature correction of the open-circuit voltage, but a temperature-charge state correction map may be created in advance and the state of charge may be temperature corrected.
[0070]
Furthermore, in the present embodiment, the 36V-based lead storage battery 1 is exemplified as the aqueous secondary battery group, and the 36V-based lithium secondary battery 2 is exemplified as the non-aqueous secondary battery group. However, the present invention is not limited to this. However, the present invention is also applicable to a case where a 12V-based lead storage battery, a 12V-based lithium secondary battery, a nickel-hydrogen battery, or the like is used.
[0071]
【The invention's effect】
As described above, according to the present invention, the state of charge of each battery group is calculated from the current and the voltage by the state of charge calculation unit, so that the state of charge can be accurately detected, and the state of charge control unit As a result, the respective battery groups are controlled to be charged within a predetermined range, so that the electric power required for starting the engine can be appropriately supplied, and the engine after the idle stop can be surely restarted during the ISS. The effect can be obtained.
[Brief description of the drawings]
FIG. 1 is a schematic block diagram of a power supply system for a traveling vehicle according to an embodiment to which the present invention can be applied.
FIG. 2 is a block circuit diagram of the traveling vehicle power supply system of the embodiment.
FIG. 3 is an explanatory diagram schematically showing a control range of a state of charge of a lead storage battery and a lithium secondary battery.
FIG. 4 is a graph schematically showing a correspondence between a temperature of a lead storage battery and an open-circuit voltage correction value.
FIG. 5 is a graph schematically showing a correspondence between a state of charge of a lithium ion secondary battery and an open circuit voltage.
[Explanation of symbols]
1 Lead acid battery (aqueous solution type secondary battery group)
2 Lithium secondary batteries (non-aqueous secondary batteries)
10 Lead battery detector (part of charge state calculator)
20 Lithium battery control unit (part of charge state calculation unit)
30 Vehicle side control unit (part of charge state calculation unit, part of charge state control unit)
50 Power supply system for running vehicles
R Bypass resistance (part of bypass open circuit)
SW switch (part of bypass open circuit)
SW1 switch (part of opening to start charging, part of opening to stop charging)
SW2 switch (part of opening to start charging, part of opening to stop charging)
SW3 switch (part of opening to start charging, part of opening to stop charging)

Claims (8)

A traveling vehicle power supply system in which an aqueous secondary battery group connected to a plurality of aqueous secondary batteries and a non-aqueous secondary battery group connected to a plurality of non-aqueous secondary batteries can be connected in parallel,
The current and voltage flowing through the aqueous secondary battery group and the non-aqueous secondary battery group are measured, and the charging of the aqueous secondary battery group and the non-aqueous secondary battery group is performed based on the measured current and voltage. A charge state calculation unit for calculating a state;
A charge state control unit that performs charge control to maintain the charge states of the aqueous secondary battery group and the non-aqueous secondary battery group in predetermined ranges based on the charge state calculated by the charge state calculation unit,
A power supply system for a traveling vehicle, comprising: The said aqueous solution type | system | group secondary battery group is comprised with the lead storage battery connected in series, The said non-aqueous secondary battery group is comprised with the lithium secondary battery connected in series, The Claim 1 characterized by the above-mentioned. The power supply system for a traveling vehicle according to the above. The power supply system for a traveling vehicle according to claim 2, wherein the lead storage battery is a control valve type lead storage battery. The power supply system for a traveling vehicle according to claim 2, wherein the lithium secondary battery is a lithium ion secondary battery. The charge state control unit, when the individual charge state of the non-aqueous secondary battery calculated by the charge state calculation unit is higher than the average charge state of the non-aqueous secondary battery, the non-aqueous system with a high charge state The power supply system for a traveling vehicle according to any one of claims 1 to 4, further comprising a bypass circuit that bypasses a charging current flowing through the secondary battery. The charge state control unit includes a circuit that starts charging the aqueous secondary battery group and the non-aqueous secondary battery group when the charge state is lower than a lower limit value of the predetermined range. The power supply system for a traveling vehicle according to any one of claims 1 to 5. The charge state control unit includes a circuit that stops charging of the aqueous secondary battery group and the non-aqueous secondary battery group when the charge state is higher than an upper limit value of the predetermined range. The power supply system for a traveling vehicle according to any one of claims 1 to 6. The charge state control unit, when the charge state of the non-aqueous secondary battery group is equal to or greater than a predetermined charge state within the predetermined range, supplies power to the discharge load from the non-aqueous secondary battery group, When the state of charge of the secondary battery group is lower than the predetermined state of charge or when supplying power to the vehicle traveling motor, the discharge load is supplied from both the aqueous secondary battery group and the non-aqueous secondary battery group. The power supply system for a traveling vehicle according to any one of claims 1 to 7, wherein control is performed to supply electric power.

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