JP6693350B2 - Voltage equalization method for multiple battery stacks - Google Patents

Voltage equalization method for multiple battery stacks Download PDF

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JP6693350B2
JP6693350B2 JP2016173756A JP2016173756A JP6693350B2 JP 6693350 B2 JP6693350 B2 JP 6693350B2 JP 2016173756 A JP2016173756 A JP 2016173756A JP 2016173756 A JP2016173756 A JP 2016173756A JP 6693350 B2 JP6693350 B2 JP 6693350B2
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battery
smr
voltage
relay
power supply
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JP2018042342A (en
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勇二 西
勇二 西
宏昌 田中
宏昌 田中
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Toyota Motor Corp
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/70—Energy storage systems for electromobility, e.g. batteries

Description

本開示は、複数の電池スタックの電圧均等化方法に関する。   The present disclosure relates to a voltage equalization method for a plurality of battery stacks.

車両等に搭載される電源装置は、所定の高電圧及び大電流を出力するために、複数の電池スタックを直列及び並列接続して構成される。例えば、特許文献１には、電動機に対しＳＭＲ（Ｓｙｓｔｅｍ Ｍａｉｎ Ｒｅｌａｙ）と呼ばれる電力用リレーを介して、複数の電池スタックが並列接続される例が示される。   A power supply device mounted on a vehicle or the like is configured by connecting a plurality of battery stacks in series and in parallel in order to output a predetermined high voltage and large current. For example, Patent Document 1 shows an example in which a plurality of battery stacks are connected in parallel to an electric motor via a power relay called SMR (System Main Relay).

電源装置が動作中は、各電池スタックが充放電しているので、各電池スタックの開放回路電圧（Ｏｐｅｎ Ｃｉｒｃｕｉｔ Ｖｏｌｔａｇｅ：ＯＣＶ）が測定できない。電源装置が動作停止するとＳＭＲが遮断されるので、各電池スタックの端子間電圧であるＯＣＶが測定できる。そのときに各電池スタックの端子間電圧の間に電圧差が生じていることがあり、この状態のままで、電源装置を再起動すると、並列接続されている電池スタック間の電圧差によってＳＭＲに突入電流が流れ、ＳＭＲの耐久性が低下する。これを防ぐために、各電池スッタック間の電圧均等化が行われる。   Since the battery stacks are charged and discharged while the power supply device is operating, the open circuit voltage (OCV) of each battery stack cannot be measured. When the power supply device stops operating, the SMR is cut off, so that the OCV, which is the voltage between terminals of each battery stack, can be measured. At that time, a voltage difference may occur between the terminal voltages of the battery stacks, and if the power supply device is restarted in this state, SMR will be generated due to the voltage difference between the battery stacks connected in parallel. Inrush current flows, and the durability of SMR decreases. To prevent this, voltage equalization is performed between the battery stacks.

特開２０１０−２４６２８５号公報JP, 2010-246285, A

従来技術において、複数の電池スタックの電圧均等化方法として、１０数ｍＡ〜数１００ｍＡ程度の均等化電流を必要な電池スタックに流す。この程度の均等化電流では、各電池スタック間の電圧差が大きい場合等のときに電圧均等化が終了するまで長時間を要し、電源装置の次回起動のタイミングに間に合わないことが生じる。均等化電流を増大させるには、均等化回路等のコストが増大する。そこで、ＳＭＲの耐久性を維持しながら、適切な電圧均等化を実行できる複数の電池スタックの電圧均等化方法が要望される。   In the prior art, as a voltage equalization method for a plurality of battery stacks, an equalizing current of about 10 mA to several 100 mA is applied to a required battery stack. With such an equalized current, it takes a long time to complete the voltage equalization when the voltage difference between the battery stacks is large, etc., and it may not be in time for the next startup of the power supply device. To increase the equalizing current, the cost of the equalizing circuit and the like increases. Therefore, there is a demand for a voltage equalization method for a plurality of battery stacks that can perform appropriate voltage equalization while maintaining the durability of SMR.

本開示に係る複数の電池スタックの電圧均等化方法は、正極母線と正極側リレーに接続される正極、及び、負極母線と負極側リレーに接続される負極を有する電池スタックを２つ並列接続し、電流制限抵抗を直列接続したプリチャージリレーを一方側の電池スタックの正極側リレーにのみ並列に接続して構成されて、プリチャージリレー以外をすべてオンして起動し、全てのリレーをオフして動作を停止する電源装置における電池スタックの電圧均等化方法であって、電源装置の動作の停止後において、異なる電池スタック間の電圧差が均等化処理を許可できる所定値範囲内であるか否かを判定し、所定値範囲内の場合には、一方側の電池スタックの正極側リレーをオフのままプリチャージリレーと負極側リレーとをオンし、かつ、他方側の電池スタックの正極側リレーと負極側リレーを共にオンし、電池スタックの間の電圧差が所定の電圧差に低減するまでの所定時間はその状態を維持する。   A voltage equalization method for a plurality of battery stacks according to the present disclosure includes connecting in parallel two battery stacks each having a positive electrode connected to a positive electrode bus and a positive electrode side relay, and a negative electrode connected to a negative electrode bus and a negative electrode side relay. , A precharge relay in which a current limiting resistor is connected in series is connected in parallel only to the positive electrode side relay of the battery stack on one side, and all but the precharge relay are turned on to start and all relays are turned off. A method for equalizing the voltage of a battery stack in a power supply device that stops the operation by checking whether the voltage difference between different battery stacks is within a predetermined value range that allows equalization processing after the operation of the power supply device is stopped. If it is within the predetermined value range, the positive side relay of the battery stack on one side is turned off, the precharge relay and the negative side relay are turned on, and the other side of the battery stack is turned on. Together on the positive electrode side relay and the negative relay pond stack, the voltage difference between the cell stack is a predetermined time to reduce the predetermined voltage difference maintains its state.

上記構成に係る複数の電池スタックの電圧均等化方法によれば、プリチャージリレーを用いて電圧均等化を図れるので、ＳＭＲの耐久性を維持しながら、適切な電圧均等化を実行できる。   According to the voltage equalization method for a plurality of battery stacks according to the above configuration, voltage equalization can be achieved by using the precharge relay, so that appropriate voltage equalization can be performed while maintaining the durability of SMR.

実施の形態に係る複数の電池スタックの電圧均等化方法が適用される電源装置を含む車両駆動システムの構成図である。1 is a configuration diagram of a vehicle drive system including a power supply device to which a voltage equalizing method for a plurality of battery stacks according to an embodiment is applied. 実施の形態に係る複数の電池スタックの電圧均等化方法の手順を示すフローチャートである。6 is a flowchart showing a procedure of a voltage equalizing method for a plurality of battery stacks according to the embodiment. 図２において、動作中の電源装置の各リレーのオンオフを示す図である。FIG. 3 is a diagram showing ON / OFF of each relay of the power supply device in operation in FIG. 2. 図２において、動作停止した電源装置の各リレーのオンオフを示す図である。FIG. 3 is a diagram showing ON / OFF of each relay of the power supply device which has stopped operating in FIG. 2. 図２において、電圧均等化処理中の電源装置の各リレーのオンオフを示す図である。FIG. 3 is a diagram showing ON / OFF of each relay of the power supply device during the voltage equalization process in FIG. 2. 図５に引き続いて実行されるさらなる電圧均等化処理における電源装置の各リレーのオンオフを示す図である。It is a figure which shows ON / OFF of each relay of the power supply device in the further voltage equalization process performed following FIG. 図６の構成を用いる電圧均等化方法の手順を示すフローチャートである。7 is a flowchart showing a procedure of a voltage equalizing method using the configuration of FIG. 6.

以下に図面を用いて、本実施の形態に付き詳細に説明する。以下では、電源装置の負荷として、車両に搭載される回転電機及びその駆動回路を述べるが、これは例示であって、その他の補機等の負荷を含んでもよい。回転電機の数は１つの場合を述べるがこれは説明のための例示であって、複数の回転電機であってよく、これに合わせて複数の駆動回路であってもよい。車両は、回転電機と共にエンジンを搭載するハイブリッド車両であってもよい。
以下では、全ての図面において同様の要素には同一の符号を付し、重複する説明を省略する。 Hereinafter, the present embodiment will be described in detail with reference to the drawings. In the following, as the load of the power supply device, the rotating electric machine mounted on the vehicle and the drive circuit thereof will be described, but this is an example and may include loads of other auxiliary machines and the like. The case where the number of rotating electric machines is one will be described, but this is an example for description, and a plurality of rotating electric machines may be provided, and a plurality of drive circuits may be provided in accordance with this. The vehicle may be a hybrid vehicle equipped with an engine together with a rotating electric machine.
In the following, similar elements are denoted by the same reference symbols in all the drawings, and overlapping description will be omitted.

図１は、複数の電池スタックの電圧均等化方法が適用される電源装置２０を含む車両駆動システム１０の構成図である。以下では、特に断らない限り、「複数の電池スタックの電圧均等化方法」を、電圧均等化方法と呼ぶ。車両駆動システム１０は、回転電機を駆動源とする車両の駆動システムであって、回転電機１２と、その駆動回路１３を構成するインバータ１４、平滑コンデンサ１６、ＤＣ／ＤＣコンバータ１８と、電源装置２０と、電池制御部６０とを含む。回転電機１２およびその駆動回路１３は、電源装置２０に対する充放電の対象である負荷である。回転電機１２及びその駆動回路１３の内容は、周知であるので、詳細な説明を省略する。   FIG. 1 is a configuration diagram of a vehicle drive system 10 including a power supply device 20 to which a voltage equalizing method for a plurality of battery stacks is applied. Hereinafter, the “voltage equalization method for a plurality of battery stacks” will be referred to as a voltage equalization method unless otherwise specified. The vehicle drive system 10 is a drive system for a vehicle that uses a rotary electric machine as a drive source, and includes a rotary electric machine 12, an inverter 14, a smoothing capacitor 16, a DC / DC converter 18, and a power supply device 20 that form a drive circuit 13 for the rotary electric machine 12. And a battery control unit 60. The rotating electrical machine 12 and its drive circuit 13 are loads that are the targets of charging and discharging of the power supply device 20. The contents of the rotary electric machine 12 and its drive circuit 13 are well known, and thus detailed description thereof will be omitted.

電源装置２０は、複数の電池スタックとして２つの電池スタック２２，２４が並列接続された高電圧大電力の直流電源である。電源装置２０の正極母線２６は、駆動回路１３の正極母線となり、電源装置２０の負極母線２８は、駆動回路１３の負極母線となる。正極母線２６、負極母線２８は、高電圧電力線であるので、車両の車体から絶縁されてフローティングの電位とされる。   The power supply device 20 is a high-voltage, high-power DC power supply in which two battery stacks 22 and 24 are connected in parallel as a plurality of battery stacks. The positive electrode busbar 26 of the power supply device 20 becomes the positive electrode busbar of the drive circuit 13, and the negative electrode busbar 28 of the power supply device 20 becomes the negative electrode busbar of the drive circuit 13. Since the positive electrode bus bar 26 and the negative electrode bus line 28 are high voltage power lines, they are insulated from the vehicle body of the vehicle and have a floating potential.

電池スタック２２，２４は、充放電可能な二次電池である。電池スタック２２，２４としては、所定数の電池セルを直列に接続した高電圧組電池が用いられる。電池セルとしては、リチウムイオン電池あるいはニッケル水素電池が用いられる。電池スタック２２，２４の端子間電圧の例を挙げると、約２００Ｖ〜約３００Ｖである。   The battery stacks 22 and 24 are chargeable / dischargeable secondary batteries. As the battery stacks 22 and 24, high voltage assembled batteries in which a predetermined number of battery cells are connected in series are used. As the battery cell, a lithium ion battery or a nickel hydrogen battery is used. An example of the voltage between the terminals of the battery stacks 22 and 24 is about 200V to about 300V.

２つの電池スタック２２，２４を区別するときは、一方側の電池スタック２２、他方側の電池スタック２４と呼ぶ。一方側の電池スタック２２の正極は、電源装置２０の正極母線２６との間に正極側リレー３０が設けられ、負極は、電源装置２０の負極母線２８との間に負極側リレー３２が設けられる。同様に、他方側の電池スタック２４の正極は、電源装置２０の正極母線２６との間に正極側リレー３６が設けられ、負極は、電源装置２０の負極母線２８との間に負極側リレー３８が設けられる。一方側の電池スタック２２と他方側の電池スタック２４の間の相違点は、電流制限抵抗３５を直列接続したプリチャージリレー３４が、一方側の電池スタック２２の正極側リレー３０にのみ並列に設けられることである。   When distinguishing the two battery stacks 22 and 24, they are referred to as a battery stack 22 on one side and a battery stack 24 on the other side. The positive electrode of the battery stack 22 on one side is provided with a positive electrode side relay 30 between it and the positive electrode bus bar 26 of the power supply device 20, and the negative electrode is provided with a negative electrode side relay 32 between it and the negative electrode bus line 28 of the power supply device 20. .. Similarly, the positive electrode of the battery stack 24 on the other side is provided with the positive electrode side relay 36 between it and the positive electrode bus bar 26 of the power supply device 20, and the negative electrode is provided between it and the negative electrode bus line 28 of the power supply device 20. Is provided. The difference between the battery stack 22 on the one side and the battery stack 24 on the other side is that a precharge relay 34 in which a current limiting resistor 35 is connected in series is provided only in parallel with the positive side relay 30 of the battery stack 22 on the one side. Is to be done.

プリチャージリレー３４を含み、正極側リレー３０，３６、負極側リレー３２，３８は、駆動回路１３と電源装置２０との間の大電力のやり取りを遮断または接続する電力用リレーである。これら５つの電力用リレーについて、電池スタック２２，２４との接続関係が分かりやすいように、以下では、特に断らない限り、符号でなく、記号で示す。すなわち、正極側リレー３０，３６は、それぞれＳＭＲ−Ｂ１，ＳＭＲ−Ｂ２と示し、負極側リレー３２，３８は、それぞれＳＭＲ−Ｇ１，ＳＭＲ−Ｇ２と示し、プリチャージリレー３４は、ＳＭＲ−Ｐと示す。ＳＭＲは、システムメインリレーを意味し、Ｂは、電池スタック２２，２４の正極側に接続されることを意味し、Ｇは、電池スタック２２，２４の負極側に接続されることを意味する。Ｂ，Ｇの後の１，２は、それぞれ一方側の電池スタック２２と他方側の電池スタック２４を意味する。Ｐは、プリチャージを意味する。   The positive side relays 30 and 36 and the negative side relays 32 and 38 including the precharge relay 34 are power relays that cut off or connect a large amount of power exchange between the drive circuit 13 and the power supply device 20. In order to make it easy to understand the connection relationship between the five power relays and the battery stacks 22 and 24, the reference numerals will be used instead of the reference numerals unless otherwise specified. That is, the positive side relays 30 and 36 are shown as SMR-B1 and SMR-B2, respectively, the negative side relays 32 and 38 are shown as SMR-G1 and SMR-G2, respectively, and the precharge relay 34 is shown as SMR-P. Show. SMR means a system main relay, B means connected to the positive electrode side of the battery stacks 22 and 24, and G means connected to the negative electrode side of the battery stacks 22 and 24. 1 and 2 after B and G mean the battery stack 22 on one side and the battery stack 24 on the other side, respectively. P means precharge.

ＳＭＲ−Ｐは、電源装置２０が起動するに先立って平滑コンデンサ１６を事前充電（プリチャージ）するリレーである。例えば、電源装置２０を起動させるために、一方側の電池スタック２２について、順序はいずれでもよいが、ＳＭＲ−Ｇ１とＳＭＲ−Ｂ１とを順次接続する際に、平滑コンデンサ１６が未充電であると、その充電のために電流が急激に流れる。この突入電流のために、ＳＭＲ−Ｇ１，ＳＭＲ−Ｂ１の内で、後で接続が行われた方のリレーに溶着が生じる恐れがある。これを防止するために、他方側の電池スタック２４におけるＳＭＲ−Ｂ２、ＳＭＲ−Ｇ２をオフし、一方側の電池スタック２２においてＳＭＲ−Ｇ１をオンとし、ＳＭＲ−Ｂ１をオフとして、ＳＭＲ−Ｐをオンする。ＳＭＲ−Ｐと正極母線２６との間には電流制限抵抗３５が接続されているので、電池スタック２２からの電流は、電流制限抵抗３５を介して平滑コンデンサ１６を充電する。電流制限抵抗３５の抵抗値は、ＳＭＲ−Ｇ１を流れる電流が過大にならないように設定される。これによって、ＳＭＲ−Ｇ１の溶着を防止できる。平滑コンデンサ１６に適切な事前充電が行われた後は、ＳＭＲ−Ｐをオフし、ＳＭＲ−Ｂ１，ＳＭＲ−Ｇ２，ＳＭＲ−Ｂ２を定められた順序で順次オンする。これによって、リレーの溶着を防止しながら、電源装置２０が起動される。   The SMR-P is a relay that pre-charges (pre-charges) the smoothing capacitor 16 before the power supply device 20 is activated. For example, in order to activate the power supply device 20, the battery stack 22 on one side may be in any order, but when the SMR-G1 and SMR-B1 are sequentially connected, the smoothing capacitor 16 is not charged. , Due to the charging, the current suddenly flows. Due to this inrush current, there is a possibility that welding may occur in the relay of the SMR-G1 and SMR-B1 that is connected later. In order to prevent this, the SMR-B2 and SMR-G2 in the battery stack 24 on the other side are turned off, the SMR-G1 is turned on in the battery stack 22 on the one side, the SMR-B1 is turned off, and the SMR-P is turned on. Turn on. Since the current limiting resistor 35 is connected between the SMR-P and the positive electrode bus 26, the current from the battery stack 22 charges the smoothing capacitor 16 via the current limiting resistor 35. The resistance value of the current limiting resistor 35 is set so that the current flowing through the SMR-G1 does not become excessive. This can prevent welding of SMR-G1. After the smoothing capacitor 16 is appropriately precharged, the SMR-P is turned off, and the SMR-B1, SMR-G2 and SMR-B2 are sequentially turned on in a predetermined order. As a result, the power supply device 20 is activated while preventing welding of the relay.

なお、電流制限抵抗３５によって制限された一方側の電池スタック２２からの電流は、一般的な電圧均等化処理で用いられる均等化電流と比較すると、例えば、１桁〜数桁程度大きな電流である。   The current from the battery stack 22 on one side limited by the current limiting resistor 35 is, for example, a current that is larger by one digit to several digits than the equalizing current used in the general voltage equalizing process. ..

図１では、ＳＭＲ−Ｐは、一方側の電池スタック２２のＳＭＲ−Ｂ１に並列に配置されるものとした。これに代えて、ＳＭＲ−Ｐを一方側の電池スタック２２のＳＭＲ−Ｇ１に並列に配置することもできる。一方側の電池スタック２２は、ＳＭＲ−Ｐが配置される側の電池スタックであるので、図１において、電池スタック２４を一方側の電池スタックと呼ぶ場合には、ＳＭＲ−Ｐは、電池スタック２４のＳＭＲ−Ｂ２に並列に配置される。これに代えて、電池スタック２４のＳＭＲ−Ｇ２に並列に配置してもよい。以下では、図１の配置関係とする。   In FIG. 1, the SMR-P is arranged in parallel with the SMR-B1 of the battery stack 22 on one side. Alternatively, the SMR-P may be arranged in parallel with the SMR-G1 of the battery stack 22 on one side. Since the battery stack 22 on the one side is the battery stack on the side where the SMR-P is arranged, when the battery stack 24 is called the battery stack on the one side in FIG. 1, the SMR-P indicates the battery stack 24. SMR-B2 are arranged in parallel. Instead of this, they may be arranged in parallel with the SMR-G2 of the battery stack 24. In the following, the arrangement relationship shown in FIG. 1 is used.

図１において、電圧検出部４０は、一方側の電池スタック２２の端子間電圧Ｖ１を検出する電圧検出手段である。電流検出部４２は、一方側の電池スタック２２を流れる電流Ｉ１を検出する電流検出手段である。電池温度検出部４４は、一方側の電池スタック２２の電池温度θ１を検出する温度検出手段である。同様に、他方側の電池スタック２４に、端子間電圧Ｖ２を検出する電圧検出部４６、電流Ｉ２を検出する電流検出部４８、電池温度θ２を検出する電池温度検出部５０が設けられる。これらの検出データは、それぞれ適当な信号線で電池制御部６０に伝送される。   In FIG. 1, the voltage detection unit 40 is a voltage detection unit that detects the inter-terminal voltage V1 of the battery stack 22 on one side. The current detector 42 is a current detector that detects the current I1 flowing through the battery stack 22 on one side. The battery temperature detector 44 is a temperature detector that detects the battery temperature θ1 of the battery stack 22 on one side. Similarly, the battery stack 24 on the other side is provided with a voltage detector 46 that detects the inter-terminal voltage V2, a current detector 48 that detects the current I2, and a battery temperature detector 50 that detects the battery temperature θ2. These detection data are transmitted to the battery control unit 60 via appropriate signal lines.

起動／停止指令５８は、車両駆動システム１０の動作を全体として制御するシステム制御部から伝送される指令で、電源装置２０を起動する指令、または電源装置２０の動作を停止する指令である。図１ではシステム制御部の図示を省略した。起動／停止指令５８は、適当な信号線で電池制御部６０に伝送される。   The start / stop command 58 is a command transmitted from a system control unit that controls the operation of the vehicle drive system 10 as a whole, and is a command to start the power supply device 20 or a command to stop the operation of the power supply device 20. The system controller is not shown in FIG. The start / stop command 58 is transmitted to the battery control unit 60 via an appropriate signal line.

電池制御部６０は、電源装置２０の５つのリレーＳＭＲ−Ｂ１，ＳＭＲ−Ｇ１，ＳＭＲ−Ｐ，ＳＭＲ−Ｂ２，ＳＭＲ−Ｇ２の動作を全体として制御する。特に、電源装置２０において一方側の電池スタック２２の端子間電圧Ｖ１と、他方側の電池スタック２４の端子間電圧Ｖ２の間に絶対値としての電圧差ΔＶ＝|Ｖ１−Ｖ２|が生じるときに、ΔＶを小さくする電圧均等化処理を行う。かかる電池制御部６０は、車両搭載に適したコンピュータで構成される。   The battery control unit 60 controls the operation of the five relays SMR-B1, SMR-G1, SMR-P, SMR-B2, SMR-G2 of the power supply device 20 as a whole. In particular, when a voltage difference ΔV = | V1-V2 | as an absolute value occurs between the inter-terminal voltage V1 of the battery stack 22 on the one side and the inter-terminal voltage V2 of the battery stack 24 on the other side in the power supply device 20. , .DELTA.V is reduced to perform voltage equalization processing. The battery control unit 60 is composed of a computer suitable for mounting on a vehicle.

コンピュータである電池制御部６０の電圧均等化処理の機能は、電池制御部６０がソフトウェアを実行することで実現でき、具体的には、電池制御部６０が、電圧均等化処理プログラムの各処理手順を実行することで実現される。上記機能の一部をハードウェアで実現してもよい。なお、電池制御部６０を独立のコンピュータとして構成することもできるが、図示しないシステム制御部の機能の一部としてもよい。   The function of the voltage equalization processing of the battery control unit 60, which is a computer, can be realized by executing the software by the battery control unit 60. Specifically, the battery control unit 60 causes the battery control unit 60 to perform each processing procedure of the voltage equalization processing program. It is realized by executing. Some of the above functions may be realized by hardware. The battery control unit 60 may be configured as an independent computer, but may be a part of the function of a system control unit (not shown).

上記構成の作用効果、特に、電池制御部６０の電圧均等化処理の機能について、図２以下を用いて、詳細に説明する。図２は、電圧均等化処理の手順を示すフローチャートである。各手順は、電圧均等化処理プログラムの各処理手順にそれぞれ対応する。   The function and effect of the above configuration, particularly the function of the voltage equalization process of the battery control unit 60 will be described in detail with reference to FIG. FIG. 2 is a flowchart showing the procedure of voltage equalization processing. Each procedure corresponds to each processing procedure of the voltage equalization processing program.

車両制御プログラムが立ち上がると、初期化の後に、電圧均等化処理プログラムも立ち上がる。車両において、回転電機１２と駆動回路１３を動作させるとき、起動／停止指令５８は、電源装置２０の起動指令を電池制御部６０に伝送する。これを受けて、電池制御部６０は、電源装置２０を動作状態にする（Ｓ１０）。   When the vehicle control program starts up, the voltage equalization processing program also starts up after initialization. When the rotating electric machine 12 and the drive circuit 13 are operated in the vehicle, the start / stop command 58 transmits a start command for the power supply device 20 to the battery control unit 60. In response to this, the battery control unit 60 activates the power supply device 20 (S10).

図３は、動作中の電源装置２０の各リレーのオンオフを示す図である。電源装置２０が動作中のときは、ＳＭＲ−Ｂ１，ＳＭＲ−Ｇ１，ＳＭＲ−Ｂ２，ＳＭＲ−Ｇ２がオンとされる。ＳＭＲ−Ｐは、電源装置２０の起動に先立つプリチャージにおいて平滑コンデンサ１６を充電するときにオンされるが、必要な充電が終了すると、オフ状態となる。図１では、プリチャージが終了した後の動作中の電源装置２０の状態を示すので、ＳＭＲ−Ｐはオフ状態である。   FIG. 3 is a diagram showing ON / OFF of each relay of the power supply device 20 during operation. When the power supply device 20 is operating, the SMR-B1, SMR-G1, SMR-B2 and SMR-G2 are turned on. The SMR-P is turned on when the smoothing capacitor 16 is charged in the precharge prior to the activation of the power supply device 20, but is turned off when the necessary charging is completed. FIG. 1 shows the state of the power supply device 20 in operation after the completion of the precharge, so the SMR-P is in the off state.

ＳＭＲ−Ｂ１，ＳＭＲ−Ｇ１がオンするので、一方側の電池スタック２２から電流Ｉ１が正極母線２６側に放電する。同様に、ＳＭＲ−Ｂ２，ＳＭＲ−Ｇ２がオンするので、他方側の電池スタック２４から電流Ｉ２が正極母線２６側に放電する。図３において、流れる電流を太線で示し、電流の方向を矢印で示す。したがって、駆動回路１３へは、（Ｉ１＋Ｉ２）の直流放電電流が供給される。これとは逆に、駆動回路１３から直流充電電流が電池スタック２２，２４に供給されるときは、図３の太線の電流の方向が反対方向となり、電池スタック２２，２４が充電される。   Since SMR-B1 and SMR-G1 are turned on, the current I1 is discharged from the battery stack 22 on one side to the positive electrode bus 26 side. Similarly, since SMR-B2 and SMR-G2 are turned on, the current I2 is discharged from the other side battery stack 24 to the positive electrode bus 26 side. In FIG. 3, the flowing current is indicated by a thick line, and the direction of the current is indicated by an arrow. Therefore, the drive circuit 13 is supplied with the DC discharge current of (I1 + I2). On the contrary, when the DC charging current is supplied from the drive circuit 13 to the battery stacks 22 and 24, the current directions indicated by the thick lines in FIG. 3 are opposite to each other, and the battery stacks 22 and 24 are charged.

なお、図３におけるＶ１，Ｖ２は、電池スタック２２，２４に電流が流れているときの端子間電圧であり、ＣＣＶ（Ｃｌｏｓｅｄ Ｃｉｒｃｕｉｔ Ｖｏｌｔａｇｅ）と呼ばれる。ＣＣＶは、電池スタック２２，２４に電流が流れないときの開放回路電圧ＯＣＶとは異なる。   It should be noted that V1 and V2 in FIG. 3 are inter-terminal voltages when current flows through the battery stacks 22 and 24, and are called CCV (Closed Circuit Voltage). CCV is different from the open circuit voltage OCV when current does not flow in the battery stacks 22 and 24.

図２に戻り、車両の回転電機１２と駆動回路１３に電力の供給が不要となるとき、起動／停止指令５８は、停止指令を電池制御部６０に伝送する。これを受けて、電池制御部６０は、電源装置２０の動作を停止させる（Ｓ１２）。図４は、動作停止した電源装置２０の各リレーのオンオフを示す図である。電源装置２０が動作停止すると、全てのリレーＳＭＲ−Ｂ１，ＳＭＲ−Ｇ１，ＳＭＲ−Ｐ，ＳＭＲ−Ｂ２，ＳＭＲ−Ｇ２がオフされる。   Returning to FIG. 2, when the electric power supply to the rotating electric machine 12 and the drive circuit 13 of the vehicle becomes unnecessary, the start / stop command 58 transmits the stop command to the battery control unit 60. In response to this, the battery control unit 60 stops the operation of the power supply device 20 (S12). FIG. 4 is a diagram showing ON / OFF of each relay of the power supply device 20 which has stopped operating. When the power supply device 20 stops operating, all the relays SMR-B1, SMR-G1, SMR-P, SMR-B2, SMR-G2 are turned off.

このときのＶ１，Ｖ２は、電池スタック２２，２４に電流が流れないときの端子間電圧であり、開放回路電圧ＯＣＶである。開放回路電圧ＯＣＶは、電池スタック２２，２４の充電状態を示すＳＯＣ（Ｓｔａｔｅ Ｏｆ Ｃｈｒａｇｅ）と関連付けることができる。電圧均等化処理は、一方側の電池スタック２２の開放回路電圧ＯＣＶと、他方側の電池スタック２４の開放回路電圧ＯＣＶとの間に電圧差ΔＶがあるときに、その電圧差ΔＶを小さくする処理である。そこで、以下においては、特に断らない限り、電圧すなわち端子間電圧Ｖ１，Ｖ２は、それぞれＳＯＣと関連付けられる開放回路電圧ＯＣＶを指す。   V1 and V2 at this time are inter-terminal voltages when current does not flow in the battery stacks 22 and 24, and are open circuit voltages OCV. The open circuit voltage OCV can be associated with SOC (State Of Charge) indicating the state of charge of the battery stacks 22 and 24. The voltage equalization process is a process of reducing the voltage difference ΔV when there is a voltage difference ΔV between the open circuit voltage OCV of the battery stack 22 on the one side and the open circuit voltage OCV of the battery stack 24 on the other side. Is. Therefore, in the following, unless otherwise specified, the voltages, that is, the inter-terminal voltages V1 and V2 refer to the open circuit voltage OCV associated with the SOC, respectively.

図２に戻り、電源装置２０が動作停止すると、その状態において、一方側の電池スタック２２の端子間電圧Ｖ１と、他方側の電池スタック２４の端子間電圧Ｖ２を取得する（Ｓ１４）。この手順は、電圧検出部４０，４６の検出データを取得することで実行される。Ｖ１，Ｖ２が取得されると、Ｖ１，Ｖ２の間の絶対値としての電圧差ΔＶ＝|Ｖ１−Ｖ２|を算出し、予め定めた第１の所定電圧差ΔＶth1以下であるか否かが判定される（Ｓ１６）。第１の所定電圧差は、５つのリレーのオンオフ制御を行うことで電圧均等化処理が可能か否かの観点から設定される。 Returning to FIG. 2, when the power supply device 20 stops operating, in that state, the inter-terminal voltage V1 of the battery stack 22 on one side and the inter-terminal voltage V2 of the battery stack 24 on the other side are acquired (S14). This procedure is executed by acquiring the detection data of the voltage detection units 40 and 46. When V1 and V2 are acquired, a voltage difference ΔV = | V1−V2 | is calculated as an absolute value between V1 and V2, and whether or not it is equal to or less than a first predetermined voltage difference ΔV th1 determined in advance. It is determined (S16). The first predetermined voltage difference is set from the viewpoint of whether voltage equalization processing is possible by performing on / off control of the five relays.

Ｓ１６の判定が否定されるときは、ΔＶ＞ΔＶth1の場合で、電圧差ΔＶが過大すぎて５つのリレーのオンオフ制御によって電圧均等化処理を行うには適さない。この状態のまま、電源装置２０を再起動すると、過大なΔＶのために、一方側の電池スタック２２と他方側の電池スタック２４との間に大きな突入電流が流れる。再起動に先立って行われるプリチャージ処理ではこの電圧差ΔＶは変化しないので、このΔＶに起因する突入電流で、ＳＭＲ−Ｂ１，ＳＭＲ−Ｇ１，ＳＭＲ−Ｂ２，ＳＭＲ−Ｇ２の内の少なくとも１つが溶着する可能性がある。そこで、Ｓ１６の判定が否定されるときは、電源装置２０について、次回の再起動を禁止する（Ｓ１８）。電源装置２０の再起動が禁止されると、駆動回路１３、回転電機１２に電力が供給されないので、予め定めた診断方法によって、対応策が実施される。 When the determination in S16 is negative, ΔV> ΔV th1 , and the voltage difference ΔV is too large, which is not suitable for performing the voltage equalization process by the on / off control of the five relays. If the power supply device 20 is restarted in this state, a large inrush current flows between the battery stack 22 on one side and the battery stack 24 on the other side due to an excessive ΔV. Since the voltage difference ΔV does not change in the precharge process performed before the restart, at least one of SMR-B1, SMR-G1, SMR-B2 and SMR-G2 is caused by the inrush current resulting from this ΔV. There is a possibility of welding. Therefore, when the determination in S16 is negative, the next restart of the power supply device 20 is prohibited (S18). When the restart of the power supply device 20 is prohibited, electric power is not supplied to the drive circuit 13 and the rotary electric machine 12, and therefore a countermeasure is implemented by a predetermined diagnostic method.

Ｓ１６の判定が肯定されると、次にΔＶが予め定めた第２の所定電圧差ΔＶth2以上であるか否かが判定される（Ｓ１８）。第２の所定電圧差は、誤差範囲よりも大きな電圧差であって、５つのリレーのオンオフ制御を行うことで電圧均等化処理が可能な比較的小さな電圧差であるか否かの観点から設定される。 If the determination in S16 is affirmative, it is next determined whether or not ΔV is equal to or greater than a second predetermined voltage difference ΔV th2 that is set in advance (S18). The second predetermined voltage difference is a voltage difference that is larger than the error range and is set from the viewpoint of whether or not the voltage difference is a relatively small voltage difference that can be voltage-equalized by performing ON / OFF control of the five relays. To be done.

Ｓ１８が否定されるときは、ΔＶがごく小さい値であって、電圧均等化処理を行う必要がない場合であるので、電圧検出部４０，４６の電源をオフする（Ｓ２２）。そして、適当な待機時間の経過を待って（Ｓ２４）、再び電圧検出部４０，４６の電源をオンし（Ｓ２６）、Ｓ１４の手順に戻る。   When S18 is denied, ΔV is a very small value and it is not necessary to perform the voltage equalization process, so the power supplies of the voltage detection units 40 and 46 are turned off (S22). Then, after waiting an appropriate waiting time (S24), the power supplies of the voltage detectors 40 and 46 are turned on again (S26), and the procedure returns to S14.

Ｓ１８が肯定されるときは、ΔＶth1＞ΔＶ＞ΔＶth2であって、ΔＶが予め定めた所定値範囲内にある。この場合にＳ３０以下の電圧均等化処理が進められる。Ｓ３０とＳ３２は、第１の電圧均等化処理の手順である。第１の電圧均等化処理において、各リレーのオンオフ設定が以下のように行われる（Ｓ３０）。すなわち、一方側の電池スタック２２については、ＳＭＲ−Ｂ１はオフのままで、ＳＭＲ−Ｇ１とＳＭＲ−Ｐをオンする。他方側の電池スタック２４については、ＳＭＲ−Ｂ１とＳＭＲ−Ｇ１をオンする。 When S18 is positive, ΔV th1 >ΔV> ΔV th2 , and ΔV is within the predetermined value range. In this case, the voltage equalization process of S30 and below is advanced. S30 and S32 are the steps of the first voltage equalization processing. In the first voltage equalization process, the on / off setting of each relay is performed as follows (S30). That is, for the battery stack 22 on one side, the SMR-B1 remains off and the SMR-G1 and SMR-P are turned on. For the battery stack 24 on the other side, SMR-B1 and SMR-G1 are turned on.

図５は、第１の電圧均等化処理における電源装置２０の各リレーのオンオフを示す図である。ここでは、Ｖ１＞Ｖ２の例を示す。第１の電圧均等化処理においては、ＳＭＲ−Ｂ１はオフであるが、ＳＭＲ−Ｇ１とＳＭＲ−Ｇ１がオンするので、一方側の電池スタック２２から電流制限抵抗３５を通る電流が正極母線２６側に流れる。一方側の電池スタック２４においては、ＳＭＲ−Ｂ２，ＳＭＲ−Ｇ２がオンであるので、一方側の電池スタック２２から正極母線２６に流れてきた電流は、他方側の電池スタック２４に流れ込む。図５において、流れる電流を太線で示し、電流の方向を矢印で示す。すなわち、高い端子間電圧Ｖ１の状態の一方側の電池スタック２２から、低い端子間電圧Ｖ２の他方側の電池スタック２４に向かって電流が流れ、これにより、電圧差ΔＶ＝|Ｖ１−Ｖ２|を少なくする方向に電圧均等化が行われる。Ｖ１＜Ｖ２のときは、電流の方向が反対方向となる。   FIG. 5 is a diagram showing ON / OFF of each relay of the power supply device 20 in the first voltage equalization processing. Here, an example of V1> V2 is shown. In the first voltage equalization process, SMR-B1 is off, but SMR-G1 and SMR-G1 are on. Therefore, the current passing from the battery stack 22 on one side through the current limiting resistor 35 is on the positive electrode bus 26 side. Flow to. In the battery stack 24 on one side, the SMR-B2 and SMR-G2 are on, so the current flowing from the battery stack 22 on one side to the positive electrode bus 26 flows into the battery stack 24 on the other side. In FIG. 5, the flowing current is indicated by a thick line, and the direction of the current is indicated by an arrow. That is, a current flows from the battery stack 22 on one side in the state of the high terminal voltage V1 toward the battery stack 24 on the other side of the low terminal voltage V2, whereby the voltage difference ΔV = | V1-V2 | Voltage equalization is performed in the direction of decreasing the voltage. When V1 <V2, the directions of the currents are opposite.

第１の電圧均等化処理においてＳＭＲ−Ｐを用いることで、一方側の電池スタック２２の端子間電圧Ｖ１と他方側の電池スタック２４の端子間電圧Ｖ２の間の電圧差ΔＶのために流れる電流Ｉ２を電流制限抵抗３５で抑えることができる。これによって、ＳＭＲ−Ｇ１，ＳＭＲ−Ｂ２，ＳＭＲ−Ｇ２にΔＶによる過大な突入電流が流れることを防止し、リレーの溶着や耐久性低下等を防止できる。   By using SMR-P in the first voltage equalization process, the current flowing due to the voltage difference ΔV between the terminal voltage V1 of the battery stack 22 on the one side and the terminal voltage V2 of the battery stack 24 on the other side. I2 can be suppressed by the current limiting resistor 35. As a result, it is possible to prevent an excessive inrush current due to ΔV from flowing through the SMR-G1, SMR-B2, and SMR-G2, and to prevent welding of the relay and deterioration of durability.

なお、第１の電圧均等化処理においてＳＭＲ−Ｐを用いることは、電源装置２０の起動に先立って行われるプリチャージ処理に似ているが以下の相違点がある。プリチャージ処理の場合は、他方側の電池スタック２４のＳＭＲ−Ｂ２，ＳＭＲ−Ｇ２がオフであるが、第１の電圧均等化処理においては、他方側の電池スタック２４のＳＭＲ−Ｂ２，ＳＭＲ−Ｇ２がオンである。なお、電流制限抵抗３５によって制限された一方側の電池スタック２２からの電流は、一般的な電圧均等化処理で用いられる均等化電流と比較すると、１桁から２桁程度大きな電流である。したがって、一般的な電圧均等化方法に比較して、短時間で電圧均等化を実行することができる。   The use of SMR-P in the first voltage equalization processing is similar to the precharge processing performed prior to the activation of the power supply device 20, but has the following differences. In the case of the precharge process, SMR-B2 and SMR-G2 of the battery stack 24 on the other side are off, but in the first voltage equalization process, SMR-B2 and SMR- of the battery stack 24 on the other side are turned off. G2 is on. The current from the battery stack 22 on one side, which is limited by the current limiting resistor 35, is one to two orders of magnitude larger than the equalizing current used in the general voltage equalizing process. Therefore, the voltage equalization can be executed in a short time as compared with a general voltage equalization method.

Ｓ３０において、各リレーのオンオフ設定が行われると、その状態は、予め定めた所定時間の間、維持される（Ｓ３２）。予め定めた所定時間は、リレーの耐久性の観点から、次のようにして定める。まず、電池スタック２２，２４の端子間電圧Ｖ１，Ｖ２と、電池スタック２２，２４の内部抵抗と、電池スタック２２，２４の電池容量とに基づき、電圧差ΔＶ＝|Ｖ１−Ｖ２|がリレーの耐久性の観点から許容できる目標電圧差ΔＶ0になるまでの時間を求める。そして、求められた時間を所定時間とする。電池スタック２２，２４の内部抵抗は、電池温度θ１，θ２から概算でき、電池スタック２２，２４の電池容量は、予め定まっている値を用いることができる。 When the on / off setting of each relay is performed in S30, the state is maintained for a predetermined time that has been set in advance (S32). The predetermined time set in advance is determined as follows from the viewpoint of the durability of the relay. First, based on the inter-terminal voltages V1 and V2 of the battery stacks 22 and 24, the internal resistances of the battery stacks 22 and 24, and the battery capacities of the battery stacks 22 and 24, the voltage difference ΔV = | V1-V2 | From the viewpoint of durability, the time required to reach the allowable target voltage difference ΔV 0 is calculated. Then, the obtained time is set as a predetermined time. The internal resistance of the battery stacks 22 and 24 can be roughly estimated from the battery temperatures θ1 and θ2, and the battery capacities of the battery stacks 22 and 24 can be set to predetermined values.

所定時間に達したか否かの判定方法の１つは、電流の時間積分値と開放回路電圧ＯＣＶの変化量との関係を予め求めておき、初期の電圧差ΔＶからΔＶ0に下降するのに要する電流の時間積分値を求める。そして、時々刻々の電流Ｉ２を時間積分し、その実積分値が、求められた電流の時間積分値以上となる時間を所定時間とし、その時間に達すると、次のＳ３４に進む。もう１つの判定方法は、実験又はシミュレーション等で、初期の電圧差ΔＶからΔＶ0に下降するのに要する時間を予め求めて、これを所定時間とし、その時間に達すると、次のＳ３４に進む。 One of the methods for determining whether or not the predetermined time has been reached is to obtain the relationship between the time integrated value of the current and the amount of change in the open circuit voltage OCV in advance, and then decrease from the initial voltage difference ΔV to ΔV 0 . The time integral value of the current required for is calculated. Then, the current I2 is momentarily integrated, and the time when the actual integrated value is equal to or greater than the obtained time integrated value of the current is set as a predetermined time. When the time is reached, the process proceeds to the next S34. Another determination method is an experiment or a simulation or the like, in which the time required to decrease from the initial voltage difference ΔV to ΔV 0 is obtained in advance, and this is set as a predetermined time. When that time is reached, the process proceeds to the next S34. ..

第１の電圧均等化処理における目標電圧差ΔＶ0は、リレーの耐久性の観点から定められるが、一例を挙げると、電池スタック２２，２４の各端子間電圧の数％〜１％程度である。例えば、電池スタック２２，２４の各端子間電圧Ｖ１，Ｖ２を約２００Ｖとし、その２％が目標電圧差ΔＶ0となる場合では、目標電圧差ΔＶ0は約４Ｖ以下である。 The target voltage difference ΔV 0 in the first voltage equalization processing is determined from the viewpoint of the durability of the relay, but as an example, it is about several% to 1% of the voltage between the terminals of the battery stacks 22 and 24. .. For example, when the voltages V1 and V2 between the terminals of the battery stacks 22 and 24 are set to about 200 V, and 2% of them are the target voltage difference ΔV 0 , the target voltage difference ΔV 0 is about 4 V or less.

Ｓ３０の状態を所定時間維持すると、電池スタック２２，２４の端子間電圧の差である電圧差ΔＶは、目標電圧差ΔＶ0まで低減するので、電源装置２０の次の再起動のために、電源装置２０の動作停止状態に戻り、全リレーがオフとされ（Ｓ３４）。電圧均等化処理を終了する（Ｓ３６）。 If the state of S30 is maintained for a predetermined time, the voltage difference ΔV, which is the voltage difference between the terminals of the battery stacks 22 and 24, is reduced to the target voltage difference ΔV 0, so that the power supply device 20 is restarted for the next restart. The operation of the device 20 is returned to the stopped state, and all the relays are turned off (S34). The voltage equalization process ends (S36).

ここで、第１の電圧均等化処理は、電流制限抵抗３５を経由して電圧差ΔＶの低減が行われるので、電流制限抵抗３５における損失が発生し、エネルギを無駄に捨てていることになって、車両の燃費低下につながる。   Here, in the first voltage equalization process, the voltage difference ΔV is reduced via the current limiting resistor 35, so that loss occurs in the current limiting resistor 35, and energy is wasted. As a result, the fuel efficiency of the vehicle is reduced.

図６は、電流制限抵抗３５によるエネルギ損失なしで電圧差ΔＶを低減できる電源装置２０の各リレーのオンオフを示す図である。ここでは、Ｖ１＞Ｖ２の例を示す。この場合、ＳＭＲ−Ｐはオフであるが、ＳＭＲ−Ｂ１，ＳＭＲ−Ｇ１がオンであるので、一方側の電池スタック２２からの電流は電流制限抵抗３５を介さずに正極母線２６側に流れる。一方側の電池スタック２４においては、ＳＭＲ−Ｂ２，ＳＭＲ−Ｇ２がオンであるので、一方側の電池スタック２２から正極母線２６に流れてきた電流は、他方側の電池スタック２４に流れ込む。図６において、流れる電流を太線で示し、電流の方向を矢印で示す。図５と比較すると、流れる電流が電流制限抵抗３５を介さないので、電流制限抵抗３５によるエネルギ損失がない。また、電圧差ΔＶを低減するように流れる電流は、図５の場合に比較して大きい電流となるので、電圧差ΔＶ＝|Ｖ１−Ｖ２|は、図５における低減速度よりも速く、短時間で、電圧差ΔＶを低減できる。以下では、図６のオンオフ状態を用いる電圧均等化方法を、単に、図６を用いる方法と呼ぶ。   FIG. 6 is a diagram showing ON / OFF of each relay of the power supply device 20 capable of reducing the voltage difference ΔV without energy loss due to the current limiting resistor 35. Here, an example of V1> V2 is shown. In this case, the SMR-P is off, but the SMR-B1 and SMR-G1 are on, so that the current from the battery stack 22 on one side flows to the positive electrode bus 26 side without passing through the current limiting resistor 35. In the battery stack 24 on one side, the SMR-B2 and SMR-G2 are on, so the current flowing from the battery stack 22 on one side to the positive electrode bus 26 flows into the battery stack 24 on the other side. In FIG. 6, the flowing current is indicated by a thick line, and the direction of the current is indicated by an arrow. As compared with FIG. 5, since the flowing current does not pass through the current limiting resistor 35, there is no energy loss due to the current limiting resistor 35. Further, the current that flows so as to reduce the voltage difference ΔV is a larger current than that in the case of FIG. 5, so the voltage difference ΔV = | V1-V2 | is faster than the reduction speed in FIG. Thus, the voltage difference ΔV can be reduced. Hereinafter, the voltage equalization method using the on / off state of FIG. 6 will be simply referred to as the method using FIG.

しかし、図６を用いる方法においては、電池スタック２２，２４に通電するので、電池スタック２２，２４の自己発熱量が増大する。これにより電池温度θ１，θ２が上昇し、電池スタック２２，２４の早期劣化を生じやすくなる。これを防止するために電池スタック２２，２４について冷却手段を設け、これを駆動させることが考えられるが、ブロワや冷却器等の冷却手段を駆動させると、却って、車両の燃費低下や航続距離低下を招く恐れがある。そこで、図６の各リレーの設定を用いて電圧均等化処理を実行するに当たっては、電池温度θ１，θ２の上昇を考慮することが好ましい。   However, in the method using FIG. 6, since the battery stacks 22 and 24 are energized, the amount of self-heating of the battery stacks 22 and 24 increases. As a result, the battery temperatures θ1 and θ2 rise, and the battery stacks 22 and 24 are likely to deteriorate early. In order to prevent this, it is conceivable to provide a cooling means for the battery stacks 22 and 24 and drive the cooling means. However, if the cooling means such as a blower or a cooler is driven, the fuel consumption of the vehicle and the cruising range are reduced. May lead to Therefore, when executing the voltage equalization process using the settings of the respective relays in FIG. 6, it is preferable to consider the increase in the battery temperatures θ1 and θ2.

図７は、電流制限抵抗３５による損失を最小限にしながら、電池温度θ１，θ２の上昇も考慮に入れた第２の電圧均等化処理の手順を示すフローチャートである。第２の電圧均等化処理は、第１の電圧均等化処理におけるＳ３０までの手順を前提として、電圧差ΔＶが目標電圧差ΔＶ0まで低減した状態から行う。そして、図６を用いる方法によって、電流制限抵抗３５によるエネルギ損失なしで、目標電圧差ΔＶ0をさらに低減して、例えば、ΔＶを、電池スタック２２，２４の各端子間電圧の１％程度以下とする。 FIG. 7 is a flowchart showing the procedure of the second voltage equalization processing in which the increase in the battery temperatures θ1 and θ2 is taken into consideration while minimizing the loss due to the current limiting resistance 35. The second voltage equalization process is performed from the state where the voltage difference ΔV is reduced to the target voltage difference ΔV 0 on the premise of the procedure up to S30 in the first voltage equalization process. By the method using FIG. 6, the target voltage difference ΔV 0 is further reduced without energy loss due to the current limiting resistor 35, and ΔV is, for example, about 1% or less of the voltage between terminals of the battery stacks 22 and 24. And

図７において、図２のフローチャートと相違する処理は太枠で囲み、図２のフローチャートと相違する処理の流れは矢印付き太線で示す。Ｓ２０以前の処理は、図２のフローチャートで述べた内容と同じであるので、これらの詳細な説明を省略する。Ｓ２０の判定が肯定されると、図２ではＳ３０の第１の電圧均等化処理に進むが、図７では、Ｓ２０の判定が肯定されると、電池温度θ１，θ２の取得が行われる（Ｓ４０）。そして、Ｓ３０，Ｓ３２の第１の電圧均等化処理を実行し、その後に、再度、電池温度θ１，θ２の取得が行われる（Ｓ４２）。Ｓ４２，Ｓ４４と２回に分けて電池温度θ１，θ２の取得を行うのは、電池温度θ１，θ２を慎重に考慮するためである。電池温度θ１，θ２の取得は、電池温度検出部４４，５０から伝送されてくる検出データを電池制御部６０が取得することで実行される。   In FIG. 7, processes different from those in the flowchart of FIG. 2 are surrounded by thick frames, and flows of processes different from those in the flowchart of FIG. 2 are indicated by thick lines with arrows. Since the processing before S20 is the same as the content described in the flowchart of FIG. 2, detailed description thereof will be omitted. If the determination in S20 is affirmative, the process proceeds to the first voltage equalization process in S30 in FIG. 2, but in FIG. 7, if the determination in S20 is affirmative, the battery temperatures θ1 and θ2 are acquired (S40). ). Then, the first voltage equalization processing in S30 and S32 is executed, and thereafter, the battery temperatures θ1 and θ2 are acquired again (S42). The reason why the battery temperatures θ1 and θ2 are acquired separately in two steps S42 and S44 is to carefully consider the battery temperatures θ1 and θ2. The battery temperatures θ1 and θ2 are acquired by the battery control unit 60 acquiring the detection data transmitted from the battery temperature detection units 44 and 50.

次に、電池温度θ１，θ２のいずれか高い方の電池温度が予め定めた所定温度θth以下であるか否かが判定される。これを言い換えると、電池温度θ１及び電池温度θ２のいずれもが所定温度θth以下であるか否かが判定される（Ｓ４４）。所定温度θthは、図６を用いる方法を実行すると上昇する電池温度を予め実験やシミュレーションで見積っておき、その見積られた温度上昇があっても、電池冷却手段を駆動しなくて済む温度である。 Next, it is determined whether the higher battery temperature of the battery temperatures θ1 and θ2 is equal to or lower than a predetermined temperature θ th . In other words, it is determined whether or not both the battery temperature θ1 and the battery temperature θ2 are below the predetermined temperature θ th (S44). The predetermined temperature θ th is a temperature at which the battery temperature that rises when the method of FIG. 6 is executed is estimated in advance by experiments or simulations, and the battery cooling means does not have to be driven even if the estimated temperature rises. is there.

Ｓ４４の判定が肯定されると、図６を用いる方法を実行しても電池冷却手段を駆動させることがないので、Ｓ４８に進む。Ｓ４８では、図６で述べた内容に従って、各リレーのオンオフ設定が以下のように行われる。すなわち、第１の電圧均等化処理において、オンであったＳＭＲ−Ｐをオフし、オフであったＳＭＲ−Ｂ１をオンする。すなわち、一方側の電池スタック２２については、ＳＭＲ−Ｂ１，ＳＭＲ−Ｇ１がオンで、ＳＭＲ−Ｐはオフである。他方側の電池スタック２４については、ＳＭＲ−Ｂ１，ＳＭＲ−Ｇ１はオンのままである。   If the determination in S44 is affirmative, the battery cooling means is not driven even if the method using FIG. 6 is executed, so the process proceeds to S48. In S48, the on / off setting of each relay is performed as follows according to the contents described in FIG. That is, in the first voltage equalization processing, the SMR-P that was on is turned off, and the SMR-B1 that was off is turned on. That is, for the battery stack 22 on one side, SMR-B1 and SMR-G1 are on and SMR-P is off. Regarding the battery stack 24 on the other side, SMR-B1 and SMR-G1 remain ON.

Ｓ４８の実行によって、電圧差ΔＶがさらに低減する。例えば、目標電圧差ΔＶ0が電池スタック２２，２４の各端子間電圧の１％程度以下となれば、電圧均等化は十分に行われているので、Ｓ３４、Ｓ３６に進む。Ｓ３４、Ｓ３６の内容は、図２で述べたので、詳細な説明を省略する。 By executing S48, the voltage difference ΔV is further reduced. For example, if the target voltage difference ΔV 0 is about 1% or less of the voltage between the terminals of the battery stacks 22 and 24, the voltage equalization is sufficiently performed, and the process proceeds to S34 and S36. Since the contents of S34 and S36 have been described in FIG. 2, detailed description thereof will be omitted.

Ｓ４４の判定が否定されるときは、その状態で図６を用いる方法を実行すると電池冷却手段を駆動する可能性が高いので、Ｓ３０の状態をそのまま維持し（Ｓ４８）、電池温度θ１，θ２の推移を監視する。監視時間は数ｓから１０ｓ程度である。監視時間が経過すると、電池温度θ１及び電池温度θ２のいずれもが所定温度θth以下であるか否かが判定される（Ｓ５０）。Ｓ５０の内容はＳ４４と同じであるので、詳細な説明を省略する。Ｓ５０の判定が肯定されると、Ｓ４６，Ｓ３４，Ｓ３６に進む。Ｓ５０の判定が否定されると、図６を用いる方法が実行できないので、目標電圧差ΔＶ0をさらに低減せずに、電源装置２０の動作停止状態に戻り、全リレーがオフとされるＳ３４に進む。そして、図７の第２の電圧均等化処理が終了する（Ｓ３６）。 If the determination in S44 is negative, the battery cooling means is likely to be driven if the method using FIG. 6 is executed in that state, so the state in S30 is maintained as it is (S48) and the battery temperatures θ1 and θ2 are changed. Monitor the transition. The monitoring time is about several seconds to 10 seconds. When the monitoring time has elapsed, it is determined whether or not both the battery temperature θ1 and the battery temperature θ2 are equal to or lower than the predetermined temperature θ th (S50). Since the contents of S50 are the same as S44, detailed description will be omitted. If the determination in S50 is affirmative, the process proceeds to S46, S34, and S36. If the determination in S50 is negative, the method using FIG. 6 cannot be executed. Therefore, the target voltage difference ΔV 0 is not further reduced, the power supply device 20 returns to the operation stop state, and all relays are turned off in S34. move on. Then, the second voltage equalization process of FIG. 7 ends (S36).

なお、図６を用いる方法における各リレーのオンオフ設定の状態は、図３の電源装置２０が動作中のときの各リレーのオンオフ設定の状態と同じである。異なるのは、電源装置２０が動作中のときのＶ１，Ｖ２はＣＣＶであるので、並列接続された電池スタック２２，２４の各開放回路電圧ＯＣＶではなく、したがって、開放回路電圧ＯＣＶの電圧差ΔＶが現れないことである。電源装置２０が図６を用いる方法によって第２の電圧均等化処理を実行するときは、開放回路電圧ＯＣＶの電圧差ΔＶが現れ、一方側の電池スタック２２と他方側の電池スタック２４との間にΔＶを低減する電流が流れて、電圧均等化が行われる。   The ON / OFF setting state of each relay in the method using FIG. 6 is the same as the ON / OFF setting state of each relay when the power supply device 20 in FIG. 3 is operating. The difference is that V1 and V2 when the power supply device 20 is in operation are CCV, and therefore not the open circuit voltage OCV of the battery stacks 22 and 24 connected in parallel, and therefore the voltage difference ΔV of the open circuit voltage OCV. Does not appear. When the power supply device 20 executes the second voltage equalization process by the method using FIG. 6, a voltage difference ΔV of the open circuit voltage OCV appears, and the voltage difference between the battery stack 22 on one side and the battery stack 24 on the other side appears. A current that reduces ΔV flows to the device, and voltage equalization is performed.

本実施の形態における電池スタックの電圧均等化方法は、正極母線２６と正極側リレーに接続される正極、及び、負極母線２８と負極側リレーに接続される負極を有する電池スタック２２，２４を２つ並列接続した電源装置２０に関する。電源装置２０は、さらに、電流制限抵抗３５を直列接続したプリチャージリレー３４を一方側の電池スタックの正極側リレーにのみ並列に接続して構成されて、プリチャージリレー３４以外をすべてオンして起動する。そして、全てのリレーをオフして動作を停止する。電源装置２０における電池スタックの電圧均等化方法は、電源装置２０の動作の停止後において（Ｓ１２）、異なる電池スタック２２，２４間の電圧差ΔＶが均等化処理を許可できる所定値範囲内であるか否かを判定する（Ｓ１６、Ｓ２０）。所定値範囲内の場合には、一方側の電池スタックの正極側リレーをオフのままプリチャージリレー３４と負極側リレーとをオンし、かつ、他方側の電池スタックの正極側リレーと負極側リレーを共にオンする（Ｓ３０）。そして、電池スタック２２，２４の間の電圧差ΔＶが所定の電圧差に低減するまでの所定時間はその状態を維持する（Ｓ３２）。   The voltage equalizing method of the battery stack according to the present embodiment includes two battery stacks 22 and 24 each having a positive electrode bus 26 and a positive electrode connected to a positive electrode side relay, and a negative electrode bus line 28 and a negative electrode connected to a negative electrode side relay. One power supply device 20 connected in parallel. The power supply device 20 further includes a precharge relay 34 in which a current limiting resistor 35 is connected in series and is connected in parallel only to a positive electrode side relay of a battery stack on one side, and turns on all except the precharge relay 34. to start. Then, all the relays are turned off to stop the operation. In the method of equalizing the voltage of the battery stack in the power supply device 20, after the operation of the power supply device 20 is stopped (S12), the voltage difference ΔV between the different battery stacks 22 and 24 is within a predetermined value range that allows the equalization process. It is determined whether or not (S16, S20). If it is within the predetermined value range, the precharge relay 34 and the negative electrode side relay are turned on while the positive electrode side relay of the one side battery stack is turned off, and the positive electrode side relay and the negative side relay of the other side battery stack are turned on. Are turned on together (S30). Then, the state is maintained for a predetermined time until the voltage difference ΔV between the battery stacks 22 and 24 is reduced to a predetermined voltage difference (S32).

１０ 車両駆動システム、１２ 回転電機、１３ 駆動回路、１４ インバータ、１６ 平滑コンデンサ、１８ ＤＣ／ＤＣコンバータ、２０ 電源装置、２２，２４ 電池スタック、２６ 正極母線、２８ 負極母線、３０，３６ ＳＭＲ−Ｂ（正極側リレー）、３２，３８ ＳＭＲ−Ｇ（負極側リレー）、３４ ＳＭＲ−Ｐ（プリチャージリレー）、３５ 電流制限抵抗、４０，４６ 電圧検出部、４２，４８ 電流検出部、４４，５０ 電池温度検出部、５８ 起動／停止指令、６０ 電池制御部。   10 vehicle drive system, 12 rotary electric machine, 13 drive circuit, 14 inverter, 16 smoothing capacitor, 18 DC / DC converter, 20 power supply device, 22, 24 battery stack, 26 positive bus, 28 negative bus, 30, 36 SMR-B (Positive side relay), 32,38 SMR-G (negative side relay), 34 SMR-P (precharge relay), 35 current limiting resistor, 40,46 voltage detection unit, 42,48 current detection unit, 44,50 Battery temperature detection unit, 58 start / stop command, 60 battery control unit.

Claims (1)

正極母線と正極側リレーに接続される正極、及び、負極母線と負極側リレーに接続される負極を有する電池スタックを２つ並列接続し、電流制限抵抗を直列接続したプリチャージリレーを一方側の前記電池スタックの前記正極側リレーにのみ並列に接続して構成されて、前記プリチャージリレー以外をすべてオンして起動し、全てのリレーをオフして動作を停止する電源装置における前記電池スタックの電圧均等化方法であって、
前記電源装置の前記動作の停止後において、異なる前記電池スタック間の電圧差が均等化処理を許可できる所定値範囲内であるか否かを判定し、
前記所定値範囲内の場合には、前記一方側の電池スタックの前記正極側リレーをオフのまま前記プリチャージリレーと前記負極側リレーとをオンし、かつ、他方側の前記電池スタックの前記正極側リレーと前記負極側リレーを共にオンし、前記電池スタックの間の電圧差が所定の電圧差に低減するまでの所定時間はその状態を維持する、複数の電池スタックの電圧均等化方法。 A precharge relay in which two battery stacks each having a positive electrode bus connected to a positive electrode side relay and a negative electrode bus and a negative electrode connected to a negative electrode side relay are connected in parallel and a current limiting resistor is connected in series are provided on one side. The battery stack is configured to be connected in parallel only to the positive electrode side relays of the battery stack, and all but the precharge relays are turned on to start, and all relays are turned off to stop the operation of the battery stack. A voltage equalization method,
After stopping the operation of the power supply device, it is determined whether the voltage difference between the different battery stacks is within a predetermined value range that allows the equalization process,
In the case of being within the predetermined value range, the precharge relay and the negative electrode side relay are turned on while the positive electrode side relay of the battery stack on the one side is turned off, and the positive electrode of the battery stack on the other side is turned on. A voltage equalization method for a plurality of battery stacks, wherein both side relays and the negative side relay are turned on and the state is maintained for a predetermined time until the voltage difference between the battery stacks is reduced to a predetermined voltage difference.
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