JP4533357B2

JP4533357B2 - Voltage measuring device

Info

Publication number: JP4533357B2
Application number: JP2006240979A
Authority: JP
Inventors: 彰彦工藤; 正樹長岡; 昭彦江守
Original assignee: Hitachi Vehicle Energy Ltd
Current assignee: Vehicle Energy Japan Inc
Priority date: 2006-09-06
Filing date: 2006-09-06
Publication date: 2010-09-01
Anticipated expiration: 2026-09-06
Also published as: JP2008064520A

Description

本発明は電圧測定装置に係り、特に、単電池が直列に接続された電池群の各単電池の＋端子を選択する第１のマルチプレクサと各単電池の−端子を選択する第２のマルチプレクサとを用いて各単電池の＋端子と−端子とをそれぞれ差動増幅器の＋入力端子および−入力端子に接続し、差動増幅器の出力電圧を検出することで各単電池の電圧を測定する電圧測定装置に関する。 The present invention relates to a voltage measuring device, and in particular, a first multiplexer that selects the + terminal of each unit cell of a battery group in which unit cells are connected in series, and a second multiplexer that selects the-terminal of each unit cell. Is used to connect the + terminal and − terminal of each cell to the + input terminal and − input terminal of the differential amplifier, respectively, and to measure the voltage of each cell by detecting the output voltage of the differential amplifier. It relates to a measuring device.

従来、複数の単電池が直列に接続された組電池（電池群）用の制御回路として、組電池を構成する各単電池の電圧を計測して制御する方式が用いられている（例えば、特許文献１、２参照）。組電池を構成する各単電池の電圧を測定するのは、安全性に影響を及ぼす過充電状態を確実に検出するためと、単電池電圧のバラツキをなくして組電池全体の寿命と入出力特性とを最大限に引き出すためである。また、安全性に影響を及ぼす過充電状態を確実に検出するために、単電池電圧の検出回路を二組設け、過充電状態の検出のみは別の系統で検出する制御回路が用いられている。図２にその構成例を示す。 Conventionally, as a control circuit for an assembled battery (battery group) in which a plurality of single cells are connected in series, a method of measuring and controlling the voltage of each single cell constituting the assembled battery has been used (for example, a patent) References 1 and 2). The voltage of each unit cell constituting the assembled battery is measured in order to reliably detect the overcharged state that affects safety, and to eliminate the variation of the unit cell voltage, and the life and input / output characteristics of the entire assembled battery. It is for drawing out to the maximum. In addition, in order to reliably detect an overcharged state that affects safety, two sets of single battery voltage detection circuits are provided, and a control circuit that detects only the overcharged state by another system is used. . FIG. 2 shows an example of the configuration.

図２に示すように、単電池が４直列に接続された組電池１の単電池端子が、＋端子を切り替えるマルチプレクサ２と−端子を切り替えるマルチプレクサ３の入力に接続され、マルチプレクサ２とマルチプレクサ３の出力は差動増幅器４の入力に接続される。差動増幅器4の出力はマイコン５のＡＤコンバータ入力に接続されており、マイコン５はマルチプレクサ２とマルチプレクサ３の入力切替端子を制御出力して、単電池の電圧を測定する。マイコン５は単電池電圧が過充電電圧に達してれば過充電状態と判断し、上位の制御システムへ信号を送出する。また、差動増幅器５−１から差動増幅器５−４は、各々の単電池の端子を入力とし、出力は比較電圧が過充電検電圧と同じ電圧源８の過充電検出用のコンパレータ６−１から６−４の入力となる。コンパレータ６の出力はＯＲ回路７を経由して過充電信号の出力となり、上位の制御システムに信号が送出される。 As shown in FIG. 2, the unit cell terminals of the assembled battery 1 in which four unit cells are connected in series are connected to the input of the multiplexer 2 that switches the + terminal and the multiplexer 3 that switches the − terminal. The output is connected to the input of the differential amplifier 4. The output of the differential amplifier 4 is connected to the AD converter input of the microcomputer 5, and the microcomputer 5 controls and outputs the input switching terminals of the multiplexer 2 and the multiplexer 3 to measure the voltage of the unit cell. If the single battery voltage reaches the overcharge voltage, the microcomputer 5 determines that it is in an overcharge state, and sends a signal to the host control system. The differential amplifier 5-1 to the differential amplifier 5-4 receive the terminal of each unit cell as an input, and the output is a comparator 6 for detecting overcharge of the voltage source 8 having the same comparison voltage as the overcharge detection voltage. Input from 1 to 6-4. The output of the comparator 6 becomes an output of an overcharge signal via the OR circuit 7, and a signal is sent to the host control system.

図２に示す電圧測定装置では、単電池の過充電検出系が二系統あるので、どちらかの過充電検出系が故障しても、安全性に影響を及ぼす過充電状態を検出できるようになっている。 In the voltage measuring apparatus shown in FIG. 2, since there are two overcharge detection systems for a single cell, even if one of the overcharge detection systems breaks down, an overcharge state that affects safety can be detected. ing.

特開２００３−２８２１５７号公報JP 2003-282157 A 特開２００５−１０６５０４号公報Japanese Patent Laying-Open No. 2005-106504

ところが、従来の電圧測定装置では、単電池の電圧検出系を二系統必要とするため、コスト高となり、回路規模も大きくなる、という課題を有している。単電池の電圧検出系を一系統にした場合、マルチプレクサ、差動増幅器、ＡＤコンバータのいずれかが故障した場合は、単電池電圧を誤って測定するため過充電状態での安全性を確保できないおそれがある。この構成要素の中で、差動増幅器とＡＤコンバータは、ＡＤコンバータとは別の基準電圧を測定することで、正常に動作しているかどうか診断することが可能であるが、マルチプレクサが故障した場合、特に単電池の入力選択が制御できない故障の場合には、単電池電圧の検出が不可能となり、過充電状態を検出できないことになる。 However, since the conventional voltage measuring device requires two voltage detection systems for single cells, there is a problem that the cost is increased and the circuit scale is increased. When the voltage detection system of a single cell is integrated into one system, if any of the multiplexer, differential amplifier, or AD converter fails, the single cell voltage may be measured incorrectly, which may prevent safety in an overcharged state. There is. Among these components, it is possible to diagnose whether the differential amplifier and the AD converter are operating normally by measuring a reference voltage different from that of the AD converter. In particular, in the case of a failure in which the input selection of the unit cell cannot be controlled, the unit cell voltage cannot be detected, and the overcharge state cannot be detected.

本発明は上記事案に鑑み、単電池の電圧検出系を二系統用いずに、単電池電圧の検出が正常に切り替わっていることを検出できる電圧測定装置を提供することを課題とする。 An object of the present invention is to provide a voltage measuring device capable of detecting that the detection of the cell voltage is normally switched without using two cell voltage detection systems.

上記課題を解決するために、本発明の第１の態様は、単電池が直列に接続された電池群の各単電池の＋端子を選択する第１のマルチプレクサと各単電池の−端子を選択する第２のマルチプレクサとを用いて前記各単電池の＋端子と−端子とをそれぞれ差動増幅器の＋入力端子および−入力端子に接続し、前記差動増幅器の出力電圧をＡＤコンバータを介して検出することで前記各単電池の電圧を測定する電圧測定装置において、前記第１のマルチプレクサで前記電池群を構成する最下位の単電池の＋端子、前記第２のマルチプレクサで前記最下位の単電池の−端子を選択して電圧を測定し、前記第１のマルチプレクサで前記最下位の単電池より一つ上位の単電池の＋端子、前記第２のマルチプレクサで前記最下位の単電池の−端子を選択して電圧を測定し、前記第１のマルチプレクサで前記一つ上位の単電池の＋端子、前記第２のマルチプレクサで前記一つ上位の単電池の−端子を選択して電圧を測定することで、前記第１および第２のマルチプレクサをそれぞれ最下位の単電池から最上位より一つ下位の単電池まで順番に上位側に切りかえて電圧を測定し、前記第１のマルチプレクサで前記最上位の単電池の＋端子、前記第２のマルチプレクサで前記最上位の単電池より一つ下位の単電池の−端子を選択して電圧を測定し、前記第１のマルチプレクサで前記最上位の単電池の＋端子、前記第２のマルチプレクサで前記最上位の単電池の−端子を選択して電圧を測定し、前記第１のマルチプレクサで前記最下位の単電池の＋端子、前記第２のマルチプレクサで前記最上位の単電池の−端子を選択して電圧を測定することで、測定対象となる単電池を順番に切り替える場合に、前記第１および第２のマルチプレクサを同時に切り替えないで前記＋端子のみ切り替えた状態と前記−端子のみを切り替えた状態とでも電圧を測定し、上記測定した電圧を比較して装置の診断を行う、ことを特徴とする。また、本発明の第２の態様は、単電池が直列に接続された電池群の各単電池の＋端子を選択する第１のマルチプレクサと各単電池の−端子を選択する第２のマルチプレクサとを用いて前記各単電池の＋端子と−端子とをそれぞれ差動増幅器の＋入力端子および−入力端子に接続し、前記差動増幅器の出力電圧をＡＤコンバータを介して検出することで前記各単電池の電圧を測定する電圧測定装置において、前記第１のマルチプレクサで前記電池群を構成する最下位の単電池の＋端子、前記第２のマルチプレクサで前記最下位の単電池の−端子を選択して電圧を測定し、前記第１のマルチプレクサで前記最下位の単電池の＋端子、前記第２のマルチプレクサで前記最下位の単電池より一つ上位の単電池の−端子を選択して電圧を測定し、前記第１のマルチプレクサで前記一つ上位の単電池の＋端子、前記第２のマルチプレクサで前記一つ上位の単電池の−端子を選択して電圧を測定することで、前記第１および第２のマルチプレクサをそれぞれ最下位の単電池から最上位より一つ下位の単電池まで順番に上位側に切りかえて電圧を測定し、前記第１のマルチプレクサで前記最上位より一つ下位の単電池の＋端子、前記第２のマルチプレクサで前記最上位の単電池の−端子を選択して電圧を測定し、前記第１のマルチプレクサで前記最上位の単電池の＋端子、前記第２のマルチプレクサで前記最上位の単電池の−端子を選択して電圧を測定し、前記第１のマルチプレクサで前記最上位の単電池の＋端子、前記第２のマルチプレクサで前記最下位の単電池の−端子を選択して電圧を測定することで、測定対象となる単電池を順番に切り替える場合に、前記第１および第２のマルチプレクサを同時に切り替えないで前記＋端子のみ切り替えた状態と前記−端子のみを切り替えた状態とでも電圧を測定し、上記測定した電圧を比較して装置の診断を行う、ことを特徴とする。 In order to solve the above-described problem, the first aspect of the present invention selects a first multiplexer that selects the + terminal of each unit cell in the battery group in which the unit cells are connected in series and the − terminal of each unit cell. A positive multiplexer and a negative terminal of each unit cell are connected to a positive input terminal and a negative input terminal of the differential amplifier, respectively, and an output voltage of the differential amplifier is passed through an AD converter. In the voltage measuring device for measuring the voltage of each unit cell by detecting the positive terminal of the lowest unit cell constituting the battery group by the first multiplexer, and the lowest unit unit by the second multiplexer. The voltage is measured by selecting the negative terminal of the battery, the positive terminal of the unit cell one higher than the lowest unit cell in the first multiplexer, and the negative unit cell of the lowest unit in the second multiplexer. Select the terminal Measuring the voltage by measuring the voltage by selecting the + terminal of the one higher cell in the first multiplexer and the-terminal of the one higher cell in the second multiplexer, The first and second multiplexers are respectively switched from the lowest cell to the upper cell in order from the highest cell to measure the voltage, and the first multiplexer is used to measure the voltage of the highest cell. A positive terminal, and the second multiplexer selects the negative terminal of the cell that is one level lower than the highest cell, and measures the voltage, and the first multiplexer uses the positive terminal of the highest cell, The second multiplexer selects the-terminal of the highest cell, and measures the voltage. The first multiplexer uses the lowest cell + terminal, and the second multiplexer uses the highest cell. Single cell By measuring the voltage selects the terminal, be measured when the unit cells may exchange cut sequentially, the first and second of said not switch simultaneously multiplexer + terminal only switched with said - The voltage is measured even when only the terminals are switched, and the apparatus is diagnosed by comparing the measured voltages . Moreover, the 2nd aspect of this invention is the 1st multiplexer which selects the + terminal of each cell of the battery group in which the cells were connected in series, and the second multiplexer which selects the-terminal of each cell. Are connected to the + input terminal and the − input terminal of the differential amplifier, respectively, and the output voltage of the differential amplifier is detected via an AD converter. In the voltage measuring apparatus for measuring the voltage of a single cell, the + terminal of the lowest cell constituting the battery group is selected by the first multiplexer, and the-terminal of the lowest cell is selected by the second multiplexer. Then, the voltage is measured, the positive terminal of the lowest cell is selected by the first multiplexer, and the negative terminal of the upper cell is selected by the second multiplexer. Measure the first The first multiplexer and the second multiplexer are measured by selecting the + terminal of the upper cell in the multiplexer and the-terminal of the upper cell in the second multiplexer and measuring the voltage. The voltage is measured by switching from the lowest cell to the upper cell one by one in order from the highest cell, and the + terminal of the single cell lower than the highest cell by the first multiplexer, The second multiplexer selects the-terminal of the top cell, and measures the voltage. The first multiplexer uses the top terminal + terminal, and the second multiplexer uses the top cell. The voltage is measured by selecting the-terminal of the battery, and the voltage is measured by selecting the + terminal of the highest cell in the first multiplexer and the-terminal of the lowest cell in the second multiplexer. Measure Thus, when the cells to be measured are sequentially switched, the voltage is measured even when only the + terminal is switched and only the − terminal is switched without switching the first and second multiplexers at the same time. Then, the apparatus is diagnosed by comparing the measured voltages.

本発明では、単電池の電圧検出の入力切替時に、マルチプレクサの＋入力端子と−入力端子を同時に切り替えるのではなく＋端子のみ切り替えた状態と−端子のみを切り替えた状態とでも差動増幅器の出力電圧を検出している。切り替える単電池の電池電圧が０Ｖでないかぎり、＋端子か−端子のどちらかの入力端子を切り替えれば、差動増幅の出力電圧は変わるため、切り替えた状態で差動増幅の出力電圧を検出して比較すれば、マルチプレクサが正常に切り替わっているかどうかを診断することができる。従って、本発明によれば、単電池の電圧検出系を二系統用いずに、単電池電圧の検出が正常に切り替わっていることを検出できる電圧測定装置を得ることができる。 In the present invention, when switching the voltage detection input of the unit cell, the output of the differential amplifier is not switched between the + input terminal and the −input terminal of the multiplexer at the same time but in the state where only the + terminal is switched and the state where only the −terminal is switched. The voltage is detected. Unless the battery voltage of the unit cell to be switched is 0V, if the input terminal of either the + terminal or the-terminal is switched, the output voltage of the differential amplification changes. Therefore, the output voltage of the differential amplification is detected in the switched state. By comparing, it is possible to diagnose whether the multiplexer has been switched normally. Therefore, according to the present invention, it is possible to obtain a voltage measuring device that can detect that the detection of the cell voltage is normally switched without using two cell voltage detection systems.

本発明において、＋端子と−端子との両方を切り替える前の測定電圧の値と＋端子と−端子との両方を切り替えた場合の測定電圧の値とが０Ｖでなく、かつ、＋端子と−端子との両方を切り替える前の測定電圧ないし＋端子と−端子との両方を切り替えた場合の測定電圧の値が同一または予め定められた設定範囲内の場合には、単電池の電圧が０Ｖであれば、＋入力端子か−入力端子を切り替えても差動増幅の出力電圧が変化しない可能性があるが、単電池の電圧が０Ｖでなければ、差動増幅器の＋入力と−入力のどちらかの入力端子を切り替えれば必ず差動増幅器の出力電圧が変化するため、マルチプレクサの切り替えが異常であり装置故障と診断することができる。このとき、上位の制御システムに信号を送出するようにしてもよい。 In the present invention, the value of the measured voltage before switching both the + terminal and the − terminal and the value of the measured voltage when switching both the + terminal and the − terminal are not 0 V, and the + terminal and − If the measured voltage before switching both terminals or the measured voltage when switching both + and-terminals is the same or within a predetermined setting range, the cell voltage is 0V. If there is, there is a possibility that the output voltage of the differential amplification does not change even if the + input terminal or the − input terminal is switched, but if the voltage of the unit cell is not 0 V, either the + input or the − input of the differential amplifier When the input terminal is switched, the output voltage of the differential amplifier always changes, so that the switching of the multiplexer is abnormal and it is possible to diagnose a device failure. At this time, a signal may be sent to the upper control system.

本発明によれば、単電池の電圧検出の入力切替時に、マルチプレクサの＋入力端子と−入力端子を同時に切り替えるのではなく＋端子のみ切り替えた状態と−端子のみを切り替えた状態とでも差動増幅器の出力電圧を検出しているので、＋端子か−端子のどちらかの入力端子を切り替えることで差動増幅の出力電圧は変わるため、切り替えた状態で差動増幅の出力電圧を検出して比較すれば、マルチプレクサが正常に切り替わっているかどうかを診断することができる、という効果を得ることができる。 According to the present invention, at the time of switching the voltage detection input of a single cell, the differential amplifier does not switch the + input terminal and the −input terminal of the multiplexer at the same time but switches only the + terminal and only the −terminal. Since the output voltage of differential amplification changes by switching either the + terminal or the-terminal, the differential amplification output voltage is detected and compared in the switched state. Then, it is possible to obtain an effect that it is possible to diagnose whether or not the multiplexer is normally switched.

以下、図面を参照して、本発明を、電気自動車の電源となる電池モジュールを構成する各単電池の電池電圧を測定する電圧測定装置に適用した実施の形態について説明する。 Hereinafter, an embodiment in which the present invention is applied to a voltage measuring device that measures a battery voltage of each unit cell constituting a battery module serving as a power source of an electric vehicle will be described with reference to the drawings.

（構成）
電池モジュールは、複数個の組電池１を直列接続することで所定電圧が確保されている。図１に示すように、組電池１（電池群）は４直列の単電池で構成されている。本実施形態では、組電池１を構成する各単電池にリチウムイオン二次電池が用いられている。 (Constitution)
The battery module has a predetermined voltage secured by connecting a plurality of assembled batteries 1 in series. As shown in FIG. 1, the assembled battery 1 (battery group) is composed of four series cells. In this embodiment, a lithium ion secondary battery is used for each single battery constituting the assembled battery 1.

本実施形態の電圧測定装置１０は、マルチプレクサ２、３、差動増幅器４、マイクロコンピュータ（以下、マイコンという。）５を有して構成されている。すなわち、組電池１を構成する各単電池の＋端子はマルチプレクサ２（第１のマルチプレクサ）の入力端子に接続されており、各単電池の−端子はマルチプレクサ３（第２のマルチプレクサ）の入力端子に接続されている。マルチプレクサ２、３の出力端子は、それぞれ、差動増幅器４の＋入力端子（正相入力端子）、−入力端子（逆相入力端子）に接続されている。なお、本実施形態では、差動増幅器４がＯＰアンプと複数の抵抗とで構成されている。 A voltage measuring apparatus 10 according to the present embodiment includes multiplexers 2 and 3, a differential amplifier 4, and a microcomputer (hereinafter referred to as a microcomputer) 5. That is, the + terminal of each cell constituting the assembled battery 1 is connected to the input terminal of the multiplexer 2 (first multiplexer), and the − terminal of each cell is the input terminal of the multiplexer 3 (second multiplexer). It is connected to the. The output terminals of the multiplexers 2 and 3 are connected to the + input terminal (positive phase input terminal) and the − input terminal (reverse phase input terminal) of the differential amplifier 4, respectively. In the present embodiment, the differential amplifier 4 includes an OP amplifier and a plurality of resistors.

また、マルチプレクサ２、３は、それぞれ単電池切替出力線でマイコン５の出力ポートに接続されている。マイコン５には不図示のＡＤコンバータが内蔵されており、差動増幅器４の出力端子はマイコン５のＡＤ入力端子（ＡＤコンバータの入力端子）に接続されている。このため、マイコン５は出力ポートを介してマルチプレクサ２、３に信号を送出することで、組電池１を構成する各単電池の端子を選択して差動増幅器４に出力させることができ、差動増幅器４から入力されたアナログ電圧をＡＤコンバータでデジタル電圧に変換することで、各単電池の電池電圧を測定することができる。 The multiplexers 2 and 3 are each connected to an output port of the microcomputer 5 through a cell switching output line. The microcomputer 5 includes an AD converter (not shown), and an output terminal of the differential amplifier 4 is connected to an AD input terminal of the microcomputer 5 (an input terminal of the AD converter). For this reason, the microcomputer 5 can select a terminal of each unit cell constituting the assembled battery 1 and output it to the differential amplifier 4 by sending a signal to the multiplexers 2 and 3 through the output port. By converting the analog voltage input from the dynamic amplifier 4 into a digital voltage by an AD converter, the battery voltage of each single cell can be measured.

本実施形態では、各単電池の電池電圧は、単電池の＋端子を入力とするマルチプレクサ２と単電池の−端子を入力とするマルチプレクサ３により切り替えられ、マルチプレクサ２とマルチプレクサ３との切替入力信号はマイコン５により別々に出力制御される。 In this embodiment, the battery voltage of each cell is switched by a multiplexer 2 that receives the + terminal of the cell and an multiplexer 3 that receives the-terminal of the cell, and a switching input signal between the multiplexer 2 and the multiplexer 3. Are controlled separately by the microcomputer 5.

また、マイコン５は、電気自動車全体を制御する車両側マイコン（上位の制御システム）と通信を行うための通信用ＩＣおよびインターフェースを有している。車両側マイコンと通信を行うための通信線は電池モジュールを構成する複数の電圧測定装置１０間でデージーチェーン状に接続されており、その一端が車両側マイコンのインターフェースに接続されている。 The microcomputer 5 includes a communication IC and an interface for communicating with a vehicle-side microcomputer (upper control system) that controls the entire electric vehicle. A communication line for communicating with the vehicle-side microcomputer is connected in a daisy chain between the plurality of voltage measuring devices 10 constituting the battery module, and one end thereof is connected to the interface of the vehicle-side microcomputer.

（動作）
次に、本実施形態の電圧測定装置１０の動作について、マイコン５のＣＰＵ（以下、単にＣＰＵという。）を主体として説明する。 (Operation)
Next, the operation of the voltage measuring apparatus 10 of the present embodiment will be described with a CPU of the microcomputer 5 (hereinafter simply referred to as “CPU”) as a subject.

ＣＰＵは、下表１に示す順番で、マルチプレクサ２、３の入力切替を行い、ＡＤコンバータを介して各単電池（セル）の電池電圧をデジタル値で取得する。 The CPU switches the inputs of the multiplexers 2 and 3 in the order shown in Table 1 below, and acquires the battery voltage of each single battery (cell) as a digital value via the AD converter.

表１において、セル１〜４は、組電池１を構成する各単電池を図１に示す上側から順にセル１〜４としたものであり（セル１は最上位の単電池、セル４は最下位の単電池）、Ｖ１〜Ｖ４はマイコン５のＡＤコンバータから出力される電圧であり、Ｖ１は各単電池の＋端子と−端子との両方を切り替える前のＡＤコンバータ測定値、Ｖ２は＋端子のみを切り替えた場合のＡＤコンバータ測定値、Ｖ３は−端子のみを切り替えた場合のＡＤコンバータ測定値、Ｖ４は＋端子と−端子との両方を切り替えた場合のＡＤコンバータ測定値である。なお、Ｖ１〜Ｖ４は単電池電圧を有しているものとする（Ｖ１＞０、Ｖ２＞０、Ｖ３＞０、Ｖ４＞０）。また、測定ＮＯは、マイコン５が１→８の順にマルチプレクサの切替と電圧測定を行うことを意味しており、本実施形態の電圧測定装置１０では、測定ＮＯ８が終了すると測定ＮＯ１に戻って動作を継続する。 In Table 1, cells 1 to 4 are cells 1 to 4 in order from the upper side shown in FIG. 1 (cell 1 is the highest cell, and cell 4 is the highest cell). V1 to V4 are voltages output from the AD converter of the microcomputer 5, V1 is the measured value of the AD converter before switching between the + terminal and the − terminal of each cell, and V2 is the + terminal. AD converter measured value when only switching is performed, V3 is an AD converter measured value when switching only the-terminal, and V4 is an AD converter measured value when both the + terminal and the-terminal are switched. In addition, V1-V4 shall have a cell voltage (V1> 0, V2> 0, V3> 0, V4> 0). The measurement NO means that the microcomputer 5 switches the multiplexer and measures the voltage in the order of 1 → 8. In the voltage measurement device 10 of the present embodiment, when the measurement NO8 ends, the measurement NO1 returns to the operation. Continue.

ＣＰＵは、マルチプレクサ２、マルチプレクサ３を同時には切り替えないで、いずれか片方を切り替えて次のステップ（測定ＮＯ）に移行する。 The CPU does not switch the multiplexer 2 and the multiplexer 3 at the same time, but switches one of them and moves to the next step (measurement NO).

ここで、表１に示すように、測定ＮＯ１、３、５、７は、各単電池の電池電圧が差動増幅器４からの出力電圧（各単電池の電圧）である。ＣＰＵは、従来技術と同様に、各単電池の電圧と、予めマイコン５のＲＯＭに格納されており、ＲＡＭに展開された過充電あるいは過放電電圧とを比較し、各単電池が過充電状態あるいは過放電状態にあるか否かを判断する。否定判断のときは、上述したように、次の測定ＮＯでの測定を行い、否定判断のときは通信線を介して車両側マイコンに特定の（過充電状態あるいは過放電状態にある）単電池の電池異常を報知する。車両側マイコンは、報知を受けると、電池異常がある旨をインストルメントパネルに表示する。これにより、ドライバはサービスステーションで特定の単電池、組電池１の修理点検、交換を受けることができる。 Here, as shown in Table 1, in measurement Nos. 1, 3, 5, and 7, the battery voltage of each single cell is the output voltage from the differential amplifier 4 (the voltage of each single cell). As with the prior art, the CPU compares the voltage of each single battery with the overcharge or overdischarge voltage preliminarily stored in the ROM of the microcomputer 5, and each single battery is overcharged. Or it is judged whether it is in an overdischarge state. When a negative determination is made, measurement is performed with the next measurement NO as described above. When a negative determination is made, a specific cell (in an overcharge state or an overdischarge state) is specified to the vehicle-side microcomputer via the communication line. Notify the battery abnormality. When receiving the notification, the vehicle-side microcomputer displays on the instrument panel that there is a battery abnormality. As a result, the driver can receive a repair check and replacement of a specific unit cell or the assembled battery 1 at the service station.

一方、測定ＮＯ２、４、６は単電池以外の２個の単電池の電圧の和が差動増幅器４の出力電圧となる。ＣＰＵは、測定ＮＯ１、３、５、７での測定値との比較を行い差があるか否かを判断する。差がない場合は、マルチプレクサに異常があるか、単電池電圧が０Ｖになったとみなすことができる。なお、測定ＮＯ８では差動増幅器４の出力電圧が負となるが、一般的なマイコン内蔵のＡＤコンバータは負電圧が測定できず０Ｖと検出される。このため、ＣＰＵは、０Ｖ以外の場合に、マルチプレクサの異常か、電池電圧が負の異常電圧となったと判定することができる。従って、ＣＰＵは、Ｖ１とＶ４とが０Ｖではなく、かつ、Ｖ１ないしＶ４の値が同一（または予め定められた所定範囲内）の場合に、電圧測定装置１０が故障したと判断することができる。装置故障の判断をすると、ＣＰＵは、通信線を介して車両側マイコンに電圧測定装置１０の装置故障を報知する。車両側マイコンは、報知を受けると、電圧測定装置１０の装置故障をインストルメントパネルに表示する。これにより、ドライバはサービスステーションで電圧測定装置１０の修理点検、交換を受けることができる。 On the other hand, in the measurement NOs 2, 4, and 6, the sum of the voltages of two unit cells other than the unit cell becomes the output voltage of the differential amplifier 4. The CPU compares the measured values in measurement NOs 1, 3, 5, and 7 to determine whether there is a difference. When there is no difference, it can be considered that there is an abnormality in the multiplexer or the unit cell voltage has become 0V. In measurement NO8, the output voltage of the differential amplifier 4 is negative. However, a general AD converter with a built-in microcomputer cannot measure the negative voltage and is detected as 0V. For this reason, the CPU can determine that the multiplexer is abnormal or the battery voltage has become a negative abnormal voltage when the voltage is other than 0V. Therefore, the CPU can determine that the voltage measuring device 10 has failed when V1 and V4 are not 0 V and the values of V1 to V4 are the same (or within a predetermined range). . When the device failure is determined, the CPU notifies the vehicle-side microcomputer of the device failure of the voltage measuring device 10 via the communication line. When receiving the notification, the vehicle-side microcomputer displays a device failure of the voltage measuring device 10 on the instrument panel. As a result, the driver can receive a repair check and replacement of the voltage measuring device 10 at the service station.

（作用・効果等）
本実施形態の電圧測定装置１０は、測定対象となる単電池を順番に切り替える場合に、マルチプレクサ２、３を同時に切り替えないで、＋端子のみ切り替えた状態と−端子のみ切り替えた状態とでも差動増幅器４の出力電圧を検出（ＡＤコンバータを介して測定）するので、マルチプレクサが正常に切り替わっていること及び故障したことを検出することができる。従来技術では、電圧検出系統を二系統有し、いずれかの系統が故障した場合でも異常な状態を検出して電池の充放電を止めることができたが、本発明では電圧測定回路１０が故障したことを検出することができるので、電圧検出系統が一系統のみで電池の充放電を止めることができる。このため、本実施形態の電圧測定装置１０は、構成回路をコンパクトにすることができ、コストを低減させることができる。 (Action / Effect)
In the voltage measuring apparatus 10 of this embodiment, when the cells to be measured are sequentially switched, the multiplexers 2 and 3 are not switched at the same time, and only the + terminal is switched and the − terminal is switched. Since the output voltage of the amplifier 4 is detected (measured through an AD converter), it is possible to detect that the multiplexer has switched normally and has failed. In the prior art, there are two voltage detection systems, and even when one of the systems fails, an abnormal state can be detected and charging / discharging of the battery can be stopped. However, in the present invention, the voltage measurement circuit 10 fails. Therefore, the charging / discharging of the battery can be stopped with only one voltage detection system. For this reason, the voltage measuring apparatus 10 of this embodiment can make a structural circuit compact, and can reduce cost.

図３に、各単電池の電圧が図中に表記されている場合の差動増幅器の入力電圧と出力電圧との変化を示す。図３に示すように、単電池電圧以外の測定時には出力電圧が変化しており、変化しない場合は単電池電圧が０Ｖの異常状態か、マルチプレクサが故障したと判断できることが分かる。 FIG. 3 shows changes in the input voltage and output voltage of the differential amplifier when the voltage of each unit cell is shown in the figure. As shown in FIG. 3, it can be seen that the output voltage changes at the time of measurement other than the unit cell voltage, and if it does not change, it can be determined that the unit cell voltage is in an abnormal state of 0 V or that the multiplexer has failed.

なお、本実施形態では、組電池１を４直列のリチウムイオン二次電池で構成した例を示したが、本発明はこれに限定されるものでない。すなわち、組電池である必要はなく、直並列に接続された電池群一般に適用でき、直列数も４直列に限られるものではない。また、本実施形態では、説明を簡単にするため、マルチプレクサ２、３及び差動増幅器４を別々に示したが、これらを一体とした回路ないしユニットを構成するようにしてもよい。更に、マイコン５にＡＤコンバータを内蔵した例を示したが、ＡＤコンバータをマイコン５の外に配置するようにしてもよいことは云うまでもない。また、本実施形態では、上位の制御システムとして車両側マイコンを例示したが、電池モジュール全体を制御するマイコンを上位の制御システムとしてそのマイコンに電池異常ないし装置異常を報知するようにしてもよい。 In the present embodiment, an example in which the assembled battery 1 is configured by four series lithium ion secondary batteries has been described, but the present invention is not limited to this. That is, it is not necessary to be an assembled battery, and it can be applied to general battery groups connected in series and parallel, and the number of series is not limited to 4 series. In the present embodiment, the multiplexers 2 and 3 and the differential amplifier 4 are shown separately for the sake of simplicity, but a circuit or unit in which these are integrated may be configured. Furthermore, although the example in which the AD converter is built in the microcomputer 5 is shown, it goes without saying that the AD converter may be arranged outside the microcomputer 5. In the present embodiment, the vehicle-side microcomputer is exemplified as the host control system. However, the microcomputer that controls the entire battery module may be used as a host control system to notify the microcomputer of battery abnormality or device abnormality.

本発明は単電池の電圧検出系を二系統用いずに、単電池電圧の検出が正常に切り替わっていることを検出できる電圧測定装置を提供するものであるため、回路をコンパクト化、低コスト化できることから、電圧測定装置の製造、販売に寄与するので、産業上の利用可能性を有する。 The present invention provides a voltage measuring device that can detect that the detection of the cell voltage has been switched normally without using two cell voltage detection systems, so that the circuit can be made compact and low in cost. Since it contributes to the manufacture and sale of voltage measuring devices, it has industrial applicability.

本発明が適用可能な実施形態の電圧測定装置のブロック回路図である。1 is a block circuit diagram of a voltage measuring device according to an embodiment to which the present invention is applicable. 従来の電圧測定装置のブロック回路図である。It is a block circuit diagram of the conventional voltage measuring device. 実施形態の電圧測定装置で単電池電圧を測定した場合の差動増幅器の入出力電圧の変化を示す特性線図である。It is a characteristic diagram which shows the change of the input-output voltage of a differential amplifier at the time of measuring a cell voltage with the voltage measuring device of embodiment.

Explanation of symbols

１組電池（電池群）
２マルチプレクサ（第１のマルチプレクサ）
３マルチプレクサ（第２のマルチプレクサ）
４差動増幅器
５マイコン
１０電圧測定装置 1 battery pack (battery group)
2 Multiplexer (first multiplexer)
3 Multiplexer (second multiplexer)
4 differential amplifier 5 microcomputer 10 voltage measuring device

Claims

A first multiplexer that selects the + terminal of each unit cell of the battery group in which the unit cells are connected in series, and a second multiplexer that selects the-terminal of each unit cell; In the voltage measuring device for measuring the voltage of each unit cell by connecting the − terminal to the + input terminal and the − input terminal of the differential amplifier, respectively, and detecting the output voltage of the differential amplifier via an AD converter . ,
A voltage is measured by selecting the + terminal of the lowest cell constituting the battery group by the first multiplexer and the-terminal of the lowest cell by the second multiplexer, and measuring the voltage. The voltage is measured by selecting the + terminal of the cell higher than the lowest cell and the-terminal of the lowest cell by the second multiplexer, and measuring the voltage by the first multiplexer. By measuring the voltage by selecting the + terminal of the upper cell, and the-terminal of the upper cell by the second multiplexer, the first and second multiplexers are respectively connected to the lower cell. Measure the voltage by switching from the battery to the upper cell one by one from the top to the bottom
The first multiplexer selects the + terminal of the uppermost cell, the second multiplexer selects the minus terminal of the cell that is one level lower than the uppermost cell, and measures the voltage. The multiplexer selects the + terminal of the uppermost cell, the second multiplexer selects the − terminal of the uppermost cell, and measures the voltage, and the first multiplexer measures the lower cell. By measuring the voltage by selecting the-terminal and the-terminal of the top cell by the second multiplexer,
When the unit cells to be measured can exchange cut sequentially, the state in which the switching only the first and second of said positive terminal not switch simultaneously multiplexer - also to measure the voltage in a state of switching the terminal only , Compare the measured voltage to diagnose the device,
A voltage measuring device characterized by that.

A first multiplexer that selects the + terminal of each unit cell of the battery group in which the unit cells are connected in series, and a second multiplexer that selects the-terminal of each unit cell; In the voltage measuring device for measuring the voltage of each unit cell by connecting the − terminal to the + input terminal and the − input terminal of the differential amplifier, respectively, and detecting the output voltage of the differential amplifier via an AD converter. ,
A voltage is measured by selecting the + terminal of the lowest cell constituting the battery group by the first multiplexer and the-terminal of the lowest cell by the second multiplexer, and measuring the voltage. To select the + terminal of the lowest cell, and the second multiplexer to select the-terminal of the cell that is one higher than the lowest cell, and measure the voltage, and the first multiplexer to measure the voltage. By measuring the voltage by selecting the + terminal of the upper cell, and the-terminal of the upper cell by the second multiplexer, the first and second multiplexers are respectively connected to the lower cell. Measure the voltage by switching from the battery to the upper cell one by one from the top to the bottom
The first multiplexer selects the + terminal of the cell that is one level lower than the highest level, the second multiplexer selects the-terminal of the highest level cell, and measures the voltage. A voltage is measured by selecting a positive terminal of the uppermost cell, a negative terminal of the uppermost cell by the second multiplexer, and a positive terminal of the uppermost cell by the first multiplexer. By selecting the negative terminal of the lowest cell in the second multiplexer and measuring the voltage,
When switching the cells to be measured in order, the voltage is measured in the state where only the + terminal is switched without switching the first and second multiplexers at the same time, and the state where only the − terminal is switched, Compare the measured voltage to diagnose the device,
A voltage measuring device characterized by that.

The value of the measurement voltage before switching both the + terminal and the − terminal and the value of the measurement voltage when switching both the + terminal and the − terminal are not 0 V, and the + terminal A device failure is diagnosed when the measured voltage before switching both of the − terminal and the value of the measured voltage when switching both of the + terminal and the − terminal are the same or within a predetermined setting range. The voltage measuring device according to claim 1 or 2, wherein

The voltage measuring device according to claim 3, wherein a signal is sent to a higher-level control system when the device failure is diagnosed.