JP2003282158A - Battery voltage measuring circuit - Google Patents
Battery voltage measuring circuitInfo
- Publication number
- JP2003282158A JP2003282158A JP2002084814A JP2002084814A JP2003282158A JP 2003282158 A JP2003282158 A JP 2003282158A JP 2002084814 A JP2002084814 A JP 2002084814A JP 2002084814 A JP2002084814 A JP 2002084814A JP 2003282158 A JP2003282158 A JP 2003282158A
- Authority
- JP
- Japan
- Prior art keywords
- battery
- amplifier
- voltage
- battery voltage
- output
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- 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
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は電池電圧測定回路に
係り、特に、組電池を構成する各二次電池の電池電圧を
測定する電池電圧測定回路に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery voltage measuring circuit, and more particularly to a battery voltage measuring circuit for measuring the battery voltage of each secondary battery constituting an assembled battery.
【０００２】[0002]
【従来の技術】従来、組電池の状態監視方法として、組
電池を構成する各単電池（単セル）の電圧が測定されて
いる。特に、近年用いられるようになったリチウムイオ
ン電池では、過充電及び過放電の保護のためと、単電池
間の残存容量バラツキを少なくする容量調整のため、精
度良く各単電池の電圧を検出しなければならない。その
検出方法としては、差動増幅器を用いて各単電池の電圧
を組電池のマイナス端子基準に変換し、ＡＤコンバータ
で単電池電圧を測定する方法が一般的である。2. Description of the Related Art Conventionally, as a method of monitoring the state of an assembled battery, the voltage of each unit cell (single cell) constituting the assembled battery has been measured. In particular, with lithium-ion batteries that have come to be used in recent years, the voltage of each single battery can be accurately detected in order to protect against overcharging and overdischarging and to adjust the capacity to reduce variations in the remaining capacity between single batteries. There must be. As a detection method, a method of converting the voltage of each unit cell into a negative terminal reference of the assembled battery using a differential amplifier and measuring the unit cell voltage with an AD converter is generally used.
【０００３】また、電気自動車用の電源などでは８〜１
０直列程度の組電池が提案され実用化されようとしてい
る。その場合の電池電圧測定回路の構成も差動増幅器を
用いたものが使用されている。図３に８直列での電池電
圧測定回路の構成例を示す。この電池電圧測定回路で
は、８直列に接続されたリチウムイオン電池（単電池）
１の各端子電圧が各々分圧部２で分圧され、マルチプレ
クサ３に入力される。分圧部２の出力側に挿入されてい
るコンデンサは、ＲＣフイルタの役目を果たすものであ
る。マルチプレクサ３の出力は差動増幅部４に入力さ
れ、差動増幅器４で分圧比分が増幅されて各単電池の出
力電圧となる。この出力電圧は単電池電圧そのものであ
り、マイクロコンピュータ５（以下、マイコン５とい
う。）に内蔵されたＡＤコンバータに入力され、マイコ
ン５で単電池電圧のデジタル値が取得（測定）される。
マルチプレクサ３は電池電圧を検出する単電池を選択す
るもので、マイコン５で測定する単電池の選択が行われ
る。なお、マイコン５の作動電源は電源部６を介して８
直列の組電池から供給される。In addition, the power source for electric vehicles is 8 to 1
An assembled battery of about 0 series has been proposed and is about to be put to practical use. In that case, the battery voltage measuring circuit also uses a differential amplifier. FIG. 3 shows a configuration example of a battery voltage measuring circuit in 8 series. In this battery voltage measuring circuit, 8 series connected lithium ion batteries (single battery)
Each terminal voltage of 1 is divided by the voltage dividing unit 2 and input to the multiplexer 3. The capacitor inserted on the output side of the voltage dividing unit 2 serves as an RC filter. The output of the multiplexer 3 is input to the differential amplifier 4, and the voltage division ratio is amplified by the differential amplifier 4 to become the output voltage of each unit cell. This output voltage is the unit cell voltage itself and is input to the AD converter built in the microcomputer 5 (hereinafter referred to as the microcomputer 5), and the microcomputer 5 acquires (measures) a digital value of the unit cell voltage.
The multiplexer 3 selects a single battery for detecting the battery voltage, and the single battery to be measured by the microcomputer 5 is selected. The operating power source of the microcomputer 5 is 8 via the power source unit 6.
It is supplied from a series assembled battery.
【０００４】[0004]
【発明が解決しようとする課題】ところが、上記電池電
圧測定回路では、電圧検出精度を確保するために高精度
の抵抗が必要なため、コスト高となる、という課題を有
している。また、要求精度によっては実現不可能な場合
もある。However, the battery voltage measuring circuit described above has a problem that the cost becomes high because a highly accurate resistor is required to secure the voltage detection accuracy. Further, it may not be possible depending on the required accuracy.
【０００５】すなわち、図３に示す電池電圧測定回路で
は、８直列の組電池で差動増幅部４の２個のＯＰアンプ
で差動増幅を行い、ＡＤコンバータ内蔵のマイコン５で
単電池の電圧を取得するが、電圧検出誤差に影響する因
子は、分圧部２の抵抗精度、差動増幅部４の抵抗精度、
差動増幅部４のＯＰアンプのオフセット電圧、ＡＤコン
バータ自体の誤差、ＡＤコンバータの基準電圧源の基準
電圧Ｖｒｅｆの精度である。実現可能な値として、抵抗
の精度を０．１％、ＯＰアンプのオフセット電圧を５ｍ
Ｖ、基準電圧源の精度を０．１％、ＡＤコンバータ自体
の精度を±３ＬＳＢ、単電池の電池電圧を４．３５Ｖと
し、図４に示す等価回路を想定して、８直列の最上位単
電池の電圧検出誤差の２乗平均値を計算すると下表１の
通りとなる。That is, in the battery voltage measuring circuit shown in FIG. 3, two OP amplifiers of the differential amplifying section 4 perform differential amplification with an assembled battery in 8 series, and the microcomputer 5 with a built-in AD converter performs voltage amplification of a single battery. However, the factors that affect the voltage detection error are the resistance accuracy of the voltage dividing unit 2, the resistance accuracy of the differential amplifier unit 4,
These are the offset voltage of the OP amplifier of the differential amplifier 4, the error of the AD converter itself, and the accuracy of the reference voltage Vref of the reference voltage source of the AD converter. As the achievable values, the resistance accuracy is 0.1% and the OP amplifier offset voltage is 5 m.
V, the accuracy of the reference voltage source is 0.1%, the accuracy of the AD converter itself is ± 3 LSB, and the battery voltage of the single battery is 4.35 V. Assuming the equivalent circuit shown in FIG. Table 1 below shows the root mean square value of the battery voltage detection errors.
【０００６】[0006]
【表１】 [Table 1]
【０００７】なお、表１において、Ｖｏｆｆ１、Ｖｏｆ
ｆ２はＯＰアンプ１１、２２のオフセット電圧、ＡＤ誤
差はＡＤコンバータの誤差、Ｖｐ、Ｖｍは組電池のマイ
ナス端子基準とした最上位単電池の＋端子、−端子の電
圧、ＶＴ、ＶＯは下式（１）、（２）で表されるＯＰア
ンプ１１、２２の出力電圧、検出値は下式（３）で表さ
れるＡＤコンバータの出力電圧である。また、表１にお
いて、誤差、誤差２乗値、誤差の２乗平均値は、それぞ
れ、誤差（ｍＶ）＝｛検出値（ｍＶ）−電池電圧の基準
値（４３５０ｍＶ）｝、誤差２乗値＝（誤差）２、誤差
の２乗平均値＝（誤差２乗値の合計）１／２で与えられ
る（後述する表２においても同じ。）。In Table 1, Voff1, Vof
f2 is the offset voltage of the OP amplifiers 11 and 22, AD error is the error of the AD converter, Vp and Vm are the positive and negative terminal voltages of the highest-ranking unit cell based on the negative terminal of the assembled battery, and VT and VO are the following equations. The output voltages and the detected values of the OP amplifiers 11 and 22 represented by (1) and (2) are the output voltages of the AD converter represented by the following equation (3). Further, in Table 1, the error, the error square value, and the mean square value of the error are respectively error (mV) = {detection value (mV) −reference value of battery voltage (4350 mV)}, error square value = (Error) 2 , the mean square value of the error = (sum of the error square values) 1/2 (the same applies to Table 2 described later).
【０００８】[0008]
【数１】 [Equation 1]
【０００９】表１に示すように、０．１％精度の高精度
かつ高コストの抵抗を用いても、誤差の２乗平均値は６
７．６ｍＶであり、リチウムイオン電池で必要な電圧検
出精度の±５０ｍＶを満足するのは困難なため、実用化
するには完成後の回路を検査して電圧検出誤差を測定し
選別して使用していた。その場合、当然歩留まりは悪く
なりコストはあがってしまう。As shown in Table 1, even if a highly accurate and costly resistor with 0.1% accuracy is used, the mean square value of the error is 6
Since it is 7.6 mV and it is difficult to meet the voltage detection accuracy of ± 50 mV required for lithium-ion batteries, the circuit after completion is inspected and voltage detection errors are measured and selected for practical use. Was. In that case, of course, the yield is lowered and the cost is increased.
【００１０】また、この電池電圧測定回路では、単電池
と分圧部２とが直結されているので、電池電圧測定回路
未使用時に単電池から流れ込む電流、つまり暗電流が流
れてしまう。この暗電流は電池の放置特性に影響を及ぼ
すので、できるだけ小さい値にしなければならず、その
ためには分圧部の抵抗を高抵抗値にする必要がある。し
かしながら、精度の良い高抵抗は実現が困難で、実現で
きたとしても信頼性が低い、という問題がある。更に、
高抵抗値とするとインピーダンスが高くなり、ノイズの
影響を受けやすいのでフイルタ特性を向上させなければ
ならない。分圧部２中に挿入されているコンデンサは対
ノイズ性のために必要不可欠なものである。Further, in this battery voltage measuring circuit, since the unit cell and the voltage dividing unit 2 are directly connected, a current flowing from the unit cell when the battery voltage measuring circuit is not used, that is, a dark current flows. Since this dark current affects the leaving characteristics of the battery, it has to be as small as possible, and for that purpose, the resistance of the voltage dividing portion needs to have a high resistance value. However, there is a problem that it is difficult to realize a highly accurate high resistance, and even if it is realized, the reliability is low. Furthermore,
If the resistance value is high, the impedance becomes high and it is easily affected by noise, so the filter characteristics must be improved. The capacitor inserted in the voltage dividing unit 2 is indispensable for noise resistance.
【００１１】この解決方法として、直列単電池数と同一
数の絶縁アンプを用いてグランドを絶縁することも考え
られるが、絶縁アンプは特殊で高価であることからコス
トの点で不可能である。As a solution to this problem, it is conceivable to use the same number of insulation amplifiers as the number of series cells to insulate the ground, but the insulation amplifiers are special and expensive, which is impossible in terms of cost.
【００１２】本発明は上記事案に鑑み、絶縁アンプ等の
増幅器や高精度の抵抗を使わずに必要な電圧検出精度を
確保し、ノイズの影響を受けにくい電池電圧測定回路を
提供することを課題とする。In view of the above problems, the present invention aims to provide a battery voltage measuring circuit which secures necessary voltage detection accuracy without using an amplifier such as an insulation amplifier or a highly accurate resistor and is less susceptible to noise. And
【００１３】[0013]
【課題を解決するための手段】上記課題を解決するため
に、本発明は、組電池を構成する各二次電池の電池電圧
を測定する電池電圧測定回路において、ＡＤコンバータ
を内蔵し前記組電池から絶縁された電源で作動するマイ
クロコンピュータと、前記二次電池に接続されたフォト
ＭＯＳリレーとを備え、前記マイクロコンピュータは前
記ＡＤコンバータの入力端子に測定対象の二次電池の端
子を接続するように前記フォトＭＯＳリレーを制御して
前記ＡＤコンバータの出力から該二次電池の電池電圧を
取得する。In order to solve the above-mentioned problems, the present invention provides a battery voltage measuring circuit for measuring the battery voltage of each secondary battery which constitutes an assembled battery, wherein the assembled battery has a built-in AD converter. And a photoMOS relay connected to the secondary battery, the microcomputer connecting the input terminal of the AD converter to the terminal of the secondary battery to be measured. Then, the photo MOS relay is controlled to obtain the battery voltage of the secondary battery from the output of the AD converter.
【００１４】本発明の電池電圧測定回路は、ＡＤコンバ
ータを内蔵し組電池から絶縁された電源で作動するマイ
クロコンピュータ（以下、マイコンという。）と、組電
池を構成する二次電池に接続されたフォトＭＯＳリレー
とを備えており、マイコンの電源は組電池から絶縁され
ている。マイコンは、測定対象の二次電池の電池電圧を
測定するときのみフォトＭＯＳリレーを制御して（オン
状態として）、ＡＤコンバータの入力端子に該二次電池
の＋端子を接続させると共に、ＡＤコンバータのグラン
ドに該二次電池の−端子を接続させ、ＡＤコンバータの
出力から測定対象の二次電池の電池電圧を取得する。The battery voltage measuring circuit of the present invention is connected to a microcomputer (hereinafter referred to as a microcomputer) which has a built-in AD converter and operates by a power source insulated from the assembled battery, and a secondary battery constituting the assembled battery. A photo MOS relay is provided, and the power supply of the microcomputer is insulated from the assembled battery. The microcomputer controls the photo-MOS relay only when measuring the battery voltage of the secondary battery to be measured (turned on), connects the + terminal of the secondary battery to the input terminal of the AD converter, and The negative terminal of the secondary battery is connected to the ground of, and the battery voltage of the secondary battery to be measured is acquired from the output of the AD converter.
【００１５】本発明によれば、マイコンの電源が組電池
から絶縁され、測定対象の二次電池の電池電圧を測定す
るときにフォトＭＯＳリレーを制御して該二次電池の電
池電圧を取得するようにしたので、従来の回路のように
分圧回路と差動増幅回路などを用いて組電池のグランド
端子基準に電池電圧を変換したり絶縁アンプ等の特殊な
増幅器を用いる必要はなく、かつ、高精度の抵抗を使わ
ずに必要な電圧検出精度を確保して二次電池の電池電圧
を測定することができる。According to the present invention, the power supply of the microcomputer is insulated from the assembled battery, and when measuring the battery voltage of the secondary battery to be measured, the photoMOS relay is controlled to acquire the battery voltage of the secondary battery. Therefore, unlike the conventional circuit, it is not necessary to use a voltage divider circuit and a differential amplifier circuit to convert the battery voltage to the ground terminal reference of the assembled battery or to use a special amplifier such as an isolation amplifier, and It is possible to measure the battery voltage of the secondary battery while ensuring the necessary voltage detection accuracy without using a highly accurate resistor.
【００１６】この場合において、入力端子に二次電池の
接続点の電圧が入力され、出力端子がフォトＭＯＳリレ
ーに接続されたバッファを更に備え、該バッファの作動
電源を一つ上位のバッファの出力と一つ下位のバッファ
の出力とから供給するようにすれば、ＡＤコンバータに
はバッファを介して二次電池の電池電圧が入力されるの
で、バッファの入力に時定数の大きなＲＣフイルタを挿
入することにより、ノイズに対する感度を低くし安定し
て二次電池の電池電圧を測定することができると共に、
バッファの出力インピーダンスは低いため、フォトＭＯ
Ｓリレーにオン抵抗の大きい廉価品を用いても電圧検出
誤差が増加することはない。In this case, the input terminal is supplied with the voltage at the connection point of the secondary battery and the output terminal is further provided with a buffer connected to the photoMOS relay. If it is supplied from the output of one lower buffer, the battery voltage of the secondary battery is input to the AD converter via the buffer, so an RC filter having a large time constant is inserted into the input of the buffer. This makes it possible to measure the battery voltage of the secondary battery stably with low sensitivity to noise,
Since the output impedance of the buffer is low, the photo MO
Even if a low-priced product having a large ON resistance is used for the S relay, the voltage detection error does not increase.
【００１７】[0017]
【発明の実施の形態】以下、８直列の電気自動車用電池
の組電池に、本発明に係る電池電圧測定回路を適用した
実施の形態について説明する。BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment in which the battery voltage measuring circuit according to the present invention is applied to an assembled battery of eight series electric vehicle batteries will be described.
【００１８】図１に示すように、組電池は８個のリチウ
ムイオン電池（以下、単電池という。）１が直列に接続
されて構成されている。本実施形態の電池電圧測定回路
は、組電池を構成する各単電池の電池電圧を測定する、
ＡＤコンバータ（図示省略）を内蔵したマイコン５を備
えている。マイコン５の作動電源は組電池とは絶縁され
た絶縁型電源部１０から供給される。絶縁型電源部１０
の電源は入力と出力とが絶縁されているので、組電池か
らとってもよいし別の電源からとってもよい。As shown in FIG. 1, the assembled battery is constructed by connecting eight lithium ion batteries (hereinafter referred to as unit cells) 1 in series. The battery voltage measurement circuit of the present embodiment measures the battery voltage of each unit cell that constitutes the assembled battery,
The microcomputer 5 including an AD converter (not shown) is provided. The operating power of the microcomputer 5 is supplied from an insulated power supply unit 10 which is insulated from the battery pack. Isolated power supply unit 10
Since the power source is isolated from the input and the output, it may be obtained from the assembled battery or from another power source.
【００１９】また、電池電圧測定回路は、ノイズを排除
するためのＲＣフィルタ部７、入力側と出力側とのイン
ピーダンスを調整するためのバッファ部８、及び、スイ
ッチ機能を有し測定対象の二次電池の電圧をＡＤコンバ
ータに出力するフォトＭＯＳリレー部９を備えている。Further, the battery voltage measuring circuit has an RC filter section 7 for eliminating noise, a buffer section 8 for adjusting the impedance between the input side and the output side, and a switch function to be used as a measuring object. A photo MOS relay unit 9 that outputs the voltage of the secondary battery to the AD converter is provided.
【００２０】最上位を除く各単電池１の＋端子は抵抗Ｒ
の一端に接続されており、抵抗Ｒの他端は低消費電力型
のＯＰアンプの＋入力端子に接続されている。ＯＰアン
プの−入力端子は出力端子に接続されており、ＯＰアン
プの出力端子はフォトＭＯＳリレー部９に接続されてい
る。また、ＯＰアンプの＋電源端子は当該入力端子の一
つ上位側の単電池の＋出力電圧と同電位である、一つ上
位のＯＰアンプの出力端子に接続されており、−電源端
子は当該入力端子の一つ下位側の単電池の−出力電圧と
同電位である、一つ下位のＯＰアンプの出力端子に接続
されている。更に、最上位及び最下位単電池を除き、抵
抗Ｒの他端にはコンデンサの一端が接続されており、コ
ンデンサの他端は一つ下位の抵抗Ｒの他端に接続されて
いる。The positive terminal of each unit cell 1 excluding the highest rank has a resistance R
, And the other end of the resistor R is connected to the + input terminal of the low power consumption type OP amplifier. The-input terminal of the OP amplifier is connected to the output terminal, and the output terminal of the OP amplifier is connected to the photoMOS relay unit 9. Further, the + power supply terminal of the OP amplifier is connected to the output terminal of the OP amplifier of the one higher rank, which is the same potential as the + output voltage of the unit cell on the higher rank side of the input terminal, and the −power supply terminal is the same. It is connected to the output terminal of the OP amplifier of the one lower order, which has the same potential as the-output voltage of the unit cell of the lower order side of the input terminal. Further, one end of the capacitor is connected to the other end of the resistor R, and the other end of the capacitor is connected to the other end of the resistor R, which is one order lower, except for the highest and lowest cells.
【００２１】抵抗Ｒ及びＯＰアンプの数は単電池の数よ
り１だけ少ない数とされている。最上位単電池の＋端子
は、対応するコンデンサの一端、最上位ＯＰアンプの＋
電源端子及びフォトＭＯＳリレー部９に接続されてお
り、最下位単電池の−端子は、対応するコンデンサの他
端、最下位ＯＰアンプの−電源端子及びフォトＭＯＳリ
レー部９に接続されている。The number of resistors R and OP amplifiers is one less than the number of unit cells. The + terminal of the highest-order unit cell is at one end of the corresponding capacitor
The negative terminal of the lowest unit cell is connected to the power terminal and the photo MOS relay section 9, and the negative terminal of the corresponding capacitor is connected to the negative terminal of the lowest OP amplifier and the photo MOS relay section 9.
【００２２】従って、８直列の単電池１はＲＣフイルタ
部７を介してバッファ部８の入力となり、バッファ部８
に入力された単電池１の電池電圧はそのまま出力電圧と
してフォトＭＯＳリレー部９へ出力される。Therefore, the 8-series unit cells 1 are input to the buffer section 8 via the RC filter section 7, and the buffer section 8
The battery voltage of the unit cell 1 input to is output as it is to the photo MOS relay unit 9 as an output voltage.
【００２３】フォトＭＯＳリレー部９は、ＭＯＳ型スイ
ッチング素子のアレーで構成されている。スイッチング
素子の数は単電池数の２倍とされており、２つのスイッ
チング素子を１組としてマイコン５の出力ポートからの
指定（ハイレベル信号の送出）により同時にオン、オフ
制御される。１組とされた２つのスイッチング素子のう
ち上位側のスイッチング素子の入力側には対応する単電
池１の＋端子の電圧が入力され、下位側のスイッチング
素子の入力側には該単電池１の−端子の電圧が入力され
る。The photo MOS relay section 9 is composed of an array of MOS type switching elements. The number of switching elements is twice the number of single cells, and two switching elements are set as one set and are simultaneously turned on and off by designation (sending a high level signal) from the output port of the microcomputer 5. The voltage of the + terminal of the corresponding single cell 1 is input to the input side of the upper switching element of the two switching elements that make up one set, and the input terminal of the lower switching element of the single cell 1 is input. -The terminal voltage is input.
【００２４】すなわち、フォトＭＯＳリレー部９の入力
側では、最上位の単電池の＋端子が最上位のスイッチン
グ素子に接続されており、最下位の単電池の−端子は最
下位のスイッチング素子に接続されている。ＯＰアンプ
の出力端子は、最上位及び最下位のスイッチング素子を
除くスイッチング素子の入力側及び当該スイッチング素
子より一つ下位のスイッチング素子の入力側に接続され
ている。That is, on the input side of the photoMOS relay section 9, the + terminal of the highest unit cell is connected to the highest switching element, and the − terminal of the lowest unit cell is the lowest switching element. It is connected. The output terminal of the OP amplifier is connected to the input side of the switching elements excluding the uppermost and lowermost switching elements and the input side of the switching element one lower than the switching element.
【００２５】各組の上位側のスイッチング素子の出力側
はＡＤコンバータの入力端子に接続されており、下位側
のスイッチング素子の出力側はＡＤコンバータのグラン
ド端子に接続されている。The output side of the upper side switching element of each set is connected to the input terminal of the AD converter, and the output side of the lower side switching element is connected to the ground terminal of the AD converter.
【００２６】次に、本実施形態の電池電圧測定回路の動
作について説明する。Next, the operation of the battery voltage measuring circuit of this embodiment will be described.
【００２７】マイコン５は、フォトＭＯＳリレー部９に
測定対象の単電池１に対応する１組の（２つの）スイッ
チング素子をオン状態とするために、出力ポートからフ
ォトＭＯＳリレー部９へハイレベル信号を出力する。こ
れにより、１組のスイッチング素子はオン状態となり、
ＡＤコンバータの入力端子、グランド端子には、それぞ
れ測定対象の単電池の＋端子、−端子の電圧が入力さ
れ、ＡＤコンバータの出力からは測定対象の電池電圧が
デジタル化されて出力される。マイコン５は、この電池
電圧を測定対象の単電池の電池電圧として取得し、測定
対象の単電池の電池電圧取得後にオン状態とした１組の
スイッチング素子をオフ状態として、次の測定対象の単
電池に対応する１組のスイッチング素子をオン状態とし
て、同様に当該単電池の電池電圧を取得する。The microcomputer 5 outputs a high level signal from the output port to the photo MOS relay unit 9 so that the photo MOS relay unit 9 turns on a set of (two) switching elements corresponding to the unit cell 1 to be measured. Output a signal. As a result, one set of switching elements is turned on,
The voltage of the + terminal and-terminal of the unit cell to be measured is input to the input terminal and the ground terminal of the AD converter, respectively, and the voltage of the battery to be measured is digitized and output from the output of the AD converter. The microcomputer 5 obtains this battery voltage as the battery voltage of the unit cell to be measured, turns off one set of switching elements that are in the ON state after obtaining the battery voltage of the unit cell to be measured, and sets the next unit cell to be measured. Similarly, the battery voltage of the unit cell is acquired by turning on a set of switching elements corresponding to the battery.
【００２８】次に、本実施形態の電池電圧測定回路の作
用等について説明する。Next, the operation and the like of the battery voltage measuring circuit of this embodiment will be described.
【００２９】本実施形態の電池電圧測定回路では、マイ
コン５の作動電源が組電池から絶縁されており、測定対
象の単電池１の電池電圧を測定するときのみフォトＭＯ
Ｓリレー５を制御して１組のスイッチング素子をオン状
態とし該単電池１の電池電圧を取得するようにした。こ
のため、従来の回路のように分圧回路と差動増幅回路を
用いて組電池のグランド端子基準に電池電圧を変換した
り絶縁アンプ等の特殊な増幅器や高精度の抵抗を使用し
ていないので、回路構成も簡単で消費電流が小さく、低
コストの電池電圧測定回路を実現することができる。In the battery voltage measuring circuit of this embodiment, the operating power supply of the microcomputer 5 is insulated from the assembled battery, and the photo MO is used only when the battery voltage of the unit cell 1 to be measured is measured.
The S relay 5 is controlled to turn on one set of switching elements, and the battery voltage of the unit cell 1 is acquired. Therefore, unlike the conventional circuit, it does not use a voltage divider circuit and a differential amplifier circuit to convert the battery voltage based on the ground terminal of the battery pack, and does not use a special amplifier such as an insulation amplifier or a high-precision resistor. Therefore, it is possible to realize a low-cost battery voltage measuring circuit with a simple circuit configuration and low current consumption.
【００３０】また、本実施形態の電池電圧測定回路にお
いて電圧検出精度に影響する因子は、バッファ部８のＯ
Ｐアンプのオフセット電圧、ＡＤコンバータ自体の誤
差、ＡＤコンバータの基準電源源の基準電圧Ｖｒｅｆの
精度だけであり、従来技術に示したように分圧部の抵抗
精度や差動増幅回路の抵抗精度が影響を与えることはな
い。このため、本実施形態の電池電圧測定回路は、単電
池１の必要な電圧検出精度を確保して二次電池の電池電
圧を測定することができる。Further, in the battery voltage measuring circuit of the present embodiment, the factor affecting the voltage detection accuracy is O of the buffer section 8.
It is only the offset voltage of the P amplifier, the error of the AD converter itself, and the accuracy of the reference voltage Vref of the reference power source of the AD converter. As shown in the prior art, the resistance accuracy of the voltage dividing section and the resistance accuracy of the differential amplifier circuit are It has no effect. Therefore, the battery voltage measuring circuit according to the present embodiment can measure the battery voltage of the secondary battery while ensuring the required voltage detection accuracy of the unit cell 1.
【００３１】本実施形態の電池電圧測定回路において、
ＯＰアンプのオフセット電圧を５ｍＶ、基準電圧源の精
度を０．１％、ＡＤコンバータ自体の精度を±３ＬＳＢ
とし、従来技術に示した電池電圧測定回路の部品と同一
の値を使用したときの、８直列の最上位から２番面の単
電池１の電圧検出誤差の２乗平均値を計算した結果を下
表２に示す。また、図２に従来の電圧測定回路に対応し
た等価回路を示す。なお、表２において、ＶＯは下式
（４）で表されるＯＰアンプ２２の出力電圧、検出値は
上述した式（３）で表されるＡＤコンバータの出力電圧
である。In the battery voltage measuring circuit of this embodiment,
The offset voltage of the OP amplifier is 5 mV, the accuracy of the reference voltage source is 0.1%, and the accuracy of the AD converter itself is ± 3 LSB.
Then, the result of calculating the root mean square value of the voltage detection error of the cell 1 on the second side from the top of the 8 series when the same values as the components of the battery voltage measuring circuit shown in the prior art are used It is shown in Table 2 below. FIG. 2 shows an equivalent circuit corresponding to the conventional voltage measuring circuit. In Table 2, VO is the output voltage of the OP amplifier 22 represented by the following equation (4), and the detected value is the output voltage of the AD converter represented by the above equation (3).
【００３２】[0032]
【表２】 [Table 2]
【００３３】[0033]
【数２】 [Equation 2]
【００３４】表２に示すように、本実施形態の電池電圧
測定回路の誤差の２乗平均値は２４．７ｍＶと、従来の
電池電圧測定回路の２乗平均値６７．６ｍＶに比べて、
誤差を約１／３にすることができた。As shown in Table 2, the mean square value of the error of the battery voltage measuring circuit of this embodiment is 24.7 mV, which is 67.6 mV of the mean square value of the conventional battery voltage measuring circuit.
The error could be reduced to about 1/3.
【００３５】更に、本実施形態の電池電圧測定回路で
は、バッファ部８には低消費電力型のＯＰアンプが用い
られ入力電圧はそのまま出力電圧とされており、ＯＰア
ンプの＋電源を一つ上位のＯＰアンプの出力端子からと
り、−電源を一つ下位のＯＰアンプの出力端子からとっ
ている。このため、単電池１間の入力端子に流れる電流
はＯＰアンプのバイアス電流のみであり、その値は極め
て小さい値のため、単電池１の消費電流は同一となり、
ＯＰアンプを接続して放置しても消費電流の差によって
電池電圧にバラツキが生ずることを防止することができ
る。また、バッファ部７の作動電源が直列接続された形
となるので、トータルの消費電力を最小限とすることが
できる。当然の事ながら、バッファ部８の入力インピー
ダンスは高いので、ＲＣフイルタ部７の抵抗Ｒの抵抗値
を高くしてフイルタ特性を高めノイズに強くでき、出力
インピーダンスも低く抑えることができる。更に、バッ
ファ部８の出力インピーダンスは低いので、フォトＭＯ
Ｓリレー９のオン抵抗が大きくても電池電圧測定回路の
誤差に与える影響は少ない。Further, in the battery voltage measuring circuit of this embodiment, a low power consumption type OP amplifier is used for the buffer section 8 and the input voltage is used as the output voltage as it is. , And the power source is taken from the output terminal of the OP amplifier one level below. Therefore, the current flowing in the input terminals between the unit cells 1 is only the bias current of the OP amplifier, and the value thereof is extremely small. Therefore, the current consumption of the unit cells 1 becomes the same,
Even if the OP amplifier is connected and left as it is, it is possible to prevent the battery voltage from varying due to the difference in current consumption. Moreover, since the operating power supplies of the buffer unit 7 are connected in series, the total power consumption can be minimized. As a matter of course, since the input impedance of the buffer unit 8 is high, the resistance value of the resistor R of the RC filter unit 7 can be increased to enhance the filter characteristics and to be resistant to noise, and the output impedance can be suppressed to be low. Furthermore, since the output impedance of the buffer unit 8 is low, the photo MO
Even if the ON resistance of the S relay 9 is large, the influence on the error of the battery voltage measuring circuit is small.
【００３６】[0036]
【発明の効果】以上説明したように、本発明によれば、
マイコンの電源が組電池から絶縁され、測定対象の二次
電池の電池電圧を測定するときにフォトＭＯＳリレーを
制御して該二次電池の電池電圧を取得するようにしたの
で、従来の回路のように分圧回路と差動増幅回路などを
用いて組電池のグランド端子基準に電池電圧を変換した
り絶縁アンプ等の特殊な増幅器を用いる必要はなく、か
つ、高精度の抵抗を使わずに必要な電圧検出精度を確保
して各二次電池の電池電圧を測定することができる、と
いう効果を得ることができる。As described above, according to the present invention,
The power supply of the microcomputer is insulated from the assembled battery, and when measuring the battery voltage of the secondary battery to be measured, the photoMOS relay is controlled to acquire the battery voltage of the secondary battery. It is not necessary to use a voltage divider circuit and a differential amplifier circuit to convert the battery voltage to the ground terminal reference of the assembled battery or to use a special amplifier such as an isolation amplifier, and without using a high-precision resistor. It is possible to obtain the effect that the battery voltage of each secondary battery can be measured while ensuring the required voltage detection accuracy.
【図１】本発明が適用可能な実施形態の電池電圧測定回
路の回路図である。FIG. 1 is a circuit diagram of a battery voltage measuring circuit of an embodiment to which the present invention is applicable.
【図２】実施形態の電池電圧測定回路の最上位から一つ
下位の単電池に対する誤差を算出するための従来技術の
電池電圧測定回路に対応した等価回路の回路図である。FIG. 2 is a circuit diagram of an equivalent circuit corresponding to a battery voltage measuring circuit of the related art for calculating an error with respect to a battery cell one level lower than the highest level of the battery voltage measuring circuit of the embodiment.
【図３】従来の電池電圧測定回路の回路図である。FIG. 3 is a circuit diagram of a conventional battery voltage measuring circuit.
【図４】従来の電池電圧測定回路の最上位単電池に対す
る誤差を算出するための等価回路の回路図である。FIG. 4 is a circuit diagram of an equivalent circuit for calculating an error of the conventional battery voltage measuring circuit with respect to the highest-order cell.
１ リチウムイオン電池（二次電池） ５ マイクロコンピュータ ７ ＲＣフィルタ部 ８ バッファ部 ９ フォトＭＯＳリレー部 １０ 絶縁型電源部 1 Lithium-ion battery (secondary battery) 5 Microcomputer 7 RC filter section 8 buffer section 9 Photo MOS relay section 10 Isolated power supply
───────────────────────────────────────────────────── フロントページの続き Ｆターム(参考） 2G016 CB01 CC01 CC12 CC16 CC27 CD10 CD14 5H030 AA04 AS06 FF43 FF44 ─────────────────────────────────────────────────── ─── Continued front page F-term (reference) 2G016 CB01 CC01 CC12 CC16 CC27 CD10 CD14 5H030 AA04 AS06 FF43 FF44
Claims (2)
を測定する電池電圧測定回路において、ＡＤコンバータ
を内蔵し前記組電池から絶縁された電源で作動するマイ
クロコンピュータと、前記二次電池に接続されたフォト
ＭＯＳリレーとを備え、前記マイクロコンピュータは前
記ＡＤコンバータの入力端子に測定対象の二次電池の端
子を接続するように前記フォトＭＯＳリレーを制御して
前記ＡＤコンバータの出力から該二次電池の電池電圧を
取得することを特徴とする電池電圧測定回路。1. A battery voltage measuring circuit for measuring a battery voltage of each secondary battery which constitutes an assembled battery, and a microcomputer which incorporates an AD converter and operates by a power source insulated from the assembled battery, and the secondary battery. And a photo MOS relay connected to the AD converter, the microcomputer controls the photo MOS relay so as to connect the terminal of the secondary battery to be measured to the input terminal of the AD converter, and controls the photo MOS relay from the output of the AD converter. A battery voltage measuring circuit characterized by acquiring a battery voltage of a secondary battery.
が入力され、出力端子が前記フォトＭＯＳリレーに接続
されたバッファを更に備え、該バッファの作動電源が一
つ上位のバッファの出力と一つ下位のバッファの出力と
から供給されることを特徴とする請求項１に記載の電池
電圧測定回路。2. A buffer having an input terminal to which the voltage at the connection point of the secondary battery is input and an output terminal connected to the photoMOS relay is further provided, and the operating power source of the buffer is the output of the buffer one level above. The battery voltage measurement circuit according to claim 1, wherein the battery voltage measurement circuit is supplied from the output of the lower buffer and the output of the lower buffer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002084814A JP2003282158A (en) | 2002-03-26 | 2002-03-26 | Battery voltage measuring circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002084814A JP2003282158A (en) | 2002-03-26 | 2002-03-26 | Battery voltage measuring circuit |
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| Publication Number | Publication Date |
|---|---|
| JP2003282158A true JP2003282158A (en) | 2003-10-03 |
Family
ID=29231998
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2002084814A Pending JP2003282158A (en) | 2002-03-26 | 2002-03-26 | Battery voltage measuring circuit |
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| Country | Link |
|---|---|
| JP (1) | JP2003282158A (en) |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007042501A (en) * | 2005-08-04 | 2007-02-15 | Hitachi Ltd | Battery cell voltage measurement device |
| JP2011069639A (en) * | 2009-09-24 | 2011-04-07 | Honda Motor Co Ltd | Voltage detection apparatus |
| JP2011232161A (en) * | 2010-04-27 | 2011-11-17 | Oki Semiconductor Co Ltd | Semiconductor device and monitoring method of battery voltage |
| JP2012078136A (en) * | 2010-09-30 | 2012-04-19 | Lapis Semiconductor Co Ltd | Semiconductor device, and abnormality diagnosis method of booster circuit of semiconductor device |
| JP2013011536A (en) * | 2011-06-30 | 2013-01-17 | Sony Corp | Battery monitor circuit, storage apparatus, electronic apparatus, electric-powered vehicle, and power system |
| JP2014142224A (en) * | 2013-01-23 | 2014-08-07 | Yazaki Corp | Shunt resistance type current sensor |
| JP2016020921A (en) * | 2015-10-05 | 2016-02-04 | ラピスセミコンダクタ株式会社 | Semiconductor device control method |
| JP2016121967A (en) * | 2014-12-25 | 2016-07-07 | ラピスセミコンダクタ株式会社 | Semiconductor device and method for measuring battery voltage |
| US10197635B2 (en) | 2013-06-19 | 2019-02-05 | Yazaki Corporation | Filter circuit |
| JP2020165846A (en) * | 2019-03-29 | 2020-10-08 | ラピスセミコンダクタ株式会社 | Semiconductor device and method for measuring battery voltage |
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2002
- 2002-03-26 JP JP2002084814A patent/JP2003282158A/en active Pending
Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007042501A (en) * | 2005-08-04 | 2007-02-15 | Hitachi Ltd | Battery cell voltage measurement device |
| JP2011069639A (en) * | 2009-09-24 | 2011-04-07 | Honda Motor Co Ltd | Voltage detection apparatus |
| US8786289B2 (en) | 2010-04-27 | 2014-07-22 | Oki Semiconductor Co., Ltd. | Method and semiconductor device for monitoring battery voltages |
| JP2011232161A (en) * | 2010-04-27 | 2011-11-17 | Oki Semiconductor Co Ltd | Semiconductor device and monitoring method of battery voltage |
| JP2012078136A (en) * | 2010-09-30 | 2012-04-19 | Lapis Semiconductor Co Ltd | Semiconductor device, and abnormality diagnosis method of booster circuit of semiconductor device |
| CN102445613A (en) * | 2010-09-30 | 2012-05-09 | 拉碧斯半导体株式会社 | Semiconductor device, and method of diagnosing abnormality of boosting circuit of semiconductor device |
| JP2013011536A (en) * | 2011-06-30 | 2013-01-17 | Sony Corp | Battery monitor circuit, storage apparatus, electronic apparatus, electric-powered vehicle, and power system |
| JP2014142224A (en) * | 2013-01-23 | 2014-08-07 | Yazaki Corp | Shunt resistance type current sensor |
| US10197635B2 (en) | 2013-06-19 | 2019-02-05 | Yazaki Corporation | Filter circuit |
| DE112014002935B4 (en) | 2013-06-19 | 2019-09-12 | Yazaki Corporation | filter circuit |
| JP2016121967A (en) * | 2014-12-25 | 2016-07-07 | ラピスセミコンダクタ株式会社 | Semiconductor device and method for measuring battery voltage |
| JP2016020921A (en) * | 2015-10-05 | 2016-02-04 | ラピスセミコンダクタ株式会社 | Semiconductor device control method |
| JP2020165846A (en) * | 2019-03-29 | 2020-10-08 | ラピスセミコンダクタ株式会社 | Semiconductor device and method for measuring battery voltage |
| JP7315290B2 (en) | 2019-03-29 | 2023-07-26 | ラピスセミコンダクタ株式会社 | Semiconductor device and battery voltage measurement method |
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