JP3420672B2 - Secondary battery protection circuit - Google Patents
Secondary battery protection circuitInfo
- Publication number
- JP3420672B2 JP3420672B2 JP30483996A JP30483996A JP3420672B2 JP 3420672 B2 JP3420672 B2 JP 3420672B2 JP 30483996 A JP30483996 A JP 30483996A JP 30483996 A JP30483996 A JP 30483996A JP 3420672 B2 JP3420672 B2 JP 3420672B2
- Authority
- JP
- Japan
- Prior art keywords
- terminal
- battery
- voltage
- voltage detection
- secondary battery
- 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.)
- Expired - Fee Related
Links
Landscapes
- Protection Of Static Devices (AREA)
- Charge And Discharge Circuits For Batteries Or The Like (AREA)
- Tests Of Electric Status Of Batteries (AREA)
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、二次電池を過充電
や過放電から保護するための保護回路に係り、特に二次
電池の接続外れに対しても二次電池を過充電や過放電か
ら保護できる保護回路に関する。関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protection circuit for protecting a secondary battery from overcharging or overdischarging, and particularly to overcharging or overdischarging the secondary battery even when the secondary battery is disconnected. Protection circuit that can protect from Concerned.
【０００２】[0002]
【従来技術】一般に、リチウム二次電池などの非水溶媒
系二次電池や鉛蓄電池では、充電中に電池電圧が高くな
り過ぎると、電池性能が劣化したり、安全性が損なわれ
るため、充電器側で所定値以上の電圧が発生しないよう
にしている。しかしながら、充電器が壊れた場合、充電
時に二次電池の端子に所定値以上の電圧が加わることを
考慮して、二次電池の電圧を監視し、電池電圧が所定範
囲内となるように充電を制御する必要があった。特に、
リチウム二次電池の場合には、例えば電池電圧が４．５
Ｖ以上になると電解液の分解によりガスが発生し、その
結果電池内部の圧力が上昇して安全弁が作動し、漏液す
ることもあった。そのため、リチウム二次電池を使用す
る場合、電池電圧が上昇して充電禁止電圧に達すると充
電を遮断する機能を有する保護回路を介して充電するこ
とが一般的である。充電禁止電圧は、電解液の分解が始
まる電圧より若干低い電圧（例えば４．３５Ｖ）に設定
される。2. Description of the Related Art Generally, in a non-aqueous solvent type secondary battery such as a lithium secondary battery or a lead storage battery, if the battery voltage becomes too high during charging, the battery performance is deteriorated or the safety is impaired. The voltage on the device side is set so that it does not exceed a specified value. However, if the charger is broken, the voltage of the secondary battery is monitored in consideration of the fact that a voltage higher than the specified value is applied to the terminal of the secondary battery during charging, and the battery voltage is charged within the specified range. Had to control. In particular,
In the case of a lithium secondary battery, for example, the battery voltage is 4.5
If the voltage exceeds V, gas is generated due to decomposition of the electrolytic solution, and as a result, the internal pressure of the battery rises, the safety valve operates, and liquid leakage may occur. Therefore, when a lithium secondary battery is used, it is common to charge the lithium secondary battery via a protection circuit having a function of interrupting charging when the battery voltage rises and reaches the charge inhibition voltage. The charge inhibition voltage is set to a voltage (eg, 4.35 V) that is slightly lower than the voltage at which decomposition of the electrolytic solution starts.
【０００３】また、リチウム二次電池などの非水溶媒系
二次電池や鉛蓄電池は、放電中に電池電圧が低くなり過
ぎた場合でも、電池性能が劣化したり、安全性が損なわ
れるため、負荷である使用機器側で所定値以下の電圧が
発生しないようにしている。しかしながら、使用機器が
壊れた場合、放電時に二次電池が所定値以下の電圧にな
ることを考慮して、二次電池の電圧を監視して電池電圧
が所定範囲内となるように放電を制御する必要があっ
た。特に、リチウム二次電池の場合には、電池電圧が非
回復電圧（例えば１Ｖ）まで放電すると、その後充電し
ても場合によっては全く使用できないことがあった。そ
のため、リチウム二次電池を使用する場合、電池電圧が
低下して放電禁止電圧に達すると放電を遮断する機能を
有する保護回路を介して放電させることが一般的であ
る。放電禁止電圧は、負極の銅が溶解し始める電圧２Ｖ
より若干高い電圧（例えば２．３Ｖ）に設定される。Further, in non-aqueous solvent type secondary batteries such as lithium secondary batteries and lead acid batteries, even if the battery voltage becomes too low during discharging, the battery performance is deteriorated and the safety is impaired. The voltage used is less than a predetermined value on the side of the equipment used, which is the load. However, if the equipment used breaks down, the voltage of the secondary battery will be below a specified value during discharge, and the voltage of the secondary battery will be monitored to control the discharge so that the battery voltage falls within the specified range. Had to do. In particular, in the case of a lithium secondary battery, if the battery voltage is discharged to a non-recovery voltage (for example, 1 V), it may not be used at all even if it is charged thereafter. Therefore, when a lithium secondary battery is used, it is common to discharge the lithium secondary battery through a protection circuit having a function of interrupting the discharge when the battery voltage drops and reaches the discharge inhibition voltage. The discharge inhibition voltage is 2V, at which the negative electrode copper starts to melt.
It is set to a slightly higher voltage (for example, 2.3 V).
【０００４】このような機能を有する従来の保護回路
は、例えば電池電圧を検知する電圧検出回路と、この電
圧検出回路の出力に基づいて充電電流や放電電流の遮断
を行うためのＦＥＴなどの第１および第２のスイッチ素
子からなり、電池電圧が充電禁止電圧に達すると、第１
のスイッチ素子を非導通状態として充電電流を遮断し、
電池電圧が放電禁止電圧に達すると、第２のスイッチ素
子を非導通状態として放電電流を遮断する構成となって
いる。A conventional protection circuit having such a function is, for example, a voltage detection circuit for detecting a battery voltage and a first FET such as an FET for cutting off a charging current or a discharging current based on an output of the voltage detection circuit. When the battery voltage reaches the charge prohibition voltage, the first switch
The switch element is turned off to cut off the charging current,
When the battery voltage reaches the discharge inhibition voltage, the second switch element is made non-conductive to cut off the discharge current.
【０００５】[0005]
【発明が解決しようとする課題】上述した従来の二次電
池の保護回路では、電池電圧が充電禁止電圧に達すると
第１のスイッチ素子を遮断して充電を停止しているが、
何らかの原因で二次電池の中間接続点と保護回路との接
続が外れた場合、電圧検出回路は電池電圧を検知できな
いため、電池電圧が充電禁止電圧に達しても、充電禁止
信号を発生せずに第１のスイッチ素子を遮断することが
できず、充電状態を維持して過充電となってしまうた
め、漏液が生じる場合があった。In the above-mentioned conventional secondary battery protection circuit, when the battery voltage reaches the charge inhibition voltage, the first switch element is cut off to stop charging.
If the secondary battery's intermediate connection point is disconnected from the protection circuit for some reason, the voltage detection circuit cannot detect the battery voltage, so the charge prohibition signal is not generated even when the battery voltage reaches the charge prohibition voltage. In addition, since the first switch element cannot be shut off and the state of charge is maintained to cause overcharge, liquid leakage may occur.
【０００６】また、従来の二次電池の保護回路では、電
池電圧が放電禁止電圧に達すると第２のスイッチ素子を
遮断して放電を停止しているが、何らかの原因で二次電
池の中間接続点と保護回路との接続が外れた場合、電圧
検出回路は電池電圧を検知できないため、電池電圧が放
電禁止電圧に達しても、放電禁止信号を発生せずに第２
のスイッチ素子を遮断できず放電状態を維持して過放電
となってしまうため、その後充電しても場合によっては
全く使用できないことがあった。Further, in the conventional secondary battery protection circuit, when the battery voltage reaches the discharge inhibition voltage, the second switch element is shut off to stop the discharge. If the point and the protection circuit are disconnected, the voltage detection circuit cannot detect the battery voltage. Therefore, even if the battery voltage reaches the discharge inhibition voltage, the discharge inhibition signal is not generated and the second
The switching element cannot be shut off and the discharge state is maintained, resulting in over-discharge, and even if it is subsequently charged, it may not be used at all in some cases.
【０００７】本発明は、二次電池の中間接続点の接続が
外れた場合、その異常発生を検出して過充電や過放電か
ら確実に保護することができる二次電池の保護回路を提
供することを目的とする。The present invention provides a protection circuit for a secondary battery, which can detect the occurrence of an abnormality when the intermediate connection point of the secondary battery is disconnected and reliably protect it from overcharge or overdischarge. The purpose is to
【０００８】[0008]
【課題を解決するための手段】上記の課題を解決するた
め、本発明に係る二次電池の保護回路は、直列に接続さ
れた第１及び第２の二次電池の充放電回路に挿入された
スイッチ素子と、前記第１の二次電池のプラス端子に接
続される第１の電池電圧検出端子、前記第１の二次電池
のマイナス端子及び前記第２の二次電池のプラス端子に
接続される第２の電池電圧検出端子、及び前記第２の二
次電池のマイナス端子に接続される第３の電池電圧検出
端子を有し、前記第１及び第２の二次電池の端子電圧を
前記第１乃至第３の電池電圧検出端子を介して検出し、
該第１及び第２の二次電池の端子電圧の少なくとも一方
が所定の充電禁止電圧まで上昇したとき前記スイッチ素
子を非導通状態にする制御手段と、前記第２の電池電圧
検出端子と該第２の電池電圧検出端子の電位より高い電
位点との間に接続され、前記第１の二次電池のマイナス
端子及び前記第２の二次電池のプラス端子と該第２の電
池電圧検出端子との接続が外れたとき、該第２の電池電
圧検出端子を前記第２の二次電池の端子電圧が前記充電
禁止電圧まで上昇したときと同じ電位状態とするための
プルアップ抵抗とを備えたことを特徴とする。In order to solve the above problems, the protection circuit for a secondary battery according to the present invention is connected in series.
Inserted into the charging / discharging circuit of the first and second secondary batteries
Connect the switch element to the positive terminal of the first secondary battery.
A first battery voltage detection terminal connected to the first secondary battery;
The negative terminal and the positive terminal of the second secondary battery
A second battery voltage detection terminal to be connected, and the second battery
Third battery voltage detection connected to the negative terminal of the secondary battery
Has a terminal, the terminal voltage of the first and second secondary batteries
Detected through the first to third battery voltage detection terminals,
At least one of the terminal voltages of the first and second secondary batteries
When the voltage rises to a specified charge inhibit voltage, the switch element
Control means for bringing the child into a non-conducting state, and the second battery voltage
A voltage higher than the potentials of the detection terminal and the second battery voltage detection terminal.
It is connected between the point and the minus of the first secondary battery.
A terminal, a positive terminal of the second secondary battery, and the second battery.
When the connection with the battery voltage detection terminal is disconnected, the second battery
The pressure detection terminal is charged by the terminal voltage of the second secondary battery.
To maintain the same potential as when the voltage reached the prohibit voltage
It has a pull-up resistor .
【０００９】また、前記第１及び第２の二次電池の端子
電圧の少なくとも一方が前記放電禁止電圧以下に低下し
たとき前記プルアップ抵抗を前記第２の電池電圧検出端
子と該第２の電池電圧検出端子の電位より高い電位点と
の間から切り離す手段をさらに備えたことを特徴とす
る。 Also, the terminals of the first and second secondary batteries
At least one of the voltage drops below the discharge inhibit voltage
When the pull-up resistor is connected to the second battery voltage detecting end,
And a potential point higher than the potential of the second battery voltage detection terminal
Characterized by further comprising means for separating from
It
【００１０】本発明に係る他の二次電池の保護回路は、
直列に接続された第１及び第２の二次電池の充放電回路
に挿入されたスイッチ素子と、前記第１の二次電池のプ
ラス端子に接続される第１の電池電圧検出端子、前記第
１の二次電池のマイナス端子及び前記第２の二次電池の
プラス端子に接続される第２の電池電圧検出端子、及び
前記第２の二次電池のマイナス端子に接続される第３の
電池電圧検出端子を有し、前記第１及び第２の二次電池
の端子電圧を前記第１乃至第３の電池電圧検出端子を介
して検出し、該第１及び第２の二次電池の端子電圧の少
なくとも一方が所定の放電禁止電圧まで低下したとき前
記スイッチ素子を非導通状態にする制御手段と、前記第
２の電池電圧検出端子と該第２の電池電圧検出端子の電
位より低い電位点との間に接続され、前記第１の二次電
池のマイナス端子及び前記第２の二次電池のプラス端子
と該第２の電池電圧検出端子との接続が外れたとき、該
第２の電池電圧検出端子を前記第２の二次電池の端子電
圧が前記放電禁止電圧まで低下したときと同じ電位状態
とするためのプルダウン抵抗と、前記第１及び第２の二
次電池の端子電圧の少なくとも一方が前記放電禁止電圧
以下に低下したとき前記プルダウン抵抗を前記第２の電
池電圧検出端子と該第２の電池電圧検出端子の電位より
高い電位点との間から切り離す手段とを備えたことを特
徴とする。 Another secondary battery protection circuit according to the present invention is
Charging / discharging circuit for first and second secondary batteries connected in series
Switch element inserted in the first secondary battery
A first battery voltage detection terminal connected to the lath terminal,
The negative terminal of the secondary battery of No. 1 and the secondary battery of the second
A second battery voltage detection terminal connected to the positive terminal, and
A third terminal connected to the negative terminal of the second secondary battery
The first and second secondary batteries having a battery voltage detection terminal
Through the first to third battery voltage detection terminals
Detected and the terminal voltage of the first and second secondary batteries is low.
At least when one of them has dropped to the specified discharge inhibit voltage
A control means for bringing the switch element into a non-conducting state;
Of the second battery voltage detection terminal and the second battery voltage detection terminal
Connected to a potential point lower than the
Negative terminal of the pond and positive terminal of the second secondary battery
And the second battery voltage detection terminal is disconnected,
The second battery voltage detection terminal is connected to the terminal voltage of the second secondary battery.
The same potential as when the voltage dropped to the discharge inhibit voltage
And a pull-down resistor for
At least one of the terminal voltage of the secondary battery is the discharge inhibit voltage
When the voltage drops below, the pull-down resistance is changed to the second voltage.
From the potential of the battery voltage detection terminal and the second battery voltage detection terminal
It is characterized in that it is provided with means for disconnecting from a high potential point.
To collect.
【００１１】[0011]
【００１２】[0012]
【００１３】また、二次電池の端子電圧が放電禁止電圧
まで低下したときには、プルアップ抵抗やプルダウン抵
抗を切り離すことにより、これらの抵抗での電流消費に
よる過放電を防止することが可能となる。 Further, when the terminal voltage of the secondary battery has decreased to the discharge prohibition voltage, by decouple the pull-up or pull-down resistors, it is possible to prevent excessive discharge due to current consumption in these resistors Become.
【００１４】[0014]
【発明の実施の形態】以下、本発明の実施形態を図面を
参照して説明する。
（第１の実施形態）図１は、本発明の一実施形態に係る
二次電池の保護回路を示す図である。保護対象となる二
次電池（以下、単に電池という）１、２は、例えばリチ
ウム電池等の非水溶媒系二次電池や鉛蓄電池など定電圧
で充電する電池であり、以下では電池１、２がリチウム
二次電池の場合を例にとって説明する。DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 is a diagram showing a protection circuit for a secondary battery according to an embodiment of the present invention. Secondary batteries (hereinafter, simply referred to as batteries) 1 and 2 to be protected are batteries that are charged with a constant voltage, such as non-aqueous solvent secondary batteries such as lithium batteries and lead storage batteries. Will be described as an example.
【００１５】電池１、２は直列に接続されており、その
充放電回路には直列にスイッチ素子を構成するＮＰＮ型
の第１および第２の電界効果型トランジスタ（以下、Ｆ
ＥＴという）３、４が接続されている。具体的には、第
１のＦＥＴ３のソース端子は電池２のマイナス端子に接
続され、第１のＦＥＴ３のドレイン端子は第２のＦＥＴ
４のドレイン端子に接続されている。The batteries 1 and 2 are connected in series, and the charge / discharge circuit thereof has NPN type first and second field effect transistors (hereinafter, referred to as F
3 and 4 are connected. Specifically, the source terminal of the first FET 3 is connected to the negative terminal of the battery 2, and the drain terminal of the first FET 3 is the second FET.
4 is connected to the drain terminal.
【００１６】第１のＦＥＴ３には、寄生ダイオードＤ３
が図１に示すように充電時に順方向になるように並列に
接続されており、第２のＦＥＴ４には寄生ダイオードＤ
４が図１に示すように放電時に順方向になるように並列
に接続されている。The first FET 3 has a parasitic diode D3
Are connected in parallel so as to be in the forward direction during charging as shown in FIG. 1, and the parasitic diode D is connected to the second FET 4.
4 are connected in parallel so as to be in the forward direction during discharge as shown in FIG.
【００１７】電池１のプラス端子は外部接続端子である
プラス端子（＋）に、第２のＦＥＴ４のソース端子は外
部接続端子であるマイナス端子（一）にそれぞれ接続さ
れている。外部接続端子（＋）、（−）間には、充電時
には充電器が接続され、放電時には負荷が接続される。The positive terminal of the battery 1 is connected to a positive terminal (+) which is an external connection terminal, and the source terminal of the second FET 4 is connected to a negative terminal (one) which is an external connection terminal. A charger is connected between the external connection terminals (+) and (-) during charging, and a load is connected during discharging.
【００１８】過充放電防止回路５は、電池電圧検出端子
ａ、ｂを介して電池１の端子電圧、電池電圧検出端子
ｂ、ｃを介して電池２の端子電圧をそれぞれ監視し、い
ずれかの端子電圧が充電時に所定の充電禁止電圧を越え
ると充電禁止出力を発生する過充電防止回路と、放電時
に所定の放電禁止電圧を越えると放電禁止出力を発生す
る過放電防止回路とからなる。The overcharge / discharge prevention circuit 5 monitors the terminal voltage of the battery 1 via the battery voltage detection terminals a and b, and the terminal voltage of the battery 2 via the battery voltage detection terminals b and c, respectively. Overcharge prevention circuit that generates a charge inhibition output when the terminal voltage exceeds a predetermined charge inhibition voltage during charging, and an overdischarge prevention circuit that generates a discharge inhibition output when the terminal voltage exceeds a predetermined discharge inhibition voltage during discharging Consists of.
【００１９】すなわち、過充放電防止回路５の電池電圧
検出端子ａは電池１のプラス端子に、電池電圧検出端子
ｂは電池１のマイナス端子と電池２のプラス端子に、電
池電圧検出端子ｃは電池２のマイナス端子にそれぞれ接
続され、電池１、２のいずれかの端子電圧が所定の充電
禁止電圧に達すると、過充放電防止回路５が充電禁止出
力を発生し、過充放電防止回路５の出力端子ｅを高レベ
ルから低レベルにする。また、電池１、２のいずれかの
端子電圧が所定の放電禁止電圧に達すると、過充放電防
止回路５が放電禁止出力を発生し、過充放電防止回路５
の出力端子ｄを高レベルから低レベルにする。That is, the battery voltage detection terminal a of the overcharge / discharge prevention circuit 5 is the plus terminal of the battery 1, the battery voltage detection terminal b is the minus terminal of the battery 1 and the plus terminal of the battery 2, and the battery voltage detection terminal c is When the terminal voltage of one of the batteries 1 and 2 connected to the negative terminal of the battery 2 reaches a predetermined charge inhibition voltage, the overcharge / discharge prevention circuit 5 generates a charge inhibition output, and the overcharge / discharge prevention circuit 5 The output terminal e of is changed from the high level to the low level. When the terminal voltage of one of the batteries 1 and 2 reaches a predetermined discharge inhibition voltage, the overcharge / discharge prevention circuit 5 generates a discharge inhibition output, and the overcharge / discharge prevention circuit 5
The output terminal d of is changed from the high level to the low level.
【００２０】電池１のプラス端子と電池電圧検出端子で
ある電池電圧検出端子ｂの間には、異常発生検出手段で
あるプルアップ抵抗６が接続されている。従って、何ら
かの原因で電池１、２の中間接続点と電池電圧検出端子
ｂとの接続が外れると、電池電圧検出端子ｂはプルアッ
プ抵抗６により電池１のプラス端子とほぼ同電位とな
る。A pull-up resistor 6 as an abnormality occurrence detecting means is connected between the positive terminal of the battery 1 and the battery voltage detecting terminal b which is a battery voltage detecting terminal. Therefore, if the connection between the intermediate connection point of the batteries 1 and 2 and the battery voltage detection terminal b is disconnected for some reason, the battery voltage detection terminal b becomes approximately the same potential as the plus terminal of the battery 1 due to the pull-up resistor 6.
【００２１】次に、図１の電池の保護回路の動作を説明
する。まず、電池１、２の端子電圧がいずれも充電禁止
電圧と放電禁止電圧との間にあるときは、過充放電防止
回路５の出力端子ｄ、ｅはいずれも高レベルとなるの
で、第１、第２のＦＥＴ３、４はいずれも導通状態とな
り、充放電は正常に行われる。Next, the operation of the battery protection circuit shown in FIG. 1 will be described. First, when the terminal voltages of the batteries 1 and 2 are both between the charge prohibition voltage and the discharge prohibition voltage, the output terminals d and e of the overcharge / discharge prevention circuit 5 are both at the high level. , The second FETs 3 and 4 are both in a conductive state, and charging / discharging is normally performed.
【００２２】外部接続端子（＋），（−）に接続される
充電器は、電池１個当たりの充電電圧が過充放電防止回
路５に設定された所定の充電禁止電圧より低い電圧とな
るように充電を行うため、通常は電池１、２の端子電圧
はいずれも所定の充電禁止電圧より低く、過充放電防止
回路５の出力端子ｅは高レベルとなり、第２のＦＥＴ４
は導通状態を維持する。The charger connected to the external connection terminals (+) and (-) has a charging voltage per battery lower than a predetermined charging inhibition voltage set in the overcharge / discharge prevention circuit 5. In order to charge the battery, the terminal voltages of the batteries 1 and 2 are usually lower than a predetermined charge inhibition voltage, the output terminal e of the overcharge / discharge prevention circuit 5 becomes high level, and the second FET 4
Maintains continuity.
【００２３】これに対して、充電器の故障などにより充
電電圧が高くなって、電池１、２のいずれか一方または
両方が所定の充電禁止電圧を越えると、過充放電防止回
路５の出力端子ｅは低レベルとなり、第２のＦＥＴ４は
非導通状態となるために、充電が停止され、電池の過充
電が防止される。On the other hand, when the charging voltage becomes high due to a failure of the charger or the like, and one or both of the batteries 1 and 2 exceed a predetermined charge inhibition voltage, the output terminal of the overcharge / discharge prevention circuit 5 Since e becomes low level and the second FET 4 becomes non-conductive, charging is stopped and overcharging of the battery is prevented.
【００２４】一方、放電時に電池１、２のいずれか一方
または両方の端子電圧が低下し、放電禁止電圧より低く
なると、過充放電防止回路５の出力端子ｄは低レベルと
なり、第１のＦＥＴ３は非導通状態となるために、放電
が停止され、電池の過放電が防止される。On the other hand, when the terminal voltage of one or both of the batteries 1 and 2 drops during discharging and becomes lower than the discharge inhibition voltage, the output terminal d of the overcharge / discharge prevention circuit 5 becomes low level and the first FET 3 Is in a non-conductive state, the discharge is stopped and the battery is prevented from being over-discharged.
【００２５】ここで、何らかの原因によって電池１、２
の中間接続点と過充放電防止回路５の電池電圧検出端子
ｂとの接続が外れた場合、電池電圧検出端子ｂはプルア
ップ抵抗６によって電池１のプラス端子とほぼ同電位と
なり、電池１、２の端子電圧の和が電池電圧検出端子ｂ
と電池電圧検出端子ｃとの間に印加される。電池１、２
の端子電圧の和は通常、充電禁止電圧を越えるため、過
充放電防止回路５の出力端子ｅは低レベルとなり、第２
のＦＥＴ４は非導通状態となるために、充電が停止さ
れ、電池の過充電が防止される。Here, for some reason, the batteries 1 and 2 are
When the intermediate connection point of and the battery voltage detection terminal b of the overcharge / discharge prevention circuit 5 are disconnected, the battery voltage detection terminal b becomes almost the same potential as the positive terminal of the battery 1 by the pull-up resistor 6, and the battery 1, The sum of the terminal voltages of 2 is the battery voltage detection terminal b
And a battery voltage detection terminal c. Batteries 1 and 2
Since the sum of the terminal voltages of the above normally exceeds the charge prohibition voltage, the output terminal e of the overcharge / discharge prevention circuit 5 becomes low level,
Since the FET 4 is turned off, charging is stopped and overcharging of the battery is prevented.
【００２６】（第２の実施形態）図２に、本発明の第２
の実施形態に係る二次電池の保護回路を示す。本実施形
態は、図１の保護回路におけるプルアップ抵抗６に直列
にプルアップ抵抗遮断スイッチであるトランジスタ７を
接続した構成となっている。すなわち、プルアップ抵抗
６は電池１のプラス端子とスイッチ素子であるトランジ
スタ７のコレクタとの間に接続され、トランジスタ７の
エミッタは電池電圧検出端子ｂに、トランジスタ７のベ
ースは出力端子ｄに接続されている。(Second Embodiment) FIG. 2 shows a second embodiment of the present invention.
2 shows a protection circuit for a secondary battery according to the embodiment. In this embodiment, the pull-up resistor 6 in the protection circuit of FIG. 1 is connected in series with a transistor 7 which is a pull-up resistor cutoff switch. That is, the pull-up resistor 6 is connected between the positive terminal of the battery 1 and the collector of the transistor 7, which is a switching element, the emitter of the transistor 7 is connected to the battery voltage detection terminal b, and the base of the transistor 7 is connected to the output terminal d. Has been done.
【００２７】電池１、２の端子電圧がいずれも充電禁止
電圧と放電禁止電圧の間にあるときは、過充放電防止回
路５の出力端子ｄ、ｅはいずれも高レベルとなり、第
１、第２のＦＥＴ３、４はいずれも導通状態となるた
め、充放電は正常に行われる。このとき、過充放電防止
回路５の出力端子ｄが高レベルなので、トランジスタ７
は導通状態となっている。When the terminal voltages of the batteries 1 and 2 are both between the charge inhibition voltage and the discharge inhibition voltage, the output terminals d and e of the overcharge / discharge prevention circuit 5 are both at the high level, and the first and the first Since the second FETs 3 and 4 are both in a conductive state, charging / discharging is normally performed. At this time, since the output terminal d of the overcharge / discharge prevention circuit 5 is at a high level, the transistor 7
Is conducting.
【００２８】ここで、何らかの原因によって電池１、２
の中間接続点と過充放電防止回路５の電池電圧検出端子
ｂとの接続が外れた場合、電池電圧検出端子ｂはプルア
ップ抵抗６によって電池１のプラス端子とほぼ同電位と
なり、電池１、２の端子電圧の和が電池電圧検出端子ｂ
と電池電圧検出端子ｃとの間に印加される。電池１、２
の端子電圧の和は通常、充電禁止電圧を越えるため、過
充放電防止回路５の出力端子ｅは低レベルとなり、第２
のＦＥＴ４は非導通状態となるために、充電が停止さ
れ、電池の過充電が防止される。Here, for some reason, the batteries 1 and 2 are
When the intermediate connection point of and the battery voltage detection terminal b of the overcharge / discharge prevention circuit 5 are disconnected, the battery voltage detection terminal b becomes almost the same potential as the positive terminal of the battery 1 by the pull-up resistor 6, and the battery 1, The sum of the terminal voltages of 2 is the battery voltage detection terminal b
And a battery voltage detection terminal c. Batteries 1 and 2
Since the sum of the terminal voltages of the above normally exceeds the charge prohibition voltage, the output terminal e of the overcharge / discharge prevention circuit 5 becomes low level,
Since the FET 4 is turned off, charging is stopped and overcharging of the battery is prevented.
【００２９】そして、電池１、２のいずれか一方または
両方の端子電圧が放電禁止電圧より低くなると、過充電
放電防止回路５の出力端子ｄは低レベルとなり、トラン
ジスタ７は非導通状態となるため、プルアップ抵抗６に
は電流が流れなくなる。When the terminal voltage of one or both of the batteries 1 and 2 becomes lower than the discharge inhibition voltage, the output terminal d of the overcharge / discharge prevention circuit 5 becomes low level and the transistor 7 becomes non-conductive. , No current flows through the pull-up resistor 6.
【００３０】このように本実施形態によれば、先の実施
形態に加えて、電池１、２のいずれか一方または両方の
端子電圧が放電禁止電圧以下のときは、プルアップ抵抗
６での電池１の電流の消費が防止され、電池の過放電を
防止することができるという効果が得られる。As described above, according to this embodiment, in addition to the above embodiment, when the terminal voltage of one or both of the batteries 1 and 2 is equal to or lower than the discharge inhibition voltage, the battery with the pull-up resistor 6 is used. It is possible to obtain the effect that the current consumption of No. 1 is prevented and the battery is prevented from being over-discharged.
【００３１】（第３の実施形態）図３は、本発明の他の
実施形態に係る二次電池の保護回路を示す図であり、プ
ルアップ遮断スイッチとして、先の実施形態におけるト
ランジスタ７に代えてスイッチ回路１１を用いている。
このスイッチ回路１１は、プルアップ抵抗６に直列に接
続された第１のトランジスタ７と、コレクタが抵抗９を
介してトランジスタ７のベースに接続され、エミッタが
電圧検出端子ｃに接続され、ベースが抵抗１０を介して
出力端子ｄに接続された第２のトランジスタ８により構
成される。(Third Embodiment) FIG. 3 is a diagram showing a protection circuit for a secondary battery according to another embodiment of the present invention. Instead of the transistor 7 in the previous embodiment, a pull-up cutoff switch is used. Switch circuit 11 is used.
This switch circuit 11 has a first transistor 7 connected in series to a pull-up resistor 6, a collector connected to the base of the transistor 7 via a resistor 9, an emitter connected to a voltage detection terminal c, and a base connected to the voltage detection terminal c. The second transistor 8 is connected to the output terminal d via the resistor 10.
【００３２】本実施形態によると、出力端子ｄの高レベ
ル時の電位が比較的低い場合でも、トランジスタ９が確
実にオンとなり、従ってトランジスタ７も確実にオンと
なるため、確実な動作を得ることができる。According to this embodiment, even when the potential of the output terminal d at the high level is relatively low, the transistor 9 is surely turned on, and thus the transistor 7 is reliably turned on, so that a reliable operation is obtained. You can
【００３３】以上本発明の実施形態について説明した
が、本発明は上記実施形態に限定されるものでなく、次
のように種々変形して実施することができる。
（１）上記実施形態では、異常発生検出手段として電圧
検出端子ｂと電圧検出端子ｂの電位より高い電位点（上
記実施形態では電池１のプラス端子）との間に接続した
プルアップ抵抗６を用いた例について説明したが、例え
ば電圧検出端子ｂと電圧検出端子ｂの電位より低い電位
点との間に接続したプルダウン抵抗を用いてもよい。こ
の場合には、例えば電池１、２の中間接続点と電圧検出
端子ｂとの接続が外れると、電池電圧検出端子ｂ、ｃ間
の電圧が放電禁止電圧以下となって、出力端子ｄが低レ
ベルとなり、第１のＦＥＴ３が非導通状態となることに
よって放電が禁止されため、電池の過放電が防止される
ことになる。Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made as follows. (1) In the above embodiment, the pull-up resistor 6 connected between the voltage detection terminal b and the potential point higher than the potential of the voltage detection terminal b (the positive terminal of the battery 1 in the above embodiment) is used as the abnormality occurrence detection means. Although the example of use has been described, for example, a pull-down resistor connected between the voltage detection terminal b and a potential point lower than the potential of the voltage detection terminal b may be used. In this case, for example, when the connection between the intermediate connection point of the batteries 1 and 2 and the voltage detection terminal b is disconnected, the voltage between the battery voltage detection terminals b and c becomes equal to or lower than the discharge inhibition voltage and the output terminal d becomes low. When the level becomes the level and the first FET 3 is in the non-conducting state, the discharge is prohibited, and the over-discharge of the battery is prevented.
【００３４】（２）また、このようにプルダウン抵抗を
用いる場合においても、第２および第３の実施形態にお
けるプルアップ抵抗遮断スイッチを用いたと同様に、電
池の端子電圧が放電禁止電圧まで低下したときに電池電
圧検出端子ｂとプルダウン抵抗とを切り離すプルダウン
抵抗遮断スイッチを設け、電池の端子電圧が放電禁止電
圧以下のときのプルダウン抵抗での電流の消費による電
池の過放電を防止するようにすることができる。(2) Further, even when the pull-down resistor is used in this way, the terminal voltage of the battery is reduced to the discharge inhibition voltage as in the case of using the pull-up resistor cutoff switch in the second and third embodiments. At this time, a pull-down resistor cutoff switch for disconnecting the battery voltage detection terminal b from the pull-down resistor is provided to prevent over-discharge of the battery due to current consumption in the pull-down resistor when the terminal voltage of the battery is equal to or lower than the discharge inhibition voltage. be able to.
【００３５】（３）上記実施形態では、定電圧で充電す
る電池として非水溶媒系電池を例にとり説明したが、鉛
蓄電池でもよく他の電池でも良い。
（４）上記実施形態では、電池を２個直列接続した場合
について説明したが、さらに多数直列接続した場合にも
適用でき、また電池を複数個並列接続したセルブロック
を複数個直列接続した場合にも適用できる。(3) In the above embodiment, the non-aqueous solvent type battery is described as an example of the battery charged at a constant voltage, but a lead storage battery or another battery may be used. (4) In the above embodiment, the case where two batteries are connected in series has been described, but the present invention is also applicable to a case where a larger number of cells are connected in series, and when a plurality of cell blocks in which a plurality of batteries are connected in parallel are connected in series. Can also be applied.
【００３６】（５）上記実施形態では、第１、第２のス
イッチ素子であるＦＥＴ３、４を電池２のマイナス端子
側に接続した例で説明したが、電池１のプラス端子側に
接続してもよい。
（６）上記実施形態で説明した保護以外に、ＰＴＣやサ
ーモスタットあるいは温度ヒューズなどの保護素子を充
放電回路に挿入してもよい。(5) In the above embodiment, the FETs 3 and 4 as the first and second switching elements are connected to the negative terminal side of the battery 2, but the positive terminal side of the battery 1 is connected. Good. (6) In addition to the protection described in the above embodiment, a protective element such as PTC, thermostat, or temperature fuse may be inserted in the charge / discharge circuit.
【００３７】[0037]
【発明の効果】以上説明したように、本発明の二次電池
の保護回路によれば、何らかの原因により電池と電池電
圧検出端子との接続が外れた場合においても、異常発生
検出手段により充電または放電を遮断することができ、
従来の保護回路よりさらに安全性を向上させることが可
能となる。As described above, according to the secondary battery protection circuit of the present invention, even when the battery and the battery voltage detection terminal are disconnected from each other for some reason, the abnormality occurrence detection means charges or Can interrupt the discharge,
It is possible to further improve the safety as compared with the conventional protection circuit.
【００３８】[0038]
【図１】本発明の第１の実施形態に係る二次電池の保護
回路の構成を示すブロック図FIG. 1 is a block diagram showing a configuration of a protection circuit for a secondary battery according to a first embodiment of the present invention.
【図２】本発明の第２の実施形態に係る二次電池の保護
回路の構成を示すブロック図FIG. 2 is a block diagram showing a configuration of a protection circuit for a secondary battery according to a second embodiment of the present invention.
【図３】本発明の第３の実施形態に係る二次電池の保護
回路の構成を示すブロック図FIG. 3 is a block diagram showing a configuration of a protection circuit for a secondary battery according to a third embodiment of the present invention.
１、２…二次電池 ３、４…第１、第２のＦＥＴ（スイッチ素子） ５…過充放電防止回路 ６…プルアップ抵抗 ７…第１のトランジスタ ８…第２のトランジスタ ９、１０…抵抗 １１…スイッチ回路 1, 2 ... Secondary battery 3, 4 ... First and second FET (switch element) 5 ... Overcharge / discharge prevention circuit 6 ... pull-up resistor 7 ... first transistor 8 ... second transistor 9, 10 ... resistance 11 ... Switch circuit
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平７−105986（ＪＰ，Ａ) 特開 平６−105457（ＪＰ，Ａ) 特開 平７−23532（ＪＰ，Ａ) 特開 平８−265985（ＪＰ，Ａ) 特開 平８−103027（ＪＰ，Ａ) 実開 昭62−173077（ＪＰ，Ｕ) (58)調査した分野(Int.Cl.7，ＤＢ名) H02H 7/18 H02J 7/00 G01R 31/36 H02M 10/42 - 10/48 ─────────────────────────────────────────────────── --- Continuation of front page (56) Reference JP-A-7-105986 (JP, A) JP-A-6-105457 (JP, A) JP-A-7-23532 (JP, A) JP-A-8- 265985 (JP, A) JP-A-8-103027 (JP, A) Actual development Sho 62-173077 (JP, U) (58) Fields investigated (Int.Cl. 7 , DB name) H02H 7/18 H02J 7 / 00 G01R 31/36 H02M 10/42-10/48
Claims (3)
の充放電回路に挿入されたスイッチ素子と、 前記第１の二次電池のプラス端子に接続される第１の電
池電圧検出端子、前記第１の二次電池のマイナス端子及
び前記第２の二次電池のプラス端子に接続される第２の
電池電圧検出端子、及び前記第２の二次電池のマイナス
端子に接続される第３の電池電圧検出端子を有し、前記
第１及び第２の二次電池の端子電圧を前記第１乃至第３
の電池電圧検出端子を介して検出し、該第１及び第２の
二次電池の端子電圧の少なくとも一方が所定の充電禁止
電圧まで上昇したとき前記スイッチ素子を非導通状態に
する制御手段と、 前記第２の電池電圧検出端子と該第２の電池電圧検出端
子の電位より高い電位点との間に接続され、前記第１の
二次電池のマイナス端子及び前記第２の二次電池のプラ
ス端子と該第２の電池電圧検出端子との接続が外れたと
き、該第２の電池電圧検出端子を前記第２の二次電池の
端子電圧が前記充電禁止電圧まで上昇したときと同じ電
位状態とするためのプルアップ抵抗とを備えたことを特
徴とする二次電池の保護回路。1. A switch element inserted in a charging / discharging circuit of first and second secondary batteries connected in series, and a first battery voltage connected to a positive terminal of the first secondary battery. A detection terminal, a second battery voltage detection terminal connected to the negative terminal of the first secondary battery and a positive terminal of the second secondary battery, and a negative terminal of the second secondary battery A third battery voltage detection terminal, and outputs the terminal voltages of the first and second secondary batteries to the first to third batteries.
A control means for detecting the voltage through the battery voltage detection terminal of the first and second secondary batteries to bring the switch element into a non-conducting state when at least one of the terminal voltages of the first and second secondary batteries rises to a predetermined charge inhibition voltage; It is connected between the second battery voltage detection terminal and a potential point higher than the potential of the second battery voltage detection terminal, and the minus terminal of the first secondary battery and the plus terminal of the second secondary battery. When the terminal is disconnected from the second battery voltage detection terminal, the second battery voltage detection terminal has the same potential state as when the terminal voltage of the second secondary battery rises to the charge inhibition voltage. A protection circuit for a secondary battery, comprising: a pull-up resistor for
の充放電回路に挿入されたスイッチ素子と、 前記第１の二次電池のプラス端子に接続される第１の電
池電圧検出端子、前記第１の二次電池のマイナス端子及
び前記第２の二次電池のプラス端子に接続される第２の
電池電圧検出端子、及び前記第２の二次電池のマイナス
端子に接続される第３の電池電圧検出端子を有し、前記
第１及び第２の二次電池の端子電圧を前記第１乃至第３
の電池電圧検出端子を介して検出し、該第１及び第２の
二次電池の端子電圧の少なくとも一方が所定の充電禁止
電圧まで上昇したとき前記スイッチ素子を非導通状態に
する制御手段と、 前記第２の電池電圧検出端子と該第２の電池電圧検出端
子の電位より高い電位点との間に接続され、前記第１の
二次電池のマイナス端子及び前記第２の二次電池のプラ
ス端子と該第２の電池電圧検出端子との接続が外れたと
き、該第２の電池電圧検出端子を前記第２の二次電池の
端子電圧が前記充電禁止電圧まで上昇したときと同じ電
位状態とするためのプルアップ抵抗と、 前記第１及び第２の二次電池の端子電圧の少なくとも一
方が前記放電禁止電圧以下に低下したとき前記プルアッ
プ抵抗を前記第２の電池電圧検出端子と該第２の電池電
圧検出端子の電位より高い電位点との間から切り離す手
段とを備えたことを特徴とする二次電池の保護回路。2. A switch element inserted in a charge / discharge circuit of the first and second secondary batteries connected in series, and a first battery voltage connected to a positive terminal of the first secondary battery. A detection terminal, a second battery voltage detection terminal connected to the negative terminal of the first secondary battery and a positive terminal of the second secondary battery, and a negative terminal of the second secondary battery A third battery voltage detection terminal, and outputs the terminal voltages of the first and second secondary batteries to the first to third batteries.
A control means for detecting the voltage through the battery voltage detection terminal of the first and second secondary batteries to bring the switch element into a non-conducting state when at least one of the terminal voltages of the first and second secondary batteries rises to a predetermined charge inhibition voltage; It is connected between the second battery voltage detection terminal and a potential point higher than the potential of the second battery voltage detection terminal, and the minus terminal of the first secondary battery and the plus terminal of the second secondary battery. When the terminal is disconnected from the second battery voltage detection terminal, the second battery voltage detection terminal has the same potential state as when the terminal voltage of the second secondary battery rises to the charge inhibition voltage. And a pull-up resistor for setting the pull-up resistor to the second battery voltage detection terminal when at least one of the terminal voltages of the first and second secondary batteries drops below the discharge inhibition voltage. Of the second battery voltage detection terminal Protection circuit of a secondary battery characterized by comprising a means for disconnecting from between the higher potential point than position.
の充放電回路に挿入されたスイッチ素子と、 前記第１の二次電池のプラス端子に接続される第１の電
池電圧検出端子、前記第１の二次電池のマイナス端子及
び前記第２の二次電池のプラス端子に接続される第２の
電池電圧検出端子、及び前記第２の二次電池のマイナス
端子に接続される第３の電池電圧検出端子を有し、前記
第１及び第２の二次電池の端子電圧を前記第１乃至第３
の電池電圧検出端子を介して検出し、該第１及び第２の
二次電池の端子電圧の少なくとも一方が所定の放電禁止
電圧まで低下したとき前記スイッチ素子を非導通状態に
する制御手段と、 前記第２の電池電圧検出端子と該第２の電池電圧検出端
子の電位より低い電位点との間に接続され、前記第１の
二次電池のマイナス端子及び前記第２の二次電池のプラ
ス端子と該第２の電池電圧検出端子との接続が外れたと
き、該第２の電池電圧検出端子を前記第２の二次電池の
端子電圧が前記放電禁止電圧まで低下したときと同じ電
位状態とするためのプルダウン抵抗と、 前記第１及び第２の二次電池の端子電圧の少なくとも一
方が前記放電禁止電圧以下に低下したとき前記プルダウ
ン抵抗を前記第２の電池電圧検出端子と該第２の電池電
圧検出端子の電位より高い電位点との間から切り離す手
段とを備えたことを特徴とする二次電池の保護回路。3. A switch element inserted in a charge / discharge circuit of the first and second secondary batteries connected in series, and a first battery voltage connected to a positive terminal of the first secondary battery. A detection terminal, a second battery voltage detection terminal connected to the negative terminal of the first secondary battery and a positive terminal of the second secondary battery, and a negative terminal of the second secondary battery A third battery voltage detection terminal, and outputs the terminal voltages of the first and second secondary batteries to the first to third batteries.
A control means for detecting the voltage through the battery voltage detection terminal, and bringing the switch element into a non-conducting state when at least one of the terminal voltages of the first and second secondary batteries has dropped to a predetermined discharge inhibition voltage; It is connected between the second battery voltage detection terminal and a potential point lower than the potential of the second battery voltage detection terminal, the negative terminal of the first secondary battery and the positive terminal of the second secondary battery. When the connection between the terminal and the second battery voltage detection terminal is disconnected, the second battery voltage detection terminal has the same potential state as when the terminal voltage of the second secondary battery drops to the discharge inhibition voltage. And a pull-down resistance for reducing the voltage of at least one of the terminal voltages of the first and second secondary batteries to the discharge inhibition voltage or lower. Of the battery voltage detection terminal of Protection circuit of a secondary battery characterized by comprising a means for disconnecting from between the higher potential point than position.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30483996A JP3420672B2 (en) | 1996-11-15 | 1996-11-15 | Secondary battery protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30483996A JP3420672B2 (en) | 1996-11-15 | 1996-11-15 | Secondary battery protection circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH10150721A JPH10150721A (en) | 1998-06-02 |
| JP3420672B2 true JP3420672B2 (en) | 2003-06-30 |
Family
ID=17937893
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30483996A Expired - Fee Related JP3420672B2 (en) | 1996-11-15 | 1996-11-15 | Secondary battery protection circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3420672B2 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3043704B2 (en) * | 1998-03-02 | 2000-05-22 | 米沢日本電気株式会社 | Overcharge / discharge prevention control method and apparatus for battery pack |
| KR100750295B1 (en) | 2006-03-30 | 2007-08-21 | 주식회사 비츠로셀 | Battery protection circuit |
| JP5113741B2 (en) | 2006-04-13 | 2013-01-09 | パナソニック株式会社 | Battery pack and disconnection detection method thereof |
| JP5469813B2 (en) | 2008-01-29 | 2014-04-16 | 株式会社日立製作所 | Battery system for vehicles |
| JP5965017B2 (en) * | 2013-03-18 | 2016-08-03 | 株式会社日立製作所 | Battery system and battery monitoring device |
| US8717035B2 (en) * | 2009-12-23 | 2014-05-06 | Black & Decker Inc. | Systems and methods for detecting an open cell tap in a battery pack |
| KR101093888B1 (en) | 2009-12-28 | 2011-12-13 | 삼성에스디아이 주식회사 | Battery pack and method of detecting line open thereof |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62173077U (en) * | 1986-04-22 | 1987-11-04 | ||
| JP3277565B2 (en) * | 1992-09-17 | 2002-04-22 | ソニー株式会社 | Battery protection circuit |
| JP3121963B2 (en) * | 1993-06-30 | 2001-01-09 | 太陽誘電株式会社 | battery pack |
| JP3249261B2 (en) * | 1993-09-30 | 2002-01-21 | 三洋電機株式会社 | Battery pack |
| JPH08103027A (en) * | 1994-09-30 | 1996-04-16 | Sony Corp | Detector for battery pack state |
| JP3426778B2 (en) * | 1995-03-23 | 2003-07-14 | 三洋電機株式会社 | Battery charge / discharge control method |
-
1996
- 1996-11-15 JP JP30483996A patent/JP3420672B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH10150721A (en) | 1998-06-02 |
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