JP2000278869A - Secondary battery charging circuit, charger, and electric apparatus - Google Patents
Secondary battery charging circuit, charger, and electric apparatusInfo
- Publication number
- JP2000278869A JP2000278869A JP11083133A JP8313399A JP2000278869A JP 2000278869 A JP2000278869 A JP 2000278869A JP 11083133 A JP11083133 A JP 11083133A JP 8313399 A JP8313399 A JP 8313399A JP 2000278869 A JP2000278869 A JP 2000278869A
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- Prior art keywords
- charging current
- charging
- circuit
- voltage
- current
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- Charge And Discharge Circuits For Batteries Or The Like (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】この発明は、リチウムイオン
２次電池やリチウムポリマー２次電池等の２次電池用の
充電回路と、それを備えた充電器および電気機器に関す
るものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging circuit for a secondary battery such as a lithium ion secondary battery or a lithium polymer secondary battery, and a charger and an electric device having the same.
【０００２】[0002]
【従来の技術】リチウム２次電池は、その高い容積効率
および重量効率が活かされて、例えばノート型パソコ
ン、携帯電話または電気自動車などの電源装置として用
いられている。2. Description of the Related Art A lithium secondary battery is used as a power supply device for, for example, a notebook personal computer, a mobile phone, or an electric vehicle due to its high volumetric efficiency and weight efficiency.
【０００３】特にリチウムイオン２次電池は、その電池
パック自体の安全性を高めるために、充放電に関する制
御回路が組み込まれている。In particular, a lithium-ion secondary battery has a built-in charge / discharge control circuit for enhancing the safety of the battery pack itself.
【０００４】図８に、このような従来のリチウムイオン
２次電池パックの回路構成を示す。この例では、満充電
時の電圧が約４Ｖとなる電池セル１が３個直列に接続さ
れ、Ｖｏｕｔ−Ｇｎｄ端子間で１２Ｖの出力を取り出し
ている。Ｖｃｈｒ，Ｖｄｔｃ，Ｖｔｈの各端子は充電器
に接続され、リチウムイオン２次電池を充電する際に使
用される。Ｄ１は逆流防止ダイオード、Ｒ１は充電電流
制御用抵抗であり、この例では抵抗Ｒ１が充電電流制御
用抵抗回路を構成している。充電時には、ＶｃｈｒとＧ
ｎｄ端子間に充電電圧が印加され、Ｖｃｈｒ→ダイオー
ドＤ１→抵抗Ｒ１→電池セル→ＦＥＴ→Ｇｎｄの経路で
充電電流が流れる。FIG. 8 shows a circuit configuration of such a conventional lithium ion secondary battery pack. In this example, three battery cells 1 whose voltage at the time of full charge is about 4 V are connected in series, and an output of 12 V is taken out between the Vout-Gnd terminals. Each terminal of Vchr, Vdtc, and Vth is connected to a charger and used when charging a lithium ion secondary battery. D1 is a backflow prevention diode, and R1 is a charging current control resistor. In this example, the resistor R1 forms a charging current control resistor circuit. When charging, Vchr and G
A charging voltage is applied between the nd terminals, and a charging current flows through a path of Vchr → diode D1 → resistance R1 → battery cell → FET → Gnd.
【０００５】図８において、過電圧・過電流・過放電検
出制御回路２は、電池セル１に対する過電圧・過電流・
過放電を検出した時、ＦＥＴをオフして電池セルに対す
る充放電電流を遮断する。Ｒntc は電池セル１の温度を
検出する温度センサとしての負特性サーミスタである。In FIG. 8, an overvoltage / overcurrent / overdischarge detection control circuit 2 controls an overvoltage / overcurrent / overcurrent
When overdischarge is detected, the FET is turned off to interrupt the charge / discharge current for the battery cell. Rntc is a negative characteristic thermistor as a temperature sensor for detecting the temperature of the battery cell 1.
【０００６】[0006]
【発明が解決しようとする課題】図８に示した従来のリ
チウムイオン２次電池パックにおいて、充電電流制御用
の抵抗Ｒ１は、例えば５０Ω（以下抵抗Ｒ１の抵抗値を
Ｒ１で表す。）に設定されている。通常の（平均的な）
充電時（以下、「通常充電時」という。）の電池セル電
圧Ｖｃは１１Ｖ程度であり、この時の充電電流は、 Ｉ＝（Ｖｃｈｒ−Ｖｃ）／Ｒ１＝（１２−１１）／５０
＝２０ｍＡ となる。In the conventional lithium ion secondary battery pack shown in FIG. 8, the resistance R1 for controlling the charging current is set to, for example, 50Ω (hereinafter, the resistance value of the resistance R1 is represented by R1). Have been. Normal (average)
The battery cell voltage Vc during charging (hereinafter, referred to as “normal charging”) is about 11 V, and the charging current at this time is I = (Vchr−Vc) / R1 = (12−11) / 50
= 20 mA.
【０００７】もし、電池セル１が放電されきっていて、
その蓄積電荷が略０であるときに、充電電圧Ｖｃｈｒ
（略１２Ｖ）が供給された場合、（以下、この状態を
「大電流充電時」という。）逆流防止ダイオードＤ１の
電圧降下および充電電流経路途中の各部の電圧降下を０
とすれば、両者の電位差（Ｖｃｈｒ−Ｖｃ＝１２Ｖ）が
抵抗Ｒ１の両端に印加され、抵抗Ｒ１には２４０ｍＡの
電流が流れる。この電流により抵抗Ｒ１は、 Ｐ＝Ｉ2 Ｒ１＝２．８８Ｗ の電力を消費する。このような大電力に耐え得る抵抗器
は相対的に極めて大型である。If the battery cell 1 has been completely discharged,
When the accumulated charge is substantially zero, the charging voltage Vchr
When (approximately 12 V) is supplied (hereinafter, this state is referred to as “during large current charging”), the voltage drop of the backflow prevention diode D1 and the voltage drop of each part in the charging current path are reduced to 0.
Then, the potential difference between them (Vchr-Vc = 12 V) is applied to both ends of the resistor R1, and a current of 240 mA flows through the resistor R1. With this current, the resistor R1 consumes power of P = I 2 R1 = 2.88W. Resistors that can withstand such high power are relatively extremely large.
【０００８】図９は従来のリチウムイオン２次電池パッ
クの内部に設けられる回路基板の構成を示す図である。
この回路基板は低コスト化および電池パック内での取り
付け性を考慮して通常片面実装基板が使用される。図９
に示すように、上記の大電力に耐え得る抵抗回路をチッ
プ抵抗器で構成する場合、３２１６型（縦３．２×横
１．６ｍｍ角）のチップ抵抗器を４個程度並列接続する
ことになる。FIG. 9 is a diagram showing a configuration of a circuit board provided inside a conventional lithium ion secondary battery pack.
As this circuit board, a single-sided mounting board is usually used in consideration of cost reduction and mountability in a battery pack. FIG.
As shown in the figure, when a resistor circuit capable of withstanding the above-mentioned high power is constituted by a chip resistor, about 4 chip resistors of type 3216 (3.2 × 1.6 mm square) are connected in parallel. Become.
【０００９】これらのチップ抵抗器の回路基板上に占め
る占有面積は非常に大きなものであり、このことが小型
化、低コスト化の妨げとなっていた。また、上記２４０
ｍＡという大きな充電電流が流れることは、充電器内の
シリーズレギュレーション用のトランジスタや整流ダイ
オードの電流定格を決定する上でも大きな影響を与え
る。すなわち上記トランジスタやダイオードとして、上
記大電流に耐えるだけの大容量の部品を使用する必要が
生じ、このことが充電器側でも小型化および低コスト化
の妨げとなっていた。The area occupied by these chip resistors on the circuit board is very large, which has hindered miniaturization and cost reduction. In addition, the above 240
The flow of a large charging current of mA has a great effect on determining the current rating of a series-regulating transistor and a rectifier diode in a charger. That is, it is necessary to use a large-capacity component capable of withstanding the large current as the transistor and the diode, which has hindered miniaturization and cost reduction on the charger side.
【００１０】尚、上記充電電流制御用抵抗Ｒ１の抵抗値
を予め高く設定すれば、最大充電電流を抑えることがで
きるが、それに伴い通常充電時の充電電流も小さくな
り、充電に長時間を要することになる。したがって、充
電電流制御用抵抗の抵抗値を必要以上に大きくすること
もできない。If the resistance value of the charging current control resistor R1 is set to a high value in advance, the maximum charging current can be suppressed. However, the charging current during normal charging also decreases, and a long time is required for charging. Will be. Therefore, the resistance value of the charging current control resistor cannot be increased more than necessary.
【００１１】この発明の目的は、上記問題を解消して、
大電流充電時の充電電流を抑え、且つ通常充電時の電池
セルへの適度な充電電流を確保し得るようにした２次電
池充電回路と、それを用いた充電器および電気機器を提
供することにある。An object of the present invention is to solve the above problems,
To provide a secondary battery charging circuit capable of suppressing a charging current at the time of large current charging and securing an appropriate charging current to a battery cell at the time of normal charging, and a charger and an electric device using the same. It is in.
【００１２】[0012]
【課題を解決するための手段】この発明は、大電流充電
時の充電電流を抑え、且つ通常充電時の電池セルへの適
度な充電電流を確保するため、リチウムイオン２次電池
の充電電流経路の逆流防止ダイオードに直列に接続され
る充電電流制御用抵抗回路に正特性サーミスタを設ける
ことを特徴とする。このことにより、蓄積電荷が０に近
い電池セルへの充電時に大きな充電電流が流れた場合
に、正特性サーミスタの自己発熱により抵抗値が上昇
し、その結果、過大な充電電流が抑制される。SUMMARY OF THE INVENTION The present invention provides a charging current path for a lithium ion secondary battery in order to suppress the charging current at the time of large current charging and to secure an appropriate charging current to the battery cell at the time of normal charging. Wherein a positive-characteristic thermistor is provided in the charging current control resistor circuit connected in series to the backflow prevention diode. As a result, when a large charge current flows when charging a battery cell having a stored charge close to 0, the self-heating of the positive temperature coefficient thermistor increases the resistance value, and as a result, an excessive charge current is suppressed.
【００１３】また、この発明は前記正特性サーミスタの
キュリー点における抵抗値（Ｒｃｐ）とトリップ（キュ
リー点を超えて高抵抗になった状態）後の安定抵抗値
（Ｒｔｎ）の比（Ｒｔｎ／Ｒｃｐ）を１００〜１０００
の範囲内とする。また、この発明は前記充電電流制御用
抵抗回路を、前記正特性サーミスタと固定抵抗器との並
列回路とする。これにより正特性サーミスタと固定抵抗
器の合成による抵抗温度特性を定める。これらにより、
大電流充電時の充電電流の上限と通常充電時の充電電流
値との関係をより最適に定めることができる。The present invention also relates to a ratio (Rtn / Rcp) of the resistance value (Rcp) at the Curie point of the positive temperature coefficient thermistor to the stable resistance value (Rtn) after a trip (high resistance beyond the Curie point). ) From 100 to 1000
Within the range. Further, according to the present invention, the charging current control resistor circuit is a parallel circuit of the PTC thermistor and a fixed resistor. This determines the resistance-temperature characteristic by combining the positive characteristic thermistor and the fixed resistor. By these,
The relationship between the upper limit of the charging current during large-current charging and the charging current value during normal charging can be determined more optimally.
【００１４】[0014]
【発明の実施の形態】まずリチウムイオン２次電池パッ
ク（以下電池パックという）に対する充電器の回路構成
を図１に示す。図１において整流回路３はＡＣ１００Ｖ
入力をピーク電圧約１４０Ｖの略直流電圧に整流平滑す
る。ＤＣ−ＤＣコンバータ４はスイッチングレギュレー
タであり、入力されたＤＣ電源電圧をＤＣ１２Ｖに降圧
する。トランジスタＴｒはシリーズレギュレータ回路を
構成し、充電制御回路５はＤＣ−ＤＣコンバータ４から
出力される電圧を電源電圧として動作し、電池パックの
Ｖｄｔｃ端子からの電圧検出信号に応じて、また電池パ
ックのＶｔｈ端子からの温度検出信号に応じて、トラン
ジスタＴｒのベース電流を制御することにより、電池パ
ックに対する充電電流を制御する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a circuit configuration of a charger for a lithium ion secondary battery pack (hereinafter referred to as a battery pack). In FIG. 1, the rectifier circuit 3 is 100 V AC.
The input is rectified and smoothed to a substantially DC voltage having a peak voltage of about 140V. The DC-DC converter 4 is a switching regulator, and reduces the input DC power supply voltage to DC12V. The transistor Tr forms a series regulator circuit, the charging control circuit 5 operates using the voltage output from the DC-DC converter 4 as a power supply voltage, and responds to a voltage detection signal from the Vdtc terminal of the battery pack, By controlling the base current of the transistor Tr according to the temperature detection signal from the Vth terminal, the charging current to the battery pack is controlled.
【００１５】図２は電池パックの回路構成を示す図であ
る。図８に示した従来の回路と異なり、充電電流制御用
抵抗回路の抵抗として正特性サーミスタＲptc を用いて
いる。FIG. 2 is a diagram showing a circuit configuration of the battery pack. Unlike the conventional circuit shown in FIG. 8, a positive-characteristic thermistor Rptc is used as the resistance of the charging current control resistance circuit.
【００１６】なお、Ｖｄｔｃ端子に接続される抵抗Ｒ２
は、電圧検出保護用抵抗である。このＶｄｔｃ端子に接
続される電圧検出回路側のモードによって大電流が流れ
る場合には、固定抵抗に代えて正特性サーミスタを用い
ることもできる。A resistor R2 connected to the Vdtc terminal
Is a voltage detection protection resistor. When a large current flows depending on the mode of the voltage detection circuit connected to the Vdtc terminal, a positive temperature coefficient thermistor can be used instead of the fixed resistor.
【００１７】図３は上記Ｒptc の抵抗−温度特性であ
る。この例では、キュリー点ＣＰ（抵抗値が２５℃にお
ける抵抗値の２倍となるときの温度）が１００℃であ
り、常温２５℃で５０Ωを示し、通常の使用温度環境０
℃〜６０℃で５０±１０Ωを示す。また、トリップ後の
安定抵抗値は５０ｋΩを示す。ここでキュリー点におけ
る抵抗値をＲｃｐ、トリップ後の安定抵抗値をＲｔｎと
すれば、Ｒｔｎ／Ｒｃｐ比は１０００となる。FIG. 3 shows the resistance-temperature characteristics of Rptc. In this example, the Curie point CP (the temperature at which the resistance value becomes twice the resistance value at 25 ° C.) is 100 ° C., which indicates 50Ω at normal temperature 25 ° C.
It shows 50 ± 10Ω between 60 ° C and 60 ° C. Further, the stable resistance value after the trip indicates 50 kΩ. If the resistance value at the Curie point is Rcp and the stable resistance value after the trip is Rtn, the Rtn / Rcp ratio is 1000.
【００１８】上記抵抗温度特性の正特性サーミスタＲpt
c を用いて、図２に示したように回路を構成することに
より、通常充電時には使用温度環境に応じて５０±１０
Ωのチップ抵抗器として作用し、電池セルの蓄積電荷が
略０であるときの充電に際しては、正特性サーミスタＲ
ptc の抵抗値が自己発熱によりキュリー点ＣＰを超え、
例えば５０ｋΩの高抵抗となる。The positive temperature coefficient thermistor Rpt of the temperature resistance characteristic
By using c to configure the circuit as shown in FIG. 2, during normal charging, 50 ± 10
Acting as a chip resistor of Ω, the positive-characteristic thermistor R
The resistance value of ptc exceeds the Curie point CP due to self-heating,
For example, the resistance becomes high at 50 kΩ.
【００１９】ここで、先ず、通常の状態の電池セルへの
充電電流を検討すると、電池セル電圧Ｖｃが１１Ｖの
時、正特性サーミスタＲptc に流れる充電電流は、 Ｉ＝（Ｖｃｈｒ−Ｖｃ）／Ｒ１＝（１２−１１）／５０
＝２０ｍＡ となる。First, when the charging current to the battery cell in the normal state is examined, when the battery cell voltage Vc is 11 V, the charging current flowing through the positive characteristic thermistor Rptc is I = (Vchr-Vc) / R1 = (12-11) / 50
= 20 mA.
【００２０】この時の正特性サーミスタＲptc で消費さ
れる電力（自己発熱電力）は、 （自己発熱電力）＝Ｉ2 Ｒ＝０．０２2 ×５０＝０．０
２Ｗ であり、自己発熱による温度上昇は、 （自己発熱による温度上昇）＝自己発熱電力／熱放散定
数＝０．０２／０．００１＝２０℃ となり、正特性サーミスタＲptc の温度は使用環境温度
に対し＋２０℃程度となる。このときの使用環境温度が
６０℃と高い場合でも、正特性サーミスタＲptcの温度
は８０℃になるだけであって、図３から明らかなよう
に、抵抗値は依然として安定抵抗値（５０±１０Ω）の
領域である。The power consumed by the PTC thermistor Rptc when the (self-heating power), (self-heating power) = I 2 R = 0.02 2 × 50 = 0.0
The temperature rise due to self-heating is as follows: (Temperature rise due to self-heating) = self-heating power / heat dissipation constant = 0.02 / 0.001 = 20 ° C. The temperature of the positive characteristic thermistor Rptc is equal to the operating temperature. On the other hand, it is about + 20 ° C. Even if the use environment temperature at this time is as high as 60 ° C., the temperature of the positive temperature coefficient thermistor Rptc is only 80 ° C., and as is clear from FIG. 3, the resistance value is still a stable resistance value (50 ± 10Ω). Area.
【００２１】次に、放電されきった状態の電池セルへの
充電電流を検討すると、このとき電池セル電圧Ｖｃは略
０Ｖであり、 Ｉ＝（Ｖｃｈｒ−Ｖｃ）／Ｒ１＝（１２−０）／５０＝
２４０ｍＡ となる。この時の正特性サーミスタＲptc の自己発熱を
計算すると、 （自己発熱電力）＝Ｉ2 Ｒ＝０．２４2 ×５０＝２．２
８Ｗ であり、自己発熱による温度上昇は、 （自己発熱による温度上昇）＝自己発熱電力／熱放散定
数＝２．２８／０．００１＝２８８０℃ となり、極めて急峻な自己発熱によりキュリー点＝１０
０℃を超えることがわかる。Next, when examining the charging current to the battery cell in a completely discharged state, the battery cell voltage Vc at this time is approximately 0 V, and I = (Vchr-Vc) / R1 = (12-0) / 50 =
240 mA. Calculating the self-heating of the PTC thermistor Rptc at this time (self-heating power) = I 2 R = 0.24 2 × 50 = 2.2
The temperature rise due to self-heating is as follows: (temperature rise due to self-heating) = self-heating power / heat dissipation constant = 2.28 / 0.001 = 2880 ° C., and the Curie point = 10 due to extremely steep self-heating.
It turns out that it exceeds 0 degreeC.
【００２２】ここで、正特性サーミスタＲptc の自己発
熱による温度上昇が１００℃となる電池セル電圧Ｖｃを
求めると、 自己発熱電力／熱放散定数＝Ｑ／０．００１＝１００℃ の関係より、Ｑ＝０．１Ｗ 自己発熱電力＝Ｉ2 Ｒ＝Ｉ2 ×５０＝０．１Ｗ の関係より、Ｉ＝０．０４５Ａとして求まる。したがっ
て、 １２−Ｖｃ＝Ｉ・Ｒ１＝０．０４５×５０＝２．２５Ｖ の関係より、Ｖｃ＝９．７５Ｖとなる。Here, when the battery cell voltage Vc at which the temperature rise due to self-heating of the positive temperature coefficient thermistor Rptc becomes 100 ° C. is obtained, from the relationship of self-heating power / heat dissipation constant = Q / 0.001 = 100 ° C. = 0.1 W Self-heating power = I 2 R = I 2 × 50 = 0.1 W From the relationship, I = 0.045 A is obtained. Therefore, Vc = 9.75V from the relationship of 12−Vc = I · R1 = 0.045 × 50 = 2.25V.
【００２３】このように、電池セルの放電が進み、Ｖｃ
＜９．７５Ｖとなった電池セルに対しては、過大な充電
電流が約１／１０００のレベルに抑制される。また、こ
の電池セルに対する充電を開始した後、正特性サーミス
タＲptc の温度が低下するにしたがって抵抗値が小さく
なることにより、充電電流が増大していく。しかし、充
電電流の増大→温度上昇→抵抗値増大→充電電流の減少
という自己負帰還作用により、適度な充電電流による充
電が進行する。そして充電が進んでＶｃ＞９．７５Ｖと
なった時、正特性サーミスタの抵抗値は５０Ω程度にま
で復帰し、通常の充電電流による充電に移行する。As described above, the discharge of the battery cell proceeds, and Vc
For a battery cell of <9.75 V, the excessive charging current is suppressed to a level of about 1/1000. After the charging of the battery cell is started, the resistance value decreases as the temperature of the positive temperature coefficient thermistor Rptc decreases, so that the charging current increases. However, due to the self-negative feedback action of increasing the charging current → increasing the temperature → increasing the resistance value → decreasing the charging current, charging with an appropriate charging current proceeds. When the charging proceeds and Vc> 9.75V, the resistance value of the positive temperature coefficient thermistor returns to about 50Ω, and the charging shifts to the normal charging current.
【００２４】図４は電池パックに内蔵される回路基板の
構成を示す図である。図９に示した従来の電池パックに
おける回路基板と比較すれば明らかなように、充電電流
制御用の抵抗として正特性サーミスタＲptc を用いたこ
とにより、従来は大型のチップ抵抗が多数必要であった
のに比べて、本願発明によれば、小型のチップ状正特性
サーミスタ素子を１個だけ用いればよい。その結果、回
路基板上の占有面積を縮小化でき、回路基板全体が小型
化される。図中二点鎖線は図９に示した従来の回路基板
の大きさを示している。FIG. 4 is a diagram showing a configuration of a circuit board incorporated in the battery pack. As is apparent from comparison with the circuit board of the conventional battery pack shown in FIG. 9, the use of a positive temperature coefficient thermistor Rptc as a resistor for controlling the charging current required a large number of large chip resistors in the past. In contrast, according to the present invention, only one small chip-shaped positive temperature coefficient thermistor element needs to be used. As a result, the occupied area on the circuit board can be reduced, and the entire circuit board can be downsized. The two-dot chain line in the figure indicates the size of the conventional circuit board shown in FIG.
【００２５】ここで正特性サーミスタＲptc は１６０８
型（縦１．６×横０．８ｍｍ角）のチップ状正特性サー
ミスタであり、熱放散係数１．０ｍＷ／℃（静止空気
中）のものを用いる。これにより充電電流制御用抵抗部
分の実装スペースを約１／２０にまで省スペース化を図
ることができ、逆流防止ダイオードＤ１としても低容量
のダイオードを使用できるため、基板形状全体でも２０
〜３０％の小型化を図ることができる。Here, the positive characteristic thermistor Rptc is 1608
This is a type (1.6 × 0.8 mm square) chip-type positive temperature coefficient thermistor having a heat dissipation coefficient of 1.0 mW / ° C. (in still air). As a result, the mounting space for the charging current control resistor can be reduced to about 1/20, and a low-capacity diode can be used as the backflow prevention diode D1.
A size reduction of up to 30% can be achieved.
【００２６】以上に示した例では、充電電流制御用の正
特性サーミスタのＲｔｎ／Ｒｃｐ比を１０００とした
が、この比が１０００を超えると、充電電流抑制時の充
電電流が非常に小さな値となって、電池セルの電圧Ｖｃ
が上記の例では９．７５Ｖを超えるまでに長時間を要す
ることになる。そこで上記抵抗変化率（Ｒｔｎ／Ｒｃ
ｐ）としては、意図的に１０００より低くした正特性サ
ーミスタを用いる。ただし、抵抗変化率が小さすぎると
充電電流抑制効果が小さくなって目的が達せられない。In the example described above, the Rtn / Rcp ratio of the positive-characteristic thermistor for controlling the charging current is set to 1000. However, if this ratio exceeds 1000, the charging current when suppressing the charging current becomes a very small value. And the voltage Vc of the battery cell
However, in the above example, it takes a long time to exceed 9.75V. Then, the resistance change rate (Rtn / Rc)
As p), a positive temperature coefficient thermistor intentionally lower than 1000 is used. However, if the rate of change in resistance is too small, the effect of suppressing the charging current becomes small, and the object cannot be achieved.
【００２７】ここで、抵抗変化が５０Ω〜５ｋΩの範囲
で変化する（Ｒｔｎ／Ｒｃｐ比が１００の）正特性サー
ミスタを用いた場合について考察する。まず大電流充電
時に流れる充電電流は、上記のとおり、２４０ｍＡとな
り、そのときの、自己発熱による温度上昇は、急峻に１
００℃を超え、正特性サーミスタＲptc の抵抗値は５ｋ
Ωとなって、充電電流は、 Ｉ＝（Ｖｃｈｒ−Ｖｃ）／Ｒ1 ＝（１２−０）／５ｋ＝
２．４ｍＡ となる。この時の正特性サーミスタＲptc の自己発熱を
計算すると、 （自己発熱電力）＝Ｉ2 Ｒ＝０．００２４2 ×５ｋ＝
０．０２８８Ｗ であり、自己発熱による温度上昇は、 （自己発熱による温度上昇）＝自己発熱電力／熱放散定
数＝０．０２８８／０．００１＝２９℃ となり、このときの正特性サーミスタの温度がキュリー
点の温度１００℃＋２９℃＝１２９℃となる。もし、こ
れ以上の温度に達すると、回路基板が焦げる等の不具合
が発生する。したがって、上記抵抗変化率の値は１００
程度が限度である。Here, consider the case where a positive temperature coefficient thermistor (Rtn / Rcp ratio is 100) that changes in resistance in the range of 50 Ω to 5 kΩ is used. First, the charging current flowing during large-current charging is 240 mA, as described above, and the temperature rise due to self-heating at this time steeply increases by 1%.
Exceeds 00 ° C and the resistance of the positive temperature coefficient thermistor Rptc is 5k
Ω, and the charging current becomes: I = (Vchr−Vc) / R1 = (12-0) / 5k =
2.4 mA. When the self-heating of the positive characteristic thermistor Rptc at this time is calculated, (self-heating power) = I 2 R = 0.0024 2 × 5k =
0.0288W, and the temperature rise due to self-heating is as follows: (temperature rise due to self-heating) = self-heating power / heat dissipation constant = 0.0288 / 0.001 = 29 ° C. The Curie point temperature is 100 ° C. + 29 ° C. = 129 ° C. If the temperature reaches a temperature higher than this, problems such as burning of the circuit board occur. Therefore, the value of the resistance change rate is 100
The degree is the limit.
【００２８】なお、抵抗変化率を低く抑えた正特性サー
ミスタの製造方法としては、主成分となるＢａＴｉＯ
3 に対しＢａと置換するＰｂやストロンチウムの含有量
を抑制した正特性サーミスタ材料を使用する。仮焼・
混合・成形後のＢａＴｉＯ3を主成分とするセラミック
正特性サーミスタ材料の焼成を還元性雰囲気中で行う方
法などが有効である。As a method of manufacturing a positive temperature coefficient thermistor with a low rate of change in resistance, BaTiO as a main component is used.
A positive temperature coefficient thermistor material in which the content of Pb or strontium which replaces Ba with respect to 3 is suppressed is used. Calcined
It is effective to bake the ceramic positive temperature coefficient thermistor material mainly composed of BaTiO 3 after mixing and molding in a reducing atmosphere.
【００２９】次に、充電電流制御用抵抗回路の異なっ
た、他の実施形態のリチウムイオン２次電池充電回路の
構成を図６および図７を参照して説明する。図６は電池
パックの回路構成を示す図である。図２に示した回路と
異なり、充電電流制御用抵抗回路を、正特性サーミスタ
Ｒptc と固定抵抗器Ｒ３との並列回路で構成している。Next, the configuration of a lithium ion secondary battery charging circuit according to another embodiment, which is different from the charging current control resistance circuit, will be described with reference to FIGS. 6 and 7. FIG. FIG. 6 is a diagram showing a circuit configuration of the battery pack. Unlike the circuit shown in FIG. 2, the charging current control resistor circuit is configured by a parallel circuit of a positive characteristic thermistor Rptc and a fixed resistor R3.
【００３０】図７は図６に示した正特性サーミスタＲpt
c の抵抗温度特性が図３に示したものに等しく、固定抵
抗器Ｒ３が５０ｋΩである場合の抵抗温度特性を示す図
である。ここで実線が合成抵抗温度特性、破線が正特性
サーミスタＲptc 単体での抵抗温度特性である。FIG. 7 shows the positive temperature coefficient thermistor Rpt shown in FIG.
FIG. 4 is a diagram showing resistance-temperature characteristics when the resistance-temperature characteristic of c is equal to that shown in FIG. 3 and the fixed resistor R3 is 50 kΩ. Here, the solid line is the combined resistance temperature characteristic, and the broken line is the resistance temperature characteristic of the positive characteristic thermistor Rptc alone.
【００３１】この回路により、通常充電時の電流Ｉは、 Ｉ＝（１２−１１）／５０＝２０ｍＡ となり、効率よく充電される。With this circuit, the current I during normal charging is I = (12−11) / 50 = 20 mA, and charging is efficient.
【００３２】大電流充電時の電流Ｉは、 Ｉ＝１２／２５ｋΩ＝０．４８ｍＡ となり、充電開始直後の充電電流が適度に抑制される。The current I during large-current charging is I = 12/25 kΩ = 0.48 mA, and the charging current immediately after the start of charging is appropriately suppressed.
【００３３】なお、以上に示した実施形態では、チップ
部品としての正特性サーミスタを回路基板上に表面実装
する例を示したが、リード端子付きの正特性サーミスタ
を用いてもよい。In the above-described embodiment, an example is shown in which a PTC thermistor as a chip component is surface-mounted on a circuit board, but a PTC thermistor with lead terminals may be used.
【００３４】また、主にノート型パソコンに使用される
ＤＣ１２Ｖ系のリチウムイオン２次電池の充電回路につ
いて示したが、本発明は、携帯電話機や電気自動車など
のリチウムイオン電池セルを用いた他の電圧系の電池に
対しても適用できる。Although the charging circuit of a DC12V lithium-ion secondary battery mainly used in a notebook personal computer has been described, the present invention relates to another battery using a lithium-ion battery cell such as a mobile phone or an electric vehicle. It can also be applied to voltage type batteries.
【００３５】また、図１、図２、図４、図６等に示した
例では、リチウムイオン２次電池パックに２次電池充電
回路を内蔵させた例を示したが、本発明は充電器自体に
も適用できるものである。すなわち、上記各図に示した
２次電池充電回路を充電器側に設けてもよい。さらに、
同様にして本発明は、２次電池充電回路が組み込まれた
電気機器にも適用可能である。Also, in the examples shown in FIGS. 1, 2, 4, 6 and the like, examples are shown in which a rechargeable battery charging circuit is built in a lithium ion rechargeable battery pack. It can be applied to itself. That is, the secondary battery charging circuit shown in each of the above drawings may be provided on the charger side. further,
Similarly, the present invention is also applicable to electric equipment in which a secondary battery charging circuit is incorporated.
【００３６】また、本発明の好ましい用途は、リチウム
イオン２次電池およびリチウムポリマー２次電池である
が、本発明は他の２次電池に対しても同様に適用でき
る。The preferred uses of the present invention are a lithium ion secondary battery and a lithium polymer secondary battery, but the present invention can be similarly applied to other secondary batteries.
【００３７】[0037]
【発明の効果】請求項１、４、５に記載の発明によれ
ば、蓄積電荷が０に近い電池セルへの充電時に大きな充
電電流が流れた場合（大電流充電時）に、正特性サーミ
スタの自己発熱により抵抗値が上昇し、その結果、過大
な充電電流が抑制される。According to the first, fourth and fifth aspects of the present invention, when a large charging current flows during charging of a battery cell having a stored charge close to 0 (during large current charging), a positive temperature coefficient thermistor is obtained. The self-heating causes the resistance value to increase, and as a result, excessive charging current is suppressed.
【００３８】特に請求項２に記載の発明によれば、通常
充電時の電流を確保するとともに、大電流充電時の電流
を適度に抑制することができる。In particular, according to the second aspect of the present invention, the current during normal charging can be ensured, and the current during large-current charging can be appropriately suppressed.
【００３９】また、請求項３に記載の発明によれば、正
特性サーミスタの特性と固定抵抗器の抵抗値を適宜設定
することによって、大電流充電時の充電電流の上限と通
常充電時の充電電流値との関係をより容易に定めること
ができる。According to the third aspect of the present invention, by appropriately setting the characteristics of the positive temperature coefficient thermistor and the resistance value of the fixed resistor, the upper limit of the charging current at the time of large current charging and the charging at the time of normal charging are set. The relationship with the current value can be more easily determined.
【図１】実施形態で用いるリチウムイオン２次電池の充
電器の回路構成を示す図FIG. 1 is a diagram showing a circuit configuration of a charger for a lithium ion secondary battery used in an embodiment.
【図２】第１の実施形態に係るリチウムイオン２次電池
の電池パックの構成を示す図FIG. 2 is a diagram showing a configuration of a battery pack of the lithium ion secondary battery according to the first embodiment.
【図３】同電池パックに内蔵される充電電流制御用の正
特性サーミスタの抵抗温度特性を示す図FIG. 3 is a diagram showing a resistance temperature characteristic of a positive-characteristic thermistor for charging current control built in the battery pack.
【図４】電池パックに内蔵される回路基板の構成を示す
図FIG. 4 is a diagram showing a configuration of a circuit board incorporated in the battery pack.
【図５】正特性サーミスタの他の抵抗温度特性を示す図FIG. 5 is a diagram showing another resistance temperature characteristic of the positive temperature coefficient thermistor;
【図６】第２の実施形態に係るリチウムイオン２次電池
の電池パックの構成を示す図FIG. 6 is a diagram showing a configuration of a battery pack of a lithium ion secondary battery according to a second embodiment.
【図７】同回路における充電電流制御用抵抗回路の抵抗
温度特性を示す図FIG. 7 is a diagram showing a resistance temperature characteristic of a charging current control resistance circuit in the same circuit.
【図８】従来のリチウムイオン２次電池の電池パックの
構成を示す図FIG. 8 is a diagram showing a configuration of a battery pack of a conventional lithium ion secondary battery.
【図９】同電池パックに内蔵される回路基板の構成を示
す図FIG. 9 is a diagram showing a configuration of a circuit board built in the battery pack.
１−電池セル Ｒptc −正特性サーミスタ Ｒ１−充電電流制御用抵抗 1-Battery cell Rptc-Positive thermistor R1-Charge current control resistor
フロントページの続き (72)発明者 高岡 祐一 京都府長岡京市天神二丁目26番10号 株式 会社村田製作所内 Ｆターム(参考） 5G003 AA01 BA01 CC01 FA04 FA08 GA01 GB03 5G013 AA09 BA01 CA02 Continued on the front page (72) Inventor Yuichi Takaoka 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto F-term in Murata Manufacturing Co., Ltd. (Reference) 5G003 AA01 BA01 CC01 FA04 FA08 GA01 GB03 5G013 AA09 BA01 CA02
Claims (5)
オードに直列に接続される充電電流制御用抵抗回路に正
特性サーミスタを設けたことを特徴とする２次電池充電
回路。1. A rechargeable battery charging circuit, comprising a positive current thermistor provided in a charging current control resistor circuit connected in series to a backflow prevention diode in a charging current path of a rechargeable battery.
ける抵抗値（Ｒｃｐ）とトリップ後の安定抵抗値（Ｒｔ
ｎ）の比（Ｒｔｎ／Ｒｃｐ）を１００〜１０００の範囲
内とした請求項１に記載の２次電池充電回路。2. The resistance (Rcp) at the Curie point of the positive temperature coefficient thermistor and the stable resistance (Rt) after a trip.
2. The secondary battery charging circuit according to claim 1, wherein the ratio (Rtn / Rcp) of n) is in a range of 100 to 1000. 3.
特性サーミスタと固定抵抗器との並列回路とした請求項
１に記載の２次電池充電回路。3. The secondary battery charging circuit according to claim 1, wherein the charging current control resistance circuit is a parallel circuit of the positive temperature coefficient thermistor and a fixed resistor.
充電回路を備えて成る充電器。4. A charger comprising the secondary battery charging circuit according to claim 1.
充電回路を備えて成る電気機器。5. An electric device comprising the secondary battery charging circuit according to claim 1, 2 or 3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11083133A JP2000278869A (en) | 1999-03-26 | 1999-03-26 | Secondary battery charging circuit, charger, and electric apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11083133A JP2000278869A (en) | 1999-03-26 | 1999-03-26 | Secondary battery charging circuit, charger, and electric apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2000278869A true JP2000278869A (en) | 2000-10-06 |
Family
ID=13793713
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11083133A Pending JP2000278869A (en) | 1999-03-26 | 1999-03-26 | Secondary battery charging circuit, charger, and electric apparatus |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2000278869A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPWO2005025029A1 (en) * | 2003-09-03 | 2006-11-16 | 松下電器産業株式会社 | Power storage device and wiring pattern |
| US7737658B2 (en) | 2003-10-27 | 2010-06-15 | Sony Corporation | Battery packs having a charging mode and a discharging mode |
| CN104052135A (en) * | 2013-03-11 | 2014-09-17 | 宏达国际电子股份有限公司 | Mobile electronic system and charging accessory |
| EP2858202A4 (en) * | 2012-05-25 | 2015-09-30 | Panasonic Ip Man Co Ltd | In-vehicle power supply device and photovoltaic power generation device |
| CN110797942A (en) * | 2019-11-05 | 2020-02-14 | 中国船舶重工集团公司第七0五研究所 | Trickle charge circuit based on super capacitor |
| JP2020519225A (en) * | 2017-05-08 | 2020-06-25 | ブラウン ゲーエムベーハー | Electric circuit and method for charging a secondary battery |
-
1999
- 1999-03-26 JP JP11083133A patent/JP2000278869A/en active Pending
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPWO2005025029A1 (en) * | 2003-09-03 | 2006-11-16 | 松下電器産業株式会社 | Power storage device and wiring pattern |
| JP4732897B2 (en) * | 2003-09-03 | 2011-07-27 | パナソニック株式会社 | Power storage device and wiring pattern |
| US7737658B2 (en) | 2003-10-27 | 2010-06-15 | Sony Corporation | Battery packs having a charging mode and a discharging mode |
| EP2858202A4 (en) * | 2012-05-25 | 2015-09-30 | Panasonic Ip Man Co Ltd | In-vehicle power supply device and photovoltaic power generation device |
| US9834102B2 (en) | 2012-05-25 | 2017-12-05 | Panasonic Intellectual Property Management Co., Ltd. | In-vehicle power supply device |
| CN104052135A (en) * | 2013-03-11 | 2014-09-17 | 宏达国际电子股份有限公司 | Mobile electronic system and charging accessory |
| US9478999B2 (en) | 2013-03-11 | 2016-10-25 | Htc Corporation | Mobile electronic system and charging accessory |
| JP2020519225A (en) * | 2017-05-08 | 2020-06-25 | ブラウン ゲーエムベーハー | Electric circuit and method for charging a secondary battery |
| CN110797942A (en) * | 2019-11-05 | 2020-02-14 | 中国船舶重工集团公司第七0五研究所 | Trickle charge circuit based on super capacitor |
| CN110797942B (en) * | 2019-11-05 | 2023-06-02 | 中国船舶重工集团公司第七0五研究所 | Trickle charging circuit based on super capacitor |
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