JPS631820B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a battery charging device that includes temperature detection means for detecting a predetermined temperature rise of a battery to be charged and voltage detection means for detecting a predetermined charging voltage of the battery.

The charging voltage characteristics of a battery to be charged, such as a NiCd battery, are such that as the ambient temperature increases, the charging voltage decreases, as shown by characteristics .about. in FIG. Therefore, when detecting the battery voltage to detect the predetermined state of charge of the battery, when the ambient temperature is in a high temperature range, for example 40°C, it is clear from the characteristics that the battery voltage changes little and the battery voltage corresponding to the predetermined state of charge of the battery. is difficult to detect.

On the other hand, in a battery, a charging chemical reaction occurs within the battery due to the inflow of charging current, and the battery temperature rises. However, when the ambient temperature is low, the battery temperature does not rise much, making it difficult to detect the temperature rise. When the ambient temperature is in a high temperature range, the temperature rise of the battery is high, making it easy to detect the temperature rise.

Therefore, in the conventional device, a voltage detection means and a temperature detection means are used together, and the voltage detection means is mainly made to function in a low temperature region, and the temperature detection means is made to mainly function in a high temperature region.

However, the charging voltage characteristics and charging temperature characteristics of batteries differ due to variations in battery manufacturing even when the ambient temperature is the same. For this reason, in conventional devices, if the boundary between the low temperature region and high temperature region of the ambient temperature is, for example, 10°C, there is no guarantee that only the temperature detection means will function when this temperature exceeds 10°C.
Depending on the characteristics of the battery, the voltage detection means may function to finish charging the battery, but there is a risk of insufficient charging.

The present invention has been invented in view of this point, and one embodiment of the present invention will be described below with reference to FIG. 2. In this drawing, X is a charger, Y is a battery pack, and by connecting the output terminals O ₁ and O ₂ of the charger to the input terminals I ₁ and I ₂ of the battery pack,
Power is supplied to battery pack Y. Charger X has a step-down transformer T, whose primary coil _N1 is connected to the commercial power supply terminal.
P _e , P _e , and both ends of the secondary coil N ₂ are connected to the positive terminal P _p via diodes D ₁ , D ₂ .
The intermediate taps of N ₂ are connected to the negative terminals P _N respectively.
The positive terminal P _p is connected to the output terminal O ₁ through the positive line Lp,
The negative terminals P _N are respectively connected to the output terminals O ₂ via negative lines L _N , and a silicon controlled rectifier (hereinafter referred to as SCR) (S ₁ ) and a backflow blocking diode D ₃ are inserted in the positive line L _P. ing. The emitter and collector of the first transistor Q ₁ are interposed between the anode and gate of the SCR (S ₁ ). The base of the first transistor is connected to the negative terminal P _N through a series circuit of the collector-emitter of the second transistor Q ₂ and a diode D ₄ as a constant voltage element.
A series circuit of a diode D ₅ and a smoothing capacitor C ₁ is connected between the positive and negative terminals P _p and P _N , and resistors R ₁ and SCR are connected between both ends of the smoothing capacitor.
(S ₂ ) and the start switch SW are connected in parallel. Connection point of resistor R ₁ and SCR (S ₂ )
P ₁ is connected to the base of the second transistor Q ₂ .
The SCR (S ₂ ) is ignited by the output of voltage detection means VD for detecting a predetermined charging voltage of battery B of battery pack Y or by the output of temperature detection means TD for detecting a predetermined temperature rise of battery B.

The voltage detection means VD is configured as follows. That is, a resistive voltage divider circuit _RC1 is provided between the positive and negative lines _Lp and _LN , and the emitter of the third transistor _Q3 whose base is connected to this voltage dividing point _P2 is SCR ( _{S2 )} through the diode D6. The collector of the third transistor _Q3 is connected to the positive terminal of the smoothing capacitor _C1 . Between the partial pressure point P ₂ and the negative line L _N , there is a first thermostat H ₁ and an SCR (S ₃ ) that open when the ambient temperature is below the boundary temperature between the low temperature region and the high temperature region (for example, 10°C). A series circuit is inserted. The gate of the SCR is connected to a voltage dividing point P ₃ of a series circuit of a diode D ₇ and resistors R ₂ and R ₃ connected in parallel to a smoothing capacitor C ₁ . A capacitor C ₂ is connected in parallel to the resistor R ₂ .

The temperature detection means TD is a second thermostat H ₂ connected in series with the battery B in the battery pack Y, and when the thermostat is opened, the battery charging current is cut off by checking that there is no voltage drop across the backflow blocking diode D ₃ . A fourth transistor Q 4 is detected by Q ₄ and a fifth transistor Q 4 is shut off by shutting off the fourth transistor Q 4 .
The collector of the _fifth transistor is connected to the positive terminal of the smoothing capacitor _C1 , and the collector output of the fifth transistor is applied to the gate of the SCR ( _S2 ) via the diode _D8 . .

In the above configuration, the output terminals O ₁ of charger X,
Connect O ₂ to input terminals I ₁ and I ₂ of battery pack Y,
The operation when a commercial power source is connected between power terminals P _e and P _e will be explained.

The ambient temperature when charging starts now is the boundary temperature (for example,
10℃), the first thermostat
Since H ₁ is open and the negative voltage of capacitor C ₂ is applied to the gate of SCR (S ₃ ), even if the ambient temperature rises above the boundary temperature after charging starts, SCR (S ₃ )
does not conduct ignition.

In this state, battery B is charged via the second thermostat _H2 , and the battery voltage increases according to the charging voltage characteristic at ambient temperature (see FIG. 1). Since the ambient temperature is low, the battery temperature does not reach the point where the second thermostat _H2 is opened, and when the battery voltage reaches the predetermined charging voltage, the voltage at the voltage dividing point _P2 of the resistor voltage divider circuit _RC1 rises, and the second thermostat H2 opens. 3 transistor _Q3 becomes conductive. Therefore, the gate current flows into the SCR (S ₂ ) through the third transistor, and the ignition becomes conductive.
Since the base voltage of the second transistor _Q2 decreases, the second transistor turns off. Therefore, the first
Since transistor Q ₁ is cut off, SCR (S ₁ ) is cut off and charging of battery B is terminated. At the same time, the second transistor _Q2 is cut off, and the charging indicator L is turned off.
goes off to indicate charging completion status. In this state, the SCR (S ₂ ) is maintained conductive by the smoothed voltage of the smoothing capacitor C ₁ , so even if the battery voltage decreases after charging is completed, the fully charged state of battery B is maintained.

Next, assuming that the ambient temperature at the start of charging is higher than the boundary temperature, the _first thermostat _H1 is closed and the SCR ( A gate current flows into S ₃ ). Therefore, even if the battery voltage rises to the predetermined charging voltage after charging starts, the voltage at the voltage dividing point _P2 does not rise and the third transistor _Q3 does not become conductive. In this state, when the voltage is charged to a predetermined charging state, the battery temperature rises to a predetermined rising temperature, and the second thermostat _H2 is opened.
Therefore, the charging current of battery B is cut off, so there is no voltage drop across the reverse blocking diode _D3 .
The fourth transistor Q ₄ is turned off, and the fifth transistor Q ₅ is also turned off. Therefore, the collector voltage of the fifth transistor increases, igniting and conducting the SCR (S ₂ ) and cutting off the SCR (S ₁ ) as described above. This charging completion state is maintained by keeping the SCR (S ₂ ) conductive, as described above.

Next, FIG. 3 shows another embodiment of the present invention, and this embodiment will be described below. Charger X and battery pack Y each have three terminals O ₁ to O ₃ and I ₁ to I ₃ , and battery B is charged by connecting these terminals. The negative line _LN includes a relay switch RW that closes when the relay coil RY is excited, and an SCR (S ₄ ) that cuts off the charging current of the battery B after the relay switch or the second thermostat H ₂ is opened. is inserted. A series circuit of a diode D ₉ , a resistor R ₄ and a Zener diode Z is inserted between the output terminal O ₃ and the negative line L _N , and a capacitor C ₃ is connected in parallel between both ends of the Zener diode. A series circuit of a resistor R ₅ and a resistor R ₆ is connected, and the resistor voltage dividing point P ₄ is connected to the gate of the SCR (S ₄ ). Further, the voltage detection means VD is connected between the positive and negative lines L _p and L _N. That is,
The voltage detection means VD includes a resistor voltage divider circuit RC ₂ that detects the battery voltage, a sixth transistor Q ₆ that becomes conductive when the voltage at the voltage division point P ₅ of the circuit reaches a predetermined value,
A series circuit of a first thermostat _H1 and an SCR ( _S3 ) connected between the voltage dividing point _P5 and the negative line _LN , which starts when the ambient temperature at the start of charging is below the boundary value; It consists of an SCR gate circuit G. The gate circuit is composed of a series circuit of a resistor R ₂ and a resistor R ₃ in which a diode D ₁₀ and a capacitor C ₂ are connected in parallel.
Voltage dividing point P ₃ is connected to the gate of SCR (S ₃ ). When battery B reaches a predetermined charging voltage, the sixth transistor
A seventh transistor _Q7 is connected in series with the relay coil _RY , and the positive and negative lines are connected in series with the relay coil RY.
Connected between L _p and L _N.

In the above configuration, if the ambient temperature at the start of charging is below the boundary temperature, the first thermostat _H1
will be developed. On the other hand, since the battery voltage is still low, the sixth transistor _Q6 is cut off, and the relay coil RY is energized due to the conduction of the seventh transistor _Q7 . Therefore, relay switch RW is closed. Also, since the charging current of capacitor _C3 flows into the gate of SCR (S ₄ ), ignition conduction occurs and SCR (S ₄ )
The conduction state of is maintained by the smoothing voltage of the smoothing capacitor _C1 . Therefore, battery B has closed second thermostat H ₂ , relay switch RW and
Charged via SCR (S ₄ ).

When the battery voltage reaches the predetermined charging voltage, the sixth transistor _Q6 becomes conductive as described above, so the seventh transistor _Q7 is cut off, and the relay coil RY is no longer energized, so the relay switch RW is opened.
Battery charging ends.

Next, when the ambient temperature at the start of charging is higher than the boundary temperature, the first thermostat _H1 is closed, and the charging current of the capacitor _C2 flows into the gate of the SCR ( _S3 ), and the SCR is Ignition conducts. Since this conduction state is maintained by the smoothed output of the smoothing capacitor _C1 , the sixth
Transistor Q ₆ is blocking. For this reason, the seventh
Transistor Q ₇ is conducting and the relay coil
Relay switch RW is closed due to the excitation of RY. Further, the SCR (S ₄ ) is turned on by the charging current of the capacitor C ₃ and kept conductive by the output of the smoothing capacitor C ₁ .

In this state, battery B is connected to the second thermostat H ₂ ,
Charged via relay switch RW and SCR (S ₄ ). At this time, the temperature of the battery rises from near full charge, and when it reaches a predetermined temperature rise, the temperature detection means TD
The second thermostat _H2 , which constitutes the battery, is opened and charging of the battery is completed. The battery temperature decreases as charging ends, but when the second thermostat H ₂ opens, the SCR (S ₄ ) shuts off. Applicable in this case
Since the gate of the SCR is given a negative voltage by the capacitor C ₃ , the SCR (S ₄ ) is kept in a cut-off state.

In FIGS. 2 and 3, a diode _D11 is connected in parallel to the second thermostat _H2 . The diode connects the battery pack Y to the load and prevents the load current from being cut off when the load current is large due to a rise in battery temperature and opening of the second thermostat _H2 .

Furthermore, in the embodiment, a battery is used as the rechargeable battery B, in which the temperature of the battery's outer case rises rapidly due to a charging chemical reaction. An example of a specific structure of such a battery will be explained based on FIG. 4. This figure is a cross-sectional view of a spiral electrode body as the internal structure of a battery. In this figure, 11 is a main separator, and an auxiliary separator 1 is located in the center of the main separator.
2 attached thereto and wound so that the separator 11 or 11, 12 is interposed between the anode plate 13, which is a nickel sintered substrate filled with nickel hydroxide, and the cathode plate 14, which is a nickel sintered substrate filled with cadmium hydroxide. A spiral electrode body is constructed by using a spiral electrode body. In this case, since the separator is doubled at the center, the gas permeability of the separator is worse than that at the outer periphery, and the above-mentioned charging chemical reaction becomes active at the outer periphery, causing a rapid rise in the temperature of the outer can. become.
In Fig. 4, the separator has a double structure in order to reduce the gas permeability in the center of the separator. It may be crushed.

As described above, according to the present invention, depending on whether the ambient temperature at the start of charging is in a low temperature range or a high temperature range,
Since the voltage detecting means for detecting a predetermined charging voltage of the battery to be charged and the temperature detecting means for detecting a predetermined temperature rise of the battery are operated selectively, battery Even if the characteristics of the batteries are different, the battery can be properly charged. In addition, if the battery to be charged is one in which the temperature of the outer can rises rapidly due to a charging chemical reaction, the temperature of the outer can can be easily detected and there is no time delay in detecting the temperature of the outer can. Deterioration can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a voltage characteristic diagram of a battery, FIGS. 2 and 3 are circuit diagrams of different embodiments of the device according to the invention, and FIG.
The figure is a cross-sectional view of a spiral electrode body of a battery to be charged. B...Battery to be charged, TD...Temperature detection means,
VD... Voltage detection means, H ₁ ... Heat sensitive element.

Claims (1)

[Scope of Claims] 1. A battery charging device comprising temperature detection means for detecting a predetermined temperature rise of a battery to be charged, and voltage detection means for detecting a predetermined charging voltage of the battery, comprising:
A battery charging device characterized in that the voltage detection means has a heat-sensitive element that detects a low temperature range of ambient temperature, and the voltage detection means is operated only in the low temperature range. 2. The battery charging device according to claim 1, wherein the battery is a battery whose outer can has a rapid temperature rise due to a charging chemical reaction.