JP3764175B2 - Power storage device - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a power storage device that stores electric power in a capacitor block configured by connecting a plurality of electric double layer capacitors and the like in series and parallel and supplies power to a load.
[0002]
[Prior art]
Exhaust gas from automobiles equipped with gasoline engines has been discussed as a subject of regulation for a long time due to environmental problems on a global scale. In reality, however, the production volume of automobiles continues to increase, but there is no prospect that automobile exhaust emissions can be reduced. Under such circumstances, electric vehicles equipped with batteries and solar cells are attracting attention as vehicles without exhaust gas, and their early practical use is an urgent issue.
[0003]
In recent years, some electric vehicles have been put into practical use for commercial vehicles such as delivery vehicles and cleaning vehicles that do not require a long continuous travel distance or high-speed travel. In addition, as a prototype vehicle, a vehicle capable of traveling at a high speed of 100 km / h or more and continuously traveling at about 200 km has been reported. In addition, vehicles that run while charging a battery with a solar cell mounted on the vehicle, vehicles that are hybrid driven by an engine and a motor, and the like have been proposed.
[0004]
[Problems to be solved by the invention]
In the electric vehicle, an independent four-wheel drive using a wheel motor without a gear mechanism like an engine vehicle is one direction. In this case, the drive mechanism is simplified, and traveling performance and steering performance can be solved by cooperative control of the wheel motors. The biggest technical challenge in electric vehicles is the realization of a drive power source, that is, a battery with a capacity comparable to that of an engine vehicle. First, in order to be sufficiently put into practical use as an electric vehicle, a battery having the same size and weight as an engine and a capacity capable of securing power comparable to a gasoline engine is required. Moreover, it is possible to replace the charged battery as easily as charging gasoline or charging it at a high speed.
[0005]
However, none of the conventional batteries satisfy the above requirements. In particular, not only does it take a long time to charge, but the problem is that it is larger and heavier than the engine.
[0006]
In addition, electric double-layer capacitors that are smaller and have a larger capacity than conventional capacitors have been developed and tend to be used for power backup and the like. A large-capacitance capacitor such as this electric double layer capacitor is advantageous in terms of light weight and long life compared to a lead battery when considered as a power storage power source, but when the applied voltage becomes excessive relative to the rating, Immediate damage to capacitors such as decreased capacitance and increased leakage current. In addition, since the internal resistance and withstand voltage are insufficiently controlled, they have not been actively used.
[0007]
Furthermore, when charging a secondary battery, it has been difficult to accurately detect the completion of charging or to measure how much electricity can be used from the battery at that time.
[0008]
For example, there are various methods for detecting the completion of charging, such as setting the end voltage to a constant value, estimating from the amount of electricity that has flowed in, and capturing the moment when the voltage slightly dip due to the temperature characteristics of the battery after charging for a certain time. Although it has been devised, nevertheless, the charging characteristics vary variously depending on the state of the battery, such as whether the battery is new or old, the state of aging, the charging current, whether the battery is continuously used or charged.
[0009]
In addition, as a method of measuring the remaining amount, various devices have been made such as measuring the terminal voltage under a constant load, calculating from the charged and discharged amount of electricity, and estimating from the temperature and specific gravity of the electrolyte. However, the characteristics of the battery change variously depending on the quality of the battery, old and new, usage history, load and charging conditions.
[0010]
As described above, there are almost no methods for always accurately detecting the full charge point and methods for always accurately detecting the remaining battery level. Moreover, in order to use the battery capacity effectively, a certain amount of overcharge is usually performed, and it is indispensable to know the remaining battery capacity. In the future when the use of secondary batteries becomes commonplace due to the practical use of electric vehicles, etc., the waste of electric energy caused by overcharging becomes a problem that cannot be ignored, and depending on whether you can know how much you can run further, the battery Is expected to take even more practical use.
[0011]
The present invention solves the above-described problems, and an object of the present invention is to provide a power storage device that can be rapidly charged with a stable supply voltage to a load, has a long life, and is lightweight. Another object of the present invention is to provide a power storage device capable of storing electricity with high efficiency using a capacitor and supplying power to a load. Still another object of the present invention is to provide a power storage device capable of accurately detecting the point of full charge and eliminating unnecessary overcharge and insufficient charge. Still another object of the present invention is to provide a power storage device that can accurately measure the remaining amount and know a reliable operation limit.
[0012]
Therefore, the present invention is a power storage device that stores power in a capacitor block configured by connecting a plurality of capacitors in series and parallel and supplies power to a load, and is connected to each of the plurality of capacitors in parallel. A plurality of parallel monitors that detect a terminal voltage, determine that the terminal voltage has reached a predetermined value, and bypass charging current at the predetermined value; charging means that charges the capacitor block; and a plurality of parallel monitors. The charging state of the entire capacitor block is determined from the bypass operation, and charging of the capacitor block by the charging means is performed. Finish To charge Finish Means.
[0013]
Charge Finish The means logically processes the operation signals of a plurality of parallel monitors bypassing the charging current to determine the state of charge, and determines the state of charge from the operation signals of a specific parallel monitor among the plurality of parallel monitors. And the charging means includes means for superimposing an AC waveform on the charging current, and the charging Finish The means is characterized in that the state of charge is determined by monitoring the amplitude of the AC waveform and detecting the bypass operation of each parallel monitor.
[0014]
Further, the charging means has a remaining amount detection circuit comprising a multiplication circuit that takes out and squares the terminal voltage of the capacitor block or the specific capacitor and an arithmetic circuit that multiplies the constant, and the terminal voltage of the capacitor block or the specific capacitor Is applied to the series circuit of the constant voltage circuit and the detection element, and the remaining amount detection circuit detects the current corresponding to the remaining amount by the detection element, and has a large internal resistance and power capacity with respect to the capacitor block. A second capacitor block having a large ratio with respect to volume or weight is provided as a charging power source for the capacitor block.
[0015]
[Action]
In the power storage device of the present invention, a capacitor block that is connected to a load and supplies power directly to the load, a charging circuit that charges the capacitor block, a charging power source that is connected to the capacitor block through the charging circuit, and a terminal of each capacitor Since the voltage is detected and the charge limit circuit determines that the terminal voltage has reached a predetermined value and the charging of the condenser is limited, the capacitor block can be used up to the designed maximum voltage, and the electrical energy storage Efficiency can be increased.
[0016]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram showing an embodiment of a power storage device according to the present invention, in which 1 is a power source for charging, 2 is a charging circuit, 3 is a voltage detection circuit, 4 is a load, C is a large capacity capacitor, Vr, Vr ′ Is a reference voltage, and S1 and S2 are switches.
[0017]
In FIG. 1, a large-capacitance capacitor C is connected to a charging power source 1 through a switch S <b> 1 and a charging circuit 2 and is connected to a load 4, and supplies power directly to the load 4. The charging power source 1 is, for example, a commercial power source for charging the large-capacity capacitor C, and the charging circuit 2 includes voltage conversion means such as an inverter. The voltage detection circuit 3 detects whether or not the terminal voltage of the large-capacitance capacitor C is at a full charge level as compared with the reference voltages Vr and Vr ′. When the voltage detection circuit 3 reaches the full charge level, the switch S1 is turned off and the switch Turn on S2. Therefore, by setting the reference voltage Vr + Vr ′ to the full charge level, the switch S1 is kept on until the terminal voltage of the large-capacitance capacitor C reaches the full charge level, and the charging power source is supplied via the charging circuit 2. When the large-capacity capacitor C is charged from 1 and the full charge level is reached, the switch S1 is turned off to stop charging, and the voltage applied to the large-capacitance capacitor C is prevented from becoming excessive with respect to the rating. At this time, a certain dead band is set for the on / off control of the switch S1 by turning on the switch S2 and short-circuiting a part of the reference voltage Vr ′.
[0018]
As described above, when a capacitor is used as a power source, if the applied voltage becomes excessive with respect to the rating of the capacitor, damages such as a decrease in the capacitance of the capacitor and an increase in leakage current occur immediately. In order to deal with this, the capacitor side is usually designed and manufactured with a margin for the decomposition voltage, withstand voltage, and the like. However, since the electrical energy stored in the capacitor is proportional to the square of the voltage, it is advantageous to use even a little higher voltage. From this point of view, in the present invention, since the terminal voltage of the capacitor is constantly monitored and limited by the switch S1, the capacitor can be used up to its full voltage, and more electrical energy can be stored effectively.
[0019]
FIG. 2 is a diagram showing another embodiment of the power storage device according to the present invention. ZD is a constant voltage element, TR is a transistor, and R1 and R2 are resistors.
In the embodiment shown in FIG. 2, a series circuit of a transistor TR and a resistor R2 is connected as a bypass circuit for the charging current of the large-capacitance capacitor C so that the terminal voltage of the large-capacitance capacitor C is limited to the voltage of the constant voltage element ZD. It is composed. With this configuration, when the voltage of the constant voltage element ZD is selected as the voltage when the large-capacitance capacitor C is at the full charge level, the transistor TR is turned on at the full charge level, and the terminal voltage of the large-capacitance capacitor C is maintained at the full charge level. As a result, the conductivity of the transistor TR changes. That is, a voltage limiter is configured.
[0020]
FIG. 3 is a diagram showing still another embodiment of the power storage device according to the present invention, in which 11 is a charging AC power source, 12 is a charging DC power source, 13 to 15 are charging circuits, 16 is a charging control circuit, and 17 is a charging control circuit. A load, A and B are capacitor blocks, and Vr is a reference voltage.
[0021]
In FIG. 3, a capacitor block A is a power supply for load power supply that is connected to a load 17 and directly supplies power to the load 17, and uses a large-capacity capacitor having a low internal resistance although the power density is not so high. The capacitor block B is a power source for charging the capacitor block A, and a large-capacity capacitor having a large ratio of the power capacity to the volume or weight is used, although the internal resistance is not so low as compared with the capacitor block A. The charging circuit 15 is a circuit that charges the capacitor block A from the capacitor block B, and is configured by voltage conversion means such as an inverter. The charging control circuit 16 detects the terminal voltage of the capacitor block A, that is, the load voltage, compares it with the reference voltage Vr, and in the case of the reference voltage Vr, the charging circuit 15 charges the capacitor block A from the capacitor block B. Is to control. The reference voltage Vr is set to the full charge level of the capacitor block A.
[0022]
The charging AC power supply 11 is, for example, a normal commercial AC power supply, and the charging DC power supply 12 is, for example, a DC power supply such as a solar battery. The charging circuits 13 and 14 are circuits that charge the capacitor block B by voltage conversion and rectification. Of course, the charging circuits 13 and 14 may be constituted by voltage conversion means such as an inverter.
[0023]
As described above, the necessary power supply capacity is divided into two power supply units composed of the capacitor block A and the capacitor block B, and varies depending on the conditions such as the load. For example, the capacitor block A is 1/4 of the total capacity, and the capacitor block B The remaining capacity is 3/4. By keeping the capacitor block A at a fully charged level as much as possible, the load can always be supplied with a relatively constant voltage from a power source (capacitor block A) having a low internal resistance. Since the power source (capacitor block B) having a large internal resistance is used frequently, the entire volume and weight can be reduced.
[0024]
FIG. 4 is a diagram illustrating a configuration example of the charging control unit. The comparator 21 compares the terminal voltage of the capacitor block A with the reference voltage Vr, and outputs a signal for turning on the charging circuit 15 when the reference voltage Vr is large. The terminal voltage of the capacitor block A is divided and detected by the resistors R1 and R2, and a detection signal of the terminal voltage is input to the comparator 21 via the resistor R13. As described later, a charge limiting circuit may be provided for each capacitor of the capacitor block A to detect full charge. The resistor r is a resistor for current detection. The charging circuit 15 detects the charging current with the resistor r and controls the charging current to be constant. That is, the charging circuit 15 is turned on / off by the output signal of the comparator 21 and controls the charging current by detecting the current by the resistor r. The capacitor block B is a power source having a large internal resistance, and loss is increased when charged with a large current. Therefore, the loss is reduced by limiting the charging current.
[0025]
Next, the electric double layer capacitor used in the present invention will be described.
An electric double layer capacitor uses an activated carbon which has a large specific surface area and is electrochemically inert as an electrode material, and uses a large electric double layer capacity in combination with an electrolyte. Until the decomposition voltage of the electrolyte is reached, the electric double layer is formed and charged, and when the decomposition voltage is exceeded, current begins to flow. Therefore, the withstand voltage of the electric double layer capacitor is regulated by the decomposition voltage of the electrolyte, and the decomposition voltage of the aqueous electrolyte having high conductivity is about 1.23V. Electric double layer capacitors with a withstand voltage of several volts and a capacity of several F (farad) are commercially available, and there are various internal resistances ranging from 100Ω to 10Ω, but recent prototypes include: 2.5V, 240F, 0.1Ω are announced.
[0026]
As described above, the conventional electric double layer capacitor has a difficulty in having a low withstand voltage and a small amount of electricity when used as an electricity storage power source. In addition, compared with electrochemical cells such as lead batteries and nickel cadmium batteries, even in electric double layer capacitors, the latter is about 20 times larger due to the relationship between weight and energy, and the internal resistance is large. I can not use it. Therefore, in order for the electric double layer capacitor to compete with the storage battery, basically, the energy density is increased and the internal resistance is decreased.
[0027]
In general, when a voltage higher than the decomposition voltage is applied to the capacitor, it causes damage such as a decrease in capacity and an increase in leakage current. Therefore, a voltage equal to or lower than the decomposition voltage is used as the withstand voltage. This decomposition voltage is about 1.23 V in the case of water and about 1.5 to 2.5 V in the case of a commonly used organic electrolyte. On the other hand, many organic materials have a decomposition voltage of 6 V or more among organic electrolytes. However, when actually used in an electric double layer capacitor, the withstand voltage has a rating of 1.5 to 2.5V. This is thought to be due to impurities including water.
[0028]
On the other hand, porous materials such as activated carbon and activated carbon fibers adsorb various foreign substances in their natural state. If these are used as they are, various foreign substances will be generated when the electrode is immersed in an electrolyte. Elutes in the electrolyte. Therefore, even if the high purity electrolytic solution is purified as described above, the purity is lowered and the decomposition voltage is lowered. Thus, for example, if the electrode is evacuated while being heated at high frequency in a vacuum vessel in advance, and then cooled as it is and vacuum impregnated in the electrolytic solution, foreign substances can be removed, and a decrease in the purity of the electrolytic solution can be prevented.
[0029]
Moreover, as an electrode structure for increasing the capacitance and reducing the internal resistance, for example, activated carbon fibers are activated slightly excessively to obtain fibers having slightly larger microbore. Then, these fibers are aligned and arranged almost in close contact with each other in a plate shape, and a metal such as aluminum is vapor-deposited or sprayed on both ends and the back surface thereof or connected with a conductive paint or the like to attach a lead wire. As a result, an electrode having a low electrical resistance and a high density can be obtained. These electrodes are impregnated with an electrolytic solution and are opposed to each other through an insulating porous separator, and used as positive and negative electrodes.
[0030]
As described above, by refining the electrolyte and manufacturing and assembling the activated carbon electrode, an electric double layer capacitor having a high withstand voltage can be obtained, and the internal resistance can be reduced. As a result, when the withstand voltage is increased, for example, twice, the amount of power that can be stored can be increased to four times the square. For example, the 2.5V, 240F, 0.1Ω electric double layer capacitor prototype described above has a volume of 35 mmφ × 50 mm and the electric power that can be extracted up to 1V is 0.175 WH. To secure the power of 20 KWH required for ^Three Is required. However, for example, the volume can be reduced to ¼ simply by increasing the withstand voltage twice. Furthermore, mounting efficiency (filling rate) exceeds 2.5 times, and if the improvement of about 2 times is achieved with the present invention using the charge limiting circuit and two capacitor blocks, it will exceed 20 times, including the possibility of an increase in capacitance. The amount of electric power can be increased. In the present invention, such an electric double layer capacitor is selectively used, so that the stored electric energy can be increased, the internal resistance can be reduced, the power loss can be reduced, and the power supply efficiency can be increased.
[0031]
In the above description, the configuration in which charge control is performed for each capacitor block has been described. However, since the withstand voltage of the electric double layer capacitor is as low as 2.5 to 5 V, it is used in series for applications used for power. Is done. At that time, if the voltage applied to each capacitor is different, it is necessary to be careful that the smallest capacitor among them is damaged beyond the rating in order or that it is used in a voltage range sufficiently lower than the rating to avoid it. Become. In such a case, if a charge limiting circuit is provided for all capacitors, when a plurality of these capacitors are used in series and the capacitor reaches the rating, the charge limiting circuit connected to the capacitor will bypass the bypass circuit. When turned on, no voltage exceeding the rating will be applied to any capacitor, so you can use it to the full rating. The power storage device of the present invention using an electric double layer capacitor monitors the voltage of each cell as described above, and inserts a charge limiting circuit into each cell in order to make it uniform. Next, specific examples of the charge limiting circuit and the full charge detection circuit will be described.
[0032]
FIG. 5 is a diagram showing an embodiment of a full charge detection circuit with a charge limiting circuit inserted therein, FIG. 6 is a diagram showing an analysis result by simulation of the full charge detection circuit shown in FIG. 5, and FIG. FIG. 8 is a diagram showing an example of a circuit, FIG. 8 is a diagram showing an embodiment of a full-charge detection circuit having a two-stage configuration, and FIG. 9 is a diagram showing an analysis result by simulation of the full-charge detection circuit shown in FIG.
[0033]
In FIG. 5, an electric double layer capacitor C1 having an internal resistance R1 includes a charge limiting circuit (hereinafter also referred to as a parallel monitor) including a three-terminal shunt regulator ICX1, a transistor Q1, a Schottky diode D1, and resistors R2 to R5 in parallel. And a differential circuit composed of CT and RT are connected, and when charged from the charging power supply I1, when full charge is reached, the current is bypassed by the charge limiting circuit, and full charge is detected by the differential circuit. This full charge detection is performed by superimposing an AC waveform on the charging power source I1.
[0034]
The terminal voltage in a state where the electric double layer capacitor for electric power having an electrostatic capacity of 300 F, a withstand voltage of 50 V, and an electric capacity of 100 Wh is charged from a completely discharged state with a charging current of 2 A is shown in FIG. ), I (R5) in FIG. 6 shows the current flowing through the resistor R5 of the charge limiting circuit, and V (9) in FIG. 6 shows the terminal voltage at the resistor RT of the differentiating circuit, and the frequency is 10 mHz. A current ripple with an amplitude of 0.5 A is superimposed. This abnormally low ripple frequency is for easy viewing on the waveform diagram of the analysis result. In practice, a ripple from a rectifier circuit for a commercial AC power supply may be used. According to FIG. 6, when the charging voltage reaches nearly 50V around the charging time of 7400 seconds and the charging limiting circuit is turned on, the current I (5) flowing through the resistor R5 and the terminal voltage V (9) at the resistor RT are Also shows a drastic change. Therefore, full charge can be easily known by detecting this.
[0035]
The configuration shown in FIG. 7 is provided for electric power use, and the charge limiting circuits R2 to R5, X1, Q1, D11 and R12 to R15, X11, Q11, and D11 are connected in series with the electric double layer capacitors C1 and C11. When each capacitor reaches the rating, the charge limiting circuit connected to the capacitor turns on the bypass circuit so that no voltage exceeding the rating is applied to any capacitor. By doing in this way, the voltage of each cell can be monitored and equalized, and it can be used safely to the full rating. In addition, as shown in FIG. 8, full charge can be accurately captured by detecting a state in which all the charge limiting circuits connected in series with the differentiating circuit composed of CT and RT are turned on.
[0036]
In the configuration shown in FIG. 8 in which two electric double layer capacitors C1 and C11 are connected in series, these two electric double layer capacitors C1 and C11 are both set to 25V and 600F, and the set values of the charge limiting circuit are deliberately shifted, respectively. FIG. 9 shows an example of a simulation analysis result of about 24V and 23V. According to the result, as shown in FIG. 9, the entire charging voltage V (1) is bent at the end of charging, and the terminal voltage V (9) at the resistor RT of the differentiating circuit and the resistor R5 of the charging limiting circuit. By observing the flowing current I (5), it can be clearly seen that one reaches full charge and then the other reaches full charge.
[0037]
From the above, there are the following methods for detecting the full charge of the power storage device in which a plurality of electric double layer capacitors are connected in series. First, one takes out signals from all the charge limiting circuits attached to each capacitor, calculates the logical sum of them, detects a state where all have reached the rating, and uses it as a full charge. Second, the operating points of all the charge limiting circuits attached to each capacitor are configured in advance so as to be within a certain error, for example, 5% by using a test inspection or quality control method. Select an individual and make it fully charged with the operating point of its charge limiting circuit. Third, an AC waveform or a pulse waveform is preliminarily superimposed on a constant current circuit or pseudo constant current circuit used for charging the capacitor, and the amplitude is monitored to detect full charge. In this case, the amplitude decreases suddenly when all capacitors connected as loads reach full charge and all charge limiting circuits turn on the bypass circuit, so this point is detected and fully charged. .
[0038]
Next, the remaining amount detection applied to the power storage device of the present invention will be described. In the electricity storage power supply device of the present invention using an electric double layer capacitor, it is rare that the electric power storage device is normally constructed using only one electric double layer capacitor. As described with reference to FIG. A double layer capacitor is configured in series or in a block in which serially connected capacitors are further connected in parallel. In this case, if the capacity of the capacitor block A is Ca, the voltage is Va, and the capacity and voltage of the capacitor block B are Cb and Vb, respectively, the remaining amount W is
W = 0.5 · Ca · Va · Va + 0.5 · Cb · Vb · Vb (1)
Is required. Therefore, if the voltages Va and Vb of the capacitor blocks A and B are measured and the values are introduced into a circuit that performs the above calculation, a highly accurate remaining amount can be obtained.
[0039]
FIG. 10 is a diagram showing one embodiment of a remaining amount detection circuit applied to the power storage device of the present invention, and FIG. 11 is a diagram showing an analysis result by simulation of charge / discharge characteristics. In FIG. 10A, a signal indicating the remaining amount is generated by calculating the square of V by the multiplier X1 and multiplying it by a constant by the operational amplifier U2, and the remaining amount of a plurality of electric double layer capacitors and capacitor blocks. Is detected, if a multiplier X1 and a resistor R2 are respectively provided and connected to the node 3, the total remaining amount signal can be extracted from the output of the operational amplifier U2. FIG. 10B shows a configuration in which a resistor R5, a light emitting diode D1, and a Zener diode D2 are connected in series with respect to the electric double layer capacitor C2 and its internal resistance R4 so that an approximate remaining amount is displayed according to light intensity. It is. In this case, the resistor R5 is a current limiting resistor that adjusts the gradient, that is, the brightness of the light emitting diode D1, but, of course, an indicator may be used instead of the light emitting diode D1, and the Zener diode has a constant voltage. Other constant voltage elements or constant voltage sources may be used as long as they constitute a circuit.
[0040]
In an electric double layer capacitor having an electrostatic capacity of 300 F, a withstand voltage of 50 V, and an electric capacity of about 100 Wh, A in FIG. 11 shows a terminal voltage in a state where charging is performed with a charging current of 2 A from a completely discharged state. B indicates the remaining amount calculated from the above equation, and 0.5 × 300 × 49 × 49, about 360 kJ, that is, 100 Wh is the instruction value of the remaining amount meter. In addition, C in FIG. 11 is obtained by superimposing a straight line on B, and this characteristic can be obtained by connecting a Zener diode of about 18 V in series with the terminal voltage V (1). It can be seen that the remaining amount can be obtained with a fairly good accuracy within the range.
[0041]
In addition, this invention is not limited to said Example, A various deformation | transformation is possible. For example, in the above embodiment, the circuit on / off means is simply shown as a switch. However, a semiconductor switching element such as a thyristor or a transistor, or other switching means may be used. Needless to say, it may be used not only as a power source for an electric vehicle but also as a power source for an electric welder or other electric power device, a portable electric device such as a flashlight, a notebook personal computer or the like.
[0042]
【The invention's effect】
As is clear from the above description, according to the present invention, the charging of the capacitor is controlled by the terminal voltage and charged to the full charge level, so that electric energy can be effectively stored, and the supply efficiency as a power storage power supply device Can be increased. Further, since it is possible to prevent an excessive voltage from being applied to the capacitor, it is possible to prevent damage such as a decrease in the capacitance of the capacitor and an increase in leakage current even when the capacitor is used as a power storage power source.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of a power storage device according to the present invention.
FIG. 2 is a diagram showing another embodiment of the power storage device according to the present invention.
FIG. 3 is a diagram showing still another embodiment of the power storage device according to the present invention.
FIG. 4 is a diagram illustrating a configuration example of a charge control unit.
FIG. 5 is a diagram showing one embodiment of a full charge detection circuit in which a charge limiting circuit is inserted.
6 is a diagram showing an analysis result by simulation of the full charge detection circuit shown in FIG. 5;
FIG. 7 is a diagram illustrating an example of a charge limiting circuit having a two-stage configuration.
FIG. 8 is a diagram illustrating an embodiment of a full charge detection circuit having a two-stage configuration.
9 is a diagram showing an analysis result by simulation of the full charge detection circuit shown in FIG. 8;
FIG. 10 is a diagram showing one embodiment of a remaining amount detection circuit applied to the power storage device of the present invention.
FIG. 11 is a diagram showing an analysis result by simulation of charge / discharge characteristics.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Power supply for charge, 2 ... Charging circuit, 3 ... Voltage detection circuit, 4 ... Load, C ... Large capacity capacitor, Vr, Vr '... Reference voltage, S1, S2 ... Switch

Claims (7)

A power storage device that stores power in a capacitor block configured by connecting a plurality of capacitors in series and parallel and supplies power to a load,
A plurality of parallel monitors connected in parallel to each of the plurality of capacitors to detect a terminal voltage of the capacitor, determine that the terminal voltage has reached a predetermined value, and bypass the charging current at the predetermined value;
Charging means for charging the capacitor block;
A power storage device comprising: charge ending means for determining a charging state of the entire capacitor block from bypass operations of the plurality of parallel monitors and ending charging of the capacitor block by the charging means. 2. The power storage device according to claim 1, wherein the charging end unit logically processes operation signals of a plurality of parallel monitors that bypass the charging current to determine the charging state. 2. The power storage device according to claim 1, wherein the charging end unit determines the state of charge from an operation signal of a specific parallel monitor among the plurality of parallel monitors. The charging unit includes a unit that superimposes an AC waveform on the charging current, and the charging end unit determines a charging state by monitoring an amplitude of the AC waveform and detecting a bypass operation of each parallel monitor. The power storage device according to claim 1.   5. The charging unit according to claim 1, further comprising: a remaining amount detection circuit including a multiplication circuit that takes out and squares a terminal voltage of the capacitor block or a specific capacitor and an arithmetic circuit that multiplies the constant. The electrical storage power supply apparatus of description.   The charging unit has a remaining amount detection circuit that takes out a terminal voltage of the capacitor block or a specific capacitor, applies the detected voltage to a series circuit of a constant voltage circuit and a detection element, and detects a current corresponding to the remaining amount by the detection element. The power storage device according to any one of claims 1 to 4.   7. The charging unit according to claim 1, wherein the charging unit includes a second capacitor block having a large internal resistance with respect to the capacitor block and a large ratio of power capacity to volume or weight as a charging power source for the capacitor block. The power storage device according to any one of the above.

Images