JP2010110124A - Power system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power system in which a plurality of secondary batteries are connected, and which provides the optimum capacity even if the system has a large capacity. <P>SOLUTION: The power system is provided with: a main secondary battery block Bm containing a secondary battery train in which N (N is a natural number) pieces of secondary batteries are connected in series; an auxiliary secondary battery block Bs containing a secondary battery train in which A (A is a natural number and N>A) pieces of secondary batteries are connected in series; and a DC-DC converter Uvc which performs voltage conversion between the main secondary battery block Bm and the auxiliary secondary battery block Bs. The DC-DC converter Uvc steps up a voltage of the auxiliary secondary battery block Bs in discharging so as to supply electric power to a load, and steps down the voltage of the main secondary battery block Bm in charging so as to supply electric power to the auxiliary secondary battery block Bs. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a power supply system, and more particularly, to a power supply system in which a plurality of chargeable / dischargeable secondary batteries or a plurality of capacitors (capacitors) are connected in series and / or in parallel.

  15 to 18 are circuit diagrams showing configuration examples of the power supply system studied as a premise of the present invention. The power supply system shown in FIG. 15 is obtained by connecting N secondary batteries in series. The power supply system shown in FIG. 16 is configured to connect X secondary batteries in series, convert the voltage with a DC-DC converter, and supply a desired voltage to a load. In the case of the configuration of FIG. 16, power loss occurs, and thus efficiency decreases. The power supply system shown in FIG. 17 is a system in which M secondary battery blocks in which N secondary batteries are connected in series are connected in parallel. In the case of the configuration of FIG. 17, the number of series connections in each secondary battery block is the same in order to maintain the balance during charging and discharging of each secondary battery. FIG. 18 shows a configuration in which N balance circuits are connected to the power supply system shown in FIG. As shown in FIG. 18, when the number of secondary battery blocks connected in series is N, N balance circuits are required.

  In addition, as a technique regarding such a power supply system, for example, there are techniques described in Patent Document 1 and Patent Document 2. The secondary battery charging device described in Patent Document 1 includes a plurality of secondary batteries connected in series to form a secondary battery series circuit, and a plurality of the series circuits connected in parallel to form a secondary battery. A means for detecting a battery voltage of each secondary battery in the series circuit, a means for detecting a charging current for each parallel circuit, and a charging current for each battery of the secondary battery in the series circuit are configured. Means for controlling and means for controlling the charge output for each parallel circuit are provided. Moreover, the power supply device described in Patent Document 2 has a plurality of series-connected battery blocks in which a plurality of secondary batteries are connected in series, connected in parallel, and each of the series-connected battery blocks is provided with a constant current control circuit. It is.

Japanese Patent Laid-Open No. 10-304586 JP 2006-345660 A

  By the way, as a result of the study of the power supply system technology as described above, the following has been clarified.

  For example, when connecting secondary battery blocks connected in series, the number of secondary batteries connected in series is the same as in Patent Document 1 and Patent Document 2, and each block is balanced. It was something like that. Therefore, since all the secondary battery blocks connected in parallel have the same number in series, there is a problem that the flexibility of the total battery block capacity is lost as the capacity increases.

  In particular, spacecraft such as artificial satellites require a large-capacity secondary battery system, but the types of batteries that can be used in space are limited, and sometimes a secondary battery system with an excess capacity than necessary is required. It was supposed to be installed. As a result, there is a problem that the weight of the battery increases.

  In addition, in order to realize a configuration close to the required capacity, when using a plurality of secondary batteries having relatively low capacity, the number of secondary batteries increases, so that the overall cost is high. .

  Accordingly, an object of the present invention is to provide a power supply system having an optimum capacity even in a large capacity in a power supply system in which a plurality of secondary batteries are connected. Another object of the present invention is to realize a lightweight power supply system.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows.
That is, the power supply system according to the present invention includes a first secondary battery block (main secondary battery block) including a secondary battery array in which N (N is a natural number) secondary batteries are connected in series, and A pieces. A second secondary battery block (auxiliary secondary battery block) including a secondary battery array in which secondary batteries (N> A and A are natural numbers) are connected in series; and the first secondary battery block; And a control circuit that performs voltage conversion with the second secondary battery block, and both electrodes of the first secondary battery block are connected to a load.

Of the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows.
(1) Since it is possible to realize a flexible battery capacity, it is not necessary to have a surplus capacity, so that an inexpensive and lightweight power supply system can be provided.
(2) The voltage balance of the secondary batteries of the main secondary battery block and the auxiliary secondary battery block can always be maintained.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment, and the repetitive description thereof will be omitted. Unless otherwise specified, a symbol representing a terminal name also serves as a wiring name and a signal name, and also serves as a voltage value in the case of a power supply.

  In the following embodiment, when it is necessary for the sake of convenience, the description will be divided into a plurality of sections or embodiments. However, unless otherwise specified, they are not irrelevant, and one is the other. Some or all of the modifications, details, supplementary explanations, and the like are related. Further, in the following embodiments, when referring to the number of elements (including the number, numerical value, quantity, range, etc.), especially when clearly indicated and when clearly limited to a specific number in principle, etc. Except, it is not limited to the specific number, and may be more or less than the specific number.

(Embodiment 1)
1 is a circuit diagram showing a configuration example of a power supply system according to Embodiment 1 of the present invention, FIG. 2 is a circuit diagram showing a configuration example of the DC-DC converter shown in FIG. 1, and FIG. 3 is an embodiment of the present invention. 1 is a circuit diagram illustrating a connection example of a secondary battery balance circuit in the power supply system according to FIG.

  First, an example of the configuration of the power supply system according to the first embodiment will be described with reference to FIG. The power supply system according to the first embodiment includes, for example, a main secondary battery block Bm, an auxiliary secondary battery block Bs, a DC-DC converter (control circuit) Uvc, and the like. The main secondary battery block Bm is configured by connecting N secondary batteries in series. Moreover, the auxiliary secondary battery block Bs is configured by a parallel connection of a battery blocks composed of A secondary batteries connected in series. N, A, and a are natural numbers and have a relationship of N> A. Moreover, the secondary battery which comprises the main secondary battery block Bm and the auxiliary secondary battery block Bs is a secondary battery which can be charged / discharged, such as a lithium ion battery, for example. Further, instead of the secondary battery, a large capacity capacitor (capacitor or the like) such as a lithium ion capacitor may be used.

  As shown in FIG. 1, the main secondary battery block Bm and the auxiliary secondary battery block Bs are connected in parallel via the DC-DC converter Uvc. Further, the main secondary battery block Bm can be configured by connecting a plurality of blocks composed of N secondary batteries connected in series in parallel. Further, the auxiliary secondary battery block Bs may be a = 1, that is, only one row of A secondary batteries connected in series.

  The power supply system of the first embodiment includes two secondary battery blocks having different voltages, for example, a main secondary battery block Bm and an auxiliary secondary battery block Bs having a lower voltage than the main secondary battery block Bm. It is configured as. The auxiliary secondary battery block Bs is stepped up / down by the DC-DC converter Uvc to realize the output of the main secondary battery block + α. The main secondary battery block Bm lacking the target capacity and the auxiliary secondary battery block Bs for compensating for the shortage are constituted by a circuit for charging and discharging.

  The DC-DC converter Uvc is a control circuit that steps down during charging to supply power to the auxiliary secondary battery block Bs and boosts during discharging to supply power to a load. The DC-DC converter Uvc makes it possible to charge and discharge secondary battery blocks having different series numbers and capacities.

  Next, the operation of the power supply system according to the first embodiment will be described. At the time of discharging, the main secondary battery block Bm is discharged to the load. At the same time, the voltage of the auxiliary secondary battery block Bs is boosted to the same voltage as the main secondary battery block Bm by the DC-DC converter and discharged to the load. The DC-DC converter (control circuit) Uvc controls the output of the DC-DC converter Uvc and the output of the main secondary battery block Bm to be the same voltage during discharging. Further, the DC-DC converter (control circuit) Uvc controls the average voltage of each secondary battery to be the same during charging.

  During discharging, the output of the auxiliary secondary battery Bs is limited while the voltage of the auxiliary secondary battery block Bs exceeds the voltage of the main secondary battery block Bm, and vice versa, the output of the auxiliary secondary battery increases. To do. That is, the average value of the voltages of the secondary batteries of the main secondary battery block Bm and the average value of the voltages of the secondary batteries of the auxiliary secondary battery block Bs are controlled to be always equal.

  Next, the configuration and operation of the DC-DC converter Uvc will be described with reference to FIG. As shown in FIG. 2, the DC-DC converter Uvc includes an inductor L1, a step-down switch S1, a step-down diode D2, a step-up switch S2, a step-up diode D1, a voltage signal comparator Cv, and a voltage signal detection. And voltage dividing resistors R1, R2, R3, R4 and the like. The voltage dividing resistors R1 and R2 constitute voltage detecting means for detecting the voltage Vm of the main secondary battery block Bm. The voltage dividing resistors R3 and R4 constitute voltage detecting means for detecting the voltage Vs of the auxiliary secondary battery block Bs.

  The DC-DC converter Uvc is a combination of a step-down converter and a step-up converter. At the time of charging, the main secondary battery block Bm is directly charged from the external DC power supply for charging, and at the same time, the voltage Vs of the auxiliary secondary battery block Bs is generated by a so-called step-down converter using the switch S1, the diode D2, and the inductor L1. The auxiliary secondary battery block Bs can be charged by reducing the pressure to the maximum. At this time, the switch S2 is turned off, a pulse signal is transmitted from the voltage signal comparator Cv, and the on / off of the switch S1 is periodically repeated. The secondary battery is charged with power from an external DC power source (which may be a solar battery or the like) connected in parallel with the load. The same applies to the following embodiments.

  On the other hand, at the time of discharging, the voltage Vs of the auxiliary secondary battery block Bs is boosted to the voltage Vm of the main secondary battery block Bm by a so-called boost converter using the switch S2, the diode D1 and the inductor L1, and the main secondary battery Output block + α. At this time, the switch S1 is turned off, a pulse signal is transmitted from the voltage signal comparator Cv, and the on / off of the switch S2 is periodically repeated.

  The voltage signal comparator Cv is a voltage signal Svm obtained by dividing the voltage Vm of the main secondary battery block Bm by the voltage dividing resistors R1 and R2, and the voltage Vs of the auxiliary secondary battery block Bs is divided by the voltage dividing resistors R3 and R4. Is compared with the voltage signal Svs obtained by voltage division. At the time of discharging, feedback control is performed so that the voltage obtained by boosting the voltage Vs of the auxiliary secondary battery block Bs and the voltage Vm of the main secondary battery block Bm become the same voltage. Thereby, the voltage balance of the main secondary battery block Bm and the auxiliary secondary battery block Bs is always maintained. Further, during charging, feedback control is performed so that the voltage obtained by stepping down the voltage Vm of the main secondary battery block Bm becomes the same voltage as the voltage Vs of the auxiliary secondary battery block Bs. Thereby, the voltage balance of the main secondary battery block Bm and the auxiliary secondary battery block Bs is always maintained.

  That is, in the voltage signal comparator Cv, the average value of the voltages of the secondary batteries constituting the main secondary battery block Bm is always equal to the average value of the voltages of the secondary batteries constituting the auxiliary secondary battery block Bs. It has the function to control.

  As shown in FIG. 3, the secondary battery balance circuit requires N (N + A) balance circuits in the main secondary battery block Bm, N in the auxiliary secondary battery block Bs, and a total of (N + A).

(Embodiment 2)
4 is a circuit diagram showing a configuration example of a power supply system according to Embodiment 2 of the present invention, FIG. 5 is a circuit diagram showing a configuration example of the DC-DC converter shown in FIG. 4, and FIG. 6 is an embodiment of the present invention. 2 is a circuit diagram showing a connection example of a secondary battery balance circuit in the power supply system according to FIG.

  First, an example of the configuration of the power supply system according to the second embodiment will be described with reference to FIG. The power supply system according to the second embodiment includes, for example, a main secondary battery block Bm, an auxiliary secondary battery block Bs, a DC-DC converter (control circuit) Uvc, and the like. The main secondary battery block Bm is configured by connecting N secondary batteries in series. Further, the auxiliary secondary battery block Bs is configured by connecting B secondary batteries in series. N and B are natural numbers and have a relationship of N> B. Moreover, the secondary battery which comprises the main secondary battery block Bm and the auxiliary secondary battery block Bs is a secondary battery which can be charged / discharged, such as a lithium ion battery, for example. Further, instead of the secondary battery, a large capacity capacitor (capacitor, capacity, etc.) such as a lithium ion capacitor may be used.

  As shown in FIG. 4, the main secondary battery block Bm and the auxiliary secondary battery block Bs are connected in series. The DC-DC converter Uvc has an X terminal on the positive electrode side of the auxiliary secondary battery block Bs, a Y terminal on the negative electrode side of the auxiliary secondary battery block Bs (the positive electrode side of the main secondary battery block Bm), and a Z terminal. Is connected to the negative electrode side of the main secondary battery block Bm. Both ends of the main secondary battery block Bm are connected to a load. The main secondary battery block Bm can also be configured by connecting in parallel a plurality of blocks each made up of N secondary batteries connected in series. In addition, the auxiliary secondary battery block Bs can be configured by connecting a plurality of blocks composed of B secondary batteries connected in series in parallel.

  Next, the configuration and operation of the DC-DC converter Uvc will be described with reference to FIG. As shown in FIG. 5, the DC-DC converter (control circuit) Uvc includes an inductor L3, an inverting boost switch S3, an inverting boost diode D4, a boost switch S4, a boost diode D3, and a voltage dividing resistor. R5, R6, R7, R8, voltage signal comparator Cv, and the like. The voltage dividing resistors R5 and R6 constitute voltage detecting means for detecting the voltage Vm of the main secondary battery block Bm. The voltage dividing resistors R7 and R8 constitute voltage detecting means for detecting the voltage Vs of the auxiliary secondary battery block Bs. The DC-DC converter Uvc in FIG. 5 is a combination of a step-up converter and a step-down converter.

  The DC-DC converter Uvc of FIG. 5 is a circuit for charging / discharging the main secondary battery block Bm that is insufficient for the target capacity and the auxiliary secondary battery block Bs for compensating for the shortage. At the time of charging, the main secondary battery block Bm is directly charged from the external DC power source, and at the same time, the voltage is boosted using the switch S4 and the diode D3 to the voltage (Vm + Vs) of the main secondary battery block Bm + auxiliary secondary battery block Bs. The voltage is boosted by the converter, and the auxiliary secondary battery block Bs can be charged. At this time, the switch S3 is turned off, a pulse signal is transmitted from the voltage signal comparator Cv, and the on / off of the switch S4 is periodically repeated. On the other hand, at the time of discharging, the voltage of the auxiliary secondary battery block Bs is inverted and boosted to the voltage of the main secondary battery block Bm by the inverting boost converter using the switch S3 and the diode D4, thereby realizing the output of the main secondary battery block + α. Let At this time, the switch S4 is turned off, a pulse signal is transmitted from the voltage signal comparator Cv, and the on / off of the switch S3 is periodically repeated.

  The voltage signal comparator Cv is a voltage signal Svm obtained by dividing the voltage Vm of the main secondary battery block Bm by the voltage dividing resistors R5 and R6, and the voltage Vs of the auxiliary secondary battery block Bs is divided by the voltage dividing resistors R7 and R8. Is compared with the voltage signal Svs obtained by voltage division. At the time of discharging, feedback control is performed so that the voltage obtained by inverting and boosting the voltage of the auxiliary secondary battery block Bs becomes the same voltage as the voltage of the main secondary battery block Bm. Thereby, the voltage balance of the main secondary battery block Bm and the auxiliary secondary battery block Bs is always maintained at the time of discharge.

  The voltage signal comparator Cv boosts the voltage of the main secondary battery block Bm to the same voltage as the sum of the voltages of the auxiliary secondary battery block Bs and the main secondary battery block Bm during charging. Feedback control. Thereby, the voltage balance of the main secondary battery block Bm and the auxiliary secondary battery block Bs is always maintained.

  As shown in FIG. 6, the secondary battery balance circuit requires N (N + B) balance circuits in the main secondary battery block Bm, N in the auxiliary secondary battery block Bs, and B in total.

(Embodiment 3)
7 is a circuit diagram showing a configuration example of a power supply system according to Embodiment 3 of the present invention, FIG. 8 is a circuit diagram showing a configuration example of the DC-DC converter shown in FIG. 7, and FIG. 9 is an embodiment of the present invention. 3 is a circuit diagram showing a connection example of a secondary battery balance circuit in the power supply system according to FIG.

  First, an example of the configuration of the power supply system according to the third embodiment will be described with reference to FIG. The power supply system according to the third embodiment includes, for example, a main secondary battery block Bm, an auxiliary secondary battery block Bs, a DC-DC converter (control circuit) Uvc, and the like. The main secondary battery block Bm is configured by connecting N secondary batteries in series. Further, the auxiliary secondary battery block Bs is configured by connecting C secondary batteries in series. N and C are natural numbers and have a relationship of N> C. Moreover, the secondary battery which comprises the main secondary battery block Bm and the auxiliary secondary battery block Bs is a secondary battery which can be charged / discharged, such as a lithium ion battery, for example. Further, instead of the secondary battery, a large capacity capacitor (capacitor, capacity, etc.) such as a lithium ion capacitor may be used.

  As shown in FIG. 7, the auxiliary secondary battery block Bs is connected in parallel with a part of the main secondary battery block Bm. Further, in the DC-DC converter Uvc, the X terminal is on the positive side of the auxiliary secondary battery block Bs (middle part of the main secondary battery block Bm), the Y terminal is on the positive side of the main secondary battery block Bm, and the Z terminal Is connected to the negative electrode side of the main secondary battery block Bm (the negative electrode side of the auxiliary secondary battery block Bs). Both ends of the main secondary battery block Bm are connected to a load. The main secondary battery block Bm can also be configured by connecting in parallel a plurality of blocks each made up of N secondary batteries connected in series. In addition, the auxiliary secondary battery block Bs can be configured by connecting a plurality of blocks composed of C secondary batteries connected in series in parallel.

  Next, the configuration and operation of the DC-DC converter Uvc will be described with reference to FIG. As shown in FIG. 8, the DC-DC converter (control circuit) Uvc includes inductors L5 and L6, a switch S5 for discharging from the auxiliary secondary battery block Bs, and a switch S6 for charging to the auxiliary secondary battery block Bs. From the diode D5 for charging the auxiliary secondary battery block Bs, the diode D6 for discharging from the auxiliary secondary battery block Bs, the capacitor C6, the voltage dividing resistors R9, R10, R11, R12, the voltage signal comparator Cv, etc. It is configured. The voltage dividing resistors R9 and R10 constitute voltage detecting means for detecting the voltage Vm of the main secondary battery block Bm. The voltage dividing resistors R11 and R12 constitute voltage detecting means for detecting the voltage Vs of the auxiliary secondary battery block Bs. The DC-DC converter Uvc in FIG. 8 is a so-called bidirectional converter.

  The DC-DC converter Uvc in FIG. 8 is a circuit that charges and discharges the main secondary battery block Bm that is insufficient for the target capacity and the auxiliary secondary battery block Bs that is used to compensate for the shortage. During charging, the main secondary battery block Bm is directly charged from the external DC power source, and at the same time, the switch S6 and the diode D5 are connected to the voltage of a part of the main secondary battery block Bm and the auxiliary secondary battery block Bs. The voltage is stepped down using the two inductors L5 and L6 and the capacitor C6, and charging to the auxiliary secondary battery block Bs and a part of the main secondary battery block Bm is enabled.

  On the other hand, at the time of discharging, the main secondary battery block Bm and the voltage of the auxiliary secondary battery block Bs are supplied to the main secondary battery block using the switch S5, the diode D6, the two inductors L5 and L6, and the capacitor C6. A voltage of Bm is realized, and an output of the main secondary battery block + α is realized.

  The voltage signal comparator Cv includes a voltage signal Svm obtained by dividing the voltage Vs of the auxiliary secondary battery block Bs from the voltage Vm of the main secondary battery block Bm by the voltage dividing resistors R9 and R10, and the auxiliary secondary battery block Cm. A voltage signal Svs obtained by dividing the voltage Vs of the next battery block Bs by the voltage dividing resistors R11 and R12 is compared. During discharging, feedback control is performed so that the voltage obtained by inverting and boosting the voltage Vs of the auxiliary secondary battery block Bs becomes the same voltage as the voltage Vm of the main secondary battery block Bm. Thereby, the voltage balance of the main secondary battery block Bm and the auxiliary secondary battery block Bs is always maintained.

  On the other hand, the voltage signal comparator Cv performs feedback control during charging so that the voltage obtained by inverting and lowering the voltage Vm of the main secondary battery block Bm becomes the same voltage as the voltage Vs of the auxiliary secondary battery block Bs. Thereby, the voltage balance of the main secondary battery block Bm and the auxiliary secondary battery block Bs is always maintained.

  As shown in FIG. 9, the balance circuit for each parallel secondary battery of the main secondary battery block Bm and the auxiliary secondary battery block Bs is only the number of series secondary batteries (N) of the main secondary battery block Bm. It's okay.

  Therefore, in the configuration of the first and second embodiments, the secondary battery balance circuit is the sum of the number of main secondary battery blocks Bm in series (N) and the number of auxiliary secondary battery blocks Bs in series (A). Although (N + A) balance circuits are required, the configuration of the third embodiment is configured such that the auxiliary secondary battery block Bs is parallel to a part of the main secondary battery block Bm, so that the number of balance circuits is increased. Can be limited to N, which is the number of main secondary battery blocks Bm in series.

(Embodiment 4)
10 is a circuit diagram showing a configuration example of a power supply system according to Embodiment 4 of the present invention, FIG. 11 is a circuit diagram showing a configuration example of the DC-DC converter shown in FIG. 10, and FIG. 12 is an embodiment of the present invention. 4 is a circuit diagram showing a connection example of a secondary battery balance circuit in the power supply system according to FIG.

  First, an example of the configuration of the power supply system according to the fourth embodiment will be described with reference to FIG. The power supply system according to the fourth embodiment includes, for example, a main secondary battery block Bm, an auxiliary secondary battery block Bs, a DC-DC converter (control circuit) Uvc, and the like. The main secondary battery block Bm is configured by connecting N secondary batteries in series. Further, the auxiliary secondary battery block Bs is configured by connecting D secondary batteries in series. N and D are natural numbers and have a relationship of N> D. Moreover, the secondary battery which comprises the main secondary battery block Bm and the auxiliary secondary battery block Bs is a secondary battery which can be charged / discharged, such as a lithium ion battery, for example. Further, instead of the secondary battery, a large capacity capacitor (capacitor, capacity, etc.) such as a lithium ion capacitor may be used.

  As shown in FIG. 10, the auxiliary secondary battery block Bs is connected in parallel with a part of the main secondary battery block Bm. In the DC-DC converter Uvc, the X terminal is on the negative side of the auxiliary secondary battery block Bs (intermediate part of the main secondary battery block Bm), and the Y terminal is on the positive side of the main secondary battery block Bm (auxiliary secondary). The Z terminal is connected to the negative electrode side of the main secondary battery block Bm on the positive electrode side of the battery block Bs. Both ends of the main secondary battery block Bm are connected to a load. The main secondary battery block Bm can also be configured by connecting in parallel a plurality of blocks each made up of N secondary batteries connected in series. In addition, the auxiliary secondary battery block Bs can be configured by connecting a plurality of blocks composed of D secondary batteries connected in series in parallel.

  Next, the configuration and operation of the DC-DC converter Uvc will be described with reference to FIG. As shown in FIG. 11, the DC-DC converter (control circuit) Uvc includes inductors L5 and L6, a switch S6 for discharging from the auxiliary secondary battery block Bs, and a switch S5 for charging to the auxiliary secondary battery block Bs. From the diode D6 for charging the auxiliary secondary battery block Bs, the diode D5 for discharging from the auxiliary secondary battery block Bs, the capacitor C6, the voltage dividing resistors R9, R10, R11, R12, the voltage signal comparator Cv, etc. It is configured. The voltage dividing resistors R11 and R12 constitute voltage detecting means for detecting the voltage Vm of the main secondary battery block Bm. The voltage dividing resistors R9 and R10 constitute voltage detecting means for detecting the voltage Vs of the auxiliary secondary battery block Bs. The DC-DC converter Uvc in FIG. 11 is a so-called bidirectional converter.

  The DC-DC converter Uvc of FIG. 11 is a circuit that charges and discharges the main secondary battery block Bm that is insufficient for the target capacity and the auxiliary secondary battery block Bs that is used to compensate for the shortage. At the time of charging, the switch S5 and the diode D6 are directly charged from the external DC power source to the main secondary battery block Bm, and at the same time up to a part of the main secondary battery block Bm and the voltage of the auxiliary secondary battery block Bs. The voltage is stepped down using the two inductors L5 and L6 to allow charging to the auxiliary secondary battery block Bs and a part of the main secondary battery block Bm.

  On the other hand, at the time of discharging, the voltage of the main secondary battery block Bm and the voltage of the auxiliary secondary battery block Bs are converted to the voltage of the main secondary battery block Bm using the switch S6, the diode D5, and the two inductors L5 and L6. To realize the output of the main secondary battery block + α.

  The voltage signal comparator Cv includes a voltage signal Svm obtained by dividing the voltage Vs of the auxiliary secondary battery block Bs from the voltage Vm of the main secondary battery block Bm by the voltage dividing resistors R11 and R12, and the auxiliary secondary battery block Bm. A voltage signal Svs obtained by dividing the voltage Vs of the next battery block Bs by the voltage dividing resistors R9 and R10 is compared. During discharging, feedback control is performed so that the voltage obtained by inverting and boosting the voltage Vs of the auxiliary secondary battery block Bs becomes the same voltage as the voltage Vm of the main secondary battery block Bm. Thereby, the voltage balance of the main secondary battery block Bm and the auxiliary secondary battery block Bs is always maintained.

  On the other hand, the voltage signal comparator Cv performs feedback control during charging so that the voltage obtained by inverting and lowering the voltage Vm of the main secondary battery block Bm becomes the same voltage as the voltage Vs of the auxiliary secondary battery block Bs. Thereby, the voltage balance of the main secondary battery block Bm and the auxiliary secondary battery block Bs is always maintained.

  As shown in FIG. 12, the balance circuit for each parallel secondary battery of the main secondary battery block Bm and the auxiliary secondary battery block Bs is only the number of secondary batteries in series (N) in the main secondary battery block Bm. It's okay.

  Therefore, in the configuration of the first and second embodiments, the secondary battery balance circuit is the sum of the number of main secondary battery blocks Bm in series (N) and the number of auxiliary secondary battery blocks Bs in series (A). Although (N + A) balance circuits are required, the configuration of the fourth embodiment is configured such that the auxiliary secondary battery block Bs is parallel to a part of the main secondary battery block Bm, so that the number of balance circuits is increased. Can be limited to N, which is the number of main secondary battery blocks Bm in series.

(Effects of Embodiments 1 to 4)
FIG. 13 is a diagram showing charging characteristics of the power supply system according to Embodiment 1 of the present invention. FIG. 13 is a diagram illustrating a charging characteristic when a lithium ion battery having a main secondary battery block Bm capacity of 2.92 Ah and an auxiliary secondary battery block Bs capacity of 2.42 Ah is actually CVCC charged. . It is confirmed that the average value (a) of the secondary battery voltage of the main secondary battery block Bm and the average value (b) of the secondary battery voltage of the auxiliary secondary battery block Bs are always equal throughout the entire charging period. It is shown.

  In FIG. 13, (a) is the average value of the secondary battery voltage of the main secondary battery block, (b) is the average value of the secondary battery voltage of the auxiliary secondary battery block, and (c) is the main secondary battery. The charging current of the block, (d) shows the charging current of the auxiliary secondary battery block, and (e) shows the charging current.

  FIG. 14 is a diagram showing discharge characteristics of the power supply system according to Embodiment 1 of the present invention. FIG. 14 is a diagram showing discharge characteristics when CC discharge is performed on a lithium ion battery in which the capacity of the main secondary battery block Bm is 2.92 Ah and the capacity of the auxiliary secondary battery block Bs is 2.42 Ah. In all periods, the average value (f) of the secondary battery voltage of the main secondary battery block Bm and the average value (g) of the cell voltage of the auxiliary secondary battery block Bs are actually equal.

  When the average value (g) of the secondary battery voltage of the auxiliary secondary battery block Bs is lower than the average value (f) of the secondary battery voltage of the main secondary battery block Bm, the auxiliary secondary battery block It is controlled so as to suppress the output of Bs. Actually, when the auxiliary secondary battery block Bs approaches the end of discharge first due to the difference in capacity, the current value (i) decreases, and accordingly, the average voltage (g) of the auxiliary secondary battery block Bs. However, the auxiliary secondary battery block Bs is controlled in a direction to suppress the output, and as a result, indicates that the same voltage is being maintained.

  In FIG. 14, (f) is the average value of the secondary battery voltage of the main secondary battery block, (g) is the average value of the secondary battery voltage of the auxiliary secondary battery block, and (h) is the main secondary battery. The output current of the block, (i) indicates the output current of the auxiliary secondary battery block, and (k) indicates the output current.

As a result, the power supply system according to the first embodiment of the present invention has a discharge capacity of about 3.5 Ah, and the auxiliary secondary battery block Bs indicates that the discharge capacity is larger than the capacity of the main secondary battery block. Show.
The description of the characteristics of the power supply system according to the second to fourth embodiments is omitted, but the same effect can be obtained.

  Therefore, according to the power supply systems of Embodiments 1 to 4 of the present invention, since a flexible battery capacity can be realized, an inexpensive and lightweight power supply system can be provided because there is no surplus capacity. .

  Moreover, according to the power supply system of Embodiment 1-4 of this invention, it can control to always maintain the voltage balance of the main secondary battery block Bm and the auxiliary battery block Bs.

  In addition, according to the power supply systems of Embodiments 3 and 4 of the present invention, the number of secondary battery balance circuits can be reduced to only N in series with the main secondary battery block Bm, and further circuit weight reduction can be achieved. Lower prices are possible.

  Although the invention made by the present inventor has been specifically described based on the embodiment, the invention is not limited to the embodiment and can be variously modified without departing from the scope of the invention. Needless to say.

  For example, the main secondary battery block Bm and the auxiliary secondary battery block Bs can be replaced with large-capacity capacitors. In this case, the switching time ratio can be controlled to be fixed (controlled with a fixed duty) without using the voltage signal comparator.

It is a circuit diagram which shows the structural example of the power supply system by Embodiment 1 of this invention. It is a circuit diagram which shows the structural example of the DC-DC converter shown in FIG. It is a circuit diagram which shows the example of a connection of a secondary battery balance circuit in the power supply system by Embodiment 1 of this invention. It is a circuit diagram which shows the structural example of the power supply system by Embodiment 2 of this invention. FIG. 5 is a circuit diagram illustrating a configuration example of the DC-DC converter illustrated in FIG. 4. In the power supply system by Embodiment 2 of this invention, it is a circuit diagram which shows the example of a connection of a secondary battery balance circuit. It is a circuit diagram which shows the structural example of the power supply system by Embodiment 3 of this invention. It is a circuit diagram which shows the structural example of the DC-DC converter shown in FIG. In the power supply system by Embodiment 3 of this invention, it is a circuit diagram which shows the example of a connection of a secondary battery balance circuit. It is a circuit diagram which shows the structural example of the power supply system by Embodiment 4 of this invention. It is a circuit diagram which shows the structural example of the DC-DC converter shown in FIG. In the power supply system by Embodiment 4 of this invention, it is a circuit diagram which shows the example of a connection of a secondary battery balance circuit. It is a figure which shows the charge characteristic of the power supply system by Embodiment 1 of this invention. It is a figure which shows the discharge characteristic of the power supply system by Embodiment 1 of this invention. It is a circuit diagram which shows the structural example of the power supply system examined as a premise of this invention. It is a circuit diagram which shows the structural example of the power supply system examined as a premise of this invention. It is a circuit diagram which shows the structural example of the power supply system examined as a premise of this invention. It is a circuit diagram which shows the structural example of the power supply system examined as a premise of this invention.

Explanation of symbols

Bm Main secondary battery block Bs Auxiliary secondary battery block Uvc DC-DC converter (control circuit)
L1 to L6 Inductor S1 to S6 Switch D1 to D6 Diode Cv Voltage signal comparator R1 to R12 Voltage dividing resistor C6 Capacitor

Claims (17)

A first secondary battery block including a first secondary battery row in which N secondary batteries are connected in series;
A second secondary battery block including a second secondary battery array in which A secondary batteries fewer than N are connected in series;
A control circuit that performs voltage conversion between the first secondary battery block and the second secondary battery block;
A power supply system, wherein both poles of the first secondary battery block are connected to a load. The control circuit includes:
At the time of charging, the voltage of the first secondary battery block is stepped down to supply power to the second secondary battery block,
2. The power supply system according to claim 1, wherein during discharging, the voltage of the second secondary battery block is boosted to supply power to the load.   The power supply system according to claim 1 or 2, wherein the first secondary battery block and the second secondary battery block are connected in parallel via the control circuit. The first secondary battery block further includes a third secondary battery row in which N secondary batteries are connected in series,
The power supply system according to any one of claims 1 to 3, wherein the third secondary battery row is connected in parallel to the first secondary battery row. The second secondary battery block further includes a fourth secondary battery row in which A secondary batteries are connected in series,
5. The power supply system according to claim 1, wherein the fourth secondary battery row is connected in parallel to the second secondary battery row. 6.   The control circuit includes an inductor, a first step-down switch, a first step-down diode, a second step-up switch, and a second step-up diode. The power supply system according to any one of claims 1 to 5. The control circuit includes:
First voltage detection means for detecting a voltage of the first secondary battery block and outputting a first detection signal;
Second voltage detection means for detecting a voltage of the second secondary battery block and outputting a second detection signal;
A comparator for comparing the first detection signal and the second detection signal;
The power supply system according to claim 6, wherein the step-down and step-up are adjusted by an output of the comparator.   The power supply system according to claim 1, wherein the first secondary battery block and the second secondary battery block are connected in series.   The control circuit includes an inductor, a first switch for inverting boost, a first diode for inverting boost, a second switch for boost, and a second diode for boost. The power supply system according to claim 8. The control circuit includes:
First voltage detection means for detecting a voltage of the first secondary battery block and outputting a first detection signal;
Second voltage detection means for detecting a voltage of the second secondary battery block and outputting a second detection signal;
A comparator for comparing the first detection signal and the second detection signal;
At the time of discharging, feedback control is performed so that the voltage of the second secondary battery block is inverted and boosted to the same voltage as the voltage of the first secondary battery block by the output of the comparator. The power supply system according to claim 9. The control circuit includes:
First voltage detection means for detecting a voltage of the first secondary battery block and outputting a first detection signal;
Second voltage detection means for detecting a voltage of the second secondary battery block and outputting a second detection signal;
A comparator for comparing the first detection signal and the second detection signal;
At the time of charging, the voltage of the first secondary battery block is set to the same voltage as the sum of the voltages of the second secondary battery block and the first secondary battery block by the output of the comparator. The power supply system according to claim 9, wherein feedback control is performed so as to boost the voltage.   The power supply system according to claim 1, wherein the second secondary battery block is connected in parallel to a part of the first secondary battery block.   The control circuit is a bidirectional converter, a first switch for discharging, a second switch for charging, a first diode for discharging, a second diode for charging, a capacitor, The power supply system according to claim 12, further comprising first and second inductors. The control circuit includes:
First voltage detection means for detecting a voltage of the first secondary battery block and outputting a first detection signal;
Second voltage detection means for detecting a voltage of the second secondary battery block and outputting a second detection signal;
A comparator for comparing the first detection signal and the second detection signal;
At the time of discharging, feedback control is performed so that the voltage of the second secondary battery block is inverted and boosted to the same voltage as the voltage of the first secondary battery block by the output of the comparator. The power supply system according to claim 13. The control circuit includes:
First voltage detection means for detecting a voltage of the first secondary battery block and outputting a first detection signal;
Second voltage detection means for detecting a voltage of the second secondary battery block and outputting a second detection signal;
A comparator for comparing the first detection signal and the second detection signal;
The feedback control is performed so that the voltage of the first secondary battery block is inverted and stepped down to the same voltage as that of the second secondary battery block by the output of the comparator during charging. The power supply system according to 13 or 14.   The power supply system according to any one of claims 12 to 15, further comprising N balance circuits connected in parallel to each of the secondary batteries of the first secondary battery block. The power supply system according to any one of claims 1 to 16,
A power supply system, wherein the secondary battery is replaced with a large capacity capacitor.

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