JP6110199B2 - Storage element monitoring circuit, charging system, and integrated circuit - Google Patents

Description

  The present invention relates to a storage element monitoring circuit, a charging system, and an integrated circuit.

  Generally, a lithium-ion battery or the like, which is an assembled battery in which a plurality of battery cells (storage elements) are connected in series, is used as a large-capacity and high-power battery used for driving a motor of a hybrid vehicle or an electric vehicle. . There is also a monitoring circuit for monitoring and controlling the battery cell voltage. For example, it is known to avoid overcharging by passing a current through a shunt circuit when the cell voltage exceeds a reference voltage (see, for example, Patent Documents 1 and 2).

JP2012-147487A JP 2012-228002 A

  When a plurality of battery cells are modularized, a complicated system construction is required to check whether the monitoring function of the monitoring circuit is operating normally. For example, it is necessary to perform complicated processing for each battery cell, such as detecting that a shunt current flows, storing the detection flag in a register, reading the detection flag from the register, and checking via serial communication. It becomes.

  An object of the present invention is to provide a storage element monitoring circuit, a charging system, and an integrated circuit capable of checking whether a monitoring function is operating normally by a simple method.

According to one aspect of the present invention, a plurality of shunt circuits having transistors connected in parallel to a plurality of power storage elements, a plurality of on / off detection circuits for detecting on / off of each of the plurality of shunt circuits, Based on output signals of the plurality of on / off detection circuits, cell voltages supplied to the plurality of power storage elements have exceeded a predetermined voltage value, and transistors included in the plurality of shunt circuits are operating normally. There is provided a storage element monitoring circuit including a check circuit for checking the above and outputting a check result .

According to another aspect of the present invention, a charging unit that generates a charging current, a plurality of power storage elements connected in series to the charging unit, and each of the plurality of power storage elements are monitored, and the monitoring function is A storage element monitoring circuit that checks whether or not it is operating normally; and a control circuit that monitors an output signal of the storage element monitoring circuit, wherein the storage element monitoring circuit is connected in parallel to each of the plurality of storage elements. A plurality of shunt circuits having transistors, a plurality of on / off detection circuits for detecting on / off of each of the plurality of shunt circuits, and the plurality of power storages based on output signals of the plurality of on / off detection circuits. Check that the cell voltage supplied to the element exceeds a predetermined voltage value and that the transistors of the plurality of shunt circuits are operating normally , The charging system and a check circuit for outputting a check result is provided.

  According to another aspect of the present invention, there is provided an integrated circuit including any one of the above storage element monitoring circuits.

  ADVANTAGE OF THE INVENTION According to this invention, the electrical storage element monitoring circuit, charging system, and integrated circuit which can check whether the monitoring function is operate | moving normally by a simple method can be provided.

The typical block block diagram of the charging system which concerns on embodiment. The typical block block diagram of the electrical storage element monitoring circuit which concerns on embodiment. FIG. 3 is a schematic block configuration diagram of a cell voltage detection circuit shown in FIG. 2. FIG. 3 is an explanatory diagram of the on / off detection circuit shown in FIG. 2, wherein (a) a schematic block configuration diagram and (b) a graph showing hysteresis characteristics. FIG. 3 is another schematic block configuration diagram of the on / off detection circuit shown in FIG. 2. FIG. 6 is still another schematic block configuration diagram of the on / off detection circuit shown in FIG. 2. It is a graph which shows typically the example of a waveform in the charging system concerning an embodiment, (a) The example of a waveform of charging current, (b) The example of the waveform of charging voltage and cell voltage, (c) The output of a cell voltage detection circuit (D) waveform example of output signal of on / off detection circuit, (e) waveform example of output signal of cell voltage detection circuit, (f) waveform example of output signal of on / off detection circuit, g) Waveform example of output signal of check circuit. 5 is a graph schematically showing another waveform example in the charging system according to the embodiment, where (a) a waveform example of a charging current, (b) a waveform example of a charging voltage and a cell voltage, and (c) a cell voltage detection circuit. (D) Waveform example of output signal of on / off detection circuit, (e) Waveform example of output signal of cell voltage detection circuit, (f) Waveform example of output signal of on / off detection circuit (G) Waveform example of output signal of check circuit. Explanatory drawing of the integrated circuit carrying the electrical storage element monitoring circuit which concerns on embodiment. Explanatory drawing of another integrated circuit carrying the electrical storage element monitoring circuit which concerns on embodiment. Explanatory drawing of another integrated circuit carrying the electrical storage element monitoring circuit which concerns on embodiment. Explanatory drawing of the modification at the time of modularizing the electrical storage element monitoring circuit which concerns on embodiment. The typical plane pattern block diagram which illustrates the basic structure of the EDLC internal electrode as an electrical storage element with which the electrical storage element monitoring circuit which concerns on embodiment is provided. The typical plane pattern block diagram which illustrates the basic structure of the lithium ion capacitor internal electrode as an electrical storage element with which the electrical storage element monitoring circuit which concerns on embodiment is provided. The typical plane pattern block diagram which illustrates the basic structure of the lithium ion battery internal electrode as an electrical storage element with which the electrical storage element monitoring circuit which concerns on embodiment is provided.

  Next, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness of each component and the planar dimensions is different from the actual one. Therefore, specific thicknesses and dimensions should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  Further, the embodiments described below exemplify apparatuses and methods for embodying the technical idea of the present invention, and the embodiments of the present invention include the material, shape, and structure of each component. The arrangement is not specified below. Various modifications can be made to the embodiment of the present invention within the scope of the claims.

[Embodiment]
Hereinafter, embodiments will be described in detail with reference to FIGS.

(Charging system)
As shown in FIG. 1, the schematic block configuration of the charging system according to the embodiment includes a charging unit 10 that generates a charging current I _chg and a plurality of power storage elements C ₁ and C ₂ connected in series to the charging unit 10. , C ₃ ,..., C _n-2 , C _n-1 , C _n and a plurality of storage elements C ₁ , C ₂ , C ₃ ,..., C _n-2 , C _n-1 , C _n In addition, a storage element monitoring circuit 20 that checks whether the monitoring function is operating normally and a microcomputer (control circuit) 30 that monitors the output signal F of the storage element monitoring circuit 20 are provided. The storage elements C ₁ , C ₂ , C ₃ ,..., C _n-2 , C _n-1 , C _n are, for example, lithium ion battery cells, electric double layer capacitor cells, lithium ion capacitor cells, SCiB (registered trademark). Cell etc.

Here, a plurality of power storage elements C ₁ , C ₂ , C ₃ ,..., C _n−2 , C _n−1 , C _n and the power storage element monitoring circuit 20 are modularized to form a module M1. As a final check of the module M1, a simple and accurate check method is desired when checking whether the monitoring function of the storage element monitoring circuit 20 is operating normally. The monitoring function here is a function that monitors (detects), for example, overcharge, overdischarge, overcurrent, and the like.

(Storage element monitoring circuit)
The schematic block configuration of a storage element monitoring circuit 20 according to the embodiment, as shown in FIG. 2, a plurality of power storage devices C _1, ..., a plurality of shunt circuits connected in parallel with each C _n S _A, ..., S _Z , a plurality of shunt circuits S _A ,..., S _Z , a plurality of on / off detection circuits 24 _A ,..., 24 _Z and a plurality of on / off detection circuits 24 _A ,. comprises 24 _Z plurality of shunt circuits S _a based on the output signal of, ..., and a check circuit 25 for checking whether S _Z is operating normally.

Specifically, check circuit 25, a plurality of on / off detection circuit 24 _A, ..., an AND circuit for all the output signals are input 24 _Z. Such an AND circuit outputs a flag signal indicating that all of the plurality of shunt circuits S _A ,..., S _Z are operating normally.

Alternatively, check circuit 25, a plurality of on / off detection circuit 24 _A, ..., may be OR circuit all the output signals are input 24 _Z. Such an OR circuit outputs a flag signal indicating that the operation of the shunt circuits S _A ,..., S _Z has started.

(Shunt circuit)
Shunt circuit shown in FIG. 2 S _A, a transistor 23 _A when the transistor 23 _A is connected in parallel to the power storage device C _1, the cell voltage V _A supplied to the power storage device C ₁ exceeds the reference voltage V _ref and a cell voltage detection circuit 21 _a to turn on. When checking whether the monitoring function is operating normally, the cell voltages V _A ,..., V _Z supplied to the plurality of power storage elements C ₁ ,..., C _n all exceed the reference voltage V _ref. In addition, the plurality of power storage elements C ₁ ,..., C _n are charged (described later). The drain of the transistor 23 _A is connected to the positive terminal of the storage element C ₁ via the shunt resistor 22 _A , the source is connected to the negative terminal of the storage element C ₁ , and the gate is connected to the output terminal of the cell voltage detection circuit 21 _A. Is done. When the transistor 23 _A is turned on, a surplus shunt current from the charging current I _chg can be shunted to the shunt circuit S _A. Thereby, it is possible to suppress the battery current flowing through the storage element C ₁ and suppress the increase in the cell voltage V _A. Here, the description is focused on the shunt circuit S _A , but the same applies to the other shunt circuits S _B ,..., S _Z.

_A schematic block configuration of the cell voltage detection circuit 21A shown in FIG. 2 is expressed as shown in FIG. As shown in FIG. 3, the cell voltage detection circuit 21 _A includes a comparator 21 _A1 connected in parallel to the power storage element C ₁ . Positive input terminal of the comparator 21 _A1 is connected to the positive terminal of the storage element C _1, the negative input terminal of the comparator 21 _A1 is connected to the negative terminal of the storage element C ₁ via the reference voltage generating unit 21 _A2, the comparator 21 _A1 the output terminal is connected to the transistor 23 _a. Reference voltage generation unit 21 _A2 generates reference voltage V _ref that is determined based on the withstand voltage of power storage element C ₁ . Here, although the description focuses on the cell voltage detection circuit 21 _A, other cell voltage detection circuit 21 _B, ..., is the same for 21 _Z.

(On / off detection circuit)
_A schematic block configuration of the on / off detection circuit 24A shown in FIG. 2 is expressed as shown in FIG. As shown in FIG. 4 (a), on / off detection circuit 24 _A is provided with a Schmitt trigger circuit 24 _A1 connected in parallel to the power storage device C _1. The input terminal of the Schmitt trigger circuit 24 _A1 is connected between the shunt resistor 22 _A and the transistor 23 _A, and the output terminal of the Schmitt trigger circuit 24 _A1 is connected to the input terminal of the check circuit 25. The Schmitt trigger circuit 24 _A1 has hysteresis as shown in FIG. That is, when the input voltage V _i increases to V _t2 , the output voltage V _o changes from V _L to V _H. Conversely, when the input voltage V _i decreases to V _t1 , the output voltage V _o changes from V _H to V _L. According to such a Schmitt trigger circuit 24 _A1 , since a stable output can be obtained, it is possible to perform processing with high accuracy in a subsequent circuit. Here, although the description focuses on / off detection circuit 24 _A, other on / off detection circuit 24 _B, ..., is the same for 24 _Z.

Another schematic block configuration of the on / off detection circuit 24 _A shown in FIG. 2 is expressed as shown in FIG. As shown in FIG. 5, ON / OFF detecting circuit 24 _A may be provided with a comparator 24 _A2 connected in parallel to the power storage device C _1. Positive input terminal of the comparator 24 _A2 is the shunt resistor 22 _A - is connected between the transistors 23 _A, the negative input terminal of the comparator 24 _A2 is connected to the reference voltage generating unit (not shown), an output terminal of the comparator 24 _A2 is the check circuit 25 Connected to input terminal. Here, although the description focuses on / off detection circuit 24 _A, other on / off detection circuit 24 _B, ..., is the same for 24 _Z.

Yet another schematic block diagram of the on / off detection circuit 24 _A shown in FIG. 2 is expressed as shown in FIG. As shown in FIG. 6, the on / off detection circuit 24 _A may include a Schmitt trigger circuit 24 _A5 via a MOS transistor 24 _A3 . The input terminal of the Schmitt trigger circuit 24 _A5 is connected between the MOS transistor 24 _A3 and the resistor 24 _A4, and the output terminal of the Schmitt trigger circuit 24 _A5 is connected to the input terminal of the check circuit 25. The point that the Schmitt trigger circuit 24 _A5 has hysteresis is the same as that of the Schmitt trigger circuit 24 _A1 shown in FIG. Here, although the description focuses on / off detection circuit 24 _A, other on / off detection circuit 24 _B, ..., is the same for 24 _Z.

(Waveform example 1)
A graph schematically showing a waveform example in the charging system according to the embodiment is expressed as shown in FIG. Here, a case where all of the plurality of shunt circuits S _A ,..., S _Z are operating normally will be described.

First, as shown in FIG. 7A, when the charging current I _chg is supplied from the charging unit 10, the charging voltage V ₁ rises as shown in FIG. _1, ..., cell voltage V _a supplied to C _n, ..., V _Z is also increased. Accordingly, when the cell voltage V _A exceeds the reference voltage V _ref , the output signal V _A1 of the cell voltage detection circuit 21 _A becomes high as shown in FIG. 7C. Thereby, when the transistor 23 _A is turned on, the output signal V _A2 of the on / off detection circuit 24 _A becomes high as shown in FIG. 7D. In this way, as shown in FIG. 7 (e), all the cell voltage detection circuit 21 _A, ..., 21 _Z of the output signal V _A1, ..., V _Z1 goes high, shown in FIG. 7 (f) as such, all on / off detection circuit 24 _a, ..., 24 _Z of the output signal V _A2, ..., V _Z2 becomes high. As a result, as shown in FIG. 7G, the output signal F of the check circuit 25 becomes high and a flag signal is output. Thereby, in the microcomputer 30, it can be confirmed that all of the plurality of shunt circuits S _A ,..., S _Z are operating normally.

(Waveform example 2)
A graph schematically showing another waveform example in the charging system according to the embodiment is expressed as shown in FIG. Here, a plurality of shunt circuits S _A, ..., among the S _Z, will be described only shunt circuit S _Z is not working properly.

Since FIGS. 8A to 8E are the same as FIGS. 7A to 7E, detailed description thereof is omitted. When the shunt circuit S _Z is not operating normally, as shown in FIG. 8E, even if the output signal V _Z1 of the cell voltage detection circuit 21 _Z becomes high, as shown in FIG. In addition, the output signal V _Z2 of the on / off detection circuit 24 _Z remains low. The case where the shunt circuit S _Z is not operating normally is a case where the transistor 23 _Z is not turned on for some reason. As a result, as shown in FIG. 8G, the output signal F of the check circuit 25 also remains low. Thereby, in the microcomputer 30, it can be confirmed that any of the plurality of shunt circuits S _A ,..., S _Z is not operating normally.

As described above, in the embodiment, the power storage device C ₁ of all the channels, ..., cell voltage V _A supplied to C _n, ..., as V _Z exceeds the reference voltage V _ref, the module M1 from outside Charge. Then, the microcomputer 30 monitors the output signal F of the storage element monitoring circuit 20 to check whether the monitoring function is operating normally. In this way, the cell voltage V _A, ..., V _Z the detected transistor 23 from _A, ..., 23 _Z can be checked series of operations simple and accurately health until ON. As a result, the circuit configuration of the storage element monitoring circuit 20 is simplified as compared with the conventional case, and the cost can be reduced.

Here, the description is made on the assumption that the check circuit 25 is an AND circuit, but the check circuit 25 is not limited to this. For example, when using an OR circuit as a check circuit 25, a plurality of shunt circuits S _A, ..., if any of the S _Z is operating normally, the output signal F of the check circuit 25 becomes high . In this case, the microcomputer 30 can detect that the cell balance is turned on.

(Specific example of LSI)
An integrated circuit L1 on which the storage element monitoring circuit 20 according to the embodiment is mounted is expressed as shown in FIG. As shown in FIG. 9, the integrated circuit L1 is shunt circuit S _A, ..., and S _Z, on / off detection circuit 24 _A, ..., may be mounted and 24 _Z, and a check circuit 25.

Another integrated circuit L2 on which the storage element monitoring circuit 20 according to the embodiment is mounted is expressed as shown in FIG. Here, a case where the shunt resistors 22 _A ,..., 24 _Z are not mounted on the integrated circuit L2 is illustrated. The on / off detection circuits 24 _A ,..., 24 _Z and the check circuit 25 are mounted on the integrated circuit L2 as in FIG.

Still another integrated circuit L3 equipped with the storage element monitoring circuit 20 according to the embodiment is expressed as shown in FIG. Here, the shunt resistor 22 _A, ..., 24 _Z and the transistor 23 _A, ..., illustrates a case that does not include the 23 _Z to the integrated circuit L3. The on / off detection circuits 24 _A ,..., 24 _Z and the check circuit 25 are mounted on the integrated circuit L3 as in FIG.

(Modification of module)
In FIG. 1, a plurality of power storage elements C ₁ , C ₂ , C ₃ ,..., C _n-2 , C _n−1 , C _n and the power storage element monitoring circuit 20 are modularized. It is not limited to this. For example, as shown in FIG. 12, a module M2 is formed by modularizing a range excluding a plurality of power storage elements C ₁ , C ₂ , C ₃ ,..., C _n−2 , C _n−1 , C _n. Also good.

(EDLC internal electrode)
As the storage elements C ₁ ,..., C _{n included in the} storage element monitoring circuit 20 according to the embodiment, an electric double layer capacitor (EDLC) cell can be used, and the basic structure of the EDLC internal electrode is shown in FIG. It is expressed as shown in As shown in FIG. 13, in the EDLC internal electrode, at least one layer of active material electrodes 41 and 42 is provided with a separator 40 through which only an electrolytic solution and ions pass, and extraction electrodes 43 and 44 are active material electrodes 41 and 42. The extraction electrodes 43 and 44 are connected to the power supply voltage. The lead electrodes 43 and 44 are made of, for example, aluminum foil, and the active material electrodes 41 and 42 are made of, for example, activated carbon. The separator 40 is larger than the active material electrodes 41 and 42 (having a large area) so as to cover the entire active material electrodes 41 and 42. The separator 40 does not depend on the type of energy device in principle, but heat resistance is required particularly when reflow treatment is required. When heat resistance is not required, polypropylene or the like can be used, and when heat resistance is required, a cellulosic material can be used. The EDLC internal electrode is impregnated with the electrolytic solution, and the electrolytic solution and ions move through the separator 40 during charging and discharging.

(Lithium ion capacitor internal electrode)
As the storage elements C ₁ ,..., C _{n included in the} storage element monitoring circuit 20 according to the embodiment, a lithium ion capacitor cell can be used, and the basic structure of the internal electrode of the lithium ion capacitor is shown in FIG. It is expressed as follows. As shown in FIG. 14, in the lithium ion capacitor internal electrode, at least one layer of active material electrodes 45 and 42 is interposed with a separator 40 through which only an electrolyte and ions pass, and extraction electrodes 43 and 44 are active material electrodes 45. , 42, and the lead electrodes 43, 44 are connected to a power supply voltage. The active material electrode 42 on the positive electrode side is made of, for example, activated carbon, and the active material electrode 45 on the negative electrode side is made of, for example, Li-doped carbon. The lead electrode 44 on the positive electrode side is made of, for example, aluminum foil, and the lead electrode 43 on the negative electrode side is made of, for example, copper foil. The separator 40 is larger than the active material electrodes 45 and 42 (having a large area) so as to cover the entire active material electrodes 45 and 42. The lithium ion capacitor internal electrode is impregnated with the electrolytic solution, and the electrolytic solution and ions move through the separator 40 during charging and discharging.

(Lithium ion battery internal electrode)
As the storage elements C ₁ ,..., C _{n included in the} storage element monitoring circuit 20 according to the embodiment, a lithium ion battery cell can be used, and the basic structure of the lithium ion battery internal electrode is shown in FIG. It is expressed as follows. As shown in FIG. 15, in the lithium ion battery internal electrode, at least one layer of the active material electrodes 45, 46 interposes the separator 40 through which only the electrolyte and ions pass, and the extraction electrodes 43, 44 are the active material electrodes 45. , 46, and the extraction electrodes 43, 44 are connected to the power supply voltage. The active material electrode 46 on the positive electrode side is made of, for example, LiCoO _2, and the active material electrode 45 on the negative electrode side is made of, for example, Li-doped carbon. The lead electrode 44 on the positive electrode side is made of, for example, aluminum foil, and the lead electrode 43 on the negative electrode side is made of, for example, copper foil. The separator 40 is larger than the active material electrodes 45 and 46 (having a large area) so as to cover the entire active material electrodes 45 and 46. The lithium ion battery internal electrode is impregnated with an electrolytic solution, and the electrolytic solution and ions move through the separator 40 during charging and discharging.

  As described above, according to the present invention, it is possible to provide a storage element monitoring circuit, a charging system, and an integrated circuit that can check whether the monitoring function is operating normally by a simple method. .

[Other embodiments]
As described above, the present invention has been described according to the embodiment. However, it should be understood that the descriptions and drawings constituting a part of this disclosure are illustrative and do not limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

As described above, the present invention includes various embodiments not described herein. For example, the storage element monitoring circuit 20 includes a plurality of storage elements C _1, ..., it is sufficient that a function of monitoring the C _n, the shunt circuit S _A, ..., whether equipped with S _Z is particularly limited It is not a thing.

  The storage element monitoring circuit, the charging system, and the integrated circuit according to the present invention can be used for various devices that need to monitor the storage element, such as PCs, automobiles, industrial equipment, motorcycles, buses, and trains. Moreover, as an electrical storage element, a lithium ion battery cell, an electric double layer capacitor cell, a lithium ion capacitor cell, an SCiB cell, etc. can be used.

10 charging unit 20 storage element monitoring circuit 21 _A, ..., 21 _Z cell voltage detection circuit 23 _A, ..., 23 _Z transistor 24 _A, ..., 24 _Z ON / OFF detecting circuit 24 _A1, ..., 24 _Z1 Schmitt trigger circuit 25 Check circuit (AND circuit, OR circuit)
30 Control circuit (microcomputer)
C ₁ , ..., C _n storage elements S _A , ..., S _Z shunt circuit V _A , ..., V _Z cell voltage V _ref reference voltages L1, L2, L3 integrated circuit

Claims (19)

A plurality of shunt circuits having transistors connected in parallel to the plurality of power storage elements;
A plurality of on / off detection circuits for detecting on / off of each of the plurality of shunt circuits;
Based on output signals of the plurality of on / off detection circuits, cell voltages supplied to the plurality of power storage elements have exceeded a predetermined voltage value, and transistors included in the plurality of shunt circuits are operating normally. And a check circuit that outputs a check result.   The storage element monitoring circuit according to claim 1, wherein the check circuit is an AND circuit to which all output signals of the plurality of on / off detection circuits are input.   The storage element monitoring circuit according to claim 2, wherein the check circuit outputs a flag signal indicating that all of the plurality of shunt circuits are operating normally.   The storage element monitoring circuit according to claim 1, wherein the check circuit is an OR circuit to which all output signals of the plurality of on / off detection circuits are input.   The storage element monitoring circuit according to claim 4, wherein the check circuit outputs a flag signal indicating that the operation of the shunt circuit has started. The shunt circuit includes the transistor and a cell voltage detection circuit that turns on the transistor when a cell voltage supplied to the storage element exceeds a reference voltage,
The power storage device according to claim 1, wherein the plurality of power storage devices are charged such that all cell voltages supplied to the plurality of power storage devices exceed the reference voltage. Element monitoring circuit.   The storage element monitoring circuit according to claim 1, wherein the on / off detection circuit includes a Schmitt trigger circuit having hysteresis.   The storage element monitoring circuit according to claim 1, wherein the storage element is any one of a lithium ion battery cell, an electric double layer capacitor cell, a lithium ion capacitor cell, and an SCiB cell. . The storage element monitoring circuit according to claim 6 , wherein a common reference voltage is supplied from a reference voltage generation unit to both the on / off detection circuit and the cell voltage detection circuit. A charging unit for generating a charging current;
A plurality of power storage elements connected in series to the charging unit;
A storage element monitoring circuit that monitors each of the plurality of storage elements and checks whether the monitoring function is operating normally;
A control circuit for monitoring the output signal of the storage element monitoring circuit,
The storage element monitoring circuit includes:
A plurality of shunt circuits having transistors connected in parallel to each of the plurality of power storage elements;
A plurality of on / off detection circuits for detecting on / off of each of the plurality of shunt circuits;
Based on output signals of the plurality of on / off detection circuits, cell voltages supplied to the plurality of power storage elements have exceeded a predetermined voltage value, and transistors included in the plurality of shunt circuits are operating normally. And a check circuit for checking the result and outputting a check result.   The charging system according to claim 10, wherein the check circuit is an AND circuit to which all output signals of the plurality of on / off detection circuits are input.   The charging system according to claim 11, wherein the check circuit outputs a flag signal indicating that all of the plurality of shunt circuits are operating normally.   The charging system according to claim 10, wherein the check circuit is an OR circuit to which all output signals of the plurality of on / off detection circuits are input.   The charging system according to claim 13, wherein the check circuit outputs a flag signal indicating that the operation of the shunt circuit has started. The shunt circuit includes the transistor and a cell voltage detection circuit that turns on the transistor when a cell voltage supplied to the storage element exceeds a reference voltage,
The plurality of power storage elements are charged by the charging unit so that all of the cell voltages supplied to the plurality of power storage elements exceed the reference voltage. The charging system described in.   The charging system according to claim 10, wherein the on / off detection circuit includes a Schmitt trigger circuit having hysteresis.   The charging system according to any one of claims 10 to 16, wherein the storage element is any one of a lithium ion battery cell, an electric double layer capacitor cell, a lithium ion capacitor cell, and an SCiB cell. The charging system according to claim 15 , wherein a common reference voltage is supplied from a reference voltage generation unit to both the on / off detection circuit and the cell voltage detection circuit.   The integrated circuit carrying the electrical storage element monitoring circuit of any one of Claims 1-9.

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