Control system, control method and rechargeable battery protection integrated circuit

Abstract

The present invention provides a control system, a control method and a rechargeable battery protection integrated circuit, which can control the balance of the cell voltages of multiple rechargeable battery cells connected in series with high precision. The rechargeable battery protection device and an external device are provided, wherein the rechargeable battery protection device has: one or more monitoring terminals, which are configured to monitor the potential of one or more negative electrodes of multiple rechargeable battery cells connected in series in a path different from the power supply path; one or more internal wirings, which are between the one or more negative electrodes and the one or more monitoring terminals; one or more internal switches, which are respectively inserted in series into the one or more internal wirings, and the external device has: a balance control circuit, which controls the current flowing through the wiring path including at least one of the one or more internal wirings according to the potential of the one or more monitoring terminals, thereby controlling the balance of the cell voltages of the multiple rechargeable battery cells.

Description

Technical Field

[0001] The invention relates to a control system, a control method and a rechargeable battery protection integrated circuit. Background Art

[0002] Conventionally, there is known a charging device for charging a battery pack having a plurality of rechargeable battery cells connected in series and a midpoint terminal connected between the plurality of rechargeable battery cells. The charging device has a charging control microcomputer that adjusts the voltage balance between the cells by charging and discharging from the midpoint terminal. The charging control microcomputer calculates the voltage of the two cells based on the voltage between the + terminal and the - terminal of the battery pack and the voltage between the midpoint terminal and the - terminal, and adjusts the voltage balance between the cells when the difference between the voltages of the two cells is greater than a predetermined value. On the other hand, the battery pack has a pair of protection FETs between the - terminal and the rechargeable battery cell to protect the plurality of rechargeable battery cells.

[0003] However, due to the on-resistance of a pair of protection FETs between the -terminal and the rechargeable battery cell, a voltage drop occurs, so the inter-terminal voltage between the midpoint terminal and the -terminal is higher than the actual cell voltage. As a result, the accuracy of adjusting the voltage balance between cells may be reduced.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2010-57249 Summary of the invention

[0005] The present disclosure provides a control system, a control method and a rechargeable battery protection integrated circuit capable of controlling the balance of cell voltages of a plurality of rechargeable battery cells connected in series with high accuracy.

[0006] The present disclosure provides a control system having:

[0007] a plurality of rechargeable battery cells connected in series;

[0008] a power path connected in series with the plurality of rechargeable battery cells;

[0009] at least one switching element inserted in series into the power path;

[0010] a rechargeable battery protection device that protects the plurality of rechargeable battery cells by controlling the switch element; and

[0011] an external device that controls the balance of the cell voltages of the plurality of rechargeable battery cells,

[0012] The rechargeable battery protection device comprises:

[0013] an abnormality detection circuit that detects an abnormality of the plurality of rechargeable battery cells;

[0014] one or more monitoring terminals configured to monitor the potential of one or more negative electrodes of the plurality of rechargeable battery cells in a path different from the power supply path;

[0015] one or more internal wirings interposed between the one or more negative electrodes and the one or more monitoring terminals; and

[0016] one or more internal switches, which are respectively inserted in series into the one or more internal wirings and are turned on or off according to the abnormality detection result of the abnormality detection circuit,

[0017] The external device has:

[0018] The balance control circuit controls the current flowing through the wiring path including at least one of the one or more internal wirings based on the potential of the one or more monitoring terminals, thereby controlling the balance of the cell voltages of the plurality of rechargeable battery cells.

[0019] The present disclosure provides a control method performed by a device for monitoring the potential of one or more negative electrodes of a plurality of rechargeable battery cells connected in series.

[0020] The plurality of rechargeable battery cells are protected by controlling at least one switching element inserted in series into a power supply path connected in series with the plurality of rechargeable battery cells by a rechargeable battery protection circuit.

[0021] The rechargeable battery protection circuit has:

[0022] an abnormality detection circuit that detects an abnormality of the plurality of rechargeable battery cells;

[0023] one or more monitoring terminals configured to monitor the potential of the one or more negative electrodes in a path different from the power supply path;

[0024] one or more internal wirings interposed between the one or more negative electrodes and the one or more monitoring terminals; and

[0025] one or more internal switches, which are respectively inserted in series into the one or more internal wirings and are turned on or off according to the abnormality detection result of the abnormality detection circuit,

[0026] The device controls a current flowing through a wiring path including at least one of the one or more internal wirings based on the potential of the one or more monitoring terminals, thereby controlling a balance of cell voltages of the plurality of rechargeable battery cells.

[0027] The present disclosure provides a rechargeable battery protection integrated circuit, which protects a plurality of rechargeable battery cells by controlling at least one switch element inserted in series into a power supply path connected in series with a plurality of rechargeable battery cells connected in series.

[0028] The rechargeable battery protection integrated circuit comprises:

[0029] an abnormality detection circuit that detects an abnormality of the plurality of rechargeable battery cells;

[0030] one or more monitoring terminals configured to monitor the potential of one or more negative electrodes of the plurality of rechargeable battery cells in a path different from the power supply path;

[0031] one or more internal wirings interposed between the one or more negative electrodes and the one or more monitoring terminals; and

[0032] one or more internal switches, which are respectively inserted in series into the one or more internal wirings and are turned on or off according to the abnormality detection result of the abnormality detection circuit,

[0033] The one or more monitoring terminals output the potential of the one or more negative electrodes so that the external device controls the current flowing through the wiring path including at least one of the one or more internal wirings according to the potential of the one or more monitoring terminals, thereby being able to control the balance of the cell voltages of the multiple rechargeable battery cells.

[0034] According to the present disclosure, it is possible to accurately control the balance of the cell voltages of the plurality of rechargeable battery cells connected in series. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 1 is a diagram showing a configuration example of the control system in the first embodiment, and is a diagram showing a first discharge path in a normal state in which abnormalities of a plurality of rechargeable battery cells are not detected.

[0036] Figure 2 1 is a diagram showing a configuration example of the control system in the first embodiment, and is a diagram showing a second discharge path in a normal state in which abnormalities of a plurality of rechargeable battery cells are not detected.

[0037] Figure 3 1 is a diagram showing a configuration example of the control system in the first embodiment, and is a diagram showing a discharge path in a state where overdischarge of at least one of a plurality of rechargeable battery cells is detected.

[0038] Figure 4The diagram shows a configuration example of the control system in the first embodiment, and shows a charging path when a charger is connected in a state where overdischarge of at least one of a plurality of rechargeable battery cells is detected.

[0039] Figure 5 It is a diagram showing a configuration example of the control system in the first embodiment, and is a diagram showing a discharge path in a state where overcharge of a low potential side rechargeable battery cell among a plurality of rechargeable battery cells is detected.

[0040] Figure 6 It is a diagram showing a configuration example of the control system in the first embodiment, and is a diagram showing a discharge path in a state where overcharge of a high potential side rechargeable battery cell among a plurality of rechargeable battery cells is detected.

[0041] Figure 7 It is a diagram showing a configuration example of a control system in the second embodiment, and is a diagram showing a charging path under cell balancing control based on charging and discharging of a low potential side rechargeable battery cell among a plurality of rechargeable battery cells.

[0042] Figure 8 It is a diagram showing a configuration example of a control system in the second embodiment, and is a diagram showing a discharge path under cell balancing control based on charge and discharge of a rechargeable battery cell on the low potential side among a plurality of rechargeable battery cells.

[0043] Fig. 9 It is a diagram showing a configuration example of a control system in the third embodiment, and is a diagram showing a discharge path under cell balancing control based on discharge of a rechargeable battery cell on the low potential side among a plurality of rechargeable battery cells.

[0044] Fig.10 It is a diagram showing a configuration example of a control system in the third embodiment, and is a diagram showing a discharge path under cell balancing control based on discharge of a high potential side rechargeable battery cell among a plurality of rechargeable battery cells.

[0045] Fig.11 It is a diagram showing a configuration example of a control system in the third embodiment, and is a diagram showing a charging path under cell balancing control based on charging of a rechargeable battery cell on a low potential side among a plurality of rechargeable battery cells.

[0046] Fig.12 It is a diagram showing a configuration example of a control system in the fourth embodiment, and is a diagram showing a discharge path under cell balancing control based on discharge of a rechargeable battery cell on the low potential side among a plurality of rechargeable battery cells.

[0047] Fig.13It is a diagram showing a structural example of a control system in the fourth embodiment, and is a diagram showing a charge and discharge path under cell balancing control based on the discharge of a high-potential side charging battery cell or the charging of a low-potential side charging battery cell among a plurality of charging battery cells.

[0048] Fig.14 It is a diagram showing a configuration example of a control system in the fifth embodiment, and is a diagram showing a discharge path under cell balancing control based on discharge of a high potential side rechargeable battery cell among a plurality of rechargeable battery cells.

[0049] Fig.15 It is a diagram showing a configuration example of a control system in the sixth embodiment, and is a diagram showing a discharge path under cell balancing control based on discharge of a high potential side rechargeable battery cell among a plurality of rechargeable battery cells.

[0050] Fig.16 This is a diagram showing an example of switch control and terminal processing in each state.

[0051] Explanation of symbols

[0052] 7, 8 power supply path;

[0053] 13. Switching circuit;

[0054] 21, 22, 23, 24 internal switches;

[0055] 25, 26, 27, 28, 29, 40, 41, 42 switches;

[0056] 30 current control circuit;

[0057] 31, 32, 38 current sources;

[0058] 33 balance control circuit;

[0059] 36, 37 discharge circuit;

[0060] 43 internal switch;

[0061] 44 current detection circuit;

[0062] 51, 52 internal resistance;

[0063] 81 discharge control circuit;

[0064] 82 charging control circuit;

[0065] 83 switch control circuit;

[0066] 85, 86 internal wiring;

[0067] 110 rechargeable battery protection device;

[0068] 120, 121 protection IC;

[0069] 130 charger;

[0070] 140 external devices;

[0071] 141, 142 parasitic diode;

[0072] 143 resistance part;

[0073] 151 battery pack;

[0074] 201, 202 rechargeable battery unit;

[0075] 201a, 202a negative electrode;

[0076] 201b, 202b positive electrode;

[0077] 301, 302, 303, 304, 305, 306 control system. DETAILED DESCRIPTION

[0078] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0079] <First embodiment>

[0080] Figure 1 It is a diagram showing a configuration example of a control system in the first embodiment. Figure 1 The control system 301 shown is a system for controlling the balance of cell voltages of a plurality of (two in this example) rechargeable battery cells 201 and 202 connected in series. The control system 301 includes an external device 140 and a battery pack 151 .

[0081] The external device 140 is a device connected to the battery pack 151. The external device 140 may be a charger for charging the battery pack 151, or may be a device that operates using power supplied from the battery pack 151. Specific examples of devices that operate using power supplied from the battery pack 151 include electronic devices such as smartphones, tablet computers, and mobile phones.

[0082] The external device 140 includes a balance control circuit 33 that controls the balance of the cell voltages of the plurality of rechargeable battery cells. The balance control circuit 33 will be described later.

[0083] The battery pack 151 is a component that accommodates a plurality of rechargeable battery cells 201 and 202 connected in series, and is used by being connected to the external device 140. The battery pack 151 includes a plurality of rechargeable battery cells 201 and 202 and a rechargeable battery protection device 110.

[0084] The plurality of rechargeable battery cells 201, 201 are rechargeable battery cells. Specific examples of the rechargeable battery include lithium ion batteries, lithium polymer batteries, and the like.

[0085] The rechargeable battery cell 201 is an example of a first rechargeable battery cell, and has a positive electrode 201b and a negative electrode 201a. The positive electrode 201b is an example of a first positive electrode. The negative electrode 201a is an example of a first negative electrode with the lowest potential among a plurality of negative electrodes that are electrodes on the low potential side of each of the plurality of rechargeable battery cells. The rechargeable battery cell 202 is an example of a second rechargeable battery cell, and has a positive electrode 202b and a negative electrode 202a. The positive electrode 202b is an example of a second positive electrode. The negative electrode 202a is connected to the positive electrode 201b.

[0086] The rechargeable battery protection device 110 operates the plurality of rechargeable battery cells 201 and 202 as power sources, and protects the plurality of rechargeable battery cells 201 and 202 from over-discharge, etc. by controlling the charge and discharge of the plurality of rechargeable battery cells 201 and 202. The rechargeable battery protection device 110 includes, for example, a switch circuit 13, a protection IC 120, resistor elements R1, R2, R3, R4, and R5, capacitor elements C1 and C2, and a substrate (not shown) on which they are mounted.

[0087] As a specific example of the substrate, a printed circuit board is listed. Terminal B-, terminal B+, terminal BM, terminal P-, terminal P+, terminal BSL and terminal BSM are provided on the substrate. Each of these terminals is, for example, an electrode formed on the substrate. In addition, power supply paths 7 and 8 are provided on the substrate.

[0088] Terminal B- is an example of a negative terminal of a battery, and is connected to the negative electrode 201a of the rechargeable battery cell 201 having the lowest potential among the rechargeable battery cells connected in series. Terminal B+ is an example of a positive terminal of a battery, and is connected to the positive electrode 202b of the rechargeable battery cell 202 having the highest potential among the rechargeable battery cells connected in series. Terminal BM is an example of a battery monitoring terminal, and is connected between adjacent rechargeable battery cells among the rechargeable battery cells connected in series. In this example, terminal BM is connected to the positive electrode 201b of the rechargeable battery cell 201 and the negative electrode 202a of the rechargeable battery cell 202.

[0089] The terminal P− is an example of a load negative terminal, and is connected to a ground terminal of the external device 140 . The terminal P+ is an example of a load positive terminal, and is connected to a power supply terminal of the external device 140 .

[0090] The terminal B- and the terminal P- are connected via a negative power path 7. The power path 7 is a current path between the terminal B- and the terminal P-, through which a charging current or a discharging current flows. The power path 7 is connected in series with the negative electrode 201a of the rechargeable battery cell 201.

[0091] The terminal B+ and the terminal P+ are connected via a positive power path 8. The power path 8 is a current path between the terminal B+ and the terminal P+, through which a charging current or a discharging current flows. The power path 8 is connected in series with the positive electrode 202b of the rechargeable battery cell 202.

[0092] The terminal BSL is an example of a first monitoring terminal, and is provided so as to be able to monitor the potential of the negative electrode 201a of the rechargeable battery cell 201 in a path different from the power supply paths 7 and 8. The terminal BSL is connected to the low potential side monitoring unit of the balance control circuit 33. The terminal BSM is an example of a second monitoring terminal, and is provided so as to be able to monitor the potential of the negative electrode 202a of the rechargeable battery cell 202 in a path different from the power supply paths 7 and 8. The terminal BSM is connected to the high potential side monitoring unit of the balance control circuit 33.

[0093] The switch circuit 13 is inserted in series into the power supply path 7 between the terminal B- and the terminal P-. For example, the switch circuit 13 is a series circuit in which the charge control transistor 11 and the discharge control transistor 12 are connected in series. By turning off the charge control transistor 11, the power supply path 7 through which the charging current of the rechargeable battery cells 201 and 202 flows is cut off, and the flow of the charging current of the rechargeable battery cells 201 and 202 is prohibited. By turning off the discharge control transistor 12, the power supply path 7 through which the discharge current of the rechargeable battery cells 201 and 202 flows is cut off, and the flow of the discharge current of the rechargeable battery cells 201 and 202 is prohibited.

[0094] The charge control transistor 11 and the discharge control transistor 12 are, for example, N-channel MOSFETs (Metal Oxide Semiconductor Field Effect Transistors). The charge control transistor 11 is a switch element that is inserted in series into the power supply path 7 in such a way that the forward direction of the parasitic diode of the charge control transistor 11 coincides with the flow direction of the discharge current of the rechargeable battery cells 201 and 202. The discharge control transistor 12 is a switch element that is inserted in series into the power supply path 7 in such a way that the forward direction of the parasitic diode of the discharge control transistor 12 coincides with the flow direction of the charge current of the rechargeable battery cells 201 and 202.

[0095] The protection IC 120 is an example of a rechargeable battery protection integrated circuit. The protection IC 120 operates the rechargeable battery cells 201 and 202 as a power source. The protection IC 120 protects the rechargeable battery cells 201 and 202 from over-discharge, etc. by controlling the switch circuit 13. For example, the protection IC 120 protects the rechargeable battery cells 201 and 202 from charging abnormalities (for example, over-charging, over-current in the charging direction (charging over-current), etc.) by turning off the charging control transistor 11. On the other hand, the protection IC 120 protects the rechargeable battery cells 201 and 202 from discharge abnormalities (for example, over-discharge, over-current in the discharge direction (discharging over-current), etc.) by turning off the discharge control transistor 12.

[0096] The protection IC 120 has a terminal VDD, a terminal VSS, a terminal VBM, a terminal DO, a terminal CO, a terminal VM, a terminal BS1 , and a terminal BS2 . These terminals are external connection terminals for connecting the internal circuit of the protection IC 120 to the outside of the protection IC 120 .

[0097] The terminal VDD is an example of a positive power supply terminal connected to the power supply path 8, and is connected to the positive electrode 202b of the rechargeable battery cell 202 via the terminal B+. In this example, the terminal VDD is connected to the positive electrode 202b of the rechargeable battery cell 202 via the resistor R1 and the terminal B+. The resistor R1 and the capacitor C1 form a CR filter.

[0098] The terminal VSS is an example of a negative power supply terminal connected to the power supply path 7 between the negative electrode 201a of the rechargeable battery cell 201 and the switch circuit 13, and is a ground terminal connected to the negative electrode 201a of the rechargeable battery cell 201 via the terminal B-.

[0099] The terminal VBM is an example of an intermediate monitoring terminal provided to monitor the potential (intermediate potential) between adjacent rechargeable battery cells in the series-connected rechargeable battery cells. In this example, the terminal VBM is connected between the positive electrode 201b of the rechargeable battery cell 201 and the negative electrode 202a of the rechargeable battery cell 202 via the resistor element R2 and the terminal BM. The resistor element R2 and the capacitor element C2 constitute a CR filter.

[0100] The terminal CO is an example of a charge control terminal that outputs a signal for prohibiting charging of the rechargeable battery cells 201 and 202 , and is connected to a control electrode (for example, a gate in the case of a MOSFET) of the charge control transistor 11 .

[0101] The terminal DO is an example of a discharge control terminal that outputs a signal for prohibiting the discharge of the rechargeable battery cells 201 and 202 , and is connected to a control electrode (for example, a gate in the case of a MOSFET) of the discharge control transistor 12 .

[0102] The terminal VM is an example of a monitoring terminal for monitoring the potential of the terminal P-, and is connected to the power supply path 7 between the terminal P- and the switch circuit 13. The terminal VM is connected to the terminal P- via the resistor element R3.

[0103] The terminal BS1 is an example of a first monitoring terminal, similar to the terminal BSL, and is provided so as to be able to monitor the potential of the negative electrode 201a of the rechargeable battery cell 201 in a path different from the power supply paths 7 and 8. In this example, the terminal BS1 is connected to the terminal BSL via the resistor element R5. The current value of the current flowing through the wiring path including the terminal BS1 and the terminal BSL can be adjusted by the resistance value of the resistor element R5.

[0104] The terminal BS2 is an example of a second monitoring terminal, similar to the terminal BSM, and is provided to monitor the potential of the negative electrode 202a of the rechargeable battery cell 202 in a path different from the power supply paths 7 and 8. The terminal BS2 is connected to the terminal BSM via the resistor element R4. The current value of the current flowing through the wiring path including the terminal BS2 and the terminal BSM can be adjusted by the resistance value of the resistor element R4.

[0105] The protection IC 120 includes a discharge control circuit 81 , a charge control circuit 82 , a switch control circuit 83 , internal wirings 85 and 86 , internal switches 21 , 22 , 23 , 24 , and 43 , and internal resistors 51 and 52 .

[0106] The discharge control circuit 81 has an abnormality detection circuit that detects abnormal discharge of the rechargeable battery cells 201 and 202. The discharge control circuit 81 is an example of a control circuit that controls the switch circuit 13 according to the detection result of the abnormality detection circuit when the abnormality detection circuit detects abnormal discharge of the rechargeable battery cells 201 and 202. The charge control circuit 82 has an abnormality detection circuit that detects abnormal charge of the rechargeable battery cells 201 and 202. The charge control circuit 82 is an example of a control circuit that controls the switch circuit 13 according to the detection result of the abnormality detection circuit when the abnormality detection circuit detects abnormal charge of the rechargeable battery cells 201 and 202.

[0107] The charging control circuit 82 has an overcharge detection circuit (an example of an abnormality detection circuit) for detecting overcharge (an example of a predetermined abnormality) of the rechargeable battery cells 201 and 202. The overcharge detection circuit monitors the power supply voltage VD between the terminal VDD and the terminal VSS. The overcharge detection circuit may also monitor the cell voltage of each of the plurality of rechargeable battery cells 201 and 202. For example, the overcharge detection circuit monitors the voltage between the terminal VBM and the terminal VSS as the cell voltage VC1 of the rechargeable battery cell 201, and monitors the voltage between the terminal VDD and the terminal VBM as the cell voltage VC2 of the rechargeable battery cell 202. When the overcharge detection circuit detects that at least one of the cell voltage VC1 and the cell voltage VC2 is greater than or equal to a predetermined overcharge detection threshold value Vdet1, the charging control circuit 82 outputs a charging control signal (overcharge protection operation) for turning off the charging control transistor 11 from the terminal CO. By turning off the charging control transistor 11, the current in the charging direction of the rechargeable battery cells 201 and 202 is cut off, thereby preventing the rechargeable battery cells 201 and 202 from being overcharged.

[0108] The discharge control circuit 81 has an over-discharge detection circuit (an example of an abnormality detection circuit) for detecting over-discharge (an example of a predetermined abnormality) of the rechargeable battery cells 201 and 202. The over-discharge detection circuit monitors the power supply voltage VD between the terminal VDD and the terminal VSS. The over-discharge detection circuit may also monitor the cell voltages of the plurality of rechargeable battery cells 201 and 202. For example, the over-discharge detection circuit monitors the voltage between the terminal VBM and the terminal VSS as the cell voltage VC1 of the rechargeable battery cell 201, and monitors the voltage between the terminal VDD and the terminal VBM as the cell voltage VC2 of the rechargeable battery cell 202. When the over-discharge detection circuit detects that at least one of the cell voltage VC1 and the cell voltage VC2 is less than a predetermined over-discharge detection threshold value Vdet2, the discharge control circuit 81 outputs a discharge control signal (over-discharge protection operation) for turning off the discharge control transistor 12 from the terminal DO. By turning off the discharge control transistor 12, the current in the discharge direction of the rechargeable battery cells 201 and 202 is cut off, thereby preventing the rechargeable battery cells 201 and 202 from being over-discharged.

[0109] The discharge control circuit 81 has a discharge overcurrent detection circuit (an example of an abnormality detection circuit) that detects a discharge overcurrent (an example of a predetermined abnormality) of the rechargeable battery cells 201 and 202. The discharge overcurrent detection circuit monitors the current detection voltage VI between the terminal VM and the terminal VSS. When the discharge overcurrent detection circuit detects that the current detection voltage VI is greater than the predetermined discharge overcurrent detection threshold value Vdet3, the discharge control circuit 81 outputs a discharge control signal (discharge overcurrent protection action) that turns off the discharge control transistor 12 from the terminal DO. By turning off the discharge control transistor 12, the current in the discharge direction of the rechargeable battery cells 201 and 202 is cut off, thereby preventing the overcurrent from flowing in the direction of discharging the rechargeable battery cells 201 and 202.

[0110] The charging control circuit 82 has a charging overcurrent detection circuit (an example of an abnormality detection circuit) that detects a charging overcurrent (an example of a predetermined abnormality) of the charging battery cells 201 and 202. The charging overcurrent detection circuit monitors the current detection voltage VI between the terminal VM and the terminal VSS. When the charging overcurrent detection circuit detects that the current detection voltage VI is below the predetermined charging overcurrent detection threshold value Vdet4, the charging control circuit 82 outputs a charging control signal (charging overcurrent protection action) that turns off the charging control transistor 11 from the terminal CO. By turning off the charging control transistor 11, the current in the charging direction of the charging battery cells 201 and 202 is cut off, thereby preventing the overcurrent from flowing in the direction of charging the charging battery cells 201 and 202.

[0111] The internal wiring 85 is a current path between the cathode 201a and the terminal BSL, more specifically, between the terminal VSS and the terminal BS1. The internal wiring 86 is a current path between the cathode 202a and the terminal BSM, more specifically, between the terminal VBM and the terminal BS2.

[0112] The switch control circuit 83 is a circuit that turns on or off each of the plurality of internal switches 21 , 22 , 23 , 24 , and 43 according to the abnormality detection result of the abnormality detection circuit.

[0113] The internal switch 21 is inserted in series into the internal wiring 85. The internal switch 22 is set to be able to short-circuit the terminal BS1 and the terminal VM. The internal switch 23 is inserted in series into the internal wiring 86. The internal switch 24 is set to be able to short-circuit the terminal BS2 and the terminal VM. The internal switch 43 is set to be able to select a state in which the terminal VM is pulled down to the terminal VSS via the internal resistor 51, a state in which the terminal VM is pulled up to the terminal VDD via the internal resistor 52, and a state in which neither the terminal VM is pulled up nor the terminal VM is pulled down. The plurality of internal switches 21, 22, 23, 24, and 43 are respectively turned on or off by the switch control circuit 83 according to the abnormality detection result of the abnormality detection circuit described above.

[0114] The external device 140 includes a balance control circuit 33. The balance control circuit 33 controls the current flowing through the wiring path including at least one of the plurality of internal wirings 85 and 86 according to the potential of the plurality of terminals BSL and BSM, thereby controlling the balance of the cell voltages of the plurality of rechargeable battery cells 201 and 202. In this example, the external device 140 includes a current control circuit 30 that controls the current flowing through the wiring path including at least one of the plurality of internal wirings 85 and 86. The balance control circuit 33 controls the balance of the cell voltages of the plurality of rechargeable battery cells 201 and 202 by controlling the current control circuit 30.

[0115] The current control circuit 30 includes, for example, a plurality of current sources 31 and 32 connected in parallel to corresponding rechargeable battery cells among the plurality of rechargeable battery cells 201 and 202. The balance control circuit 33 controls the current control circuit 30, thereby controlling the balance of the cell voltages of the plurality of rechargeable battery cells 201 and 202 so that a constant current flows from one of the plurality of current sources 31 and 32 to a wiring path including at least one of the plurality of internal wirings 85 and 86.

[0116] The current source 32 is, for example, a constant current source connected in parallel with the rechargeable battery cell 201. The balance control circuit 33 causes the constant current generated by the current source 32 to flow through the wiring path DR1 (see Figure 1 ), thereby controlling the discharge amount of the rechargeable battery cell 201. Thus, even if the resistance value of the resistor R4 in the battery pack 151 changes due to aging, design changes, etc., the external device 140 can make the discharge current of the desired discharge amount flow through the wiring path DR1 including the rechargeable battery cell 201, the internal wiring 86, and the power supply path 7.

[0117] The current source 31 is, for example, a constant current source connected in parallel with the rechargeable battery cell 202. The balance control circuit 33 causes the constant current generated by the current source 31 to flow through the wiring path DR2 (see FIG. 1 ) including the internal wiring 86 and the power supply path 8. Figure 2 ), thereby controlling the discharge amount of the rechargeable battery cell 202. Thus, even if the resistance value of the resistor R4 in the battery pack 151 changes due to aging, design changes, etc., the external device 140 can make the discharge current of the desired discharge amount flow through the wiring path DR2 including the rechargeable battery cell 202, the internal wiring 86, and the power supply path 7.

[0118] The current control circuit 30 includes, for example, a switching circuit including a plurality of switches 25 and 26 connected in parallel to corresponding rechargeable battery cells 201 and 202. The balance control circuit 33 controls the switching circuit to control the balance of the cell voltages of the plurality of rechargeable battery cells 201 and 202. The switching circuit switches between conduction and non-conduction of a wiring path including at least one internal wiring of the plurality of internal wirings 85 and 86.

[0119] The switch 26 is connected in parallel with the rechargeable battery cell 201 and in series with the current source 32. The switch 26 switches the wiring path DR1 (see FIG. 1 ) including the internal wiring 86 and the power supply path 7 according to the switching signal from the balance control circuit 33. Figure 1 ) is switched between conduction and non-conduction. Thus, the external device 140 can control a desired discharge amount in the wiring path DR1 including the rechargeable battery cell 201, the internal wiring 86, and the power supply path 7.

[0120] The switch 25 is connected in parallel with the rechargeable battery cell 202 and in series with the current source 31. The switch 25 switches the wiring path DR2 (see FIG. 1 ) including the internal wiring 86 and the power supply path 8 according to the switching signal from the balance control circuit 33. Figure 2 ) is switched between conduction and non-conduction. Thus, the external device 140 can control the desired discharge amount in the wiring path DR2 including the rechargeable battery cell 202, the internal wiring 86, and the power supply path 8.

[0121] Fig.16 FIG. 1 is a diagram showing an example of switch control and terminal processing in each state. Fig.16 , an operation example of the control system is described.

[0122] When overcharging and overcurrent of the rechargeable battery cells 201 and 202 are not detected, the charge control circuit 82 turns on the charge control transistor 11. On the other hand, when at least one of overcharging and overcurrent of the rechargeable battery cells 201 and 202 is detected, the charge control circuit 82 turns off the charge control transistor 11.

[0123] When overdischarge and discharge overcurrent of the rechargeable battery cells 201 and 202 are not detected, the discharge control circuit 81 turns on the discharge control transistor 12. On the other hand, when at least one of overdischarge and discharge overcurrent of the rechargeable battery cells 201 and 202 is detected, the discharge control circuit 81 turns off the discharge control transistor 12.

[0124] Figure 1 and Figure 2 Indicates a normal state in which no abnormality is detected in the rechargeable battery cells 201 and 202. When overcharge, overdischarge, discharge overcurrent, and charge overcurrent of the rechargeable battery cells 201 and 202 are not detected (normal state), the switch control circuit 83 turns on the internal switch 21, turns off the internal switch 22, turns on the internal switch 23, turns off the internal switch 24, and turns off the internal switch 43. As a result, the terminal BSL has substantially the same potential as the terminal B-, the terminal VSS, and the negative electrode 201a, and the terminal BSM has substantially the same potential as the terminal BM, the terminal VBM, and the negative electrode 202a.

[0125] Therefore, in Figure 1 , 2 In the normal state shown in FIG. 1 , the balance control circuit 33 can measure the cell voltage of the rechargeable battery cell 201 with high accuracy by monitoring the potential difference between the terminal BSM and the terminal P-. Figure 1 , 2 In the normal state shown in FIG. 1 , the balance control circuit 33 can measure the cell voltage of the rechargeable battery cell 202 with high accuracy by monitoring the potential difference between the terminal BSM and the terminal P+. Figure 1 , 2 In the normal state shown, the balance control circuit 33 can measure the cell voltage (total cell voltage VC) to which the cell voltages of the rechargeable battery cells 201 and 202 are added with high accuracy by monitoring the potential difference between the terminal BSL and the terminal P+.

[0126] Figure 1The figure shows a case where the cell voltage of the rechargeable battery cell 201 is higher than the cell voltage of the rechargeable battery cell 202 in a normal state. When the balance control circuit 33 determines that the cell voltage of the rechargeable battery cell 201 is higher than the cell voltage of the rechargeable battery cell 202, the balance control circuit 33 switches the switch 26 from off to on in order to reduce the cell voltage of the rechargeable battery cell 201, thereby causing the rechargeable battery cell 201 to discharge in the wiring path DR1.

[0127] Figure 2 The figure shows a case where the cell voltage of the rechargeable battery cell 202 is higher than the cell voltage of the rechargeable battery cell 201 in a normal state. When the balance control circuit 33 determines that the cell voltage of the rechargeable battery cell 202 is higher than the cell voltage of the rechargeable battery cell 201, the switch 25 is switched from off to on in order to reduce the cell voltage of the rechargeable battery cell 202, thereby causing the rechargeable battery cell 202 to discharge in the wiring path DR2.

[0128] When the difference between the cell voltage of the rechargeable battery cell 201 and the cell voltage of the rechargeable battery cell 202 is equal to or less than a predetermined threshold value, the balance control circuit 33 turns off both switches 25 and 26 to stop the discharge of the rechargeable battery cells 201 and 202 by the cell balance control.

[0129] Figure 3 1 is a diagram showing a configuration example of a control system in the first embodiment, and is a diagram showing a discharge path in a state where overdischarge of at least one of a plurality of rechargeable battery cells is detected. In a state where overdischarge of at least one of a plurality of rechargeable battery cells 201 and 202 is detected, the switch control circuit 83 turns off the internal switch 21, turns on the internal switch 22, turns off the internal switch 23, turns on the internal switch 24, and sets the internal switch 43 to the pull-up side. As a result, the terminal BSL (terminal BS1) and the terminal BSM (terminal BS2) are short-circuited with the terminal P- (terminal VM), and the terminal P- is pulled up to the terminal VDD. Therefore, in a state where overdischarge is detected, the leakage current path DR3 flowing from the power supply path 8 to the terminals BS1 and BS2 via the power supply terminal VDD of the external device 140, the resistor portion 143 of the external device 140, and the parasitic diodes 141 and 142 can be cut off. As a result, the discharge of the rechargeable battery cells 201 and 202 can be suppressed.

[0130] Figure 41 is a diagram showing a configuration example of a control system in the first embodiment, and is a diagram showing a charging path when a charger is connected in a state where overdischarge of at least one of a plurality of rechargeable battery cells is detected. When the charger 130 is connected in a state where overdischarge of at least one of a plurality of rechargeable battery cells 201, 202 is detected, the switch control circuit 83 turns on the internal switch 21, turns off the internal switch 22, turns on the internal switch 23, turns off the internal switch 24, and sets the internal switch 43 to the pull-up side. As a result, the terminal BSL (terminal BS1) is short-circuited with the terminal P- (terminal VSS), the terminal BSM (terminal BS2) is short-circuited with the terminal BM (terminal VBM), and the terminal P- is pulled up to the terminal VDD. Therefore, when the charger 130 is connected in a state where overdischarge is detected, the rechargeable battery cells 201, 202 can be charged through the wiring path CR1 from the charger 130 to the rechargeable battery cells 201, 202. In addition, the external device 140 can be free from the parasitic diodes 141, 142 (refer to Figure 3 )'s forward voltage, the cell voltages of the rechargeable battery cells 201 and 202 are measured with high accuracy, thereby preventing unnecessary repetition of pre-charging and rapid charging.

[0131] Figure 5 1 is a diagram showing a configuration example of a control system in the first embodiment, and is a diagram showing a discharge path in a state where an overcharge of a low-potential side rechargeable battery cell among a plurality of rechargeable battery cells is detected. In a state where only one of the plurality of rechargeable battery cells 201 and 202 is detected to be overcharged, the switch control circuit 83 turns off the internal switch 21, turns on the internal switch 22, turns on the internal switch 23, turns off the internal switch 24, and turns off the internal switch 43. As a result, the terminal BSL (terminal BS1) and the terminal P- (terminal VM) are short-circuited, the terminal BSM (terminal BS2) and the terminal BM (terminal VBM) are short-circuited, and the terminal P- is high impedance (Hi-Z). When the balance control circuit 33 determines that the cell voltage of the rechargeable battery cell 201 is higher than the cell voltage of the rechargeable battery cell 202, in order to reduce the cell voltage of the rechargeable battery cell 201, the switch 26 is switched from off to on, thereby causing the rechargeable battery cell 201 to discharge in the wiring path DR1. Therefore, even in a state where overcharge is detected, the rechargeable battery cells 201 can be discharged by cell balancing control.

[0132] Figure 61 is a diagram showing a configuration example of a control system in the first embodiment, and is a diagram showing a discharge path in a state where an overcharge of a high potential side rechargeable battery cell among a plurality of rechargeable battery cells is detected. In a state where only one of the plurality of rechargeable battery cells 201 and 202 is detected to be overcharged, the switch control circuit 83 turns off the internal switch 21, turns on the internal switch 22, turns on the internal switch 23, turns off the internal switch 24, and turns off the internal switch 43. As a result, the terminal BSL (terminal BS1) and the terminal P- (terminal VM) are short-circuited, the terminal BSM (terminal BS2) and the terminal BM (terminal VBM) are short-circuited, and the terminal P- is high impedance (Hi-Z). When the balance control circuit 33 determines that the cell voltage of the rechargeable battery cell 202 is higher than the cell voltage of the rechargeable battery cell 201, in order to reduce the cell voltage of the rechargeable battery cell 202, the switch 25 is switched from off to on, thereby causing the rechargeable battery cell 202 to discharge in the wiring path DR2. Therefore, even in a state where overcharge is detected, the rechargeable battery cells 202 can be discharged by cell balancing control.

[0133] The status of each switch in other abnormal detection modes is as follows Fig.16 In addition, Fig.16 BS1 detection state indicates that the abnormality detection circuit detects an abnormality of overcurrent flowing through the internal wiring 85 connecting the terminal BS1 and the terminal VSS. BS2 detection state indicates that the abnormality detection circuit detects an abnormality of overcurrent flowing through the internal wiring 86 connecting the terminal BS2 and the terminal VBM.

[0134] <Second embodiment>

[0135] Figure 7 It is a diagram showing a configuration example of a control system in the second embodiment, and is a diagram showing a charging path under cell balancing control based on charging and discharging of a low potential side rechargeable battery cell among a plurality of rechargeable battery cells. Figure 8 1 is a diagram showing a configuration example of a control system in a second embodiment, and is a diagram showing a discharge path under cell balancing control based on the charge and discharge of a rechargeable battery cell on the low potential side among a plurality of rechargeable battery cells. In the second embodiment, the description of the same configuration as that of the above embodiment is omitted by citing the above description.

[0136] exist Figure 7 , 8In the control system 302 shown, the external device 140 has a current control circuit 30 that controls the current flowing through a wiring path including at least one of a plurality of internal wirings 85 and 86. The current control circuit 30 has a current source 38 connected in series with the internal wiring 86 and a switching circuit including a switch 27 connected in series with the current source 38.

[0137] Figure 7 and Figure 8 This indicates a normal state where no abnormality of the rechargeable battery cells 201 and 202 is detected. Figure 7 , 8 In the normal state shown in FIG. 1 , the balance control circuit 33 uses the wiring path CR2 (see FIG. Figure 7 ) to charge the rechargeable battery cell 201, or to charge the rechargeable battery cell 201 by using the charging current flowing in the wiring path DR1 (refer to Figure 8 ) discharges the rechargeable battery cell 201, so that the cell voltage of the rechargeable battery cell 201 approaches the cell voltage of the rechargeable battery cell 202.

[0138] Figure 7 The figure shows a case where the cell voltage of the rechargeable battery cell 201 is lower than the cell voltage of the rechargeable battery cell 202 in a normal state. When the balance control circuit 33 determines that the cell voltage of the rechargeable battery cell 201 is lower than the cell voltage of the rechargeable battery cell 202, the switch 27 is switched from off to on in order to increase the cell voltage of the rechargeable battery cell 201, thereby charging the rechargeable battery cell 201 through the wiring path CR2. The rechargeable battery cell 201 is charged by the current output by the current source 38. The current source 38 is, for example, a constant current source.

[0139] Figure 8 The figure shows a case where the cell voltage of the rechargeable battery cell 201 is higher than the cell voltage of the rechargeable battery cell 202 in a normal state. When the balance control circuit 33 determines that the cell voltage of the rechargeable battery cell 201 is higher than the cell voltage of the rechargeable battery cell 202, the switch 26 is switched from off to on in order to reduce the cell voltage of the rechargeable battery cell 201, thereby discharging the rechargeable battery cell 201 in the wiring path DR1. The rechargeable battery cell 201 is discharged by the current output by the current source 32. The current source 32 is, for example, a constant current source.

[0140] <Third embodiment>

[0141] Fig. 9 It is a diagram showing a configuration example of a control system in the third embodiment, and is a diagram showing a discharge path under cell balancing control based on discharge of a rechargeable battery cell on the low potential side among a plurality of rechargeable battery cells. Fig.10 It is a diagram showing a configuration example of a control system in the third embodiment, and is a diagram showing a discharge path under cell balancing control based on discharge of a high potential side rechargeable battery cell among a plurality of rechargeable battery cells. Fig.11 1 is a diagram showing a configuration example of a control system in a third embodiment, and is a diagram showing a charging path under cell balancing control based on charging of a rechargeable battery cell on the low potential side among a plurality of rechargeable battery cells. In the third embodiment, the description of the same configuration as that of the above-mentioned embodiment is omitted by citing the above-mentioned description.

[0142] exist Fig. 9 , 10 In the control system 303 shown in FIG. 11 , the protection IC 120 does not have the terminals BS1 and BSL and the internal wiring 85 . Fig. 9 , 10 , 11 represent a normal state in which no abnormality of the rechargeable battery cells 201, 202 is detected.

[0143] Fig. 9 The figure shows a case where the cell voltage of the rechargeable battery cell 201 is higher than the cell voltage of the rechargeable battery cell 202 in a normal state. When the balance control circuit 33 determines that the cell voltage of the rechargeable battery cell 201 is higher than the cell voltage of the rechargeable battery cell 202, the switch 26 is switched from off to on in order to reduce the cell voltage of the rechargeable battery cell 201, thereby discharging the rechargeable battery cell 201 in the wiring path DR1. The rechargeable battery cell 201 is discharged by the current output by the current source 32. The current source 32 is, for example, a constant current source.

[0144] Fig.10 The figure shows a case where the cell voltage of the rechargeable battery cell 202 is higher than the cell voltage of the rechargeable battery cell 201 in a normal state. When the balance control circuit 33 determines that the cell voltage of the rechargeable battery cell 202 is higher than the cell voltage of the rechargeable battery cell 201, the switch 25 is switched from off to on in order to reduce the cell voltage of the rechargeable battery cell 202, thereby discharging the rechargeable battery cell 202 in the wiring path DR2. The rechargeable battery cell 202 is discharged by the current output by the current source 31. The current source 31 is, for example, a constant current source.

[0145] Fig.11The figure shows a case where the cell voltage of the rechargeable battery cell 201 is lower than the cell voltage of the rechargeable battery cell 202 in a normal state. When the balance control circuit 33 determines that the cell voltage of the rechargeable battery cell 201 is lower than the cell voltage of the rechargeable battery cell 202, the switch 27 is switched from off to on in order to increase the cell voltage of the rechargeable battery cell 201, thereby charging the rechargeable battery cell 201 through the wiring path CR2. The rechargeable battery cell 201 is charged by the current output by the current source 38. The current source 38 is, for example, a constant current source.

[0146] <Fourth embodiment>

[0147] Fig.12 It is a diagram showing a configuration example of a control system in the fourth embodiment, and is a diagram showing a discharge path under cell balancing control based on discharge of a rechargeable battery cell on the low potential side among a plurality of rechargeable battery cells. Fig.13 1 is a diagram showing a configuration example of a control system in a fourth embodiment, and is a diagram showing a charge and discharge path under cell balancing control based on the discharge of a high potential side rechargeable battery cell or the charge of a low potential side rechargeable battery cell among a plurality of rechargeable battery cells. In the fourth embodiment, the description of the same configuration as that of the above-mentioned embodiment is omitted by citing the above-mentioned description. In the control system 301 and the like in the above-mentioned embodiment, the cell balancing discharge path through which the discharge current flows passes through the external device 140. In contrast, in the fourth embodiment, Fig.12 , 13 In the control system 304 shown, a cell balancing discharge path through which a discharge current (excluding a control current described later) flows is located on the battery pack 151 side.

[0148] Fig.12 The figure shows a case where the cell voltage of the rechargeable battery cell 201 is higher than the cell voltage of the rechargeable battery cell 202 in a normal state. When the balance control circuit 33 determines that the cell voltage of the rechargeable battery cell 201 is higher than the cell voltage of the rechargeable battery cell 202, the switch 29 is switched from off to on in order to reduce the cell voltage of the rechargeable battery cell 201. Thus, a control current is generated that flows in the wiring path DR5 from the positive electrode 201b of the rechargeable battery cell 201 via the terminal BM, the terminal VBM, the terminal BS2, the terminal BSM, the switch 29, the terminal P-, the switch circuit 13 and the terminal B- to the negative electrode 201a of the rechargeable battery cell 201.

[0149] The rechargeable battery protection device 110 includes: a current detection circuit 44 that detects the current flowing in the internal wiring 86 under the control of the balance control circuit 33; and a plurality of discharge circuits 36 and 37 that are respectively provided for the plurality of rechargeable battery cells 201 and 202. The current detection circuit 44 and the discharge circuits 36 and 37 are provided outside the battery IC 121 and mounted on the substrate. The discharge circuit 36 ​​discharges the corresponding rechargeable battery cell 201 of the rechargeable battery cells 201 and 202 based on the current detection result of the current detection circuit 44. The discharge circuit 37 discharges the corresponding rechargeable battery cell 202 of the rechargeable battery cells 201 and 202 based on the current detection result of the current detection circuit 44.

[0150] In this example, the current detection circuit 44 includes a resistor R7 connected in series to the internal wiring 86, and detects a voltage drop in the resistor R7 caused by the control current. The resistor R7 is inserted in series in the current path between the terminal BM (negative electrode 202a) and the terminal VBM.

[0151] The discharge circuit 36 ​​includes a switch 41 that discharges a corresponding rechargeable battery cell 201 among the plurality of rechargeable battery cells 201 and 202 according to a voltage drop generated in the resistor R7, and a resistor R9 that is connected in series with the switch 41. The series circuit of the switch 41 and the resistor R9 is connected in parallel with the rechargeable battery cell 201. The switch 41 is, for example, a P-channel MOS transistor having a source connected to one end of the resistor R7, a drain connected to one end of the resistor R9, and a gate connected to the other end (terminal VBM) of the resistor R7. The other end of the resistor R9 is connected to the terminal VSS.

[0152] The discharge circuit 37 includes a switch 40 that discharges a corresponding rechargeable battery cell 202 among the plurality of rechargeable battery cells 201 and 202 according to a voltage drop generated in the resistor R8, and a resistor R8 connected in series with the switch 40. The series circuit of the switch 40 and the resistor R8 is connected in parallel with the rechargeable battery cell 202. The switch 40 is, for example, an N-channel MOS transistor having a source connected to one end of the resistor R7, a drain connected to one end of the resistor R8, and a gate connected to the other end (terminal VBM) of the resistor R7. The other end of the resistor R8 is connected to the terminal VDD.

[0153] The balance control circuit 33 turns on the switch 29 to flow the control current, and when the current detection circuit 44 detects the voltage drop above the threshold value using the resistor R7, the discharge circuit 36 ​​turns on the switch 41 connected in parallel with the rechargeable battery cell 201 to perform cell balance discharge. As a result, a discharge current is generated that flows in the wiring path DR4 from the positive electrode 201b of the rechargeable battery cell 201 via the terminal BM, the resistor R9, the switch 41, and the terminal B- to the negative electrode 201a of the rechargeable battery cell 201. The resistor R9 is an element for adjusting (limiting) the current value of the discharge current.

[0154] Fig.13 The figure shows a case where the cell voltage of the rechargeable battery cell 202 is higher than the cell voltage of the rechargeable battery cell 201 in a normal state. When the balance control circuit 33 determines that the cell voltage of the rechargeable battery cell 202 is higher than the cell voltage of the rechargeable battery cell 201, the switch 28 is switched from off to on in order to reduce the cell voltage of the rechargeable battery cell 202. Thus, a control current is generated that flows in the wiring path CR4 from the power supply V of the external device 140 via the switch 28, the terminal BSM, the terminal BS2, the terminal VBM, and the terminal BM to the positive electrode 201b of the rechargeable battery cell 201.

[0155] When the balance control circuit 33 turns on the switch 28 to flow the control current, and the current detection circuit 44 detects the voltage drop above the threshold value using the resistor element R7, the discharge circuit 37 turns on the switch 40 connected in parallel with the rechargeable battery cell 202 to perform cell balance discharge. As a result, a discharge current is generated that flows through the wiring path DR6 from the positive electrode 202b of the rechargeable battery cell 202 via the terminal B+, the resistor element R1, the resistor element R8, the switch 40, and the terminal BM to the negative electrode 202a of the rechargeable battery cell 202. The resistor element R8 is an element for adjusting (limiting) the current value of the discharge current.

[0156] <Fifth embodiment>

[0157] Fig.14 1 is a diagram showing a configuration example of a control system in a fifth embodiment, and is a diagram showing a discharge path under cell balancing control based on the discharge of a high potential side rechargeable battery cell among a plurality of rechargeable battery cells. In the fifth embodiment, the description of the same configuration as that of the above-mentioned embodiment is omitted by citing the above-mentioned description.

[0158] exist Fig.14In the control system 305 shown, the external device 140 has a current control circuit 30 that controls the current flowing through a wiring path including at least one of a plurality of internal wirings 85 and 86. The current control circuit 30 has a current source 31 connected in series with the internal wiring 86 and a switching circuit including a switch 25 connected in series with the current source 31.

[0159] Fig.14 This indicates a normal state where no abnormality of the rechargeable battery cells 201 and 202 is detected. Fig.14 In the normal state shown in FIG. 1 , the balance control circuit 33 is connected via the wiring path DR2 (see FIG. Fig.14 ) discharges the rechargeable battery cell 202, so that the cell voltage of the rechargeable battery cell 202 approaches the cell voltage of the rechargeable battery cell 201.

[0160] Fig.14 The figure shows a case where the cell voltage of the rechargeable battery cell 202 is higher than the cell voltage of the rechargeable battery cell 201 in a normal state. When the balance control circuit 33 determines that the cell voltage of the rechargeable battery cell 202 is higher than the cell voltage of the rechargeable battery cell 201, the switch 25 is switched to the on state in order to reduce the cell voltage of the rechargeable battery cell 202, thereby causing the rechargeable battery cell 202 to discharge in the wiring path DR2.

[0161] <Sixth embodiment>

[0162] Fig.15 1 is a diagram showing a configuration example of a control system in a sixth embodiment, and is a diagram showing a discharge path under cell balancing control based on the discharge of a high potential side rechargeable battery cell among a plurality of rechargeable battery cells. In the sixth embodiment, the description of the same configuration as that of the above-mentioned embodiment is omitted by citing the above-mentioned description.

[0163] exist Fig.15 In the control system 306 shown, the protection IC 120 has a terminal VB2, and the substrate has a terminal BSH. The internal wiring 86 is connected between the terminal VBM2 and the terminal BS2. The terminal VBM2 is connected to the terminal BM without the resistor R2, and the terminal VBM1 is connected to the terminal BM via the resistor R2. The terminal BSH is connected to the terminal B+ (positive electrode 202b) via the resistor R6, and the terminal P+ is connected to the terminal B+ (positive electrode 202b) without the resistor R6.

[0164] The protection IC 120 measures the cell voltage of the rechargeable battery cell 201 by detecting the potential difference between the terminal VBM1 and the terminal VSS, and measures the cell voltage of the rechargeable battery cell 202 by detecting the potential difference between the terminal VBM1 and the terminal VDD. Thus, the cell voltages of the rechargeable battery cells 201 and 202 are measured in a wiring path different from the wiring path for the discharge current to flow, thereby improving the measurement accuracy.

[0165] In addition, the balance control circuit 33 measures the cell voltage of the rechargeable battery cell 202 by detecting the potential difference between the terminal BSH and the terminal BSM, and measures the total cell voltage VC of the rechargeable battery cells 201 and 202 by detecting the potential difference between the terminal BSH and the terminal BSL. Thus, the cell voltage of the rechargeable battery cell 202 and the total cell voltage VC of the rechargeable battery cells 201 and 202 are measured in a wiring path different from the wiring path for the discharge current to flow, so that the measurement accuracy is improved.

[0166] Thus, in each of the above-mentioned embodiments, the external device 140 can monitor the cell voltage of each of the plurality of rechargeable battery cells 201 and 202 by bypassing the switch circuit 13, so that the monitoring accuracy is improved. Therefore, the cell balance control is performed based on the monitoring result, so that the balance of the cell voltage of each of the plurality of rechargeable battery cells can be controlled with high accuracy. In addition, the internal switch is inserted in series into the internal wiring of the external device 140 for measuring the cell voltage of each of the plurality of rechargeable battery cells, so by disconnecting the internal switch, the overcurrent generated in the internal wiring can be cut off.

[0167] The control system, control method and rechargeable battery protection integrated circuit are described above by using the embodiments, but the present invention is not limited to the above embodiments. Various modifications and improvements such as combination and replacement of part or all of other embodiments can be realized within the scope of the present invention.

[0168] In addition, for example, the arrangement positions of the charge control transistor 11 and the discharge control transistor 12 may be interchanged with respect to the positions shown in the figure. In addition, the switch circuit 13 may be built in the protection IC 120. In addition, the charger 130 may be mounted on the substrate.

Claims

1. A control system, characterized in that: have: a plurality of rechargeable battery cells connected in series; a power path connected in series with the plurality of rechargeable battery cells; at least one switching element inserted in series into the power path; a rechargeable battery protection device for protecting the plurality of rechargeable battery cells by controlling the switch element; and an external device that controls the balance of the cell voltages of the plurality of rechargeable battery cells, The rechargeable battery protection device comprises: an abnormality detection circuit that monitors the voltage of all or each of the plurality of rechargeable battery cells to detect overcharge or overdischarge; one or more monitoring terminals arranged to monitor the potential of one or more electrodes including the electrode connected to the switching element among the electrodes of the plurality of rechargeable battery cells in a path not including the switching element; one or more internal wirings, which are interposed between the one or more electrodes and the one or more monitoring terminals; one or more internal switches, each of which is inserted in series into the one or more internal wirings and cuts off the current flowing through the internal wirings when the abnormality detection circuit detects an overcharge or overdischarge; as well as a switch control circuit, which turns on or off the internal switch according to the abnormality detection result of the abnormality detection circuit, The external device has: A balance control circuit controls the current flowing through a wiring path including at least one of the one or more internal wirings according to the potential of the one or more monitoring terminals when the internal switch is turned on, thereby controlling the balance of the cell voltages of the plurality of rechargeable battery cells.

2. The control system according to claim 1, characterized in that: The rechargeable battery protection device comprises: a current detection circuit that detects the current flowing in the internal wiring under the control of the balance control circuit; and a plurality of discharge circuits that are respectively provided for the plurality of rechargeable battery cells. The plurality of discharge circuits discharge corresponding rechargeable battery cells among the plurality of rechargeable battery cells according to the current detection result of the current detection circuit.

3. The control system according to claim 2, characterized in that: The current detection circuit includes a resistance element connected in series with the internal wiring, The plurality of discharge circuits each include a transistor configured to discharge a corresponding rechargeable battery cell among the plurality of rechargeable battery cells according to a voltage drop generated in the resistance element.

4. The control system according to any one of claims 1 to 3, characterized in that: The control system comprises: a current control circuit for controlling the current flowing through the wiring path; The balance control circuit controls the balance of the cell voltages of the plurality of rechargeable battery cells by controlling the current control circuit.

5. The control system according to claim 4, characterized in that: The current control circuit includes: a switching circuit that switches the wiring path between conduction and non-conduction, The balance control circuit controls the balance of the cell voltages of the plurality of rechargeable battery cells by controlling the switching circuit.

6. The control system according to claim 5, characterized in that: The switching circuit includes a plurality of switches connected in parallel with corresponding rechargeable battery cells among the plurality of rechargeable battery cells.

7. The control system according to claim 4, characterized in that: The current control circuit includes: a plurality of current sources connected in parallel with corresponding rechargeable battery cells among the plurality of rechargeable battery cells; and a plurality of switches connected in series with corresponding current sources among the plurality of current sources. The balance control circuit controls the balance of the cell voltages of the plurality of rechargeable battery cells by controlling the plurality of current sources and the plurality of switches.

8. The control system according to any one of claims 1 to 3, characterized in that: The plurality of rechargeable battery cells include: a first rechargeable battery cell having a first positive electrode and a first negative electrode having the lowest potential among the negative electrodes of the plurality of rechargeable battery cells; and a second rechargeable battery cell having a second positive electrode and a second negative electrode connected to the first positive electrode, The one or more monitoring terminals include: A monitoring terminal is provided to monitor the potential of the second cathode.

9. A control method performed by a device for monitoring the potential of one or more electrodes of a plurality of rechargeable battery cells connected in series, characterized in that: The plurality of rechargeable battery cells are protected by controlling at least one switching element inserted in series into a power supply path connected in series with the plurality of rechargeable battery cells by a rechargeable battery protection circuit. The rechargeable battery protection circuit has: an abnormality detection circuit that monitors the voltage of all or each of the plurality of rechargeable battery cells to detect overcharge or overdischarge; one or more monitoring terminals arranged to monitor the potential of the one or more electrodes including the electrode connected to the switching element among the electrodes of the plurality of rechargeable battery cells in a path not including the switching element; one or more internal wirings, which are interposed between the one or more electrodes and the one or more monitoring terminals; one or more internal switches, each of which is inserted in series into the one or more internal wirings and cuts off the current flowing through the internal wirings when the abnormality detection circuit detects an overcharge or overdischarge; as well as a switch control circuit, which turns on or off the internal switch according to the abnormality detection result of the abnormality detection circuit, The device controls the balance of the cell voltages of the plurality of rechargeable battery cells by controlling the current flowing through the wiring path including at least one of the one or more internal wirings based on the potential of the one or more monitoring terminals when the internal switch is turned on.

10. A rechargeable battery protection integrated circuit, which protects a plurality of rechargeable battery cells by controlling at least one switch element inserted in series into a power supply path connected in series with a plurality of rechargeable battery cells connected in series, characterized in that: The rechargeable battery protection integrated circuit comprises: an abnormality detection circuit that monitors the voltage of all or each of the plurality of rechargeable battery cells to detect overcharge or overdischarge; one or more monitoring terminals arranged to monitor the potential of one or more electrodes including the electrode connected to the switching element among the electrodes of the plurality of rechargeable battery cells in a path not including the switching element; one or more internal wirings, which are interposed between the one or more electrodes and the one or more monitoring terminals; one or more internal switches, each of which is inserted in series into the one or more internal wirings and cuts off the current flowing through the internal wirings when the abnormality detection circuit detects an overcharge or overdischarge; as well as a switch control circuit, which turns on or off the internal switch according to the abnormality detection result of the abnormality detection circuit, The one or more monitoring terminals output the potential of the one or more electrodes so that an external device can control the current flowing through a wiring path including at least one of the one or more internal wirings according to the potential of the one or more monitoring terminals when the internal switch is turned on, thereby being able to control the balance of the cell voltages of each of the multiple rechargeable battery cells.

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