Electric energy storage device and method for operating the same

Abstract

Provided is a battery control circuit with a novel structure, a battery protection circuit with a novel structure, and an electricity storage device including the battery circuit. Provided is an electricity storage device, including a first circuit portion, a second circuit portion, a third circuit portion, and a secondary battery, wherein the first circuit portion has a function of controlling charging of the secondary battery, the first circuit portion has a function of transmitting the start time and end time of charging of the secondary battery to the third circuit portion, the second circuit portion has a function of generating a first voltage and a first current and supplying them to the third circuit portion, the third circuit portion has a function of generating a second voltage by charging a capacitor with the first current, and the third circuit portion has a function of comparing the first voltage and the second voltage.

Description

Technical Field

[0001] One embodiment of the present invention relates to a semiconductor device and a method for operating the semiconductor device. Another embodiment of the present invention relates to a battery control circuit, a battery protection circuit, a power storage device, and an electronic device.

[0002] One embodiment of the present invention is not limited to the above-mentioned technical field. The technical field of the invention disclosed in this specification and the like relates to an object, a method or a manufacturing method. In addition, one embodiment of the present invention relates to a process, a machine, a product or a composition of matter. Therefore, specifically, as examples of the technical field of one embodiment of the present invention disclosed in this specification, a display device, a light emitting device, a power storage device, a camera device, a storage device, a driving method of these devices or a manufacturing method of these devices can be cited. Background Art

[0003] Power storage devices (also referred to as batteries or secondary batteries) are used in various fields such as small electronic devices and automobiles. As the application range of batteries expands, the application of battery stacks using a multi-cell structure in which a plurality of battery cells are connected in series is increasing.

[0004] The power storage device is equipped with a circuit for detecting abnormalities during charging and discharging, such as over-discharging, over-charging, over-current, or short circuit. In this way, in the circuit for protecting and controlling the battery, data such as voltage or current are acquired in order to detect abnormalities during charging and discharging. In addition, in this circuit, charging and discharging are stopped or cell balancing is performed based on the observed data.

[0005] Patent Document 1 discloses a protection IC used as a battery protection circuit. The protection IC described in Patent Document 1 has a structure in which a plurality of comparators are provided inside the protection IC and compares a reference voltage with a voltage of a terminal connected to a battery to detect abnormalities during charging and discharging.

[0006] Patent Document 2 discloses a battery state detection device for detecting a micro short circuit of a secondary battery and a battery pack incorporating the same.

[0007] Patent Document 3 discloses a protective semiconductor device for protecting a battery pack including secondary battery cells connected in series.

[0008] [Prior technical literature]

[0009] [Patent Document]

[0010] [Patent Document 1] U.S. Patent Application Publication No. 2011-267726

[0011] [Patent Document 2] Japanese Patent Application Publication No. 2010-66161

[0012] [Patent Document 3] Japanese Patent Application Publication No. 2010-220389 Summary of the invention

[0013] Technical problem to be solved by the invention

[0014] The power storage device according to one embodiment of the present invention preferably detects a micro short circuit or a sign of a micro short circuit to improve the safety of the secondary battery.

[0015] Micro short circuit refers to a very small short circuit inside a secondary battery. It is not a state in which charging and discharging cannot be performed due to a short circuit between the positive and negative electrodes of the secondary battery, but a phenomenon in which a short circuit current flows for a short time in a very small short circuit portion. The cause of the micro short circuit is estimated to be that metal elements such as lithium or cobalt are precipitated inside the battery due to deterioration caused by repeated charging and discharging, and the precipitate grows and local current concentration occurs in a part of the positive electrode and a part of the negative electrode, thereby causing a part of the separator to not work or produce side reaction products.

[0016] In order to achieve miniaturization of the secondary battery, the separator needs to be thinned, and charging with high-speed power supply at a high voltage is required. In the above structure, the secondary battery is prone to micro short circuit.

[0017] Traditionally, the designer of the equipment has set the upper and lower voltage limits of the secondary battery used to control the upper limit of the external output current. The range of the voltage above the lower voltage limit and below the upper voltage limit of the secondary battery is within the recommended voltage range, and the protection circuit does not perform abnormal detection such as micro short circuits that occur within the range. Therefore, due to the repeated occurrence of large currents flowing instantaneously due to micro short circuits, major accidents such as abnormal heating and ignition of the secondary battery may occur. Therefore, it is preferred to detect micro short circuits early. In addition, in order to reduce this risk, there is a need to control the charge and discharge of the battery.

[0018] One of the purposes of one embodiment of the present invention is to provide a novel battery control circuit, a novel battery protection circuit, a power storage device, an electronic device, etc. Another purpose of one embodiment of the present invention is to achieve a reduction in power consumption. Another purpose of one embodiment of the present invention is to provide a battery control circuit, a battery protection circuit, a power storage device, an electronic device, etc. having a novel structure.

[0019] Another object of one embodiment of the present invention is to provide a power storage device that detects a micro short circuit or a sign of a micro short circuit in a secondary battery and has high safety.

[0020] Note that the purpose of one embodiment of the present invention is not limited to the above-mentioned purpose. The above-mentioned purposes do not prevent the existence of other purposes. In addition, other purposes are purposes that are not mentioned above but will be described in the following description. Those skilled in the art can derive and appropriately extract the purposes not mentioned above from the description of the specification or drawings, etc. Note that one embodiment of the present invention achieves at least one of the above-mentioned purposes and / or other purposes.

[0021] Solutions to technical problems

[0022] (1) One embodiment of the present invention is a power storage device comprising: a first circuit unit; a second circuit unit; a third circuit unit including a comparator and a capacitor; and a secondary battery, wherein the first circuit unit has a function of controlling the charging of the secondary battery, the first circuit unit has a function of transmitting the start of charging of the secondary battery to the third circuit unit, the second circuit unit has a function of generating a first voltage and a first current and supplying them to the third circuit unit, the third circuit unit has a function of generating a second voltage by charging the capacitor with the first current, and the comparator has a function of comparing the first voltage and the second voltage.

[0023] (2) In the power storage device having the configuration of (1) above, it is preferable that the second circuit unit converts the digital signal supplied from the first circuit unit to generate the first voltage, and the first voltage is an analog signal.

[0024] (3) In addition, in the power storage device of the structure of (1) or (2) above, it is preferred that the third circuit unit includes a transistor, the channel formation region of the transistor contains indium, zinc and element M, the element M is one or more of aluminum, gallium, yttrium, copper, vanadium, beryllium, boron, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten and magnesium, one of the non-inverting input terminal and the inverting input terminal of the comparator is electrically connected to an electrode in the capacitor, the other of the non-inverting input terminal and the inverting input terminal of the comparator is electrically connected to one of the source and the drain of the transistor, and has a function of maintaining a first voltage at one of the source and the drain of the transistor by putting the transistor in an off state.

[0025] (4) In addition, in the power storage device having the structure of (1), (2) or (3) above, preferably, the third circuit unit includes a second transistor, a channel formation region of the second transistor contains indium, zinc and element M, element M is one or more elements selected from the group consisting of aluminum, gallium, yttrium, copper, vanadium, beryllium, boron, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten and magnesium, and one of the source and drain of the second transistor is electrically connected to an electrode of the capacitor.

[0026] (5) In addition, one embodiment of the present invention is a method for operating a power storage device, which includes: a first circuit unit; a second circuit unit; a third circuit unit; and a secondary battery, the first circuit unit having a function of controlling the charging of the secondary battery, the method for operating the power storage device including a first step of generating a first voltage and a first current in the second circuit unit; a second step of supplying the first voltage and the first current to the third circuit unit; a third step of supplying current to the secondary battery and starting charging; a fourth step of supplying a first signal for transmitting the start of charging from the first circuit unit to the third circuit unit; a fifth step of generating a second voltage corresponding to the time elapsed from the start of charging in the third circuit unit; and a sixth step of comparing the first voltage and the second voltage.

[0027] (6) In addition, in the power storage device of (5) above, it is preferred that the third circuit unit includes a capacitor, and in the fifth step, the third circuit unit charges the capacitor with an amount of charge equivalent to the product of the first current and the elapsed time, and obtains the potential difference between the electrodes at both ends of the capacitor as the second voltage.

[0028] (7) In addition, according to the first step of the operating method of (5) or (6) above, it is preferable that the second circuit unit converts the digital signal supplied from the first circuit unit and generates a first voltage, and the first voltage is an analog signal.

[0029] (8) In addition, according to the working method of (5), (6) or (7) above, preferably, the third circuit unit includes a comparator and a transistor, one of the non-inverting input terminal and the inverting input terminal of the comparator is electrically connected to one of the source and the drain of the transistor, in the second step, a first voltage is supplied to one of the non-inverting input terminal and the inverting input terminal of the comparator, in the third step to the sixth step, the first voltage supplied to one of the non-inverting input terminal and the inverting input terminal of the comparator is maintained by turning off the transistor, and in the fifth step, a second voltage is supplied to the other of the non-inverting input terminal and the inverting input terminal of the comparator.

[0030] (9) In addition, according to the working method of (5), (6), (7) or (8) above, preferably, the third circuit unit includes a capacitor, charging of the first current of the capacitor is started according to the first signal, and the second voltage corresponds to the potential difference between the two ends of the capacitor.

[0031] (10) Alternatively, one embodiment of the present invention is a method for operating an electric storage device, the electric storage device comprising: a first circuit unit; a second circuit unit; a third circuit unit; a temperature sensor; and a secondary battery, the first circuit unit comprising an operation circuit and a memory, the first circuit unit having a function of controlling the charging of the secondary battery, the electric storage device further comprising: a first step of supplying current to the secondary battery and starting a first charge at a first moment; a second step of ending the first charge at a second moment; a third step of supplying the temperature measured by the temperature sensor, the first moment, and the second moment to the memory; a fourth step of determining the magnitude of a first voltage by performing an operation through an operation circuit in the first circuit unit using the temperature, the first moment, and the second moment stored in the memory; a fifth step of generating a first voltage and a first current of magnitudes determined by operation in the second circuit unit; a sixth step of supplying the first voltage and the first current to the third circuit unit; a seventh step of supplying current to the secondary battery and starting a second charge; an eighth step of supplying a first signal for transmitting the start of the second charge from the first circuit unit to the third circuit unit; a ninth step of generating a second voltage corresponding to the elapsed time from the start of the charge in the third circuit unit; and a tenth step of comparing the first voltage and the second voltage, the first charge being CC charge and the second charge being CV charge.

[0032] In addition, according to the working method of (10) above, preferably, the third circuit unit includes a capacitor, and in the eighth step, the third circuit unit charges the capacitor with an amount of charge equivalent to the product of the first current and the elapsed time, and obtains the potential difference between the electrodes at both ends of the capacitor as the second voltage.

[0033] (12) In addition, according to the working method of (10) or (11) above, preferably, in the fifth step, the second circuit unit converts the digital signal supplied from the first circuit unit and generates a first voltage, and the first voltage is an analog signal.

[0034] In addition, according to the working method of (10), (11) or (12), preferably, the third circuit unit includes a comparator and a transistor, one of the non-inverting input terminal and the inverting input terminal of the comparator is electrically connected to one of the source and the drain of the transistor, in the sixth step, a first voltage is supplied to one of the non-inverting input terminal and the inverting input terminal of the comparator, in the sixth step to the tenth step, the first voltage supplied to one of the non-inverting input terminal and the inverting input terminal of the comparator is maintained by turning off the transistor, and in the ninth step, a second voltage is supplied to the other of the non-inverting input terminal and the inverting input terminal of the comparator.

[0035] Effects of the Invention

[0036] One embodiment of the present invention can provide a novel battery control circuit, a novel battery protection circuit, a power storage device, an electronic device, etc. In addition, one embodiment of the present invention can achieve a reduction in power consumption. In addition, one embodiment of the present invention can provide a battery control circuit, a battery protection circuit, a power storage device, an electronic device, etc. with a novel structure.

[0037] In addition, one embodiment of the present invention can provide a power storage device that detects a micro short circuit or a sign of a micro short circuit in a secondary battery and has high safety.

[0038] Note that the effects of one embodiment of the present invention are not limited to the effects listed above. The effects listed above do not prevent the existence of other effects. Other effects are the effects that are not described in this section and are recorded below. Those skilled in the art can derive and appropriately extract the effects that are not described in this section from the description of the specification or drawings, etc. Note that one embodiment of the present invention has at least one of the effects listed above and / or other effects. Therefore, one embodiment of the present invention sometimes does not have the effects listed above.

[0039] BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a block diagram illustrating one embodiment of the present invention.

[0041] Figure 2A This is a circuit diagram illustrating one embodiment of the present invention. Figure 2B This is a circuit diagram illustrating one embodiment of the present invention.

[0042] Figure 3 This is a flowchart showing an example of the operation of one embodiment of the present invention.

[0043] Figure 4A This is a timing chart showing an operation example of one embodiment of the present invention. Figure 4B This is a timing chart showing an operation example of one embodiment of the present invention.

[0044] Figure 5A This is a circuit diagram illustrating one embodiment of the present invention. Figure 5B This is a timing chart showing an operation example of one embodiment of the present invention.

[0045] Fig. 6A This is a circuit diagram illustrating one embodiment of the present invention. Figure 6B This is a circuit diagram illustrating one embodiment of the present invention.

[0046] Figure 7 This is a circuit diagram illustrating one embodiment of the present invention.

[0047] Fig. 8A This is a circuit diagram illustrating one embodiment of the present invention. Figure 8BThis is a circuit diagram illustrating one embodiment of the present invention.

[0048] Fig. 9 This is a circuit diagram illustrating one embodiment of the present invention.

[0049] Fig.10 This is a block diagram illustrating one embodiment of the present invention.

[0050] Fig.11A It is a diagram for explaining a charging method of a secondary battery. Fig. 11B It is a diagram for explaining a charging method of a secondary battery. Fig. 11C It is a diagram showing an example of the secondary battery voltage and the charging current.

[0051] Fig. 12A It is a diagram for explaining a charging method of a secondary battery. Fig. 12B It is a diagram for explaining a charging method of a secondary battery. Fig. 12C It is a diagram for explaining a charging method of a secondary battery.

[0052] Fig.13A It is a diagram showing an example of the secondary battery voltage and the charging current. Fig. 13B It is a diagram showing an example of the secondary battery voltage and the discharge current.

[0053] Fig.14 is a cross-sectional view showing a structural example of a semiconductor device.

[0054] Fig.15 is a cross-sectional view showing a structural example of a semiconductor device.

[0055] Fig.16A is a cross-sectional view showing a structural example of a transistor. Fig. 16B is a cross-sectional view showing a structural example of a transistor. Fig. 16C is a cross-sectional view showing a structural example of a transistor.

[0056] Fig.17A is a block diagram showing a structural example of a memory. Fig. 17B is a diagram showing an example of a storage unit.

[0057] Fig.18A is a diagram showing a structural example of a memory cell array. Fig.18B is a diagram showing an example of a storage unit. Fig. 18C is a diagram showing an example of a storage unit.

[0058] Fig.19A is a diagram showing an example of a storage unit. Fig.19B is a diagram showing a structural example of a memory.

[0059] Fig. 20AIt is a flowchart showing the manufacturing process of an electronic component. Fig. 20B It is a perspective schematic diagram of electronic components.

[0060] Fig.21A is a diagram showing an example of a secondary battery. Fig. 21B is a cross-sectional view showing an example of a secondary battery. Fig. 21C is a diagram showing an example of a power storage system. Fig.21D is a diagram showing an example of a power storage system.

[0061] Fig.22A FIG. 1 is a diagram showing an example of the appearance of a secondary battery pack. Fig. 22B It is a diagram for explaining an example of the structure of a secondary battery pack. Fig. 22C It is a diagram for explaining an example of the structure of a secondary battery pack.

[0062] Fig.23A It is a diagram for explaining a vehicle according to one embodiment of the present invention. Fig. 23B It is a diagram for explaining a vehicle according to one embodiment of the present invention. Fig.23C It is a diagram for explaining a vehicle according to one embodiment of the present invention.

[0063] Fig.24A It is a diagram for explaining an electronic device according to one embodiment of the present invention. Fig. 24B This is a diagram showing an example of a power storage system according to one embodiment of the present invention.

[0064] Fig.25A It is a diagram for explaining an electronic device according to one embodiment of the present invention. Fig.25B It is a diagram for explaining an electronic device according to one embodiment of the present invention. Fig.25C It is a diagram for explaining an electronic device according to one embodiment of the present invention.

[0065] Fig.26 It is a diagram for explaining an electronic device according to one embodiment of the present invention.

[0066] Fig.27A It is a diagram for explaining an electronic device according to one embodiment of the present invention. Fig.27B It is a diagram for explaining an electronic device according to one embodiment of the present invention. Fig.27C It is a diagram for explaining an electronic device according to one embodiment of the present invention. Fig.27D It is a diagram for explaining an electronic device according to one embodiment of the present invention. Fig.27E It is a diagram for explaining an electronic device according to one embodiment of the present invention.

[0067] Fig.28 This is a diagram that illustrates the market image.

[0068] Fig.29A It is a graph showing the charging time of the secondary battery. Fig.29BIt is a graph showing the charging time of the secondary battery.

[0069] Fig. 30A It is a graph showing the charging time of the secondary battery. Fig. 30B It is a graph showing the charging time of the secondary battery.

[0070] Fig.31A It is the charging curve of the secondary battery. Fig.31B It is the charging curve of the secondary battery. Fig. 31C It is the charging curve of the secondary battery.

[0071] Fig.32 It is a graph showing the charging time of the secondary battery.

[0072] Modes for Carrying Out the Invention

[0073] The following describes the embodiments with reference to the accompanying drawings. However, the embodiments can be implemented in a number of different ways, and a person skilled in the art can easily understand that the methods and details can be transformed into various forms without departing from the purpose and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the contents described in the embodiments shown below.

[0074] Note that in this specification, etc., ordinal numbers such as "first", "second", and "third" are added to avoid confusion among constituent elements. Therefore, the ordinal numbers do not limit the number of constituent elements. In addition, the ordinal numbers do not limit the order of the constituent elements. In addition, for example, in this specification, etc., the constituent element referred to as "first" in one embodiment may be set as the constituent element referred to as "second" in other embodiments or within the scope of the claims. In addition, for example, in this specification, etc., the constituent element referred to as "first" in one embodiment may be omitted in other embodiments or within the scope of the claims.

[0075] In the drawings, the same reference numerals may be used to indicate the same components, components having the same functions, components formed of the same material, components formed at the same time, etc., and repeated descriptions may be omitted.

[0076] (Implementation Method 1)

[0077] In this embodiment, an example of a power storage device which is one embodiment of the present invention is described.

[0078] Figure 1 The power storage device 100 shown includes a control circuit 101 , a reference generation circuit 102 , a timer circuit 103 , a regulator 104 , a power source 105 , a resistor 131 , and a secondary battery 121 .

[0079] The control circuit 101 supplies a signal to the reference generation circuit 102 and the timer circuit 103. The control circuit 101 also has a function of charging the secondary battery 121.

[0080] The resistor 131 is electrically connected in series with the secondary battery 121. The control circuit 101 is preferably electrically connected to both ends of the resistor 131. The control circuit 101 has a function of measuring the current flowing through the resistor 131. For example, the current flowing through the resistor 131 and the current flowing through the secondary battery 121 are substantially the same.

[0081] The reference generation circuit 102 supplies a reference voltage and a reference current (Vref, Iref (Digital)) to the timer circuit 103 based on the signal supplied from the control circuit 101. In addition, the reference generation circuit 102 has a function of converting the supplied digital signal into an analog signal. When the control circuit 101 supplies a signal such as a reference voltage and a reference current as a digital signal, it can be converted into an analog signal and supplied to the timer circuit 103.

[0082] The timer circuit 103 has a function of measuring or monitoring the constant current charging time and the constant voltage charging time of the secondary battery 121 based on the supplied reference voltage and reference current (Vref, Iref (Analog)). The timer circuit 103 can generate the current Iss1, the current Iss2, and the current Iss3 described below using the current Iref provided by the reference generation circuit 102.

[0083] The timer circuit 103 has a function of holding a supplied analog signal, a function of comparing two or more supplied analog signals, and a function of calculating a time corresponding to a supplied analog signal.

[0084] Figure 2A and Figure 2B An example of the configuration of the timer circuit 103 is shown. Figure 2A The timer circuit 103 shown includes a current supply unit 191, a capacitor 161, and a comparator 164. The current supply unit 191 includes a switch 162 and a constant current source 163. One electrode of the switch 162 is electrically connected to the ground potential, and one electrode of the constant current source 163 is electrically connected to the high potential signal Vdd. The non-inverting input terminal of the comparator 164 is referred to as the terminal IN1, and the output terminal is referred to as the terminal OUT. Figure 2A In the embodiment, the terminal IN1 is electrically connected to one electrode of the capacitor 161, the other electrode of the switch 162, and the other electrode of the constant current source 163. In addition, the other electrode of the capacitor 161 is electrically connected to the ground potential. Note that in this embodiment, a low potential signal may be used instead of the ground potential.

[0085] Sometimes Figure 2A The current source shown is called a sourcing current source.

[0086] Figure 1 , Figure 2A and Figure 2B The timer circuit 103 shown preferably includes an OS transistor. The OS transistor will be described below. Since the timer circuit 103 includes an OS transistor, the supplied analog signal can be held. The timer circuit 103 has a function of holding a signal and can perform power gating. The signal PG used for power gating is supplied from the control circuit 101 to the reference generation circuit 102.

[0087] Figure 2B An example of the structure of the timer circuit 103 capable of power gating is shown. Figure 2B The timer circuit 103 shown is Figure 2A The difference is Figure 2B The timer circuit 103 shown in FIG. 1 includes a storage element 159. The inverting input terminal of the comparator 164 is connected to one of the source and the drain of the transistor 165. The storage element 159 includes the transistor 165 and the capacitor 160. Figure 2B One of the source and drain of the transistor 165 in is called a node ND. By making the transistor 165 an OS transistor and making the transistor 165 in an off state, the potential supplied to the inverting input terminal can be stored in the node ND for a long time. The node ND is preferably electrically connected to one electrode in the capacitor 160. The other electrode in the capacitor 160 is connected to the ground potential, for example. During the period when the transistor 165 is in the off state, no signal can be supplied from the reference generation circuit 102 to the timer circuit 103. Therefore, during this period, it is preferred to supply the signal PG to the reference generation circuit 102 and perform operations based on the supplied signal. The signal PG is supplied by the reference generation circuit 102, for example, the power supply of the reference generation circuit 102 is cut off. Alternatively, the power supply of a part of the reference generation circuit 102 is cut off. Alternatively, at least a part of the voltage supplied to the reference generation circuit 102 is set to a low potential signal, for example, a ground signal. Due to power gating, the current consumption of the reference generation circuit 102 can be extremely small.

[0088] Sometimes Figure 2B The current source shown is called a sourcing current source.

[0089] The following will explain Figure 1 Regulator 104 is shown.

[0090] In addition, in this specification, etc., a battery control circuit of one embodiment of the present invention or a power storage device including the battery control circuit is sometimes referred to as a BTOS (Battery operating system; Battery operating system, or Battery oxide semiconductor; Battery oxide semiconductor). BTOS can sometimes build a system with low power consumption. BTOS can sometimes build a system with a simple circuit.

[0091] <Charging time>

[0092] The power storage device according to one embodiment of the present invention preferably detects a micro short circuit or a sign of a micro short circuit to improve the safety of the secondary battery.

[0093] The inventors have found that the charging time becomes longer before the phenomenon of predicted micro-short circuit is observed during the charging of a secondary battery, etc. An example of the phenomenon of predicted micro-short circuit can be a sharp drop in charging voltage. "Before the phenomenon of predicted micro-short circuit is observed" refers to, for example, at least one of the charging of the last cycle of charging for predicted micro-short circuit or the charging between the last three cycles and the last cycle. "Longer charging time" refers to, for example, a longer charging time than the charging time after the shipment of a secondary battery or a storage device or the last ten cycles or more.

[0094] Note that the charging time depends on the temperature of the secondary battery (for example, the temperature of a temperature sensor included in the secondary battery) and degradation caused by the use of the secondary battery. However, if the charging time unexpectedly becomes longer by considering the cause of the change, it can be determined that a micro short circuit has occurred.

[0095] Therefore, when the charging time of the secondary battery is monitored and the charging time is longer than the specified time, micro short circuits can be suppressed and the safety of the secondary battery can be improved by, for example, stopping the operation of the secondary battery or limiting the operation of the secondary battery, more specifically, by, for example, narrowing the voltage range of the secondary battery.

[0096] The relationship between micro short circuit and charging time can be considered as follows. When a micro short circuit occurs, the voltage during charging is not easy to rise and the constant current (CC) charging time becomes longer. In addition, during constant voltage (CV) charging, it can be estimated that the time for the charging current to reach the lower limit becomes longer due to the flow of short circuit current.

[0097] Compared with CC charging, CV charging is sometimes more significantly affected by micro-short circuits.

[0098] In addition to detecting micro short circuits, a power storage device according to one embodiment of the present invention can also evaluate the SOH (State of Health, hereinafter also referred to as the health state) of a secondary battery. In the SOH, when the new state of the secondary battery is 100, the SOH of the secondary battery becomes less than 100 as the secondary battery deteriorates. As the secondary battery deteriorates, the CV charging time sometimes becomes longer. For example, the SOH can be calculated by observing the charging time and comparing it with the data stored in a table.

[0099] Next, CC charging and CV charging will be described.

[0100] [Charge and discharge method]

[0101] The charging and discharging of the secondary battery can be performed, for example, as follows.

[0102] First, CC charging is described as one of the charging methods. CC charging is a charging method in which a constant current flows through the secondary battery throughout the charging period and charging is stopped when the voltage of the secondary battery reaches a predetermined voltage. Fig.11A As shown in the figure, the secondary battery is assumed to be an equivalent circuit of internal resistance R and secondary battery capacity C. In this case, the secondary battery voltage V B is the voltage V applied to the internal resistor R R and the voltage V applied to the secondary battery capacity C C The sum of .

[0103] During CC charging, if Fig.11A As shown, the switch is turned on and a constant current I flows through the secondary battery. During this period, since the current I is constant, the voltage V applied to the internal resistor R R According to V R =R×I is constant according to Ohm's law. On the other hand, the voltage V applied to the secondary battery capacity C is C As time goes by, the secondary battery voltage V B Rising over time.

[0104] And, when the secondary battery voltage V B When the voltage reaches a specified value, such as 4.3V, charging is stopped. Fig. 11B As shown, the switch is closed and the current I = 0. Therefore, the voltage V applied to the internal resistor R R Therefore, the secondary battery voltage V B decline.

[0105] Fig. 11C The secondary battery voltage V during CC charging and after CC charging is stopped is shown. B With charging current example. Fig. 11C It can be seen that the secondary battery voltage V B It decreases slightly after CC charging is stopped.

[0106] Next, a charging method different from the above, namely CCCV charging, is described. CCCV charging is a charging method in which CC charging is first performed to a predetermined voltage, and then CV charging is performed until the flowing current decreases, specifically, until the end current value is reached.

[0107] During CC charging, if Fig. 12A As shown in the figure, the switch of the constant current power supply is turned on and the switch of the constant voltage power supply is turned off, so a constant current I flows through the secondary battery. During this period, because the current I is constant, the voltage V applied to the internal resistor R is R According to V R =R×I is constant according to Ohm's law. On the other hand, the voltage V applied to the secondary battery capacity C is C As time goes by, the secondary battery voltage V B Rising over time.

[0108] And, when the secondary battery voltage V B When the voltage reaches a specified value, for example, 4.3V, the battery switches from CC charging to CV charging. Fig. 12B As shown in the figure, the switch of the constant current power supply is turned on and the switch of the constant voltage power supply is turned off, so the secondary battery voltage V B On the other hand, the voltage V applied to the secondary battery capacity C is constant. C As time goes by, it increases. Because V B =V R +V C , so the voltage V applied to the internal resistor R R As time goes by, the voltage V applied to the internal resistor R R becomes smaller, and the current I flowing through the secondary battery changes according to V R =R×I and becomes smaller according to Ohm's law.

[0109] Then, when the current I flowing through the secondary battery reaches a predetermined current, for example, a current equivalent to 0.01C, charging is stopped. Fig. 12C As shown, all switches are closed, and the current I = 0. Therefore, the voltage V applied to the internal resistor R R However, the voltage V applied to the internal resistor R is sufficiently reduced by CV charging. R , so even if the voltage of the internal resistor R does not drop, the secondary battery voltage V B It hardly drops.

[0110] Fig.13A The secondary battery voltage V during CCCV charging and after CCCV charging is stopped is shown. B With charging current example. Fig.13A It can be seen that the secondary battery voltage V B Even after CCCV charging is stopped, there is almost no drop.

[0111] Next, CC discharge, which is one of the discharge methods, is described. CC discharge is a method in which a constant current is discharged from a secondary battery during the entire discharge period and a voltage V B A discharge method in which the discharge is stopped when a predetermined voltage, such as 2.5V, is reached.

[0112] Fig. 13B The secondary battery voltage V during CC discharge is shown B Example with discharge current. Fig. 13B It can be seen that the secondary battery voltage V B Decreases as discharge progresses.

[0113] Here, the discharge rate and the charge rate are explained. The discharge rate refers to the ratio of the current during discharge to the battery capacity, and is represented by the unit C. In a battery with a rated capacity of X (Ah), the current equivalent to 1C is X (A). In the case of discharging with a current of 2X (A), it can be said to be discharged at 2C, and in the case of discharging with a current of X / 5 (A), it can be said to be discharged at 0.2C. In addition, the same is true for the charge rate. In the case of charging with a current of 2X (A), it can be said to be charged at 2C, and in the case of charging with a current of X / 5 (A), it can be said to be charged at 0.2C.

[0114] <Operation Example of Power Storage Device>

[0115] Figure 3 A flowchart showing an example of the operation of the power storage device according to one embodiment of the present invention. Figure 4A and Figure 4B FIG. 2 shows an example of a timing chart showing the states of the signal RESET, the terminal IN1, and the terminal OUT. Figure 4A and Figure 4B In the diagram, a high potential signal is recorded as Hi, and a low potential signal is recorded as Lo.

[0116] First, the process starts in step S000.

[0117] Next, in step S001, a charging mode is selected. For example, one of CC charging and CV charging is selected.

[0118] Next, in step S002, the reference time of charging is set. When the charging mode is CC charging, the reference time tc of constant current charging is set, and when the charging mode is CV charging, the reference time tv of constant voltage charging is set. More specifically, for example, the voltage Vref1 and the current Iss1 corresponding to the set reference time are supplied from the reference generation circuit 102 to the timer circuit 103. The voltage Vref1 is supplied to the inverting input terminal of the comparator 164, and the current Iss1 is supplied to the constant current source 163.

[0119] The voltage and current corresponding to the charging time can be obtained as follows. The capacitance value of the capacitor 161 is set to the capacitance value Ca1. The product of the current Iss1 and the time tr is equal to the product of the capacitance value Ca1 and the voltage Vref1. By using this relationship, the current Iss1 and the voltage Vref1 are determined so that the charging time tr becomes a desired value.

[0120] The reference time is, for example, a value obtained by adding a certain margin to the estimated charging time. The reference time tc and the reference time tv may be, for example, a predetermined value or a value obtained by adding a predetermined time to the charging time measured during the last charging. The reference time tc and the reference time tv may be stored in a table, for example. The table includes, for example, one or both of a volatile memory and a nonvolatile memory. As the memory, a DOSRAM, a NOSRAM, etc. described below may be used.

[0121] For example, the value of the reference time tc can be determined based on the voltage of the secondary battery at the start of charging. The voltage at the start of charging changes depending on the remaining capacity SOC (State of charge) of the secondary battery. The table preferably stores the reference time tc based on the voltage at the start of charging. As the charging start voltage, for example, the voltage after a certain time, such as a few seconds, has passed since the start of charging is cited.

[0122] For example, the charging time depends on the temperature Tb of the secondary battery, so the table preferably stores reference times corresponding to the temperature. The table stores several conditions, for example, and stores reference times corresponding to three temperatures as an example, and as for reference times other than the temperature stored in the table, they can be obtained by the operation circuit included in the control circuit 101, etc. using the values ​​stored in the table.

[0123] The dependency on the temperature Tb, the dependency on the remaining capacity SOC is set to a certain coefficient and a value obtained by multiplying the charging time measured at the last charging by the coefficient may be used as the reference time.

[0124] Alternatively, the reference time tv may be calculated using the temperature Tb and the actually measured CC charging time.

[0125] In addition, due to the internal resistance, the voltage of the secondary battery sometimes rises (or falls). The amount of voltage rise (or fall) depends on the internal resistance and the current density. By using the open circuit voltage (OCV) as the voltage of the secondary battery, the influence of the internal resistance can sometimes be suppressed. Therefore, OCV can be used as the voltage at the start of charging of the secondary battery. Alternatively, it is preferred to use the voltage at a specified current density. Alternatively, when calculating the reference time, it is preferred to consider the increase in voltage due to the current density.

[0126] Next, in step S003, a reset operation is performed ( Figure 4A and Figure 4B Specifically, the control circuit 101 supplies a signal RESET to the timer circuit 103. Figure 4A and Figure 4B As shown in FIG. 1 , a high potential signal is supplied. When the signal RESET is supplied to the timer circuit 103 , the switch 162 is turned on. When the switch 162 is turned on, the ground potential is supplied to the terminal IN.

[0127] In step S004, charging starts and the switch 162 is turned off, and the measurement of the charging time tb starts ( Figure 4A and Figure 4B At the time t2 of the charging start, for example, the signal RESET becomes low and the switch 162 becomes closed. Note that the charging time is obtained by measuring the voltage of the terminal IN1 in the timer circuit 103. That is, in step S004, the voltage of the terminal IN1 (hereinafter referred to as the voltage Vin) may be measured.

[0128] Next, in step S005, when the voltage Vin exceeds the voltage Vref1 ( Figure 4B At time t4, the process proceeds to step S006. If the voltage Vin does not exceed the voltage Vref1, the process proceeds to step S008. Here, the voltage Vin exceeding the voltage Vref1 is equivalent to the charging time being longer than the set charging reference time. If the voltage Vin exceeds the voltage Vref1, for example, a high potential signal is output from the output terminal OUT of the comparator 164. If the voltage Vin does not exceed the voltage Vref1, a signal of opposite polarity is output from the output terminal OUT of the comparator 164, for example, a low potential signal Lo.

[0129] Next, in step S006, the power storage device 100 issues a warning to the user. The warning may be displayed on a display unit included in the power storage device 100, or a warning sound may be emitted from a speaker included in the power storage device 100. Note that in step S006, the switch 162 may remain in the closed state or may be in the open state.

[0130] Alternatively, in step S006 , the power storage device 100 may stop charging the secondary battery 121 .

[0131] In step S008, it is determined whether the current charging mode is to be terminated. This determination is performed, for example, by the control circuit 101. If the current charging mode is to be terminated, the process proceeds to step S009, and if the current charging mode is not to be terminated, the process returns to step S004.

[0132] In step S009, the signal RESET is supplied from the control circuit 101 to the timer circuit 103, the switch 162 is turned on and a reset operation is performed ( Figure 4A at the moment t3).

[0133] Next, in step S010 , when charging is continued in a different charging mode, the process returns to step S002 , and when charging is not continued, the process proceeds to step S099 .

[0134] In step S099, the processing ends.

[0135] <Regulator>

[0136] like Figure 1 As shown, the power storage device 100 preferably includes a regulator 104. The regulator 104 has a function of outputting a desired voltage according to a supplied signal, for example. In addition, the regulator 104 preferably has a function of lowering or raising the supplied voltage.

[0137] right Figure 1 1. The regulator 104 shown in FIG. 1 is described. The regulator 104 is a step-down power stage. The regulator 104 includes a transistor 152, a transistor 153, and a coil 156. One of the source and drain of the transistor 152 is electrically connected to the negative electrode of the secondary battery 121 and the negative electrode of the power supply. One of the source and drain of the transistor 153 is electrically connected to the positive electrode of the power supply. The other of the source and drain of the transistor 152 is electrically connected to the other of the source and drain of the transistor 153. One electrode in the coil 156 is electrically connected to the positive electrode of the secondary battery 121 through the resistor 131. The other electrode in the coil 156 is electrically connected to the other electrode of the source and drain of the transistor 152. The gate electrodes of the transistor 152 and the transistor 153 are respectively supplied with signals from the control circuit 101.

[0138] <Example of Variation of Timer Circuit>

[0139] Refer to Figures 5 to Fig. 9 A modification example of the timer circuit 103 will be described.

[0140] Figure 5AThe timer circuit 103 shown includes a current supply unit 192 instead of Figure 2A The current supply unit 191 shown in FIG. The current supply unit 192 includes a switch 162 and a constant current source 163. One electrode of the switch 162 is electrically connected to the high potential signal Vref2, and one electrode of the constant current source 163 is electrically connected to the ground potential. Another electrode of the switch 162 and another electrode of the constant current source 163 are electrically connected to one electrode of the capacitor 161. Figure 5A In FIG. 1 , one electrode of the capacitor 161 is electrically connected to a terminal IN2 used as an inverting input terminal of a comparator 164. A voltage Vref11 is supplied to a non-inverting input terminal of the comparator 164 through a storage element 159.

[0141] exist Figure 5B Shown in Figure 5A FIG. 1 is an example of a timing diagram of the states of the signal RESET, the terminal IN2, and the terminal OUT in the timer circuit 103 shown in FIG. 1 . At time t1, the signal RESET is supplied to the switch 162 and the high potential signal Vref2 is supplied to the terminal IN2. At time t2, charging starts. Figure 5A In the timer circuit 103 shown, as current flows through the constant current source 163, the voltage of the terminal IN2 gradually decreases.

[0142] At time t4, when the voltage of terminal IN2 is lower than voltage Vref11, that is, when the charging time is longer than the reference time for charging, a high potential signal is output from terminal OUT. Figure 5B In the figure, a high potential signal is recorded as Hi and a low potential signal is recorded as Lo.

[0143] Fig. 6A The timer circuit 103 shown in FIG. Figure 2A The timer circuit 103 shown also includes a counter 106. The counter 106 is supplied with a signal RESET, and the count is reset due to the signal RESET, for example. The terminal OUT of the comparator 164 is input to the counter 106. When the counter 106 is supplied with a signal (for example, a high potential signal) from the terminal OUT, the count of the counter 106 is increased by 1 (counting up). In addition, due to the high potential signal from the terminal OUT, the switch 166 becomes an open state and the voltage of the capacitor 161 becomes a ground potential. The timer circuit 103 includes a counter 106, and a count corresponding to the charging time of the secondary battery can be output from the terminal OUT2 used as the output terminal of the timer circuit 103.

[0144] Figure 6B The timer circuit 103 shown has a current supply unit 192 instead of Fig. 6A The structure of the current supply unit 191 in the timer circuit 103 is shown.

[0145] Figure 7 The illustrated timer circuit 103 includes a current supply unit 193 , a capacitor 161 , a comparator 171 , a comparator 172 , a counter 106 , a NAND circuit 178 , and a NAND circuit 179 .

[0146] The current supply section 193 includes a switch 162, a constant current source 167, a switch 168, a switch 169, and a constant current source 170. The constant current source 167, the switch 168, the switch 169, and the constant current source 170 are electrically connected in series in the order of the constant current source 167, the switch 168, the switch 169, and the constant current source 170, and the electrode of the constant current source 167 that is not electrically connected to the switch 168 is electrically connected to the ground potential, and the electrode of the constant current source 170 that is not electrically connected to the switch 169 is electrically connected to the high potential signal Vdd. One electrode of the switch 162 is electrically connected to the high potential signal Vdd, and the other electrode of the switch 162 is electrically connected to each electrode of the switch 169, the switch 168, and the capacitor 161.

[0147] One electrode of the capacitor 161 is electrically connected to the non-inverting input terminal of the comparator 171 and the inverting input terminal of the comparator 172. The inverting input terminal of the comparator 171 is supplied with the voltage Vref1, and the non-inverting input terminal of the comparator 172 is supplied with the high potential signal Vref2. Figure 7 As shown in FIG. 1 , the voltage Vref1 and the high potential signal Vref2 can be supplied to the terminals of the comparator through the storage element 159, respectively. The output signal of the comparator 171 is supplied to the first input of the NAND circuit 178, and the output of the NAND circuit 179 is supplied to the second input. The output signal of the comparator 172 is supplied to the first input of the NAND circuit 179, and the output of the NAND circuit 178 is supplied to the second input. The output of the NAND circuit 179 is input to the counter 106. The count is output from the terminal OUT2 of the counter 106.

[0148] Figure 7 An example of the operation of the timer circuit 103 is shown. The signal QB is a signal having an inverse phase to the signal Q.

[0149] When a high potential signal is supplied as the signal RESET, the switch 162 is turned on, and the high potential signal Vdd is supplied to the capacitor 161. In addition, the counter 106 is reset by the signal RESET.

[0150] Next, a low potential signal is supplied as the RESET signal, and the switch 162 is turned off.

[0151] When the signal Q is at a high potential, the switch 168 is turned on, the switch 169 is turned off, the capacitor 161 is electrically connected to the constant current source 167, and the constant current source 167 is electrically connected to the ground potential, so that the voltage of the capacitor 161 gradually decreases. When the voltage of the capacitor 161 is lower than Vref1, a low potential signal is output from the comparator 171, and the signals Q and QB are inverted, and the signal QB becomes a high potential.

[0152] When the signal QB becomes high, the switch 169 becomes open, the switch 168 becomes closed, the capacitor 161 is electrically connected to the constant current source 170, and the constant current source 170 is electrically connected to the high potential signal Vdd, so the voltage of the capacitor 161 gradually rises. When the voltage of the capacitor 161 is higher than the high potential signal Vref2, a low potential signal is output from the comparator 172, and the signals Q and QB are inverted, and the signal Q becomes high. The signal Q supplied to the counter 106 becomes high again, so the count of the counter 106 is increased by 1.

[0153] In this way, as a current source combining a current source and a current sink, the voltage of the capacitor 161 repeatedly increases and decreases in the range of the voltage Vref1 to the high potential signal Vref2, so the signal supplied to the counter 106 repeatedly alternates between high potential and low potential and oscillates.

[0154] Fig. 8A Detailed examples are shown that can be used for the current supply section 192. The current supply section 192 includes a constant current source 173, a capacitor 174, and transistors 181 to 184. One electrode in the constant current source 173 is electrically connected to the high potential signal Vdd, the other electrode in the constant current source 173 is electrically connected to one of the source and drain and the gate of the transistor 181, the other of the source and drain of the transistor 181 is electrically connected to the ground potential, one of the source and drain of the transistor 182 is electrically connected to the gate of the transistor 181, the other of the source and drain of the transistor 182 is electrically connected to the gate of the transistor 183 and an electrode in the capacitor 174, the other electrode in the capacitor 174 is electrically connected to the ground potential, the gate of the transistor 182 and the gate of the transistor 184 are respectively supplied with the signal RESET, one of the source and drain of the transistor 183 is electrically connected to the ground potential, the other of the source and drain of the transistor 183 is electrically connected to one of the source and drain of the transistor 184 and an electrode in the capacitor 161, and the other of the source and drain of the transistor 184 is supplied with the high potential signal Vdd.

[0155] right Fig. 8A An example of the operation of the circuit shown is explained. Fig. 8AIn the case where a high potential signal is supplied as the signal RESET, the transistors 181, 182, 183, and 184 are turned on, and the current Iss1 corresponding to the current Iref flowing through the constant current source 173 flows through the transistors 183 and 184. The ratio of the current Iref to the current Iss1 changes according to the ratio of the sizes of the transistors 181 and 183 (the inverse of the channel length, the channel width, etc.). Due to the current flowing through the transistor 182, the charge is stored in the capacitor 174. Due to the current Iss1, the charge is stored in the capacitor 161.

[0156] Next, when a low potential signal is supplied as the RESET signal, the transistors 181, 182, and 184 are turned off, and a voltage corresponding to the charge stored in the capacitor 174 is applied to the gate of the transistor 183, so that the transistor 183 is turned on. The charge stored in the capacitor 161 flows through the transistor 183, and the voltage of the capacitor 161 gradually decreases.

[0157] Figure 8B Specific examples that can be used for the current supply section 191 are shown. The current supply section 191 includes a constant current source 173, a capacitor 175, a transistor 181, and transistors 185 to 190. One electrode in the constant current source 173 is supplied with a high potential signal Vdd, the other electrode in the constant current source 173 is electrically connected to one of the source and drain of the transistor 181, the gate and one of the source and drain of the transistor 185, the other of the source and drain of the transistor 185 is electrically connected to the ground potential, one of the source and drain of the transistor 186 is supplied with a high potential signal Vref3, the other of the source and drain of the transistor 186 is electrically connected to an electrode in the capacitor 175 and the gate of the transistor 188, one of the source and drain of the transistor 188 is supplied with a high potential signal Vdd, the other of the source and drain of the transistor 188 is electrically connected to one of the source and drain of the transistor 187 and one of the source and drain of the transistor 190, the other of the source and drain of the transistor 187 is electrically connected to the ground potential, the other of the source and drain of the transistor 188 is electrically connected to another electrode in the capacitor 175, and the other of the source and drain of the transistor 190 is electrically connected to an electrode in the capacitor 161. The signal RESET is supplied to the gate of the transistor 186 , and the signal RESETB is supplied to the gates of the transistor 185 and the transistor 190 .

[0158] The signal RESETB is an inverted signal of the signal RESET. The inverted signal means, for example, that when a high potential signal is output from one signal, a low potential signal is output from the other signal.

[0159] right Figure 8B An example of the operation of the circuit shown is explained. Figure 8B In the case where a high potential signal is supplied as the signal RESET, the gate of the transistor 188 is supplied with the voltage Vref3, the transistors 181, 187, and 188 are turned on, and the current Iss1 corresponding to the current Iref flowing through the constant current source 173 flows through the transistors 188 and 187. The ratio of the current Iref to the current Iss1 changes according to the ratio of the transistors 181 and 187.

[0160] Next, when a low potential signal is supplied as the signal RESET, the transistor 186 is turned off, a voltage corresponding to the charge stored in the capacitor 175 is held at the gate of the transistor 188, and the transistor 188 is turned on. In addition, the transistor 190 is turned on, and the transistor 187 is turned off. Therefore, the current Iss1 flowing through the transistor 188 is applied to the capacitor 161, and the voltage of the capacitor 161 gradually rises.

[0161] exist Fig. 8A and Figure 8B In the case where a low potential signal is supplied as the RESET signal, it is not necessary to supply current from the constant current source 173, so the constant current source 173 can be stopped. Therefore, the power supply of the reference generation circuit 102 can be gated while a low potential signal is supplied as the RESET signal.

[0162] OS transistors can reduce the off-state current, so a wide range of on-state currents from high to low can be used. Since low on-state currents can be controlled, for example, 10 -10 A / μm or less. Therefore, by Fig. 8A The transistor 183 and the transistor 184 and Figure 8B By using OS transistors for the transistors 187 and 188, the capacitance value of the capacitor 161 can be reduced, for example, the area of ​​the capacitor 161 can be reduced. Thus, the circuit can be reduced in size.

[0163] OS transistors can be used as the transistors 181 to 188 and the transistor 190 .

[0164] The threshold value of the OS transistor changes little due to temperature changes, and the OS transistor is sometimes suitably used in a device having a wide temperature range such as a secondary battery.

[0165] Fig. 9 Specific examples that can be used for the current supply unit 193 are shown. The current supply unit 193 has a combination of Fig. 8A The current supply and Figure 8BThe structure of the current supply source is shown.

[0166] In the current supply unit 193, the electrical connection of each of the constant current source 173, the transistor 181, the transistor 182, the capacitor 174, and the transistor 183 can be referred to. Fig. 8A For the electrical connection of each of transistor 186, capacitor 175, and transistor 188, please refer to Figure 8B The gate of transistor 194 is supplied with a signal RESET, one of the source and drain of transistor 194 is electrically connected to the other of the source and drain of transistor 183 and one of the source and drain of transistor 195, and the other of the source and drain of transistor 194 is electrically connected to one of the source and drain of transistor 196 and the other of the source and drain of transistor 188. The gate of transistor 195 is supplied with a signal Q, and the gate of transistor 196 is supplied with a signal QB. The gate of transistor 190 is supplied with a signal RESETB, one of the source and drain of transistor 190 is electrically connected to the other of the source and drain of transistor 195 and the other of the source and drain of transistor 196, and the other of the source and drain of transistor 190 is electrically connected to one of the source and drain of transistor 197 and one of the electrodes in capacitor 161. The other of the source and drain of transistor 197 is supplied with a voltage Vref1. The gate of transistor 197 is supplied with a signal RESET.

[0167] <Modification Example of Power Storage Device>

[0168] Fig.10 The power storage device 100 shown in the figure has Figure 1 The structure shown also includes a protection circuit 137 , a transistor 140 , and a transistor 150 .

[0169] The protection circuit 137 is preferably electrically connected to the control circuit 101 and receives signals from the control circuit 101 .

[0170] The protection circuit 137 has a function of stopping the operation of the secondary battery 121 when the secondary battery 121 meets a certain set condition. For example, when the current of the secondary battery 121 exceeds a certain value, the operation is stopped. In addition, when the voltage of the secondary battery 121 becomes higher or lower than a certain value, the operation is stopped.

[0171] The protection circuit 137 may have a path for short-circuiting both electrodes of the secondary battery 121 when stopping the operation of the secondary battery 121. This path may also be provided with a resistor or a capacitor. Fig.10The transistor 140 and the transistor 150 shown are used as switches for interrupting current, and the switches are operated when it is determined that the protection circuit 137 stops the secondary battery 121. MOSFETs having parasitic diodes can be used as the transistor 140 and the transistor 150. In addition, OS transistors can be used as the transistor 140 and the transistor 150. Alternatively, the power storage device 100 may also adopt a structure that does not include one of the transistor 140 and the transistor 150.

[0172] For example, the protection circuit 137 and the timer circuit 103 may be provided in the same chip. “In the same chip” means, for example, a structure in which two circuits are provided on the same silicon substrate or the same glass substrate.

[0173] Alternatively, for example, the protection circuit 137 and the timer circuit 103 may be provided in the same package. “In the same package” means, for example, that a chip including the protection circuit 137 and a chip including the timer circuit 103 are provided on the same printed circuit board.

[0174] This embodiment mode can be combined with the description of other embodiment modes as appropriate.

[0175] (Implementation Method 2)

[0176] A description will be given of a configuration example of a semiconductor device that can be used for the battery control circuit described in the above embodiment.

[0177] Fig.14 The semiconductor device shown includes a transistor 300 , a transistor 500 , and a capacitor 600 . Fig.16A is a cross-sectional view of the transistor 500 in the channel length direction, Fig. 16B is a cross-sectional view of the transistor 500 in the channel width direction, Fig. 16C is a cross-sectional view of the transistor 300 in the channel width direction.

[0178] The transistor 500 is an OS transistor. Since the off-state current of the transistor 500 is small, by using the transistor 500 as an OS transistor included in a semiconductor device, written data can be retained for a long period of time.

[0179] The transistor 500 is, for example, an n-channel transistor.

[0180] As a transistor included in the power storage device of one embodiment of the present invention, an OS transistor can be used. In addition, an OS transistor and a Si transistor can be used in any combination. In addition, all transistors can be OS transistors or Si transistors. As Si transistors, transistors containing amorphous silicon, transistors containing crystalline silicon (typically low-temperature polysilicon, single crystal silicon, etc.) and the like can be cited.

[0181] The OS transistor has an extremely low off-state current and has a good switching characteristic even in a high-temperature environment. Therefore, the charging or discharging of the assembled battery 120 is controlled without malfunction even in a high-temperature environment.

[0182] In addition, a memory element using an OS transistor can be freely arranged by being stacked on a circuit using a Si transistor, and can therefore be easily integrated. In addition, an OS transistor can be manufactured using the same manufacturing equipment as a Si transistor, and can be manufactured at low cost.

[0183] In addition, as an OS transistor, a semiconductor element having four terminals including a back gate electrode in addition to a gate electrode, a source electrode and a drain electrode can be used. It is composed of a circuit network that can independently control the input and output of the signal between the source and the drain according to the voltage supplied to the gate electrode or the back gate electrode. Therefore, the circuit design can be performed in the same way as LSI. Furthermore, the OS transistor has electrical characteristics superior to those of the Si transistor in a high temperature environment. Specifically, even at high temperatures such as above 100°C and below 200°C, preferably above 125°C and below 150°C, the ratio of the on-state current to the off-state current is large, so good switching operation can be performed.

[0184] like Fig.14 As shown in FIG. 1 , the semiconductor device described in this embodiment includes a transistor 300 , a transistor 500 , and a capacitor 600 . The transistor 500 is provided above the transistor 300 , and the capacitor 600 is provided above the transistor 300 and the transistor 500 .

[0185] The transistor 300 is provided on a substrate 311 and includes: a conductor 316; an insulator 315; a semiconductor region 313 formed by a portion of the substrate 311; and a low resistance region 314a and a low resistance region 314b used as a source region or a drain region. For example, the transistor 300 can be applied to the transistor included in the comparator in the above-mentioned embodiment, etc.

[0186] like Fig. 16C As shown, in the transistor 300, the conductor 316 covers the top surface and the side surface in the channel width direction of the semiconductor region 313 via the insulator 315. In this way, by making the transistor 300 have a Fin-type structure, the effective channel width is increased, thereby improving the on-state characteristics of the transistor 300. In addition, since the influence of the electric field of the gate electrode can be increased, the off-state characteristics of the transistor 300 can be improved.

[0187] In addition, transistor 300 may be a p-channel transistor or an n-channel transistor.

[0188] The channel formation region of the semiconductor region 313 or the region near it, the low resistance region 314a and the low resistance region 314b used as the source region or the drain region preferably include semiconductors such as silicon-based semiconductors, and more preferably include single crystal silicon. In addition, it can also be formed using materials including Ge (germanium), SiGe (silicon germanium), GaAs (gallium arsenide), GaAlAs (gallium aluminum arsenic), etc. Silicon that applies stress to the lattice and changes the interplanar spacing to control the effective mass can be used. In addition, the transistor 300 can also be a HEMT (High Electron Mobility Transistor) using GaAs and GaAlAs, etc.

[0189] The low resistance regions 314 a and 314 b contain, in addition to the semiconductor material used for the semiconductor region 313 , an element imparting n-type conductivity such as arsenic and phosphorus or an element imparting p-type conductivity such as boron.

[0190] As the conductor 316 used as the gate electrode, a conductive material such as a semiconductor material such as silicon, a metal material, an alloy material, or a metal oxide material containing an element imparting n-type conductivity such as arsenic and phosphorus or an element imparting p-type conductivity such as boron can be used.

[0191] In addition, since the material of the conductor determines the work function, the threshold voltage of the transistor can be adjusted by selecting the material of the conductor. Specifically, materials such as titanium nitride or tantalum nitride are preferably used as the conductor. In order to have both conductivity and embedding properties, a stack of metal materials such as tungsten or aluminum is preferably used as the conductor, and tungsten is particularly preferred in terms of heat resistance.

[0192] Notice, Fig.14 The structure of the transistor 300 shown is only an example and is not limited to the above structure. An appropriate transistor can be used according to the circuit structure or driving method. For example, when a semiconductor device is composed of only OS transistors, Fig.15 As shown in FIG. 1 , the transistor 300 may have the same structure as the transistor 500 using an oxide semiconductor. The transistor 500 will be described in detail below.

[0193] An insulator 320 , an insulator 322 , an insulator 324 , and an insulator 326 are stacked in this order so as to cover the transistor 300 .

[0194] As the insulator 320 , the insulator 322 , the insulator 324 , and the insulator 326 , for example, silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, aluminum oxide, aluminum oxynitride, aluminum nitride oxide, or aluminum nitride can be used.

[0195] Note that in this specification, silicon oxynitride refers to a material containing more oxygen than nitrogen in its composition, and silicon nitride oxide refers to a material containing more nitrogen than oxygen in its composition. Note that in this specification, aluminum oxynitride refers to a material containing more oxygen than nitrogen, and aluminum nitride oxide refers to a material containing more nitrogen than oxygen.

[0196] The insulator 322 may also be used as a planarization film for reducing step planarization caused by the transistor 300 disposed thereunder. For example, in order to improve the planarity of the top surface of the insulator 322, the top surface may be planarized by a planarization process such as chemical mechanical polishing (CMP).

[0197] As the insulator 324 , a film having a barrier property that can prevent hydrogen or impurities from diffusing from the substrate 311 , the transistor 300 , or the like into a region where the transistor 500 is provided is preferably used.

[0198] As an example of a film having a barrier property against hydrogen, for example, silicon nitride formed by a CVD method can be used. Here, hydrogen sometimes diffuses into a semiconductor element having an oxide semiconductor such as transistor 500, resulting in a decrease in the characteristics of the semiconductor element. Therefore, it is preferred to provide a film that inhibits the diffusion of hydrogen between transistor 500 and transistor 300. Specifically, the film that inhibits the diffusion of hydrogen refers to a film with a small amount of hydrogen released.

[0199] The amount of hydrogen released can be measured, for example, by thermal desorption spectroscopy (TDS). For example, when the amount of hydrogen released is converted to the amount per unit area of ​​the insulator 324 when the film surface temperature in the TDS analysis is in the range of 50°C to 500°C, the amount of hydrogen released from the insulator 324 is 10×10 15 atoms / cm 2 Below, preferably 5×10 15 atoms / cm 2 The following is enough.

[0200] Note that the dielectric constant of the insulator 326 is preferably lower than that of the insulator 324. For example, the relative dielectric constant of the insulator 326 is preferably lower than 4, more preferably lower than 3. For example, the relative dielectric constant of the insulator 326 is preferably 0.7 times or less, more preferably 0.6 times or less, the relative dielectric constant of the insulator 324. By using a material with a low dielectric constant for the interlayer film, parasitic capacitance generated between wirings can be reduced.

[0201] In addition, conductors 328 and 330 connected to capacitor 600 and transistor 500 are embedded in insulators 320, 322, 324, and 326. In addition, conductors 328 and 330 have the function of plugs or wiring. Note that the same reference numeral is sometimes used to represent a plurality of conductors having the function of plugs or wiring. In addition, in this specification, wiring and a plug connected to wiring may also be one component. That is, a part of a conductor is sometimes used as wiring, and a part of a conductor is sometimes used as a plug.

[0202] As the material of each plug and wiring (conductor 328, conductor 330, etc.), a single layer or a laminate of a conductive material such as a metal material, an alloy material, a metal nitride material, or a metal oxide material can be used. It is preferred to use a high melting point material such as tungsten or molybdenum that has both heat resistance and conductivity, and tungsten is preferably used. Alternatively, a low-resistance conductive material such as aluminum or copper is preferably used. By using a low-resistance conductive material, the wiring resistance can be reduced.

[0203] Alternatively, a wiring layer may be provided on the insulator 326 and the conductor 330. Fig.14 In the embodiment of the present invention, an insulator 350, an insulator 352, and an insulator 354 are stacked in this order. Furthermore, a conductor 356 is formed between the insulator 350, the insulator 352, and the insulator 354. The conductor 356 has a function of a plug or wiring connected to the transistor 300. The conductor 356 can be provided using the same material as the conductor 328 and the conductor 330.

[0204] In addition, similar to the insulator 324, the insulator 350 preferably uses an insulator having a barrier property to hydrogen, for example. In addition, the conductor 356 preferably includes a conductor having a barrier property to hydrogen. In particular, the conductor having a barrier property to hydrogen is formed in the opening of the insulator 350 having a barrier property to hydrogen. By adopting this structure, the transistor 300 and the transistor 500 can be separated by using a barrier layer, so that the diffusion of hydrogen from the transistor 300 to the transistor 500 can be suppressed.

[0205] Note that as a conductor having a barrier property to hydrogen, for example, tantalum nitride is preferably used. Furthermore, by stacking tantalum nitride and tungsten having high conductivity, it is possible to maintain conductivity as a wiring and suppress diffusion of hydrogen from the transistor 300. At this time, the tantalum nitride layer having a barrier property to hydrogen is preferably in contact with the insulator 350 having a barrier property to hydrogen.

[0206] Alternatively, a wiring layer may be provided on the insulator 354 and the conductor 356. Fig.14In the embodiment, an insulator 360, an insulator 362, and an insulator 364 are stacked in this order. In addition, a conductor 366 is formed in the insulator 360, the insulator 362, and the insulator 364. The conductor 366 has the function of a plug or wiring. In addition, the conductor 366 can be provided using the same material as the conductor 328 and the conductor 330.

[0207] In addition, similar to the insulator 324, the insulator 360 preferably uses an insulator having a barrier property to hydrogen. In addition, the conductor 366 preferably includes a conductor having a barrier property to hydrogen. In particular, it is preferred that a conductor having a barrier property to hydrogen is formed in an opening of the insulator 360 having a barrier property to hydrogen. By adopting this structure, the transistor 300 and the transistor 500 can be separated by using a barrier layer, thereby suppressing the diffusion of hydrogen from the transistor 300 to the transistor 500.

[0208] Alternatively, a wiring layer may be provided on the insulator 364 and the conductor 366. Fig.14 In the embodiment, an insulator 370, an insulator 372, and an insulator 374 are stacked in this order. In addition, a conductor 376 is formed in the insulator 370, the insulator 372, and the insulator 374. The conductor 376 has a function of a plug or wiring. In addition, the conductor 376 can be provided using the same material as the conductor 328 and the conductor 330.

[0209] In addition, similar to the insulator 324, the insulator 370 preferably uses an insulator having a barrier property to hydrogen. In addition, the conductor 376 preferably includes a conductor having a barrier property to hydrogen. In particular, it is preferred that a conductor having a barrier property to hydrogen is formed in an opening of the insulator 370 having a barrier property to hydrogen. By adopting this structure, the transistor 300 and the transistor 500 can be separated by using a barrier layer, thereby suppressing the diffusion of hydrogen from the transistor 300 to the transistor 500.

[0210] Alternatively, a wiring layer may be provided on the insulator 374 and the conductor 376. Fig.14 In the embodiment, an insulator 380, an insulator 382, ​​and an insulator 384 are stacked in this order. In addition, a conductor 386 is formed in the insulator 380, the insulator 382, ​​and the insulator 384. The conductor 386 has the function of a plug or wiring. In addition, the conductor 386 can be provided using the same material as the conductor 328 and the conductor 330.

[0211] In addition, similar to the insulator 324, the insulator 380 preferably uses an insulator having a barrier property to hydrogen, for example. In addition, the conductor 386 preferably includes a conductor having a barrier property to hydrogen. In particular, it is preferred that a conductor having a barrier property to hydrogen is formed in an opening of the insulator 380 having a barrier property to hydrogen. By adopting this structure, the transistor 300 and the transistor 500 can be separated by using a barrier layer, thereby suppressing the diffusion of hydrogen from the transistor 300 to the transistor 500.

[0212] In the above description, the wiring layer including the conductor 356, the wiring layer including the conductor 366, the wiring layer including the conductor 376, and the wiring layer including the conductor 386 are described, but the semiconductor device according to the present embodiment is not limited thereto. The number of wiring layers similar to the wiring layer including the conductor 356 may be three or less, and the number of wiring layers similar to the wiring layer including the conductor 356 may be five or more.

[0213] An insulator 510, an insulator 512, an insulator 514, and an insulator 516 are sequentially stacked on the insulator 384. As any one of the insulators 510, 512, 514, and 516, a substance having a barrier property against oxygen or hydrogen is preferably used.

[0214] For example, a film having a barrier property that can prevent hydrogen or impurities from diffusing from the substrate 311 or a region where the transistor 300 is provided into a region where the transistor 500 is provided is preferably used as the insulator 510 and the insulator 514. Therefore, the insulator 510 and the insulator 514 can use the same material as the insulator 324.

[0215] As an example of a film having a barrier property against hydrogen, silicon nitride formed by a CVD method can be used. Here, hydrogen sometimes diffuses into a semiconductor element having an oxide semiconductor such as transistor 500, resulting in a decrease in the characteristics of the semiconductor element. Therefore, it is preferred to provide a film that inhibits the diffusion of hydrogen between transistor 300 and transistor 500. Specifically, the film that inhibits the diffusion of hydrogen refers to a film with a small amount of hydrogen released.

[0216] For example, as a film having a barrier property against hydrogen, the insulator 510 and the insulator 514 are preferably made of a metal oxide such as aluminum oxide, hafnium oxide, or tantalum oxide.

[0217] In particular, aluminum oxide has a high barrier effect of preventing oxygen and impurities such as hydrogen and moisture that cause changes in the electrical characteristics of the transistor from penetrating. Therefore, during and after the manufacturing process of the transistor, aluminum oxide can prevent impurities such as hydrogen and moisture from entering the transistor 500. In addition, aluminum oxide can suppress the release of oxygen from the oxide constituting the transistor 500. Therefore, aluminum oxide is suitable for use as a protective film for the transistor 500.

[0218] For example, the insulator 512 and the insulator 516 can use the same material as the insulator 320. In addition, by using a material with a low dielectric constant for the insulator, the parasitic capacitance generated between wirings can be reduced. For example, the insulator 512 and the insulator 516 can use a silicon oxide film, a silicon oxynitride film, or the like.

[0219] In addition, a conductor 518 and a conductor constituting the transistor 500 (for example, the conductor 503) are embedded in the insulator 510, the insulator 512, the insulator 514, and the insulator 516. The conductor 518 is used as a plug or wiring connected to the capacitor 600 or the transistor 300. The conductor 518 can be provided using the same material as the conductor 328 and the conductor 330.

[0220] In particular, the conductor 518 in the region in contact with the insulator 510 and the insulator 514 is preferably a conductor having a barrier property to oxygen, hydrogen, and water. By adopting this structure, the transistor 300 and the transistor 500 can be separated by a layer having a barrier property to oxygen, hydrogen, and water, thereby suppressing the diffusion of hydrogen from the transistor 300 to the transistor 500.

[0221] The transistor 500 is provided above the insulator 516 .

[0222] like Fig.16A , Fig. 16B As shown, transistor 500 includes a conductor 503 configured in a manner of burying an insulator 514 and an insulator 516, an insulator 520 configured on the insulator 516 and the conductor 503, an insulator 522 configured on the insulator 520, an insulator 524 configured on the insulator 522, an oxide 530a configured on the insulator 524, an oxide 530b configured on the oxide 530a, a conductor 542a and a conductor 542b configured separately from each other on the oxide 530b, an insulator 580 configured on the conductors 542a and 542b and forming an opening in a manner overlapping between the conductors 542a and 542b, an oxide 530c configured on the bottom and side surfaces of the opening, an insulator 550 configured on the formation surface of the oxide 530c, and a conductor 560 configured on the formation surface of the insulator 550.

[0223] In addition, if Fig.16A , Fig. 16B As shown in FIG. 5 , an insulator 544 is preferably disposed between the oxide 530a, the oxide 530b, the conductor 542a, the conductor 542b, and the insulator 580. Fig.16A , Fig. 16BAs shown in FIG. 5 , the conductor 560 preferably includes a conductor 560a disposed inside the insulator 550 and a conductor 560b disposed in a manner buried inside the conductor 560a. Fig.16A and Fig. 16B As shown, an insulator 574 is preferably arranged on the insulator 580 , the conductor 560 , and the insulator 550 .

[0224] Note that below, the oxide 530 a , the oxide 530 b , and the oxide 530 c may be collectively referred to as an oxide 530 .

[0225] In transistor 500, three layers of oxide 530a, oxide 530b, and oxide 530c are stacked in the region where the channel is formed and in the vicinity thereof, but the present invention is not limited to this. For example, a single layer of oxide 530b, a two-layer structure of oxide 530b and oxide 530a, a two-layer structure of oxide 530b and oxide 530c, or a stacked structure of four or more layers may be provided. In addition, in transistor 500, conductor 560 has a two-layer structure, but the present invention is not limited to this. For example, conductor 560 may also have a single-layer structure or a stacked structure of three or more layers. Note that, Fig.14 , Fig.16A The structure of the transistor 500 shown is only an example and is not limited to the above structure, and an appropriate transistor can be used according to the circuit structure or driving method.

[0226] Here, the conductor 560 is used as the gate electrode of the transistor, and the conductor 542a and the conductor 542b are used as the source electrode or the drain electrode. As described above, the conductor 560 is arranged in a manner buried in the opening of the insulator 580 and in the area sandwiched between the conductor 542a and the conductor 542b. The configuration of the conductor 560, the conductor 542a and the conductor 542b relative to the opening of the insulator 580 is selected in a self-aligned manner. In other words, in the transistor 500, the gate electrode can be arranged in a self-aligned manner between the source electrode and the drain electrode. Thus, the conductor 560 can be formed in a manner without providing room for alignment, so that the occupied area of ​​the transistor 500 can be reduced. Thus, miniaturization and high integration of semiconductor devices can be achieved.

[0227] Furthermore, since the conductor 560 is formed in a self-aligned manner in the region between the conductor 542a and the conductor 542b, the conductor 560 does not include a region overlapping with the conductor 542a and the conductor 542b. Thus, the parasitic capacitance formed between the conductor 560 and the conductor 542a and the conductor 542b can be reduced. Therefore, the switching speed of the transistor 500 can be increased, so that the transistor 500 can have high frequency characteristics.

[0228] Conductor 560 is sometimes used as a first gate (also called a top gate) electrode. Conductor 503 is sometimes used as a second gate (also called a bottom gate) electrode. In this case, the threshold voltage of transistor 500 can be controlled by independently changing the potential supplied to conductor 503 without interlocking it with the potential supplied to conductor 560. In particular, by supplying a negative potential to conductor 503, the threshold voltage of transistor 500 can be made greater than 0V and the off-state current can be reduced. Therefore, compared to when a negative potential is not applied to conductor 503, when a negative potential is applied to conductor 503, the drain current when the potential applied to conductor 560 is 0V can be reduced.

[0229] The conductor 503 is arranged so as to overlap with the oxide 530 and the conductor 560. Thus, when a potential is supplied to the conductor 560 and the conductor 503, the electric field generated from the conductor 560 and the electric field generated from the conductor 503 are connected, and a channel formation region formed in the oxide 530 can be covered. In this specification, etc., a structure of a transistor in which a channel formation region is electrically surrounded by an electric field of a first gate electrode and an electric field of a second gate electrode is referred to as a surrounded channel (S-channel) structure.

[0230] In addition, in this specification, etc., the surrounded channel (S-channel) structure has the following characteristics, that is, the side and periphery of the oxide 530 that contacts the conductor 542a and the conductor 542b used as the source electrode and the drain electrode are I-type, as in the channel formation region. In addition, because the side and periphery of the oxide 530 that contacts the conductor 542a and the conductor 542b are in contact with the insulator 544, it is possible to become I-type, as in the channel formation region. Note that in this specification, etc., I-type can be said to be the same as the high-purity intrinsic described later. In addition, the S-channel structure disclosed in this specification, etc. is different from the Fin-type structure and the planar structure. By adopting the S-channel structure, the resistance to the short channel effect can be improved. In other words, a transistor that is not prone to the short channel effect can be realized.

[0231] In addition, the conductor 503 has the same structure as the conductor 518, and the conductor 503a is formed in contact with the inner wall of the opening of the insulator 514 and the insulator 516, and the conductor 503b is formed inside. In addition, in the transistor 500, the conductor 503a and the conductor 503b are stacked, but the present invention is not limited to this. For example, the conductor 503 may have a single-layer structure or a stacked structure of three or more layers.

[0232] Here, as the conductor 503a, it is preferable to use a conductive material having a function of suppressing the diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, and copper atoms (not allowing the above impurities to pass through easily). In addition, it is preferable to use a conductive material having a function of suppressing the diffusion of oxygen (for example, at least one of oxygen atoms and oxygen molecules) (not allowing the above oxygen to pass through easily). In this specification, the function of suppressing the diffusion of impurities or oxygen refers to the function of suppressing the diffusion of any one or all of the above impurities and the above oxygen.

[0233] For example, by providing the conductor 503a with a function of suppressing the diffusion of oxygen, a decrease in conductivity due to oxidation of the conductor 503b can be suppressed.

[0234] In addition, when the conductor 503 also has a wiring function, it is preferable to use a highly conductive conductive material with tungsten, copper or aluminum as a main component as the conductor 503b. In this case, it is not necessary to provide the conductor 503a. In the drawings, the conductor 503b has a single-layer structure, but it can also have a laminated structure, for example, a laminated structure of titanium or titanium nitride and the above conductive materials can be used.

[0235] The insulator 520 , the insulator 522 , and the insulator 524 serve as a second gate insulating film.

[0236] Here, the insulator 524 in contact with the oxide 530 preferably contains oxygen exceeding the stoichiometric composition. In other words, it is preferable to form an excess oxygen region in the insulator 524. By providing the insulator containing excess oxygen in contact with the oxide 530, oxygen vacancies in the oxide 530 can be reduced, thereby improving the reliability of the transistor 500.

[0237] Specifically, as an insulator having an excess oxygen region, an oxide material from which a portion of oxygen is released by heating is preferably used. An oxide from which oxygen is released by heating means that the amount of oxygen released in terms of oxygen atoms in TDS (Thermal Desorption Spectroscopy) analysis is 1.0×10 18 atoms / cm 3 Above, preferably 1.0×10 19 atoms / cm 3 More preferably, 2.0×10 19 atoms / cm 3 Above, or 3.0×10 20 atoms / cm 3 In addition, the surface temperature of the film when performing the above-mentioned TDS analysis is preferably in the range of 100° C. to 700° C., or 100° C. to 400° C.

[0238] In addition, any one or more of heat treatment, microwave treatment, or RF treatment may be performed in such a manner that the insulator having the excess oxygen region and the oxide 530 are in contact with each other. By performing this treatment, water or hydrogen in the oxide 530 can be removed. For example, a reaction occurs in the oxide 530 in which VoH bonding is severed, in other words, a “V O H→V O +H" reaction can be dehydrogenated. A part of the hydrogen generated at this time is sometimes bonded with oxygen and removed from the oxide 530 or the insulator near the oxide 530 as H 2 O. In addition, a part of hydrogen may diffuse into the conductor 542 or be captured by the conductor 542 (also referred to as gettering).

[0239] In addition, as the above-mentioned microwave treatment, for example, it is preferred to use a device including a power supply for generating high-density plasma or a device including a power supply for applying RF to one side of the substrate. For example, by using a gas containing oxygen and a high-density plasma, a high-density oxygen radical can be generated, and by applying RF to one side of the substrate, the oxygen radical generated by the high-density plasma can be efficiently introduced into the oxide 530 or an insulator near the oxide 530. In addition, in the above-mentioned microwave treatment, the pressure is 133 Pa or more, preferably 200 Pa or more, and more preferably 400 Pa or more. In addition, as the gas introduced into the device for performing microwave treatment, for example, oxygen and argon are used, and the oxygen flow ratio (O / ) is 1:1. 2 / (O 2 +Ar)) is 50% or less, preferably 10% or more and 30% or less.

[0240] Furthermore, in the manufacturing process of transistor 500, it is preferred to perform heat treatment while the surface of oxide 530 is exposed. The heat treatment can be performed, for example, at a temperature of 100°C or higher and 450°C or lower, more preferably 350°C or higher and 400°C or lower. In addition, the heat treatment is performed in an atmosphere of nitrogen gas or an inert gas or an atmosphere containing an oxidizing gas of 10 ppm or higher, 1% or higher, or 10% or higher. For example, the heat treatment is preferably performed in an oxygen atmosphere. Thus, oxygen can be supplied to oxide 530 to reduce oxygen vacancies (V O ). In addition, the heat treatment may be performed under reduced pressure. Alternatively, the heat treatment may be performed in an atmosphere of nitrogen gas or an inert gas, and then the heat treatment may be performed in an atmosphere of an oxidizing gas containing 10 ppm or more, 1% or more, or 10% or more to fill the oxygen that has been separated. Alternatively, the heat treatment may be performed in an atmosphere of an oxidizing gas containing 10 ppm or more, 1% or more, or 10% or more, and then the heat treatment may be performed continuously in an atmosphere of nitrogen gas or an inert gas.

[0241] In addition, by performing an oxidation treatment on the oxide 530, oxygen vacancies in the oxide 530 can be filled with the supplied oxygen. In other words, the “V O +O→null”. Furthermore, by reacting the hydrogen remaining in the oxide 530 with the supplied oxygen, the hydrogen can be removed as H 2 O (dehydration). This can prevent the hydrogen remaining in the oxide 530 from bonding with oxygen vacancies to form V O H.

[0242] When the insulator 524 has an excess oxygen region, the insulator 524 preferably has a function of suppressing diffusion of oxygen (for example, oxygen atoms, oxygen molecules, etc.) (making it difficult for the oxygen to permeate).

[0243] When the insulator 522 has a function of suppressing diffusion of oxygen or impurities, it is preferable because oxygen included in the oxide 530 does not diffuse toward the insulator 520. In addition, reaction between the conductor 503 and oxygen included in the insulator 524 or the oxide 530 can be suppressed.

[0244] As the insulator 522, for example, aluminum oxide, hafnium oxide, an oxide containing aluminum and hafnium (hafnium silicate), tantalum oxide, zirconium oxide, lead zirconate titanate (PZT), strontium titanate (SrTiO 3 ) or (Ba, Sr)TiO 3 A single layer or stack of insulators made of so-called high-k materials such as (BST). When miniaturization and high integration of transistors are being promoted, problems such as leakage current may occur due to the thinning of the gate insulating film. By using a high-k material as an insulator used as a gate insulating film, the gate potential during transistor operation can be reduced while maintaining the physical thickness.

[0245] In particular, it is preferable to use an insulator containing an oxide of one or both of aluminum and hafnium as an insulating material having a function of suppressing the diffusion of impurities and oxygen (not allowing the above oxygen to pass easily). As an insulator containing an oxide of one or both of aluminum and hafnium, aluminum oxide, hafnium oxide, an oxide containing aluminum and hafnium (hafnium aluminate), etc. are preferably used. When the insulator 522 is formed using such a material, the insulator 522 is used as a layer that suppresses the release of oxygen from the oxide 530 or the entry of impurities such as hydrogen into the oxide 530 from the surrounding part of the transistor 500.

[0246] Alternatively, for example, aluminum oxide, bismuth oxide, germanium oxide, niobium oxide, silicon oxide, titanium oxide, tungsten oxide, yttrium oxide, or zirconium oxide may be added to the insulator. In addition, the insulator may be nitrided. In addition, silicon oxide, silicon oxynitride, or silicon nitride may be stacked on the insulator.

[0247] The insulator 520 preferably has thermal stability. For example, silicon oxide and silicon oxynitride are preferred because they have thermal stability. In addition, by combining an insulator of a high-k material with silicon oxide or silicon oxynitride, an insulator 520 or insulator 526 having a laminated structure with thermal stability and a high relative dielectric constant can be formed.

[0248] In addition, Fig.16A , Fig. 16B In the transistor 500, the insulator 520, the insulator 522, and the insulator 524 are shown as the second gate insulating film having a three-layer stacked structure, but the second gate insulating film may also have a single-layer structure, a two-layer structure, or a stacked structure of four or more layers. In this case, the stacked structure is not limited to being made of the same material, and a stacked structure made of different materials may be used.

[0249] In the transistor 500, a metal oxide used as an oxide semiconductor is preferably used for the oxide 530 including the channel formation region. For example, as the oxide 530, a metal oxide such as In-M-Zn oxide (the element M is one or more selected from aluminum, gallium, yttrium, copper, vanadium, beryllium, boron, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten and magnesium, etc.) is preferably used. As an In-M-Zn oxide that can be used as the oxide 530, a CAAC (c-axis-aligned crystalline)-OS (oxide semiconductor) or CAC (cloud-aligned composite)-OS having a distorted crystal structure and having c-axis orientation and multiple nanocrystals connected in the ab plane direction can be used. In addition, as the oxide 530, In-Ga oxide and In-Zn oxide can also be used.

[0250] In addition, for example, a metal oxide with a low carrier concentration is preferably used as the oxide 530. When reducing the carrier concentration of the metal oxide, it is sufficient to reduce the impurity concentration and defect state density in the metal oxide. In this specification, etc., the situation where the impurity concentration is low and the defect state density is low refers to high-purity intrinsic or substantially high-purity intrinsic. In addition, as impurities in the metal oxide, for example, there are hydrogen, nitrogen, alkali metals, alkaline earth metals, iron, nickel, silicon, etc.

[0251] In particular, since hydrogen contained in the metal oxide reacts with oxygen bonded to the metal atom to form water, oxygen vacancies (also called V vacancies) may be formed in the metal oxide. O:oxygen vacancy). When the channel formation region in the metal oxide contains oxygen vacancies, the transistor sometimes has a normally-on characteristic. In addition, when hydrogen enters the oxygen vacancy and is used as a donor, electrons as carriers are sometimes generated. In addition, sometimes part of the hydrogen is bonded to oxygen in the metal atom to generate electrons as carriers. Therefore, transistors using metal oxides containing a large amount of hydrogen tend to have a normally-on characteristic. In addition, when hydrogen enters the oxygen vacancy in the metal oxide, sometimes the oxygen vacancy is bonded to the hydrogen to form V O H.V O H is used as a donor, and sometimes generates electrons as carriers. In addition, sometimes part of the hydrogen generates electrons as carriers with oxygen bonded to metal atoms. Therefore, transistors using metal oxides containing a large amount of hydrogen tend to have normally-on characteristics. In addition, since hydrogen in metal oxides is easily moved due to heat, electric field, etc., when metal oxides contain a large amount of hydrogen, the reliability of the transistor may be reduced. In one embodiment of the present invention, it is preferred to minimize the V O H to achieve high purity intrinsic or substantially high purity intrinsic. Like this, in order to obtain V O It is important to remove impurities such as water and hydrogen from the metal oxide (sometimes described as dehydration or dehydrogenation treatment) and to supply oxygen to fill oxygen vacancies in the metal oxide (sometimes described as oxidation treatment). O A metal oxide in which impurities such as H are sufficiently reduced is used in a channel formation region of a transistor, and thus can provide stable electrical characteristics.

[0252] Defects in which hydrogen enters oxygen vacancies may be used as donors for metal oxides. However, it is difficult to quantitatively evaluate this defect. Therefore, in metal oxides, evaluation is sometimes performed not by donor concentration but by carrier concentration. Therefore, in this specification, etc., sometimes as a parameter of the metal oxide, instead of using donor concentration, carrier concentration assuming a state where no electric field is applied is used. That is, the "carrier concentration" recorded in this specification, etc. may sometimes be referred to as "donor concentration".

[0253] Therefore, it is preferable to reduce the amount of hydrogen in the oxide 530 as much as possible. Specifically, in the metal oxide, the hydrogen concentration obtained by secondary ion mass spectrometry (SIMS) is less than 1×10 20 atoms / cm 3 , preferably less than 1×10 19 atoms / cm 3 , more preferably less than 5×10 18 atoms / cm 3 , and more preferably less than 1×1018 atoms / cm 3 By using a metal oxide in which impurities such as hydrogen are sufficiently reduced in the channel formation region of a transistor, stable electrical characteristics can be imparted.

[0254] Furthermore, the carrier concentration of the metal oxide in the channel formation region is preferably 1×10 18 cm -3 Below, more preferably below 1×10 17 cm -3 , and more preferably less than 1×10 16 cm -3 , and more preferably less than 1×10 13 cm -3 , and more preferably less than 1×10 12 cm -3 Note that there is no particular restriction on the lower limit of the carrier concentration of the metal oxide in the channel formation region, and it may be, for example, 1×10 -9 cm -3 .

[0255] The metal oxide used as the channel formation region in the oxide 530 preferably has a band gap of 2 eV or more, preferably 2.5 eV or more. By using a metal oxide with a wide band gap, the off-state current of the transistor can be reduced.

[0256] In the oxide 530, when the oxide 530a is provided below the oxide 530b, diffusion of impurities from the structure formed below the oxide 530a to the oxide 530b can be suppressed. When the oxide 530c is provided above the oxide 530b, diffusion of impurities from the structure formed above the oxide 530c to the oxide 530b can be suppressed.

[0257] In addition, the oxide 530 preferably has a stacked structure of oxides having different atomic number ratios of each metal atom. Specifically, the atomic number ratio of the element M in the constituent elements of the metal oxide used for the oxide 530a is preferably greater than the atomic number ratio of the element M in the constituent elements of the metal oxide used for the oxide 530b. In addition, the atomic number ratio of the element M relative to In in the metal oxide used for the oxide 530a is preferably greater than the atomic number ratio of the element M relative to In in the metal oxide used for the oxide 530b. In addition, the atomic number ratio of In relative to the element M in the metal oxide used for the oxide 530b is preferably greater than the atomic number ratio of In relative to the element M in the metal oxide used for the oxide 530a. In addition, the metal oxide that can be used for the oxide 530a or the oxide 530b can be used for the oxide 530c.

[0258] It is preferable that the energy of the conduction band bottom of the oxide 530a and the oxide 530c is higher than the energy of the conduction band bottom of the oxide 530b. In other words, the electron affinity of the oxide 530a and the oxide 530c is preferably lower than the electron affinity of the oxide 530b.

[0259] Here, in the junction of oxide 530a, oxide 530b, and oxide 530c, the energy level of the conduction band bottom changes smoothly. In other words, the above situation can also be expressed as the energy level of the conduction band bottom of the junction of oxide 530a, oxide 530b, and oxide 530c continuously changes or continuously joins. For this reason, it is preferable to reduce the defect state density of the mixed layer formed at the interface between oxide 530a and oxide 530b and the interface between oxide 530b and oxide 530c.

[0260] Specifically, by making the oxide 530a and the oxide 530b, and the oxide 530b and the oxide 530c contain a common element (as a main component) in addition to oxygen, a mixed layer with a low defect state density can be formed. For example, when the oxide 530b is an In-Ga-Zn oxide, In-Ga-Zn oxide, Ga-Zn oxide, gallium oxide, etc. are preferably used as the oxide 530a and the oxide 530c.

[0261] At this time, the main path of the carrier is oxide 530b. By making oxide 530a and oxide 530c have the above structure, the defect state density at the interface between oxide 530a and oxide 530b and the interface between oxide 530b and oxide 530c can be reduced. Therefore, the influence of interface scattering on carrier conduction is reduced, and the on-state current of transistor 500 can be increased.

[0262] Conductors 542a and 542b used as source and drain electrodes are provided on the oxide 530b. As the conductors 542a and 542b, metal elements selected from aluminum, chromium, copper, silver, gold, platinum, tantalum, nickel, titanium, molybdenum, tungsten, hafnium, vanadium, niobium, manganese, magnesium, zirconium, beryllium, indium, ruthenium, iridium, strontium, and lanthanum, alloys containing the above metal elements as components, or alloys combining the above metal elements are preferably used. For example, tantalum nitride, titanium nitride, tungsten, nitrides containing titanium and aluminum, nitrides containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, oxides containing strontium and ruthenium, oxides containing lanthanum and nickel, etc. are preferably used. In addition, tantalum nitride, titanium nitride, nitride containing titanium and aluminum, nitride containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, oxide containing strontium and ruthenium, oxide containing lanthanum and nickel are conductive materials that are not easily oxidized or materials that maintain conductivity even when absorbing oxygen, so they are preferred. Metal nitride films such as tantalum nitride have barrier properties against hydrogen or oxygen, so they are more preferred.

[0263] In addition, although Fig.16A Although the single-layer structure of the conductor 542a and the conductor 542b is shown, a stacked structure of two or more layers may be adopted. For example, it is preferable to stack a tantalum nitride film and a tungsten film. Alternatively, a titanium film and an aluminum film may be stacked. Alternatively, a two-layer structure of stacking an aluminum film on a tungsten film, a two-layer structure of stacking a copper film on a copper-magnesium-aluminum alloy film, a two-layer structure of stacking a copper film on a titanium film, or a two-layer structure of stacking a copper film on a tungsten film may be adopted.

[0264] Alternatively, a three-layer structure may be used in which an aluminum film or a copper film is stacked on a titanium film or a titanium nitride film and a titanium film or a titanium nitride film is formed thereon, or an aluminum film or a copper film is stacked on a molybdenum film or a molybdenum nitride film and a molybdenum film or a molybdenum nitride film is formed thereon. Alternatively, a transparent conductive material containing indium oxide, tin oxide, or zinc oxide may be used.

[0265] In addition, if Fig.16A As shown, sometimes, a region 543a and a region 543b are formed as a low resistance region at the interface between the oxide 530 and the conductor 542a (conductor 542b) and in the vicinity thereof. In this case, the region 543a is used as one of the source region and the drain region, and the region 543b is used as the other of the source region and the drain region. In addition, a channel formation region is formed in a region sandwiched between the region 543a and the region 543b.

[0266] The oxygen concentration of the region 543a (region 543b) may be reduced by providing the above-mentioned conductor 542a (conductor 542b) in contact with the oxide 530. In addition, a metal compound layer including a metal contained in the conductor 542a (conductor 542b) and a component of the oxide 530 may be formed in the region 543a (region 543b). In this case, the carrier concentration of the region 543a (region 543b) increases, and the region 543a (region 543b) becomes a low resistance region.

[0267] In addition, the conductor 542a (conductor 542b) and the oxide 530 are in contact with each other, and oxygen in the oxide 530 diffuses into the electrode, so that the conductor may be oxidized. The possibility that the conductivity of the conductor decreases due to the oxidation of the conductor increases. Note that the diffusion of oxygen in the oxide 530 into the conductor can also be referred to as the conductor absorbing oxygen in the oxide 530.

[0268] In addition, when the oxygen in the oxide 530 diffuses into the conductor 542a (conductor 542b), another layer may be formed at the interface between the oxide 530 and the conductor. Because the other layer contains more oxygen than the above-mentioned conductor 542a (conductor 542b), it is speculated that the other layer has insulating properties. At this time, it can be considered that the three-layer structure of the above-mentioned conductor 542a (conductor 542b), the other layer and the oxide 530 is a three-layer structure composed of metal-insulator-semiconductor, which is sometimes also called MIS (Metal-Insulator-Semiconductor) structure or a diode connection structure based on the MIS structure.

[0269] The insulator 544 is provided so as to cover the conductors 542 a and 542 b and suppress oxidation of the conductors 542 a and 542 b. In this case, the insulator 544 may be provided so as to cover the side surface of the oxide 530 and to be in contact with the insulator 524.

[0270] The insulator 544 can be made of a metal oxide containing one or more metals selected from hafnium, aluminum, gallium, yttrium, zirconium, tungsten, titanium, tantalum, nickel, germanium, neodymium, lanthanum, or magnesium. Alternatively, the insulator 544 can be made of silicon nitride oxide or silicon nitride.

[0271] In particular, as the insulator 544, aluminum oxide, hafnium oxide, an oxide containing aluminum and hafnium (hafnium aluminate), etc., which are insulators containing oxides of one or both of aluminum and hafnium, are preferably used. In particular, hafnium aluminate has higher heat resistance than hafnium oxide film. Therefore, it is not easy to crystallize in the heat treatment of the subsequent process, so it is preferred. In addition, when the conductor 542a and the conductor 542b are materials with oxidation resistance or their conductivity does not significantly decrease even if oxygen is absorbed, it is not necessary to provide the insulator 544. It can be designed appropriately according to the required transistor characteristics.

[0272] By including the insulator 544, impurities such as water and hydrogen contained in the insulator 580 can be prevented from diffusing into the oxide 530b through the oxide 530c and the insulator 550. In addition, oxidation of the conductor 560 by excess oxygen contained in the insulator 580 can be prevented.

[0273] The insulator 550 is used as a first gate insulating film. The insulator 550 is preferably arranged in contact with the inner side (top surface and side surface) of the oxide 530c. The insulator 550 is preferably formed using an insulator that contains excess oxygen and releases oxygen by heating, similarly to the insulator 524 described above.

[0274] Specifically, silicon oxide containing excess oxygen, silicon oxynitride, silicon nitride oxide, silicon nitride, silicon oxide added with fluorine, silicon oxide added with carbon, silicon oxide added with carbon and nitrogen, and silicon oxide having pores can be used. In particular, silicon oxide and silicon oxynitride are preferred because they have thermal stability.

[0275] By providing an insulator that releases oxygen by heating so as to be in contact with the top surface of the oxide 530c as the insulator 550, oxygen can be efficiently supplied from the insulator 550 to the channel formation region of the oxide 530b through the oxide 530c. In addition, as with the insulator 524, it is preferable to reduce the concentration of impurities such as water or hydrogen in the insulator 550. The thickness of the insulator 550 is preferably not less than 1 nm and not more than 20 nm.

[0276] In order to efficiently supply the excess oxygen contained in the insulator 550 to the oxide 530, a metal oxide may be provided between the insulator 550 and the conductor 560. The metal oxide preferably suppresses the diffusion of oxygen from the insulator 550 to the conductor 560. By providing a metal oxide that suppresses the diffusion of oxygen, the diffusion of excess oxygen from the insulator 550 to the conductor 560 is suppressed. In other words, the amount of excess oxygen supplied to the oxide 530 can be suppressed from decreasing. In addition, the oxidation of the conductor 560 due to the excess oxygen can be suppressed. As the metal oxide, a material that can be used for the insulator 544 can be used.

[0277] In addition, similar to the second gate insulating film, the insulator 550 may also have a laminated structure. When miniaturization and high integration of transistors are performed, the thinning of the gate insulating film sometimes leads to problems such as leakage current. Therefore, by making the insulator used as the gate insulating film have a laminated structure of a high-k material and a thermally stable material, the gate potential during operation of the transistor can be reduced while maintaining the physical thickness. In addition, a laminated structure with thermal stability and a high relative dielectric constant can be realized.

[0278] exist Fig.16A and Fig. 16B In the embodiment, the conductor 560 used as the first gate electrode has a two-layer structure, but may have a single-layer structure or a stacked-layer structure of three or more layers.

[0279] As the conductor 560a, it is preferable to use a conductor having a property of suppressing hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, nitrogen oxide molecules (N 2 O, NO, NO 2, copper atoms, etc.) and other impurities. In addition, it is preferred to use a conductive material that has the function of inhibiting the diffusion of oxygen (for example, at least one of oxygen atoms, oxygen molecules, etc.). By making the conductor 560a have the function of inhibiting the diffusion of oxygen, it is possible to inhibit the oxidation of the conductor 560b due to the oxygen contained in the insulator 550 and the decrease in conductivity. As a conductive material having the function of inhibiting the diffusion of oxygen, for example, tantalum, tantalum nitride, ruthenium or ruthenium oxide is preferably used. In addition, as the conductor 560a, an oxide semiconductor that can be applied to the oxide 530 can be used. In this case, by forming the conductor 560b by a sputtering method, the resistance value of the conductor 560a can be reduced to make it a conductor. It can be called an OC (Oxide Conductor) electrode.

[0280] As the conductor 560b, a conductive material mainly composed of tungsten, copper or aluminum is preferably used. Since the conductor 560b is also used as wiring, it is preferable to use a conductor with high conductivity. The conductor 560b may also have a laminated structure, for example, a laminated structure of titanium or titanium nitride and the above conductive materials may be used.

[0281] The insulator 580 is preferably disposed on the conductor 542a and the conductor 542b via the insulator 544. The insulator 580 preferably has an excess oxygen region. For example, the insulator 580 preferably includes silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, silicon oxide added with fluorine, silicon oxide added with carbon, silicon oxide added with carbon and nitrogen, silicon oxide with pores, or resin. In particular, silicon oxide and silicon oxynitride are thermally stable and therefore are preferred. In particular, silicon oxide and silicon oxide with pores are preferred because they are easy to form an excess oxygen region in the subsequent process.

[0282] The insulator 580 preferably has an excess oxygen region. By providing the insulator 580 that releases oxygen by heating in contact with the oxide 530c, the oxygen in the insulator 580 can be efficiently supplied to the oxide 530 through the oxide 530c. In addition, the concentration of impurities such as water and hydrogen in the insulator 580 is preferably reduced.

[0283] The opening of the insulator 580 is formed so as to overlap with the region between the conductor 542a and the conductor 542b. Thus, the conductor 560 is provided so as to be embedded in the opening of the insulator 580 and in the region between the conductor 542a and the conductor 542b.

[0284] When miniaturizing semiconductor devices, it is necessary to shorten the gate length, but it is necessary to prevent the conductivity of the conductor 560 from decreasing. For this reason, when the thickness of the conductor 560 is increased, the conductor 560 may have a shape with a high aspect ratio. In this embodiment, since the conductor 560 is provided so as to fill the opening of the insulator 580, even if the conductor 560 has a shape with a high aspect ratio, the conductor 560 does not collapse during the process.

[0285] The insulator 574 is preferably provided so as to be aligned with the top surface of the insulator 580, the top surface of the conductor 560, and the top surface of the insulator 550. By forming the insulator 574 by sputtering, an excess oxygen region can be formed in the insulator 550 and the insulator 580. Thus, oxygen can be supplied to the oxide 530 from the excess oxygen region.

[0286] For example, as the insulator 574, a metal oxide containing one or two or more selected from hafnium, aluminum, gallium, yttrium, zirconium, tungsten, titanium, tantalum, nickel, germanium, magnesium, and the like can be used.

[0287] In particular, aluminum oxide has high barrier properties and can inhibit the diffusion of hydrogen and nitrogen even in a thin film of 0.5 nm to 3.0 nm. Therefore, aluminum oxide formed by sputtering can be used as an oxygen supply source while also functioning as a barrier film for impurities such as hydrogen.

[0288] In addition, after forming the transistor 500, an opening may be formed around the transistor 500, and an insulator having a high barrier property to hydrogen or water may be formed to cover the opening. By wrapping the transistor 500 with the above-mentioned high barrier insulator, it is possible to prevent moisture and hydrogen from entering from the outside. Alternatively, multiple transistors 500 may be wrapped with an insulator having a high barrier property to hydrogen or water. In addition, in the case of forming an opening around the transistor 500, for example, when an opening is formed to reach the insulator 514 or the insulator 522 and the above-mentioned high barrier insulator is formed in contact with the insulator 514 or the insulator 522, it can also serve as a part of the manufacturing process of the transistor 500, so it is preferred. In addition, as an insulator having a high barrier property to hydrogen or water, for example, the same material as the insulator 522 can be used.

[0289] In addition, an insulator 581 used as an interlayer film is preferably provided over the insulator 574. As with the insulator 524 and the like, the concentration of impurities such as water and hydrogen in the insulator 581 is preferably reduced.

[0290] In addition, conductors 540a and 540b are arranged in openings formed in insulators 581, 574, 580, and 544. Conductors 540a and 540b are arranged to face each other via conductor 560. Conductors 540a and 540b have the same structure as conductors 546 and 548 described later.

[0291] An insulator 582 is provided on the insulator 581. A substance having a barrier property against oxygen or hydrogen is preferably used for the insulator 582. Therefore, the insulator 582 can be made of the same material as the insulator 514. For example, the insulator 582 is preferably made of a metal oxide such as aluminum oxide, hafnium oxide, or tantalum oxide.

[0292] In particular, aluminum oxide has a high barrier effect of preventing oxygen and impurities such as hydrogen and moisture that cause changes in the electrical characteristics of the transistor from penetrating. Therefore, during and after the manufacturing process of the transistor, aluminum oxide can prevent impurities such as hydrogen and moisture from entering the transistor 500. In addition, aluminum oxide can suppress the release of oxygen from the oxide constituting the transistor 500. Therefore, aluminum oxide is suitable for use as a protective film for the transistor 500.

[0293] In addition, an insulator 586 is provided on the insulator 582. As the insulator 586, the same material as the insulator 320 can be used. In addition, by using a material with a low dielectric constant as these insulators, the parasitic capacitance generated between the wirings can be reduced. For example, as the insulator 586, a silicon oxide film or a silicon oxynitride film can be used.

[0294] In addition, the conductor 546 and the conductor 548 are buried in the insulator 520 , the insulator 522 , the insulator 524 , the insulator 544 , the insulator 580 , the insulator 574 , the insulator 581 , the insulator 582 , and the insulator 586 .

[0295] The conductor 546 and the conductor 548 are used as plugs or wirings connected to the capacitor 600, the transistor 500, or the transistor 300. The conductor 546 and the conductor 548 can be provided using the same material as the conductor 328 and the conductor 330.

[0296] Next, a capacitor 600 is provided above the transistor 500 . The capacitor 600 includes a conductor 610 , a conductor 620 , and an insulator 630 .

[0297] In addition, a conductor 612 may be provided over the conductor 546 and the conductor 548. The conductor 612 is used as a plug or wiring connected to the transistor 500. The conductor 610 is used as an electrode of the capacitor 600. In addition, the conductor 612 and the conductor 610 may be formed at the same time.

[0298] As the conductor 612 and the conductor 610, a metal film containing an element selected from molybdenum, titanium, tantalum, tungsten, aluminum, copper, chromium, neodymium, and scandium, or a metal nitride film containing the above elements as a component (tantalum nitride film, titanium nitride film, molybdenum nitride film, tungsten nitride film), etc. can be used. Alternatively, a conductive material such as indium tin oxide, indium oxide containing tungsten oxide, indium zinc oxide containing tungsten oxide, indium oxide containing titanium oxide, indium tin oxide containing titanium oxide, indium zinc oxide, indium tin oxide added with silicon oxide, etc. can also be used.

[0299] exist Fig.14 In the embodiment, the conductor 612 and the conductor 610 have a single-layer structure, but the present invention is not limited thereto and they may have a stacked structure of two or more layers. For example, a conductor having high compactness with the conductor having barrier properties and the conductor having high conductivity may be formed between the conductor having barrier properties and the conductor having high conductivity.

[0300] The conductor 620 is provided so as to overlap the conductor 610 via the insulator 630. Conductive materials such as metal materials, alloy materials, and metal oxide materials can be used as the conductor 620. It is preferable to use a high melting point material such as tungsten or molybdenum that has both heat resistance and conductivity, and tungsten is particularly preferable. When the conductor 620 is formed simultaneously with other components such as a conductor, a low-resistance metal material such as Cu (copper) or Al (aluminum) can be used.

[0301] An insulator 640 is provided on the conductor 620 and the insulator 630. The insulator 640 can be provided using the same material as the insulator 320. In addition, the insulator 640 can be used as a planarization film that covers the concavo-convex shape thereunder.

[0302] By adopting this structure, the reliability of a semiconductor device using a transistor including an oxide semiconductor can be improved while suppressing the variation of the electrical characteristics. In addition, miniaturization or high integration can be achieved in a battery control circuit using a transistor including an oxide semiconductor.

[0303] A memory using an OS transistor according to one embodiment of the present invention will be described below.

[0304] The power storage device included in one embodiment of the present invention preferably has a memory. As the memory, a memory device using an OS transistor can be applied. For example, NOSRAM (registered trademark) or DOSRAM (registered trademark) described below can be used.

[0305] NOSRAM refers to a gain cell type DRAM in which the write transistor of the memory cell is formed by an OS transistor. NOSRAM is an abbreviation of Nonvolatile Oxide Semiconductor RAM. The following is a structural example of NOSRAM.

[0306] <nosram>

[0307] Fig.17A 2 is a block diagram showing a structural example of a NOSRAM. Power domains 242 and 243 and power switches 245 to 247 are provided in the NOSRAM 240. A memory cell array 250 is provided in the power domain 242, and a peripheral circuit of the NOSRAM 240 is provided in the power domain 243. The peripheral circuit includes a control circuit 251, a row circuit 252, and a column circuit 253.

[0308] Voltages VDDD, VSSS, VDHW, VDHR, VBG2, clock signal GCLK2, address signal, CE, WE, PSE5 are input from the outside to NOSRAM 240. Signals CE and WE are chip enable signals and write enable signals. Signal PSE5 controls the opening and closing of power switches 245 to 247. Power switches 245 to 247 control the input of voltages VDDD, VDHW, and VDHR to power domain 243, respectively.

[0309] In addition, the voltage and signal input to the NOSRAM 240 are appropriately selected according to the circuit structure and operation method of the NOSRAM 240. For example, the NOSRAM 240 may also be provided with a power domain that is not subject to power gating and a power gating control circuit that generates the signal PSE5.

[0310] The memory cell array 250 includes memory cells 10 , write word lines WWL, read word lines RWL, write bit lines WBL, read bit lines RBL, and source lines SL.

[0311] like Fig. 17B As shown, the memory cell 10 is a 2T1C (2 transistors 1 capacitor) type gain cell, including a node SN1, transistors M1, M2, and a capacitor C1. The transistor M1 is a write transistor and is an OS transistor including a back gate. The back gate of the transistor M1 is electrically connected to the wiring BGL2 for supplying the voltage VBG2. The transistor M2 is a read transistor and is a p-channel Si transistor. The capacitor C1 is a storage capacitor for holding the voltage of the node SN1.

[0312] The voltages VDDD and VSSS are voltages representing data "1" and "0", respectively. Note that the high-level voltages of the write word lines WWL and RWL are VDHW and VHDR.

[0313] Fig.18A FIG. 2 shows an example of the structure of the memory cell array 250. Fig.18A In the memory cell array 250 shown, one source line is provided for two adjacent rows.

[0314] In the memory cell 10, in principle, there is no limit to the number of writes, and data can be rewritten with low energy, so data retention does not consume power. Since the transistor M1 is an OS transistor with an extremely small off-state current, the memory cell 10 can retain data for a long time. Therefore, by forming the cache memory devices 202, 203 with NOSRAM240, the cache memory devices 202, 203 can be made into non-volatile low-power memory devices.

[0315] The circuit structure of the memory cell 10 is not limited to Fig. 17B For example, the read transistor M2 may be an OS transistor or an n-channel Si transistor including a back gate. Alternatively, the memory cell 10 may also be a 3T-type gain cell. For example, Fig.18B and Fig. 18C An example of a 3T-type gain cell is shown. Fig.18B The memory cell 15 shown includes transistors M3 to M5, a capacitor C3, and a node SN3. The transistors M3 to M5 are respectively a write transistor, a read transistor, and a select transistor. The transistor M3 is an OS transistor including a back gate, and the transistors M4 and M5 are p-channel Si transistors. The transistors M4 and M5 can be composed of n-channel Si transistors or OS transistors including a back gate. Fig. 18C In the illustrated memory cell 16, three transistors are formed by OS transistors including back gates.

[0316] Node SN3 is a holding node. Capacitor C3 is a storage capacitor for holding the voltage of node SN3. Capacitor C3 may be intentionally not provided, and the storage capacitor may be formed by the gate capacitance of transistor M4 or the like. Wiring PDL is supplied with a fixed voltage (e.g., VDDD). Wiring PDL is a wiring that replaces source line SL, and is supplied with voltage VDDD, for example.

[0317] The control circuit 251 has a function of controlling the overall operation of the NOSRAM 240. For example, the control circuit 251 performs a logic operation on the signals CE and WE to determine whether an access from the outside is a write access or a read access.

[0318] The row circuit 252 has the function of selecting the write word line WWL and the read word line of the row specified by the address signal. The column circuit 253 has the function of writing data to the write bit line of the column specified by the address signal and reading data from the read bit line WBL of the column.

[0319] <dosram>

[0320] DOSRAM is a RAM that includes 1T1C type storage cells and is the abbreviation of Dynamic Oxide SemiconductorRAM. Fig.19A and Fig.19B Description of DOSRAM.

[0321] like Fig.19A As shown, the memory cell 16 of the DOSRAM 351 is electrically connected to the bit line BL (or BLB), the word line WL, the wiring BGL6 and the PL. The bit line BLB is an inversion bit line. For example, the wiring BGL6 and the PL are supplied with voltages VBG6 and VSSS. The memory cell 16 includes a transistor M6 and a capacitor C6. The transistor M6 is an OS transistor including a back gate.

[0322] Since the data is rewritten by charging and discharging the capacitor C6, there is no limit to the number of rewrites of the DOSRAM 351 in principle, and data can be written and read with low power consumption. In addition, the circuit structure of the storage unit 16 is simple, and it is easy to achieve large capacity. The write transistor of the storage unit 16 is an OS transistor, so the retention time of the DOSRAM 351 is very long compared with DRAM. Therefore, the refresh frequency can be reduced, or the refresh operation is not required, and the power consumption required for the refresh operation can be reduced.

[0323] like Fig.19B As shown, in the DOSRAM 351, the memory cell array 361 can be stacked on the peripheral circuit 365. This is because the transistor M6 of the memory cell 16 is an OS transistor.

[0324] In the memory cell array 361, a plurality of memory cells 16 are arranged in rows and columns, and bit lines BL, BLB, word lines WL, wirings BGL6 and PL are provided according to the arrangement of the memory cells 16. A control circuit, a row circuit, and a column circuit are provided in the peripheral circuit 365. The row circuit selects the word line WL to be accessed, etc. The column circuit writes and reads data to the bit line pair composed of BL and BLB, etc.

[0325] In order to perform power gating of the peripheral circuit 365, power switches 371 and 373 are provided. The power switches 371 and 373 respectively control the input of the voltages VDDD and VDHW6 supplied to the peripheral circuit 365. Note that the voltage VDHW6 is a high level voltage of the word line WL. The turning on and off of the power switches 371 and 373 is controlled by the signal PSE6. For example, the signal PSE6 is generated in the PMU 113.

[0326] This embodiment mode can be combined with the description of other embodiment modes as appropriate.

[0327] (Implementation 3)

[0328] In this embodiment, refer to Fig. 20A and Fig. 20B An example in which the battery control circuit described in the above embodiment is used as an electronic component will be described.

[0329] exist Fig. 20A In the embodiment, an example of using the battery control circuit described in the above embodiment as an electronic component is described. Note that the electronic component is also called a semiconductor package or an IC package. The electronic component has different specifications and names depending on the terminal extraction direction or the shape of the terminal. In this embodiment, an example thereof is described.

[0330] By combining a plurality of members that can be attached to and detached from the printed circuit board in an assembly process (post-process), a circuit portion composed of OS transistors or Si transistors is completed.

[0331] The post-process can be carried out Fig. 20A The process shown is completed. Specifically, after the element substrate obtained by the previous process is completed (step S1), the back side of the substrate is ground (step S2). By thinning the substrate at this stage, the warping of the substrate generated in the previous process can be reduced, thereby achieving miniaturization of the component.

[0332] The back side of the substrate is ground and a dicing process is performed to divide the substrate into a plurality of chips. In addition, a die bonding process is performed to mount the cut chips on a lead frame and achieve bonding (step S3). The bonding of the chip and the lead frame in the die bonding process can be appropriately selected according to the product, such as bonding using a resin or bonding using an adhesive tape. In addition, in the die bonding process, each chip can also be mounted on an interposer to achieve bonding.

[0333] Next, wire bonding is performed to electrically connect the leads of the lead frame to the electrodes on the chip through metal wires (step S4). Silver wires or gold wires can be used as the metal wires. In addition, ball bonding or wedge bonding can be used for wire bonding.

[0334] The chip after wire bonding is subjected to a molding process in which the chip is sealed with epoxy resin or the like (step S5). By performing the molding process, the interior of the electronic component is filled with resin, which can reduce damage to the circuit part and metal wires installed inside the electronic component due to mechanical external forces, and can also reduce the degradation of characteristics caused by moisture or dust.

[0335] Next, the lead of the lead frame is plated, and the lead is cut and formed (step S6). The plating process can prevent the lead from rusting, and when the lead is subsequently mounted on a printed circuit board, soldering can be performed more reliably.

[0336] Next, the package surface is subjected to printing (marking) (step S7), and after a final inspection process (step S8), the electronic component including the circuit section including the PLD is completed (step S9).

[0337] Fig. 20B A perspective schematic diagram showing the completed electronic component. Fig. 20B , a perspective schematic diagram of a QFP (Quad Flat Package) is shown as an example of an electronic component. Fig. 20B The electronic component 700 shown includes leads 701 and a circuit portion 703 . Fig. 20B The electronic component 700 shown is mounted on, for example, a printed circuit board 702. By combining a plurality of such electronic components 700 and electrically connecting them to each other on the printed circuit board 702, they can be mounted inside an electronic device. The completed circuit board 704 is provided inside an electronic device or the like.

[0338] (Implementation 4)

[0339] In this embodiment, the configuration of a power storage device and a power storage system that can use electronic components including the battery control circuit described in the above embodiment will be described.

[0340] [Cylindrical secondary battery]

[0341] Reference Fig.21A An example of a cylindrical secondary battery is described below. Fig.21A As shown, the top surface of the cylindrical secondary battery 400 includes a positive electrode cover (battery cover) 401, and the side and bottom surfaces thereof include a battery can (outer can) 402. The positive electrode cover 401 and the battery can (outer can) 402 are insulated by a gasket (insulating gasket) 410.

[0342] Fig. 21B It is a diagram schematically showing a cross section of a cylindrical secondary battery. Fig. 21B The cylindrical secondary battery shown has a positive electrode cover (battery cover) 601 on the top surface and a battery can (outer can) 602 on the side and bottom surfaces. The positive electrode cover and the battery can (outer can) 602 are insulated by a gasket (insulating gasket) 610.

[0343] A battery element in which a strip positive electrode 604 and a strip negative electrode 606 are wound with a separator 605 is arranged on the inner side of a hollow cylindrical battery can 602. Although not shown in the figure, the battery element is wound around a center pin. One end of the battery can 602 is closed and the other end is open. As the battery can 602, metals such as nickel, aluminum, titanium, etc., which are resistant to corrosion by the electrolyte, their alloys, or alloys of them and other metals (such as stainless steel, etc.) can be used. In addition, in order to prevent corrosion caused by the electrolyte, the battery can 602 is preferably covered with nickel or aluminum. On the inner side of the battery can 602, the battery element in which the positive electrode, the negative electrode and the separator are wound is sandwiched by a pair of opposing insulating plates 608 and insulating plates 609. In addition, a non-aqueous electrolyte (not shown) is injected into the interior of the battery can 602 in which the battery element is arranged. As a non-aqueous electrolyte, the same electrolyte as that of a coin-type secondary battery can be used.

[0344] Because the positive and negative electrodes used for cylindrical storage batteries are wound, the active material is preferably formed on both surfaces of the current collector. The positive electrode 604 is connected to the positive terminal (positive electrode current collector lead) 603, and the negative electrode 606 is connected to the negative terminal (negative electrode current collector lead) 607. Both the positive terminal 603 and the negative terminal 607 can be made of metal materials such as aluminum. The positive terminal 603 is resistance welded to the safety valve mechanism 613, and the negative terminal 607 is resistance welded to the bottom of the battery can 602. The safety valve mechanism 613 is electrically connected to the positive electrode cover 601 through a PTC (Positive Temperature Coefficient) element 611. When the internal pressure of the battery rises to exceed a specified threshold, the safety valve mechanism 613 cuts off the electrical connection between the positive electrode cover 601 and the positive electrode 604. In addition, the PTC element 611 is a thermistor whose resistance increases when the temperature rises, and limits the current by increasing the resistance to prevent abnormal heating. The PTC element can use barium titanate (BaTiO 3 ) types of semiconductor ceramics, etc.

[0345] Fig. 21C An example of a power storage system 415 is shown. The power storage system 415 includes a plurality of secondary batteries 400. The positive electrode of each secondary battery contacts a conductor 424 separated by an insulator 425, and the positive electrodes are electrically connected to each other. The conductor 424 is electrically connected to a control circuit 420 via a wiring 423. In addition, the negative electrode of each secondary battery is electrically connected to the control circuit 420 via a wiring 426. As the control circuit 420, the battery control circuit described in the above embodiment can be used.

[0346] Fig.21D An example of a power storage system 415 is shown. The power storage system 415 includes a plurality of secondary batteries 400, and the plurality of secondary batteries 400 are sandwiched between a conductive plate 413 and a conductive plate 414. The plurality of secondary batteries 400 are electrically connected to the conductive plate 413 and the conductive plate 414 through wiring 416. The plurality of secondary batteries 400 can be connected in parallel, in series, or in parallel and then in series. By configuring the power storage system 415 including the plurality of secondary batteries 400, a large amount of electric power can be obtained.

[0347] In addition, a temperature control device may be included between the plurality of secondary batteries 400. When the secondary battery 400 is overheated, it can be cooled by the temperature control device, and when the secondary battery 400 is overcooled, it can be heated by the temperature control device. Therefore, the performance of the power storage system 415 is not easily affected by the external temperature.

[0348] In addition, Fig.21D In the embodiment, the power storage system 415 is electrically connected to the control circuit 420 via the wiring 421 and the wiring 422. The battery control circuit described in the above embodiment can be used as the control circuit 420. The wiring 421 is electrically connected to the positive electrodes of the plurality of secondary batteries 400 via the conductive plate 413, and the wiring 422 is electrically connected to the negative electrodes of the plurality of secondary batteries 400 via the conductive plate 414.

[0349] [Secondary battery pack]

[0350] Next, refer to Fig.22A , Fig. 22B and Fig. 22C An example of a power storage system according to one embodiment of the present invention will be described.

[0351] Fig.22A 1 is a diagram showing the appearance of the secondary battery pack 531 . Fig. 22B 5 is a diagram for explaining the structure of a secondary battery pack 531. The secondary battery pack 531 includes a circuit board 501 and a secondary battery 513. A label 509 is attached to the secondary battery 513. The circuit board 501 is fixed by a sealing tape 515. In addition, the secondary battery pack 531 includes an antenna 517.

[0352] The circuit board 501 includes a control circuit 590. As the control circuit 590, the battery control circuit shown in the above embodiment can be used. Fig. 22B As shown, the circuit board 501 includes a control circuit 590. The circuit board 501 is electrically connected to the terminal 511. The circuit board 501 is electrically connected to the antenna 517, one 551 of the positive lead and the negative lead of the secondary battery 513, and the other 552 of the positive lead and the negative lead.

[0353] In addition, if Fig. 22C As shown, the secondary battery pack system may also include a circuit system 590a disposed on the circuit board 501 and a circuit system 590b electrically connected to the circuit board 501 via the terminal 511. For example, a part of the control circuit of one embodiment of the present invention is disposed in the circuit system 590a, and another part is disposed in the circuit system 590b.

[0354] In addition, the shape of antenna 517 is not limited to a coil shape, for example, it can be a linear or plate shape. In addition, antennas such as a planar antenna, an aperture antenna, a traveling wave antenna, an EH antenna, a magnetic field antenna, or a dielectric antenna can also be used. Alternatively, antenna 517 can also be a flat conductor. The flat conductor can also be used as one of the conductors for electric field coupling. In other words, antenna 517 can also be used as one of the two conductors possessed by a capacitor. Thus, not only electromagnetic and magnetic fields are utilized, but also electric fields can be utilized to exchange electric power.

[0355] The secondary battery pack 531 includes a layer 519 between the antenna 517 and the secondary battery 513. The layer 519 has a function of shielding the electromagnetic field from the secondary battery 513, for example. As the layer 519, a magnetic body can be used, for example.

[0356] The secondary battery 513 may also include a wound battery element. The battery element includes a negative electrode, a positive electrode, and a separator. The battery element is, for example, a film in which a negative electrode and a positive electrode are stacked with a separator interposed therebetween and the stacked layers are wound.

[0357] This embodiment mode can be combined with the description of other embodiment modes as appropriate.

[0358] (Implementation method 5)

[0359] In this embodiment, an example in which the power storage system according to one embodiment of the present invention is mounted on a vehicle is shown. Examples of the vehicle include automobiles, motorcycles, and bicycles.

[0360] When the power storage system is installed in a vehicle, a new generation of clean energy vehicles such as a hybrid electric vehicle (HEV), an electric vehicle (EV), or a plug-in hybrid electric vehicle (PHEV) can be realized.

[0361] exist Fig.23A , Fig. 23B and Fig.23C In the figure, a vehicle using the power storage system according to one embodiment of the present invention is exemplified. Fig.23A The automobile 8400 shown is an electric car that uses an electric motor as a power source for traveling. Alternatively, the automobile 8400 is a hybrid car that can appropriately use an electric motor or an engine as a power source for traveling. By using one embodiment of the present invention, a vehicle with a long driving distance can be realized. In addition, the automobile 8400 is equipped with a power storage system. The power storage system not only drives the electric motor 8406, but also can supply power to light-emitting devices such as headlights 8401 or interior lights (not shown).

[0362] The power storage system can also supply electric power to a display device such as a speedometer and a tachometer included in the automobile 8400. The power storage system can also supply electric power to a navigation system included in the automobile 8400.

[0363] exist Fig. 23B In the illustrated automobile 8500 , a power storage system 8024 included in the automobile 8500 can be charged by receiving electric power from an external charging device using a plug-in method or a contactless power supply method. Fig. 23B The case where a power storage system 8024 installed in a car 8500 is charged from a ground-mounted charging device 8021 via a cable 8022 is shown. When charging, as the charging method or the specifications of the connector, the prescribed methods such as CHAdeMO (registered trademark) or the combined charging system "Combined Charging System" can be appropriately used. As the charging device 8021, a charging station installed in a commercial facility or a home power supply can also be used. For example, the power storage system 8024 installed in the car 8500 can be charged by supplying power from the outside using plug-in technology. Charging can be performed by converting AC power into DC power using a conversion device such as an ACDC converter.

[0364] In addition, although not shown, it is also possible to install a power receiving device in the vehicle and supply power contactlessly from a power transmission device on the ground for charging. When a contactless power supply method is used, by assembling a power transmission device in a road or an outer wall, charging can be performed not only when the vehicle is parked but also when it is driving. In addition, the contactless power supply method can also be used to send and receive power between vehicles. Furthermore, a solar cell can be installed on the outside of the vehicle to charge the power storage system when the vehicle is parked or driving. Such contactless power supply can be achieved using an electromagnetic induction method or a magnetic field resonance method.

[0365] Fig.23C This is an example of a two-wheeled vehicle using the power storage system according to one embodiment of the present invention. Fig.23C The small motorcycle 8600 shown includes a power storage system 8602, a rearview mirror 8601, and a turn signal light 8603. The power storage system 8602 can supply power to the turn signal light 8603.

[0366] In addition, Fig.23C In the illustrated scooter 8600, the power storage system 8602 can be stored in the storage section 8604 under the seat. Even if the storage section 8604 under the seat is small, the power storage system 8602 can be stored in the storage section 8604 under the seat.

[0367] in addition, Fig.24A An example of an electric bicycle using the power storage system according to one embodiment of the present invention is described. Fig.24A The electric bicycle 8700 shown can use the power storage system of one embodiment of the present invention. The power storage system of one embodiment of the present invention includes, for example, a plurality of storage batteries, a protection circuit, and a neural network.

[0368] The electric bicycle 8700 includes a power storage system 8702. The power storage system 8702 supplies power to the motor that assists the rider. In addition, the power storage system 8702 is portable. Fig. 24B The power storage system 8702 taken out of the bicycle is shown. The power storage system 8702 has a plurality of storage batteries 8701 included in the power storage system of one embodiment of the present invention built in, and the remaining power and the like can be displayed on the display unit 8703. In addition, the power storage system 8702 includes a control circuit 8704 of one embodiment of the present invention. The control circuit 8704 is electrically connected to the positive electrode and the negative electrode of the storage battery 8701. As the control circuit 8704, the battery control circuit shown in the above embodiment can be used.

[0369] This embodiment mode can be combined with other embodiment modes as appropriate.

[0370] (Implementation method 6)

[0371] In this embodiment, an example in which the power storage system described in the above embodiment is incorporated into an electronic device will be described.

[0372] then, Fig.25A and Fig.25B An example of a tablet terminal (including a clamshell-type terminal) that can be folded in half is shown. Fig.25A and Fig.25B The tablet terminal 9600 shown includes a housing 9630a, a housing 9630b, a movable portion 9640 connecting the housing 9630a and the housing 9630b, a display portion 9631, a display mode switching switch 9626, a power switch 9627, a power saving mode switching switch 9625, a fastener 9629, and an operation switch 9628. By using a flexible panel for the display portion 9631, a tablet terminal having a larger display portion can be realized. Fig.25A The tablet terminal 9600 is shown in an open state. Fig.25B The tablet terminal 9600 is shown in a closed state.

[0373] The tablet terminal 9600 includes a power storage body 9635 inside a housing 9630a and a housing 9630b. The power storage body 9635 is provided in the housing 9630a and the housing 9630b through a movable portion 9640 .

[0374] The display portion 9631 can be partially used as a touch screen area, and data can be input by touching the displayed operation keys. In addition, keyboard buttons can be displayed on the display portion 9631 by touching the position of a keyboard display switch button on the touch screen with a finger, a stylus pen, or the like.

[0375] In addition, the display mode switching switch 9626 can switch the display direction such as vertical screen display and horizontal screen display, and switch between black and white display and color display. The power saving mode switching switch 9625 can set the display brightness to the most suitable brightness according to the amount of external light detected by the built-in optical sensor of the tablet terminal 9600 during use. In addition to the optical sensor, the tablet terminal can also have other detection devices such as sensors for detecting tilt such as gyroscopes and acceleration sensors built in.

[0376] Fig.25B The tablet terminal 9600 is folded in half and includes a housing 9630, a solar cell 9633, and a power storage system of one embodiment of the present invention. The power storage system includes a control circuit 9634 and a power storage body 9635. As the control circuit 9634, the battery control circuit described in the above embodiment mode can be used.

[0377] Furthermore, the tablet terminal 9600 can be folded in half, and thus the housing 9630a and the housing 9630b can be folded so as to overlap each other when not in use. By folding the housing 9630a and the housing 9630b, the display portion 9631 can be protected, and the durability of the tablet terminal 9600 can be improved.

[0378] also, Fig.25A and Fig.25B The tablet terminal shown can also have the following functions: displaying various information (static images, dynamic images, text images, etc.); displaying the calendar, date or time, etc. on the display unit; performing touch input operations or touch inputs for editing the information displayed on the display unit; controlling processing through various software (programs), etc.

[0379] The solar cell 9633 mounted on the surface of the tablet terminal can supply power to the touch screen, display portion, image signal processing portion, etc. Note that the solar cell 9633 can be provided on one surface or both surfaces of the housing 9630 so that the power storage body 9635 can be charged efficiently.

[0380] In addition, Fig.25A and Fig.25B The structure in which the control circuit using the battery control circuit shown in the above embodiment is used in a tablet terminal that can be folded in half is described, but other structures can also be used. Fig.25C As shown, it can be used in a notebook personal computer as a clamshell type terminal. Fig.25C The notebook personal computer 9601 includes a display portion 9631 in a housing 9630a and a keyboard portion 9636 in a housing 9630b. Fig.25A and Fig.25B The control circuit 9634 and the power storage body 9635 described above. As the control circuit 9634, the battery control circuit described in the above embodiment mode can be used.

[0381] Fig.26 Examples of other electronic devices are shown. Fig.26 In the embodiment of the present invention, the display device 8000 is an example of an electronic device equipped with a power storage system according to one embodiment of the present invention. Specifically, the display device 8000 is equivalent to a display device for receiving television broadcasts, and includes a frame 8001, a display unit 8002, a speaker unit 8003, and a secondary battery 8004. The detection system according to one embodiment of the present invention is provided inside the frame 8001. The display device 8000 can receive power supply from a commercial power supply and can use power stored in the secondary battery 8004.

[0382] As the display unit 8002, a semiconductor display device such as a liquid crystal display device, a light-emitting device having a light-emitting element such as an organic EL element in each pixel, an electrophoretic display device, a DMD (digital micromirror device), a PDP (plasma display panel), and an FED (field emission display) can be used.

[0383] In addition, the sound input device 8005 also uses a secondary battery. The sound input device 8005 includes the power storage system shown in the above embodiment. In addition to the wireless communication element, the sound input device 8005 also includes a plurality of sensors (optical sensor, temperature sensor, humidity sensor, air pressure sensor, illumination sensor, motion sensor, etc.) including a microphone, and can operate other devices according to user commands, for example, the power supply of the display device 8000 can be operated and the light amount of the lighting device 8100 can be adjusted. The sound input device 8005 can operate peripheral devices through sound, and can replace the manual remote control operation machine.

[0384] In addition, the voice input device 8005 includes wheels or a mechanical moving unit, moves in the direction in which the user's voice is heard and correctly understands the command with the built-in microphone, and displays its content on the display unit 8008 or enables touch input operations on the display unit 8008.

[0385] In addition, the sound input device 8005 can be used as a charging base for a portable information terminal 8009 such as a smartphone. The portable information terminal 8009 and the sound input device 8005 can receive power by wire or wirelessly. Since the portable information terminal 8009 does not need to be carried indoors, and it is necessary to avoid applying a load to the secondary battery and causing degradation while ensuring the necessary capacity, it is preferred that the secondary battery can be managed and repaired through the sound input device 8005. In addition, the sound input device 8005 includes a speaker 8007 and a microphone, so that hands-free calls can be made even when the portable information terminal 8009 is charged. In addition, when the capacity of the secondary battery of the sound input device 8005 is reduced, it can be charged wirelessly by moving in the direction of the arrow and connecting to the charging module 8010 connected to the external power source.

[0386] In addition, the sound input device 8005 can be placed on a table. In addition, the sound input device 8005 can be provided with wheels or a mechanical moving unit to move to a desired position, or the sound input device 8005 can be fixed to a desired position, such as on the floor, without a table or wheels.

[0387] In addition, the display device includes all display devices for displaying information, such as a display device for a personal computer or a display device for displaying advertisements, in addition to a display device for receiving television broadcasts.

[0388] exist Fig.26 In the embodiment of the present invention, the mounted lighting device 8100 is an example of an electronic device using a secondary battery 8103 controlled by a microprocessor (including an APS) for controlling charging. Specifically, the lighting device 8100 includes a housing 8101, a light source 8102, and a secondary battery 8103. Fig.26 8 shows an example in which the secondary battery 8103 is provided inside the ceiling 8104 in which the housing 8101 and the light source 8102 are installed, but the secondary battery 8103 may be provided inside the housing 8101. The lighting device 8100 can receive power from a commercial power source and use power stored in the secondary battery 8103.

[0389] In addition, although Fig.26 Although the example of the mounted lighting device 8100 installed on the ceiling 8104 is shown, the secondary battery 8103 can be used in a mounted lighting device installed other than the ceiling 8104, such as a side wall 8105, a floor 8106, or a window 8107, or can also be used in a desktop lighting device.

[0390] An artificial light source that artificially obtains light using electric power may be used as the light source 8102. Specifically, an example of the artificial light source includes an incandescent bulb, a discharge lamp such as a fluorescent lamp, and a light-emitting element such as an LED or an organic EL element.

[0391] exist Fig.26 In the embodiment, an air conditioner having an indoor unit 8200 and an outdoor unit 8204 is an example of an electronic device using a secondary battery 8203. Specifically, the indoor unit 8200 includes a housing 8201, an air outlet 8202, and a secondary battery 8203. Fig.26 , the secondary battery 8203 is provided in the indoor unit 8200, but the secondary battery 8203 may be provided in the outdoor unit 8204. Alternatively, the secondary battery 8203 may be provided in both the indoor unit 8200 and the outdoor unit 8204. The air conditioner may receive power supply from a commercial power source or use power stored in the secondary battery 8203.

[0392] exist Fig.26 In the embodiment, the electric refrigerator-freezer 8300 is an example of an electronic device using a secondary battery 8304. Specifically, the electric refrigerator-freezer 8300 includes a housing 8301, a refrigerator door 8302, a freezer door 8303, and a secondary battery 8304. Fig.26 In the embodiment, the secondary battery 8304 is provided inside the housing 8301. The electric refrigerator-freezer 8300 can receive power supply from a commercial power source, or can use power stored in the secondary battery 8304.

[0393] In addition, during the time period when the electronic device is not used, especially during the time period when the ratio of the actual amount of power used to the total amount of power that can be supplied by the commercial power supply source (called the power usage rate) is low, the power is stored in the secondary battery, thereby suppressing the increase of the power usage rate in the time period other than the above time period. For example, in the case of an electric refrigerator-freezer 8300, power is stored in the secondary battery 8304 at night when the temperature is low and the refrigerator door 8302 or the freezer door 8303 is not opened and closed. In addition, during the daytime when the temperature is high and the refrigerator door 8302 or the freezer door 8303 is opened and closed, the secondary battery 8304 is used as an auxiliary power source, thereby suppressing the power usage rate during the daytime.

[0394] The secondary battery is not limited to being installed in the above-mentioned electronic devices, but can also be installed in all electronic devices. By adopting one embodiment of the present invention, the cycle characteristics of the secondary battery can be improved. Therefore, by installing a microprocessor (including APS) that controls the charging of one embodiment of the present invention in the electronic device described in this embodiment, an electronic device with a longer service life can be achieved. This embodiment can be implemented in combination with other embodiments as appropriate.

[0395] first, FIG. 27A to FIG. 27E An example of an electronic device in which a power storage system according to one embodiment of the present invention is installed is shown. Examples of electronic devices to which a power storage system according to one embodiment of the present invention is applied include television devices (also referred to as televisions or television receivers), displays for computers, etc., digital cameras, digital video cameras, digital photo frames, mobile phones (also referred to as mobile phones, mobile phone devices), portable game consoles, portable information terminals, sound reproduction devices, and large-scale game machines such as pinball machines.

[0396] Fig.27A An example of a mobile phone is shown. The mobile phone 7400 includes an operation button 7403, an external connection port 7404, a speaker 7405, a microphone 7406, and the like in addition to a display unit 7402 assembled in a housing 7401. In addition, the mobile phone 7400 includes a power storage system according to one embodiment of the present invention. The power storage system according to one embodiment of the present invention includes, for example, a storage battery 7407 and the battery control circuit shown in the above embodiment.

[0397] Fig.27B The figure shows a state where the mobile phone 7400 is bent. When the mobile phone 7400 is deformed by an external force and the entire mobile phone 7400 is bent, the storage battery 7407 provided inside the mobile phone 7400 may also be bent. In this case, it is preferable to use a flexible storage battery as the storage battery 7407. Fig.27C The flexible storage battery is shown in a bent state. The storage battery is electrically connected to a control circuit 7408. As the control circuit 7408, the battery control circuit described in the above embodiment mode can be used.

[0398] In addition, the flexible storage battery can also be assembled along the curved surfaces of the inner or outer walls of houses and buildings, or the interior or exterior decoration of cars.

[0399] Fig.27D An example of a bracelet-type display device is shown. A portable display device 7100 includes a housing 7101, a display unit 7102, operation buttons 7103, and a power storage system of one embodiment of the present invention. The power storage system of one embodiment of the present invention includes, for example, a storage battery 7104 and a battery control circuit described in the above embodiment.

[0400] Fig.27E The portable information terminal 7200 is an example of a wristwatch-type portable information terminal. The portable information terminal 7200 includes a housing 7201, a display portion 7202, a strap 7203, a buckle 7204, operation buttons 7205, an input / output terminal 7206, and the like.

[0401] Portable information terminal 7200 can execute various application programs such as mobile phone, e-mail, article reading and writing, music playing, network communication, computer games, etc.

[0402] The display surface of the display portion 7202 is curved, and display can be performed along the curved display surface. In addition, the display portion 7202 has a touch sensor, and operation can be performed by touching the screen with a finger or a stylus pen. For example, by touching an icon 7207 displayed on the display portion 7202, an application can be started.

[0403] In addition to time setting, operation button 7205 may have various functions such as power switch, wireless communication switch, setting and canceling silent mode, setting and canceling power saving mode, etc. For example, by using an operating system incorporated in portable information terminal 7200, the function of operation button 7205 can be freely set.

[0404] In addition, the portable information terminal 7200 can perform short-range wireless communication standardized by communication. For example, by communicating with a headset capable of wireless communication, a hands-free call can be made.

[0405] In addition, the portable information terminal 7200 has an input / output terminal 7206, and can directly send data to or receive data from other information terminals through a connector. In addition, charging can also be performed through the input / output terminal 7206. In addition, the charging operation can also be performed using wireless power supply without using the input / output terminal 7206.

[0406] The portable information terminal 7200 includes a power storage system according to one embodiment of the present invention. The power storage system includes a storage battery and the battery control circuit described in the above embodiment.

[0407] The portable information terminal 7200 preferably includes a sensor. For example, a fingerprint sensor, a pulse sensor, a human body sensor such as a temperature sensor, a touch sensor, a pressure sensor, an acceleration sensor, etc. are preferably installed as the sensor.

[0408] This embodiment mode can be combined with the description of other embodiment modes as appropriate.

[0409] (Implementation 7)

[0410] In this embodiment mode, the market image in which an OS transistor can be used is described.

[0411] <Market Image>

[0412] First, in Fig.28 The market image of where OS transistors can be used is shown in Fig.28 In the figure, area 801 indicates a product area (OS Display) that can be applied to a display (Display) using an OS transistor, area 802 indicates a product area (OS LSI analog) that can be applied to an LSI (Large Scale Integration) using an OS transistor for analog processing, and area 803 indicates a product area (OS LSI digital) that can be applied to an LSI using an OS transistor for digital processing. Fig.28 The three areas shown, area 801, area 802 and area 803, in other words, can be preferably applied to three large markets.

[0413] In addition, Fig.28 , region 804 represents an overlapping region between region 801 and region 802, region 805 represents an overlapping region between region 802 and region 803, region 806 represents an overlapping region between region 801 and region 803, and region 807 represents an overlapping region between region 801, region 802, and region 803.

[0414] In OS Display, for example, FET structures such as Bottom Gate OS FET (BG OSFET) and Top Gate OS FET (TG OS FET) can be preferably used. Note that Bottom Gate OS FET includes channel etched FET and channel protection FET. In addition, Top Gate OS FET includes TGSA (Top Gate Self-Aligned) FET.

[0415] In addition, in OS LSI analog and OS LSI digital, for example, a Gate Last type OS FET (GL OS FET) can be preferably used.

[0416] Note that the above transistors include a single gate structure transistor with one gate electrode, a dual gate structure transistor with two gate electrodes, or a transistor with three or more gate electrodes. In addition, among the dual gate structure transistors, it is particularly preferable to use an S-channel (surrounded channel) structure transistor.

[0417] In addition, as products included in OS Display (area 801), there are products using LCD (liquid crystal display), EL (Electro Luminescence), and LED (Light Emitting Diode) for display devices. In addition, it is also preferable to combine the above display devices with Q-Dot (Quantum Dot).

[0418] In this embodiment, EL includes organic EL and inorganic EL. In this embodiment, LED includes Micro LED, Mini LED and Macro LED. In this specification, the area of ​​a chip is sometimes 10000 μm. 2 The following light-emitting diodes are recorded as Micro LEDs, which means the chip area is greater than 10000μm 2 And 1mm 2 The following light-emitting diodes are recorded as Mini LEDs, which means the chip area is larger than 1mm 2 The light emitting diode is recorded as Macro LED.

[0419] In addition, products included in OS LSI analog (area 802) include sound source localization devices corresponding to various frequency ranges (for example, audible sounds with frequencies of 20 Hz to 20 kHz, or ultrasonic waves above 20 kHz, etc.) or battery control devices (battery control ICs, battery protection ICs, or battery management systems).

[0420] In addition, products included in OS LSI digital (area 803) include storage devices, CPU (Central Processing Unit) devices, GPU (Graphics Processing Unit) devices, FPGA (field-programmable gate array) devices, power devices, hybrid devices in which OS LSI and Si LSI are stacked or mixed, light-emitting devices, etc.

[0421] In addition, as products included in area 804, a display device including an infrared sensor or a near-infrared sensor in the display area, a signal processing device having a sensor with an OSFET, or an embedded biosensor device can be cited. In addition, as products included in area 805, a processing circuit including an A / D (Analog to Digital) conversion circuit, or an AI (Artificial Intelligence) device including the processing circuit can be cited. In addition, as products included in area 806, a display device applying PixelAI technology can be cited. In addition, in this specification, etc., PixelAI technology refers to a technology that utilizes a memory composed of an OSFET, etc. installed in a pixel circuit of a display.

[0422] In addition, as a product included in the area 807, a composite product that combines all the products included in the above-mentioned areas 801 to 806 can be mentioned.

[0423] A semiconductor device according to one embodiment of the present invention Fig.28 As shown, the present invention can be applied to various product areas. That is, the semiconductor device according to one embodiment of the present invention can be applied to many markets.

[0424] This embodiment mode can be implemented in combination with the configurations described in other embodiment modes as appropriate.

[0425] (Additional Notes on the Descriptions in This Manual, etc.)

[0426] Next, additional explanation will be given to the above-mentioned embodiments and the description of each configuration in the embodiments.

[0427] The structure described in each embodiment can be appropriately combined with the structure described in other embodiments to constitute one mode of the present invention. In addition, when a plurality of structural examples are described in one embodiment, these structural examples can be appropriately combined.

[0428] In addition, the content (or part thereof) described in a certain embodiment may be applied to other content (or part thereof) described in that embodiment and / or content (or part thereof) described in one or more other embodiments, the content (or part thereof) described in a certain embodiment may be combined with other content (or part thereof) described in that embodiment and / or content (or part thereof) described in one or more other embodiments, and the content (or part thereof) described in a certain embodiment may be used to replace other content (or part thereof) described in that embodiment and / or content (or part thereof) described in one or more other embodiments.

[0429] In addition, the contents described in the embodiments refer to the contents described in each embodiment with reference to each drawing or the contents described by the words described in the specification.

[0430] In addition, more figures can be formed by combining a figure (or part thereof) shown in a certain embodiment with other parts of the figure, other figures (or parts thereof) shown in the embodiment, and / or figures (or parts thereof) shown in one or more other embodiments.

[0431] In addition, in this specification, etc., the components are classified according to their functions and are represented as independent blocks in the block. However, sometimes it is difficult to distinguish the components according to their functions in an actual circuit, etc., or one circuit involves multiple functions or multiple circuits involve one function. Therefore, the blocks in the block diagram are not limited to the components described in the specification, but can be expressed in another way as appropriate according to the situation.

[0432] In addition, for the sake of convenience, in the drawings, the size, thickness of the layer or the area are arbitrarily shown. Therefore, the present invention is not limited to the size in the drawings. In addition, the drawings are schematically shown for the sake of clarity and are not limited to the shapes or values ​​shown in the drawings. For example, it may include the unevenness of the signal, voltage or current caused by noise, or the unevenness of the signal, voltage or current caused by time deviation.

[0433] In this specification, when describing the connection relationship of a transistor, it is described as "one of the source and the drain" (or the first electrode or the first terminal) or "the other of the source and the drain" (or the second electrode or the second terminal). This is because the source and the drain of the transistor change depending on the structure or operating conditions of the transistor. In addition, the source and the drain of the transistor can be appropriately replaced by the source (drain) terminal or the source (drain) electrode, etc., depending on the situation.

[0434] In addition, in this specification, the term "electrode" or "wiring" does not limit the function of its constituent elements. For example, sometimes an "electrode" is used as a part of a "wiring", and vice versa. Furthermore, the term "electrode" or "wiring" also includes the case where a plurality of "electrodes" or "wirings" are formed as one.

[0435] In addition, in this specification, etc., voltage and potential can be appropriately interchanged. Voltage refers to the potential difference between the potential and the reference potential. For example, when the reference potential is the ground voltage, voltage can be interchanged with potential. The ground potential does not necessarily mean 0V. In addition, potential is relative, and the potential supplied to wiring etc. sometimes changes according to the reference potential.

[0436] In addition, in this specification, the words "film" and "layer" may be interchanged depending on the situation or condition. For example, the term "conductive layer" may be replaced with the term "conductive film". Also, for example, the term "insulating film" may be replaced with the term "insulating layer".

[0437] In this specification, etc., a switch refers to an element having a function of controlling whether current flows by changing to a conductive state (on state) or a non-conductive state (off state). Alternatively, a switch refers to an element having a function of selecting and switching a path of current.

[0438] In this specification, etc., for example, the channel length refers to the distance between the source and the drain in the region where the semiconductor (or the portion of the semiconductor through which current flows when the transistor is in an on state) and the gate overlap or in the region where the channel is formed in a top view of the transistor.

[0439] In this specification, etc., for example, the channel width refers to the length of the region where the semiconductor (or the portion through which current flows in the semiconductor when the transistor is in the on state) and the gate overlap, or the portion where the source and drain face each other in the region where the channel is formed.

[0440] In this specification, "A and B are connected" includes not only the case where A and B are directly connected, but also the case where A and B are electrically connected. Here, "A and B are electrically connected" means that there is an object with some electrical function between A and B, and electrical signals can be transmitted and received between A and B.

[0441] [Example 1]

[0442] In this example, changes in the time required for CC charging and the time required for CV charging were measured when the voltage and temperature at the start of charging of the secondary battery were changed.

[0443] Fig.29A , Fig.29B , Fig. 30A and Fig. 30B The relationship between the time required for CC charging (hereinafter referred to as time Tccr) and the time required for CV charging (hereinafter referred to as time Tcvr) and the voltage at the start of charging (hereinafter referred to as voltage Vst) is shown. The upper limit voltage of CC charging is 4.2V.

[0444] Fig.29A The relationship between the time Tccr and the time Tcvr of the secondary battery and the voltage Vst is shown when the temperature of the secondary battery is 45° C. The voltage Vst also rises as the remaining capacity SOC increases. Therefore, a tendency is observed that the time Tccr is short when the voltage Vst is high.

[0445] In addition, in a voltage range where the voltage Vst is much lower than the upper limit voltage of charging, the change in the time Tcvr is small and stable, and thus a tendency of low dependence on the voltage Vst is observed. On the other hand, when the voltage Vst does not reach the upper limit voltage, in a range where the voltage Vst is high, a clear dependence is observed that the time Tcvr decreases as the voltage Vst increases.

[0446] Fig.29B , Fig. 30A and Fig. 30B The relationship between the time Tccr and the time Tcvr and the voltage Vst of the secondary battery is shown when the temperature of the secondary battery is 30° C., 25° C., and 10° C. It is observed that the range of the voltage Vst when the time Tccr is stable tends to narrow as the temperature decreases.

[0447] like Fig.29A , Fig.29B , Fig. 30A and Fig. 30B As shown, the time Tcvr is greatly affected by the temperature of the secondary battery and the time Tccr.

[0448] [Example 2]

[0449] In this embodiment, changes in the time Tccr and the time Tcvr required for charging the secondary battery due to cycles and the operation of charging the secondary battery were evaluated.

[0450] The secondary battery is subjected to a charge and discharge cycle. Fig.31A , Fig.31B and Fig. 31C The charging curves of the 61st, 62nd and 63rd cycles are shown respectively. Fig.31A , Fig.31B and Fig. 31C , the horizontal axis represents the charging capacity and the vertical axis represents the charging voltage.

[0451] A waveform indicating a micro short circuit was observed in the region surrounded by a dotted circle at the 63rd time.

[0452] In the 62nd cycle, which is the cycle immediately before the cycle in which the waveform indicating the micro short circuit is obtained, the time Tcvr, that is, the time required for constant voltage charging, becomes significantly longer than that in the 61st cycle. In addition, the time Tccr, that is, the constant current charging time, also becomes longer.

[0453] Fig.32 The time Tcvr and the time Tccr in the 60th to 64th charge and discharge cycles are shown. The horizontal axis represents the number of charge and discharge cycles and the vertical axis represents the time Tcvr and the time Tccr. In the previous cycle representing the cycle of the micro short circuit, it can be seen that the time Tcvr and the time Tccr increase.

[0454] [Explanation of symbols]

[0455] Hi: signal, I: current, IN: terminal, IN1: terminal, IN2: terminal, Iref: current, Iss1: current, Iss2: current, Iss3: current, Lo: signal, OUT: terminal, OUT2: terminal, Q: signal, QB: signal, RESET: signal, RESETB: signal, VB: voltage, VC: voltage, VR: voltage, Vdd: high potential signal, Vin: voltage, Vref1: voltage, Vref2: high potential signal, Vref3: high potential signal, t1: time, t2: time, t3: time, t4: time, 100: power storage device, 101: control circuit, 102: reference generation circuit, 103: timer circuit, 104: regulator, 105: power supply, 106: counter, 121: secondary battery, 131: resistor, 137: protection circuit, 140: transistor, 150: transistor, 152: transistor, 153: transistor, 156: coil, 160: capacitor, 161: capacitor, 162: switch, 163: constant current source, 164: comparator, 165: transistor, 166: switch, 167: constant current source, 168: switch, 169: switch, 170: constant current source, 171: comparator, 172: comparator, 173: constant current source, 174: capacitor, 175: capacitor, 178: NAND circuit, 179: NAND circuit, 181: transistor, 182: transistor, 183: transistor, 184: transistor, 185: transistor, 186: transistor, 187: transistor, 188: transistor, 190: transistor, 191: current supply unit, 192: current supply unit, 193: current supply unit, 194: transistor, 195: transistor, 196: transistor, 197: transistor.< / dosram> < / nosram>

Claims

1. A power storage device, comprising: a first circuit section; a second circuit section; a timer circuit section; and a secondary battery, wherein the timer circuit section includes a comparator and a capacitor, the first circuit section is configured to control charging of the secondary battery, the first circuit section is configured to supply a first signal indicating the start of the charging of the secondary battery to the timer circuit section, the second circuit section is configured to generate a first reference voltage and a first reference current corresponding to a reference time, the second circuit section is configured to supply the first reference voltage and the first reference current to the timer circuit section, and the second circuit section is configured to supply the first reference voltage to one of the non-inverting input terminal and the inverting input terminal of the comparator, the timer circuit section is configured to generate a voltage corresponding to the elapsed time from the start time of the charging of the secondary battery, the timer circuit section is configured to charge the capacitor with an electric charge corresponding to the product of the first reference current and the elapsed time, the timer circuit section is configured to supply the voltage to the other of the non-inverting input terminal and the inverting input terminal of the comparator, the comparator is configured to compare the first reference voltage and the voltage, the power storage device is configured to stop the charging of the secondary battery when the voltage exceeds the first reference voltage, wherein the second circuit section is configured to convert a digital signal supplied from the first circuit section and generate the first reference voltage, and the first reference voltage is an analog signal.

2. The power storage device according to claim 1, wherein the timer circuit section includes a first transistor, a channel formation region of the first transistor contains indium, zinc, and element M, the element M is one or more elements selected from aluminum, gallium, yttrium, copper, vanadium, beryllium, boron, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium, one of the non-inverting input terminal and the inverting input terminal of the comparator is electrically connected to one electrode of the capacitor, the other of the non-inverting input terminal and the inverting input terminal of the comparator is electrically connected to one of the source and the drain of the first transistor, and the power storage device is configured to hold one of the source and the drain of the first transistor at the first reference voltage by turning off the first transistor.

3. The power storage device according to claim 1, wherein the timer circuit section includes a second transistor, a channel formation region of the second transistor contains indium, zinc, and element M, the element M is one or more elements selected from aluminum, gallium, yttrium, copper, vanadium, beryllium, boron, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium, and one of the source and the drain of the second transistor is electrically connected to one electrode of the capacitor.

4. A method of operating a power storage device, the power storage device comprising: a first circuit section; a second circuit section; a timer circuit section; and a secondary battery, Wherein, the first circuit unit is configured to control the charging of the secondary battery. The method includes: A first step in which the second circuit unit generates a first reference voltage and a first reference current corresponding to a reference time; A second step in which the second circuit unit supplies the first reference voltage and the first reference current to the timer circuit unit, and the first reference voltage is supplied to one of the non-inverting input terminal and the inverting input terminal of a comparator provided in the timer circuit unit; A third step of starting the charging of the secondary battery by supplying current to the secondary battery; A fourth step in which the first circuit unit supplies a first signal indicating the start of the charging of the secondary battery to the timer circuit unit; A fifth step in which the timer circuit unit generates a voltage corresponding to the elapsed time from the start time of the charging of the secondary battery; A sixth step of supplying the voltage to the other of the non-inverting input terminal and the inverting input terminal of the comparator; A seventh step of comparing the first reference voltage and the voltage; and An eighth step of stopping the charging of the secondary battery when the voltage exceeds the first reference voltage, Wherein, the second circuit unit is configured to convert a digital signal supplied from the first circuit unit and generate the first reference voltage, And, the first reference voltage is an analog signal.

5. The method for operating an electrical storage device according to claim 4, Wherein, The timer circuit unit includes a capacitor, In the fifth step, the timer circuit unit charges the capacitor with an electric charge corresponding to the product of the first reference current and the elapsed time, And, the voltage corresponds to the potential difference between the electrodes at both ends of the capacitor.

6. The method for operating an electrical storage device according to claim 4, Wherein, The timer circuit unit includes a transistor, One of the non-inverting input terminal and the inverting input terminal of the comparator is electrically connected to one of the source and the drain of the transistor, In the third step to the seventh step, the transistor is turned off to maintain the first reference voltage supplied to one of the non-inverting input terminal and the inverting input terminal of the comparator, And, in the fifth step, the voltage is supplied to the other of the non-inverting input terminal and the inverting input terminal of the comparator.

7. The method for operating an electrical storage device according to claim 4, Wherein, The timer circuit unit includes a capacitor, Charging of the first reference current to the capacitor is started according to the first signal, And, the voltage corresponds to the potential difference between the electrodes at both ends of the capacitor.

8. A method for operating an electrical storage device, The electrical storage device Comprises: A first circuit unit; A second circuit unit; A timer circuit unit; A temperature sensor; And A secondary battery, Wherein, the first circuit unit includes an arithmetic circuit and a memory, The first circuit unit is configured to control the charging of the secondary battery, The method includes: A first step of starting the first charging of the secondary battery by supplying a first current to the secondary battery at a first time; A second step of ending the first charging by stopping the supply of the first current at a second time; A third step of supplying first data including the temperature measured by the temperature sensor, second data including the first time, and third data including the second time to the memory and storing them in the memory; A fourth step in which the arithmetic circuit in the first circuit section performs an arithmetic operation using the first data, the second data, and the third data to determine the amount of a first reference voltage; A fifth step in which the second circuit section generates the first reference voltage and a first reference current; A sixth step in which the second circuit section supplies the first reference voltage and the first reference current to the timer circuit section, and the first reference voltage is supplied to one of the non-inverting input terminal and the inverting input terminal of a comparator provided in the timer circuit section; A seventh step of starting the second charging of the secondary battery by supplying a second current to the secondary battery at a third time; An eighth step in which the first circuit section supplies a first signal indicating the start of the second charging of the secondary battery to the timer circuit section; A ninth step in which the timer circuit section generates a voltage corresponding to the elapsed time from the start time of the second charging of the secondary battery; A tenth step of supplying the voltage to the other of the non-inverting input terminal and the inverting input terminal of the comparator; An eleventh step of comparing the first reference voltage and the voltage; and A twelfth step of stopping the second charging of the secondary battery when the voltage exceeds the first reference voltage, wherein the first charging is CC charging and the second charging is CV charging, wherein the second circuit section is configured to convert a digital signal supplied from the first circuit section and generate the first reference voltage, and the first reference voltage is an analog signal.

9. The method for operating an electrical storage device according to claim 8, wherein, the timer circuit section includes a capacitor, in the eighth step, the timer circuit section charges the capacitor with an electric charge corresponding to the product of the first reference current and the elapsed time, and the voltage corresponds to the potential difference between the electrodes at both ends of the capacitor.

10. The method for operating an electrical storage device according to claim 8, wherein, the timer circuit section includes a transistor, one of the non-inverting input terminal and the inverting input terminal of the comparator is electrically connected to one of the source and the drain of the transistor, in the sixth step to the eleventh step, the transistor is turned off to maintain the first reference voltage supplied to one of the non-inverting input terminal and the inverting input terminal of the comparator, and in the ninth step, the voltage is supplied to the other of the non-inverting input terminal and the inverting input terminal of the comparator.

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