Power storage device

Abstract

To provide a power storage device and the like that consume less power, or a power storage device and the like having a high degree of integration.SOLUTION: There is provided a power storage device in which a first battery cell has a first electrode on a first substrate, a positive electrode active material layer on the first electrode, an electrolyte layer on the positive electrode active material layer, a negative electrode active material layer on the electrolyte layer, and a second electrode on the negative electrode active material layer, a comparator circuit has a first input terminal, a second input terminal, an output terminal, and a first transistor, the first transistor has an oxide semiconductor on the first substrate, a first insulator on the oxide semiconductor, and a gate electrode on the first insulator, the first electrode is electrically connected to a gate of the first transistor and the first input terminal, the comparator circuit has a function of outputting, from the output terminal to a control circuit, a first signal in response to a result of comparison between a potential of the first electrode and a desired reference potential, and the control circuit has a function of controlling charging of the first battery cell in response to the first signal.SELECTED DRAWING: Figure 9

Description

[Technical Field]

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

[0002] Note that one embodiment of the present invention is not limited to the above technical fields. The technical field relates to an article, a method, or a manufacturing method. is a process, machine, manufacture, or composition of matter. Therefore, one aspect of the present invention disclosed in this specification more specifically relates to The technical fields of the present invention include display devices, light-emitting devices, power storage devices, imaging devices, memory devices, and their driving Examples of the method include a method for operating the device and a method for manufacturing the device. [Background technology]

[0003] Energy storage devices (also called batteries or secondary batteries) are used in a wide range of applications, from small electronic devices to automobiles. As the range of applications for batteries expands, the use of multiple batteries Applications using multi-cell battery stacks with cells connected in series are increasing. It is available.

[0004] The storage device detects abnormalities during charging and discharging, such as over-discharging, over-charging, over-current, or short circuit. In this way, the circuit that protects and controls the battery is equipped with a circuit for charging and discharging. In order to detect abnormalities during power supply, data such as voltage and current is acquired. In this case, control such as stopping charging and discharging and cell balancing is performed based on the observed data. Do the following.

[0005] Patent Document 1 discloses a protection IC that functions as a battery protection circuit. In 1, multiple comparators are installed inside, and the reference voltage and the terminal where the battery is connected are compared. The paper discloses a protection IC that detects abnormalities during charging and discharging by comparing the voltage of the battery with that of the charger.

[0006] Patent Document 2 also describes a battery state detection device that detects minute short circuits in a secondary battery and a built-in battery The company discloses a battery pack that

[0007] In addition, Patent Document 3 discloses a protective semiconductor that protects a battery pack in which secondary battery cells are connected in series. An apparatus is disclosed. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] U.S. Patent Application Publication No. 2011-267726 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-66161 [Patent Document 3] Japanese Patent Application Laid-Open No. 2010-220389 Summary of the Invention [Problem to be solved by the invention]

[0009] One embodiment of the present invention is a novel battery control circuit, a battery protection circuit, a power storage device, a semiconductor device, a vehicle Another object of the present invention is to provide an electronic device or the like. battery control circuits, battery protection circuits, power storage devices, semiconductor devices, vehicles, electronic devices, etc. Another object of one embodiment of the present invention is to provide a highly integrated battery control circuit, One object is to provide a battery protection circuit, a power storage device, a semiconductor device, a vehicle, an electronic device, etc. do.

[0010] Note that the problems of one embodiment of the present invention are not limited to the above-listed problems. This does not preclude the existence of other problems. Problems not mentioned in this section are problems that a person skilled in the art would be able to solve by understanding the specification or can be derived from the descriptions in the drawings, etc., and can be extracted appropriately from these descriptions. One aspect of the present invention is to achieve at least one of the above-listed objects and / or other objects. It solves one problem. [Means for solving the problem]

[0011] One aspect of the present invention is a battery pack including a first substrate, a first battery cell, a comparison circuit, and a control circuit, The first battery cell includes a first electrode on a first substrate, a positive electrode active material layer on the first electrode, and a positive electrode active material layer an upper electrolyte layer, a negative electrode active material layer on the electrolyte layer, and a second electrode on the negative electrode active material layer; The comparator circuit has a first input terminal, a second input terminal, an output terminal, and a first transistor. The first transistor includes an oxide semiconductor on a first substrate, a first insulator on the oxide semiconductor, and a gate electrode on the first insulator, the first electrode being a gate of the first transistor and A comparator circuit electrically connected to the first input terminal compares the potential of the first electrode with a desired reference potential. and a function of outputting a first signal according to the result from the output terminal to the control circuit, and the control circuit The power storage device has a function of controlling charging of the first battery cell in response to a first signal.

[0012] In the above configuration, the second transistor and the capacitance element are included, one of the source and drain of the second transistor is electrically connected to the second input terminal; The other of the source and drain is electrically connected to one electrode of the capacitance element, and the second transistor The transistor preferably includes an oxide semiconductor.

[0013] In the above configuration, the output terminal is electrically connected to the source or drain of the first transistor. Preferably, the two are electrically connected.

[0014] In the above structure, the second transistor including an oxide semiconductor a third transistor connected to the source and drain of the second transistor and a capacitance element; One of the terminals of the transistor is electrically connected to the second input terminal and the gate of the third transistor. The other of the source and drain of the transistor is electrically connected to one electrode of the capacitor element. Preferably, the output terminal is electrically connected to the source or drain of the third transistor. I wish.

[0015] In the above structure, the second insulator on the gate electrode of the first transistor and the and a third electrode on the second insulator, the first electrode being located on the second insulator, and the first electrode and the third electrode being The electrodes each have a titanium compound, and the third electrode is a source or drain of the first transistor. It is preferable that the power supply is electrically connected to the power supply.

[0016] In the above configuration, the first transistor has a source electrode and a drain electrode. a first electrode, a source electrode of the first transistor, and a drain electrode of the first transistor; Preferably, the electrode and the cathode each contain a titanium compound.

[0017] In the above structure, the first electrode and the gate electrode of the first transistor are Each of them preferably contains a titanium compound.

[0018] In the above configuration, the second battery cell, the conversion circuit, the clock generation circuit, and the boost circuit and a voltage holding circuit, the first transistor having a back gate, and the conversion circuit 2. It has the function of converting the positive electrode potential of the battery cell and providing it to the clock generation circuit as a second signal. The clock generation circuit has the function of generating a third signal, which is a clock signal, using the second signal. the boost circuit has a function of generating a first potential using a third signal, and the voltage holding circuit has It is preferable that the back gate has a function of applying and maintaining the first potential.

[0019] In the above configuration, the first substrate is a glass substrate, a quartz substrate, a sapphire substrate, a ceramic substrate, or the like. The substrates are either rock substrates, metal substrates, semiconductor substrates, SOI substrates, or plastic substrates. It is preferable that

[0020] In the above configuration, the first substrate is a semiconductor substrate, and the first substrate has silicon. It is preferable to have a transistor in which a channel formation region is provided in the first substrate.

[0021] Alternatively, one embodiment of the present invention is a semiconductor device including a first substrate, an oxide semiconductor layer over the first substrate, a a first transistor having a first insulator and a gate electrode on the first insulator; a second insulator on the body, a first electrode on the second insulator, a positive electrode active material layer on the first electrode, and a positive electrode active material a first electrode having an electrolyte layer on the first electrode, an anode active material layer on the electrolyte layer, and a second electrode on the anode active material layer; a first battery cell and a third electrode on the second insulator, the third electrode being a solenoid of the first transistor; It is an electricity storage device electrically connected to the source or drain.

[0022] In the above configuration, the first electrode and the third electrode preferably contain a titanium compound. I wish.

[0023] In the above structure, the first transistor has a channel formation region containing an oxide semiconductor. It is preferable to do so.

[0024] In the above configuration, the fourth electrode on the third electrode and the second electrode sandwiched between the third electrode and the fourth electrode are and a third insulator, and the first electrode and the fourth electrode each have a titanium compound. preferable.

[0025] In the above configuration, the fourth electrode on the third electrode and the pressure sandwiched between the third electrode and the fourth electrode and a conductive layer, and the first electrode and the fourth electrode each preferably contain a titanium compound. I wish.

[0026] Alternatively, one aspect of the present invention is a semiconductor device comprising: a first substrate; and a source electrode and a drain electrode on the first substrate. , an oxide semiconductor on the source electrode and the drain electrode, a first insulator on the oxide semiconductor, a first transistor having a gate electrode on the first insulator; a first electrode on the first substrate; a positive electrode active material layer on the electrode; an electrolyte layer on the positive electrode active material layer; a negative electrode active material layer on the electrolyte layer; and a first battery cell having a second electrode on the negative electrode active material layer, and a source electrode, a drain electrode and the first electrode are each a power storage device having a titanium compound.

[0027] Alternatively, one embodiment of the present invention is a semiconductor device including a first substrate, a first battery cell, a comparison circuit, and a control circuit. , and a piezoelectric element, and the first battery cell has a first electrode on the first substrate and a positive electrode on the first electrode. an active material layer, an electrolyte layer on the positive electrode active material layer, a negative electrode active material layer on the electrolyte layer, and a negative electrode active material layer and a second electrode on the first transistor, and the comparison circuit includes a first transistor An oxide semiconductor on a first substrate, a first insulator on the oxide semiconductor, and a gate electrode on the first insulator. The piezoelectric element has a third electrode, a piezoelectric layer on the third electrode, and a fourth electrode on the piezoelectric layer. a first electrode electrically connected to the gate electrode of the first transistor; The circuit has a function of outputting a first signal to the control circuit according to a comparison result between the potential of the first electrode and a desired potential. the control circuit has a function of controlling charging of the first battery cell in response to the first signal. It is an electronic device.

[0028] In the above configuration, the first electrode and the third electrode each contain a titanium compound. It is preferable that:

[0029] Alternatively, one embodiment of the present invention is a display device including a first substrate, a first battery cell, a comparator circuit, a display unit, and a drive circuit. and an operating circuit, and the first substrate is a glass substrate, a quartz substrate, a sapphire substrate, a ceramic substrate, a substrate selected from a plate, a metal substrate, a semiconductor substrate, an SOI substrate, and a plastic substrate; The cell includes a first electrode on a first substrate, a positive electrode active material layer on the first electrode, and an electrolytic capacitor on the positive electrode active material layer. a negative electrode active material layer on the electrolyte layer; and a second electrode on the negative electrode active material layer. has a titanium compound, and the comparison circuit has a first transistor, an oxide semiconductor on a first substrate, a source electrode and a drain electrode on the oxide semiconductor, and a first insulator on the semiconductor substrate; and a gate electrode on the first insulator, The driver circuit is electrically connected to the gate of the transistor, and has the function of providing an image signal to the display unit. The driver circuit is an electronic device including a plurality of transistors including an oxide semiconductor.

[0030] Alternatively, one embodiment of the present invention provides a power supply including a first substrate, a first battery cell, a comparison circuit, and a control circuit, The first battery cell has a first electrode on a first substrate, a positive electrode active material layer on the first electrode, and a positive electrode an electrolyte layer on the active material layer, a negative electrode active material layer on the electrolyte layer, and a second electrode on the negative electrode active material layer; the first electrode comprises a titanium compound, and the comparison circuit has a first input terminal and a second input terminal an output terminal; and a first transistor, the first transistor being formed by an oxide film on a first substrate. a first oxide semiconductor, a source electrode and a drain electrode on the oxide semiconductor, and a second oxide semiconductor. an insulator and a gate electrode on the first insulator, the first input terminal being electrically connected to the gate electrode; the first electrode is electrically connected to the first input terminal, and the comparison circuit is a first signal corresponding to a comparison result between the potential and a desired reference potential, from the output terminal to the control circuit; The control circuit has a function of controlling charging of the first battery cell in response to the first signal. It is a power storage device with this function. [Effects of the Invention]

[0031] According to one embodiment of the present invention, a novel battery control circuit, a novel battery protection circuit, a power storage device, and a semiconductor According to one embodiment of the present invention, a device, a vehicle, an electronic device, and the like can be provided. low power battery control circuits, battery protection circuits, power storage devices, semiconductor devices, vehicles, electronic devices, etc. According to one embodiment of the present invention, a highly integrated battery control circuit, a battery A protection circuit, a power storage device, a semiconductor device, a vehicle, an electronic device, and the like can be provided.

[0032] The effects of one embodiment of the present invention are not limited to the effects listed above. This does not preclude the existence of other effects. Other effects may be affected by this item, as described below. The effects not mentioned in this section are obvious to a person skilled in the art from the description or can be derived from the descriptions in the drawings, etc., and can be extracted appropriately from these descriptions. One aspect of the present invention has at least the above-listed effects and / or other effects. Therefore, one aspect of the present invention is to provide the above-listed However, there are cases where the effect is not significant. [Brief explanation of the drawings]

[0033] [Figure 1] 1A and 1B are a top view and a cross-sectional view of a secondary battery according to one embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing one embodiment of the present invention. [Figure 3] FIG. 3 is a cross-sectional view showing one embodiment of the present invention. [Figure 4] FIG. 4 is a cross-sectional view showing one embodiment of the present invention. [Figure 5] FIG. 5 is a cross-sectional view showing one embodiment of the present invention. [Figure 6] FIG. 6 is a cross-sectional view showing one embodiment of the present invention. [Figure 7] 7A and 7B are cross-sectional views illustrating a transistor according to one embodiment of the present invention. [Figure 8] 8A and 8B are top views of a secondary battery according to one embodiment of the present invention. [Figure 9] FIG. 9 is a block diagram illustrating one embodiment of the present invention. [Figure 10] 10A and 10B are circuit diagrams illustrating one embodiment of the present invention. [Figure 11] FIG. 11 is a block diagram illustrating one embodiment of the present invention. [Figure 12]12A and 12B are block diagrams illustrating one embodiment of the present invention, and circuit diagrams illustrating one embodiment of the present invention. [Figure 13] 13A and 13B are circuit diagrams illustrating one embodiment of the present invention. [Figure 14] 14A, 14B, and 14C are circuit diagrams illustrating one embodiment of the present invention. [Figure 15] 15A and 15B are circuit diagrams illustrating one embodiment of the present invention. [Figure 16] FIG. 16 is a diagram illustrating an example of an electronic device. [Figure 17] Fig. 17A is a diagram illustrating an example of an electronic device, Fig. 17B is a diagram illustrating an example of an electronic device, and Fig. 17C is a diagram illustrating an example of an electronic device. [Figure 18] 18A and 18B are diagrams illustrating an example of an electronic device. [Figure 19] Fig. 19A is a diagram illustrating an example of an electronic device. Fig. 19B is a diagram illustrating an example of an electronic device. Fig. 19C is a diagram illustrating an example of an aircraft. Fig. 19D is a diagram illustrating an example of a vehicle. DETAILED DESCRIPTION OF THE INVENTION

[0034] Hereinafter, embodiments will be described with reference to the drawings. It is possible to implement the present invention in various ways without departing from the spirit and scope of the present invention. It will be readily apparent to those skilled in the art that various modifications may be made to the details of the present invention. However, the present invention should not be construed as being limited to the description of the following embodiments.

[0035] In this specification, the ordinal numbers "first," "second," and "third" refer to the constituent elements. The numbers are added to avoid confusion and do not limit the number of components. The order of the components is not limited. The element referred to as "first" in one embodiment may be used in other embodiments or in the claims. In addition, for example, the second component may be the component referred to as "second" in the specification. A component referred to as "first" in one embodiment may be used in other embodiments, or It may be omitted in the claims.

[0036] In the drawings, elements that are the same or have similar functions, elements that are made of the same material, or In some cases, the same reference numerals may be used to designate elements that are formed at the same time, and repeated explanations thereof will be omitted. It may be omitted.

[0037] In addition, the position, size, range, etc. of each component shown in the drawings etc. are to be clearly indicated in order to facilitate understanding of the invention. Therefore, the actual location, size, range, etc. may not be shown. The invention is not necessarily limited to the position, size, range, etc. disclosed in the drawings, etc. For example, in the actual manufacturing process, resist masks and other materials may be damaged unintentionally by etching or other processes. However, this may not be reflected in the diagram to make it easier to understand.

[0038] Also, in top views (also called "plan views") and perspective views, etc., the drawings are easy to understand. Therefore, descriptions of some components may be omitted.

[0039] In addition, the terms "electrode" and "wiring" used in this specification and the like refer to these components functionally. This is not a limitation. For example, an "electrode" may be used as part of a "wiring." , and vice versa. Furthermore, the terms "electrode" and "wiring" may be used interchangeably with "electrodes" and "wiring." This also includes cases where the wiring is formed integrally.

[0040] In this specification, a "terminal" refers to, for example, a wiring or an electrode connected to a wiring. In addition, in this specification, a part of the "wiring" may be referred to as a "terminal." .

[0041] In this specification, the terms "above" and "below" refer to the positional relationship of components directly above or below each other. It is not limited to being directly under and in direct contact with the insulating layer A. If the expression is "electrode B", electrode B does not need to be formed directly on insulating layer A, This does not exclude the inclusion of other components between the insulating layer A and the electrode B.

[0042] The source and drain functions may also be different when using transistors with different polarities. When the direction of current changes during circuit operation, they may be interchanged depending on the operating conditions. Therefore, it is difficult to determine which is the source and which is the drain. In this specification, the terms source and drain can be used interchangeably. It shall be.

[0043] In addition, in this specification, "electrically connected" refers to a direct connection and a connection without any This includes cases where the device is connected via "something that has an electrical effect." "Something with an electrical effect" means something that enables the transmission and reception of electrical signals between connected objects. Therefore, even if it is expressed as "electrically connecting," In real circuits, there are cases where there are no physical connections and only wires are extended. do.

[0044] In this specification, "parallel" means that two lines are at an angle of -10° to 10°. This refers to the state in which the object is arranged at an angle between -5° and 5°. Also, "perpendicular" and "orthogonal" mean, for example, that two straight lines are at an angle of 80° or more and 100° or less. This refers to a state in which the object is arranged at an angle between 85° and 95°.

[0045] In this specification and elsewhere, counting values ​​and measurement values ​​are referred to as "the same," "the same," "etc." When we say "good" or "uniform," we mean plus or minus 2 unless otherwise specified. It is assumed that there is a 0% margin of error.

[0046] In this specification, when etching is performed after forming a resist mask, Unless otherwise specified, the resist mask is removed after the etching process is completed. do.

[0047] Also, a voltage is a potential between a certain potential and a reference potential (for example, a ground potential or a source potential). Therefore, voltage and potential can be used interchangeably. many.

[0048] Even when written as "semiconductor," if the conductivity is sufficiently low, it may be called an "insulator." Therefore, it is possible to use "semiconductor" instead of "insulator." In this case, the boundary between "semiconductor" and "insulator" is vague, and it is difficult to make a strict distinction between the two. Therefore, the terms "semiconductor" and "insulator" in this specification can be read interchangeably. It may be possible.

[0049] Also, even if a material is written as a "semiconductor," if the material has a sufficiently high conductivity, it may be written as a "conductor." Therefore, it is possible to use "semiconductor" instead of "conductor." In this case, the boundary between "semiconductor" and "conductor" is vague, and it is difficult to make a strict distinction between the two. Therefore, the terms "semiconductor" and "conductor" in this specification can be read interchangeably. It may be possible.

[0050] In this specification, the "on state" of a transistor refers to the state where the source of the transistor is This refers to a state in which the drain and the gate are considered to be electrically short-circuited (also called the "conducting state"). The "off state" of a transistor means that the source and drain of the transistor are electrically isolated. This refers to a state in which the circuit is considered to be disconnected (also called a "non-conducting state").

[0051] In this specification, the term "on-state current" refers to the amount of current that flows through the source when a transistor is in an on-state. The term "off-state current" may refer to the current that flows between the gate and drain of a transistor. It may refer to the current that flows between the source and drain when the device is in the off state.

[0052] In this specification and the like, a high power supply potential VDD (hereinafter simply referred to as "VDD" or "H potential" ") refers to a power supply potential that is higher than the low power supply potential VSS. The potential VSS (hereinafter simply referred to as "VSS" or "L potential") is the potential higher than the high power supply potential VDD. Also, the ground potential can be used as VDD or VSS. For example, if VDD is at ground potential, VSS is at a potential lower than ground potential, If VSS is at ground potential, VDD is at a potential higher than ground potential.

[0053] In this specification, the term "gate" refers to a gate electrode and a part or all of a gate wiring. The gate wiring is the part that is connected to the gate electrode of at least one transistor and another This refers to wiring that electrically connects electrodes or other wiring.

[0054] In this specification, the source includes a source region, a source electrode, and a source wiring. The source region is the part of the semiconductor layer where the resistivity is below a certain value. The source electrode refers to the conductive layer connected to the source region. The source wiring is a wiring that connects the source electrode of at least one transistor with another electrode or another wiring. This refers to wiring that electrically connects wires.

[0055] In this specification, the drain includes a drain region, a drain electrode, and a drain electrode. The drain region is a part or all of the semiconductor layer that has a certain resistivity. The drain electrode is the conductive area connected to the drain region. The drain wiring is a layer that connects at least one transistor drain electrode and This refers to wiring for electrically connecting to another electrode or another wiring.

[0056] (Embodiment 1) A secondary battery of one embodiment of the present invention will be described with reference to FIG.

[0057] [Secondary battery configuration]

[0058] 1A and 1B show a specific example of a secondary battery 200 according to one embodiment of the present invention. A secondary battery 200 formed on a substrate 110 will now be described.

[0059] FIG. 1A is a top view, and FIG. 1B is a cross-sectional view taken along line A-A' in FIG. 1A. The battery 200 is a thin-film battery, and as shown in FIG. 1B, a cathode 100 and a solid electrolyte are disposed on a substrate 110. A stack of solid electrolyte layers 203 is formed, and a negative electrode 210 is formed on the solid electrolyte layer 203. The electrode 100 has a positive electrode current collector 103 and a positive electrode active material layer 101 on the positive electrode current collector 103. The negative electrode 210 includes a negative electrode active material layer 204 and a negative electrode current collector 205 on the negative electrode active material layer 204. The solid electrolyte layer 203 is provided between the positive electrode active material layer 101 and the negative electrode active material layer 204. can be done.

[0060] The secondary battery 200 also includes a positive electrode 100, a solid electrolyte layer 203, and a protective layer on the negative electrode 210. Preferably, layer 206 is formed.

[0061] The films forming these layers can be formed using metal masks. The positive electrode current collector 103, the positive electrode active material layer 101, the solid electrolyte layer 203, and the negative electrode active material layer 104 are formed by sputtering. The material layer 204 and the negative electrode current collector 205 can be selectively formed. Alternatively, the solid electrolyte layer 203 may be selectively formed using a metal mask.

[0062] As shown in FIG. 1A, a part of the negative electrode current collector 205 is exposed to form a negative electrode terminal portion. In addition, a part of the positive electrode current collector 103 is exposed to form a positive electrode terminal. The area other than the positive electrode terminal portion is covered with a protective layer 206.

[0063] It is preferable to use a conductive material for the positive electrode current collector 103. It is preferable to use a material that is easy to control. For example, titanium compounds such as titanium oxide and titanium nitride Tantalum, titanium oxide partially substituted with nitrogen, titanium nitride partially substituted with oxygen, or titanium oxide Titanium nitride (TiO (X) N y , 0 < x < 2, 0 < y < 1), etc. can be applied. Among them titanium nitride is particularly preferable because it has high conductivity and a high function of suppressing oxidation. By using titanium nitride it may be possible to stabilize the crystal structure of the positive electrode active material layer 101 .

[0064] Also, a laminated structure may be used for the positive electrode current collector 103. For example, a first layer having a material such as a metal like gold, platinum, aluminum nium, titanium, copper, magnesium, iron, cobalt, nickel, zinc, germanium, indium dium, silver, palladium, etc., and an alloy thereof may be provided, and a second layer having a titanium compound may be provided by laminating it on the first layer [[ID=2​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​ The solid electrolyte layer 203 may have a laminated structure. When the solid electrolyte layer 203 is a laminated structure, lithium phosphate is contained in one layer. (Li3PO4) with nitrogen added (Li3PO (4-Z) N Z : Also called LiPON It is also possible to stack two layers (which can be seen in the figure). Note that Z>0.

[0067] The solid electrolyte layer 203 can be formed by, for example, a sputtering method.

[0068] The positive electrode active material layer 101 contains lithium, a transition metal M, and oxygen. It can be said that O1 has a composite oxide containing lithium and a transition metal M.

[0069] The transition metal M contained in the positive electrode active material layer 101 is, together with lithium, a metal in the space group R-3m. It is preferable to use a metal that can form a layered rock salt type composite oxide, which belongs to the transition metal M. For example, one or more of manganese, cobalt, and nickel can be used. That is, the positive electrode active material layer 101 may contain only cobalt as a transition metal. Nickel alone may be used, or two types of cobalt and manganese, or cobalt and nickel Two types may be used, or three types of cobalt, manganese, and nickel may be used. The electrode active material layer 101 is made of lithium cobalt oxide, lithium nickel oxide, and manganese oxide. Lithium cobalt oxide substituted with nickel, cobalt partially substituted with nickel lithium manganese cobalt oxide, lithium manganese cobalt oxide, etc. The composite oxide may include:

[0070] In addition to the above, the positive electrode active material layer 101 contains magnesium, fluorine, aluminum, and other The positive electrode active material layer 10 may contain elements other than the transition metal M. In other words, the positive electrode active material layer 101 may further stabilize the crystal structure of the magnesium. lithium cobalt oxide doped with neodymium and fluorine, and magnesium and fluorine doped lithium nickel-cobalt oxide, magnesium and fluorine doped cobalt oxide lithium nickel-cobalt-aluminate, lithium nickel-cobalt-aluminate, magnesium and fluorine-doped nickel-cobalt-lithium aluminum oxide. It is possible.

[0071] The positive electrode active material layer 101 is made of lithium, cobalt, nickel, aluminum, magnesium, When oxygen and fluorine are contained, the atomic ratio of cobalt contained in the positive electrode active material layer 101 is 10 When the atomic ratio of nickel is 0, it is preferable that the atomic ratio is, for example, 0.05 or more and 2 or less, and 0.1 or more and 1 The positive electrode active material layer 101 is preferably 0.5 or less, and more preferably 0.1 or more and 0.9 or less. When the atomic ratio of cobalt in the alloy is 100, the atomic ratio of aluminum is, for example, 0.0. Preferably, the ratio is 5 or more and 2 or less, more preferably 0.1 or more and 1.5 or less, and even more preferably 0.1 or more and 0.9 or less. When the atomic ratio of cobalt contained in the positive electrode active material layer 101 is 100, The atomic ratio of magnesium is preferably, for example, 0.1 or more and 6 or less, and more preferably 0.3 or more and 3 or less. In addition, when the atomic ratio of magnesium contained in the positive electrode active material layer 101 is 1, The atomic ratio of fluorine is preferably, for example, 2 or more and 3.9 or less.

[0072] By having nickel, aluminum and magnesium in the above concentrations, high voltage This allows the battery to maintain a stable crystal structure even after repeated charging and discharging at high pressure. This allows the positive electrode active material layer 101 to have excellent charging cycle characteristics.

[0073] The molar concentrations of cobalt, nickel, aluminum and magnesium are determined, for example, by inductive coupling protons. The molar concentration of fluorine can be evaluated by inductively coupled plasma mass spectrometry (ICP-MS). For example, it can be evaluated by glow discharge mass spectrometry (GD-MS).

[0074] For example, a composite oxide having a spinel crystal structure can be used as the positive electrode active material. In addition, for example, a polyanion-based material can be used as the positive electrode active material. Examples of rhythmium anion materials include materials with an olivine-type crystal structure and Nasicon-type materials. In addition, for example, a material containing sulfur can be used as the positive electrode active material. can.

[0075] As a material having a spinel-type crystal structure, for example, a composite represented by the general formula LiM2O4 is used. In the above general formula LiM2O4, Mn is used as the element M. For example, LiMn2O4 can be used. In iM2O4, by containing Ni in addition to Mn as the element M, This is preferable because it may improve the discharge voltage and energy density. Lithium-containing materials with spinel-type crystal structure containing manganese, such as O4, are mixed with a small amount of nickel. Lithium kerate (LiNiO2 and LiNi 1-x M x Mixing O2 (M=Co, Al, etc.) This is preferable because it is possible to improve the characteristics of the secondary battery.

[0076] As a polyanion-based material, for example, a composite oxide having oxygen, metal A, metal M, and element Z can be used. Metal A in the polyanion-based material is one or more of Li, Na, and Mg, and metal M in the polyanion-based material is one or more of Fe, Mn, Co, Ni, Ti, V, and Nb, and element Z is one or more of S, P, Mo, W, As, and Si. As a material having an olivine-type crystal structure, for example, a composite material (general formula LiMPO4 (M is one or more of Fe(II), Mn(II), Co(II), and Ni(II))) can be used. Representative examples of the general formula LiMPO4 include LiFePO4, LiNiPO4,

[0077] LiCoPO⁴, LiMnPO⁴, LiFe Ni PO⁴, LiFe Co a Ni b PO⁴, LiFe a Co b PO⁴, LiFe a Mn b PO⁴, LiNi a Co b PO⁴, LiNi <000003{34}>Mn b PO⁴ (a + b is 1 or less, 0 < a < 1, 0 < b < 1), LiFe c Ni d Co e PO⁴, LiFe c Ni d Mn e PO⁴, LiNi c Co d Mn e PO⁴ (c + d + e is 1 or less, 0 < c < 1, 0 < f Ni g Co h Mn i PO⁴ (f + g + h + i is 1 or less , 0 < f < 1, 0 < g < 1, 0 < h < 1, 0 < i < 1), etc. Lithium compounds can be used. can be done.

[0078] Also, the general formula Li (2-j) MSiO4 (M is Fe(II), Mn(II), Co( A composite material such as one or more of Ni(II), Ni(II), 0≦j≦2) can be used. Formula Li (2-j) A typical example of MSiO4 is Li (2-j) FeSiO4, Li (2 -j) NiSiO4, Li (2-j) CoSiO4, Li (2-j) MnSiO4, Li (2-j) Fe k Ni l SiO4, Li (2-j) Fe k Co l SiO4, Li (2-j ) Fe k Mn l SiO4, Li (2-j) Ni k Co l SiO4, Li (2-j) Ni k Mn l SiO4 (k+l is 1 or less, 0 <k<1、0<l<1)、Li (2-j) Fe m N i n Co q SiO4, Li (2-j) Fe m Ni n Mn q SiO4, Li (2-j) Ni m Co n Mn q SiO4 (m+n+q is 1 or less, 0 <m<1、0<n<1、0<q<1) , Li (2-j) Fe r Ni s Co t Mn u SiO4 (r+s+t+u is less than 1, 0 <r <1、0<s<1、0<t<1、0<u<1) and other lithium compounds can be used as materials and it is possible.

[0079] Also, A x M2(XO4)3 (A = Li, Na, Mg, M = Fe, Mn, Ti, V, N b, X = S, P, Mo, W, As, Si) and a NASICON-type compound represented by the general formula can be used as the NASICON-type compound, there are Fe2(MnO4)3, Fe2(SO4)3 , Li3Fe2(PO4)3, etc. Also, as the positive electrode active material, compounds represented by the general formula Li2MPO4F, L i2MP2O7, Li5MO4 (M = Fe, Mn) can be used and it is possible.

[0080] ​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​Na3V2(PO4)3, Na2FePO4F, NaVPO4F, NaMPO4 (M is Fe(II), Mn(II), Co(II), Ni(II)), Na2FePO4F, N Sodium-containing oxides such as a4Co3(PO4)2P2O7 are used as the positive electrode active material. That's fine.

[0083] Alternatively, a lithium-containing metal sulfide may be used as the positive electrode active material. For example, Li2T Examples include iS3 and Li3NbS4.

[0084] As a positive electrode active material according to one embodiment of the present invention, a mixture of two or more of the above-mentioned materials is used. That's fine.

[0085] The negative electrode active material layer 204 may be made of silicon, carbon, titanium oxide, vanadium oxide, indium oxide, or the like. Sodium oxide, zinc oxide, tin oxide, nickel oxide, etc. can be used. Materials that can be alloyed with Li, such as lithium and aluminum, can be used. Metal oxides such as lithium titanium oxide (Li4Ti5O 12 , Li Among them, silicon and oxide may be used as the negative electrode active material layer 204. Materials containing silicon (SiO x It is preferable to use a negative electrode active material layer 20. Li metal may also be used as 4.

[0086] In the secondary battery 200, a positive electrode, a solid electrolyte layer, and a negative electrode are stacked as a set. By layering and connecting them in series, the voltage of the secondary battery may be increased.

[0087] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0088] (Embodiment 2) In this embodiment, a structural example of a power storage device of one embodiment of the present invention will be described.

[0089] A power storage device of one embodiment of the present invention includes a secondary battery and a battery control circuit. The circuit has a function of protecting the secondary battery, for example. The battery control circuit has a function of controlling the charging of the secondary battery. It has the function of viewing.

[0090] A battery control circuit according to one embodiment of the present invention includes a transistor having an oxide semiconductor in a channel formation region. It is preferable that the power transistor have an OS transistor. The battery control circuit according to one embodiment of the present invention includes an OS transistor. In addition to the transistor, the channel formation region is made of silicon, germanium, or silicon germanium. The semiconductor device may have transistors with silicon, silicon carbide, etc.

[0091] 2 illustrates a configuration example that can be applied to a power storage device of one embodiment of the present invention. , a secondary battery 200, and a transistor 500 which is an OS transistor included in the battery control circuit. 2 shows an example in which the secondary battery is stacked on the substrate 599. Although an example in which one secondary battery is provided is shown, two or more secondary batteries may be provided on the substrate 599. In such a case, for example, either the positive electrode or the negative electrode may be used in common. It is preferable to use common materials for the positive electrode, negative electrode, electrolyte, etc.

[0092] The substrate 599 may be a glass substrate, a quartz substrate, a sapphire substrate, a ceramic substrate, or a metal substrate. Plates (e.g., stainless steel substrates, substrates with stainless steel foil, tungsten substrate, tungsten foil substrate, etc.), semiconductor substrate (e.g., single crystal Semiconductor substrate, polycrystalline semiconductor substrate, or compound semiconductor substrate) SOI (SOI: Sil icon on insulator substrate, plastic substrate, etc. can be used. The substrate may be a flexible substrate, a laminated film, paper containing fibrous materials, or A flexible substrate, a laminated film, a base film, etc. can be used. Examples of films include polyethylene terephthalate. Polyethylene naphthalate (PET), Polyethersulfone (PES) ), and polytetrafluoroethylene (PTFE) are typical plastics. For example, synthetic resin such as acrylic resin is used. Examples include polyethylene, polyester, polyvinyl fluoride, and polyvinyl chloride. Examples include polyamide, polyimide, aramid resin, epoxy resin, and inorganic vapor deposition film. , or paper, etc.

[0093] In FIG. 2, an insulator 514 is provided on a substrate 599. The insulator 514 is made of water. It is preferable to use a film having a barrier property that prevents diffusion of atoms and impurities. Examples of 4 include silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, etc. Silicon, aluminum oxide, aluminum oxynitride, aluminum nitride oxide, aluminum nitride Niu can be used.

[0094] In this specification, silicon oxynitride refers to a material having a higher content of oxygen than nitrogen in its composition. Silicon nitride oxide refers to a material that contains more nitrogen than oxygen. In this specification, aluminum oxynitride refers to a material with a high content. Aluminum oxide nitride is a material that has a higher oxygen content than nitrogen. It refers to a material that contains more nitrogen than oxygen as a constituent.

[0095] <Transistor 500> The transistor 500 includes an oxide 530 including a channel formation region, and an oxide semiconductor It is preferable to use a functional metal oxide. For example, the oxide 530 is In-M- Zn oxide (element M is aluminum, gallium, yttrium, copper, vanadium, beryl Sodium, boron, titanium, iron, nickel, germanium, zirconium, molybdenum, la tantalum, cerium, neodymium, hafnium, tantalum, tungsten, or magnesium It is preferable to use a metal oxide such as one or more selected from the following.

[0096] Specifically, the oxide 530a is composed of In:Ga:Zn=1:3:4 [atomic ratio], Alternatively, a metal oxide having an atomic ratio of 1:1:0.5 may be used. In:Ga:Zn=4:2:3 [atomic ratio] or 1:1:1 [atomic ratio] The oxide 530c may be a metal oxide of In:Ga:Zn=1:3:4. [atomic ratio], Ga:Zn=2:1 [atomic ratio], or Ga:Zn=2:5 [atomic ratio] In addition, a specific example of the oxide 530c having a stacked structure is as follows: The atomic ratios are In:Ga:Zn=4:2:3 and In:Ga:Zn=1:3:4. [Atomic ratio] Ga:Zn=2:1 [Atomic ratio] and In:Ga:Zn=4 :2:3 [atomic ratio], Ga:Zn=2:5 [atomic ratio], and In:Ga: Zn=4:2:3 [atomic ratio], gallium oxide and In:Ga:Zn=4: Examples include a layered structure with an atomic ratio of 2:3.

[0097] The oxide 530b may be crystalline. For example, the oxide 530b may be crystalline. S(c-axis aligned crystalline oxide semic It is preferable to use a crystalline oxide such as CAAC-OS. The material has few impurities and defects (such as oxygen vacancies), and has a highly crystalline, dense structure. Therefore, the extraction of oxygen from the oxide 530b by the source or drain electrode In addition, even if a heat treatment is performed, oxygen is not removed from the oxide 530b. Since the transistor 500 can be manufactured at high temperatures ( It is stable against the so-called thermal budget.

[0098] The metal oxide that functions as the channel forming region in the oxide 530 is a band gap metal oxide. It is preferable to use a material with a peak voltage 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 a transistor can be reduced. It is possible.

[0099] The oxide 530 has an oxide 530a under the oxide 530b, so that the oxide 530a The diffusion of impurities from structures formed below the oxide 530b can be suppressed. In addition, by having the oxide 530c on the oxide 530b, the oxide 530c can be formed. Therefore, the diffusion of impurities from the structure formed above into the oxide 530b can be suppressed. do.

[0100] The oxide 530 has a laminated structure of a plurality of oxide layers with different atomic ratios of each metal atom. Specifically, in the metal oxide used for the oxide 530a, it is preferable to use The atomic ratio of element M in the metal oxide used for oxide 530b is It is preferable that the atomic ratio of the metal oxide used for the oxide 530a is larger than that of the element M. In the oxide 530b, the atomic ratio of element M to In is In the oxide 530b, the atomic ratio of the element M to In is preferably larger than that of the element M. In the metal oxide used for the oxide 530a, the atomic ratio of In to the element M is In the metal oxide, the atomic ratio of In to the element M is preferably larger than that of In. , oxide 530c can be oxide 530a or oxide 530b. Things can be used.

[0101] The energy of the conduction band minimum of the oxide 530a and the oxide 530c is It is preferable that the energy of the oxide is higher than the energy of the bottom of the conduction band of oxide b. The electron affinity of oxide 530a and oxide 530c is smaller than that of oxide 530b. It is preferable that:

[0102] Here, at the junctions of the oxide 530a, the oxide 530b, and the oxide 530c, The energy level of the lower conduction band edge changes gradually. The energy levels of the conduction band minimum at the junction of 530b and oxide 530c are continuous. In order to achieve this, the oxide 530 The interface between oxide 530a and oxide 530b, and the interface between oxide 530b and oxide 530c are It is preferable to lower the defect level density of the resulting mixed layer.

[0103] Specifically, oxide 530a and oxide 530b, and oxide 530b and oxide 530c are By having a common element other than oxygen (as the main component), a mixed layer with low defect level density is formed. For example, when the oxide 530b is an In-Ga-Zn oxide, the oxide 530a and oxide 530c are In-Ga-Zn oxide, Ga-Zn oxide, oxide Gallium or the like may be used.

[0104] At this time, the main path of the carriers is the oxide 530b. By configuring the oxide 530c as described above, the interface between the oxide 530a and the oxide 530b and the oxide The defect state density at the interface between the substrate 530b and the oxide 530c can be reduced. Therefore, the influence of interface scattering on carrier conduction is reduced, and the transistor 500 has a high On-current can be obtained.

[0105] On the oxide 530b, a conductor 542a is formed, which functions as a source electrode and a drain electrode. The conductors 542a and 542b are provided. Aluminum, chromium, copper, silver, gold, platinum, tantalum, nickel, titanium, molybdenum, ungsten, hafnium, vanadium, niobium, manganese, magnesium, zirconium , beryllium, indium, ruthenium, iridium, strontium, and lanthanum The metal elements mentioned above, or alloys containing the above metal elements, or combinations of the above metal elements It is preferable to use an alloy of tantalum nitride, titanium nitride, tungsten nitride, etc. titanium and aluminum nitrides, tantalum and aluminum nitrides, and titanium oxides Ruthenium, ruthenium nitride, oxides containing strontium and ruthenium, lanthanum and nickel It is preferable to use oxides containing titanium. Nitrides containing tantalum and aluminum, nitrides containing tantalum and aluminum, ruthenium oxide , ruthenium nitride, oxides containing strontium and ruthenium, oxides containing lanthanum and nickel Oxides are conductive materials that are resistant to oxidation or that maintain conductivity even after absorbing oxygen. Furthermore, metal nitride films such as tantalum nitride have low resistance to hydrogen or oxygen. It is preferable because it has barrier properties.

[0106] In addition, although the conductor 542a and the conductor 542b are shown as single-layer structures in FIG. 2, For example, a tantalum nitride film and a tungsten film may be stacked. Alternatively, a titanium film and an aluminum film may be stacked on a tungsten film. A two-layer structure in which a copper film is laminated on a copper-magnesium-aluminum alloy film. Two-layer structure with a copper film layered on a titanium film, two-layer structure with a copper film layered on a tungsten film It may have a two-layer structure.

[0107] Also, a titanium film or titanium nitride film and an aluminum film overlaid on the titanium film or titanium nitride film are used. A three-layer structure in which a titanium film or a copper film is laminated and a titanium film or a titanium nitride film is further formed on top of that. Molybdenum film or molybdenum nitride film and a An aluminum film or a copper film is laminated on top of it, and a molybdenum film or a molybdenum nitride film is further laminated on top of it. There are three-layer structures that form a transparent film. Transparent conductive materials may also be used.

[0108] 2, the oxide 530 is formed at the boundary with the conductor 542a (conductor 542b). In the case where a region 543a and a region 543b are formed as low resistance regions on the surface and in the vicinity thereof, In this case, the region 543a functions as either a source region or a drain region. The region 543b functions as the other of the source region and the drain region. A channel forming region is formed in the region sandwiched between region 543a and region 543b.

[0109] By providing the conductor 542a (conductor 542b) so as to be in contact with the oxide 530, The oxygen concentration in the region 543a (region 543b) may decrease. The metal contained in the conductor 542a (conductor 542b) and the oxide 530 are In such a case, a metal compound layer containing the component may be formed in the region 543a (region The carrier density in the region 543a (region 543b) increases, and the region 543a (region 543b) becomes a low resistance region. become.

[0110] The insulator 544 is provided to cover the conductor 542a and the conductor 542b. The insulator 544 prevents oxidation of the oxide 542a and the conductor 542b. 30 and may be provided so as to be in contact with the insulator 524.

[0111] Insulator 544 includes hafnium, aluminum, gallium, yttrium, and zirconium. Smoke, tungsten, titanium, tantalum, nickel, germanium, neodymium, lanthanum Alternatively, a metal oxide containing one or more metals selected from magnesium, etc. may be used. Alternatively, silicon nitride oxide or silicon nitride may be used as the insulator 544. You can be there.

[0112] In particular, the insulator 544 may be an oxide of aluminum or hafnium, or both. Insulators including aluminum oxide, hafnium oxide, aluminum, and hafnium It is preferable to use an oxide containing hafnium (hafnium aluminate). Hafnium aluminate has higher heat resistance than hafnium oxide film. This is preferable because it is difficult to crystallize during the treatment. If b is a material that is resistant to oxidation or does not significantly decrease in conductivity even when it absorbs oxygen, it is an insulating material. The insulator 544 is not an essential component and may be appropriately designed depending on the desired transistor characteristics. stomach.

[0113] By including the insulator 544, impurities such as water and hydrogen contained in the insulator 580 are converted into acids. The oxide 530c is prevented from diffusing into the oxide 530b through the insulator 550. In addition, the excess oxygen contained in the insulator 580 can prevent the conductor 560 from being oxidized. It is possible.

[0114] The insulator 550 functions as a first gate insulating film. It is preferable that the insulator 550 is disposed in contact with the inside (top and side surfaces) of the insulating member 550. Similar to the insulator 524, an insulator containing excess oxygen and releasing oxygen when heated is used. It is preferable to form it using a

[0115] Specifically, silicon oxide having excess oxygen, silicon oxynitride, silicon nitride oxide, Silicon nitride, fluorine-doped silicon oxide, carbon-doped silicon oxide, carbon, and Silicon oxide doped with nitrogen and silicon oxide having vacancies can be used. Silicon oxide and silicon oxynitride are preferred because they are stable to heat.

[0116] An insulator that releases oxygen when heated is used as the insulator 550, and is placed on the top surface of the oxide 530c. By providing the oxide 530b in contact with the insulator 550, the oxide 530c passes through the oxide 530b. In addition, oxygen can be effectively supplied to the channel formation region of the insulator 524. In addition, it is preferable that the concentration of impurities such as water or hydrogen in the insulator 550 is reduced. The thickness of the insulator 550 is preferably 1 nm or more and 20 nm or less.

[0117] In addition, in order to efficiently supply excess oxygen contained in the insulator 550 to the oxide 530, A metal oxide may be provided between the insulating material 550 and the conductor 560. It is preferable to suppress the diffusion of oxygen from the body 550 to the conductor 560. By providing a metal oxide, the diffusion of excess oxygen from the insulator 550 to the conductor 560 is suppressed. In other words, it is possible to suppress the decrease in the amount of excess oxygen supplied to the oxide 530. In addition, oxidation of the conductor 560 due to excess oxygen can be suppressed. Any material that can be used for the insulator 544 may be used.

[0118] Note that the insulator 550 may have a stacked structure similar to the second gate insulating film. As transistors become smaller and more highly integrated, the gate insulating film becomes thinner, which reduces leakage current and other problems. Therefore, the insulator that functions as the gate insulating film is made of high-k material. By using a laminated structure of a thermally stable material and a thin film of a thin film, It is possible to reduce the gate potential during transistor operation. It may have a laminated structure.

[0119] The conductor 560 that functions as the first gate electrode is shown as a two-layer structure in FIG. However, it may have a single layer structure or a laminated structure of three or more layers.

[0120] The conductor 560a is a hydrogen atom, a hydrogen molecule, a water molecule, a nitrogen atom, a nitrogen molecule, or a nitrogen oxide molecule. (N2O, NO, NO2, etc.), conductive material with the function of suppressing the diffusion of impurities such as copper atoms It is preferable to use a material containing oxygen (for example, oxygen atoms, oxygen molecules, etc.). It is preferable to use a conductive material that has the function of suppressing the diffusion of the conductor 56. Oa has the function of suppressing oxygen diffusion, so the oxygen contained in the insulator 550 This can prevent the conductor 560b from being oxidized and the conductivity from decreasing. Examples of conductive materials that have the function of suppressing this include tantalum, tantalum nitride, and ruthenium. It is preferable to use ruthenium, ruthenium oxide, or the like as the conductor 560a. An oxide semiconductor that can be used for the oxide 530 can be used. In that case, the conductor 560 By forming the conductive layer 560b by sputtering, the electrical resistance of the conductive layer 560a is reduced, and the conductive layer 560b is This is called an OC (Oxide Conductor) electrode. can be done.

[0121] The conductor 560b is a conductive material mainly composed of tungsten, copper, or aluminum. In addition, since the conductor 560b also functions as a wiring, It is preferable to use a highly conductive material, such as tungsten, copper, or aluminum. A conductive material containing rubber as a main component can be used. For example, it may be a laminated structure of titanium or titanium nitride and the above conductive material. stomach.

[0122] The insulator 580 is provided on the conductor 542a and the conductor 542b via the insulator 544. Preferably, the insulator 580 has an excess oxygen region. For example, the insulator 58 0, silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, fluorine silicon oxide doped with carbon, silicon oxide doped with carbon and nitrogen It is preferable that the material contains silicon, silicon oxide having pores, or resin. Silicon nitride and silicon oxynitride are preferred because they are thermally stable. However, silicon oxide with vacancies can easily form excess oxygen regions in later processes. This is preferable because it allows

[0123] The insulator 580 preferably has an excess oxygen region. Oxygen is released upon heating. By providing the insulator 580 in contact with the oxide 530c, the oxygen in the insulator 580 is oxidized. The oxide 530 can be efficiently supplied through the insulator 530c. It is preferable that the concentration of impurities such as water or hydrogen in 80 is reduced.

[0124] The opening in the insulator 580 is formed to overlap the region between the conductor 542a and the conductor 542b. As a result, the conductor 560 is inserted through the opening in the insulator 580 and the conductor 542a and the conductor 542b. It is formed so as to be embedded in the region sandwiched between 542b.

[0125] In miniaturizing semiconductor devices, it is required to shorten the gate length. It is necessary to prevent the conductivity of the conductor 60 from decreasing. In this embodiment, the conductor 560 may have a shape with a high aspect ratio. The conductor 560 is provided so as to be embedded in the opening of the insulator 580. Even a shape with a high ratio can be formed without causing the conductor 560 to collapse during the process. Cut.

[0126] The insulator 574 is connected to the upper surface of the insulator 580, the upper surface of the conductor 560, and the upper surface of the insulator 550. The insulator 574 is preferably provided in contact with the , insulator 550, and insulator 580 can be provided with excess oxygen regions. Oxygen can be supplied into the oxide 530 from the excess oxygen region.

[0127] For example, the insulator 574 may be hafnium, aluminum, gallium, yttrium, Zirconium, tungsten, titanium, tantalum, nickel, germanium, or magnesium Metal oxides containing one or more metals selected from the group consisting of ammonium, cadmium, and ammonium can be used. .

[0128] In particular, aluminum oxide has a high barrier property and is a thin film of 0.5 nm to 3.0 nm. Therefore, the diffusion of hydrogen and nitrogen can be suppressed even if the sputtering method is used. The aluminum oxide film formed by this method is both an oxygen source and a barrier to impurities such as hydrogen. It can also function as a membrane.

[0129] In addition, it is preferable to provide an insulator 581 that functions as an interlayer film over the insulator 574. The insulator 581, like the insulator 524, has a low impurity concentration such as water or hydrogen. It is preferably reduced.

[0130] In addition, the openings formed in the insulators 581, 574, 580, and 544 Conductor 540a and conductor 540b are placed in the opening. 0b are provided opposite each other with the conductor 560 interposed therebetween.

[0131] The conductor 610 and the secondary battery 200 are provided on the insulator 581. , functions as wiring connecting to the conductor 540a.

[0132] The conductor 610 is preferably made of the same material as the positive electrode current collector 103. By using the same material for the positive electrode current collector 103, the positive electrode current collector 104 can be formed using the same process. This makes it possible to easily manufacture the device.

[0133] 3, compared to FIG. 2, a capacitive element 600 and a sensor element 660 are disposed on an insulator 581. They differ in the following points.

[0134] The configuration example shown in FIG. 3 has an insulator 514 on a substrate 599, and a transistor is formed on the insulator 514. 500, and an insulator 574 and an insulator 581 are provided on the transistor 500, and The conductor 540a and the insulator 574 are embedded in the insulator 580, the insulator 581, and the insulator 574. The conductor 540a is formed as a plug connecting to the conductor 542a. The conductor 540b functions as a plug that connects with the conductor 542b.

[0135] In FIG. 3, a conductor 610b is provided on an insulator 581, and the conductor 610b and the insulator An insulator 611 is provided on the edge 581, and a conductor 610b is provided on the insulator 611. A conductor 610 is provided. The conductor 610 and the conductor 610b are electrodes of the capacitor 600. The region of the insulator 611 sandwiched between the conductor 610 and the conductor 610b functions as It functions as a dielectric for the capacitive element 600 .

[0136] In addition, in FIG. 3, the secondary battery 200 and the sensor element 660 are provided on an insulator 611. can be.

[0137] The sensor element 660 includes a conductor 660a on an insulator 611 and a conductor 660c, and a layer 660b sandwiched between the conductor 660a and the conductor 660c.

[0138] The conductor 610 and the conductor 660a are made of the same material as the positive electrode current collector 103. is preferred.

[0139] The sensor element 660 may be, for example, a pressure sensor, a piezoelectric sensor, an acceleration sensor, a gyro sensor, or the like. Sensors, magnetic sensors, optical sensors, infrared sensors, distance sensors, pulse sensors, ultrasonic sensors , a touch sensor, a fingerprint sensor, etc. can be used.

[0140] An example in which a piezoelectric sensor is used as the sensor element 660 is shown below. This allows pressure, displacement, etc. to be detected.

[0141] It is preferable to use a titanium compound as the conductor 660a. Titanium is preferably used. Alternatively, titanium nitride is preferably used. The use of the conductor 660a may increase the crystallinity of the layer 660b. For example, a second conductive layer may be formed on the titanium substrate. The use of titanium and platinum on titanium in a stacked manner can improve the crystallinity of layer 660b. Sexuality may increase.

[0142] The layer 660b is made of a piezoelectric ceramic such as lead zirconate titanate or barium titanate. Lead zirconate titanate can be used. x Ti 1-x )O3 Barium titanate is sometimes expressed as BaTiO3.

[0143] A compound containing strontium (e.g., For example, La 0.5 Sr 0.5 CoO3, SrTiO3, SrRuO3, etc.), lanthanum The compounds (LaNiO3) and (Bi,La)4Ti3O 12 etc.), containing yttrium Compounds such as Y1Ba2Cu3O 7-x etc.), etc., by laminating one or more selected from It may be provided.

[0144] As shown in the configuration example of FIG. 4, an OS transistor is formed in the region sandwiched between the insulator 514 and the insulator 574. A transistor 500 and a secondary battery 200 may be provided.

[0145] The transistor 500 shown in FIG. 4 has a bottom-contact structure. 4, a conductor 542a and a conductor 542b are provided on an insulator 524. The transistor 500 includes an oxide layer on the insulator 524, the conductor 542a, and the conductor 542b. 530, an insulator 550 on the oxide 530, and a conductor 560 on the insulator 550. In addition, in FIG. 4, the conductor 560 and the conductor 503 are overlapped with each other with the oxide 530 sandwiched therebetween. Between the conductor 503 and the oxide 530, an insulator 520, an insulator 522, and an insulator 523 are provided. and an insulator 524 is provided.

[0146] 4, the secondary battery 200 is provided on an insulator 524. Protection of the secondary battery 200 An insulating layer 550 is provided on the layer 206, and an insulator 580 is provided on the insulating layer 550; An insulator 574 is provided on the insulator 580 .

[0147] Conductor 542a and conductor 542b are connected to the source and drain electrodes of transistor 500. The conductor 542a and the conductor 542b function as the positive electrode current collector 10. It is preferable to use the same material as in 3.

[0148] 4 and FIG. 5 described later, the transistor 500 is the transistor shown in FIG. 2 etc. A transistor structure may also be used.

[0149] As shown in the configuration example of FIG. 5, the secondary battery 200 is provided on a substrate 599. An insulator 580b is provided on the insulator 580b, an insulator 514 is provided on the insulator 514, and a The insulator 580b may be made of an insulating material. Reference can be made to the field 580.

[0150] As shown in FIG. 6, the substrate 599 may be silicon, silicon germanium, or silicon. The transistor 300 is provided on the substrate 599 using silicon carbide. Even if an insulator 514, a transistor 500, a capacitor element 600, a sensor element 660, etc. are provided, Some of the transistors included in the battery control circuit of one embodiment of the present invention may be replaced with transistors, for example. It may be configured using a controller 300.

[0151] The transistor 300 shown in FIG. 6 is provided on a substrate 599 and includes a conductor 316, an insulator 317, and a 15, a semiconductor region 313 consisting of a part of the substrate 599, a low resistance region 314a, and a low resistance One of the low resistance region 314a and the low resistance region 314b is a source region. one functions as a source region and the other as a drain region.

[0152] The transistor 300 has a semiconductor region 313 whose upper surface and side surfaces in the channel width direction are insulators. The transistor 300 is covered with a conductor 316 via a fin 315. By using this type, the effective channel width increases, and the on-state characteristics can be improved. In addition, the contribution of the electric field of the gate electrode can be increased, so that the on-state of the transistor 300 The characteristics can be improved.

[0153] The transistor 300 may be a p-channel transistor or an n-channel transistor. The transistor may be either one of the two.

[0154] The low resistance region 314a and the low resistance region 314b are formed by the semiconductor layer applied to the semiconductor region 313. In addition to the conductive material, elements that impart n-type conductivity, such as arsenic and phosphorus, or p-type conductivity, such as boron, are added. It contains elements that impart electrical conductivity to the material.

[0155] The conductor 316, which functions as a gate electrode, is made of arsenic, phosphorus, or the like, which provides n-type conductivity. Semiconductor materials such as silicon that contain elements or elements that give them p-type conductivity, such as boron Conductive materials such as aluminum, metal, alloy, or metal oxide materials can be used. .

[0156] Since the work function is determined by the material of the conductor, it is necessary to select the material of the conductor. Specifically, the conductor is made of nitride silicon, and the threshold voltage of the transistor can be adjusted. It is preferable to use materials such as tantalum or tantalum nitride. To achieve this, metal materials such as tungsten and aluminum are used as layers for the conductor. It is preferable to use tungsten, in particular, in terms of heat resistance.

[0157] The transistor 300 is formed on a silicon on insulator (SOI) substrate. It may be formed using, for example.

[0158] In addition, for the SOI substrate, oxygen ions are implanted into a mirror-polished wafer, and then the wafer is heated to a high temperature. This allows an oxide layer to form at a certain depth from the surface, and also removes defects that have occurred in the surface layer. SIMOX (Separation by Implanted Oxygen) substrate and growth of microvoids formed by hydrogen ion implantation by heat treatment Smart Cut method, ELTRAN method (registered trademark: Epi SOI substrates formed by using techniques such as tactile layer transfer (TTL) are used. A transistor formed using a single crystal substrate may have a single crystal in the channel formation region. It has a semiconductor.

[0159] Over the transistor 300 are insulators 320, 322, 324, and The edge members 326 are stacked in order.

[0160] The insulators 320, 322, 324, and 326 may be, for example, an acid. silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, aluminum oxide, Aluminum oxynitride, aluminum nitride oxide, aluminum nitride, or the like may be used.

[0161] In this specification, silicon oxynitride refers to a material having a higher content of oxygen than nitrogen in its composition. Silicon nitride oxide refers to a material that contains more nitrogen than oxygen. In this specification, aluminum oxynitride refers to a material with a high content. Aluminum oxide nitride is a material that has a higher oxygen content than nitrogen. It refers to a material that contains more nitrogen than oxygen as a constituent.

[0162] The insulator 322 serves to eliminate a step caused by the transistor 300 and other components disposed below it. For example, the top surface of the insulator 322 may have a function as a planarizing film. To improve flatness, the surface is flattened by a planarization process using chemical mechanical polishing (CMP) or other methods. It may be possible.

[0163] The insulator 324 also includes a substrate 599 or a transistor 300, etc. A film having a barrier property to prevent diffusion of hydrogen and impurities is formed in the area where the star 500 is provided. It is preferable to use

[0164] An example of a film having a barrier property against hydrogen is silicon nitride formed by CVD. Here, a semiconductor having an oxide semiconductor such as the transistor 500 can be used. The diffusion of hydrogen into semiconductor elements can cause a deterioration in the characteristics of the semiconductor elements. Therefore, a film that suppresses hydrogen diffusion is provided between the transistor 500 and the transistor 300. Specifically, the film that suppresses the diffusion of hydrogen is a film that reduces the amount of hydrogen desorption. The membrane is thin.

[0165] The amount of hydrogen desorption can be analyzed using, for example, thermal desorption spectroscopy (TDS). For example, the amount of hydrogen desorbed from the insulator 324 can be determined by TDS analysis as follows: In the range of 50°C to 500°C, the amount of desorption converted to hydrogen atoms is Converted to a hit, it's 10 x 10 15 atoms / cm 2 Less than or equal to 5 x 10 15 a toms / cm 2 The following is fine.

[0166] It is preferable that the insulator 326 has a lower dielectric constant than the insulator 324. For example, The dielectric constant of the insulator 326 is preferably less than 4, more preferably less than 3. The relative dielectric constant of the insulator 326 is preferably 0.7 times or less than the relative dielectric constant of the insulator 324, and more preferably 0.6 times or less. By using a material with a low dielectric constant as the interlayer film, the parasitic capacitance generated between wirings can be reduced. It can be reduced.

[0167] In addition, the insulators 320, 322, 324, and 326 are provided with conductors 3 28, and conductor 330 are embedded. 30 has a function as a plug or wiring. In the case of a conductor having a plurality of components, the same reference numeral may be used to denote the same components. In the fine print, the wiring and the plug connected to the wiring may be integrated. When part of the conductor functions as a wiring, and when part of the conductor functions as a plug, There are also cases where this is the case.

[0168] The materials for each plug and wiring (conductor 328, conductor 330, etc.) include metal materials, alloys, and the like. Conductive materials such as gold, metal nitride, or metal oxide materials are used as single or multilayered layers. High-melting materials such as tungsten and molybdenum, which have both heat resistance and electrical conductivity, can be used. It is preferable to use a point material, and it is preferable to use tungsten. It is preferable to form the wiring layer from a low-resistance conductive material such as aluminum or copper. This can reduce the wiring resistance.

[0169] For example, the insulator 350 has a barrier property against hydrogen, similar to the insulator 324. It is preferable to use an insulator having a barrier property against hydrogen. In particular, it is preferable that the insulating material has a barrier property against hydrogen. It is preferable that a conductor having a barrier property against hydrogen is formed at the opening. As a result, the transistor 300 and the transistor 500 can be separated by the barrier layer. Therefore, the diffusion of hydrogen from the transistor 300 to the transistor 500 can be suppressed. .

[0170] As a conductor having a barrier property against hydrogen, for example, tantalum nitride or the like is used. In addition, by laminating tantalum nitride and highly conductive tungsten, The diffusion of hydrogen from the transistor 300 can be suppressed while maintaining the overall conductivity. In this case, the tantalum nitride layer having a barrier property against hydrogen is It is preferable that the insulating material 350 has a structure in which the insulating material 350 is in contact with the insulating material 350.

[0171] An insulator 512 is provided on the insulator 350, and an insulator 514 is provided on the insulator 512. The materials that can be used for the insulator 512 are, for example, You can refer to it.

[0172] The transistor 500 shown in FIG. 7A is a modification of the transistor 500 shown in FIG. 7A is a cross-sectional view of a transistor 500 in the channel length direction, and FIG. 7B is a cross-sectional view of the transistor 500 in the channel length direction shown in FIG. 7A. 1 is a cross-sectional view of a transistor 500 in the channel width direction.

[0173] The transistor 500 shown in FIG. 7A is different from the transistor 500 shown in FIG. 2A in that it does not have oxide 530c. The structure of the transistor 500 is different from that of the transistor 500. An insulator 550 is disposed on the bottom and side surfaces of the opening formed between the insulator 550 and the insulating material 550. A conductor 560 is disposed on the surface of the transistor 50. 00 does not have the oxide 530c, and therefore, the oxide 530c and the The parasitic capacitance between the conductor 560 can be eliminated.

[0174] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0175] (Embodiment 3) To increase the output voltage of a thin-film secondary battery, the secondary batteries can be connected in series. In the second embodiment, an example of a secondary battery having one cell was shown, but in this embodiment, a secondary battery having multiple cells is shown. This section describes an example of fabricating a thin-film secondary battery in which multiple cells are connected in series.

[0176] FIG. 8A shows a top view of the first secondary battery immediately after it is formed, and FIG. 8B shows a top view of the first secondary battery immediately after it is formed. 8A and 8B show top views of the second embodiment. The same parts as in FIG. 5A are designated by the same reference numerals.

[0177] 8A shows the state immediately after the deposition of the negative electrode current collector 205. The negative electrode current collector 205 shown in FIG. 8A has a top surface shape on the solid electrolyte layer side. It is in contact with a portion of the surface and also with the insulating surface of the substrate.

[0178] Then, as shown in FIG. 8B, the first negative electrode current collector 205 that does not overlap with the first negative electrode active material layer is A second negative electrode active material layer is formed on the region. Then, a second solid electrolyte layer 213 is formed. A second positive electrode active material layer and a second positive electrode current collector 215 are formed thereon. Finally, a protective layer 20 Form 6.

[0179] FIG. 8B shows a configuration in which two solid-state secondary batteries are arranged on a plane and connected in series.

[0180] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0181] (Fourth embodiment) In this embodiment, an example of a power storage device of one embodiment of the present invention will be described.

[0182] <Example of an electricity storage device 1> 9 shows an example of a power storage device 90. The power storage device 90 shown in FIG. The battery control circuit 91 includes a circuit using the above-mentioned OS transistor. Preferably, a path is installed.

[0183] The battery control circuit 91 includes a circuit 91a and a circuit 91b.

[0184] The circuit 91a includes a cell balance circuit 130, a detection circuit 185, a detection circuit 186, and a detection circuit It has an MSD, a detection circuit SD, a temperature sensor TS, and a logic circuit 182.

[0185] The circuit 91b also includes a transistor 140 and a transistor 150. Various transistors can be used as resistor 140 and transistor 150. As shown in FIG. 9, the transistor 140 and the transistor 150 are It is preferable to have a raw diode.

[0186] The circuit 91a includes a cell balance circuit 130, a detection circuit 185, a detection circuit 186, and a detection The transistors included in the circuit MSD, the detection circuit SD, the temperature sensor TS, and the logic circuit 182 An OS transistor can be used as the gate electrode.

[0187] The transistors 140 and 150 included in the circuit 91b are, for example, single-ended transistors. Consider an example in which a transistor having a crystalline silicon channel region is used. In this case, for example, the transistor 140 and the transistor 150 are formed on a silicon substrate. , an OS transistor can be formed thereon using a deposition process, and the circuit 91a and circuit 91b can be formed on the same substrate. This can reduce costs, for example. Furthermore, circuit integration becomes possible, and the circuit area can be reduced. In addition, by providing the circuit 91a and the circuit 91b stacked on the same substrate, the wiring The wiring resistance can be reduced. A large current may flow through the wiring, so it is preferable to reduce the wiring resistance.

[0188] The battery pack 120 has a plurality of battery cells 121. In FIG. 9, the battery pack 120 has n battery cells 121. The k-th battery cell (k is an integer between 1 and n) is represented as battery cell 121(k). The battery pack 120 has a plurality of battery cells that are electrically connected in series. FIG. 9 shows an example in which a battery pack 120 has a plurality of battery cells 121 connected in series. However, the battery pack 120 may have only one battery. Alternatively, the battery pack 120 may have multiple batteries. The battery may include a plurality of batteries connected in parallel.

[0189] Here, as the battery cell, for example, a secondary battery shown in the embodiment described later can be used. For example, a secondary battery having a wound battery element can be used. It is preferable that the battery has an exterior body. For example, a cylindrical exterior body or a square exterior body may be used. The outer casing material can be a metal plate covered with an insulator or a metal sandwiched between insulators. A battery cell may be made of a material such as a film. For example, the battery cell has a pair of positive and negative electrodes. The battery cell has a terminal electrically connected to the positive electrode and a terminal electrically connected to the negative electrode. In addition, when a battery cell has a part of the configuration of a battery control circuit according to one embodiment of the present invention, There is.

[0190] The cell balance circuit 130 controls the charging of each battery cell 121 in the battery pack 120. The detection circuit 185 has a function of detecting overcharging and overdischarging of the battery pack 120. The detection circuit 186 has a function of detecting an overcurrent of discharge and an overcurrent of charge of the battery pack 120. It has.

[0191] The detection circuit MSD has the function of detecting micro-short circuits.

[0192] A micro-short refers to a tiny short circuit inside a secondary battery. It is not so severe that the positive and negative electrodes are short-circuited and charging and discharging becomes impossible, but rather a small short circuit occurs. This refers to the phenomenon in which a short-circuit current flows for a short period of time. By repeating this process several times, metallic elements such as lithium and cobalt are precipitated inside the battery. As the deposits grow, local current concentration occurs in parts of the positive and negative electrodes, causing the separator This may cause parts of the reactor to stop functioning or side reactions to occur. It is estimated that

[0193] The detection circuit SD detects, for example, a short circuit in a circuit operated using the battery pack 120. The detection circuit SD detects, for example, the charging current and discharging current of the battery pack 120.

[0194] The battery control circuit 91 controls the positive electrodes of the n battery cells 121 in the battery pack 120. The terminals VC1 to VCN are electrically connected to the negative electrode of the n-th battery cell 121. and a terminal VSSS connected to

[0195] The logic circuit 182 includes a detection circuit 185, a detection circuit 186, a detection circuit SD, and a detection circuit MSD. and the transistor 140 and the transistor The logic circuit 182 has a function of controlling the external circuit of the battery control circuit 91. Alternatively, a signal may be sent to a charging circuit provided inside the device. In this case, for example, the logic circuit 1 Charging of the secondary battery is controlled in response to a signal given to the charging circuit from 82. For example, the electrical circuit has a function of controlling the conditions for charging the battery. A signal for controlling the above-mentioned conditions is transmitted to another circuit, for example, a cell balance circuit or an overcharge circuit according to one embodiment of the present invention. The detection circuit, transistor 140, transistor 150, transistor 140 and transistor The resistor 150 is provided to a circuit for controlling the resistor 150, etc.

[0196] The transistor 140 and the transistor 150 control charging or discharging of the battery pack 120. In one example, the transistor 140 has a function of controlling the The control signal T1 controls the conductive state or non-conductive state, and charges the battery pack 120. The transistor 150 is controlled by a control signal T2 provided by the logic circuit 182. The conductive state or non-conductive state is controlled by the In the example shown in FIG. 9, one of the source and drain of the transistor 140 is , electrically connected to the terminal VSSS. The other end is electrically connected to one of the source and drain of the transistor 150. The other of the source and drain of the resistor 150 is electrically connected to the terminal VM. For example, M is electrically connected to the negative pole of the charger. Also, the terminal VM is, for example, a discharge The load is electrically connected to the

[0197] The battery control circuit 91 controls the voltage values ​​(monitor voltages) of the terminals of the battery cells 121 of the battery pack 120. The battery may have the function of observing the voltage, and the current value (monitor current) flowing through the battery pack. For example, the on-current of the transistor 140 or the transistor 150 is observed as the monitor current. Alternatively, a resistor element may be provided in series with the transistor 140 or the like, and the resistor The current value of the element may be observed.

[0198] The temperature sensor TS measures the temperature of the battery cell 121 and determines the temperature of the battery cell 121 based on the measured temperature. For example, at low temperatures, the secondary battery may have a function of controlling the charging and discharging of the secondary battery. Resistance may increase, which may reduce charge and discharge current densities. In addition, the resistance of the secondary battery may decrease at high temperatures, so the discharge current density In addition, by increasing the charging current at high temperatures, the secondary battery If there is a concern about deterioration of the characteristics, the charging current may be controlled to a value that suppresses the deterioration, for example. Data such as charging conditions and discharging conditions is stored in the memory circuit of the battery control circuit 91 of one embodiment of the present invention. It is preferable that the battery control circuit 91 or the assembled battery 1 is stored in the battery pack 1 by charging. In such cases, adjust the charging temperature according to the measured temperature. For example, the charging current may be reduced as the temperature rises.

[0199] Cell balance circuit 130, detection circuit 185, detection circuit 186, detection circuit MSD, detection circuit The SD and the temperature sensor TS preferably have a memory element. Maintains the battery's upper and lower limit voltages, voltages corresponding to overcurrent, and voltages corresponding to temperature. It is possible.

[0200] The memory element may have the configuration of the memory element 114 shown in FIG. 10A. The memory element 114 shown in FIG.

[0201] The transistor 162 is preferably an OS transistor. In this configuration, the memory element 114 includes an OS transistor. The leakage current (hereinafter referred to as "off current") that flows between the source and drain when the device is turned off is extremely low. This allows a desired voltage to be held in the memory element.

[0202] FIG. 10B illustrates a memory element 114 in which the transistor 162 has a second gate. Unlike Figure 10A, the second gate is called a back gate or bottom gate. The second gate of the OS transistor will be described in detail in a later embodiment. .

[0203] Next, the components of the cell balancing circuit 130 and the detection circuit 185 will be described.

[0204] FIG. 11 shows a cell balance circuit 130a and a detection circuit 121 corresponding to one battery cell 121. Shows 85a.

[0205] The cell balance circuit 130 shown in FIG. 9 has a plurality of cell balance circuits 130a. A cell balance circuit 130a is connected to each battery cell. In the configuration where the battery cells are connected in a row, cell balancing is performed for each of the battery cells 121. By providing a circuit 130a and a transistor 132 and connecting the transistor 132 in series, As a result, when charging the plurality of battery cells 121 connected in series, This can reduce the variation in charging voltage between the batteries.

[0206] The detection circuit 185a shown in FIG. 11 includes a circuit 185c and a circuit 185d. The detection circuit 85c has a function of detecting overcharging, and the detection circuit 185d has a function of detecting overdischarging. do.

[0207] The detection circuit 185 shown in FIG. 9 has a plurality of detection circuits 185a, one for each battery cell. Alternatively, the detection circuit 185a shown in FIG. 21 connected in series, one detection circuit 185a may be provided.

[0208] In FIG. 11, a transistor 132 and a resistor element 131 are connected in series. One of the source and drain of the resistor 132 is connected to the negative electrode of the battery cell 121, and the other is connected to the resistor element The other electrode of the resistor element is electrically connected to the positive electrode of the secondary battery. is electrically connected to

[0209] Here, one of the source and drain of the transistor 132 is connected to the positive electrode of the battery cell 121. , the other electrode of the resistor element 131 is connected to one electrode of the battery cell 121 The negative electrodes of the first and second electrodes may be electrically connected to the negative electrodes of the second and third electrodes, respectively.

[0210] In addition, in FIG. 11, the cell balance circuit 130a, the circuit 185c, and the circuit 185d Each of the comparators 113 and the storage element 114 has a capacitance The cell balance circuit 130a includes an element 161 and a transistor 162. The non-inverting input terminal or the inverting input terminal of each comparator 113 of the circuit 185c and the circuit 185d One of the input terminals is electrically connected to the storage element 114. , one of the source and drain of the transistor 162 included in each memory element 114 A common terminal, here a terminal VT, is electrically connected to the storage element 114. The gate of the transistor 162 included in each memory element 114 is connected to a terminal (cell balance). In the sense circuit a130, the terminal SH6, in the circuit 185c, the terminal SH1, in the circuit 18 In 5d, the terminal SH2) is electrically connected.

[0211] In FIG. 11, the cell balance circuit 130a electrically connects the positive and negative electrodes of the battery cell 121. The positive electrode of the battery cell 121 is electrically connected to the terminal VC1, and the negative electrode is connected to the terminal V In the cell balance circuit 130a, the storage element 114 has The other of the source and drain of the transistor 162 is connected to the inverting input of the comparator 113. In the cell balance circuit 130a, the comparator 11 Preferably, the non-inverting input terminal of 3 is electrically connected to the terminal VC1. As shown in FIG. 1, the non-inverting input terminal of the comparator 113 has a connection between the terminal VC1 and the terminal VC2. A voltage divided by resistors may be applied. A node connected to the other of the source and drain of the transistor 162 included in the 114 is Let's call this node N6.

[0212] In FIG. 11, the detection circuit 185a is electrically connected to the positive and negative terminals of the battery cell 121. In the circuit 185c, the other of the source and drain of the transistor 162 is connected to a The inverting input terminal of the comparator is electrically connected. The non-inverting input terminal of the regulator 113 is preferably electrically connected to the terminal VC1. 11, the non-inverting input terminal of the comparator 113 is connected to the terminal VC1 and the terminal V A voltage divided by resistors may be applied between C2. The node connected to the other of the source and drain of the capacitor 162 is referred to as a node N1.

[0213] In the circuit 185d, the other of the source and drain of the transistor 162 is connected to a comparator. The non-inverting input terminal of the comparator is electrically connected to the circuit 185d. The inverting input terminal of the inverter 113 is preferably electrically connected to the terminal VC1. As shown in 11, the inverting input terminal of the comparator 113 is connected between the terminal VC1 and the terminal VC2. In the circuit 185d, a voltage obtained by dividing the voltage by a resistor may be applied. The node connected to the other of the source and drain is defined as node N2.

[0214] In the cell balance circuit 130a and the detection circuit 185a, The node to which the other electrode of the capacitance element 161 is connected (here, the node N6, the node N1, and and node N2) are held in an off state by turning transistor 162 off.

[0215] The terminal VT is connected to the cell balance circuit 130a, the circuit 185c, and the circuit 185d in this order. Analog signals are applied to the nodes N6, N1 and N2 in sequence. The first node among the nodes N6, N1, and N2 is After applying the analog signal, the transistor 162 connected to the node is turned off. The potential of the first node is then maintained. Then, a potential is applied to the second node and maintained. Then, the potential of the third node is applied and maintained. The control is performed by signals applied to terminals SH1, SH2 and SH6.

[0216] The cell balance circuit 130a and the detection circuit 185a shown in FIG. By providing each of the battery cells 121 with a corresponding one of the plurality of battery cells 121, In each case, the voltage difference between both ends (the difference between the positive and negative poles) can be controlled individually. Furthermore, the cell balance circuit 130a can set the first upper limit of the positive electrode for each battery cell 121. A preferred value for the voltage can be stored in the storage element 114 .

[0217] The cell balance circuit 130a is configured to balance the voltage of the positive electrode of the battery cell 121 with the voltage of the comparator 113. Depending on the voltage at the non-inverting input terminal and the By controlling the transistor 132, By adjusting the ratio between the amount of current flowing through the resistance element 131 and the amount of current flowing through the battery cell 121, For example, when charging of the battery cell 121 is stopped, a current is applied to the resistance element 131. to limit the current flowing through the battery cell 121.

[0218] In FIG. 9, a plurality of battery cells 121 are electrically connected in series between terminals VC1 and VSSS. By passing a current between the terminal VC1 and the terminal VSSS, multiple The battery cell 121 is charged.

[0219] The positive electrode of one of the plurality of battery cells 121 reaches a predetermined voltage, Consider the case where the current is limited. In this case, the transistor connected in parallel to the battery cell By passing a current through the transistor 132 and the resistor element 131, the terminal VC1 and the terminal VS The current path between the SS and the positive electrode is not interrupted and the positive electrode does not reach the specified voltage. In other words, the charging of the battery cell 121 that has been completely charged can be continued. In 21, the charging is stopped by turning on the transistor 132. In the battery cells 121 where charging is not completed, the transistor 132 is turned off to stop charging. Continue.

[0220] If there is a variation in resistance for each battery cell 121, a battery cell 121 with low resistance may The charging of a battery cell 121 having a higher resistance than another battery cell 121 is completed first, and the charging of a battery cell 121 having a higher resistance than another battery cell 121 is completed first. Here, insufficient charging may occur when, for example, the voltage difference between the positive electrode and the negative electrode is not as desired. By using the cell balance circuit 130, the voltage during charging The voltage of the positive electrode of each battery cell 121 is controlled based on the voltage of the negative electrode of each battery cell. This can be done.

[0221] In the cell balance circuit according to one embodiment of the present invention, a circuit provided outside the battery control circuit 91 Without using a calculation circuit such as an MPU or MCU, can control the charging voltage or charging capacity of multiple battery cells.

[0222] That is, by using N cell balance circuits 130a, the plurality of battery cells 12 1 after charging, for example, when fully charged, can be reduced. In some cases, the overall capacity of the battery 120 may be increased. Therefore, the number of charge / discharge cycles of the battery pack 121 can be reduced. 0 durability may be increased.

[0223] The circuit 185c is connected to the second upper terminal of the positive electrode of each battery cell 121 for charging the battery cell 121. The second upper limit voltage can be stored in the storage element 114. The circuit 185d stores the lower limit voltage of the positive electrode in the discharge in the memory element 114. The lower limit voltage is sometimes called an overdischarge voltage.

[0224] The comparator that constitutes the detection circuit 185 changes its output from L level to H level. The threshold is different when the signal changes from H level to L level and when the signal changes from H level to L level. The reference potential input of the hysteresis comparator is connected to the reference potential input of the hysteresis comparator. The storage element preferably has a function of holding two threshold values.

[0225] In the detection circuit 185, a circuit provided outside the battery control circuit 91, such as an MPU, It is possible to calculate the temperature of a single battery cell or multiple battery cells without using an arithmetic circuit such as an MCU. It can detect overcharging and over-discharging and protect the battery cells. When a drop is detected, the control circuit of one embodiment of the present invention cuts off the discharge current to prevent the voltage drop. If the discharge current is not blocked sufficiently, leakage current may occur, causing a drop in voltage. There are cases where leakage current can be suppressed by using a circuit configuration that uses power gating. Furthermore, a circuit configuration using OS transistors can sometimes suppress leakage current. be.

[0226] The battery cell includes a cell balance circuit connected to the battery cell, a circuit for detecting overcharge, and The upper limit voltage detected by the cell balance circuit is, for example, For example, the voltage is lower than the upper limit detected by the overcharge detection circuit. In the first step, the cell balance circuit detects when the battery cell reaches its upper limit voltage and starts charging. Change the conditions. For example, lower the current density of the charge. Or, start discharging. After that, as the charging voltage of the battery cell increases, the circuit that detects overcharge detects If the upper limit voltage is detected, the charging conditions of the battery cells are changed in the second step. Here, for example, charging is stopped and discharging is started.

[0227] <Further Components of the Power Storage Device> An example of further components included in the power storage device of one embodiment of the present invention will be described below.

[0228] The battery control circuit 91 also has a terminal group AH. The terminal group AH may include one or more terminals. It has a terminal.

[0229] As shown in FIG. 12, the terminal group AH is connected to the logic circuit 182. and a function of transmitting a signal from the logic circuit 182 to the battery control circuit 91. It is preferable that the power supply circuit has a function to provide the power supply circuit with an external circuit.

[0230] FIG. 12A shows an example of the logic circuit 182. The logic circuit 182 shown in FIG. interface circuit IF, counter circuit CND, latch circuit LTC and transistor 17 2. An OS transistor is preferably used as the transistor 172. The structure shown in FIG. 12A includes only an OS transistor included in a battery control circuit of one embodiment of the present invention. 12A , or only a part of the configuration shown in FIG. 12A may be a battery control circuit of one embodiment of the present invention. 12A. Only a part of the configuration shown in FIG. 12A may be configured with an OS transistor. In the case where the battery control circuit according to one embodiment of the present invention is configured using an OS transistor, A part of the transistor is made of, for example, single crystal silicon.

[0231] The interface circuit IF includes an output terminal OUT11 of the detection circuit 185 and an output terminal The signal from OUT12, the output terminal OUT31 and the output terminal OUT32 of the detection circuit 186 and a signal from the output terminal OUT41 of the detection circuit SD. The output terminal OUT11 provides a signal corresponding to, for example, overcharging. The output terminal OUT12 provides a signal corresponding to, for example, The output terminal OUT31 outputs a signal corresponding to an overcurrent during charging, for example. The output terminal OUT32 outputs a signal corresponding to an overcurrent during discharge, for example. .

[0232] The interface circuit IF outputs signals to detect abnormalities, such as overcharge, overdischarge, and overvoltage. When detecting a signal corresponding to at least one of the currents, a signal PG is applied to the transistor 17. Give to gate 2.

[0233] The transistor 172 is connected to the counter circuit CND.

[0234] The counter circuit CND receives the signal PG as a signal that turns on the transistor 172, more specifically Specifically, when a high potential signal is output, a counter and a delay circuit are operated. On the other hand, the signal PG is a signal that turns off the transistor 172, more specifically, for example, a low When outputting a potential signal, the operation of the counter circuit CND is stopped or The counter circuit CN can be set to standby mode. A signal res is given to D and the latch circuit LTC. The signal res is a reset signal. The counter circuit CND is given the signal res and starts counting. The signal en is enabled. The counter circuit CND starts or stops operation by the signal en. do.

[0235] When a signal to detect an abnormality is given to the interface circuit IF, the counter circuit After counting for a certain period of time in the CND, a signal corresponding to the detected abnormality is output to the counter circuit. The signal is given to the latch circuit LTC via CND.

[0236] The latch circuit LTC switches transistor 140 or transistor 15 depending on the detected abnormality. A signal that turns the transistor off is applied to the gate of 0.

[0237] FIG. 13A shows an example of a circuit diagram of the detection circuit 186. The detection circuit 186 has two comparators. It has data 113.

[0238] The non-inverting input terminal of one comparator 113 holds a voltage corresponding to the discharge overcurrent detection. The memory element 114 is electrically connected to the gate of the transistor included in the memory element 114. The terminal SH3 is electrically connected to the output terminal. The terminal SENS is electrically connected to the inverting input terminal. When an overcurrent is detected by the voltage applied to the inverting input terminal, the output terminal O The output from the UT32 is inverted.

[0239] The other comparator 113 has a non-inverting input terminal electrically connected to the terminal SENS. The inverting input terminal is connected to a storage element 114 that stores a voltage corresponding to the charging overcurrent detection. The gate of the transistor in the memory element 114 is electrically connected to the terminal SH4. When an overcurrent is detected by the voltage applied to the non-inverting input terminal, the output terminal The output from OUT31 is inverted.

[0240] The temperature sensor TS detects the temperature of the battery pack 120 or the power storage device 90 including the battery pack 120. FIG. 13B is a circuit diagram showing an example of a temperature sensor TS. The circuit diagram shown in 13B may represent a portion of the circuit of the temperature sensor TS.

[0241] In FIG. 13B, the temperature sensor TS has three comparators 113. The inverting input terminal of the parameter is connected to a voltage VT (VT=Tm1, Tm2, ​​T m3) are given. Each given voltage VT is electrically connected to the inverting input terminal. The voltages Tm1, Tm2, ​​and Tm3 are stored in a memory element 114 connected to the It may be provided from the pond control circuit 91.

[0242] The input terminal Vt is supplied with a voltage corresponding to the measured temperature. The signals are given to the non-inverting input terminals of the comparators 113 .

[0243] The voltage applied to the input terminal Vt and the voltage of the inverting input terminal of each comparator 113 The output terminals of each comparator (output terminal OUT51, output A signal is output from the terminal OUT52 and the output terminal OUT53, allowing the temperature to be determined. do.

[0244] OS transistors have the property that their resistance decreases as the temperature rises. This voltage can be applied to the input terminal Vt, for example. That's fine.

[0245] The logic circuit 182 detects the output of the temperature sensor TS and determines the temperature range in which the battery pack 120 can operate. If the range is exceeded, transistor 140 and / or transistor 150 are made non-conductive. Alternatively, charging and / or discharging may be stopped.

[0246] <Battery cell> The battery cell 121 can be the secondary battery 200 shown in the previous embodiment.

[0247] <Transistor> In one embodiment of the present invention, a memory element including an OS transistor is used. This means that the leakage current that flows between the source and drain when the device is off (hereinafter referred to as the off current) is extremely low. By utilizing this, the reference voltage can be held in the memory element. Since the power supply can be turned off, a memory element having an OS transistor can be used. This allows the reference voltage to be maintained with extremely low power consumption.

[0248] In addition, a memory element including an OS transistor can hold an analog potential. For example, the voltage of a secondary battery is converted into a digital value using an analog-to-digital conversion circuit. This eliminates the need for a conversion circuit, reducing the circuit area. It is possible.

[0249] In addition, in a memory element using an OS transistor, the charge can be charged or discharged. The reference voltage can be rewritten and read, allowing for virtually unlimited monitoring of the voltage. The memory element using OS transistors is suitable for magnetic memory and Unlike resistive memory, it does not involve structural changes at the atomic level, so it can be easily rewritten. In addition, memory elements using OS transistors have excellent durability. Even after repeated rewrite operations, no instability due to an increase in electron trap centers is observed.

[0250] In addition, OS transistors have extremely low off-state current and can switch even in high-temperature environments. Therefore, the battery pack 120 has good characteristics even in a high-temperature environment. Charging or discharging can be controlled without malfunction.

[0251] In addition, memory elements using OS transistors can be stacked on circuits using Si transistors. By layering, it can be freely arranged, making integration easy. Transistors can be manufactured using the same manufacturing equipment as Si transistors. Therefore, it can be produced at low cost.

[0252] In addition to the gate electrode, source electrode, and drain electrode, the OS transistor also has a buffer If a back gate electrode is included, it can be a four-terminal semiconductor element. The input and output of signals flowing between the source and drain are controlled independently according to the voltage applied to the gate electrode. Therefore, it is possible to design circuits using the same concept as LSI. In addition, OS transistors can perform the same functions as Si transistors in high-temperature environments. Specifically, the temperature is 100°C or higher and 200°C or lower, preferably The ratio of on-current to off-current is large even at high temperatures of 125°C to 150°C. Therefore, a good switching operation can be performed.

[0253] It is preferable to use an OS transistor as the transistor 162. The transistor 132 may be an OS transistor.

[0254] The comparator may also be configured using an OS transistor.

[0255] This embodiment mode can be combined with the descriptions of other embodiment modes as appropriate.

[0256] (Embodiment 5) In this embodiment, an example of a detection circuit included in a battery control circuit of one embodiment of the present invention will be described. The semiconductor device according to one embodiment of the present invention is a secondary battery that is being charged and discharged. The potential between the positive and negative electrodes is sampled (acquired) at predetermined intervals, and the sampled potential By comparing the potential between the positive and negative electrodes after sampling with the potential between the positive and negative electrodes, it is possible to detect the instantaneous It has the function of detecting the potential fluctuation (here, the potential drop) at predetermined intervals. By repeating the charging and discharging, it is possible to cope with the potential fluctuation of the secondary battery during charging and discharging. The semiconductor device can be operated using the potential between the positive and negative electrodes of the secondary battery.

[0257] In this embodiment, when the secondary battery is being charged, the voltage of the secondary battery and the semiconductor device is The potential fluctuation during discharge will be explained using timing charts etc. Since it can be easily understood by anyone skilled in the art, the explanation will be omitted.

[0258] <An example of a detection circuit> FIG. 14A is a circuit diagram showing a configuration example of the detection circuit MSD. The transistors C11 to C15, the capacitor C11, and the comparator 50 are included. In the drawings described in this specification, the flow of main signals is indicated by arrows or lines. The comparator 50 of the detection circuit MSD may be A hysteresis comparator may be used. The detection circuit MSD is made up of a plurality of circuits connected in series. The detection may be performed for all battery cells in a group, or may be performed for each battery cell. stomach.

[0259] In addition, the detection circuit MSD shown in FIG. 14A has a terminal VC1 to which a predetermined potential VB1 is supplied. a wiring VB1_IN, a wiring VB2_IN to which a predetermined potential VB2 is supplied, a sampling signal The power supply terminal has a wiring SH_IN to which the power is supplied, and an output terminal S_OUT.

[0260] Here, the predetermined potential VB1 is a potential higher than the predetermined potential VB2, and the predetermined potential VB 2 is a potential higher than the potential of the terminal VSSS.

[0261] FIG. 14B shows the transistors 11 to 15 of the detection circuit MSD. It differs from FIG. 14A in that it has a port.

[0262] FIG. 14C shows the memory element 114 connected to the wiring VB1_IN and the terminal VSSS. 14B and the fact that the memory element 114 connected to the wiring VB2_IN is included. Also, in FIG. 14C, one of the source and drain of the transistor 11 and One of the source and drain of the transistor 13 and one electrode of the capacitance element C11 are connected to each other. The potential VB1 and the potential VB2 are electrically connected to the storage element 114. are respectively provided to the wiring VB1_IN and the wiring VB2_IN, Therefore, the potential VB1 and the potential VB2 can be supplied. The power supply of the voltage generating circuit can be turned off or put into a standby state.

[0263] The transistors 11 to 15 are n-channel transistors. In the detailed description, an example in which the detection circuit MSD is configured using n-channel transistors is shown. However, a p-channel transistor may be used. It would be easy for a person skilled in the art to change the transistor from the configured circuit diagram to a p-channel type. Since it is easy to understand, the explanation will be omitted.

[0264] In the detection circuit MSD, one of the source and drain of the transistor 11 is connected to the terminal V The other of the source and drain of the transistor 11 is electrically connected to the transistor SSS. One of the source and drain of transistor 12 and the source and drain of transistor 15 The gate of the transistor 11 is electrically connected to one of the wirings VB1_IN and VB2_IN. The other of the source and drain of transistor 12 and the The gate of the transistor 12 is electrically connected to the terminal VC1.

[0265] One of the source and drain of the transistor 13 is electrically connected to the terminal VSSS. The other of the source and drain of the transistor 13 is connected to the source and drain of the transistor 14. The transistor 50 is electrically connected to one of the drains and the inverting input terminal of the comparator 50. The gate of the transistor 13 is electrically connected to the wiring VB2_IN, and the source of the transistor 14 is The other of the source and drain of the transistor 14 and the gate of the transistor 14 are electrically connected to the terminal VC1. Connected.

[0266] The other of the source and drain of the transistor 15 is connected to the other end of the capacitance element C11. and a non-inverting input terminal of the comparator 50. The gate of the capacitor C11 is electrically connected to the wiring SH_IN, and one terminal of the capacitor C11 is connected to the terminal The output terminal of the comparator 50 is electrically connected to the output terminal S_OUT. One terminal of the capacitance element C11 is electrically connected to a wiring to which a predetermined potential is supplied. If so, it may be electrically connected to a wiring other than the terminal VSSS.

[0267] Here, the other of the source and drain of the transistor 11 and the source of the transistor 12 and one of the source and drain of transistor 15 are connected to the The electrically connected node is called node N11, and the source and drain of transistor 13 are connected to the other input, one of the source and drain of the transistor 14, and the comparator 5 The inverting input terminal of the transistor N1 is electrically connected to the node N12. the other terminal of the source and drain of the capacitor C15, the other terminal of the capacitor C11, and the The connection point to which the non-inverting input terminal of the inverter 50 is electrically connected is referred to as node N13.

[0268] The transistors 11 and 12 form a first source follower. The transistor 13 and the transistor 14 form a second source follower. The gate of the transistor 11 corresponds to the input of the first source follower. The gate of transistor 13 is connected to the input of the second source follower. Correspondingly, the second source follower outputs to node N12.

[0269] An example of the operation of the detection circuit MSD will be described using the circuit shown in FIG. 14C.

[0270] When charging starts in the battery pack, the sampling signal given to the line SH_IN is It becomes high level at predetermined intervals. A potential higher than the potential VB2 is given as the potential VB1. As the nodes N11 and N12 are charged, the potentials of the nodes N11 and N12 rise.

[0271] When a micro-short circuit occurs and the positive electrode potential drops instantaneously, the node N11 and The potential of the node N12 drops instantaneously. When the signal is at a low level, the potential of the node N13 is not affected by the potential of the node N11. The potential at node N12 becomes lower than the potential at node N13. Then, the output of comparator 50 becomes The voltage is reversed and a micro-short is detected.

[0272] In addition, to improve the accuracy of detecting micro-shorts, the voltage of the secondary battery is converted to analog and digital signals. The conversion circuit converts the data into digital data, and the digital data is then processed by a processor unit or the like. It performs calculations based on the data, analyzes the charging waveform or discharging waveform, and detects micro-shorts. Alternatively, a micro-short circuit may be predicted. For example, the waveform of the charge or discharge may be In this case, the deviation of the voltage error at each time step is used to detect or predict micro-short circuits. The voltage error displacement is calculated by calculating the voltage error and calculating the difference from the previous step. It is calculated by:

[0273] To improve the accuracy of detecting micro-shorts, a neural network may be used.

[0274] A neural network is a method, and the neural network part (e.g., CPU (Central Processor Unit), GPU (Graphics Pr Processing Unit)、APU(Accelerated Processing Unit)、APU(Accelerated Processing Unit) This is neural network processing performed by a neural network (including the arithmetic unit, memory, etc.). APU refers to a chip that integrates a CPU and a GPU into one.

[0275] The discharge of secondary batteries installed in devices is easily dependent on how they are used by the user. However, the charging conditions are fixed, so the charging time is shorter than the discharging time. It can be said that the curve is easy to predict. By using a certain number of charging curves as learning data, The neural network can predict the exact value. If it is possible to obtain the SOC (State of Charge) using a neural network, ) etc. The neural network calculations can be performed using a microprocessor, for example. etc. can be used.

[0276] Specifically, various data obtained is evaluated and learned using machine learning or artificial intelligence. The system analyzes the predicted degree of deterioration of the secondary battery, and if there is an abnormality, stops charging the secondary battery. Alternatively, the current density of constant current charging is adjusted.

[0277] For example, in an electric vehicle, learning data can be acquired while driving, and the deterioration state of the secondary battery can be monitored. It is possible to grasp the deterioration state of the secondary battery. A neural network is a neural network with multiple hidden layers. In other words, it can be constructed using a deep neural network. Learning in neural networks is sometimes called deep learning.

[0278] Machine learning first extracts feature values ​​from the training data. Extract the amount of data as feature values ​​and train the neural network based on the extracted feature values. The learning means trains the neural network based on different learning patterns for each time interval. The neural network can be trained based on the learning results of the training data. The connection weights applied to the network can be updated.

[0279] As a method for estimating the state of charge of a secondary battery using a neural network, a regression model is used. It can also be obtained by performing calculations using a filter such as a Kalman filter.

[0280] The Kalman filter is a type of infinite impulse response filter. It is a type of multivariate analysis, in which multiple independent variables are used in regression analysis. Regression analysis requires a large number of time series of observed values, while the The Leman filter can sequentially obtain optimal correction coefficients as long as a certain amount of data is accumulated. The Kalman filter can also be applied to non-stationary time series. .

[0281] As a method for estimating the internal resistance and state of charge (SOC) of a secondary battery, a nonlinear Kalman filter is used. Filters (specifically, unscented Kalman filters (also known as UKFs)) can be used. Also, an extended Kalman filter (also called EKF) can be used. SOC is This indicates the charging state (also called the charging rate), with 100% being fully charged and 0% being fully discharged. It is an indicator.

[0282] The initial parameters obtained by the optimization algorithm are set to n (n is an integer, for example, 50). Collect data for each group and use the data as training data for neural network processing. This allows for highly accurate estimation of SOC.

[0283] The learning system includes a teacher data creation device and a learning device. Create training data that the learning device will use when learning. Training data is data to be processed. The training data includes data with the same recognition target as the training data and the evaluation of the label corresponding to the data. The creation device includes an input data acquisition unit, an evaluation acquisition unit, and a teacher data creation unit. The acquisition unit may acquire the information from data stored in a storage device, or may acquire the information from a learning device via the Internet. The input data is data used for learning, and the secondary battery The training data does not have to be actual measurement data, but By varying the period parameters, we can create data that is close to actual measurements, and By using the specified characteristic database as training data, neural network processing is performed. The state of charge (SOC) can be estimated based on the charge and discharge characteristics of a certain battery. The neural network is then trained using the specified characteristic database as training data. By performing work processing, it is also possible to efficiently estimate the SOC of batteries of the same type.

[0284] When the secondary battery deteriorates, the initial parameter FCC changes significantly, which can lead to an error in SOC. Since there is a possibility that differences may occur, the initial parameters used in the calculation for SOC estimation were updated. The initial parameters to be updated may be optimized using data on charge / discharge characteristics that have been measured in advance. The algorithm calculates the regression model using updated initial parameters, e.g. By performing calculations using a Leman filter, it is possible to estimate the SOC with high accuracy even after deterioration. In this specification, calculation processing using a Kalman filter is referred to as a Kalman filter. This is also expressed as processing data.

[0285] The timing of updating the initial parameters can be arbitrary, but it is important to estimate the SOC with high accuracy. For this reason, it is preferable to update frequently, and it is preferable to update regularly and continuously. When the temperature of the secondary battery is high, deterioration may be more likely to occur if the SOC is high. In such a case, the secondary battery is discharged to lower the SOC, which prevents deterioration of the secondary battery. It is preferable to suppress the oxidation.

[0286] This embodiment mode can be combined with the descriptions of other embodiment modes as appropriate.

[0287] (Embodiment 6) This embodiment shows an example of the configuration of a comparator.

[0288] FIG. 15A shows an example of the configuration of the comparator 50 described in the previous embodiment. The comparator 50 includes transistors 21 to 25. , a wiring VBM_IN to which the negative electrode potential of the secondary battery is supplied, and a wiring VBP to which the positive electrode potential of the secondary battery is supplied. a wiring VBP_IN to which a predetermined potential VB3 is supplied, a wiring VB3_IN to which a predetermined potential VB3 is supplied, an input terminal C P1_IN, input terminal CM1_IN, output terminal CP1_OUT, and output terminal CM1 _OUT.

[0289] 15A is applied to the cell balance circuit 130 and the detection circuit 185. For example, in this case, the wiring VBP_IN is connected to the terminal VC1, and the wiring VBM_IN is connected to the terminal V From C2, potentials are connected to each other.

[0290] Here, the predetermined potential VB3 is a potential higher than the negative electrode potential VBM, and In the inverter 50, the positive potential VBP is a high power supply potential, and the negative potential VBM is a low power supply potential. do.

[0291] In the comparator 50, one of the source and drain of the transistor 21 is connected to a wiring VBM_IN, and the other of the source and drain of the transistor 21 is One of the source and drain of transistor 22 and the source and drain of transistor 24 The gate of the transistor 21 is electrically connected to one of the wiring VB3_I and the drain of the transistor 21. N.

[0292] The other of the source and drain of transistor 22 is connected to the source and drain of transistor 23. One of the drains of the transistor 2 is electrically connected to the output terminal CM1_OUT. The other of the source and drain of transistor 3 and the gate of transistor 23 are connected to wiring VBP_ The gate of the transistor 22 is electrically connected to the input terminal CP1_IN. is connected to.

[0293] The other of the source and drain of transistor 24 is connected to the source and drain of transistor 25. One of the drains of the transistor 2 is electrically connected to the output terminal CP1_OUT. The other of the source and drain of transistor 5 and the gate of transistor 25 are connected to wiring VBP_ The gate of the transistor 24 is electrically connected to the input terminal CM1_IN. is connected to.

[0294] Moreover, a plurality of circuits shown in FIG. 15A may be connected in parallel to be used as the comparator 50. That is, the output of the comparator shown in FIG. 15A is input to the next-stage comparator 50, A plurality of comparators may be connected together.

[0295] Note that the transistors included in the circuit shown in FIG. 15A are back-gate transistors as shown in FIG. 15B. A holding circuit 99 can apply a voltage to the back gate and hold it. In the holding circuit 99, one of the source and drain of the transistor 99a is connected to a terminal The other is connected to the back gate of transistor 22, the other is connected to the back gate of transistor 24. The capacitor 99b is electrically connected to the gate 99c and one electrode of the capacitor 99b.

[0296] In the holding circuit 99, a voltage to be applied to the back gate is applied to the terminal SH_99. When the transistor 99a is turned on, the back gates of the transistors 22 and 24 are connected to the After applying the voltage, the transistor 99a is turned off, and the voltage of the back gate By using an OS transistor as the transistor 99a, This means that the leakage current that flows between the source and drain when the device is off (hereinafter referred to as the off current) is extremely low. Therefore, a desired voltage is maintained on the back gates of transistors 22 and 24. It is possible.

[0297] The voltage applied to the terminal SH_99 is, for example, applied from a secondary battery 99f to a conversion circuit 99e. , after passing through the conversion circuit 99e, it is given to the boost circuit 99c, and boosted by the boost circuit 99c The boost circuit 99c receives a signal from the clock generation circuit 99d. The conversion circuit 99e, the boost circuit 99c, and the clock generation circuit 99d are connected to the OS transceiver 99. It can be configured using a transistor.

[0298] In the power storage device of one embodiment of the present invention, two or more secondary batteries may be provided over a substrate. A secondary battery (here, a first secondary battery) is used to share power from the power storage device with electronic devices, etc., which will be described later. In addition to the secondary battery 99f, a secondary battery 99f may be provided. 9f may have a smaller capacity than the first secondary battery, for example, 0.1 times or less, or It is less than 0.01 times.

[0299] FIG. 12B shows a clock signal supplied from a booster circuit 99c and a clock generating circuit 99d. 1 shows an example of the configuration of a lock buffer circuit 99g.

[0300] (clock buffer circuit) The clock buffer circuit 99g includes inverters 70 to 75 and terminals a1 to a3. The clock buffer circuit 99g generates signals CK1_cp, CKB1_cp, and Terminal a1 is the input terminal for the signal CLK_cp, and terminal a2 , a3 are output terminals for the signals CK1_cp and CKB1_cp. The power storage device of one embodiment of the present invention divides the frequency of a reference clock signal to generate a signal. The signal CK1_cp and the signal CKB1_cp may have a function to generate CLK_cp. are complementary clock signals.

[0301] (Boost circuit) The boost circuit 99c is a step-down charge pump, which steps down the potential GND to the potential Vcp The input potential is not limited to the potential GND. The boost circuit c includes transistors MN61 to MN65 and capacitance elements C61 to C65. The number of stages in the path 99c is five, but the number of stages is not limited to this.

[0302] This embodiment mode can be combined with the descriptions of other embodiment modes as appropriate.

[0303] (Embodiment 7) In this embodiment, examples of electronic devices using a power storage device of one embodiment of the present invention will be described with reference to FIGS. 17A to 17C. A power storage device of one embodiment of the present invention includes a secondary battery and The battery control circuit can be mounted on the same board, making it possible to miniaturize electronic devices. Furthermore, the safety of the secondary battery can be improved. Since it can be provided on a substrate, it has the advantage of being thin.

[0304] FIG. 16 illustrates an IC card, which is an example of an application device including a power storage device of one embodiment of the present invention. The thin-film secondary battery 300 in the power storage device receives power from the radio wave 3005. The IC card 3000 contains an antenna and IC 3004, A thin-film secondary battery 3001 is disposed on the IC card 3000. A management badge is attached to the IC card 3000. The ID 3002 and photo 3003 of the worker wearing the battery are displayed. The power stored in 1 can also be used to transmit signals such as authentication signals from the antenna.

[0305] The power storage device of one embodiment of the present invention has a display for displaying the ID 3002 and the photograph 3003. The display device may include, for example, a display unit and a driver circuit for supplying an image signal to the display unit. The driver circuit includes, for example, a plurality of OS transistors described in the above embodiment. In the power storage device of one embodiment of the present invention, a secondary battery and an OS transistor are connected to each other. Therefore, the drive circuit can be formed by using an OS transistor. By providing a path, it is possible to mount the secondary battery and the drive circuit, or at least the drive circuit, on the same substrate. Therefore, it is possible to make the IC card thinner, lighter, and more durable. This becomes possible.

[0306] The display device may be, for example, an active matrix display device. Trix display devices include reflective LCD displays, organic EL displays, and electronic paper. It is possible to display images (moving or still images) and time on an active matrix display device. The power for the active matrix display device is supplied from a thin-film secondary battery 3001. It is possible.

[0307] Since IC cards use plastic substrates, organic EL displays using flexible substrates are A display device is preferred.

[0308] Also, a solar cell may be provided in place of the photo 3003. Electric power can be generated and charged into the thin-film secondary battery 3001 .

[0309] Furthermore, thin-film secondary batteries are not limited to IC cards, but can also be used in wireless sensors mounted on automobiles. It can be used as a power source, a secondary battery for MEMS devices, etc.

[0310] FIG. 17A shows an example of a wearable device. In addition, when the user uses the device in his / her daily life or outdoors, the device must be splash-proof. Wired devices with exposed connectors for improved performance, water resistance, or dust resistance There is a demand for wearable devices that can be charged not only by battery but also wirelessly.

[0311] For example, a power storage device according to one embodiment of the present invention may be used in a glasses-type device 400 as shown in FIG. 17A. The eyeglass-type device 400 includes a frame 400a and a display unit 400. b. The temples of the curved frame 400a are provided with a secondary battery. By incorporating this, it is a lightweight eyeglass-type device with good weight balance and can be used continuously for a long time. By including the secondary battery according to one aspect of the present invention, It is possible to realize a configuration that can accommodate space saving associated with the miniaturization of the device.

[0312] In addition, the headset device 401 may be equipped with a secondary battery according to one embodiment of the present invention. The headset type device 401 includes at least a microphone unit 401a and a flexible The flexible pipe 401b has an earphone section 401c. A secondary battery may be provided in the earphone unit 401c. By incorporating a battery, a configuration that can accommodate space-saving due to the miniaturization of the housing can be realized. can be done.

[0313] In addition, a device 402 that can be directly attached to the body is equipped with a secondary battery according to one embodiment of the present invention. The device 402 can be mounted in a thin housing 402a. By providing the secondary battery of one embodiment of the present invention, It is possible to realize a configuration that can accommodate space saving associated with the miniaturization of the housing.

[0314] In addition, the power storage device of one embodiment of the present invention may be mounted on a device 403 that can be attached to clothing. The device 403 has a thin housing 403a in which a storage battery is mounted. By providing the secondary battery of one embodiment of the present invention, It is possible to realize a configuration that can accommodate space saving associated with the miniaturization of the housing.

[0315] In addition, the power storage device of one embodiment of the present invention can be mounted on the belt-type device 406. The belt-type device 406 includes a belt part 406a and a wireless power receiving part 406b. and a power storage device having a secondary battery can be mounted inside the belt portion 406a. By including the power storage device of one embodiment of the present invention, space can be saved by reducing the size of the housing. It is possible to realize a configuration that can respond to such changes.

[0316] The power storage device of one embodiment of the present invention can be mounted on the wristwatch device 405. The wristwatch type device 405 has a display unit 405a and a belt unit 405b. A power storage device can be provided in the belt portion 405a or the belt portion 405b. By providing a power storage device, a configuration that can accommodate space saving due to the miniaturization of the housing is realized. It is possible.

[0317] The display unit 405a displays not only the time but also various information such as incoming emails and phone calls. It is possible.

[0318] The wristwatch type device 405 is a wearable device that is worn directly on the wrist. Therefore, sensors for measuring the user's pulse, blood pressure, etc. may be installed. It is also possible to accumulate health-related data and manage health.

[0319] FIG. 17B shows a perspective view of the wristwatch type device 405 removed from the wrist.

[0320] A side view is shown in Fig. 17C. Fig. 17C shows a power storage device 91 having a secondary battery therein. The power storage device 913 is located at a position overlapping with the display portion 405a. It is compact and lightweight.

[0321] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0322] (Embodiment 8) In this embodiment, an electronic device including a power storage device of one embodiment of the present invention will be described with reference to FIGS. 18A and 18B. 18B and 19A to 19D. The device can provide a secondary battery and a battery control circuit on the same substrate, so that the electronic device This allows the secondary battery to be made smaller, and the safety of the secondary battery can be improved. The power storage device of this embodiment can be provided on a substrate, and therefore has the feature of being thin.

[0323] FIG. 18A shows a wristwatch-type mobile information terminal (also called a smart watch (registered trademark)) 70 7 shows a perspective view of the mobile information terminal 700. The mobile information terminal 700 includes a housing 701, a display panel 702, a clasp 70 3, has bands 705A, 705B, and operation buttons 711, 712.

[0324] The display panel may be, for example, an active matrix display device. Matrix display devices include reflective LCDs, organic EL displays, and electronic paper. There are cases where an active matrix display device displays an image (moving or still image) or time. The power for the active matrix display device can be supplied from a thin-film secondary battery. Alternatively, an organic EL display device using a flexible substrate may be used.

[0325] The display device has a display panel and a drive circuit that supplies an image signal to the display panel. The driver circuit may include a plurality of OS transistors, for example, as described in the above embodiment. In the power storage device of one embodiment of the present invention, a secondary battery and an OS transistor can be formed on the same substrate. Therefore, by providing the driver circuit using an OS transistor, Therefore, the secondary battery and the drive circuit, or at least a part of the drive circuit, are provided on the same substrate. Therefore, the portable information terminal according to one embodiment of the present invention can be made smaller, lighter, and more durable. This becomes possible.

[0326] A display panel 702 mounted on a housing 701 that also serves as a bezel has a rectangular display area. The display area is curved. The display panel 702 is flexible. It is preferable that the display area be non-rectangular.

[0327] The band 705A and the band 705B are connected to the housing 701. The clasp 703 is The band 705A and the housing 701 are connected via a pin, for example. The band 705B and the housing 701, as well as the band 70 The same applies to the connection between 5A and clasp 703.

[0328] FIG. 18B shows a perspective view of the band 705A. The band 705A has a power storage device. For the device, for example, the power storage device described in the above embodiment can be used. The positive electrode lead 751 of the secondary battery of the power storage device is embedded in the band 705A. The negative electrode lead 752 and the negative electrode lead 752 each partially protrude from the band 705A (see FIG. 18B). The positive electrode lead 751 and the negative electrode lead 752 are electrically connected to the display panel 702. The pins may also function as electrodes. and the display panel 702, and the negative lead 752 and the display panel 702, respectively. The band 705A and the housing 701 may be electrically connected via a pin that connects them. This simplifies the configuration at the connection between the band 705A and the housing 701. can.

[0329] The power storage device is flexible, so the band 705A can be formed integrally with the power storage device. For example, the electric storage device can be set in a mold corresponding to the outer shape of the band 705A. The material of the band 705A is poured into the mold, and the material is hardened to form the band shown in FIG. 18B. You can create the 705A.

[0330] When rubber material is used as the material for the band 705A, the rubber is hardened by heat treatment. For example, if fluororubber is used as the rubber material, heat treatment at 170°C for 10 minutes will When silicone rubber is used as the rubber material, it is cured at 150°C for 10 minutes. It is hardened by heat treatment.

[0331] The materials used for the band 705A include fluororubber, silicone rubber, and fluorosilicone. Examples include urethane rubber and urethane rubber.

[0332] The mobile information terminal 700 shown in FIG. 18A can have various functions. For example, it can display various information (still images, videos, text images, etc.) in the display area, Panel function, calendar, date or time display function, various software (program The function of controlling processing by the program, wireless communication function, and various computer Functions for connecting to computer networks, and for transmitting or receiving various data using wireless communication functions. The function of reading out the program or data recorded on the recording medium and displaying it in the display area. It may have the function of displaying, etc.

[0333] In addition, a speaker, a sensor (force, displacement, position, velocity, acceleration, angular velocity) Degrees, rotation speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, electricity Includes functions to measure pressure, power, radiation, flow rate, humidity, gradient, vibration, odor or infrared. The portable information terminal 700 may have a light-emitting element, a microphone, etc. The display panel 702 can be manufactured by using the above.

[0334] Although FIG. 18A shows an example in which the power storage device is included in band 705A, The band 705B may be made of the same material as the band 705A. Fees can be used.

[0335] 19A shows an example of a cleaning robot. The cleaning robot 6300 is a housing 630 1, a display unit 6302 arranged on the top surface, a plurality of cameras 6303 arranged on the side, and a brush 6 304, an operation button 6305, various sensors, etc. Although not shown, the cleaning robot The cleaning robot 6300 is equipped with tires, a suction nozzle, etc. It moves, detects dust 6310, and sucks up the dust from the suction port on the bottom. Cut.

[0336] For example, the cleaning robot 6300 analyzes the image captured by the camera 6303 and detects the walls, furniture, etc. It can also determine whether there are obstacles such as steps. If an object that is likely to get tangled in the brush 6304 is detected, the rotation of the brush 6304 is stopped. The cleaning robot 6300 includes a power storage device of one embodiment of the present invention and The power storage device according to one embodiment of the present invention is provided with a cleaning robot 63. 00, making the cleaning robot 6300 a highly reliable electronic device with a long operating time. It is possible.

[0337] FIG. 19B shows an example of a robot. The robot 6400 shown in FIG. Device 6409, illuminance sensor 6401, microphone 6402, upper camera 6403, A peaker 6404, a display unit 6405, a lower camera 6406 and an obstacle sensor 6407, It is equipped with a moving mechanism 6408, a computing device, etc.

[0338] The microphone 6402 has the function of detecting the user's voice and environmental sounds. The speaker 6404 has a function of emitting sound. Use the phone 6402 and speaker 6404 to communicate with the user. is possible.

[0339] The display unit 6405 has a function of displaying various information. The display unit 6405 can display information desired by the user. The display unit 6405 may be a detachable information terminal. By placing it in a fixed position on the robot 6400, charging and data transfer can be performed. This makes it possible.

[0340] The upper camera 6403 and the lower camera 6406 capture images of the surroundings of the robot 6400. The obstacle sensor 6407 also detects the obstacles by using the moving mechanism 6408. Robot 6 can detect the presence or absence of obstacles in its path as it moves forward. 400 uses an upper camera 6403, a lower camera 6406, and an obstacle sensor 6407. This allows the robot to recognize its surroundings and move safely.

[0341] The robot 6400 includes a power storage device 6409 according to one embodiment of the present invention and an electronic component. By using the power storage device of one embodiment of the present invention in the robot 6400, This makes the 6400 a highly reliable electronic device with a long operating time.

[0342] FIG. 19C shows an example of an air vehicle. The air vehicle 6500 shown in FIG. 19C has a propeller. 6501, a camera 6502, and a power storage device 6503, and has the function of flying autonomously. It has.

[0343] For example, image data captured by the camera 6502 is stored in the electronic component 6504. The child component 6504 analyzes image data and detects whether there are any obstacles when moving. The power storage device 6503 can estimate the remaining power from a change in the power storage capacity of the secondary battery. The aircraft 6500 includes a power storage device 6503 according to one embodiment of the present invention. By using the power storage device of one embodiment of the present invention in the aircraft 6500, 0 can be an electronic device with a long operating time and high reliability.

[0344] FIG. 19D shows an example of an automobile. An automobile 7160 includes a power storage device 7161, an engine The car 7160 has a steering system, tires, brakes, a steering mechanism, a camera, etc. The power storage device 7161 according to one embodiment of the present invention is provided in the power storage device 7161. By using it in the train 7160, the weight of the train can be reduced. The volume of the secondary battery can be reduced. Also, the automobile 7160 can be made to have a long driving range and be safe. This makes for a highly safe and reliable automobile.

[0345] This embodiment mode can be implemented in appropriate combination with other embodiment modes. [Explanation of symbols]

[0346] 11: transistor, 12: transistor, 13: transistor, 14: transistor, 15: transistor, 21: transistor, 22: transistor, 23: transistor, 24: transistor, 25: transistor, 50: comparator, 90: power storage device, 91 : Battery control circuit, 91a: circuit, 91b: circuit, 99: holding circuit, 99a: transistor , 99b: transistor, 100: positive electrode, 101: positive electrode active material layer, 103: positive electrode current collector, 110: substrate, 113: comparator, 114: memory element, 120: battery pack, 121: power supply a cell balance circuit; a resistor element; 132: transistor, 140: transistor, 150: transistor, 161: capacitor 162: transistor, 172: transistor, 182: logic circuit, 185: detection circuit 185a: detection circuit; 185c: circuit; 185d: circuit; 186: detection circuit; 200 : Secondary battery, 203: Solid electrolyte layer, 204: Negative electrode active material layer, 205: Negative electrode current collector, 20 6: protective layer, 210: negative electrode, 213: solid electrolyte layer, 215: positive electrode current collector, 300: transistor Transistor, 313: semiconductor region, 314a: low resistance region, 314b: low resistance region, 315 : insulator, 316: conductor, 320: insulator, 322: insulator, 324: insulator, 326 : Insulator, 328: Conductor, 330: Conductor, 350: Insulator, 400: Glasses-type device , 400a: frame, 400b: display unit, 401: headset type device, 401a : Microphone part, 401b: Flexible pipe, 401c: Earphone part, 402: Device 402a: housing, 402b: power storage device, 403: device, 403a: housing, 403 b: power storage device, 405: wristwatch type device, 405a: display unit, 405b: belt unit, 4 06: Belt-type device, 406a: Belt part, 406b: Wireless power receiving part, 50 0: transistor, 503: conductor, 512: insulator, 514: insulator, 520: insulator , 522: insulator, 524: insulator, 530: oxide, 530a: oxide, 530b: acid oxide, 530c: oxide, 540a: conductor, 540b: conductor, 542a: conductor, 5 42b: conductor, 543a: region, 543b: region, 544: insulator, 550: insulator, 560: conductor, 560a: conductor, 560b: conductor, 574: insulator, 580: insulator 580b: insulator; 581: insulator; 599: substrate; 600: capacitor; 610: conductor conductor, 610b: conductor, 611: insulator, 660: sensor element, 660a: conductor, 6 60b: layer, 660c: conductor, 700: mobile information terminal, 701: housing, 702: display panel Nel, 703: Clasp, 705A: Band, 705B: Band, 711: Operation button, 7 12: Operation button, 751: Positive electrode lead, 752: Negative electrode lead, 913: Power storage device, 30 00: IC card, 3001: Thin film secondary battery, 3002: ID, 3003: Photo, 30 04: IC, 3005: Radio wave, 6300: Cleaning robot, 6301: Housing, 6302: Surface Display unit, 6303: camera, 6304: brush, 6305: operation button, 6310: dust, 6400: Robot, 6401: Illuminance sensor, 6402: Microphone, 6403: Top camera, 6404: speaker, 6405: display, 6406: lower camera, 6407: Obstacle sensor, 6408: moving mechanism, 6409: power storage device, 6500: flying object, 6501 : Propeller, 6502: Camera, 6503: Power storage device, 6504: Electronic components, 7160: Automobiles, 7161: Energy storage devices

Claims

[Claim 1] a first battery cell, a comparison circuit, a control circuit, a first transistor, and a capacitance element; the comparison circuit has a first input terminal, a second input terminal, an output terminal, and a second transistor; one of the source and the drain of the first transistor is electrically connected to the second input terminal; the other of the source and the drain of the first transistor is electrically connected to one electrode of the capacitance element; the first transistor has an oxide semiconductor in a channel formation region; the second transistor has an oxide semiconductor in a channel formation region; a first electrode of the first battery cell electrically connected to a gate electrode of the second transistor and the first input terminal; the comparison circuit has a function of outputting a first signal corresponding to a comparison result between the potential of the first electrode and a desired reference potential from the output terminal to the control circuit; The control circuit is a power storage device having a function of controlling charging of the first battery cell in response to the first signal.

Images