Power storage unit

Abstract

To provide a power storage unit which operates in a wide temperature range from a low temperature to a high temperature.SOLUTION: The power storage unit includes a power storage device 300, a heater 400 which is provided adjacent to the power storage device, a temperature sensor 410 which is provided adjacent to at least one of the power storage device and the heater and detects the temperature of at least one of the power storage device and the heater, and a control circuit 570 which controls the heater to heat the power storage device without charging the power storage device when the temperature of the power storage device is lower than a first temperature and controls the power storage device to be charged without heating the power storage device when the temperature of the power storage device is higher than or equal to the first temperature.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present application relates to an electricity storage unit and a solar power generation unit. [Background technology]

[0002] In recent years, the motors of mobile terminals such as mobile phones and smartphones, and electric vehicles, etc. As a power source for this, a power storage device such as a lithium secondary battery is widely used (see Patent Document 1). (see). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-269426 Summary of the Invention [Problem to be solved by the invention]

[0004] Such mobile terminals and electric vehicles are used in a wide range of temperatures, from low to high. For this reason, the energy storage devices installed in these vehicles must be able to fully demonstrate their battery characteristics over a wide temperature range. It is required that

[0005] For example, the currently widely used lithium secondary batteries contain lithium cobalt oxide (LiCoO2 ) and lithium iron phosphate (LiFePO4), and the positive electrode contains active materials such as lithium ions. The negative electrode is made of a carbon material such as graphite that can absorb and release carbon, and the negative electrode is made of a material such as ethylene carbonate or diethyl ether. A solute consisting of lithium salts such as LiBF4 or LiPF6 is added to an organic solvent such as carbonate. It is composed of a non-aqueous electrolyte dissolved therein.

[0006] However, in such a storage battery device, especially in a storage battery device using a carbon material such as graphite as the active material of the negative electrode, At low temperatures, the electrical resistance of the negative electrode increases, causing the negative electrode potential to decrease. When the potential becomes negative, lithium dendrites (hereafter referred to as dendrites) are formed in the carbon material. This can lead to problems such as short circuits between electrodes and irreversible capacitance due to peeling of the active material. It is necessary to charge at an electrode potential where dendrites do not form. In this case, the resistance of the negative electrode As the resistance increases, a lower current is required for charging, allowing for faster charging. There is a problem that there is no.

[0007] A lithium battery that uses a carbon material for the negative electrode and ethylene carbonate as the solvent for the electrolyte. In this case, the solvent is reduced and decomposed during charging and discharging, and a passive film is formed on the surface of the negative electrode active material. Once the passive film is formed, further reduction decomposition of the electrolyte is suppressed, so the lithium-ion The ON insertion occurs preferentially, which allows the power storage device to operate stably.

[0008] However, when a power storage device in which a passive film is formed on the surface of the negative electrode active material is charged at a high temperature, This causes a problem that the dynamic coating is destroyed, which impairs the safety of the electricity storage device.

[0009] Furthermore, when a power storage device that uses a non-aqueous solvent as an electrolyte is charged at a high temperature, the power storage device may catch fire. There is a risk.

[0010] In view of the above, one aspect of the disclosed invention is to provide a method for producing a cellulose ester compound having a high thermal conductivity in a wide temperature range from low to high temperatures. An object of the present invention is to obtain a power storage unit that can operate safely. [Means for solving the problem]

[0011] One embodiment of the disclosed invention is a power storage device in which a heater is installed adjacent to the power storage device. It is a power storage unit that heats the device.

[0012] The power storage unit further includes a temperature sensor disposed adjacent to the power storage device for detecting the temperature of the power storage device. and a control circuit to which information on the temperature of the power storage device detected by the temperature sensor is input. A circuit controls the heater to turn on and off.

[0013] When charging the power storage device, the temperature of the power storage device is lower than a predetermined temperature (first temperature T1). If the power storage device is not charged, the control circuit inhibits charging of the power storage device and heats the power storage device with the heater.

[0014] The temperature lower than the first temperature is, for example, a temperature at which the dendrites are formed. By prohibiting charging at such low temperatures, short circuits between electrodes and peeling of the active material can be prevented. Problems such as the formation of irreversible capacity can be avoided. In addition, the resistance of the negative electrode does not increase, and high-speed It is possible to charge the battery.

[0015] When charging the power storage device, if the temperature of the power storage device is equal to or higher than a first temperature, the control circuit The power storage device is not heated by the heater, and the power storage device is allowed to be charged.

[0016] The control circuit is configured to allow the power storage device to be discharged regardless of the temperature of the power storage device.

[0017] As a heater, for example, PTC (Positive Temperature Coefficient) A thermistor can be used. PTC thermistors are resistors with large resistance changes. They are designed to operate at a specific temperature (Curie temperature). Thermistors have a positive temperature coefficient above which the electrical resistance increases sharply. Furthermore, when a current flows through a PTC thermistor, the resistance increases due to self-heating, and the current stops flowing. A PTC thermistor with such a positive temperature coefficient is made by adding a small amount of BaTiO3 It can be produced by adding rare earth elements or the like.

[0018] When using a PTC thermistor as a heater, set the Curie temperature Tc as the first temperature. and uses the PTC thermistor switching function to turn the heater on and off. In this case, the temperature sensor is not necessarily required. A configuration not having such a function is also one aspect of the disclosed invention.

[0019] Here, it is recommended to use a PTC thermistor with a Curie temperature Tc of 0°C or higher and 10°C or lower. Specifically, it is recommended to set the temperature at approximately 5°C.

[0020] Furthermore, a heater whose resistance is almost constant regardless of temperature may be used as the heater.

[0021] When charging the power storage device, it is preferable to use only constant current charging, not constant voltage charging. If voltage charging is performed at high temperatures (e.g., above 60°C), the charging time will be longer and the electrolyte will Because it deteriorates.

[0022] Furthermore, when the temperature of the power storage device reaches a second temperature T2 that is higher than the first temperature, the control circuit In order to prevent deterioration of the electrolyte and destruction of the power storage device, charging may be prohibited. The temperature at which the passive film is destroyed by charging can be determined by the user. , the temperature at which the power storage device ignites.

[0023] As a result, the power storage device can be charged within the optimum temperature range, and the power storage device is prevented from being destroyed or malfunctioning. It is possible to suppress the deterioration of operation and capacity.

[0024] In one embodiment of the disclosed invention, a power storage device is a lithium battery using a carbon material as a negative electrode active material. The battery is characterized by being a lithium secondary battery.

[0025] One embodiment of the disclosed invention is a power storage device including the above power storage unit and a solar cell. The solar power generation unit is characterized in that the power generated by the solar cell is stored. do. [Effects of the Invention]

[0026] One aspect of the disclosed invention allows safe operation over a wide temperature range from low to high. Therefore, it is possible to obtain a power storage unit that can [Brief explanation of the drawings]

[0027] [Figure 1] 1A and 1B are diagrams illustrating a power storage device. [Figure 2] FIG. 2 is a diagram illustrating a power storage unit. [Figure 3] 1A and 1B are circuit diagrams of a power storage unit, a graph showing the temperature dependence of the heater's electrical resistance, and a graph showing the relationship between temperature and the transistor's gate voltage VGS. [Figure 4] FIG. 10 is a diagram showing the operation of the electricity storage unit when the temperature is lower than the Curie temperature Tc. [Figure 5] FIG. 10 is a diagram showing the operation of the electricity storage unit at or above the Curie temperature Tc. [Figure 6] FIG. 2 is a diagram illustrating a power storage unit. [Figure 7] 1A and 1B are a circuit diagram of a power storage unit and a diagram showing the relationship between temperature and voltage applied to a gate of a transistor; [Figure 8] FIG. 10 is a diagram showing the operation of the power storage unit when the temperature is lower than T1. [Figure 9] FIG. 10 is a diagram showing the operation of the power storage unit when the temperature is equal to or higher than T1. [Figure 10] FIG. 2 is a circuit diagram illustrating a power storage unit. [Figure 11] FIG. 2 is a circuit diagram illustrating a power storage unit. [Figure 12] FIG. 10 is a diagram showing the operation of the power storage unit when the temperature is lower than T1. [Figure 13] FIG. 10 is a diagram showing the operation of the power storage unit when the temperature is equal to or higher than T1. [Figure 14] FIG. 2 is a circuit diagram illustrating a power storage unit. [Figure 15] FIG. 2 is a circuit diagram illustrating a power storage unit. [Figure 16] Cross-sectional view of a solar power generation unit. [Figure 17] FIG. 2 is a circuit diagram illustrating a solar power generation unit. [Figure 18] FIG. 2 is a circuit diagram illustrating a solar power generation unit. [Figure 19] FIG. 2 is a circuit diagram illustrating a solar power generation unit. DETAILED DESCRIPTION OF THE INVENTION

[0028] Hereinafter, embodiments of the invention disclosed in this specification will be described with reference to the drawings. The invention disclosed herein can be embodied in many different forms, and Various changes in form and details may be made without departing from the spirit and scope of the invention disclosed herein. It will be readily understood by those skilled in the art that the present invention can be modified in various ways. In the drawings shown below, the same parts or similar functions are The same reference numerals are used to designate parts having the same functions, and the repeated explanations will be omitted. The same hatch pattern is used to refer to the following, and no specific symbol may be added.

[0029] In addition, the position, size, range, etc. of each component shown in the drawings may be changed to make the explanation easier to understand. Therefore, the actual location, size, range, etc. may not be shown. The details are not necessarily limited to the positions, sizes, ranges, etc. disclosed in the drawings.

[0030] In this specification, ordinal numbers such as "first," "second," and "third" are used to avoid confusion of components. The numbers are added to avoid confusion and are not intended to limit the number.

[0031] In addition, the terms "electrode" and "wiring" used in this specification and the like do not limit the functionality of these components. For example, an "electrode" may be used as part of a "wiring." Furthermore, the terms "electrode" and "wiring" are used interchangeably to refer to the plural "electrodes" and "wirings." This also includes cases where the "line" is formed as a single unit.

[0032] Also, the functions of "source" and "drain" may differ depending on whether transistors with different polarities are used or not. However, they may be swapped when the direction of current changes during circuit operation. In this specification, the terms "source" and "drain" can be used interchangeably. It shall be possible.

[0033] In this specification, "electrically connected" means "something that has some kind of electrical effect." This includes cases where the device is connected via a " is not subject to any particular restrictions as long as it enables the transmission and reception of electrical signals between connected objects. For example, "things that have some kind of electrical action" include electrodes, wiring, and transistors. These include switching elements, resistor elements, inductors, capacitors, and other various functions. This includes elements such as

[0034] In this specification, the terms "above" and "below" refer to the positional relationship of a component "directly above" or "below." For example, the term "gate electrode on a gate insulating film" does not necessarily mean "directly below." ", it excludes those that include other components between the gate insulating film and the gate electrode. do not have.

[0035] [Embodiment 1] This embodiment will be described below.

[0036] <Configuration of the power storage device> The power storage device of this embodiment will be described below.

[0037] 1(A) is a cross-sectional view of a power storage device 300. The power storage device 300 shown in FIG. A positive electrode 311 having a current collector 301 and a positive electrode active material layer 302, a negative electrode current collector 305 and a negative electrode active material layer A negative electrode 312 having a material layer 304 and a positive electrode 311 sandwiched between the negative electrode 312 The electrolyte 308 is a conductive material.

[0038] The positive electrode 311 is formed on the positive electrode current collector 301 by a CVD method, a sputtering method, or a coating method. The positive electrode active material layer 302 is formed by forming the positive electrode active material layer 302 .

[0039] The positive electrode current collector 301 is made of stainless steel, gold, platinum, zinc, iron, copper, aluminum, titanium, etc. Use materials that are highly conductive and do not alloy with lithium, such as metals and their alloys. In addition, heat-resistant materials such as silicon, titanium, neodymium, scandium, and molybdenum can be used. Aluminum alloys containing elements that improve the properties can be used. Metal elements that react with silicon to form silicides, such as zirconium, titanium, and hafnium , vanadium, niobium, tantalum, chromium, molybdenum, tungsten, cobalt, nickel The positive electrode current collector 301 may be formed in a foil, plate (sheet), mesh, punch, or other shape. The metal may have a shape such as a round metal or an expanded metal.

[0040] The positive electrode active material contained in the positive electrode active material layer 302 is capable of inserting carrier ions such as lithium ions. Any material that can be desorbed and released may be used, such as LiFeO2, LiCoO2, and LiNiO 2. Compounds such as LiMn2O4, V2O5, Cr2O5, and MnO2 can be used When the positive electrode active material layer 302 is formed by a coating method, a conductive additive or a binder is added to the positive electrode active material. The paste is then applied onto the positive electrode current collector 301 and fired.

[0041] As the positive electrode active material, a lithium-containing composite phosphate with an olivine structure (general formula LiMPO4( M is one or more of Fe(II), Mn(II), Co(II), and Ni(II). Representative examples include LiFePO4, LiNiPO4, LiCoPO4, and Li MnPO4, LiFe a Ni b PO4, LiFe a Co b PO4, LiFe a Mn b PO 4. LiNi a Co b PO4, LiNi a Mn b PO4(a+b is less than 1, 0 <a<1、 0 <b<1)、LiFe c Ni d Co e PO4, LiFe c Ni d Mn e PO4, LiN i c Co d Mn e PO4(c+d+e is less than 1, 0 <c<1、0<d<1、0<e<1) , LiFe f Ni gCo h Mn i PO4 (where f + g + h + i is less than or equal to 1, 0 < f < 1, 0 < g < 1, 0 < h < 1, 0 < i < 1) etc. can be mentioned.

[0042] As the positive electrode active material, the general formula Li (2-j) MSiO4 (M is one or more of Fe(II), Mn(II ), Co(II), Ni(II), 0 ≤ j ≤ 2) etc. of lithium-containing composite silicate can be used. Representative examples include Li (2-j) FeSiO4, Li (2-j) NiSiO4, Li (2-j) CoSiO4, Li (2-j) MnSiO4, Li (2- j) Fe a Ni b SiO4, Li (2-j) Fe a Co b SiO4, Li (2-j) Fe k 4]Mn l SiO4, Li[[ID=]47] (2-j) Ni k Co l SiO4, Li (2-j) Ni k Mn l SiO4 (where k + l is less than or equal to 1, 0 < k < 1, 0 < l < 1), Li (2-j) Fe m Ni n C o q [[ID=]69]SiO4, Li (2-j) Fe m Ni n Mn q SiO4, Li<000,0053>Ni m Co n Mn q SiO4 (where m + n + q is less than or equal to 1, 0 < m < 1, 0 < n < 1, 0 < q < 1), Li (2-j) Fe r Ni s Cot Mn u SiO4 (where r + s + t + u is 1 or less, 0 < r < 1, 0 < s < 1, 0 < t < 1, and < 0 < u < 1) etc. can be mentioned.

[0043] In addition, when the carrier ion is an alkali metal ion other than lithium ion (e.g., sodium or potassium etc.), an alkaline earth metal ion (e.g., calcium, strontium, barium ium etc.), beryllium ion, or magnesium ion, as the positive electrode active material, the metal phosphate or silicate may be used.

[0044] Note that the active material refers to a substance related to the insertion and extraction of ions that are carriers. When making an electrode a mixture of other materials such as a conductive assistant, a binder, and a solvent together with the active material is formed on a current collector as an active material layer. Therefore, the active material and the active material layer are distinguished. Therefore, the positive electrode active material and the positive electrode active material layer 302, as well as the negative electrode active material and the negative electrode active material layer 304 described later are distinguished.

[0045] When graphene is used as a conductive assistant in the positive electrode active material layer 302, it is particularly effective for constructing a highly electron - conductive electron conduction network.

[0046] Graphene is a carbon material having a crystal structure in which the hexagonal skeleton formed by carbon spreads two - dimensionally Graphene is obtained by extracting a single - atom layer of graphite.

[0047] Graphene may be formed in about 1 to 100 layers. Single - layer graphene is sometimes called a graphene sheet

[0048] In the positive electrode active material layer 302, graphene overlaps and contacts a plurality of positive electrode active material particles ​In this case, the positive electrode active material layer 302 may be dispersed so as to have electron conduction properties due to graphene. This forms a network for conducting the positive electrode active material particles together by graphene. The positive electrode active material layer 302 is linked by the electrons, and has high electron conductivity.

[0049] The binder contained in the positive electrode active material layer 302 is typically polyvinylidene fluoride. In addition to PVDF, polyimide, polytetrafluoroethylene, polyvinyl chloride, Ethylene propylene diene polymer, styrene-butadiene rubber, acrylonitrile-butadiene Diene rubber, fluororubber, polyvinyl acetate, polymethyl methacrylate, polyethylene, Nitrocellulose and the like can be used.

[0050] The negative electrode 312 is formed on the negative electrode current collector 305 by a CVD method, a sputtering method, or a coating method. The negative electrode active material layer 304 is formed by forming the negative electrode active material layer 304 .

[0051] The negative electrode current collector 305 is made of a metal such as aluminum, copper, nickel, or titanium, or Highly conductive materials such as aluminum-nickel alloy and aluminum-copper alloy can be used. The negative electrode current collector 305 may be in the form of a foil, a plate (sheet), a mesh, a punched metal, an expeller, or the like. It can have a shape such as a black metal.

[0052] The negative electrode active material contained in the negative electrode active material layer 304 is formed by dissolution and deposition of metal or metal ions. There are no particular limitations on the material as long as it is a material that allows insertion and desorption of the negative electrode active material. Lithium metal, carbon-based materials, silicon, silicon alloys, tin, etc. can be used. For example, powdered or fibrous graphite can be used as the carbon-based material. When the negative electrode active material layer 304 is formed by the method, a conductive additive or a binder is added to the negative electrode active material. The negative electrode paste is prepared by applying it onto the negative electrode current collector 305 and then drying it. As mentioned above, when graphene is used as a material, a highly conductive electron conduction network can be constructed. This is particularly effective because

[0053] Even when the negative electrode active material layer 304 is formed using silicon as the negative electrode active material, It is preferable to form graphene on the surface of the active material layer 304. Silicon is The volume change due to the absorption and release of carrier ions in the negative electrode current collector 30 is large. The adhesion between the negative electrode active material layer 304 and the negative electrode active material layer 5 is reduced, and the battery characteristics are deteriorated by charge and discharge. Therefore, when graphene is formed on the surface of the negative electrode active material layer 304 containing silicon, the charge / discharge capacity is improved. Even if the volume of silicon changes during the cycle, the volume of silicon formed on the surface of the negative electrode active material layer 304 remains constant. The graphene prevents a decrease in adhesion between the negative electrode current collector 305 and the negative electrode active material layer 304. This is preferable because it reduces the deterioration of the battery characteristics.

[0054] The negative electrode active material layer 304 may be pre-doped with lithium. As a method, a lithium layer may be formed on the surface of the negative electrode active material layer 304 by sputtering. Alternatively, by providing a lithium foil on the surface of the negative electrode active material layer 304, 04 can also be pre-doped with lithium.

[0055] The electrolyte 308 sandwiched between the positive electrode 311 and the negative electrode 312 has a solute and a solvent. A material with carrier ions is used as the solute. A typical example of the solute is LiCl. Lithium such as O4, LiAsF6, LiBF4, LiPF6, and Li(C2F5SO2)2N There is mu salt.

[0056] In addition, when the carrier ion is a metal ion other than a lithium ion, the solute is Salt may also be used.

[0057] As the solvent for the electrolyte, an aprotic organic solvent capable of transporting carrier ions is preferred. Representative examples include ethylene carbonate (EC), propylene carbonate, dimethyl Carbonate, diethyl carbonate (DEC), γ-butyrolactone, acetonitrile , dimethoxyethane, tetrahydrofuran, etc., and one or more of these may be used. In addition, by using a gelled polymer material as a solvent for the electrolyte, the leakage resistance can be improved. This improves safety against fires and other accidents. It also makes it possible to make the secondary battery thinner and lighter. Examples of such polymers include silicone gels, and other polymers with a main chain structure such as acrylic polymers and polyacrylic polymers. Lylonitrile, polyethylene oxide, polypropylene oxide, fluorine-based polymer In addition, ionic liquids (room-temperature molten salts) are used as the solvent for the electrolyte. One or more may also be used.

[0058] In addition, a solid electrolyte containing an inorganic material such as a sulfide or an oxide is used as the electrolyte 308. When a solid electrolyte is used, the entire battery can be solidified, eliminating the risk of leakage. This eliminates the need for wires and dramatically improves safety.

[0059] An example of a laminated power storage device will be described with reference to FIG.

[0060] The laminated power storage device 310 shown in FIG. 1B includes a positive electrode current collector 301 and a positive electrode active material a positive electrode 311 having a layer 302, and a negative electrode having a negative electrode current collector 305 and a negative electrode active material layer 304. The battery includes an electrode 312, a separator 307, an electrolyte 308, and an outer casing 309. A separator 307 is provided between a positive electrode 311 and a negative electrode 312 provided in the battery 9. The exterior body 309 is filled with an electrolyte 308 .

[0061] The separator 307 is made of cellulose (paper), or porous polypropylene, poly An insulator such as ethylene can be used. The separator 307 also contains an electrolyte 308. It is impregnated.

[0062] The positive electrode current collector 301 and the negative electrode current collector 305 also serve as terminals for electrical contact with the outside. Therefore, a part of the positive electrode current collector 301 and the negative electrode current collector 305 is covered with the outer casing 309. The casing is arranged so that it is exposed to the outside.

[0063] The outer casing 309 is made of, for example, polyethylene, polypropylene, polycarbonate, iono Aluminum, stainless steel, copper, nickel, etc. are applied to a film made of a material such as mer or polyamide. and a thin metal film having excellent flexibility is provided on the thin metal film, and a polyamide film is provided on the outer surface of the exterior body. Three-layer laminate film with insulating synthetic resin film such as acrylic resin and polyester resin Such a three-layer structure prevents the permeation of electrolyte and gas. At the same time, it ensures insulation and is electrolyte resistant.

[0064] Although a lithium secondary battery has been described as an example of the power storage device of this embodiment, As another example of the power storage device of this embodiment, an electric double layer capacitor is used. The electric double layer capacitor has the advantage that dendrites do not form even at low temperatures. be.

[0065] <Configuration of the energy storage unit> 2 shows the configuration of the power storage unit of this embodiment. The figure shows the power storage device 310, the heater 400, and the temperature sensor 410. Detailed explanation has been given above, so it will be omitted here. Although a type of power storage device 310 is used, other types of power storage devices may also be used. The temperature sensor 410 has a terminal 411a and a terminal 411b. It has 11b.

[0066] FIG. 2B shows the electric storage device 310, the heater 400, and the temperature sensor 410 inside the exterior body 500. 2(C) shows the power storage unit 310 and the heater 400 mounted in the exterior body 500. The power storage unit installed inside is shown.

[0067] In the power storage unit shown in FIG. 2B, the temperature sensor 410, the heater 400, the power storage device 3 The temperature sensors 10 are installed adjacent to each other inside the exterior body 500. , is installed to detect the temperature of the power storage device 310.

[0068] In the power storage unit shown in FIG. 2C, the temperature sensor 410 is not provided, and the heater 400 The power storage device 310 is installed inside the exterior body 500 .

[0069] For example, a PTC thermistor is used as the heater 400. In this embodiment, the heater 400 is a plate-shaped PTC. The thermistor is used to uniformly heat the power storage device 310. The PTC thermistor has a Curie temperature It is recommended to use a material with a Tc between 0°C and 10°C. Specifically, if Tc is approximately 5°C, good.

[0070] In addition, the heater 400 is not a PTC thermistor, but a heater whose resistance is almost constant regardless of temperature. Data may also be used.

[0071] The temperature sensor 410 may be, for example, an NTC thermistor (NTC: Negative Temperature Coefficient). NTC thermistors use the temperature coefficient. However, the temperature sensor 410 is an NTC thermistor whose resistance decreases as the temperature rises. The temperature sensor is not limited to a thermistor, and other types of temperature sensors may be used.

[0072] The temperature sensor 410 is installed adjacent to the power storage device 310. The temperature T of the device 310 is detected, and whether or not charging is allowed is controlled based on the temperature T. As shown in the figure, a PTC thermistor is used as the heater 400, and the temperature dependence of the resistance of the PTC thermistor is The battery may have a circuit configuration that controls whether charging is possible or not by utilizing the battery characteristics.

[0073] The exterior body 500 can accommodate the temperature sensor 410, the heater 400, and the power storage device 310. The exterior body 500 is a housing having a cavity. The material of the exterior body 500 is, for example, polyethylene, polypropylene, etc. It uses resins such as polyethylene, polycarbonate, ionomer, polyamide, paper, ceramic, etc. That's fine.

[0074] When a material having a heat insulating effect (for example, ceramic) is used as the material for the exterior body 500, the temperature can be reduced. This is suitable for use in high-temperature environments as it can efficiently retain heat without dissipating the heat from the heater 400 to the outside. be.

[0075] The terminals 501a and 501b of the exterior body 500 are connected to the positive electrode current collector 301 and the positive electrode current collector 301 of the power storage device 310. and the negative electrode current collector 305, or the positive electrode current collector 301 and It may also be the negative electrode current collector 305 itself.

[0076] The terminals 502a and 502b of the exterior body 500 are connected to the terminals 411a and 411b of the temperature sensor 410. It may be a terminal electrically connected to the terminal 411b, or it may be a terminal electrically connected to the terminal 411a and the terminal 411b. It may be b itself.

[0077] The terminals 503a and 503b of the exterior body 500 are connected to the terminals 401a and 401b of the heater 400. It may be a terminal electrically connected to terminal 401a and terminal 401b, or a terminal electrically connected to terminal 401a and terminal 401b. It may also be one of the following.

[0078] In the power storage unit shown in FIG. 2B, the temperature of the power storage device 310 is detected by a temperature sensor 410. Whether or not the power storage device 310 can be charged is controlled according to the temperature.

[0079] This prevents the power storage device 310 from being charged at low or high temperatures, and prevents dendrites. This can prevent the formation of cracks, destruction of the passivation film, and even the ignition of the electricity storage device 310.

[0080] The electricity storage unit is heated to a temperature below the temperature at which the passive film is destroyed, or 10 is used at a temperature that does not reach the temperature at which it ignites, and a PTC thermistor is used as the heater 400. When a temperature sensor 410 is installed, as in the case of the power storage unit shown in FIG. 2(C), In this case, the PTC thermistor's switching function allows the heater If the heater 400 becomes too hot, the heating can be automatically stopped.

[0081] [Embodiment 2] Below is a circuit that controls whether charging is possible or not using the temperature dependency of the electrical resistance of a PTC thermistor. This article explains:

[0082] <Circuit configuration> FIG. 3A shows a circuit diagram of a power storage unit when a PTC thermistor is used as the heater 400. A portion of the figure is shown.

[0083] The circuit 250 shown in FIG. 3A includes a power storage device 300, a temperature sensor 410, a PTC thermistor a heater 400 using the resistor 201, a transistor 202, a diode 203, and a terminal 21 1 and terminal 212.

[0084] The power storage device 300 may be the above-described power storage device 310, or a power storage device of another shape may be used. The positive electrode of the power storage device 300 is connected to the drain (D) of the transistor 202 and The negative electrode of the power storage device 300 is electrically connected to the anode of the diode 203. Electrically connected to one terminal of the sensor 410, one terminal of the resistor 201, and the terminal 212 The voltage applied between the positive and negative electrodes of the power storage device 300 is Vbt. The source and drain of a transistor may be swapped depending on the applied voltage. Here, to make it easier to understand the circuit configuration, we will assume that the charge The terminal with the higher potential is called the source, and the terminal with the lower potential is called the drain. In a transistor, the terminal with the higher potential is called the drain, and the terminal with the lower potential is called the source.

[0085] In the circuit 250 shown in FIG. 3A, an NTC thermistor is used as the temperature sensor 410. The temperature sensor 410 is electrically connected to the power storage device 300 and the heater 400. Moreover, it is installed adjacent to the power storage device 300 .

[0086] The other terminal of the temperature sensor 410 is electrically connected to the terminal THM.

[0087] The heater 400 is a PTC thermistor as described above, and one terminal is connected to a transistor 2. The heater is electrically connected to the gate (G) of the heater 202 and the other terminal of the resistor 201. The other terminal of 400 is connected to the source (S) of transistor 202 and the cathode (C) of diode 203. The electrode is electrically connected to the terminal 211 .

[0088] The transistor 202 is a p-channel transistor. The voltage applied between the gate and source is the gate voltage VGS.

[0089] The resistor 201 is a resistor having a resistance value Rs.

[0090] The relationship between temperature and resistance for the heater 400 and the resistor 201 is shown in FIG. 3(B). As shown in FIG. 3B, the resistance of the heater 400 increases rapidly at the Curie temperature Tc. On the other hand, the resistance value Rs of the resistor 201 remains almost constant even when the temperature changes.

[0091] FIG. 3C shows the state during charging (when a positive voltage is applied to terminal 211 and a negative voltage is applied to terminal 212). The relationship between temperature and gate voltage VGS of transistor 202 is shown. At low temperatures, the gate voltage VGS is higher than the threshold voltage Vth of transistor 202. A constant negative voltage is maintained, and the transistor 202 is in an off state. Curie temperature Tc At temperatures above the Curie temperature Tc, the gate voltage VGS decreases rapidly. S becomes a constant negative voltage that is sufficiently lower than the threshold voltage Vth, and the transistor 202 In the circuit 250, the drain of the transistor 202 is higher than the source of the transistor 202 (terminal 211). When the voltage of the drain (positive electrode of the power storage device 300) is lowered, the diode 203 is forward biased. Since a voltage is applied, the power storage device 300 is in a discharging state. By making the drain voltage higher than the source voltage, the power storage device 300 becomes chargeable. Since a reverse bias voltage is applied to the diode 203, the By turning it on or off, you can control whether charging is permitted or prohibited. explain.

[0092] <<Operation below the Curie temperature Tc>> In the circuit shown in FIG. 3(A), the operation when the temperature T is lower than the Curie temperature Tc is shown in FIG. In this embodiment, the Curie temperature Tc is set to 0° C. or more and 10° C. or less. For example, the temperature should be approximately 5°C.

[0093] In FIG. 4, the current during charging (when a positive voltage is applied to terminal 211 and a negative voltage is applied to terminal 212) is The two-dot chain line indicates the current during discharge, and the one-dot chain line indicates the temperature lower than the Curie temperature Tc. In this state, the power storage device 300 is not charged, but can be discharged.

[0094] When the heater 400 is placed at a temperature below the Curie temperature Tc, the resistance of the heater 400 decreases. (See FIG. 3(B)). Therefore, a current flows through the heater 400 and the resistor 201, The gate voltage VGS is a voltage according to the combined resistance of the heater 400 and the resistor 201, and the threshold When the threshold voltage Vth is exceeded (see Figure 3(C)), the transistor, which is a p-channel transistor, Starter 202 is in the OFF state.

[0095] In this state, the direction of current flow is the reverse direction of the diode 203, so that the current flows from the terminal 211 The path of the current from the power supply to the power storage device 300 is cut off, and the power storage device 300 is not charged. That is, charging of the power storage device 300 is prohibited.

[0096] As shown in FIG. 4, a current flows through terminal 211, heater 400, resistor 201, and terminal 212. As a result, the heater 400 generates heat and can heat the electricity storage device 300 .

[0097] When the heater 400 heats the electricity storage device 300 and the temperature reaches or exceeds the Curie temperature Tc, The resistance of the heater 400 increases, current stops flowing through the heater 400, and transistor 2 02 is turned on. This stops the heating by the heater 400 and also turns off the stored Charging is permitted to the device 300. This operation will be described in more detail below.

[0098] On the other hand, during discharging, the transistor 202 is in an off state, but the diode 203 is in a forward direction. Therefore, the discharge current from the power storage device 300 flows through the terminal 21. 2. Current flows through the power storage device 300, the diode 203, and the terminal 211.

[0099] <<Operation at temperatures above the Curie temperature Tc>> In the circuit 250 shown in FIG. 3A, the operation at a temperature T equal to or higher than the Curie temperature Tc is , as shown in Figure 5.

[0100] In FIG. 5, the current during charging (when a positive voltage is applied to terminal 211 and a negative voltage is applied to terminal 212) is The two-dot chain line indicates the current during discharge, and the one-dot chain line indicates the current during discharge. When the heater 400 is placed at a temperature of 1000 K, the resistance of the heater 400 increases (see FIG. 3(B)). No current flows through the resistor 400 and the resistor 201, and the gate voltage VGS of the transistor 202 is The voltage Vth becomes lower than the threshold voltage Vth (see FIG. 3(C)).

[0101] The transistor 202 is a p-channel transistor and is therefore turned on.

[0102] In the above state, the charging current flows in the reverse direction through diode 203, but transistor 202 Since it is in the on state, the charging current flows through the terminal 211, the transistor 202, the power storage device 300, and and terminal 212, and the power is stored in the power storage device 300. In other words, charging is permitted. .

[0103] During discharge, the transistor 202 is in an on state and the discharge current flows. The direction is the forward direction of the diode 203. The discharge current from the power storage device 300 flows through the transistor In other words, the discharge current from the power storage device 300 is , terminal 212, power storage device 300, transistor 202, diode 203, and terminal 2 11. In this way, the power stored in the power storage device 300 can be discharged.

[0104] <<Operation above the second temperature>> In the circuit 250 shown in FIG. 3(A), charging is permitted when the temperature T is equal to or higher than the Curie temperature Tc. Therefore, when the temperature T of the electricity storage device 300 is high enough to destroy the passivation film, Even if the temperature of the power storage device 300 becomes so high that it may catch fire, charging is permitted.

[0105] Therefore, the user sets a second temperature T2 as the upper limit of the temperature T of the power storage device 300. When the temperature T of the power storage device 300 detected by the sensor 410 reaches T2, This prevents the passive film from being destroyed and the stored This can prevent the electrical device 300 from catching fire.

[0106] As a result, it is possible to obtain a power storage unit that can operate safely at both low and high temperatures.

[0107] 6 shows a power storage unit including the circuit 250. The power storage unit further includes a current control circuit. 550 and a control circuit 570, and can be connected to a power source 561 and a load 562. It is possible.

[0108] The current control circuit 550 includes a capacitor 551, a resistor 552, a coil 553, and a diode 55 4. It has a transistor 555 and uses a step-down DC-DC converter for current control. It is a circuit.

[0109] One terminal of the capacitor 551 is connected to one terminal of the resistor 552 and one terminal of the coil 553. , is electrically connected to the terminal SENSE+ of the control circuit 570. When discharging, a load 562 is connected to one terminal of the capacitor 551. The other terminal of 51 is grounded.

[0110] The other terminal of resistor 552 is connected to terminal SENSE- of control circuit 570 and terminal 21 of circuit 250. 1. The voltage across both terminals of resistor 552 is controlled by control circuit 570. This is the same as the voltage across the SENSE+ and SENSE- terminals of the resistor. The current value of the current flowing through 552 can be measured.

[0111] The other terminal of the coil 553 is connected to the cathode of a diode 554 and the drain of a transistor 555. The power supply is electrically connected to the power input.

[0112] The anode of the diode 554 is grounded.

[0113] The transistor 555 is an n-channel transistor, and its gate is connected to a terminal of the control circuit 570. It is electrically connected to the GS.

[0114] The source of the transistor 555 is electrically connected to the power supply 561 when the power storage device 300 is being charged. can be.

[0115] The power supply 561 supplies power for charging the power storage device 300. The power supply 561 is a DC power supply In the case of an AC power source, an AC-DC converter is used. (also called AC-DC converter or AC-DC inverter) can be used.

[0116] The control circuit 570 detects the voltages at the terminals SENSE+ and SENSE-. The current flowing between the terminal SENSE+ and the terminal SENSE-, i.e., the current flowing through the resistor 552, The control circuit 570 measures the current value of the temperature sensor 410 input to the terminal THM. Based on the information (signal) from on: PWM) signal and input it from terminal GS to the gate of transistor 555. The current value of the current flowing through the resistor 552 is controlled by the Controlling the current between terminals 211 and 212 of circuit 250, more specifically Specifically, the charging current to the power storage device 300 or the discharging current from the power storage device 300 is controlled. This means that

[0117] At temperatures equal to or higher than temperature T2, control circuit 570 outputs the temperature signal from temperature sensor 41 0, the transistor 555 is turned on based on the information on the temperature T of the power storage device 300. The power supply is turned off, and charging of the power storage device 300 is prohibited.

[0118] As described above, according to this embodiment, it is possible to obtain a power storage unit that can operate safely at both low and high temperatures. can.

[0119] FIG. 14 shows a power storage unit having a configuration in which the temperature sensor 410 is omitted (see FIG. 2(C)). vinegar.

[0120] The temperature at which the passive film on the negative electrode of the power storage device 300 is destroyed or the power storage device 300 ignites. If the temperature is lower than this, the circuit shown in Figure 14 can be used to obtain the optimum It is possible to obtain a power storage unit that can be charged within a temperature range.

[0121] As described above, according to this embodiment, it is possible to obtain a power storage unit that can operate safely at low and high temperatures. Cut.

[0122] The structures, methods, and the like described in this embodiment may be combined as appropriate with the structures, methods, and the like described in other embodiments. They can be used in combination.

[0123] [Embodiment 3] In this embodiment, the heater 400 is not a PTC thermistor, but a resistor that has a constant resistance regardless of temperature. A power storage unit using a substantially constant heater and a temperature sensor will be described.

[0124] <Circuit configuration 1> FIG. 7A shows a part of the circuit of the power storage unit of this embodiment.

[0125] The circuit 260 shown in FIG. 7A includes a power storage device 300, a temperature sensor 410, a heater 400, a Transistor 261, diode 262, transistor 263, diode 264, terminal 2 21, terminal 222, terminal THM, and terminal HCON.

[0126] The positive electrode of the power storage device 300 is connected to the drain of the transistor 261 and the anode of the diode 262. The negative electrode of the power storage device 300 is electrically connected to one of the nodes of the temperature sensor 410. terminal, the source of transistor 263, the anode of diode 264, and terminal 222 The voltage applied between the positive and negative electrodes of the power storage device 300 is Vbt. .

[0127] One terminal of the heater 400 is connected to the source of the transistor 261 and the cathode of the diode 262. The other terminal of the heater 400 is electrically connected to the transformer 221. The drain of the resistor 263 is electrically connected to the cathode of the diode 264 .

[0128] In this embodiment, an NTC thermistor is used as the temperature sensor 410. 0 is installed adjacent to the power storage device 300. However, as will be described later, the temperature of the heater 400 In order to switch the operation, the power storage device 300, the heater 400, and the temperature sensor 410 The other terminal of the temperature sensor 410 is connected to the terminal T It is electrically connected to HM.

[0129] Transistor 261 is a p-channel type transist, and its gate is connected to the gate of transist 263 and electrically connected to terminal HCON. Transistor 263 is an n-channel type transist.

[0130] Fig. 7(B) shows the relationship between the voltage V applied to the gates of transist 261 and transist 263 (i.e., the voltage applied to terminal HCON) and the temperature. HCON Note that the temperature in Fig. 7(B) is the temperature T detected by temperature sensor 410.

[0131] When the temperature T is lower than the temperature T1, the voltage V HCON is set to a high-level voltage (denoted as "H"). Here, the high-level voltage (H) is a voltage higher than the threshold voltage of transist 26 1 which is a p-channel type transist, and the threshold voltage of transist 263 which is an n-channel type transist.

[0132] When the temperature T is equal to or higher than a predetermined temperature T1, the voltage V HCON is set to a low-level voltage (denoted as "L"). Here, the low-level voltage (L) is a voltage lower than the threshold voltage of transist 26 1 which is a p-channel type transist, and the threshold voltage of transist 263 which is an n-channel type transist. Note that the temperature T1 is an arbitrary temperature determined by the user. The details of the circuit operation will be described below.

[0133] <<Operation at a temperature lower than T1>> In the circuit 260 shown in Fig. 7(A), the operation at a temperature T lower than the temperature T1 is shown in Fig. 8. <000088a>shown.​

[0134] In FIG. 8, the current when a positive voltage is applied to terminal 221 and a negative voltage is applied to terminal 222 is indicated by a two-dot chain line. The current during discharge is indicated by a dashed line.

[0135] When the temperature is lower than T1, the voltage V HCON is the high level voltage (H) (Fig. 7(B) When a high-level voltage (H) is applied to the gate, the p-channel transistor The transistor 261 is in an off state, and the transistor 263, which is an n-channel transistor, is in an off state. It becomes the ON state.

[0136] In this case, current flows through terminal 221, heater 400, transistor 263, and terminal 222. The direction of the current flow is the reverse direction of the diode 264. Therefore, the heater 400 generates heat and heats the power storage device 300. This can be done.

[0137] Also, the transistor 261 is in an off state, and the direction of current flow is the reverse of the direction of the diode 262. Since the direction of the current is the same as the direction of the current flow, the path of the current to the power storage device 300 is cut off, and the power storage device 300 is not charged. I can't.

[0138] When the heater 400 heats the electricity storage device 300 and the temperature of the electricity storage device 300 reaches or exceeds the temperature T1, Then, the heater 400 stops heating, and charging of the power storage device 300 is permitted. More on this later.

[0139] On the other hand, during discharging, the direction of the discharge current is the di- That is, the discharge current from the power storage device 300 flows through the terminal 222, It flows into the power storage device 300, the diode 262, and the terminal 221. Thus, the power storage device can discharge from 300.

[0140] <<Operation at a temperature of T1 or higher>> In the circuit 260 shown in FIG. 7(A), the operation at a temperature T of T1 or higher is shown in FIG. 9.

[0141] In FIG. 9, the current during charging (when a positive voltage is applied to terminal 221 and a negative voltage is applied to terminal 222) is shown by a two-dot chain line, and the current during discharging is shown by a one-dot chain line.

[0142] When the temperature is at a temperature of T1 or higher, the voltage V HCON is set to a low-level voltage (L) (see FIG. 7(B)). When the low-level voltage (L) is applied to the gate, the transistor 261, which is a p-channel transistor, is in the on state, and the transistor 263, which is an n-channel transistor, is in the off state. Since the transistor 263 is in the off state and the direction of the current flow is the reverse direction of the diode 2 64, no current flows through the heater 400.

[0143] When charging is performed in the above state, although the transistor 261 is in the on state, the direction of the charging current flow is the reverse direction of the diode 262, so the path of the charging current from the terminal 221 to the power storage device 300 passes only through the transistor 261. The charging current flows through the terminal 221, the source and drain of the transistor 26 1, the power storage device 300, and the terminal 222, whereby the power storage device 300 is charged. -

[0144] direction is the forward direction of the diode 262. The discharging current from the power storage device 300 is the transistor ​It passes through both the transistor 261 and the diode 262. That is, the discharge current from the power storage device 300 is , flows through the terminal 222, the power storage device 300, the source and drain of the transistor 261, the diode 262, and the terminal 221. Thus, it is possible to discharge from the power storage device 300.

[0145] <<Operation at a temperature of T2 or higher>> In the circuit 260 shown in FIG. 7(A), charging is permitted at a temperature of T1 or higher as described above. Therefore, even if the temperature T of the power storage device 300 becomes a high temperature at which the passive film is broken or a high temperature at which the power storage device 300 may catch fire, charging is permitted.

[0146] Therefore, the user sets the upper limit value (upper limit temperature T2) of the temperature T of the power storage device 300, and when the temperature of the power storage device 300 detected by the temperature sensor 410 reaches T2, charging of the power storage device 300 is prohibited. Thereby, it is possible to prevent the passive film from being broken and the power storage device 300 from catching fire.

[0147] As described above, a power storage unit that can operate safely at both low and high temperatures can be obtained.

[0148] FIG. 10 shows the circuit of the power storage unit including the circuit 260. The power storage unit has the circuit 260, the current control circuit 550, and the control circuit 580.

[0149] The control circuit 580 receives the information of the temperature sensor 410 at the terminal THM, and based on the information, switches the voltage V HCON of the terminal HCON to a high-level voltage (H) or a low-level voltage (L). Also, by detecting the voltages of the terminals SENSE+ and SENSE-, the terminal SEN ​​​​The current flowing between the SE+ and SENSE- terminals, i.e., the current flowing through resistor 552 Also, a power supply is connected from the terminal GS of the control circuit 580 to the gate of the transistor 555. By inputting a pulse width modulation signal, the current value of the current flowing through resistor 552 is controlled.

[0150] At temperatures lower than temperature T1 and at temperatures equal to or higher than temperature T2, control circuit 580 Based on the temperature T information of 00, the voltage V HCON A high level voltage is applied to transistor 261 and 263 to the gate of the power storage device 300, thereby prohibiting charging of the power storage device 300. Also, the pulse width modulation signal By controlling the transistor 555 to be in an off state, the power storage device 3 Charging to 00 can be prohibited.

[0151] At temperatures equal to or higher than upper limit temperature T2, control circuit 580 performs the following operation based on information on temperature T of power storage device 300. The pulse width modulation signal is controlled to turn off the transistor 555, and the stored charge is drawn from the power supply 561. Charging to device 300 may be prohibited.

[0152] <Circuit configuration 2> The following describes a power storage unit having a circuit configuration different from that shown in FIG. 7(A) and FIG. 10. do.

[0153] The circuit 270 shown in FIG. 11 is a circuit obtained by adding the gate of the transistor 261 to the circuit 260 shown in FIG. The difference is that the terminal is electrically connected to terminal CCON instead of terminal HCON. That is, in the circuit 260 of FIG. 7A, the gate of the transistor 261 and the gate of the transistor 263 The voltages applied to the gates of the transistors 11 and 12 are applied to the same terminal HCON. This is done at terminals CCON and HCON.

[0154] <<Operation at a temperature lower than T1>> In the circuit 270 shown in FIG. 11, the operation when the temperature T is lower than T1 is shown in FIGS. 12(A) and FIG. 12(B).

[0155] In FIG. 12(A), the current when a positive voltage is applied to terminal 221 and a negative voltage is applied to terminal 222 is shown by a two-dot chain line, and in FIG. 12(B), the current during discharge is shown by a one-dot chain line.

[0156] As shown in FIG. 12(A), a positive voltage is applied to terminal 221 and a negative voltage is applied to terminal 222, and the voltage V HCON is set to a high-level voltage (H), and the voltage V CCON is set to a high-level voltage (H). <000!011> When the high-level voltage (H) is applied to the gate, the transistor 261, which is a p-channel type transistor, is in the off state, and the transistor 263, which is an n-channel type transistor, is in the on state. becomes the on state.

[0158] In this case, current flows through terminal 221, heater 400, transistor 263, and terminal 222. Since the direction of the current flow is the reverse direction of diode 264, no current flows through diode 264. Therefore, the heater 400 generates heat and can heat the power storage device 300. Also, since transistor 261 is in the off state, the current path to the power storage device 300 is cut off, and the power storage device 300 is not charged.

[0159] On the other hand, as shown in FIG. 12(B), during discharge, the voltage V HCON is set to a high-level voltage (H), and the voltage V CCON is set to a low-level voltage (L). )]]

[0160] ​​​​​When a low-level voltage (L) is applied to the gate, the transistor 261, which is a p-channel type transistor, turns on. When a high-level voltage (H) is applied to the gate, the transistor 263, which is an n-channel type transistor, turns on. When discharging, the transistor 261 is in the on state, and the direction in which the discharge current flows is the forward direction of the diode 262. That is, the discharge current from the power storage device 300 flows through the terminal 222, the power storage device 300, the diode 262, and the terminal 221. Thus, the power storage device 300 can discharge.

[0161] [[ID=ll]] [[ID=I6]]

[0162] Here, the advantages of the circuit 270 shown in FIG. 11 with respect to the circuit '260 shown in FIG. 7(A) will be described.

[0163] In the circuit 260 shown in FIG. 7(A), in order to turn off the transistor 261 during discharge at a temperature lower than T1, the discharge current flows only through the diode 262. Due to the forward voltage drop of the diode 262, there is a risk that part of the power stored in the power storage device 300 will be lost during discharge.

[0164] On the other hand, in the circuit 270 shown in FIG, 11, the transistor 261 is turned on during discharge at a temperature lower than the temperature T1. Therefore, the discharge current flows through both the diode 262 and the transistor 261. As a result, the forward voltage drop of the diode 262 does not occur, and the loss of power stored in the power storage device 300 can be suppressed.

[0165] <<Operation at Temperatures above T1>> In the circuit 270 shown in FIG. 11, the operation at a temperature T of T1 or higher is shown in FIG. 13.

[0166] ​​​​​​​​​​​​ In FIG. 13, the current during charging (when a positive voltage is applied to terminal 221 and a negative voltage is applied to terminal 222) is shown by a two-dot chain line, and the current during discharging is shown by a one-dot chain line. When the temperature T is T1 or higher, the voltage V HC ON is set to a low-level voltage (L). When the low-level voltage (L) is applied to the gate, the transistor 263, which is an n-channel type transistor, turns off. Also, the voltage V of terminal CCON CCON is also set to the low-level voltage (L). When the low-level voltage (L) is applied to the gate , the transistor 261, which is a p-channel type transistor, turns on. Therefore, the direction in which the charging current flows is the forward direction of the diode 262. Since the transistor 263 is in the off state and the direction in which the charging current flows is the reverse direction of the diode 264, no current flows through the heater 400 .

[0167] When charging is performed in the above state, although the transistor 261 is in the on state, the direction in which the charging current flows is the reverse direction of the diode 262. Therefore, the charging current flows through the terminal 221, the transistor 2 61, the power storage device 300, and the terminal 222, and the power storage device 300 is charged [[ID=3O]] .

[0168] Also, during discharging, in addition to the transistor 261 being in the on state, the direction in which the discharging current flows is the forward direction of the diode 262. The path of the discharging current from the power storage device 300 is the terminal 222, the power storage device 300, the transistor 261, the diode 262, and the terminal 221 flows through. Thus, the power storage device 300 can discharge.

[0169] <<Operation at Temperatures of T2 or Higher>> In the circuit 270 shown in FIG. 11, charging is permitted at temperatures equal to or higher than the temperature T1, as described above. In this case, the temperature T of the electricity storage device 300 is high enough to destroy the passivation film, or Charging is permitted even if the electrical device 300 reaches a temperature that could cause a fire.

[0170] Therefore, the user sets the upper limit value (upper limit temperature T2) of the temperature T of the power storage device 300, and the temperature sensor When the temperature of the power storage device 300 detected by the sensor 410 reaches T2, the power storage device 300 This prevents the passive film from being destroyed and the power storage device 300 from generating electricity. It can prevent fires.

[0171] As a result, it is possible to obtain a power storage unit that can operate safely at both low and high temperatures.

[0172] 15 shows a circuit of a power storage unit including a circuit 270. The power storage unit shown in FIG. It includes a circuit 270, a current control circuit 550, and a control circuit 590.

[0173] The control circuit 590 receives information from the temperature sensor 410 at the terminal THM, and based on the information, Voltage V at terminal HCON HCON Switches to high level voltage (H) or low level voltage (L) Furthermore, the control circuit 590 controls the voltage ( Voltage V CCON (hereinafter referred to as "high level voltage") is switched to a high level voltage (H) or a low level voltage (L).

[0174] The control circuit 590 detects the voltages at the terminals SENSE+ and SENSE-. The current flowing between the terminal SENSE+ and the terminal SENSE-, i.e., the current flowing through the resistor 552, The current value of the current is measured. By inputting a pulse width modulation signal to the resistor 552, the current value flowing through the resistor 552 is controlled. do.

[0175] At a temperature equal to or higher than upper limit temperature T2, control circuit 590 performs The pulse width modulation signal is used to turn off transistor 555 and draw stored power from power supply 561. Charging of the electrical device 300 is prohibited.

[0176] As described above, according to this embodiment, it is possible to obtain a power storage unit that can operate safely at low and high temperatures. Cut.

[0177] The structures, methods, and the like described in this embodiment may be combined as appropriate with the structures, methods, and the like described in other embodiments. They can be used in combination.

[0178] [Embodiment 4] In this embodiment, an example will be described in which a solar cell is used as a power source for storing power in a power storage device. I will explain.

[0179] An example of a solar power generation unit 100 in which the power storage unit of this embodiment is combined with a solar cell. is shown in Figure 16.

[0180] The solar power generation unit 100 shown in FIG. 16 includes a power storage device 300, a heater 400, and a temperature The power storage unit includes a sensor 410, a solar cell 200, and a control device 600. The power storage unit is provided on the surface opposite to the light receiving surface of the solar cell 200. The power storage unit and the control device 600 are electrically connected by a wiring 403. .

[0181] The circuit configuration of the solar power generation unit 100 is shown in FIG. A circuit 250 (see FIG. 3(A)) using a PTC thermistor as the sensor 400. Let's say.

[0182] The solar power generation unit 100 includes a solar cell 200, a resistor 611, a resistor 612, an MPPT circuit 650 (MPPT: Maximum Power Point Tracking The power point tracking circuit 550 includes a current control circuit 550, a circuit 250, and a control circuit 670. The current control circuit 550 and the circuit 250 have the same configuration as shown in FIG.

[0183] One terminal of the resistor 611 is electrically connected to one terminal of the solar cell 200. The other terminal of 611 is connected to one terminal of resistor 612 and to terminal VIN_ of control circuit 670. The other terminal of resistor 612 is electrically connected to SNS.

[0184] The voltage of the DC power generated by the solar cell 200 is V SB Then, resistor 611 and resistor 612 are If the resistance values ​​of these resistors are R1 and R2, the voltage applied to the terminal VIN_SNS is R2 / R2. (R1+R2)×V SB Therefore, the voltage applied to the terminal VIN_SNS is detected. By doing so, the voltage V of the DC power generated by the solar cell 200 SB It can detect do.

[0185] The MPPT circuit 650 includes a capacitor 651, a resistor 652, a coil 653, and a diode 65 4. It has a transistor 655 and uses a step-down DC-DC converter for current control. It is a circuit.

[0186] One terminal of the capacitor 651 is connected to the current control circuit 550, one terminal of the resistor 652, and the control The other terminal of the capacitor 651 is electrically connected to the terminal SENSE1- of the circuit 670. The terminal is grounded.

[0187] The other terminal of the resistor 652 is connected to one terminal of the coil 653 and the terminal SENS of the control circuit 670. The voltage across both terminals of resistor 652 is electrically connected to E1+. This is the same as the voltage applied to the terminals SENSE1+ and SENSE1- of 70. This allows the current value of the current flowing through resistor 652 to be measured.

[0188] One terminal of the coil 653 is electrically connected to the other terminal of the resistor 652. The other terminal of the diode 653 is connected to the cathode of the diode 654, the source of the transistor 655, or The anode of the diode 654 is electrically connected to one of the drains. There are.

[0189] The transistor 655 is an n-channel transistor, and its gate is connected to a terminal of the control circuit 670. GS1 from the control circuit 670 to the gate of the transistor 655. By inputting a pulse width modulation signal, the current value of the current flowing through the resistor 652 is controlled. It is possible.

[0190] The other of the source and drain of the transistor 655 is electrically connected to one terminal of the resistor 611. is connected.

[0191] The voltage V of the DC power generated by the solar cell 200 SB changes depending on the state of the solar cell 200 Therefore, the MPPT circuit 650 controls the voltage V SB By changing the current value according to The amount of power that can be extracted from the solar cell 200 can be maximized.

[0192] For a detailed description of the current control circuit 550 and the circuit 250, see the current control circuit shown in FIG. The explanations of the circuit 550 and the circuit 250 can be used. However, in FIG. 17, The terminals GS, SENSE+, and SENSE- of the control circuit 570 are connected to the control circuit shown in FIG. This should be read as terminal GS2, terminal SENSE2+, and terminal SENSE2- of 670.

[0193] 14, the temperature at which the passive film is destroyed or the electricity storage device 300 ignites is also If the temperature is lower than the temperature, the temperature sensor 41 in the circuit 250 of FIG. The 0 may be omitted.

[0194] FIG. 18 shows a circuit configuration of a solar power generation unit having a different configuration from that shown in FIG. The power generating unit 100 includes a circuit 260 that uses a heater 400 whose resistance is almost constant regardless of temperature. (See FIG. 7(A)).

[0195] The solar power generation unit 100 includes a solar cell 200, a resistor 611, a resistor 612, an MPPT circuit 650, current control circuit 550, circuit 260, and control circuit 680. The battery 200, resistors 611 and 612, and MPPT circuit 650 have the same configuration as shown in FIG. However, the control circuit 670 shown in FIG. 17 is replaced with a control circuit 680 in FIG. 18. .

[0196] The current control circuit 550 and the circuit 260 have the same configuration as shown in FIG. The terminal GS, the terminal SENSE+, and the terminal SENSE- of the control circuit 580 of FIG. These are replaced with terminal GS2, terminal SENSE2+, and terminal SENSE2− of control circuit 680.

[0197] FIG. 19 shows a circuit configuration of a solar power generation unit having a different configuration from those shown in FIGS. 17 and 18. The solar power generation unit 100 uses a heater 400 whose resistance is almost constant regardless of temperature. The circuit 270 (see FIG. 11) is assumed to have:

[0198] The solar power generation unit 100 includes a solar cell 200, a resistor 611, a resistor 612, an MPPT circuit 650, current control circuit 550, circuit 270, and control circuit 690. The battery 200, resistors 611 and 612, and MPPT circuit 650 have the same configuration as shown in FIG. However, the control circuit 670 shown in FIG. 17 is replaced with a control circuit 690 in FIG. .

[0199] The current control circuit 550 and the circuit 270 have the same configuration as shown in FIG. The terminals GS, SENSE+, and SENSE- of the control circuit 590 of FIG. These are replaced with the terminal GS2, the terminal SENSE2+, and the terminal SENSE2− of the control circuit 690.

[0200] The structures, methods, and the like described in this embodiment may be combined as appropriate with the structures, methods, and the like described in other embodiments. They can be used in combination. [Explanation of symbols]

[0201] 100 solar power generation units 200 solar cells 201 Resistance 202 Transistor 203 Diode 211 terminal 212 terminals 221 terminal 222 terminal 250 circuits 255 circuits 260 circuits 261 Transistor 262 Diode 263 Transistor 264 Diode 270 circuits 300 Electricity storage device 301 Positive electrode current collector 302 Cathode active material layer 304 Negative electrode active material layer 305 Negative electrode current collector 307 Separator 308 Electrolyte 309 Exterior body 310 Electricity storage device 311 Positive electrode 312 negative electrode 400 heater 403 Wiring 401a terminal 401b terminal 410 Temperature Sensor 411a terminal 411b terminal 500 exterior body 501a terminal 501b terminal 502a terminal 502b terminal 503a terminal 503b terminal 550 Current control circuit 551 Capacitor 552 Resistance 553 Coil 554 Diode 555 transistor 561 Power supply 562 Load 570 Control Circuit 580 Control Circuit 590 Control Circuit 611 Resistance 612 Resistance 650 MPPT circuit 651 Capacitor 652 Resistance 653 Coil 654 Diode 655 Transistor 670 Control Circuit 680 Control Circuit 690 Control Circuit

Claims

[Claim 1] a power storage device; a heater installed adjacent to the power storage device; a temperature sensor arranged adjacent to at least one of the power storage device and the heater, detecting a temperature of at least one of the power storage device and the heater; and a control circuit that, when the temperature of the power storage device is lower than a first temperature, does not charge the power storage device and performs control to heat the power storage device using the heater, and, when the temperature of the power storage device is equal to or higher than the first temperature, does not heat the power storage device using the heater and performs control to charge the power storage device.

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