JP5414432B2 - Power storage system - Google Patents

Description

  The invention disclosed in this specification relates to a power storage system including a safety mechanism against internal gas generation.

  In recent years, technological development of power storage devices such as secondary batteries and capacitors has been promoted.

  However, when the electrolytic solution of a power storage device such as a secondary battery or a capacitor is decomposed due to a high temperature or overcharge, gas may be generated from the electrolytic solution.

  When gas is generated, the internal pressure of the electricity storage device increases and there is a risk of explosion or explosion. Therefore, conventionally, the following countermeasures have been used.

  That is, it is to contain the gas generated by increasing the strength of the container. Alternatively, the generated gas is released to the outside by operating a valve called a safety valve or an explosion-proof valve (see Patent Document 1 or Patent Document 2).

  The gas to be released varies depending on the components of the electrolyte, but when an overvoltage is applied, the main component is the evaporated gas, carbon monoxide, carbon dioxide, etc. of the electrolyte inside the electricity storage device, including fluorine-based gases. Sometimes. Furthermore, when the internal temperature of the electricity storage device rises, thermal decomposition proceeds and flammable gas such as methane is generated.

  Furthermore, opening of a valve called a safety valve or explosion-proof valve of the electricity storage device may cause not only the gas but also the electrolyte itself to be ejected.

JP 2004-190802 A Japanese Patent Laid-Open No. 10-241652

  When the electrolyte of the electricity storage device is decomposed and gas is generated, explosion and rupture of the electricity storage device, prevention of external release of gas and electrolyte, and reduction of shape change of the electricity storage device and safe stop With the goal.

  A container (hereinafter referred to as “depressurized container”) having a reduced pressure is connected to the electricity storage device through a valve, and an adsorbent is installed in the decompressed container. Thus, when the electrolyte in the electricity storage device expands and jumps out or is decomposed due to high temperature or overcharge, the generated gas or the leaked electrolyte is sucked or adsorbed. It is possible to suppress further reaction by sucking or adsorbing the electrolytic solution that has popped out or the generated gas.

  In addition, a detector that can detect gas generated from the electricity storage device and leaked electrolyte is installed in the decompression vessel. And when the detector detects gas and electrolyte solution, this electrical storage device and the object which an electrical storage device supplies electric power will be interrupted | blocked.

  The power storage system includes at least one power storage device including a positive electrode, a negative electrode, and an electrolytic solution, and the inside thereof is decompressed, and is connected to the power storage device via a valve to generate a gas generated from the power storage device or the electrolytic solution. It has a decompression container which absorbs, and an adsorbent which is installed in the decompression container and adsorbs the gas or the electrolytic solution.

  In addition, the power storage system includes at least one power storage device including a positive electrode, a negative electrode, and an electrolytic solution, and the inside is decompressed, and is connected to the power storage device via a valve, and the gas generated from the power storage device or the electrolysis A vacuum container that absorbs liquid; an adsorbent that is installed in the vacuum container and that adsorbs the gas or the electrolyte; a sensor that is provided in the vacuum container and detects the gas or the electrolyte; It has a switch element that receives the signal that the sensor has detected the gas or the electrolytic solution at a specific concentration or more and shuts off the power storage device and a target to which the power storage device supplies power.

  The power storage device is characterized in that it stores electric power again by being charged after being discharged once. Specifically, an electric double layer capacitor, a lithium ion battery, a hybrid capacitor, and the like.

  The valve is a reversely supported valve.

  When the electrolyte of the electricity storage device is decomposed and gas is generated, it is possible to prevent explosion and rupture of the electricity storage device, prevent external release of gas and electrolyte, and reduce the shape change of the electricity storage device. .

1 is a schematic diagram of a power storage system. 1 is a schematic diagram of a power storage system. The perspective view and sectional drawing of an electrical storage device. Perspective view of electricity storage device The perspective view of an electrical storage device, and sectional drawing of a spring.

  Hereinafter, embodiments of the invention disclosed in this specification will be described with reference to the drawings. However, the invention disclosed in this specification can be implemented in many different modes, and various changes can be made in form and details without departing from the spirit and scope of the invention disclosed in this specification. It will be readily understood by those skilled in the art. Therefore, the present invention is not construed as being limited to the description of this embodiment mode. Note that in the drawings described below, the same portions or portions having similar functions are denoted by the same reference numerals, and repetitive description thereof is omitted.

[Embodiment 1]
1A to 1E, FIG. 2, FIG. 3A to FIG. 3B, FIG. 4A to FIG. 4C, and FIG. Description will be made with reference to FIG.

  The power storage system illustrated in FIG. 1A includes a power storage device 101, a decompression container 102, an adsorbent 103, an electrode 104, a detector 105, and a valve 106. The power storage device 101 and the decompression container 102 are connected via a valve 106. The valve 106 may be a reverse valve. When the valve 106 is a reversely supported valve, even if the power storage system is arranged upside down, there is no possibility of leakage of the electrolyte solution 137, so that the ease of handling can be improved. Note that not only one power storage device 101 but also a plurality of power storage devices 101 may be connected. When a plurality of power storage devices 101 are provided, they may be connected in series or in parallel.

  The power storage device 101 is a device that can store electric power again by being charged after being discharged once. Specifically, a hybrid capacitor including a lithium ion battery and a lithium ion capacitor, an electric double layer capacitor, and the like are included.

  The structure of the power storage device 101 is illustrated in FIGS. The power storage device 101 is disposed between a housing 131, a positive electrode 138 including a positive electrode current collector 132 and a positive electrode active material 133, a negative electrode 139 including a negative electrode current collector 134 and a negative electrode active material 135, a positive electrode 138 and a negative electrode 139. A separator 136, an electrolytic solution 137, an electrode 141 a electrically connected to the positive electrode 138, and an electrode 141 b electrically connected to the negative electrode 139 are included. The power storage device 101 may have a structure in which a plurality of positive electrodes, separators, negative electrodes, separators, positive electrodes, separators, and negative electrodes are stacked in this order. Note that a housing for protecting the housing 131 may be provided on the outer side of the housing 131.

  Examples of the positive electrode current collector 132, the positive electrode active material 133, the negative electrode current collector 134, the negative electrode active material 135, the separator 136, and the electrolyte solution 137 are shown below. Note that each of the positive electrode current collector 132, the positive electrode active material 133, the negative electrode current collector 134, the negative electrode active material 135, the separator 136, and the electrolyte solution 137 is not limited to the following, and is necessary. Other materials may be used.

  As the positive electrode current collector 132, a simple substance or a compound such as aluminum (Al) or titanium (Ti) may be used.

As the positive electrode active material 133, activated carbon or _the chemical formula _Li x _M y _{O 2} of LiCoO 2, LiNiO _2, etc. (where, M represents Co, Ni, Mn, V, or the Fe, x is 0.2 ≦ x ≦ 2.5, y may be in the range of 0.8 ≦ y ≦ 1.25).

  The negative electrode current collector 134 may be a simple substance or a compound such as copper (Cu), aluminum (Al), nickel (Ni), or titanium (Ti).

  As the negative electrode active material 135, a lithium ion carrier such as a carbon material, a silicon material, or a silicon alloy material capable of occluding and releasing cations such as lithium ions may be used as the negative electrode active material 135. As such a carbon material, a carbon material such as powdered or fibrous graphite may be used.

  In the case where a silicon material is used for the negative electrode active material 135, a film obtained by forming microcrystalline silicon (microcrystal silicon) and removing amorphous silicon present in the microcrystalline silicon by etching may be used. When the amorphous silicon present in the microcrystalline silicon is removed, the surface area of the remaining microcrystalline silicon is increased.

Alternatively, lithium titanate (Li ₄ Ti ₅ O ₁₂ ) may be used as the negative electrode active material 135. Further, as the negative electrode active material 135, an alloy containing tin (Sn) may be used.

  As the separator 136, paper, nonwoven fabric, glass fiber, or synthetic fiber such as nylon (polyamide), vinylon (also referred to as vinylon) (polyvinyl alcohol fiber), polyester, acrylic, polyolefin, polyurethane, or the like may be used. However, it is necessary to select a material that does not dissolve in the electrolyte solution 137 described later.

  More specifically, examples of the material for the separator 136 include, for example, fluoropolymers, polyethers such as polyethylene oxide and polypropylene oxide, polyolefins such as polyethylene and polypropylene, polyacrylonitrile, polyvinylidene chloride, polymethyl methacrylate, polymethyl acrylate, and polyvinyl. One type selected from alcohol, polymethacrylonitrile, polyvinyl acetate, polyvinyl pyrrolidone, polyethyleneimine, polybutadiene, polystyrene, polyisoprene, polyurethane polymers and derivatives thereof, cellulose, paper, non-woven fabric, or two or more types. You may use it combining.

The electrolytic solution 137 contains a cation such as a proton or lithium ion, and the cation is responsible for electrical conduction. The electrolytic solution 137 includes a solvent and a salt that dissolves in the solvent. As a cation, for example, when lithium ion is used, a lithium salt can be used as a salt. Examples of the lithium salt include LiPF ₆ (lithium hexafluorophosphate), LiClO ₄ , LiBF ₄ , LiPF ₆ , LiAlCl ₄ , LiSbF ₆ , LiSCN, LiCl, LiCF ₃ SO ₃ , LiCF ₃ CO ₂ , Li (CF _{3 SO 2) 2, LiAsF 6,} LiN (CF 3 SO 2) 2, LiB 10 Cl 10, LiN (C 2 F 5 SO 2), LiPF 3 (CF 3) 3, LiPF 3 (C 2 F 5) 3, LiFePO _{4 and the} like can be mentioned, and the electrolyte solution 137 using these can be used alone or in combination of two or more.

  Examples of the solvent of the electrolytic solution 137 include cyclic carbonates such as ethylene carbonate (hereinafter abbreviated as EC), propylene carbonate (PC), butylene carbonate (BC), and vinylene carbonate (VC), dimethyl carbonate (DMC), Acyclic carbonates such as diethyl carbonate (DEC), ethyl methyl carbonate (hereinafter abbreviated as EMC), methyl propyl carbonate (MPC), methyl isobutyl carbonate (MIPC), and dipropyl carbonate (DPC), methyl formate, methyl acetate Aliphatic carboxylic acid esters such as methyl propionate and ethyl propionate, γ-lactones such as γ-butyrolactone, 1,2-dimethoxyethane (DME), 1,2-diethoxyethane (DEE) ), And acyclic ethers such as ethoxymethoxyethane (EME), cyclic ethers such as tetrahydrofuran and 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, trimethyl phosphate, triethyl phosphate, and trioctyl phosphate And alkyl fluoride esters thereof and fluorides thereof, and one or more of these may be used in combination.

  Further, an ionic liquid may be used as the electrolytic solution 137. As the ionic liquid, a pyridine-based ionic liquid, an alicyclic amine-based ionic liquid, an aliphatic amine-based ionic liquid, or the like may be used.

  The decompression vessel 102 may be made of vinyl chloride resin or heat-resistant polyethylene having excellent chemical resistance, heat resistance, and vacuum holding characteristics. Alternatively, a metal such as aluminum, an alloy such as stainless steel, or a metal or alloy coated with an anticorrosive coating may be used.

  The arrangement of the power storage device 101, the decompression container 102, and the valve 106 will be described with reference to FIGS.

  In FIG. 4A, the valve 106 is installed in the housing 131 of the power storage device 101 and is connected to the decompression vessel 102 by a pipe 143. The decompression container 102 may be installed in the vicinity of one surface of the housing 131, and the decompression container 102 may be in contact with the housing 131 or may be separated from the housing 131.

  In FIG. 4B, the housing 131 and the decompression container 102 of the power storage device 101 are arranged adjacent to each other. The valve 106 is disposed so as to directly connect the housing 131 of the electricity storage device 101 and the decompression container 102. An opening may be provided in each of the housing 131 and the decompression container 102, and the valve 106 may be provided in the opening.

  In FIG. 4C, the housing 131 of the power storage device 101 is disposed so as to be covered with the decompression container 102. That is, the electricity storage device 101 is installed inside the decompression vessel 102. The valve 106 is disposed so as to directly connect the housing 131 of the electricity storage device 101 and the decompression container 102. An opening may be provided in each of the housing 131 and the decompression container 102, and the valve 106 may be provided in the opening.

  The inside of the decompression vessel 102 is kept in a negative pressure (decompression) state by decompressing in advance with a vacuum device or the like.

  A tube connecting the power storage device 101 and the decompression vessel 102 may be made of vinyl chloride resin, heat-resistant polyethylene, or the like having excellent chemical resistance, heat resistance, and vacuum holding characteristics. Alternatively, a metal such as aluminum, an alloy such as stainless steel, or a metal or alloy coated with an anticorrosive coating may be used.

When a reversely supported valve is used as the valve 106, the reversely supported valve may be a reversible valve or a release valve, and an electromagnetic valve may be used. These reverse valves are actuated when gas is generated and a certain level of force is applied. Compressive strength may have 1~60Kg / cm ^2, preferably about 2~40Kg / cm ^2, further preferably, it is about 2~30Kg / cm ^2.

  An example of the structure of the valve 106 is shown in FIGS. 5 (B) and 5 (C).

  In FIG. 5 (B), the valve 106 is arranged so as to hold the cylindrical body 211 with the upper part closed vertically and the ball 212 accommodated therein and the upper part of the ball 212 at one end and the other end at the other end. And a spring 213 fixed to the closed upper portion of the main body 211. That is, the spring 213 urges the ball 212 downward.

  In addition, an opening 214 connected to the opening 201 of the electricity storage device 101 is provided below the main body 211 of the valve 106. The ball 212 is configured to be pressed by a spring 213 and forcibly close the opening 214.

  Further, a discharge port 215 is provided at an intermediate portion of the main body 211 located between the ball 212 and the closed upper portion of the main body 211 in a state where the ball 212 blocks the opening 214. In FIG. 5B, four discharge ports 215 are provided in the main body 211 at an equal angular distribution (only two are shown). However, if the discharge ports 215 have a sufficient opening area for gas or electrolyte discharge. The number of the discharge ports 215 may be one.

  A pressure setting element 216 is provided at the center of the closed upper portion of the main body 211. The pressure setting element 216 has a female screw 216b installed on the closed upper portion and a male screw 216a that is screwed to the female screw 216b. The amount of compression of the spring 213 can be adjusted by rotating the male screw 216a. By adjusting the compression amount of the spring 213, the opening pressure of the gas or the electrolyte can be set as appropriate.

  In such a configuration, for example, when the gas pressure of the electricity storage device 101 rises, gas enters from the electricity storage device 101 into the inside of the main body 211 of the valve 106 and below the ball 212 through the opening 201 and the opening 214, When the pressure below 212 rises to a predetermined value, the pressure value set by the pressure setting element 216, the spring 213 is compressed and the ball 212 is pushed up. Since the opening 14 is thus opened, the gas is released, and it is possible to prevent the gas pressure from rising further.

  FIG. 5C shows the structure of the valve 106 having a structure different from that in FIG.

  In FIG. 5C, the valve 106 includes a cylindrical main body 221 that is vertically arranged and has an open upper portion, and a jig 223 that seals the opened upper portion with an insulator 225 interposed therebetween. Further, an opening 224 connected to the opening 201 of the electricity storage device 101 is provided in the lower portion of the main body 221 of the valve 106.

  In the structure illustrated in FIG. 5B, for example, when the gas pressure of the power storage device 101 is increased, the pressure is increased by receiving the pressure and detaching the jig 223 alone or the jig 223 and the insulator 225. That can be suppressed.

  As the adsorbent 103, for example, porous activated carbon can be used as a gas adsorbent. In addition, chemical fibers, natural fibers, and the like having excellent adsorptive power can be used as the adsorbent for the electrolytic solution.

  The gas and / or electrolyte solution adsorbed by the adsorbent 103 may be detected using a detection agent. The detection agent may be an organic gas or liquid detection agent suitable for each electrolytic solution. Moreover, as a detecting agent for detecting a gas generated when the electrolytic solution is decomposed, a detecting agent such as carbon monoxide, carbon dioxide, methane, ethane, or propane may be used. For example, in order to detect an electrolytic solution used in a lithium ion battery or a decomposition product of the electrolytic solution, a detection agent that detects an acid such as hydrofluoric acid may be used.

  The detector 105 may further detect the gas and / or electrolyte detected by the detection agent.

  When the electrolytic solution 137 is decomposed and gas 108 is generated (see FIG. 1B), thereby increasing the pressure in the power storage device 101, the valve 106 is opened (see FIG. 1C). Since the decompression container 102 is maintained at a negative pressure, the gas 108 moves to the decompression container 102 (see FIG. 1D). Further, the electrolytic solution 137 also flows into the decompression vessel 102 and accumulates in the decompression vessel 102. The decompression vessel 102 contains an adsorbent 103 and sucks and adsorbs the gas 108 and the electrolyte solution 137.

  The valve 106 or the adsorbent 103 is interlocked with the detector 105 and outputs a signal 107 when the valve 106 is opened or when the adsorbent 103 sucks and adsorbs the gas 108 or the electrolyte 137 (FIG. 1 ( E)). The switch element is actuated by the signal 107, shuts off the power storage device 101 and the external electrode, and makes it unusable. The detector 105 may use a pressure sensor or a concentration meter, and may be installed inside the decompression vessel 102 or may be installed outside. The detector 105 may be electrically connected to the power storage device 101 or may be connected by piping depending on the type of the detector 105. In addition, the leaked electrolyte solution 137 is separated from the electricity storage device 101 to prevent a subsequent temperature increase and gas generation.

  FIG. 5A illustrates an example of a positional relationship between the power storage device 101, the decompression container 102, and the detector 105.

  5A, the same arrangement as that shown in FIG. 4B is used for the storage device 101, the decompression container 102, and the valve 106.

  In FIG. 5A, the detector 105 is disposed in contact with one surface of the decompression container 102, but may be disposed separately. FIG. 5A illustrates an example in which the detector 105 is connected to the power storage device 101 through a tube 145.

  When gas is generated in the power storage device 101, the generated gas 108 moves to the decompression container 102, and further moves to the detector 105 through the pipe 145. The type of the gas 108 can be specified by the detector 105.

  Further, the electrolyte solution 137 is sucked into the decompression container 102, whereby the energy inside the electricity storage device 101 is reduced, and the temperature rise and further gas generation are prevented.

  A thermal runaway model of a lithium ion battery has been proposed in the order of reaction between the negative electrode and the electrolytic solution, thermal decomposition of the electrolytic solution, reaction between the positive electrode and the electrolytic solution, and thermal decomposition of the negative electrode. Therefore, the recovery of the electrolytic solution is effective for preventing heat generation.

  By making the electricity storage device 101 unusable, further decomposition of the electrolyte solution 137 can be prevented.

  FIG. 2 shows a power storage system having a structure different from those shown in FIGS. The power storage system illustrated in FIG. 2 includes a power storage device 111, a decompression vessel 112, an adsorbent 113, a valve 114, and a detector 115, and is connected to the power unit 116 to supply power. In the decompression vessel 112, an adsorbent 113 and a detector (sensor) 115 for detecting an electrolytic solution or a decomposition product of the electrolytic solution are installed. The decompression vessel 112 is maintained at a negative pressure (decompression). The detector 115 may be electrically connected to the power storage device 111 or may be connected by piping depending on the type of the detector 115.

  One or a plurality of power storage devices 111 may be provided. When a plurality of power storage devices 111 are provided, they may be connected in series or in parallel.

  The power storage system shown in FIG. 2 is similar to the power storage system shown in FIGS. 1A to 1E, when the electrolyte solution is decomposed due to high temperature or overcharge in the power storage device 111 and gas is generated, The valve 114 is opened and the gas reaches the decompression vessel 112 through the valve 114.

  The adsorbent 113 installed in the decompression vessel 112 sucks or adsorbs the generated gas. Further, even when the electrolytic solution is ejected, the electrolytic solution ejected by the adsorbent 113 can be sucked or adsorbed.

  When the adsorbent 113 sucks or adsorbs the electrolytic solution or gas, a signal 117 is output by the detector 115 interlocked with the decompression vessel 112. The detection signal 117 cuts off the connection between the power storage device 111 and the target (power unit 116) to which the power storage device supplies power. In order to cut off this connection, a switch such as a fuse may be used.

  Examples of the power unit 116 include an automobile engine. Even if the power storage device 111 is destroyed, the automobile can be stopped by cutting off the connection between the power storage device 111 and the engine.

DESCRIPTION OF SYMBOLS 101 Power storage device 102 Pressure-reducing container 103 Adsorbent 104 Electrode 105 Detector 106 Valve 107 Signal 108 Gas 111 Power storage device 112 Pressure-reducing container 113 Adsorbent 114 Valve 115 Detector 116 Power unit 117 Signal 131 Case 132 Positive electrode current collector 133 Positive electrode active Material 134 Negative electrode current collector 135 Negative electrode active material 136 Separator 137 Electrolyte 138 Positive electrode 139 Negative electrode 141a Electrode 141b Electrode 143 Tube 145 Tube 201 Opening 211 Main body 212 Ball 213 Spring 214 Opening 215 Release port 216 Pressure setting element 216a Male screw 216b Female screw 221 Insulation zone 223 Jig 224 Opening 225 Insulator

Claims (1)

At least one power storage device comprising a positive electrode, a negative electrode, an electrolyte solution;
The inside is depressurized, connected to the electricity storage device via a valve, and absorbs the gas generated from the electricity storage device or the electrolyte, and
An adsorbent installed in the container and adsorbing the gas or the electrolyte;
A sensor provided in the container for detecting the gas or the electrolyte;
In response to a signal that the sensor has detected the gas or the electrolytic solution at a specific concentration or more, the sensor device has a switch element that shuts off the power storage device and a target to which the power storage device supplies power,
The valve is a reverse valve;
The electricity storage system , wherein the valve has a pressure resistance of ² to 30 kg / cm ² .

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