JP2013168349A - Secondary battery and secondary battery module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a secondary battery improved in safety in the case of leakage of an electrolyte.SOLUTION: A secondary battery 100 comprises: an electrode group 40 including a cathode 10 and an anode 20; an exterior container 60 which includes a storage container 70 storing the electrode group 40, a sealing body 80 sealing an opening 73 of the storage container 70 over the whole periphery, a recess formed in an outer top surface 81a of the sealing body 80, and a safety valve 85 provided in the recess; and an electrolyte directly filled in the exterior container 60.

Description

  The present invention relates to a secondary battery and a secondary battery module obtained by modularizing a plurality of secondary batteries.

  In recent years, along with the rapid miniaturization and multi-functionalization of consumer mobile phones, portable electronic devices, personal digital assistants, etc., the battery that is the power source is small and light, high energy density, and can be repeatedly charged and discharged for a long time. There is a demand for a secondary battery that satisfies the following conditions. As a secondary battery that satisfies these requirements, a lithium ion secondary battery having a higher energy density than other secondary batteries is considered most promising. Various researches and developments have been conducted to develop better lithium ion secondary batteries.

In addition, in consideration of environmental problems such as global warming, lithium ion secondary batteries have been used in power storage systems used in solar power generation systems, wind power generation systems, and the like. In addition, as a measure against CO ₂ reduction and energy problems, there is an increasing expectation for the spread of hybrid vehicles (HEVs) and electric vehicles (EVs) with low fuel consumption and low exhaust gas. Development and commercialization of lithium-ion secondary batteries targeting the above are also in progress.

  Thus, the demand for lithium ion secondary batteries not only for portable devices but also for large-scale power is increasing. When using lithium ion secondary batteries for power or power storage systems, it is necessary to increase the capacity in order to enable long-term discharge. Usually, assembled batteries with a plurality of unit cells connected are used. . From the viewpoint of handling and installation space, the assembled battery is often modularized by arranging or stacking single cells.

  Various safety measures have been proposed for such secondary batteries and modularized secondary battery modules.

  For example, in Patent Document 1, at least one power storage device including a positive electrode, a negative electrode, and an electrolyte solution, and the inside is decompressed, connected to the power storage device via a valve, and a gas generated from the power storage device or A vacuum container that absorbs the electrolyte; and an adsorbent that is installed in the vacuum container and that adsorbs the gas or the electrolyte; and detects the gas or the electrolyte in the vacuum container There is disclosed a power storage system that shuts off the power storage device and a target to which the power storage device supplies power in response to a signal that the sensor detects the gas or the electrolyte at a specific concentration or higher. ing.

  Patent Document 2 discloses that in a battery module composed of a plurality of cells each having an explosion-proof valve, an electrolyte gas released by any one of the plurality of explosion-proof valves is released to the outside of the battery module. There is disclosed a battery module comprising: a discharge portion that forms a space; and a sensor that detects an electrolyte gas flowing into the space formed by the discharge portion.

  In Patent Document 3, an exhaust duct, a fire extinguishing gas pipe, and a water or fire extinguishing agent pipe are connected to each shelf of a battery aging device, and an atmosphere sensor is provided in a branch pipe of each shelf. It is disclosed to detect a liquid or gaseous leak of an organic electrolyte from a battery or the like.

  Further, Patent Document 4 discloses that a gas sensor is provided in the vicinity of an assembled battery device formed by connecting batteries containing an organic solvent in an electrolytic solution in series and parallel.

JP 2011-60554 A JP 2009-43592 A JP 2000-188135 A Japanese Patent Laid-Open No. 10-12285

  Usually, a lithium ion secondary battery has a structure such as a safety valve for releasing the internal pressure of the battery when excessive heat is generated due to deterioration or overcharge as a safety measure. However, no countermeasure is shown when the electrolyte solution leaks, and the leaked electrolyte solution may immediately flow down from the secondary battery and further flow out of the module. Moreover, if the leaked electrolyte solution volatilizes, there is a risk of ignition by the electrical system in the module.

  An object of this invention is to provide the secondary battery which improved the safety | security when electrolyte solution leaks. Another object of the present invention is to provide a secondary battery module obtained by modularizing the secondary battery.

  To achieve the above object, the present invention provides an electrode group including a positive electrode and a negative electrode, a storage container that stores the electrode group, a sealing body that seals the opening of the storage container over the entire circumference, and the sealing A secondary battery is provided that includes an exterior container including a recess formed on the outer top surface of the body, a safety valve provided in the recess, and an electrolyte directly filled in the exterior container.

  According to this configuration, when the internal pressure of the battery increases, the safety valve opens, and when the electrolyte leaks, the electrolyte accumulates in the recess.

  In the above secondary battery, it is preferable that the recess is formed to face the entire opening of the storage container. By increasing the volume of the recess, more leaked electrolyte can be stored.

  Moreover, this invention makes it a secondary battery module provided with the assembled battery which laminated | stacked said secondary battery, and the housing | casing which accommodates this assembled battery.

  Said secondary battery module WHEREIN: It is preferable that the said assembled battery has a space above the said recessed part. With this space, a space for opening the safety valve and a space for storing the leaked electrolyte can be secured. Moreover, the cooling effect of a secondary battery is also acquired.

  For example, the space is formed by arranging the secondary batteries on a plurality of shelves formed in the housing.

  The secondary battery module preferably includes a sensor that detects the gas of the electrolytic solution and a breaker that shuts off the power system when the sensor detects the gas. Thereby, generation | occurrence | production of the spark etc. which become a fire type is eliminated, it can prevent that an electrolyte solution ignites, and can improve safety | security.

  The secondary battery module preferably includes a sensor that detects the gas of the electrolytic solution and a notification unit that notifies the sensor when the sensor detects the gas. Thereby, when there is a warning, the user can safely stop the electric device connected to the secondary battery module by a normal stopping method.

  In the above secondary battery module, it is preferable that the sensor is provided below the assembled battery from the viewpoint of efficiently and quickly detecting the descending electrolyte gas.

  The secondary battery module may further include a sensor attachment member that is provided across the opposing inner side walls of the casing, to which the sensor is attached, and having a hole through which the electrolyte gas can pass.

  In the above secondary battery module, it is preferable that a tray for storing the leaked electrolyte is provided below the assembled battery. As a result, even if the electrolyte overflows from the concave portion of any secondary battery, it can be prevented from finally collecting in the tray and flowing out of the casing.

  According to the present invention, since the electrolyte leaked from the safety valve is stored in the recess of the top surface of the secondary battery, it is possible to prevent the leaked electrolyte from immediately flowing down from the secondary battery, thereby improving safety. . Moreover, the safety | security at the time of electrolyte solution leakage can also be improved by providing a sensor and a saucer in a secondary battery module.

It is a disassembled perspective view of the lithium ion secondary battery of 1st Embodiment of this invention. It is a disassembled perspective view of the lithium ion secondary battery of 1st Embodiment of this invention. 1 is an overall perspective view of a lithium ion secondary battery according to a first embodiment of the present invention. It is a top view of the lithium ion secondary battery of 1st Embodiment of this invention. It is the perspective view which showed the structure of the electrode group of the lithium ion secondary battery of 1st Embodiment of this invention. It is the perspective view which showed the structure of the positive electrode of the lithium ion secondary battery of 1st Embodiment of this invention. It is the top view which showed the structure of the positive electrode of the lithium ion secondary battery of 1st Embodiment of this invention. It is the perspective view which showed the structure of the negative electrode of the lithium ion secondary battery of 1st Embodiment of this invention. It is the top view which showed the structure of the negative electrode of the lithium ion secondary battery of 1st Embodiment of this invention. It is sectional drawing which showed the structure of the electrode group of the lithium ion secondary battery of 1st Embodiment of this invention. It is a perspective view of the armored can of the lithium ion secondary battery of 1st Embodiment of this invention. It is a top view of the armored can of the lithium ion secondary battery of 1st Embodiment of this invention. FIG. 4 is a sectional view taken along line AA in FIG. 3. It is a schematic sectional side view of the secondary battery module of 2nd Embodiment of this invention. It is a schematic sectional side view of the secondary battery module of 3rd Embodiment of this invention. It is a schematic sectional side view of the secondary battery module of 4th Embodiment of this invention. It is a bottom view of the sensor attachment member to which the sensor of 4th Embodiment of this invention was attached.

  In the following embodiments, a case where the present invention is applied to a stacked lithium ion secondary battery which is an example of a secondary battery will be described.

(First embodiment)
1 and 2 are exploded perspective views of the lithium ion secondary battery according to the first embodiment of the present invention. FIG. 3 is an overall perspective view of the lithium ion secondary battery according to the first embodiment of the present invention. FIG. 4 is a top view of the lithium ion secondary battery according to the first embodiment of the present invention. 5-13 is a figure for demonstrating the lithium ion secondary battery of 1st Embodiment of this invention. FIG. 4 shows a state in which the sealing plate 80 originally provided is removed so that the inside of the lithium ion secondary battery can be seen.

  The lithium ion secondary battery 100 of 1st Embodiment has square flat shape (refer FIG. 3), as shown in FIGS. 1-4, and the positive electrode 10 (refer FIG. 1) and the negative electrode 20 (FIG. 1). Electrode group 40 (see FIG. 1 and FIG. 2), and a metal outer container 60 that encloses the electrode group 40 together with a non-aqueous electrolyte. The positive electrode 10 and the negative electrode 20 are examples of the “electrode” in the present invention.

  As shown in FIGS. 1 and 5, the electrode group 40 further includes a separator 30 for suppressing a short circuit between the positive electrode 10 and the negative electrode 20. The positive electrode 10 and the negative electrode 20 are arranged to face each other with the separator 30 in between. The electrode group 40 includes a plurality of positive electrodes 10, negative electrodes 20, and separators 30. The positive electrode 10, the separator 30, and the negative electrode 20 are sequentially stacked to form a stacked structure (laminated body 40 a). . Note that the positive electrodes 10 and the negative electrodes 20 are alternately stacked one by one. The electrode group 40 is configured such that one positive electrode 10 is located between two adjacent negative electrodes 20. Further, a separator 30 is disposed on the outermost side of the electrode group 40.

  The electrode group 40 includes, for example, 24 positive electrodes 10, 25 negative electrodes 20, and 50 separators 30. The positive electrodes 10 and the negative electrodes 20 are alternately stacked with the separators 30 interposed therebetween.

  As shown in FIGS. 6 and 7, the positive electrode 10 constituting the electrode group 40 has a configuration in which the positive electrode active material layer 12 is supported on both surfaces of the positive electrode current collector 11.

  The positive electrode current collector 11 has a function of collecting the positive electrode active material layer 12. The positive electrode current collector 11 is made of, for example, a metal foil such as aluminum, titanium, stainless steel, nickel, iron, or an alloy foil made of these alloys, and has a thickness of about 1 μm to about 500 μm (for example, about 20 μm). It has the thickness of. The positive electrode current collector 11 is preferably an aluminum foil or an aluminum alloy foil, and the thickness is preferably 20 μm or less.

  In addition to the above, the positive electrode current collector 11 may be, for example, an aluminum or copper surface treated with carbon, nickel, titanium, silver or the like for the purpose of improving conductivity and oxidation resistance. For these, the surface can be oxidized. Further, a clad material of copper and aluminum, a clad material of stainless steel and aluminum, or a plating material combining these metals may be used. A current collector in which two or more metal foils are bonded together can also be used. Furthermore, the positive electrode current collector 11 has a film shape, a sheet shape, a net shape, a punched or expanded shape, a lath body, a porous body, a foamed body, a formed body of fiber groups, etc. in addition to the foil shape. There may be.

The positive electrode active material layer 12 includes a positive electrode active material that can occlude and release lithium ions. As a positive electrode active material, the oxide containing lithium is mentioned, for example. Specific examples include LiCoO ₂ , LiFeO ₂ , LiMnO ₂ , LiMn ₂ O ₄ , and compounds in which transition metals in these oxides are partially substituted with other metal elements. Among these, in a normal use, it is preferable to use a material that can utilize 80% or more of the amount of lithium held by the positive electrode for the battery reaction. As a result, the safety of the secondary battery against accidents such as overcharging can be enhanced.

Examples of such a positive electrode active material include a compound having a spinel structure such as LiMn ₂ O ₄ and LiMPO ₄ (M is at least one element selected from Co, Ni, Mn, and Fe). Examples thereof include compounds having an olivine structure. Among these, a positive electrode active material containing at least one of Mn and Fe is preferable from the viewpoint of cost. Furthermore, from the viewpoint of safety and charging voltage, it is preferable to use LiFePO ₄ . In LiFePO ₄ , since all oxygen (O) is bonded to phosphorus (P) by a strong covalent bond, release of oxygen due to a temperature rise hardly occurs. Therefore, it is excellent in safety.

  In addition, the thickness of the positive electrode active material layer 12 is preferably about 20 μm to 2 mm, and more preferably about 50 μm to 1 mm.

  Further, the configuration of the positive electrode active material layer 12 is not particularly limited as long as it includes at least the positive electrode active material. For example, the positive electrode active material layer 12 may contain other materials such as a conductive material, a thickener, and a binder in addition to the positive electrode active material.

  The conductive material is not particularly limited as long as it is an electron conductive material that does not adversely affect the battery performance of the positive electrode 10. For example, carbon black, acetylene black, ketjen black, graphite (natural graphite, artificial graphite), carbon fiber, etc. These carbonaceous materials and conductive metal oxides can be used. Among these, as the conductive material, carbon black and acetylene black are preferable from the viewpoints of electron conductivity and coatability.

  As the thickener, for example, polyethylene glycols, celluloses, polyacrylamides, poly N-vinyl amides, poly N-vinyl pyrrolidones and the like can be used. Among these, as the thickener, celluloses such as polyethylene glycols and carboxymethyl cellulose (CMC) are preferable, and CMC is particularly preferable.

  The binder serves to bind the active material particles and the conductive material particles. For example, a fluorine-based polymer such as polyvinylidene fluoride (PVdF), polyvinylpyridine, polytetrafluoroethylene, or a polyolefin such as polyethylene or polypropylene. Polymers, styrene butadiene rubber, fluoro rubber, etc. can be used.

  Examples of the solvent for dispersing the positive electrode active material, the conductive material, the binder, etc. include N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, methyl ethyl ketone, cyclohexanone, methyl acetate, methyl acrylate, diethyltriamine, N, Organic solvents such as N-dimethylaminopropylamine, ethylene oxide, and tetrahydrofuran, and water can be used.

  The positive electrode 10 described above is obtained by mixing a positive electrode active material, a conductive material, a thickening material, and a binder, and adding a suitable solvent to form a paste-like positive electrode mixture. It is formed by compressing to dry the electrode and increasing the electrode density as necessary.

  Further, as shown in FIG. 7, the positive electrode 10 has a rectangular shape in plan view, and includes four edge portions 14 (two edge portions 14a in the X direction and two edge portions in the Y direction). 14b). In the first embodiment, the positive electrode 10 has a width w1 in the Y direction of about 146 mm, for example, and a length g1 in the X direction of about 208 mm, for example. Further, in the application region (formation region) of the positive electrode active material layer 12, the width w11 in the Y direction is the same as the width w1 of the positive electrode 10, for example, about 146 mm, and the length g11 in the X direction is, for example, It is about 196 mm. For this reason, the positive electrode active material layer 12 formed in the coating region is formed in a rectangular shape when seen in a plan view, and has four edge portions 13 (two edge portions 13a along the X direction, in the Y direction). It has two edges 13b) along.

  The positive electrode 10 has a current collector exposed portion 11a at one end in the X direction where the positive electrode active material layer 12 is not formed and the surface of the positive electrode current collector 11 is exposed. The current collector exposed portion 11a is electrically connected to a current collector lead 5 (see FIG. 4), which will be described later, for taking out current to the outside. The four edge portions 13 in the positive electrode active material layer 12 are the same as those in the positive electrode 10 except for one side (the edge portion 13b on the current collector exposed portion 11a side) of the two edge portions 13b along the Y direction. It coincides with the edge 14.

  As shown in FIGS. 8 and 9, the negative electrode 20 constituting the electrode group 40 has a configuration in which a negative electrode active material layer 22 is supported on both surfaces of a negative electrode current collector 21.

  The negative electrode current collector 21 has a function of collecting the negative electrode active material layer 22. The negative electrode current collector 21 is made of, for example, a metal foil such as copper, nickel, stainless steel, iron, or a nickel plating layer, or an alloy foil made of these alloys, and has a thickness of about 1 μm to about 100 μm (for example, about 16 μm) in thickness. The negative electrode current collector 21 is preferably a metal foil made of copper or stainless steel, and the thickness is preferably 4 μm or more and 20 μm or less.

  Moreover, the negative electrode current collector 21 has a film shape, a sheet shape, a net shape, a punched or expanded shape, a lath body, a porous body, a foamed body, a formed body of fiber groups, etc. in addition to the foil shape. There may be.

  The negative electrode active material layer 22 includes a negative electrode active material that can occlude and release lithium ions. As the negative electrode active material, for example, a material containing lithium or a material capable of occluding and releasing lithium is used. Further, in order to constitute a high energy density battery, it is preferable that the potential for insertion / extraction of lithium is close to the deposition / dissolution potential of metallic lithium. Typical examples thereof include particulate natural graphite or artificial graphite (scale-like, lump-like, fibrous, whisker-like, spherical, pulverized particle-like, etc.).

As the negative electrode active material, artificial graphite obtained by graphitizing mesocarbon microbeads, mesophase pitch powder, isotropic pitch powder, or the like may be used. Further, graphite particles having amorphous carbon attached to the surface can also be used. Furthermore, lithium transition metal oxides, lithium transition metal nitrides, transition metal oxides, silicon oxides, and the like can also be used. As the lithium transition metal oxide, for example, when lithium titanate typified by Li ₄ Ti ₅ O ₁₂ is used, the deterioration of the negative electrode 20 is reduced, so that the battery life can be extended.

  The thickness of the negative electrode active material layer 22 is preferably about 20 μm to 2 mm, and more preferably about 50 μm to 1 mm.

  Further, the configuration of the negative electrode active material layer 22 is not particularly limited as long as it includes at least a negative electrode active material. For example, the negative electrode active material layer 22 may include other materials such as a conductive material, a thickener, and a binder in addition to the negative electrode active material. In addition, what can be used for the positive electrode active material layer 12 can be used for other materials, such as a electrically conductive material, a thickener, and a binder.

  The negative electrode 20 described above is obtained by mixing a negative electrode active material, a conductive material, a thickener and a binder, and adding a suitable solvent to form a paste-like negative electrode mixture. It is formed by compressing to dry the electrode and increasing the electrode density as necessary.

  Further, as shown in FIG. 9, the negative electrode 20 has a rectangular shape in plan view, and includes four edge portions 24 (two edge portions 24a in the X direction and two edge portions in the Y direction). 24b). Further, the negative electrode 20 is formed in a larger planar area than the positive electrode 10 (see FIGS. 7 and 8). In the first embodiment, the negative electrode 20 has a width w2 in the Y direction larger than the width w1 of the positive electrode 10 (see FIG. 7), for example, about 150 mm, and has a length g2 in the X direction. The length of the positive electrode 10 is longer than the length g1 (see FIG. 7), for example, about 210 mm.

  Further, in the application region (formation region) of the negative electrode active material layer 22, the width w21 in the Y direction is the same as the width w2 of the negative electrode 20, for example, about 150 mm, and the length g21 in the X direction is, for example, About 200 mm. For this reason, the negative electrode active material layer 22 formed in the coating region is formed in a rectangular shape in plan view, and has four edge portions 23 (two edge portions 23a along the X direction, in the Y direction). It has two edges 23b) along.

  In addition, the negative electrode 20 has a current collector exposed portion 21 a in which the surface of the negative electrode current collector 21 is exposed without forming the negative electrode active material layer 22 at one end in the Y direction, like the positive electrode 10. . The current collector exposed portion 21a is electrically connected to a current collector lead 5 (see FIG. 4), which will be described later, for extracting a current to the outside. The four edge portions 23 in the negative electrode active material layer 22 are in the positive electrode 10 except for one side (the edge portion 23b on the current collector exposed portion 21a side) of the two edge portions 23b along the Y direction. It coincides with the edge 14.

  The separator 30 constituting the electrode group 40 is preferably a separator having sufficient strength and capable of holding a large amount of electrolyte solution. From such a viewpoint, a microporous film or a nonwoven fabric containing polyethylene, polypropylene, or ethylene-propylene copolymer is used. Is preferred.

  In addition to the above, the separator 30 may be, for example, polyvinylidene fluoride, polyvinylidene chloride, polyacrylonitrile, polyacrylamide, polytetrafluoroethylene, polysulfone, polyethersulfone, polycarbonate, polyamide, polyimide, polyether (polyethylene oxide, polypropylene). Oxide), cellulose (carboxymethylcellulose, hydroxypropylcellulose), poly (meth) acrylic acid, microporous film made of a polymer such as poly (meth) acrylate, and the like can be used. Furthermore, a multilayer film obtained by superimposing these microporous films can also be used.

  The thickness of the separator 30 is preferably 5 μm to 100 μm, and more preferably 10 μm to 30 μm. Further, the porosity of the separator 30 is preferably 30% to 90%, and more preferably 40% to 80%. If the thickness of the separator 30 is smaller than 5 μm, the mechanical strength of the separator 30 is insufficient, causing an internal short circuit of the battery. On the other hand, when the thickness of the separator 30 is larger than 100 μm, the distance between the positive electrode and the negative electrode is increased, and the internal resistance of the battery is increased. On the other hand, when the porosity is lower than 30%, the content of the non-aqueous electrolyte decreases and the internal resistance of the battery increases. On the other hand, if the porosity is higher than 90%, the positive electrode 10 and the negative electrode 20 are brought into physical contact, causing an internal short circuit of the battery. Further, the separator 30 may be used by stacking a plurality of separators in consideration of mechanical strength, non-aqueous electrolyte content, battery internal resistance, ease of internal short circuit of the battery, etc., depending on the thickness and porosity. Is possible.

  Further, as shown in FIG. 10, the separator 30 has a shape larger than the application region (formation region N) of the positive electrode active material layer 12 and the application region (formation region M) of the negative electrode active material layer 22. . Specifically, as shown in FIGS. 5 and 10, for example, the separator 30 has a length in the vertical direction (a length corresponding to the X direction) of about 154 mm and a length in the horizontal direction (Y direction). Is formed in a rectangular shape having a length in the direction corresponding to the length of about 206 mm.

  The positive electrode 10 and the negative electrode 20 described above are arranged such that the current collector exposed portion 11a of the positive electrode 10 and the current collector exposed portion 21a of the negative electrode 20 are located on opposite sides, and a separator 30 is interposed between the positive and negative electrodes. Are stacked.

  The nonaqueous electrolytic solution enclosed with the electrode group 40 in the outer container 60 is not particularly limited, but examples of the solvent include ethylene carbonate (EC), propylene carbonate, butylene carbonate, diethyl carbonate (DEC), Esters such as dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), and γ-butyrolactone, and ethers such as tetrahydrofuran, 2-methyltetrahydrofuran, dioxane, dioxolane, diethyl ether, dimethoxyethane, diethoxyethane, methoxyethoxyethane , Polar solvents such as dimethyl sulfoxide, sulfolane, methyl sulfolane, acetonitrile, methyl formate, and methyl acetate can be used. These solvents may be used alone, or two or more kinds may be mixed and used as a mixed solvent.

The nonaqueous electrolytic solution may contain an electrolyte supporting salt. Examples of the electrolyte supporting salt include LiClO ₄ , LiBF ₄ (lithium borofluoride), LiPF ₆ (lithium hexafluorophosphate), LiCF ₃ SO ₃ (lithium trifluoromethanesulfonate), LiF (lithium fluoride), LiCl. Examples thereof include lithium salts such as (lithium chloride), LiBr (lithium bromide), LiI (lithium iodide), LiAlCl ₄ (lithium tetrachloride aluminate) and the like. These may be used singly or in combination of two or more.

  The concentration of the electrolyte supporting salt is not particularly limited, but is preferably 0.5 mol / L to 2.5 mol / L, and more preferably 1.0 mol / L to 2.2 mol / L. When the concentration of the electrolyte support salt is less than 0.5 mol / L, the carrier concentration for carrying charges in the non-aqueous electrolyte is lowered, and the resistance of the non-aqueous electrolyte may be increased. Further, when the concentration of the electrolyte supporting salt is higher than 2.5 mol / L, the dissociation degree of the salt itself is lowered, and there is a possibility that the carrier concentration in the non-aqueous electrolyte does not increase.

  The exterior container 60 that encloses the electrode group 40 is a large flat rectangular container. As shown in FIGS. 1 to 3, an exterior can 70 that houses the electrode group 40 and the like, and a sealing plate that seals the exterior can 70. 80. Further, the outer can 70 in which the electrode group 40 is accommodated is sealed with a sealing plate 80 (preferably a double-tightened seal). The outer can 70 is an example of the “storage container” in the present invention, and the sealing plate 80 is an example of the “sealing body” in the present invention.

  The outer can 70 is formed by, for example, drawing a metal plate, and has a bottom surface 71 and a side wall 72. As shown in FIGS. 11 and 12, an opening 73 for inserting the electrode group 40 is provided at one end of the outer can 70 (the side opposite to the bottom surface portion 71). The outer can 70 is formed in a rectangular can, and the area of the substantially rectangular opening 73 is larger than the area of the substantially rectangular bottom surface 71. That is, the corners 72a at the four corners of the side wall 72 are linearly expanded from the bottom surface 71 side to the opening 73 side.

  The inner diameter of the outer can 70 is such that the electrode group 40 can be accommodated so that the electrode surface faces the bottom surface 71. Specifically, in the outer can 70, for example, the length of the bottom surface portion 71 in the vertical direction (the length L in the Y direction in FIG. 12) is formed to be about 164 mm. The length (length W in the X direction in FIG. 12) is about 228 mm. The depth of the outer can 70 is, for example, about 20 mm.

  Moreover, in the said exterior can 70, the electrode terminals 74 and 74 are each formed in each side wall part 72 and 72 parallel to a Y direction. Furthermore, a container folding portion 75 for performing a winding sealing (preferably a double winding sealing) is provided at the periphery of the opening 73 of the outer can 70.

  The sealing plate 80 is formed, for example, by pressing a metal plate. As shown in FIG. 2, the sealing plate 80 includes a panel portion 81 having a substantially flat rectangular shape that closes the opening 73 of the outer can 70, a chuck wall portion 82 that continues to the outer peripheral end of the panel portion 81 and extends upward, and a chuck And a folded portion 83 connected to the outer peripheral end of the wall portion 82. The panel portion 81 and the chuck wall portion 82 form a recess. In other words, it can be said that the recess is formed on the outer top surface 81 a of the sealing plate 80. The depth of the recess (the height of the chuck wall portion 82) is preferably about 1 to 20 mm. The size and position of the concave portion are not limited as long as the concave portion is formed on the outer top surface 81a of the sealing plate 80. However, the concave portion preferably has a large volume, and as shown in FIG. It is preferable that they are formed to face each other. Thereby, even if a recessed part is shallow in order to make the exterior can 70 thin, the volume of a recessed part can be enlarged.

  The fixing of the sealing plate 80 and the outer can 70 is not limited to the winding sealing as long as the sealing plate 80 can be sealed with pressure resistance, and may be fixed by welding with a laser or the like.

  Further, as shown in FIGS. 2 and 3, the panel portion 81 is formed with a liquid injection hole 84 for injecting a non-aqueous electrolyte on one side in the X direction. The liquid injection hole 84 is formed in a size of φ2 mm, for example.

  Further, the panel portion 81 is provided with a safety valve 85 that is opened when the battery internal pressure exceeds a specified pressure. The rise in battery internal pressure is caused by excessive heat generation due to deterioration, overcharge, or the like. The safety valve 85 is, for example, a φ8 mm through hole sealed from the outside with a cap, and is opened when the cap is removed due to an increase in battery internal pressure. The safety valve 85 may be provided anywhere in the recess. The safety valve 85 and the panel portion 81 can be welded with a laser or the like so as to cover the through hole.

  Thus, by providing the safety valve 85 in the recess of the sealing plate 80, the safety valve 85 opens when the battery internal pressure increases, and the electrolyte accumulates in the recess when the electrolyte leaks. Therefore, it is possible to prevent the leaked electrolyte from immediately flowing down from the secondary battery. Further, by increasing the volume of the concave portion, it is possible to accumulate more leaked electrolyte.

  The outer can 70 and the sealing plate 80 can be formed using, for example, a metal plate such as iron, stainless steel, or aluminum, a steel plate obtained by applying nickel plating to iron, a steel plate obtained by applying aluminum plating, or the like. Since iron is an inexpensive material, it is preferable in terms of price, but in order to ensure long-term reliability, a metal plate made of stainless steel, aluminum, or the like, or a steel plate with aluminum plated with nickel or aluminum plating is used. It is more preferable to use a polished steel plate or the like. In addition to the above, a polymer laminate material (laminate plate) obtained by laminating the surface of a metal plate with a polymer material can also be used. In this case, it is preferable that at least the surface on the inner side of the battery is coated. In addition, the thickness of a metal plate can be about 0.4 mm-about 1.2 mm (for example, about 1.0 mm), for example.

  As shown in FIG. 4, the electrode group 40 includes an outer can 70 such that the positive electrode 10 (see FIG. 5) and the negative electrode 20 (see FIG. 5) face the bottom surface 71 of the outer can 70. It is stored inside. As shown in FIG. 4, the current collector exposed portion 11 a (see FIG. 7) of the positive electrode 10 and the current collector exposed portion 21 a (see FIG. 9) of the negative electrode 20 are respectively connected to the outer can via the current collector lead 5. 70 are electrically connected to electrode terminals 74. The current collector lead 5 may be made of the same material as the current collector, but may be made of a different material.

  As shown in FIG. 13, the opening 73 of the outer can 70 is double-wrapped and sealed with the sealing plate 80. Specifically, the sealing plate 80 is attached to the outer can 70 by crimping the tip portion of the folded portion 83 of the sealing plate 80 so as to be wound around the container folding portion 75 of the outer can 70. The sealing plate 80 seals the opening 73 over the entire circumference. In addition, it is possible to obtain higher airtightness by applying a sealing material (not shown) to the part to be crimped. The sealing plate 80 is attached with a sealing strength at which the pressure resistance of the sealing portion is equal to or higher than the operating pressure of the safety valve 85 so that the outer container 60 does not open before the safety valve 85 operates.

  Further, the panel portion 81 of the sealing plate 80 is located below the peripheral edge of the opening 73 of the outer can 70 by the chuck wall portion 82 (on the bottom surface 71 side) by a predetermined distance. Thereby, the electrode group 40 (laminated body 40a) is pressed in the stacking direction (depth direction of the outer can 70; Z direction) by the outer can 70 and the sealing plate 80 in a state of being accommodated in the outer container 60. The positive electrode 10 and the negative electrode 20 are in close contact with the separator 30 in between.

  The nonaqueous electrolytic solution is injected, for example, under reduced pressure from the liquid injection hole 84 after the opening 73 of the outer can 70 is sealed with the sealing plate 80. And after installing the metal ball | bowl 90 (refer FIG. 3) of the diameter substantially the same as the liquid injection hole 84 in the liquid injection hole 84, the liquid injection hole 84 is sealed by resistance welding, laser welding, etc. If the cap of the safety valve 85 is not attached at the time of liquid injection and the pressure is reduced from the safety valve 85, the liquid injection speed can be increased. In this case, it is preferable that the liquid injection hole 84 and the safety valve 85 are arranged apart from each other.

  The lithium ion secondary battery 100 according to the first embodiment configured as described above can be suitably used as a stationary power storage battery (secondary battery module to be described later) that requires a long life. Moreover, it can use suitably also as storage batteries for vehicle-mounted use, such as a hybrid vehicle (HEV) and an electric vehicle (EV). In addition, the lithium ion secondary battery 100 according to the first embodiment is suitable for a storage battery having a single battery capacity of 10 Ah or more, and particularly suitable for a large capacity storage battery having a single battery capacity of 50 Ah or more.

  Conventional lithium-ion secondary batteries for mobile phones or notebook PCs have a single battery capacity of about 0.5 to 3 Ah, and the amount of electrolyte used is several to tens of ml. But it wasn't a big problem. However, in the case of a storage battery for stationary power storage, and an in-vehicle storage battery such as a hybrid vehicle (HEV) or an electric vehicle (EV), the unit cell capacity is 10 Ah or more, from about 20, 30 Ah to 120, 150 And a large battery of about 200 Ah. Moreover, the amount of the electrolyte is 100 mL or more, and is about 2L and 3L from about 200 and 300 mL. In this way, when the battery is enlarged, the risk when the electrolyte leaks becomes very high, and means that can suppress it are very effective safety measures.

  An example of the lithium ion secondary battery 100 according to the first embodiment will be described below together with its manufacturing method.

[Production of positive electrode]
First, the active material LiFePO ₄ (90 parts by weight), the conductive material acetylene black (5 parts by weight), the binder styrene butadiene rubber (3 parts by weight), and the thickener CMC (2 parts by weight). Then, water was added as appropriate and dispersed to prepare a positive electrode mixture slurry. Next, the positive electrode mixture slurry was uniformly applied to both surfaces of an aluminum current collector (positive electrode current collector) having a thickness of 20 μm and dried, and then compressed by a roll press to a thickness of 400 μm. Finally, the positive electrode (positive electrode plate) was produced by cutting into a desired size. The area of the positive electrode active material layer applied was 150 mm long and 300 mm wide, and the positive electrode (positive electrode current collector) was 150 mm long and 310 mm wide.

[Production of negative electrode]
After mixing natural graphite (98 parts by weight) as an active material, styrene butadiene rubber (1 part by weight) as a binder, and CMC (1 part by weight) as a thickener, water is appropriately added and dispersed. Thus, a negative electrode mixture slurry was prepared. Next, this negative electrode mixture slurry was uniformly applied on both sides of a copper current collector (negative electrode current collector) having a thickness of 16 μm and dried, and then compressed by a roll press to a thickness of 350 μm. Finally, the negative electrode (negative electrode plate) was produced by cutting into a desired size. The size of the area where the active material layer of the negative electrode was applied was 154 mm long and 304 mm wide, and the negative electrode (negative electrode current collector) was 154 mm long and 314 mm wide.

[Preparation of non-aqueous electrolyte]
A non-aqueous electrolyte was prepared by dissolving 1 mol / L of LiPF ₆ in a mixed solution (solvent) obtained by mixing EC, DMC, and EMC at a volume ratio of 3: 4: 3.

[Assembly of secondary battery]
By laminating the positive electrode plate and the negative electrode plate in the order of the positive electrode plate, the separator, the negative electrode plate, the separator,... So that the separator enters between the positive electrode plate and the negative electrode plate. Formed. At this time, 50 positive plates and 51 negative plates were used so that the negative plate was located outside the positive plate. Further, by using 102 separators, the separator was positioned on the outermost side of the electrode group (laminated body).

  As the separator, a microporous polyethylene film having a thickness of 20 μm was used. The size of the separator was 160 mm in length and 310 mm in width so as to be larger than the size on which the active material layers of the positive electrode plate and the negative electrode plate were applied.

  As the outer container, an outer can and a sealing plate were formed by processing a steel plate having a thickness of about 0.8 mm plated with nickel. The inner diameter of the outer can was 180 mm in the bottom portion, 350 mm in the bottom portion, and 40 mm in depth. The outer can was formed with an aluminum positive electrode terminal using stainless steel as a pedestal portion and a copper negative electrode terminal using stainless steel as a pedestal portion.

  And after accommodating an electrode group (laminated body) in this exterior can, the sealing board was mounted and the battery was sealed by double winding. The depth of the recess formed by the panel portion of the sealing plate after sealing and the chuck wall portion (height of the chuck wall portion) was 12 mm. Moreover, it comprised so that a pressing force might be added to the electrode group to the lamination direction by attaching a sealing board. At this time, a pressing force was applied to the electrode group with the sealing plate so that the ratio of the pushing amount to the thickness of the electrode group in the stacking direction was 10%. Specifically, the sealing plate was fixed at a position where it was pushed in by about 1 mm from a state where the electrode group and the sealing plate were in direct or indirect contact.

  Subsequently, a predetermined amount of non-aqueous electrolyte was injected under reduced pressure from a φ2 mm injection hole provided in advance on the sealing plate. After the liquid injection, a metal sphere having the same diameter as the liquid injection hole was placed in the liquid injection hole, and the liquid injection hole was sealed by resistance welding, whereby the lithium ion secondary battery 100 was obtained. This lithium ion secondary battery 100 had a rated capacity of 100 Ah.

  In the above-described embodiment, an example in which the present invention is applied to a stacked lithium ion secondary battery has been described. However, the present invention is not limited thereto, and for example, the present invention is applied to a wound lithium ion secondary battery. May be applied.

  In the above embodiment, an example in which the present invention is applied to a lithium ion secondary battery (non-aqueous electrolyte secondary battery) which is an example of a secondary battery has been described. The present invention may be applied to nonaqueous electrolyte secondary batteries other than secondary batteries. Moreover, you may apply this invention to secondary batteries other than a nonaqueous electrolyte secondary battery. Furthermore, the present invention can also be applied to secondary batteries that will be developed in the future.

  In the above embodiment, an example in which the active material layer is formed on both surfaces of the current collector has been described. However, the present invention is not limited to this, and the active material layer may be formed only on one surface of the current collector. . Moreover, you may comprise so that the electrode (positive electrode, negative electrode) which formed the active material layer only in the single side | surface of a collector may be included in a part of electrode group. Moreover, you may disperse | swell the swelling resin which has swelling property with respect to a non-aqueous electrolyte in the active material layer of an electrode. Examples of swellable resins include nitrile butadiene rubber (NBR), styrene butadiene rubber (SBR), carboxymethyl cellulose (CMC), polyvinylidene fluoride (PVdF), polyvinyl alcohol (PVA), polyethylene oxide (PEO), propylene oxide, and polystyrene. A resin comprising at least one selected from polymethyl methacrylate can be used.

  In the above embodiment, an example in which the opening of the outer can is double-wrapped with a sealing plate is shown. However, the present invention is not limited to this, and the sealing method of the outer can is other than the double-wrapping seal. This method may be used. For example, the outer can may be sealed by welding the sealing plate to the outer can.

  In the above embodiment, the negative electrode (negative electrode active material layer) is configured to be larger than the positive electrode (positive electrode active material layer). However, the present invention is not limited to this, and the positive electrode (positive electrode) The active material layer) and the negative electrode (negative electrode active material layer) may be configured to have the same size, and the positive electrode (positive electrode active material layer) is larger than the negative electrode (negative electrode active material layer). You may comprise.

  In the above embodiment, the example in which the positive electrode and the negative electrode are arranged so that the current collector exposed portion of the positive electrode and the current collector exposed portion of the negative electrode are located on the opposite sides is shown. The positive electrode and the negative electrode may be arranged so that the positive electrode current collector exposed portion and the negative electrode current collector exposed portion are located on the same side.

  In the above embodiment, an example is shown in which the current collector exposed portion is formed at one end of the current collector. However, the present invention is not limited to this, and the current collector exposed portion is, for example, a current collector. It may be formed at both ends.

  In the above embodiment, an example in which the shape of the storage container is a rectangle has been described. However, the present invention is not limited to this, and may be a shape such as a circle, an ellipse, or a polygon.

  Moreover, although the example which made circular the shape of a safety valve was shown in said embodiment, this invention is not limited to this, Shapes, such as an ellipse and a polygon, may be sufficient. The structure of the safety valve may be other than the cap.

(Second Embodiment)
FIG. 14 is a schematic sectional side view of the secondary battery module according to the second embodiment of the present invention. The secondary battery module 200 of the second embodiment has a housing 201 having a substantially rectangular parallelepiped appearance, and an assembled battery 202 in which the lithium ion secondary battery 100 of the first embodiment is stacked in the housing 201 is accommodated. ing.

  As a material of the housing 201, a metal or resin having a strength capable of withstanding the weight of the assembled battery 202 can be used. In addition, when installed outdoors, weather resistance is also required. The housing 201 need not be completely sealed. The casing 201 is divided into a lower chamber that houses the lithium ion secondary battery 100 and the like, and an upper chamber that houses the control unit.

  The lower chamber has a plurality of shelves 203 for storing the lithium ion secondary batteries 100 one by one. The shelf 203 is a drawer type, and the lithium ion secondary battery 100 is fixed to the shelf 203 with a hook-and-loop fastener or the like.

  Thus, by arranging the lithium ion secondary batteries 100 on the shelf 203 one by one, the lithium ion secondary batteries 100 are not stacked with each other, so the lower lithium ion secondary battery 100 is deformed by the weight. There is no fear. In addition, the lithium ion secondary battery 100 can be easily taken in and out of the housing 201, and workability is improved. Further, by stacking the lithium ion secondary battery 100, a vertically long casing 201 is obtained, and the installation area can be reduced.

  Further, since the interval between the shelves 203 is higher than the height of the lithium ion secondary battery 100, a space is formed above each lithium ion secondary battery 100, that is, above the recess of the sealing plate 80. With this space, a space for opening the safety valve 85 and a space for storing the leaked electrolyte can be secured. Moreover, the cooling effect of the lithium ion secondary battery 100 is also acquired. Even if the configuration is other than the shelf, the same effect can be obtained if the lithium ion secondary battery 100 can be arranged so that a space is formed above the recess of the sealing plate 80. For example, the lithium ion secondary batteries 100 may be arranged in the planar direction.

  The assembled battery 202 is obtained by stacking lithium ion secondary batteries 100 and appropriately connecting electrode terminals 74. The number of lithium ion secondary batteries 100 constituting the assembled battery is not particularly limited and may be two or more. For example, in FIG. 14, 20 lithium ion secondary batteries 100 are connected in series.

  A sensor 204 for detecting the electrolyte gas is installed on the top surface of the lower chamber. The sensor 204 here may be a sensor that detects a component that volatilizes first when the temperature of the electrolytic solution rises. As in the above embodiment, the volume ratio of EC, DMC, and EMC is 3: 4: 3. In the case of the electrolytic solution mixed in (4), a sensor for detecting DMC may be used. The sensor 204 may be disposed at an appropriate position depending on whether the gas of the electrolyte to be detected rises or falls.

  At the bottom of the lower chamber, that is, below the assembled battery 202, a receiving tray 205 for storing the leaked electrolyte is provided. The tray 205 is larger than the lithium ion secondary battery 100 in plan view, and when the lithium ion secondary battery 100 of the above embodiment is used, 20 pieces are assumed to leak from each lithium ion secondary battery 100 up to about 100 mL. The total of the minutes may be about 2L.

  As the material of the tray 205, the same material as that of the outer container 60 of the lithium ion secondary battery 100 can be used. In this way, by installing the tray 205, even if the electrolyte overflows from any recess of the lithium ion secondary battery 100, it will eventually accumulate in the tray 205 and flow out of the housing 201. Can be prevented.

  The upper chamber is provided with a notification unit 206 that notifies that when the sensor 204 detects, and a breaker 207 that shuts off the power system in the secondary battery module 200 when the sensor 204 detects, Each is connected to the sensor 204 via a communication line. The breaker 207 is connected between the assembled battery 202 and the input / output terminal 208.

  The notification unit 206 may be configured to control so as to emit a warning sound from a speaker provided in the secondary battery module 200, or to send a warning message to an operation panel for remotely operating the secondary battery module 200 from a room or the like. Even if it is controlled to display, control to emit a warning sound from a speaker provided near the operation panel, or control to turn on a warning light provided near the operation panel Good.

  For example, when the sensor 204 detects, it may be controlled so that the breaker 207 is dropped after elapse of a predetermined time after operating the notification unit 206 to warn the user. As a result, the breaker 207 can be prevented from falling without any notice to the user, and the user can normally stop the electrical device connected to the secondary battery module 200 between the warning and the breaker 207 falling. Can be safely stopped by the method.

  Note that the notification unit 206 is not always necessary, and the notification unit 206 may be omitted, and the breaker 207 may be dropped immediately when the sensor 204 detects it. Thus, when the sensor 204 detects, the breaker 207 is finally dropped to shut off the power system, thereby preventing the occurrence of sparks as a fire and preventing the electrolyte from being ignited. Can increase the sex.

  Next, the safety of the secondary battery module 200 was verified. First, when the secondary battery module 200 was overcharged 130%, the safety valve 85 was opened, but no leakage of the electrolyte was observed. Next, when 150% was overcharged, the safety valve 85 was opened, the electrolytic solution accumulated in the recess of the sealing plate 80, the sensor detected, and the breaker was shut off. Next, when overcharged by 200%, the safety valve 85 was opened, the electrolyte overflowed from the recess of the sealing plate 80 and accumulated in the tray, the sensor detected, and the breaker was shut off. Thus, in any case, the electrolyte does not leak to the outside of the secondary battery module, and safety is ensured.

(Third embodiment)
FIG. 15 is a schematic sectional side view of the secondary battery module according to the third embodiment of the present invention. The secondary battery module 300 of the third embodiment has a casing 201 having an approximately rectangular parallelepiped appearance, and an assembled battery 202 in which the lithium ion secondary battery 100 of the first embodiment is stacked in the casing 201 is accommodated. ing. The third embodiment differs from the second embodiment in the installation location of the sensor 304. In addition, the same code | symbol is attached | subjected to the structure similar to 2nd Embodiment, and the detailed description is abbreviate | omitted.

  A sensor 304 that detects a gas of one or more components of the electrolytic solution is installed in the lower chamber of the casing 201 below the assembled battery 202 and above the tray 205 and on the inner wall of the casing 201. The sensor 304 only needs to be below the assembled battery 202, and there is no problem whether it is above or below the tray 205. For example, the sensor 304 is preferably a sensor that detects a component that volatilizes first when the temperature of the electrolytic solution rises.

  This embodiment is particularly effective when the gas descends when it volatilizes, such as an electrolytic solution in which DEC, DMC, and EMC are mixed.

  As described above, by providing the sensor 304 below the assembled battery 202, it is possible to quickly detect when the electrolyte gas tends to accumulate in the lower part of the secondary battery module, which is effective in ensuring safety.

(Fourth embodiment)
FIG. 16 is a schematic sectional side view of the secondary battery module according to the fourth embodiment of the present invention, and FIG. 17 is a bottom view of the sensor mounting member to which the sensor according to the fourth embodiment of the present invention is mounted. The secondary battery module 400 of the fourth embodiment has a casing 201 having a substantially rectangular parallelepiped appearance, and the assembled battery 202 in which the lithium ion secondary battery 100 of the first embodiment is stacked in the casing 201 is accommodated. ing. The fourth embodiment is different from the second or third embodiment in the installation location of the sensor 304. In addition, the same code | symbol is attached | subjected to the structure similar to 2nd or 3rd Embodiment, and the detailed description is abbreviate | omitted.

  A sensor 304 is installed in the lower chamber of the housing 201 below the assembled battery 202 and above the tray 205. The sensor 304 is attached to a sensor attachment member 403 that is provided across the opposing inner side walls of the housing 201. The sensor attachment member 403 is, for example, a rectangular plate-like member as shown in FIG. 17, and the sensor 304 is fixed near the center on the lower surface side with an adhesive, a screw, or the like. The shape of the sensor mounting member 403 is not particularly limited, and for example, a plate-like member that completely partitions the inside of the housing 201, a plate-like member that partitions a part of the housing 201, and the inner wall facing the housing 201 It may be a rod-like member or the like provided over the area.

  The sensor mounting member 403 has a plurality of holes 403a through which the electrolyte gas can pass. For example, as shown in FIG. 17, the holes 403 a are formed so as to penetrate the sensor attachment member 403 in the up-down direction, eight on each side of the sensor 304. In FIG. 17, the planar shape of the hole 403a is circular, but the shape is not particularly limited, and may be an ellipse or a polygon. Moreover, a slit shape may be sufficient. By providing the hole 403a, the volatilized electrolyte gas passes through the hole 403a and is detected by the sensor 304.

  The sensor 304 only needs to be below the assembled battery 202, and there is no problem whether it is above or below the tray 205. The sensor 304 may be provided on the upper surface side of the sensor mounting member 403.

  This embodiment is particularly effective when the gas descends when it volatilizes, such as an electrolytic solution in which DEC, DMC, and EMC are mixed.

  As described above, by providing the sensor 304 below the assembled battery 202, it is possible to quickly detect when the electrolyte gas tends to accumulate in the lower part of the secondary battery module, which is effective in ensuring safety. Further, by providing the hole 403a in the sensor mounting member 403, when the electrolyte is volatilized, the gas passes through the hole 403a and is detected by the sensor 304 more quickly.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

5 Current collector lead 10 Positive electrode (electrode)
DESCRIPTION OF SYMBOLS 11 Positive electrode collector 11a Current collector exposed part 12 Positive electrode active material layer 20 Negative electrode (electrode)
DESCRIPTION OF SYMBOLS 21 Negative electrode collector 21a Current collector exposed part 22 Negative electrode active material layer 30 Separator 40 Electrode group 40a Laminate 60 Outer container 70 Outer can (storage container)
71 Bottom surface portion 71a Outer bottom surface 72 Side wall portion 73 Opening portion 74 Electrode terminal 75 Container return portion 80 Sealing plate (sealing body)
81 Panel part 81a Outer surface 82 Chuck wall part 83 Folding part 84 Injection hole 85 Safety valve 100 Lithium ion secondary battery (secondary battery)
200, 300, 400 Secondary battery module 201 Case 202 Assembly battery 203 Shelf 204, 304 Sensor 205 Receptacle 206 Notification section 207 Breaker 208 Output / input terminal 403 Sensor mounting member 403a Hole

Claims (10)

An electrode group including a positive electrode and a negative electrode;
A storage container for storing the electrode group; a sealing body that seals the opening of the storage container over the entire circumference; a recess formed on the outer top surface of the sealing body; and a safety valve provided in the recess. An outer container containing,
A secondary battery comprising: an electrolytic solution directly filled in the outer container.   The secondary battery according to claim 1, wherein the recess is formed to face the entire opening of the storage container. An assembled battery in which the secondary batteries according to claim 1 or 2 are stacked;
A secondary battery module comprising: a housing that houses the assembled battery.   The secondary battery module according to claim 3, wherein the assembled battery has a space above the recess.   The secondary battery module according to claim 4, wherein the space is formed by arranging the secondary batteries on a plurality of shelves formed in the housing. A sensor for detecting the gas of the electrolyte;
The secondary battery module according to claim 3, further comprising a breaker that shuts off the power system when the sensor detects the secondary battery module. A sensor for detecting the gas of the electrolyte;
A secondary battery module according to any one of claims 3 to 5, further comprising: a notification unit that notifies the fact when the sensor detects.   The secondary battery module according to claim 6, wherein the sensor is provided below the assembled battery.   9. The secondary device according to claim 8, further comprising a sensor mounting member that is provided over opposing inner side walls of the housing and has a hole through which the sensor can be mounted and the electrolyte gas can pass. Battery module.   The secondary battery module according to any one of claims 3 to 9, further comprising a receiving tray for storing the leaked electrolyte under the assembled battery.

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