JP2011238456A - Secondary battery, and photovoltaic power generation system, wind turbine power generation system, and vehicle comprising secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a secondary battery which can improve rigidity and life properties.SOLUTION: A lithium ion secondary battery (secondary battery) comprises an electrode group 50 including a positive electrode 10 and negative electrodes 20, and an outer container 100 sealing the electrode group 50 along with nonaqueous electrolyte. The outer container 100 includes an outer can 60 accommodating the electrode group 50, and a sealing plate 90 sealing the outer can 60. In the sealing plate 90, projections 71, while protruding toward the electrode group 50 side, having space parts 73 which are allowed to store the nonaqueous electrolyte for replenishment on a face side opposite to the electrode group 50 side are formed. Moreover, each projection 71 has a hole 74 for supplying the nonaqueous electrolyte for replenishment, which is stored in the space part 73, to the electrode group 50 side, and this hole 74 is occluded by a sealing member made of resin material permeable of the nonaqueous electrolyte for replenishment to the electrode group 50 side.

Description

  The present invention relates to a secondary battery and a solar power generation system, a wind power generation system, and a vehicle including the secondary battery.

  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 compact, lightweight, high energy density, and repeated charging and discharging over a long period of time. There is a strong demand for the development of rechargeable batteries. As a secondary battery that satisfies these requirements, a lithium ion secondary battery having a higher energy density than other secondary batteries is the most promising, and various studies have been conducted to develop a better lithium ion secondary battery. Has been promoted.

In recent years, lithium ion secondary batteries have been used for power storage applications such as solar power generation systems and wind power generation systems in consideration of environmental problems such as global warming. Furthermore, as measures against carbon dioxide (CO ₂ ) reduction and energy problems, there is an increasing expectation for the spread of hybrid vehicles (HEV: Hybrid Electric Vehicle) and electric vehicles (EV: Electric Vehicle) with low fuel consumption and low exhaust gas. Development and commercialization of lithium ion secondary batteries targeting on-vehicle batteries are also underway.

  Thus, the demand for lithium ion secondary batteries not only for portable devices such as mobile phones but also for large-sized power such as electric vehicles is increasing. As the demand for lithium ion secondary batteries increases, a longer life such as a large capacity and 500 cycles or more has been demanded.

  Here, in order to apply the lithium ion secondary battery to the above-mentioned application, when trying to increase the size or thickness of the battery, the mechanical strength of the outer container is lowered, and the battery is likely to be deformed. Arise. Therefore, conventionally, a secondary battery in which a rib is provided on the inner surface of the battery can has been proposed in order to improve the rigidity of the battery can (exterior container) (see, for example, Patent Document 1).

JP 2005-353472 A

  However, the secondary battery proposed in Patent Document 1 has a problem that although it is possible to improve the rigidity of the battery can (exterior container), it is difficult to improve the life characteristics of the battery.

  The present invention has been made to solve the above problems, and one object of the present invention is to provide a secondary battery capable of improving rigidity and life characteristics, and the secondary battery. To provide solar power generation system, wind power generation system, vehicle.

  To achieve the above object, a secondary battery according to a first aspect of the present invention includes an electrode group including a positive electrode and a negative electrode disposed so as to face the positive electrode, and an exterior that encloses the electrode group together with an electrolyte. A container and a convex portion provided on the outer container and projecting toward the electrode group side and having a space portion on the surface side opposite to the electrode group side where a replenishing electrolyte is disposed. The exterior container includes a storage container that stores the electrode group and a sealing body that seals the storage container. Further, the convex part includes a leaking part for leaking the replenishing electrolyte solution arranged in the space part to the electrode group side, and at least one of the largest faces among the faces constituting the sealing body and the storage container. Is provided.

  In the secondary battery according to the first aspect, as described above, by providing a convex portion on at least one of the largest surfaces constituting the sealing body and the storage container, the convex portion provides mechanical strength. It is possible to reinforce a large-area portion that tends to decrease. Thereby, the rigidity of an exterior container can be improved.

  In the first aspect, the convex portion is formed so as to protrude toward the electrode group side and to have a space portion on the surface side opposite to the electrode group side. The liquid can be stored. Then, by forming the leakage portion in the convex region, the electrolytic solution stored in the space portion can be supplied (supplemented) to the electrode group side through the leakage portion.

  Here, since the discharge capacity can be recovered by re-injecting a new electrolyte into the secondary battery whose discharge capacity has decreased with the progress of the charge / discharge cycle, the electrolyte stored in the space is leaked. By supplying to the electrode group side through the part, the charge / discharge cycle characteristics can be improved.

  Therefore, in the first aspect, by configuring as described above, the life characteristics can be improved while increasing the rigidity of the outer container.

  In the secondary battery according to the first aspect described above, preferably, the sealing body is a first plate-like member in which a convex portion is formed, and a second plate-like member attached to the first plate-like member so as to cover the space portion. Member. If comprised in this way, since the rigidity of a sealing body can be improved more, when welding a sealing body and a storage container, it can suppress that distortion arises in a sealing body. In addition, since a welding distance becomes long when a secondary battery is enlarged, distortion becomes easy to produce a sealing body at the time of welding. On the other hand, since it can suppress that a sealing body produces distortion if comprised as mentioned above, even when a battery is enlarged, a sealing body and a storage container can be welded easily. Thereby, since the secondary battery can be easily increased in size, a large-capacity secondary battery can be easily obtained. Moreover, since the sealing body and the storage container can be firmly fixed by suppressing distortion of the sealing body, reliability and safety can be improved.

  In the secondary battery according to the first aspect described above, preferably, the leakage portion seals the hole provided in the convex portion and the hole, and leaks the electrolyte in the space to the electrode group side. A stop member. If comprised in this way, the electrolyte solution stored by the space part can be easily supplied to the electrode group side. Thereby, charge / discharge cycle characteristics can be easily improved. In addition, by supplying the electrolyte stored in the space to the electrode group side, it is possible to suppress the electrolyte from draining, so it is possible to easily suppress the deterioration of battery performance due to the electrolyte draining. can do.

  In this case, the sealing member is preferably made of a resin material that swells with the electrolytic solution and leaks the electrolytic solution in the space portion to the electrode group side after a predetermined time has elapsed. If comprised in this way, since the electrolyte solution stored in the space part can be leaked out to the electrode group side by deterioration of the resin by the electrolyte solution, the electrolyte solution can be easily replenished to the electrode group. . As a result, the electrolyte stored in the space can be more easily supplied to the electrode group side.

  In the configuration in which the sealing member is made of a resin material, the resin material is configured to include at least one selected from styrene butadiene rubber, ethylene propylene diene monomer, butyl rubber, silicon rubber, and fluororesin-containing rubber. preferable.

  In the secondary battery according to the first aspect, the convex portion is preferably configured to have a groove shape when viewed from the side opposite to the electrode group. If comprised in this way, electrolyte solution can be stored in a groove | channel and the rigidity of an exterior container can be raised easily.

  In the secondary battery according to the first aspect, preferably, a surface of the outer container on which the convex portion is provided is formed in a substantially rectangular shape when seen in a plan view, and the convex portion extends in the long side direction. Is formed. If comprised in this way, the rigidity of an exterior container can be raised effectively.

  In the secondary battery according to the first aspect, the surface of the outer container on which the convex portion is provided is formed in a substantially rectangular shape when seen in a plan view, and the convex portion extends in a direction intersecting the long side direction. It may be formed as follows.

  In the secondary battery according to the first aspect, the surface of the outer container on which the convex portion is provided is formed in a substantially rectangular shape including a long side and a short side when seen in a plan view, and the convex portion has a substantially rhombus shape. You may form so that a shape may be comprised.

  In this case, it is preferable that the convex portions constituting the approximately rhombus shape are arranged so that each diagonal line is parallel to the long side and the short side of the outer container.

  In the secondary battery according to the first aspect, preferably, the convex portion includes one or more leakage portions. That is, only one leakage part may be formed on the convex part, or a plurality of leakage parts may be formed.

  In the secondary battery according to the first aspect, preferably, a plurality of the convex portions are formed, and a leakage portion is formed in each of the plurality of convex portions. If comprised in this way, while being able to store the electrolyte solution for replenishment in each of the space parts provided by formation of a convex part, the electrolyte solution stored in each of the space parts is stored in each convex part. It can supply to the electrode group side through the leak part provided in. For this reason, since the quantity of the electrolyte solution which can be stored in a space part can be increased, electrolyte solution can be supplied to the electrode group side over a long period of time. Thereby, charging / discharging cycle characteristics can be improved more easily. Moreover, the rigidity of an exterior container can be easily raised by forming the said convex part in multiple numbers.

  In the configuration provided with the plurality of protrusions, preferably, the surface of the outer container on which the protrusions are provided is formed in a substantially rectangular shape when seen in a plan view, and at least a part of the plurality of protrusions is , So as to extend in the long side direction. If comprised in this way, the rigidity of an exterior container can be improved more effectively.

  In the configuration in which the plurality of projections are provided, the surface of the exterior container on which the projections are provided is formed in a substantially rectangular shape when seen in a plan view, and at least some of the plurality of projections have long sides. You may form so that it may extend in the direction which cross | intersects a direction.

  In the configuration in which the plurality of projections are provided, at least a part of the plurality of projections can be formed so as to form a substantially rhombus shape when seen in a plan view.

  In the secondary battery according to the first aspect, preferably, the leakage portion is formed at a position not in contact with the electrode group. If comprised in this way, it can suppress that the problem that an electrode group is damaged resulting from a leak part and an electrode group contacting is produced. Thereby, generation | occurrence | production of the internal short circuit resulting from damage of an electrode group can be suppressed. As a result, it is possible to suppress deterioration of charge / discharge cycle characteristics and reliability due to occurrence of an internal short circuit. If an internal short circuit occurs during battery assembly, the yield may be reduced. Therefore, the yield improvement effect can also be obtained by suppressing the occurrence of an internal short circuit.

  In the secondary battery according to the first aspect, preferably, the corners of the convex portions are rounded or chamfered. If comprised in this way, the damage of the electrode group by the contact of a convex part and an electrode group can be suppressed effectively. Thereby, generation | occurrence | production of an internal short circuit can be suppressed effectively.

  In the secondary battery according to the first aspect, it is preferable that the width of the space formed by the convex portion is 5 mm or more. If comprised in this way, it can make it easy to suppress the damage of the electrode group by the contact of a convex part and an electrode group. Moreover, if comprised in this way, it can suppress that the problem that the volume of a space part becomes small resulting from the width | variety of a space part becoming too small arises. As a result, it is possible to suppress the inconvenience that it becomes difficult to recover the discharge capacity because the amount of the electrolytic solution stored in the space portion becomes too small.

  The secondary battery according to the first aspect preferably further includes a separator disposed between the positive electrode and the negative electrode, and the electrode group is configured in a stacked structure by sequentially stacking the positive electrode, the separator, and the negative electrode. Yes. With such a configuration, it is possible to obtain a highly reliable stacked secondary battery having high rigidity and excellent life characteristics.

  In the secondary battery according to the first aspect, the surface of the storage container having the largest area is the bottom surface, and the positive electrode and the negative electrode are stored in the storage container so as to face the bottom surface. preferable. As described above, if the surface of the storage container having the largest area is the bottom surface portion and the opening for storing the electrode is provided on the side facing the bottom surface portion, the large area electrode can be easily stored. Thereby, manufacture of a high capacity | capacitance secondary battery can be made easy. Further, when the storage container is made of a metal can, there is a limit to the deep drawing of the can, and the material to be used is also limited. In addition, a plurality of expensive dies are required. On the other hand, if a secondary battery is manufactured using a storage container having a bottom area with a large area as described above, it is advantageous in this respect as well. In other words, if configured as described above, the degree of freedom in material selection and workability during manufacturing can be improved.

  A solar power generation system according to a second aspect of the present invention is a solar power generation system including the secondary battery according to the first aspect. As described above, if the secondary battery according to the first aspect is used for power storage for the solar power generation system, the life of the power storage facility can be easily extended, and the cost of the entire system can be reduced. Can be planned.

  A wind power generation system according to a third aspect of the present invention is a wind power generation system including the secondary battery according to the first aspect. As described above, if the secondary battery according to the first aspect is used for power storage for the wind power generation system, the life of the power storage facility can be easily extended and the cost of the entire system can be reduced. be able to.

  A vehicle according to a fourth aspect of the present invention is a vehicle including the secondary battery according to the first aspect.

  As described above, according to the present invention, a secondary battery capable of improving rigidity and life characteristics, and a solar power generation system, a wind power generation system, and a vehicle including the secondary battery can be easily obtained. it can.

1 is an exploded perspective view of a lithium ion secondary battery according to a first embodiment of the present invention. 1 is an exploded perspective view of a lithium ion secondary battery according to a first embodiment of the present invention. 1 is an exploded perspective view of a lithium ion secondary battery according to a first embodiment of the present invention. 1 is an overall perspective view of a lithium ion secondary battery according to a first embodiment of the present invention. 1 is a plan view of a lithium ion secondary battery according to a first embodiment of the present invention. 1 is a plan view of a lithium ion secondary battery according to a first embodiment of the present invention (a diagram in which a sealing plate is omitted). FIG. It is the perspective view which showed the structure of the electrode group of the lithium ion secondary battery by 1st Embodiment of this invention. It is the perspective view which showed the structure of the positive electrode of the lithium ion secondary battery by 1st Embodiment of this invention. It is the top view which showed the structure of the positive electrode of the lithium ion secondary battery by 1st Embodiment of this invention. It is the perspective view which showed the structure of the negative electrode of the lithium ion secondary battery by 1st Embodiment of this invention. It is the perspective view which showed the structure of the negative electrode of the lithium ion secondary battery by 1st Embodiment of this invention. It is a top view of the separator of the lithium ion secondary battery by a 1st embodiment of the present invention. 1 is a perspective view of an outer can of a lithium ion secondary battery according to a first embodiment of the present invention. It is the top view (figure of the state seen from the side (concave part side) opposite to the projection side of a convex part) which showed the 1st tabular member of the sealing board of the lithium ion secondary battery by a 1st embodiment of the present invention. . It is the perspective view (figure of the state seen from the side (concave part side) opposite to the projection side of a convex part) which showed the 1st plate-like member of the sealing board of the lithium ion secondary battery by a 1st embodiment of the present invention. . It is the perspective view which showed the 1st plate-shaped member of the sealing board of the lithium ion secondary battery by 1st Embodiment of this invention (the figure of the state seen from the protrusion side of a convex part). It is sectional drawing which shows the 1st plate-shaped member of the sealing board of the lithium ion secondary battery by 1st Embodiment of this invention (figure corresponding to the cross section along the A3-A3 line | wire of FIG. 15). It is the side view (figure of the state which looked at the 1st plate-like member of Drawing 15 from the C2 direction) which showed the 1st plate-like member of the sealing board of the lithium ion secondary battery by a 1st embodiment of the present invention. It is the top view which showed the 2nd plate-shaped member of the sealing board of the lithium ion secondary battery by 1st Embodiment of this invention. 1 is a cross-sectional view of a sealing plate of a lithium ion secondary battery according to a first embodiment of the present invention (a state in which a nonaqueous electrolyte for replenishment is not stored). It is a top view of the sealing board of the lithium ion secondary battery by 1st Embodiment of this invention. 1 is a cross-sectional view of a sealing plate of a lithium ion secondary battery according to a first embodiment of the present invention (a state in which a nonaqueous electrolyte for replenishment is stored). It is a side view (figure of the state which looked at the sealing board in FIG. 3 from C1 direction) of the sealing board of the lithium ion secondary battery by 1st Embodiment of this invention. It is sectional drawing (figure corresponding to the cross section along the BB line of FIG. 4) of the lithium ion secondary battery by 1st Embodiment of this invention. It is sectional drawing which expanded and showed the D1 part of FIG. It is sectional drawing (figure corresponding to the cross section along the A2-A2 line of FIG. 4) of the lithium ion secondary battery by 1st Embodiment of this invention. It is sectional drawing which expanded and showed the D2 part of FIG. It is sectional drawing of the lithium ion secondary battery by the modification of 1st Embodiment. It is sectional drawing which expanded and showed the D3 part of FIG. It is a disassembled perspective view of the lithium ion secondary battery by 2nd Embodiment of this invention. It is a whole perspective view of the lithium ion secondary battery by 2nd Embodiment of this invention. FIG. 32 is a cross-sectional view of the lithium ion secondary battery according to the second embodiment of the present invention (a view corresponding to a cross section taken along line A4-A4 of FIG. 31). It is the top view (figure of the state seen from the side (concave part side) opposite to the projection side of a convex part) which showed the 1st plate-like member of the sealing board of the lithium ion secondary battery by a 2nd embodiment of the present invention. . It is the perspective view which showed the 1st plate-shaped member of the sealing board of the lithium ion secondary battery by 2nd Embodiment of this invention. It is a top view of the 1st plate-shaped member which comprises the sealing board of the lithium ion secondary battery by 3rd Embodiment of this invention. It is a perspective view of the 1st plate-shaped member which comprises the sealing board of the lithium ion secondary battery by 3rd Embodiment of this invention. It is a top view of the 1st plate-shaped member which comprises the sealing board of the lithium ion secondary battery by 4th Embodiment of this invention. It is a perspective view of the 1st plate-shaped member which comprises the sealing board of the lithium ion secondary battery by 4th Embodiment of this invention. It is a top view of the 1st plate-shaped member which comprises the sealing board of the lithium ion secondary battery by 5th Embodiment of this invention. It is a perspective view of the 1st plate-shaped member which comprises the sealing board of the lithium ion secondary battery by 5th Embodiment of this invention. It is a top view of the 1st plate-shaped member which comprises the sealing board of the lithium ion secondary battery by 6th Embodiment of this invention. It is a perspective view of the 1st plate-shaped member which comprises the sealing board of the lithium ion secondary battery by 6th Embodiment of this invention. It is a top view of the 1st plate-shaped member which comprises the sealing board of the lithium ion secondary battery by 7th Embodiment of this invention. It is a perspective view of the 1st plate-shaped member which comprises the sealing board of the lithium ion secondary battery by 7th Embodiment of this invention. It is a top view of the 1st plate-shaped member which comprises the sealing board of the lithium ion secondary battery by 8th Embodiment of this invention. It is a perspective view of the 1st plate-shaped member which comprises the sealing board of the lithium ion secondary battery by 8th Embodiment of this invention. It is a top view of the 1st plate-shaped member which comprises the sealing board of the lithium ion secondary battery by 9th Embodiment of this invention. It is a perspective view of the 1st plate-shaped member which comprises the sealing board of the lithium ion secondary battery by 9th Embodiment of this invention. It is a top view of the 1st plate-shaped member which comprises the sealing board of the lithium ion secondary battery by 10th Embodiment of this invention. It is a perspective view of the 1st plate-shaped member which comprises the sealing board of the lithium ion secondary battery by 10th Embodiment of this invention. It is a top view of the 1st plate-shaped member which comprises the sealing board of the lithium ion secondary battery by 11th Embodiment of this invention. It is a perspective view of the 1st plate-shaped member which comprises the sealing board of the lithium ion secondary battery by 11th Embodiment of this invention. It is a top view of the 1st plate-shaped member which comprises the sealing board of the lithium ion secondary battery by 12th Embodiment of this invention. It is a top view of the 1st plate-shaped member which comprises the sealing board of the lithium ion secondary battery by 12th Embodiment of this invention. It is a perspective view of the 1st plate-shaped member which comprises the sealing board of the lithium ion secondary battery by 12th Embodiment of this invention. It is the top view which showed the sealing board (1st plate-shaped member) of Example 1. FIG. It is the top view which showed the sealing board (1st plate-shaped member) of Example 2. FIG. It is the top view which showed the sealing board (1st plate-shaped member) of Example 3. FIG. It is the top view which showed the sealing board (1st plate-shaped member) of Example 4. FIG. It is the top view which showed the sealing board (1st plate-shaped member) of Example 5. FIG. It is the top view which showed the sealing board (1st plate-shaped member) of the comparative example. It is the schematic of the solar energy power generation system by 13th Embodiment of this invention. It is the schematic of the wind power generation system by 14th Embodiment of this invention. It is the schematic of the bicycle with an electric drive function by 15th Embodiment of this invention. It is the schematic of the electric railway vehicle by 16th Embodiment of this invention. It is sectional drawing (the figure which expanded and showed a part) which showed the sealing state of the hole of the convex part in the lithium ion secondary battery by the 1st modification of this invention. It is sectional drawing (the figure which expanded and showed a part) which showed the sealing state of the hole of the convex part in the lithium ion secondary battery by the 2nd modification of this invention. It is the perspective view which showed the lithium ion secondary battery by the 3rd modification of this invention. It is a schematic diagram for demonstrating the liquid injection operation | movement of the lithium ion secondary battery by the 3rd modification of this invention. It is the top view which showed the exterior can of the lithium ion secondary battery by the 4th modification of this invention. It is the top view which showed the exterior can of the lithium ion secondary battery by the 5th modification of this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments embodying the present invention will be described in detail with reference to the drawings. 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 to 3 are exploded perspective views of a lithium ion secondary battery according to a first embodiment of the present invention. FIG. 4 is an overall perspective view of the lithium ion secondary battery according to the first embodiment of the present invention. 5 and 6 are plan views of the lithium ion secondary battery according to the first embodiment of the present invention. 7 to 27 are views for explaining a lithium ion secondary battery according to the first embodiment of the present invention. In FIG. 6, the sealing plate that is originally provided is removed so that the inside of the lithium ion secondary battery can be seen. First, a lithium ion secondary battery according to a first embodiment of the present invention will be described with reference to FIGS.

  The lithium ion secondary battery by 1st Embodiment is a large sized secondary battery which has a square flat shape (refer FIG. 4), as shown in FIGS. 1-4, and the positive electrode 10 (refer FIG. 1) and the negative electrode 20 (refer FIG. 1). An electrode group 50 (see FIG. 1) (see FIG. 1 and FIG. 2), and a metal outer container 100 that encloses the electrode group 50 together with a non-aqueous electrolyte.

  As shown in FIGS. 1 and 7, the electrode group 50 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 so as to face each other with the separator 30 in between. The electrode group 50 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 50 a). . Note that the positive electrodes 10 and the negative electrodes 20 are alternately stacked one by one. The electrode group 50 is configured such that one positive electrode 10 is positioned between two adjacent negative electrodes 20.

  Specifically, the electrode group 50 includes, for example, 24 positive electrodes 10, 25 negative electrodes 20, and 48 separators 30. The positive electrodes 10 and the negative electrodes 20 are alternately sandwiched between the separators 30. Are stacked. Note that a separator 30 is disposed on the outermost side of the electrode group 50 (outside of the outermost negative electrode 20) so as to be insulated from the outer container 100.

  As shown in FIGS. 8 and 9, the positive electrode 10 constituting the electrode group 50 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, a material obtained by treating the surface of aluminum, copper, or the like 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. Examples of the positive electrode active material include an oxide containing lithium. 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). The compound etc. which have the olivine structure represented by these are mentioned. 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 include 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 or 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. A polymer, styrene butadiene rubber, or the like can be used.

  Examples of the solvent for dispersing the positive electrode active material, the conductive material, the binder, and the like include, for example, 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 can be used.

  The positive electrode 10 described above is obtained by mixing a positive electrode active material, a conductive material, a thickener 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. 9, the positive electrode 10 has a rectangular shape in plan view. Specifically, in the first embodiment, the positive electrode 10 has a width w1 in the Y direction of, for example, about 140 mm, and a length g1 in the X direction of, for example, about 250 mm. 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 140 mm, and the length g11 in the X direction is, for example, It is about 235 mm.

  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. A current collector lead 5 (see FIG. 6), which will be described later, is electrically connected to the current collector exposed portion 11a for taking out a current to the outside. The four end portions of the positive electrode active material layer 12 are the same as the end portions of the positive electrode 10 except for one side (the end portion on the current collector exposed portion 11a side) of the two end portions along the Y direction. Match.

  As shown in FIGS. 10 and 11, the negative electrode 20 constituting the electrode group 50 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. For example, when lithium titanate typified by Li ₄ Ti ₅ O ₁₂ is used as the lithium transition metal oxide, the deterioration of the negative electrode 20 is reduced, so that the life of the battery 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. Note that other materials such as a conductive material, a thickening material, and a binder can be the same as the positive electrode active material layer 12 (that can be used for the positive electrode active material layer 12).

  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. 11, the negative electrode 20 has a rectangular shape in plan view, and is formed in a larger plane area than the positive electrode 10 (see FIGS. 8 and 9). Specifically, in the first embodiment, the negative electrode 20 has a width w2 in the Y direction larger than a width w1 of the positive electrode 10 (see FIG. 9), for example, about 142 mm, and is long in the X direction. The length g2 is longer than the length g1 (see FIG. 9) of the positive electrode 10, for example, about 251 mm. In addition, 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 142 mm, and the length g21 in the X direction is, for example, It is about 237 mm.

  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. . A current collector lead 5 (see FIG. 6), which will be described later, is electrically connected to the current collector exposed portion 21a for taking out current to the outside. The four end portions of the negative electrode active material layer 22 are the same as the end portions of the negative electrode 20 except for one side (the end portion on the current collector exposed portion 21a side) of the two end portions along the Y direction. Match.

  The separator 30 constituting the electrode group 50 is preferably a separator having sufficient strength and capable of holding a large amount of electrolyte. From such a viewpoint, polyethylene, polypropylene, having a thickness of 10 μm to 50 μm and a porosity of 30% to 70%, Alternatively, a microporous film or a nonwoven fabric containing an ethylene-propylene copolymer is preferable.

  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.

  The separator 30 has a shape larger than the application region (formation region) of the positive electrode active material layer 12 and the application region (formation region) of the negative electrode active material layer 22. Specifically, as shown in FIG. 12, the separator 30 is formed in a rectangular shape, and the width w3 in the Y direction is, for example, about 145 mm, and the length g3 in the X direction is, for example, about 240 mm. Yes.

  As shown in FIGS. 1 and 7, 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. The separator 30 is laminated between the positive electrode and the negative electrode. In the first embodiment, the formation region of the positive electrode active material layer 12 (positive electrode active material region) is covered with the formation region of the negative electrode active material layer 22 (negative electrode active material region) having a large area. The tolerance is widened.

  The nonaqueous electrolytic solution sealed together with the electrode group 50 in the outer container 100 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, methyl ethyl carbonate, γ-butyrolactone, ethers such as tetrahydrofuran, 2-methyltetrahydrofuran, dioxane, dioxolane, diethyl ether, dimethoxyethane, diethoxyethane, methoxyethoxyethane, dimethyl sulfoxide, sulfolane, Polar solvents such as methylsulfolane, acetonitrile, methyl formate, 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.

  As shown in FIGS. 4 to 6, the exterior container 100 that encloses the electrode group 50 is a large flat rectangular container, and an exterior can 60 that houses the electrode group 50 and the like, and a sealing plate that seals the exterior can 60 90. A sealing plate 90 is attached to the outer can 60 containing the electrode group 50 by laser welding. The outer can 60 is an example of the “storage container” in the present invention, and the sealing plate 90 is an example of the “sealing body” in the present invention.

  The outer can 60 is formed, for example, by performing deep drawing or the like on a metal plate, and has a bottom surface portion 61 and a side wall portion 62. As shown in FIGS. 6 and 13, an opening 63 for inserting the electrode group 50 (see FIG. 6) is provided at one end of the outer can 60 (opposite the bottom surface portion 61). The outer can 60 is formed as a square can, and the surface having the largest area is the bottom surface portion 61.

  The outer can 60 has a size that allows the electrode group 50 to be stored so that the electrode surface thereof faces the bottom surface portion 61. Specifically, the outer can 60 is formed to have a substantially rectangular shape when seen in a plan view. The length W1 in the short side direction (length W1 in the Y direction in FIG. 13) of the outer can 60 is, for example, about 150 mm, and the length L1 in the long side direction in the outer can 60 (the X direction in FIG. 13). The length L1) is, for example, about 300 mm. Moreover, the height H1 (refer FIG. 13) of the armored can 60 is comprised by about 40 mm (depth: about 39 mm), for example.

  As shown in FIGS. 5, 6, and 13, the outer can 60 has two electrode terminals 64 (a positive electrode terminal and a negative electrode terminal) on the side wall portion 62 on one side (long side) in the Y direction. Is formed. One of the electrode terminals 64 is disposed on one end side of the side wall portion 62 in the X direction, and the other of the electrode terminals 64 is disposed on the other end side of the side wall portion 62 in the X direction. In addition, a liquid injection hole 65 for injecting a non-aqueous electrolyte is formed in the side wall 62 where the electrode terminal 64 is formed. The liquid injection hole 65 is formed in a size of φ2 mm, for example. A safety valve 66 for releasing the battery internal pressure is formed in the vicinity of the liquid injection hole 65.

  Further, a folded portion 67 is provided on the periphery of the opening 63 of the outer can 60, and a sealing plate 90 is fixed to the folded portion 67 by welding. The width d (see FIG. 6) of the folded portion 67 is, for example, about 5 mm. For this reason, the length W2 in the short side direction (Y direction) of the outer can 60 including the folded portion 67 is, for example, about 160 mm, and the length in the long side direction (X direction) including the folded portion 67. The length L2 is about 310 mm, for example.

  Here, in the first embodiment, the sealing plate 90 is fixed to the first plate member 70 fixed to the outer can 60 and the first plate member 70 as shown in FIGS. 1 to 3. And the second plate-like member 80. The first plate-like member 70 and the second plate-like member 80 are each composed of a metal plate, and the sealing plate 90 is formed by fixing these two plate-like members so as to face each other. Yes.

  The first plate-like member 70 constituting the sealing plate 90 is formed in a size capable of closing the opening 63 of the outer can 60. Specifically, as shown in FIG. 14, the first plate-like member 70 is formed in a substantially rectangular shape having a short side 70a and a long side 70b as viewed in a plan view. The length W3 in the short side direction (the length W3 in the Y direction) of the first plate-like member 70 is, for example, about 158 mm, and the length L3 in the long side direction (the length L3 in the X direction). ) Is configured to be about 308 mm, for example.

  In the first embodiment, as shown in FIG. 5, the first plate-like member 70 has a shorter side length W3 than a shorter side length W2 of the outer can 60 including the folded portion 67. Is formed so that the length L3 in the long side direction is shorter than the length L2 in the long side direction of the outer can 60 including the folded portion 67.

  In the first embodiment, as shown in FIGS. 3, 15, and 16, the first plate-like member 70 has a plurality of convex portions 71 that protrude toward the electrode group 50. The convex portion 71 is formed integrally with the first plate member 70 by, for example, pressing a metal plate. Further, as shown in FIGS. 15 and 17, each of the plurality of convex portions 71 has a bottom surface 72a and a side surface 72b on the opposite side (opposite surface) to the protruding side (electrode group 50 side). A recess 72 is formed. The recess 72 constitutes a space 73 for storing a replenishing non-aqueous electrolyte LQ (see FIGS. 22 and 24). The replenishing non-aqueous electrolyte LQ stored in the space 73 is preferably the same type as the non-aqueous electrolyte enclosed in the outer can 60 together with the electrode group 50.

  Further, as shown in FIG. 14, the first plate-like member 70 has five convex portions 71 (recessed portions 72), and each convex portion 71 extends in the long side direction (X direction). Is formed. Further, the five convex portions 71 are formed to be parallel to each other. Specifically, the convex portion 71 is formed such that the concave portion 72 on the side opposite to the protruding side has a width a11 of about 18 mm (width a11 in the short side direction) and about 200 mm. The length b11 (length b11 in the long side direction) is formed. Further, the convex portions 71 are arranged at equal intervals on the concave portion 72 side in the short side direction (Y direction) with an interval a12 of, for example, about 12 mm. For this reason, when the 1st plate-shaped member 70 is seen from the opposite side to the protrusion side, the said convex part 71 (concave part 72) is formed so that it may become a groove shape. Furthermore, the distance b12 from the short side 70a of the first plate-like member 70 to the concave portion 72 (convex portion 71) is, for example, about 54 mm, and the distance a13 from the long side 70b to the concave portion 72 (convex portion 71). Is configured to be approximately 10 mm, for example.

  Moreover, the said convex part 71 is comprised so that the depth of the recessed part 72 (space part 73) formed in the opposite side (opposite surface) to the protrusion side may be about 5 mm. In the convex portion 71, the opening width a1 of the concave portion 72 formed on the opposite side (opposite surface) to the protruding side (electrode group 50 side) (corresponding to the width a1 of the space portion 73 (the width a11 of the concave portion 72). )) (See FIG. 17) is preferably formed to be 5 mm or more.

  In the first embodiment, as shown in FIGS. 15 and 18, the nonaqueous electrolyte LQ for replenishment stored in the space 73 on the side surface 72 b of the recess 72 (projection 71) (see FIG. 22). ) To the electrode group 50 side is formed. The hole 74 is formed of, for example, a through hole having a diameter of 2 mm provided on the side surface 72 b on the one end side in the long side direction of the recess 72. Thus, as shown in FIG. 24, the hole 74 (leakage part) is configured not to contact the electrode group 50 accommodated in the outer can 60 in a state where the sealing plate 90 is fixed to the outer can 60. Has been.

Note that the hole 74 is preferably formed at a position close to the bottom surface 72 a of the recess 72. The specific shape of the hole 74 is not particularly limited, but is preferably formed so that the opening area of the hole 74 is smaller than 3 cm ² . When the opening area of the hole 74 is 3 cm ² or more, when the hole 74 is closed with the sealing member 75 described later, not only the amount of the resin material constituting the sealing member 75 is increased, but also the sealing strength is increased. It tends to decrease.

  Further, as shown in FIGS. 1 and 19, the second plate-like member 80 constituting the sealing plate 90 is formed in a substantially rectangular shape when seen in a plan view, and the concave portion 72 of the first plate-like member 70. It has a size capable of closing the opening. Specifically, the length L4 in the X direction of the second plate member 80 is configured to be about 306 mm, for example, and the length W4 in the Y direction of the second plate member 80 is set to about 156 mm, for example. It is configured.

  As shown in FIGS. 20 and 21, the second plate-like member 80 covers the opening portion of the recess 72 on the surface of the first plate-like member 70 opposite to the protruding side of the protrusion 71. It is fixed to. Specifically, the second plate-shaped member 80 is overlapped with the first plate-shaped member 70 so as to close the opening of the recess 72, and the outer periphery of the second plate-shaped member 80 is fillet welded by laser pulse welding. ing. Further, the second plate-like member 80 is overlap-welded at a portion surrounding the recess 72 (a portion indicated by a one-dot chain line P in FIGS. 5 and 21). Thereby, the opening part of the recessed part 72 of the 1st plate-shaped member 70 is in the state sealed by the 2nd plate-shaped member 80. FIG.

  In the first embodiment, as shown in FIGS. 20, 26, and 27, the corner 71 a (projection-side corner 71 a) of the convex portion 71 in the sealing plate 90 is rounded.

  The outer can 60 and the sealing plate 90 can be formed using, for example, a metal plate such as iron, stainless steel, or aluminum, or a steel plate obtained by applying nickel plating to iron. Since iron is an inexpensive material, it is preferable from the viewpoint of price, but in order to ensure long-term reliability, it is preferable to use a metal plate made of stainless steel, aluminum or the like, or a steel plate with nickel plated on iron. More preferred. The thickness of the metal plate can be, for example, about 0.4 mm to about 1.2 mm (for example, about 1.0 mm).

  Moreover, the 1st plate-shaped member 70 and the 2nd plate-shaped member 80 may be formed using the metal plate which has the same thickness, and may be formed using the metal plate which has different thickness.

  Further, as shown in FIG. 22, the nonaqueous electrolyte LQ for replenishment is injected into the space 73 of the sealing plate 90 through the hole 74, as shown in FIGS. 23 to 25. The hole 74 of the convex portion 71 is closed with a sealing member 75. The sealing member 75 is made of a resin material that swells with a non-aqueous electrolyte and can leak the non-aqueous electrolyte LQ in the space 73 to the electrode group 50 side after a predetermined time has elapsed. The hole 74 and the sealing member 75 form a leakage portion that causes the nonaqueous electrolyte LQ for replenishment to leak to the electrode group 50 side.

  The resin material constituting the sealing member 75 is preferably a material that can withstand an organic electrolyte, such as SBR (styrene butadiene rubber), EPDM (ethylene propylene diene monomer), butyl rubber, silicon rubber, and fluororesin-containing rubber. These resins are deteriorated by the nonaqueous electrolytic solution, and the replenishing nonaqueous electrolytic solution LQ can be leaked to the electrode group 50 side.

  Here, the resin is generally composed of a synthetic polymer, and it is known that the synthetic polymer usually deteriorates with age. Although there are many causes for the deterioration of the synthetic polymer, emphasis is placed on chemical resistance control in this embodiment. As the cause of deterioration, for example, oxygen, moisture, ultraviolet rays, heat, etc. in the atmosphere can be considered. However, when resin is used as the sealing member 75, it is installed in the metal outer container 100. The effects of oxygen, moisture, and ultraviolet light are reduced. In addition, regarding heat, if the resin is stable within the operating temperature range of a normal lithium ion secondary battery, the influence of deterioration due to chemical resistance is greater. Examples of chemical leakage due to general resin (adhesive) degradation include: contact surface leakage from the interface between the base material and the adhesive, and the penetration of the chemical into the polymer that constitutes the adhesive. There are known osmotic leakage, and breakage leakage in which a bond between polymers is cut and a physical interval is generated. In the present embodiment, the resin is caused to leak by being deteriorated by the electrolytic solution, and any one or two or more of the above-mentioned contact surface leakage, permeation leakage, and destruction leakage are generated in combination. Electrolyte leaks out. Further, the time for which the nonaqueous electrolyte LQ for replenishment leaks to the electrode group 50 side varies depending on the combination of the electrolyte type (for example, dielectric constant and SP value) and the dielectric constant and SP value of the resin. Considering the product life of the lithium ion secondary battery, the type of electrolyte, the material of the resin, the amount used, the surface area, etc. are set so that the product life is extended.

  The resin material constituting the sealing member 75 can be a resin material other than the above, but when selecting the resin material, an experiment for selecting a resin material that does not adversely affect the battery performance is performed. Preferably it is done. For example, it is preferable to perform battery performance evaluation using a non-aqueous electrolyte in which a resin material is immersed. By conducting such an experiment, a resin material that does not adversely affect battery performance can be selected. It is also preferable to conduct an experiment for controlling the leakage time of the non-aqueous electrolyte. For example, referring to JIS K6858 (“Testing method for chemical resistance of adhesives”) and JIS K7114 (“Testing method for determining the effect of immersion in plastics and liquid chemicals”), the resin material was immersed in a non-aqueous electrolyte. It is preferable that the weight change and the shape change rate are measured in advance, and the shape of the hole 74 of the convex portion 71 and the amount of the resin material constituting the sealing member 75 are determined. Then, based on the results of these experiments, the charge / discharge characteristics and the cycle characteristics are compared between the configuration with the non-aqueous electrolyte for replenishment and the configuration without it, and the sealing member 75 is configured. It is preferable to determine the type and amount of resin material used. The time until the non-aqueous electrolyte LQ in the space 73 leaks can be appropriately selected according to the use environment and battery specifications. In addition, the leakage form of a general resin material (sealing resin) is known to be contact surface leakage or permeation leakage, and the adhesive force between the sealing resin and the adherend and the substance in contact with the sealing resin Depends on affinity.

  As shown in FIG. 3, the electrode group 50 includes an outer can 60 such that the positive electrode 10 (see FIG. 1) and the negative electrode 20 (see FIG. 1) face the bottom surface portion 61 of the outer can 60. It is stored inside. The housed electrode group 50 includes a current collector exposed portion 11a (see FIGS. 8 and 9) of the positive electrode 10 and a current collector exposed portion 21a (see FIGS. 10 and 11) of the negative electrode 20, respectively. 5 (see FIG. 6), the electrode terminal 64 of the outer can 60 is electrically connected. The current collector lead 5 can be made of the same material as that of the current collector, but may be made of a different material.

  24 and 26, the opening 63 of the outer can 60 is sealed by the sealing plate 90 in which the replenishing nonaqueous electrolytic solution LQ is stored in the space 73 of the convex portion 71. . Specifically, the sealing plate 90 is arranged so that the convex portion 71 is on the electrode group 50 side, and the outer periphery of the first plate member 70 is fillet welded to the folded portion 67 of the outer can 60 by laser pulse welding. Has been. In addition, height H2 (refer FIG. 26) of the exterior container 100 sealed by the sealing board 90 is about 42 mm, for example.

  Further, the nonaqueous electrolytic solution is injected, for example, under reduced pressure from the liquid injection hole 65 after the opening 63 of the outer can 60 is sealed by the sealing plate 90. And after installing the metal ball | bowl 6 (refer FIG. 4) of the diameter substantially the same as the liquid injection hole 65 in the liquid injection hole 65, the liquid injection hole 65 is sealed by resistance welding, laser welding, etc.

  In the lithium ion secondary battery according to the first embodiment configured as described above, the non-aqueous electrolyte LQ for replenishment is stored in the space 73 of the sealing plate 90, and as time passes. Accordingly, the nonaqueous electrolyte LQ for replenishment is supplied to the electrode group 50 side through the hole 74 (leakage part) blocked by the sealing member 75. That is, the sealing member 75 is swollen by the nonaqueous electrolyte solution LQ for replenishment, and the nonaqueous electrolyte solution LQ leaks to the electrode group 50 side after a predetermined time has elapsed, so that the nonaqueous electrolyte solution LQ flows into the electrode group 50. Supplied. In this case, the hole portion 74 (leakage portion) is formed so as to be located above (directly above) the end portion of the electrode group 50, and the nonaqueous electrolyte solution LQ for replenishment is dropped onto the end portion of the electrode group 50. It is preferable to be configured to do so.

  In the lithium ion secondary battery according to the first embodiment, the convex portion 71 is provided on the sealing plate 90 as described above, whereby the rigidity of the sealing plate 90 can be increased by the convex portion 71. Thereby, when welding the sealing board 90 and the exterior can 60, it can suppress that the problem that distortion generate | occur | produces in the sealing board 90 with the heat | fever at the time of welding arises. Moreover, by comprising in this way, even when the thickness of the metal plate which comprises a sealing board is made small, the fall of rigidity can be suppressed. For this reason, a sealing board can be reduced in weight by forming a sealing board using a metal plate with small thickness.

  When the secondary battery is increased in size, the welding distance becomes longer, so that the sealing plate 90 is easily distorted during welding. On the other hand, by forming the convex portion 71 on the sealing plate 90 as described above, it is possible to prevent the sealing plate 90 from being distorted. For this reason, even when the battery is enlarged, the sealing plate 90 and the outer can 60 can be easily welded. Accordingly, the secondary battery can be easily increased in size, and thus a large-capacity lithium ion secondary battery can be easily obtained. Moreover, since the sealing plate 90 and the outer can 60 can be firmly fixed by suppressing the distortion of the sealing plate 90, the reliability and safety can be improved.

  In the first embodiment, a plurality of the convex portions 71 are formed on the first plate-like member 70 of the sealing plate 90, and each convex portion 71 is formed so as to extend in the long side direction. When welding a long side portion having a long length, the generation of distortion of the sealing plate 90 due to heat during welding can be further suppressed. For this reason, since the sealing board 90 and the exterior can 60 can be firmly fixed easily, the pressure | voltage resistance of the exterior container 100 can be raised. Thereby, the sealing plate 90 can be easily 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 66. Therefore, even when the battery internal pressure increases, the outer container 100 can be prevented from opening before the safety valve 66 operates. As a result, by releasing the battery internal pressure with the safety valve 66, it is possible to avoid dangers such as battery explosion.

  Further, in the first embodiment, the convex portion 71 is formed so as to protrude toward the electrode group 50 and to have a space portion 73 on the surface side opposite to the electrode group 50 side (opposite side from the protruding side). As a result, the nonaqueous electrolyte LQ for replenishment can be stored in the space 73. And by forming the hole 74 (leakage part) in the area | region of the convex part 71, the nonaqueous electrolyte LQ stored in the space part 73 is this electrode part 50 side via this hole 74 (leakage part). Can be supplied to. As a result, a new non-aqueous electrolyte LQ can be supplied to the electrode group 50. Therefore, even when the discharge capacity decreases as the charge / discharge cycle progresses, the rechargeable non-aqueous electrolyte LQ is supplied to supply the electrode group 50. Discharge cycle characteristics can be improved.

  Here, when the non-aqueous electrolyte is re-injected through the injection hole 65 or the like, the environment for re-injection needs to be low humidity, so equipment such as a glove box whose humidity is controlled is necessary. Become. And since a large-sized lithium ion secondary battery is difficult to bring in facilities, such as a glove box, the large-sized battery produces the problem that the maintainability at the time of re-injection falls.

  However, in the first embodiment, by configuring as described above, a new non-aqueous electrolyte can be supplied to the electrode group 50 without being brought into equipment such as a glove box. Thereby, maintenance-free can be achieved by a simple method and a long life can be achieved. That is, the battery life can be extended by a maintenance-free method only by grasping the relationship of the nonaqueous electrolyte leakage to the sealing member 75 (resin material). Therefore, a large-sized secondary battery using a flat rectangular can that can be used for a long period of time can be obtained by a maintenance-free method.

  Moreover, in 1st Embodiment, it is easy by sealing the hole 74 of the convex part 71 with the sealing member 75 which can leak the nonaqueous electrolyte LQ of the space part 73 to the electrode group 50 side. In addition, the non-aqueous electrolyte LQ stored in the space 73 can be supplied to the electrode group 50 side. Thereby, charge / discharge cycle characteristics can be easily improved. Further, by supplying the non-aqueous electrolyte LQ stored in the space 73 to the electrode group 50 side, the non-aqueous electrolyte can be prevented from withering, so that the non-aqueous electrolyte can be easily withered. It is possible to suppress the deterioration of battery performance due to.

  In the first embodiment, the sealing member 75 is swollen by the nonaqueous electrolyte, and the resin material that can leak the nonaqueous electrolyte LQ in the space 73 to the electrode group 50 side after a predetermined time has elapsed. The non-aqueous electrolyte LQ stored in the space 73 can be easily supplied to the electrode group 50 side.

  Moreover, in 1st Embodiment, while forming the several convex part 71 in the sealing board 90 (1st plate-shaped member 70), the nonaqueous electrolyte LQ for replenishment is supplied to each of the several convex part 71. FIG. By forming the hole portion 74 for this purpose, it is possible to store the nonaqueous electrolyte solution LQ for replenishment in each of the space portions 73 provided by forming the convex portions 71. In addition, the non-aqueous electrolyte LQ stored in each of the space portions 73 can be supplied to the electrode group 50 side through the hole portions 74 provided in the respective convex portions 71. For this reason, since the quantity of the nonaqueous electrolyte LQ which can be stored in the space part 73 can be increased, the nonaqueous electrolyte LQ can be supplied to the electrode group 50 side over a long period of time. Thereby, the charge / discharge cycle characteristics can be improved more easily, and the life of the battery can be extended. Moreover, the rigidity of the sealing board 90 can be improved more by forming the some convex part 71 in the sealing board 90 (1st plate-shaped member 70).

  Moreover, in 1st Embodiment, when the said convex part 71 is seen from the opposite side to the electrode group 50, it is comprised so that it may become a groove shape, By this non-aqueous electrolyte LQ for replenishment inside this groove | channel Can be stored, and the rigidity of the sealing plate 90 (exterior container 100) can be easily increased.

  Moreover, in 1st Embodiment, the hole 74 (leakage part) and the electrode group 50 contact by forming the hole 74 (leakage part) of the convex part 71 in the position which does not contact the electrode group 50. As a result, it is possible to suppress the inconvenience that the electrode group 50 is damaged. Thereby, generation | occurrence | production of the internal short circuit resulting from damage of the electrode group 50 can be suppressed. As a result, it is possible to suppress deterioration of charge / discharge cycle characteristics and reliability due to occurrence of an internal short circuit. If an internal short circuit occurs during battery assembly, the yield may be reduced. Therefore, the yield improvement effect can also be obtained by suppressing the occurrence of an internal short circuit.

  In the first embodiment, by rounding the corner 71 a of the convex 71, damage to the electrode group 50 due to contact between the convex 71 and the electrode group 50 can be effectively suppressed. Thereby, generation | occurrence | production of an internal short circuit can be suppressed effectively.

  In the first embodiment, if the opening width a1 of the concave portion 72 (the width a1 of the space portion 73) is 5 mm or more, it is easy to suppress damage to the electrode group 50 due to contact between the convex portion 71 and the electrode group 50. can do. Moreover, if comprised in this way, it can suppress that the problem that the volume of the space part 73 becomes too small resulting from the width a1 of the space part 73 becoming too small arises. As a result, it is possible to suppress the inconvenience that the amount of the non-aqueous electrolyte LQ stored in the space 73 becomes too small to make it difficult to recover the discharge capacity.

  Furthermore, in the first embodiment, the surface of the outer can 60 that has the largest area is the bottom surface portion 61, and the opening 63 for accommodating the electrode group 50 is provided on the side facing the bottom surface portion 61. The electrode (electrode group 50) can be easily accommodated in the container. Thereby, manufacture of a high capacity | capacitance secondary battery can be made easy. Further, by configuring the outer can 60 as described above, the amount of deep drawing can be reduced even when the area of the electrode is increased. For this reason, while being able to improve the freedom degree of selection of the material used for the armored can 60, an armored can can be produced, without using several expensive metal mold | dies.

  The lithium ion secondary battery according to the first embodiment configured as described above can be suitably used as a stationary power storage battery 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). The lithium ion secondary battery according to the first embodiment is suitable for a large capacity storage battery having a unit cell capacity of 10 Ah or more, which is difficult to bring into a facility such as a glove box.

(Modification of the first embodiment)
FIG. 28 is a cross-sectional view of a lithium ion secondary battery according to a modification of the first embodiment. FIG. 29 is an enlarged cross-sectional view of a portion D3 in FIG. Next, with reference to FIG. 28 and FIG. 29, the lithium ion secondary battery by the modification of 1st Embodiment is demonstrated.

  In the modification of the first embodiment, as shown in FIGS. 28 and 29, chamfering is performed on the corner 71 a (projecting side corner 71 a) of the convex portion 71 in the sealing plate 90. That is, in the modification of the first embodiment, the corner 71a of the convex portion 71 (the corner 71a on the protruding side) is chamfered. Accordingly, it is possible to effectively suppress damage to the electrode group 50 due to contact between the convex portion 71 and the electrode group 50. Therefore, by comprising in this way, generation | occurrence | production of the internal short circuit resulting from damage of the electrode group 50 can be suppressed effectively. As a result, it is possible to suppress deterioration of charge / discharge cycle characteristics and reliability due to occurrence of an internal short circuit. The chamfering of the corner portion 71a can be performed by, for example, shaving with a grinder or an end mill.

  Other configurations according to the modified example of the first embodiment are the same as those of the first embodiment. In addition, other effects obtained by the modification of the first embodiment are the same as those of the first embodiment.

(Second Embodiment)
FIG. 30 is an exploded perspective view of a lithium ion secondary battery according to the second embodiment of the present invention. FIG. 31 is an overall perspective view of a lithium ion secondary battery according to a second embodiment of the present invention. 32 to 34 are views for explaining a lithium ion secondary battery according to a second embodiment of the present invention. FIG. 32 shows a cross section taken along line A4-A4 of FIG. Next, with reference to FIGS. 30-34, the lithium ion secondary battery by 2nd Embodiment of this invention is demonstrated. In addition, in each figure, the same code | symbol is attached | subjected to a corresponding component, and the overlapping description is abbreviate | omitted.

  In the lithium ion secondary battery according to the second embodiment, as shown in FIGS. 30 to 32, in the configuration of the first embodiment, the sealing plate 90 has a convex portion 271 having a shape different from that of the first embodiment. Is formed. Specifically, the sealing plate 90 includes a first plate member 70 and a second plate member 80 as in the first embodiment, and the first plate member 70 is relatively large. One convex portion 271 having an area is formed. As shown in FIGS. 32 to 34, the convex portion 271 protrudes toward the electrode group 50, and replenishes nonaqueous electrolyte on the opposite side (opposite surface) to the protruding side (electrode group 50 side). It has a space 273 (recess 272) for storing LQ. In addition, the recessed part 272 is comprised including the bottom face 272a and the side surface 272b similarly to the said 1st Embodiment.

  As shown in FIG. 33, the convex portion 271 (concave portion 272) of the sealing plate 90 (first plate-like member 70) is formed in a substantially rectangular shape (substantially rectangular shape) when seen in a plan view. Further, the convex portion 271 is formed on the concave portion 272 side so that the length b2 in the long side direction (X direction) is about 200 mm, for example, and the width a2 in the short side direction (Y direction) is For example, it is formed to be about 130 mm. Furthermore, the convex portion 271 is formed so that the depth of the concave portion 272 formed on the opposite side (opposite surface) to the protruding side is, for example, about 5 mm, as in the first embodiment.

  Other configurations of the second embodiment are the same as those of the first embodiment. The effect of the second embodiment is the same as that of the first embodiment.

  In addition, the corner | angular part 271a (projection side corner | angular part 271a) (refer FIG. 32) of the convex part 271 in the sealing board 90 (1st plate-shaped member 70) is made into the rounded corner shape like the said 1st Embodiment. Alternatively, as in the modified example of the first embodiment, a chamfered shape may be used.

(Third embodiment)
FIG. 35 is a plan view of the first plate-like member constituting the sealing plate of the lithium ion secondary battery according to the third embodiment of the present invention. FIG. 36 is a perspective view of a first plate-like member constituting the sealing plate of the lithium ion secondary battery according to the third embodiment of the present invention. FIG. 35 shows a plan view of the first plate-like member as viewed from the lower side (projecting side of the convex portion), and FIG. 36 shows the first plate-like member on the upper side (opposite side from the projecting side of the convex portion). The perspective view seen from FIG. Next, with reference to FIG. 24, FIG. 35 and FIG. 36, a lithium ion secondary battery according to a third embodiment of the present invention will be described. In addition, in 3rd Embodiment, since structures other than the convex part of a sealing board are the same as that of the said 1st Embodiment, the description is abbreviate | omitted.

  In the third embodiment, as shown in FIGS. 35 and 36, two convex portions 371 are formed on the first plate-like member 70 of the sealing plate 90. These two convex portions 371 are formed so as to extend in a direction intersecting with the long side direction (X direction), and are formed in a substantially “<” shape by being bent in the middle thereof. Further, the two convex portions 371 are configured to be a target with respect to, for example, a one-dot chain line Q1 (for example, a center line in the short side direction (Y direction)) drawn in parallel with the long side 70b. As shown in FIG. The convex portion 371 is arranged so that the substantially rhombic diagonal line is parallel to the long side 70b and the short side 70a, respectively.

  As shown in FIG. 36, the formation of the convex portion 371 forms a concave portion 372 on the opposite side (opposite surface) to the protruding side of the first plate-like member 70. The recess 372 constitutes a space 373 for storing a non-aqueous electrolyte LQ for replenishment (see FIG. 24). Further, the first plate member 70 is configured such that the concave portion 372 has a groove shape when the first plate member 70 is viewed from the side opposite to the protruding side. As shown in FIG. 35, the opening width a3 of the recess 372 (the width a3 of the space 373) is configured to be about 8 mm, for example.

  The other structure of the sealing board 90 in 3rd Embodiment is the same as that of the said 1st Embodiment. The effects of the third embodiment are the same as those of the first embodiment.

  Further, the corner portion 371a (projection side corner portion 371a) of the convex portion 371 in the sealing plate 90 (first plate-like member 70) may have a rounded corner shape as in the first embodiment. You may make it a chamfering shape like the modification of 1st Embodiment.

(Fourth embodiment)
FIG. 37 is a plan view of a first plate-like member constituting the sealing plate of the lithium ion secondary battery according to the fourth embodiment of the present invention. FIG. 38 is a perspective view of the first plate-like member constituting the sealing plate of the lithium ion secondary battery according to the fourth embodiment of the present invention. FIG. 37 shows a plan view of the first plate-like member as viewed from the lower side (projecting side of the convex portion), and FIG. 38 shows the first plate-like member on the upper side (opposite side from the projecting side of the convex portion). The perspective view seen from FIG. Next, with reference to FIGS. 24, 37, and 38, a lithium ion secondary battery according to a fourth embodiment of the invention will be described. In addition, in 4th Embodiment, since structures other than the convex part of a sealing board are the same as that of the said 1st Embodiment, the description is abbreviate | omitted.

  In the fourth embodiment, as shown in FIGS. 37 and 38, a convex portion 471 having a substantially similar shape to the convex portion 371 is further formed in the configuration of the third embodiment. In other words, the fourth embodiment has a configuration in which more convex portions (convex portions 371 and 372) are formed on the first plate-like member 70 than in the third embodiment. Thus, in 4th Embodiment, the rigidity of the sealing board 90 can be improved more by increasing the number of the convex parts formed in the sealing board 90 (1st plate-shaped member 70). In addition, since the supplementary non-aqueous electrolyte LQ (see FIG. 24) can be stored in each of the space portions 373 and 473 provided by forming the convex portions 371 and 471, the configuration of the third embodiment Compared to the above, charge / discharge cycle characteristics can be further improved.

  In the convex portion 471 having a substantially similar shape, the width of the space portion 473 and the depth of the space portion 473 are formed the same as the convex portion 371.

  The other structure of the sealing board 90 in 4th Embodiment is the same as that of the said 1st and 3rd embodiment. The effects of the fourth embodiment are the same as those of the first and third embodiments.

(Fifth embodiment)
FIG. 39 is a plan view of a first plate-like member constituting the sealing plate of the lithium ion secondary battery according to the fifth embodiment of the present invention. FIG. 40 is a perspective view of a first plate-like member constituting the sealing plate of the lithium ion secondary battery according to the fifth embodiment of the present invention. 39 shows a plan view of the first plate-like member as viewed from the lower side (projecting side of the convex portion), and FIG. 40 shows the first plate-like member on the upper side (opposite side from the projecting side of the convex portion). The perspective view seen from FIG. Next, with reference to FIGS. 24, 39 and 40, a lithium ion secondary battery according to a fifth embodiment of the invention will be described. In addition, in 5th Embodiment, since structures other than the convex part of a sealing board are the same as that of the said 1st Embodiment, the description is abbreviate | omitted.

  In the fifth embodiment, as shown in FIGS. 39 and 40, one convex portion 571 is formed on the first plate-like member 70 of the sealing plate 90. The convex portion 571 is formed so that each portion thereof extends in a direction intersecting the long side direction (X direction), and is formed in an annular shape having a substantially rhombus shape when seen in a plan view. The convex portion 571 is arranged so that the substantially rhombic diagonal line is parallel to the long side 70b and the short side 70a, respectively.

  In addition, as shown in FIG. 40, a concave portion 572 is formed on the opposite side (opposite surface) to the protruding side of the first plate-like member 70 by forming the convex portion 571. The concave portion 572 constitutes a space portion 573 for storing the nonaqueous electrolyte LQ for replenishment (see FIG. 24). Moreover, when the 1st plate-shaped member 70 is seen from the opposite side to a protrusion side, the said recessed part 572 is comprised so that it may become groove shape. As shown in FIG. 39, the opening width a5 of the recess 572 (the width a5 of the space portion 573) is, for example, about 8 mm.

  The other structure of the sealing board 90 in 5th Embodiment is the same as that of the said 1st Embodiment. The effects of the fifth embodiment are the same as those of the first embodiment.

(Sixth embodiment)
FIG. 41 is a plan view of a first plate-like member constituting the sealing plate of the lithium ion secondary battery according to the sixth embodiment of the present invention. FIG. 42 is a perspective view of a first plate member constituting the sealing plate of the lithium ion secondary battery according to the sixth embodiment of the present invention. 41 shows a plan view of the first plate-like member as viewed from the lower side (projecting side of the convex portion), and FIG. 42 shows the first plate-like member on the upper side (opposite side from the projecting side of the convex portion). The perspective view seen from FIG. Next, with reference to FIG. 24, FIG. 41 and FIG. 42, a lithium ion secondary battery according to a sixth embodiment of the present invention will be described. In addition, in 6th Embodiment, since structures other than the convex part of a sealing board are the same as that of the said 1st Embodiment, the description is abbreviate | omitted.

  In the sixth embodiment, as shown in FIGS. 41 and 42, in the configuration of the fifth embodiment, a convex portion 671 having a shape substantially similar to the convex portion 571 is further formed. That is, in the sixth embodiment, compared to the fifth embodiment, the first plate member 70 has a configuration in which more convex portions (convex portions 571 and 671) are formed. Thus, in 6th Embodiment, the rigidity of the sealing board 90 can be improved more by increasing the number of the convex parts formed in the sealing board 90 (1st plate-shaped member 70). In addition, since the supplementary non-aqueous electrolyte LQ (see FIG. 24) can be stored in each of the space portions 573 and 673 provided by forming the convex portions 571 and 671, the configuration of the fifth embodiment Compared to the above, charge / discharge cycle characteristics can be further improved.

  In the convex portion 671 having a substantially similar shape, the width of the space portion 673 and the depth of the space portion 673 are formed to be the same as those of the convex portion 571.

  Other configurations of the sealing plate 90 in the sixth embodiment are the same as those in the first and fifth embodiments. The effects of the sixth embodiment are the same as those of the first and fifth embodiments.

(Seventh embodiment)
FIG. 43 is a plan view of a first plate-like member constituting the sealing plate of the lithium ion secondary battery according to the seventh embodiment of the present invention. FIG. 44 is a perspective view of a first plate-like member constituting the sealing plate of the lithium ion secondary battery according to the seventh embodiment of the present invention. 43 shows a plan view of the first plate-like member as viewed from the lower side (projecting side of the convex portion), and FIG. 44 shows the first plate-like member on the upper side (opposite side from the projecting side of the convex portion). The perspective view seen from FIG. Next, a lithium ion secondary battery according to a seventh embodiment of the invention will be described with reference to FIGS. In addition, in 7th Embodiment, since structures other than the convex part of a sealing board are the same as that of the said 1st Embodiment, the description is abbreviate | omitted.

  In the seventh embodiment, as shown in FIGS. 43 and 44, four convex portions 771 are formed on the first plate-like member 70 of the sealing plate 90. These four convex portions 771 are formed so as to extend in a direction intersecting the long side direction (X direction), and are formed so as to form a substantially rhombus shape as a whole. The four convex portions 771 are, for example, a one-dot chain line Q1 (for example, a center line in the short side direction (Y direction)) drawn in parallel with the long side 70b and a one-dot chain line Q2 (for example, drawn in parallel with the short side 70a). , A center line in the long side direction (X direction).

  As shown in FIG. 44, the formation of the convex portion 771 forms a concave portion 772 on the opposite side (opposite surface) to the protruding side of the first plate member 70. The concave portion 772 constitutes a space portion 773 for storing a replenishing non-aqueous electrolyte LQ (see FIG. 24). Moreover, when the 1st plate-shaped member 70 is seen from the opposite side to a protrusion side, the said recessed part 772 is comprised so that it may become groove shape. As shown in FIG. 43, the opening width a7 of the concave portion 772 (the width a7 of the space portion 773) is, for example, about 8 mm, as in the third to sixth embodiments.

  The other structure of the sealing board 90 in 7th Embodiment is the same as that of the said 1st Embodiment. The effects of the seventh embodiment are the same as those of the first embodiment.

(Eighth embodiment)
FIG. 45 is a plan view of a first plate-like member constituting the sealing plate of the lithium ion secondary battery according to the eighth embodiment of the present invention. FIG. 46 is a perspective view of a first plate member constituting the sealing plate of the lithium ion secondary battery according to the eighth embodiment of the present invention. 45 shows a plan view of the first plate-like member as viewed from the lower side (projection side of the convex portion), and FIG. 46 shows the first plate-like member on the upper side (opposite side from the projection side of the convex portion). The perspective view seen from FIG. Next, with reference to FIGS. 24, 45 and 46, a lithium ion secondary battery according to an eighth embodiment of the invention will be described. Note that in the eighth embodiment, the configuration other than the convex portions of the sealing plate is the same as that of the first embodiment, and a description thereof will be omitted.

  In the eighth embodiment, as shown in FIGS. 45 and 46, in the configuration of the seventh embodiment, a convex portion 871 having a shape substantially similar to the convex portion 771 is further formed. That is, the eighth embodiment has a configuration in which more convex portions (convex portions 771 and 871) are formed on the first plate-like member 70 than in the seventh embodiment. Thus, in 8th Embodiment, the rigidity of the sealing board 90 can be improved more by increasing the number of the convex parts formed in the sealing board 90 (1st plate-shaped member 70). In addition, since the supplementary non-aqueous electrolyte LQ (see FIG. 24) can be stored in each of the space portions 773 and 873 provided by forming the convex portions 771 and 871, the configuration of the seventh embodiment Compared to the above, charge / discharge cycle characteristics can be further improved.

  In the convex portion 871 having a substantially similar shape, the width of the space portion 873 and the depth of the space portion 873 are the same as those of the convex portion 771.

  The other structure of the sealing board 90 in 8th Embodiment is the same as that of the said 1st and 5th Embodiment. The effects of the eighth embodiment are the same as those of the first and fifth embodiments.

(Ninth embodiment)
FIG. 47 is a plan view of a first plate-like member constituting the sealing plate of the lithium ion secondary battery according to the ninth embodiment of the present invention. FIG. 48 is a perspective view of a first plate member constituting the sealing plate of the lithium ion secondary battery according to the ninth embodiment of the present invention. 47 shows a plan view of the first plate-like member as viewed from the lower side (projection side of the convex portion), and FIG. 48 shows the first plate-like member on the upper side (opposite side from the projection side of the convex portion). The perspective view seen from FIG. Next, a lithium ion secondary battery according to a ninth embodiment of the invention will be described with reference to FIGS. Note that in the ninth embodiment, the configuration other than the convex portions of the sealing plate is the same as that of the first embodiment, and a description thereof will be omitted.

  In the ninth embodiment, as shown in FIGS. 47 and 48, the first plate member 70 of the sealing plate 90 is formed with two convex portions 971 extending in the long side direction (X direction). These two convex portions 971 have the same shape as the convex portion 71 (see FIG. 14) of the first embodiment, and are arranged so as to be parallel to each other. One of the two convex portions 971 is arranged on one end side (Y1 side) in the short side direction (Y direction), and the other of the two convex portions 971 is in the short side direction (Y direction). It is arranged on the other end side (Y2 side). The interval a9 between the convex portions 971 is about 102 mm, for example.

  Other configurations of the sealing plate 90 in the ninth embodiment are the same as those in the first embodiment. The effects of the ninth embodiment are the same as those of the first embodiment.

(10th Embodiment)
FIG. 49 is a plan view of a first plate-like member constituting the sealing plate of the lithium ion secondary battery according to the tenth embodiment of the present invention. FIG. 50 is a perspective view of a first plate-like member constituting the sealing plate of the lithium ion secondary battery according to the tenth embodiment of the present invention. 49 shows a plan view of the first plate-like member as viewed from the lower side (projecting side of the convex portion), and FIG. 50 shows the first plate-like member on the upper side (opposite side from the projecting side of the convex portion). The perspective view seen from FIG. Next, with reference to FIGS. 14, 49 and 50, a lithium ion secondary battery according to a tenth embodiment of the invention will be described. In the tenth embodiment, the configuration other than the convex portion of the sealing plate is the same as that of the first embodiment, and a description thereof will be omitted.

  In the tenth embodiment, as shown in FIGS. 49 and 50, five convex portions 1071 extending in the long side direction (X direction) are formed on the first plate-like member 70 of the sealing plate 90. These five convex portions 1071 are formed so that the opening width of the concave portion (the width of the convex portion) is smaller than the convex portion 71 (see FIG. 14) of the first embodiment. Specifically, the width a10 on the concave portion 1072 side of the convex portion 1071 is configured to be about 6 mm, for example.

  Other configurations of the sealing plate 90 in the tenth embodiment are the same as those in the first embodiment. The effects of the tenth embodiment are the same as those of the first embodiment.

(Eleventh embodiment)
FIG. 51 is a plan view of a first plate-like member constituting the sealing plate of the lithium ion secondary battery according to the eleventh embodiment of the present invention. FIG. 52 is a perspective view of a first plate-like member constituting the sealing plate of the lithium ion secondary battery according to the eleventh embodiment of the present invention. 51 shows a plan view of the first plate-like member as seen from the lower side (projecting side of the convex portion), and FIG. 52 shows the first plate-like member on the upper side (opposite side from the projecting side of the convex portion). The perspective view seen from FIG. Next, with reference to FIGS. 51 and 52, a lithium ion secondary battery according to an eleventh embodiment of the present invention will be described. In the eleventh embodiment, the configuration other than the convex portion of the sealing plate is the same as that of the first embodiment, and a description thereof will be omitted.

  In the eleventh embodiment, as shown in FIGS. 51 and 52, in the configuration of the tenth embodiment, similar convex portions 1071 are further formed between adjacent convex portions 1071. Therefore, in the eleventh embodiment, the nine convex portions 1071 are formed to extend in the long side direction (X direction). The nine convex portions 1071 are arranged at equal intervals in the short side direction (Y direction).

  Other configurations of the sealing plate 90 in the eleventh embodiment are the same as those in the first and FIG. 10 embodiments. The effects of the eleventh embodiment are the same as those of the first embodiment.

(Twelfth embodiment)
53 and 54 are plan views of the first plate-like member constituting the sealing plate of the lithium ion secondary battery according to the twelfth embodiment of the present invention. FIG. 55 is a perspective view of the first plate-like member constituting the sealing plate of the lithium ion secondary battery according to the twelfth embodiment of the present invention. 53 shows a plan view of the first plate-like member as viewed from the lower side (projection side of the convex portion), and FIGS. 54 and 55 respectively show the first plate-like member on the upper side (projection of the convex portion). The plan view and perspective view seen from the side opposite to the side) are shown. Next, a lithium ion secondary battery according to a twelfth embodiment of the present invention will be described with reference to FIGS. Note that in the twelfth embodiment, the configuration other than the convex portions of the sealing plate is the same as that of the first embodiment, and a description thereof will be omitted.

  In the twelfth embodiment, as shown in FIGS. 53 to 55, the first plate member 70 of the sealing plate 90 is formed with three convex portions 1271 extending in parallel to each other in the long side direction (X direction). Yes. As shown in FIG. 54, these three convex portions 1271 are formed such that a concave portion 1272 opposite to the protruding side has a width a121 of about 30 mm. Note that the length b121 in the long side direction (X direction) is, for example, about 200 mm, as in the first embodiment.

  The convex portions 1271 are arranged at equal intervals in the short side direction (Y direction), for example, with an interval a122 of about 24 mm on the concave portion 1272 side. For this reason, when the 1st plate-shaped member 70 is seen from the opposite side to a protrusion side, the said convex part 1271 (concave part 1272) is formed so that it may become a groove shape. Furthermore, the distance b122 from the short side 70a of the first plate-like member 70 to the recess 1272 is configured to be, for example, about 10 mm, and the distance a123 from the long side 70b of the first plate-like member 70 to the recess 1272 is, for example, It is configured to be about 10 mm.

  Further, the convex portion 1271 is configured such that the depth of a concave portion 1272 (space portion 1273) formed on the opposite side (opposite surface) to the protruding side is, for example, about 5 mm.

  Other configurations of the sealing plate 90 in the twelfth embodiment are the same as those in the first embodiment. The effect of the twelfth embodiment is the same as that of the first embodiment.

  Next, an experiment conducted for confirming the effect of the embodiment will be described.

  In this experiment, in order to confirm the effect of improving the rigidity of the sealing plate by the formation of the convex portion, a pressure resistance test of the outer container was performed. Moreover, in order to confirm the effect of improving battery characteristics, a charge / discharge cycle test was also performed.

  The pressure resistance test was performed by preparing an outer container in which the electrode group and the non-aqueous electrolyte were not sealed, and applying an internal pressure to the outer container with nitrogen gas. Moreover, the exterior container which formed the convex part in the sealing board (1st plate-shaped member) was made into the Example, and the exterior container which has not formed the convex part in the sealing board (1st plate-shaped member) was made into the comparative example. The example and the comparative example were made to be the same except for the presence or absence of the convex portion of the sealing plate (first plate-like member).

  The outer can was formed so that the length in the short side direction was 150 mm, the length in the long side direction was 300 mm, and the depth was 40 mm in both the examples and the comparative examples. The width of the folded portion in the outer can was 5 mm. The sealing plate was formed by laminating the first plate member and the second plate member by laser pulse welding. The first plate member of the sealing plate is formed so that the length in the long side direction is 308 mm and the length in the short side direction is 158 mm. The second plate member of the sealing plate is formed in the long side direction. The length was 306 mm and the length in the short side direction was 156 mm. A stainless steel plate (SUS304) having a thickness of about 1.0 mm was used for the outer can and the sealing plate (first plate-like member, second plate-like member).

  Moreover, five types of exterior containers with different shapes of the convex portions of the sealing plate were produced as the exterior containers according to the examples, and Examples 1 to 5 were used respectively.

<Example 1>
In Example 1, as shown in FIG. 56, the convex part 271 similar to the said 2nd Embodiment was formed in the sealing board 90 (1st plate-shaped member 70).

<Example 2>
In Example 2, as shown in FIG. 57, the convex part 71 similar to the said 1st Embodiment was formed in the sealing board 90 (1st plate-shaped member 70).

<Example 3>
In Example 3, as shown in FIG. 58, the convex part 371 similar to the said 3rd Embodiment was formed in the sealing board 90 (1st plate-shaped member 70).

<Example 4>
In Example 4, as shown in FIG. 59, the convex part 571 similar to the said 5th Embodiment was formed in the sealing board 90 (1st plate-shaped member 70).

<Example 5>
In Example 5, as shown in FIG. 60, the convex part 771 similar to the said 7th Embodiment was formed in the sealing board 90 (1st plate-shaped member 70).

<Comparative example>
In the comparative example, as shown in FIG. 61, the sealing plate 90 (the first plate-like member 70) has a configuration in which no convex portion is formed. In addition, also in the comparative example, the sealing board was comprised by bonding together the 1st plate-shaped member and the 2nd plate-shaped member similarly to the said Examples 1-5.

  Moreover, the electrode terminal part (a positive electrode terminal part and a negative electrode terminal part) and the safety valve part in the outer can were sealed with laser so that no leakage occurred from this part. And the exterior container by Examples 1-5 and a comparative example was produced by carrying out fillet welding of the sealing board to this exterior can by laser pulse welding. In addition, the sealing plate by Examples 1-5 and a comparative example was produced by carrying out fillet welding of the 2nd plate-shaped member to each 1st plate-shaped member. The welding conditions between the outer can and the sealing plate and the welding conditions between the first plate member and the second plate member in Examples 1 to 5 and the comparative example were all the same. However, in the examples (Examples 2 to 5), welding of the first plate-like member and the second plate-like member is performed by overlap welding in addition to fillet welding. Furthermore, in an Example (Examples 1-5), it is set as the structure (without sealing stopper) which provided the hole part in the convex part.

  In this manner, five exterior containers according to Examples 1 to 5 and the comparative example were produced, and a pressure resistance test was performed using the produced exterior containers. Specifically, pressure was applied by injecting nitrogen gas from a liquid injection hole for injecting a non-aqueous electrolyte, and the pressure when nitrogen gas leaked from the welded part between the outer can and the sealing plate was measured. . And the pressure at this time was made into the pressure at the time of destruction. The results are shown in Table 1. The leak position was confirmed in water. Moreover, the result of Table 1 has shown the average value of each 5 pieces which performed the pressure | voltage resistant test.

As shown in Table 1 above, in Examples 1 to 5 in which convex portions are formed on the sealing plate (first plate-like member), the pressure at breakage is higher than in the comparative example in which the convex portions are not formed. was gotten. Specifically, the pressure at break according to the comparative example was 5.6 kg / cm ² , whereas the pressure at break according to the example was 6.2 kg / cm ^{2 in} Example 1 and Example 2 in, 8.4 kg / cm ^2, in example 3, 7.7 kg / cm ^2, in example 4, 7.5 kg / cm ^2, in example 5, was 7.1 kg / cm ^2. That is, in Examples 1-5, the pressure at the time of destruction became about 10%-50% higher than the comparative example.

  From the above results, it can be said that in Examples 1 to 5, the sealing plate is appropriately welded as compared with the comparative example, and the distortion of the sealing plate during welding is suppressed. Thereby, it turns out that the rigidity of a sealing board can be improved by forming a convex part in a sealing board.

  In Examples 1 to 5, Example 2 in which a plurality of convex portions are formed so as to extend in the longitudinal direction has the highest pressure at break, and Example 1 in which one convex portion having a relatively large area is formed is the most. The result was low pressure at break. Further, in Examples 3 to 5 in which the convex portions (extending in the direction intersecting the longitudinal direction) are formed so as to have a substantially rhombus shape, the pressures at the time of destruction are almost the same value. The reason why such a result is obtained is considered to be influenced by the number and arrangement of convex portions. In addition, from the results of Table 1, it is preferable to form the convex portion so as to extend in the longitudinal direction or the direction intersecting the longitudinal direction, rather than forming one relatively large area convex portion. From this point of view, it is considered preferable.

  Moreover, the pressure at the time of destruction should just be higher than the operating pressure of a safety valve, but it is preferable to use an exterior container with a higher pressure at the time of destruction in consideration of unforeseen circumstances such as when the safety valve does not operate.

  Next, the charge / discharge cycle test will be described.

  In this charge / discharge cycle test, using the same outer container as the outer container used in the pressure resistance test (the outer container according to Examples 1 to 5 and the comparative example), the lithium ion secondary according to Examples 1 to 5 and the comparative example. A battery was produced. However, the outer can is provided with an electrode terminal and a safety valve. And characteristic evaluation was performed using each produced lithium ion secondary battery. The production of the electrode group, the production of the non-aqueous electrolyte, and the assembly of the secondary battery were performed as follows.

<Common to Examples 1 to 5 and Comparative Example>
[Production of positive electrode]
First, 90 parts by weight of LiFePO _{4 as} an active material, 50 parts by weight of acetylene black as a conductive material, and 5 parts by weight of polyvinylidene fluoride as a binder were mixed, and N-methyl-2-pyrrolidone was appropriately added and dispersed. Thus, the positive electrode mixture slurry was prepared. Next, this 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 200 μm. Finally, the positive electrode (positive electrode plate) of Examples 1 to 5 and the comparative example was manufactured by cutting into a desired size. The size of the positive electrode active material layer was 140 mm long and 235 mm wide, and the positive electrode (positive electrode current collector) was 140 mm long and 250 mm wide.

[Production of negative electrode]
After 90 parts by weight of natural graphite (Chinese natural graphite) and 10 parts by weight of polyvinylidene fluoride were mixed, N-methyl-2-pyrrolidone was appropriately added and dispersed to prepare a negative electrode mixture slurry. Next, this negative electrode mixture slurry was uniformly applied to both sides of a copper current collector (negative electrode current collector) having a thickness of 16 μm, dried, and then compressed by a roll press to a thickness of 200 μm. Finally, the negative electrode (negative electrode plate) of Examples 1-5 and a comparative example was produced by cutting to a desired size. The size of the area where the active material layer of the negative electrode was applied was 142 mm long and 237 mm wide, and the negative electrode (negative electrode current collector) was 142 mm long and 251 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) in which ethylene carbonate (EC) and diethyl carbonate (DEC) were mixed at a volume ratio of 30:70.

<Examples 1-5>
[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, 24 positive plates and 25 negative plates were used so that the negative plates were located outside the positive plates. Further, by using 48 separators, the separator was positioned on the outermost side of the electrode group (laminated body). In addition, in the state which has a negative electrode plate in the outermost layer, the whole is separately wrapped with a separator, and insulation with an exterior container is aimed at.

  As the separator, a microporous polyethylene film having a thickness of 25 μm was used. The size of the separator was 145 mm in length and 240 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.

Next, the second plate-like member is welded to the first plate-like member by laser pulse welding and welded so as to surround the convex portion (concave portion). A water electrolyte was injected. As described above, the replenishing non-aqueous electrolyte solution was prepared by dissolving 1 mol / L of LiPF ₆ in a mixed solution (solvent) obtained by mixing ethylene carbonate (EC) and diethyl carbonate (DEC) at a volume ratio of 30:70. What was done was used. In addition, 10 ml of replenishment non-aqueous electrolyte was poured into each space portion (space portion on the opposite side of the protruding portion in the convex portion). When a plurality of convex portions were formed on the sealing plate, 10 ml of replenishment non-aqueous electrolyte was poured into each of the plurality of convex portions. Thereafter, 0.5 g of a resin material as a sealing member (three-bond Lithium-ion battery sealant Three Bond 1171) as a sealing member was applied to the hole into which the nonaqueous electrolyte for replenishment was poured, and then dried, This hole was sealed.

  And the electrode group (laminated body) was accommodated in this exterior can, the sealing board was mounted, and the sealing board was fillet welded by laser pulse welding. Thereafter, about 200 ml of non-aqueous electrolyte was injected under reduced pressure from a φ2 mm injection hole provided in advance on the sealing plate. After the injection, a metal ball having the same diameter as the injection hole was placed in the injection hole, and the injection hole was sealed by resistance welding. In this way, five batteries of Examples 1 to 5 were produced.

<Comparative example>
[Assembly of secondary battery]
In this comparative example, a lithium ion secondary battery was assembled in the same manner as described above except that the nonaqueous electrolyte for replenishment was not injected. In addition, the five lithium ion secondary batteries by a comparative example were produced similarly to Examples 1-5.

  Thus, the nominal voltage of the lithium ion secondary battery by Examples 1-5 and a comparative example which were produced was 3.2V, and internal resistance was 3 m (ohm). The discharge capacity was 50 Ah when charged at an ambient temperature of 25 ° C. and a constant current / constant voltage of 10 A / 3.8 V for 6 hours and discharged at 10 A to 2.25 V.

  In addition, the lithium ion secondary batteries according to Examples 1 to 5 are such that the nonaqueous electrolyte for replenishment is stored in the space, and a new nonaqueous electrolyte is supplied to the electrode group. This is different from the comparative example in which no nonaqueous electrolyte for replenishment is stored and no new nonaqueous electrolyte is supplied to the electrode group.

  Then, using the lithium ion secondary batteries according to Examples 1 to 5 and the comparative example, a cycle test was performed under the above charge and discharge conditions at an ambient temperature of 40 ° C., and a discharge at the 1500th cycle with respect to a discharge capacity at the 1st cycle The capacity ratio (discharge capacity retention) was compared. The results are shown in Table 2. In addition, the discharge capacity retention in Table 2 indicates the average value of each of the five batteries subjected to the cycle test.

  As shown in Table 2 above, in Examples 1 to 5, it was confirmed that the discharge capacity retention rate was improved as compared with the comparative example. Specifically, in Examples 1 to 5, the capacity retention after 1500 cycles was 85% or more, and a high discharge capacity retention was obtained. Further, in Examples 1 and 4, although the discharge capacity retention rate was slightly lowered as compared with Examples 2, 3 and 5, a high discharge capacity retention rate of 87% and 88% was still obtained. As described above, the reason why the high capacity retention ratio was obtained in Examples 1 to 5 was that the nonaqueous electrolyte for replenishment leaked to the electrode group side, so that a new nonaqueous electrolyte was supplied to the electrode group. This is probably because On the other hand, in the comparative example, the discharge capacity retention after 1500 cycles was 70% or less (69%), which was lower than in Examples 1-5. This is considered to be because, in the comparative example, unlike Examples 1 to 5, a new non-aqueous electrolyte is not supplied to the electrode group. In Examples 1 and 4, the discharge capacity retention rate was low. In Examples 1 and 4, only one convex portion (space portion) was formed, and a plurality of convex portions (space portions) were formed. This is probably because the amount of the non-aqueous electrolyte stored in the space portion was small (because the amount of the non-aqueous electrolyte supplied was small) as compared to Examples 2, 3 and 5.

  In this way, the nonaqueous electrolyte for replenishment is stored in the space provided by the formation of the convex portion, and the nonaqueous electrolyte for replenishment is electroded through the sealing member (hole). It was confirmed that by making it leak to the group side, the charge / discharge cycle characteristics can be improved, and the battery life characteristics can be improved. Moreover, since the rigidity of a sealing board can be improved by forming a convex part in a sealing board, the improvement of the pressure resistance of an exterior container and the improvement of battery characteristics (life extension) are obtained simultaneously.

  In addition, although the charge / discharge cycle test is performed by an acceleration test, the deterioration rate of the sealing member (sealing resin) is also accelerated, and thus the leakage rate of the non-aqueous electrolyte is considered to be increased. . For this reason, it is considered that the same result can be obtained even in a normal use state.

  Further, from the results shown in Table 1 and Table 2, the shape of the convex portion of the sealing plate (first plate-like member) is the same as that in the fourth, sixth, and eighth to twelfth embodiments. Even in this case, it can be easily predicted that the effect of improving the rigidity of the sealing plate and the effect of improving the life characteristics can be obtained.

(13th Embodiment)
FIG. 62 is a schematic diagram of a photovoltaic power generation system according to a thirteenth embodiment of the present invention. Next, with reference to FIG. 62, a solar power generation system according to a thirteenth embodiment of the present invention will be described.

  As shown in FIG. 62, the solar power generation system according to the thirteenth embodiment includes a solar cell 1500 and a power storage battery (secondary battery) 1600 for storing the power generated by the solar cell 1500. Yes. In the thirteenth embodiment, a secondary battery similar to the lithium ion secondary battery shown in the first to twelfth embodiments is used as the storage battery 1600 for power storage.

  The storage battery 1600 is composed of one or a plurality of lithium ion secondary batteries. Note that the number n of connections of the storage battery 1600 (n is a natural number including 0) can be set to an arbitrary number according to the power generation capacity of the solar battery 1500. When a plurality of storage batteries 1600 are connected, the connection method may be serial connection or parallel connection. Moreover, the structure which mixed serial connection and parallel connection may be sufficient. Arbitrary means can be used as connection means of the storage battery 1600.

  In the thirteenth embodiment, the storage battery 1600 is installed so that the sealing plate is positioned on the upper side (top side) so that the nonaqueous electrolyte for replenishment is supplied to the electrode group side.

  The solar cell 1500 is connected to the control system 1700, and the storage battery 1600 is connected to the solar cell 1500 via the control system 1700. In addition, an inverter 1710 is connected to the output side of the storage battery 1600. Then, the electric power generated in the solar cell 1500 is charged in the storage battery 1600, and the electric power is supplied to the DC utilization device 1720 and the AC utilization device 1730 by the storage battery 1600.

  For example, the electric power generated in the solar cell 1500 may be supplied to the AC utilization device 1730 and the system linkage 1740 via the inverter 1710 without passing through the storage battery 1600 after detecting the amount of power generation by the control system 1700.

  In the solar power generation system according to the thirteenth embodiment, as described above, by providing the storage battery 1600 for power storage, the power generated by the solar battery 1500 is charged to the storage battery 1600 during the day, and the storage battery 1600 is discharged at night. The electric power stored in the storage battery 1600 can be used. In addition, the use of the lithium ion secondary battery shown in the first to twelfth embodiments as the storage battery 1600 for power storage makes it possible to realize a long life of the power storage facility. The cost can be reduced. In addition, by using a lithium ion secondary battery for the storage battery 1600, the storage battery 1600 has a storage device of the same scale as compared to the case of using a battery other than a lithium ion secondary battery such as a lead storage battery or a nickel hydride secondary battery. The entire system can be reduced in size and weight.

In addition, when using a lithium ion secondary battery for a domestic | home-use solar power generation system, it is necessary to make safety high especially. Therefore, as the active material used for the positive electrode, various compounds represented by the general formula Li _x MPO ₄ (M is one or more transition metals) having an olivine structure and high thermal stability during charging are used. preferable. In particular, lithium iron phosphate is preferable because it is less decomposed and has high safety.

(14th Embodiment)
FIG. 63 is a schematic diagram of a wind power generation system according to a fourteenth embodiment of the present invention. Next, with reference to FIG. 63, the wind power generation system by 14th Embodiment of this invention is demonstrated.

  As shown in FIG. 63, the wind power generation system according to the fourteenth embodiment includes a windmill 2000 having a power generation function, and a storage battery (secondary battery) 2100 for storing power that stores the power generated by the windmill 2000. ing. In the fourteenth embodiment, a secondary battery similar to the lithium ion secondary battery shown in the first to twelfth embodiments is used as the storage battery 2100 for power storage. In addition, the installation number n (n is a natural number including 0) of the windmill 2000 can be set to an arbitrary number.

  Further, the storage battery 2100 for storing electric energy is composed of one or a plurality of lithium ion secondary batteries, and the number thereof can be set to an arbitrary number according to the power generation capability of the windmill 2000. When a plurality of storage batteries 2100 are connected, the connection method may be serial connection or parallel connection. Moreover, the structure which mixed serial connection and parallel connection may be sufficient. Any means can be used as means for connecting the storage battery 2100.

  The windmill 2000 is connected to the control device 2300 via a transformer (transformer) 2200. The control device 2300 is connected to the storage battery 2100, the inverter 2400, and the system linkage protection device 2500. The storage battery 2100 connected to the control device 2300 is also connected to the system linkage protection device 2500 and the inverter 2400. Further, the system linkage protection device 2500 is also connected to the inverter 2400. A resistor 2600 is connected between the windmill 2000 and the transformer 2200.

  In the wind power generation system configured as described above, after the electric power generated by the windmill 2000 is transformed by the transformer 2200, the control device 2300 supplies the power to the storage battery 2100, the inverter 2400, and the system linkage protection device 2500. Sorted. When power is supplied to the storage battery 2100, the storage battery 2100 is charged with the supplied power. On the other hand, when power is supplied to the grid link protection apparatus 2500, power is sent from the grid link protection apparatus 2500 to the power grid 2700. In addition, when power is supplied to the inverter 2400, power is supplied to the power utilization device 2800 via the inverter 2400. Further, for example, when the power supply from the windmill 2000 is stopped, the power is supplied to the system linkage protection device 2500 and the inverter 2400 by the storage battery 2100. And the supplied electric power is supplied to the electric power grid | system 2700 and the electric power utilization apparatus 2800 via the grid cooperation protection apparatus 2500 and the inverter 2400, respectively.

  In the wind power generation system according to the fourteenth embodiment, as described above, the use of the lithium ion secondary battery shown in the first to twelfth embodiments as the storage battery 2100 for power storage extends the life of the power storage equipment. Therefore, the cost of the entire wind power generation system can be reduced. In addition, by using a lithium ion secondary battery for the storage battery 2100, the storage battery 2100 is equipped with power storage equipment of the same scale as compared to the case of using a battery other than a lithium ion secondary battery such as a lead storage battery or a nickel hydride secondary battery. The entire system can be reduced in size and weight.

(Fifteenth embodiment)
FIG. 64 is a schematic view of an electric bicycle according to a fifteenth embodiment of the present invention. Next, an electric bicycle (vehicle) according to a fifteenth embodiment of the present invention will be described with reference to FIG.

  The electric bicycle according to the fifteenth embodiment is a bicycle with a drive assisting device that assists the driving force with an electric motor, and is equipped with a storage battery 3000 for supplying electric power to the electric motor as shown in FIG. As the storage battery 3000, a secondary battery similar to the lithium ion secondary battery shown in the first to twelfth embodiments is used.

  In the electric bicycle according to the fifteenth embodiment, as described above, the storage battery 3000 for supplying electric power to the electric motor uses a lithium ion secondary battery having a higher energy density than a nickel-hydrogen secondary battery or the like. Thus, the storage battery 3000 can be reduced in size and weight. Thereby, since weight reduction of the whole bicycle can be achieved, the operability of the bicycle can be improved. In addition, the design freedom in the bicycle can be improved by downsizing the storage battery 3000.

(Sixteenth embodiment)
FIG. 65 is a schematic diagram of an electric railway vehicle according to a sixteenth embodiment of the present invention. Next, with reference to FIG. 65, an electric railway vehicle according to a sixteenth embodiment of the present invention will be described.

  As shown in FIG. 65, the electric railway vehicle according to the sixteenth embodiment is equipped with a storage battery 4000 for supplying electric power to an electric motor as a power source. For the storage battery 4000, a secondary battery similar to the lithium ion secondary battery shown in the first to twelfth embodiments is used. And when there is no power supply from a power transmission overhead line, electric power is supplied to an electric motor by discharge of the storage battery 4000. FIG.

  The electric power from the storage battery 4000 is used not only for driving the electric motor but also for operating an electric device such as an air conditioner or a lighting device in the vehicle.

  Thus, in the electric railway vehicle according to the sixteenth embodiment, by mounting the storage battery 4000 for supplying electric power to the electric motor, it is possible to travel even in a place where no electric power is supplied from the power transmission overhead line. For this reason, since it is difficult to install a power transmission overhead line geographically and economically, it becomes possible to drive an electric railway vehicle even in a section where an internal combustion powered vehicle such as diesel is used. For this reason, it is possible to reduce carbon dioxide emissions by running an electric railway vehicle instead of the internal combustion powered vehicle. Therefore, by configuring as described above, it is possible to provide a transportation means with a small environmental load.

  In the current railway operation system, since the power is collectively controlled, in the event of a power failure or the like, the railway vehicle stops and passengers are left behind in the vehicle. At this time, when power cannot be obtained due to the operation of the air conditioner, the temperature inside the vehicle increases and passenger stress increases. However, by mounting the storage battery 4000 on the vehicle, even when the power supply is stopped, the electric device can be operated as usual using the power of the storage battery 4000.

  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.

  For example, in the first to twelfth embodiments, 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 to this, and a wound lithium ion secondary battery is used. The present invention may be applied.

  Moreover, in the said 1st-12th embodiment, although the example which applied this invention to the lithium ion secondary battery (nonaqueous electrolyte secondary battery) which is an example of a secondary battery was shown, this invention is not limited to this. First, the present invention may be applied to nonaqueous electrolyte secondary batteries other than lithium ion 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.

  Further, in the first to twelfth embodiments, the example in which the convex portion having the space for storing the nonaqueous electrolyte for replenishment is formed on the sealing plate, but the present invention is not limited thereto, You may form the convex part which has the space part which stores the nonaqueous electrolyte for replenishment in the bottom face of an exterior can. In this case, in order to increase the rigidity of the sealing plate, it is preferable to form ribs or protrusions on the sealing plate. Moreover, you may form the convex part which has the space part which stores the nonaqueous electrolyte for replenishment in both the sealing board and the bottom face of an exterior can. However, it is preferable to form a convex portion having a space for storing a nonaqueous electrolyte for replenishment on the sealing plate, since the effect of improving the rigidity of the sealing plate and the effect of improving the life characteristics can be obtained at the same time.

  In the first to twelfth embodiments, the shape, size, depth, and the like of the convex portion can be changed as appropriate. Moreover, the structure of the convex part of the said 1st-12th embodiment can also be combined suitably. Furthermore, various changes can be made to the size and shape of the outer container (sealing plate, outer can).

  In the first to twelfth embodiments, the second plate member is welded to the first plate member of the sealing plate, so that the opening of the concave portion of the first plate member is closed with the second plate member. Although the example comprised in this way was shown, if it is comprised so that the opening part of the recessed part of a 1st plate-shaped member can be plugged up, the structure of those other than the above may be sufficient. For example, instead of the second plate-like member, a sheet-like member may be bonded with an adhesive or the like so that the opening portion of the first plate-like member is closed with this sheet-like member.

  Moreover, in the said 1st-12th embodiment, although the example which sealed the hole of the convex part with the sealing member (sealing resin) which consists of resin materials was shown, this invention is not restricted to this, For example, You may make it seal a hole with a screw | thread. That is, the leaking part may be constituted by a screw. Specifically, as shown in FIGS. 66 and 67, for example, an M2 screw hole 5100 is formed in the convex portion of the first plate-like member 70, and this screw hole 5100 is sealed with a screw 5200. . The M2 screw means a screw conforming to the ISO metric screw. In this case, if the pitch of the screws 5200 is configured so that the non-aqueous electrolyte LQ gradually flows (leaks) from between the screws 5200 and the screw holes 5100 (gap between the male screw and the female screw). Good. A specific screw pitch can be selected in accordance with the product life design, for example, a pitch of 0.4 or the like. In addition, it is preferable that the O-ring 5300 (see FIG. 66) or the sealing material 5400 (see FIG. 67) is inserted into the screw 5200 that seals the screw hole 5100 so as to maintain airtightness. The O-ring 5300 is preferably made of a material that can withstand an organic electrolyte, for example, SBR, EPDM, butyl rubber, silicon rubber, fluororesin-containing rubber, and the like. The sealing material 5400 is made of a material resistant to an organic electrolyte, such as polypropylene (PP), polyethylene (PE), a copolymer of PP and PE, SBR, EPDM, butyl rubber, silicon rubber, fluororesin-containing rubber, PTFE ( It is preferably composed of Teflon sealing tape (polytetrafluoroethylene) or the like (Teflon: registered trademark). Moreover, you may comprise from the resin similar to resin which can be used for an O-ring, a sealing material, and a sealing member also in the screw | thread which comprises a leak part. Furthermore, it is preferable that the screw 5200 is tightened with such a torque that the nonaqueous electrolyte LQ for replenishment is supplied (leaks) to the electrode group side due to an increase in the internal pressure of the outer container. Moreover, when the screw 5200 is used as the sealing member, for example, the sealing plate can be assembled as follows. After sealing the screw hole 5100 of the convex portion with the screw 5200, the second plate-like member provided with the liquid injection hole in advance is welded to the first plate-like member. Next, the nonaqueous electrolyte LQ for replenishment is injected from the injection hole of the second plate-shaped member. Thereafter, the liquid injection hole of the second plate member is sealed. Thereby, the sealing board provided with the nonaqueous electrolyte LQ for replenishment is comprised.

  Moreover, in the said 1st-12th embodiment, the example which formed one hole for supplying the nonaqueous electrolyte for replenishment to the electrode group side in the convex part (concave part, space part) of a sealing board is formed. Although shown, this invention is not restricted to this, You may form several said hole part in the convex part (concave part, space part) of a sealing board.

  Moreover, in the said 1st-12th embodiment, although the example which formed the said hole in the side surface of the recessed part provided by formation of a convex part was shown, this invention is not restricted to this, The said hole is formed in the bottom face of a recessed part. May be formed. Moreover, you may form a hole in both a side surface and a bottom face.

  In the first to twelfth embodiments, a liquid injection hole for injecting a nonaqueous electrolyte for replenishment may be formed in the second plate member of the sealing plate.

  Moreover, in the said 1st-12th embodiment, you may make the bottom face (bottom surface of a recessed part) into an inclined surface so that the nonaqueous electrolyte for replenishment may flow toward a hole (leakage part).

  Moreover, although the said 1st-12th embodiment showed the example which formed the injection hole for inject | pouring a nonaqueous electrolyte in the side wall part of the short side direction in an exterior can. However, the liquid injection hole may be formed at a position other than the above as long as the nonaqueous electrolyte can be injected into the space in which the electrode group is accommodated. For example, as shown in FIG. 68, the liquid injection hole 65 may be formed in the side wall 62 on one side in the long side direction (X direction) of the outer can 60. In addition, although the example which provided the safety valve 66 in the vicinity of the liquid injection hole 65 was shown in FIG. 68, the position of the safety valve 66 may be a position other than the position shown in FIG.

  Further, in the above embodiment, since the gap is formed between the sealing plate and the electrode group by forming the convex portion on the sealing plate, the nonaqueous electrolytic solution is poured from the liquid injection hole after the sealing plate is welded. When the liquid is poured, the non-aqueous electrolyte can be flowed to the side different from the liquid injection hole through the gap. For example, taking the configuration of the first embodiment as an example, the gap portion 100 a is formed between the sealing plate 90 and the electrode group 50 due to the formation of the convex portion 71 as shown in FIG. 26. Therefore, for example, in the case where the injection hole 65 is formed at the position shown in FIG. 68, when the non-aqueous electrolyte is injected, by tilting the lithium ion secondary battery as shown in FIG. The non-aqueous electrolyte injected from the injection hole 65 flows to the opposite side of the injection hole 65 through the gap 100a. Therefore, the injected nonaqueous electrolytic solution can be infiltrated into the electrode group 50 from the side opposite to the side where the injection hole 65 is formed. Thereby, the penetration of the non-aqueous electrolyte can be improved. In other embodiments other than the first embodiment, the penetration of the non-aqueous electrolyte can be improved as described above.

  In the first to twelfth embodiments, the active material layer is formed on both sides of the current collector. However, the present invention is not limited to this, and the active material layer is formed only on one side of the current collector. May be. 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.

  In the first to twelfth embodiments, the positive electrode and the negative electrode are disposed so that the positive electrode collector exposed portion and the negative electrode collector exposed portion are located on opposite sides. The invention is not limited to this, and the positive electrode and the negative electrode may be 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 same side.

  Moreover, in the said 1st-12th embodiment, although the example which formed the electrical power collector exposure part in the end of an electrical power collector was shown, this invention is not restricted to this, The said electrical power collector exposure part is, for example, You may form in the both ends of a collector. Further, a configuration other than such a configuration may be used.

  Moreover, although the said 1st-12th embodiment showed the example which formed two electrode terminals (a positive electrode terminal, a negative electrode terminal) in the side wall part of the long side in an armored can, this invention is not limited to this. The electrode terminal may be formed at a position other than the above. For example, the electrode terminal 64 may be formed at the position shown in FIG. 70, or the electrode terminal 64 may be formed at the position shown in FIG.

  Moreover, in the said embodiment, when the convex part (space part) is formed in multiple numbers in the sealing board, the nonaqueous electrolyte solution for replenishment stored in each space part has different supply speed (leakage speed). It can also be configured to be supplied (leaked) to the electrode group side. For example, when a screw is used as a sealing member for sealing the hole of the convex portion (space portion), the supply rate (leakage rate) of the non-aqueous electrolyte from each space portion is changed by changing the screw pitch or the like. Can do. Specifically, the supply start time (leakage start time) of the non-aqueous electrolyte is obtained by using a screw with a large pitch or by combining a female screw at the tolerance position G and a male screw at the tolerance position e (> f> g). ) Can be shortened. In addition, the tolerance position said here represents the dimensional tolerance with respect to a reference | standard dimension, as demonstrated by JISB0209-1. In addition, when a resin material is used for the sealing member that seals the hole of the convex part (space part), the supply rate (leakage rate) of the non-aqueous electrolyte from each space part can be changed by changing the amount of resin material used. ) Can be changed. For example, the supply start time (leakage start time) of the non-aqueous electrolyte can be shortened by reducing the amount of sealing resin covering the hole. In this way, it is possible to easily design the product life by changing the supply rate (leakage rate) of the non-aqueous electrolyte from each space.

  In the first, second, and ninth to twelfth embodiments, a hole (replenishment non-aqueous electrolyte is added to the side surface on the one end side of the recess (the side surface on the one end side in the long side direction). Although the example which formed the hole part for supplying to the electrode group side was shown, this invention is not restricted to this, A hole part is provided in the side surface (side surface of the both ends part of a long side direction) at the both ends part side of a recessed part, respectively May be formed. If comprised in this way, since the nonaqueous electrolyte for replenishment can be supplied to the both ends of an electrode group, the permeation of a nonaqueous electrolyte can be made favorable. In addition, you may form the said hole in side surfaces other than the above (for example, side surface of a short side direction).

  Moreover, the lithium ion secondary battery shown in the first to twelfth embodiments is for a hybrid vehicle (HEV) or an electric vehicle (EV), in addition to a solar power generation system, a wind power generation system, an electric bicycle, and an electric railway vehicle. It can also be used as a storage battery.

DESCRIPTION OF SYMBOLS 10 Positive electrode 11 Positive electrode collector 11a Current collector exposed part 12 Positive electrode active material layer 20 Negative electrode 21 Negative electrode current collector 21a Current collector exposed part 22 Negative electrode active material layer 30 Separator 50 Electrode group 50a Laminate 60 Outer can (storage container) )
64 Electrode terminal 65 Injection hole 66 Safety valve 67 Folded part 70 First plate member 70a Short side 70b Long side 71, 271, 371, 471, 571,
671, 771, 871, 971, 1071, 1271 Convex part 71a, 271a, 371a Corner part 72, 272, 372, 572, 772,
1072, 1272 Recess 73, 273, 373, 473, 573,
673, 773, 873, 1273 Space portion 74 Hole portion 75 Sealing member 80 Second plate member 90 Sealing plate (sealing body)
DESCRIPTION OF SYMBOLS 100 Exterior container 1500 Solar cell 1600, 2100, 3000, 4000 Storage battery 1700 Control system 1710, 2400 Inverter 1720 DC utilization apparatus 1730 Alternation apparatus 2000 Windmill 2200 Transformer 2300 Control apparatus 2500 System cooperation protection apparatus 2600 Resistor 2700 Electric power system 2800 Electricity utilization machine

Claims (23)

An electrode group including a positive electrode and a negative electrode arranged to face the positive electrode;
An outer container enclosing the electrode group together with an electrolyte solution;
Provided in the exterior container, and protruding to the electrode group side, and provided with a convex portion having a space portion in which a replenishing electrolyte is disposed on the surface side opposite to the electrode group side,
The exterior container includes a storage container that stores the electrode group, and a sealing body that seals the storage container,
The convex portion includes a leaking portion for leaking the replenishing electrolyte solution disposed in the space portion to the electrode group side, and is the largest surface among the surfaces constituting the sealing body and the storage container. A secondary battery, characterized by being provided on at least one of the above.   The sealing body includes a first plate-like member on which the convex portion is formed, and a second plate-like member attached to the first plate-like member so as to cover the space portion of the convex portion. The secondary battery according to claim 1, wherein the secondary battery is characterized. The leakage portion is
A hole provided in the convex portion;
The secondary battery according to claim 1, further comprising: a sealing member that seals the hole and leaks the electrolytic solution in the space to the electrode group side.   The secondary battery according to claim 3, wherein the sealing member is made of a resin material that swells with an electrolytic solution and leaks the electrolytic solution in the space to the electrode group side after a predetermined time has elapsed. .   The secondary battery according to claim 4, wherein the resin material includes at least one selected from styrene butadiene rubber, ethylene propylene diene monomer, butyl rubber, silicon rubber, and fluororesin-containing rubber.   The secondary battery according to claim 1, wherein the convex portion is configured to have a groove shape when viewed from a side opposite to the electrode group. . The surface on which the convex portion in the outer container is provided is formed in a substantially rectangular shape when seen in a plan view,
The secondary battery according to claim 1, wherein the convex portion is formed to extend in a long side direction. The surface on which the convex portion in the outer container is provided is formed in a substantially rectangular shape when seen in a plan view,
The secondary battery according to claim 1, wherein the convex portion is formed to extend in a direction intersecting the long side direction. The surface on which the convex portion in the outer container is provided is formed in a substantially rectangular shape including a long side and a short side when seen in a plan view.
The secondary battery according to claim 1, wherein the convex portion has a substantially rhombus shape.   10. The secondary battery according to claim 9, wherein the convex portions constituting the substantially rhombic shape are arranged such that each diagonal line is parallel to a long side and a short side of the exterior container.   The secondary battery according to claim 1, wherein the convex part includes one or more leakage parts. A plurality of the convex portions are formed,
The secondary battery according to claim 1, wherein the leakage portion is formed in each of the plurality of convex portions. The surface on which the convex portion in the outer container is provided is formed in a substantially rectangular shape when seen in a plan view,
The secondary battery according to claim 12, wherein at least some of the plurality of convex portions are formed to extend in a long side direction. The surface on which the convex portion in the outer container is provided is formed in a substantially rectangular shape when seen in a plan view,
14. The secondary battery according to claim 12, wherein at least a part of the plurality of convex portions is formed to extend in a direction intersecting the long side direction.   15. The secondary battery according to claim 12, wherein at least a part of the plurality of convex portions is configured in a substantially rhombus shape when seen in a plan view.   The secondary battery according to claim 1, wherein the leakage portion is formed at a position that does not contact the electrode group.   The secondary battery according to any one of claims 1 to 16, wherein a corner portion of the convex portion is rounded or chamfered.   The secondary battery according to claim 1, wherein a width of the space portion formed by the convex portion is 5 mm or more. A separator disposed between the positive electrode and the negative electrode;
The secondary battery according to any one of claims 1 to 18, wherein the electrode group is configured in a stacked structure by sequentially stacking the positive electrode, the separator, and the negative electrode. The surface of the storage container having the largest area is the bottom surface,
The secondary battery according to any one of claims 1 to 19, wherein the positive electrode and the negative electrode are accommodated in the storage container so as to face the bottom surface portion.   A photovoltaic power generation system comprising the secondary battery according to any one of claims 1 to 20.   A wind power generation system comprising the secondary battery according to any one of claims 1 to 20.   A vehicle comprising the secondary battery according to any one of claims 1 to 20.

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