WO2013094207A1 - Sealed battery - Google Patents

Sealed battery Download PDF

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Publication number
WO2013094207A1
WO2013094207A1 PCT/JP2012/008157 JP2012008157W WO2013094207A1 WO 2013094207 A1 WO2013094207 A1 WO 2013094207A1 JP 2012008157 W JP2012008157 W JP 2012008157W WO 2013094207 A1 WO2013094207 A1 WO 2013094207A1
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WO
WIPO (PCT)
Prior art keywords
battery
battery case
thickness
side wall
sealing
Prior art date
Application number
PCT/JP2012/008157
Other languages
French (fr)
Japanese (ja)
Inventor
恭介 宮田
廣樹 井上
Original Assignee
パナソニック株式会社
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Filing date
Publication date
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Publication of WO2013094207A1 publication Critical patent/WO2013094207A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings, jackets or wrappings of a single cell or a single battery
    • H01M50/147—Lids or covers
    • H01M50/166—Lids or covers characterised by the methods of assembling casings with lids
    • H01M50/169—Lids or covers characterised by the methods of assembling casings with lids by welding, brazing or soldering
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings, jackets or wrappings of a single cell or a single battery
    • H01M50/102—Primary casings, jackets or wrappings of a single cell or a single battery characterised by their shape or physical structure
    • H01M50/107—Primary casings, jackets or wrappings of a single cell or a single battery characterised by their shape or physical structure having curved cross-section, e.g. round or elliptic
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings, jackets or wrappings of a single cell or a single battery
    • H01M50/147—Lids or covers
    • H01M50/166—Lids or covers characterised by the methods of assembling casings with lids
    • H01M50/171—Lids or covers characterised by the methods of assembling casings with lids using adhesives or sealing agents
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a sealed battery, and more particularly to an improvement of a battery case used for a sealed battery.
  • a sealed battery such as a nonaqueous electrolyte secondary battery represented by a secondary battery is known.
  • a method is adopted in which a groove is provided in the vicinity of the opening of the battery case, and a sealing plate is disposed above the groove to perform caulking and sealing.
  • the sealing plate is provided with a PTC (positive temperature coefficient) thermistor whose resistance increases due to temperature rise and cuts off the current, or the internal pressure of the battery is predetermined.
  • PTC positive temperature coefficient
  • many safety parts such as a current-cutting valve body that mechanically breaks the electrical connection part and a gas discharge valve body that opens to lower the internal pressure are contained in the battery. Contained.
  • the caulking portion may be loosened before the safety parts are activated, and the sealing plate may come off and jump out.
  • Patent Document 1 describes a technique for increasing the sealing strength by increasing the thickness of the sealing portion of the battery case.
  • the temperature and pressure in the battery at the time of abnormality may increase more rapidly. Therefore, even if the sealing plate can be prevented from popping out by increasing the thickness of the sealing part of the battery case to increase the sealing strength, the pressure inside the battery When the rise is further applied, there is a possibility that a crack is generated on the side wall of the battery case.
  • a battery pack has been developed as a power source for driving an electric vehicle or the like by gathering a large number of batteries to increase the capacity and output.
  • a crack occurs in the side wall of the battery case before the valve element is operated and high temperature gas is released from the sealing plate,
  • the surrounding battery may be exposed to other batteries in a chain due to exposure of the high temperature gas to the surrounding batteries.
  • the present invention has been made in view of the above problems, and its main purpose is to operate the valve body from the sealing plate even when the temperature and pressure in the battery suddenly rise in the event of an abnormality. It is an object of the present invention to provide a sealed battery in which cracks are prevented from occurring on the side wall of the battery case before the high temperature gas is released.
  • the present invention provides a sealed battery in which a power generation element is housed in a battery case together with an electrolyte.
  • the battery case is caulked and sealed by a sealing plate at a sealing portion of the battery case.
  • T1 and T2 satisfy the following relational expressions (1) and (2). .
  • the present invention when the battery is abnormal, before the high temperature gas is released from the sealing plate by operating the valve body, it is possible to suppress the occurrence of cracks on the side wall of the battery case, and to provide a highly safe sealing. Type battery can be obtained.
  • the present inventors have increased the capacity of a sealed lithium ion battery (hereinafter simply referred to as “battery”) in which the thickness of the sealing portion of the battery case is the same as the thickness of the side wall or thicker than the thickness of the side wall.
  • battery for example, a volume energy density of 600 Wh / L or more
  • a forced heating test was performed on a battery (for example, a volume energy density of 600 Wh / L or more)
  • the volume energy density of 600 Wh / L or more is 2900 mAh or more for the 18650 size, 2100 mAh or more for the 16650 size, and 4900 mAh or more for the 22650 size.
  • the present inventors if the sealing plate is scattered before the side wall of the battery case is cracked, the side wall of the battery case before the valve element is activated and the high temperature gas is released from the sealing plate. It was thought that the crack which generate
  • the battery pack is usually configured by arranging a plurality of batteries in parallel with the sealing plate facing upward, even if high temperature gas is released from the sealing plate of the battery in which an abnormality has occurred, the peripheral battery is In addition, the hot gas is not directly exposed.
  • an exhaust duct that discharges the high-temperature gas released from the sealing plate to the outside is provided in parallel with the battery arrangement direction, the other batteries may be discharged from the sealing plate of the battery in which an abnormality has occurred. Will not be exposed to.
  • the present invention relates to a sealed battery in which a power generation element is housed in a battery case together with an electrolyte.
  • the battery case is caulked and sealed by a sealing plate at a sealing portion of the battery case, and the thickness of the sealing portion of the battery case is set to T1.
  • Tm thickness of the side wall of the battery case is T2 (mm)
  • T1 and T2 satisfy the following relational expressions (1) and (2).
  • the above relational expression (1) shows the condition that the crack is not generated in the side wall of the battery case before the valve body is actuated and the high temperature gas is released from the sealing plate
  • the relational expression (2) The conditions which satisfy
  • the above relational expression (1) indicates that the sealing plate scatters before the side wall of the battery case is cracked, and that the side wall of the battery case does not crack and the sealing plate does not scatter. Includes both phenomena. That is, the present invention suppresses the occurrence of cracks in the side walls of the battery case by scattering the sealing plate even in the worst case, assuming that no cracks are generated in the side walls of the battery case.
  • the thickness of the sealing portion of the battery case it is preferable not to change the thickness of the sealing portion of the battery case but to change the thickness of the side wall of the battery case.
  • the external dimensions of the battery are defined by the standard
  • the sealing plate is composed of a plurality of safety components, it is necessary to individually change the design of each safety component so as to satisfy reliability and safety according to the size of the sealing plate to be changed. Therefore, a great amount of time and man-hours are required for battery design by changing the thickness of the sealing portion.
  • the thickness of the side wall of the battery case even when the outer dimensions are made constant, it can be handled only by changing the diameter of the electrode group, so that the battery design can be easily changed.
  • the sealing portion of the battery case refers to a portion from the lower end of the groove portion of the battery case to the opening end portion.
  • the side wall of the battery case refers to a portion of the side surface other than the sealing portion on the side surface of the battery case.
  • the side wall of the battery case does not need to have a uniform thickness in the height direction of the battery case, and may satisfy the above relational expression (1).
  • the central portion may be thicker than other portions.
  • the thickness of the bottom surface of the battery case is preferably 0.3 mm or more from the viewpoint of moldability. Furthermore, it is preferable that a groove that is broken by an increase in pressure inside the battery is formed on the bottom surface of the battery case. By forming this groove, it is possible to further prevent cracking of the side wall of the battery case.
  • the thickness of the groove formed on the bottom is preferably in the range of 0.02 mm to 0.18 mm from the viewpoint of the strength and safety of the battery case.
  • the material of the battery case in the present invention is preferably, for example, a material obtained by applying nickel plating to iron as a base material from the viewpoint of strength, electrolyte resistance, and workability.
  • FIG. 1 is a cross-sectional view showing a configuration of a cylindrical lithium ion battery 20 according to an embodiment of the present invention.
  • FIG. 2 is a cross-sectional view showing a configuration of a conventional cylindrical lithium ion battery 21.
  • an electrode group 4 in which a positive electrode 1 and a negative electrode 2 are wound through a separator 3 is housed in a battery case 5 together with a non-aqueous electrolyte. Insulating plates 6 and 9 are disposed above and below the electrode group 4, the positive electrode 1 is joined to the filter 12 through the positive electrode lead 8, and the negative electrode 2 is also used as the negative electrode terminal through the negative electrode lead 7. Is joined to the bottom.
  • the filter 12 is connected to an inner cap 13, and the protrusion of the inner cap 13 is joined to a metal valve body 14. Further, the valve body 14 is connected to a sealing plate 10 that also serves as a positive electrode terminal. And the sealing board 10, the valve body 14, the inner cap 13, and the filter 12 are united, and the sealing part (opening part) of the battery case 5 is caulked and sealed via the gasket 11.
  • valve body 14 When an internal short circuit or the like occurs in the battery 20 and the pressure in the battery 20 increases, the valve body 14 swells toward the sealing plate 10, and when the inner cap 13 and the valve body 14 are disconnected, the current path is interrupted. Is done. When the pressure in the battery 20 further increases, the inner cap 13 and the valve body 14 are broken. As a result, the gas generated in the battery 20 is discharged to the outside through the through hole 12 a of the filter 12, the tear of the inner cap 13 and the valve body 14, and the opening 10 a of the sealing plate 10.
  • the safety mechanism for discharging the gas generated in the battery 20 to the outside is not limited to the structure shown in FIG.
  • the battery case 5 is processed so as to satisfy the following relational expressions (1) and (2) when the thickness of the sealing portion 5b of the battery case 5 is T1 and the thickness of the side wall 5c is T2. Yes.
  • T2 ⁇ 0.88T1 + 0.05 (1) 0.15 ⁇ T1 ⁇ 0.30 (2)
  • T2> T1 the thickness of the side wall 5 c of the battery case 5 is thicker than the thickness of the sealing portion 5 b of the battery case 5.
  • the thickness of the sealing portion 51b of the battery case 51 is processed to be thicker than the thickness of the side wall 51c.
  • the electrode group 4 is housed together with the electrolyte, and the opening of the battery case 51 is sealed with a sealing plate 10 via a gasket.
  • the side wall 51c of the battery case is thin. Before the hot gas is released from the battery, cracks may occur in the side wall 51c of the battery case, and the hot gas may be ejected therefrom.
  • the battery case 5 is processed so that the thickness T1 of the sealing portion 5b and the thickness T2 of the side wall 5c satisfy the above relational expressions (1) and (2).
  • the thickness T1 of the sealing portion 5b and the thickness T2 of the side wall 5c satisfy the above relational expressions (1) and (2).
  • the battery of the present invention is applied to a battery pack in which a plurality of batteries are assembled, it is possible to suppress the release of high temperature gas from the battery case side wall of the battery in which an abnormality has occurred. Exposure can be prevented. As a result, it is possible to prevent an abnormal battery from chain-burning to other batteries, and to realize a highly safe battery pack.
  • the bottom surface 7 of the battery case 5 has a groove 15 that is broken by an increase in the pressure inside the battery.
  • the shape of the groove 15 is not particularly limited, but the thickness of the groove 15 formed on the bottom surface 7 may be in the range of 0.02 mm to 0.18 mm from the viewpoint of the strength and safety of the battery case 5. preferable.
  • cylindrical lithium ion battery of the present invention the following materials can be used.
  • the positive electrode plate 1 has a configuration in which a positive electrode active material layer is formed on a positive electrode current collector.
  • a positive electrode current collector aluminum, an aluminum alloy, stainless steel, titanium, a titanium alloy, or the like can be used.
  • a lithium-containing transition metal compound for example, a composite metal oxide of lithium and a metal such as cobalt, manganese, nickel, chromium, iron, vanadium, or the like can be used.
  • the positive electrode active material layer is prepared by preparing a slurry-like mixture in which a positive electrode active material, a binder, and a conductive agent are kneaded and dispersed together with a dispersion medium, and attaching this mixture to the positive electrode current collector. Can be formed.
  • the positive electrode active material is preferably a lithium composite nickel oxide containing nickel.
  • a lithium composite nickel oxide containing nickel has a larger capacity than LiCoO 2 , is inexpensive, and has a high energy density. Therefore, a battery having a high energy density can be obtained.
  • the lithium composite nickel oxide generates a larger amount of gas when the battery is abnormal than LiCoO 2 .
  • the valve element operates and hot gas is discharged from the sealing plate. It is possible to suppress the occurrence of cracks in the side wall of the battery case before being released. Therefore, a high capacity and high safety battery can be provided.
  • the negative electrode plate 2 has a configuration in which a negative electrode active material layer is formed on a negative electrode current collector.
  • a negative electrode current collector copper, copper alloy, nickel, nickel alloy, stainless steel, aluminum, aluminum alloy, or the like can be used.
  • carbon materials such as natural graphite and artificial graphite, metal oxide materials such as tin oxide and silicon oxide, silicon-containing compounds such as silicon and silicide, and the like can be used.
  • the negative electrode active material layer can be formed by adhering a negative electrode active material, a binder, a dispersion medium, and, if necessary, a slurry-like mixture containing a conductive material to the negative electrode current collector.
  • the separator 3 can be made of a polyolefin-based material such as polyethylene, polypropylene, or ethylene-propylene copolymer.
  • the electrolyte is prepared by dissolving a lithium salt in a non-aqueous solvent.
  • a non-aqueous solvent ethylene carbonate, propylene carbonate, dimethyl carbonate, or the like can be used.
  • the lithium salt LiPF 6 , LiBF 4 , LiClO 4, or the like can be used.
  • a positive electrode mixture paste was prepared by mixing 100 parts by mass of a positive electrode active material, 1.7 parts by mass of polyvinylidene fluoride as a binder, and 2.5 parts by mass of acetylene black as a conductive agent in a liquid component.
  • the positive electrode mixture paste was applied to both surfaces of a positive electrode current collector made of an aluminum foil except for the connecting portions of the positive electrode leads 8, dried, and then rolled to obtain the positive electrode plate 1. At this time, the positive electrode plate 1 was rolled so as to have a thickness of 163 ⁇ m.
  • the aluminum foil used as the positive electrode current collector had a length of 573 mm, a width of 57 mm, and a thickness of 15 ⁇ m.
  • the positive electrode plate 1 was cut to a predetermined size, and an aluminum positive electrode lead 8 was connected to the exposed portion of the positive electrode current collector by ultrasonic welding.
  • the copper foil used as the negative electrode current collector had a length of 658 mm, a width of 58.5 mm, and a thickness of 10 ⁇ m.
  • the negative electrode plate 2 was cut into a predetermined size, and a negative electrode lead 7 made of nickel was connected to the exposed portion of the negative electrode current collector by resistance welding.
  • LiPF 6 lithium hexafluorophosphate
  • the battery case 5 was produced by drawing.
  • the battery case 5 is obtained by changing the thickness T1 of the sealing portion 5b to a range of 0.12 mm to 0.30 mm and the thickness T2 of the side wall 5c to a range of 0.08 mm to 0.36 mm. , Respectively.
  • the thickness of the bottom surface of the battery case 5 was 0.3 mm
  • a C-shaped groove was provided on the bottom surface
  • the thickness of the groove was 0.05 mm.
  • Battery assembly The positive electrode plate 1 and the negative electrode plate 2 were spirally wound through a separator 3 made of a microporous polyethylene resin having a thickness of 25 ⁇ m to produce an electrode group 4.
  • the electrode group 4 was inserted into the battery case 5 via a polypropylene lower insulating plate 9, and the negative electrode lead 7 connected to the negative electrode plate 2 and the bottom surface of the battery case 5 were connected by resistance welding. .
  • the U side having a width of 1.0 mm and a depth of 1.5 mm is formed on the opening side of the battery case 5 above the upper insulating plate 6.
  • a letter-shaped groove was formed in the circumferential direction by plastic working.
  • the battery 20 was manufactured by caulking and sealing the opening 5.
  • This battery 20 had a diameter of 18 mm, a height of 65 mm, and a design capacity of 3200 mAh (volume energy density of 700 Wh / L).
  • Table 1 is a table showing the number of batteries in which the sealing plate was scattered and the number of batteries with cracks on the side walls of the battery case when a heating test was performed on each battery produced.
  • the thickness T1 of the sealing part of the battery case is 0.12 mm
  • scattering of the sealing plate and cracks on the side wall occurred in all the batteries having the battery case side wall thickness T2 of 0.08 to 0.19 mm.
  • the thickness T1 of the sealing part of the battery case is 0.15 mm
  • the battery with side wall thicknesses T2 of 0.10 and 0.12 mm causes scattering of the sealing plate and cracking of the battery case side wall.
  • the batteries with side wall thickness T2 of 0.19 and 0.22 mm were cracked on the side wall of the battery case, although some batteries had the sealing plate scattered. There was no battery. This is presumably because the sealing plate was scattered before the pressure inside the battery increased and the side wall of the battery case cracked, thereby preventing the side wall of the battery case from cracking.
  • FIG. 4 is a graph showing the test results shown in Table 2.
  • the horizontal axis indicates the thickness T1 of the sealing portion of the battery case
  • the vertical axis indicates the thickness T2 of the side wall of the battery case.
  • circles indicate that the side wall of the battery case is not cracked
  • square marks indicate that the side wall of the battery case is cracked.
  • relational expression (1) indicates a condition in which a crack is not generated on the side wall of the battery case before the valve element is operated and the high temperature gas is released from the sealing plate.
  • relational expression (2) shows the conditions which satisfy
  • the above relational expression (1) indicates that the sealing plate scatters before the side wall of the battery case is cracked, and that the side wall of the battery case does not crack and the sealing plate does not scatter. Includes both phenomena. That is, the present invention suppresses the occurrence of cracks in the side walls of the battery case by scattering the sealing plate even in the worst case, assuming that no cracks are generated in the side walls of the battery case.
  • LiNi 0.8 Co 0.15 Al 0.05 O 2 was used as the positive electrode active material.
  • the present invention is not limited to this, and the general formula Li x Ni y M 1-y O 2 (x: 0.95 ⁇ x ⁇ 1.15, 0.6 ⁇ y ⁇ 1, and M is a lithium nickel composite oxide represented by Co, Mn, Cr, Fe, W, Mg, Zr, Ti, and Al) Can do.
  • the lithium ion secondary battery whose volume energy density is 700 Wh / L was demonstrated, it is not limited to this, It is suitable for a lithium ion secondary battery whose volume energy density is 600 Wh / L or more. Applicable to.
  • the lithium ion secondary battery has been described as an example. However, the present invention is not limited to this, and can be applied to other nonaqueous electrolyte secondary batteries, alkaline storage batteries, and the like.
  • the sealed battery of the present invention is suitable for use as a main power source for consumer mobile tools such as mobile phones and laptop computers, a main power source for power tools such as an electric screwdriver, and an industrial main power source such as an EV car.

Abstract

A sealed secondary battery wherein an electric power generating element is contained in a battery case together with an electrolyte. A battery case (5) is caulked at a sealing part (5b) of the battery case (5) with use of a sealing plate (10). If T1 (mm) is the thickness of the sealing part (5b) of the battery case (5) and T2 (mm) is the thickness of a side wall (5c) of the battery case (5), T1 and T2 satisfy the following relational expressions (1) and (2). T2 ≥ 0.85T1 + 0.06 (1) 0.15 ≤ T1 ≤ 0.30 (2)

Description

密閉型電池Sealed battery
　本発明は密閉型電池に関し、特に密閉型電池に用いられる電池ケースの改良に関する。 The present invention relates to a sealed battery, and more particularly to an improvement of a battery case used for a sealed battery.
　近年、ＡＶ機器あるいはパソコンなどの電子機器のポータブル化、コードレス化が急速に進んでおり、これらの駆動用電源として、高容量のアルカリ蓄電池に代表される水系電解液二次電池や、リチウムイオン二次電池に代表される非水電解液二次電池などの密閉型電池が知られている。 In recent years, electronic devices such as AV devices and personal computers are rapidly becoming portable and cordless. As a power source for driving these devices, an aqueous electrolyte secondary battery represented by a high-capacity alkaline storage battery, a lithium ion secondary battery, or the like. A sealed battery such as a nonaqueous electrolyte secondary battery represented by a secondary battery is known.
　このような密閉型電池の一般的な封口方法としては、電池ケースの開口部の近傍に溝部を設け、その溝部の上部に封口板を配置して、かしめ封口する方法が採用されている。 As a general sealing method for such a sealed battery, a method is adopted in which a groove is provided in the vicinity of the opening of the battery case, and a sealing plate is disposed above the groove to perform caulking and sealing.
　ところで、密閉型電池は、充電器等の故障や誤使用により、過充電・過放電が起きた場合、化学反応により電池内部の温度が急激に上昇すると同時に、ガスが発生し、電池の内部圧力が増大して、電池が不安全な状態になるおそれがある。 By the way, when an overcharge / overdischarge occurs due to a failure or misuse of a charger or the like, a sealed battery generates a gas at the same time as the temperature inside the battery suddenly increases due to a chemical reaction. May increase and the battery may become unsafe.
　そのような状態になるのを避けるために、封口板に、温度の上昇により抵抗が上がり電流を遮断するＰＴＣ（positive temperature coefficient：正温度係数）サーミスタを設けたり、あるいは、電池の内部圧力が所定値以上になったとき、電気的結合部を機械的に破断する電流遮断用の弁体、さらには、開口して内部圧力を下げるガス排出用の弁体など、多くの安全部品が電池内に収容されている。 In order to avoid such a state, the sealing plate is provided with a PTC (positive temperature coefficient) thermistor whose resistance increases due to temperature rise and cuts off the current, or the internal pressure of the battery is predetermined. When the value exceeds the value, many safety parts such as a current-cutting valve body that mechanically breaks the electrical connection part and a gas discharge valve body that opens to lower the internal pressure are contained in the battery. Contained.
　しかしながら、密閉型電池の異常時において、かしめによる封口強度が弱い場合は、安全部品が作動する前に、かしめ部がゆるみ、封口板が外れて飛び出すおそれがある。 However, if the sealing strength due to caulking is weak when the sealed battery is abnormal, the caulking portion may be loosened before the safety parts are activated, and the sealing plate may come off and jump out.
　そこで、封口板の飛び出しを防止するために、特許文献１には、電池ケースの封口部の厚みを厚くすることによって、封口強度を上げる技術が記載されている。 Therefore, in order to prevent the sealing plate from popping out, Patent Document 1 describes a technique for increasing the sealing strength by increasing the thickness of the sealing portion of the battery case.
特開平４－２９６４４４号公報JP-A-4-296444
　しかしながら、近年のさらなる高エネルギー密度化に伴い、異常時における電池内の温度及び圧力は、より急激に上昇するおそれがある。そのため、電池ケースの封口部の厚みを厚くして封口強度をあげることによって、封口板の飛び出しを防ぐことができても、電池内の温度上昇によるケース強度の低下に加えて、電池内の圧力上昇がさらに加わることによって、電池ケースの側壁に亀裂が発生するおそれがある。 However, with the further increase in energy density in recent years, the temperature and pressure in the battery at the time of abnormality may increase more rapidly. Therefore, even if the sealing plate can be prevented from popping out by increasing the thickness of the sealing part of the battery case to increase the sealing strength, the pressure inside the battery When the rise is further applied, there is a possibility that a crack is generated on the side wall of the battery case.
　近年、電気自動車などの駆動用電源として、多数の電池を集合して、大容量、高出力化を図った電池パックが開発されている。このような電池パックを構成する複数の電池の一つに異常が発生した場合、弁体が作動して封口板から高温ガスが放出される前に、電池ケースの側壁に亀裂が発生して、そこから高温のガスが噴出すると、周辺の電池に高温ガスがさらされることによって、連鎖的に他の電池にまで類焼が及ぶおそれがある。 In recent years, a battery pack has been developed as a power source for driving an electric vehicle or the like by gathering a large number of batteries to increase the capacity and output. When an abnormality occurs in one of a plurality of batteries constituting such a battery pack, a crack occurs in the side wall of the battery case before the valve element is operated and high temperature gas is released from the sealing plate, When hot gas is ejected from there, the surrounding battery may be exposed to other batteries in a chain due to exposure of the high temperature gas to the surrounding batteries.
　本発明は、上記課題に鑑みてなされたもので、その主な目的は、異常時において、電池内の温度と圧力が急激に上昇した場合であっても、弁体が作動して封口板から高温ガスが放出される前に、電池ケースの側壁に亀裂が発生するのを抑制した密閉型電池を提供することを目的とする。 The present invention has been made in view of the above problems, and its main purpose is to operate the valve body from the sealing plate even when the temperature and pressure in the battery suddenly rise in the event of an abnormality. It is an object of the present invention to provide a sealed battery in which cracks are prevented from occurring on the side wall of the battery case before the high temperature gas is released.
　上記目的を達成するために、本発明は、発電要素が電解質とともに電池ケースに収容された密閉型電池において、電池ケースは、該電池ケースの封口部において、封口板によってかしめ封口されており、電池ケースの封口部の厚みをＴ１（ｍｍ）、電池ケースの側壁の厚みをＴ２（ｍｍ）としたとき、Ｔ１及びＴ２が、以下の関係式（１）及び（２）を満たすことを特徴とする。 To achieve the above object, the present invention provides a sealed battery in which a power generation element is housed in a battery case together with an electrolyte. The battery case is caulked and sealed by a sealing plate at a sealing portion of the battery case. When the thickness of the sealing portion of the case is T1 (mm) and the thickness of the side wall of the battery case is T2 (mm), T1 and T2 satisfy the following relational expressions (1) and (2). .
　　Ｔ２≧０．８８Ｔ１＋０．０５・・・・（１）
　　０．１５≦Ｔ１≦０．３０　　・・・・（２） T2 ≧ 0.88T1 + 0.05 (1)
0.15 ≦ T1 ≦ 0.30 (2)
　本発明によれば、電池の異常時において、弁体が作動して封口板から高温ガスが放出される前に、電池ケースの側壁に亀裂が発生するのを抑制し、安全性に優れた密閉型電池を得ることができる。 According to the present invention, when the battery is abnormal, before the high temperature gas is released from the sealing plate by operating the valve body, it is possible to suppress the occurrence of cracks on the side wall of the battery case, and to provide a highly safe sealing. Type battery can be obtained.
本発明の一実施形態における円筒形リチウムイオン電池の構成を示した断面図である。It is sectional drawing which showed the structure of the cylindrical lithium ion battery in one Embodiment of this invention. 従来の円筒形リチウムイオン電池の構成を示した断面図である。It is sectional drawing which showed the structure of the conventional cylindrical lithium ion battery. 本発明の一実施形態における円筒形リチウムイオン電池の底面図である。It is a bottom view of the cylindrical lithium ion battery in one embodiment of the present invention. 本発明における電池ケースの封口部の厚みと電池ケースの側壁の厚みとの関係を示したグラフである。It is the graph which showed the relationship between the thickness of the sealing part of the battery case in this invention, and the thickness of the side wall of a battery case.
　本発明者等は、電池ケースの封口部の厚みを、側壁の厚みと同じ、又は、側壁の厚みよりも厚くした密閉型リチウムイオン電池（以下、単に、「電池」という）において、容量を大きくした電池（例えば、体積エネルギー密度が６００Ｗｈ／Ｌ以上）に対して、強制的な加熱試験を行っていたところ、弁体が作動して封口板から高温ガスが放出される前に、電池ケースの側壁に亀裂が発生する現象が、ｐｐｍオーダで発生するのを見出した。 The present inventors have increased the capacity of a sealed lithium ion battery (hereinafter simply referred to as “battery”) in which the thickness of the sealing portion of the battery case is the same as the thickness of the side wall or thicker than the thickness of the side wall. When a forced heating test was performed on a battery (for example, a volume energy density of 600 Wh / L or more), before the valve body was activated and high temperature gas was released from the sealing plate, It has been found that the phenomenon of cracking on the side wall occurs on the order of ppm.
　体積エネルギー密度が６００Ｗｈ／Ｌ以上とは、電池のサイズと設計容量でおきなおすと、１８６５０サイズのとき２９００ｍＡｈ以上、１６６５０サイズのとき２１００ｍＡｈ以上、２２６５０サイズのとき４９００ｍＡｈ以上である。 The volume energy density of 600 Wh / L or more is 2900 mAh or more for the 18650 size, 2100 mAh or more for the 16650 size, and 4900 mAh or more for the 22650 size.
　そこで、本発明者等は、電池ケースの側壁に亀裂が発生する前に、封口板を飛散させれば、弁体が作動して封口板から高温ガスが放出される前に、電池ケースの側壁に発生する亀裂を抑制し、電池ケースの側面から高温ガスが放出されるのを抑制できると考えた。これにより、多数の電池を集合した電池パックにおいて、異常の発生した電池の電池ケース側壁から高温ガスが放出されて、周辺の電池に高温ガスがさらされるのを抑制することができる。その結果、異常の発生した電池から、連鎖的に他の電池に類焼が及ぶのを防止でき、安全性の高い電池パックが実現できる。 Therefore, the present inventors, if the sealing plate is scattered before the side wall of the battery case is cracked, the side wall of the battery case before the valve element is activated and the high temperature gas is released from the sealing plate. It was thought that the crack which generate | occur | produces in a battery can be suppressed and it can suppress that a hot gas is discharge | released from the side of a battery case. Thereby, in a battery pack in which a large number of batteries are assembled, it is possible to suppress the high temperature gas from being released from the battery case side wall of the battery in which an abnormality has occurred, and the high temperature gas being exposed to the surrounding batteries. As a result, it is possible to prevent an abnormal battery from chain-burning to other batteries, and to realize a highly safe battery pack.
　なお、電池パックは、通常、複数の電池が封口板を上向けにして並列に配列して構成されているため、異常の発生した電池の封口板から高温ガスが放出されても、周辺の電池に、直接、高温ガスがさらされることはない。また、電池の配列方向に平行に、封口板から放出された高温ガスを外部に排出する排気ダクトを設けておけば、他の電池が、異常の発生した電池の封口板から放出された高温ガスにさらされることはない。 In addition, since the battery pack is usually configured by arranging a plurality of batteries in parallel with the sealing plate facing upward, even if high temperature gas is released from the sealing plate of the battery in which an abnormality has occurred, the peripheral battery is In addition, the hot gas is not directly exposed. In addition, if an exhaust duct that discharges the high-temperature gas released from the sealing plate to the outside is provided in parallel with the battery arrangement direction, the other batteries may be discharged from the sealing plate of the battery in which an abnormality has occurred. Will not be exposed to.
　本発明は、発電要素が電解質とともに電池ケースに収容された密閉型電池において、電池ケースは、該電池ケースの封口部において、封口板によってかしめ封口されており、電池ケースの封口部の厚みをＴ１（ｍｍ）、電池ケースの側壁の厚みをＴ２（ｍｍ）としたとき、Ｔ１及びＴ２が、以下の関係式（１）及び（２）を満たすことを特徴とする。 The present invention relates to a sealed battery in which a power generation element is housed in a battery case together with an electrolyte. The battery case is caulked and sealed by a sealing plate at a sealing portion of the battery case, and the thickness of the sealing portion of the battery case is set to T1. (Mm), where the thickness of the side wall of the battery case is T2 (mm), T1 and T2 satisfy the following relational expressions (1) and (2).
　　Ｔ２≧０．８８Ｔ１＋０．０５・・・・（１）
　　０．１５≦Ｔ１≦０．３０　　・・・・（２）
　本発明によれば、電池の異常時において、電池内の温度と圧力が急激に上昇した場合であっても、弁体が作動して封口板から高温ガスが放出される前に、電池ケースの側壁に亀裂が発生するのを抑制した密閉型電池を提供することができる。 T2 ≧ 0.88T1 + 0.05 (1)
0.15 ≦ T1 ≦ 0.30 (2)
According to the present invention, even when the temperature and pressure in the battery suddenly rises when the battery is abnormal, the battery body operates before the high temperature gas is released from the sealing plate by operating the valve body. It is possible to provide a sealed battery in which cracks are suppressed from occurring on the side wall.
　上記の関係式（１）は、弁体が作動して封口板から高温ガスが放出される前に、電池ケースの側壁に亀裂が発生しない条件を示し、関係式（２）は、電池ケースの封口部をかしめる際の封口強度、及び加工性を満たす条件を示すものである。すなわち、封口板の厚みＴ１が０．１５ｍｍより薄いと、封口強度が不足し、弁体が作動する前に、かしめ部がゆるみ、封口板が外れて飛び出すおそれがある。また、封口部の厚みＴ１が０．３０ｍｍより厚いと、かしめ封口に大きな力が必要となり、設備の大型化が必要となることから、経済的に不利となる。 The above relational expression (1) shows the condition that the crack is not generated in the side wall of the battery case before the valve body is actuated and the high temperature gas is released from the sealing plate, and the relational expression (2) The conditions which satisfy | fill the sealing intensity | strength at the time of caulking a sealing part, and workability are shown. That is, when the thickness T1 of the sealing plate is less than 0.15 mm, the sealing strength is insufficient, and the caulking portion may be loosened before the valve body is activated, and the sealing plate may come off and jump out. On the other hand, when the thickness T1 of the sealing part is larger than 0.30 mm, a large force is required for the caulking sealing, and the equipment is required to be enlarged, which is economically disadvantageous.
　なお、上記の関係式（１）は、電池ケースの側壁に亀裂が発生する前に、封口板が飛散する現象、及び、電池ケースの側壁に亀裂が発生せず、かつ、封口板が飛散しない現象の両方を含む。すなわち、本発明は、電池ケースの側壁に亀裂を発生させないことを前提に、最悪の場合でも、封口板を飛散させることにより、電池ケースの側壁に亀裂が発生するのを抑制するものである。 The above relational expression (1) indicates that the sealing plate scatters before the side wall of the battery case is cracked, and that the side wall of the battery case does not crack and the sealing plate does not scatter. Includes both phenomena. That is, the present invention suppresses the occurrence of cracks in the side walls of the battery case by scattering the sealing plate even in the worst case, assuming that no cracks are generated in the side walls of the battery case.
　本発明を実施するにあたり、電池ケースの封口部の厚みは変更せず、電池ケースの側壁を厚くするように変更することが好ましい。一般的に、電池の外形寸法は規格で規定されているため、電池ケースの封口部の厚みを変更する場合には、封口板の大きさを変更する必要が生じる。しかしながら、封口板は、複数の安全部品からなるため、それぞれの安全部品の設計を、変更する封口板の大きさに応じて、信頼性及び安全性を満たすよう個々に変更する必要が生じる。したがって、封口部の厚みの変更により、電池設計に多大な時間と工数が必要となる。一方、電池ケースの側壁の厚みを変更する場合は、外形寸法を一定にした場合でも、電極群の直径を変更するのみで対応できるため、容易に電池設計の変更が可能である。 In carrying out the present invention, it is preferable not to change the thickness of the sealing portion of the battery case but to change the thickness of the side wall of the battery case. Generally, since the external dimensions of the battery are defined by the standard, when changing the thickness of the sealing portion of the battery case, it is necessary to change the size of the sealing plate. However, since the sealing plate is composed of a plurality of safety components, it is necessary to individually change the design of each safety component so as to satisfy reliability and safety according to the size of the sealing plate to be changed. Therefore, a great amount of time and man-hours are required for battery design by changing the thickness of the sealing portion. On the other hand, when the thickness of the side wall of the battery case is changed, even when the outer dimensions are made constant, it can be handled only by changing the diameter of the electrode group, so that the battery design can be easily changed.
　ここで、電池ケースの封口部は、電池ケースの溝部の下端から開口端部までの部分をいう。また、電池ケースの側壁は、電池ケースの側面において、封口部以外の側面の部分をいう。なお、電池ケースの側壁は、電池ケースの高さ方向において、均等な厚みである必要はなく、上記の関係式（１）を満たしていればよい。例えば、亀裂の発生しやすい中央部の強度を強くするために、他の部分より中央部を厚くしてもよい。 Here, the sealing portion of the battery case refers to a portion from the lower end of the groove portion of the battery case to the opening end portion. Further, the side wall of the battery case refers to a portion of the side surface other than the sealing portion on the side surface of the battery case. In addition, the side wall of the battery case does not need to have a uniform thickness in the height direction of the battery case, and may satisfy the above relational expression (1). For example, in order to increase the strength of the central portion where cracks are likely to occur, the central portion may be thicker than other portions.
　また、電池ケースの底面の厚みは、成型加工性の観点から、０．３ｍｍ以上とすることが好ましい。さらに、この電池ケースの底面には、電池内部の圧力の増加によって破断する溝が形成されていることが好ましい。この溝を形成することで、さらに、電池ケースの側壁の亀裂を防ぐことが可能となる。なお、底面に形成される溝の厚みは、電池ケースの強度、および安全性の観点から０．０２ｍｍ～０．１８ｍｍの範囲にすることが好ましい。 Further, the thickness of the bottom surface of the battery case is preferably 0.3 mm or more from the viewpoint of moldability. Furthermore, it is preferable that a groove that is broken by an increase in pressure inside the battery is formed on the bottom surface of the battery case. By forming this groove, it is possible to further prevent cracking of the side wall of the battery case. The thickness of the groove formed on the bottom is preferably in the range of 0.02 mm to 0.18 mm from the viewpoint of the strength and safety of the battery case.
　なお、本発明における電池ケースの材料は、例えば、基材である鉄に、ニッケルメッキを施したものが、強度、耐電解質性、及び加工性の観点から好ましい。 The material of the battery case in the present invention is preferably, for example, a material obtained by applying nickel plating to iron as a base material from the viewpoint of strength, electrolyte resistance, and workability.
　以下、本発明の一実施形態について、図面を参照しながら説明する。 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
　図１は、本発明の一実施形態における円筒形リチウムイオン電池２０の構成を示した断面図である。また、図２は、従来例の円筒形リチウムイオン電池２１の構成を示した断面図である。 FIG. 1 is a cross-sectional view showing a configuration of a cylindrical lithium ion battery 20 according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing a configuration of a conventional cylindrical lithium ion battery 21.
　図１に示すように、正極１と負極２とがセパレータ３を介して捲回された電極群４が、非水電解液とともに、電池ケース５に収容されている。電極群４の上下には、絶縁板６、９が配され、正極１は、正極リード８を介してフィルタ１２に接合され、負極２は、負極リード７を介して負極端子を兼ねる電池ケース５の底部に接合されている。 As shown in FIG. 1, an electrode group 4 in which a positive electrode 1 and a negative electrode 2 are wound through a separator 3 is housed in a battery case 5 together with a non-aqueous electrolyte. Insulating plates 6 and 9 are disposed above and below the electrode group 4, the positive electrode 1 is joined to the filter 12 through the positive electrode lead 8, and the negative electrode 2 is also used as the negative electrode terminal through the negative electrode lead 7. Is joined to the bottom.
　フィルタ１２は、インナーキャップ１３に接続され、インナーキャップ１３の突起部は、金属製の弁体１４に接合されている。さらに、弁体１４は、正極端子を兼ねる封口板１０に接続されている。そして、封口板１０、弁体１４、インナーキャップ１３、及びフィルタ１２が一体となって、ガスケット１１を介して、電池ケース５の封口部（開口部）をかしめ封口している。 The filter 12 is connected to an inner cap 13, and the protrusion of the inner cap 13 is joined to a metal valve body 14. Further, the valve body 14 is connected to a sealing plate 10 that also serves as a positive electrode terminal. And the sealing board 10, the valve body 14, the inner cap 13, and the filter 12 are united, and the sealing part (opening part) of the battery case 5 is caulked and sealed via the gasket 11. FIG.
　電池２０に内部短絡等が発生して、電池２０内の圧力が上昇すると、弁体１４が封口板１０に向かって膨れ、インナーキャップ１３と弁体１４との接合がはずれると、電流経路が遮断される。さらに電池２０内の圧力が上昇すると、インナーキャップ１３及び弁体１４が破断する。これによって、電池２０内に発生したガスは、フィルタ１２の貫通孔１２ａ、インナーキャップ１３及び弁体１４の裂け目、そして、封口板１０の開放部１０ａを介して、外部へ排出される。 When an internal short circuit or the like occurs in the battery 20 and the pressure in the battery 20 increases, the valve body 14 swells toward the sealing plate 10, and when the inner cap 13 and the valve body 14 are disconnected, the current path is interrupted. Is done. When the pressure in the battery 20 further increases, the inner cap 13 and the valve body 14 are broken. As a result, the gas generated in the battery 20 is discharged to the outside through the through hole 12 a of the filter 12, the tear of the inner cap 13 and the valve body 14, and the opening 10 a of the sealing plate 10.
　なお、電池２０内に発生したガスを外部に排出する安全機構は、図１に示した構造に限定されず、他の構造のものであってもよい。 It should be noted that the safety mechanism for discharging the gas generated in the battery 20 to the outside is not limited to the structure shown in FIG.
　本発明において、電池ケース５は、電池ケース５の封口部５ｂの厚みをＴ１とし、側壁５ｃの厚みをＴ２としたとき、以下の関係式（１）、（２）を満たすように加工されている。 In the present invention, the battery case 5 is processed so as to satisfy the following relational expressions (1) and (2) when the thickness of the sealing portion 5b of the battery case 5 is T1 and the thickness of the side wall 5c is T2. Yes.
　　Ｔ２≧０．８８Ｔ１＋０．０５・・・・（１）
　　０．１５≦Ｔ１≦０．３０　　・・・・（２）
　ここで、上記の関係式（１）、（２）を満たすとき、Ｔ２＞Ｔ１の関係も満たす。すなわち、電池ケース５の側壁５ｃの厚みは、電池ケース５の封口部５ｂの厚みよりも厚い。 T2 ≧ 0.88T1 + 0.05 (1)
0.15 ≦ T1 ≦ 0.30 (2)
Here, when the above relational expressions (1) and (2) are satisfied, the relationship of T2> T1 is also satisfied. That is, the thickness of the side wall 5 c of the battery case 5 is thicker than the thickness of the sealing portion 5 b of the battery case 5.
　一方、図２に示すように、従来の電池２１では、電池ケース５１の封口部５１ｂの厚みは、側壁５１ｃの厚みよりも厚く加工されている。このような電池ケース５１に、電極群４が電解質とともに収納され、電池ケース５１の開口部は、ガスケットを介して封口板１０で封口されている。 On the other hand, as shown in FIG. 2, in the conventional battery 21, the thickness of the sealing portion 51b of the battery case 51 is processed to be thicker than the thickness of the side wall 51c. In such a battery case 51, the electrode group 4 is housed together with the electrolyte, and the opening of the battery case 51 is sealed with a sealing plate 10 via a gasket.
　従来の電池ケース５１を用いた電池２１では、電池の異常時において、電池内の温度と圧力が急激に増加した際、電池ケースの側壁５１ｃが薄いために、弁体が作動して封口板１０から高温ガスが放出される前に、電池ケースの側壁５１ｃに亀裂が発生して、そこから高温ガスが噴出するおそれがある。 In the battery 21 using the conventional battery case 51, when the temperature and pressure in the battery rapidly increase when the battery is abnormal, the side wall 51c of the battery case is thin. Before the hot gas is released from the battery, cracks may occur in the side wall 51c of the battery case, and the hot gas may be ejected therefrom.
　これに対して、本発明の電池では、電池ケース５を、封口部５ｂの厚みＴ１と、側壁５ｃの厚みＴ２とが、上記の関係式（１）、（２）を満たすように加工することによって、電池内の温度と圧力が急激に上昇した場合であっても、弁体１４が作動して封口板１０から高温ガスが放出される前に、電池ケースの側壁５ｃに亀裂が発生するのを抑制することができる。 On the other hand, in the battery of the present invention, the battery case 5 is processed so that the thickness T1 of the sealing portion 5b and the thickness T2 of the side wall 5c satisfy the above relational expressions (1) and (2). Thus, even when the temperature and pressure in the battery suddenly rise, a crack occurs in the side wall 5c of the battery case before the valve element 14 is activated and the high temperature gas is released from the sealing plate 10. Can be suppressed.
　従って、本発明の電池を、複数の電池を集合した電池パックに適用しても、異常の発生した電池の電池ケース側壁から高温ガスが放出するのを抑制できるため、周辺の電池に高温ガスがさらされるのを防止することができる。その結果、異常の発生した電池から、連鎖的に他の電池に類焼が及ぶのを防止でき、安全性の高い電池パックが実現することができる。 Therefore, even when the battery of the present invention is applied to a battery pack in which a plurality of batteries are assembled, it is possible to suppress the release of high temperature gas from the battery case side wall of the battery in which an abnormality has occurred. Exposure can be prevented. As a result, it is possible to prevent an abnormal battery from chain-burning to other batteries, and to realize a highly safe battery pack.
　また、電池ケース５の底面７には、図３に示すように、電池内部の圧力の増加によって破断する溝１５が形成されていることが好ましい。この溝１５を形成することで、さらに、電池ケース５の側壁の亀裂を防ぐことが可能となる。なお、溝１５の形状は特に限定されないないが、底面７に形成される溝１５の厚みは、電池ケース５の強度、および安全性の観点から０．０２ｍｍ～０．１８ｍｍの範囲にすることが好ましい。 Further, as shown in FIG. 3, it is preferable that the bottom surface 7 of the battery case 5 has a groove 15 that is broken by an increase in the pressure inside the battery. By forming the groove 15, it is possible to further prevent the side wall of the battery case 5 from cracking. The shape of the groove 15 is not particularly limited, but the thickness of the groove 15 formed on the bottom surface 7 may be in the range of 0.02 mm to 0.18 mm from the viewpoint of the strength and safety of the battery case 5. preferable.
　本発明の円筒形リチウムイオン電池は、構成材料として以下のものを用いることができる。 For the cylindrical lithium ion battery of the present invention, the following materials can be used.
　正極板１は、正極集電体上に正極活物質層が形成された構成からなる。正極集電体は、アルミニウム、アルミニウム合金、ステンレス鋼、チタン、チタン合金等を用いることができる。また、正極活物質としては、リチウム含有遷移金属化合物、例えば、コバルト、マンガン、ニッケル、クロム、鉄、バナジウム等の金属とリチウムとの複合金属酸化物が使用できる。正極活物質層は、正極活物質、結着剤、および導電剤を、分散媒とともに混練して分散させたスラリー状の合剤を調製し、この合剤を正極集電体に付着させることにより形成できる。 The positive electrode plate 1 has a configuration in which a positive electrode active material layer is formed on a positive electrode current collector. As the positive electrode current collector, aluminum, an aluminum alloy, stainless steel, titanium, a titanium alloy, or the like can be used. As the positive electrode active material, a lithium-containing transition metal compound, for example, a composite metal oxide of lithium and a metal such as cobalt, manganese, nickel, chromium, iron, vanadium, or the like can be used. The positive electrode active material layer is prepared by preparing a slurry-like mixture in which a positive electrode active material, a binder, and a conductive agent are kneaded and dispersed together with a dispersion medium, and attaching this mixture to the positive electrode current collector. Can be formed.
　本発明において、正極活物質は、ニッケルを含むリチウム複合ニッケル酸化物を用いることが好ましい。このようなニッケルを含む材料は、ＬｉＣｏＯ２よりも容量が大きく、安価であり、かつエネルギー密度が高いため、高エネルギー密度の電池を得ることができる。しかしながら、リチウム複合ニッケル酸化物は、ＬｉＣｏＯ２よりも、電池の異常時におけるガスの発生量が多量となる。本発明では、リチウム複合ニッケル酸化物を正極活物質として用いた場合でも、電池の異常時に、電池内の温度と圧力が急激に上昇しても、弁体が作動して封口板から高温ガスが放出される前に、電池ケースの側壁に亀裂が発生するのを抑制することができる。よって、高容量かつ高安全な電池を提供することができる。 In the present invention, the positive electrode active material is preferably a lithium composite nickel oxide containing nickel. Such a material containing nickel has a larger capacity than LiCoO 2 , is inexpensive, and has a high energy density. Therefore, a battery having a high energy density can be obtained. However, the lithium composite nickel oxide generates a larger amount of gas when the battery is abnormal than LiCoO 2 . In the present invention, even when lithium composite nickel oxide is used as the positive electrode active material, even if the temperature and pressure inside the battery suddenly rises when the battery is abnormal, the valve element operates and hot gas is discharged from the sealing plate. It is possible to suppress the occurrence of cracks in the side wall of the battery case before being released. Therefore, a high capacity and high safety battery can be provided.
　負極板２は、負極集電体上に負極活物質層が形成された構成からなる。負極集電体は、銅、銅合金、ニッケル、ニッケル合金、ステンレス鋼、アルミニウム、アルミニウム合金等を用いることができる。負極活物質としては、天然黒鉛や人造黒鉛などの炭素材料や、酸化錫、酸化珪素等の金属酸化物材料や、ケイ素、シリサイドなどのケイ素含有化合物、等を用いることができる。負極活物質層は、負極活物質、結着剤、および分散媒、必要により導電材を含んだスラリー状の合剤を負極集電体に付着させることにより形成できる。 The negative electrode plate 2 has a configuration in which a negative electrode active material layer is formed on a negative electrode current collector. As the negative electrode current collector, copper, copper alloy, nickel, nickel alloy, stainless steel, aluminum, aluminum alloy, or the like can be used. As the negative electrode active material, carbon materials such as natural graphite and artificial graphite, metal oxide materials such as tin oxide and silicon oxide, silicon-containing compounds such as silicon and silicide, and the like can be used. The negative electrode active material layer can be formed by adhering a negative electrode active material, a binder, a dispersion medium, and, if necessary, a slurry-like mixture containing a conductive material to the negative electrode current collector.
　セパレータ３は、ポリエチレン、ポリプロピレン、エチレン－プロピレン共重合体などのポリオレフィン系材料を用いることができる。 The separator 3 can be made of a polyolefin-based material such as polyethylene, polypropylene, or ethylene-propylene copolymer.
　電解質は、非水溶媒にリチウム塩を溶解することにより調製される。非水溶媒は、エチレンカーボネート、プロピレンカーボネート、ジメチルカーボネートなどが用いることができる。また、リチウム塩としては、ＬｉＰＦ６、ＬｉＢＦ４、ＬｉＣｌＯ４などを用いることができる。 The electrolyte is prepared by dissolving a lithium salt in a non-aqueous solvent. As the non-aqueous solvent, ethylene carbonate, propylene carbonate, dimethyl carbonate, or the like can be used. As the lithium salt, LiPF 6 , LiBF 4 , LiClO 4, or the like can be used.
　（実施例）
　以下、本発明の実施例を挙げて本発明の構成及び効果をさらに説明するが、本発明はこれら実施例に限定されるものではない。 (Example)
Hereinafter, although the example and the example of the present invention are given and the composition and effect of the present invention are further explained, the present invention is not limited to these examples.
　（１）正極板の作製
　正極活物質としてＬｉＮｉ0.8Ｃｏ0.15Ａｌ0.05Ｏ2を使用した。正極活物質１００質量部、結着剤としてポリフッ化ビニリデンフルオライド１．７質量部、及び導電剤としてアセチレンブラック２．５質量部を、液状成分に混合させて、正極合剤ペーストを調製した。この正極合剤ペーストを、アルミニウム箔からなる正極集電体の両面に、正極リード８の接続部分を除いて塗布、乾燥し、その後、圧延することで、正極板１を得た。このとき、厚みが１６３μｍとなるように正極板１を圧延した。また、正極集電体として使用したアルミニウム箔の長さは５７３ｍｍ、幅は５７ｍｍ、厚さは１５μｍであった。この正極板１を所定の寸法に裁断し、正極集電体の露出部にアルミニウム製の正極リード８を超音波溶着により接続した。 (1) Production of positive electrode plate LiNi 0.8 Co 0.15 Al 0.05 O 2 was used as a positive electrode active material. A positive electrode mixture paste was prepared by mixing 100 parts by mass of a positive electrode active material, 1.7 parts by mass of polyvinylidene fluoride as a binder, and 2.5 parts by mass of acetylene black as a conductive agent in a liquid component. The positive electrode mixture paste was applied to both surfaces of a positive electrode current collector made of an aluminum foil except for the connecting portions of the positive electrode leads 8, dried, and then rolled to obtain the positive electrode plate 1. At this time, the positive electrode plate 1 was rolled so as to have a thickness of 163 μm. The aluminum foil used as the positive electrode current collector had a length of 573 mm, a width of 57 mm, and a thickness of 15 μm. The positive electrode plate 1 was cut to a predetermined size, and an aluminum positive electrode lead 8 was connected to the exposed portion of the positive electrode current collector by ultrasonic welding.
　（２）負極板の作製
　負極活物質として易黒鉛化炭素を使用した。負極活物質１００質量部と、結着剤としてポリフッ化ビニリデンフルオライド０．６質量部と、増粘剤としてカルボキシメチルセルロース１質量部と、適量の水とを、練合機にて攪拌し、負極ペーストを得た。この負極合剤ペーストを、銅箔からなる負極集電体の両面に、負極リード７の接続部分を除いて塗布、乾燥し、その後、圧延することで、負極板２を得た。このとき、厚みが１６４μｍとなるように負極板２を圧延した。また、負極集電体として使用した銅箔の長さは６５８ｍｍ、幅は５８．５ｍｍ、厚さは１０μｍであった。この負極板２を所定の寸法に裁断し、負極集電体の露出部にニッケル製の負極リード７を抵抗溶接により接続した。 (2) Production of negative electrode plate Graphitizable carbon was used as the negative electrode active material. 100 parts by weight of the negative electrode active material, 0.6 parts by weight of polyvinylidene fluoride as a binder, 1 part by weight of carboxymethyl cellulose as a thickener, and an appropriate amount of water are stirred in a kneader, and the negative electrode A paste was obtained. This negative electrode mixture paste was applied to both surfaces of a negative electrode current collector made of copper foil except for the connecting portion of the negative electrode lead 7, dried, and then rolled to obtain the negative electrode plate 2. At this time, the negative electrode plate 2 was rolled so as to have a thickness of 164 μm. The copper foil used as the negative electrode current collector had a length of 658 mm, a width of 58.5 mm, and a thickness of 10 μm. The negative electrode plate 2 was cut into a predetermined size, and a negative electrode lead 7 made of nickel was connected to the exposed portion of the negative electrode current collector by resistance welding.
　（３）非水電解質の調整
　エチレンカーボネート（ＥＣ）、ジエチルカーボネート（ＤＥＣ）、およびエチルメチルカーボネート（ＥＭＣ）の混合溶媒に、電解質としてヘキサフルオロリン酸リチウム（ＬｉＰＦ６）が１．０ｍｏｌ／Ｌになるように溶解し、非水電解質を調整した。 (3) Preparation of non-aqueous electrolyte In a mixed solvent of ethylene carbonate (EC), diethyl carbonate (DEC), and ethyl methyl carbonate (EMC), lithium hexafluorophosphate (LiPF 6 ) as an electrolyte is adjusted to 1.0 mol / L. It melt | dissolved so that it might become, and the nonaqueous electrolyte was adjusted.
　（４）電池ケースの作製
　基材としての鉄鋼板に、ニッケルメッキを施した。その後、絞り加工により、電池ケース５を作製した。ここで、電池ケース５は、封口部５ｂの厚みＴ１を、０．１２ｍｍ～０．３０ｍｍの範囲に、また、側壁５ｃの厚みＴ２を、０．０８ｍｍ～０．３６ｍｍの範囲に変えたものを、それぞれ作製した。ここで、電池ケース５の底面の厚みは、０．３ｍｍとし、底面にＣ字状の溝を設け、溝の厚みは、０．０５ｍｍとした。 (4) Production of battery case Nickel plating was applied to the steel sheet as the base material. Thereafter, a battery case 5 was produced by drawing. Here, the battery case 5 is obtained by changing the thickness T1 of the sealing portion 5b to a range of 0.12 mm to 0.30 mm and the thickness T2 of the side wall 5c to a range of 0.08 mm to 0.36 mm. , Respectively. Here, the thickness of the bottom surface of the battery case 5 was 0.3 mm, a C-shaped groove was provided on the bottom surface, and the thickness of the groove was 0.05 mm.
　（５）電池の組立
　正極板１と負極板２とを、厚さ２５μｍの微多孔性ポリエチレン樹脂からなるセパレータ３を介して渦巻状に巻回し、電極群４を作製した。この電極群４を、電池ケース５の中に、ポリプロピレン製の下部絶縁板９を介して挿入し、負極板２に接続された負極リード７と、電池ケース５の底面とを抵抗溶接により接続した。 (5) Battery assembly The positive electrode plate 1 and the negative electrode plate 2 were spirally wound through a separator 3 made of a microporous polyethylene resin having a thickness of 25 μm to produce an electrode group 4. The electrode group 4 was inserted into the battery case 5 via a polypropylene lower insulating plate 9, and the negative electrode lead 7 connected to the negative electrode plate 2 and the bottom surface of the battery case 5 were connected by resistance welding. .
　次に、電極群４の上部に、ポリプロピレン製の上部絶縁板６を挿入した後、上部絶縁板６より上方の電池ケース５の開口部側に、幅１．０ｍｍ、深さ１．５ｍｍのＵ字状の溝部を円周方向に塑性加工によって形成した。 Next, after inserting the upper insulating plate 6 made of polypropylene into the upper part of the electrode group 4, the U side having a width of 1.0 mm and a depth of 1.5 mm is formed on the opening side of the battery case 5 above the upper insulating plate 6. A letter-shaped groove was formed in the circumferential direction by plastic working.
　その後、非水電解質を電池ケース５内に所定量注入した。そして、正極板１に接続された正極リード８を、封口板１０と、レーザー溶接により接続し、正極リード８を折り畳みながら、封口板１０を電池ケース５の溝部５ａの上に配置し、電池ケース５の開口部をかしめて封口し、電池２０を作製した。この電池２０は、直径が１８ｍｍ、高さが６５ｍｍであり、設計容量は３２００ｍＡｈ（体積エネルギー密度が７００Ｗｈ／Ｌ）であった。 Thereafter, a predetermined amount of nonaqueous electrolyte was injected into the battery case 5. Then, the positive electrode lead 8 connected to the positive electrode plate 1 is connected to the sealing plate 10 by laser welding, and while the positive electrode lead 8 is folded, the sealing plate 10 is disposed on the groove portion 5a of the battery case 5, and the battery case The battery 20 was manufactured by caulking and sealing the opening 5. This battery 20 had a diameter of 18 mm, a height of 65 mm, and a design capacity of 3200 mAh (volume energy density of 700 Wh / L).
　（６）加熱試験
　上記方法で作製した電池を各１０個ずつ準備し、以下のような条件で加熱試験を実施した。まず、２５℃の環境の下で、１５００ｍＡの電流により電池電圧が４．５Ｖになるまで充電した。充電後、各電池を２００℃に設定したホットプレートの上に置き、加熱した。 (6) Heat test Ten batteries each prepared by the above method were prepared, and a heat test was performed under the following conditions. First, in an environment of 25 ° C., the battery was charged with a current of 1500 mA until the battery voltage became 4.5V. After charging, each battery was placed on a hot plate set at 200 ° C. and heated.
　表１は、作製した各電池に対して、加熱試験を行い、封口板が飛散した電池の個数、及び、電池ケースの側壁に亀裂が生じた電池の個数を、それぞれ示した表である。 Table 1 is a table showing the number of batteries in which the sealing plate was scattered and the number of batteries with cracks on the side walls of the battery case when a heating test was performed on each battery produced.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　例えば、電池ケースの封口部の厚みＴ１が０．１２ｍｍの場合、電池ケースの側壁の厚みＴ２が０．０８～０．１９ｍｍの全ての電池において、封口板の飛散、及び側壁の亀裂が生じた電池があった。この場合、弁体が作動して封口板から高温ガスが放出される前に、電池ケースの側壁に亀裂が生じた電池もあった。 For example, when the thickness T1 of the sealing part of the battery case is 0.12 mm, scattering of the sealing plate and cracks on the side wall occurred in all the batteries having the battery case side wall thickness T2 of 0.08 to 0.19 mm. There was a battery. In this case, there was a battery in which a crack occurred in the side wall of the battery case before the valve body was operated and high temperature gas was released from the sealing plate.
　一方、電池ケースの封口部の厚みＴ１が０．１５ｍｍの場合、電池ケースの側壁の厚みＴ２が０．１０、０．１２ｍｍの電池では、封口板の飛散、及び電池ケースの側壁の亀裂が生じた電池があったのに対し、電池ケースの側壁の厚みＴ２が０．１９、０．２２ｍｍの電池では、封口板の飛散が生じた電池はあったものの、電池ケースの側壁に亀裂を生じた電池なかった。これは、電池内の圧力が高まって、電池ケースの側壁に亀裂が生じる前に、封口板が飛散することによって、電池ケースの側壁に亀裂が生じるのを防げたためと考えられる。 On the other hand, when the thickness T1 of the sealing part of the battery case is 0.15 mm, the battery with side wall thicknesses T2 of 0.10 and 0.12 mm causes scattering of the sealing plate and cracking of the battery case side wall. In contrast, the batteries with side wall thickness T2 of 0.19 and 0.22 mm were cracked on the side wall of the battery case, although some batteries had the sealing plate scattered. There was no battery. This is presumably because the sealing plate was scattered before the pressure inside the battery increased and the side wall of the battery case cracked, thereby preventing the side wall of the battery case from cracking.
　また、表１に示すように、電池ケースの封口部の厚みＴ１が厚くなるに従い、封口板の飛散が生じた電池の個数は減っているが、電池ケースの側壁の厚みＴ２が同じでも、電池ケースの封口部の厚みＴ１が異なると、電池ケースの側壁の亀裂発生に差が見られた。例えば、電池ケースの封口部の厚みＴ１が０．１５ｍｍで、電池ケースの側壁の厚みＴ２が０．１９ｍｍの電池では、封口板が飛散した電池は多かったが、電池ケースの側壁に亀裂が生じた電池はなかった。一方、電池ケースの封口部の厚みＴ１が０．２２ｍｍで、電池ケースの側壁の厚みＴ２が０．１９ｍｍの電池では、封口板が飛散した電池はなく、電池ケースの側壁に亀裂が生じた電池があった。前者の場合は、電池ケースの側壁に亀裂が生じる前に、封口板が飛散することによって、電池ケースの側壁に亀裂が生じるのを防げたのに対して、後者の場合は、封口板が飛散する前に、電池ケースの側壁に亀裂が生じたものと考えられる。従って、電池ケースの側壁の亀裂発生を抑制するには、電池ケースの封口部の厚みＴ１に応じて、電池ケースの側壁の厚みＴ２を定める必要がある。 Further, as shown in Table 1, as the thickness T1 of the sealing portion of the battery case increases, the number of batteries in which the sealing plate scatters is reduced, but even if the thickness T2 of the side wall of the battery case is the same, the battery When the thickness T1 of the sealing part of the case was different, a difference was observed in the occurrence of cracks on the side wall of the battery case. For example, in a battery having a battery case sealing portion thickness T1 of 0.15 mm and a battery case side wall thickness T2 of 0.19 mm, there were many batteries with the sealing plate scattered, but the battery case side wall cracked. There was no battery. On the other hand, in a battery having a battery case sealing portion thickness T1 of 0.22 mm and a battery case side wall thickness T2 of 0.19 mm, there is no battery in which the sealing plate is scattered, and the battery case has a crack in the side wall. was there. In the former case, the sealing plate scatters before the side wall of the battery case cracks, thereby preventing the side wall of the battery case from cracking, whereas in the latter case, the sealing plate scatters. It is considered that a crack occurred on the side wall of the battery case before Therefore, in order to suppress the occurrence of cracks on the side wall of the battery case, it is necessary to determine the thickness T2 of the side wall of the battery case according to the thickness T1 of the sealing portion of the battery case.
　図４は、表２に示した試験結果を、グラフに示したものである。ここで、横軸は、電池ケースの封口部の厚みＴ１を示し、縦軸は、電池ケースの側壁の厚みＴ２を示す。図４のグラフにおいて、丸印は、電池ケースの側壁に亀裂が生じなかったものを示し、四角の印は、電池ケースの側壁に亀裂が生じたものを示す。 FIG. 4 is a graph showing the test results shown in Table 2. Here, the horizontal axis indicates the thickness T1 of the sealing portion of the battery case, and the vertical axis indicates the thickness T2 of the side wall of the battery case. In the graph of FIG. 4, circles indicate that the side wall of the battery case is not cracked, and square marks indicate that the side wall of the battery case is cracked.
　図４に示すように、電池ケースの封口部の厚みＴ１、及び、電池ケースの側壁の厚みＴ２を、図中の斜線で示した範囲内に設定することによって、電池の異常時に、電池内の温度と圧力が急激に上昇しても、電池ケースの側壁に亀裂が発生するのを抑制することができる。 As shown in FIG. 4, by setting the thickness T1 of the sealing portion of the battery case and the thickness T2 of the side wall of the battery case within the range indicated by the oblique lines in the drawing, Even if the temperature and pressure rise rapidly, it is possible to prevent cracks from occurring on the side walls of the battery case.
　ここで、図４のＡで示す直線は、Ｔ２＝０．８８Ｔ１＋０．０５で表されるため、図４の斜線で示した範囲は、以下の関係式を満たす範囲となる。 Here, since the straight line indicated by A in FIG. 4 is represented by T2 = 0.88T1 + 0.05, the hatched range in FIG. 4 satisfies the following relational expression.
　　Ｔ２≧０．８８Ｔ１＋０．０５・・・・（１）
　　０．１５≦Ｔ１≦０．３０　　・・・・（２）
　上記の関係式（１）は、弁体が作動して封口板から高温ガスが放出される前に、電池ケースの側壁に亀裂が発生しない条件を示す。また、関係式（２）は、電池ケースの封口部をかしめる際の封口強度、及び加工性を満たす条件を示すものである。すなわち、電池ケースの封口部の厚みＴ１が０．１５ｍｍより薄いと、封口強度が不足し、弁体が作動する前に、かしめ部がゆるみ、封口板が外れて飛び出すおそれがある。また、電池ケースの封口部の厚みＴ１が０．３０ｍｍより厚いと、かしめ封口に大きな力が必要となり、設備の大型化が必要となることから、経済的に不利となる。 T2 ≧ 0.88T1 + 0.05 (1)
0.15 ≦ T1 ≦ 0.30 (2)
The above relational expression (1) indicates a condition in which a crack is not generated on the side wall of the battery case before the valve element is operated and the high temperature gas is released from the sealing plate. Moreover, relational expression (2) shows the conditions which satisfy | fill the sealing intensity | strength at the time of caulking the sealing part of a battery case, and workability. That is, if the thickness T1 of the sealing portion of the battery case is less than 0.15 mm, the sealing strength is insufficient, and the caulking portion may be loosened before the valve element is activated, and the sealing plate may come off and jump out. In addition, if the thickness T1 of the sealing portion of the battery case is larger than 0.30 mm, a large force is required for the caulking sealing, and the equipment needs to be enlarged, which is economically disadvantageous.
　なお、上記の関係式（１）は、電池ケースの側壁に亀裂が発生する前に、封口板が飛散する現象、及び、電池ケースの側壁に亀裂が発生せず、かつ、封口板が飛散しない現象の両方を含む。すなわち、本発明は、電池ケースの側壁に亀裂を発生させないことを前提に、最悪の場合でも、封口板を飛散させることにより、電池ケースの側壁に亀裂が発生するのを抑制するものである。 The above relational expression (1) indicates that the sealing plate scatters before the side wall of the battery case is cracked, and that the side wall of the battery case does not crack and the sealing plate does not scatter. Includes both phenomena. That is, the present invention suppresses the occurrence of cracks in the side walls of the battery case by scattering the sealing plate even in the worst case, assuming that no cracks are generated in the side walls of the battery case.
　以上、本発明を好適な実施形態により説明してきたが、こうした記述は限定事項ではなく、勿論、種々の改変が可能である。例えば、上記実施例では、正極活物質に、ＬｉＮｉ0.8Ｃｏ0.15Ａｌ0.05Ｏ2を用いたが、これに限定されず、一般式ＬｉｘＮｉｙＭ１－ｙＯ２（ｘ：０．９５≦ｘ≦１．１５、０．６≦ｙ≦１、ＭはＣｏ、Ｍｎ、Ｃｒ、Ｆｅ、Ｗ、Ｍｇ、Ｚｒ、ＴｉおよびＡｌの少なくとも１種類）で表されるリチウムニッケル複合酸化物を用いることができる。また、上記実施例では、体積エネルギー密度が７００Ｗｈ／Ｌのリチウムイオン二次電池の例を説明したが、これに限定されず、体積エネルギー密度が６００Ｗｈ／Ｌ以上のリチウムイオン二次電池に、好適に適用できる。また、上記の実施形態では、リチウムイオン二次電池を例に説明したが、これに限らず、他の非水電解質二次電池や、アルカリ蓄電池等にも適用できる。 As mentioned above, although this invention was demonstrated by suitable embodiment, such description is not a limitation matter and of course various modifications are possible. For example, in the above embodiment, LiNi 0.8 Co 0.15 Al 0.05 O 2 was used as the positive electrode active material. However, the present invention is not limited to this, and the general formula Li x Ni y M 1-y O 2 (x: 0.95 ≦ x ≦ 1.15, 0.6 ≦ y ≦ 1, and M is a lithium nickel composite oxide represented by Co, Mn, Cr, Fe, W, Mg, Zr, Ti, and Al) Can do. Moreover, in the said Example, although the example of the lithium ion secondary battery whose volume energy density is 700 Wh / L was demonstrated, it is not limited to this, It is suitable for a lithium ion secondary battery whose volume energy density is 600 Wh / L or more. Applicable to. In the above-described embodiment, the lithium ion secondary battery has been described as an example. However, the present invention is not limited to this, and can be applied to other nonaqueous electrolyte secondary batteries, alkaline storage batteries, and the like.
　本発明の密閉型電池は、携帯電話やノート型パソコン等の民生用モバイルツールの主電源、電動ドライバー等のパワーツールの主電源、およびＥＶ自動車等の産業用主電源の用途に適している。 The sealed battery of the present invention is suitable for use as a main power source for consumer mobile tools such as mobile phones and laptop computers, a main power source for power tools such as an electric screwdriver, and an industrial main power source such as an EV car.
　　１　　正極板
　　２　　負極板
　　３　　セパレータ
　　４　　電極群
　　５　　電池ケース
　　５ａ　溝部
　　５ｂ　封口部
　　５ｃ　側壁
　　６　　上部絶縁板
　　７　　負極リード
　　８　　正極リード
　　９　　下部絶縁板
　　１０　封口板
　　１１　ガスケット
　　１５　溝
　　２０　電池 DESCRIPTION OF SYMBOLS 1 Positive electrode plate 2 Negative electrode plate 3 Separator 4 Electrode group 5 Battery case 5a Groove part 5b Sealing part 5c Side wall 6 Upper insulating board 7 Negative electrode lead 8 Positive electrode lead 9 Lower insulating board 10 Sealing board 11 Gasket 15 Groove 20 Battery

Claims (5)

  1. 　発電要素が電解質とともに電池ケースに収容された密閉型電池であって、
    　前記電池ケースは、該電池ケースの封口部において、封口板によってかしめ封口されており、
    　前記電池ケースの封口部の厚みをＴ１（ｍｍ）、前記電池ケースの側壁の厚みをＴ２（ｍｍ）としたとき、Ｔ１及びＴ２が、以下の関係式（１）及び（２）を満たす、密閉型電池。
    　　Ｔ２≧０．８８Ｔ１＋０．０５・・・・（１）
    　　０．１５≦Ｔ１≦０．３０　　・・・・（２）     A power generation element is a sealed battery housed in a battery case together with an electrolyte,
    The battery case is caulked and sealed by a sealing plate at the sealing part of the battery case,
    When the thickness of the sealing portion of the battery case is T1 (mm) and the thickness of the side wall of the battery case is T2 (mm), T1 and T2 satisfy the following relational expressions (1) and (2). Type battery.
    T2 ≧ 0.88T1 + 0.05 (1)
    0.15 ≦ T1 ≦ 0.30 (2)
  2. 　前記電池ケースの底面に、該電池ケース内の圧力の増加によって破断する溝が形成されている、請求項１に記載の密閉型電池。 The sealed battery according to claim 1, wherein a groove that is broken by an increase in pressure in the battery case is formed on a bottom surface of the battery case.
  3. 前記電池は、リチウムイオン二次電池である、請求項１または２に記載の密閉型電池。 The sealed battery according to claim 1, wherein the battery is a lithium ion secondary battery.
  4. 　前記リチウムイオン二次電池は、正極活物質が一般式ＬｉｘＮｉｙＭ１－ｙＯ２（ｘ：０．９５≦ｘ≦１．１５、０．６≦ｙ≦１、ＭはＣｏ、Ｍｎ、Ｃｒ、Ｆｅ、Ｗ、Ｍｇ、Ｚｒ、ＴｉおよびＡｌの少なくとも１種類）で表されるリチウムニッケル複合酸化物である、請求項３に記載の密閉型電池。 In the lithium ion secondary battery, the positive electrode active material is represented by the general formula Li x Ni y M 1-y O 2 (x: 0.95 ≦ x ≦ 1.15, 0.6 ≦ y ≦ 1, M is Co, Mn , Cr, Fe, W, Mg, Zr, Ti, and Al).
  5. 　前記リチウムイオン二次電池は、体積エネルギー密度が６００Ｗｈ／Ｌ以上である、請求項３または４に記載の密閉型電池。 The sealed battery according to claim 3 or 4, wherein the lithium ion secondary battery has a volume energy density of 600 Wh / L or more.
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WO2017051514A1 (en) * 2015-09-25 2017-03-30 三洋電機株式会社 Cylindrical nonaqueous electrolyte secondary battery
CN112335100A (en) * 2018-06-21 2021-02-05 松下知识产权经营株式会社 Battery with a battery cell
EP4148880A1 (en) * 2021-09-10 2023-03-15 Shenzhen Hairun New Energy Technology Co., Ltd. Casing for battery and battery

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WO2016121319A1 (en) * 2015-01-30 2016-08-04 三洋電機株式会社 Cylindrical nonaqueous electrolyte secondary battery
WO2017051514A1 (en) * 2015-09-25 2017-03-30 三洋電機株式会社 Cylindrical nonaqueous electrolyte secondary battery
CN112335100A (en) * 2018-06-21 2021-02-05 松下知识产权经营株式会社 Battery with a battery cell
CN112335100B (en) * 2018-06-21 2022-08-26 松下知识产权经营株式会社 Battery with a battery cell
EP4148880A1 (en) * 2021-09-10 2023-03-15 Shenzhen Hairun New Energy Technology Co., Ltd. Casing for battery and battery

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