JP2011060644A - Sealed battery and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealed battery preventing corrosion such as rust. <P>SOLUTION: The sealed battery includes a battery container 10 having an opening part 50 on at least one end, and a sealing body 20 for sealing the opening part 50 of the battery container 10. The battery container 10 is constituted of a plate member 40 having a steel plate 44, and metal plating layers 42a, 42b coating both surfaces of the steel plate 44. A molten alloy part 46 formed by melting and alloying the steel plate 44 and the metal plating layers 42q, 42b is formed on a non-coated part which is a tip end surface 18 of the plate member 40 forming the opening part 50 of the battery container 10 and is not coated with the metal plating layers 42a, 42b. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a sealed battery including a battery container having an opening, and a sealing body that seals the opening of the battery container, and a method for manufacturing the same.

  In recent years, lithium-ion batteries, nickel-metal hydride batteries, and other secondary batteries have become increasingly important as power sources for vehicles or as power sources for personal computers and portable terminals. In particular, a lithium ion battery that is lightweight and obtains a high energy density is expected to be preferably used as a high-output power source mounted on a vehicle.

  In one aspect of the lithium ion battery, an electrode body, an electrolytic solution, and the like are accommodated in a metal battery container, and a metal lid body is attached to the opening of the battery container and sealed. As a prior art regarding sealing of the opening part of a battery container, patent documents 1-5 are mentioned, for example.

  As one of such sealing methods, it has been studied that the sealing body is joined to the battery container by a caulking process. FIG. 11 shows an example of a battery structure in which a sealing body is fixed by crimping to an opening of a battery container. In the example of FIG. 11, the sealing body 120 is disposed in the opening 150 of the battery container 110 via the resin gasket 130, and the opening end 112 of the battery container is crimped to the peripheral edge 122 of the sealing body together with the gasket 130. Thus, the opening 150 of the battery container 110 is sealed.

Japanese Patent Laid-Open No. 11-307064 JP 2002-298793 A Japanese Patent Publication No. 7-93128 Japanese Patent Laid-Open No. 5-109393 JP 2004-220863 A

  By the way, as one of the battery containers for this type of lithium ion battery, a nickel-plated steel sheet (surface-treated steel sheet) is used as a raw material, and the surface-treated steel sheet is drawn or trimmed into a bottomed cylindrical shape. The formed one is used. Such a battery container is produced, for example, by cutting a flat surface-treated steel plate to produce a circular blank, and forming the circular blank into a bottomed cylinder by drawing or the like.

  However, in the case of a battery container using a surface-treated steel sheet, when producing a bottomed cylindrical battery container from a flat surface-treated steel sheet, a part of the steel plate base material is exposed from the nickel plating, and this exposed part is rusted. Corrosion such as that may occur. Specifically, when a circular blank is cut out from a flat surface-treated steel plate, nickel plating is not present at the end portion (blank end surface) where the circular blank is cut, and the steel plate base material is exposed. When this circular blank is formed into a bottomed cylindrical shape by drawing, there is no nickel plating on the open end surface of the formed battery container, and the steel plate base material is exposed. When a sealing structure as shown in FIG. 11 is constructed using such a battery container, the nickel plating 142a, 142b does not exist on the front end surface 118 of the open end 112 of the battery container 110 subjected to the crimping process. The underlying steel plate 144 is exposed. There is a problem that corrosion such as rust occurs in the exposed portion, and problems such as hole opening and sealing failure occur.

  This invention is made | formed in view of this point, The main objective is to provide the sealed battery which can prevent corrosion, such as rust. Another object is to provide a method of manufacturing a sealed battery having such performance.

  The sealed battery provided by the present invention is a sealed battery including a battery container having an opening at at least one end and a sealing body that seals the opening of the battery container. The said battery container is comprised with the board | plate material which has a steel plate and the metal plating layer which coat | covers both surfaces of this steel plate. Then, a molten alloy portion formed by melt-alloying the steel plate and the metal plating layer is formed on the uncovered portion not covered with the metal plating layer on the front end surface of the plate material forming the opening of the battery container. It is characterized by being.

  According to this configuration, the front end surface of the plate material forming the opening of the battery container is more resistant to corrosion than the steel plate in the non-covered portion that is not covered with the metal plating layer (that is, the rusted portion where the steel plate base material is exposed). Since a high melting alloy part is formed, it is possible to prevent corrosion such as rust from occurring on the front end surface of the plate material, and it is possible to suppress perforation or sealing failure. Thereby, a highly airtight sealing structure can be maintained over a long period of time, and a highly reliable sealed battery can be provided.

  In a preferred aspect of the sealed battery disclosed herein, the opening of the battery container is sealed by crimping the opening end of the battery container on which the molten alloy portion is formed to the peripheral edge of the sealing body. Has been. According to this configuration, the progress of corrosion such as rust is suppressed at the opening end of the battery container that has been subjected to the crimping process, and the airtightness of the crimped part can be kept good. In addition, since the molten alloy part is integrated with the other part of the battery container (the part adjacent to the molten alloy part) by the fusion alloying of the steel plate and the metal plating layer, the molten alloy part is removed from the other part. Hard to peel off. Therefore, even if it is subjected to friction due to caulking treatment or deformation of the surface-treated steel sheet, the problem of the molten alloy part peeling off from the battery container (and thus exposing the underlying steel sheet) is avoided, and the rust prevention structure is appropriately set. Can keep.

  In a preferred embodiment of the sealed battery disclosed herein, the molten alloy part is formed by laser irradiation. By using laser irradiation, it is possible to easily and reliably form a molten alloy between a steel plate and a metal plating layer, and to form a molten alloy portion having excellent corrosion resistance.

  In a preferable aspect of the sealed battery disclosed herein, the metal plating layer contains at least one metal element of Ni, Zn, Cr, and Sn. The metal plating layer containing the metal element is preferably used as a metal plating layer suitable for the purpose of the present invention because it has higher corrosion resistance than a steel plate and can be alloyed with a steel plate.

  In a preferred embodiment of the sealed battery disclosed herein, the metal plating layer is a Ni plating layer. In this case, the content of Ni contained in the molten alloy part is preferably 0.05% by mass to 2% by mass with respect to the total mass of the molten alloy part. By setting it within this range, it is possible to form a molten alloy part having more excellent corrosion resistance. The Ni content can be calculated, for example, from the analysis result of mapping data by EPMA (electron probe microanalyzer).

  In a preferred embodiment of the sealed battery disclosed herein, a rust preventive agent is applied to the molten alloy part. By using a molten alloy part and a rust inhibitor in combination, the progress of corrosion such as rust can be more reliably prevented.

  In a preferred embodiment of the sealed battery disclosed herein, the outer surface of the open end portion of the crimped battery container is covered with a resin exterior film. By covering the outer surface of the open end of the battery container that has been subjected to the crimping process with an exterior film, intrusion of moisture and the like can be suppressed, and the progress of corrosion such as rust can be more reliably prevented.

  Moreover, this invention provides the manufacturing method of the sealed battery which can manufacture preferably the sealed battery which has the said performance. This method includes a step of forming a surface-treated steel sheet in which both surfaces of a steel sheet are coated with a metal plating layer, and producing a battery container having an opening at at least one end. Then, the method includes a step of irradiating a tip end surface of the surface-treated steel sheet forming the opening of the molded battery container with a laser to form a molten alloy part formed by melting and alloying the metal plating layer and the steel sheet.

  According to this manufacturing method, a highly reliable sealed battery that can prevent corrosion such as rust can be manufactured. That is, when producing the battery container from the surface-treated steel sheet, when the surface-treated steel sheet is formed (for example, blank cutting, drawing, trimming, etc.), the front end surface of the plate material that forms the opening of the formed battery container The steel plate base material is exposed. If this exposed part is left as it is, corrosion such as rust may occur in the exposed part. However, according to the present invention, the tip surface of the plate material on which the steel plate base material is exposed is irradiated with a laser to be more resistant to corrosion than the steel plate. Therefore, the progress of corrosion such as rust is suppressed, and a highly reliable sealed battery can be manufactured.

  In a preferred embodiment of the sealed battery disclosed herein, after forming the molten alloy portion, the opening end portion of the battery container in which the molten alloy portion is formed is crimped to the peripheral portion of the sealing body, A step of sealing the opening of the battery case. According to this method, it is possible to manufacture a sealed battery in which the caulking portion is kept airtight. Further, since the molten alloy part is integrated with the battery container by forming a molten alloy between the steel plate and the metal plating layer by laser irradiation, the molten alloy part is hardly peeled off from the battery container. Therefore, the problem that the molten alloy part is peeled off from the battery container due to friction of the caulking process or the like can be avoided, and the caulking process can be performed stably.

  The present invention also provides a vehicle including the sealed battery or the sealed battery manufactured by the manufacturing method. In a sealed battery for mounting on a vehicle, the battery container is often used under severe conditions for a long period of time (for example, a place where temperature change is likely to cause condensation), and the airtightness of the battery container may be reduced due to corrosion such as rust. According to the configuration of the present invention, the hermetically sealed battery suitable for mounting on a vehicle can be provided because high hermeticity is maintained even after long-term use due to the configuration of the molten alloy portion.

1 is a side view schematically showing a sealed battery according to an embodiment of the present invention. It is sectional drawing which shows the II-II cross section of FIG. 1 typically. It is the cross-sectional schematic diagram which expanded the principal part of the sealed battery which concerns on one Embodiment of this invention. It is the cross-sectional schematic diagram which expanded the principal part of the sealed battery which concerns on one Embodiment of this invention. It is a figure for demonstrating the process of the laser irradiation which concerns on one Embodiment of this invention. It is a mapping which shows the cut end surface of the comparative blank after a dew cycle test. It is a mapping which shows the cut end surface of the blank for a test after a dew condensation cycle test. It is a figure for demonstrating the winding electrode body which concerns on one Embodiment of this invention. It is the cross-sectional schematic diagram which expanded the principal part of the sealed battery which concerns on other embodiment of this invention. 1 is a schematic side view of a vehicle equipped with a sealed battery according to an embodiment of the present invention. It is a cross-sectional schematic diagram which shows the sealing structure of the conventional battery container opening part.

  Embodiments according to the present invention will be described below with reference to the drawings. In addition, matters other than matters specifically mentioned in the present specification and matters necessary for carrying out the present invention (for example, the configuration and manufacturing method of an electrode body including a positive electrode and a negative electrode, the configuration and manufacturing method of a separator and an electrolyte, General techniques relating to the construction of lithium secondary batteries and other batteries, etc.) can be understood as design matters for those skilled in the art based on the prior art in this field. In the following drawings, members / parts having the same action are denoted by the same reference numerals, and redundant description may be omitted or simplified. The dimensional relationship (length, width, thickness, etc.) in each figure does not reflect the actual dimensional relationship.

  Although not intended to be particularly limited, an example of a sealed lithium ion battery having a configuration in which a wound electrode body (wound electrode body) and a nonaqueous electrolyte solution are housed in a cylindrical battery container will be described below. The present invention will be described in detail.

  As shown in FIGS. 1 to 3, the lithium ion battery 100 according to this embodiment includes a battery container 10 having an opening 50 at least at one end, a sealing body 20 that seals the opening 50, and a gasket 30. Prepare.

  The battery container 10 is formed in a bottomed cylindrical shape having an opening 50 at one end. The negative electrode 84 of the wound electrode body 80 is electrically connected to the bottom surface 74 of the battery container 10 via the negative electrode current collecting terminal 78, and the battery container 10 also serves as the negative electrode terminal. On the inner surface of the battery case 10, an annular convex portion 14 for attaching the sealing body 20 to the opening is formed over the entire circumference. In the battery container 10, for example, a long sheet-like positive electrode (positive electrode sheet) 82 and a long sheet-like negative electrode (negative electrode sheet) 84 are laminated together with a total of two long sheet-like separators (separator sheets). A wound electrode body 80 to be wound is accommodated together with an electrolyte solution (not shown).

  As shown in FIG. 3, the battery container 10 includes a plate member 40 having a steel plate 44 and metal plating layers 42 a and 42 b covering both surfaces of the steel plate 44. The metal plating layers 42a and 42b have a function of preventing corrosion such as rust from occurring on the steel plate. The metal constituting the metal plating layer preferably has higher corrosion resistance than the steel plate and can be alloyed with the steel plate. For example, a material containing at least one metal among Ni, Zn, Cr, and Sn can be preferably used. In this embodiment, the metal plating layer is a Ni plating layer.

  Further, a molten alloy portion 46 is formed in an uncovered portion that is not covered with the metal plating layer on the front end surface 18 of the plate member 40 that forms the opening 50 of the battery container. The molten alloy portion 46 is formed by melting and alloying the steel plate 44 and the metal plating layers 42a and 42b. In this embodiment, the metal plating layers 42a and 42b are Ni plating layers, and the molten alloy portion 46 is made of a Ni—Fe alloy obtained by melting and alloying the NI plating layer and the steel plate. The molten alloy portion 46 is excellent in corrosion resistance (particularly rust resistance) and is less likely to be corroded than the steel plate 44.

  The sealing body 20 is for sealing the opening part 50 of the battery container 10, and is formed in the circular shape suitable for the opening shape of a battery container. In this embodiment, a positive electrode terminal 72 that is electrically connected to the positive electrode 82 of the wound electrode body 80 via the positive electrode current collector terminal 76 is attached to the upper surface of the sealing body 20. As a material which comprises the sealing body 20, the thing similar to what is used with a general lithium ion battery can be used suitably, and there is no restriction | limiting in particular. From the viewpoint of heat dissipation and the like, a metal (for example, aluminum) sealing body 20 can be preferably used. The sealing body 20 of this embodiment is made of aluminum.

  The gasket 30 is disposed between the peripheral edge portion 22 of the sealing body and the inner peripheral surface of the battery container 10. The gasket 30 has a groove 32 that can be fitted to the peripheral edge 22 of the sealing body 20, and the sealing body 20 is fitted in the groove 32. The constituent material of the gasket 30 is not particularly limited as long as it can exhibit a desired sealing property (for example, performance of preventing moisture intrusion). An elastic material having good resistance to the electrolytic solution used in the battery is preferable. For example, an elastic material having high resistance to organic solvents such as ethylene-propylene rubber (EPM), ethylene-propylene-diene copolymer rubber (EPDM), fluorine rubber (for example, vinylidene fluoride (FKM)), butyl rubber, etc. is preferable. Can be adopted. The gasket 30 of this embodiment is made of EPDM.

  In the present embodiment, as shown in FIG. 3, the opening 50 of the battery container is sealed by crimping the opening end 12 of the battery container in which the molten alloy portion 46 is formed to the peripheral edge 22 of the sealing body 20. ing. In FIG. 3, the shape of the open end 12 of the battery container before the caulking process is indicated by a two-dot chain line. In this embodiment, the annular convex part 14 for attaching the sealing body 20 is formed in the inner peripheral surface of the battery container 10, and the sealing body 20 is arrange | positioned through the gasket 30 on the upper surface 14a of the annular convex part. In that state, the opening end 12 of the battery container is bent inward and crimped to the peripheral edge 22 of the sealing body 20 together with the gasket 30 to fix the sealing body 20 to the battery container 10 and to seal the sealing body. Gasket 30 is compressed between 20 and battery container 10 to seal opening 50.

  According to the sealed battery 100 of the present embodiment, the uncovered portion (that is, the steel plate base material 44) that is not covered with the metal plating layers 42a and 42b on the tip surface 18 of the plate member 40 that forms the opening 50 of the battery container 10 is provided. Since the molten alloy portion 46 having higher corrosion resistance than that of the steel plate is formed in the exposed rust-prone portion), it is possible to prevent corrosion such as rust on the front end surface 18 of the plate material 40, and to make a hole or seal failure. Etc. can be suppressed. Thereby, a highly airtight sealing structure can be maintained over a long period of time, and a highly reliable sealed battery 100 can be provided.

  Moreover, in this embodiment, the opening part 50 of a battery container is sealed by crimping the opening edge part 12 of the battery container which has the molten alloy part 46 to the peripheral part 22 of a sealing body. According to such a configuration, the progress of corrosion such as rust is suppressed at the opening end 12 of the battery container that has been subjected to the crimping process, and the airtightness of the crimped part can be kept good. Moreover, since the molten alloy part 46 is integrated with the other part of the battery container 10 by forming a molten alloy of the steel plate and the metal plating layer, the molten alloy part 46 is hardly peeled off from the battery container 10. Therefore, the problem that the molten alloy portion 46 is peeled off from the battery container 10 due to friction of the caulking process (and the underlying steel plate 44 is exposed) can be avoided, and the rust prevention structure can be appropriately maintained.

  Exemplifying the dimensions of the steel plate and the metal plating layer, the thickness of the steel plate 44 is, for example, about 0.1 mm to 2.0 mm, and usually about 0.3 mm to 1.0 mm (here 0.3 mm). . The thickness of the metal plating layers 42a and 42b is, for example, about 1 μm to 20 μm, and usually about 3 μm to 10 μm (here, 3 μm). Moreover, the thickness of the molten alloy part 46 formed in the front end surface 18 of an opening edge part should just be a thickness of the grade which a steel plate does not expose from a molten alloy part, for example, is about 0.1 mm-2.0 mm, and is normal. Is preferably about 0.3 mm to 1.0 mm (here 0.5 mm).

  Further, the content of Ni contained in the molten alloy part 46 is not particularly limited, but if the Ni content is too small, the corrosion resistance effect may not be sufficiently obtained, and if the Ni content is too large. When melted, it is difficult to melt evenly and may be easily separated. Therefore, the content of Ni in the molten alloy part may be approximately 0.05% by mass to 2% by mass with respect to the total mass of the molten alloy part, and usually 0.1% by mass to 0.3% by mass. It is preferable that By making it within this range, it is possible to obtain a molten alloy part which is more resistant to corrosion and has a higher corrosion resistance. The content of Ni in the molten alloy part can be calculated, for example, from the analysis result of mapping data by EPMA (electron beam probe microanalyzer).

  Then, the manufacturing method of the lithium ion battery 100 provided with the said structure is demonstrated.

  First, a surface-treated steel sheet in which both surfaces of the steel sheet 44 are coated with metal plating layers (here, Ni plating layers) 42a and 42b is formed to produce a battery container having an opening 50 at least at one end. In this embodiment, a flat surface-treated steel sheet is prepared (purchased or manufactured). Then, the flat surface-treated steel sheet is cut to produce a circular blank, and the circular blank is formed into a bottomed cylindrical can body by drawing or the like. Then, a bottomed cylindrical battery container is manufactured by trimming the shape of the opening of the can body (for example, removing burrs or the like generated at the opening end 12).

  Here, when a bottomed cylindrical battery container is produced from a flat surface-treated steel sheet, a part of the steel sheet 44 is exposed from the Ni plating layers 42a and 42b. Specifically, when a circular blank is cut out from a flat surface-treated steel plate, the Ni plating layer does not exist at the end (blank end surface) where the circular blank is cut, and the steel plate is exposed. When this circular blank is formed into a bottomed cylindrical shape by drawing, Ni plating layers 42a and 42b are present on the front end surface 18 of the plate 40 forming the opening 50 of the molded battery container, as shown in FIG. Instead, the steel plate 44 is exposed. In the present embodiment, the molten alloy portion 46 is formed on the exposed portion (that is, the tip surface 18 of the plate material (surface-treated steel plate) 40 not covered with the Ni plating layer).

  That is, as shown in FIG. 5, a molten alloy portion formed by irradiating the tip surface 18 of the plate member 40 forming the opening 50 of the molded battery container with a laser 52 to melt the Ni plating layer and the steel plate. 46 is formed. In this embodiment, the laser 52 is irradiated over the entire circumference of the front end surface 18 of the plate material forming the opening 50. By this laser irradiation, the peripheral portion including the front end surface 18 is in a molten state, and a molten alloy portion 46 made of a Ni—Fe alloy is formed. The type of laser used for laser irradiation is not particularly limited as long as it can melt-metallize the metal plating layer and the steel plate. For example, a solid-state laser such as a YAG laser or a gas laser such as a carbon dioxide gas laser can be preferably used.

  The surface-treated steel plate (steel plate and Ni plating layer) irradiated with the laser is desirably one in which the Ni plating layer and the steel plate are firmly adhered. By using such a surface-treated steel sheet, it becomes difficult to form a diffusion layer upon melting from the Ni—Fe molten state. Therefore, an appropriate amount of Ni can be contained in the molten alloy part, and a molten alloy part having excellent corrosion resistance can be formed. Such a surface-treated steel sheet can be formed, for example, by subjecting both surfaces of a steel sheet base material to electrolytic Ni plating, and then performing a temper rolling process for adjusting the surface roughness.

  After forming the molten alloy part, next, the electrode body 80 is accommodated in the battery container 10, and the annular recess 16 is formed on the entire outer surface of the battery container 10. Thereby, the annular convex part 14 for attaching the sealing body 20 to the inner peripheral surface of the battery container 10 is formed. The method of forming the annular recess 16 is not particularly limited, and for example, a method of pressing a pressing member having a curved surface formed in an arc shape on the outer surface of the battery container 10 may be appropriately employed.

Next, the sealing body 20 is disposed in the opening 50 of the battery container, and the opening end 12 of the battery container in which the molten alloy part 46 is formed is crimped to the peripheral edge 22 of the sealing body, thereby opening the opening 50 of the battery container. To seal. In this embodiment, as shown in FIG. 3, the sealing body 20 is disposed on the annular convex portion 14 provided on the inner peripheral surface of the battery container 10 via the gasket 30. In FIG. 3, the shape of the open end 12 of the battery container before the caulking process is indicated by a two-dot chain line. The opening end portion 12 where the molten alloy portion 46 is formed is bent inward over the entire circumference, and crimped to the peripheral edge portion 22 of the sealing body 20 together with the gasket 30. By this caulking process, the gasket 30 is brought into close contact with the battery container 10 and the sealing body 20, the sealing body 20 is fixed to the battery container 10, and the gasket 30 is compressed between the sealing body 20 and the battery container 10 to be opened. The part 50 is sealed.
In this way, the lithium ion battery (sealed battery) 100 according to the present embodiment can be manufactured.

  According to the manufacturing method of the present embodiment, it is possible to manufacture a highly reliable sealed battery 100 that can prevent corrosion such as rust at the opening end 12 of the battery container. That is, when forming the battery case 10 from the surface-treated steel sheet, when the surface-treated steel sheet is formed (for example, blank cutting, drawing, trimming, etc.), as shown in FIG. The steel plate base material 44 is exposed at the front end surface 18 of the plate material 40 forming the portion 50. If this exposed portion is left as it is, corrosion such as rust may occur in the exposed portion. However, according to the present embodiment, as shown in FIG. 5, the front end surface of the plate 40 where the steel plate base material 44 is exposed. 18 is irradiated with the laser 52 to form the molten alloy portion 46 having higher corrosion resistance than that of the steel plate, and thus the progress of corrosion such as rust is suppressed, and the highly reliable sealed battery 100 can be manufactured.

  Further, in this embodiment, after the molten alloy portion 46 is formed, the opening portion 12 of the battery container having the molten alloy portion 46 is crimped to the peripheral edge portion 22 of the sealing body to seal the opening portion 50 of the battery container. To do. According to this method, it is possible to manufacture a sealed battery in which the caulking portion is kept airtight. Moreover, since the molten alloy part 46 is integrated with the battery container 10 by forming a molten alloy between the steel plate and the metal plating layer by laser irradiation, the molten alloy part 46 is difficult to peel off from the battery container 10. Therefore, a problem that the molten alloy portion 46 is peeled off from the battery container 10 due to friction of the caulking process or the like is avoided, and the caulking process can be performed stably.

  Next, in order to confirm that the progress of corrosion such as rust is suppressed by forming the molten alloy portion 46 on the front end surface 18 of the plate material forming the opening of the battery container, the following experiment is conducted as a test example. Went. That is, a flat surface-treated steel sheet (commercial product) in which both surfaces of a steel sheet (thickness 0.3 mm) are coated with a Ni plating layer (thickness 3 μm) is prepared, and the surface-treated steel sheet is cut into a plurality of pieces and tested. Was cut out. And the YAG laser was irradiated to the cutting end surface of the test blank which exposed the steel plate, and the molten alloy part was formed in the cutting end surface. YAG laser irradiation conditions were set such that the oscillation wavelength was 1.06 μm, the pulse oscillation output was 0.1 kW to 4 kW (peak), the pulse width was 0.2 ms to 2 ms, and the laser irradiation diameter was 800 μm.

  A dew cycle test was performed on the test blank after the laser irradiation. Specifically, after holding the test blank for 1.5 hours in a low temperature environment of −20 ° C., the test blank is held for 0.5 hours in a high temperature and high humidity environment of temperature 20 ° C. and humidity 80%, Condensation was caused on the test blank. Then, it dehumidified over 1 hour at the temperature of 20 degreeC, and the blank for a test was dried. Then, by alternately applying low temperature and high temperature and high humidity, condensation and drying were repeated, and the occurrence of rust on the test blank after 30 cycles was evaluated. For comparison, a comparative blank in which a molten alloy part was not formed on the cut end face of the blank was produced, and a dew cycle test was performed. The dew condensation cycle test for comparison was performed in the same manner as the test blank.

  The results are shown in FIGS. FIG. 6 is a map showing the cut end face of the comparative blank after the condensation cycle test, and FIG. 7 is a map showing the cut end face of the test blank after the condensation cycle test. As shown in FIG. 6, a large amount of rust was generated and the corrosion progressed on the cut end surface of the comparative blank where the underlying steel plate was exposed, whereas, as shown in FIG. It was found that almost no rust was observed on the cut end face of the formed test blank, and the progress of corrosion was suppressed. From this, it was confirmed that the progress of corrosion such as rust is suppressed by forming the molten alloy portion 46 on the front end face 18 of the plate material forming the opening 50 of the battery container.

  In addition, there is no restriction | limiting in particular about the structure (for example, winding structure or laminated structure) of the electrode body accommodated in the battery case 10 of this embodiment, the kind of electrolyte solution, etc. Hereinafter, an example of an electrode body and an electrolytic solution housed in the battery container 10 will be described with reference to the schematic diagram shown in FIG.

  As shown in FIGS. 1 to 3, the lithium ion battery 100 according to this embodiment includes a battery container 10 having an opening 50 at least at one end, and a sealing body 20 that seals the opening 50. The sealing body 20 is provided with a positive electrode terminal 72 that is electrically connected to the positive electrode of the wound electrode body 80. In addition, a negative electrode terminal 74 that is electrically connected to the negative electrode of the wound electrode body 80 is provided on the bottom surface of the battery container 10. Inside the battery container 10, a wound electrode body 80 is accommodated together with a non-aqueous electrolyte (not shown).

  Each of the positive electrode sheet 82 and the negative electrode sheet 84 has a configuration in which an electrode mixture layer mainly composed of an electrode active material is provided on both surfaces of a long sheet-like electrode current collector. At one end in the width direction of the electrode sheets 82 and 84, an electrode mixture layer non-formed portion where the electrode mixture layer is not provided on any surface is formed. In the lamination, the positive electrode sheet 82 and the negative electrode mixture layer non-formed portion of the negative electrode sheet 84 protrude from both sides of the separator sheet 60 in the width direction, The negative electrode sheet 84 is overlaid with a slight shift in the width direction. As a result, in the lateral direction with respect to the winding direction of the wound electrode body 80, the electrode mixture layer non-forming portions of the positive electrode sheet 82 and the negative electrode sheet 84 are respectively wound core portions (that is, the positive electrode mixture layer forming portion of the positive electrode sheet 82). And a portion where the negative electrode mixture layer forming portion of the negative electrode sheet 84 and the two separator sheets 60 are wound tightly). A positive electrode current collector terminal 76 and a negative electrode current collector terminal 78 are attached to the positive electrode side protruding portion (that is, the non-formed portion of the positive electrode mixture layer) and the negative electrode side protrusion portion (that is, the non-formed portion of the negative electrode mixture layer), respectively. Are electrically connected to the positive terminal 72 and the negative terminal 74 described above.

  The wound electrode body 80 according to the present embodiment is the same as the wound electrode body of a normal lithium ion battery, and has a long shape (band shape) before the wound electrode body 80 is assembled as shown in FIG. The sheet structure is as follows.

  The positive electrode sheet 82 has a structure in which a positive electrode mixture layer 83b containing a positive electrode active material is held on both surfaces of a long sheet-like foil-shaped positive electrode current collector 83a. However, the positive electrode mixture layer 83b is not attached to one side edge (upper side edge portion in the figure) along the widthwise end of the positive electrode sheet 82, and the positive electrode current collector 83a is exposed with a certain width. The formed positive electrode mixture layer non-formed part is formed.

  Similarly to the positive electrode sheet 82, the negative electrode sheet 84 has a structure in which a negative electrode mixture layer 85 b containing a negative electrode active material is held on both surfaces of a long sheet-like foil-shaped negative electrode current collector 85 a. However, the negative electrode mixture layer 85b is not attached to one side edge (the lower side edge portion in the figure) along the edge in the width direction of the negative electrode sheet 84, and the negative electrode current collector 85a has a constant width. An exposed negative electrode composite material layer non-forming portion is formed.

  In producing the wound electrode body 80, the positive electrode sheet 82 and the negative electrode sheet 84 are laminated via the separator sheet 60. At this time, the positive electrode sheet 82 and the negative electrode sheet 84 are formed such that the positive electrode mixture layer non-formed portion of the positive electrode sheet 82 and the negative electrode mixture layer non-formed portion of the negative electrode sheet 84 protrude from both sides in the width direction of the separator sheet 60. Are overlapped slightly in the width direction. The wound electrode body 80 can be manufactured by winding the laminated body thus superposed.

  A wound core portion (that is, the positive electrode mixture layer 83b of the positive electrode sheet 82, the negative electrode mixture layer 85b of the negative electrode sheet 84, and the separator sheet 60 are densely laminated at the central portion of the wound electrode body 80 in the winding axis direction. Part) is formed. Further, at both ends of the wound electrode body 80 in the winding axis direction, the electrode mixture layer non-formed portions of the positive electrode sheet 82 and the negative electrode sheet 84 protrude outward from the wound core portion, respectively. A positive electrode current collector terminal 76 and a negative electrode current collector terminal 78 are provided on the positive electrode side protruding portion (that is, the non-formed portion of the positive electrode mixture layer 83b) and the negative electrode side protrusion portion (that is, the non-formed portion of the negative electrode mixture layer 85b), respectively. Attached and electrically connected to the above-described positive electrode terminal 72 and negative electrode terminal 74 (also serving as the battery case 10 here).

The constituent elements constituting the wound electrode body 80 may be the same as those of the conventional wound electrode body of a lithium ion battery, and are not particularly limited. For example, the positive electrode sheet 82 can be formed by applying a positive electrode active material layer for a lithium ion battery on a long positive electrode current collector. For the positive electrode current collector, an aluminum foil (this embodiment) or other metal foil suitable for the positive electrode is preferably used. As the positive electrode active material, one or more of materials conventionally used in lithium ion batteries can be used without any particular limitation. Preferable examples include LiMn ₂ O ₄ , LiCoO ₂ , LiNiO _{2 and the} like. On the other hand, the negative electrode sheet 84 can be formed by providing a negative electrode active material layer for a lithium ion battery on a long negative electrode current collector. For the negative electrode current collector, a copper foil (this embodiment) or other metal foil suitable for the negative electrode is preferably used. As the negative electrode active material, one or more of materials conventionally used in lithium ion batteries can be used without any particular limitation. Preferable examples include carbon-based materials such as graphite carbon and amorphous carbon, lithium-containing transition metal oxides and transition metal nitrides.

  In addition, as a suitable example of the separator sheet 60 used between the positive and negative electrode sheets 82 and 84, one made of a porous polyolefin-based resin can be cited. For example, a porous separator sheet made of synthetic resin (for example, made of polyolefin such as polyethylene) can be suitably used. When a solid electrolyte or a gel electrolyte is used as the electrolyte, a separator may not be necessary (that is, in this case, the electrolyte itself can function as a separator).

The wound electrode body 80 is accommodated in the container 10 from the upper end opening 50 of the battery container 10, and an appropriate liquid electrolyte or solid (or gel-like) electrolyte, here, an appropriate non-aqueous electrolyte (for example, LiPF ₆ or the like) A nonaqueous electrolytic solution such as a mixed solvent of diethyl carbonate and ethylene carbonate containing an appropriate amount of lithium salt (supporting salt) is placed (injected) in the battery container 10, and the opening is sealed with the sealing body 20. Then, the construction (assembly) of the lithium ion battery 100 according to the present embodiment is completed. The sealing process of the battery container 10 is as described above. The electrolyte arrangement (injection) process may be the same as that used in the manufacture of conventional lithium ion batteries, and does not characterize the present invention.

  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, the battery container 10 described above has a bottomed cylindrical shape and has an opening 50 at one end in the longitudinal direction, but is not limited thereto. For example, a bottomless cylindrical battery container 10 having openings at both ends (one end and the other end) in the longitudinal direction may be used. Further, the shape of the battery container 10 is not limited to a cylindrical shape, and various changes can be made. For example, a rectangular (substantially rectangular parallelepiped) battery container may be used. Moreover, although this embodiment demonstrated the case where the opening part of a battery container was sealed by the crimping process, a sealing means is not restricted to this. For example, the opening of the battery container can be sealed by welding (for example, laser welding of the battery container and the sealing body) or the like. Even in this case, when there is an uncoated portion that is not covered with the metal plating layer on the front end surface of the opening end portion of the battery container, corrosion such as rust is prevented by forming a molten alloy portion in the uncoated portion. be able to.

  The technology disclosed herein can be particularly preferably applied to a battery in which an opening of a battery container is sealed by a caulking process and the manufacturing thereof. By using the caulking process, the opening 50 of the battery container can be sealed at a higher speed than welding joining such as laser welding. In addition, no welding spatter or the like is generated, and foreign matter contamination is easy. Can be realized. Further, the molten alloy part 46 is integrated with the other part of the battery container (the part adjacent to the molten alloy part) by forming a molten alloy between the steel plate and the metal plating layer. Even if the battery container (surface-treated steel plate) is plastically deformed, the molten alloy portion 46 is difficult to peel off. Therefore, in a battery in which the opening of the battery container is sealed by caulking, it is particularly meaningful to apply the technique disclosed herein.

  The molten alloy part 46 according to this embodiment can also be used in combination with other corrosion resistance (rust prevention) means. For example, as shown in FIG. 9, a rust inhibitor 90 may be applied to the molten alloy portion 46 formed on the tip surface 18 of the open end 12 of the battery container that has been subjected to the crimping process. The rust preventive agent 90 may be composed of, for example, a highly corrosion-resistant resin material (for example, a hydrocarbon resin or an acrylic resin), an oil WAX component that does not transmit moisture, or the like. Thus, by using the molten alloy part 46 and the rust inhibitor 90 in combination, the progress of corrosion such as rust can be more reliably prevented. In the example shown in FIG. 9, the outer surface of the opening end 12 of the battery container is covered with a resin exterior film 92. In this example, the exterior film 92 is made of a polyolefin resin and is disposed so as to wrap around the front end surface 18 (the molten alloy portion 46) of the opening end portion 12. By covering the outer surface of the opening end 12 with the exterior film 92 so as to wrap the tip end surface 18 (molten alloy portion 46) of the opening end in this way, the tip end surface 18 (molten alloy portion 46) of the opening end is covered. Intrusion of moisture and the like is suppressed, and the progress of corrosion such as rust can be more reliably prevented.

  A sealed battery (typically a secondary battery, for example, a lithium ion battery) manufactured by applying the method according to the present invention is suitably used as a power source for a motor (electric motor) mounted on a vehicle such as an automobile. Can do. Therefore, for example, as schematically shown in FIG. 10, the present invention is a vehicle (typically, which includes such a battery 100 (which may be in the form of an assembled battery formed by connecting a plurality of such batteries 100 in series) as a power source. In particular, an automobile (in particular, a car equipped with an electric motor such as a hybrid car or an electric car) 1 is provided.

DESCRIPTION OF SYMBOLS 1 Vehicle 10 Battery container 12 Container opening end part 14 Annular convex part 14a Annular convex part upper surface 16 Annular concave part 18 End face 20 of container opening end part Sealing body 22 Sealing body peripheral part 30 Gasket 32 Groove part 40 Plate material (surface-treated steel plate)
42a, 42b Metal plating layer 44 Steel plate 46 Molten alloy part 50 Opening 60 Separator sheet 72 Positive electrode terminal 74 Negative electrode terminal 76 Positive electrode current collector terminal 78 Negative electrode current collector terminal 80 Winding electrode body 82 Positive electrode sheet 83a Positive electrode current collector 83b Positive electrode combination Material layer 84 Negative electrode sheet 85a Negative electrode current collector 85b Negative electrode composite material layer 90 Rust preventive agent 92 Exterior film 100 Lithium ion battery

Claims (12)

A sealed battery comprising a battery container having an opening at at least one end, and a sealing body for sealing the opening of the battery container,
The battery container is constituted by a plate material having a steel plate and a metal plating layer covering both surfaces of the steel plate,
A molten alloy part formed by melt-alloying the steel plate and the metal plating layer is formed on an uncovered portion that is not covered with the metal plating layer on the front end surface of the plate member that forms the opening of the battery container. A sealed battery.   2. The sealed battery according to claim 1, wherein the opening of the battery container is sealed by crimping an opening end of the battery container in which the molten alloy part is formed to a peripheral edge of the sealing body.   The sealed battery according to claim 1, wherein the molten alloy part is formed by laser irradiation.   4. The sealed battery according to claim 1, wherein the metal plating layer contains at least one metal element of Ni, Zn, Cr, and Sn. The metal plating layer is a Ni plating layer,
5. The sealed mold according to claim 1, wherein the content of Ni contained in the molten alloy part is 0.05% by mass to 2% by mass with respect to the total mass of the molten alloy part. battery.   The sealed battery according to claim 1, wherein a rust preventive agent is applied to the molten alloy part.   The sealed battery according to any one of claims 1 to 6, wherein an outer surface of the opening end of the battery container is covered with a resin exterior film. A method for producing a sealed battery comprising: a battery container having an opening at at least one end; and a sealing body for sealing the opening of the battery container,
The following steps:
Forming a surface-treated steel sheet having both surfaces of the steel sheet coated with a metal plating layer and producing a battery container having an opening at at least one end; and a tip of the surface-treated steel sheet forming the opening of the molded battery container Irradiating the surface with a laser to form a molten alloy portion formed by melting and alloying the metal plating layer and the steel plate;
A method for producing a sealed battery, comprising:   The method includes the step of, after forming the molten alloy portion, crimping the opening end portion of the battery container in which the molten alloy portion is formed to a peripheral portion of a sealing body to seal the opening portion of the battery container. 9. The production method according to 8.   The manufacturing method according to claim 8 or 9, wherein the metal plating layer contains at least one metal element of Ni, Zn, Cr, and Sn. The metal plating layer is a Ni plating layer,
11. The manufacturing method according to claim 8, wherein the content of Ni contained in the molten alloy part is 0.05% by mass to 2% by mass with respect to the total mass of the molten alloy part. .   A vehicle comprising the sealed battery according to any one of claims 1 to 7 or the sealed battery manufactured by the manufacturing method according to any one of claims 8 to 11.