JP2019075334A - Manufacturing method of battery case body - Google Patents

Abstract

To provide a manufacturing method of a battery case body of which thermal conductivity is improved.SOLUTION: A manufacturing method of a battery case body includes: a step of obtaining a coated foil 12, where a carbon particle layer 11 is formed partially on the surface 10a scheduled to be coated of an aluminum foil 10, by coating a part of the coating surface 10a scheduled to be coated of the aluminum foil 10 with a coating liquid 5 containing carbon particles 1 and a binder 2, followed by drying; a step of obtaining a laminate 15 by laminating a plurality of coated foils 12 and joining the plurality of coated foils 12 by heating the laminate 15 to obtain a blank 80 which is partly composed of a composite material 60 having aluminum and carbon particles 1 compounded with the remainder composed of aluminum; and a step of molding the blank 80 into a square cylinder with one end open and the other end closed by deforming the same plastically by pressing, followed by finish machining.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a method of manufacturing a battery case main body used in a rectangular battery case, and more specifically, it is a square tube having one end opened and the other end closed, and the one end opening is closed by a closing member. For example, the present invention relates to a method of manufacturing a battery case main body used as a rectangular battery case of a lithium ion secondary battery.

  In this specification and claims, the term "aluminum" includes aluminum alloys in addition to pure aluminum.

  Moreover, in this specification, the term "plate" also includes foil.

  Furthermore, in this specification, the direction perpendicular to the thickness direction of the plate is referred to as the plane direction of the plate.

  Lithium ion secondary batteries have superior characteristics such as higher energy density than other secondary batteries, operation at high voltage, and relatively easy miniaturization. (HV), plug-in hybrid vehicles (PHVs), electric vehicles (EVs), smart phones, tablet computers, notebook computers, digital cameras, etc. are used in various applications.

  By the way, the lithium ion secondary battery generates heat due to the battery reaction at the time of charge and discharge and the internal resistance of the battery, and the deterioration progresses by the side reaction between the electrode materials at high temperature, so it is necessary to suppress the temperature rise.

  As a cooling device for cooling a lithium ion secondary battery, for example, a cooling device described in Patent Document 1 has been proposed. The cooling device described in Patent Document 1 includes a metal cooling member having a flat heat transfer surface on the outer surface of the top wall and having a coolant passage through which the coolant flows, and the lithium ion secondary battery is cooled It is placed on a heat transfer surface of a member via a heat conduction sheet made of synthetic resin such as silicon resin, and from the refrigerant flowing through the refrigerant passage of the cooling member, lithium ion is introduced via the top wall of the cooling member and the heat conduction sheet. The lithium ion secondary battery is cooled by cold heat transmitted to the secondary battery.

  The battery case of a lithium ion secondary battery cooled by the cooling device as described above is required to have excellent heat conductivity, and Patent Document 1 discloses aluminum as a battery case of a lithium ion secondary battery. Using a metal such as stainless steel is described.

  However, recently, in order to cool a lithium ion secondary battery efficiently, it is required to further improve the thermal conductivity of the battery case.

Patent No. 6020942

  The object of the present invention is made in view of the above situation, and provides a method of manufacturing a battery case main body used for a square battery case whose thermal conductivity is improved as compared with the battery case described in Patent Document 1. With the goal.

  The present invention comprises the following aspects in order to achieve the above object.

1) A method of manufacturing a battery case main body which has a rectangular tube shape with one end opened and the other end closed and used for a rectangular battery case,
By applying a coating liquid containing carbon particles and a binder to a portion of the entire surface to be coated of the aluminum foil and drying, a carbon particle layer is partially formed on the surface to be coated of the aluminum foil. Obtaining a coated foil formed in the
A plurality of the coated foils are laminated to obtain a laminate and the laminate is heated to join and integrate the plurality of coated foils, and a part of the composite material is a composite of aluminum and carbon particles Obtaining a blank of which the remainder is aluminum, and
And manufacturing the battery case body including the steps of: forming the blank into a rectangular cylindrical shape having one end opened and the other end closed by subjecting the blank to plastic deformation and then finishing.

  2) A battery case main body to be manufactured includes a side wall consisting of four side wall portions and a bottom wall integrally provided at one end of the side wall, and a partially cylindrical first side wall portion and the bottom wall of the side walls are rounded. (1) Adjacent ones of the side walls are connected, and adjacent side walls of the side walls are connected together via the second part of the partial cylindrical shape having roundness, and two adjacent side walls of the side walls and the bottom wall are partially spherical A portion connected to the third connecting portion and forming the second connecting portion and the third connecting portion of the blank is made of aluminum, and of the side wall, the bottom wall and the entire first connecting portion of the side wall The method for manufacturing a battery case main body according to the above 1), wherein a part forming at least a part is made of the composite material.

  3) In the blank, in addition to the second connecting portion and the third connecting portion, a pair of opposing side wall portions of side walls and two first connecting portions between the both side wall portions and the bottom wall The method of manufacturing the battery case body according to 2), wherein the portion to be formed is made of aluminum, and the remaining two side wall portions of the side wall, the bottom wall and the portion forming the remaining two first connecting portions are made of the composite material.

  4) In the blank, only the portion forming the second connecting portion and the third connecting portion is made of aluminum, and the portion forming the entire side wall portion, bottom wall and all first connecting portion of the side wall is made of the composite material The manufacturing method of the battery case main body according to the above 2).

  5) In the blank, in addition to the second connecting portion and the third connecting portion, all the side walls of the side walls and the portion forming all the first connecting portions are made of aluminum, and only the portion forming the bottom wall is The manufacturing method of the battery case main body of said 2) description which consists of a composite material.

  6) The blank is rectangular, and the blank is subjected to press processing including drawing processing and ironing processing or impact processing, and then subjected to finishing processing for trimming formed ears. The manufacturing method of the battery case main body in any one of).

  7) The blank is oval, and the blank is subjected to press processing including drawing processing and pressing processing including impact processing or impact processing, and then subjected to finishing processing for trimming formed ears. The manufacturing method of the battery case main body in any one of 5).

  8) The method for producing a battery case body according to any one of the above 1) to 7), wherein the carbon particles are at least one selected from the group consisting of carbon nanotubes, graphene, graphite particles and carbon fibers.

  9) The method for producing a battery case body according to any one of the above 1) to 8), wherein the composite material comprises an aluminum matrix and carbon particles dispersed in the aluminum matrix.

  10) A plurality of carbon particle dispersed layers in which the carbon particles are dispersed in a surface direction in an aluminum material constituting the aluminum matrix, and a plurality of aluminum layers formed of the aluminum material constituting the aluminum matrix The method according to the above 9), wherein the carbon particle dispersion layer and the aluminum layer are alternately arranged in a stack in the thickness direction of the composite material.

  According to the battery case using the battery case main body manufactured by the method of the above 1) to 10), at least a part of the whole of the side wall and the bottom wall of the case main body is complexed with aluminum and carbon particles As a result, the thermal conductivity of the portion made of the composite material is improved compared to that made of aluminum alone. Therefore, by keeping the portion facing the battery case body outer surface side of the portion made of the composite material in thermal contact with the heat transferer, the cold or heat from the heat transferer is transmitted through the composite material to the battery case It becomes possible to transmit efficiently to the power generation element stored inside. As a result, when the power generation element of the battery is cooled, the power generation element can be cooled efficiently. On the contrary, when it is necessary to heat the power generation element of the battery to the appropriate temperature, the power generation element can be efficiently heated to the appropriate temperature.

  Moreover, a blank consisting of a composite material in which a part of aluminum and carbon particles are complexed and the balance consisting of aluminum, a coating liquid containing carbon particles and a binder, After obtaining a coated foil in which a carbon particle layer is partially formed on the surface to be coated of the aluminum foil by coating and drying on a part of the inner foil, a plurality of the coated foils are laminated. Since the laminate can be produced by joining and integrating the plurality of coating foils by heating the laminate and removing the binder, the laminate can be manufactured relatively inexpensively. Furthermore, by forming a portion having a high degree of plastic deformation in the post-pressing process of the blank with aluminum having high formability, it has the composite material which is excellent in thermal conductivity but small in elongation. The battery case body can be easily manufactured at low cost.

  The battery case main body to be manufactured by the method according to the above 1) comprises a side wall comprising four side wall portions and a bottom wall integrally provided at one end of the side wall, and the side wall portions and the bottom wall of the side walls have roundness Adjacent side walls of the side walls are continuous with each other via the cylindrical first connection portion, and the adjacent side wall portions of the side walls are continuous with each other through the partially cylindrical second connection portion having a roundness. In the case of being connected via the partially spherical third connecting portion, the portion forming the second connecting portion and the third connecting portion in the blank has a high degree of plastic deformation at the time of press working, Even in this case, according to the method of the above 2), since the portion to be the second connecting portion and the portion forming the third connecting portion in the blank are made of aluminum, press processing can be easily performed at low cost. Can.

  According to the battery case provided with the battery case main body manufactured by the method of the above 3), the temperature control of the battery can be efficiently performed. That is, the battery is generally mounted on a heat transferer, but in this case, at least a part of the bottom wall in contact with the heat transferer and the opposing one near the center of the battery 1 When the pair of side wall portions is formed of a composite material, heat transfer between the battery and the heat transferer is performed via the bottom wall and both side wall portions, and the heat transfer path is increased. The temperature control of the battery can be performed efficiently.

  According to the battery case provided with the battery case main body manufactured by the method of the above 4), the heat is transmitted from the heat transferer through all the side wall portions and the bottom wall of the side wall of the battery case main body. It is possible to efficiently perform the heat transfer of cold heat to the central portion of the battery that is likely to be a high temperature and the heat transfer to the central portion of the battery where heat is not easily transmitted.

  According to the battery case provided with the battery case body manufactured by the method of 5), the temperature control of the battery can be efficiently performed. That is, the battery is generally mounted on a heat transferer, but in this case, if only the bottom wall in contact with the heat transferer is formed of a composite material, the heat transferor and the battery Heat transfer between the layers is not hindered, and the temperature control of the battery can be performed efficiently. In addition, the material cost is reduced because only the necessary minimum portion is formed of the composite material.

  According to the method of the above 7), since the amount of ears formed when the blank is subjected to press processing including drawing processing and ironing processing or impact processing is reduced, finishing processing for trimming the ears is performed Can be done relatively easily.

  According to the method of the above 8), the thermal conductivity of the used composite can be improved, and as a result, the thermal conductivity of the composite can be surely improved. In addition, the composite of aluminum and carbon particles in the composite can be reliably performed.

  According to the method of the above 9), the deviation of carbon particles in the aluminum matrix of the composite used is reduced, and the thermal conductivity of the composite can be made uniform.

  According to the method of the above 10), since the carbon particle dispersed layer of the composite material to be used and the aluminum layer are alternately arranged in the form of a laminate in the thickness direction of the composite material, the thickness of the carbon particle dispersed layer It is possible to increase the number of carbon particle dispersion layers while making the thickness of the composite as thin as possible, and the thermal conductivity of the composite material can be effectively increased.

It is a perspective view which shows the prismatic lithium ion secondary battery in which the battery case which has a battery case main body manufactured by the method of this invention was used. It is a partially cutaway perspective view which shows the battery case main body of the battery case of the square lithium ion secondary battery of FIG. FIG. 3 is an enlarged cross-sectional view showing a composite forming at least a part of a side wall of the battery case body of FIG. It is a top view of the blank used for manufacturing the battery case main body shown in FIG. It is a perspective view which shows the semi-finished product of the battery case main body obtained by giving press work to the blank shown in FIG. It is a perspective view which shows the method to finish-process to the semi-finished product shown in FIG. It is the schematic explaining the process of obtaining the coating foil in the method of producing the blank shown in FIG. It is a schematic sectional drawing of the strip material of coating foil. It is the schematic which shows the method of cut | disconnecting the strip material of coating foil. It is a schematic side view of a layered product. It is the schematic in the case of joining and integrating several coating foil by a pressure heating sintering apparatus. It is a top view which shows the modification of the blank used for manufacturing the battery case main body shown in FIG. It is a partially cutaway perspective view which shows the 1st modification of the battery case main body of the battery case of the square lithium ion secondary battery of FIG. It is a top view of the blank used for manufacturing the battery case main body shown in FIG. It is a top view which shows the modification of the blank used for manufacturing the battery case main body shown in FIG. It is a partially cutaway perspective view which shows the 2nd modification of the battery case main body of the battery case of the square lithium ion secondary battery of FIG. FIG. 17 is a plan view of a blank used to manufacture the battery case main body shown in FIG. 16. It is a top view which shows the modification of the blank used for manufacturing the battery case main body shown in FIG. It is a partially cutaway perspective view which shows the 3rd modification of the battery case main body of the battery case of the square lithium ion secondary battery of FIG. FIG. 20 is a plan view of a blank used to manufacture the battery case main body shown in FIG. 19; It is a top view which shows the modification of the blank used for manufacturing the battery case main body shown in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. This embodiment uses the battery case according to the present invention for a lithium ion secondary battery.

  In the following description, the same components and the same parts are denoted by the same reference symbols throughout the drawings.

  FIG. 1 shows a prismatic lithium ion secondary battery having a battery case using a battery case main body manufactured by the method of the present invention, and FIG. 2 shows a battery case main body manufactured by the method of the present invention, These show the detailed structure of the composite material which forms at least one part of a battery case main body. Moreover, FIGS. 4-11 shows the manufacturing method of a battery case main body.

  In FIG. 1, the prismatic lithium ion secondary battery 100 comprises a prismatic battery case 101 and a power generation element (not shown) housed in the battery case 101, and a pair of terminals 102 is provided on the upper end face in a projecting manner. It is done.

  The battery case 101 is joined to the rectangular cylindrical battery case main body 103 with the upper end opened and the lower end closed, and the upper end portion of the battery case main body 103 by laser welding or the like to close the upper end opening of the battery case main body 103 And an aluminum closing member 104.

  As shown in FIG. 2, the battery case main body 103 of the battery case 101 is integrally provided on a rectangular cylindrical side wall 105 with open upper and lower ends and the lower end (one end) of the side wall 105 to close the lower end opening of the side wall 105 And the bottom wall 106.

  The side walls 105 of the battery case main body 103 face each other with a first side wall portion pair 107 composed of two side wall portions 107 a which are opposed to each other and the lengths of both upper and lower sides are longer than the vertical height of the side wall 105. And a second side wall pair 108 consisting of two other side wall portions 108 a whose lengths on the upper and lower sides are shorter than the height in the vertical direction of the side wall 105. , 108 of the side walls 107a, 108a and the bottom wall 106 are connected via the rounded first cylindrical connecting portion 109, and two adjacent side walls 107a, 108a of the side wall 105 are rounded. The two adjacent side walls 107a and 108a of the side wall 105 and the bottom wall 106 are connected via the third connection 111. There.

  As shaded in FIG. 2, the two side wall portions 107 a of the first side wall portion pair 107 of the side wall 105, the first connecting portion 109 between the both side wall portions 107 a and the bottom wall 106, and the bottom The wall 106 is formed of a composite 60 formed by combining aluminum and carbon particles, and the two side walls 108 a of the second side wall pair 108 of the side wall 105, the both side walls 108 a and the bottom wall A first connecting portion 109, an entire second connecting portion 110 and an all third connecting portion 111 between them are formed of aluminum.

  In the lithium ion secondary battery 100 including the battery case main body 103 shown in FIG. 2, at least one of the side wall 107 a, the other side wall 107 a, and the bottom wall 106 of the first side wall pair 107. One is a heat transfer portion for transferring heat to the power generation element of the lithium ion secondary battery 100.

  As shown in FIG. 3, the composite material 60 includes an aluminum matrix 63 and carbon particles 1 dispersed in the aluminum matrix 63, and the carbon particles 1 in the surface direction of the aluminum material constituting the aluminum matrix 63. A plurality of dispersed carbon particle dispersion layers 61, a plurality of aluminum layers 62 formed of an aluminum material constituting the aluminum matrix 63, and end aluminum layers 64 at the upper and lower ends are provided in a laminated manner.

  The carbon particle dispersion layer 61 and the aluminum layer 62 are arranged in an alternately stacked state over the entire thickness direction of the composite material 60. In each carbon particle dispersed layer 61, the carbon particles 1 are dispersed in the aluminum matrix 63 in the plane direction of the composite material 60, and are hardly dispersed in the thickness direction of the composite material 60. In each aluminum layer 62, carbon particles 1 are substantially absent. Then, the plurality of carbon particle dispersion layers 61 and the plurality of aluminum layers 62 are joined and integrated by, for example, sintering and combining. The thickness of the carbon particle dispersion layer 61 is preferably, but not limited to, 1 to 100 μm. The thickness of the aluminum layer 62 is not limited, but is preferably 5 to 200 μm. One of the upper and lower end aluminum layers 64 of the composite material 60 is made of, for example, an aluminum plate 65 joined and integrated by sintering. The lower end end aluminum layer 64 is not necessarily required.

  The type of carbon particles used for the composite material 60 is not limited, but it is desirable to use one having as high thermal conductivity as possible, that is, one having high thermal conductivity. In particular, as the carbon particles, natural graphite particles and artificial graphite particles are preferably used. As natural graphite particles, scaly graphite particles and the like are used. As artificial graphite particles, isotropic graphite particles, anisotropic graphite particles, pyrolytic graphite particles and the like are used. When the carbon particles are natural graphite particles and artificial graphite particles, natural graphite particles and artificial graphite particles having an average particle diameter of 10 μm or more and 3 mm or less are suitably used.

Further, as the carbon particles of the composite material 60, at least one selected from the group consisting of carbon fibers, carbon nanotubes, and graphene may be used. As carbon fibers, pitch-based carbon fibers, PAN-based carbon fibers and the like are used.
As the carbon nanotubes, single-walled carbon nanotubes, multi-walled carbon nanotubes, vapor grown carbon fibers (VGCF (registered trademark)) and the like are used. When the carbon particles are carbon fibers, short carbon fibers having an average fiber length of 10 μm or more and 2 mm or less are particularly preferably used. When the carbon particles are carbon nanotubes, carbon nanotubes having an average length of 1 μm to 10 μm are particularly preferably used.

  The method of manufacturing the battery case main body 103 will be described with reference to FIGS.

  The battery case main body 103 forms a rectangular cylindrical semi-finished product 81 having the ears 82 as shown in FIG. 5 by subjecting the blank 80 as shown in FIG. 4 to pressing including drawing and ironing. Thereafter, as shown in FIG. 6, the semifinished product 81 is finished by finishing including trimming, and cut out by cutting a fixed length portion having the ear 82.

  The blank 80 is rectangular and forms two side walls 107a of the first side wall 107 of the side wall 105, a first connecting portion 109 between the both side walls 107a and the bottom wall 106, and a bottom wall 106. First portion 83 (hatched portion) is made of the composite material 60, and the two side wall portions 108a of the second side wall portion pair 108 of the side wall 105, between the both side wall portions 108a and the bottom wall 106 The second portion 84 forming the one connecting portion 109, the entire second connecting portion 110, and the all third connecting portion 111 is made of aluminum.

  In the method of manufacturing the blank 80, as shown in FIG. 7, the step A of obtaining the coated foil 12 in which the carbon particle layer 11 is partially formed on the coating planned surface 10a of the aluminum foil 10, and a plurality of coated foils The process B of forming the laminated body 15 of the state by which 12 was laminated | stacked, and the process C which joins and integrates the several coating foil 12 by heating the laminated body 15 are included.

  In the step A of obtaining the coating foil 12, the coating foil 12 is obtained by applying and drying a predetermined coating solution 5 on a part of the entire coating planned surface 10 a of the aluminum foil 10.

  The aluminum foil 10 forms the aluminum matrix 63 of the composite 60. The aluminum foil 10 has high thermal conductivity, and can increase the thermal conductivity of the resulting composite material 60.

  The thickness of the aluminum foil 10 is not limited, and is preferably 5 to 500 μm, and particularly preferably 10 to 50 μm.

  In FIG. 7, a strip material 10 </ b> A of the aluminum foil 10 (that is, a strip-shaped long aluminum foil 10) is used as the aluminum foil 10. The planned application surface 10a of the strip 10A of the aluminum foil 10 to which the coating liquid 5 is partially applied is one of the surfaces on both sides in the thickness direction of the strip 10A of the aluminum foil 10.

  The coating liquid 5 contains the carbon particles 1, the binder 2 and the solvent 3 for the binder 2 in a mixed state, and can be obtained, for example, as follows.

  That is, as shown in FIG. 7, the coating liquid 5 is obtained by putting the carbon particles 1, the binder 2 and the solvent 3 in the mixing container 41 and stirring and mixing them with the stirring and mixing device 42. In addition, a dispersing agent (not shown), a surface control agent (not shown), etc. are added to the coating liquid 5 as needed.

  As the carbon particles 1, for example, scale-like graphite particles such as scale-like graphite powder can be used.

  Assuming that the average particle diameter of the carbon particles 1 is “d”, d is preferably 100 μm or more. The reason is that, because d is 100 μm or more, the interface thermal resistance between the carbon particles 1 and the aluminum matrix 63 can be reliably reduced in the interior of the composite material 60, whereby the thermal conductivity of the composite material 60 This is because it is possible to increase the The upper limit of d is not limited but is preferably 1000 μm. The reason is that the crack of the carbon particle 1 at the time of application of the coating liquid 5 can be reliably suppressed.

  The average aspect ratio of the carbon particles 1 is not limited. However, since the thermal conductivity of the carbon particles 1 is generally higher as the aspect ratio of the carbon particles 1 is larger, the average aspect ratio of the carbon particles 1 is preferably as large as possible, and particularly preferably 30 or more. A desirable upper limit of the average aspect ratio is not limited but is preferably 100. The reason is that the crack of the carbon particle 1 at the time of application of the coating liquid 5 can be reliably suppressed.

  Here, the particle diameter of the carbon particles 1 means the equivalent circle diameter in the surface direction of the carbon particles 1 observed by an observation means such as an electron microscope. The average particle diameter d of the carbon particles 1 is calculated by an arithmetic average of the particle diameters of 100 carbon particles 1 arbitrarily selected from a large number of carbon particles 1. Moreover, the thickness of the carbon particle 1 is observed and measured by observation means, such as an electron microscope. The average thickness of the carbon particles 1 is calculated by an arithmetic mean of the thickness of 100 carbon particles 1 arbitrarily selected from a large number of carbon particles 1. The average aspect ratio of the carbon particles 1 is calculated by the “average particle diameter / average thickness” of the carbon particles 1.

  The binder 2 is for giving adhesion to the coating planned surface 10a of the strip material 10A of the aluminum foil 10 to the carbon particles 1, and suppressing that the carbon particles 1 fall off from the coating planned surface 10a. . The binder 2 is usually made of a resin such as an organic resin. Specifically, polyethylene oxide, polyvinyl alcohol, acrylic resin or the like can be used as the binder 2.

  The solvent 3 dissolves the binder 2. Specifically, as the solvent 3, a hydrophilic solvent (example: isopropyl alcohol, water), an organic solvent or the like can be used.

  As the stirring mixer 42, a disper, a planetary mixer, a bead mill or the like can be used.

  The coating method for coating the coating liquid 5 on the coating planned surface 10a of the strip 10A of the aluminum foil 10 is not limited. Preferably, as shown in FIG. 7, the coating liquid 5 is coated with an unwinding roll 31 for unwinding the strip 10A of the aluminum foil 10 and a winding roll 32 for unwinding the strip 10A of the aluminum foil 10. It is performed by the used roll-to-roll method.

  Furthermore, in the same figure, between the unwinding roll 31 and the winding roll 32, the three-roll type offset printing device 20 and the drying furnace 35 as the drying device are in the feed direction F of the strip 10A of the aluminum foil 10. It is installed side by side.

  The offset printing apparatus 20 applies the coating liquid 5 to the coating planned surface 10a of the strip 10A of the aluminum foil 10, and comprises an ink roll 21, a transfer roll 22 and a backup roll 23 as three rolls. And a coating liquid pan 25 as an ink pan.

  The ink roll 21 is disposed in a state in which a part of the circumferential surface 21 a in the circumferential direction is immersed in the coating liquid 5 in the coating liquid pan 25. The circumferential surface 22a of the transfer roll 22 is formed smooth. The rotation direction of the transfer roll 22 is set to the same direction as the feeding direction F of the strip 10A of the aluminum foil 10. The backup roll 23 is disposed to face the transfer roll 22.

  In the offset printing apparatus 20, the coating liquid 5 in the pan 25 is supplied and attached from the circumferential surface 21 a of the ink roll 21 to the circumferential surface 22 a of the transfer roll 22 by the rotation of the ink roll 21 and then aluminum is rotated by the rotation of the transfer roll 22. Transfer coating is performed on the planned coating surface 10 a of the strip 10 A of the foil 10.

  The drying furnace 35 is disposed downstream of the offset printing apparatus 20 in the feed direction F of the strip 10A of the aluminum foil 10 in the feeding direction F, and is applied to the coating planned surface 10a of the strip 10A of the aluminum foil 10 The solvent 3 in the coating liquid 5 is evaporated and removed from the coating liquid 5 by heating and drying the coating liquid 5.

  The strip 10A of the aluminum foil 10 unwound from the unwinding roll 31 is sequentially wound between the transfer roll 22 and the backup roll 23 of the offset printing apparatus 20 and the drying furnace 35 and then wound around the winding roll 32. To be taken.

  When the strip 10A of the aluminum foil 10 passes between the transfer roll 22 and the backup roll 23, the coating liquid 5 is coated by the transfer roll 22 on the planned surface 10a of the strip 10A of the aluminum foil 10 Be done.

  Before applying the coating liquid 5, the coating planned surface 10a of the strip 10A of the aluminum foil 10 is partially covered with a masking sheet (not shown) made of a resin sheet or the like, and in this state the coating liquid Apply 5 Thereby, the coating form 5 is coated on the part which is not covered with the masking sheet in the coating plan surface 10a.

  Thereafter, the coating solution 5 applied to the planned coating surface 10 a passes through the drying furnace 35 and the solvent 3 is removed by evaporation from the coating solution 5. Next, the masking sheet is removed from the planned coating surface 10a. As a result, the carbon particle layer 11 is partially formed on the planned coating surface 10 a of the strip 10 A of the aluminum foil 10, that is, the strip 12 A of the coated foil 12 is obtained. The portion where the carbon particle layer 11 is formed in the planned coating surface 10a is the portion where the coating liquid 5 is coated in the planned coating surface 10a, that is, the portion not covered by the masking sheet in the planned coating surface 10a It is.

  In the coating method of the coating liquid 5 by the three-roll type offset printing apparatus 20 as described above, when the circumferential surface 22 a of the transfer roll 22 abuts on the coating planned surface 10 a of the strip 10 A of the aluminum foil 10 The coating liquid on the circumferential surface 22a of the transfer roll 22 adheres to the planned surface 10a. Then, when the circumferential surface 22a of the transfer roll 22 separates from the planned surface 10a, the coating liquid 5 is transferred onto the planned surface 10a. At that time, as shown in FIG. 8, it is desirable that the coating liquid 5 be coated on the coating planned surface 10 a so that the carbon particles 1 in the coating liquid 5 do not overlap. The reason is described below.

  That is, when the coating liquid 5 is applied to the planned coating surface 10 a in a state where the carbon particles 1 overlap with each other, the carbon particles 1 are dried by drying the coating liquid 5 using a drying furnace (drying device) 35. A carbon particle layer in a state of overlapping is formed on the surface 10a to be coated. In the strip material of the coating foil which has such a carbon particle layer, it is very difficult to join and integrate several coating foil favorably in process C to join and integrate. Therefore, as shown in FIG. 8, the coating liquid 5 is to be coated on the intended coating surface 10 a so that the carbon particles 1 in the coating liquid 5 do not overlap, as shown in FIG. It is good to be coated on

The coating amount of the carbon particles 1 per unit area to be coated on the planned coating surface 10a is not limited. In particular, it is desirable that the coating liquid 5 be applied to the planned surface 10 a so that the coating amount of the carbon particles 1 is 1 to 80 g / m ² . The reason is as follows.

When the coating amount of the carbon particles 1 is less than 1 g / m ^{2, the} effect of increasing the thermal conductivity of the composite material 60 by the carbon particles 1 is small.

When the coating amount of the carbon particles 1 exceeds 80 g / m ² , the carbon particles 1 overlap each other by about 5 to 10 layers, and as a result, the coated foils are laminated to form the laminate 15 and the laminate 15 is heated. In step C of bonding and integrating the plurality of coating foils 12, aluminum may not enter the overlapping portion of the carbon particles, and there is a possibility that the bonding will be insufficient. The desirable upper limit of the coating amount of the carbon particles 1 that can be applied is about 80 g / m ² . If bonding of the plurality of coating foils 12 is insufficient, improvement in the thermal conductivity of the composite material 60 can not be expected, and processing with plastic deformation such as deep drawing becomes difficult.

Therefore, by coating the coating liquid 5 on the planned surface 10a so that the coating amount of the carbon particles 1 is 1 to 80 g / m ² , the plurality of coating foils 12 are joined and integrated well. The thermal conductivity of the composite 60 can be reliably increased.

  Furthermore, the coating of the coating liquid 5 is performed by the three-roll type offset printing apparatus 20 so that the coating liquid 5 can be easily and surely applied to the coating planned surface 10 a so that the carbon particles 1 do not overlap with each other. It can be coated. The reason is as follows.

  That is, in the three-roll offset printing apparatus 20, the amount of the coating liquid 5 attached from the circumferential surface 21 a of the ink roll 21 to the circumferential surface 22 a of the transfer roll 22 is the coating applied to the circumferential surface 21 a of the ink roll 21. The amount is smaller than the amount of the processing liquid 5, and can be easily adjusted by changing the pressure condition between the ink roll 21 and the transfer roll 22. From this, the coating liquid 5 is applied by appropriately adjusting the amount of the coating liquid 5 adhering to the circumferential surface 21 a of the ink roll 21 and the pressure condition between the ink roll 21 and the transfer roll 22. It can be thinly coated on the planned work surface 10a. Therefore, the coating liquid 5 can be easily and reliably applied to the planned surface 10a so that the carbon particles 1 do not overlap with each other.

  Moreover, in order to apply | coat the coating liquid 5 reliably so that carbon particle 1 comrades do not overlap, you may use a gravure printing apparatus as a coating apparatus.

  On the other hand, ink jet, knife coater, die coater, spray coater, curtain coater etc. are known as other common coating devices, but in such a coating device, carbon particle 1 as a filler is too large Therefore, it is difficult to thinly coat the coating liquid 5 on the planned coating surface 10a, and as a result, the coating liquid 5 is easily coated so that the carbon particles 1 overlap with each other. Therefore, in order to apply the coating liquid 5 so that the carbon particles 1 do not overlap with each other, it is desirable to use the above-described three-roll offset printing device 20 or a gravure printing device as the coating device.

  As shown in FIG. 9, in step B of forming the laminate 15, the strip material 12A of the coated foil 12 unwound from the winding roll 32 is cut into a predetermined shape by a cutting machine 39. As a result, a plurality of coating foils 12 of a predetermined shape (e.g. substantially square shape) are cut out from the strip material 12A of the coating foil 12.

  Next, as shown in FIG. 10, a plurality of coating foils 12 are laminated to form a laminate 15 in a state in which the plurality of coating foils 12 are laminated. The laminate 15 is used as a preform (sintered material). In this laminate 15, the plurality of coating foils 12 constituting the laminate 15 have the carbon particle layers 11 in the coating foil 12 formed such that the portions of the coating foil 12 on which the carbon particle layers 11 are formed overlap. It is laminated so that the part which is not done may overlap.

  The number of laminated layers of the coating foil 12 for forming the laminated body 15 is not limited, and is set according to the desired thickness of the composite material 60, and is, for example, 10 to 1000.

  In step C of joining and integrating the coated foils 12 of the laminate 15, the laminate 15 is sintered by heating in a predetermined sintering atmosphere (eg, non-oxidizing atmosphere) using a pressure heating and sintering apparatus or the like. As a result, a plurality of coating foils 12 are collectively joined and integrated (sintered and integrated).

  The sintering method of the laminate 15 is selected from vacuum hot pressing, spark plasma sintering (SPS), hot isostatic sintering (HIP), rolling and the like. The discharge plasma sintering method is also called a pulse current sintering method.

  Specifically, as shown in FIG. 11, for example, the laminate 15 and the aluminum plate 65 (in the sintering chamber 51 of a pressure heating and sintering apparatus (eg: vacuum hot press apparatus, discharge plasma sintering apparatus) 50) 3) and pressing the laminate 15 in the direction of lamination of the coated foil 12 (that is, in the thickness direction of the laminate 15) in a predetermined sintering atmosphere by the sintering apparatus 50, while performing predetermined baking The laminate 15 is sintered by heating under the sintering conditions, whereby the plurality of coating foils 12 are collectively joined and integrated (sintered and integrated), and the aluminum plate 65 is integrally joined (sintered and integrated) ). As a result, the composite material 60 of the aspect shown in FIG. 3 is obtained.

  Pressurization to the laminated body 15 is performed, for example, by sandwiching the laminated body 15 in the thickness direction with a pair of punches 52 and 52 provided in the sintering device 50 and pressing the laminated body 15.

  The heating temperature of the laminate 15 to sinter the laminate 15, ie, the sintering temperature of the laminate 15 is not limited, and is usually not higher than the melting point of the aluminum material forming the aluminum foil 10, in particular It is desirable to set the temperature between the melting point of the aluminum material and the temperature about 50 ° C. lower than the melting point. The reason is that the laminate 15 can be surely sintered (that is, the plurality of coating foils 12 can be surely joined and integrated). Specifically, when the aluminum foil 10 is, for example, an aluminum foil, the sintering temperature of the laminate 15 is desirably set to 550 to 620 ° C.

  Here, the sintering temperature of the laminate 15 means a temperature at which the plurality of coating foils 12 are joined and integrated (that is, a temperature at which the plurality of coating foils 12 are sintered and integrated).

  The binder 2 present in the laminate 15 is removed from the laminate 15 by heating the laminate 15 in this step C. Specifically, the binder 2 present in the laminate 15 is sublimated or reduced during heating of the laminate 15 so that the temperature of the laminate 15 rises from approximately room temperature to the sintering temperature of the laminate 15 in this step C. It disappears by decomposition etc. and is removed from layered product 15.

  By heating the laminated body 15 as described above, in the portion of the coated foil 12 where the carbon particle layer 11 is formed, a part of the aluminum material of the aluminum foil 10 penetrates into the carbon particle layer 11 to carbon The fine voids existing in the particle layer 11 (eg, the gaps between the carbon particles 1 in the carbon particle layer 11) are filled, and the voids substantially disappear. As a result, the density of the composite material 60 is increased and the strength of the composite material 60 is improved.

  In addition, carbon particles 1 in the carbon particle layer 11 are a composite in a portion where the carbon particle layer 11 is formed in the coating foil 12 by a part of the aluminum material of the aluminum foil 10 penetrating into the carbon particle layer 11. The carbon particle layer 11 is dispersed in the aluminum matrix 63 of the material 60 in the surface direction of the composite material 60, and the carbon particle layer 11 becomes the carbon particle dispersion layer 61 of the composite material 60 shown in FIG. Also, the aluminum foil 10 becomes the aluminum layer 62 of the composite material 60.

  Therefore, in the composite material 60, the carbon particle dispersion layer 61 and the aluminum layer 62 are arranged in a state of being alternately stacked over the entire thickness direction of the composite material 30 as described above.

  Moreover, by heating the laminated body 15 as mentioned above, in the part in which the carbon particle layer 11 in the coating foil 12 is not formed, the part of the aluminum foil 10 which mutually overlaps in a thickness direction joins and integrates. It is sintered and integrated).

  In this way, a blank 80 which is partially composed of the composite material 60 and the remainder is composed of aluminum is obtained.

  Thereafter, as described above, the blank 80 is subjected to press processing including drawing processing and ironing processing to form a rectangular cylindrical semi-finished product 81 having the ears 82 as shown in FIG. 5 and thereafter, as shown in FIG. As shown, the battery case body 103 is manufactured by applying finishing including trimming to the semi-finished product 81 and cutting out the opening-side fixed length portion having the ear 82.

  FIG. 12 shows a modification of the blank used to manufacture the battery case main body 103 shown in FIG.

  The blank 80A shown in FIG. 12 is formed into an elliptical shape by cutting a part of the first portion 83 and the second portion 84 of the blank 80 shown in FIG. In this case, it is possible to reduce the height of the ears in the rectangular tubular semi-finished product 81 having the ears 82 formed by subjecting the blank 80 to pressing processing including drawing processing and ironing processing.

  FIG. 13 shows a first modification of the battery case main body manufactured by the method of the present invention.

  The battery case body 120 shown in FIG. 13 has two side walls 108a of the second side wall pair 108 of the side wall 105, the both side walls 108a, and the bottom wall 106, as shaded in FIG. Between the first connecting portion 109 and the bottom wall 106 are formed of a composite material 60 formed by combining aluminum and carbon particles, and the two side wall portions of the first side wall portion 107 of the side wall 105 are formed. 107a, a first connecting portion 109 between the both side walls 107a and the bottom wall 106, an entire second connecting portion 110 and an all third connecting portion 111 are formed of aluminum.

  FIG. 14 shows a blank used to manufacture the battery case main body 120 shown in FIG.

  In FIG. 14, the blank 85 has a square shape, and both side wall portions 108 a of the second side wall portion pair 108 of the side wall 105, the first connecting portion 109 between the both side wall portions 108 a and the bottom wall 106, and the bottom wall The first portion 86 (hatched portion) forming the portion 106 is made of the composite material 60, and the two side wall portions 107a of the first side wall portion pair 107 of the side wall 105, the both side wall portions 107a and the bottom wall 106 The first connecting portion 109, the second connecting portion 110, and the second portion 87 forming the third connecting portion 111 are made of aluminum.

  The method of manufacturing the blank 85 is the same as the method of manufacturing the blank 80 shown in FIG. 4, and the coating liquid in the step of obtaining the coated foil 12 in which the carbon particle layer 11 is formed on the coating planned surface 10 a of the aluminum foil 10 Only the coated part of 5 is different.

  FIG. 15 shows a modification of the blank used to manufacture the battery case main body 120 shown in FIG.

  The blank 85A shown in FIG. 15 is formed into an elliptical shape by cutting a part of the first portion 86 and the second portion 87 of the blank 85 shown in FIG. In this case, it is possible to reduce the height of the ear in the rectangular tubular semifinished product having the ear formed by subjecting the blank 85 to press processing including drawing processing and ironing processing.

  FIG. 16 shows a second modification of the battery case main body manufactured by the method of the present invention.

  The battery case main body 121 shown in FIG. 16 has the side wall portions 107a and 108a of all the side wall portions 107 and 108, all the side wall portions 107a and 108a and the bottom, as shaded in FIG. A first connecting portion 109 between the wall 106 and the bottom wall 106 is formed of a composite material 60 formed by combining aluminum and carbon particles, and all the second connecting portions 110 and all the third portions are formed. The connecting portion 111 is formed of aluminum.

  FIG. 17 shows a blank used to manufacture the battery case main body 121 shown in FIG.

  In FIG. 17, the blank 90 has a square shape, and each side wall 107a, 108a of the side wall pair 107, 108 of the side wall 105, a first connecting portion between all the side walls 107a, 108a and the bottom wall 106. 109, and the first portion 91 (hatched portion) forming the bottom wall 106 is made of the composite material 60, and the second portion 92 forming all the second connecting portions 110 and all the third connecting portions 111 is aluminum. It consists of

  The method of manufacturing the blank 90 is the same as the method of manufacturing the blank 80 shown in FIG. 4, and the coating liquid in the step of obtaining the coated foil 12 in which the carbon particle layer 11 is formed on the coating planned surface 10 a of the aluminum foil 10 Only the coated part of 5 is different.

  FIG. 18 shows a modification of the blank used to manufacture the battery case main body 121 shown in FIG.

  The blank 90A shown in FIG. 18 is formed into an elliptical shape by cutting a part of the first portion 91 and the second portion 92 of the blank 90 shown in FIG. In this case, it is possible to reduce the height of the ear in the rectangular tubular semifinished product having the ear formed by subjecting the blank 90A to press processing including drawing processing and ironing processing.

  FIG. 19 shows a third modification of the battery case main body manufactured by the method of the present invention.

  In the battery case main body 122 shown in FIG. 19, the bottom wall 106 is formed of a composite material 60 formed by combining aluminum and carbon particles, as shaded in FIG. Each side wall 107a, 108a of the pair of side walls 107, 108 of the side wall 105 and all the first to third connecting portions 109, 11, 111 are formed of aluminum.

  FIG. 20 shows a blank used to manufacture the battery case body 122 shown in FIG.

  In FIG. 20, the blank 95 has a rectangular shape, and the first portion 96 (hatched portion) forming the bottom wall 106 is made of the composite material 60, and all the side wall portions 107a and 108a of the side wall 105 The second portion 97 forming the one connecting portion 109, the entire second connecting portion 110, and the all third connecting portion 111 is made of aluminum.

  The method of manufacturing the blank 95 is the same as the method of manufacturing the blank 80 shown in FIG. 4, and the coating liquid in the step of obtaining the coated foil 12 in which the carbon particle layer 11 is formed on the coating planned surface 10 a of the aluminum foil 10 Only the coated part of 5 is different.

  FIG. 21 shows a modification of the blank used to manufacture the battery case main body 122 shown in FIG.

  The blank 95A shown in FIG. 21 is formed into an elliptical shape by cutting off a part of the second portion 97 of the blank 80 shown in FIG. In this case, it is possible to reduce the height of the ear in the rectangular tubular semi-finished product 81 having the ear formed by subjecting the blank 95A to press processing including drawing processing and ironing processing.

  The method according to the present invention is suitably used, for example, for producing a battery case main body in a battery case of a prismatic lithium ion secondary battery.

1: Carbon particle 2: Binder 5: Coating liquid 10: Aluminum foil 10a: Coating planned surface 11: Carbon particle layer 12: Coating foil 15: Laminated body 60: Composite material 80, 80A, 85, 85A, 90, 90A, 95, 95A: Blanks 103, 120, 12, 122: Battery case body 105: Side wall 106: Bottom wall 107a, 108a: Side wall portion 109: first connecting portion 110: second connecting portion 111: third connecting portion

Claims (10)

A method of manufacturing a battery case main body which has an open-ended one end and a closed other end, and is used for a rectangular battery case,
By applying a coating liquid containing carbon particles and a binder to a portion of the entire surface to be coated of the aluminum foil and drying, a carbon particle layer is partially formed on the surface to be coated of the aluminum foil. Obtaining a coated foil formed in the
A plurality of the coated foils are laminated to obtain a laminate and the laminate is heated to join and integrate the plurality of coated foils, and a part of the composite material is a composite of aluminum and carbon particles Obtaining a blank of which the remainder is aluminum, and
And manufacturing the battery case body including the steps of: forming the blank into a rectangular cylindrical shape having one end opened and the other end closed by subjecting the blank to plastic deformation and then finishing. A battery case main body to be manufactured includes a side wall comprising four side wall portions and a bottom wall integrally provided at one end of the side wall, and a partial cylindrical first connection having rounded side walls and bottom wall of the side wall The adjacent side wall portions of the side walls are connected via the second portion, and the adjacent side wall portions and the bottom wall of the side wall are further formed of a partially spherical third shape. A portion connected to the connecting portion and forming a second connecting portion and a third connecting portion of the blank is made of aluminum, and at least one of all side wall portions, a bottom wall and an entire first connecting portion of the side wall The method for manufacturing a battery case body according to claim 1, wherein a portion forming the portion is made of the composite material. In the blank, in addition to the second connecting portion and the third connecting portion, a pair of opposing side walls of side walls and two first connecting portions between the both side walls and the bottom wall are formed. The method for manufacturing a battery case body according to claim 2, wherein the portion is made of aluminum, and the remaining two side wall portions of the side wall, the bottom wall and the portion forming the remaining two first connecting portions are made of the composite material. In the blank, only the portion forming the second connecting portion and the third connecting portion is made of aluminum, and the portion forming the entire side wall portion, bottom wall and all first connecting portion of the side wall is made of the composite material. The manufacturing method of the battery case main body of Claim 2. In the blank, in addition to the second connecting portion and the third connecting portion, all the side walls of the side wall and the portion forming all the first connecting portions are made of aluminum, and only the portion forming the bottom wall is the composite The manufacturing method of the battery case main body of Claim 2 which consists of. The blank according to any one of claims 1 to 5, wherein the blank is rectangular, and the blank is subjected to press processing including drawing processing and ironing processing or impact processing, and then trimming formed ears. The manufacturing method of the battery case main body in any one of. The blank according to any one of claims 1 to 5, wherein said blank is oval, and said blank is subjected to press processing including drawing processing and ironing processing or impact processing, and then trimming formed ears. The manufacturing method of the battery case main body in any one of the above. The method for producing a battery case body according to any one of claims 1 to 7, wherein the carbon particles are at least one selected from the group consisting of carbon nanotubes, graphene, graphite particles and carbon fibers. The method according to any one of claims 1 to 8, wherein the composite material comprises an aluminum matrix and carbon particles dispersed in the aluminum matrix. The composite material includes a plurality of carbon particle dispersed layers in which the carbon particles are dispersed in a plane direction in an aluminum material constituting the aluminum matrix, and a plurality of aluminum layers formed of the aluminum material constituting the aluminum matrix The method of manufacturing a battery case body according to claim 9, wherein the carbon particle dispersed layer and the aluminum layer are alternately arranged in a laminated shape in a thickness direction of the composite material.

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