JP4771765B2 - Battery case - Google Patents

Description

  The present invention relates to a battery case, and more particularly to an improved structure of a battery case that has a bottomed cylindrical shape capable of accommodating a power generation element and is preferably used as a constituent member of a secondary battery. .

  Conventionally, secondary batteries such as lead-acid batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and lithium ion batteries have been widely used as rechargeable power sources in various apparatuses and devices. And in recent years, among them, especially small secondary batteries are portable communication devices, information devices, acoustic devices, or electric vehicles and hybrid vehicles that use an electric motor as a main drive source or auxiliary drive source for traveling, etc. In the future, it will be used as a power supply device for devices and the like that are expected to evolve further, and its market scale is rapidly expanding.

  By the way, as is well known, in many of such secondary batteries, various power generating elements are housed in a battery case having a cylindrical shape with a bottom on one side, and the opening of the battery case has a predetermined opening. It is sealed with a lid and is provided with an electrode terminal. And in such a secondary battery, in order to obtain excellent battery performance, sufficient lightness that can improve the weight energy density and excellent ability to effectively release heat generated during power generation or discharge. It is desired to have high strength capable of suppressing heat transfer (cooling performance) and deformation due to an increase in internal pressure during power generation or discharge.

  For this reason, conventional secondary batteries generally include a battery case made of a synthetic resin that can reduce the weight of the entire battery, or a battery case made of metal such as iron or aluminum that can exhibit excellent heat conductivity and high strength. Used and configured. However, in a secondary battery configured using a battery case made of a synthetic resin, the battery case is inevitably thickened to compensate for the lack of strength, and therefore sufficient heat transfer performance is achieved. There was a drawback that it was difficult to ensure. On the other hand, even in a secondary battery using a metal battery case, it is inevitable that the weight energy density is lowered by the amount of weight, and therefore, it is particularly small and light and has high energy. The problem of being unsuitable for various power supply devices for portable devices that require density was inherent.

  Under such circumstances, a case body made of a synthetic resin having a bottomed cylindrical shape in which the power generation element can be accommodated is provided, and a metal layer is cast or metal powder on at least the outer surface of the cylinder wall portion of the case body. In recent years, a battery case (for example, see Patent Document 1 below) that is integrally formed by applying or spraying, a battery case that is formed by integrally fixing a metal plate by insert molding, and the like have been proposed. Also, some of them are used practically. In these battery cases, while maintaining the sufficient lightness of the case body made of synthetic resin, the entire battery case is excellent due to the metal layer and the metal plate integrally provided on the outer surface of the case body. Therefore, it is possible to effectively exhibit high heat conductivity and high strength, thereby greatly contributing to improvement of battery performance.

  However, in a secondary battery obtained by using such a conventional battery case having a two-layer or double structure of metal and resin, a synthetic resin material constituting the case body and a cylindrical wall portion of the case body Due to the difference in coefficient of linear expansion between the metal layer and the metal plate that are integrally provided on the outer surface of the battery, the temperature inside the battery during use and when it is not used and the change in ambient temperature The case main body and the metal layer or the metal plate are stretched and contracted by different amounts, which may cause the metal layer or the metal plate to peel from the case main body. Therefore, in the conventional battery case as described above, there is a big problem that the reliability in maintaining the excellent battery performance stably is lacking.

  In order to solve such problems, for example, a metal plate formed by bending both end portions in the length direction to one side in the plate thickness direction is used. Use a battery case that is fixed by insert molding so that both end portions bent at least with respect to the outer surface of the cylindrical wall portion are located on the opening side and the bottom wall side of the cylindrical wall portion, respectively. Is possible. That is, by bending the metal plate portions located on the opening side and the bottom wall portion side of the case body inward, respectively, and extending portions extending in the direction intersecting the height direction of the cylindrical wall portion from those bent portions, This is to prevent the extension in the height direction due to the thermal expansion of the cylindrical wall portion.

  However, in such a battery case, the extending portions provided on the respective metal plate portions located on the bottom wall side and the opening side of the case main body have inner holes (accommodating the power generation elements). The length of each extension part is inevitably limited so as not to enter the part), and therefore, particularly in the extension part provided on the metal plate part located on the opening side of the case body It has been difficult to ensure a length sufficient to sufficiently prevent the elongation in the height direction due to thermal expansion of the cylindrical wall portion.

  That is, if the extending part provided in the metal plate part located on the bottom wall part side of the case main body is formed so as to extend substantially in parallel on the outer surface or inside the bottom wall part, for example. Although it is possible to ensure a sufficient length to prevent the cylindrical wall portion from extending to the bottom wall portion due to thermal expansion without entering the inner hole of the case body, About the extension part provided in the metal plate part located, the length will be restrict | limited to the very short length of the grade which does not exceed the thickness of the thin cylindrical wall part less than 1 mm.

  Therefore, the metal plate whose portions located on the opening side and the bottom wall side of the case body are simply bent inward is fixed integrally to the outer surface of the cylindrical wall portion by insert molding. In the battery case, it is not possible to sufficiently prevent the expansion in the height direction due to the thermal expansion of the cylindrical wall, and eventually the metal layer and the metal plate are peeled off from the case body due to the difference in the amount of expansion and contraction accompanying the temperature change. There was no concern about what would happen.

Japanese Patent Laid-Open No. 2002-329483

  Here, the present invention has been made in the background as described above, and the problem to be solved is at least a cylindrical wall portion of a case body made of a synthetic resin having a cylindrical shape with a bottom on one side. In a battery case in which excellent heat transfer and high strength can be effectively exhibited while securing sufficient lightness by being integrally fixed to the outer surface of the metal plate Another object of the present invention is to provide an improved structure so that peeling of the metal plate from the case main body due to expansion and contraction of the case main body and the metal plate due to temperature change can be advantageously prevented.

  And, in the present invention, in order to solve such a problem, the gist of the present invention is a synthetic resin having a cylindrical shape with a bottom on one side and having an accommodating portion for accommodating a power generation element inside. A battery case in which a metal plate is integrally fixed by insert molding to at least an outer surface of a cylindrical wall portion of a case body made of metal, wherein the metal plate has a plurality of through holes, and the cylinder of the case body The plurality of through-holes are provided so as to be positioned side by side in a direction corresponding to the height direction of the wall portion, and the plurality of through-holes are provided at the respective peripheral edges of the plurality of through-holes on the fixing surface of the metal plate to the cylindrical wall portion Each of the plurality of through-holes and the plurality of cylinders are provided integrally with each other, each having a cylindrical shape surrounding each separately and extending in a direction intersecting the height direction of the cylinder wall. Intrude into each of the extension parts The intrusion portion that is integrally fixed to the inner peripheral surface of each through hole and the inner peripheral surface of each cylindrical extension portion is formed in a part of the cylindrical wall portion of the case body. The battery case is characterized by

  That is, in the battery case according to the present invention, the metal plate is integrally fixed to at least the outer surface of the cylindrical wall portion of the synthetic resin case body having a bottomed cylindrical shape on one side. Therefore, excellent heat conductivity and high strength can be effectively exhibited while ensuring sufficient lightness.

  In the battery case according to the present invention, in particular, a part of the cylindrical wall portion of the case main body is an intrusion portion that is intruded into each of the through holes and the cylindrical extension portions of the metal plate. Thus, since the intrusion portion is fixed to the inner peripheral surfaces of the through holes and the cylindrical extension portions, the intrusion portions are respectively connected to the through holes and the cylindrical extension portions of the metal plate. The so-called angle effect that prevents the relative displacement between the cylindrical wall portion and the metal plate in the height direction of the cylindrical wall portion of the case body at such an intrusion portion. In addition to being able to be advantageously exhibited, when the case body is thermally expanded, the expansion of the cylindrical wall portion toward the opening side and the bottom wall portion side is caused by the respective through holes and the respective cylindrical extension portions. In the inner peripheral surface and the outer peripheral surface of each cylindrical extension portion, the opening side portion and the bottom wall portion side portion of the case body are regulated. So that may be.

  Moreover, in such a battery case, the through-hole and the cylindrical extension portion that exhibit a function of preventing the expansion in the height direction due to thermal expansion of the cylindrical wall portion are arranged in the height direction of the cylindrical wall portion with respect to the metal plate. A plurality of each is formed so as to be aligned in the corresponding direction. Therefore, the extension part which cross | intersects the height direction of a cylinder wall part simply by bending the both-sides edge part of the metal plate located in the opening part side and bottom wall part side of a case main body inside, respectively. However, one piece is provided at each of both end portions of the metal plate, and the extension of the cylindrical wall portion toward the opening portion due to thermal expansion is provided at the end portion of the metal plate located on the opening portion side of the case body. Another one provided at the end of the metal plate located on the bottom wall side of the case main body while preventing only the one extension part from extending to the bottom wall part side due to thermal expansion of the cylindrical wall part Compared to a battery case that is blocked only by the extension part of the tube wall, the extension of the cylinder wall part toward the opening and the bottom wall part due to the thermal expansion of the cylinder wall part respectively increase the height of the cylinder wall part. The plurality of through holes and the cylindrical extension portion can be more advantageously and reliably prevented at a plurality of positions in the vertical direction.

  Therefore, when the battery case according to the present invention is used, the cylinder of the case main body is generated in accordance with the temperature change of the atmosphere inside or around the battery in a state where the power generation element is accommodated in the accommodating portion and configured as a battery. It can be prevented very effectively that the metal plate is peeled off from the case body due to the wall portion being expanded and contracted by a larger amount than the metal plate. As a result, a highly reliable battery that can stably maintain the excellent battery performance realized by having sufficient lightness and high heat conductivity and strength is more reliably achieved. It will be obtained.

Aspects of the Invention

  By the way, the present invention can be suitably implemented at least in various aspects as listed below.

(1) A metal plate is formed by insert molding on at least the outer surface of the cylindrical wall portion of the case body made of synthetic resin, which has a cylindrical shape with a bottom on one side and that houses a power generation element. In the battery case configured to be integrally fixed, a plurality of through holes are provided in the metal plate so as to be arranged side by side in a direction corresponding to the height direction of the cylindrical wall portion of the case body, A cylindrical shape surrounding each of the plurality of through-holes is provided at each peripheral edge of each of the plurality of through-holes on the fixing surface of the metal plate with respect to the cylinder wall, and in the height direction of the cylinder wall. Cylindrical extending portions extending in the intersecting direction are integrally provided, and further, the inner peripheries of the through holes are inserted into the plurality of through holes and the plurality of cylindrical extending portions, respectively. Integrated with the surface and the inner peripheral surface of each cylindrical extension Battery case, characterized in that the fixation intrusion portion was formed at a portion of the cylindrical wall portion of the case body.

(2) In the aspect (1) described above, the distal end side portion of the cylindrical extension portion is provided with a bent portion that is bent or curved inside or outside the cylindrical extension portion, and the distal end side portion is provided. The entire cylindrical extension including the end face is embedded in the cylindrical wall of the case body.

  According to this aspect, the separation in the thickness direction between the metal plate and the case main body is advantageously prevented by the tip side portion rather than the curved portion of the cylindrical extension portion. Peeling of the plate can be effectively prevented.

  Moreover, in this aspect, it can prevent effectively that the front end surface of a cylindrical extension part is exposed outside. Therefore, for example, although an insulating film, plating, or the like is formed on the surface of the metal plate other than the tip surface of the cylindrical extension part, the cylinder extension part is formed from the process of forming the cylindrical extension part. Even if the insulating coating or plating is not formed on the tip surface of the cylindrical extension, the entire metal plate including the tip surface of the cylindrical extension has a short circuit, leakage, rust, etc. Can be advantageously prevented, and stabilization of battery performance can be advantageously achieved.

(3) In the aspect (1) or aspect (2) to be described above, the case main body in a state where at least two of the metal plates are opposed to each other with the accommodating portion of the case main body interposed therebetween The plurality of through-holes and the plurality of cylindrical extending portions are provided for each of the at least two metal plates. In this embodiment, as the metal plate, a plurality of types having different thicknesses and materials can be used. Therefore, for example, when the thickness of the cylindrical wall portion of the case body is partially different, the outer surface of the portion other than the thin portion is fixed to the outer surface of the thin portion while the relatively thick metal plate is fixed. In this case, it is possible to fix a thin metal plate, so that the lightness, strength, heat transfer property, etc. of the entire battery case can be appropriately secured in a balanced manner.

(4) In the aspect (3) described above, the metal plate portion located on the bottom wall portion side of the case main body is provided with a first inner curved portion that is bent or curved inside the case main body, An inner extension that extends from the first inner curved portion in a direction intersecting the height direction of the cylindrical wall portion of the case body at the tip side portion of the metal plate portion from the first inner curved portion. The part is formed. According to this aspect, in addition to the inner peripheral surface portion of each through hole and each cylindrical extension portion, the bottom wall portion due to thermal expansion of the cylindrical wall portion of the case body is also provided by the inner extension portion. Side extension can be advantageously prevented. Moreover, if such an inner extension portion is formed so as to extend substantially in parallel on the outer surface or inside of the bottom wall portion, for example, the inner extension portion enters the housing portion formed by the inner hole of the case body. It is made sufficiently long without being squeezed, so that extension of the cylindrical wall portion toward the bottom wall portion due to thermal expansion can be prevented more effectively. And as a result, due to the difference in expansion and contraction between the case main body and the metal plate due to temperature change, the metal plate can be more effectively prevented from peeling from the case main body. Become.

(5) In the aspect (4) described above, the end portion including the tip surface of the inner extension portion is embedded in the bottom wall portion of the case body. According to this aspect, for example, when a metal plate cut out from a plate-shaped metal material having an insulating film or plating formed on the surface is used, an insulating film or plating is formed. It is possible to effectively prevent the front end surface of the inner extending portion of the metal plate made of a cut surface that is not exposed from being exposed to the outside. Therefore, it is possible to advantageously prevent the occurrence of a short circuit, electric leakage, rust, or the like in the entire metal plate including the leading end surface, and it is possible to advantageously stabilize the battery performance.

(6) In the aspect (1) or aspect (2) described above, the cylindrical wall portion of the case body in a state where the metal plate is opposed to both sides with the housing portion of the case body interposed therebetween. A side portion fixed to the outer surface of the case body and a bottom portion fixed to the outer surface of the bottom wall portion of the case body, and the side portion includes the plurality of through holes and the plurality of the plurality of through holes. A cylindrical extension is provided. According to this aspect, the cylindrical wall portion of the case main body has a sufficiently long length with respect to the metal plate portion located on the bottom wall portion side of the case main body. Therefore, the extension of the case main body toward the bottom wall portion of the cylindrical wall portion can be more reliably prevented at the bottom portion.

(7) In any one of the above aspects (1) to (6), the metal plate portion positioned on the opening side of the case body is bent or curved inward of the case body. Two inner curved portions are provided, and the tip side portion of the metal plate portion includes the tip surface of the cylindrical wall portion on the opening side of the case main body. Be embedded in the edge. According to this aspect, for example, when a metal plate cut out from a plate-shaped metal material having an insulating film or plating formed on the surface is used, an insulating film or plating is formed. It is possible to effectively prevent the front end surface of the metal plate made of a cut surface that is not exposed from being exposed to the outside. Therefore, it is possible to advantageously prevent the occurrence of a short circuit, electric leakage, rust, or the like in the entire metal plate including the leading end surface, and it is possible to advantageously stabilize the battery performance.

  Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings.

  First, FIG. 1 to FIG. 3 schematically show an embodiment of a battery case according to the present invention in a front form, a planar form, and a longitudinal sectional form, respectively. As is clear from FIGS. 1 to 3, the battery case 10 of the present embodiment includes a case body 12 made of synthetic resin and two metal plates 14 that are integrally fixed to the outer surface of the case body 12. , 14.

  More specifically, the case main body 12 is made of a synthetic resin material having excellent heat resistance, chemical resistance, and the like, such as polypropylene and ABS resin. And as a whole, two rectangular lateral wall portions that are relatively thin and have a rectangular tube shape with a bottom on one side and have a sufficiently long length in a direction perpendicular to the height direction of the case body 12. A cylindrical wall portion 20 comprising 16a, 16b, and two rectangular vertical wall portions 18a, 18b having a short length in a direction perpendicular to the height direction of the case body 12, and under the cylindrical wall portion 20 A bottom wall portion 22 that closes the side opening portion is integrally provided.

  In addition, on the inner bottom surface of the bottom wall portion 22 of the case main body 12, two lateral wall portions 16a are provided at five locations at equal intervals in the length direction of the bottom wall portion 22 (left and right direction in FIG. 2). , 16b extending in the facing direction are integrally erected on both side end surfaces in the facing direction so as to be integrated with the inner side surfaces (the facing surfaces of each side wall portion 16). Yes. Thus, the interior of the case body 12 is partitioned by the five partition walls 24 into six spaces each having the opening 25 that opens upward. And each of these six spaces is made into the accommodating part 26 in which each well-known electric power generation element which is not shown in figure is accommodated. 1 to 3, reference numeral 28 denotes a reinforcing rib. For example, when a plurality of battery cases 10 are arranged in contact with each other at the lateral wall portions 16, the cooling between the battery cases 10 is performed. The air passage is formed for the purpose of improving the strength (rigidity) of the case body 12.

  On the other hand, the two metal plates 14 and 14 constituting the battery case 10 together with the case main body 12 are substantially the same length as the lateral wall portion 16 of the case main body 12 (in FIG. It is made of a rectangular thin flat plate having a dimension (direction dimension), a predetermined short width (dimension in the vertical direction in FIG. 1), and a sufficiently thin thickness. Further, the metal plate 14 is made of a metal material that is inexpensive and has sufficient strength, and further has excellent moldability by press molding or the like and a melting point higher than that of the synthetic resin material that gives the case body 12. Preferably used. Here, in particular, an iron plate, an aluminum plate, or the like that has these characteristics and can be elastically deformed is used as the metal plate 14.

  Then, such a metal plate 14 is opposite to the outer surface of each of the two lateral wall portions 16a and 16b in the cylindrical wall portion 20 of the case body 12, that is, the opposite surface of each lateral wall portion 16 to each other. This surface is integrally fixed by insert molding as will be described later in a state where most of one surface in the thickness direction is exposed to the outside.

  Thereby, in the battery case 10 of the present embodiment, the entire structure is a two-layer structure using a synthetic resin material and a metal material, which is sufficiently lighter than a battery case made of only a metal material. The two metal plates 14 and 14 fixed to the outer side surfaces of the two lateral wall portions 16a and 16b exhibit sufficiently higher rigidity than a battery case made of only a synthetic resin material, Furthermore, since most of each of the metal plates 14 is exposed to the outside, heat transfer through the metal plates 14 can be effectively ensured.

  By the way, in the present embodiment, in particular, two circular through holes 30 and 30 having the same diameter are spaced apart from each other by a predetermined distance in the width direction (height direction) at the intermediate portion in the length direction of the metal plate 14. It is formed to be located side by side. As shown in FIGS. 3 and 4, the opening inner peripheral portion of each of the two through holes 30, 30 on the fixing surface of the metal plate 14 with the cylindrical wall portion 20 has the same inner diameter as each through hole 30. A cylindrical extending portion 32 is integrally formed so as to individually surround each through-hole 30 and extend in a direction perpendicular to the height direction of the cylindrical wall portion 20, that is, in the horizontal direction. A curved portion 34 that bends or curves the cylindrical extension portion 32 inward is provided at an intermediate portion in the extending direction of the cylindrical extension portion 32, thereby the cylindrical extension portion. A portion on the tip side of the curved portion 34 of the 32 is coaxially positioned with respect to the through hole 30 and is formed as an annular inner flange portion 36 extending in the height direction of the cylindrical wall portion 20. A circular through hole 38 having a smaller diameter than the through hole 30 is formed in the inner hole of the annular inner flange portion 36.

  In other words, in the battery case 10 of the present embodiment, the opening 25 in the middle portion in the longitudinal direction of the horizontal wall portions 16a and 16b in the cylindrical wall portion 20 of the case body 12 is more than the central portion in the height direction. A circular recess that opens on a surface opposite to the fixing surface side of the cylindrical wall portion 20 with respect to the metal plate 14 portions positioned on the upper side serving as the side and the lower side serving as the bottom wall portion 22. Are provided one by one. The through hole 30 is formed at the opening in each of the two circular recesses, and the side wall portion of each circular recess is the cylindrical extension portion 32. The outer corner of the bottom of the circular recess is the bent portion 34. Further, the circular through hole 38 is provided at the center of the bottom of each circular recess, and the annular inner flange portion 36 is formed at the bottom of the circular recess surrounding the circular through hole 38. -ing

  Thus, a cylindrical inner regulating surface 40 made of a cylindrical surface extending horizontally with the same diameter is formed on the inner peripheral surface of each through hole 30 and the corresponding inner peripheral surface of each cylindrical extension portion 32. ing. In addition, a cylindrical outer regulating surface 42 formed of a cylindrical surface extending horizontally with the same diameter is formed on the outer peripheral surface of the cylindrical extension portion 32. Two pairs of such a cylindrical inner regulating surface 40 and a cylindrical outer regulating surface 42 pair with each other, and the metal of the through-hole 30 and the cylindrical extension portion 32 with respect to the metal plate 14. Corresponding to the formation position on the plate 14, it is provided so as to be lined up at a predetermined distance in the height direction of the cylindrical wall portion 20 of the case body 12. Here, the extension lengths of the cylindrical inner regulating surface 40 and the cylindrical outer regulating surface 42 in the horizontal direction are both equal to half the thickness of the cylindrical wall portion 20 (lateral wall portion 16). The predetermined dimension is larger than that.

  Further, in the battery case 10, the entire cylindrical extension portion 32 formed integrally with the metal plate 14 is embedded in the cylindrical wall portion 20 of the case body 12. That is, in other words, in the cylindrical wall portion 20 of the case body 12, two portions corresponding to the cylindrical extending portions 32, 32 provided at the two upper and lower portions of the metal plate 14 are respectively cylindrically extended. Each cylindrical extension 32 is penetrated through each circular through-hole 38 of the outlet 32. These two parts are referred to as intrusion parts 44 and 44, respectively. As a result, the cylindrical wall portion 20 (lateral wall portion 16) is circular at the two intrusion sites 44, the entire surface of the cylindrical inner regulating surface 40, the entire surface of the annular inner flange portion 36 on the through hole 30 side, and the circular shape. The cylindrical outer regulating surface 42 is integrally fixed to the entire inner peripheral surface of the through-hole 38 and is located around each of the two intrusion portions 44, 44. And the entire inner surface of the annular inner flange portion 36 opposite to the through hole 30 side are integrally fixed to each other.

  Thus, in the present embodiment, the cylindrical wall portion 20, particularly the vertical direction between the lateral wall portion 16 and the metal plate 14, and the cylindrical wall portion due to the angle effect due to the two intrusion sites 44 in the cylindrical wall portion 20 of the case body 12. The relative displacement in the thickness direction of 20 is prevented. In addition, expansion of the cylindrical wall portion 20, particularly the lateral wall portion 16, toward the opening 25 (upper side) due to thermal expansion mainly includes two cylindrical inner restrictions that are fixed to the two intrusion portions 44 and 44, respectively. The upper side portion of each of the surfaces 40, 40 and the lower side portion of each of the two cylindrical outer restriction surfaces 42, 42 fixed to the peripheral portions of the two intrusion portions 44, 44 are regulated. To be able to be. Further, at the same time, the expansion of the cylindrical wall portion 20, particularly the lateral wall portion 16, toward the bottom wall portion 22 (downward) due to thermal expansion is mainly fixed to the two intrusion portions 44, 44 respectively. Lower cylindrical portions of the cylindrical inner restricting surfaces 40, 40 and upper portions of the two cylindrical outer restricting surfaces 42, 42 fixed to the peripheral portions of the two intrusion portions 44, 44, respectively. It can be regulated by the part.

  Further, in such a metal plate 14 in which two cylindrical inner regulating surfaces 40 and two cylindrical outer regulating surfaces 42 are provided in the middle portion in the height direction (width direction), the bottom wall portion of the case body 12 is provided. A lower end inner curved portion 46 as a first inner curved portion that is bent at a substantially right angle toward the inner side of the case main body 12 is provided at the lower end portion located on the 22 side. And here, the outer side surface of the bottom wall part 22 in which such a lower end inner side curved part 46 was made into the same surface as the outer side surface of the horizontal wall part 16 in the cylinder wall part 20 among the lower side edge parts of the metal plate 14. It is formed in the fixed part with respect to.

  Thus, of the lower end portion of the metal plate 14, the entire portion on the tip side (lower side) of the lower end inner curved portion 46 extends from the outer surface of the bottom wall portion 22 of the case body 12 into the bottom wall portion 22. The lower end inner extension portion 48 extends horizontally to the vicinity of the center portion in the width direction of the bottom wall portion 22. In other words, the lower end inner extending portion 48 is orthogonal to the height direction of the cylindrical wall portion 20 of the case main body 12 in a state where the entire lower end extending portion 48 is embedded in the bottom wall portion 22 of the case main body 12. In this direction, the cylindrical wall portion 20 is extended with a length exceeding the thickness dimension of the lateral wall portion 16. Therefore, here, the extension of the cylindrical wall portion 20 of the case body 10, particularly the lateral wall portion 16, to the bottom wall portion 22 side (downward side) due to the thermal expansion can be restricted by the lower end inner extension portion 48. It is like that.

  On the other hand, at the upper end portion of the metal plate 14, a first curved portion 50 as a second inner curved portion, which is bent at a substantially right angle toward the inside of the case body 12, and the first curved portion 50. A second bent portion 52 that is bent at a substantially right angle toward the upper side is also provided at the tip side portion. As a result, a step portion 54 that extends horizontally inward is provided at the upper end portion of the metal plate 14, and a straight portion that further extends straight above the upper end portion of the metal plate 14 and further on the inner side of the other portions. 56. The whole including the front end surface of the straight portion 56 is embedded in the upper end portion of the cylindrical wall portion 20.

  By the way, the battery case 10 of the present embodiment having such a structure is easily manufactured by, for example, performing the following insert molding.

  That is, first, two metal plates 14 and 14 are prepared. For this purpose, first, for example, two long rectangular metal base plates are cut out from a plate-shaped metal material having an electrically insulating film or plating formed on the surface. Thereafter, for each of these two metal base plates, the two circular through holes 38, 38 are arranged at a predetermined distance in the width direction in the middle portion in the length direction, for example, It is formed by a known punching molding or the like. Next, for example, stretch flange molding (burring process) or the like is performed on each of the formation portions of the two circular through holes 38, 38 in each metal base plate, and the circular through hole 38 is formed in the center of the bottom. A circular recess having a predetermined depth is provided. Thereby, the through hole 30 is formed at the opening of each circular recess, and the annular flange portion 36 is formed at the bottom of each circular recess surrounding the through hole 30.

  Then, a known press bending process or the like is performed on each of the two metal base plates, and a lower end inner curved portion 46 is provided on one end side in the width direction of each metal base plate. The tip side portion is a lower end inner extension portion 48. Moreover, the 1st curved part 50 and the 2nd curved part 52 are formed in the other end side of the width direction of each metal base plate, and the front-end | tip part of this other end side is made into the straight part 56. FIG. As a result, the target two metal plates 14 and 14 are respectively prepared and prepared.

  Then, as shown in FIG. 5, the two metal plates 14 and 14 thus obtained are set in a molding cavity 60 of an injection molding die 58 prepared in advance.

  The injection mold 58 used here is, for example, a fixed plate 62 and a movable plate 64 arranged opposite to each other in the horizontal direction, and on the opposing surfaces of the fixed plate 62 and the movable plate 64, respectively. It has a fixed mold 66 and a movable mold 68 arranged to be fixed in position. A cavity forming convex portion 70 is integrally formed on the surface of the fixed mold 66 facing the movable mold 68, while a cavity forming recess 72 is provided on the surface of the movable mold 68 facing the fixed mold 66. It has been.

  In the injection mold 58, the fixed mold 66 and the movable mold 68 are matched to each other so that the cavity forming convex portion 70 enters the cavity forming recess 72, and the cavities are formed. A molding cavity 60 corresponding to the outer shape of the battery case 10 is formed between the inner surface of the forming recess 72 and the outer surface of the cavity forming convex portion 70. Further, under such a state where the fixed mold 66 and the movable mold 68 are aligned, the sprue 76 of the sprue bush 74 provided on the fixed platen 62 and brought into contact with a nozzle of an injection molding machine (not shown) is fixed to the fixed mold 66. In addition, the mold can be communicated with the molding cavity 60 through a sub sprue 78, a runner 80, and a gate 82 provided in the movable mold 68.

  Further, when the two metal plates 14 and 14 are set in the molding cavity 60 of the injection mold 58, the two metal plates 14 and 14 sandwich the cavity forming convex portion 70 therebetween. The straight portions 56 of the respective metal plates 14 are positioned on the opening side of the cavity forming recess 72 while being opposed to each other, and the lower end inner extending portion 48 is the tip end surface of the cavity forming convex portion 70. The portion from the lower end inner curved portion 46 to the first curved portion 50 is a surface opposite to the extending side of the lower end inner extending portion 48. Is in contact with the inner surface of the cavity forming recess 72.

  Then, when the two metal plates 14 and 14 are set in the molding cavity 60 in this manner, as shown in FIG. 6, a predetermined molten resin material 84 is fed from a nozzle of an injection molding machine (not shown). The sprue 76, the sub sprue 78, the runner 80, and the gate 82 are injected into the molding cavity 60 and filled.

  Thereafter, in the molding cavity 60, the molten resin material 84 injected and filled therein is cooled and solidified to form the case body 10, and each of the two lateral wall portions 16a and 16b of the case body 10 is molded. The two metal plates 14 are fixed to each other on the outer surface. Thus, the intended battery case 10 is obtained.

  Thus, in the battery case 10 of the present embodiment that can be easily obtained by performing the insert molding, the opening 25 side (upper side) due to the thermal expansion of the cylindrical wall portion 20 of the case body 10, particularly the lateral wall portion 16. The two cylindrical inner sides formed corresponding to the through holes 30 and 30 and the cylindrical extension portions 32 and 32 provided in pairs in the height direction of the cylindrical wall portion 20. The upper and lower portions of the restricting surfaces 40 and 40 and the lower portions of the two cylindrical outer restricting surfaces 42 and 42 can be restricted. Further, the expansion of the cylindrical wall portion 20 of the case main body 10, particularly the bottom wall portion 22 side (downward side) due to the thermal expansion of the side wall portion 16, the lower side portions of the two cylindrical inner regulating surfaces 40, 40. And can be regulated by the respective upper side portions of the two cylindrical outer regulating surfaces 42, 42. Further, the extension of the lateral wall portion 16 toward the bottom wall portion 22 side extends from the outer surface of the lateral wall portion 16 in the tubular wall portion 20 to the intermediate portion in the width direction of the bottom wall portion 22 beyond the thickness of the lateral wall portion 16. The lower end inner extending portion 48 that extends in a direction perpendicular to the height direction of the cylindrical wall portion 20 with a sufficient length to reach can be advantageously regulated.

  Thus, in such a battery case 10, two through holes provided in the height direction of the cylindrical wall portion 20 of the case main body 12 caused by thermal expansion are provided side by side in the height direction of the cylindrical wall portion 20. 30 and 30 and the cylindrical extending portions 32 and 32, two cylindrical inner restricting surfaces 40 and 40, two cylindrical outer restricting surfaces 42 and 42, and a lower end inner extending portion 48 are formed. Can be advantageously prevented at a plurality of positions in the height direction of the cylindrical wall portion 20 by the cooperative action.

  In addition, in the present embodiment, the two intrusion portions 44, 44, which are part of the cylindrical wall portion 20 of the case body 12, are formed in the two cylindrical extension portions 32, 32 formed integrally with the metal plate 14. And are fixed to the entire surface of the cylindrical inner regulating surface 40 and the entire surface on the opening 25 side of the annular inner flange portion 36 provided at the tip of each cylindrical extension portion 32. Therefore, the respective intrusion sites 44 are brought into a state of being engaged with the cylindrical inner regulating surface 40 and the surface of the annular inner flange portion 36 on the opening 25 side, The angle effect that prevents relative displacement between the cylindrical wall portion 20 and the metal plate 14 in both the height direction and the thickness direction of the cylindrical wall portion 20 can be advantageously exerted by 44.

  Therefore, in such a battery case 10, when the battery case 10 is configured as a secondary battery or the like, the cylindrical wall portion 20 of the case main body 12 is made of metal along with the temperature change of the atmosphere inside and around the battery. It is possible to prevent the metal plate 14 from peeling from the case body 12 extremely reliably and effectively due to being expanded and contracted by an amount larger than that of the plate 14.

  Therefore, by using the battery case 10 of the present embodiment as described above, excellent battery performance realized by having sufficient lightness and high heat conductivity and strength can be stably maintained. A highly reliable battery can be manufactured more reliably and more advantageously.

  Further, in the battery case 10, the entire cylindrical extension portion 32 including the inner peripheral surface of each circular through hole 38, the entire straight portion 48 including the upper end surface of the metal plate 14, and the lower end surface thereof. The entire lower end inner extension portion 48 is embedded in the middle portion, the upper end portion, and the lower end portion in the height direction of the lateral wall portion 16 in the case body 10. Therefore, for example, when the circular plate 38 is formed by punching or the like even when the metal plate 14 has an electrically insulating film or plating on the surface, the metal plate 14 is predetermined. Therefore, the inner peripheral surface of the circular through-hole 38 and the upper and lower end surfaces of the metal plate 14 are not exposed to the outside. Such exposure can be advantageously avoided. As a result, a part of the metal plate 14 may be rusted or short-circuited by exposure to the outside of the metal plate 14 portion on which no electrically insulating film or plating is formed. Therefore, excellent battery performance can be stabilized more effectively.

  Next, in FIG. 7, the structure for restricting the extension in the height direction due to the thermal expansion of the cylindrical wall portion 20 of the case body 12, which is given to the metal plate 14, is the first embodiment. Some different examples are shown. In the embodiment shown in FIG. 7, members and parts having the same structure as in the first embodiment are given the same reference numerals as those in FIGS. Omitted.

  That is, in the battery case 10 shown in FIG. 7, the metal plate 14 that is integrally fixed to the outer surface of each of the two lateral wall portions 16 a and 16 b in the cylindrical wall portion 20 of the case body 10 includes: It is composed of a single plate material.

  That is, in the present embodiment, the metal plate 14 has a U-shaped longitudinal section, and for example, a form in which one rectangular plate material is bent at right angles in the same direction at two places in the width direction. have. In other words, the metal plate 14 has two side portions 86a and 86b facing each other, and a bottom portion 88 extending between the lower ends of the two side portions 86a and 86b so as to connect them. Are integrally formed. Further, in the metal plate 14, the through-hole 30, the cylindrical extension portion 32, and the annular flange portion 36 are provided at two locations that are separated from each other by a predetermined distance in the height direction at the intermediate portion in the length direction of each side portion 86. And the circular through hole 38 are provided in the same state as in the first embodiment, and the bottom portion 88 is large enough to cover the entire outer bottom surface of the bottom wall portion 22 of the case body 12. And is configured.

  And such a metal plate 14 has each cylindrical extension part 32 and each annular flange part 36 embedded in the two horizontal wall parts 16a and 16b in the case main body 12, those two pieces. The side portions 86a and 86b are integrally fixed to the outer side surfaces of the two lateral wall portions 16a and 16b, respectively, and the bottom portion 88 is fixed to the outer bottom surface of the bottom wall portion 22 of the case body 12. It is fixed together.

  Thus, here, the intrusion site 44, which is a part of each lateral wall portion 16 of the case body 12, enters each cylindrical extension portion 32 through each circular through hole 38, and each cylindrical inner regulating surface 40. In addition, the peripheral portion of the intrusion portion 44 in each lateral wall portion 16 is integrally fixed to each cylindrical outer regulating surface 42. In addition, the two corners on the bottom 88 side of the metal plate 14 having a U-shaped longitudinal section are respectively set as the lower end inner curved portion 46, and the bottom portion 88 extends from the lower end inner curved portion 34 to the case. The lower end inner extending portion 48 extends in a direction intersecting with the height direction of the cylindrical wall portion 20 of the main body 12.

  Accordingly, also in the present embodiment, the cylindrical wall portion 20 of the case body 12 is obtained by the cooperative action of the cylindrical inner regulating surface 40, the cylindrical outer regulating surface 42, and the lower end inner extending portion 48 including the bottom portion 88. Elongation in the height direction due to thermal expansion of can be advantageously prevented.

  Therefore, even in the battery case 10 of the present embodiment as described above, the same effect as that of the first embodiment can be enjoyed effectively.

  In particular, in the present embodiment, the entire outer bottom surface of the bottom wall portion 22 of the case body 12 is covered with the bottom portion 88 of the metal plate 14, so that the bottom inner extension extending from the bottom portion 88 is extended. The length of the protruding portion 48 can be secured more sufficiently, and the extension of the cylindrical wall portion 20 of the case body 12 to the bottom wall portion 22 side due to thermal expansion can be prevented more effectively and reliably. In addition, the exposed area of the metal plate 14 to the outside is effectively increased, whereby the heat transfer performance of the battery case 10 that is greatly influenced by the exposed area of the metal plate 14 to the outside is efficiently enhanced. The advantage of obtaining is also obtained.

  The specific configuration of the present invention has been described in detail above. However, this is merely an example, and the present invention is not limited by the above description.

  For example, in the two embodiments, the through hole and the cylindrical extension portion provided in the metal plate are each circular or cylindrical, but the shape of the through hole and the cylindrical extension portion is as follows. However, the present invention is not limited to this. For example, the through-hole can be oval, polygonal, or indefinite, and the cylindrical extension can correspond to the shape of the through-hole or can be elliptical regardless of the shape of the through-hole. It is good also as a cylinder shape or a rectangular tube shape.

  Further, the formation position and the number of the through-holes and the cylindrical extension portion with respect to the metal plate are not particularly limited to those shown in the two embodiments, and the cylinder of the case main body is not limited to the metal plate. It suffices if a plurality are provided so as to be arranged side by side in a direction corresponding to the height direction of the wall portion.

  Furthermore, in the said embodiment, the recessed part opened in the surface on the opposite side to the fixed surface to the cylindrical wall part 20 of the case main body 12 with respect to the metal plate 14 is provided, and it penetrates in the opening part of this recessed part. While the hole 30 is provided and the cylindrical extension 32 as the cylindrical extension is formed at the side wall of the recess, for example, the through hole 30 is provided on the metal plate 14. The cylindrical body made of a member different from the metal plate 14 having a shape surrounding the through hole 30 is penetrated on the surface opposite to the fixing surface of the metal plate 14 fixed to the cylindrical wall portion 20 of the case body 12. The cylindrical extension can be integrally formed with the metal plate 14 by being integrally joined to the opening peripheral edge of the hole 30 by adhesion or welding. It goes without saying that the method of forming such a cylindrical extension or through hole is not limited in any way.

  Moreover, in the said embodiment, although the metal plate 14 was integrally fixed only with respect to only the two horizontal wall parts 16a and 16b in the cylinder wall part 20 of the case main body 12, metal plate 14 is attached to a cylinder wall part. Of course, the two vertical wall portions 18a and 18b in FIG.

  Furthermore, the entire shape of the case main body 12 may be a rectangular tube shape other than the rectangular tube shape illustrated in FIG.

  Furthermore, in the first embodiment, the two metal plates 14 and 14 are both made of the same type of metal material with the same thickness. Even if the constituent materials are different from each other, there is no problem. For example, when the thickness of the cylindrical wall portion 20 portion of the case body 12 to which the respective metal plates 14 are integrally fixed is different, a plurality of metal plates 14 having different thicknesses are advantageously used. It is done. That is, the thick metal plate 14 is integrally fixed to the thin cylindrical wall portion 20, while the thin metal plate 14 is integrally fixed to the thick cylindrical wall portion 20. . Thereby, the advantage that the lightness, strength, heat transfer property, etc. in the battery case 10 as a whole can be appropriately secured in a balanced manner can be obtained.

  In addition, it goes without saying that the battery case according to the present invention can be applied to both the battery case of the secondary battery and the battery case of the primary battery.

  In addition, although not enumerated one by one, the present invention can be carried out in a mode to which various changes, modifications, improvements, etc. are added based on the knowledge of those skilled in the art. It goes without saying that all are included in the scope of the present invention without departing from the spirit of the present invention.

It is front explanatory drawing which shows one Embodiment of the battery case according to this invention. FIG. 2 is an explanatory plan view of the battery case shown in FIG. 1. It is III-III cross-section expansion explanatory drawing in FIG. FIG. 4 is a partially enlarged explanatory view in FIG. 3. It is explanatory drawing which shows an example of the process of manufacturing the battery case shown by FIG. 1, Comprising: The state which set the metal plate in the shaping | molding cavity is shown. It is explanatory drawing which shows the example of the manufacturing process of the battery case performed following FIG. 5, Comprising: The state which injected and filled the molten resin material in the shaping | molding cavity in which the metal plate was set is shown. It is a figure corresponding to FIG. 3 which shows another embodiment of the battery case according to this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Battery case 12 Case main body 14 Metal plate 20 Cylinder wall part 22 Bottom wall part 25 Opening part 30 Through-hole 32 Cylindrical extension part 40 Cylindrical inner side regulation surface 42 Cylindrical outer side regulation surface 44 Intrusion site 48 Lower end inner side extension part

Claims (7)

A metal plate is integrally formed by insert molding on at least the outer surface of the cylindrical wall portion of the synthetic resin case body having a cylindrical shape with a bottom on one side and containing a power generation element inside. In the battery case that is made to adhere,
A plurality of through holes are provided in the metal plate so as to be positioned side by side in a direction corresponding to the height direction of the cylindrical wall portion of the case body, and the metal plate is fixed to the fixing surface of the metal plate with respect to the cylindrical wall portion. A cylindrical extending portion extending in a direction intersecting the height direction of the cylindrical wall portion has a cylindrical shape surrounding each of the plurality of through holes separately at each peripheral edge portion of the plurality of through holes. Provided integrally, and further penetrated into each of the plurality of through holes and the plurality of cylindrical extending portions, and the inner peripheral surface of each of the through holes and the inner peripheral surface of each of the cylindrical extending portions. A battery case characterized in that an intrusion portion integrally fixed to each other is formed at a part of a cylindrical wall portion of the case body.   A bent portion that is bent or curved on the inside or outside of the cylindrical extension portion is provided at the tip side portion of the cylindrical extension portion, and the cylindrical extension portion including the end face of the tip side portion is provided. The battery case according to claim 1, wherein the battery case is entirely embedded in the cylindrical wall portion of the case body.   At least two of the metal plates are fixed to the outer surface of the cylindrical wall portion of the case body in a state of being opposed to both sides with the accommodating portion of the case body interposed therebetween, and at least The battery case according to claim 1 or 2, wherein the plurality of through holes and the plurality of cylindrical extending portions are provided for each of the two metal plates.   The metal plate portion positioned on the bottom wall portion side of the case main body is provided with a first inner curved portion that is bent or curved inside the case main body, and the first inner curved portion in the metal plate portion is provided. The inner extension part extended in the direction which cross | intersects the height direction of the cylindrical wall part of this case main body from this 1st inner side curved part is formed in the front end side part rather than a part. Battery case.   The battery case according to claim 4, wherein an end portion including a front end surface of the inner extending portion is embedded in the bottom wall portion of the case main body.   The metal plate is fixed to the outer surface of the cylindrical wall portion of the case body in a state of being opposed to both sides with the housing portion of the case body interposed therebetween, and the bottom of the case body The bottom part fixed to the outer surface of the wall part is integrally provided, and the plurality of through holes and the plurality of cylindrical extension parts are provided on the side part. Item 3. The battery case according to Item 2. The metal plate portion located on the opening side of the case main body is provided with a second inner curved portion that is bent or curved inside the case main body, and the second inner curved portion in the metal plate portion is provided. The tip end portion is embedded in the end portion of the cylindrical wall portion on the opening side of the case main body in a whole including the tip end surface thereof. Battery case as described in.

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