JP5154075B2 - Storage case for secondary battery pack and manufacturing apparatus thereof - Google Patents

Description

  The present invention relates to a storage case for a square box-shaped secondary battery pack composed of a lower case to be a storage case formed by resin molding, and an apparatus for manufacturing the same.

  In recent years, due to the expansion of integrated circuits due to higher functionality of mobile communication devices that are power supply devices, the mounted devices have become smaller and lighter in size, digital still cameras have become smaller and lighter, and portable music players have become thinner and lighter. There is a strong demand for thinner and lighter secondary battery packs, which are power supplies, in particular.

  Storage boxes for secondary battery packs having a rectangular box shape and a thickness of 3 mm to 10 mm used for conventional communication devices often have a thickness of 0.3 mm or more at the bottom of the longitudinal section relative to the thickness. In order to increase the battery capacity against the thinning of the battery pack itself, the size of the components that make up the secondary battery pack is reduced, especially the storage case for the metal case of the secondary battery itself and the pack with an insulating function formed of resin. It was indispensable to reduce the wall thickness.

  As shown in FIG. 8, the pack storage case includes an upper case 202 and a lower case 203 formed by resin molding for storing the secondary battery 201 as shown in FIG. There has been proposed a structure in which the thickness of the upper bottom surface portion 204 and the lower bottom surface portion 205 is 0.3 mm or less in both the upper case 202 and the lower case 203 (see, for example, Patent Document 1).

  In addition, in order to mold a molded product including a thin portion having a thickness of 0.3 mm or less in the storage case of the secondary battery pack, a method of filling the resin at a high speed so that the molten resin spreads over the entire resin molding die Alternatively, in order to reduce the melt viscosity of the resin and increase the fluidity of the resin, a method of molding at a resin temperature exceeding the upper limit of the resin manufacturer's recommended temperature at the time of resin molding is used. Some are.

  In this general injection molding method, as shown in FIG. 9, a high-speed molding machine with an injection speed of 1000 mm / second to 2000 mm / second is used to fill the resin at a high speed with the resin. The inside of two resin molding dies 315, which is a typical side-gate type of injection molding dies used in these high-speed molding machines, is provided as an air vent and has a porous structure with a minute cavity inside. A member using the object is placed in the fixed mold 312 and the movable mold 313, and the gas generated when the resin is filled into the molded product shape portion 314 from the filling path 311 at high speed is generated by the fixed mold 312 and the movable mold 313. Among them, there has been proposed one having a minute hole necessary for discharging (see, for example, Patent Document 2).

Furthermore, at the time of resin filling, the thickness of the thin part is set to be thicker than the thickness at the time of product completion, the resin is filled in the resin molding die, and then when the resin filling is completed or filling There has been proposed a method of injection compression molding to obtain a thin-walled molded product by moving the insert of a resin molding die for forming a thin-walled portion by a hydraulic mechanism or an extrusion mechanism of a molding machine immediately before completion (for example, Patent Documents) 3).
JP 2001-58332 A JP 2004-90308 A JP 2003-159735 A

  However, in Patent Document 1 of the above-described prior art, the thickness of the upper bottom surface portion 204 and the lower bottom surface portion 205 shown in FIG. 8 is increased as the size of the secondary battery increases for the purpose of increasing the capacity of the secondary battery. It is necessary to further reduce the thickness, and as the thickness of the thin portions of the upper bottom surface portion 204 and the lower bottom surface portion 205 decreases, the strength of the bottom surface portion is impaired, and it can withstand external pressure as a storage case for a secondary battery pack. Becomes difficult. For this reason, the bottom part of the upper or lower case molded thinly at 0.3 mm or less, particularly 0.25 mm or less, has a large amount of deflection with respect to external pressure, and is stored as a required specification of a storage case for a secondary battery pack. There is a problem that the function of protecting the secondary battery 201 is not satisfied, which is a barrier for increasing the capacity.

  Moreover, in patent document 2, the injection | pouring which used the porous member with which the inside provided as an air vent of the stationary mold 312 and the movable mold 313 which comprise the resin mold 315 became a micro cavity was used. When filling is performed at a high speed of 1000 mm / second to 2000 mm / second, only the minute hollow portion provided as an air vent inside the resin molding die 315 is compressed by the internal pressure generated by the generated resin. For this reason, there is a problem that it is difficult to mold to a necessary thickness at the time of filling, and in particular, there are those in which minute holes are transferred to the surface of the resin molded product and the product specification is not satisfied.

  The present invention has been made in view of the above problems, and realizes a reduction in the thickness of the storage case of the secondary battery pack in spite of ensuring the strength capable of protecting the stored secondary battery from external pressure. In addition, when molding a thin case, it is easy to fill the resin inside the thin mold and realize a stable thickness of the storage case for the secondary battery pack, resulting in high quality and high productivity. It is an object of the present invention to provide a storage case for a secondary battery pack and an apparatus for manufacturing the same.

The storage case of the pack for a secondary battery of the present invention to solve the above object, consists second case to be joined with the first case and the first case for accommodating at least two batteries A storage case for a secondary battery pack, wherein the first case has a bottom surface and a side surface around the bottom surface, and is disposed in an inner side direction in which the secondary battery is stored at the center of the bottom surface. It is characterized by providing a rib part.

  According to the present invention, by using a storage case for a secondary battery pack having a rib portion at the center of the bottom case of a lower case that is a rectangular box-shaped storage container and the upper case joined to the lower case, A high-capacity secondary battery that can ensure high strength at the center rib portion of the battery pack and can reduce the thickness of the bottom of the storage case of the secondary battery pack, thereby further increasing the size of the stored battery. A pack can be realized. In addition, even when external pressure is applied to the bottom surface portion, it is possible to minimize the deflection of the bottom surface portion that has been thinned and to ensure high strength.

  According to a first aspect of the present invention, there is provided a storage case for a secondary battery pack comprising a lower case for storing a secondary battery and an upper case joined to the lower case, wherein the square box is made of resin. By having a rib part at the center of the bottom of the shape, it is possible to ensure high strength at the center of the bottom of the bottom, and it can be made thinner than the thickness of the bottom of the storage case of a conventional secondary battery pack The storage capacity of the pack storage case can be increased, and when the external pressure is applied to the bottom surface, it is possible to minimize the deflection of the thinned bottom surface and ensure high strength. Become.

In the second invention of the present invention, the rib portion is isotropic, and the height of the convex and concave portions in the longitudinal section is thicker than the thickness of the bottom of the rectangular box-shaped storage container formed of resin. By adopting a shape that protrudes in the direction, high strength can be ensured by the rib part at the center of the bottom, and external pressure is applied to the bottom even though the bottom of the storage case for the secondary battery pack is thin. Even when it is received by the part, it is possible to minimize the deflection of the bottom part.

  In the third invention of the present invention, the rib portion is isotropic, and the height of the convex and concave portions in the longitudinal section is the same as the thickness of the bottom surface of the rectangular box-shaped storage container made of resin. As a result, the rib portion has a high strength at the center of the bottom surface, the thickness of the bottom surface of the storage case of the secondary battery pack can be reduced, the deflection at the bottom surface can be suppressed, and a high strength can be ensured.

  According to a fourth aspect of the present invention, there is provided an apparatus for manufacturing a storage case for a secondary battery pack comprising at least a lower case for storing a secondary battery and an upper case joined to the lower case. And a movable movable mold that is provided so as to be movable toward and away from the fixed mold, and a thin-walled mold connected to an injection molding section for resin molding, and a rib molding section inside the movable mold And a cooling part connected to the nest, and a gas exhaust means, so that a high strength is ensured by a rib part at the center of the bottom surface of the storage case of the secondary battery pack. The thickness of the bottom surface can be reduced, the injection speed can be filled at high speed, the thickness of the storage case of the secondary battery pack can be made uniform, and the bottom surface of the storage case of the secondary battery pack That minute holes are transferred to Improvement of fried productivity and quality can be achieved.

  In the fifth invention of the present invention, the gas is exhausted by only forced exhaust inside the thin mold because the gas is exhausted by the rib forming portion of the nest provided in the movable mold. Can be efficiently exhausted, and a stable thin thickness can be formed.

  In the sixth aspect of the present invention, the structure is such that the gas exhaust means is connected to the nested rib forming portion provided in the movable mold, whereby the gas is efficiently exhausted into the thin-walled mold. The formation of a nest due to air bubbles on the bottom surface of the storage case of the battery pack can be suppressed, and the storage case of the secondary battery pack can be formed with sufficient strength.

  In the seventh aspect of the present invention, since the nest rib forming portion provided in the movable mold is formed in an isotropic shape, stable gas can be exhausted and productivity and quality can be improved. Is possible.

  In the eighth aspect of the present invention, the gas is accumulated in the thin molding die by injecting the gas from all directions when filling the resin with the nested rib molding portion provided in the movable die. At the same time, it is possible to exhaust and suppress the formation of nests that occur during resin filling.

  In the ninth invention of the present invention, the strength of the bottom surface of the storage case of the rechargeable battery pack is ensured by making the isotropic rib molding part into a spiral shape, and the gas in the thin mold is efficiently Can be discharged.

  According to the tenth aspect of the present invention, the isotropic rib forming portion has a mesh shape, so that the cost for producing the exhaust groove can be reduced, and the gas in the thin molding die is efficiently discharged. It becomes possible.

  In the eleventh aspect of the present invention, the gas exhaust means connects the air vent and the forced exhaust section via the gas exhaust path provided along the surface of the nest connected to the nest rib forming section provided in the movable mold. It is possible to efficiently and forcibly exhaust the gas inside the thin mold, and to suppress the formation of nests due to bubbles on the bottom surface of the storage case of the secondary battery pack. .

In the twelfth aspect of the present invention, the gas exhaust means is provided in the movable mold from the cross-sectional area of the gas discharge portion provided along the surface of the nesting connected to the rib forming portion of the nesting provided in the movable mold. By increasing the cross-sectional area of the air vent, the pressure difference is instantaneously generated to increase the flow velocity during suction, accelerate the transition to the vacuum state, and efficiently exhaust the gas inside the thin mold. It is possible to suppress the occurrence of nests due to bubbles without burrs at the rib tip provided on the bottom surface of the storage case of the secondary battery pack.

  The best mode for carrying out the present invention will be described below with reference to the drawings. An embodiment shown below shows a manufacturing apparatus listed for explaining the present invention, and the present invention provides a storage battery structure and manufacturing apparatus for a secondary battery pack as follows. Not specific.

  FIG. 1 is a perspective view of a storage case for a secondary battery pack according to an embodiment of the present invention. As shown in FIG. 1, the lower case 1 and the rib portion 2 will be described as an example. The rib portion 2 is formed in an isotropic mesh shape at the center of the bottom surface of the lower case 1, and the height of the concavo-convex convex portion relative to the longitudinal section of the rib portion 2 is thicker than the thickness of the bottom surface of the lower case 1. This structure has a shape protruding in the horizontal direction and suppresses and reinforces the deflection when the bottom surface portion receives external pressure. Further, the height of the convex portion of the concavo-convex shape with respect to the longitudinal section of the rib portion 2 is the same as the thickness of the bottom surface of the lower case 1, that is, even if a groove is carved on the bottom surface of the lower case 1. I do not care. The upper case may have the same structure.

  This is a function of a supporting beam that can form an isotropic mesh to increase the strength of the bottom surface part that is the target of its strength and can withstand the pressure received from the outside perpendicular to the bottom surface part. Plays. Further, the rib portion 2 has a function of reducing the warpage of the shape due to an internal stress difference or a shrinkage difference during resin molding. Further, the rib portion 2 may have a spiral shape as long as it has isotropic properties.

  Next, FIG. 2 is a schematic diagram of a cross section of a thin-walled mold according to an embodiment of the present invention. As shown in FIG. 2, for resin molding comprising a fixed mold 11 connected to an injection molding part 31 for sending out molten resin, and a movable mold 12 provided opposite to the fixed mold 11 and detachably provided. The lower case 1 of the storage case of the secondary battery pack shown in FIG.

  Further, the lower case 1 is formed by a molding part 14 in a space provided between the fixed mold 11 and the movable mold 12, and the lower case 1 is formed at the center of the movable mold 12 as shown in FIG. The insert 13 having the rib forming portion 18 is arranged. In the present invention, the rib forming portion 18 provided in the insert 13 is also used as a gas exhaust groove for exhausting gas.

  As shown in FIG. 2, the rib forming portion 18 provided in the insert 13 is provided with only a slight gap on the surface where the inserts 13 are in contact with each other, and the gap is communicated with the air vent 17 as a gas discharge path 19. In addition, the air vent 17 is connected to the forced exhaust part 32, and quickly and instantaneously discharges the gas that causes trouble in the space portion to be replaced with the resin when filling the resin from the thin mold 30. In addition, a cooling pipe 15 is built in the insert 13, and the cooling pipe 15 is connected to the cooling unit 20 to keep the thin molding die 30 at a constant temperature.

  The above configuration will be described in detail with reference to FIG. First, the movable mold 12 constituting the thin mold 30 is moved and fixed in the direction of the fixed mold 11 (upward in the present invention). At this time, the movable mold 12 is pressed against the fixed mold 11 with a force of 800 kN, and the molds may be clamped by a clamp, but in the present invention, a hydraulic press is used in consideration of workability. A load is applied. After the mold clamping, a vacuum pump (not shown) in the forced exhaust part 32 is operated, and detailed description is made in the molding part 14 in the thin molding die 30 from the gas discharge path 19 through the air vent 17 described later. Reduce pressure to 10 kPa in 5 seconds.

  Moreover, the injection molding part 31 deaerates the air held in the polycarbonate which is the main component of the resin constituting the lower case 1. Next, the resin is heated to a temperature of about 300 ° C. with a heater or the like, and sent to the thin mold 30 at a speed of about 2000 mm / sec while applying a pressure of about 300 MPa to the resin.

  The high-temperature molten resin sent out passes through the runner 21 divided into two directions inside the fixed mold 11 of the thin-walled mold 30 and is formed between the fixed mold 11 and the movable mold 12. Into 14. At this time, the gas remaining in the thin mold 30 and the gas generated from the resin are chased by the high-temperature molten resin, and the rib molding part provided in the insert 13 in the movable mold 12 18, the gas passes through a gas discharge path 19 having a slight gap on the surface where the inserts 13 are in contact with each other, and is exhausted to the air vent 17.

  The gas discharge path 19, which is a slight gap, is provided at the final filling position of the high-temperature molten resin, and the high-temperature molten resin itself that is injected and filled cannot pass through, but passes only the gas, A slight gap may be set so that the melted resin does not flow from the inside of the thin mold 30 to the outside. In the present invention, the gap is set to 0.01 to 0.1 mm.

  In addition, the air vent 17 is connected to the forced exhaust unit 32, and when the high temperature molten resin is filled, the gas remaining in the space portion that replaces the high temperature molten resin or the gas generated from the resin is quickly and thinly formed. It is discharged from the molding die 30. Furthermore, the cross-sectional area of the gas discharge part 19 provided along the surface of the nest connected to the rib forming part 18 of the nest 13 provided in the movable mold 12 and the cross-sectional area of the air vent 17 provided in the movable mold 12 By providing a large difference, an atmospheric pressure difference is instantaneously generated, and the exhaust gas flow rate is increased more than the resin filling speed, thereby efficiently discharging the gas.

  Here, when the gas is not collected due to the thin-walled molding die 30, trouble is caused, and the gas is obstructed so that the molten resin at a high temperature cannot be completely filled up to the details of the molding part 14, which is a resin molded product. The shape of the storage case 1 of the secondary battery pack becomes an irregular shape, and a defective lower case 1 having a chipped part or a dropped part is formed.

  Further, when a nest is generated by bubbles in the filled resin, it is difficult to ensure strength, which leads to deterioration of productivity and quality. Particularly in the case of resin molding with an injection speed of 1000 mm / second or more, the present invention in which the gas is discharged at a higher speed than the speed at which the resin is filled and is quickly discharged out of the thin mold 30 can provide a great effect. it can.

  The time required for the high temperature molten resin to reach the rib forming portion 18 in the details of the forming portion 14 is only 0.1 second, and then is held for 30 seconds, inside the thin mold 30. The resin is cooled by cooling to about 90 ° C., which is a temperature at which a certain high-temperature molten resin is solidified.

  A cooling pipe 15 is provided inside the insert 13 and is connected to the cooling unit 20 to keep the thin mold 30 at a constant temperature. The cooling unit 20 uses water, oil, or the like, and circulates between the inserts 13. In the present invention, the cooling unit 20 has a temperature of about 90 in order to stabilize the temperature of the thin-wall molding die 30 below the solidification temperature at which the resin solidifies. The hot melted resin at about 300 ° C. is cooled by keeping the temperature of the thin mold 30 constant by circulating hot water at 0 ° C.

  Thereafter, the operation of the forced exhaust part 32 is stopped, the movable mold 12 is moved away from the fixed mold 11, the fixed mold 11 and the movable mold 12 are opened, and the push pin ( The lower case 1 having the rib portion 2 at the center of the bottom surface of the storage container is taken out.

  Hereinafter, description will be made with reference to the drawings of a storage case for a secondary battery pack in an embodiment of the present invention. In addition, the embodiment mainly describes the lower case, and can be implemented in the upper case. The combination of the upper and lower cases is used as a storage case for the secondary battery pack.

  As shown in FIG. 2, the movable mold 12 is moved, and the fixed mold 11 and the movable mold 12 are clamped with a force of 800 kN by a hydraulic press. Next, the vacuum pump in the forced exhaust part 32 connected to the thin molding die 30 is operated to reduce the pressure in the thin molding die 30 to 10 kPa in 0.5 seconds. Here, the shape of the rib forming portion 18 of the insert 13 included in the movable mold 12 of the thin-walled mold 30 is a network having isotropic properties.

  Further, the resin mainly composed of polycarbonate is warmed to about 300 degrees in the injection molding section 31, and a high-temperature molten resin is injected at a pressure of 300 MPa at a speed of 2000 mm / sec. After being injected for 1 second, the mold clamping is held for 30 seconds, and the cooling unit 20 connected to the thin-walled mold 30 is cooled by the thin-walled mold 30 that is always kept at a mold temperature of about 90 ° C. The lower case 1, which is a storage case for a secondary battery pack in which a high-temperature molten resin is hardened, is separated from the fixed mold 11 and the movable mold 12 and taken out from the thin mold 30 with an extrusion pin.

Further, as shown in FIG. 2, the gas discharge path 19 provided in the movable mold 12 is provided with a cross-sectional area of 1.8 mm ² and a cross-sectional area of the air vent 17 of 30 mm ^2. A pressure difference is generated to increase the flow velocity during suction, accelerate the transition to a vacuum state, and efficiently discharge air from the molding die from the rib molding unit 18.

  As shown in FIG. 1, an isotropic mesh-like rib portion 2 is formed at the center of the bottom surface of the lower case 1, and the outer dimension of the lower case 1 is a square having a length of 40 mm and a width of 40 mm. The height is 3 mm. Moreover, the thickness of the side plate of the lower case 1 is 0.8 mm, and the thickness of the bottom surface is 0.25 mm. Furthermore, the mesh-like rib portion 2 having isotropicity at the center of the bottom surface occupies an area of 20 mm length and 20 mm width, the height of each rib is 0.02 mm, the width is 0.02 mm, and the pitch between the ribs Is 1 mm. The lower case 1 in which a mesh-like rib portion 2 having isotropicity was formed at the center of the bottom surface of the lower case 1 was taken as Example 1.

  As shown in FIG. 4, the lower case 1 having the same specification as that of the first embodiment and the lower case 1 having the isotropic spiral rib portion 2 formed at the center of the bottom surface of the lower case 1 is formed in the second embodiment. It was.

(Comparative Example 1)
For comparison with the embodiment of the present invention, as shown in FIG. 6, the lower case 50 is a storage case for a secondary battery pack having the same specifications as in the first embodiment. The sample whose part was not molded was designated as Comparative Example 1.

(Comparative Example 2)
As shown in FIG. 9, after the movable mold 313 and the fixed mold 312 of the resin mold 315 are clamped with a force of 800 kN, the mold is heated to about 300 ° C. from an injection molding section (not shown), and 10 kPa. A high-temperature molten resin to which pressure is applied is injected into a molding part 314 in the mold through a filling path 311 in the movable mold 313 of the resin molding mold 315. Here, the forming portion 314 is made of a SUS sintered material having a minute hollow portion provided as an air vent.

After the injection, the mold clamping for 30 seconds was held to produce a lower case 50 as shown in FIG. The lower case 50 is a lower case 50 in which minute cavities are transferred to the entire surface of the lower case 50 and minute protrusions such as a rough surface are formed.

  In order to compare the strength of the lower case, the filling degree of the resin, and the gas discharge performance using the lower case 1 and 50 shown in the examples and comparative examples as described above, The results of the evaluation are shown in (Table 1).

  The strength of the lower case, which is the storage case for the secondary battery pack shown in Table 1, was measured by measuring the amount of deflection when the center of the bottom surface of the lower case was pressurized from the outside with a pressure of 0.1 MPa. Did. Moreover, the thickness of the bottom surface of the lower case was measured and compared as the thickness measurement of the bottom surface. Further, as the resin filling amount ratio, the ratio of the weight of the resin to be filled to 0.9 g and the weight of the lower case, which is a storage case for the produced secondary battery pack, is shown.

  Further, as shown in FIG. 5, the supply pipe 56 connected to the compressed air supply unit (not shown) is connected to the thin mold 30 as shown in FIG. The measuring container 58 and the air vent of the thin mold 30 are connected by a connection pipe 57. Next, 300 cc of compressed air with a pressure of 0.05 MPa is fed from a compressed air supply unit (not shown) into a thin mold 30 that has been clamped at 800 kN through a supply pipe 56, and from an air vent of the mold 30. The ratio of the amount of air taken into the thin mold 30 from the compressed air supply unit and the amount of air exhausted from the thin mold 30 by taking the discharged air into the air metering container 58 of the water tank 55 containing water Expressed. The compared data is shown in (Table 1).

  As is clear from Table 1, in Examples 1 and 2 of the present invention, compared to Comparative Examples 1 and 2, the strength capable of suppressing the deflection of the central portion of the bottom surface of the lower case when pressurized under the same conditions. It can be seen that the bottom case is excellent in thinning the bottom. Further, the warp of the storage case of the secondary battery pack can be greatly improved by the isotropic rib portion provided at the center of the bottom surface of the lower case which is the storage case of the secondary battery pack of Examples 1 and 2. it is conceivable that.

  In addition, the thickness of the bottom surface of the lower case of Examples 1 and 2 is also stably produced. In the case of Comparative Example 1, the thickness of the bottom surface of the lower case is stable, but the structure has no rib portion. Therefore, it is inferior to Examples 1 and 2 in terms of strength. Further, the thickness of the bottom surface of the lower case is thicker than that of Comparative Example 2, and the strength surface is better than that of Comparative Example 1 due to the thickness, but the strength surface is also inferior compared with Examples 1 and 2. I understand.

  Here, as the cause of the increase in the thickness of the bottom surface of Comparative Example 2, only the porous portion formed as a minute cavity provided as an air vent of the molding die is compressed by the pressure at the time of resin filling, and compressed by the external pressure. When deformation occurs, it is considered that bending occurs in the molding portion of the molding die, leading to an increase in the thickness of the bottom surface of the lower case.

Regarding the cause of the compressive deformation of the porous hollow portion provided as an air vent, the base material is SUS sintered material, and the material of the molding part is hard as in Examples 1 and 2. It can be considered that the hardness is weaker than that of a quenching material such as SKD material, and the minute cavities further reduce the compressive strength.

  In addition, comparing the resin filling ratio, Examples 1 and 2 can be said to be a high-density lower case in which the resin is well packed, and there is no gas nest inside the resin, and also in terms of strength It can be said that it is strong. On the other hand, in Comparative Examples 1 and 2, the ratio of filling the supplied resin with respect to the weight is low and the lower case has a low density, and it is considered that nests are generated inside the resin. These are considered to be because the gas in the molding die was not sufficiently discharged at the time of resin filling, and the gas was obstructing at the time of filling.

  With regard to the amount of gas discharged, Examples 1 and 2 discharge a large amount of air, which indicates that the gas discharging property is good, and the rib forming part considering isotropic is efficient. It can be seen that air was discharged from the molding die. Moreover, it can be said that Example 2 which is a shaping die for forming a mesh-shaped rib portion is better in gas discharge than Example 1 which is a forming die for forming a spiral rib portion.

  Judging from the comparison results of Examples 1 and 2 and Comparative Examples 1 and 2 above, by providing a rib portion at the center of the bottom surface of the lower case, sufficient strength can be secured, In the case of excellent gas discharge performance, the load when filling the mold with high-temperature molten resin is reduced, thereby reducing the gas generated by shear heat inside the high-temperature molten resin. It becomes possible.

  In addition, in order to obtain the effect of exhausting gas, conventionally, it is necessary to enlarge the gas exhausting part, but the exhaust speed of the exhaust gas due to the pressure difference utilizing the cross-sectional area difference between the gas exhausting part of the present invention and the air vent is reduced. Lower case of secondary battery pack storage case can be efficiently exhausted without filling high temperature melted resin into the gas exhaust groove and holes due to the increase, without forming unnecessary burrs Can be stably filled.

  The lower case of the present invention has sufficient strength of the bottom surface of the lower case, and as a result, the bottom surface of the secondary battery is realized by realizing thinning of the bottom surface and stored in the storage case of the secondary battery pack to which the upper and lower cases are joined. It turns out that it is excellent in realizing high capacity. In addition, even in the lower case manufacturing equipment, by reducing the gas pool inside the gas molding die, reducing defects called gas burning on the surface of thin resin molded products that occur when resin molding is performed with ultra-high-speed injection In addition, it is considered that the warpage of the thin resin molded product can be greatly improved by reducing the internal stress accumulated in the thin resin molded product and the temperature of the thin resin molded product.

  According to the present invention, the rib portion is provided at the center of the bottom surface of the storage case of the secondary battery pack, so that sufficient strength can be obtained even when a load is applied despite the thin wall when storing the secondary battery. It is useful for constituting a high-capacity secondary battery pack using this.

  In addition, by discharging the gas at the rib forming part that forms the rib part at the center of the bottom surface of the storage case of the secondary battery pack, the gas discharge is good and the resin filling rate and the resin molded product It becomes possible to produce a resin molded product with improved production stability and quality.

The perspective view of the lower case in one embodiment of the present invention Schematic cross-sectional view of a thin-walled mold in an embodiment of the present invention The schematic diagram of the movable metal mold | die in one embodiment of this invention The perspective view of the lower case in Example 2 of the present invention Schematic diagram of exhaust gas measurement experiment in the same example The perspective view of the lower case which is a storage case of the pack for secondary batteries in the comparative example 1 The perspective view of the lower case which is a storage case of the pack for secondary batteries in the comparative example 2 The perspective view of the storage case of the pack for secondary batteries in a prior art example Schematic diagram of resin mold in conventional example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lower case 2 Rib part 11 Fixed mold 12 Movable mold 13 Nesting 14 Molding part 15 Cooling pipe 17 Air vent 18 Rib molding part 19 Gas discharge part 20 Cooling part 21 Runway 30 Thin-wall molding die 31 Injection molding part 32 Forced exhaust 50 Lower case 55 Water tank 56 Supply pipe 57 Connection pipe 58 Air volume measuring container

Claims (10)

A storage case for a secondary battery pack comprising at least a first case for storing a secondary battery and a second case joined to the first case,
The first case has a bottom surface and a shape having a side surface around the bottom surface, and a rib portion is provided in an inner direction of the center portion of the bottom surface for housing the secondary battery. Pack storage case.   2. The storage case for a secondary battery pack according to claim 1, wherein the rib portion has an isotropic mesh shape or spiral shape.   The storage case for a secondary battery pack according to claim 1 or 2, wherein the height of the convex part of the concave-convex shape of the rib section is greater than or equal to the thickness of the bottom surface. . An apparatus for manufacturing a storage case for a secondary battery pack according to any one of claims 1 to 3,
A thin mold formed of a fixed mold and a movable movable mold provided so as to be opposed to and separated from the fixed mold, and connected to an injection molding portion for resin molding, and the interior of the movable mold An apparatus for producing a storage case for a secondary battery pack, comprising: a nest having a rib forming part; a cooling part connected to the nest; and a gas exhaust means.   The apparatus for manufacturing a storage case for a secondary battery pack according to claim 4, wherein gas is discharged from the rib forming portion of the insert.   The apparatus for manufacturing a storage case for a secondary battery pack according to claim 4, wherein a gas exhaust means is connected to the rib forming portion of the insert.   The apparatus for manufacturing a storage case for a rechargeable battery pack according to claim 4, wherein the rib forming portion of the insert is formed in an isotropic mesh shape or spiral shape.   6. The apparatus for manufacturing a storage case for a secondary battery pack according to claim 5, wherein the rib forming portion of the insert is configured such that gas can be discharged from all directions when the resin is filled.   5. The gas exhausting means is configured by connecting an air vent and a forced exhausting part through a gas exhausting path provided along a surface of the nesting connected to the rib forming part of the nesting. The manufacturing apparatus of the storage case of the pack for secondary batteries as described.   The gas exhaust means has a cross-sectional area of an air vent provided in a movable mold larger than a cross-sectional area of a gas discharge part provided along a surface of the nesting connected to a rib forming part of the nesting. The manufacturing apparatus of the storage case of the pack for secondary batteries of Claim 4.

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