JP2012126058A - Battery tray - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the influence, for example, of the strength decline of a molding by a weld part in a battery tray formed by injection molding using a resin.SOLUTION: The battery tray 10 which is attached to an electric car, formed by injection molding using the resin, and loaded with a driving battery includes a bottom surface part 11e formed in the shape of a rectangle, a peripheral wall part 11 formed on the periphery of the bottom surface part 11e, and horizontal ribs 13F and 13R installed in the intermediate part in the longitudinal direction of the bottom surface part 11e to extend in the short hand direction. The weld part produced during injection molding is formed in a place excluding a high stress part among the bottom surface part 11e, the peripheral wall part 11, and the horizontal ribs 13F and 13R.

Description

  The present invention relates to a battery tray installed in an electric vehicle.

  A battery unit used in an electric vehicle includes a battery module and a battery case that houses the battery module. An example of the battery case includes a tray member (battery tray) that supports the battery module, a cover member that covers an upper portion of the tray member, and the like. For electric vehicles, how to increase the mileage is a major issue. Therefore, it is desired to mount a battery as large as possible.

  On the other hand, since the battery case is required to have insulation, a resin material is suitable as the material. However, since it is difficult to secure the rigidity and strength necessary to support a large battery in a resin battery case, a glass fiber reinforced resin (non-conductive fiber such as glass fiber) is included in the resin emphasis ( Fiber reinforced plastics (FRP) such as GFRP (Glass Fiber Reinforced Plastics) are used.

  Patent Document 1 discloses an example of a technique of providing a sheet metal insert member along the inner surface of the peripheral wall of the tray member of the battery case in order to reinforce the resin battery case.

JP 2010-153130 A

  By the way, when using resin for a battery case, when considering mass productivity of a tray member and a cover member, it is suitable to form these tray members and a cover member using injection molding, respectively. However, in a resin molded product by injection molding, a defective portion called a weld (hereinafter also referred to as a weld portion) is generated in the molded product due to the flow of resin in the mold during injection molding. This weld part occurs in the part where the resin reaches a certain direction from a different direction in the mold and collides with it, but this reduces the strength of the resin molded product and makes it as thick as possible. A tray member that tries to support a heavy battery while suppressing it is a big problem in securing strength.

  Also, when fiber reinforced resin is used for the battery case, it is preferable to mold these tray members and cover members using injection molding in consideration of mass productivity of the tray members and cover members. In this case, a thermoplastic resin is used as the resin, and so-called short fibers are used as the fibers added to the resin, and the resin is configured as a short fiber-reinforced thermoplastic (hereinafter referred to as SFRTP). It is common.

  In this SFRTP molded product, short fibers are oriented in the direction along the flow of resin during injection molding, and the directionality of the short fibers affects the properties of the molded product. In particular, in the case of a fiber reinforced resin, a weld portion is generated. In this weld portion, a sufficient reinforcing effect of short fibers cannot be obtained, and the dimensional accuracy is lowered, causing problems such as warpage. In this weld part, for example, in a thin plate-like body, short fibers are oriented in the thickness direction, and the orientation of the short fibers is often in a unique fiber orientation state. In this case, a tray member that supports a heavy battery while suppressing the thickness as much as possible is a greater problem in securing the strength.

  It is an object of the present invention to provide a battery tray which is a battery tray formed by injection molding using a resin, and which can suppress the influence such as a decrease in strength of a molded product due to a weld portion. Yes.

  In order to achieve the above object, the battery tray of the present invention is a battery tray mounted on an electric vehicle, formed by injection molding using a resin, and mounted with a driving battery, and is formed in a rectangular shape. An injection molding comprising: a bottom surface portion formed; a peripheral wall portion erected on an outer periphery of the bottom surface portion; and a lateral rib erected so as to extend in a short direction at a longitudinal intermediate portion of the bottom surface portion. In this case, a weld portion generated at the time is formed in a portion excluding a high stress portion among the bottom surface portion, the peripheral wall portion, and the lateral rib.

  At least two of the lateral ribs are formed in the middle portion in the longitudinal direction of the bottom surface portion, and each of the circumferential wall portions between the lateral circumferential wall portions extending in the short direction and the lateral ribs, respectively. A plurality of vertical ribs extending in the longitudinal direction are provided, and the battery is mounted in each region partitioned by the peripheral wall portion, the horizontal ribs, and the vertical ribs, and the high stress portion includes at least the horizontal ribs. It is preferable that

  At least two of the lateral ribs are formed in the middle portion in the longitudinal direction of the bottom surface portion, and each of the circumferential wall portions between the lateral circumferential wall portions extending in the short direction and the lateral ribs, respectively. A plurality of vertical ribs extending in the longitudinal direction are provided, and the battery is mounted in each region partitioned by the peripheral wall portion, the horizontal ribs, and the vertical ribs, and the high stress portion includes at least the horizontal ribs. It is preferable that it is a part except the center part in the extending direction in and a part of the bottom face part and the peripheral wall part close to the part.

It is preferable to form by injection molding using the resin from a gate position arranged at a position corresponding to the bottom surface portion between the plurality of vertical ribs.
It is preferable that reinforcing short fibers are added in the resin.

According to the battery tray of the present invention, since the weld portion generated during the injection molding is formed at a location excluding the high stress portion of the bottom surface portion, the peripheral wall portion, and the lateral rib, the rigidity and strength are reduced by the weld portion. Thus, the durability of the battery tray installed in the electric vehicle can be ensured.
Two horizontal ribs are formed in the middle portion in the longitudinal direction of the bottom surface portion, and a plurality of vertical ribs extending in the longitudinal direction are provided between each lateral circumferential wall portion and each lateral rib of the circumferential wall portion, whereby the rigidity of the tray is increased. It improves and it becomes easy to support a battery stably by arranging and mounting a battery (battery module) in each field divided by a peripheral wall part, a horizontal rib, and a vertical rib, respectively. And in this case, large stress is easily applied to the two lateral ribs, but since the weld portion is formed at a place other than these lateral ribs, a decrease in rigidity and strength of the lateral rib due to the weld portion is avoided, The durability of the battery tray installed in the electric vehicle can be ensured.

  In addition, among the two horizontal ribs, a large stress is easily applied to a portion other than the central portion in the extending direction of each horizontal rib, and a large stress is also easily applied to a part of the bottom surface portion and the peripheral wall portion adjacent to this portion. Since the weld part is formed at a place other than these parts, the influence of the rigidity and strength due to the weld part is avoided, and the durability of the battery tray installed in the electric vehicle can be ensured.

By placing the gate position at the time of injection molding at a location corresponding to the bottom surface portion between the plurality of vertical ribs, the weld portion is excluded from the lateral rib, the bottom surface portion adjacent to this, and a part of the peripheral wall portion. Can be formed.
In addition, the rigidity and strength of the battery tray can be improved by adding reinforcing short fibers in the resin. In the weld part, sufficient fiber reinforcement effect cannot be obtained, but because the weld part is formed in a place other than the place where rigidity and strength are most desired to be secured, the influence of rigidity and strength reduction due to the weld part is avoided. Thus, the durability of the battery tray installed in the electric vehicle can be ensured.

It is a top view explaining the structure of the battery tray concerning one Embodiment of this invention. It is a disassembled perspective view explaining the structure of the battery case concerning one Embodiment of this invention (The correspondence of each member is shown with a dashed-dotted line). It is a typical exploded perspective view explaining the mounting structure to the vehicle of the battery unit concerning one embodiment of the present invention. It is a figure for demonstrating the result of the CAE analysis regarding the characteristic of the load strength with respect to the location of the weld part concerning one Embodiment of this invention, (a)-(d) shows each analysis model of a battery tray. It is a perspective view. It is a figure for demonstrating the result of the CAE analysis regarding the characteristic of the load-bearing strength with respect to the location of the weld part concerning one Embodiment of this invention, and is based on each analysis model of the battery tray of (a)-(d) of FIG. It is a graph which shows the characteristic of load bearing strength. It is a perspective view of the battery tray for demonstrating the result of the computer analysis regarding the characteristic of the Mises stress of the battery tray concerning one Embodiment of this invention.

Hereinafter, embodiments will be described with reference to the drawings. Note that the embodiment described below is merely an example, and there is no intention to exclude various modifications and technical applications that are not explicitly described in the following embodiment.
[Battery case configuration]
First, the configuration of the battery case according to the present embodiment will be described with reference to FIGS. This battery case is applied to a battery unit used for an electric vehicle including a hybrid electric vehicle, that is, a battery unit including a driving battery for supplying electric power to a driving (driving) motor of the electric vehicle. . In the following description, it is assumed that the traveling direction of the electric vehicle is the front, the left and right are determined with reference to the front, the direction of gravity is the lower side, and vice versa. Further, a description will be given assuming that the side toward the center of the battery case is the inside and the opposite is the outside. Further, in the following description, the case where the battery tray constituting the battery case is in the lower side and the cover is located in the upper side is explained. However, when the battery case is used upside down, the upper and lower sides are reversed. .

  As shown in FIG. 3, the electric vehicle 1 includes a travel motor and a charging device (both not shown) disposed behind the vehicle body 2, a battery unit 6 disposed under the floor of the vehicle body 2, and the like. ing. Further, a floor panel 3 is provided above the battery unit 6, and a front seat 4F and a rear seat 4R are disposed above the floor panel 3, that is, in the vehicle interior.

  The floor panel 3 is formed of, for example, a sheet metal, and extends in the front-rear direction and the left-right direction of the vehicle body 2 and constitutes a floor portion of the vehicle body 2. The floor panel 3 is fixed to a predetermined position of a frame structure including a side member (not shown) constituting the vehicle body 2 by welding or the like. The battery unit 6 is arranged separately from the floor panel 3 below the floor panel 3, that is, below the floor that is outside the vehicle body. An under cover 5 is disposed below the battery unit 6 and is fixed to a frame structure or the like.

  As shown in FIG. 2, the battery unit 6 includes a plurality of driving batteries 8 (a part of which is illustrated in a two-dot chain line in FIG. 2), an electronic component (not shown), and the like inside a battery case 7. It is configured to accommodate. The battery case 7 includes a resin tray member (battery tray) 10 that supports a battery and the like, a resin cover member 20 that is superimposed on the tray member 10 and is coupled to and fixed to the tray member 10, and a tray member. 10 and a support member 30 that supports the tray member 10 from below.

  The tray member 10 and the cover member 20 are made of, for example, fiber reinforced resin (FRP) that is mixed with a fiber such as glass fiber as a reinforcing material to improve strength and rigidity and has electrical insulation. The support member 30 is made of a metal material (for example, a steel plate) having sufficient strength to support the load of the entire battery case 7. Moreover, the battery 8 accommodated in the battery case 7 is formed by connecting a plurality of battery cells formed of a secondary battery such as a lithium ion battery in series. Here, a battery module in which a plurality of battery cells or battery cells are connected to form a module (integrated) is collectively referred to as a battery 8.

  The tray member 10 has a front wall 11a, a rear wall 11b, a pair of left and right side walls 11c and 11d, and a bottom wall (bottom surface portion) 11e, and is formed into a box shape having an open upper surface side. The front wall 11a is positioned in front of the vehicle body 2 and the rear wall 11b is positioned in the rear of the vehicle body 2, and extends in the width direction (short direction) of the tray member 10 at both longitudinal ends of the tray member 10. The front wall 11a and the rear wall 11b are also referred to as a lateral peripheral wall portion. The side walls 11c and 11d extend in the front-rear direction, and the front wall 11a, the rear wall 11b, and the side walls 11c and 11d constitute a peripheral wall (peripheral wall portion) 11 of the tray member 10. Here, the front-rear direction is the longitudinal direction of the tray member 10 (or bottom wall 11e), and the left-right direction is the width direction (short direction) of the tray member 10 (or bottom wall 11e).

  In addition, the tray member 10 is provided with a plurality of partition walls (lateral ribs) 13F, 13C, and 13R that divide the tray member 10 in the middle in the longitudinal direction of the tray member 10. These partition walls 13F, 13C, and 13R all extend in the width direction of the tray member 10, partition the tray member 10 and enhance the rigidity of the tray member 10. The partition located in front of the vehicle body is the front partition 13F, the partition located in the rear of the vehicle is the rear partition 13R, and the partition located between the front partition 13F and the rear partition 13R is the middle partition 13C. By these partition walls 13F, 13C, and 13R, the longitudinal direction of the tray member 10 is partitioned into four sections. Note that the front partition 13F, the middle partition 13C, and the rear partition 13R are referred to as the partition 13 when not particularly distinguished.

  The tray member 10 has a plurality of front ribs (vertical ribs) 11f provided between the front wall 11a and the front partition wall 13F, and a plurality of rear ribs provided between the rear partition wall 13R and the rear wall 11b. Side ribs (vertical ribs) 11g are formed. The front rib 11f and the rear rib 11g are partition walls that divide the tray member 10 into a plurality of sections, and increase the rigidity of the tray member 10 to ensure the required rigidity. It is extended.

A tray-side flange portion 12 projects from the upper end of the peripheral wall 11 toward the outside along the horizontal direction at the peripheral edge portion of the upper end of the peripheral wall 11 of the tray member 10. The tray side flange portion 12 is continuously provided over the entire circumference of the tray member 10, and the tray member 10 and the cover member 20 are sealed by being joined to a cover side flange portion 22 described later.
Each part of the tray member 10 having such a shape is integrally formed by injection molding (injection molding). Injection molding is the most common resin molding method. A mold corresponding to the product shape consisting of a cavity (concave mold) and a core (convex mold) is prepared, and heated and melted in a molding machine. In this method, a resin raw material is injected into a mold at a high pressure. Here, a short glass fiber is added to the resin raw material to improve the rigidity and strength of the tray member 10.

  The support member 30 extends in a plurality of (here, four) width direction support portions 31 extending in the width direction of the tray member 10 and a direction orthogonal to the width direction support portion 31 (that is, the longitudinal direction of the tray member 10). A plurality of (in this case, two) longitudinal support portions 32 that connect the width direction support portions 31, and the width direction support portions 31 and the longitudinal direction support portions 32 form a so-called cross-beam shape. Has been. When the tray member 10 and the support member 30 are coupled to the width direction support portion 31, a plurality of penetrating through the width direction support portion 31 are provided at positions that overlap with a plurality of fastening portions 14, which will be described later, respectively provided on the tray member 10. Through-holes 36 are formed. Both end portions of the plurality of width direction support portions 31 and the front end portion of the longitudinal direction support portion 32 protrude outward from the peripheral wall of the tray member 10, and the protruding both end portions and front end portion are fixed to the frame structure, respectively. A fixed portion 33 is provided.

  The cover member 20 includes a cover main body 21 including a front raised portion 21a, a rear raised portion 21b, and a middle raised portion 21c, and a cover-side flange portion 22 provided on the peripheral edge of the cover main body 21, and a tray member. As in the case of 10, it is integrally formed by injection molding.

The tray member 10 and the cover member 20 include a plurality of bolts and nuts (not shown) while a gasket (not shown) is interposed between the tray side flange portion 12 and the cover side flange portion 22 and the gasket is compressed and deformed. The battery case 7 is hermetically sealed by joining the tray side flange portion 12 and the cover side flange portion 22 by the joining member. That is, the battery case 7 has a sealing property at its peripheral edge secured by the joining member and the gasket.
A plurality of fastening portions 14 are provided in the width direction of the tray member 10 on the front wall 11a, the rear wall 11b, and the partition wall 13 of the tray member 10. A fastening member (for example, a bolt and a nut) for fixing the battery 8 accommodated in the battery case 7 is fastened to the fastening portion 14.

[The battery tray weld]
Next, the position setting of the weld part of the tray member (battery tray) 10 will be described.

  Since the tray member 10 is molded by injection molding, a weld portion is generated in the molded tray member 10 due to the flow of resin in the mold during injection molding. This weld part occurs in the part where the resin reaches a certain direction from different directions in the mold and collides with it, so the shape of the mold and the gate that is the filling port when filling the mold with resin The location where the weld portion is generated can also be manipulated by the arrangement of.

The weld portion reduces the strength of the resin molded product and causes variations in strength. Therefore, it is possible to prevent the weld portion from being generated in a portion of the tray member 10 where stress is concentrated. This is important in the tray member 10 that attempts to support a heavy battery while suppressing it.
Therefore, a weld portion was set at a specific portion of the tray member 10 and analyzed by CAE (Computer Aided Engineering), and the influence of the weld occurrence portion on the load displacement characteristics of the tray member 10 was confirmed.

Specifically, a load CAE analysis was performed in which the weld portion was given the property of breaking at a strain of 15% of the normal portion, and the weld portion was set at each site shown in FIGS. 4 (a) to 4 (d). The load displacement characteristics of battery trays were compared.
4A is a reference model without a weld portion, FIG. 4B is a first comparative model in which the weld portion is on the entire peripheral wall (outer frame) 11, and FIG. 4C is a reference model with the weld portion on the peripheral wall. (Outer frame) 11 is a second comparative model in both the entire front wall 13F and both end portions of the front partition wall 13F. FIG. 4 (d) shows a weld portion below the entire peripheral wall (outer frame) 11 and both end portions of the front partition wall 13F. It is the 3rd comparative model which exists in both of some bottom walls 11e. Further, as shown by the arrow L in FIG. 4A, the load is applied from the right side with respect to the vicinity of the front partition wall 13F.

FIG. 5 shows the result of CAE analysis when a load L is applied. The relationship between the strain and stress generated in each model by applying the load L corresponds to the cylinder displacement corresponding to the strain and the stress. It is indicated by the load cell load. The yield point is where the load cell load suddenly decreases as the cylinder displacement increases, and the load resistance of each model is compared at this yield point.
As shown in FIG. 5, when compared with a reference model without a weld part (thick solid line), the first comparative model (thin solid line) with the weld part on the entire peripheral wall 11 has a load reduction of about 20 percent. In the second comparative model (broken line) in which the weld portion is located on both the entire peripheral wall 11 and both end portions of the front partition wall 13F, the load resistance is reduced by about 33%. The load resistance of the third comparative model (one-dot chain line) in which the weld is on both the entire peripheral wall 11 and part of the bottom wall 11e below the both ends of the front partition wall 13F is reduced by about 25%.

From this result, it can be presumed that the influence of the welds at both end portions of the front partition wall 13F is large in reducing the load resistance.
FIG. 6 shows Mises stress at the time of 20G load (equivalent to impact input) by computer analysis. In the figure, particularly high stress portions are marked and shown. The upper and lower 20G loads are added assuming a case where a load is applied from a wheel in a battery mounted state.

  Particularly high stress portions include both side portions P1 to P8 of the fastening portions 14 of the front partition wall 13F and the rear partition wall 13R except for the central portion in the width direction, and among them, both side portions P1 of the front partition wall 13F. , P4 has the highest stress value, the stress values of the side portions P2, P3 are higher than the middle of the front partition wall 13F, and then both side portions P5 to P8 of the rear partition wall 13R are higher. That is, since a large stress is applied to the front partition wall 13F and the rear partition wall 13R when an impact is input, it is considered that it is more effective to avoid the weld portion at a location where the stress value is particularly high.

Based on such analysis results, in the present embodiment, as shown in FIG. 1, both side portions 40 a to 40 d excluding the central portion in the width direction among the fastening portions 14 of the front partition wall 13 </ b> F and the rear partition wall 13 </ b> R. Gates 41a to 41e are arranged so as to form a weld portion at a place excluding the region (high stress portion).
The middle part of both side portions 40a covers the front partition 13F, and the middle part of both side portions 40b covers the rear partition 13R. Further, the region of both side portions 40c from the outside covers the front partition wall 13F, the side walls 11c, 11d and the bottom wall 11e, and the region of both side portions 40d from the outside covers the rear partition wall 13R, the side walls 11c, 11d and the bottom wall 11e. Is the target.

Gates 41a to 41e are arranged so that the weld portion is formed except for these portions. The gates 41a and 41b are between the front ribs 11f between the front wall 11a and the front partition wall 13F, and the gates 41c and 41d are between the rear ribs 11g between the rear wall 11b and the rear partition wall 13R. The gate 41e is an intermediate portion in the width direction between the front partition wall 13F and the rear partition wall 13R, and is provided along the formation site of the bottom wall 11e.
Here, as shown in FIG. 1, the gate 41 a and the gate 41 b are disposed at positions that are symmetrical with respect to the center line in the width direction of the battery tray 10. Similarly, the positions of the gate 41c and the gate 41d are also symmetrical. Further, with respect to the gate 41a and the gate 41b, the gate 41c and the gate 41d are provided at substantially target positions with respect to the center line in the front-rear direction of the battery tray 10. Further, the gate 41e is disposed at substantially the center position of the battery tray 10.
As described above, by arranging the gates 41a to 41e, the place where the weld is formed can be removed from the regions of the side portions 40a to 40d.

  That is, the weld part is formed by the collision part of the resin flowing from each gate, and the position of the collision part is determined by the injection timing, the injection speed, the flow rate, and the gate position. By simulating these, it is possible to determine an optimum gate position at which the weld portion can be removed from the regions of both side portions 40a to 40d. Here, the gates 41a to 41e are arranged as optimum gate positions from the trial results.

[effect]
The battery tray according to an embodiment of the present invention is configured as described above, and a weld portion generated at the time of injection molding is located at a portion excluding a high stress portion among the bottom wall 11e, the peripheral wall 11, and the partition walls 13F and 13R. Since it is formed, the influence of a decrease in rigidity and strength due to the weld portion is avoided, and the durability of the battery tray 10 provided in the electric vehicle can be ensured.

  In addition, by adding reinforcing short fibers in the resin, the rigidity and strength of the battery tray 10 can be improved, but in this case, a sufficient fiber reinforcing effect cannot be obtained in the weld portion. In this respect, since the weld portion is formed at a location excluding specific portions of the bottom wall 11e, the peripheral wall 11 and the partition walls 13F and 13R where it is desired to secure the most rigidity and strength, the influence of a decrease in stiffness and strength due to the weld portion is avoided. Thus, the durability of the battery tray installed in the electric vehicle can be ensured.

  In addition, by manipulating the position of the weld part by setting the gate position, the injection timing, injection speed, flow rate, etc. of the resin for injection molding are set to optimum values that take productivity into consideration, ensuring good productivity. However, it is possible to avoid the influence of a decrease in rigidity and strength due to the weld portion.

[Others]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  For example, in the above embodiment, the place where the weld portion is formed is set so as to be excluded from the regions of the side portions 40a to 40d focusing on the front partition wall 13F, the rear partition wall 13R, the side walls 11c and 11d, and the bottom wall 11e. However, the gate may be arranged so as to form the weld portion while avoiding this portion by paying attention only to the front barrier rib 13F and the rear barrier rib 13R or paying attention only to the front barrier rib 13F.

In addition, the operation of the position of the weld portion is not limited to the setting of the gate position, but any of resin injection timing, injection speed, flow rate, etc. may be used, or the gate position, injection timing, injection speed, flow rate may be used. The position of the weld portion may be manipulated by appropriately combining the above.
Further, application to a battery tray using a resin to which no reinforcing short fiber is added is also conceivable.

DESCRIPTION OF SYMBOLS 1 Electric vehicle 7 Battery case 8 Battery 9 Battery bracket (member)
10 Tray member (battery tray)
11 Perimeter wall (peripheral wall)
11e Bottom wall (bottom surface)
13, 13F, 13R, 13C Bulkhead (lateral rib)
40a-40d Both side parts (high stress part)
41a-41e gate

Claims (5)

A battery tray mounted on an electric vehicle, formed by injection molding using resin, and mounted with a battery for driving,
A bottom surface portion formed in a rectangular shape, a peripheral wall portion erected on the outer periphery of the bottom surface portion, and a lateral rib erected so as to extend in the short-side direction at a middle portion in the longitudinal direction of the bottom surface portion. Prepared,
The battery tray, wherein a weld portion generated during injection molding is formed at a location excluding a high stress portion among the bottom surface portion, the peripheral wall portion, and the lateral rib. At least two of the lateral ribs are formed in the longitudinal intermediate portion of the bottom surface,
A plurality of longitudinal ribs each extending in the longitudinal direction are provided between each lateral circumferential wall portion extending in the lateral direction of the circumferential wall portion and each lateral rib.
The battery is mounted in each region partitioned by the peripheral wall portion, the horizontal rib, and the vertical rib,
The battery tray according to claim 1, wherein the high stress portion is at least the lateral rib. At least two of the lateral ribs are formed in the longitudinal intermediate portion of the bottom surface,
A plurality of longitudinal ribs each extending in the longitudinal direction are provided between each lateral circumferential wall portion extending in the lateral direction of the circumferential wall portion and each lateral rib.
The battery is mounted in each region partitioned by the peripheral wall portion, the horizontal rib, and the vertical rib,
2. The battery tray according to claim 1, wherein the high-stress portion is at least a portion excluding a central portion in the extending direction of the lateral rib and a part of the bottom surface portion and the peripheral wall portion adjacent to the portion. . 4. The battery tray according to claim 2, wherein the battery tray is formed by injection molding using the resin from a gate position disposed at a position corresponding to the bottom surface portion between the plurality of vertical ribs. 5. The battery tray according to any one of claims 1 to 4, wherein a reinforcing short fiber is added in the resin.

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