JP6898972B2 - Battery case manufacturing method and battery case - Google Patents

Description

The present invention relates to a method for manufacturing a battery case and a battery case.

In electric vehicles and hybrid vehicles, a plurality of battery cells (hereinafter, simply referred to as "cells" in the present specification) composed of secondary batteries such as lithium ion batteries are housed in a battery case as a power source for a drive motor. The battery pack is installed.

A conventional battery pack is configured by modularizing a cell group in which a plurality of cells are stacked by restraining them with a restraining member such as a bind bar, and accommodating the modularized cell group in a battery case. However, when a plurality of cells are modularized and accommodated in the battery case, the plurality of cells cannot be efficiently accommodated, and the cell mounting density with respect to the battery case is small. Therefore, it is desired that a plurality of cells are directly housed in the battery case without being modularized.

Japanese Unexamined Patent Publication No. 2014-164850

In order to allow a plurality of cells to be directly accommodated in the battery case, the battery case is composed of a bottom wall portion and a box-shaped container having a standing wall portion erected from the bottom wall portion and opening upward, and inside the battery case. There is a method of accommodating the cell directly from above. Such a battery case can be manufactured inexpensively and easily by making it a cast product (die-cast product) cast from a metal such as aluminum.

However, in the battery case made of a cast product, it is necessary to provide a draft in the standing wall portion in consideration of mold removal. As a result, since the inner surface of the standing wall portion becomes an inclined surface, the cell housed inside the standing wall portion cannot be brought into close contact with the inner surface of the standing wall portion, which is useless due to the draft between the cell and the standing wall portion. Space is created. For this reason, not only the case size is unnecessarily increased, but also the cell cannot be brought into close contact with the vertical wall portion and fixed in the battery case. In order to eliminate such wasted space, the inner surface of the standing wall after casting is shaved to form a vertical surface, or additional parts for forming a vertical surface are added to the inner surface of the standing wall after casting. It is necessary to provide it, and there is a problem of soaring processing cost and weight increase due to additional parts.

An object of the present invention is to provide a method for manufacturing a battery case and a battery case which can be cast so that the inner surface of the standing wall portion becomes a vertical surface and can increase the cell mounting density.

(1) The method for manufacturing a battery case according to the present invention includes a bottom wall portion (for example, a bottom wall portion 11 described later) and a standing wall portion (for example, a standing wall portion 12, a side wall portion 121) erected from the bottom wall portion. A battery made of a cast product having an end wall portion 122, an intermediate wall portion 123, and a central end wall portion 124) and in which a plurality of cells (for example, cell 100 described later) are housed inside a box-shaped container that opens upward. A method for manufacturing a case (for example, a battery case 10 described later), wherein an outer surface (for example, an outer surface described later) is located in a mold (for example, a mold 50 described later) at a position corresponding to the inside of the standing wall portion of the battery case. The first core (21a, 22a) is a plane perpendicular to the bottom wall portion, and the inner surface (for example, the inner surfaces 21b, 22b described later) has a draft having a draft inclined with respect to the bottom wall portion. For example, casting is performed by arranging the first core 20) described later.

According to the above (1), it is not necessary to scrape the inner surface of the standing wall portion after casting or to provide an additional part for forming a vertical surface on the inner surface of the standing wall portion after casting, and the inner surface of the standing wall portion is bottomed. A battery case can be cast in which the surface is perpendicular to the wall and the inner surfaces of the bottom wall and the standing wall intersect vertically. For this reason, the cell can be brought into close contact with both the bottom wall portion and the standing wall portion, no wasted space is formed in the battery case, and a battery case capable of increasing the cell mounting density can be easily manufactured. can do.

(2) In the method for manufacturing a battery case according to (1), the vertical wall portion or the bottom wall portion has a temperature control medium flow path (for example, a temperature control medium flow path 16 described later) recessed from the outside. A second core (for example, a second core 30 described later) is further arranged at a position corresponding to the temperature control medium flow path of the vertical wall portion or the bottom wall portion in the mold. , The temperature control medium flow path may be cast.

According to the above (2), the temperature control medium flow path can be formed at the same time when the battery case is cast. Therefore, it is not necessary to retrofit the temperature control medium flow path or post-process it to make a recess, it is possible to suppress an increase in the number of parts, and it is possible to eliminate complicated processing work. Since the temperature control medium flow path can be formed with a simple structure recessed from the outer surface of the vertical wall portion, high sealing performance can be ensured when the outer surface side of the temperature control medium flow path is covered with the flow path lid.

(3) In the method for manufacturing a battery case according to (2), the vertical wall portion includes a side wall portion (for example, a side wall portion 121 described later) arranged along the stacking direction of the cells, and the side wall portion includes the side wall portion. The second core may be arranged at a position corresponding to the temperature control medium flow path of the side wall portion in the mold having the temperature control medium flow path.

According to the above (3), it is possible to manufacture a battery case in which the cell can be efficiently temperature-controlled by the temperature control medium. Normally, the temperature of the cell near the electrode terminal tends to be high, and the cell is arranged in the battery case with the surface having the electrode terminal facing upward. Therefore, when cooling the cell, the temperature is higher than that of the bottom wall of the battery case. It is possible to efficiently cool the cell by providing the temperature control medium flow path on the side wall portion.

(4) The battery case according to the present invention has a bottom wall portion (for example, a bottom wall portion 11 described later) and a vertical wall portion (for example, a vertical wall portion 12, a side wall portion 121, and an end wall portion) erected from the bottom wall portion. A battery case (for example, a battery case made of a cast product) in which a plurality of cells (for example, cell 100 described later) are housed inside a box-shaped container having 122, an intermediate wall portion 123, and a central end wall portion 124) and opening upward. For example, in the battery case 10) described later, the bottom wall portion and the inner surface of the standing wall portion (for example, the inner surfaces 121a, 122a, 124a described later) intersect vertically without being machined.

According to the above (4), it is possible to provide a battery case in which the cell can be brought into close contact with both wall surfaces of the bottom wall portion and the standing wall portion, and the cell mounting density can be increased.

According to the present invention, it is possible to provide a method for manufacturing a battery case and a battery case which can be cast so that the inner surface of the standing wall portion becomes a vertical surface and can increase the cell mounting density.

It is a perspective view which shows the battery case which concerns on one Embodiment of this invention. It is a perspective view which shows the core which is arranged in the mold when casting the battery case which concerns on one Embodiment of this invention. It is a vertical sectional view of the first core. It is a vertical cross-sectional view which cut the mold in which the core was arranged along the direction orthogonal to the stacking direction of a cell. It is a vertical cross-sectional view which cut the mold in which the core was arranged along the stacking direction of a cell. It is a perspective view which shows the battery pack which concerns on one Embodiment of this invention. It is a vertical cross-sectional view which cut the battery pack which concerns on one Embodiment of this invention along the direction orthogonal to the stacking direction of a cell. It is a vertical cross-sectional view which cut the battery pack which concerns on one Embodiment of this invention along the stacking direction of a cell.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
As shown in FIG. 1, the battery case 10 has a bottom wall portion 11 having a rectangular shape in a plan view and a standing wall portion 12 erected from the upper surface of the bottom wall portion 11, and is a box-shaped container that opens upward. Consists of. The battery case 10 is formed long in the X direction in the drawing. In the direction shown in the figure, the X direction indicates the length direction of the battery case 10. The Y direction indicates the width direction of the battery case 10. The Z direction indicates the height direction of the battery case 10.

The vertical wall portion 12 has side wall portions 121, 121, end wall portions 122, 122, intermediate wall portions 123, 123, and central end wall portions 124, 124. The side wall portions 121 and 121 are arranged at both ends in the width direction of the battery case 10 and extend along the length direction of the battery case 10. The end wall portions 122 and 122 are arranged at both ends of the battery case 10 in the length direction. The heights of the side wall portions 121, 121 and the end wall portions 122, 122 from the bottom wall portion 11 are the same. The side wall portions 121, 121 and the end wall portions 122, 122 form an outer wall of the battery case 10 that surrounds the four circumferences of the bottom wall portion 11.

The intermediate wall portions 123 and 123 extend from the end wall portions 122 and 122 toward the central portion of the battery case 10 along the length direction at the central portion in the width direction of the battery case 10. In the central portion of the battery case 10, the ends of the intermediate wall portions 123 and 123 are separated from each other with a predetermined distance. The central end wall portions 124, 124 are arranged in parallel with the end wall portions 122, 122 in contact with the end portions of the intermediate wall portions 123, 123 arranged in the central portion of the battery case 10, respectively, and have a width of the battery case 10. It extends in the direction.

As a result, inside the battery case 10 surrounded by the side wall portions 121, 121 and the end wall portions 122, 122, the four cell accommodating portions 13 partitioned by the intermediate wall portion 123 and the central end wall portion 124, and the central end A functional component accommodating portion 14 between the wall portions 124 and 124 is formed. The functional component accommodating portion 14 is provided with a plurality of reinforcing ribs 15 extending so as to connect the central end wall portions 124, 124 to each other. The heights of the intermediate wall portions 123, 123 and the central end wall portions 124, 124 from the bottom wall portion 11 are the same, but the heights of the side wall portions 121, 121 and the end wall portions 122, 122 from the bottom wall portion 11 are the same. Low compared to height.

The side wall portions 121 and 121 have temperature control medium flow paths 16 and 16 recessed from the outer surface side, respectively. By supplying the temperature control medium (cooling water or warming water) from the temperature control medium supply unit (not shown) to the temperature control medium flow paths 16 and 16, the temperature of the cell (not shown) housed in the cell storage unit 13 is supplied. Make a key. The temperature control medium flow paths 16 and 16 of the side wall portions 121 and 121 communicate with each other via a communication flow path 17 recessed in the lower surface of the bottom wall portion 11 corresponding to the functional component accommodating portion 14.

The battery case 10 is a cast product (die-cast product) made of aluminum or an aluminum alloy, and is obtained by integrally casting the bottom wall portion 11 and the standing wall portion 12 using a mold. At this time, the reinforcing rib 15, the temperature control medium flow paths 16, 16 and the connecting flow path 17 are also integrally cast.

In the battery case 10 of the present embodiment, at least the inner surfaces of each vertical wall portion 12 and the bottom wall portion 11, specifically, each vertical wall portion 12 and the bottom wall portion 11 facing at least in each cell accommodating portion 13. The inner surfaces, more specifically, at least the inner surface 121a of the side wall portion 121, the inner surface 122a of the end wall portion 122, the inner surface 124a of the central end wall portion 124, and the bottom wall portion 11 are not machined after casting. It intersects vertically. In general, the mold is required to have a draft of a predetermined angle, so that vertically intersecting surfaces cannot be cast. Therefore, when the battery case 10 of the present embodiment is cast using the mold, the core described below is arranged in the mold.

As shown in FIG. 2, the cores used when casting the battery case 10 of the present embodiment are the first cores 20 and 20, the second cores 30 and 30, and the third core. 40 and.

The first core 20 is formed in a rectangular frame shape in a plan view, and at the time of casting, the inner surface 121a of the side wall portion 121 facing the two cell accommodating portions 13 and 13 juxtaposed in the Y direction with the intermediate wall portion 123 interposed therebetween. , 121a, a core for forming the inner surface 122a of the end wall portion 122 and the inner surface 124a of the central end wall portion 124 so as to intersect perpendicularly with the bottom wall portion 11. Specifically, the first core 20 is a pair of side wall corresponding portions 21 and 21 for forming the inner surfaces 121a and 121a of the side wall portion 121, respectively, and the inner surface 122a and the central end wall portion 124 of the end wall portion 122. It has a pair of end wall corresponding portions 22, 22 for forming the inner surface 124a, respectively.

As shown in FIG. 3, in the side wall portion corresponding portion 21 and the end wall portion corresponding portion 22 of the first core 20, the inner surface 121a of the side wall portion 121 to be cast, the inner surface 122a of the end wall portion 122, and the central end wall portion. The outer surfaces 21a and 22a facing the inner surface 124a of the 124 are flat surfaces extending straight in parallel with the Z direction so as to be perpendicular to the bottom wall portion 11 to be cast. On the other hand, in the side wall portion corresponding portion 21 and the end wall portion corresponding portion 22 of the first core 20, the inner surface 121a of the side wall portion 121 to be cast, the inner surface 122a of the end wall portion 122, and the inner surface 124a of the central end wall portion 124. On the other hand, the inner surfaces 21b and 22b arranged on opposite sides are inclined surfaces having a draft inclined at a predetermined angle with respect to the bottom wall portion 11. Notches 221,221 corresponding to the intermediate wall portion 123 are formed in the central portion in the width direction of the end wall portion corresponding portions 22 and 22, respectively.

The second core 30 is a core for forming a recess serving as a temperature control medium flow path 16 in the side wall portion 121 at the time of casting, and is formed in the shape of a long rectangular plate extending along the side wall portion 121. ing.

The third core 40 is a core for forming a recess serving as a connecting flow path 17 in the bottom wall portion 11 at the time of casting, and has a rectangular plate shape extending over a pair of second cores 30 and 30. Is formed in.

The material of the first core 20, the second core 30, and the third core 40 is not particularly limited, and a core made of a material generally used as a core can be used. It is desirable to use sand or salt cores from the viewpoint of disintegrating the cores after die cutting so that they can be easily removed from the casting.

Next, a method of casting the battery case 10 using the first core 20, the second core 30, and the third core 40 will be described with reference to FIGS. 4 and 5.
As shown in FIGS. 4 and 5, the battery case 10 is formed by injecting molten aluminum or an aluminum alloy into a cavity 53 formed by a mold 50 composed of a molded upper mold 51 and a lower mold 52. Manufactured.

The mold 50 of the present embodiment is configured such that the upper mold 51 is a movable type, the lower mold 52 is a fixed type, and the upper mold 51 moves up and down with respect to the lower mold 52 in the Z direction. The side surface 51a of the upper die 51 is an inclined surface having a predetermined draft. Then, the first core 20, the second core 30, and the third core 40 are shown in the cavity 53 formed in the mold 50 when the upper mold 51 and the lower mold 52 are molded. Each is placed using a non-molding tool or the like.

Specifically, the first core 20 is arranged in the mold 50 at a position corresponding to the inside of each of the side wall portion 121, the end wall portion 122, and the central end wall portion 124 of the battery case 10. Since the inner surface 21b of the side wall portion corresponding portion 21 of the first core 20 and the inner surface 22b of the end wall portion corresponding portion 22 and the side surface 51a of the upper die 51 are inclined surfaces having a draft, the upper die 51 When the lower mold 52 and the lower mold 52 are molded, they come into close contact with each other.

The second core 30 is arranged in the mold 50 at a position corresponding to the temperature control medium flow path 16 provided on the side wall portion 121 of the battery case 10. The third core 40 is arranged in the mold 50 at a position corresponding to the communication flow path 17 provided in the bottom wall portion 11 of the battery case 10.

As a result, between the upper mold 51 and the lower mold 52, the bottom wall portion forming cavity portion 531 corresponding to the bottom wall portion 11, the side wall portion forming cavity portion 532 corresponding to the side wall portion 121, and the end wall portion 122 Cavity having at least an end wall forming cavity 533 corresponding to the above, an intermediate wall forming cavity 534 corresponding to the intermediate wall 123, and a central end wall forming cavity 535 corresponding to the central end wall 124. A 53 is formed, and casting is performed by injecting molten metal into the cavity 53.

When the mold 50 is opened after the molten metal has cooled and solidified, the upper mold 51 smoothly separates from the interface between the side surface 51a having a draft and the inner surfaces 21b and 22b of the first core 20. After taking out the cast product from the lower mold 52, the first core 20, the second core 30, and the third core 40 are removed to obtain the battery case 10 having the structure shown in FIG.

According to the method for manufacturing the battery case 10 of the present embodiment, the temperature control medium flow paths 16 and 16 and the communication flow paths 17 are formed at the same time as the battery case 10 is cast. Therefore, it is not necessary to retrofit these flow paths 16 and 17 or post-process them to make a recess, and it is possible to suppress an increase in the number of parts and eliminate complicated processing work.

The inner surfaces 121a, 122a, 124a of the side wall portion 121, the end wall portion 122, and the central end wall portion 124 of the obtained battery case 10 are formed by the outer surfaces 21a, 22a of the first core 20 which is a vertical surface. Therefore, it is a vertical surface with respect to the bottom wall portion 11. That is, according to this manufacturing method, in order to scrape the inner surfaces 121a, 122a, 124a of the side wall portion 121, the end wall portion 122, and the central end wall portion 124 after casting, or to form a vertical surface. Battery case in which the inner surfaces 121a, 122a, 124a are perpendicular to the bottom wall portion 11, and the bottom wall portion 11 and the inner surfaces 121a, 122a, 124a intersect vertically. 10 can be cast.

In the battery case 10 of the present embodiment, both side surfaces of the intermediate wall portion 123, each side surface of the central end wall portion 124 facing the functional component accommodating portion 14, and each outer surface of the side wall portion 121 and the end wall portion 122 are In relation to the cell 100, which will be described later, the surface does not necessarily have to be a surface perpendicular to the bottom wall portion 11, and therefore may be an inclined surface due to the draft of the mold 50.

As shown in FIG. 6, the flow path lids 18 and 18 are attached to the side wall portions 121 and 121 of the cast battery case 10 by means such as welding so as to close the outer surfaces of the temperature control medium flow paths 16 and 16. Be done. A flow path lid 19 is attached to the bottom wall portion 11 by means such as welding so as to close the outer surface (lower surface) of the connecting flow path 17. The temperature control medium flow path 16 and the communication flow path 17 have a simple structure in which the side wall portion 121 and the bottom wall portion 11 are recessed from the outer surfaces by using the second core 30 and the third core 40. Therefore, high sealing performance can be ensured when the outer surface side of the temperature control medium flow path 16 is covered with the flow path lids 18 and 19.

Each cell accommodating portion 13 of the battery case 10 accommodates a cell group in which a plurality of cells 100 are stacked in the X direction. The cell 100 is a rectangular parallelepiped square cell in which the electrode material is housed in a cell can made of aluminum or an aluminum alloy. As shown in FIGS. 7 and 8, a pair of positive and negative electrode terminals 101 and 101 project from the upper surface 100a of each cell 100. Each cell 100 is aligned in the upper surface 100a having the electrode terminals 101 and 101 so as to face upward of the battery case 10 and laminated in the X direction, and is housed in each cell housing unit 13. Insulating members (not shown) are arranged between adjacent cells 100 and 100.

As shown in FIG. 7, the elastic member 60 is arranged between each cell 100 and the intermediate wall portion 123. The elastic member 60 is elastic rubber or resin, a leaf spring, or the like, and is directed toward the inner surface 121a of the side wall portion 121 of the battery case 10 with respect to each cell 100 as shown by the white arrow in FIG. Gives a pressing force. Since the inner surface 121a of the side wall portion 121 is a surface perpendicular to the bottom wall portion 11 due to the use of the first core 20 at the time of casting, it is placed on the bottom wall portion 11 in the cell accommodating portion 13. Each of the cells 100 can be fixed in close contact with the inner surface 121a of the side wall portion 121 by the elastic member 60. Therefore, no wasted space is formed between the side wall portion 121 of the battery case 10 and the cell 100, the battery case 10 can be miniaturized accordingly, and the mounting density of the cell 100 with respect to the cell accommodating portion 13 is increased. be able to.

The cell group composed of the plurality of cells 100 is compressed along the stacking direction (X direction) before being accommodated in the cell accommodating portion 13, and is accommodated in the cell accommodating portion 13 in a compressed state. Therefore, the cell group after being housed in the cell housing portion 13 has the inner surface 122a and the center of the end wall portion 122 of the battery case 10 as shown by the white arrows in FIG. 8 due to the reaction force in the compressed state. It is pressed toward the inner surface 124a of the end wall portion 124. Since the inner surfaces 122a and 124a of the end wall portion 122 and the central end wall portion 124 are also perpendicular surfaces to the bottom wall portion 11 due to the use of the first core 20 at the time of casting, the cell accommodating portion 13 Each cell 100 placed on the inner bottom wall portion 11 can be closely fixed to the inner surfaces 122a and 124a of the end wall portion 122 and the central end wall portion 124, respectively. Therefore, no wasted space is formed between the end wall portion 122, the central end wall portion 124, and the cell 100 of the battery case 10, and the battery case 10 can be miniaturized accordingly, and the cell accommodating portion 13 can be used. The mounting density of the cell 100 can be increased.

The functional component accommodating portion 14 between the central end wall portions 124 and 124 accommodates functional components such as power distribution components (not shown). After the cell 100 is accommodated in each cell accommodating portion 13 of the battery case 10 and the functional component is accommodated in the functional component accommodating portion 14, a lid member (not shown) is attached to the upper surface of the battery case 10 by bolts or the like. As a result, the battery pack 1 is completed.

Since the battery case 10 of the present embodiment has the temperature control medium flow paths 16 and 16 in the side wall portions 121 and 121, the cell 100 is efficiently temperature-controlled by the temperature control medium in the temperature control medium flow paths 16 and 16. can do. Normally, in the cell 100, the temperature around the electrode terminals 101 and 101 tends to be high. As shown in FIG. 7, the cell 100 in the battery case 10 is arranged in the battery case 10 with the upper surface 100a having the electrode terminals 101 and 101 facing upward. Therefore, when the cell 100 is cooled, the battery is used. The cell 100 can be cooled more efficiently by providing the temperature control medium flow paths 16 and 16 in the side wall portions 121 and 121 closer to the electrode terminals 101 and 101 than in the bottom wall portion 11 of the case 10.

When it is necessary to make both side surfaces of the intermediate wall portion 123 and the inner surface facing the functional component accommodating portion 14 perpendicular to the bottom wall portion 11, both side surfaces of the intermediate wall portion 123 and the inner surface of the intermediate wall portion 123 in the mold 50. A core having the same configuration as that of the first core 20 may be arranged at a position corresponding to the inner surface facing the functional component accommodating portion 14 for casting.

The battery case 10 of the present embodiment has four cell accommodating portions 13 inside, but the number of cell accommodating portions 13 in the battery case 10 may be one or more. The intermediate wall portion 123 does not necessarily have to be provided in the battery case 10. Further, the functional component accommodating portion 14 does not necessarily have to be provided in the battery case 10. In this case, the central end wall portions 124 and 124 are not provided, and the cell 100 is accommodated between the pair of end wall portions 122 and 122 of the battery case 10.

10 Battery case 11 Bottom wall part 12 Standing wall part 121 Side wall part 122 End wall part 123 Intermediate wall part 124 Central end wall part 16 Temperature control medium flow path 20 First core 21a (1st core side wall corresponding part) Outer surface 21b (for the side wall of the first core) Inner surface 22a (for the end wall of the first core) Outer surface 22b (for the end wall of the first core) Inner surface 22b 30 Second core 50 Mold 100 cells

Claims (3)

A method for manufacturing a battery case made of a cast product having a bottom wall portion and a standing wall portion erected from the bottom wall portion, and a plurality of cells are housed inside a box-shaped container that opens upward.
At a position in the mold corresponding to the inside of the vertical wall portion of the battery case, the outer surface is perpendicular to the bottom wall portion and the inner surface has a draft inclined with respect to the bottom wall portion. A method of manufacturing a battery case in which the core of 1 is arranged and cast. The vertical wall portion or the bottom wall portion has a temperature control medium flow path recessed from the outer surface.
The first aspect of the present invention, wherein a second core is further arranged at a position corresponding to the temperature control medium flow path in the standing wall portion or the bottom wall portion in the mold to cast the temperature control medium flow path. The method of manufacturing the battery case described. The vertical wall portion includes a side wall portion arranged along the stacking direction of the cells, and the side wall portion has the temperature control medium flow path.
The method for manufacturing a battery case according to claim 2, wherein the second core is arranged at a position corresponding to the temperature control medium flow path of the side wall portion in the mold.

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