JP2014089822A - Battery module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the degradation of a battery cell and a reduction in cell performance by improving cooling efficiency.SOLUTION: Each battery cell 30 held by a holding tray 40 is cooled by a cooling air flowing beneath the holding tray 40. The cooling air flows along side wall parts 45, 45 in a long side 43y direction of an opening in each accommodation recess 42. In the accommodation recess 42, the battery cells 30 are accommodated with their side face along a long side 31y on a top face 31a facing the side wall parts 45, 45. Also, the cooling air flows beneath the accommodation recess 42, so each battery cell 30 are cooled from the underside as well.

Description

  The present invention relates to a battery module including a plurality of battery cells.

In recent years, lithium ion secondary batteries and the like have been used as battery systems for mobile bodies such as electric vehicles, and power storage systems in natural energy power generation facilities using wind power and sunlight.
Such a secondary battery forms a battery module by connecting a plurality of battery cells in series or in parallel.

  When each battery cell constituting the battery module is charged or discharged from the battery cell, the battery cell itself generates heat due to the internal resistance of the battery cell. This heat generation becomes larger as the performance of the battery cell increases. However, when the temperature of the battery cell rises to a high temperature, the battery cell may be deteriorated and the battery performance may be lowered.

Therefore, Patent Document 1 discloses a configuration including a cooling flow path for flowing cooling air around a battery group housed in an outer container.
In the technique described in Patent Document 1, as shown in FIG. 8, a plurality of battery cells 2 constituting the battery group 1 are arranged in the case 3 at intervals. Each battery cell 2 is fitted in a fitting groove 4 having a lower end 2 a formed in the bottom surface 3 a of the case 3. The upper end portion 2b of each battery cell 2 is hermetically penetrated and held in a through hole 5a formed in a partition wall 5 provided on the upper portion of the battery cell 2. And by flowing cooling air toward the exhaust port 8 formed in the other end side from the air supply port 7 formed in the one end side of the cooling flow path 6 between the bottom face 3a of the case 3 and the partition wall 5, Each battery cell 2 is cooled.

JP 2010-192209 A (FIG. 1)

  However, in the configuration described in Patent Document 1, the rectangular parallelepiped battery cells 2 constituting the battery group 1 face each other in the state in which the side surfaces 2c in the long side direction of the rectangle in a plan view face each other. Are arranged along a direction orthogonal to the. With respect to the battery group 1, the cooling air from the air supply port 7 toward the exhaust port 8 hardly flows between the battery cells 2 and 2 facing each other. For this reason, there exists a problem that the side surface 2c of the battery cell 2 which has a big area in the cooling flow path 6 cannot be cooled effectively, and cooling efficiency is low.

Moreover, since the lower end 2a of each battery cell 2 of the battery group 1 is covered by the bottom surface 3a of the case 3, and the partition wall 5 is also provided on the upper end 2b, the lower end 2a and the upper end of each battery cell 2 are provided. In the vicinity of 2b, the cooling air hardly flows. In addition, since the air supply port 7 and the exhaust port 8 are formed in the middle portion in the vertical direction of the battery group 1, the upper end portion 2b and the lower end portion of the battery cell 2 with respect to the middle portion 2d in the vertical direction of each battery cell 2. In the vicinity of 2a, the tendency that the flow of the cooling air is poor is more remarkable.
As a result, in each battery cell 2, the upper end 2b and the lower end 2a are less likely to be cooled with respect to the middle portion 2d in the vertical direction, and the temperature distribution varies greatly depending on the location.

  This invention is made | formed in view of such a situation, Comprising: It aims at providing the battery module which improves cooling efficiency and prevents deterioration and a performance fall of a battery cell.

In order to solve the above problems, the battery module of the present invention employs the following means.
The battery module of the present invention includes a battery cell having an electrode on the upper surface, a holding plate integrally formed with a housing recess for housing the battery cell with at least the upper surface exposed upward, and an opening on the upper side. A lower case forming the cooling medium flow path between the holding plate and the lower surface of the holding plate, and cooling in which the cooling medium is introduced into the flow path. A medium introduction section and a cooling medium discharge section that discharges the cooling medium from the flow path to the outside of the lower case.
The battery module is provided with a holding plate in which the battery module is housed in the housing recess so as to close the opening of the lower case, and a cooling medium flow path is provided between the holding plate and the lower case. Cooled through.
Since the housing recess is integrally formed with the holding plate, it is formed to project downward from the holding plate. By housing the battery module in the housing recess, almost the entire surface excluding the upper surface of the battery module can be cooled.
Further, the holding plate can separate the cooling medium flow path on the lower case side below from the upper side where the electrode of the battery cell is exposed. Furthermore, this makes it possible to flow not only a gas such as air but also a liquid such as water as a cooling medium in the flow path of the cooling medium below the holding plate.

The housing recess is integrally formed with a bottom plate portion that supports the bottom surface of the battery cell and a side wall portion that faces the side surface of the battery cell.
Cooling by the cooling medium through the holding plate can be efficiently performed by having the bottom plate and the side wall along the bottom and side surfaces of the battery cell.
Furthermore, the battery cell has a rectangular shape in plan view, a first side surface along two long sides facing each other on the upper surface, and a second side surface along two short sides facing each other on the upper surface, The side wall portion facing the first side surface of the battery cell in the housing recess is provided along the flow direction of the cooling medium in the flow path. That is, since the cooling refrigerant flows along the first side surface having a larger area than the second side surface, the battery cell can be cooled more efficiently.

Here, it is preferable that the accommodating recess is formed so as to accommodate a plurality of the battery cells along the flow direction of the cooling medium.
Here, the housing recess may be formed long and continuously in the flow direction of the cooling medium, and a plurality of battery cells may be housed side by side along the flow direction in one housing recess. Further, a plurality of housing recesses may be formed in the flow direction of the cooling medium, and the battery cell may be housed in each housing recess.

  It is preferable that a gap is formed between the bottom plate portion of the housing recess and the bottom surface of the lower case. Thereby, the battery cell accommodated in the accommodation recessed part can be cooled also from a bottom face.

Moreover, you may make it further provide the upper cover which covers the upper direction of the said holding | maintenance plate.
With this upper cover, the electrode of the battery cell can be covered, and dustproofness can be improved.

Further, the accommodation recess may be provided with a plurality of rows in a direction orthogonal to the flow direction of the cooling medium, and a connecting member that connects the accommodation recesses adjacent to each other may be provided.
Since the connecting member is positioned in the flow of the cooling medium, the connecting member is also cooled by the cooling medium, and can contribute to cooling of the battery cell.

Furthermore, a sheet material made of a material having a larger linear expansion coefficient than the material forming the holding plate may be sandwiched between the housing recess and the battery cell.
In the sheet material, when the holding plate expands due to the heat generation of the battery cell, the amount of expansion of the sheet material is larger than that of the holding plate, so that the adhesion between the holding recess of the holding plate and the battery cell can be improved.

  According to the present invention, the battery module is housed in the housing recess formed integrally with the holding plate, and the battery module can be cooled via the holding plate by the cooling medium flowing under the holding plate. Thereby, it becomes possible to improve a cooling efficiency and to prevent deterioration of a battery cell and a performance fall.

It is a perspective developed view which shows the structure of the battery module which concerns on 1st Embodiment of this invention. It is a figure which shows the battery module which concerns on 1st Embodiment of this invention, and is sectional drawing in the cross section orthogonal to the longitudinal direction of an accommodation recessed part. It is a perspective view which shows the battery cell of the battery module of this invention. It is a perspective view which shows the holding plate of the battery module of this invention. It is a figure which shows the battery module which concerns on 2nd Embodiment of this invention, (a) is sectional drawing of a battery module, (b) is a perspective sectional view which shows the spacer provided in the holding plate. It is a perspective sectional view showing other examples of the spacer of the present invention. It is sectional drawing of the battery module which concerns on 3rd Embodiment of this invention. It is sectional drawing which shows the structure of the battery module as a prior art example of this invention.

Hereinafter, an embodiment of a battery module according to the present invention will be described with reference to the drawings.
[First Embodiment]
The first embodiment of the present invention will be described below.
As shown in FIGS. 1 and 2, the battery module 10 </ b> A includes a lower case 20, a holding tray 40 that holds a plurality of battery cells 30, and an upper case 50.

  The lower case 20 is integrally provided with a bottom plate 21 that is rectangular in plan view, a side wall 22 that rises upward from the four sides around the bottom plate 21, and a flange portion 23 that projects from the upper end of the side wall 22 to the outer peripheral side, It has a container shape that opens upward.

  In the rectangular bottom plate 21, an air inlet (cooling medium introducing portion) 24 is formed on one of the side walls 22A and 22A along the short sides 21x and 21x facing each other, and an air outlet (cooling medium discharge) is formed on the other side. Part) 25 is formed. The air intake 24 or the air discharge port 25 is provided with a blower such as a fan (not shown). By operating the blower, the bottom plate 21 of the lower case 20 and the side walls 22 and 22 of the surrounding four sides from the air intake 24. The cooling air is taken into the space S surrounded by... And discharged from the air discharge port 25. Thereby, in the space S, the flow F of the cooling air in the direction along the long side 21 y of the bottom plate 21 is formed from the air intake port 24 toward the air discharge port 25.

As shown in FIG. 3, the battery cell 30 includes a rectangular parallelepiped cell case 31 in which a battery main body (not shown) is accommodated, and terminals 32 and 33 provided on the upper surface 31 a of the cell case 31. Here, the cell case 31 has a rectangular shape in plan view, and of the four side surfaces (second side surfaces) 34, 34 and the side surfaces (first side surfaces) 35, 35 orthogonal to the upper surface 31a, the long side 31y of the upper surface 31a. The side surfaces 35 and 35 along the side have a larger area than the side surfaces 34 and 34 along the short side 31x of the upper surface 31a.
Further, the terminals 32 and 33 are arranged along the direction along the long side 31 y of the upper surface 31 a of the cell case 31.

  As shown in FIGS. 1, 2, and 4, the holding tray 40 is made of metal, and includes a flat plate portion 41 and an accommodation recess 42 that is formed in the plate portion 41 and accommodates the battery cell 30. In preparation.

  The plate portion 41 has a rectangular shape with an outer peripheral portion 41 s overlapping the flange portion 23 of the lower case 20.

The housing recess 42 has an opening 43 that is rectangular in plan view and continues along the long side 41 y of the plate portion 41. The length of the long side 43y of the opening 43 is set to be slightly larger than an integral multiple of the long side 31y of the cell case 31 of the battery cell 30, and the length of the short side 43x of the opening 43 is The dimension is set slightly larger than the short side 31x of the case 31.
The accommodating recess 42 extends from the four sides (short side 43x, long side 43y) of the opening 43 to the side wall portions 44, 44, 45, 45 extending perpendicularly to the surface 41a of the plate portion 41 and on one side of the plate portion 41. And a bottomed cylindrical shape including a rectangular bottom plate portion 42 b orthogonal to the side wall portions 44, 44, 45, 45. The side wall portions 44, 44, 45, 45 have a height equivalent to the height of the cell case 31 of the battery cell 30. The height of the side wall portions 44, 44, 45, 45 is set to be smaller than the height of the side wall 22 (the height of the space S) of the lower case 20.

In such an accommodation recess 42, a predetermined number (for example, four) of battery cells 30 are arranged in a series in which the long side 31 y of the cell case 31 is aligned in the same direction as the long side 43 y of the opening 43. Is housed in.
The holding tray 40 is provided with a plurality of such accommodating recesses 42 (four in the example of FIG. 1) in parallel with each other at intervals.

As shown in FIGS. 1 and 2, the upper case 50 includes a rectangular top plate portion 51, a peripheral wall portion 52 that extends from the four sides of the top plate portion 51 to one side of the top plate portion 51, and a tip of the peripheral wall portion 52. And a flange portion 53 projecting outward from the portion to the outer peripheral side.
The flange portion 53 is formed to face the outer peripheral portion 41 s of the plate portion 41 when the upper case 50 faces the holding tray 40.

In such a battery module 10 </ b> A, the holding tray 40 is set so that the outer peripheral portion 41 s of the plate portion 41 is placed on the flange portion 23 of the lower case 20. In this state, each storage recess 42 of the holding tray 40 is stored in the space S of the lower case 20. At this time, as shown in FIG. 1, the lower case 20 is formed so that a gap is formed between the bottom plate portion 42 b of the housing recess 42 and the bottom plate 21 of the lower case 20 so as to face each other with a certain distance. The depth of is set.
A predetermined number of battery cells 30 are accommodated in the plurality of accommodating recesses 42 of the holding tray 40. The predetermined number of battery cells 30 are connected in series or in parallel between the plurality of battery cells 30 by connecting the terminals 32 and 33 with a connection plate made of a conductive material (not shown).
Then, the upper case 50 is placed on the lower case 20 and the holding tray 40 with the flange 53 facing the outer peripheral portion 41 s of the plate portion 41 of the holding tray 40. Then, the flange portion 23 of the lower case 20, the outer peripheral portion 41s of the plate portion 41 of the holding tray 40, and the flange portion 53 of the upper case 50 are fastened by bolts or clamp fittings not shown. At this time, between the flange portion 23 of the lower case 20, the outer peripheral portion 41s of the plate portion 41 of the holding tray 40, and the flange portion 53 of the upper case 50, a sealing member made of a rubber-based material or the like is provided to ensure sealing performance. Is preferably sandwiched appropriately.

Then, as shown in FIG. 2, in the battery module 10 </ b> A, the plurality of battery cells 30 held by the holding tray 40 are accommodated in the box 100 formed by the lower case 20 and the upper case 50.
Further, the bottom plate portion 42 b of each receiving recess 42 protruding downward from the plate portion 41 of the holding tray 40 faces the space S of the lower case 20. As a result, the cooling air flowing between the holding tray 40 and the lower case 20 hits the bottom plate portion 42 b of each housing recess 42, and each battery cell 30 is cooled via the housing recess 42.

As described above, each battery cell 30 held by the holding tray 40 can be cooled by the cooling air flowing below the holding tray 40. At this time, the cooling air flows along the side wall portions 45 and 45 in the direction of the long side 43 y of the opening 43 in each housing recess 42. The battery cell 30 is housed in the housing recess 42 with the side surfaces 35, 35 along the long side 31 y of the upper surface 31 a facing the side wall portions 45, 45. Thereby, each battery cell 30 cools the side surfaces 35 and 35 having a large area among the four side surfaces 34, 34, 35 and 35.
In addition, since the cooling air flows through the gap below the bottom plate portion 42 b of the housing recess 42, the bottom surface 36 of each battery cell 30 is also cooled.
Therefore, each battery cell 30 can be efficiently cooled over almost the entire surface other than the upper surface 31a of the cell case 31, and the temperature distribution can be made uniform, and performance deterioration due to temperature rise can be suppressed.

  Each battery cell 30 is housed in a holding tray 40 in which a plate portion 41 and a housing recess 42 are integrally formed. The holding tray 40 is connected to the lower case 20 and the upper case 50 so that the outer peripheral portion of the plate portion 41 is provided. Since it is sandwiched and held, the space S2 between the upper case 50 and the holding tray 40 can be isolated from the outside air and the cooling air flowing in the lower case 20. Thereby, dust protection around the terminals 32 and 33 of each battery cell 30 can be achieved.

  Further, the holding tray 40 separates the space S in which the cooling air below the holding tray 40 flows from the space S2 on the terminal 32, 33 side above the holding tray 40, thereby converting the cooling air into the space S. Instead, a liquid can be introduced as a cooling medium, and water cooling is also possible.

  In addition, since the entire cell case 31 is housed in the housing recess 42, each battery cell 30 can be stably held instead of being fixed only partially, It is also possible to improve vibration characteristics.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. In the second embodiment described below, the same components as those in the first embodiment will be denoted by the same reference numerals in the drawings, and the description thereof will be omitted. The description will focus on differences from the first embodiment. Do.
As shown in FIGS. 5A and 5B, the battery module 10 </ b> B of this embodiment includes a spacer (a connecting member) that connects the housing recesses 42, 42 between the housing recesses 42, 42 adjacent to each other in the holding tray 40. ) 46 is provided.

  The spacer 46 is made of metal and is formed by a belt-like plate continuously extending in the longitudinal direction of the housing recess 42, and both widthwise end portions 46 a and 46 a are side walls in the direction of the long side 43 y of the housing recesses 42 and 42 on both sides. It is connected to the parts 45, 45 by welding, adhesion or the like. In the present embodiment, a plurality of spacers 46 (three in the example of FIG. 5) are provided between the housing recesses 42 and 42 with a space in the height direction of the side wall 45.

By configuring the battery module 10B using the holding tray 40 having such a spacer 46, the battery cell 30 accommodated in the accommodation recess 42 expands in the thickness direction (short side 31x direction). Can be restrained. Thereby, the performance deterioration of the battery cell 30 can be prevented.
Further, the cooling air flowing under the holding tray 40 comes into contact with the spacer 46, whereby the cooling performance of the battery cell 30 can be improved.
Further, by connecting the housing recesses 42 and 42 adjacent to each other with the spacer 46, the entire holding tray 40 can be reinforced and vibration resistance can be further improved.

In the second embodiment, the spacer 46 is a belt-like plate, but the length thereof may be the same as the longitudinal direction of the accommodating recess 42, or the shorter spacer 46 may be accommodated in the accommodating recess. A plurality of sheets may be provided along the longitudinal direction of 42. For example, as shown in FIG. 6, for example, a columnar or prismatic spacer (connecting member) 47 having an axis in the direction connecting the receiving recesses 42 adjacent to each other may be provided. Furthermore, instead of the columnar or prismatic spacer 47, between the housing recesses 42 adjacent to each other, from the side wall 45 of one housing recess 42 toward the side wall 45 of the other housing recess 42, For example, a plurality of hemispherical convex portions whose cross-sectional area gradually decreases may be provided.
These cylindrical and prismatic spacers 47 and convex portions may be arranged in a matrix form in a plane along the side wall portion 45 of the accommodating concave portion 42, for example, in a staggered manner (see FIG. 6). May be.

[Third Embodiment]
Next, a third embodiment of the present invention will be described. In the third embodiment described below, the same components as those in the first embodiment will be denoted by the same reference numerals in the drawings, and the description thereof will be omitted. The description will focus on differences from the first embodiment. Do.
As shown in FIG. 7, the battery module 10 </ b> C of the present embodiment is housed in the inner circumferential surface 42 i of the housing recess 42 and the housing recess 42 in the same holding tray 40 as that shown in the first embodiment. A heat transfer sheet (sheet material) 49 is interposed between the battery cells 30.

  The heat transfer sheet 49 is formed of a sheet material having high thermal conductivity and a linear expansion coefficient larger than that of the metal forming the holding tray 40, for example, filled with a high thermal conductivity filler.

  In the battery module 10 </ b> C provided with such a heat transfer sheet 49, when the heat transfer sheet 49 and the housing recess 42 rise in temperature due to the heat generated by the battery cells 30, the expansion amount of the heat transfer sheet 49 is greater than that of the holding tray 40. It becomes larger than the amount of expansion. Then, the heat transfer sheet 49 expands greatly between the battery cell 30 and the housing recess 42, and the battery cell 30 and the housing recess 42 are in close contact with each other via the heat transfer sheet 49. Thereby, the thermal resistance between the battery cell 30 and the accommodation recessed part 42 can be reduced, the heat of the battery cell 30 can be efficiently propagated to the heat transfer sheet 49 and the holding tray 40, and the cooling effect can be enhanced.

The configurations shown in the first to third embodiments can be combined as appropriate.
Further, by accommodating the battery cell 30 in the housing recess 42 with the side surfaces 35, 35 along the long side 31 y of the upper surface 31 a facing the side wall portions 45, 45, the plurality of battery cells 30 are so-called longitudinal. However, the present invention is not limited to this, and a plurality of battery cells 30 may be stacked in the short direction and accommodated in the accommodating recess 42. That is, the battery cell 30 accommodates the accommodating recess 42 with the side surfaces 34, 34 along the long side 31 x of the upper surface 31 a facing the side wall portions 45, 45. Even in such a configuration, a sufficiently high cooling efficiency can be obtained as compared with the conventional case by using the holding plate 40 provided with the housing recess 42 for housing the plurality of battery cells 30 as in the above.
In addition, although the plurality of battery cells 30 are accommodated in rows in the accommodating recesses 42, a plurality of accommodating recesses 42 for accommodating the battery cells 30 one by one may be formed along one direction. Also in this case, each accommodation recessed part 42 arrange | positions the long side direction according to the direction of the flow F of cooling air.

10A, 10B, 10C Battery module 20 Lower case 21 Bottom plate 21x Short side 21y Long side 22 Side wall 22A Side wall 23 Flange part 24 Air intake (cooling medium introduction part)
25 Air outlet (cooling medium outlet)
30 battery cell 31 cell case 31a upper surface 31x short side 31y long side 32, 33 terminal 34 side surface (second side surface)
35 Side (first side)
36 bottom 40 holding tray 41 plate 41a surface 41s outer periphery 41y long side 42 accommodating recess 42b bottom plate 42i inner peripheral surface 43 opening 43x short side 43y long side 44, 45 side wall 46 spacer (connecting member)
47 Spacer (Connecting member)
49 Heat transfer sheet (sheet material)
50 Upper case 51 Top plate part 52 Peripheral wall part 53 Flange part 100 Box S, S2 space

Claims (8)

A battery cell with electrodes on the top surface;
A holding plate in which a housing recess for housing the battery cell is integrally formed with at least the upper surface exposed upward;
A lower case that opens upward, is mounted with the holding plate so as to close the opening, and forms a flow path of a cooling medium between the lower surface of the holding plate;
A cooling medium introduction section for introducing the cooling medium into the flow path;
A cooling medium discharge unit for discharging the cooling medium from the flow path to the outside of the lower case;
A battery module comprising:   2. The battery module according to claim 1, wherein the housing recess includes a bottom plate portion that supports a bottom surface of the battery cell and a side wall portion that faces the side surface of the battery cell. The battery cell has a rectangular top view and a first side surface along two long sides facing each other on the upper surface and a second side surface along two long sides facing each other on the upper surface. And
3. The battery module according to claim 2, wherein the side wall portion facing the first side surface of the battery cell in the housing recess is provided along a flow direction of the cooling medium in the flow path. .   The battery module according to claim 3, wherein the housing recess is formed so as to be capable of housing a plurality of the battery cells along a flow direction of the cooling medium.   5. The battery module according to claim 2, wherein a gap is formed between the bottom plate portion of the housing recess and a bottom surface of the lower case.   The battery module according to claim 1, further comprising an upper cover that covers an upper portion of the holding plate. The accommodating recess is provided with a plurality of rows in a direction orthogonal to the flow direction of the cooling medium,
The battery module according to claim 1, further comprising a connecting member that connects the housing recesses adjacent to each other.   The sheet material made of a material having a larger linear expansion coefficient than the material forming the holding plate is sandwiched between the housing recess and the battery cell. The battery module according to item.

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