JP7133348B2 - battery pack - Google Patents

Description

The present invention relates to a battery pack mounted on an electric vehicle or the like.

Electric vehicles and the like have conventionally been equipped with battery packs. A battery pack is configured by housing a battery module having a cell stack in which a plurality of cells are stacked in a case. Cells need to be cooled because they tend to deteriorate at high temperatures. For example, in Patent Document 1, a battery module is installed on a cooling plate into which a coolant is supplied.

JP 2013-122818 A

However, in Patent Literature 1, there is room for improvement in cooling efficiency because a gap is created between the cooling plate and the battery module. In order to increase the cooling efficiency, it is conceivable to install a spring that forcibly presses the cooling plate against the battery module or a heat transfer sheet to eliminate the gap. There is a problem of

The present invention provides a battery pack that can efficiently cool battery modules with a simple structure.

The present invention provides a battery module,
a cooling mechanism that cools the battery module,
The cooling mechanism is a bag-shaped body filled with a liquid medium and having flexibility,
The bag-shaped body is formed by welding the ends of at least two aluminum sheets together,
The welded end portion in which the ends of the at least two aluminum sheets are welded together is provided with a coolant inlet portion through which the liquid medium is introduced and a coolant outlet portion through which the liquid medium is discharged,
The battery module and the bag-like body are in indirect contact via a flexible insulating material.

According to the present invention, the flexible bag-shaped body filled with the liquid medium and the battery module are in direct contact with each other or indirectly via an insulating material. Therefore, the battery module can be efficiently cooled with a simple structure.

1 is a cross-sectional view of a battery pack according to a first embodiment of the invention; FIG. FIG. 2 is a perspective view of a battery module of the battery pack shown in FIG. 1 as seen obliquely from above; FIG. 2 is a perspective view of a battery module of the battery pack shown in FIG. 1 as seen obliquely from below; FIG. 2 is a front view schematically showing a battery module and a cooling mechanism of the battery pack shown in FIG. 1; FIG. 2 is a plan view schematically showing a battery module and a cooling mechanism of the battery pack shown in FIG. 1; FIG. 4 is a cross-sectional view of a battery pack according to a second embodiment of the invention;

Hereinafter, each embodiment of the battery pack of the present invention will be described based on the accompanying drawings.

[First embodiment]
<Battery pack>
As shown in FIG. 1, a battery pack 1 according to the first embodiment of the present invention includes a battery module 10, a cooling mechanism 70 that cools the battery module 10, and a battery case 80 that houses the battery module 10 and the cooling mechanism 70. , provided.

<Battery case>
The battery case 80 includes a case body 81 having a module accommodating portion 81a formed therein, and a case cover 82 that seals an opening 81b of the case body 81 . A cooling mechanism 70 is provided between the battery module 10 and the bottom portion 83 of the battery case 80 . Although two battery modules 10 are arranged inside the battery case 80 in this embodiment, the number of battery modules 10 may be one, or three or more.

<Battery module>
As shown in FIGS. 2 and 3, the battery module 10 is configured by stacking a plurality of cells 21 in the front-rear direction. A pair of end plates 30 arranged on the front and rear surfaces of the stack 20 , a side plate 50 connecting the pair of end plates 30 , and a bottom plate 60 arranged on the bottom surface of the cell stack 20 are provided. The side plate 50 includes a right side plate 50R arranged on the right surface of the cell stack 20 and a left side plate 50L arranged on the left surface of the cell stack 20. As shown in FIG.

In this specification and the like, the stacking direction of the cells 21 is defined as the front-rear direction, and the directions perpendicular to the stacking direction of the cells 21 are defined as the left-right direction and the up-down direction, for the sake of simplicity and clarity of explanation. It has nothing to do with the front-rear direction of the product in which the battery module 10 is mounted. That is, when the battery module 10 is mounted on a vehicle, the stacking direction of the cells 21 may be aligned with the front-rear direction of the vehicle, or may be the vertical direction or the horizontal direction of the vehicle, or may be inclined from these directions. It can be a direction. In the drawings, the front of the battery module 10 is indicated by Fr, the rear by Rr, the left by L, the right by R, the upper by U, and the lower by D. As shown in FIG.

(cell laminate)
The cell stack 20 is configured by alternately stacking a plurality of cells 21 and insulating members (not shown) in the front-rear direction. A pair of end plates 30 are arranged on the front and rear surfaces of the cell stack 20 , respectively, and a bottom plate 60 is arranged on the bottom surface of the cell stack 20 . A right side plate 50R and a left side plate 50L are arranged on the left side and the right side of the cell stack 20 in an insulated state with a slight gap therebetween.

It is known that the cells 21 expand due to temperature changes and aging deterioration. The cell 21 has a rectangular parallelepiped shape whose length in the vertical direction is longer than the length in the front-rear direction and the length in the horizontal direction is longer than the length in the vertical direction. Therefore, the area of the front surface and the rear surface of the cell 21 is much larger than the areas of the left surface, the right surface, the top surface and the bottom surface, and the front surface and the rear surface of the cell 21 tend to expand at the center in the horizontal direction and the center in the vertical direction.

(end plate)
The pair of end plates 30 respectively abut on the front and rear surfaces of the cell stack 20 and receive the load of the cell stack 20 in the cell stacking direction. The load in the cell stacking direction of the cell stack 20 is mainly due to the expansion of the cells 21 due to temperature changes and aging deterioration. Since the central portion in the vertical direction expands easily, a large load is input to the central portion in the horizontal direction and the central portion in the vertical direction of the end plate 30 .

The end plate 30 is formed using an aluminum extrusion material. Since the end plate 30 receives a large load from the cell stack 20 in the cell stacking direction, the inner surface that contacts the cell stack 20 is flat, while the outer surface that does not contact the cell stack 20 is flat. The surface has an outwardly bulging shape. A plurality of screw holes (not shown) to which bolts B1 for fastening the left side plate 50L and the right side plate 50R are attached are provided near the left and right ends of each end plate 30 .

(side plate)
The left side plate 50L and the right side plate 50R are formed by press-working a metal plate material. 30, a rear flange portion 52R extending from the rear end of the side plate body 51 along the rear surface of the rear end plate 30 in a direction toward each other, and a side plate body. an upper flange portion 53 extending from the upper end of the cell stack 20 along the upper surface of the cell stack 20 in a direction toward each other; a lower flange portion 54 extending from the lower end of the side plate main body 51 along the lower surface of the bottom plate 60 in a direction toward each other; Prepare.

The front flange portion 52F and the rear flange portion 52R are provided with a plurality of fastening portions 52a that are fastened to the front end plate 30 or the rear end plate 30 via bolts B1. The fastening portion 52a has a round hole through which the bolt B1 is inserted, and by screwing the bolt B1 inserted through the round hole into the screw hole of the front end plate 30 or the rear end plate 30, the front flange portion 52F is formed. And the rear flange portion 52R is fastened to the front end plate 30 or the rear end plate 30 . Thereby, the cell stack 20 and the pair of end plates 30 are held in the cell stacking direction by the front flange portion 52F and the rear flange portion 52R of the left side plate 50L and the right side plate 50R.

The upper flange portion 53 and the lower flange portion 54 sandwich the cell stack 20 and the bottom plate 60 from above and below at the left end and right end of the cell stack 20 . The upper flange portion 53 is composed of a plurality of elastic pieces 53a arranged in the front-rear direction, and the number and positions of the elastic pieces 53a correspond to the number and positions of the cells 21 stacked in the front-rear direction.

The lower flange portion 54 is provided with a plurality of fastening portions 54a that are fastened to the bottom plate 60 via bolts B2. Thereby, the left side plate 50L, the right side plate 50R, and the bottom plate 60 that constitute the side plate 50 are integrally connected.

The fastening portion 54a provided in the lower flange portion 54 of the right side plate 50R is a notch portion that opens leftward, and the fastening portion 54a provided in the lower flange portion 54 of the left side plate 50L is a notch portion that opens rightward. Department. As a result, the right side plate 50R and the left side plate 50L can be mounted from the left and right while the bolt B2 is temporarily fixed to the bottom plate 60. As shown in FIG.

(bottom plate)
The bottom plate 60 is formed using an extruded aluminum material, and includes a bottom plate body 61 extending along the lower surfaces of the cell stack 20 and the end plates 30, and protruding upward from both left and right ends of the bottom plate body 61, and It has a guide portion (not shown) extending in the front-rear direction, and a through hole 61f through which a bolt B2 fastened to the fastening portion 54a of the lower flange portion 54 penetrates. The bottom plate main body 61 has a rectangular shape in a plan view, and the length dimension in the front-rear direction is selected to be approximately equal to the distance between the front and rear ends of the front and rear end plates 30 .

<Cooling mechanism>
Returning to FIG. 1, the cooling mechanism 70 is composed of a bag-like body 71 filled with a liquid medium W and having flexibility. In this example, two battery modules 10 are arranged side by side on the bag-shaped body 71 (in a direction orthogonal to the stacking direction of the cells 21). The battery module 10 and the bag-like body 71 are in indirect contact with each other via an insulating material 72 having flexibility. The insulating material 72 electrically insulates the battery module 10 and the bag-like body 71 and is made of a material having good thermal conductivity.

As shown in FIG. 4, the bag-like body 71 is formed by welding the ends 73a of two aluminum sheets 73 together, and can be easily manufactured. As shown in FIG. 5, the welded end portion 74, in which the ends 73a of the two aluminum sheets 73 of the bag-like body 71 are welded together, has a refrigerant inlet portion 75i into which the liquid medium W is introduced and a liquid medium W inlet portion 75i. A refrigerant outlet portion 75o is provided through which the is discharged. As a result, the coolant inlet portion 75i and the coolant outlet portion 75o are formed without making holes in the aluminum sheet 73, so that the sealing performance of the bag-like body 71 is less likely to deteriorate.

Inside the bag-shaped body 71, a flow path 77 for the liquid medium W is formed by a plurality of welded portions 76 obtained by welding the facing sheet surfaces of the two aluminum sheets 73 together. By welding desired positions of the facing sheet surfaces of the two aluminum sheets 73, a wall composed of the welded portions 76 is provided inside the bag-like body 71, and a flow path 77 having a desired shape is easily formed. can do. In this example, the welded portions 76 extend from one end of the bag-shaped body 71 in the left-right direction to the vicinity of the other end, and the adjacent welded portions 76 extend from the other end in the left-right direction of the bag-shaped body 71 . It extends near one end, and by repeating this, a flow path 77 that meanders left and right is formed. The meandering flow path 77 for the liquid medium W realizes the cooling mechanism 70 with high cooling efficiency.

According to the battery pack 1 of the first embodiment configured as described above, the cooling mechanism 70 is composed of the bag-like body 71 filled with the liquid medium W and having flexibility. Since the battery module 10 is installed on top of the battery module 10 with the insulating material 72 interposed therebetween, the bag-like body 71 that is inflated by the pressure of the liquid medium W can be pressed against the lower surface of the battery module 10 and brought into close contact therewith. Thereby, the battery module 10 can be efficiently cooled with a simple structure without providing a spring or a heat transfer sheet. In addition, since the battery pack 1 can control the expansion of the bag-like body 71 by adjusting the pressure of the liquid medium W supplied to the bag-like body 71, the layout of the cooling mechanism 70 has a high degree of freedom.

[Second embodiment]
In the battery pack 2 of the second embodiment, the cooling mechanism 70 is arranged between the battery module 10 and the ceiling portion 84 of the battery case 80, as shown in FIG. A general water jacket can only be placed below the battery module 10 in the battery case 80, but the bag-like body 71 that constitutes the cooling mechanism 70 adjusts the pressure of the liquid medium W inside to prevent swelling. Since it can be controlled, it becomes possible to dispose the cooling mechanism 70 above the battery module 10 . By arranging the cooling mechanism 70 on the upper part of the battery module 10, the battery module 10 can be cooled from the upper part where heat tends to accumulate, so that the battery module 10 can be cooled more efficiently.

It should be noted that the present invention is not limited to the above-described embodiments, and can be modified, improved, etc. as appropriate. For example, in the above embodiment, the bag-like body 71 is formed using two aluminum sheets 73, but it may be formed using two or more aluminum sheets 73, and one aluminum sheet is folded to form an end. It may be formed by welding the parts together.

In addition, in the second embodiment, the bag-like body 71 constituting the cooling mechanism 70 is arranged between the battery module 10 and the ceiling portion 84 of the battery case 80. , between the side of the battery module 10 and the side of the battery case 80 . It is also possible to arrange the bag-like body 71 on the top and sides of the battery module 10 in the battery case 80 .

In the above embodiment, the battery module 10 and the bag-shaped body 71 are in indirect contact with each other through the insulating material 72. , the battery module 10 and the bag-like body 71 may be brought into direct contact with each other.

In addition, at least the following matters are described in this specification. In addition, although the parenthesis shows the components corresponding to the above-described embodiment, the present invention is not limited to this.

(1) a battery module (battery module 10);
A battery pack (battery packs 1 and 2) comprising a cooling mechanism (cooling mechanism 70) that cools the battery module,
The cooling mechanism is a bag-shaped body (bag-shaped body 71) filled with a liquid medium (liquid medium W) and having flexibility,
A battery pack in which the battery module and the bag-shaped body are in direct contact or in indirect contact via a flexible insulating material (insulating material 72).

According to (1), the inside is filled with a liquid medium, the cooling mechanism is configured by a flexible bag-shaped body, and the battery module and the bag-shaped body are directly connected or via a flexible insulating material. The indirect contact allows the bag-shaped body, which expands under the pressure of the liquid medium, to be pressed against the battery module and brought into close contact. As a result, the battery module can be efficiently cooled with a simple structure without providing a spring or a heat transfer sheet. In addition, since the pressure of the liquid medium can be used to control the expansion of the bag-shaped body, the layout of the cooling mechanism has a high degree of freedom.

(2) The battery pack according to (1),
The bag-shaped body is a battery pack formed by welding ends (ends 73a) of at least two aluminum sheets (aluminum sheets 73).

According to (2), the bag-shaped body can be easily manufactured.

(3) The battery pack according to (2),
At the end welded portion (end welded portion 74) where the ends of the at least two aluminum sheets are welded together, a refrigerant inlet portion (refrigerant inlet portion 75i) into which the liquid medium is introduced and the liquid medium is discharged. A battery pack provided with a coolant outlet (refrigerant outlet 75o).

According to (3), since the coolant inlet and coolant outlet are formed without making holes in the aluminum sheet, the sealing performance of the bag-shaped body is less likely to deteriorate.

(4) The battery pack according to (3),
The battery, wherein a flow path (flow path 77) for the liquid medium is formed inside the bag-shaped body by a welded portion (welded portion 76) in which the facing sheet surfaces of at least two aluminum sheets are welded together. pack.

According to (4), the flow path can be easily formed by welding the facing sheet surfaces of the two aluminum sheets at desired positions.

(5) The battery pack according to any one of (1) to (4),
The battery pack further comprises a battery case (battery case 80) that houses the battery module and the cooling mechanism,
The battery pack, wherein the cooling mechanism is arranged between a side portion of the battery module or an upper portion (ceiling portion 84) of the battery module and the battery case.

According to (5), a general water jacket can only be placed at the bottom of the battery module, but the bag-like body can control the swelling by adjusting the pressure of the liquid medium inside. It can be arranged between the top of the battery module and the battery case.

1, 2 Battery pack 10 Battery module 70 Cooling mechanism 71 Bag-shaped body 72 Insulating material 73 Aluminum sheet 73a Edge 74 Edge welding part 75i Refrigerant inlet part 75o Refrigerant outlet part 76 Welding part 77 Flow path 80 Battery case 84 Ceiling part ( upper part)
W liquid medium

Claims (3)

a battery module;
a cooling mechanism that cools the battery module,
The cooling mechanism is a bag-like body filled with a liquid medium and having flexibility,
The bag-shaped body is formed by welding the ends of at least two aluminum sheets together,
The welded end portion in which the ends of the at least two aluminum sheets are welded together is provided with a coolant inlet portion through which the liquid medium is introduced and a coolant outlet portion through which the liquid medium is discharged,
A battery pack in which the battery module and the bag-like body are in indirect contact via a flexible insulating material. The battery pack according to claim 1,
A battery pack, wherein a flow path for the liquid medium is formed inside the bag-shaped body by a welded portion in which opposing sheet surfaces of at least two aluminum sheets are welded together. The battery pack according to claim 1 or 2,
The battery pack further includes a battery case that houses the battery module and the cooling mechanism,
The battery pack, wherein the cooling mechanism is arranged between a side portion of the battery module or an upper portion of the battery module and the battery case.

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