Power storage module with cooling member

A power storage module includes: a power storage element; a cooling member that is stacked on the power storage element and has a sealing body hermetically sealing a coolant and an absorption member disposed in the sealing body to absorb the coolant; and a heat transfer plate that is stacked on the power storage element with the cooling member sandwiched therebetween. The heat transfer plate is provided with protrusion portions that protrude to the cooling member side.

TECHNICAL FIELD

The present description discloses a technique for cooling a power storage element.

BACKGROUND ART

There has been conventionally known a technique for cooling a power storage element. Patent Document 1 describes that a battery module is stored in a pack case and positive terminals and negative terminals of a plurality of cells are electrically connected together via bus bars. When a coolant charged in the lower portion of the pack case becomes evaporated and condensed in the upper portion of the pack case, the battery is cooled.

RELATED ART DOCUMENT

Patent Document

DISCLOSURE OF THE PRESENT INVENTION

Problem to be Solved by the Invention

According to the technique described in Patent Document 1, the coolant is to be evaporated and condensed in the pack case, and thus the entire pack case needs to be sealed. This causes a problem that it is not easy to simplify the structure for cooling.

The technique disclosed herein is completed under the foregoing circumstances, and an object of the technique is to simplify the structure for cooling.

Means for Solving the Problem

A power storage module described herein includes: a power storage element; a cooling member that is stacked on the power storage element and has a sealing body hermetically sealing a coolant and an absorption member disposed in the sealing body to absorb the coolant; and a heat transfer plate that is stacked on the power storage element with the cooling member sandwiched therebetween. The heat transfer plate is provided with a protrusion portion that protrudes to the cooling member side.

According to the foregoing configuration, it is possible to dissipate heat of the power storage element to the outside via the cooling member in which the coolant is sealed in the sealing body and the heat transfer plate. Accordingly, as compared to the configuration in which the coolant is charged in a case where the power storage element is stored, for example, the case does not necessarily need to be sealed. This makes it possible to simplify the structure for cooling.

In the configuration in which the cooling member includes the absorption member to absorb the coolant in the sealing body, when the cooling member is sandwiched between the power storage element and the heat transfer plate, the sealing body of the cooling member receives pressure from both sides, and the entire absorption member becomes crushed and do not form a path of the coolant for facilitating the movement of the coolant. In this case, there is a fear of a decrease in cooling performance.

According to the present configuration, the heat transfer plate is provided with the protrusion portion protruding to the cooling member side, and thus the internal absorption member is less prone to become crushed even with a force to sandwich the cooling member between the power storage element and the heat transfer plate. Accordingly, it is possible to suppress a decrease in cooling performance caused by the crushing of the absorption member to absorb the coolant.

Embodiments of the technique described herein are preferably as described below.

The protrusion portion may extend from one side edge portion to another side edge portion opposite to the one side edge portion of the heat transfer plate.

Accordingly, the sealing body and the absorption member deform corresponding to the shape of the protrusion portion to form a path of the coolant in the sealing body along the direction of extension of the protrusion portion. This allows the coolant to move along the direction of extension of the protrusion portion, thereby to facilitate the movement of the coolant and improve cooling performance.

The sealing body may be configured such that a first sheet portion and a second sheet portion are opposed to each other with the absorption member sandwiched therebetween, and the protrusion portion may protrude toward a position of a boundary portion between the first sheet portion and the second sheet portion in the sealing body.

Accordingly, the protrusion portion can support the boundary portion between the first sheet portion and the second sheet portion where the absorption member is relatively prone to become crushed. This suppresses a decrease in cooling performance caused by the crushing of the entire absorption member.

Advantageous Effect of the Invention

According to the technique described herein, it is possible to simplify the structure for cooling.

MODE FOR CARRYING OUT THE INVENTION

First Embodiment

A first embodiment will be described with reference toFIGS. 1 to 6. A power storage module10in the present embodiment is mounted in a vehicle such as an electric car or hybrid car, for example, to supply electric power to a load such as a motor. Although the power storage module10can be disposed in any orientation, the following descriptions are based on the assumption that an X direction is a leftward direction, a Y direction is a forward direction, and a Z direction is an upward direction.

As illustrated inFIG. 3, the power storage module10includes: a plurality of (six in the present embodiment) power storage elements11; a plurality of (six in the present embodiment) cooling members20that are stacked on the power storage elements11to cool the power storage elements11; and a plurality of (six in the present embodiment) heat transfer plates30that are stacked between the cooling members20and the power storage elements11to transmit heat of the cooling members20and the power storage elements11.

Each of the power storage elements11is formed by sandwiching a power storage factor not illustrated between a pair of battery laminate sheets and bonding side edges of the battery laminate sheets in a liquid-tight manner by a publicly known method such as heat welding. As illustrated inFIG. 2, a positive electrode terminal12A and a negative electrode terminal12B in metallic foil form protrude from the front end edge of each of the power storage elements11, from inside to outside of the battery laminate sheets in a liquid-tight state with the inner surface of the battery laminate sheet. The electrode terminal12A and the electrode terminal12B of each of the power storage elements11are disposed with a space therebetween and are electrically connected to the internal power storage factor.

The plurality of power storage elements11are vertically aligned and the adjacent power storage elements11are disposed such that one electrode terminal12A is positioned next to the other electrode terminal12B. The adjacent electrode terminal12A and electrode terminal12B are electrically connected together via a plurality of (five in the present embodiment) U-shaped connection members13. The electrode terminals12A,12B and the connection members13are connected together by a publicly known method such as laser welding, ultrasonic welding, or brazing, for example. The adjacent electrode terminals12A and12B are connected by the connection members13, so that the plurality of power storage elements11are connected in series.

In the present embodiment, examples of the power storage elements11include secondary batteries such as lithium-ion secondary batteries or nickel-metal-hydride secondary batteries, capacitors such as electric double-layer capacitors or lithium ion capacitors, and any type can be selected as necessary.

As illustrated inFIG. 3, each of the cooling members20includes a coolant21that varies between liquid and gaseous states, an absorption member22that absorbs the coolant21, and a sealing body25that hermetically seals the coolant21and the absorption member22. The coolant21can be one or more selected from a group consisting of perfluorocarbon, hydrofluoroether, hydrofluoroketone, fluorine inert liquid, water, and alcohols such as methanol and ethanol, for example. The coolant21may have insulating properties or conductive properties. The amount of the coolant21sealed in the sealing body25can be selected as necessary.

Each of the absorption members22has a substantially rectangular sheet shape and is formed from a material configured to absorb the coolant21. The absorption member22may be formed by processing a material configured to absorb the coolant21in fiber form and weaving into a fabric or may be formed from a non-woven fabric. The form of the non-woven fabric may be fiber sheet, web (thin film sheet made of fiber only), or bat (blanket-like fiber). The material for the absorption member22may be natural fiber, synthetic fiber formed from synthetic resin, or a combination of natural fiber and synthetic fiber.

The cooling member20is disposed in a wide region as compared to the region overlapping the power storage element11, and thus the absorption member22in the sealing body25includes an absorption extension portion23that is extended from the region overlapping the power storage element11to a region not overlapping the power storage element11.

As illustrated inFIG. 5, the sealing body25can be formed by stacking and joining (bonding) together substantially rectangular first sheet portion26A and second sheet portion26B in a liquid-tight manner by a publicly known method such as adhesion, welding, or deposition, for example. Each of the first sheet portion26A and the second sheet portion26B is formed by laminating a synthetic resin film to the both sides of a metallic sheet. The metal constituting the metallic sheet can be any metal selected from aluminum, aluminum alloy, copper, and copper alloy as necessary. The synthetic resin constituting a synthetic resin film can be any synthetic resin selected from polyolefins such as polyethylene and polypropylene, polyesters such as polybutylene terephthalate and polyethylene terephthalate, polyamides such as nylon 6 and nylon 6, 6 as necessary. The sealing body25according to the present embodiment is formed by stacking and thermally fusing the surfaces of the first sheet portion26A and the second sheet portion26B with synthetic resin films stacked.

The sealing body25has a peripheral edge portion where the first sheet portion26A covering the upper side of the absorption member22and the second sheet portion26B covering the lower side of the absorption member22are connected, as a boundary portion25A. The upper surface of the first sheet portion26A is in contact with the lower surface of the power storage element11and the lower surface of the second sheet portion26B is in contact with the upper surface of the heat transfer plate30.

As illustrated inFIG. 3, a portion of the first sheet portion26A extended in a region not overlapping the power storage element11and covering the absorption extension portion23of the absorption member22is set as a bulging portion28that is configured to bulge and deform by evaporation of the coolant21in the sealing body25. The bulging portion28is formed when the sealing body25becomes deformed and bulged with a rise in the inner pressure of the sealing body25caused by evaporation of the coolant21in the sealing body25. The portion of the sealing body25other than the bulging portion28does not bulge or deform even with a rise in the inner pressure caused by evaporation of the coolant21in the sealing body25because the portion is in contact with the power storage element11and the heat transfer plate30and is restricted in bulging.

Each of the heat transfer plates30is stacked on the power storage element11with the cooling member20sandwiched therebetween and is rectangular in shape, and is formed from a member with high heat conductivity such as aluminum, aluminum alloy, copper, or copper alloy, as illustrated inFIG. 6. The heat transfer plate30has a flat plate-shaped main body31that is in contact with the power storage element11and the sealing body25and a partition wall34that is bent in a direction orthogonal to the main body31. The main body31is provided with a plurality of (four in the present embodiment) protrusion portions32A to32D that protrude to the cooling member20side to deform the second sheet portion26B of the sealing body25.

As illustrated inFIGS. 4 and 5, the plurality of protrusion portions32A to32D are substantially the same in plate thickness as the main body31and have a semi-arc cross section shape, and are disposed in parallel with a predetermined spacing therebetween in a front-back direction and entirely protrude upward at a constant height. The protrusion portions32A and32D at the end portions as seen in the alignment direction press the second sheet portion26B on the boundary portion25A side (the inner edge portion side of the sealing body25) between the first sheet portion26A and the second sheet portion26B to deform the second sheet portion26B and the internal absorption member22. The protrusion portions32A to32D have a strength to such a degree that the protrusion portions32A to32D would not suffer plastic deformation even with an external force (for example, bulging of the power storage element11and the like) applied to at least the sealing body25.

The front and back end portions of the main body31have plate-shaped protrusion pieces33. Each of the protrusion pieces33has a rectangular through hole that is used for fixation to a case not illustrated, for example. The partition wall34is in surface contact with the side surface of the heat dissipation member40. Accordingly, the heat of the power storage elements11transfers to the vertically adjacent heat transfer plates30via the bulging portions28of the cooling members20and transfers from the partition wall34to the heat dissipation member40, and then is dissipated from the heat dissipation member40to the outside. Each of the heat transfer plates30can be formed by punching and bending a metal plate material by a pressing machine.

As illustrated inFIG. 3, the heat dissipation member40is disposed on a lateral side of the power storage module10to receive heat from the heat transfer plates30and dissipate the heat to the outside. The heat dissipation member40is formed from a metal such as aluminum or aluminum alloy and has an inlet opening and an outlet opening for a cooling material not illustrated. A cooling liquid as a cooling material is introduced into the lower inlet opening and discharged from the upper outlet opening. The cooling liquid circulates through a heat dissipation path not illustrated to dissipate heat having been transferred to the cooling liquid to the outside. The heat dissipation member40may have a pipe (not illustrated) entirely extending inside with a plurality of folds for passage of the cooling liquid. In the present embodiment, the cooling liquid is water. However, the cooling liquid is not limited to this but may be a liquid such as oil. Alternatively, the cooling liquid may be an antifreeze liquid. In addition, the cooling liquid is not limited to a liquid but may be a gas.

The present embodiment produces the following operations and advantageous effects.

The power storage module10includes: the power storage elements11; the cooling members20that are stacked on the power storage elements11and have the sealing body25hermetically sealing the coolant21and the absorption member22disposed in the sealing body25to absorb the coolant21; and the heat transfer plates30that are stacked on the power storage elements11with the cooling members20sandwiched therebetween. Each of the heat transfer plates30is provided with the protrusion portions32A to32D that protrude to the cooling member20side.

According to the present embodiment, it is possible to dissipate the heat of the power storage elements11via the cooling members20in which the coolant21is sealed in the sealing body25and the heat transfer plates30. Accordingly, as compared to the configuration in which the coolant21is charged in a case where the power storage elements11are stored, for example, the case does not necessarily need to be sealed. This makes it possible to simplify the structure for cooling. In the configuration in which the absorption member22to absorb the coolant21is disposed in the sealing body25of the cooling member20, when the cooling member20is sandwiched between the power storage element11and the heat transfer plate30, the sealing body25of the cooling member20receives pressure from both sides, and the entire absorption member22becomes crushed and does not form a path of the coolant21for facilitating the movement of the coolant21. In this case, there is a fear of a decrease in cooling performance.

According to the present embodiment, each of the heat transfer plates30is provided with the protrusion portions32A to32D protruding to the cooling member20side, and thus the internal absorption member22is entirely less prone to become crushed even with a force to sandwich the cooling member20between the power storage element11and the heat transfer plate30. Accordingly, it is possible to suppress a decrease in cooling performance caused by the crushing of the absorption member22to absorb the coolant21.

The protrusion portions32A to32D extend from a (one) side edge portion on the heat dissipation member40side of the heat transfer plate30to another side edge portion on a side opposite to the heat dissipation member40side.

Accordingly, the sealing body25and the absorption member22deform corresponding to the shapes of the protrusion portions32A to32D to form a path of the coolant21in the sealing body25along the direction of extension of the protrusion portions32A to32D. This allows the coolant21to move along the direction of extension of the protrusion portions32A to32D, thereby to facilitate the movement of the coolant21and improve cooling performance.

The sealing body25is configured such that the first sheet portion26A and the second sheet portion26B are opposed to each other with the absorption member22sandwiched therebetween. The protrusion portions32A and32D protrude toward the position of the boundary portion25A between the first sheet portion26A and the second sheet portion26B.

Accordingly, the protrusion portions32A and32D can support the boundary portion25A between the first sheet portion26A and the second sheet portion26B where the absorption member22is relatively prone to become crushed. This suppresses a decrease in cooling performance caused by the crushing of the entire absorption member22.

Second Embodiment

A second embodiment will be described with reference toFIG. 7. In the second embodiment, protrusion portions52A to52D extending in a rectangular shape are provided along the outer peripheral edge portion of a heat transfer plate50. As for other components, the second embodiment is identical to the first embodiment. Thus, the components identical to those in the first embodiment will be given the reference symbols identical to those in the first embodiment and descriptions thereof will be omitted.

The heat transfer plate50has a rectangular plate shape and includes a flat plate-shaped main body51and a partition wall34. The main body51has the protrusion portions52A to52D protruding in a direction orthogonal to the plate surface. The protrusion portions52A to52D extend near the outer peripheral edge of the main body51along the outer peripheral edge without interruption over the entire periphery. According to the present embodiment, the protrusion portions52A to52D make the absorption member22less prone to become crushed on the peripheral edge portion side of the cooling member20where the absorption member22is relatively prone to become crushed, thereby suppressing a decrease in cooling performance.

Third Embodiment

A third embodiment will be described with reference toFIG. 8. In the third embodiment, a heat transfer plate60is provided with protrusion portions62A and62B extending in directions orthogonal to each other (crossing each other). As for other components, the third embodiment is identical to the first embodiment. Thus, the components identical to those in the foregoing embodiments will be given the reference symbols identical to those in the foregoing embodiments and descriptions thereof will be omitted. The heat transfer plate60has a rectangular plate shape and includes a flat plate-shaped main body61and a partition wall34. The main body61has the protrusion portions62A and62B protruding in a direction orthogonal to the plate surface. The protrusion portions62A and62B extend in directions orthogonal to each other from one edge portion to another edge portion opposite to the one edge portion of the heat transfer plate60(the main body61).

Other Embodiments

The technique described herein is not limited to the embodiments described above and illustrated in the drawings. For example, the following embodiments are included in the scope of the technique described herein:

(1) In the foregoing embodiments, the absorption member22is locally crushed by the protrusion portions32A to32D,52A to52D,62A,62B at their positions. However, the present disclosure is not limited to this configuration but the absorption member22may not be disposed at the positions of the protrusion portions32A to32D,52A to52D,62A,62B. For example, the absorption member22may be divided at the positions of the protrusion portions32A to32D,52A to52D,62A,62B.

(2) The protrusion portions32A to32D are formed by bending a metal plate material but the present disclosure is not limited to this. For example, the protrusion portions may be formed by locally thickening a heat transfer plate.

(3) The protrusion portions32A to32D,52A to52D,62A,62B extend linearly. However, the protrusion portions are not limited to this but may extend in a curved manner. There may be one protrusion portion or a plurality of protrusion portions arranged at intervals in the direction of extension of the protrusion portion. Alternatively, a plurality of protrusion portions may be discretely disposed.

(4) The numbers of the power storage elements, the cooling members, and the heat transfer plates are not limited to the numbers in the foregoing embodiments but can be changed as appropriate.

(5) The sealing body25is configured such that the separate first sheet portion26A and second sheet portion26B are bonded together. However, the sealing body25is not limited to this configuration. For example, one sheet member may be folded back to form a first sheet portion and a second sheet portion.

(6) The power storage module10may not include the heat dissipation member40. For example, the power storage module10may be covered with a metallic or synthetic resin case not illustrated, so that the heat of the power storage module10is dissipated via the case to the outside without the intervention of the heat dissipation member40. In addition, the case may be a part of the heat dissipation member40or the case may cover the entire power storage module10including the heat dissipation member40, for example. In this case, for example, the case may sandwich the power storage module10from the upper and lower sides to hold the power storage module10.

EXPLANATION OF SYMBOLS