Patent Application
20230097119
This nonprovisional application claims priority to Japanese Patent Application No. 2021-155486 filed on Sep. 24, 2021 with the Japan Patent Office, the entire contents of which are hereby incorporated by reference.
The present disclosure relates to a power storage device mounted on a vehicle, and a method for manufacturing the power storage device.
As a conventional power storage device, Japanese Patent Laying-Open No. 2020-053148 discloses a power storage device which includes a power storage stack and a cooler having a plurality of main cooling surfaces and recesses each provided between the plurality of main cooling surfaces, and in which a gel heat conduction member is disposed between the power storage stack and the plurality of main cooling surfaces, in a configuration in which the power storage stack and the cooler are disposed within a housing case.
Unlike the power storage device in Japanese Patent Laying-Open No. 2020-053148, there may be a case where a cooler is disposed outside a housing case. In such a case, it is conceivable to bring a cooler into close contact with a bottom portion of the housing case via a heat conduction member. When the heat conduction member contains air and most of the air cannot be discharged to the outside, adhesiveness of the cooler with respect to a lower case is reduced. Further, when most of the air remains in the heat conduction member, the area of the heat conduction member is also small, and cooling efficiency is reduced.
The present disclosure has been made in view of the aforementioned problem, and an object of the present disclosure is to provide a power storage device that can improve adhesiveness of a cooler with respect to a lower case, and can maintain good cooling efficiency, in a configuration in which the cooler is disposed outside the lower case.
A power storage device based on the present disclosure includes a lower case including a bottom portion having an inner surface and an outer surface opposite to each other, one or more power storage stacks thermally contacting the inner surface of the bottom portion, a cooler disposed below the bottom portion for cooling the one or more power storage stacks, and a heat conduction member provided between the outer surface of the bottom portion and the cooler. The cooler includes one or more cooling portions provided to correspond to the one or more power storage stacks, and a pair of holding portions holding the one or more cooling portions. Each of the one or more cooling portions is provided to bridge the pair of holding portions. The heat conduction member includes a pair of first linear portions disposed between the pair of holding portions and the bottom portion and extending along the pair of holding portions, and a plurality of second linear portions disposed between each of the one or more cooling portions and the bottom portion and extending along the cooling portion. The plurality of second linear portions are provided side by side in a cross direction crossing a direction in which the cooling portion extends. Each of the one or more cooling portions has a cooling surface contacting the plurality of second linear portions. In a cross section of each of the one or more cooling portions perpendicular to the direction in which the cooling portion extends, a total sum of widths of air layers each formed between the plurality of second linear portions is less than or equal to 14% of a width of the cooling surface.
According to the configuration described above, it is possible to let air escape from gaps between the pair of first linear portions and the plurality of second linear portions to the outside, before the pair of first linear portions are connected to the plurality of second linear portions, when the heat conduction member is sandwiched between the bottom portion of the lower case and the cooler, and thereby adhesiveness of the cooler with respect to the lower case can be improved. Further, by setting the total sum of the widths of the air layers to less than or equal to 14% of the width of the cooling surface, the plurality of second linear portions constituting the heat conduction member can have sufficient areas, and thereby good cooling efficiency can be maintained.
In the power storage device based on the present disclosure, the plurality of second linear portions may include three second linear portions arranged in the cross direction. In this case, a width parallel to the cross direction, of a second linear portion located at center in the cross direction, of the three second linear portions, may be larger than a width parallel to the cross direction, of second linear portions located on both sides in the cross direction, of the three second linear portions.
According to the configuration described above, by setting the width of the second linear portion located at the center in the cross direction to be larger than the width of the second linear portions located on the both sides in the cross direction, the ratio of the air layers each formed between the plurality of second linear portions can be reduced.
In the power storage device based on the present disclosure, each of the plurality of second linear portions includes both end portions, and a central portion located between the both end portions, in the direction in which the cooling portion extends. In this case, a width of the both end portions parallel to the cross direction may be larger than a width of the central portion parallel to the cross direction.
According to the configuration described above, since the width of the both end portions of each of the plurality of second linear portions connected to the pair of first linear portions is larger than the width of the central portion of each of the plurality of second linear portions, water from the outside can be suppressed from entering from the both end portions of the plurality of second linear portions into between each cooling portion and the bottom portion.
In the power storage device based on the present disclosure, the heat conduction member may have moisture permeability.
According to the configuration described above, moisture contained in the air layers can be discharged to the outside via the heat conduction member, and thereby the cooler can be prevented from rusting.
A method for manufacturing a power storage device based on the present disclosure includes preparing a lower case including a bottom portion having an inner surface and an outer surface opposite to each other, preparing a cooler, and forming a heat conduction member between the outer surface of the bottom portion and the cooler. In preparing the cooler, the cooler including one or more cooling portions each having a cooling surface, and a pair of holding portions holding the one or more cooling portions such that each of the one or more cooling portions bridges the pair of holding portions, is prepared. Forming the heat conduction member includes forming a pair of first linear portions extending between the pair of holding portions and the bottom portion, along the pair of holding portions, and a plurality of second linear portions extending between each of the one or more cooling portions and the bottom portion, along the cooling portion. In forming the pair of first linear portions and the plurality of second linear portions, the plurality of second linear portions are formed to contact the cooling surface and to be arranged in a cross direction crossing a direction in which the cooling portion extends, and the plurality of second linear portions are formed such that, in a cross section of each of the one or more cooling portions perpendicular to the direction in which the cooling portion extends, a total sum of widths of air layers each formed between the plurality of second linear portions is less than or equal to 14% of a width of the cooling surface.
According to the configuration described above, it is possible to let air escape from gaps between the pair of first linear portions and the plurality of second linear portions to the outside, before the pair of first linear portions are connected to the plurality of second linear portions, when the pair of first linear portions and the plurality of second linear portions are formed in forming the heat conduction member, and thereby adhesiveness of the cooler with respect to the lower case can be improved. Further, by setting the total sum of the widths of the air layers to less than or equal to 14% of the width of the cooling surface, the plurality of second linear portions constituting the heat conduction member can have sufficient areas, and thereby good cooling efficiency can be maintained.
In the method for manufacturing the power storage device based on the present disclosure, forming the pair of first linear portions and the plurality of second linear portions may include applying the heat conduction member such that a pair of first lines that are to serve as the pair of first linear portions are formed on the outer surface of the bottom portion at portions corresponding to the pair of holding portions, and a plurality of second lines that are to serve as the plurality of second linear portions are formed on the outer surface of the bottom portion at a portion corresponding to each of the one or more cooling portions. In some embodiments, in applying the heat conduction member, the plurality of second lines are formed to form gaps between the plurality of second lines and the pair of first lines, and to extend along the cooling portion with a spacing in the cross direction.
According to the configuration described above, the pair of first linear portions and the plurality of second linear portions are formed by connecting the pair of first lines and the plurality of second lines. By forming the plurality of second lines to form the gaps between the plurality of second lines and the pair of first lines, and to extend along the cooling portion with a spacing in the cross direction, it is possible to let the air escape from the gaps between the pair of first lines and the plurality of second lines to the outside, when the pair of first lines and the plurality of second lines are connected to form the pair of first linear portions and the plurality of second linear portions. Thus, adhesiveness of the cooler with respect to the lower case can be improved.
In some embodiments, the method for manufacturing the power storage device based on the present disclosure, forming the pair of first linear portions and the plurality of second linear portions includes sandwiching the pair of first lines and the plurality of second lines between the cooler and the bottom portion, and pressing and enlarging the plurality of second lines sandwiched between the cooler and the bottom portion, using a roller device.
According to the configuration described above, by pressing and enlarging the plurality of second lines with the roller device, it is possible to let air located between the plurality of second lines escape from the gaps between the plurality of second lines and the pair of first lines to the outside. Further, by pressing and enlarging the plurality of second lines, the plurality of second linear portions are formed with large areas.
In the method for manufacturing the power storage device based on the present disclosure, in pressing and enlarging the plurality of second lines using the roller device, rollers of the roller device may be moved, while being rotated, from one end side toward another end side of the plurality of second lines, to press the cooler against the bottom portion from a side opposite to a side on which the heat conduction member is located.
According to the configuration described above, the plurality of second lines can be easily pressed to be enlarged using the rollers.
In the method for manufacturing the power storage device based on the present disclosure, as the heat conduction member, a member having moisture permeability may be used.
According to the configuration described above, moisture contained in the air layers can be discharged to the outside via the heat conduction member, and thereby the cooler can be prevented from rusting.
The foregoing and other objects, features, aspects and advantages of the present disclosure will become more apparent from the following detailed description of the present disclosure when taken in conjunction with the accompanying drawings.
Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. It should be noted that, in the embodiment described below, identical or common parts will be designated by the same reference numerals in the drawings, and the description thereof will not be repeated.
(Power Storage Device)
Power storage device 1 in accordance with the embodiment is mounted on a hybrid vehicle that can run using motive power of at least one of a motor and an engine, or an electrically powered vehicle that runs using a driving force obtained by electrical energy.
As shown in
The plurality of power storage stacks 10 each include a plurality of power storage cells 12 arranged in a predetermined arrangement direction (a DR1 direction). It should be noted that, in a mounted state where power storage device 1 is mounted on the vehicle, DR1 direction is parallel to a width direction of the vehicle, for example.
Each power storage cell 12 is, for example, a secondary battery such as a nickel-hydrogen battery or a lithium ion battery. Power storage cell 12 has a rectangular shape, for example. Power storage cell 12 may be a power storage cell using a liquid electrolyte, or a power storage cell using a solid electrolyte. Further, power storage cell 12 may be a unit capacitor configured to store power.
The plurality of power storage stacks 10 are disposed side by side with a spacing in a direction perpendicular to the arrangement direction (i.e., in a DR2 direction). In the mounted state, DR2 direction is parallel to a front-rear direction of the vehicle, for example.
Housing case 20 houses the plurality of power storage stacks 10. Housing case 20 includes an upper case 21 and a lower case 22.
Upper case 21 has a substantially box shape opened downward. Upper case 21 may be made of a metal material. Further, upper case 21 may be made of a resin material for weight reduction.
Lower case 22 has a substantially box shape opened upward. Lower case 22 is made of a metal material. In some embodiments, lower case 22 has good heat conductivity.
Lower case 22 has a bottom portion 23. The plurality of power storage stacks 10 are mounted on bottom portion 23. Bottom portion 23 has an inner surface 23a and an outer surface 23b opposite to each other. Inner surface 23a faces toward the plurality of power storage stacks 10. Outer surface 23b faces opposite to a side on which the plurality of power storage stacks 10 are located.
Inner heat conduction layer 60 is disposed between each power storage stack 10 and inner surface 23a. Inner heat conduction layer 60 also functions as an adhesion layer, and adheres and fixes each power storage stack 10 to bottom portion 23. Each power storage stack 10 is brought into thermal contact with inner surface 23a by inner heat conduction layer 60.
Inner heat conduction layer 60 is made of a resin member having heat conductivity. As inner heat conduction layer 60, for example, an adhesive containing a silicone-based resin, an acrylic-based resin, an urethane resin, an epoxy resin, or the like can be adopted.
Cooler 30 is a device for cooling the plurality of power storage stacks 10. A refrigerant flow path through which a refrigerant flows is provided inside cooler 30. The refrigerant flow path is connected to a refrigerant introducing portion 61 and a refrigerant discharging portion 62. The refrigerant introduced from refrigerant introducing portion 61 into the refrigerant flow path cools the plurality of power storage stacks 10, and is discharged from refrigerant discharging portion 62.
Cooler 30 is disposed below bottom portion 23 of lower case 22. Cooler 30 is made of a metal material such as aluminum. A detailed structure of cooler 30 will be described later using
Heat conduction member 40 is disposed between outer surface 23b of bottom portion 23 and cooler 30. Via heat conduction member 40, bottom portion 23, and inner heat conduction layer 60, the plurality of power storage stacks 10 are cooled by cooler 30. Heat conduction member 40 also functions as an adhesion layer that adheres bottom portion 23 and cooler 30. As heat conduction member 40, for example, an adhesive containing a silicone-based resin, an acrylic-based resin, an urethane resin, an epoxy resin, or the like can be adopted. A detailed structure of heat conduction member 40 will be described later using
Share panel 50 is disposed to cover cooler 30 from a lower side. Share panel 50 protects cooler 30 and suppresses cooler 30 from being wetted by water. Share panel 50 is made of a metal material. Share panel 50 includes a cover panel.
Cooler 30 includes a pair of holding portions 31, a plurality of cooling portions 32, and a projecting portion 34. The refrigerant flow path is routed inside the pair of holding portions 31, the plurality of cooling portions 32, and projecting portion 34.
The pair of holding portions 31 extend along DR2 direction. The pair of holding portions 31 are disposed to be spaced from each other in DR1 direction. The pair of holding portions 31 hold the plurality of cooling portions 32.
The plurality of cooling portions 32 are disposed at positions respectively corresponding to the plurality of power storage stacks 10. The plurality of cooling portions 32 are provided corresponding to the number of the plurality of power storage stacks 10. Each of the plurality of cooling portions 32 is provided to bridge the pair of holding portions 31. The plurality of cooling portions 32 are disposed side by side with a spacing in DR2 direction.
Projecting portion 34 is provided to project from one end side of the pair of holding portions 31 toward one side in DR2 direction. Projecting portion 34 has a substantially C shape. Projecting portion 34 is provided with refrigerant introducing portion 61 and refrigerant discharging portion 62 described above.
Heat conduction member 40 includes a pair of first linear portions 41 disposed between the pair of holding portions 31 and bottom portion 23, a plurality of second linear portions 42 disposed between each of the plurality of cooling portions 32 and bottom portion 23, and a third linear portion 44.
The pair of first linear portions 41 are provided to extend along the pair of holding portions 31. Specifically, the pair of first linear portions 41 are provided to extend along DR2 direction.
The plurality of second linear portions 42 are provided to extend along each cooling portion 32. Specifically, the plurality of second linear portions 42 are provided to extend along DR1 direction. The plurality of second linear portions 42 are disposed side by side in a cross direction crossing a direction in which each cooling portion 32 extends. In the present embodiment, between each cooling portion 32 and bottom portion 23, the plurality of second linear portions 42 include three second linear portions 42 arranged in the cross direction. The cross direction is parallel to DR2 direction, for example. Air layers 43 are each formed between second linear portions 42 adjacent to each other in the cross direction.
It should be noted that, although
In the direction in which each cooling portion 32 extends (DR1 direction), each of the plurality of second linear portions 42 includes both end portions 42a and 42b, and a central portion 42c located between both end portions 42a and 42b. Both end portions 42a and 42b are connected to the pair of first linear portions 41. A width of both end portions 42a and 42b parallel to the cross direction is larger than a width of central portion 42c parallel to the cross direction. This can suppress water from the outside from entering from both end portions 42a and 42b of the plurality of second linear portions 42 into between each cooling portion 32 and bottom portion 23.
Third linear portion 44 is disposed between projecting portion 34 and bottom portion 23. Third linear portion 44 is provided to project from one end side of the pair of first linear portions 41 toward the one side in DR2 direction. Third linear portion 44 has a substantially C shape.
As shown in
On cooling surface 32a, a width L1 parallel to the cross direction, of second linear portion 42 located at the center in the cross direction, of the three second linear portions 42, is larger than a width L2 parallel to the cross direction, of second linear portions 42 located on both sides in the cross direction, of the three second linear portions 42. Cooling surface 32a has a width L3 in DR2 direction.
Here, in a cross section of cooling portion 32 perpendicular to the direction in which cooling portion 32 extends, a total sum (L3−L1−2×L2) of widths of air layers 43 each formed between the plurality of second linear portions 42 is less than or equal to approximately 14% of the width (L3) of cooling surface 32a.
By setting the total sum of the widths of air layers 43 to less than or equal to 14% of the width of cooling surface 32a in this manner, the plurality of second linear portions 42 constituting heat conduction member 40 can have sufficient areas, and thereby good cooling efficiency can be maintained.
Further, by setting width L1 of second linear portion 42 located at the center in the cross direction to be larger than width L2 of second linear portions 42 located on the both sides in the cross direction, the ratio of air layers 43 each formed between the plurality of second linear portions 42 can be reduced. Thereby, cooling efficiency can be further improved.
In addition, by forming the plurality of second linear portions 42 side by side in the cross direction between each cooling portion 32 and bottom portion 23, it is possible to let air escape from gaps between the pair of first linear portions 41 and the plurality of second linear portions 42 to the outside, before the pair of first linear portions 41 are connected to the plurality of second linear portions 42, when heat conduction member 40 is sandwiched between bottom portion 23 of lower case 22 and cooler 30, as described later. Thereby, adhesiveness of cooler 30 with respect to lower case 22 can be improved.
It should be noted that, although the above description illustrates the case where width L1 of second linear portion 42 located at the center in the cross direction is larger than width L2 of second linear portions 42 located on the both sides in the cross direction, the present disclosure is not limited thereto, and the three second linear portions 42 may have a substantially equal width. That is, width L1 may be substantially equal to width L2.
(Method for Manufacturing Power Storage Device)
As shown in
In manufacturing power storage device 1, first, in step (S10), lower case 22 is prepared. Specifically, lower case 22 including bottom portion 23 having inner surface 23a and outer surface 23b opposite to each other is prepared.
Subsequently, in step (S11), cooler 30 is prepared. Specifically, cooler 30 including the plurality of cooling portions 32 each having cooling surface 32a, and the pair of holding portions 31 holding the plurality of cooling portions 32 such that each of the plurality of cooling portions 32 bridges the pair of holding portions 31, is prepared. The plurality of cooling portions 32 are disposed side by side with a spacing in DR2 direction as described above, and projecting portion 34 projecting in the substantially C shape on the one side in DR2 direction is provided from the one end side of the pair of holding portions 31.
It should be noted that step (S11) may be performed before step (S10), or may be performed in parallel with step (S10).
Subsequently, in step (S13), heat conduction member 40 is formed. Step (S13) includes a step (S20) of forming the pair of first linear portions 41 and the plurality of second linear portions 42. Step (S20) has a step (S21) of applying a heat conduction member 70 (more specifically, a precursor of heat conduction member 40) such that a pair of first lines 71 (see
In step (S20), the pair of first linear portions 41 extending between the pair of holding portions 31 and bottom portion 23, along the pair of holding portions 31, and the plurality of second linear portions 42 extending between each of the plurality of cooling portions 32 and bottom portion 23, along cooling portion 32, are formed.
Specifically, the plurality of second linear portions 42 are formed to contact cooling surface 32a and to be arranged in the cross direction crossing the direction in which cooling portion 32 extends, and the plurality of second linear portions 42 are formed such that, in a cross section of each of the plurality of cooling portions 32 perpendicular to the direction in which cooling portion 32 extends, the total sum of the widths of air layers 43 each formed between the plurality of second linear portions 42 is less than or equal to 14% of the width of cooling surface 32a.
In order to form the pair of first linear portions 41 and the plurality of second linear portions 42, first, in step (S21), heat conduction member 70 is applied, as described above.
As shown in
It should be noted that, when heat conduction member 70 is applied on outer surface 23b, lower case 22 is disposed such that outer surface 23b faces upward.
Furthermore, in step (S21), the plurality of second lines 72 are formed to form gaps between the plurality of second lines 72 and the pair of first lines 71, and to extend along cooling portion 32 with a spacing in the cross direction.
On this occasion, the plurality of second lines 72 are formed to include three second lines 72 on outer surface 23b of bottom portion 23 at a portion corresponding to each cooling portion 32. For example, the three second lines 72 are formed such that the width of second line 72 located at the center in the cross direction, of the three second lines 72, is larger than the width of second lines 72 located on both sides in the cross direction, of the three second lines 72. It should be noted that the three second lines 72 may be formed such that they have the same width in the cross direction.
In some embodiments, the gap is smaller than the diameter of a roller 81 (see
Subsequently, as shown in
Subsequently, as shown in
Roller device 80 includes a plurality of rollers 81, and a shaft portion 82 rotatably supporting the plurality of rollers 81. The plurality of rollers 81 are provided at positions corresponding to respective cooling portions 32.
In step (S23), specifically, rollers 81 are moved, while being rotated, from the one end side toward the other end side of the plurality of second lines 72 as indicated by arrows in
By pressing and enlarging the plurality of second lines 72 with roller device 80 in this manner, it is possible to let air located between the plurality of second lines 72 escape from the gaps between the plurality of second lines 72 and the pair of first lines 71 to the outside, before the pair of first lines 71 are connected to the plurality of second lines 72. Further, by pressing and enlarging the plurality of second lines 72, the plurality of second linear portions 42 are formed with large areas, and the total sum of the widths of air layers 43 becomes less than or equal to 14% of the width of cooling surface 32a.
The pair of first linear portions 41 and the plurality of second linear portions 42 are formed by connecting the pair of first lines 71 and the plurality of second lines 72. By forming the plurality of second lines 72 to form the gaps between the plurality of second lines 72 and the pair of first lines 71, and to extend along cooling portion 32 with a spacing in the cross direction, it is possible to let the air escape from the gaps between the pair of first lines 71 and the plurality of second lines 72 to the outside, when the pair of first lines 71 and the plurality of second lines 72 are connected to form the pair of first linear portions 41 and the plurality of second linear portions 42. Thus, adhesiveness of cooler 30 with respect to lower case 22 can be improved.
Further, since rigidity of cooler 30 is smaller than rigidity of bottom portion 23, the plurality of second lines 72 can be easily pressed to be enlarged by pressing cooler 30 against bottom portion 23 while rotating rollers 81.
Subsequently, as shown in
Subsequently, as shown in
Subsequently, as shown in
Through the steps as described above, power storage stack 10 in accordance with the embodiment can be manufactured.
(Other Variations)
Although the embodiment described above illustrates the case where heat conduction member 70 is applied on outer surface 23b of bottom portion 23 in the step (S21) of applying heat conduction member 70, the present disclosure is not limited thereto, and heat conduction member 70 may be applied to cooler 30. In this case, heat conduction member 70 is applied such that the pair of first lines 71 that are to serve as the pair of first linear portions 41 are formed on the pair of holding portions 31, and the plurality of second lines 72 that are to serve as the plurality of second linear portions 42 are formed on each of the plurality of cooling portions 32.
Although the embodiment described above illustrates the case where power storage stacks 10 are provided in plural numbers, the number of power storage stacks 10 may be one. In this case, the number of cooling portions 32 may also be one. Thus, it is satisfactory as long as one or more cooling portions 32 are provided.
Although the embodiment of the present disclosure has been described, it should be understood that the embodiment disclosed herein is illustrative and non-restrictive in every respect. The scope of the present disclosure is defined by the scope of the claims, and is intended to include any modifications within the scope and meaning equivalent to the scope of the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-155486 | Sep 2021 | JP | national |
