Battery pack

Abstract

To provide a battery pack capable of cooling a battery cell while fully ensuring waterproof and dustproof functions.SOLUTION: A battery pack 100 includes a plurality of stacked battery cells 11, a case body 21 that defines an internal space 70 in which no forced air flow is formed and accommodates the plurality of battery cells 11 in the internal space 70, a duct body 31 that is disposed outside the case body 21 and connected to the case body 21, and a blower 41 that circulates air through the duct body 31.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a battery pack. [Background technology]

[0002] For example, JP 2017-37751 A (Patent Document 1) discloses a battery pack including a case, a battery pack disposed in the case, and an internal fan for circulating a heat exchange fluid in a circulation passage formed in the case. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-37751 A Summary of the Invention [Problem to be solved by the invention]

[0004] As disclosed in the above-mentioned Patent Document 1, a battery pack is known in which an assembled battery made up of a combination of multiple battery cells is cooled by air cooling. In such a battery pack, when cooling air is guided from the outside to the inside of a case body that houses the assembled battery, it is necessary to provide a vent hole in the case body. In this case, water or dust may enter the inside of the case body through the vent hole, and therefore the waterproof and dustproof functions of the battery pack cannot be sufficiently ensured.

[0005] SUMMARY OF THE PRESENTING EMBODIMENT An object of the present invention is to solve the above-mentioned problems and to provide a battery pack that is capable of cooling the battery cells while adequately ensuring waterproof and dustproof functions. [Means for solving the problem]

[0006] [1] A battery pack comprising: a plurality of stacked battery cells; a case body that defines an internal space in which no forced air flow is formed and accommodates the plurality of battery cells in the internal space; a duct body that is arranged outside the case body and connected to the case body; and a blower for circulating air through the duct body.

[0007] In a battery pack configured in this manner, a duct body through which air, a coolant for cooling the battery cells, flows is arranged outside the case body, while the internal space of the case body housing the multiple battery cells is designed to be a space in which no forced air flow is formed. This eliminates the need to provide a vent in the case body for letting air in and out of the internal space, thereby realizing a battery pack that can fully ensure waterproof and dustproof functions while simultaneously cooling the battery cells.

[0008] [2] The battery pack described in [1], wherein the case body has a bottom on which the plurality of battery cells are placed and a side portion rising from the bottom portion, and the duct body is connected to at least one of the bottom portion and the side portion.

[0009] According to a battery pack configured in this manner, heat dissipation from the multiple battery cells can be promoted through the bottom and / or side of the case body to which the duct body is connected.

[0010] [3] The battery pack described in [2], wherein the duct body is connected to the bottom and is arranged so as not to protrude from the peripheral portion of the case body when viewed from above.

[0011] According to a battery pack configured in this manner, it is possible to prevent the size of the battery pack from increasing when viewed from above due to the installation of the duct body.

[0012] [4] A battery pack described in any one of [1] to [3], wherein the duct body has an opening that opens the air flow path to the outside, and the blower device has a fan arranged opposite to the opening surface formed by the opening.

[0013] In a battery pack configured in this manner, when the fan is rotating, the air taken into the duct body through the opening serves as a coolant to promote heat dissipation from the multiple battery cells.

[0014] [5] The battery pack according to [4], wherein the fan is disposed inside the duct body.

[0015] According to the battery pack configured in this manner, there is no need to provide a separate case for accommodating the fan, and therefore the blower device can be configured simply.

[0016] [6] The battery pack described in [4] or [5], wherein the duct body extends in one direction, the opening includes a first opening and a second opening that open at one end and the other end of the duct body in the one direction, and the fan is positioned opposite an opening surface formed by at least one of the first opening and the second opening.

[0017] According to a battery pack configured in this manner, by forming an air flow in the duct body that flows between one end and the other end in the extension direction of the duct body, it is possible to promote heat dissipation from the multiple battery cells.

[0018] [7] A battery pack as described in [4] or [5], wherein the duct body extends in one direction, the opening includes a first opening and a second opening which open at one end and the other end of the duct body in the one direction, respectively, and a third opening which opens between the one end and the other end of the duct body in the one direction, and the fan is positioned opposite an opening surface formed by the third opening.

[0019] According to a battery pack configured in this manner, by forming an air flow in the duct body between the middle portion in the extension direction of the duct body and one end and the other end, heat dissipation from the multiple battery cells can be promoted.

[0020] [8] The battery pack according to [7], wherein the plurality of battery cells are stacked in the one direction.

[0021] A battery pack configured in this manner can suppress variations in cooling efficiency among a plurality of battery cells that are caused by air temperature differences between the upstream and downstream sides of the air flow.

[0022] [9] A battery pack according to any one of [1] to [8], wherein the duct body is made of a metal extrusion material.

[0023] According to the battery pack configured in this manner, the duct body is manufactured by extrusion molding of metal, so that the duct body can be manufactured easily. Effect of the Invention

[0024] As described above, according to the present invention, it is possible to provide a battery pack that is capable of cooling the battery cells while adequately ensuring waterproof and dustproof functions. [Brief description of the drawings]

[0025] [Figure 1] 1 is a cross-sectional view showing a battery pack according to an embodiment of the present invention. [Diagram 2] 2 is a perspective view showing a battery cell that constitutes the battery pack in FIG. 1. [Diagram 3] FIG. 2 is an exploded view showing the battery pack in FIG. [Figure 4] 1. FIG. 4 is a cross-sectional view showing a first modified example of the battery pack in FIG. [Diagram 5] 1. FIG. 4 is a cross-sectional view showing a second modified example of the battery pack in FIG. [Figure 6] 1. FIG. 4 is a cross-sectional view showing a third modified example of the battery pack in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described with reference to the accompanying drawings, in which the same or corresponding components are designated by the same reference numerals.

[0027] Fig. 1 is a cross-sectional view showing a battery pack in an embodiment of the present invention, Fig. 2 is a perspective view showing a battery cell constituting the battery pack in Fig. 1, Fig. 3 is an exploded view showing the battery pack in Fig. 1.

[0028] 1 to 3, a battery pack 100 is used as a power source for driving a vehicle such as a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), or a battery electric vehicle (BEV).

[0029] In this specification, for the convenience of explaining the structure of the battery pack 100, the stacking direction of the multiple battery cells 11 described later and the axis extending horizontally are referred to as the "Y-axis," the direction perpendicular to the Y-axis and extending horizontally are referred to as the "X-axis," and the axis extending vertically are referred to as the "Z-axis."

[0030] The battery pack 100 has a plurality of battery cells 11. The plurality of battery cells 11 are stacked in the Y-axis direction. The battery cells 11 are lithium ion batteries. The battery cells 11 are angular and have the shape of a rectangular thin plate. The plurality of battery cells 11 are stacked such that the Y-axis direction is the thickness direction of the battery cells 11.

[0031] The battery cell 11 has an exterior body 12. The exterior body 12 is made of a rectangular parallelepiped housing, and forms the external appearance of the battery cell 11. The exterior body 12 contains an electrode assembly and an electrolyte.

[0032] Exterior body 12 has a first side surface 13, a second side surface 14, a top surface 15, and a bottom surface 16. Each of first side surface 13 and second side surface 14 is a plane perpendicular to the Y axis. First side surface 13 and second side surface 14 face opposite each other in the Y axis direction. Each of first side surface 13 and second side surface 14 has the largest area among the multiple side surfaces that exterior body 12 has.

[0033] Top surface 15 and bottom surface 16 each consist of a plane perpendicular to the Z-axis. Top surface 15 faces upward. Bottom surface 16 faces downward. Top surface 15 is provided with a gas exhaust valve 17 for exhausting gas to the outside of exterior body 12 when the internal pressure of exterior body 12 exceeds a predetermined value due to gas generated inside exterior body 12.

[0034] The battery cell 11 further has electrode terminals 18, each of which is a pair of a positive terminal 18P and a negative terminal 18N. The electrode terminals 18 are provided on the top surface 15. The positive terminal 18P and the negative terminal 18N are provided apart from each other in the X-axis direction. The positive terminal 18P and the negative terminal 18N are provided on either side of the gas release valve 17 in the X-axis direction.

[0035] The multiple battery cells 11 are stacked such that the first side surfaces 13 face each other and the second side surfaces 14 face each other between the battery cells 11, 11 adjacent to each other in the Y-axis direction. As a result, the positive electrode terminals 18P and the negative electrode terminals 18N are arranged alternately in the Y-axis direction in which the multiple battery cells 11 are stacked. Between the battery cells 11, 11 adjacent to each other in the Y-axis direction, the positive electrode terminals 18P and the negative electrode terminals 18N arranged in the Y-axis direction are connected to each other by a bus bar (not shown). The multiple battery cells 11 are electrically connected to each other in series.

[0036] A cell stack 10 is composed of multiple battery cells 11 stacked in the Y-axis direction. The cell stack 10 has a rectangular parallelepiped shape. As a typical example, the length of the cell stack 10 in the Y-axis direction is greater than the length of the cell stack 10 in the Z-axis direction, and is greater than the length of the cell stack 10 in the X-axis direction.

[0037] The battery pack 100 further includes a case body 21. The case body 21 is a box having a rectangular parallelepiped appearance as a whole. The case body 21 is made of metal. The case body 21 is made of iron (steel plate), for example. The case body 21 includes a case bottom 22, case sides 23, and a case top 24.

[0038] The case bottom 22 is disposed at the bottom of the case body 21. The case bottom 22 is made of a plate material extending in the X-axis-Y plane, with the thickness direction being in the Z-axis direction. The case side 23 rises upward from the periphery of the case bottom 22, and forms an opening at its tip. The case top 24 is disposed opposite the case bottom 22 in the Z-axis direction. The case top 24 closes the opening formed by the case side 23. The case top 24 is fastened to the case side 23 using bolts or the like.

[0039] The case body 21 defines an internal space 70. A plurality of battery cells 11 (cell stack 10) are housed in the internal space 70. The plurality of battery cells 11 are placed on the case bottom 22. A heat transfer member may be interposed between the bottom surface 16 of the battery cell 11 and the case bottom 22. The heat transfer member may be made of an adhesive material (adhesive) or a non-adhesive material. The plurality of battery cells 11 are restrained by the case side parts 23 at both ends in the Y-axis direction. The case side parts 23 apply a restraining force (compressive force) in the Y-axis direction to the plurality of battery cells 11.

[0040] The internal space 70 is a space where no forced airflow is formed. The forced airflow means airflow caused by a blower. Natural convection of air caused by heat generation from the battery cells 11 does not correspond to a forced airflow.

[0041] The internal space 70 is a sealed space. The internal space 70 is isolated from the external space so that air flow between the internal space 70 and a space (external space) outside the internal space 70 is restricted. Even if the case body 21 has holes for leading various wiring from the internal space 70 to the external space, the holes are provided with connectors or the like for maintaining the sealing of the internal space 70.

[0042] The battery pack 100 further includes a duct body 31 and a blower 41 (41A, 41B).

[0043] The duct body 31 is made of metal. The duct body 31 may be made of the same type of metal as the case body 21, or may be made of a different type of metal from the case body 21. In the latter case, the thermal conductivity of the metal forming the duct body 31 may be greater than the thermal conductivity of the metal forming the case body 21. The duct body 31 is made of aluminum, for example.

[0044] The duct body 31 is disposed outside (in the external space) of the case body 21. The duct body 31 is connected to the case body 21. The duct body 31 is connected to the case bottom 22 of the case body 21. The duct body 31 may be fastened to the case body 21 using bolts or the like, or may be joined to the case body using an adhesive. A heat-conductive resin sheet or the like may be interposed between the case body 21 and the duct body 31.

[0045] The duct body 31 defines an air passage 80 through which air can flow. The air passage 80 is not in communication with the internal space 70. The duct body 31 (air passage 80) extends in the Y-axis direction, which is the stacking direction of the battery cells 11.

[0046] The path of the ventilation passage 80 is not particularly limited. For example, the ventilation passage 80 may meander so that it extends in an alternating manner in the +Y axis direction and the -Y axis direction, or may extend in the X axis direction perpendicular to the stacking direction of the battery cells 11. Furthermore, the duct body 31 may define a plurality of ventilation passages 80 that extend independently of one another.

[0047] The duct body 31 has openings 32 (32A, 32B). The openings 32 open the ventilation passage 80 toward the outside space. The openings 32A (first opening) are open at an end of the duct body 31 in the +Y-axis direction. The openings 32B (second opening) are open at an end of the duct body 31 in the -Y-axis direction. The ventilation passage 80 extends in one direction between the openings 32A and 32B.

[0048] In a top view, the duct body 31 is provided so as not to protrude from the peripheral edge of the case bottom 22. When the lengths of the case bottom 22 and the duct body 31 in the X-axis direction are Ha and Hb, respectively, and the lengths of the case bottom 22 and the duct body 31 in the Y-axis direction are La and Lb, respectively, the relationships Hb≦Ha and Lb≦La are satisfied. With this configuration, it is possible to prevent the size of the battery pack 100 in a top view from becoming larger due to the installation of the duct body 31.

[0049] Particularly in this embodiment, the duct body 31 is provided so that the side surface of the case body 21 at the case side portion 23 is flush with the opening surface formed by the openings 32 (32A, 32B) of the duct body 31. With this configuration, it is possible to maximize the range in the Y-axis direction where the ventilation passage 80 through which air flows and the duct body 31 overlap vertically.

[0050] The duct body 31 is made of an extruded material made of metal (aluminum). The duct body 31 is manufactured by extrusion molding. When the duct body 31 is cut along the X-axis-Z-axis plane, the cross-sectional shape of the duct body 31 is the same at all cutting positions in the Y-axis direction. With this configuration, the duct body 31 with excellent thermal conductivity can be easily manufactured.

[0051] The blower 41 is configured to circulate air through the duct body 31. The blower 41 has a fan 42 and a motor (not shown). The fan 42 is rotated by receiving rotation from the motor.

[0052] The fan 42 of the blower 41A is disposed opposite the opening surface formed by the opening 32A. The fan 42 of the blower 41B is disposed opposite the opening surface formed by the opening 32B. The fan 42 is provided inside the duct body 31 (ventilation passage 80). The fan 42 of the blower 41A may be disposed immediately below the battery cell 11 disposed at the end in the +Y-axis direction among the multiple battery cells 11. The fan 42 of the blower 41B may be disposed immediately below the battery cell 11 disposed at the end in the -Y-axis direction among the multiple battery cells 11. By driving the fans 42 of the blower 41A and the blower 41B to rotate, an air flow is formed in the ventilation passage 80, which flows from the external space through the opening 32B, flows in the +Y-axis direction, and flows out to the external space through the opening 32A.

[0053] It should be noted that duct body 31 may be provided with only one of blower 41A and blower 41B.

[0054] In this embodiment, heat generated in the multiple battery cells 11 is dissipated through air flowing from the case body 21 through the duct body 31, thereby providing a cooling function for the battery cells 11. In this case, by arranging the duct body 31 on the outside of the case body 21 and making the internal space 70 of the case body 21 that houses the multiple battery cells 11 a space in which no forced air flow is formed, it becomes unnecessary to provide a ventilation hole in the case body 21. As a result, water or dust will not enter the internal space 70 through the ventilation hole, and the waterproof and dustproof functions of the battery pack 100 can be sufficiently ensured.

[0055] Moreover, the fan 42 of the air blowing device 41 is provided inside the duct body 31 (air passage 80). With this configuration, the air blowing device 41 does not need to have a case for accommodating the fan 42, so that the air blowing device 41 can be simply configured.

[0056] FIG. 4 is a cross-sectional view showing a first modified example of the battery pack in FIG. 1. Referring to FIG. 4, in this modified example, duct body 31 has openings 32 (32A, 32B, 32C). Opening 32C (third opening) opens between the end of duct body 31 in the +Y-axis direction and the end of duct body 31 in the -Y-axis direction. The distance between openings 32A and 32C in the Y-axis direction is equal to the distance between openings 32B and 32C in the Y-axis direction. Opening 32C is formed of a through hole penetrating the wall of duct body 31 in the Z-axis direction. Opening 32C may be formed of a through hole penetrating the wall of duct body 31 in the X-axis direction.

[0057] The battery pack has a blower 41 (41C). The fan 42 of the blower 41C is disposed facing the opening surface formed by the opening 32C. The fan 42 of the blower 41C is provided inside the duct body 31 (ventilation passage 80). When the fan 42 of the blower 41C is rotationally driven, air flows from the external space into the ventilation passage 80 through the opening 32C. In the ventilation passage 80, an air flow that flows from the opening 32C in the +Y-axis direction and flows out to the external space through the opening 32A, and an air flow that flows from the opening 32C in the -Y-axis direction and flows out to the external space through the opening 32B are formed.

[0058] Heat from the multiple battery cells 11 is gradually transferred to the air flowing through the ventilation passage 80. As a result, the temperature of the air downstream of the air flow in the ventilation passage 80 becomes higher than the temperature of the air upstream, causing variations in cooling efficiency among the multiple battery cells 11. In addition, heat dissipation from the multiple battery cells 11 via the case body 21 proceeds more efficiently from the battery cells 11 arranged at the ends of the stacking direction than from the battery cells 11 arranged in the middle of the stacking direction, causing variations in cooling efficiency among the multiple battery cells 11.

[0059] In this modified example, air flows through the ventilation passages 80 from the middle to both ends in the stacking direction of the battery cells 11, so that variation in cooling efficiency between the multiple battery cells 11 can be suppressed.

[0060] Fig. 5 is a cross-sectional view showing a second modified example of the battery pack in Fig. 1. Referring to Fig. 4, in this modified example, a fan 42 is provided outside the duct body 31.

[0061] The blower 41 has a fan 42, a motor (not shown), and a fan case 43. The fan 42 is housed in the fan case 43. The fan case 43 has a cylindrical shape extending in the Y-axis direction. The fan case 43 is connected to the duct body 31. The fan case 43 of the blower 41A is connected to an end of the duct body 31 in the +Y-axis direction. The fan case 43 of the blower 41B is connected to an end of the duct body 31 in the -Y-axis direction.

[0062] Fig. 6 is a cross-sectional view showing a third modified example of the battery pack in Fig. 1. Referring to Fig. 6, in this modified example, the battery pack has a duct body 31 (31A, 31B). The duct body 31 is connected to the case side parts 23 of the case body 21. The duct body 31A and the duct body 31B are each connected to a pair of case side parts 23 facing each other in the Y-axis direction. The duct body 31 defines a ventilation passage 80 extending in the X-axis direction.

[0063] There is no particular limitation on the location where the duct body 31 is connected to the case body 21. For example, the duct body 31 may be provided so as to go around a pair of case side parts 23 facing each other in the Y-axis direction and a pair of case side parts 23 facing each other in the X-axis direction, or may be provided on both the case bottom part 22 and the case side parts 23 of the case body 21.

[0064] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0065] 10 cell stack, 11 battery cell, 12 exterior body, 13 first side, 14 second side, 15 top surface, 16 bottom surface, 17 gas exhaust valve, 18 electrode terminal, 18N negative terminal, 18P positive terminal, 21 case body, 22 case bottom, 23 case side, 24 case top, 31, 31A, 31B duct body, 32, 32A, 32B, 32C opening, 41, 41A, 41B, 41C blower, 42 fan, 43 fan case, 70 internal space, 80 ventilation passage, 100 battery pack.

Claims

1. A plurality of stacked battery cells; a case body that defines an internal space in which no forced air flow is formed and that houses a plurality of the battery cells in the internal space; a duct body disposed outside the case body and connected to the case body; a blower for circulating air through the duct body, The duct body is provided with an opening for opening the air flow path to the outside, The air blowing device has a fan disposed opposite to an opening surface defined by the opening, The duct body extends in one direction, the opening includes a first opening and a second opening that open at one end and the other end of the duct body in the one direction, respectively, and a third opening that opens between the one end and the other end of the duct body in the one direction, The fan is disposed opposite an opening surface defined by the third opening.

2. the case body has a bottom portion on which the plurality of battery cells are placed and a side portion rising from the bottom portion, The battery pack according to claim 1 , wherein the duct body is connected to at least one of the bottom portion and the side portion.

3. The duct body is connected to the bottom portion, The battery pack according to claim 2 , wherein the duct body is provided so as not to protrude from a peripheral edge portion of the case body in a top view.

4. The battery pack according to claim 1 , wherein the fan is disposed inside the duct body.

5. The battery pack according to claim 1 , wherein the plurality of battery cells are stacked in the one direction.

6. The battery pack according to claim 1 , wherein the duct body is made of an extruded metal material.

7. A plurality of stacked battery cells; a case body that defines an internal space in which no forced air flow is formed and that houses a plurality of the battery cells in the internal space; a duct body disposed outside the case body and connected to the case body; a blower for circulating air through the duct body, the case body has a bottom on which the plurality of battery cells are placed, The duct body is connected to the bottom portion, The duct body is provided so as not to protrude from the peripheral edge portion of the case body when viewed from above, The duct body extends in one direction, the duct body is provided with a first opening and a second opening that open at one end and the other end of the duct body in the one direction, respectively, and open an air flow path to the outside; the blower device has a fan disposed opposite to an opening surface defined by at least one of the first opening and the second opening, The fan is disposed inside the duct body.

Images