Battery pack

Abstract

To provide a battery pack capable of suppressing damage to a power storage device while controlling the displacement of the power storage device.SOLUTION: The battery pack has a configuration in which a power storage device is accommodated in a case composed of a lower case and an upper case. The lower case and the upper case oppose each other in a first direction. In a second direction perpendicular to the first direction, a filling member fills a space between the lower case and the power storage device. In the second direction, a buffer member is provided between the filling member and the power storage device. The buffer member has a Young's modulus smaller than that of the filling member.SELECTED DRAWING: Figure 2

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses a battery module (laminated body) including a side regulation portion that suppresses displacement of battery cells in the horizontal direction.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Since the space between the battery module and the side wall is filled by the side regulation portion, the horizontal movement of the battery module can be restricted. However, depending on the magnitude of the inertial force, the battery module may be damaged.

[0005] The present invention has been made in view of the above problems, and an object thereof is to provide a battery pack capable of restricting displacement of a power storage device and suppressing damage to the power storage device.

Means for Solving the Problems

[0006] In order to solve the above-described problems and achieve the object, a battery pack according to the present invention is a battery pack in which a power storage device is housed in a case composed of a lower case and an upper case, the lower case and the upper case face each other in a first direction, in a second direction orthogonal to the first direction, a filling member is filled between the lower case and the power storage device, a buffer member is provided between the filling member and the power storage device in the second direction, and the buffer member is characterized in that the Young's modulus is smaller than that of the filling member.

[0007] As a result, the battery pack according to the present invention can suppress damage to the power storage device while restricting displacement of the power storage device.

[0008] Further, in the above, the power storage device may have a plurality of battery modules stacked in the first direction, and the buffer member may be positioned so as to overlap the battery module when viewed from the second direction.

[0009] As a result, since the buffer member is disposed at a position overlapping the battery module when viewed from the second direction with respect to the battery module that is a weak part against impact, damage to the power storage device (battery module) can be more suitably suppressed.

[0010] Further, in the above, the buffer member may have a communication hole communicating with the surplus space in the case.

[0011] As a result, through the communication hole provided in the buffer member, the ejecta from the power storage device can be more suitably discharged to the surplus space in the case.

[0012] Further, in the above, the plurality of battery modules stacked in the first direction included in the power storage device each include a safety valve, and the buffer member may be dissolved by the ejecta ejected from the safety valve or penetrated by the pressure of the ejecta.

[0013] As a result, by dissolving or penetrating the buffer member by the ejecta ejected from the safety valve of the battery module, the buffer member can be used as a discharge path for the ejecta.

Advantages of the Invention

[0014] The battery pack according to the present invention has an effect that it can suppress damage to the power storage device while restricting displacement of the power storage device.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

MODE FOR CARRYING OUT THE INVENTION

[0016] (Embodiment 1) Hereinafter, Embodiment 1 of the battery pack according to the present invention will be described. Note that the present invention is not limited by this embodiment.

[0017] FIG. 1 is a cross-sectional view showing a schematic configuration when the battery pack 1 according to Embodiment 1 is viewed from above. FIG. 2 is a view showing an A-A cross-section of the battery pack shown in FIG. 1.

[0018] In Embodiment 1, the battery pack 1 is mounted on an electric vehicle and is, for example, a power supply that supplies power to a motor that is a drive source of the electric vehicle. The battery pack 1 according to Embodiment 1 includes a case 3 composed of an upper case 31 and a lower case 32. The battery stack 2, which is a power storage device, is housed in the case 3.

[0019] The battery stack 2 is a laminate formed by alternately stacking a plurality of battery modules 21a, 21b, 21c, 21d and a plurality of current-carrying members 22a, 22b, 22c vertically between a lower current-collecting member 23a and an upper current-collecting member 23b in the height direction which is the first direction of the battery pack 1. In the battery pack 1 according to Embodiment 1, the height direction is the same as the stacking direction of the plurality of battery modules 21a, 21b, 21c, 21d.

[0020] The upper case 31 and the lower case 32 face each other in the height direction. The upper case 31 and the lower case 32 each have a flange-shaped upper-side joint portion 310 and a lower-side joint portion 320 for joining each other at their respective peripheries. In the case 3, the upper-side joint portion 310 and the lower-side joint portion 320 are joined to form a case joint portion 300. The lower-side joint portion 320 is positioned so as to overlap the battery stack 2 when viewed from the vehicle width direction which is the second direction orthogonal to the height direction. Note that the second direction orthogonal to the height direction which is the first direction is not limited to the vehicle width direction, and for example, the vehicle longitudinal direction (see FIG. 1) orthogonal to the height direction and the vehicle width direction is also included. Further, in the battery pack 1 according to Embodiment 1, the first direction is the vertical direction and the second direction is the horizontal direction.

[0021] The case 3 is filled with a filling member 4 that can fill the space between the battery stack 2 and the lower case 32 without a gap so as to surround the battery stack 2. Further, the filling member 4 is filled up to the upper case 31 side in the height direction from the lower-side joint portion 320. The upper end surface 400 of the filling member 4 is positioned at substantially the same height as the upper end surface 200 of the battery stack 2 in the height direction. Note that in the battery pack 1 according to Embodiment 1, the upper surface of the upper current-collecting member 23b forms the upper end surface 200 of the battery stack 2. The filling member 4 functions as a displacement restricting portion that restricts displacement of the battery stack 2 in the lateral direction (the vehicle width direction and the vehicle longitudinal direction). As the filling member 4, for example, a material that is initially liquid and hardens over time can be used.

[0022] Also, as shown in FIG. 1, in the second direction, between the side surface of the battery stack 2 and the filling member 4, plate-shaped buffer members 5A, 5B, 5C, 5D are provided. Specifically, in the vehicle width direction, a pair of buffer members 5A, 5B are provided so as to face each other with the battery stack 2 interposed therebetween. The buffer members 5A, 5B are respectively arranged so as to be in contact with the side surfaces of the battery stack 2 in the vehicle width direction. The buffer members 5A, 5B have a shorter width in the vehicle longitudinal direction than the width of the battery stack 2. Also, in the vehicle longitudinal direction, a pair of buffer members 5C, 5D are provided so as to face each other with the battery stack 2 interposed therebetween. The buffer members 5C, 5D are respectively arranged so as to be in contact with the side surfaces of the battery stack 2 in the vehicle longitudinal direction. The buffer members 5C, 5D have a shorter width in the vehicle width direction than the width of the battery stack 2. In the following description, when the buffer members 5A, 5B, 5C, 5D are not particularly distinguished, they are simply referred to as the buffer member 5. The buffer member 5 is arranged at at least one location on the outer periphery (the second direction) of the battery stack 2.

[0023] Next, the battery pack 1 according to Embodiment 1 will be described using FIG. 2 as an example of the buffer member 5A. Note that even if there are differences such as the difference between the vehicle width direction and the vehicle longitudinal direction as the second direction, basically the other buffer members 5B, 5C, 5D are the same as the buffer member 5A, so their descriptions will be omitted.

[0024] As shown in FIG. 2, the upper end surface 500 of the buffer member 5A is located at substantially the same height as the upper end surface 200 of the battery stack 2 and the upper end surface 400 of the filling member 4 in the height direction, and is exposed in the upper surplus space 33 formed between the battery stack 2 and the upper case 31 in the case 3.

[0025] Also, the buffer member 5A has a smaller Young's modulus than the filling member 4. Thereby, for example, when the battery stack 2 tries to slide in the second direction (horizontal direction) during a vehicle collision, while the filling member 4 restricts the displacement of the battery stack 2 in the second direction (horizontal direction), the buffer member 5A absorbs energy (inertial force), so that it is possible to suppress the battery stack 2 from being damaged.

[0026] Further, the buffer member 5A is positioned so as to overlap the battery stack 2 when viewed from the second direction (the vehicle width direction), and is in contact with all the battery modules 21a, 21b, 21c, 21d of the battery stack 2. Thereby, since the buffer member 5A is disposed at a position overlapping when viewed from the second direction with respect to the battery modules 21a, 21b, 21c, 21d which are weak against impacts, it is possible to more preferably suppress damage to the battery stack 2 (battery module 21).

[0027] The buffer member 5 may itself have air permeability, or may be a material that melts by the heat of the ejected material ejected from the safety valve provided in the battery module 21 or penetrates by the pressure of the ejected material. Thereby, in the battery pack 1 according to Embodiment 1, it is possible to discharge the ejected material (ejected gas) to the upper surplus space 33 in the case 3 as a discharge path for the ejected material (ejected gas) ejected from the safety valve of the battery module 21. Therefore, an excessive increase in the internal pressure of the battery module 21 can be suppressed, and the safety can be improved.

[0028] Further, in the battery pack 1 according to Embodiment 1, by providing the buffer member 5, the amount of the filling member 4 used can be reduced, so that an increase in the temperature of the battery module 21 due to heat generation caused by the curing of the filling member 4 can be suppressed. Thereby, it is possible to achieve both protection of the battery module 21 and shortening of the curing time of the filling member 4, and it is possible to reduce the cost and mass.

[0029] (Embodiment 2) Hereinafter, Embodiment 2 of the battery pack according to the present invention will be described. Note that descriptions of the same configurations as those in Embodiment 1 in this embodiment will be omitted as appropriate.

[0030] FIG. 3 is a partial cross-sectional view showing a schematic configuration of the battery pack 1 according to Embodiment 2.

[0031] In the battery pack 1 according to Embodiment 2, an opening 50a is formed in the upper end surface 500 of the buffer member 5A, and the buffer member 5A has a communication hole 50 that communicates with the upper surplus space 33 in the case 3 through the opening 50a. The communication hole 50 is formed inside the buffer member 5 so that the ejecta (ejected gas) ejected from the safety valves provided in the battery modules 21a, 21b, 21c, and 21d can pass through and be discharged from the opening 50a to the upper surplus space 33 in the case 3.

[0032] Accordingly, in the battery pack 1 according to Embodiment 2, the communication hole 50 of the buffer member 5 can be used as a discharge path for the ejecta (ejected gas) ejected from the safety valves of the battery modules 21a, 21b, 21c, and 21d, and the ejecta (ejected gas) can be discharged to the upper surplus space 33 in the case 3.

[0033] (Embodiment 3) Hereinafter, Embodiment 3 of the battery pack according to the present invention will be described. In this embodiment, descriptions of the same configurations as those in Embodiment 1 will be omitted as appropriate.

[0034] FIG. 4 is a partial cross-sectional view showing a schematic configuration of the battery pack 1 according to Embodiment 3.

[0035] In the battery pack 1 according to Embodiment 3, as shown in FIG. 4, a plate-shaped partition wall 6 that extends upward in the height direction from the bottom surface portion 321 of the lower case 32 is provided at a predetermined interval from the battery stack 2 so as to surround the battery stack 2. The upper end surface 600 of the partition wall 6 protrudes toward the upper case 31 side in the height direction from the lower side joint portion 320. Further, in the battery pack 1 according to Embodiment 3, in the height direction, the height of the upper end surface (apex) 600 of the partition wall 6 is configured to be higher than the height of the upper end surface (apex) 200 of the battery stack 2 by a distance d. In the battery pack 1 according to Embodiment 3, the upper surface of the upper current collector member 23b forms the upper end surface 200 of the battery stack 2.

[0036] A filling member 4 capable of filling the gap between the partition wall 6 and the battery stack 2 without any gap is filled between the partition wall 6 and the battery stack 2. Also, the filling member 4 fills up to the upper case 31 side in the height direction from the lower side joint portion 320. The upper end surface 400 of the filling member 4 is located at substantially the same height as the upper end surface 200 of the battery stack 2 in the height direction.

[0037] The buffer member 5A has an L-shaped configuration in which the lower portion in the height direction protrudes toward the partition wall 6 side in the second direction (the vehicle width direction in FIG. 4). The lower portion of the buffer member 5A extends to the inside of the through hole 60 provided in the lower portion of the partition wall 6. The upper end surface 500 of the buffer member 5A is covered by the filling member 4 in the height direction and does not have an opening that opens into the upper surplus space 33 in the case 3. On the other hand, an opening 50b is formed in the lower portion of the buffer member 5A, which opens into the lateral surplus space 34 formed between the partition wall 6 and the lower case 32 in the vehicle width direction through the through hole 60 of the partition wall 6.

[0038] In the battery pack 1 according to Embodiment 3, the communication hole 50 of the buffer member 5A is formed inside the buffer member 5A so that the ejecta (ejected gas) ejected from the safety valves provided in the battery modules 21a, 21b, 21c, 21d can pass through and be discharged from the opening 50b to the lateral surplus space 34 in the case 3. Thereby, it is possible to suppress the high-temperature ejecta (ejected gas) ejected from any of the safety valves of the battery modules 21a, 21b, 21c, 21d from ejecting directly above the battery stack 2 through the communication hole 50, and thus it is possible to suppress the temperature rise of the upper case 31. Therefore, it is possible to reduce the heat insulating material of the floor above the upper case 31 in the vehicle, and while ensuring the safety of the vehicle occupants, it is possible to reduce the number of parts.

[0039] (Embodiment 4) Hereinafter, Embodiment 4 of the battery pack according to the present invention will be described. Note that, for the same configurations as those in Embodiment 1 in this embodiment, the description will be omitted as appropriate.

[0040] FIG. 5 is a cross-sectional view showing a schematic configuration when the battery pack 1 according to Embodiment 4 is viewed from above. FIG. 6 is a view showing a B-B cross-section of the battery pack 1 shown in FIG. 5. Note that since the C-C cross-section of the battery pack 1 shown in FIG. 5 is the same as the A-A cross-section of the battery pack 1 according to Embodiment 1 shown in FIG. 2, illustration and description thereof are omitted.

[0041] In the battery pack 1 according to Embodiment 4, as shown in FIG. 5, a buffer member 5 is arranged over the entire circumference (all sides) of the battery stack 2 (battery module 21) in a top view. Further, in the battery pack 1 according to Embodiment 4, as shown in FIG. 6, the buffer member 5 is divided into buffer members 5a, 5b, 5c, 5d in the height direction. The buffer members 5a, 5b, 5c, 5d are in contact with the side surfaces of the battery modules 21a, 21b, 21c, 21d in the vehicle width direction, respectively. In the height direction, the heights (thicknesses) of the buffer members 5a, 5b, 5c, 5d are each set to be equal to or greater than the heights (thicknesses) of the corresponding battery modules 21a, 21b, 21c, 21d.

[0042] Note that in the battery pack 1 according to Embodiment 4, on at least one of the four side surfaces of the battery stack 2 in the vehicle width direction and the vehicle longitudinal direction, as in the A-A cross-section in FIG. 5 (see FIG. 2), the buffer member 5 is continuous in the height direction and is in contact with the battery modules 21a, 21b, 21c, 21d.

[0043] In the battery pack 1 according to Embodiment 4, since the entire side surfaces of the battery modules 21a, 21b, 21c, 21d are covered with the buffer member 5, heat generated due to the curing of the filling member 4 is less likely to be transmitted to the battery modules 21a, 21b, 21c, 21d. Therefore, in the battery pack 1 according to Embodiment 4, a filling member 4 that cures faster can be selected, so that the time required for manufacturing the battery pack 1 can be shortened.

Description of Reference Numerals

[0044] 1 Battery pack 2 Battery stack 3 Case 4 Filling member 5, 5A, 5B, 5C, 5D, 5a, 5b, 5c, 5d buffer members 6 partition wall 21, 21a, 21b, 21c, 21d battery modules 22a, 22b, 22c current-carrying members 23a lower current-collecting member 23b upper current-collecting member 31 upper case 32 lower case 33 upper surplus space 34 side surplus space 50 communication hole 50a, 50b openings 200, 400, 500, 600 upper end faces 300 case joint 310 upper side joint 320 lower side joint 321 bottom face

Claims

1. A battery pack in which a power storage device is housed in a case composed of a lower case and an upper case, wherein the lower case and the upper case face each other in a first direction, in a second direction orthogonal to the first direction, a filling member is filled between the lower case and the power storage device, in the second direction, a buffer member is provided between the filling member and the power storage device, the buffer member having a smaller Young's modulus than the filling member, characterized in that it is a battery pack.

2. The power storage device has a plurality of battery modules stacked in the first direction, the buffer member being positioned so as to overlap the battery module when viewed from the second direction, characterized in that it is the battery pack according to Claim 1.

3. The buffer member having a communication hole communicating with the surplus space in the case, characterized in that it is the battery pack according to Claim 1 or 2.

4. The plurality of battery modules stacked in the first direction that the power storage device has each have a safety valve, the buffer member being dissolved by the ejected matter ejected from the safety valve or penetrated by the pressure of the ejected matter, characterized in that it is the battery pack according to Claim 1 or 2.

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