JP2014149992A - Battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve heat radiation performance of a battery module.SOLUTION: A battery pack 30 includes a counter weight 31. The counter weight 31 includes a weight body 32 extending in a vertical direction. Plate members 38, 39, 40 functioning as well-thermal conduction parts are provided on a surface 32a of the weight body 32 when viewed in a thickness direction. A battery module 50 is provided contacting with the plate members 38, 39, 40 and are placed on a bottom part 33, a first protruding part 34, and a second protruding part 35 which protrude from the weight body 32.

Description

  The present invention relates to a battery pack in which a battery module is installed on a body to be installed.

  As a battery pack which has a battery module, the secondary battery apparatus of patent document 1 is mentioned, for example. The secondary battery device described in Patent Document 1 includes a plurality of battery stack assemblies. The battery stack assembly includes a floor plate, a back plate erected from the floor plate, and a base plate fixed on the floor plate. A battery module is placed on the base plate. The battery module is in contact with the back plate. A side plate is erected on the edge of the base plate so as to sandwich the battery module. A base plate is provided on the battery module via a packing, and the battery modules are stacked on the base plate by placing the battery modules on the base plate.

JP 2011-54353 A

By the way, when the temperature of a battery module rises, there exists a possibility that the lifetime of a battery module may become short, Therefore It is desired to improve the heat dissipation of a battery module.
The objective of this invention is providing the battery pack which can improve the heat dissipation of a battery module.

  A battery pack that solves the above-described problem includes an installed body that includes a standing portion that is erected in the vertical direction, and a mounting portion that projects from the erected portion in a direction that intersects the vertical direction, and a plurality of battery cells. And the battery module is in contact with the standing portion and placed on the mounting portion, and the standing portion is at least part of the portion in contact with the battery module, The gist of the present invention is to have a good heat conducting portion made of a material having good thermal conductivity as compared with a portion of the mounted body that does not contact the battery module.

  According to this, when the battery module generates heat due to charging / discharging of the battery cells, this heat is conducted to the object to be installed. At this time, at least a part of the portion of the standing portion that comes into contact with the battery module becomes a good heat conducting portion, so that the heat generated by the battery module is easily diffused to the object to be installed. For this reason, the heat dissipation of a battery module can be improved. In addition, materials with good thermal conductivity tend to be more fragile. If the battery module is fixed to the good heat conduction part by screwing or the like, the good heat conduction part may not be able to support the load of the battery module. is there. In this invention, the mounting part which protrudes from a standing part is provided, and a battery module can be supported also in a mounting part by mounting a battery module in this mounting part. For this reason, the load applied to the good heat conduction part of the standing part is reduced. Therefore, it is possible to prevent the battery module from dropping from the standing portion while improving the heat dissipation of the battery module.

About the said battery pack, it is preferable that the said good heat conductive part consists of aluminum or copper.
According to this, the heat conductivity of the good heat conduction part can be suitably improved.

In the battery pack, it is preferable that the object to be installed includes a counterweight mounted on an industrial vehicle, and the standing part is erected from an iron bottom part extending in a horizontal direction.
According to this, a to-be-installed body has an iron bottom part extended in a horizontal direction. Since a material having good thermal conductivity is lightweight, if a part of the standing portion is a good heat conducting portion, the weight of the standing portion is reduced and the function as a counterweight may be insufficient. By providing a bottom made of iron, the center of gravity can be lowered while securing the weight necessary to function as a counterweight, so even if a part of the standing part is a good heat conduction part, It can be used as a counterweight.

  About the said battery pack, the said to-be-installed body has two or more said mounting parts, and the said good heat conduction part which the said battery module is mounted in each of the said mounting parts, and is located in the perpendicular direction upper volume. Is preferably large.

  According to this, since the heat generated by the battery module moves in the upward direction in the vertical direction, the battery module located in the upward direction in the vertical direction is easily heated by this heat. By increasing the volume of the good heat conduction part in contact with the battery module located in the upper vertical direction, the heat dissipation of the battery module located in the upper vertical direction can be improved, and only the temperature of some battery modules is excessive. It is suppressed to rise.

  According to the present invention, the heat dissipation of the battery module can be improved.

The schematic side view which shows the forklift of embodiment. The perspective view which shows the battery pack of embodiment. Sectional drawing which shows the battery pack of embodiment. The perspective view which shows the battery module of embodiment. The perspective view which shows the square battery, battery holder, and end plate of embodiment. Sectional drawing which shows the battery module of embodiment.

  Hereinafter, an embodiment in which the battery pack is embodied as a battery pack mounted on a forklift will be described. In the following description, “front”, “rear”, “left”, “right”, “upper”, and “lower” are “front”, “rear”, and “left” when the forklift driver is facing the front of the forklift. ”,“ Right ”,“ upper ”, and“ lower ”.

  As shown in FIG. 1, drive wheels 12 are provided at the front lower part of a vehicle body 11 of a forklift 10 as an industrial vehicle, and steering wheels 13 are provided at a rear lower part of the vehicle body 11. In addition, a cargo handling device is provided at the front portion of the vehicle body 11. The mast 14 constituting the cargo handling apparatus is erected on the front portion of the vehicle body 11, and the mast 14 is provided with a pair of left and right forks 16 via a lift bracket 15. The fork 16 is lifted and lowered together with the lift bracket 15 by driving a lift cylinder 17 connected to the mast 14. Further, the fork 16 is tilted together with the mast 14 by driving a tilt cylinder 18 connected to the mast 14. A load 19 is mounted on the fork 16. The vehicle body 11 is equipped with a traveling motor M1 as a drive source for the drive wheels 12 and a cargo handling motor M2 as a drive source for the fork 16.

  A cab 20 is provided in the center of the vehicle body 11. The cab 20 is provided with a driving seat 21 on which an operator (driver) can sit. A handle 22 is provided in front of the driving seat 21. A battery pack 30 is mounted below the cab 20. Hereinafter, the battery pack 30 will be described in detail.

  As shown in FIGS. 2 and 3, the battery pack 30 includes a counterweight 31 as an installation body for balancing the load 19 mounted on the fork 16. The counterweight 31 includes a main body 37 and plate members 38, 39, and 40 provided on the main body 37. The main body 37 has a rectangular parallelepiped bottom 33. The bottom 33 extends in the horizontal direction. From the one end 33a in the short side direction of the bottom 33, a rectangular flat plate-like weight body 32 is erected in the thickness direction of the bottom 33. In other words, the bottom 33 is erected from the proximal end of the weight body 32 in the thickness direction of the weight body 32. The weight main body 32 has a rectangular plate shape. A first protrusion 34, a second protrusion 35, and a third protrusion that protrude in the thickness direction of the weight body 32 are formed on a surface 32 a in the thickness direction of the weight body 32 (the surface on which the bottom 33 is provided). 36 are provided in the transverse direction of the weight main body 32 at intervals. Each protrusion 34, 35, 36 protrudes from the weight body 32 in a direction intersecting with the vertical direction.

  Each protrusion 34, 35, 36 has a rectangular flat plate shape and extends over the entire length of the weight body 32. The longitudinal direction of each protrusion 34, 35, 36 coincides with the longitudinal direction of the weight body 32, and the short direction coincides with the protrusion direction from the surface 32a. The main body 37 includes a bottom 33, a weight main body 32, and protrusions 34, 35, and 36. The bottom 33, the weight main body 32, and the protrusions 34, 35, and 36 are integrally formed by a manufacturing method such as casting. In the present embodiment, the bottom 33, the weight body 32, and the protrusions 34, 35, and 36 are made of iron.

  On the surface 32a of the weight body 32, plate members 38, 39, and 40 having a rectangular flat plate shape are provided. Specifically, a first plate member 38 is provided between the bottom 33 and the first protrusion 34 on the surface 32a. The first plate member 38 has the same dimension in the short direction as the dimension between the bottom 33 and the first protrusion 34. Further, a second plate member 39 is provided between the first protrusion 34 and the second protrusion 35 on the surface 32a. The dimension in the short direction of the second plate member 39 is the same as the dimension between the first protrusion 34 and the second protrusion. On the surface 32a, a third plate member 40 is provided between the second protrusion 35 and the third protrusion 36. The dimension in the short direction of the third plate member 40 is the same as the dimension between the second protrusion 35 and the third protrusion 36. In addition, the dimension of the transversal direction of each plate member 38, 39, 40 is the same dimension. Each plate member 38, 39, 40 extends over the entire length of the weight body 32.

  The third plate member 40 is thicker than the second plate member 39, and the second plate member 39 is thicker than the first plate member 38. That is, the plate members 38, 39, and 40 are thicker in the order of the third plate member 40> the second plate member 39> the first plate member 38, and the plate members 38, 39 provided in the upper vertical direction. , About 40 thicker. Since each of the plate members 38, 39, and 40 has the same dimension in the short direction and the same dimension in the longitudinal direction, the volume of the thickest third plate member 40 is the largest, and the volume of the second plate member 39 is Is next to the third plate member 40. The volume of the first plate member 38 is the smallest. Each plate member 38, 39, 40 is manufactured from aluminum. Aluminum has better thermal conductivity than iron, and in this embodiment, the plate members 38, 39, and 40 are good heat conducting portions. The weight main body 32 and the plate members 38, 39, and 40 constitute a standing portion.

  As shown in FIG. 2, in the short direction of the bottom portion 33, the other end 33 b in the short side opposite to the short side one end 33 a where the weight main body 32 is provided is reversely provided apart from the weight main body 32. A U-shaped frame 41 is erected from the bottom 33. The frame 41 includes a first pillar portion 43 and a second pillar portion 44 erected from two corners of the other end 33b in the lateral direction on the upper surface of the bottom portion 33, and the first pillar portion 43 and the second pillar portion 44. And a base 42 that connects the upper end of the column 44 (the end opposite to the end joined to the bottom 33). In other words, the battery pack 30 has a front opening 30 a surrounded by the bottom 33 and the frame 41 on the other end 33 b side of the bottom 33. In the battery pack 30, the front opening 30a is closed by a lid member 46 having a rectangular plate shape.

  The length of each pillar portion 43, 44 in the standing direction (the length in the longitudinal direction of each pillar portion 43, 44) is opposite from the top surface of the bottom portion 33 to the distal end of the weight body 32 (the base end of the weight body 32). The top plate 47 is supported on the upper surface of the frame 41 and the upper surface of the weight main body 32. The top plate 47 closes an opening (not shown) between the weight main body 32 and the frame 41. Further, the battery pack 30 has a weight body 32, a bottom portion 33, a first column portion 43, and a first end opening 30 b surrounded by a top plate 47 on the longitudinal direction one end 33 c side of the bottom portion 33. Further, the battery pack 30 has a weight body 32, a bottom portion 33, a second column portion 44, and the other end side opening 30 c surrounded by the top plate 47 on the other end 33 d side of the bottom portion 33 in the longitudinal direction. . The one end side opening 30b and the other end side opening 30c are closed by a lid member 45.

  A plurality of battery modules 50 are provided on the surface 32 a of the weight body 32. Two battery modules 50 are mounted on each of the bottom 33, the first protrusion 34, and the second protrusion 35. That is, in the present embodiment, the bottom 33, the first projecting portion 34, and the second projecting portion 35 function as a mounting portion.

  On the third protrusion 36, a housing case 81 in which a control device (for example, an inverter) for controlling the battery module 50 is housed and a junction box 82 in which a relay, a wiring, and the like are housed are placed.

  As shown in FIGS. 4 and 5, the battery module 50 includes a square battery 51 as a battery cell (for example, a secondary battery such as a lithium ion secondary battery or a nickel hydride storage battery) held by a battery holder 60. The heat transfer plate 70 is interposed between the adjacent square batteries 51. In the battery module 50, end plates 52 are provided at both ends of the prismatic battery 51 in the parallel direction. A bolt B1 is inserted into one end plate 52, and the bolt B1 is screwed into a nut N on the other end plate 52 side with all the battery holders 60 inserted. Thereby, the square battery 51 and the battery holder 60 are clamped by the end plate 52.

  As shown in FIG. 6, a bracket 53 is fixed to the outer surface of each end plate 52 (the surface opposite to the surface facing the battery module 50). Then, the bolt B inserted through the bracket 53 passes through the plate members 38, 39, 40 and is screwed to the weight body 32, so that the battery module 50 is thermally coupled to the weight body 32. is set up.

  As shown in FIG. 5, the battery holder 60 includes a holder main body 61 having a bottomed rectangular tube shape and rectangular parallelepiped leg portions 62 protruding from the four corners of the outer surface of the holder main body 61. Specifically, the holder main body 61 extends in the thickness direction of the first covering portion 63 from the rectangular flat plate-like first covering portion 63 and the first end portion 63 a in the longitudinal direction of the first covering portion 63. And the rectangular flat plate-like second covering portion 64. In addition, a rectangular flat plate-like third covering portion 65 extending in the thickness direction of the first covering portion 63 is provided at the second end portion 63 b in the longitudinal direction of the first covering portion 63. A rectangular flat plate-like fourth covering portion 66 extending in the thickness direction of the first covering portion 63 is provided at the first end portion 63 c in the short direction of the first covering portion 63. A rectangular flat plate-like fifth covering portion 67 extending in the thickness direction of the first covering portion 63 is provided on the second end portion 63 d in the short side direction of the first covering portion 63. A region surrounded by the covering portions 63 to 67 is a housing portion S in which the square battery 51 is housed. The dimension in the short direction of the fifth covering portion 67 is slightly smaller than the dimension in the short direction of the fourth covering portion 66.

  The leg part 62 protrudes from the longitudinal direction both ends of the 2nd coating | coated part 64 and the 3rd coating | coated part 65 in the longitudinal direction of each coating | coated part 64,65. The leg portion 62 is provided with an insertion hole 62 a through which the bolt B <b> 1 is inserted, penetrating in the longitudinal direction of the leg portion 62.

  The heat transfer plate 70 includes a main body portion 71 having a rectangular flat plate shape, and a rectangular flat plate-like heat radiating portion 72 extending from the first longitudinal end portion 71 a of the main body portion 71 in the thickness direction of the main body portion 71. The heat radiating portion 72 of the heat transfer plate 70 covers the second covering portion 64 of the battery holder 60. Thereby, in the battery module 50, the heat radiating part 72 is exposed on the second covering part 64 side in the battery holder 60. The heat radiating portion 72 is in contact with the plate members 38, 39 and 40. Further, the heat transfer plate 70 has the main body portion 71 in contact with the surface of the rectangular battery 51 in the thickness direction. Therefore, each battery module 50 is in contact with the plate members 38, 39, and 40 (standing portions) via the heat radiating portion 72 of the heat transfer plate 70.

  The end plate 52 includes a plate main body 54 having a rectangular flat plate shape, and insertion portions 55 provided at four corners of the plate main body 54. The insertion portion 55 is provided with an insertion hole 55a through which the bolt B1 is inserted, penetrating in the thickness direction of the end plate 52. The end plate 52 and the battery holder 60 are provided so that the insertion hole 55a and the insertion hole 62a face (communicate) with each other.

Next, the operation of the battery pack 30 in this embodiment will be described.
In order to drive the traveling motor M1 and the cargo handling motor M2, when the square battery 51 of each battery module 50 discharges or charges each square battery 51, the square battery 51 generates heat. When the square battery 51 generates heat, this heat is conducted to the main body portion 71 of the heat transfer plate 70, and the heat conducted to the main body portion 71 is conducted from the heat radiating portion 72 to the weight main body 32. At this time, the heat radiating portion 72 of the heat transfer plate 70 is in contact with the plate members 38, 39, and 40 made of a material having better thermal conductivity than the weight main body 32 (the portion where the battery module 50 does not contact). As compared with the case where the heat radiating portion 72 of the heat transfer plate 70 is in direct contact with the weight main body 32, heat is easily diffused. Then, the heat diffused in the plate members 38, 39, 40 is diffused in the weight main body 32. In this way, the heat generated by the square battery 51 can be efficiently conducted to the counterweight 31 (installed body), and the heat dissipation of the battery module 50 can be enhanced.

  In this embodiment, the volume of each plate member 38,39,40 is so large that the plate member 38,39,40 located in the perpendicular direction upper direction. That is, the volume of the plate members 38, 39, and 40 that come into contact with the battery module 50 placed on the placement portion above in the vertical direction is larger. When each battery module 50 (square battery) generates heat and the heat medium around each battery module 50 is heated, the heat medium moves upward in the vertical direction. As a result, the ambient temperature around the battery module 50 positioned vertically above is higher than the ambient temperature around the battery module 50 positioned vertically below. And the temperature of the battery module 50 located in the upper part in the vertical direction is likely to increase. By increasing the volume of the plate members 38, 39, and 40 that are in contact with the battery module 50 that is positioned upward in the vertical direction, the heat capacity of the plate members 38, 39, and 40 is increased, and the battery module 50 that is positioned upward in the vertical direction. The plate members 38, 39, and 40 are likely to absorb heat. For this reason, it is suppressed that one of the battery modules 50 stacked in the vertical direction is excessively heated, and the temperature difference between the battery modules 50 can be reduced.

  By the way, a material having good thermal conductivity tends to increase in brittleness as the thermal conductivity increases. For example, aluminum, which is the material of the plate members 38, 39, 40, is more fragile than iron, which is the material of the weight body 32. When the bottom 33 and the protrusions 34 and 35 are not provided, the load of the battery module 50 is concentrated on the plate members 38, 39 and 40. At this time, if the plate members 38, 39, and 40 cannot support the load of the battery module 50, the plate members 38, 39, and 40 may collapse and the battery module 50 may fall off. In addition, it may be possible to limit the load of the battery module 50 in consideration of the durability of the plate members 38, 39, and 40. However, the number of the square batteries 51 included in the battery module 50 may have to be reduced. The output (power) required for the battery module 50 may not be ensured.

  As in the present embodiment, the bottom 33, the first protrusion 34, and the second protrusion 35 are protruded from the weight main body 32, and the battery module 50 is placed on the bottom 33, so that the battery module 50 has the bottom 33, It is supported by the first protrusion 34 and the second protrusion 35. Since the load of the battery module 50 is distributed not only to the plate members 38, 39, and 40 but also to these placement portions, the load applied to the plate members 38, 39, and 40 is reduced.

  For this reason, the lowering of the strength of the standing portion that occurs when the plate members 38, 39, 40 are provided in order to improve the heat dissipation of the battery module 50, the bottom 33, the first protrusion 34, and the second protrusion. It can be supplemented by part 35.

Therefore, according to the above embodiment, the following effects can be obtained.
(1) Plate members 38, 39, and 40 are provided on the surface 32a of the weight body 32 of the counterweight 31, and the battery module 50 is in contact with the plate members 38, 39, and 40. The plate members 38, 39, and 40 are manufactured from a material (aluminum) that has better thermal conductivity than the weight main body 32 and the bottom portion 33 (the portion where the battery module 50 is not in contact). For this reason, the heat generated by the battery module 50 is easily diffused to the plate members 38, 39, and 40, and the heat dissipation of the battery module 50 is improved. In addition, the erection part has plate members 38, 39, and 40 at least a part of the part that comes into contact with the battery module 50, so that the fragility of the erection part is increased, but the erection part protrudes from the weight body 32. The load is distributed by providing a portion and placing the battery module 50 on the placement portion. For this reason, it is possible to prevent the battery module 50 from dropping from the standing portion while improving the heat dissipation of the battery module 50.

  (2) By providing the bottom 33 and the protrusions 34 and 35, the contact area between the counterweight 31 and the battery module 50 is increased, and the heat dissipation performance for the battery module 50 is improved. Further, since the heat capacity of the counterweight 31 is increased by the amount of the bottom 33 and the protrusions 34 and 35, the heat dissipation of the battery module 50 is further improved.

  (3) The counterweight 31 has an iron bottom 33. When a part of the standing part is a good heat conducting part, the weight of the standing part is lighter than when the good heat conducting part is made of iron. By manufacturing the bottom 33 with iron, the weight of the counterweight 31 can be increased and the center of gravity can be lowered.

  (4) The plate members 38, 39, and 40 have a larger volume as the plate members 38, 39, and 40 located in the upper vertical direction. For this reason, the battery module 50 located in the upper part in the vertical direction is more easily absorbed by the plate members 38, 39, and 40, and the temperature difference between the battery modules 50 can be reduced. If the temperature difference between the battery modules 50 is large, the life of the battery pack 30 may be shortened. Therefore, shortening the lifetime of the battery pack 30 by suppressing the temperature difference between the battery modules 50 is suppressed.

  (5) The counterweight 31 is used as an installation object. The counterweight 31 is a member that is originally provided in the forklift 10, and by using this member as an installation object, it is not necessary to prepare an installation object separately. For this reason, it is suppressed that the number of parts increases.

In addition, you may change the said embodiment as follows.
In the embodiment, the plate members 38, 39, and 40 (good heat conducting portions) may be provided in a part of the portion of the counterweight 31 with which the battery module 50 abuts.

  In the embodiment, the entire weight body 32 may be manufactured from aluminum, copper, or the like, and the entire weight body 32 may be used as a good heat conducting portion. In this case, it is not necessary to provide the plate members 38, 39, and 40. Moreover, you may manufacture a mounting part from aluminum, copper, etc.

  In the embodiment, plate members 38, 39, and 40 made of a material having good thermal conductivity may be provided on the bottom 33 and the protrusions 34 and 35, respectively. When the heat generated from the battery module 50 diffuses to the bottom 33 and the protrusions 34 and 35, the heat is easily diffused through the plate members 38, 39, and 40, and the heat dissipation of the battery module 50 is further improved. .

  In the embodiment, the plate members 38, 39, and 40 may be made of copper. Moreover, you may manufacture from materials other than aluminum and copper, for example, you may use silver, gold | metal | money, etc. whose heat conductivity is better than iron.

  In embodiment, you may use other than the counterweight 31 as a to-be-installed body. For example, in the case where the battery pack 50 is configured by fixing the battery module 50 to the housing, the housing may be an object to be installed, and the mounting portion may be formed on the side wall of the housing extending in the vertical direction.

  In the embodiment, the bottom 33 and the protrusions 34, 35, and 36 may have any shape. Similarly, the shape of the weight main body 32 may be any shape. For example, it may be a circular shape in plan view or a polygonal shape such as a triangular shape or a quadrangular shape.

  In the embodiment, each protrusion 34, 35, 36 may be provided separately from the weight main body 32. In this case, each protrusion 34, 35, 36 is fixed to the weight main body 32 by, for example, bolt fastening or an adhesive.

In the embodiment, a cylindrical battery other than the square battery 51 or a laminated battery may be used as the battery cell.
In the embodiment, the square battery 51 may not be held by the battery holder 60. That is, the battery module 50 may not include the battery holder 60. Further, the battery module 50 may not include the heat transfer plate 70. In this case, the square battery 51 may be in contact with the plate members 38, 39 and 40.

  In the embodiment, each protrusion 34, 35, 36 only has to protrude from the weight body 32 in a direction intersecting the vertical direction, and within the range in which the battery module 50 can be placed, above and below the vertical direction. It may be slightly inclined.

  (Circle) in embodiment, the battery module 50 may be one. In this case, the number of placement units is also one. Further, the number of battery modules 50 may be increased. In this case, the number of placement units is also changed according to the number of battery modules 50.

  In the embodiment, the weight main body 32 erected in the vertical direction may be erected with a slight inclination with respect to the vertical direction. Further, the bottom 33 extending in the horizontal direction may be extended slightly inclined with respect to the horizontal direction.

A counterweight provided on a power shovel (industrial vehicle) may be used as a wall member.
Next, the technical idea that can be grasped from the above embodiment and other examples will be described below.

  (A) An industrial vehicle equipped with the battery pack according to any one of claims 1 to 4.

  DESCRIPTION OF SYMBOLS 10 ... Forklift, 30 ... Battery pack, 31 ... Counter weight, 32 ... Weight main body, 33 ... Bottom part, 34 ... 1st protrusion part, 35 ... 2nd protrusion part, 38 ... 1st board member, 39 ... 1st 2 plate members, 40... Third plate member, 50... Battery module, 51.

Claims (4)

A body to be installed having a standing portion that is erected in the vertical direction, and a mounting portion that projects from the erected portion in a direction that intersects the vertical direction;
A battery module having a plurality of battery cells,
The battery module abuts on the standing portion and is placed on the placement portion,
The standing portion has a good heat conducting portion made of a material having better thermal conductivity than at least a portion of the portion that comes into contact with the battery module as compared with a portion that does not come into contact with the battery module in the mounted body. A battery pack comprising:   The battery pack according to claim 1, wherein the good heat conducting portion is made of aluminum or copper. The mounted object includes a counterweight mounted on an industrial vehicle,
The battery pack according to claim 1, wherein the standing portion is erected from an iron bottom portion extending in a horizontal direction. The object to be installed has a plurality of the placement units described above,
The battery module is placed on each of the placement units,
The battery pack according to any one of claims 1 to 3, wherein a volume of the good heat conducting portion located in a vertically upward direction is larger.