JP2019046750A - Battery pack - Google Patents

Abstract

To provide a battery pack in which generation of variations in lives of a plurality of battery cells is suppressed.SOLUTION: A battery pack has a plurality of battery cells and a battery case 40 for storing a battery stack in which the plurality of battery cells are vertically aligned. In the battery case, first to sixth opening windows 61 to 66 corresponding to the plurality of battery cells are formed. The opening areas of the plurality of opening windows corresponding to the plurality of battery cells increase from the battery cells located on the lower side in the vertical direction toward the battery cells located on the upper side in the vertical direction.SELECTED DRAWING: Figure 4

Description

  The disclosure described herein relates to a battery pack having a plurality of battery cells.

  As shown in Patent Document 1, a battery unit provided with a battery module is known. The assembled battery module includes a plurality of single cells and a battery case for accommodating the plurality of single cells.

Patent No. 5942645

  In the battery pack shown in Patent Document 1, a plurality of single cells are vertically stacked in the battery case. The temperature distribution in the battery case becomes higher as it goes from the lower side to the upper side in the vertical direction. Therefore, there is a possibility that the temperature of the unit cell positioned on the upper side in the vertical direction may be higher than that of the unit cell positioned on the lower side in the vertical direction. Temperature variations occur in the plurality of unit cells (battery cells), which may cause variations in the life of the plurality of battery cells.

  Therefore, the disclosure of the present specification aims to provide a battery pack in which variations in the life of a plurality of battery cells are suppressed.

One of the disclosures includes a plurality of battery cells (31 to 36),
A battery case (40) for storing a battery stack (30i, 30j) in which a plurality of battery cells are vertically aligned;
The battery case is formed with a plurality of opening windows (55, 61 to 66, 63a to 63c, 64a, 64b) corresponding to a plurality of battery cells,
The opening areas of the plurality of opening windows corresponding to the plurality of battery cells increase as going from the battery cell located on the lower side in the vertical direction to the battery cell located on the upper side.

  According to this, the heat dissipation of each battery cell (31 to 36) can be enhanced as it goes from the lower side to the upper side in the vertical direction. Thereby, it is suppressed that a temperature variation arises in each battery cell (31-36) arranged in a perpendicular direction. As a result, the occurrence of variations in the life of the plurality of battery cells (31 to 36) is suppressed.

One of the other disclosures includes a plurality of battery cells (31 to 36);
A battery case (40) for storing a battery stack (30i, 30j) in which a plurality of battery cells are arranged horizontally in the horizontal direction;
In the battery case, opening windows (55, 61 to 66, 63a to 63c, 64a, 64b) corresponding to the battery stack are formed,
The opening area of the opening window is larger above the geometric center of the battery stack vertically than below the vertical direction orthogonal to the horizontal direction from the geometric center (GC2) of the battery stack.

  Thus, the plurality of battery cells (31 to 36) are arranged in the horizontal direction, and the opening windows (55, 61 to 66, 63a to 63c, 64a, 64b) corresponding to the plurality of battery cells (31 to 36) are batteries. It is formed in the case (40). Therefore, the heat dissipation of the plurality of battery cells (31 to 36) with respect to the temperature distribution in the vertical direction is equalized.

  Further, the opening area of the opening windows (55, 61 to 66, 63a to 63c, 64a, 64b) is larger in the upper side in the vertical direction than in the lower side in the vertical direction. Thereby, the heat dissipation in the upper side in the vertical direction in the battery stack (30i, 30j) can be improved more than the heat dissipation in the lower side in the vertical direction. As a result, the temperature distribution in the battery stack (30i, 30j) is equalized. The temperature distribution in the battery cells (31 to 36) is equalized. By the above, it is suppressed that a variation arises in the lifetime of a plurality of battery cells (31 to 36).

  The elements described in the claims and in the means for solving the problems are indicated by parentheses. The parenthesized reference numerals are provided to simply show the correspondence with the components described in the embodiment, and do not necessarily indicate the elements described in the embodiment. The description of the parenthesized reference does not narrow the scope of the claims.

It is an exploded perspective view of a battery pack. It is a disassembled perspective view of the battery module of 1st Embodiment. It is a chart showing a battery case. It is a chart for explaining the opening window of a battery case. It is a chart for explaining temperature distribution in a battery case without an opening window. It is a chart for explaining a modification. It is a chart for explaining a modification. It is a chart for explaining a modification. It is a chart for explaining a modification. It is a chart for explaining a modification. It is a chart for explaining a modification. It is a chart for explaining a modification. It is a chart for explaining a modification. It is a chart showing a battery module of a 2nd embodiment. It is a chart for explaining a modification. It is a chart for explaining a modification. It is a chart for explaining a modification. It is a sectional view for explaining a modification.

  Hereinafter, embodiments will be described based on the drawings.

First Embodiment
The battery pack 100 according to the present embodiment will be described based on FIGS. 1 to 5.

<Summary of power supply system>
The battery pack 100 is mounted on a vehicle and constitutes a power supply system together with other in-vehicle devices. Lead-acid battery is one of the in-vehicle devices. The battery pack 100 has a battery pack 30. The power supply system constructs a two power supply system by the lead storage battery and the battery assembly 30.

  There is an engine as another in-vehicle device. A vehicle equipped with a power supply system has an idle stop function of stopping the engine when a predetermined stop condition is satisfied, and restarting the engine when the predetermined start condition is satisfied.

  The power supply system further includes a starter motor, a rotating electric machine, an electric load, a host ECU, and an MGECU, in addition to the above-described lead storage battery and engine. The lead storage battery, the starter motor, the rotating electric machine, and the electrical load are each electrically connected to the battery pack 100 via a wire harness. Further, the host ECU and the MGECU are electrically connected to the lead storage battery and the battery pack 100 through the wiring.

  The starter motor starts the engine. The rotating electrical machine performs power running and power generation. An inverter is connected to the rotating electrical machine. The inverter converts a DC voltage supplied from at least one of the lead storage battery and the battery assembly 30 into an AC voltage. This alternating voltage is supplied to the rotating electrical machine. The electric rotating machine is thus powered.

  The rotating electrical machine is connected to the engine. The rotational energy generated by the power running of the rotating electrical machine is transmitted to the engine. This promotes engine rotation. As a result, vehicle travel is assisted. The rotating electrical machine also performs the function of rotating the crankshaft when the engine is restarted.

  The rotating electrical machine also has a function of generating power by at least one of rotational energy of the engine and rotational energy of the wheels of the vehicle. The AC voltage generated by the power generation of the rotary electric machine is converted to a DC voltage by the inverter. This DC voltage is supplied to each of the battery pack, the lead storage battery, and the electrical load.

  The engine burns fuel to generate propulsion of the vehicle. At the start of the engine, the crankshaft is rotated by the starter motor. However, when the engine is stopped once due to idle stop and then started again, the crankshaft is rotated by the rotating electrical machine if the above-mentioned predetermined start condition is satisfied.

  The electrical load has a general load and a protective load. Protective loads include in-vehicle devices that are more relevant to vehicle travel than general loads.

  The host ECU and the MGECU are one of various ECUs mounted on the vehicle. These various ECUs are electrically connected to one another via bus wiring to construct an in-vehicle network. The cooperative control of the various ECUs controls the combustion of the engine and the power generation and power running of the rotating electrical machine. The host ECU controls the battery pack. The MGECU controls the rotating electrical machine.

<Overview of Battery Pack>
Next, the battery pack 100 will be described. In the following, three directions orthogonal to each other will be referred to as a lateral direction, a longitudinal direction, and a height direction. In the present embodiment, the longitudinal direction is along the advancing and retracting direction of the vehicle. The lateral direction is along the lateral direction of the vehicle. The height direction is along the vertical direction of the vehicle. When the vehicle is at rest in a horizontal plane, the advancing and retracting direction and the left and right direction are in the horizontal direction, and the vertical direction is in the vertical direction.

  As shown in FIG. 1, the battery pack 100 has a case 10 and a battery module 20. Battery pack 100 also includes a wiring board 70, a switch 80, and a connection portion 90. The case 10 has a housing 11 and a cover 12. The battery module 20, the wiring board 70, the switch 80, and the connection portion 90 are housed in a housing space formed by the housing 11 and the cover 12.

  The housing 11 is produced by aluminum die casting. The housing 11 has a bottom wall 13 and an annular side wall 14 extending from the bottom wall 13. The housing 11 is formed with a flange 11 a for connecting to the body of the vehicle. The flange 11a and the body of the vehicle are mechanically and thermally connected via bolts. Thereby, battery pack 100 is fixed to the vehicle. The housing 11 may be manufactured by pressing iron or stainless steel. The bottom wall 13 corresponds to the bottom. The flange 11a corresponds to the connection portion.

  An opening is formed by the side wall 14 of the housing 11. When the vehicle is at rest in a horizontal plane, the opening of the housing 11 is open in the vertical direction. This opening is covered by the cover 12. This constitutes a storage space. The cover 12 is made of resin or metal. In the following, the bottom wall 13 side of the housing 11 in the height direction is referred to as the lower side, and the cover 12 side covering the opening of the housing 11 is referred to as the upper side.

  The case 10 (battery pack 100) of the present embodiment is provided below the seat of the vehicle. However, the arrangement of the battery pack 100 is not limited to this. Battery pack 100 can also be arranged, for example, in the space between the rear seat and the trunk room, and in the space between the driver's seat and the front passenger seat.

  The battery module 20 has an assembled battery 30 and a battery case 40 as shown in FIG. The battery assembly 30 has a plurality of battery cells, and the plurality of battery cells are housed in a battery case 40. The battery case 40 has a hole for passing a bolt. The housing 11 is formed with a bolt hole for fastening the bolt. The battery case 40 is fixed to the housing 11 by passing a bolt through these holes. The battery module 20 will be described in detail later.

  The wiring board 70 is a printed board on which a wiring pattern made of a conductive material is formed on at least one of the surface and the inside of the insulating substrate. A part of the switch 80 and a BMU (not shown) are mounted on the wiring board 70. The remaining switches 80 are mounted on the housing 11 via an insulating film 81. The control electrode of the switch 80 mounted on the housing 11 is electrically connected to the wiring substrate 70. An electric circuit is thus configured. The electric circuit is electrically connected to sensor elements for detecting states such as current, voltage, and temperature of the battery pack 30 and the switch 80 respectively. A submersion sensor for detecting submersion of the battery pack 100 is also connected to the electric circuit.

  The BMU mounted on the wiring board 70 controls the switch 80 based on at least one of the sensor element signal and the command signal from the host ECU. BMU is an abbreviation for battery management unit. The BMU determines the state of charge (SOC) of the battery pack 30 and the abnormality of the switch 80 based on the signal of the sensor element. SOC is an abbreviation of state of charge. The BMU outputs a signal (determination information) that has determined these SOCs and abnormalities to the host ECU.

  The host ECU determines the control of the switch 80 based on the determination information input from the BMU and the vehicle information input from other various ECUs. Then, the host ECU outputs a command signal including control of the determined switch 80 to the BMU.

  The BMU controls the switch 80 based on the command signal from the host ECU. When the BMU determines that the battery pack 100 is submerged from the signal of the submergence sensor, the BMU independently stops the output of the control signal to the switch 80. Thereby, the electrical connection of the battery assembly 30 is cut off.

  The connection portion 90 has an internal connection portion 91, an external connection terminal 92, and a restraint plate 93. The internal connection portion 91 functions to electrically connect the electric circuit and the external connection terminal 92 described above. The internal connection portion 91 has a conductive bus bar and a resin mounting portion for mounting the bus bar. One end of one of the plurality of bus bars is electrically connected to the output terminal of the battery module 20. The other end of the bus bar is connected to one of the plurality of external connection terminals 92. The electrical connection between the battery module 20 and the external connection terminal 92 via the bus bar is controlled by the switch 80 mounted on the housing 11 described above. The other bus bars function to connect the above electric circuit and the other external connection terminal 92.

  The external connection terminal 92 is connected to an end of a wire harness connected to the above-described in-vehicle device in addition to the other end of the bus bar. The external connection terminal 92 has a bolt and a nut. The other end of the bus bar and the end of the wire harness are passed through the bolt. A nut is fastened to the bolt in this inserted state. Thereby, the external connection terminal 92 and the wire harness are mechanically and electrically connected.

  The restraint plate 93 functions to fix the battery module 20 to the housing 11. The restraint plate 93 is disposed to face the bottom wall 13 of the housing 11 with the battery module 20 in the height direction. The restraint plate 93 has a hole for passing a bolt. The housing 11 is formed with a bolt hole for fastening the bolt. The restraint plate 93 is fixed to the housing 11 by passing a bolt through these holes.

  The restraint plate 93 and the battery module 20 may be designed to be in contact with each other when the restraint plate 93 and the battery module 20 are mounted on the housing 11 respectively, or may be designed not to be in contact with each other. Good. As described later, the battery module 20 has battery cells. The battery cell expands due to the generation of gas. Along with this, the battery case 40 accommodating the battery cells also expands.

  Due to this expansion, even if the restraint plate 93 and the battery module 20 (battery case 40) are initially designed not to contact with each other, both come into contact with each other. The restraint plate 93 functions to suppress the expansion of the battery module 20. Thereby, the displacement due to the thermal expansion of the battery module 20 is suppressed. As a result, the occurrence of an electrical connection failure at the connection portion between the battery module 20 and the bus bar is suppressed.

<Battery module>
Next, the battery module 20 will be described in detail. As described above, the battery module 20 has the battery assembly 30 and the battery case 40. The assembled battery 30 is smaller in size and lighter in weight than the lead storage battery. The battery assembly 30 has a higher energy density than the lead storage battery.

  The battery assembly 30 has a plurality of battery cells connected in series. The battery cell is specifically a lithium ion battery. Lithium ion batteries generate an electromotive force by a chemical reaction. A current flows in the battery cell due to the generation of the electromotive voltage. The battery cell generates heat and generates gas inside. Thereby, the battery cell expands. The specific example of the battery cell is not limited to the above example. For example, as the battery cell, a secondary battery such as a nickel hydrogen secondary battery or an organic radical battery can be adopted.

  The battery cell has a square pole shape. Therefore, the battery cell has six sides. The battery cell has a first main surface 30a and a second main surface 30b facing in the height direction. The battery cell has a laterally facing first side 30c and a second side 30d. The battery cell has an upper end face 30e and a lower end face 30f facing in the longitudinal direction. Among the six surfaces, the first main surface 30a and the second main surface 30b are larger in area than the other surfaces. The battery cell has a thin flat shape having a length (thickness) between the first main surface 30a and the second main surface 30b.

  A positive electrode terminal 30g and a negative electrode terminal 30h are formed on the upper end surface 30e of the battery cell. The positive electrode terminal 30g and the negative electrode terminal 30h are spaced apart and aligned in the lateral direction. The positive electrode terminal 30g is located on the first side 30c side. The negative electrode terminal 30 h is located on the second side surface 30 d side.

  The battery assembly 30 includes first to fifth battery cells 31 to 35 as battery cells. As shown in FIG. 2, the first battery cell 31, the fourth battery cell 34, and the fifth battery cell 35 are sequentially arranged in order from the lower side to the upper side in the height direction, and the first battery stack 30i is It is configured. The second main surfaces 30b of the first battery cell 31 and the fourth battery cell 34 face each other in the height direction. The first main surfaces 30a of the fourth battery cell 34 and the fifth battery cell 35 face each other in the height direction. Thus, the positive electrode terminals 30g and the negative electrode terminals 30h are alternately arranged in the height direction.

  Similarly, the second battery cell 32 and the third battery cell 33 are arranged side by side sequentially from the lower side to the upper side in the height direction, and the second battery stack 30 j is configured. The second main surfaces 30 b of the second battery cell 32 and the third battery cell 33 face each other in the height direction. Thus, the positive electrode terminals 30g and the negative electrode terminals 30h are alternately arranged in the height direction.

  The first battery stack 30i and the second battery stack 30j are arranged in the lateral direction. The positive electrode terminal 30g of the first battery cell 31 and the negative electrode terminal 30h of the second battery cell 32 are arranged in the lateral direction. The negative electrode terminal 30 h of the fourth battery cell 34 and the positive electrode terminal 30 g of the third battery cell 33 are aligned in the lateral direction. The five battery cells are accommodated in the battery case 40 in the arrangement described above.

  The battery case 40 has a housing portion 41 for housing the battery assembly 30, and a lid portion 42 for closing the opening 40a of the housing portion 41. The housing portion 41 and the lid portion 42 are each formed of a resin material. In the main body portion made of resin material of the housing portion 41 and the lid portion 42, a conductive material for performing a function as a mechanical connection or an electrical connection is insert-molded.

  As described above, the storage section 41 is configured with the opening 40a. The assembled battery 30 is inserted into the inside of the storage portion 41 in such a manner that the electrode terminal of the battery cell protrudes out of the opening 40 a. The lid portion 42 is mechanically connected to the storage portion 41 by a bolt or the like so as to cover a part of the battery cell that protrudes out from the storage portion 41. As a result, the opening 40 a of the storage unit 41 is closed by the lid 42, and the battery assembly 30 is stored in the battery case 40.

  The lid portion 42 includes a series terminal for electrically connecting a plurality of battery cells. A part of the series terminal is exposed to the outside from the lid portion 42. In a state in which the battery pack 30 is housed in the battery case 40, series terminals respectively corresponding to one positive electrode terminal 30g and the other negative electrode terminal 30h of two battery cells connected in series are in contact with each other. In this contact state, the positive electrode terminal 30g and the negative electrode terminal 30h are welded and connected to corresponding series terminals by a laser or the like. Thus, five battery cells are connected in series.

  Specifically, the positive electrode terminal 30g of the first battery cell 31 and the negative electrode terminal 30h of the second battery cell 32 are electrically connected via corresponding series terminals. The positive electrode terminal 30 g of the second battery cell 32 and the negative electrode terminal 30 h of the third battery cell 33 are electrically connected via corresponding series terminals. The positive electrode terminal 30g of the third battery cell 33 and the negative electrode terminal 30h of the fourth battery cell 34 are electrically connected via corresponding series terminals. The positive electrode terminal 30g of the fourth battery cell 34 and the negative electrode terminal 30h of the fifth battery cell 35 are electrically connected via corresponding series terminals.

  Further, the lid portion 42 includes an output terminal 43 connected to the positive electrode terminal 30g of the fifth battery cell 35 positioned at the highest potential among the five battery cells connected in series. Further, the cover 42 includes a ground terminal 44 connected to the negative electrode terminal 30 h of the first battery cell 31 located at the lowest potential. Each of the output terminal 43 and the ground terminal 44 is exposed to the outside from the main body of the lid 42.

  With the assembled battery 30 housed in the battery case 40, the positive electrode terminal 30g of the fifth battery cell 35 and the output terminal 43 are in contact with each other. The negative electrode terminal 30 h of the first battery cell 31 contacts the ground terminal 44. In this contact state, the positive electrode terminal 30g of the fifth battery cell 35 and the output terminal 43 are welded and joined by a laser or the like. The negative electrode terminal 30 h of the first battery cell 31 and the ground terminal 44 are welded and joined by a laser or the like.

  The series terminal, the output terminal 43, and the ground terminal 44 described above may not be insert-molded and fixed to the main body of the lid 42, but may be fixed to the main body by, for example, screws. In this case, a mounting hole penetrating in the vertical direction is formed in the main body of the lid 42 in accordance with the series terminal, the output terminal 43 and the ground terminal 44. The electrode terminal of the battery cell is brought into contact with the corresponding series terminal, the output terminal 43 and the ground terminal 44 through the mounting hole, and welding is performed in the contact state.

<Structure of Storage Unit>
Hereinafter, the detailed configuration of the storage portion 41 of the battery case 40 will be described. The storage portion 41 has an upper wall 45 and a lower wall 46 aligned in the vertical direction. The storage portion 41 also has a first side wall portion 47 and a second side wall portion 48 that connect the upper wall portion 45 and the lower wall portion 46 side by side in the lateral direction. Furthermore, the storage portion 41 closes one of two openings formed by connecting the upper wall 45, the lower wall 46, the first side wall 47, and the second side wall 48 to each other. In aspect, it has a bottom wall 49 connecting these four walls to one another. According to the above configuration, the storage portion 41 is configured with one opening 40 a which is opened in the vertical direction and aligned with the bottom wall 49 in the vertical direction.

  The first battery stack 30i and the second battery stack 30j are inserted into the housing portion 41 through the opening 40a. The length in the height direction of these battery stacks is different. Therefore, the lengths in the height direction of the first side wall 47 and the second side wall 48 are different. The central portion of the upper wall portion 45 is bent (curved) in the height direction, and the position of the portion of the upper wall portion 45 corresponding to the first battery stack 30i and the position in the height direction of the portion corresponding to the second battery stack 30j are It is different.

  The storage portion 41 has a dividing wall portion 50 that divides the internal space constituted by the five wall portions into the first stack storage space 41a and the second stack storage space 41b. The partition wall 50 extends in the longitudinal direction and connects the upper wall 45 and the lower wall 46. The dividing wall 50 is located between the first side wall 47 and the second side wall 48 in the lateral direction.

  The storage portion 41 has a partition wall portion 51 for dividing the first stack storage space 41a and the second stack storage space 41b into storage spaces corresponding to one battery cell. The partition wall 51 faces in the height direction.

  Two partition walls 51 are provided in the first stack storage space 41a. The two partition walls 51 connect the first side wall 47 and the partition wall 50, and partition the first stack storage space 41a into three storage spaces. These three storage spaces are arranged in the height direction.

  Hereinafter, the storage spaces arranged in order from the lower side to the upper side in the height direction will be referred to as a first storage space 41c, a fourth storage space 41f, and a fifth storage space 41g. The first battery cell 31 is accommodated in the first accommodation space 41c. The fourth battery cell 34 is accommodated in the fourth accommodation space 41f. The fifth battery cell 35 is accommodated in the fifth accommodation space 41g.

  One partition wall 51 is provided in the second stack storage space 41 b. The one partition wall portion 51 connects the second side wall portion 48 and the partition wall portion 50, and partitions the second stack storage space 41b into two storage spaces. These two storage spaces are aligned in the height direction.

  Hereinafter, the storage spaces arranged in order from the lower side to the upper side in the height direction will be referred to as a second storage space 41 d and a third storage space 41 e. The second battery cell 32 is accommodated in the second accommodation space 41 d. The third battery cell 33 is accommodated in the third accommodation space 41e.

  As shown in FIG. 2, the first storage space 41 c and the second storage space 41 d are arranged in the lateral direction. The third storage space 41e and the fourth storage space 41f are arranged in the lateral direction. With the above arrangement of the storage space, a vacant space for one storage space is formed on the upper side of the fourth storage space 41f, which is aligned with the fifth storage space 41g in the lateral direction. At least a part of the wiring board 70 is provided in the empty space.

  As shown in FIG. 3 and FIG. 4, an opening window corresponding to the above-mentioned five storage spaces is formed in the storage part 41. In other words, the storage window 41 is formed with opening windows corresponding to the five battery cells. An opening window is formed in the storage portion 41 at a portion facing the battery cell. In FIG. 4, the opening windows are hatched to clarify the opening windows.

  As shown in column (a) of FIG. 4, the lower wall portion 46 is formed with two opening windows. One of the two opening windows, the first opening window 61, is formed at a portion of the lower wall portion 46 that constitutes the first storage space 41c. The other second opening window 62 is formed in a portion of the lower wall portion 46 that constitutes the second storage space 41 d. In the present embodiment, the opening areas of the first opening window 61 and the second opening window 62 are equal.

  As shown in column (b) of FIG. 4, the bottom wall 49 is formed with two opening windows. One third opening window 63 of the two opening windows is formed in a portion of the bottom wall 49 that constitutes each of the first storage space 41 c, the fourth storage space 41 f, and the fifth storage space 41 g. There is. The other fourth opening window 64 is formed in a portion of the bottom wall 49 that constitutes the second storage space 41 d and the third storage space 41 e. The third opening window 63 has an opening area larger than that of the fourth opening window 64. As described above, one opening window is formed in a plurality of storage spaces corresponding to a plurality of battery cells, whereby a plurality of opening windows corresponding to a plurality of battery cells are configured.

  In the (b) column of FIG. 4, portions corresponding to the first storage space 41 c, the fourth storage space 41 f, and the fifth storage space 41 g in the third opening window 63 are clearly indicated by different hatchings. Similarly, portions corresponding to the second storage space 41 d and the third storage space 41 e in the fourth opening window 64 are clearly indicated by different hatchings. In order to clearly indicate that both the hatching applied to the portion of the third opening window 63 corresponding to the first storage space 41 c and the hatching applied to the first opening window 61 correspond to the first storage space 41 c I have to. Similarly, the hatching applied to the portion corresponding to the second storage space 41d in the fourth opening window 64 and the hatching applied to the second opening window 62 are the same in order to clearly indicate that both correspond to the second storage space 41d. The hatching of.

  As shown in column (c) of FIG. 4, the upper wall 45 is formed with two opening windows. The fifth opening window 65 of one of the two opening windows is formed in a portion of the upper wall 45 that constitutes the fifth storage space 41 g. The other sixth opening window 66 is formed in a portion of the upper wall 45 that constitutes the third storage space 41 e. Each of the fifth opening window 65 and the sixth opening window 66 is located closer to the bottom wall 49 than the opening 40 a of the storage unit 41 in the longitudinal direction. Specifically, all of the fifth opening window 65 and the sixth opening window 66 pass through the center point in the longitudinal direction of the storage portion 41 shown by the broken line in (c) of FIG. Is also located on the bottom wall 49 side in the longitudinal direction. In the present embodiment, the opening areas of the fifth opening window 65 and the sixth opening window 66 are equal.

  The same hatching to clearly indicate that both the hatching applied to the fifth opening window 65 and the hatching applied to the portion of the third opening window 63 corresponding to the fifth storage space 41g correspond to the fifth storage space 41g. I have to. Similarly, the same hatching to clearly indicate that both the hatching applied to the sixth opening window 66 and the hatching applied to the portion of the fourth opening window 64 corresponding to the third storage space 41e correspond to the third storage space 41e. I have to.

  As described above, in the storage unit 41, the windows corresponding to the battery cells of the first stack storage space 41a (the first battery stack 30i) and the second stack storage space 41b (the second battery stack 30j) are provided. It is formed.

  The opening windows corresponding to the first battery cells 31 of the first battery stack 30i are portions corresponding to the first storage space 41c in the first opening window 61 and the third opening window 63. The opening windows face the first battery cell 31. The total value of the open areas of these open windows is hereinafter referred to as a first area.

  The opening window corresponding to the fourth battery cell 34 is a portion corresponding to the fourth storage space 41 f in the third opening window 63. The third opening window 63 faces the fourth battery cell 34. Hereinafter, the opening area of the opening window is referred to as a fourth area.

  The opening window corresponding to the fifth battery cell 35 is a portion corresponding to the fifth opening window 65 and the fifth storage space 41 g of the third opening window 63. These opening windows face the fifth battery cell 35. The total value of the opening areas of these opening windows is hereinafter referred to as a fifth area.

  These three areas have the following magnitude relationship. That is, the fourth area is larger than the first area. The fifth area is larger than the fourth area. Thus, the opening area of the opening window corresponding to the fourth battery cell 34 positioned on the upper side in the height direction than the first battery cell 31 is larger than the opening area of the opening window corresponding to the first battery cell 31 It has become. The opening area of the opening window corresponding to the fifth battery cell 35 positioned above the fourth battery cell 34 in the height direction is larger than the opening area of the opening window corresponding to the fourth battery cell 34 .

  On the other hand, the opening window corresponding to the second battery cell 32 of the second battery stack 30 j is a portion corresponding to the second opening space 62 d and the second storage space 41 d in the fourth opening window 64. The opening windows face the second battery cell 32. The total value of the open areas of these open windows is hereinafter referred to as a second area.

  The opening windows corresponding to the third battery cells 33 are portions corresponding to the sixth opening window 66 and the third storage space 41 e in the fourth opening window 64. The opening windows face the third battery cell 33. The total value of the open areas of these open windows is hereinafter referred to as a third area.

  These two areas have the following magnitude relationship. That is, the third area is larger than the second area. Thus, the opening area of the opening window corresponding to the third battery cell 33 positioned above the second battery cell 32 in the height direction is larger than the opening area of the opening window corresponding to the second battery cell 32. It has become.

  As described above, in each of the first battery stack 30i and the second battery stack 30j, the battery cells located on the lower side in the height direction move from the battery cells located on the upper side to the battery cells located on the upper side. The opening area of the opening window is increased.

  In addition, several% to about 25% of the surface area of the battery cell can be adopted as each of the first to fifth areas described above. The total area of the first to fifth areas can be about several% to 50% of the surface area of the battery case. Each of the first to fifth areas is determined by the temperature distribution in the battery pack 100 and the required heat dissipation characteristics. The total area of the first to fifth areas is determined according to the strength of the battery case 40.

<Function effect>
Next, the function and effect of the battery pack 100 will be described. FIG. 5 shows a configuration in which the opening window is not formed in the battery case 40, and the temperature in the battery pack 100 in that case. This shows that the vehicle is stopped in the horizontal plane, and the vertical direction of the vehicle, that is, the height direction is along the vertical direction.

  In this case, as shown in the (b) column of FIG. 5, the temperature distribution in the battery case 40 becomes higher as it goes from the lower side to the upper side in the vertical direction. Therefore, the temperature of the battery cell positioned on the upper side in the vertical direction may be higher than that of the battery cell positioned on the lower side in the vertical direction. As a result, temperature variations occur in the plurality of battery cells, which may cause variations in the life of the plurality of battery cells.

  On the other hand, as described above, the battery case 40 of the battery pack 100 is formed with an opening window corresponding to each battery cell. And the opening area of the opening window corresponding to each battery cell becomes large as it goes to the battery cell located above from the battery cell located below the height direction. That is, the opening area of the opening window corresponding to each battery cell increases as going from the battery cell located on the lower side in the vertical direction to the battery cell located on the upper side in the vertical direction.

  According to this, the heat dissipation of each battery cell is enhanced as it goes from the lower side to the upper side in the vertical direction. This suppresses the occurrence of temperature variations in the respective battery cells arranged in the vertical direction. As a result, the occurrence of variations in the life of the plurality of battery cells is suppressed.

  Furthermore, for example, in order to improve the heat dissipation of each of the plurality of battery cells, the opening area of the opening window becomes smaller compared to the configuration in which large opening windows are formed in the battery case corresponding to each of the plurality of battery cells. Thereby, the reduction in strength of the battery case 40 is suppressed. As a result, the function of suppressing the expansion of the battery cell by the battery case 40 is suppressed from being impaired.

  Further, in the present embodiment, a total area of the first area to the fifth area is a few% to 50% of the surface area of the battery case 40. As a result, the strength of the battery case 40 is suppressed to be extremely low. It is suppressed that the function which suppresses expansion of the battery cell by battery case 40 becomes extremely low.

  As shown in the column (b) of FIG. 5, the temperature inside the battery pack 100 gradually decreases in temperature as it approaches the cover 12 side. This is because heat is dissipated through the cover 12 because the cover 12 is in contact with the external atmosphere.

  A fifth opening window 65 corresponding to the fifth battery cell 35 and a sixth opening window 66 corresponding to the third battery cell 33 are formed in the upper wall 45 located on the upper side in the height direction of the storage unit 41. There is. Thereby, the heat dissipation of each of the fifth battery cell 35 and the third battery cell 33, in which the temperature tends to be high due to the temperature distribution in the battery case 40, is enhanced.

  Each of the fifth opening window 65 and the sixth opening window 66 formed in the upper wall 45 is located closer to the bottom wall 49 than the opening 40 a of the storage unit 41 in the longitudinal direction. According to this, compared to the configuration in which the fifth opening window and the sixth opening window are formed on the opening side of the upper wall portion, reduction in the strength of the storage portion 41 is suppressed. As a result, the battery case 40 is prevented from suppressing the expansion of the battery cell.

(First modification)
In the present embodiment, the example has been described in which the battery pack 30 has five battery cells, the first battery stack 30i is configured by three battery cells, and the second battery stack 30j is configured by two battery cells. However, the number of battery cells included in the assembled battery 30 is not limited to the above example, and the number of battery cells included in the battery stack is not limited to the above example.

  For example, as shown in FIG. 6, the assembled battery 30 may have four battery cells, two battery cells may constitute a first battery stack 30i, and two battery cells may constitute a second battery stack 30j. As shown in FIG. 7, the assembled battery 30 may have six battery cells, the first battery stack 30 i may be configured by three battery cells, and the second battery stack 30 j may be configured by three battery cells. In this case, the assembled battery 30 has a sixth battery cell 36. Furthermore, although not shown, the assembled battery 30 may have one battery stack or may have three or more battery stacks. The battery stack may also have four or more battery cells.

(Second modification)
In the present embodiment, the configuration in which the communication window is not formed in the partition wall portion 50 is shown. However, as shown in FIG. 8, the first communication window 52 for communication may be formed in the partition wall 50. According to this, it is suppressed that heat is accumulated between the first battery stack 30i and the second battery stack 30j, and the heat is easily dissipated. The opening areas of the plurality of first communication windows 52 may be increased from the lower side to the upper side in the height direction according to the size relationship of the opening areas of the respective opening windows. Alternatively, the opening areas of the plurality of first communication windows 52 may be appropriately determined without depending on the size relationship of the opening areas of the respective opening windows. The open areas of the plurality of first communication windows may be equal or different.

(Third modification)
In the present embodiment, an example in which the first opening window 61 and the second opening window 62 are formed in the lower wall portion 46 located on the lower side in the height direction of the storage portion 41 is shown. However, as shown in FIG. 9, it is also possible to adopt a configuration in which the lower window 46 is not formed with the opening window.

  As shown in FIG. 9, the housing 11 is connected to the body of the vehicle. Therefore, the lower wall portion 46 is disposed to face the body of the vehicle via the housing 11, and the heat of the body of the vehicle is likely to be transferred via air or the like. On the other hand, by not forming the opening window in the lower wall portion 46 as described above, the heat transfer from the heat of the vehicle body to the battery cell is suppressed.

(The 4th modification)
In the present embodiment, an example is shown in which the fifth opening window 65 and the sixth opening window 66 are formed in the upper wall 45 positioned on the upper side in the height direction of the storage unit 41. However, as shown in FIG. 10, a configuration in which the opening window is not formed in the upper wall 45 may be employed.

(Fifth modification)
In the present embodiment, the third opening window 63 corresponding to each of the three battery cells constituting the first battery stack 30i and the second corresponding to each of the two battery cells constituting the second battery stack 30j are provided in the bottom wall portion 49. An example is shown in which four opening windows 64 are formed.

  However, as shown in FIG. 11, it is also possible to adopt a configuration in which the opening window corresponding to each battery cell is formed in the bottom wall 49. In the modification shown in FIG. 11, the seventh opening window 63a corresponding to the first battery cell 31, the tenth opening window 63b corresponding to the fourth battery cell 34, and the eleventh opening window 63c corresponding to the fifth battery cell 35 have The bottom wall 49 is formed. An eighth opening window 64 a corresponding to the second battery cell 32 and a ninth opening window 64 b corresponding to the third battery cell 33 are formed in the bottom wall 49.

  According to this, it is suppressed that the intensity | strength of the accommodating part 41 becomes low compared with the structure in which the big opening window corresponding to each battery cell was formed in the bottom wall part. As a result, the battery case 40 is prevented from suppressing the expansion of the battery cell.

  Moreover, in the modification shown in FIG. 11, multiple opening windows corresponding to each battery cell are formed. Each of the five types of opening windows corresponding to the five battery cells described above is formed in the three bottom wall portions 49. In FIG. 11, the portions exposed to the outside from the opening window formed in the bottom wall 49 of the battery cell are hatched.

  According to this, compared to the configuration in which one opening window corresponding to one battery cell is formed in the bottom wall portion, reduction in strength of the storage portion 41 is suppressed. Therefore, it is suppressed that the battery case 40 suppresses the expansion of the battery cell.

  Further, in the modification shown in FIG. 11, the opening areas of the plurality of opening windows corresponding to the respective battery cells decrease with distance from the geometric center GC1 of the corresponding battery cell along the lateral direction. In FIG. 11, only the geometric center GC1 of the first battery cell 31 is shown. Three seventh opening windows 63 a corresponding to the first battery cells 31 are laterally aligned in the bottom wall 49. The open area of one seventh open window 63a located at this geometric center GC1 is larger than the open areas of the two seventh open windows 63a located laterally away from the geometric center GC1. There is.

  The temperature distribution of a single battery cell generally decreases from the center to the end. On the other hand, as described above, the opening areas of the plurality of opening windows corresponding to one battery cell are reduced from the geometric center GC1 of the battery cell toward the outside thereof. According to this, equalization of temperature distribution in a battery cell can be attained.

(Sixth modification)
In the present embodiment, as shown in column (a) of FIG. 12, all of the fifth opening window 65 and the sixth opening window 66 are all on the bottom wall 49 side in the longitudinal direction with respect to the center line CL of the storage portion 41. An example is shown. However, as shown in the column (b) of FIG. 12, a configuration is adopted in which a part of each of the fifth opening window 65 and the sixth opening window 66 is located closer to the bottom wall 49 in the longitudinal direction than the center line CL. It can also be done.

(Seventh modified example)
In the present embodiment, an example is shown in which one fifth opening window 65 and one sixth opening window 66 are formed in the upper wall 45. However, as shown in FIG. 13, a plurality of fifth opening windows 65 and a plurality of sixth opening windows 66 may be formed in the upper wall 45. According to this, it is suppressed that the intensity | strength of the accommodating part 41 becomes low. Therefore, it is suppressed that the battery case 40 suppresses the expansion of the battery cell.

  Further, in the modification shown in FIG. 13, the opening areas of the plurality of opening windows corresponding to the respective battery cells decrease with distance from the geometric center GC1 of the corresponding battery cell along the lateral direction. In FIG. 13, only the geometric center GC1 of the fifth battery cell 35 is shown. Three fifth opening windows 65 corresponding to the fifth battery cell 35 are aligned in the lateral direction in the upper wall 45. The opening area of one fifth opening window 65 located on the geometric center GC1 side is larger than the opening area of each of the two fifth opening windows 65 located laterally away from the geometric center GC1. ing. According to this, equalization of temperature distribution in the 5th battery cell 35 can be attained. Similarly, the temperature distribution in the third battery cell 33 can be equalized.

Eighth Modified Example
Due to the difference in the number of battery cells, the first battery stack 30i tends to have a higher calorific value than the second battery stack 30j. Therefore, the opening area of the opening window corresponding to the battery cell of the first battery stack 30i may be larger than the opening area of the opening window corresponding to the battery cell of the second battery stack 30j. This suppresses the occurrence of temperature variations between the battery cells of the first battery stack 30i and the battery cells of the second battery stack 30j. As a result, the occurrence of variations in the life of the plurality of battery cells of the battery pack 30 is suppressed.

(The 9th modification)
In the present embodiment, an example is shown in which the opening area of the opening window corresponding to each battery cell increases as going from the battery cell located on the lower side in the height direction to the battery cell located on the upper side. However, the configuration is not limited to this, and for example, a configuration may be adopted in which the opening area of the opening window is increased as going from the battery cell located on the lower side in the height direction to the battery cell located on the upper side. This also suppresses the occurrence of temperature variations in the battery cells arranged in the vertical direction.

Second Embodiment
Next, a second embodiment will be described based on FIG. The battery pack according to each embodiment described below has many points in common with those according to the above-described embodiment. Therefore, in the following, the description of the common parts will be omitted, and the different parts will be mainly described. In the following, the same reference numerals are given to the same elements as the elements shown in the above-described embodiment.

  In the first embodiment, an example in which a plurality of battery cells are arranged in the height direction has been described. On the other hand, in the present embodiment, a plurality of battery cells are arranged in the lateral direction.

  The battery assembly 30 of the present embodiment has one first battery stack 30i. The first battery stack 30i has four battery cells. The first to fourth battery cells 31 to 34 are arranged in order in the lateral direction. The second main surfaces 30b of the first battery cell 31 and the second battery cell 32 respectively face each other in the lateral direction. The first main surfaces 30a of the second battery cells 32 and the third battery cells 33 respectively face each other in the lateral direction. The second main surfaces 30 b of the third battery cell 33 and the fourth battery cell 34 respectively face each other in the lateral direction. Thereby, the positive electrode terminals 30g and the negative electrode terminals 30h are alternately arranged in the lateral direction. The four battery cells are accommodated in the battery case 40 in the arrangement described above. Of course, the assembled battery 30 may have the fifth battery cell 35 or the sixth battery cell 36 described in the first embodiment.

  The storage portion 41 of the battery case 40 has three partition walls 51. The three partition walls 51 extend in the longitudinal direction to connect the upper wall 45 and the lower wall 46. The three partition walls 51 are located between the first side wall 47 and the second side wall 48 in the lateral direction. Thus, the storage unit 41 is divided into four storage spaces. These four storage spaces are arranged side by side. Specifically, the first storage space 41 c to the fourth storage space 41 f corresponding to the first battery cell 31 to the fourth battery cell 34 are arranged in order in the lateral direction.

  As shown in FIG. 14, an opening window corresponding to the first storage space 41 c to the fourth storage space 41 f is formed in the storage portion 41. In other words, an opening window corresponding to the first battery cell 31 to the fourth battery cell 34 is formed in the storage portion 41.

  As shown in columns (a) and (c) of FIG. 14, four lower opening windows 53 are formed in the lower wall portion 46. Each of the four lower opening windows 53 is formed in a portion of the lower wall portion 46 that constitutes each of the first storage space 41 c to the fourth storage space 41 f.

  As shown in columns (a) and (c) of FIG. 14, four upper opening windows 54 are formed in the upper wall portion 45. Each of the four upper opening windows 54 is formed in a portion of the upper wall portion 45 that constitutes each of the first storage space 41 c to the fourth storage space 41 f.

  As shown in columns (a) and (b) of FIG. 14, one bottom opening window 55 is formed in the bottom wall 49. The bottom opening window 55 is formed in a portion of the bottom wall 49 that constitutes each of the first storage space 41 c to the fourth storage space 41 f. As described above, the bottom opening windows 55 correspond to the first battery cell 31 to the fourth battery cell 34 in common. In FIG. 14, the portions of the battery cell exposed to the outside from the bottom opening window 55 are hatched.

  Most of the bottom opening window 55 is a reference line BL orthogonal to the horizontal and vertical directions of the geometric center GC2 of the first battery stack 30i shown by broken lines in (a) to (c) of FIG. It is formed on the upper wall 45 side. In other words, the opening area of the upper portion in the height direction is larger than the opening area of the lower portion of the bottom opening window 55 in the height direction below the reference line BL. The position in the height direction of the geometric center GC2 of the first battery stack 30i is equal to the position in the height direction of the geometric center of each of the four battery cells. Therefore, reference line BL is also a line passing through the geometric center of the battery cell.

  According to this, when the vehicle is at rest in the horizontal plane, the plurality of battery cells are arranged in the horizontal direction. And the opening window corresponding to these some battery cells is formed in the accommodating part 41. As shown in FIG. Therefore, the heat dissipation of the plurality of battery cells with respect to the temperature distribution in the vertical direction is equalized.

  Further, the opening area of the upper side portion in the height direction is larger than the opening area of the lower side portion of the bottom opening window 55 in the height direction than the reference line BL. Therefore, the heat dissipation in the upper side in the vertical direction in the first battery stack 30i can be higher than the heat dissipation in the lower side in the vertical direction. Therefore, the temperature distribution in the first battery stack 30i can be equalized. That is, the temperature distribution in the battery cell can be equalized. Thus, the occurrence of variations in the life of the plurality of battery cells is suppressed.

(Tenth modification)
In the present embodiment, the configuration in which the opening window is not formed in the partition wall 51 is shown. However, as shown in FIG. 15, a second communication window 56 for communication may be formed in the partition wall 51. According to this, it is suppressed that heat is accumulated between the battery cells arranged in the lateral direction, and the heat is easily dissipated. Although two partition walls 51 located between two battery cells are shown in FIG. 15, it is needless to say that one partition wall 51 may be located between two battery cells. Furthermore, the storage portion 41 may not have the partition wall portion 51. In this case, the battery cells may be arranged in the lateral direction via the spacer.

(Eleventh modified example)
In the present embodiment, an example in which the four lower opening windows 53 are formed in the lower wall portion 46 is shown. However, as shown in FIG. 16, a configuration in which the lower window 46 is not formed may be employed.

(Twelfth modified example)
In the present embodiment, an example in which four upper opening windows 54 are formed in the upper wall 45 is shown. However, as shown in FIG. 17, a configuration in which the opening window is not formed in the upper wall 45 may be employed.

(The 13th modification)
As shown in FIG. 18, it is also possible to adopt a configuration in which the first battery stack 30i and the second battery stack 30j are laterally aligned. In this case, the storage portion 41 has a dividing wall portion 50 extending in the lateral direction and connecting the upper wall portion 45 and the lower wall portion 46. A configuration in which the first communication window 52 is formed in the partition wall 50 can also be adopted.

  According to this, it is suppressed that heat is accumulated between the first battery stack 30i and the second battery stack 30j, and the heat is easily dissipated.

  Although the preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments and can be variously modified and implemented without departing from the spirit of the present disclosure. It is.

(Other modifications)
In the present embodiment, an example is shown in which the vehicle equipped with the power supply system has an idle stop function. However, the vehicle equipped with the power supply system is not limited to the above example. For example, a hybrid car or an electric car can be adopted. In this case, the starter motor and the rotating electrical machine shown in the present embodiment replace the motor generator.

DESCRIPTION OF REFERENCE NUMERALS 10 case 11 housing 11 a flange 12 cover 13 bottom wall 30i first battery stack 30 j second battery stack 11 first battery cell 32 second battery cell 33 third battery cell 34 fourth battery cell 35 fifth battery cell 36 sixth battery cell 40 battery case 40a opening 41a first stack storage space 41b second Stack storage space, 45: upper wall, 46: lower wall, 49: bottom wall, 50: partition wall, 52: first communication window, 53: lower opening window, 54: upper opening window, 55: bottom Opening window 56: second communication window 61: first opening window 62: second opening window 63: third opening window 63a: seventh opening window 63b: tenth opening window 63c: eleventh opening Window 64: fourth opening window 64a: eighth opening window 64b: ninth opening window 65: fifth opening Window, 66 ... sixth open window, 100 ... battery pack, GC1, GC2 ... geometric center

Claims (16)

With multiple battery cells (31 to 36),
A battery case (40) for storing a battery stack (30i, 30j) in which a plurality of the battery cells are arranged in the vertical direction;
A plurality of opening windows (55, 61 to 66, 63a to 63c, 64a, 64b) corresponding to a plurality of the battery cells are formed in the battery case,
A battery pack, wherein the opening areas of the plurality of the opening windows corresponding to the plurality of battery cells increase from the battery cells located on the lower side in the vertical direction to the battery cells located on the upper side.   The upper window (45) on the upper side in the vertical direction of the battery case is formed with the opening window (65, 66) corresponding to the battery cell facing the upper wall in the vertical direction The battery pack according to Item 1.   The battery pack according to claim 2, wherein a plurality of the opening windows are formed in the upper wall portion.   The opening area of the plurality of opening windows formed in the upper wall portion is a horizontal direction perpendicular to the vertical direction from the geometric center (GC1) of the battery cell that is opposed to the upper wall portion in the vertical direction The battery pack according to claim 3, which becomes smaller as it goes away. In the battery case, an opening (40a) for inserting the battery cell inside is formed in such a manner as to open in the vertical direction of the horizontal direction orthogonal to the vertical direction,
The battery case has a bottom wall (49) aligned with the opening in the longitudinal direction,
The at least one part of the said opening window formed in the said upper wall part of the said battery case is located in the said bottom wall part side rather than the said opening part in the said longitudinal direction. Battery pack. In the battery case, an opening (40a) for inserting the battery cell inside is formed in such a manner as to open in the vertical direction of the horizontal direction orthogonal to the vertical direction,
The battery case has a bottom wall (49) aligned with the opening in the longitudinal direction,
The battery pack according to any one of claims 1 to 5, wherein at least a part of the plurality of the opening windows is formed in the bottom wall portion.   The battery pack according to claim 6, wherein a plurality of the opening windows corresponding to one battery cell are formed in the bottom wall portion.   The opening area of the plurality of opening windows corresponding to one battery cell formed in the bottom wall portion is the longitudinal direction of the horizontal direction from the geometric center (GC1) of the corresponding battery cell. The battery pack according to claim 7, wherein the battery pack decreases with distance along a lateral direction orthogonal to the angle. It has a housing (11) attached to the body of the vehicle while housing the battery case,
A connection portion (11a) with the body is formed at the bottom of the housing,
A lower lower wall (46) in the vertical direction in the battery case faces the bottom (13) of the housing,
The battery pack according to any one of claims 1 to 8, wherein a plurality of the opening windows are formed in a wall portion other than the lower wall portion in the battery case. A plurality of the battery stacks having different numbers of the battery cells arranged in the vertical direction;
Assuming that one of the plurality of battery stacks is a first battery stack (30i), and one having a smaller number of battery cells aligned in the vertical direction than the first battery stack is a second battery stack (30j),
The opening area of the opening window corresponding to the battery cell of the first battery stack is larger than the opening area of the opening window corresponding to the battery cell of the second battery stack. Battery pack as described in. Have multiple battery stacks,
A plurality of stack storage spaces (41a, 41b) for storing a plurality of the battery stacks are formed inside the battery case,
The battery case has a partition wall (50) for partitioning a plurality of the stack storage spaces,
The battery pack according to any one of claims 1 to 10, wherein a communication window (52) for communication is formed in the partition wall. With multiple battery cells (31 to 36),
A battery case (40) for storing a battery stack (30i, 30j) in which a plurality of the battery cells are arranged horizontally in the horizontal direction;
Opening windows (55, 66, 66, 63a, 63a, 64a, 64b) corresponding to the battery stack are formed in the battery case,
The opening area of the opening window is higher in the vertical direction from the geometric center of the battery stack than in the vertical direction orthogonal to the horizontal direction from the geometric center (GC2) of the battery stack. Big battery pack. In the battery case, an opening (40a) for inserting the battery cell inside is formed in such a manner as to open in a vertical direction orthogonal to the horizontal direction in the horizontal direction,
The battery case has a bottom wall (49) aligned with the opening in the longitudinal direction,
The battery pack according to claim 12, wherein the opening window is formed in the bottom wall portion to correspond in common to each of the plurality of battery cells.   The battery pack according to claim 13, wherein an upper opening window (54) different from the opening window is formed in the upper upper wall (45) in the upper side in the vertical direction of the battery case.   The battery pack according to any one of claims 12 to 14, wherein a lower opening window (53) different from the opening window is formed in the lower wall (46) at the lower side in the vertical direction of the battery case. Have multiple battery stacks,
A plurality of stack storage spaces (41a, 41b) for storing a plurality of the battery stacks are formed inside the battery case,
The battery case has a partition wall (50) for partitioning the plurality of stack storage spaces,
The battery pack according to any one of claims 12 to 15, wherein a communication window (52) for communication is formed in the partition wall.

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