Battery pack and manufacturing method thereof

Abstract

This battery pack is formed by tightly binding a plurality of laminated batteries by means of a holding member and placing the same on a placement target. At least a battery bottom surface of each of the plurality of batteries is covered with an insulating member. The battery bottom surface is disposed to face the placement target side. The holding member has: end members disposed on both ends in the battery lamination direction; and side members that are connected to the end members and that surround the plurality of batteries together with the end members. The end members have, on the placement target side: first regions constituting main sections; and second regions formed on first leg parts and protruding to the placement target side with respect to the first regions and the battery bottom surfaces. The end members have the second regions disposed on both sides of the first regions. Spacers that are disposed between the plurality of laminated batteries have, on the placement target side: third regions; and fourth regions formed on second leg parts and protruding to the placement target side with respect to the third regions and the battery bottom surfaces.

Description

[Technical Field]

[0001] The present invention relates to a battery pack including a plurality of battery cells and a method for manufacturing the same. [Background technology]

[0002] Conventionally, there has been known a battery assembly comprising a plurality of battery cells and a fixing member for fastening the battery stack formed by stacking the battery cells (Patent Document 1). In such a battery assembly, the battery cell outer can is made of metal, and the outer can is sometimes covered with an insulating film to prevent short circuits due to condensation or the like. In general, in a battery assembly comprising a plurality of battery cells, the insulating film covering the bottom surface of the battery cells is easily damaged during the manufacturing process.

[0003] To address this issue, conventional battery packs have adopted a structure in which the lower ends of the plates that support the multiple battery cells from both sides in the stacking direction protrude below the bottom surface of the battery cells. This structure prevents the work table and the bottom surfaces of the battery cells from coming into contact during the manufacturing process, thereby preventing damage to the insulating film that covers the bottom surfaces of the battery cells. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] WO2020 / 066060 publication Summary of the Invention [Problem to be solved by the invention]

[0005] However, in a battery pack with the above structure, multiple plates supporting the battery cells from both sides in the stacking direction are interposed between the cooling plate and the battery cells, leaving room for improvement in the cooling performance of the battery cells.

[0006] The present invention has been made in view of the above points, and provides a battery pack that can prevent film tearing during the manufacturing process while also improving cooling efficiency. [Means for solving the problem]

[0007] The present invention, which solves the problem, is a battery pack in which a plurality of stacked batteries are fastened with a holding member and placed on a mounting object, wherein each of the plurality of batteries has a storage element housed in a battery container having a bottom surface, at least the bottom surface is covered with an insulating member, and the bottom surface is arranged facing the mounting object, the holding member has end members arranged at both ends of the batteries in the stacking direction, and the end members have, on the mounting object side, a first region and a second region formed to protrude toward the mounting object further than the first region and the bottom surface. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a battery pack that can prevent film tearing during the manufacturing process and also improve cooling efficiency. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective view showing an outline of a battery pack according to an embodiment of the present invention; [Figure 2] 2 is a bottom view of a battery module that constitutes the battery pack shown in FIG. 1. FIG. [Figure 3] FIG. 3 is a perspective view of a battery cell (referred to as a "battery" in the present invention) that constitutes the battery module whose bottom surface is shown in FIG. [Figure 4] FIG. 10 is a perspective view schematically showing a battery pack according to another embodiment of the present invention. [Figure 5A] 5 is a bottom view of a battery module that constitutes the battery pack shown in FIG. 4. FIG. [Figure 5B] 1 shows a front view of the end member 30 as seen from the stacking direction, and a right side view of the end member 30 as seen from the width direction. [Figure 6] FIG. 10 is a perspective view showing an outline of a battery pack according to still another embodiment. [Figure 7] 10A and 10B are perspective views showing a method for manufacturing a battery pack according to still another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of a battery pack according to the present invention will be described with reference to the drawings. The battery pack is installed in a vehicle such as an electric vehicle (EV) or a hybrid electric vehicle (HEV). In addition, parts having the same effect are designated by the same reference numerals throughout the drawings to avoid duplication of explanation.

[0011] A battery pack 100 according to an embodiment is shown in Figures 1 to 3 (also see Figures 4 to 7 as appropriate). Another embodiment of the battery pack 100A is shown in Figures 4 and 5, yet another embodiment of the battery pack 100B is shown in Figure 6, and yet another embodiment of the battery pack 100C is shown in Figure 7. When it is not necessary to distinguish between the battery packs 100, 100A to 100C, they are collectively referred to as the battery pack 100.

[0012] Fig. 1 is a perspective view of a battery pack 100. Fig. 2 is a bottom view of a battery module 90 that constitutes the battery pack 100 shown in Fig. 1. Fig. 3 is a perspective view of a battery cell 10 that constitutes the battery module 90, the bottom of which is shown in Fig. 2. As shown in Fig. 3, the battery cell 10 has, for example, a battery can 11, a battery lid 12, and a pair of external terminals 13.

[0013] The storage element constituting the battery cell 10 is an element that has at least a pair of positive and negative electrodes and an electrochemically reactive material (electrolyte) interposed between the electrodes and is capable of storing electricity. More specific examples of storage elements include secondary batteries such as lithium-ion batteries, as well as electrolytic capacitors that can store large amounts of electricity. A single component containing storage elements is referred to as a battery cell 10 or simply a battery 10.

[0014] Here, a lithium-ion battery is exemplified as the battery cell 10. The battery can 11 is a rectangular cylindrical container with a bottom and an opening at one end in the height direction. The battery lid 12 is a roughly rectangular plate-like member that closes the opening of the battery can 11. The battery can 11 and the battery lid 12 are made of a metal material. Examples of the metal material include aluminum and aluminum alloys.

[0015] Although not shown, a storage element covered with an insulating sheet is housed inside the battery can 11. The storage element is formed, for example, by overlapping and winding a strip-shaped positive electrode and a strip-shaped negative electrode with a strip-shaped separator interposed therebetween. The battery can 11 housing the storage element has a battery lid 12 laser-welded around the entire periphery of an opening provided at the top end of the battery can 11, thereby sealing it.

[0016] The battery lid 12 has through holes at both longitudinal ends for inserting a pair of external terminals 13, and a gas release valve 15 and a liquid injection hole 16 at its longitudinal middle. The external terminals 13 are roughly rectangular block-shaped and are placed on the outer surface of the battery lid 12, i.e., on the top surface 10t of the battery cell 10, via an electrically insulating gasket 14.

[0017] Although not shown in the figure, the external terminal 13 has a columnar or cylindrical connecting portion that extends from the bottom surface facing the battery lid 12 in a direction penetrating the battery lid 12. Of the pair of external terminals 13, one external terminal 13 is a positive external terminal 13 connected to the positive electrode of the electricity storage element via a positive current collector plate in the battery can 11, and the other external terminal 13 is a negative external terminal 13 connected to the negative electrode of the electricity storage element via a negative current collector plate in the battery can 11.

[0018] The gas release valve 15 is, for example, a portion of the battery lid 12 that has been thinned by pressing to form a slit. The gas release valve 15 opens when the internal pressure of the battery cell 10 rises to a predetermined pressure, releasing the gas inside the battery cell 10 and reducing the internal pressure of the battery cell 10 to ensure safety.

[0019] The liquid filling hole 16 is provided for injecting an electrolyte into the battery can 11, and after the electrolyte is injected, the liquid filling hole 16 is sealed by joining a liquid filling plug 17 by, for example, laser welding. The electrolyte to be injected into the battery can 11 may be, for example, a non-aqueous electrolyte in which a lithium salt such as lithium hexafluorophosphate (LiPF6) is dissolved in a carbonate ester-based organic solvent such as ethylene carbonate.

[0020] The battery pack 100 stores power supplied via a pair of input / output terminals 91 in the battery cells 10. The power stored in the battery cells 10 is supplied to an electric device such as a vehicle motor via the input / output terminals 91. The battery pack 100 includes a plurality of flat battery cells 10, a plurality of cell holders 20, a plurality of plates (also referred to as "end members" or "end blocks") 30 (FIGS. 1, 2, 4 to 7), an insulating layer 40 (FIG. 3), a heat conduction sheet 50 (FIGS. 1 and 4), and a cooling section 60 (FIGS. 1 and 4).

[0021] Fig. 4 is a perspective view showing a schematic diagram of the battery pack 100A. The cell holders 20 will now be described. As shown in Fig. 4, the cell holders 20 are stacked in the same number as the battery cells 10 in order to support the battery cells 10. The cell holders 20 include end cell holders 20E and intermediate cell holders 20M, which are collectively referred to as end cell holders 20E and intermediate cell holders 20M.

[0022] The end cell holders 20E are disposed at both ends of the stack. The middle cell holder 20M is disposed in the middle of the stack. In this way, multiple cell holders 20 with different shapes depending on their position hold each individual battery cell 10 from both sides in the thickness direction Dt, stacking them in the thickness direction Dt.

[0023] The multiple plates 30 support the multiple battery cells 10 from both sides in the stacking direction (thickness direction Dt) via cell holders 20E. The insulating layer 40 is provided over the entire bottom surface 10b of each battery cell 10 (FIG. 3).

[0024] The thermally conductive sheet 50 contacts the lower surface 40a (FIG. 4) of the insulating layer 40. The cooling unit 60 cools the multiple battery cells 10 via the thermally conductive sheet 50. The leg portions 30a (FIGS. 1, 2, 4, and 5A) of the plate (end member) 30 protrude downward below the lower surface 40a of the insulating layer 40 of the cell film shown in FIG.

[0025] The cell holder 20 has a flat portion and support claws (not shown) that protrude from the flat portion and are bent to support the side surfaces of the battery cells 10. The cell holder 20 defines an opening other than the flat portion and the support claws. The opening exposes the entire lower surface 40a of the insulating layer 40 to the thermally conductive sheet 50.

[0026] The cell holder 20 is made of a resin material such as engineering plastics, such as polybutylene terephthalate (PBT) or polycarbonate (PC), or rubber. The cell holder 20 holds each battery cell 10 by sandwiching it from both sides in the thickness direction Dt.

[0027] The lower end of the cell holder 20 and the lower surface 40a of the insulating layer 40 covering the bottom surface 10b of the battery cell 10 are, for example, at roughly the same position in the height direction Dh (FIG. 3) of the battery cell 10. The cell holder 20 has an opening that exposes the entire lower surface 40a of the insulating layer 40 provided on the bottom surface 10b of the battery cell 10 to the thermal conduction sheet 50.

[0028] The multiple cell holders 20 include, for example, multiple intermediate cell holders 20M and multiple end cell holders 20E. The intermediate cell holders 20M are interposed between two adjacent battery cells 10 of the multiple battery cells 10 stacked in the thickness direction Dt. The end cell holders 20E are disposed at both ends in the stacking direction (thickness direction Dt) of the multiple battery cells 10 stacked with the intermediate cell holders 20M interposed therebetween.

[0029] Unlike the other cell holders 20, the end cell holder 20E alone has a fixing portion 23 (FIG. 4) for fixing, for example, the input / output cable 101 (FIG. 1) of the battery pack 100. The fixing portion 23 is provided, for example, to protrude toward the plate 30. The fixing portion 23 has, for example, a nut 23a or a bolt for fixing the input / output cable 101 insert-molded therein.

[0030] The plates 30 are, for example, rectangular metal members, and are a pair of end plates arranged at both ends in the stacking direction of the multiple battery cells 10. As shown in Fig. 1, the pair of plates 30 have legs 30a and support the multiple battery cells 10 via the cell holders 20 from both sides in the stacking direction, i.e., the thickness direction Dt of the battery cells 10.

[0031] The leg portions 30a (FIGS. 1, 2, 4, and 5A) of the plate 30 protrude downward from the lower surface 40a of the insulating layer 40. The leg portions 30a of the plate 30 are in contact with the upper surface of the cooling unit 60 via, for example, a thermally conductive sheet 50, and are supported by the upper surface of the cooling unit 60.

[0032] The distance between the lower surface 40a of the insulating layer 40 and the cooling section 60 in the height direction Dh of the battery cell 10, i.e., the protrusion height, which is the distance from the lower surface 40a of the insulating layer 40 (Figure 3) to the leg portion 30a of the plate 30, can be, for example, 0.1 mm or more and 3.0 mm or less.

[0033] The plate 30 has, for example, a recess (not shown) that receives the fixing portion 23 of the end cell holder 20E. The fixing portion 23 of the end cell holder 20E is received in the recess of the plate 30. In this way, the plate 30 can support and reinforce the fixing portion 23 while fastening the input / output cable 101 to the fixing portion 23.

[0034] Region A (FIG. 2) on the mounting surface side of the plate 30, excluding the legs 32a, is an example of the claimed first region, and is the main region that makes up the majority of the mounting surface side. In contrast, region B, where the legs 30a are present and including the ends of the legs 30a that face the mounting surface, is an example of the claimed second region. It is more preferable that region A be located at the same level as or above the lower surface 40a of the insulating layer 40. The protrusion height, which is the distance from the lower surface 40a of the insulating layer 40 to region A of the plate 30 in the height direction Dh of the battery cell 10, can be, for example, 0 mm or more and 15 mm or less.

[0035] This prevents the plate 30 from coming into contact with the cooling section 60, and prevents excessive cooling of the battery cells 10 located at the edge due to heat being absorbed by the plate 30. As a result, it is possible to suppress temperature variations among the battery cells throughout the battery pack 100. The legs 30a of the plate 30 are preferably tapered and have chamfered tips to prevent injury during handling or contact.

[0036] The insulating layer 40 completely covers at least the contact surfaces of the bottom surfaces 10b of the individual battery cells 10. The insulating layer 40 can be formed, for example, from an electrically insulating film or coating. The insulating layer 40 can be made of an electrically insulating resin material such as polyethylene terephthalate (PET) or a rubber film.

[0037] The insulating layer 40 may be provided on some or all of the side surfaces of the battery cell 10, including the wide side surface 10w and the narrow side surface 10n (Figure 3), as long as it is provided on at least the entire bottom surface 10b of the battery cell 10, or may be provided on the entire outer surface of the battery cell 10 excluding the external terminals 13.

[0038] The cooling unit 60 is, for example, a rectangular flat metal member, and includes a refrigerant flow path through which a refrigerant flows. The cooling unit 60 has, for example, screw holes 61 for fastening bolts 80. The cooling unit 60 may be part of the housing of the battery pack 100.

[0039] The side plate 70 is, for example, a rectangular flat metal member. The side plate 70 is shaped like a rectangular plate with the stacking direction of the multiple battery cells 10 as the longitudinal direction and the height direction Dh of the battery cells 10 as the transverse direction.

[0040] A pair of side plates 70 are arranged on both sides of the plurality of battery cells 10 in the width direction Dw (FIG. 3), and face the narrow side surfaces 10n of the plurality of battery cells 10 via the sides of the cell holder 20.

[0041] The upper ends of the side plates 70 are bent toward the center of the width direction Dw of the battery cells 10 and engage with the upper side edges of the multiple cell holders 20. The lower ends of the side plates 70 extend along the height direction Dh of the battery cells 10 and engage with the lower side edges of the multiple cell holders 20.

[0042] Both longitudinal ends of the side plate 70 have through holes for inserting bolts 71. The side plate 70 is fixed to a pair of plates 30 arranged at both ends in the stacking direction of the multiple battery cells 10 by fastening the bolts 71 inserted into the through holes at both ends into the screw holes 32 in the plates 30.

[0043] This defines the spacing between the pair of plates 30, and each of the multiple battery cells 10 is compressed and held within a predetermined range between the cell holders 20. Note that the method of fixing the side plates 70 to the plate 30 is not limited to bolts 71, and the side plates 70 may also be fixed to the plate 30 by rivets, crimping, welding, or the like.

[0044] 1 and 2, the end member 30 has a fixing portion 300 that bulges outward in a rectangular shape from the outside of the first and second regions A and B in the stacking direction and fixes the battery pack 100 to the mounting surface. A bolt 80 (FIG. 1, etc.) serving as a fastening means is inserted into a through hole 33 of the fixing portion 300 and fastened to a screw hole 61 of the cooling portion 60. As a result, the thermally conductive sheet 50 is compressed between the lower end portion 20b of the cell holder 20, the lower surface 40a of the insulating layer 40, and the cooling portion 60, and is pressed against and in contact with the lower surface 40a of the insulating layer 40 and the upper surface 60a of the cooling portion 60.

[0045] The battery module 90 includes, for example, a plurality of battery cells 10, a plurality of cell holders 20, a pair of plates 30, an insulating layer 40 provided on the bottom surface 10b of each battery cell 10, and a pair of side plates 70.

[0046] The battery module 90 also includes multiple bus bars 91. The bus bars 91 are conductive metal plate-shaped members, and include an intermediate bus bar 91M that connects multiple battery cells 10 in series, and end bus bars 91E that connect the multiple battery cells 10 connected in series to the input / output cable 101.

[0047] In the battery module 90, the multiple battery cells 10 are stacked in the thickness direction Dt with the positions of the positive electrode external terminals 13 and the negative electrode external terminals 13 alternately reversed.

[0048] The positive external terminal 13 of one battery cell 10 and the negative external terminal 13 of the other battery cell 10 that are adjacent in the stacking direction (thickness direction Dt) are sequentially connected by an intermediate bus bar 91M, thereby connecting multiple battery cells 10 in series.

[0049] A pair of end bus bars 91E connected to the positive external terminal 13 of the battery cell 10 and the negative external terminal 13 of the battery cell 10 at the other end in the stacking direction are each connected to an input / output cable 101. The input / output cable 101 is connected to the end bus bar 91E, for example, by inserting a bolt 92 inserted into the terminal portion at the end of the input / output cable 101 into the through-hole of the end bus bar 91E and fastening it to a nut 23a of the fixing portion 23 of the end cell holder 20E.

[0050] The following describes the operation of the battery pack 100. As described above, the battery pack 100 includes a plurality of flat battery cells 10 and a plurality of cell holders 20 that hold the individual battery cells 10 from both sides in the thickness direction Dt and stack them in the thickness direction Dt.

[0051] The battery pack 100 also includes a plurality of plates 30 that support the plurality of battery cells 10 from both sides in the stacking direction via the cell holders 20, and an insulating layer 40 that is provided over the entire bottom surface 10b of the battery cell 10.

[0052] Furthermore, the battery pack 100 includes a heat conductive sheet 50 in contact with the lower surface of the insulating layer 40 , and a cooling unit 60 that cools the plurality of battery cells 10 via the heat conductive sheet 50 .

[0053] The legs (first legs) 30a of the plate 30 protrude downward below the lower surface 40a of the insulating layer 40. The cell holder 20 also has support claws that support the side surfaces of the battery cells 10 and openings that expose the entire lower surface 40a of the insulating layer 40 to the thermal conduction sheet 50.

[0054] With this configuration, during the manufacturing process of the battery pack 100, for example, when the battery module 90 is placed on a support surface such as a workbench, the legs 30a of the multiple plates 30 that support the multiple battery cells 10 from both sides in the stacking direction via the cell holders 20 are supported by the support surface.

[0055] Furthermore, since the leg portions 30a of the plate 30 protrude downward from the lower surface 40a of the insulating layer 40, a space is formed between the lower surface 40a of the insulating layer 40 and the support surface that supports the battery module 90.

[0056] Therefore, foreign matter present on the support surface is not pressed against the lower surface 40a of the insulating layer 40 provided on the bottom surface 10b of the battery cell 10, preventing damage to the insulating layer 40. This more reliably prevents short circuits via the bottom surface 10b of the battery cell 10, improving the safety of the battery pack 100.

[0057] Furthermore, as described above, the cell holder 20 has support claws that support the side surfaces of the battery cells 10. Therefore, by using the cell holder 20 to hold each individual battery cell 10 from both sides in the thickness direction Dt and stacking the battery cells 10 in the thickness direction Dt, the side surfaces of each individual battery cell 10 are supported by the support claws, and the battery cells 10 can be fixed to the cell holder 20.

[0058] This eliminates the need to support the bottom surface 10b of the battery cell 10 with the cell holder 20, and makes it possible to provide an opening that exposes the entire lower surface 40a of the insulating layer 40 that is provided over the entire bottom surface 10b of the battery cell 10.

[0059] The legs 30a of the plate 30 are located at both ends, and the lower surface 40a of the insulating layer 40 protrudes downward in the central space 120 that belongs to region A. Note that the battery cell 10 has current collectors below the pair of external terminals 13, and the winding group is located in the middle, so the winding group is located above the central space 120 via the battery can 11, and therefore cooling the central space 120 is efficient from the standpoint of cooling efficiency.

[0060] The cell holder 20 has an opening that exposes the entire underside 40a of the insulating layer 40 to the thermally conductive sheet 50, and the cooling unit 60 supports the bottom surface 10b of the cell via the thermally conductive sheet, making it possible to cool the entire bottom surface 10b of the battery cell 10 by the cooling unit 60.

[0061] This improves the cooling performance of the battery cells 10 compared to a conventional battery pack structure in which the cooling unit supports the plate. Furthermore, when the plate 30 and the cooling heat transfer unit are not in contact, the end battery cells 10E are prevented from being excessively cooled by the plate, and temperature variations among the battery cells in the entire battery pack can be suppressed.

[0062] In the battery pack 100, the distance between the cooling unit 60 and the lower surface 40a of the insulating layer 40 provided on the bottom surface 10b of the battery cell 10 is, for example, 0.1 mm or more and 3.0 mm or less. By making the distance 0.1 mm or more, it is possible to prevent discharge between the bottom surface 10b of the battery cell 10 and the cooling unit 60 even if holes or cracks occur in the lower surface 40a due to deterioration over time.

[0063] More specifically, the breakdown voltage of air is approximately 3 MV / mm. Therefore, by setting the gap to 0.1 mm or more, it is possible to prevent discharge in a battery pack 100 with a voltage of, for example, approximately 300 V. Furthermore, by setting the gap to 3.0 mm or less, it is possible to prevent the bottom surface 10b of the battery cell 10 from being separated from the cooling unit 60 more than necessary, thereby preventing a decrease in the cooling performance of the battery cell 10.

[0064] The battery pack 100 described above can prevent damage to the insulating layer 40 provided on the bottom surface 10b of the battery cell 10 as shown in FIG. 3, and also improves the cooling performance of the battery cell 10 compared to conventional methods, thereby equalizing the temperature difference between the cells.

[0065] The temperature difference problem in conventional battery packs was caused by the cooling section being in contact with the plate, which meant that the battery cells closest to the plate were overcooled compared to the other battery cells.

[0066] In this regard, in the battery pack 100, the cooling section 60 (FIGS. 1 and 4) is separated from the plate (end member, end block) 30 (FIGS. 1, 2, 4 to 7), which has improved the temperature difference that is unlikely to occur among the multiple battery cells 10 during cooling. Note that the battery pack 100 of the present invention is not limited to the above-mentioned configuration.

[0067] The plate 30 and the leg 30a may also be considered as a temporary assembly jig. The two are temporarily joined together with, for example, adhesive tape and bolts only during the manufacturing process where there is a possibility that the insulating layer 40 may be damaged and it is necessary to prevent this. In the next process, the leg 30d used as the temporary assembly jig is removed from the plate 30.

[0068] Once the legs 30a have completed their role of providing a gap between the battery pack 100A and the thermally conductive sheet 50, the battery pack 100A can be placed on the thermally conductive sheet 50 in close contact therewith.

[0069] As a result, the cell holder 20 has an opening that exposes the entire underside 40a (Figure 3) of the insulating layer 40 to the thermal conduction sheet 50, and the cooling unit 60 supports the bottom surface 10b of the cell via the thermal conduction sheet, making it possible to cool the entire bottom surface 10b (Figure 3) of the battery cell 10 by the cooling unit 60.

[0070] Fig. 5A is a bottom view of a battery module 90A constituting the battery pack 100A shown in Fig. 4. The battery pack 100A differs from the battery pack 100 shown in Fig. 1 in that the battery module 90A includes an intermediate plate (also referred to as a spacer) 30M in the center of the stacking direction of the battery cells 10. The other configuration of the battery pack 100A is similar to that of the battery pack 100 shown in Fig. 1, so similar parts are designated by the same reference numerals and description thereof will be omitted.

[0071] In the battery pack 100A, the leg portion (second leg portion) 30Ma of the intermediate plate 30M protrudes downward from the lower surface 40a of the insulating layer 40, similar to the leg portion 30a of the plate 30. Therefore, the battery pack 100A shown in Fig. 4 can also achieve the same effects as the battery pack 100 shown in Fig. 1.

[0072] 6 is a perspective view showing an outline of the battery pack 100B. The lower ends 70b of the side plates 70 are located below the lower surface 40a of the insulating layer. During the manufacturing process of the battery pack 100B, for example, when the battery module 90 is placed on a support surface such as a workbench, the lower ends 70b of the side plates 70, which support the multiple battery cells 10 from both sides in the stacking direction via the cell holders 20, are supported by the support surface.

[0073] Furthermore, because the lower ends 70b of the side plates 70 protrude below the lower surface 40a of the insulating layer 40, a space is formed between the lower surface 40a of the insulating layer 40 and the support surface that supports the battery module 90. Therefore, foreign matter present on the support surface will not be pressed against the lower surface 40a of the insulating layer 40 that is provided on the bottom surface 10b of the battery cell 10, preventing damage to the insulating layer 40.

[0074] The cell holder 20 has an opening that exposes the entire lower surface 40a of the insulating layer 40 to the thermally conductive sheet 50, and the cooling unit 60 supports the bottom surface 10b of the cell via the thermally conductive sheet, making it possible to cool the entire bottom surface 10b of the battery cell 10 by the cooling unit 60. This makes it possible to improve the cooling performance of the battery cell 10 compared to a structure in which the cooling unit supports a plate, as in conventional assembled batteries.

[0075] The distance between the lower surface 40a of the insulating layer 40 and the cooling section 60 in the height direction Dh of the battery cell 10, i.e., the protrusion height, which is the distance from the lower surface 40a of the insulating layer 40 to the lower end 70b of the side plate 70, can be, for example, 0.1 mm or more and 3.0 mm or less.

[0076] The lower end 70b of the side plate 70 may have the leg structure of the first leg portion 30a described in Figures 1 and 4, as long as a space is formed between the lower surface 40a of the insulating layer 40 and the support surface that supports the battery module 90 when the battery module 90 is placed on a support surface such as a workbench.

[0077] It is more preferable that the lower end 30c of the plate 30 is positioned at the same level as or above the lower surface 40a of the insulating layer 40. The protrusion height, which is the distance from the lower surface 40a of the insulating layer 40 to region A of the plate 30 in the height direction Dh of the battery cell 10, can be, for example, 0 mm or more and 15 mm or less.

[0078] This prevents the plate 30 from coming into contact with the cooling heat transfer portion, preventing the end battery cells 10E from being excessively cooled by the plate, and making it possible to suppress temperature variations among the battery cells throughout the battery pack.

[0079] 7 is a perspective view showing a manufacturing method of the battery pack 100C. During the manufacturing process of the battery pack 100C, for example, when the battery module 90 is placed on a support surface such as a workbench, the legs (referred to as "third legs" in the present invention) 30d of the multiple plates 30 that support the multiple battery cells 10 from both sides in the stacking direction via the cell holders 20 are supported by the support surface.

[0080] Furthermore, because the leg portions 30d of the plate 30 protrude below the lower surface 40a of the insulating layer 40, a space is formed between the lower surface 40a of the insulating layer 40 and the support surface that supports the battery module 90. This prevents foreign matter present on the support surface from being pressed against the lower surface 40a of the insulating layer 40 that is provided on the bottom surface 10b of the battery cell 10, preventing damage to the insulating layer 40. This more reliably prevents short circuits via the bottom surface 10b of the battery cell 10, improving the safety of the battery pack 100C.

[0081] It should be noted that these embodiments are merely described in detail to facilitate understanding of the present invention. Therefore, the present invention is not limited to those having all of the configurations described in the embodiments. The present invention is not limited to the above-described embodiments, and various embodiments are also included.

[0082] Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add, delete, or replace part of the configuration of each embodiment with other configurations. For example, in the embodiment, the battery cell 10 is a secondary battery, but the present invention is not limited to this, and the battery cell 10 may be a battery other than a secondary battery.

[0083] It is also possible to add the configuration of one embodiment to the configuration of another embodiment. For example, both the protruding lower end (third leg portion) 70b of the side plate (side member) 70 shown in Fig. 6 and the leg portion 30d of the plate (end member) 30 shown in Fig. 7 may be provided. In this case, both may be configured in a positional relationship in which they protrude downward from the lower surface 40a.

[0084] The battery pack 100 according to the embodiment of the present invention can be summarized as follows. [1] The battery pack 100 is a power supply device formed by fastening a plurality of stacked batteries (battery cells) 10 with a holding member, and is mounted on an object (not shown) such as an automobile.

[0085] Each of the multiple batteries (battery cells) 10 is formed by housing a power storage element (not shown) in a battery can (battery container) 11 having a bottom surface 10b, and is arranged so that the bottom surface 10b faces the side on which it is placed. At least the bottom surface 10b of the lower part of each of the multiple batteries 10 is covered with an insulating member. The power storage element is configured to store electricity, and includes a pair of positive and negative electrodes connected to terminals for inputting and outputting power, and an electrolyte filled between the electrodes.

[0086] 1, the battery pack 100 is generally a rectangular parallelepiped, i.e., a hexahedron, and will be described as having flat surfaces on its exterior in the front-to-back, left-to-right, and top-to-bottom directions. The battery pack 100 has a holding member that holds multiple batteries (battery cells) 10 stacked in the front-to-back direction.

[0087] The holding members include end members (plates) 30 and side members (side plates) 70. The end members 30 are arranged at both ends in the front-to-rear direction (stacking direction) of the stacked flat batteries (battery cells) 10. The side members 70 close and surround the left and right sides of the end members 30. The end members 30 surround the multiple batteries (battery cells) 10 and secure them together.

[0088] The bottom surface 10b of the battery (battery cell) 10 is coated with an insulating material to form an insulating layer 40. The insulating layer 40 is preferably, for example, an electrically insulating film or coating, or a rubber film. The bottom surface 10b is disposed facing the side of the battery pack 100 on which it is to be placed.

[0089] As shown in FIGS. 2 and 5A, the end member 30 has a first region A, which forms the majority of the area, on the side facing the mounting object, and a second region B, which has a smaller area. The first region A is the majority of the area of ​​the end member 30 where there are no legs. The second region B is the region B where the first leg portions 30a are formed, protruding from the bottom surface 10b toward the mounting object, i.e., the region where the legs become bases. The battery pack 100 shown in FIGS. 1 and 2 has a four-legged configuration. The battery pack 100A shown in FIGS. 4 and 5A has a six-legged configuration.

[0090] The first leg 30a protrudes slightly toward the mounting object side beyond the insulating layer 40 formed by covering the bottom surface 10b with a film or the like, thereby raising the bottom surface 10b above the mounting object side. As a result, the battery packs 100, 100A can prevent film tearing during the manufacturing process, while also improving cooling efficiency due to the raised gap.

[0091] [2] As shown in Figures 2 and 5A, in the battery pack 100, 100A of [1] above, the end member 30 has a second region B formed on both sides of the first region A, i.e., around the bottom surface 10b. This second region B forms a first leg portion 30a that protrudes from the bottom surface 10b toward the object to be placed on. In other words, the end member 30 has a bifurcated leg structure. Therefore, a gap that allows ventilation is secured in the first leg portion 30a formed around the bottom surface 10b, and the placed state can be stabilized.

[0092] In the battery pack 100A, the leg portion 30Ma of the intermediate plate 30M protrudes downward from the lower surface 40a of the insulating layer 40, similar to the leg portion 30a of the plate 30. Therefore, the battery pack 100A shown in FIG. 4 can also achieve the same effects as the battery pack 100 shown in FIG.

[0093] [3] As shown in Figures 4 and 5A, in the battery pack 100A described in [1] above, it is preferable to place a spacer (intermediate plate) 30M between the stacked batteries 10. As shown in Figure 5A, this spacer 30M preferably has a third region C on the side of the mounting object, and a fourth region D in which a second leg portion 30Ma is formed that protrudes further toward the mounting object than the third region C and the bottom surface 10b. In the battery pack 100A configured in this way, legs are also provided on the intermediate spacer 30M. As a result, the battery pack 100A can be mounted more stably by increasing the number of legs from, for example, four to six.

[0094] [4] As shown in Fig. 5A, in the battery pack 100A described in [3] above, it is preferable that the spacer (intermediate plate) 30M has a fourth region D arranged on both sides of the third region C. In the battery pack 100A configured in this manner, the middle spacer (intermediate plate) 30M is also provided with bifurcated legs. As a result, the number of bifurcated legs of the battery pack 100A is increased from four to, for example, six, allowing it to be placed more stably.

[0095] 5B shows a front view portion 500 of the end member 30 as viewed from the stacking direction Dt, and a right side view portion 510 as viewed from the width direction of the end member 30. As shown in the right side view portion 510, the edge of the end member 30 on the side of the placing surface is notched in a rounded or tapered shape, and continues from the front side to the base of the leg portion 30a.

[0096] 5A and 5B, in the stacking direction Dt of the battery 10, the width 13T of the surface of the third region C of the spacer 30M facing the mounting target is larger than the width 12T of the surface of the first region A of the end member 30 facing the mounting target. In other words, the area of ​​the surface of the third region C of the spacer 30M facing the mounting target (the area of ​​the region defined by 13T) is larger than the area of ​​the surface of the first region A facing the mounting target (the area of ​​the region defined by 12T).

[0097] The advantages of this configuration are as follows: In a battery pack in which batteries are stacked, the center tends to become hot, but the temperature of the battery module is made uniform. The center portion of the stacked battery is heat dissipated effectively. The batteries on the end member 30 side are prevented from being cooled too much. It is preferable to provide the thermally conductive member (thermally conductive sheet) 50 so that it faces, and preferably contacts, the bottom surface 10b of the battery, the surface of the spacer 30M facing the mounting object (area C), and the surface of the end member 30 facing the mounting object (area A).

[0098] The width (13T) of the surface of the third region C facing the mounting object is preferably at least twice the width (12T). This allows sufficient heat dissipation to be achieved in the central portion of the stacked batteries. Also, for example, to reduce the size of the battery module 90, the width (13T) may be no more than 10 times the width (12T). The maximum width (13T) of the spacer 30M is preferably smaller than the maximum width (11T) of the end member 30. This allows for a more compact module.

[0099] The surface of the first region A facing the mounting target (surface defined by 12T) is preferably less than half the maximum length (length defined by 11T) of the end member 30 from the side where the batteries are located in the battery stacking direction Dt. The surface of the first region A facing the mounting target (surface defined by 12T) is made sufficiently smaller than the length (length defined by 11T) of the end member 30, and is arranged on the side where the batteries 10 are located in the battery stacking direction Dt. This limits heat transfer from the underside of the end member 30, preventing excessive cooling of the batteries at the end of the stacked batteries (batteries adjacent to the end member 30). This is preferable for uniform temperature distribution of the batteries that make up the battery pack.

[0100] The surface of the first region A on the side of the mounting object (surface defined by 12T) is preferably greater than 1 / 50 of the maximum length (length defined by 11T) of the end member 30 from the side where the battery is located in the battery stacking direction Dt. This is to achieve desired heat transfer from the lower surface side of the end member 30.

[0101] Furthermore, the end member 30 preferably has a facing region 600 facing the adjacent battery 10. In this case, in the second region B, the surface facing the battery 10 has part of the facing region 600 in a part thereof.

[0102] The end member 30 presses the stacked batteries 10. In the second region B, a portion of the surface facing the battery also constitutes the facing region 600. In this case, the mounting side surface 370 of the first region A is located higher than the bottom surface of the mounting side 380 of the battery 10. Therefore, the end member 30 does not face the entire area of ​​the battery 10 it faces. The end member 30 faces the battery 10 by a portion of the second region B and an area above the second region B. The end member 30 also has an area that does not face the battery 10 (an area below the first region A (on the mounting surface side)). Therefore, the area of ​​the end member 30 facing the battery 10 can be made smaller, and the end member 30 can be made smaller.

[0103] The end of the second region B closest to the mounting surface (the wire end surface of the leg portion 30a) contacts the mounting surface, thereby stably fixing the battery pack to the mounting surface. Alternatively, if the end of the second region B closest to the mounting surface is spaced apart from the mounting surface, the contact area with the mounting surface is reduced, making it easier to control the temperature distribution. For example, it is preferable to place a cooling member between the bottom surface of the battery and the mounting surface, as this makes it easier to control the temperature distribution in the stacking direction.

[0104] [5] As shown in Fig. 3, in the battery pack 100 of the above [1], the battery (battery cell) 10 has a storage element having a positive electrode active material and a negative electrode active material, and a battery case 11 that houses the storage element. In the width direction Dw of the battery 10, which is perpendicular to the stacking direction Dt of the battery 10, the storage element 610 of any of the battery cases 11 is preferably located in a first region A, and a region of any of the battery cases 11 that does not have the storage element 610 is preferably located in a second region B, as shown in Fig. 5B.

[0105] There are no legs 30a in the first region A, and no second legs 30Ma in the third region C, ensuring a gap between the battery bottom surface 10b and the surface of the mounting portion. If the heat-generating power storage elements are positioned in the first region A and the third region C, the battery pack 100 can be cooled efficiently by ventilating the gap directly below them or by placing a thermally conductive sheet 50 nearby. Conversely, in the second region B and the fourth region D, there is a high possibility that current collecting members that do not generate heat are present instead of the power storage elements to be cooled, and therefore cooling efficiency can be improved by preventing unnecessary cooling.

[0106] [6] In the battery pack 100 described in [1] above, it is even more preferable if the first legs 30a are detachable, either as a single unit or as separate units. A battery pack 100 configured in this manner is advantageous because it offers greater flexibility in design and manufacturing processes, increasing manufacturing options. The flexibility in the manufacturing process refers to a structure that allows for convenient removal of the first legs 30a after assembling the battery pack 100 without damaging the insulating film covering the battery bottom 10b and then removing the first legs 30a after their role of protecting the insulating film has ended.

[0107] Here, the multiple first leg portions 30a, which can be attached and detached as a single unit or separately, are considered to be temporary assembly jigs. In this case, a temporary assembly jig that supports assembly in a certain manufacturing process is removed in the next process. The temporary assembly jig is temporarily fixed using screws engraved for temporary assembly, and an adhesive with adjusted adhesive strength for temporary fixation can also be used.

[0108] [7] In the battery pack 100 described in [1] above, the first leg portion 30a may have a tapered shape that narrows downward toward the mounting object. With such a configuration, the battery pack 100 can be adapted to a suitable mounting object, allowing for effective use of space.

[0109] [8] The battery pack 100 of [1] above may preferably have a tapered shape that widens downward. The battery pack 100 having such a configuration that it is difficult to tip over is more likely to maintain stability after being placed.

[0110] [9] In the battery pack 100 of any one of [1] to [8] above, a plane including the first region A within the overall bottom surface formed by connecting the bottom surfaces 10b of the multiple batteries 10 is defined as a first imaginary plane. The space between the first imaginary plane and the mounting object is defined as a first imaginary space. It is preferable to dispose both or either one of a heat conduction unit (heat conduction sheet) 50 and a heat exchange unit (cooling unit) 60 in the first imaginary space. From the viewpoint of efficient cooling, the battery pack 100 configured in this manner can effectively utilize the space between the overall bottom surface and the mounting object, i.e., the first imaginary space.

[0111]

[10] In the battery pack 100 described in [9] above, it is preferable to configure the cooling heat transfer parts arranged in the first virtual space, i.e., both the heat conduction part (heat conduction sheet) 50 and the heat exchange part (cooling part) 60, so as not to abut against the first leg part 30a and the second leg part 30Ma.

[0112] Conversely, when the legs 30a, 30Ma are contacted with a cooling heat transfer part, the legs 30a, 30Ma are cooled in the order of the end member (plate) 30, and the end cell holder 20E, and the nearest end battery cell 10E is overcooled. As a result, the temperature of the end battery cell 10E and the other batteries 10 become uneven. Therefore, to avoid such a problem, the battery pack 100 is configured so that heat transfer parts and refrigerant do not come close to the inner thighs of the legs 30a, 30Ma, thereby ensuring uniform cooling and temperature balance between the batteries.

[0113]

[11] The battery pack 100B shown in Fig. 6 differs from that described in [1] above in that it has a third leg 70b. That is, the battery pack 100C shown in Fig. 6 has a third leg 70b instead of the first leg 30a of the battery pack 100 according to Fig. 1 and the second leg 30Ma of the battery pack 100A shown in Figs. 4 and 5A.

[0114] The battery pack 100C also has end members (plates) 30 and side members (side plates) 70 as holding members that surround and fasten together the multiple batteries 10 described in [1] above. The end members 30 are arranged at both ends of the batteries (battery cells) 10 in the stacking direction. The side members 70 are connected to holding members that can surround the left and right sides of the end members 30 in a continuous frame.

[0115] 7, the side member (side plate) 70 has a third leg 70b that protrudes from the bottom surface 10b (FIG. 3) toward the mounting object side. The battery pack 100C having this configuration can be effectively used by providing the third leg 70b, shown only in FIG. 6, on the side member 70 without any additional parts or additional processing.

[0116] In the above-described embodiment, the presence of multiple leg portions 30a as a configuration relating to the second region B has been described, but this may also be a single configuration. For example, the first region A may be provided on both sides of the second region B. In this case, the connecting members 50 to the cooling member 60, etc. facing the battery, can be arranged at both ends. Alternatively, the first region A may be provided on one side and the second region B on the other side. In this case, the connecting members to the cooling member, etc. facing the battery can be arranged together on one side. In contrast, the configuration of Figure 1, in which the second region B is provided on both sides of the first region A, provides greater stability. [Explanation of symbols]

[0117] 10 battery cell (battery), 10b bottom surface (of battery cell 10), 10n narrow side (side) (of battery cell 10), 10t top surface (of battery cell 10), 10w wide side (side) (of battery cell 10), 10E end battery cell, 11 battery can, 12 battery lid, 13 (pair of) external terminals, 14 gasket, 15 gas release valve, 16 filling hole, 17 filling plug, 20 cell holder (generic term), 20E end cell holder, 20M intermediate cell holder, 23 (attached to end cell holder 20E) fixing part, 23a nut, 30 plate (end member), 30a (first) leg, 30M intermediate plate (spacer), 30Ma second leg, 33 through hole, 40 insulating layer, 40a bottom surface (of insulating layer 40), 50 Heat conduction sheet (heat conduction section), 60 cooling section (heat exchange section), 61 screw holes, 70 side plate (side member), 70b third leg section, 90, 90A battery module, 91 input / output terminal, 91E end bus bar, 92 volts, 100, 100A to 100C assembled battery, 101 input / output cable, 120 center space, Dh height direction (of battery cell 10), Dt thickness direction (of battery cell 10), Dw width direction (of battery cell 10)

Claims

1. A battery pack is mounted on a mounting object by fastening a plurality of stacked batteries with a holding member, Each of the plurality of batteries a battery container having a bottom surface and housing an electricity storage element; At least the bottom surface is covered with an insulating member, The bottom surface is disposed facing the target side, the holding member has end members disposed at both ends of the battery in the stacking direction, The end member is provided on the mounting target side. A first region; a second region formed to protrude toward the placement target side from the first region and the bottom surface; and the surface of the first region facing the mounting target is provided in a range of ½ or less of the maximum length of the end member from the side where the battery is located in the stacking direction of the plurality of batteries; Battery pack.

2. A battery pack as described in claim 1, wherein the multiple legs that respectively form the second regions are detachable either as a single unit or separately.

3. The leg portion has a tapered shape that narrows downward toward the object to be placed on. The battery pack according to claim 2 .

4. The leg portion has a tapered shape that widens downward toward the object to be placed on. The battery pack according to claim 2 .

5. a heat conduction unit and / or a heat exchange unit are disposed in a first virtual space between a first virtual plane that is a bottom surface of the plurality of batteries and includes the first region, and the placement target; The battery pack according to claim 2 .

6. and both the heat conducting portion and the heat exchanging portion disposed in the first virtual space are not in contact with at least the leg portion. The battery pack according to claim 5 .

7. The second region is disposed on both sides of the first region. The battery pack according to claim 1 or 2.

8. a spacer disposed between the plurality of stacked batteries; the spacer has a third region on the side of the mounting target, and a fourth region protruding from the third region and the bottom surface toward the side of the mounting target. The battery pack according to claim 1 or 2.

9. the spacer has the fourth region disposed on both sides of the third region; The battery pack according to claim 8 .

10. The battery includes a storage element having a positive electrode active material and a negative electrode active material, and a battery container that houses the storage element; In a width direction of the battery perpendicular to a stacking direction of the batteries, the storage element of any of the battery containers is located in the first region, and a region of any of the battery containers not having the storage element is located in the second region. The battery pack according to claim 1 or 2.

11. a width of a surface of the third region of the spacer facing the mounting target is greater than a width of a surface of the first region of the end member facing the mounting target in a stacking direction of the plurality of batteries; The battery pack according to claim 8 .

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