ENERGY STORAGE DEVICE AND VEHICLE

Abstract

Energy storage device (4; 150) with: at least one energy storage module (30, 31, 32, 33, 34, 35, 36, 37, 38, 39; 155, 156, 157, 158, 159, 160, 161, 162, 163) arranged between a first frame (22; 109; 176) and a second frame (20, 21; 101, 102; 178), which are arranged at a distance from one another, wherein the energy storage module (30, 31, 32, 33, 34, 35, 36, 37, 38, 39; 155, 156, 157, 158, 159, 160, 161, 162, 163) has a plurality of energy storage cells (42, 62; 165) arranged in sequence, wherein the first frame (22; 109; 176) and the second frame (20, 21; 101, 102; 178) are provided in a vehicle (1) or the energy storage device (4; 150); and a fastening device (43, 44, 45, 46, 63, 64, 65, 66; 181, 182), wherein: the energy storage module (30, 31, 32, 33, 34, 35, 36, 37, 38, 39; 155, 156, 157, 158, 159, 160, 161, 162, 163) is fixed to the first frame (22; 109; 176) by the fastening device (43, 44, 45, 46, 63, 64, 65, 66; 181, 182) and is not fixed to the second frame (20, 21; 101, 102; 178); a plurality of energy storage modules (30, 31, 32, 33, 34, 35, 36, 37, 38, 39) are provided in the energy storage device (4); the energy storage modules (30, 31, 32, 33, 34, 35, 36, 37, 38, 39) comprise a first energy storage module (30) and a second energy storage module (31); the energy storage modules (30, 31, 32, 33, 34, 35, 36, 37, 38, 39) further have a busbar (53) that electrically connects the first energy storage module (30) and the second energy storage module (31) to each other; and the bus bar (53) is configured to connect a terminal of the first energy storage module (30) and a terminal of the second energy storage module (31) to each other, wherein the terminal of the first energy storage module (30) is a terminal on one end side of the first energy storage module (30) and is located on the side of the first frame, and wherein the terminal of the second energy storage module (31) is a terminal on one end side of the second energy storage module (31) and is located on the side of the first frame.

Description

BACKGROUND OF THE INVENTION1. Field of the InventionThe present invention relates to an energy storage device and a vehicle.2. DESCRIPTION OF THE RELATED ARTThere are various proposals for an energy storage device including an energy storage module. For example, Japanese Unexamined Patent Application Laid-Open No. 2016-122272 discloses an energy storage device disposed between a first side member and a second side member of a vehicle.The first side member and the second side member are disposed at a distance from each other in the vehicle width direction. The energy storage device has an energy storage module, a first mounting element and a second mounting element. The energy storage module has a plurality of energy storage cells arranged in the vehicle width direction. An end portion of the energy storage module on the first side member side is fixed to the first side member by the first mounting member. An end portion of the energy storage module on the second side member side is fixed to the second side member by the second mounting member.WO 2017 / 068876 A1 discloses a battery pack in which battery modules, each of which is constructed from a plurality of battery cells, are accommodated in a housing. The battery pack is provided with: a cylindrical box-like component having an opening; a cover component for covering the opening of the box-like component; and a sub-assembly which is a component in which each of the battery modules is fixed to at least one main surface of each of the base plates, the sub-assembly being accommodated in a housing formed by the box-like component and the cover component and fixed to the box-like component. Each of the base plates has screw holes in each of which helical thread grooves are formed in the opening direction of the box-shaped member, and the cover member is fixed to the base plates by screwing with screws.DE 11 2015 001 140 T5 discloses a battery pack. The battery pack includes a housing having an inner surface and a battery module accommodated in the housing. The battery module has a battery unit and two end plates. The battery unit has battery cells arranged side by side. The end plates hold the battery unit between them. At least one of the end plates has a protrusion that protrudes further toward the inner surface of the housing than the battery unitDE 11 2008 000 148 T5 discloses a battery pack comprising: a battery having a plurality of stacked battery cells, a battery housing accommodating the battery, and a retaining band generating a fastening force in the stacking direction of the battery cells in order to hold the plurality of battery cells together. The tightening strap is fastened to the battery housing. This structure provides the battery pack that fixes the battery to the case body while suppressing the increase in the number of parts.US 2016 / 0190526 A1 discloses a power storage module. The power storage module includes a storage cell group, first and second end plates, a first tether, a second tether, and at least one intermediate plate. The first tether is provided to face a first side surface of the memory cell group and is connected to the first and second end plates to retain the memory cell group. The first tether includes a first flat surface, a first bent portion, and a second bent portion. The second tether includes a second flat surface, a third bent portion, and a fourth bent portion. The at least one intermediate plate is disposed at an inner position in the memory cell group in a stacking direction. The first and third bent portions or portions near the first and third bent portions are connected to the at least one intermediate plate.SUMMARY OF THE INVENTIONIt is often the case that gas is accumulated inside the energy storage cells due to deterioration with time. When the energy storage cells deform to expand (expansion), the energy storage module is deformed to expand in the vehicle width direction.When the energy storage module is deformed to expand in the vehicle width direction, high loads are applied to the first mounting member and the second mounting member so that the first mounting member and the second mounting member are deformed.It is the object of the present invention to provide an energy storage device and a vehicle which can restrain the occurrence of various adverse effects that otherwise occur due to the energy storage cells deforming to expand.This object is achieved by an energy storage device having the features of claim 1. An alternative energy storage device is set out in claim 4. Advantageous further developments are the subject of the dependent claims. A vehicle having an energy storage module is set out in claim 8.According to claim 1, the energy storage module is fixed to the first frame, but the energy storage module is not fixed to the second frame. Therefore, the deformation of the energy storage module is allowed, and the deformation of the first frame and the second frame can be restrained. As a result, it is possible to restrain occurrence of various adverse effects that may occur due to deformation of the energy storage module. In the aspect explained above, the energy storage module may be pressed against the second frame and may be in contact with the second frame.According to the above-described energy storage device, the energy storage module is fixed to the first frame and is pressed against the second frame and is in contact with the second frame. Therefore, the energy storage module is prevented from being deformed to expand in the arrangement direction of the first frame and the second frame. As a result, it is possible to restrain the occurrence of various adverse effects that may otherwise occur due to the energy storage module deforming to expand.In the above-described aspect, the energy storage module may be pressed against the second frame upon expansion of the energy storage module, and is in contact with the second frame.According to claim 4, the energy storage module is fixed to the first portion on the side of the first frame, and no fixing is provided to the second portion on the side of the second frame. Therefore, when the energy storage cells deform to expand, the energy storage module is allowed to deform to expand to the second frame side.In this case, since no fixation is provided on the side of the second portion, even if the energy storage module deforms to expand toward the side of the second frame, occurrence of adverse effects occurring in the energy storage device of the related art is prevented.In the above aspect, the second portion may be pressed against the second frame and is in contact with the second frame.The above-described energy storage device is pressed against and in contact with the second frame on the second portion side, and is fixed to the first frame by the fixation so as to prevent the energy storage module from deforming to expand. Therefore, it is possible to restrain the occurrence of various adverse effects that may otherwise occur because the energy storage module deforms to expand.In the above-described aspect, the energy storage cells may be arranged in a sequence (sequentially) in a facing direction in which the first frame and the second frame face each other; wherein the energy storage module may include a holder that holds the energy storage cells; wherein the holder may hold the energy storage cells such that the energy storage cells are arranged in sequence in the facing direction; and wherein the holder may be configured to be deformed in the facing direction.In the above-described energy storage device, when a load that causes the energy storage module to expand in the arrangement direction is applied to the holder due to the energy storage cells deforming to expand, the holder may be deformed to extend in the arrangement direction.In claims 1 and 4, a plurality of energy storage modules are provided in the energy storage device; wherein the energy storage modules may include a first energy storage module and a second energy storage module; wherein the energy storage modules further have a bus bar (busbar) that electrically connects the first energy storage module and the second energy storage module to each other; and wherein the bus bar may be configured to connect a terminal of the first energy storage module and a terminal of the second energy storage module to each other; wherein the terminal of the first energy storage module is a terminal on an end side of the first energy storage module that is on the side of the first frame, and the terminal of the second energy storage module is a terminal on an end side of the second energy storage module that is on the side of the first frame.In the above-described energy storage device, even when the first energy storage module or the second energy storage module is deformed to extend (expand) in the arrangement direction, since the end portions of the first energy storage module and the second energy storage module on the first frame side are fixed to the first frame, the positions of these end portions are prevented from being displaced.As a result, it is possible to avoid offsetting the positions of both ends of the bus bar and thus to restrain damage to the end portions of the bus bar.In the aspect explained above, the energy storage cells may be arranged in sequence in the arrangement direction perpendicular to a direction in which the first frame and the second frame face each other.In claim 8, the energy storage module may be pressed against the second frame upon expansion of the energy storage module and is in contact with the second frame.According to the energy storage device and the vehicle of the present invention, it is possible to restrain occurrence of various adverse effects that may otherwise occur because the energy storage cells deform to expand.BRIEF DESCRIPTION OF THE DRAWINGSThe features, advantages, and technical and industrial significance of the embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals denote like elements. FIG. 1 shows a schematic illustration of a vehicle 1. FIG. 2 shows a schematic perspective illustration of an energy storage device 4. FIG. 3 is a schematic plan view of the energy storage device 4 in a state in which a lid 11 is removed. FIG. 4 shows a perspective view of a portion of the energy storage device 4. FIG. 5 shows a plan view of a portion of the energy storage device 4. FIG. 6 is a sectional view taken along a line VI-VI of FIG. 5. FIG. 7 is a sectional view of an energy storage cell 42 shown in FIG. 4 etc. FIG. 8 is a flowchart of a manufacturing process, showing the processes for forming the energy storage device 4. FIG. 9 is a plan view showing a state in which the energy storage module 30 has deteriorated with the lapse of time. FIG. 10 shows a plan view of the energy storage device 4. FIG. 11 is a plan view showing a portion of a skeleton frame 100 provided on a vehicle body 2. FIG. 12 is a plan view showing a state in which energy storage modules 30 to 39 have deteriorated with the lapse of time. FIG. 13 shows a schematic perspective view of an energy storage device 150. FIG. 14 is a schematic perspective view of an energy storage unit 152. FIG. 15 is a plan view of a case body 153. FIG. 16 shows a perspective view of an energy storage module 160 and the structure around the energy storage module 160. FIG. 17 shows a side view of the energy storage module 160 and the structure around the energy storage device 160. FIG. 18 shows a sectional view of an energy storage cell 165. FIG. 19 is a schematic sectional view showing a state in which a holding plate 184 of the energy storage module 160 is pressed against and in contact with a cross frame 178.DETAILED DESCRIPTION OF THE EMBODIMENTSReferring to Figs. 1 to 19, first to third embodiments will be described. The same reference numerals are assigned to the same or substantially the same configurations in FIGS. 1 to 19, and repeated description thereof is omitted.First EmbodimentFIG. 1 is a schematic diagram of a vehicle 1. the vehicle 1 includes a vehicle body 2, a driving device 3, an energy storage device 4, front wheels 5, and rear wheels 6. the front wheels 5 are provided on the front side of the vehicle 1 with respect to the center of the vehicle 1 in the vehicle front-rear direction D, and the rear wheels 6 are provided on the rear side of the vehicle 1 with respect to the center of the vehicle 1 in the vehicle front-rear direction D.The vehicle body 2 is formed with an boarding space, a front sub-skin space, and a rear sub-skin space. The boarding space is a space in which an occupant such as a driver gets on and takes place. The rear accommodation space is formed behind the boarding space. Luggage, etc. is placed in the rear accommodation space. The front accommodation space is formed in front of the boarding space. The driving device 3 etc. are disposed in the front accommodation space.The vehicle body 2 has a skeleton frame. The skeleton frame has a bottom panel 9. The floor panel 9 forms the floor of the vehicle body 2.The drive device 3 includes a rotary electric machine 7 and a power control unit (PCU) 8. The PCU 8 includes an inverter and a converter. The rotary electric machine 7 is mechanically connected to the front wheels 5.The energy storage device 4 is provided on a lower surface of the floor panel 9. The energy storage device 4 supplies DC energy to the PCU 8. The PCU 8 boosts the voltage of the supplied DC energy and then converts the boosted DC energy into AC energy. Using the AC power supplied from the PCU 8, the rotary electric machine 7 generates a driving force that rotates the front wheels 5.The vehicle 1 may be an electric vehicle or may be a plug-in hybrid vehicle or a hybrid vehicle.FIG. 2 is a schematic perspective view of the energy storage device 4. the energy storage device 4 includes a battery case 10. the battery case 10 includes a case body 12 and a lid 11. the case body 12 is formed with an opening that is open upward. The case body 12 is made of, for example, a metal material such as an aluminum alloy. The case body 12 is fixed to the bottom panel 9. The lid 11 is provided on the case body 12 so as to close the opening of the case body 12. The cover 11 is made of, for example, plastic to save the weight of the battery case 10.FIG. 3 is a schematic plan view of the energy storage device 4 in a state in which the lid 11 is removed. Here, FIG. 3 shows the energy storage device 4 in a state before the occurrence of the deterioration with the lapse of time.The power storage device 4 includes the case body 12, a reinforcement member 15, an assembled device 16, and a power storage unit 17. the case body 12 is formed hollow and has a bottom plate and a peripheral wall portion extending along the outer periphery of the bottom plate. The case body 12 has a body portion 13 and a protruding portion 14. the body portion 13 is formed in a generally rectangular parallelepiped shape. The protruding portion 14 is formed to protrude forward from a front end portion of the body portion 13. The protruding portion 14 is formed such that its length in the width direction W of the vehicle body 2 decreases as viewed forward from its connection portion to the body portion 13.The assembled device 16 is provided in the protruding portion 14. The assembled device 16 includes a cooling device 18 and a connection box 19. the cooling device 18 is a device for cooling the power storage unit 17.The reinforcing member 15 is disposed in the body portion 13. The reinforcing member 15 has a bottom plate 29 and a plurality of frames arranged in a lattice pattern. In FIG. 3, the bottom plate 29 of the reinforcing member 15 is disposed on an upper surface of the bottom plate of the case body 12.The reinforcing member 15 has side frames 20 and 21, a center frame 22, and cross frames 23 to 28.The side frames 20 and 21 and the center frame 22 are formed to extend in the front-rear direction D. The side frames 20 and 21 are disposed at a distance from each other in the width direction W, and the center frame 22 is disposed between the side frames 20 and 21.The cross frames 23 to 28 are formed to extend in the width direction W such that each of the cross frames 23 to 28 connects the side frame 20 and the side frame 21 to each other. The cross frames 23 to 28 are spaced apart from each other in the front-rear direction D.In this manner, the frames are arranged in a grid pattern such that accommodation spaces in which energy storage modules 30 to 39 are respectively arranged are formed by the frames and the bottom plate 29.FIG. 4 is a perspective view of a part (portion) of the energy storage device 4, and FIG. 5 is a plan view of the portion of the energy storage device 4. the energy storage module 30 is disposed in the accommodation space formed by the cross frames 23, 24, the side frames 21, and the center frame 22. Similarly, the energy storage module 31 is disposed in the accommodation space formed by the side frame 21, the center frame 22, and the cross frames 24 and 25.The energy storage module 30 includes a cell row 40, a cell row 41, and a holder (retainer) 47. the energy storage module 30 is provided with fasteners 43 to 46 and a plurality of bus bars 52, 53, 54, 55, 56. The cell row 40 and the cell row 41 are arranged in the front-rear direction D. The cell row 40 has a plurality of energy storage cells 42 arranged in the width direction W, and the cell row 41 also has a plurality of energy storage cells 42 arranged in the width direction W. Insulation plates are respectively arranged between the energy storage cells 42.The holder 47 has end plates 48, 49 and bands 50, 51. the end plate 48 is provided on end sides of the cell rows 40, 41 on the front end side in the width direction W. The end plate 49 is provided on end sides (end surfaces) of the cell rows 40, 41 on the second end side in the width direction W. The end plates 48, 49 are each formed of, for example, a metal plate member and an insulating member covering the surface of the plate member.The band 50 and the band 51 are made of, for example, a plastic material. Therefore, when loads are applied to the end plate 48 and the end plate 49 in the directions in which they are pushed away from each other, the band 50 and the band 51 are deformed to expand. In this manner, the tape 50 and the tape 51 are formed stretchable (extensible) in the width direction W. By the holder 47 thus constructed, the energy storage cells 42 of the cell rows 40, 41 are held so as to be arranged in the width direction W.The energy storage module 30 has an end portion 57 disposed at a first end in the width direction W and an end portion 58 disposed at a second end in the width direction W, and the fasteners 43, 44, 45, 46 fix the end portion 57 to the center frame 22. The end portion 57 is in close contact with the center frame 22.In the example shown in FIG. 5 etc., the end portion 57 of the energy storage module 30 is fixed to the center frame (first frame) 22, but the fixing position is not limited to the above-described position.For example, a portion of the energy storage module 30 on the side of the center frame 22 with respect to the center of the energy storage module 30 in the width direction W may be fixed to the center frame 22.That is, in the present invention, the portion of the energy storage module 30 on the center frame 22 side (first frame) 22 means a portion of the energy storage module 30 located on the center frame 22 side with respect to the center of the energy storage module 30 in the width direction W (arrangement direction).With respect to the portion of the energy storage module 30 located on the side of the center frame 22 and a portion of the energy storage module 30 located on the side of the side frame 21, the fasteners 43 to 46 that fix the energy storage module 30 to the reinforcing member 15 are provided only on the portion of the energy storage module 30 located on the side of the center frame 22.The energy storage module 30 is provided with the bus bars 52, 53, 54, 55, 56. The bus bars 54 are provided on the cell row 40. The bus bars 54 connect in series the energy storage cells 42 that are adjacent to each other in the width direction W.The bus bar 55 connects the cell row 40 and the cell row 41 in series. More specifically, the bus bar 55 connects in series the energy storage cell 42 of the cell row 40 located on the side frame 21 side and the energy storage cell 42 of the cell row 41 located on the side frame 21 side.The bus bars 56 are provided on the cell row 41. The bus bars 56 connect in series the energy storage cells 42 that are adjacent to each other in the width direction W.The bus bar 53 connects the energy storage module 30 and the energy storage module 31 in series. More specifically, the bus bar 53 is connected to the power storage cell 42 of the cell row 41 that is closest to the center frame 22.FIG. 6 is a sectional view taken along line VI-VI of FIG. 5 ; the energy storage module 30 includes a bolt (bolt) 59 that fixes the end plate 48 to the bottom plate 29 of the reinforcing member 15 and to the bottom plate of the case body 12.Referring back to FIG. 5, the end plate 49 (the end portion 58) of the energy storage module 30 is not fixed. Therefore, the end portion 58 is provided to be movable in the width direction W when the cell rows 40, 41 extend in the width direction W. The energy storage module 30 is disposed on an upper surface of the bottom plate 29, and the end plate 49, which is the end portion 58, is movable in the width direction W on the upper surface of the bottom plate 29.The energy storage module 31 is constructed like the energy storage module 30. The energy storage module 31 has cell rows 60, 61 and a holder 67.The cell rows 60, 61 each have a plurality of energy storage cells 62 arranged in the width direction W. In the cell row 60, the energy storage cells 62 are connected in series by bus bars. In addition, in the cell row 61, the energy storage cells 62 are connected in series by bus bars.The cell row 60 and the cell row 61 are connected in series by a bus bar. The energy storage module 31 is connected in series to the energy storage module 30 through the bus bar 53. More specifically, the bus bar 53 connects in series the energy storage cell 62 of the cell row 60 located at an end of the cell row 60 on the side of the center frame 22 and the energy storage cell 42 of the cell row 41 located at an end of the cell row 41 on the side of the center frame 22.The holder 67 includes end plates 68, 69 and bands 70, 71. the end plate 68 is provided at ends of the cell rows 60, 61 on the side of the center frame 22. The end plate 69 is provided at ends of the cell rows 60, 61 on the side of the side frame 21. The bands 70, 71 are provided to connect the end plate 68 and the end plate 69 to each other. The belts 70, 71 are also made of a plastic material or the like and thus formed to be stretchable (stretchable) in the width direction W.The energy storage module 31 has an end portion 72 located at one end in the width direction W and an end portion 73 located at the side opposite to the end portion 72. The fasteners 63, 64, 65, 66 fix the end portion 72 of the energy storage module 31 to the center frame 22, more specifically, the end plate 68 is located at the end portion 72, and the fasteners 63 to 66 fix the end plate 68 to the center frame 22.The end plate 68 is fixed to the bottom plate of the case body 12 and to the bottom plate 29 by a bolt (bolt) 74.On the other hand, the end portion 73 of the energy storage module 31 is not fixed and is provided to be movable in the width direction W on the upper surface of the bottom plate 29. The end plate 69 is disposed at the end portion 73.In the state shown in FIG. 5, the end plate 69 is disposed at a distance from the side frame 21.FIG. 7 is a sectional view of the energy storage cell 42 shown in FIG. 4 etc. The energy storage cell 42 includes an accommodation case 80, a positive electrode external terminal 83, a negative electrode external terminal 84, an electrode assembly 85, an electrolytic solution 88, a positive electrode current collecting terminal 89, and a negative electrode current collecting terminal 90.The accommodation case 80 includes a case body 81 and a lid 82. the case body 81 is formed with an opening that is open upward. The lid 82 is welded to the case body 81 so as to close the opening of the case body 81.The positive electrode outer terminal 83 and the negative electrode outer terminal 84 are provided on an upper surface of the lid 82. The bus bars 54 or the like are connected to the positive electrode external terminal 83 and the negative electrode external terminal 84. The electrode assembly 85, the electrolyte solution 88, the positive electrode current collecting terminal 89, and the negative electrode current collecting terminal 90 are disposed in the accommodation case 80.The electrode assembly 85 includes a plurality of negative electrode sheets, a plurality of positive electrode sheets, and a plurality of separators. The electrode assembly 85 may be either a stack-type electrode assembly or a wound-type electrode assembly (winding-type).The negative electrode sheet has a metal foil such as a copper foil and negative electrode mixture layers formed on the front surface and the back surface of the metal foil. The negative electrode mixture layer contains a negative electrode active material, a binder, etc. A carbonaceous material or the like can be applied as the negative electrode active material. The metal foil of the negative electrode sheet has an uncoated portion where no negative electrode mixture layer is formed.The positive electrode sheet has a metal foil such as aluminum foil and positive electrode mixture layers formed in the front surface and the back surface of the metal foil. The positive electrode mixture layer contains a positive electrode active material, a binder, etc. The metal foil of the positive electrode sheet has an uncoated portion where no positive electrode mixture layer is formed. The separator is formed by a microporous plastic sheet, a nonwoven fabric (nonwoven fabric), or the like.The electrode assembly 85 has positive electrode portions 86 and negative electrode portions 87. the positive electrode portions 86 are formed by the uncoated portions of the positive electrode sheets. The negative electrode portions 87 are formed by the uncoated portions of the negative electrode sheets.The positive electrode current collecting terminal 89 is provided to be connected to the positive electrode portions 86 and the positive electrode outer terminal 83. The negative electrode current collecting terminal 90 is provided to be connected to the negative electrode portions 87 and the negative electrode outer terminal 84.The electrolyte solution 88 contains, for example, at least either propylene carbonate (PC) and / or ethylene carbonate (EC). The electrolyte solution 88 contains an additive. As the additive, the electrolyte solution 88 contains at least one of vinyl acetate (VA), divinyl adipate (ADV), and / or allyl methyl carbonate (ACM).The processes for forming the energy storage device 4 configured as described above will be briefly described below. FIG. 8 is a manufacturing process flow diagram showing the processes for forming the energy storage device 4. The processes for forming the energy storage device 4 include an electrode assembly forming process S 10, a lid unit forming process S 11, an electrode assembly inserting process S 12, a welding process S 13, a casting process S 14, a sealing process S 15, a module forming process S 16, an installation process S 17, an additive decomposition process (additive degradation process) S 18, an initial charging process S 19, and an aging process S 20.The electrode assembly forming process S 10 is a process for forming the electrode assembly 85. more specifically, the electrode assembly forming process S 10 includes a process for stacking the separator, the positive electrode sheet, the separator, and the negative electrode sheet one on another.The lid unit forming process S 11 is a process of connecting the positive electrode outer terminal 83, the negative electrode outer terminal 84, the lid 82, the positive electrode current collecting terminal 89, the negative electrode current collecting terminal 90, and the electrode assembly 85 to each other. More specifically, the lid unit forming process S 11 includes a process of coupling an upper end portion of the positive electrode current collecting terminal 89 to the positive electrode outer terminal 82, and a process of coupling an upper end portion of the negative electrode current collecting terminal 90 to the negative electrode outer terminal 84.In the electrode assembly insertion process S 12, the electrode assembly 85 coupled to the lid 82 is inserted into the case body 81. Then, the lid 82 is disposed at the opening edge portion of the case body 81. In the welding process S 13, the outer peripheral edge portion of the lid 82 and the opening edge portion of the case body 81 are welded to each other. In this manner, the accommodation case 80 is formed.In the casting process S 14, the electrolyte solution 88 is supplied into the accommodation case 80 through a pouring hole formed in the lid 82. The sealing process S 15 is a process for sealing the pouring hole formed in the lid 82.In this manner, the energy storage cell 82 can be formed by the processes from the electrode assembly forming process S 10 to the sealing process S 15.The module forming process S 16 includes a cell row forming process and a holding process. The cell row forming process is a process for forming the cell row 40 and the cell row 41. the energy storage cells 42 of the cell rows 40 and 41 are connected in series by the bus bars 54, 55, 56.The holding process is a process of holding the cell row 40 and the cell row 41 using the holder 47. By the same processes, the other energy storage modules 31 to 39 are also formed.The installation process S 17 includes a module arrangement process and a module fixing process. The module arrangement process is a process for arranging the energy storage modules 30 to 39 in the energy storage module accommodation spaces formed by the frames of the reinforcing member 15.In this case, as shown in FIG. 5 etc., the length of the energy storage module 30 in the width direction W is shorter than the distance between the side frame 21 and the center frame 22 in the width direction W. Therefore, when the energy storage module 30 is disposed between the side frame 21 and the center frame 22, the energy storage module 30 can be disposed with ease. Similarly, the energy storage modules 31 to 39 can also be easily disposed in the accommodation spaces formed by the reinforcing member 15.In the module fixing process, the energy storage module 30 is fixed to the center frame 22 using the fasteners 43, 44, 45, 46 and the bolt 59. Similarly, the other energy storage modules 31 to 39 are also fixed to the center frame 22.In this case, the energy storage modules 30 to 34 are in a state where their end portions on the side of the side frame 21 are spaced apart from the side frame 21. Similarly, the energy storage modules 35 to 39 are in a state where their end portions on the side of the side frame 20 are spaced apart from the side frame 20.The additive decomposition process S 18 is a process for decomposing (decomposing) the additive of the electrolyte solution by applying a predetermined potential to each energy storage cell. More specifically, the additive decomposition process S 18 is a process of electrolysis of vinyl acetate (VA), divinyl adipate (ADV), and allyl methyl carbonate (ACM).The initial charging process S 19 is a process of forming solid electrolyte interfacial (SEI) films on the surfaces of the negative electrode mixture sheets of the negative electrode sheets, respectively. In the initial charging process S 19, the energy storage cells 42 are charged. Consequently, the SEI films are respectively formed on the surfaces of the negative electrode mixture layers of the negative electrode sheets by the electrolysed additive. By forming the SEI films on the surfaces of the negative electrode mixture layers, the surfaces of the negative electrode mixture layers can be protected from the electrolyte solution 88.The aging process S 20 is a process in which the energy storage cells 42 remain in a charged state at a predetermined temperature for a predetermined period of time (for example, 2 weeks to 3 weeks). The aging process S 20 is a process for identifying the energy storage cell 42 having a high self-discharge rate and replacing it with a normal energy storage cell 42.Here, gas is generated in the energy storage cells 42 in the additive decomposition process S 18, the initial charging process S 19, and the aging process S 20. As a result, the accommodation cases 80 of the energy storage cells 42 expand.As shown in FIG. 5 etc., the accommodating cases 50 of the energy storage cells 42 are in an expanded state at the time when the aging process S 20 has been completed.When the energy storage cells 42 expand, a load is applied to the end plate 49 in such a manner that the end plate 49 moves toward the side frame 21. Since the belts 50, 51 are made of an extensible material, the belts 50, 51 are deformed so that the length of the belts 50, 51 increases in the width direction W.Since the belts 50, 51 are deformed to expand, the energy storage module 30 can be deformed to expand in the width direction W. Since the end portion 57 of the energy storage module 30 is fixed to the center frame 22, the end portion 58 moves toward the side frame 21.In the processes such as the additive decomposition process S 18, there is a possibility that a variation occurs between the expansion rate of the energy storage cells 42 and the expansion rate of the energy storage cells 62. Therefore, there are cases where the positions of the end portion 58 of the energy storage module 30 and the end portion 73 of the energy storage module 31 are offset from each other in the width direction W.Here, it is assumed that the bus bar 53 connecting the energy storage module 30 and the energy storage module 31 is provided on the end portion 58, 73 side. In this case, when the positions of the end portion 58 of the energy storage module 30 and the end portion 73 of the energy storage module 31 are offset from each other in the width direction W, there is a possibility of damage to the bus bar 53, the external terminals of the energy storage cells 42, 62, etc.On the other hand, in this embodiment, the bus bar 53 connecting the energy storage module 30 and the energy storage module 31 is provided on the end portion 57, 72 side of the energy storage modules 30, 31. Since the end portions 57, 72 are fixed to the center frame 22, the positions of the end portions 57, 72 will not change even if the expansion states of the energy storage cells 42, 62 are different from each other. Therefore, even when the expansion states of the energy storage cells 42, 62 are different from each other, it is possible to avoid damage to the bus bar 53, etc.While the energy storage module 30 is mainly described above, the same treatments are applied to the energy storage module 31, etc.In addition, there are cases where the energy storage cells 42 of the energy storage module 30 deteriorate over time by repeated charging and discharging of the energy storage module 30. when the energy storage cells 42 deteriorate over time, the electrolyte solution 88 is decomposed, whereby oxygen, hydrogen, and hydrocarbon are generated, so that gas is accumulated in the accommodation cases 80, expanding the accommodation cases 80. As a result, the energy storage module 30 is deformed to expand in the width direction W.When the energy storage module 30 is deformed to expand in the width direction W, the end portion 58 of the energy storage module 30 is moved to approach the side frame 21.In this case, the belts 50, 51 of the holder 47 may be deformed to expand in the width direction W so that the energy storage module 30 may deform.Further, since fasteners or the like are not provided at the end portion 58 of the energy storage module 30, the fasteners or the like are prevented from being deformed due to the deformation of the energy storage module. That is, a failure due to deformation of the energy storage module 30 is prevented from occurring.FIG. 9 is a plan view showing a state in which the energy storage module 30 has deteriorated with time. As the deformation of the energy storage module 30 progresses, the end portion 58 is firmly pressed against the side frame 21.When the end portion 58 of the energy storage module 30 is firmly pressed against the side frame 21, the energy storage module 30 is fixed between the side frame 21 and the center frame 22.Therefore, even if the energy storage module 30 continues to attempt to deform so as to expand in the width direction W, the deformation of the energy storage module 30 is stopped by the side frame 21 and the center frame 22. By preventing the deformation of the energy storage module 30 in this manner, it is possible to prevent occurrence of various adverse effects that would otherwise occur due to the deformation of the energy storage module 30.While the energy storage module 30 is described above in detail, the energy storage modules 31 to 39 are also deformed like the energy storage module 30, as shown in FIG. 10. Thus, the energy storage modules 31 to 34 are fixed between the center frame 22 and the side frame 21, and the energy storage modules 35 to 39 are fixed between the center frame 22 and the side frame 20.In the first embodiment described above, the energy storage module 30 is fixed between the side frame 21 and the center frame 22 using a phenomenon that the energy storage cells 42 are deformed to expand as the energy storage cells 42 deteriorate over time. On the other hand, the energy storage module 30 may be fixed between the side frame 21 and the center frame 22 using the deformation of the energy storage module 30 in the processes from the additive decomposition process S 18 to the aging process S 20.That is, in the processes from the additive decomposition process S 18 to the aging process S 20, the energy storage module 30 is deformed to expand in the width direction W. The configuration may be such that the energy storage module 30 is firmly pressed against the side frame 21 at the time of completion of the aging process S 20.According to the energy storage device 4 of the first embodiment, the energy storage modules 30, 31 are fixed to the side frame 21 using deformation of the energy storage cells 42, 62. Therefore, when the energy storage modules 30, 31 are arranged in the reinforcing member 15, the degree of freedom of the length of the energy storage modules 30, 31 in the width direction W is high, and therefore it is possible to reduce time and effort in manufacturing the energy storage modules 30, 31.Second EmbodimentIn the first embodiment, the energy storage modules 30 to 39 are fixed to the reinforcing member 15 provided in the case body 12. However, the location of fixing the energy storage modules 30 to 39 is not limited to the reinforcing member 15. The energy storage device 4 of the second embodiment will be described below with reference to FIG. 11 etc. FIG. 11 is a plan view showing a part of a skeleton frame 100 provided on the vehicle body 2. The skeleton frame 100 has side members 101, 102, cross members 103, 104, 105, 106, 107, 108, a center member 109 and a sub-cover 110.The side members 101, 102 and the center member 109 are formed to extend in the front-rear direction D.The side members 101, 102, the cross members 103, 104, 105, 106, 107, 108, and the center member 109 are arranged in a lattice pattern such that accommodation spaces in which the energy storage modules 30 to 39 are respectively arranged are formed by these members.The undercover 110 is disposed on the lower side of the side members 101 and 102 and the cross members 103 to 108.The energy storage modules 30 to 39 are fixed to the center member 109. More specifically, the end portions of the energy storage modules 30 to 39 on the center member 109 side are fixed to the center member 109, while the end portions of the energy storage modules 30 to 39 on the opposite side are not fixed and provided to be movable in the width direction W. The energy storage modules 30 to 39 are disposed on an upper surface of the undercover 110.FIG. 11 is a plan view showing a state before the energy storage modules 30 to 39 have deteriorated with the lapse of time. Spaces are formed between the end portions of the energy storage modules 30 to 34 on the side member 101 side and the side member 101. Similarly, spaces are formed between the end portions of the energy storage modules 35 to 39 on the side member 102 side and the side member 102. FIG. 12 is a plan view showing a state in which the energy storage modules 30 to 39 have deteriorated with the lapse of time. The energy storage modules 30 to 39 are deformed to extend in the width direction W due to deterioration of the energy storage modules 30 to 39 with the lapse of time. Consequently, the end portions of the energy storage modules 30 to 34 on the side member 101 side are brought into close contact with the side member 101 so that the energy storage modules 30 to 34 are fixed between the center member 109 and the side member 101. Similarly, the energy storage modules 35 to 39 are also fixed between the center member 109 and the side member 102.Also in the example of FIGS. 11 and 12, the energy storage modules 30 to 39 may be fixed to the skeleton frame 100 by executing the additive decomposition process S 18 to the aging process S 20.In the first and second embodiments described above, an example in which a so-called prismatic battery is applied as an energy storage cell is explained. However, any various other energy storage cell may alternatively be applied as an energy storage cell. In the first and second embodiments described above, an example in which the width direction W, which is the horizontal direction, is the stacking direction of the energy storage cells is explained. However, the present invention can be applied also to an example in which the energy storage cells are stacked in the vertical direction.Third EmbodimentAn energy storage device 150 according to the third embodiment will be described below with reference to FIG. 13, etc. FIG. 13 shows a schematic perspective view of the energy storage device 150. In Fig. 13, the structure has been partially omitted for the purpose of visualizing the internal structure. The energy storage device 150 includes an accommodation case 151 and an energy storage unit 152.The accommodation case 151 includes a case body 153 and a cover 154. The case body 153 and the cover 154 are made of, for example, a metal material such as an aluminum alloy. The case body 153 is formed with an opening that is open upward, and the cover 154 is provided so as to close the opening of the case body 153.FIG. 14 is a schematic perspective view of the energy storage unit 152. The energy storage unit 152 has a plurality of energy storage modules 155 to 163.The energy storage modules 155 to 163 each have a plurality of energy storage cells 165. Here, the energy storage cells 165 of the energy storage modules 155 to 162 are stacked in the vertical direction. The energy storage cells 165 of the energy storage module 163 are arranged in the front-rear direction D of the vehicle 1.FIG. 15 is a plan view of the case body 153. The case body 153 includes a bottom plate 170, a peripheral wall portion 171, and a reinforcing member 175. The peripheral wall portion 171 is formed to extend upward from the outer peripheral edge portion of the bottom plate 170. The peripheral wall portion 171 is formed in an annular shape.The reinforcing member 175 is provided on an upper surface of the bottom plate 170. The reinforcing member 175 is formed in a frame shape. The reinforcing member 175 has an outer frame 176, a plurality of frames 177a to 177d, and a cross frame 178.The outer frame 176 is formed in an annular manner along an inner circumferential surface of the circumferential wall portion 171. The frames 177 ato 177 dare formed to extend in the front-rear direction D. The cross frame 178 is formed to extend in the width direction W.Accommodation spaces 180 ato 180 i, in which the energy storage modules 155 to 163 are respectively disposed, are formed by the frames.FIG. 16 shows a perspective view of the energy storage module 160 and the structure around the energy storage module 160. FIG. 17 shows a side view of the energy storage module 160 and the structure around the energy storage module 160.The energy storage module 160 includes the energy storage cells 165 and support plates 183, 184. The energy storage module 160 is formed in a rectangular parallelepiped shape and has a side surface 185 and a side surface 186. The side surface 185 is on the side of the outer frame 176 and the side surface 186 is on the side of the cross frame 178.The holding plate 183 is provided on the side surface 185, and the holding plate 184 is provided on the side surface 186.The holding plates 183 and 184 hold the energy storage cells 165 stacked in the vertical direction.Fasteners 181, 182 are provided on the holding plate 183 such that the holding plate 183 fixes the energy storage module 160 to the outer frame 176. The holding plate 183 is in contact with the outer frame 176. Alternatively, an insulation plate may be disposed between the holding plate 183 and the outer frame 176.On the other hand, the holding plate 184 is provided without a fastening means and spaced apart from the transverse frame 178.FIG. 18 shows a sectional view of the energy storage cell 165. The energy storage cell 165 includes a cell case 190 and a plurality of unit batteries 191.The cell case 190 is made of a metal material such as aluminum alloy. The unit batteries 191 are stacked in the vertical direction. The unit battery 191 includes an electrode assembly 192 and a packing member 193. The electrode assembly 192 is formed by sequentially stacking a positive electrode, a separator, and a negative electrode. The packing member 193 is formed by, for example, a laminated film. The electrode assembly 192 and an electrolyte solution (not shown) are disposed in the packing member 193.When the unit batteries 191 configured as described above deteriorate with the lapse of time, gas is accumulated in the packing members 193 so that the unit batteries 191 are deformed to expand. In this case, the unit batteries 191 are deformed to extend in the vertical direction and the horizontal direction. Therefore, the energy storage cells 165 and the energy storage module 160 are also deformed to expand in the vertical direction and in the horizontal direction.As shown in FIG. 17, since no fastening device is provided on the holding plate 184 of the energy storage module 160, the energy storage module 160 may deform to expand toward the cross frame 178.Since no fastener is provided on the side of the cross frame 178 of the energy storage module 160, even if the energy storage module 160 is deformed to expand toward the cross frame 178, adverse effects such as deformation of fasteners do not occur.FIG. 19 is a schematic sectional view showing a state in which the holding plate 184 of the energy storage module 160 is firmly pressed against the cross frame 178.In the state shown in FIG. 19, the holding plate 184 is firmly pressed against the cross frame 178, and the holding plate 183 is fixed to the outer frame 176. Therefore, even if the energy storage module 160 attempts to deform to expand in the front-rear direction D, the deformation of the energy storage module 160 is inhibited.In this manner, since the deformation of the energy storage module 160 is prevented, it is possible to prevent deformation of members provided on the energy storage module 160 or the like that would otherwise occur due to the deformation of the energy storage module 160.In addition, in the energy storage device 150 of the third embodiment, when the energy storage module 160 is disposed in the accommodation case 151, the accuracy of the size of the energy storage module 160 does not need to be so high, and therefore it is possible to reduce the manufacturing cost of the energy storage module 160.In the above-explained embodiments, an example in which the energy storage cell of a lithium ion battery is applied as an energy storage cell is described. Alternatively, for example, a capacitor cell or the like may be used instead of an energy storage cell.It should be noted that the embodiments disclosed above are for illustrative purposes only and do not limit the invention in any way. The scope of the invention is defined by the claims and is intended to include all changes within the meaning and range of equivalents of the claims. Further, the numerical values etc. explained above are for illustrative purposes only, and the present invention is not limited to the numerical values and the ranges thereof explained above.The energy storage device includes at least one energy storage module disposed between the first frame 22; 109; 176 and the second frame 20, 21; 101, 102; 178 spaced apart from each other, the energy storage module including a plurality of energy storage cells 42, 62; 165 disposed in succession, the first frame 22; 109; 176 and the second frame 20, 21; 101, 102; 178 being provided in a vehicle 1 or in the energy storage device 4; 150; and a fixing device, the energy storage module being fixed to the first frame 22; 109; 176 by the fixing device and not fixed to the second frame 20, 21; 101, 102; 178.

Claims

An energy storage device (4; 150) comprising: at least one energy storage module (30, 31, 32, 33, 34, 35, 36, 37, 38, 39; 155, 156, 157, 158, 159, 160, 161, 162, 163) disposed between a first frame (22; 109; 176) and a second frame (20, 21; 101, 102; 178) which are spaced apart from each other, wherein the energy storage module (30, 31, 32, 33, 34, 35, 36, 37, 38, 39; 155, 156, 157, 158, 159, 160, 161, 162, 163) has a plurality of energy storage cells (42, 62; 165) which are arranged in sequence, wherein the first frame (22; 109; 176) and the second frame (20, 21; 101, 102; 178) are provided in a vehicle (1) or the energy storage device (4; 150); and a fastening device (43, 44, 45, 46, 63, 64, 65, 66; 181, 182), wherein: the energy storage module (30, 31, 32, 33, 34, 35, 36, 37, 38, 39; 155, 156, 157, 158, 159, 160, 161, 162, 163) is fixed to the first frame (22; 109; 176) by the fixing device (43, 44, 45, 46, 63, 64, 65, 66; 181, 182) and is not fixed to the second frame (20, 21; 101, 102; 178); a plurality of the energy storage modules (30, 31, 32, 33, 34, 35, 36, 37, 38, 39) is provided in the energy storage device (4); the energy storage modules (30, 31, 32, 33, 34, 35, 36, 37, 38, 39) include a first energy storage module (30) and a second energy storage module (31); the energy storage modules (30, 31, 32, 33, 34, 35, 36, 37, 38, 39) further have a bus bar (53) that electrically connects the first energy storage module (30) and the second energy storage module (31) to each other; and the bus bar (53) is configured to connect a terminal of the first energy storage module (30) and a terminal of the second energy storage module (31) to each other, wherein the terminal of the first energy storage module (30) is a terminal on an end side of the first energy storage module (30) and is located on the side of the first frame, and wherein the terminal of the second energy storage module (31) is a terminal on an end side of the second energy storage module (31) and is located on the side of the first frame.The energy storage device (4; 150) according to claim 1, wherein the energy storage module (30, 31, 32, 33, 34, 35, 36, 37, 38, 39; 155, 156, 157, 158, 159, 160, 161, 162, 163) is pressed against the second frame (20, 21; 101, 102; 178) and is in contact with the second frame (20, 21; 101, 102; 178).The energy storage device (4; 150) according to claim 2, wherein upon expansion of the energy storage module (30, 31, 32, 33, 34, 35, 36, 37, 38, 39; 155, 156, 157, 158, 159, 160, 161, 162, 163), the energy storage module (30, 31, 32, 33, 34, 35, 36, 37, 38, 39; 155, 156, 157, 158, 159, 160, 161, 162, 163) is pressed against the second frame (20, 21; 101, 102; 178) and is in contact with the second frame (20, 21; 101, 102; 178).An energy storage device (4; 150) comprising: a first frame (22; 176) and a second frame (20, 21; 178) spaced apart from each other; at least one energy storage module (30, 31, 32, 33, 34, 35, 36, 37, 38, 39; 155, 156, 157, 158, 159, 160, 161, 162, 163) disposed between the first frame (22; 176) and the second frame (20, 21; 178), wherein the energy storage module (30, 31, 32, 33, 34, 35, 36, 37, 38, 39; 155, 156, 157, 158, 159, 160, 161, 162, 163) has a plurality of energy storage cells (42, 62; 165) arranged in sequence; and a fastener (43, 44, 45, 46, 63, 64, 65, 66; 181, 182), wherein: the energy storage module (30, 31, 32, 33, 34, 35, 36, 37, 38, 39; 155, 156, 157, 158, 159, 160, 161, 162, 163) has a first portion on a side of the first frame and a second portion on a side of the second frame; of the first portion and the second portion, the fixing means (43, 44, 45, 46, 63, 64, 65, 66; 181, 182) is provided only on the first portion; the fixing means (43, 44, 45, 46, 63, 64, 65, 66; 181, 182) fixes the energy storage module (30, 31, 32, 33, 34, 35, 36, 37, 38, 39; 155, 156, 157, 158, 159, 160, 161, 162, 163) to the first frame (22; 176); a plurality of the energy storage modules (30, 31, 32, 33, 34, 35, 36, 37, 38, 39) are provided in the energy storage device (4); the energy storage modules (30, 31, 32, 33, 34, 35, 36, 37, 38, 39) comprise a first energy storage module (30) and a second energy storage module (31); the energy storage modules (30, 31, 32, 33, 34, 35, 36, 37, 38, 39) further have a bus bar (53) that electrically connects the first energy storage module (30) and the second energy storage module (31) to each other; and the bus bar (53) is configured to connect a terminal of the first energy storage module (30) and a terminal of the second energy storage module (31) to each other, wherein the terminal of the first energy storage module (30) is a terminal on an end side of the first energy storage module (30) and is on the side of the first frame, and wherein the terminal of the second energy storage module (31) is a terminal on an end side of the second energy storage module (31) and is on the side of the first frame.The energy storage device (4; 150) according to claim 4, wherein the second portion is pressed against the second frame (20, 21; 178) and is in contact with the second frame (20, 21; 178).The energy storage device (4) according to any one of claims 1 to 5, wherein: the energy storage cells (42, 62) are arranged in sequence in a facing direction (W) in which the first frame (22) and the second frame (20, 21) face each other; the energy storage module (30, 31, 32, 33, 34, 35, 36, 37, 38, 39) has a holder (47, 67) that holds the energy storage cells (42, 62); the holder (47, 67) holds the energy storage cells (42, 62) such that the energy storage cells are arranged in sequence in the facing direction (W); and the holder (47, 67) is configured to deform in the facing direction (W).The energy storage device (150) according to any one of claims 1 to 5, wherein the energy storage cells (165) are arranged in sequence in an arrangement direction that is perpendicular to a direction in which the first frame (176) and the second frame (178) face each other.Vehicle (1) having at least one energy storage module (30, 31, 32, 33, 34, 35, 36, 37, 38, 39) according to one of Claims 1 to 7.

Images