Electricity storage device, exterior member for electricity storage device, electricity storage device assembly, electric vehicle, and method for manufacturing electricity storage device

Abstract

To provide a power storage device, a power storage device assembly, and an electric vehicle that can improve reliability.SOLUTION: In a power storage device 10 in which a power storage element 11 is sealed in an exterior member 20 of a laminate having a thermally adhesive resin layer 38 and mounted as a drive source in an electric vehicle 1, the exterior member 20 has a peripheral sealing portion 21 and a storage portion 16 formed at a predetermined depth from an inner edge of the peripheral sealing portion 21 and storing the power storage element 11, a depth direction (Z direction) of the storage portion 16 and an X direction orthogonal to the depth direction are arranged in a front-back direction or a left-right direction of the electric vehicle 1, and a Y-direction orthogonal to the depth direction (Z-direction) and orthogonal to the X-direction of the storage portion 16 is arranged in the height direction of the electric vehicle 1.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an electricity storage device to be mounted on an electric vehicle and a manufacturing method thereof. The present invention also relates to an exterior member for an electricity storage device used in an electricity storage device. The present invention also relates to an electricity storage device assembly and an electric vehicle using an electricity storage device. [Background technology]

[0002] In recent years, electric vehicles in which at least a portion of the driving force is supplied by a motor have been attracting attention from the viewpoints of environmental measures and resource conservation. These electric vehicles include electric vehicles (EVs), hybrid vehicles (HEVs), plug-in hybrid vehicles (PHEVs), etc. Electric vehicles are powered only by a motor, while hybrid vehicles and plug-in hybrid vehicles are powered by both a motor and an engine.

[0003] A conventional power storage device mounted on an electric vehicle is disclosed in Patent Document 1. This power storage device is composed of a thin secondary battery that is rectangular in plan view, with a battery element covered by an exterior member. The battery element is arranged with a positive electrode plate and a negative electrode plate facing each other with a separator interposed therebetween, and an electrolyte is disposed between the positive electrode plate and the negative electrode plate. The exterior member is formed by thermally bonding two laminates having metal foils with a thermal adhesive resin layer to enclose the battery element. At this time, terminals connected to the positive electrode plate and the negative electrode plate protrude from the exterior member.

[0004] The power storage devices are stacked in the thickness direction and arranged side by side in the short direction of a rectangle in a plan view to form a battery pack consisting of a plurality of power storage devices. The battery packs are also stacked in the thickness direction of the power storage devices, and a composite battery pack consisting of a plurality of battery packs is installed under the floor of an electric vehicle. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 3719235 (pages 4 to 11, Figure 7) Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the conventional power storage devices described above, the weight of the upper power storage device is added to the lower power storage device because the devices are stacked in the height direction when mounted on the vehicle. This causes the exterior member made of the laminate to deform, and when the load increases due to vibration of the vehicle, the exterior member may be damaged. This causes a problem of reduced reliability of the power storage device and the electric vehicle.

[0007] The present invention aims to provide an electricity storage device, an electricity storage device assembly, and an electric vehicle that can improve reliability. It is also an object of the present invention to provide an exterior member for an electricity storage device used in the electricity storage device, and a method for manufacturing the electricity storage device, that can improve reliability. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, the present invention provides an energy storage device that has an energy storage element encapsulated in an exterior member of a laminate having a thermal adhesive resin layer and is installed in an electric vehicle as a driving source, the exterior member having a peripheral seal portion and a storage portion that is formed at a predetermined depth from the inner edge of the peripheral seal portion and that stores the energy storage element, wherein a depth direction of the storage portion and a first direction perpendicular to the depth direction of the storage portion are arranged in the front-rear or left-right direction of the electric vehicle, and a second direction perpendicular to the depth direction of the storage portion and the first direction is arranged in the height direction of the electric vehicle.

[0009] In the electricity accumulation device of the present invention configured as described above, the length of the storage section in the first direction is greater than the length of the storage section in the second direction.

[0010] Furthermore, in the electricity accumulation device of the present invention configured as described above, the length of the storage section in the first direction is 2 to 30 times the length of the storage section in the second direction.

[0011] Furthermore, in the electricity accumulation device of the present invention configured as described above, the peripheral seal portion extending in the first direction is folded to be superimposed on the peripheral wall of the storage portion.

[0012] Furthermore, in the electricity storage device of the present invention having the above-described configuration, a flow direction of the exterior member is perpendicular to the first direction.

[0013] The present invention is also characterized in that, in the energy storage device having the above-mentioned configuration, the energy storage element has a first electrode terminal and a second electrode terminal, and the first electrode terminal and the second electrode terminal protrude from the peripheral seal portion extending in the second direction.

[0014] In the electricity storage device of the present invention having the above-mentioned configuration, the first electrode terminal protrudes from one of the peripheral seal portions facing in the first direction, and the second electrode terminal protrudes from the other.

[0015] The present invention is also characterized in that, in an electricity storage device assembly to be mounted on an electric vehicle, a plurality of electricity storage devices having the above-described configurations are arranged side by side in the depth direction of the storage section and stored in an outer container, and the length in the direction in which the plurality of electricity storage devices are arranged side by side is greater than the length in the second direction.

[0016] In the present invention, in the electricity storage device assembly configured as described above, the length in the first direction is greater than the length in the direction in which the plurality of electricity storage devices are arranged side by side.

[0017] In the present invention, the electricity storage device assembly having the above-mentioned configuration further comprises a mounting member on which the outer container is placed, the mounting member having a temperature adjusting function.

[0018] Furthermore, according to the present invention, in the electricity storage device assembly configured as described above, the assembly further comprises a mounting member on which the outer container is placed, the mounting member being formed from a liquid absorbent material.

[0019] Moreover, an electric vehicle of the present invention comprises an electricity storage device assembly having the above-described configuration, a drive motor supplied with power from the electricity storage device assembly, and wheels driven by the drive motor, and is characterized in that the electricity storage device assembly is arranged in a single layer in the height direction at the bottom of the vehicle body.

[0020] The present invention also relates to an exterior component for an electricity storage device that encapsulates an electricity storage element of an electricity storage device installed in an electric vehicle as a driving source, and is characterized in that the exterior component has a thermally adhesive resin layer, the exterior component has an opening on one side and is formed to a predetermined depth, the exterior component has a storage section that stores the electricity storage element, and a flange section that protrudes outward from the periphery of the opening, the length of the storage section in a predetermined first direction in a plane perpendicular to the depth direction of the storage section is greater than the length of a second direction perpendicular to the first direction, and the flow direction of the laminate is perpendicular to the first direction.

[0021] Moreover, the present invention is characterized in that, in the exterior member for an electricity storage device configured as described above, the length of the storage section in the first direction is 2 to 30 times the length in the second direction.

[0022] The present invention also provides a method for manufacturing an electricity storage device to be installed in an electric vehicle as a driving source, the method comprising the steps of: preparing an exterior member having a storage section made of a laminate having a thermal adhesive resin layer; and storing an electricity storage element in the storage section and packaging it with the exterior member, wherein a depth direction of the storage section and a first direction perpendicular to the depth direction of the storage section are arranged in the front-to-rear or left-to-right direction of the electric vehicle, a second direction perpendicular to the depth direction of the storage section and the first direction is arranged in the height direction of the electric vehicle, and the length of the storage section in the first direction is greater than the length of the storage section in the second direction.

[0023] Furthermore, in the method for producing an electricity accumulation device configured as described above, the present invention is characterized in that the length of the storage section in the first direction is 2 to 30 times the length of the storage section in the second direction.

[0024] Furthermore, the present invention is characterized in that in the method for manufacturing an electricity storage device having the above-mentioned configuration, the process of packaging with the exterior member includes forming a peripheral seal portion on the periphery of the exterior member by thermal bonding of the thermal adhesive resin layer, and folding the peripheral seal portion extending in the second direction to overlap the peripheral wall of the storage portion.

[0025] In addition, in the manufacturing method for an electricity accumulation device according to the present invention configured as described above, the first direction is perpendicular to a flow direction of the exterior member. Effect of the Invention

[0026] According to the present invention, the power storage device is arranged in the depth direction of the storage section of the exterior member and in a first direction perpendicular to the depth direction in the front-rear or left-right direction of the electric vehicle. Also, the depth direction of the storage section and a second direction perpendicular to the first direction are arranged in the height direction of the electric vehicle. This allows a plurality of power storage devices to be installed in the electric vehicle without being stacked to supply the desired power. This makes it possible to prevent damage to the exterior member due to the weight applied when stacked, and improve the reliability of the power storage device, the power storage device assembly, and the electric vehicle.

[0027] The exterior member for an electricity storage device of the present invention is formed of a laminate and has a storage section and a flange section. In addition, in a plane perpendicular to the depth direction of the storage section, the length of the storage section in a first direction is greater than the length in a second direction perpendicular to the first direction, and the flow direction of the laminate is perpendicular to the first direction. As a result, a peripheral seal section is formed by thermally bonding the flange section, and pinholes and cracks in the exterior member for an electricity storage device can be reduced when the peripheral seal section extending in the first direction is bent. Therefore, the yield of electricity storage devices can be improved. [Brief description of the drawings]

[0028] [Figure 1] FIG. 1 is a side view showing an electric vehicle according to a first embodiment of the present invention; [Diagram 2] FIG. 1 is a top view showing an electric vehicle according to a first embodiment of the present invention; [Diagram 3]FIG. 1 is a perspective view showing an electricity storage device pack for an electric vehicle according to a first embodiment of the present invention; [Figure 4] FIG. 1 is an exploded perspective view showing an electric storage device for an electric vehicle according to a first embodiment of the present invention; [Diagram 5] FIG. 1 is a side cross-sectional view showing an electric storage device for an electric vehicle according to a first embodiment of the present invention; [Figure 6] FIG. 1 is a cross-sectional view showing a packaging material for an exterior member of an electricity storage device of an electric vehicle according to a first embodiment of the present invention. [Figure 7] FIG. 13 is an exploded perspective view showing an electric storage device for an electric vehicle according to a second embodiment of the present invention. [Figure 8] FIG. 11 is a side cross-sectional view showing an electric storage device for an electric vehicle according to a second embodiment of the present invention. [Figure 9] FIG. 11 is a side cross-sectional view showing a state in which the power storage device of the electric vehicle according to the second embodiment of the present invention is covered with a protective cover. [Figure 10] FIG. 11 is a side cross-sectional view showing a state in which the power storage device of the electric vehicle according to the second embodiment of the present invention is covered with another protective cover. [Figure 11] FIG. 13 is an exploded perspective view showing an electric storage device for an electric vehicle according to a third embodiment of the present invention. [Figure 12] FIG. 11 is a top view showing an electric vehicle according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] First Embodiment Hereinafter, embodiments of the present invention will be described with reference to the drawings. Figures 1 and 2 show a side view and a top view of an electric vehicle 1 of a first embodiment. The electric vehicle 1 is equipped with a drive motor 3 as a power source for driving wheels 2. Under the floor of the body of the electric vehicle 1, an electricity storage device pack 5 (an assembly of electricity storage devices) is installed as a drive source for supplying electricity to the drive motor 3.

[0030] 3 shows a perspective view of an electricity storage device pack 5. The electricity storage device pack 5 has a plurality of electricity storage devices 10 arranged side by side, and is covered by an outer container 6. The electricity storage device pack 5 may be configured by arranging a plurality of electricity storage device modules, each of which packages a plurality of electricity storage devices 10, side by side.

[0031] A positive electrode terminal 12 and a negative electrode terminal 13 (see FIG. 4) made of metal are provided on each power storage device 10. The electrode terminals 12 and 13 are electrically connected in a predetermined order, and a pair of connection terminals (not shown) protrude from the outer container 6.

[0032] The outer container 6 is formed of a laminate in which a thermal adhesive resin layer, a metal foil, and a base material layer are laminated. A filler (not shown) is filled into the space between each of the electricity storage devices 10 and the outer container 6, and the thermal adhesive resin layer is thermally bonded to seal the outer container 6. The outer container 6 may be formed by injection molding.

[0033] 4 and 5 show an exploded perspective view and a side cross-sectional view of the electricity storage device 10. The electricity storage device 10 is composed of a secondary battery in which an electricity storage element 11 is enclosed in an exterior member 20. As the electricity storage device 10, for example, a lithium ion battery, a lithium ion polymer battery, a lithium ion all-solid-state battery, a lead storage battery, a nickel-metal hydride storage battery, a nickel-cadmium storage battery, a nickel-iron storage battery, a nickel-zinc storage battery, a silver oxide zinc storage battery, a metal-air battery, a polyvalent cation battery, or the like can be used.

[0034] The energy storage element 11 is formed by arranging a positive electrode plate and a negative electrode plate (both not shown) facing each other with an insulating separator (not shown) interposed therebetween. Electrode terminals 12, 13 are connected to the positive electrode plate and the negative electrode plate, respectively. The energy storage element 11 can be formed by winding a long separator, a positive electrode plate, and a negative electrode plate. The energy storage element 11 may also be formed by stacking a sheet-like positive electrode plate, a separator, a negative electrode plate, and a separator in this order in multiple stages. The energy storage element 11 may also be formed by stacking a long separator, a positive electrode plate, and a negative electrode plate by folding.

[0035] An electrolyte is disposed between the positive electrode plate and the negative electrode plate. In this embodiment, the electrolyte is an electrolytic solution, and is filled inside the exterior member 20. A solid electrolyte or a gel electrolyte may be used as the electrolyte.

[0036] The exterior member 20 includes a packaging material 15 (first packaging material) and a packaging material 25 (second packaging material) made of a laminate having a thermal adhesive resin layer 38 (see FIG. 6) on the inner surface.

[0037] 6 is a cross-sectional view showing the layered structure of packaging material 15. Packaging material 25 has the same layered structure as packaging material 15. Packaging material 15 and packaging material 25 are formed by sequentially layering a base material layer 34, a barrier layer 36, and a thermal adhesive resin layer 38. The thickness of packaging material 15 and packaging material 25 is desirably 50 μm or more in consideration of strength, and desirably 400 μm or less in consideration of reducing the weight of electricity storage device 10.

[0038] The base layer 34 has insulating properties and is formed of a resin film such as nylon, polyester, polyethylene terephthalate, etc. The thickness of the base layer 34 is, for example, 10 μm or more and 75 μm or less. To improve heat resistance, it is more desirable to form the base layer 34 from a uniaxially stretched film or a biaxially stretched film.

[0039] In order to improve pinhole resistance, insulation, etc., the base material layer 34 may be formed by laminating multiple resin films made of different materials. At this time, the multiple resin films are bonded with an adhesive such as a polyurethane-based or acrylic-based adhesive. In this embodiment, the base material layer 34 is formed by laminating polyethylene terephthalate (thickness 12 μm) and nylon (thickness 15 μm) with an adhesive (thickness 4 μm).

[0040] The barrier layer 36 is formed of a metal foil and prevents the intrusion of water vapor, oxygen, light, and the like. Examples of metals that can be used to form the barrier layer 36 include aluminum, aluminum alloy, stainless steel, and titanium. The barrier layer 36 is formed to a thickness of, for example, 10 μm or more and 300 μm or less. The base layer 34 and the barrier layer 36 are bonded together with an adhesive (not shown) such as a polyurethane-based or acrylic-based adhesive. In this embodiment, the barrier layer 36 is formed of an aluminum foil having a thickness of 40 μm.

[0041] The thermal adhesive resin layer 38 may be any resin having thermal adhesive properties, and is formed of a thermal adhesive resin such as polypropylene, acid-modified polypropylene, low-density polyethylene, linear low-density polyethylene, etc. The thermal adhesive resin layer 38 may be formed by laminating a plurality of resins of different materials. The thermal adhesive resin layer 38 is formed to a thickness of, for example, 10 μm or more and 100 μm or less. The thermal adhesive resin layer 38 is formed by extrusion on the barrier layer 36. The film forming the thermal adhesive resin layer 38 may be bonded onto the barrier layer 36 with an adhesive.

[0042] In this embodiment, the thermal adhesive resin layer 38 is formed by extruding an acid-modified polypropylene (thickness: 40 μm) and a polypropylene (thickness: 40 μm) in this order onto the barrier layer 36 .

[0043] 4 and 5, packaging material 25 is formed into a rectangular sheet shape. Packaging material 15 has a storage section 16 and a flange section 17. Storage section 16 has a substantially rectangular opening 16a on one side, and stores energy storage element 11. Flange section 17 is formed into an annular shape protruding from the periphery of opening 16a toward the outer periphery.

[0044] The flange portion 17 and the facing heat-adhesive resin layer 38 (see FIG. 6) of the packaging material 25 are heat-adhered to form a ring-shaped peripheral seal portion 21 (see FIG. 5) along the periphery of the storage portion 16. As a result, the storage portion 16 is formed to a predetermined depth from the inner edge of the peripheral seal portion 21 and is sealed by the peripheral seal portion 21.

[0045] The packaging material 15 is formed by forming the storage section 16 by recessing the storage section 16 to a predetermined depth in the flange section 17. At this time, the storage section 16 is formed into a substantially rectangular shape extending in one direction within a plane perpendicular to the depth direction.

[0046] The depth of the storage section 16 is determined according to the thickness of the barrier layer 36 of the packaging material 15 so that cracks and the like do not occur during molding. In this embodiment, the depth of the storage section 16 is formed to be 5 mm to 10 mm for a barrier layer 36 with a thickness of 40 μm. At this time, the corner R of each corner in a plane perpendicular to the depth direction of the storage section 16 is formed to be, for example, about 3 mm, and the corner R of each corner in a plane parallel to the depth direction is formed to be, for example, about 1.5 mm. Note that by increasing the thickness of the barrier layer 36, the depth of the storage section 16 can be formed to be, for example, 5 mm to 30 mm.

[0047] The power storage device 10 is disposed so that the depth direction (Y direction) of the storage section 16 corresponds to the front-rear direction of the electric vehicle 1. The longitudinal direction (X direction, first direction) of a plane perpendicular to the depth direction of the storage section 16 corresponds to the left-right direction of the electric vehicle 1, and the short side direction (Z direction, second direction) corresponds to the height direction of the electric vehicle 1. That is, the X direction perpendicular to the depth direction of the storage section 16 corresponds to the left-right direction of the electric vehicle 1, and the Z direction perpendicular to the depth direction and X direction of the storage section 16 corresponds to the height direction of the electric vehicle 1.

[0048] Since the storage section 16 is formed by sheet molding, it is difficult to increase the depth. In contrast, the lengths Ax and Az of the storage section 16 in two directions perpendicular to each other in a plane perpendicular to the depth direction can be easily made greater than the length Ay in the depth direction. For this reason, by arranging the depth direction (Y direction) of the storage section 16 in the front-rear direction of the electric vehicle 1, a plurality of electricity storage devices 10 can be installed on the electric vehicle 1 without being stacked to supply the desired power. Therefore, damage to the exterior member 20 due to the weight when stacked can be prevented, and the reliability of the electricity storage device 10 can be improved.

[0049] In addition, when the electrolyte is made of an electrolytic solution, stacking the electricity storage devices 10 in the depth direction (Y direction) of the storage section 16 causes the packaging material 25 to bend under weight, pushing the electrolytic solution out to the periphery. This causes a shortage of electrolytic solution between the positive and negative plates in the center, lowering the energy density of the electricity storage device 10. Therefore, by arranging the depth direction (Y direction) of the storage section 16 in the front-to-rear direction, it is possible to prevent a decrease in the energy density of the electricity storage device 10 containing the electrolytic solution.

[0050] Furthermore, since the short side direction (Z direction) in a plane perpendicular to the depth direction of the storage section 16 is arranged in the height direction, it is possible to reduce the height of the electricity storage device 10 and improve the livability of the electric vehicle 1. At this time, since the storage section 16 extends long in the X direction and the length Ax in the X direction is greater than the length Az in the Z direction, it is possible to obtain an electricity storage device 10 with a large capacity by suppressing the height.

[0051] The length Ax of the storage section 16 in the X direction is formed to be 2 to 30 times the length Az in the Z direction. If the length Ax is less than twice the length Az, the capacity of the electricity storage device 10 will be small. For this reason, the length Ax is formed to be twice or more the length Az, so that the capacity of the electricity storage device 10 can be increased. If the length Ax exceeds 30 times the length Az, the packaging material 15 cannot be easily molded, so that the yield decreases. For this reason, the length Ax is formed to be 30 times or less the length Az, so that the yield during molding of the packaging material 15 can be improved.

[0052] Furthermore, the peripheral seal portion 21 extending in the X direction protrudes in the Z direction as indicated by the dashed dotted line 21' during thermal bonding, and is folded after thermal bonding to be superimposed on the peripheral wall of the storage portion 16. This allows the height of the electricity storage device 10 to be made smaller.

[0053] At this time, the machine direction (MD) of the packaging materials 15, 25 made of the laminate is arranged in the Z direction (perpendicular to the X direction). If the laminate is folded parallel to the machine direction, there is a high possibility that cracks will occur in the metal foil and pinholes will occur in the resin film. Because the machine direction of the packaging materials 15, 25 is perpendicular to the X direction, it is possible to suppress the occurrence of cracks and pinholes in the exterior member 20 when the peripheral seal portion 21 extending in the X direction is folded.

[0054] The machine direction (MD) of the packaging materials 15, 25 corresponds to the rolling direction (RD) of the metal foil (aluminum alloy foil, etc.) of the barrier layer 36. The TD of the packaging materials 15, 25 corresponds to the TD of the metal foil. The rolling direction (RD) of the metal foil can be determined by the rolling marks.

[0055] In addition, the sea-island structure can be confirmed by observing multiple cross sections of the thermal adhesive resin layer 38 of the packaging material 15, 25 with an electron microscope, and the MD can be determined as the direction parallel to the cross section in which the average island diameter in the direction perpendicular to the thickness direction of the thermal adhesive resin layer 38 was maximum. When the MD of the packaging material 15, 25 cannot be identified based on the rolling marks of the metal foil, the MD can be identified by this method.

[0056] Specifically, the sea-island structure is confirmed by observing the longitudinal cross section of the thermal adhesive resin layer 38 and each cross section (a total of 10 cross sections) at an angle of 10 degrees from the direction parallel to the longitudinal cross section and perpendicular to the longitudinal cross section. Next, for each island on each cross section, the island diameter d is measured based on the linear distance connecting both ends in the direction perpendicular to the thickness direction of the thermal adhesive resin layer 38. Next, the average of the diameters d of the top 20 largest islands is calculated for each cross section. The direction parallel to the cross section in which the average island diameter d was the largest is determined to be the MD.

[0057] The electrode terminals 12 and 13 extend in the Z direction and protrude from peripheral seal parts 21 that face each other in the X direction. This allows the height of the electricity storage device 10 to be made lower. Furthermore, the electrode terminal 12 protrudes from one of the peripheral seal parts 21 that face each other in the X direction, and the electrode terminal 13 protrudes from the other. If the electrode terminals 12 and 13 are close to each other, the temperature rise in the vicinity of the electrode terminals 12 and 13 increases, making the electricity storage device 10 prone to deterioration over time. For this reason, by arranging the electrode terminals 12 and 13 apart in the X direction, it is possible to suppress deterioration over time of the electricity storage device 10.

[0058] The electricity storage device 10 is manufactured by a step of preparing a molded exterior member 20, followed by a packaging step of packaging the electricity storage elements 11 in the exterior member 20. Furthermore, a folding step is provided after the packaging step, if necessary.

[0059] In the forming process for forming the exterior member 20, the roll-shaped laminate is cut to a predetermined length, and the storage section 16 is recessed into the flange section 17 by cold forming to form the packaging material 15. At this time, the packaging materials 15, 25 are formed with the machine direction (MD) of the roll-shaped laminate aligned in the Z direction. The exterior member 20 may be prepared by a forming process, or a formed exterior member 20 may be obtained and then prepared.

[0060] In the packaging process, the electrode terminals 12, 13 are arranged on the flange portion 17, the energy storage element 11 is stored in the storage portion 16, and the storage portion 16 is filled with an electrolyte. Next, the packaging material 25 is thermally bonded to the flange portion 17 of the packaging material 15 to form a peripheral seal portion 21 along the periphery of the storage portion 16, thereby sealing the storage portion 16. As a result, the energy storage element 11 is packaged in the exterior member 20.

[0061] In the folding process, the peripheral seal portion 21 extending in the X direction perpendicular to the flow direction of the laminate is folded and overlapped on the peripheral wall of the storage portion 16 .

[0062] 3, the electricity storage device pack 5 is formed by arranging a plurality of electricity storage devices 10 side by side in the Y direction and is installed in the electric vehicle 1 in a single stage in the height direction. Note that a plurality of electricity storage device packs 5 may be installed in the electric vehicle 1 lined up in the X direction or the Y direction.

[0063] The Z-direction length Bz of the electricity storage device pack 5 is formed to be approximately the same as the Z-direction length Az of the storage section 16 of the electricity storage device 10. The X-direction length Bx of the electricity storage device pack 5 is formed to be approximately the same as the X-direction length of the electricity storage device 10. In addition, since the electricity storage devices 10 are arranged side by side in the Y direction, the Y-direction length By of the electricity storage device pack 5 is greater than the Z-direction length Bz.

[0064] When the electric vehicle 1 is a sedan or compact car type, the height (length Bz in the Z direction) of the electricity storage device pack 5 is set to, for example, 100 mm or less. When the electric vehicle 1 is an SUV or a minivan type, the height (length Bz in the Z direction) of the electricity storage device pack 5 is set to, for example, 150 mm or less.

[0065] Furthermore, although the length By in the Y direction of the electricity storage device pack 5 differs depending on the number of electricity storage devices 10, it is preferable to form the length Bx in the X direction to be greater than the length By in the Y direction. This makes it possible to obtain a large-capacity electricity storage device pack 5 by reducing the number of electricity storage devices 10.

[0066] According to this embodiment, the depth direction (Y direction) of the storage section 16 of the exterior member 20 of the power storage device 10 is disposed in the front-rear direction of the electric vehicle 1. In addition, the X direction (first direction) perpendicular to the depth direction of the storage section 16 is disposed in the left-right direction of the electric vehicle 1. The Z direction (second direction) perpendicular to the depth direction and X direction of the storage section 16 is disposed in the height direction of the electric vehicle 1. That is, the X direction (first direction) and Z direction (second direction) perpendicular to each other in a plane perpendicular to the depth direction of the storage section 16 are disposed in the left-right direction and height direction of the electric vehicle 1, respectively.

[0067] This allows a plurality of electricity storage devices 10 to be installed in the electric vehicle 1 without being stacked to supply the desired power. This prevents damage to the exterior member 20 due to the weight applied when stacked, improving the reliability of the electricity storage device 10. Furthermore, when the electricity storage device 10 contains an electrolyte, the depth direction (Y direction) of the storage section 16 can be arranged in the front-rear direction to prevent a decrease in the energy density of the electricity storage device 10.

[0068] Moreover, since the short side direction (Z direction) in a plane perpendicular to the depth direction of the storage section 16 is arranged in the height direction, the length Ax in the X direction of the storage section 16 is greater than the length Az in the Z direction. This makes it possible to reduce the height of the electricity storage device 10 and improve the habitability of the electric vehicle 1, and also makes it possible to obtain an electricity storage device 10 with a large capacity.

[0069] Furthermore, since the length Ax of the storage section 16 in the X direction is 2 to 30 times the length Az in the Z direction, an electricity storage device 10 with a large capacity can be obtained and the yield of the exterior member 20 can be improved.

[0070] Furthermore, since the peripheral seal portion 21 extending in the X direction is folded and overlapped on the peripheral wall of the storage section 16, the height of the electricity storage device 10 can be made lower.

[0071] Furthermore, since the flow direction of the packaging materials 15, 25 is perpendicular to the X direction, it is possible to suppress the occurrence of cracks and pinholes in the exterior member 20 when the peripheral seal portion 21 extending in the X direction is folded.

[0072] Furthermore, since the electrode terminals 12 and 13 protrude from the peripheral seal portion 21 extending in the Z direction, the height of the electricity storage device 10 can be made lower.

[0073] Furthermore, since the electrode terminal 12 protrudes from one of the peripheral seal portions 21 facing each other in the X direction, and the electrode terminal 13 protrudes from the other, deterioration of the electricity storage device 10 over time can be suppressed.

[0074] Furthermore, the electricity storage device pack 5 (electricity storage device assembly) is formed by arranging the electricity storage devices 10 side by side in the depth direction (Y direction) of the storage section 16, and the length By of the electricity storage device pack 5 in the Y direction is greater than the length Bz in the Z direction. This allows the height of the electricity storage device pack 5 to be reduced, thereby enabling the desired power to be supplied.

[0075] Furthermore, since the electricity storage device packs 5 are installed in a single layer in the height direction of the electric vehicle 1, the livability of the electric vehicle 1 can be improved.

[0076] <Second embodiment> Next, Fig. 7 and Fig. 8 show an exploded perspective view and a side cross-sectional view of an electricity storage device 10 according to a second embodiment. For ease of explanation, the same parts as those in the first embodiment shown in Figs. 1 to 6 are denoted by the same reference numerals. This embodiment differs from the first embodiment in the shape of the packaging material 25, but the other parts are the same as those in the first embodiment.

[0077] Similar to packaging material 15, packaging material 25 has a storage section 26 and a flange section 27. Storage section 26 has a substantially rectangular opening 26a on one side. Energy storage elements 11 are stored in storage section 16 of packaging material 15 and storage section 26 of packaging material 25. Flange section 27 is formed in an annular shape protruding outward from the periphery of opening 26a.

[0078] The heat-adhesive resin layer 38 (see FIG. 6) of the flange portion 17 and the flange portion 27 is heat-adhesive to form a ring-shaped peripheral seal portion 21 along the periphery of the storage portion 16 and the storage portion 26. As a result, the storage portion 16 and the storage portion 26, which are formed at a predetermined depth from the inner edge of the peripheral seal portion 21, are sealed by the peripheral seal portion 21.

[0079] Moreover, the peripheral seal portion 21 extending in the X direction protrudes in the Z direction as indicated by the dashed line 21' during thermal bonding, and is folded and overlapped on the peripheral wall of the storage portion 16 or the storage portion 26 after thermal bonding.

[0080] The power storage device 10 is disposed such that the depth direction (Y direction) of the storage sections 16, 26 corresponds to the front-rear direction of the electric vehicle 1. The longitudinal direction (X direction) of a plane perpendicular to the depth direction of the storage sections 16, 26 corresponds to the left-right direction of the electric vehicle 1, and the short side direction (Z direction) corresponds to the height direction of the electric vehicle 1.

[0081] This makes it possible to obtain the same effects as in the first embodiment. Furthermore, since the packaging material 15 and the packaging material 25 respectively include the storage section 16 and the storage section 26, it is possible to increase the volume of the energy storage element 11 and increase the capacity of the energy storage device 10. This makes it possible to reduce the number of energy storage devices 10 forming the energy storage device pack 5 (see FIG. 3 ), and thus reduce the number of steps required to manufacture the energy storage device pack 5.

[0082] 9, the electricity storage device 10 may be covered with protective covers 8 and 9. The protective covers 8 and 9 are formed by injection molding into a cylindrical shape with a rectangular cross section and a bottom, with an opening on one side. In addition, the outer shape of the protective cover 9 is formed to be smaller than the opening of the protective cover 8.

[0083] Peripheral seal portion 21 protruding from the periphery of exterior member 20 is bent along the peripheral wall of protective cover 9, and protective cover 8 is fitted onto protective cover 9 along peripheral seal portion 21. As a result, peripheral seal portion 21 is bent at a position away from the periphery of openings 16a, 26a (see FIG. 7) of storage sections 16, 26. This makes it possible to reduce the occurrence of cracks and pinholes due to bending of peripheral seal portion 21.

[0084] FIG. 10 shows an electricity storage device 10 covered with protective covers 8, 9 having a different shape from that shown in FIG. The protective covers 8, 9 are formed by injection molding in substantially the same shape, and are formed into a bottomed cylindrical shape with an opening on one side. The folding process is omitted for the electricity storage device 10, and the protective covers 8, 9 are fixed in a state in which the peripheral seal portion 21 protruding from the periphery of the exterior member 20 is sandwiched between the peripheral walls of the protective covers 8, 9. This protects the peripheral seal portion 21. Because the folding process is omitted, the occurrence of cracks and pinholes due to bending of the peripheral seal portion 21 can be reduced.

[0085] Incidentally, in the electricity accumulation device 10 of the first embodiment, the exterior member 20 may also be covered with similar protective covers 8 and 9.

[0086] <Third embodiment> Next, Fig. 11 shows an exploded perspective view of an electricity storage device 10 according to a third embodiment. For ease of explanation, the same parts as those in the second embodiment shown in Figs. 7 and 8 above are denoted by the same reference numerals. In this embodiment, the packaging material 15 and the packaging material 25 are formed from a single member. The other parts are the same as those in the second embodiment.

[0087] In the exterior member 20, a packaging material 15 having a storage portion 16 and a packaging material 25 having a storage portion 26 are formed continuously and integrally in the Z direction. A flange portion 17 of the packaging material 15 and a flange portion 27 of the packaging material 25 are formed flush with each other via a folding line 20a.

[0088] After placing energy storage device 11 in storage portion 16 or storage portion 26, exterior member 20 is folded along folding line 20a extending in the X direction. Then, opposing flange portions 17, 27 are thermally bonded to form peripheral seal portion 21.

[0089] This embodiment can provide the same effects as those of the second embodiment. In addition, since the packaging material 15 and the packaging material 25 are formed from a single member, the number of parts of the electricity storage device 10 can be reduced.

[0090] In this embodiment, the openings 16a, 26a may be disposed close to each other, and the fold line 20a may be provided along the periphery of the openings 16a, 26a. This allows the lower surface of the electricity storage device 10 to be formed flat. This increases the adhesion between the installation surface on which the electricity storage device 10 is installed and the electricity storage device 10, thereby improving the heat dissipation property of the electricity storage device 10.

[0091] The packaging material 15 and the packaging material 25 in the first and second embodiments may be formed from a single member that is connected via a fold line at the bottom end.

[0092] <Fourth embodiment> Next, Fig. 12 shows a top view of an electric vehicle 1 according to a fourth embodiment. For ease of explanation, the same parts as those in the first embodiment shown in Figs. 1 to 6 described above are given the same reference numerals. This embodiment differs from the first embodiment in the arrangement of the electricity storage device pack 5. The other parts are the same as those in the first embodiment.

[0093] The electricity storage device pack 5 is installed under the floor of the body of the electric vehicle 1, and the electricity storage devices 10 are arranged side by side in the left-right direction of the electric vehicle 1. As a result, the electricity storage devices 10 are arranged in the depth direction (Y direction) of the storage section 16 (see FIG. 4) in the left-right direction of the electric vehicle 1. Furthermore, the longitudinal direction (X direction, first direction) in a plane perpendicular to the depth direction of the storage section 16 is arranged in the front-rear direction of the electric vehicle 1, and the short side direction (Z direction, second direction) is arranged in the height direction of the electric vehicle 1. In other words, the X direction perpendicular to the depth direction of the storage section 16 is arranged in the front-rear direction of the electric vehicle 1, and the Z direction perpendicular to the depth direction and X direction of the storage section 16 is arranged in the height direction of the electric vehicle 1.

[0094] This allows a plurality of power storage devices 10 to be installed in the electric vehicle 1 without being stacked, and to supply the desired power. Therefore, the same effect as in the first embodiment can be obtained. Furthermore, when the electric vehicle 1 is traveling, air taken in through the front grille flows rearward and comes into contact with each power storage device 10 in the power storage device pack 5. This allows the power storage devices 10 to be cooled.

[0095] The electricity storage devices 10 of the second or third embodiment may be installed in the electric vehicle 1, and the electricity storage devices 10 may be arranged in parallel in the left-right direction of the electric vehicle 1.

[0096] In the first to fourth embodiments, the cross-sectional shape of the storage sections 16, 26 perpendicular to the Y direction is formed to be substantially rectangular, but it may be other shapes such as an oval, an ellipse, or a polygon.

[0097] Furthermore, the outer container 6 of the electricity storage device pack 5 may be placed on a mounting member having a temperature adjustment function. For example, the mounting member may be formed of a metal plate to dissipate heat from the electricity storage device pack 5 and suppress a temperature rise in the electricity storage device 10. At this time, circulating water may be circulated through the mounting member. Furthermore, when the electricity storage device 10 is an all-solid-state battery or the like, a heater may be provided on the mounting member, and the electricity storage device 10 may be maintained at an appropriate temperature by turning the heater on and off.

[0098] Furthermore, the outer container 6 of the electricity storage device pack 5 may be placed on a mounting member made of a liquid absorbent material. For example, the mounting member may be made of a nonwoven fabric, and when electrolyte leaks from the electricity storage device pack 5, the electrolyte can be absorbed by the mounting member.

[0099] Furthermore, the power storage device 10 that supplies power to the drive motor 3 is made up of a secondary battery, but may also be a capacitor (such as an electrolytic capacitor, an electric double layer capacitor, or a lithium ion capacitor). [Industrial Applicability]

[0100] The present invention can be widely used in electric vehicles equipped with electricity storage devices. [Explanation of symbols]

[0101] 1 Electric vehicle 2 wheels 3 Drive motor 5. Energy storage device pack 6 Outer packaging 10. Energy storage devices 11 Energy storage element 12, 13 Electrode terminal 15, 25 Packaging materials 16, 26 Storage area 16a, 26a opening 17, 27 Flange part 20 Exterior materials 20a Fold line 21 Periphery seal 34 Base material layer 36 Barrier Layer 38 Thermal adhesive resin layer

Claims

1. An electricity storage device, which is mounted as a driving source in an electric vehicle, includes an electricity storage element encapsulated in an exterior member of a laminate having a base layer, a barrier layer, and a thermal adhesive resin layer, and is configured as follows: the substrate layer comprises a single-layer or multi-layer resin film of any one of nylon, polyester, and polyethylene terephthalate, the barrier layer comprises a metal foil of any one of aluminum, aluminum alloy, and stainless steel, the thermal adhesive resin layer is a resin of any one of polypropylene, acid-modified polypropylene, low-density polyethylene, and linear low-density polyethylene, the exterior member has a peripheral seal portion and a storage portion formed at a predetermined depth from an inner edge of the peripheral seal portion and for storing the energy storage element, a depth direction of the storage portion and a first direction perpendicular to the depth direction of the storage portion are arranged in the front-to-rear or left-to-right direction of the electric vehicle, and a second direction perpendicular to the depth direction of the storage portion and the first direction is arranged in the height direction of the electric vehicle, and the peripheral seal portion extending in the first direction is overlapped on a peripheral wall of the storage portion by bending.

2. The power storage device according to claim 1 , wherein the length of the storage section in the first direction is greater than the length of the storage section in the second direction.

3. 3. The power storage device according to claim 2, wherein the length of the storage section in the first direction is 2 to 30 times the length of the storage section in the second direction.

4. 4. The power storage device according to claim 1, wherein a flow direction of the exterior member is perpendicular to the first direction.

5. The energy storage device according to any one of claims 1 to 4, characterized in that the energy storage element has a first electrode terminal and a second electrode terminal, and the first electrode terminal and the second electrode terminal protrude from the peripheral seal portion extending in the second direction.

6. The power storage device according to claim 5 , wherein the first electrode terminal protrudes from one of the peripheral seal portions facing each other in the first direction, and the second electrode terminal protrudes from the other peripheral seal portion.

7. 7. An electricity storage device assembly comprising a plurality of electricity storage devices according to any one of claims 1 to 6 arranged side by side in a depth direction of the storage section and housed in an outer container to be mounted on an electric vehicle, the outer container being placed on a metal plate.

8. 7. An electric storage device assembly comprising a plurality of electric storage devices according to any one of claims 1 to 6 arranged side by side in the depth direction of the storage section and stored in an outer container, the electric storage device assembly being mounted on an electric vehicle, characterized in that a length in the direction in which the plurality of electric storage devices are arranged side by side is greater than a length in the second direction.

9. The electricity storage device assembly according to claim 8 , wherein a length in the first direction is greater than a length in a direction in which the plurality of electricity storage devices are arranged side by side.

10. 10. The electricity storage device assembly according to claim 8, further comprising a mounting member on which the outer container is placed, the mounting member having a temperature adjusting function.

11. 10. The electricity storage device assembly according to claim 8, further comprising a mounting member on which the outer container is placed, the mounting member being made of a liquid absorbent material.

12. An electric vehicle comprising: an electricity storage device assembly according to any one of claims 7 to 11; a drive motor supplied with power from the electricity storage device assembly; and wheels driven by the drive motor, the electricity storage device assembly being arranged in a single tier in the height direction at a bottom of a vehicle body.

13. A method for manufacturing an electricity storage device to be mounted as a driving source in an electric vehicle, the method comprising the steps of: preparing an exterior member having a storage section made of a laminate having a base layer, a barrier layer, and a thermal adhesive resin layer; and storing an electricity storage element in the storage section and packaging the storage element with the exterior member; the substrate layer comprises a single-layer or multi-layer resin film of any one of nylon, polyester, and polyethylene terephthalate, the barrier layer comprises a metal foil of any one of aluminum, aluminum alloy, and stainless steel, the thermal adhesive resin layer is a resin of any one of polypropylene, acid-modified polypropylene, low-density polyethylene, and linear low-density polyethylene, a depth direction of the storage section and a first direction perpendicular to the depth direction of the storage section are disposed in a front-rear or left-right direction of the electric vehicle, and a second direction perpendicular to the depth direction of the storage section and the first direction are disposed in a height direction of the electric vehicle, the length of the storage section in the first direction is greater than the length of the storage section in the second direction, and the packaging process with the exterior member includes forming a peripheral seal portion on the periphery of the exterior member that seals the exterior member by thermal bonding of the thermal adhesive resin layer, and folding the peripheral seal portion extending in the first direction to overlap it on a peripheral wall of the storage section.

14. 14. The method for manufacturing an electricity storage device according to claim 13, wherein the length of the storage section in the first direction is 2 to 30 times the length of the storage section in the second direction.

15. The method for manufacturing an electricity storage device according to claim 13 , wherein the first direction is perpendicular to a flow direction of the exterior member.

Images