JP7186802B2 - Battery pack and battery system - Google Patents

Description

Embodiments of the present invention relate to battery packs and battery systems.

Some battery packs include a battery module in which a plurality of batteries (storage batteries) are arranged. In such a battery pack, a frame is formed from an electrically insulating resin, and the battery modules are housed in a housing space surrounded by the frame. The battery pack as described above is used, for example, as a stationary power source, a railroad vehicle power source, and the like. In this case, a large number of battery modules (battery packs) are arranged in a limited space. A battery system (storage battery system) is formed by electrically connecting a large number of battery modules, and in the battery system, at least one of a series connection structure and a parallel connection structure of the battery modules is formed.

In the battery system as described above, charging and discharging may be performed with a large current, and the battery may generate heat due to the charging and discharging with a large current, resulting in a high temperature. Therefore, a battery module in which a plurality of batteries are arranged is required to appropriately dissipate heat generated from the batteries. Also, the battery system as described above is sometimes used at a high working voltage. For this reason, it is required to form an insulating structure having a high withstand voltage (dielectric strength) in the battery pack, and it is required to form an insulating structure that is resistant to dielectric breakdown.

International Publication No. 2013/084938 JP 2013-12464 A

The problem to be solved by the present invention is to provide a battery pack in which an insulation structure with high withstand voltage is formed and heat is appropriately dissipated from the battery module, and a battery system including the battery pack.

According to an embodiment, a battery pack includes battery modules, a frame, and a sheet member. A battery module includes a plurality of arranged batteries, and has a module bottom surface facing one side in a height direction that intersects the arrangement direction of the plurality of batteries. Each of the plurality of batteries includes an electrode group and a metal outer container in which the electrode group is housed. The frame has frame side walls extending in the height direction and is made of electrically insulating resin. A storage space for the battery module is formed by the frame sidewall. The sheet member is made of an electrically insulating resin. The sheet member includes a first layer adhered to the bottom surface of the module, and a second layer laminated on the first layer on the side opposite to the side on which the battery module is positioned in the height direction. The first layer is more thermally conductive and compressible than the frame and second layer. The first layer is compressed at a portion contacting the module bottom surface of the battery module. The sheet member has a sheet upper surface that contacts the module bottom surface of the battery module. The seat top surface is formed from the first layer, and the second layer is not exposed at the seat top surface.

Further, according to an embodiment, a battery system includes the aforementioned battery pack and a cooling plate. The battery pack is installed on the outer surface of the cooling plate, and the cooling plate is provided on the opposite side of the sheet member to the side on which the battery modules are located in the height direction. Heat is transferred from the battery module to the cooling plate through the sheet member.

FIG. 1 is a perspective view schematically showing an example of a single battery used in a battery pack according to a first embodiment. 2 is a schematic diagram showing an example of an electrode group used in the battery of FIG. 1. FIG. FIG. 3 is a schematic diagram showing the battery pack according to the first embodiment. FIG. 4 is a schematic diagram showing the battery pack of FIG. 3 as viewed from one side in the height direction. FIG. 5 is a cross-sectional view schematically showing the battery pack of FIG. 3 in a cross section perpendicular or substantially perpendicular to the battery arrangement direction. FIG. 6 is a cross-sectional view schematically showing the battery pack of FIG. 3 in a cross section perpendicular or substantially perpendicular to the width direction. 7A and 7B are schematic diagrams illustrating an operation of adhering a sheet member to the bottom surface of the battery module in manufacturing the battery pack according to the first embodiment. 8A and 8B are schematic diagrams illustrating the work of adhering the bottom plate to the sheet member in manufacturing the battery pack according to the first embodiment. FIG. 9 is a schematic diagram showing an example of a battery system to which the battery pack according to the first embodiment is applied. FIG. 10 is a schematic diagram showing a battery pack according to a first modified example. FIG. 11 is a schematic diagram showing a sheet member according to a second modified example. FIG. 12 is a schematic diagram showing an example of a battery system to which a battery pack according to the third modification is applied. FIG. 13 is a schematic diagram showing a battery pack according to a fourth modification as viewed from one side in the height direction. 14 is a cross-sectional view schematically showing the battery pack of FIG. 13 in a cross section perpendicular or substantially perpendicular to the longitudinal direction.

Embodiments will be described below with reference to FIGS. 1 to 14. FIG.

A battery pack according to an embodiment includes a battery module. A battery module includes a plurality of batteries. A battery used in the battery module is, for example, a secondary battery such as a non-aqueous electrolyte secondary battery.

[First embodiment]
(battery)
First, the battery used in the battery pack according to the first embodiment will be described. FIG. 1 shows an example of a single battery 1 used in a battery pack. Here, the battery 1 is, for example, a sealed non-aqueous electrolyte secondary battery. A battery 1 includes an electrode group 2 and an outer container 3 in which the electrode group 2 is accommodated. The exterior container 3 is made of metal such as aluminum, aluminum alloy, iron, or stainless steel. The exterior container 3 includes a container body 5 and a lid 6.

Here, in the battery 1 (exterior container 3), the vertical direction (direction indicated by arrows X1 and X2) and the horizontal direction (direction indicated by arrows Y1 and Y2) crossing (perpendicular or substantially perpendicular to) the longitudinal direction ), and a height direction (perpendicular or nearly perpendicular) to both the longitudinal and lateral directions (direction indicated by arrows Z1 and Z2) is defined. In the battery 1 (outer container 3), the dimension in the vertical direction is much smaller than the dimension in the horizontal direction and the dimension in the height direction.

The container body 5 has a bottom wall (container bottom wall) 11 and side walls (container side walls) 12A, 12B, 13A, and 13B. In the container body 5, an internal cavity in which the electrode group 2 is accommodated is formed by the bottom wall 11 and the side walls 12A, 12B, 13A, and 13B. Further, the container main body 5 is formed with an opening 15 through which the internal cavity opens. The internal cavity opens to one side (upper side) in the height direction of the outer container 3 at the opening 15 . In the outer container 3 , the lid 6 closes the opening 15 of the internal cavity. The lid 6 is then welded to the container body 5 at the opening 15 . Therefore, in the outer container 3, the bottom wall 11 is arranged apart from the lid 6 in the height direction across the inner cavity. The lid 6 forms the upper wall (container upper wall) of the exterior container 3 . In the external container 3 , the outer surface of the bottom wall 11 is a bottom surface (container bottom surface) 16 , and the outer surface of the lid 6 is a top surface (container top surface) 17 . In addition, the dimension from the bottom surface 16 to the top surface 17 of the exterior container 3 is the same or substantially the same as the dimension in the height direction of the exterior container 3 .

In the outer container 3, each of the side walls 12A, 12B, 13A, 13B extends from the bottom wall 11 to the lid 6 along the height direction. Sidewalls 12A, 12B are laterally spaced apart from each other across the internal cavity, and sidewalls 13A, 13B are longitudinally spaced apart from each other across the internal cavity. Each of sidewalls 12A and 12B extends vertically from sidewall 13A to sidewall 13B, and each of sidewalls 13A and 13B extends horizontally from sidewall 12A to sidewall 12B. The dimension from the outer surface of the side wall 12A to the outer surface of the side wall 12B in the exterior container 3 is the same or substantially the same as the dimension of the exterior container 3 in the horizontal direction. The dimension from the outer surface of the side wall 13A to the outer surface of the side wall 13B in the exterior container 3 is the same or substantially the same as the dimension of the exterior container 3 in the vertical direction.

FIG. 2 is a diagram showing an example of the electrode group 2. As shown in FIG. In one example of FIG. 2 , the electrode group 2 includes a positive electrode 21 , a negative electrode 22 , and separators 23 and 25 . The positive electrode 21 includes a positive electrode current collector foil 21A as a positive electrode current collector, and a positive electrode active material-containing layer 21B carried on the surface of the positive electrode current collector foil 21A. The positive current collector foil 21A is an aluminum foil, an aluminum alloy foil, or the like, and has a thickness of about 10 μm to 20 μm. A slurry containing a positive electrode active material, a binder, and a conductive agent is applied to the positive current collector foil 21A. Examples of positive electrode active materials include, but are not limited to, oxides, sulfides, and polymers that can intercalate and deintercalate lithium ions. Moreover, from the viewpoint of obtaining a high positive electrode potential, it is preferable that the positive electrode active material is lithium-manganese composite oxide, lithium-nickel composite oxide, lithium-cobalt composite oxide, lithium iron phosphate, or the like.

The negative electrode 22 includes a negative electrode current collector foil 22A as a negative electrode current collector, and a negative electrode active material containing layer 22B carried on the surface of the negative electrode current collector foil 22A. The negative electrode collector foil 22A is an aluminum foil, an aluminum alloy foil, a copper foil, or the like, and has a thickness of about 10 μm to 20 μm. A slurry containing a negative electrode active material, a binder, and a conductive agent is applied to the negative electrode current collector foil 22A. Examples of the negative electrode active material include, but are not limited to, metal oxides, metal sulfides, metal nitrides, and carbon materials that can occlude and release lithium ions. As the negative electrode active material, a material having a lithium ion absorption/discharge potential of 0.4 V or more relative to the metal lithium potential, that is, a lithium ion absorption/discharge potential of 0.4 V (vs. Li ⁺ /Li) or more. It is preferably a substance. By using a negative electrode active material having such a lithium ion absorption/release potential, an alloy reaction between aluminum or an aluminum alloy and lithium is suppressed. Allows the use of aluminum alloys. Examples of the negative electrode active material having a lithium ion absorption/desorption potential of 0.4 V (vs. Li ⁺ /Li) or higher include titanium oxides, lithium-titanium composite oxides such as lithium titanate, tungsten oxides, and amorphous tin. oxides, niobium-titanium composite oxides, tin silicon oxides, silicon oxides, and the like, and it is particularly preferable to use lithium-titanium composite oxides as the negative electrode active material. Note that when a carbon material that absorbs and releases lithium ions is used as the negative electrode active material, a copper foil is preferably used as the negative electrode current collector foil 22A. The carbon material used as the negative electrode active material has a lithium ion absorption/discharge potential of about 0 V (vs. Li ⁺ /Li).

The aluminum alloy used for the positive electrode current collector foil 21A and the negative electrode current collector foil 22A desirably contains one or more elements selected from Mg, Ti, Zn, Mn, Fe, Cu and Si. The purity of aluminum and aluminum alloys can be 98 wt% or higher, preferably 99.99 wt% or higher. Also, pure aluminum with a purity of 100% can be used as a material for the positive electrode current collector and/or the negative electrode current collector. The content of transition metals such as nickel and chromium in aluminum and aluminum alloys is preferably 100 ppm by weight or less (including 0 ppm by weight).

In the positive current collector foil 21A, a positive current collector tab 21D is formed by one long side edge 21C and its vicinity. In this embodiment, the positive electrode current collecting tab 21D is formed over the entire length of the long edge 21C. In the positive electrode current collector tab 21D, the positive electrode active material containing layer 21B is not carried on the surface of the positive electrode current collector foil 21A. Further, in the negative electrode current collector foil 22A, a negative electrode current collector tab 22D is formed by one long side edge 22C and its vicinity. In this embodiment, the negative electrode current collecting tab 22D is formed over the entire length of the long edge 22C. In the negative electrode current collecting tab 22D, the negative electrode active material containing layer 22B is not carried on the surface of the negative electrode current collecting foil 22A.

Each of the separators 23 and 25 is made of an electrically insulating material, and electrically insulates between the positive electrode 21 and the negative electrode 22 . Each of the separators 23 and 25 may be a sheet or the like separate from the positive electrode 21 and the negative electrode 22 , or may be formed integrally with one of the positive electrode 21 and the negative electrode 22 . Also, the separators 23 and 25 may be made of an organic material, an inorganic material, or a mixture of an organic material and an inorganic material. Examples of the organic material forming the separators 23 and 25 include engineering plastics and super engineering plastics. Engineering plastics include polyamide, polyacetal, polybutylene terephthalate, polyethylene terephthalate, syndiotactic polystyrene, polycarbonate, polyamideimide, polyvinyl alcohol, polyvinylidene fluoride and modified polyphenylene ether. Super engineering plastics include polyphenylene sulfide, polyetheretherketone, liquid crystal polymer, polyvinylidene fluoride, polytetrafluoroethylene (PTFE), polyethernitrile, polysulfone, polyacrylate, polyetherimide and thermoplastic polyimide. be done. Inorganic materials forming the separators 23 and 25 include oxides (eg, aluminum oxide, silicon dioxide, magnesium oxide, phosphorous oxide, calcium oxide, iron oxide, titanium oxide), nitrides (eg, boron nitride, aluminum nitride, silicon nitride, barium nitride) and the like.

In the electrode group 2, the positive electrode 21, the negative electrode 22, and the separators 23, 25 are geometrically ( It is wound in a flat shape centering on the winding axis B of (imaginary). At this time, for example, the positive electrode 21, the separator 23, the negative electrode 22, and the separator 25 are wound while being stacked in this order. Further, in the electrode group 2, the positive electrode current collecting tab 21D of the positive electrode current collecting foil 21A protrudes to one side in the direction along the winding axis B with respect to the negative electrode 22 and the separators 23 and 25. As shown in FIG. Then, the negative electrode current collecting tab 22D of the negative electrode current collecting foil 22A protrudes from the positive electrode 21 and the separators 23, 25 in the direction along the winding axis B opposite to the side where the positive electrode current collecting tab 21D projects. do.

The electrode group 2 is arranged in the internal cavity of the outer container 3 with the winding axis B along the horizontal direction of the battery 1 (the outer container 3). Therefore, in the electrode group 2 arranged in the inner cavity of the outer container 3 , the positive electrode current collecting tab 21D protrudes toward the negative electrode 22 in one lateral direction of the battery 1 . In the electrode group 2, the negative electrode current collecting tab 22D protrudes with respect to the positive electrode 21 in the lateral direction of the battery 1 in the opposite direction to the side where the positive electrode current collecting tab 21D projects. In addition, in the internal cavity of the outer container 3, the positive electrode current collecting tab 21D is arranged at one end of the battery 1 in the horizontal direction. In the inner cavity of the outer container 3, the negative electrode current collecting tab 22D is arranged at the end of the battery 1 on the side opposite to the positive electrode current collecting tab 21D in the lateral direction.

Also, the electrode group need not have a wound structure in which the positive electrode, the negative electrode, and the separator are wound. In one embodiment, the electrode group has a stack structure in which a plurality of positive electrodes and a plurality of negative electrodes are alternately stacked, and a separator is provided between the positive electrodes and the negative electrodes. Also in this case, in the electrode group, the positive current collecting tab protrudes to one side in the lateral direction of the battery 1 with respect to the negative electrode. In the electrode group, the negative electrode current collecting tab protrudes with respect to the positive electrode in the lateral direction of the battery 1 in the opposite direction to the side where the positive electrode current collecting tab projects.

Also, in one embodiment, the electrode group 2 is impregnated with an electrolytic solution (not shown) in the inner cavity of the outer container 3 . As the electrolytic solution, a non-aqueous electrolytic solution is used, and for example, a non-aqueous electrolytic solution prepared by dissolving an electrolyte in an organic solvent is used. In this case, as the electrolyte dissolved in the organic solvent, lithium perchlorate (LiClO ₄ ), lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), lithium arsenic hexafluoride (LiAsF ₆ ), lithium salts such as lithium trifluoromethanesulfonate (LiCF ₃ SO ₃ ) and lithium bistrifluoromethylsulfonylimide [LiN(CF ₃ SO ₂ ) ₂ ], and mixtures thereof. In addition, as an organic solvent, cyclic carbonates such as propylene carbonate (PC), ethylene carbonate (EC) and vinylene carbonate; chain carbonates such as diethyl carbonate (DEC), dimethyl carbonate (DMC) and methyl ethyl carbonate (MEC); tetrahydrofuran cyclic ethers such as (THF), 2-methyltetrahydrofuran (2MeTHF), and dioxolane (DOX); linear ethers such as dimethoxyethane (DME) and diethoxyethane (DEE); γ-butyrolactone (GBL), acetonitrile (AN) and sulfolane (SL). These organic solvents are used alone or as a mixed solvent.

In one embodiment, a non-aqueous gel electrolyte obtained by combining a non-aqueous electrolyte and a polymer material is used instead of the electrolyte. In this case, the electrolyte and organic solvent described above are used. Polymer materials include polyvinylidene fluoride (PVdF), polyacrylonitrile (PAN), and polyethylene oxide (PEO).

Also, in some embodiments, solid electrolytes such as polymer solid electrolytes and inorganic solid electrolytes are provided as non-aqueous electrolytes instead of electrolyte solutions. In this case, the electrode group 2 may not be provided with a separator. In the electrode group 2, instead of the separator, a solid electrolyte is sandwiched between the positive electrode and the negative electrode. Therefore, in this embodiment, the positive electrode and the negative electrode are electrically insulated by the solid electrolyte.

In the battery 1, a pair of electrode terminals 26A and 26B are attached to the outer surface (upper surface 17) of the lid 6 of the outer container 3. As shown in FIG. The electrode terminals 26A, 26B are made of a conductive material such as metal. One of the electrode terminals 26A and 26B is a positive terminal, and the other of the electrode terminals 26A and 26B is a negative terminal. Therefore, the electrode terminals 26A, 26B have opposite electrical polarities with respect to each other. Each of the electrode terminals 26A, 26B is electrically insulated from the exterior container 3 including the lid 6 by an insulating member (not shown).

The positive current collecting tab 21D of the electrode group 2 is electrically connected to a positive terminal (corresponding one of the electrode terminals 26A and 26B) via a positive backup lead 27A and a positive lead 28A. Also, the negative current collecting tab 22D of the electrode group 2 is electrically connected to a negative terminal (one of the electrode terminals 26A and 26B) via a negative backup lead 27B and a negative lead 28B. Each of backup leads 27A, 27B and leads 28A, 28B is formed from a conductive material such as metal. In addition, in the internal cavity of the exterior container 3, the current collecting tabs 21D and 22D, the backup leads 27A and 27B, and the leads 28A and 28B are each connected by insulating members (not shown) to the exterior container 3 (container body 5 and lid). 6) is electrically isolated.

Also, each of the electrode terminals 26A and 26B has a contact surface 29 . In the example of FIG. 1, the contact surface 29 of each of the electrode terminals 26A and 26B faces the side (upper side) where the upper surface 17 faces in the height direction. The battery 1 has a dimension (standard dimension) L in the height direction from the bottom surface (container bottom surface) 16 of the outer container 3 to the contact surfaces 29 of the electrode terminals 26A and 26B.

Also, in one embodiment, the lid 6 may be formed with a gas release valve and a liquid inlet (both not shown). When the liquid inlet is formed in the lid 6 , a sealing plate (not shown) that closes the liquid inlet is welded to the outer surface (upper surface 17 ) of the lid 6 .

(Battery pack and battery system)
3 to 6 show the battery pack 30. FIG. As shown in FIGS. 3 to 6 , the battery pack 30 includes battery modules 31 . The battery module 31 includes a plurality of the batteries 1 described above, and the battery module 31 includes six batteries 1 in the example shown in FIGS. In the battery module 31, a plurality of batteries 1 are arranged along the arrangement direction (the directions indicated by arrows X3 and X4).

Here, in the battery pack 30 and the battery module 31, the arrangement direction of the batteries coincides or substantially coincides with the vertical direction. In addition, in the battery pack 30 and the battery module 31, a height direction (a direction indicated by an arrow Z3 and an arrow Z4) that intersects (perpendicular or approximately perpendicular) to the arrangement direction of the batteries 1 in the battery module 31 is defined. be. In the battery module 31 (battery pack 30), the width direction (the direction indicated by the arrow Y3 and the arrow Y4) that intersects (perpendicular or substantially perpendicular to) both the height direction and the arrangement direction of the batteries 1 is specified. be done. FIG. 3 is a perspective view schematically showing battery pack 30, and FIG. 4 schematically shows battery pack 30 viewed from one side in the height direction (arrow Z3 side). 5 schematically shows the battery pack 30 in a cross section perpendicular or substantially perpendicular to the arrangement direction of the batteries 1, and FIG. 6 schematically shows the battery pack 30 in a cross section perpendicular or substantially perpendicular to the width direction. shown in

3 to 6, the vertical direction of each battery 1 coincides or substantially coincides with the arrangement direction of the batteries 1, and the horizontal direction of each battery 1 coincides with the battery module 31 (battery pack 30). ) match or substantially match the width direction. In the battery module 31, the height direction of each battery 1 matches or substantially matches the height direction of the battery module 31 (battery pack 30). Also, in the battery module 31 , the plurality of batteries 1 are arranged in the width direction of the battery module 31 (lateral direction of each battery 1 ) with no or almost no displacement with respect to each other.

In addition, the battery module 31 includes a module bottom surface 32 facing one side (lower side) in the height direction, and a module top surface 33 facing the side (upper side) opposite to the side to which the module bottom surface 32 faces in the height direction. . In each of the plurality of batteries 1 (all the batteries 1), the bottom surface 16 of the outer container 3 is located on the side where the module bottom surface 32 is located with respect to the electrode group 2 in the height direction. The bottom surface 16 of the outer container 3 of each of the batteries 1 forms part of the module bottom surface 32 . In addition, in each of the plurality of batteries 1 (all the batteries 1), the upper surface 17 of the outer container 3 and the electrode terminals 26A and 26B are located on the side where the module upper surface 33 is located with respect to the electrode group 2 in the height direction. To position. The upper surface 17 and the electrode terminals 26A and 26B of the outer container 3 of each of the plurality of batteries 1 form part of the upper surface 33 of the module.

In the battery module 31, partition plates (separators) 36 are provided between the batteries 1 that are adjacent to each other in the arrangement direction. One or more partition plates 36 are provided, and five partition plates 36 are provided in the example of FIGS. 3 to 6 . Each partition plate 36 forms part of the module bottom surface 32 and forms part of the module top surface 33 .

The partition plate 36 is made of an electrically insulating material. The partition plate 36 is made of, for example, an electrically insulating resin, and includes one or more of polyphenylene ether (PPE), polycarbonate (PC), and polybutylene terephthalate (PBT). Moreover, the thermal conductivity of the partition plate 36 is less than 1 W/(m·K), for example, the thermal conductivity of the partition plate 36 is approximately 0.2 W/(m·K). In the battery module 31 , the partition plate 36 prevents adjacent batteries 1 from coming into contact with each other. Therefore, for example, it is effectively prevented that the batteries 1 adjacent to each other are electrically connected to each other through the outer container 3 . That is, it is effectively prevented that the batteries 1 adjacent to each other are electrically connected without interposing the electrode terminals 26A and 26B.

It should be noted that the entire partition plate 36 does not have to be made of the electrically insulating material described above, and at least the outer surface of the partition plate 36 may be made of the electrically insulating material described above. In one embodiment, the partition plate 36 is formed by forming an insulating layer from the aforementioned electrically insulating material on the outer surface of a metal plate. Also in this case, at least the outer surface of the partition plate 36 is made of the above-described electrically insulating material. By using a metal plate inside the partition plate 36 , the heat generated in each battery 1 can be easily transferred to the module bottom surface 32 through the partition plate 36 .

The battery module 31 also includes an adhesive 37 that adheres each of the batteries 1 to the partition plate 36 . As the adhesive 37, a silicone-based or epoxy-based adhesive is preferably used. These adhesives maintain elasticity even in the temperature range in which battery pack 30 is used. Therefore, by using a silicone-based or epoxy-based adhesive as the adhesive 37, the adhesive 37 absorbs the impact from the outside and also absorbs the strain caused by the expansion of the battery 1. . In addition, silicone-based and epoxy-based adhesives have a thermal conductivity of 1 W/(m·K) or more. Therefore, by using these adhesives as the adhesive 37 , the heat generated in each battery 1 can be easily transferred to the partition plate 36 through the adhesive 37 . As previously mentioned, the divider plate 36 forms part of the module bottom surface 32 . Therefore, by using the aforementioned adhesive with high thermal conductivity as the adhesive 37, the heat generated in each battery 1 can be released through the partition plate 36 to the side where the module bottom surface 32 is located.

It should be noted that in some embodiments, instead of the adhesive 37, grease or the like having a higher thermal conductivity than the above-described adhesive may be used. As a result, the heat generated in each battery 1 can be more appropriately released through the partition plate 36 to the side where the module bottom surface 32 is located. Also, in some other embodiments, no adhesive 37 or the like is provided, and each battery 1 may directly abut the corresponding partition plate 36 .

The battery pack 30 also includes a busbar (connection member) 38 , and in this embodiment, the battery pack 30 is provided with a plurality of busbars 38 . Bus bar 38 is formed from a conductive material such as metal. In battery module 31 , each of batteries 1 is electrically connected to other batteries 1 via busbar 38 . Battery modules 31 are also electrically connected to external terminals of battery pack 30 via bus bars. In the battery module 31 , at least one of a series connection structure and a parallel connection structure of the batteries 1 is formed by electrically connecting the plurality of batteries 1 with the bus bars 38 . In each of the plurality of batteries 1, the busbar 38 is in contact with the contact surface 29 and the busbar 38 is connected to the contact surface 29 in each of the electrode terminals 26A and 26B. In addition, in each of the electrode terminals 26A and 26B, the bus bar 38 is connected (fixed) to the contact surface 29 by welding, screwing, fitting, or the like.

Here, in the series connection structure of the two batteries 1 , the positive terminal of one battery 1 is connected to the negative terminal of the other battery 1 by the bus bar 38 . Moreover, in the parallel connection structure of a plurality of batteries 1 , the positive terminals of the batteries 1 are connected to each other by the busbar 38 , and the negative terminals of the batteries 1 are connected to each other by another busbar 38 .

Battery pack 30 includes frame 40 . The frame 40 is made of electrically insulating resin. The frame 40 can be made of the same material as the partition plate 36 (the outer surface of the partition plate 36), for example. Frame 40 includes, for example, one or more of polyphenylene ether, polycarbonate, and polybutylene terephthalate. The thermal conductivity of the frame 40 is less than 1 W/(m·K), for example, the thermal conductivity of the frame 40 is approximately 0.2 W/(m·K).

Frame 40 includes frame side walls 41A, 41B, 42A, and 42B extending along the height direction of battery pack 30 . The frame side wall 41A faces the battery module 31 from one side (arrow X3 side) in the arrangement direction of the batteries 1 (vertical direction of the battery pack 30). In addition, the frame side wall 41B faces the battery module 31 from the opposite side (arrow X4 side) of the frame side wall 41A in the arrangement direction of the batteries 1 . Frame side wall 42A faces battery module 31 from one side (arrow Y3 side) in the width direction of battery module 31 (battery pack 30). In addition, the frame side wall 42B faces the battery module 31 from the opposite side (arrow Y4 side) of the frame side wall 42A in the width direction of the battery module 31 . Therefore, the battery module 31 is arranged between the frame side walls 41A and 41B in the vertical direction of the battery pack 30, and between the frame side walls 42A and 42B in the width direction of the battery pack 30. As shown in FIG.

Due to the configuration as described above, the frame side walls 41A, 41B, 42A, and 42B form an enclosing frame that surrounds the outer peripheral side of the battery module 31 over the entire circumference of the battery module 31 . Frame side walls 41A, 41B, 42A, and 42B form storage space 43 in which battery module 31 is stored. That is, the storage space 43 is a range surrounded by the surrounding frame formed by the frame side walls 41A, 41B, 42A, and 42B. The battery module 31 is fixed to the inner surface of the enclosure with an adhesive (not shown) or the like.

In battery pack 30 , sheet member 45 contacts module bottom surface 32 of battery module 31 . The sheet member 45 is made of an electrically insulating resin. The sheet member 45 contacts the module bottom surface 32 from the side facing the module bottom surface 32 in the height direction of the battery pack 30 . The outer surface of sheet member 45 includes a sheet top surface 46 that abuts module bottom surface 32 . In addition, the outer surface of sheet member 45 includes sheet bottom surface 47 that faces the side opposite to the side on which battery module 31 is positioned in the height direction of battery pack 30 . The seat bottom surface 47 faces the side opposite to the side to which the seat upper surface 46 faces.

In the battery pack 30 of the present embodiment, the bottom plate (supporting member) 48 is attached to the frame 40 from the side facing the module bottom surface 32 in the height direction of the battery pack 30 . The bottom plate 48 is made of metal, such as aluminum, an aluminum alloy, stainless steel, copper, or the like. Therefore, the bottom plate 48 has higher thermal conductivity than the partition plate 36, the frame 40, and the sheet member 45. The thermal conductivity of the bottom plate 48 is, for example, 10 W/(m·K) or more and 400 W/(m·K) or more. K) or less. In the present embodiment, each of the frame side walls 41A, 41B, 42A, 42B extends from the bottom plate 48 along the height direction of the battery pack 30 toward the module upper surface 33 (arrow Z3 side).

Also, the bottom plate 48 abuts on the sheet bottom surface 47 of the sheet member 45 from the side opposite to the side where the battery modules 31 are located in the height direction of the battery pack 30 . Therefore, sheet member 45 is sandwiched between battery module 31 and bottom plate 48 in the height direction of battery pack 30 . The bottom plate 48 is formed in a flat plate shape or a substantially flat plate shape with a thickness of about 0.5 mm or more and 5 mm or less. A contact surface of the bottom plate 48 that contacts the sheet member 45 is formed in a flat or substantially flat shape. It should be noted that the bottom plate 48 is formed in appropriate dimensions, shape, etc., as required. Also, the sheet member 45 is arranged in a range surrounded by a surrounding frame formed by the frame side walls 41A, 41B, 42A and 42B. Therefore, in this embodiment, the sheet member 45 is not provided between each of the frame side walls 41A, 41B, 42A, 42B and the bottom plate 48, and one end of each of the frame side walls 41A, 41B, 42A, 42B (bottom plate 48 is located) abuts on the bottom plate 48 .

By providing the sheet member 45 and the bottom plate (support member) 48 as described above, the bottom plate 48 supports the battery modules 31 and the sheet member 45 from the side facing the module bottom surface 32 in the height direction of the battery pack 30. . Heat generated in the battery module 31 is transferred to the bottom plate 48 via the sheet member 45 .

Also, in this embodiment, the sheet member 45 comprises three layers 51-53. Layer (first layer) 51 adheres to module bottom surface 32 of battery module 31 . Layer (second layer) 52 is stacked on layer 51 on the side opposite to the side where battery module 31 is located in the height direction of battery pack 30 . Layer (third layer) 53 is laminated on layer 52 on the side opposite to the side on which layer 51 is laminated in the height direction of battery pack 30 (the lamination direction of sheet member 45). Layer 53 then adheres to bottom plate 48 . In this embodiment, the layer 51 forms the seat top surface 46 and the layer 53 forms the seat bottom surface 47 .

Each of the layers 51 and 53 has stickiness, and the stickiness is higher than that of the layer 52 . Each of layers 51 and 53 includes, for example, silicone. Layer 52 includes at least one of polyethylene terephthalate (PET), polyimide (PI), polypropylene (PP), and polybutylene terephthalate (PBT). Note that the layer 53 has the same level of adhesiveness as the layer 51 or has lower adhesiveness than the layer 51 . When layers 51 and 53 each contain silicone, the tackiness of each of layers 51 and 53 will be dimensioned based on the macromolecular polymer combination, crosslink density and purity of the silicone, and the like. Since each of the layers 51 and 53 has adhesiveness, the adhesion of the sheet member 45 to the module bottom surface 32 and the bottom plate 48 is ensured even when the position of the sheet member 45 is displaced due to vibration, heat, or the like.

Also, each of the layers 51 and 53 has higher thermal conductivity than the partition plate 36 , the frame 40 and the layer 52 . However, each of layers 51 and 53 has a lower thermal conductivity than outer container 3 and bottom plate 48 of battery 1 . The thermal conductivity of the layers 51 and 53 is 1 W/(m·K) or more, for example, the thermal conductivity of each of the layers 51 and 53 is 1 W/(m·K) or more and 10 W/(m·K) or less. degree. Note that the layer 52 has thermal conductivity comparable to that of the partition plate 36 and the frame 40 . Therefore, the thermal conductivity of layer 52 is less than 1 W/(m·K), for example, on the order of 0.2 W/(m·K).

Also, layer 52 is thinner than layers 51 and 53, respectively. And each of the layers 51, 53 is thinner than each of the frame sidewalls 41A, 41B, 42A, 42B. In one embodiment, the layer (second layer) 52 has a layer thickness of 200 μm or less, for example, about 100 μm.

In addition, the layer 52 has higher mechanical strength than the layers 51 and 53 and is less likely to be destroyed by the action of external force than the layers 51 and 53 . Therefore, layer 52 has a higher pressure resistance than layers 51 and 53 . Each of the layers 51 and 53 has higher compressibility than the layer 52 and is more easily compressed by the action of an external force than the layer 52 . Therefore, each of layers 51 and 53 has a higher elasticity than layer 52 . It should be noted that layer 53 may be as compressible as layer 51 or may be less compressible than layer 51 .

Here, the layer 51 is formed so soft that the value measured with an Asker-C hardness tester is 30 or less. The Asker-C hardness tester is one of the spring-type hardness testers stipulated in SRIS0101 (Japan Rubber Society Standard). Also, the layer 52 does not compress, or hardly compresses, under the action of an external force.

As described above, each of the plurality of batteries 1 forming the battery module 31 has a height dimension (standard dimension) L. It is preferable that the dimension L of each of the plurality of batteries 1 (all the batteries 1) of the battery module 31 is the same or substantially the same as that of the other batteries 1 . However, the dimension L tends to vary from battery 1 to battery 1 due to manufacturing tolerances of the battery 1 . Actually, in the battery module 31, the dimension L varies from battery 1 to battery 1 within a range of about 0.05 mm or more and 0.2 mm or less. In one example of FIGS. 3 to 6, in battery 1A, which is one of the plurality of batteries 1, the dimension L is the value La, whereas in battery 1B, which is another one of the plurality of batteries 1, the dimension L becomes a value Lb that is greater than the value La.

In the battery module 31 of the present embodiment, the positions of the contact surfaces 29 of the electrode terminals 26A and 26B in the height direction are shifted for each battery 1 from the viewpoint of facilitating connection between the batteries 1 by the busbars 38. or almost no deviation. That is, in each of the plurality of batteries 1 , the positions of the contact surfaces 29 of the electrode terminals 26 A and 26 B in the height direction match or substantially match those of the other batteries 1 . In one example, in each of the plurality of batteries 1, the positions of the contact surfaces 29 of the electrode terminals 26A and 26B in the height direction match the other batteries 1 or are deviated from the other batteries 1. is small (for example, in the range of 1 mm or less). Therefore, as described above, the dimension (reference dimension) L varies from battery to battery 1 , and in the battery module 31 , the position of the bottom surface 16 of the outer container 3 in the height direction is shifted from battery to battery 1 .

As described above, the layer (second layer) 52 of the sheet member 45 is not compressed or hardly compressed by the action of external force. Therefore, even when sandwiched between the battery module 31 and the bottom plate (supporting member) 48, the layer 52 is not compressed, or hardly compressed. Also, in the sheet member 45 , the layer (third layer) 53 is compressed at the site where the bottom plate 48 abuts. Here, the contact surface of the bottom plate 48 with the sheet member 45 is formed flat or substantially flat as described above. Therefore, the amount of compression of the layer 53 is uniform or substantially uniform over the entire layer 53 .

Also, in the sheet member 45 of the battery pack 30 , the layer (first layer) 51 is compressed at the portion where the module bottom surface 32 of the battery module 31 abuts. The same number of container receiving portions 56 as the number of batteries 1 included in the battery module 31 are formed in the layer 51 . A corresponding one of the plurality of batteries 1 abuts against each of the container receiving portions 56 at the bottom surface (container bottom surface) 16 of the outer container 3 . Since one corresponding one of the plurality of batteries 1 abuts on each of the container receiving portions 56, the layer 51 is compressed by the compression amount ε.

Here, the amount of compression ε of the layer 51 at each of the container receiving portions 56 is based on the aforementioned dimension (reference dimension) L of the battery (the corresponding one of 1) in contact with the container receiving portion 56. become. That is, the amount of compression ε in each of the container receiving portions 56 is about the height direction from the bottom surface 16 of the outer container 3 to the contact surface 29 of each of the electrode terminals 26A and 26B in the corresponding one of the plurality of batteries 1. It is sized according to the dimension L. 3 to 6, as described above, the value Lb of the dimension L of the battery 1B is larger than the value La of the dimension L of the battery 1A. In this case, the value εb of the compression amount ε at the container receiving portion 56B with which the battery 1B abuts is larger than the value εa of the compression amount ε at the container receiving portion 56A with which the battery 1A abuts. That is, among the container receiving portions 56, the compression amount ε of the container receiving portion 56 having a larger value of the dimension L of the contacting battery (one corresponding to 1) has a larger value.

Further, among the container receiving portions 56, the layer thickness T of the layer 51 becomes thinner as the container receiving portion 56 has a larger value of the compression amount ε. 3 to 6, as described above, the value of the compression amount ε at the container receiving portion 56B with which the battery 1B abuts is higher than the value εa of the compression amount ε at the container receiving portion 56A with which the battery 1A abuts. εb is large. Therefore, the value Tb of the layer thickness T of the layer 51 at the container receiving portion 56B is smaller than the value Ta of the layer thickness T of the layer 51 at the container receiving portion 56A.

Due to the configuration as described above, in each of the plurality of batteries 1 of the battery module 31, the height of the battery pack 30 from the boundary between the layers 51 and 52 of the sheet member 45 to the contact surface 29 of each of the electrode terminals 26A and 26B is The distance in the vertical direction becomes the same or substantially the same for the other batteries 1 . In each of the plurality of batteries 1 (all the batteries 1), the distance H in the height direction from the sheet bottom surface 47 of the sheet member 45 to the contact surface 29 of each of the electrode terminals 26A and 26B is different from that of the other batteries. are identical or substantially identical to each other. In one example, in each of the plurality of batteries 1, the distance H in the height direction from the sheet bottom surface 47 of the sheet member 45 to the contact surface 29 of each of the electrode terminals 26A and 26B is the same for the other batteries 1. or the difference with respect to other batteries 1 is slight (for example, in the range of 1 mm or less).

As described above, in the present embodiment, even if the dimension (reference dimension) L varies for each battery 1 , the amount of compression ε in each of the container receiving portions 56 is the size based on the corresponding one dimension L of the battery 1 . become. Therefore, variations in the dimension L of each battery 1 are mitigated (absorbed) by the amount of compression ε of the container receiving portion 56 .

Next, a method for manufacturing the battery pack 30 will be described. In manufacturing the battery pack 30, first, a plurality of batteries 1 constituting the battery module 31 are formed. At this time, due to manufacturing tolerances of the battery 1, the dimension (standard dimension) L in the height direction from the bottom surface (container bottom surface) 16 of the outer container 3 to the contact surface 29 of each of the electrode terminals 26A and 26B is different from the battery 1. It may vary from time to time.

Then, a plurality of formed batteries 1 are arranged, and a partition plate 36 is arranged between the batteries 1 adjacent to each other in the arrangement direction of the batteries 1 . Then, each battery 1 is attached to the partition plate 36 with an adhesive 37 . Thereby, the battery module 31 is formed. At this time, in each of the plurality of batteries 1, the positions of the contact surfaces 29 of the electrode terminals 26A and 26B in the height direction are made to match or substantially match those of the other batteries 1. As shown in FIG. Therefore, when the dimension (reference dimension) L varies from battery 1 to battery 1 as described above, the position of the bottom surface 16 of the outer container 3 in the height direction varies from battery 1 to battery module 31 manufactured.

Then, the bus bar 38 is attached to the manufactured battery module 31 . At this time, in each of the plurality of batteries 1, the bus bar 38 is brought into contact with the contact surface 29 of each of the electrode terminals 26A and 26B. Then, in each of the plurality of batteries 1, the bus bar 38 is connected (fixed) to the contact surface 29 of each of the electrode terminals 26A and 26B by welding, screwing, fitting, or the like.

Then, as shown in FIG. 7, the work of adhering the sheet member 45 to the module bottom surface 32 of the battery module 31 is performed. At this time, the battery module 31 is arranged with the module bottom surface 32 facing vertically upward and the module top surface 33 facing vertically downward. Also, the sheet member 45 is arranged in a state in which the sheet upper surface 46 and the layer (first layer) 51 face the module bottom surface 32 . Then, using a jig or the like, the sheet member 45 is pressed against the module bottom surface 32 from the vertical upper side (arrow F1). Then, a press machine is used to apply a predetermined pressure to the battery module 31 via the sheet member 45 . As a result, the layer 51 of the sheet member 45 adheres (adheres) to the module bottom surface 32 of the battery module 31 . At this time, a load of several kg or more acts on each of the plurality of batteries 1 of the battery module 31 . By applying a predetermined pressure to the battery module 31 from the press machine, the portion of the layer 51 with which the module bottom surface 32 of the battery module 31 abuts is compressed. At this time, the layer 52 is not or hardly compressed.

In addition, the portion of the layer 51 that is compressed includes a container receiving portion 56 . By applying a predetermined pressure to the battery module 31 from the press, in each of the container receiving portions 56 , the layer 51 is compressed by the compression amount ε due to the pressure from the corresponding one of the plurality of batteries 1 . The amount of compression ε in each of the container receiving portions 56 is about the height direction from the bottom surface 16 of the outer container 3 to the contact surface 29 of each of the electrode terminals 26A and 26B in the corresponding one of the plurality of batteries 1. It is sized according to the dimension L. Since each of the container receiving portions 56 is compressed as described above, by adhering (adhering) the sheet member 45 to the module bottom surface 32 , the electrode terminals 26 A are removed from the sheet bottom surface 47 of the sheet member 45 in each of the plurality of batteries 1 . , 26B in the height direction to the contact surface 29 are the same or substantially the same for the other batteries. That is, the variation in the dimension L of each battery 1 is mitigated (absorbed) by the compression amount ε of the container receiving portion 56 .

The layer 51 of the sheet member 45 is brought into close contact with the battery module 31 as described above by applying a predetermined pressure to the battery module 31 from the press. Therefore, once the layer 51 of the sheet member 45 is compressed by a press during manufacturing, the layer 51 is maintained in the compressed shape (deformed shape). Therefore, in the manufactured battery pack 30, it is not necessary to apply the same or substantially the same pressure to the sheet member 45 and the battery module 31 as the predetermined pressure applied by the press. As a result, it becomes possible to use a low-rigidity material for the bottom plate 48 and the frame 40, so that the weight of the bottom plate 48 and the frame 40 can be reduced.

Then, as shown in FIG. 8, the work of adhering the bottom plate (supporting member) 48 to the sheet member 45 is performed. At this time, the battery module 31 and the sheet member 45 are arranged with the module bottom surface 32 and the sheet bottom surface 47 facing vertically upward. Then, the bottom plate 48 is vertically pressed against the seat bottom surface 47 (arrow F2). Layer (third layer) 53 is compressed by pressure from bottom plate 48 . At this time, since the contact surface of the bottom plate 48 with the sheet member 45 is formed flat or substantially flat, the amount of compression of the layer 53 is uniform or substantially uniform over the entire layer 53 . Also, the layer 52 is not or hardly compressed by the pressure from the bottom plate 48 .

Then, the frame 40 is attached to the bottom plate 48 , and the battery module 31 is stored in the storage space 43 defined by the frame 40 . The frame 40 is attached to the bottom plate 48 by either bolts, snap-fit structures, or the like. In some embodiments, the bottom plate 48 may be adhered to the sheet member 45 after the frame 40 is attached to the bottom plate 48 . In another embodiment, the frame 40 may be integrally formed with the bottom plate 48 by insert molding. In this case, after integrally forming the frame 40 and the bottom plate 48 , the bottom plate 48 is adhered to the sheet member 45 .

Next, application examples of the battery pack 30 will be described. The battery pack 30 is used, for example, as a stationary power source, a railroad vehicle power source, and the like. In this case, a large number of battery packs 30 mounted with battery modules 31 are provided, and the large number of battery packs 30 form a battery system. In a battery system, a large number of battery modules are electrically connected to form at least one of a series connection structure and a parallel connection structure of the battery modules.

FIG. 9 shows one application of the battery pack 30 . As shown in FIG. 9 , in the battery system 50 and the like described above, the battery pack 30 is installed on the outer surface of the cooling plate (cooling fin) 60 . A large number of battery packs 30 are installed on the outer surface of the cooling plate 60 . The cooling plate 60 is made of metal or the like, and has higher thermal conductivity than the frame 40 , partition plate 36 and sheet member 45 . The thermal conductivity of the cooling plate 60 is, for example, about 10 W/(m·K) to 400 W/(m·K). Battery pack 30 is installed on cooling plate 60 by attaching frame 40 or bottom plate 48 to cooling plate 60 with bolts or the like.

In one example of FIG. 9, the bottom plate 48 abuts the cooling plate 60 . Therefore, the battery module 31 is positioned on the opposite side of the sheet member 45 to the side on which the cooling plate 60 is positioned. That is, cooling plate 60 is provided on the opposite side of sheet member 45 to the side on which battery modules 31 are positioned in the height direction of battery pack 30 . A channel is formed inside the cooling plate 60 . A cooling fluid including a cooling liquid, a cooling gas, and the like flows through the channels of the cooling plate 60 .

In the battery system 50 in which a large number of battery modules are electrically connected as described above, charging and discharging may be performed with a large current. In this case, the battery module 31 of the battery pack 30 may become hot due to charging and discharging with a large current. In this embodiment, the sheet upper surface 46 (layer 51 ) of the sheet member 45 adheres and adheres to the module bottom surface 32 of the battery module 31 . Then, the sheet bottom surface 47 (layer 53 ) of the sheet member 45 is brought into close contact (adhesion) and contact with the bottom plate 48 . Therefore, heat generated in the battery module 31 is transferred to the cooling plate 60 via the sheet member 45 and the bottom plate 48 .

Here, the layers 51 and 53 of the sheet member 45 have higher thermal conductivity than the frame 40 and partition plate 36 . In fact, the layers 51 and 53 have about ten times the thermal conductivity of the frame 40 and the partition plate 36 . In the sheet member 45 , each of the layers 51 and 53 is thicker than the layer 52 . Therefore, the heat from the battery module 31 is properly transferred to the bottom plate 48 and the cooling plate 60 through the sheet member 45 . Therefore, in battery pack 30 , heat is appropriately radiated from battery modules 31 to cooling plate 60 .

Also, the battery system 50 as described above may be used at a high working voltage. For example, depending on the battery system 50, a short-circuit voltage of 1000 V or more may occur in the battery pack 30 when a short circuit occurs. In the battery pack 30 of this embodiment, the frame 40 surrounding the battery modules 31 is made of a material with high electrical insulation. The sheet member 45 that is in close contact with the module bottom surface 32 is also made of a material with high electrical insulation. Therefore, in the battery pack 30, an insulating structure with high withstand voltage (dielectric strength) is appropriately formed.

In addition, the layer 52 of the sheet member 45 is made of a material with high electrical insulation and high mechanical strength. Therefore, even if the layers 51 and 53 are damaged by an external force, the battery module (battery set) 31 is properly electrically insulated from the bottom plate 48 and the cooling plate 60 by the layer 52 . Therefore, even if layers 51 and 53 are damaged by an external force, in battery pack 30 , layer 52 appropriately maintains an insulating structure with high withstand voltage (dielectric strength).

As described above, in the battery pack 30 of the present embodiment, an insulation structure with high withstand voltage is formed, and heat is appropriately radiated from the battery modules 31 .

[Modification]
In the first modification shown in FIG. 10, the sheet member 45 includes a layer (fourth layer) 54 in addition to the layers 51-53. The layer 54 is stacked on the opposite side of the layer 53 to the side on which the layers 51 and 52 are stacked in the height direction (stacking direction) of the battery pack 30 . In this modification, the layer 54 forms the seat bottom surface 47 . The bottom plate 48 then abuts the layer 54 at the seat bottom surface 47 .

Layer 54 will have thermal conductivity and cohesiveness, respectively, comparable to layer 52 . Thus, layer 53 has a higher adhesiveness than layers 52 and 54, respectively, and a higher thermal conductivity than layers 52 and 54, respectively. Layer 54 includes any one or more of polyethylene terephthalate (PET), polyimide (PI), polypropylene (PP), and polybutylene terephthalate (PBT). In one example, layer 54 is formed from the same material as layer 52 .

Also, layer 54, like layer 52, is less compressible than layers 51,53. In fact, layer 54 does not compress, or hardly compresses, under the action of external forces. Also, like the layer 52 , the layer 54 has higher mechanical strength (pressure resistance) than the layers 51 and 53 . Therefore, the layer 54 is less likely to be destroyed by the action of an external force than the layers 51 and 53 . Also, layer 54 is thinner than layers 51 and 53, respectively. In one example, the thickness of the layer (fourth layer) 54 is 200 μm or less, for example, about 100 μm.

Although 54 is provided along the sheet member 45 in this modification, the layer thickness of the layer 54 is thinner than each of the layers 51 and 53 . Therefore, also in this modification, the heat from the battery module 31 is properly transferred to the bottom plate 48 and the cooling plate 60 through the sheet member 45 .

Layer 54 is also less sticky than layers 51 and 53 . In this modified example, a sheet bottom surface 47, which is part of the outer surface of the sheet member 45, is formed from the layer 54 with low adhesiveness. Therefore, the sheet member 45 is less likely to stick to the operator's hand or the like during manufacturing of the battery pack 30 or the like. As a result, workability and the like in assembling the battery pack 30 are improved.

It should be noted that, in a modification, the layer 54 of the sheet member 45 may be adhered to the bottom plate 48 via an adhesive or the like. In this case, the adhesion layer of the adhesive is formed thin. For example, the adhesion layer of adhesive is formed thinner than each of layers 51 and 53 .

Also in the second modification shown in FIG. 11, the sheet member 45 is provided with layers 51 to 54 . However, in this modification, the layer 54 can be peeled off from the layer 53 (arrow F3). In the battery pack 30 , the sheet member 45 adheres (adheres) to the module bottom surface 32 of the battery module 31 with the layer 54 separated from the layer 53 . Therefore, in this variation, layer 54 should not be a component of battery pack 30 . The battery pack 30 has the same configuration as in the first embodiment.

In addition, in the present modification, when the battery pack 30 is manufactured, the sheet upper surface 46 (layer 51) of the sheet member 45 is adhered (adhered) to the module bottom surface 32 of the battery module 31, and the layer 54 is removed from the layer 53. exfoliate. Then, with the layer 54 separated from the layer 53 , the bottom plate 48 is adhered (adhered) to the layer 53 of the sheet member 45 .

Further, in a modification, the sheet member 45 may not have the layer 53 and the sheet member 45 may have a two-layer structure of the layers 51 and 52 . In this case, in this modified example, the sheet bottom surface 47 is formed by the layer (second layer) 52 . The bottom plate 48 then abuts the layer 52 at the seat bottom surface 47 .

Also in this modification, the sheet member 45 is provided with the layer 52 . Therefore, even if the layer 51 is damaged by an external force, the battery module (battery set) 31 is properly electrically insulated from the bottom plate 48 and the cooling plate 60 by the layer 52 . Therefore, even if layer 51 is damaged by an external force, in battery pack 30 , layer 52 appropriately forms an insulating structure with high voltage resistance (dielectric strength).

Moreover, in the third modification shown in FIG. 12, the bottom plate 48 is not provided in the battery pack 30 . The battery pack 30 of this modification can also be used in the battery system 50 including the cooling plate 60 described above. In the battery system 50 using the battery pack 30 of this modified example, the lower ends (one ends) of the frame side walls 41A, 41B, 42A, and 42B of the frame 40 come into contact with the cooling plate 60 . Battery pack 30 is installed on cooling plate 60 by attaching frame 40 to cooling plate 60 with bolts or the like.

In the battery system 50 using the battery pack 30 of this modified example, the sheet bottom surface 47 of the sheet member 45 adheres (sticks) to the cooling plate 60 . In the example of FIG. 12 , the layer (third layer) 53 of the sheet member 45 is in close contact with the cooling plate 60 .

Also in this modification, the heat from the battery module 31 is appropriately transferred to the cooling plate 60 through the sheet member 45 . Moreover, since the sheet member 45 is also provided in the battery pack 30 of this modified example, an insulating structure with high voltage resistance (dielectric strength) is appropriately formed.

Note that in a modification, the sheet member 45 may be formed in a four-layer structure of layers 51 to 54 in a configuration in which the bottom plate 48 is not provided as in the third modification. Further, in another modified example, the sheet member 45 may be formed in a two-layer structure of layers 51 and 52 in a configuration in which the bottom plate 48 is not provided as in the third modified example.

Also, the number of batteries 1 forming the battery module 31 is not limited to six, and may be any number. Also, the battery pack 30 may be provided with a plurality of battery modules. For example, in a fourth modification shown in FIGS. 13 and 14, the battery pack 30 is provided with three battery modules 31A to 31C. In this modified example, each of the battery modules 31A to 31C includes eight batteries 1. FIG. In each of the battery modules 31A to 31C, a plurality of batteries 1 are arranged and a partition plate 36 and an adhesive 37 are provided in the same manner as in the battery module 31 described above.

Also, in the battery pack 30 of this modified example, as in the above-described embodiment, the vertical direction (the directions indicated by arrows X3 and X4) and the height direction (perpendicular or substantially perpendicular) intersecting with the longitudinal direction (directions indicated by arrows Z3 and Z4) and a width direction that intersects (perpendicular or nearly perpendicular) both the longitudinal direction and the height direction are defined. In each of the battery modules 31A to 31C, the arrangement direction of the batteries 1 matches or substantially matches the vertical direction of the battery pack 30 . Here, FIG. 13 schematically shows the battery pack 30 as viewed from one side (arrow Z3 side) in the height direction. 14 schematically shows the battery pack 30 in a cross section perpendicular or substantially perpendicular to the longitudinal direction (the direction in which the batteries 1 are arranged in each of the battery modules 31A to 31C).

Battery pack 30 also includes frame 40 in this modification. The frame 40 has frame side walls 41A, 41B, 42A to 42D. Frame side wall 41A faces battery modules 31A to 31C from one side (arrow X3 side) in the vertical direction of battery pack 30, respectively. In addition, frame side wall 41B faces battery modules 31A to 31C from the opposite side (arrow X4 side) of frame side wall 41A in the vertical direction of battery pack 30 . Battery module 31A is arranged between frame side walls 42A and 42B in the width direction of battery pack 30 . The battery module 31B is arranged between the frame side walls 42B and 42C in the width direction of the battery pack 30, and the battery module 31C is arranged between the frame side walls 42B and 42C in the width direction of the battery pack 30. .

Due to the configuration as described above, the frame side walls 41A, 41B, 42A, and 42B form an enclosing frame that surrounds the outer peripheral side of the battery module 31A. Frame side walls 41A, 41B, 42A, and 42B form storage space 43A in which battery module 31A is stored. Similarly, the frame side walls 41A, 41B, 42B, and 42C form a surrounding frame surrounding the outer peripheral side of the battery module 31B and form a storage space 43B in which the battery module 31B is stored. The frame side walls 41A, 41B, 42C, and 42D form a surrounding frame surrounding the outer peripheral side of the battery module 31C and form a storage space 43C in which the battery module 31C is stored. In battery pack 30, storage spaces 43A-43C are partitioned from each other by frame 40 (frame side walls 42B, 42C).

A plurality of bus bars 38 are also provided in the battery pack 30 in this modification. In each of the battery modules 31A-31C, each of the plurality of batteries 1 is electrically connected to the other battery via the busbar . Also, each of the battery modules 31A to 31C is electrically connected to the other battery modules (corresponding two of the battery modules 31A to 31C) and the external terminals of the battery pack 30 via the busbars .

Battery pack 30 also includes sheet members 45A to 45C. Each of the sheet members 45A-45C has the same configuration as any of the sheet members 45 of the previous embodiment, etc., and in this modified example, each of the sheet members 45A-45C includes the layers 51-53 described above.

In this modified example, the sheet upper surface 46 of the sheet member 45A adheres (adheres) to the module bottom surface 32 of the battery module 31A. Then, the layer (first layer) 51 of the sheet member 45A is compressed at the portion where the module bottom surface 32 of the battery module 31A abuts. Similarly, the sheet upper surface 46 of the sheet member 45B adheres (adheres) to the module bottom surface 32 of the battery module 31B. Then, the layer (first layer) 51 of the sheet member 45B is compressed at the portion where the module bottom surface 32 of the battery module 31B abuts. Further, the sheet upper surface 46 of the sheet member 45C adheres (adheres) to the module bottom surface 32 of the battery module 31C. Then, the layer (first layer) 51 of the sheet member 45C is compressed at the portion where the module bottom surface 32 of the battery module 31C abuts.

Further, in the battery pack 30 of this modified example, the bottom plate (supporting member) 48 is attached to the frame 40 from the side facing the module bottom surface 32 of each of the battery modules 31A to 31C in the height direction of the battery pack 30 . In each of the sheet members 45A to 45C, the sheet bottom surface 47 is in close contact with the bottom plate 48. As shown in FIG. 13 and 14, the layer (third layer) 53 of each of the sheet members 45A-45C adheres to the bottom plate .

The battery pack 30 of this modification can also be used in the battery system 50 including the cooling plate 60 described above. In the battery system 50 using the battery pack 30 of this modified example, the bottom plate 48 contacts the cooling plate 60 .

In this modified example, the heat generated in the battery module 31A is appropriately transferred to the bottom plate 48 and the cooling plate 60 through the sheet member 45A. Similarly, the heat generated in the battery module 31B is properly transmitted to the bottom plate 48 and the cooling plate 60 through the sheet member 45B, and the heat generated in the battery module 31C is properly transmitted to the bottom plate 48 and the cooling plate 60 through the sheet member 45C. transmitted. Therefore, in the battery pack 30 of this modified example, heat is appropriately radiated from each of the battery modules 31A to 31C to the cooling plate 60 .

In addition, in this modification, the sheet member 45A that is in close contact with the module bottom surface 32 of the battery module 31A is formed of a material with high electrical insulation, and the sheet member 45A provides an insulating structure with high withstand voltage (dielectric strength). , properly formed. Similarly, each of the sheet members 45B and 45C appropriately forms an insulating structure with high withstand voltage (dielectric strength).

As described above, even in the battery pack 30 of the present modification, an insulating structure with high withstand voltage is formed, and heat is appropriately radiated from each of the battery modules 31A to 31C.

Further, in a modification, unlike the third modification, the bottom plate 48 is not provided in the configuration in which the battery pack 30 is provided with a plurality of battery modules (eg, 31A to 31C) as in the fourth modification. good too. In this case, in the battery system 50 in which the battery pack 30 is used, the lower ends (one ends) of the frame side walls (eg 41A, 41B, 42A to 42D) come into contact with the cooling plate 60 . Each of the sheet members (eg, 45A to 45C) adheres (adheres) to the cooling plate 60 at the sheet bottom surface 47 .

According to at least one of these embodiments or examples, the frame is formed of an electrically insulating resin, and the frame side wall of the frame forms the storage space for the battery modules. Then, a sheet member is formed from an electrically insulating resin, and the sheet member includes a first layer adhering to the module bottom surface of the battery module and the first layer on the side opposite to the side on which the battery module is located. and a second layer laminated to. And the first layer is more thermally conductive and compressible than the frame and the second layer. As a result, an insulating structure with high withstand voltage is formed, and a battery pack capable of appropriately dissipating heat from the battery module can be provided.

While several embodiments of the invention have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and equivalents thereof.
The matters described in the scope of claims at the time of filing of the present application are added below.
[1] A battery module comprising a plurality of arranged batteries, having a module bottom surface facing one side in a height direction intersecting the arrangement direction of the plurality of batteries, and each of the plurality of batteries , a battery module comprising an electrode group and a metal outer container in which the electrode group is housed;
a frame having frame side walls extending along the height direction and formed of an electrically insulating resin, the frame forming a storage space for the battery module by the frame side walls;
A sheet member formed of an electrically insulating resin, the first layer adhering to the module bottom surface of the battery module, and a sheet member on the opposite side of the height direction to the side on which the battery module is located. a second layer laminated to the first layer, wherein the first layer has higher thermal conductivity and compressibility than the frame and the second layer, and the a first layer comprising a sheet member that is compressed at a portion of the battery module with which the bottom surface of the module abuts;
A battery pack comprising:
[2] each of the plurality of batteries comprises an electrode terminal;
the outer container of each of the plurality of batteries includes a container bottom surface forming the module bottom surface,
the first layer comprises a container receiving portion that abuts a corresponding one of the plurality of batteries on the container bottom surface of the outer container;
The amount of compression of the first layer in each of the container receiving portions is based on the dimension in the height direction from the bottom surface of the container to the electrode terminal in the corresponding one of the plurality of batteries. become,
The battery pack of [1].
[3] The outer surface of the sheet member has a bottom surface of the sheet facing the side opposite to the side on which the battery module is positioned in the height direction,
In each of the plurality of batteries, the distance in the height direction from the bottom surface of the sheet member to the electrode terminal is the same or substantially the same as that of the other batteries.
The battery pack of [2].
[4] The battery pack according to any one of [1] to [3], wherein the second layer has higher mechanical strength than the first layer.
[5] The battery pack according to any one of [1] to [4], wherein the second layer is thinner than each of the frame sidewall and the first layer.
[6] the first layer comprises silicone;
The second layer contains any one or more of polyethylene terephthalate, polyimide, polypropylene, and polybutylene terephthalate,
The battery pack according to any one of [1] to [5].
[7] The sheet member comprises a third layer laminated on the second layer on the side opposite to the side on which the first layer is laminated,
the third layer has higher thermal conductivity than the frame and the second layer;
The battery pack according to any one of [1] to [6].
[8] The sheet member comprises a fourth layer laminated on the third layer on the side opposite to the side on which the first layer and the second layer are laminated,
the third layer has higher adhesiveness than the second layer and the fourth layer;
The battery pack of [7].
[9] A bottom plate made of metal and supporting the battery module and the sheet member from the side facing the bottom surface of the module in the height direction, wherein heat is transferred from the battery module through the sheet member The battery pack according to any one of [1] to [6], further comprising a bottom plate.
[10] The sheet member comprises a third layer laminated on the second layer on the side opposite to the side on which the first layer is laminated,
the third layer has higher thermal conductivity than the frame and the second layer;
The battery pack of [9].
[11] The battery pack of [10], wherein the third layer has higher adhesiveness than the second layer and adheres to the bottom plate.
[12] The sheet member comprises a fourth layer laminated on the third layer on the side opposite to the side on which the first layer and the second layer are laminated,
the third layer has higher adhesiveness than the second layer and the fourth layer;
The battery pack of [10].
[13] The battery module comprises a partition plate disposed between the batteries that are adjacent to each other in the arrangement direction and having at least an outer surface formed of an electrically insulating material, [1] to [ 12], the battery pack according to any one of the above items.
[14] The battery pack according to any one of [1] to [13];
A cooling plate on which the battery pack is installed on an outer surface and which is provided on the opposite side of the sheet member in the height direction from the side on which the battery module is located, wherein heat is generated from the battery module through the sheet member. a cooling plate to which is transmitted;
A battery system comprising:

Claims (14)

A battery module comprising a plurality of arranged batteries, having a bottom surface of the module facing one side in a height direction intersecting the arrangement direction of the plurality of batteries, and each of the plurality of batteries comprising an electrode group. and a metal outer container in which the electrode group is housed; a battery module;
a frame having frame side walls extending along the height direction and formed of an electrically insulating resin, the frame forming a storage space for the battery module by the frame side walls;
A sheet member formed of an electrically insulating resin, the first layer adhering to the module bottom surface of the battery module, and a sheet member on the opposite side of the height direction to the side on which the battery module is located. a second layer laminated to the first layer, wherein the first layer has higher thermal conductivity and compressibility than the frame and the second layer, and the a first layer comprising a sheet member that is compressed at a portion of the battery module with which the bottom surface of the module abuts;
and
The sheet member has a sheet upper surface that abuts on the module bottom surface of the battery module,
The upper surface of the sheet is formed from the first layer, and the second layer is not exposed on the upper surface of the sheet.
battery pack. each of the plurality of batteries comprises an electrode terminal;
the outer container of each of the plurality of batteries includes a container bottom surface forming the module bottom surface,
the first layer comprises a container receiving portion that abuts a corresponding one of the plurality of batteries on the container bottom surface of the outer container;
The amount of compression of the first layer in each of the container receiving portions is based on the dimension in the height direction from the bottom surface of the container to the electrode terminal in the corresponding one of the plurality of batteries. become,
The battery pack of claim 1. the outer surface of the sheet member has a sheet bottom surface facing in the height direction opposite to the side on which the battery module is located;
In each of the plurality of batteries, the distance in the height direction from the bottom surface of the sheet member to the electrode terminal is the same or substantially the same as that of the other batteries.
The battery pack of claim 2. The battery pack according to any one of claims 1 to 3, wherein said second layer has higher mechanical strength than said first layer. 5. The battery pack of any one of claims 1-4, wherein the second layer is thinner than each of the frame sidewalls and the first layer. the first layer comprises silicone;
The second layer contains any one or more of polyethylene terephthalate, polyimide, polypropylene, and polybutylene terephthalate,
The battery pack according to any one of claims 1 to 5. The sheet member comprises a third layer laminated on the second layer on the side opposite to the side on which the first layer is laminated,
the third layer has higher thermal conductivity than the frame and the second layer;
The battery pack according to any one of claims 1 to 6. The sheet member comprises a fourth layer laminated on the third layer on the side opposite to the side on which the first layer and the second layer are laminated,
the third layer has higher adhesiveness than the second layer and the fourth layer;
The battery pack of claim 7. a bottom plate formed of metal and supporting the battery module and the sheet member from the side facing the bottom surface of the module in the height direction, the bottom plate through which heat is transferred from the battery module through the sheet member; 7. The battery pack of any one of claims 1-6, comprising: The sheet member comprises a third layer laminated on the second layer on the side opposite to the side on which the first layer is laminated,
the third layer has higher thermal conductivity than the frame and the second layer;
The battery pack of claim 9. 11. The battery pack of claim 10, wherein the third layer is more sticky than the second layer and sticks to the bottom plate. The sheet member comprises a fourth layer laminated on the third layer on the side opposite to the side on which the first layer and the second layer are laminated,
the third layer has higher adhesiveness than the second layer and the fourth layer;
11. The battery pack of claim 10. 13. The battery module according to any one of claims 1 to 12, further comprising a partition plate disposed between the batteries adjacent to each other in the arrangement direction and having at least an outer surface made of a material having electrical insulation. 1. Battery pack. A battery pack according to any one of claims 1 to 13;
A cooling plate on which the battery pack is installed on an outer surface and which is provided on the opposite side of the sheet member in the height direction from the side on which the battery module is located, wherein heat is generated from the battery module through the sheet member. a cooling plate to which is transmitted;
A battery system comprising:

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