Patent ID: 12218369

DETAILED DESCRIPTION

According to one embodiment, a battery module includes four or more batteries and a case in which the four or more batteries are housed. The four or more batteries include a first battery, a second battery adjacent to the first battery in a first direction, a third battery adjacent to the first battery in a second direction intersecting the first direction, and a fourth battery adjacent to the third battery in the first direction and adjacent to the second battery in the second direction. The case includes a first partition wall that partitions the first battery and the second battery and partitions the third battery and the fourth battery in the first direction, and a second partition wall that partitions the first battery and the third battery and partitions the second battery and the fourth battery in the second direction. The case includes a first case member, a second case member coupled to the first case member from one side in a third direction intersecting both the first direction and the second direction, and a fastening member fastening the first case member to the second case member at an intersection of the first partition wall and the second partition wall. The case includes at least one of a first rib protruding in the first direction on a surface of the first partition wall and a second rib protruding in the second direction on a surface of the second partition wall.

According to one embodiment, a battery pack including the above battery module is provided.

According to one embodiment, a vehicle including the above battery pack is provided.

Hereinafter, embodiments will be described with reference to drawings. A battery module according to an embodiment includes a plurality of batteries.

[Battery]

First, a single battery used in a battery module according to an embodiment will be described.FIGS.1and2show an example of a single battery1used in a battery module. The battery1is, for example, a secondary battery.FIG.1shows the battery1disassembled into components.

As shown inFIGS.1and2, the battery1includes a container (outer portion)3. The container3is made of a metal, such as aluminum, an aluminum alloy, steel, or stainless steel. An inner cavity13is formed inside the container3. The battery1and the container3are each defined in terms of a depth direction (direction indicated by arrows X1and X2), a lateral direction (direction indicated by arrows Y1and Y2) intersecting (perpendicular to or substantially perpendicular to) the depth direction, and a height direction (direction indicated by arrows Z1and Z2) intersecting (perpendicular to or substantially perpendicular to) both the depth direction and the lateral direction.

The container3includes a container body5and a lid member6. In the example ofFIG.1, etc., the container body5has a bottom wall11and a peripheral wall12, and is formed in a substantially rectangular parallelepiped shape with one surface opened. The bottom wall11is positioned on one side (arrow Z2side) in the height direction with respect to the inner cavity13. The peripheral wall12extends along a peripheral direction of the container3, and an outer peripheral side of the inner cavity13is surrounded by the peripheral wall12. The inner cavity13is open in the height direction toward a side (arrow Z1side) opposite to a side in which the bottom wall11is positioned. In the battery1and container3, a side on which the inner cavity (internal space)13is positioned with respect to the peripheral wall12is referred to as an inner peripheral side, and a side opposite to the inner peripheral side is referred to as an outer peripheral side.

The peripheral wall12includes two pairs of side walls15and16. The pair of side walls (first side walls) face each other with the inner cavity13interposed therebetween in the depth direction. The pair of side walls (second side walls)16face each other with the inner cavity13interposed therebetween in the lateral direction. Each of the side walls15continuously extends in the lateral direction between the side walls16. Each of the side walls16continuously extends in the depth direction between the side walls15.

The lid member6is attached to the container body5in the opening of the inner cavity13. The lid member6closes the opening of the inner cavity13and is attached to the peripheral wall12from the side opposite to the bottom wall11in the height direction. Therefore, the lid member6faces the bottom wall11with the inner cavity13interposed therebetween in the height direction. In the example ofFIG.1, etc., the lid member6is provided in a state in which the thickness direction of the lid member6corresponds to or substantially corresponds to the height direction of the battery1.

In the example ofFIG.1, etc., the dimension in the depth direction between the pair of side walls15is much smaller than each of the dimension in the height direction between the bottom wall11and the lid member6and the dimension in the lateral direction between the pair of side walls16. Therefore, the inner cavity13has a much smaller dimension in the depth direction than each of the dimension in the lateral direction and the dimension in the height direction. The container3is formed to have a uniform or substantially uniform thickness over the entire container3. Therefore, the battery1and the container3each have a much smaller dimension in the depth direction than each of the dimension in the lateral direction and the dimension in the height direction.

An electrode group10is housed in the inner cavity13of the container3.FIG.3is a view to explain the configuration the electrode group10. As shown inFIG.3, the electrode group10is formed into, for example, a flat shape, and includes a positive electrode21, a negative electrode22, and separators23and25. The positive electrode21includes a positive electrode current collecting foil21A as a positive electrode current collector, and a positive electrode active material-containing layer21B supported on a surface of the positive electrode current collecting foil21A. The positive electrode current collecting foil21A is an aluminum foil, an aluminum alloy foil, or the like, and has a thickness of 10 μm to 20 μm. A slurry containing a positive electrode active material, a binder, and an electro-conductive agent is applied to the positive electrode current collecting foil21A. Examples of the positive electrode active material include, but are not limited to, an oxide, a sulfide, a polymer, etc., that can occlude and release lithium. From the point of view of obtaining a high positive electrode electric potential, it is preferable to use a lithium manganese composite oxide, a lithium nickel composite oxide, a lithium cobalt composite oxide, a lithium iron phosphate, etc., as the positive electrode active material.

The negative electrode22includes a negative electrode current collecting foil22A as a negative electrode current collector, and a negative electrode active material-containing layer22B supported on a surface of the negative electrode current collecting foil22A. The negative electrode current collecting foil22A is an aluminum foil, an aluminum alloy foil, a copper foil, or the like, and has a thickness of 10 μm to 20 μm. A slurry containing a negative electrode active material, a binder, and an electro-conductive agent is applied to the negative electrode current collecting foil22A. Examples of the negative electrode active material include, but are not limited to, a metal oxide, a metal sulfide, a metal nitride, a carbon material, etc., that can occlude and release lithium. The negative electrode active material is preferably a material that occludes and releases lithium ions at a noble electric potential of 0.4 V or more in comparison to an electric potential of metal lithium, that is, a material that occludes and releases lithium ions at a noble electric potential of 0.4 V (vs. Li+/Li) or more. The use of a negative electrode active material which occludes and releases lithium ions at such a noble electric potential inhibits an alloy reaction between aluminum or an aluminum alloy and lithium, and this allows the use of aluminum or an aluminum alloy for the negative electrode current collecting foil22A and constituent members relating to the negative electrode22. Examples of the negative electrode active material which occludes and releases lithium ions at the noble electric potential of 0.4 V (vs. Li+/Li) or more include a titanium oxide, a lithium titanium composite oxide such as lithium titanate, a tungsten oxide, an amorphous tin oxide, a niobium titanium composite oxide, a tin silicon oxidate, a silicon oxide, etc., and it is particularly preferable to use a lithium titanium composite oxide as the negative electrode active material. When a carbon material which occludes and releases lithium ions is used as the negative electrode active material, a copper foil is preferably used as the negative electrode current collecting foil22A. A carbon material used as the negative electrode active material occludes and releases lithium ions at a noble electric potential of about 0 V (vs. Li+/Li).

It is desirable that an aluminum alloy used for the positive electrode current collecting foil21A and the negative electrode current collecting foil22A include one or two or more elements selected from Mg, Ti, Zn, Mn, Fe, Cu, and Si. A purity of aluminum and an aluminum alloy may be set to 98% by weight or more, and preferably 99.99% by weight or more. Furthermore, pure aluminum with a purity of 100% is usable as a material for the positive electrode current collector and/or the negative electrode current collector. A content of a transition metal such as nickel, chromium, etc., contained in aluminum and an aluminum alloy is preferably 100 wt. ppm or less (including 0 wt. ppm).

In the positive electrode current collecting foil21A, a long-side edge21C as one long-side edge, and its neighboring region, form the positive electrode current collecting tab21D. In the example ofFIG.2, the positive electrode current collecting tab21D is formed over the entire length of the long-side edge21C. In the positive electrode current collecting tab21D, the positive electrode active material-containing layer21B is not supported on the surface of the positive electrode current collecting foil21A. The positive electrode current collecting foil21A includes a positive electrode current collecting tab21D as a portion not supporting the positive electrode active material-containing layer21B. In the negative electrode current collecting foil22A, a long-side edge22C as one long-side edge, and its neighboring region, form the negative electrode current collecting tab22D. In the example ofFIG.2, the negative electrode current collecting tab22D is formed over the entire length of the long-side edge22C. In the negative electrode current collecting tab22D, the negative electrode active material-containing layer22B is not supported on the surface of the negative electrode current collecting foil22A. Therefore, the negative electrode current collecting foil22A includes the negative electrode current collecting tab22D as a portion where the negative electrode active material-containing layer22B is not supported.

Each of the separators23and25is made of a material having electrical insulation properties, and electrically insulates the positive electrode21from the negative electrode22. Each of the separators23and25may be a separate sheet, etc. from the positive electrode21and the negative electrode22, or may be integrated with one of the positive electrode21and the negative electrode22. The separators23and25may be made of an organic material, an inorganic material, or a mixture of an organic material and an inorganic material. Examples of an organic material that forms the separators23and25include engineering plastic and super engineering plastic. Examples of engineering plastics include polyamide, polyacetal, polybutylene terephthalate, polyethylene terephthalate, syndiotactic polystyrene, polycarbonate, polyamide imide, polyvinyl alcohol, polyvinylidene fluoride, modified polyphenylene ether, etc. Examples of super engineering plastics include polyphenylene sulfide, polyetheretherketone, liquid crystal polymer, polyvinylidene fluoride, polytetrafluoroethylene (PTFE), polyethernitrile, polysulfone, polyacrylate, polyetherimide, thermoplastic polyimide, etc. Examples of an inorganic material that forms the separators23and25include oxides (for example, aluminum oxide, silicon dioxide, magnesium oxide, phosphorus oxide, calcium oxide, iron oxide, and titanium oxide), and nitrides (for example, boron nitride, aluminum nitride, silicon nitride, and barium nitride), etc.

In the electrode group10, the positive electrode21, the negative electrode22, and the separators23and25are wound around winding axis B into a flat shape in a condition in which each of the separators23and25is interposed between the positive electrode active material-containing layer21B and the negative electrode active material-containing layer22B. The positive electrode21, the separator23, the negative electrode22, and the separator25are wound in a condition in which they are stacked together in this order. In the electrode group10, the positive electrode current collecting tab21D of the positive electrode current collecting foil21A protrudes from the negative electrode22and the separators23and25toward one side in the direction along the winding axis B. The negative electrode current collecting tab22D of the negative electrode current collecting foil22A protrudes from the positive electrode21and the separators23and25toward a side opposite to the side toward which the positive electrode current collecting tab21D protrudes in the direction along the winding axis B.

The electrode group10is arranged such that the winding axis B is parallel or substantially parallel to the lateral direction of the battery1. Thus, in the inner cavity13of the container3, the positive electrode current collecting tab21D protrudes from the negative electrode22and the separators23and25toward one side in the lateral direction. The negative electrode current collecting tab22D protrudes from the positive electrode21and the separators23and25to the side opposite to the side toward which the positive electrode current collecting tab21D protrudes in the lateral direction.

The electrode group10does not need to have a wound structure in which the positive electrode, the negative electrode, and the separators are wound. In an example, the electrode group10has 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 electrode and the negative electrode. In this case also, in the electrode group10, the positive electrode current collecting tab protrudes from the negative electrode toward one side in the lateral direction of the battery1(container3). In the electrode group10, the negative electrode current collecting tab protrudes from the positive electrode toward a side opposite to the side toward which the positive electrode current collecting tab protrudes in the lateral direction of the battery1.

In an example, inside the inner cavity13, the electrode group10is impregnated with an electrolytic solution (not shown). As the electrolytic solution, a nonaqueous electrolytic solution is used, and for example, a nonaqueous electrolytic solution prepared by dissolving an electrolyte in an organic solvent is used. In this case, examples of the electrolyte dissolved in the organic solvent include lithium salts such as lithium perchlorate (LiClO4), lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium hexafluoroarsenate (LiAsF6), lithium trifluoromethanesulfonate (LiCF3SO3), lithium bistrifluoromethylsulfonylimide [LiN(CF3SO2)2], etc., and mixtures thereof. Examples of the organic solvent include cyclic carbonates such as propylene carbonate (PC), ethylene carbonate (EC), and vinylene carbonate; linear carbonates such as diethyl carbonate (DEC), dimethyl carbonate (DMC), and methyl ethyl carbonate (MEC); cyclic ethers such as tetrahydrofuran (THF), 2-methyltetrahydrofuran (2MeTHF) and dioxolane (DOX); linear ethers such as dimethoxyethane (DME) and diethoxyethane (DEE); and γ-Butyrolactone (GBL), acetonitrile (AN), and sulfolane (SL). These organic solvents are used alone or as a mixed solvent.

In an example, as the nonaqueous electrolyte, a gel nonaqueous electrolyte in which a nonaqueous electrolytic solution and a polymer material are combined is used instead of the electrolytic solution. In this case, the above-described electrolyte and organic solvent are used. Examples of the polymer material include polyvinylidene fluoride (PVdF), polyacrylonitrile (PAN), and polyethylene oxide (PEO).

In an example, instead of the electrolytic solution, a solid electrolyte such as a high-polymer solid electrolyte, an inorganic solid electrolyte, etc., is provided as a nonaqueous electrolyte. In this case, the electrode group10may not be provided with the separators23and25. In the electrode group10, instead of the separators23and25, a solid electrolyte is interposed between the positive electrode21and the negative electrode22. Thus, in this example, the solid electrolyte achieves electrical isolation between the positive electrode21and the negative electrode22. In an example, an aqueous electrolyte containing an aqueous solvent may be used as the electrolyte instead of the nonaqueous electrolyte.

In the battery1, a pair of electrode terminals27are attached to an outer surface of the lid member6, that is, a surface of the lid member6facing the side opposite to the bottom wall11. One of the electrode terminals27is a positive electrode terminal of the battery1while the other is a negative electrode terminal. Each of the electrode terminals27is attached to the outer surface of the lid member6in a state of being exposed to the outside. In the battery1, the electrode terminals27are separated from each other in the lateral direction. The center position of the battery1in the lateral direction is located between the electrode terminals27. Each of the electrode terminals27is made of an electro-conductive material, for example, any one of aluminum, copper, stainless steel, and the like.

A pair of insulating members28made of an electrically insulating material are provided on the outer surface of the lid member6. Each of the insulating members28is interposed between the outer surface of the lid member6and a corresponding one of the electrode terminals27, and electrically insulates the corresponding one of the electrode terminals27from the container3. The insulating members28are arranged on sides opposite to each other with the center position of the battery1interposed therebetween in the lateral direction.

The positive electrode current collecting tab21D of the electrode group10is bundled by welding such as ultrasonic welding. The bundle of the positive electrode current collecting tab21D is electrically connected to a corresponding one (positive electrode terminal) of the electrode terminals27via one or more positive electrode leads including a positive electrode backup lead31A, a positive electrode lead32A, and the like. At this time, the connection between the positive electrode current collecting tab21D and the positive electrode lead, the connection between the positive electrode leads, and the connection between the positive electrode lead and the positive electrode terminal are made by welding such as ultrasonic welding. Here, the positive electrode lead is made of a conductive metal. The positive electrode current collecting tab21D and the positive electrode lead are electrically insulated from the container3by an insulating member (not shown) or the like.

Similarly, the negative electrode current collecting tab22D of the electrode group10is bundled by welding such as ultrasonic welding. The bundle of the negative electrode current collecting tab22D is electrically connected to a corresponding one (negative electrode terminal) of the electrode terminals27via one or more negative electrode leads including a negative electrode backup lead31B, a negative electrode lead32B, and the like. At this time, the connection between the negative electrode current collecting tab and the negative electrode lead, the connection between the negative electrode leads, and the connection between the negative electrode lead and the negative electrode terminal are made by welding such as ultrasonic welding. Here, the negative electrode lead is made of a conductive metal. The negative electrode current collecting tab and the negative electrode lead are electrically insulated from the container3by an insulating member (not shown) or the like.

In an example, the lid member6may be provided with a gas release valve and a liquid inlet (neither shown inFIGS.1to3). When the lid member6is provided with a liquid inlet, a sealing plate (not shown inFIGS.1to3) for closing the liquid inlet is welded to the outer surface of the lid member6.

In the above-described example, etc., a single electrode group10is housed in the inner cavity13of the container3, but it is not limited thereto. In an example, a plurality of electrode groups may be housed in the inner cavity13of the container3.

[Battery Module]

Next, a battery module including a plurality of batteries such as the above-described battery1will be described.

First Embodiment

First, a battery module according to the first embodiment will be described.FIGS.4to7show an example of a battery module40of the first embodiment. As shown inFIGS.4to7, etc., the battery module40is defined in terms of a first direction (direction indicated by arrows X3and X4), a second direction (direction indicated by arrows Y3and Y4) intersecting (perpendicular or substantially perpendicular to) the first direction, and a third direction (direction indicated by arrows Z3and Z4) intersecting (perpendicular or substantially perpendicular to) both the first direction and the second direction. Here,FIG.5illustrates a state viewed from one side in the first direction, andFIGS.6and7illustrate a state viewed from one side in the third direction.

In the battery module40, four or more of the aforementioned batteries1are provided, and in an example ofFIGS.4to7, eight batteries1are provided. In the battery module40, two (the first number of) battery rows41A and41B are formed. Each of the battery rows41A and41B includes four (the second number of) batteries1arrayed along the second direction. Therefore, when the number of battery rows (41A,41B) formed in the battery module40is defined as the first number while the number of batteries1arrayed in each battery row (41A,41B) is defined as the second number, the second number is larger than the first number. The battery rows41A and41B are adjacent to each other in the first direction. The battery rows41A and41B are not deviated or are rarely deviated from each other in the second direction and the third direction.

In each of the battery rows41A and41B, each of the batteries1is arranged in a state in which the lateral direction is along an array direction (second direction), that is, in a state in which the lateral direction corresponds to or substantially corresponds to the array direction. In each of the battery rows41A and41B, each of the batteries1is arranged in a state in which the depth direction corresponds to or substantially corresponds to the first direction, and the height direction corresponds to or substantially corresponds to the third direction. That is, in each of the battery rows41A and41B, each of the batteries1is arranged in a state in which the depth direction is along the first direction and the height direction is along the third direction. In each of the battery rows41A and41B, the batteries1are not deviated or are rarely deviated from each other in the first direction and the third direction.

The battery module40includes a case42. In the battery module40, each of the batteries1is housed in a storage cavity43inside the case42. In the storage cavity43, as described above, a plurality of (eight in the example ofFIGS.4to7) batteries1are provided, and a plurality of (two in the example ofFIGS.4to7) battery rows41A and41B are formed. The case42includes a first case member45and a second case member46. The first case member45and the second case member46are each made of an electrically insulating material such as resin. The second case member46is coupled to the first case member45from one side (arrow Z3side) in the third direction.

The case42including the case members45and46has a case bottom wall51, a case top wall52, and a case peripheral wall53, and is formed to have a substantially rectangular parallelepiped shape. The case bottom wall51is positioned on one side (arrow Z4side) in the third direction with respect to the storage cavity43(the container3of each battery1). The case top wall52is positioned on the side opposite to the side where the case bottom wall51is positioned with respect to the storage cavity43(the container3of each battery1) in the third direction. Therefore, the storage cavity43is formed between the case bottom wall51and the case top wall52in the third direction.

In each of the batteries1, the outer surface of the bottom wall11faces the side where the case bottom wall51is positioned in the third direction. In each of the batteries1, the outer surface of the lid member6faces the side where the case top wall52is positioned in the third direction. Therefore, the outer surface of the lid member6of each of the batteries1faces the side where the second case member46is positioned with respect to the first case member45. The case peripheral wall53extends along the peripheral direction of the case42(battery module40) between the case bottom wall51and the case top wall52. The outer peripheral side of the storage cavity43is surrounded by the case peripheral wall53. In each of the battery module40and the case42, the side where the storage cavity (internal space)43is positioned with respect to the case peripheral wall53is defined as an inner peripheral side, and a side opposite to the inner peripheral side is defined as an outer peripheral side.

In the case42, the case bottom wall51is formed by the first case member45, and the case top wall52is formed by the second case member46. The case peripheral wall53is formed by both the first case member45and the second case member46. In the case peripheral wall53, the case members45and46are brought into contact with each other at or near the central position in the third direction. In the case peripheral wall53, a boundary portion between the case members45and46is formed along the peripheral direction of the case42. In the case peripheral wall53, the boundary portion between the case members45and46is formed over the entire periphery or substantially the entire periphery of the case42in the peripheral direction.FIG.6shows a state viewed from a side where the case top wall52is positioned in the third direction, with the second case member46being omitted.FIG.7shows a state viewed from a side where the case bottom wall51is positioned in the third direction.

The case peripheral wall53includes two pairs of case side walls55and56. The pair of case side walls (first case side walls)55face each other with the storage cavity43interposed therebetween in the first direction. The pair of case side walls (second case side walls)56face each other with the storage cavity43interposed therebetween in the second direction. Each of the case side walls55extends continuously along the second direction between the case side walls56. Each of the case side walls56extends continuously along the first direction between the case side walls55.

In the present embodiment including the example ofFIGS.4to7, etc., the dimension in the first direction between the pair of case side walls55is smaller than each of the dimension in the second direction between the pair of case side walls56and the dimension in the third direction between the case bottom wall51and the case top wall52. Therefore, in each of the storage cavity43and the case42, the dimension in the first direction is smaller than the dimension in the second direction and the dimension in the third direction. The dimension in the second direction between the pair of case side walls56is larger than the dimension in the third direction between the case bottom wall51and the case top wall52. Therefore, in each of the storage cavity43and the case42, the dimension in the second direction is larger than the dimension in the third direction.

The case42includes a partition wall (first partition wall)57and a partition wall (second partition wall)58. In an example ofFIGS.4to7, one partition wall57is provided, and three partition walls58are provided. The partition walls57and58are each formed by both the first case member45and the second case member46. The partition walls57and58each extends continuously between the case bottom wall51and the case top wall52in the third direction. In each of the partition walls57and58, the case members45and46are brought into contact with each other at or near the central position in the third direction.FIG.5shows the partition wall57in a state viewed from one side in the first direction.

The partition wall57extends along the second direction in the storage cavity43and continuously extends between the case side walls56. In the partition wall57, a boundary portion between the case members45and46is formed along the second direction. The partition wall57is formed between the case side walls55in the first direction, and is formed at or near the center position of the case42in the first direction. The partition wall57partitions the battery rows41A and41B adjacent to each other in the first direction.

Each of the partition walls58extends along the first direction in the storage cavity43and continuously extends between the case side walls55. In each of the partition walls58, a boundary portion between the case member45and46is formed along the first direction. Further, each of the partition walls58is formed between the case side walls56in the second direction, and the partition walls58are arranged to be apart from each other in the second direction. In each of the battery rows41A and41B, a corresponding one of the partition walls58partitions the batteries1adjacent to each other in the second direction.

Since the partition walls57and58are formed as described above, eight spaces (rooms)61are formed in the storage cavity43in the example ofFIGS.4to7. The eight spaces61are isolated from each other by the partition walls57and58. In each of the spaces61, a corresponding one of the eight batteries1is arranged. In the storage cavity43, the volumes (areas) of the spaces61are equal or approximately equal to each other. The eight spaces61have a dimension in the first direction equal or approximately equal to each other, and have a dimension in the second direction equal or approximately equal to each other. The spaces61have a dimension in the third direction equal or approximately equal to each other.

FIG.8is an enlarged view of range A1ofFIG.6, andFIG.9is an A2-A2cross section ofFIG.7. As shown inFIGS.4to9, etc., in the case42, the first case member45is fastened to the second case member46by screw members63and67as fastening members, whereby the case members45and46are coupled to each other. In an example ofFIGS.4to9, etc., two screw members63and three screw members67are provided. Each of the screw members63fastens the case members45and46to each other at an intersection of a corresponding one of the case side walls56and the partition wall57. Each of the screw members67fastens the case members45and46to each other at an intersection of a corresponding one of the partition walls (second partition walls)58and the partition wall (first partition wall)57. Therefore, the screw members63and67are each arranged at or near the central position of the case42in the first direction.

In the first case member45, recessed portions62in a number equal to the number of the screw members63are formed, and recessed portions66in a number equal to the number of the screw members67are formed. In the second case member46, holes65in a number equal to the number of the screw members63are formed, and holes68in a number equal to the number of the screw members67are formed. The recessed portions62and the holes65are each formed at an intersection of a corresponding one of the case side walls56and the partition wall57. The recessed portions66and the holes68are each formed at an intersection of a corresponding one of the partition walls (second partition walls)58and the partition wall (first partition wall)57.

The recessed portions62and66are each recessed from the case bottom wall51toward a side where the second case member46is positioned in the third direction. The holes65and68each extend along the third direction from a boundary portion with the first case member45in the second case member46. Each of the recessed portions62communicates with a corresponding one of the holes65. Each of the recessed portions66communicates with a corresponding one of the holes68. The cross-sectional area of each of the holes65and68perpendicular to or substantially perpendicular to the third direction is smaller than the cross-sectional area of each of the recessed portions62and66perpendicular to or substantially perpendicular to the third direction.

Each of the screw members63and67includes a head portion (63A and67A, respectively), and a male screw portion (63B and67B, respectively) as an engagement portion. In each of the screw members63and67, the cross-sectional area of the head portion (63A;67A, respectively) perpendicular to or substantially perpendicular to the axial direction is larger than the cross-sectional area of the male screw portion (63B;67B, respectively) perpendicular to or substantially perpendicular to the axial direction. Further, in each of the screw members63and67, the cross-sectional area of the head portion (63A;67A, respectively) perpendicular to or substantially perpendicular to the axial direction is smaller than the cross-sectional area of each of the recessed portions62and66perpendicular to or substantially perpendicular to the third direction. In each of the screw members63and67, the cross-sectional area of the head portion (63A;67A, respectively) perpendicular to or substantially perpendicular to the axial direction is larger than the cross-sectional area of each of the holes65and68perpendicular to or substantially perpendicular to the third direction.

Each of the screw members63is inserted into a corresponding one of the recessed portions62. Each head portion63A of the screw member63comes into contact with a bottom surface of a corresponding one of the recessed portions62from the side where the case bottom wall51is positioned. A female screw portion (not shown) is formed on an inner peripheral surface of each of the holes65. Each male screw portion63B of the screw member63is inserted into a corresponding one of the holes65. Each male screw portion63B of the screw member63is screwed with the female screw portion in a corresponding one of the holes65. Thereby, each of the screw members63fastens the case members45and46to each other.

Similarly, each of the screw members67is inserted into a corresponding one of the recessed portions66. Each head portion67A of the screw member67comes into contact with a bottom surface of a corresponding one of the recessed portions66from a side where the case bottom wall51is positioned. A female screw portion (not shown) is formed on an inner peripheral surface of each of the holes68. Each male screw portion67B of the screw member67is inserted into a corresponding one of the holes68. Each male screw portion67B of the screw member67is screwed with the female screw portion in a corresponding one of the holes68. Thereby, each of the screw members67fastens the case members45and46to each other.

As described above, in each of the screw members63and67as fastening members, the head portion (a corresponding one of respective63A and67A) comes into contact with a bottom surface of a corresponding one of the respective recessed portions62and66from the side where the case bottom wall51is positioned. In each of the screw members63and67, an engagement portion such as a male screw portion (a corresponding one of respective63B and67B) is inserted into a corresponding one of the respective holes65and68, and engages with the second case member46in a corresponding one of the respective holes65and68.

The partition wall (first partition wall)57has partition surfaces57A and57B. The partition surface (first partition surface)57A faces one side (arrow X3side) in the first direction, and the partition surface (second partition surface)57B faces the side opposite to the partition surface57A in the first direction. Each of the partition walls (second partition walls)58has partition surfaces58A and58B. On each of the partition walls58, the partition surface (third partition surface)58A faces one side (arrow Y3side) in the second direction, and the partition surface (fourth partition surfaces)58B faces the side opposite to the partition surface58A in the second direction.

A plurality of ribs (first ribs)71are formed on each of partition surfaces (surfaces)57A and57B of the partition wall57. On each of the partition surfaces57A and57B, each of the ribs71protrudes in the first direction. On the partition surface57A, each of the ribs71protrudes to the side (arrow X3side) toward which the partition surface57A faces in the first direction. On the partition surface57B, each of the ribs71protrudes to the side (arrow X4side) toward which the partition surface57B faces in the first direction. In an example ofFIGS.4to9, etc., each of the ribs71extends continuously between the case bottom wall51and the case top wall52in the third direction.

In each of the partition surfaces57A and57B, the plurality of ribs71are arranged apart from each other in the second direction. In an example ofFIGS.4to9, etc., the number of ribs71formed on the partition surface (first partition surface)57A is the same as the number of ribs71formed on the partition surface (second partition surface)57B. Each of the ribs71formed on the partition surface57A does not deviate or rarely deviates from a corresponding one of the ribs71formed on the partition surface57B in the second direction. Therefore, the ribs71are arranged symmetrically (plane-symmetrically) or substantially symmetrically (substantially plane-symmetrically) with the partition wall57as the center (center plane).

In each of the partition walls58, a plurality of ribs (second ribs)72are formed on each of partition surfaces (surfaces)58A and58B. On each of the partition surfaces58A and58B of each of the partition walls58, each of the ribs72protrudes in the second direction. On the partition surface58A of each of the partition walls58, each of the ribs72protrudes to the side (arrow Y3side) toward which the partition surface58A faces in the second direction. On the partition surface58B of each of the partition walls58, each of the ribs72protrudes to the side (arrow Y4side) toward which the partition surface58B faces in the second direction. In an example ofFIGS.4to9, etc., each of the ribs72extends continuously between the case bottom wall51and the case top wall52in the third direction.

On each of the partition surfaces58A and58B of each of the partition walls58, the plurality of ribs72are arranged apart from each other in the first direction. In an example ofFIGS.4to9, etc., in each of the partition walls58, the number of ribs72formed on the partition surface (third partition surface)58A is the same as the number of ribs72formed on the partition surface (fourth partition surface)58B. On each of the partition walls58, each of the ribs72formed on the partition surface58A does not deviate or rarely deviates from a corresponding one of the ribs72formed on the partition surface58B in the first direction. Therefore, on each of the partition walls58, the ribs72are arranged symmetrically (plane-symmetrically) or substantially symmetrically (substantially plane-symmetrically) with the partition wall (a corresponding one of58) as the center (center plane).

In an example ofFIGS.4to9, etc., on the partition wall57, three ribs (first ribs)71protrude toward each of the spaces61(all of the eight spaces61in the example ofFIGS.4to9) adjacent to the partition wall57in the first direction. On each of the partition walls58, two ribs (second ribs)72protrude toward each of the spaces61(corresponding four of the eight spaces61in the example ofFIGS.4to9) adjacent to the partition wall (corresponding one of58) in the second direction. In an example ofFIGS.4to9, etc., three ribs71are arranged in each of the eight spaces61. Two ribs72are arranged in each of the four spaces61located at both ends in the second direction. Four ribs72are arranged in each of the four spaces61excluding the spaces61located at both ends in the second direction.

Here, any one of the eight batteries1is referred to as a battery (first battery)1α. Further, a battery (second battery)1β adjacent to the battery1α in the first direction and a battery (third battery)1γ adjacent to the battery1α in the second direction are defined. A battery (fourth battery)1δ adjacent to the battery1γ in the first direction and adjacent to the battery1β in the second direction is defined. In the battery module40, the partition wall (first partition wall) 57 partitions the batteries1α and1β and partitions the batteries1γ and1δ in the first direction. A partition wall58α which is a corresponding one of the partition walls (second partition walls)58partitions the battery1α and the battery1γ and partitions the battery1β and the battery1δ in the second direction. Therefore, the spaces61in which the batteries1α to1δ are arranged are isolated from each other by the partition wall57and58α. At the intersection of the partition walls57and58α, the case members45and46are fastened to each other by a corresponding one of the screw members (fastening members)67.

As described above, the plurality of ribs71protrude in the first direction on each of the partition surfaces57A and57B of the partition wall57, and the plurality of ribs72protrude in the second direction on each of the partition surfaces58A and58B of the partition wall58α. In each of the spaces61in which the batteries1α to1δ are housed, a corresponding one or more ribs71protruding from the partition wall57and a corresponding one or more ribs72protruding from the partition wall58α are arranged. In an example ofFIGS.4to9, etc., three ribs (first ribs)71protrude from the partition wall57toward each of the batteries1α to1δ. Two ribs (second ribs)72protrude from the partition wall58α toward each of the batteries1α to1δ.

FIG.10shows a partial range of the first case member45of the battery module40of the example shown inFIGS.4to9, etc., andFIG.11shows an enlarged view of a range A3ofFIG.10.FIG.12shows a partial range of the first case member45of the battery module40different from the range shown inFIG.10, andFIG.13shows a range A4ofFIG.12. As shown inFIGS.5,8,10to13, etc., crush ribs73A and73B are formed on the first case member45in addition to the ribs71and72described above. Each of the crush ribs73A and73B is arranged in the storage cavity43of the case42. In the storage cavity43, each of the crush ribs73A and73B is arranged at an end portion on the side where the case bottom wall51is positioned in the third direction. Each of the crush ribs73A and73B extends from the case bottom wall51along the third direction toward the side where the second case member46(case top wall52) is positioned.

In an example ofFIGS.4to13, etc., a plurality of crush ribs73A are formed on the inner surface of each of the case side walls55. On the inner surface of each of the case side walls55, each of the crush ribs73A protrudes inward in the first direction. Further, a plurality of crush ribs73A are formed on each of the partition surfaces57A and57B of the partition wall57. On each of the partition surfaces57A and57B of the partition wall57, each of the crush ribs73A further protrudes in the first direction from a corresponding one of the ribs71. On the partition surface57A, each of the crush ribs73A protrudes from a corresponding one of the ribs71to a side (arrow X3side) toward which the partition surface57A faces in the first direction. On the partition surface57B, each of the crush ribs73A protrudes from a corresponding one of the ribs71to a side (arrow X4side) toward which the partition surface57B faces in the first direction.

On each of the partition walls58as well, a plurality of crush ribs73A are formed on each of the partition surfaces (surfaces)58A and58B. On each of the partition surfaces58A and58B of each of the partition walls58, each of the crush ribs73A further protrudes in the second direction from a corresponding one of the ribs72. On the partition surface58A of each of the partition walls58, each of the crush ribs73A protrudes from a corresponding one of the ribs72to a side (arrow Y3side) toward which the partition surface58A faces in the second direction. On the partition surface58B of each of the partition walls58, each of the crush ribs73A protrudes from a corresponding one of the ribs72to a side (arrow Y4side) toward which the partition surface58B faces in the second direction.

In an example ofFIGS.4to13, etc., a plurality of crush ribs73B are formed on each of the partition surfaces57A and57B of the partition wall57. On each of the partition surfaces57A and57B of the partition wall57, each of the crush ribs73B protrudes in the first direction. On the partition surface57A, each of the crush ribs73B protrudes to a side (arrow X3side) toward which the partition surface57A faces in the first direction. On the partition surface57B, each of the crush ribs73B protrudes to a side (arrow X4side) toward which the partition surface57B faces in the first direction. The amount of protrusion of each of the crush ribs73A from the case side wall55and the corresponding one of the ribs71and72is smaller than the amount of protrusion of each of the crush ribs73B from the partition wall57.

In an example ofFIGS.4to13, etc., on the partition wall57, three crush ribs73A and two crush ribs73B protrude toward each of the spaces61(all of the eight spaces61in the example ofFIGS.4to13) adjacent to the partition wall57in the first direction. On each of the partition walls58, one crush rib73A protrudes toward each of the spaces61(corresponding four of the eight spaces61in the example ofFIGS.4to13) adjacent to the partition wall (corresponding one of58) in the second direction. On each of the pair of case side walls55, five crush ribs73A protrude toward each of the spaces61(corresponding four of the eight spaces61in the example ofFIGS.4to13) adjacent to the side wall (corresponding one of55) in the first direction.

In an example ofFIGS.4to13, etc., two crush ribs73B are arranged in each of the eight spaces61. Nine crush ribs73A are arranged in each of the four spaces61arranged at both ends in the second direction. Ten crush ribs73A are arranged in each of the four spaces61excluding the spaces61positioned at both ends in the second direction. In an example ofFIGS.4to13, etc., three crush ribs73A (ribs71) and two crush ribs73B are alternately arranged in the second direction at a region along the partition wall57of each of the spaces61.

Each of the crush ribs73A and73B includes an inclined surface77at an end portion on the side where the case bottom wall51is positioned in the third direction. In each of the crush ribs73A and73B, the inclined surface77is inclined such that the amount of protrusion increases toward the case bottom wall51. That is, in the inclined surface77of each of the crush ribs73A and73B, as a distance from the case bottom wall51increases, a distance from a root position of the protruding portion decreases.

FIG.14shows a partial range of the second case member46of the battery module40of the example shown inFIGS.4to9, etc. As shown inFIGS.5and14, etc., a plurality of crush ribs75are formed on the second case member46in addition to the above-described ribs71and72. Each of the crush ribs75is arranged in the storage cavity43of the case42. In the storage cavity43, each of the crush ribs75is arranged at an end portion on the side where the case top wall52is positioned in the third direction. Each of the crush ribs75extends from the case top wall52along the third direction toward the side where the first case member45(case bottom wall51) is positioned. Thus, each of the crush ribs75is arranged away from each of the crush ribs73A and73B in the third direction.

In the example shown inFIGS.4to14, etc., a plurality of crush ribs75are formed on the inner surface of each of the case side walls55. On the inner surface of each of the case side walls55, each of the crush ribs75protrudes inward in the first direction. Further, a plurality of crush ribs75are formed on each of the partition surfaces57A and57B of the partition wall57. On each of the partition surfaces57A and57B of the partition wall57, each of the crush ribs75further protrudes in the first direction from a corresponding one of the ribs71. On the partition surface57A, each of the crush ribs75protrudes from a corresponding one of the ribs71to a side (arrow X3side) toward which the partition surface57A faces in the first direction. On the partition surface57B, each of the crush ribs75protrudes from a corresponding one of the ribs71to a side (arrow X4side) toward which the partition surface57B faces in the first direction.

In an example ofFIGS.4to14, etc., on the partition wall57, three crush ribs75protrude toward each of the spaces61(all of the eight spaces61in the example ofFIGS.4to14) adjacent to the partition wall57in the first direction. In each of the pair of case side walls55, three crush ribs75protrude toward each of the spaces61(corresponding four of the eight spaces61in the example ofFIGS.4to14) adjacent to the side wall (corresponding one of55) in the first direction. In an example ofFIGS.4to14, etc., six crush ribs75are arranged in each of the eight spaces61.

FIG.15shows one of the eight spaces61.FIG.15shows a cross section passing through one of the crush ribs73A and one of the crush ribs73B in the space61. As shown inFIG.15, etc., in each of the spaces61, each of the crush ribs73A and73B is pressed in the first direction or the second direction by the peripheral wall12of the corresponding one of the batteries1. In each of the spaces61, each of the crush ribs73A and73B is pressed toward the side where the case bottom wall51is positioned in the third direction by the bottom wall11of the corresponding one of the batteries1. Therefore, in each of the spaces61, each of the crush ribs73A and73B is crushed by pressing from the corresponding one of the batteries1. Further, in each of the spaces61, each of the crush ribs75is pressed in the first direction or the second direction by the peripheral wall12of the corresponding one of the batteries1. Therefore, in each of the spaces61, each of the crush ribs75is crushed by pressing from the corresponding one of the batteries1.

In each of the spaces61, the inclined surface77of each of the crush ribs73A and73B presses a corresponding one of the batteries1toward the side where the case top wall52is positioned in the third direction. Therefore, each of the eight batteries1is pressed toward the side where the case top wall52is positioned in the third direction by the inclined surface77of each of the crush ribs73A and73B in the corresponding one of the spaces61. Each of the batteries1comes into contact with the inner surface of the case top wall52by being pressed by the crush ribs73A and73B. In each of the batteries1, the pair of electrode terminals27protrude outward in the third direction with respect to the inner surface of the case top wall52. In an example, the case top wall52is formed with one or more holes (not shown) that allow the outside of the case42to communicate with the storage cavity43. Each of the electrode terminals27of each of the batteries1is exposed to the outside of the case42through any of the holes formed on the case top wall52.

In the battery module40, one or more bus bars (not shown) are used to electrically connect the plurality of batteries1to each other. The bus bar is made of an electro-conductive material such as a metal. In the battery module40, a plurality of batteries1may be electrically connected in series, or a plurality of batteries1may be electrically connected in parallel. The battery module40may be provided with both a series connection in which the batteries1are connected in series and a parallel connection in which the batteries1are connected in parallel. When two batteries1are electrically connected using one bus bar, the bus bar connects a positive electrode terminal of one of the two batteries1and a negative electrode terminal of the other of the two batteries1. When two or more batteries1are electrically connected in parallel using two bus bars, one of the two bus bars connects the positive electrode terminals of the two or more batteries1. The other of the two bus bars connects the negative electrode terminals of two or more batteries1.

In the battery module40of the present embodiment, the screw members63and67as fastening members fasten the case members45and46. By fastening with the screw members63and67, the plurality of case members45and46forming the case42are coupled to each other. Therefore, the case member45and46are coupled without using an adhesive or the like.

In the battery module40, each of the screw members67fastens the case members45and46to each other at an intersection of a corresponding one of the partition walls (second partition walls)58and the partition wall (first partition wall)57. Therefore, each of the screw members67fastens the case member45and46at a portion between the case side walls55in the first direction and between the case side walls56in the second direction. That is, each of the screw members67fastens the case member45and46at a portion on the inner peripheral side with respect to the case peripheral wall53. By fastening the case members45and46at a portion on the inner peripheral side with respect to the case peripheral wall53, the plurality of case members45and46forming the case42are firmly coupled to each other.

In the battery module40, the second number, which is the number of batteries1arrayed in each of the battery rows (41A,41B), is larger than the first number, which is the number of battery rows (41A,41B) formed. In the battery module40, the dimension in the second direction is larger than each of the dimension in the first direction and the dimension in the third direction. In the battery module40, as described above, the case members45and46are fastened by the screw members67at one or more positions between the case side walls56in the second direction. Therefore, even in the battery module40with the case42having a large dimension in the second direction, the case members45and46are firmly coupled to each other. Firmly coupling the case members45and46ensures the strength of the case42even for the battery module40with the case42having a large dimension in the second direction.

In the battery module40, a plurality of ribs (first ribs)71protruding in the first direction are provided on each of the partition surfaces57A and57B of the partition wall57. A plurality of ribs (second ribs)72protruding in the second direction are provided on each of the partition surfaces58A and58B of each of the partition walls58. In each of the spaces61, movement of a corresponding one of the batteries1in the first direction is restricted by the ribs71. Similarly, in each of the spaces61, movement of a corresponding one of the batteries1in the second direction is restricted by the ribs72. Since movement of each of the batteries1is restricted by the ribs71and72as described above, each of the batteries1is firmly installed in a corresponding one of the spaces61.

The ribs71are arranged symmetrically (plane-symmetrically) or substantially symmetrically (substantially plane-symmetrically) with the partition wall57as the center (center plane). On each of the partition walls58, the ribs72are arranged symmetrically (plane-symmetrically) or substantially symmetrically (substantially plane-symmetrically) with the partition wall (a corresponding one of58) as the center (center plane). Therefore, a force is more directly applied to each of the ribs71and72from the battery1adjacent to the rib (corresponding one of71and72). Thus, each of the batteries1can be more reliably fixed (installed).

One or more crush ribs73A,73B, and75are arranged in each of the spaces61. In each of the spaces61, each of the crush ribs73A,73B, and75is crushed by the pressing from a corresponding one of the batteries1. Since the crush ribs73A,73B, and75are crushed as described above, in each of the spaces61, movement of the corresponding one of the batteries1in the first direction and the second direction is more reliably restricted. Therefore, each of the batteries1is more firmly installed in the corresponding one of the spaces61.

In the battery module40, since each of the batteries1is installed as described above, it is not necessary to bond the batteries1to the case42using an adhesive or the like. That is, each of the batteries1is firmly installed in a corresponding one of the spaces61without using an adhesive or the like.

In the battery module40, as described above, the movement of each of the batteries1in the first direction is restricted by the ribs71. Therefore, movement of each of the batteries1in the first direction is restricted without increasing the thickness (dimension in the first direction) of the partition wall57. Since the thickness of the partition wall57is not increased, the weight of the case42is reduced, and the weight of the battery module40is reduced.

In the battery module40, as described above, movement of each of the batteries1in the second direction is restricted by the ribs72. Therefore, movement of each of the batteries1in the second direction is restricted without increasing the thickness (dimension in the second direction) of each of the partition walls58. Since the thickness of each of the partition walls58is not increased, the weight of the case42is reduced, and the weight of the battery module40is reduced.

In the battery module40, each of the batteries1comes into contact with the inner surface of the case top wall52by the pressing from the crush ribs73A and73B. In each of the batteries1, the pair of electrode terminals27protrude outward in the third direction with respect to the inner surface of the case top wall52. That is, the electrode terminals27of each of the batteries1protrude from the inner surface of the case top wall52. The lid member6of each of the batteries1comes into contact with the inner surface of the case top wall52, and the position of the electrode terminals27of each of the batteries1in the third direction is fixed. Accordingly, a space is not formed between each of the electrode terminals27and the bus bar (not shown), and the bus bar can be easily brought into contact with each of the electrode terminals27. This improves the workability of the operation of electrically connecting the plurality of batteries1using the bus bars during the manufacture, etc. of the battery module40.

(Modifications)

The number of the ribs71provided on the partition wall57and the number of the ribs72provided on each of the partition walls58are not limited to those in the embodiment described above. In a modification, one or more ribs71protrude from the partition wall57toward each of the batteries1, and one or more ribs72protrude from a corresponding one of the partition walls58toward each of the batteries1. In this case also, movement of each of the batteries1in the first direction is restricted by the ribs71, and movement of each of the batteries1in the second direction is restricted by the ribs72. Further, with the ribs71provided, the thickness of the partition wall57is not increased, and with the ribs72provided, the thickness of each of the partition walls58is not increased. Therefore, the weight of the case42is reduced, and the weight of the battery module40is reduced, as in the above-described embodiment, etc.

In a modification, a rib (first rib)71is formed on the partition wall (first partition wall)57, but a rib (second rib)72is not formed on each of the partition walls (second partition walls)58. In this case, each of the partition walls58is formed thicker than when the rib72is provided. Movement of each the batteries1in the second direction is restricted by corresponding one or two of the partition walls58. In this modification as well, since the ribs71are provided, the thickness of the partition wall57is not increased. Therefore, in this modification also, the weight of the case42is reduced, and the weight of the battery module40is reduced.

In another modification, a rib (second rib)72is formed on each of the partition wall (second partition wall)58, but a rib (first rib)71is not formed on the partition wall (first partition wall)57. In this case, the partition wall57is formed thicker than when the rib71is provided. Movement of each of the batteries1in the first direction is restricted by the partition wall57. In this modification as well, since the rib72is provided, the thickness of each of the partition walls58is not increased. Therefore, in this modification also, the weight of the case42is reduced, and the weight of the battery module40is reduced.

The number of crush ribs73A and73B formed on the case42and the number of crush ribs75formed on the case42are not limited to those in the above-described embodiment. In a modification, one or more crush ribs73A or73B are arranged in each of the spaces61. In this modification as well, each of the batteries1comes into contact with the inner surface of the case top wall52by being pressed by the corresponding one of the crush ribs73A and73B in the corresponding one of the spaces61. In each of the batteries1, the pair of electrode terminals27protrude outward in the third direction with respect to the inner surface of the case top wall52.

In a modification, the crush rib75may not be provided. In another modification, the crush ribs73A and73B may not be provided. However, in these modifications as well, at least one of a rib (first rib)71protruding from the partition wall (first partition wall)57and a rib (second rib)72protruding from each of the partition walls (second partition walls)58is provided.

Further, the number of batteries1included in the battery module40is not limited to that in the above-described embodiment, etc. In any case, the battery module40includes four or more batteries1including batteries1α to1δ. Similarly to the above-described embodiment, etc., the battery (second battery)1β is adjacent to the battery (first battery)1α in the first direction, and the battery (third battery)1γ is adjacent to the battery1α in the second direction. The battery (fourth battery)1δ is adjacent to the battery1γ in the first direction, and adjacent to the battery1β in the second direction. In either case, the partition wall (first partition wall)57partitions the battery1α and the battery1β and partitions the battery1γ and the battery1δ in the first direction, and the partition wall (second partition wall)58partitions the battery1α and the battery1γ and partition the battery1β and the battery1δ in the second direction. At the intersection of the partition walls57and58, the first case member45is fastened to the second case member46by a fastening member such as the screw member67. The case42is provided with at least one of the rib (first rib)71protruding in the first direction on the surface of the partition wall57and the rib (second rib)72protruding in the second direction on the surface of the partition wall58.

In the case where the batteries1α to1δ are provided as described above, in the battery module40, the batteries1α and1γ form a battery row (first battery row)41A in which batteries1are arrayed along the second direction. The batteries1β to1δ form a battery row (second battery row)41B in which batteries1are arrayed along the second direction. The battery rows41A and41B are adjacent to each other in the first direction.

In an example, four or more batteries1including the batteries1α to1δ form the first number of battery rows including the battery rows41A and41B. In each of the first number of battery rows including the battery rows41A and41B, the second number of batteries1larger than the first number are arrayed along the second direction. In this case, in the battery module40, the dimension in the second direction is larger than each of the dimension in the first direction and the dimension in the third direction.

[Battery Pack]

Next, a description will be given of a battery pack in which the battery module according to the above-described embodiment, etc. is used.FIG.16shows an example of a battery pack80in which the battery module40of the embodiment shown inFIGS.4to15is used. In an example ofFIG.16, etc., in the battery module40, a plurality of batteries1are electrically connected in series. The batteries1are electrically connected to each other via the bus bar, etc. described above. In another example, in the battery module40, a plurality of batteries1may be electrically connected in parallel. In another example, the battery module40may be provided with both a series connection in which the batteries1are connected in series and a parallel connection in which the batteries1are connected in parallel.

In the battery module40of the battery pack80, a positive electrode terminal (a corresponding one of27) of a corresponding one of the plurality of batteries1is connected to a positive electrode-side module terminal91via a positive electrode side lead93, etc. In corresponding one of the batteries1other than the battery1to which the positive electrode side lead93is connected, a negative electrode terminal (a corresponding one of27) is connected to a negative electrode-side module terminal92via a negative electrode-side lead94.

The battery pack80is provided with a printed wiring board81. On the printed wiring board81, a protection circuit82, a thermistor83as a temperature detector, and an external terminal85for energization are mounted. In the battery pack80, an insulating member (not shown) prevents unnecessary connection between an electrical path on the printed wiring board81and a wiring of the battery module40. The positive electrode-side module terminal91is connected to the protection circuit82via a wiring86or the like formed on the printed wiring board81, and the negative electrode-side module terminal92is connected to the protection circuit82via a wiring87or the like formed on the printed wiring board81.

The thermistor83as a temperature detector detects a temperature of each of the plurality of batteries1forming the battery module40. The thermistor83outputs a detection signal for the temperature to the protection circuit82.

The battery pack80has a current detection function and a voltage detection function. In the battery pack80, an input current to the battery module40and an output current from the battery module40may be detected, and a current flowing through any of the batteries1forming the battery module40may be detected. In the battery pack80, a voltage of each of the batteries1may be detected in the battery module40, or a voltage applied to the entire battery module40may be detected. In the battery pack80, the battery module40and the protection circuit82are connected via the wiring84. A detection signal for the current and a detection signal for the voltage are output to the protection circuit82via the wiring84.

In an example, instead of detecting a voltage of each of the batteries1, a positive electrode electric potential or a negative electrode electric potential is detected for each of the batteries1forming the battery module40. In this case, the battery module40is provided with a lithium electrode or the like as a reference electrode. Then, the positive electrode electric potential or the negative electrode electric potential of each of the batteries1is detected with reference to an electric potential at the reference electrode.

The external terminal85is connected to a device outside the battery pack80. The external terminal85is used to output a current from the battery module40to the outside and/or input a current to the battery module40. When the battery module40of the battery pack80is used as a power source, a current is supplied to the outside of the battery pack80through the energization external terminal85. When the battery module40is charged, a charging current is supplied to the battery module40through the energization external terminal85. The charging current of the battery module40includes, for example, regenerative energy of power of a vehicle or the like. The protection circuit82can be connected to the external terminal85through a positive wiring88and a negative wiring89.

The protection circuit82has a function of blocking electrical connection between the battery module40and the external terminal85. The protection circuit82is provided with a relay, a fuse, or the like, as a connection blocking unit. The protection circuit82has a function of controlling charge and discharge of the battery module40. The protection circuit82controls charging and discharging of the battery module40based on a detection result of any one or more of the above-described current, voltage, temperature, and the like.

For example, when the temperature detected by the thermistor83becomes equal to or higher than a predetermined temperature, the protection circuit82determines that a predetermined condition is satisfied. When any one or more of overcharge, overdischarge, overcurrent, and the like are detected in the battery module40, the protection circuit82determines that the battery module40satisfies a predetermined condition. When it is determined that the battery module40satisfies the above-described predetermined condition, the protection circuit82can block the conduction between the protection circuit82and the energization external terminal85. When the conduction between the protection circuit82and the energization external terminal85is blocked, the output of the current from the battery module40to the outside and the input of the current to the battery module40are stopped. This effectively prevents continuous occurrence of an overcurrent or the like in the battery module40.

In an example, a circuit formed in a device using the battery pack80(battery module40) as a power supply may be used as a protection circuit. In the battery pack80, a plurality of battery modules40may be provided, and the battery modules40may be electrically connected in series and/or in parallel.

[Use of Battery Pack]

The configuration and the like of the battery pack80including the battery module40described above are appropriately changed depending on use. The battery pack80is preferably used in an apparatus or the like that is required to be charged and discharged with a large current. Specific use of the battery pack80includes a power supply of a digital camera, an on-vehicle power supply of a vehicle, and a stationary power supply. In this case, examples of the vehicle on which the battery pack80including the battery module40is mounted include a two- or four-wheeled hybrid electric vehicle, a two- or four-wheeled electric vehicle, a power-assisted bicycle, and a railway vehicle. The vehicle on which the battery pack80is mounted includes an automated guided vehicle (AGV) used in a factory or the like.

FIG.17shows an example of application of the above-described battery pack80to a vehicle100. In the example shown inFIG.17, the vehicle100includes a vehicle body101and the battery pack80. In the example shown inFIG.17, the vehicle100is a four-wheeled automobile. A plurality of battery packs80may be mounted on the vehicle100.

In the example ofFIG.17, the battery pack80is mounted in an engine room located in front of the vehicle body101. The battery pack80may be mounted, for example, behind the vehicle body101or under the seat. In particular, the battery pack80including the above-described battery module40can be arranged even in a narrow space under the seat. As described above, the battery pack80can be used as a power source of the vehicle100. Further, the battery pack80can recover regenerative energy of power of the vehicle100.

According to at least one of the embodiments and examples, a first partition wall partitions a first battery and a second battery and partitions a third battery and a fourth battery in a first direction, and a second partition wall partitions the first battery and the third battery and partitions the second battery and the fourth battery in a second direction. A fastening member fastens a first case member to a second case member at an intersection of the first partition wall and the second partition wall. A case includes at least one of a first rib protruding in the first direction on a surface of the first partition wall and a second rib protruding in the second direction on a surface of the second partition wall. Accordingly, it is possible to provide a battery module in which a plurality of case members forming a case are firmly coupled to each other, each of a plurality of batteries is firmly installed inside the case, and a weight reduction is realized.

While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.