JP2019186042A - Battery module - Google Patents

Abstract

To provide a battery module that can be joined without trimming electrode tabs of battery cells.SOLUTION: A battery module 100 includes: a plurality of stacked battery cells 10 each having an electrode tab 12; a cell case, supporting the stacked battery cells 10 inside, for arranging the electrode tabs 12; and an inter-tab bus bar 40 electrically connecting a pair of electrode tabs 12 adjacent to each other in an aligned state. The inter-tab bus bar 40 includes a clamping portion 40d for clamping the electrode tab 12.SELECTED DRAWING: Figure 17A

Description

  The present invention relates to a battery module.

  Conventionally, a chargeable / dischargeable battery module having a plurality of battery cells is known. For example, Patent Document 1 discloses a battery module in which a positive electrode tab and a negative electrode tab of each battery cell are joined to a bus bar by ultrasonic welding or the like in a plurality of laminated thin battery cells.

Japanese Patent No. 4877373

  In the invention described in Patent Document 1, in order to prevent the electrode tabs of each layer from interfering when the electrode tabs are joined to the bus bar by ultrasonic welding, the electrode tabs do not overlap in a plan view as viewed from above and below. The electrode tab is trimmed. However, when the electrode tab of the battery cell is trimmed, current concentrates at the tip of the remaining electrode tab and heat generation increases, which may lead to a shortened life of the battery cell.

  An object of the present invention made in view of such problems is to provide a battery module that can be joined without trimming the electrode tabs of the battery cells.

In order to solve the above-described problem, a battery module according to an embodiment of the present invention includes:
A plurality of stacked battery cells each having an electrode tab;
A cell case for supporting the stacked battery cells inside and arranging the electrode tabs;
A bus bar between tabs electrically connecting a pair of electrode tabs adjacent to each other in an arrayed state;
With
The inter-tab bus bar has a clamping portion that clamps the electrode tab.

  According to the battery module which concerns on one Embodiment of this invention, it can join, without trimming the electrode tab of a battery cell.

It is a disassembled perspective view which shows the structural example of the assembled battery which concerns on 1st Embodiment. It is an external appearance perspective view which shows the structural example of the assembled battery which concerns on 1st Embodiment. It is a top view of a battery cell. It is a side view of a battery cell. It is a disassembled perspective view which shows the structural example of a battery module. It is the schematic diagram which showed the typical 1st process of assembling a battery module. It is the schematic diagram which showed the typical 2nd process of assembling a battery module. It is the schematic diagram which showed the typical 3rd process of assembling a battery module. It is the schematic diagram which showed the typical 4th process of assembling a battery module. It is the schematic diagram which showed the typical 5th process of assembling a battery module. It is the schematic diagram which showed the typical 6th process of assembling a battery module. It is the schematic diagram which showed the typical 7th process of assembling a battery module. It is the schematic diagram which showed the typical 8th process of assembling a battery module. It is a disassembled perspective view which shows the structural example of an auxiliary machine module. It is a perspective view which shows the assembly example of a battery module and an auxiliary machine module. It is a disassembled perspective view which shows the structural example of an upper case. It is a perspective view which shows the structural example by which the battery module is accommodated in the lower case. It is AA sectional drawing of FIG. It is an enlarged view of the broken-line enclosure part of FIG. It is an enlarged view of the broken-line enclosure part of FIG. It is the expanded sectional view which showed typically the positional relationship of a pair of electrode tab and the bus bar between tabs. It is the top view by the top view which showed typically the welding part of an electrode tab and the bus bar between tabs. It is an enlarged view of the broken-line enclosure part of FIG. FIG. 16 is an enlarged view corresponding to FIG. 15 schematically showing another example of a welded portion between an electrode tab and a bus bar between tabs. It is the expanded sectional view which showed typically the 1st example of the bus bar between tabs of the battery module which concerns on 2nd Embodiment. It is the expanded sectional view which showed typically the 2nd example of the bus bar between tabs of the battery module concerning a 2nd embodiment. It is the expanded sectional view which showed typically the 3rd example of the bus bar between tabs of the battery module which concerns on 2nd Embodiment.

  Hereinafter, an embodiment will be described with reference to the drawings. In the following description, front and rear, left and right, and up and down directions are based on the directions of arrows in the drawing. In one embodiment, as an example, the stacking direction of the plurality of battery cells 10 is described as being in the vertical direction, but is not limited thereto. The stacking direction of the plurality of battery cells 10 may be any other direction.

(First embodiment)
FIG. 1 is an exploded perspective view showing a configuration example of the assembled battery 1 according to the first embodiment. FIG. 2 is an external perspective view showing a configuration example of the assembled battery 1 according to the first embodiment.

  The assembled battery 1 may be used by being mounted on a vehicle such as a vehicle equipped with an internal combustion engine or a hybrid vehicle capable of traveling with the power of both the internal combustion engine and the electric motor. The assembled battery 1 may be mounted under a vehicle seat, for example. The assembled battery 1 may be mounted, for example, in the center console of the vehicle. The assembled battery 1 is not limited to a vehicle, and may be used for other purposes.

  As shown in FIG. 1, the assembled battery 1 includes a battery module 100, an auxiliary machine module 200, a lower case 300, and an upper case 400. The lower case 300 and the upper case 400 are engaged with each other by, for example, a fastening structure such as screwing or a fitting structure such as a claw or a clip. Thereby, a space is formed inside the assembled battery 1. The lower case 300 and the upper case 400 are collectively referred to simply as a case. Battery module 100 and auxiliary machine module 200 are located in a space formed by lower case 300 and upper case 400. The battery module 100 is located on the lower case 300 side. The accessory module 200 is located on the upper case 400 side. That is, the auxiliary machine module 200 is positioned above the battery module 100. The lower case 300 and the upper case 400 are made of, for example, a metal material, but may be made of a resin material.

  The battery module 100 includes a restraint plate 60 positioned above the battery cells 10 stacked in the vertical direction. The restraint plate 60 has a convex portion 62 that protrudes downward toward the battery cell 10. The lower case 300 has a bottom surface 310 located below. The bottom surface 310 has a convex portion 312 that protrudes upward toward the battery cell 10.

  As shown in FIG. 2, the assembled battery 1 includes a positive output terminal 410, a negative output terminal 420, a connector 430, and a gas discharge unit 440 in the upper case 400. The plus output terminal 410 and the minus output terminal 420 are electrically connected to the electrode tab 12 (see FIGS. 3A and 3B) of the battery cell 10 included in the battery module 100. The connector 430 is electrically connected to a relay 220 (see FIG. 6) included in the accessory module 200. The gas discharge unit 440 discharges the gas generated from the battery cell 10 inside the case to the outside of the assembled battery 1.

  3A and 3B are diagrams illustrating a configuration example of the battery cell 10 alone. FIG. 3A is a top view of the battery cell 10. FIG. 3B is a side view of the battery cell 10.

  As shown in FIGS. 3A and 3B, the battery cell 10 includes a pair of exterior members 16 that hold the electrolyte solution, cell electrodes, and the like of the battery cell 10 inside, and a front side and a rear side of the battery cell 10. Negative electrode tab 12n and positive electrode tab 12p. The battery cell 10 may have a flat plate shape as a whole. A portion in which the electrolyte solution, the cell electrode, and the like are held inside by the exterior member 16 is also referred to as a holding portion 18. The portion sealed so as to prevent leakage of contents such as the electrolytic solution by bonding, crimping, or welding the exterior member 16 is also referred to as a sealing portion 19. The thickness of the sealing part 19 in the vertical direction is smaller than the thickness of the holding part 18 in the vertical direction.

  The exterior member 16 may include a laminate film. The outermost layer of the exterior member 16 may include a resin material for ensuring electrical insulation. In other words, the battery cell 10 may have an insulating member on its surface layer. The exterior member 16 may include an insulating layer.

  The battery cell 10 has a first outer surface 11 on each of the front and rear sides. The battery cell 10 has a second outer surface 13 on each of the left side and the right side. The first outer surface 11 and the second outer surface 13 may be configured as end portions of the exterior member 16. The battery cell 10 has a third outer surface 14 on each of the upper side and the lower side of the holding unit 18. The third outer surface 14 may be configured as the outermost layer of the exterior member 16. Surfaces obtained by extending the first outer surface 11, the second outer surface 13, and the third outer surface 14 intersect each other.

  The negative electrode tab 12n and the positive electrode tab 12p are collectively referred to as the electrode tab 12. The negative electrode tab 12n and the positive electrode tab 12p may protrude from the front and rear first outer surfaces 11, respectively. The negative electrode tab 12n and the positive electrode tab 12p may be interchanged. The negative electrode tab 12n and the positive electrode tab 12p may protrude in opposite directions. The negative electrode tab 12n and the positive electrode tab 12p may protrude in the same direction. The battery cell 10 is assumed to be stacked in the vertical direction in a state where the pair of positive electrode tabs 12p and the negative electrode tab 12n are arranged along the front-rear direction.

  The electrode tab 12 may protrude from the center of the first outer surface 11. The electrode tab 12 may protrude substantially parallel to the front-rear direction. The electrode tab 12 may have a tab side surface 17 along the protruding direction. The electrode tab 12 may be flat.

  FIG. 4 is an exploded perspective view showing a configuration example of the battery module 100.

  As shown in FIG. 4, the battery module 100 includes a plurality of battery cells 10 stacked in the vertical direction. The number of battery cells 10 is not limited to 6, and may be 5 or less, or 7 or more. The stacked battery cells 10 may be bonded by an adhesive layer 15 located between the battery cells 10. The battery module 100 may have a heat sink 70 between the stacked battery cells 10. The heat sink 70 may be bonded to the battery cell 10 by the adhesive layer 15.

  The adhesive layer 15 may be provided on the third outer surface 14 of the battery cell 10. The adhesive layer 15 may be provided on one of the upper and lower third outer surfaces 14 of the battery cell 10. The adhesive layer 15 may include an adhesive or a pressure-sensitive adhesive such as a double-sided tape or hot melt. The adhesive layer 15 may be formed by, for example, a method of applying an adhesive to the third outer surface 14 of each battery cell 10 or other various methods. The number of the adhesive layers 15 positioned between the components is not limited to two illustrated in FIG. 4, and may be one or three or more. The shape of the adhesive layer 15 is not limited to the rectangle illustrated in FIG. 4, and may be other various shapes.

  The battery module 100 further includes a first cell case 20 and a second cell case 30. A configuration in which the first cell case 20 and the second cell case 30 are combined is simply referred to as a cell case. The first cell case 20 and the second cell case 30 are located on the left side and the right side of the stacked battery cells 10, respectively. The first cell case 20 and the second cell case 30 house the stacked battery cells 10 in an engaged state. More specifically, the cell case supports the stacked battery cells 10 inside and arranges the electrode tabs 12. Each of the first cell case 20 and the second cell case 30 may have partition plates 23 and 33 that protrude inward from the side surfaces. The partition plates 23 and 33 are located between the sealing portions 19 of the battery cells 10 in a state where the first cell case 20 and the second cell case 30 are engaged.

  The shape of the first cell case 20 is a substantially rectangular frame shape when viewed from above, and is a shape in which the right side is open. In other words, the shape of the first cell case 20 is substantially U-shaped with the right side open. The shape of the second cell case 30 is a substantially rectangular frame shape as viewed from above, and the left side is open. In other words, the shape of the second cell case 30 is substantially U-shaped with the left side open. The 1st cell case 20 and the 2nd cell case 30 become a rectangular frame-like structure seeing from the upper direction by engaging in each open side. It can be said that the shape of the configuration in which the first cell case 20 and the second cell case 30 are engaged is a substantially square shape when viewed from above. The cell case accommodates the stacked battery cells 10 in a frame-like configuration. The portions corresponding to the inside of the frame when viewed from above are the opening 22 and the opening 32 in the first cell case 20 and the second cell case 30, respectively. The first cell case 20 has openings 22 at both ends in the stacking direction of the battery cells 10. The second cell case 30 has openings 32 at both ends in the stacking direction of the battery cells 10.

  The first cell case 20 and the second cell case 30 may be engaged with each other by, for example, an engagement claw provided on one side and an engagement hole provided on the other side. For example, the first cell case 20 and the second cell case 30 each have an engaging portion protruding from an arbitrary surface, and the protruding engaging portion is engaged by being sandwiched by an elastic member such as a clip. May be. The first cell case 20 and the second cell case 30 may be engaged by various fastening structures such as screwing, for example. The first cell case 20 and the second cell case 30 are not limited to these examples, and may be engaged by various methods. By doing in this way, the assembled battery 1 can be assembled easily. As a result, the reliability of the product can be improved.

  The first cell case 20 and the second cell case 30 may include a material having a relatively high rigidity. The 1st cell case 20 and the 2nd cell case 30 may be comprised by the metal material or resin material etc. to which the electrically insulating material, such as PET (Polyethylene Terephthalate) resin, was given to the surface, for example.

  The 2nd cell case 30 has the slit 34 in each front-back direction. In a state where the battery cell 10 is accommodated in the cell case, the electrode tab 12 of the battery cell 10 passes through the slit 34 and protrudes to the outside of the cell case. The number of slits 34 corresponds to the number of battery cells 10.

  The battery module 100 further includes an inter-tab bus bar 40, a total plus bus bar 41, and a total minus bus bar 42 that electrically connect the electrode tabs 12 protruding outward from the cell case. The inter-tab bus bar 40, the total plus bus bar 41, and the total minus bus bar 42 are simply referred to as a bus bar.

  The bus bar is made of a material having electrical conductivity. For example, the bus bar is made of a resin material provided with a metal material or an electrically conductive material. The metal material includes, for example, aluminum or copper. The material constituting the bus bar is determined so as to ensure weldability according to the material constituting the electrode tab 12. The surface of the bus bar may be plated to absorb laser light for laser welding that joins the bus bar and the electrode tab 12.

  The battery cells 10 are stacked such that the positive electrode tabs 12p and the negative electrode tabs 12n are alternately replaced. That is, when the positive electrode tab 12p and the negative electrode tab 12n of one battery cell 10 face forward and backward, respectively, the positive electrode tab 12p and the negative electrode tab 12n of the battery cell 10 stacked next to the battery cell 10 are respectively Facing backwards and forwards.

  The thickness of the inter-tab bus bar 40 is about the same as the thickness of the electrode tab 12 or larger than the thickness of the electrode tab 12. The inter-tab bus bar 40 electrically connects the positive electrode tab 12 p of one battery cell 10 and the negative electrode tab 12 n of the battery cell 10 stacked next to the battery cell 10. By doing in this way, the laminated battery cells 10 are electrically connected in series. When the battery cells 10 are connected in series, the positive electrode tab 12p of the battery cell 10 positioned at the upper end or the lower end is not connected to any battery cell 10. It is assumed that the positive electrode tab 12p of the battery cell 10 positioned at the upper end is not connected to any battery cell 10. The total plus bus bar 41 is connected to the positive electrode tab 12p of the battery cell 10 located at the upper end. In this case, the negative electrode tab 12n of the battery cell 10 located at the lower end is not connected to any battery cell 10. The total minus bus bar 42 is connected to the negative electrode tab 12n of the battery cell 10 located at the lower end. By doing so, a potential difference generated between the total plus bus bar 41 and the total minus bus bar 42 is output as the total voltage of the battery cells 10 electrically connected in series.

  The assembled battery 1 may further include a voltage detection unit. The voltage detection unit may be electrically connected to the electrode tab 12 via the bus bar and detect the terminal voltage of each battery cell 10.

  The battery module 100 further includes a restraint plate 60 that restrains the battery cells 10 stacked in the vertical direction from above. The restraint plate 60 is fastened to the fastening portion 66 provided in the first cell case 20 and the second cell case 30 by the restraint plate fastening member 64. The broken line in FIG. 4 shows an example of the correspondence relationship between the restraint plate fastening member 64 and the fastening portion 66.

  The constraining plate 60 may be configured to include a material having a relatively high rigidity. The restraint plate 60 may be made of only a metal material, for example. The configuration of the constraining plate 60 is not limited to this, and may be a resin material or a metal material having an electrically insulating material such as PET resin on the surface. The shape of the restraint plate 60 may be a substantially flat plate shape. The restraint plate 60 has a convex portion 62. The convex portion 62 of the restraining plate 60 pressurizes the upper surface of the battery cell 10 through the opening portions 22 and 32 of the cell case. By doing so, the stacked battery cells 10 are restrained. Therefore, the battery module 100 can be easily handled. When the restraint plate 60 pressurizes the battery cell 10 through the openings 22 and 32 of the cell case, the force that pressurizes the battery cell 10 is hardly applied to the cell case. As a result, the cell case is unlikely to deteriorate or be damaged.

  The battery module 100 may include an insulating sheet 50 between the battery cells 10 stacked in the vertical direction and the restraint plate 60. That is, the restraint plate 60 may be laminated on the battery cell 10 via the insulating sheet 50. The insulating sheet 50 may be adhered to the battery cell 10 with the adhesive layer 15. The insulating sheet 50 may contact the upper surface of the battery cell 10 positioned at the upper end of the stacked battery cells 10. The insulating sheet 50 may contact the lower surface of the battery cell 10 positioned at the lower end of the stacked battery cells 10. The insulating sheet 50 may include an electrically insulating material such as polyethylene (PE) or polypropylene (PP) resin. The shape of the insulating sheet 50 may be substantially flat, but is not limited thereto. The insulating sheet 50 may be adhered to the constraining plate 60 with the adhesive layer 15. By providing the insulating sheet 50, electrical insulation between the upper surface of the battery cell 10 and the restraining plate 60 can be improved. The restraint plate 60 may be bonded to the battery cell 10 by the adhesive layer 15 without using the insulating sheet 50. When the restraint plate 60 is bonded to the battery cell 10 without the insulating sheet 50 interposed therebetween, the exterior member 16 of the battery cell 10 may include an insulating member layer on the surface layer or the like. The insulating sheet 50 or the insulating member layer positioned between the restraint plate 60 and the battery cell 10 is also referred to as a first insulating layer. When the battery module 100 has the first insulating layer between the restraint plate 60 and the battery cell 10, the electrical insulation between the restraint plate 60 and the battery cell 10 can be improved.

  The first cell case 20 may have a side opening 25 on the left side surface. The second cell case 30 may have a side opening 35 on the side surface in the right direction. When the battery module 100 includes the heat dissipation plate 70, a portion protruding in the left-right direction from the heat dissipation plate 70 can protrude outside the cell case through the side opening portions 25 and 35.

  FIG. 5A to FIG. 5H are schematic views respectively showing typical first to eighth steps for assembling the battery module 100. The battery module 100 may be assembled along the procedure illustrated in FIGS. 5A to 5H.

  In the step shown in FIG. 5A, a jig 90 is used to assemble the battery module 100. The jig 90 may be configured such that the battery cell 10 or the heat radiating plate 70 placed thereon is aligned.

  In the process shown in FIG. 5B, the battery cell 10 is placed on the jig 90. The jig 90 may have inner surfaces corresponding to the shapes of the first outer surface 11 and the second outer surface 13 of the battery cell 10 so that the battery cell 10 is placed in an aligned state. The jig 90 may have a shape corresponding to the electrode tab 12 protruding from the central portion of the first outer surface 11 of the battery cell 10. An adhesive layer 15 may be provided on the upper surface or the lower surface of the battery cell 10.

  In the step shown in FIG. 5C, the heat radiating plate 70 is placed on the jig 90. The jig 90 may have a boss 92 and a step so that the radiator plate 70 and the like can be aligned and placed. The heat radiating plate 70 may have a protrusion and a hole 72 at the end that are used when the battery module 100 is fastened to the lower case 300. The heat radiating plate 70 may be aligned by the protrusions coming into contact with the steps of the jig 90 and the holes 72 fitting into the bosses 92 of the jig 90.

  In the step shown in FIG. 5D, an insulating sheet 50 may be further placed on the upper surface of the stacked battery cells 10. An adhesive layer 15 may be provided on the upper surface of the insulating sheet 50.

  In the step shown in FIG. 5E, the second cell case 30 is inserted into the configuration in which at least the battery cells 10 are stacked. At that time, the partition plate 33 of the second cell case 30 is inserted between the sealing portions 19 of the stacked battery cells 10. The configuration in which the battery cells 10 are stacked is aligned even when the battery cells 10 are taken out of the jig 90 by bonding the battery cells 10 to each other or the battery cell 10 and another configuration by the adhesive layer 15. Can be maintained.

  5F, the first cell case 20 is inserted from the opposite side of the second cell case 30 to the configuration in which the battery cells 10 are stacked. At that time, the partition plate 23 of the first cell case 20 is inserted between the sealing portions 19 of the stacked battery cells 10. The electrode tab 12 of the battery cell 10 protrudes from the slit 34 of the second cell case 30 to the outside.

  In the step shown in FIG. 5G, the inter-tab bus bar 40, the total plus bus bar 41, and the total minus bus bar 42 are electrically connected to the electrode tab 12. The bus bar and the electrode tab 12 may be electrically connected, for example, by welding or welding. When the positive electrode tab 12p and the negative electrode tab 12n of the adjacent battery cells 10 are joined to the inter-tab bus bar 40 by welding, the battery cells 10 are joined with high accuracy by maintaining the aligned state. sell.

  Further, the constraining plate 60 is attached from the upper surface to the configuration in which the configuration in which the battery cells 10 are stacked is accommodated in the cell case. The convex portion 62 of the restraining plate 60 abuts the upper surface of the configuration in which the battery cells 10 are stacked through the opening portions 22 and 32 of the cell case. The restraint plate 60 may be bonded to the configuration in which the battery cells 10 are stacked by the adhesive layer 15.

  5H, the restraint plate 60 may be fastened to the cell case by the restraint plate fastening member 64. When the restraint plate 60 is fastened to the cell case, the assembly of the battery module 100 is completed.

  When the battery module 100 is assembled along the processes illustrated in FIGS. 5A to 5H, the positioning accuracy of the electrode tabs 12 of the battery cells 10 stacked adjacent to each other can be improved. As a result, the electrode tab 12 and the bus bar can be easily joined with high accuracy, and the reliability of the assembled battery 1 can be improved.

  Durability when the battery module 100 is subjected to vibration, impact, or the like because the stacked portions of the battery cell 10, the heat dissipation plate 70, the insulating sheet 50, the restraint plate 60, and the like are bonded by the adhesive layer 15. Can be improved. For example, when the assembled battery 1 having the battery module 100 is mounted on a vehicle, the relative displacement of each part of the battery module 100 can be reduced due to vibration or impact when the vehicle travels. By adhering each part of the battery module 100, each part is less likely to be damaged even when subjected to vibration or impact.

  Since the first cell case 20 and the second cell case 30 have the partition plates 23 and 33 positioned between the sealing portions 19 of the battery cells 10, the battery cells 10 are easily insulated from each other. For example, even when the battery cells 10 are deteriorated and deformed with time, the battery cells 10 that are stacked adjacent to each other are less likely to contact each other.

  Since the cell case is made of a metal material or a resin material having an electrically insulating material on its surface, the electrical components and the like located inside the assembled battery 1 and the battery cell 10 are electrically connected to each other. Can be insulated.

  Further, even when the lower case 300 and the upper case 400 of the assembled battery 1 are made of metal, it is possible to ensure insulation between the battery cell 10 and the electrical components and the like located outside the assembled battery 1. In addition, if the lower case 300 and the upper case 400 are made of a resin material, the battery cell 10 and the electric parts located outside the assembled battery 1 are similarly connected even if the cell case is made of a metal material. Insulation can be ensured.

  FIG. 6 is an exploded perspective view showing a configuration example of the accessory module 200.

  As shown in FIG. 6, the auxiliary machine module 200 includes an auxiliary machine base 210, a relay 220, a current sensor 230, a fuse 240, and a substrate 260. Current sensor 230 has a fastening hole 231 at its terminal, and is fastened to fastening portion 212 of auxiliary machine base 210 by fastening member 252. The fastening hole 231 at one end of the current sensor 230 is fastened together with the fastening hole 251 of the copper bus bar 250 that is electrically connected to the relay 220. Relay 220 has a fastening hole 221 at its terminal, and is fastened to fastening portion 212 of auxiliary machine base 210 by fastening member 252. The fastening hole 221 at one end of the relay 220 is fastened together with the fastening hole 251 of the copper bus bar 250 that is electrically connected to the current sensor 230. The fastening hole 221 at the other end of the relay 220 is fastened together with the fastening hole 251 of the copper bus bar 250 that is electrically connected to the fuse 240. The fuse 240 has a fastening hole 241 at its terminal, and is fastened to the fastening portion 212 of the auxiliary machine base 210 by a fastening member 252. The fastening hole 241 at one end of the fuse 240 is fastened together with the fastening hole 251 of the copper bus bar 250 that is electrically connected to the relay 220. The board 260 has fastening holes 261 at four corners, for example, and is fastened to the fastening part 214 of the auxiliary machine base 210 by fastening members 262. The auxiliary machine base 210 has a fastening hole 216. When the auxiliary module 200 is housed in the lower case 300 together with the battery module 100, the module fastening member 270 (see FIG. 7) passes through the fastening hole 216, so that the fastening portion 340 (FIG. 1) of the lower case 300 is obtained. Reference).

  FIG. 7 is a perspective view showing an assembly example of the battery module 100 and the auxiliary machine module 200.

  As shown in FIG. 7, the accessory base 210 of the accessory module 200 is fastened to the first cell case 20 and the second cell case 30 by a module fastening member 270. The module fastening member 270 can be fastened to the fastening portion 340 (see FIG. 1) of the lower case 300 by combining the accessory module 200 and the battery module 100. The current sensor 230 is electrically connected to the copper bus bar 250 electrically connected to the total plus bus bar 41 at a terminal different from the side electrically connected to the relay 220.

  The assembled battery 1 further includes a plus output terminal 410 and a minus output terminal 420. The fuse 240 is electrically connected to the plus output terminal bus bar 412 electrically connected to the plus output terminal 410 at a terminal different from the side electrically connected to the relay 220. That is, the plus output terminal 410 is electrically connected to the total plus bus bar 41 via the fuse 240, the relay 220, and the current sensor 230 that are connected in series. The minus output terminal 420 is electrically connected to the total minus bus bar 42 via the minus output terminal bus bar 422. The positive output terminal 410 may be fastened to the fastening portion 330 (see FIG. 1) of the lower case 300 by screwing in the fastening hole 414 or the like. The minus output terminal 420 may be fastened to the lower case 300 by screwing in the fastening hole 424 or the like.

  The assembled battery 1 may further include a bus bar cover 80 that covers the inter-tab bus bar 40, the total plus bus bar 41, and the total minus bus bar 42. By covering the bus bar with the bus bar cover 80, even if the assembled battery 1 receives an impact such as a collision, and is deformed or damaged, the electrical insulation between the bus bar and the lower case 300 is ensured. Can be raised more.

  The relay 220 functions as a switching element that connects or disconnects the battery cell 10 and the plus output terminal 410.

  The current sensor 230 detects the magnitude of the current flowing from the battery cell 10 to the positive output terminal 410. The current sensor 230 may output the detected current magnitude to the substrate 260.

  The fuse 240 may include a fuse body, an insulating resin housing that houses and holds the fuse body, and an insulating resin cover that covers the housing. The fuse 240 is blown by the overcurrent flowing.

  The substrate 260 may have a BMS (Battery Management System). BMS is also called a battery controller. The BMS may be configured including at least one processor. The BMS may be communicably connected to the current sensor 230 and may acquire a current detection result from the current sensor 230. The BMS may be communicably connected to the relay 220 and may output information for controlling the opening and closing of the relay 220. The BMS may be electrically connected to the inter-tab bus bar 40 and detect the potential of the inter-tab bus bar 40. The BMS may be communicably connected to a sensor that detects the potential of the inter-tab bus bar 40, and may acquire a detection result of the potential of the inter-tab bus bar 40. The BMS may output information on the battery cell 10 to the outside through the connector 430 (see FIG. 8).

  FIG. 8 is an exploded perspective view showing a configuration example of the upper case 400.

  As shown in FIG. 8, the upper case 400 includes a connector 430 and a gas discharge part 440. The connector 430 is communicably connected to the board 260 of the auxiliary machine module 200. The connector 430 may be connectable to an external circuit such as an ECU (Electric Control Unit) of a vehicle on which the assembled battery 1 is mounted, for example.

  The upper case 400 includes a fastening portion 450 that is fastened to the fastening portion 320 (see FIG. 9) of the lower case 300. The fastening portion 320 of the lower case 300 and the fastening portion 450 of the upper case 400 may be fastened by screwing or the like, or may be fastened by an elastic member such as a clip. A case configured by fastening the upper case 400 and the lower case 300 may protect the battery module 100 by surrounding the battery module 100.

  The battery cell 10 can deteriorate over time by repeating charge and discharge. As the battery cell 10 deteriorates with time, gas due to decomposition or volatilization of the electrolytic solution may be generated inside the battery cell 10. When the pressure of the gas inside the battery cell 10 exceeds a predetermined value, the gas can be released from a part of the sealing portion 19 of the battery cell 10 to the outside. The gas released from the inside of the battery cell 10 can accumulate in the space inside the assembled battery 1 surrounded by the lower case 300 and the upper case 400. The gas accumulated in the space inside the assembled battery 1 can be discharged to the outside of the assembled battery 1 through the gas discharge portion 440 of the upper case 400. The gas discharge unit 440 is provided on the upper surface of the upper case 400, but is not limited thereto, and may be provided on the side surface of the upper case 400, or the bottom surface 310 (see FIG. 10) or the side surface of the lower case 300. May be provided.

  The gas discharge unit 440 includes a gas cover 442 and a breather 444. The gas cover 442 can protect the breather 444 from an external impact or the like by covering the breather 444. The breather 444 has an internal pressure adjusting film having air permeability and waterproof and dustproof properties in a gas discharge path. Since the gas discharge unit 440 includes the breather 444, the gas accumulated in the space inside the assembled battery 1 is discharged to the outside of the assembled battery 1, and water, dust, or the like is discharged from the outside of the assembled battery 1 to the assembled battery. It becomes difficult to enter the inside of 1. As a result, the reliability of the assembled battery 1 can be improved.

  FIG. 9 is a perspective view illustrating a configuration example in which the battery module 100 is accommodated in the lower case 300.

  As shown in FIG. 9, the battery module 100 is fastened to the fastening portion 340 (see FIG. 1) of the lower case 300 while being housed in the lower case 300. When the auxiliary machine module 200 is mounted on the upper part of the battery module 100, the auxiliary machine base 210 and the cell case are collectively fastened to the fastening portion 340 of the lower case 300 by the module fastening member 270 (see FIG. 7). .

  FIG. 10 is a cross-sectional view taken along the line AA of FIG. FIG. 11 is an enlarged view of a portion surrounded by a broken line in FIG.

  As shown in FIGS. 10 and 11, the lower case 300 has a bottom surface 310 on the lower side. In a state where the battery module 100 is accommodated in the lower case 300, the stacked battery cells 10 are pressurized from the bottom surface 310 positioned below and the restraining plate 60 positioned above. In other words, the bottom surface 310 of the lower case 300 presses the battery cell 10 from the side opposite to the side where the restraint plate 60 presses the battery cell 10. It can be said that the stacked battery cells 10 are sandwiched between the bottom surface 310 and the restraint plate 60. The stacked battery cells 10 can be stably stored in the lower case 300 by being sandwiched. Since the bottom surface 310 of the lower case 300 has a function of pressing the battery cell 10 from the lower side, a member only for pressing the battery cell 10 from the lower side can be omitted. As a result, the assembled battery 1 can be reduced in size and weight, and the cost can be reduced, and the reliability of the holding structure of the battery cell 10 can be improved.

  The bottom surface 310 may come into contact with the lower surface of the battery cell 10 via the insulating sheet 50. The insulating sheet 50 may be bonded to the bottom surface 310 by the adhesive layer 15. By providing the insulating sheet 50, electrical insulation between the lower surface of the battery cell 10 and the bottom surface 310 of the lower case 300 can be improved. The bottom surface 310 may be bonded to the battery cell 10 by the adhesive layer 15 without using the insulating sheet 50. When the bottom surface 310 is bonded to the battery cell 10 without the insulating sheet 50 interposed therebetween, the exterior member 16 of the battery cell 10 may include an insulating member layer on the surface layer or the like. The insulating sheet 50 or the insulating member layer positioned between the bottom surface 310 and the battery cell 10 is also referred to as a second insulating layer. When the battery module 100 has the second insulating layer between the bottom surface 310 and the battery cell 10, electrical insulation between the battery cell 10 and the lower case 300 can be improved.

  The bottom surface 310 has a convex portion 312 that protrudes upward. The convex portion 312 can contact a predetermined range including the center of the lower surface of the battery cell 10 through the openings 22 and 32 of the cell case. The convex portion 62 of the restraint plate 60 positioned above the battery module 100 can contact a predetermined range including the center of the upper surface of the battery cell 10 through the openings 22 and 32 of the cell case. The convex part 62 may contact the upper surface of the battery cell 10 through another configuration such as the insulating sheet 50. In a state where the battery module 100 is housed in the lower case 300, the stacked battery cells 10 are sandwiched between the convex portion 312 located below and the convex portion 62 located above. The stacked battery cells 10 are firmly restrained by being sandwiched from both the upper and lower sides. The stacked battery cells 10 are pressed by the convex portions 62 and the convex portions 312 in a predetermined range including the center of each of the upper and lower surfaces. The battery cell 10 can be pressed with a larger force in the central portion than the peripheral portion close to the sealing portion 19 among the upper surface and the lower surface of the holding portion 18.

  The battery cell 10 can deteriorate over time by repeating charge and discharge. As the battery cell 10 deteriorates with time, gas due to decomposition or volatilization of the electrolytic solution may be generated inside the battery cell 10. The gas generated inside the battery cell 10 can expand the battery cell 10. The stacked battery cells 10 are less likely to expand in the direction in which the battery cells 10 are stacked by being pressed from above and below by the convex portions 62 of the restraint plate 60 and the convex portions 312 of the bottom surface 310.

  As shown in FIG. 11, the second cell case 30 includes a housing portion 36 in which a pair of electrode tabs 12 connected to the inter-tab bus bar 40 are disposed. More specifically, the inter-tab bus bar 40 and a pair of positive electrode tab 12p and negative electrode tab 12n connected to the inter-tab bus bar 40 are arranged in the accommodating portion 36. The second cell case 30 includes an insulating portion 37 that separates the pair of electrode tabs 12 disposed in the housing portion 36 from the other electrode tabs 12 adjacent to each other. The insulating portion 37 electrically insulates the pair of electrode tabs 12 disposed in the accommodating portion 36 from the adjacent other electrode tabs 12 along the arrangement direction of the electrode tabs 12, that is, the vertical direction.

  12 is an enlarged view of a portion surrounded by a broken line in FIG. FIG. 13 is an enlarged cross-sectional view schematically showing the positional relationship between the pair of electrode tabs 12 and the inter-tab bus bar 40. FIG. 14 is a plan view from the top view schematically showing the welded portion W1 between the electrode tab 12 and the inter-tab bus bar 40. FIG. FIG. 15 is an enlarged view of a portion surrounded by a broken line in FIG. FIG. 16 is an enlarged view corresponding to FIG. 15 schematically showing another example of the welded portions W1 and W2 between the electrode tab 12 and the inter-tab bus bar 40. FIG.

  As shown in FIG. 12, the inter-tab bus bar 40 is attached to the second cell case 30 by an arbitrary method such as screwing through a fastening hole 40a. The above-described voltage detection unit that detects the terminal voltage of each battery cell 10 may be attached to the fastening hole 40a.

  The pair of electrode tabs 12 that are electrically connected to the inter-tab bus bar 40 overlap each other in a plan view as viewed from the arrangement direction of the electrode tabs 12. More specifically, the pair of electrode tabs 12 protrude from the pair of battery cells 10 at positions and shapes corresponding to each other along the width direction intersecting the arrangement direction, that is, the left-right direction. More specifically, the pair of positive electrode tab 12p and negative electrode tab 12n are formed such that the protruding position in the left-right direction and the overall shape are substantially the same.

  As shown in FIG. 13, the inter-tab bus bar 40 is formed in a substantially U shape in a plan view viewed from the left-right direction. A substantially U-shaped inter-tab bus bar 40 is disposed between the pair of positive electrode tab 12p and negative electrode tab 12n. When the inter-tab bus bar 40 is disposed, the inter-tab bus bar 40 is positioned in the front-rear direction by the outer surface parallel to the vertical direction abutting the outer surface of the second cell case 30, for example. The vertical width of the inter-tab bus bar 40 and the vertical distance between the pair of positive electrode tab 12p and negative electrode tab 12n are substantially the same. That is, when the inter-tab bus bar 40 is disposed, the upper surface and the negative electrode tab 12n are in contact with or close to each other, and the lower surface and the positive electrode tab 12p are in contact with or close to each other. In such a state, the inter-tab bus bar 40 and the electrode tab 12 are brought into contact with each other using a fixing jig such as a clip. Laser light is irradiated from above in a state of being in contact with each other, and the upper surface of the inter-tab bus bar 40 and the negative electrode tab 12n are joined to each other by laser welding. As described above, the welded portion W1 is formed. Similarly, laser light is irradiated from below, and the lower surface of the inter-tab bus bar 40 and the positive electrode tab 12p are joined to each other by laser welding. As described above, the welded portion W2 is formed.

  One of the front end surface of the electrode tab 12 and the front end surface of the inter-tab bus bar 40 is disposed on the opposite side of the cell case from the other. The electrode tab 12 and the inter-tab bus bar 40 are joined to each other by laser welding in the vicinity of one of the tip surfaces arranged on the cell case side. As shown in FIGS. 14 and 15, for example, the front end surface of the inter-tab bus bar 40 in the front-rear direction is disposed on the opposite side of the cell case from the front end surface of the electrode tab 12 in the front-rear direction. At this time, the electrode tab 12 and the inter-tab bus bar 40 are joined to each other by laser welding in the vicinity of the front end surface of the electrode tab 12 arranged on the cell case side. The welds W1 and W2 extend linearly along the left-right direction in the vicinity of the tip surface of the electrode tab 12. The positional relationship between the distal end surface of the electrode tab 12 and the distal end surface of the inter-tab bus bar 40 is not limited to the relationship shown in FIG. As shown in FIG. 16, for example, the front end surface in the front-rear direction of the electrode tab 12 may be disposed on the opposite side of the cell case from the front end surface in the front-rear direction of the inter-tab bus bar 40. At this time, the electrode tab 12 and the inter-tab bus bar 40 are joined to each other by laser welding in the vicinity of the front end surface of the inter-tab bus bar 40 arranged on the cell case side. The welds W1 and W2 extend linearly along the left-right direction in the vicinity of the front end surface of the inter-tab bus bar 40.

  According to the battery module 100 according to the first embodiment as described above, the electrode tabs 12 of the battery cells 10 can be joined without trimming. The battery module 100 includes the substantially U-shaped inter-tab bus bar 40, thereby enabling laser welding from the same direction to each contact portion of the plurality of positive electrode tabs 12 p and the inter-tab bus bar 40. Similarly, the battery module 100 has a substantially U-shaped inter-tab bus bar 40, so that laser welding from the same direction can be performed on each contact portion of the plurality of negative electrode tabs 12n and the inter-tab bus bar 40. And In addition, unlike the prior art, it is not necessary to trim the electrode tabs 12 so as not to overlap each other along the vertical direction, and the positions of the contact portions in the horizontal direction are substantially the same. Therefore, in the width direction of the electrode tab 12, that is, in the left-right direction, the irradiation position of the laser beam to each contact portion is substantially the same. As described above, the processes related to laser welding are simplified, and the efficiency of welding work is improved. Therefore, the productivity of the battery module 100 is improved and the production cost is also reduced.

  Since the pair of electrode tabs 12 arranged in the accommodating portion 36 and the other adjacent electrode tabs 12 are electrically insulated by the insulating portion 37 of the second cell case 30, the reliability of the battery module 100 is improved. As a result, the reliability of the assembled battery 1 as a product is also improved. Since the cell case and the insulating portion 37 are made of a resin material or a metal material having an electrically insulating material applied to the surface, the insulating property is improved and the reliability of the assembled battery 1 as a product is further improved.

  Since the inter-tab bus bar 40 is formed in a substantially U-shape in plan view, it can be arranged between the pair of electrode tabs 12 formed in a flat plate shape in contact with each other in a plane. . Therefore, since the battery module 100 can be joined to the inter-tab bus bar 40 without trimming the electrode tab 12 of the battery cell 10, the productivity of the battery module 100 is improved and the production cost is also reduced.

  Since either one of the front end surface of the electrode tab 12 or the front end surface of the inter-tab bus bar 40 is disposed on the opposite side of the cell case from the other, laser welding thereof is facilitated. For example, when the electrode tab 12 and the inter-tab bus bar 40 are joined by laser welding, it becomes easy to identify the irradiation position of the laser beam, and the laser weldability is improved.

  The electrode tab 12 and the inter-tab bus bar 40 are joined to each other in the vicinity of one of the tip surfaces arranged on the cell case side, so that reflection of laser light used for laser welding is suppressed, and laser weldability is improved. Further improve. For example, in the arrangement shown in FIG. 15, when laser light is irradiated on the upper and lower surfaces of the electrode tab 12 at a position closer to the cell case than in the vicinity of the tip surface of the electrode tab 12, the laser light is reflected and is necessary for welding. There is a risk that the amount of heat is not sufficiently transferred. As shown in FIG. 15 or FIG. 16, the welded portions W1 and W2 are formed at the corners of the respective constituent portions, whereby the laser light absorption rate is improved and the laser weldability is further improved. In addition, visual inspection or visual inspection of the welding state is easy even after welding.

  By performing laser welding in the arrangement as shown in FIG. 16, the welded portions W1 and W2 are formed inside the pair of electrode tabs 12, and the open portion of the substantially U-shaped inter-tab bus bar 40 is the welded portion. It is arranged closer to the cell case than W1 and W2. As a result, the electrode tabs 12 or the fragments of the inter-tab bus bar 40 generated by laser welding are scattered inside the substantially U-shaped portion of the inter-tab bus bar 40. Therefore, these pieces are collected in the inter-tab bus bar 40, and the influence on each component of the battery module 100 is suppressed. Since it is not necessary to separately provide a configuration for suppressing the influence of debris associated with laser welding, the number of parts is reduced and the productivity of the battery module 100 is improved.

  Since the electrode tab 12 and the inter-tab bus bar 40 are joined to each other by laser welding, the contact resistance is reduced, and the charge / discharge resistance is reduced. Therefore, heat generation is suppressed and the battery cell 10 has a long life. As a result, the reliability of the assembled battery 1 as a product is improved.

  Since the surface of the inter-tab bus bar 40 is plated to absorb laser light for laser welding, oxidation of the inter-tab bus bar 40 is suppressed, and the absorption rate of the laser light is improved. Therefore, the laser weldability between the pair of electrode tabs 12 and the inter-tab bus bar 40 is improved.

  The restraint plate 60 and the bottom surface 310 pressurize the stacked battery cells 10 through the openings 22 and 32 of the cell case. That is, the cell case is not directly pressurized by the restraint plate 60 and the bottom surface 310. Since the cell case is not pressurized, the cell case becomes difficult to bend. As a result, the cell case is hardly damaged.

  When the restraint plate 60 is made of a metal material, the rigidity of the restraint plate 60 can be improved. As a result, the battery cell 10 is less likely to expand in the direction in which the battery cells 10 are stacked, and the vertical position of the battery cell 10 can be regulated. When the restraint plate 60 includes a metal material provided with a resin material or an electrically insulating material, the electrical insulating property can be improved. When the restraint plate 60 is made of a resin material, the assembled battery 1 can be reduced in weight and manufactured at low cost.

  When the battery cell 10 is pressurized near the center of the upper surface and the lower surface of the holding portion 18, the gas generated inside the battery cell 10 can be collected in a peripheral portion near the sealing portion 19. When the pressure of the gas generated inside the battery cell 10 exceeds a predetermined value, the gas can be released from the sealing portion 19 to the outside of the battery cell 10. When the gas is collected in a peripheral portion close to the sealing portion 19, the gas is easily released to the outside of the battery cell 10. That is, when the battery cell 10 is pressurized near the center of the upper surface and the lower surface of the holding portion 18, the gas is easily released to the outside of the battery cell 10. As a result, the reliability of the battery cell 10 can be improved.

  Since the battery module 100 includes the insulating sheet 50, electrical insulation between the restraint plate 60 and the internal battery cell 10 can be ensured.

  Since the positive electrode tab 12p and the negative electrode tab 12n of the battery cell 10 protrude in opposite directions along the front-rear direction, the symmetry of the cell case can be improved. By doing in this way, a cell case can be formed with sufficient balance.

  The inter-tab bus bar 40 may be wider on the opening side of the substantially U-shaped portion than the end portion on the opposite side. More specifically, for example, in FIG. 16, the vertical width of the front end of the inter-tab bus bar 40 may be larger than the vertical width of the rear end. Thus, when the inter-tab bus bar 40 is formed so that the opening of the inter-tab bus bar 40 is further opened, the contact property between the components is improved when the inter-tab bus bar 40 is disposed between the pair of electrode tabs 12. As a result, laser weldability is improved.

  The shape of the inter-tab bus bar 40 is not limited to a substantially U-shape. As long as the laser weldability can be maintained, the inter-tab bus bar 40 may be formed in an arbitrary shape. For example, the inter-tab bus bar 40 may be formed in a substantially H-shape. For example, the inter-tab bus bar 40 may be formed in a substantially U-shape that is inverted back and forth. For example, the inter-tab bus bar 40 may be formed in a block shape. For example, the inter-tab bus bar 40 may be formed in a plate shape.

  The total plus bus bar 41 and the positive electrode tab 12p are joined to each other by laser welding in the vicinity of one of the front end surfaces arranged on the cell case side, similarly to the laser welding of the inter-tab bus bar 40 and the electrode tab 12. Also good. The total minus bus bar 42 and the negative electrode tab 12n are joined to each other by laser welding in the vicinity of one of the front end surfaces arranged on the cell case side, similarly to the laser welding of the inter-tab bus bar 40 and the electrode tab 12. May be.

  As long as the reflection of the laser beam used for laser welding can be suppressed, the electrode tab 12 and the inter-tab bus bar 40 may be joined to each other not at the vicinity of the tip surface but at a position closer to the cell case.

(Second Embodiment)
FIG. 17A is an enlarged cross-sectional view schematically showing a first example of the inter-tab bus bar 40 of the battery module 100 according to the second embodiment. FIG. 17B is an enlarged cross-sectional view schematically showing a second example of the inter-tab bus bar 40 of the battery module 100 according to the second embodiment. FIG. 17C is an enlarged cross-sectional view schematically showing a third example of the inter-tab bus bar 40 of the battery module 100 according to the second embodiment. In the battery module 100 according to the second embodiment, the configuration of the inter-tab bus bar 40 that is electrically connected to the pair of electrode tabs 12 is different from that of the first embodiment. Below, the same code | symbol is attached | subjected about the component same as 1st Embodiment, and the description is abbreviate | omitted. Differences from the first embodiment will be mainly described.

  The inter-tab bus bar 40 has a pair of end wall portions 40b formed continuously from the front end surface of the substantially U-shaped portion that electrically connects the pair of electrode tabs 12. The inter-tab bus bar 40 includes an elastically deformable elastic portion 40c extending from the end wall portion 40b toward the cell case side. The elastic portion 40 c is formed in a portion different from the substantially U-shaped portion that electrically connects the pair of electrode tabs 12 in the inter-tab bus bar 40. The inter-tab bus bar 40 includes a pair of sandwiching portions 40d configured by a combination of an upper portion or a lower portion of a substantially U-shaped portion extending in the protruding direction of the electrode tab 12, that is, the front-rear direction, and the elastic portion 40c.

  The pair of sandwiching portions 40d sandwich the pair of electrode tabs 12, respectively. More specifically, the distance between the elastic portion 40c included in the holding portion 40d and the upper portion of the substantially U-shaped portion is larger than the plate thickness of the negative electrode tab 12n before the negative electrode tab 12n is inserted. Somewhat small. That is, in a free state where no mechanical load is applied to the elastic portion 40c, the distance between the elastic portion 40c and the upper portion of the substantially U-shaped portion is slightly smaller than the plate thickness of the negative electrode tab 12n. When the negative electrode tab 12n is inserted into the sandwiching portion 40d in this state, the elastic portion 40c is elastically deformed outward. The negative electrode tab 12n is sandwiched between the upper portion of the substantially U-shaped portion and the elastic portion 40c by elastic force received from the elastically deformed elastic portion 40c. Similarly, the positive electrode tab 12p is sandwiched between the lower portion of the substantially U-shaped portion and the elastic portion 40c.

  The end wall portion 40b is formed continuously with the sandwiching portion 40d and opposes the distal end surface in the protruding direction of the electrode tab 12. More specifically, the end wall portion 40b is in contact with the distal end surface in the protruding direction of the electrode tab 12. As shown in FIG. 17A, for example, the end wall portion 40b includes a linear wall extending along the arrangement direction of the electrode tabs 12, that is, the vertical direction. At this time, the end wall portion 40b is disposed substantially parallel to the distal end surface in the protruding direction of the electrode tab 12. The configuration of the end wall portion 40b is not limited to this. The end wall portion 40b may include a wall whose interval in the arrangement direction of the electrode tabs 12 becomes narrower on the tip surface side of the electrode tabs 12. For example, as illustrated in FIG. 17B, the end wall portion 40b may include an R-shaped wall that draws a curve in a plan view viewed from the left-right direction. For example, as illustrated in FIG. 17C, the end wall portion 40b may include a wall that linearly tapers in a plan view viewed from the left-right direction.

  By irradiating laser light toward the outer surface of the end wall portion 40b with the end wall portion 40b facing the tip surface of the electrode tab 12, the inter-tab bus bar 40 and the electrode tab 12 are joined to each other by laser welding. The More specifically, the inner surface of the end wall portion 40b and the negative electrode tab 12n are joined together by laser welding to form a welded portion W1. The inner surface of the end wall portion 40b and the positive electrode tab 12p are joined to each other by laser welding to form a welded portion W2.

  In the battery module 100 according to the second embodiment as described above, the same effect is exhibited with respect to the same configuration as that of the first embodiment. In addition, since the battery module 100 includes the clamping portion 40d, the contact property when the inter-tab bus bar 40 is attached to the electrode tab 12 is improved. As a result, laser weldability is further improved. Since the region capable of laser welding is widened by the end wall portion 40b, the welding reliability is improved.

  The battery module 100 does not require a fixing jig such as a clip for fixing the inter-tab bus bar 40 and the electrode tab 12 during laser welding. In addition, the laser beam can be irradiated from the same direction to the pair of electrode tabs 12 during laser welding. As described above, the processes related to laser welding are simplified, and the efficiency of welding work is improved. Therefore, the productivity of the battery module 100 is improved and the production cost is also reduced.

  In the battery module 100, the welding state can be visually inspected or inspected with an image from the same direction with respect to the welded portions W1 and W2. Therefore, visual inspection of the welding state or inspection by image is easy even after welding.

  Since the vertical distance between the end wall portions 40b becomes narrower on the tip surface side of the electrode tab 12, even when the positions of the battery cells 10 in the stacking direction vary, the end wall portions 40b can correct the displacement. . More specifically, even when the positions vary, the tip surface of the electrode tab 12 is drawn near the tip of the end wall portion 40b. Therefore, the contact property between the inter-tab bus bar 40 and the electrode tab 12 is improved. Since the electrode tab 12 contacts in the vicinity of the front end portion of the end wall portion 40b, the position where the laser beam is irradiated during laser welding can be determined at the front end portion of the end wall portion 40b. As a result, laser weldability is further improved.

  Since the elastic portion 40c is formed in a portion different from the substantially U-shaped portion that electrically connects the pair of electrode tabs 12, there is no need to provide an elastic mechanism in the substantially U-shaped portion. The path length of the character part is the shortest. Accordingly, the energization resistance is reduced. As a result, the calorific value is reduced and the life of the battery cell 10 is prolonged. Thereby, the fuel efficiency is improved and the replacement time is extended, so that the reliability of the assembled battery 1 as a product is improved.

  When the plate thickness of the inter-tab bus bar 40 is larger than the plate thickness of the electrode tab 12, the holding force by the holding portion 40d is increased, and the holding property of the electrode tab 12 by the holding portion 40d is improved.

  It will be apparent to those skilled in the art that the present invention can be realized in other predetermined forms other than the above-described embodiments without departing from the spirit or essential characteristics thereof. Accordingly, the foregoing description is illustrative and not restrictive. The scope of the invention is defined by the appended claims rather than by the foregoing description. Some of all changes that fall within the equivalent scope shall be included therein.

  For example, the shape, arrangement, number, and the like of each component described above are not limited to the contents illustrated in the above description and drawings. The shape, arrangement, number, and the like of each component may be arbitrarily configured as long as the function can be realized.

  For example, the method for assembling the battery module 100 is not limited to the method described above. The battery module 100 may be assembled by any method as long as the battery module 100 can be assembled so that its function is exhibited. For example, the steps in the method for assembling the battery module 100 described above can be rearranged so as not to be logically contradictory, and a plurality of steps can be combined into one or divided.

  The engagement direction between the first cell case 20 and the second cell case 30 is not limited to the left-right direction. As long as the 1st cell case 20 and the 2nd cell case 30 engage so that the function may be exhibited, you may engage along arbitrary directions.

  A restraint plate 60 may also be disposed on the lower surface side of the battery module 100. Thereby, since the battery cell 10 is pinched by the restraint plate 60 with high rigidity from both the upper and lower directions, the pressure holding property is further improved.

  The welding method is not limited to laser welding. The welding method may be any method capable of joining without trimming the electrode tab 12 of the battery cell 10. The welding method may be ultrasonic welding, for example.

1 assembled battery 10 battery cell 11 first outer surface 12 (12p, 12n) electrode tab (positive electrode tab, negative electrode tab)
13 Second outer surface 14 Third outer surface 15 Adhesive layer 16 Exterior member 17 Tab side surface 18 Holding portion 19 Sealing portion 20 First cell case 22 Opening portion 23 Partition plate 25 Side surface opening portion 30 Second cell case 32 Opening portion 33 Partition plate 34 Slit 35 Side opening 36 Housing part 37 Insulating part 40 Inter-tab bus bar 40a Fastening hole 40b End wall part 40c Elastic part 40d Holding part 41 Total plus bus bar 42 Total minus bus bar 50 Insulating sheet 60 Constraining plate 62 Convex part 64 Constraining plate fastening member 66 Fastening part 70 Heat sink 72 Hole 80 Bus bar cover 90 Jig 92 Boss 100 Battery module 200 Auxiliary module 210 Auxiliary machine base 212, 214 Fastening part 216 Fastening hole 220 Relay 221 Fastening hole 230 Current sensor 231 Fastening hole 240 Fuse 241 Fastening hole 250 Copper bus bar 251 Fastening hole 252 Fastening member 260 Substrate 261 Fastening hole 262 Fastening member 270 Module fastening member 300 Lower case 310 Bottom surface 312 Protrusions 320, 330, 340 Fastening portion 400 Upper case 410 Positive output terminal 412 Positive output terminal bus bar 414 Fastening hole 420 Negative output terminal 422 Negative output terminal bus bar 424 Fastening hole 430 Connector 440 Gas discharge part 442 Gas cover 444 Breather 450 Fastening part W1, W2 Welding part

Claims (10)

A plurality of stacked battery cells each having an electrode tab;
A cell case for supporting the stacked battery cells inside and arranging the electrode tabs;
A bus bar between tabs electrically connecting a pair of electrode tabs adjacent to each other in an arrayed state;
With
The inter-tab bus bar has a clamping part that clamps the electrode tabs.
Battery module. The electrode tab protrudes from the outer surface of the battery cell,
The inter-tab bus bar is formed continuously with the sandwiching portion, and further includes an end wall portion facing a front end surface in the protruding direction of the electrode tab.
The battery module according to claim 1. The end wall portion includes a linear wall extending along the arrangement direction of the electrode tabs.
The battery module according to claim 2. The end wall portion includes a wall in which an interval in the arrangement direction of the electrode tabs is narrowed on the tip surface side of the electrode tab.
The battery module according to claim 2. The end wall includes an R-shaped wall;
The battery module according to claim 4. The end wall includes a linearly tapered wall,
The battery module according to claim 4. The clamping part includes an elastic part that can be elastically deformed,
The elastic portion is formed in a portion different from the portion electrically connecting the pair of electrode tabs in the inter-tab bus bar.
The battery module according to any one of claims 1 to 6. The plate thickness of the inter-tab bus bar is larger than the plate thickness of the electrode tab,
The battery module according to any one of claims 1 to 7. The inter-tab bus bar is made of aluminum or copper.
The battery module according to claim 1. The surface of the inter-tab bus bar is subjected to plating for absorbing laser light for laser welding that joins the inter-tab bus bar and the electrode tab.
The battery module according to claim 1.